Dissertations / Theses on the topic 'Adaptation du métabolisme'
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Le, Moullac Gilles. "Adaptation du métabolisme respiratoire de l'huître creuse Crassostrea gigas." Caen, 2008. http://www.theses.fr/2008CAEN2019.
Summer mortality of the oyster result from the interaction of many factors. A respiratory assumption proposes a link between the supposed causes of the energy state, the cultivation methods and the medium. This work is focused towards the search for specific metabolic markers of environmental stresses. The cDNA of genes coding for PK and PEPCK were cloned and sequenced in order to detect their regulation level. The sediment nearness affects the state of energy reserves, the metabolic pathways of energy production implying a regulation of the PK. Face to the dissolved oxygen decline, oysters were oxyregulator but with a low regulation ability. In hypoxia, glycolysis was slowed down. PK activity was inhibited resulting from an increase in alanine sensitivity whereas ETS activity of the respiratory chain was stimulated. When exposed to sulphides, filtration of oyster was affected from 20µM whereas the oxygen consumption persisted. At short term, an anaerobic metabolic pathway associated to the inhibition of the respiratory chain and the fall of CEA took place. Muscular PK and PEPCK had different regulation levels: PEPCK appeared controlled at the transcriptional level and PK was first allosterically regulated before to be lately regulated at transcriptional level. Lastly, this study revealed new specificities of the oysters R and S. In normoxia, the more important stock of carbohydrate of the S oysters was correlated to a higher production of ATP via a more intense PK activity. In hypoxia, the expression of the muscular PEPCK was stimulated in S oyster. In all the situations, the oysters R produce more alanine
Bedu, Elodie. "Adaptation du métabolisme hépatique chez le caneton en croissance au froid." Lyon 1, 2002. http://www.theses.fr/2002LYO10100.
Nobis, Séverine. "Étude du métabolisme protéique au niveau hypothalamique, colique et gastrique dans un modèle murin d'anorexie par une approche protéomique." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR071/document.
Anorexia nervosa, a multifactorial eating disorder, is a major public health problem and results in a severe body weight loss. The severe malnutrition observed in anorectic patients is associated with metabolic alterations inducing disturbance of the gut-brain axis. However, involved mechanisms remained poorly understood. The aim of the present thesis was to better understand the alterations of the gut-brain axis in the activity-based anorexia (ABA) model by evaluating the protein metabolism of various tissues (hypothalamus, colon and stomach) by proteomic approach. Firstly, we have better characterized the response to ABA model according to sex. Then, different proteomic analyses were performed using female C57BL/6 mice. Our results revealed a tissue-dependent adaptation of protein and energy metabolism with an increased hypothalamic activity and a decrease in the gastrointestinal tract. Indeed, ABA mice exhibited an increased expression of proteins involved in mitochondrial metabolism at the level of the hypothalamus, and conversely a decrease of proteins involved in protein and energy metabolism in colonic mucosa with a key role of the mTOR signaling pathway. Both in hypothalamus and colon, autophagy was increased. We were also able to show that gastric emptying was delayed in ABA mice that is mainly due to malnutrition. In addition, proteomic analysis revealed an increase in gastric oxidative stress in female ABA mice. These alterations may contribute to the gastrointestinal functional disorders frequently described in anorexia nervosa. In conclusions, our study underlined tissue-dependent adaptive metabolic process during anorexia that should be further explored
Pichavant-Rafini, Karine. "Contribution à l'étude des capacités adaptatives du turbot (scophthalmus maximus) et du bar (dicentrarchus labrax) à une hypoxie exogène : aspects metaboliques et cellulaires." Brest, 2000. http://www.theses.fr/2000BRES2016.
Tran, Thi Thu Trang. "Adaptation postprandiale du métabolisme intestinal des lipides : rôle du CD36 et du PPAR béta." Phd thesis, Université de Bourgogne, 2011. http://tel.archives-ouvertes.fr/tel-00689160.
Novel-Chaté, Valérie. "Le métabolisme énergétique myocardique en hypoxie chronique : étude chez le rat." Université Joseph Fourier (Grenoble ; 1971-2015), 1996. http://www.theses.fr/1996GRE10267.
Legendre, Claire. "Adaptation cellulaire et moléculaire des cellules d'hépatome humain HepaRG à un environnement hypoxique." Rennes 1, 2009. http://www.theses.fr/2009REN1S055.
Reduced oxygen level, or hypoxia, is frequently encountered in solid tumours and contributes to drug resistance. Hypoxia is also associated with invasive phenotype and correlated to poor prognosis and mortality. The role of hypoxia in hepatocellular carcinoma biology is not fully understood. Therefore, there is a need for developing in vitro models mimicking hypoxic conditions find within solid tumours using hepatic tumour cells. Highly differentiated human hepatoma HepaRG cells respond to hypoxia by a switch from aerobic to anaerobic glycolysis. Moreover, we showed that hypoxia also repressed drug-metabolizing enzymes expression. These repressions could therefore strongly compromise chemotherapy effectiveness on tumour cells within hypoxic environment. Furthermore, HepaRG cells cultured under hypoxic versus normoxic conditions might represent a new strategy to test different types of therapeutic molecules in order to predict their effectiveness
Rager, Marie-Noëlle. "Apport de la résonance magnétique nucléaire à l'étude du métabolisme bactérien." Paris 11, 2006. http://www.theses.fr/2006PA114830.
Knowledge of metabolic features of each bacterial species is of major interest in the medical, environmental and biotechnological fields. This work shows the contribution made by NMR to the investigation of metabolic diversity notably thanks to its overall and noninvasive approach. Sugar metabolism was studied on Plesiomonas shigelloides, Pasteurella multocida, Aeromonas hydrophila and Escherichia coli. 13C NMR allowed us to characterize transport systems, metabolic pathways and flux. 31P NMR allowed us to study cellular energetic state evolution, enzymatic activities and to characterize regulation factors. Thus, new metabolic pathways could be described. These approaches were applied for the study of bacteria on various states: culturable, nonculturable and encapsulated in silica gel
Doriat, Jean-François. "Adaptation fonctionnelle cérébrale et plasticité des récepteurs à la suite de convulsions expérimentales chez le rat au cours du développement." Nancy 1, 1998. http://www.theses.fr/1998NAN10353.
Curutchet, Catherine. "Contribution à l'étude de la migration et du métabolisme des graisses chez le Bruant Ortolan (Emberiza Hortulana)." Bordeaux 2, 1996. http://www.theses.fr/1996BOR2P083.
N'Guessan, Banga Benoît. "Traitement immunosuppresseur et muscles striés : évaluation et adaptation de la fonction mitochondriale du sujet transplanté cardiaque." Université Louis Pasteur (Strasbourg) (1971-2008), 2003. https://publication-theses.unistra.fr/public/theses_doctorat/2003/NGUESSAN_Banga_Benoit_2003_ED414.pdf.
Despite a near-normalization of their cardiac function, heart transplant recipient displayed a limited physical capacity, at maximal exercise. This physical limitation has been in part attributed to altered energetical metabolism in peripheral muscle, which precise mechanisms are still undetermined. However, immunosuppressive treatment, particularly cyclosporin A, and deconditionning have been closely suspected to be the major causes of muscular abnormalities after cardiac transplantation. The aim of this study was to determine the respective contribution of cyclosporin A and deconditionning in physical limitation of heart transplant recipient. To this end, we have characterized the phenotypic and functional properties of their skeletal and cardiac muscles, and have determined the effects of an endurance training program on these various parameters. Our results demonstrate that the intrinsic properties of muscular mitochondria, remain normal in heart transplant recipient, long after transplantation, either at the level of quantitative functional characteristics than at their adaptative mechanisms of regulation of cellular energy production and transfer. This study suggests that the muscular mitochondrial function and its adaptative mechanisms are not directly affected in vivo by clinical immunosuppressive treatment. Others non-mitochondrial actors such as the capillary network and some signaling pathways implicated in phenotypic muscular transition, should represent preferential targets of immunosuppressive drugs in peripheral muscle of heart transplant recipient
Harfouche, Lamia. "Caractérisation de deux nouveaux ARN non-codants régulateurs impliqués dans le métabolisme du fer chez Pseudomonas Brassicacearum." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4034.
