Proteobacteria

Proteobacteria (pronounced: pro-tee-o-bak-tee-ree-uh) is a major group (phylum) of bacteria. They include a wide variety of pathogens, such as Escherichia, Salmonella, Vibrio, Helicobacter, Yersinia, Legionellales, and many other notable genera.

Etymology

The name Proteobacteria comes from the Greek god Proteus, who could change his shape, because they include a wide variety of cells. In the system of Carl Woese, it is placed in the Bacteria "domain".

Characteristics

Proteobacteria are Gram-negative bacteria with an outer membrane mainly composed of lipopolysaccharides. Many move about using flagella, but some are non-motile or rely on bacterial gliding. The latter include the myxobacteria, an order of bacteria that can aggregate to form multicellular fruiting bodies. Also, a wide variety in the types of metabolism exists. Most members are facultatively or obligately anaerobic, chemoorganotrophs, and heterotrophic, but numerous exceptions exist.