Treponema pallidum, formerly known as Spirochaeta pallida, is a microaerophilic spirochaete bacterium with subspecies that cause the diseases syphilis, bejel, and yaws. It is transmitted only among humans. It is a helically coiled microorganism usually 6–15 μm long and 0.1–0.2 μm wide. T. pallidum's lack of either a tricarboxylic acid cycle or oxidative phosphorylation results in minimal metabolic activity. The treponemes have a cytoplasmic and an outer membrane. Using light microscopy, treponemes are visible only by using dark-field illumination. T. pallidum consists of three subspecies, T. p. pallidum, T. p. endemicum, and T. p. pertenue, each of which has a distinct associated disease.
A spirochaete or spirochete is a member of the phylum Spirochaetota, which contains distinctive diderm (double-membrane) gram-negative bacteria, most of which have long, helically coiled cells. Spirochaetes are chemoheterotrophic in nature, with lengths between 3 and 500 μm and diameters around 0.09 to at least 3 μm.
The Thermoprotei is a class of the Thermoproteota.
Bejel, or endemic syphilis, is a chronic skin and tissue disease caused by infection by the endemicum subspecies of the spirochete Treponema pallidum. Bejel is one of the "endemic treponematoses", a group that also includes yaws and pinta. Typically, endemic trepanematoses begin with localized lesions on the skin or mucous membranes. Pinta is limited to affecting the skin, whereas bejel and yaws are considered to be invasive because they can also cause disease in bone and other internal tissues.
Erysipelothrix is a genus of bacteria containing four described species, Erysipelothrix rhusiopathiae, Erysipelothrix tonsillarum, Erysipelothrix inopinata and Erysipelothrix larvae. Additional species have been proposed based on DNA-DNA hybridization studies "The hallmark of Erysipelothrix is the presence of a type B cell wall, in which the peptide bridge is formed between amino acids at positions 2 and 4 of adjacent peptide side-chains and not, as in the vast majority of bacteria, between amino acids at positions 3 and 4."
Fibrobacterota is a small bacterial phylum which includes many of the major rumen bacteria, allowing for the degradation of plant-based cellulose in ruminant animals. Members of this phylum were categorized in other phyla. The genus Fibrobacter was removed from the genus Bacteroides in 1988.
The Erysipelotrichaceae are a family of Gram-positive bacteria.
In taxonomy, the Methanocaldococcaceae are a family of microbes within the order Methanococcales. It contains two genera, the type genus Methanocaldococcus and Methanotorris. These species are coccoid in form, neutrophilic to slightly acidophilic, and predominantly motile, and they have a very short generation period, from 25 to 45 minutes under optimal conditions. They produce energy exclusively through the reduction of carbon dioxide with hydrogen. Some species have been found in marine hydrothermal vents.
In taxonomy, Methanococcoides is a genus of the Methanosarcinaceae.
Haladaptatus is a genus of halophilic archaea in the family of Halobacteriaceae. The members of Haladaptatus thrive in environments with salt concentrations approaching saturation
Halobaculum is a genus of the Halorubraceae.
Halobiforma is a genus of halophilic archaea of the family Natrialbaceae.
Halomicrobium is a genus of the Haloarculaceae.
In taxonomy, Haloplanus is a genus of the Halobacteriaceae.
Natrinema is a genus of the Natrialbaceae.
In taxonomy, Methanocorpusculum is a genus of microbes within the family Methanocorpusculaceae. The species within Methanocorpusculum were first isolated from biodisgester wastewater and activated sludge from anaerobic digestors. In nature, they live in freshwater environments. Unlike most other methanogenic archaea, they do not require high temperatures or extreme salt concentrations to live and grow.
Armatimonadota is a phylum of gram-negative bacteria.
Brachyspira is a genus of bacteria classified within the phylum Spirochaetota.
Brachyspira innocens is a species of bacteria. It is thought to be a commensal bacterium.
The Treponemataceae are a family of spirochete bacteria. The clade includes a number of significant pathogens, such as Treponemapallidum, the cause of human syphilis.
