南极乔治王岛陆地土壤和潮间带放线菌多样性及其抑菌活性研究

Phylogenetic diversity analysis and antimicrobial activity of the terrestrial and intertidal zone of the King George Island at the Western Antarctic

目的系统研究南极乔治王岛陆地土壤和潮间带中放线菌的多样性,并对分离菌株拮抗临床多重耐药菌活性进行筛选。方法利用放线菌门特异引物扩增16SrDNA序列,构建放线菌16SrDNA基因克隆文库,对文库进行多样性指数分析和系统发育分析。采用琼脂块扩散法以3株临床多重耐药菌为指示菌,筛选具有高抑菌活性的潜在药用放线菌。结果土壤放线菌文库和潮间带放线菌文库的覆盖率分别为54.55%和87.2%,陆地土壤中放线菌群落以放线菌纲为优势菌,潮间带样品中酸微菌纲占据明显优势。陆地土壤中的放线菌分布于10个目16个科中,潮间带底泥中放线菌则分布于7个目13个科中。纯培养得到141株放线菌,其中从陆地样品中分离得到93株菌,分布于放线菌纲的7个属17个种中,从潮间带样品中分离得到41株菌,分布于5个属10个种中。有17株具有显著抑菌效果的菌株,其中4株菌抑菌活性最强,可强烈抑制3株多重耐药菌。结论南极乔治王岛陆地土壤和潮间带底泥环境中蕴涵着丰富且多样的放线菌资源,陆地土壤中放线菌的多样性要高于潮间带底泥中放线菌的多样性。南极链霉菌和诺卡氏菌具有较强的拮抗多重耐药菌的活性,具有深一步研究的价值。

Objective To analyze the actinobacterial diversity of the soil and intertidal zone sediment of the King George Island and to access the antimicrobial activities of the Antarctic actinomycetes against multiple resistant bacteria.Methods Actinobacteria-specific 16 SrDNA gene clone library was constructed.Representative clones were sequenced and placed into operational taxonomic unit（OTU）groups according to the 16 SrDNA sequence similarity.Diversity statistics was analyzed using SPADE analysis software.8selective media were used to isolate actinomycetes strain.Agar diffusion method was used to evaluate the antimicrobial activities of the strains obtained.Results The values of coverage of 16 SrDNA gene clone libraries of soil and intertidal sediments were 54.55% and 87.2%,respectively.The dominant actinobacteria in soil and the intertidal sediments were Class Actinobacteria and Class Acidimicrobiia,respectively.93 strains were isolated from soil and classified into 7genera while 41 strains from intertidal zone sediment belonging to 5genera.17 strains exhibited antimicrobial activity while 4stains showed strong activity against 3 multiple resistant bacteria.Conclusion There were abundant and diverse actinobacteria in terrestrial and intertidal zone of the King George Island at the Western Antarctic.Antarctic Streptomyces and Nocardia strains could be important resources for new antimicrobial metabolites.