Regulatory non-coding RNAs (ncRNA), act as regulators of translation and message stability. They modulate a wide range of physiological responses to environmental stimuli. Due to their biological interest, different bioinformatics tools and experimental approaches have been developed for detecting new ncRNA. Transcriptome analysis of the plan root-associated bacterium Pseudomonas brassicacearum NFM421 strain in response to various stresses, using microarrays containing coding as well as non-coding DNA fragments, revealed the modulation of two potentials ncRNA in response to heavy metals (Cd and U), named IrsZ and IrsY. Furthermore, P. brassicacearum genome was completely sequenced and hundreds of potentials ncRNA have been predicted by using computational tools. This work aims at characterizing the two potentials ncRNA, IrsZ and IrsY, and to determine their function in P. brassicacearum. No homologous was found in the ncRNA database. We validated the expression of the two potential ncRNA by different experimental approaches in different culture conditions and under different stresses. This led to reveal that both IrsZ and IrsY are modulated by iron. Their expression is strongly activated by high concentrations of iron. However, the expression of both Irs ncRNA is suppressed under oxidative stress generated by hydrogen peroxide. This repression is exacerbated in P. brassicacearum overexpressing oxyR. Our work suggests that IrsZ and IrsY act as sensors of intracellular iron status
Feillet, François. "Adaptation métabolique à la malnutrition : modèle des lipides, de la cobalamine, de la riboflavine et des acides organiques dans la malnutrition protéino-énergétique de l'enfant et dans l'anorexie mentale." Nancy 1, 2000. http://docnum.univ-lorraine.fr/public/SCD_T_2000_0296_FEILLET.pdf.
Marusczak, Emmanuel. "Contribution à l'étude des effets de l'hypoxie sur le métabolisme hépatique : adaptation de la périfusion d'hépatocytes isolés de rat." Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE10042.
The liver is a central organ in the regulation of energetic metabolism. Its structure makes it sensitive to oxygen variation. The major aim of this work was to investigate the effects of hypoxia on hepatic metabolism, by changing the amount of perifused hepatocytes. The results show that increasing cells in the perifused resulted in a relative hypoxia during the whole experiment. In these conditions, cells display a significant metabolic activity. Such that gluconeogenesis is inhibited to avoid a further decrease in energetic state and glycolysis is not stimulated by hypoxia. Furthemore, in the presence on dihydroxyaceton, we found that the rédox sate diminished progressively during the experiment. It is in hypothesized that the decrease in the NADH/NAD+ might be a transfert of reducing equivalents from NADH to NAD(P)H to ensure glutathione peroxidase action. The NADH/NAD+ decrease can be prevented by additing octanoate to dihydroxyacetone in the system. This new hepatocyte perifusion model sensitive to oxygen variation, allow us to evaluate metabolic adaptations and might be useful to investigate transcriptional variations due to hypoxia
Morens, Céline. "Assimilation et distribution de l'azote alimentaire en situation de régime hyperprotéique chez le rat et chez l'homme." Paris, Institut national d'agronomie de Paris Grignon, 2002. http://www.theses.fr/2002INAP0006.
Salle, Agnès. "Métabolisme énergétique chez l'obèse et le diabetique de type 2." Angers, 2006. http://www.theses.fr/2006ANGE0054.
Weight change in type 2 diabetic patients (T2D) is distinctive with an inclination towards weight gain with insulin, and conversely a difficulty in weight loss in weight reduction programmes. Our results show that after one year of insulin treatment, resultant weight gain is composed primarly of fat-free mass and it appears not to incrase cardivascular risk. Our results also show that in the early stage of their disease, T2D lose the same amount of weight as obese nondiabetic patients and that in both cases there is non whole body or mitochondrial energy metabolism adaptation that can explain the stabilisation of weight observed from the 5th month onwards. Furthermore, there is no specific adaptation of energy metabolism in T2D as their basal metabolism is not any different to that of obese nondiabetic patients or after weight loss. Insulin resistance is not a determinant of energy metabolism
Philippe, Géraldine. "Influence de la température sur le métabolisme du toluène chez des souches bactériennes psychrotrophes." Rouen, 1998. http://www.theses.fr/1998ROUES057.
Spinicci, Kévin. "Approches computationnelles et mathématiques pour la compréhension du métabolisme de cellules de gliome : caractérisation à partir de données transcriptomiques et focus sur les voies HIF." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALS059.
This Thesis questions the effect of hypoxia on cell metabolism, how different oxygen levels within the tumour lead to heterogeneity, and what is the impact on tumour growth. The study focuses on the main protein orchestrating the cellular adaptation to hypoxia: the Hypoxia Inducible Factor (HIF). Despite being the topic of many studies, HIF seems to be only characterized through its effect on genes observed during biological experiments. Mathematical modelling of HIF does not integrate the protein in models simulating large population of cells. This work will try to unravel some of the mechanisms by which HIF impact the tumour growth with a focus on the metabolim and the cell invasion. In this regard, an agent-based model (ABM) has been developed and the investigation paths for the model have been determined from a statistical analysis.The mathematical model developed describes a network of genes regulated by HIF which includes the two important metabolic genes lactate dehydrogenase (LDH) and pyruvate dehydrogenase (PDH) with a focus on the appearance of the Warburg Effect, a mechanism often considered as a tumour cell characteristic. With that model, we could test different environmental conditions and genetic regulation. We saw that both rapid variations of extracellular oxygen and increased levels of HIF are enough to induce a Warburg phenotype, which therefore appears as influenced by both a contextual effect and a genetic effect.A statistical analysis of glioblastoma transcriptomic data has been performed to unravel the deregulated mechanisms into two datasets: one available on the The Cancer Genome Atlas (TCGA) platform and a Patient Derived Cell Lines (PDCL) dataset provided by the ICM (Paris). The workflow of analysis begins with a Differential Expression (DE) analysis of the transcriptomic data to find the deregulated genes, which are submitted to pathway enrichment tools to determine what are the corresponding pathways. Among the results, collagen biosynthesis was often deregulated in both datasets and cholesterol metabolism was often deregulated in PDCL data. Owing to its link to the current thematic, collagen biosynthesis has been selected as the new candidate for mathematical description in the current model.Thus, following the results of the statistical analysis, the collagen biosynthesis have been implemeted in the model of metabolism. Collagen and matrix remodelling have a noticeable impact on cellular migration and thus the invasion of distant tissues by cancer cells. The three genes P4HA1, MT1-MMP and LOX; have been documented to be upregulated by HIF in the literature and to impact the secretion, degradation and cross-linking of collagen.The results obtained with the new version of the model indicated that collagen density has a substantial effect on the proliferation of the tumour and its shape. Like collagen, oxygen alone could impact the tumour growth. Moreover, results showed that the oxygen and collagen seems to have a dual effect on tumour proliferation. Increased P4HA1 and MT1-MMP quantities, respectively decreased and increased cellular migration speed while LOX seemed to have little effect. Here, no cells adopted a Warburg phenotype in any of the simulations. The similarity of the production of H+ in this model observed when PDH sensitivity to HIF was reduced in the previous model indicates that this may be due to the new parameters values. Consequently, even if the microenvironment favours a Warburg phenotype, genetic regulation may dictates the cell ability to induce it.This model allowed to show how HIF can impact the tumour growth and cellular invasion through few regulations. It suggest that both fast changes of oxygen levels and increased HIF stabilization in normoxia can induce a Warburg Effect. However, the ability of the cell to reduce the oxygen consumption through adaptation to hypoxia seemed to be a limiting factor preventing the adoption of a Warburg phenotype
Davoodi, Fariba. "Effet d'une exposition aux hydrocarbures sur la physiologie cardiaque, le métabolisme énergétique et les performances adaptatives de la sole commune Solea solea." La Rochelle, 2006. http://www.theses.fr/2006LAROS159.
