RESUMEN
A thermotolerant, Gram-positive, aerobic, endospore-forming, acidophilic bacterium (strain Kr1T) was isolated from the pulp of a gold-containing sulfide concentrate processed at 40 degrees C in a gold-recovery plant (Siberia). Cells of strain Kr1(T) were straight to slightly curved rods, 0.8-1.2 microm in diameter and 1.5-4.5 microm in length. Strain Kr1T formed spherical and oval, refractile, subterminally located endospores. The temperature range for growth was 20-60 degrees C, with an optimum at 40 degrees C. The pH range for growth on medium containing ferrous iron was 1.2-2.4, with an optimum at pH 2.0; the pH range for growth on medium containing S0 was 2.0-5.0, with an optimum at pH 2.5. Strain Kr1T was mixotrophic, oxidizing ferrous iron, S0, tetrathionate or sulfide minerals as energy sources in the presence of 0.02 % yeast extract or other organic substrates. The G+C content of the DNA of strain Kr1T was 48.2+/-0.5 mol%. Strain Kr1T showed a low level of DNA-DNA reassociation with the known Sulfobacillus species (11-44 %). 16S rRNA gene sequence analysis revealed that Kr1T formed a separate phylogenetic group with a high degree of similarity between the nucleotide sequences (98.3-99.6 %) and 100 % bootstrap support within the phylogenetic Sulfobacillus cluster. On the basis of its physiological properties and the results of phylogenetic analyses, strain Kr1T can be affiliated to a novel species of the genus Sulfobacillus, for which the name Sulfobacillus thermotolerans sp. nov. is proposed. The type strain is Kr1T (=VKM B-2339T=DSM 17362T).
Asunto(s)
Bacilos Grampositivos Formadores de Endosporas/clasificación , Bacilos Grampositivos Formadores de Endosporas/aislamiento & purificación , Composición de Base , Metabolismo de los Hidratos de Carbono , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Microbiología Ambiental , Compuestos Ferrosos/metabolismo , Genes de ARNr , Ácido Glutámico/metabolismo , Glutatión/metabolismo , Oro , Bacilos Grampositivos Formadores de Endosporas/citología , Bacilos Grampositivos Formadores de Endosporas/fisiología , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Oxidación-Reducción , Filogenia , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Sulfuros/metabolismo , Azufre/metabolismo , Temperatura , Ácido Tetratiónico/metabolismoRESUMEN
Comparative analysis of 16S rRNA gene sequences, DNA-DNA hybridization data and phenotypic properties revealed that 'Sulfobacillus thermosulfidooxidans subsp. thermotolerans' strain K1 is not a member of the genus Sulfobacillus. Phylogenetically, strain K1 is closely related to unclassified strains of the genus Alicyclobacillus: the 16S rRNA gene sequence of strain K1 is similar to that of Alicyclobacillus sp. AGC-2 (99.6 %), Alicyclobacillus sp. 5C (98.9 %) and Alicyclobacillus sp. CLG (98.6 %) and bacterium GSM (99.1 %). The 16S rRNA gene sequence similarity values for strain K1 and species of the genus Alicyclobacillus with validly published names were in the range 92.1-94.6 %, and for S. thermosulfidooxidans VKM B-1269(T) the value was 87.7 %. Sulfobacillus disulfidooxidans SD-11(T) was also phylogenetically related to strain K1 (92.6 % sequence similarity) and thus belonged to the genus Alicyclobacillus. Chemotaxonomic data, such as the major cell-membrane lipid components of strains K1 and SD-11(T) (omega-alicyclic fatty acids) and the major isoprenoid quinone (menaquinone MK-7) of strain K1, supported the affiliation of strains K1 and SD-11(T) to the genus Alicyclobacillus. Physiological and molecular biological tests allowed genotypic and phenotypic differentiation of strains K1 and SD-11(T) from the nine Alicyclobacillus species with validly published names. The G+C content of the DNA of strain K1 was 48.7+/-0.6 mol%; that of strain SD-11(T) was 53+/-1 mol%. DNA-DNA reassociation studies showed low relatedness (22 %) between strains K1 and SD-11(T), and even lower relatedness (3-5 %) between these strains and Alicyclobacillus acidocaldarius subsp. acidocaldarius ATCC 27009(T), DSM 446(T). DNA reassociation of strains K1 and SD-11(T) with Alicyclobacillus cycloheptanicus DSM 4006(T) gave values of 15 and 21, respectively. Based on the phenotypic and phylogenetic characteristics of strains K1 and SD-11(T), Alicyclobacillus tolerans sp. nov. (type strain, K1(T)=VKM B-2304(T)=DSM 16297(T)) and Alicyclobacillus disulfidooxidans comb. nov. (type strain, SD-11(T)=ATCC 51911(T)=DSM 12064(T)) are proposed.
