Spatially explicit correlates of plant functional traits inform landscape patterns of resource quality     

Heckford  Travis R.  Leroux  Shawn J.  Vander Wal  Eric  Rizzuto  Matteo  Balluffi-Fry  Juliana  Richmond  Isabella C.  Wiersma  Yolanda F. 《Landscape Ecology》2022,37(1):59-80

Landscape Ecology - Spatially explicit correlates of foliar elemental, stoichiometric, and phytochemical (ESP) traits represent links to landscape patterns of resource quality. We investigate...  相似文献   

Levels of bisphenol A in canned liquid infant formula products in Canada and dietary intake estimates     

Cao XL  Dufresne G  Belisle S  Clement G  Falicki M  Beraldin F  Rulibikiye A 《Journal of agricultural and food chemistry》2008,56(17):7919-7924

A sensitive, efficient, and reproducible method, based on solid phase extraction and derivatization with acetic anhydride followed by gas chromatography-mass spectrometry in selected-ion monitoring mode, was developed for the determination of bisphenol A (BPA) in liquid infant formula. The method quantification limit was 0.5 ng g(-1). Extraction recoveries were 85-94% over the concentration range of 2.5-20 ng g(-1). Good reproducibility of the method was observed at levels of 0.54 and 10.4 ng g(-1) with relative standard deviations of 5.0 and 2.8%, respectively. The method was used to analyze samples of 21 canned liquid infant formula products for BPA. BPA was detected in all samples at levels ranging from as low as 2.27 ng g(-1) to as high as 10.2 ng g(-1). The probable daily intakes of BPA due to consumption of canned liquid infant formula were estimated for infants from premature to 12-18 months of age. The maximum probable daily intake of BPA was 1.35 microg kg(-1) of body weight day(-1) for 0-1-month-old infants with the maximum formula intake, which is below the provisional tolerable daily intake for BPA established by Health Canada, 25 microg kg(-1) of body weight day(-1).  相似文献   

Medicine. Mouse study suggests cancer drugs could help prematurely aging kids     

Travis J 《Science (New York, N.Y.)》2006,311(5763):934-935

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A comparative analysis of simulated and observed photosynthetic CO2 uptake in two coniferous forest canopies     

Ibrom A  Jarvis PG  Clement R  Morgenstern K  Oltchev A  Medlyn BE  Wang YP  Wingate L  Moncrieff JB  Gravenhorst G 《Tree physiology》2006,26(7):845-864

Gross canopy photosynthesis (P(g)) can be simulated with canopy models or retrieved from turbulent carbon dioxide (CO2) flux measurements above the forest canopy. We compare the two estimates and illustrate our findings with two case studies. We used the three-dimensional canopy model MAESTRA to simulate P(g) of two spruce forests differing in age and structure. Model parameter acquisition and model sensitivity to selected model parameters are described, and modeled results are compared with independent flux estimates. Despite higher photon fluxes at the site, an older German Norway spruce (Picea abies L. (Karst.)) canopy took up 25% less CO2 from the atmosphere than a young Scottish Sitka spruce (Picea sitchensis (Bong.) Carr.) plantation. The average magnitudes of P(g) and the differences between the two canopies were satisfactorily represented by the model. The main reasons for the different uptake rates were a slightly smaller quantum yield and lower absorptance of the Norway spruce stand because of a more clumped canopy structure. The model did not represent the scatter in the turbulent CO2 flux densities, which was of the same order of magnitude as the non-photosynthetically-active-radiation-induced biophysical variability in the simulated P(g). Analysis of residuals identified only small systematic differences between the modeled flux estimates and turbulent flux measurements at high vapor pressure saturation deficits. The merits and limitations of comparative analysis for quality evaluation of both methods are discussed. From this analysis, we recommend use of both parameter sets and model structure as a basis for future applications and model development.  相似文献   

Soluble Mn(III) in suboxic zones     

Trouwborst RE  Clement BG  Tebo BM  Glazer BT  Luther GW 《Science (New York, N.Y.)》2006,313(5795):1955-1957

Soluble manganese(III) [Mn(III)] has been thought to disproportionate to soluble Mn(II) and particulate Mn(IV)O2 in natural waters, although it persists as complexes in laboratory solutions. We report that, in the Black Sea, soluble Mn(III) concentrations were as high as 5 micromolar and constituted up to 100% of the total dissolved Mn pool. Depth profiles indicated that soluble Mn(III) was produced at the top of the suboxic zone by Mn(II) oxidation and at the bottom of the suboxic zone by Mn(IV)O2 reduction, then stabilized in each case by unknown natural ligands. We also found micromolar concentrations of dissolved Mn(III) in the Chesapeake Bay. Dissolved Mn(III) can maintain the existence of suboxic zones because it can act as either an electron acceptor or donor. Our data indicate that Mn(III) should be ubiquitous at all water column and sediment oxic/anoxic interfaces in the environment.  相似文献   

Exploring ethyl methanesulfonate (EMS) treated cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) to improve drought tolerance     

Travis W. Witt  Mauricio Ulloa  Mathew G. Pelletier  Venugopal Mendu  Glen L. Ritchie 《Euphytica》2018,214(7):123

