General Information
A 36 month position for an experimentalist postdoc is available in the team of Simonetta Gribaldo at the Institut Pasteur, Paris (https://research.pasteur.fr/en/team/group-simonetta-gribaldo/).
In our group, we study the evolution of microorganisms and their main cellular processes by using a combination of in silico and wet-lab approaches. We have recently addressed one of the most important transitions in the history of Bacteria: that between cell envelopes with one membrane (monoderm) or two membranes (diderm). We showed that the ancestor of all Bacteria was already a complex diderm and that monoderms arose multiple times independently through loss of the outer membrane. To understand this major transition, we have developed a new experimental model, the diderm Firmicute Veillonella parvula (Negativicutes), an important anaerobic member of the human microbiome. A large range of protocols and genetic tools are now available in our lab to manipulate this bacterium and characterize its envelope. We have recently managed to obtain a V. parvula mutant where the outer membrane is highly destabilized, opening multiple possibilities to study the diderm-to-monoderm transition in the lab.
Project Description
The hired postdoc will have three main aims:
- Take advantage of recently acquired TnSeq and experimental evolution data to design genetic constraints and selection pressures that will favor outer membrane loss during further cycles of experimental evolution.
- Develop a bespoke genetic platform able to generate inducible genomic deletions, which can be used to guide outer membrane loss.
- Phenotypically characterize the mutants and evolved strains to understand the mechanism bacteria employ to respond to strong outer membrane destabilization or eventual loss.
Requested profile and application
The candidate should hold a PhD and have a strong background in bacterial genetics. Previous experience in bacterial envelopes, high-resolution microscopy, and/or manipulation of anaerobes is welcome although not necessary. A strong interest in microbial evolution and vivid scientific curiosity are essential qualities for this position. The postdoctoral fellow will enjoy a highly interdisciplinary and collaborative environment within a group of complementary expertise and subjects (experimental/bioinformatics; bacteria/archaea).
The position is immediately available. Ideal starting date could be January 2024. Benefits include comprehensive healthcare coverage for the fellow and their family, and 8 weeks paid annual leave. The Institut Pasteur is in the center of Paris, it has multiple state of-the-art facilities and constitutes a vibrant research community with 13 Departments across the Biology/Physics/Biomedical fields.
Candidates should send a motivation letter including a brief statement of research experience, technical expertise and interest for the project, a full CV and list of publications and the contact detail of three referees to Simonetta Gribaldo (simonetta.gribaldo_at_pasteur.fr).
References:
- Antunes LS, Poppleton D, Klingl A, Criscuolo C, Dupuy B, Brochier-Armanet C, Beloin C, and Gribaldo S (2016) Phylogenomic analysis supports the ancestral presence of LPS outer membranes in the Firmicutes. eLife 2016;5:e14589.
- Taib N, Megrian D, Witwinowski J, Adam P, Poppleton D, Borrel G, Beloin C, Gribaldo S (2020) Genome wide analysis of the Firmicutes illuminates the Gram-negative/Gram-positive transition. Nat Ecol Evol (12):1661-1672.
- Megrian D, Taib N, Witwinowski J, Beloin C, Gribaldo S (2020) One or two membranes? Diderm Firmicutes challenge the Gram-positive/Gram-negative divide. Mol Microbiol 03;113(3):659-671.
- Witwinowski J, Sartori-Rupp A, Taib N, Pende N, Tham TN, Poppleton D, Ghigo JM, Beloin C, Gribaldo S (2022) An ancient divide in outer membrane tethering systems in Bacteria suggests a mechanism for the diderm-to-monoderm transition. Nat Microbiol 7, 411–422.