Heat-Loving Microbes Offer Clues to Life's Origins

http://news.nationalgeographic.com/news/2004/05/0526_040526_geobacter3.html

John Roach

for National Geographic News

 

Over the past 20 years scientists have warmed up to the idea that the majority of life on our planet lives not on Earth's surface but beneath its crust. The theory has spurred new ideas about life's origins on Earth and where to look for life on other planets.

Earth's crust gets warmer the closer it is to the molten iron-nickel believed to be at our planet's core. One question that scientists who study life beneath Earth's crust face is, at what temperature is it too hot for life to survive?

Since scientists believe Earth at one point was mostly molten, the answer to the question may shed light on how early life could have first evolved on our planet.

   "If Earth had to cool to a certain temperature at which life was possible, maybe the high-temperature life could have existed that much sooner," said Derek Lovley, a microbiologist at the University of Massachusetts, Amherst.

Much of this life beneath the crust, which scientists refer to as biomass, are microbes that use hydrogen and minerals like iron to get energy from food sources in the same way that humans use oxygen to obtain energy from our food.

Lovley is at the forefront of research into such microbes. He has discovered dozens of different species, including Strain 121, a microbe that grows at 121𨰫 Celsius (250𨰫 Fahrenheit)—the highest temperature currently known for life.

The ability to grow at 121𨰫 Celsius is significant because for over a century it has been the temperature used to sterilize medical equipment. Scientists thought that such temperatures would kill all life-forms.

"It's kind of a benchmark," Lovley said. "This is like breaking the four-minute mile."

Strain 121, which goes dormant at temperatures below 80𨰫 Celsius (176𨰫 Fahrenheit), lives in environments known as hydrothermal vents on the ocean floor. The vents spew hydrogen- and mineral-rich hot water from deep in the Earth's crust to the surface.

For several years scientists have known that other microbes survive in and around hydrothermal vents at temperatures above 100𨰫 Celsius (212𨰫 Fahrenheit). Strain 121 just "opens that window where life can exist a little bit wider," Lovley said.

Jack Farmer, an astrobiologist at Arizona State University in Tempe, said that opening this window for life on Earth expands the potential for life to develop and persist elsewhere in the solar system and beyond.

"As the upper temperature limit for life has increased, new opportunities for habitable environments have opened up, and subsurface hydrothermal environments are among the most important," Farmer said.

"Poor Man's Drill"

John Delaney, a marine geologist at the University of Washington in Seattle, led the expedition that brought to the surface the chunk of hydrothermal vent from which Strain 121 was isolated.

Delaney said that examining such environments gives researchers a snapshot of what life is like deeper in the Earth's crust, where temperatures are higher. "Our way of doing it was a 'poor man's drilling program,'" he said.

The expedition team used a remotely operated submarine to cut out and bring to the surface a chunk of hydrothermal vent from the Juan de Fuca Ridge, which lies about 200 miles (322 kilometers) offshore from Washington's Puget Sound and nearly 1.5 miles (2.4 kilometers) deep in the Pacific Ocean.

The seafloor at the Juan de Fuca Ridge is cold, about 2𨰫 Celsius (36𨰫 Fahrenheit). But down beneath the seafloor the temperature warms gradually until, eventually, it is scalding hot.

"If you telescope those conditions by having hot water coming out along a fissure it will build a sulfide chimney," Delaney said. "And this sulfide chimney is very cold on the outside—two or three degrees—but on the inside it might be as much as 300𨰫 centigrade."

A chunk of one of these chimneys, or hydrothermal vents, is what Delaney and his team brought to the surface.

"We figured we would see different kinds of microbes in the wall as it got to hotter and hotter temperatures, and [that] pretty soon microbes wouldn't be there 鞱 [which would] indicate a limit to life under those conditions," he said.

Limits and Origins

Microbes like Strain 121 that live in environments lacking organic carbon are known as archaea, which literally means "ancient." Archaea are genetically different from seemingly similar bacteria, which need organic matter and photosynthesis to survive.

The discovery of Strain 121 bolsters the theory held by some scientists that Earth's first life-forms were archaea that could thrive at high temperature via chemical reactions with hydrogen and iron.

"They appear to be the branches closest to what is the last common ancestor of existing life," Lovley said. "All are hyperthermophiles that live at high temperatures."

