Molecular Genetic Approach for the Virulence Factors in Prevotella

普氏杆菌是牙周病原菌中最常见的一种，然而，它的毒力因素却鲜为人知。本研究的目的是分析普氏杆菌的血凝素、溶血素、氯化血红素结合蛋白和磷酸酶等毒力因子的基因序列及其调控。但由于包涵体的形成，该基因产物不具有血凝素活性。在普氏菌属中没有发现类似的PHG基因序列。报道了从中间假单胞菌27菌株中克隆的血凝素基因。我们报道了在一些有限的中间P.mediaTIGR菌株中发现了该基因，TIGR在中间P.mediate菌株17全基因组测序项目中报道了与产黑素假单胞菌溶血素基因相似的溶血素基因。我已经克隆了这个基因，并表达了溶血活性。在黑色假单胞菌中没有发现类似的测序基因。我们继续研究中间青霉分离株基因核苷酸多态性与同溶活性的关系。我们报道了绿茶儿茶素对几种毒力因子的抑制作用，如普雷沃特氏菌的磷酸酶活性和卟啉单胞菌的牙龈痛活性。我们还报道了与北京首都大学合作开展的中间青霉菌和黑色青霉菌不同流行情况的流行病学研究。

Prevotella is the most frequently isolated among the periodontopathic bacteria, however, it's virulent factors are less known. The aim of present project was to analysis the gene sequence, and its regulation of the hemagglutinin, hemolysin, hemin binding protein and phosphatases as the virulence factors in Prevotella.The hemagglutinin study in P.intermedia was done to try to express of the phg gene in Escherichia coli using the GST fusion protein system. However, the gene product did not show the hemagglutinin activity, because of forming the inclusion body. Similar sequence of the phg gene was not found among Prevotella species.Beem et al. reported that the hemagglutinin gene was cloned from the P.intermedia strain 27. We reported that this gene was found in some limited strains of P.intermediaTIGR(The Institute for Genomic Research) had reported the hemolysin gene similar to the P.melaninogenica hemolysin gene in the P.intermedia strain 17 whole genomic sequencing project. I have cloned this gene, and have expressed the hemolytic activity. Similar sequenced gene was not found in P.nigrescens. I continue to investigate the relation between the nucleotide polymorphisms of gene and the homolytic activity among P.intermedia isolated strains.We reported that the catechins from green tea inhibited several virulence factors, such as the phosphatase activities in Prevotella, and the gingipain activities in Porphyromonas. We also reported the epidemiological research of the different prevalence of the P.intermedia and P.nigrescens, which collaborated with the Beijing Capital University.