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21.
22.
Identification and expression of water stress- and abscisic acid-regulated genes in a drought-tolerant sunflower genotype 总被引:17,自引:0,他引:17
23.
Anne-Catherine Schmit Virginie Stoppin Véronique Chevrier Didier Job Anne-Marie Lambert 《Chromosoma》1994,103(5):343-351
Compelling evidence has been obtained in favour of the idea that the nuclear surface of higher plant cells is a microtubule-nucleating and/or organizing site (MTOC), in the absence of defined centrosomes. How these plant MTOC proteins are redistributed and function during the progression of the cell cycle remains entirely unknown. Using a monoclonal antibody (mAb 6C6) raised against isolated calf thymus centrosomes and showing apparent reaction with the plant nuclear surface, we followed the targeted antigen distribution during mitosis and meiosis of higher plants. Immunoblot analysis of protein fractions from Allium root meristematic cell extracts probed with mAb 6C6 reveals a polypeptide of an apparent Mr of 78000. In calf centrosome extracts, a polypeptide of comparable molecular mass is found in addition to a major antigen of Mr 180000 after mAb 6C6 immunoblotting. During mitotic initiation, the plant antigen is prominent on the periphery of the prophase nucleus. When the nuclear envelope breaks down, the antigen suddenly becomes associated with the centromere-kinetochores until late anaphase. In telophase, when the nuclear envelope is being reconstructed, it is no longer detected at the kinetochores but is solely associated again with the nuclear surface. This antigen displays a unique spatial and temporal distribution, which may reflect the pathway of plant protein(s) between the nuclear surface and the kinetochores under cell cycle control. So far, such processes have not been described in higher plant cells. These observations shed light on the putative activity of the plant kinetochore as a protein transporter. They also suggest that a plant centrosome-like antigen may have different cytoskeletal related functions depending on cell cycle regulated changes in its subcellular distribution.Abbreviations mAb
monoclonal antibody
- MSB
microtubule stabilizing buffer
- TBS
Tris buffered saline
- MTOC
microtubule organizing centre 相似文献
24.
25.
Drosophila melanogaster acetylcholinesterase: Identification and expression of two mutations responsible for cold- and heat-sensitive phenotypes 总被引:2,自引:0,他引:2
Annick Mutero Jean-Marc Bride Madeleine Pralavorio Didier Fournier 《Molecular & general genetics : MGG》1994,243(6):699-705
Ace
IJ29 and Ac
IJ40 are cold- and heat-sensitive variants of the gene coding for acetylcholinesterase in Drosophila melanogaster. In the homozygous condition, these mutations are lethal when animals are raised at restrictive temperatures, i.e., below 23° C for Ace
IJ29 or above 25° C for Ace
IJ40. The coding regions of the gene in these mutants were sequenced and mutations changing Ser374 to Phe in Ace
IJ29 and Pro75 to Leu in Ace
IJ40 were found. Acetylcholinesterases bearing these mutations were expressed in Xenopus oocytes and we found that these mutations decrease the secretion rate of the protein most probably by affecting its folding. This phenomenon is exacerbated at restrictive temperatures decreasing the amount of secreted acetylcholinesterase below the lethality threshold. In parallel, the substitution of the conserved Asp248 by an Asn residue completely inhibits the activity of the enzyme and its secretion, preventing the correct folding of the protein in a non-conditional manner. 相似文献
26.
Giovanni Sgubin Didier Swingedouw Juliette Mignot Gregory Alan Gambetta Benjamin Bois Harilaos Loukos Thomas Noël Philippe Pieri Iñaki García de Cortázar-Atauri Nathalie Ollat Cornelis van Leeuwen 《Global Change Biology》2023,29(3):808-826
Evaluating the potential climatic suitability for premium wine production is crucial for adaptation planning in Europe. While new wine regions may emerge out of the traditional boundaries, most of the present-day renowned winemaking regions may be threatened by climate change. Here, we analyse the future evolution of the geography of wine production over Europe, through the definition of a novel climatic suitability indicator, which is calculated over the projected grapevine phenological phases to account for their possible contractions under global warming. Our approach consists in coupling six different de-biased downscaled climate projections under two different scenarios of global warming with four phenological models for different grapevine varieties. The resulting suitability indicator is based on fuzzy logic and is calculated over three main components measuring (i) the timing of the fruit physiological maturity, (ii) the risk of water stress and (iii) the risk of pests and diseases. The results demonstrate that the level of global warming largely determines the distribution of future wine regions. For a global temperature increase limited to 2°C above the pre-industrial level, the suitable areas over the traditional regions are reduced by about 4%/°C rise, while for higher levels of global warming, the rate of this loss increases up to 17%/°C. This is compensated by a gradual emergence of new wine regions out of the traditional boundaries. Moreover, we show that reallocating better-suited grapevine varieties to warmer conditions may be a viable adaptation measure to cope with the projected suitability loss over the traditional regions. However, the effectiveness of this strategy appears to decrease as the level of global warming increases. Overall, these findings suggest the existence of a safe limit below 2°C of global warming for the European winemaking sector, while adaptation might become far more challenging beyond this threshold. 相似文献
27.
