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71.
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Thermal stability of the ferricyanide (FC) and dichlorophenolindophenol (DCIP) reducing reactions was investigated in isolated membrane preparations and PS II particles with active water splitting system from the cyanobacterium Synechococcus elongatus. In a hypotonic medium, the thermostability was seen to be much higher for the DCIP than for the FC reduction reaction. After the addition of high concentrations of polyethylene glycol (Mwt = 4000) or sodium citrate to the medium, the FC reduction reaction appeared to be more temperature resistant. Data on the effects of temperature, DCMU and detergents on the electron transfer rate in PS II provide evidence suggesting that the different thermal stabilities of the two reactions are due to different physico-chemical properties of the electron donor sites to FC and DCIP. The data suggest that regions of contact between individual macromolecular complexes of the electron transport chain are the most labile sites of the photosynthetic apparatus. The role of the composition and properties of the intracellular medium on thermostability are emphasized. 相似文献
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The influence of Ag+ (0.5-10 microM) on Escherichia coli K-12 cells was studied by electrophoresis and electro-orientation spectroscopy methods. It was shown that the pH-dependency of the cell electrokinetic potential (phosphate-citrate buffer with ion strength 0.02) practically didn't changed after Ag+ treatment, but in low-conductive media electrophoretical mobility of intact and inactivated by heat (70 degrees, 15 min) cells gradually decreased as the Ag+ concentration increased. It was due to the Ag+ adsorption on the cell surface and could not be used for the definite characterization of the cell damage. The high-frequency decrease in the cell electro-orientation spectrum shifted to the region of lower frequencies, K+ was excreted by cells, slight raise of the medium pH occurred and significant changes of cell osmotic properties were observed as a result of Ag+ action. All these changes showed the disturbance of barrier properties of the cytoplasmic membrane. Besides the damaging action of Ag+ on cell membranes increased with the decrease of pH and decreased after the addition of Mg2+, Ca2+ and Sr2+ in low concentrations. 相似文献
76.
Both single and graded administration of an anthracycline antibiotic adriablastine at a dose of 20 mg/kg to white rats have resulted in cardiomyocyte volume decrease, dystrophia and lysis of myofibrils, and reduction of mitochondrial surface density volume. Accumulations of myelin bodies of different configuration and diffuse myolysis were observed. Myelin bodies and diffuse myolysis of cardiomyocytes in adriablastine-induced cardiomyopathy are believed to be a morphological sign of lipid peroxidation. 相似文献
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N. P. Teryukova O. N. Pogodina G. I. Blinova V. A. Ivanov 《Cell and Tissue Biology》2011,5(6):586-594
The goal of this work consisted in study of the immunomodulating action of the cytostatic drug cyclophosphamide (CP) on the
natural cytotoxic activity of rat and mice splenocytes. The cytotoxicity of effector cells (EC) with respect to monolayer
cell lines of the Zajdela rat hepatoma and the HTC rat hepatoma and of the MH-22a mouse hepatoma was determined with the aid
of morphometric analysis. CP at a dose of 100 mg/kg 48 h after administration to animals has been shown to produce an immunomodulating
effect on cytotoxicity of splenocytes—a suppressive one with respect to cell-targets (CT) of Zajdela hepatoma and an immunopotentiating
one with respect to CT of HTC and MH-22 hepatomas. Possible mechanisms of the CP immunopotentiating action are discussed. 相似文献
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Vasilyeva A. D. Ivanov V. S. Yurina L. V. Indeykina M. I. Bugrova A. E. Kononikhin A. S. Nikolaev E. N. Rosenfeld M. A. 《Doklady. Biochemistry and biophysics》2021,501(1):419-423
Doklady Biochemistry and Biophysics - Plasminogen is a zymogenic form of plasmin, an enzyme that plays a fundamental role in the dissolution of fibrin clots as well as in many other physiological... 相似文献