Redox metabolism in Phaeodactylum tricornutum

ARIAS, DIEGO; GUERRERO, SERGIO A.; IGLESIAS, ALBERTO A.

Rosario – Santa Fe - Argentina

Congreso; SAIB - XLII Reunión Anual; 2006

Diatoms are important components of marine phytoplankton, being particularly relevant for geochemical cycling of minerals (mainly silica), and global carbon fixation. Diatoms are brown unicellular algae, thought to be responsible for around one-fifth of global primary productivity. Being such important players in the global ecosystem, their ecology and physiology have been the focus of research. The cellular redox state is a crucial mediator of multiple metabolic, signalling and transcriptional processes in cells. Also, protein thiols in the form of cysteine residues are key players in redox sensing and regulation. The thioredoxin (TRX) and glutathione (GSH) systems control cellular redox potential, keeping an intracellular state rich in reduced thiols. In this work, we present the molecular cloning of the genes coding for two TRXs, a PMSR (peptide methionine sulfoxide reductase) and a putative PrxQ (peroxiredoxin Q), all enzymes involved in redox metabolism, from P. tricornutum total RNA. In addition, we measured glutathione reductase activity in cellular extracts of P. tricornutum. Our results support the occurrence of TRX and GSH system in the diatom. Results afford valuable information to the incipient P. tricornutum genomic and proteomic, data that are of key relevance for the understanding of the alga biochemistry. Granted by UNL, CAI+D 2002; ANPCyT, PICT´03 01-14733, PAV´03 137