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

革兰氏阳性链球菌和革兰氏阳性菌等微生物 阴性梭菌是一种致病或致病因素 龋齿、牙周炎和牙周病的病因学(S)。 这些细菌的致病性部分取决于它们的能力。 形成各种有机酸和有毒的含硫化合物 作为碳水化合物和氨基酸最终产物的衍生物 发酵。这些代谢产物对人体有潜在的细胞毒性 上皮细胞和其他组织细胞。这项研究计划的目的是 有两个方面：(1)鉴定和表征 构成这些产生能量的途径，以及(2)分离基因 在这些途径中编码特定的代谢特征以用作 用于质粒或转座子介导的基因转移的可选择标记 在梭状杆菌中。为此，我们最近净化了和 梭杆菌两种独特的磷酸葡萄糖苷酶的特性 桑寄生ATCC 25557。正在讨论的酶，麦芽糖6-磷酸 水解酶和磷酸-β-葡萄糖苷酶催化水解酶 化学合成的显色和荧光α-和β- 6-磷酸葡萄糖苷。编码两种酶的基因，Malh和 PBgA，现已被克隆和测序。什么时候 以适当的载体掺入适当的启动子之后， 这些基因非常适合作为水稻的选择标记。 致病菌毒力因子的遗传操作与分析 口腔梭菌。

Microorganisms such as the Gram-positive Streptococci and Gram- negative Fusobacteria are causative or contributory agents in the etiology of dental caries, gingivitis and periodontal disease(s). The pathogenicity of these bacteria resides in part in their capacity to form a variety of organic acids and toxic sulfur-containing derivatives as end-products of carbohydrate and amino acid fermentation. These metabolic products are potentially cytotoxic for epithelial and other tissue cells. The aims of this research program are two-fold: (1) to identify and characterize the enzymes that constitute these energy-yielding pathways, and (2) to isolate genes encoding specific metabolic traits in these pathways for use as selectable markers for plasmid or transposon-mediated gene transfer in Fusobacteria. To this end, we have recently purified and characterized two unique phospho-glucosidases from Fusobacterium mortiferum ATCC 25557. The enzymes in question, maltose 6-phosphate hydrolase and phospho-beta-glucosidase, catalyze the hydrolysis of chemically synthesized chromogenic and fluorogenic alpha- and beta- glucoside 6-phosphates. The genes encoding the two enzymes, malH and pbgA respectively, have now been cloned and sequenced. When incorporated behind suitable promoters in an appropriate vector, these genes will be eminently suitable as selection markers for the genetic manipulation and analysis of virulence factors of pathogenic oral Fusobacteria.