Dissertations / Theses on the topic 'Analyse en cellule unique'
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Bontoux, Nathalie. "Analyse du transcriptome d'une cellule unique à l'aide d'une puce microfluidique." Paris 6, 2006. http://www.theses.fr/2006PA066600.
Full textLu, Cong. "Analyse microélectrochimique du stress oxydant à l'échelle de la cellule unique : application aux cellules cancéreuses du sein." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00828217.
Full textMeistermann, Dimitri. "Modélisation du développement préimplantatoire humain à partir de données de transcriptome de cellule unique." Thesis, Nantes, 2020. http://www.theses.fr/2020NANT1019.
Full textCe travail de thèse est consacré à l’étude de nouveaux mélanges gazeux pour la gravure plasma du CdHgTe, à savoir : CH₃NO₂/H₂/Ar, CH₃OH/H₂/Ar et CH₄/NO₂/H₂/Ar. L’objectif est de graver sans polarisation du substrat pour limiter l’énergie déposée sur les surfaces gravées. Une première partie portant sur l’analyse de ces plasmas par sondes électrostatiques et spectroscopie d’émission optique a permis de montrer que la substitution de nitrométhane ou méthanol au méthane a un effet sur la composante chimique de la gravure. Pour ces nouveaux mélanges hydrocarbonés, l’apparition de molécules telles que CO et CN est corrélée à l’annihilation du dépôt spontané de polymère. La seconde partie, consacrée à la gravure du CdHgTe avec ces nouveaux précurseurs a prouvé la faculté de graver sans polarisation du substrat avec les mélanges CH₃NO₂/H₂/Ar et CH₄/N₂O/H₂/Ar et ainsi réduire les dommages engendrés au matériau, notamment la rugosité en surface. Une étude plus poussée de la gravure en mélange CH₄/N₂O/H₂/Ar montre notamment une augmentation de la vitesse de gravure pour les faibles polarisations jusqu’à un certain seuil, avant qu’elle ne stagne, correspondant au passage d’une gravure à dominance chimique à une gravure à dominance physique. De plus, la rugosité est indépendante de la puissance d’excitation du plasma, de la température du substrat ainsi que de la durée de gravure. Enfin, la gravure de tranchées a permis de mettre en évidence la gravure chimique et isotrope à faible polarisation avec les mélanges CH₄/N₂O/H₂/Ar et CH₃NO₂/H₂/Ar mais qui, à plus forte polarisation présente une meilleure passivation latérale que les gravures en plasma CH₄/H₂/Ar
Crozatier, Cécile. "Contrôle et analyse électrochimique de la réactivité biologique à l'échelle de la cellule unique dans un dispositif microfluidique." Phd thesis, Université Paris-Diderot - Paris VII, 2007. http://tel.archives-ouvertes.fr/tel-00178656.
Full textGrâce au développement d'outils modulables de culture cellulaire et de manipulation de cellules vivantes dans des dispositifs microfluidiques, nous avons mis en place le contrôle dynamique stable de stimulations chimiques sur une population de cellules souches mésenchymateuses (CSM) en culture et poursuivons cette étude dans le but d'induire la réactivité cellulaire des CSM vers la voie de différenciation neuronale.
Le développement d'un microsystème intégré de détection électrochimique du stress oxydant sur cellules uniques est mis en oeuvre à travers la réalisation d'un dispositif microfluidique intégré consistant en un réseau de chambres de mesures, contenant des microélectrodes fonctionnelles, et permettant d'isoler des macrophages uniques et de les maintenir en survie pendant plusieurs dizaines de minutes, durée suffisante pour réaliser nos mesures électrochimiques. En faisant varier les conditions de mesure, comme le nombre de cellules sondées dans le même micro-environnement, la nature du stimulus ou la présence ou non de communication cellulaire avec une population voisine, nous posons les bases d'une analyse originale jamais réalisée jusqu'à présent.
Martineau, Eugénie. "Linking single cell directionality to dynamic multicellular transitions in Myxococcus xanthus : a multiscale analysis." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0089.
Full textThe δ-proteobacteria Myxococcus xanthus has been a model of study for decades for its self-organized behavior as a response of environmental stimuli. It colonizes favorable ecological niches by using surface motility. In particular, this motility allows M.xanthus to predate collectively over prey microorganisms, while under starvation they start a developmental process to form macroscopic fruiting bodies, filled with environmental resistant myxospores. All these multicellular behaviors require a dynamic control of the cell polarity established by the polarity proteins MglA, MglB and RomR. Together, they define the direction of movement of the cell, which can be rapidly inverted by the Frz chemosensory system (reversion). In this thesis work, through combined computational/experimental approaches, we highlight that the regulation system forms a new type of biochemical oscillator, controlled by two proteins RomR and FrzX, which act together through complementary action to trigger the reversion at the lagging pole. The unique architecture of this system allows a wide response to various stimuli, which could be very beneficial for collective cell behaviors. To understand the importance of these transitions, we have developed a new high-resolution single cell assay linking single cMARTINEAU EUGENIE 2018AIXM0089/016ED62 2018/03/21 62 SCES SCHell behaviors to multicellular structures at unprecedented spatial and temporal resolutions. This way, we have investigated the role of the newly identified biochemical oscillator in the multicellular model of predation
Ben, Meriem Zacchari. "Memory of stress response in the budding yeast Saccharomyces cerevisiae." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC311.
Full textCellular memory is a critical ability displayed by micro-organisms in order to adapt to potentially detrimental environmental fluctuations. In the unicellular eukaryote S. cerevisiae, it has been shown at the population level that cellular memory can take the form of a faster or a decreased response following repeated stresses. We here present a study on how yeasts respond to short, pulsed hyperosmotic stresses at the single-cell level. We analyzed the dynamical behavior of the stress responsive STL1 promoter fused to a fluorescent reporter using microfluidics and fluorescence time-lapse microscopy. We established that pSTL1 displays a dynamical variability in its successive activations following two short and repeated stresses. Despite this variability, most cells displayed a memory of past stresses through a decreased activity of pSTL1 upon repeated stresses. We showed that this memory does not require do novo protein synthesis. Rather, the genomic location is important for the memory since promoter displacement to a pericentromeric chromatin domain leads to its decreased transcriptional strength and to the loss of the memory. Interestingly, our results points towards an unreported involvement of the SIR complex on the activity of pSTL1 only when displaced to the pericentromeric domain in our experimental conditions. This study provides a quantitative description of a cellular memory that includes single-cell variability and points towards the contribution of the chromatin structure in stress memory. Our work could serve as a basis to broader studies on the positioning of stress response genes at subtelomeric positions in the budding yeast, from a genetic point of view as well as an evolutionary one
Dufour, Adrien. "Déchiffrer le réseau moléculaire contrôlant la pluripotence du porc." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL035.
