Nidamental Gland Mucosubstance from the Squid Illex argentinus: Salt-soluble Component as a Mucin Complex

Abstract

Spawned eggs of the squid Illex argentinus are assumed to be wrapped up in fragile gels which are largely derived from the mucosubstance of nidamental glands. This mucosubstance is known to contain mucin-type glycoprotein as a main constituent. In this study, the soluble components of mucosubstance were prepared by sequential extraction with deionized water and 0.6 M NaCl, pH 7.2. The water-soluble component was poor in amino sugars and exhibited a low viscosity in solution, indicating the virtual absence of mucin. On the other hand, the salt-soluble component was relatively rich in amino sugars and had a high intrinsic viscosity of 10.0 dl/g. Moreover, sedimentation velocity analyses revealed that it comprised only a simple, sharp peak having a molecular weight of about 6.6 × 106. When treated with 0.4 N NaOH, about 30% of the salt-soluble component was precipitated with 50% ethanol and identified as mucin. From these results, the salt-soluble component of mucosubstance was found to be a mucin complex which presumably exists in the gel structure of egg mass. © 1995, The Japanese Society of Fisheries Science. All rights reserved.