McDougall L A, Holzapfel W H, Schillinger U, Feely D E, Rupnow J H
Food Science and Technology Department, University of Nebraska, Lincoln 68583-0919.
Int J Food Microbiol. 1994 Dec;24(1-2):295-308. doi: 10.1016/0168-1605(94)90127-9.
A bacteriocin, lactococcin D53, from Lactococcus lactis strain D53 was partially purified by precipitation with ammonium sulfate and dialysis against deionized water, at which time it precipitated from solution. A native molecular weight was determined by gel filtration, where bacteriocin was detected in two fractions which were measured at 104 and 6.7 kDa. A molecular weight of 7.0 kDa under denaturing conditions was determined by Tricine-SDS-polyacrylamide gel electrophoresis. The molecular weight determinations implied that lactococcin D53 complexed with other macromolecules in its native state in solution. Scanning electron micrographs of Lactobacillus D17 target cells treated with lactococcin D53 showed considerable differences from untreated control cells. The bacteriocin-treated cells had rougher, more granular-looking outer surfaces than untreated cells, which appeared smooth. Counts of viable cells in buffer solution rapidly declined by about one log in target cells treated with bacteriocin.
从乳酸乳球菌D53菌株中分离得到的一种细菌素——乳酸乳球菌素D53，通过硫酸铵沉淀和去离子水透析进行部分纯化，此时它从溶液中沉淀出来。通过凝胶过滤测定其天然分子量，在两个组分中检测到细菌素，分子量分别为104 kDa和6.7 kDa。通过Tricine-SDS-聚丙烯酰胺凝胶电泳测定变性条件下的分子量为7.0 kDa。分子量测定表明，乳酸乳球菌素D53在溶液中的天然状态下与其他大分子复合。用乳酸乳球菌素D53处理的德氏乳杆菌D17靶细胞的扫描电子显微镜照片显示，与未处理的对照细胞有很大差异。经细菌素处理的细胞比未处理的细胞具有更粗糙、颗粒感更强的外表面，未处理的细胞表面看起来很光滑。在用细菌素处理的靶细胞中，缓冲溶液中活细胞的数量迅速下降了约一个对数级。
