微生物农药耳霉菌致病性的PCR检测

Determination of acute toxicity and pathogenicity of microbial pesticide Conidioblous thromboides by PCR

目的 应用PCR扩增技术对微生物农药耳霉菌经口给予大鼠可能引起的感染性和致病性进行评价。方法 将50只健康7~9周龄SPF级Wistar大鼠按体重随机分为两组,分别为对照组10只,实验组40只,雌雄各半。将1.0×108units/ml微生物农药耳霉菌悬浮剂按1.0 ml/只经口一次性灌胃给予大鼠,对照组不做处理;连续观察21 d。记录动物的体重、中毒症状、死亡情况,并对死亡动物进行大体解剖。于染毒后第0、3、7、14、21天分别处死实验组动物各6只,雌雄各半;对照组动物在第21天处死,收集不同时间点和不同组别的动物血液、脑、淋巴结、肝、脾、肺、肾等组织及粪便,提取其中的基因组DNA,进行PCR扩增实验,并对相应脏器进行病理学检测。结果 各组实验动物在实验周期内无明显中毒症状,未见死亡,大体解剖及病理组织检查未见明显异常。染毒后各个时间点所取材各组动物血液及组织中耳霉菌的PCR扩增结果均为阴性。结论 微生物农药耳霉菌经口急性染毒后对实验动物大鼠未见感染性及致病性。

Objective To evaluate the infectivity and pathogenicity of Conidioblous thromboides （C. Thromboides） to rats exposed through gavage by PCR strategy. Methods SPF Wistar rats, 7-9 weeks old,were randomly divided into two groups, the experimental group （n=40,half female and half male） and the control group（n=10,half female and half male）. 1.0xl0s units/ml C. thromboides suspending agent was administrated, 1.0 ml for one rat, through gavage for the experimental group. No treatment was conducted for the control group. The tissue samples, brain, blood, lymph nodes, liver, spleen, lung, kidney and faeces were collected at five different time points from the experimental group,0,3,7, 14,and 21 day after treatment. As for the control group, the specimens were collected only at the 21th day. Histopathological examination and PCR amplification test with nuc- LSU gene specific primers of C. Thromboides were carried out for both groups. Results After administration,the rats were observed for 21 days. No toxic effect and death for all the rats during this period were observed. No pathological changes were found. Also no C. Thromboides was found in all tissue samples in PCR reactions. Conclusion C. thromboides can not be amplificated from all the animal＇s tissues and organs after oral exposure,which suggests that the C. thromboides have no infectivity or pathogenicity to rats.