Full textCurrent global changes are forcing us to rethink our production systems and the way we select and phenotype animals. The use of pluripotent stem cells capable of self-renewal and differentiation into a multiplicity of cell types is an asset that will make it easier to assess phenotypes that are difficult to measure in livestock farming. To improve our knowledge of the biology of porcine pluripotent cells, I carried out a transcriptome analysis at the single-cell level on porcine embryos. This analysis enabled me to identify new cellular subpopulations in extra-embryonic tissues, to highlight signalling pathways and cellular interactions specific to each population, and to link them to gene regulation modules. Based on these data and the literature, we were able to develop a culture medium for the amplification and maintenance of porcine embryonic stem cells (pESC). I then carried out a transcriptome and epigenome analysis at cell level on porcine embryos and our pESC lines, enabling me to establish the link between epigenetic and transcriptional differences between embryonic populations and to study their evolution during development. I was also able to compare the phenotype of pESCs with the epiblast of the porcine embryo, which enabled me to identify their differences and similarities in terms of signalling pathways and gene regulation modules. I also identified two subpopulations in the ESC lines with specific epigenetic signatures and gene regulatory modules. Taken together, these results highlighted the importance of cell-cell interactions for embryo development and pluripotent cell biology, and identified new gene regulatory modules associated with pluripotency. Finally, the identification of two pluripotent cell subpopulations in our cultures raises the question of the heterogeneity of these cell lines and the possible consequences for their fate and potential
Bonnaffoux, Arnaud. "Inférence de réseaux de régulation de gènes à partir de données dynamiques multi-échelles." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEN054/document.
Full textInference of gene regulatory networks from gene expression data has been a long-standing and notoriously difficult task in systems biology. Recently, single-cell transcriptomic data have been massively used for gene regulatory network inference, with both successes and limitations.In the present work we propose an iterative algorithm called WASABI, dedicated to inferring a causal dynamical network from timestamped single-cell data, which tackles some of the limitations associated with current approaches. We first introduce the concept of waves, which posits that the information provided by an external stimulus will affect genes one-byone through a cascade, like waves spreading through a network. This concept allows us to infer the network one gene at a time, after genes have been ordered regarding their time of regulation. We then demonstrate the ability of WASABI to correctly infer small networks, which have been simulated in-silico using a mechanistic model consisting of coupled piecewise-deterministic Markov processes for the proper description of gene expression at the single-cell level. We finally apply WASABI on in-vitro generated data on an avian model of erythroid differentiation. The structure of the resulting gene regulatory network sheds a fascinating new light on the molecular mechanisms controlling this process. In particular, we find no evidence for hub genes and a much more distributed network structure than expected. Interestingly, we find that a majority of genes are under the direct control of the differentiation-inducing stimulus. Together, these results demonstrate WASABI versatility and ability to tackle some general gene regulatory networks inference issues. It is our hope that WASABI will prove useful in helping biologists to fully exploit the power of time-stamped single-cell data
Bost, Pierre. "Decoding cellular communications and interactions between immune cells by using single-cell approaches." Electronic Thesis or Diss., Sorbonne université, 2020. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2020SORUS020.pdf.
Full textCellular communications are essential to the proper functioning of multi-cellular organisms, particularly in order to adapt to a constantly changing environment. The cells of the immune system are no exception to this rule, but the interactions between immune cells remain little known and complicated to study. The recent emergence of 'single cell' sequencing technologies represents a unique opportunity to study these communications. In this thesis, different experimental and analytical approaches have been developed to study these communications on a single cell scale. These strategies were then applied to different disease contexts, including COVID-19, Alzheimer's disease or immunisation with inactivated pathogens, and identified previously unknown or poorly understood cellular communication pathways. However, the effectiveness of these approaches is limited by the lack of information on cell location and further work integrating such data will be essential to go further in the dissection of immune cell communications
Aquino, Yann. "Bases génétiques et évolutives de la variabilité interpopulationnelle de la réponse immunitaire au SARS-CoV-2." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS488.
Full textHumans display substantial interindividual clinical variability after SARS-CoV-2 infection, the genetic and immunological basis of which has begun to be deciphered. However, the extent and drivers of population differences in immune responses to SARS-CoV-2 remain unclear. Here we report single-cell RNA-sequencing data for peripheral blood mononuclear cells—from 222 healthy donors of diverse ancestries—that were stimulated with SARS-CoV-2 or influenza A virus. We show that SARS-CoV-2 induces weaker, but more heterogeneous, interferon-stimulated gene activity compared with influenza A virus, and a unique pro-inflammatory signature in myeloid cells. Transcriptional responses to viruses display marked population differences, primarily driven by changes in cell abundance including increased lymphoid differentiation associated with latent cytomegalovirus infection. Expression quantitative trait loci and mediation analyses reveal a broad effect of cell composition on population disparities in immune responses, with genetic variants exerting a strong effect on specific loci. Furthermore, we show that natural selection has increased population differences in immune responses, particularly for variants associated with SARS-CoV-2 response in East Asians, and document the cellular and molecular mechanisms by which Neanderthal introgression has altered immune functions, such as the response of myeloid cells to viruses. Finally, colocalization and transcriptome-wide association analyses reveal an overlap between the genetic basis of immune responses to SARS-CoV-2 and COVID-19 severity, providing insights into the factors contributing to current disparities in COVID-19 risk
Tamra, Amar. "Spectroscopie diélectrique hyperfréquence de cellules individualisées sous électroporation." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30011/document.
