Antifungal Activity Assay Of Chinese Traditional Herbs And Screening For Yeast Gene Mutations In Utilization Of Non-fermentable Carbon Sources

PROJECT ONE: Object: To assess the reliability of both dry- and wet-disk diffusion methods in antifungal activity assay of extracts from Chinese traditional herbs. Methods: Candida albicans, the most important human fungal pathogen, was used as the test organism. The dry- and wet-disk diffusion methods were used to assay the anti-Candida albicans activity of extracts of Chinese traditional herbs and plants. Both methods have demonstrated good consistency with the formula Z2 = A log Q - M, which represents that the diagram square of inhibition zone is in direct ratio to the logarithm of drug content. There is no significant difference between the two methods. We examined the anti-Candida activities of ethanol extracts of 27 Chinese traditional herbs and oil extracts of 29 species of plants by both methods. The results show that Thamnolia vermicularis, Rhizorma Paridis and oil extracts of cinnamon contain inhibitory compounds against Candida albicans. Considering various solubility of herbs extracts, the wet disk diffusion method would be complementary to the dry method in assessing the antifungal activities.PROJECT TWO: Object: To screen gene mutations having defects in utilization of non-fermentable carbon sources in Saccharomyces cerevisiae. Methods: Replicating the gene deletion strain library of Saccharomyces cerevisiae onto YPD (2% glucose), YPE (2% ethanol) and YPG (2% glycerol) plates. Examining growth defects of strains on YPE and YPG in comparison to YPD. Confirmation of growth defects were assayed by serial dilutions. Results: 172 strains showing growth defects on both YPE and YPG, 16 strains only on YPG, and 35 strains only on YPE alone. Conclusion: identification of gene mutations in utilization of non-fermentable carbon sources would provide critical information for elucidation of carbon metabolisms in Saccharomyces cerevisiae.