Fig. 5.

Effects of loss of de novo or salvage pathway on growth and NAD(H) levels in an idhΔ yeast strain. The idhΔ (○), idhΔ bna6Δ (▽), and idhΔ pnc1Δ (□) yeast strains growing logarithmically in YP glucose medium were harvested and resuspended in YP acetate medium. Samples of the cultures taken before (time 0) or at times shown after the transfer were diluted and plated to determine viable cell numbers (A); these are expressed relative to initial values set at 1.0. Culture samples were also harvested to prepare extracts for measurements of NAD⁺ and NADH as described under Materials and methods. Concentrations are expressed as total cofactor concentrations ([NAD⁺ + NADH]/viable cell/cell volume) (B) and as the ratio of oxidized to reduced cofactor (C).