Adrien Lapointe

Research Project B4: Biofilms, a lifestyle that defies changes?

I am a doctoral research student specialized in aquatic microbiology. I am interested in the physiological and chemical adaptations of aquatic microorganisms when impacted by natural or anthropogenic environmental modifications. I did my Master 2 internship in aquatic ecotoxicology at the ISMER institute (Quebec, Canada), studying the impact of pesticides on Nordic marine bacteria.

My PhD project in Konstanz University (2017-2020): “Biofilms, a lifestyle that defies changes”?

Epilithic photoautotrophic biofilms represent a huge part of the primary production in the littoral of Lake Konstanz. Biofilms consist in defined communities of phototrophic algae and heterotrophic bacteria. Recent studies have shown that some bacteria could induce the production of carbohydrates and the biofilm formation of benthic diatoms, while bacteria feed on these carbohydrates. This tight interdependence of the organisms in the biofilms raises questions about the benefits of such communities with regard to resilience against environmental changes. Therefore, this project focus on the impact of environmental changes (nutrients concentration, light intensity, temperature) on the bacteria-diatom interactions within a photoautotrophic biofilm. To study the chemical and physiological responses of this interkingdom communication, we will use the model system Dyoadobacter S32 and A. minutissimum. This model system will be cultured in biofilm incubators with continuous medium exchange to simulate the growth condition in the shallow, littoral zone of aquatic habitats. We will use proteomic methods to investigate the role of bacteria on diatom protein expression, regarding the resilience of the biofilm. Furthermore, biofilm samples of Lake Konstanz will be cultured in biofilm incubators to verify the effects of a selecting impact factor. The aim of this project is to identify bioactive compound(s) involved in shaping the interactions between bacteria and algae, in different growth conditions under environmental changes.

Key words: Photoautotrophic biofilm, bacteria inducing biofilm, bacteria-algae interactions, environmental changes, resilience, extracellular proteomics, metabolomics, LC-HR-MS/MS, GC-MS, HPLC, bioinformatics analyses, bioactive compounds.