QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Weng, X.-H. Articles by Beyenbach, K. W. Search for Related Content PubMed PubMed Citation Articles by Weng, X.-H. Articles by Beyenbach, K. W.

The V-type H⁺-ATPase in Malpighian tubules of Aedes aegypti: localization and activity

Xing-He Weng¹, Markus Huss², Helmut Wieczorek² and Klaus W. Beyenbach^1,*

¹ Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
² Department of Biology, University of Osnabrück, D-49019 Osnabrück, Germany

View larger version (54K): [in a new window]   Fig. 1. Molecular identification of the V-type H+-ATPase in Malpighian tubules of the yellow fever mosquito. (A) SDS–PAGE: lane 1, standard molecular mass proteins; lane 2, holoenzyme of the V-type H+-ATPase of Manduca sexta; lane 3, crude tubule extract of Malpighian tubules of Aedes aegypti. (B) Western blot: antibodies raised against the V-type H+-ATPase of Manduca sexta recognized similar proteins in extracts of Malpighian tubules of Aedes aegypti. Lanes 1, 3 and 5 are the Manduca holoenzyme, and lanes 2, 4 and 6 are the crude extracts of Aedes Malpighian tubules. Ab 353-2, Ab 488-1 and Ab C23 are antibodies against the V1 complex, C subunit and B subunit of the proton pump, respectively.

View larger version (54K): [in a new window]   Fig. 2. Immunolocalization of the V-type H+-ATPase in Malpighian tubules of Aedes aegypti. Paraffin sections of mosquito Malpighian tubules were labeled with a polyclonal antibody specific to the 56 kDa B subunit of the V-type H+-ATPase (see Fig. 1B). (A) Paraffin section labeled with preimmuno-serum as a negative control. (B) Paraffin section labeled with C23 polyclonal antibody; sc, stellate cell. Scale bar, 100 µm. The inset section illustrates stellate cells without staining. Arrowheads point to small stellate cells without a prominent brush border. Scale bar, 200 µm.

View larger version (16K): [in a new window]   Fig. 3. ATPase activities in crude extracts of Malpighian tubules of Aedes aegypti. The V-type H+-ATPase activity was measured as the bafilomycin- and NO3--sensitive ATPase activity. The Na+/K+-ATPase activity was measured as the ouabain- and vanadate-sensitive ATPase activity. The following inhibitor concentrations were used: bafilomycin A1, 0.025 mmol l-1; nitrate, 100 mmol l-1; ouabain, 1 mmol l-1; vanadate, 0.1 mmol l-1. Asterisks represent P<0.01. The number of determinations is shown in parentheses.

View larger version (36K): [in a new window]   Fig. 4. Models of transepithelial NaCl and KCl secretion across Malpighian tubules of the yellow fever mosquito. (A) Molecular model of transcellular Na+ and K+ secretion and paracellular Cl- secretion. (B) Electrical equivalent circuit of transepithelial electrolyte secretion. Na+ and K+ are actively transported through principal cells, and Cl- is passively transported from hemolymph to tubule lumen through the shunt pathway. E, electromotive force; V, voltage; R, resistance; t, transepithelial; bl, basolateral membrane; a, apical membrane; sh, shunt. Reproduced with permission from Beyenbach (2001).