Physiology and Metabolism of Thermus

Sharp, Richard; Cossar, D.; Williams, Ruth

doi:10.1007/978-1-4615-1831-0_3

Cited by 6 publications

(4 citation statements)

References 96 publications

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Section: Introductionmentioning

confidence: 99%

“…Although some strains grow mixotrophically (Skirnisdottir et al, 2001), almost all strains of the genus Thermus are obligate heterotrophs that live in various terrestrial hot environments at temperatures higher than about 55˚C and neutral to alkaline pH (Brock & Boylen, 1973;Pask-Hughes & Williams, 1975; Kristjánsson & Alfredsson, 1983;Williams & da Costa, 1992). Under anaerobic conditions, some strains of the genus Thermus are able to grow with NO { 3 , Fe(III) and S 0 as terminal electron acceptors instead of O 2 (Williams & da Costa, 1992;Sharp et al, 1995;Kieft et al, 1999).In deep-sea hydrothermal vent environments, however, most thermophiles had been thought to be strict anaerobes until the recent discovery of facultatively aerobic thermophiles from deep-sea hydrothermal vent chimneys (Blöchl et al, 1997; Reysenbach et al, 2000a). In addition, many strictly aerobic and thermophilic bacterial strains, including Thermus thermophilus Gy1211, have been isolated from deep-sea hydrothermal vent environments in the MidAtlantic Ridge and Guaymas Basin (Marteinsson et al, 1995(Marteinsson et al, , 1999.…”

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confidence: 99%

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Marinithermus hydrothermalis gen. nov., sp. nov., a strictly aerobic, thermophilic bacterium from a deep-sea hydrothermal vent chimney

Sako

Nakagawa

Takai³

et al. 2003

International Journal of Systematic and Evolutionary Microbiology

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A novel thermophilic marine bacterium, designated strain T1 T , was isolated from a deep-sea hydrothermal vent chimney sample collected from the Suiyo Seamount in the Izu-Bonin Arc, Japan, at a depth of 1385 m. Cells of strain T1 T were rod-shaped, occurring in pairs or filamentous, and stained Gram-negative. Growth was observed between 50?0 and 72?5˚C (optimum 67?5˚C; 30 min doubling time) and at pH 6?25-7?75 (optimum pH 7?00). The isolate absolutely required NaCl, at a concentration of 0?5-4?5 % (optimum 3?0 %). It was a strictly aerobic heterotroph capable of growing solely on complex organic substrates such as yeast extract, tryptone and Casamino acids, utilizing glutamate, proline, serine, cellobiose, trehalose, sucrose, acetate and pyruvate as complementary substrates. The G+C content of the genomic DNA was 68?6 mol%. The 16S rRNA gene sequence of the isolate was most similar to those from members of the genus Thermus, but the isolate was distantly related to them at the genus level (,90 %). In addition, phylogenetic analysis indicated that the isolate was on a novel lineage, deeply branched prior to divergence of the genus Thermus. On the basis of phylogenetic analysis and physiological traits of the isolate, it should be described as a member of a novel genus distinct from the previously described genus Thermus. The name Marinithermus gen. nov. is proposed, with Marinithermus hydrothermalis gen. nov., sp. nov. as the type species. The type strain of M. hydrothermalis gen. nov., sp. nov. is strain T1 T (5JCM 11576 T 5DSM 14884 T ). INTRODUCTIONA number of aerobic thermophiles have been isolated from a variety of geothermal environments such as hot springs, solfataric fields and hydrothermal vents throughout the world (Brock & Freeze, 1969;Brock et al., 1972;Grogan et al., 1990;Huber et al., 1992; Sako et al., 1996a Sako et al., , b, 2001). Members of the genus Thermus are probably the most frequently isolated extremely thermophilic aerobes from terrestrial hot-water environments. Although some strains grow mixotrophically (Skirnisdottir et al., 2001), almost all strains of the genus Thermus are obligate heterotrophs that live in various terrestrial hot environments at temperatures higher than about 55˚C and neutral to alkaline pH (Brock & Boylen, 1973;Pask-Hughes & Williams, 1975; Kristjánsson & Alfredsson, 1983;Williams & da Costa, 1992). Under anaerobic conditions, some strains of the genus Thermus are able to grow with NO { 3 , Fe(III) and S 0 as terminal electron acceptors instead of O 2 (Williams & da Costa, 1992;Sharp et al., 1995;Kieft et al., 1999).In deep-sea hydrothermal vent environments, however, most thermophiles had been thought to be strict anaerobes until the recent discovery of facultatively aerobic thermophiles from deep-sea hydrothermal vent chimneys (Blöchl et al., 1997; Reysenbach et al., 2000a). In addition, many strictly aerobic and thermophilic bacterial strains, including Thermus thermophilus Gy1211, have been isolated from deep-sea hydrothermal vent environments in the MidAtla...

