Characterization of the codY gene and its influence on biofilm formation in Bacillus cereus

Arch Microbiol. 2008 Jun;189(6):557-68. doi: 10.1007/s00203-008-0348-8. Epub 2008 Jan 24.


The foodborne pathogen Bacillus cereus can form biofilms on various food contact surfaces, leading to contamination of food products. To study the mechanisms of biofilm formation by B. cereus, a Tn5401 library was generated from strain UW101C. Eight thousand mutants were screened in EPS, a low nutrient medium. One mutant (M124), with a disruption in codY, developed fourfold less biofilm than the wild-type, and its defective biofilm phenotype was rescued by complementation. Addition of 0.1% casamino acids to EPS prolonged the duration of biofilms in the wild-type but not codY mutant. When decoyinine, a GTP synthesis inhibitor, was added to EPS, biofilm formation was decreased in the wild-type but not the mutant. The codY mutant produced three times higher protease activity than the wild-type. Zymogram and SDS-PAGE data showed that production of the protease ( approximately 130 kDa) was repressed by CodY. Addition of proteinase K to EPS decreased biofilm formation by the wild-type. Using a dpp-lacZ fusion reporter system, it was shown that that the B. cereus CodY can sense amino acids and GTP levels. These data suggest that by responding to amino acids and intracellular GTP levels CodY represses production of an unknown protease and is involved in biofilm formation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacillus cereus / chemistry
  • Bacillus cereus / enzymology
  • Bacillus cereus / genetics
  • Bacillus cereus / physiology*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Biofilms / drug effects
  • Biofilms / growth & development*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Endopeptidase K / pharmacology
  • Gene Expression Regulation, Bacterial*
  • Molecular Sequence Data
  • Molecular Weight
  • Mutagenesis, Insertional
  • Operon
  • Peptide Hydrolases / chemistry
  • Peptide Hydrolases / genetics
  • Peptide Hydrolases / metabolism
  • Repressor Proteins / chemistry
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Sequence Analysis, DNA


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Repressor Proteins
  • Peptide Hydrolases
  • Endopeptidase K

Associated data

  • GENBANK/EF467285