Project description:Pseudomonas putida KT2440 (KT2440) has been established as an industrially relevant chassis for the production of the jet-fuel precursor isoprenol. However, the wild type KT2440 strain consumed isoprenol as sole carbon source and its growth is inhibited by isoprenol, which is an impediment to high titer, rate, yield production. In this study, we investigated genes responsible for isoprenol catabolism and the stress responses of Pseudomonas putida via RNA-seq.
Project description:We analyzed gene expression during conjugative transfer of plasmid RP4. Pairs of rifampicin-susceptible (RifS) and -resistance (RifR) strains of Pseudomonas putida KT2440 were conjugated for 10 minute on filter membrane in the presence of rifampicin to discriminate the expression changes in the donor and recipient cells.
Project description:KaiC is the central cog of the circadian clock in Cyanobacteria. Close homologs of this protein are widespread among bacteria not known to have a circadian physiology. The function, interaction network, and mechanism of action of these KaiC homologs are still largely unknown. Here, we focus on KaiC homologs found in environmental Pseudomonas species. We characterize experimentally the only KaiC homolog present in Pseudomonas putida KT2440 and Pseudomonas protegens CHA0. Through phenotypic assays and transcriptomics, we show that KaiC is involved in osmotic and oxidative stress resistance in P. putida and in biofilm production in both P. putida and P. protegens.
Project description:The bacterium Pseudomonas putida KT2440 has the ability to reduce selenite forming nanoparticles of elemental selenium. This is the transcriptome of the organism when cultured in the presence of selenite.
Project description:Pseudomonas putida KT2440 (KT2440) has been established as an industrially relevant chassis for the production of the jetfuel precursor isoprenol. However, this strain assimilated isoprenol as sole carbon source and also showed impaired growth at isoprenol concentrations > 2 g/L which is a significant impediment to high TRY production. In this study, we used tolerization adaptive laboratory evolution and functional genomics to demonstrate improved growth of KT2440 strains in the presence of up to 8 g/L isoprenol. DNA sequencing of the evolved strains revealed mutations – a combination of SNPs and large deletions acquired in response to both isoprenol and a trace formaldehyde impurity. Mutations associated to isoprenol tolerance in the evolved isolates were specific to SNPs in the transcriptional regulators gnuR, xxxR and xxxR and two large deletions in the regions that also encoded the multidrug efflux pump TtgABC and certain phage proteins. Proteomic analysis of selected evolved strains implied a concerted detoxification process for isoprenol and formaldehyde even in the absence of the offending trace contaminant. The evolved strains also activated different pathways to enhanced tolerance. These included either upregulation of a global stringent response regulator SpoT in one or by the action of multiple alcohol and other dehydrogenases
