Mucoidy and cytotoxicity arise from two independent modifications of the phenotype of the bacterium Pseudomonas aeruginosa that contribute to the mortality and morbidity of cystic fibrosis. We show that, even though the transcriptional regulatory networks controlling both processes are quite different from a molecular or mechanistic point of view, they may be identical from a dynamic point of view: epigenesis may in both cases be the cause of the acquisition of these new phenotypes. This was highlighted by the identity of (...) formal graphs modelling these networks. A mathematical framework based on formal methods from computer science was defined and implemented with a software environment. It allows an easy and rigorous validation and certification of these models and of the experimental methods that can be proposed to falsify or validate the underlying hypothesis. (shrink)

The conviction, due to previous failures, that bacteriology and darwinism were incompatible, has postponed the application of molecular phylogenesis to bacteria. But once introduced, this new field has led to a profound revolution of this science. A stable classification of the bacteria is at last possible; a new domain, the Archae, as distant from the Bacteria as from the Eukarya, has been discovered; noncultivable new species can be identified from the environment. It may even be possible to unravel the pathway (...) of early evolution after the common ancestor. However, controversies on this subject are already disregarded by the new paradigm. (shrink)

De récents scandales clans l'industrie du médicament ou l'agro-alimentaire ont montré les risques d'un détournement de la recherche scientifique. L'objet de ce livre est de mieux comprendre les ressorts de la crise qui s'installe ainsi entre science et société et de proposer des solutions respectant aussi bien l'indépendance de la recherche que le besoin de démocratie, très largement à inventer au demeurant, dans les choix de politique scientifique. Il s'adresse aux scientifiques comme aux citoyens. Il analyse la manière dont le (...) capitalisme néolibéral tente de mettre la science et les techniques au service de la compétitivité et des profils. Il s'appuie sur les résistances à cette politique pour montrer que la démocratie scientifique ne se résume pas à la question des choix technologiques ou de la gestion des risques et ne concerne pas la seule communauté scientifique. Il veut ouvrir des pistes pour mettre la connaissance scientifique et le développement technique au service des besoins humains (y compris le besoin de connaissances), ce qui appelle de nouvelles formes d'investissement citoyen et de pluralisme scientifique. (shrink)

Ce livre part d'une question : pourquoi les gauches ne parviennent-elles pas à faire émerger un projet crédible, en dépit de l'urgence du besoin? Il repose sur urge conviction : un des (nombreux) obstacles réside dans le fait que l'on reste trop souvent sur le terrain de l'adversaire, en ne combattant pas explicitement la forme même de pensée sur laquelle s'appuie l'idéologie dominante et qui la conforte. A l'heure actuelle émerge, à partir des avancées scientifiques, une nouvelle forme de pensée, (...) profondément dialectique, la pensée du complexe, qui peut fournir une aide considérable à l'action politique émancipatrice et nourrir un renouvellement du rationalisme. (shrink)

The mechanisms by which bacteria adapt to changes in their environment involve transcriptional regulation in which a transcriptional regulator responds to signal(s) from the environment and regulates (positively or negatively) the expression of several genes or operons. Some of these regulators exert a positive feedback on their own expression. This is a necessary (although not sufficient) condition for the occurrence of multistationarity. One biological consequence of multistationarity may be epigenetic modifications, a hypothesis unusual to microbiologists, in spite of some well-known (...) epigenetic modifications in bacteria. We propose here that the occurrence of mucoidy in the opportunistic pathogen Pseudomonas aeruginosa, which is currently attributed to mutations only, may also be an epigenetic modification. A theoretical approach using a generalised logical analysis lends credit to this hypothesis and suggests experiments to ascertain it. (shrink)

The transformations undergone by research and science in the name of the so called "knowledge economy" cover the decisions of scientific policies and the "management" of research, and also the meaning of scientific activities (devoted to innovation) and even more fundamentally the very structure of the sciences (transformed to technosciences). The science that is contributing to capitalist competitiveness (and to the current economic crisis) is not the same as that which would be able to contribute "to the conception and democratic (...) carrying out of another form of globalization and another European project". However, this is not self-evident, and it needs to be thought about since it is not simply a matter of returning to the science of the 20th century that opened the way to technoscience. (shrink)