School of Arts, Sciences & Business
- University of Texas Health Science Center Houston; Houston, TX
- Ph.D., Microbiology and Molecular Genetics
Dental caries remains one of the most widespread oral diseases disproportionately affecting low-income children, the working poor and elderly. Despite advances in non-invasive management, traditional surgical approaches by dentists continue to be practiced as the predominant method of treatment at great economic and biological cost. This collaborative project looks to develop a non-invasive method of caries management, the goal being to rapidly and non-invasively kill microflora on the tooth surface inherent to caries.
- Determine the power density/exposure time required for high lethality of acid-producing microflora in ex vivo and artificial caries
Bacteria that maintain a flexible survival strategy are thought to have a distinct advantage over those that are more limited. This current research project focuses on understanding how genetic exchange contributes to bacterial fitness during infection and biofilm formation.
One possible explanation for this adaptability is the hypothesis that bacteria can access different virulence allele types from neighboring strains, dramatically increasing their genetic repertoire. This variability might provide modification and/or additional pathways and functions that are not essential for bacterial growth but overall confer a selective advantage in a particular environment.
Although all bacteria are able to diversify their genomes by random mutagenesis, species that can also transfer DNA between strains have an added advantage in their ability to re-assort useful mutations into the same bacterial cell. Porphyromonas gingivalis is a Gram-negative anaerobe that colonizes plaque biofilms in the human gingival crevice, and is a causative agent in the development of chronic and severe periodontal disease.
In order to test these ideas, my research has focused on understanding how P. gingivalisstrains swap different fimbrial allele types as an adaptive virulence strategy, providing the best overall ability to survive and cause disease. Understanding how these opportunistic bacteria shift from commensal to pathogenic in the host environment will prove pivotal in combating these resourceful organisms in the future.
- Determining some of the basic molecular mechanisms and possible environmental cues responsible for triggering virulence gene exchange
- Understanding biofilm competition/cooperation/viability in same species and multi-species biofilms
Professional Affiliations & Memberships
- American Society for Microbiology (ASM)
- American Association of Dental Research (AADR)
- International Association of Dental Research (IADR)
- Kerr JE, Abramian JR, Dao DHV, Rigney TW, Fritz J, Pham T, Gay I, Parthsarathey, Wang BY, Zhang WJ, Tribble GD. Genetic Exchange of Fimbrial Alleles Exemplifies the Adaptive Virulence Strategy of Porphyromonas gingivalis. PLOS ONE. In Press 2014.
- Tribble GD, Kerr JE and, Wang BY. Genetic Diversity in the Oral PathogenPorphyromonas gingivalis: Molecular Mechanisms and Biological Consequences. Future Microbiology. May 2013. 8:5, 607-620.
- Tribble GD, Rigney TW, Dao DH, Wong CT, Kerr JE, Taylor BE, Pacha S, Kaplan HB. 2012. Natural competence is a major mechanism for horizontal DNA transfer in the oral pathogen Porphyromonas gingivalis. MBio. 2012 Jan 31;3(1).
- Banta LM, Kerr JE, Cascales E, Giuliano, M, Bailey M, Mckay C, Chandran V, Waksman G, and Christie PJ. 2011.An Agrobacterium VirB10 Mutation Conferring a Type IV Secretion Gating Defect. J Bact. 2011 May;193(10):2566-74.
- Raivio T: "This study significantly advances our understanding of early events in the assembly and functioning of..." of: [Kerr JE, Christie PJ. Evidence for VirB4-mediated dislocation of membrane-integrated VirB2 pilin during biogenesis of the Agrobacterium VirB/VirD4 type IV secretion system. J Bacteriol. 2010 Oct; 192(19):4923-34; Faculty of 1000, 10 Nov 2010. FFa=8- Must Read
- Kerr JE and Christie PJ. 2010. Evidence for VirB4-mediated dislocation of membrane-integrated VirB2 pilin during biogenesis of the Agrobacterium VirB/VirD4 type IV secretion system. J. Bact. Oct;192(19):4923-34.
- Kerr JE*, Jakubowski SJ*, Garza I, Krishnamoorthy V, Bayliss R, Waksman G, Christie PJ. 2009. Agrobacterium VirB10 domain requirements for type IV secretion and T pilus biogenesis. Mol Microbiol. 71(3):779-94.
- Microbiology (BIO 340)
- General Microbiology (BIO 253)
- Genetics and Genomics for the Clinical Practitioner (BIO 260)
- Immunology (BIO 403)
- Senior Seminar (BIO 451)