Volume 49, Issue 6
June 1959, pages 369-427
pp 369-376 June 1959
1. Some frog’s stomach muscles and dog’s stomach muscle continuously release acetylcholine.
2. Stimulation of vagus nerve increases the release of acetylcholine.
3. After the nerve has fatigued, direct electrical stimulation releases acetylcholine; this direct stimulus is far more potent than nervous stimulation, showing that the release of acetylcholine can occur independently of nervous stimulation.
4. In dog’s stomach muscle, the release of acetylcholine continues undiminished after the nerves have fatigued. It occurs whether the nerves are further stimulated or not. This suggests that the acetylcholine released during nervous stimulation originates from the muscle. These experiments therefore throw doubt on the chemical theory of neuromuscular transmission.
pp 377-385 June 1959
A study of the blood serum proteins and lipoproteins of five species of India freshwater fish (Catla catla, Labeo rohito, Cirrhina mrigala, Labeo bata andLabeo calbasu) has been carried out, by the agar electrophoresis method. The blood protein pattern of fish is significantly different from that of other mammalian species. Though the general pattern of the five species of fish studied appear to be similar, appreciable interspecies variation is found to exist in the blood protein make-up of freshwater fishes.
pp 386-396 June 1959
Comparative efficiency of ammonium and nitrate nitrogen source, for growth of rice has been studied under solution culture technique. It is seen that:—
At moderate level of nitrogen (20 p.p.m.), ammonium and nitrate nitrogen are equally good nitrogen sources from the point of nitrogen uptake and grain yield but straw yield is higher with ammonium nitrogen.
At high nitrogen supply (100 p.p.m.), nitrate nitrogen is superior to ammonium nitrogen as the latter gives restricted root growth and disturbed nitrogen metabolism in the leaf tissue resulting in higher accumulation of soluble nitrogen to protein nitrogen.
Nitrate nitrogen is found to promote uptake of potassium, calcium, magnesium, manganese and phosphate by rice plant.
Comparatively better growth and crop yield is obtained with ammonium nitrogen given up to ear-initiation and nitrate nitrogen at later growth. Ammonium nitrogen is, therefore, suitable during vegetative stage for increasing tillering capacity, while nitrate nitrogen is preferred by the plant at the elongation and reproductive stage. It is suggested that this preference for nitrogen source is related to the oxidation reduction character of the plant root at different stages of plant growth.
Authors are indebted to Mr. R. L. M. Ghose, Director, Central Rice Research Institute, Cuttack, for his suggestion which helped improvement in the text of the paper.
pp 397-401 June 1959
pp 402-407 June 1959
Gastrulation inGeœmyda trijuga coronata andLissemys punctata granosa begins with distinctinvagination followed by a process ofinvolution andcell migration. The archenteric pouch is not co-extensive with the epiblastic embryonic shield and hence cell proliferation and migration are important factors in the formation of the primary germinal layers. The invagination of the endoderm cells is the first event in the initial process of gastrulation. It is only after the endoderm material has completely invaginated that the presumptive notochordal cells migrate backwards preceded by the prechordal plate cells. A prechordal plate is seen in the mature gastrula at the anterior end of the notochordal band in which position it lies below the anterior end of the neural plate area. The mesoderm arises by involution of cells at the lateral lips of the blastopore and also by cell proliferation from the median notochordo-endodermal band. Posteriorly mesoderm is proliferated from the primitive plate. It is possible that the mesoderm of the prechordal plate is proliferated from the primary endoderm.
pp 408-419 June 1959
The alterations in rat serum proteins resulting from (i) variations in dietary protein quality and level, (ii) minimal intakes of B vitamins and (iii) single and combined deficiencies of vitamin B12 and folic acid have been studied with egg albumin, casein and peanut protein diets at 10 and 18 per cent. protein levels.
Protein quality chiefly influences serum concentrations of albumin andα1-globulin, the effects on other fractions being variable. Protein level affects serum levels of albumin,α1-globulin andα2-globulin. The effects due to these dietary variables are interdependent.
Variations in dietary protein quality do not alter the relative distribution of serum protein fractions. Changes in protein level cause shifts in the relative distribution of globulins, the albumin-globulin ratio remaining unaltered.
The nature and extent of changes in serum protein profile due to vitamin insufficiencies or deficiencies are also influenced, qualitatively and quantitatively, by dietary amino acids. With minimal intakes of B vitamins γ-globulin is chiefly reduced, but other fractions, particularlyα1-globulin, may also be affected. In a combined deficiency of vitamin B12 and folic acid a common reduction inγ-globulin is variably attended by reductions in albumin and inα1- andβ-globulins. In single vitamin B12 deficiency, the changes are confined to albumin,α1-globulin andα2-globulin fractions, whereas single folic acid deficiency chiefly affectsγ-globulin with variable effects on albumin andβ-globulin fractions.
pp 420-427 June 1959
The multinucleate antipodal cells inLantana camara L. are described with reference to their duration. The occurrence of mitotic divisions of the antipodal nuclei is confirmed. The antipodal unit begins to degenerate after the second cell generation in endosperm.
The pattern of mature delineation of endosperm is blocked out when the endosperm is composed of three superposed cells. The micropylar cell undergoes two divisions at right angles to each other to constitute a four-celled micropylar haustorium. The chalazal cell differentiates in a similar way into the chalazal haustorium. The middle cell builds up the body of the endosperm. The four cells of the micropylar haustorium remain as such at maturity while cytomixis is accomplished in the chalazal haustorium, at later stages. The reported occurrence of an antipodal haustorium is disproved.