棉铃虫人工饲料主要污染细菌鉴定及其抗生素筛选

Identification of Main Contaminated Bacteria of Cotton Bollworm Artificial Feed and Screening of Antibiotics

棉铃虫的人工饲养是对其进行昆虫病原菌生物测定的重要步骤,而饲料污染是影响棉铃虫培养成功率的主要因素。因此,选择合适的抗生素对棉铃虫的饲养具有重要意义。为明确棉铃虫饲料中污染细菌的组成,筛选可抑制污染菌的抗生素,本研究以受污染棉铃虫饲料中分离出的9个菌株为实验材料,观察菌株形态。采用16S rDNA系统发育分析法构建进化树,同时根据药敏与生理生化实验,确定分离菌株的生理生化特性。结果表明,9个菌株共呈现5种生理生化特性,其中,2株与肠球菌属(Enterococcus sp.)接近,2株与埃希氏菌属(Escherichia sp.)接近,2株与志贺氏菌属(Shigella sp.)接近,2株与肠杆菌属(Enterobacter sp.)接近,1株与沙雷氏菌属(Sarratia sp.)接近。抗生素筛选实验结果显示,卡那霉素对于不同菌株的抑菌效果最好。这为提高棉铃虫人工饲养成活率具有重要意义。

Artificial rearing of Helicoverpa armigera is an important step in the bioassay of insect pathogens,and the feed contamination is the main factor for its cultivation.Therefore,the selection of appropriate antibiotics is crucial to the rearing of Helicoverpa armigera.In order to determine the composition of contaminated bacteria in the feed of Helicoverpa armigera,and screen antibiotics which can inhibit the contaminated bacteria,we used 9 strains isolated from polluted xylophilus feed as experimental materials to observe the morphology of the strains.The phylogenetic tree was constructed by 16 S rDNA phylogenetic analysis,and the physiological and biochemical characteristics of the isolated strains were determined according to drug sensitivity and physiological and biochemical experiments.The results showed that 9 strains showed 5 physiological and biochemical characteristics.Among them,two were close to Enterococcus sp.,two were close to Escherichia sp.,two were close to Shigella sp.,two were close to Enterobacter sp.,and one was close to Sarratia sp..The results of antibiotic screening showed that kanamycin had the best bacteriostatic effect on different strains.This research provided a significance to improve the survival rate of the artificial rearing for Helicoverpa armigera.