Project description:Although copper is an essential nutrient crucial for many biological processes, an excessive concentration can be toxic and lead to cell death. The metabolism of this two-faced metal must be strictly regulated at the cell level. In this study, we investigated copper homeostasis in two related unicellular organisms: nonpathogenic Naegleria gruberi and the “brain-eating amoeba” Naegleria fowleri. We identified and confirmed the function of their specific copper transporters securing the main pathway of copper acquisition. Adjusting to different environments with varying copper levels during the life cycle of these organisms requires various metabolic adaptations. Using comparative proteomic analyses, measuring oxygen consumption, and enzymatic determination of NADH dehydrogenase, we showed that both amoebas respond to copper deprivation by upregulating the components of the branched electron transport chain: the alternative oxidase and alternative NADH dehydrogenase. Interestingly, analysis of iron acquisition indicated that this system is copper-dependent in N. gruberi but not in its pathogenic relative. Importantly, we identified a potential key protein of copper metabolism of N. gruberi, the homolog of human DJ-1 protein, which is known to be linked to Parkinson’s disease. Altogether, our study reveals the mechanisms underlying copper metabolism in the model amoeba N. gruberi and the fatal pathogen N. fowleri and highlights the differences between the two amoebas.
Project description:A pediatric case of primary amoebic meningoencephalitis due to Naegleria fowleri diagnosed by next-generation sequencing of cerebrospinal fluid and blood samples
Project description:Naegleria gruberi is a single-celled eukaryote best known for its remarkable ability to form an entire microtubule cytoskeleton de novo during its metamorphosis from an amoeba into a flagellate, including two basal bodies (equivalent to centrioles), two flagella (equivalent to cilia), and a cytoplasmic microtubule array. This full-genome transcriptional analysis, performed at 20-minute intervals throughout Naegleria differentiation, reveals vast transcriptional changes, including the differential expression of cytoskeletal, metabolism, signaling and stress response genes. Naegleria gruberi (strain NEG) was grown in association with Kleibsiella pneumoniae on solid media. Cells were prepared and differentiated using standard protocols, and harvested at 0, 20, 40, 60 and 80 minutes after initiation of differentiation.
