基于秀丽隐杆线虫模型的抗菌性海洋益生菌筛选及其机理研究

Side effects such as antibiotic-resistance brought on by the overuse of antibiotics have posed a tremendous threat on the health of human and farmed animals. As a potential alternative to antibiotic therapies, probiotics have been playing an increasingly important role in maintaining human health, animal farming and fishing. Thus, the rich microbes in sea that are currently underutilized have become an important source from which new probiotics can be developed. The objective of this project is to select marine probiotics which are able to protect Caenorhabditis elegans from the antibacterial activity of marine bacteria by establishing an anti-staphylococcus aureus model of Caenorhabditis elegans. The modern molecular biology technologies, such as fluorescence quantitative PCR, transcriptomic analysis method，and proteomic analysis method, were used to investigate the inhibitive effect of selected marine probiotics on the disease-leading factors of staphylococcus aureus. In addition, the mechanism through which those marine probiotics influenced the defense gene expression of Caenorhabditis elegans was also studied. By clarifying the protection mechanism of marine probiotics on Caenorhabditis elegans in a molecular regulation level, our study will reveal the interaction mechanism among Caenorhabditis elegans, marine probiotics and pathogenic bacteria. The results from this project will provide a theoretical and experimental basis for developing new marine probiotics, and a direction in which we human beings could take advantages of marine resources more efficiently in future.

过度使用抗生素所引起的副作用和细菌的耐药性对人类和养殖动物的健康构成了严重威胁。益生菌作为抗生素治疗的潜在替代品在人类健康和动物及渔业养殖中发挥着越来越重要的作用。海洋中丰富的尚未被利用的微生物资源成为开发新益生菌的重要来源。本项目拟通过建立秀丽隐杆线虫抗金黄色葡萄球菌筛选模型，从有抗菌活性的海洋细菌中筛选出对秀丽隐杆线虫具有保护效果的海洋益生菌。在研究中采用荧光定量PCR、转录组和蛋白组分析等现代分子生物学技术，探讨海洋益生菌在秀丽隐杆线虫体内对金黄色葡萄球菌致病因素的抑制作用；探究海洋益生菌对秀丽隐杆线虫防御基因表达的影响，进而阐明海洋益生菌保护秀丽隐杆线虫抗金黄色葡萄球菌的分子调控机理，揭示秀丽隐杆线虫、海洋益生菌、致病菌之间的相互作用机制。本研究结果将为研究、开发新型海洋益生菌和有效利用海洋微生物资源提供理论和实验依据。

过度使用抗生素所引起的副作用和细菌的耐药性对人类和养殖动物的健康构成了严重威胁。益生菌作为抗生素治疗的潜在替代品在人类健康和动物及渔业养殖中发挥着越来越重要的作用。海洋中丰富的尚未被利用的微生物资源成为开发新益生菌的重要来源。本项目包括以下内容，（1）通过建立秀丽隐杆线虫抗金黄色葡萄球菌的筛选模型，从野生牡蛎等海洋生物肠道中分离的海洋细菌中，筛选出了一株对秀丽隐杆线虫具有保护效果的海洋益生菌。在该研究中采用荧光定量PCR方法，发现这株海洋益生菌通过上调秀丽隐杆线虫体内MAPK信号通路和抗菌肽相关的基因的表达量起到了保护线虫抵抗金黄色葡萄球菌的作用机理。（2）通过秀丽隐杆线虫抗鳗弧菌的筛选模型，从海洋生物肠道中分离的海洋细菌中，筛选出了一株对秀丽隐杆线虫具有保护效果的海洋益生菌。通过转录组测序分析发现此益生菌是通过刺激线虫分泌、调控抗菌效应物以及解毒蛋白来抑制鳗弧菌的感染从而发挥其保护线虫的作用机制。（3）完成了2株海洋新菌的多相分类工作。菌株PX7T分离自威海小石岛沉积物，属于红杆菌科、滨海杆菌属的新物种，命名为海洋滨海杆菌（Primorskyibacter marinus）。菌株H1304 T分离于威海沿岸的海鲶鱼肠道，属于粘杆菌科，粘杆菌属的新物种，命名为海鲶鱼芹菜同型杆菌（Cohaesibacter celericrescens）。