Full textElectroporation is a physical process that consists in applying electric field pulses to transiently or permanently permeabilize the plasma membrane. This phenomenon is of great interest in the clinical field as well as in the industry because of its various applications, in particular electrochemotherapy which combines electrical pulses with the administration of a cytotoxic molecule in the treatment of tumors. The evaluation of this phenomenon is raditionally carried out using optical and biochemical methods (microscopy, flow cytometry, biochemical test). They are very effective but require the use of a wide range of fluorochromes and markers, which can be laborious and costly to implement, while being invasive to the cells. In recent years, the development of new biophysical tools for the study of electroporation has taken place, such as dielectrophoresis and impedance spectroscopy (low frequency). In addition to the ease of implementation, these methods are of interest in the study of membrane modifications of the cell. Hence the advantage of operating beyond the GHz, in the range of microwaves, for which the cytoplasmic membrane becomes transparent and the intracellular content is exposed. The extraction of the relative permittivity as a result of the electromagnetic field / biological cell interaction then reflects the cell state. This technique, microwave dielectric spectroscopy, is a relevant method for analyzing the effects of electroporation on cell viability. Moreover, it does not require any use of the exogenous molecules (non-invasive) and the measurements are directly carried out in the culture medium of the cells. Two objectives were defined during this thesis whose work is located at the interface between three scientific fields: cellular biology, microwave electronics and micro-technologies. The first objective concerns the transposition of conventional electroporation to the micrometric scale, which has shown an efficiency as efficient as the first. The second part of the work concerns the study by HighFrequency dielectric spectroscopy of cells subjected to different electrical treatments (combined or not with a cytotoxic molecule). This work presents a statistical power and shows a very good correlation (R2> 0.94) with standard techniques used in biology, which biologically validates the HF analysis method in the context of electroporation. This work also shows that microwave dielectric spectroscopy proves to be a powerful technique capable of revealing cell viability following chemical and / or electrical treatment. They open the way to 'non-invasive' analysis by hyper-frequency dielectric spectroscopy of electroporated cells in situ
Pagliaro, Sarah Beatriz De Oliveira. "Transcriptional control induced by bcr-abl and its role in leukemic stem cell heterogeneity. Single-Cell Transcriptome in Chronic Myeloid Leukemia: Pseudotime Analysis Reveals Evidence of Embryonic and Transitional Stem Cell States Single Cell Transcriptome in Chronic Myeloid Leukemia (CML): Pseudotime Analysis Reveals a Rare Population with Embryonic Stem Cell Features and Druggable Intricated Transitional Stem Cell States A novel neuronal organoid model mimicking glioblastoma (GBM) features from induced pluripotent stem cells (iPSC) Experimental and integrative analyses identify an ETS1 network downstream of BCR-ABL in chronic myeloid leukemia (CML)." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASQ032.
Full textChronic myeloid leukemia is a clonal hematopoietic malignancy, characterized by the acquisition of the t (9;22) translocation leading to Ph1 chromosome and its counterpart BCR-ABL oncogene, in a very primitive hematopoietic stem cell. CML is a model of targeted therapies as the proof of concept of the feasibility of targeting the tyrosine kinase (TK) activity BCR-ABL using TK inhibitors (TKI) has been shown to lead to major responses and remissions. However, the current problems encountered in these therapies are primitive leukemic stem cells resistance and their persistence which is thought to be related to the heterogeneity of the stem cells at diagnosis leading to clonal selection of cells resisting to TKI therapies. I have applied the technology of single cell transcriptome analysis to CML cells using a panel of genes involved in different pathways combined with trajectory inference analysis to the gene expression pattern. The results showed a transitional stem cell states including embryonic genes identified in CML cells at diagnosis which could contribute to LSC resistance and persistence. Furthermore, the oncoprotein Bcr-Abl is the constitutively active tyrosine kinase produced by the chimeric BCR-ABL gene in chronic myeloid leukemia (CML). The transcriptional targets of Bcr-Abl in leukemic cells have not been extensively studied. A transcriptome experiment using the hematopoietic UT7 cell line expressing BCR-ABL, has identified the overexpression of eukaryotic elongation factor kinase 2 (eEF2K) which plays a major role in the survival of cells upon nutrient deprivation. Overall, the data suggest that overexpression of eEF2K in CML is associated with an increased sensitivity to nutrient-deprivation
Ozier-Lafontaine, Anthony. "Kernel-based testing and their application to single-cell data." Electronic Thesis or Diss., Ecole centrale de Nantes, 2023. http://www.theses.fr/2023ECDN0025.
Full textSingle-cell technologies generate data at the single-cell level. They are coumposed of hundreds to thousands of observations (i.e. cells) and tens of thousands of variables (i.e. genes). New methodological challenges arose to fully exploit the potentialities of these complex data. A major statistical challenge is to distinguish biological informationfrom technical noise in order to compare conditions or tissues. This thesis explores the application of kernel testing on single-cell datasets in order to detect and describe the potential differences between compared conditions.To overcome the limitations of existing kernel two-sample tests, we propose a kernel test inspired from the Hotelling-Lawley test that can apply to any experimental design. We implemented these tests in a R and Python package called ktest that is their first useroriented implementation. We demonstrate the performances of kernel testing on simulateddatasets and on various experimental singlecell datasets. The geometrical interpretations of these methods allows to identify the observations leading a detected difference. Finally, we propose a Nyström-based efficient implementationof these kernel tests as well as a range of diagnostic and interpretation tools
Koh, Alaric C. W. "Analyses électrochimiques d’espèces réactives de l’oxygène et de l’azote produites par un macrophage immunostimulé." Paris 6, 2009. http://www.theses.fr/2009PA066465.
Full textRichard, Angélique. "Analyse de la variabilité de l’expression génique et du métabolisme glycolytique au cours du processus de différenciation érythrocytaire : de l’analyse à grande échelle aux questions mécanistiques." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1058/document.
Full textThe meaning of cell decision making consists in the capacity of every living cell to integrate environmental information and to transform it in a coherent biological response. Nowadays it is increasingly demonstrated that cell populations present a significant quantitative and qualitative heterogeneity that could be involved in living organisms functions. Thus, the first part of my thesis consisted in studying gene expression variability at the single-cell level during the differentiation process of primary avian erythroid progenitor cells. The expression of 92 genes was analyzed using RT-qPCR in cells isolated at different differentiation time-points. The main results of this study showed that gene expression variability, as measured by Shannon entropy, reached a maximal level, simultaneously to a drop in the number of correlated genes, at 8-24h of differentiation. This increase of the gene expression variability preceded the irreversible commitment of cells into differentiation, identified between 24h and 48h. This analysis also highlighted the potential importance ofLDHA(Lactate dehydrogenase A) encoding a glycolytic enzyme, in erythroid progenitors self-renewal and at the critical differentiation time-point 8-24h. Therefore the second part of my thesis consisted in analyzing the role of LDHA in erythroid progenitors self-renewal and the variations of glucose metabolism during the differentiation process. Our first results suggested that erythroid differentiation might be accompanied with a metabolic change, corresponding to a switch from anaerobic glycolysisdepending upon LDHA, toward aerobic energy production, relying upon oxidative phosphorylation
Robert, Michèle. "Etude quantitative des constituants épithéliaux et mésenchymateux dans l'hypertrophie bénigne de la prostate : comparaison des résultats obtenus sur pièces d'adénomectomie et biopsies uniques et multiples." Montpellier 1, 1995. http://www.theses.fr/1995MON1T038.