On December 12th, 1999, the oil tanker Erika sank South of Brittany (France). A total of 20 000-30 000 t of heavy oil drifted in the open sea and spread throughout the Northern Bay of Biscay spoiling 500 km of coastline, from western Brittany to the northern tips of the islands of Ré and Oléron. These areas comprise important nurseries for juveniles of numerous fish species, in particular the common sole Solea solea. Experiments were conducted to determine the effects of a 5-day exposure to petroleum hydrocarbon (fuel No. 2; 1/200, vol/vol) in 15 °C-acclimated juvenile sole. Four biological integration levels were investigated. At organism level we observed that standard metabolic rate (SMR) and active metabolic rate (AMR) were reduced and as a result, metabolic scope (MS) was 30 % lower in contaminated than in control sole. The critical oxygen concentration i. E. , the minimum O2 level to sustain SMR, was 3. 5 mg O2 L-1 in fuel-exposed fish and 2. 3 mg O2 L-1 in control fish. At the heart level, changes in cardiac performance were analyzed during a challenge test which consisted in rising water temperature from 15 to 30 °C over a period of 6 hours. The results obtained showed that cardiac output, heart rate and stroke volume were lower in contaminated fish than in control fish. Moreover, fuel-exposed fish were less capable to tolerate quickly increasing water temperature. At the cellular level, the impact of oil exposure upon the contractility of ventricular muscle strips was investigated at 6 and 15 °C and efficiency of the adrenergic regulatory pathway was tested using a low (1 nM) and a high (1 µM) level of adrenaline. The results showed that the relative isometric tensions generated by ventricular muscle strips were lower in contaminated fish than in control fish. Contraction rate and rate of 50 % relaxation were faster in control fish than highly contaminated fish. Moreover, control fish had a higher Ca+2-handling capacity by the SR than contaminated fish. Regulation by adrenaline was impaired in highly contaminated fish. In the field, mesocosm experiments allowed the testing of the long-term effects of the functional and morphological alterations on fish ecological performance (survival and growth). After 3 months in the semi-natural mesocosms, growth of contaminated sole was half that of the control sole and no recovery was observed after 6 months. In summary exposure to hydrocarbons resulted in highly deleterious effects, at both the individual and population levels, due to subtle behavioural and morphological changes affecting feeding behaviours, reproductive success and ability to cope with environmental stressors. Therefore, these results indicate that although petroleum hydrocarbons exert their effects at the cellular level (alterations in the myocardium performance), these effects translate across levels of organismal organisation levels to influence the physiology of the whole animal, and eventually affect its fitness
Troubat, Nicolas. "Régulation autonome du myocarde et activité métabolique lors de tâches à faible coût énergétique." Poitiers, 2009. http://www.theses.fr/2009POIT2295.
The main purpose of this work was to assess the impact of the low cost energy activities (physical and cognitive tasks) on energy metabolism through indirect calorimetry and of automatic regulation of the myocardium through measures of heart rate variability measures. The objective of the first study was to assess the effects of a psychological stress on the physiological responses. The result suggested a stimulation of the sympathetic nervous system with an unchanged of the parasympathetic system activity. Changes recorded in terms of energy substrate and sympathetic nervous system activity appeared to be due to the strong cognitive requirements of the proposed situation. Our second study was intended to test the effects of cold and a cognitive work on the physiological responses during a repetitive work. The results suggested that the combination of cold and cognitive task is responsible for strong cardio-respiratory, energy and muscle adaptations. Low energy cost activities (physical and cognitive tasks) resulted in significant variations of physiological functions which are closed from chronic stress. This project has opened new perspectives of research on the understanding of physiological phenomena governing cognitive activities and human adaptation to the multiplication of stress factors
Kozlak, Maria. "AsiDNA, a Unique DNA Repair Inhibitor, Triggers Sensitization and Bioenergetic Adaptation in Cancer Cells." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS101.
The goal of anti-cancer treatment is long term specificity and efficacy towards cancer cells. Many of the clinically available chemotherapy have encountered obstacles due to their toxicity towards healthy cells or to development of resistance by the cancer cells. This emphasizes the need for development of alternative drugs. Our laboratory developed an original class of DNA repair inhibitor, Dbait, that acts by hijacking and hyper activating DNA repair proteins involved in repairing DNA breaks, such as PARP and DNA-PK. Consequently, this leads to chromatin modification, as revealed by pan-nuclear phosphorylation of H2AX, and inhibition of the recruitment at the damage site of several DNA repair proteins at the damage site. AsiDNA, an active form of Dbait linked to a cholesterol moiety, sensitizes tumours, and not non-tumour cells, to radiation, chemotherapy, targeted therapy. As most of clinical protocols of chemotherapy involve cyclic treatments, the aim of this study was to investigate consequences of cyclic AsiDNA treatment in vitro on non-tumor and tumor cells, conditions that experience cancer patients during chemotherapy. Particular emphasis was paid to emergence of resistant clones during cyclic AsiDNA treatment of tumour cells and emergence of toxicity toward normal cells. At first, various tumor and non-tumor cells were exposed to cyclic treatments consisting of one week of treatment and one week of drug-free recovery. After few cycles of treatment, we didn’t observe toxicity toward normal cells and we failed to isolate resistant clones to AsiDNA from tumor cells. Importantly, this treatment protocol induced resistance of MDA-MB-231 cells to imatinib or PARPi. Unexpectedly, we observed that sensitivity to AsiDNA increased with repeated cycles in tumor cells. This acquired sensitization was stable over time and was never observed in non-tumor cells. In an attempt to understand the specific and acquired sensitization of tumor cells along treatment, we compared non-tumor (MCF-10A) and triple-negative breast cancer (MDA-MB-231) cells that were exposed (3CAsiDNA) or not (3CMT) to 3 rounds of AsiDNA. Transcriptome analysis of MDA-MB-231 revealed global downregulation of transcription after cyclic AsiDNA treatment. Although the expression of genes involved in DNA repair, cell cycle and proliferation, was highly affected, strikingly no clear difference in DNA repair capacity, cell cycle or proliferation rate was observed between MDA-MB-231_3CAsiDNA and MDA-MB-231_3CMT. In contrary, modification of gene expression was weakly affected in non-tumor cells.As impaired DNA repair capacity or cell cycle deregulation couldn’t explain this acquired sensitivity, therefore alternative mechanisms should account for the higher mortality of cyclic treated AsiDNA cells. Cancer cells upregulate energy metabolic pathways to produce enough energy for cell proliferation and repair. Noteworthy, AsiDNA is a PARP activator requiring NAD+ consumption. Based on the fact that metabolic pathways were also deregulated at the transcriptional level, we hypothesized that metabolic exhaustion may be responsible for AsiDNA induced sensitization. Metabolome study revealed deregulation of several metabolites including NAD+. We showed that this bioenergetics deregulation is responsible for increasing sensitivity to AsiDNA. Bioenergetics study confirmed low metabolic activity after repeated AsiDNA treatment due to deregulating aerobic glycolysis and oxidative phosphorylation. As a consequence of energetic deprivation, cancer cells deregulated their malignant behavior by inhibition of migration and tumor formation. We showed that 3CAsiDNA tumor cells are depleted of cancer stem cells, which features are responsible of drug resistance and cancer invasive phenotype. Altogether, we demonstrated that AsiDNA, beside its role in DNA repair inhibition, also interferes with energy metabolism in cancer cells
Cibrario, Alice. "Diversité génétique et phénotypique de l’espèce Brettanomyces bruxellensis : influence sur son potentiel d’altération des vins rouges." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0923/document.
