Polarity, asymmetry and aging: are there Yayatis among bacteria?

Abstract

Bacteria have been shown to age. In an exponentially growing population some cells progressively slow down and stop dividing1 . This is thought to be due to asymmetric damage segregation in which old pole cells retain damaged components and the new pole cells receive newly synthesized components2 . Polarity implies functional asymmetry with a predefined direction with or without morphological difference. Cellular polarity and division asymmetry are common to yeast, bacteria and stem cells of multicell organisms3 . A number of processes in bacteria, including formation of endospores, flagella, stalks or buds show clear polar biases.