title: Localization of ion-regulatory epithelia in embryos and hatchlings of two cephalopods.
abstract: The tissue distribution and ontogeny of Na(+)/K(+)-ATPase has been examined as an indicator for ion-regulatory epithelia in whole animal sections of embryos and hatchlings of two cephalopod species: the squid Loligo vulgaris and the cuttlefish Sepia officinalis. This is the first report of the immunohistochemical localization of cephalopod Na(+)/K(+)-ATPase with the polyclonal antibody alpha (H-300) raised against the human alpha1-subunit of Na(+)/K(+)-ATPase. Na(+)/K(+)-ATPase immunoreactivity was observed in several tissues (gills, pancreatic appendages, nerves), exclusively located in baso-lateral membranes lining blood sinuses. Furthermore, large single cells in the gill of adult L. vulgaris specimens closely resembled Na(+)/K(+)-ATPase-rich cells described in fish. Immunohistochemical observations indicated that the amount and distribution of Na(+)/K(+)-ATPase in late cuttlefish embryos was similar to that found in juvenile and adult stages. The ion-regulatory epithelia (e.g., gills, excretory organs) of the squid embryos and paralarvae exhibited less differentiation than adults. Na(+)/K(+)-ATPase activities for whole animals were higher in hatchlings of S. officinalis (157.0 +/- 32.4 micromol g (FM) (-1) h(-1)) than in those of L. vulgaris (31.8 +/- 3.3 micromol g (FM) (-1) h(-1)). S. officinalis gills and pancreatic appendages achieved activities of 94.8 +/- 18.5 and 421.8 +/- 102.3 micromol(ATP) g (FM) (-1) h(-1), respectively. High concentrations of Na(+)/K(+)-ATPase in late cephalopod embryos might be important in coping with the challenging abiotic conditions (low pH, high pCO(2)) that these organisms encounter inside their eggs. Our results also suggest a higher sensitivity of squid vs. cuttlefish embryos to environmental acid-base disturbances.
authors.affiliation: Leibniz Institute of Marine Sciences, Kiel, Germany. mhu@ifm-geomar.de
authors.forename: Marian Y
authors.initials: MY
authors.lastname: Hu
authors.forename: Elliott
authors.initials: E
authors.lastname: Sucré
authors.forename: Mireille
authors.initials: M
authors.lastname: Charmantier-Daures
authors.forename: Guy
authors.initials: G
authors.lastname: Charmantier
authors.forename: Magnus
authors.initials: M
authors.lastname: Lucassen
authors.forename: Nina
authors.initials: N
authors.lastname: Himmerkus
authors.forename: Frank
authors.initials: F
authors.lastname: Melzner
mesh_terms: D000818:Animals; D000906:Antibodies; D015153:Blotting, Western; D049830:Cephalopoda / Q000033:anatomy & histology / Q000196:embryology* / Q000201:enzymology; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D004848:Epithelium / Q000201:enzymology / Q000378:metabolism*; D005880:Gills / Q000166:cytology / Q000201:enzymology; D007150:Immunohistochemistry; D007477:Ions / Q000378:metabolism; D009928:Organ Specificity; D010179:Pancreas / Q000166:cytology / Q000201:enzymology; D021381:Protein Transport; D012867:Skin / Q000166:cytology / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D000906:Antibodies; D007477:Ions; D000254:Sodium-Potassium-Exchanging ATPase