The University of Southampton
University of Southampton Institutional Repository

In situ analysis of pH gradients in mosquito larvae using non-invasive, self-referencing, pH-sensitive microelectrodes

In situ analysis of pH gradients in mosquito larvae using non-invasive, self-referencing, pH-sensitive microelectrodes
In situ analysis of pH gradients in mosquito larvae using non-invasive, self-referencing, pH-sensitive microelectrodes
The alkaline environment, pH approximately 11, in the anterior midgut lumen of mosquito larvae is essential for normal nutrition and development. The mechanism of alkalization is, however, unknown. Although evidence from immunohistochemistry, electron microscopy and electrophysiology suggests that a V-ATPase is present in the basal membranes of the epithelial cells, its physiological role in the alkalization process has not been demonstrated. To investigate a possible role of the V-ATPase in lumen alkalization, pH gradients emanating from the hemolymph side of the midgut in semi-intact mosquito larvae were measured using non-invasive, self-referencing, ion-selective microelectrodes (SERIS). Large H+ concentration gradients, with highest concentrations close to the basal membrane (outward [H+] gradients), were found in the anterior midgut, whereas much smaller gradients, with concentrations lowest close to this membrane (inward [H+] gradients), were found in the gastric caeca and posterior midgut. Similar region-specific pH gradients, with consistent anterior-to-posterior profiles, were observed in individuals of two Aedes species, Aedes aegypti from semi-tropical Florida and Aedes canadensis from north-temperate Massachusetts. The gradients remained in a steady state for up to 6 h, the maximum duration of the recordings. Bafilomycin A1 (10(-5), 10(-7 )mol x l(-1)) on the hemolymph side greatly diminished the [H+] gradients in the anterior midgut but had no effect on the gradients in the gastric caecum and posterior midgut. These physiological data are consistent with the previous findings noted above. Together, they support the hypothesis that a basal, electrogenic H+ V-ATPase energizes luminal alkalization in the anterior midgut of larval mosquitoes.
0022-0949
691-699
Boudko, D.Y.
02ce9c4a-2862-4aa1-a21f-15273775f1bb
Moroz, L.L.
7c26e891-4e40-468e-ad2f-ec618b64700f
Linser, P.J.
30580957-e396-451c-9293-ef92ea2c6dfb
Trimarchi, J.R.
ed60c317-c345-4d45-b1bf-22196e05ff55
Smith, P.J.
003de469-9420-4f12-8f0e-8e8d76d28d6c
Harvey, W.R.
2ba923b7-bf60-4eda-9efa-fa55f2fc3870
Boudko, D.Y.
02ce9c4a-2862-4aa1-a21f-15273775f1bb
Moroz, L.L.
7c26e891-4e40-468e-ad2f-ec618b64700f
Linser, P.J.
30580957-e396-451c-9293-ef92ea2c6dfb
Trimarchi, J.R.
ed60c317-c345-4d45-b1bf-22196e05ff55
Smith, P.J.
003de469-9420-4f12-8f0e-8e8d76d28d6c
Harvey, W.R.
2ba923b7-bf60-4eda-9efa-fa55f2fc3870

Boudko, D.Y., Moroz, L.L., Linser, P.J., Trimarchi, J.R., Smith, P.J. and Harvey, W.R. (2001) In situ analysis of pH gradients in mosquito larvae using non-invasive, self-referencing, pH-sensitive microelectrodes. Journal of Experimental Biology, 204, part 4, 691-699. (PMID:11171351)

Record type: Article

Abstract

The alkaline environment, pH approximately 11, in the anterior midgut lumen of mosquito larvae is essential for normal nutrition and development. The mechanism of alkalization is, however, unknown. Although evidence from immunohistochemistry, electron microscopy and electrophysiology suggests that a V-ATPase is present in the basal membranes of the epithelial cells, its physiological role in the alkalization process has not been demonstrated. To investigate a possible role of the V-ATPase in lumen alkalization, pH gradients emanating from the hemolymph side of the midgut in semi-intact mosquito larvae were measured using non-invasive, self-referencing, ion-selective microelectrodes (SERIS). Large H+ concentration gradients, with highest concentrations close to the basal membrane (outward [H+] gradients), were found in the anterior midgut, whereas much smaller gradients, with concentrations lowest close to this membrane (inward [H+] gradients), were found in the gastric caeca and posterior midgut. Similar region-specific pH gradients, with consistent anterior-to-posterior profiles, were observed in individuals of two Aedes species, Aedes aegypti from semi-tropical Florida and Aedes canadensis from north-temperate Massachusetts. The gradients remained in a steady state for up to 6 h, the maximum duration of the recordings. Bafilomycin A1 (10(-5), 10(-7 )mol x l(-1)) on the hemolymph side greatly diminished the [H+] gradients in the anterior midgut but had no effect on the gradients in the gastric caecum and posterior midgut. These physiological data are consistent with the previous findings noted above. Together, they support the hypothesis that a basal, electrogenic H+ V-ATPase energizes luminal alkalization in the anterior midgut of larval mosquitoes.

Text
691.full.pdf - Version of Record
Download (258kB)

More information

Published date: February 2001
Organisations: University of Southampton

Identifiers

Local EPrints ID: 188845
URI: https://eprints.soton.ac.uk/id/eprint/188845
ISSN: 0022-0949
PURE UUID: 37ce0260-217b-433e-8878-b7e62e6a768d
ORCID for P.J. Smith: ORCID iD orcid.org/0000-0003-4400-6853

Catalogue record

Date deposited: 13 Jun 2011 12:37
Last modified: 15 Aug 2019 00:38

Export record

Contributors

Author: D.Y. Boudko
Author: L.L. Moroz
Author: P.J. Linser
Author: J.R. Trimarchi
Author: P.J. Smith ORCID iD
Author: W.R. Harvey

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×