20 research outputs found

    Assessing Tn5 and sleeping beauty for transpositional transgenesis by cytoplasmic injection into bovine and ovine zygotes

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    Transgenic domestic animals represent an alternative to bioreactors for large-scale production of biopharmaceuticals and could also provide more accurate biomedical models than rodents. However, their generation remains inefficient. Recently, DNA transposons allowed improved transgenesis efficiencies in mice and pigs. In this work, Tn5 and Sleeping Beauty (SB) transposon systems were evaluated for transgenesis by simple cytoplasmic injection in livestock zygotes. In the case of Tn5, the transposome complex of transposon nucleic acid and Tn5 protein was injected. In the case of SB, the supercoiled plasmids encoding a transposon and the SB transposase were co-injected. In vitro produced bovine zygotes were used to establish the cytoplasmic injection conditions. The in vitro cultured blastocysts were evaluated for reporter gene expression and genotyped. Subsequently, both transposon systems were injected in seasonally available ovine zygotes, employing transposons carrying the recombinant human factor IX driven by the beta-lactoglobulin promoter. The Tn5 approach did not result in transgenic lambs. In contrast, the Sleeping Beauty injection resulted in 2 lambs (29%) carrying the transgene. Both animals exhibited cellular mosaicism of the transgene. The extraembryonic tissues (placenta or umbilical cord) of three additional animals were also transgenic. These results show that transpositional transgenesis by cytoplasmic injection of SB transposon components can be applied for the production of transgenic lambs of pharmaceutical interest.Instituto de BiotecnologíaFil: Bevacqua, Romina Jimena. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández y Martín, Rafael. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Canel, Natalia Gabriela. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Gibbons, Alejandro Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Texeira, D.I.A. Universidade Estadual do Ceará. Faculdade de Veterinária; BrasilFil: Lange, F. Universidad Maimónides. Laboratorio de Clonación y Transgenesis; ArgentinaFil: Vans Landschoot, Geraldina. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Lange, F. Universidad Maimónides. Laboratorio de Clonación y Transgenesis; ArgentinaFil: Savy, Virginia. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Briski, Olinda. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hiriart, María Inés. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Grueso, Esther. Paul-Ehrlich-Institute; AlemaniaFil: Ivics, Zoltán. Paul-Ehrlich-Institute; AlemaniaFil: Taboga, Oscar Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina.Fil: Kues, Wilfried A. Friedrich-Loeffler-Institut; AlemaniaFil: Ferraris, S.R. Universidad Maimónides. Laboratorio de Clonación y Transgenesis; ArgentinaFil: Salamone, Daniel Felipe. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Paradoxical co-existing base metal sulphides in the mantle: The multi-event record preserved in Loch Roag peridotite xenoliths, North Atlantic Craton

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    The role of the subcontinental lithospheric mantle as a source of precious metals for mafic magmas is contentious and, given the chalcophile (and siderophile) character of metals such as the platinum-group elements (PGE), Se, Te, Re, Cu and Au, the mobility of these metals is intimately linked with that of sulphur. Hence the nature of the host phase(s), and their age and stability in the subcontinental lithospheric mantle may be of critical importance. We investigate the sulphide mineralogy and sulphide in situ trace element compositions in base metal sulphides (BMS) in a suite of spinel lherzolite mantle xenoliths from northwest Scotland (Loch Roag, Isle of Lewis). This area is situated on the margin of the North Atlantic Craton which has been overprinted by a Palaeoproterozoic orogenic belt, and occurs in a region which has undergone magmatic events from the Palaeoproterozoic to the Eocene. We identify two populations of co-existing BMS within a single spinel lherzolite xenolith (LR80) and which can also be recognised in the peridotite xenolith suite as a whole. Both populations consist of a mixture of Fe-Ni-Cu sulphide minerals, and we distinguished between these according to BMS texture, petrographic setting (i.e., location within the xenolith in terms of ‘interstitial’ or within feldspar-spinel symplectites, as demonstrated by X-ray Computed Microtomography) and in situ trace element composition. Group A BMS are coarse, metasomatic, have low concentrations of total PGE (< 40 ppm) and high (Re/Os)N (ranging 1 to 400). Group B BMS strictly occur within symplectites of spinel and feldspar, are finer-grained rounded droplets, with micron-scale PtS (cooperite), high overall total PGE concentrations (15–800 ppm) and low (Re/Os)N ranging 0.04 to 2. Group B BMS sometimes coexist with apatite, and both the Group B BMS and apatite can preserve rounded micron-scale Ca-carbonate inclusions indicative of sulphide-carbonate-phosphate immiscibility. This carbonate-phosphate metasomatic association appears to be important in forming PGE-rich sulphide liquids, although the precise mechanism for this remains obscure. As a consequence of their position within the symplectites, Group B BMS are particularly vulnerable to being incorporated in ascending mantle-derived magmas (either by melting or physical entrainment). Based on the cross-cutting relationships of the symplectites, it is possible to infer the relative ages of each metasomatic BMS population. We tally these with major tectono-magmatic events for the North Atlantic region by making comparisons to carbonatite events recorded in crustal and mantle rocks, and we suggest that the Pt-enrichment was associated with a pre-Carboniferous carbonatite episode. This method of mantle xenolith base metal sulphide documentation may ultimately permit the temporal and spatial mapping of the chalcophile metallogenic budget of the lithospheric mantle, providing a blueprint for assessing regional metallogenic potential. Abbreviations: NAC, North Atlantic Craton; GGF, Great Glen Fault; NAIP, North Atlantic Igneous Province; BPIP, British Palaeogene Igneous Province; SCLM, subcontinental lithospheric mantle; PGE, platinum-group elements; HSE, highly siderophile elements; BMS, base metal sulphid

