双歧杆菌细菌素bifidocin A对大肠杆菌细胞总蛋白表达的影响

为从蛋白表达水平探讨细菌素bifidocin A对革兰氏阴性菌（G－）的抑菌作用机理，利用双向凝胶电泳（two-dimensional electrophoresis，2-DE）联合蛋白质基质辅助激光解析电离-飞行时间质谱（matrix assisted laser analytical ionization time-of-flight mass spectrometry，MALDI-TOF MS）技术分析细菌素bifidocin A处理前后G－大肠杆菌1.90细胞总蛋白表达差异情况，并在基因本体论注释基础上，对差异表达蛋白进行功能分类及富集分析。研究结果表明，经细菌素bifidocin A处理后，大肠杆菌（Escherichia coli）CGMCC1.90共有12 个差异蛋白点，其中2 个蛋白表达上调，10 个蛋白表达下调；MALDI-TOF MS共鉴定得到10?个差异表达蛋白，主要涉及细胞膜组成、能量代谢以及应激反应等方面。这些结果揭示细菌素bifidocin?A可能是通过改变细胞膜结构、阻断三羧酸循环、减少能量和三磷酸腺苷提供以及降低细胞对外界胁迫条件的抵抗能力等达到对大肠杆菌的抑菌效果。

Influence of Bifidocin A on the Expression of Whole Cell Proteins in Escherichia coli

Bifidocin A, a novel bacteriocin with antimicrobial activity against a wide range of foodborne bacteria produced by Bifidobacterium animalis BB04, has a potential application as biopreservative in the food industry. The objective of this study was to investigate the antibacterial mechanism of action of bifidocin A against Gram-negative strain based on the level of protein expression. The difference in the expression level of total cell proteins in Escherichia coli CGMCC1.90 before and after treatment with bifidocin A was analyzed by using two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Functional classification and enrichment analysis of differentially expressed proteins were carried out based on gene ontology annotation analysis. Results showed that a total of 12 differentially expressed protein spots were found after treatment with bifidocin A, two of which were upregulated and ten of which were downregulated. Ten differentially expressed proteins were identified by MALDI-TOF, which were mainly involved in cell membrane composition, energy metabolism and stress response. These results suggested that bifidocin A might inhibit the growth of E. coli by altering the cell membrane structure, blocking the tricarboxylic acid cycle, reducing the availability of energy and adenosine triphosphate (ATP) and decreasing the resistance of the cells to external stress conditions.