The aim of the project is to understand the enzymatic and genetic basis for the extraordinary biochemical versatility of the bacterium Pseudomonas cepacia (P. multivorans) and related species such as P. pickettii and P. marginata. As well as being especially suitable organisms for studies of the evolution and regulation of catabolic pathways these pseudomonads have attracted attention because they are opportunistic pathogens for man and cause diseases of economically important plants. Specific objectives of the proposed research are 1) to further define aspects of penicillin, glucose, and amino acid degradation in P. cepacia; 2) to examine the extent to which plasmids contribute to the nutritional versatility and antibiotic resistance of this and closely related pseudomonads; 3) to perfect a system of genetic analysis we have developed for P. cepacia based on plasmid mediated transfer of chromosomal genes and continue our efforts to develop a comparable system of transductional analysis and; 4) to further define a plasmid alteration we have detected in unusual lysine auxotrophs which have lost the wild type capacity to utilize penicillin as sole source of carbon, nitrogen, sulfur, and energy. The multiple loss of function in these mutants appears to be related to alteration of a 95 Mdal plasmid we have detected in the parent strain. Our working hypothesis, based on restriction enzyme analysis of plasmid DNA from the mutant and wild type strains, is that the mutational event is reorientation of an invertible element on the plasmid. The results represent a breakthrough in defining the roles of cryptic plasmids in P. cepacia and promise to lead to important information about the regulation of gene expression in this bacterium.