    The Sudbury Neutrino Observatory

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    The Sudbury Neutrino Observatory is a second generation water Cherenkov detector designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. The detector is unique in its use of D2O as a detection medium, permitting it to make a solar model-independent test of the neutrino oscillation hypothesis by comparison of the charged- and neutral-current interaction rates. In this paper the physical properties, construction, and preliminary operation of the Sudbury Neutrino Observatory are described. Data and predicted operating parameters are provided whenever possible.Comment: 58 pages, 12 figures, submitted to Nucl. Inst. Meth. Uses elsart and epsf style files. For additional information about SNO see http://www.sno.phy.queensu.ca . This version has some new reference

    Carbohydrate metabolism and metabolic disorders in horses Metabolismo de carboidratos e disfunções metabólicas em equinos

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    Horses evolved consuming primarily fermentable forage carbohydrates, but forage diets have been traditionally supplemented with grain meals rich in starch and sugar in order to provide additional calories, protein and micronutrients. Starch and sugar are important for performance horses, but the consumption starch-rich meals may cause equine digestive and metabolic disorders. The critical capacity for preileal starch digestibility appears to be 0.35 to 0.4% but may be as little, depending on the source of starch. Small intestinal absorption of simple sugars is limited by the activity and expression of two classes of glucose carrier proteins, which are affected by chronic intake of hydrolyzable carbohydrate but may be sluggish to respond to abrupt changes in diet, further exacerbating the risk of overload. The most rapid fermentation occurs during starch overload or in the presence of fructans. Rapid fermentation perturbs the microbial and pH balance of the cecum and colon, favoring proliferation of Lactobacillus spp and acid production and increasing the risk of colic and laminitis. In addition to digestive disturbances, feeding grain concentrates rich in hydrolyzable carbohydrate may increase the risk of insulin resistance, which has been associated with obesity, laminitis and chronic founder, developmental orthopedic disease, and Cushing's disease in horses. This threshold concentration of starch intake may be a starting point for horse owners, feed manufacturers and veterinarians that may be claimed to be "low" enough to reduce risk in insulin resistant horses sensitive to grain-associated disorders.<br>Equinos desenvolvem-se consumindo primordialmente os carboidratos fermentáveis das forragens, porém as dietas a base de forragens vem sendo suplementadas com dietas a base de grãos, ricas em amido e açúcar, visando fornecer adicionais calorias, proteínas e micronutrientes. Amido e açucares são importantes para os equinos atletas, porém o consumo de dietas ricas em amido pode causar problemas digestivos e metabólicos aos equinos. A capacidade critica da digestão pré-ileal do amido varia entre 0,35 a 0,4%, podendo ser inferior, dependendo da fonte de amido. A absorção de açucares simples, no intestino delgado, depende da expressão de suas proteínas carreadoras de glicose, as quais são afetadas pela ingestão continua de carboidratos solúveis, porém podem ser mais vagarosas a responder a mudanças abruptas na dieta prevenindo o risco da sobrecarga. A fermentação mais rápida ocorre quando amido não digerido no intestino delgado adentra o intestino grosso e na presença de frutanas. A rápida fermentação perturba o equilíbrio da microbial e do pH de ceco e colon, favorecendo a proliferação de Lactobacillus spp e produção de ácido lático, aumentando o risco de cólicas e laminite. Adicionalmente aos distúrbios digestivos, dietas a base de grãos com alta concentração de carboidratos hidrolisáveis, pode aumentar o risco de resistência a insulina, a qual vem sendo associada com obesidade, laminite, distúrbios crônicos e desenvolvimento de problemas ortopédicos. O valor mínimo de ingestão de amido pode ser um ponto inicial na dieta de cavalos vencedores, processamento de alimentos e veterinários que podem estar recomendado a ser baixo o suficiente para reduzir o risco de resistência e insulina em equinos sensíveis a distúrbios associados a grãos
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