title: Nematodirus battus: permeability changes, calcium binding, and phosphorylation of the eggshell during hatching.
abstract: Eggshells of Nematodirus battus leaked trehalose 4 hr after being stimulated to hatch, and became permeable to trypan blue at their poles; 80% of eggs were stained blue 24 hr later. Exogenous application of ruthenium red significantly inhibited chill- and sodium fluoride-stimulated hatching, 50% hatch inhibition occurring in 44.67 +/- 2.2 and 8.5 +/- 1.5 microM, respectively. Lanthanum chloride, however, was not as inhibitory as ruthenium red on fluoride-stimulated hatching, 50% occurring at 31.60 +/- 1.25 microM. A Scatchard plot of the competitive binding of ruthenium red to eggshells demonstrated a high-affinity binding site for calcium, KCa' = 1.92 microM and a second, low-affinity site, KCa" = 1169.60 microM. Ruthenium red binding was significantly reduced by several enzymes, e.g., EGTA-buffered trypsin reduced binding by 73%. Radioiodinated concanavalin A also bound competitively to the eggshells in the presence of alpha-D-glucosyl-alpha-D-glucopyranoside and alpha-methyl-D-mannopyranoside. Eggshells incorporated phosphorus-32 from ATP after chilling or on exposure to sodium fluoride; gel filtration of solubilized homogenates of these samples showed that two proteins were radiolabelled with molecular weights of 38 X 10(3) and 8 X 10(3) Da, respectively. This phosphorylation was inhibited by N-ethylmaleimide, which also prevented hatching.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism*; D003208:Concanavalin A / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology; D005260:Female; D006863:Hydrogen-Ion Concentration; D010063:Ovum / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010539:Permeability; D010766:Phosphorylation; D012430:Ruthenium Red / Q000378:metabolism / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology; D014251:Trichostrongyloidea / Q000502:physiology*
chemical_list: D003208:Concanavalin A; D012430:Ruthenium Red; D000255:Adenosine Triphosphate; D012969:Sodium Fluoride; D005033:Ethylmaleimide; D002118:Calcium