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Okech Laboratory Research

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Bernard A. Okech, MS, PHD
Research Assistant Professor, Environmental and Global Health and Emerging Pathogens
Also Affiliate Assistant Professor, Center for African Studies, UF

Contact Information

Department of Environmental and Global Health
College of Public Health and Health Professions
Emerging Pathogens Institute (Lab) Office # 116
2055 Mowry Road, Gainesville FL 32610
University of Florida
Email: bokech@phhp.ufl.edu
Tel: 352-273-5254
Fax: 352-273-6070

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My lab conducts research on three broad areas:
Environmental factors affecting mosquito fitness, survival, vector competence.
Nutritional Regulation of Midgut Proteins Expression in the Mosquitoes.
Epidemiology of malaria infection and anti-malarial drug resistance.

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Research in Dr Okech’s lab examines the midgut of mosquitoes and the proteins that serve the function of transporting essential nutrients such as sugars, proteins and ions that are essential for mosquito survival. Using sophisticated techniques, Dr Okech can visualize these proteins in the midgut of larva and adult mosquitoes and use that information to develop cellular models that give physiological insights to the functions of the midgut and how these functions are related to survival of the mosquito and transmission of pathogens. Detailed understanding of these processes may aid rapid development of new techniques and tools offering the potential to reduce disease vector populations to prevent pathogen transmission. A key area of Dr. Okech’s research looks at how changing micro-environments affect nutrient uptake and pathogen development in the mosquito midgut. Dr Okech studies species of mosquitoes that transmit malaria, filariasis and arboviruses in developing countries of Africa and the Caribbean. Other areas of research by Dr Okech include malaria drug resistance studies and dengue eco-epidemiology in Haiti. .

Project 1: Nutrient Transport Proteins in Midgut of Mosquitoes
The goal is better understand the physiology of the mosquito midgut as a basis to understand mosquito-pathogen interaction and to aid in the development of new methods for mosquito control. Our results have shown that the uptake of amino acid is highly partitioned within the midgut of mosquito larvae (see left panel figure below) and that amino acid and ion transporters interact for optimal nutrient transport (see right panel figure below)..

Project 2: Environmental Effects on Mosquito Fitness, Survival and Vector Competence
Pathogen development in the mosquito may be influenced by the aquatic habitat conditions where the mosquito emerges, the ambient temperature of the adult mosquito resting site and the nutrition resources of the mosquito. Working with the Plasmodium-Anopheles model, Dr Okech’s research looks at these three factors (aquatic habitat, temperature and nutrition) independently and how they affect mosquito survival and malaria parasite transmission. A particular focus of Dr. Okech’s research looks at the effect of chemical and nutritional components of aquatic habitats on nutrient uptake, mosquito fitness and pathogen transmission by mosquitoes.

Project 3: Anti-malarial Drug Resistance in Haiti
Many countries face serious problems with anti-malarial drug resistance. Haiti has continued to use chloroquine for malaria treatment with apparently no evidence of drug resistance. Dr Okech is developing a new research project to look at malaria parasite infections and drug resistance genes in six clinics in Haiti. Information obtained may guide and help improve malaria management in Haiti.

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Harvey WR, Okech BA, Linser PJ, Becnel JJ, Ahearn GA, Sterling KM. 2010. H(+)V-ATPase-energized transporters in brush border membrane vesicles from whole larvae of Aedes aegypti. J Insect Physiol. 56(10):1377-89
Harvey, W.R. and Okech, B.A. (2010) H+, Na+, K+ and Amino acid transport in Caterpillar and Larval Mosquito Alimentary Canal. In Epithelial Transport Physiology, Editor G. Gerencser, Humana-Springer Verlag, page 113—148.
Harvey, W.R., Boudko, D.Y and Okech, B.A. (2009) NHEVNAT, H+ V-ATPases Electrically Coupled to Na+: Nutrient Amino acid Transporters (NATs) Constitute Functional Na+/H+ Exchangers (NHEs). Journal of Experimental Biology, 212 (3):347-57
Okech, BA, Meleshkevitch, EA, Miller, MM, Popova, LB Harvey, WR and Boudko, DY (2008). Synergy and Specificity of Two Na+: Amino Acid Symporters in the Alimentary Canal of Model organism, Anopheles gambiae. Journal of Experimental Biology, 211:1594-602.
Okech, BA, Boudko, DY, Harvey, WR (2008) Cationic pathway of pH regulation in Anopheles gambiae larva. Journal of Experimental Biology, 211, 957 – 968.
Rheault, MR, Okech, BA, Keen, SBW, Miller, MM, Meleshkevitch, MM, Linser, PJ, Boudko, DY and Harvey, WR (2007). Molecular Cloning, Phylogeny and Localization of a First Alkali Metal Ion/Hydrogen Ion Antiporter a Metazoan Anopheles gambiae (AgNHA1). Journal of Experimental Biology, 210, 3848 -3861.
Okech, B, Arai, M, Matsuoka, H. (2006). The effects of blood feeding and exogenous supply of tryptophan on the quantities of xanthurenic acid in the salivary glands of Anopheles stephensi (Diptera: Culicidae). Biochem Biophys Res Commun, 24;341(4):1113-8
Okech BA, Gouagna LC, Walczak E, Kabiru EW, Beier JC, Yan G, Githure JI. 2004. The development of Plasmodium falciparum malaria in experimentally infected Anopheles gambiae ss (Diptera: Culicidae) under ambient microhabitat temperature in western Kenya. Acta Tropica, 92 (2) 99 – 108.
Okech BA, Gouagna LC, Kabiru, EW, Beier JC, Yan G, Githure JI. 2004. Influence of age and previous diet of Anopheles gambiae (Diptera: Culicidae) on the infectivity of natural Plasmodium falciparum gametocytes from human volunteers. J. Insect Sci., 4, 33.
Okech BA, Gouagna LC, Kabiru EW, Walczak E, Beier JC, Yan G, Githure JI. 2004. Resistance to high temperatures of the early midgut stages of natural isolates Plasmodium falciparum in artificially infected Anopheles gambiae (Diptera: Culicidae) mosquitoes. J. Parasitol., 90 (4) 764 – 768.
Okech BA, Gouagna LC, Killeen GF, Knols BG, Kabiru EW, Beier JC, Yan G, Githure JI. 2003. The influence of sugar availability and indoor microclimate on the survival of Anopheles gambiae under semi field conditions in western Kenya. J. Med. Entomol., 40, 657 – 663.
Bousema JT, Gouagna LC, Meutstege AM, Okech BA, Akim NI, Githure JI, Beier JC, Sauerwein RW. 2004. Treatment failure of pyrimethamine-sulphadoxine and induction of Plasmodium falciparum gametocytaemia in children in western Kenya. Trop Med Int Health.8 (5) 427-430.

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1. Demographic and Symptomologic Information Associated with Malaria Infection and Sickle Cell Anemia in Haiti.
Dayana C. Bermudez

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2. PCR detection of malaria parasites and gametocytes in symptomatic and asymptomatic patients

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3. The effect of cations and anions on the growth and development of Aedes aegypti mosquitoes

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Neglected Tropical Disease Coalition
Global Health Council

Pan American Health Organization

World Health Organization

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