威海海域柄海鞘和史氏菊海鞘来源的海洋放线菌多样性及活性菌株筛选

Actinomycetes is a kind of important source of new medicines. Half of bioactive natural products are produced by actinomycetes. Ascidian is one of the main marine animals from which many kinds of marine natural products are isolated. Ascidians are filter feeders and are associated with diverse populations of microorganisms. Therefore isolation of actinomycetes from ascidians is an important way to obtain and develop the marine actinomycete. The natural products and microorganisms isolated from different kinds of ascidians are different. Therefore we should do research and develop the ascidians and associated microorganism in order to find new natural products. A solitary ascidian Styela clava and a colonial ascidian Botrylloides schlosseri are two kinds of the main species of ascidians from Weihai area of Shandong province.The isolation and cultural methods will be studied to obtain many kinds of marine actinomycetes from this two kinds of ascidians.The diversity of actinomycetes associated with ascidians are studied to estimate the species composition and phylogenetic diversity of actinomycetes. The difference of phylogenetic diversity of actinomycetes assciated with two kinds of ascidians are studied and show that the actinomycetic speccies is special to the host.These results will be an important basis to illuminate the relationship between the ascidians and the actinomycetes.The potential antimicrobial activities and cytotoxic activities of the isolated marine actinomycetic strains are screened. Actinomycetic strains with stronge bioactivites may be developed as promising sources for the discovery of novel marine natural products.

放线菌是一类重要的药源微生物，半数以上的活性天然产物都是来源于放线菌。海鞘是目前国际上发现天然产物最多的海洋动物之一，海鞘底栖滤食的特性使其体内富集了大量的微生物，从海鞘中分离放线菌将是获得和应用海洋放线菌资源的一条重要途径。不同种类海鞘来源的天然产物和海洋微生物有很大的差别，因此对威海海域海鞘及其微生物资源进行系统的开发和利用是发现新天然产物的途径。本研究从山东威海海域海鞘优势种中分别选择单海鞘中的柄海鞘和复海鞘中的史氏菊海鞘作为研究对象，系统研究海鞘中海洋放线菌的分离方法，以获得更多的海洋放线菌菌株。通过对每种海鞘中海洋放线菌多样性的研究，了解海鞘中放线菌的种群结构组成，通过比较两种海鞘的海洋放线菌多样性差异，了解海洋放线菌对宿主的特异性，为进一步研究海鞘与海洋放线菌共附生关系提供重要依据。利用抗菌和抗肿瘤模型筛选具有较好生理活性的海洋放线菌菌株，为海洋微生物天然产物研究提供新资源。

海鞘是目前国际上发现天然产物最多的海洋动物之一，海鞘底栖滤食的特性使其体内富含了大量的微生物，许多直接或间接证据表明，海鞘中分离到的很多次级代谢产物都是由其体内的共生微生物产生的。不同地点和不同种类海鞘来源的海洋微生物和天然产物有一定的差别，因此对温带海域的海鞘来源可培养微生物资源进行系统的研究和开发是发现新天然产物的重要途径。本研究以我国黄海北部山东威海海域的2个地点3种海鞘样品为研究对象，系统研究了海鞘中海洋细菌的分离方法，共分离到811株细菌，其中放线菌241株。选取其中的513株进行16S rRNA序列的测定，它们属于5个门38个科64个属；不同地点不同种类海鞘样品中细菌的群落结构组成和多样性不同。海鞘来源的811个菌株的活性筛选结果表明，347株海鞘来源细菌对多种革兰氏阴性菌、革兰氏阳性菌、人病原真菌和水产动物病原细菌都表现出一定的抑制作用，尤其是对革兰氏阳性菌的抗性较好；183株海鞘来源细菌的发酵产物粗提物对人肝癌细胞株Bel-7402或人宫颈癌细胞株HeLa表现出较好的抑制作用。结果表明，海鞘来源细菌多样性丰富且可作为发现新颖生物活性物质的潜在资源。本研究为更好地开发利用海鞘微生物资源和发现新的活性天然产物提供了研究基础。在项目资助下已发表SCI论文1篇，培养硕士研究生3名。