Figure 3.

Intracellular cAMP level as a function of time after addition of 100 mM glucose (A) or 2 mM 2,4-dinitrophenol (B) in strains in which PDE1 has been replaced by pde1^ala252: wild-type strain (W303–1A) (•); pde1Δ strain (PM941) (○); pde1^ala252 strain (PM581) (▴); and pde1^ala252 pde2Δ strain (PM582) (▵). (C) Heat shock resistance of strains carrying different alleles of the PDE genes. Cells were grown in YPD medium until OD₆₀₀ = 2.0–2.5, after which the OD was adjusted to 2 with the same medium. The cell suspension was heat shocked for 20 min at 50°C in a water bath. Treated and untreated cell suspensions were spotted on YPD plates and incubated at 30°C for 2 d. Serial dilutions were made with a factor of 10. (D) Basal cAMP level during exponential growth on YPD medium in RAS2^val19 strains with deletion and/or modification of the phosphodiesterase genes.