Volume 47, Issue 4
April 1958, pages 189-262
pp 189-192 April 1958
The activities of the enzyme systems for serine decarboxylation, ethanolamine to serine conversion, serine synthesis from glycine and serine deamination, have been followed with cell fractions obtained by differential centrifugation.
Serine decarboxylation, ethanolamine to serine conversion and glycine to serine conversion are associated largely with the mitochondria, while serine deamination is maximum in the nuclear fraction.
pp 193-201 April 1958
A marked decrease in the amino acid composition of rat liver proteins in vitamin B6 and folic acid deficiency but not in biotin deficiency is reported.
pp 202-209 April 1958
The distribution of non-protein nitrogen in some marine fishes, crustacea and molluscs was studied. The non-protein nitrogen constituted about 10% of the total nitrogen in the teleosts, 20% in the crustaceans and molluscs and over 30% in the elasmobranchs. High levels of freea-amino acid nitrogen (300 mg. N/100 g. of wet muscle) were found in the crustaceans and molluscs unlike in the fishes (20 to 40 mg. N/100 g. of wet muscle). The trimethylamine oxide content varied greatly in the fishes, etc. The significance of these results from the comparative aspect and in fish processing is discussed.
pp 210-224 April 1958
pp 225-232 April 1958
1. The series of changes prior to the dissolution of the vacuole on stimulation with fresh medium has been followed up under dark ground and phase contrast in individual yeast cells.
2. Under dark ground the luminous vacuolar contour disappears from view between 35–60 minutes and the cytoplasm appears free of luminous structures between 75–120 minutes.
3. Under phase contrast the vacuole gradually decreases in size and often breaks up into a number of smaller ones prior to dissolution. The cell appears bereft of any visible inclusions between 100–160 minutes. The time taken by the vacuoles and grains to disappear from view is shorter when the cells are stimulated in a test-tube.
4. The impermanence of the vacuole renders its identification as the nucleus of yeast problematical.
pp 233-251 April 1958
On the basis of histological and experimental studies involving blood transfusions, injection of ovarian extracts, and transplantation of neurosecretory cells, it is concluded that there is an endocrine basis for oviposition in the insectIphita limbata Stal. (Pyrrhocoridæ: Hemiptera), a common plant bug of South India. Oviposition is brought about in the gravid female by a hormone-complex involving the interaction between the ovary and the neurosecretory system. It is tentatively postulated that it probably works out as follows:
Stainable neurosecretory matter from the cells of the pars intercerebralis of the brain passes along the axons of the allatic nerve to the corpus allatum. This stimulates the gland which consequently begins to enlarge and initiates egg-growth by deposition of yolk. When eggs become full grown and ripe,i.e., when the animal becomes gravid, the ovarian wall releases a substance into the blood which may be presumed to exert a dual action on the neurosecretory system. Evidences show that the supply of visible, stainable, neurosecretory colloids to the corpus allatum is reduced or inhibited, which may result in an inactivation of the gland and stops further elaboration of yolk in the eggs. At the same time, the blood-borne factor influences the cells of the pars intercerebralis to release their colloids into blood. This release of neurosecretory matter may have a role in inducing oviposition by promoting oviducal contractions.
pp 252-262 April 1958
An intergeneric hybrid betweenC. cajan (Linn.) Millsp. (2n=22)×A. lineata, W. & A. (2n=22) was obtained. The morphology of the somatic chromosomes of the parents and the F1 was studied. It was observed that there was difference in the chromosome morphology of the two species. Some meiotic irregularities were observed in the F1 which showed only partial fertility. It is suggested that the sterility of F1 is due to the structural differences in the chromosome of the two parents. The homology between the chromosome complements of the two parents suggests close relationship between them.