The effect of Mg2+, Ca2+, and Na+ ions on transcription | Open-i
Figure 2: The effect of Mg2+, Ca2+, and Na+ ions on transcription of the operons responsible for the matrix production. Transcription of the operons responsible for the matrix production is differentially regulated in response to (A) Mg2+, (B) Na+, and (C) Ca2+ ions. The left panel shows results from RL4548 cells that bear the Peps-lacZ transcriptional fusion and the right panel demonstrates results from RL4582 cells that bear the PtapA-lacZ transcriptional fusion;. *P-value < 0.05 compared to control.
Mentions: Biofilm formation depends on the synthesis of extracellular matrix, whose production in B. subtilis is specified by two major operons: the epsA-O and tapA operons (Kearns et al., 2005; Branda et al., 2006; Chu et al., 2006). The epsA-O operon is responsible for the production of the exopolysaccharides whereas the tapA operon is responsible for the production of amyloid-like fibers (Chai et al., 2008; Romero et al., 2010). We hypothesized that the inhibitory effect of Mg2+ ions on biofilm formation could be due to down-regulation of the genes involved in matrix synthesis. To test this hypothesis, we analyzed the effect of Mg2+ ions on matrix gene expression using transcriptional fusions of the promoters for epsA-O and tapA to the gene encoding β galactosidase. The expression of the matrix operons was notably reduced in response to the addition of Mg2+ ions (Figure 2A). The reduction in eps expression was relatively small (around four-fold) but significant, while tapA expression was decreased almost 14.5-fold at elevated concentrations of Mg2+ ions (Figure 2A). This result suggests that addition of Mg2+ ions down regulates expression of the extracellular matrix genes in B. subtilis.
The effect of Mg2+, Ca2+, and Na+ ions on transcription | Open-i
Figure 2: The effect of Mg2+, Ca2+, and Na+ ions on transcription of the operons responsible for the matrix production. Transcription of the operons responsible for the matrix production is differentially regulated in response to (A) Mg2+, (B) Na+, and (C) Ca2+ ions. The left panel shows results from RL4548 cells that bear the Peps-lacZ transcriptional fusion and the right panel demonstrates results from RL4582 cells that bear the PtapA-lacZ transcriptional fusion;. *P-value < 0.05 compared to control.
Mentions: Biofilm formation depends on the synthesis of extracellular matrix, whose production in B. subtilis is specified by two major operons: the epsA-O and tapA operons (Kearns et al., 2005; Branda et al., 2006; Chu et al., 2006). The epsA-O operon is responsible for the production of the exopolysaccharides where
as the tapA operon is responsible for the production of amyloid-like fibers (Chai et al., 2008; Romero et al., 2010). We hypothesized that the inhibitory effect of Mg2+ ions on biofilm formation could be due to down-regulation of the genes involved in matrix synthesis. To test this hypothesis, we analyzed the effect of Mg2+ ions on matrix gene expression using transcriptional fusions of the promoters for epsA-O and tapA to the gene encoding β galactosidase. The expression of the matrix operons was notably reduced in response to the addition of Mg2+ ions (Figure 2A). The reduction in eps expression was relatively small (around four-fold) but significant, while tapA expression was decreased almost 14.5-fold at elevated concentrations of Mg2+ ions (Figure 2A). This result suggests that addition of Mg2+ ions down regulates expression of the extracellular matrix genes in B. subtilis.