Bacteria Bacteria Bacteria (; common noun bacteria, singular bacterium) are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only about half of the
Leucothrix (bacteria) Leucothrix (bacteria) Leucothrix is a genus of large, filamentous bacteria, which live as epiphytes in marine habitats. "Leucothrix" Oersted, 1844 is the type genus of the family Leucothricaceae Buchanan, 1957, but has also been classified in the family Thiotrichaceae (Gammaproteobacteria). There are two species described, "L. mucor" Oersted, 1844 (type species) and "L. pacifica" Zhang et al., 2015. "Leucothrix" is a large bacterium that forms filaments between 2-3 µm wide and up to 0.5 cm in length. They are usually found as epiphytes on marine plants and algae, but also grow attached to other surfaces like the shells of crustaceans.