Li Jie, Aroutcheva Alla A, Faro Sebastian, Chikindas Michael L
Rutgers, The State University of New Jersey, New Brunswick, NJ 08901-8520, USA.
Infect Dis Obstet Gynecol. 2005 Sep;13(3):135-40. doi: 10.1080/10647440500148156.
To determine the mechanism of antimicrobial action of lactocin 160, a bacteriocin produced by the healthy vaginal strain of Lactobacillus rhamnosus, using an established model, with Micrococcus luteus ATCC 10420 as a test organism.
Sensitivity of M. luteus to lactocin 160 was determined by the diffusion assay. Loss of cellular ATP in the lactocin-treated cells was elucidated using a commercially available ATP determination kit (luciferin-luciferase bioluminescence assay). Luminescence intensity as a reflection of ATP quantity was determined using a luminometer. Dissipation of membrane potential (Deltapsi) was studied using fluorophore DiSC3(5) with the fluorescence spectrum sensitive to changes in Deltapsi.
Lactocin 160 inhibited growth of M. luteus ATCC 10420 at a concentration of 5 microg/ml. There were no significant changes in the intracellular ATP level of M. luteus upon the addition of 20 microg/ml of lactocin 160. However, the extracellular ATP level increased significantly. This means that the treatment of cells with lactocin 160 resulted in an efflux of ATP from inside the cells. Therefore, a partially purified lactocin 160 preparation (16 microg /ml of the bacteriocin in the sample) killed sensitive cells and dissipated 3.12 +/- 0.36% of Deltapsi.
Lactocin 160 has a mode of action typical for bacteriocins. It disturbs the cellular membrane (Deltapsi dissipation) and induces ATP efflux, most likely because of the pore formation, which is a common mechanism of action for many bacteriocins.
使用已建立的模型，以藤黄微球菌ATCC 10420作为测试菌株，确定由健康阴道鼠李糖乳杆菌菌株产生的细菌素——乳杆菌素160的抗菌作用机制。
通过扩散试验确定藤黄微球菌对乳杆菌素160的敏感性。使用市售的ATP测定试剂盒（荧光素 - 荧光素酶生物发光测定法）阐明经乳杆菌素处理的细胞中细胞ATP的损失情况。使用发光计测定作为ATP量反映的发光强度。使用对膜电位变化敏感的荧光团DiSC3(5)研究膜电位（ΔΨ）的耗散情况。
乳杆菌素160在浓度为5微克/毫升时抑制藤黄微球菌ATCC 10420的生长。添加20微克/毫升的乳杆菌素160后，藤黄微球菌的细胞内ATP水平没有显著变化。然而，细胞外ATP水平显著增加。这意味着用乳杆菌素160处理细胞导致ATP从细胞内流出。因此，部分纯化的乳杆菌素160制剂（样品中细菌素浓度为16微克/毫升）杀死敏感细胞并使膜电位耗散3.12±0.36%。
乳杆菌素160具有典型的细菌素作用模式。它扰乱细胞膜（膜电位耗散）并诱导ATP流出，最可能是由于孔形成，这是许多细菌素常见的作用机制。
