摘要

从健康百岁老人粪便中分离得到双歧杆菌A，一种由双歧杆菌BB04产生的新型广谱细菌素。为了解双歧杆菌A对革兰氏阴性菌的抗菌作用机理，以最小抑菌浓度对大肠杆菌细胞形态、胞内组织、膜透性、膜完整性和膜质子动力（PMF）的影响进行了研究。对OLI 1.90进行了研究。扫描和透射电子显微镜分析表明，双歧杆菌A诱导大肠杆菌细胞的形态和胞内组织的改变。细胞内的组织更易受双歧杆菌A诱导的形态变化的影响。双歧杆菌A引起的K+和无机磷酸盐的泄漏，ATP和UV吸收材料的释放，以及在大肠杆菌细胞中的跨膜电位和pH梯度的崩溃。共聚焦激光扫描显微镜图像显示，用双歧杆菌A处理的大肠杆菌细胞获得碘化丙啶。这些结果表明，双歧杆菌A对大肠杆菌的作用机制涉及细胞质膜的PMF的消散、膜通透性的增加、细胞膜中的孔形成、膜完整性的改变和完整的细胞解体。

Bifidocin A, a novel broad-spectrum bacteriocin produced by Bifidobacterium animalis BB04, was isolated from the feces of a healthy centenarian. To understand the mechanism of the antibacterial action of bifidocin A against gram-negative bacteria, its effects at a minimum inhibitory concentration on cell morphology, intracellular organization, membrane permeability, membrane integrity, and membrane proton motive force (PMF) of Escherichia coli 1.90 were investigated. Scanning and transmission electron microscopy analyses showed that bifidocin A induced alterations in the morphology and intracellular organization of E. coli cells. The intracellular organization was more susceptible to changes induced by bifidocin A than the morphology. Bifidocin A treatment caused the leakage of K+ and inorganic phosphate, the release of ATP and UV-absorbing materials, and a collapse of the transmembrane electrical potential and pH gradient in E. coli cells. Confocal laser scanning microscopy images showed that E. coli cells treated with bifidocin A took up propidium iodide. These results suggested that the mechanism of action bifidocin A against E. coliinvolved dissipation of the PMF of the cytoplasmic membrane, an increase in membrane permeability, pore formation in the cell membrane, a change in membrane integrity, and complete cell disintegration.

https://www.sciencedirect.com/science/article/pii/S0956713515302553