Experiment Turns Up The Heat On Natural Selection, Reveals New
Details Of An Evolutionary Mechanism Thu, 06/17/2010 - 8:23am
In addition to being a well established resident of the human
digestive tract, Escherichia coli is at home in the lab. It is a
model organism as important to biological research as brewer's
yeast, the fruit fly, and the mouse. Having evolved for life at
our body temperature of around 37 degrees C., wild-type E. coli
can be cultivated in the laboratory at temperatures up to but
not beyond 44 to 46 degrees C. Pushing the upper temperature at
which E. coli could grow to 48.5 degrees C. does not approach
the level of heat resistance found in thermophile species, but
what this experiment required was a distinct and significant
redefinition of "extreme" for E. coli.  To achieve that, Dr.
Jeannette Winter and colleagues at the Technische Universitaet
Muenchen (TUM) founded three lines of E. coli bacteria from a
common ancestor and propagated them under heat stress for
hundreds of generations