北部湾近海珊瑚礁区系沉积物抗菌活性放线菌类群

Antibacterial Actinomycetes Community from Sediment of Coral Reefs in the Offshore Areas of Beibu Gulf

通过对大肠埃希菌和枯草芽胞杆菌抗菌活性初步筛选,从北部湾近海珊瑚礁区5个沉积物样品中成功分离得到51株具有不同抗菌活性的放线菌,其中9株具有较强抗菌能力。根据这9株放线菌的菌落和孢子形态,可确定它们都属于链霉菌属。RAPD-PCR分析表明这9株放线菌为6种不同类型,16S rDNA序列和系统发生树分析表明,9株放线菌可划分到4个大的类群6种不同类型,且结果显示RAPD-PCR聚类分析与16S rDNA序列聚类分析的结果具有较大的一致性。生理生化鉴定结果表明,分离株与亲缘关系最近的放线菌模式菌株的生理生化特征均存在差异,这说明分离株为放线菌新种的可能性比较大。这6种放线菌具有较为广谱的抑菌活性,并且抑菌活性均存在一定的差异,说明其可能分泌出多种结构功能不同的活性次生代谢产物。研究结果表明,广西北部湾近海珊瑚礁区系沉积物蕴藏着丰富的可供药物开发的放线菌资源。

Using antibacterial activity against E. coli and Bacillus subtilis as initial screening, 51 Actinomycetes strains possessing different antibacterial activities were isolated from 5 sediment samples of coral reefs in the offshore areas of Beibu Gulf, among them 9 strains showed comparatively strong antibacterial abilities. It could be determined that they belonged to the genus of Streptomyces based on their colonies and spores morphology. RAPD-PCR analysis indicated that the 9 strains also belonged to 6 types, 16S rDNA sequence and phylogenetic tree analysis indicated that the 9 strains could be divided into 6 different types of 4 major groups. And the results showed that RAPD-PCR cluster analysis had fairly large compatibility with 16S rDNA sequence cluster analysis. Physiological and biochemical identi-fication results showed that the isolates existed differences from Actinomyces model strain in physiological and biochem-ical features. This indicated that the isolates may likely be novel species of Actinomyces. These 6 Actinomyces strains had broad spectrum of antibacterial activity, and existed a certain differences in antibacterial activities, suggested that they may excrete secondary metabolites of multiple different structures and functions. The study results showed that sediment of coral reefs in the offshore areas of Beibu Gulf stores abundant source of Actinomycetes for medicine devel-opment.