Distribution of lead and cadmium in trophic levels of some marine organisms.

Mesmar M.

Department of Biological Sciences, Yarmonte University, Irbid, Jorden.

The concentrations of lead and cadmium in two species of algae, two species of invertebrates, and one species of fish (from Fehmern Baltic Sea) were determined using atomic absorption spectrophotometry. The concentrations of these metals at the producer level (algae) were always higher than at the consumer level. Also, among the consumers there was an obvious difference according to feeding habits, in such a way that they could be ranked according to their high content of lead and cadmium as follows: filter feeder (detritous feeder), plankton feeder. In addition, distribution of lead and cadmium varied within the individual producer (Fucus vesiculosus) in such a way that the holdfast exhibited the highest concentration followed by the apcial tip and the branches of the first dichotomy was the lowest. This alga reflects clear selectivity in absorbing more lead than cadmium.

PMID: 3448857 [PubMed - indexed for MEDLINE]

Recording of the ionic efflux during single action potentials in Nitellopsis obtusa by means of high-frequency reflectometry.

Haapanen L, Skoglund CR.

PMID: 6047608 [PubMed - indexed for MEDLINE]

Transfer of mercury and cadmium from terrestrial to aquatic ecosystems.

Huckabee JW, Blaylock BG.

PMID: 4769157 [PubMed - indexed for MEDLINE]

Effects of a sodium-potassium ion-exchanging seaweed preparation in mild hypertension.

Krotkiewski M, Aurell M, Holm G, Grimby G, Szczepanik J.

Department of Rehabilitation, University of Goteborg, Sweden.

A nonpharmacological approach in the treatment of mild hypertension is often advocated. In an attempt to decrease sodium and increase potassium intake, sixty-two middle-aged patients with mild hypertension were given a potassium loaded ion-exchanging sodium-adsorbing potassium-releasing seaweed preparation (seaweed fiber, SF). The mean blood pressure (MBP), evaluated in a double-blind crossover manner with four weeks familiarization and wash-out periods, showed a significant decrease after four weeks on 12 and 24 g/day SF but not on 6 g/day or placebo treatment. Systolic blood pressure during submaximal exercise decreased on all three SF doses. The decrease in MBP appeared to be significantly higher in sodium-sensitive (11.2 mm Hg, P less than .001) than in sodium-insensitive (5.7 mm Hg, P less than .05) patients and was in salt-sensitive patients significantly correlated to the increase in plasma renin activity (PRA). The urinary sodium excretion decreased, the urinary potassium increased and the sodium/potassium urinary excretion ratio decreased, indicating that the decrease of MBP was dependent on the decreased intestinal absorption of sodium and increased absorption of potassium released from the seaweed preparation. A sodium-potassium ion-exchanging seaweed preparation is an effective means of decreasing sodium and increasing potassium intake, and may be used for antihypertensive treatment in mild hypertension.

Publication Types:

Clinical Trial

Controlled Clinical Trial

PMID: 1873002 [PubMed - indexed for MEDLINE]

Evaluation of the metal uptake of several algae strains in a multicomponent matrix utilizing inductively coupled plasma emission spectrometry.

Mahan CA, Majidi V, Holcombe JA.

Three freshwater heat-killed, lyophilized blue-green algae strains have been characterized as to their ability to accumulate heavy metals with a focus on the utilization of these algae as an analytical preconcentration technique. This study examines the metal uptake in several multicomponent mixtures by using inductively coupled plasma optical emission spectrometry (ICP-OES). Six milligrams of a pure strain of algae was added to 20-mL aliquots of buffered (pH 5.5-6.5) multielement solutions containing 0.1, 0.5, 1.0, 2.0, and 4.0 mg/L of K, Mg, Ca, Fe, Sr, Co, Cu, Mn, Ni, V, Zn, As, Cd, Mo, Pb, and Se. All three algae strains exhibit relatively high adsorption affinities for Fe, Pb, and Cu, with uptake between 70 and 98% at the 4 ppm concentration level. Biosorption occurs for essentially every element with the relative affinities decreasing in the order Pb greater than Fe greater than Cu greater than Cd greater than Zn greater than Mn greater than Mo greater than Sr greater than Ni greater than V greater than Se greater than As greater than Co for Chlorella pyrenoidosa at the 4 mg/L concentration level. Although some minor differences were seen, the other algae strains (Stichococcus bacillaris and Chlamydomonas reinharti) displayed similar adsorption behavior over the concentration range studied, indicating similar cell wall binding sites. Langmuirian isotherms exhibited a minimum of two slopes over the concentration range of 0.1-4.0 mg/L, indicating the probable existence of at least two adsorption mechanisms.

PMID: 2729595 [PubMed - indexed for MEDLINE]

Flame atomic absorption spectrometric determination of trace amounts of manganese in alloys and biological samples after preconcentration with the ion pair of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and ammonium tetraphenylborate on microcrystalline naphthalene or by column method.

Taher MA.

Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran. [email protected]

Manganese is quantitatively retained on 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the pH range 7.5-10.5 from large volumes of aqueous solutions of various samples. After filtration, each solid mass consisting of the manganese complex and naphthalene was dissolved with 5 ml of dimethylformamide and the metal was determined by flame atomic absorption spectrometry. Manganese complex can alternatively be quantitatively adsorbed on ammonium tetraphenylborate-naphthalene adsorbent packed in a column and determined similarly. About 0.1 microgram of manganese can be concentrated in a column from 500 ml of aqueous sample, where its concentration is as low as 0.2 ppb. Eight replicate determinations of 1.0 ppm of manganese gave a mean absorbance of 0.224 with a relative standard deviation of 1.8%. The sensitivity for 1% absorption was 19 ppb. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of manganese in various standard samples.

PMID: 11708102 [PubMed - indexed for MEDLINE]

Column chromatographic pre-concentration of iron(III) in alloys and biological samples with 1-nitroso-2-naphthol-3,6-disulphonate and benzyldimethyltetradecylammonium-perchlorate adsorbent supported on naphthalene using atomic absorption spectrometry.

Miura J, Arima S, Satake M.

Faculty of Engineering, Fukui University, Japan.

The solid ion-pair material produced from the reaction between benzyldimethyltetradecylammonium chloride (BDTA) and sodium perchlorate on naphthalene provides the basis for a simple, rapid and selective technique for pre-concentrating iron from up to 500 ml of aqueous solution. Iron reacts with disodium 1-nitroso-2-naphthol-3,6-disulphonate (Nitroso-R salt) to form a water-soluble coloured chelate anion. The iron chelate anion forms a water-insoluble, stable iron-Nitroso-R-BDTA complex on naphthalene packed in a column. Trace amounts of iron are quantitatively retained on naphthalene in the pH range 3.5-7.5 and at a flow-rate of 1-2 ml min-1. The solid mass is dissolved out from the column with 5 ml of N,N-dimethylformamide and iron is determined by means of an atomic absorption spectrometer at 248 nm. The calibration graph is linear for concentrations of iron over the range of 0.5-20 micrograms in 5 ml of final solution. The standard deviation and relative standard deviation were calculated. The detection limit of the method was 0.0196 micrograms ml-1 of iron. The sensitivity for 1% absorption was 0.072 microgram ml-1 (0.165 microgram ml-1 by direct atomic absorption spectrometry of aqueous solution). The proposed method was applied to the determination of iron in standard alloys and biological samples.

PMID: 2091489 [PubMed - indexed for MEDLINE]

Heavy metal determinations in algae and clams and their possible employment for assessing the sea water quality criteria.

Locatelli C, Fabbri D, Torsi G.

Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna, Italy. [email protected]

An empirical criterion for a possible classification of sea water quality is proposed. It is based on the knowledge of metal content in algae (Ulva Rigida) and clams (Tapes Philippinarum), two species present in marine ecosystems. The elements considered are Hg, Cu, Pb, Cd, Zn. The analytical technique employed is Differential Pulse Anodic Stripping Voltammetry (DPASV) in the case of Cu, Pb, Cd, Zn, while the determination of mercury is obtained by the Cold Vapour Atomic Absorption Spectroscopy (CV-AAS) technique with SnCl2 as reducing agent. The analytical procedure has been verified on three standard reference materials: Sea Water BCR-CRM 403, Ulva Lactuca BCR-CRM 279 and Mussel Tissue BCR-CRM 278. For all the elements, in addition to detection limits, accuracy and precision are given: the former, expressed as relative error (e), and the latter, expressed as relative standard deviation (Sr), were in all cases lower than 6%.

PMID: 11554181 [PubMed - indexed for MEDLINE]

Application of the sequential elution technique to determine Cd and Cu cellular location in Ulva lactuca Linnaeus.

Costas RC, Lopez J.

Ecoloxia, Facultade de Ciencias, Campus Lagoas-Marcosende, Universidade de Vigo, 36200 Vigo, Pontevedra, Spain. [email protected]

The sequential elution technique, used to determine the cellular location of metals in nonvascular plants, was adapted to the seaweed Ulva lactuca Linnaeus for the heavy metals Cu and Cd. The optimum conditions for the extraction of extracellular Cu and Cd were determined using specimens previously loaded with these metals. The best extracellular metal extraction media and the number of extracellular metal extraction steps obtained were the following: Two steps (1 h + 40 min) in a filtered sea water-20 mM Ni solution for Cd and two steps in a filtered sea water-50 mM Co solution for Cu. To find these extraction conditions the extracellular metal extraction capacity of the different media used as well as the alteration provoked in plasmalemma permeability were compared. The concentrations of the incubation solutions of Cd and Cu that allowed reliable comparisons between the different extracellular metal extraction media used were previously determined.

PMID: 11598779 [PubMed - indexed for MEDLINE]

Development of an improved rapid enzyme inhibition bioassay with marine and freshwater microalgae using flow cytometry.

Franklin NM, Adams MS, Stauber JL, Lim RP.

Centre for Advanced Analytical Chemistry, CSIRO Energy Technology, Bangor, New South Wales, Australia. [email protected]

A rapid toxicity test based on inhibition of esterase activity in marine and freshwater microalgae (Selenastrum capricornutum, Chlorella sp., Dunaliella tertiolecta, Phaeodactylum tricornutum, Tetraselmis sp., Entomoneis cf. punctulata, Nitzschia cf. paleacea) was developed using flow cytometry. Uptake of fluorescein diacetate (FDA) was optimized for each species by varying the substrate concentration, incubation time, and media pH. Propidium iodide (PI) was utilized to assess membrane integrity. The optimized FDA/PI staining procedure was then used to assess the toxicity of copper in short-term exposures (1-24 h). Esterase activity was a sensitive indicator of copper toxicity in S. capricornutum and E. cf. punctulata. As copper concentrations increased, esterase activity decreased in a concentration-dependent manner. The 3- and 24-h EC50 values (based on mean activity states) were 112 microg Cu L(-1) (95% confidence limits 88-143) and 51 microg Cu L(-1) (95% confidence limits 38-70) for S. capricornutum and 47 microg Cu L(-1) (95% confidence limits 43-51) and 9.1 microg Cu L(-1) (95% confidence limits 7.6-11) for E. cf. punctulata, respectively. This enzyme inhibition endpoint showed similar sensitivity to chronic growth rate inhibition in E. cf. punctulata (48-h and 72-h EC50 values of 17 and 18 microg L(-1), respectively) but was less sensitive compared to growth for S. capricornutum (48-h and 72-h EC50 values of 4.9 and 7.5 microg L(-1), respectively). For the other five species tested, inhibition of FDA fluorescence was relatively insensitive to copper, even at copper concentrations that severely inhibited cell division rate. These short-term bioassays that detect sublethal endpoints may provide a more rapid and cost-effective way of monitoring contaminant impacts in natural waters.

PMID: 11525489 [PubMed - indexed for MEDLINE]

Determination of cadmium partitioning in microalgae and oysters: contribution to the assessment of trophic transfer.

Ettajani H, Berthet B, Amiard JC, Chevolot L.

CNRS, ISOMer, SMAB, Service d'Ecotoxicologie, Nantes, France.

Alternative methodologies have been applied to the study of cadmium transfer in a food chain: water, microalgae (Skeletonema costatum and Tetraselmis suecica), oysters (Crassostrea gigas). The potential bioavailability of Cd in organisms was assessed through partitioning at the cell or tissue levels, and the predictive value of this method was evaluated by determining directly the metal transfer in an experimental food chain model. Cd concentrations were lower in S. costatum than T. suecica, in controls as well as in contaminated algae. In both algal species, Cd was firmly bound to the cell wall or had entered the cell. Cytosolic Cd was bound to intracellular ligands, the biochemical characteristics of which were not consistent with the hypothesis of detoxification via phytochelatins. In both algal species, Cd was predominantly present in the insoluble fraction, but at pHs such as those existing in the digestive tract of bivalves, it was easily extracted from the cells. Thus, exposure to Cd through phytoplanktonic food induced a significant uptake of this metal in soft tissues of bivalves. Due to the difference in Cd accumulation in algae, Cd doses associated with S. costatum were lower than those bound to T. suecica. Moreover, oysters retained a lower percentage of the metal associated with S. costatum compared to T. suecica (9 and 20%, respectively, after 21 days of exposure). Cd doses potentially available to oysters exposed directly in sea water were considerably higher, and direct uptake induced the highest levels of Cd incorporation but only 2% of dissolved Cd was actually retained by oysters over 21 days of exposure. In the soft tissues of oysters, Cd was distributed equally between soluble and insoluble fractions. Cytosolic Cd was present predominantly in the heat-stable fraction and mainly bound to compounds of molecular weight equal to 13.5 kDa. Moreover, a positive correlation was observed between metallothionein-like protein (MTLP) levels and gross concentrations of Cd in the soft tissues of oysters. These data are consistent with the hypothesis of an important role of metallothioneins in Cd metabolism in oysters and suggest a potential availability of MT-bound fraction of Cd to the consumers. These data are in agreement with the response of oysters exposed to Cd in the field.

PMID: 11243323 [PubMed - indexed for MEDLINE]

Bioavailability of metals in stream food webs and hazards to brook trout (Salvelinus fontinalis) in the upper Animas River watershed, Colorado.

Besser JM, Brumbaugh WG, May TW, Church SE, Kimball BA.

U.S. Geological Survey, Columbia Environmental Research Center, 4200 New Haven Road, Columbia, Missouri 65201, USA.

The water quality, habitats, and biota of streams in the upper Animas River watershed of Colorado, USA, are affected by metal contamination associated with acid drainage. We determined metal concentrations in components of the food web of the Animas River and its tributaries-periphyton (aufwuchs), benthic invertebrates, and livers of brook trout (Salvelinus fontinalis)-and evaluated pathways of metal exposure and hazards of metal toxicity to stream biota. Concentrations of the toxic metals cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in periphyton, benthic invertebrates, and trout livers from one or more sites in the upper Animas River were significantly greater than those from reference sites. Periphyton from sites downstream from mixing zones of acid and neutral waters had elevated concentrations of aluminum (Al) and iron (Fe) reflecting deposition of colloidal Fe and Al oxides, and reduced algal biomass. Metal concentrations in benthic invertebrates reflected differences in feeding habits and body size among taxa, with greatest concentrations of Zn, Cu, and Cd in the small mayfly Rhithrogena, which feeds on periphyton, and greatest concentrations of Pb in the small stonefly Zapada, a detritivore. Concentrations of Zn and Pb decreased across each trophic linkage, whereas concentrations of Cu and Cd were similar across several trophic levels, suggesting that Cu and Cd were more efficiently transferred via dietary exposure. Concentrations of Cu in invertebrates and trout livers were more closely associated with impacts on trout populations and invertebrate communities than were concentrations of Zn, Cd, or Pb. Copper concentrations in livers of brook trout from the upper Animas River were substantially greater than background concentrations and approached levels associated with reduced brook trout populations in field studies and with toxic effects on other salmonids in laboratory studies. These results indicate that bioaccumulation and transfer of metals in stream food webs are significant components of metal exposure for stream biota of the upper Animas River watershed and suggest that chronic toxicity of Cu is an important factor limiting the distribution and abundance of brook trout populations in the watershed.

PMID: 11116340 [PubMed - indexed for MEDLINE]

The cell wall as a barrier to uptake of metal ions in the unicellular green alga Chlamydomonas reinhardtii (Chlorophyceae).

Macfie SM, Welbourn PM.

Dept. of Plant Sciences, University of Western Ontario, London, Ontario, N6A 5B7, Canada.

The cell walls of plants, including those of algae, have the capacity to bind metal ions in negatively charged sites. The authors had already shown that the wild type (walled) strain of the unicellular green alga Chlamydomonas reinhardtii Dangeard was more tolerant to Cd, Co, Cu, and Ni than a wall-less mutant of the same species. The objective of the present study was to determine if the tolerance to metals was associated with an increased adsorption of the same metals to the cell wall. Adsorbed metal was defined as that fraction that could be removed with a solution containing Na(2)EDTA and CaCl(2). The fraction that remained after the EDTA/CaCl(2) wash was considered to be strongly bound in the cell. When exposed to metals, singly, in solution for 24 h, cells of both strains accumulated the metals. The original hypothesis was supported by the results for Cd, Co, and Ni insofar as significantly higher concentrations of these metals were in the loosely bound fraction of the walled strain in comparison with the wall-less strain. However, there are three reasons why the potentially protective effect of the cell wall did not explain differential tolerance of the two strains. After 24 h of exposure (1) less Cd was accumulated internally by the wall-less strain than by the walled strain, (2) very little of the accumulated Cu was in the loosely bound fraction of the walled strain, and (3) the two strains accumulated comparable and relatively high amounts of internal Cu. Unexpectedly, significant amounts of Cd and Cu were also removable from the surface of the wall-less cells. One possible explanation for these apparently externally bound metals in the wall-less strain is that the cells exuded metal-chelating molecules that decreased the ability of metal ions to penetrate the plasma membrane. It was concluded that metal tolerance in this alga must involve a complex of mechanisms involving both internal and external detoxification of metal ions.

PMID: 11031300 [PubMed - indexed for MEDLINE]

Experimental kinetic rates of food-chain and waterborne radionuclide transfer to freshwater fish: a basis for the construction of fish contamination charts.

Garnier-Laplace J, Adam C, Baudin JP.

Institut de Protection et de Surete Nucleaire, Departement de Protection de l'Environnement, Laboratoire de Radioecologie Experimentale, centre de Cadarache, Bt 180, BP 1, 13108 Saint Paul lez Durance Cedex, France.

A standardized procedure is proposed to obtain from laboratory experiments the kinetic accumulation and release rates necessary to calibrate dynamic models to quantify radionuclide direct and trophic transfer in fish. The model takes into account the food-chain effect, the feeding rate, and the growth of organisms. It takes as examples (54)Mn, (60)Co, and (137)Cs transfer dynamics through a simple pelagic food-chain (phytoplankton, zooplankton, prey fish, and predator fish). The estimated kinetic rates used in quantifying all the transfers of the three radioactive pollutants through the pelagic food chain are compared from the radioecological point of view. For fish, comparison was based on the calculation of concentration factors referring to direct transfer from water and trophic transfer factors. For the prey fish and the predator fish, direct transfer gave the following order for accumulation (60)Co < (137)Cs < (54)Mn. Values reached at equilibrium in L/kg WW were respectively for the prey fish and the predator fish: 8.7 < 27.4 < 107 and 4.14 < 6.59 < 13.4. For the trophic route, (137)Cs is the most accumulated (TTF(eq) = 0.485 in 291 days for the prey fish and TTF(eq) = 1.45 in 17 years for the predator fish). A sensitivity analysis adapted to the case of a chronic contamination scenario of a watercourse was run. It showed that the phytoplankton biomass, the contact time of these drifting particles from a release point to the station where they are ingested and the feeding rates of the fish are the most influential parameter with regard to the concentration in fish, whatever the trophic level. Contamination charts are constructed for the predator fish to illustrate the relationship between the most influential ecological parameters and the radionuclide concentration in fish for simple contamination scenarios. They are shown to be effective tools for helping in the choice of the most relevant value of aggregated concentration factors (ACFs: radionuclide concentration ratio between the organism and the water, referred to steady-state and to all possible transfer pathways) for a given key ecological situation in a given ecosystem. An example is given of a simple chronic release scenario of 1 Bq/L and a phytoplanktonic bloom period. For (137)Cs, the ACF increases with increasing contact time and increasing feeding rate, to nearly 550 L/kg WW at equilibrium. For (54)Mn, ACF reaches 65 L/kg WW. For (60)Co, the general pattern of the relationship is due to the rapid kinetic rates governing the distribution of the radionuclide between dissolved and solid (phytoplankton) phases with a maximum value for ACF of 7.2 L/kg WW for the case study. Analysis of these charts provides a basis for overall guidelines for chronic releases in a given watercourse.