The yeast species Brettanomyces bruxellensis is the most dreaded wine spoilage microorganism because of its repercussions on wine organoleptic wine alteration. It is also present in numerous fermented beverages and its high genetic diversity is partly associated with its ecological origin. Microsatellite analysis of a large collection of isolates (1318) from various geographical origins shows the species’ high genetic diversity, namely among wine strains. Notably, it highlights the coexistence of diploid and triploid individuals worldwide as well as at the region, winery and wine level. Isolation of some of the genotypes in several wine regions in the world suggests this species’ dispersion as well as the putative adaptation of these individuals to the harsh wine environment.The relationship between genetic diversity, matrix type, and physiological traits was further explored. The type of consumable sugars in relation to growth and phenol volatile production capacities of the studied strains, are independent from the ploidy level or ecological origin of the latter. Nevertheless, growth and phenol volatile production profiles (rates and yields) vary, highlighting differences in strains’ growth capacity in different media and aeration conditions. In particular, our data suggests an important adaptation of triploid strains to wine-type environment. From a practical point of view, influence of physicochemical parameters (such as sugars and temperature) on B. bruxellensis’ development in wine has been investigated. In red wine, residual sugar profiles don’t seem to be a relevant tool to estimate the risk associated with “Brett” spoilage. However, the important temperature variations occurring in wine cellars could be a possible explanation for contamination frequency during the first summer of barrel-ageing
Morin, Manon. "Rôle du régulateur post-transcriptionnel CSR dans l'adaptation métabolique de la bactérie modèle Escherichia coli." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0026/document.
In its natural environment, Escherichia coli (E. coli) faces strong fluctuations of the nutrient availability. A complex gene regulatory network makes the bacterium able to switch between a state of growth in the presence of an appropriate carbon source and a non-growth state in its absence. Within this network, the global post-transcriptional regulator CSR (Carbon Storage Regulator) modifies mRNA stability and/or translation initiation by the CsrA protein. This system has been shown to be essential for cells to grow on glucose and is hypothesized to be involved in the regulation of metabolic transitions. However both observations remained unexplored so far. An integrative approach has been used to investigate for the first time the essentiality of CSR on glucose as well as its involvement in the regulation of the glucose-acetate transition. Molecular and phenotypic data for different mutants of the CSR system have been produced and integrated into mathematical models. Transcriptomic and Stabilomic approaches have been used eventually to characterize the importance of the control of mRNA stability during the metabolic adaptation. mRNA stability regulations appear to be of particular importance in gene expression regulation during metabolic adaptation. To conclude, this work shed a new light upon CSR’s involvement in the regulation of E. coli’s metabolism. CSR is definitely essential to regulate glycolysis and thus constitutes another regulator to be integrated into the already complex regulations network of E.coli’s metabolism
Hemmer-Brepson, Claire. "Effets de la température sur la balance oxydative de vertébrés ectothermes aquatiques à différentes échelles spatio-temporelles et conséquences sur les traits d'histoire de vie : modèle poisson." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4354.
Global warming affects the phenology, range and body-sizes of species. However, the underlying physiological processes remain poorly understood. Ectothermic organisms, whose metabolism is positively correlated with temperature, would show an increase in reactive oxygen species (ROS) production under global warming. These ROS have been proposed to be one of the physiological triggers of the life history strategies. In this thesis, we explored the oxidative physiology of fish in different warming contexts and their effects on life-history traits. Our experimental and field approaches on Oryzias latipes, Perca fluviatilis & Rutilus rutilus, allowed us highlight these links. However, further studies are necessary, especially in natura where many confounding effects have made conclusions difficult
Breton, Solène. "Relation entre le métabolisme lipidique membranaire et l’adaptation à la température chez les picocyanobactéries marines du genre Synechococcus." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS503.
Marine picocyanobacteria are the smallest, but also the most abundant photosynthetic organisms on Earth, responsible for nearly 20% of oceanic primary production. Among them, marine Synechococcus display a wide latitudinal distribution that is underpinned by the physiological specialization of phylogenetic lineages along the latitudinal gradient of temperature (i.e. temperature ecotypes). For these photosynthetic cells, the regulation of the membrane fluidity, where the photosynthetic complexes are located, is essential for the cell survival at different temperatures. However, very little data is available on the lipid composition of membranes and its thermoregulation in marine cyanobacteria. My PhD thesis is a comparative thermophysiology study of strains representative of the major clades of the natural communities in the oceans, inhabiting different thermal niches. We showed that the different temperature ecotypes have distinct thermal preferenda and adjust their photosynthetic apparatus depending on the growth temperature. A lipidomic study allowed evidencing the membrane specificities of these marine cyanobacteria. In addition, this study shows that, using nearly 30 molecular species of membrane lipids, the temperature ecotypes have implemented different thermoregulation strategies, which are based on the differential activities of lipid desaturase enzymes. My thesis work suggests that the regulation of membrane fluidity has been an important matter for the colonization of different thermal niches by marine Synechococcus during their evolutionary ecotypic microdiversification
Hajj, Elham. "Influence de la restriction alimentaire et de la réalimentation sur la composition corporelle et la fonction thyroi͏̈dienne chez l'agneau." Montpellier 2, 1992. http://www.theses.fr/1992MON20141.
Boussaid-Om, Ezzine Sourour. "Adaptations environnementales de la protéosynthèse et de la protéolyse dans le muscle de poulet : voies de signalisation impliquées." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4024/document.
Molecular mechanisms underlying the short and long-term environmental adaptation of protein metabolism are not well understood. Prolonged heat exposure (32°C vs. 22°C) modified the expression of some genes related to protein and energy metabolism in the Pectoralis major muscle of chickens. The lower activation of the ribosomal protein S6 by anabolic factors at 32°C could indicate a decrease in the efficiency of mRNA translation into proteins in hot environment. These findings, associated with an impaired potential of protein synthesis, suggest a long-term alteration of muscle protein synthesis under heat conditions. Sequential distribution of diets varying in protein and/or energy contents induced drastic regulations of genes and proteins involved in the control of proteolysis (e.g. atrogin-1) and protein synthesis (e.g. mTOR, S6K1, S6) in the Pectoralis major muscle of chickens. This may indicate a short-term regulation of protein synthesis/proteolysis balance, whose mechanisms and limits remain to be characterized
Lalaouna, David. "Role d' ARN non codants régulateurs dans l' adaptation de Pseudomonas brassicacearum à la rhizosphère et aux fluctuations de l' environnement." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4006.
The plant-beneficial bacterium Pseudomonas brassicacearum forms phenotypic variants in vitro as well as in planta during root colonisation under natural conditions. Transcriptome analysis of typical phenotypic variants using microarrays containing coding as well as non-coding DNA fragments showed differential expression of several genes relevant to secondary metabolism and of the small non-coding RNA (ncRNA) genes rsmX, rsmY and rsmZ, which was characterized by down-regulation. Naturally occurring mutations in the GacS/GacA two-component system accounted for phenotypic switching. The importance of these ncRNAs in the survival of the bacteria to changing environments is denoted by the duplication of rsmX gene, which we called rsmX-2 and whose function has been validated. Our data suggest an exclusive activation of rsmX-1 and rsmX-2 genes by GacA and the involvement of additional regulators in the case of rsmY and rsmZ. Given the functional redundancy of these ncRNAs, we investigated their expression level and stability in different culture conditions and showed differences for the four ncRNAs. In response to nutrient depletion, the four ncRNAs expression is strongly activated and reaches its maximum when the ppGpp is detected in bacterial cells, suggesting a link between the Gac/Rsm system and the "stringent" response. Determining the level of each Rsm ncRNA, which is defined by a balance between synthesis and degradation of each transcript, shows the maintenance of a very important pool of RsmZ compared to other ncRNAs
Hurbain, Julien. "Modélisation de la réponse métabolique à un stress oxydant : rôle des régulations." Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR045.
