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Roy J, Rineau F, De Boeck HJ, Nijs I, Pütz T, Abiven S, Arnone JA, Barton CVM, Beenaerts N, Brüggemann N, Dainese M, Domisch T, Eisenhauer N, Garré S, Gebler A, Ghirardo A, Jasoni RL, Kowalchuk G, Landais D, Larsen SH, Leemans V, Le Galliard J, Longdoz B, Massol F, Mikkelsen TN, Niedrist G, Piel C, Ravel O, Sauze J, Schmidt A, Schnitzler J, Teixeira LH, Tjoelker MG, Weisser WW, Winkler B, Milcu A. Ecotrons: Powerful and versatile ecosystem analysers for ecology, agronomy and environmental science. Glob Chang Biol 2021; 27:1387-1407. [PMID: 33274502 PMCID: PMC7986626 DOI: 10.1111/gcb.15471] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 05/08/2023]
Abstract
Ecosystems integrity and services are threatened by anthropogenic global changes. Mitigating and adapting to these changes require knowledge of ecosystem functioning in the expected novel environments, informed in large part through experimentation and modelling. This paper describes 13 advanced controlled environment facilities for experimental ecosystem studies, herein termed ecotrons, open to the international community. Ecotrons enable simulation of a wide range of natural environmental conditions in replicated and independent experimental units while measuring various ecosystem processes. This capacity to realistically control ecosystem environments is used to emulate a variety of climatic scenarios and soil conditions, in natural sunlight or through broad-spectrum lighting. The use of large ecosystem samples, intact or reconstructed, minimizes border effects and increases biological and physical complexity. Measurements of concentrations of greenhouse trace gases as well as their net exchange between the ecosystem and the atmosphere are performed in most ecotrons, often quasi continuously. The flow of matter is often tracked with the use of stable isotope tracers of carbon and other elements. Equipment is available for measurements of soil water status as well as root and canopy growth. The experiments ran so far emphasize the diversity of the hosted research. Half of them concern global changes, often with a manipulation of more than one driver. About a quarter deal with the impact of biodiversity loss on ecosystem functioning and one quarter with ecosystem or plant physiology. We discuss how the methodology for environmental simulation and process measurements, especially in soil, can be improved and stress the need to establish stronger links with modelling in future projects. These developments will enable further improvements in mechanistic understanding and predictive capacity of ecotron research which will play, in complementarity with field experimentation and monitoring, a crucial role in exploring the ecosystem consequences of environmental changes.
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Resco de Dios V, Anderegg WR, Li X, Tissue DT, Bahn M, Landais D, Milcu A, Yao Y, Nolan RH, Roy J, Gessler A. Circadian Regulation Does Not Optimize Stomatal Behaviour. Plants (Basel) 2020; 9:E1091. [PMID: 32854373 PMCID: PMC7570086 DOI: 10.3390/plants9091091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/13/2020] [Accepted: 08/21/2020] [Indexed: 02/05/2023]
Abstract
The circadian clock is a molecular timer of metabolism that affects the diurnal pattern of stomatal conductance (gs), amongst other processes, in a broad array of plant species. The function of circadian gs regulation remains unknown and here, we test whether circadian regulation helps to optimize diurnal variations in stomatal conductance. We subjected bean (Phaseolus vulgaris) and cotton (Gossypium hirsutum) canopies to fixed, continuous environmental conditions of photosynthetically active radiation, temperature, and vapour pressure deficit (free-running conditions) over 48 h. We modelled gs variations in free-running conditions to test for two possible optimizations of stomatal behaviour under circadian regulation: (i) that stomata operate to maintain constant marginal water use efficiency; or (ii) that stomata maximize C net gain minus the costs or risks of hydraulic damage. We observed that both optimization models predicted gs poorly under free-running conditions, indicating that circadian regulation does not directly lead to stomatal optimization. We also demonstrate that failure to account for circadian variation in gs could potentially lead to biased parameter estimates during calibrations of stomatal models. More broadly, our results add to the emerging field of plant circadian ecology, where circadian controls may partially explain leaf-level patterns observed in the field.
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Affiliation(s)
- Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China;
- Department of Crop and Forest Sciences-AGROTECNIO Center, University of Lleida, 25198 Lleida, Spain
| | | | - Ximeng Li
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia; (X.L.); (D.T.T.); (R.H.N.)
| | - David T. Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia; (X.L.); (D.T.T.); (R.H.N.)
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, 6020 Innsbruck, Austria;
| | - Damien Landais
- Ecotron Européen de Montpellier, CNRS, 34980 Montferrier-sur-Lez, France; (D.L.); (A.M.); (J.R.)
| | - Alexandru Milcu
- Ecotron Européen de Montpellier, CNRS, 34980 Montferrier-sur-Lez, France; (D.L.); (A.M.); (J.R.)
- Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), CNRS, UMR 5175, Université de Montpellier, Université Paul Valéry, EPHE, IRD, 34293 Montpellier, France
| | - Yinan Yao
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China;
| | - Rachael H. Nolan
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia; (X.L.); (D.T.T.); (R.H.N.)
| | - Jacques Roy
- Ecotron Européen de Montpellier, CNRS, 34980 Montferrier-sur-Lez, France; (D.L.); (A.M.); (J.R.)
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland;
- Institute of Terrestrial Ecosystems, ETH Zurich, 8092 Zurich, Switzerland
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Volaire F, Morvan-Bertrand A, Prud’homme MP, Benot ML, Augusti A, Zwicke M, Roy J, Landais D, Picon-Cochard C. The resilience of perennial grasses under two climate scenarios is correlated with carbohydrate metabolism in meristems. J Exp Bot 2020; 71:370-385. [PMID: 31557303 PMCID: PMC6913708 DOI: 10.1093/jxb/erz424] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/10/2019] [Indexed: 05/30/2023]
Abstract
Extreme climatic events (ECEs) such as droughts and heat waves affect ecosystem functioning and species turnover. This study investigated the effect of elevated CO2 on species' resilience to ECEs. Monoliths of intact soil and their plant communities from an upland grassland were exposed to 2050 climate scenarios with or without an ECE under ambient (390 ppm) or elevated (520 ppm) CO2. Ecophysiological traits of two perennial grasses (Dactylis glomerata and Holcus lanatus) were measured before, during, and after ECE. At similar soil water content, leaf elongation was greater under elevated CO2 for both species. The resilience of D. glomerata increased under enhanced CO2 (+60%) whereas H. lanatus mostly died during ECE. D. glomerata accumulated 30% more fructans, which were more highly polymerized, and 4-fold less sucrose than H. lanatus. The fructan concentration in leaf meristems was significantly increased under elevated CO2. Their relative abundance changed during the ECE, resulting in a more polymerized assemblage in H. lanatus and a more depolymerized assemblage in D. glomerata. The ratio of low degree of polymerization fructans to sucrose in leaf meristems was the best predictor of resilience across species. This study underlines the role of carbohydrate metabolism and the species-dependent effect of elevated CO2 on the resilience of grasses to ECE.
