Site Selection for Bud and Germ Tube Emergence in Candida albicans

Abstract

SUMMARY: The site selection for bud and germ tube emergence has been studied in the dimorphic yeast Candida albicans. The fluorescent dye Calcofluor was used to stain bud scars. Two different modes of site selection were observed in yeasts. On cells cultivated at 23-28 °C, buds emerged primarily at one end of the cell at adjacent sites suggesting a type of persistent memory. Sites selected on yeasts growing at 37 °C were non-adjacent and scattered over the cell. The pattern of bud emergence during resumption of budding from stationary phase, or after temperature shift between conditions, was not a simple transition between modes. During these transitions the budding pattern sequentially passed through non-adjacent and adjacent budding modes before establishing the pattern characteristic of the growth temperature. Germ tubes emerged in a non-adjacent pattern from cells grown to stationary phase at 28 °C. The higher frequency of non-adjacent emergence and the absence of sequential pattern changing in site selection for germ tubes suggested that non-adjacent site selection for germ tubes and buds might not be the same.