Evolutionary exploration of a bacterial LPS genotype to phenotype map with phages

The evolution of bacterial resistance-to-phage strategies, and the mechanisms by which phages adapt to overcome these strategies, are usually studied via evolution experiments in which phages are added to sensitive bacteria and allowed to co-evolve. While this top-down approach has improved our understanding of co-evolutionary dynamics, it underestimates the diversity of available evolutionary pathways. In this thesis work, I propose an evolutionary bottom-up approach to study the natural lipopolysaccharide (LPS) structure diversity in resistant E. coli C strains and the corresponding ΦX174 adaptation process. I first investigated the mutational causes responsible for ΦX174-resistance using whole-genome sequencing. All phage-resistant mutants carry at least one mutation in genes linked to core LPS biosynthesis, assembly or regulation. Based on which genes are mutated and the current knowledge of LPS biology, I predicted that these bacterial strains collectively produce eight different LPS structures. Then, I used serial transfer experiments to evolve ΦX174 against each resistant mutant and determined the set of mutations required to overcome resistance. ΦX174 overcomes LPS-based resistance via mutations in only two genes: the F gene involved in host recognition and the H gene involved in DNA injection. Finally, I tested my predicted LPS genotype to phenotype maps using multiple phage infection assays to qualitatively determine the host range of each evolved phage. I showed that my evolved ΦX174 strains are great biosensor tools that can discriminate different E. coli C resistant strains. I also demonstrated that the LPS diversity is much greater than predicted. Instead of eight LPS structures, my phage analysis suggests that there are at least 14 distinct LPS phenotypes. My approach allows a deeper understanding of bacteria-phage interactions essential for developing efficient phage therapies in the future

Comparison of damaging behavior of oxide scales grown on austenitic stainless steels using tensile test and cyclic thermogravimetry

Two austenitic stainless steels, AISI 304L and AISI 303, were submitted to cyclic oxidation and to staticmechanical loading after isothermal oxidation at 1000◦C. Alloy 303 contains ten times more S than 304Land some Mn addition. During the steel process, it formed manganese sulfides that lead to the formationof a less resistant oxide scale. Both alloys showed similar behavior during thermal cycling but breakawayoxidation and intensive spallation occurred much sooner for alloy 303 than for alloy 304L. A correlationcould be drawn between tensile test on preoxidized samples, isothermal and cyclic oxidation

16. Gourinat (Jean-Baptiste), Les stoïciens et l'âme

Romeyer Dherbey G. 16. Gourinat (Jean-Baptiste), Les stoïciens et l'âme. In: Revue des Études Grecques, tome 110, Juillet-décembre 1997. pp. 664-666

Gourinat (J. B.), Les Stoïciens et l'âme, 1996. (Philosophie ; 75)

Romeyer Dherbey Gilbert. Gourinat (J. B.), Les Stoïciens et l'âme, 1996. (Philosophie ; 75). In: Revue des Études Anciennes. Tome 99, 1997, n°3-4. Mélanges dédiés à la mémoire de J. Coupry. p. 574

Une didactique des langues étrangères ciblant l’acquisition des formes phonologiques peut sans doute être profitable à tous les élèves

The comparison of the effect of two targeted teaching methods on the acquisition of phonological representations of French as a foreign language by three dyslexic pupils showed that these pupils were able to benefit from targeted teaching, even for the acquisition of procedural representations. Targeted implicit teaching taught in an action-oriented communicative method enabled the observed dyslexic pupils to improve their ability to discriminate and maintain verbal information in working memory, as well as their receptive vocabulary, in the same way as focus-form explicit teaching. However, explicit instruction was more conducive to learning pronunciation for the dyslexic pupils observed

Gourinat (J. B.), Les Stoïciens et l'âme, 1996. (Philosophie ; 75)

Romeyer Dherbey Gilbert. Gourinat (J. B.), Les Stoïciens et l'âme, 1996. (Philosophie ; 75). In: Revue des Études Anciennes. Tome 99, 1997, n°3-4. Mélanges dédiés à la mémoire de J. Coupry. p. 574

L'apprentissage des correspondances phonème graphème en FLE

How are phoneme to grapheme correspondences in FLE learnt by German speaking teenagers in a school context

16. Gourinat (Jean-Baptiste), Les stoïciens et l'âme

Romeyer Dherbey G. 16. Gourinat (Jean-Baptiste), Les stoïciens et l'âme. In: Revue des Études Grecques, tome 110, Juillet-décembre 1997. pp. 664-666