Living cells such as mammalian cells in particular, are continuously exposed to multiple and varied types of stress. These stresses can perturb the cellular homeostasis and induce damages on the cellular components which could induce several types of diseases. It is particularly the case for a change of cellular redox state called oxidative stress induced by an excessive production or insufficient consumption of reactive oxygen species such as hydrogen peroxide (H2O2).Cells have developed efficient defence mechanisms against oxidative stress that involve anti-oxidant systems such as glutathiones which reduce the oxidizing molecules, but also metabolic pathways such as Pentose Phosphate Pathway (PPP) and glycolysis. These metabolic pathways are known to reroute the carbon flux resources from the glycolysis toward the PPP which induces high NADPH recycling that is required for efficient detoxification rate of the anti-oxidant systems. It remains however unclear how regulatory mechanisms (i) contribute to such reallocation of metabolic flux resources during oxidative stress and (ii) give rise to observed adaptation profiles of intracellular H2O2 concentrations. In the thesis, the role of regulations in the metabolic response to oxidative stress is addressed using a comprehensive kinetic modeling framework. First, a model is built from a set of metabolomics and 13C labeling data, using conventional parameter estimation methods but also a novel metabolic flux analysis techniques based on a stochastic simulation algorithm. Systematic analysis of the model reveals that many metabolic inhibitions, especially on G6PD, PGI and GAPD, can favour flux rerouting for NADPH production. In particular, we show that all these regulations work in a dose-dependent and complementary manner, which explains some paradoxes and controversies, and is consistent with observed adaptation phenotypes. A more phenomenological model has also been developed to show how such adaptation phenotype could contribute to cell-fate heterogeneity, such as fractional killing, as a long-term outcome of oxidative stress
Rouquet, Géraldine. "Etude du rôle de l'opéron métabolique frz dans la virulence d'escherichia coli et dans son adaptation aux conditions environnementales." Thesis, Tours, 2010. http://www.theses.fr/2010TOUR4008.
The metabolic frz operon codes for three subunits of a PTS transporter of the fructose sub-family, for a transcriptional activator of PTS systems of the MgA family (FrzR), for two type II ketose-1,6-bisphosphate aldolases, for a sugar specific kinase (ROK family) and for a protein of the cupin superfamily. It is highly associated with Extra-intestinal Pathogenic Escherichia coli strains. We proved that frz promotes bacterial fitness under stressful conditions, (such as oxygen restriction, late stationary phase of growth or growth in serum or in the intestinal tract). Furthermore, we showed that frz is involved in adherence to and internalization of E. coli in several eukaryotic cells by regulating the expression of type 1 fimbriae. The FrzR activator is involved in these phenotypes. Microarrays, experiments allowed the identification of several genes under the dependence of the frz system. Our data suggest that frz codes for a sensor of the environment allowing E. coli to adapt to a fluctuating environment by regulating some virulence and host adaptation genes. A regulation model is presented
Grimmelpont, Margot. "Réponses physiologiques et comportementales des organismes marins exposés aux vagues de chaleur marines et aux écrans solaires." Electronic Thesis or Diss., La Rochelle, 2023. http://www.theses.fr/2023LAROS002.
Marine heatwaves (MHW) have increased in frequency and intensity since the last century. High atmospheric temperatures drive MHW and are often associated with an increase in coastal recreational activities, leading to the release of Organic Ultra Violet Filters (OUVF) present in sunscreens into bathing waters. Recently, adverse effects have been documented in marine organisms exposed to MHW and OUVF. However, little is known about the ecophysiological and behavioural responses to realistic exposures. The objective of this thesis was to study these responses on two key nearshore species with different ecological functions, the blue mussel (Mytilus edulis) and the golden grey mullet (Chelon auratus). This thesis demonstrated that (1) a realistic MHW caused metabolic or behavioural adjustments in both species, which in turn limited their ability to recover from the MHW and (2) that the behaviour of individuals exposed to environmental concentrations of OUVF increased the risk of bioaccumulating these pollutants in their tissues and induced adverse physiological effects (observed in C. auratus at the cellular and organ level). This work highlights the importance of considering the ability of individuals to cope with stress, by measuring their responses at several organizational levels in order to have a holistic view of the effects
Fouto, Matias Jorge Eduardo. "Adaptation intestinale expérimentale après résection étendue du grêle ; étude "in vitro" du métabolisme entérocytaire de la glutamine par la méthode de la chambre de Ussing/ Jorge Eduardo Fouto Matias." Montpellier 1, 1994. http://www.theses.fr/1994MON1T014.
Renault, David. "Implantation en régions tempérées d'un insecte d'origine tropicale, Alphitobius diaperinus Panzer (coléoptera : Tenebrionidae) : aspects écophysiologiques et biochimiques." Rennes 1, 2002. http://www.theses.fr/2002REN10071.
Lapeyronie, Paul. "Sevrage et séparation maternelle chez l'agneau : incidences nutritionnelles, modifications neuroendocrines et comportementales associées, conséquences zootechniques." Montpellier 2, 1990. http://www.theses.fr/1990MON20214.
Nabulsi, Maisa. "Role of DNA methyltransferase 3a (Dnmt3a) in the adaptation of atherogenesis key players to proatherogenic environment." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066739/document.
DNA methyltransferase 3a (DNMT3A) links environment to phenotypes via catalysis of CpG dinucleotides, notably found in genes promoter regions, methylation and whose hypomethylation is associated with gene transcriptional activation thus enabling the control of gene expression in physiologic and pathologic states. Most of our knowledge about its’ role in disease occurrence are based on articles demonstrating its’ implication in human cancers. Limited data from mouse studies illustrates its’ contribution to certain pathologies. Atherosclerosis constitutes the single most important contributor to the growing burden of cardiovascular disease. Risk factors contribute to disease occurrence, where most are related to environmental influences, notably Dyslipidaemia, a key initiator of atherosclerosis. Abundant data link hypercholesterolemia to atherogenesis, on the other hand, contribution of inflammatory mechanisms that couple dyslipidaemia to atheroma formation has been also appreciated. So far, a growing number of data suggests a role of Dnmt3a in atherosclerosis but to date, its role in cholesterol regulation and early plaque formation has not been clearly elucidated. Our results suggested that deletion of Dnmt3a in monocyte/macrophages does not affect the formation of early atherosclerostic plaque nor does it impact the polarization of macrophages in vitro. In parallel, we have also demonstrated that the deletion of Dnmt3a in hepatocytes leads to significant elevation in TC levels. We were not able to relate this elevation to dysregulation of major genes involved in Cholesterol regulation. On the other hand, we noticed activation of hepatic inflammatory responses
Péden, Romain. "Impact du changement climatique sur le métabolisme des protéines d’une espèce clé des communautés intertidales, Mytilus edulis (L.)." Thesis, Le Havre, 2016. http://www.theses.fr/2016LEHA0015/document.
Intertidal organisms live in a fluctuating environment. The blue mussel Mytilus edulis is a key species of those ecosystems and are largely use as sentinel species. Global warming associated with anthropization will expose mussels to contaminations together with increased temperatures. In addition, more frequent heatwaves are expected. In this work, mussels were collected at two sites depicting contrasted levels of contamination and thermal exposure in microcosm were conducted. Two acclimation scenarios were set up prior to exposure to an identical acute thermal stress. In order to decipher joint effects of acclimation and contamination on protein homeostasis, gill proteome comparisons were performed. High mortality was observed only for mussels collected at the contaminated site and acclimated to current temperatures. Concerning gill proteome analysis, organisms from the pristine site exhibit high abundance of thermal stress proteins. Proteoforms involved in anaerobic metabolism were also up-regulated. Interestingly, mussels acclimated to the higher temperatures show an enhanced response compare to the one acclimated to current temperatures. Concerning mussels from the contaminated site, the response appears more confusing, excepted for heat stress protein response. This may indicate deleterious effects of combined contamination and heat stress. Therefore, organisms acclimated to higher temperature display improved responses. In conclusion, mussels with a clean life history show better physiological abilities than individuals with contaminated life history. Moreover, organisms prepared to heat stress by higher acclimation temperatures also develop a more effective response
Auriol, Clement. "Compréhension globale de l'évolution in vivo d'Escherichia coli lors de cultures sous contraintes de rapports NADPH/NADP+ artificiellement élevés." Thesis, Toulouse, INSA, 2011. http://www.theses.fr/2011ISAT0038/document.
