Effects of Oxygen Partial Pressure on 4-Hydroxy-2-Nonenal Induced Oxymyoglobin Oxidation

4-hydroxyl-2-nonenal (HNE) is a lipid oxidation product that can increase oxymyoglobin oxidation. However, limited research has evaluated the role of oxygen partial pressure in HNE-induced metmyoglobin formation. Therefore, the objective of was to compare the effects of atmospheric and high-oxygen partial pressure on HNE-induced oxymyoglobin oxidation in vitro. Oxymyoglobin was incubated with or without HNE at atmospheric (20% O2) or high-oxygen (80% O2) partial pressure. Metmyoglobin formation was measured after 0, 48, and 96 h of incubation at 4°C, and mass spectrometry was utilized to characterize the covalent binding of HNE to myoglobin. High-oxygen condition (80% O2) increased (P 0.05) in the extent of adduct formation. These results suggest that high-oxygen conditions had no effect on extent of HNE-binding, but can increase oxymyoglobin oxidation

Strong differences in the clonal variation of two Daphnia species from mountain lakes affected by overwintering strategy

<p>Abstract</p> <p>Background</p> <p>The population structure of cyclical parthenogens such as water fleas is strongly influenced by the frequency of alternations between sexual and asexual (parthenogenetic) reproduction, which may differ among populations and species. We studied genetic variation within six populations of two closely related species of water fleas of the genus <it>Daphnia </it>(Crustacea, Cladocera). <it>D. galeata </it>and <it>D. longispina </it>both occur in lakes in the Tatra Mountains (Central Europe), but their populations show distinct life history strategies in that region. In three studied lakes inhabited by <it>D. galeata</it>, daphnids overwinter under the ice as adult females. In contrast, in lakes inhabited by <it>D. longispina</it>, populations apparently disappear from the water column and overwinter as dormant eggs in lake sediments. We investigated to what extent these different strategies lead to differences in the clonal composition of late summer populations.</p> <p>Results</p> <p>Analysis of genetic variation at nine microsatellite loci revealed that clonal richness (expressed as the proportion of different multilocus genotypes, MLGs, in the whole analysed sample) consistently differed between the two studied species. In the three <it>D. longispina </it>populations, very high clonal richness was found (MLG/N ranging from 0.97 to 1.00), whereas in <it>D. galeata </it>it was much lower (0.05 to 0.50). The dominant MLGs in all <it>D. galeata </it>populations were heterozygous at five or more loci, suggesting that such individuals all represented the same clonal lineages rather than insufficiently resolved groups of different clones.</p> <p>Conclusions</p> <p>The low clonal diversities and significant deviations from Hardy-Weinberg equilibrium in <it>D. galeata </it>populations were likely a consequence of strong clonal erosion over extended periods of time (several years or even decades) and the limited influence of sexual reproduction. Our data reveal that populations of closely related <it>Daphnia </it>species living in relatively similar habitats (permanent, oligotrophic mountain lakes) within the same region may show strikingly different genetic structures, which most likely depend on their reproductive strategy during unfavourable periods. We assume that similar impacts of life history on population structures are also relevant for other cyclical parthenogen groups. In extreme cases, prolonged clonal erosion may result in the dominance of a single clone within a population, which might limit its microevolutionary potential if selection pressures suddenly change.</p

Effects of feeding zilpaterol hydrochloride for twenty to forty days on carcass cutability and subprimal yield of calf-fed Holstein steers

El presente trabajo de investigación se realizó con el propósito de Determinar la relación de los estilos de aprendizaje en el rendimiento académico- área de Ingles- en estudiantes de cuarto grado de secundaria del C.P.M. "San Pedro Chanel", Sullana- Piura, 2017. Para el desarrollo de la investigación se utilizó un diseño Correlacional, No Experimental Transversal, así como una población de 1700 estudiantes del nivel secundaria y una muestra No probabilística de 36 estudiantes de cuarto grado de secundaria del aula ?B?. Para la recopilación de la información se utilizó como técnica a la encuesta y como instrumento un cuestionario con escala valorativa referido a la variable Estilos de aprendizaje y para la variables Rendimiento académico se utilizó como técnica al análisis documental y como instrumento una ficha de análisis documental. La información recopilada se registró y procesó utilizando el programa SPSS V19, a partir de lo cual se presentan los resultados en tablas, así como también se realizó el análisis correlacional a través del coeficiente de Pearson. Según los resultados obtenidos existe relación moderada entre las dimensiones estilo de aprendizaje activo y estilo de aprendizaje pragmático en el rendimiento académico en los estudiantes con un coeficiente de Pearson de (0.480 y 0.561); existe relación alta entre el estilo de aprendizaje reflexivo y el rendimiento académico en los estudiantes con un coeficiente de Pearson de (0.634) y existe relación baja entre el estilo de aprendizaje teórico y el rendimiento académico en los estudiantes con un coeficiente de Pearson de (0.382).Tesi