Early in Earth's history, according to Delaney, volcanic eruptions occurred on the ocean floor as the planet's core separated from its crust. These eruptions could have allowed the mixing of hydrogen and minerals like iron and sulfur, upon which microbes could thrive.

"That may be one of the paths the origins of life takes," Delaney said. If that's the case, he added, then studying hydrothermal vents is a step in the process of understanding how the dynamics of such a system might work.

And understanding how such a system works on Earth may help in the search for life on other planets.

Farmer, the Arizona State University astrobiologist, said, "At the bottom line, hydrothermal systems were widespread in the early solar system and are thought to still be present in the subsurface of many other solar system objects, like Mars, Europa, and even the interiors of large asteroids."

 

            I choose to include this article in my journal because it relates to current events and issues. Not a while ago, there was a space exhibition to Mars. They did not find life on the planet. However, if live was possible IN the planet, it would be a great leap in science.

            This article is basically talking about the microbe known as Strain 121 and how it can survive in temperatures near 121。Celsius. They are found in hydrothermal vents on the ocean floor, where hot water filled with mineral are released. If these microorganisms can strive in these conditions, its possible that they can nearer to the core of the Earth, where it is much hotter.

 

Neandertals Were Fully Developed by Age 15, Experts Say

 

Hillary Mayell

for National Geographic News

April 28, 2004

 

Neandertals may have matured much earlier than modern humans—perhaps by as young as 15 years old, as opposed to 18 to 20 for modern humans, a team of scientists reports.

Researchers Fernando V. Ramirez Rozzi and José Maria Bermudez de Castro compared fossil teeth of Neandertals, anatomically modern humans, and two earlier species in the Homo genus (Homo antecessor and Homo heidelbergensis).

The researchers' results indicate that Neandertal growth patterns differed significantly from that of modern humans.

   "Surprisingly, Neandertals were characterized by having the shortest period of dental growth," they write in the April 29 issue of the science journal Nature.

The difference in maturation rates is further evidence that Neandertals were a distinct species and that they were not our forefathers, the authors conclude.

"It's another piece of evidence that Neandertals were biologically very different than modern Homo sapiens, different enough to be a different species," said Gary T. Schwartz, a paleoanthropologist at Northern Illinois University. "Because they're growing so fast in a fundamentally different way, it essentially precludes them from being our ancestor."

Others disagree. Erik Trinkaus is a paleoanthropologist at Washington University in St. Louis. He argues that there are no established criteria or data for determining at what point different growth rates indicate different species.

The authors also do not take into account normal variation in growth rates, which are influenced by both genetic makeup and environmental factors, Trinkaus said.

"I think they grossly overinterpret the data," Trinkaus said. "A 10 or 15 percent difference in the rate of maturation is well within the normal variation of modern population."

"Even if Neandertals are growing a little faster, in terms of behavior, age of reproduction, and demography, I'm not convinced it would make a big difference," he said.

Tooth and Brain

A surprising amount of information can be gleaned from teeth. The rate at which teeth grow is linked to diet, brain size, gestation length, age of reproduction, and longevity.

"The really wonderful property of teeth is the fact that how they grow mirrors how organisms grow. You're able to reconstruct whole aspects of life history," Schwartz said.

Paleontologists define adulthood by when the last permanent tooth—the wisdom tooth—emerges.

"When you look at the modern human growth profile, humans are uniquely long-lived for apes," Schwartz said. "It takes us a long time to reach adulthood, and then we live for a long time."

Scientists consider modern humans' prolonged pattern of growth and maturation a major step forward in human evolution, because it allows extra time for learning.

In Neandertals the entire process was fast-forwarded. Their wisdom teeth emerged at around 15 years of age, according to Ramirez Rozzi, a researcher with Dynamique de l'Evolution Humaine (Dynamics of Human Evolution) in Paris, and Bermudez de Castro, of the Museo Nacional de Ciencias Naturales (National Museum of Natural Sciences) in Madrid.

Jay Kelley, a paleoanthropologist at the College of Dentistry at the University of Illinois in Chicago, wrote an accompanying commentary to the Nature article. He thinks the conclusion that Neandertals reached adulthood by 15 might be a bit of a stretch.

