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971.
Oscar Lazcano Jorge Bilbao Robert S. Beissner Martha Vandiver Chin Yang Li 《Biotechnic & histochemistry》1992,67(1):14-20
Permanent preparations of air dried synovial fluids were prepared by staining calcium compounds with alizarin red S stain; each slide was coverslipped with Permount. Variables studied were: (a) concentration of the solution of alizarin red S, (b) pH of staining solution, (c) time of incubation in staining solution and aqueous and ethanolic content of staining solution. The staining effect of each solution was tested on calcium pyrophosphate dihydrate, calcium oxalate, apatite and monosodium urate (MSU). Of all the solutions, best results were obtained with 0.25% alizarin red S in 50% ethanol at pH 7.0 for 30 min. With this solution, the calcium-containing compounds were well stained. MSU did not stain and still preserved negative birefringence on polarizaton. Fixation of smears with ethanol served a double purpose: It fixed the slides without dissolving or removing MSU or the calcium compounds, yet it did dissolve five corticosteroids commonly used for intra-articular injection which may interfere with interpretation of compensated polarized light microscopy of synovial fluids. 相似文献
972.
本文报道石刁柏胚性愈伤组织的可溶性蛋白质含量与组分、过氧化物酶和酯酶的活力及同工酶带均比其体细胞胚的要少。而在体细胞胚胎发生过程中,过氧化物酶和酯酶活力、可溶性蛋白质含量均以球形胚为最低,子叶分化期胚为最高而呈递增趋势;可溶性蛋白质组分以子叶分化期胚、成熟胚为最多,球形胚、香蕉形胚为最少;过氧化物酶同工酶带以梨形胚为最多,子叶分化期胚、成熟胚为最少;酯酶同工酶则以子叶分化期胚为最多,成熟胚为最少。胚性愈伤组织与体细胞胚均有其特异性可溶性蛋白质及同工酶带,可作为体细胞胚胎发生的分子标记。 相似文献
973.
中国大麦叶绿体DNA和核糖体RNA基因限制性片段长度多型性 总被引:6,自引:1,他引:5
本文报道了我们对我国不同大麦区80份大麦品种叶绿体DNA和核糖体RNA基因限制性片段长度多型性的研究。结果表明:rDNA间隔序列长度存在丰富的多样性,80份材料中出现了8种长度变异炎型共组成8种表现型。长度变异类型及其表现型在地理分布上存在着明显的区域性。推测这种分布上的地区性与植物对环境的适应性有关。所用的两个叶绿体DNA克隆片段未检测到限制性片段长度多型性,说明栽培大麦叶绿体DNA变异程度低。 相似文献
974.
J Iwamoto M Yoshinaga S P Yang E Krasney J Krasney 《Journal of applied physiology》1992,73(6):2226-2232
Cerebral vasodilation in hypoxia may involve endothelium-derived relaxing factor-nitric oxide. Methylene blue (MB), an in vitro inhibitor of soluble guanylate cyclase, was injected intravenously into six adult ewes instrumented chronically with left ventricular, aortic, and sagittal sinus catheters. In normoxia, MB (0.5 mg/kg) did not alter cerebral blood flow (CBF, measured with 15-microns radiolabeled microspheres), cerebral O2 uptake, mean arterial pressure (MAP), heart rate, cerebral lactate release, or cerebral O2 extraction fraction (OEF). After 1 h of normobaric poikilocapnic hypoxia (arterial PO2 40 Torr, arterial O2 saturation 50%), CBF increased from 51 +/- 5.8 to 142 +/- 18.8 ml.min-1 x 100 g-1, cerebral O2 uptake from 3.5 +/- 0.25 to 4.7 +/- 0.41 ml.min-1 x 100 g-1, cerebral lactate release from 2 +/- 10 to 100 +/- 50 mumol.min- x 100 g-1, and heart rate from 107 +/- 5 to 155 +/- 9 beats/min (P < 0.01). MAP and OEF were unchanged from 91 +/- 3 mmHg and 48 +/- 4%, respectively. In hypoxia, 30 min after MB (0.5 mg/kg), CBF declined to 79.3 +/- 11.7 ml.min-1 x 100 g-1 (P < 0.01), brain O2 uptake (4.3 +/- 0.9 ml.min-1 x 100 g-1) and heart rate (133 +/- 9 beats/min) remained elevated, cerebral lactate release became negative (-155 +/- 60 mumol.min-1 x 100 g-1, P < 0.01), OEF increased to 57 +/- 3% (P < 0.01), and MAP (93 +/- 5 mmHg) was unchanged. The sheep became behaviorally depressed, probably because of global cerebral ischemia. These results may be related to interference with a guanylate cyclase-dependent mechanism.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
975.
976.
