Abo-Amer Aly E
Department of Botany, Division of Microbiology, Faculty of Science, Sohag University, Sohag, Egypt.
Acta Microbiol Immunol Hung. 2007 Jun;54(2):107-19. doi: 10.1556/AMicr.54.2007.2.2.
Approximately 63 strains of Lactobacillus acidophilus were isolated from Egyptian home-made cheese and examined for production of antagonism. Only eight strains demonstrated inhibitory activity against spoilage microorganisms (i.e. Staphylococcus aureus and Bacillus cereus) and pathogens (i.e. E. coli, Salmonella sp. and Shigella sp.). Lactobacillus acidophilus AA11 produced higher antimicrobial activity with a wide range of inhibition. The agent AA11 was sensitive to proteolytic enzymes and retained full activity after 30 min at 100 degrees C. Activity against sensitive cells was bactericidal but not bacteriolytic. The compound was produced during growth phase and could be extracted from the culture supernatant fluids with n-butanol. 12% SDS-PAGE analysis of 40% ammonium sulphate precipitated agent showed two peptides with molecular weights of approximately 36 kDa and approximately 29 kDa. No plasmid was identified in Lactobacillus acidophilus AA11 indicating that the genes encoding the inhibitory agent were located on the chromosome. These characteristics identify the inhibitory substance as a bacteriocin, designated acidocin AA11 and confer the agent an application potential as a biopreservative.
从埃及自制奶酪中分离出约63株嗜酸乳杆菌，并检测其拮抗活性。只有8株对腐败微生物（即金黄色葡萄球菌和蜡样芽孢杆菌）和病原体（即大肠杆菌、沙门氏菌属和志贺氏菌属）表现出抑制活性。嗜酸乳杆菌AA11产生的抗菌活性更高，具有广泛的抑制范围。AA11对蛋白水解酶敏感，在100℃下30分钟后仍保留全部活性。对敏感细胞的活性是杀菌性的而非溶菌性的。该化合物在生长阶段产生，可用正丁醇从培养上清液中提取。对40%硫酸铵沉淀剂进行的12%十二烷基硫酸钠聚丙烯酰胺凝胶电泳分析显示出两条分子量约为36 kDa和约29 kDa的肽段。在嗜酸乳杆菌AA11中未鉴定出质粒，这表明编码抑制剂的基因位于染色体上。这些特性将该抑制物质鉴定为一种细菌素，命名为嗜酸乳杆菌素AA11，并赋予该物质作为生物防腐剂的应用潜力。