"I think the study shows a clear pattern difference that probably does have some implications for how Neandertals grew up," Kelley said. "I'm much more cautious about the specific conclusions about just how fast Neandertals grew up. Relationships between traits like brain size and teeth growth rate are fairly broad and have a lot of variation to them."

Long-Lived Apes

The authors say the results were somewhat surprising, because the growth and development of teeth and brains are very tightly correlated, and on average, Neandertals had larger brains than modern humans.

Earlier studies suggested that larger brain size drove the prolonged growth pattern. The authors suggest that the accelerated maturation rate resulted from high adult mortality rates. They also suggest Neandertals must have had a high-calorie diet and a fast metabolism to fuel such rapid growth.

"That conclusion is probably not far off in terms of life-history theory," Schwartz said. "Earlier maturation means earlier reproduction, and if you're a population at risk, then it behooves you to reproduce earlier."

The issue of whether Neandertals were direct ancestors of modern humans has basically reached a consensus, Trinkaus said.

Neandertals evolved in Europe and were a highly successful species, surviving in harsh environments for a quarter of a million years. Modern humans evolved in Africa around 130,000 years ago. They spread out of Africa to populate the rest of the world around 50,000 years ago.

            I found this article interesting because it relates to the evolution of humans. It is interesting how different scientists' opinion differ. While one side believes that Neanderthals are not ancestors of modern humans, another side disagrees.

            This article mainly shows that the Neanderthals develop at a faster rate than other species of "man". Neanderthals finish growing their teeth [wisdom teeth] at the age of 15, which means they are adults. This shows that their live span was much shorter, and they had more danger of the species dying out. This also gives some clues about their bodies and feeing habits [high-calorie diet and high metabolism]. Using this discovery, some scientists say that this is just another evidence to prove that Neanderthals are a separate species from the Homo Sapiens. Others say that just because Neanderthals mature at a fast rate doesn't disprove that they are our ancestors.

Snake Venom May Slow Cancer Growth, Studies Hint

 

Jennifer Hile

National Geographic Channel

June 1, 2004

 

Preliminary research shows a natural compound in some snake venoms may prevent the growth of cancerous tumors, potentially transforming one of nature's deadliest toxins into a curative agent.

"Snakes use venom to alter biological functions, and that's what medicine does too," explained John Perez, director of the Natural Toxins Research Center at Texas A&M University-Kingsville. "This is why venoms have always been of interest to medical researchers."

   Today roughly a dozen diagnostic tests and drugs are derived from snake venom, according to Zoltan Takacs, a toxinologist (natural-toxins scientist) and herpetologist based at the Yale University School of Medicine in New Haven, Connecticut.

ACE inhibitors, a class of drugs used to treat high blood pressure and other cardiovascular disorders, were developed from the venom of a Brazilian snake. Scientists anticipate that this is just the beginning.

Of the nearly 3,000 species of snakes in the world, about 650 are venomous. Ten of the most deadly live in Australia, making it a logical base for new experiments.

"We knew Australia could be a rich source of drugs because there are so many venomous creatures here," said Tony Woods, a biologist at the University of South Australia in Adelaide. Woods is co-leader of a project to investigate whether the toxins in venom can be used to destroy blood vessels that feed cancerous tumors.

The Power of Nature's Toxins

Venoms are exquisitely complex, composed of as many as a hundred different peptides, enzymes, and toxins. Not only are the venoms of every snake species different, there are also subtle variations within each species.

"There are differences between [venoms of] juveniles and adults, and even among different geographic regions," Takacs said. "These differences may be due to different evolutionary pressures, like different ancestry, prey, and environments."

The variations between venom types and the number of venomous snakes worldwide create a rich molecular hunting ground for researchers, like Woods, seeking to design new drugs.

"A tumor is made of tissue," Woods said. "Like tissue in any part of the body, if you can prevent it from developing a blood supply, or interfere with that supply, then you will have an effect on the growth of that tissue."

Woods is working with Michael Venning, a pharmacologist at the University of South Australia, and graduate student Emma Bateman. Peter Mirtschin, a toxinologist at Venom Supplies in Tanunda, South Australia, is providing the venom directly from the snakes.

