智利海洋沉积物中放线菌多样性

【目的】认识智利海洋沉积物中放线菌的多样性。【方法】分别采用选择性分离培养和非培养的基于16SrRNA基因序列系统发育分析方法,对来自智利南部海域海洋沉积物中放线菌多样性进行研究。采用6种选择性分离培养基分离放线菌;利用放线菌特异性引物对样品总DNA进行16SrRNA基因序列扩增并构建了16SrRNA基因克隆文库。分别挑选不同培养特征的22株放线菌和59个基因克隆进行16SrRNA基因序列的系统进化分析;测定分离的放线菌对海水的依赖性及产生抗菌活性化合物的能力。【结果】共分离到328株放线菌;挑选的22株放线菌分别属于小单孢菌属、多形孢菌属、链霉菌属、迪茨氏菌属、气微菌属和短状杆菌属;挑取的59个克隆属于40个分类单元,其中60%分类单元属于放线菌门放线菌亚纲、酸微菌亚纲和红色杆菌亚纲,另外40%的分类单元在放线菌内形成几个独立的进化分支,有可能代表放线菌新类群。22株放线菌有19株具有抗菌活性,50%的生长依赖海水的放线菌也具有抗菌活性。【结论】智利海域沉积物存在丰富的放线菌系统发育多样性并能产生活性次级代谢产物,而且还蕴藏丰富的新类型的放线菌资源。

Actinobacterial diversity of marine sediment samples from Chile

Abstract: Objective] The aim of this study was to investigate actinobacterial diversity in Chilean marine sediments. Methods] Actinobacterial diversity in these sediments was investigated by selective isolation method, culture-independent method and phylogenetic analysis based on 16S rRNA gene sequences. Six selective media were used to isolate actinomycetes from sediment samples. The primers for the class Actinobacteria were used for Actinobacterial 16S rRNA gene amplification and then a clone library was constructed for the sediment sample btt. Twenty-two strains with different culture characteristics and 59 clones from sample btt were selected for 16S rRNA gene sequences analysis. To determine requirement for seawater each strain was grown on oatmeal agar prepared with deionized water and with seawater, respectively. Strains were screened for antibiotic activity against bacteria and fungi. Results] In total 328 actinomycetes were obtained. Twenty-two strains which were selected belonged to Streptomyces, Micromonospora, Polymorphospora, Aeromicrobium and Brachybacterium. Fifty-nine clones (40 OTUs) were sequenced, and 60% OTUs belonged to Actinobacteridae, Acidimicrobidae and Rubrobacteridae. The other 40% OTUs, which formed several distinct clades in phylogenetic tree among phylum Actinobacteria may represent new taxonomical groups. 50% of the 47 sea water dependant strains and nineteen strains out of the above 22 strains exhibited antimicrobial activity. Conclusion] There was abundant actinobacterial diversity in the marine sediments of Chile, and the result implied that there were large numbers of unknown actinobacterial groups in the sediments. Actinomycetes from Chilean marine sediments had the potential of producing bioactive secondary metabolites.