Biotechnology World Convention

Biography

Biography: Wai Kit Chan

Abstract

An arsenic-resistant fungal strain, Acidomyces acidophilus WKC1 was isolated from waste roaster pile of a disused tin mine in Cornwall (UK) that was found to contain 18970 mg kg^-1 arsenic (As). These tin mining areas are inhospitable due their extreme environmental conditions such as acutely acidity and high concentrations of heavy metals/metalloids, particularly arsenic. The A. acidophilus WKC1 strain exhibited remarkable tolerance to high arsenic concentration for instance, it can tolerate As(V) up to 22500 mg L^-1. A comparative protein responses analysis of A. acidophilus WKC1 exposed to arsenic and its control was performed using hybrid quadrupole-Orbitrap mass spectrometer. This proteomics approach revealed the mechanism behind the outstanding resistance and tolerance of A. acidophilus WKC1 against arsenic toxicity. When A. acidophilus WKC1 strain was exposed for 24 hours to 500 mg L^-1 of sodium arsenate (Na₂HAsO₄), the enzymatic activities showed increased glutathione reductase, catalase and superoxide dismutase activities but reduced glutathione transferase activity. A total of 262 differentially expressed proteins were detected, of these 175 were up-regulated and 63 were down regulated following exposure to arsenic. These proteins included ones know to be involved in cellular stress responses, energy production, transport and proteins/enzymes synthesis when exposed to arsenic. In addition, 14 proteins were switched off and 10 proteins were switched on in the presence of arsenic. As far as we are aware this is the first report on proteomic study using A. acidophilus strain and next generation semi-quantitative mass spectrometry in arsenic resistance.