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31.
32.
W Quinkler M Maasberg S Bernotat-Danielowski N Lüthe H S Sharma W Schaper 《European journal of biochemistry》1989,181(1):67-73
Fresh bovine, porcine and canine hearts were homogenized and mitogens for mesoderm-derived cells were purified in three different steps. Extraction by two different ammonium sulfate precipitations was followed by cation-exchange chromatography and by heparin-Sepharose affinity chromatography. A heparin-Sepharose fraction from heart (eluted at 1.1 M NaCl) increased mitotic activity in serum-deprived cultures of porcine aortic endothelial and smooth muscle cells, and in human fibroblasts. This mitogenic activity is potentiated by heparin and inhibited by gamma-interferon. The heart mitogenic fraction showed one double peak on HPLC at A215 and one polypeptide band on SDS/PAGE. These peaks and bands were identical to those obtained from bovine brain. The heart acidic fibroblast growth factor (aFGF) showed a positive signal in Western blots using antibodies raised against brain aFGF. Gas-phase amino acid sequencing established that the mitogens were identical to aFGF and the N-terminally truncated aFGF. Extraction in the presence of a protease inhibitor (pepstatin A) produced a higher-molecular mass form of aFGF with a blocked amino terminus. Another mitogen, eluted at 1.6 M NaCl from heparin-Sepharose, reacted with polyclonal antiserum against human recombinant basic fibroblast growth factor (bFGF) and showed a 66% (12 from 18 amino acids determined by gas-phase sequencing) similarity with bFGF. This polypeptide increased the mitotic activity of the same cell lines but was more potent than aFGF. 相似文献
33.
R I Christopherson K J Schmalzl E Szabados R J Goodridge M C Harsanyi M E Sant E M Algar J E Anderson A Armstrong S C Sharma 《Biochemistry》1989,28(2):463-470
In mammals, dihydroorotase is part of a trifunctional protein, dihydroorotate synthetase, which catalyzes the first three reactions of de novo pyrimidine biosynthesis. Dihydroorotase catalyzes the formation of a peptide-like bond between the terminal ureido nitrogen and the beta-carboxyl group of N-carbamyl-L-aspartate to yield heterocyclic L-dihydroorotate. A variety of evidence suggests that dihydroorotase may have a catalytic mechanism similar to that of a zinc protease [Christopherson, R. I., & Jones, M. E. (1980) J. Biol. Chem. 255, 3358-3370]. Tight-binding inhibitors of the zinc proteases, carboxypeptidase A, thermolysin, and angiotensin-converting enzyme have been synthesized that combine structural features of the substrates with a thiol or carboxyl group in an appropriate position to coordinate a zinc atom bound at the catalytic site. We have synthesized (4R)-2-oxo-6-thioxohexahydropyrimidine-4-carboxylate (L-6-thiodihydroorotate) and have found that this analogue is a potent competitive inhibitor of dihydroorotase with a dissociation constant (Ki) in the presence of excess Zn2+ ion of 0.17 +/- 0.02 microM at pH 7.4. The potency of inhibition by L-6-thiodihydroorotate in the presence of divalent metal ions decreases in the order Zn2+ greater than Ca2+ greater than Co2+ greater than Mn2+ greater than Ni2+; L-6-thiodihydroorotate alone is less inhibitory and has a Ki of 0.85 +/- 0.14 microM. 6-Thioorotate has a Ki of 82 +/- 8 microM which decreases to 3.8 +/- 1.4 microM in the presence of Zn2+. Zn2+ alone is a moderate inhibitor of dihydroorotase and does not enhance the potency of other inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
34.
Aspergillus terreus was isolated from a case of Keratomycosis. The patient, a 50 year old, female presented with a large corneal ulcer with hypopyon. The direct microscopic examination of the scrapings revealed hyaline, thin, septate and branched hyphae. In vitro some antimycotics (amphotericin B,5-fluorocytosine, oxiconazole, amorolfine and ketoconazole) were tested against A. terreus by agar dilution method. Ketoconazole with MIC of 3 gmg/ml after 7 days of incubation was most effective followed by oxiconazole (10g/ml). Experimental corneal ulcer was produced by injecting intralamellary 0.1 ml of the spore suspension containing 10×106 cfu/ml into the eyes of previously immunocompressed albino rabbits. Histopathologic examination showed infiltration and large destruction of the corneal stroma. Subconjunctival oxiconazole therapy exhibited complete cure. Based on our findings, a clinical evaluation of oxiconazole in human keratomycosis seems to be justified. 相似文献
35.
36.
