Project description:This project tested if siderophores are publig goods in Pseudomonas, and involved resequencing a well used siderophore mutant made by non-specific mutagenesis techniques
Project description:Siderophores are specialized molecules with different chemical structures, produced by bacteria and fungi to scavenge iron from the environment, a crucial nutrient for their growth and metabolism. These iron-chelating compounds enable bacteria to overcome iron limitation, a key factor in microbial survival and pathogenesis. Catecholate-type siderophores are primarily produced by bacteria, while hydroxamates are predominantly produced by fungi. The capacity of nine hydroxamate-type siderophores produced by fungi to serve as siderophores for iron acquisition by Pseudomonas aeruginosa, a human pathogen, has been investigated. Growth assays under iron limitation and 55Fe incorporation tests clearly highlighted that all nine siderophores promoted bacterial growth and facilitated iron transport. Additionally, the study aimed to identify the TonB-dependent transporters (TBDTs) responsible for iron import mediated by the tested siderophores. Mutant strains lacking genes encoding TBDTs were employed, revealing that iron is imported into P. aeruginosa cells solely by FpvB for the siderophores coprogen, triacetylfusarinine C, fusigen, ferrirhodin, and ferrirubin siderophores. Iron complexed by desferioxamine G is imported by two TBDTs, FpvB and FoxA. Ferricrocin-Fe and ferrichrycin-Fe complexes are imported by FpvB and FiuA. Lastly, rhodotorulic acid-Fe complexes are imported by FpvB, FiuA, and another unidentified TBDT. In conclusion, the data illustrate the effectiveness of hydroxamate-type siderophores in transporting iron into P. aeruginosa cells and provide insights into the intricate molecular mechanisms involved in iron acquisition, which have implications for understanding bacterial pathogenesis and developing potential therapeutic strategies.
Project description:Epithelial cells were in contact with bacteria supernatant during different times of incubation. time course supernatant 10 % MM39 Keywords: time-course
Project description:Each condition (cellular interaction with bacteria or with bacterial supernatant) was hybridized on 6 slides (3 slides, corresponding to different interactions and RNA extractions, were swapped). Keywords: parallel sample
Project description:Epithelial cells were in contact either with live bacteria (S. aureus) or with bacterial supernatant during 3 hours. Three dependant experiment for each condition were performed. RNA from epithelial cells were extracted. Each condition was hybridized on 6 slides (3 slides with their corresponding swap) Keywords: parallel sample
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:Each condition (cellular interaction with bacteria or with bacterial supernatant) was hybridized on 6 slides (3 slides, corresponding to different interactions and RNA extractions, were swapped).
Project description:Epithelial cells were in contact either with live bacteria (S. aureus) or with bacterial supernatant during 3 hours. Three dependant experiment for each condition were performed. RNA from epithelial cells were extracted. Each condition was hybridized on 6 slides (3 slides with their corresponding swap)
Project description:Bacterial immunotherapy holds promising cancer-fighting potential. However, unlocking its power requires a mechanistic understanding of how bacteria both evade antimicrobial immune defenses and stimulate antitumor immune responses within the tumor microenvironment (TME). Here, by harnessing an engineered Salmonella enterica strain with this dual proficiency, we unveiled a singular mechanism underlying. Specifically, the hysteretic nonlinearity of interleukin-10 receptor (IL-10R) expression drives tumor-infiltrated immune cells into a tumor-specific IL-10Rhi state. Bacteria leverage this to enhance tumor-associated macrophages producing IL-10, evade phagocytosis by tumor-associated neutrophils, and coincidently expand and stimulate the preexisting exhausted tumor-resident CD8+ T cells. This effective combination eliminated tumors, prevented recurrence, and inhibited metastasis across multiple tumor types. Analysis of human samples suggested that IL-10Rhi state might be a ubiquitous trait across human tumor types. Our study unveils the unsolved mechanism behind bacterial immunotherapy's dual challenge in solid tumors and provides a framework for intratumor immunomodulation.