As an experienced and well trained scientist in the molecular genetics and biochemistry of microbial diseases, I have focused my research program on oral bacterial pathogens important to periodontal diseases. My postdoctoral studies conducted (1990-1995) with Dr. Francis Macrina at the Medical College of Virginia, Virginia Commonwealth University examined the biochemistry and molecular genetics of virulence factors in Porphyromonas gingivalis and the molecular genetics of antibiotic resistance in Bacteroides. My pioneering work on genetic tool development for Porphyromonas lead to the first demonstration of the role of proteases in the virulence of P. gingivalis. Furthermore the genetic tool (an ermF/ermAM antibiotic resistance cassette) is the most widely used in genetics studies in P. gingivalis. My research program has provided evidence for posttranslational regulation of proteolytic activity in P. gingivalis and the first report of the identification of a gingipain proenzyme from this organism. We have also provided evidence of a new paradigm for DNA repair of 8-oxo-7,8-dihydroguanine lesions in P. gingivalis in addition to the first demonstration that gingipains from P. gingivalis can induce caspase-independent apoptosis in endothelial cells. Our work with the P. gingivalis vimA (virulence modulation A) gene, identified in our laboratory, is emerging as a founding member of novel post-translational control mechanism in Gram-negatives. We have begun other studies with Fillifactor alocis, a new emerging Gram-positive bacterium that is now proposed to be a diagnostic indicator of periodontal disease. We were the first to report on the virulence potential of this organism.
Current research projects include:
Studies of the biochemistry and molecular genetics of virulence regulation in Porphyromonas gingivalis.
Studies on the mechanism(s) of Porphyromonas gingivalis-induced in apoptosis.
Studies on the mechanism(s) of oxidative stress resistance in Porphyromonas gingivalis.
Studies on the role of extracytoplasmic function sigma factors on adaptation and virulence regulation in Porphyromonas gingivalis.
Studies on the mechanism(s) of nitric oxide stress resistance in Porphyromonas gingivalis.
Studies on the role of sialization in the pathogenicity of Porphyromonas gingivalis.
Studies on the molecular pathogenic mechanism(s) of Filifactor alocis .