A genus of Gram-negative bacteria not assigned to any taxonomic family. The cells undergo a life cycle that is unusual in bacteria. Mature cells are straight or curved rods with a stalk-like extension at one end. The cell is attached to rocks, plants, other cells, etc. by means of an adhesive holdfast at the tip of the stalk. Asymmetric division of a mature cell leads to the formation of a motile (flagellated) immature cell; this subsequently attaches to a substrate, loses its flagellum, and develops a stalk, thus becoming a mature cell. These bacteria are aerobic chemo-organotrophs. They are found, for example, in soil and in oligotrophic fresh water.
Subjects: Plant Sciences and Forestry.