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Influence of magnesium ions on biofilm formation by Pseudomonas fluorescens
1Department of Biological Sciences, Kent State University, Kent, OH 44242, USA.
Abstract:
Mg(2+) can potentially influence bacterial adhesion directly through effects on electrostatic interactions and indirectly by affecting physiology-dependent attachment processes. However, the effects of Mg(2+) on biofilm structure are largely unknown. In this study, Pseudomonas fluorescens was used to investigate the influence of Mg(2+) concentration (0, 0.1 and 1.0mM MgCl(2)) on biofilm growth. Planktonic and attached cells were enumerated (based on DAPI staining) while biofilm structures were examined via confocal laser scanning microscopy and three-dimensional structures were reconstructed. Mg(2+) concentration had no influence on growth of planktonic cells but, during biofilm formation, Mg(2+) increased the abundance of attached cells. For attached cells, the influence of Mg(2+) concentration changed over time, suggesting that the role of Mg(2+) in bacterial attachment is complex and dynamic. Biofilm structures were heterogeneous and surface colonization and depth increased with increasing Mg(2+) concentrations. Overall, for P. fluorescens, Mg(2+) increased initial attachment and altered subsequent biofilm formation and structure.
Insights
Magnesium ions (Mg2+) enhance Pseudomonas fluorescens attachment to surfaces, increasing biofilm formation and structural complexity. This study reveals Mg2+ significantly impacts bacterial biofilm development and architecture.
Area of Science:
- Microbiology
- Biophysics
Background:
- Magnesium ions (Mg2+) are known to influence bacterial adhesion via electrostatic interactions and physiological processes.
- The specific impact of Mg2+ on the structural development of bacterial biofilms remains largely uncharacterized.
Purpose of the Study:
- To investigate the effect of varying magnesium chloride (MgCl2) concentrations on the biofilm formation and structure of Pseudomonas fluorescens.
- To elucidate the role of Mg2+ in bacterial attachment and biofilm architecture.
Main Methods:
- Enumeration of planktonic and attached Pseudomonas fluorescens cells using DAPI staining.
- Examination of biofilm structures using confocal laser scanning microscopy (CLSM).
- Reconstruction of three-dimensional biofilm architectures.
Main Results:
- Mg2+ concentration did not affect planktonic cell growth but significantly increased attached cell abundance during biofilm formation.
- The influence of Mg2+ on attached cells varied dynamically over time.
- Increasing Mg2+ concentrations led to increased surface colonization and biofilm depth, resulting in heterogeneous biofilm structures.
Conclusions:
- Mg2+ plays a crucial role in enhancing initial bacterial attachment for Pseudomonas fluorescens.
- Magnesium ions dynamically alter biofilm formation processes and influence the final biofilm structure and architecture.
- The findings highlight the complex and time-dependent role of Mg2+ in bacterial biofilm development.