Asunto(s)
Bacilos Grampositivos Formadores de Endosporas/clasificación , Bacilos Grampositivos Formadores de Endosporas/genética , ADN Bacteriano/análisis , ADN Ribosómico/análisis , Genes de ARNr , Bacilos Grampositivos Formadores de Endosporas/química , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Fenotipo , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
Two strains of obligate chemolithoautotrophic sulfur-oxidizing bacteria were isolated from soda-lake sediments by enrichment culture with thiocyanate and nitrate at pH 9.9. The isolates were capable of growth with thiocyanate or thiosulfate as electron donor, either aerobically or anaerobically, and with nitrate or nitrite as electron acceptor. Cyanate was identified as an intermediate of thiocyanate oxidation, while sulfate, ammonia and dinitrogen gas were the final products. The anaerobic growth on thiocyanate plus nitrate was much slower (mu(max)=0.006 h(-1)) than on thiosulfate plus nitrate (mu(max)=0.02 h(-1)), while growth yields were similar (4.8 and 5.1 g protein mol(-1), respectively). On the basis of their phenotypic and genetic properties, strains ARhD 1(T) and ARhD 2 are described as a novel species of the genus Thialkalivibrio, with the highest similarity to Thialkalivibrio denitrificans. The name Thialkalivibrio thiocyanodenitrificans sp. nov. is proposed for this novel species.
Asunto(s)
Gammaproteobacteria/clasificación , Gammaproteobacteria/crecimiento & desarrollo , Nitratos/metabolismo , Cloruro de Sodio/metabolismo , Azufre/metabolismo , Tiocianatos/metabolismo , Anaerobiosis , Medios de Cultivo , Agua Dulce/microbiología , Gammaproteobacteria/genética , Gammaproteobacteria/metabolismo , Sedimentos Geológicos/microbiología , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Oxidación-Reducción , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
Strain ALEN 2(T) was isolated from a mixed culture capable of complete autotrophic denitrification with thiosulfate as electron donor at pH 10; the mixed culture was enriched from sediment from Lake Fazda (Wadi Natrun, Egypt), a hypersaline alkaline lake. The isolate had large, non-motile, coccoid or barrel-shaped cells with intracellular sulfur globules. The bacterium was obligately chemolithoautotrophic. It grew with reduced sulfur compounds aerobically and anaerobically with nitrate as electron acceptor, nitrate being reduced to nitrite. It was moderately halophilic and obligately alkaliphilic. On the basis of genetic analysis and its unique phenotype, strain ALEN 2(T) (=DSM 14787(T)=UNIQEM 213(T)) is proposed as the type strain of a novel species of the genus Thialkalivibrio, Thialkalivibrio nitratireducens.
