FIG. 4.

Effects of veA deletion on transcription of genes implicated in production of secondary metabolites during morphological development in A. nidulans. (A) Transcriptional patterns of genes involved in secondary metabolism, aflR and ipnA, were evaluated by Northern analysis in the veA⁺ and ΔveA strains. Total RNAs of the veA⁺ and ΔveA strains were isolated 30, 45, and 60 h after inoculation on solid YGT medium (left). rRNA stained with ethidium bromide is shown to indicate RNA loading. mRNA was quantitated by densitometry and plotted as relative band intensity normalized to rRNA and to the highest band intensity in each graph (considered as 1 U) (right). Two separate repetitions of these experiments yielded similar results. (B) ST analysis by TLC. The uncharacterized compound observed in ΔveA near the ST R_f is not ST (in this assay, ST fluoresces bright yellow while the unknown compound fluoresced blue). Std, standard; *, other uncharacterized metabolites absent or present in different amounts in ΔveA with respect to veA⁺.