BRIEF PROJECT OBJECTIVES
1. Molecular mechanism of quorum sensing regulation and associated virulence factor expression by dietary phytochemicals in human pathogens.
Objective 1. Determine mechanism of quorum sensing modulation by dietary phytochemicals mediated by Acyl Homoserine Lactone (AHL) (AI-1), Autoinducer-2 (AI-2) and Autoinducer-3 (AI-3) in model systems: Chromobacterium violaceum O26, Agrobacterium tumefaciens A136 (pCF218)(pCF372), A. tumefaciens KYC55 (pJZ372)(pJZ384)(pJZ410) Vibrio harveyi BB170 (luxN::Tn5). Objective 2. Determine the effect of phytochemicals on various virulence functions and virulence related gene expression mediated by quorum sensing in Pseudomonas aeruginosa and Staphylococcus aureus and enterohemorrhagic Escherichia coli (EHEC). Objective 3. Determine the efficacy of phytochemicals with quorum sensing regulatory activity on reducing the virulence (adhesion, biofilm, swarming, lesion, protease activity) in Pseudomonas aeruginosa, Staphylococcus aureus and enterohemorrhagic Escherichia coli (EHEC) using ex vivo porcine skin and intestinal models.
2. A systematic and mechanistic study of in vitro and in vivo immunomodulatory activities of plant secondary metabolites especially relevant to innate immunity.
Objective 1. To determine the effect of specific plant secondary metabolites on innate immunological parameters in Lumbricus terrestris. Specifically, understand their effect on expression and secretion of an array of humoral factors such as agglutinnis and lytic factors. Evaluate their effect on immunological functions of coelomcytes such as phagocytotic activity, oxidative burst and nitric oxide release as well as effect on coelomcyte differentiation into neutrophils. To determine the ability of immunomodulatory phytochemicals to prevent infections and mortality in bacteria challenged Lumbricus terrestris. Objective 2. Effect of phytochemicals on innate immunity signaling in various transgenic Caenorhabditis elegans strains and cell cultures (HL60, NB4, EML and MPRO) using reverse genetics and RNA interference (RNAi) tools. We are specifically interested in genes important for myeloid differentiation and the TLR mediated signaling in innate immune system, leading to the activation of kinases, NF-kB, and direct regulation of immune-responsive genes.
3. Mechanistic evaluation of in vitro cancer chemotherapeutic and anti-retroviral effects of natural product formulations.
Objective 1. Effect of natural products to prevent or reduce physiological processes that are linked to the development and progression of carcinogenesis or carcinogenicity-linked cellular damage in oral cancer cell line (CAL27) and colon carcinoma cell lines HT-29 and HT-116. Investigation on their ability to regulate expression of COX-2, cylcin D1, and apoptotic markers: caspase-3 and poly-ADP-ribose polymerase. Objective 2. Evaluate the anti-retroviral potential of natural products in vitro and describe its mechanism of action in enzymatic and cell culture systems. Regulation of enzyme activities relevant for retroviral therapy such as reverse transcriptase, glycohydrolase and protease. Determine their potential to offer protection against HIV-1-induced lytic effects in cell cultures, induce inhibition of HIV-1 p24 antigen production in chronically infected H9 cells and on Syncytial cell morphology formation.
4. Dietary phytochemicals, redox and nitric oxide (NO) signaling in spermatogenesis and sperm function
Objective 1. To determine the effect of dietary metabolites on oxidative stress and NO signaling in seminal vesicles and its effect on spermatogenesis and sperm function. Specifically, the effect of dietary phytochemicals on redox status, antioxidant enzymes (SOD, catalase), sperm motility, quality and damage to sperm nuclear DNA in Lumbricus terrestris and Caenorhabditis elegans. Objective 2. To understand modulation various signaling pathways by dietary phytochemicals, mediated by ROS and NO which regulate the activation of kinases, PDE and NF-Kb important in spermatogenesis and sperm function using reverse genetics and RNA interference (RNAi) tools.
5. Modulation of energy harvesting ability of the mammalian GI tract by dietary and medicinal plants for managing obesity and co-morbidities.
Objective 1. Mechanism of reduction in energy harvest capacity by inhibiting activity and expression of carbohydrate and lipid digesting enzymes in the intestinal lumen as a therapeutic strategy to control postprandial hyperglycemia, assist in weight management, and manage heart disease. Kinetic and mechanistic studies in cell cultures (HT-29 and Caco-2) and in ex vivo porcine intestinal models.