28.
29.
Spatial structure of mitochondria and ER denotes changes in cell physiology of cultured tobacco protoplasts 总被引:7,自引:3,他引:4
Didier Stickens Jean-Pierre Verbelen 《The Plant journal : for cell and molecular biology》1996,9(1):85-92
The structure of mitochondria and of the endoplasmic reticulum (ER) in mesophyll protoplasts and regenerated cells was studied in vivo using the dye DiOC6 (3) (3,3'-dihexyloxacarbocyanine iodide) and confocal laser scanning microscopy (CLSM). The relation to the cell's physiology was investigated using a hormone-based model system for elongation and division. The structure of the mitochondria and of their population depends on the status of the cell. In freshly isolated protoplasts small spherical mitochondria are clustered around the nucleus and the chloroplasts. During the first 4 days of culture they are transformed into long vermiform organelles which distribute evenly throughout the cytoplasm. In a medium containing only auxins, cells then enter a period of expansion. Their mitochondria retain the same structure but increase in quantity. In a medium with auxins and cytokinins cells start dividing. Their mitochondria typically become numerous and very small, and are distributed throughout the cytoplasm. Both types of organization were observed during weeks of ongoing expansion or division. The ER is always present as a network close to the cell membrane. In freshly isolated protoplasts a considerable part of the ER is clustered around the chloroplasts, the remaining part of the network has a reduced complexity and is partly broken. During subsequent protoplast culture the network grows into a complex web with fine meshes incorporating lots of plate-like structures. This is the case in elongating cells as well as in dividing cells. Finally, the ER looks similar to the structure found in epidermal cells of the intact plant. 相似文献
30.
In this study, the role of root organic acid synthesis and exudation in the mechanism of aluminum tolerance was examined in Al-tolerant (South American 3) and Al-sensitive (Tuxpeño and South American 5) maize genotypes. In a growth solution containing 6 M Al3+, Tuxpeño and South American 5 were found to be two- and threefold more sensitive to Al than South American 3. Root organic acid content and organic acid exudation from the entire root system into the bulk solution were investigated via high-performance liquid chromatographic analysis while exudates collected separately from the root apex or a mature root region (using a dividedroot-chamber technique) were analyzed with a more-sensitive ion chromatography system. In both the Al-tolerant and Al-sensitive lines, Al treatment significantly increased the total root content of organic acids, which was likely the result of Al stress and not the cause of the observed differential Al tolerance. In the absence of Al, small amounts of citrate were exuded into the solution bathing the roots. Aluminum exposure triggered a stimulation of citrate release in the Al-tolerant but not in the Al-sensitive genotypes; this response was localized to the root apex of the Al-tolerant genotype. Additionally, Al exposure triggered the release of phosphate from the root apex of the Al-tolerant genotype. The same solution Al3+ activity that elicited the maximum difference in Al sensitivity between Al-tolerant and Al-sensitive genotypes also triggered maximal citrate release from the root apex of the Al-tolerant line. The significance of citrate as a potential detoxifier for aluminum is discussed. It is concluded that organic acid release by the root apex could be an important aspect of Al tolerance in maize.Abbreviations SA3
South American 3, an Al-tolerant maize cultivar
- SA5
South American 5, an Al-sensitive maize cultivar
The authors would like to express their appreciation to Drs. John Thompson, Ross Welch and Mr. Stephen Schaefer for their training and guidance in the use of the chromatography systems. This work was supported by a Swiss National Science Foundation Fellowship to Didier Pellet, and U.S. Department of Agriculture/National Research Initiative Competitive Grant 93-37100-8874 to Leon Kochian. We would also like to thank Drs. S. Pandey and E. Ceballos from the CIMMYT Regional office at CIAT Cali, Colombia for providing seed for the maize varieties and inbred line. 相似文献