Full textDeprez, Marie. "Étude de l’hétérogénéité cellulaire et des dynamiques de régénération de l’épithélium respiratoire sain par analyses des signatures transcriptionnelles sur cellules uniques." Electronic Thesis or Diss., Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR6022.
Full textImprovements made in nucleic acid sequencing and cell handling technologies now offer the opportunity to analyze simultaneously the content of numerous single cells (RNA, DNA, ...) by global and unbiased approaches. This single-cell ‘omics’ revolution provides a new framework to revisit the “Cell Theory”, elaborated over several centuries, and essentially based on morphological and functional features. The many cell modalities now accessible at single- cell level, such as their transcriptome, spatial localization, developmental trajectories, enrich considerably this definition, and set a renewed context to precisely reassess the definition of ‘cell types’, ‘cell states’ as well as their different interactions and fates.My thesis work initially set up ad hoc approaches and statistical framework to analyze appropriately these single-cell data, which deeply differ from standard bulk RNA-seq. High variance, presence of a huge percentage of null values, large volume of data are among the specific characteristics of these datasets. My work was centered on the main experimental model of my host laboratory, e.g. the human airway epithelium. Human airways are lined by a pseudostratified epithelium mainly composed of basal, secretory, goblet and multiciliated cells. Airways also constitute a true cellular ecosystem, in which the epithelial layer interacts closely with immune and mesenchymal cells. This coordination between cells ensures proper defense of the respiratory system and its correct regeneration in case of external aggression and injuries. A better understanding of the operating sequences in normal and physiopathological situations is relevant in pathologies such as chronic obstructive pulmonary disease, asthma or cystic fibrosis.First, I characterized at a single cell level the precise and cell-specific sequence of events leading to functional regeneration of the epithelium, using a 3D model of human cells. I then built a single-cell atlas of the different cell types that are lining healthy human airways from the nose to the 12th generation of bronchi.By applying computational and statistical approaches, I have identified cell lineage hierarchies and was able to reconstruct a comprehensive cell trajectory roadmap in human airways. I not only confirmed previously described cell lineages, but I have also discovered a novel trajectory that links goblet cells to multiciliated cells, identifying novel cell populations and molecular interactors involved in the process of healthy human airway epithelium regeneration. The profiling of 12 healthy volunteers then generated a dataset of 77,969 cells, derived from 35 distinct locations. The resulting atlas is composed of more than 26 epithelial, immune and stromal cell types demonstrating the cellular heterogeneity present in the airways. Its analysis has revealed a strong proximo-distal gradient of expression in suprabasal, secretory, or multiciliated cells between the nose and lung airways. My work has also improved the characterization of rare cells, including “hillock” cells that have been previously described in mice.In conclusion, this work probably represents one of the first single-cell investigations in human airways. It brings original contributions to our understanding of differentiation’s dynamics and cellular heterogeneity in healthy human airways. The resulting resource will be extremely useful for any future single-cell investigators and also for establishing a very useful joint between clinical and biological works. As such, it will constitute a reference in any future project aiming to precisely analyze specific disease conditions
Mascalchi, Patrice. "Analyse par suivi de particule unique à la surface de lymphocytes vivants de l'organisation dynamique des récepteurs CD4 et CCR5 impliqués dans l'infection par le VIH." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1560/.
Full textInfection of CD4+ T lymphocytes by the human immunodeficiency virus (HIV) is initiated by the sequential interaction of the viral envelope protein gp120 with the primary receptor CD4 and then a coreceptor, CCR5 in most cases of primo-infection. The necessity of this double interaction suggests that the efficiency of the HIV entry process could depend on the dynamic membrane organization of these two receptors. To study this organization at the surface of living lymphocytes, we used single particle tracking (SPT), a high resolution and non-invasive microscopy approach. Firstly, we validated the choice of Quantum dots (QD) for SPT experiments based on the results of a systematic study that evaluated the influence of the particle on the measured diffusion coefficient. Secondly, we determined and analyzed the movement of CD4 and CCR5 receptors labeled with QD, at the surface of lymphocytes immobilized on glass coverslips. These experiments showed that both receptors exhibit three different diffusion modes: random, permanently or transiently confined diffusion. Addition of molecules that destabilize the CD4-CCR5 interaction (soluble CD4, maraviroc) revealed that it is partially responsible for their confinement. All these observations allow us to establish the basis for a model of the dynamic membrane organization of CD4 and CCR5 at the surface of living lymphocytes. These data represent a starting-point for the understanding of the presumed relationship between the dynamic organization of the receptors and the first steps of the HIV infection process
Gouin, Carla. "Tropisme cellulaire initial du SARS-CoV-2 dans le poumon humain : du poumon entier aux sous-populations de macrophages." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASL147.
Full textThe pathogenic mechanisms of the initial phase of the SARS-CoV-2 infection remain poorly understood at the pulmonary level, despite strong research efforts since the emergence of the COVID-19 pandemics. Studies conducted with various models, including isolated human cell cultures, explants, organoids or lung-on-a-chip systems have generated conflicting results concerning the primary pulmonary targets of the virus and the induced innate immune responses.In my thesis, I evaluated an original model for studying the early stages of viral infection. This model involves the infection of a whole lung that is maintained ex vivo with a technique used in lung transplantation, allowing the study of infection under conditions that preserve spatial interactions. This technique (ex-vivo lung perfusion, EVLP) involves ventilating and perfusing lungs for several hours and has the potential to evaluate and rehabilitate marginal lungs. We conducted single-cell RNA-seq analyses and we discovered that the whole lung maintained under EVLP without the virus displayed a specific gene activation program, which we analyzed in the first part of my thesis. We found that EVLP in itself induced an inflammatory response that varied over time and across cell types. This response was accompanied by gene signatures indicating reduced signaling of cytoskeleton in alveolar type 2 epithelial cells and endothelial cells, as well as reduced cell migration and activation of lymphocytes and dendritic cells. This work reveals, for the first time, the biological responses to EVLP based on cell types that may be related to the clinical outcomes. In the second part of my thesis, we infected lungs under EVLP with different viral isolates and conducted single-cell RNA-seq analyses. These analyses revealed that alveolar macrophages (AMs) and monocyte-derived macrophages (MoMacs) are the primary targets of the virus. Epithelial cells and pulmonary monocyte subpopulations were not significantly associated with the virus. We studied the response of the monocyte/macrophage populations in vitro after dissociation of human lung tissue, flow cytometry sorting and culture with the virus. We observed specific inflammatory responses depending on cell subsets, viral strain and doses, with MoMacs being the most inflammatory. Our original work reveals the role of monocyte/macrophage subsets in the initial phases of the SARS-CoV-2 infection and suggests that the initial response of alveolar monocyte/macrophages will drive the subsequent development of lung injuries, depending on the composition in AMs and MoMacs, the viral strain and doses. In a parallel project, we investigated the effects of a method aimed at reducing the inflammation during EVLP, on porcine lung, by performing a dialysis of the perfusate to remove accumulated metabolic wastes. However, our findings showed that dialysis did not reduce inflammation; rather, it increased inflammation after 6 or 12 hours.Overall, this thesis project has demonstrated the strengths and limitations of a whole lung viral infection model maintained ex-vivo. It has highlighted the involvement of monocyte/macrophage subpopulations in the initial step of SARS-CoV-2 infection and has also contributed to a better understanding of the cellular and molecular mechanisms involved in the ex vivo lung maintenance technique, which will be useful for improving lung transplantation procedures
Cussat-Blanc, Sylvain. "Créatures Artificielles : Développement d'Organismes à partir d'une Cellule Unique." Phd thesis, Université des Sciences Sociales - Toulouse I, 2009. http://tel.archives-ouvertes.fr/tel-00449673.
