Table 3.

Effect of 5-fluorodihydrouracil on viability and plasmid loss of S. cerevisiae strains expressing the fungal dihydrouracil oxidase genes Aadho and Scdho

Strain	Relevant genotype	CFU (%)		Plasmid loss (%)
		SMD + ura	SMD + ura0.1 + 5F-dhu	SMD + ura	SMD + ura0.1 + 5F-dhu
IME426	ura3-52 pUD63 (URA3)	84 ± 2	87 ± 1	67 ± 2	50 ± 1
IME410	ura3-52 pUDE736 (URA3 Aadho)	92 ± 2	44 ± 6	61 ± 3	99 ± 0
IME414	ura3-52 pUDE737 (URA3 Scdho)	91 ± 0	57 ± 5	60 ± 2	94 ± 1

Yeast strains were grown until late-exponential phase on either SMD with 1.5 g L⁻¹ uracil (SMD + ura) or on SMD supplemented with both 0.15 g L⁻¹ uracil (SMD + ura0.1) and 2.5 g L⁻¹ 5F-dhu. Viability was calculated as the percentage of 768 cells plated on SMD + ura that formed colonies. Plasmid loss was calculated from the ratio of cell counts after plating on SMD and SMD + ura. Results are presented as the average ± mean deviation of data obtained with duplicate cultures for each strain