The MAS-encoded processing protease of yeast mitochondria. Overproduction and characterization of its two nonidentical subunits 总被引:5,自引:0,他引:5
V Geli M J Yang K Suda A Lustig G Schatz 《The Journal of biological chemistry》1990,265(31):19216-19222
The amino-terminal presequences of proteins imported from the cytoplasm across the mitochondrial inner membrane are cleaved off by a soluble matrix-localized protease composed of two nonidentical homologous subunits. In the yeast Saccharomyces cerevisiae, these are encoded by the nuclear MAS1 and MAS2 genes. We have now constructed yeast strains in which either one or both of the genomic MAS genes are controlled by a galactose-inducible strong promoter. In these strains, the intramitochondrial concentration of each MAS-encoded subunit as well as of the holo-protease can be varied over a wide range. When overproduced, the MAS1 protein precipitates in the matrix whereas the MAS2 protein remains soluble. The MAS2 protein was obtained at a purity of 98% in milligram amounts. The purified MAS2 subunit exists largely as a soluble 52-kDa monomer. Its cleavage activity is very low and might well reflect the 2% contamination by holoprotease. Activity is restored by adding the solubilized purified MAS1 subunit. Yeast cells depleted of one or both MAS subunits continue to import precursor proteins into mitochondria, but fail to cleave them; eventually the deficient cells stop growing. This growth arrest is partly suppressed on minimal medium or under conditions in which the cells are less dependent on mitochondrial metabolism. Depletion of the MAS1 subunit causes overproduction of the MAS2 subunit. 相似文献
977.
N B Nazhat G Yang R E Allen D R Blake P Jones 《Biochemical and biophysical research communications》1990,166(2):807-812
Pulse radiolysis studies show that the spin trap 3,5,dibromo-4-nitrosobenzene sulphonate (I) reacts rapidly with O2.- but the product formed is very unstable. No radicals were detected in ESR studies of solutions of I after reaction with O2.- formed by gamma-radiolysis. Evidence is presented that the stable radical observed by some, but not all workers, following exposure of I to the O2.(-)-generating xanthine/xanthine oxidase system, is produced by a peroxidatic oxidation using hydrogen peroxide formed by O2-. dismutation and that formation of this radical depends on the presence of peroxidase activity in the xanthine oxidase sample employed. 相似文献
978.
Two forms of type-1 protein phosphatase activating factor (FA) termed FA1 and FA2 have been identified in plasma membranes of pig brain. FA1 is spontaneously active and trypsin-labile whereas FA2 is inactive and trypsin-resistant. Phospholipid reconstitution studies further indicate that the FA activity in the neutral phospholipids-reconstituted complex is spontaneously active and trypsin-labile whereas the FA activity in the acidic phospholipids-reconstituted complex is trypsin-resistant and inactive. The results indicate that inactive FA2 may have its catalytic domain interacted with negatively-charged phospholipids in brain membranes. This provides initial evidence for the regulation of protein kinase FA (a transmembrane signal of insulin and epidermal growth factor) in the central nervous system. 相似文献
979.
S D Yang L S Kao H C Chen Y H Chou D S Chen 《Biochemical and biophysical research communications》1990,169(3):921-926
The ATP.Mg-dependent protein phosphatase activating factor (protein kinase FA) has been identified to exist in neuroblastoma x glioma hybrid 108-15 cells (NG108-15 cells). More importantly, when NG cells were induced to differentiate with N6, O2'-dibutyryl adenosine 3',5'-cyclic monophosphate (dibutyryl cAMP), the cellular activity of kinase FA was found to increase dramatically. Time course study further revealed that induction of differentiation in NG cells by dibutyryl cAMP treatment increased the FA activity to over 3 times the levels found in undifferentiated cells and in a linear day-dependent manner, indicating that the FA activity level is correlated with the state of differentiation of NG108-15 cells. This is the first report providing initial evidence that protein kinase FA (a transmembrane signal of insulin) is involved in the induction of neuronal cell differentiation. 相似文献
980.
Notexin from Notechis scutatus scutatus snake venom was modified with trinitrobenzenesulfonic acid, and the major trinitrophenylated (TNP) derivative was separated by high-performance liquid chromatography. Modification resulted in the incorporation of only one TNP group on the N-terminal alpha-amino group. The TNP derivative showed a precipitous decrease in enzymatic activity and lethal toxicity, whereas the antigenicity remained unchanged. However, trinitrophenylation did not significantly affect the secondary structure of the toxin molecule as revealed by the CD spectra. The results, that the modification reaction was accelerated by the Ca2+ and that the TNP derivative retains its affinity for Ca2+, indicate that the N-terminal alpha-amino group did not participate in the Ca2(+)-binding. The TNP derivative could be regenerated with hydrazine hydrochloride. The biological activities of the regenerated notexin are almost the same as those of native notexin. These results suggest that the N-terminal alpha-amino group is essential for the phospholipase A2 activity and lethal toxicity of notexin, and that incorporation of the TNP group on the N-terminal alpha-amino group might give rise to a distortion of the active conformation of notexin. 相似文献