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排序方式: 共有115条查询结果,搜索用时 15 毫秒
1.
The existence of six amylase heterogeneity variants in serum and urine has been discovered in a group of 111 families with twins, and the frequence of each variant was determined. It had been shown that each of these amylase heterogeneity variants is inherited codominantly, and the mode of inheritance is demonstrated schematically.These amylase heterogeneity variants may be used as an aid to twin zygosity determination and also in paternity problems. 相似文献
2.
Miloš Sedlák Jaromír Kaválek Vladimír Machácek Vojeslav Šterba 《Molecules and cells》1992,1(10):170-174
The cyclization reactions of N-methyl-N’-(2-methoxycarbonylphenyl)sulfamide (1a), N-methyl-N-(2-methoxycarbonylphenyl)-sulfamide (2a), and 2-methoxycarbonylphenylsulfamide (3a) were studied in aqueous amine buffers (butylamine, ethanolamine, morpholine, glycinamide). The dependences observed between the rate constants and buffer concentrations show that the reactions are subject to base catalysis in all the three cases, the decomposition of the tetrahedral intermediate being rate limiting. The ratio of the relative rate constants of the base catalyzed cyclizations reactions of the three derivatives is 1a: 2a: 3a = 1: 20000: 100. The logarithm of rate constants of the base catalyzed cyclization reactions was plotted against the pKa values of conjugated acids of the individual amines used as the buffers in the cyclization of compound 1a, and the value of the Brönsted coefficient obtained was about 0.1, which means that the proton transfer from the intermediate to the basic buffer component is thermodynamically favorable. The intermediate is a much weaker base, and the reaction is controlled by diffusion. The slope of an analogous dependence for compound 2a gradually decreases from values near to 0.5 to values near to zero, which means that the intermediate formed from compound 2a (pKa ≈ 9.3) has a pKa value comparable with that of the acid buffer component. 相似文献
3.
Jaromír Sed'a 《Hydrobiologia》1992,246(2):119-127
The diurnal periodicity of reproduction in a reservoir population of Daphnia galeata Sars was tested by two methods (egg age distribution analyses and direct observation of hatching). No significant diurnal synchronization of reproduction in the natural cladoceran population was found. A conspicuous shortage of older embryonic stages was parallely revealed by analyses of diurnal changes of egg age distribution. Suggested selective feeding of fish on gravid females of Daphnia brooding embryos with black eye pigmentation is discussed. 相似文献
4.
5.
Strunecký Otakar Kopejtka Karel Goecke Franz Tomasch Jürgen Lukavský Jaromír Neori Amir Kahl Silke Pieper Dietmar H. Pilarski Plamen Kaftan David Koblížek Michal 《Extremophiles : life under extreme conditions》2019,23(1):35-48
Extremophiles - Genotypic and morphological diversity of cyanobacteria in the Rupite hot spring (Bulgaria) was investigated by means of optical microscopy, cultivation, single-cell PCR, and 16S... 相似文献
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7.
Kulhavý D Cegan A Komers K Mindl J 《Zeitschrift für Naturforschung. C, Journal of biosciences》2002,57(5-6):496-499
The activity of every substance I inhibiting an enzymatic reaction can be approximately evaluated by the index PI50. This paper describes a simple and fast method of estimate and/ or determination of this index. The method is based on the linearity of the dependence of the ratio of reaction rates of uninhibited and inhibited reaction vs. concentration of the inhibitor at constant initial substrate and enzyme concentrations for fully competitive, noncompetitive, uncompetitive and mixed type of inhibition by the one inhibitor. The validity of the method is demonstrated by four inhibitors of hydrolysis of acetylthiocholine by butyrylcholine esterase. 相似文献
8.
