Justin R. Kaspar, PhD

Assistant Professor

University of Florida, 2016, Microbiology/Immunology


Dr. Justin Kaspar was born in Bay City, Texas and grew up in Blessing, Texas within Matagorda County. Dr. Kaspar attended Texas A&M University and received a B.S. in Microbiology while receiving training in bacteriology and bacteriophage biology while volunteering in Dr. Ryland Young's lab in the department of Biochemistry and Biophysics. After, Dr. Kaspar received his PhD from the University of Florida College of Medicine Graduate Program in Biomedical Sciences on the Microbiology/Immunology focused track while performing his graduate studies within Dr. Robert Burne's lab in the College of Dentistry. Dr. Kaspar's PhD project involved studying the integration of streptococcal stress tolerance in cell-cell (peptide-based) signaling and received an F31 fellowship from the NIH and NIDCR. Following graduation, Dr. Kaspar remained within the lab of Dr. Robert Burne at the University of Florida College of Dentistry while shifting his research focuses to intermicrobial interactions that occur within the oral supragingival biofilms that was supported with an NIH/NIDCR F32 fellowship.

Research Interests

Dr. Kaspar's research interests center on the microbial interactions that occur within the human oral cavity. Specifically, the lab is exploring physical contact-dependent interactions between early colonizers of supragingival biofilm communities and pathogens such as Streptococcus mutans that drive sequential changes within the microbiome during initial colonization and subsequent biofilm formation. Additionally we have interests in the biogeography or spatial arrangement of bacteria within oral biofilms, how it can be modified and the role of the spatial arrangement in cooperative/antagonistic interactions between bacterial species. Finally, we continue to study Gram-positive bacterial communication in the form of peptide or 'pheromone' signaling through detailing specific pathway(s) in oral streptococci in terms of the gene(s) the peptide signaling systems regulate, their role in bacterial fitness and their effect on the larger bacterial community and/or microbiome.

Research Summary

Bacteria within multispecies communities grow and persist in complex environments by competing over scare resources such as nutrients and physical space. The human oral cavity is ideally suited as a model for the dissection of interspecies interactions. In the human mouth, billions of microbes belonging to over 700 independent taxa function cooperatively and/or antagonistically to shape the composition of the microbiome. These interactions, coupled with frequent environmental perturbations, can also disrupt microbial homeostasis; which can lead to the ecological shifts observed during development of oral diseases. For example, as is the case for dental caries, increases in the proportions of strongly acidogenic and acid tolerant bacteria, such as the mutans streptococci, are observed when bacterial fermentation of dietary carbohydrates repeatedly acidifies microbial biofilms, leading to demineralization of the tooth. Concurrently, health-associated commensal streptococci, which are less constitutionally resistant to low pH, decrease in proportions. Loss of these species compounds the problem as many of these commensal streptococci provide protection from caries development by metabolizing arginine via the arginine deiminase system (ADS), which elevates the pH through release of ammonia. Further, many commensal streptococci can directly inhibit growth and/or expression of virulence traits by mutans streptococci through multiple strategies; with the generation of hydrogen peroxide being a significant deterrent to growth of Streptococcus mutans and other oral pathogens. Research within the Kaspar Lab focuses on dissecting how S. mutans responds to health-associated oral Streptococcus species that occupy the same niche and how these responses may be modulated for development of novel therapeutic approaches.

Justin Kaspar
Office Address

4179 Postle Hall
305 W. 12th Ave.
Columbus, OH 43210
United States

Lab Address

4185 Postle Hall
305 W. 12th Ave.
43210 OH

Academic Division