Verheul A, Russell N J, Van'T Hof R, Rombouts F M, Abee T
Department of Food Science, Agricultural University Wageningen, The Netherlands.
Appl Environ Microbiol. 1997 Sep;63(9):3451-7. doi: 10.1128/aem.63.9.3451-3457.1997.
A nisin-resistant (NISr) variant of Listeria monocytogenes Scott A was isolated by stepwise exposure to increasing concentrations of nisin in brain heart infusion (BHI) broth. The NISr strain was about 12 times more resistant to nisin than was the wild-type (WT) strain. Accordingly, higher nisin concentrations were required to dissipate both components of the proton motive force in the NISr strain than in the WT strain. Comparison of the membrane fatty acyl composition of the sensitive strain with that of its NISr derivative revealed no significant differences. From phospholipid head group composition analysis and phospholipid biosynthesis measurements during growth in the absence and presence of nisin, it could be inferred that the NISr strain produces relatively more phosphatidylglycerol (PG) and less diphosphatidylglycerol (DPG) than the parent strain does. Monolayer studies with pure lipid extracts from both strains showed that nisin interacted more efficiently with lipids derived from the WT strain than with those derived from the NISr strain, reflecting qualitative differences in nisin sensitivity. Involvement of the cell wall in acquisition of nisin resistance was excluded, since the WT and NISr strains showed a comparable sensitivity to lysozyme. Recently, it has been demonstrated that nisin penetrates more deeply into lipid monolayers of DPG than those of other lipids including PG, phosphatidylcholine, phosphatidylethanolamine, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol (R.A. Demel, T. Peelen, R.J. Siezen, B. de Kruijff, and O.P. Kuipers, Eur. J.Biochem. 235:267-274, 1996). Collectively, the mechanism of nisin resistance in this L. monocytogenes NISr strain is attributed to a reduction in the DPG content of the cytoplasmic membrane.
通过在脑心浸液（BHI）肉汤中逐步暴露于浓度递增的乳链菌肽，分离出了产单核细胞李斯特菌Scott A的耐乳链菌肽（NISr）变体。该NISr菌株对乳链菌肽的抗性约为野生型（WT）菌株的12倍。因此，与WT菌株相比，需要更高浓度的乳链菌肽才能消除NISr菌株中质子动力的两个组成部分。敏感菌株与其NISr衍生物的膜脂肪酰基组成比较未发现显著差异。从磷脂头部基团组成分析以及在有无乳链菌肽存在的情况下生长期间的磷脂生物合成测量结果可以推断，与亲本菌株相比，NISr菌株产生的磷脂酰甘油（PG）相对较多，而二磷脂酰甘油（DPG）相对较少。对两种菌株的纯脂质提取物进行的单层研究表明，乳链菌肽与WT菌株来源的脂质的相互作用比与NISr菌株来源的脂质更有效，这反映了乳链菌肽敏感性的质量差异。细胞壁参与耐乳链菌肽的获得被排除，因为WT和NISr菌株对溶菌酶表现出相当的敏感性。最近，已经证明乳链菌肽比其他脂质（包括PG、磷脂酰胆碱、磷脂酰乙醇胺、单半乳糖基二酰基甘油和二半乳糖基二酰基甘油）更深入地渗透到DPG的脂质单层中（R.A. Demel、T. Peelen、R.J. Siezen、B. de Kruijff和O.P. Kuipers，《欧洲生物化学杂志》235:267 - 274，1996）。总体而言，这种产单核细胞李斯特菌NISr菌株的耐乳链菌肽机制归因于细胞质膜中DPG含量的降低。
