关键词:  喙尾琵琶甲, 肠道放线菌, 抗菌活性, 分子鉴定, 系统发育树

Abstract: 【Aim】 In order to provide new actinomycete resources for the development of antimicrobial drugs, actinomycetes with antimicrobial activity from the gut of Blaps rynchopetera were explored. 【Methods】 Actinomycetes were isolated from the gut of B. rynchopetera adults by using dilution coating method and selective culture method. With six pathogenic bacteria methieillin-resistant Staphylococus aureus, S. aureus, Escherichia coli, Enterococcus faecalis, Salmonella typhimurium and Pseudomonas aeruginosa, and three pathomycetes Aspergillus niger, Penicillium expansum and Canidia albicans as the indicator strains,the antimicrobial activities of secondary metabolites of actinomycetes were tested by Oxford cup method. Subsequently, 16S rRNA sequence analysis was performed to identify the 18 strains of actinomycetes with significant activity through molecular biological method and construct a phylogenetic tree. 【Results】 A total of 176 strains of symbiotic actinomycetes were isolated from the gut of B. rynchopetera adults. Preliminary antimicrobial screening showed that among them 46 actinomycete strains had different degrees of antimicrobial activities. Some actinomycetes exhibited broad-spectrum antimicrobial activity, with their inhibition zone diameters larger than those of the positive control drugs. Eighteen actinomycete strains with the inhibition zone diameter larger than 15 mm were selected for molecular identification, and the results showed that they were Streptomyces spp. 【Conclusion】 There are abundant actinomycete resources with antimicrobial activity in the gut of B. rynchopetera. 

Key words: Blaps rynchopetera, gut actinomycetes, antimicrobial activity, molecular identification, phylogenetic tree