Removal, accumulation and resistance to chromium in heterotrophic Euglena gracilis

摘要: The removal, uptake and toxicity of chromium in Euglena gracilis cultured absence presence malate with Cr(VI) or Cr(III) was evaluated. extrusion the extra- intracellular reduction capacity were determined contents molecules thiol group ascorbate also Absence medium decreased cell growth, increased toxicity, induced faster disappearance from medium, intramitochondrial accumulation. Both species soluble particulate ascorbate-dependent chromate reductase activities. Cells secreted large amounts thiol-molecules to bind extracellular Cr(III), respectively. former process supported by significant increase malate-producing enzyme activities assessment Cr-complexes indicated situ formation thiol-molecules. present results establish new paradigms regarding stress on algae-like microorganisms: (i) may be more toxic than Cr(VI), depending culture (or environmental) conditions; (ii) several simultaneous mechanisms are turned inactivate their effects. These mechanisms, now well understood further optimize, genetically modifying E. gracilis, facilitate development strategies for using this protist as potential bio-remediator chromium-polluted water systems.