Cytological Characterization of Saccharomyces Cerevisiae via Fluorescent Proteins Before and After Desiccation

Italia Weaver, Corrine Capitonoff-Sullivan, and Dr. Hugo Tapia


Most of our understanding of biology occurs within a narrow moisture window. Macromolecules, cells, and organisms typically require above 98% relative humidity to function. Yet, survival at an extremely low water level (termed anhydrobiosis), is essential for most seeds, spores, and microscopic animals. How macromolecules, cells, and organisms can establish and maintain reversible suspension of biological activity at
low water content is not well understood. To elucidate how life can persist without water, we must understand how molecules, cells, and organisms protect themselves during
desiccation and rehydration. Research in the Tapia lab is centered on understanding how the yeast Saccharomyces cerevisiae becomes tolerant to desiccation. Previous
findings from our lab have demonstrated that yeast can become desiccation tolerant upon nutrient depletion or through the introduction of specific protectants. Here we will
focus on elucidating cytological changes that occur to a yeast cell upon cycles of repeated desiccation and rehydration. We will attempt to characterize any major observable changes to the cell upon drying and rehydrating a cell. Using a series of
transgenic yeast strains that express a fluorescent protein fused to our protein of interest (e.g. gene Actin Binding Protein Abp1 is fused with Green Fluorescent Protein GFP, creating Abp1-GFP), we will characterize the localization of various cellular organelles via fluorescent microscopy before and after desiccation. We have preliminary
data observing different fluorescent proteins disperse from their original localization to different parts of the cell upon desiccation and rehydration. A nucleolus localized protein (Nop1-GFP) before drying is no longer associated with the nucleolus upon drying and rehydrating. Similar results have been observed with other nuclear localized proteins. Further experiments using vital dyes as well as different drying parameters will be used.

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