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V V Kakubava A A Trots E K Dzhikidze Z K Stasilevich 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1990,(12):10-12
A new, cheaper and more sensitive method for the quantitative determination of DNAase produced by S. aureus is described. The method permits the determination of DNAase activity in a wider range of titers. The method is based on the detection of the depolymerizing action of staphylococcal nuclease on DNA dyed with ethidium bromide. In this work 22 S. aureus strains isolated from monkeys and 12 strains isolated from humans have been used. The amount of produced by these strains has been determined. The DNAase results of this determination have shown that among S. aureus strains isolated from monkeys and humans the occurrence of strains with both high and low DNAase activity can be observed. 相似文献
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Stefano Girotti Cinzia Bassoli Maria Loredana Cascione Severino Ghini Giacomo Carrea Roberto Bovara Aldo Roda Roberto Motta Roberto Petilino 《Luminescence》1989,3(2):41-45
The catalytic activity of serum L -lactate dehydrogenase (LDH), was determined by monitoring the NADH produced by LDH with bacterial bioluminescent enzymes immobilized on a nylon coil. The LDH reaction of L -lactate with NAD took place in a flow-through mixing coil that preceded the bioluminescent detector coil. The response was linear from 1 to 5000 U/l at 37°C and from 3 to 2000 U/l at 25°C. The intra- and inter-assay reproducibility (CV%) were less than 10% and recovery range was 92% to 110%. The results agreed well with those obtained with a spectrophotometric method. 相似文献
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A radioimmunoassay (RIA) capable of quantitating dCTP in femtomolar amounts in cell extracts has been developed, and applied to human fibroblast cell lines and L5178Y mouse lymphoma lines. Cross reactivity of the antibody with CTP, though low (2.7%) has necessitated pre-RIA removal of CTP by either boronate affinity gel chromatography or sodium periodate oxidation. Fractions from the boronate gel column or aliquots of NaIO4-treated cell extract are quantitated directly by the RIA. Recovery of extracted dCTP standard taken through the entire procedure is quantitative and results are reproducible. Due to the high sensitivity of the quantitation step, dCTP can be accurately measured in relatively small numbers of cells--about 10(4) cells. 相似文献
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Summary A histochemical technique was developed for the quantitative determination of succinic dehydrogenase (SDH) activity in muscle cross-sections using 1-methoxyphenazine methosulphate (mPMS) as the exogenous electron carrier, and azide as an inhibitor of cytochrome oxidase. The optimal composition of the incubation medium for the SDH reaction was determined. This histochemical procedure was compared to one using phenazine methosulphate (PMS) instead of mPMS and cyanide instead of azide. The substitution of mPMS and azide resulted in a substantial decrease in the non-specific reduction of nitroblue tetrazolium (NBT; the reaction indicator), i.e., nothing dehydrogenase activity. With mPMS and azide in the reaction medium, the production of NBT formazan was linear for at least 9 min during the enzymic reaction. This compared to a non-linear reduction of NBT during the initial stages of the reactions (SDH and nothing dehydrogenase) when using PMS and cyanide. The use of both mPMS and azide also eliminated the production of NBT monoformazan which occurred with PMS and cyanide. This procedure was shown to meet various criteria established for the quantification of histochemical reactions. 相似文献
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H L Goldsmith 《The Journal of general physiology》1968,52(1):5Suppl-5Su28s
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The freezing of human kidney cell suspensions 总被引:2,自引:0,他引:2
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Importance of glucose-6-phosphate dehydrogenase activity in cell death 总被引:12,自引:0,他引:12
Tian Wang-Ni; Braunstein Leigh D.; Apse Kira; Pang Jiongdong; Rose Mark; Tian Xiaoni; Stanton Robert C. 《American journal of physiology. Cell physiology》1999,276(5):C1121
The intracellular redox potential plays an important role incell survival. The principal intracellular reductant NADPH is mainlyproduced by the pentose phosphate pathway by glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme, and by6-phosphogluconate dehydrogenase. Considering the importance of NADPH,we hypothesized that G6PDH plays a critical role in cell death. Ourresults show that 1) G6PDHinhibitors potentiatedH2O2-inducedcell death; 2) overexpression ofG6PDH increased resistance toH2O2-induced cell death; 3) serum deprivation, astimulator of cell death, was associated with decreased G6PDH activityand resulted in elevated reactive oxygen species (ROS);4) additions of substrates for G6PDHto serum-deprived cells almost completely abrogated the serumdeprivation-induced rise in ROS; 5)consequences of G6PDH inhibition included a significant increase inapoptosis, loss of protein thiols, and degradation of G6PDH; and6) G6PDH inhibition caused changesin mitogen-activated protein kinase phosphorylation that were similarto the changes seen withH2O2.We conclude that G6PDH plays a critical role in cell death by affectingthe redox potential. 相似文献
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Scott K. Powers Fu-Kong Lieu David Criswell Stephen Dodd 《The Histochemical journal》1993,25(7):491-496
Summary The purpose of this investigation was to examine critically the validity of a computerized quantitative microphotometric histochemical technique for the determination of succinate dehydrogenase (SDH) activity in skeletal muscle fibres. Sections from the anterior costal diaphragm were removed from Fischer-344 rats (n = 12) and assayed histochemically to determine SDH activity. The SDH activity in individual muscle fibres was computed using a computerized microphotometric histochemical technique which involves measurement of the optical density of deposited diformazan derived from nitroblue tetrazolium within the fibres. To validate the histochemical technique, whole muscle SDH activities were calculated from the histochemical procedure and were compared to SDH activities determined from whole muscle homogenates via a standard quantitative biochemical assay. The mean within-day variability of the computerized microphotometric histochemical technique of determining SDH activity was 6% (range = 0.5–10.9%) for an area containing ~50 fibres and 6.1% (range = 1.05–14.9%) for an individual muscle fibre. Similarly, the mean between-day variability of the microphotometric histochemical technique of determining SDH activity was 5.9% (range = 2.6–13.9%) for an area containing ~50 fibres and 6.6% (range = 2.2–13.9%) for an individual muscle fibre. The inter-class correlation coefficient between biochemically determined SDH activity and histochemically determined SDH activity was r = 0.83 (p < 0.05). Collectively, these data demonstrate that the quantitative histochemical technique of Blanco et al. (1988) is both valid and reliable in the determination of SDH activity in skeletal muscle fibres. 相似文献
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Aspartase activity of cell free extracts prepared from aged cell suspensions of Bacterium cadaveris 总被引:1,自引:1,他引:0
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WILLIAMS VR 《Journal of bacteriology》1957,74(3):410-411
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Poulsson E 《The Biochemical journal》1928,22(1):135-141