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Literatura académica sobre el tema "Modulation microbienne"
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Artículos de revistas sobre el tema "Modulation microbienne"
GUINARD-FLAMENT, J., P. G. MARNET, I. VERDIER-METZ, C. HURTAUD, M. C. MONTEL, K. STELWAGEN y D. POMIÈS. "La traite, un outil de pilotage du troupeau et de maîtrise de la qualité du lait en élevage bovin laitier". INRAE Productions Animales 26, n.º 2 (17 de abril de 2013): 193–206. http://dx.doi.org/10.20870/productions-animales.2013.26.2.3147.
Texto completoCroteau, Félix R., Geneviève M. Rousseau y Sylvain Moineau. "Le système CRISPR-Cas". médecine/sciences 34, n.º 10 (octubre de 2018): 813–19. http://dx.doi.org/10.1051/medsci/2018215.
Texto completoAhmed, S. G. y U. A. Ibrahim. "A review of the role of infections in the aetiology of haemolysis in patients with sickle cell diseases: pathogenesis, management, and prevention". African Journal of Clinical and Experimental Microbiology 23, n.º 4 (23 de octubre de 2022): 345–57. http://dx.doi.org/10.4314/ajcem.v23i4.3.
Texto completoZENED, Asma, Evelyne FORANO, Céline DELBES, Isabelle VERDIER-METZ, Diego MORGAVI, Milka POPOVA, Yuliaxis RAMAYO-CALDAS, Dominique BERGONIER, Annabelle MEYNADIER y Christel MARIE-ETANCELIN. "Les microbiotes des ruminants : état des lieux de la recherche et impacts des microbiotes sur les performances et la santé des animaux". INRAE Productions Animales, 23 de marzo de 2021, 249–60. http://dx.doi.org/10.20870/productions-animales.2020.33.4.4597.
Texto completoTesis sobre el tema "Modulation microbienne"
Maître, Apolline. "Modulating the vector microbiota for the control of vector-borne pathogens". Electronic Thesis or Diss., Maisons-Alfort, École nationale vétérinaire d'Alfort, 2024. http://www.theses.fr/2024ENVA0005.
Texto completoThe Corsican livestock population, composed of sheep, goats, pigs and cattle, is mainly raised in extensive farming systems. Frequent interactions between livestock, wildlife and human populations can favor the circulation of ticks and tick-borne microorganisms. A high prevalence of tick-borne bacteria of the families Rickettsiaceae and Anaplasmataceae has been reported in goats (Anaplasma ovis), sheep (A. ovis), cattle (Anaplasma marginale, Anaplasma phagocytophilum, and Ehrlichia minasensis) and ticks (Rickettsia spp.) in Corsica. Some of these bacteria (e.g., A. phagocytophilum and Rickettsia sp.) are zoonotic and pathogenic to humans. Currently, there are no preventive measures for the control of ticks and tick-borne diseases. The tick microbiome is a very complex set of interacting microorganisms that impact tick physiology and vector competence. Recently, we have shown that tick microbiota vaccines can produce high mortality in ticks during feeding. Anti-microbiota vaccines can also modulate the tick microbiome and thus can be used as a tool to control the transmission of tick-borne pathogens. In this project, we will use next-generation sequencing of 16S amplicons to study the taxonomic and functional diversity of the microbiome of Rhipicephalus bursa and Hyalomma marginatum, the main pathogen-vector ticks in cattle in Corsica. Using co-occurrence networks and high-throughput pathogen detection, we will then identify keystone bacteria interacting with the detected tick-borne pathogens. The keystone bacteria will be used to formulate antimicrobial vaccines to block pathogen acquisition and/or transmission
Smida, Hassiba. "Modulation de l'interface entre biofilms microbiens électroactifs et surface d'électrode : modifications de surface et effets de milieux". Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S135/document.
Texto completoMicrobial Fuel Cells (MFCs) are bio-electrochemical devices based on electroactive bacterial biofilms which catalyze the electron transfer both at the anode and cathode to generate electrical power. To enhance the biofilms development and to improve the biofilm-electrode connection, being both key features in the performance of the MFC, the graphite anode was functionalized by pyridine units. In order to ensure a robust interface, pyridine units are grafted covalently through the electrochemical reduction of diazopyridinium cations in situ formed from aminopyridine precursors, following the well-known electrografting method for aryl diazonium salts. By comparing the reactivity of various aminopyridine derivatives and the resulting grafted layers properties, the para-diazopyridinium cations reduction results in a thin and compact layer, which is the best suited for promoting bacterial adhesion and favorable electron transfer between the anode surface and electroactive bacteria. The presence of pyridine units immobilized on the anode surface leads to a faster biofilm development together with increased MFC performances for young biofilms. In contrast, anode modified with polyphenylene multilayers and then colonized by a bacterial biofilm has been proved to be less effective for the catalysis of acetate oxidation. On the other hand, the nature of the electrolyte and the physicochemical properties are also important parameters for the bacterial biofilm development. Room temperature ionic liquids have unique properties, particularly in terms of solvation, and their use in biotechnological applications has recently emerged. However, their effects on bacterial biofilms remain little known. The addition of a selection of hydrophilic and hydrophobic ionic liquids based on imidazolium or pyridinium cations in the anolyte, even in very small quantities, or immobilized at the anode surface inhibited the biofilm development
Tchioffo, Tsapi Majoline. "Interactions génomes - environnement dans le système vectoriel Anopheles gambiae / P. falciparum : rôle de la flore microbienne du moustique dans la modulation du développement de P. falciparum". Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20167/document.
