229 research outputs found

    Reactive oxygen species and sperm cells

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    There is a dynamic interplay between pro- and anti-oxidant substances in human ejaculate. Excessive reactive oxygen species (ROS) generation can overwhelm protective mechanism and initiate changes in lipid and/or protein layers of sperm plasma membranes. Additionally, changes in DNA can be induced. The essential steps of lipid peroxidation have been listed as well as antioxidant substances of semen. A variety of detection techniques of lipid peroxidation have been summarized together with the lipid components of sperm membranes that can be subjected to stress. It is unsolved, a threshold for ROS levels that may induce functional sperm ability or may lead to male infertility

    Covalent and non-covalent in-flow biofunctionalization for capture assays on silicon chips : white light reflectance spectroscopy immunosensor combined with TOF-SIMS resolves immobilization stability and binding stoichiometry

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    Immunosensors that combine planar transducers with microfluidics to achieve in-flow biofunctionalization and assay were analyzed here regarding surface binding capacity, immobilization stability, binding stoichiometry, and amount and orientation of surface-bound IgG antibodies. Two IgG immobilization schemes, by physical adsorption [3-aminopropyltriethoxysilane (APTES)] and glutaraldehyde covalent coupling (APTES/GA), followed by blocking with bovine serum albumin (BSA) and streptavidin (STR) capture, are monitored with white light reflectance spectroscopy (WLRS) sensors as thickness dΓ of the adlayer formed on top of aminosilanized silicon chips. Multi-protein surface composition (IgG, BSA, and STR) is determined by time of flight secondary ion mass spectrometry (TOF-SIMS) combined with principal component analysis (applying barycentric coordinates to the score plot). In-flow immobilization shows at least 1.7 times higher surface binding capacity than static adsorption. In contrast to physical immobilization, which is unstable during blocking with BSA, chemisorbed antibodies desorb (reducing dΓ_{\Gamma}) only when the bilayer is formed. Also, TOF-SIMS data show that IgG molecules are partially exchanged with BSA on APTES but not on APTES/GA modified chips. This is confirmed by the WLRS data that show different binding stoichiometry between the two immobilization schemes for the direct binding IgG/anti-IgG assay. The identical binding stoichiometry for STR capture results from partial replacement with BSA of vertically aligned antibodies on APTES, with fraction of exposed Fab domains higher than on APTES/GA

    Aronia melanocarpa Treatment and Antioxidant Status in Selected Tissues in Wistar Rats

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    Aronia juice is considered to be a source of compounds with high antioxidative potential. We conducted a study on the impact of compounds in the Aronia juice on oxidative stress in plasma and brain tissues. The influence of Aronia juice on oxidative stress parameters was tested with the use of a model with a high content of fructose and nonsaturated fats. Therefore, the activity of enzymatic (catalase, CAT, and paraoxonase, PON) and nonenzymatic (thiol groups, SH, and protein carbonyl groups, PCG) oxidative stress markers, which indicate changes in the carbohydrate and protein profiles, was marked in brain tissue homogenates. Adding Aronia caused statistically significant increase in the CAT activity in plasma in all tested diets, while the PON activity showed a statistically significant increase only in case of high fat diet. In animals fed with Aronia juice supplemented with carbohydrates or fat, statistically significant increase in the PON activity and the decrease in the CAT activity in brain tissue were observed. In case of the high fat diet, an increase in the number of SH groups and a decrease in the number of PCG groups in brain tissue were observed

    The neuroprotective effect of Cornus mas on brain tissue of Wistar rats

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    Cornelian cherry (Cornus mas) is a valuable source of phenolic antioxidants. Flavonoid derivatives as nonenzymatic antioxidants are important in the pathophysiology of many diseases including neurological disorders (e.g., Alzheimer’s disease) or heart disease. In this study, we examined the effect of an addition of freeze-dried fruit of cornelian cherry on three types of diets: control diet, fructose diet, and diet enriched in fats (high-fat diet). This effect was studied by determining the following antioxidant parameters in both brain tissue and plasma in rats: catalase, ferric reducing ability of plasma, paraoxonase, protein carbonyl groups, and free thiol groups. Results indicate that both fructose diet and high-fat diet affect the antioxidant capacity of the organism. Furthermore, an addition of cornelian cherry resulted in increased activity of catalase in brain tissue, while in plasma it caused the opposite effect. In turn, with regard to paraoxonase activity in both brain tissue and plasma, it had a stimulating effect. Adding cornelian cherry to the tested diets increased the activity of PON in both tested tissues. Moreover, protective effect of fruits of this plant was observed in the process of oxidation of proteins by decreasing levels of protein carbonyl groups and thiol groups in brain tissue as well as in plasma