Bacterial metabolism is characterized by robustness and plasticity that allow it to adjust too many metabolic perturbations. This present work demonstrates Escherichia coli abilities of evolution and adaptation under stress of NADPH accumulation. We constructed the E. coli MG1655 Δpgi::FRT ΔudhA::FRT Δedd::FRT Δqor::FRT strain where central metabolism has been rationally engineered to produce two mol of NADPH and two mol of NADH during the oxidation of glucose to acetyl-CoA, while a wild-type strain produces 4 mol of NADH per mole of glucose. Consequently, this strain presents a weak growth on glucose mineral medium. So as to evaluate bacterial abilities to overcome such metabolic stress, in vivo evolution of this strain has been forced in laboratory by serial transfer subcultures. After four evolution subcultures, an individual clone has been characterized by a six fold increased growth rate compared to non-evolved strain. CGS (Comparative Genome Sequencing) analysis allowed us to correlate growth improvement with one mutation apparition in respiratory complex: NuoF*(E183A) in NuoF subunit from the NADH dependant complex I. Further biochemical and physiological studies demonstrated that the evolved respiratory complex is able to oxidize both NADH and NADPH, resulting in a new NADPH reoxydation pathway in the cell. In vivo evolution experiments were then continued until eleven subcultures, where a new individual clone has been characterized by an eleven fold increased growth rate compared to non-evolved strain. Additional CGS analysis allowed us to correlate growth improvement with apparition of two mutations: NuoF*(E183A) and another mutation within the RNA polymerase alpha subunit, rpoA*. Thus, a second E. coli MG1655 ΔpfKA::FRT ΔpfKB::FRT ΔudhA::FRT Δedd::FRT Δqor::FRT strain has been rationally engineered to produce three mol of NADPH and one mole of NADH per mole of glucose oxidized to acetyl-coA. As this train was unable to growth in liquid glucose mineral medium, we performed a solid-state screening on glucose mineral medium that led to two different types of NuoF mutations in strains having recovered growth capacity. In addition to the previously seen E183A mutation other clones showed an E183G mutation, both having NADH and NADPH oxidizing ability. This result highlights need of this new NADPH reoxydation pathway for NADPH accumulating cells. This solution creates a new function for NADPH that is no longer restricted to anabolic synthesis reactions but can now be also used to directly produce catabolic energy. Finally, global understanding of evolution process allowed conception of new engineered strains, well designed for NADPH dependant production of chemicals of interest
Givaudan, Nicolas. "Adaptation strategies of soil biodiversity (earthworms) to pesticides : mechanisms in play and ecosystemic cost assessment." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S083/document.
This work investigated if long-term residual contamination of agricultural soils leads to adaptation of earthworm populations to pesticides. It also aimed at identifying the costs of adaptation from the individual to the population level, and the consequences for the ecosystem. Residual contamination by pesticides was assessed and compared in three fields under conventional management (classified after evaluation of pesticide applications as ''high-'', ''medium-'', and ''low-''pesticide input), one field under organic agriculture requirements and one organic permanent pasture, all in this type of management for more than 20 years. Using a water extraction method, as indicative of the amount of bioavailable pesticides 6, 8 and 4 residues of pesticides were recovered in the ''high-'', ''medium-'', and ''low-input'' fields, respectively, and almost no pesticides were detected in the soil of the organic field except for low levels of residual (possibly 20 years old) atrazine. The endogeic species Aporrectodea caliginosa and Allolobophora chlorotica were found in common to the five fields, -except A. chlorotica which was absent from the organic field-, and were used as biological models. Adaptation strategies were investigated by comparing the populations of these earthworms between the different fields according to several endpoints in field and laboratory assessments. The endpoints measured ranged from the molecular (biotransformation and anti-oxidant enzymes), biochemical (main energy resources), and metabolic (respiration rate, metabolomics) levels, to individual (weight, length) and population-related parameters (cocoon and juvenile life traits), and to the possible consequences for the ecosystem in terms of bioturbation (earthworm burrowing behaviour) and pesticide disappearance as an crucial ecosystem service. Enhanced detoxification and anti-oxidant potential was demonstrated along the gradient of contamination in the fields, and in particular comparing the response to an experimental pesticide exposure between the pre-exposed, thus possibly adapted earthworms from the ''high-input'' field-, and the naïve population from the organic field. Distinct energetic demands and metabolic rearrangements were observed between the populations, more pronounced in the pre-exposed earthworms. Physiological adaptation was demonstrated in pre-exposed animals, and this was associated with an increase in burrowing behaviour and pesticide disappearance in the soil. Population-level consequences were assessed in life traits of the two populations. The conventional farming including the use of pesticides decreased the weight of adult worms in the field and resulted in reallocation of energy resources, possibly from reproductive to metabolic function. This led to lower fecundity and hatching success and could partly explain lower earthworm densities in pesticide-impacted soils
I dette arbejde blev der forsket i om langsigtet residualforurening af landbrugsjord fører til pesticidadaptation hos regnorme. Forskningen sigtede også efter at identificere adaptations-omkostningerne fra individ- til populationsniveau, og konsekvenserne for økosystemet. Pesticiders residualforurening blev vurderet og sammenlignet i; tre konventionelt styrede marker (klassificeret efter evaluering af pesticid-anvendelser som ”højt-”, ”medium-”, og ”lav-input”), en mark styret ud fra økologiske betingelser, og et økologisk permanent græsningsareal, alle havde været styret på denne måde i mere end 20 år. Ved hjælp af en vand-ekstraktionsmetode blev 6,8 og 4 pesticidresiduums udvundet i henholdsvis ”høj-”, ”medium-”, og ”lav-input” markerne, og næsten ingen pesticider blev detekteret i jorden fra den økologiske mark bortset fra lave niveauer af resterende (højst sandsynligt 20 år gammelt) atrazin. Regnorms-populationerne Aporrectodea caliginosa og Allolobophora chlorotica blev fundet i alle fem marker, bortset fra A. chlorotica som ikke var til stede i den økologiske mark. Adaptationsstrategier blev undersøgt ved at sammenligne populationerne af disse regnorme de forskellige marker imellem ifølge flere parametre i felt- og laboratoriebedømmelserne. De målte parametre rangerede fra molekylære- (biotransformation og antioxiderende enzymer), biokemiske- (primære energiressourcer), og metaboliske- (respirationsrate, metabolomics) niveauer, til individuelle- (vægt, længde) og populations-relaterede parametre (puppe og juvenile livskarakterer), og til de mulige konsekvenser for økosystemet med hensyn til bioturbation (regnormes grave-adfærd) og nedgang i koncentrationen af ekstraherbare pesticider. Forbedret afgiftnings- og antioxiderende potentiale blev demonstreret langs gradienten af pesticid forurening i felten. Forbedret afgiftning i den pre-eksponerede population var særdeles tydeliggjort ved eksponeringen til pesticider i laboratoriet sammenliget med den økologiske population. Der blev observeret distinkte energibehov og metabolisk omgruppering populationerne imellem, dette var mere udtalt hos de pre-eksponerede regnorme. Der blev detekteret fysiologiske adaptationer hos de pre-eksponerede dyr, og dette hang sammen med en kompensatorisk øgning i grave-adfærd og nedgang i koncentrationen af ekstraherbare pesticider i jorden. Konsekvenser, på populationsniveau, blev bedømt ud fra de to populationers livskarakterer. Brug af pesticider resulterede i vægtnedgang hos de voksne orme i felten og omfordeling af energiressourcer, formodentlig fra reproduktiv til metabolisk funktion. Dette førte til lavere frugtbarhed og udklæknings-succes og kunne til dels forklare de lavere regnorme-densiteter i den pesticid-påvirkede jord
Pham, Hoang-Nam. "Impact des métabolites secondaires de plantes sur des bactéries pathogènes de la rhizosphère : existe-t-il un lien entre la résistance sur métaux et la modulation de résistance aux antibiotiques ?" Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30153/document.
