The distinct genetic divergence and gene organisation patterns of these learn more catabolons suggest disparate evolutionary origins, [12]. In relation to the identification and characterisation of styrene linked

PACoA catabolons, several strain specific traits have been reported in Pseudomonas species studied to date. Comparative analyses of sty gene sequences from Pseudomonas putida CA-3, Pseudomonas fluorescens ST, Pseudomonas species Y2 and Pseudomonas sp VLB120 reveal a high degree of similarity in terms of percentage identity and structural organisation, [1]. However, functional characterisations in P. putida CA-3 and P. fluorescens ST have identified different regulatory profiles in relation to catabolite repression inducing carbon sources and nutrient limitation exposure [6, 7, 13, 14]. With respect to the PACoA catabolon, an essential phenylacetic acid uptake mechanism has previously been characterised in Pseudomonas

putida U, co-ordinately expressed with the catabolic genes [10]. In contrast, a recent proteomic analysis of styrene grown P. putida CA-3 cells indicated that phenylacetic acid transport gene products were not detected in styrene grown CA-3, despite the expression of all other PACoA catabolon proteins [15]. Bioinformatic analysis of PACoA catabolon gene organisation in 102 microbial genomes revealed repeated de novo clustering of the catabolic genes [3]. However, the authors suggested that recombination events and in situ gene replacements by interspecies gene transfer had produced PXD101 considerable diversity in both gene composition and operonic organisation in the pathways. In light of these findings the question arises as to whether the conserved catabolic function of the PACoA catabolon is subject to varied, host dependent regulatory influences in differing species. Elucidation of such host regulatory

influences may identify key flux control points for recombinant strain engineering strategies to optimise biotechnological outputs related to the pathways [9, 16–18]. In this study the Pseudomonas putida CA-3 genome was randomly mutagenised Thymidine kinase with a mini-Tn5 transposon and isolates screened for altered styrene and phenylacetic acid utilisation phenotypes in an effort to identify key regulatory influences acting on these catabolic pathways in this strain. Figure 1 Over view of styrene catabolism. Summary schematic of the major steps in styrene and phenylacetic acid degradation. Gene clusters have been grouped broadly in relation to function, while the arrows reflect common operons observed in Pseudomonads. However, it should be noted that PF-01367338 chemical structure significant variation in PaCoA catabolon gene organisation is seen in nature, such that a standard consensus schematic is not possible.