Faculty Pages - UF College of Dentistry

Gena Tribble

Oral Biology

Research Assistant Professor
(352) 846-0761
gtribble@dental.ufl.edu

Ph.D., East Carolina University School of Medicine,
    Microbiology and Immunology, 1998

B.S., University of Georgia,
    Microbiology, 1992

Main Interests:

Porphyromonas gingivalis is an oral anaerobe commonly associated with periodontal disease. Chronic infections with this organism are difficult to eradicate using antibiotics or mechanical cleaning methods. This persistence within the sub-gingival crevice is due in part to the ability of these bacteria to invade and survive within gingival epithelial cells. The invasion process is complex, and multiple bacterial virulence factors appear to be involved in entry of the pathogen into host cells. Our goals are to define the molecular events triggered by the bacteria during a successful invasion, and to understand the response of host cells to the presence of internalized bacteria. Using modern molecular and cell biology techniques, we are currently studying the events mediated by a P. gingivalis phosphoserine phosphatase that is secreted during the invasion process. Our work indicates that this enzyme is important for internalization, and also for survival of bacteria in the host cell cytoplasm.

A second area of research in our lab is the transfer of antibiotic resistance genes between members of the oral flora. The transfer of DNA between bacteria is assumed to play an important role in dissemination of antibiotic resistance. Unfortunately, little information is available on the extent of genetic transfer occurring in plaque biofilms. Interspecies genetic exchange can involve the conjugal horizontal transfer of antibiotic resistance genes and other virulence factors, which may contribute to the development of periodontal infections resistant to therapy. We are currently initiating experiments designed to clarify the role of Porphyromonas and Prevotella species in horizontal DNA transfer in the plaque biofilm. These studies center on the identification of mobile tetracycline resistance elements from clinical isolates, and the subsequent capture of these elements for functional and structural analysis.

Our long term goals are to increase our understanding of the interactions of these important pathogens with the host and with other members of the plaque biofilm. The information gained by these studies will be crucial for future attempts to design therapeutic interventions strategies tocontrol P. gingivalis infections.

Publications:

Tribble, G., Ahn, Y.T., Lee, J., Dandekar, T., & Jayaram, M. (2000). DNA recognition, strand selectivity, and cleavage mode during integrase family site-specific recombination. J Biol Chem., 275(29), 22255-67.

Lee, J., Tribble, G., & Jayaram, M. (2000). Resolution of tethered antiparallel and parallel holliday junctions by the Flp site-specific recombinase. J Mol Biol., 296(2), 403-19.

Tribble, G.D., Parker, A.C., & Smith, C.J. (1999). Transposition genes of the Bacteroides mobilizable transposon Tn4555: role of a novel targeting gene. Mol Microbiol., 34(2), 385-94.

Tribble, G.D., Parker, A.C., & Smith, C.J. (1999). Genetic structure and transcriptional analysis of a mobilizable, antibiotic resistance transposon from Bacteroides. Plasmid, 42(1), 1-12.

Smith, C.J., Tribble, G.D., & Bayley, D.P. (1998). Genetic elements of Bacteroides species: a moving story. Plasmid. 40(1), 12-29.

Tribble, G.D., Parker, A.C., & Smith, C.J. (1997). The Bacteroides mobilizable transposon Tn4555 integrates by a site-specific recombination mechanism similar to that of the gram-positive bacterial element Tn916. J Bacteriol., 179(8), 2731-9.