Govindsamy Vediyappan, Assistant Professor
339 Ackert Hall
Ph.D., 1994, University of Madras, India.
Area(s) of Specialization
Medical mycology, fungi-bacteria interactions, bacterial multidrug resistance (MDR) efflux pumps, and antimicrobial development.
Candida albicans is commensal and an opportunistic human fungal pathogen. Humans being the natural host, C. albicans resides in the oral, gastrointestinal tract and the urogenital tracts. C. albicans and other Candida species cause mucosal, disseminated and invasive infections, especially among patients who are immune-suppressed or hospitalized with diseases such as cancer or HIV. The fungus also interacts synergistically with certain bacteria in the oral cavity forming mixed biofilms and augments both bacterial and fungal virulence.
A better understanding of C. albicans virulence, particularly its yeast-to-hypha conversion and hyphal growth, will allow us to design novel intervention strategies. Unlike several classes of antibacterial drugs available for treatments, there are only three major classes of antifungals exist for treatments. To address this unmet medical need, we are characterizing bioactive small molecules from natural and synthetic products for their antivirulence/antifungal properties, and determining their mode-of-actions (MOA) using molecular, genetic and biochemical approaches.
We are also interested in deciphering the molecular mechanisms of antimicrobial resistance in bacterial pathogens, particularly the contribution of multiple drug resistance (MDR) by efflux pumps, which extrudes drugs from the bacteria. Active drug efflux is one of the major intrinsic mechanisms of MDR in bacteria and contributes clinically relevant drug resistance. A single MDR efflux pump system (e.g. AcrAB-TolC) can effectively remove hundreds of structurally diverse antimicrobial drugs from bacterial cells leading to therapeutic failures in clinics. Understanding MDR efflux pumps in bacteria, including efflux pump inhibitors (EPI), will allow us to develop effective therapeutics against bacterial pathogens.
Horn C, and Vediyappan G. 2021. Anticapsular and Antifungal Activity of α-Cyperone.Antibiotics, 10:51. doi: 10.3390/antibiotics10010051. PMID: 33419126.
Edouarzin E, Horn C, Paudyal A, Zhang C, Lu J, Tong Z, Giaever G, Nislow C, Veerapandian R, Hua DH, Vediyappan G.. 2020. Broad-spectrum antifungal activities and mechanism of drimane sesquiterpenoids. Microb Cell. 2020 Mar 12;7(6):146-159. doi: 10.15698/mic2020.06.719.PMID: 32548177 Free PMC article.
Veerapandian R, Paudyal A, Chang A, Vediyappan G.. 2020. Separation of Bioactive Small Molecules, Peptide from Natural Source and Proteins from Microbe by Preparative Isoelectric Focusing (IEF) Method. J Vis Exp. 2020 Jun 14;(160). doi: 10.3791/61101.PMID: 32597857
Veerapandian, R., and G. Vediyappan. 2019. Gymnemic Acids Inhibit Adhesive Nanofibrillar Mediated Streptococcus gordonii-Candida albicans Mono-Species and Dual-Species Biofilms. Front Microbiol. 2019 Oct 11;10:2328. doi: 10.3389/fmicb.2019.02328. eCollection 2019. PMID:31681200.
Vediyappan G. , V. Dumontet, F. Pelisser and C. d’Enfert. 2013. Gymnemic acids inhibit hyphal growth and virulence in Candida albicans. PLOS ONE 8: e74189, PMID: 24040201. http://www.k-state.edu/media/newsreleases/jun13/vediyappan91213.html
Barabote, R.D., J. Thekkiniath, R.E. Strauss, G. Vediyappan, J.A. Fralick and M.J. San Francisco. 2011. Xenobiotic efflux in bacteria and fungi: a genomics update. Adv. Enzymol. Relat. Areas Mol. Biol. 77:237-306, PMID: 21692371, Review (Editor Toone, E.J., Publisher: John Wiley & Sons, Inc.)
Vediyappan G, T. Rossignol, and C. d'Enfert. 2010. Interaction of Candida albicans biofilms with antifungals: transcriptional response and binding of antifungals to beta-glucans. Antimicrob Agents Chemother. 54(5):2096-111.
Govind, R., G. Vediyappan, R.D. Rolfe, B. Dupuy, and J.A. Fralick. 2009. Bacteriophage mediated toxin gene regulation in Clostridium difficile. J. Virology 83 (23):12037-45.
Enjalbert, B., A. Rachini, G. Vediyappan, D. Pietrella, R. Spaccapelo, A. Vecchiarelli, A.J. Brown, and C. d'Enfert. 2009. A multifunctional, synthetic Gaussia princeps luciferase reporter for live imaging of Candida albicans infections. Infect Immun. 77(11):4847-58.
Vediyappan G, Raja Rao GK, and Rudreshan B. 1998. Properties of extracellular chitinase from Myrothecium verrucaria, an antagonist to the groundnut rust, Puccinia arachidis. Can. J. Plant Pathology. 20:62-68.
Vediyappan Govindsamy and Rudreshan Balasubramanian. 1994. Purification and properties of apoplastic chitinases from rust infected leaves of Arachis hypogaea L. Botanica Helvetica. 104:79-86.