福建海参内源微生物多样性分析及益生菌抑菌机理初探

Biodiversity analysis and pathogen inhibition mechanism of the endogenous bacteria in Fujian Apostichopus japonicus

为探明福建吊笼养殖海参内源微生物群落结构及抑菌作用机理,采用16S r DNA序列同源性比对手段对分离自海参肠道中的优势菌株进行多样性分析,测定其中益生菌及其代谢产物脂肽类化合物的抑菌能力,并采用薄层色谱(TLC)初步确定其抑菌成分。结果表明,福建吊笼养殖海参肠道中共分离出95株优势菌株,包括31株潜在益生菌、37株潜在致病菌及27株普通肠道菌。微生物群落结构分析发现,高丰度假交替单胞菌属和不动杆菌属以及低丰度芽孢杆菌属是福建海参体表产生病灶的可能原因之一。以其中8株典型致病菌为指示菌,筛选出两株抑菌谱广且抑菌能力较强的益生菌菌株—解淀粉芽孢杆菌(Bacillus amyloliquefaciens)YD1及枯草芽孢杆菌(Bacillus subtilis)YK5,其脂肽类代谢产物的抑菌作用明显,初步确定其中的抑菌成分均为含有亲水性成分的环脂肽类化合物。本研究为开发新型微生态制剂和功能性益生菌提供了重要的理论支持。

For the purpose of exploring the microbial community structure and bacteriostasis mechanism of Fujian cage farming Apostichopus japonicus,diversity of the dominant strains isolated from the intestinal tracts of Apostichopus japonicus was analyzed using 16 S r DNA sequence homology comparison method.The bacteriostatic ability of probiotics and their metabolites lipopeptide compounds were determined,and their antibacterial components were preliminarily determined by thin layer chromatography（ TLC）..The results showed that 95 strains of dominant bacteria were isolated and purified,which included 31 strains of potential probiotics,37 strains of potential pathogens and 27 strains of common intestinal bacteria. Microbial community structure analysis found that the abundance of Pseudoalteromonas and Acinetobacter genera were higher while that of Bacillus genus was lower in diseased group than those in healthy group.It would be one of the possible causes of the body surface lesion of Fujian Apostichopus japonicus. Taking 8 strains of typical pathogenic strains as indicator bacteria,two probiotic strains with wide antimicrobial spectrum and high bacteriostatic ability were screened out,which were Bacillus amyloliquefaciens YD1 and Bacillus subtilis YK5. Their lipopeptide metabolites had obvious bacteriostatic effect. The bacteriostasis components were preliminarily determined to be cyclic peptides containing hydrophilic components.The study provided an important basis for the development of functional probiotics and novel microecologics.