Thèses sur le sujet « Fixation biologique de l'azote »
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Daveran, Marie-Line. « Structure et transcription des genes de fixation de l'azote de rhizobium meliloti ». Toulouse 3, 1988. http://www.theses.fr/1988TOU30001.
Texte intégralBringuier, Charline. « Effet des changements climatiques et atmosphériques sur la croissance et la fixation biologique de l'azote chez Anabaena variabilis : importance des disponibilités du molybdène et du phosphore ». Mémoire, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8790.
Texte intégralAveline, Anne. « Etude de la variabilité de la fixation biologique de l'azote : impacts sur le rendement du soja (Glycine max L.) cultivé en zone tempéré et en zone tropicale ». Lyon 1, 1995. http://www.theses.fr/1995LYO10008.
Texte intégralRiano, Sanchez Jaime Andres. « Evolution of the global productivity of terrestrial ecosystems under constraint linked to nitrogen availability : analysis over the recent historical period and future projections ». Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASJ012.
Texte intégralTerrestrial ecosystems currently absorb more than a quarter of CO₂ emissions of anthropogenic origin, thanks to the fertilization effect associated with the increase in atmospheric CO₂. Most of the terrestrial system models used in recent IPCC work estimate that terrestrial ecosystems will continue to behave like a carbon sink of greater or lesser magnitude in the 21st century, depending on the future trajectories of atmospheric CO₂ and climate. Whatever the evolution of atmospheric CO₂ concentration, it remains critical to determining whether enough nutrients (particularly nitrogen) will be available to fully support the increase in primary production resulting from the fertilization effect of elevated CO₂. Most global models of terrestrial ecosystems do not account for the nitrogen cycle and the interactions between the nitrogen and carbon cycles. The latest version of the ORCHIDEE model developed in France incorporates these new features.Using this model, the objective of the thesis will be to analyze the evolution of terrestrial productivity over the recent historical period and to quantify the future development of the productivity of terrestrial ecosystems under the combined effect of these global changes: climate, CO₂ concentration, and reactive nitrogen production evolution, according to different socio-economic scenarios. Including the coupled nitrogen and carbon cycle in ORCHIDEE also requires a better approximation to one key Nitrogen input resulting from Biological Nitrogen Fixation that is currently determined by evapotranspiration. This has been recently invalidated by a meta analysis study. The second objective of this thesis consists then of implementing a process-based dynamic model for reproducing BNF in ORCHIDEE to improve the estimation of the carbon fluxes
Guinet, Maé. « Quantification des flux d’azote induits par les cultures de légumineuses et étude de leurs déterminants : comparaison de 10 espèces de légumineuses à graines ». Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCK011/document.
Texte intégralIn the context of agroecological transition, the reintroduction of legume crops should play a key role in cropping system sustainability by allowing a reduction of nitrogen (N) inputs. But few references are available concerning the agronomical and ecological services provided by a wide range of legume crops, particularly within crops succession scale. Thus, the main objective of our study is to quantify the N fluxes during and after the legume crops taking into account 10 legume crops (peas, lupin, faba bean, soybean...). Our experiment consists in i) quantifying symbiotic N fixation depending on the amount of soil inorganic N, the mineralisation of N present in legume crop residues after soil incorporation and N losses outside of the soil-plant system (leaching, emission of nitrous oxide), ii) identifying plant biological traits associated to N fluxes. Thus, different N fluxes were quantified during a two-year field experiment, i.e. the first year (2014) legume crops were implanted and followed by wheat the second year (14-15) after incorportation of legume residues. This experiment was repeated in 2016-2017.In parallel, plant root traits were characterised during greenhouse hydroponic experiments
Norel, Françoise. « Génétique de la fixation de l'azote chez Rhizobium ORS571 ». Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37600048c.
Texte intégralKush, Anil Kumar. « Etude biochimique et génétique de la fixation de l'azote chez Rhizobium ORS57l ». Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37598814w.
Texte intégralDaveran, Marie-Line. « Structure et transcription des gènes de fixation de l'azote de Rhizobium meliloti ». Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612936j.
Texte intégralSOUILLARD, NICOLE. « Clonage, structure primaire et expression de genes nif (fixation de l'azote) d'archaebacteries methanogenes ». Paris 6, 1989. http://www.theses.fr/1989PA066469.
Texte intégralNna, Mvondo Delphine. « Fixation atmosphérique de l'azote par les décharges électriques durant l'histoire de la Terre ». Paris 12, 2002. http://www.theses.fr/2002PA120068.
