Differential Phage Sensitivity of Cell Types in Caulobacter

The genus Coulobacter has been characterized in detail by Poindexter (1964). Because of the simple yet distinct morphological and physiological changes which occur during the life-cycle of this stalked pseudomonad, it may provide a bacterial example for the study of cellular differentiation among lower life forms. The stalked, non-motile Caulobacter cell gives rise to two different cell types upon division, a motile swarmer cell with flagellum and a cell with the original stalk. The stalked cell divides again following the same pattern. However, the motile cell must lose motility and develop a stalk before cell division. It then gives rise to a motile, non-stalked cell and a stalked cell as did its parent. A key to the study of such a system with two distinct growth stages is the effective separation of the two cell types or the elimination of one or the other so that each may be studied separately.