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81.
Monoclonal antibodies to adult chicken myosin light chains were generated and used to quantitate the types of myosin light-chain (MLC) isoforms expressed during development of the pectoralis major (PM), anterior latissimus dorsi (ALD), and medial adductor (MA) muscles of the chicken. These are muscles which, in the adult, are composed predominantly of fast, slow, and a mixture of fiber types, respectively. Three distinct phases of MLC expression characterized the development of the PM and MA muscles. The first identifiable pase occurred during the period of 5-7 d of incubation in ovo. Extracts of muscles from the pectoral region (which included the presumptive PM muscle) contained only fast MLC isoforms. This period of exclusive fast light-chain synthesis was followed by a phase (8- 12 d of incubation in ovo) in which coexpression of both fast and slow MLC isoforms was apparent in both PM and MA muscles. During the period, the composition of both fast and slow MLC isoforms in the PM and MA muscles was identical. Beginning at day 12 in ovo, the ALD was also subjected to immunochemical analyses. The proportion of fast and slow MLCs in this muscle at day 12 was similar to that present in the other muscles studied. The third development phase of MLC expression began at approximately 12 d of incubation in ovo and encompassed the transition in MLC composition to the isoform patterns incubation in ovo and encompassed the transition in MLC composition to the isoform patterns typical of adult muscle. During this period, the relative proportion of slow MLC rose in both the MA and ALD and fell in the PM. By day 16, the third fast light chain, LC(3f), was apparent in extracts of both the PM and MA. These results show that there is a developmental progression in the expression of MLC in the two avian muscles studied from day 5 in ovo; first, only fast MLCs are accumulated, then both fast and slow MLC isoforms are expressed. Only during the latter third of development in ovo is the final MLC isoform pattern characteristic of a particular muscle type expressed. 相似文献
82.
M.C. Srinivasan R.Rama Rao S.S. Deshmukh N.A. Sahasrabudhe 《Enzyme and microbial technology》1983,5(4):269-272
Production of microbial biomass through fermentation of pretreated rice straw using Penicillium janthinellum (St-F-3B) is reported, with emphasis on the use of non-effluent generating pretreatment procedures. The fungus readily metabolized a rice straw substrate that had been subjected to alkali pretreatment by steaming at atmospheric pressure followed by the neutralization of the alkali. The crude protein content of the microbial biomass averaged 15–20%. The fermentation could be carried out in aerated-agitated fermenters using fertilizer grade nutrient salts to produce a biomass with 17.5% crude protein. When operated on a semicontinuous basis using 20% of the previous batch as inoculum, successive batches produced a biomass product with 12–19% crude protein content in 48 h. The problems of developing a technology for protein from agricultural residues with particular reference to developing countries are discussed. 相似文献
83.
Decreased Benzodiazepine Receptor Density in Rat Cerebellum Following Neurotoxic Doses of Phenytoin 总被引:2,自引:1,他引:1
Abstract: The effect of acute and chronic administration of phenytoin on [3H]-flunitrazepam binding was examined in the rat cerebellum. There was no significant effect of phenytoin on [3H]flunitrazepam binding in the rat cerebellum 1 and 6 h after a single i.p. injection of 200 mg/kg of phenytoin. However, after 14 days and 28 days of chronic phenytoin administration, significant de-creases in [3H]flunitrazepam receptor density were observed, with no changes in apparent affinity constants in the rat cerebellum. This effect of phenytoin was dose-dependent, as lower doses of phenytoin (100 mg/kg/day) for 14 or 28 days produced no alterations in [3H]flunitrazepam binding in the rat cerebellum. Light-microscopic examination of the rat cerebellum treated with 200 mg/kg/day of phenytoin for 14 days showed degeneration of the Purkinje cells, with edematous Bergmann astrocytes. These data provide evidence for the neuronal localization of benzodiazepine receptors on cerebellar Purkinje cells. 相似文献
84.
85.
Modulation of renal epithelial cell growth by glucosylceramide. Association with protein kinase C, sphingosine, and diacylglycerol. 总被引:9,自引:0,他引:9
J A Shayman G D Deshmukh S Mahdiyoun T P Thomas D Wu F S Barcelon N S Radin 《The Journal of biological chemistry》1991,266(34):22968-22974
Two independent approaches were employed to explore the potential role of endogenous glucosylceramide or a closely related glucosphingolipid in mediating the cellular proliferation of Madin-Darby canine kidney cells. First, cultured cells were depleted of glucosphingolipids by exposure to a glucosylceramide synthase inhibitor, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol. This agent markedly inhibited cell growth and DNA synthesis in a time- and concentration-dependent manner. Second, cells were grown in the presence of conduritol B epoxide, an inhibitor of glucosylceramide beta-D-glucosidase. Exposure of cells to this inhibitor resulted in the time-dependent accumulation of glucosylceramide with a corresponding increase in cellular proliferation. Alterations in protein kinase C activity were evaluated as a potential mechanism for these effects on growth. Both membrane- and cytosol-associated protein kinase C (PKC) activity declined under conditions of glucosylceramide synthase inhibition and increased under conditions of beta-glucosidase inhibition. The changes in PKC activity were evident after DEAE-cellulose purification. Diacylglycerol levels increased in response to both glucosylceramide synthase and beta-glucosidase inhibition. Ceramide and sphingosine levels changed only in the presence of D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol, increasing due to lack of conversion to glucosylceramide. However, the elevation in endogenous sphingosine was probably insufficient to account for the decrease in PKC, considering the high level of diacylglycerol in the cells. These data demonstrate an association between glucosylceramide levels, PKC activity, and cell growth. 相似文献
86.
