Do Bacteria Age?

A microcolony of E. coli developing on agar from
three neighboring cells. ASM Microbe Library.
Credit: J. Shapiro and C. Hsu

The question arises: do bacteria get old? Of course they do, their being young immediately after cell division and old when they are about to divide again. But, in a different sense, do they age over many generations? Or, as is commonly assumed, does binary fission obliterate any difference between sibling cells? The question has been studied in detail by Eric Stewart and colleagues, with the surprising answer that conventional wisdom is wrong. There is a difference between the growth rates of  "old" and "new" bacteria. Subtle, but there. This question, and a related one regarding the percentage of viable cells in a growing culture, has been discussed in a highly satisfying manner in a series of posts on John Dennehy's illuminating blog, Evilutionary Biologist. I had a small hand in it, as this repartee reminded me of an unassuming and unpublished experiment I did one hundred years ago (or so it seems).

Comments

[Biochem student]

Bacteria have a circular chromosome which is replicated completely every time it divides (unless there are mutations). However, Human chromosomes are linear and therefore can not be replicated fully by a 5' to 3' polymerase. We require telomerase to add extra telomers to the end of the chromosome so that it does not shorten with each generation. However, as we age telomerase is expressed in smaller quantities. Our cells age with passing generations because telomers are not added and our chromosomes shorten. Bacteria don't age because their chromosome is circular and can be completely replicated by a 5' to 3' polymerase.

[Amin talebi bezmin abadi]

We have more than billions of cells in our bodies,. They divide and grow up and die finally, Bacteria are basically similar to our cells, Why not!? it is not unusual that we think they can be old or that they age!
We must respect them ! as important member of our great earth !

Amin TALEBI
TARBIAT MODARES UNIVERSITY

[woan]

Sounds good.Can we just think about human cells.When we were baby,our cells are little.When we grow up,our cells get big and in large amount.So,didn't our cells divided from one cell to two,generation and generation,it becomes more and big.
But we don't think our age is the time that one cell divide into two.So,why can we define the bacterias' age as the time that one divide into two?Cause they just have one cell?