|Abstract Title:||Genomic and Transcriptomic analysis of a Deep-Ocean Alteromonas sp. with capacity for Methylmercury Detoxification|
|Presenter Name:||Carla Pereira-Garcia|
|Company/Institution:||Universidad Autonoma de Barcelona|
|Session:||Special Session - Meta-omic and geochemical approaches to linking microbial activity to biogeochemical mercury cycling|
|Day and Session:||Friday 29th July - Session One|
|Start Time:||06:00 UTC|
Abstract Information :
Methylmercury (MeHg) is one of the most worrisome pollutants in aquatic systems which bioaccumulates and biomagnifies in the marine food web, and a potent neurotoxicant in humans exposed to it through fish consumption. Its biological detoxification is mediated by the mer operon, which contains two genes, merB and merA, responsible for the demethylation of MeHg and the reduction of inorganic mercury, respectively.
While a lot of emphasis has been put into studying contaminated sites, little is known about the prokaryotes carrying this operon living in pristine environments such as the deep ocean. This study provides: the genome characterization of Alteromonas sp. ISS312, isolated from the bathypelagic at 4000 m depth in the South Atlantic Ocean during the Malaspina expedition and the transcriptomic comparison of two conditions, with and without MeHg.
Two culture conditions with our isolate (MeHg 5 æM and control) were used to obtain DNA and RNA at different stages of the growth curve. DNA and RNA extraction, sequencing, assembly and differential expression analysis were performed.
The exploration of Alteromonas sp. ISS312 genome revealed that it harbors 4 mer operons, three of them containing merA gene and two of them containing the merB. Moreover, the comparative transcriptomics analysis showed that these merA/merB genes are within the most expressed genes at different expression level over time. Other genes of our interest, involve in the the biosynthesis of CoA, methane metabolism, biofilm formation, chemostaxis and flagellar development, are also affected. Our results also support the hypothesis that the mer operon is highly dynamic between distant related genomes, probably due to horizontal gene transference mediated by mobile elements such as transposases.