The objective of this thesis is to evaluate the modification of plant secondary metabolism production contaminated with metallic trace elements (MTE) and its consequences on the associated rhizospheric bacterial communities including bacteria presenting MultiDrug Resistant (MDR) phenotypes. We have focused on two contexts of metals exposure: the phytoremediation of mining sites in Vietnam and the reconversion of agricultural soils contaminated by the atmospheric re-deposition of metallurgical activities in France. Our results highlighted that contamination by different types of metals (mainly Cu and Pb) has led to an alteration in the production of secondary metabolites in the roots, stems and leaves of the hyper-accumulating Pteris vittata and for roots, a similar trend in the metabolic changes could be observed in another type of pollution context (Zn and Pb more particularly). Similarly, the metabolic profiles of the underground parts (roots and rhizomes) of Miscanthus x giganteus were modified by the concentrations of Pb, Cd and Zn in agricultural soils. For the two plants examined chlorogenic acid derivatives have been found in increased proportions in the roots despite soil type and pollution context were highly contrasted. However, catechic tannin derivatives are specifically found in higher proportions in the roots of P. vittata under metal pressure. These polyphenols are known for their ability to scavenge free radicals and their antioxidant properties and thus could be involved in the adaptation of these plants to metallic stress by helping to limit the oxidative stress generated by MTE. At the level of the aerial parts, we studied only the change for P. vittata and evidenced higher proportions of flavonoid derivatives for contaminated plants. Our metagenomic results allow us to conclude also on the effect of MTE on the diversity and the specific richness of the bacterial communities of the studied soils: a high contamination of Cu (10 times the allowed limit) decreased dramatically bacterial richness and diversity, while for more moderate MTE levels including Cu Pb and Zn, the diversity of rhizosphere bacterial communities was more explained by plant or season effect rather than an effect of MTE. This effect on P.vittata rhizosphere bacterial composition is reflected by an enrichment in genera known as opportunistic human pathogens, including Ralstonia, Acinetobacter, Burkholderia and Mycobacterium. In addition, Cupriavidus, known as a highly resistant genus, is the only P. vittata specifically associated genus found in increased proportions at both mining sites compared to non-contaminated rhizosphere soils. This genus could then be involved in the adaptation process of this plant with metal stress. As for the rhizospheric communities of Miscanthus x giganteus, the selection of Stenotrophomonas and Pseudomonas in agricultural soils contaminated with MTE was observed. As a part of this thesis, we have also developed a rapid method for testing the impact of plant metabolites on pathogenic strains of clinical and environmental origin and their efflux pump inhibition (EPI) activity of RND family. Our data thus showed interesting and notable EPI activities comparable to that of the efflux pump inhibitor PAßN for tested compounds issued from Fallopia x bohemica roots or for their derivatives
Brunet, Philippe. "Etude physiologique comparée de l'adaptation au froid chez de jeunes plants de Lycopersicon esculentum Mill. Et Lycopersicon hirsutum Humb. & Bonpl." Montpellier 2, 1990. http://www.theses.fr/1990MON20257.
Liu, Zhenhua. "Evolutionary mechanisms of plant adaptation illustrated by cytochrome P450 genes under purifying or relaxed selection." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ008.
Plants produce a remarkable diversity of secondary metabolites to face continually challenging and fluctuating environmental constraints. However, how plants have reached such a high degree of metabolic complexity and what are the evolutionary forces responsible for this chemodiversity still remain largely unclarified. Gene evolution based on gene birth and extinction has been reported to nicely reflect the natural evolution. Without horizontal gene transfer, young genes are often restricted to a few species and have undergone rapid evolution, whereas old genes can be broadly distributed and are always indicative of essential housekeeping functions. It is thus of interest to study plant adaptation with parallel focus on both taxonomically widespread and lineage-specific genes. P450s are one of the largest protein families in plants, featuring both conserved and branched phylogenies. Examples of P450 properties reflecting metabolic versatility, chemodiversity and thus plant adaptation have been reported. To illustrate evolution of P450 functions in plant metabolism, we selected two P450 genes, one evolutionary conserved CYP715A1 and the second a recently specialized lineage-specific gene CYP98A9 in Arabidopsis thaliana.CYP715s evolved before the divergence between gymnosperms and angiosperms and are present in single copy in most sequenced plant genomes, suggesting an essential housekeeping function highly conserved across seed plants. Based on transcriptome analysis and promoter-driven GUS expression, CYP715A1 is selectively expressed in tapetal cells of young buds and filaments of open flowers during flower development. In addition, CYP715A1 is highly induced in the pericycle cells of the root elongation zone upon salt stress. The salt induction relies on the 2-3kb region of CYP715A1 promoter, suggesting some salt-response elements may exist in this area. To characterize the function of CYP715A1 in Arabidopsis, I identified two T-DNA insertion mutants by genotyping and confirmed by complementation with native CYP715A1 gene. Loss of function of CYP715A1 has no impact on plant growth and fertility in laboratory conditions. However, transmission electron microscopy (TEM) analysis has shown constant undulated intine phenotype in two knockout mutants and also the petal growth is significantly inhibited. These two phenotypes nicely match the native expression pattern of CYP715A1. Gene co-expression analysis suggests involvement of CYP715A1 in gibberellin (GA) metabolism under salt treatment. GAs profiling on mutant flowers also indicates reduced accumulation specific GAs. Unfortunately, no significant phenotype either related to root growth or root architecture under salt treatment can be observed. Recombinant expression of the CYP715A1 enzyme in yeast so far does not allow confirming GAmetabolism. However, metabolic profiling of inflorescences in mutants and over-expression lines, together with transcriptome analysis of the loss of function cyp715a1 mutants strongly support a CYP715A1 role in signaling, hormone homeostasis and volatile emission in agreement with the purifying selection leading to gene conservation observed in spermatophytes.[...]
Chevalier, Clément. "Fonctions et mécanismes d'action de l'ARNIII et de nouveaux ARN non codants de Staphylococcus aureus." Strasbourg, 2009. https://publication-theses.unistra.fr/public/theses_doctorat/2009/CHEVALIER_Clement_2009.pdf.
To date, it is well established that RNA play a key role in gene regulation. In bacteria, more than 10% of the genome is supposed to encode for regulatory RNAs. Whereas in Gram-negative bacteria more than 80 non coding RNAs (ncRNA) have been identified to be involved in various processes (virulence, stress, environmental changes), only few were identified in Gram-positive bacteria when I started my thesis. Thus, the aim of my work was to identify and analyze the function and the mechanisms of action of new ncRNAs in the pathogenic bacterium Staphylococcus aureus. Staphylococcus aureus expresses more than 50 virulence factors that are tighly regulated by proteins but also, in some cases, by RNAs. For example, RNAIII which responds to cell density, was known since several years to regulate by itself the expression of 40 virulence factors. Using different complementary approaches, we have shown that RNAIII acts mainly as an antisens RNA and binds multiple mRNAs encoding either virulence factors or the transcriptional regulator Rot. In each case, RNAIII uses a conserved C rich motif to interact with its mRNA targets. According to the structure of the mRNAs, these interactions lead either to the formation of an extending duplex or a loop-loop complex. These interactions prevent the formation of the ternary complex of translation initiation and further allow a rapid degradation of mRNAs by the RNAse III. Thus, RNAIII and RNase III act in a coordinated way to irreversibly repress the expression of the virulence factors. In addition, by repressing rot mRNA, which encodes for a repressor of toxins, RNAIII indirectly regulates many others genes. These data confirmed that RNAs may be key factors in a complex regulatory network of virulence. In order to unravel whether other non coding RNAs could be involved in virulence regulation, we decided to identify new ncRNAs in S. Aureus. We focused our attention on intergenic regions and using different bioinformatic tools, we finally identified 11 new ncRNAs (RsaA-K) in S. Aureus. Whereas most of these RNA are stable and expressed in stationary growth phase, their size and their conservation vary. Interestingly, most of Rsa RNA carry the same C rich motif than RNAIII suggesting a common mechanism to regulate gene expression. Although the function of most of Rsa RNA is still unknown, we showed that RsaE, whose expression is induced by the agr system, represses the translation of several proteins involved in the metabolism. All together, our data suggest the existence of a link between metabolism, stress response and virulence
Leturque, Armelle. "Adaptations du métabolisme glucidique pendant la gestation chez la ratte." Paris 7, 1985. http://www.theses.fr/1985PA077060.
