Fig 7.

Cellular NAD(H) regulates secondary metabolite synthesis. Aspergillus nidulans wild type (WT), ΔNdxA (ΔndxA), ΔSirA (ΔsirA), and ΔSirA ΔNdxA (ΔsirA ΔndxA) were cultured for 72 h under normoxic and hypoxic (1% O₂) conditions. +NR, WT cultured with 0.3 mM nicotinamide riboside. (A) Intracellular NAD(H). (B) PCR-quantified ndxA transcripts. (C) Intracellular NAD(H) hydrolase activity. (D and E) Penicillin G production. (F) Penicillin G gene transcripts quantified by PCR. (G and H) Sterigmatocystin (ST) production. (I) Sterigmatocystin gene transcripts quantified by PCR. Data are means ± standard deviations (n = 3). *, P < 0.005; **, P < 0.03 (versus WT); †, P < 0.03 (versus WT with 1% O₂).