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2.
H. O. Jauregui P. N. McMillan J. Driscoll S. Naik 《In vitro cellular & developmental biology. Plant》1986,22(1):13-22
Summary Long-term monolayer cultures of adult rat hepatocytes were tested for their ability to glucuronize phenol red and to maintain
initial levels of cell proteins, glucose consumption, and lactic acid production. Lactate dehydrogenase leakage served as
an index of culture status because a high value indicates cell death. Three tissue culture (TC) media formulations were the
main variables introduced to determine ideal conditions for cell survival in vitro. Investigations of long-term cultures were
preceded by studies of hepatocyte attachment to polystyrene surfaces. This attachment was influenced by the amount of substrate
deposited and the number of cells seeded, but not by the uniformity of the substrate coating. A statistical analysis of our
data revealed that in the absence of fetal bovine serum (FBS), air dried collagen (ADC) and Biomatrix (BMX) were superior
to saline precipitated collagen and fibronectin as attachment substrates. In the presence of 10% FBS, all of the substrates
performed equally.
Chee's Medium (CEM) proved to be the best for preserving cell proteins over a time course of 28 d and Williams' E medium also
performed adequately up to 14 d. The glucuronization of phenol red was at 50% of initial values at Day 7 in CEM-ADC hepatocytes
in contrast to 30% for cells in Williams' E medium and 5% for cells grown in Waymouth's. At 14 d glucuronization was still
present at 40% of original values in CEM-ADC cells but had ceased in the other two media. When BMX was used, none of the TC
media supported glucuronization levels comparable to ADC cells.
This research was supported in part by grant 1R01-AM-26520 from the National Institute of Arthritis, Diabetes and Digestive
Kidney Diseases, NIH, Bethesda, Maryland. 相似文献
3.
S Naik J E Oates A Dell G W Taylor P M Dey J B Pridham 《Biochemical and biophysical research communications》1985,132(1):1-7
A fast atom bombardment mass spectrometric protocol has been developed to determine the type of oligosaccharide chain present in glycoproteins. The procedure is based on acetolysis of the intact glycoconjugate, extraction of the peracetylated carbohydrate fragments and analysis by fast atom bombardment mass spectrometry. The molecular ions present in the FAB spectra uniquely define the composition of the oligosaccharides with respect to hexose, aminohexose and sialic acid content. High mannose oligosaccharides yield a series of peracetylated hexose oligomers whereas complex-type oligosaccharides afford a series of N-acetyl-lactosamine containing species. Fucosylation is usually not detected but sialylated oligosaccharides are readily identified and the type of sialic acid is also defined. The method has been tested on three glycoproteins of known structure - fetuin, ribonuclease B and erythrocyte Band 3 - and on a glycoprotein of unknown structure - alpha-galactosidase I, an enzyme lectin from Vicia faba. The latter is shown to contain high mannose carbohydrate chains. 相似文献
4.
M. S. Naik D. J. D. Nicholas 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,72(6):735-736
Summary Leaves of young seedlings of a number of tall cultivars of wheat, lacking the dwarfing Rht genes, readily responded to a brief 2 min exposure to CO, as assessed by in vivo aerobic assay of nitrate reductase. This test depends on the inhibition of cytochrome c oxidase by CO, which in turn renders cytosolic NADH available for the reduction of nitrate to nitrite in vivo. Semi-dwarf cultivars of wheat (Rht present) did not respond to CO in this way. Since CO forms a complex only with reduced cytochrome a3, the results indicate differences in the redox state of cytochrome a3, during in situ respiration of leaves from tall and semi-dwarf plants which are likely to be under genetic control. 相似文献
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6.
The activity of cotyledon and embryo diamine oxidase was reduced by feeding ethrel and chloroethanol to the seedlings. The inhibitory effect of 2,4-D on the activity of enzyme in the cotyledon which may be mediated through ethylene was reversed by exposure of seeds to red light. 相似文献
7.