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Affiliation(s)
| | | | | | - Marie-Lise Benot
- UCA, INRA, VetAgro Sup, UMR 874, Clermont-Ferrand, France
- INRA and Université de Bordeaux, UMR 1202 BIOGECO33610, Cestas, France
| | - Angela Augusti
- UCA, INRA, VetAgro Sup, UMR 874, Clermont-Ferrand, France
- CNR-Institute of Research on Terrestrial Ecosystems, Porano (TR), Italy
| | - Marine Zwicke
- UCA, INRA, VetAgro Sup, UMR 874, Clermont-Ferrand, France
| | - Jacques Roy
- CNRS, UPS 3248, Ecotron Européen de Montpellier, Montferrier-sur-Lez, France
| | - Damien Landais
- CNRS, UPS 3248, Ecotron Européen de Montpellier, Montferrier-sur-Lez, France
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Roscher C, Karlowsky S, Milcu A, Gessler A, Bachmann D, Jesch A, Lange M, Mellado-Vázquez P, Strecker T, Landais D, Ravel O, Buchmann N, Roy J, Gleixner G. Functional composition has stronger impact than species richness on carbon gain and allocation in experimental grasslands. PLoS One 2019; 14:e0204715. [PMID: 30703101 PMCID: PMC6354960 DOI: 10.1371/journal.pone.0204715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/07/2019] [Indexed: 11/18/2022] Open
Abstract
Numerous experiments have shown positive diversity effects on plant productivity, but little is known about related processes of carbon gain and allocation. We investigated these processes in a controlled environment (Montpellier European Ecotron) applying a continuous 13CO2 label for three weeks to 12 soil-vegetation monoliths originating from a grassland biodiversity experiment (Jena Experiment) and representing two diversity levels (4 and 16 sown species). Plant species richness did not affect community- and species-level 13C abundances neither in total biomass nor in non-structural carbohydrates (NSC). Community-level 13C excess tended to be higher in the 16-species than in the 4-species mixtures. Community-level 13C excess was positively related to canopy leaf nitrogen (N), i.e. leaf N per unit soil surface. At the species level, shoot 13C abundances varied among plant functional groups and were larger in legumes and tall herbs than in grasses and small herbs, and correlated positively with traits as leaf N concentrations, stomatal conductance and shoot height. The 13C abundances in NSC were larger in transport sugars (sucrose, raffinose-family oligosaccharides) than in free glucose, fructose and compounds of the storage pool (starch) suggesting that newly assimilated carbon is to a small portion allocated to storage. Our results emphasize that the functional composition of communities is key in explaining carbon assimilation in grasslands.
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Affiliation(s)
- Christiane Roscher
- Department of Physiological Diversity, UFZ, Helmholtz Centre for Environmental Research, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | | | - Alexandru Milcu
- Montpellier European Ecotron (UPS 3248), National Center for Scientific Research (CNRS), Montferrier sur-Lez, France
- Centre d’Ecologie Fonctionnelle et Evolutive (UMR 5175), CNRS, Université de Montpellier, Université Paul-Valéry, EPHE, IRD, Montpellier, France
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Zürich, Switzerland
| | - Dörte Bachmann
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Annette Jesch
- Department of Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Markus Lange
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | | | - Tanja Strecker
- J.F. Blumbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen, Germany
| | - Damien Landais
- Montpellier European Ecotron (UPS 3248), National Center for Scientific Research (CNRS), Montferrier sur-Lez, France
| | - Olivier Ravel
- Montpellier European Ecotron (UPS 3248), National Center for Scientific Research (CNRS), Montferrier sur-Lez, France
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Jacques Roy
- Montpellier European Ecotron (UPS 3248), National Center for Scientific Research (CNRS), Montferrier sur-Lez, France
| | - Gerd Gleixner
- Max Planck Institute for Biogeochemistry, Jena, Germany
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Guderle M, Bachmann D, Milcu A, Gockele A, Bechmann M, Fischer C, Roscher C, Landais D, Ravel O, Devidal S, Roy J, Gessler A, Buchmann N, Weigelt A, Hildebrandt A. Dynamic niche partitioning in root water uptake facilitates efficient water use in more diverse grassland plant communities. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12948] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marcus Guderle
- Friedrich‐Schiller‐University JenaInstitute of Geosciences Jena Germany
- Department of Ecology and Ecosystem ManagementTechnische Universität München Freising Germany
- Max Planck Institute for Biogeochemistry, Biogeochemical Processes Jena Germany
| | - Dörte Bachmann
- Institute of Agricultural SciencesETH Zurich Zurich Switzerland
| | - Alexandru Milcu
- CNRS, Ecotron ‐ UPS 3248 Montferrier‐sur‐Lez France
- Centre d'Ecologie Fonctionnelle et EvolutiveCEFE‐CNRSUMR 5175Université de Montpellier – Université Paul Valéry – EPHE Montpellier Cedex 5 France
| | - Annette Gockele
- Department of GeobotanyFaculty of BiologyUniversity of Freiburg Freiburg Germany
| | - Marcel Bechmann
- Friedrich‐Schiller‐University JenaInstitute of Geosciences Jena Germany
- Max Planck Institute for Biogeochemistry, Biogeochemical Processes Jena Germany
| | - Christine Fischer
- Friedrich‐Schiller‐University JenaInstitute of Geosciences Jena Germany
- Department of Conservation BiologyUFZHelmholtz Centre for Environmental Research Leipzig Germany
| | - Christiane Roscher
- Department of Physiological DiversityUFZHelmholtz Centre for Environmental Research Leipzig Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Leipzig Germany
| | | | | | | | - Jacques Roy
- CNRS, Ecotron ‐ UPS 3248 Montferrier‐sur‐Lez France
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL Birmensdorf Switzerland
- Berlin‐Brandenburg Institute of Advanced Biodiversity Research (BBIB) Berlin Germany
| | - Nina Buchmann
- Institute of Agricultural SciencesETH Zurich Zurich Switzerland
| | - Alexandra Weigelt
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Leipzig Germany
- Systematic Botany and Functional BiodiversityInstitute of BiologyUniversity of Leipzig Leipzig Germany
| | - Anke Hildebrandt
- Friedrich‐Schiller‐University JenaInstitute of Geosciences Jena Germany
- Max Planck Institute for Biogeochemistry, Biogeochemical Processes Jena Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Leipzig Germany
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García-Plazaola JI, Fernández-Marín B, Ferrio JP, Alday JG, Hoch G, Landais D, Milcu A, Tissue DT, Voltas J, Gessler A, Roy J, Resco de Dios V. Endogenous circadian rhythms in pigment composition induce changes in photochemical efficiency in plant canopies. Plant Cell Environ 2017; 40:1153-1162. [PMID: 28098350 DOI: 10.1111/pce.12909] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/03/2017] [Accepted: 01/04/2017] [Indexed: 05/16/2023]
Abstract
There is increasing evidence that the circadian clock is a significant driver of photosynthesis that becomes apparent when environmental cues are experimentally held constant. We studied whether the composition of photosynthetic pigments is under circadian regulation, and whether pigment oscillations lead to rhythmic changes in photochemical efficiency. To address these questions, we maintained canopies of bean and cotton, after an entrainment phase, under constant (light or darkness) conditions for 30-48 h. Photosynthesis and quantum yield peaked at subjective noon, and non-photochemical quenching peaked at night. These oscillations were not associated with parallel changes in carbohydrate content or xanthophyll cycle activity. We observed robust oscillations of Chl a/b during constant light in both species, and also under constant darkness in bean, peaking when it would have been night during the entrainment (subjective nights). These oscillations could be attributed to the synthesis and/or degradation of trimeric light-harvesting complex II (reflected by the rhythmic changes in Chl a/b), with the antenna size minimal at night and maximal around subjective noon. Considering together the oscillations of pigments and photochemistry, the observed pattern of changes is counterintuitive if we assume that the plant strategy is to avoid photodamage, but consistent with a strategy where non-stressed plants maximize photosynthesis.
