Monday, May 28, 2018

Firmicutes

Firmicutes

From Wikipedia, the free encyclopedia
Firmicutes
Bacillus subtilis Gram.jpg
Bacillus subtilis, Gram stained
Scientific classificatione
Domain:Bacteria
(unranked):Terrabacteria
Phylum:Firmicutes
Gibbons and Murray 1978,[1] Murray, 1984[2]
Classes
The Firmicutes (Latin: firmus, strong, and cutis, skin, referring to the cell wall) are a phylum of bacteria, most of which have Gram-positive cell wall structure.[3] A few, however, such as Megasphaera, Pectinatus, Selenomonas and Zymophilus, have a porous pseudo-outer membrane that causes them to stain Gram-negative. Scientists once classified the Firmicutes to include all Gram-positive bacteria, but have recently defined them to be of a core group of related forms called the low-G+C group, in contrast to the Actinobacteria. They have round cells, called cocci (singular coccus), or rod-like forms (bacillus).
Many Firmicutes produce endospores, which are resistant to desiccation and can survive extreme conditions. They are found in various environments, and the group includes some notable pathogens. Those in one family, the heliobacteria, produce energy through photosynthesis. Firmicutes play an important role in beer, wine, and cider spoilage.

Classes[edit]

The group is typically divided into the Clostridia, which are anaerobic, the Bacilli, which are obligate or facultative aerobes, and the Mollicutes, which are parasites.
On phylogenetic trees, the first two groups show up as paraphyletic or polyphyletic, as do their main genera, Clostridium and Bacillus.[4]

Phylogeny[edit]

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) [5] and National Center for Biotechnology Information (NCBI)[6] and the phylogeny is based on 16S rRNA-based LTP release 111 by The All-Species Living Tree Project [7]


?Synergistaceae {Clostridiales Family XV Incertae Sedis}

Firmicutes s. s.

?Clostridium thermoamylolyticum ♠ Katkocin et al. 1985













































Notes:
♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature LPSN

Genera[edit]

More than 274 genera were considered as of 2016 to be within the Firmicutes phylum, notable genera of Firmicutes include:
Bacilli, order Bacillales
Bacilli, order Lactobacillales

Health implications[edit]

Firmicutes make up the largest portion of the mouse and human gut microbiome.[8] The division Firmicutes as part of the gut flora has been shown to be involved in energy resorption, and potentially related to the development of diabetes and obesity.[9][10][11][12]
Firmicutes spp. are part of a normal, healthy placental microbiome.[13][14]
See also: Infectobesity
Presence of Christensenella (Firmicutes, in class Clostridia), isolated from human faeces, has been found to correlate with lower body mass index.[15]

Laboratory detection[edit]

The presence of Firmicutes can be reliably detected with polymerase chain reaction (PCR) techniques.[16]

References[edit]

  1. Jump up^ Gibbons, N. E. & Murray, R. G. E. 1978. Proposals concerning the higher taxa of bacteria. Int J Syst Bacteriol 28:1–6, (PDF)
  2. Jump up^ Murray, R.G.E. (1984). The higher taxa, or, a place for everything...?. In: N.R. Krieg & J.G. Holt (ed.) Bergey's Manual of Systematic Bacteriology, vol. 1, The Williams & Wilkins Co., Baltimore, p. 31-34.
  3. Jump up^ "Firmicutes" at Dorland's Medical Dictionary
  4. Jump up^ Wolf M, Müller T, Dandekar T, Pollack JD (May 2004). "Phylogeny of Firmicutes with special reference to Mycoplasma (Mollicutes) as inferred from phosphoglycerate kinase amino acid sequence data". Int. J. Syst. Evol. Microbiol. (Comparative Study). 54 (Pt 3): 871–5. doi:10.1099/ijs.0.02868-0. PMID 15143038.
  5. Jump up^ J.P. Euzéby. "Firmicutes". List of Prokaryotic names with Standing in Nomenclature (LPSN). Archived from the originalon January 27, 2013. Retrieved 2013-03-20.
  6. Jump up^ Sayers; et al. "Firmicutes". National Center for Biotechnology Information (NCBI) taxonomy database. Retrieved 2013-03-20.
  7. Jump up^ All-Species Living Tree Project."16S rRNA-based LTP release 111 (full tree)" (PDF). Silva Comprehensive Ribosomal RNA Database. Retrieved 2013-03-20.
  8. Jump up^ Ley RE, Peterson DA, Gordon JI (2006). "Ecological and evolutionary forces shaping microbial diversity in the human intestine". Cell (Review). 124 (4): 837–48. doi:10.1016/j.cell.2006.02.017. PMID 16497592.
  9. Jump up^ Ley RE, Turnbaugh PJ, Klein S, Gordon JI (2006). "Microbial ecology: human gut microbes associated with obesity". Nature(Clinical Trial). 444 (7122): 1022–3. doi:10.1038/4441022a. PMID 17183309.
  10. Jump up^ Henig, Robin Marantz (2006-08-13). "Fat Factors". New York Times Magazine. Retrieved 2008-09-28.
  11. Jump up^ Ley RE, Bäckhed F, Turnbaugh P, Lozupone CA, Knight RD, Gordon JI (August 2005). "Obesity alters gut microbial ecology". Proc. Natl. Acad. Sci. U.S.A. (Research Support). 102 (31): 11070–5. doi:10.1073/pnas.0504978102. PMC 1176910 Freely accessible. PMID 16033867. Retrieved 2008-09-28.
  12. Jump up^ Komaroff AL. The Microbiome and Risk for Obesity and Diabetes. JAMA. Published online December 22, 2016. doi:10.1001/jama.2016.20099
  13. Jump up^ Mor, Gil; Kwon, Ja-Young (2015). "Trophoblast-microbiome interaction: a new paradigm on immune regulation". American Journal of Obstetrics and Gynecology. 213 (4): S131–S137. doi:10.1016/j.ajog.2015.06.039. ISSN 0002-9378. PMID 26428492.
  14. Jump up^ Todar, K. "Pathogenic E. coli". Online Textbook of Bacteriology. University of Wisconsin–Madison Department of Bacteriology. Retrieved 2007-11-30.
  15. Jump up^ Goodrich, Julia K.; Waters, Jillian L.; Poole, Angela C.; Sutter, Jessica L.; Koren, Omry; Blekhman, Ran; Beaumont, Michelle; Van Treuren, William; Knight, Rob; Bell, Jordana T.; Spector, Timothy D.; Clark, Andrew G.; Ley, Ruth E. (2014). "Human Genetics Shape the Gut Microbiome". Cell. 159 (4): 789–799. doi:10.1016/j.cell.2014.09.053. ISSN 0092-8674.open access publication – free to read
  16. Jump up^ Haakensen M, Dobson CM, Deneer H, Ziola B (July 2008). "Real-time PCR detection of bacteria belonging to the Firmicutes Phylum". Int. J. Food Microbiol. (Research Support). 125 (3): 236–41. doi:10.1016/j.ijfoodmicro.2008.04.002. PMID 18501458. Retrieved 2008-09-28.
Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)