The Key Laboratory of Dairy Biotechnology and Bioengineering, Ministry of Education, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, China.
Mol Cell Proteomics. 2009 Oct;8(10):2321-38. doi: 10.1074/mcp.M800483-MCP200. Epub 2009 Jun 8.
Lactobacillus casei Zhang, isolated from traditional home-made koumiss in Inner Mongolia of China, was considered as a new probiotic bacterium by probiotic selection tests. We carried out a proteomics study to identify and characterize proteins expressed by L. casei Zhang in the exponential phase and stationary phase. Cytosolic proteins of the strain cultivated in de Man, Rogosa, and Sharpe broth were resolved by two-dimensional gel electrophoresis using pH 4-7 linear gradients. The number of protein spots quantified from the gels was 487 +/- 21 (exponential phase) and 494 +/- 13 (stationary phase) among which a total of 131 spots were identified by MALDI-TOF/MS and/or MALDI-TOF/TOF according to significant growth phase-related differences or high expression intensity proteins. Accompanied by the cluster of orthologous groups (COG), codon adaptation index (CAI), and GRAVY value analysis, the study provided a very first insight into the profile of protein expression as a reference map of L. casei. Forty-seven spots were also found in the study that showed statistically significant differences between exponential phase and stationary phase. Thirty-three of the spots increased at least 2.5-fold in the stationary phase in comparison with the exponential phase, including 19 protein spots (e.g. Hsp20, DnaK, GroEL, LuxS, pyruvate kinase, and GalU) whose intensity up-shifted above 3.0-fold. Transcriptional profiles were conducted to confirm several important differentially expressed proteins by using real time quantitative PCR. The analysis suggests that the differentially expressed proteins were mainly categorized as stress response proteins and key components of central and intermediary metabolism, indicating that these proteins might play a potential important role for the adaptation to the surroundings, especially the accumulation of lactic acid in the course of growth, and the physiological processes in bacteria cell.
从中国内蒙古传统家庭自制马奶酒中分离出的干酪乳杆菌 Zhang 经过益生菌选择试验被认为是一种新的益生菌细菌。我们进行了一项蛋白质组学研究，以鉴定和描述 L. casei Zhang 在指数期和静止期表达的蛋白质。使用 pH 4-7 线性梯度通过二维凝胶电泳分离在德曼、罗高萨和夏普肉汤中培养的菌株的细胞质蛋白。从凝胶中定量的蛋白质斑点数量为 487 +/- 21（指数期）和 494 +/- 13（静止期），其中总共 131 个斑点通过 MALDI-TOF/MS 和/或 MALDI-TOF/TOF 根据显著的生长阶段相关差异或高表达强度蛋白进行鉴定。通过同源簇（COG）、密码子适应指数（CAI）和 GRAVY 值分析，该研究提供了 L. casei 蛋白质表达图谱的初步见解。在研究中还发现了 47 个在指数期和静止期之间显示出统计学显著差异的斑点。与指数期相比，静止期有 33 个斑点至少增加了 2.5 倍，其中包括 19 个蛋白质斑点（如 Hsp20、DnaK、GroEL、LuxS、丙酮酸激酶和 GalU），其强度增加了 3.0 倍以上。通过实时定量 PCR 转录谱证实了几个重要差异表达蛋白。分析表明，差异表达蛋白主要分为应激反应蛋白和中心和中间代谢的关键成分，表明这些蛋白可能在适应环境方面发挥潜在的重要作用，特别是在生长过程中乳酸的积累和细菌细胞的生理过程。