Texte intégralOn Earth, nitrogen can be used by living organisms only if it is "fixed", that is to say if it is present in reactive forms, as ammonia, nitrates, nitrogen oxides or nitrogen chemically tied up to organic molecules. Nitrogen can be fixed biologically or abiotically by industrial processes and by lightning diseharges during thunderstonns. On early Earth, lightning could have been one of the most important sources of fixed nitrogen needed for die emergence of life supplying about 10 [puissance]12 g NO per year. In this work, we report the first experimental simulation of atmospheric nitrogen fixation by electric diseharges, including lightning and corona diseharges, during ail geologic history of die Earth, from an atmosphere predominantly composed of carbon dioxide in die Hadean and Archean to the current oxygenic atmosphere dominated by dinitrogen. This experimental study consists of simulating in laboratory the Earth' s atmosphere from neutral (CO2 - N2) to oxygenic (O2 - N2), of subjecting these gaseous mixtures to irradiation that mimic thunderstorm lightning and corona point-discharges, then of analyzing the nitrogen products by GC-MS-IRTF and also only by infrared spectroscopy. In order to explain the observed variations in the energy yields of NO, NO2 and N2O for each atmosphere and each discharge, we propose chemical mechanisms of formation of these three compounds. The estimates of their annual productions for lightning and corona processes in terrestrial simulated atmospheres allow us to constrain the contribution of electric processes in the abiotic nitrogen fixation, and to examine if the evolution of the atmosphere could have influenced the production of reactive nitrogen available for the living organisms
Bouzouklian, Hervé. « Le Gène glnA d'Azospirillum brasilense propriétés et ralation avec la fixation de l'azote ». Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37596401z.
Texte intégralSchwoob, Cathie. « Les développements récents de la chimie de complexation de l'azote ». Strasbourg 1, 1985. http://www.theses.fr/1985STR10536.
Texte intégralMICHEL, REYDELLET NATHALIE. « Regulation de la fixation de l'azote et de l'assimilation de l'ammoniaque chez azorhizobium caulinodans ». Paris 6, 1998. http://www.theses.fr/1998PA066238.
Texte intégralDron, Anthony. « Activités nycthémérales de la cyanobactérie fixatrice d'azote Crocosphaera watsonii : réponses face au photopériodisme ». Paris 6, 2012. http://www.theses.fr/2012PA066577.
Texte intégralCrocosphaera watsonii is a unicellular, N2-fixing cyanobacterium, which is abundant in the euphotic layer of the tropical and subtropical oceans (from 40 °N to 30 °S), where it contributes substantially to the primary production. Due to the O2-sensitivity of the nitrogenase, the latter occurs during the dark period, when the oxygen-evolving photosynthesis can not process. These two antagonistic activities constrain to a tight circadian orchestration (periode of 24h) of the physiological activities. The aim of this thesis is the investigate the effect of the photoperiodism (different length of the photoperiod) on the carbon-nitrogen metabolism and the progression of the cell cycle. For that, we performed some continuous cultures experiments with C. Watsonii, subjected to different light conditions. This innovative approach in C. Watsonii showed that this environmental factor had significant consequences on the somatic growth (biomass production) and on the cell division (production of new cells). A short photoperiod length promotes the somatic growth instead of the cell division. Beyond the simple explanation of the physiological processes, our results highlighted that C. Watsonii could provide to its environment large amount of new nitrogen and carbohydrate-rich organic composed as well. This important excretion of compound, for most organic, emphasizes the ecological importance of this organism in the oceanic areas, generally oligotrophic
Boëns, Benjamin. « Synthèse et évaluation biologique de moutardes à l'azote à motifs pyrimidiques, puriques et triazoliques ». Limoges, 2012. https://aurore.unilim.fr/theses/nxfile/default/62bf6d8a-876a-4afd-b44b-b4edd3d4e2a6/blobholder:0/2012LIMO4054.pdf.
Texte intégralThe synthesis of pyrimidine, purine and triazole nitrogen mustards is described. First, we studied the synthesis of uracil-based nitrogen mustards. The amidation step was particularly studied and this method was extended to several amines. A series of DFT calculations highlighted the significance of non-bounding interactions in this amidation step. Second, the synthesis of several purine-based nitrogen mustards is described. This synthetic pathway led to the formation of tricyclic compounds, derive from purine. In a third part, we were interested in the elaboration of a new family of triazole nitrogen mustards. Thanks to the use of CuAAC reaction, we managed to synthesize 8 new nitrogen mustards. This latter strategy paves the way to the synthesis of a new family of nitrogen mustards, with an important structural variability. Furthermore, we studied the biological activity of synthesized compounds by testing their cytotoxicity and, then, by flow cytometry. Two of them showed encouraging results towards four cancer cells lines
Lavire, Céline. « Modulation des propriétés symbiotiques de Frankia : mécanismes de régulation génétique et métabolisme de l'azote ». Lyon 1, 2002. http://www.theses.fr/2002LYO10081.
Texte intégralBurias, Nicole. « Amélioration de la fixation symbiotique de l'azote et productivité chez le soja (Glycine max. (L. ) Merrill) ». Toulouse, INPT, 1991. http://www.theses.fr/1991INPT011A.
