822 resultados para NUTRITION
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Uso de diferentes fuentes de protena en la alimentacin de cerdos en fase de cebo y su relacin con las emisiones de gases amoniaco y metano.
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This study reviews the effects of pig slurry composition on the biochemical methane (CH4) potential (B0), using the information collected in three nutrition assays. A total of 84 animals were used to test the effect of 13 different diets.
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Potassium (K+) nutrition and salt tolerance are key factors controlling plant productivity. However, the mechanisms by which plants regulate K+ nutrition and salt tolerance are poorly understood. We report here the identification of an Arabidopsis thaliana mutant, sos3 (salt-overly-sensitive 3), which is hypersensitive to Na+ and Li+ stresses. The mutation is recessive and is in a nuclear gene that maps to chromosome V. The sos3 mutation also renders the plant unable to grow on low K+. Surprisingly, increased extracellular Ca2+ suppresses the growth defect of sos3 plants on low K+ or 50 mM NaCl. In contrast, high concentrations of external Ca2+ do not rescue the growth of the salt-hypersensitive sos1 mutant on low K+ or 50 mM NaCl. Under NaCl stress, sos3 seedlings accumulated more Na+ and less K+ than the wild type. Increased external Ca2+ improved K+/Na+ selectivity of both sos3 and wild-type plants. However, this Ca2+ effect in sos3 is more than twice as much as that in the wild type. In addition to defining the first plant mutant with an altered calcium response, these results demonstrate that the SOS3 locus is essential for K+ nutrition, K+/Na+ selectivity, and salt tolerance in higher plants.
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ATP, which is present in the extracellular matrix of multicellular organisms and in the extracellular fluid of unicellular organisms, has been shown to function as a signaling molecule in animals. The concentration of extracellular ATP (xATP) is known to be functionally modulated in part by ectoapyrases, membrane-associated proteins that cleave the - and -phosphates on xATP. We present data showing a previously unreported (to our knowledge) linkage between apyrase and phosphate transport. An apyrase from pea (Pisum sativum) complements a yeast (Saccharomyces cerevisiae) phosphate-transport mutant and significantly increases the amount of phosphate taken up by transgenic plants overexpressing the gene. The transgenic plants show enhanced growth and augmented phosphate transport when the additional phosphate is supplied as inorganic phosphate or as ATP. When scavenging phosphate from xATP, apyrase mobilizes the -phosphate without promoting the transport of the purine or the ribose.
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While the last 50 years of agriculture have focused on meeting the food, feed, and fiber needs of humans, the challenges for the next 50 years go far beyond simply addressing the needs of an ever-growing global population. In addition to producing more food, agriculture will have to deal with declining resources like water and arable land, need to enhance nutrient density of crops, and achieve these and other goals in a way that does not degrade the environment. Biotechnology and other emerging life sciences technologies offer valuable tools to help meet these multidimensional challenges. This paper explores the possibilities afforded through biotechnology in providing improved agronomic input traits, differentiated crops that impart more desirable output traits, and using plants as green factories to fortify foods with valuable nutrients naturally rather than externally during food processing. The concept of leveraging agriculture as green factories is expected to have tremendous positive implications for harnessing solar energy to meet fiber and fuel needs as well. Widespread adaptation of biotech-derived products of agriculture should lay the foundation for transformation of our society from a production-driven system to a quality and utility-enhanced system.
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Acclimation of photosynthesis to elevated CO2 has previously been shown to be more pronounced when N supply is poor. Is this a direct effect of N or an indirect effect of N by limiting the development of sinks for photoassimilate? This question was tested by growing a perennial ryegrass (Lolium perenne) in the field under elevated (60 Pa) and current (36 Pa) partial pressures of CO2 (pCO2) at low and high levels of N fertilization. Cutting of this herbage crop at 4- to 8-week intervals removed about 80% of the canopy, therefore decreasing the ratio of photosynthetic area to sinks for photoassimilate. Leaf photosynthesis, in vivo carboxylation capacity, carbohydrate, N, ribulose-1,5-bisphosphate carboxylase/oxygenase, sedoheptulose-1,7-bisphosphatase, and chloroplastic fructose-1,6-bisphosphatase levels were determined for mature lamina during two consecutive summers. Just before the cut, when the canopy was relatively large, growth at elevated pCO2 and low N resulted in significant decreases in carboxylation capacity and the amount of ribulose-1,5-bisphosphate carboxylase/oxygenase protein. In high N there were no significant decreases in carboxylation capacity or proteins, but chloroplastic fructose-1,6-bisphosphatase protein levels increased significantly. Elevated pCO2 resulted in a marked and significant increase in leaf carbohydrate content at low N, but had no effect at high N. This acclimation at low N was absent after the harvest, when the canopy size was small. These results suggest that acclimation under low N is caused by limitation of sink development rather than being a direct effect of N supply on photosynthesis.
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Within the context of the health reforms introduced in Spain in the early 20th century and the influence of international health organisations on their development, this article analyses the growing interest that surrounded nourishment and food-related problems at that time in relation to healthcare, the diagnosis provided by hygienists of such problems, and the public health measures applied to resolve them. The issue of hygienic diet and the collective aspect of nutritional problems became priorities in the field of healthcare. Two of the most prominent initiatives involved setting up a Department of Nutrition and Food Hygiene and Bromatological Technique during the early years of the Second Republic, as part of the National School of Health, as well as a Food Hygiene Service. Spanish hygienists underlined the importance of education and the dissemination of information about food hygiene, health and nutrition, in order to overcome the qualitative and quantitative deficiencies observed in the average diet of the Spanish population.
