''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; 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'' used to be members of the genus ''
Thiobacillus'', 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'' gen. nov., ''Halothiobacillus'' gen. nov. and '' Thermithiobacillus'' gen. nov." Int. J. Syst. Evol. Microbiol. (2000) 50:489-500.] A further two former ''
Thiobacillus'' 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 ''
Halothiobacillus neapolitanus'' and so were reclassified to the newly designated genus ''
Guyparkeria'' in 2017, as ''
Guyparkeria halophila'' and ''
Guyparkeria hydrothermalis''.
Environmental importance
''Halothiobacillus'' spp. and other
chemolithoautotrophic organisms play an important role in global carbon and sulfur cycles. They are able to depend entirely on inorganic compounds (CO
2 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''
* ''
Halothiobacillus neapolitanus'' (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 me ...
,
Australia by Cecil David 'Guy' Parker in the 1940s - this strain is now a common model organism for autotrophy research, in particular study of
carboxysomes 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 co ...
efficiency during autotrophic growth.
References
External links
Genome page for ''Halothiobacillus neapolitanus c2'' at the Joint Genome Institute
Bacteria genera
Halothiobacillaceae
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