Assessing molecular interactions at the surface of living cells is a challenge in biophysics, cell biology and microbiology. We aim at initiating a collaboration between biophysicists, microbiologists and biologists from Toulouse and Trondheim in order to address this question. The field of expertise covered by the project partners includes deep knowledge of yeast cells and genetic manipulation of these, microbiology, and microbial biotechnology, as well as AFM and OT based force spectroscopy and investigation of mechanical properties of cells. In this collaboration we will elucidate the interaction capacities of microorganisms using AFM and OT. To this aim we have identified three relevant systems that will be explored. These include the interactions of mycotoxins with the yeast cell wall, bacteria ? mucus interactions as well as antibodies interacting with peptides on cell surfaces. The studies will be performed as collaborative effort between the French and Norwegian laboratories involved. Regular contact between the researchers and students involved in the project will be assured also in the periods where the researchers involved are present in their respective laboratories in Toulouse and in Trondheim. However, research visits by the Norwegian researchers to France and vice versa are judged as essential for optimal output of the collaboration. The scientists involved share a strong common interest for the topics and the instrumentation described in the application. They are also engaged in collaborations with biologists working on different models such as bacterial interactions with fish skin, intestinal mucus, yeast cell adhesion in food and wine industry or in the medical domain. All these researchers are confronted with the same issue: understanding the molecular interactions occurring at the surface of living cells. Hence, building a strong collaboration through this project sets the basis for a wider research perspective, i.e. a future EU project.