Prevention, Diagnosis and Treatment of Periodontal Disease Based on Genetic Analysis of Periodontopathogens.

牙龈卟啉单胞菌（拟杆菌）的毒力因子如菌毛、血凝素和外膜蛋白已被研究其功能和基因。将编码菌毛主要亚基蛋白（fimbrilin）的fimA基因的上游和下游区域克隆到pUC质粒和特异性表达载体中。通过使用噬菌体T7 RNA聚合酶/启动子表达载体系统鉴定了由下游区域编码的分子量为50和80千道尔顿的蛋白质。这两种蛋白质似乎与菌毛作为次要成分的基础上通过Western印迹分析获得的结果。一个血凝素定位于整个包膜的这种生物体被纯化的均匀形式。纯化的血凝素具有巯基蛋白酶活性，正如我们所推测的。将编码该双功能材料的基因的N-末端部分克隆到pUC 19中。我们正试图克隆该基因的C末端部分，并对整个基因进行测序，以估计该物质的一级结构。编码该生物体的主要免疫显性表面蛋白（7 - 5 K蛋白）的基因已被克隆。基因的DNA测序正在进行中，工作已进入收尾阶段。

Virulence factors such as fimbriae, hemagglutinin and an outer membrane protein from porphyromonas (Bacteroides) gingivalis have been studied as to their functions and genes. Downstream and upstream regions from the fimA gene which encodes a major subunit protein (fimbrilin) of fimbriae were cloned in pUC plasmids and a specific expression vector. Proteins with molecular masses of 50- and 80-kilodaltone, encoded by the downstream region were identified by using the bacteriophage T7 RNA polymerase/promoter expression vector system. The two proteins seemed to be associated with fimbriae as minor components based upon the results obtained by Western blot analysis. A hemagglutinin localized in whole envelope of this organism was purified in a homogeneous form. The purified hemagglutinin possessed a thiol protease activity as we have speculated. An N-terminal portion of the gene encoding this bifunctional material was cloned in pUC19. We are trying to clone a C-terminal portion of the gene and to sequence the entire gene in order to estimate the primary structure of this material. The gene encoding a major immunodominant surface protein (the 7 5K protein) of this organism has been cloned. DNA sequencing of the gene is in progress and the work is in the finishing touch.