Volume 78, Issue 3
September 1973, pages 89-141
pp 89-102 September 1973
The soluble and insoluble proteins of the different tissues of the crab vary depending upon the salinity of the medium and reach an acclimated state within twenty days. The two fractions show a general decrease in various salinities. The temporal changes are minimal in muscle, maximum in hepatopancreas and intermediate in gill and heart. The percent decrease in protein content on salinity adaptation is maximum in hepatopancreas and heart, intermediate in gill and least in muscle. In any tissue, the decrease on adaptation is minimum in 50% and 75% S.W. and greater on either side of this range.
From the evidence available in the present investigation and the literature, it is suggested that the proteins also might take part in the isosmotic regulation. The proteins might degrade and contribute to the amino acid pool size in supranormal salinities and might be catabolised and utilised for the release of energy in subnormal salinities. Moreover, it seems that the role of proteins in osmotic regulation depends more upon the osmotic gradient between the body fluid and the medium rather than merely the salinity of the medium. High protein content in the fresh water, in spite of steep osmotic gradient, is assumed to be due to some homeostatic mechanisms.
pp 103-118 September 1973
Protein degradation and14C amino-acid incorporation rates in the foot muscle proteins of the pond snail,Pila globosa were studied with reference to aestivation. Lysosomal enzymes like: cathepsin, acid phosphatase except β-glucoronidase showed a decrease in activity on aestivation. Cathepsin activity showed an elevated temperature optimum on aestivation. Decreased proteolysis and autolysis on aestivation indicated a lowered turnover of proteins. To test this14C amino-acid incorporation rates were examined. Total proteins, myosin, actin, actomyosin, and tropomyosin did not exhibit any change in their incorporation rates. Sarcoplasmic proteins and collagen fraction decreased significantly in contrast to paramyosin on aestivation. It was concluded that aestivation resulted in changes in heterogeneous turnover of certain protein molecules.
pp 119-129 September 1973
1. A detailed account of the enzymes in the hepatopancreas inCaridina weberi is given.
2. The carbohydrases present include amylase, glycogenase, maltase, lactase and sucrase while raffinase and cellulase are absent. The optimum pH is 6·8 for the enzyme amylase. The enzyme gets destroyed completely between 65 and 70° C. The optimum pH for digestion of glycogen is 7·0 and the enzyme is destroyed between 68 and 71° C.
3. Lipolytic enzyme ofCaridina is rather weak. However, it digests amyl acetate, olive oil and lecithin. The optimum pH for the lipase is 7·4. The enzyme gets destroyed between 70 and 75° C.
4. The proteolytic enzyme ofCaridina is slightly weak. It acts on different types of proteins like gelatine, fibrin, peptone and casein. The action of the enzyme is maximum in an alkaline medium (pH 7·4–7·8) and it is completely destroyed between 65 and 70°C.
pp 130-141 September 1973
Morphological and anatomical peculiarities of little leaf symptoms in eight species of flowering plants belonging to six families were studied. Of these, two were described under spike diseases by earlier authors. In all the species studied, the origin of the little leaf was in shoots produced as a result of pathogenesis. This usually involved the activation of dormant axillary buds on old woody parts of the stems. The thickness of the little leaves was highly reduced with a corresponding reduction in the length of the palisade cells and decrease in number of spongy layers. There was a general lowering in the number of stomata per unit area in the little leaves even though there was no difference in the size of the stomata. The distribution of special cells containing secondary metabolic products was much restricted in the little leaf.