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First evidence of epithelial transport in tardigrades: a comparative investigation of organic anion transport.
Halberg, Kenneth Agerlin; Møbjerg, Nadja.
Afiliação
  • Halberg KA; Department of Biology, The August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark. kahalberg@bio.ku.dk
J Exp Biol ; 215(Pt 3): 497-507, 2012 Feb 01.
Article em En | MEDLINE | ID: mdl-22246258
We investigated transport of the organic anion Chlorophenol Red (CPR) in the tardigrade Halobiotus crispae using a new method for quantifying non-fluorescent dyes. We compared the results acquired from the tardigrade with CPR transport data obtained from Malpighian tubules of the desert locust Schistocerca gregaria. CPR accumulated in the midgut lumen of H. crispae, indicating that organic anion transport takes place here. Our results show that CPR transport is inhibited by the mitochondrial un-coupler DNP (1 mmol l(-1); 81% reduction), the Na(+)/K(+)-ATPase inhibitor ouabain (10 mmol l(-1); 21% reduction) and the vacuolar H(+)-ATPase inhibitor bafilomycin (5 µmol l(-1); 21% reduction), and by the organic anions PAH (10 mmol l(-1); 44% reduction) and probenecid (10 mmol l(-1); 61% reduction, concentration-dependent inhibition). Transport by locust Malpighian tubules exhibits a similar pharmacological profile, albeit with markedly higher concentrations of CPR being reached in S. gregaria. Immunolocalization of the Na(+)/K(+)-ATPase α-subunit in S. gregaria revealed that this transporter is abundantly expressed and localized to the basal cell membranes. Immunolocalization data could not be obtained from H. crispae. Our results indicate that organic anion secretion by the tardigrade midgut is transporter mediated with likely candidates for the basolateral entry step being members of the Oat and/or Oatp transporter families. From our results, we cautiously suggest that apical H(+) and possibly basal Na(+)/K(+) pumps provide the driving force for the transport; the exact coupling between electrochemical gradients generated by the pumps and transport of ions, as well as the nature of the apical exit step, are unknown. This study is, to our knowledge, the first to show active epithelial transport in tardigrades.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Transporte Biológico Ativo / ATPase Trocadora de Sódio-Potássio / Transportadores de Ânions Orgânicos / Tardígrados / Gafanhotos Limite: Animals Idioma: En Revista: J Exp Biol Ano de publicação: 2012 Tipo de documento: Article País de afiliação: Dinamarca País de publicação: Reino Unido

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Transporte Biológico Ativo / ATPase Trocadora de Sódio-Potássio / Transportadores de Ânions Orgânicos / Tardígrados / Gafanhotos Limite: Animals Idioma: En Revista: J Exp Biol Ano de publicação: 2012 Tipo de documento: Article País de afiliação: Dinamarca País de publicação: Reino Unido