Phytoplasmas are obligate intracellular parasites of plant phloem tissue and of the insect vectors that are involved in their plant-to-plant transmission. Phytoplasmas were discovered in 1967 by Japanese scientists who termed them mycoplasma-like organisms. Since their discovery, phytoplasmas have resisted all attempts at in vitro culture in any cell-free medium; routine cultivation in an artificial medium thus remains a major challenge. Phytoplasmas are characterized by the lack of a cell wall, a pleiomorphic or filamentous shape, a diameter normally less than 1 μm, and a very small genome.
Mollicutes is a class of bacteria distinguished by the absence of a cell wall. The word "Mollicutes" is derived from the Latin mollis, and cutis. Individuals are very small, typically only 0.2–0.3 μm in size and have a very small genome size. They vary in form, although most have sterols that make the cell membrane somewhat more rigid. Many are able to move about through gliding, but members of the genus Spiroplasma are helical and move by twisting. The best-known genus in the Mollicutes is Mycoplasma. Colonies show the typical "fried-egg" appearance.
Mycoplasmataceae is a family of bacteria in the order Mycoplasmatales. This family consists of the genera Mycoplasma and Ureaplasma.
Acholeplasma are wall-less bacteria in the Mollicutes class. They include saprotrophic or pathogenic species. There are 15 recognised species. The G+C content is low, ranging from 26 - 36% (mol%). The genomes of Acholeplasma species range in size from 1.5 to 1.65 Mbp. Cholesterol is not required for growth. The species are found on animals, and some plants and insects. The optimum growth temperature is 30 to 37 degrees Celsius.
Entomoplasmatales is a small order of mollicute bacteria.
Anaeroplasmatales is an order of mollicute bacteria which are generally found in the rumens of cattle and sheep. The only family in the order is the family Anaeroplasmataceae.
In taxonomy, Thermoproteus is a genus of the Thermoproteaceae. These prokaryotes are thermophilic sulphur-dependent organisms related to the genera Sulfolobus, Pyrodictium and Desulfurococcus. They are hydrogen-sulphur autotrophs and can grow at temperatures of up to 95 °C.
Methanococcus is a genus of coccoid methanogens of the family Methanococcaceae. They are all mesophiles, except the thermophilic M. thermolithotrophicus and the hyperthermophilic M. jannaschii. The latter was discovered at the base of a “white smoker” chimney at 21°N on the East Pacific Rise and it was the first archaeal genome to be completely sequenced, revealing many novel and eukaryote-like elements.
In taxonomy, the Methanobacteriales are an order of the Methanobacteria. Species within this order differ from other methanogens in that they can use fewer catabolic substrates and have distinct morphological characteristics, lipid compositions, and RNA sequences. Their cell walls are composed of pseudomurein. Most species are Gram-positive with rod-shaped bodies and some can form long filaments. Most of them use formate to reduce carbon dioxide, but those of the genus Methanosphaera use hydrogen to reduce methanol to methane.
In taxonomy, the Methanococcales are an order of the Methanococci.
In the taxonomy of microorganisms, the Methanomicrobiales are an order of the Methanomicrobia. Methanomicrobiales are strictly carbon dioxide reducing methanogens, using hydrogen or formate as the reducing agent. As seen from the phylogenetic tree based on 'The All-Species Living Tree' Project the family Methanomicrobiaceae is highly polyphyletic within the Methanomicrobiales.
In taxonomy, the Methanobacteriaceae are a family of the Methanobacteriales.
In taxonomy, the Methanocaldococcaceae are a family of microbes within the order Methanococcales. It contains two genera, the type genus Methanocaldococcus and Methanotorris. These species are coccoid in form, neutrophilic to slightly acidophilic, and predominantly motile, and they have a very short generation period, from 25 to 45 minutes under optimal conditions. They produce energy exclusively through the reduction of carbon dioxide with hydrogen. Some species have been found in marine hydrothermal vents.
Methanomicrobiaceae are a family of archaea in the order the Methanomicrobiales.
In taxonomy, the Thermococcaceae are a family of the Thermococcales. Almost all species within the three genera of Thermococcaceae were isolated from hydrothermal vents in the ocean. All are strictly anaerobes.
In taxonomy, Methanobacterium is a genus of the Methanobacteriaceae family of Archaea. Despite the name, this genus belongs not to the bacterial domain but the archaeal domain. Methanobacterium are nonmotile and live without oxygen. Some members of this genus can use formate to reduce methane; others live exclusively through the reduction of carbon dioxide with hydrogen. They are ubiquitous in some hot, low-oxygen environments, such as anaerobic digestors, their wastewater, and hot springs.
Plasmaviridae is a family of bacteria-infecting viruses. Acholeplasma species serve as natural hosts. There is one genus in the family, Plasmavirus, which contains one species: Acholeplasma virus L2. All viruses known in this family have been isolated from species in the class Mollicutes.
Mycoplasmatota is a phylum of bacteria that contains the class Mollicutes. The phylum was originally named "Tenericutes". Notable genera include Mycoplasma, Spiroplasma, Ureaplasma, and Candidatus Phytoplasma.
Entomoplasma is a mollicute bacteria genus. Entomoplasma freundtii can be isolated from the green tiger beetle.
Mesoplasma is a genus of bacteria belonging to the class Mollicutes. Mesoplasma is related to the genus Mycoplasma but differ in several respects.
