Mutants d'Escherichia coli K 12 affectés pour leur croissance sur méthyl-β-D-glucuronide: Localisation du gène de structure de la β-D-glucuronidase (uid A)

Mutants of E. coli K 12 unable to grow on a β-D-glucuronide (methyl-β-D-glucuronide) and yet able to grow on hexuronates have been isolated; they are deficient for the enzyme: β-D-glucuronidase. By conjugation and transduction experiments, these mutations have been mapped in a locus uid A between man and aro D. No or weak cotransduction is found between aro and man: man is shifted from its precedent location to 30.5 minute very close to uid A (linked by 83 to 97% of cotransduction). The order of loci in this region appears to be: ... phe S...pps...aro D...uid A...man.... Some of these mutations can reverse to wild type with a thermosensitive glucuronidase. These reverse mutations are found linked to this locus uid A; these results strongly suggest that uid A is the site of the structural gene of β-glucuronidase.