Lionel CLADIERE

In September 2008, I joined the Marine Glycobiology team within UMR 7139, headed by Dr Catherine Boyen (now UMR 8227, headed by Dr Catherine Leblanc), at the Station Biologique de Roscoff as a teacher-researcher. My subject was the development of genetic tools to transform the marine bacterium Zobellia galactanivorans, a bacterium isolated from red algae and capable of assimilating most algal polysaccharides. Initial studies were carried out using a multi-disciplinary approach, combining transcriptomics, comparative genomics, biochemistry and structural biology. The integration of the various results provided the basis for a model of the polysaccharide perception and utilization system within this bacterium. The development of genetic tools was a prerequisite for validating the in vivo biological functions of the candidate genes. To this end, collaboration was undertaken with Dr Eric Duchaud (INRA, Jouy-en-Josas) and Dr McBride (University of Wisconsin-Milwaukee, USA). This long-term work has been rewarded by the development of a directed mutagenesis technique enabling the functional study of genes of interest in Z. galactanivorans.

Armed with this new tool, my topic evolved towards the functional and enzymatic study of the alpha-glucan metabolic pathway in marine bacteria. Indeed, the metabolism of α-glucans in Z. galactanivorans remains uncharacterized. Another marine bacterium, the planctomycete Rhodopirellula baltica, has also shown interesting abilities to degrade algal polysaccharides. In particular, R. baltica can use starch as its sole carbon source. As with Z. galactanivorans, its genomic analysis has revealed numerous polysaccharidases and the annotation of enzymes involved in carbohydrate metabolism has been completely revised.
Recently, my work has shifted to the study of the structure/function of a SusD-type surface glycan-binding protein in the polysaccharide utilization system of the model marine flavobacterium Z. galactanivorans.
At the same time, as part of the ANR SulfASST project led by Dr F. Daligault in Nantes, work has begun on the functional characterization of arylsulfatases that can hydrolyse sulphate groups. Some of these families are not well understood at a functional level. I have been involved in this project from the outset, enabling me to co-supervise a doctoral student and obtain accreditation to supervise research.

Teaching activities
 My teaching activities are mostly in the domains of molecular biology, microbiology, biochemistry.
- lead organizer of the Microbiology module that is part of the blocks of course “Risks, dangers and analysis tools » option of the Food Safety Specialization ‘License Professionnelle’ (L3 pro, organizer S. Egée).
- co-organizer of the Biochemistry teaching for first- and second-year students on the Bachelor of Science degree in Life Sciences / dual specialization: biology and mathematics. My roles include examining admissions (selection of new students) and ensuring that the module content is kept up to date with relevant research topics.
- teaching Marine Bacterial Genomics and Structural Genomics courses for Masters level students, including practical classes in Prokaryote Genome Annotation for first year students.
- Having obtained the Programme of Investments for the Future (PIA) BLUE TRAIN, for the immediate and longer-term training in the development of the blue bio-economy, for five years I have been responsible for the ‘Licence professionelle Biotechnologies Marines valorisation des Bio-ressources’ (L3 pro) in which I teach marine microbiology and biochemistry of marine enzymes.
 
Poster presentation
Lionel Cladière, Mirjam Czjzek, Alexandra Jeudy, François Thomas. “Structure/function study of a SusD-like surface glycan binding protein in the Alginate Utilization System of the model marine flavobacterium Z. galactanivorans.” (2024) Carbohydrate Bioengineering Meeting 15, Ghent, Belgium
Lionel Cladière, Mirjam Czjzek, Alexandra Jeudy, François Thomas. “Structure/function study of a SusD-like surface glycan binding protein in the Alginate Utilization System of the model marine flavobacterium Z. galactanivorans.” (2024) Second International Conference on Marine Flavobacteria, Roscoff, France