crescentus

Caulobacter crescentus, commonly referred to as crescentus, is a Gram-negative, aquatic bacterium in the genus Caulobacter. It is a widely used model organism for studies of bacterial cell cycle, differentiation, and development due to its well-characterized life cycle and genetic tractability.

In its life cycle, C. crescentus produces two distinct cell types through asymmetric division: a motile, flagellated swarmer cell and a sessile, stalked cell bearing a prosthecate extension called a stalk with a holdfast for surface attachment. Swarmer cells are replicationally inert and must differentiate into stalked cells before DNA replication and cell division can proceed.

Habitat and ecology: It is commonly found in freshwater environments, where it forms biofilms on submerged surfaces and participates in nutrient cycling. The holdfast helps the bacterium attach firmly to substrates in flowing water.

Genomics and research significance: The genome has been sequenced, and the organism serves as a paradigm for understanding polar development, cell polarity, and the bacterial cell cycle. Its straightforward genetics and life-cycle transitions make it a staple in microbiology and systems biology research.

Applications and relevance: Beyond basic science, C. crescentus informs studies of adhesion, prosthecate organelle biology, and synthetic biology. It remains a reference model for comparative studies across Alphaproteobacteria and for teaching about cellular differentiation and regulation.