Thermococcus thioreducens sp. nov., a novel hyperthermophilic, obligately sulfur-reducing archaeon from a deep-sea hydrothermal vent

Abstract

96W). The cells of strain OGL-20PT have an irregular coccoid shape and are motile with a single flagellum. Growth was observed within a pH range of 5.0"8.5 (optimum pH 7.0), an NaCl concentration range of 1-5 % (w/v) (optimum 3 %) and a temperature range of 55-94 6C (optimum 83-85 6C). The novel isolate is strictly anaerobic and obligately dependent upon elemental sulfur as an electron acceptor, but it does not reduce sulfate, sulfite, thiosulfate, Fe(III) or nitrate. Proteolysis products (peptone, bacto-tryptone, Casamino acids and yeast extract) are utilized as substrates during sulfur reduction. Strain OGL-20P T is resistant to ampicillin, chloramphenicol, kanamycin and gentamicin, but sensitive to tetracycline and rifampicin. The G+C content of the DNA is 52.9 mol%. The 16S rRNA gene sequence analysis revealed that strain OGL-20P T is closely related to Thermococcus coalescens and related species, but no significant homology by DNA-DNA hybridization was observed between those species and the new isolate. On the basis of physiological and molecular properties of the new isolate, we conclude that strain OGL-20P T represents a new separate species within the genus Thermococcus, for which we propose the name Thermococcus thioreducens sp. nov. The type strain is OGL-20P

The Temperature Gradient-Forming Device, an Accessory Unit for Normal Light Microscopes To Study the Biology of Hyperthermophilic Microorganisms

“…Swimming speeds at temperatures other than 85°C may be found in unusual physiology (27), while Thermococcus stetteri shows an unusually high maximum growth temperature and has been described as "nonmotile or motile with a polar tuft of flagella" (28). Finally, Thermococcus thioreducens was chosen due to its description as an obligate S 0 reducer (29). All these strains were analyzed for motility after growth at 85°C in the rich MAYTP medium or in the poor SMES medium (T. aegaeus did not grow in MAYTP medium).…”

Contribution of crenarchaeal autotrophic ammonia oxidizers to the dark primary production in Tyrrhenian deep waters (Central Mediterranean Sea)

“…Similarly to other members of Eury-and Crenarchaeota (Jolivet et al, 2003;Simon et al, 2005;Pikuta et al, 2007), the addition of rifampicin (100 mg ml À1 ), an antibiotic agent inactivating prokaryotic DNA-dependent RNA polymerase, completely inhibited CO 2 fixation, whereas there was no toxic effect of radicicol (20 mg ml À1 ), a natural product that inhibits DNA topoisomerase IV of some thermophilic crenarchaea (Gadelle et al, 2005). Depletion of oxygen in the deep seawater samples by addition of sulfide caused a slight decrease in primary production rates compared with untreated control (P ¼ 0.018).…”

Characterization of a Zinc-Containing Alcohol Dehydrogenase with Stereoselectivity from the Hyperthermophilic Archaeon Thermococcus guaymasensis

“…All members of the genus Thermococcus are chemoorganotrophs which can grow on peptide-containing substrates (6,50), and some of them are able to utilize carbohydrates, including starch and chitin as a carbon source (6), though some are capable of producing H 2 from CO (38,61). Glycolysis from glucose to pyruvate in Thermococcus celer and Thermococcus litoralis appears to occur via a modified Embden-Meyerhof (EM) pathway containing ADP-dependent hexose kinase and phosphofructokinase and a tungsten-containing glyceraldehyde-3-phosphate, ferredoxin oxidoreductase (59).…”