H. K. Goswami Manoj Chandorkar Kakoli Bhattacharya G. Vaidyanath D. Parmar S. Sengupta S. L. Patidar L. K. Sengupta Rajeev Goswami P. N. Sharma 《Human genetics》1990,84(2):172-176
Summary A chromosomal survey using standard lymphocyte cultures employing different media and G-banding techniques was initiated in 1984. This study became particularly important following the tragic gaseous exposure of the population in Bhopal at midnight on 2 December 1984. We have been able to formulate a chromosomal profile for each person whom we have studied; during 1986–1988, 154 persons were examined twice. Among seemingly normal individuals, as many as 20% might possess some chromosomal abnormality; of these, 50% may develop, at a later date, some kind of pathological complication (such as tumours, recurrent abortion or transmission of defects to their offspring). The people exposed to methyl isocyanate have repeatedly shown Robertsonian translocations, mostly in acrocentric chromosomes 13 and 21. Other types of translocations have been studied among all exposed (53) and normal (101) persons; the involvement of chromosomes 5, 9, 11, 14 and 16 is statistically significant (P= <0.001). One of the major clinical symptoms is dyspnoea; we have estimated that almost all seriously dyspnoeic patients have developed at least two categories of chromosomal aberrations, one of which is Robertsonian translocation, in at least 10% metaphases. Our chromosomal survey will be of significance because we are able to identify people with chromosomal aberrations that might be correlated with future pathological consequences of the accident. The chromosomal load that can be sustained with an apparently normal phenotype can also be measured. 相似文献
37.
Supplementation of the growth medium with erosterol, cholesterol and lanosterol enriched the Candida kefyr cells, presumably cell membranes with sterols. Sterol enriched C. kefyr cells showed a decrease in percentage of PHA and Con-A mediated agglutination. Sterol supplementation also increased the sterol: phospholipid ratio and in such cells unsaturated fatty acids predominated over saturated ones. The overall effect of these changes resulted in rigidifying the cell membranes as indicated by shift of break in Arrhenius plots of Mg2+ ATPase. This showed that lectin mediated agglutination of yeast cells may be affected by its membrane fluidity. 相似文献
38.
Pratima Bajpai Anshula Sharma N. Raghuram Pramod K. Bajpai 《Biotechnology letters》1988,10(3):217-220
Summary Ethanol concentration and fermentation productivities were substantially increased when soya extract was added to the fermentation medium using immobilized cells of a locally isolated strain of S. cerevisiae. Very high concentrations, 152 and 162 g/l of ethanol, were obtained from a medium containing 300 and 350 g/l sugars respectively by supplementing the medium with soya extract. The fermentation time was also reduced by more than 50%. 相似文献
39.
It has been well documented that vascular smooth muscle (VSM) reactivity, as well as calcium sensitivity in response to neurotransmitters is increased in a number of blood vessels in established hypertension. Regulation of VSM reactivity involves the interaction of neurotransmitters and blood-borne hormones with specific receptors on target cell membranes. This results in phospholipase-C-mediated hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) and the generation of two second messengers: inositol 1,4,5 trisphosphate (IP3) and diacylglycerol (DAG) both of which act synergistically to produce muscle contraction. We will summarize recent findings in this review which suggest that in essentially hypertensive patients and spontaneously hypertensive rats (SHR), the activation of phospholipase C in response to hormones is increased. Further, we will discuss how increases in phospholipase C activation via GTP-binding proteins may explain the observed increases in Ca2+ influx through potential- and receptor-operated Ca2+ channels, increased activation of protein kinase-C and increased [Ca2+]i in hormone-stimulated blood platelets and VSM cells in the hypertensive state. In addition to these defects, a decrease in the plasma membrane Ca2+ pump and Ca2+-binding proteins has been demonstrated in hypertension. Thus, it appears that the defect in Ca2+ metabolism in the hypertensive vessels is multifocal. All these defects in Ca2+ metabolism together may lead to an increase in peripheral vascular resistance with a concomitant increase in blood pressure. 相似文献
40.
Lanthanum belongs to the group of elements known as “lanthanons,” which also includes cerium, europium, promethium, and thulium. It is the most electropositive element of the rare earth group, is uniformly trivalent, and is similar in its chemical properties to the alkaline earth elements. The effects of this element and its compounds on cellular systems are of considerable interest because of their increasing use in industry and as a substitute or antagonist for calcium in a variety of cellular reactions. Lanthanum is also being employed extensively in studying anatomical barriers, membrane structure, and subcellular transport systems, particularly the calcium pathway. 相似文献