Online Seminar Series – 22 Apr 2021

 

 

15:00 WET / 16:00 CET  

Philipp Engel (UNIL)

Affiliation: Department of Fundamental Microbiology, University of Lausanne, Switzerland

Title: Understanding microbiomes – Insights from bees and their gut symbionts

Abstract: Specialized bacterial communities colonize the animal gut and impact health and disease of the host in manifold ways. However, the complex composition of these communities presents a veritable challenge for disentangling gut microbiota functions, to assess their diversity, or to understand the ecology and evolution of individual community members. In my lab, we study the gut microbiota of social bees. Honey bees, bumble bees, and stingless bees harbor simple, yet highly specialized, bacterial communities in their guts. These bacteria are experimentally amenable and gnotobiotic bee models have been established, which makes bees great models for addressing current questions of gut microbiota research. We combine experimental and genomic approaches to assess how diversity has evolved and is maintained in these communities, and which functions are carried out by which community member. In my talk, I will give an overview on bee microbiome research and summarize recent projects we have carried out in our lab.

 

15:30 WET / 16:30 CET

Luís Teixeira (FCG-IGC)

Affiliation:  Host-Microorganism Interactions, Instituto Gulbenkian de Ciência, Portugal

Title: Functional genomics of the endosymbiont Wolbachia

Abstract: Wolbachia is an intracellular, maternally transmitted bacterium that is present in approximately 40% of terrestrial arthropod species. This endosymbiont is often a reproductive parasite but can also provide fitness benefits to its hosts. For instance, the Wolbachia in Drosophila melanogaster, wMel, provides protection against viruses.  This protective effect is currently being applied to fight arboviruses transmission by releasing Wolbachia-transinfected mosquitoes. Titre regulation is a crucial aspect of Wolbachia biology. Higher titres can lead to stronger phenotypes and fidelity of transmission but can have a cost to the host. Since Wolbachia is maternally transmitted, its fitness depends on host fitness, and, therefore, its cost to the host needs to be controlled. Understanding this and other aspects of Wolbachia biology has been hampered by the lack of genetic tools. Here we developed a new forward genetic screen to identify Wolbachia over-proliferative mutant variants. We characterized in detail the phenotype of these two new mutants, wMelPop2 and wMelOctoless. Through genome sequencing we identified the genetic bases of these phenotypes, and expand on the understanding of the role of the Octomom genomic region in the control of Wolbachia proliferation.  Altogether, we demonstrate the feasibility of a novel and unbiased experimental approach to study Wolbachia biology, which can be further adapted to characterize other genetically intractable bacterial endosymbionts.

 

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