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Affiliation(s)
| | - Beatriz Fernández-Marín
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
- Institute of Botany, University of Innsbruck, A6020, Innsbruck, Austria
| | - Juan Pedro Ferrio
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, 25198, Lleida, Spain
- Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Josu G Alday
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, 25198, Lleida, Spain
| | - Günter Hoch
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, 4056, Basel, Switzerland
| | - Damien Landais
- Ecotron Européen de Montpellier, CNRS, UPS-3248, Montferrier-sur-Lez, France
| | - Alexandru Milcu
- Ecotron Européen de Montpellier, CNRS, UPS-3248, Montferrier-sur-Lez, France
- Centre d'Ecologie Fonctionnelle et Evolutive, CEFE-CNRS, UMR-5175, Université de Montpellier - Université Paul Valéry - EPHE, 1919 route de Mende, F-34293, Montpellier Cedex 5, France
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, 2753, New South Wales, Australia
| | - Jordi Voltas
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, 25198, Lleida, Spain
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
- Institute for Landscape Biogeochemistry, Leibniz-Centre for Agricultural Landscape Research (ZALF), 15374, Müncheberg, Germany
| | - Jacques Roy
- Ecotron Européen de Montpellier, CNRS, UPS-3248, Montferrier-sur-Lez, France
| | - Víctor Resco de Dios
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, 25198, Lleida, Spain
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, 2753, New South Wales, Australia
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Resco de Dios V, Gessler A, Ferrio JP, Alday JG, Bahn M, Del Castillo J, Devidal S, García-Muñoz S, Kayler Z, Landais D, Martín-Gómez P, Milcu A, Piel C, Pirhofer-Walzl K, Ravel O, Salekin S, Tissue DT, Tjoelker MG, Voltas J, Roy J. Circadian rhythms have significant effects on leaf-to-canopy scale gas exchange under field conditions. Gigascience 2016; 5:43. [PMID: 27765071 PMCID: PMC5072338 DOI: 10.1186/s13742-016-0149-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/20/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Molecular clocks drive oscillations in leaf photosynthesis, stomatal conductance, and other cell and leaf-level processes over ~24 h under controlled laboratory conditions. The influence of such circadian regulation over whole-canopy fluxes remains uncertain; diurnal CO2 and H2O vapor flux dynamics in the field are currently interpreted as resulting almost exclusively from direct physiological responses to variations in light, temperature and other environmental factors. We tested whether circadian regulation would affect plant and canopy gas exchange at the Montpellier European Ecotron. Canopy and leaf-level fluxes were constantly monitored under field-like environmental conditions, and under constant environmental conditions (no variation in temperature, radiation, or other environmental cues). RESULTS We show direct experimental evidence at canopy scales of the circadian regulation of daytime gas exchange: 20-79 % of the daily variation range in CO2 and H2O fluxes occurred under circadian entrainment in canopies of an annual herb (bean) and of a perennial shrub (cotton). We also observed that considering circadian regulation improved performance by 8-17 % in commonly used stomatal conductance models. CONCLUSIONS Our results show that circadian controls affect diurnal CO2 and H2O flux patterns in entire canopies in field-like conditions, and its consideration significantly improves model performance. Circadian controls act as a 'memory' of the past conditions experienced by the plant, which synchronizes metabolism across entire plant canopies.
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Affiliation(s)
- Víctor Resco de Dios
- Department of Crop and Forest Sciences Agrotecnico Center, Universitat de Lleida, 25198, Lleida, Spain.
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research, Long-term Forest Ecosystem Research, 8903, Birmensdorf, Switzerland
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research, 15374, Müncheberg, Germany
| | - Juan Pedro Ferrio
- Department of Crop and Forest Sciences Agrotecnico Center, Universitat de Lleida, 25198, Lleida, Spain
- Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Josu G Alday
- Department of Crop and Forest Sciences Agrotecnico Center, Universitat de Lleida, 25198, Lleida, Spain
- School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, UK
| | - Michael Bahn
- Institute of Ecology, University of Innsbruck, 6020, Innsbruck, Austria
| | - Jorge Del Castillo
- Department of Crop and Forest Sciences Agrotecnico Center, Universitat de Lleida, 25198, Lleida, Spain
| | - Sébastien Devidal
- Ecotron Européen de Montpellier, UPS 3248, Centre National de la Recherche Scientifique, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
| | - Sonia García-Muñoz
- Instituto Madrileño de Investigación y Desarrollo Rural, Agrario y Alimentario, Finca 'El Encín', 28800, Alcalá de Henares, Madrid, Spain
| | - Zachary Kayler
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research, 15374, Müncheberg, Germany
- USDA Forest Service, Northern Research Station, Lawrence Livermore National Laboratory, Livermore, California, 94550, USA
| | - Damien Landais
- Ecotron Européen de Montpellier, UPS 3248, Centre National de la Recherche Scientifique, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
| | - Paula Martín-Gómez
- Department of Crop and Forest Sciences Agrotecnico Center, Universitat de Lleida, 25198, Lleida, Spain
| | - Alexandru Milcu
- Ecotron Européen de Montpellier, UPS 3248, Centre National de la Recherche Scientifique, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
- Centre National de la Recherche Scientifique, Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, Université de Montpellier, Université Paul Valéry, École Pratique des Hautes Études, F-34293, Montpellier Cedex 5, France
| | - Clément Piel
- Ecotron Européen de Montpellier, UPS 3248, Centre National de la Recherche Scientifique, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
| | - Karin Pirhofer-Walzl
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research, 15374, Müncheberg, Germany
- Institut für Biologie, Plant Ecology, Freie Universität Berlin, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Olivier Ravel
- Ecotron Européen de Montpellier, UPS 3248, Centre National de la Recherche Scientifique, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
| | - Serajis Salekin
- Erasmus Mundus Master on Mediterranean Forestry and Natural Resources Management, Universitat de Lleida, 25198, Lleida, Spain
- School of Forestry, College of Engineering, University of Canterbury, 8140, Christchurch, New Zealand
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Jordi Voltas
- Department of Crop and Forest Sciences Agrotecnico Center, Universitat de Lleida, 25198, Lleida, Spain
| | - Jacques Roy
- Ecotron Européen de Montpellier, UPS 3248, Centre National de la Recherche Scientifique, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
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Milcu A, Eugster W, Bachmann D, Guderle M, Roscher C, Gockele A, Landais D, Ravel O, Gessler A, Lange M, Ebeling A, Weisser WW, Roy J, Hildebrandt A, Buchmann N. Plant functional diversity increases grassland productivity-related water vapor fluxes: an Ecotron and modeling approach. Ecology 2016; 97:2044-2054. [DOI: 10.1890/15-1110.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 01/04/2016] [Accepted: 03/03/2016] [Indexed: 11/18/2022]
Affiliation(s)
- Alexandru Milcu
- CNRS; Ecotron (UPS-3248); Campus Baillarguet F-34980 Montferrier-sur-Lez France
- Centre d'Ecologie Fonctionnelle et Evolutive; CEFE-CNRS, UMR 5175; Université de Montpellier, Université Paul Valéry, EPHE; 1919 route de Mende F-34293 Montpellier Cedex 5 France
