Du Lihui, He Xiaoying, Zhang Hong, Liu Fang, Ju Xingrong, Yuan Jian
College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, People's Republic of China.
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, People's Republic of China.
J Food Prot. 2015 Feb;78(2):370-5. doi: 10.4315/0362-028X.JFP-14-294.
Gastrointestinal probiotics are important members of intestinal microflora in both healthy animals and human beings, and these bacteria may reduce the risk of infection caused by certain opportunistic pathogens through exclusive inhibition, competition, and displacement. The lp_1643 protein on the cell surface of Lactobacillus plantarum WCFSI was assumed to possess a mucus-binding capability. This study aimed to determine if purified His-N2 protein exclusively inhibits pathogen adhesion to porcine mucus. The interaction of the His-N2 protein with porcine mucus was determined by indirect enzyme-linked immunosorbent assay (ELISA), and the adhesion was assessed by a traditional plating method to count the bacteria adhered to the porcine mucus. Indirect ELISA showed that His-N2 protein adhered to porcine mucus, and its interacting molecules existed. The His-N2 protein effectively inhibited the adhesion of Escherichia coli DH5α, Listeria monocytogenes CMCC54004, Salmonella Typhimurium ATCC 14028, and Shigella flexneri CMCC(B)51572 to porcine mucus. Results showed that inhibition of pathogen adhesion to porcine mucus depended on dose and strain. The adhesion of L. monocytogenes CMCC54004, Salmonella Typhimurium ATCC 14028, and S. flexneri CMCC(B)51572 was reduced by 95.7, 97.0, and 95.7%, respectively, by pre-adding 100 μl of 3.92 mg/ml of His-N2 protein, whereas that of E. coli DH5α was only 50.4%. The inhibition of adhesion of some pathogens by His-N2 was different at pH 6.6 and 7.5. The inhibition of E. coli DH5α, L. monocytogenes CMCC54004, and Salmonella Typhimurium ATCC 14028 at pH 6.6 was significantly higher than that at pH 7.5, whereas no statistically significant difference was observed in S. flexneri CMCC(B)51572. These results suggest that various types of inhibition mechanisms of His-N2 were involved in different pathogens.
胃肠道益生菌是健康动物和人类肠道微生物群的重要成员，这些细菌可通过排他性抑制、竞争和替代作用降低某些机会性病原体引起感染的风险。植物乳杆菌WCFS1细胞表面的lp_1643蛋白被认为具有黏液结合能力。本研究旨在确定纯化的His-N2蛋白是否能排他性抑制病原体对猪黏液的黏附。通过间接酶联免疫吸附测定（ELISA）确定His-N2蛋白与猪黏液的相互作用，并采用传统平板计数法评估黏附情况，以计数黏附于猪黏液的细菌。间接ELISA表明His-N2蛋白可黏附于猪黏液，且存在相互作用分子。His-N2蛋白有效抑制了大肠杆菌DH5α、单核细胞增生李斯特菌CMCC54004、鼠伤寒沙门氏菌ATCC 14028和宋内志贺氏菌CMCC(B)51572对猪黏液的黏附。结果表明，对病原体黏附猪黏液的抑制作用取决于剂量和菌株。预先添加100 μl 3.92 mg/ml的His-N2蛋白后，单核细胞增生李斯特菌CMCC54004、鼠伤寒沙门氏菌ATCC 14028和宋内志贺氏菌CMCC(B)51572的黏附分别减少了95.7%、97.0%和95.7%，而大肠杆菌DH5α的黏附仅减少了50.4%。His-N2对某些病原体黏附的抑制作用在pH 6.6和7.5时有所不同。在pH 6.6时，His-N2对大肠杆菌DH5α、单核细胞增生李斯特菌CMCC54004和鼠伤寒沙门氏菌ATCC 14028的抑制作用显著高于pH 7.5时，而宋内志贺氏菌CMCC(B)51572未观察到统计学上的显著差异。这些结果表明，His-N2的各种抑制机制参与了对不同病原体的作用。
