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961.
Regional grassland productivity responses to precipitation during multiyear above‐ and below‐average rainfall periods 下载免费PDF全文
Matthew D. Petrie Debra P. C. Peters Jin Yao John M. Blair Nathan D. Burruss Scott L. Collins Justin D. Derner Laureano A. Gherardi John R. Hendrickson Osvaldo E. Sala Patrick J. Starks Jean L. Steiner 《Global Change Biology》2018,24(5):1935-1951
There is considerable uncertainty in the magnitude and direction of changes in precipitation associated with climate change, and ecosystem responses are also uncertain. Multiyear periods of above‐ and below‐average rainfall may foretell consequences of changes in rainfall regime. We compiled long‐term aboveground net primary productivity (ANPP) and precipitation (PPT) data for eight North American grasslands, and quantified relationships between ANPP and PPT at each site, and in 1–3 year periods of above‐ and below‐average rainfall for mesic, semiarid cool, and semiarid warm grassland types. Our objective was to improve understanding of ANPP dynamics associated with changing climatic conditions by contrasting PPT–ANPP relationships in above‐ and below‐average PPT years to those that occurred during sequences of multiple above‐ and below‐average years. We found differences in PPT–ANPP relationships in above‐ and below‐average years compared to long‐term site averages, and variation in ANPP not explained by PPT totals that likely are attributed to legacy effects. The correlation between ANPP and current‐ and prior‐year conditions changed from year to year throughout multiyear periods, with some legacy effects declining, and new responses emerging. Thus, ANPP in a given year was influenced by sequences of conditions that varied across grassland types and climates. Most importantly, the influence of prior‐year ANPP often increased with the length of multiyear periods, whereas the influence of the amount of current‐year PPT declined. Although the mechanisms by which a directional change in the frequency of above‐ and below‐average years imposes a persistent change in grassland ANPP require further investigation, our results emphasize the importance of legacy effects on productivity for sequences of above‐ vs. below‐average years, and illustrate the utility of long‐term data to examine these patterns. 相似文献
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965.
Genomewide association study for susceptibility genes contributing to familial Parkinson disease 总被引:1,自引:0,他引:1
Pankratz N Wilk JB Latourelle JC DeStefano AL Halter C Pugh EW Doheny KF Gusella JF Nichols WC Foroud T Myers RH;PSG-PROGENI GenePD Investigators Coordinators Molecular Genetic Laboratories 《Human genetics》2009,124(6):593-605
Five genes have been identified that contribute to Mendelian forms of Parkinson disease (PD); however, mutations have been
found in fewer than 5% of patients, suggesting that additional genes contribute to disease risk. Unlike previous studies that
focused primarily on sporadic PD, we have performed the first genomewide association study (GWAS) in familial PD. Genotyping
was performed with the Illumina HumanCNV370Duo array in 857 familial PD cases and 867 controls. A logistic model was employed
to test for association under additive and recessive modes of inheritance after adjusting for gender and age. No result met
genomewide significance based on a conservative Bonferroni correction. The strongest association result was with SNPs in the
GAK/DGKQ region on chromosome 4 (additive model: p = 3.4 × 10−6; OR = 1.69). Consistent evidence of association was also observed to the chromosomal regions containing SNCA (additive model: p = 5.5 × 10−5; OR = 1.35) and MAPT (recessive model: p = 2.0 × 10−5; OR = 0.56). Both of these genes have been implicated previously in PD susceptibility; however, neither was identified in
previous GWAS studies of PD. Meta-analysis was performed using data from a previous case–control GWAS, and yielded improved
p values for several regions, including GAK/DGKQ (additive model: p = 2.5 × 10−7) and the MAPT region (recessive model: p = 9.8 × 10−6; additive model: p = 4.8 × 10−5). These data suggest the identification of new susceptibility alleles for PD in the GAK/DGKQ region, and also provide further support for the role of SNCA and MAPT in PD susceptibility.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
N. Pankratz and J. B. Wilk are joint first authors. 相似文献
966.
Kendal S. Broadie Michael Bate Nathan J. Tublitz 《Development genes and evolution》1991,199(6):327-334
Summary A complete timetable of embryonic development of the tobacco hawkmoth,Manduca sexta (Lepidoptera: Sphingidae), is presented. Using living embryos, 20 developmental stages from oviposition to hatching are described with respect to their morphological and physiological maturation. This staging series provides a simple method to identify the stage ofManduca development during all phases of embryogenesis. 相似文献
967.