| | - Werner Eugster
- Institute of Agricultural Sciences; ETH Zurich; Universitaetsstrasse 2 8092 Zurich Switzerland
| | - Dörte Bachmann
- Institute of Agricultural Sciences; ETH Zurich; Universitaetsstrasse 2 8092 Zurich Switzerland
| | - Marcus Guderle
- Institute of Geoscience; Friedrich Schiller University Jena; Burgweg 11 07749 Jena Germany
| | - Christiane Roscher
- UFZ; Helmholtz Centre for Environmental Research; Department of Community Ecology; Theodor-Lieser-Strasse 4 06120 Halle Germany
| | - Annette Gockele
- Institut für Biologie II, Geobotanik; Albert-Ludwigs-Universität Freiburg; Schänzlestrasse 1 D-79104 Freiburg Germany
| | - Damien Landais
- CNRS; Ecotron (UPS-3248); Campus Baillarguet F-34980 Montferrier-sur-Lez France
| | - Olivier Ravel
- CNRS; Ecotron (UPS-3248); Campus Baillarguet F-34980 Montferrier-sur-Lez France
| | - Arthur Gessler
- Swiss Federal Research Institute WSL; Zürcherstrasse 111 8903 Birmensdorf Switzerland
| | - Markus Lange
- Max Planck Institute for Biogeochemistry; Hans-Knoell-Strasse 10 07745 Jena Germany
| | - Anne Ebeling
- Institute of Ecology; Friedrich Schiller University Jena; Dornburger Strasse 159 07743 Jena Germany
| | - Wolfgang W. Weisser
- Terrestrial Ecology Research Group; Department of Ecology and Ecosystem Management; School of Life Sciences Weihenstephan; Technische Universität München; Hans-Carl-von-Carlowitz-Platz 2 85354 Freising Germany
| | - Jacques Roy
- CNRS; Ecotron (UPS-3248); Campus Baillarguet F-34980 Montferrier-sur-Lez France
| | - Anke Hildebrandt
- Institute of Geoscience; Friedrich Schiller University Jena; Burgweg 11 07749 Jena Germany
| | - Nina Buchmann
- Institute of Agricultural Sciences; ETH Zurich; Universitaetsstrasse 2 8092 Zurich Switzerland
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Roy J, Picon-Cochard C, Augusti A, Benot ML, Thiery L, Darsonville O, Landais D, Piel C, Defossez M, Devidal S, Escape C, Ravel O, Fromin N, Volaire F, Milcu A, Bahn M, Soussana JF. Elevated CO2 maintains grassland net carbon uptake under a future heat and drought extreme. Proc Natl Acad Sci U S A 2016; 113:6224-9. [PMID: 27185934 PMCID: PMC4896684 DOI: 10.1073/pnas.1524527113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Extreme climatic events (ECEs) such as droughts and heat waves are predicted to increase in intensity and frequency and impact the terrestrial carbon balance. However, we lack direct experimental evidence of how the net carbon uptake of ecosystems is affected by ECEs under future elevated atmospheric CO2 concentrations (eCO2). Taking advantage of an advanced controlled environment facility for ecosystem research (Ecotron), we simulated eCO2 and extreme cooccurring heat and drought events as projected for the 2050s and analyzed their effects on the ecosystem-level carbon and water fluxes in a C3 grassland. Our results indicate that eCO2 not only slows down the decline of ecosystem carbon uptake during the ECE but also enhances its recovery after the ECE, as mediated by increases of root growth and plant nitrogen uptake induced by the ECE. These findings indicate that, in the predicted near future climate, eCO2 could mitigate the effects of extreme droughts and heat waves on ecosystem net carbon uptake.
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Affiliation(s)
- Jacques Roy
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France;
| | - Catherine Picon-Cochard
- Grassland Ecosystem Research, Unité de Recherche 874, Institut National de la Recherche Agronomique (INRA), F-63039 Clermont-Ferrand, France
| | - Angela Augusti
- Grassland Ecosystem Research, Unité de Recherche 874, Institut National de la Recherche Agronomique (INRA), F-63039 Clermont-Ferrand, France; Institute of Agroenvironmental and Forest Biology, Consiglio Nazionale delle Ricerche, 2-05010 Porano (TR), Italy
| | - Marie-Lise Benot
- Grassland Ecosystem Research, Unité de Recherche 874, Institut National de la Recherche Agronomique (INRA), F-63039 Clermont-Ferrand, France; Biodiversité Gènes et Communautés, INRA, Université de Bordeaux, F-33615 Pessac, France
| | - Lionel Thiery
- Grassland Ecosystem Research, Unité de Recherche 874, Institut National de la Recherche Agronomique (INRA), F-63039 Clermont-Ferrand, France
| | - Olivier Darsonville
- Grassland Ecosystem Research, Unité de Recherche 874, Institut National de la Recherche Agronomique (INRA), F-63039 Clermont-Ferrand, France
| | - Damien Landais
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France
| | - Clément Piel
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France
| | - Marc Defossez
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France
| | - Sébastien Devidal
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France
| | - Christophe Escape
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France
| | - Olivier Ravel
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France
| | - Nathalie Fromin
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, Unité Mixte de Recherche 5175, Université de Montpellier, Université Paul Valéry, École Pratique des Hautes Études, F-34293 Montpellier Cedex 5, France
| | - Florence Volaire
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, Unité Mixte de Recherche 5175, Université de Montpellier, Université Paul Valéry, École Pratique des Hautes Études, F-34293 Montpellier Cedex 5, France; Unité Sous Contrat 1338, INRA, Centre d'Ecologie Fonctionnelle et Evolutive F-34293 Montpellier Cedex 5, France
| | - Alexandru Milcu
- Ecotron Européen de Montpellier, Unité Propre de Service 3248, Centre National de la Recherche Scientifique (CNRS), Campus Baillarguet, F-34980 Montferrier-sur-Lez, France; Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, Unité Mixte de Recherche 5175, Université de Montpellier, Université Paul Valéry, École Pratique des Hautes Études, F-34293 Montpellier Cedex 5, France
| | - Michael Bahn
- Institute of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Jean-François Soussana
- Grassland Ecosystem Research, Unité de Recherche 874, Institut National de la Recherche Agronomique (INRA), F-63039 Clermont-Ferrand, France
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de Dios VR, Roy J, Ferrio JP, Alday JG, Landais D, Milcu A, Gessler A. Processes driving nocturnal transpiration and implications for estimating land evapotranspiration. Sci Rep 2015; 5:10975. [PMID: 26074373 PMCID: PMC4466595 DOI: 10.1038/srep10975] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/21/2015] [Indexed: 11/13/2022] Open
Abstract
Evapotranspiration is a major component of the water cycle, yet only daytime transpiration is currently considered in Earth system and agricultural sciences. This contrasts with physiological studies where 25% or more of water losses have been reported to occur occurring overnight at leaf and plant scales. This gap probably arose from limitations in techniques to measure nocturnal water fluxes at ecosystem scales, a gap we bridge here by using lysimeters under controlled environmental conditions. The magnitude of the nocturnal water losses (12-23% of daytime water losses) in row-crop monocultures of bean (annual herb) and cotton (woody shrub) would be globally an order of magnitude higher than documented responses of global evapotranspiration to climate change (51-98 vs. 7-8 mm yr(-1)). Contrary to daytime responses and to conventional wisdom, nocturnal transpiration was not affected by previous radiation loads or carbon uptake, and showed a temporal pattern independent of vapour pressure deficit or temperature, because of endogenous controls on stomatal conductance via circadian regulation. Our results have important implications from large-scale ecosystem modelling to crop production: homeostatic water losses justify simple empirical predictive functions, and circadian controls show a fine-tune control that minimizes water loss while potentially increasing posterior carbon uptake.
