aulobacter crescentus isn't much to look at. When you peek through a microscope at 630-times magnification, the freshwater bacteria appear as a swarm of little gray, kidney-shaped creatures flitting about in the drop of medium between slide and coverslip.
Sometimes, though, one member of the gram-negative crew will adhere to the nearest surface, exchanging its flagellum for a stalk and producing what is considered to be one of nature's strongest glues. Gradually, other individual cells will glom onto the Caulobacter stalk cell, often sharing each other's points of adhesion to form rosettes—flower-like shapes in which the bacteria extend out like petals—that, under certain conditions, expand to become biofilms.
The cells' penchant for adhesion is distinctly—and surprisingly—regulated by light. Caulobacter is a chemotrophic organism, that is, it gets its energy from electron chemical reactions such as oxidation, not from sunlight. Biologists using it as a model organism for ...