Texto completoPlasmodium falciparum, the parasite responsible for the severe form of malaria, is transmitted by Anopheles gambiae, its major vector in sub-Saharan Africa. Novel strategies for malaria control envision interrupting the sporogonic development in An. gambiae, then it is important to better understand vector*environment*parasite interactions that underlie parasite transmission. The aim of this project was to characterize the microbial flora of An. gambiae in natural conditions, to study the role of the main bacterial strains on sporogonic development using natural isolates of parasites and to measure the influence of bacterial exposure on the mosquito immunity and its successive ability to transmit P. falciparum. To carry out this project, we used wild mosquito populations from Cameroon to characterize the mosquito microbial flora, next we challenged female mosquitoes of the Ngousso colony to bacterial strains and then infected the mosquitoes with natural isolates of P. falciparum. Our study showed that Serratia, Pseudomonas and Escherichia isolated from the mosquito midgut reduced infection prevalence and intensity and that the effect of the bacterial exposure on parasite infection levels varied between bacterial strains and gametocyte carriers. The analysis of the 454 sequencing of the different mosquito epithelia revealed intriguing similarities between bacterial communities in the midgut, ovaries and salivary glands of a single mosquito. Expression analyses suggested that immune gene regulation by midgut bacteria could help the mosquitoes to mount an effective antiplasmodial response. Mechanisms involved bacteria-Plasmodium-vector interactions are complex and rely on multiple factors. Deeper investigations on these interactions that allow P. falciparum to complete its cycle in the mosquito vector will be necessary for modeling parasite transmission in the field and for developing new methods for effective malaria control
Attar, Alain. "Analyses et modulations de la fermentation colique chez l'homme". Paris 7, 2007. http://www.theses.fr/2007PA077235.
Texto completoThe colonic fermentation leads to the production of short chain fatty acids (SCFA), gas (CO2, H2 and rarely CH4). Main SCFA (acetate, propionate and butyrate) have tremendous effects in pathophysiology. In healthy volunteer, we showed that the colonic flora could be modulated by prebiotics (fructo- oligosaccharides and lactulose) with an increased in bifidobacteria genius. In diseases, we showed that lactulose was not as efficient as an inert osmotic laxative, provided that the long duration effect would not being deleterious according to the modification of fermentation. We also showed that the flora in excess in small intestinal bacterial overgrowth could be modulated efficiently by antibiotics with the exception that it may be also deleterious as it induces unbalance in the flora. As most of these interventions were done by indirect means in stools or with breath tests, because of colon inaccessibility, we developed an original method of in vivo dialysis by hollow fibers for the recovery of the lumen contents of right colon. We measured by this mean the production of SCFA with the description of the profile of fermentation of the studied fiber
Aznar, Aude. "Etude du rôle des sidérophores microbiens dans la modulation des défenses de la plante Arabidopsis thaliana". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112082/document.
Texto completoIron is an essential element for almost all living organisms, however, it is not bioavailable and is toxic in its free form as it generates reactive oxygen species via the Fenton reaction. To obtain iron, microorganisms secrete small molecules named siderophores with very high affinity for Fe3 +. Siderophores are required for the pathogenesis of several pathogens on animals or plants, but they also are elicitors of defenses. Previous work has shown that siderophores activate defenses and iron deficiency response genes in Arabidopsis thaliana. The activation of defense responses by the siderophore requires a physiological level of iron in the plant indicating that iron is involved in the activation of this process. In my thesis, the global response of the plant A. thaliana to the siderophore deferrioxamine (DFO) has been studied by a transcriptomic approach. The results obtained show that the main process being activated is immunity. By using different iron chelating agents, I have shown that the iron chelation effect is responsible for the activation of immunity. The siderophore treatment also causes disturbance in the homeostasis of iron and other metals in the plant. In an irt1 mutant affected in the transport of heavy metals including iron, activation of defenses by the DFO is compromised. In addition, I studied the effect of iron status of the plant on its susceptibility to the pathogenic bacteria Dickeya dadantii and on the expression of defenses. It appears that iron is required for the establishment of several defense processes in response to D. dadantii. The iron deficient plants are more resistant to infection. A physiological amount of iron in the plant is required for bacterial growth and for expression of the virulence factors, pectate lyases. Iron staining by the Perls' -DAB - H2O2 method shows that low abundance of this metal in plant tissue coincides with the presence of bacteria, which contain high amounts of iron. Overall, our results show that iron is required in the defense arsenal of the plant but it is also a limiting factor for the infectious cycle of D. dadantii
Dobrijevic, Dragana. "Functional analysis of the predicted surface proteome of Gram-positive bacteria from the human gastrointestinal tract. A high-throughput approach to identification of immune modulators". Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112182.
