Analysis and Manipulation of Plasmid-Encoded Pathways for the Catabolism of Aromatic Compounds by Soil Bacteria

Abstract

Soil and water bacteria in general, and members of the genus Pseudomonas in particular, exhibit a fascinating wealth of exotic properties not found in commensal and parasitic bacteria, such as Escherichia coli. They are, for example, able to degrade and use as sources of carbon and energy a wide range of organic compounds, including some that are quite noxious and otherwise biocidal (e.g., phenol). Moreover, soil bacteria are able to evolve rapidly new metabolic activities in response to changes in environmental conditions, e.g., to evolve new pathways for the degradation of synthetic industrial compounds (xenobiotics) such as pesticides, that are newly applied to the environment (1). The rapidity of evolution of new pathways is particularly surprising because many pathways, e.g. those for the catabolism of aromatic hydrocarbons, involve a large number of enzymatic steps and often more than twice that number of polypeptides (2). It is hardly surprising, therefore, that many catabolic pathways are specified by plasmids (3), elements known to be instrumental for rapid genetic change in bacteria (4).