REGULATION OF SUGAR TRANSPORT AND METABOLISM IN LACTIC ACID AND ORAL BACTERIA

微生物是一种致病因子或致病因子。 各种口腔疾病，包括龋齿、牙周炎和 牙周炎。革兰氏阳性链球菌和沙门氏菌的致病性 革兰氏阴性厌氧菌(梭杆菌、细毛菌)可以是 部分归因于有机酸和有毒硫磺的产生 这些物种在饮食糖发酵过程中的衍生物和 氨基酸。这个研究项目的目标有两个。第一， 是对组成这些产能和代谢酶的特征 多阶段路径。第二，界定遗传学和分子生物学 酵母菌发酵途径活性的调控机制 口腔细菌。过去一年的成就包括：[1]、 两个基因的克隆、序列分析及其在大肠杆菌中的表达 新的酶(磷酸-α-和磷酸-β-葡萄糖苷酶) Mortiferum梭杆菌[2]的分类、序列比对和 组成第4族的酶活性部位残基的鉴定 属于糖基水解酶超家族；[3]，特征， 磷酸化α-天冬氨酸基因的定位、克隆和定点突变 葡萄糖苷酶基因(GlvA)对芽孢杆菌基因组的贡献 测序计划，和[4]，独有的化学合成 测定用显色底物和荧光磷化底物 α-和β-磷酸糖基水解酶活性的检测。 编码梭杆菌这些独特酶的基因(MalH和pbgA， 将被分离并整合到合适的载体中。 编码这些“报告”酶的质粒或转座子结构将 被用于操纵和转移遗传信息 口腔致病细菌。

Microorganisms are causative or contributory agents in the etiology of a variety of oral diseases including dental caries, gingivitis, and periodontitis. The pathogenicity of Gram-positive streptococci and of Gram-negative anaerobes (Fusobacteria, Leptotrichia ssp.) can be attributed in part, to the generation of organic acids and toxic sulfur derivatives by these species during fermentation of dietary sugars and amino acids. The goals of this research program are two-fold. The first, is to characterize the enzymes that comprise these energy-yielding and multi-stage pathways. Second, to define the genetic and molecular mechanisms for regulation of the activities of fermentation pathways in oral bacteria. Accomplishments of the past year include : [1] , the cloning, sequence analysis, and expression in Escherichia coli of two novel enzymes (phospho-alpha- and phospho-beta-glucosidase) from Fusobacterium mortiferum; [2], the classification, sequence alignment and identification of active-site residues of enzymes constituting Group 4 of the glycosylhydrolase super-family; [3] , the characterization, mapping, cloning, and site-directed mutagenesis of the phospho-alpha- glucosidase gene (glvA) as a contribution to the Bacillus Genome Sequencing Project, and [4] , the chemical synthesis of unique chromogenic and fluorogenic phosphorylated substrates for the assay and detection of alpha- and beta- phospho-glycosylhydrolase activities. Genes encoding these unique enzymes from Fusobacteria (malH and pbgA , respectively) will be isolated and incorporated into suitable vectors. Plasmid or transposon constructs encoding these "reporter" enzymes will be used for the manipulation, and transfer of genetic information in pathogenic oral bacteria.