446 research outputs found

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    Developing and Optimizing RNA Isolation Methods from Avian Tissues

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    Investigating tissue-specific gene expression first requires RNA isolation. This research seeks to develop and optimize multiple methods of RNA extraction from blood and gonadal tissues in several different avian species, including house sparrows (Passer domesticus) and northern jacanas (Jacana spinosa). Method variations include RNAlater vs. flash freezing tissue, homogenizer vs. bashing beads, phase separation vs. Zymo kit, and various temperature and time settings for incubation. Establishing effective methods for avian investigation of RNA will allow us to research how differential gene expression relates to phenotypic behaviors

    A Differential Redox Regulation or the Pathways Metabolizing Glyceraldehyde-3-phosphate Tunes the Production of Reducing Power in the Cytosol of Plant Cells

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    Adaptation to aerobic life leads organisms to sense reactive oxygen species and use the signal for coordination of the entire metabolism. Glycolysis in plants is a particular network where specific steps, like oxidation of glyceraldehydes-3-phosphate (Ga3P), are critical in order for it to function. The triose-phosphate can be converted into 3-phosphoglycerate through the phosphorylating Ga3P dehydrogenase (Ga3PDHase, EC 1.2.1.12) producing ATP and NADH, or via the non-phosphorylating enzyme (np-Ga3PDHase; EC 1.2.1.9) generating NADPH. In this work we found redox regulation to be a posttranslational mechanism allowing the fine-tuning of the triose-phosphate fate. Both enzymes were inactivated after oxidation by reactive oxygen and nitrogen species. Kinetic studies determined that Ga3PDHase is marked (63-fold) more sensitive to oxidants than np-Ga3PDHase. Thioredoxin-h reverted the oxidation of both enzymes (although with differences between them), suggesting a physiological redox regulation. The results support a metabolic scenario where the cytosolic triose-phosphate dehydrogenases are regulated under changeable redox conditions. This would allow coordinate production of NADPH or ATP through glycolysis, with oxidative signals triggering reducing power synthesis in the cytosol. The NADPH increment would favor antioxidant responses to cope with the oxidative situation, while the thioredoxin system would positively feedback NADPH production by maintaining np-Ga3PDHase at its reduced active state.Fil: Piattoni, Claudia Vanesa. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico - CONICET - Santa Fe. Instituto de Agrobiotecnologia del Litoral; Argentina;Fil: Guerrero, Sergio Adrian. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico - CONICET - Santa Fe. Instituto de Agrobiotecnologia del Litoral; Argentina;Fil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico - CONICET - Santa Fe. Instituto de Agrobiotecnologia del Litoral; Argentina

    Space-based optical observation system suitable for micro satellite

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    The PhD research activity has taken place in the space debris field. In detail, it is focused on the possibility of detecting space debris from the space based platform. The research is focused at the same time on the software and the hardware of this detection system. For the software, a program has been developed for being able to detect an object in space and locate it in the sky solving the star field. For the hardware, the possibility of adapting a ground telescope for space activity has been considered and it has been tested on a possible electronic board

    Seismic Design and Preliminary Analyses of a Prefabricated Hybrid Steel-Concrete Wall

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    Steel frames with reinforced concrete infill walls (SRCWs) are an interesting structural solution for applications in seismic areas if designed to exploit the stiffness of reinforced concrete (RC) and the ductility and dissipative capacity of steel. Three horizontal resisting mechanisms can be identified in SRCW: 1) contribution of the steel frame; 2) direct interactions between the steel frame and the compression strut in the RC infill walls; 3) interactions between steel frame and the RC infill wall through friction and shear connectors. While Eurocode 8 considers SRCWs to behave essentially as RC walls, numerical analyses demonstrated that this assumption may be far from reality. Innovative solutions for SRCW and relevant design approaches were eventually proposed in order to achieve a structural system able to fully exploit the advantages of the steel and RC components. In this context, the present study investigates a type of innovative modular SRCW through numerical simulations allowing a better understanding of its structural behaviour

    Multimodal models of animal sex in scientific literature: breaking binaries leads to a better understanding of ecology and evolution

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    ‘Sex’ is often used to describe a suite of phenotypic and genotypic traits of an organism related to reproduction. However, not all these traits are necessarily linked, and the rhetorical collapse of variation into a single term elides much of the complexity inherent in reproductive phenotypes. We conducted a meta-analysis of scientific literature to investigate how terminology related sexual phenotypes changes over time. We find that the conflation of gender and sex has increased, and there is a mammalian bias in this conflation. We highlight how a more inclusive and expansive framework for sex can clarify studies of sexual diversity

    Methane output of rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus) fed a hay-only diet: Implications for the scaling of methane production with body mass in non-ruminant mammalian herbivores

