Louisiana State University, Ph.D. 2009
Dr. Bitoun received his Bachelor of Science in Biochemistry from Louisiana State University in 2004. He then received his Ph.D. in Biochemistry from Louisiana State University in 2009. Dr. Bitoun currently trains as a post-doctoral researcher in the laboratory of Dr. Z. Tom Wen at Louisiana State University, School of Dentistry.
Dr. Bitoun’s current research focuses on elucidating virulence factors and stress response pathways in the cariogenic bacterium, Streptococcus mutans. Microbial biofilms, such as dental plaque, are complex surface-attached assemblages of multi-species organisms that have evolved communally to live in a particular niche. Microbial biofilms are more resistant to antibiotics than their planktonic counterparts and can cause life threatening infections. The oral cavity is home to one of the most diverse ecosystems on Earth and under normal, non-diseased conditions, any person can harbor around 200 different microbial species in the mouth. The oral cavity is one of the five sites of the body that the Human Microbiome Project has analyzed, and the Human Oral Microbiome Database currently has over 600 microbial taxa curated. Dr. Bitoun is interested in understanding the factors contributing to multi-species oral biofilm development, dispersion, and host response to lead to more precise therapies of microbial infections.
Previously, Dr. Bitoun researched the biogenesis of iron-sulfur (Fe-S) clusters in the laboratory of Huangen Ding at LSU in Baton Rouge. Fe-S clusters are ubiquitous protein bound cofactors involved in a variety of cellular functions including electron transport, central metabolism, gene regulation, DNA replication and repair, and tRNA modification. The most common types of Fe-S clusters are the rhombic [2Fe-2S] and cubane [4Fe-4S] although other [8Fe-8S] and mixed metal clusters can be formed. The structural versatility, broad chemical reactivity, and abundance of iron and sulfur in the probiotic Earth enhanced selective pressure for their incorporation into proteins for evolving life forms. In redox-active Fe-S clusters, iron cycles between oxidation states of ferric (Fe3+) and ferrous (Fe2+) with sulfur remaining in the sulfide (S2-) oxidation state. Fe-S proteins remain a topic of great interest.
Biofilms, Streptococcus mutans, Oxidative Stress, Iron-Sulfur Proteins, Free Radicals
Bitoun, J.P., Liao, S., McKey, B.A., Yao, X., Abranches, J., Beatty, W.L., and Wen, Z.T. 2013. Psr is involved in Regulation of Glucan Production and Double Deficiency of BrpA and Psr is Lethal in Streptococcus mutans. Microbiology 159(Pt 3): 493-506.
Bitoun, J.P., Liao, S., Yao, X., Xie, G.G., and Wen, Z.T. 2012. The Redox-Sensing Regulator Rex Modulates Central Carbon Metabolism, Stress Tolerance Response, and Biofilm Formation in Streptococcus mutans. PLoS ONE 7(9): e44766.
Bitoun, J.P., Liao, S., Yao, X., Ahn, S.J., Isoda, R., Nguyen, A.H., Brady, L.J., Burne, R.A., Abranches, J., and Wen, Z.T. 2011. BrpA is Involved in Regulation of Cell Envelope Stress Responses in Streptococcus mutans. Appl Environ Microbiol 78(8): 2914-22.
Bitoun, J.P., Nguyen, A.H., Fan, Y., Burne, R.A., and Wen, Z.T. 2011. Transcriptional Repressor Rex is Involved in Regulation of Oxidative Stress Response and Biofilm Formation by Streptococcus mutans. FEMS Microbiol Lett 320(2): 110-17.
Wen, Z.T., Nguyen, A.H., Bitoun, J.P., Abranches, J., Baker, H.V., and Burne, R.A. 2011. Transcriptome Analysis of LuxS-deficient Streptococcus mutans Grown in Biofilms. Mol Oral Microbiol 26(1): 2-18.
Lu J., Bitoun, J.P., Tan G., Wang W., Min W., and Ding H. 2010. Iron Binding Activity of Human Iron-Sulfur Cluster Assembly Protein hIscA-1. Biochem J 428(1): 125-31.
Tan, G., Lu, J., Bitoun, J.P., Huang, H., and Ding, H. 2009. IscA/SufA Paralogs Are Required for the [4Fe-4S] Cluster Assembly in Enzymes of Multiple Physiological Pathways in Escherichia coli under Aerobic Growth Conditions. Biochem J 420(3): 463-72.
Bitoun, J.P., Wu, G., and Ding, H. 2008. Escherichia coli FtnA Acts as an Iron Buffer for the Re-assembly of Iron-Sulfur Clusters in Response to Hydrogen Peroxide Stress. Biometals 21(6): 693-703.
Yang, J., Bitoun, J.P., and Ding, H. 2006. Interplay of IscA and IscU in the Biogenesis of Iron-Sulfur Clusters. J Biol Chem 281(38): 27956-63.