Full textBenites, Luiz Felipe. "Genomic insights into mamiellophyceae organismal interactions." Thesis, Sorbonne université, 2019. https://tel.archives-ouvertes.fr/tel-03330155.
Full textMamiellophyceae algae are the basis of coastal marine environments. Despite their ecological importance, the aspects related to their organismal interactions remain enigmatic. Single cell genomes (SCGs) from uncultivated samples can identify biotic associations, from sex to parasitism. In protists, sex is determined by the mating types (MTs), which are present in Ostreococcus. Here, we used genetic data to answer: How did MTs evolve in this group? Can we find interaction signals in the SCGs? The analysis of the MT genes suggests an old divergence of the Ostreococcus MTs, and the presence of new MTs. Finally, using SCGs, we identified new viruses associated with Ostreococcus. We provide here a framework for the evolution of sex in this class and, using SCGs, we have identified new associations in environmental Mamiellophyceae
Huet, Sébastien. "Analyse des mouvements des granules de sécrétion à proximité de la membrane plasmique par microscopie de fluorescence à excitation par onde évanescente." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2006. http://tel.archives-ouvertes.fr/tel-00090014.
Full textMadrid, Canales Ignacio. "Model of Cellular Growth under Stress : Emergence of Heterogeneity and Impact of the Environment." Electronic Thesis or Diss., Institut polytechnique de Paris, 2024. http://www.theses.fr/2024IPPAX008.
Full textThis thesis focuses on understanding individual-scale cell growth under stress. Starting from the analysis of the data collected by Sebastián Jaramillo and James Broughton under the supervision of Meriem El Karoui, we have developed various models to comprehend the impact of the heterogeneous response to genotoxic stress (SOS response) on the growth of a Escherichia coli populations. We employ measure-values stochastic processes to model the dynamics of these populations.Firstly, we construct a stochastic model based on the "adder" size-control model, extended to incorporate the dynamics of the SOS response and its effect on cell division. The chosen framework is parametric, and the model is fitted by maximum likelihood to individual lineage data obtained in mother machine. This allows us to quantitatively compare inferred parameters in different environments.Next, we explore the ergodic properties of a more general model than the "adder," addressing open questions about its long-time behaviour. We consider a general deterministic flow and a fragmentation kernel that is not necessarily self-similar. We demonstrate the existence of eigenelements. Then, a Doob dollar_h_dollar-transform with the found eigenfunction reduces the problem to the study of a conservative process. Finally, by proving a "petite set" property for the compact sets of the state space, we obtain the exponential convergence.Finally, we consider a bitype age-structured model capturing the phenotypic plasticity observed in the stress response. We study the survival probability of the population and the population growth rate in constant and periodic environments. We evince a trade-off for population establishment, as well as a sensitivity with respect to the model parameters that differs for survival probability and growth rate.We conclude with an independent section, collaborative work initiated during CEMRACS 2022. We investigate numerically the spatial propagation of size-structured populations modeling the collective movement of Myxobacteria clusters via a system of reaction-diffusion equations
Caccianini, Laura. "Imagerie de l'architecture dynamique de la chromatine dans la cellule unique." Thesis, Paris Sciences et Lettres (ComUE), 2019. https://tel.archives-ouvertes.fr/tel-02896692.
Full textChromatin structure and cellular function are tightly linked in the nucleus of mammalian cells. Disruption of chromatin spatial organisation dramatically affects the life of a cell and eventually leads to severe pathologies in entire organisms. Two nuclear factors, CTCF and Cohesin, have been found to play a crucial role in the regulation and maintenance of DNA architecture. Huge advancements have been made in the understanding of the mechanisms behind chromatin arrangement but the field is still lacking a dynamic picture at the single cell and single molecule level. This study provide this study provides insight into the dynamics of CTCF and Cohesin through single particle tracking of CTCF and Cohesin dynamics achieved with single molecule tracking in living mouse embryonic stem cells. The interplay between these two factors was studied by looking at Cohesin’s behaviour in the absence of CTCF and in the context of other biological alterations
Vigne, Aurélie. "Microfluidic tools for the engineering of enzymes of therapeutic interest." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0391/document.
Full textThis thesis deals with the development of microfluidic tools for the engineering ofenzymes of therapeutic interest. Droplet microfluidics has enormous potential in the field ofquantitative biology. We are developing microfluidic tools based on the directed evolutionof the enzyme L-asparaginase, an enzyme used to treat acute lymphoblastic leukemia. Thistreatment is based on an enzyme of bacterial origin, which leads to immune reactions thatresult in the interruption of treatment, often fatal for the patient. However, a human version ofthe enzyme L-asparaginase, which is less immunogenic, is currently not sufficiently active to beused. The main objective of this thesis is to analyze and screen enzyme mutant libraries usingstandard mutagenesis methods and to analyze each mutant individually through microfluidics.For this, several microfluidic systems have been developed and optimized for different selectioncriteria for the analysis and selection of the enzyme L-asparaginase. The bacterial versionserving as a positive control for the optimization of microfluidic workflows to analyze andscreen mutant libraries of the human version of the enzyme L-asparaginase
Farina, Francesca. "Transport de l'ADN dans le cytoplasme d'une cellule eucaryote." Paris 6, 2011. http://www.theses.fr/2011PA066283.
