Thermocrinis jamiesonii sp. nov., a thiosulfate-oxidizing, autotropic thermophile isolated from a geothermal spring.

An obligately thermophilic, chemolithotrophic, microaerophilic bacterium, designated strain GBS1T, was isolated from the water column of Great Boiling Spring, Nevada, USA. Thiosulfate was required for growth. Although capable of autotrophy, growth of GBS1T was enhanced in the presence of acetate, peptone or Casamino acids. Growth occurred at 70-85 °C with an optimum at 80 °C, at pH 6.50-7.75 with an optimum at pH 7.25, with 0.5-8 % oxygen with an optimum at 1-2 % and with ≤ 200 mM NaCl. The doubling time under optimal growth conditions was 1.3 h, with a final mean cell density of 6.2 ± 0.5 × 107 cells ml- 1. Non-motile, rod-shaped cells 1.4-2.4 × 0.4-0.6 µm in size occurred singly or in pairs. The major cellular fatty acids (>5 % of the total) were C20 : 1ω9c, C18 : 0, C16 : 0 and C20 : 0. Phylogenetic analysis of the GBS1T 16S rRNA gene sequence indicated an affiliation with Thermocrinis ruber and other species of the genus Thermocrinis, but determination of 16S rRNA gene sequence similarity ( ≤ 97.10 %) and in silico estimated DNA-DNA hybridization values ( ≤ 18.4 %) with the type strains of recognized Thermocrinis species indicate that the novel strain is distinct from described species. Based on phenotypic, genotypic and phylogenetic characteristics, a novel species, Thermocrinis jamiesonii sp. nov., is proposed, with GBS1T ( = JCM 19133T = DSM 27162T) as the type strain.

High-Quality Draft Genome Sequence of Thermocrinis jamiesonii GBS1T Isolated from Great Boiling Spring, Nevada.

The draft genome of Thermocrinis jamiesonii GBS1T is 1,315,625 bp in 10 contigs and encodes 1,463 predicted genes. The presence of sox genes and various glycoside hydrolases and the absence of uptake NiFe hydrogenases (hyaB) are consistent with a requirement for thiosulfate and suggest the ability to use carbohydrate polymers.

Isolation of diverse members of the Aquificales from geothermal springs in Tengchong, China.

The order Aquificales (phylum Aquificae) consists of thermophilic and hyperthermophilic bacteria that are prominent in many geothermal systems, including those in Tengchong, Yunnan Province, China. However, Aquificales have not previously been isolated from Tengchong. We isolated five strains of Aquificales from diverse springs (temperature 45.2-83.3°C and pH 2.6-9.1) in the Rehai Geothermal Field from sites in which Aquificales were abundant. Phylogenetic analysis showed that four of the strains belong to the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, including strains distant enough to likely justify new species of Hydrogenobacter and Hydrogenobaculum. The additional strain may represent a new genus in the Hydrogenothermaceae. All strains were capable of aerobic respiration under microaerophilic conditions; however, they had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction.