Project description:Here, we report the draft genome sequence of Pseudomonas sp. strain FEN, a nonfluorescent siderophore producer that was isolated from the Schlöppnerbrunnen fen, which is characterized by high concentrations of Fe, dissolved organic matter (DOM), and Fe-DOM complexes. This draft genome sequence provides insight into the mechanisms of siderophore biosynthesis and siderophore-mediated iron uptake by this bacterium.
Project description:Bacteria access iron, a key nutrient, by producing siderophores or using siderophores produced by other microorganisms. The pathogen Pseudomonas aeruginosa produces two siderophores but is also able to pirate enterobactin (ENT), the siderophore produced by Escherichia coli. ENT-Fe complexes are imported across the outer membranes of P. aeruginosa by the two-outer membrane transporters PfeA and PirA. Iron is released from ENT in the P. aeruginosa periplasm by hydrolysis of ENT by the esterase PfeE. We show here that pfeE gene deletion renders P. aeruginosa unable to grow in the presence of ENT because it is unable to access iron via this siderophore. Two-species co-culture under iron-restricted conditions show that P. aeruginosa strongly represses the growth of E. coli as long it is able to produce its own siderophores. Both strains are present in similar proportions in the culture as long as the siderophore-deficient P. aeruginosa strain is able to use ENT produced by E. coli to access iron. If pfeE is deleted, E. coli has the upper hand in the culture and P. aeruginosa growth is repressed. Overall, these data show that PfeE is the Achilles heel of P. aeruginosa in communities with bacteria producing ENT.
Project description:This study aims at investigating the ability of Pseudomonas aeruginosa to detect the presence of siderophore-antibiotic conjugates in an epithelial cell infection assay. We show that the presence of siderophore-antibiotic conjugates induces the transcription and expression of their corresponding transporters, indicating the bacteria are able to sense the chelators in their environment and adapt their phenotype accordingly.
Project description:Pseudomonas aeruginosa is known to tolerate antibiotic therapy during infection. This prevents clearance of infection and negatively impacts patient outcomes. Here, we report the transcriptome sequence of antibiotic-treated and untreated P. aeruginosa cultures and the differential gene expression observed when treated cells are compared to untreated cells.
Project description:Pseudomonas aeruginosa is a common nosocomial pathogen which produces siderophores to solubilize and transport chelated Fe3+ to aid its survival in both the environment and the host. However, there is a lack of comprehensive understanding regarding the molecular mechanisms underlying siderophore synthesis, uptake, and regulation within various ecological niches. In this study, we demonstrated that the BfmRS two-component system, part of the core genome of P. aeruginosa, plays a crucial role in siderophore metabolism. We have identified BfmS as an osmosensing histidine kinase that responds to external osmolytes, then modulates the activation of the response regulator BfmR. Under high osmolality, BfmR could directly bind to the promoters of pvd, fpv, and femARI gene clusters, thereby enhancing their expression and promoting siderophore metabolism. The proteomic and phenotypic analyses confirmed that deletion of bfmRS results in reduced expression levels of siderophore-related proteins as well as siderophore production. Importantly, loss of bfmR or bfmS significantly impaired bacterial survival in both iron deficiency medium and mouse lung infection models. Furthermore, phylogenetic analysis revealed that BfmRS is highly conserved and widely distributed across Pseudomonas species, evidences also proved that the BfmR of P. putida KT2440 and P. sp. MRSN12121 activated siderophore genes in response to high osmolality. Overall, this study sheds light on the previously unexplored signal transduction pathway, BfmRS, which governs the siderophore regulation in Pseudomonas species through perceiving an osmotic upshift. Considering that siderophores serve as unique social mediators, our findings contribute to a better understanding of how siderophores facilitate bacterial interactions with their eukaryotic hosts and contribute to the establishment of stable communities.
Project description:M. oryzae 70-15 was treated with multiple bacteria which inhibit 70-15's growth. The bacterial treatments were EA105, a pseudomonad naturally isolated from rice soil, as well as P. fluorescens biocontrol strain CHAO and the cyanide non-producing mutant of CHAO, CHA77.
Project description:A special immune system exists at distinct respiratory epithelium to combat invasion by Pseudomonas aeruginosa (PAO1). This study aimes to determine if interleukin-17C (IL-17C) is correlated with acute PAO1 infection in human nasal epithelium and to prove the role of IL-17C on iron sequestration during PAO1 infection. IL-17C has antipseudomonal effect by lowering iron sequestration and reducing siderophore activity. IL-17C could be efficient mediator to control PAO1 infection in human nasal epithelium.