基于蛋白表达分析的干酪乳杆菌ATCC393交互胁迫保护机制

为考察干酪乳杆菌典型株ATCC393在交互胁迫环境下的生理应答机制，应用二维电泳和iTRAQ技术在蛋白水平上比较了交互胁迫前后干酪乳杆菌蛋白质组的变化情况。在对不同处理条件下细胞全蛋白的二维电泳分析中发现，干酪乳杆菌的主要蛋白分布在等电点pI4～7的范围，经酸预适应处理后细胞的蛋白表达产生了较大的变化。通过iTRAQ技术对细胞在酸适应前后以及相应致死条件下蛋白表达的定性及相对定量分析得知，酸诱导所产生的热胁迫应激蛋白（dnaK，dnaJ等）、氧胁迫应激蛋白（mutS，YeaO）以及与代谢相关的酶类上调可能是提高细胞对交互胁迫耐受能力的主要原因，而酸适应后GTP环化水解酶I和GMP合成酶的高表达可能与这一过程的诱导有关。上述研究结果为提高工业生产菌株在发酵生产及加工过程中对外界不利环境的抵御能力，进而通过调控与微生物生理应答机制密切相关的功能元器件实现生产菌株的性能强化提供了重要的生物信息和可借鉴的研究思路。

Protective mechanism of Lactobacillus casei ATCC393 against multiple stresses by proteomics analysis

To investigate the physiological response of Lactobacillus casei ATCC 393 under cross stresses, the two- dimensional gel electrophoresis and the iTRAQ technology were used to analyze the proteome changes before and after the cross-stress treatment. It is found that the main proteins of Lactobacillus casei ATCC393 distribute in the range of PI 4-7, and great changes take place after the acid pre-adaption. Based on the iTRAQ analysis before and after acid pre-adaption as well as the related lethal treatments, the up-regulation of acid-induced heat stress shock proteins （dan K, dna J）, oxidative stress shock proteins （mutS, rec O） and some metabolic enzymes were confirmed to be the key factors to improve the multi-stress resistance of cells. Moreover, the high expression of GrIp cyclohydrolase I and GMP synthase after acid pre-adaptation may be related to the resistance of industrial strains against provides a novel way to enhance the induction of this process. Results in this study will help to improve the stress serious environments during the fermentation and processing. Furthermore, it also performance of industrial strains by regulating certain functional components with renewed biology information.