• A L Paulpandian

      Articles written in Proceedings – Animal Sciences

    • Quantitative analysis of carbohydrases in the crystalline style of some intertidal bivalve molluscs

      P Shahul Hameed A L Paulpandian

      More Details Abstract Fulltext PDF

      Amylase activity in different pH ranging from 3·6 to 8·0 and activity of sucrose, maltose, trehalase, raffinase, lactase, glycogenase, pectinase, chitinase, carboxy methyl cellulase and cellulase at their respective optimum pH were quantitatively estimated in the crystalline style of intertidal bivalves,Crassostrea madrasensis, Meretrix meretrix, Meretrix casta, Katelysia opima andDonax cuneatus. Amylase was the most active among all enzymes tested. A maximum activity of 137·5 μg/mg/h was recorded in the style ofKatelysia opima while the activity was minimal inDonax cuneatus (39·3 μg/mg/h). Two pH optima were recorded for style amylase ofCrassostrea madrasensis (6·0 and 6·8) andKatelysia opima (5·6 and 6·8). But the activity was higher at higher optimum pH. The enzymes hydrolysing oligosaccharides were weak in most cases or absent. The enzymes acting on reserve polysaccharides such as amylase and glycogenase showed maximum activity in the species tested. However the activity of enzymes degrading structural polysaccharides such as cellulase, carboxy methyl cellulase, pectinase and chitinase was either at a low level or absent. The role of the style enzymes in the extracellular digestion of bivalves is discussed.

    • Feeding and extracellular digestive rhythms in some intertidal bivalve molluscs

      P Shahul Hameed A L Paulpandian

      More Details Abstract Fulltext PDF

      The tidal rhythms for changes in morphology, length, dry weight and protein content of the crystalline style are studied in two venerid clams,Meretrix meretrix andKatelysia opima and in a donacid clam,Donax cuneatus. In the two venerid clams the style is housed in a sac conjoined with midgut and there is a tidal rhythm of feeding and extracellular digestion involving a partial dissolution of the style in the ebb tide and reformation in flood tide. But in the donacid clam where the style sac is completely separated from midgut, no detectable changes in the style parameters are recorded during a tidal cycle. However, the rhythmicity in feeding activity is indicated, by the presence of ‘mudcap’ and food particles in the style during flood tide and their subsequent absence during ebb tide. Hence the tidal rhythm of feeding and digestion inDonax cuneatus may be without corresponding changes in the crystalline style. Also this study throws light on the mode of style dissolution.

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