Latest addition : 28 February 2012.
The activity of the team revolves around a variety of subjects that require knowledge of a wealth of methods and technologies.
Composition of the Molecular Transport and Signalling team
To survive, bacteria have to exchange molecules with their environment. As they have evolved, bacteria have developed extremely smart systems to import and export molecules through their membranes. Pathogenic bacteria use these systems to inject toxic molecules in their cell targets. Such systems are therefore associated to virulence making of them interesting targets in the fight against bacterial infections.
Lactococcus lactis is a Gram+ bacterium extensively used in the dairy industry for the manufacture of fermented products and cheese. Infection of L. lactis by bacteriophages is therefore an economical issue, since these phages are ubiquitous in the environment. Several hundreds of phages infecting L. lactis belong to the Siphoviridae family, characterised by possessing a double-stranded DNA genome and a long, non-contractile tail. We are studying the anchoring strategy of these phages to their host, particularly the structure of the baseplate proteins. With this aim, we use X-ray crystallography and cryo-electron microscopy.
Archaeal viruses are known since the early 1970s. However, only recently they have drawn strong interest. Archaeal viruses are particularly interesting from an evolutionary point of view, because their hosts have characteristics that make them resemble both bacteria and eukaryotes. Cells from archaea are closely similar to those from bacteria; therefore, one would expect that archaeal viruses would be similar to bacteriophages. This is actually the case for most viruses infecting euryarchaeota but not for those of the crenarchaeota. In staggering contrast to their evolutionary interest, the biology of crenarchaeal viruses remains largely unknown. This situation mirrors the fact that between 50% and 90% of the open reading frames (ORFs) predicted in the genomes of these viruses have no associated functional annotation.
Development studies based on animal models, together with the annotation of metazoan genomes have shown that a relatively small number of gene families encoding structurally related proteins underlie the amazing diversity of animal body plans. This observation raises the problem of diversity: how can a single molecule reach functional diversity and induce different biological outputs? Furthermore, most regulatory molecules share structural/functional motifs, which brings in the issue of specificity: how can molecules sharing similar biochemical properties nevertheless control specific developmental programs?
Insects, and in particular noctuelles, are wonderful tools for studying the molecular aspects of olfaction, as many of their mandatory life-functions depend on olfaction and the olfaction-dedicated organs, the antennae, are large easily accessible. Small proteins (12-18 kDa) able to bind odorant volatile molecules have been identified in the antennal lymph.