• Volume 13, Issue 2

      June 1988,   pages  105-214

    • Effect of luteinizing hormone releasing hormone analogues on testosterone metabolismin vitro — A study with mature rat ventral prostates

      A Maitra R Joseph A R Sheth N A Sheth J Joseph

      More Details Abstract Fulltext PDF

      The effects of two luteinizing hormone releasing hormone analogues (a superagonist and an antagonist) on the conversion of testosterone to dihydrotestosterone in homogenates prepared from adult rat ventral prostates were studied. At higher doses, the superagonist showed a significant dose-dependent inhibition of the conversion of testosterone to dihydrotestosterone. In comparison, the antagonist showed only a marginally inhibitory trend. The implications of these observed effects vis-a-vis the use of the analogues in the endocrine management of prostatic cancer have been discussed.

    • Keratinization of rat vaginal epithelium. II. Immunofluorescence study on keratin filaments in cycling and estrogen primed rats

      S Vijayasaradhi P D Gupta

      More Details Abstract Fulltext PDF

      Rat vaginal epithelial layers from animals in different phases of the estrous cycle showed positive immunofluorescence when treated with either monoclonal antibody to intermediate filaments or immunoglobulin G fraction of antiserum raised against epidermal keratin filaments. During estrus, the intensity of fluorescence observed was maximum in the keratinized cellular layers. In estradiol-primed immature and ovariectomized rats the maximum fluorescence intensity was observed in the layers immediately lining the lumen. However, basal layers in ovariectomized rats also showed some fluorescence. Data presented in this communication indicate that the abundance of keratin filaments in vaginal epithelial cells can be modulated by altering the level of estradiol in the system.

    • Glycogen metabolism in human fetal testes

      K Misra Datta J Dasgupta T Sengupta S De Sengupta

      More Details Abstract Fulltext PDF

      The ontogeny of glycogen synthetase, glycogen Phosphorylase and α-D-glucosidase, enzymes which are associated with glycogen metabolism and glycogen level has been studied in human fetal testes of gestational age ranging from 14–32 weeks. Glycogen synthetase activity reaches the peak value at 17–20 weeks of gestation, thereafter it decreases. α-D-Glucosidase activity increases with the advancement of pregnancy up to 28 weeks of gestation decreasing thereafter very rapidly. Phosphorylase activity remains more or less constant throughout gestation. The maximum increase in glycogen content at early stages of gestation (17–20 weeks) and gradual reduction with the advancement of pregnancy are correlated with histochemical observation by the periodic acid-Schiff technique.

    • Interaction of lanthanum chloride with human erythrocyte membrane in relation to acetylcholinesterase activity

      Sunil Mukhopadhyay Sila Mukhopadhyay Dilip K Bhattacharyya Gora Chand Chatterjee

      More Details Abstract Fulltext PDF

      Lanthanum chloride (1 mM) inhibits the activity of acetylcholinesterasein vitro in the human erythrocyte membrane. Lineweaver-Burk analysis indicates that lanthanum chloride induced inhibition of acetylcholinesterase activity is competitive in nature. The Arrhenius plot shows that the transition temperature of erythrocyte membrane-bound acetylcholinesterase is significantly reduced in the presence of lanthanum chloride. These results suggest that lanthanum chloride increases the fluidity of the erythrocyte membrane and this may be a cause of inhibition of membrane-bound acetylcholinesterase activity.

    • Antiserum directed against cell surface antigens is lethal toLeishmania donovani promastigotes

      Arpita Das Sahana Mazumder Swadesh Duttagupta

      More Details Abstract Fulltext PDF

      The purified flagellar fraction ofLeishmania donovani promastigotes consists of 30–35 polypeptides. Antiserum raised against this fraction reacts with both flagella and pellicular membrane antigens as evident from immunoblot and immunofluorescence studies. Only 3 of these immunoreactive polypeptides are flagellum-specific. The antiserum agglutinates the cells and inhibits their growth in liquid culture medium. Moreover, glucose uptake and glucose-stimulated oxygen uptake of the promastigotes are significantly inhibited by the antiserum. The results indicate that the antiserum has a profound lethal effect on the invitro propagation of the parasite.

