Potential Microbial Detoxifiers of MeHg in Barcelona City Continental Shelf

Trabajo final presentado por Marina Pérez García para el Máster en Microbiología Avanzada de la Universitat de Barcelona (UB), realizado bajo la dirección de la Dra. Silvia González Acinas y de la Dra. Andrea García Bravo del Institut de Ciències del Mar (ICM-CSIC).-- 28 pages, 12 figures, 8 tablesMercury specially in the form of Methylmercury (MeHg) is a big concern because affects human and wildlife health and accumulates and biomagnified in the aquatics systems through the food chain. Some Bacteria and Archaea have evolved resistance mechanisms to mercury compounds, this resistance is encoded in the mer operon. So, the microorganisms that have merA and merB genes can completely transform the neurotoxic form of MeHg in the volatile form of mercury. Despite the persistence of mercury there is no information about the mercury detoxification processes in Barcelona continental shelf. Therefore, the aim of this study is to detect the presence of merA and merB in past (1987 and 2008) and present (from two months April and May 2018) sediment samples from the Barcelona continental shelf. For this task we performed DNA and RNA extractions and amplification of 16S PCR to detect the presence of microbial DNA. Since there is not currently specific primers for merA and merB genes targeting microbial taxa from contaminated sediment microorganisms, we have designed a pool of 10 specific primers for 5 microorganisms that could potentially be in the sediments and present these genes. Of those, we have detected the possible presence of merB genes related to Rhodococcus, Pseudomonas and Desulfovibrio in the sediments samples from fresh (2018) and 2008 samples. Future validation by sequencing those merB PCR amplicons would be done in a next step as well as the attempt to isolate those microorganisms in pure culturePeer Reviewe