PMID: 10871415 [PubMed - indexed for MEDLINE]

Cadmium bioaccumulation in Tetraselmis suecica: an electron energy loss spectroscopy (EELS) study.

Nassiri Y, Wery J, Mansot JL, Ginsburger-Vogel T.

Laboratoire de Biologie Marine, Faculte des Sciences et Techniques, CNRS-EP 61, ISOmer, 2 Rue de la Houssiniere BP 92208, 44322 Nantes Cedex 03, France.

Electron energy loss spectroscopy (EELS) was used to study the distribution of cadmium within the microalga Tetraselmis suecica when submitted to cadmium contamination. This analytical technique, which is associated to transmission electron microscopes, demonstrated that cadmium was stored specifically in the osmiophilic vesicles of T. suecica. The EELS study of the oxidation states revealed that cadmium was stored as Cd2+. In addition, the EELS quantification showed a significant relationship between cadmium, nitrogen, and sulfur concentrations. The toxic element is probably bounded to organic molecules via S-Cd bounds.

PMID: 9294243 [PubMed - indexed for MEDLINE]

Ultrastructural and electron energy loss spectroscopy studies of sequestration mechanisms of Cd and Cu in the marine diatom Skeletonema costatum.

Nassiri Y, Mansot JL, Wery J, Ginsburger-Vogel T, Amiard JC.

Laboratoire de Biologie Marine, Faculte des Sciences et Techniques, CNRS-EP 61, ISOMer, 2 Rue de la Houssiniere BP 92208, 44322 Nantes Cedex 03, France.

The marine diatom Skeletonema costatum was used to study mechanisms of detoxification when submitted to cadmium and copper contamination. After 96 h of growth, concentration corresponding to 50% growth inhibition (IC50, 96 h) was 0.224 mg/L for cadmium and 0.045 mg/L for copper, indicating that copper is more toxic for S. costatum than cadmium. Heavy cellular damages were observed for cadmium and copper concentrations close to the IC50. Exposure to these concentrations induced a migration of inclusions from the peripheral cytoplasm to the vacuole. Electron energy loss spectroscopy (EELS) investigations demonstrated that Cd and Cu were specifically trapped in these inclusions. However, Cu was less sequestered than cadmium in the vacuole. EELS determination of oxidation states evidenced that trace metals were sequestered as Cd2+ and Cu2+. Nitrogen and sulfur are involved in metallic storage, especially in the case of cadmium contamination.

PMID: 9294242 [PubMed - indexed for MEDLINE]

Metal accumulation in a biological indicator (Ulva rigida) from the lagoon of Venice (Italy).

Favero N, Cattalini F, Bertaggia D, Albergoni V.

Department of Biology, University of Padova, Via Trieste 75, 35121 Padova, Italy.

Ulva rigida (C. Agardht) was collected from the Palude della Rosa (lagoon of Venice), a particular area characterized by a salinity gradient, from December 1991 to June 1993. Metal contents (Al, Mn, Fe, Cu, Zn, Cr, Co, Ni, Cd, and Pb) were determined by atomic absorption spectrophotometry and statistically analysed for differences between months and sampling sites. The mean seasonal variability is very significant (p < 0.001) for all studied metals. Seasonal trends are comparable for groups of metals according to possible functional similarities. A significant positive correlation was calculated for the pairs Fe-Al and Fe-Pb. Mechanisms regulating metal uptake are discussed, particularly the role of Fe and its linear relationship with Al. Metal concentrations in relation to salinity also were studied. Larger amounts of Fe, Zn, and Cd accumulated in correspondence of lower salinity, may be owing to both higher metal activity and burden of bioavailable metals in freshwater flowing into the Palude. Calculation of concentration factor (CF) indicates that U. rigida specifically accumulates Fe. CF linearly correlates with dissolved metal concentrations, suggesting that U. rigida is a good bioindicator of metal bioavailability, although seasonal active accumulation occurs in some cases (Mn). Metal concentrations determined in this macroalga support the conclusion that the studied area is rich in bioavailable Fe and poor in toxic metals. In any case, a great affinity for Al in U. rigida may be proposed.

PMID: 8687985 [PubMed - indexed for MEDLINE]

Patterns of metal accumulation in Laminaria longicruris from Long Island Sound (Connecticut).

Shimshock N, Sennefelder G, Dueker M, Thurberg F, Yarish C.

Department of Ecology and Evolutionary Biology, University of Connecticut, Stamford 06903.

Laminaria longicruris de la Pyl. samples were harvested from Long Island Sound (Connecticut) from January 1985 to January 1986. Cadmium and copper content was determined by atomic absorption spectrophotometry from four tissue types; young blade, old blade, young stipe and old stipe. The results were statistically analyzed for differences in both type and age of tissue. Concentrations of cadmium were consistently lower than copper concentrations for all months and all tissue types. Statistically significant differences (p greater than 0.05) were found between the four tissue types for copper in the months of March, June, July, October and December, and for cadmium in the months of February, March, June, July, October and November. Young blade tissue and young stipe tissue were the tissues which most frequently found to be statistically different from the other tissues. Young stipe tissue had the lowest trace metal concentrations (1.3 mean ppm, dry wt. Cu, 0.22 mean ppm, dry wt. Cd). Young blade tissue had significantly higher metal values in comparison to the other tissues for the months of June and October. Old tissue of L. longicruris is the most suitable for use in biomonitoring of trace metals due to the relatively little variation in metal content that was found throughout the study period.

PMID: 1616316 [PubMed - indexed for MEDLINE]

Toxicity to estuarine organisms of leachates from chromated copper arsenate treated wood.

Weis P, Weis JS, Coohill LM.

Department of Anatomy, New Jersey Medical School, Newark 07103.

The effects of chromated copper arsenate (CCA), used for treating wood in docks, pilings, and bulkheads, were studied in several estuarine organisms. Leaching of metals from treated wood into sea water was assayed by atomic absorption spectrophotometry. Fiddler crabs (Uca pugilator) were subjected to limb removal and were placed in containers with treated wood of various sizes or control wood. Limb regeneration rate was retarded in a dose-dependent fashion and mortality occurred with the treated wood, reaching 100% in the tank with the largest piece of wood. Embryos of the mummichog (Fundulus heteroclitus) were allowed to develop in culture dishes in which CCA-treated or untreated wood was soaking. Mortality was noted in the dishes with treated wood and to a smaller extent in those with untreated wood. Containers containing CCA-treated wood, control wood, or no wood were stocked first with the alga Ulva lactuca, the snails (Nassarius obsoletus). Chlorophyll content of the algae was reduced with the treated wood within a few days, and snails with the treated wood became moribund and died within a few days. In the controls containing untreated wood or no wood, no such effects were seen. Studies with individual or combination of two or three of the metals with snails and algae indicated that the copper was primarily responsible for the snail mortality and algal bleaching seen in the treated wood experiments. In all experiments, the toxicity of the wood decreased over time; when the experiments were repeated with the same pieces of wood, effects were diminished.

PMID: 1996903 [PubMed - indexed for MEDLINE]

A morphometric and X-ray energy dispersive approach to monitoring pH-altered cadmium toxicity in Anabaena flos-aquae.

Rai LC, Jensen TE, Rachlin JW.

Department of Biological Sciences, Lehman College, Bronx, New York 10468.

Cadmium toxicity and uptake as influenced by different pH values have been studied in the freshwater cyanobacterium Anabaena flos-aquae, using the techniques of morphometric analysis, x-ray energy dispersive analysis and atomic absorption spectrophotometry. A general reduction in cell dimension, thylakoid surface area, number and volume of polyhedral bodies, polyphosphate bodies, cyanophycin granules, lipid bodies, membrane limited crystalline inclusions, volume and number of wall layers and mesosomes was observed. These reductions were more pronounced in both acidic and alkaline medium than at pH 7.2. At 0.12 microM Cd, the uptake increased with alkaline pH values, and uptake was greater at pH 7.2 than at either acid or alkaline pHs. Lysis of cell wall at 1.18 microM Cd showed the following decreasing trend: pH 4.0 greater than pH 5.5 greater than pH 10.0 greater than pH 9.0 greater than pH 7.2. There was a total loss of lipid bodies at 1.18 microM Cd at all pH values listed. It is suggested that these techniques can be successfully employed for bioassay studies of metal toxicity to algae. In particular, cell wall lysis and loss of lipids by algae are good indicators of pH effects and metal toxicity in the aquatic ecosystem.

PMID: 2117425 [PubMed - indexed for MEDLINE]

[Contents of various nutrients, minerals and seasonal fluctuations in Porphyra columbina, an edible marine algae from the Argentine Patagonian++ coast]

[Article in Spanish]

Fajardo MA, Alvarez F, Pucci OH, Martin de Portela ML.

Universidad Nacional de la Patagonia S. Juan Bosco, Argentina.

Porphyra columbina (Rodophyta Bangiales), one of the most important edible seaweeds, grows abundantly in the southern Argentine coast. Their mineral content and seasonal fluctuations were determined because there is no national data about their nutritional value. Samples were collected from April 1993 to February 1994 from Golfo San Jorge (30 Km South of Comodoro Rivadavia). Algae were washed with sea water and dried at room temperature (20-2 degrees C) for 24 hs, following the local processing procedure. Moisture and ashes were determined according to A.O.A.C. After mineralization with nitric acid sodium and potassium were determined by flame photometry; calcium, magnesium and iron by atomic absorption spectrophotometry (AAS); and phosphorus by Gomori's method. The results, expressed per 100 g dry algae showed the following values: moisture content: 7.03 to 11.00 g/100 g; ashes: 16.18 to 22.70 g/100 g; sodium: 3.18 to 6.41 g/100 g; potassium 1.24 to 1.96 g/100 g; magnesium: 600 to 836 mg/100 g; phosphorus: 78 to 276 mg/100 g; calcium: 63 to 108 mg/100 g and iron: 3.9 to 26.4 mg/100 g. The results of composition of algae as manufactured in the region showed important seasonal differences, with the highest values of ashes, sodium, potassium and magnesium in winter season (June and July).

PMID: 9951542 [PubMed - indexed for MEDLINE]

[Effect of alginates from Adriatic Sea algae on the transport of strontium through the duodenum in rats]

[Article in Serbo-Croatian (Roman)]

Gruden N, Kostial K, Turjak-Zebic V, Skaric V.

PMID: 5207400 [PubMed - indexed for MEDLINE]

Synthesis and biological activity of 24xi-1- and 24xi-2-hydroxyvitamin D3+.

Ikekawa N, Morisaki M, Koizumi N, Sawamura M, Tanaka Y.

PMID: 1111531 [PubMed - indexed for MEDLINE]

Identification and characterization of a recombinant metallothionein protein from a marine alga, Fucus vesiculosus.

Morris CA, Nicolaus B, Sampson V, Harwood JL, Kille P.

School of Biosciences, University of Wales Cardiff, P.O. Box 911, Cardiff CF1 3US, Wales, UK.

A cDNA library was constructed from macroalgae adapted to prolonged elevated environmental copper levels. To investigate the possible existence of a metallothionein (MT) gene, the library was screened with degenerate probes designed using plant MT cysteine-rich motifs. A gene was identified (1229 bp) with a putative open reading frame (204 bp) encoding a 67-amino-acid protein exhibiting several characteristic features of MT proteins, including 16 cysteine residues (24%) and only one aromatic residue. Although the protein sequence showed high identity with plant and invertebrate MTs, it contained a unique 'linker' region (14 amino acid residues) between the two putative metal-binding domains which contained no cysteine residues. This extended linker is larger than the tripeptide found in archetypal vertebrate MTs, but does not conform either with the 40-amino-acid linkers commonly found in plant MT sequences. An S-peptide Fucus MT fusion protein expressed in Escherichia coli exhibited a relative molecular mass of approximately 14 kDa. The recombinant fusion bound seven Cd ions, of which 50% were dissociated at pH 4.1. Under anaerobic conditions, the Cd ions were displaced by Cu(I), which associated with the protein at a ratio of 13:1. Laboratory exposure of F. vesiculosus to elevated copper resulted in induction of the MT gene. Thus this paper describes, for the first time, an MT gene identified from macroalgae which is induced by copper exposure and whose encoded protein product binds cadmium and copper.

PMID: 10024535 [PubMed - indexed for MEDLINE]

Purification, properties and amino acid sequence of atypical cytochrome c from two protozoa, Euglena gracilis and Crithidia oncopelti.

Pettigrew GW, Leaver JL, Meyer TE, Ryle AP.

A basic cytochrome was isolated from the phytomastigophorean protozoan Euglena gracilis and a similar protein from the zoomastigophorean protozoan Crithidia oncopelti. In both cases chromatography on CM-cellulose in first the reduced and then the oxidized form proved to be an efficient means of purification. The two cytochromes can be classed in the cytochrome c family but they have certain atypical features. The alpha peak of the absorption spectrum is shifted towards the red and is asymmetrical. The pyridine ferrohaemochrome has an alpha-peak maximum intermediate between that of c-type cytochromes and proteins containing protohaem IX. The test for free vinyl groups was positive. The amino acid sequences of the two cytochromes were determined. Attention is drawn in the text to those parts of the evidence that are less satisfactory. Both sequences are homologous with the family of cytochrome c, but are unusual in having only one cysteine residue so that the haem is attached through only one thioether bond. Detailed evidence for the amino acid dequences of the two proteins has been deposited as Supplementary Publication SUP 50042 (70 pages) at the British Library (Lending Division) (formerly the National Lending Library for Science and Technology), Boston Spa, Wetherby, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1975) 145, 5.

PMID: 170910 [PubMed - indexed for MEDLINE]

Characterisation of caesium transport in the microalga Chlorella salina.

Avery SV, Codd GA, Gadd GM.

Department of Biological Sciences, University of Dundee, U.K.

PMID: 8566362 [PubMed - indexed for MEDLINE]

The active site structure of Thalassiosira weissflogii carbonic anhydrase 1.

Cox EH, McLendon GL, Morel FM, Lane TW, Prince RC, Pickering IJ, George GN.

Center for Environmental Bioinorganic Chemistry, Departments of Chemistry and Geosciences, Princeton University, Princeton, New Jersey 08544, USA.

X-ray absorption spectroscopy at the Zn K-edge indicates that the active site of the marine diatom Thalassiosira weissflogii carbonic anhydrase is strikingly similar to that of mammalian alpha-carbonic anhydrase enzymes. The zinc has three histidine ligands and a single water at 1.98 A. This is quite different from the beta-carbonic anhydrases of higher plants in which zinc is coordinated by two cysteine thiolates, one histidine, and a water molecule. The diatom carbonic anhydrase shows no significant sequence similarity with other carbonic anhydrases and may represent an example of convergent evolution at the molecular level.

PMID: 11015190 [PubMed - indexed for MEDLINE]

Structure and orientation of the oxygen-evolving manganese complex of green algae and higher plants investigated by X-ray absorption linear dichroism spectroscopy on oriented photosystem II membrane particles.

Schiller H, Dittmer J, Iuzzolino L, Dorner W, Meyer-Klaucke W, Sole VA, Nolting H, Dau H.

FB Biologie/Botanik and FB Chemie, Philipps-Universitat Marburg, Germany.

X-ray absorption spectroscopy at the Mn K-edge has been performed on multilayers of photosystem II-enriched fragments of the native thylakoid membrane prepared from a higher plant (spinach) and a unicellular green alga (Scenedesmus obliquus). Spectra collected for various angles between the prevailing orientation of the thylakoid membrane normal and the X-ray electric field vector contain information on the atomic structure of the tetranuclear manganese complex of photosystem II (PS II) and its orientation with respect to the membrane normal. The previously used approach for evaluation of the dichroism of extended X-ray absorption fine structure (EXAFS) spectra [George, G. N., et al. (1989) Science 243, 789-791] is modified, and the following results are obtained for PS II in its dark-stable state (S1-state): (1) structure and orientation of the PS II manganese complexes of green algae and higher plants are highly similiar or fully identical; (2) two 2.7-A vectors, which, most likely, connect the Mn nuclei of a planar Mn2(mu-O2) structure, are at an average angle of 80 degrees +/- 10 degrees with respect to the thylakoid normal; (3) the plane of the Mn2(mu-O2) structures is rather in parallel with the thylakoid plane than perpendicular. Structural models for the oxygen-evolving manganese complex and its orientation in the thylakoid membrane are discussed within the context of the presented results.

PMID: 9585548 [PubMed - indexed for MEDLINE]

A Euglena gracilis zinc endonuclease.

Czupryn M, Falchuk KH, Stankiewicz A, Vallee BL.

Center for Biochemical and Biophysical Sciences and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.

A 26-kDa endonuclease has been purified to homogeneity from zinc-sufficient Euglena gracilis. The protein binds to single-stranded DNA with a higher affinity than to double-stranded DNA, but it exhibits nucleolytic activity toward both. Thus, it converts supercoiled plasmid pBR322 DNA into the linear form, a property characteristic of endonucleases, and it continues to act on the linearized DNA until it is completely degraded. It also hydrolyzes heat-denatured, single-stranded calf thymus DNA. Moreover, at amounts below 1 microgram, it enhances RNA synthesis by RNA polymerase II, a characteristic observed with other DNases. Its addition to an in vitro transcription assay increases RNA synthesis up to 3-fold. The nuclease requires two metal components to carry out its enzymatic activities. It hydrolyzes DNA only in the presence of millimolar amounts of magnesium or micromolar quantities of other activating metal ions, such as manganese, zinc, or cobalt. However, even when optimal concentrations of Mg2+ are present, micromolar amounts of the metal-chelating agents OP and HQSA completely inhibit pBR322 digestion. Transcription enhancement is also inhibited completely by both chelators at concentrations that do not affect the intrinsic polymerase II activity. By atomic absorption spectrometry, the enzyme contains 1 g-atom of Zn/mol, which is the likely target of chelator action. The nuclease protein can also be isolated from zinc-deficient E. gracilis, but remarkably it then contains 1 mol of Cu/g-atom and no zinc.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 8448131 [PubMed - indexed for MEDLINE]

Vanadium K-edge X-ray absorption spectroscopy of bromoperoxidase from Ascophyllum nodosum.

Arber JM, de Boer E, Garner CD, Hasnain SS, Wever R.

Department of Chemistry, University of Manchester, U.K.

Bromoperoxidase from Ascophyllum nodusum was the first vanadium-containing enzyme to be isolated. X-ray absorption spectra have now been collected in order to investigate the coordination of vanadium in the native, native plus bromide, native plus hydrogen peroxide, and dithionite-reduced forms of the enzyme. The edge and X-ray absorption near-edge structures show that, in the four samples studied, it is only on reduction of the native enzyme that the metal site is substantially altered. In addition, these data are consistent with the presence of vanadium(IV) in the reduced enzyme and vanadium(V) in the other samples. Extended X-ray absorption fine structure data confirm that there are structural changes at the metal site on reduction of the native enzyme, notably a lengthening of the average inner-shell distance, and the presence of terminal oxygen together with histidine and oxygen-donating residues.

PMID: 2611224 [PubMed - indexed for MEDLINE]

Comparison of the structure of the manganese complex in the S1 and S2 states of the photosynthetic O2-evolving complex: an x-ray absorption spectroscopy study.

Yachandra VK, Guiles RD, McDermott AE, Cole JL, Britt RD, Dexheimer SL, Sauer K, Klein MP.

