-
摘要：本研究以荧光假单胞菌和蜡样芽孢杆菌为指示菌，研究了植物乳杆菌产细菌素JL-A65对这两种指示菌的抑菌机制。先通过分别添加1×MIC、2×MIC、3×MIC细菌素JL-A65作用于两种指示菌，发现荧光假单胞菌分别在8h、7h、5h进入衰亡期，蜡样芽孢杆菌分别在5h、5h、4h左右开始受抑制，证明细菌素JL-A65对两种指示菌都能发挥抑菌作用，且在一定浓度范围内，抑菌作用的强弱与细菌素JL-A65的浓度呈正相关。后通过在指示菌生长的1h、2h、3h、4h、5h添加细菌素JL-A65，发现1h、2h、3h添加细菌素两种菌都几乎无法生长，4h、5h添加细菌素则能很快使处于对数生长期的菌体转为衰亡期，证明在一定时间范围内，越早添加细菌素JL-A65，其抑菌效果就越好。流式细胞仪检测细菌素JL-A65处理后两种指示菌细胞壁膜的完整性，发现荧光假单胞菌反应2h后细胞膜破坏程度超过92%、蜡样芽孢杆菌则在反应0.5h后细胞膜破坏程度就超过94%，说明细菌素JL-A65对蜡样芽孢杆菌膜的破坏性强于对荧光假单胞菌。检测两种菌液上清液的电导率并计算电解质相对渗透率，发现反应3h后荧光假单胞菌和蜡样芽孢杆菌的电解质相对渗透率分别达82.76%和90.91%；同时检测OD260nm/280nm，发现在反应的3h内两种菌液上清液的OD260nm/280nm都呈现上升趋势，这都说明细菌素JL-A65作用下两菌膜的完整性被破坏，胞内物质外流。最后比较了不同浓度庆大霉素对两种指示菌的抑菌效果与细菌素JL-A65的差异，发现对荧光假单胞菌的抑菌效果细菌素JL-A65更优，对蜡样芽孢杆菌的抑菌效果庆大霉素更强。25981
- 上一篇：新型N-糖酰胺酶PNGase Stca的克隆表达与特性研究
- 下一篇：超声超高压以及高压均质技术对肌原纤维蛋白热诱导凝胶特性及分子特性的影响
毕业论文关键词：细菌素JL-A65；植物乳杆菌；抑菌机制；荧光假单胞菌；蜡样芽孢杆菌
The Antibacterial Mechanism of Bacteriocins JL-A65 Produced by Lactobacillus plantarum
Abstract： In this study, Pseudomonas fluorescens and Bacillus cereus as the indicators of bacteria, the study of Lactobacillus plantarum bacteriocin is on these two indicators of bacteria's antibacterial mechanism. 1×MIC, 2×MIC and 3×MIC bacteriocin JL-A65 were applied to the two kinds of indicator bacteria respectively. It was found that Pseudomonas fluorescens entered the decay stage at 8h, 7h and 5h respectively, and the bacteria were at 5h, 5h and 4h began to be inhibited, proved that the bacteriocin JL-A65 can play a bacteriostatic effect on both indicator bacteria, and within a certain concentration range, the bacteriostatic effect is positively correlated with the concentration of bacteriocin JL-A65. After adding 1h, 2h, 3h, 4h, 5h for the growth of the indicated bacteria, we found that the two kinds of bacteria added at 1h, 2h and 3h were almost unable to grow. At 4h and 5h, and soon to make the logarithmic growth phase of the bacteria to decline, proved that within a certain period of time, the earlier addition of bacteriocin JL-A65, the better the antibacterial effect. Flow cytometry was used to detect the integrity of the cell wall of the two strains after treatment with the bacteriocin JL-A65. It was found that the cell membrane destruction rate was more than 92% after 2h of Pseudomonas fluorescens reaction, and the cell membrane was damaged after 0.5h reaction. The degree of more than 94%, indicating that the bacteriocin JL-A65 on the Bacillus cereus membrane more destructive than the Pseudomonas fluorescens. The relative permeability of the electrolyte of Pseudomonas fluorescens and Bacillus cereus was 82.76% and 90.91%, respectively. It was found that the OD260nm / 280nm of the two supernatants showed an increasing trend within 3 hours after the reaction, which indicated that the integrity of the two bacterial membranes under the action of bacteriocin JL-A65 was destroyed and the intracellular matter was outflowed. Finally, we compared the bacteriostatic effect of gentamicin on the two kinds of indicator bacteria and the difference of bacteriocin JL-A65. It was found that the antibacterial effect of bacteriocins JL-A65 to Pseudomonas fluorescens was better than that to Bacillus cereus, and the antibacterail effect of gentamicin to Bacillus cereus is stronger than that to Pseudomonas fluorescens.