两株红树林来源链霉菌的鉴定和抗菌活性研究

Identification and antibacterial activity of two mangrove-derived Streptomyces

目的对分离自广西茅尾海红树林根际土壤的两株链霉菌B353和B486进行鉴定和抗菌活性研究。方法采用4种培养基分离放线菌,ISP2培养基纯化菌株;通过PCR扩增和测序获得菌株16S rRNA基因序列;采用邻接法(Neighbor-Joining)来构建系统进化树;采用纸片扩散法(K-B法)测定其抗菌活性;观察两株链霉菌的形态特征;利用薄层色谱法(thin layer chromatography,TLC)对活性物质进行初步研究。结果经16S rRNA基因序列比对发现,菌株B353和B486可能是Streptomyces seoulensis NRRL B-24310T的两个变种。抗菌活性筛选表明,B353和B486这两株链霉菌对不同的鉴定菌株都有较好的抗菌活性,其中对金黄色葡萄球菌的抗菌活性较强。TLC的分析结果表明,链霉菌B353和B486产对金黄色葡萄球菌有活性的物质。结论分离自广西茅尾海红树林根际土壤的放线菌有较强抗菌活性,存在从中发现有着天然活性的新抗生素的潜力。

Aim To study and identify the antibacterial activity of two strains of Streptomyces(B353 and B486)collected from the roots of mangrove rhizosphere in Maowei Sea,Guangxi.Methods Actinobacteria were isolated with four different media and purified by ISP2 medium.Sequences of 16S rRNA gene obtained by PCR amplification were submitted to gene database for BLAST search.Phylogenetic tree was constructed by adjacency method,and homology analysis was carried out to study the diversity and novelty of actinobacteria.Disk diffusion method was used to test the antimicrobial activity.Morphological characteristics of two strains of Streptomyces B353 and B486 were observed.TLC was used to isolate and purify the active substance.Results Comparative analysis of 16S rRNA gene sequences showed that strains B353 and B486 might be two variants of Streptomyces seoulensis NRRL B-24310T.The antimicrobial activity screening showed that the two Streptomyces strains B353 and B486 had good antibacterial activity against different identified strains,among which the antibacterial activity against Staphylococcus aureus was strong.TLC analysis showed that Streptomyces B353 produced active substance against Staphylococcus aureus and Streptolyces B486 produced active substance against Staphylococcus aureus.Conclusions Two actinomycetes isolated from mangrove rhizosphere soils in Maowei Sea,Guangx and its fermentation products show significant antibacterial activity.Mangrove rhizosphere soils are rich in culturable medicinal actinobacteria,which could be a potential source for the discovery of new antibiotics,and deserves further research.