FIG. 3.

Northern blot analysis of alr0760 and alr0761 (A) and alr0750 and hoxU (B) in Nostoc sp. strain PCC 7120 under aerobic (a) and dark, anaerobic (d/an) conditions. Probes for the Northern blot hybridization were obtained by PCR using Nostoc sp. strain PCC 7120 genomic DNA as the template and primer pairs Aalr0760F-Aalr0760R and Aalr0761F-Aalr0761R (A) and Aalr0750F-Aalr0750R and AhoxUF-AhoxUR (B) (see Table 1). Total RNA was isolated from Nostoc sp. strain PCC 7120 cultures grown in air or from cultures induced in dark, anaerobic conditions for 24 h, and a total amount of 10 μg RNA was used for each lane. The rnpB gene was used to standardize the loading and transfer of the RNA. Numbers on the left side of the panels indicate sizes in nucleotides (nt).