Acholeplasmataceae is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

. It is the only family in the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Acholeplasmatales, placed in the class

Mollicutes Mollicutes is a class of bacteria distinguished by the absence of a cell wall and its peptidoglycan. The word "Mollicutes" is derived from the Latin ' (meaning "soft" or "pliable"), and ' (meaning "skin"). Individuals are very small, typically on ...

. The family comprises the genera ''

Acholeplasma ''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 ...

'' and ''

Phytoplasma 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-li ...

''. ''Phytoplasma'' has the

candidatus In prokaryote nomenclature, ''Candidatus'' (abbreviated ''Ca.''; Latin for "candidate of Roman office") is used to name prokaryotic taxa that are well characterized but yet- uncultured. Contemporary sequencing approaches, such as 16S ribosomal R ...

status, because members still could not be cultured.

Etymology Etymology ( ) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. ...

: The names Acholeplasmataceae and Acholetoplasmatales are derived from the Greek ''a'' = not, ''cholè'' = bile and ''plasma'' = anything moulded or formed.D.G. Edward, E.A. Freund
''Amended nomenclature for strains related to Mycoplasma laidlawii.''
J Gen Microbiol. 1970 Jul; 62
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Species in the order Acholeplasmatales can grow in a medium without cholesterol, unlike species in the order

Mycoplasmatales Mycoplasmatales is an order of bacteria in the class Mollicutes. The order consists of the families Spiroplasmataceae and Mycoplasmataceae. As currently (2025) defined by LPSN, this class is synonymous to Entomoplasmatales, a class originally in ...

Cholesterol Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all anima ...

, a

sterol A sterol is any organic compound with a Skeletal formula, skeleton closely related to Cholestanol, cholestan-3-ol. The simplest sterol is gonan-3-ol, which has a formula of , and is derived from that of gonane by replacement of a hydrogen atom on ...

, is an important component of the

cell membrane The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extr ...

of mycoplasmas, whereas in acholeplasmas and in bacteria in general it is absent.

Characteristics

Members of Acholeplasmatales are

facultative anaerobic A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are ''Staphylococcus' ...

. They are

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

s or

commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit f ...

s of vertebrates, insects, or plants; some are saprophytes.

s colonize the phloem sieve elements of

vascular plant Vascular plants (), also called tracheophytes (, ) or collectively tracheophyta (; ), are plants that have lignin, lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified Ti ...

s, causing diseases. They are transmitted by sap-sucking insects (primarily

leafhoppers Leafhopper is the common name for any species from the family Cicadellidae: based on the type genus ''Cicadella''. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind ...

planthoppers A planthopper is any insect in the infraorder Fulgoromorpha, in the suborder Auchenorrhyncha, a group exceeding 12,500 described species worldwide. The name comes from their remarkable resemblance to leaves and other plants of their environment ...

, and

psyllids Psyllidae, the jumping plant lice or psyllids, are a Family (biology), family of small plant-feeding insects that tend to be very host-specific, i.e. each plant-louse species only feeds on one plant species (monophagous) or feeds on a few closel ...

), living in the gut, haemolymph, salivary gland and other organs. Like other mollicutes, they show a high

host specificity In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include ...

Classification

In the first taxonomy of Mollicutes, the classification was based on requiring or not requiring cholesterol for growth. The old order Mycoplasmatales consisted of two families:

Mycoplasmataceae Mycoplasmataceae is a family of bacteria in the order Mycoplasmatales. This family consists of ''Mycoplasma'' and four more genera. In 1967, the order Mycoplasmatales was incorporated into the class Mollicutes. Sexually-transmitted species ...

, which requires cholesterol, and the sterol-nonrequiring Acholeplasmataceae. In view of the many properties in which the acholeplasmas distinguish from species in Mycoplasmataceae and Spiroplasmataceae, Freundt et al. proposed in 1984 to elevate the family Acholeplasmataceae to the ordinal rank Acholeplasmatales, thus separating it from Mycoplasmatales. In 1987, the division in sterol requiring and not requiring changed with the addition of a third order,

Anaeroplasmatales 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. Description Members of the order Anaeroplasmatales can appear as dif ...

, taking into account that dependence on anaerobic growth conditions is an important characteristic. The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclatu ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...

(NCBI)

References

{{Taxonbar, from1=Q390198, from2=Q4670447 Mollicutes

Characteristics

Classification

See also

References