![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/2/29/Treponema_pallidum.jpg/640px-Treponema_pallidum.jpg&w=640&q=50)
Spirochaete
Phylum of bacteria / From Wikipedia, the free encyclopedia
A spirochaete (/ˈspaɪroʊˌkiːt/)[4] or spirochete is a member of the phylum Spirochaetota (also called Spirochaetes[5] /ˌspaɪroʊˈkiːtiːz/), which contains distinctive diderm (double-membrane) Gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or spiraled, hence the name) cells.[6] Spirochaetes are chemoheterotrophic in nature, with lengths between 3 and 500 μm and diameters around 0.09 to at least 3 μm.[7]
Spirochaetes | |
---|---|
![]() | |
Treponema pallidum, a spirochaete which causes syphilis | |
Scientific classification ![]() | |
Domain: | Bacteria |
Phylum: | Spirochaetota Garrity and Holt 2021[1] |
Class: | Spirochaetia Paster 2020[2]: 471–563 [3] |
Orders | |
| |
Synonyms | |
|
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Spirochete_Cross_Section.png/640px-Spirochete_Cross_Section.png)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Endoflagella_Components.pdf/page1-640px-Endoflagella_Components.pdf.jpg)
Fig. 2: A side-view of a spirochete cell which shows two axial filaments in opposing motion. One axial filament rotates in a clockwise orientation; an adjacent axial filament rotates in a counter-clockwise orientation. Rotation of the endoflagella creates torsion and drives the corkscrew rotation of the cell.
Fig. 3: An expanded view of the cellular membranes that surround endoflagellum. Both the inner and outer membrane contain a phospholipid bi-layer, with non-polar fatty acid chains in-ward of polar phosphorus heads. Peptidoglycan, the cell wall, provides structure in bacterial microorganisms. Axial filaments are superior to the peptidoglycan.
Spirochaetes are distinguished from other bacterial phyla by the location of their flagella, called endoflagella, or periplasmic flagella, which are sometimes called axial filaments.[8][9] Endoflagella are anchored at each end (pole) of the bacterium within the periplasmic space (between the inner and outer membranes) where they project backwards to extend the length of the cell.[10] These cause a twisting motion which allows the spirochaete to move. When reproducing, a spirochaete will undergo asexual transverse binary fission. Most spirochaetes are free-living and anaerobic, but there are numerous exceptions. Spirochaete bacteria are diverse in their pathogenic capacity and the ecological niches that they inhabit, as well as molecular characteristics including guanine-cytosine content and genome size.[11][12]