海南三亚红树林放线菌多样性及抗菌活性

Diversity and anti-microbial activity of actinobacteria isolated from mangrove in Sanya of Hainan province

目的研究海南三亚红树林底泥样品中放线菌的多样性及抗菌活性,以期发现可以产生新颖活性物质的药用放线菌资源。方法采用11种分离培养基以稀释涂布法对样品中的放线菌进行选择性分离;对分离菌株的16S rRNA基因序列进行扩增、比对,开展多样性分析;放线菌发酵液经乙酸乙酯萃取,采用纸片法对粗提物进行抗菌活性筛选;同时对放线菌的生物合成基因NRPS、PKS I和PKS II进行筛选。结果共分离到149株放线菌,它们分布于6个目12个科16个属,其中小单孢菌属为优势菌属;菌株MG16072的16S rRNA基因序列与最近有效菌株Actinomadura hallensis H647-1T的相似率为97.94%,为潜在Actinomadura属新种;抗菌活性检测结果显示,有20株放线菌至少对1株检定菌具有抗菌活性;NRPS、PKS I、PKS II基因筛选结果显示,有82株放线菌至少含有1种生物合成基因。结论海南三亚红树林含有丰富的药用放线菌资源,具有从中发现新颖活性物质的潜力。

Objective The research aimed to study the diversity and anti-microbial activity of actinobacteria isolated from sediments of mangrove in Sanya, Hainan. Methods Actinobacteria were isolated using dilution plating technique with 11 different isolation media. Diversity of actinobacteria was analyzed based on 16S rRNA gene sequence. Fermentation broths of actinobacteria were extracted by ethyl acetate. Antibacterial and antifungal assay of extracts were tested by disk diffusion method. Furthermore, the screening of NRPS, PKS Ⅰ and PKS Ⅱ genes was carried out by PCR method. Results The 149 actinobacteria isolates were distributed in 16 genera affiliated with 12 families of 6 orders, among them, Micromonospora are the dominant genus. The 16S rRNA sequence similarity between strain MG16072 and the nearest strain Actinomadura hallensis （H647-1^T DQ076484） in EzBioCloud database was 97.94%, which indicated that strain MG16072 is a potential new species of Actinomadura. 20 strains showed antibacterial and/or antifungal activities, and 82 strains carried at least one of NRPS, PKS Ⅰ and PKS Ⅱ genes. Conclusion Mangrove in Sanya are rich in medicinal actinobacteria, which could be a potential source for the discovery of new bioactive natural products.