Oral bacteria exist as compositionally and structurally complex populations in biofilms colonizing the tissues of the mouth. In most cases, oral biofilms are compatible with health. It is perturbations caused by environmental stresses that induce the changes in the composition and metabolic activities of biofilm bacteria that lead to the initiation and progression of oral diseases. The overall goals of the proposal are to provide detailed molecular and physiologic information about the capacity of oral bacteria to form and persist in biofilms, with particular focus on environmental stresses that can modulate the virulence of oral bacteria and enhance the pathogenic potential of oral biofilms. To achieve these goals, the following aims are outlined:
Aim 1. Analyze the molecular basis for post-transcriptional control of dnaK operon expression and stress tolerance in S. mutans.
Aim 2. Determine the role of (p)ppGpp in physiologic homeostasis, growth and survival decisions, and virulence expression in exponentially-growing S. mutans.
Aim 3. Dissect the molecular basis for stress tolerance and modulation of relP expression by a MarR transcriptional regulator and two ATP binding cassette exporters. By implementing the research plan, we will disclose fundamental details about the intimate linkage of stress tolerance with the ability of this organism to form biofilms on surfaces of the oral cavity. The research will provide the scientific community with an array of information that can be used to develop novel and more effective strategies to prevent and treat oral diseases and other debilitating human infectious diseases.

Public Health Relevance

The bacteria that cause oral diseases must be able to tolerate environmental stresses in the form of low pH, harmful oxygen radicals and deprivation for nutrients. The research conducted here examines the way in which bacteria regulate gene expression in response to their environment to optimize their ability to cause disease. Using state-of- the-art technologies, new targets for therapies to prevent or treat oral diseases and other infections in humans are being identified.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE013239-15
Application #
8471011
Study Section
Oral, Dental and Craniofacial Sciences Study Section (ODCS)
Program Officer
Lunsford, Dwayne
Project Start
1999-09-01
Project End
2015-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
15
Fiscal Year
2013
Total Cost
$330,680
Indirect Cost
$104,960
Name
University of Florida
Department
Dentistry
Type
Schools of Dentistry
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Shields, Robert C; Zeng, Lin; Culp, David J et al. (2018) Genomewide Identification of Essential Genes and Fitness Determinants of Streptococcus mutans UA159. mSphere 3:
Liu, Yuan; Palmer, Sara R; Chang, Hsiaochi et al. (2018) Differential oxidative stress tolerance of Streptococcus mutans isolates affects competition in an ecological mixed-species biofilm model. Environ Microbiol Rep 10:12-22
Burne, R A (2018) Getting to Know ""The Known Unknowns"": Heterogeneity in the Oral Microbiome. Adv Dent Res 29:66-70
Kaspar, Justin; Shields, Robert C; Burne, Robert A (2018) Competence inhibition by the XrpA peptide encoded within the comX gene of Streptococcus mutans. Mol Microbiol 109:345-364
Underhill, Simon A M; Shields, Robert C; Kaspar, Justin R et al. (2018) Intracellular Signaling by the comRS System in Streptococcus mutans Genetic Competence. mSphere 3:
Zeng, Lin; Chen, Lulu; Burne, Robert A (2018) Preferred Hexoses Influence Long-Term Memory in and Induction of Lactose Catabolism by Streptococcus mutans. Appl Environ Microbiol 84:
Son, M; Kaspar, J; Ahn, S J et al. (2018) Threshold regulation and stochasticity from the MecA/ClpCP proteolytic system in Streptococcus mutans competence. Mol Microbiol 110:914-930
De Furio, Matthew; Ahn, Sang Joon; Burne, Robert A et al. (2017) Oxidative Stressors Modify the Response of Streptococcus mutans to Its Competence Signal Peptides. Appl Environ Microbiol 83:
Shields, Robert C; O'Brien, Greg; Maricic, Natalie et al. (2017) Genome-wide screens reveal new gene products that influence genetic competence in Streptococcus mutans. J Bacteriol :
Kaspar, Justin; Underhill, Simon A M; Shields, Robert C et al. (2017) Intercellular communication via the comX-Inducing Peptide (XIP) of Streptococcus mutans. J Bacteriol :

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