Texto completoIt is now well established that the human gastrointestinal tract microbiota plays an intricate role in human health. However, we are only beginning to understand the molecular mechanisms by which bacteria act on the host cells, knowledge that could provide new directions in treating and preventing disease. The last decade has seen a rapid development of the gut microbiota field, and presently abundant metagenome data and hundreds of genome sequences of individual commensal bacteria are available. Together, these data provide a platform for in silico mining approaches to identify bacterial molecules involved in communication with the host. The challenge is to develop efficient mining and validation strategies, in order to move from correlations and predictions to experimentally validated functional bacteria – host relationships. The work presented in this thesis aims to demonstrate the importance of in silico analyses to broaden our knowledge on bacteria - host interactions. It also shows how this information can be applied in functional studies aiming to identify functional bacterial effector molecules. The main results can be divided in three parts. The first part deals with the development and validation of a host - vector system for functional (meta)genomics studies. The second part describes a functional study where a number of candidate effectors were identified among secreted and surface-exposed proteins from Gram-positive bacteria using an in silico mining approach. It also describes the application of the newly developed host - vector system to evaluate the role of these candidates in immune modulation. Finally, in the third part we present an in silico study that identified new bacterial functions over- or under-represented in a selection of Gram-positive human gut bacteria
Bissaro, Bastien. "On hydrolysis / transglycosylation modulation in glycoside hydrolases : lessons learnt from the molecular design of the first non-Leloir transarabinofuranosylases". Thesis, Toulouse, INSA, 2014. http://www.theses.fr/2014ISAT0023/document.
Texto completoWidening the spectrum of available compounds in the field of Glycosciences is of utmost importance for the entire biology community, because carbohydrates are determinants of a myriad of life-sustaining or threatening processes. The assembly, modification or deconstruction of complex carbohydrate-based structures mainly involves the action of enzymes, among which one can identify Carbohydrate Active enZymes (CAZymes). These enzymes form part of the CAZy database repertoire and include Glycoside Hydrolases (GHs), which are the biggest group of CAZymes, whose main role is to hydrolyze glycosidic linkages. However, some GHs also display the ability to perform synthesis (transglycosylation), an activity that mostly manifests itself as a minor one alongside hydrolysis, but which is the only activity displayed by a rather select group of GHs that are often called transglycosylases. Understanding how transglycosylases have resulted from the process of evolution is both intringuing and crucial, because it holds the key to the creation of tailored glycosynthetic enzymes that will revolutionize the field of glycosciences.In this thesis, an extensive review of relevant scientific literature that treats the different aspects of GH-catalyzed transglycosylation and glycosynthesis is presented, along with experimental results of work that has been performed on a family GH-51 α-L-arabinofuranosidase, a pentose-acting enzyme from Thermobacillus xylanilyticus (TxAbf). The conclusions of the literature are presented in the form of a hypothesis, which describes the molecular basis of the hydrolysis/transglycosylation partition and thus provides a proposal on how to engineer dominant transglycosylation activity in a GH. Afterwards, using a directed evolution approach, including random mutagenesis, semi-rational approaches, in silico predictions and recombination it has been experimentally possible to create the very first ‘non-Leloir’ transarabinofuranosylases. The mechanistic analysis of the resultant TxAbf mutants notably focusing on the hydrolysis/transglycosylation partition reveals that the results obtained are consistent with the initial hypothesis that was formulated on the basis of the literature review.To demonstrate the applicative value of the experimental work performed in this study, the TxAbf mutants were used to develop a chemo-enzymatic methodology that has procured a panel of well-defined furanosylated compounds. Enzyme-catalyzed transfer of arabinofuranosyl moities can be used to generate arabinoxylo-oligosaccharides (AXOS), but the design of non-natural oligosaccharides, such as galactofuranoxylo-oligosaccharides or arabinofuranogluco-oligosaccharides is also possible. Overall, the work presented constitutes the first steps towards the development of more sophiscated methodologies that will procure the means to synthesize artificial arabinoxylans, with a first proof of concept being presented at the very end of this manuscript.In the present context of the bioeconomy transition, which relies on technologies such as biorefining and green chemistry, it is expected that the glycosynthetic tools that have been developed in this work will be useful for the conversion of pentose sugars obtained from biomass. The synthesis of tailor-made arabinoxylo-oligo- and polysaccharides may lead to a variety of potential applications including the production of prebiotics, surfactants or bio-inspired materials and, more fundamentally, the synthesis of artificial models of plant cell wall