Texte intégralLe, Grand Nathalie. « Contribution à l'étude des processus de transfert de couples {H+/e} et de transformation de ligands en relation avec la réduction de l'azote moléculaire ». Brest, 2001. http://www.theses.fr/2001BRES2007.
Texte intégralHouyou, Nassima. « Suivi isotopique par RMN et GC-MS de l'assimilation de l'azote chez les plantules de colza : Aspects de régulation de la nitrate réductase ». Amiens, 2006. http://www.theses.fr/2006AMIE0627.
Texte intégralIn rapeseed (Brassica napus) seedlings, ammonium as the sole nitrogen source induces a twofold increase in nitrate reductase (NR) activity (NRA) in shoots comprising the cotyledons and hypocotyls (Leleu, 2000) instead of the usual decrease. We have studied the involved metabolic pathways to shed light on this unusual mechanism of NR regulation. Thus, the 15N isotope exploration of nitrogen assimilation pathways with in vivo NMR, in vitro NMR and GC-MS was optimised, and then used to study the metabolic response of NR in rapeseed shoots towards the kind of nitrogen source (ammonium NH4Cl or nitrate KNO3), the presence or the absence of light and the effect of GS/GOGAT inhibitors. Our results indicate a stimulation of 15NO3 - assimilation fluxes after exposure of rapeseed plantlets to ammonium as compared to nitrate exposure. This stimulation was found to be related to the synthesis of large quantities of glutamine by the GS/GOGAT cycle under ammonium exposure. Use of the GS inhibitor MSX and the GOGAT inhibitor azaserine revealed an effect of the glutamine level on the in vivo NR activity which is consistent with in vitro measurements under the same physiological conditions (Leleu, 2000). Finally, the twofold activation of the 15NO3 - assimilation flux by light was observed under both nitrate and ammonium conditions. This light activation seems to be independent from the ammonium activation and thus from the effect of glutamine indicating two separate mechanisms of NR regulation
Djekoune, Abdelhamid. « Photosynthèse, fixation symbiotique de l'azote et résistance à la sécheresse chez le soja (Glycine max. L. Merril) ». Toulouse, INPT, 1990. http://www.theses.fr/1990INPT001A.
Texte intégralDELORME, FREDERIC. « Etude de la regulation de la fixation de l'azote et du metabolisme azote chez azospirillum brasilense sp7 ». Paris 7, 1991. http://www.theses.fr/1991PA077028.
Texte intégralZgani, Ibrahim. « Synthèse et évaluation biologique de nouveaux analogues de pyrophosphates de prényles ». Montpellier 2, 2001. http://www.theses.fr/2001MON20077.
Texte intégralPhilip, Pascale de. « Etude de la protéine FixL de Rhizobium meliloti impliquée dans la régulation de l'expression des gènes de fixation symbiotique de l'azote ». Toulouse 3, 1992. http://www.theses.fr/1992TOU30275.
Texte intégralBernier, Jean. « Modélisation du comportement de l'azote dans un système de traitement individuel d'épuration ». Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27487/27487.pdf.
Texte intégralSchiltz, Séverine. « Caractérisation du processus de remobilisation de l'azote des organes végétatifs pendant le remplissage des graines chez Pisum sativum L. Par marquages isotopiques et protéomique ». Dijon, 2006. http://www.theses.fr/2006DIJOS012.
Texte intégralThe mechanism of nitrogen remobilisations from vegetative organs to filling seeds was characterised by isotopic nitrogen labelling and proteomic. From these analyses, organs from which nitrogen is remobilised were identified, their contribution to seed nitrogen yield were quantified, the nature of remobilised nitrogen pools were determined and the metabolic pathways that were involved were pointed out. Then, the genotypic variability was studied in eight pea genotypes contrasted for morphological traits and seed nitrogen content. This study showed that nitrogen remobilised from vegetative organs was the main nitrogen source for filling seeds. Remobilised N constituted a unique nitrogen pool that was redistributed between seeds independently from their position on the plant and so their developmental stage whatever the genotype. Proteins and mainly, photosynthetic proteins were the main nitrogen pool remobilised from leaves and stems
Bourgues, Sophie. « Ecologie des bactéries sulfato-réductrices en milieu lagunaire : minéralisation de la matière organique et fixation de l'azote atmosphérique ». Bordeaux 1, 1996. http://www.theses.fr/1996BOR10630.
Texte intégralSoussana, Jean-François. « Fixation symbiotique de l'azote et assimilation du nitrate chez la luzerne (Medicago sativa L. ) : aspects méthodologiques, aspects physiologiques ». Montpellier 2, 1986. http://www.theses.fr/1986MON20048.
