Analysis of a 30 kbp plasmid encoding histidine decarboxylase gene in Tetragenococcus halophilus isolated from fish sauce.
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.
National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa-ku, Yokohama 236-8648, Japan. msatomi@affrc.go.jp
Masataka
M
Satomi
Manabu
M
Furushita
Hiroshi
H
Oikawa
Miwako
M
Yoshikawa-Takahashi
Yutaka
Y
Yano
D001483:Base Sequence; D003001:Cloning, Molecular; D016000:Cluster Analysis; D005285:Fermentation; D005396:Fish Products / Q000382:microbiology*; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology*; D006632:Histamine / Q000096:biosynthesis*; D006640:Histidine Decarboxylase / Q000235:genetics* / Q000378:metabolism; D007778:Lactobacillus / Q000145:classification / Q000201:enzymology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D006632:Histamine; D006640:Histidine Decarboxylase