Fig 1.
Activity of the AlgU sigma factor in A. vinelandii.
A transcriptional PalgC-gusA fusion was used to estimate the activity of AlgU in the background of the wild-type strain AEIV (solid line) or in the algU mutant (dotted line). Cells were cultured in minimum Burk’s medium supplemented with sucrose (vegetative growth) or n-butanol (encystment-inducing conditions) as the sole carbon source for the indicated time. The bars of standard deviation from three independent experiments are shown.
Fig 2.
KEGG pathway enrichment of proteins of the AlgU regulon in A. vinelandii.
The analysis was conducted for the differentially expressed proteins in the absence of the sigma factor AlgU under vegetative (A) or encystment-induced (B) conditions. Positive and negative axes represent the numbers of up- or downregulated proteins, respectively.
Table 1.
Relative mRNA levels of some genes encoding proteins under the positive control of AlgU.
Table 2.
Selected proteins under the positive control of AlgU under vegetative growing conditions.
Table 3.
Selected proteins positively control by AlgU during encysting conditions.
Fig 3.
The production of ARs is impaired in the absence of AlgU.
A. Staining with Fast Blue B of ARs produced by strain AEIV (WT) and by its derivative algU mutant under encysting conditions. Cells were grown on Burk’s-butanol for 48 h before staining. B. ARs quantification under vegetative growth. The wild-type strains AEIV, ATCC 9046 and ATCC 12518, and the AEIV derivative mutant algU were cultivated in Burk’s-sucrose medium for 24 h prior to ARs extraction. The bars of standard deviation from three independent experiments are shown. The asterisks denote statistical significance (unpaired Student’s t-test, *P<0.05; **P<0.01) when compared to the wild-type strain AEIV.
Fig 4.
Sequence logo for AlgU DNA binding motifs.
A PSSM was used to identify AlgU binding motifs in the genome of P. aeruginosa (A) or A. vinelandii (B) (see Materials and Methods section for details). The predicted AlgU binding motifs are shown with 16 (upper panels) or 17 (lower panels) bp spacers, between the -10 and -35 boxes. The relative sizes of the letters represent their frequency in the sequences.