过量表达purC基因对Lactococcus lactis NZ9000酸胁迫抗性的影响  

Effects on acid-stress tolerance of Lactococcus lactis NZ9000 by overexpressing purC

作　　者：杨佩珊 张娟[1,2] 刘为佳[1,2] 朱政明 堵国成 YANG Peishan;ZHANG Juan;LIU Weijia;ZHU Zhengming;DU Guocheng(Key Laboratory of Industrial Biotechnology,Ministry of Education,Jiangnan University,Wuxi 214122,China;Key Laboratory of Carbohydrate Chemistry and Biotechnology,Ministry of Education,Jiangnan University,Wuxi 214122,China;School of Biotechnology,Jiangnan University,Wuxi 214122,China)

机构地区：[1]工业生物技术教育部重点实验室(江南大学),江苏无锡214122 [2]江南大学生物工程学院,江苏无锡214122 [3]糖化学与生物技术教育部重点实验室(江南大学),江苏无锡214122

出　　处：《食品与发酵工业》2019年第8期8-14,共7页Food and Fermentation Industries

基　　金：国家自然科学基金(31470160);江苏省产学研前瞻性联合研究项目(BY2016022-39)

摘　　要：通过在乳酸乳球菌Lactococcus lactis NZ9000中过量表达嘌呤代谢途径中编码磷酸核糖基氨基咪唑-琥珀酰胺合酶的pur C基因,测定了重组菌株在酸胁迫条件下的存活率,经p H 4. 0胁迫培养4 h后,重组菌株的存活率为对照菌株的83. 2倍。采用ATP测定试剂盒和高效液相色谱分别考察菌株胞内ATP和氨基酸含量。结果表明,重组菌株在酸胁迫条件下维持了更高的胞内ATP和氨基酸(天冬氨酸、苏氨酸、谷氨酸和γ-氨基丁酸)含量,分别通过为细胞提供能量和消耗胞内质子的方式,帮助乳酸乳球菌抵御酸胁迫。研究发现,在乳酸乳球菌中过表达pur C基因能够明显提高菌株的酸胁迫抗性,同时为进一步通过改造嘌呤代谢途径提高乳酸菌酸胁迫耐受性提供了新的思路。In this study,purC encodes the phosphoribosylaminoimidazole-succinocarboxamide synthase in the purine metabolic pathway was overexpressed in Lactococcus lactis NZ9000.After treating the recombinant strain with acidic stress (pH=4.0) for 4 h,its survival rate was 83.2 times higher than that of the control strain.The recombinant strain maintained higher intracellular contents of ATP and amino acids (aspartate,glutamate,threonine,and γ-aminobutyric acid) under acidic stress.Thereby,the acid tolerance of L.lactis was improved by providing energy to cells and consuming intracellular protons.This provides a new idea for further improving the acid-tolerant ability of lactic acid bacteria by altering purine metabolism.

关 键 词：purC过表达 酸胁迫耐受性 LACTOCOCCUS LACTIS NZ9000 

分 类 号：TS201.3[轻工技术与工程—食品科学]