Texte intégralSoussana, Jean-François. « Fixation symbiotique de l'azote et assimilation du nitrate chez la Luzerne (Medicago sativa L.) aspects méthodologiques, aspects physiologiques / ». Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb376013473.
Texte intégralLeiris, Simon. « Synthèse et évaluation biologique des nouvelles moutardes à l'azote ciblant les mitochondries ou les lysosomes des cellules cancéreuses ». Montpellier 2, 2006. http://www.theses.fr/2006MON20009.
Texte intégralBerthelot, Hugo. « Fixation d'azote et son devenir dans l'océan de surface : transfert dans le réseau trophique planctonique et influence sur les cycles biogéochimiques de l'azote et du carbone ». Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4103/document.
Texte intégralThis PhD thesis, achieved within the framework of the VAHINE project, focuses on the fate of the recently fixed N2 by diazotrophes in the oligotrophic surface ocean.It appears that the release of the recently fixed N2 in the dissolved pool is a process shared between all diazotrophs tested and that the magnitude of this release depend on the environmental contrains rather than on diazotroph involved in fixation.The transfer of the N2 fixed toward non-diazotroph plankton has been investigated using an innovative methodology (coupling of nano-scale mass spectrometry (nanoSIMS) and cell sorting flow cytometry). It appeared that 5 to 20 % of the recently fixed N2 is transferred toward non-diazotroph plankton, mainly through NH4+ release. This transfer is twice more efficient when the N2 is fixed by the filamentous Trichodesmium compared to Crocosphaera and Cyanothece.Particulate export of the fixed N2 has been investigate in large in-situ mesocosms equipped with sediment traps, deployed in the New Caledonian lagoon and enriched with PO43- in order to stimulate N2 fixation. During this experiment, N2 fixation fueled a large part of the new primary production (>90 %) and that fixed N2 was quickly exported. The export has been direct, through the sedimentation of the diazotrophs themselves, and indirect, through the transfer of ~20 % of the recently fixed N2 toward non-diazotrophic plankton that have, in turn, sedimented
Guénin-Tabary, Florence. « Caractérisation moléculaire de la lectine de riz et étude de sa liaison a certaines bactéries fixant l'azote ». Paris 7, 1985. http://www.theses.fr/1985PA077047.
Texte intégralFOUSSARD, MARIE. « La regulation negative des genes de fixation de l'azote chez sinorhizobium meliloti : mise en evidence d'un nouveau regulateur, fixt ». Toulouse 3, 1998. http://www.theses.fr/1998TOU30184.
Texte intégralFabre, Françoise. « Amélioration génétique de la qualité de la graine et fixation symbiotique de l'azote chez le soja (Glycine max L. ) ». Toulouse, INPT, 1998. http://www.theses.fr/1998INPT015A.
Texte intégralEl, Halouani Hassan. « Lagunage à haut rendement : caractérisation physico-chimique de l'écosystème, étude de son aptitude à l'élimination de l'azote et du phosphore dans l'épuration des eaux usées ». Montpellier 1, 1990. http://www.theses.fr/1990MON13511.
Texte intégralCosseau, Céline. « Régulation par AICAR/5'AMP de l'expression des gènes de fixation de l'azote sous la dépendance du système FixLJ chez Sinorhizobium meliloti ». Toulouse 3, 2002. http://www.theses.fr/2002TOU30053.
Texte intégralLemaire, Romain. « Etudes fondamentales et développement de procédés innovants pour l'élimination biologique de l'azote et du phosphore dans des effluents d'abattoir ». Montpellier 2, 2007. http://www.theses.fr/2007MON20090.
Texte intégralThe meat processing industry requires large quantities of water, much of which is discharged as wastewater containing high levels of COD and nutrients such as nitrogen (N) and phosphorus (P). These nutrients must be removed to very low levels before the wastewater can be discharged into local waterways to avoid causing eutrophication. The aim of this thesis was to develop a biological process that could achieve more than 95% of COD, N and P removal from abattoir wastewater, producing an effluent suitable for direct discharge into river systems. The main challenge is to achieve stable and reliable biological P removal in nitrogen-rich wastewater. A sequencing batch reactor (SBR) system was demonstrated to effectively remove 95%, 97% and 98% of the total COD, total N and total P present in abattoir wastewater. It could provide a more cost-effective and environmentally friendly alternative to chemical P removal, which is the common practice in the meat industry at present. A multi-step feeding strategy was employed to prevent the accumulation of nitrate or nitrite in the SBR providing the right condition for the development of a stable biological P removal. An automatic aeration length control strategy was developed and demonstrated to remove N via the nitrite pathway which benefited the nutrient removal performance of the SBR by reducing the amount of readily biodegradable COD required. This study also investigated the feasibility of using two innovative technologies to further enhance the performance of the SBR system. The simultaneous nitrification, denitrification and phosphorus removal (SNDPR) process and the aerobic granular sludge technology were successfully combined in a single SBR process. The size and the dense structure of aerobic granules positively contributed to the oxygen mass transfer limitation required to achieve reliable SNDPR. The structure and function of these granules fed with nutrient-rich wastewater were closely investigated using a wide range of microbial and micro-scale techniques, which yielded insightful information about aerobic granules and provided support for future in-depth studies on the mechanisms involved in aerobic biogranulation
Dion, Pierre-Paul, et Pierre-Paul Dion. « Minéralisation et prélèvement direct de l'azote organique dans les cultures légumières biologiques en serre ». Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/37893.
