Determining the potential to breed for enhanced antioxidant status in Malus: mean inter- and intravarietal fruit vitamin C and glutathione contents at harvest and their evolution during storage     

Davey MW  Keulemans J 《Journal of agricultural and food chemistry》2004,52(26):8031-8038

Vitamin C (L-ascorbate, L-ascorbic acid; L-AA) and glutathione (GSH) are major hydrophilic antioxidants in plants with important roles in stress resistance and nutrition. To evaluate the potential for breeding for enhanced levels of these compounds, a comprehensive screen of the fruit from some 31 apple (Malus) cultivars has been carried out to determine the biodiversity present in the mean inter- and intracultivar concentrations of both the oxidized and reduced forms of these compounds, as well as the impact of storage on their concentrations. It is noted that despite limited variation at harvest, cultivars differed substantially in their ability to maintain L-AA levels during storage, primarily due to the loss of L-AA by "low-vitamin C" cultivars. Generally, cultivars that could maintain their L-AA and GSH pools also had better storage properties. Interestingly, there was also a correlation between fruit vitamin C contents and the harvest date, such that cultivars with the highest vitamin C contents were harvested latest in the season and the lowest contents were found among the early varieties. Correlations with other physiological parameters, however, were too weak to serve as useful predictive tools.  相似文献   

Variability in Mapping Acidification Risk Scenarios for Terrestrial Ecosystems in Asian Countries     

Johan C.I. Kuylenstierna  W. Kevin Hicks  Steve Cinderby  Harry W. Vallack  Magnuz Engardt 《Water, air, and soil pollution》2001,130(1-4):1175-1180

Acidification has the potential to become a widespread problem in parts of Asia. Just how widespread this risk may be is discussed by comparing sulphur deposition to critical load estimates, taking into account neutralising base cation deposition from soil dust. Two scenarios for the sulphur emission in 2025 are used as inputs to the MATCH atmospheric transfer model to estimate sulphur deposition scenarios. Net acidic deposition using a low and high base cation deposition input is compared to a map of sensitivity of terrestrial ecosystems to acidic deposition. Two ranges of critical loads assigned to this sensitivity map are used. The variability in the maps showing risks of acidification using low and high estimates for critical loads and base cation deposition for two different development pathways is discussed. Certain areas are shown to be at risk in all cases whereas others are very sensitive to the values used to estimate risk.  相似文献   

Reference values for serum levels of vitamin B12 and folic acid in a population-based sample of adults between 35 and 80 years of age     

Wahlin A  Bäckman L  Hultdin J  Adolfsson R  Nilsson LG 《Public health nutrition》2002,5(3):505-511

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Development of the Regional Policy Process for Air Pollution in South Asia,Southern Africa and Latin America     

Hicks  W. Kevin  Kuylenstierna  Johan C.I.  Mathur  Vikrom  Mazzucchelli  Sergio  Burijson  Viviana  Shrestha  Surendra  Iyngararasan  Mylvakanam  Simukanga  Stephen  Van Tienhoven  A. Mieke 《Water, air, and soil pollution》2001,130(1-4):211-216

Projections indicate that large increases in emissions may occur in developing countries during the next twenty to fifty years if current development patterns persist. This paper describes the development of co-operation regarding air pollution issues in three sub-regions of three continents. Experiences gained through activities within a programme on Regional Air Pollution in Developing Countries are used to illustrate progress. The sub-regional process in South Asia developed through a series of meetings that led to the Malé Declaration. In southern Africa a policy dialogue led to the Harare Resolution targeted towards progress in the SADC region. A policy dialogue in Buenos Aires concentrated on issues related to regional harmonisation of legal frameworks in the Mercosur region. In all regions the link between scientific information required to support decision making has been emphasised. The sub-regional policy processes are analysed in relation to availability of required scientific information and compared to the process that led to protocol development in Europe.  相似文献   

Assessment of shoreline vegetation in relation to use by molting black brant Branta bernicla nigricans on the Alaska coastal plain     

