Phospholipid-derived fatty acids microbial classes when in fact those PLFAs are present in a broad range of life forms. Phospholipids can occur in many biological classes (such as in plant roots, fungi, as well as in soil bacteria), so care has to be taken in over-assigning PLFA biomarkers to the wrong class. Even though phospholipids occur in many different life forms, the fatty acid side chains between differing life forms can be quite unique. Polyunsaturated fatty acids ("e.g." 18:3 ω3c) are found in plants, algae and cyanobacteria, but are often not present in bacteria. Monounsaturated fatty acids (particularly at the omega-7 position), odd-chain
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.