Texte intégralDevant la complexité du cycle de l’azote (N) et la variété de ses formes disponibles dans le sol, la planification de la fertilisation de cet élément repose sur des calculs et considérations complexes. La fertilisation biologique a de particulier que l’N est apporté sous forme organique, alors que les plantes le prélèvent principalement sous forme minérale. La disponibilité de l’N repose donc sur une minéralisation efficace des amendements. Cette situation peut mener des producteurs à surfertiliser, entraînant des pertes financières et d’N dans l’environnement. Parvenir à une meilleure synchronisation de la minéralisation de l’N avec les besoins de la plante est donc crucial pour le développement de la serriculture biologique, où les besoins en azote des cultures sont de loin plus élevés qu’au champ. De plus, la capacité de certaines plantes à prélever directement l’N sous forme organique est souvent considérée négligeable en agriculture, mais pourrait être plus importante qu’on ne le croit, contribuant ainsi substantiellement au bilan d’N de la plante. Les objectifs généraux de ma thèse étaient de : (1) évaluer les taux de minéralisation de fertilisants biologiques couramment utilisés en culture légumière sous serre au Québec ; (2) étudier l’impact de différentes sources fertilisantes sur la biodiversité des bactéries du sol ; (3) étudier la capacité du concombre à prélever l’N directement sous forme organique ; et (4) développer et valider un outil de gestion de la fertilisation biologique azotée. Une expérience d’incubation de cinq fertilisants biologiques d’usage commun en serriculture biologique a été menée. La minéralisation de l’N a plafonné dans un sol minéral et un substrat tourbeux à, respectivement, 41 et 63 % de l’N appliqué pour le fumier de poule granulé, 56-93 % pour la farine de sang, 54-81 % pour la farine de plume, 34-43 % pour la farine de luzerne et 57-73 % pour la farine de crevette. Dans un sol minéral, la biodiversité bactérienne alpha (indice Shannon) a été augmentée par l’apport de farine de luzerne, alors que dans un substrat organique à base de tourbe, ce sont la farine de crevette et le fumier de poule granulé qui l’ont le plus augmentée. En se basant sur ces résultats, le modèle NLOS a été adapté à la serriculture biologique pour produire le nouveau modèle NLOS-OG. Cet outil a été validé en serres expérimentales et commerciales et a permis une prédiction satisfaisante de la disponibilité d’N minéral pour une culture en sol minéral, ainsi que de la minéralisation cumulative de fertilisants appliqués dans un sol ou un substrat tourbeux. Par contre, de la recherche spécifique à la dynamique de l’eau dans les cultures biologiques en contenants sera nécessaire afin de prédire adéquatement la disponibilité de l’azote dans ce système. Une interface web est disponible pour les agronomes et producteurs (https://exchange.iseesystems. com/public/pierrepauldion/nlos-og/). Le contenu en C et N solubles du substrat biologique d’une culture de concombre en serre biologique a été positivement corrélé au contenu en C et N organiques de la sève du xylème et aux solides solubles du fruit, suggérant un prélèvement et un transfert de C et N organiques vers les parties aériennes et les fruits. Dans une seconde expérience, en milieu contrôlé, de jeunes plants de concombre ont été exposés à une solution d’alanine enrichie en 13C et 15N. En combinant l’utilisation de molécules marquées à une position spécifique (Position-specific labelling) et l’analyse isotopique spécifique au composé (Compound-specific isotopic analysis), nous avons développé une approche innovatrice permettant de suivre le métabolisme de l’assimilation de l’N issu d’un acide aminé prélevé par les racines. Nous avons ainsi démontré que les racines peuvent prélever et assimiler l’N sous forme organique, surtout en situation de rareté de l’N. Elles ont toutefois une nette préférence pour les formes inorganiques (nitrate et ammonium). Les contributions scientifiques découlant de cette étude doctorale sont : (1) une meilleure connaissance de la minéralisation des fertilisants biologiques azotés ; (2) l’intégration de ces taux de minéralisation dans un outil de gestion de l’N applicable en serriculture biologique; et (3) une meilleure compréhension du prélèvement et de l’assimilation de l’azote organique par des plants de concombre. Ces connaissances permettront une meilleure planification de la fertilisation à base de matière organique, et par conséquent un accroissement de la durabilité de la serriculture biologique.
