|The marine bacterium Vibrio harveyi glows
when near its kind. This luminescence, which results from biochemical reactions,
is part of the chemical communication used by the organisms to assess their
own population size and distinguish themselves from other types of bacteria.
But V. harveyi only light up when part of a large group. This communication,
called quorum sensing, speaks for itself here on a lab dish, where more
densely packed areas of the bacteria show up blue. Other types of bacteria
use quorum sensing to release toxins, trigger disease, and evade the immune
system. Courtesy of Bonnie Bassler, a microbial geneticist at Princeton
University. Featured in the September 20, 2005, issue of Biomedical Beat.
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