Stability of mutations in a Sphingomonas strain.
Sphingomonas sp. strain RW1 is able to mineralise dibenzofuran and dibenzo-p-dioxin. Three mutants were constructed that could not use dibenzofuran or dibenzo-p-dioxin as a carbon source but were able to grow with the succeeding metabolites of the pathway. Two different mutagenic agents were applied, a chemical treatment with 1-methyl-3-nitro-1-nitrosoguanidine, resulting in mutants RW1-N6 and RW1-N7, and a biological insertion mutagenesis with the mini-Tn5 transposon pBSL118, resulting in mutant RW1-M3. Southern blot analysis and PCR experiments confirmed a single insertion of the mini-Tn5 into one of the genes coding for the oxygenase component of the dibenzofuran 4,4a-dioxygenase system. The genetic stability of these mutants was examined after growth with complex medium under nonselective conditions. All three mutants failed to revert to wild-type metabolic functions.
Bünz
P V
PV
Abteilung für Mikrobiologie, Universität Hamburg, Germany. buenz@mikrobiologie.uni-hamburg.de
Buck
M
M
Hebenbrock
S
S
Fortnagel
P
P
D015139:Blotting, Southern; D004251:DNA Transposable Elements; D016946:Gram-Negative Aerobic Rods and Cocci; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D016254:Mutagenesis, Insertional; D009154:Mutation / Q000187:drug effects / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011549:Pseudomonas / Q000235:genetics*
D004251:DNA Transposable Elements; D008769:Methylnitronitrosoguanidine