988 resultados para Adenosine triphosphatase activity


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The characteristics of an in vitro polyuridylic acid dependent amino acid incorporating system prepared from germinating macroconidia of Microsporum canis are described. The incorporation of 14C-phenylalanine into polyphenylalanine is dependent on S-30 extract, adenosine triphosphate, magnesium ions and polyuridylic acid. Incorporation is slightly enhanced by yeast transfer ribonucleic acid and pyruvate kinase. The system is highly sensitive to ribonuclease, puromycin and miconazole (an antifungal agent), moderately sensitive to sodium fluoride and much less sensitive to phenethylalcohol, cycloheximide, chloramphenicol and deoxyribonuclease. Cell-free extract from ungerminated conidia has less capacity to synthesize the protein and during germination a marked increase in the protein synthetic activity is observed. The results from experiments wherein ribosomes and S-100 fraction from germinated and ungerminated spores are interchanged, revealed that the defect in the extract from the ungerminated spore is in the ribosomes.

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Dendrite Pd with corrugated surfaces, obtained by a novel AC technique, exhibits an exceptionally high catalytic activity for the oxidation of formic acid because of the presence of a high density of surface steps. The formation of twinned dendrites leads to a predominance of exposed 111 facets with a high density of surface steps as evident from high resolution electron microscopy investigations. These surface sites provide active sites for the absorption of the formic acid molecules, thereby enhancing the reaction rate. Control experiments by varying the time of deposition reveal the formation of partially grown dendrites at shorter times indicating that the dendrites were formed by growth rather than particle attachment. Our deposition method opens up interesting possibilities to produce artisotropic nanostructures with corrugated surfaces by exploiting the perturbations involved in the growth process.

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The crystal and molecular structures of the Tris salt of adenosine 5'-diphosphate were determined from X-ray diffraction data. The crystals are monoclinic, space P21, and Z = 2 with a=9.198 (2) A, b=6.894 (1) A, c=18.440 (4) A, and beta = 92.55 (2) degrees. Intensity data were collected on an automated diffractometer. The structure was solved by the heavy-atom technique and refined by least squares to R = 0.047. The ADP molecule adopts a folded conformation. The conformation about the glycosidic bond is anti. The conformation of the ribose ring is close to a perfect C(2')-endo-C-(3')-exo puckering. The conformation about C(4')-C(5') is gauche-gauche, similar to other nucleotide structures. The pyrophosphate chain displays a nearly eclipsed geometry when viewed down the P-P vector, unlike the staggered conformation observed in crystal structures of other pyrophosphates. The less favorable eclipsed conformation probably results from the observed association of Tris molecules with the polar diphosphate chain through electrostatic interactions and hydrogen bonds. Such interactions may play an important role in Tris-buffered aqueous solutions of nucleotides and metal ions.

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M.A. (Educ.) Anu Kajamaa from the University of Helsinki, Center for Research on Activity, Development and Learning (CRADLE), examines change efforts and their consequences in health care in the public sector. The aim of her academic dissertation is, by providing a new conceptual framework, to widen our understanding of organizational change efforts and their consequences and managerial challenges. Despite the multiple change efforts, the results of health care development projects have not been very promising, and many developmental needs and managerial challenges exist. The study challenges the predominant, well-framed health care change paradigm and calls for an expanded view to explore the underlying issues and multiplicities of change efforts and their consequences. The study asks what kind of expanded conceptual framework is needed to better understand organizational change as transcending currently dominant oppositions in management thinking, specifically in the field of health care. The study includes five explorative case studies of health care change efforts and their consequences in Finland. Theory and practice are tightly interconnected in the study. The methodology of the study integrates the ethnography of organizational change, a narrative approach and cultural-historical activity theory. From the stance of activity theory, historicity, contradictions, locality and employee participation play significant roles in developing health care. The empirical data of the study has mainly been collected in two projects, funded by the Finnish Work Environment Fund. The data was collected in public sector health care organizations during the years 2004-2010. By exploring the oppositions between distinct views on organizational change and the multi-site, multi-level and multi-logic of organizational change, the study develops an expanded, multidimensional activity-theoretical framework on organizational change and management thinking. The findings of the study contribute to activity theory and organization studies, and provide information for health care management and practitioners. The study illuminates that continuous development efforts bridged to one another and anchored to collectively created new activity models can lead to significant improvements and organizational learning in health care. The study presents such expansive learning processes. The ways of conducting change efforts in organizations play a critical role in the creation of collective new practices and tools and in establishing ownership over them. Some of the studied change efforts were discontinuous or encapsulated, not benefiting the larger whole. The study shows that the stagnation and unexpected consequences of change efforts relate to the unconnectedness of the different organizational sites, levels and logics. If not dealt with, the unintended consequences such as obstacles, breaks and conflicts may stem promising change and learning processes.