It was necessary to make sections of small unfixed specimens which had been frozen while still immersed in their normal culture medium. The principal difficulty stemmed from the poor sectioning quality of the frozen culture medium. A capsule is described which has a narrow well in which the tissue specimen fits snugly within a small amount of culture medium. After freezing, the whole capsule is sectioned and the resulting sections, being nearly devoid of culture medium, are of good quality. 相似文献
87.
Summary
Penicillium
funiculosum and its mutants namely BU-36 and N-4 responded differently to the addition of fatty acids. Addition of 0.1% oleic, linoleic, and linolenic acids resulted in significant increase in extracellular exo-glucanase and -glucosidase in wild and N-4 strains, whereas no appreciable increase was noticed in BU-36. However, BU-36 showed positive response with 0.1% palmitic and stearic acids. In all the strains, the addition of different fatty acids did not have any effect on endoglucanase activity. Our results indicate that fatty acids do have a role in the release of the cell-bound cellulolytic enzymes.NCL Communication No. : 4113 相似文献
88.
C V Gudipati M H Weil R J Gazmuri H G Deshmukh J Bisera E C Rackow 《Journal of applied physiology》1990,68(4):1405-1408
We investigated the aortic, mixed venous, and great cardiac vein acid-base changes in eight domestic pigs during cardiac arrest produced by ventricular fibrillation and during cardiopulmonary resuscitation (CPR). The great cardiac vein PCO2 increased from a control value of 52 +/- 2 to 132 +/- 28 (SD) Torr during CPR, whereas the arterial PCO2 was unchanged (39 +/- 4 vs. 38 +/- 4). The coronary venoarterial PCO2 gradient, therefore, increased remarkably from 13 +/- 2 to 94 +/- 29 Torr. The simultaneously measured great cardiac vein lactate concentrations increased from 0.24 +/- 0.06 to 7.3 +/- 2.34 mmol/l. Much more moderate increases in the lactate content of aortic blood from 0.64 +/- 0.25 to 2.56 +/- 0.27 mmol/l were observed. Increases in great cardiac vein PCO2 and lactate were highly correlated during CPR (r = 0.91). After successful CPR, the coronary venoarterial PCO2 gradient returned to normal levels within 2 min after restoration of spontaneous circulation. Lactate content was rapidly reduced and lactate extraction was reestablished within 30 min after CPR. These studies demonstrate marked but reversible acidosis predominantly as the result of myocardial CO2 production during CPR. 相似文献
89.
K L Meert D R Deshmukh B Marescau P P De Deyn A P Sarnaik 《Biochemical medicine and metabolic biology》1991,46(2):208-214
Guanidino compounds are synthesized from arginine in various tissues such as liver, kidney, brain, and skeletal muscle. Guanidino compounds such as arginine and creatine play an important role in nitrogen metabolism, whereas other guanidino compounds such as guanidinosuccinic acid and alpha-N-acetylarginine are known toxins. In order to understand the changes in the metabolism of guanidino compounds during ammonia toxicity, we investigated the effect of hyperammonemia induced by an ammonium acetate injection on the levels of guanidino compounds in plasma, liver, kidney, and brain of rats. Control animals were injected with an equal volume of saline. Blood and tissues were removed 1 h following ammonium acetate or saline injection and guanidino compounds were analyzed by high-performance liquid chromatography. Plasma and kidney levels of guanidinosuccinic acid were significantly elevated in rats challenged with ammonium acetate. Brain alpha-N-acetylarginine levels were also significantly higher in rats injected with ammonium acetate as compared to those in controls. Our results suggest that guanidinosuccinic acid and alpha-N-acetylarginine may play an important role in hyperammonemia. 相似文献
90.
alpha-Aminoadipate aminotransferase and kynurenine aminotransferase activities from rat kidney are reportedly associated with the same protein. We observed that when the supernatant fraction was maintained at pH 4.5 for 75 min, 100% of kynurenine aminotransferase activity was lost, whereas only 40% of aminoadipate aminotransferase activity was lost. We purified alpha-aminoadipate aminotransferase and kynurenine aminotransferase from rat kidney supernatant fraction to electrophoretic homogeneity by ammonium sulfate fractionation, DEAE-Sephacel, and hydroxylapatite chromatography. Kynurenine aminotransferase activity was precipitated by pH treatment. The remaining aminoadipate aminotransferase activity was concentrated and injected into rabbits to raise antibodies that were used to prepare an affinity column. A mixture of aminoadipate aminotransferase and kynurenine aminotransferase activities obtained after hydroxylapatite chromatography was subjected to affinity chromatography. Aminoadipate aminotransferase and kynurenine aminotransferase activities resolved as separate peaks, providing evidence that the two activities are associated with two different proteins. 相似文献