Identification of a catabolic transposon, Tn4371, carrying biphenyl and 4-chlorobiphenyl degradation genes in Alcaligenes eutrophus A5.
Alcaligenes eutrophus A5 catabolizes biphenyl to CO2 via benzoate and 4-chlorobiphenyl to 4-chlorobenzoate. In curing and conjugation experiments, the A5 endogenous 51-kb IncP1 plasmid pSS50 was found to be dispensable for biphenyl and 4-chlorobiphenyl catabolism. Transfer of the biphenyl- and 4-chlorobiphenyl-degrading phenotype by means of pSS50 was observed at a frequency of 10(-5) per transferred plasmid in matings of A5 with other A. eutrophus strains. Transconjugants harbor enlarged pSS50 derivatives which contain additional genetic information governing the oxidation of biphenyl and 4-chlorobiphenyl to benzoate and 4-chlorobenzoate and originating from the chromosome of strain A5. The following observations indicate that the catabolic genes reside on a 59-kb large transposon (Tn4371) for which a restriction map is presented. (i) Tn4371 transposes between different replicons and at different locations of the same replicon. (ii) Transposition was observed in a Rec- strain of A. eutrophus. (iii) Tn4371 transposes as a single, contiguous piece of DNA. Although an RP4::Tn4371 plasmid was stably maintained in different hosts, the plasmid conferred growth on biphenyl only when present in strains of A. eutrophus and in an Acinetobacter sp. strain.
Springael
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D
Laboratory of Genetics and Biotechnology, SCK/CEN-VITO, Mol, Belgium.
Kreps
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S
Mergeay
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M
D000421:Alcaligenes / Q000235:genetics* / Q000378:metabolism; D001713:Biphenyl Compounds / Q000378:metabolism*; D015139:Blotting, Southern; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D005798:Genes, Bacterial; D015394:Molecular Structure
D001713:Biphenyl Compounds; D004251:DNA Transposable Elements; C006983:4-chlorobiphenyl