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Hans-Jochen Schfer Gabriele Rathgeber Achim Schuhen Richard J. Berzborn 《FEBS letters》1994,340(3):265-268
UV irradiation of the ATPase (CF1) from spinach chloroplasts in the presence of 3'-arylazido-β-alanyl-8-azido ATP (8,3'-DiN3ATP) results in a nucleotide-dependent inactivation of the enzyme and in a nucleotide-dependent formation of -β cross-links. The results demonstrate an interfacial localization of the nucleotide binding sites on CF1. 相似文献
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Natural forests are characterised by a high level of both spatial and temporal heterogeneity. The major processes involved in the creation and maintenance of forest heterogeneity in temperate climates are small-sized canopy disturbances. The resulting openings also modify the growth conditions for the remaining trees. The analysis of tree growth responses using dendrochronological techniques allows the reconstruction of the time sequence of the disturbances. The radial growth analysis is coupled here with both a spatial analysis and a demographic analysis of the forest structure. The age classes are temporally organised in cohorts and spatially distributed in spatial aggregates. The analysis of the most documented disturbance event allowed us to determine the size of the disturbance response patch (between 0.036 and 0.073 ha) and the duration of the disturbance (six years). We considered that this small-scale disturbance event may have been caused by the fall of a single tree and has freed the surrounding trees of its competition. 相似文献
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A new hybrid humidity sensor comprising a conventional capacitance humidity sensor and a planar heating element is described. Owing to its short response time of only a few milliseconds, its great measuring accuracy, large measuring range, and simplicity in handling, the sensor is suitable for measuring water vapour partial pressure in gases with rapidly changing flow and direction, e.g. in ventilated patients in the fields of anaesthesia and intensive care medicine. The small dimensions permit measurements at almost any location within the ventilation system. 相似文献
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UV-induced cross-linking of Tet repressor to DNA containing tet operator sequences and 8-azidoadenines. 总被引:2,自引:2,他引:0 下载免费PDF全文
The synthesis of 8-azido-2'-deoxyadenosine-5'-triphosphate is described. The photoreactive dATP analog was characterized by thin layer chromatography, proton resonance spectroscopy, infrared spectroscopy and UV spectroscopy. Its photolysis upon UV irradiation was studied. After incorporation of this dATP analog into DNA containing the tet operator sequence the investigation of the interactions between tet operator DNA and Tet repressor protein by UV photocross-linking becomes possible. Photocross-linking of protein to DNA was demonstrated by the reduced migration of the DNA in SDS polyacrylamide gel electrophoresis. Addition of the inducer tetracycline prior to UV irradiation significantly reduces the DNA-protein cross-linking rate. The long wave UV light applied here does not significantly alter the DNA or the protein under the photocross-linking conditions. 相似文献
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Rathgeber C Yurkova N Stackebrandt E Schumann P Humphrey E Beatty JT Yurkov V 《Current microbiology》2006,53(5):449-456
Five strains of Gram-negative, rod, curved rod and spiral-shaped bacteria were isolated from the vicinity of deep ocean hydrothermal
vents along the Main Endeavour Segment of the Juan de Fuca Ridge in the Pacific Ocean. All strains showed remarkable resistance
to high levels of toxic metalloid oxyanions, and were capable of reducing the oxyanions tellurite and selenite to their less
toxic elemental forms. Phylogenetic analysis of four strains identified these isolates as close relatives of the genus Pseudoalteromonas within the class Gammaproteobacteria. Pseudoalteromonas agarivorans was the closest relative of strains Te-1-1 and Se-1-2-redT, with, respectively, 99.5 and 99.8% 16S rDNA sequence similarity. Strain Te-2-2T was most closely related to Pseudoalteromonas paragorgicola, with 99.8% 16S rDNA sequence similarity. The DNA G+C base composition was 39.6 to 41.8 mol%, in agreement with other members
of the genus Pseudoalteromonas. However, the isolates showed important morphological and physiological differences from previously described species of
this genus, with one group forming rod-shaped bacteria typical of Pseudoalteromonas and the other forming vibrioid- to spiral-shaped cells. Based on these differences, and on phylogenetic data, we propose
the creation of the new species Pseudoalteromonas telluritireducens sp. nov., with strain Se-1-2-redT (DSMZ=16098T=VKM B-2382T) as the type strain, and Pseudoalteromonas spiralis sp. nov., with strain Te-2-2T (DSMZ=16099T=VKM B-2383T) as the type strain.
