Firmicutes

{{Taxobox | color = lightgrey | name = Firmicutes | regnum = Bacteria | divisio = Firmicutes | subdivision_ranks = Classes | subdivision = Bacilli
Clostridia
Mollicutes }} The Firmicutes are a group of bacteria, most of which have Gram-positivestains. A few, the Mollicutesor mycoplasmas, lack cell wallsaltogether and so do not respond to Gram staining, but still lack the second membrane found in other Gram-negative forms. Originally the Firmicutes were taken to include all Gram-positive bacteria, but more recently they tend to be restricted to a core group of related forms, called the low G+Cgroup in contrast to the Actinobacteria. They have round cells, called cocci (singular coccus), or rod-shaped forms.

Many Firmicutes produce endospores, which are resistant to desiccation and can survive extreme conditions. They are found in various environments, and some notable pathogens. Those in one family, the heliobacteria, produce energy through photosynthesis.

The group is typically divided into the Clostridia, which are anaerobic, the Bacilli, which are obligate or facultative aerobes, and the Mollicutes. On molecular trees the first two groups show up as paraphyleticor polyphyletic, as do their main genera, Clostridium and Bacillus. It is likely these groups will undergo revision.

Notable genera of Firmicutes include:

Bacilli, order Bacillales

• Bacillus
• Listeria
• Staphylococcus

Bacilli, order Lactobacillales

• Enterococcus
• Lactobacillus
• Lactococcus
• Leuconostoc
• Streptococcus

Clostridia

• Acetobacterium
• Clostridium
• Eubacterium
• Heliobacterium
• Heliospirillum
• Sporomusa

Mollicutes

• Mycoplasma
• Spiroplasma
• Ureaplasma
• Erysipelothrixde:Firmicutes

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This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Firmicutes Wikipedia article Firmicutes.