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Impact of N-processes in animal-bacterium associations


Supervisor: Silvia Bulgheresi    

PhD student: Gabriela Paredes

Group: Environmental Cell Biology, Division of Archaea Biology and Ecogenomics, Department of Ecogenomics and Systems Biology






It is assumed that interactions between animals and bacteria may lead to increased N-cycle activity. However, any effort to prove this has been confronting with the overwhelming complexity of most animal-associated microbial communities. To test this hypothesis, we will study the rate of N fixation and denitrification in marine thiotrophic bacteria which form binary associations with nematodes and, based on available genome drafts, possess key genes for nitrogen fixation, denitrification and ammonia assimilation. Namely, by taking both single cell and omics approaches, we will will test whether N fixation by the symbiont can mediate N2 conversion into nematode biomass and if this process can be a source of N for the nematode by nanoSIMS, biochemical and stable isotope approaches. Secondly, we will test how symbiont N fixation and denitrification are coupled to S metabolism under various environmental conditions (e.g. oxic/anoxic) by –omics approaches. Thirdly, we will compare N metabolism of nematode symbionts collected from different habitats (e.g. mangrove sediment/back-reef sediment) or associated to different nematode hosts by transcriptomics and proteomics. 

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