He said that E. coli, for instance, shows dramatic changes in behavior even within its comfort zone of about 30 to 41 degrees Celsius (86 to 105 degrees Fahrenheit).
"For every 10 degrees Celsius increase in temperature, there's about a doubling in the cell cycle speed," Bennett said.
Among biological processes, there's a notable exception: circadian clocks that keep a steady beat despite the temperature. "We have genetically controlled clocks that help us determine the time of day and coordinate our response to the day-night cycle, changing hormone levels and our alertness. And we're not the only organisms that have them," he said.
"Plants and fungi and even some bacteria that do not have internal temperature regulation also have circadian clocks. For those organisms, it's very important that the period of their circadian clocks remains the same regardless of temperature changes. Your crops, no matter whether it's hot or cold, always keep to the same day-night cycle."
But circadian clocks are also biochemical. "As it gets colder, circadian clocks should slow down, and as it gets warmer, speed up, but they do not," he said. "It's been a mystery as to why that doesn't happen."
Bennett suspected the clocks take their cues from a combination of cellular feedback loops and temperature-sensitive proteins. "Instead of looking at circadian clocks in humans or plants, however, we decided to build a system from the ground up," he said.
His research group started with a synthetic gene oscillator that was built to run in E. coli. Then, by altering a single amino acid of a key protein LacI, the lactose repressor the researchers made that protein temperature-sensitive and provided the synthetic clock a guide to compensate for changing conditions.
Bennett noted in the paper that en
|Contact: Jeff Falk|