Home > Research at LGC > BioSyM - Bioprocesses and Microbial Systems > Research topics > Theme 1 : Engineering for health: biofilms and mycotoxins

Theme 1 : Engineering for health: biofilms and mycotoxins

Contact : Christine Roques et Fatima El Garah

- This theme is organized around several health-related objectives. Studies include fundamental approaches of the behavior of microorganisms and their interactions with surfaces, the mechanisms of formation of biofilms, to applied approaches concerning the expression of biomolecules depending on the physiological state of the microorganism (planktonic, adherent, biofilm) and the loss of sensitivity to antimicrobials. The mycotoxins approach corresponds to the application of knowledge about these pathogenicity factors and their expression in terms of environmental biomarkers.

Processes supporting health care innovation

Understanding biofilm formation
The Laboratory’s expertise in terms of adhesion and formation of biofilm have led to the development of specific models allowing the study of the behavior of cells at different steps and of the 3D structure and of the extra-cellular matrix. The most notable studies concern i) the first demonstration of the Legionella pneumophila ability to generate monospecies biofilms (ANSES), ii) the usefulness of synthetic analogues of Quorum Sensing inductors (QS) in the in vitro control of Pseudomonas aeruginosa biofilm formation (VLM), iii) the association of QS and bioelectrochemistry. The original concept is the modification of the metabolic activity combining variation in the physiological status of the microorganism and by an electric field.

Legionella pneumophila biofilm - 3D reconstruction (confocal microscopy – Syto9®).

How to control biofilm formation
Learning about the behavior of bacteria at interfaces led to applied research. In this way, needs include the dispersion ofmicrobial biofilms but also biofilm formation in a specific location, depending on the aim. The applications considered concern health and the environment (fighting against nosocomial diseases [3], control of water networks, bioremediation) and biotechnology (synthesis of biomolecules, bio-batteries). Biofilm tool has been involved in numerous regional and national collaborations: behavior of bacteria in microfluidics [4], characterization of antimicrobial surface properties..

Biofilm and extracellular matrix (confocal microscopy – Syto9® and ConA).

Mycotoxins: Risk management, evaluation/validation of detoxification processes Characterization of the ochratoxin A mechanism of action. Mass spectrometry was used to identify a covalent DNA adduct providing absolute proof that ochratoxin A is a direct genotoxic carcinogen. We identified the metabolites responsible by “structure-activity relationship” studies. This enabled to define biomarkers not only for the follow up of exposed people/animals but also to validate means of detoxification. The work is based on international (Canada, UK, Czech Republic, Spain) and industrial collaborations and was supported by Region and Mycodiag projects. Risk evaluation linked to multi-contamination by mycotoxins: simultaneous exposure to several mycotoxins at doses considered acceptable led to toxic effects, questioning current legislation and stressing the need to find efficient means of detoxification. With this in mind processes using yeasts and lactic bacteria are being studied (Lesaffre and the Thai Biotechnology University).

Effect of an original analogue of homoserine lactones (C11) in association with antibiotics on the formation of Pseudomonas aeruginosa biofilm (T 48h; CIP, ciprofloxacine; TOB, tobramycine; CAZ, ceftazidime; COL, colistine)