Proteomic analysis of an environmental isolate of Rhodotorula mucilaginosa after arsenic and cadmium challenge: Identification of a protein expression signature for heavy metal exposure

摘要

A metal-resistant Rhodotorula mucilaginosa strain was isolated from an industrial wastewater. Effects on reduced/oxidized glutathione (GSSG/GSH), antioxidant enzymes and proteome were assessed on metal challenge (100 mg/L). Increased GSH (mM/g) was found with CdCl2 (18.43 +/- 3.34), NaAsO2 (14.76 +/- 2.14), CuSO4 (14.73 +/- 2.49), and Pb(NO3)(2) (15.74 +/- 5.3) versus control (7.67 +/- 0.95). GSH:GSSG ratio decreased with CdCl2, NaAsO2, and Pb(NO3)(2) but not with CuSO4 and cysteine-containing protein levels increased with CdCl2 and NaAsO2. NaAsO2 exposure enhanced glutathione transferase activity but this decreased with CdCl2. Both metals significantly increased glutathione reductase and catalase activities. Metabolism-dependent uptake of Cd and As (12-day exposure) of approximately 65 mg/g was observed in live cells with greater cell surface interaction for As compared to Cd. A particular role for arsenic oxidase in As resistance was identified.