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The objective of this work was to study the effect of root and foliar application of two commercial products containing amino acids from plant and animal origin on iron (Fe) nutrition of tomato seedlings cultivated in two nutrient media: lime and normal nutrient solutions. In the foliar-application experiment, each product was sprayed with 0.5 and 0.7mL L1 2, 7, 12, and 17 d after transplanting. In the root application experiment, 0.1 and 0.2mL L1 of amino acids products were added to the nutrient solutions. In both experiments, untreated control plants were included as well. Foliar and root application of the product containing amino acids from animal origin caused severe plant-growth depression and nonpositive effects on Fe nutrition were found. In contrast, the application of the product from plant origin stimulated plant growth. Furthermore, significantly enhanced root and leaf FeIII-chelate reductase activity, chlorophyll concentration, leaf Fe concentration, and FeII : Fe ratio were found in tomato seedlings treated with the product from plant origin, especially when the amino acids were directly applied to the roots. These effects were more evident in plants developed under lime-induced Fe deficiency. The positive results on Fe uptake may be related to the action of glutamic acid, the most abundant amino acid in the formulation of the product from plant origin.
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La dysplasie broncho-pulmonaire (DBP), caractrise par un dfaut de lalvolarisation, est une complication pathologique associe un stress oxydant chez le nouveau-n prmatur. La DBP est prsente chez prs de 50 % des nouveau-ns de moins de 29 semaines de gestation. La nutrition parentrale (NP) que ces nouveau-ns reoivent pour cause dimmaturit gastro-intestinale est une source importante de stress oxydant. En effet, leur NP est contamine par des peroxydes, dont lascorbylperoxyde qui est une forme peroxyde du dshydroascorbate. La gnration des peroxydes est catalyse par la lumire ambiante. La photoprotection de la NP, quoique difficile dapplication en clinique, est associe une diminution de lincidence de la DBP chez les enfants prmaturs. Chez lanimal nouveau-n, la photoprotection de la NP est associe un meilleur dveloppement alvolaire. Ainsi, nous mettons lhypothse que lascorbylperoxide infus avec la NP cause la perte dalvoles suite une apoptose exagre induite par loxydation du potentiel redox du glutathion. Cette oxydation du potentiel redox serait occasionne par linhibition de la transformation hpatique de la mthionine en cystine, menant une diminution de la synthse de glutathion au foie et dans les tissus tels que les poumons. La confirmation de cette hypothse suggrera quun ajout de glutathion dans la NP permettra une meilleure dtoxification de lascorbylperoxide par laction de la glutathion peroxydase, et prviendra loxydation du potentiel redox et ainsi, la perte d'alvoles par apoptose. Objectifs : Le but de mon projet de recherche est de comprendre les mcanismes biochimiques liant la NP et le dveloppement de la DBP chez le nouveau-n prmatur et de proposer une alternative nutritionnelle prvenant le dveloppement de cette complication frquemment observe dans cette population. Les objectifs spcifiques sont : 1) dvaluer limpact, au poumon, de linfusion de lascorbylperoxyde sur laxe mtabolique potentiel redox du glutathion - apoptose - le dveloppement alvolaire; 2) dtudier limpact de lascorbylperoxyde et du potentiel redox sur lactivit hpatique de la mthionine adnosyltransfrase (MAT), premire enzyme de la cascade mtabolique transformant la mthionine en cystine; et 3) de tenter de prvenir limpact ngatif de la NP ou de linfusion dascorbylperoxyde sur le poumon en amliorant le statut en glutathion. Mthodes: Par un cathter fix dans la jugulaire, des cochons dInde de trois jours de vie (n = 8 par groupe) ont reu en continu durant 4 jours une NP ou une solution de base (dextrose + NaCl) enrichie des diffrentes molcules lessai. Le premier objectif a t atteint en enrichissant la solution de base en ascorbylperoxyde 0, 20, 60 et 180 M. Ces solutions contenaient ou non 350 M H2O2 pour se rapprocher des conditions cliniques. Le second objectif a t atteint en investiguant les mcanismes dinhibition de la MAT dans des animaux infuss ou non avec des solutions contenant la solution de base, des peroxydes, du glutathion et la NP (dextrose + acides amins + multivitamines + lipides). Le troisime objectif a t atteint en ajoutant ou non une solution dascorbylperoxide ou la NP 10 M de glutathion (GSSG), afin dobtenir une concentration plasmatique normale de glutathion. Aprs 4 jours, les poumons taient prlevs et traits pour la dtermination de GSH et GSSG par lectrophorse capillaire, le potentiel redox tait calcul selon l'quation de Nernst et le niveau de caspase-3 actif (marqueur dapoptose) par Western blot et lindex dalvolarisation quantifi par le nombre dinterceptes entre des structures histologiques et une droite calibre. Les donnes taient compares par ANOVA, les effets taient considrs comme significatifs si le p tait infrieur 0,05. Rsultats: Linfusion de lascorbylperoxyde, indpendamment du H2O2, a induit une hypoalvolarisation, une activation de la caspase-3 et une oxydation du potentiel redox de manire dose-dpendante. Ces effets ont t empchs par lajout de GSSG la NP ou la solution dascorbylperoxyde (180 M). Lascorbylperoxyde et le H2O2 ont inhib lactivit de MAT tandis quelle tait linairement module par la valeur du potentiel redox hpatique. Conclusion : Nos rsultats suggrent que lascorbylperoxyde est lagent actif de la NP conduisant au dveloppement de la DBP. Ainsi la correction des bas niveaux de glutathion induits par les peroxydes de la NP favorise la dtoxification des peroxydes et la correction du potentiel redox pulmonaire ; ce qui a protg les poumons des effets dltres de la NP en outrepassant linhibition de la MAT hpatique. Nos rsultats sont d'une grande importance car ils donnent de l'espoir pour une prvention possible de la DBP.
