Northern analysis of light- and env1 -responsive genes. Strains were grown on Mandels Andreotti minimal medium with 1% (w/v) glycerol as carbon source for 24 h in darkness (DD) and harvested after the indicated time (DL) of illumination (1800 lux, 25 μmol photons m-2s-1). A representative hybridization with 18S rRNA for every set of Northerns is given below the respective series. Transcript abundance is given below the blots and was measured for wild-type QM9414 (Q) and env1PAS- by densitometry to verify up-regulation until 60 min of illumination, related to 18S rRNA and normalized to the dark control of the wild-type strain (QM9414, 24 h, DD). If no transcript was detected in QM9414 in darkness, the values represent signal strength above background. (A) Transcription of genes upregulated by light but not in the env1PAS- strain. (B) Transcription of genes upregulated both by light and in the env1PAS- strain. (C) Transcription of genes upregulated by light, which show increased upregulation in the env1PAS- strain.