Laboratory of Chemical Biodynamics, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.

A Mn-containing enzyme complex is involved in the oxidation of H2O to O2 in algae and higher plants. X-ray absorption spectroscopy is well suited for studying the structure and function of Mn in this enzyme complex. Results of X-ray K-edge and extended X-ray absorption fine structure (EXAFS) studies of Mn in the S1 and S2 states of the photosynthetic O2-evolving complex in photosystem II preparations from spinach are presented in this paper. The S2 state was prepared by illumination at 190 K or by illumination at 277 K in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU); these are protocols that limit the photosystem II reaction center to one turnover. Both methods produce an S2 state characterized by a multiline electron paramagnetic resonance (EPR) signal. An additional protocol, illumination at 140 K, produces as a state characterized by the g = 4.1 EPR signal. We have previously observed a shift to higher energy in the X-ray absorption K-edge energy of Mn upon advancement from the dark-adapted S1 state to the S2 state produced by illumination at 190 K [Goodin, D. B., Yachandra, V. K., Britt, R. D., Sauer, K., & Klein, M. P. (1984) Biochim. Biophys. Acta 767, 209-216]. The Mn K-edge spectrum of the 277 K illuminated sample is similar to that produced at 190 K, indicating that the S2 state is similar when produced at 190 or 277 K.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 3318924 [PubMed - indexed for MEDLINE]

X-ray absorption spectroscopy of cadmium phytochelatin and model systems.

Pickering IJ, Prince RC, George GN, Rauser WE, Wickramasinghe WA, Watson AA, Dameron CT, Dance IG, Fairlie DP, Salt DE.

Stanford Synchrotron Radiation Laboratory, Stanford University, CA 94309, USA. [email protected]

Higher plants, algae and some yeasts respond to potentially toxic heavy metals such as cadmium by synthesizing phytochelatins and related cysteine-rich polypeptides. We have used X-ray absorption spectroscopy to study the nature of cadmium binding in such peptides isolated from maize (Zea mays) exposed to low levels of cadmium, and in two synthetic cadmium-peptide complexes, Cd-(gamma-Glu-Cys)3Gly and Cd-(alpha-Glu-Cys)3Gly. We have used the synthetic ions [Cd(SPh)4]2-, [Cd4(SPh)10]2- and [S4Cd10(SPh)16]4-as crystallographically defined models for the cadmium site. The Cd K-edge extended X-ray absorption fine structure (EXAFS) data, together with the Cd K, LI, LII and LIII near-edge spectra, reveal a predominantly tetrahedral coordination of cadmium by sulfur in both the phytochelatin and synthetic peptide complexes. In particular, the Cd LIII-edge lacks a peak at 3534.9 e V which was found to be prominent for oxygen- or nitrogen-coordinated species. The Cd-S distance in the phytochelatin complex is 2.54 A. The Cd K-edge EXAFS does not show any isolated, well-defined Cd-Cd interactions; however, contrary to the conclusion of previous work, their absence is not necessarily indicative of isolated cadmium-thiolate ligation. Evidence from other studies suggests that high static disorder, combined with a large vibrational component, serve to effectively wash out this contribution to the EXAFS. The sulfur K-edge, moreover, shows a low-energy feature both in the phytochelatin and in the synthetic cadmium-peptide complexes which is consistent with sulfide bound in a cluster with cadmium as found for [S4Cd10(SPh)16]4-. This feature strongly suggests the presence of a polynuclear cadmium cluster in maize phytochelatin.

PMID: 9989220 [PubMed - indexed for MEDLINE]

Vanadium K-edge absorption spectrum of bromoperoxidase from Ascophyllum nodosum.

Hormes J, Kuetgens U, Chauvistre R, Schreiber W, Anders N, Vilter H, Rehder D, Weidemann C.

Physikalisches Institut, Universitat Bonn, F.R.G.

With synchrotron radiation from the Bonn 2.5 GeV synchrotron, high-resolution absorption spectra have been measured at the vanadium K-edge of bromoperoxidase from the marine brown alga Ascophyllum nodosum and several model compounds. The near-edge structure (XANES) of these spectra was used to determine the charge state and the coordination geometry around the vanadium atom. For the active enzyme a coordination charge of 2.7 was found which is compatible with a formal valence of +5, assuming coordination by atoms with a high electronegativity such as oxygen or nitrogen. For the reduced enzyme the coordination charge value of 2.15 indicates the reduction of the valency by 1 unit. Our results suggest that the coordination sphere of the vanadium atom in the native enzyme consists of at least seven oxygen atoms in a distorted octahedral environment with an average bond length of about 2 A. Through the reduction process, the coordination sphere of the vanadium atom changes with a simultaneous decrease of the coordination cage. These results agree with those deduced from previous EPR and 51V-NMR measurements.

PMID: 3167074 [PubMed - indexed for MEDLINE]

Flash-induced 519 nm absorption change in green algae.

Joliot P, Delosme R.

PMID: 4420714 [PubMed - indexed for MEDLINE]

Purification and characterization of hexose oxidase from the red alga Chondrus crispus.

Sullivan JD Jr, Ikawa M.

PMID: 4708670 [PubMed - indexed for MEDLINE]

A thermodynamic analysis of particle flow through biological membranes.

Simons R.

PMID: 5813301 [PubMed - indexed for MEDLINE]

Light-induced rapid absorption changes during photosynthesis. VI. Complex reactions in some blue-green algae.

Ke B, Ngo E.

PMID: 5867545 [PubMed - indexed for MEDLINE]

Effect of Cu and Ni on growth, mineral uptake, photosynthesis and enzyme activities of Chlorella vulgaris at different pH values.

Rai PK, Mallick N, Rai LC.

Laboratory of Algal Biology, Banaras Hindu University, Varanasi, India.

A pH dependent reduction in growth, pigment, ATP content, O2- evolution, carbon fixation, photosynthetic electron transport system, nutrient uptake (NO3- and NH4+), nitrate reductase, and ATPase activities and increase in K+ efflux of Chlorella vulgaris was noticed following supplementation of Cu and Ni to the culture medium. PS II was found to be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) was more sensitive to both pH and metals, the ATPase was however, more sensitive to metals but less sensitive to acidic pH. Acid pH was found to inhibit the nutrient (NO3- and NH4+) uptake and nitrate reductase in a non-competitive manner. The inhibition produced by the test metals alone was of non-competitive type for NO3- uptake, nitrate reductase and ATPase and competitive for NH4+ uptake. Acidity not only inhibited the metabolic variables directly but also through facilitated uptake of metals and increased membrane permeability. A very low sensitivity of ATPase to acidic pH seems to be responsible for the survival of algae in acid environment.

PMID: 8024720 [PubMed - indexed for MEDLINE]

Metal induced inhibition of photosynthesis, photosynthetic electron transport chain and ATP content of Anabaena doliolum and Chlorella vulgaris: interaction with exogenous ATP.

Mallick N, Rai LC.

Laboratory of Algal Biology, Banaras Hindu University, Varanasi, India.

This study demonstrates a concentration dependent inhibition of carbon fixation, O2 evolution, photosynthetic electron transport chain and ATP content of A. doliolum and C. vulgaris by Cu, Ni and Fe. Although the mode of inhibition of photosynthetic electron transport chain of both the algae was similar, PS II depicted greater sensitivity to the test metals used. The toxicity in both organisms was Cu > Ni > Fe. A. doliolum was, however, more sensitive to Cu and Ni, and C. vulgaris to Fe. Toxicity was generally dependent on metal uptake, which in turn was dependent on their concentrations in the external medium. A partial restoration of nutrient uptake, carbon fixation, and enzyme activities following supplementation of exogenous ATP suggests that ATP regulates toxicity through chelation.

PMID: 1449660 [PubMed - indexed for MEDLINE]

Microalgae as bioabsorbents for treating mixture of electroplating and sewage effluent.

Chan SS, Chow H, Wong MH.

Department of Biology, Hong Kong Baptist College, Kowloon.

The effectiveness of copper and nickel uptake by microalgae grown in the mixture of electroplating effluent and sewage was studied. The results showed that a high percentage of copper removal (68.1%-88.2%) was achieved by Chlorella pyrenoidosa (strain No. 26) reared in the mixture of 90% electroplating effluent and 10% raw sewage during the first 3 days despite the fact that cell growth was inhibited. Similar results were also obtained by using Chlorella HKBC-C3, another species collected from one of the heavy metal polluted sites in Hong Kong, isolated and cultured in the Biology Department. There was no significant difference (P greater than 0.05) in the removal of copper and nickel from the effluent between these 2 algal species. However, it was noted that removal of nickel from the mixture by the two species were comparatively lower (less than 20%) than the removal of copper (greater than 68%).

PMID: 1764214 [PubMed - indexed for MEDLINE]

Detoxification effect of iron-encaging zeolite-processed water in tributyltin-intoxicated Euglena gracilis Z.

Ohta M, Nakamura K, Kubo T, Suzuki T.

Department of Marine Bioresources, Faculty of Fisheries, Hokkaido University, Hakodate, Japan.

In our previous paper, we reported the restoration promoting effects of mineral-encaging zeolite-processed water, especially of a Fe-encaging one, on tributyltin chloride (TBTCl)-intoxicated Euglena gracilis. This present study extends the investigation on the behavior of TBTCl and a xenobiotic enzyme, cytochrome P-450, in Euglena cells incubated with or without Fe-encaging zeolite-processed water (FeZW). Subcellular fractionation of TBTCl-intoxicated Euglena cells, atomic absorption spectrophotometry, and GC analyses showed that TBTCl was rapidly incorporated into the cells to halt cell motility. GC-MS showed that FeZW promoted conversion of TBTCl to dibutyltin (DBT) as the major metabolite in the microsomal fraction of the cells. An in vitro incubation system with heat-treated microsomes did not convert TBTCl to DBT. The contribution of cytochrome P-450 in the microsomal fraction was suggested by an immunochemical method. The results suggest that the improvement of detoxification by FeZW in the TBT-intoxicated Euglena cells should be due to activation of biotransformation system of the Euglena cells by FeZW.

PMID: 11272817 [PubMed - indexed for MEDLINE]

Copper and manganese influence the uptake of cadmium in marine macroalgae.

Hall MJ, Brown MT.

Department of Biological Sciences and Plymouth Environmental Research Centre, University of Plymouth, Plymouth, PL4 8AA, United Kingdom.

PMID: 11731831 [PubMed - indexed for MEDLINE]

Incorporation of cadmium by Acetabularia calyculus.

Reyes R, Salazar R, Garcia E.

Simon Bolivar Universidade, Departamento de Biologia de Organismos, Caracas, Venezuela.

PMID: 11911646 [PubMed - indexed for MEDLINE]

Study on the adsorption of vanadium (V) with Scenedesmus obliquus.

Jie N, Zhang Q, Yao G.

College of Basic Science and Technology, China Agricultural University, Beijing, 100094, People's Republic of China.

PMID: 11479674 [PubMed - indexed for MEDLINE]

Bioaccumulation of aluminium in Dunaliella tertiolecta in natural seawater: aluminium-metal (Cu, Pb, Se) interactions and influence of pH.

Turker Sacan M, Balcioglu IA.

Istanbul University Faculty of Science, Department of Biology, 34459 Vezneciler, Istanbul, Turkey.

PMID: 11116317 [PubMed - indexed for MEDLINE]

Macroalgae as biomonitors of heavy metal availability in coastal lagoons from the subtropical Pacific of Mexico.

P inverted question markaez-Osuna F, Ochoa-Izaguirre MJ, Boj inverted question markorquez-Leyva H, Michel-Reynoso IL.

Institute of Marine Sciences and Limnology, Mazatl inverted question markan Station, National Autonomous University of Mexico, Mazatl inverted question markan 82000, Sinaloa, M inverted question markexico.

PMID: 10856342 [PubMed - indexed for MEDLINE]

Production of phytochelatins in the marine diatom Phaeodactylum tricornutum in response to copper and cadmium exposure.

Morelli E, Pratesi E.

Istituto di Biofisica, Via S. Lorenzo, 26, 56127 Pisa, Italy.

PMID: 9307434 [PubMed - indexed for MEDLINE]

Concentrations of selected heavy metals in benthic diatoms and sediment in the Westerschelde estuary.

Absil MC, van Scheppingen Y.

Centre for Estuarine and Coastal Ecology, Netherlands Institute of Ecology, Vierstraat 28, 4401 EA Yerseke, The Netherlands.

PMID: 8661893 [PubMed - indexed for MEDLINE]

Trace metals, PCBs, and PAHs in benthic (epipelic) diatoms from intertidal sediments; a pilot study.

Stronkhorst J, Vos PC, Misdorp R.

National Institute for Marine and Coastal Management, The Hague, The Netherlands.

PMID: 8019075 [PubMed - indexed for MEDLINE]

Accumulation and transfer of copper by Oocystis pusilla.

Chang C, Sibley TH.

School of Fisheries, University of Washington, Seattle 98195.

PMID: 8490274 [PubMed - indexed for MEDLINE]

Cadmium induced potassium efflux from Scenedesmus quadricauda.

Reddy GN, Prasad MN.

School of Life Sciences, University of Hyderabad, India.

PMID: 1421855 [PubMed - indexed for MEDLINE]

High cadmium residues observed during a pilot study in shorebirds and their prey downstream from the El Salvador Copper Mine, Chile.

Vermeer K, Castilla JC.

Canadian Wildlife Service, c/o Institute of Ocean Sciences, Sidney, B.C.

PMID: 2018870 [PubMed - indexed for MEDLINE]

Uptake of lead, chromium, cadmium and cobalt by Cladophora glomerata.

Vymazal J.

Water Research Institute, Department 252, Praha, Czechoslovakia.

PMID: 2328355 [PubMed - indexed for MEDLINE]

Absorption of Cu++ by long-term cultures of Dunaliella salina, D. tertiolecta, and D. viridis.

Lustigman B, Korky J, Zabady A, McCormick JM.

PMID: 4041646 [PubMed - indexed for MEDLINE]

Determination of the absorption of Cr+6 and Cr+3 in an algal culture of Chlorella pyrenoidosa using 51Cr.

Schroll H.

PMID: 749971 [PubMed - indexed for MEDLINE]

Overnight suppression of parathyroid hormone and bone resorption markers by active absorbable algae calcium. A double-blind crossover study.

Fujita T, Ohgitani S, Fujii Y.

Calcium Research Institute, 250 Makamicho, Kishiwada, Osaka 596, Japan.

In order to study the effect of Ca supplementation on the nocturnal rise of PTH and bone resorption, a double-blind, placebo-controlled study was carried out on 9 healthy male volunteers. Regimen A consisted of an oral dose of 150 mg Ca as AAACa after each meal and 450 mg at bedtime; B consisted of 300 mg after each meal and C was placebo. Plasma ionized Ca was significantly higher in A than in B at 6 a.m. the next morning and urinary Ca/Cr after 5 days was higher in A than in B and C. Plasma intact PTH fell by 19 +/- 4 pg/ml in A, 8 +/- 7 in B, and 1 +/- 7 after 1 day, and significantly decreased by 29 +/- 8 in A, increased by 11 +/- 11 in B, and 5 +/- 7 in C after 5 days (A and B, and A and C, p = 0.0242 and 0.0433, respectively), with increases of % tubular reabsorption of phosphorus. Urinary excretion of cross-linked collagen degradation product (Crosslaps) was 40 +/- 10% of the baseline in A, 97 +/- 22 in B, and 173 +/- 30 in C (A and C, P = 0.0061) after 5 days. Systolic blood pressure at 6 a.m. fell by 17 +/- 4 mmHg A, 24 +/- 3 in B, and 4 +/- 2 in C. Highly biologically available AAACa effectively suppressed nocturnal rise of PTH and bone resorption markers in 5 days.

Publication Types:

Clinical Trial

Randomized Controlled Trial

PMID: 9164824 [PubMed - indexed for MEDLINE]

Clinical guidelines for the treatment of osteoporosis in Japan.

Fujita T.

Kobe University, Calcium Research Institute, Kishiwada, Osaka, Japan.

In Japan, unlike in the United States and Europe, where osteoporosis is synonymous with postmenopausal osteoporosis, the need for treatment of osteoporosis has been emphasized only for elderly women with established disease. This may be because women in the immediate postmenopausal period in Japan are virtually free of symptoms such as lumbago and signs such as spinal compression fracture. Osteoporosis typically does not manifest itself until about age 65; therefore, postmenopausal osteoporosis with vertebral fracture below the age of 60 is quite rare in Japan. Unique features of treatment for osteoporosis in Japan include rare use of estrogen replacement therapy, common use of vitamin D derivatives (especially 1alpha(OH) vitamin D) without notable side effects, and use of calcitonin almost exclusively in a low-dose intermittent regimen (20 U/week). Similarly, the use of ipriflavone is common, and calcium supplementation, especially with an active absorbable algae calcium with high bioavailability (AAACa), is effective and popular. The emphasis on the use of calcium, vitamin D, and calcitonin in the treatment of osteoporosis may be explained by an extremely low dietary calcium intake in Japan. Other factors that favor reliance on the calcium-focused approach and avoidance of estrogen include a fatalistic and naturalistic view toward menopause; an uneasiness with hormone replacement therapy; an older female population who seek osteoporosis treatment because of uneventful immediate postmenopausal periods; and the efficient absorption of calcium from the intestine with favorable response to exogenous vitamin D due to a long-standing calcium deficiency and possibly a low incidence of vitamin D-receptor abnormalities.

Publication Types:

Review

Review, Tutorial

PMID: 8974729 [PubMed - indexed for MEDLINE]

Studies on inhibition of intestinal absorption of radioactive strontium. VII. Relationship of biological activity to chemical composition of alginates obtained from North American seaweeds.

Tanaka Y, Waldron-Edward D, Skoryna SC.

PMID: 5673223 [PubMed - indexed for MEDLINE]

Accelerated ion fluxes during differentiation in zoospores of Phytophthora palmivora.

Iser JR, Griffith JM, Balson A, Grant BR.

Russell Grimwade School of Biochemistry, University of Melbourne, Parkville, Victoria, Australia.

Zoospores of Phytophthora palmivora show increased fluxes of Na+ and Ca2+ 3-5 min after they have been stimulated to differentiate with pectin. Both spontaneous and pectin-induced encystment are reduced below pH 6 and accelerated above pH 7. The ionophores monensin and A23187 induce slow differentiation when added together, but not when added separately. Ethanol (0.5%) also induces slow differentiation. Amiloride and verapamil inhibit pectin-induced differentiation and also reduce the onset of the Na+ and Ca2+ flux. A requirement for Ca2+ for differentiation is confirmed, but a requirement for Na+ could not be demonstrated.

PMID: 2496900 [PubMed - indexed for MEDLINE]

Fluorine in the soils of the White Sea Basin and bioindication of pollution.

Evdokimova GA.

Institute of the North Industrial Ecology Problems, Kola Science Centre Russian Academy of Science, Apatity, Murmansk Region. [email protected]

Assessment of the pollution level of soils and vegetation by fluorine and heavy metals and also of the state of the soil microflora in the impact zone of Kandalaksha aluminium factory is discussed. The significant pollution of natural media by fluorine in the basin of the White Sea is established. Concentration of the total fluorine in the organogenic horizon of the Al-Fe-humus podzol soil at a distance of 20 km in the northern direction from the source of emission exceeds the background level by a factor of 3. In the epicentre of emission the amount of total fluorine in the soil exceeds the background level by a factor of 7-8 (Tolerable Amount: 4-5-fold). It is noted that the soil becomes more alkaline under the influence of fluorine and the increased content of chromium along the soil profile exceeds PC by a factor of 3 in the vicinity of the factory. The differences in the dimensions of bacterial and fungi biomass along the gradient of pollution were not revealed in the impact zone. But the changes in the taxonomic structure of fungi and in the level of their domination along the gradient of pollution were estimated. Floristic composition of the soil algae is represented mainly by unicellular green algae with Chlamydomonas elliptica and Bracteacoccus minor predominating.

PMID: 11142915 [PubMed - indexed for MEDLINE]

Electron microscopy study of biosorbents from marine macro alga Durvillaea potatorum.