The Texas High Plains often has extended periods between rainfall events, which can lead to a reduction in the yield and fiber quality of cotton (Gossypium hirsutum L.). It is known that cultivated cotton suffers from low levels of genetic diversity due to the over-use in breeding of similar gene pools, which may hinder breeding for drought tolerance. In this study, for the first time the novel variability or genetic diversity of morphological and agronomic traits possibly created by the chemical mutagen ethyl methanesulfonate (EMS) was evaluated to improve drought tolerance in cotton by traits’ response to different irrigation regimes. EMS is a chemical mutagen that has been shown to cause point mutations in the DNA of many model plants and crop species. Three EMS treated lines were advanced from the M₁ to M₄ generation as bulk-harvested populations. A diverse selection scheme was applied to capture most of the genetic trait-variability or diversity and superior lines in these populations. In 2014–2016 the diversity of these populations was evaluated based on four agronomic and thirteen morphological traits to determine differences in response to multiple irrigation rates. Analyses of these traits showed statistically significant (p?≤?0.05) differences between and within populations when compared to the original non-treated EMS source, with most of the variability being observed in the high irrigation rate. However, none of the EMS treated populations had significantly (p?≤?0.05) better lint yield than the commercial cultivar (control) in 2016. EMS yield performance was possibly constrained by the applied diverse selection scheme of this study. Traits such as total number of bolls, bolls retained at node 7 and below, and those retained between nodes 8 and 12, and bolls retained at node of first fruiting branch may be predictors to improve cotton production (yield) in water limiting environments.  相似文献   

Cloning and large-scale expansion of epitope-specific equine cytotoxic T lymphocytes using an anti-equine CD3 monoclonal antibody and human recombinant IL-2     

Mealey RH  Littke MH  Leib SR  Davis WC  McGuire TC 《Veterinary immunology and immunopathology》2007,118(1-2):121-128

Cytotoxic T lymphocytes are involved in controlling intracellular pathogens in many species, including horses. Particularly, CTL are critical for the control of equine infectious anemia virus (EIAV), a lentivirus that infects horses world-wide. In humans and animal models, CTL clones are valuable for evaluating the fine specificity of epitope recognition, and for adoptive immunotherapy against infectious and neoplastic diseases. Cloned CTL would be equally useful for similar studies in the horse. Here we present the first analysis of a method to generate equine CTL clones. Peripheral blood mononuclear cells were obtained from an EIAV-infected horse and stimulated with the EIAV Rev-QW11 peptide. Sorted CD8+ T cells were cloned by limiting dilution, and expanded without further antigen addition using irradiated PBMC, anti-equine CD3, and human recombinant IL-2. Clones could be frozen and thawed without detrimental effects, and could be subsequently expanded to numbers exceeding 2 x 10(9)cells. Flow cytometry of expanded clones confirmed the CD3+/CD8+ phenotype, and chromium release assays confirmed CTL activity. Finally, sequencing TCR beta chain genes confirmed clonality. Our results provide a reliable means to generate large numbers of epitope-specific equine CTL clones that are suitable for use in downstream applications, including functional assays and adoptive transfer studies.  相似文献   

Nitrogen requirements for deficit-irrigated bermudagrass (Cynodon spp.) fairways in South Florida     

Marco Schiavon  Travis W. Shaddox  Karen E. Williams  Sergio Gallo  P. Agustin Boeri  J. Bryan Unruh  Jason Kruse  Kevin Kenworthy 《Journal of Agronomy and Crop Science》2023,209(1):1-11

Several new bermudagrass cultivars are available and commonly used on golf course fairways. However, little is known about their cultural requirements or how these cultivars perform under lower inputs regimes. A 2-year study was conducted at University of Florida, Fort Lauderdale Research and Education Center, to assess performance of four hybrid bermudagrass [Cynodon dactylon L. Pers. X Cynodon transvaalensis (Burtt-Davy)] cultivars (‘Latitude 36’, ‘Tifway 419’, ‘TifGrand’ and ‘TifTuf’), and 2 common bermudagrass (Cynodon dactylon L. Pers.) cultivars (‘Bimini’ and ‘Celebration’) irrigated at either 50% or 80% reference evapotranspiration (ET_o) and fertilised at either 0, 146, 244, or 342 kg N ha⁻¹ year⁻¹. Plots were evaluated monthly for turfgrass quality, dark green colour index (DGCI), normalised difference vegetation index (NDVI), and Chlorophyll Index, and seasonally for N tissue content. Plots watered at 80% ET_o enhanced bermudagrass quality compared to 50% ET_o, DGCI and NDVI only in two months out of 24. Latitude 36 and Celebration were the top-rated cultivars, and their quality was not affected by no N fertilisation. Conversely, TifGrand, TifTuf and Tifway that received no N fertilisation resulted in insufficient quality during the second year of the study. Insufficient quality may be linked to reduced N metabolization compared to the highest rated cultivars. Results show that new cultivars such as Latitude 36 and Bimini could be maintained at sufficient quality levels with reduced water and N inputs in South Florida.  相似文献