Molecular analysis of pathogen in periodontopathic bacteria

成人牙周炎是一种感染性疾病，可导致牙齿脱落。它会导致咀嚼困难，最终导致牙周病患者的生活质量下降。由于已经进行了许多尝试来阐明疾病的病原体，因此对这些病原体发挥其作用的分子机制知之甚少。为了阐明牙周致病菌的致病机制，我们对伴放线放线杆菌（A.actinomycetemcomitans）、邻苯二甲酸二异辛酯杆菌（Bacteriodeschidius）和齿垢密螺旋体（Treponema denticola）的致病基因进行了分析，并确定了伴放线杆菌菌毛基因（fap）在其定植过程中的作用。该微生物的有菌毛的菌株在固体培养基上传代时失去菌毛。W发现fap基因的表达在无菌毛的菌株中降低（Microbiol.帕托格已知蛋白酶对宿主组织发挥细胞毒性作用。我们测定了一个蛋白酶基因（prH）的序列， 关于我们 这是很难得到足够的生长在合成培养基的表征。蛋白酶的分子量为47，873，PrtH具有溶血活性（Imfect. Immun. 1997，65：4888-4891）。一些报道指出，系统性化疗失败是由于口腔中的幽门螺杆菌定植造成的。我们评价了口腔微生物与幽门螺杆菌之间的拮抗作用。幽门螺杆菌与牙龈卟啉单胞菌和F. nucreatum共聚集。另一方面，几种口腔细菌抑制幽门螺杆菌的生长（FEMS Microbial. Lett. 1997，152：355-361）。使用野生型菌株和单基因缺陷突变体评价致病性是评价其致病性的最有效方式。我们构建了一个敲除突变体的脯氨酰-苯丙氨酸特异性蛋白酶（牙本质素）在齿垢毛癣菌和其特点的突变体。突变株表面疏水性显著降低，形成脓肿的能力下降。此外，我们发现牙本质蛋白与外鞘蛋白的组织化有关。这些结果表明，牙本质素直接对宿主组织发挥细胞毒性作用（J.Bacteriol. 1998，180：3837-38449）。少

Adult periodontitis was Infectious disease and it induce tooth loss. It cause a mastication problem and finally induce poor quality of life in patients with periodontal disease. As many attempts to clarify pathogen of the disease have been performed, the molecular mechanisms by which these pathogens exert their effects are poorly understood. To clarify the pathogenic mechanism of potential periodontopathic bacteria, we tried to characterize genes encoding pathogens from Actionbacillus actinomycetemcomitans, Bacteriodesforsydius and Treponema denticola.We determined the fimbriae gene (fap) of A.actinomycetemcomitans to characterize its role in colonization. The fimbriated strain of this microorganism lost fimbriae upon passaging onto solid medium. W found that expression of the fap gene was decreased in non-fimbriated strain (Microbiol. Pathog. 1997, 23 : 63-69).Proteases were known to exert a cytotoxic effects to host tissue. We detennined the sequence of a protease gene (prH) of B.for … More sythus which is difficult to get enough growth in synthetic medium for a characterization. A molecular mass of the protease is 47,873 and the PrtH possessed hemolytic activity (Imfect. Immun. 1997, 65 : 4888-4891).Several reports indicated the systemic chemotherapy failure was caused by colonization of Helicobcterpylori in oral cavity. We evaluated the antagonistic effects between oral microorganism and H.pylon. H.pylon was coaggregated with P.gingivalis and F.nucreatum. On the other hand, several oral bacteria inhibits growth of H.pylon (FEMS Microbial. Lett. 1997, 152 : 355-361).Evaluation of a pathogenicity using wild type strain and single gene deficient mutant is the most effective way to evaluate its pathogenicity. We constructed a knockout mutant of the prolyl-phenylalanine specific protease (dentilisin) in T denticola and characterized the mutant. Surface hydrophobicity of this microorganism decreased dramatically and ability of abscess formation decreased in the mutant. In addition, we found that dentilisin is associated with organization of outer sheath protein. These results indicated that dentilisin exert a cytotoxic effects to host tissue directly (J.Bacteriol. 1998, 180 : 3837-38449). Less