Characterization of a second ornithine decarboxylase isolated from Morganella morganii.
The genes involved in the putrescine formation by Morganella morganii were investigated because putrescine is an indicator of food process deterioration. We report here on the existence of a new gene for ornithine decarboxylase (ODC) in M. morganii. The sequenced 5,311-bp DNA region showed the presence of four complete and one partial open reading frame. Putative functions have been assigned to several gene products by sequence comparison with the proteins included in the databases. The third open reading frame (speC) encoded a 722-amino acid protein showing 70.9% identity to the M. morganii ODC previously characterized (SpeF). The speC gene has been expressed in Escherichia coli, resulting in ODC activity. The presence of a functional promoter (PspeC) located upstream of speC has been demonstrated. Quantitative real-time reverse transcription PCR assay was used to quantify expression of both M. morganii ODC-encoding genes, speC and speF, under different growth conditions. This assay allows us to identify SpeF as the inducible M. morganii ODC, since it was highly expressed in the presence of ornithine.
De Las Rivas
Blanca
B
Departamento de Microbiología, Instituto de Fermentaciones Industriales, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain.
González
Ramón
R
Landete
José María
JM
Muñoz
Rosario
R
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005798:Genes, Bacterial / Q000235:genetics; D008969:Molecular Sequence Data; D020613:Morganella morganii / Q000201:enzymology*; D016366:Open Reading Frames; D009955:Ornithine Decarboxylase / Q000235:genetics* / Q000302:isolation & purification; D011700:Putrescine / Q000032:analysis / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D009955:Ornithine Decarboxylase; D011700:Putrescine