Dr. Kennedy Wekesa is an Associate Professor of Biology whose research interests focuses on pheromone recognition and signal transduction in the mammalian vomeronasal organ. Chemical signals from the environment regulate a diverse array of animal behaviors, essential for survival and regulation of social interactions. Most animals have developed a dual olfactory system for the recognition of these chemical signals: the main olfactory system, which receives input from olfactory neurons in the nose, and the accessory olfactory system, which receives input from chemosensory neurons in the vomeronasal organs. Although considerable information is now available regarding stimulus recognition, signal transduction and odor coding in the olfactory system, little is known about the repertoire of chemical stimuli that are received via the vomeronasal organ and the transduction pathways they activate. In previous experiments we have shown that compounds in male urine activate the production of the second messenger, inositol-(1,4,5 )-triphosphate, in microvillar membranes from vomeronasal organs of prepubertal females. Stimulus-induced release of inositol-(1,4,5)-triphosphate is, sex dependent, tissue-specific and GTP-dependent, indicating that this process is receptor mediated and involves a regulatory G protein. We are interested in using the inositol-(1,4,5)-trisphosphate responses in murine vomeronasal membranes as a biochemical assay to purify and characterize compounds from male urine that activate the release of inositol- (1,4,5)-trisphosphate in membrane preparations from female vomeronasal organs. We are also interested in determining the contributions of the following G-proteins Gi2, Gi3, G0, and Gq/11, all present in vomeronasal membranes, in regulating stimulus-dependent production of inositol-(1,4,5)-triphosphate in the murine vomeronasl organ. We will further delineate the mechanisms by which stimuli are transduced into neural messages, by determining if the IP3 pathway causes release of intracellular Ca2+ via IP3 receptors on the endoplasmic reticulum or if IP3-sensitive calcium stores are responsible for the release of sequestered calcium in response to stimulation an understanding of which will provide insights into chemical signal transduction in the VN system. These studies will result in characterization of the structure and biochemical signaling properties of one or more biological compounds that activate the vomeronasal organ in a tissue-specific, sex-specific and G-protein dependent manner. Furthermore, increasing our understanding of the diversity of vomeronasal stimuli and their modes of action on the vomeronasal organ may, in the long term, contribute to shedding light on the possible function of vomeronasal organs in humans and the possible impact on vomeronasal stimuli on human physiology and behavior.
Publications
* Thompson, R.N, Napier, A. and Wekesa, K.S. 2007. Chemosensory cues from the lacrimal and preputial glands stimulate production of IP3 in the vomeronasal organ and aggression in male mice. Physiology & Behavior (90): 797-802.
* Thompson, R.N, McMillon, R, Napier, A. and Wekesa, K.S. 2007. Pregnancy block by MHC Class I peptides is mediated via the production of inositol 1,4,5 trisphosphate in the mouse vomeronasal organ. Journal of Experimental Biology (210): 1406-141.
* Thompson, R.N, Napier, A. and Wekesa, K.S. 2006. Attenuation of the production of inositol 1,4,5- trisphosphate in the mouse vomeronasal organ by antibodies against the αq/11 subfamily of G-proteins. Chem. Senses (31): 613-619.
* Thompson, R.N, Robertson, B.K., Napier, A. and Wekesa, K.S. 2004. Sex specific responses to urinary chemicals by the mouse vomeronasal organ. Chem. Senses (29): 749-754.
* Wekesa, K.S, Stephanie Miller and Audrey Napier. 2003. Involvement of Gq/11 in the signal transduction pathway of the mammalian vomeronasal organ. Journal of Experimental Biology (206):827-832.