Because of the complexity of the nitrogen (N) cycle and the diversity of its molecule forms in the soil, N fertilization management is based on complex calculations and considerations. For organic farming, N is provided via organic amendments and biological fixation. However, lack of precise tools that predict the N mineralization rate of N sources leads some producers to over-fertilize, resulting in the buildup of salinity, N leaching and possible loss of profits. Consequently, better knowledge of N availability following organic fertilization, to improve synchronization of N supply with crop N demand, is crucial to advance sustainable organic horticulture. In addition, the capacity of plants to take up N directly as organic molecules is seldom considered in agriculture and could be higher than previously thought, contributing significantly to the plant’s N budget. The objectives of this thesis were to: (1) evaluate the mineralization rates from organic fertilizers commonly used in greenhouse vegetable horticulture in Quebec; (2) study the impact of different fertilizer sources on soil bacterial diversity; (3) study the capacity of cucumber plants to take up and assimilate N directly as organic molecules; and (4) develop and validate a N management tool for organic fertilization. An incubation experiment with five organic fertilizers commonly used in organic greenhouse horticulture was performed. Nitrogen mineralization plateaued for a mineral soil and a peat substrate at respectively 41 and 63% of applied N for pelleted poultry manure, 56-93% for blood meal, 54-81% for feather meal, 34-53% for alfalfa meal, and 57-73% for shrimp meal. Organic fertilizers supported markedly contrasted bacterial communities, closely linked to soil biochemical properties, especially mineral N, pH and soluble C. Alfalfa meal promoted the highest alpha diversity (Shannon index) in the mineral soil, whereas shrimp meal and pelleted poultry manure increased it in the peat-based growing medium. Based on those results, we adapted the NLOS model to organic greenhouse horticulture and developed the new model NLOS-OG. This tool was validated in commercial and experimental greenhouses. It yielded a satisfying prediction of mineral N availability in a greenhouse crop grown in native mineral soil, and for the cumulative mineralization of fertilizers applied in a soil or organic substrate. However, further research should focus on water dynamics in containerized organic crops in order to achieve a precise prediction of N availability in that cropping system. A free web interface for NLOS-OG is now available for agronomists and growers (https://exchange. iseesystems.com/public/pierrepauldion/nlos-og/).In a greenhouse experiment, the C and N content of soil solution was positively linked to the xylem sap C and N content of mature cucumber plants and appeared to contribute to the accumulation of soluble solids in cucumber fruits, suggesting uptake and transfer of soil soluble organic N and C to the shoot and fruits. In a second experiment, in a growth chamber, young cucumber plants were exposed to 13C- and 15N-labelled alanine. By combining two methods, i.e., the use of Position-specific labelling (PSL) of alanine and Compound-specific isotopic analysis (CSIA) of free amino acids, we developed a novel approach allowing the study of the mechanism of the assimilatory metabolism of an amino acid taken up by the roots. We demonstrated that their roots can take up and assimilate N as organic molecules, although they showed a preference for inorganic N forms (nitrate and ammonium). The scientific contributions from this doctoral study are: (1) a better knowledge of the nitrogen release from nitrogen organic fertilizers; (2) the integration of mineralization rates into a N management tool adapted to organic greenhouse horticulture; and (3) a better understanding of the uptake and assimilation of organic N by cucumber plants. This knowledge will contribute to a better planning of N fertilization based on organic matter, thus increasing the sustainability of organic greenhouse horticulture.
