DISTRIBUTION OF THE CATABOLIC TRANSPOSON TN5271 IN A GROUNDWATER BIOREMEDIATION SYSTEM

The distribution of Tn5271-related DNA sequences in samples of groundw ater and a groundwater bioremediation system at the Hyde Park (Niagara Falls, N.Y.) chemical landfill site was investigated. PCR amplificati on of target sequences within the cba genes of Tn5271 revealed similar sequences in the groundwater community and in samples from the sequen cing batch reactors treating that groundwater. Cell dilution combined with PCR amplification indicated that cba sequences were carried in ab out 1 of 10 culturable bacteria from the treatment system. Characteriz ation of isolates involved in chlorobenzoate and toluene biodegradatio n in the treatment system indicated that two phenotypic clusters, Alca ligenes faecalis type 2 and CDC group IVC-2, contained all of the Tn52 71 probe-positive isolates from the community. These two groups differ ed phenotypically from recipient groups isolated following horizontal transfer of pBRC60 (Tn5271) in pristine freshwater microcosms. A genet ic rearrangement in Tn5271 attributable to the intramolecular transpos ition of the flanking element IS1071R was detected in an isolate from the treatment system. Comparison of the structure of the intramolecula r transposition derivative from groundwater isolate OCC13(pBRC13) with a laboratory-derived intramolecular transposition derivative of pBRC6 0 revealed similarities. The rearrangement was shown to increase the s tability of the plasmid under starvation conditions.