BIochemical and Molecular Genetics on the Components of Respiratory Chain of Bacteria as a Juvenile Periodontal Pathogen.

点击翻译按钮获取中文摘要

Acti no bacillus actinoinycetemcomitans is one of the etiological pathogens in juvenile periodontitis. This organism can grow in the aerobic atmosphere or anaerobic conditions. In general, aerobic organism uses the electrochemical potential produced by aerobic electron transferring system (respiratory chain) as energy for the growth. In this project, I studied the respiratory components of A.acuinomycetemcomkans by use of molecular biological and biochemical techniques in order to clarify the physiological role of the respiratory chain. Initially I purified almost to homogeneity the NADH-ubiquinone oxidoreductase (NADH dehydrogenase) and ubiquinol-oxygen oxidoreductase (ubiquinol oxidase). The purified NADH dehydrogenase was composed of homotrimer of single polypeptide with a molecular weight of 47,000, indicating that this enzyme belongs to NDH-1 type dehydrogenase. The ubiquinol oxidase was composed of two subunits with the molecular weights of 50,000 and 29,000. The results of reduced-minus-oxidized difference spectrum and the molecular composition suggest that this oxidase belongs to cytochrome bd type quinol oxidase. I obtained the information for the conserved regions, by alignment of the amino acid sequences of other bacterial bd type oxidases. By PCR methods, we amplified the DNA for the partial region encoding a part of subunit a. The DNA sequence data indicated the high homology to that of Huemophilus influenzae all sequence of which was already published. The determination of complete sequence of nucleotide of the open reading frame is now in progress.We found the unique inhibitors for the respiratory chain of this bacteria. These are tannins which was isolated from plant. The mechanism of the inhibition of these compounds has been studying.