title: Slc4-like anion transporters of the larval mosquito alimentary canal.
abstract: Mosquito larvae exhibit luminal pH extremes along the axial length of their alimentary canal that range from very alkaline (pH>10) in the anterior midgut to slightly acid in the hindgut. The principal buffer in the system is thought to be bicarbonate and/or carbonate, because the lumen is known to contain high levels of bicarbonate/carbonate and is surrounded by various epithelial cell types which express a variety of carbonic anhydrases. However, the precise mechanisms responsible for the transport of bicarbonate/carbonate into and out of the lumen are unclear. In the present study, we test the hypothesis that SLC4-like anion transporters play a role in bicarbonate/carbonate accumulation in the larval mosquito alimentary canal. Molecular, physiological and immnuohistochemical characterizations of Slc4-like transporters in the gut of larval mosquitoes (Aedes aegypti and Anopheles gambiae) demonstrate the presence of both a Na(+)-independent chloride/bicarbonate anion exchanger (AE) as well as a Na(+)-dependent anion exchanger (NDAE). Notably, immunolocalization experiments in Malpighian tubules show that the two proteins can be located in the same tissue, but to different cell types. Immunolabeling experiments in the gastric caecae show that the two proteins can be found in the same cells, but on opposite sides (basal vs. apical). In summary, our results indicate that the alimentary canal of larval mosquitoes exhibits robust expression of two SLC4-like transporters in locations that are consistent with a role in the regulation of luminal pH. The precise physiological contributions of each transporter remain to be determined.
authors.affiliation: University of Florida, Whitney Laboratory, St. Augustine, FL 32086, USA. pjl@whitney.ufl.edu
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Linser
authors.forename: Marco
authors.initials: M
authors.lastname: Neira Oviedo
authors.forename: Taku
authors.initials: T
authors.lastname: Hirata
authors.forename: Theresa J
authors.initials: TJ
authors.lastname: Seron
authors.forename: Kristin E
authors.initials: KE
authors.lastname: Smith
authors.forename: Peter M
authors.initials: PM
authors.lastname: Piermarini
authors.forename: Michael F
authors.initials: MF
authors.lastname: Romero
mesh_terms: D000330:Aedes / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D000852:Anopheles / Q000235:genetics / Q000378:metabolism*; D027963:Chloride-Bicarbonate Antiporters / Q000235:genetics / Q000378:metabolism*; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism; D007814:Larva / Q000378:metabolism; D008969:Molecular Sequence Data; D014981:Xenopus
chemical_list: D027321:Anion Transport Proteins; D027963:Chloride-Bicarbonate Antiporters