Marlene DeMers <mdemers at sunstroke.sdsu.edu> wrote :
> Hi,
> I recently was asked if I knew of any bacteria that "eat"
> other bacteria. I can't think of any, so, I thought I would
> try the newsgroup for any suggestions.
> Thank you in advance.
Bdellovibrio are small motile aerobic bacteria, attacking Gram-negative
bugs. Because they are small, filters may be helpful for their
isolation. Filters of decreasing porosity (0.65 to 0.45 µ) retain most
ordinary bacteria, letting Bdellovibrio go. These spread on bacterial
lawns at the surface of agar, producing clear plaques. These plaques
become wide after several days even when the bacteria have ceased to
grow (contrary to plaques due to cell lysis by phages, that appear
faster).
The predator enters its prey, using several enzymes that make a hole
through peptidoglycans. It grows inside the cytoplasm, within a
structure called bdelloplast. They can grow eventually in open media,
especially mutants forms, provided a bacterial extract or a complex
mixture of aminoacids and other nutrients is present.
Some Bdellovibrio are in turn destroyed by bdellophages.
I have not followed the literature on this subject for long, and I have
only theses references readily at hand :
J.J. Tudor et al. (1990) J.Bacteriol. 172, 2421-2426
K.M. Gray & E.R. Ruby (1990) J.Bacteriol. 172, 4002-4007
You will probably find more recent references quite easily. Good luck.
Sincerely, JP
