Cell Physiology of the Drosophila midgut

The Tata Institute of Fundamental Research introduced the midgut of Drosophila in 2005 as a model organ for studying the physiology of the gastrointestinal tract. Detailed cell physiology of microperfused gut segments and unperfused segments can be studied with full control of all transport conditions like solution composition on both sides of the epithelial cells, transepithelial potential, and hydrostatic pressure. It is among the rare tubular structures that can be voltage-clamped, with direct control of voltage-dependent proton pumping in an intact epithelium.

	I will describe the stereological ultrastructure of individual gut segments to highlight the importance of accurate geometric measurements in arriving at high quality transport parameters at the single cell or single membrane level. I will give illustrative examples of how one can quantitatively analyze the transport of major electrolytes and water and predict the localization of membrane transporters, which promises to be a rich field for cell biologists interested in the regulation of epithelial function. Finally, I will show how physiological signatures can be read to decipher innate immunity in insect epithelia.