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Marinithermus hydrothermalis gen. nov., sp. nov., a strictly aerobic, thermophilic bacterium from a deep-sea hydrothermal vent chimney

Sako

Nakagawa

Takai³

et al. 2003

International Journal of Systematic and Evolutionary Microbiology

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“…Although the physiology and genetics of the genus Thermus have been studied for three decades, strains showing this metabolic versatility have not previously been reported. Most strains of Thermus have been described as obligate aerobes (7), with a few being noted to reduce nitrate to nitrite (41,42,48,56).…”

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confidence: 99%

Dissimilatory Reduction of Fe(III) and Other Electron Acceptors by a Thermus Isolate

Kieft

Fredrickson

Onstott

et al. 1999

Appl Environ Microbiol

246

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A thermophilic bacterium that can use O2, NO3 −, Fe(III), and S0 as terminal electron acceptors for growth was isolated from groundwater sampled at a 3.2-km depth in a South African gold mine. This organism, designated SA-01, clustered most closely with members of the genusThermus, as determined by 16S rRNA gene (rDNA) sequence analysis. The 16S rDNA sequence of SA-01 was >98% similar to that ofThermus strain NMX2 A.1, which was previously isolated by other investigators from a thermal spring in New Mexico. Strain NMX2 A.1 was also able to reduce Fe(III) and other electron acceptors. Neither SA-01 nor NMX2 A.1 grew fermentatively, i.e., addition of an external electron acceptor was required for anaerobic growth.Thermus strain SA-01 reduced soluble Fe(III) complexed with citrate or nitrilotriacetic acid (NTA); however, it could reduce only relatively small quantities (0.5 mM) of hydrous ferric oxide except when the humic acid analog 2,6-anthraquinone disulfonate was added as an electron shuttle, in which case 10 mM Fe(III) was reduced. Fe(III)-NTA was reduced quantitatively to Fe(II); reduction of Fe(III)-NTA was coupled to the oxidation of lactate and supported growth through three consecutive transfers. Suspensions ofThermus strain SA-01 cells also reduced Mn(IV), Co(III)-EDTA, Cr(VI), and U(VI). Mn(IV)-oxide was reduced in the presence of either lactate or H2. Both strains were also able to mineralize NTA to CO2 and to couple its oxidation to Fe(III) reduction and growth. The optimum temperature for growth and Fe(III) reduction by Thermus strains SA-01 and NMX2 A.1 is approximately 65°C; their optimum pH is 6.5 to 7.0. This is the first report of a Thermus sp. being able to couple the oxidation of organic compounds to the reduction of Fe, Mn, or S.

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“…The enrichment medium is based on that used by Brock and Freeze (6), in which tryptone and yeast extract were replaced by 0.01% (wt/vol) casein. This defined minimal medium contained Nitsch's trace elements solution and Castenholtz basal salts (25). After solubilization of casein at high pH, the medium was adjusted to pH 7.6 and sterilized by filtration through 0.22-m (pore-size) filters.…”

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confidence: 99%

Use of a Packed-Column Bioreactor for Isolation of Diverse Protease-Producing Bacteria from Antarctic Soil

Wéry

Gerike

Sharman

et al. 2003

Appl Environ Microbiol

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Seventy-five aerobic heterotrophs have been isolated from a packed-column bioreactor inoculated with soil from Antarctica. The column was maintained at 10°C and continuously fed with a casein-containing medium to enrich protease producers. Twenty-eight isolates were selected for further characterization on the basis of morphology and production of clearing zones on skim milk plates. Phenotypic tests indicated that the strains were mainly psychrotrophs and presented a high morphological and metabolical diversity. The extracellular protease activities tested were optimal at neutral pH and between 30 and 45°C. 16S ribosomal DNA sequence analyses showed that the bioreactor was colonized by a wide variety of taxons, belonging to various bacterial divisions: ␣-, ␤-, and ␥-Proteobacteria; the Flexibacter-Cytophaga-Bacteroides group; and high G؉C grampositive bacteria and low G؉C gram-positive bacteria. Some strains represent candidates for new species of the genera Chryseobacterium and Massilia. This diversity demonstrates that the bioreactor is an efficient enrichment tool compared to traditional isolation strategies.In the laboratory, microorganisms are generally cultivated as cell suspensions in liquid media. However, their natural environments are often more complex, and most microorganisms are members of mixed populations, growing frequently in a nearly static situation (e.g., embedded in soil or as biofilms) resulting from the passage of an aqueous stream of dissolved gases and nutrients over them. A wide variety of surfaces are available in natural environments for attachment and colonization by microorganisms, and these attached bacteria are often more active than free cells (29).Developing new strategies to recover the microbial population that is not accessible by using classical enrichment techniques has become a real issue for microbiologists. Molecular studies of microbial diversity have shown that these "not yet cultivated" microorganisms can correspond to 99% of the total microbial population (2). Furthermore, access to this reservoir of genetic and metabolic diversity is of interest in areas such as food production, medicine, bioremediation of waste materials, and agriculture. In particular, there is an important biotechnological interest in the isolation of extremophilic microorganisms that are adapted to growth under extreme conditions of temperature, pH, salinity, pressure, and/or in the presence of radioactivity or high concentrations of metal. These extremophiles present a commercial potential for various industries and products, including agricultural applications, chemical synthesis, laundry detergents, and pharmaceuticals (22).In the present study, microrganisms were enriched by using a reactor designed to mimic natural ecosystems. This reactor contained a column filled with packing to allow microbial colonization and was fed by culture medium in a slow upflow mode. It was used in an attempt to isolate microorganisms growing at low temperatures and producing cold-active enzymes. Psychrophiles ar...

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Physiology and Metabolism of Thermus

Cited by 6 publications

References 96 publications

Marinithermus hydrothermalis gen. nov., sp. nov., a strictly aerobic, thermophilic bacterium from a deep-sea hydrothermal vent chimney

Marinithermus hydrothermalis gen. nov., sp. nov., a strictly aerobic, thermophilic bacterium from a deep-sea hydrothermal vent chimney

Dissimilatory Reduction of Fe(III) and Other Electron Acceptors by a Thermus Isolate

Use of a Packed-Column Bioreactor for Isolation of Diverse Protease-Producing Bacteria from Antarctic Soil

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