Because of the complexity of the nitrogen (N) cycle and the diversity of its molecule forms in the soil, N fertilization management is based on complex calculations and considerations. For organic farming, N is provided via organic amendments and biological fixation. However, lack of precise tools that predict the N mineralization rate of N sources leads some producers to over-fertilize, resulting in the buildup of salinity, N leaching and possible loss of profits. Consequently, better knowledge of N availability following organic fertilization, to improve synchronization of N supply with crop N demand, is crucial to advance sustainable organic horticulture. In addition, the capacity of plants to take up N directly as organic molecules is seldom considered in agriculture and could be higher than previously thought, contributing significantly to the plant’s N budget. The objectives of this thesis were to: (1) evaluate the mineralization rates from organic fertilizers commonly used in greenhouse vegetable horticulture in Quebec; (2) study the impact of different fertilizer sources on soil bacterial diversity; (3) study the capacity of cucumber plants to take up and assimilate N directly as organic molecules; and (4) develop and validate a N management tool for organic fertilization. An incubation experiment with five organic fertilizers commonly used in organic greenhouse horticulture was performed. Nitrogen mineralization plateaued for a mineral soil and a peat substrate at respectively 41 and 63% of applied N for pelleted poultry manure, 56-93% for blood meal, 54-81% for feather meal, 34-53% for alfalfa meal, and 57-73% for shrimp meal. Organic fertilizers supported markedly contrasted bacterial communities, closely linked to soil biochemical properties, especially mineral N, pH and soluble C. Alfalfa meal promoted the highest alpha diversity (Shannon index) in the mineral soil, whereas shrimp meal and pelleted poultry manure increased it in the peat-based growing medium. Based on those results, we adapted the NLOS model to organic greenhouse horticulture and developed the new model NLOS-OG. This tool was validated in commercial and experimental greenhouses. It yielded a satisfying prediction of mineral N availability in a greenhouse crop grown in native mineral soil, and for the cumulative mineralization of fertilizers applied in a soil or organic substrate. However, further research should focus on water dynamics in containerized organic crops in order to achieve a precise prediction of N availability in that cropping system. A free web interface for NLOS-OG is now available for agronomists and growers (https://exchange. iseesystems.com/public/pierrepauldion/nlos-og/).In a greenhouse experiment, the C and N content of soil solution was positively linked to the xylem sap C and N content of mature cucumber plants and appeared to contribute to the accumulation of soluble solids in cucumber fruits, suggesting uptake and transfer of soil soluble organic N and C to the shoot and fruits. In a second experiment, in a growth chamber, young cucumber plants were exposed to 13C- and 15N-labelled alanine. By combining two methods, i.e., the use of Position-specific labelling (PSL) of alanine and Compound-specific isotopic analysis (CSIA) of free amino acids, we developed a novel approach allowing the study of the mechanism of the assimilatory metabolism of an amino acid taken up by the roots. We demonstrated that their roots can take up and assimilate N as organic molecules, although they showed a preference for inorganic N forms (nitrate and ammonium). The scientific contributions from this doctoral study are: (1) a better knowledge of the nitrogen release from nitrogen organic fertilizers; (2) the integration of mineralization rates into a N management tool adapted to organic greenhouse horticulture; and (3) a better understanding of the uptake and assimilation of organic N by cucumber plants. This knowledge will contribute to a better planning of N fertilization based on organic matter, thus increasing the sustainability of organic greenhouse horticulture.
Derlon, Nicolas. « Analyse de la compétition microbienne entre bactéries autolotrophes et hétérotrophes au sein d'un biofilm éliminant l'azote ». Toulouse, INSA, 2008. http://eprint.insa-toulouse.fr/archive/00000285/.
Texte intégralBiofim reactors are used in wastewater treatment for simultaneous COD and nitrogen removal. This biological process is based on a complex bacterial consortium, composed of both autotrophic and heterotrophic bacteria, associated in “biofilm”. The coexistence of these populations results of a microbial competition for both the substrates and the space. This microbial competition potentially leads to process failures as decreases of the removal rates, and thus its mechanisms must be understood. In this way, the objectives of this work were: (i) to develop a model of biofilm growth, (ii) to characterize the detachment mode and its impact on the competition, (iii) and to analyze the impact of the environmental growth conditions on the competition. The main results of this work are the following : a 1-D biofilm model, since the structure allows predicting population dynamics and the biofilm reactor performances, was developed. This is a multi-species and multi-substrates model, which assumes a continuous surface detachment. An experimental study of the detachment mode was performed. Different biofilms were grown under different various and contrasted growth conditions in Couette-Taylor Reactors. Erosion process was defined as a continuous surface detachment of small particles coupled with dynamic volume events detaching large particles. Using the model, different detachment modes in terms of fraction of biofilm thickness detached and in terms of frequency were tested. The dynamic volume events determine the heterotrophic growth at the biofilm surface, and thus the availability of oxygen inside the biofilm. If oxygen is limiting in the inner zone of the biofilm, the autotrophic growth is limited or impossible. By impacting the oxygen availability, the dynamic volume events consequently govern the result of the autotrophic-heterotrophic competition. Under oxygen-limiting conditions, the comparison between numerical and experimental results shows that a simple 1-D model overpredicts the advantage of the heterotrophic growth. The impact of more complex processes on autotrophic-heterotrophic coexistence was thus evaluated. Specific heterotrophic detachment and particulate convection were shown to favour the autotrophic growth and thus the autotrophic-heterotrophic coexistence. Finally, 1-D models considering simple biological and physical processes leads to a strict stratification of the functionalities. The following question is highlighted by this work: Is the strict stratification of the microbial functionalities predicted by simple 1-D model can potentially change the result of the autotrophic-heterotrophic competition ?
Josserand, Véronique. « Evaluation biologique de nouveaux radioligands iodés proposés comme marqueurs sélectifs des récepteurs ß1-adrénergiques myocardiques utilisables in vivo ». Université Joseph Fourier (Grenoble), 2002. http://www.theses.fr/2002GRE19003.