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Exposure of cold-acclimatized rats to heat (37 degrees C) for a short period decreased brown adipose tissue (BAT) mitochondrial substrate-dependent oxygen uptake and H2O2 generation. Both the concentration and substrate-dependent rate of cytochrome b reduction decreased as early as 3 h of heat exposure. These results identify cytochrome b as the locus of regulation of electron transport in BAT mitochondria under conditions of heat stress.

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The Developmental Origins of Health and Disease Hypothesis proposes that adverse health outcomes in adult life are in part programmed during fetal life and infancy. This means that e.g. restricted nutrition during pregnancy programmes the offspring to store fat more effectively, to develop faster and to reach puberty earlier. These adaptations are beneficial in terms of short term survival. However, in developed countries these adaptations often lead to an increased risk of obesity and metabolic disturbances in later life, due to a mismatch between the prenatal and postnatal environment. This thesis aimed to study the role of early growth in people who are obese as adults, but metabolically healthy as well as in those who are normal in weight but metabolically obese. Other study aims were to assess whether physical activity and cardiorespiratory fitness are programmed early in life. The role of socioeconomic status in the development of obesity from a life course setting was also studied. These studies included 2003 men and women born in Helsinki between 1934 and 1944 with detailed information of their prenatal and childhood growth as well as living conditions. They participated in the detailed clinical examination during the years 2001-2004. A sub-group of the subjects participated in the UKK Institute 2-kilometre walk test. Metabolic syndrome was defined according to the 2005 criteria of the International Diabetes Federation. Among the obese men and women 20 % were metabolically healthy. Those with metabolic syndrome did not differ in birth size compared to the healthy ones, but by two years of age, they were lighter and thinner, and remained so up to 11 years. The period when changes in BMIs were predictive of the metabolic syndrome was from birth to 7 years. Of the normal weight individuals 17 % were metabolically obese. Again, there were no differences in birth size. However, by the age 7 years, those men who later developed metabolic syndrome were thinner. Gains in BMI during the first two years of life were protective of the syndrome. Children who were heavier, and especially taller, were more physically active, exercised with higher intensity and had higher cardiorespiratory fitness in their adult life than those who were shorter and thinner as children. Lower educational attainment and lower adult social class were associated with obesity in both men and women. Childhood social class was inversely associated with body mass index only in men while lower household income was associated with higher BMI in women. These results support the role of early life factors in the development of metabolic syndrome and adult life style. Early detection of risk factors predisposing to these conditions is highly relevant from a public health point of view.

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Soil properties and their behavior, apart from stress history, are influenced markedly by physicochemical characteristics of the constituent clay and nonclay minerals and their relative proportions. Atterberg limits and Skempton’s colloidal activity, which are simple quantitative parameters, reflect the composite effects of the soil constituents and their interactions with pore fluid. Micromechanistic interpretations of these parameters have been provided in this paper. It has been shown that, in general, the liquid limit of fine-grained soils reflects the physicochemical potential and that each of the factors of Skempton’s colloidal activity are interdependent. It has been illustrated that property correlations with colloidal activity, as well as with Atterberg limits, result in involved interrelationships due to the interdependence of the parameters.