Kubala M Hofbauerová K Ettrich R Kopecký V Krumscheid R Plásek J Teisinger J Schoner W Amler E 《Biochemical and biophysical research communications》2002,297(1):154-159
The ATP-binding site of Na(+)/K(+)-ATPase is localized on the large cytoplasmic loop of the alpha-subunit between transmembrane helices H(4) and H(5). Site-directed mutagenesis was performed to identify residues involved in ATP binding. On the basis of our recently developed model of this loop, Ser(445), Glu(446), and Phe(475) were proposed to be close to the binding pocket. Replacement of Phe(475) with Trp and Glu(446) with Gln profoundly reduced the binding of ATP, whereas the substitution of Ser(445) with Ala did not affect ATP binding. Fluorescence measurements of the fluorescent analog TNP-ATP, however, indicated that Ser(445) is close to the binding site, although it does not participate in binding. 相似文献
9.
Libor Fila Alžběta Grandcourtová Jaroslav Chládek Jaromír Musil 《Folia microbiologica》2014,59(3):217-222
The association between oxidative stress and neutrophilic inflammation in cystic fibrosis (CF) lung disease is well recognized. 8-Isoprostane is a product of non-enzymatic oxidation of arachidonic acid. The aim of the present study was to examine the relationship between lung function decline and 8-isoprostane concentrations in exhaled breath condensate (EBC) in CF patients with Burkholderia cenocepacia airway colonization. Concentrations of 8-isoprostane in EBC were measured in 24 stable CF patients with B. cenocepacia airway colonization. The median (interquartile range) age of the cohort was 23.9 (22.0; 26.6) years. All patients underwent clinical examinations and pulmonary function tests at the time of EBC collection and in 1-, 3-, and 5-year intervals. 8-Isoprostane concentrations in EBC correlated to 1- and 3-year declines of forced expiratory volume in 1 s (FEV1) with r S values of ?0.511 (p?=?0.0011) and ?0.495 (p?=?0.016), respectively. In multiple regression analysis, 8-isoprostane concentrations in EBC were the only independent predictor for 1-year FEV1 decline (p?=?0.01). When the median value of 8-isoprostane concentration in EBC (10.0 pg/mL) was used as a cutoff, subgroups of patients with lower and higher level of oxidative stress had significantly different median (interquartile range) FEV1 declines in 1-year interval, ?2.4 % (?5.3; 0.8) and ?7.3 % (?10.3; ?5.8) predicted (p?=?0.009). In conclusion, 8-isoprostane concentrations in EBC correlated to short-term lung function decline in CF patients with B. cenocepacia airway colonization. This correlation reflects the role of oxidative stress in CF lung pathogenesis and contributes to prediction of prognosis in these patients. 相似文献
10.
Ol’ga Vančová Ladislav Bačiak Svatava Kašparová Jarmila Kucharská Hector H. Palacios Jaromír Horecký Gjumrakch Aliev 《Journal of cellular and molecular medicine》2010,14(11):2667-2674
Brain energy disorders can be present in aged men and animals. To this respect, the mitochondrial and free radical theory of aging postulates that age‐associated brain energy disorders are caused by an imbalance between pro‐ and anti‐oxidants that can result in oxidative stress. Our study was designed to investigate brain energy metabolism and the activity of endogenous antioxidants during their lifespan in male Wistar rats. In vivo brain bioenergetics were measured using 31P nuclear magnetic resonance (NMR) spectroscopy and in vitro by polarographic analysis of mitochondrial oxidative phosphorylation. When compared to the young controls, a significant decrease of age‐dependent mitochondrial respiration and adenosine‐3‐phosphate (ATP) production measured in vitro correlated with significant reduction of forward creatine kinase reaction (kfor) and with an increase in phosphocreatine (PCr)/ATP, PCr/Pi and PME/ATP ratio measured in vivo. The levels of enzymatic antioxidants catalase, GPx and GST significantly decreased in the brain tissue as well as in the peripheral blood of aged rats. We suppose that mitochondrial dysfunction and oxidative inactivation of endogenous enzymes may participate in age‐related disorders of brain energy metabolism. 相似文献