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Plasmid-mediated formaldehyde resistance in Serratia marcescens and Escherichia coli: alterations in the cell surface
P M Kaulfers1, H Karch, R Laufs
1Institut für Medizinische Mikrobiologie und Immunologie, Universitäts-Krankenhaus Eppendorf, Hamburg, Federal Republic of Germany.
Abstract:
The plasmid-mediated formaldehyde resistance of Serratia marcescens and Escherichia coli was examined. For that purpose the outer membranes of isogenic strains (with and without resistance plasmid) were compared. No quantitative or immunological differences in lipopolysaccharide of resistant and sensitive strains were noted. By contrast analysis of outer membrane proteins revealed that the sensitive variants had a higher protein content than the resistant strains. When outer membrane proteins were separated by SDS-PAGE the number of bands seemed identical for sensitive and resistant strains but the intensity of some of the bands was greater for the sensitive isolates. In addition, the surface hydrophobicity was greater for the resistance than for the sensitive strains. These findings suggest that the formaldehyde resistance plasmid of Serratia marcescens confer changes in cell surface proteins and surface hydrophobicity.
Insights
Plasmid-mediated formaldehyde resistance in bacteria alters cell surface proteins and hydrophobicity. Resistant strains showed reduced outer membrane protein content and increased surface hydrophobicity compared to sensitive strains.
Area of Science:
- Microbiology
- Bacterial genetics
- Molecular biology
Background:
- Formaldehyde is a common biocide and disinfectant.
- Bacterial resistance to formaldehyde can be mediated by plasmids.
- Understanding the mechanisms of formaldehyde resistance is crucial for controlling microbial contamination.
Purpose of the Study:
- To investigate the role of outer membrane components in plasmid-mediated formaldehyde resistance in Serratia marcescens and Escherichia coli.
- To compare the outer membrane protein and lipopolysaccharide profiles of formaldehyde-resistant and sensitive bacterial strains.
Main Methods:
- Comparative analysis of outer membranes from isogenic resistant and sensitive strains.
- Lipopolysaccharide (LPS) quantification and immunological comparison.
- Outer membrane protein separation and analysis using SDS-PAGE.
- Assessment of surface hydrophobicity.
Main Results:
- No significant quantitative or immunological differences in lipopolysaccharide were observed between resistant and sensitive strains.
- Outer membrane protein analysis revealed lower protein content in resistant strains compared to sensitive strains.
- SDS-PAGE indicated altered band intensities in outer membrane proteins of resistant strains, suggesting changes in protein expression.
- Formaldehyde-resistant strains exhibited increased surface hydrophobicity.
Conclusions:
- Plasmid-mediated formaldehyde resistance in Serratia marcescens and Escherichia coli is associated with alterations in outer membrane protein composition and surface hydrophobicity.
- These changes in cell surface characteristics may contribute to the resistance phenotype.
- Further research is needed to elucidate the specific proteins and pathways involved.