Full textSenecal, Adrien. "Régulation transcriptionnelle du proto-oncogène c-Fos à l’échelle de la cellule unique." Paris 6, 2013. http://www.theses.fr/2013PA066786.
Full textThe expression level of the 21,000 genes present in a human cell must be precisely controlled according to several extra- and intracellular signals. Failures in the control of gene expression are often involved in diseases such as cancer. The choice of genes, as well as their expression level, are the result of the regulation of RNA polymerase II by a combination of transcription factors. Usually, these events are studied over large cell populations, thus masking variations between cells of the same population. In my work, I particularly focused on the transcriptional regulation of the c-Fos proto-oncogene at the single cell level. To this end, we developed a tool for quantifying single mRNA and nascent RNA on transcription site from Fluorescence in situ Hybridization data. With this program, we discovered a remarkably simple regulation of c-Fos transcription. Multiple transcripts are produced during short and infrequent transcriptional bursts. We have shown that while the burst size is not regulated, their frequency is modulated by the level of activation of intracellular signaling pathways. We also observed a dynamics clustering of RNA polymerase II on genes. This clustering may provide an explanation for the molecular origin of these transcriptional bursts as well as providing a framework to decipher their regulation
Cruard, Jonathan. "Le Myélome Multiple et son environnement immunitaire à l’échelle de la cellule unique." Electronic Thesis or Diss., Nantes Université, 2023. http://www.theses.fr/2023NANU1033.
Full textMultiple myeloma (MM) is a hematological cancer in which the tumor cell is derived from the long-lived plasma cell. This pathology is characterized by strong heterogeneity at various levels. This heterogeneity includes alterations intrinsic and extrinsic to tumors, which have an impact on patient prognosis and response to treatment. The development of single-cell sequencing technologies has enabled us to explore new aspects of this diversity. The work presented here first explores the diversity of response to dexamethasone within the MM.1S cell line of MM. This work shows that within this homo- geneous tumoral population there is a diversity of response to treatment. Secondly, we worked on MM together with its immune environment at the single-cell level. In order to better understand how the immune environment evolves during the course of the disease, but also under the pressure of treatment. This as- pect is even more essential as the most recent treatments directly involve the immune environment by redirecting it against the tumor. A better characterization of the immune environment could therefore enable us to better predict the response to treatments, as well as their consequences for the immune environment
Angarita, Gil Karol Philipe. "Modélisation électrique et analyse d'une cellule lithium." Mémoire, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/5506.
Full textMonnet, Benjamin. "Fluides newtoniens et suspensions : bulle unique et vidange." Electronic Thesis or Diss., Lyon, École normale supérieure, 2024. http://www.theses.fr/2024ENSL0014.
Full textMultiphase flows (gas/liquid/solid) are omnipresent in natural and industrial process. Despite all the studies on this topic, its complex and rich physics still rises a lot of questions. We studied the rise of single bubbles in a confined environment as well as the emptying of a tank. In both cases, Newtonian fluids and suspensions are examined and compared. First of all, the speed and shape of a freely rising bubble in a vertical cell filled with Newtonian fluid have been looked in details. A theoretical model taking into account the fluid inertia predicting the bubbles speed has been established and experimentally verified. Besides, the bubbles shape strongly depends on the regime, with elongated bubbles in the direction of their movement in the viscous regime and flattened bubbles in the inertial regime. Surprisingly, the liquid flow generated by the bubble does not change significantly. The following chapter of the manuscript focuses on the rise of single bubbles in a geometry tilted with respect to the gravity. Bubbles shape slightly changes but only for the most confining geometries. The tilting induces additional friction that we modeled theoretically. Next, we focused on the rise of individual bubbles in a suspension. An experimental method designed to distinguish the particles in a suspension has been implemented in order to locally measure the volume fraction of grains. Finally, our work aimed at understanding the emptying of a tank filled with Newtonian fluid or suspension. In the former case, we quantified the decrease of flow rate and frequency of bubbles with the viscosity. In the latter case, two distinct regimes are noticeable: first, the suspension flows like a Newtonian fluid and latter, some particles emerge, fastening the emptying but making it incomplete
Pierrat, Sébastien. "Etude de l'adhésion cellulaire à différentes échelles de la molécule unique à la cellule." Paris 6, 2004. http://www.theses.fr/2004PA066485.
Full textLehmann, Nathalie. "Development of bioinformatics tools for single-cell transcriptomics applied to the search for signatures of symmetric versus asymmetric division mode in neural progenitors." Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLE070.
Full textIn recent years, single-cell RNA-seq (scRNA-seq) has fostered the characterization of cell heterogeneity at a remarkable high resolution. Despite their democratization, the analysis of scRNA-seq remains a challenge, particularly for organisms whose genomic annotations are partial. During my PhD, I observed that the chick genomic annotations are often incomplete, thus resulting in a loss of a large number of sequencing reads. I investigated how an enriched annotation affects the biological results and conclusions from these analyses. We developed a novel approach based on the re-annotation of the genome with scRNA-seq data and long reads bulk RNA-seq. This computational biology project capitalises on a tight collaboration with the experimental team of Xavier Morin (IBENS). The main biological focus is the search for signatures of symmetric versus asymmetric division mode in neural progenitors. In order to identify the key transcriptional switches that occur during the neurogenic transition, I have implemented bioanalysis approaches dedicated to the search for gene signatures from scRNA-seq data
Moussy, Alice. "Caractérisation des premières étapes de différenciation des cellules hématopoïétiques à l'échelle de la cellule unique." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEP029/document.
Full textDespite intensively studies, the fundamental mechanisms of cell fate decision during cellular differentiation still remain unclear. The deterministic mechanisms, often based on studies of large cell populations, cannot explain the difference between individual cell fates choices placed in the same environment. The aim of my thesis work is to study the first steps of hematopoietic cell differentiation at the single cell level thanks to transcriptomic, proteomic and morphological analyses. Two differentiation models have been used: T regulatory lymphocytes and human cord blood-derived CD34+ cells. The behavior of individual cells following stimulation has been analyzed. Using time-lapse microscopy coupled to single cell molecular analyses, we could demonstrate that the cell fate choice is not a unique, programmed event. First, the cell reaches a metastable “multi-primed” state, which is characterized by a mixed lineage gene expression pattern. After transition through an “uncertain”, unstable state, characterized by fluctuations between two phenotypes, the cell reaches a stable state. Our observations are coherent with a stochastic model of cell fate decision. The differentiation is likely to be a spontaneous, dynamic, fluctuating and not a deterministic process. The cell fate decisions are taken by individual cells
Meunier, Anne. "Méthodes analytiques pour la détection de phénomènes biologiques de sécrétion à l'échelle de la cellule unique." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00858915.
