Diversity, bioactivities, and metabolic potentials of endophytic actinomycetes isolated from traditional medicinal plants in Sichuan, China.

The present study was designed to determine the taxonomic diversity and metabolic activity of the actinomycetes community, including 13 traditional medicinal plants collected in Sichuan province, China, using multiple approaches such as morphological and molecular identification methods, bioactivity assays, and PCR screening for genes involved in antibiotics biosynthesis. 119 endophytic actinomycetes were recovered; 80 representative strains were chosen for 16S rRNA gene partial sequence analyses, with 66 of them being affiliated to genus Streptomyces and the remaining 14 strains being rare actinomycetes. Antimicrobial tests showed that 12 (15%) of the 80 endophytic actinomycetes displayed inhibitory effects against at least one indicator pathogens, which were all assigned to the genus Streptomyces. In addition, 87.5% and 58.8% of the isolates showed anticancer and anti-diabetic activities, respectively. Meanwhile, the anticancer activities of the isolates negatively correlated with their anti-diabetic activities. Based on the results of PCR screening, five genes, PKS-I, PKS-II, NRPS, ANSA, and oxyB, were detected in 55.0%, 58.8%, 90.0%, 18.8% and 8.8% of the 80 actinomycetes, respectively. In conclusion, the PCR screening method employed in the present study was conducive for screening and selection of potential actinomycetes and predicting potential secondary metabolites, which could overcome the limitations of traditional activity screening models.

Bacillus shacheensis sp. nov., a moderately halophilic bacterium isolated from a saline-alkali soil.

A moderately halophilic bacterium, strain HNA-14(T), was isolated from a saline-alkali soil sample collected in Shache County, Xinjiang Province. On the basis of the polyphasic taxonomic data, the isolate was considered to be a member of the genus Bacillus. The organism grew optimally at 30 °C and pH 8.0. It was moderately halophilic and its optimum growth occurred at 5-10% NaCl. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid and the predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0 and the polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and two unknown phospholipids. The G+C content of the genomic DNA was 48.6 mol%. Strain HNA-14(T) exhibited a low 16S rRNA gene sequence similarity of 96% with its nearest neighbors [Bacillus clausii KSM-K16 (96.5%), Bacillus xiaoxiensis DSM 21943(T)(96.2%), Bacillus clausii DSM 8716(T) (96.1%), Bacillus patagoniensis PAT05(T) (96.1%), Bacillus lehensis MLB-2(T) (96.0%), Bacillus oshimensis K11(T) (95.9%) and Bacillus hunanensis DSM 23008(T) (95.8%)] and the phenotypic characteristics indicate that strain HNA-14(T) can be distinguished from them. Therefore, a novel species of the genus Bacillus, Bacillus shacheensis sp. nov. (type strain, HNA-14(T) = KCTC 33145 = DSM 26902) is proposed.