Glycosaminoglycan involved in the cation-induced change of body wall structure of sea cucumber Stichopus japonicus.
The body wall of sea cucumber Stichopus japonicus was treated with various concentrations of several cations, and examined for changes in toughness, taking punch force as parameter. Toughness of the body wall tended to decrease with increasing concentration of each cation, but in different modes depending mainly upon the valency of cation: e.g., the body wall completely lost toughness in 0.3 M Na+ or 0.4 M K+, whereas it retained more than half the initial toughness even in 0.4 M Ca2+ or Mg2+. Glycosaminoglycan (GAG) from the body wall was dissolved in water, and examined for viscosity changes as caused by those cations. Specific viscosity (eta sp) decreased from 0.71 (without cation) to 0.47-0.57 in the presence of 0.1 M monovalent and divalent cations. At 0.4 M, monovalent cations reduced eta sp to 0.38-0.46, but divalent cations increased eta sp to 0.56-0.63. Electron microscopy demonstrated that GAG matrix was clearly observed in the absence of cation, but disappeared in 0.4 M NaCl, forming wide free spaces in the body wall. These results all suggested that GAG is closely involved in the change of toughness of sea cucumber body wall.
Kariya
Y
Y
Laboratory of Marine Biochemistry, Faculty of Agriculture, University of Tokyo, Japan.
Watabe
S
S
Ochiai
Y
Y
Murata
K
K
Hashimoto
K
K
D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology*; D002414:Cations, Monovalent / Q000494:pharmacology*; D006025:Glycosaminoglycans / Q000032:analysis / Q000494:pharmacology*; D008854:Microscopy, Electron; D011506:Proteins / Q000032:analysis; D012616:Sea Cucumbers / Q000032:analysis / Q000502:physiology* / Q000648:ultrastructure; D012996:Solutions; D014783:Viscosity
D002413:Cations, Divalent; D002414:Cations, Monovalent; D006025:Glycosaminoglycans; D011506:Proteins; D012996:Solutions