Proteomic Analysis of Neurospora crassa Using the Non-Preferred Carbon Source Acetic Acid

Abstract

The Ascomycete fungus, Neurospora crassa, has been used for over 90 years as an ideal model organism in a variety of fields ranging from genetics to molecular biology. N. crassa is able to use multiple different carbon sources under varying conditions. It metabolizes preferred carbon sources such as dextrose, but has the ability to metabolize non-preferred carbon sources such as acetic acid also. Little research has been done concerning protein expression using non-preferred carbon sources, but there has been growing interest in non-preferred or otherwise thought toxic nutrient sources, since NASA's discovery of bacteria able to use arsenic as a sole source of nutrition, which was thought to be toxic to all forms of life. In this study, we analyze the protein profiles of wild-type N. crassa grown on two different carbon sources: 2% dextrose (preferred carbon source), and 10% sodium acetate (non-preferred carbon source). Wild-type N. crassa was grown on Vogel's minimal media and shifted to one of two carbon sources utilized in our study. Afterwards, protein was extracted from N. crassa tissue and two-dimensional gel electrophoresis (2-DGE) was performed. Following 2-DGE the gel images were examined using PDQuest[TM] 2-D analysis software. From the 2-DGE analysis using PDQuest[TM], it was shown that acetic acid, a non-preferred carbon source, had a much higher number of protein spots expressed, in comparison to the preferred carbon source, dextrose. The total number of protein spots visualized for acetic acid was found to be 257 and the total number for dextrose was found to be 138. The two carbon sources were found to share only 121 proteins. This goes against current research that was previously performed, in which preferred carbon sources display greater numbers of proteins in relation to non-preferred carbon sources.