Spirochaete
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 Treponema pallidum spirochetes.
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Spirochaetaceae |
Spirochaetes is a phylum of distinctive Gram-negative bacteria, which have long, helically coiled cells.[1] Spirochetes are chemoheterotrophic in nature, with lengths between 5 and 500 µm and diameters around 0.1-0.6 µm.[citation needed] Spriochetes are distinguished from other bacterial phyla by the presence of flagella running lengthwise between the cell membrane and cell wall, called axial filaments. These cause a twisting motion which allows the spirochaete to move about.
The spirochaetes are divided into three families, all placed within a single order. Important members of this phylum include
- Leptospira species, which causes leptospirosis
- Borrelia burgdorferi, which causes Lyme disease
- Borrelia recurrentis, which causes Relapsing fever[2]
- Treponema pallidum, which causes syphilis
- Leptospiractero haemorrhagiae, which causes Weil's disease [3]
The genome of spirochaetes are also highly unusual and consists of both linear chromosomes and plasmids.[4] Most spirochaetes are free-living and anaerobic, but there are numerous exceptions, including the above.
Cavalier-Smith has postulated that the Spirochaetes belong in a larger clade called Gracilicutes.[5]
[edit] Historical
Salvarsan, the first antibiotic in medical history, was effective against spirochaetes only and was primarily used to cure Syphilis.
It has been suggested by Lynn Margulis that eukaryotic flagella were derived from symbiotic spirochaetes, but few biologists accept this, as there is no close structural similarity between the two.
[edit] References
- ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill. ISBN 0838585299.
- ^ Schwan T (1996). "Ticks and Borrelia: model systems for investigating pathogen-arthropod interactions". Infect Agents Dis 5 (3): 167-81. PMID 8805079.
- ^ McBride A, Athanazio D, Reis M, Ko A (2005). "Leptospirosis". Curr Opin Infect Dis 18 (5): 376-86. PMID 16148523.
- ^ Hinnebusch J, Tilly K (1993). "Linear plasmids and chromosomes in bacteria.". Mol Microbiol 10 (5): 917-22. PMID 7934868.
- ^ Cavalier-Smith, T. (2006). "Rooting the tree of life by transition analyses". Biology Direct 1 (19). Accessed 10 March 2006