Yu Q, Kaewsarn P, Van Duong L.

School of Environmental Engineering, Griffith University, Qld, Australia. [email protected]

Biosorbents derived from the biomass of marine algae have shown to have high uptake capacities for heavy metals and the internal structure has been generally assumed to be pseudo-homogenous. In this paper, the microstructures of biosorbents derived from Australian marine alga Durvillaea poratorum were analysed using scanning electron microscopy. The structural components of the biosorbent resembled fiber-like cylinders. The internal structure was a highly connected network of cylinders with varying sizes. Methods of drying and pre-treatment of the biomass also affected the details of the internal structure. Calcium chloride followed by thermal treatment provided the most uniform cylinder networks for the biosorbents. Heavy metal Cu2+ and Cd2+ binding in the biomass was confirmed by using an electron probe microanalyser.

PMID: 10819227 [PubMed - indexed for MEDLINE]

Ionic strength effects in biosorption of metals by marine algae.

Schiewer S, Wong MH.

Department of Biology, Institute for Natural Resources and Waste Management, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, People's Republic of China.

Biosorption, the passive accumulation of metals by biomass, can be used as a cost-effective process for the treatment of metal polluted industrial effluents. The green alga Ulva fascia and the brown seaweeds Sargassum hemiphyllum, Petalonia fascia, and Colpomenia sinuosa were characterized in terms of their number of binding sites, their charge density and intrinsic proton binding constant (pKa) using pH titrations at different ionic strengths. The determined number of binding sites decreased in the order Petalonia > or = Sargassum > Colpomenia > Ulva. Due to their high number of binding sites Sargassum and Petalonia are most promising for biosorption applications. The decrease of proton binding with increasing ionic strength and pH as well as the increase of Cu and Ni binding with increasing pH and decreasing ionic strength could be described by the Donnan model in conjunction with an ion exchange biosorption isotherm.

PMID: 10819211 [PubMed - indexed for MEDLINE]

Performance of different microalgal species in removing nickel and zinc from industrial wastewater.

Chong AM, Wong YS, Tam NF.

Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, People's Republic of China.

A series of batch experiments was conducted to compare the ability of 11 microalgal species of the same cell density in removing nickel (Ni) and zinc (Zn) from synthetic wastewater. These included Chlorella vulgaris (commercially available), Chlorella sorokiniana and Scenedesmus quadricauda (isolates from polluted water of Wuhan, China), and eight different isolates from Hong Kong. The Wuhan isolate of Scenedesmus removed most Ni, probably due to its large biomass. Nickel concentration was reduced from an initial 30 to 0.9 mg/l after 5 min (97% Ni removal), and further declined to 0.4 mg/l after 90 min of treatment. In wastewater containing 30 mg/l Ni and 30 mg/l Zn, more than 98%, Ni and Zn were removed simultaneously at the end of 5 min treatment, indicating that the presence of Zn in wastewater did not affect Ni removal by this Scenedesmus isolate. The second most effective species for Ni removal was an isolate, tentatively identified as Chlorella miniata, Ni concentration was reduced to 10 mg/l after 90 min, and was only slightly interfered by the presence of Zn. In terms of metal removal per unit biomass or unit surface area of algal cells, C. miniata was the best species in removing Ni and Zn. At the other extreme, one Hong Kong isolate (Synechocystis sp.) did not remove any Ni and only achieved 40% Zn removal. Performance of the other isolates was comparable with the commercial C. vulgaris, less than 50% Ni was removed after 5 h of treatment and Ni removal was significantly reduced by the presence of Zn. All algae tested were found to be viable, showing these 11 species could tolerate a mixture of 30 mg/l Ni and 30 mg/l Zn in wastewater.

PMID: 10819208 [PubMed - indexed for MEDLINE]

Physico-chemical characteristics and pollution level of Lake Nainital (U.P., India): role of macrophytes and phytoplankton in biomonitoring and phytoremediation of toxic metal ions.

Ali MB, Tripathi RD, Rai UN, Pal A, Singh SP.

Environmental Botany Laboratory, National Botanical Research Institute, Lucknow, India.

Lake Nainital is the sole source of drinking water for the local people and even to majority of tourists. In background of lake utility and its importance at national level, such study is essential which is focused on toxic metal pollution and current nutrient status of the lake and their magnification by algae and macrophytes. Study has shown that lake water is rich in nutrients which supports growth of many aquatic macrophytes and algal blooms. Besides, water is contaminated with metals like Cr, Cu, Fe, Mn, Ni, Pb and Zn. Concentration of some of them like Fe, Pb and Ni were higher than the recommended maximum permissible limits. Concentration of these metals were also found high in lake sediments. The level of metals amongst various components of lake varied considerably in different season. Plants and algae growing therein accumulated appreciable amount of metals and water roots of Salix being more efficient than others. High metal removing potential of these plants may be significant for biomonitoring studies and could be a useful phytoremediation technology to restore water quality by harvesting submerged and floating biomass inhabiting littoral zone of the lake.

PMID: 10576113 [PubMed - indexed for MEDLINE]

Symmetry breaking in the zygotes of the fucoid algae: controversies and recent progress.

Robinson KR, Wozniak M, Pu R, Messerli M.

Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.

Despite its many advantages as an experimental system for the study of the epigenesis of polarity, it is obvious that the fucoid zygote also presents many problems. The development of polarity proceeds largely independently of direct gene action and thus may be considered a problem in cellular physiology. Ca2+ appears to play an important role in the process, but the optical properties of the zygotes (opacity and autofluorescence) hamper the use of modern methods of visualizing the distribution of Ca2+ and other ions. Likewise, other approaches, such as injection of fluorescent-labeled G-actin, in order to study the dynamics of actin filaments, are subject to the same limitations. It may be that the application of two-photon microscopy will enable experimenters to avoid some of these problems. This technique uses excitation wavelengths that are twice the wavelength of maximum absorption by fluorophores, and sufficient photon density for absorption is achieved only in a thin section. The fucoid zygotes are considerably more transparent to longer wavelengths, so attenuation of the exciting light and autofluorescence should be significantly reduced. Perhaps we will then be able to see further into these opaque cells. Another problem concerns the use of different species and genera. This may be unavoidable; for example, those of us who are land-locked tend to rely on Pelvetia, as it travels and stores better than the various species of Fucus and is less seasonal. Our colleagues fortunate enough to work near the ocean prefer to use the species that are locally available. Nevertheless, it is important to be careful about cross-genus and cross-species generalizations. While it is unlikely, based on what we know, that there are fundamental differences in physiological mechanisms among species, there may be small but still important differences in details. Obviously, investigators should directly compare results in more than one species whenever possible. The area of greatest disagreement, perhaps, concerns the mechanism of polarity formation, as opposed to its overt manifestation, germination. Are Ca2+ and actin involved or not? Assuming Ca2+ is involved, is the source internal or external? One basis for the different findings may be the differences in the strength of the polarizing signal provided to the zygotes. Clearly, the cells have powerful mechanisms for amplifying a faint asymmetry and developing an axis in response to an external signal. Furthermore, the fucoids generally develop in the intertidal zone and thus must be adapted to meeting the challenge of a widely varying external environment. They may have alternate mechanisms for responding to unilateral light. We have adopted the approach of presenting the cells with a fairly weak light signal--the minimum required to induce a considerable degree of organization of a population of zygotes. We then determine the effects of various inhibitors on photopolarization. One advantage of this approach is that it has allowed us to find treatments that increase the sensitivity of the zygotes to light, something that would not be possible if the untreated controls were fully polarized. Some of the differences between our results and those of others may be related to their use of a stronger light stimulus. It may be that if given a strong stimulus, a sufficient trace is left in the cells so that they can organize an axis when an inhibitor is removed. Careful consideration of this point may help to reconcile apparently contradictory findings. Despite these difficulties, the fucoid zygotes are likely to continue to be an important experimental system. Technology, including the development of more specific inhibitory reagents, may allow some of the shortcomings of the system to be overcome, and careful consideration of experimental conditions may resolve some of the points of disagreement.

Publication Types:

Review

Review, Tutorial

PMID: 9891878 [PubMed - indexed for MEDLINE]

Light intensity influences chromium bioaccumulation and toxicity in Scenedesmus acutus (Chlorophyceae).

Gorbi G, Corradi MG, Invidia M, Bassi M.

Department of Environmental Sciences, University of Parma, Parma, I-43100, Italy.

The influence of light intensity on chromium uptake was studied in two strains of the freshwater unicellular alga Scenedesmus acutus (Chlorophyceae) having different sensitivity to Cr poisoning and light intensity. The two strains were subjected to different Cr treatments at 3000 and 80 lux. Cr toxicity was assessed by algal growth rate, recovery test, methylene blue staining, and determination of photosynthetic activity. After 2 and 4 days of treatment, bioaccumulated chromium, cell dry mass, and protein and carbohydrate contents were also assessed. When the algae were treated at 3000 lux, different bioaccumulation patterns were obtained when Cr content was related to dry mass, cell number, or protein content. A direct relationship between Cr content and cell mortality was observed only when the amount of Cr was related to protein content. In both strains Cr uptake was slower in subdued light, suggesting that it is linked to energy-dependent processes. The difference between the strains in sensitivity to Cr poisoning was also evident in subdued light.

PMID: 11161675 [PubMed - indexed for MEDLINE]

Monitoring of labile zinc in cultures of Skeletonema costatum using a salt groundwater.

Schintu M, Koussih L, Chevolot L, Amiard JC, Robert JM.

Dipartimento di Igiene e Sanita Pubblica, Universita di Cagliari, Via Porcell 4, Cagliari, 09100, Italy.

Labile Zn concentration was monitored by differential pulse anodic stripping voltammetry (DPASV) throughout the exponential growth phase of the marine diatom Skeletonema costatum (Grev.) Cleve. Algal blooms were induced both under natural conditions and in laboratory experiments using a salt groundwater (salinity 33) from the Bay of Bourgneuf, northwest coast of France. Salt groundwater is a very complex medium containing high concentrations of dissolved organic matter and other trace metal adsorbents, such as phosphate, iron oxyhydroxides, and manganese and silicon oxides, which can bind metal ions, reducing their availability and toxicity to algae. Besides metal uptake by algae and complexation of Zn by algal exudates, the rapid decrease in the labile Zn concentration during the algal blooms was ascribed mainly to the adsorption or coprecipitation of Zn ion onto freshly formed iron hydroxides. Copyright 1999 Academic Press.

PMID: 10090809 [PubMed - indexed for MEDLINE]

[Determination of harmful metals in food (XII). Analysis of copper, cadmium and lead in algae and shells with anodic stripping voltammetry and atomic absorption spectrometry]

[Article in Japanese]

Tatsuno T, Suzuki T, Uchiyama M.

PMID: 6675759 [PubMed - indexed for MEDLINE]

Healthy environments for healthy people: bioremediation today and tomorrow.

Bonaventura C, Johnson FM.

Marine Biomedical Center, Duke Univesity Nicholas School, Environment Marine Laboratory, Beaufort, North Carolina 28516-9701, USA. [email protected]

Increases in environmental contamination lead to a progressive deterioration of environmental quality. This condition challenges our global society to find effective measures of remediation to reverse the negative conditions that severely threaten human and environmental health. We discuss the progress being made toward this goal through application of bioremediation techniques. Bioremediation generally utilizes microbes (bacteria, fungi, yeast, and algae), although higher plants are used in some applications. New bioremediation approaches are emerging based on advances in molecular biology and process engineering. Bioremediation continues to be the favored approach for processing biological wastes and avoiding microbial pathogenesis. Bioremediation may also play an increasing role in concentrating metals and radioactive materials to avoid toxicity or to recover metals for reuse. Microbes can biodegrade organic chemicals; purposeful enhancement of this natural process can aid in pollutant degradation and waste-site cleanup operations. Recently developed rapid-screening assays can identify organisms capable of degrading specific wastes and new gene-probe methods can ascertain their abundance at specific sites. New tools and techniques for use of bioremediation in situ, in biofilters, and in bioreactors are contributing to the rapid growth of this field. Bioremediation has already proven itself to be a cost-effective and beneficial addition to chemical and physical methods of managing wastes and environmental pollutants. We anticipate that it will play an increasingly important role as a result of new and emerging techniques and processes.

Publication Types:

Review

Review, Academic

PMID: 9114274 [PubMed - indexed for MEDLINE]

Trace metal concentrations in marine macroalgae from different biotopes in the Aegean Sea.

Sawidis T, Brown MT, Zachariadis G, Sratis I.

Department of Botany, University of Thessaloniki, Greece.

The commonest species of red, brown, and green macroalgae were sampled from a range of biotopes in the Aegean Sea and analysed for five different trace metals. Significant differences in metal concentrations were found among different seaweed species from the same biotope. The concentrations of metals in the various seaweed species may reflect their morphology, with those having a larger surface area having a greater internal content. Different species of seaweed have different affinities for different heavy metals. This may reflect competition between metals for binding or uptake sites in the seaweed. Comparing metal concentrations in algae among the studied sampling stations clearly indicates that the degree of accumulation depends not only on human activities but also on the geology of the specific area. While seaweed can be used successfully to assess the levels of heavy metals in the marine environment, not all elevated concentrations of heavy metals necessarily reflect increased levels of pollution. Indeed, the high concentrations of certain metals, e.g., Ni, found in our seaweed samples reflected the metaliferrous nature of the rock. It is therefore important to take account of a region's geology before attempting to interpret the data.

PMID: 11488389 [PubMed - indexed for MEDLINE]

Heavy metals in the aquatic environment of the Southern Adriatic Sea, Italy: macroalgae, sediments and benthic species.

Storelli MM, Storelli A, Marcotrigiano GO.

Pharmacal-Biologic Department, Medicine Veterinary Faculty, University of Bari, Valenzano, Italy.

Samples of sea urchins (Paracentrotus lividus), holothurians (Holothuria polii), green algae (Ulva lactuca. Codium vermilara and Enteromorpha prolifera) and sediments were collected from different coastal zones of the South Adriatic Sea (Italy). The occurrence of metals in macroalgae is poor especially if compared with that reported in other coastal areas affected by human activities, with the exception of Fe that showed high mean values (405 microg g(-1) dry wt.). Likewise, relationships between metal concentrations in holothurians and sediments were found, demonstrating that H. polii could serve as bioindicator for Hg and Cu.

PMID: 11485218 [PubMed - indexed for MEDLINE]

Lead and zinc in sediments and biota from Maarmorilik, West Greenland: an assessment of the environmental impact of mining wastes on an Arctic fjord system.

Larsen TS, Kristensen JA, Asmund G, Bjerregaard P.

Institute of Biology, Odense University, Denmark.

Lead and zinc levels in sediments and biota from the fjord system surrounding the lead/zinc mine at Maarmorilik, West Greenland, were investigated to evaluate the impact of waste rock and marine-deposited tailings on the marine biota. Concentrations of metal in the sediment were up to 8,922 +/- 622 microg g(-1) (dry wt.) for lead and 19,351+/- 476 microg g(-1) (dry wt.) for zinc. Levels of lead and zinc were also elevated in a suite of monitor organisms. The feeding modes of the organisms were used to explain the sources of metals to the organisms. After closure of the mine, the concentrations of metals in the upper centimetres of the sediments decreased, and a decreased impact of metals on the brown alga Fucus distichus was observed. However, the metals in the sediments still affect the marine biota in the area.

PMID: 11504350 [PubMed - indexed for MEDLINE]

Elemental concentrations in different species of seaweeds from Loreto Bay, Baja California Sur, Mexico: implications for the geochemical control of metals in algal tissue.

Sanchez-Rodriguez I, Huerta-Diaz MA, Choumiline E, Holguin-Quinones O, Zertuche-Gonzalez JA.

Centro Interdisciplinario de Ciencias Marinas, CICIM AR-IPN, La Paz, BCS, Mexico.

Concentration levels of 21 elements were analyzed by instrumental neutron activation analysis (Rb, Cs, Ca, Sr, Ba, Sc, Cr, Fe, Co, Ni, Zn, Se, As, Sb, Th, U, Br, Hf, Ta, Zr, and Ag) in seven different seaweed species (Codium cuneatum, Sargassum sinicola, Padina durvillaei, Laurencia johnstonii, L. papillosa, Gracilaria pachidermatica and Hypnea pannosa), collected in a shallow coastal zone from Bahia de Loreto, Baja California Sur, Mexico. Measured concentrations in algal tissue spanned almost eight orders of magnitude (from 2.0 x 10(-3) microg g(-1) for Hf to 1.2 x 10(5) microg g(-1) for Ca). Ca was consistently the most abundant element in all analyzed seaweeds, followed by Fe and Sr. Brown algae showed a tendency to incorporate higher concentrations of elements than red and green algae. Additionally, there were significant linear correlations (P < 0.05 to P < 0.001) between a total of 76 different pairs of elements, some of them (e.g. Rb-Ni, Rb-Ag, Sc Cr, Sc-Fe, Sc Ni, Sc Hf, Cr Fe, Fe Ni, Fe-Hf and Ni-Th) highly correlated (r2 > 0.900). A significant correlation (r2 = 0.701, n = 18, P < 0.001) exists between our measurements in the tissue of algae and their corresponding average elemental concentrations in oceanic water from the North Pacific Ocean. Hence, overall elemental abundance in algal tissue apparently is controlled by the elemental abundance in oceanic water, whereas metabolic processes as well as environmental factors relevant to each region modify the final concentration of a given element in the body of a macroalgae.

PMID: 11504337 [PubMed - indexed for MEDLINE]

Repeated use of two Chlorella species, C. vulgaris and WW1 for cyclic nickel biosorption.

Tam NF, Wong JP, Wong YS.

Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong. [email protected]

Two living Chlorella species were used to remove nickel from solution containing 30 micrograms Ni ml-1 in 10 successive cycles. The present study also examined the continued viability of these two algal species after repeated exposure to nickel. The two species of Chlorella were Chlorella vulgaris (commercially available) and WW1 (indigenous species isolated from domestic sewage and was tentatively identified as Chlorella miniata). The nickel removal percentage of WW1 cells was maintained at around 85% in the first five cycles, then declined slightly from the fifth cycle onwards, and finally achieved around 70% removal at the end of the 10th cycle. On the contrary, the removal efficiency of C. vulgaris declined from 50 to 30% during the 10 cycles of nickel bisorption. At the end of these 10 successive cycles, WW1 accumulated a substantial amount of Ni2+ (the cumulative cellular Ni concentration was 0.92% dry w.), while the value was only 0.17% in the case of C. vulgaris. These results suggest that the local isolate, WW1, had more consistent and satisfactory ability for removing Ni than the commercial C. vulgaris. Both algal species were still capable of dividing after each nickel treatment cycle, suggesting that the cells were not killed even when significant amounts of nickel were adsorbed/absorbed. However, Ni exposure adversely affected the physiological activity of algal cells as reflected by the decline in division rate and chlorophyll-a activity in both species. Such negative effects became more obvious as the number of cyclic treatments was increased. Nevertheless, WW1 cells appeared to recover from nickel treatment when re-cultivated in commercial medium for 2 weeks.

PMID: 11444009 [PubMed - indexed for MEDLINE]

Cadmium(II) removal from aqueous solutions by pre-treated biomass of marine alga Padina sp.

Kaewsarn P, Yu Q.

School of Environmental Engineering, Nathan Campus, Griffith University, Queensland, 4111 Australia.

In this study, the adsorption properties of a pre-treated biomass from marine alga Padina sp., a biomass collected from Surin Island, Thailand, for removal of cadmium(II) ions from aqueous solutions was investigated. Batch and column experiments were conducted to determine the adsorption properties of the modified biomass. At a pH of 5, the maximum removal capacity of the biomass is 0.53 mmol/g. The kinetics of cadmium(II) adsorption were fast with 90% of adsorption taking place within 35 min. This study demonstrated that the pre-treated biomass of Padina sp. could be used as an efficient biosorbent for the treatment of cadmium(II)-bearing wastewater streams.

