Diversity of regulatory mechanisms in the C/N metabolism of the marine cyanobacteria Prochlorococcus and synechococcus
Year: 2015
Type: dissertation
Abstract: Marine picocyanobacteria are the most abundant photosynthetic organisms on \nEarth, with only two genera, Prochlorococcus (Johnson et al., 2006, Olson et al., \n1990, Partensky et al., 1999) and Synechococcus (Scanlan, 2003, Scanlan & West, \n2002) numerically dominating most oceanic waters. During this research project our \nmain goal was to study the diversity of the regulatory mechanisms in the C/N \nmetabolism of these cyanobacteria. Recent advances in the knowledge of nitrogen \nmetabolism of Prochlorococcus have shown that it has fine regulatory systems to \noptimize nitrogen assimilation (Rocap et al., 2003, García-Fernández et al., 2004, \nLindell et al., 2002). Thus, we have studied the role of 2-oxoglutarate in the control of \nthe C/N balance in order to check whether there exist differences with respect to other \nmodel cyanobacteria and among strains of Prochlorococcus. The comparative study \nperformed show that 2-oxoglutarate is the molecule responsible in Prochlorococcus \nto control the balance between carbon and nitrogen metabolism and there are \ndifferences among strains in sensing this metabolite. These results could be an \nexplanation for its adaptation to different ecological niches in the ocean. Besides, we \nwanted to know how Synechococcus is able to successfully coexist with \nProchlorococcus. For that, the hypothesis was that Synechococcus could be more \nefficient at the utilization of low concentration of nitrate. The results showed that \nwhen concentrations of nitrate in the range of nanomolar are present, the genes related \nwith the assimilation of that source are up-regulated in Synechococcus WH7803. \nTherefore, these facts suggest that the machinery is working at transcriptional level in \norder to uptake the nitrate. This could be an evolutionary advantage against \nProchlorococcus in the real field.
Author: María Agustina Domínguez-Martín
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2776666304