Associate Professor of Biology, research interests focuses on the molecular interactions that take place during development, organogenesis or regeneration. Currently the focus is examining the molecular interactions that take place during thymus organogenesis. The thymus is an organ that plays a critical role in establishing the immune system of different organisms. It develops from a single primordium that also gives rise to the parathyroid gland. The potential for the thymic rudiment to differentiate into two separately distinctive tissues, serving vastly different purposes, indicates that different molecular pathways are involved in creating these distinctions. Although some genetic markers have been identified as being crucial for thymus development, the interactions of these markers with each other in molecular pathways have yet to be discerned. Two important proteins involved in thymus organogenesis are the products of the Hoxa3 gene and the Pax1 gene. Mice that are homozygous mutant for the Hoxa3 gene (Hoxa3 -/-) do not form a thymus and usually die before or soon after birth. Mice that are homozygous mutant for Pax1 (Pax1 -/-) form a thymus; however, the size of the thymus is smaller than normal. In addition, the number of thymocytes present in the thymus of the Pax1 -/- mutant is decreased.
The goal of this study is to elucidate some of the molecular mechanisms that contribute to normal thymus development. The focus of this project will target two specific areas. First, the interaction between Hoxa3 and Pax1 products will be assayed to determine if the interaction is direct regulation of the Pax1 gene by the Hoxa3 protein. Furthermore, information on the region responsible for regulating the Pax1 gene will be explored. Understanding the mechanism of interaction of these two genes should provide some insight into how thymus organogenesis occurs.
Publications
* Thompson, R.N, McMillon, R, Napier, A. and Wekesa, K.S. 2007. Pregnancy block by MHC Class I peptides is mediated via the production of inositol 1,4,5 trisphosphate in the mouse vomeronasal organ. Journal of Experimental Biology (210): 1406-1412.
* Thompson, R.N, Napier, A. and Wekesa, K.S. 2007. Chemosensory cues from the lacrimal and preputial glands stimulate production of IP3 in the vomeronasal organ and aggression in male mice. Physiology & Behavior (90): 797-802.
* Thompson, R.N, Napier, A. and Wekesa, K.S. 2006. Attenuation of the production of inositol 1,4,5- trisphosphate in the mouse vomeronasal organ by antibodies against the aq/11 subfamily of G-proteins. Chem. Senses (31): 613-619.
* Wekesa, K. S., Thompson, R., Robertson, B. K., Napier, A. 2004. Sex specific responses to urinary chemicals by the mouse vomeronasal organ. Chemical Senses. 29(9):749-54.
* Wekesa, K.S, Stephanie Miller and Audrey Napier. 2003. Involvement of Gq/11 in the signal transduction pathway of the mammalian vomeronasal organ. Journal of Experimental Biology (206):827-832.
The research focus of Dr. Douglas Strout, Associate Professor of Chemistry, is the theoretical model of novel energy sources for medical nanotechnology applications .
Molecules consisting primarily of nitrogen are being studied by the use of theoretical models to determine the potential of the molecules to serve as high energy density materials (HEDM). Many molecules consisting entirely of nitrogen have been previously shown to be too unstable to be HEDM, which is why heteroatoms are incorporated in the structures in this research project. The molecules are still highly energetic because of the high nitrogen content, but the heteroatoms provide the necessary stability required of a practical HEDM.
Dr. Srout plans for the project include a complete study of isomers of N18C6H6 to determine the factors that lead to stability and compare the results to the previous study of N24. Also, he plans to revisit the n12 and N6C6H6 molecules to determine if the nitrogen-richness of N6C6H6 can be enhanced without loss of stability, determine the role, if any, of the hydrogen in the stability of nitrogen-carbon-hydrogen cages and utilize the PBE1PBE method in the calculation of molecular properties, which has recently been shown to outperform the previously –used B3LYP method.
Publications
* Kamilah Williams and Strout, Douglas L. 2007. Ring Strain Effects in Conjugated Polyenes. Journal of Undergraduate Chemistry Research. 1, 11
* R. Cottrell, J. Jones, A. Gilchrist, D. Shields and Strout, D.L. 2006. Stability of High-Energy N14H14 2+ Ion and the Effects of Carbon and Halogen Substitution. J. Phys. Chem. A. 110,9011.
* R Cottrell, D. McAdory, J. Jones, A.Gilchrist, D. Shield and Strout, D. L. 2006. Isomer Stabilty and Bond-Breaking Energies of N8C8H8 Cages. J. Phys.Chem. A. 110, 13889
* Strout,D.L. 2005. Why isn’t the N20 dodecahedron ideal for three-coordinate nitrogen? J. Phys. Chem. A 109, 1478.
