Bdellovibrio Requirements 2

Bdellovibrio

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Life Cycle and Development

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Food Preservation

Temperature:

Bdellovibrio have been found to be mesophilic, normally found in the range of 25-35 degrees Celcius (Varon and Shilo, 1968). It appears that the optimal conditions for growth are more between 28 and 30 degrees, and at temperatures above 37 degrees and below 10 degrees we see poor growth (Burnham and Conte, 1988). With regards to surface associations, decreased temperatures caused decreased associations, and at the point of 6 degrees Celcius, the bacteria is not found attached at all (Williams and Kelley, 1995). Some psychotropic strains of Bdellovibrio have been found, which are active at temperatures below 10 degrees Celcius, however these strains are found to have increased activity when introduced to temperatures above 20 degrees (Fratamico and Whiting, 1994). Host composition may play a role in the temperatures that are tolerable for any given strain, as lipid membrane derivation is directly from the host.

Requirements

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Other considerations:

- Bdellovibrio is obligately aerobic, though it seems to have a preference for low oxygen environments, which may reflect an adaptation to intracellular growth (Seidler et al, 1969).

- Recent findings show that bacteria that have paracrystalline protein surface layes (S layers) may have increased resistance to attack by Bdellovibrio, which may require prey without this layer at all in order to survive (Koval and Hynes, 1991).

- Evidence has shown that only certain serogroups of Escherichia and Salmonella are susceptable to attack, indicating a requirement for certain receptor sites on the prey wall (Fratamico and Whiting, 1994). Other studies show that increased attachment can occur on prey with no O-specific side chains and also have a complete R-core, indicating the lipopolysaccharides may be involved in the attachment receptor (Varon and Shilo, 1969).