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    It is assumed that small herbivores produce negligible amounts of methane, but it is unclear whether this is a physiological peculiarity, or simply a scaling effect. A respiratory chamber experiment was conducted with six rabbits (Oryctolagus cuniculus, 1.57 ± 0.31 kg body mass) and six guinea pigs (Cavia porcellus, 0.79 ± 0.07 kg) offered grass hay ad libitum. Daily dry matter (DM) intake and DM digestibility were 50 ± 6 g kg–0.75 d–1 and 55 ± 6 % in rabbits and 59 ± 11 g kg–0.75 d–1 and 61 ± 3 % in guinea pigs, respectively. Methane production was similar for both species (0.20 ± 0.10 L d–1 and 0.22 ± 0.08 L d–1) and represented 0.69 ± 0.32 and 1.03 ± 0.29 % of gross energy intake in rabbits and guinea pigs, respectively. In relation to body mass (BM) guinea pigs produced significantly more methane. The data on methane per unit of BM obtained in this study and from literature on methane output of elephant, wallabies and hyraxes all lay close to a regression line derived from roughage-fed horses, showing an increase in methane output with BM. The regression including all data was nearly identical to that based on the horse data only (methane production in horses [L d–1] = 0.18 body mass [kg]0.97 (95%CI 0.92–1.02)) and indicates linear scaling. Because feed intake typically scales to BM0.75, linear scaling of methane output translates into increasing energetic losses at increasing BM. Accordingly, the data collection indicates that an increasing proportion of ingested gross energy is lost because relative methane production increases with BM. Different from ruminants, such losses (1-2% of gross energy) appear too small in non-ruminant herbivores to represent a physiologic constraint on body size. Nevertheless, this relationship may represent a physiological disadvantage with increasing herbivore body size

    Assessment of seismic vulnerability of historical defensive walls

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    This paper presents a study on the behaviour of the walls of the Rocca Roveresca of Senigallia in Italy built in the XIV century on the ruins of a former Roman defensive struc-ture. This is a peculiar example of a small fortress that had undergone in the XV century im-portant modifications of the plant in order to enhance its defensive performances. A linear finite element model is first developed in order to understand the dynamic behaviour of a ge-neric portion of the wall and to detect the probable incipient failure mechanisms. A subse-quent static nonlinear analysis is carried out, with the same finite element model, to investigate the formation of the cracking layout and to detect the position of plastic hinges. The last analysis level is carried out with a tailored macro-element constituted by three bod-ies, namely the two external curtains and the inner fill for which a degradation of the behav-iour is considered. The results obtained demonstrates the efficiency of the wall against earthquakes characterized by return times typical for ultimate limit states. Same issues that deserve further investigation are highlighted

    Please, sir, pull down your socks!

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    A 48-year-old male patient presented at the regular followupvisit seven months after a successful kidney transplant.After discussion of blood chemistries with the doctor, thepatient underwent a physical examination. As usual, heunbuttoned his shirt and undid his trouser belt. Inspectionof the limbs, after pulling up his trousers, confirmed thepresence of ankle oedema; the graft was quite firm, with nomurmurs in the area

    Redox Regulation of UDP-glucose Pyrophosphorylase from Entamoeba histolytica.

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    Amoebiasis is an intestinal infection caused by the human pathogen Entamoeba histolytica and representing the third leading cause of death by parasites in the world. Host-parasite interactions mainly involve anchored glycoconjugates localized in the surface of the parasitic cell. In protozoa, synthesis of structural oligo- and polysaccharides occurs via UDP-glucose, generated in a reaction catalyzed by UDP-glucose pyrophosphorylase. We report the molecular cloning of the gene coding for this enzyme from genomic DNA of E. histolytica and its recombinant expression in Escherichia coli cells. The purified enzyme was kinetically characterized, catalyzing UDP-glucose synthesis and pyrophosphorolysis with V(max) values of 95 U/mg and 3 U/mg, respectively, and affinity for substrates comparable to those found for the enzyme from other sources. Enzyme activity was affected by redox modification of thiol groups. Different oxidants, including diamide, hydrogen peroxide and sodium nitroprusside inactivated the enzyme. The process was completely reverted by reducing agents, mainly cysteine, dithiothreitol, and thioredoxin. Characterization of the enzyme mutants C94S, C108S, C191S, C354S, C378S, C108/378S, M106S and M106C supported a molecular mechanism for the redox regulation. Molecular modeling confirmed the role of specific cysteine and methionine residues as targets for redox modification in the entamoebic enzyme. Our results suggest that UDP-glucose pyrophosphorylase is a regulated enzyme in E. histolytica. Interestingly, results strongly agree with the occurrence of a physiological redox mechanism modulating enzyme activity, which would critically affect carbohydrate metabolism in the protozoon.Fil: Martínez, Lucila Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Piattoni, Claudia Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Garay, Alberto. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; ArgentinaFil: Rodrigues, Daniel Enrique. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Guerrero, Sergio Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentin
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