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41.
STEPHEN J. THACKERAY TIMOTHY H. SPARKS MORTEN FREDERIKSEN SARAH BURTHE PHILIP J. BACON JAMES R. BELL MARC S. BOTHAM TOM M. BRERETON PAUL W. BRIGHT LAURENCE CARVALHO TIM CLUTTON‐BROCK ALISTAIR DAWSON MARTIN EDWARDS J. MALCOLM ELLIOTT RICHARD HARRINGTON DAVID JOHNS IAN D. JONES JAMES T. JONES DAVID I. LEECH DAVID B. ROY W. ANDY SCOTT MATT SMITH RICHARD J. SMITHERS IAN J. WINFIELD SARAH WANLESS 《Global Change Biology》2010,16(12):3304-3313
Recent changes in the seasonal timing (phenology) of familiar biological events have been one of the most conspicuous signs of climate change. However, the lack of a standardized approach to analysing change has hampered assessment of consistency in such changes among different taxa and trophic levels and across freshwater, terrestrial and marine environments. We present a standardized assessment of 25 532 rates of phenological change for 726 UK terrestrial, freshwater and marine taxa. The majority of spring and summer events have advanced, and more rapidly than previously documented. Such consistency is indicative of shared large scale drivers. Furthermore, average rates of change have accelerated in a way that is consistent with observed warming trends. Less coherent patterns in some groups of organisms point to the agency of more local scale processes and multiple drivers. For the first time we show a broad scale signal of differential phenological change among trophic levels; across environments advances in timing were slowest for secondary consumers, thus heightening the potential risk of temporal mismatch in key trophic interactions. If current patterns and rates of phenological change are indicative of future trends, future climate warming may exacerbate trophic mismatching, further disrupting the functioning, persistence and resilience of many ecosystems and having a major impact on ecosystem services. 相似文献
42.
MARC I. FÖRSCHLER JUAN CARLOS SENAR ANTONI BORRAS JOSEP CABRERA MATS BJÖRKLUND 《Biological journal of the Linnean Society. Linnean Society of London》2011,103(3):707-721
We studied gene flow and bottleneck events in the population history of locally isolated citril finches endemic to European mountains. For the present study, we used two genetic markers with different rates of evolution: a fast evolving mitochondrial marker (ATPase6/8) and a more slowly evolving nuclear marker (02401). Populations north of the Pyrenees showed in general fewer haplotypes and a considerable lower nucleotide and gene diversity than the Iberian populations. Unexpectedly, we found very little genetic variability in the fast evolving mitochondrial marker, arguing for a strong and relatively recent bottleneck event in the species population history. This pattern potentially reflects a sudden decrease of crucial resources during Mid‐Holocene (mountain pine, Scots pine, and black pine) and a subsequent breakdown of the population. The bottleneck could also have been caused or coincide with a selective sweep in the mitochondrion. By contrast, the slowly evolving nuclear marker showed a much higher variability. This marker probably reflects major gene flow along a potential expansion pathway from the Eastern Pyrenees, northwards to the populations of Central Europe, and southwards to the more fragmented populations of central and southern Spain. The population of the Western Pyrenees (Navarra) appears to be cut‐off from this major gene flow and our data indicate a certain degree of partial isolation, probably reflecting more ancient events (e.g. the separation in distinct refuge sites during the last glacial maximum). © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 707–721. 相似文献
43.
Mercator: a fast and simple web server for genome scale functional annotation of plant sequence data
MARC LOHSE AXEL NAGEL THOMAS HERTER PATRICK MAY MICHAEL SCHRODA RITA ZRENNER TAKAYUKI TOHGE ALISDAIR R. FERNIE MARK STITT BJÖRN USADEL 《Plant, cell & environment》2014,37(5):1250-1258
Next‐generation technologies generate an overwhelming amount of gene sequence data. Efficient annotation tools are required to make these data amenable to functional genomics analyses. The Mercator pipeline automatically assigns functional terms to protein or nucleotide sequences. It uses the MapMan ‘BIN’ ontology, which is tailored for functional annotation of plant ‘omics’ data. The classification procedure performs parallel sequence searches against reference databases, compiles the results and computes the most likely MapMan BINs for each query. In the current version, the pipeline relies on manually curated reference classifications originating from the three reference organisms (Arabidopsis, Chlamydomonas, rice), various other plant species that have a reviewed SwissProt annotation, and more than 2000 protein domain and family profiles at InterPro, CDD and KOG. Functional annotations predicted by Mercator achieve accuracies above 90% when benchmarked against manual annotation. In addition to mapping files for direct use in the visualization software MapMan, Mercator provides graphical overview charts, detailed annotation information in a convenient web browser interface and a MapMan‐to‐GO translation table to export results as GO terms. Mercator is available free of charge via http://mapman.gabipd.org/web/guest/app/Mercator . 相似文献
44.
