Indigenous organophosphate-degrading (opd) plasmid pCMS1 of Brevundimonas diminuta is self-transmissible and plays a key role in horizontal mobility of the opd gene

A fosmid library of the 66 kb indigenous organophosphate-degrading (opd) plasmid pCMS1 of Brevundimonas diminuta was tagged with mini-transposon EZTn5 <R6Kγori/KAN-2>, to determine its sequence using transposon-specific primers. The sequence revealed the presence of a number of tra genes suggesting their role in conjugal transfer of pCMS1. Consistent with the presence of the tra genes, the B. diminuta plasmid, pCMS1::tet, generated by replacing the opd gene with opd::tet, served as a donor for transferring pCMS1::tet into recipient strain Pseudomonas putida. The self-transmissibility of the opd-containing plasmid pCMS1 and the existence of identical opd genes on otherwise dissimilar plasmids suggests a probable role of indigenous opd plasmids like pCMS1 in transferring the opd gene among soil bacteria

The Organophosphate degradation (opd) island-borne esterase-induced metabolic diversion in Escherichia coli and its influence on p-nitrophenol degradation

In previous studies of the organophosphate degradation gene cluster we showed that expression of an open reading frame (orf306) present within the cluster in E. coli allowed growth on p-nitrophenol (PNP) as sole carbon source. We have now shown that expression of orf306 in E. coli causes a dramatic up-regulation in genes coding for alternative carbon catabolism. The propionate, glyoxylate and Methyl Citrate Cycle (MCC) pathway-specific enzymes are up regulated, along with hca (phenyl propionate) and mhp (hydroxy phenyl propionate) degradation operons. These hca and mhp operons play a key role in degradation of PNP, enabling E. coli to grow using it as sole carbon source. Supporting growth experiments, PNP degradation products entered central metabolic pathways and got incorporated into the carbon backbone. The protein and RNA samples isolated from E. coli (pSDP10) cells grown in C14 labelled PNP indicated incorporation of C14 carbon suggesting Orf306-dependent assimilation of PNP in E. coli cells