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Affiliation(s)
- Víctor Resco de Dios
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, 25198 Lleida, Spain
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | - Jacques Roy
- Ecotron Européen de Montpellier, UPS 3248, CNRS, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
| | - Juan Pedro Ferrio
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, 25198 Lleida, Spain
| | - Josu G. Alday
- School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, UK
| | - Damien Landais
- Ecotron Européen de Montpellier, UPS 3248, CNRS, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
| | - Alexandru Milcu
- Ecotron Européen de Montpellier, UPS 3248, CNRS, Campus Baillarguet, 34980, Montferrier-sur-Lez, France
- CNRS, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE, UMR-5175), 1919, route de Mende, 34293, Montpellier, France
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL Long-term Forest Ecosystem Research (LWF), 8903 Birmensdorf, Switzerland
- Institute for Landscape Biogeochemistry, Leibniz-Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
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11
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Milcu A, Roscher C, Gessler A, Bachmann D, Gockele A, Guderle M, Landais D, Piel C, Escape C, Devidal S, Ravel O, Buchmann N, Gleixner G, Hildebrandt A, Roy J. Functional diversity of leaf nitrogen concentrations drives grassland carbon fluxes. Ecol Lett 2014; 17:435-44. [DOI: 10.1111/ele.12243] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 11/08/2013] [Accepted: 12/10/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Alexandru Milcu
- CNRS, Ecotron - UPS 3248; Campus Baillarguet; 34980 Montferrier-sur-Lez France
| | - Christiane Roscher
- Department Community of Ecology; UFZ; Helmholtz Centre for Environmental Research; Theodor-Lieser-Str. 4 06120 Halle Germany
| | - Arthur Gessler
- Leibniz Centre for Agricultural Landscape Research (ZALF); Institute for Landscape Biogeochemistry; Eberswalderstr. 84 15374 Müncheberg Germany
| | - Dörte Bachmann
- Institute of Agricultural Sciences; ETH Zurich; Universitaetsstrasse 2 8092 Zurich Switzerland
| | - Annette Gockele
- Institut für Biologie II - Geobotanik; Albert-Ludwigs-Universität Freiburg; Schänzlestr. 1 D-79104 Freiburg Germany
| | - Markus Guderle
- Friedrich Schiller University Jena; Institute of Geoscience; Burgweg 11 07749 Jena Germany
| | - Damien Landais
- CNRS, Ecotron - UPS 3248; Campus Baillarguet; 34980 Montferrier-sur-Lez France
| | - Clément Piel
- CNRS, Ecotron - UPS 3248; Campus Baillarguet; 34980 Montferrier-sur-Lez France
| | - Christophe Escape
- CNRS, Ecotron - UPS 3248; Campus Baillarguet; 34980 Montferrier-sur-Lez France
| | - Sebastien Devidal
- CNRS, Ecotron - UPS 3248; Campus Baillarguet; 34980 Montferrier-sur-Lez France
| | - Olivier Ravel
- CNRS, Ecotron - UPS 3248; Campus Baillarguet; 34980 Montferrier-sur-Lez France
| | - Nina Buchmann
- Institute of Agricultural Sciences; ETH Zurich; Universitaetsstrasse 2 8092 Zurich Switzerland
| | - Gerd Gleixner
- Max Planck Institute for Biogeochemistry; POB 100164 07701 Jena Germany
| | - Anke Hildebrandt
- Friedrich Schiller University Jena; Institute of Geoscience; Burgweg 11 07749 Jena Germany
| | - Jacques Roy
- CNRS, Ecotron - UPS 3248; Campus Baillarguet; 34980 Montferrier-sur-Lez France
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12
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Ross M, Camacho LH, Hersh EM, Brown CK, Richards J, Mitsky P, Wasserman E, Lee S, Bercovici N, Landais D, Ribas A. Clinical and Immunological responses in patients with malignant melanoma treated with a dendritic cell-based vaccine. Preliminary report from a multi-institutional phase II clinical trial. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.3004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
3004 Background: We have previously reported that vaccination with IDM therapeutic vaccine (IDD-3/Uvidem [Uvidem is co-developed with SANOFI-AVENTIS]) composed of dendritic cells (DC) loaded with three allogeneic lysates from tumor cell lines can elicit immune and anti-tumor responses. We describe here the preliminary results from a phase II clinical trial in metastatic melanoma patients. Methods: DC-MEL-202 is a single arm, two-stage phase II trial designed to evaluate clinical and immunological activities and the safety of a multivalent DC vaccine in patients with in-transit or low volume metastatic melanoma. There was no HLA restriction. Autologous DC were generated, under GMP conditions, from monocytes cultured in GM-CSF and IL-13, loaded with three allogeneic melanoma tumor lysates (M44, SK-MEL 28 and COLO 829) and matured with a combination of bacterial extract (FMKP) and IFN-γ, generating up to 15 doses of the vaccine containing 25x106 DC. Patients received six bi-weekly and two 6-weekly injections (id and sc). Clinical responders were eligible to receive additional doses. Immune response against tumor-associated antigens (TAA) peptides was assessed, at several time points, by detection of IFN-γ producing cells by flow cytometry Results: 33 patients were treated. To date: Vaccination is well tolerated with toxicity limited to mild events (only one possibly related SAE, age-related macular degeneration, was reported). Clinical response (RECIST): 6 patients showed evidence of clinical benefit (1CR, 1PR and 4 SD) with duration of response ranging from 7.5 to 22 months. Assessment of pathological response in target sites in 2 pts (1 PR, 1 SD) showed no residual disease.. 23/33 patients are still alive with a mean follow-up of 11mo (range 3–22mo). Mature data of PFS and OS will be presented. Immune response: 21 (84 %) out of 25 evaluated patients showed detectable TAA-specific CD8+ T cells with ten showing boosted or appearance of anti-TAA specific CD8+ T cells. Conclusions: Vaccination with IDD-3/Uvidem is safe and can elicit tumor specific CD8+ T cells not limited to HLA-A2+ patients. Substantial clinical benefit warrants further development of IDD3. No significant financial relationships to disclose.
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Affiliation(s)
- M. Ross
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - L. H. Camacho
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - E. M. Hersh
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - C. K. Brown
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - J. Richards
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - P. Mitsky
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - E. Wasserman
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - S. Lee
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - N. Bercovici
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - D. Landais
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
| | - A. Ribas
- MD Anderson Cancer Center, Houston, TX; Arizona Cancer Center, Tuscon, AZ; University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA; Lutheran General Cancer Care Center, Park Ridge, IL; Paragon Biomedical, Inc., Claremont, CA; AAI Oncology, San Antonio, TX; IDM, Inc., Irvine, CA; IDM, SA., Paris, France; UCLA, Los Angeles, CA
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Staudt M, Mir C, Joffre R, Rambal S, Bonin A, Landais D, Lumaret R. Isoprenoid emissions of Quercus spp. (Q. suber and Q. ilex) in mixed stands contrasting in interspecific genetic introgression. New Phytol 2004; 163:573-584. [PMID: 33873752 DOI: 10.1111/j.1469-8137.2004.01140.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
• Among oak species, Quercus ilex is classified as a monoterpene emitter and Q. suber is mainly known as a nonisoprenoid emitter. The extent and origin of this diversification is unknown. • We examined intra- and interspecific emission variability in two mixed stands which differed in their level of hybridization and reciprocal genetic introgression based on variations in cytoplasmic (chloroplast DNA) and nuclear (allozyme) markers. • At both sites all trees identified as Q. ilex, or as recent descendants from Q. ilex × Q. suber hybrids, emitted monoterpenes. Of Q. suber trees (genetically introgressed or not by Q. ilex), 91% were also monoterpene emitters, and the remainder nonemitters. One tree identified as a Q. canariensis × Q. ilex hybrid emitted both isoprene and monoterpenes. Compared with Q. ilex, the standard emission rate of Q. suber was higher in summer and lower in autumn. Both species emitted the same monoterpenes, proportions of which showed significant intra- and interspecific variability. • The results suggest that Q. suber populations in the French Mediterranean intrinsically emit monoterpenes, and that gene flow between oak species contributes to diversification of emission signatures.
