Thermocrinis Jamiesonii

''Thermocrinis jamiesonii'' is a Gram-negative bacterium that is thermophilic, growing at temperatures ranging from 70 to 85°C. It grows as a chemolithoautotroph or chemolithoheterotroph, using thiosulfate as its sole electron donor, and is obligately microaerophilic. The strain GBS1^T was isolated from Great Boiling Spring, Nevada, USA.

Physiology

''Thermocrinis jamiesonii'' is a chemoautotrophic and chemolithoheterotrophic bacterium from the family Aquificaceae. It requires thiosulfate as an electron donor. It cannot use sulfur or hydrogen like others within this genus. This species can tolerate a higher NaCl concentration (1.17%) than other species within the genus, which includes ''Thermocrinis albus'' (0.7%), ''Thermocrinis minervae'' (0.5%), and ''Thermocrinis ruber'' (0.5%). ''T. jamiesonii'' is an obligate microaerophile, with a growth range of 0.5-8% oxygen, growing optimally at 1-2%, and cannot grow anaerobically. A neutral pH is preferred, ranging between 6.50 and 7.75, with optimal growth at 7.25. ''Thermocrinis jamiesonii'' can use peptone, Casamino acids, and acetate as carbon sources for chemolithoheterotrophic growth. It cannot use yeast extract, glucose, formate, or formamide.

Morphology

''Thermocrinis jamiesonii'' is a rod-shaped bacterium that was observed as individual or pairs. The length of cells ranges from 1.4 to 2.4 µm, with width ranging from 0.4 to 0.6 µm. Flagella have not been observed through electron microscopy, and motility has not been observed. However, genes encoding flagella were found in the genome, suggesting that motility may be expressed ''in situ''. Spores did not form.

Phylogeny

A phylogenetic analysis of the 16S rRNA gene sequence showed that ''Thermocrinis jamiesonii'' is most closely related to '' Thermocrinis ruber'', within the family Aquificaceae. Other genera in the family include Aquifex and Hydrogenobacter.

Genomic analysis

The draft genome of ''Thermocrinis jamiesonii'' is 1,315,625 bp long in 10 contigs. It encodes for 1,463 genes, 1,415 of which are protein-coding, 43 tRNA genes, and one rRNA operon. 36 carbohydrate-active enzymes (CAZymes) were found, including glycoside hydrolases (GHs), which suggests that ''T. jamiesonii'' may be able to grow on polymers, such as starch, like ''Thermocrinis minervae''. A ''sox'' gene cluster (''soxABXYZ'') was present, which is required for thiosulfate oxidation. It lacks NiFe hydrogenase (''hyaB'') and formate dehydrogenase genes (''fdhA''), indicating that it cannot grow with H₂ or formate, distinguishing it from other ''Thermocrinis'' species. It lacks the 2-oxoglutarate-ferredoxin oxidoreductase gene, which is required for the rTCA cycle to fix CO₂ but does encode for other enzymes present in this cycle. All genes essential to flagellar assembly were present. Genes encoding signature lipids C_20-22 found in the family Aquificaceae were present.

Ecology

''Thermocrinis jamiesonii'' was isolated from the water column on the north side of Great Boiling Spring near Gerlach, Nevada, USA. The abundance of ''Thermocrinis'' species in the spring water was estimated by 16S rRNA gene surveys as 91.5%.

Etymology

''Thermocrinis jamiesonii'' was named after David and Sandy Jamieson who provided logistical support during the sampling process and allowed research access to many scientists to Great Boiling Spring in Nevada, USA.

References

{{Taxonbar, from=Q29566029

External links

Species: Thermocrinis jamiesonii - List of Prokaryotic names with Standing in Nomenclature

Type strain of Thermocrinis jamiesonii at BacDive – the Bacterial Diversity Metadatabase

Aquificota