    • Induction of glutathione S-transferase in the castor semilooper,Achaea janata (lepidoptera, Noctuidae) following fenitrothion treatment

      V B Yadwad V L Kallapur

      More Details Abstract Fulltext PDF

      Glutathione S-transferase activity was determined in the lepidopteran insect species,Achaea janata, during larval, pupal and adult stages following treatment with sublethal and lethal doses of fenitrothion. Both doses of insecticide produced significant induction of enzyme activity. The rate of induction of enzyme activity was not significantly different in insects that received sublethal and lethal doses of insecticide. Enzyme activity in the different stages of insecticide-treated insects was in the order pupa > adult > larva. However, the inducing effect of the insecticide was higher in larvae, than in pupae and adult. In the absence of induction, the level of enzyme was as much as 3 times higher in midgut tissue than in carcass. In larvae treated with sodium barbitone along with fenitrothion, the knock-down effect of the insecticide was delayed. This was attributed to the increased induction of glutathione S-transferase in the larvae treated with sodium barbitone. The level of reduced glutathione, a rate-limiting factor in the induction of glutathione S-transferase, changed in a cyclic manner in insecticide-treated larvae.

    • Cholesteryl-(2′-hydroxy)-ethyl ether — A potential cholesterol substitute for studies in membranes

      Anil K Lala S Nanda Kumari

      More Details Abstract Fulltext PDF

      The yeast sterol auxotroph GL-7, which grows well on ergosterol and cholesterol, was used to study the ability of cholesteryl-(2′-hydroxy)-ethyl ether to substitute for cholesterol. In this compound the 3j3-hydroxyl group of cholesterol is replaced by ethylene glycol and the resulting ether still retains the amphiphilic character of cholesterol. Cholesteryl-(2Lhydroxy)-ethyl ether was found to support the growth of GL-7 as effectively as cholesterol. Crystal violet permeability and membrane order parameter determined using a spin label were similar for cells grown on these sterols. The ability of such ethylene glycol derivatives to substitute for cholesterol in both artificial and natural membranes should help in designing suitable spacers through which molecules can be linked to cholesterol without affecting the normal function of cholesterol in membranes. This in turn should prove useful in studies with surface-modified liposomes.

    • Purification and properties of trehalase from monkey small intestine

      S Sanker S Sivakami

      More Details Abstract Fulltext PDF

      Brush border membrane trehalase was purified from monkey small intestine by a procedure which includes solubilisation by Triton X-100, ammonium sulphate fractionation, and chromatography on DE-52 and hydroxyapatite. The purified enzyme had a specific activity of 11 units/mg protein and was purified 140-fold. The enzyme showed a single protein band on Polyacrylamide gel electrophoresis. It had aKm value of 17.4 mM for trehalose and a Vmax of 1.33 units. Sucrose and Tris acted as competitive inhibitors of the enzyme.

    • Isolation, purification and partial characterisation of prealbumin from cerebrospinal fluid

      M V Bimanpalli P S Ghaswala

      More Details Abstract Fulltext PDF

      Prealbumin from human cerebrospinal fluid was purified using a combination of ammonium sulphate precipitation, phenol precipitation, Polyacrylamide disc gel electrophoresis and gel filtration on Sephadex G-100. The homogeneity of the purified protein was established by Polyacrylamide gel electrophoresis and Immunoelectrophoresis. On the basis of its molecular weight (55,000), amino acid composition, electrophoretic mobility and immunological cross-reactivity, the prealbumin from cerebrospinal fluid showed complete identity with serum prealbumin. The cerebrospinal fluid prealbumin levels in various neurological disorders may have a diagnostic significance.

