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

该计划的主要目标是了解分子 基础，以及微生物在病原学中的作用， 口腔疾病的发病机制。 微生物产品 代谢，包括有机酸和含硫 化合物，要么是致病或促成剂， 龋齿、牙龈炎和牙周炎的发展。 因此，我们的研究工作涉及 阐明生物化学、酶和遗传因素， 负责糖和氨基酸的口服发酵 微生物的 过去一年的主要成就 包括以下步骤： 1. 一种新的磷酸烯醇化酶依赖性的鉴定 麦芽糖：磷酸转移酶系统。 2. 纯化所需的两种酶的同质性， 乳酸菌对糖的代谢。 果糖激酶Ⅱ 催化ATP依赖的 果糖磷酸化，而 磷酸丙糖异构酶是一种关键酶， 用于发酵 通过Embden-Meyerhof-Parnas（糖酵解）途径分解糖。 3. 定点突变有助于鉴定 底物结合和N5- （羧乙基）鸟氨酸合酶。 4. β-胱硫醚酶已被纯化，克隆和测序， 禽波氏杆菌 这种毒素的生物化学基础 （含磷酸吡哆醛）蛋白对成骨细胞的作用 确立了习 定点诱变实验 提供了赖氨酰残基K214参与 辅因子结合，以及半胱氨酸残基在 催化过程 5. 从B制备抗β-胱硫醚酶的抗体。鸟 已用于筛选相同（或相关）的酶， 包括梭杆菌和拟杆菌的口腔病原体的提取物 物种 该研究项目的成果已发表在peer- 评论期刊，也在教科书中讨论过 关于糖运输管理的一章， 乳酸菌的代谢。

The primary goal(s) of this program are to understand the molecular basis, and the roles of microorganisms in the etiology and pathogenesis of oral diseases. The products of microbial metabolism, including organic acids and sulfur-containing compounds, are either causative or contributory agents to the development of dental caries, gingivitis and periodontitis. Consequently, our research efforts are concerned with the elucidation of the biochemical, enzymatic, and genetic factors, responsible for the fermentation of sugars and amino acids by oral microorganisms. Major accomplishments during the past year include: 1. The identification of a novel phosphoenolpyruvate-dependent maltose:phosphotransferase system in Fusobacterium mortiferum. 2. The purification to homogeneity of two enzymes required for the metabolism of sugars by lactic acid bacteria. Fructokinase II catalyzes the ATP-dependent phosphorylation of fructose, whereas triosephosphate isomerase is a key enzyme for the fermentation of sugars via the Embden-Meyerhof-Parnas (glycolytic) pathway. 3. Site-directed mutagenesis has facilitated identification of substrate binding and catalytically functional residues in N5- (carboxyethyl)ornithine synthase. 4. Beta-Cystathionase has been purified, cloned and sequenced from Bordetella avium. The biochemical basis for the toxicity of this (pyridoxal-phosphate containing) protein toward osteogenic cells has been established. Site-directed mutagenesis experiments have provided evidence for participation of the lysyl residue K214 in co-factor binding, and for the role(s) of cysteine residues in the catalytic process. 5. Antibodies prepared against Beta-cystathionase from B. avium have been used to screen for the same (or, related) enzyme(s) in extracts of oral pathogens including Fusobacteria and Bacteroides species. Results from this research program have been published in peer- reviewed Journals, and have also been discussed in a textbook chapter dealing with the regulation of sugar transport and metabolism by lactic acid bacteria.