Project description:The effect of lanthanum concentration and the effect of different lanthanide elements on gene expression and growth was tested in P. alloputida KT2440. Gene expression analysis was based on high-throughput RNAseq starting from rRNA-depleted samples, followed by determining differentially expressed genes.
Project description:Pseudomonas alloputida KT2440 (previously misclassified as P. putida KT2440 based on 16S rRNA gene homology) has emerged as an ideal host strain for plan t biomass valorization. However, P. alloputida KT2440 is unable to natively utilize abundant pentose sugars (e.g., xylose and arabinose) in hydrolysate streams, which may account for up to 25% of lignocellulosic biomass. In the last decades, microbes have been engineered to utilize the pentose sugars. However, most of the engineered strains were either slow-growing or displayed phenotypes that could not be replicated. In this work, we successfully isolated five Pseudomonas species with the native capability to utilize glucose, xylose and p-coumarate as a sole carbon source. These isolates were in two clusters; one set of isolates (M2 and M5) and the second set of isolates (BP6 and BP7) showed 85.6% and 96.2% ANI, respectively, to P. alloputida KT24440. BP8 showed 84.6% ANI to P. putida KT2440 and does not belong to any neighboring type strains indicating a new species. Notably, the isolates showed robust growth solely on xylose and higher growth rates (m, 0.36-0.49 h-1) when compared to only known xylose-utilizing Pseudomonas taiwanenesis VLB120 (m, 0.28 h-1) as a control. Unexpectedly, among five isolates, M2 and M5 grew solely on arabinose as well. Comprehensive analysis of genomics, transcriptomics and proteomics revealed the isolates utilize xylose and arabinose via Weimberg pathway (xylD-xylX-xylA) and oxidative pathway (araD-araX-araA), respectively. Furthermore, a preliminary result demonstrated the production of flaviolin solely on xylose and arabinose in the isolate, showing noteworthy potential to be an alternative host for lignocellulosic feedstocks into valuable products. This is the first report on isolating Pseudomonas strains natively capable of utilizing all of the major carbon sources in lignocellulosic biomass, and leading to higher consumption of available substrates and therefore maximizing the product yield.
Project description:Pseudomonas aeruginosa is an opportunistic pathogen which causes acute and chronic infections that are difficult to treat. Comparative genomic analysis has showed a great genome diversity among P. aeruginosa clinical strains and revealed important regulatory traits during chronic adaptation. While current investigation of epigenetics of P. aeruginosa is still lacking, understanding the epigenetic regulation may provide biomarkers for diagnosis and reveal important regulatory mechanisms. The present study focused on characterization of DNA methyltransferases (MTases) in a chronically adapted P. aeruginosa clinical strain TBCF10839. Single-molecule real-time sequencing (SMRT-seq) was used to characterize the methylome of TBCF. RCCANNNNNNNTGAR and TRGANNNNNNTGC were identified as target motifs of DNA MTases, M.PaeTBCFI and M.PaeTBCFII, respectively.
Project description:Purpose of study was to investigate whole genome expression changes of a strain with deletion of the two-component system TctD-TctE and determine genes dysregulate relative to the parental wildtype to gain insight into possible regulatory targets of TctD-TctE. TctD-TctE is a two-component system in Pseudomonas aeruginosa that responds to and regulates uptake of tricarboxylic acids such as citric acid. It accomplishes this through derepression of the porin encoding the gene opdH, thereby regulating influx of citrate metabolites from the surrounding environment. Deletion of the tctED operon (ΔtctED) resulted in a reduced growth phenotype when citric acid is present in media. In the ΔtctED strain the presence of citric acid was found to have an inhibitory effect on growth. When the alternative carbon source arginine was present, wildtype levels of growth could not be restored. Static cultures of ΔtctED had low cell density in the presence of citric acid but maintained the same levels of biofilm formation compared to conditions when no citric acid was present. This suggests a dysregulation of biofilm formation in the presence of citric acid. In the ΔtctED strain there was also greater accumulation of tobramycin within the biofilm compared to the PA14 wildtype strain. Additionally, analysis of whole-genome expression found that multiple metabolic genes were dysregulated in ΔtctED. Here it is concluded that TctD-TctE is involved in biofilm tolerance to tobramycin in the presence of citrate metabolites.
Project description:Indole-3-acetic acid (IAA), knows as common plant hormone, is one of the most distributed indole derivatives in the environment. A novel strain, which was able to use IAA as sole source of carbon and nitrogen, was isolated from farm soil, identified and classified as Pseudomonas composti LY1 based on 16S rRNA sequence and genome analysis. The optimal growth conditions for LY1 with IAA are characterized. Proteome profile of strain LY1 to IAA and citrate were analyzed and compared using label free strategy with LC-MS/MS.
Project description:This study evaluates the transcriptome of Arabidopsis thaliana infected with the Pseudomonas syringae strain DC3000 cor- carrying the type three secretion system effector HopBB1