Acholeplasmataceae is a family of bacteria. It is the only family in the orderAcholeplasmatales, placed in the class Mollicutes. The family comprises the genera Acholeplasma and Phytoplasma. Phytoplasma has the candidatus status, because members still could not be cultured.
Etymology: The names Acholeplasmataceae and Acholetoplasmatales are derived from the Greek a = not, cholè = bile and plasma = anything moulded or formed.[1] Species in the order Acholeplasmatales can grow in a medium without cholesterol, unlike species in the order Mycoplasmatales. Cholesterol, a sterol, is an important component of the cell membrane of mycoplasmas, whereas in acholeplasmas and in bacteria in general it is absent.
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.
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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.
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In 1987, the division in sterol requiring and not requiring changed with the addition of a third order, Anaeroplasmatales, taking into account that dependence on anaerobic growth conditions is an important characteristic.
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