Project description:P. aeruginosa PAO1 PA2663-UW expression in biofilm cells relative to P. aeruginosa PAO1 WT-UW expression in biofilm cells. All samples cultured in LB with glass wool. Keywords: Mutation
Project description:Pseudomonas aeruginosa PAO1 contacted with and without poplar roots gene expression Poplar contacted with and without PAO1 gene expression. All samples cultured in 1 x hrp + 0.25 % sucrose Experiment Overall Design: Strains: P. aeruginosa PAO1 WT Experiment Overall Design: Medium: 1 x hrp + 0.25 % sucrose Experiment Overall Design: Biofilm grown on poplar root compared to biofilm grown on glasswool Experiment Overall Design: Poplar roots grown
Project description:P. aeruginosa PAO1 wild type and PA2663 mutant strains expression in biofilm cells relative to P. aeruginosa PAO1 wild type strain expression in biofilm cells. All samples cultured in LB with glass wool Keywords: Biofilm
Project description:Biofilms are ubiquitous in natural, medical, and engineering environments. While most antibiotics that primarily aim to inhibit cell growth may result in bacterial drug resistance, biofilm inhibitors do not affect cell growth and there is less chance of developing resistance. This work sought to identify novel, non-toxic and potent biofilm inhibitors from Streptomyces bacteria for reducing the biofilm formation of Pseudomonas aeruginosa PAO1. Out of 4300 Streptomyces strains, one species produced and secreted peptide(s) to inhibit P. aeruginosa biofilm formation by 93% without affecting the growth of planktonic cells. Global transcriptome analyses (DNA microarray) revealed that the supernatant of the Streptomyces 230 strain induced phenazine, pyoverdine, and pyochelin synthesis genes. Electron microscopy showed that the supernatant of Streptomyces 230 strain reduced the production of polymeric matrix in P. aeruginosa biofilm cells, while the Streptomyces species enhanced swarming motility of P. aeruginosa. Therefore, current study suggests that Streptomyces bacteria are an important resource of biofilm inhibitors as well as antibiotics.
Project description:Biofilm formation by Pseudomonas aeruginosa relies on specific changes in gene expression. Some of these genes, for instance, control antibiotic resistance. We used microarrays to detail the global programme of gene expression underlying biofilm formation and identified distinct classes of up-regulated genes during this process. Pseudomonas aeruginosa PAO1 cells were grown as planktonic cells in LB broth for 4 hours (PC4) or 24 hours (PC24) and sessile cels for 24 hours.
Project description:Pseudomonas aeruginosa is an opportunistic pathogen that can cause severe infections in immunocompromised individuals, such as patients with cystic fibrosis where it commonly forms biofilms. Ciprofloxacin is used extensively to treat P. aeruginosa infections, but its effectiveness can be significantly reduced due to biofilm formation. Although many individual genes associated with biofilm formation have been characterised, the genetic basis of P. aeruginosa biofilm fitness related to antibiotics challenge remain unexplored. In this study we employed a high-density TraDIS-Xpress library of P. aeruginosa PAO1 to assay the impact of gene disruptions or altered gene expression on biofilm formation at different concentrations of ciprofloxacin. Gene fitness was analysed by comparing the biofilm samples to planktonic samples harvested at 12h, 24h and 48h with and without ciprofloxacin. Gene determinants of survival for biofilms at different stages of maturity in the presence and absence of ciprofloxacin were identified.
Project description:Chronic infections with Pseudomonas aeruginosa are a leading cause of morbidity and mortality in persons with cystic fibrosis (pwCF). P. aeruginosa persists in the CF lung by utilizing adaptation strategies to cause infection, including altering the expression of metabolic genes to acquire nutrients that are abundant in the CF airway. Glycerol in the airway is imported and metabolized by the glp regulon, which is under the control of the GlpR repressor. It has been shown that the loss of GlpR results in increased biofilm development in P. aeruginosa CF isolate compared to a wound isolate. Based on the increased biofilm phenotype observed and because biofilms are associated with increased antibiotic tolerance, we questioned whether GlpR plays a role in mediating antibiotic resistance of P. aeruginosa. We measured tobramycin tolerance in wild-type and glpR-defective P. aeruginosa isolates from the CF airway (FRD1) and a wound (PAO1). Cultures were grown in lysogeny broth or synthetic cystic fibrosis sputum consisting of the base formula of primarily amino acids (SCFM1) or supplemented with mucins and DNA (SCFM2), with dose-dependent concentrations of tobramycin. We tested the impact of a glpR mutation on P. aeruginosa adherence on bronchial epithelial cells from pwCF (CFBE) in the presence of tobramycin. CFBE cells were inoculated at an MOI of ~1:20 for 1 hour, given fresh apical media for 5 more hours, then apical and basal media was replaced with media containing 20 µg/ml tobramycin. We measured colony forming units (CFUs) and lactate dehydrogenase (LDH) release for cytotoxicity. Loss of glpR increased tolerance to tobramycin in both the PAO1 and FRD1 backgrounds in vitro at a concentration of 0.625 µg/mL in lysogeny broth and SCFM1. On both CFBE’s and 16HBE’s, the antibiotic resistance phenotype was more prominent in FRD1 glpR with a 2-log increase in viable bacteria when grown on cells and treated with 20 ug/ml tobramycin. However, changes in cytotoxicity where not observed between wildtype and GlpR mutants as LDH measurements were not significantly different. Our results indicate that GlpR may regulate antibiotic tolerance, in addition to biofilm development and glycerol metabolism. Additional studies are necessary to determine the mechanism of how GlpR modulates biofilm development and antibiotic tolerance.
Project description:Analysis of Pseudomonas aeruginosa PAO1 treated with 200 µM sphingomyelin. Results provide insight into the response to sphingomyelin in P. aeruginosa.