摘要：食品中亚硝酸钠超标一直是人们关注的问题。因此，探索降解亚硝酸盐的方法显得尤为重要。本课题首先证明了植物乳杆菌具有在亚硝酸盐这一对自身具有毒性的环境下，生存的能力，并且可以对其进行降解。鉴定本实验室中分离的植物乳杆菌Lactobacillus plantarum。并且通过设计引物系统，使用PCR法获得疑似亚硝酸盐还原酶片段，割胶回收进行3730常规测序。Real-time PCR来检测mRNA转录表达水平，发现第一小时glnR的转录表达的水平，相对提高1.39倍。glnR是氮代谢全局调控者，推断出glnR对于亚硝酸还原酶基因来说，对于整个亚硝酸盐胁迫下差异转录表达的来说，是作为激活者，进行正反馈的调节作用。在第二小时，疑似亚硝酸盐还原酶基因ORD的转录表达量相对于整体转录水平上升了1.73倍。在第三小时，相关未知基因HP相对于整体的转录表达水平下调了1.80倍。验证了ORD基因存在一定为亚硝酸盐还原酶的可能性，并且猜想ORD与HP是乳酸菌应对亚硝酸盐胁迫环境的调控过程中的关键基因。并且初步检测判明疑似nir基因HP的启动子序列。24215
毕业论文关键词：亚硝酸盐还原酶；Lactobacillus plantarum；PCR法；glnR；启动子
Analysis of lactobacillus nitriate reductase encoding gene
Abstract：People has concerned about the excessive nitrite for a long time .Therefore, developing new method for degradation of nitrite is particularly important. This topic first proved the lactobacillus plantarum with nitrite that is toxic environments to them,can survive, and it can on the reduce it.The lactobacillus plantarum that was separated in this laboratory,was identify as Lactobacillus plantarum WCFS1.And amplify the uncertain fragment of nir gene ,by the special PCR primer system,then,sequencing after gel extraction by Roche 3730.Real - time PCR to detect the expression of mRNA transcription level, find the first hour glnR transcriptional expression levels, relative increased by 1.39 times. GlnR is one of global regulators for nitrogen metabolism.So the result can deduce glnR for nitrite reductase gene, for the differences of transcriptional expression under nitrite stress, is being activated regultor, carries on the positive feedback adjustment.In the second hour, transcriptional expression of uncertain nitrite reductase gene relative to the overall transcription level rose by 1.73 times.In the third hour, unknown gene_HP expression level relative to the overall transcription by 1.80 times.To verify the possibility of that ORD is nitrite reductase gene, and guess HP and ORD is the key gene of regulation under nitrite stress.And detect the promotor of uncertain nir gene HP.
Key Words：nitrite reductase；Lactobacillus plantarum WCFS1；PCR system；glnR；promotor
目录
第一部分 绪论 1
第一章 文献综述 1
1.1乳酸菌中亚硝酸还原酶研究进展 1
1.2 检测nir基因的PCR法 2
1.3 氮代谢的调控研究进展 2
1.4 原核生物的识别方法 3
1.4.1 基于结构特征进行的细菌启动子识别 4
1.4.3 计算机建模方法进行的细菌启动子识别 5
1.4.4 利用RNA 聚合酶的特殊亚基进行细菌启动子的预测 6
2.1 本课题的研究目的和意义 7
2.2 本课题研究的主要内容 7
第二部分 研究论文 8
第一章 生长特性与降解能力的研究 8
1.1 实验材料与试剂 8
1.1.1实验菌种： 8
1.1.2实验试剂 8
1.1.3培养基 9
1.1.4实验设备 9
1.2 实验方法 9 乳酸菌亚硝酸盐还原酶相关基因的研究:http://www.youerw.com/shengwu/lunwen_17616.html