Dolma Michellod

My research focus on a shallow water symbioses formed by gutless annelids and chemoautotrophic bacteria and their most unusual sterol profile and sterol synthesis ability. I also aim to describe the chemical landscape of deep-sea mussels living in close association with chemoautotrophic bacteria and determine the identity, distribution and potential functions of a metabolite group specific to association between deep-sea mussels and methane oxidizing symbionts.

My main research project focus on the unusual presence of sitosterol, a plant sterol, in shallow water gutless oligochaetes. The gutless oligochaetes sterol profile is dominated by a plant sterol and not as other animals by cholesterol. A combination of isotopic and omics analyses revealed unique sterol synthesis ability. Using heterologous gene expression and enzyme assay I investigate the activity of the key enzyme  involved in this unusual phytosterol biosynthetic pathway.

I use LC-MS/MS, molecular networking and MS2LDA analysis to study the lipid diversity and the impact the association with intracellular bacteria can have on the lipid composition of symbiotic and non-symbiotic mussel tissue. I combined those tools with metabolite imaging to characterize the structure, distribution and diversity of a specialized group of metabolites only present in the symbiotic organ and specific to methane oxidizers and deep-sea mussels association described for the first time by Geier et al. 2020.