PMID: 11234537 [PubMed - indexed for MEDLINE]

Effects of development time, biomass and ferromanganese oxides on nickel sorption by stream periphyton.

Gray BR, Hill WR, Stewart AJ.

Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6351, USA. [email protected]

Procedurally defined periphyton frequently includes substantial quantities of hydrous iron (Fe) and manganese (Mn) oxides. As these oxides are strong sorbers of heavy metals, their presence may complicate estimation of metal bioaccumulation by periphyton. We examined the relationship between nickel (Ni) sorption and the development time, biomass, and Fe and Mn oxide content of stream periphyton. Development time, the time during which periphyton accrued on submerged tile substrata, was used to provide variation in biomass, Fe and Mn levels. Stream periphyton from four development times was exposed to Ni for 2 h in the laboratory, and then ashed. Development time was significantly associated with ash-free dry mass (AFDM), Fe and Mn levels (ANOVA, P < or = 0.003). Ni extracted by a mild reductant (hydroxylamine hydrochloride) was significantly associated with development time, and with AFDM, Fe and Mn levels (linear models, P < or = 0.0002). A subsequent acid digestion yielded similar associations with the same variables (linear models, P < or = 0.0001). For both extractions, AFDM was significantly and positively correlated with Fe (r = 0.68 and 0.89) and with Mn (r = 0.77 and 0.93) (Spearman rank, P < or = 0.005). These data demonstrate the importance of periphyton development time in influencing both metal sorption and levels of biomass and ferromanganese oxides. The data also suggest that metal contaminant levels in periphyton should not be attributed automatically to biotic sorption. Periphyton metal-accumulation studies conducted where ferromanganese oxide concentrations are elevated should address the potential metal-sorbing roles of Fe and Mn oxides within the periphyton matrix.

PMID: 11202655 [PubMed - indexed for MEDLINE]

Effects of major nutrient additions on metal uptake in phytoplankton.

Wang WX, Dei RC.

Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, People's Republic of China. [email protected]

We examined the influences of major nutrients (N, P, Si) on the accumulation of three trace metals [Cd, Se(IV), and Zn] in four species of marine phytoplankton (diatom, green alga, dinoflagellate, prasinophyte). Relative metal uptake was quantified by the kinetic measurements of metal concentration factor over a short exposure period. Our study demonstrated that nutrient addition significantly influenced the metal uptake rate and the cell growth rate in all four phytoplankton species. An increase in ambient N concentration considerably enhanced metal uptake by the cells. The dry weight concentration factor increased by 2.4-14.9 times for Cd, 1.1-4.0 times for Se, and 1.1-5.4 times for Zn in all four phytoplankton species with an addition of 176.4 microM N. The effects of P or Si addition on metal uptake and cell growth were less pronounced than the effects of N addition. Under most circumstances the rate of metal uptake increased exponentially with increasing cell growth rate constant. Only Se(IV) uptake in the diatom Phaeodactylum tricornutum was not correlated with cell growth rate. Se(IV) was not accumulated by the green algae Chlorella autotrophica at a high P concentration (7.2 microM), but appreciable accumulation was documented in cells inoculated without P addition. Our study therefore demonstrated that nutrient enrichments in many coastal waters can considerably affect trace metal uptake in phytoplankton and presumably metal trophic transfer in marine food chains.

PMID: 11202726 [PubMed - indexed for MEDLINE]

Biosorption of trivalent chromium on the brown seaweed biomass.

Yun YS, Park D, Park JM, Volesky B.

Department of Chemical Engineering, School of Environmental Science and Engineering, Pohang University of Science and Technology, Hyoja-dong, Korea.

Biosorption has attracted attention as a cost-effective means for the treatment of metal-bearing wastewater. However, the mechanism of metal binding is not clearly understood, and consequently, modeling of the biosorption performance is still raising debates. In this study, the biosorption of trivalent chromium was investigated with protonated brown alga Ecklonia biomass as a model system. Titration of the biomass revealed that it contains at least three types of functional groups. The Fourier transform infrared spectrometry showed that the carboxyl group was the chromium-binding site within the pH range (pH 1-5) used in this study, where chromium does not precipitate. The pK value and the number of carboxyl groups were estimated to be 4.6 +/- 0.1 and 2.2 +/- 0.1 mmol/g, respectively. The equilibrium sorption isotherms determined at different solution pH indicated that the uptake of chromium increased significantly with increasing pH. A model for the description of chromium biosorption was developed incorporating the hydrolysis reactions that chromium undergoes in the aquatic phase. The model was able to predict the equilibrium sorption experimental data at different pH values and chromium concentrations. In addition, the speciation of the binding site as a function of the solution pH was predicted using the model in order to visualize the distribution of chromium ionic species on the binding site.

PMID: 11718356 [PubMed - indexed for MEDLINE]

Comparative analysis of the biosorption of cadmium, lead, nickel, and zinc by algae.

Klimmek S, Stan HJ, Wilke A, Bunke G, Buchholz R.

Institute of Food Chemistry, Technical University Berlin, Germany.

Thirty strains of algae were examined for their biosorption abilities in the uptake of cadmium, lead, nickel, and zinc from aqueous solution. A wide range of adsorption capacities between the different strains of algae and between the four metals can be observed. The cyanophyceae Lyngbya taylorii exhibited high uptake capacities for the four metals. The algae showed maximum capacities according to the Langmuir Adsorption Model of 1.47 mmol lead, 0.37 mmol cadmium, 0.65 mmol nickel, and 0.49 mmol zinc per gram of dry biomass. The optimum pH for L. taylorii was between pH 3 and 7 for lead, cadmium, and zinc and between pH 4 and 7 for nickel. Studies with the algae indicated a preference for the uptake of lead over cadmium, nickel, and zinc in a four metal solution. The metal binding abilities of L. taylorii could be improved by phosphorylation of the biomass. The modified biosorbent demonstrated maximum capacities of 2.52 mmol cadmium, 3.08 mmol lead, 2.79 mmol nickel, and 2.60 mmol zinc per gram of dry biomass. Investigations with phosphated L. taylorii indicated high capacities for the four metals also at low pH. The selectivity remained quite similar to the unmodified algae.

PMID: 11718343 [PubMed - indexed for MEDLINE]

The effects of pH and surface composition on Pb adsorption to natural freshwater biofilms.

Wilson AR, Lion LW, Nelson YM, Shuler ML, Ghiorse WC.

School of Civil and Environmental Engineering, Cornell University, Ithaca, New York 14853, USA.

Two dominant variables that control the adsorption of toxic trace metals to suspended particulate materials and aquatic surface coatings are surface composition and solution pH. A model for the pH-dependent adsorption of Pbto heterogeneous particulate surface mixtures was derived from experimental evaluation of Pb adsorption to laboratory-derived surrogates. The surrogate materials were selected to represent natural reactive surface components. Pb adsorption to both the laboratory surrogates and natural biofilms was determined in chemically defined solutions under controlled laboratory conditions. Pb adsorption was measured over a pH range of 5-8, with an initial Pb concentration in solution of 2.0 microM. The surface components considered include amorphous Fe oxide, biogenic Mn oxide produced by a Mn(II) oxidizing bacterium (Leptothrix discophora SS-1), Al oxide, the common green alga Chlorella vulgaris, and Leptothrix discophora SS-1 cells. A linearization of Pb adsorption data for each adsorbent was used to quantify the relationship between Pb adsorption and pH. The parameters for individual adsorbents were incorporated into an additive model to predict the total Pb adsorption in multiple-adsorbent natural surface coatings that were collected from Cayuga Lake, NY. Pb adsorption experiments on the natural surface coatings at variable pH were utilized to verify the additive model predictions based on the pH dependent behavior of the experimental laboratory surrogates. Observed Pb adsorption is consistent with the model predictions (within 1-24%) over the range of solution pH values considered. The experimental results indicate that the combination of Fe and biogenic Mn oxides can contribute as much as 90% of Pb adsorbed on Cayuga Lake biofilms, with the dominant adsorbent switching from Mn to Fe oxide with increasing pH.

PMID: 11505999 [PubMed - indexed for MEDLINE]

Study of the mechanisms of cadmium biosorption by dealginated seaweed waste.

Romero-Gonzalez ME, Williams CJ, Gardiner PH.

Division of Chemistry, School of Science and Mathematics, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, U.K.

The ability of dealginated seaweed waste, a waste material derived from the commercial processing of seaweed for alginate production, to remove cadmium from solution was determined. Cadmium sorption was found to be rapid (91% removal within 5 min), achieving a residual concentration of 0.8 mg L-1 after 1-h contact time from an initial solution concentration of 10 mg L-1. The binding of cadmium by dealginate was found to be pH dependent, optimal sorption occurring at around pH 6-8. The mechanism of cadmium ion binding by dealginate was investigated by a number of techniques. Potentiometric titration of the dealginate revealed two distinct pKa values, the first having a value similar to carboxyl groups and the second comparable with that of saturated thiols and amines. Esterification of the dealginate resulted in the subsequent reduction in cadmium sorption (95% to 17%), indicating that carboxyl groups are largely responsible for sorption. Evidence from FT-IR spectra confirmed the presence of carboxyl groups in untreated dealginate, while the number of carboxyl groups was markedly reduced in the esterified sample. Furthermore, the FT-IR spectrum for dealginate was found to be similar to that previously reported for mannuronic acid-rich calcium alginate. Determination of a molar ratio in the displacement of calcium by cadmium on dealginate further supported the presence of an ion-exchange relationship. The ion-exchange constant was calculated to be 0.329 x 10(-6). The speciation of cadmium in solution both before and after sorption was determined by an ion-selective electrode (ISE) technique. The findings of this study suggest that the sorption of cadmium by dealginate is mainly due to an ion-exchange mechanism.

PMID: 11478258 [PubMed - indexed for MEDLINE]

Erratum in:

Environ Sci Technol 2001 Oct 1;35(19):4000

Thiosulfate enhances silver uptake by a green alga: role of anion transporters in metal uptake.

Fortin C, Campbell PG.

INRS-Eau, Universite du Quebec, C.P. 7500, Sainte-Foy, Quebec, Canada, G1V 4C7.

Short-term (< 1 h) silver uptake by the green alga Chlamydomonas reinhardtii was measured in the laboratory in defined inorganic media in the presence or absence of ligands (chloride and thiosulfate). In contradiction to the free-ion model of metal uptake, silver accumulation by the alga proved to be sensitive to the choice of ligand used to buffer the free silver concentration. For a low fixed free Ag+ concentration of 10 nM, silver uptake in the presence of thiosulfate (0.11 microM) was 2x greater than in the presence of chloride (4 mM). When sulfate was removed from the exposure medium (i.e., 81 microM-->0 microM), silver uptake in the presence of thiosulfate was even more markedly enhanced (more than 4x greater than in the presence of chloride). Varying the sulfate concentration in the exposure medium only affected silver uptake if thiosulfate was present. We conclude that silver-thiosulfate complexes are transported across the plasma membrane via sulfate/thiosulfate transport systems and that sulfate acts as a competitive inhibitor of this uptake mechanism.

PMID: 11414021 [PubMed - indexed for MEDLINE]

Biosorption and desorption of cadmium(II) by biomass of Laminaria japonica.

Yin P, Yu Q, Lin Z, Kaewsarn P.

Department of Chemistry, Jinan University, Guangzhou 51063, P.R. China.

Biosorption and desorption properties of cadmium(II) from aqueous solutions by the biomass of marine alga Laminaria japonica were investigated. Results indicated that the uptake capacities were solution pH dependent and a maximum uptake capacity of about 1.3 mmol g-1 (dry weight) was observed at pH 6. The adsorbed cadmium cannot be desorbed by distilled water, but it can be effectively recovered by using acidic or EDTA solutions. The equilibrium isotherms can be described well with the Langmuir adsorption equation. Biomass, pre-treated with calcium solution exhibited a higher (about 30%) uptake capacity and can be easily settled from aqueous solutions. Batch kinetics experiments indicated that more than 90% of the adsorption occurred within 20 minutes of agitation and equilibrium was reached within one hour. Fixed-bed experiments showed similar uptake capacities to those of batch results and sharp breakthrough curves were obtained. This study indicated that the biomass of L. japonica can be used as an efficient biosorbent for the removal and recovery of cadmium(II) from waste water streams.

PMID: 11424727 [PubMed - indexed for MEDLINE]

Influence of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid pH buffer on the biological response of marine algae.

Vasconcelos MT, Leal MF.

LAQUIPAI, Chemistry Department, Faculty of Science, University of Porto, Portugal. [email protected]

The N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) is extensively used as pH buffer in culture media for testing chemicals. However, this study demonstrates that 0.01 M HEPES significantly reduces the rate of Cu, Pb, and Cd binding to Porphyra spp. and Enteromorpha spp. marine macroalgae. The HEPES also decreased the accumulation of Cu, Pb, and Cd but not Hg by these macroalgae. Both the extracellular adsorption and the intracellular uptake of the metals were influenced by HEPES to a similar extent. The HEPES also promoted the release of exudates by the algae, and these exudates form very stable complexes with Cu (and probably with other trace metal ions). The HEPES interference varied with the nature of the metal, the macroalga, and the season. The presence of 0.01 M HEPES in seawater cultures of the Emiliania huxleyi (a microalga) also interfered with E. huxleyi growth, liberation of Cu-complexing organic ligands, and Cu uptake. The HEPES, which displays surface activity, may facilitate the binding of metals to the algae for an initial exposure period. The metal taken up appears to stimulate the liberation of exudates that subsequently control the bioavailability of the metals and therefore metal uptake. Because HEPES can control the uptake of trace metals by algae and the production of organic ligands, the results obtained in cultures containing the HEPES pH buffer can be influenced by this component of the media.

PMID: 11837230 [PubMed - indexed for MEDLINE]

Relationship between feeding-induced ventilatory activity and bioaccumulation of dissolved and algal-bound cadmium in the Asiatic clam Corbicula fluminea.

Tran D, Boudou A, Massabuau JC.

UMR 5805, Laboratoire d'Ecophysiologie et Ecotoxicologie des Systemes Aquatiques, Universite Bordeaux I and CNRS, Arcachon, France.

The influence of feeding-induced ventilatory adaptation on cadmium accumulation patterns was analyzed in quiescent Asiatic clam Corbicula fluminea studied in steady-state conditions at 15 degrees C and 25 degrees C and in air-equilibrated water. Ventilatory activity, algae inflow rate, amounts of inspired dissolved and algae-bound Cd, and whole-body and tissue-specific metal concentrations were studied during a 15-d exposure period at a low dissolved cadmium concentration of 2 microg/L and various algal concentrations of Scenedesmus subspicatus. Great care was taken not to externally stimulate animals. Four main results were obtained as regard to regulation of ventilatory activity and metal accumulation rate. First, at 25 degrees C, feeding purposes strongly stimulated ventilatory activity, while at 15 degrees C, it was independent of it except at 1 to 2 x 10(5) algae/ml. Second, Cd accumulation rate increased at higher temperature. Third, accumulation rate exhibited a positive correlation with the ventilatory flow rate. Fourth, no correlation was observed with the quantity of ventilated algae-bound Cd but, rather, with the quantity of ventilated dissolved Cd. It is concluded that the physiology of the animals can be fundamental in affecting metal accumulation process.

PMID: 11833801 [PubMed - indexed for MEDLINE]

Linking ecological impact to metal concentrations and speciation: a microcosm experiment using a salt marsh meiofaunal community.

Millward RN, Carman KR, Fleeger JW, Gambrell RP, Powell RT, Rouse MA.

Biological Sciences, Louisiana State University, Baton Rouge 70803, USA.

Microcosm experiments addressed the impact of a mixture of Cu, Cr, Cd, Pb, and Hg at three concentrations after 36 h, 12 d, and 30 d on a meiofauna-dominated salt marsh community. In addition to analyzing effects on meiofaunal abundances, the study quantified the sediment metal concentrations of all five metals and pore-water concentrations, speciation, and ligand complexation of Cu. Abundances of deposit feeders such as the polychaete Streblospio benedicti, gastropods, and bivalves were impacted at lower metal concentrations than the mainly algal-feeding copepods, ostracods, and nematodes. We suggest that this might be due to bulk ingestion of metal-contaminated sediments resulting in relatively higher metal exposure in the deposit feeders than in the other, nondeposit feeding taxa. Copepod and ostracod abundances decreased only in the highest metal treatment, where levels of inorganic Cu ([Cu']) in pore waters were similar to levels associated with both acute and subacute toxicity in published in vivo toxicity studies of marine copepods. The higher metal treatments yielded disproportionately higher pore-water [Cu] compared with sediment [Cu], suggesting saturation of sediment-associated ligands with increased additions of Cu. Similarly, the higher metal treatments appeared to reach saturation of the organic Cu ligands, with the excess pore-water [Cu] present in the more toxic, inorganic species of Cu. Acid-volatile sulfide (AVS) concentrations at sediment horizons inhabited by meiofauna were low and AVS was not considered a significant metal ligand at these depths. Since meiofauna are predominantly associated with oxic surface sediments, it is doubtful that AVS is a major factor controlling availability of free metal for exposure to these taxa.

PMID: 11521831 [PubMed - indexed for MEDLINE]

Sublethal effects of silver in zooplankton: importance of exposure pathways and implications for toxicity testing.

Hook SE, Fisher NS.

Marine Sciences Research Center, State University of New York, Stony Brook 11794-5000, USA.

In aquatic environments, organisms are exposed to contaminants via direct uptake from water and by trophic transfer. However, most toxicity tests only examine uptake via the dissolved phase. We compared the response of marine and freshwater crustacean zooplankton to silver following dissolved and food exposure. Silver, like other metals, concentrates in aquatic food chains and may exert toxicity. In standard solute exposure toxicity tests, Ag is toxic to zooplankton at concentrations of 400 nM for marine copepods and 100 nM for freshwater cladocerans, concentrations far greater than those in most waters. However, if Ag is accumulated from algal food, reproductive success decreases by >50% when algae are exposed to only 1 nM Ag in copepods and 0.5 nM Ag in cladocerans. These concentrations are within an order of magnitude of those found in contaminated estuaries. Following dietary exposure, decreased egg production and viability occur when tissue Ag concentrations increase three- to fourfold to 0.3 ppm in cladocerans and 0.5 ppm in copepods. Assimilated Ag depresses egg production by reducing yolk protein deposition and ovarian development. Our results indicate that ecologically relevant toxicity tests should consider sublethal effects of contaminants obtained from food since these effects cannot be predicted from exposures to only dissolved contaminants.

PMID: 11349858 [PubMed - indexed for MEDLINE]

Characterization of hexose oxidase from the red seaweed Chondrus crispus.

Groen BW, De Vries S, Duine JA.

Department of Microbiology and Enzymology, Delft University of Technology, The Netherlands.

Hexose oxidase from the red seaweed, Chondrus crispus was purified to homogeneity. The enzyme appeared to be encapsulated in particles obtained after mechanical disintegration of the fronds. Liberation of the enzyme in soluble form required either waiting for the spontaneous development of a suitable microbial flora in the suspension, or treatment with a mixture of proteases (pronase). As deduced from (SDS/)PAGE, the enzyme has a molecular mass of 87 kDa and probably consists of subunits of 36 kDa and 25 kDa. The low isoelectric point of 2.8 and the presence of 25% (by mass) sugars indicate that the enzyme is a strongly acidic glycoprotein. The absorption spectrum of isolated enzyme minus that of the substrate-reduced enzyme, and the EPR spectrum of the free radical observed in the reduced enzyme revealed the presence of a flavin. This cofactor is probably covalently bound since flavins were not released upon denaturation of the enzyme by heat or acid treatment. Taking free FAD as a reference compound, the enzyme contains 1 mol flavin/mol enzyme. EPR spectroscopy of the purified preparation showed the presence of Cu2+. However, since the amount was substoichiometric, substrate addition did not affect the signal, and the addition of chelator or Cu2+ did not affect the activity, the presence of this metal ion seems adventitious. It is concluded that the large discrepancies between the presently and the previously reported [Sullivan, J. D. & Ikawa, M. (1973) Biochim. Biophys. Acta 309, 11-22] characteristics of the enzyme probably originate from the characterization of a contaminating protein in the latter case.

