''Halothiobacillus'' is a genus in the ''

Gammaproteobacteria Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota (synonym Proteobacteria). It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically imp ...

''. Both species are obligate aerobic bacteria; they require oxygen to grow. They are also

halotolerant Halotolerance is the adaptation of living organisms to conditions of high salinity. Halotolerant species tend to live in areas such as hypersaline lakes, coastal dunes, saline deserts, salt marshes, and inland salt seas and springs. Halophiles are ...

; they live in environments with high concentrations of salt or other solutes, but don't require them in order to grow. The type species of this genus, ''

Halothiobacillus neapolitanus ''Halothiobacillus'' is a genus in the '' Gammaproteobacteria''. Both species are obligate aerobic bacteria; they require oxygen to grow. They are also halotolerant; they live in environments with high concentrations of salt or other solutes, b ...

'' used to be members of the genus ''

Thiobacillus ''Thiobacillus'' is a genus of Gram-negative Betaproteobacteria. ''Thiobacillus thioparus'' is the type species of the genus, and the type strain thereof is the StarkeyT strain, isolated by Robert Starkey in the 1930s from a field at Rutgers Un ...

'', before they were reclassified in 2000.Kelly, D.P., and Wood, A.P. "Reclassification of some species of ''Thiobacillus'' to the newly designated genera ''

Acidithiobacillus ''Acidithiobacillus'' is a genus of the ''Acidithiobacillia'' in the " Pseudomonadota". The genus includes acidophilic organisms capable of iron and/or sulfur oxidation. Like all ''"Pseudomonadota"'', ''Acidithiobacillus'' spp. are Gram-negative ...

'' gen. nov., ''Halothiobacillus'' gen. nov. and ''

Thermithiobacillus ''Thermithiobacillus'' is a genus of nonsporeforming, rod-shaped, Gram-negative bacteria. The name derives from the Latin ''thermae'', for warm baths, and the Classical Greek θείος, ''theios'' for sulfur. The type species of this genus was ...

'' gen. nov." Int. J. Syst. Evol. Microbiol. (2000) 50:489-500. A further two former ''

'' spp. were also reclassified as '' Halothiobacillus halophilus'' and '' Halothiobacillus hydrothermalis'', both of which were obligate

halophile The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, ...

s rather than being halotolerant and showed comparatively low 16S rRNA gene identity to ''

'' and so were reclassified to the newly designated genus ''

Guyparkeria ''Guyparkeria'' is a genus in the '' Gammaproteobacteria''. Both species are obligate aerobic bacteria; they require oxygen to grow. They are also halophilic and have varying degrees of thermophilicity. They live in environments with high conce ...

'' in 2017, as ''

Guyparkeria halophila ''Guyparkeria'' is a genus in the '' Gammaproteobacteria''. Both species are obligate aerobic bacteria; they require oxygen to grow. They are also halophilic and have varying degrees of thermophilicity. They live in environments with high conce ...

'' and ''

Guyparkeria hydrothermalis ''Guyparkeria'' is a genus in the '' Gammaproteobacteria''. Both species are obligate aerobic bacteria; they require oxygen to grow. They are also halophilic and have varying degrees of thermophilicity. They live in environments with high conce ...

''.

Environmental importance

''Halothiobacillus'' spp. and other

chemolithoautotrophic A lithoautotroph is an organism which derives energy from reactions of reduced compounds of mineral (inorganic) origin. Two types of lithoautotrophs are distinguished by their energy source; photolithoautotrophs derive their energy from light while ...

organisms play an important role in global carbon and sulfur cycles. They are able to depend entirely on inorganic compounds (CO₂ and reduced sulfur) for their carbon and energy needs, but can assimilate some

Krebs cycle The citric acid cycle (CAC)—also known as the Krebs cycle or the TCA cycle (tricarboxylic acid cycle)—is a series of chemical reactions to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and protein ...

intermediates during

autotrophic An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Works", ...

growth.

Species

* '' Halothiobacillus kellyi'' * ''

'' (basonym: ''Thiobacillus neapolitanus''), the type strain of which is ParkerX^T, isolated from decomposing concrete in the sewer outfall of

Melbourne Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

by Cecil David 'Guy' Parker in the 1940s - this strain is now a common model organism for autotrophy research, in particular study of

carboxysome Carboxysomes are bacterial microcompartments (BMCs) consisting of polyhedral protein shells filled with the enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO)—the predominant enzyme in carbon fixation and the rate limiting e ...

s and their role in carbon concentration and maintaining

RuBisCO Ribulose-1,5-bisphosphate carboxylase-oxygenase, commonly known by the abbreviations RuBisCo, rubisco, RuBPCase, or RuBPco, is an enzyme () involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is con ...

efficiency during autotrophic growth.

References

External links

Genome page for ''Halothiobacillus neapolitanus c2'' at the Joint Genome Institute
Bacteria genera Halothiobacillaceae {{Chromatiales-stub