Acholeplasma
Encyclopedia
Acholeplasma are wall-less bacteria in the Mollicutes
Mollicutes
The Mollicutes are a class of bacteria distinguished by the absence of a cell wall. The word "Mollicutes" is derived from the Latin mollis , and cutis . They are parasites of various animals and plants, living on or in the host's cells. Individuals are very small, typically only 0.2–0.3 μm in size...

 class. They include saprotrophic or pathogenic species. There are 15 recognised species. The G+C
GC-content
In molecular biology and genetics, GC-content is the percentage of nitrogenous bases on a DNA molecule that are either guanine or cytosine . This may refer to a specific fragment of DNA or RNA, or that of the whole genome...

 content is low, ranging from 26 - 36% (mol
Mole (unit)
The mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as an amount of a substance that contains as many elementary entities as there are atoms in 12 grams of pure carbon-12 , the isotope of carbon with atomic weight 12. This corresponds to a value...

%). The genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

s of Acholeplasma species range in size from 1.5 to 1.65 Mbp. Cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 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.

Acholeplasma laidlawii may contaminate bovine serum and also occurs in serum-free cell culture media products. Unsubstantiated evidence of A. laidlawii contamination of tryptone
Tryptone
Tryptone is the assortment of peptides formed by the digestion of casein by the protease trypsin.Tryptone is commonly used in microbiology to produce Lysogeny broth for the growth of E. coli and other microorganisms...

 soya broth existed for some years prior to proof of the organism's contaminating nutrient broth powders. The presence of A. laidlawii in broth powders is a serious problem in routine biopharmaceutical operations where filtration is used as a sterilisation procedure. A. laidlawii may flourish and survive for prolonged periods at refrigeration and ambient temperatures in serum-free cell culture media.
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