Analysis of a 30 kbp plasmid encoding histidine decarboxylase gene in Tetragenococcus halophilus isolated from fish sauce

Int J Food Microbiol. 2008 Aug 15;126(1-2):202-9. doi: 10.1016/j.ijfoodmicro.2008.05.025. Epub 2008 May 25.


In order to analyze the genes related to the histamine production, a strain of histamine producing halophilic bacteria, referred to as strain H, was isolated using enrichment culture and dilution-to-extinction methods with histidine broth inoculated from the fish sauce mashes. The two Japanese fish sauce mashes used, accumulate over 1000 mg/l of histamine. Phenotypic and 16 S rRNA gene sequence analyses identified strain H as Tetragenococcus halophilus, the predominant histamine producing bacteria present during fish sauce fermentation. Genetic analyses (PCR and Southern blot) of the histamine producing strain confirmed that the strain harbored a 30 kbp plasmid (pHDC) encoding a single copy of the pyruvoyl dependent histidine decarboxylase gene (hdc). A comparison of hdcA that is a structural gene of histidine decarboxylase among strain H, Lactobacillus hilgardii 0006, L. sakei LTH2076, Oenococcus oeni 9204, T. halophilus and T. muriaticus JCM10006 (T) indicated >99% sequence similarity. The hdc gene cluster consisted of 4 ORFs, hdcP, hdcA, hdcB, and hdcRS, and were almost identical to that of L. hilgardii 0006 with 99% sequence similarity including the structural hdc spacer region. However, the approximately 500 bp regions upstream and downstream of the hdc gene were different between that of strain H and L. hilgardii 0006. The complete sequence of pHDC revealed 29,924 nucleotides including 28 ORFs, two pairs of IR (inverted repeat), similar sequence of plasmid conjugative elements, and a theta-type replicon. These results suggested that hdc could be encoded on transformable elements among lactic acid bacteria.

MeSH terms

  • Base Sequence
  • Cloning, Molecular
  • Cluster Analysis
  • Fermentation
  • Fish Products / microbiology*
  • Food Microbiology
  • Foodborne Diseases / microbiology*
  • Histamine / biosynthesis*
  • Histidine Decarboxylase / genetics*
  • Histidine Decarboxylase / metabolism
  • Lactobacillus / classification
  • Lactobacillus / enzymology*
  • Molecular Sequence Data
  • Molecular Weight
  • Phylogeny
  • Plasmids / genetics*
  • Polymerase Chain Reaction
  • Sequence Analysis, DNA


  • Histamine
  • Histidine Decarboxylase