Texte intégralAndrianarison, Tahina Razanadraibe. « Traitement d'effluents urbains dans un système de 11 lagunes : décontamination microbienne et élimination de l'azote ». Montpellier 2, 2006. http://www.theses.fr/2006MON20104.
Texte intégralLebret, Nelly. « L'ammoniac biologique et ses dérivés : analyse et limitation dans la vie domestique ». Toulouse, INPT, 1992. http://www.theses.fr/1992INPT043G.
Texte intégralTirichine, Delacour Leïla. « Étude de la spécificité d'hôte pour la nodulation et la fixation de l'azote dans la symbiose Sinorhizobium-Medicago truncatula : identification de nouveaux gènes ». Toulouse, INPT, 2000. http://www.theses.fr/2000INPT005A.
Texte intégralBobik, Christine. « Génomique de la fixation de l’azote chez Sinorhizobium meliloti : analyse du régulon FixLJ ». Toulouse 3, 2006. http://www.theses.fr/2006TOU30149.
Texte intégralTransition of Sinorhizobium meliloti from free-living to symbiotic life is associated with an irreversible differentiation into nitrogen fixing bacteroïds. An original transcriptomic approach allowed us to identify new gene candidates to study successive stages of differentiation. Thus, we found about a hundred genes preferentially expressed during late symbiotic stages, among them nif and fix genes essential to nitrogen fixation and regulated by the FixLJ two-component system. We identified and characterised the FixJ regulon and showed that FixJ is a main regulator of both symbiotic and free-living microoxic conditions. FixJ is involved in various biological functions. Among new FixJ targets we found one which is essential to symbiosis
Hameed, Hassan Rasheed. « Transformation et translocation de l'azote sous influence lombricienne et microbienne : modèles et validation écologiques ». Montpellier 2, 1989. http://www.theses.fr/1989MON20243.
Texte intégralSoupène, Eric. « Régulation symbiotique de l'expression de gènes impliqués dans la fixation de l'azote lors de l'interaction Rhizobium meliloti-Medicago sativa : rôle de l'oxygène ». Toulouse 3, 1996. http://www.theses.fr/1996TOU30079.
Texte intégralLuna, Reyes. « Amélioration de la fixation symbiotique de l'azote chez le soja (Glycine max L. Merrill) : aptitudes de la souche SMGS1 de Bradyrhizobium japonicum ». Toulouse, INPT, 1995. http://www.theses.fr/1995INPT015A.
Texte intégralReyrat, Jean-Marc. « Regulation par l'oxygene de l'expression des genes de fixation symbiotique de l'azote de rhizobium meliloti : role du systeme a deux composants fixlj ». Paris 7, 1993. http://www.theses.fr/1993PA077297.
Texte intégralRahman, Shamsun Noor. « Etude de la fixation de l'azote par le trèfle blanc (Trifolium repens L.) effets du stress hydrique et de l'apport de potassium / ». Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37609139v.
Texte intégralDarbouret, Daniel. « Détection immunochimique d'une substance dans un fluide biologique : utilisation de particules calibrées permettant la fixation de molécules biologiquement actives ». Lyon 1, 1990. http://www.theses.fr/1990LYO10244.
Texte intégralFilali, Ahlem. « Analyse et modélisation du traitement de l'azote dans un procédé de granulation aérobie hydride ». Thesis, Toulouse, INSA, 2011. http://www.theses.fr/2011ISAT0037/document.
Texte intégralIn this work, the treatment of nutrients, especially that of nitrogen in aerobic granulation process was studied.The experimental approach has initially been intended to compare the stability and the physical and microbiological characteristics of aggregates developed in two reactors operating in alternating anaerobic / aerobic or anoxic / aerobic conditions. The presence of a pre-anoxic phase promoted the stabilization of nitrogen removal performances and especially those of nitrification. The development of a hybrid sludge process containing a fraction of flocs and granules was observed.In order to evaluate and quantify the influence of the simultaneous presence of flocs and granules in the nitrifying activity of the hybrid sludge developed in the alternating anoxic / aerobic conditions, the nitrification rate and oxygen limitation of flocs, granules and hybrid sludge was assessed using respirometric assays at different dissolved oxygen concentrations. The spatial distribution of nitrifying bacteria was investigated using fluorescence in situ hybridization (FISH). Results indicated that the presence of flocs with granules could increase the rate of nitrification to transitory reductions of aeration. On the other hand, the optimization of nitrogen removal requires the simultaneous control of the floc to granule ratio and granule size.Finally, a mathematical model to describe the reaction phenomena taking place in the hybrid biomass was developed. It was used in order to optimize the operation of the hybrid process through the evaluation of the effect of physical properties of biomass, specifically the ratio of granules and flocs in the reactor that can lead to efficient removal of nitrogen and increase the robustness of the process