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41.
H Papkoff H M Murthy J F Roser 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1984,177(1):42-46
The tyrosine residues of equine chorionic gonadotropin have been nitrated with tetranitromethane and the resulting effects on the biological and immunological activities of the hormone studied. All of the tyrosine residues in equine chorionic gonadotropin were found to react with tetranitromethane when a 100-fold molar excess of reagent was used or with an 8.6 molar excess in the presence of 5 M guanidine hydrochloride. Complete nitration abolished the biological activities and decreased the immunological activity of the hormone. The nitration of one tyrosine residue resulted in the loss of 70% of the LH activity of equine chorionic gonadotropin; the FSH activity declined in a similar fashion. Maximal nitration resulted in the loss of about 50% of the immunological activity of the native hormone. Nitrated derivatives of equine chorionic gonadotropin were unable to compete with the native hormone in the rat Leydig cell assay for LH. The results indicate that the tyrosine residues of equine chorionic gonadotropin play an important role in the manifestation of both the FSH and LH activity of the hormone. 相似文献
42.
A procedure has been described for the quantitative isolation of [14C]-mevalonic acid from reaction mixtures used for the assay of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. It consists of absorbing the reaction mixtures on Whatman No. 4 filter-paper supports and concentrating the radioactive substrate and the product within a 2-mm2 area of the paper by two-dimensional elution with nonpolar solvents. This procedure simultaneously results in desalting of the reaction mixture, thus facilitating an excellent thin-layer chromatographic separation of mevalonolactone uncontaminated by the radioactive substrate. Among other advantages of the method are (a) quantitative extraction of mevalonolactone, thus avoiding the necessity of using an internal standard; (b) possibility of simultaneous processing of a large number of samples with the elution being carried out overnight without frequent supervision; (c) simplicity of the technical operations involved; and (d) inexpensiveness of the materials needed for analysis. 相似文献
43.
Hexokinase is present in the tissues in four isoenzymic forms. Cerebral tissue contains predominantly Type I hexokinase which
is believed to be insulin-insensitive. In cerebral tissue about 60 to 70% of the hexokinase is bound to the particulate fraction.
The changes in the distribution of hexokinase Type I and Type II together with the bound and free hexokinase have been studied
in control, diabetic and diabetic animals treated with insulin. The results indicate that the presence of insulin is essential
for the normal binding of the hexokinase to the particulate fraction. In heart tissue, Type II hexokinase bound to the pellet
shows a significant decrease in diabetes, which is reversed on insulin administration. 相似文献
44.
Flat bones of human skeleton were subjected to dynamic indentation with ball indenters. The impacted surface was studied under
high magnification and also by using the technique of multiple beam interferometry. The impulse caused the pile up of material
at a little distance from the edge of the indent. The diameter of indent is found to increase as fourth root of the energy
of impact. Bone structure also has the tendency to minimize the damage caused by external forces. There was about 90% recovery
in deformation in the depth of indents due to internal stresses created inside the bone by the impact. 相似文献
45.
T. Srinivas M. K. Bhashyam Nagin Chand Sila Bhattacharya S. Sreedhara Murthy H. V. Narasimha 《Economic botany》1991,45(4):503-510
Twenty varieties of maize (Zea mays, Poaceae) were studied through 11 attributes in three to seven randomly selected plants of each variety with a view to understanding the effect of cob characters on technologically desirable grain qualities. Canonical discriminant analysis showed thatproductivity (determined by total grain weight/cob, cob diameter and average grain weight) was the most discriminating among varieties followed by round grains fraction (represented by whole top and middle flat grains, number of rows and grain count/surface area), middle flat grains (composed of middle flat grains and grain count/surface area) and shape of the cob (determined by shape index, total grain weight/cob and cob diameter), which accounted for 35.1, 18.3, 12.2, and 9.8% of the total variance, respectively. In the light of these results, tentative norms have been suggested to evolve maize varieties of superior technological properties and yet retain high productivity. A cylindrical cob of large diameter with highest number of grains/area and smallest possible number of rows together constituted an ideal combination to achieve the objectives. Such possibilities in the light of available information are discussed. 相似文献
46.
Murthy PP Pliska-Matyshak G Keranen LM Lam P Mueller HH Bhuvarahamurthy N 《Plant physiology》1992,98(4):1498-1501
The structure of phosphatidylinositol in barley (Hordeum vulgare) aleurone layers was investigated by chemical degradation. In vivo myo-[2-3H]inositol-labeled phosphatidylinositol was first converted to glycerophosphoinositol and, subsequently, after removal of the glycerol moiety, to inositol monophosphate. Here, we present data that show that, in addition to the commonly occurring 1,2-diacylglycero-3-(d-myo-inositol-1-phosphate), barley aleurone cells contain a novel second isomer of phosphatidylinositol that differs in structure of the head group. 相似文献
47.
D S Murthy T S Sundareshan T I Farag S A al-Awadi S A al-Othman 《Indian journal of experimental biology》1990,28(6):511-515
The frequency and types of acrocentric chromosome association were quantitatively analysed in a Down syndrome child with unusual karyotype, 46, XX, -14, -22, t dic (14p;22p), +21, 21S+. Father and 4 sibs were heterozygous carriers for t dic (14p;22p). The variant 21S+ was inherited from the mother. The occurrence of translocation and trisomy in the same individual is extremely rare. Acrocentric chromosome association was analysed in this interesting family to understand the interrelationship of acrocentric chromosome association, Robertsonian translocation and heteromorphism, as possible predisposing factors for nondisjunction. Our findings suggest that acrocentric chromosome association is a heritable and nonrandom phenomenon. Heterozygous carriers for translocations and variants are likely to be at increased risk of nondisjunction. Long term family studies will enable to ascertain the causal-relationship of these factors more precisely. 相似文献
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