1. Arthropod performance is a non‐linear function of temperature, and thus global climate change may impact arthropods in a variety of non‐obvious ways. 2. In this paper, the well‐known thermal performance curve is reviewed briefly and attention is drawn to the importance of variance in temperature, particularly major weather events such as cold snaps and heatwaves. 3. A model is developed that considers the asymmetry between cold and heat stress and, particularly, the different timescales of recovery from these stressors: near‐instantaneous for cold and lagged effects from heat. 4. Growth rate is evaluated as a function of weather‐event intensity and length. Including the timescale asymmetry exacerbates both heat stress and, to a much lesser degree, cold stress. 相似文献
45.
Evidence for mate‐encounter Allee effect in an invasive longhorn beetle (Coleoptera: Cerambycidae)
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MARC RHAINDS STEPHEN B. HEARD CORY HUGHES WAYNE MACKINNON KEVIN PORTER JON SWEENEY PETER SILK IAN DEMERCHANT SARAH MCLEAN GARRETT BRODERSEN 《Ecological Entomology》2015,40(6):829-832
1. Limited empirical support is available for mate‐encounter Allee effects in invasive insects due to the logistical challenges of studying demographic trends in low‐density populations. 2. Traps baited with pheromone and spruce volatiles were used to monitor the abundance of female Tetropium fuscum F. (Coleoptera: Cerambycidae) at multiple sites in Nova Scotia in 2011 and 2012. Each female was dissected to determine the presence or absence of sperm in its spermatheca (mated or virgin female, respectively). 3. Both male and total T. fuscum abundance declined with increasing distance to the focal point of T. fuscum's invasion. Female mating probability declined with male abundance and with distance from the invasion focus, and mating probabilities were very low at the most peripheral sites. Difficulty in encountering mates may thus contribute to limiting the spread of T. fuscum. 4. The approach outlined here could be integrated into existing surveys of wood borers using traps baited with semiochemicals to improve our understanding of the role of the mate‐encounter Allee effect in invasion dynamics. 相似文献
46.
Methanol Accumulation in Maturing Seeds 总被引:6,自引:2,他引:4
OBENDORF RALPH L.; KOCH JAMES L.; GORECKI RYSZARD J; AMABLE RICHARD A.; AVENI MARC T. 《Journal of experimental botany》1990,41(4):489-495
During in vitro growth and maturation of soybean seeds, cessationof embryo growth and dry weight accumulation occurred in thepresence of abundant C and N nutrients. Axis followed by cotyledontissues changed from green to yellow, and post-harvest germinationpotential declined if cultured after yellowing of axis tissues.A tissue specific accumulat;on of methanol occurred during thein vitro culture of immature seeds (i.e. initially 50 to 70mg fresh weight) to maturity in liquid medium. Methanol accumulatedto 3.0 g m3 or 50 µg seed1 in the medium,while methanol decreased from 37 to about 3.0 µg g1fresh weight in cotyledons. By contrast, axis tissues increased20-fold in methanol concentration to 90 µg g1 during20 d in culture. Ethanol was present only in trace amounts inaxis tissues and medium. Addition of exogenous methanol vapourto in situ grown seeds during precocious maturation decreasedsubsequent seedling vigour and germination with increasing levelsof exposure. Methanol accumulation in axis tissues during thegermination phase was not correlated with high temperature andtissue water content treatments which simulated pre-harvestdeterioration of seeds. However, the accumulation of methanolduring in vitro seed development and maturation in liquid culturemay contribute to reduced post-harvest germination performance. Key words: Soybean, Glycine max, seed maturation, in vitro, methanol 相似文献
47.
NICOLAS S. Piuzzi MASSIMO DOMINICI MARC LONG CECILIA PASCUAL-GARRIDO SCOTT RODEO JOHNNY HUARD JÉROME GUICHEUX RICHARD MCFARLAND LAURIE R. GOODRICH STÉPHANE MADDENS PAMELA G. ROBEY THOMAS W BAUER JOHN BARRETT FRANK BARRY DAVID KARLI CONSTANCE R. CHU DANIEL J. WEISS IVAN MARTIN GEORGE F. MUSCHLER 《Cytotherapy》2018,20(11):1381-1400
The Signature Series Symposium “Cellular Therapies for Orthopaedics and Musculoskeletal Disease Proven and Unproven Therapies—Promise, Facts and Fantasy” was held as a pre-meeting of the 26th International Society for Cellular Therapy (ISCT) annual congress in Montreal, Canada, May 2, 2018. This was the first ISCT program that was entirely dedicated to the advancement of cell-based therapies for musculoskeletal diseases. Cellular therapies in musculoskeletal medicine are a source of great promise and opportunity. They are also the source of public controversy, confusion and misinformation. Patients, clinicians, scientists, industry and government share a commitment to clear communication and responsible development of the field. Therefore, this symposium convened thought leaders from around the world in a forum designed to catalyze communication and collaboration to bring the greatest possible innovation and value to patients with musculoskeletal conditions. 相似文献
48.
