Molecular mechanism and functional significance of acid generation in the Drosophila midgut

Overend, G., Luo, Y., Henderson, L., Douglas, A. E., Davies, S. A. and Dow, J. A.T. (2016) Molecular mechanism and functional significance of acid generation in the Drosophila midgut. Scientific Reports, 6, 27242. (doi:10.1038/srep27242) (PMID:27250760) (PMCID:PMC4890030)

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Abstract

The gut of Drosophila melanogaster includes a proximal acidic region (~pH 2), however the genome lacks the H+/K+ ATPase characteristic of the mammalian gastric parietal cell, and the molecular mechanisms of acid generation are poorly understood. Here, we show that maintenance of the low pH of the acidic region is dependent on H+ V-ATPase, together with carbonic anhydrase and five further transporters or channels that mediate K+, Cl− and HCO3− transport. Abrogation of the low pH did not influence larval survival under standard laboratory conditions, but was deleterious for insects subjected to high Na+ or K+ load. Insects with elevated pH in the acidic region displayed increased susceptibility to Pseudomonas pathogens and increased abundance of key members of the gut microbiota (Acetobacter and Lactobacillus), suggesting that the acidic region has bacteriostatic or bacteriocidal activity. Conversely, the pH of the acidic region was significantly reduced in germ-free Drosophila, indicative of a role of the gut bacteria in shaping the pH conditions of the gut. These results demonstrate that the acidic gut region protects the insect and gut microbiome from pathological disruption, and shed light on the mechanisms by which low pH can be maintained in the absence of H+, K+ ATPase.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Dow, Professor Julian and Henderson, Ms Louise and Davies, Professor Shireen and Overend, Dr Gayle
Authors: Overend, G., Luo, Y., Henderson, L., Douglas, A. E., Davies, S. A., and Dow, J. A.T.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Scientific Reports
Publisher:Nature Publishing Group
ISSN:2045-2322
ISSN (Online):2045-2322
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Scientific Reports 6:27242
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
571431Extraordinary pH - the mechanism of generation of pH 12 in living systemsJulian DowBiotechnology and Biological Sciences Research Council (BBSRC)BB/J002143/1RI MOLECULAR CELL & SYSTEMS BIOLOGY