Woods's group has found a compound in snake venom that disrupts endothelial cells, which line the inner surface of blood vessels. "It causes the cells to separate from one another, which kills them," Woods said. "When that happens, the function of the blood vessel is inhibited, preventing or at least interfering with blood flow to the tumor [effectively starving it of nutrients]."

Woods will not specify which snake venoms his team is studying, because the compounds have not yet been patented.

The Cure That Doesn't Kill

The advantage of these venom-derived toxins is that they seem to act only on certain types of cells.

Chemotherapy and many other drug treatments do not distinguish between tumor cells and other healthy cells, causing debilitating side effects. But natural toxins have evolved to impact very specific targets.

"We believe the cells that line blood vessels in tumors are different in subtle ways from similar cells elsewhere in the body, because they are exposed to different stimulation and chemicals," Woods said. That means toxins inhibiting tumor blood vessels may not effect surrounding healthy cells, which would theoretically leave patients using these toxins feeling better than those who go through chemotherapy.

Woods anticipates that he will begin testing the venom-derived toxin in animals within the year. Those results will reveal whether the drug is suitable for human clinical trials.

 

                        After reading this article, I felt very uplifted. In modern medication, cancer is still a serious disease that causes death. Right now, there are technologies like chemotherapy to be treat tumors, it is not a direct cure and it also causes many side effects to the patient.

            The focus of this article is on snake demons. Snake venoms are very diverse, each species develop different venoms and within species there are slight variations. Venoms contain natural toxins and some have already been used medically. "Snakes use venom to alter biological functions, and that's what medicine does too. This is why venoms have always been of interest to medical researchers." as John Perez put it. In particular, the scientists are working on developing a toxin that treats cancer. They explain that blood vessels in tumors are slightly different than other healthy ones. Because of this and how venoms differentiate so much, it is possible to develop a toxin that targets only blood vessels of tumor tissue. If successful, blood flow to the tumor would be interfered or cut off which would starve the tissue of nutrients.

 

            During my volunteering in Science World, I got a change to take a look at the films in the IMAX theater. The film Jane Goodall and the Chimpanzees was very well done. As the title suggests, it is about chimpanzees. I found it very interesting because normally, I would not have a chance to see and learn about these animals and their behaviour from a first-person narrator. It was a good documentary while grabbing the audiences’ attention without making them feel bored; the film is enjoyable to children and adults. Although a lot of the film captured the playfulness of the chimps, there were serious facts that I did not know before. I found the behaviour of them to be most exciting, some resembles primitive humans.

            Chimpanzees live in groups and form societies. There is always a male [usually the stronger one] that dominates and leads the group. Tools, the chimpanzees were smart enough to use tools to obtain their food. The one portrayed in the film was using a thin branch to obtain ants inside of logs. What's more interesting is that the use of tools is passed down to later generations. This is proven by the variety of tools used by the same species of chimps located in different areas. Although the same resource is available in other areas, the chimps have not learned to use that technology. What I was most surprised at was how these creatures were capable of "war". To defend their territory, they would fight to the death with other species and even their own. This is different from a couple of animals fighting; this was a large group and somewhat organized battle between the chimpanzees and the invaders that are threatening their family and home. After watching that part, I couldn't help but to think how that resembles human beings.

 

Flu During Pregnancy Linked to Schizophrenia

Yahoo! News   Fri May 7, 5:25 PM ET

 http://story.news.yahoo.com/news?tmpl=story&ncid=1408&e=20&u=/nm/20040507/hl_nm/flu_pregnancy_dc&sid=95862975

 

By Anthony J. Brown, MD

 

NEW YORK (Reuters Health) - Children born to women who contract the flu during pregnancy appear to have an increased risk for schizophrenia later in life, new research suggests.

Prenatal influenza exposure may account for about 14 percent of schizophrenia cases, according to the findings presented here this week at the annual meeting of the American Psychiatric Association.

"This is the first time that this association has been shown using" blood tests that confirmed influenza infection during pregnancy, lead author Dr. Alan S. Brown, from Columbia University in New York, told Reuters Health. "It provides what I think is the strongest evidence to date linking (prenatal) influenza exposure with schizophrenia."

Previous studies investigating this topic have either relied on maternal surveys to determine prenatal influenza exposure or have simply correlated an earlier influenza outbreak with schizophrenia risk in a defined population, Brown noted.

