The genus ''Annwoodia'' was named in 2017 to circumscribe an organism previously described as a member 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 ...

'', ''Thiobacillus aquaesulis'' - the type and only species is ''Annwoodia aquaesulis'', which was isolated from the geothermal waters of the

Roman Baths In ancient Rome, (from Greek , "hot") and (from Greek ) were facilities for bathing. usually refers to the large imperial bath complexes, while were smaller-scale facilities, public or private, that existed in great numbers throughout ...

in the city of Bath in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

by Ann P. Wood and Donovan P. Kelly of the

University of Warwick The University of Warwick ( ; abbreviated as ''Warw.'' in post-nominal letters) is a public research university on the outskirts of Coventry between the West Midlands (county), West Midlands and Warwickshire, England. The university was founded i ...

- the genus was subsequently named to honour Wood's contribution to microbiology. The genus falls within the family '' Thiobacillaceae'' along with ''

'' and '' Sulfuritortus'', both of which comprise

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", ...

organisms dependent on

thiosulfate Thiosulfate ( IUPAC-recommended spelling; sometimes thiosulphate in British English) is an oxyanion of sulfur with the chemical formula . Thiosulfate also refers to the compounds containing this anion, which are the salts of thiosulfuric acid, ...

, other

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

oxyanions and

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds lar ...

as electron donors for chemolithoheterotrophic growth. Whilst ''Annwoodia'' spp. and '' Sulfuritortus'' spp. are

thermophilic A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...

, ''

'' spp. are

mesophilic A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from . The optimum growth temperature for these organisms is 37°C. The term is mainly applied to microorganisms. Organi ...

. ''A. aquaesulis'' is moderately

with an optimum temperature of 43 °C and a temperature range of 30 °C to 55 °C - a similar temperature profile to the related genus '' Sulfuritortus'' - and is a facultative

chemolithoautotroph 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 ...

that grows on reduced

oxyanions such as

as the

electron donor In chemistry, an electron donor is a chemical entity that donates electrons to another compound. It is a reducing agent that, by virtue of its donating electrons, is itself oxidized in the process. Typical reducing agents undergo permanent chem ...

and

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

bicarbonate In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochemic ...

as the carbon source. Unlike ''

'' spp., ''Annwoodia'' spp. do not produce

tetrathionate The tetrathionate anion, , is a sulfur oxoanion derived from the compound tetrathionic acid, H2S4O6. Two of the sulfur atoms present in the ion are in oxidation state 0 and two are in oxidation state +5. Alternatively, the compound can be viewed ...

during growth on

and can also grow heterotrophically on nutrient broth. Elementary

is deposited by the organism in batch culture with

as the electron donor, but not in

chemostat A chemostat (from ''chem''ical environment is ''stat''ic) is a bioreactor to which fresh medium is continuously added, while culture liquid containing left over nutrients, metabolic end products and microorganisms is continuously removed at the sa ...

culture. ''A. aquaesulis'' can use

nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...

as a

terminal electron acceptor An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. It is an oxidizing agent that, by virtue of its accepting electrons, is itself reduced in the process. Electron acceptors are sometimes mista ...

, as well as molecular

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

. The dominant respiratory quinone is ubiquinone-8 and the G+C fraction of the type strain of the type species is 67.5 mol%. All members of the genus produce volutin (

polyphosphate Polyphosphates are salts or esters of polymeric oxyanions formed from tetrahedral PO4 (phosphate) structural units linked together by sharing oxygen atoms. Polyphosphates can adopt linear or a cyclic ring structures. In biology, the polyphosphate e ...

) granules but not capsules or

endospores An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. The name "endospore" is suggestive of a spore or seed-like form (''endo'' means 'within'), but it is not a true spore (i.e., no ...

. ''A. aquaesulis'' has a pH optimum of 7.5-8.0 and pH range of 7.0 to 9.0. Whilst nutrient broth and

yeast extract Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations, a ...

will support heterotrophic growth, simple carbon compounds and ions such as sugars, organic acids,

formate Formate (IUPAC name: methanoate) is the conjugate base of formic acid. Formate is an anion () or its derivatives such as ester of formic acid. The salts and esters are generally colorless.Werner Reutemann and Heinz Kieczka "Formic Acid" in ''Ull ...

and monomethylamine do not support growth.

Ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary a ...

is the only source of nitrogen. '' Annwoodia aquaesulis'' strains have been detected in mixed-population packed-bed reactors containing

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

as a source of carbon, elementary

as the electron donor and

as the terminal electron acceptor, as well as in karstic sulfidic thermal

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...

ecosystems of broad similarity to those from which the type strain was isolated '' Annwoodia aquaesulis'' grown on

trithionate Trithionate is an oxyanion of sulfur with the chemical formula . It is the conjugate base of trithionic acid. Dilute sodium hydroxide hydrolyzes as follows, yielding sodium thiosulfate and sodium trithionate: 2 + 6 NaOH + 9 → + 2 + 8 Ce ...

has high growth yields, which are broadly similar to those of ''

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 ...

'' spp., and are higher than members of the closely related genus ''

'', indicating core metabolic differences. This high yield was observed in spite of 70% more

being fixed than could be accounted for as

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

, indicating the excretion of a carbon intermediate, which is not observed in ''

Thermithiobacillus tepidarius ''Thermithiobacillus tepidarius'' (from the Latin ''tepidarium''; a warm bath fed by natural thermal water) is a member of the ''Acidithiobacillia'' isolated from the thermal groundwaters of the Roman Baths (Bath), Roman Baths at Bath, Somerset, ...

'', which was isolated from the same location at the

in Bath, also by enrichment culture on

as the sole electron donor and molecular

as the terminal electron acceptor.

References

{{Taxonbar, from=Q48999579 Nitrosomonadales Monotypic bacteria genera Bacteria genera