| L | M | M | J | V | S | D |
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | ||||
| 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 11 | 12 | 13 | 14 | 15 | 16 | 17 |
| 18 | 19 | 20 | 21 | 22 | 23 | 24 |
| 25 | 26 | 27 | 28 | 29 | 30 | 31 |
In this talk I will present two studies of collective behavior observed in animal groups. In the first one, we studied the spontaneous and intermittent collective displacements observed in small groups of sheep and studied particularly the role of leader, who was not always the same individual. We investigated the benefits of such 'democratic' leadership and found scenarios where individuals of the group might benefit from this strategy. In the second study I will present experimental data acquired in Teapa, Mexico, where groups of sulphur mollies evolved to live in sulphidic springs with high concentration of hydrogen sulphide. In this system, we studied the highly conspicuous, repetitive, and rhythmic collective dive cascades produced by many thousands of these fish that resemble neuronal avalanches observed in brain tissue at criticality. Together with the results of an agent-based model of the system, we explored the functionality of this behaviour for the fish by using machine learning algorithms and showed that the best-fitting model allows information about external perturbations – such as predator attacks – to propagate most effectively through the shoal.
Le transfert horizontal de gènes est un facteur majeur de l’évolution et de l’adaptation bactériennes, qui leur permet une acquisition rapide de nouveaux caractères comme la résistance aux antibiotiques. Staphylococcus aureus (SA) possède une grande variété de gènes de résistance aux antibiotiques (GRA). Sa capacité à acquérir des GRA est étroitement associée à la grande proportion d’éléments génétiques mobiles (EGM) présents dans son génome (entre 15 à 20%) et à son aptitude à échanger du matériel génétique avec son environnement. À ce jour, peu de données sont disponibles sur la diversité des EGM porteurs de GRA chez les SA, et leur impact sur la dissémination de l’antibiorésistance est peu documenté. Une analyse in silico de 9054 génomes de SA disponibles dans les bases de données NCBI et remplissant des critères de qualité d’assemblage a été réalisée. Une cartographie exhaustive des associations entre EGM, GRA et hôtes a été établie en utilisant les outils ResFinder, RGI- CARD et MEFinder. En parallèle, une analyse in vitro de 267 SA isolés d’animaux au travers du Résapath [1] entre 2010 et 2021 et porteurs de GRA a été menée. Leurs plasmides ont été caractérisés par PFGE
Neutrophils are part of the major players of the innate immune response upon pathogen infection. Among other antimicrobial functions, neutrophils have a unique ability to produce and release oxidizing antimicrobial compounds mediated by myeloperoxidases (MPO), including hypochlorous acid (HOCl) and N-chlorotaurine (N-ChT). Focusing on the human pathogen Salmonella enterica serovar Typhimurium, our laboratory recently unravelled unprecedent defense mechanism against MPO-derived oxidants. We notably established a link between MPO-derived toxicity and the Salmonella’s envelope stress response. These findings will be a central topic of discussion in my seminar.
Résumé:
Most of us are aware of the hive mind—the power of bees as an amazing collective. But do we know how uniquely intelligent bees are as individuals? I argue that they have remarkable navigational abilities, can recognize not just flowers but also human faces, exhibit basic emotions, count, use simple tools, solve problems, and learn by observing others. They may even possess consciousness. I illustrate how bee brains are unparalleled in the animal kingdom in terms of how much computing power is packed into their tiny nervous systems. I examine the psychological differences between bees and the ethical dilemmas that arise in conservation and laboratory settings because bees might feel and think.
Nous suivre 
Université Paul Sabatier
118 Route de Narbonne
31062 TOULOUSE Cedex
France
05 61 33 58 00
