Differential proteomics of Penicillium marneffei : a dimorphic fungal pathogen

Abstract

Penicillium marneffei can be characterized as an opportunistic pathogen. It is usually only pathogenic to individuals who are immunodeficient. The dimorphism of P. marneffei is what makes it an interesting organism to study because of its relationship to disease. In the lab, it grows as a mold at 25°C, but when isolated from an infected person or rat, only the single-celled yeast form is seen. This phenomenon can be simulated in the lab by growing cultures at room temperature (25°C) and body temperature (37°). The explanation for this dimorphic switch can be arrived at by the study of changes in the protein makeup of the fungal cells. This proteomics approach to analyzing P. marneffei could illuminate the specific change necessary for dimorphism. Growing the cultures at these two different temperatures and respectively isolating the protein is the starting point for this proteomics approach to studying the dimorphic growth of P. marneffei. Two dimensional gel electrophoretic analysis of the protein yields protein profiles of the cultures. Comparative analysis of the profiles identify proteins that are distinctly different between the two morphologies. These spots can be excised and the proteins can be sequenced using mass spectrometry. Th differential protein expression and subsequent identification provides a way in which to study the molecular mechanism of P. marneffei. Using P. marneffei as a model for other infectious organisms that may share similar molecular mechanisms will aid in the understanding of dimorphism and its possible link to pathogenicity.