西藏湖泊放线菌的分离鉴定及抗菌活性测定

Isolation,Identification and Antimicrobial Activity Determination of Actinobacteria from the Lakes in Tibet

勘探西藏湖泊沉积物样品中放线菌资源并进行抗菌活性研究,以期发现可以产生新颖活性物质的药用放线菌资源。采用4种分离培养基,以稀释涂布法对西藏地区7个湖泊沉积物样品中的放线菌进行分离,通过分离菌株16S rRNA基因序列分析确定种属分类。采用纸片扩散法进行体外抗菌活性测定,以感染病原菌的秀丽隐杆线虫模型进行体内抗菌活性测定。结果显示,分离获得73株放线菌,分属于4个目5个科8个属,其中链霉菌属和小单孢菌属为优势菌属。至少对一种检定菌表现为阳性的菌株有55株,阳性率为75.3%。8株放线菌具有线虫体内抗菌活性,其中菌株PF188的体内外抗菌活性较好,其16S rRNA基因序列与最近有效菌株Nonomuraea guangzhouensis NEAU-ZJ3^T的相似度为98.13%,为Nonomuraea属潜在新种。西藏湖泊沉积物含有丰富的放线菌资源,是新抗生素发现的潜在药源。

To study the diversity and antimicrobial activity of actinobacteria isolated from the sediment samples of lakes in Tibet aims to discover the medical actinobacteria producing novel active materials.Seven sediment samples were collected from lakes in Tibet,and from which actinobacteria were isolated using dilution plating method with 4 different media and then identified by 16 S rRNA sequence analysis.Antimicrobial in vitro activities of the isolates were tested by paper disk diffusion method.In vivo activities of the isolates were evaluated for their ability to rescue Caenorhabditis elegans infected with tested pathogens.Results showed that the 73 actinobacteria were distributed in 8 genera affiliated with 5 families of 4 orders,Streptomyces and Micromonospora of them were the dominant genera.The 55 of 73 strains demonstrated positive results in antimicrobial assay,and the positive rate was 75.3%.Eight isolates presented fine antibacterial activity in vivo based on C.elegans infected with pathogens.Strain PF188 showed favorable antimicrobial activity both in vivo and in vitro,and deserved further research.The 16S rRNA sequence similarity between strain PF188 and the nearest Nonomuraea guangzhouensis NEAU-ZJ3^T was 98.13%,indicating that strain PF188 is a potential new species of Nonomuraea.The sediment samples from lakes in Tibet are rich in cultivable actinobacteria,which could be a potential source for the discovery of new antibiotics.