Peter A. Moran John Hunt Christopher Mitchell Michael G. Ritchie Nathan W. Bailey 《Journal of evolutionary biology》2020,33(7):990-1005
A major challenge for studying the role of sexual selection in divergence and speciation is understanding the relative influence of different sexually selected signals on those processes in both intra‐ and interspecific contexts. Different signals may be more or less susceptible to co‐option for species identification depending on the balance of sexual and ecological selection acting upon them. To examine this, we tested three predictions to explain geographic variation in long‐ versus short‐range sexual signals across a 3,500 + km transect of two related Australian field cricket species (Teleogryllus spp.): (a) selection for species recognition, (b) environmental adaptation and (c) stochastic divergence. We measured male calling song and male and female cuticular hydrocarbons (CHCs) in offspring derived from wild populations, reared under common garden conditions. Song clearly differentiated the species, and no hybrids were observed suggesting that hybridization is rare or absent. Spatial variation in song was not predicted by geography, genetics or climatic factors in either species. In contrast, CHC divergence was strongly associated with an environmental gradient supporting the idea that the climatic environment selects more directly upon these chemical signals. In light of recently advocated models of diversification via ecological selection on secondary sexual traits, the different environmental associations we found for song and CHCs suggest that the impact of ecological selection on population divergence, and how that influences speciation, might be different for acoustic versus chemical signals. 相似文献
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Cora E. Lewis John P. Bantle Alain G. Bertoni George Blackburn Frederick L. Brancati George A. Bray Lawrence J. Cheskin Jeffrey M. Curtis Caitlin Egan Mary Evans John P. Foreyt Siran Ghazarian Bethany Barone Gibbs Stephen P. Glasser Edward W. Gregg Helen P. Hazuda Louise Hesson James O. Hill Edward S. Horton Van S. Hubbard John M. Jakicic Robert W. Jeffery Karen C. Johnson Steven E. Kahn Abbas E. Kitabchi Dalane Kitzman William C. Knowler Edward Lipkin Sara Michaels Maria G. Montez David M. Nathan Ebenezer Nyenwe Jennifer Patricio Anne Peters Xavier Pi‐Sunyer Henry Pownall David M. Reboussin Donna H. Ryan Thomas A. Wadden Lynne E. Wagenknecht Holly Wyatt Rena R. Wing Susan Z. Yanovski 《Obesity (Silver Spring, Md.)》2020,28(2):247-258
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Habacuc Flores‐Moreno Farideh Fazayeli Arindam Banerjee Abhirup Datta Jens Kattge Ethan E. Butler Owen K. Atkin Kirk Wythers Ming Chen Madhur Anand Michael Bahn Chaeho Byun J. Hans C. Cornelissen Joseph Craine Andres Gonzalez‐Melo Wesley N. Hattingh Steven Jansen Nathan J. B. Kraft Koen Kramer Daniel C. Laughlin Vanessa Minden Ülo Niinemets Vladimir Onipchenko Josep Peuelas Nadejda A. Soudzilovskaia Rhiannon L. Dalrymple Peter B. Reich 《Global Ecology and Biogeography》2019,28(12):1806-1826
970.
Haijun Liu Hao Zhang Jeremy D. King Nathan R. Wolf Mindy Prado Michael L. Gross Robert E. Blankenship 《BBA》2014
The orange carotenoid protein (OCP), a member of the family of blue light photoactive proteins, is required for efficient photoprotection in many cyanobacteria. Photoexcitation of the carotenoid in the OCP results in structural changes within the chromophore and the protein to give an active red form of OCP that is required for phycobilisome binding and consequent fluorescence quenching. We characterized the light-dependent structural changes by mass spectrometry-based carboxyl footprinting and found that an α helix in the N-terminal extension of OCP plays a key role in this photoactivation process. Although this helix is located on and associates with the outside of the β-sheet core in the C-terminal domain of OCP in the dark, photoinduced changes in the domain structure disrupt this interaction. We propose that this mechanism couples light-dependent carotenoid conformational changes to global protein conformational dynamics in favor of functional phycobilisome binding, and is an essential part of the OCP photocycle. 相似文献