Acholeplasmataceae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

. It is the only family in the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Acholeplasmatales, placed in the class Mollicutes. 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 ran ...

'' and '' Phytoplasma''. ''Phytoplasma'' has the candidatus status, because members still could not be cultured.

Etymology Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...

: 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.

Cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...

, a

sterol Sterol is an organic compound with formula , whose molecule is derived from that of gonane by replacement of a hydrogen atom in position 3 by a hydroxyl group. It is therefore an alcohol of gonane. More generally, any compounds that contain the go ...

, is an important component of the

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

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 '' Staphylococc ...

. They are

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s or commensals of vertebrates, insects, or plants; some are saprophytes. Phytoplasmas colonize the phloem sieve elements of

vascular plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They al ...

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

leafhoppers A leafhopper is the common name for any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and a ...

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 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 closely related plants ( ...

), 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 a ...

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, 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 diff ...

, 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 (LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the United States 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)

References

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

Characteristics

Classification

See also

References