Bacterial–Bacterial Cell Interactions in Biofilms: Detection of Polysaccharide Intercellular Adhesins by Blotting and Confocal Microscopy

  • Kimberly K. Jefferson
  • Nuno Cerca
Part of the Methods in Molecular Biology™ book series (MIMB, volume 341)


Adhesive interactions between bacterial cells coupled with adherence to a solid surface can lead to the formation of a biofilm. The important role of biofilm formation in the pathogenesis of certain types of infection, especially those involving indwelling medical devices, is becoming increasingly apparent. Critical to the development of a biofilm is the elaboration of exopolysaccharide that contributes to substrate and intercellular adhesion. The synthesis and secretion of large exo-polysaccharides is a metabolically expensive process and is therefore often suppressed under conditions that favor the planktonic mode of growth. One way to identify the environmental cues that cause a given bacterial species to switch to the biofilm mode of growth is to monitor exo-polysaccharide elaboration in vitro. The exo-polysaccharide involved in biofilm formation in a number of bacterial species is a polymer of N-acetyl-glucosamine. In this chapter, we outline two methods that use wheat germ agglutinin, a lectin that binds to N-acetyl-glucosamine, to evaluate extracellular polysaccharide production by a variety of bacterial species.

Key Words

Biofilms exo-polysaccharide polysaccharide matrix bacteria lectins wheat germ agglutinin confocal microscopy 


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Copyright information

© Humana Press Inc. 2006

Authors and Affiliations

  • Kimberly K. Jefferson
    • 1
  • Nuno Cerca
    • 2
  1. 1.Department of Microbiology and ImmunologyVirginia Commonwealth UniversityRichmond
  2. 2.The Channing LaboratoryBrigham and Women’s Hospital, Harvard Medical SchoolBoston

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