瑞士乳杆菌发酵乳血管紧张素转化酶抑制活性相关功能基因的研究

本课题依托内蒙古农业大学乳酸菌菌种资源库保藏的775株Lactobacillus helveticus为研究对象，以前期MLST分析结果和菌株蛋白水解活性、发酵乳ACE抑制活性以及Val-Pro-Pro、I1e-Pro-Pro含量为基础，选取表型和基因型差异菌株，采用三代测序方法，结合菌株表型特征，通过比较基因组分析具有不同ACE抑制活性菌株在基因组水平的差异，从细胞壁结合蛋白酶、肽酶和运输系统等基因编码区、非编码区、基因调控区以及DNA甲基化等多方面对Lactobacillus helveticus不同分离株ACE抑制活性进行全面系统的研究，从基因组水平揭示Lactobacillus helveticus发酵乳产ACE抑制肽的分子机理，从而为具有抗高血压特性乳酸菌资源的挖掘及其功能性乳制品开发奠定理论基础。

This project utilizes the resources of 775 Lactobacillus helveticus strains contained in the Lactic Acid Bacteria Collection at the Inner Mongolia Agricultural University. Based on our previous studies by MLST and the analyses of ACE-inhibitory activity, Val-Pro-Pro and Ile-Pro-Pro peptide concentrations produced by these bacteria during milk fermentation, 108 representative sequence types will be selected for re-sequencing analysis. We further aim to integrate the third generation sequencing technology to construct the methylomes of 10 to 20 Lactobacillus helveticus strains. The obtained data will elucidate the strain-specific variation in the ACE-inhibitory capacity attributed to the gene regulator, upstream promoter region, and non-coding nucleotide region. These data interactively reveal the molecular regulatory mechanism of ACE-inhibitory peptide synthesis during milk fermentation. This study strengthens both the theoretical and application basis for future exploitation and development of antihypertensive lactic acid bacterial resources and their related dairy products.