PMID: 9108257 [PubMed - indexed for MEDLINE]

Induction, localization and metal content of hydrogenase in the green alga Chlamydomonas reinhardtii.

Happe T, Mosler B, Naber JD.

Ruhr-Universitat Bochum, Lehrstuhl fur Biochemie der Pflanzen, Germany.

The hydrogenase enzyme occurring in Chlamydomonas reinhardtii is induced by anaerobic adaptation of the cells. In aerobically growing cells, antibodies against the hydrogenase failed to detect either active or inactive enzyme. However, already 10 min after the onset of anaerobic adaptation, the protein could be detected. The maximal amount of enzyme was reached after 2-3 hours anaerobiosis. Addition of nickel or iron to the growth medium did not influence activity. In atomic absorption experiments, a Ni/Fe ratio of about 1:250 was measured. We, therefore, propose the hydrogenase from C. reinhardtii to be of the Fe-only type. Adaptation in the presence of uncouplers of phosphorylation showed this process to be energy-dependent. From protein synthesis inhibition experiments, it is concluded that the protein is synthesized on cytoplasmic ribosomes and, therefore, must be nuclear encoded. After isolation of intact chloroplasts from adapted cells, the active enzyme was shown, by Western-blotting analysis, to be located in the chloroplasts.

PMID: 8026490 [PubMed - indexed for MEDLINE]

Ferredoxin from a red alga, Porphyra umbilicalis.

Andrew PW, Rogers LJ, Boulter D, Haslett BG.

A plant-algal type ferredoxin was isolated from the red alga, Porphyra umbilicalis. In its oxidised form the ferredoxin had absorption maxima at 277, (281), 323, 420 and 462 nm. Two atoms each of non-haem iron and labile sulphur were present per molecule protein. The midpoint potential of the protein was -400 mV and it effectively mediated electron transport in the NADP-photoreduction system of barley. The amino acid composition of Porphyra umbilicalis ferredoxin was determined as (Lys4, His2, Arg1, Asx10, Thr8, Ser7, Glx16-17, Pro3, Gly7, Ala8, Cys5, Val6, Met1, Ile5, Leu8, Tyr5, Phe2). The minimum molecular weight of approximately 11000 was confirmed by sedimentation-equilibrium studies in the analytical ultracentrifuge. Approaching half of the total amino acid sequence was determined by means of an automatic sequencer.

PMID: 11097 [PubMed - indexed for MEDLINE]

Electrogenicity of the Na+-ATPase from the marine microalga Tetraselmis (Platymonas) viridis and associated H+ countertransport.

Balnokin YV, Popova LG, Andreev IM.

Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow.

Sodium accumulation by the Na+-ATPase in the plasma membrane (PM) vesicles isolated from the marine alga Tetraselmis (Platymonas) viridis was shown to be accompanied by deltapsi generation across the vesicle membrane (positive inside) and H+ efflux from the vesicle lumen. Na+ accumulation was assayed with 22Na+; deltapsi generation was detected by recording absorption changes of oxonol VI; H+ efflux was monitored as an increase in fluorescence intensity of the pH indicator pyranine loaded into the vesicles. Both ATP-dependent Na+ uptake and H+ ejection were increased by the H+ ionophore carbonyl cyanide m-chlorophenylhydrazone (CICCP) while deltapsi was collapsed. The lipophilic anion tetraphenylboron ion (TPB-) inhibited H+ ejection from the vesicles and abolished deltapsi. Based on the effects of CICCP and TPB- on H+ ejection and deltapsi generation, the conclusion was drawn that H+ countertransport observed during Na+-ATPase operation is a secondary event energized by the electric potential which is generated in the course of Na+ translocation across the vesicle membrane. Increasing Na+ concentrations stimulated H+ efflux and caused the decrease in the deltapsi observed, thus indicating that Na+ is likely a factor controlling H+ permeability of the vesicle membrane.

PMID: 10622734 [PubMed - indexed for MEDLINE]

High-resolution XANES studies on vanadium-containing haloperoxidase: pH-dependence and substrate binding.

Kusthardt U, Hedman B, Hodgson KO, Hahn R, Vilter H.

Lehrstuhl fur Anorganische Chemie I, TU Munchen, Garching, Germany.

High-resolution X-ray absorption vanadium K-edge spectra were recorded for samples of vanadium-containing bromoperoxidase from the brown alga, Ascophyllum nodosum, at pH 9, 7, 5 and 4, as well as for enzyme samples containing the substrates, hydrogen peroxide and bromide. The well-resolved features of the XANES spectra are discussed. The pH-dependence of the structure of the active site has been studied revealing no significant change of the absorption features. We were able to detect an interaction of H2O2 with the vanadium site of the bromoperoxidase using XAS spectroscopy, whereas addition of bromide causes no energy shift of the XANES spectrum. The possible role of vanadium during the enzymatic reaction is discussed on the basis of our results.

PMID: 8354407 [PubMed - indexed for MEDLINE]

Interactions of chromium with microorganisms and plants.

Cervantes C, Campos-Garcia J, Devars S, Gutierrez-Corona F, Loza-Tavera H, Torres-Guzman JC, Moreno-Sanchez R.

Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana, Edificio B-3, Ciudad Universitaris, 58030 Morelia, Michoacan, Mexico. [email protected]

Chromium is a highly toxic non-essential metal for microorganisms and plants. Due to its widespread industrial use, chromium (Cr) has become a serious pollutant in diverse environmental settings. The hexavalent form of the metal, Cr(VI), is considered a more toxic species than the relatively innocuous and less mobile Cr(III) form. The presence of Cr in the environment has selected microbial and plant variants able to tolerate high levels of Cr compounds. The diverse Cr-resistance mechanisms displayed by microorganisms, and probably by plants, include biosorption, diminished accumulation, precipitation, reduction of Cr(VI) to Cr(III), and chromate efflux. Some of these systems have been proposed as potential biotechnological tools for the bioremediation of Cr pollution. In this review we summarize the interactions of bacteria, algae, fungi and plants with Cr and its compounds.

Publication Types:

Review

Review, Academic

PMID: 11348688 [PubMed - indexed for MEDLINE]

Biosorption of copper and zinc by Cymodocea nodosa.

Sanchez A, Ballester A, Blazquez ML, Gonzalez F, Munoz J, Hammaini A.

Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, Facultad de Ciencias Quimicas, Universidad Complutense, 28040, Madrid, Spain.

The adsorption of the two metal ions Cu and Zn in a single-component system by Cymodocea nodosa, a brown alga, under different pH conditions was investigated. The solution pH significantly affected the exhibited uptake, being maximum at a pH value of 4.5. Multi-component mixture biosorption in aqueous solutions is also reported. A comparison was made between the single-component saturation uptake and the multi-component uptakes. To evaluate the two-metal sorption system performance, simple isotherm curves had to be replaced by three-dimensional sorption isotherm surfaces. In order to describe the isotherm surfaces mathematically, three Langmuir-type models were evaluated. The isotherms indicate a competitive uptake with Cu being preferentially adsorbed. In addition, different tests were carried out to compare the process efficiency working continuously in small columns.

PMID: 10525164 [PubMed - indexed for MEDLINE]

Advances in biosorption of metals: selection of biomass types.

Volesky B.

Department of Chemical Engineering, McGill University, Montreal, Canada.

Within the past decade, the potential of metal biosorption has been well established. For economic reasons, of particular interest are abundant biomass types either generated as a waste by-product of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. Some of these high metal-sorbing biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for detoxification of metal-bearing industrial effluents. Ions of lead and cadmium, for instance, have been found to be bound very efficiently from very dilute solutions by the dried biomass of some ubiquitous brown marine algae such as Ascophyllum and Sargassum which accumulate more than 30% of biomass dry weight in the metal. Mycelia of industrially steroid-transforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium, binding also other heavy metals up to 25% of the biomass dry weight. The common yeast Saccharomyces cerevisiae is a 'mediocre' metal biosorbent. Construction of biosorption isotherm curves serves as a basic technique assisting in evaluation of the metal uptake by different biosorbents. The methodology is based on batch equilibrium sorption experiments extensively used for screening and quantitative comparison of new biosorbent materials. Experimental methodologies used in the study of biosorption and selected recent research results demonstrate the route to novel biosorbent materials some of which can even be repeatedly regenerated for re-use.

PMID: 7917417 [PubMed - indexed for MEDLINE]

Certification of trace and major elements and methylmercury concentrations in a macroalgae (Fucus sp.) reference material, IAEA-140.

Coquery M, Carvalho FP, Azemard S, Bachelez M, Horvat M.

International Atomic Energy Agency, Marine Environment Laboratory, Principality of Monaco.

A marine reference material, IAEA-140, prepared with a macroalgae (Fucus sp.) was recently produced by the International Atomic Energy Agency and certified for trace and major elements and for methylmercury (MeHg). Certification of this material was achieved as an outcome of an international analytical intercomparison study which resulted in 116 independent sets of results reported by participants from 54 countries. The statistical evaluation of the collected data and the criteria used for assignment of the mean and uncertainty values are described. The analysis of data allowed to certify concentration values for 24 elements and MeHg, and to provide information values for another 10 elements. Regarding the elements which could be given certified values, between two and eight different instrumental methods were used to measure metal concentrations, and four independent analytical procedures were used to measure MeHg concentrations. In order to assess the results of the certification procedure, a comparison was made between the certified values obtained from the world-wide intercomparison results and the values obtained from a small subgroup of well-qualified laboratories. The means and 95% confidence intervals for reference values obtained by the two methods are similar for most elements showing that the usual method of certification used by the IAEA, based on large groups of participants, is indeed pertinent.

Publication Types:

Evaluation Studies

Multicenter Study

PMID: 11227410 [PubMed - indexed for MEDLINE]

Comparison of open microwave digestion and digestion by conventional heating for the determination of Cd, Cr, Cu and Pb in algae using transverse heated electrothermal atomic absorption spectrometry.

Meeravali NN, Kumar SJ.

National Centre for Compositional Characterization of Materials, Hyderabad, India.

A comparison between open microwave digestion and digestion by conventional heating was carried out for the determination of Cd, Cr, Cu, and Pb in two algae matrices using transverse heated electrothermal atomic absorption spectrometry (ETAAS). A SRM GBW 08504 cabbage was also analysed. These matrices were digested with HNO3, using a quartz vessel for microwave digestion and PFA vessel for digestion by conventional heating. Cd, Cu and Cr were determined without any modifier, while magnesium nitrate and ammonium phosphate mixed modifier was used for Pb. Results obtained by both the procedures were in good agreement with each other at 95% confidence level, and for SRM GBW 08504 cabbage the values agree well with the certified values. The limits of detection obtained were 0.0004, 0.060, 0.065 and 0.054 mg/kg for Cd, Cr, Cu, and Pb, respectively, using the microwave digestion process. The RSD for Cd was 10-15% and for the other elements 5-10%.

PMID: 11225680 [PubMed - indexed for MEDLINE]

Vanadium in marine mussels and algae.

Sperling KR, Bahr B, Ott J.

Alfred-Wegener-Institut fur Polar- und Meeresforschung Haus C, Bremerhaven, Germany.

A method is presented which is sensitive enough for the determination of vanadium (V) in marine organisms such as mussels and algae. It was sufficiently checked by a reference material and it was applied to V determination in blue mussels and brown algae from the German Bight.

PMID: 11225913 [PubMed - indexed for MEDLINE]

[Alimentary methods for decreasing the radiation load of the body with cesium and strontium radionuclides]

[Article in Russian]

Shandala NK.

Introduction in ration of fish mass, calcium carbonate, bone meal, algae laminaria reduced level of Sr-90 and Cs-137 accumulation in the population living on territories polluted after Chernobyl accident

PMID: 8163235 [PubMed - indexed for MEDLINE]

Short-term bioconcentration studies of Np in freshwater biota.

Poston TM, Klopfer DC, Simmons MA.

Pacific Northwest Laboratory, Richland, WA 99352.

Short-term laboratory exposures were conducted to determine the potential accumulation of Np in aquatic organisms. Concentration factors were highest in green algae. Daphnia magna, a filter-feeding crustacean, accumulated Np at levels one order of magnitude greater than the amphipod Gammarus sp., an omnivorous substrate feeder. Accumulation of Np in juvenile rainbow trout (Oncorhynchus mykiss) was highest in carcass (generally greater than 78% of the total body burden) and lowest in fillets. Recommended concentration factors for Np, based on fresh weight, were 300 for green algae, 100 for filter-feeding invertebrates, for nonfilter-feeding invertebrates, 10 for whole fish, and one for fish flesh.

PMID: 2228614 [PubMed - indexed for MEDLINE]

Synopsis of French experimental and in situ research on the terrestrial and marine behavior of Tc.

Masson M, Patti F, Colle C, Roucoux P, Grauby A, Saas A.

Laboratoire de Radioecologie Marine, C.E.A., I.P.S.N., D.E.R.S., S.E.R.E., Cherbourg, France.

Terrestrial environment studies have been essentially concerned with the evolution of soil deposition and soil-plant transfers. Experimentally determined coefficients of distribution in soils are low: 60-80% of Tc remains hydrosoluble during the first months. Technetium emissions resulting from microbiological activity have been quantified. Antagonistic effects on Mo and Tc retention by soils are dependent on their respective concentrations. Four areas of soil-plant transfers have been studied: 1) root absorption kinetics relative to deposition of Tc, 2) interaction of stable Mo (environmental parameter) with the transfer of Tc to plants, 3) interaction of some long-lived radioisotopes (effluent parameters) with the transfer of Tc to plants, and 4) long-term soil-plant transfer and aging of deposited material. Of aquatic systems, only the marine environment has been studied. Under anoxic conditions in the presence of reducing sediments, the distribution coefficients (Kd) were very high (10(3)). Concentration factors (CF) from water to organisms were generally very low (1 to 10); however, CF greater than 1000 have been observed for some biota such as macrophytic brown algae, worms and lobsters. Biochemical analysis showed that Tc was essentially free and partially bonded to proteins. The transfer factors between sediments and species were very low (TF less than 0.5). The biological half-time was determined in some marine organisms that had accumulated Tc from water, food or sediments; the loss is biphasic. Uptake in edible parts was low. The physiochemical form affects the accumulation and loss of Tc. Analyses have quantified 99Tc in marine fauna and biota in the English Channel in relation with releases of the reprocessing plant of La Hague. Brown algae are the best bioindicators for following 99Tc dispersion in marine ecosystems.

Publication Types:

Review

Review, Tutorial

PMID: 2668233 [PubMed - indexed for MEDLINE]

The determination of trace transition elements in biological tissues using flameless atom reservoir atomic absorption.

Segar DA, Gilio JL.

PMID: 4752398 [PubMed - indexed for MEDLINE]

Bioavailability of iron from purple laver (Porphyra spp.) estimated in a rat hemoglobin regeneration bioassay.

Shaw NS, Liu YH.

Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan 10764, Republic of China. [email protected]

Laver belongs to the genius of Porphyra and is the most valuable seaweed in the aqua-culture industry. It contains higher iron than many other plant foods. The bioavailability of iron from laver was evaluated in a rat hemoglobin regeneration assay. Reagent-grade ferrous sulfate was used as the reference standard, and the relative biological value (RBV) for laver was expressed as a percentage of the response to ferrous sulfate. RBV was calculated by two methods: slope-ratio and ratio of hemoglobin regeneration efficiency, and both yielded RBV of 26 for laver. Amount of available iron from laver estimated from RBV was comparable to many iron-fortified foods.

PMID: 10820087 [PubMed - indexed for MEDLINE]

Extraction of mercury from groundwater using immobilized algae.

Barkley NP.

U.S. Environmental Protection Agency, Risk Reduction Engineering Laboratory, Cincinnati, Ohio.

Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algal biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into adsorption columns, exhibited excellent flow characteristics, and functioned as a "biological" ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of this product to adsorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded nonrepeatable results with samples collected at different times of the year. The strategy of sequentially extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity.

PMID: 1777231 [PubMed - indexed for MEDLINE]

The brown alga Ascophyllum nodosum contains two different vanadium bromoperoxidases.

Krenn BE, Tromp MG, Wever R.

E. C. Slater Institute for Biochemical Research and Biotechnological Centre, University of Amsterdam, The Netherlands.

Haloperoxidases have been detected in a variety of organisms, including bacteria, fungi, algae, and mammals. Mammalian haloperoxidases are known to be directly involved in the oxidative destruction of microorganisms. The algal bromoperoxidases are probably involved in the biosynthesis of bromometabolites, most of which show considerable bactericidal activity. From the brown seaweed Ascophyllum nodosum (order, Fucales) two different bromoperoxidases have been isolated, which both contain vanadium as an essential element for enzymic activity. The location of these two enzymes, determined by activity staining of cross-sections of algal parts, was different. Bromoperoxidase I (which has been described before) was located inside the thallus, particularly around the conceptacles, whereas bromoperoxidase II was present at the thallus surface of the alga. The molecular masses of these bromoperoxidases as judged from sodium dodecyl sulfate-gel electrophoresis were 97 and 106 kDa, respectively. Some of the enzymatic properties (pH optimum and Km for bromide) of the two enzymes were slightly different, whereas the amino acid compositions were more or less equal. The isoelectric point of the two proteins was the same, namely 5.0. On sodium dodecyl sulfate-polyacrylamide gels both enzymes could be stained with periodic acid Schiff's reagent, so both are glycoproteins. Since only bromoperoxidase II could be bound to a concanavalin A-Sepharose column, these enzymes contain different carbohydrates. Both enzymes display a considerable thermostability. However, the chemical stability of the two bromoperoxidases differed. Bromoperoxidase II could also be inactivated by dialysis at low pH and reactivation was only possible with the transition metal vanadium and not with other metal ions. The presence of vanadium in this enzyme could be established with atomic absorption spectrophotometry and electron paramagnetic resonance. The EPR signals of both bromoperoxidases, which were observed after reduction with sodium dithionite, were similar: only minor differences were observed in the hyperfine coupling. In immunoblotting experiments these two bromoperoxidases were found to cross-react, so they have common antigenic determinants.

PMID: 2553736 [PubMed - indexed for MEDLINE]

Composition and structure of assimilatory nitrate reductase from Ankistrodesmus braunii.

De la Rosa MA, Vega JM, Zumft WG.

Assimilatory NAD(P)H-nitrate reductase (EC 1.6.6.2) from Ankistrodesmus braunii has been purified to homogeneity by affinity chromatography on blue Sepharose. The specific activity of the purified enzyme is in the range of 72 to 80 units/mg of protein. The electronic spectrum of the native enzyme shows absorption maxima at 278, 414 (Soret), 532 (beta), 562 (alpha), and 669 nm and shoulders at 455 and 484 nm, with an A278/A414 ratio of 2.56. The reduced enzyme shows absorption maxima at 424 (Soret), 528 (beta), 557 (alpha),and 669 n. The enzyme complex (Mr = 467,400) is composed of eight similar subunits (Mr = 58,750) and contains 4 molecules of FAD, 4 heme groups, and 2 atoms of molybdenum. Labile sulfide and nonheme iron were not detected. Electron micrographs show the eight subunits arranged alternately in two planes, and an 8-fold rotational symmetry was deduced from highly magnified images processed by optical superposition.

PMID: 7195400 [PubMed - indexed for MEDLINE]

Increase of intestinal calcium absorption and bone mineral density by heated algal ingredient (HAI) in rats.

Fujita T, Fujii Y, Goto B, Miyauchi A, Takagi Y, Kobayashi S, Kamoshita K, Mikuni N, Kurihara Y, Shikauchi I.

Calcium Research Institute, Kishiwada, Osaka, Japan.

