云南干热地区地衣放线菌新结构次级代谢产物及其生物活性的研究

Actinomycetes are important sources for discovery of new drug lead compounds. Lichen is a special composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi in a symbiotic relationship. The lichen-associated actinomycetes showed biodiversity and potential ability to produce bioactive substances. Up to now, the bioactive compounds derived from the lichen-associated actinomycetes are only few reported in abroad. Especially, the anti-influenza virus compounds have not been obtained from lichen-associated actinomycetes till now. Our laboratory had obtained rich actinomycete resources from various lichens in dry-hot region of Yunnan Province. In the following work, we have performed the anti-influenza virus and antimicrobial activity screening, as well as chemical screening and genetic screening of secondary metabolites synthase. Five potential new species of strains showed high bioactivity and ability to produce rich secondary metabolites. Among them, two genus have not been reported on secondary metabolites yet. Five new compounds had been preliminarily obtained from fermentation broth of three strains. Based on the above results, the project will comprehensively study the bioactive secondary motabolites of these five strains by OSMAC strategy, isolate and identify the chemical constituents from the fermentation products of the strains, and test the anti-influenza virus and antimicrobial activities of the compounds. The project is aim to discover new bioactive compounds from lichen-associated actinomycetes, so as to provide chemical substance basis for discoving microbial drug lead compounds. The research will excavate potential medicinal resouces from lichen-associated actinomycetes, and broaden new sources and new pathway for seeking new natural bioactive substances from actinomycetes.

放线菌是发现新药先导化合物的重要来源。地衣是菌藻复合共生形成的特殊生物类群，与地衣共生的放线菌具有生物多样性和产生生物活性物质的潜能。至今来源于地衣放线菌的活性化合物仅在国外有少量文献报道，尤其是抗流感病毒的活性物质尚未从地衣放线菌获得过。本实验室从云南干热地区的地衣中分离获得了种类丰富的放线菌，进行了抗流感病毒和抗菌活性筛选、化学筛选及次生代谢产物合成酶基因筛选，获得了5株活性高、代谢产物丰富、基因筛选阳性的潜在新物种，其中2个属未见代谢产物方面的研究报道，已从其中3株菌的发酵产物中初步获得了5个新化合物。本项目拟采用OSMAC策略开展5株放线菌的活性次生代谢产物研究，分离鉴定菌株发酵产物的化学成分，检测其生物活性，旨在发现结构新颖的抗流感病毒和抗菌活性化合物，为微生物药物先导化合物的发现提供化学物质基础，从地衣放线菌中挖掘潜在的药用新资源，为寻找放线菌新天然活性物质拓宽新来源和新途经。

与地衣共生的放线菌具有生物多样性和产生物活性物质的潜能。目前关于地衣放线菌活性代谢产物的研究报道相对较少。在前期已从云南干热地区地衣放线菌中筛选获得具有抗菌和抗流感病毒活性菌株的基础上，本项目利用OSMAC策略完成了7株地衣放线菌系统的次生代谢产物研究，对菌株进行了放大发酵以及发酵产物的提取分离和结构鉴定，共分离鉴定了82个化合物，其中18个为新化合物，2个为新天然产物，4个为首次从微生物资源中获得，拓宽了活性化合物的天然来源途径。对部分化合物进行了生物活性检测，其中14个化合物显示抗菌活性，5个化合物显示抗H1N1流感病毒的活性，3个化合物显示抗氧化活性。对其中两株拟无枝酸菌进行了基因组测序，经antiSMASH分析，分别存在烯二炔类和利福霉素类化合物的生物合成基因簇，进一步确定了相关的调控基因，并获得过表达菌株，活性优于原始菌株，后续研究正在开展。通过项目实施，已发表SCI期刊论文10篇，获得国内发明专利授权2项，共培养博士研究生2名和硕士研究生8名，其中5名硕士生已毕业。本项目的研究结果为微生物药物先导化合物的发现提供了化学物质基础，获得了具有药用潜力的地衣放线菌资源，为寻找放线菌新天然活性物质拓宽了新的来源和途经。