Project description:Transcriptional profile of the rpoC G1122D mutant during log growth phase in LB medium. Bacillus subtilis W168, WT vs. rpoC (G1122D). The experiment was conducted two times using three independent total RNA preparations (biological triplicates). Each comparison was performed in dye-swap with the same RNA preparation. For each paried comparison, one sample was labeled with Alexa Fluor 555 and the other was with Alexa Fluor 647.
Project description:Transcriptional profile of the sigA (G336C) mutant during log growth phase in LB medium. Bacillus subtilis W168, WT vs. sigA (G336C). The experiment was conducted two times using three independent total RNA preparations (biological triplicates). Each comparison was performed in dye-swap with the same RNA preparation. For each paried comparison, one sample was labeled with Alexa Fluor 555 and the other was with Alexa Fluor 647.
Project description:Transcriptional profile of the rocG gudB double null mutant during log growth phase in LB medium. Bacillus subtilis W168, WT vs. delta-rocG delta-gudB. The experiment was conducted two times using three independent total RNA preparations (biological triplicates). For each paried comparison, WT was labeled with Alexa Fluor 555 and the rocG gudB double mutant was with Alexa Fluor 647.
Project description:Transcriptional profile of the uppS-RBS (A to C) mutant during log growth phase in LB medium. Bacillus subtilis W168, WT vs. uppS-RBS (A to C). The experiment was conducted two times using three independent total RNA preparations (biological triplicates). Each comparison was performed in dye-swap with the same RNA preparation. For each paried comparison, one sample was labeled with Alexa Fluor 555 and the other was with Alexa Fluor 647.
Project description:S. typhimurium 14028 wt, hfq and smpB were harvested from log phase LB (LBlog); (2), stationary phase LB (LBstat); (3) 4h MgM medium pH 5.0 after resuspension of LB stat culture (MgMshock); and (4) log phase MgM medium pH5.0 after 100fold dilution of an LB stat culture (MgMDil). Total RNA was extracted, cDNA labeled and hybridized to a non-redundant Salmonella whole genome PCR product ORF array.
Project description:BackgroundSubtilin is a peptide antibiotic (lantibiotic) natively produced by Bacillus subtilis ATCC6633. It is encoded in a gene cluster spaBTCSIFEGRK (spa-locus) consisting of four transcriptional units: spaS (subtilin pre-peptide), spaBTC (modification and export), spaIFEG (immunity) and spaRK (regulation). Despite the pioneer understanding on subtilin biosynthesis, a robust platform to facilitate subtilin research and improve subtilin production is still a poorly explored spot.ResultsIn this work, the intact spa-locus was successfully integrated into the chromosome of Bacillus subtilis W168, which is the by far best-characterized Gram-positive model organism with powerful genetics and many advantages in industrial use. Through systematic analysis of spa-promoter activities in B. subtilis W168 wild type and mutant strains, our work demonstrates that subtilin is basally expressed in B. subtilis W168, and the transition state regulator AbrB strongly represses subtilin biosynthesis in a growth phase-dependent manner. The deletion of AbrB remarkably enhanced subtilin gene expression, resulting in comparable yield of bioactive subtilin production as for B. subtilis ATCC6633. However, while in B. subtilis ATCC6633 AbrB regulates subtilin gene expression via SigH, which in turn activates spaRK, AbrB of B. subtilis W168 controls subtilin gene expression in SigH-independent manner, except for the regulation of spaBTC. Furthermore, the work shows that subtilin biosynthesis in B. subtilis W168 is regulated by the two-component regulatory system SpaRK and strictly relies on subtilin itself as inducer to fulfill the autoregulatory circuit. In addition, by incorporating the subtilin-producing system (spa-locus) and subtilin-reporting system (PpsdA-lux) together, we developed "online" reporter strains to efficiently monitor the dynamics of subtilin biosynthesis.ConclusionsWithin this study, the model organism B. subtilis W168 was successfully established as a novel platform for subtilin biosynthesis and the underlying regulatory mechanism was comprehensively characterized. This work will not only facilitate genetic (engineering) studies on subtilin, but also pave the way for its industrial production. More broadly, this work will shed new light on the heterologous production of other lantibiotics.
Project description:Abstract of associated manuscript: Daptomycin is the first of a new class of cyclic lipopeptide antibiotics used against multidrug-resistant Gram-positive pathogens. The proposed mechanism of action involves disruption of the functional integrity of the bacterial membrane in a Ca2+-dependent manner. We have used transcriptional profiling to demonstrate that treatment of Bacillus subtilis with daptomycin strongly induces the lia operon including the autoregulatory LiaRS two-component system (homologous to Staphylococcus aureus VraSR). The lia operon protects against daptomycin and deletion of liaH, encoding a phage shock protein A (PspA)-like protein, leads to 3-fold increased susceptibility. Since daptomycin interacts with the membrane, we tested mutants with altered membrane composition for effects on susceptibility. Deletion mutations of mprF (lacking lysyl-phosphatidylglycerol) or des (lipid desaturase) increased daptomycin susceptibility, whereas overexpression of MprF decreased susceptibility. Conversely, depletion of the cell for the anionic lipid phosphatidylglycerol led to increased resistance. Fluorescently-labeled daptomycin localized to the septa and in a helical pattern around the cell envelope and was delocalized upon depletion of phosphatidylglycerol. Together, these results indicate that the daptomycin-Ca2+ complex interacts preferentially with regions enriched in anionic phospholipids and leads to membrane stresses that can be ameliorated by PspA family proteins.