The clc element of Pseudomonas sp strain B13 and other mobile degradative elements employing phage-like integrases

Genes for metabolic pathways in bacteria that degrade aromatic or aliphatic pollutants have mostly been confined to either plasmid DNAs or to the chro mosome. For a few pathways, including classical pathways for chlorocatechol and biphenyl degradation, recent evidence has been obtained for location o f the pathway genes on mobile DNA elements which employ phage-like integras es. This enables the DNA elements to integrate into specific sites on the c hromosome and yet to excise and transfer to other host bacteria. This mini- review gives an overview of those elements and their relationship to an inc reasing number of phage-like elements associated with bacterial virulence.