Genco C A
Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA.
Adv Dent Res. 1995 Feb;9(1):41-7. doi: 10.1177/08959374950090010801.
As with other pathogens, a requirement for the in vivo growth of Porphyromonas gingivalis is that the organism must be capable of obtaining iron from the host. The ability to utilize hemin and hemin-containing compounds for nutritional iron has been documented for several pathogenic bacteria, including P. gingivalis; however, the mechanisms involved in hemin uptake are poorly defined. I have determined that P. gingivalis transports the entire hemin moiety into the cell by an energy-dependent mechanism and that the binding and accumulation of hemin are induced by growth of cultures in the presence of hemin. A model of hemin transport in P. gingivalis consistent with these results is presented. I have also found that, in P. gingivalis, hemin regulates the expression of several putative virulence factors; this in turn results in the increased virulence potential of P. gingivalis as assessed in an animal model. Regulation of hemin-responsive genes in P. gingivalis may occur by a negative regulator, as has been described in other pathogenic organisms.
与其他病原体一样，牙龈卟啉单胞菌在体内生长的一个必要条件是该微生物必须能够从宿主获取铁。包括牙龈卟啉单胞菌在内的几种病原菌已被证明具有利用血红素及含血红素化合物获取营养性铁的能力；然而，血红素摄取所涉及的机制却鲜有明确阐述。我已确定牙龈卟啉单胞菌通过一种能量依赖机制将完整的血红素部分转运到细胞内，并且血红素的结合和积累是由培养物在血红素存在下生长所诱导的。本文提出了一个与这些结果相符的牙龈卟啉单胞菌血红素转运模型。我还发现，在牙龈卟啉单胞菌中，血红素调节几种假定毒力因子的表达；在动物模型中评估时，这反过来又导致牙龈卟啉单胞菌的毒力潜能增加。牙龈卟啉单胞菌中血红素反应基因的调节可能如其他致病生物中所描述的那样，由一个负调节因子介导。
