The most prominent organ of larval mosquitoes is the stomach, which makes up the major part of the gastrointestinal tract. This organ is of prominent importance for ionic, volume and acid/base homeostasis. The anterior stomach actively secretes alkali equivalents, generating a compartment of extremely high pH which is of importance for digestion, but also for the susceptibility to biological control agents such as Bacillus thuringienis endotoxin. In the posterior stomach the pH returns to almost neutral values by recovery of alkali equivalents. Most likely, this cycle involves a high turnover of acid/base equivalents as well as of sodium and chloride ions. The processes of ion transport, their regulation and their coordination with peristalsis in the stomach of larval mosquitoes are poorly understood. The project is directed at understanding these processes in two mosquito species: the yellow fever mosquito (Aedes aegypti) and the malaria mosquito of subsaharan Africa Anopheles gambiae. Specifically we will determine: 1. the ion transport mechanisms involved in alkalization of the anterior stomach. 2. the ion transport mechanisms involved in reacidification of the posterior stomach. 3. the mechanisms of regulation of ion transport in the anterior and posterior stomach. 4. the mechanisms of coordination of ion transport with peristalsis in the anterior and posterior stomach. The studies will be carried out, using mainly five different methodological approaches: 1.) Electrophysiological characterization of ion transport across isolated stomach segments and its regulation, using conventional transepithelial techniques and microelectrodes 2.) Analyses of luminal pH changes with isolated stomach segments, using pH indicators and/or pH sensitive microelectrodes in the perfusate 3.) Histochemical and immunhistochemical localization of involved transporters and regulative units/systems 4.) Biochemical determination of transporter activities and their regulation by hormonal/non-hormonal factors 5.) Analyses of peristalsis and its regulation with electrophysiological techniques and image analyses. The results of this project will provide information about specific targets for the development of mosquito control agents.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Special Emphasis Panel (ZRG1-VB-P (01))
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Costero, Adriana
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Washington State University
Schools of Arts and Sciences
United States
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Petrova, Adelina; Moffett, David Franklin (2016) Comprehensive Immunolocalization Studies of a Putative Serotonin Receptor from the Alimentary Canal of Aedes aegypti Larvae Suggest Its Diverse Roles in Digestion and Homeostasis. PLoS One 11:e0146587
Onken, Horst; Moffett, David F (2015) Fluid absorption in the isolated midgut of adult female yellow fever mosquitoes (Aedes aegypti). J Exp Biol 218:2023-9
Moffett, David F; Jagadeshwaran, Urmila; Wang, Zeping et al. (2012) Signaling by intracellular Ca2+ and H+ in larval mosquito (Aedes aegypti) midgut epithelium in response to serosal serotonin and lumen pH. J Insect Physiol 58:506-12
Onken, Horst; Moffett, David F (2009) Revisiting the cellular mechanisms of strong luminal alkalinization in the anterior midgut of larval mosquitoes. J Exp Biol 212:373-7
Izeirovski, Sejmir; Moffett, Stacia B; Moffett, David F et al. (2009) The anterior midgut of larval yellow fever mosquitoes (Aedes aegypti): effects of amino acids, dicarboxylic acids, and glucose on the transepithelial voltage and strong luminal alkalinization. J Exp Zool A Ecol Genet Physiol 311:719-26
Onken, Horst; Patel, Malay; Javoroncov, Margarita et al. (2009) Strong alkalinization in the anterior midgut of larval yellow fever mosquitoes (Aedes aegypti): involvement of luminal Na+/K+-ATPase. J Exp Zool A Ecol Genet Physiol 311:155-61
Bernick, E P; Moffett, S B; Moffett, D F (2008) Ultrastructure and morphology of midgut visceral muscle in early pupal Aedes aegypti mosquitoes. Tissue Cell 40:127-41
Onken, Horst; Moffett, Stacia B; Moffett, David F (2008) Alkalinization in the isolated and perfused anterior midgut of the larval mosquito, Aedes aegypti. J Insect Sci 8:1-20
Bernick, E P; Moffett, S B; Moffett, D F (2007) Organization, ultrastructure, and development of midgut visceral muscle in larval Aedes aegypti. Tissue Cell 39:277-92