RESUMO
Two novel thermophilic, spore-forming bacterial strains, T-11(T) and E-112(T), were isolated from hot springs in Tengchong and Eryuan counties of Yunnan province in south-west China. The strains were Gram-stain-positive rods, occurring singly or in chains. Growth of strain T-11(T) was observed between 30 and 75 °C (optimum 50 °C) and at pH 7-11 (optimum pH 8.5), while the temperature range for strain E-112(T) was 35-70 °C (optimum 55 °C) and the pH range was 7.0-11.0 (optimum pH 8.0). The DNA G+C contents of strains T-11(T) and E-112(T) were 41.1 and 42.6 mol%, respectively. On the basis of 16S rRNA gene sequence similarity, the two strains were shown to be related most closely to Anoxybacillus species. The chemotaxonomic characteristics [predominant isoprenoid quinone menaquinone 7 (MK-7); major fatty acids iso-C(15â:â0) and iso-C(17â:â0)] also supported the affiliation of strains T-11(T) and E-112(T) to the genus Anoxybacillus. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strains T-11(T) and E-112(T) from Anoxybacillus species with validly published names. Strains T-11(T) and E-112(T) therefore represent two novel species, for which the names Anoxybacillus tengchongensis sp. nov. (type strain T-11(T) =CCTCC AB209237(T) =KCTC 13721(T)) and Anoxybacillus eryuanensis sp. nov. (type strain E-112(T) =CCTCC AB209236(T) =KCTC 13720(T)) are proposed.
Assuntos
Anoxybacillus/classificação , Anoxybacillus/isolamento & purificação , Fontes Termais/microbiologia , Anoxybacillus/genética , Anoxybacillus/fisiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Filogenia , Quinonas/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Esporos Bacterianos/citologia , TemperaturaRESUMO
The geothermal sites near neutral and alkalescent thermal springs in Tengchong Rehai National Park were examined through cultivation-dependent approach to determine the diversity of thermophilic fungi in these environments. Here, we collected soils samples in this area, plated on agar media conducive for fungal growth, obtained pure cultures, and then employed the method of internal transcribed spacer (ITS) sequencing combined with morphological analysis for identification of thermophilic fungi to the species level. In total, 102 strains were isolated and identified as Rhizomucor miehei, Chaetomium sp., Talaromyces thermophilus, Talaromyces byssochlamydoides, Thermoascus aurantiacus Miehe var. levisporus, Thermomyces lanuginosus, Scytalidium thermophilum, Malbranchea flava, Myceliophthora sp. 1, Myceliophthora sp. 2, Myceliophthora sp. 3, and Coprinopsis sp. Two species, T. lanuginosus and S. thermophilum were the dominant species, representing 34.78% and 28.26% of the sample, respectively. Our results indicated a greater diversity of thermophilic fungi in neutral and alkaline geothermal sites than acidic sites around hot springs reported in previous studies. Most of our strains thrived at alkaline growth conditions.