Control experiments with P. putida CA-3 wild type and D7 strains carrying the pBBR1MCS-5 expression vector without insert, revealed that the growth profiles presented in Figure 2 were not affected by plasmid maintenance demands or antibiotic presence in the respective media, (results not shown). RT-PCR of PACoA catabolon genes in wild type P. putida

CA-3 and rpoN disrupted D7 mutant strains Despite a wealth of available sequence data on the diverse taxonomic distribution and genetic organisation of the PACoA catabolon genes, an extensive review of the existing literature by the authors failed to uncover any prior association between σ54 factors and functional promoters of the PACoA catabolon. selleck chemicals Alonso et al previously proposed 3 putative operons within the PACoA catabolon in Pseudomonas sp. strain Y2, associated with the genes for ring hydroxylation, β-oxidation like conversions and phenylacetic acid transport, respectively [20]. RpoN dependent transcriptional regulation GSK2245840 manufacturer was not proposed in the study. Representative gene targets from these proposed operons were therefore selected for Linsitinib clinical trial analysis of substrate dependent, transcriptional activation in wild type P. putida CA-3 and D7 mutant strains. The target genes selected encoded the PACoA ligase,

(paaF), an epoxidase subunit 1, (paaG), and the phenylacetate permease, (paaL). Figure 3 presents a composite image of RT-PCR results, necessitated by the similarity in target gene product sizes. However, the profiles presented accurately reflect those of the individual gels, and take account of variation in contrast levels. Transcriptional activation of the paaF and paaG genes was readily detected following growth of wild type P. putida CA-3 on styrene or phenylacetic acid, while the RT-PCR product for Dichloromethane dehalogenase paaL was markedly weaker, Figure 3. RT-PCR analysis of D7 mutant strains grown on styrene produced paaF and paaG transcript

profiles similar to wild type cells, however, paaL transcripts were not detectable in the mutant, Figure 3. The authors note that Nikodinovic et al did not detect the presence of PaaL in a recent proteomic analysis of styrene grown P. putida CA-3 cells, [15]. However, the stirred tank reactor growth conditions employed, with continuous feeding of NH4Cl to maintain a concentration above 400 mg/L, differed significantly from the batch studies conducted in this investigation. The authors have previously published findings on the significant impact growth conditions can have on the transcriptional regulation of catabolon genes, particularly as inorganic nutrient limitations arise, [21]. It is possible therefore that the low level transcription of paaL reported here during styrene growth may reflect growth conditions not encountered in the proteomic study. 16S rRNA gene RT-PCR indicated equivalent levels of cDNA synthesis in each of the samples.