Požadovaný rozpočet: 211.218 EUR

Blastocystis is a unicellular human intestinal parasite, of controversial pathogenicity, that belongs to a diverse eukaryotic phylum called the Stramenopiles. Since Blastocystis is a strict anaerobe, it was thought that it might possess hydrogenosomes, anaerobic ATPgenerating organelles related to mitochondria. In contrast to typical hydrogenosomes, Blastocystis has mitochondrion-like organelles (MLOs) with cristae, a transmembrane potential and DNA. Recent work has demonstrated a mitochondrial genome and bioinformatics analyses of expressed sequence tags (ESTs) have identified 115 putative mitochondrial and hydrogenosomal proteins. Amongst these was [FeFe'>-hydrogenase, a hydrogenosomal marker protein that was shown to be localized to the MLOs. The organelles are also predicted to have canonical mitochondrial pathways for amino acid metabolism, ironsulphur (Fe-S) cluster biogenesis and an incomplete tricarboxylic acid cycle. These data suggest that Blastocystis MLOs may be some kind of metabolic intermediate between mitochondria and hydrogenosomes. To test the predicted functions of these MLOs, I will immunolocalize and functionally characterize components of several of its predicted pathways including Fe/S cluster biosynthesis, amino acid metabolism and mitochondrial import. Furthermore, I will purify the Blastocystis MLOs for in vivo assays and proteomic analyses. With these methods I aim to identify the biochemical raison d’être of the mitochondria-like organelle for the parasite. By comparing its pathways with those in other eukaryote lineages, I will determine: (1) the unique biochemical properties of Blastocystis MLO, (2) how Blastocystis MLOs have adapted to an anaerobic and parasitic lifestyle, and (3) how environmental stimuli affect the metabolism of these MLOs. This project will provide basic information on the essential functions mitochondria across eukaryotic diversity as well as illuminate the metabolic plasticity of these fundamental organelles.

Žadatel: Univerzita Karlova