title: Diversity and bioprospecting of culturable actinomycetes from marine sediment of the Yellow Sea, China.
abstract: Marine actinomycetes are a potential source of a wide variety of bioactive natural products. In this work, seven pretreatments, three selective isolation media, and five artificial seawater concentrations were used to isolate actinomycetes from the sediments collected from Yellow Sea, China. Statistical analysis showed that only the isolation medium strongly affected the total and bioactive numbers of actinomycete isolates. A total of 613 actinobacterial strains were isolated and screened for antimicrobial activities; 154 isolates showed activity against at least one of nine test drug-resistant microorganisms. Eighty-nine representatives with strong antimicrobial activity were identified phylogenetically based on 16S rRNA gene sequencing, which were assigned to five different actinomycete genera Streptomyces, Kocuria, Saccharomonospora, Micromonospora, and Nocardiopsis. Using PCR-based screening for six biosynthetic genes of secondary metabolites, all 45 isolates with acute activity have at least one biosynthetic gene, 28.8 % of which possess more than three biosynthetic genes. As a case, strain SMA-1 was selected for antimicrobial natural product discovery. Three diketopiperazine dimers including a new compound iso-naseseazine B (1) and two known compounds naseseazine B (2) and aspergilazine A (3) were isolated by bioassay-guided separation. These results suggested that actinomycetes from marine sediments are a potential resource of novel secondary metabolites and drugs.
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Xiong
authors.forename: Qiao-Xia
authors.initials: QX
authors.lastname: Liu
authors.forename: Zhao-Long
authors.initials: ZL
authors.lastname: Pan
authors.forename: Na
authors.initials: N
authors.lastname: Zhao
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Feng
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
mesh_terms: D039903:Actinobacteria / Q000145:classification* / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D001419:Bacteria / Q000187:drug effects; D044822:Biodiversity; D001688:Biological Products / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D065132:Bioprospecting; D002176:Candida albicans / Q000187:drug effects; D002681:China; D017077:Culture Media, Conditioned / Q000494:pharmacology; D054659:Diketopiperazines / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D019015:Geologic Sediments / Q000382:microbiology*; D009792:Oceans and Seas; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D001688:Biological Products; D017077:Culture Media, Conditioned; D054659:Diketopiperazines; D012336:RNA, Ribosomal, 16S