Exploration of Diverse Secondary Metabolites From Streptomyces sp. YINM00001, Using Genome Mining and One Strain Many Compounds Approach.

A talented endophytic bacteria strain YINM00001, which showed strong antimicrobial activity and multiple antibiotic resistances, was isolated from a Chinese medicinal herb Peperomia dindygulensis Miq. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strain was closely related to Streptomyces anulatus NRRL B-2000T (99.93%). The complete genome of strain YINM00001 was sequenced. The RAxML phylogenomic tree also revealed that strain YINM00001 was steadily clustered on a branch with strain Streptomyces anulatus NRRL B-2000T under the 100 bootstrap values. The complete genome of strain YINM00001 consists of an 8,372,992 bp linear chromosome (71.72 mol% GC content) and a 317,781 bp circular plasmid (69.14 mol% GC content). Genome mining and OSMAC approach were carried out to investigate the biosynthetic potential of producing secondary metabolites. Fifty-two putative biosynthetic gene clusters of secondary metabolites were found, including the putative cycloheximide, dinactin, warkmycin, and anthracimycin biosynthetic gene clusters which consist with the strong antifungal and antibacterial activities exhibited by strain YINM00001. Two new compounds, peperodione (1) and peperophthalene (2), and 17 known compounds were isolated from different fermentation broth. Large amounts and high diversity of antimicrobial and/or anticancer compounds cycloheximide, dinactin, anthracimycin, and their analogs had been found as predicted before, which highlights strain YINM00001 as an ideal candidate for further biosynthetic studies and production improvement of these valuable compounds. Meanwhile, several gene clusters that were highly conserved in several sequenced actinomycetes but significantly different from known gene clusters might be silent under proceeding fermentation conditions. Further studies, such as heterologous expression and genetic modification, are needed to explore more novel compounds from this talented endophytic Streptomyces strain.

A new phenylspirodrimane dimer from the fungus Stachybotrys chartarum.

A new phenylspirodrimane dimer, named stachartarin A (1), was isolated from cultures of the tin mine tailings-associated fungus Stachybotrys chartarum. Its structures were elucidated by means of spectroscopic methods. At the same time, the compound was tested for its cytotoxicity against HL-60, SMMC-7721, A-549, MCF-7, and SW480 cells.

Olivibacter flavus sp. nov., a novel endophytic bacterium isolated from the root of Camellia sinensis.

A novel Gram-negative rod, endophytic bacterium, designated strain TMCC 8258T, was isolated from the root of Camellia sinensis collected from Puer, south-west China. Comparative 16S rRNA gene sequence analysis showed that the strain belongs to the family Sphingobacteriaceae and a neighbour-joining phylogenetic tree suggested that strain TMCC 8258T formed a cluster with the type strain of Olivibacter ginsengisoli (showed the highest 16S rRNA gene sequence similarity of 95.8%). Chemotaxonomic data [major fatty acid iso-C15:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), iso-C17:0 3-OH and major respiratory quinone MK-7] confirmed the affiliation of strain TMCC 8258T to the genus Olivibacter. The G + C content was 39.1 mol %. The results of the phylogenetic analysis, together with the physiological, morphological and biochemical tests, suggested that strain TMCC 8258T should be classified as representing a novel species of the genus Olivibacter, for which the name Olivibacter flavus is proposed. The type strain is TMCC 8258T (=CGMCC 1.16141 = KCTC 42683).