Norspermidine – A self-produced trigger for biofilm disassembly that targets exopolysaccharide

S Cao; I Kolodkin-Gal; T Boettcher; L Chai; R Kolter; R Losick; J Clardy

doi:10.1055/s-0032-1320735

Planta Medica, Table of Contents

Norspermidine – A self-produced trigger for biofilm disassembly that targets exopolysaccharide

S Cao ¹, I Kolodkin-Gal ², T Boettcher ¹, L Chai ³, R Kolter ³, R Losick ², J Clardy ¹

¹Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
²Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
³Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA

Abstract

Biofilms are structured communities of bacteria that are held together by an extracellular matrix consisting of protein, exopolysaccharide and DNA etc. Biofilms often have a limited lifespan, disassembling as nutrients become exhausted and waste products accumulate. D-amino acids were previously identified as a self-produced factor that mediates biofilm disassembly by causing the release of the protein component of the matrix in Bacillus subtilis. Here we report that B. subtilis produces an additional biofilm disassembly factor, norspermidine (H₂N-CH₂-CH₂-CH₂-NH- CH₂-CH₂-CH₂-NH₂). Dynamic light scattering and scanning electron microscopy experiments indicated that norspermidine interacts directly and specifically with exopolysaccharide. D-amino acids and norspermidine acted together to break down existing biofilms and mutants blocked in the production of both factors formed long-lived biofilms. Norspermidine, but not closely related polyamines, prevented biofilm formation by B. subtilis, Escherichia coli, and Staphylococcus aureus.