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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 Na+ ions on biofilm formation by B. subtilis. The effect of addition of different concentrations of NaCl to LBGM medium on pellicle formation by B. subtilis NCIB3610.
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Figure 4: The effect of Na+ ions on biofilm formation by B. subtilis. The effect of addition of different concentrations of NaCl to LBGM medium on pellicle formation by B. subtilis NCIB3610.

Mentions: Subsequently, we wondered whether other common salts may also affect the biofilm formation at the same concentration as it does MgCl2. Therefore, we tested the effect of NaCl and CaCl2 on biofilm formation by B. subtilis. Notably, none of those compounds could inhibit the biofilm formation in the same manner as MgCl2. Although, there was not a significant difference in pellicle formation or bundling ability of B. subtilis cells in the presence of NaCl at tested concentrations (Figure 4), nonetheless, NaCl could slightly affect the expression of eps operon at 100 mM concentration (Figure 2B). Interestingly, we detected a very slight inhibition in the pellicle formation in the presence of 50 mM or higher concentrations of CaCl2 (Figure 5), while expression of the eps and tapA operons was found to be somewhat downregulated (Figure 2C). It should be noted that neither NaCl nor CaCl2 affected notably bacterial growth (Supplementary Figures 2 and 3).


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 Na+ ions on biofilm formation by B. subtilis. The effect of addition of different concentrations of NaCl to LBGM medium on pellicle formation by B. subtilis NCIB3610.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 4: The effect of Na+ ions on biofilm formation by B. subtilis. The effect of addition of different concentrations of NaCl to LBGM medium on pellicle formation by B. subtilis NCIB3610.
Mentions: Subsequently, we wondered whether other common salts may also affect the biofilm formation at the same concentration as it does MgCl2. Therefore, we tested the effect of NaCl and CaCl2 on biofilm formation by B. subtilis. Notably, none of those compounds could inhibit the biofilm formation in the same manner as MgCl2. Although, there was not a significant difference in pellicle formation or bundling ability of B. subtilis cells in the presence of NaCl at tested concentrations (Figure 4), nonetheless, NaCl could slightly affect the expression of eps operon at 100 mM concentration (Figure 2B). Interestingly, we detected a very slight inhibition in the pellicle formation in the presence of 50 mM or higher concentrations of CaCl2 (Figure 5), while expression of the eps and tapA operons was found to be somewhat downregulated (Figure 2C). It should be noted that neither NaCl nor CaCl2 affected notably bacterial growth (Supplementary Figures 2 and 3).

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.