FIG. 2.

The developmental block of the citrate synthase mutant was accompanied by alterations in metabolism. MT1110 or BZ2 was grown on normal R2YE plates (25 mM TES buffer, pH 7.2) or the same medium supplemented with additional buffer (to 100 mM, R2YEB) for nine days (x axes) at 30°C. MT1110 produced aerial mycelium and pigmented antibiotics beginning at day 2 and spores beginning at day 4 on both types of plates. BZ2 produced neither aerial mycelium nor pigmented antibiotics on R2YE but was able to undergo a developmental program similar to that of MT1110 on R2YEB. Extracts of the agar medium were prepared as described in Materials and Methods in order to measure glucose concentration (millimolar) (A), pH (B), concentrations (millimolar) of organic acids (citrate, acetate, malate, pyruvate, succinate) (C to F), and concentrations (millimolar) of ammonium (C to F). (A and B) Squares, MT1110; triangles, BZ2; open symbols, R2YE; filled symbols, R2YEB. (C to F) Diamonds, acetate; squares, pyruvate; triangles, malate; exes, fumarate; circles, succinate; dotted line, NH₄.