Physico-chemical characterisation and molecular organisation of the collagen from the skin of an air-breathing fish (Ophiocephalus striatus).

Collagen has been prepared from the skin of an air-breathing Indian fish (Ophiocephalus striatus) by extraction with cold 0.5M acetic acid and purification by alternate precipitation with NaCl and dialysis against 0.02M Na2HPO4. The purified collagen was characterised with respect to physico-chemical properties, amino acid composition and chromatography of the denatured collagen. The fish collagen has a higher shrinkage temperature and denaturation temperature compared to that of the allied teleosts living in exclusively aquatic medium. These differences could possibly be reflections of the response to the rigours of the environment. As found for other vertebrate collagens, the fish collagen contains two kinds of single chains the α1 and α2 chains as revealed by sodium dodecyl sulphate–polyacrylamidegel electrophoresis and carboxymethylcellulose chromatography.

A comparative study of the composition of the collagens of the foot of two lamellibranch molluscs occurring in different habitats.

A comparative study of the collagen of the foot of Lamellidens Sp. and that of the unmodified part of the foot in Mytilus edulis shows marked differences in physical properties, amino acid composition and in the degree of stabilization. But both conform to type I collagen of vertebrates. In these respects, the latter shows agreement with the features characteristic of byssus collagen, which is highly crosslinked, involving dimers and trimers of tyrosine. It is suggested that such differences may reflect the different functions of the organs concerned, the foot of Lamellidens being a locomotary organ of the animal, while the foot of Mytilus edulis is modified for anchorage of the animal. The vertigial part though not morphologically modified shows the essential compositional characteristics of the byssus being a mere remanant of it.

HETEROGENEITY OF TRACHEAL EPITHELIAL GOBLET CELLS OF MONKEY / 解剖学报

The reactions of 8 lectins with tracheal epithelial goblet cells of Rhesus monkeyshowed the heterogeneity of the cells.The heterogeneity appeared on the differentcomposition of sugar chains in the secretory mucin.The mucin of all goblet cellscontained unequal amount of terminal ?-D-galactose,?-D-mannose and sialic acid aswell as pre-terminal-?-D-galactose and/or ?-D-galactose-(1→3)-N-acetylgalactosa-mine.Only part of goblet cells had variable amount of ?-L-fucose in the secretorymucin.The compositions of sugar chains of the secretory mucin between monkeyand human have significant difference.