Molecular cloning and functional characterization of a histidine decarboxylase from Staphylococcus capitis.
OBJECTIVE
Histamine intoxication is probably the best known toxicological problem of food-borne disease. A histamine-producing Staphylococcus capitis strain has been isolated from a cured meat product. The aim of this study was to gain deeper insights into the genetic determinants for histamine production in Staph. capitis.


RESULTS
The nucleotide sequence of a 6446-bp chromosomal DNA fragment containing the hdcA gene encoding histidine decarboxylase (HDC) has been determined in Staph. capitis IFIJ12. This DNA fragment contains five complete and two partial open reading frames. Putative functions have been assigned to gene products by sequence comparison with proteins included in the databases. The hdcA gene has been expressed in Escherichia coli resulting in HDC activity. The presence of a functional promoter (Phdc) located upstream of hdcA has been demonstrated. Insertion of the histamine biosynthetic locus in Staph. capitis seems to be associated with a noticeable genome reorganization.


CONCLUSIONS
Among the staphylococcal species analysed in this study only Staph. capitis strains produce histamine. The hdcA gene cloned from Staph. capitis encodes a functional HDC that produce histamine from the amino acid histidine.


CONCLUSIONS
The identification of the DNA region involved in histamine production in Staph. capitis will allow further work in order to avoid histamine production in foods.
de las Rivas
B
B
Departamento de Microbiología, Instituto de Fermentaciones Industriales, CSIC, Madrid, Spain.
Rodríguez
H
H
Carrascosa
A V
AV
Muñoz
R
R
D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000378:metabolism; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology*; D015870:Gene Expression; D006632:Histamine / Q000633:toxicity*; D006640:Histidine Decarboxylase / Q000235:genetics* / Q000378:metabolism; D007763:Lac Operon; D008461:Meat Products / Q000382:microbiology*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013210:Staphylococcus / Q000201:enzymology*; D013212:Staphylococcus epidermidis / Q000235:genetics; D013552:Swine
D011993:Recombinant Fusion Proteins; D006632:Histamine; D006640:Histidine Decarboxylase