Andres, Jérémy. "Mécanismes adaptatifs et interactions métaboliques au sein de communautés microbiennes soumises au stress arsénié." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ026/document.
Arsenic naturally occurs in earth crust and is particularly abundant in some environments. While this element is toxic for most forms of life, micro-organisms have evolved different mechanisms to cope with it. This work deals with these different processes involving individual responses as well as interactions between organisms belonging to different domains of life. Descriptive and functional genomics approaches highlight several adaptative mechanisms and cellular functions involved in the arsenic response of a bacterium and a photosynthetic protist, Rhizobium sp. NT-26 and Euglena mutabilis, respectively, both being particularly resistant to arsenic. Also, while Rhizobium sp. NT-26 seems to have lost its ability to interact with plants, E. mutabilis is on the contrary an integral part of a microbial community including different bacteria and benefits from their activity
Blanc, Stéphane. "Le métabolisme énergétique en microgravité simulée : adaptations chez l'homme et le rat." Lyon 1, 1999. http://www.theses.fr/1999LYO1T277.
Willems, Glenda. "Characterisation of zinc and cadmium tolerance in Arabidopsis halleri." Lille 1, 2006. https://ori-nuxeo.univ-lille1.fr/nuxeo/site/esupversions/481f2da5-d398-40e2-b36f-2796fb68be85.
Castelli, Joël. "Radiothérapie adaptative morphologique et métabolique des cancers ORL." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1B043/document.
Objectifs: The aims of this work were (i) to evaluate the dosimetric benefit and to predict the clinical benefit of adaptive radiotherapy for head and neck cancer, regarding both toxicities and local control, (ii) to identify patients whose good candidate for an adaptive strategy, and (iii) to identify the best adaptive strategy to spare the parotid glands. Materials and methods: The dosimetric benefit was assessed using data from a phase III study evaluating the clinical benefit of an adaptive radiotherapy. Cumulated dose with and without adaptive was estimated using deformable image registration. Different methods of deformable image registration were evaluated regarding both spatial and dose estimation accuracy. Predictive model of the risk of parotid gland overdose was computed using generalized linear mixed model and cross validation by leave‐one‐out. The dosimetric benefit of numerous replanning strategies, defined by various numbers and timing of replanning, with regard to parotid gland sparing, was quantified. We performed a systematic review to evaluate the predictive value of quantitative PET parameters. The predictive value of PET intensity parameters was assessed using two independent cohorts of patients. Résultats: Without adaptive radiotherapy, 65% of the patients had a PG overdose of more than 2 Gy and 50% of the patients had a tumor underdose of more than 1 Gy. Adaptive radiotherapy allows to correct both parotid gland overdose and tumor underdose. Based on parameters calculated at the planning and at the first week of treatment, predictive models of PG overdose and tumor underdose were computed. PET parameters correlated with overall survival were identified. Using two independent cohorts of patients, a nomogram to predict survival was build and externally validated. Conclusion: Our studies showed the benefit of adaptive radiotherapy to spare the parotid glands while increasing tumor coverage. These benefits should allow to decrease the toxicities while increasing local control. Early anatomical and dosimetric parameters allow identifying patients at risk of tumor underdose or parotid gland overdose. PET performed before the treatment allows identifying patients with a high‐risk of locoregional failure and death, potentially candidates for treatment. These results justify further studies on a larger cohort of patients, ideally in phase III clinical trials
Martin, Bernabe Alfonso. "Une approche protéomique pour comprendre les adaptations métaboliques du cancer du poumon non à petites cellules." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAS027.
Lung cancers are broadly classified into two main groups: small cell lung cancer and non-small cell lung cancer (NSCLC), which accounts for approximately 83% of all lung cancer cases with an overall 5-year survival rate of 21%. Conventional therapies in NSCLC including radiotherapy and platinum-based chemotherapy lack specificity and often cause severe side effects as they affect healthy cells. To address this problem, targeted therapies have been successfully used due to their specificity for cancer cells. Targeted therapies against epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements have been shown to be effective in NSCLC. However, therapeutic response may be limited due to drug resistance. This is the case of patients whose tumors harbor activating KRAS mutation that leads to constitutive activity of RAS signaling independent of upstream signals. For this reason, a better comprehension of tumor progression and resistance is needed to improve cancer treatments. To date, approaches targeting oncogenic KRAS have been unsuccessful. Given the importance of metabolic reprogramming in multiple cancers including lung cancer and the regulatory role of KRAS signaling. We explored the metabolic reprogramming of KRAS-driven NSCLC cells to find vulnerabilities in the altered metabolism that can be exploited as therapeutic targets.For this, we characterized the proteome of NSCLC cell lines (A549 and NCI-H460) harboring activating mutations of the oncogene KRAS with particular focus on metabolic enzymes. We found not only up-regulation expression of glycolytic enzymes, which is frequently found in cancer as part of the “Warburg effect”, but also a remarkable up-regulation of the pentose phosphate pathway (PPP) in both oxidative and non-oxidative branches. Based on this study, we evaluated the feasibility of use PPP enzyme (glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) and transketolase (TKT)) as targets for improve or develop of new therapies.Recently, protein lysine acetylation (KDAC) has emerged as a metabolism-coordinating mechanism and mounting evidence has shown that acetylation regulation of metabolic enzymes plays a major role in cancer. Consequently, lysine deacetylases inhibitors (KDACIs) have drawn attention not only as promising strategies for therapeutic intervention but also as tool for studying the role of lysine acetylation in NSCLC metabolic reprogramming. Furthermore, metabolic reprogramming also depends strongly on the tumor microenvironment such as oxygen level. Therefore, we also analyzed the inhibition of KDAC under normoxic and hypoxic conditions in order to better understand the adaptive strategies under such perturbations. Our results showed that KDACIs induce low cell proliferation, differentiation, cell cycle arrest and apoptosis accompanied by a change in the tumor metabolic phenotype enhanced under hypoxia. Together, these results allow us to better understand how KDACIs control metabolic pathways under hypoxia in NSCLC
Zangarelli, Aude. "Adaptation des métabolismes protéique et énergétique musculaires aux modifications nutritionnelles au cours du vieillissement." Clermont-Ferrand 1, 2005. http://www.theses.fr/2005CLF1MM13.
Villeneuve, Julien. "CD154 et adaptation cellulaire au stress métabolique : exemple de la stéatose hépatique expérimentale." Bordeaux 2, 2008. http://www.theses.fr/2008BOR21591.
Non Alcoholic Fatty Liver Disease (NAFLD) is a major public health concern. Its prevalence is high and its severity is related to the risk of transition towards cirrhosis and hepatocellular carcinoma. A distinctive histological feature of NAFLD is liver steatosis, resulting from the triglyceride accumulation in hepatocytes. The mechanisms underlying liver steatosis are not yet understood, however, the involvement of the endoplasmic reticulum (ER) stress is being increasingly emphasized. Excess lipid input to the hepatocyte disrupts the ER homeostasis, its loading overwhelming its processing abilities, leading to what is termed the ER stress. ER stress activates the unfolded protein response (UPR) that corresponds to the activation of specific signalization pathways, whose effectors aim at adjusting the functional capacities of the ER. ER stress and the inflammatory reaction are linked, but the underlying mechanisms remain obscure. CD154 is a key mediator of inflammation and, therefore, we studied its involvement in the mechanisms leading to liver steatosis. CD154 knock-out mice developed a steatosis when fed with an olive oil-rich diet. When studying the corresponding mechanisms, we found that CD154 amplified the UPR and, more specifically, increased the unconventional splicing of an effector of the UPR, the X-box binding protein 1. Hence, CD154 increases cell adaptation by controlling the ER homeostasis. Our work highlights a new biological function for CD154, which appears to be an important mediator in the natural history of NAFLD