Thermoplasma acidophilum DSM 1728

A thermoacidophilic archaeon, Thermoplasma is a fascinating microorganism whose study can give new insight into how extremophiles can live in such conditions missing some of the generic cell structure that other thermophilic's have. Protease and chaperone assemblies from Thermoplasma have helped illuminate the structure and function of their more complex eukaryotic homologues.The T. acidophilum genome consists of a single circular chromosome of 1,564,906 bp. No plasmids were detected through biochemical methods or DNA sequencing, but a 15.2kbp has previously been reported in other isolates. The genome for T. volcanium is composed of 1,584,804 bp. There has been apparent lateral gene transfer between T. acidophilum and Sulfolobus solfataricus mainly including protein degradation pathways and various transport proteins. These two microorganisms are phylogenetically distant with S. sulfolobus being a crenarchaeon, but they do share the same living environment. While Thermoplasma may share around 252 open reading frames (17%) with Sulfolobus, but surprisingly, no homologues of the genes that mediate sulphur respiration in Archaeoglobus (a fellow archaeon) were found. Instead, homologues of genes that mediate dissimilatory sulphur reduction in Salmonella typhimurium were present. Thermoplasma also contain proteins not present in other archaeal genome including Hta, an archaeal DNA-binding protein that is closely related to bacterial proteins and appear to substitute functionally for the missing histones.Thermoplasma live in extreme environments without a protective outer layer (S-layer, cell wall) and survive with only a plasma membrane. Not to mention they retain a near neutral cytoplasm. They have flagella and are motile, although it is unclear what structure can function as the stator for flagellar rotation. Thermoplasma can metabolize like Sulfolobus through glucose degradation which eventually leads to the TCA cycle. Thermoplasma contain several respiratory chain proteins such as electron transfer flavoproteins and cytochrome b homologues. They are also able to gain energy anaerobically, however, by sulfur respiration.Environments that have characteristics including a pH level between 0.5 - 4.0 with temperatures ranging from 55-60oC are where you can find Thermophiles. Optimum growth conditions are about pH 2 and 60oC. Strands have been isolated from self-heating coal refuse piles and solfatara fields. (From http://microbewiki.kenyon.edu/index.php/Thermoplasma) (MicrobeWiki: Thermoplasma)