    Selection criteria of Zebrafish male donors for sperm cryopreservation

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    Selection criteria for sperm cryopreservation are highly relevant in zebrafish since sperm quality is particularly variable in this species. Successful cryopreservation depends on high-quality sperm, which can only be ensured by the selection of breeders. Consequently, male selection and management are a priority to improve cryopreservation, and therefore, this study aimed to characterize optimal age and sperm collection frequency in zebrafish. For this purpose, males from wild type (AB) and from a transgenic line [Tg(runx2:eGFP)] were sampled at 6, 8, 12, and 14 months. For each age, sperm were collected at time 0 followed by samplings at 2, 7, and 14 days of rest. Sperm quality was assessed according to motility and membrane viability parameters. Quality assessment showed that Tg(runx2:eGFP) displayed significantly higher motility than AB and younger males showed higher motility in both lines. Sperm collection frequency affected membrane viability. While AB fish recovered sperm viability after 14 days of rest, Tg(runx2:eGFP) could not recover. Consequently, it may be important to study the sperm quality of each zebrafish line before sperm cryopreservation. Taking into consideration the results achieved in both lines, sperm collection should be performed between 6 and 8 months of age with a minimum collection interval of 14 days.N730984, EBB-EAPA_501/2016, PEst-C/MAR/LA0015/2011info:eu-repo/semantics/publishedVersio

    Changing supersites: Assessing the impact of the southern UK EMEP supersite relocation on measured atmospheric composition

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    In January 2016 the United Kingdom's southern European Monitoring and Evaluation Programme (EMEP) level-2 air pollution monitoring 'supersite' was relocated from Harwell, Oxfordshire to Chilbolton Observatory, Hampshire. As no co-location study was undertaken, this work retrospectively investigates whether the supersite relocation has led to discontinuities in the time series of concentrations of commonly studied gaseous pollutants (NOx, NH3, SO2 and O3) and particulate matter (PM2.5 and PM10). Two years of measurements pre- and post-relocation (2014–15 and 2016–17 respectively) were analysed in conjunction with meteorological variables and local emission data. The deweather package was applied to the concatenated time series to minimise the influence of meteorology. Similar average concentrations of PM2.5, PM10, SO2 and O3 were observed, but there were substantial differences in that of NOx and NH3 (increase by factors of ~1.6 and ~3, respectively). The considerably higher NH3 concentrations at Chilbolton are attributed to the close proximity of mixed farmland, in particular to a strong south-westerly source contributing to ~50% of the annual average. NOx and PM concentrations in easterly winds arriving at Chilbolton are ~2.7 and ~1.5 times larger than at Harwell, from sources including the M3 motorway and Greater London. Westerly concentrations of NOx remain similar, therefore despite a higher frequency of westerly wind, annual mean concentrations are larger. Lower concentrations of PM arriving from the west result in similar annual averages. The secondary inorganic and black carbon components of PM were broadly similar between the sites. The differences in average NOx and NH3 at Chilbolton must be taken into account when considering long-term regional trends based on the southern UK supersite data

    4D-Var inversion of European NH3 emissions Using CrIS NH3 measurements and GEOS-Chem adjoint with bi-directional and uni-directional flux schemes

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    We conduct the first 4D-Var inversion of NH3 accounting for NH3 bi-directional flux, using CrIS satellite NH3 observations over Europe in 2016. We find posterior NH3 emissions peak more in springtime than prior emissions at continental to national scales, and annually they are generally smaller than the prior emissions over central Europe, but larger over most of the rest of Europe. Annual posterior anthropogenic NH3 emissions for 25 European Union members (EU25) are 25% higher than the prior emissions and very close (<2% difference) to other inventories. Our posterior annual anthropogenic emissions for EU25, the UK, the Netherlands, and Switzerland are generally 10%–20% smaller than when treating NH3 fluxes as uni-directional emissions, while the monthly regional difference can be up to 34% (Switzerland in July). Compared to monthly mean in-situ observations, our posterior NH3 emissions from both schemes generally improve the magnitude and seasonality of simulated surface NH3 and bulk NHx wet deposition throughout most of Europe, whereas evaluation against hourly measurements at a background site shows the bi-directional scheme better captures observed diurnal variability of surface NH3. This contrast highlights the need for accurately simulating diurnal variability of NH3 in assimilation of sun-synchronous observations and also the potential value of future geostationary satellite observations. Overall, our top-down ammonia emissions can help to examine the effectiveness of air pollution control policies to facilitate future air pollution management, as well as helping us understand the uncertainty in top-down NH3 emissions estimates associated with treatment of NH3 surface exchange
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