Bacterial cells are singularly long-lived. They keep dividing for what seems like forever. But because they are made of biochemicals, their DNA and proteins should suffer damage similar to what any other cell endures, including animal cells. What keeps bacterial cell components from wearing down?
Microbiologists have been trying to find out how these single-cell organisms handle chemical damage, which relentlessly accumulates due to friction and uncontrolled chemical reactions. So far, the results have been confusing, but a new analysis appears to have confirmed that bacteria have a remarkably well-engineered damage-reduction program.
University of California, San Diego biologist Lin Chao led a computer analysis of prior experiments.1 His team’s work, published in Current Biology, cited a 2005 study showing that bacteria do age and that the cells do accumulate damage. But a subsequent study clearly showed no evidence of aging in the same bacteria species. Chao’s analysis asserts that both are true.
His team proposed that when one bacterium divides into two cells, more of the damaged biochemicals end up in one than the other of the daughter cells. After many generations, a single population of bacteria ends up as a mixture in which cells filled with accumulated damage live side-by-side with “rejuvenated” cells.2
Chao said in a university press release:
So for a single celled organism that has acquired damage that cannot be repaired, which of the two alternatives is better—to split the cellular damage in equal amounts between the two daughters or to give one daughter all of the damage and the other none?2….
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