Microbiota Seminars

Our group regularly invites researchers who work on the microbiota.

Sponge microbiome

  • June 14, 2017, 2:30pm, Rheumatology conference room, Nadine Cerf-Bensussan (Laboratory of Intestinal Immunity, Institut Imagine, U. Paris-Descartes, France)

 "Host-microbiota interactions across the gut immune system: an evolutionary trade-off"

Abstract:

To cope with the complex microbial community that settles in the distal part of our intestine after birth, hosts have evolved a spectrum of complementary innate and adaptive immune mechanisms. This highly dynamic barrier is programmed ante-natally but fully develops only after birth in response to signals from the microbiota. To analyse the host-microbiota dialogue, we have chosen to address two main questions.
1- What are the respective roles of individual bacterium in driving the maturation of the gut barrier? Do they exert distinctive or redundant effects? Our studies in gnotobiotic mice have unexpectedly revealed that a restricted number of host-specific bacterial species, the prototype of which is Segmented Filamentous bacterium (SFB), are necessary for the complete maturation of the gut immune barrier. We will discuss how the ecological niche of SFB differs from that of other members of the microbiota, and enables SFB to deliver signals, which instruct the development of gut innate and adaptive immune responses and help establishing a state of physiological inflammation, which protects the host against pathogens.
2- What are the key mechanisms evolved by the hosts, to cope with the microbiota? Our current work led in children affected by monogenic disorders causing early onset intestinal inflammation provides interesting insight on conserved genetic mechanisms to maintain mutualistic relationships with the microbiota.

  • March 22, 2017, 2:30pm, Rheumatology conference room, Silvia Bulgheresi (University of Vienna, Austria, Department of Ecogenomics & Systems Biology)

 "Dressed to Cooperate – Marine Nematode-Bacterium Symbioses"

Abstract:

Up to now, the study of bacterial reproduction focused on model organisms. On the other hand, cell biological research on environmental bacteria – including those thriving on animal surfaces – are scarce. Marine nematodes engage in binary associations with chemosynthetic Gammaproteobacteria. The spatial dispositions of the bacterial symbionts on the surface of their cognate hosts is species-specific, invariable, and mediated by extraordinary reproductive strategies: the rod-shaped Laxus oneistus and Robbea hypermnestra symbionts widen and set their septation planes longitudinally (Leisch et al., 2012, 2016). The Eubostrichus fertilis symbiont can divide at virtually every length between 4 and 45 µm resulting in an unprecedented 10-fold length variation within the same cell population. Finally, the up to 120 µm-long E. dianeae symbiont is the longest bacteria known to divide by symmetric transverse fission (Pende et al., 2014). We want to determine the molecular and cellular mechanisms underlying the anomalous reproductive strategies of animal-attached bacteria and their ecological significance.

  • February 8, 2017, 3:30pm, Rheumatology conference room, Samuel Alizon (MIVEGEC, Montpellier, France)

"Within-host ecology of sexually-transmitted infections: the case of human papillomaviruses"

  • December 19, 2016, 2:30pm, Rheumatology conference room, Philippe Sansonetti (Institut Pasteur & Collège de France)

"Humans and their microbiota: an (almost) perfect symbiosis"

PDF of the presentation: Humanmicrobiota

  • June 23, 2016, 11am, Rheumatology conference room, Jan Pieter Konsman (Institute for Integrative and Cognitive Neuroscience in Aquitaine, CNRS & Univ. Bordeaux)

A Gut Feeling Bugging the Immunologist? The possibility of a direct microbe-gut-brain axis

PDF of the presentation: BugGutBrain

Gut-brain axis

  • May 26, 2016, 1:30pm, Salle de conférence du Centre de génomique fonctionnelle (Map Génomique Fonctionnelle), Thomas Bosch (Zoologisches Institut, University of Kiel, Germany; Head of DFG project "Origin and Function of Metaorganisms”)

"The Holobiont Imperative: Novel Perspectives for Biology and Medicine”

Abstract:

For a long time, the main purpose of host-associated microbiology was to study pathogenic bacteria and infectious disease; the potential benefit of good bacteria remained unrecognized. In the last 10 years, biology has made revolutionary advances from century-old debates about the relative importance of non-pathogenic bacteria. Today we know that individuals are not solitary, homogenous entities but consist of complex communities of many species that likely evolved during a billion years of coexistence. Holobionts (hosts and their microbes) and hologenomes (all genomes of the holobiont) are multipartite entities that result from ecological, evolutionary and genetic processes. I propose, therefore, that the health of animals, including humans, is fundamental multi-organismal; that any disturbance within the complex community of host and microbial cells has drastic consequences for the wellbeing of the individual member of this association; and that the microbiome can be viewed as an organ of the host. This newfound awareness of the dependency of phenotypes on other species and environmental conditions presents additional layers of complexity for evolutionary theory and raises many questions that are being addressed by new research programmes.