V. K. Sudhakaran B. S. Deshpande J. G. Shewale S. R. Naik 《Biotechnology letters》1992,14(10):913-918
Summary A recirculated packed bed batch reactor has been designed for the production of 6-aminopenicillanic acid. It was observed that the flow rate of penicillin G solution is a rate limiting step for its hydrolysis. Under the conditions used, the maximum rate of hydrolysis of penicillin G was observed at a flow rate of 3.0 L/min. 相似文献
8.
Uromodulin (Tamm-Horsfall glycoprotein/uromucoid) is a phosphatidylinositol-linked membrane protein 总被引:10,自引:0,他引:10
M J Rindler S S Naik N Li T C Hoops M N Peraldi 《The Journal of biological chemistry》1990,265(34):20784-20789
Uromodulin, originally identified as an immunosuppressive glycoprotein in the urine of pregnant women, has been previously shown to be identical to human Tamm-Horsfall glycoprotein (THP). THP is synthesized by the kidney and localizes to the renal thick ascending limb and early distal tubule. It is released into the urine in large quantities and thus represents a potential candidate for a protein secreted in a polarized fashion from the apical plasma membrane of epithelial cells in vivo. After introduction of the full-length cDNA encoding uromodulin/THP into HeLa, Caco-2, and Madin-Darby canine kidney cells by transfection, however, the expressed glycoprotein was almost exclusively cell-associated, as determined by immunoprecipitation after radioactive labeling of the cells. By immunofluorescence, THP was localized to the plasma membranes of transfected cells. In transfected cell extracts, THP also remained primarily in the detergent phase in a Triton X-114 partitioning assay, indicating that it has a hydrophobic character, in contrast to its behavior after isolation from human urine. Triton X-114 detergent-associated THP was redistributed to the aqueous phase after treatment of cell extracts with phosphatidylinositol-specific phospholipase C. Treatment of intact transfected HeLa cells with phosphatidylinositol-specific phospholipase C also resulted in the release of THP into the medium, suggesting that it is a glycosylphosphatidylinositol (GPI)-linked membrane protein. Similar to other known GPI-linked proteins, uromodulin/THP contains a stretch of 16 hydrophobic amino acids at its extreme carboxyl terminus which could function as a GPI addition signal and was shown to label with [3H]ethanolamine. The results indicate that THP is a member of this class of lipid-linked membrane proteins and is released into the urine after the loss of its hydrophobic anchor, probably by the action of a phospholipase or protease. 相似文献
9.
α-Galactosidase from Vicia faba seeds has been resolved into three molecular forms, I, II1 and II2, respectively. Enzyme I is a tetramer (Mr 160 000) consisting of identical sub-units (Mr 44000 ± 2000). All three forms display lectin activity with glucose/mannose specificity. Enzyme I has been further studied with respect to its lectin specificity and various factors affecting this property. The results indicate that the catalytic and the lectin sites reside in the same protein molecule. The results presented are unique in that the enzyme activity is specific for galactose and its lectin activity is specific for glucose/mannose. 相似文献
10.
Summary The effect of methallibure (ICI 33,828) on the pituitary-gonad and the pituitary-thyroid axes of the Indian garden lizard, Calotes versicolor was studied. Following administration of methallibure B2 (FSH) and B3 (ICSH) cells of the pars distalis exhibited significant alterations with concomitant changes in the seminiferous tubules, and in the interstitial cells and epididymis respectively. B1 (TSH) cells exhibited conspicuous hypertrophy and degranulation which was reflected in dramatic changes in thyroid morphology. The caudally localized acidophilic A1 (PRL) cells also showed hypertrophy, hyperplasia and intense granulation. The rostrally located A2 (STH) acidophils and the B4 (ACTH) cells were unaffected by the treatment. The possible mode of action of this drug is discussed in the light of available literature.Supported by a grant from the University Grants Commission of India. The generous supply of methallibure by Dr. A.L. Walpole of the Imperial Chemical Industries Limited, England, through Professor C.J. Dominic, Banaras Hindu University, is gratefully acknowledged 相似文献