BacteriaBacteria (bækˈtɪəriə; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere.
Treponema pallidumTreponema pallidum, formerly known as Spirochaeta pallida, is a spirochaete bacterium with various subspecies that cause the diseases syphilis, bejel (also known as endemic syphilis), 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.
ProkaryoteA prokaryote (pɹoʊˈkærioʊt,_-ət) is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word prokaryote comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel'). In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: Bacteria (formerly Eubacteria) and Archaea (formerly Archaebacteria).
Borrelia burgdorferiBorrelia burgdorferi is a bacterial species of the spirochete class in the genus Borrelia, and is one of the causative agents of Lyme disease in humans. Along with a few similar genospecies, some of which also cause Lyme disease, it makes up the species complex of Borrelia burgdorferi sensu lato. The complex currently comprises 20 accepted and 3 proposed genospecies. B. burgdorferi sensu stricto exists in North America and Eurasia and until 2016 was the only known cause of Lyme disease in North America.
Nonvenereal endemic syphilisBejel, 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" (endemic infections caused by spiral-shaped bacteria called treponemes), 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.
YawsYaws is a tropical infection of the skin, bones, and joints caused by the spirochete bacterium Treponema pallidum pertenue. The disease begins with a round, hard swelling of the skin, in diameter. The center may break open and form an ulcer. This initial skin lesion typically heals after 3–6 months. After weeks to years, joints and bones may become painful, fatigue may develop, and new skin lesions may appear. The skin of the palms of the hands and the soles of the feet may become thick and break open.