Asunto(s)
Chromatiaceae/clasificación , Nitratos/metabolismo , Filogenia , Microbiología del Agua , Chromatiaceae/citología , Chromatiaceae/aislamiento & purificación , Chromatiaceae/metabolismo , Egipto , Sedimentos Geológicos/microbiología , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Oxidación-Reducción , Consumo de Oxígeno , Sulfatos/metabolismo , Azufre/metabolismoRESUMEN
Two strains of haloalkaliphilic, obligately autotrophic, sulfur-oxidizing bacteria were isolated from the oxygen-sulfide interface water layer of stratified alkaline and saline Mono Lake, California, USA. Strain ALM 1T was a dominant species in enrichment on moderate-saline, carbonate-buffered medium (0.6 M total Na+, pH 10) with thiosulfate as an energy source and nitrate as a nitrogen source. Cells of ALM 1T are open ring-shaped and are non-motile. It has a high growth rate and activity of thiosulfate and sulfide oxidation and very low sulfur-oxidizing activity. Genetic comparison and phylogenetic analysis suggested that ALM 1T (= DSM 14477T = JCM 11371T) represents a new species of the genus Thioalkalimicrobium in the gamma-Proteobacteria, for which the name Thioalkalimicrobium cyclicum sp. nov. is proposed. Another Mono Lake isolate, strain ALM 2T, dominated in enrichment on a medium containing 2 M total Na+ (pH 10). It is a motile vibrio which tolerates up to 4 M Na+ and produces a membrane-bound yellow pigment. Phylogenetic analysis placed ALM 2T as a member of genus Thioalkalivibrio in the gamma-Proteobacteria, although its DNA hybridization with the representative strains of this genus was only about 30%. On the basis of genetic and phenotypic properties, strain ALM 2T (= DSM 14478T = JCM 11372T) is proposed as Thioalkalivibrio jannaschii sp. nov..
Asunto(s)
Agua Dulce/microbiología , Gammaproteobacteria/clasificación , Gammaproteobacteria/fisiología , Cloruro de Sodio/farmacología , Azufre/metabolismo , California , Medios de Cultivo , ADN Ribosómico/análisis , Gammaproteobacteria/genética , Gammaproteobacteria/ultraestructura , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Oxidación-Reducción , Fenotipo , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
An anaerobic enrichment medium (pH 10) with thiosulfate as electron donor and nitrate as electron acceptor was inoculated with sediment from soda lake Fazda (Wadi Natrun, Egypt); a novel strain, ALEN 1(T), was isolated from the subsequent enrichment culture. Cells of strain ALEN 1(T) had a spiral morphology (0.3-0.45 x 1-4 microm), were motile and had a single polar flagellum. Sphaeroplasts were formed by the cells and were rapidly lysed during prolonged aerobic incubation of cultures. Cells of strain ALEN 1(T) contained a membrane-associated yellow pigment. The metabolism of this novel organism was obligately chemolithoautotrophic, and thiosulfate or sulfide were utilized as electron donors. Washed cells of strain ALEN 1(T) oxidized thiosulfate, sulfide, polysulfide and elemental sulfur to sulfate. Best growth was observed when the strain was grown under micro-oxic conditions (1-2% O2 in gas phase), whereas growth was inhibited under fully oxic conditions. Nitrate was reduced to nitrite without growth of the novel organism, but other nitrogen oxides were not utilized as electron acceptors. Strain ALEN 1(T) was alkaliphilic and moderately halophilic. It grew between pH 8 and 10.4 (optimum around pH 10) with a salt concentration of between 0.3 and 1.5 M Na+ (optimum 0-5 M). The maximum growth rate (0.08 h(-1)) of the organism was achieved in a thiosulfate-limited micro-oxic continuous culture (pH 10). Phylogenetic analyses of the 16S rDNA sequences of strain ALEN 1(T) and its closest relatives demonstrated that this strain formed a deep branch within the gamma-Proteobacteria, with no obvious association to any described cluster of species/genera. On the basis of its unique physiological properties and distinct phylogenetic position, it is proposed that strain ALEN 1(T) (= DSM 14786(T) = UNICEM 212(T)) represents a novel genus within the gamma-Proteobacteria, for which the name Thioalkalispira is proposed. It is also proposed that the type species of this novel genus be named Thioalkalispira microaerophila.