FIG. 5.

The life cycle of Caulobacter crescentus. (a) Motile swarmer cell. (b) The swarmer cell settles down, loses its flagellum and pili and forms a stalk in their place. (c) As the cell grows, it begins to replicate DNA and assembles flagellar precursors at the distal pole. (d) Prior to division, the distal pole sprouts a flagellum and motility is activated. (e) The progeny stalked cell initiates a new round of replication, while the progeny swarmer cell swims off. (After Ausmees and Jacobs-Wagner [4], with permission of the publisher.)