PAR modulation of the UV-dependent levels of flavonoid metabolites in Arabidopsis thaliana (L.) Heynh. leaf rosettes: Cumulative effects after a whole vegetative growth period.

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    Long-term effects of ultraviolet (UV) radiation on flavonoid biosynthesis were investigated in Arabidopsis thaliana using the sun simulators of the Helmholtz Zentrum München. The plants, which are widely used as a model system, were grown (1) at high photosynthetically active radiation (PAR; 1,310 micromol m(-2) s(-1)) and high biologically effective UV irradiation (UV-B(BE) 180 mW m(-2)) during a whole vegetative growth period. Under this irradiation regime, the levels of quercetin products were distinctively elevated with increasing UV-B irradiance. (2) Cultivation at high PAR (1,270 micromol m(-2) s(-1)) and low UV-B (UV-B(BE) 25 mW m(-2)) resulted in somewhat lower levels of quercetin products compared to the high-UV-B(BE) conditions, and only a slight increase with increasing UV-B irradiance was observed. On the other hand, when the plants were grown (3) at low PAR (540 micromol m(-2) s(-1)) and high UV-B (UV-B(BE) 180 mW m(-2)), the accumulation of quercetin products strongly increased from very low levels with increasing amounts of UV-B but the accumulation of kaempferol derivatives and sinapoyl glucose was less pronounced. We conclude (4) that the accumulation of quercetin products triggered by PAR leads to a basic UV protection that is further increased by UV-B radiation. Based on our data, (5) a combined effect of PAR and different spectral sections of UV radiation is satisfactorily described by a biological weighting function, which again emphasizes the additional role of UV-A (315-400 nm) in UV action on A. thaliana

    Quality assurance in digital volume tomography.

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    Digital Volume Tomography is a method of rising value in dentistry as well as in oral and maxillofacial surgery. The different systems commercially available offer a variety of characteristics due to their different construction and the different reconstruction algorithms in use. Especially the missing possibilities to export raw data linearly and the fact that there is no common output scale like the Hounsfield scale in computed tomography make it difficult to evaluate images of test phantoms in a unified way. We present measurements of resolution, homogeneity, contrast to noise ratio and modulation transfer function from datasets built from a test phantom by different commercial systems. The results are connected to dose measurements and the comparability of results from different systems is discussed as well as the possibility of statements about differences in their efficiency

    Physical activity and the metabolic syndrome in elderly German men and women: Results from the population-based KORA survey.

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    The purpose of this study is to determine the optimal duration and intensity of exercise for elderly people for the prevention of the metabolic syndrome. RESEARCH DESIGN AND METHODS - The population-based Cooperative Research in the Region of Augsburg (KORA) S4 Survey with 1,653 participants aged 55-74 years was used to investigate the relationship between the metabolic syndrome and physical activity. RESULTS - Fifty-seven percent of men and 48% of women showed clinical symptoms of the metabolic syndrome. Leisure activities were common (>80% walked >30 min/day). Sports activities performed regularly for : <= 1 h per week reduced file odds of having the metabolic (odds ratio 0.70 [95% CI 0.49-1.02] for men and 0.74 [0.53-1.04] for women), and sports activities >2 h per week were even more effective (0.62 [0.42-0.92] for men and 0.59 [039-0.89] for women). In contrast, activities such as walking and cycling did not have an additional influence. CONCLUSIONS - Intense physical activity by the elderly should be promoted in addition to leisure physical activity for the prevention of the metabolic syndrome

    Finite-dimensional attractors and exponential attractors for degenerate doubly nonlinear equations.

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    We consider the following doubly nonlinear parabolic equation in a bounded domain Omega subset of R-3: f (x, partial derivative(t)u) = Delta(x)u - g (x, u) where the nonlinearity f is allowed to have a degeneracy with respect to partial derivative(t)u of the form partial derivative(t)u vertical bar partial derivative(t)u vertical bar(p) at some points x is an element of Omega. Under some natural assumptions on the nonlinearities f and g, we prove the existence and uniqueness of a solution of that problem and establish the finite-dimensionality of global and exponential attractors of the semigroup associated with this equation in the appropriate phase space

    Increase of inflammatory markers after indoor renovation activities: The LISA birth cohort study.

