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Molecular mechanism of the reuterin-producing pathway in lactobacilli

乳酸杆菌产生罗伊氏菌素途径的分子机制

基本信息

批准号：
15580241
负责人：
MORITA Hidetoshi
金额：
$ 1.47万
依托单位：
Azabu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Probiotics are live microorganisms that confer health benefits on the host. A great deal of interest has been focused on some members of lactobacilli and bifidobacteria with regard to their use as probiotics. To elucidate the molecular basis on the probiotic property exhibited by Lactobacillus reuteri, we determined the complete genome sequences of L. reuteri and non-probiotic L. fermentum that is phylogenetically closest to L. reuteri in the Lactobacillus. Comparative analysis of both genomes showed that L. reuteri harbors the unique 48 kb genomic island containing the genes necessary for the biosynthesis of a reactive 3-hydroxypropionaldehyde (reuterin) and vitamin B_<12>, both of which may influence the microflora balance in the gut. These findings suggest the lateral gene transfer was involved in the acquisition of the probiotic property in L. reuteri.As mentioned above, vitamin B_<12>-dependent dehydratase seems a crucial enzyme for the reuterin production in L. reuteri, while it … More is known to be an enzyme that exclusively acts to metabolize 1,2-propanediol but not glycerol in several bacteria such as Salmonella spp. This difference on the substrate selectivity may come from the reason why the degradation of glycerol results in producing reuterin naturally toxic to the bacteria. L. reuteri is resistant to reuterin probably because of the high tolerance of ribonucleotide reductase against reuterin, which allows the accumulation and release of reuterin in and from cells. These mechanisms characterize the glycerol degradation by B_<12>-dependent dehydratase encoded by gupCDE and the subsequent reuterin production correlating with the probiotic property in L. reuteri. Furthermore, vitamin B_<12> is produced in L. reuteri, which may have a nutrient effect to host cells and the capability of controlling balance of microflora in gut as well as reuterin. In conclusion, L. reuteri has evolved to a probiotic lactic acid bacterium through lateral transfer of the probiotic gene sets into the genome. Less

益生菌是赋予宿主健康益处的活微生物。乳酸杆菌和双歧杆菌的一些成员作为益生菌的用途引起了人们的极大兴趣。为了阐明罗伊氏乳杆菌益生特性的分子基础，我们测定了罗伊氏乳杆菌的全基因组序列。reuteri和非益生菌L.在遗传学上最接近L.罗伊氏乳杆菌。对两个基因组的比较分析表明，L。罗伊氏菌具有独特的48 kb基因组岛，该基因组岛含有活性3-羟基丙醛（罗伊氏蛋白）和维生素B的生物合成所必需的基因<12>，这两者都可以影响肠道中的微生物群落平衡。这些结果表明，基因的侧向转移参与了乳酸菌益生特性的获得。如前所述，维生素B_<12>依赖性琥珀酸酶似乎是L. reuteri产生罗伊素的关键酶。罗伊，虽然它 ...更多信息已知是一种在沙门氏菌等多种细菌中专门代谢1，2-丙二醇而不代谢甘油的酶。这种底物选择性的差异可能来自于甘油降解导致产生对细菌天然有毒的罗伊素的原因。L.罗伊氏菌对罗伊蛋白具有抗性，可能是因为核糖核苷酸还原酶对罗伊蛋白具有高耐受性，这使得罗伊蛋白在细胞中积累和从细胞中释放。这些机制表征了<12>由gupCDE编码的B_依赖性甘油酶降解甘油以及随后与乳酸杆菌中的益生特性相关的罗伊氏蛋白的产生。reuteri。此外，维生素B<12>_在L. reuteri，其可能对宿主细胞具有营养作用，并具有控制肠道微生物群落平衡的能力以及reuterin。综上所述，L.通过将益生菌基因组侧向转移到基因组中，罗伊氏菌已进化为益生菌乳酸菌。少