GIANCARLO A. BIAGINI MARC T. E. SULLER BLAND J. FINLAY DAVID LLOYD 《The Journal of eukaryotic microbiology》1997,44(5):447-453
ABSTRACT. The free-living anaerobic flagellate Hexamita sp. was observed to actively consume O2 with a Km O2 of 13 μM. Oxygen consumption increased lineraly with O2 tension up to a threshold level of 100 μM, above which it was inhibited. Oxygen uptake was supported by a number of substrates but probably not coupled to energy conservation as cytochromes could not be detected spectro-photometrically. In addition, inhibitors specific for respiratory chain components did not significantly affect O2 uptake. Respiration was however, partially inhibited by flavoprotein and iron-sulfur protein inhibitors. NAD(P)H supported O2 consumption was measured in both particulate and soluble fractions; this activity was partially inhibited by quinacrine. A chemosensory response was observed in cells exposed to air, however no response was observed in the presence of superoxide dismutase plus catalase. Catalase and nonspecific peroxidase activity could not be detected, but superoxide dismutase activity was present. Superoxide dismutase was sensitive to NaN3 and H2O2 but not KCN, suggesting a Fe prosthetic group. Flow cytometric analysis revealed that thiol levels in live cells were depleted in the presence of t-butyl H2O2. The observed NADPH-driven glutathione reductase activity is believed to recycle oxidized thiols in order to re-establish reduced thiol levels in the cell. The corresponding thiol cycling enzyme glutathione peroxidase could not be detected. The ability to withstand high O2 tensions (100 μM) would enable Hexamita to spend short periods in a wider range of habitats. Prologed exposure to O2 tensions higher than 100 μM leads to irreversible damage and cell death. 相似文献
49.
DAVID A. PEPPER PETER E. ELIASSON ROSS E. McMURTRIE MARC CORBEELS GÖRAN I. ÅGREN MONIKA STRÖMGREN SUNE LINDER 《Global Change Biology》2007,13(6):1265-1281
An improved understanding of the response of forest ecosystems to elevated levels of CO2 in the atmosphere is crucial because atmospheric CO2 concentration continues to increase at an accelerating rate and forests are an important sink in the global carbon cycle. Several CO2‐enrichment experiments have now been running for more than 10 years, with highly variable short‐term results after the first decade. Responses to rising [CO2] over the next few decades will depend on several plant and ecosystem feedbacks that are inadequately understood. In this study, we conduct a sensitivity analysis, within the context of the simulated CO2 response, using a new version of the G'DAY ecosystem model, with an improved decomposition submodel, applied to a nitrogen‐limited Norway spruce forest site in the north of Sweden. The new decomposition model incorporates important modifications to soil processes, including some that constitute negative feedbacks on an ecosystem's growth response to elevated [CO2]. The sensitivity analysis reveals key parameters and processes that are important for the simulated CO2 response on the short term and others that are more important on the long term. A process that has a strong impact on the short‐term response is a change in decomposer composition, potentially in response to altered litter quality. Parameters that become increasingly important in the long term are carbon allocation to root exudates that are directly or indirectly associated with atmospheric N2 fixation, and the rate of humification of soil organic matter. We identify factors intrinsic to species and site (microbes and resources) and ecosystem nutrient supply that determine the duration of the enhanced simulated growth response to elevated [CO2]. 相似文献
50.
JACQUES DUPOUY DIDIER ROUSSEAU GEORGES DUSSART F.L.S. MARC VIANEY LIAUD HENRI NASSI 《Biological journal of the Linnean Society. Linnean Society of London》1993,50(4):329-338
A correspondence analysis of shell measurements taken from 521 widely dispersed specimens of the African aquatic pulmonate snail Biomphalaria pfeifferi suggests the existence of eight morphological groups. These groups appear to relate to either ecophysiological factors or to factors associated with the stability of the freshwater system rather than to aspects of geographic distribution and genetic isolation. 相似文献