title: Norspermidine is not a self-produced trigger for biofilm disassembly.
abstract: Formation of Bacillus subtilis biofilms, consisting of cells encapsulated within an extracellular matrix of exopolysaccharide and protein, requires the polyamine spermidine. A recent study reported that (1) related polyamine norspermidine is synthesized by B. subtilis using the equivalent of the Vibrio cholerae biosynthetic pathway, (2) exogenous norspermidine at 25 μM prevents B. subtilis biofilm formation, (3) endogenous norspermidine is present in biofilms at 50-80 μM, and (4) norspermidine prevents biofilm formation by condensing biofilm exopolysaccharide. In contrast, we find that, at concentrations up to 200 μM, exogenous norspermidine promotes biofilm formation. We find that norspermidine is absent in wild-type B. subtilis biofilms at all stages, and higher concentrations of exogenous norspermidine eventually inhibit planktonic growth and biofilm formation in an exopolysaccharide-independent manner. Moreover, orthologs of the V. cholerae norspermidine biosynthetic pathway are absent from B. subtilis, confirming that norspermidine is not physiologically relevant to biofilm function in this species.
authors: Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD15EH, UK.
authors: Laura
authors: L
authors: Hobley
authors: Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors: Sok Ho
authors: SH
authors: Kim
authors: Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors: Yukari
authors: Y
authors: Maezato
authors: Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD15EH, UK.
authors: Susan
authors: S
authors: Wyllie
authors: Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD15EH, UK.
authors: Alan H
authors: AH
authors: Fairlamb
authors: Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD15EH, UK. Electronic address: n.r.stanleywall@dundee.ac.uk.
authors: Nicola R
authors: NR
authors: Stanley-Wall
authors: Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address: anthony.michael@utsouthwestern.edu.
authors: Anthony J
authors: AJ
authors: Michael
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000254:growth & development / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D008969:Molecular Sequence Data; D010933:Plankton / Q000254:growth & development; D016415:Sequence Alignment; D013095:Spermidine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D014734:Vibrio cholerae / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D005680:gamma-Aminobutyric Acid; C006760:norspermidine; D013095:Spermidine