    • Structural similarities among the high molecular weight protein fractions of oilseeds

      V Prakash M S Narasinga Rao

      More Details Abstract Fulltext PDF

      Data on the physico-chemical properties of proteins from soybean, groundnut, sesame seed, sunflower seed, safflower seed, mustard seed, rapeseed and cotton seed are fairly extensive. An examination of the available data on high molecular weight proteins suggests that there are similarities in many of their properties. In this report the similarity in amino acid composition, size and shape, molecular weight, secondary structure, subunit composition, association-dissociation at high and low pH, stability towards denaturants, hydrolysis by enzymes and quaternary structure of the high molecular weight proteins is discussed. Based on these similarities a model has been proposed for the associationdissociation, denaturation and reassociation behaviour of the high molecular weight proteins of oilseeds.

    • New analogues of leucine-methionine-enkephalin

      K M Sivanandaiah S Gurusiddappa D Channe Gowda

      More Details Abstract Fulltext PDF

      Nine analogues of the opioid pentapeptides leucine-/ methionine-enkephalinamide, involving replacement of amino acid at position 5 or amino acids at positions 2 and 5, have been synthesized by the solid phase method using mainly 9-fluorenylmethyloxycarbonyl amino acid trichlorophenyl esters in the presence of 1-hydroxybenzotriazole, the solid support being the Merrifield resin. All the analogues were effective in inhibiting the electri cally stimulated contractions of the guinea pig ileum (in vitro) and one of them, tyrosyl-Dnorvalyl-glycyl-phenylalanyl-methioninamide was found to be about 82 times more active than morphine. They also exhibited analgesic activity as well as antidiarrhoeal activity in mice (in vivo).

    • (α-Pyridyl) methyl phosphoro-bis-triazolide as a new phosphorylating reagent for internucleotide bond formation

      K Misra M Chaddha A Dikshit R K Singh

      More Details Abstract Fulltext PDF

      (α-Pyridyl)methyl phosphoro-bis-triazolide has been found to be a reagent of choice for phosphate protection in oligodeoxyribonucleotide synthesis. The reagent has been used successfully to phosphorylate all the four 5’-and N-protected deoxynucleosides. The resulting 3′-phosphorylated derivatives were found to be fairly stable as either triethyl ammonium salts or cyanoethyl derivatives. The phosphorylated derivatives were used in the preparation of the dimers TpT and d(ApT) in solution phase and a tetramer, TTTT, and a hexamer, d(ATATAT), on solid phase using glass support. The method gave excellent yields. Considerably reduced condensation time (6–9 min) and practically no cleavage of the internucleotide bond during the removal of the group are the advantages.

    • Purification and characterisation of prolactin from sheep and buffalo pituitaries

      K Muralidhar Neeraja Chadha Rita Kohli

      More Details Abstract Fulltext PDF

      A study of the problem of structural variants of proteins and their relative contribution to the expressed immunological and biological activity has been initiated using sheep and buffalo prolactins as models. The feasibility of obtaining immunologically and biologically active prolactin in high yields from the discarded ’acid pellet’ of sheep and buffalo pituitaries has been demonstrated. This permits use of the same batch of glands for purifying lutropin, follitropin and prolactin as side fractions. The major component in preparations of buffalo prolactin has a molecular size of 24 kDa. The preparations were active in a radioligand binding inhibition assay and in a rat liver based radioreceptor assay. Charge and size isomers of sheep prolactin and buffalo prolactin have been observed. The reference sheep prolactin did not, in preliminary work, give any indication of being glycosylated. However radioactive sulphate was found to be incorporated into prolactin-rich fractions of sheep and buffalo pituitariesin vitro. By physico-chemical and immunochemical criteria the [35S]-labelled material was similar to standard reference prolactin. The structural implications of sulphation have been probed.

  • Journal of Biosciences | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.