基因astE调控微生物抵御丁醇胁迫的生理机制解析  

Physiological Mechanism of the Regulation of Gene ast E on Regulating Microorganism against Butanol Stress in Escherichia coli

作　　者：郭媛[1] 陈燕[1] 林丽华[1] 汤宏赤 毕德武 庞浩[1] 

机构地区：[1]广西科学院非粮生物质酶解国家重点实验室国家非粮生物质能源工程技术研究中心,广西生物炼制重点实验室,南宁530007

出　　处：《基因组学与应用生物学》2017年第1期239-245,共7页Genomics and Applied Biology

基　　金：国家自然科学基金项目(21366007);广西自然科学基金项目(2015GXNSFBA139048,2015GXNSFBA13-9084cb-p C,2014GXNSFBA118129,2014GXNSFAA118078);广西科技攻关项目桂科重(1598004-3,14122004-5);广西科学院基本科研业务费(15YJ22SW05,13YJ22SW02)共同资助

摘　　要：探究敲除精氨酸代谢途径关键酶ast E对大肠杆菌抵御丁醇胁迫能力的影响。借助氨基酸分析仪全面分析ast E基因敲除对细胞内外游离氨基酸水平的变化。同时,通过测定ast E缺失突变株抵御丁醇和酸胁迫的能力,并分析两者之间的联系。研究表明:与对照菌株BW25113相比,突变株△ast E抵御丁醇胁迫和酸胁迫的能力显著提高,分别提高了30%(8 g/L丁醇)和54.5%(p H 3.0)。同时,通过胞内外氨基酸分析发现,高浓度丁醇胁迫可抑制BW25113和△ast E合成谷氨酸的能力,使其浓度分别降低73.6%和89.1%。在此基础上,外源添加精氨酸实验表明:适量精氨酸能有效提高细胞抵御高浓度丁醇胁迫的能力。敲除精氨酸代谢途径关键酶ast E可显著提高大肠杆菌抵御丁醇胁迫的能力,且其调控机制与耐酸胁迫密切相关。This study aimed to investigate the effect of knocking-out astE on protecting cells against butanol stress was investigated. Amino acid analyzer was applied to comprehensively analyze the levels of the free amino acid in strains BW25113 and AastE. Meanwhile, the ability ofastE mutant to resist butanol and acid stress was measured and the relationship between them was analyzed. The physiological and biochemical characteristics ofE. coli were also determined against butanol and acid stresses. Compared to strain BW25113, the cells tolerance of mutant AastE was enhanced for butanol and acid stresses, making cell growth increased by 30% （8 g/L of butanol） and 54.5% （pH 3.0）, respectively, but the high level of butanol could significantly inhibit the synthesis of glutamic acid, making its concentration decreased by 73.6% and 89.1%, respectively. Based on the above result, the experiment of adding exogenous arginine was performed, and we found that adding a moderate amount of arginine could effectively improve cells against the high-concentration butanol stress. Therefore, knocking-out astE can effectively enhance the cell tolerance for butanol stress, in which the physiological mechanism is closely related to acid stress.

关 键 词：astE基因 大肠杆菌 精氨酸 丁醇胁迫 酸胁迫 

分 类 号：Q93[生物学—微生物学]