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    There is concern about indoor air quality as a possible cause for health impairment. Exposure to indoor renovation activities has been shown to be associated with airway symptoms and allergic manifestations in children. The aim of this study is to analyse immune markers responsible for disease development in relation to renovation activities. Within the LISAplus (Life style Immune System Allergy) birth cohort study, blood samples of 6-yr-old children were analysed for concentration of the inflammatory markers interleukin (IL)-8, IL-6, tumour necrosis factor-alpha, MCP-1 and IL-10. Data on indoor renovation activities (painting, flooring, new furniture) were assessed with a questionnaire filled in by the parents. Data on cytokine blood concentrations and exposure variables were available for 250 children. Increased levels of IL-8 and MCP-1 in children's blood were related to renovation activities. In particular, new floor covering was associated with increased inflammatory markers. Among floor covering materials only wall-to-wall carpets were associated with elevated IL-8 and Monocyte Chemoattractant Protein-1 (MCP-1) levels. No association between the single renovation activities painting and furnishing and blood concentration of inflammatory markers has been found. Our data shows that IL-8 and MCP-1 may be suitable markers for monitoring inflammatory reactions in relation with renovation activities. Among renovation activities floor covering seems to induce the strongest inflammatory reactions

    Comparison of predicted and experimental subcellular localization of two putative rat steroid dehydrogenases from the short-chain dehydrogenase/reductase protein superfamily.

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    In the characterization of newly identified proteins, subcellular localization studies can provide important hints to the proteins' metabolic functions. Depending on the biochemical task of an enzyme, certain subcellular environmental conditions as pH or availability of cofactors and substrates have to be fulfilled. Consequently, misdirected proteins often cannot conduct the proper chemical reaction. This study is aimed at detecting differences in bioinformatic and wet lab experiments and presenting ways for reliable analysis of subcellular localization. On a set of ten enzymes from the short-chain dehydrogenase/reductase (SDR) superfamily, we have performed predictions and experimental analyses of subcellular localization. Exemplarily, we show the localization studies on rat short-chain dehydrogenases/reductases dhrs7b and dhrs8. We demonstrate in particular that all of the prediction algorithms tested failed to assign the SDR enzymes to an experimentally verified subcellular compartment

    The role of UDP-glucose: Hydroxycinnamate glucosyltransferases in phenylpropanoid metabolism and the response to UV-B radiation in Arabidopsis thaliana.

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    Arabidopsis harbors four UDP-glycosyltransferases that convert hydroxycinnamates (HCAs) to 1-O-beta-glucose esters, UGT84A1 ( encoded by At4g15480), UGT84A2 (At3g21560), UGT84A3 (At4g15490), and UGT84A4 (At4g15500). To elucidate the role of the individual UGT84A enzymes in planta we analyzed gene expression, UGT activities and accumulation of phenyl-propanoids in Arabidopsis wild type plants, ugt mutants and overexpressing lines. Individual ugt84A null alleles did not significantly reduce the gross metabolic flux to the accumulating compounds sinapoylcholine (sinapine) in seeds and sinapoylmalate in leaves. For the ugt84A2 mutant, LC/MS analysis revealed minor qualitative and quantitative changes of several HCA choline esters and of disinapoylspermidine in seeds. Overexpression of individual UGT84A genes caused increased enzyme activities but failed to produce significant changes in the pattern of accumulating HCA esters. For UGT84A3, our data tentatively suggest an impact on cell wall-associated 4-coumarate. Exposure of plants to enhanced UV-B radiation induced the UGT84A-encoding genes and led to a transient increase in sinapoylglucose and sinapoylmalate concentrations
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