Active absorbable calcium (AAACa) produced by adding HAI (heated algal ingredient) to oyster shell calcium (AACa) is quite efficiently absorbed from the intestine and can increase bone mineral density in elderly osteoporotic patients. HAI was produced by heating the seaweed Cystophyllum fusiforme under reduced pressure, extracting with 6N HCL, and partially neutralizing it. Butanol-ethanol extraction then yielded active HAI fraction A, corresponding to about 1% in weight. The active HAI fraction increased intestinal Ca absorption as shown by a dose-dependent increase of plasma Ca in young male parathyroidectomized rats maintained on a low-Ca diet by administration through a stomach tube with a constant dose of AACa. The action of the active fraction A to maintain bone mass was then tested in young male rats kept on a low-Ca diet for 2 weeks. Bone weight, trabecular bone density, and strength-strain index as indices of bone strength measured by peripheral computed tomography (pQCT) tended to increase when the active HAI fraction was given along with Ca. HAI increased intestinal Ca absorption and prevented the decrease of bone density in rats kept on a low-Ca diet.

PMID: 10783851 [PubMed - indexed for MEDLINE]

Role of zinc in cell division of Euglena gracilis.

Falchuk KH, Fawcett DW, Vallee BL.

Euglena gracilis is a suitable model system to investigate the role of zinc in the process of cell division. In zinc-deficient organisms there is a characteristic arrest of cellular proliferation, the DNA content of the cells doubles, whereas RNA and protein contents decrease. The present investigations include the growth characteristics, changes in cellular morphology at various stages in the growth cycle, quantitation of zinc uptake and incorporation of tritium-labelled precursors into RNA by organisms grown in zinc sufficient (Zn+), (Zn2+ content 1 times 10-minus 5 M) or zinc-deficient (Zn minus), (Zn2+ content 1 times 10-7 M) medium. Cell division ceases on depletion of zinc from the medium. There are 20-fold less cells in (Zn minus) medium than in control cultures. The size of (Zn+) cells decreases during log phase due to a reduction in the paramylon content of the cytoplasm. The size of (Zn minus) cells, however, increases, due to an accumulation of paramylon. This results in a 13-fold increment in dry weight compared to control. Other cytoplasmic organelles, including Golgi bodies, mitochondria, etc. are normal. Nuclear morphology also is unchanged. There is a reduction in the rate of incorporation of labelled precursors into RNA by (Zn minus) cells. The DNA content of (Zn minus) E. gracilis, the absence of morphologic evidence to indicate that cell division has followed the doubling of the DNA, and the arrest in proliferation suggests that a critical zinc-dependent step in the cell cycle, localized to G2, is blocked in zinc deficiency.

PMID: 803510 [PubMed - indexed for MEDLINE]

Assessing metal sorption on the marine alga Pilayella littoralis.

Carrilho EN, Gilbert TR.

Department of Chemistry and The Barnett Institute, Northeastern University, Boston, MA 02115, USA.

Increasing interest in the development of biological materials for metal sorption led us to investigate the brown marine alga, Pilayella littoralis, as a biological sorbent. This work focuses on the harvest, preparation and evaluation of P. littoralis from Nahant beaches for use as a metal biosorbent. This biomass was used in batch tests with synthetic solutions. Its metal uptake properties, including metal binding capacity, the pH dependence of metal uptake and the kinetics of metal sorption, were investigated. Most metal sorption occurred within the first 5 min of exposure and the metals were optimally bound to the algae at pH 5.5. The algal binding capacities for Al(III), Cd(II), Co(II), Cr(VI), Cu(II), Fe(III), Ni(II) and Zn(II), were 2,000, 430, 560, 90, 850, 700, 390 and 450 micromol g(-1) of dried biomass, respectively. Metals were desorbed with 0.12 mol l(-1) HCl and determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

PMID: 11254041 [PubMed - indexed for MEDLINE]

Technetium-99 in the Irish marine environment.

Smith V, Fegan M, Pollard D, Long S, Hayden E, Ryan TP.

Radiological Protection Institute of Ireland, 3 Clonskeagh Square, Clonskeagh Road, Dublin 14, Ireland.

Technetium-99 activity concentrations in seawater and biota from Irish coastal waters are presented. Time series measurements of 99Tc in seawater and Fucus vesiculosus from the western Irish Sea show that activity concentrations have increased in line with the increase in discharges of 99Tc from Sellafield. The peak in activity concentrations in both seawater and Fucus vesiculosus occurred in 1997 approximately two years after the peak in 99Tc discharges. The highest activity concentration recorded in Fucus vesiculosus showed a 29-fold increase over the mean concentration for the period 1988-1993. Technetium-99 activity concentrations were measured in fish, lobsters, prawns, mussels and oysters landed at major fishing ports on the east and northeast coasts of Ireland between 1996 and 1998. Concentration factors for 99Tc in the brown seaweed Fucus vesiculosus and certain species of fish, crustaceans and molluscs from the Irish Sea were estimated. In general, these concentration factors were higher than those in the literature which were derived from laboratory studies, but agreed well with values which were based on field studies. The mean committed effective doses to Irish typical and heavy seafood consumers due to 99Tc in the period 1996-1998 were 0.061 and 0.24 microSv, respectively.

PMID: 11468819 [PubMed - indexed for MEDLINE]

Electrically triggered all-or-none Ca(2)+-liberation during action potential in the giant alga Chara.

Wacke M, Thiel G.

Albrecht-von-Haller Institute for Plant Sciences, Plant Biophysics, University of Gottingen, 37073 Gottingen, Germany.

Electrically triggered action potentials in the giant alga Chara corallina are associated with a transient rise in the concentration of free Ca(2)+ in the cytoplasm (Ca(2)+(cyt)). The present measurements of Ca(2)+(cyt) during membrane excitation show that stimulating pulses of low magnitude (subthreshold pulse) had no perceivable effect on Ca(2)+(cyt). When the strength of a pulse exceeded a narrow threshold (suprathreshold pulse) it evoked the full extent of the Ca(2)+(cyt) elevation. This suggests an all-or-none mechanism for Ca(2)+ mobilization. A transient calcium rise could also be induced by one subthreshold pulse if it was after another subthreshold pulse of the same kind after a suitable interval, i.e., not closer than a few 100 ms and not longer than a few seconds. This dependency of Ca(2)+ mobilization on single and double pulses can be simulated by a model in which a second messenger is produced in a voltage-dependent manner. This second messenger liberates Ca(2)+ from internal stores in an all-or-none manner once a critical concentration (threshold) of the second messenger is exceeded in the cytoplasm. The positive effect of a single suprathreshold pulse and two optimally spaced subthreshold pulses on Ca(2)+ mobilization can be explained on the basis of relative velocity for second messenger production and decomposition as well as the availability of the precursor for the second messenger production. Assuming that inositol-1,4,5,-trisphosphate (IP(3)) is the second messenger in question, the present data provide the major rate constants for IP(3) metabolism.

PMID: 11429441 [PubMed - indexed for MEDLINE]

Caesium accumulation by microorganisms: uptake mechanisms, cation competition, compartmentalization and toxicity.

Avery SV.

School of Pure and Applied Biology, University of Wales College of Cardiff, UK.

The continued release of caesium radioisotopes into the environment has led to a resurgence of interest in microbe-Cs interactions. Caesium exists almost exclusively as the monovalent cation Cs+ in the natural environment. Although Cs+ is a weak Lewis acid that exhibits a low tendency to form complexes with ligands, its chemical similarity to the biologically essential alkali cation K+ facilitates high levels of metabolism-dependent intracellular accumulation. Microbial Cs+ (K+) uptake is generally mediated by monovalent cation transport systems located on the plasma membrane. These differ widely in specificity for alkali cations and consequently microorganisms display large differences in their ability to accumulate Cs+; Cs+ appears to have an equal or greater affinity than K+ for transport in certain microorganisms. Microbial Cs+ accumulation is markedly influenced by the presence of external cations, e.g. K+, Na+, NH4+ and H+, and is generally accompanied by an approximate stoichiometric exchange for intracellular K+. However, stimulation of growth of K(+)-starved microbial cultures by Cs+ is limited and it has been proposed that it is not the presence of Cs+ in cells that is growth inhibitory but rather the resulting loss of K+. Increased microbial tolerance to Cs+ may result from sequestration of Cs+ in vacuoles or changes in the activity and/or specificity of transport systems mediating Cs+ uptake. The precise intracellular target(s) for Cs(+)-induced toxicity has yet to be clearly defined, although certain internal structures, e.g. ribosomes, become unstable in the presence of Cs+ and Cs+ is known to substitute poorly for K+ in the activation of many K(+)-requiring enzymes.

Publication Types:

Review

Review, Tutorial

PMID: 7766213 [PubMed - indexed for MEDLINE]

The uptake and metabolism of urea by Chara australis: IV. Symport with sodium--a slip model for the high and low affinity systems.

Walker NA, Reid RJ, Smith FA.

Biophysics Laboratory, School of Biological Sciences, University of Sydney, NSW, Australia.

We have previously investigated the electrogenic influx of urea in Chara, and the urea- and sodium-dependent membrane current. We have shown that there is a sodium-stimulated component of urea influx and a urea-stimulated component of sodium influx, and that these are of the same size. We conclude that the electrogenic inward transport of urea, and of its analogues acetamide and acrylamide, is by sodium symport, with a stoichiometric ratio of 1:1. The kinetics of the fluxes and currents show two different KM values for sodium in different cells and two different kinds of kinetics for the effect of urea on membrane current, one of which fits the Michaelis-Menten equation, while the other shows a maximum and fits the difference of two Michaelis-Menten terms, suggesting a phenomenon like cis-inhibition. Similarities in kinetic characteristics between the inhibitory site and the electrically silent uptake site (System II) lead us to suggest that the same protein may be responsible for both the low-KM, electrogenic influx of urea (System I) and the high-KM, electrically silent influx by System II. We suggest a "slip" model for urea uptake in Chara.

PMID: 8114076 [PubMed - indexed for MEDLINE]

Patch-clamp studies on the anomalous mole fraction effect of the K+ channel in cytoplasmic droplets of Nitella: an attempt to distinguish between a multi-ion single-file pore and an enzyme kinetic model with lazy state.

Draber S, Schultze R, Hansen UP.

Institut fur Angewandte Physik, Kiel, Federal Republic of Germany.

Patch-clamp studies have been employed in order to check whether the assumption of a multi-ion single-file pore is necessary for the explanation of the anomalous mole fraction effect or whether this effect can also be explained by a single-barrier enzyme kinetic model. Experiments in the cell-attached configuration were done on the tonoplast membrane of cytoplasmic droplets of Nitella in solutions containing 150 mol m-3 of K+ plus Tl+ with seven different K+/Tl+ ratios. At first sight, the results seem to support the multi-ion single-file pore, because apparent open channel conductivity displays the anomalous mole fraction effect, whereas open-probability has not been found to be dependent on the K+/Tl+ ratio. Changes in open probability would be expected for a single-barrier enzyme kinetic model with a lazy state. On the other hand, the lazy-state model is more successful in explaining the measured I-V curves. The entire slope of the apparent open channel current-voltage curves rotates with changing K+/Tl+ ratios in the whole voltage range between -100 and +80 mV. Numerical calculations on the basis of multi-ion single-file pores could create the anomalous mole fraction effect only in a limited voltage range with intersecting I-V curves. The apparent absence of an effect on open probability which is postulated by the lazy-state model can be explained if switching into and out of the lazy state is faster than can be resolved by the temporal resolution of 1 msec.

PMID: 1956073 [PubMed - indexed for MEDLINE]

Isolation of the nickel-chlorin chelate tunichlorin from the South Pacific ocean sea hare Dolabella auricularia.

Pettit GR, Kantoci D, Doubek DL, Tucker BE, Pettit WE, Schroll RM.

Cancer Research Institute, Arizona State University, Tempe 85287-1604.

The Papua New Guinea shell-less mollusc Dolabella auricularia has been found to contain a series of green to blue-green chlorins. One of these compounds was found to be the nickel chelate tunichlorin [1] which was isolated previously only from the Caribbean tunicate Trididemnum solidum. Discovery of tunichlorin [1] in a sea hare suggests that its occurrence in algae-consuming marine animals may be more common than earlier realized, and it may have a role in electron transfer or other metabolic processes.

PMID: 8289065 [PubMed - indexed for MEDLINE]

Bioavailability of magnesium contained in purple laver (Asakusa-Nori) by rats with scarce magnesium, being evaluated from serum magnesium, kidney calcification, and bone magnesium contents.

Esashi T, Hanai M.

Division of Geriatric Health Science, National Institute of Health and Nutrition, Tokyo, Japan.

An experiment was designed to evaluate the bioavailability of purple laver (Asakusa-Nori, Porphyra tenera Kjellman) magnesium (Mg) in Mg-scarcity Fischer 344 male rats from serum Mg level, kidney calcification and bone Mg contents. Male rats of 4 weeks of age were divided into four groups of six rats. The four groups were control (20SC), Mg-restricted (-Mg20SC), -Mg20SC plus purple laver (-Mg20SCP), and 20SC plus purple laver (20SCP) group respectively. To -Mg20SC, 1/10 Mg of the 20SC diet was added. -Mg20SCP diet purple laver as a Mg source. 20SCP diet was designed to contain double amount of Mg. After a 3-week experimental period, rats were decapitated. Blood serum, right kidney, and right femur were collected and Mg, calcium (Ca), phosphorus (P) were determined. Serum Mg concentration of the -Mg20SC was 1/3 of the 20SC, indicating apparent hypomagnesemia. Serum P also showed lowered concentration. On the other hand, the serum Ca indicated higher value than the other groups, indicating hypercalcemia. Addition of purple laver to -Mg20SC diet resulted in a normal serum Mg, Ca, and P level. The Mg-scarcity (-Mg20SC) rats accumulated much amount of kidney Ca. Whereas, there was no significant difference in kidney Ca between control (20SC) group and purple laver-supplemented (-Mg20SCP) rat group. The -Mg20SC rats showed lowered ash content and reduced Mg and P concentrations in the femur. Purple laver supplementation increased the ash, Mg, and P. All of the results indicated that the purple laver Mg was used as a Mg source.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 8283317 [PubMed - indexed for MEDLINE]

Vertical distribution of potentially pathogenic free-living amoebae in freshwater lakes.

Kyle DE, Noblet GP.

The vertical distribution of thermotolerant (37 degrees C and 45 degrees C) free-living amoebae (FLA) in warm monomictic lakes was determined in relation to the onset of thermal stratification and associated physical and chemical changes. The position of abiotic or biotic particulate layers in the water column was located by using a submersible horizontal beam transmissometer that measures attenuance, or the absorption and scattering of light by particulates in the water column. During mixis, the vertical distribution of amoebae was sporadic with significant numbers of FLA only occurring in clay layers caused by runoff after heavy rains. With the onset of thermal stratification in the lakes, phytoplankton layers began to form. Few amoebae were isolated from layers containing flagellated phytoplankton; however, significant (P less than 0.005) numbers of FLA were isolated from two particulate layers dominated by the filamentous blue-green algae Aphanizomenon and Lyngbya, respectively. By late June, a persistent detrital or decomposition layer formed in the lower metalimnion, as well as a hypolimnetic iron layer where the Fe2+ state was predominant. In this midsummer period, 13 Naegleria fowleri were isolated, with three from the detrital layer and seven from the iron layer. The presence of attenuation zones was found to be the best indicator of the vertical distribution of FLA in the water column, and such layers represent an important, previously undescribed habitat for potentially pathogenic FLA.

PMID: 3989753 [PubMed - indexed for MEDLINE]

[Age and the absorption of mineral substances from nutrient medium by chlorella cells]

[Article in Russian]

Lebedeva EK, Antonian AA, Galkina TB, Meleshko GI.

PMID: 4652078 [PubMed - indexed for MEDLINE]

Copper-responsive gene expression during adaptation to copper deficiency.

Quinn JM, Merchant S.

Department of Chemistry and Biochemistry, University of California, Los Angeles 90095, USA.

PMID: 9750208 [PubMed - indexed for MEDLINE]

Nutritive value of marine algae Laminaria japonica and Undaria pinnatifida.

Jurkovic N, Kolb N, Colic I.

Department of Nutrition and Food Chemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Croatia.

The chemical composition, that is crude proteins, fats, carbohydrates, cellulose, ashes, minerals and nucleic acids were determined in two commercially available marine algae: Laminaria japonica and Undaria pinnatifida. The energetic value and energetic share of proteins, fats and carbohydrates were calculated. The results were discussed in terms of importance of marine algae in human diet.

PMID: 7898578 [PubMed - indexed for MEDLINE]

[Physiopathology of iron absorption from food in patients after partial gastrectomy, observation using F59-labeled chlorella]

[Article in Japanese]

Kameda A.

PMID: 5358681 [PubMed - indexed for MEDLINE]

Uptake of dissolved organic carbon and trace elements by zebra mussels.

Roditi HA, Fisher NS, Sanudo-Wilhelmy SA.

Marine Sciences Research Center, State University of New York, Stony Brook 11794-5000, USA.

Zebra mussels (Dreissena polymorpha) are widespread and abundant in major freshwater ecosystems in North America, even though the phytoplankton food resources in some of these systems seem to be too low to sustain them. Because phytoplankton biomass is greatly depleted in ecosystems with large D. polymorpha populations and bacteria do not seem to be an important food source for this species, exploitation of alternative carbon sources may explain the unexpected success of D. polymorpha in such environments. Here we examine the possibility that absorption of dissolved organic carbon (DOC) from water could provide a nutritional supplement to zebra mussels. We find that mussels absorb 14C-labelled DOC produced by cultured diatoms with an efficiency of 0.23%; this indicates that DOC in natural waters could contribute up to 50% of the carbon demand of zebra mussels. We also find that zebra mussels absorb some dissolved metals that have been complexed by the DOM; although absorption of dissolved selenium was unaffected by DOC, absorption of dissolved cadmium, silver and mercury by the mussels increased 32-, 8.7- and 3.6-fold, respectively, in the presence of high-molecular-weight DOC.

PMID: 10993076 [PubMed - indexed for MEDLINE]

Mercury in marine organisms of the Tay region.

Jones AM, Jones Y, Stewart WD.

PMID: 4558461 [PubMed - indexed for MEDLINE]

[Ingestion and excretion of aluminum in foods and pharmaceuticals]

[Article in Japanese]

Matsushima F, Meshitsuka S.

Tottori College, 884 Fukuba, Kurayoshi, Tottori 682-8555, Japan.

We measured the aluminum contents in foods and pharmaceuticals, and the aluminum concentrations in urine by atomic absorption spectrophotometry with polarized Zeeman background correction to obtain the daily intake and excretion of aluminum. The daily urinary excretions of aluminum in healthy females were obtained after consuming sea algae, hizikia fusiforme, which has a high aluminum contents. Daily aluminum excretion did not increase after taking hizikia fusiforme. On the other hand, high aluminum excretions were observed after taking an analgesic/antipyretic with a high aluminum contents, compared with the usual daily aluminum excretion (p < 0.001), and compared with after taking an analgesic/antipyretic with no aluminum (p < 0.0001). We found that the daily urinary excretion of aluminum was not related to the total consumption of aluminum, but depended on the binding state of aluminum consumed.

PMID: 11519187 [PubMed - indexed for MEDLINE]

[Absorption and excretion of Chlorella ellipsoidea cadmium binding protein in rats]

[Article in Japanese]

Nagano T, Suketa Y, Okada S.

PMID: 6668715 [PubMed - indexed for MEDLINE]

Fate of copper in ponds.

McIntosh AW.

Treatments of 3 ppm copper sulfate (CuSO4-5H2O) were applied to two small aquatic systems in Michigan in 1971. To study the pathways of the added copper, samples of water, sediment, aquatic macrophytes, filamentous algae, and fish were collected and analyzed by atomic absorption. Sampling was initiated before treatment and continued up to 4 months in one of the ponds. Dissolved copper concentrations in water decreased rapidly immediately after treatment and then gradually to background levels. Reduction of dissolved copper may have involved initial precipitation of an insoluble compound, such as malachite, followed by sediment adsorption of soluble copper complexes and copper released from aquatic plants. Levels of copper in sediment increased rapidly at first and gradually later in the study. Aquatic plants and filamentous algae accumulated very high levels of copper. Uptake rates were apparently affected by water temperature and growth stages of the plants. Data indicate that aquatic macrophytes developing in one pond 10 weeks after treatment took up copper from the sediment. Although green sunfish (Lepomis cyanellus) accumulated copper soon after treatment, levels returned to background later in the study.