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Soil properties and their behavior, apart from stress history, are influence markedly by physicochemical characteristics of the constituent clay and nonclay minerals and their relative proportions. Atterberg limits and Skempton's colloidal activity, which are simple quantitative parameters, reflect the composite effects of the soil constituents and their interactions with pore fluid. Micromechanistic interpretations of these parameters have been provided in this paper. It has been shown that, in general, the liquid limit of fine-grained soils reflects the physicochemical potential and that each of the factors of Skempton's colloidal activity are interdependent. It has been illustrated that property correlations with colloidal activity, as well as with Atterberg limits, result in involved interrelationships due to the interdependence of the parameters.

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The aim of the present study was to examine the effect of hemiorchidectomy (HO) on serum FSH, LH, testosterone (T), and inhibin (INH) concentrations as well as on the testicular volume (TV) and on changes in the kinetics of germ cell turnovers in the remaining testis of adult male bonnet monkeys. Blood samples collected at 2200 h at various times before and after HO and testicular biopsies obtained at different periods were subjected to hormone analysis and DNA flow cytometry. Though serum T levels were lowered (p < 0.05) at 12 h after HO, T levels rapidly returned to intact control concentrations by Day 5. While serum LH remained unaltered, serum FSH increased markedly within 2 days of HO and remained significantly (p < 0.05) elevated over the next 90 days. Though serum INH showed a significant decrease (p < 0.05) by 15 min of HO, it returned to approximately 80% of intact levels within one week. The TV of the remaining testis showed maximal increment by Day 30 (p < 0.05) of HO. DNA flow cytometric analysis 24 days after HO showed increases (p < 0.05) in spermatogonia (2C) and primary spermatocytes (4C). These cell types by Day 45 had transformed to round (1C) and elongate (HC) (by 38%, p < 0.001) spermatids. Overall spermatogenesis (conversion of 2C to 1C and HC) showed significant enhancement at Days 110 and 175, suggesting that the spurt in spermatogenic activity is not confined to a single spermatogenic cycle.

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Multiple forms of beta-glucosidase (EC 3.2.1.21) of Sporotrichum thermophile were produced when the fungus was grown in a cellulose medium. One beta-glucosidase was purified 16-fold from 6-d-old culture filtrates by ion-exchange and gel-filtration chromatography. The purified enzyme was free of cellulase activity. It hydrolysed aryl beta-D-glucosides and beta-D-linked diglucosides. It was optimally active at pH 5.4, at 65-degrees-C. The apparent K(m) values for p-nitrophenyl beta-D-glucoside (PNPG) and cellobiose were 0.29 and 0.83 mm, respectively. Glucose, fucose, nojirimycin and gluconolactone inhibited beta-glucosidase competitively. At high (> 1 mm) substrate concentration, beta-glucosidase catalysed a parallel transglycosylation reaction. The transglycosylation product formed from cellobiose appeared to be a beta-linked tetramer of glucose. Admixtures of beta-glucosidase and cellulase components showed that the concept of cellobiose inhibition of cellulases was not valid for all components of the cellulase system of S. thermophile. Beta-Glucosidase supplementation also stimulated cellulose hydrolysis by cellulases when there was no accumulation of cellobiose in reaction mixture.

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Objective: The present study is to evaluate the antiulcer effect of hydroalcoholic (70%) extract of Terminalia chebula fruit. Materials and methods: Aspirin, ethanol and cold restraint stress-induced ulcer methods in rats were used for the study. The effects of the extract on gastric secretions, pH, total and free acidity using pylorus ligated methods were also evaluated. Results: Animals pretreated with doses of 200 and 500 mg/kg hydroalcoholic extract showed significant reduction in lesion index, total affected area and percentage of lesion in comparison with control group (P < 0.05 and P < 0.01) in the aspirin, ethanol and cold restraint stress-induced ulcer models. Similarly extracts increased mucus production in aspirin and ethanol-induced ulcer models. At doses of 200 and 500 mg/kg of T. chebula extract showed antisecretory activity in pylorus ligated model, which lead to a reduction in the gastric juice volume, free acidity, total acidity, and significantly increased gastric pH. Discussion and conclusion: These findings indicate that hydroalcoholic extract of the fruit T. chebula displays potential antiulcerogenic activity. This activity thus lends pharmacological credence to the suggested use of the plant as a natural remedy in the treatment or management of ulcer.