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Magnesium ions mitigate biofilm formation of Bacillus species via downregulation of matrix genes expression.

Oknin H, Steinberg D, Shemesh M - Front Microbiol (2015)

Bottom Line: Biofilm formation depends on the synthesis of extracellular matrix, whose production in Bacillus subtilis is specified by two major operons: the epsA-O and tapA operons.We analyzed the effect of Mg(2+) ions on matrix gene expression using transcriptional fusions of the promoters for eps and tapA to the gene encoding β galactosidase.The expression of the two matrix operons was reduced drastically in response to Mg(2+) ions suggesting about their inhibitory effect on expression of the matrix genes in B. subtilis.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Quality and Safety, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization, The Volcani Center Bet-Dagan, Israel ; Biofilm Research Laboratory, Faculty of Dental Medicine, Institute of Dental Sciences, Hebrew University-Hadassah Jerusalem, Israel.

ABSTRACT
The objective of this study was to investigate the effect of Mg(2+) ions on biofilm formation by Bacillus species, which are considered as problematic microorganisms in the food industry. We found that magnesium ions are capable to inhibit significantly biofilm formation of Bacillus species at 50 mM concentration and higher. We further report that Mg(2+) ions don't inhibit bacterial growth at elevated concentrations; hence, the mode of action of Mg(2+) ions is apparently specific to inhibition of biofilm formation. Biofilm formation depends on the synthesis of extracellular matrix, whose production in Bacillus subtilis is specified by two major operons: the epsA-O and tapA operons. We analyzed the effect of Mg(2+) ions on matrix gene expression using transcriptional fusions of the promoters for eps and tapA to the gene encoding β galactosidase. The expression of the two matrix operons was reduced drastically in response to Mg(2+) ions suggesting about their inhibitory effect on expression of the matrix genes in B. subtilis. Since the matrix gene expression is tightly controlled by Spo0A dependent pathway, we conclude that Mg(2+) ions could affect the signal transduction for biofilm formation through this pathway.

No MeSH data available.


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.
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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.


Magnesium ions mitigate biofilm formation of Bacillus species via downregulation of matrix genes expression.

Oknin H, Steinberg D, Shemesh M - Front Microbiol (2015)

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.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561805&req=5

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.

Bottom Line: Biofilm formation depends on the synthesis of extracellular matrix, whose production in Bacillus subtilis is specified by two major operons: the epsA-O and tapA operons.We analyzed the effect of Mg(2+) ions on matrix gene expression using transcriptional fusions of the promoters for eps and tapA to the gene encoding β galactosidase.The expression of the two matrix operons was reduced drastically in response to Mg(2+) ions suggesting about their inhibitory effect on expression of the matrix genes in B. subtilis.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Quality and Safety, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization, The Volcani Center Bet-Dagan, Israel ; Biofilm Research Laboratory, Faculty of Dental Medicine, Institute of Dental Sciences, Hebrew University-Hadassah Jerusalem, Israel.

ABSTRACT
The objective of this study was to investigate the effect of Mg(2+) ions on biofilm formation by Bacillus species, which are considered as problematic microorganisms in the food industry. We found that magnesium ions are capable to inhibit significantly biofilm formation of Bacillus species at 50 mM concentration and higher. We further report that Mg(2+) ions don't inhibit bacterial growth at elevated concentrations; hence, the mode of action of Mg(2+) ions is apparently specific to inhibition of biofilm formation. Biofilm formation depends on the synthesis of extracellular matrix, whose production in Bacillus subtilis is specified by two major operons: the epsA-O and tapA operons. We analyzed the effect of Mg(2+) ions on matrix gene expression using transcriptional fusions of the promoters for eps and tapA to the gene encoding β galactosidase. The expression of the two matrix operons was reduced drastically in response to Mg(2+) ions suggesting about their inhibitory effect on expression of the matrix genes in B. subtilis. Since the matrix gene expression is tightly controlled by Spo0A dependent pathway, we conclude that Mg(2+) ions could affect the signal transduction for biofilm formation through this pathway.

No MeSH data available.