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Affiliation(s)
- Michael Staudt
- CNRS Centre d'Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Céline Mir
- CNRS Centre d'Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Richard Joffre
- CNRS Centre d'Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Serge Rambal
- CNRS Centre d'Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Aurélie Bonin
- CNRS Centre d'Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Damien Landais
- CNRS Centre d'Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Roselyne Lumaret
- CNRS Centre d'Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier cedex 5, France
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14
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Conseiller E, Debussche L, Landais D, Venot C, Maratrat M, Sierra V, Tocque B, Bracco L. CTS1: a p53-derived chimeric tumor suppressor gene with enhanced in vitro apoptotic properties. J Clin Invest 1998; 101:120-7. [PMID: 9421473 PMCID: PMC508547 DOI: 10.1172/jci1140] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The clinical potential of the p53 tumor suppressor gene is being evaluated currently for gene therapy of cancer. We have built a variant of wild-type p53, chimeric tumor suppressor 1 (CTS1), in which we have replaced the domains that mediate its inactivation. CTS1 presents some very interesting properties: (a) enhanced transcriptional activity; (b) resistance to the inactivation by oncogenic forms of p53; (c) resistance to the inactivation by MDM2; (d) lower sensitivity to E6-induced degradation; (e) ability to suppress cell growth; and (f ) faster induction of apoptosis. Thus, CTS1 is an improved tumor suppressor and an alternative for the treatment of wild-type p53-resistant human tumors by gene therapy.
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Affiliation(s)
- E Conseiller
- Gene Medicine Department, Rhône-Poulenc Rorer SA, 94403 Vitry sur Seine Cedex, France
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15
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Barlat I, Schweighoffer F, Chevallier-Multon MC, Duchesne M, Fath I, Landais D, Jacquet M, Tocque B. The Saccharomyces cerevisiae gene product SDC25 C-domain functions as an oncoprotein in NIH3T3 cells. Oncogene 1993; 8:215-8. [PMID: 7999142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Ras proteins in mammalian cells cycle between a GTP-bound 'on' state and a GDP-bound 'off' state. Activation of Ras p21 results from the dissociation of tightly bound GDP and the exchange of bound GDP for GTP. A guanine nucleotide exchange factor is required for this activation. Activation promotes interaction with effector molecules and allows the signal to be transduced. In Saccharomyces cerevisiae, the function of guanine nucleotide exchange has been ascribed to the product of the CDC25 gene. The C-terminus domain of SDC25, a homologue of CDC25, can substitute for the CDC25 protein in yeast. We have demonstrated that the SDC25 C-terminus domain promotes GTP binding to Ras p21 in CHO cells. In the present study, we found that the stable expression of the SDC25 C-terminus domain induced transformation of NIH3T3 cells. Ras proteins in these tumorigenic cells were GTP bound. In addition, the coexpression of wild-type Ha-Ras protein with the SDC25 C-terminus was found to enhance the tumorigenic properties of the NIH3T3 cells. These results imply that, in subsets of human tumours, cellular Ras p21 might be found in its GTP-bound active form as a consequence of an oncogenic activation of a mammalian Ras guanine nucleotide exchange factor.
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Affiliation(s)
- I Barlat
- Rhone Poulence Rorer, Vitry sur Seine, France
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16
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Yeh P, Landais D, Lemaître M, Maury I, Crenne JY, Becquart J, Murry-Brelier A, Boucher F, Montay G, Fleer R. Design of yeast-secreted albumin derivatives for human therapy: biological and antiviral properties of a serum albumin-CD4 genetic conjugate. Proc Natl Acad Sci U S A 1992; 89:1904-8. [PMID: 1542690 PMCID: PMC48562 DOI: 10.1073/pnas.89.5.1904] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Due to its remarkably long half-life, together with its wide in vivo distribution and its lack of enzymatic or immunological functions, human serum albumin (HSA) represents an optimal carrier for therapeutic peptides/proteins aimed at interacting with cellular or molecular components of the vascular and interstitial compartments. As an example, we designed a genetically engineered HSA-CD4 hybrid aimed at specifically blocking the entry of the human immunodeficiency virus into CD4+ cells. In contrast with CD4, HSA-CD4 is correctly processed and efficiently secreted by Kluyveromyces yeasts. In addition, its CD4 moiety exhibits binding and antiviral in vitro properties similar to those of soluble CD4. Finally, the elimination half-life of HSA-CD4 in a rabbit experimental model is comparable to that of control HSA and 140-fold higher than that of soluble CD4. These results indicate that the genetic fusion of bioactive peptides to HSA is a plausible approach toward the design and recovery of secreted therapeutic HSA derivatives with appropriate pharmacokinetic properties.
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Affiliation(s)
- P Yeh
- Rhône-Poulenc Rorer, Centre de Recherche de Vitry-Alfortville, Vitry, France
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Rosloniec EF, Vitez LJ, Beck BN, Buerstedde J, McKean DJ, Landais D, Benoist C, Mathis D, Freed JH. I-Ak polymorphisms define a functionally dominant region for the presentation of hen egg lysozyme peptides. The Journal of Immunology 1989. [DOI: 10.4049/jimmunol.143.9.3104.a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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18
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Reske-Kunz AB, Landais D, Peccoud J, Benoist C, Mathis D. Functional sites on the A alpha-chain. Polymorphic residues involved in antigen presentation to insulin-specific, Ab alpha:Ak beta-restricted T cells. The Journal of Immunology 1989. [DOI: 10.4049/jimmunol.143.5.1472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The interaction between the clonally selected TCR, the processed Ag peptide and the Ia molecule is not fully understood in molecular terms. Our study intended to delineate the residues of Ab alpha molecules that function as contact sites for Ag and for the TCR of a panel of T cells specific for the A chain of insulin in combination with mixed haplotype Ab alpha:Ak beta molecules. Multiple L cell transfectants expressing alpha,beta-heterodimers composed of wild-type A beta- and chimeric or mutant A alpha-chains served as antigen presenting cells. The recombinant A alpha-chains had been generated by an exchange of allelically hypervariable regions (ahv) or amino acids. The results point out a broad spectrum of b sequence requirements for the bovine insulin-specific activation of the various T cell populations. Activation of some T cells seemed quite permissive, requiring b-haplotype amino acids in any one of the three ahv, while others had strict requirements, demanding b-haplotype sequence in all three ahv. Our data stress the role of ahvII and especially ahvIII in T cell activation. Interestingly, single amino-acid substitutions in ahvII or ahvIII of Ak alpha were sufficient to bring up full stimulation potential for two T cell hybridomas. We also found that some ahv permutations influenced the Ag preference (beef insulin versus pig insulin) of some T cells. These data suggest a critical role for the three-dimensional structure of the complex formed by Ia and the processed Ag peptide. The stability of the trimolecular complex essential for T cell activation is envisioned as being the sum of the interactions between Ag/I-A, TCR/Ag, and TCR/I-A, each variable in strength and compensated for by the others.
