Do All Bacteria Age?

Nature reports on an elegant photographic experiment that has detected the signs of aging (or senescence) in certain bacteria, once thought to be immortal. "E. coli divides down the middle, giving each daughter cell one newly regenerated tip. But the cell's other tip is passed down from its mother, or grandmother, or some older ancestor. The bacteria inheriting the older end reproduced 1% more slowly than their counterparts with each cell division ... Discovering how to monitor bacterial lifespan may help us understand the genes that control human ageing, which are implicated in everything from weakened immunity to sagging skin."

Link: http://www.nature.com/news/2005/050131/full/050131-6.html