High frequency of auxotrophy in clinical isolates of Proteus mirabilis harboring an R plasmid
Rev. bras. genét
; 17(4): 359-64, dez. 1994. tab, graf
Article
de En
| LILACS
| ID: lil-164705
Bibliothèque responsable:
BR1.1
ABSTRACT
We report a novel phenomenon of high genetic instability, related to auxotrophy, in strains of Proteus mirabilis. Among P. mirabilis strains harboring the R plasmid Kept in our laboratory collection, and some freshly isolated strians from clinical material, 54 per cent of the samples presented auxotrophy at frequencies higher than 10(-3). Prototrophic closes gave rise to auxotrophic ones at frequencies not explainable by the usual mutation mechanisms. The instability mainly affected the carbamoyl phosphate synthetase gene (car), which leads to a double requirement for arginine and uracil for growth in minimal medium. Other genes were also affected, at a lower frequency. The car mutation does not revert to prototrophy. A similar phenomenon of instability was induced in Escherichia coli strain HB 101 upon introduction of a drug-resistance plasmid from P. mirabilis. We have ruled out the hypothesis of a transposon in the generation of auxotrophy.
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Indice:
LILACS
Sujet Principal:
Proteus mirabilis
/
Facteurs R
/
Mutation
langue:
En
Texte intégral:
Rev. bras. genét
Thème du journal:
GENETICA
/
HISTOLOGIA
Année:
1994
Type:
Article