Bioingénierie des cellules animales :apports complémentaires des approches biologiques expérimentales et théoriques

Doctorat en sciences appliquéesinfo:eu-repo/semantics/nonPublishe

Bioingénierie des cellules animales :apports complémentaires des approches biologiques expérimentales et théoriques

Doctorat en sciences appliquéesinfo:eu-repo/semantics/nonPublishe

Control of 92 kDa collagenase secretion in mammalian cells by modulation of AP-1 activity: An experimentally based theoretical study

Collagenolytic enzymes control cell migration through connective tissues. They appear to be of crucial importance for angiogenesis, tumor metastasis or wound repair. A well-documented stimulation pathway of collagenase secretion, either by natural (cytokines) or synthetic (phorbol esters) molecules, acts through activation of the proto-oncogen activating protein 1 (AP-1). Interestingly, this nuclear factor enhances its own synthesis. It also modulates the activity of different genes, including the one coding for 92 kDa gelatinase. We developed a mathematical model to describe this pathway. It led us to conjecture the existence of an hysteresis cycle for PMA-stimulated collagenase secretion, which was experimentally demonstrated later in MDBK cells in culture. We also modified our model to simulate the behavior of tumoral cells expressing AP-1. In this case, the system becomes highly unstable and, once stimulated, cannot be brought back to rest. This approach paved the way for the understanding and the control of mammalian cell processes, connective tissue maintenance or metastasis dissemination. © 2001 Academic Press.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

“Projet EP2”. Doublement des périodes d’éducation physique dans l’école fondamentale

Objectifs: (1) Evaluer l'impact exercé par l'augmentation de deux à quatre périodes d'éducation physique hebdomadaires sur la condition physique et les attitudes et le style de vie des élèves de la 3ème à la 6ème années primaires. (2) Identifier les modalités d'organisation mises en oeuvre par les écoles pour répondre à cette modification du programme de cours ainsi que les critères de réussite susceptibles d'en renforcer l'efficacité. (3) Recueillir l'avis des acteurs de terrain concernés sur le déroulement de l'expérience afin d'enrichir les recommandations formulées à l'attention des autorités publiques qui devront se prononcer quant à l'exploitation des résultats

Use of Self-Organizing Map to Analyze Images of Fungi Colonies Grown from Triticum aestivum

We submitted to ozone treatment Triticum aestivum (common wheat) seeds severely contaminated by fungi. Fungi colonies developed when seeds were placed over malt agar medium in Petri dishes; Fusarium sp. and Alternaria sp. were identified. However, conventional colonies counting did not allow a clear assessment of the effect of ozone disinfection. We thus used self-organizing maps (SOMs) to perform an image analysis of colonies surface area that clearly showed a significant disinfection effect on Fusarium sp

Genetic Diversity Trends in the Cultivated Potato: A Spatiotemporal Overview

International audienceSimple Summary Monitoring the change in genetic diversity over time and space in crop species is essential to facilitating further improvement. As the world's most important tuber crop for human consumption, and an ideal candidate to help address global food security, the cultivated potato deserves in-depth study in this regard. In this overview, some aspects of spatiotemporal diversity assessment in the cultivated potato are examined with the aim of promoting appropriate strategies for breeding programs in line with challenges relating to sustainable crop production. We investigated the changes in genetic diversity over time and space of the cultivated potato (Solanum tuberosum L.) for the period pre-1800 to 2021. A substantial panel of 1219 potato varieties, belonging to different spatiotemporal groups, was examined using a set of 35 microsatellite markers (SSR). Genotypic data covering a total of 407 alleles was analyzed using both self-organizing map (SOM) and discriminant analysis of principal components (DAPC) de novo and a priori clustering methods, respectively. Data analysis based on different models of genetic structuring provided evidence of (1) at least two early lineages that have been maintained since their initial introduction from the Andes into Europe in the 16th century, followed by later ones coming from reintroduction events from the US in the mid-1800s; (2) a level of diversity that has gradually evolved throughout the studied time periods and areas, with the most modern variety groups encompassing most of the diversity found in earlier decades; (3) the emergence of new genetic groups within the current population due to increases in the use of germplasm enhancement practices using exotic germplasms. In addition, analysis revealed significant genetic differentiation both among and within the spatiotemporal groups of germplasm studied. Our results therefore highlight that no major genetic narrowing events have occurred within the cultivated potato over the past three centuries. On the contrary, the genetic base shows promising signs of improvement, thanks to extensive breeding work that is gaining momentum. This overview could be drawn on not only to understand better how past decisions have impacted the current genetic cultivated potato resources, but also to develop appropriate new strategies for breeding programs consistent with the socio-economic and sustainability challenges faced by agrifood systems

A general artificial neural network for the modelization of culture kinetics of different CHO strains

Animal cell cultures are characterized by very complex nonlinear behaviors, difficult to simulate by analytical modeling. Artificial Neural Networks, while being black box models, possess learning and generalizing capacities that could lead to better results. We first trained a three-layer perceptron to simulate the kinetics of five important parameters (biomass, lactate, glucose, glutamine and ammonia concentrations) for a series of CHO K1 (Chinese Hamster Ovary, type K1) batch cultures. We then tried to use the same trained model to simulate the behavior of recombinant CHO TF70R. This was achieved, but necessitated to synchronize the time-scales of the two cell lines to compensate for their different specific growth rates.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Constitutive release of metalloproteinase-9 (92-kd Type IV collagenase) by Kaposi's sarcoma cells

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Bovine and human endothelial cell growth on collagen microspheres and their infection with the rickettsia Cowdria ruminantium: prospects for cells and vaccine production.

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Modulation of cell cycle for optimal recombinant protein production

info:eu-repo/semantics/publishe