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Affiliation(s)
- A B Reske-Kunz
- Institut für Immunologie, Johannes Gutenberg-Universität, Mainz, FRG
| | - D Landais
- Institut für Immunologie, Johannes Gutenberg-Universität, Mainz, FRG
| | - J Peccoud
- Institut für Immunologie, Johannes Gutenberg-Universität, Mainz, FRG
| | - C Benoist
- Institut für Immunologie, Johannes Gutenberg-Universität, Mainz, FRG
| | - D Mathis
- Institut für Immunologie, Johannes Gutenberg-Universität, Mainz, FRG
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19
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Reske-Kunz AB, Landais D, Peccoud J, Benoist C, Mathis D. Functional sites on the A alpha-chain. Polymorphic residues involved in antigen presentation to insulin-specific, Ab alpha:Ak beta-restricted T cells. J Immunol 1989; 143:1472-81. [PMID: 2474599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The interaction between the clonally selected TCR, the processed Ag peptide and the Ia molecule is not fully understood in molecular terms. Our study intended to delineate the residues of Ab alpha molecules that function as contact sites for Ag and for the TCR of a panel of T cells specific for the A chain of insulin in combination with mixed haplotype Ab alpha:Ak beta molecules. Multiple L cell transfectants expressing alpha,beta-heterodimers composed of wild-type A beta- and chimeric or mutant A alpha-chains served as antigen presenting cells. The recombinant A alpha-chains had been generated by an exchange of allelically hypervariable regions (ahv) or amino acids. The results point out a broad spectrum of b sequence requirements for the bovine insulin-specific activation of the various T cell populations. Activation of some T cells seemed quite permissive, requiring b-haplotype amino acids in any one of the three ahv, while others had strict requirements, demanding b-haplotype sequence in all three ahv. Our data stress the role of ahvII and especially ahvIII in T cell activation. Interestingly, single amino-acid substitutions in ahvII or ahvIII of Ak alpha were sufficient to bring up full stimulation potential for two T cell hybridomas. We also found that some ahv permutations influenced the Ag preference (beef insulin versus pig insulin) of some T cells. These data suggest a critical role for the three-dimensional structure of the complex formed by Ia and the processed Ag peptide. The stability of the trimolecular complex essential for T cell activation is envisioned as being the sum of the interactions between Ag/I-A, TCR/Ag, and TCR/I-A, each variable in strength and compensated for by the others.
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Affiliation(s)
- A B Reske-Kunz
- Institut für Immunologie, Johannes Gutenberg-Universität, Mainz, FRG
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20
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Rosloniec EF, Vitez LJ, Beck BN, Buerstedde JM, McKean DJ, Landais D, Benoist C, Mathis D, Freed JH. I-Ak polymorphisms define a functionally dominant region for the presentation of hen egg lysozyme peptides. J Immunol 1989; 143:50-8. [PMID: 2786533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The class II molecules of the MHC not only bind processed antigenic peptides but also interact with the TCR. This latter interaction is thought to be the basis for allele specific "restriction" of Ag presentation to T cells. The specificity of this interaction is likely due to amino acid differences in a small number of polymorphic or "hypervariable" regions located in the amino terminal domains of the alpha- and beta-chains. We have explored the functional significance of these polymorphic regions in an I-Ak-restricted, hen egg lysozyme specific Ag presentation system in which the measurement of IL-2 production by T cell hybridomas was used as the indicator of TCR recognition of the I-A/Ag complex. Chimeric I-A molecules, in which b allelic residues were substituted in one or more of the polymorphic regions of the A alpha k chain or in which d allelic residues were substituted in one or more of the polymorphic regions of the A beta k chain, were used to examine the contribution of each polymorphic region of the molecule to its function. The results obtained demonstrate that the regions between residues 69 to 76 of the A alpha k chain and the regions between residues 63 to 67 and 75 to 78 of the A beta k-chain exert a dominant effect on the presentation of lysozyme peptides by I-Ak to the T cell hybridomas in our panel. These observations were confirmed and extended by the analysis of Ag presentation by seven serologically selected mutants, all of which have amino acid interchanges in or around the dominant polymorphic regions. The results suggest that the serologically selected mutants fail to present Ag not because they fail to bind the peptide Ag but because the amino acid substitutions destabilize the interaction between the Ia/peptide complex and the TCR. Use of the recently published hypothetical model for class II structure to interpret the Ag presentation results suggests that the dominant polymorphic regions lie across from one another near one end of the alpha-helices that form the two walls of the proposed Ag-binding cleft located on the top surface of the class II molecule. Furthermore, the majority of the amino acids which have been changed in the serologically selected mutants have side chains which are postulated to point up toward the exterior of the molecule and would, therefore, be potential contact residues for the TCR.
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Affiliation(s)
- E F Rosloniec
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
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21
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Rosloniec EF, Vitez LJ, Beck BN, Buerstedde JM, McKean DJ, Landais D, Benoist C, Mathis D, Freed JH. I-Ak polymorphisms define a functionally dominant region for the presentation of hen egg lysozyme peptides. The Journal of Immunology 1989. [DOI: 10.4049/jimmunol.143.1.50] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The class II molecules of the MHC not only bind processed antigenic peptides but also interact with the TCR. This latter interaction is thought to be the basis for allele specific "restriction" of Ag presentation to T cells. The specificity of this interaction is likely due to amino acid differences in a small number of polymorphic or "hypervariable" regions located in the amino terminal domains of the alpha- and beta-chains. We have explored the functional significance of these polymorphic regions in an I-Ak-restricted, hen egg lysozyme specific Ag presentation system in which the measurement of IL-2 production by T cell hybridomas was used as the indicator of TCR recognition of the I-A/Ag complex. Chimeric I-A molecules, in which b allelic residues were substituted in one or more of the polymorphic regions of the A alpha k chain or in which d allelic residues were substituted in one or more of the polymorphic regions of the A beta k chain, were used to examine the contribution of each polymorphic region of the molecule to its function. The results obtained demonstrate that the regions between residues 69 to 76 of the A alpha k chain and the regions between residues 63 to 67 and 75 to 78 of the A beta k-chain exert a dominant effect on the presentation of lysozyme peptides by I-Ak to the T cell hybridomas in our panel. These observations were confirmed and extended by the analysis of Ag presentation by seven serologically selected mutants, all of which have amino acid interchanges in or around the dominant polymorphic regions. The results suggest that the serologically selected mutants fail to present Ag not because they fail to bind the peptide Ag but because the amino acid substitutions destabilize the interaction between the Ia/peptide complex and the TCR. Use of the recently published hypothetical model for class II structure to interpret the Ag presentation results suggests that the dominant polymorphic regions lie across from one another near one end of the alpha-helices that form the two walls of the proposed Ag-binding cleft located on the top surface of the class II molecule. Furthermore, the majority of the amino acids which have been changed in the serologically selected mutants have side chains which are postulated to point up toward the exterior of the molecule and would, therefore, be potential contact residues for the TCR.
