Genome mining of actinomycin shunt products from Kitasatospora sp. YINM00002.

Actinomycins are known for their anti-tumor, antibacterial and antiviral activities, and in particular for the ability of actinomycin D as a clinical drug to treat a variety of cancers. In our ongoing work to obtain novel natural products from endophytic actinomycetes derived from traditional Chinese herbs, we identified the potential to produce actinomycins in YINM00002, a Kitasatospora strain derived from Polygonatum kingianum. According to genome mining, we isolated actinomycins D and V (1 and 2) and small amounts of 4-methyl-3-hydroxyanthranilic acid (4-MHA) derivates (3 and 4) from strain fermentation broth. The presence of actinrhater A (3) and actinrhater B (4) reveals a mysterious shunt pathway in the early stages of actinomycin D biosynthesis. Our study provides a fresh perspective for further discovery and modification of novel actinomycins.

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.

Oceanobacillus salinisoli sp. nov., a bacterium isolated from saline soil of Turpan city in Xinjiang province, north-west China.

YIM B00359T, a novel bacterial strain was isolated from the saline soil of Turpan city in Xinjiang province, north-west China. The strain was Gram-stain-positive, motile, aerobic, produced oval subterminal endospores in swollen sporangia. The whole-cell hydrolysates contain meso-diaminopimelic acid as the cell-wall diamino acid, with xylose, glucose, and ribose as the major whole-cell sugars. The phospholipids are diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids, unidentified glycolipids, and one unidentified glycophospholipid. The predominant menaquinone is MK-7. The major fatty acids are anteiso-C15:0, iso-C14:0, iso-C15:0, and iso-C16:0. The DNA G + C content of the type strain is 37.5 mol%. Phylogenetic analysis indicated that the isolate belongs to the genus Oceanobacillus. However, it differed from its closest relatives, Oceanobacillus halophilus DSM 23996 T and Oceanobacillus senegalensis Marseille-P3587T in many physiological and chemotaxonomic characteristics. Based on comparative analysis of polyphasic taxonomic data, strain YIM B00359T represents a novel species of the genus Oceanobacillus, for which the name Oceanobacillus salinisoli sp. nov. is proposed. The type strain is YIM B00359T (= CGMCC 1.17509T = KCTC 43185T).