2 research outputs found
Gene organization of the ornithine decarboxylase-encoding region in Morganella morganii
[Aims] The production of putrescine is a relevant property related to food quality
and safety. Morganella morganii is responsible for putrescine production in
fresh fish decomposition. The aim of this study was to gain deeper insights
into the genetic determinants for putrescine production in M. morganii.[Methods and Results] The 6972 bp DNA region showed the presence of three
complete and two partial open reading frames all transcribed in the same direction.
The second and third genes putatively coded for an ornithine decarboxylase
(SpeF) and a putrescine–ornithine antiporter (PotE), respectively, and
constituted an operon. The speF gene has been expressed in Escherichia coli
HT414, an ornithine decarboxylase defective mutant, resulting in ornithine
decarboxylase activity. The genetic organization of the SpeF–PotE-encoding
region in M. morganii is different to that of E. coli and several Salmonella
species.[Conclusions] The speF gene cloned from M. morganii encodes a functional
ornithine decarboxylase involved in putrescine production. Phylogenetic tree
based on 16S rDNA showed that ornithine decarboxylase activity is not related
to a specific phylogenetic tree branch in Enterobacteriaceae.[Significance and Impact of the Study] The identification of the DNA region
involved in putrescine production in M. morganii will allow additional research
on their induction and regulation in order to minimize putrescine production
in foods.This work was supported by grant RM03-002 (INIA),
AGL2005-00470 (CICYT) and S-0505/AGR/000153
(CAM).Peer reviewe