DMDC联合Nisin对模拟果汁中肠膜状明串珠菌细胞膜功能的影响

Effect of Dimethyl Dicarbonate Combined with Nisin on Cell Membrane Functions of Leuconostoc mesenteroides in Model Juice

摘要:

本文研究了二甲基二碳酸盐（DMDC）和Nisin处理对模拟果汁中肠膜状明串珠菌的杀菌效果及其细胞膜功能的影响。结果表明：DMDC联合Nisin作用于该菌时的部分杀菌浓度指数为0.38，小于0.50，两者之间具有很好的协同杀菌作用。扫描电镜分析发现该菌经DMDC和Nisin处理后其细胞形态没有发生明显变化。该菌经DMDC处理后仅有个别菌体细胞的膜通透性出现增加，而该菌经Nisin处理后，约7%菌体细胞的膜通透性增加。Nisin处理虽能改变该菌的细胞膜通透性，增加胞外极性物质的摄入，但并不能明显促进胞内物质的流失，高浓度的DMDC处理能导致该菌溶液的紫外吸收值增加约60%。DMDC和Nisin两者对该菌细胞内物质的流失、细胞膜的通透性的增加和胞内pH的下降没有相互促进作用，但DMDC和Nisin的联合作用能促进该菌细胞内脱氢酶的进一步失活。

Abstract:

The effects of dimethyl dicarbonate (DMDC) and nisin treatment on the inactivation of Leuconostoc mesenteroides present in model juice and cell membrane functions were investigated. Combined treatment with DMDC and nisin had a fractional bactericidal concentration index of 0.38 (<0.5) against L. mesenteroides, indicating a strong synergistic bactericidal effect of DMDC and nisin. Scanning electron microscopy analysis showed no obvious changes in the cell morphology of L. mesenteroides treated with these antibacterial agents. Treatment with nisin alone increased the membrane permeability of approximately 7% of the cell population; this effect was stronger than that of treatment with DMDC alone. Despite this effect on membrane permeability and the resultant increase in the cellular uptake of extracellular polar substances, nisin treatment could not significantly reduce the loss of intracellular substances. The ultraviolet absorption value of L. mesenteroides cell suspension increased by approximately 60% after treatment with high concentrations of DMDC. To summarize, DMDC and nisin exhibited a synergistic effect on the inactivation of dehydrogenase activity in L. mesenteroides, but not on membrane permeability, loss of intracellular substances, and alteration of intracellular pH.