PMID: 1161446 [PubMed - indexed for MEDLINE]

The bioavailability of magnesium from Wakame (Undaria pinnatifida) and Hijiki (Hijikia fusiforme) and the effect of alginic acid on magnesium utilization of rats.

Kikunaga S, Miyata Y, Ishibashi G, Koyama F, Tano K.

Faculty of Sciences of Human Life, Notre Dame Seishin University, Okayama, Japan.

The bioavailability of magnesium from Wakame and Hijiki, and the effects of alginic acid on absorption of dietary magnesium were examined in five groups of rats fed either control, Wakame, Hijiki, AW (containing the same amount of alginate as in the Wakame) and AH (containing the same amount of alginate as in the Hijiki) diets, and animals fed a low magnesium diet (LMg) (twentieth amount of magnesium in the original mineral mixtures as the control). Food intake and body weight gain were decreased by adding sodium alginate to the diets. A large amount of calcium accumulated only in the kidneys of the rats fed the LMg diet. Serum magnesium concentration decreased only in the LMg group. The magnesium content in the defatted left femurs did not differ between the control and Wakame fed animals and also among the animals eating Wakame, Hijiki and AW diets. The breaking force of the right femurs did not differ among all the groups except the LMg group. The ratio of apparent magnesium absorption (%) of the control, LMg, Wakame, Hijiki, AW and AH groups was 82.2, 72.7, 66.9, 50.8, 69.3 and 54.2 in the first experimental period, and was 75.3, 52.1, 57.7, 46.9, 62.6 and 60.5 in the second experimental period, respectively. It was clear that the bioavailability of magnesium in the Wakame fed rats was higher than in those eating the Hijiki. Large amounts of sodium alginate lowered magnesium absorption from the diet.

PMID: 10517285 [PubMed - indexed for MEDLINE]

Chlamydomonas contains calcium stores that are mobilized when phospholipase C is activated.

Kuin H, Koerten H, Ghijsen WE, Munnik T, van den Ende H, Musgrave A.

Institute for Molecular Cell Biology, BioCentrum Amsterdam, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.

Mastoparan induces Ca(2+)-dependent deflagellation of the unicellular green alga Chlamydomonas moewusii Gerloff, as well as the activation of phospholipase C and the production of inositol 1,4, 5-trisphosphate (InsP(3); T. Munnik et al., 1998, Planta 207: 133-145). Even in the absence of extracellular Ca(2+), mastoparan still induces deflagellation (L.M. Quarmby and H.C. Hartzell, 1994, J Cell Biol 124: 807-815; J.A.J. van Himbergen et al., 1999, J Exp Bot, in press) suggesting that InsP(3) mediates Ca(2+) release from intracellular stores. To test this hypothesis, cells were pre-loaded with (45)Ca(2+) and their plasma membranes permeabilized by digitonin. Subsequent treatment of the cells with mastoparan (3.5 &mgr;M) induced release of intracellular (45)Ca(2+). Mastoparan also activated phospholipase C in permeabilized cells, as demonstrated by the breakdown of (32)P-phosphatidylinositol 4,5-bisphosphate and the production of diacylglycerol. The mastoparan analogues mas7 and mas17 were also effective and their efficacy was correlated with their biological activity. X-ray microanalysis showed that electron-dense bodies (EDBs) are a major Ca(2+) store in C. moewusii. Analysis of digitonin-permeabilized cells showed that EDBs lost calcium at digitonin concentrations that released radioactivity from (45)Ca(2+)-labelled cells, suggesting that (45)Ca(2+) monitored the content of EDBs. X-ray microanaysis of living cells treated with mastoparan also revealed that calcium was released from EDBs.

PMID: 10664135 [PubMed - indexed for MEDLINE]

A cobalt-porphyrin enzyme converts a fatty aldehyde to a hydrocarbon and CO.

Dennis M, Kolattukudy PE.

Ohio State Biotechnology Center, Ohio State University, Columbus 43210.

The final step in hydrocarbon biosynthesis involves loss of CO from a fatty aldehyde. This decarbonylation is catalyzed by microsomes from Botyrococcus braunii. Among the several detergents tested for solubilizing the decarbonylase, octyl beta-glucoside (0.1%) was found to be the most effective and released 65% of the enzyme activity in soluble form. FPLC of the solubilized enzyme preparation with Superose 6 followed by ion-exchange FPLC with Mono Q resulted in 200-fold increase in specific activity with 7% recovery. The purified enzyme released nearly 1 mol of CO for each mol of hydrocarbon. SDS/PAGE of the enzyme preparation showed two protein bands of equal intensity at 66 and 55 kDa. The absorption spectrum of the enzyme with bands at 410 nm, 425 nm, 580 nm, and 620 nm suggests the presence of a porphyrin. Electron microprobe analysis revealed that the enzyme contained Co. Purification of the decarbonylase from B. braunii grown in 57CoCl2 showed that 57Co coeluted with the decarbonylase. These results suggest that the enzyme contains Co that might be part of a Co-porphyrin, although a corrin structure cannot be ruled out. Co-protoporphyrin IX itself caused decarbonylation of octadecanal at 60 degrees C, whereas the metal ion or protoporphyrin alone, or several other metal porphyrins, did not cause decarbonylation. These results strongly suggest that biosynthesis of hydrocarbons is effected by a microsomal Co-porphyrin-containing enzyme that catalyzes decarbonylation of aldehydes and, thus, reveal a biological function for Co in plants.

PMID: 1608940 [PubMed - indexed for MEDLINE]

Greatly decreased susceptibility of nonmetabolizing cells towards detergents.

Komor E, Weber H, Tanner W.

The addition of different detergents to Chlorella cells that had previously accumulated 6-deoxyglucose causes a rapid release of the hexose analogue into the medium. This effect is independent of the nature of the detergent and is observed only when the cells are in an energized state. Thus, in the presence of the uncoupler p-trifluoromethoxycarbonylcyanide phenylhydrazone or of inhibitors such as N-ethylmaleimide, the cells show a greatly reduced susceptibility towards detergents. Similarly, the detergent-induced loss of accumulated alpha-aminoisobutyric acid from Saccharomyces cerevisiae and of potassium from Escherichia coli is also strongly affected by the energy state of the cells. The differential susceptibility of energized and nonenergized cells was observed at all detergent concentrations tested. Measurements of substrate efflux at different concentrations of Triton indicated that only Triton monomers are responsible for the increase in permeability. The absorption of [14C]Triton X-100 by Chlorella and the binding of detergent to the cells were measured in the presence of metabolic inhibitors. Again, nonenergized cells bound a significantly lower amount of Triton X-100. The amphiphilic antibiotic nystatin produced effects on cell permeability similar to those of detergents, whereas toluene, which is apolar, gave opposite results.

PMID: 377284 [PubMed - indexed for MEDLINE]

Metal accumulation in the green macroalga Ulva fasciata: effects of nitrate, ammonium and phosphate.

Lee WY, Wang WX.

Department of Biology, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon.

Coastal organisms are often exposed to both metal pollution and nutrient enrichment. The influences of major nutrients (nitrate, ammonium, and phosphate) on the accumulation of trace metals (Cd, Cr, Zn and Se) in Ulva fasciata were examined. The relative accumulation of metals was quantified by the kinetic measurements of accumulated metal concentration over a short exposure period (8 h). Our study demonstrated that macronutrients could markedly influence the rate of metal accumulation in the macroalgae. An increase in ambient nitrate concentration resulted in a significant increase in Cd accumulation rate, whereas the rate of accumulation of Cr and Zn was not greatly affected by the ambient nitrate level (between 10 and 100 microM). Zn uptake in nitrate-enriched macroalgae was, however, significantly higher than its uptake in N-starved macroalgae. The accumulation of Cd, Cr and Zn was not appreciably affected by the concentration of ammonium. Se accumulation was significantly inversely related to the ambient phosphate concentration, presumably due to the competitive inhibition by a high P concentration. Cr accumulation in the macroalgae increased significantly with increasing phosphate concentration. These data implied that the influences of major nutrients on cationic and anionic metal accumulation were highly metal-specific. The dependence of metal accumulation on major nutrients will appreciably affect our prediction of metal accumulation in macroalgae and the interpretation of biomonitoring data using the Ulva species.

PMID: 11669259 [PubMed - indexed for MEDLINE]

Aluminium and iron burdens of aquatic biota in New Zealand streams contaminated by acid mine drainage: effects of trophic level.

Winterbourn MJ, McDiffett WF, Eppley SJ.

Department of Zoology, University of Canterbury, Christchurch, New Zealand. [email protected]

Concentrations of Al and Fe were determined in samples of filamentous algae, bryophytes and invertebrates from 24 stream sites in North Westland, South Island, New Zealand. Sites were variably contaminated by acid coal mine drainage and ranged in pH from 2.6 to 6.2. Conductivity of stream water ranged from 16 to 944 microS25 cm(-1) and maximum concentrations of total dissolved Al and total Fe measured in two successive years were 35.5 and 32.6 mg l(-1), respectively. Metal burdens of algae and bryophytes were not correlated with pH, conductivity or the concentrations of Al and Fe observed in stream water. Metal concentrations in invertebrates were significantly lower than those in plants (mg per g dry wt.), and were similar in herbivore-detritivores (mainly mayfly larvae) and carnivorous species. No evidence was found for the biomagnification of either metal within aquatic food webs. However, invertebrate species exposed to very high concentrations of Al and Fe varied considerably in body burdens, suggesting that groups of insects differ considerably in their physiological or morphological ability to exclude potentially toxic metals.

PMID: 10845446 [PubMed - indexed for MEDLINE]

Temporal changes of 210Po in temperate coastal waters.

Wildgust MA, McDonald P, White KN.

School of Biological Sciences, University of Manchester, UK. [email protected]

The temporal variation of Polonium-210 (210Po) was examined in coastal sea water, the mussel Mytilus edulis, the winkle Littorina littorea and green alga Ulva lactuca in order to investigate the entry of 210Po into the marine food chain. More than 99% of 210Po in the water column occurred in the particulate phase. Dissolved 210Po concentrations peaked during the spring phytoplankton bloom and it is suggested this is related to preferential scavenging of 210Po by the increased numbers of bacteria, viruses and small dissolved particulates. Changes in L. littorea 210Po specific activity are thought not to be related to food, but to a drop in body weight following spawning. Much of the 210Po accumulated by M. edulis was located in the digestive gland. The specific activity of 210Po in the digestive gland of M. edulis was shown to be strongly correlated with changes in sea water suspended particulate specific activity. Examination of other trace metal (Ag, Al, As, Ca, Cd, Cr, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Sb, Se, Sn and Zn) variations in the digestive gland revealed that class B and borderline metals had a strong positive correlation with 210Po. On-going work is investigating whether the accumulation and loss of 210Po is affected by the presence of metallothioneins.

PMID: 9646514 [PubMed - indexed for MEDLINE]

Statistical evaluation of ecosystem properties influencing the uptake of As, Cd, Co, Cu, Hg, Mn, Ni, Pb and Zn in seaweed (Eucus vesiculosus) and common mussel (Mytilus edulis).

Struck BD, Pelzer R, Ostapczuk P, Emons H, Mohl C.

Institut fur Angewandte Physikalische Chemie, Forschungszentrum Julich GmbH, Germany.

In order to evaluate the influence of geographically varying marine ecosystem properties on the uptake of trace elements in bioindicators, samples were taken of seaweed (Fucus vesiculosus) and common mussel (Mytilus edulis) along the North Sea and Baltic Sea coast. Seasonal variations of the bioindicator status were minimized by sampling within 1 month. Ecosystem properties considered were the geographical position, the salinity and the concentrations of the macroelements Ca, Fe, K, Mg, Na, P and S in the bioindicators. Trace elements studied were As, Cd, Co, Cu, Hg, Mn, Ni, Pb and Zn. Factor analysis of the concentration patterns in the bioindicators and of salinity as a function of location confirmed the influence of the geographically varying salinity on the biological uptake of macroelements and trace elements. This influence of salinity was higher in the case of seaweed than in the case of mussel. Comparison of the geographical courses of the macroelement and trace-element concentrations by cluster analysis revealed corresponding courses for As and Hg in both bioindicators. All other elements showed different courses in seaweed and mussel. Subsequent cluster analysis comparing locations with respect to the macroelement or trace-element concentration patterns in the bioindicators, indicated a clear separation of North and Baltic Sea locations. However, the trace-element concentration patterns provided a regionally less distinctive ecosystem arrangement than those of the macroelement ones. The results of the cluster analysis were verified by discriminant analysis forming groups of locations with respect to geographical position and salinity. Results of discriminant analysis demonstrated, both for seaweed and for mussel as bioindicators, that the location groups formed according to the macroelement concentration patterns corresponded well with the geographical regions in the order of salinity. On the other hand, location groups based on the trace-element concentration patterns again showed a modified less distinctive ecosystem arrangement than the location groups based on macroelement concentration patterns. This confirms modified conditions for the uptake of trace elements in seaweed or mussel in comparison to the uptake of macroelements.

PMID: 9397597 [PubMed - indexed for MEDLINE]

Evaluation of the effect of temperature, pH, and bioproduction on Hg concentration in sediments, water, molluscs and algae of the delta of the Ebro river.

Schuhmacher M, Domingo JL, Llobet JM, Corbella J.

Laboratory of Toxicology and Biochemistry, School of Medicine, University of Barcelona, Reus, Spain.

The effects of temperature, pH, and bioproduction on mercury levels in sediments, water, molluscs and algae from the delta of the Ebro river (NE Spain) were determined in this study. Mercury concentrations were measured in a cold-vapor atomic absorption spectrophotometer. The ranges of mercury concentrations were the following: sediments, 0.014-0.185 microgram g-1; water, 0.001-0.018 microgram g-1; molluscs, 0.118-0.861 microgram g-1; and algae 0.008-0.026 microgram g-1. Although not statistically significant, a decrease in the pH of the water corresponded with a diminution in the content of mercury in sediments and molluscs, while the mercury levels in water and algae were lower in the areas with high levels of bioproduction. The concentrations of mercury in water significantly decreased with temperature. However, the differences with temperature of the mercury concentrations in sediments did not reach the level of significance. Consequently, water would not be an adequate indicator to determine the levels of mercury contamination, although both sediments and molluscs can be used for this purpose.

PMID: 8108702 [PubMed - indexed for MEDLINE]

Arctic marine ecosystem contamination.

Muir DC, Wagemann R, Hargrave BT, Thomas DJ, Peakall DB, Norstrom RJ.

Department of Fisheries and Oceans, Central and Arctic Region, Winnipeg, Canada.

The current state of knowledge of levels, spatial and temporal trends of contaminants in the Arctic marine ecosystem varies greatly among pollutants and among environmental compartments. Levels of polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and some heavy metals such as mercury and lead, in Arctic marine mammals and fish are relatively well documented because of the need for comparisons with biota in more polluted environments and interest in the contamination of native diets. Levels of heavy metals, alkanes, polyaromatic hydrocarbons (PAH) and OCs in the Arctic Ocean are comparable to uncontaminated ocean waters in the mid-latitudes. But concentrations of alpha- and gamma-hexachlorocyclohexane (HCHs) are higher in northern waters far removed from local sources, possibly because lower water temperature reduces transfer to the atmosphere. Bioaccumulation of OCs and heavy metals in Arctic marine food chains begins with epontic ice algae or phytoplankton in surface waters. Polychlorinated camphenes (PCC), PCBs, DDT- and chlordane-related compounds are the major OCs in marine fish, mammals and seabirds. Mean concentrations of most PCBs and OC pesticides in ringed seal (Phoca hispida) and polar bear (Ursus maritimus) populations in the Canadian Arctic are quite similar indicating a uniform geographic distribution of contamination, although alpha-HCH showed a distinct latitudinal gradient in bears due to higher levels in zones influenced by continental runoff. Ringed seals from Spitzbergen have higher levels of PCBs, total DDT and polychlorinated dioxins/furans (PCDD/PCDFs). In contrast to other OCs, PCDD/PCDFs in Canadian Arctic ringed seals and polar bears were higher in the east/central Arctic than at more southerly locations. Remarkably high cadmium levels are found in kidney and liver of narwhal (Monodons monoceros) from western Baffin Bay (mean of 63.5 micrograms g-1) and western Greenland waters (median of 39.5 micrograms g-1). Mercury concentrations in muscle of ringed seal and cetaceans frequently exceed 0.5 microgram g-1 especially in older animals. Cadmium concentrations in polar bear liver increased from west to east, while mercury levels were higher in ringed seals from the western Canadian Arctic, which suggests that natural sources of these metals predominate. Studies of temporal trends in OCs in ringed seals and seabirds in the Canadian Arctic indicate PCB and DDT levels declined significantly from the early 1970s to the 1980s. There is a lack of temporal trend data for other OC pesticides as well as for heavy metals and hydrocarbons.(ABSTRACT TRUNCATED AT 400 WORDS)

Publication Types:

Review

Review, Tutorial

PMID: 1514106 [PubMed - indexed for MEDLINE]

[Study of the factors of Cr(III) bioaccumulation on Spirulina platensis]

[Article in Chinese]

Li ZY, Li YG, Guo SY, Li L, Zhang SL.

School of Food & Biological Engineering, South China University of Technology, Guangzhou.

Some factors of Cr(III) bioaccumulation on Spirulina platensis were studied in detail. It was found that the bioaccumulation of Cr(III) on Spirulina platensis involved two steps: rapid adsorption and slow absorption. Chromic(III) compounds with weaker chemical bond had higher bioaccumulation efficiency. Under the same algal cell concentration, Cr(III) bioaccumulation rosed up with Cr(III) concentration. On the other hand, with Cr(III) concentration not changed, the total bioaccumulation of Cr(III) on Spirulina platensis increased with algal cell concentration, but the Cr(III) bioaccumulation on unit algae reduced. The study also showed that Spirulina platensis powder could bioaccumulate more Cr(III) than fresh Spirulina platensis, pH is a quite important factor and more suitable pH for Cr(III) bioaccumulation is 7. It was also proved that Cr(III) bioaccumulation benefited from the increase of temperature and light intensity. Cations had either stimulation or inhibition effects on the Cr(III) bioaccumulation on Spirulina platensis.

PMID: 10883289 [PubMed - indexed for MEDLINE]

The adsorption kinetics of metal ions onto different microalgae and siliceous earth.

Schmitt D, Muller A, Csogor Z, Frimmel FH, Posten C.

Engler-Bunte-Institute, Department of Water Chemistry, Engler-Bunte-Ring 1, Universitat Karlsruhe, 76131 Karlsruhe, Germany.

In the present work the adsorption kinetics of the six metal ions aluminum, zinc, mercury, lead, copper, and cadmium onto living microalgae were measured. The freshwater green microalga Scenedesmus subspicatus, the brackish water diatom Cyclotella cryptica, the seawater diatom Phaeodactylum tricornutum, and the seawater red alga Porphyridium purpureum were the subject of investigation. In most cases the adsorption rate of the metals could be well described by using the equation of the Langmuir adsorption rate expression. Inverse parameter estimation allowed the determination of the rate constants of the adsorption process and the maximum metal content of the algae. The highest values for the rate constant were obtained for Porphyridium purpureum followed by Phaeodactylum tricornutum. High values for the maximum content were obtained for Cyclotella cryptica and Scenedesmus subspicatus. The maximum rate constant was 24.21 h-1 for the adsorption of Hg to Porphyridium purpureum whereas the maximum metal content (0.243 g g-1) was obtained for Zn on Cyclotella cryptica. A comparison of these values with those obtained for the mineral siliceous earth exhibiting low maximum content and high adsorption rates reveals that the mechanism of adsorption onto the algae is a mixture of adsorption and accumulation.

PMID: 11228977 [PubMed - indexed for MEDLINE]

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