The EMBL accession numbers for the 16S rDNA sequences are: Te-1-1, AJ314843; Te-2-2T, AJ314842; Se-1-2-or, AJ314844; Se-1-2-redT, AJ314845. 相似文献
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Bioclimatic model of tree radial growth: application to the French Mediterranean Aleppo pine forests
Cyrille B. K. Rathgeber Laurent Misson Antoine Nicault Joël Guiot 《Trees - Structure and Function》2005,19(2):162-176
The potential effects of global changes on forests are of increasing concern. Dendrochronology, which deals with long-term records of tree growth under natural environmental conditions, can be used to evaluate the impact of climatic change on forest productivity. However, assessment of climatic change impacts must be supported by accurate and reliable models of the relationships between climate and tree growth. In this study, a bioclimatic model is used to explore the relationships between tree radial growth and bioclimatic variables closely related to the biological functioning of a tree. This model is at an intermediate level of complexity between purely empirical and process-based models. The method is illustrated with data for 21 Aleppo pine (Pinus halepensis Mill.) stands grown under a Mediterranean climate in south-east France. The results show that Aleppo pine growth is mainly controlled by soil water availability during the growing season. The bioclimatic variable which best expresses the observed inter-annual tree growth variations is the actual evapotranspiration (AET). Four parameters were adjusted to simulate dendrochronological data: the soil water capacity, the wilting point, the minimum temperature for photosynthesis, and the end of the growing season. The bioclimatic model gives better results than the standard response function and provides better insight into the functional processes involved in tree growth. The convincing results obtained by the bioclimatic model as well as the limited numbers of parameters it requires demonstrate the feasibility of using it to explore future climatic change impacts on Aleppo pine forests. 相似文献
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Martin de Luis Katarina ?ufar Alfredo Di Filippo Klemen Novak Andreas Papadopoulos Gianluca Piovesan Cyrille B. K. Rathgeber José Raventós Miguel Angel Saz Kevin T. Smith 《PloS one》2013,8(12)
We investigated the variability of the climate-growth relationship of Aleppo pine across its distribution range in the Mediterranean Basin. We constructed a network of tree-ring index chronologies from 63 sites across the region. Correlation function analysis identified the relationships of tree-ring index to climate factors for each site. We also estimated the dominant climatic gradients of the region using principal component analysis of monthly, seasonal, and annual mean temperature and total precipitation from 1,068 climatic gridpoints. Variation in ring width index was primarily related to precipitation and secondarily to temperature. However, we found that the dendroclimatic relationship depended on the position of the site along the climatic gradient. In the southern part of the distribution range, where temperature was generally higher and precipitation lower than the regional average, reduced growth was also associated with warm and dry conditions. In the northern part, where the average temperature was lower and the precipitation more abundant than the regional average, reduced growth was associated with cool conditions. Thus, our study highlights the substantial plasticity of Aleppo pine in response to different climatic conditions. These results do not resolve the source of response variability as being due to either genetic variation in provenance, to phenotypic plasticity, or a combination of factors. However, as current growth responses to inter-annual climate variability vary spatially across existing climate gradients, future climate-growth relationships will also likely be determined by differential adaptation and/or acclimation responses to spatial climatic variation. The contribution of local adaptation and/or phenotypic plasticity across populations to the persistence of species under global warming could be decisive for prediction of climate change impacts across populations. In this sense, a more complex forest dynamics modeling approach that includes the contribution of genetic variation and phenotypic plasticity can improve the reliability of the ecological inferences derived from the climate-growth relationships. 相似文献
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Nicolas Delpierre Sgolne Lireux Florian Hartig Jesus Julio Camarero Alissar Cheaib Katarina ufar Henri Cuny Annie Deslauriers Patrick Fonti Joica Gri
ar Jian‐Guo Huang Cornelia Krause Guohua Liu Martin de Luis Harri Mkinen Edurne Martinez del Castillo Hubert Morin Pekka Njd Walter Oberhuber Peter Prislan Sergio Rossi Seyedeh Masoumeh Saderi Vaclav Treml Hanus Vavrick Cyrille B. K. Rathgeber 《Global Change Biology》2019,25(3):1089-1105
The phenology of wood formation is a critical process to consider for predicting how trees from the temperate and boreal zones may react to climate change. Compared to leaf phenology, however, the determinism of wood phenology is still poorly known. Here, we compared for the first time three alternative ecophysiological model classes (threshold models, heat‐sum models and chilling‐influenced heat‐sum models) and an empirical model in their ability to predict the starting date of xylem cell enlargement in spring, for four major Northern Hemisphere conifers (Larix decidua, Pinus sylvestris, Picea abies and Picea mariana). We fitted models with Bayesian inference to wood phenological data collected for 220 site‐years over Europe and Canada. The chilling‐influenced heat‐sum model received most support for all the four studied species, predicting validation data with a 7.7‐day error, which is within one day of the observed data resolution. We conclude that both chilling and forcing temperatures determine the onset of wood formation in Northern Hemisphere conifers. Importantly, the chilling‐influenced heat‐sum model showed virtually no spatial bias whichever the species, despite the large environmental gradients considered. This suggests that the spring onset of wood formation is far less affected by local adaptation than by environmentally driven plasticity. In a context of climate change, we therefore expect rising winter–spring temperature to exert ambivalent effects on the spring onset of wood formation, tending to hasten it through the accumulation of forcing temperature, but imposing a higher forcing temperature requirement through the lower accumulation of chilling. 相似文献