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71.
72.
T. P. Afanasieva S. Yu. Filippovich V. Yu. Sokolovsky M. S. Kritsky 《Archives of microbiology》1982,133(4):307-311
The specific activity of NAD+ kinase (ATP:NAD+ 2-phosphotransferase, EC 2.7.1.23) from Neurospora crassa shows sharp peaks when the organism enters a new developmental stage of the asexual life cycle: the peaks are observed during hydration and germination of conidia, at the transition from exponential to stationary growth and at the photostimulated conidiation. As stimulation of NAD+ kinase activity by light in conidiating mycelium is not sensitive to translation inhibitors, the activiation of pre-existing molecules, rather than induction of protein synthesis de novo may be supposed. Enzyme electrophoresis revealed the presence of four forms of NAD+ kinase having different apparent molecular weights (I=333,000; II=306,000; III=229,000 and IV=203,000). Manifestation of the activity of individual forms of NAD+ kinase is developmentally controlled: form III is most abundant during vegetative growth, forms I and II prevail in conidia. At the conidial germination the increase of NAD+ kinase activity is associated with the activation of form III, whereas during photostimulation of conidiation form II is the most activated one. Therefore, certain molecular forms of the enzyme may be regarded as biochemical markers for different developmental stages of N. crassa. 相似文献
73.
The Immunological Identification of Brain Proteins on Cellulose Nitrate in Human Demyelinating Disease 总被引:11,自引:9,他引:2
Abstract: An immunological technique has been employed to identify proteins, separated in polyacrylamide gels, which show changes in brain samples from cases of multiple sclerosis and subacute sclerosing panencephalitis. Sodium dodecylsulphate-treated proteins in particulate and soluble fractions were separated in polyacrylamide slab gels, transferred electrophoretically onto cellulose nitrate sheets, incubated with specific antisera and visualized by an immunoperoxidase method. Protein bands showing changes were identified using antisera raised against the myelin basic and Wolfgram proteins, the neurofilament triplet proteins, tubulin and glial fibrillary acidic protein. In addition to the loss of myelin proteins, decreases in the neurofilament proteins and in tubulin were seen in both multiple sclerosis and subacute sclerosing panencephalitis samples. The distribution of glial fibrillary acidic protein polypeptides in the particulate and soluble fractions of plaque samples appeared to vary according to the degree of fibrosis. Changes in the levels of the myelin-associated glycoprotein, the lower molecular weight component of the Wolfgram protein, albumin and immunoglobulin G, none of which were visualized by protein staining, were also seen. This immunological technique has allowed a closer examination of changes occurring in brain protein spectra in multiple sclerosis and subacute sclerosing panencephalitis. 相似文献
74.
Certain neuroleptic drugs, such as spiperone and (+) butaclamol, can discriminate between two populations of [3H]5-hydroxytryptamine ([3H]5-HT) binding sites in rat brain. The butyrophenone neuroleptic spiperone shows the greatest selectivity for these two binding sites, having at least a 3000-fold difference between its dissociation constants (2-12 nM versus 35,000 nM) for the high- and low-affinity sites, respectively. Inhibition of [3H]5-HT binding by spiperone in rat frontal cortex and corpus striatum yields distinctly biphasic inhibition curves with Hill slopes significantly less than unity. Results from nonlinear regression analysis of these inhibition studies were consistent with a two-site model in each brain region. In the frontal cortex the high-affinity neuroleptic sites comprised about 60% of the total [3/H]5-HT binding sites whereas in the corpus striatum they accounted for only 20% of the sites. Furthermore, saturation studies of [3H]5-HT binding assayed in the absence or presence of 1 μM-spiperone (a concentration that completely blocks the high-affinity site while having minimal activity at the low-affinity site) reveal a parallel shift in the Scatchard plot with no change in the dissociation constant of [3H]5-HT, but a significant decrease (64% in frontal cortex or 28% in corpus striatum) in the number of specific binding sites. These observations are consistent with the existence of at least two populations of [3H]5-HT binding sites having a differential regional distribution in rat brain. 相似文献
75.
Summary The influence of continuous cropping and soil test based fertilizer use on the organic nitrogen fractions in the plough layer
has been studied in a Typic Ustochrept soil. Seven years of multiple cropping without manuring caused marked depletion in
all the hydrolysable fractions except unidentified hydrolysable N namely, hexosamine (48.8%), hydrolysable ammonium (23.9%)
and amino acid (7.3%) as compared to an adjacent fallow. Fertilizer nitrogen application maintained the levels of various
forms of N as in the fallow plots and nitrogen in conjunction with phosphorus raised the status of amino acid N. Phosphate
improved the contents of hydrolyzable ammonium and total hydrolyzable N whereas farmyard manure enhanced the latter only.
The system of intensive cropping followed with appreciably high doses of fertilizers favoured greater immobilization of N
in hydrolyzable ammonium and total hydrolyzable fractions.
Original not seen 相似文献
76.
Effects of Detergents, Proteins, and Lipids on 2'':3''-Cyclic-Nucleotide 3''-Phosphodiesterase Activity 总被引:3,自引:3,他引:0
The myelin marker 2':3'-cyclic-nucleotide 34'-phosphodiesterase (CNPase) was isolated to a lipid- and phosphate-free stage. The effects of exogenously added lipids were tested on this preparation and compared to the known stimulation of the enzyme by detergents and proteins. CNPase could be stimulated 2-3 fold by these various agents which appeared to be additive in their effect. Enzyme-protein and enzyme-lipid interactions and possible medical use of the improved assay conditions for CNPase employed in the study are discussed. 相似文献
77.
Dr. V. Arunachalam Dr. A. Bandyopadhyay 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1979,54(5):203-207
Summary A set of complex crosses with multiple crosses as female parents were made using multiple pollen in turnip rape (Brassica campestris L.). These multiple cross — multiple pollen hybrids (mucromphs) were evaluated for a large number of quantitative characters including yield. New methods were proposed to study such genetic material in depth so as to formulate suitable strategies to breed for attractive seed yield.Part of the Ph. D. Thesis of junior author submitted to Indian Agricultural Research Institute, New Delhi 相似文献
78.
Summary When horseshoe crab embryos were treated with NaHCO3 at the developmental stage when the germ disc appears, multiple embryos were formed. NaHCO3 may effect the formation of multiple embryos by binding Ca2+ ions of the embryo since multiple embryos were also formed by treatment with Ca2+ free sea water.The treatment caused the blastoderm layer to tear. When the embryos were returned to normal sea water after the treatment, the blastoderm recovered. Some cell masses, probably derived from the germ disc or its prospective cells, formed during the process of the recovery. Each cell mass developed into an embryo.Contributions from the Shimoda Marine Research Center, Nor. 348 相似文献
79.
Posterior probabilities for choosing a regression model 总被引:4,自引:0,他引:4
80.
M. E. Ghitany 《Biometrical journal. Biometrische Zeitschrift》1993,35(1):15-27
The aim of this paper is to study the properties of the asymptotic variances of the maximum likelihood estimators of the parameters of the exponential mixture model with long-term survivors for randomly censored data. In addition, we study the asymptotic relative efficiency of these estimators versus those which would be obtained with complete follow-up. It is shown that fixed censoring at time T produces higher precision as well as higher asymptotic relative efficiency than those obtainable under uniform and uniform-exponential censoring distributions over (0, T). The results are useful in planning the size and duration of survival experiments with long-term survivors under random censoring schemes. 相似文献