Full textBois, Nadège. "Développement d'un système de gouttes en microfluidique pour la récupération et l'étude de la cellule unique." Paris 6, 2013. http://www.theses.fr/2013PA066776.
Full textStudies of cell populations are necessary to better understand normal and pathological biological mechanisms. However, one must take into account the specificity of each cell within a population. The study of their heterogeneity can provide meaningful information and it is therefore essential to investigate the gene expression levels of individual cell. This is a major challenge given the small amount of material in a single cell. The aim of our project was to develop innovative and integrated tools based on microfluidics to perform gene expression analyzes at the single cell level. For that purpose we used droplet microfluidics that enables the generation of small droplets of water in oil at high throughput. We developed a platform enabling single cell encapsulation and providing an easy handling of individual droplets. This system was then used for two different applications: first, we investigated the capabilities of this platform to make monoclonal cultures for the creation of stable cell lines or the production of monoclonal antibodies. Second, we targeted an application devoted to transcriptom analysis: once encapsulated in droplets, cells can be lysed and their RNA content can then be converted to complementary DNA, amplified by RT PCR, recovered and analyzed on microarrays. This strategy provides a gene expression profile in individual cells
Jacquey, Frédéric. "Développement d'une technique de microspectrophotométrie rapide destinée à l'étude des signaux ioniques cytoplasmiques sur cellule unique." Lyon 1, 1994. http://www.theses.fr/1994LYO10092.
Full textSeeleuthner, Yoann. "Rôle des protistes hétérotrophes marins dans le cycle du carbone océanique par génomique en cellule unique." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLE002/document.
Full textUnicellular eukaryotes (protists) have important roles in the biogeochemical cycles of the ocean. First, although on average less abundant than cyanobacteria, photosynthetic protists account for a large proportion of net primary production. Since they are relatively easier to culture, photosynthetic organisms are relatively more studied and their genomes represent a large fraction of the genomes of marine protists available in databases. On the other hand, heterotrophic organisms require much more work for cultivation and are therefore much less well known. Moreover, the majority of genomes of heterotrophic protists sequenced to date concern organisms of interest to humans (plant pests, pathogenic organisms), but the choice of these organisms as study models does not reflect their ecological interest.The objective of this thesis is to study, using a single-cell genomic approach, several heterotrophic picoeucaryotes, that are highly abundant in the open oceans and have not yet been cultivated. For this purpose, a protocol for sequencing, assembling and annotation of genomes from single cells has been developed.The genomes of seven stramenopile lineages have been partially reconstructed and annotated, making it possible to confirm in a robust way the phylogeny of stramenopiles obtained by ribosomal markers, and, more important, to formulate hypotheses regarding their specialization in terms of mobility or trophic mode.Particularly, the comparison of gene repertoires of carbohydrate degradation indicates likely different food spectra in the organisms studied.In addition, the combined use of these genomes and metagenomic sequences from the Tara Oceans expedition made it possible to describe the geographical distribution of these organisms as well as the genetic distance between environmental populations and our reference genomes. The correlation of these distributions with the environmental parameters measured at the sampling points shows that temperature is a key factor in the distribution of these microorganisms. In addition, the use of metatranscriptomic data from the expedition allowed us to distinguish different expression profiles - potentially corresponding to different physiological states - in the most cosmopolitan lineage studied.In conclusion, this thesis shows that there is a strong genomic diversity to be explored in heterotrophic marine protists, allowing us to make hypotheses about their trophic modes. It also demonstrates the value of single-cell genomics, in particular its complementarity with metagenomic and metatranscriptomic approaches for the comprehensive understanding of marine ecosystems
Mary, Pascaline. "Génération de gouttes en microfluidique pour l'étude de la cellule unique, l'extraction liquide-liquide et la vectorisation." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://pastel.archives-ouvertes.fr/pastel-00005739.
Full textTrouchet, Amandine. "PCR digitale pour la détection et la caractérisation de micro-organismes pathogènes au niveau de la cellule unique." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC170/document.
Full textWe aim to develop a prototype of droplet-based microfluidic system capable of detecting and colocalizing multiple genetic markers at the single cell/bacteria level, using the Polymerase Chain Reaction (PCR) in a digital multiplexed version. This cannot be achieved using current commercial digital PCR systems, and should increase the sensitivity and reliability of the detection of pathogens. Importantly, the system will guarantee the presence of multiple markers within the same genome and enable accurate identification, and bring the false positive rate close to zero. As a first application, we will demonstrate the possibility to co-localize 3 virulence genes in the E.coli strain O157:H7, a major foodborne pathogen, which has to be detected in clinical feces samples or food samples, which may also contain non pathogenic E. coli carrying only a subset of these virulence genes. E. Coli will be encapsulated in micrometric droplets, lysed by heating in situ prior performing a multicolour end-point Taqman assay. Our objective is to demonstrate that this test can be successfully applied to real clinical or food samples
Guille, Manon. "Détection par microélectrodes de flux atto-à femtomolaires de neuromédiateurs sur cellule unique et dans un tissu vivant." Paris 6, 2005. http://www.theses.fr/2005PA066207.
Full textChen, Tong. "Développement de biocapteurs hyperfréquences microfluidiques pour la spectroscopie diélectrique non-invasive de la cellule unique : applications en cancérologie." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/2172/.
Full textDevelopment of microwave microfluidic bio-sensors for non-invasive dielectric spectroscopy of single cell: Applications in Cancerology. Biological analysis at the level of the single cell, allowing the understanding of cellular mechanisms, is of great importance in the fields of biology, medicine and especially in oncology. Microtechnology has opened up the prospect of such devices and many researches are underway on the development of analysis systems which are non-invasive, rapid, label-free or has no cell damage. The convergence of bio-microwave sensors with microfluidics can meet these challenges. We developed jointly (1) micro-devices for microwave dielectric spectroscopy of biological fluids and (2) microfluidic systems for manipulation of cell populations and single cell in the culture medium. The electromagnetic fields engineering was conducted to optimize the fluid volume analysis and the detection sensitivity. Microfabrication performed at LAAS-CNRS allowed controlled positioning of single cell in the analysis area. We finally demonstrated experimentally significant dielectric contrast between cancer cells alive and RL lymphoma apoptosis with more tracking capability longitudinal of apoptosis. These researches work on non-invasive analysis of single cell, the discriminatory capacity of different biological states, the possibility of temporal tracking of biological mechanisms open new perspectives for the cell analysis in cancerology
Laplatine, Loïc. "Résolution spatiale en microscopie par résonance de plasmon de surface à couplage par prisme." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENY044/document.