* Strout, D.L. 2005. Stabilization of cylindrical N12 and N18 by phosphorus substitution. J. Phys. Chem. Theory Comput. 1, 561.
* Colvin, K.D., Strout, D.L. 2005. Stabilization of nitrogen-oxygen cages N12O2, N14O2, N14O3,and N16O4. J. Phys. Chem. A 109, 8011.
* Strout, D.L. 2004. Fullerene-like cages versus alternant cages: Isomer stability B13N13, B14N14, and B16N16. Chems. Phys. Lett. 383, 95.
* Strout, D.L. 2004. Isomer stability of N24N30, and N36 : Cyclindrical versus spherical structure. J. Phys. Chem. A 108, 2555.
* Strout, D.L., Strurdivant, S.E. 2004. Beyond N8O6: Length effects and end-cap effects on the stability of a hexagonal nitrogen tube. J. Phys. A 108, 4773.
* Nelson, F.A., Strout, D.L., Strurdivant, S.E. 2004. Trends in stability for N18 cages. J. Phys. Chem. A108, 7087.
* Strout, D.L. 2004. Cage isomers of N14 and N16 : Nitrogen molecules that are not a multiple of six. J. Phys. Chem. A 108, 10911.
Dr. Shree Singh is an Associate Professor of Biology whose current research project goal is to assess immune response to DNA vaccine in combination with recombinant protein against RSV. Our laboratory is currently involved in projects with goals to develop diagnostic tools, vaccine and therapeutics against human Respiratory Syncytial Virus (RSV) and Chlamydia. RSV causes upper and lower respiratory tract infection in almost all children and is life threatening in immunocompromised individuals. These projects are performed in collaboration with Tulane University, Univ. of Florida, University of South Florida and University of Louisville.
Recombinant DNA and protein based mucosal vaccine against RSV: The objective of this project is to clone antigenic regions of RSV genes either into a bacterial vector or a DNA expression vector. Following development of these vectors purified protein or DNA vectors are used to study immune response in animals.
Adeno-associated Virus based vaccines: Similar to DNA vaccine vector, we are using AAV as vaccine delivery tool to improve expression of the antigenic regions.
RSV gene silencing using siRNA technology-This project aims at developing therapeutic agents against RSV using siRNA technology.
Studies of RSV virion structure using AFM- The host cell receptor that RSV utilizes to bind and infect has not been identified. Our goal is to study the cell surface molecules using various methods including atomic force microscopy. This project may help in future development of anti-RSV drugs.
Biosensors to diagnose RSV and other diseases- Our aim in this project is to develop DNA based biosensors which can provide effective and economical diagnosis of RSV and other microorganisms.
Publications
*Zekri, S., A. Kumar, S.R. Singh. 2007. Analysis of mesocavity DNA biochip for respiratory syncytial virus (RSV) diagnosis. J. Biomed. Nanotechnol. 3 (2):139-147.
*Singh, S. R., V. A. Dennis,C. L. Carter, S. R. Pillai, E. G. Moore. 2007.Respiratory Syncytial Virus Recombinant F protein (residues 255-278) induces a helper T cell type 1 immune response in mice. Viral Immunol. 20 (2): 261-75.
*Singh SR, Dennie VA, Carter CL, Pillai SR, Jefferson A, Sahi SV, Moore EG. 2007. Immunogencity and efficacy of recombinant RSV-F vaccine in a mouse model. Vaccine. 25(33):6211-23.
*Dennis, V.A., A. Jefferson, S.R. Singh, F. Ganapamo, M.T. Phillip. 2006. Interleukin-10 anti-inflammatory response to Borrelia burgdorferi, the agent of Lyme disease: a possible role for suppression of cytokine signalling 1 and 3. Infect. Immun. 74 (10):5780-89.
*Singh SR, Hulett K., Pillai SR, Dennis VA, Oh MK, Scissum-Gunn K. 2006. Mucosal immunization with recombinant MOMP genetically linked with modified cholera toxin confers protection against Chlamydia trachomatis infection. Vaccine. (24): 1213-24.