Immunocytochemical Localization of Na⁺,K⁺-ATPase in the Calcium-transporting Sternal Epithelium of the Terrestrial Isopod Porcellio scaber L. (Crustacea)

Abstract

SUMMARYTerrestrial isopods store large amounts of calcium carbonate between the epithelium and the old cuticle of the first four anterior sternites before molt. During the formation of these sternal CaCO 3 deposits, large amounts of calcium are transported across the anterior sternal epithelium from the base to the apical side of the integument, and in the reverse direction during resorption of the deposit. A monoclonal antibody against the avian ␣ -subunit of Na ϩ ,K ϩ -ATPase was used to localize Na ϩ ,K ϩ -ATPase in the anterior and the posterior sternal epithelium of Porcellio scaber . Semithin cryosections 0.5 m thick were used for immunofluorescence microscopy and ultrathin cryosections for immunogold electron microscopy. The Na ϩ ,K ϩ -ATPase was localized in the basolateral plasma membrane of the posterior and anterior sternal epithelium. The apical plasma membrane, including cytoplasmic extensions into the newly secreted cuticle, was virtually devoid of the enzyme. This pattern of immunolocalization was not affected by the direction of transepithelial calcium transport associated with the deposition and resorption phases of the molt cycle.

Expression and polarity reversal of V-type H+-ATPase during the mineralization–demineralization cycle in Porcellio scabersternal epithelial cells

“…The immunolocalization at the basolateral side of the epithelial cells in the late premolt stage corresponds well with the spatial distribution of the basolateral plasma membrane, which increases by an elaborate system of invaginations (Figs·5E,F and 6A), as shown previously using lanthanum as an extracellular marker and immunocytochemical localization of the Na + /K + -ATPase in the basolateral membrane (Ziegler, 1996(Ziegler, , 1997a. Areas within the cytoplasm that do not include invaginations are virtually devoid of VHA.…”

“…This is the case in epithelia with little activity of the classical energizer of animal plasma membranes, the Na + /K + -ATPase, as in lepidopteran midgut (Jungreis and Vaughan, 1977;Wieczorek et al, 1999a) or malpighian tubules (Weng et al, 2003). In the ASE of P. scaber immunocytochemical localization of the Na + /K + -ATPase indicates a high abundance of the pump within the basolateral membrane (Ziegler, 1997a), arguing against an energization by the VHA. However, as pointed out by Wieczorek et al (1999a), some epithelia energize the basolateral plasma membrane by the Na + /K + -ATPase and the apical membrane by a VHA.…”

“…Micrographs were taken using a Spot CCD camera (Visitron, Puchheim, Germany). The distribution of the basolateral plasma membrane was labeled using the mouse monoclonal anti Na + /K-ATPase antibody (α5), and FITC-conjugated antimouse IgG (Sigma) following the procedure described previously (Ziegler, 1997a).…”

Immunolocalization of Na+,K+-ATPase in the branchial cavity during the early development of the crayfish Astacus leptodactylus (Crustacea, Decapoda)

“…The mouse monoclonal IgGα 5 , raised against the avian α-subunit of the Na + ,K + -ATPase, recognizes three α isoforms (α1, α2, α3) and cross-reacts with the α-subunits of the Na + ,K + -ATPase of several fish and insect epithelia (Lebowitz et al, 1989;Baumann and Takeyasu, 1993;Baumann et al, 1994;Just and Waltz, 1994;Witters et al, 1996). In crustaceans, this antibody specifically recognizes a single band of about 90-110 kD, as observed in the terrestrial isopod Porcellio scaber (Ziegler, 1997) and in the European decapod lobster Homarus gammarus (Lignot et al, 1999;Lignot and Charmantier, 2001). In the present immunocytochemical study, the mouse monoclonal IgGα 5 appears to recognizes its epitope in the branchial cavity of the developing freshwater crayfish, Astacus leptodactylus.…”

“…The technique for the immunocytochemical demonstration of Na + ,K + -ATPase in epithelial cells was similar to the procedures of Ziegler (1997), Lignot et al (1999) …”