196 research outputs found

    Spatial uncertainty in sap velocity measurements and tree water use upscaling in american beech

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    4 páginas.-- 3 figuras.-- 10 referencias.-- Póster presentado en el XI Simposio Hispano-Portugués de Relaciones Hídricas en las Plantas, Sevilla 17-20 Sep. (2012)We examined the variation insap velocity radially, azimuthally, at different heights and across different tree sizes for the species Fagus grandifolia. The results demonstrate that the main sources of variability are radial variability and tree size. The implications for scaling up routine point measurements of sap velocity to the whole-tree andstand levels are discussed.This work was funded by the University of New Hampshire. We thank the US Forest Service at BEF and Hubbard Brook for the facilitation of research activities and permission to access sites.N

    Linking changes in radial profiles of sap flux density with the response of water vapour exchange to water deficit

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    8 páginas, 5 figuras, 1 tabla, 19 referencias.-- IX International Workshop on Sap Flow, celebrado del 4-7 de junio 2013, en Gante, Bélgica.Knowledge of temporal variations in radial profiles of sap flux density (Js) and its relation to canopy water vapour exchange would help to improve our understanding of plant water relations. In this study we aimed to test if there is a consistent radial profile of Js in olive trees under optimal soil water availability and severe water stress conditions. Furthermore, if the radial profile of Js is not consistent through time we aimed to assess whether this radial variability can be explained through differential water exchange response to evaporative demand (D) of sun-exposed, new foliage and shade, old foliage. We measured sap flux density in the trunk of 6-year-old olive trees under two different irrigation treatments: a full irrigation treatment and a treatment replacing 30% of the of irrigation needs. We related the hourly radial profiles characterized with the Beta probability distribution function with independent water vapour exchange measurements at different exposures in the tree canopy (sun-exposed, young foliage and shade, old foliage). Results showed that under well irrigated conditions the shape of the radial profile of Js hardly varied, but under water deficit situations most of the sap appears to be conducted deeper into the sapwood and Js is also more variable throughout the sapwood. Accordingly, results demonstrated that in shade, old foliage water vapour exchange varied less than in sun-exposed new foliage. As a result, in days under severe water deficit, the contribution of shade old foliage to the whole tree transpiration was greater. Radial profile changes and canopy measurements were found to respond in a similar way to D. During conditions of low D and soil water deficit it was observed a greater contribution of the inner xylem to total stem flow and shade, old leaves to canopy gas exchange.Peer reviewe

    Digestible lysine effects on gene expression by Japanese quails in the pre-laying phase

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    This study aimed to determine the effects of digestible lysine levels in the diets of Japanese quail (Coturnix coturnix japonica) on performance, blood parameters and the expression of insulin-like growth factor I, and growth hormone receptor (GHR), apolipoprotein A-I (APOA-I), acetyl-CoA-carboxylase (ACC), and fatty acid synthase (FAS) genes. A total of 288 seven-day-old female Japanese quails were randomly assigned to one of three diets that contained 0.8%, 1.10%, or 1.40% digestible lysine. The birds were slaughtered at 42 days old, and relative gene expression was evaluated in the liver by qRT-PCR using the 2-ΔCT method. Lysine supplementation had no effect on weight gain and feed conversion. Abdominal fat was lower in birds supplemented with 0.8% digestible lysine than those supplemented with 1.10% and 1.40%. Increased total cholesterol and triglycerides were elevated in quails that received supplementation of 1.10% digestible lysine compared with the other diets. High density lipoproteins were decreased in birds that received 0.8% digestible lysine. Quails fed with 1.40% digestible lysine had greater expression of GHR and APOA-I than quails fed diets with 0.8 and 1.10% (P <0.05). The greatest expressions of ACC and FAS were observed in the liver of quails fed with 0.8% digestible lysine. The current results suggest that lysine supplementation in the pre-laying phase allows birds to deposit muscle mass to reach the optimal conformation and body fatness that provides an energetic reserve for the productive phase by modulating the expression of genes related to growth and lipid metabolism. Keywords: Coturnix coturnix japonica, growth, growth hormone, lipid synthesis, lipid metabolis

    A novel human pain insensitivity disorder caused by a point mutation in ZFHX2

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    Chronic pain is a major global public health issue causing a severe impact on both the quality of life for sufferers and the wider economy. Despite the significant clinical burden, little progress has been made in terms of therapeutic development. A unique approach to identifying new human-validated analgesic drug targets is to study rare families with inherited pain insensitivity. Here we have analysed an otherwise normal family where six affected individuals display a pain insensitive phenotype that is characterized by hyposensitivity to noxious heat and painless bone fractures. This autosomal dominant disorder is found in three generations and is not associated with a peripheral neuropathy. A novel point mutation in ZFHX2, encoding a putative transcription factor expressed in small diameter sensory neurons, was identified by whole exome sequencing that segregates with the pain insensitivity. The mutation is predicted to change an evolutionarily highly conserved arginine residue 1913 to a lysine within a homeodomain. Bacterial artificial chromosome (BAC) transgenic mice bearing the orthologous murine p.R1907K mutation, as well as Zfhx2 null mutant mice, have significant deficits in pain sensitivity. Gene expression analyses in dorsal root ganglia from mutant and wild-Type mice show altered expression of genes implicated in peripheral pain mechanisms. The ZFHX2 variant and downstream regulated genes associated with a human pain-insensitive phenotype are therefore potential novel targets for the development of new analgesic drugs. awx326media1 5680039660001 The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.We thank the Medical Research Council (J.J.C., Career Development Award, G1100340), Wellcome Trust (200183/ Z/15/Z and 101054/Z/13/Z) and Arthritis Research UK (20200) for generous support and Shionogi for an academic research grant (165302). Thanks to the University of Siena for partially funding this research. J.T.B. is supported by a Research Fellowship from the Alzheimer�s Society. J.D.R. received funding from the Wellcome Trust through the London Pain Consortium and from Colciencias through a Francisco Jose de Caldas Scholarship (LASPAU, Harvard University). D.L.H.B. is a Wellcome senior clinical scientist (ref. no. 095698z/11/z and 202747/Z/16/Z) and member of the Wellcome Pain Consortium.Scopu
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