Seminar Series – 20 May
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SymbNET Online Seminar Series
Monthly seminars on host-microbe symbiosis, genomics, and metabolomics, with two talks from SymbNET researchers.
The seminars are open and free to all, but registration is required.
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15:00 WEST / 16:00 CEST
Affiliation: Evol Ecol and genetics, Kiel University and Max-Planck Institute for Evolutionary Biology, Germany
Title: Evolution of C. elegans – microbe interactions
Abstract: Microbial interactors are key determinants of the biology of any organism. The model nematode C. elegans provides an ideal host system to study these interactions, because of the large variety of tools and the enormous biological database available for this worm. I here provide an overview of our current understanding of the worm’s interaction with naturally associated microbes. I will focus on the worm’s native microbiome and the evolutionary interactions between C. elegans and some of the bacteria. Our work revealed an influence of the microbes on metabolism, developmental processes, reproduction, and especially immune defense. We further identified the bacterial traits and underlying genes, which are essential for the bacteria’s adaptation to the host environment. Our findings provide new insights into the evolution of host-microbe associations and highlight the nematode C. elegans as a tractable model system to dissect the genetics and dynamics of these interactions.
15:30 WEST / 16:30 CEST
Affiliation: Bacterial Signalling, Instituto Gulbenkian de Ciência, Portugal
Title: Manipulation of Bacterial Quorum Sensing in the Mammalian Gut Microbiota.
Abstract: The mammalian gastrointestinal tract harbours a diverse and complex resident bacterial community composed of hundreds of species, which interact with each other and the host, and which can influence many processes required for optimal host health. We asked if bacterial cell-cell communication, mediated by quorum sensing, could shape the species interactions occurring in the highly dense and competitive gut environment. Quorum sensing is a cell-cell signalling process used by many different bacteria to regulate bacterial group behaviours. We have established a mouse model to manipulate quorum sensing mediated by the signal AI-2, directly in the mouse gut. Our work provided the first evidence that the quorum sensing signal AI-2, which foster inters-species communication, can influence the species composition of the major bacteria phyla of the gut microbiota. Moreover, our results indicate that forcing the microbiota to committee to quorum sensing during antibiotic-induced microbiota imbalances (dysbiosis) can promote recovery of gut homeostasis. To identify the molecular basis of AI-2 regulated microbiota responses, we used an ecological based mathematical model to model microbiota dynamics during dysbiosis and infer AI-2-mediated species interactions, which were then tested with gene expression studies. Our results indicate that AI-2 inhibits the expansion of Bacteroides vulgatus, the major pathobiont in antibiotic induced dysbiosis. Our working model predicts that AI-2 inhibits pathobiont expansion by inhibiting a nutrient sharing network between B. vulgatus and the closely related microbiota member Bacteroides ovatus.
SymbNET Seminars