In the present study, stored maternal blood samples from 64 patients with schizophrenia and 125 subjects without the disease were tested for antibodies to determine if flu exposure had occurred during pregnancy.

First trimester exposure to influenza raised the risk of schizophrenia by sevenfold, the authors report. Exposure at any time during the first half of pregnancy increased the risk threefold.

"I was a little surprised that we observed an effect during both middle and early pregnancy," Brown said. In previous studies, the effect has largely been confined to the middle period, he explained.

Exactly how prenatal influenza exposure may lead to schizophrenia is unclear, but it could involve direct effects from the virus or indirect effects involving chemicals that are released in response to the virus, Brown noted.

 

            When I first read this article, I was quite shocked. Who would have thought prenatal influenza would be linked to schizophrenia?  Although I do not know much about schizophrenia, I do know that it is a mental disorder relating to the distortion of reality. I never would have thought a flu virus affecting a mother would increase the chance of a mental disorder of her child.

            Although how prenatal influenza links to schizophrenia is unclear, it is proven that is does increase the chance of the mental disorder. An experiment was executed with maternal blood samples of patients with schizophrenia and samples of those without. The results show that influenza increased the risk of schizophrenia by three times during the beginning of pregnancy and seven times during the middle of pregnancy. Expert says it might be the effect from the virus or chemicals in response to the virus.

 

Study: Obese Kids May Develop Diabetes

Yahoo! News  Thu Jun 3, 7:18 AM ET  

http://story.news.yahoo.com/news?tmpl=story&cid=541&ncid=751&e=6&u=/ap/20040603/ap_on_he_me/fit_obesity_children

 

By STEPHANIE NANO, Associated Press Writer

 

A study of very obese children suggests half may have a worrisome cluster of health conditions that increase their risk of developing diabetes and heart disease at an early age.

Researchers at Yale University School of Medicine said their findings suggest that this combination of health ills, a condition called metabolic syndrome, is more common among children and adolescents than previously thought and increases with the level of obesity.

"Obesity is not just a cosmetic issue. It's a big problem because you open the door for serious, chronic complications," said Dr. Sonia Caprio, who runs the pediatric obesity clinic at Yale.

Caprio said metabolic syndrome increases these youngsters' risk of early development of type 2 diabetes and heart disease — problems usually associated with middle age.

Within two years, eight of 34 children with metabolic syndrome developed type 2 diabetes, according to the study in Thursday's New England Journal of Medicine (news - web sites).

"This is a yellow flag and a warning for public health officials and education systems to focus on reducing childhood obesity," said Dr. Sethu Reddy, an endocrinologist at The Cleveland Clinic.

The conditions generally used to define metabolic syndrome are obesity, high blood pressure, high blood sugar, high triglycerides and low HDL, the good form of cholesterol. Anyone with three of the five conditions is considered to have metabolic syndrome, and about a quarter of adults have it.

The researchers tested 439 children and adolescents — 244 who were moderately obese and 195 severely obese. Also tested were 51 of their siblings who were overweight or lean.

Metabolic syndrome was found in 50 percent of the severely obese and 39 percent of the moderately obese but not in any of their siblings. After obesity, high blood pressure was the most common condition.

An earlier study, based on a 1988-94 national health survey, found that 29 percent of obese adolescents had metabolic syndrome. Since then, the number of overweight children has increased from 11 percent to 15 percent of those 6 to 18 years old.

Seventy-seven of the Yale participants were checked again about two years later. Twenty-four of 34 still had metabolic syndrome, and eight had developed type 2 diabetes. The syndrome developed in 16 of the 43 children who did not initially have it.

"I've been in the field for 20 years. What I'm seeing now, I've never seen before," said Caprio, adding that it is not uncommon for a teen to weigh 200 or 300 pounds.

 

            Obesity seems to have become a serious problem in our modern society. With all the fast food, candy and sugary beverages available, obesity has become more common. These tasty but not nutritional foods are usually the cause. Obesity is not healthy and often causes diseases.

            This article talks about how obesity affects children and teens. These obese children are in danger of developing heart diseases and diabetes in an early age. These are usually problems of middle-aged people, but these are problems of overweight children too. Many obese children have developed metabolic syndrome (obesity, high blood pressure, high blood sugar, high triglycerides and low HDL, the good form of cholesterol.), which results in serious health issues.