Proteomics Analysis of Lactobacillus casei Zhang, a New Probiotic Bacterium Isolated from Traditional Home-made Koumiss in Inner Mongolia of China

Abstract

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. Molecular & Cellular

Gene expression profile of probiotic Lactobacillus casei Zhang during the late stage of milk fermentation

“…casei Zhang is a new probiotic strain isolated from homemade koumiss in Inner Mongolia of China (Li, Lu, Guo, Li, & Zhang, 2010;Wang et al, 2008Wang et al, , 2009Wu, Wang, Yu et al, 2009;Zhang et al, 2008;Zhang, Yu, Wu et al, 2010), which has been used as starter in the manufacture of dairy products (Wang, Dong, Chen, Cui, & Zhang, 2010). It has high tolerance to simulated gastric, intestine juices and bile salts, similar to commercial probiotic strain L. casei Shirota ).…”

Starter cultures used in probiotic dairy product preparation and popular probiotic dairy drinks

“…It requires riboflavine, folic acid, Ca pantothenate and niacin for growth. It doesn't form gas and shows strong proteolytic effect after lysis (Kilic, 2008;Ernas & Karagozlu, 2013;Wu et al, 2009). …”

Proteomics in China: Ready for prime time

“…In addition, Chinese proteomists launched a number of other important proteomic investigations on food microbes [139], livestock [140], industry [141], natural medicine [142], and animals [143,144].…”