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排序方式: 共有5872条查询结果,搜索用时 15 毫秒
41.
Günther Klonner Johannes Wessely Andreas Gattringer Dietmar Moser Iwona Dullinger Karl Hülber Sabine B. Rumpf Svenja Block Oliver Bossdorf Marta Carboni Luisa Conti Wayne Dawson Emily Haeuser Martin Hermy Tamara Münkemüller Madalin Parepa Wilfried Thuiller Sebastiaan Van der Veken Kris Verheyen Mark van Kleunen Franz Essl Stefan Dullinger 《Ecography》2019,42(9):1548-1557
Climate warming is supposed to enlarge the area climatically suitable to the naturalization of alien garden plants in temperate regions. However, the effects of a changing climate on the spread of naturalized ornamentals have not been evaluated by spatially and temporarily explicit range modelling at larger scales so far. Here, we assess how climate change and the frequency of cultivation interactively determine the spread of 15 ornamental plants over the 21st century in Europe. We coupled species distribution modelling with simulations of demography and dispersal to predict range dynamics of these species in annual steps across a 250 × 250 m raster of the study area. Models were run under four scenarios of climate warming and six levels of cultivation intensity. Cultivation frequency was implemented as size of the area used for planting a species. Although the area climatically suitable to the 15 species increases, on average, the area predicted to be occupied by them in 2090 shrinks under two of the three climate change scenarios. This contradiction obviously arises from dispersal limitations that were pronounced although we assumed that cultivation is spatially adapting to the changing climate. Cultivation frequency had a much stronger effect on species spread than climate change, and this effect was non‐linear. The area occupied increased sharply from low to moderate levels of cultivation intensity, but levelled off afterwards. Our simulations suggest that climate warming will not necessarily foster the spread of alien garden plants in Europe over the next decades. However, climatically suitable areas do increase and hence an invasion debt is likely accumulating. Restricting cultivation of species can be effective in preventing species spread, irrespective of how the climate develops. However, for being successful, they depend on high levels of compliance to keep propagule pressure at a low level. 相似文献
42.
Functional consequences of cysteine modification in the ligand binding sites of peroxisome proliferator activated receptors by GW9662 总被引:21,自引:0,他引:21
43.
Top‐down control of species distributions: feral cats driving the regional extinction of a threatened rodent in northern Australia 下载免费PDF全文
44.
William H. Schlesinger L.A. Bruijnzeel Mark B. Bush Emily M. Klein Kimberly A. Mace Jane A. Raikes R.J. Whittaker 《Biogeochemistry》1998,40(1):37-55
This study examined the accumulation of organic carbon (C) and fractions ofsoil phosphorus (P) in soils developing in volcanic ash deposited in the1883 eruption of Krakatau. Organic C has accumulated at rates of 45 to 127g/m2/yr during 110 years of soil development, resulting inprofiles with as much as 14 kgC/m2. Most soil P is found inthe HCl-extractable forms, representing apatite. A loss of HCl-extractableP from the surface horizons is associated with a marked accumulation ofNaOH-extractable organic P bound to Al. A bioassay with hill rice suggeststhat P is limiting to plant growth in these soils, perhaps as a result ofthe rapid accumulation of P in organic forms. 相似文献
45.
Huisman FH Koon N Bulloch EM Baker HM Baker EN Squire CJ Parker EJ 《Biochemistry》2012,51(11):2289-2297
α-Isopropylmalate synthase (α-IPMS) catalyzes the metal-dependent aldol reaction between α-ketoisovalerate (α-KIV) and acetyl-coenzyme A (AcCoA) to give α-isopropylmalate (α-IPM). This reaction is the first committed step in the biosynthesis of leucine in bacteria. α-IPMS is homodimeric, with monomers consisting of (β/α)(8) barrel catalytic domains fused to a C-terminal regulatory domain, responsible for binding leucine and providing feedback regulation for leucine biosynthesis. In these studies, we demonstrate that removal of the regulatory domain from the α-IPMS enzymes of both Neisseria meningitidis (NmeIPMS) and Mycobacterium tuberculosis (MtuIPMS) results in enzymes that are unable to catalyze the formation of α-IPM, although truncated NmeIPMS was still able to slowly hydrolyze AcCoA. The lack of catalytic activity of these truncation variants was confirmed by complementation studies with Escherichia coli cells lacking the α-IPMS gene, where transformation with the plasmids encoding the truncated α-IPMS enzymes was not able to rescue α-IPMS activity. X-ray crystal structures of both truncation variants reveal that both proteins are dimeric and that the catalytic sites of the proteins are intact, although the divalent metal ion that is thought to be responsible for activating substrate α-KIV is displaced slightly relative to its position in the substrate-bound, wild-type structure. Isothermal titration calorimetry and WaterLOGSY nuclear magnetic resonance experiments demonstrate that although these truncation variants are not able to catalyze the reaction between α-KIV and AcCoA, they are still able to bind the substrate α-KIV. It is proposed that the regulatory domain is crucial for ensuring protein dynamics necessary for competent catalysis. 相似文献
46.
47.
Emily L. Bruns Ian Miller Michael E. Hood Valentina Carasso Janis Antonovics 《Evolution; international journal of organic evolution》2019,73(3):497-510
In flowering plants, the evolution of females is widely hypothesized to be the first step in the evolutionary pathway to separate male and female sexes, or dioecy. Natural enemies have the potential to drive this evolution if they preferentially attack hermaphrodites over females. We studied sex‐based differences in exposure to anther‐smut (Microbotryum), a sterilizing pollinator‐transmitted disease, in Dianthus pavonius, a gynodioecious perennial herb. We found that within a heavily diseased population, females consistently had lower levels of Microbotryum spore deposition relative to hermaphrodites and that this difference was driven by rapid floral closing in females following successful pollination. We further show that this protective closing behavior is frequency dependent; females close faster when they are rare. These results indicate that anther‐smut disease is an important source of selection for females, especially since we found in a common garden experiment no evidence that females have any inherent fecundity advantages over hermaphrodites. Finally, we show that among populations, those where anther‐smut is present have a significantly higher frequency of females than those where the disease is absent. Taken together our results indicate that anther‐smut disease is likely an important biotic factor driving the evolution and maintenance of females in this gynodioecious species. 相似文献
48.
Effects of thyroxine exposure on the Twist 1 +/− phenotype: A test of gene–environment interaction modeling for craniosynostosis 下载免费PDF全文
49.
Rui Faria Pragya Chaube Hernn E. Morales Tomas Larsson Alan R. Lemmon Emily M. Lemmon Marina Rafajlovi Marina Panova Mark Ravinet Kerstin Johannesson Anja M. Westram Roger K. Butlin 《Molecular ecology》2019,28(6):1375-1393
Both classical and recent studies suggest that chromosomal inversion polymorphisms are important in adaptation and speciation. However, biases in discovery and reporting of inversions make it difficult to assess their prevalence and biological importance. Here, we use an approach based on linkage disequilibrium among markers genotyped for samples collected across a transect between contrasting habitats to detect chromosomal rearrangements de novo. We report 17 polymorphic rearrangements in a single locality for the coastal marine snail, Littorina saxatilis. Patterns of diversity in the field and of recombination in controlled crosses provide strong evidence that at least the majority of these rearrangements are inversions. Most show clinal changes in frequency between habitats, suggestive of divergent selection, but only one appears to be fixed for different arrangements in the two habitats. Consistent with widespread evidence for balancing selection on inversion polymorphisms, we argue that a combination of heterosis and divergent selection can explain the observed patterns and should be considered in other systems spanning environmental gradients. 相似文献
50.