Full textPrism-based surface plasmon resonance (SPR) microscopy is an optical imaging technique invented in the late 60s'. Its main advantage lies in its high sensitivity to optical index or thickness variations at a metal surface. Therefore, the monitoring of biological reactions can be performed in real-time without labeling agent such as fluorescence or enzymes. Over the last 30 years, SPR microscopy has become the major technique in label-free biodetection. The field of application range from the determination of affinity constant in biochemistry to the detection of pathogenic bacteria via cellular biology. Until now, the propagation length of the surface plasmons has been considered as the spatial resolution limit. However, many examples do not support this statement. In this PhD thesis, we demonstrate that the resolution is also limited by optical aberrations induced by the prism used to couple light and surface plasmons. Thus, we are able to explain why the experimental resolution was usually worse than the predicted one. The analysis of the image formation and the quantification of aberrations lead us to suggest two new optical configurations optimized for resolution. We also analyze which metal exhibits the better trade-off between propagation length and sensitivity. Experimentally, we obtain a resolution between 1.5 and 4 μm depending on the direction, on field-of-view up to several mm2, and with a standard sensitivity for biodetection (monolayer of DNA). We are then able to observe simultaneously several thousands of individual eukaryote and prokaryote cells. Finally, we develop a prototype dedicated to the real-time monitoring of protein secretion by immune cells. The limits of SPR microscopy and the solutions which could allow this kind of study are discussed. Preliminary results on the improvement of bacterial detection are also presented
Daumas, Frédéric. "Diffusion latérale du récepteur ư aux opioi͏̈des analysée par suivi de particule unique à la surface de cellules vivantes : relation organisation dynamique-fonction." Toulouse 3, 2002. http://www.theses.fr/2002TOU30180.
Full textG protein coupled receptors are involved with other partners in a signal transduction pathway whose mechanism is still not completely understood. We used single particle tracking to study the real time lateral movements of the æ opioid receptor on the surface of fibroblast cells stably transfected by a T7-tagged æ opioid receptor. Two populations could be distinguished : 10% of the receptors exhibit a directed diffusion mode and 90% have a "walking confined diffusion" mode combining a short term confined diffusion with a long term random walk. .
Eid, Joelle. "Etude du relargage du VIH-1 en temps réel à l'échelle de la cellule unique par la Viro-fluidique." Thesis, Université de Montpellier (2022-….), 2022. http://www.theses.fr/2022UMONT007.
Full textUpon its entry, HIV-1 replicates and produces new viral particles that are released into the extracellular environment. The crucial step of virus release remains poorly understood because it requires the study at the single cell level. Indeed, quantification of viral production from cell populations with very heterogeneous HIV-1 replication kinetics would give approximate results. This is why we have developed a microfluidic approach that allows the study of HIV-1 release dynamics in real-time at the single cell level. In this study, continuous microfluidics was combined to the virology in order to develop a sensitive and reliable technology to visualize and quantify virus production by a single cell. Three types of chips were fabricated: the trapping chip allowed us to determine the physical and biological parameters that ensure single cell trapping (~10 µm) producing VLPs-GFP. The detection chip, whose performance was compared with the Nanoparticle Tracking Analysis technique, proved to be a valuable tool for accurate and reproducible quantification of fluorescent VLPs (~140 nm) at the single particle scale in cell culture supernatants. The multiplex chip, which combines the two previous chips, allowed us to study in real-time the virus release kinetics at the single cell scale. VLPs-GFP producing HeLa and HEK 293 cell lines were used as study models. For the first time, viral production kinetics could be measured with an average of 50 VLPs / cell / h that was validated by the measurement of viruses produced by the same cells grown in culture dish, confirming the reliability and sensitivity of our approach. Interestingly, the release kinetics profile shows a periodic process (period ~4min) that could be explained by the presence of one or more limiting steps in the virion biogenesis mechanism. The new tools developed here provide novel information on the kinetics of HIV-1 salting-out. They can be used or easily adapted for the study of other pathogens or extracellular vesicles
Marchal, Laurence. "Interaction cellule-hôte/parasite : analyse de la réponse de la cellule mammifère à l'invasion par le protozoaire Apicomplexe Toxoplasma gondii." Paris, Muséum national d'histoire naturelle, 2000. http://www.theses.fr/2000MNHN0012.
Full textGrouard, Géraldine. "Analyse des populations de cellules dendritiques d'amygdales." Angers, 1996. http://www.theses.fr/1996ANGE0506.
Full textRuben, Elisee. "Analyse du métabolisme mitochondrial de la cellule épithéliale en réponse au peptidoglycane." Paris 7, 2011. http://www.theses.fr/2011PA077176.
Full textThis thesis questions bacterial PAMPs (Pathogen associated molecular pattern molecules) ability to modulate mitochondrial metabolism. Our study shows that bacteria such as Escherichia coli, possibly through peptidoglycan release, can induce drastic mitochondrial morphological changes, enlargement and rounding, that are associated with mitochondrial respiration inhibition into epithelial cells. Metabolic changes induced b; peptidoglycan and E. Coli treatments are revealed by the induction of a cellular dependency on glucose availability for survival. Importantly, we showed that the PRRs (Pathogen recognition receptors) Nod1 and Nod2 are involved in this cellular dependency. Whether the Nod proteins themselves participate to cell metabolism switch to glycolysis remain a fascinating area of research to further investigate. Their involvement would reveal a novel fonction of the Nod proteins in cell metabolism with a potential role in cancer cell bioenergetics
Paillasson, Sylvain Alain. "Analyse in situ de l'organisation des acides nucléiques dans la cellule vivante." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE19001.
Full textFiszman, Nicolas. "Etude de cinétique de la traduction eucaryote à l'échelle de la molécule unique." Phd thesis, Palaiseau, Institut d'optique théorique et appliquée, 2013. http://pastel.archives-ouvertes.fr/pastel-00939858.
Full textLeclère, Lucas. "Evolution de la reproduction sexuée des hydrozoaires : aspects historiques, analyse phylogénétique et développementale." Paris 6, 2008. http://www.theses.fr/2008PA066472.
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