Milton W. Weller  K.C. Jensen  Eric J. Taylor  Mark W. Miller  Karen S. Bollinger  Dirk V. Derksen  Daniel Esler  Carl Markon 《Biological conservation》1994,70(3):219-225

To evaluate the importance of large thaw lakes on the Alaska Coastal Plain for molting Pacific black brant Branta bernicla nigricans, distribution and life form of shoreline vegetation were assessed using several scales: satellite imagery, point-intercept transects, cover quadrats, and a parameter for water regime. Brant population and distribution estimates from aerial surveys were used to classify large lakes into high, moderate, and low use. Correlations between brant and abundance of their preferred feeding site — moss flats — were best demostrated by satellite imagery. Intercepts and cover ratings were not correlated, presumably because these techniques were less efficient at assessing area. General observations suggested that the presence of islands, large ice floes, and possibly other physical attributes of the habitat, influenced brant distribution. This area is unique because of low-lying, drained-lake basins that have ideal combinations of moss flats and large water areas where brant seek protection disturbance is vital to the success of this declining species because alternate habitats may not be available elsewhere on the Coastal Plain. in water or on ice floes. Protection of the area from  相似文献   

Retraction     

Tomkins JL  Penrose MA  Greeff J  Lebas NR 《Science (New York, N.Y.)》2011,333(6047):1220

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Modulation of ATP-dependent chromatin-remodeling complexes by inositol polyphosphates     

Shen X  Xiao H  Ranallo R  Wu WH  Wu C 《Science (New York, N.Y.)》2003,299(5603):112-114

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Phonon dispersions of fcc delta-plutonium-gallium by inelastic x-ray scattering     

Wong J  Krisch M  Farber DL  Occelli F  Schwartz AJ  Chiang TC  Wall M  Boro C  Xu R 《Science (New York, N.Y.)》2003,301(5636):1078-1080

We report an experimental determination of the phonon dispersion curves in a face-centered cubic (fcc) delta-plutonium-0.6 weight % gallium alloy. Several unusual features, including a large elastic anisotropy, a small-shear elastic modulus C', a Kohn-like anomaly in the T1[011] branch, and a pronounced softening of the [111] transverse modes, are found. These features can be related to the phase transitions of plutonium and to strong coupling between the lattice structure and the 5f valence instabilities. Our results also provide a critical test for theoretical treatments of highly correlated 5f electron systems as exemplified by recent dynamical mean field theory calculations for delta-plutonium.  相似文献   

Beyond the ivory tower. A distant mirror for the brain     

Zimmer C 《Science (New York, N.Y.)》2004,303(5654):43-44

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Sirt5 is a NAD-dependent protein lysine demalonylase and desuccinylase   总被引：1，自引：0，他引：1  

Du J  Zhou Y  Su X  Yu JJ  Khan S  Jiang H  Kim J  Woo J  Kim JH  Choi BH  He B  Chen W  Zhang S  Cerione RA  Auwerx J  Hao Q  Lin H 《Science (New York, N.Y.)》2011,334(6057):806-809

Silent information regulator 2 (Sir2) proteins (sirtuins) are nicotinamide adenine dinucleotide-dependent deacetylases that regulate important biological processes. Mammals have seven sirtuins, Sirt1 to Sirt7. Four of them (Sirt4 to Sirt7) have no detectable or very weak deacetylase activity. We found that Sirt5 is an efficient protein lysine desuccinylase and demalonylase in vitro. The preference for succinyl and malonyl groups was explained by the presence of an arginine residue (Arg(105)) and tyrosine residue (Tyr(102)) in the acyl pocket of Sirt5. Several mammalian proteins were identified with mass spectrometry to have succinyl or malonyl lysine modifications. Deletion of Sirt5 in mice appeared to increase the level of succinylation on carbamoyl phosphate synthase 1, which is a known target of Sirt5. Thus, protein lysine succinylation may represent a posttranslational modification that can be reversed by Sirt5 in vivo.  相似文献