Project description:The marine bacterium Phaeobacter inhibens produces tropodithietic acid (TDA), a broad-spectrum antibiotic and anticancer agent. TDA allows P. inhibens to antagonize other bacteria, including several pathogens, and eukaryotes. Since recently antibiotics are also discussed to function as intermicrobial signals. Here we show that ~10% of the genes of P. inhibens are strongly influenced by N-acyl-homoserine lactone (AHL) mediated quorum sensing (QS), switching the bacteriumâs life style from attached to free-living. In an AHL negative mutant of P. inhibens subinhibitory concentrations of TDA caused the same regulatory effect as the AHL. This demonstrates that bacteria can produce antibiotic compounds not only as weapons, but also to substitute their endogenous AHL molecule in QS. The dual function of TDA probably supports the QS system to accelerate regulatory processes and points to a so far neglected role of antibiotics at subinhibitory concentrations in the environment and in microbial interactions. Comparison of whole transcriptomes of wildytype, quorum sensing mutants (pgaI and pgaR) and pgaI grown supplemented with subinhibitory concentration of the antibiotic TDA. RNA isolated in the late exponential growth phase. 4 biological replicates investigated for each strain.
Project description:The marine bacterium Phaeobacter inhibens produces tropodithietic acid (TDA), a broad-spectrum antibiotic and anticancer agent. TDA allows P. inhibens to antagonize other bacteria, including several pathogens, and eukaryotes. Since recently antibiotics are also discussed to function as intermicrobial signals. Here we show that ~10% of the genes of P. inhibens are strongly influenced by N-acyl-homoserine lactone (AHL) mediated quorum sensing (QS), switching the bacterium’s life style from attached to free-living. In an AHL negative mutant of P. inhibens subinhibitory concentrations of TDA caused the same regulatory effect as the AHL. This demonstrates that bacteria can produce antibiotic compounds not only as weapons, but also to substitute their endogenous AHL molecule in QS. The dual function of TDA probably supports the QS system to accelerate regulatory processes and points to a so far neglected role of antibiotics at subinhibitory concentrations in the environment and in microbial interactions.
Project description:Comparison of 3 yeast strains grown under nitrogen starvation, nitrogen rich conditions, with and without quorum sensing molecule 2-phenylethanol
Project description:The Pseudomonas synxantha strain NCIMB10586 produces the antibiotic mupirocin / Pseudomonic acid A from a 75 kb gene cluster; expression of this is regulated through quorum-sensing. We wished to examine expression of the strain during batch growth, in particular of the mupirocin cluster and any other operons regulated in a similar manner. We took samples from three independent cultures at 7 time-points - sampling every 2 hours from 6 to 18 hours.
