药用昆虫喙尾琵琶甲肠道抗菌活性放线菌的筛选及鉴定

【目的】探究药用昆虫喙尾琵琶甲Blaps rynchopetera肠道具有抗菌活性的放线菌，为抗菌药物开发提供新的放线菌资源。【方法】结合稀释涂布法和选择培养法从喙尾琵琶甲成虫肠道分离放线菌。以耐甲氧西林金黄色葡萄球菌(methieillin-resistant Staphylococus aureus)、金黄色葡萄球菌、大肠杆菌Escherichia coli、粪肠球菌Enterococcus faecalis、鼠伤寒沙门氏菌Salmonella typhimurium 和铜绿假单胞菌Pseudomonas aeruginosa 6株致病细菌以及黑曲霉Aspergillus niger、青霉菌Penicillium expansum和白色念珠菌Canidia albicans 3株致病真菌为指示菌，通过牛津杯琼脂扩散法测试放线菌次生代谢产物的抗菌活性。随后，采用分子生物学方法进行16S rRNA序列分析鉴定活性显著的18株放线菌并构建系统发育树。【结果】从喙尾琵琶甲成虫肠道中分离到176株共生放线菌，初步活性筛选结果显示其中46株放线菌表现出不同程度的抗菌活性。多株放线菌对致病菌具有广谱的抑菌作用且抑菌圈直径超过阳性对照药。选择抑菌圈直径大于15 mm的18株放线菌进行分子鉴定，结果显示均为链霉属Streptomyces。【结论】喙尾琵琶甲肠道含有丰富的抗菌活性放线菌资源。

Screening and identification of actinomycetes with antimicrobial activity from the gut ofthe medicinal insectBlaps rynchopetera(Coleoptera: Tenebrionidae)

【Aim】 In order to provide new actinomycete resources for the development ofantimicrobial drugs, actinomycetes with antimicrobial activity from the gut of Blapsrynchopetera were explored. 【Methods】 Actinomycetes were isolated from the gut of B.rynchopetera adults by using dilution coating method and selective culture method. With sixpathogenic bacteria methieillin-resistant Staphylococus aureus, S. aureus, Escherichiacoli, Enterococcus faecalis, Salmonella typhimurium and Pseudomonas aeruginosa, and threepathomycetes Aspergillus niger, Penicillium expansum and Canidia albicans as the indicatorstrains,the antimicrobial activities of secondary metabolites of actinomycetes were testedby Oxford cup method. Subsequently, 16S rRNA sequence analysis was performed to identifythe 18 strains of actinomycetes with significant activity through molecular biologicalmethod and construct a phylogenetic tree. 【Results】 A total of 176 strains of symbioticactinomycetes were isolated from the gut of B. rynchopetera adults. Preliminaryantimicrobial screening showed that among them 46 actinomycete strains had differentdegrees of antimicrobial activities. Some actinomycetes exhibited broad-spectrumantimicrobial activity, with their inhibition zone diameters larger than those of thepositive control drugs. Eighteen actinomycete strains with the inhibition zone diameterlarger than 15 mm were selected for molecular identification, and the results showed thatthey were Streptomyces spp. 【Conclusion】 There are abundant actinomycete resources withantimicrobial activity in the gut of B. rynchopetera.