FIG. 1.

Sulfate uptake by mycelium of P. chrysogenum strains Wisconsin 54-1255 (Low, low-penicillin-yielding strain), Panlabs P2 (Med, moderately yielding strain), and GB8 (High, relatively high yielding strain). Prior to the sulfate uptake experiments, the mycelia were grown under different growth conditions. Sulfate uptake was monitored after 40 h (▾), 64 h (○), and 88 h (●) of growth. The data shown are for a single experiment, but similar results were obtained in two other independent experiments. The detection limit of the assay is 2 pmol/mg (dry weight [dw]).