University of Pennsylvania, Philadelphia, PA
Ohio State University, Columbus, OH
University of Rochester
My research focuses on development of the digestive system and effects of nanoparticles exposure. I use zebrafish, which is an excellent model research organism. Transparent zebrafish embryos develop externally over the course of five days. At the end of embryogenesis there is a similar arrangement of digestive organs and cell types when compared to humans. Zebrafish embryos also have extensive similarties to the genetics and physiology of human organ development with broad implications for human development and disease states.
Developmental regulation of the intestinal epithelial stem cell compartment. The intestinal epithelium continuously replaces cells that undergo apoptosis. Cells proliferate in the crypts at the base of the villi to replace lost epithelial cells. While there is intense investigation into the signals controlling proliferation of crypt epithelial cells, little is known about the formation of the developing stem cell niche. We are investigating epithelial cells that play a role in regulation proliferation of the developing stem cell niche using zebrafish as a model system.
Nanoparticle affects due to environmental exposure. Nanoparticles are being incorporated into a number of manufactured commercial products. Physiochemical properties of material at the nanoscale act differently than their bulk counterparts. Using the zebrafish model system in collaboration with Dr. Silvana Andreescu in Chemistry we are assessing the biocompatibility of nanoparticles of different compositions. Electrochemical sensors are being developed to detect Nitric Oxide and Reactive Oxygen Species to determine physiological changes resulting from nanoparticle exposure.
To investigate these topics, I am using mutant analysis, molecular biology techniques, histology, immunohistochemistry, RNA in situ hybridization, and antisense technology to knock down gene function in developing embryos. Each of these techniques is a powerful tool to identify molecular pathways involved in digestive development and function.
Njagi, J, Ball, M.*, Best, M.*, Wallace, K.N., and Andreescu, E.S. (2010) Electrochemical quantification of serotonin in the embryonic zebrafish intestine. Analytical Chemistry, 82(5): 1822-1830.
Özel, R.E., Wallace, K.N., Andreescu S. (2011) Chitosan coated carbon fiber microelectrode for selective in vivo detection of neurotransmitters. Analytica Chimica Acta, 695 (1-2): 89-95.
Wallace, K.N. Fish digestive development. (2011) Encyclopedia of Fish Physiology. Eds. Farrell, T and Stevens, D., Elsevier.
Andreescu S., Gheorghiu, M, Ozel, R.E., Wallace, K.N. (2011) Mehodologies for Toxicity Monitoring and Nanotechnology Risk Assessment. Biotechnology and Nanotechnology Risk Assessment. Ed. Ripp, , ACS Books.
Özel, R.E., Wallace, K.N., Andreescu S. (2011) Chitosan coated carbon fiber microelectrode for selective in vivo detection of neurotransmitters. Analytica Chimica Acta, 695 (1-2): 89-95. PMID: 21601035
Roach,G.#, Wallace, R.H., Cameron, A.*, Ozel, R.E., Hongay, C.F., Baral, R., Andreescu, S., and Wallace, K.N. (2013) Loss of ascl1a prevents secretory cell differentiation within the zebrafish intestinal epithelium resulting in a loss of distal intestinal motility. Developmental Biology, 376(2):171-186. PMID: 23353550
Özel, R.E., Alkasir, R.S.J., Ray, K.*, Wallace, K.N., Andreescu, S. (2013) Comparative Evaluation of Intestinal Nitric Oxide in Embryonic Zebrafish Exposed to Metal Oxide Nanoparticles. Small, 9 (24), 4250-4261. PMID: 23873807
Özel, R.E., Hayat, A., Wallace, K.N., Andreescu, S.A., (2013) Effect of cerium oxide nanoparticles on intestinal serotonin in zebrafish. RSC Advances, 3 (35), 15296-15309. PMID: 24015353
Özel, RE, Wallace, KN, Andreescu, S. (2014) Alterations of intestinal serotonin following nanoparticle exposure in embryonic zebrafish. Environmental Science: Nano 1, 27-36. PMID 24639893
Baral R. Wetie AG, Darie CC, Wallace KN. (2014) Mass spectometry for proteomics-based investigation using the zebrafish model system. Adv Exp Med Biol. 2014;806:331-40. PMID: 24952190
(* denotes undergraduate co-author, # denotes Masters student who began as an undergraduate.)