Caulobacter crescentus

Caulobacter crescentus is a Gram-negative, oligotrophic bacterium widely distributed in fresh water lakes and streams. It plays an important role in the carbon cycle.

Caulobacter is an important model for study of the regulation of the cell cycle and cellular differentiation. Caulobacter daughter cells are very different from each other. One is a mobile "swarmer" cell that has a flagellum for swimming. The other, called the "stalked" cell has a long tubular stalk structure protruding from one pole that has an adhesive holdfast material on its end. The stalked call can adhere to surfaces. Chromosome replication and cell division only occurs in the stalked Caulobacter cells. Often surviving in nutrient-poor environs, Caulobacter crescentus is a Gram-negative bacterium ubiquitous in fresh water, soil, and sea water. C. crescentus exhibits a dimorphic life cycle that most likely provides an advantage in such competitive environments. The stalk cell can attach to a surface, while the swarmer cell can search for nutrients. The adhesive material of the holdfast has been reported to be one of the strongest natural glues.

Caulobacter Aging
Caulobacter was the first asymmetric bacterium shown to age. Reproductive senescence was measured as the decline in the number of progeny produced over time. A similar phenomenon has since been described in the bacterium Escherichia coli, which gives rise to morphologically similar daughter cells.