| color = lightgrey
| name = Mycoplasmas
| regnum = Bacteria
| phylum = Firmicutes
| classis = Mollicutes
| subdivision_ranks = Orders
| subdivision =
The Mollicutes are an unusual group of bacteriadistinguished by the absence of a cell wall; a cell wall is found in most other groups. They are commonly called mycoplasmas, and are primarily parasites of various animals and plants, living within the host's cells. Individuals are very small, typically only 0.2-0.3 μm in size, and vary in form, although most have sterolsthat make the cell membrane somewhat more rigid. Many are able to move about through gliding. The unusual genus Spiroplasma is helical and moves by twisting.
In addition to their simplified structure, Mollicutes have simplified genomes. For instance, Mycoplasma genitalium has a total genome size of 580 000 base pairs, one of the smallest yet sequenced. Although they have been considered as possible candidates for the most primitive bacteria, it now appears they developed from the gram-positive Firmicutes, and they are now classified with them.
A few Mollicutes cause diseases in humans, entering cells in the respiratory or urogenital tracts. These include certain species of Mycoplasma, Ureaplasma, and Erysipelothrix.de:Mollicutes
Categories: Bacteria| Firmicutes| Mollicutes
This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Mollicutes Wikipedia article Mollicutes.