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Affiliation(s)
- E F Rosloniec
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - L J Vitez
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - B N Beck
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - J M Buerstedde
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - D J McKean
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - D Landais
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - C Benoist
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - D Mathis
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | - J H Freed
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
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Pierres M, Marchetto S, Naquet P, Landais D, Peccoud J, Benoist C, Mathis D. I-A alpha polymorphic residues that determine alloreactive T cell recognition. J Exp Med 1989; 169:1655-68. [PMID: 2469763 PMCID: PMC2189303 DOI: 10.1084/jem.169.5.1655] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
An individual's T lymphocytes are highly reactive to allogeneic MHC molecules. As a step in deciphering the mechanism of allorecognition by T lymphocytes, we have attempted to identify the TCR's target on MHC class II molecules, in particular the polymorphic residues that determine the specificity of recognition. We have generated a panel of Ak-reactive, Ab-nonreactive T cell hybridomas, and sets of L cell transfectants displaying A alpha A beta molecules with wild-type, chimeric or single site-mutated A alpha chains, with reciprocal interchanges between Ak and Ab. We then measured the stimulation of the T hybridomas in response to the transfectants. The results indicate that the hybridomas recognize diverse and complex determinants, with contributions from both A alpha and A beta chains, and from several regions or amino acids of the A alpha chain. The data are most consistent with a model in which alloreactivity results from the presentation of peptides to the T cell by an allogeneic MHC molecule, peptides that cannot be presented by the responder's own MHC complexes. The specificity of allorecognition seems to be imparted mainly by peptide/MHC molecule rather than TCR/MHC molecule contacts.
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Affiliation(s)
- M Pierres
- Centre d'Immunologie Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique de Marseille-Luminy, France
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23
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Landais D, Marchetto S, Waltzinger C, Pierres M, Benoist C, Mathis D. Slot-machine mutagenesis of a polymorphic residue on the A kappa alpha-chain. The Journal of Immunology 1988. [DOI: 10.4049/jimmunol.141.2.667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
This study explores the limitations on variability at a polymorphic position of an MHC class II molecule. Using a convenient and rapid method termed "slot-machine mutagenesis," we have converted Glu75 on the A kappa-chain to 15 alternative amino acids. This residue is of interest because it is an immunodominant site on the A kappa alpha chain and because it participates in certain T cell epitopes. The wild-type and mutant A kappa alpha cDNA were transfected into L cells (together with the A kappa beta cDNA and a selection marker), and transfectants displaying high surface levels of the A kappa complex were selected and expanded. We sought to examine three questions: what is the effect of these mutations on the expression and overall conformation of the A alpha: A beta complex? How do these diverse mutations influence mAb epitopes for which Glu75 makes a direct contribution to specificity? Do such substitutions affect T cell recognition of the A kappa alpha:A kappa beta complex? The answers to these three questions are quite different. Position 75 of the A alpha chain can accommodate essentially all chemically divergent amino acids without major consequences for expression and overall A alpha:A beta structure. In contrast, mAb that recognize Glu75-dependent epitopes are extremely particular about the amino acid residing at this position. T cells are less fastidious: those that are affected by the mutations still recognize a number of substitutions. These data emphasize the tolerance of MHC molecules to evolutionary tampering.
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Affiliation(s)
- D Landais
- Laboratoire de Génétique Moléculaire des Eucaryotes, CNRS, Strasbourg, France
| | - S Marchetto
- Laboratoire de Génétique Moléculaire des Eucaryotes, CNRS, Strasbourg, France
| | - C Waltzinger
- Laboratoire de Génétique Moléculaire des Eucaryotes, CNRS, Strasbourg, France
| | - M Pierres
- Laboratoire de Génétique Moléculaire des Eucaryotes, CNRS, Strasbourg, France
| | - C Benoist
- Laboratoire de Génétique Moléculaire des Eucaryotes, CNRS, Strasbourg, France
| | - D Mathis
- Laboratoire de Génétique Moléculaire des Eucaryotes, CNRS, Strasbourg, France
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Landais D, Marchetto S, Waltzinger C, Pierres M, Benoist C, Mathis D. Slot-machine mutagenesis of a polymorphic residue on the A kappa alpha-chain. J Immunol 1988; 141:667-71. [PMID: 2898505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This study explores the limitations on variability at a polymorphic position of an MHC class II molecule. Using a convenient and rapid method termed "slot-machine mutagenesis," we have converted Glu75 on the A kappa-chain to 15 alternative amino acids. This residue is of interest because it is an immunodominant site on the A kappa alpha chain and because it participates in certain T cell epitopes. The wild-type and mutant A kappa alpha cDNA were transfected into L cells (together with the A kappa beta cDNA and a selection marker), and transfectants displaying high surface levels of the A kappa complex were selected and expanded. We sought to examine three questions: what is the effect of these mutations on the expression and overall conformation of the A alpha: A beta complex? How do these diverse mutations influence mAb epitopes for which Glu75 makes a direct contribution to specificity? Do such substitutions affect T cell recognition of the A kappa alpha:A kappa beta complex? The answers to these three questions are quite different. Position 75 of the A alpha chain can accommodate essentially all chemically divergent amino acids without major consequences for expression and overall A alpha:A beta structure. In contrast, mAb that recognize Glu75-dependent epitopes are extremely particular about the amino acid residing at this position. T cells are less fastidious: those that are affected by the mutations still recognize a number of substitutions. These data emphasize the tolerance of MHC molecules to evolutionary tampering.
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Affiliation(s)
- D Landais
- Laboratoire de Génétique Moléculaire des Eucaryotes, CNRS, Strasbourg, France
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Landais D, Waltzinger C, Beck BN, Staub A, McKean DJ, Benoist C, Mathis D. Functional sites on Ia molecules: a molecular dissection of A alpha immunogenicity. Cell 1986; 47:173-81. [PMID: 2429774 DOI: 10.1016/0092-8674(86)90440-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ia antigens are polymorphic cell-surface molecules that control the immune response. We have begun to localize important functional sites on one of the Ia molecules, A alpha. Herein, we focus on the A alpha k and A alpha b alleles and ask what defines "b-ness" and "k-ness" for a panel of monoclonal antibodies. Two independent experimental strategies are employed: the ability of 12 monoclonal antibodies to recognize L cell transfectants bearing chimeric and mutant A alpha chains is assessed, and the amino acid sequences of A alpha chains expressed by immunoselected B lymphoma mutants are deduced. For each antibody, we identify a stretch of polymorphic residues critical for recognition; for several, we can pinpoint a single amino acid. Certain stretches of A alpha (depending on the allele) appear strikingly immunodominant.
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Abstract
The murine Ia antigens, heterodimeric glycoproteins on the surface of immunocompetent cells, restrict immune recognition by their influence on cell-cell interactions. Many serological specificities have been mapped to these molecules, and monoclonal antibodies directed against some of these determinants block antigen presentation to T lymphocytes. As a step toward a better understanding of Ia function, we sought to define the molecular basis of Ia.2 and Ia.19, specificities found on the A alpha chain of only the k or of both k and r haplotypes, respectively. We report nucleotide sequences for the A alpha chain cDNAs of the k, r, and s haplotypes, which, when compared to previously published A alpha sequences, demonstrate the existence of one k-specific amino acid residue and of another present only in the k and r haplotypes. These residues must thus play an important role in the generation of Ia.2 and Ia.19 specificities.
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