title: X-ray microanalysis of the filter chamber of the cicada, Cyclochila australasiae Don. A water-shunting epithelial complex.
abstract: X-ray microanalysis of frozen-hydrated specimens of the cicada filter chamber shows that there are concentration changes in K+ and Cl- in the various compartments of the filter chamber from feeding to non-feeding states. These changes are consistent with an osmotic transfer of water between the anterior midgut and the posterior midgut and Malpighian tubules. K+ and Cl- account for a large proportion of the osmotically active solutes in these compartments, and it is suggested that the osmotic gradients are generated by secretion of K+ and Cl- into the posterior midgut and Malpighian tubule lumina. Analysis of freeze-substituted sections of filter chamber supports the analysis of frozen-hydrated specimens and indicates that Na+ may also be secreted into the posterior midgut and the Malpighian tubules. The system functions as a water-shunting complex.
mesh_terms: D000818:Animals; D001834:Body Water / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism; D004064:Digestive System / Q000033:anatomy & histology; D004068:Digestive System Physiological Phenomena; D004577:Electron Probe Microanalysis; D004848:Epithelium / Q000378:metabolism; D005615:Freezing; D007313:Insecta / Q000033:anatomy & histology* / Q000502:physiology; D009997:Osmotic Pressure; D011188:Potassium / Q000378:metabolism
chemical_list: D002712:Chlorides; D011188:Potassium