Microbiologists
in South Korea report that the bacterium Chromobacterium
piscinae produces cyanide when under attack from Bdellovibrio bacteriovorus HD100, a microbial predator found in
rivers and soils that ingests its prey from the inside out. The researchers
found that the prey produced levels of cyanide high enough to inhibit, but not
kill, the B. bacteriovorus HD100.
Experiments
showed that C. piscinae produced the
protective cyanide in a nutrient-rich broth. In a medium devoid of nutrients,
it didn't produce the cyanide and was consumed. The researchers suspect that
the bacteria likely uses some ingredient in the broth to produce the cyanide.
That observation implies that a bacteria's defenses may depend on location --
and, more generally, that bacteria may harbor protective mechanisms that are
triggered in some environments, but not in others.
Studying
such mechanisms may lead scientists to better understand how some pathogenic
bacteria protect themselves against antibiotics, says microbiologist and study
leader Robert Mitchell. His lab at the Ulsan National Institute of Science and
Technology, in South Korea, focuses on understanding how microbial prey protect
themselves from predators. They are investigating how bacterial predators like B. bacteriovorus HD100 might be
optimized as "living antibiotics" that can target bacterial
pathogens.
The
study suggests microbes may have means for resisting predation that only show
up in certain environs.
See:
Posted by Dr. Tim Sandle