Rice study: Bacterial decision circuit makes use of circular
chromosome
(July 10, 2015) In
spore-forming bacteria, chromosomal locations of genes can couple the DNA
replication cycle to critical, once-in-a-lifetime decisions about whether to
reproduce or form spores. The new finding by Rice University bioengineers and
colleagues at the University of California at San Diego and the University of
Houston appears this week in the journal Cell.
Like most microorganisms, Bacillus subtilis bacteria are
single-celled creatures with one goal: to reproduce by making copies of
themselves. But survival isn’t always that simple. For example, when food gets
scarce, B. subtilis must decide between two possible paths: shut down, form a
dormant spore — a process called “sporulation” — and wait for better times or
split into two cells and gamble that there is enough food for at least one more
generation.
“The decision about whether to form a spore and when is a
very important one for B. subtilis,” said Oleg Igoshin, associate professor of
bioengineering at Rice and one of the lead researchers on the new study. “If
the organism waits too long, it can starve before it finishes transforming into
a spore. If it acts too early and forms a spore too soon, it can be overwhelmed
and out-reproduced by competitors.”