Bosch_Thomas_2015

 

  • April 26, 2016: Muriel Thomas (Micalis, INRA Jouy-en-Josas, PI “Epithelium and microbiota” team, France)

"The contribution of the microbiota to gut and lung physiology"

Full PDF presentation: Thomas Muriel_Bordeaux talk

Abstract:

The microbiota inhabiting the gut is a main actor of digestive physio-pathology, and we have contributed to show that the bacterial colonization is critical for a proper homeostasis of intestinal epithelial cells (1-5). Our data show how microbiota, specifically the primo-colonizing bacteria arriving early after birth, may impact genuine features of epithelium by considering its morphology, secretive, absorptive and storage functions. After decades of research about gut microbiota, it is well established that bacterial families strongly impact gut immunity and physiology in a specific manner.

In 2010, the lung microbiota has been described, disturbing the ancient dogma based on the absence of microbes in healthy lungs. The lung bacterial community involves mainly Pseudomonas, Streptococcus, Prevotella, Fusobacteria, and Veillonella in healthy human lungs and the bacterial load and composition are changing along respiratory pathologies. Thus, based on our expertise in gut, we have recently developed a new area of research in our team to study the impact of lung microbiota on lung physiology. In this context, we focused our study on the effect of lung microbiota in the susceptibility to asthma (model using the sensitization and a challenge with House Dust Mite). We have established that a microbial education of the mucosal microenvironment occurs in the lung and that appropriate bacterial lung stimuli during early life are critical for allergic asthma susceptibility. Our study brings evidence that there is a reciprocal influence between lung bacteria and asthma in neonatal mice, highlighting the bacterial impact on respiratory pathophysiology.
 
1.              Rul, F., Ben-Yahia, L., Chegdani, F., Wrzosek, L., Thomas, S., Noordine, M. L., Gitton, C., Cherbuy, C., Langella, P., and Thomas, M. (2011) Impact of the metabolic activity of Streptococcus thermophilus on the colon epithelium of gnotobiotic rats. J Biol Chem 286, 10288-10296
2.              Wrzosek, L., Miquel, S., Noordine, M. L., Bouet, S., Joncquel Chevalier-Curt, M., Robert, V., Philippe, C., Bridonneau, C., Cherbuy, C., Robbe-Masselot, C., Langella, P., and Thomas, M. (2013) Bacteroides thetaiotaomicron and Faecalibacterium prausnitzii influence the production of mucus glycans and the development of goblet cells in the colonic epithelium of a gnotobiotic model rodent. BMC Biol 11, 61
3.              Deschemin, J. C., Noordine, M. L., Remot, A., Willemetz, A., Afif, C., Canonne-Hergaux, F., Langella, P., Karim, Z., Vaulont, S., Nicolas, G and Thomas, M. (2016) The microbiota shifts the iron sensing of intestinal cells. FASEB J. Jan;30(1):252-61.
4.              Miquel, S., Leclerc, M., Martin, R., Chain, F., Lenoir, M., Raguideau, S., Hudault, S., Bridonneau, C., Northen, T., Bowen, B., Bermudez-Humaran, L. G., Sokol, H., Thomas, M., and Langella, P. (2015) Identification of metabolic signatures linked to anti-inflammatory effects of Faecalibacterium prausnitzii. MBio 6
5.              Tomas, J., Reygner, J., Mayeur, C., Ducroc, R., Bouet, S., Bridonneau, C., Cavin, J. B., Thomas, M., Langella, P., and Cherbuy, C. (2015) Early colonizing Escherichia coli elicits remodeling of rat colonic epithelium shifting toward a new homeostatic state. ISME J 9, 46-58
 
(2:30pm, Salle de conférence de la Plateforme de Génomique Fonctionnelle)

Muriel-Thomas

 

 

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