MOLECULAR AND CELL BIOLOGY OF MICROORGANISMS
Spirydon Agathos, Françoise Foury, Michel Ghislain, Bernard Hallet, Pascal Hols, Jacques Mahillon, and Pierre Morsomme
Genome plasticity
Bacteria
B. Hallet, P. Hols, and J. Mahillon
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Genome flexibility and horizontal gene transfer mechanisms play a central role in bacterial adaptive strategies, virulence, and evolution.
In this area, we have focused our activities on the characterization of mobile genetic elements (mainly transposons, plasmids and bacteriophages) and the study of key processes in horizontal gene transfer (mainly transposition, site-specific recombination, conjugation, and competence) in Gram-positive bacteria. Biochemical and post-genomics (in silico genomics, functional genomics, and trancriptomics) approaches are currently used for these investigations.
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Yeast
F. Foury
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- Mitochondrial DNA (mtDNA), which encodes a small number of essential proteins of the respiratory complexes, coud display a high level of genome variability (large accumulation of mutations, multiple deletions, depletion). The Plog DNA polymerase plays a crucial role in the fidelity and stability of the mtDNA. The loss of the Plog proofreading activity increases the mtDNA mutation rate and is responsible of the so-called Polg disorders in humans.
In this research topic, we are using the yeast Saccharomyces cerevisiae as a model organism to understand the molecular bases of these mitochondrial diseases.
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Metabolic pathways
Bacteria
P. Hols, B. Hallet, and S. Agathos
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In this area, we study the carbon metabolism of homofermentative lactic actid bacteria (Gram-positive, e.g. lactococci, lactobacilli) and the degradation of persistent polycyclic aromatic hydrocarbons (PAH) by Sphingomonas sp. with a particular emphasis on key enzymes of these pathways. More specifically, DNA microarrays are used to investigate the functional role and the transcriptional regulation of these pathways in response to environmental conditions.
Additionally, we investigate the mechanisms that link the cell wall assembly (peptidoglycan and teichoic acids), morphogenesis, and cell cycle in two morphologically distinct species (ovococcus, rod) of homofermentative lactic actid bacteria.
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Yeast
M. Ghislain, P. Morsomme, and F. Foury
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The yeast Saccharomyces cerevisiae is used as a model to investigate three basic metabolic processes:
Membrane trafficking and its function in membrane protein sublocalization.
Membrane traffiking is essential for cell compartmentalization, homeostasis, differentiation, and intra- and inter-cellular communication. In this project, we study the molecular mechanisms that trigger the transport and the targeting of yeast Sna proteins from the endoplasmic reticulum (ER) to their final destination.
Degradation of membrane proteins by the ubiquitin-proteasome.
Proteins destined for the secretory pathway are translocated into the ER. Newly synthesized proteins that have defect in polypeptide folding or subunit assembly are recognized by quality control systems and eliminated by the 26S proteasome. Our project is to investigate how the mutated proteins are handled by known ER quality control and trafficking pathways.
Biosynthesis of iron-sulfur clusters.
The biosynthesis of iron-sulfur clusters relies on frataxin, a small acidic protein localized in mitochondria. We investigate the role played by frataxin in the biosynthesis of iron-sulfur clusters using genetics and molecular biology approaches. |
Biotechnological applications
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Mobile genetics elements as a tool box for DNA manipulation and mutagenesis (B. Hallet and J. Mahillon)
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Mobile genetics elements for molecular typing of food pathogens (J. Mahillon)
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Modified lactic acid bacteria (GMO and non-GMO) for the medical and agro-food sector (P. Hols)
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Improved processes of bioremediation of contaminated environments using modified or selected bacteria (S. Agathos)
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Yeast as an eukaryotic model for human deseases-perspectives in drug development (M. Ghislain, P. Morsomme, and F. Foury)
