Ecological Studies on Food-Bacteria from Food and Environments

(1)为了建立一种快速、特异性检测肠出血性大肠杆菌o157: H7的方法，制备了两种小鼠单克隆抗体（MCA）。用流式细胞术（FCM）检测这两种单克隆抗体（1D9和3E8）的特异性。3E8和1D9与大肠杆菌O157: H7、弗氏柠檬酸杆菌和沙门氏菌群N （O: 30）均有反应，但与伯曼大肠杆菌无反应。在含有大肠杆菌O157: H7和大肠杆菌O6: Hl的混合物中，MCA的FCM出现两个不同的峰，而与兔多克隆抗血清的FCM出现一个单峰。根据这些发现，MCA的FCM被认为是一种快速、特异性和有用的方法来检测和鉴定食品成分中的大肠杆菌O157: H7菌株（参考文献#1）。(2)采用荧光标记抗肠毒素抗体的FCM法，建立了一种快速、特异、简便的产气荚膜梭菌孢子表面肠毒素（CPE）检测方法。结果表明，FCM能特异性检测短时间暴露于产气荚膜菌孢子上的CPE。因此，FCM是一种快速、特异、方便的检测C产气荚膜菌孢子上暴露的CPE的方法，有望用于C产气荚膜菌引起的食物中毒的诊断（Ref.#2）。(3)建立了夹心酶联免疫吸附法（ELISA），以*单克隆*抗体和*多克隆*抗体分别作为*捕获*抗体和*检测*抗体，定量测定产气荚膜原肠毒素（CPE）。在0.5 ng/ml-8.0 ?范围内，405 nm处吸光度与纯化CPE浓度呈剂量依赖性关系。克/毫升。夹心ELISA可检测培养物中粗CPE和10%粪便提取物中的CPE。该方法简便、快速、灵敏，可用于GPE的特异性检测（Ref#3）。

(1) To develop a rapid and specific method to detect and/or identify enterohemorrhagic Escberichia coli O 157 : H7, two mouse monoclonal antibodies (MCA) were prepared. Specificities of these two MAbs (1D9 and 3E8) were determined by flow cytometry method (FCM). 3E8 and 1D9 were found to react with E.coli O157 : H7, Citrobacter freundii and Salmonella group N (O : 30), but not with E bermannii With a mixture containing strains of E coil O157 : H7 and E coli O6 : Hl, two different peaks appeared in FCM with MCA, whereas a single peak appeared with polyclonal rabbit antiserum. From these findings, FCM with MCA is suggested to be a rapid, specific, and useful method to detect and identify strain(s) of E celi O157 : H7 in food ingredients (Ref.#1).(2) FCM with fluorescent-labeled anti-CPE antibody was applied to develop a rapid, specific, and convenient method to detect enterotoxin (CPE) exposed on the surface of spores of Clostridium perfringens. The results obtained indicate that FCM can specifically detect CPE exposed on C perfringens spores for a short time. Thus, FCM is found to be a rapid, specific, and convenient assay method for detection of CPE exposed on C perfringens spores, suggesting that it will be hopefully useful to diagnose food poisoning caused by C perfringens (Ref.#2).(3) Sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the quantitative estimation of C perfringens enterotoxin (CPE) using* monoclonal* and* polyclonal* antibodies* as* capturing* and* detecting* antibodies* respectively.* The dose- dependent relationship between absorbance at 405 nm and concentration of purified CPE was obtained over the range of 0.5 ng/ml-8.0 ? g/ml. The sandwich ELISA is found to detect crude CPE in culture and CPE in 10% fecal extracts. This method is a convenient, rapid and sensitive for specific detection of GPE(Ref#3).