Project description:Here, we investigated the impact of Stx2 phage carriage on Escherichia coli (E. coli) K-12 MG1655 host gene expression. Using quantitative RNA-seq analysis, we compared the transcriptome of naïve MG1655 and the lysogens carrying the Stx2 phage of the 2011 E. coli O104:H4 outbreak strain or of the E. coli O157:H7 strain PA8, which share high degree of sequence similarity.
Project description:Phage-like elements are found in a multitude of streptococcal species, including pneumococcal strain Hungary19A-6 (SpnCI). The aim of our research was to investigate the role of phage-like element SpnCI in enhanced virulence and phenotypic modulation within Streptococcus pneumoniae. SpnCI was found to significantly enhance virulence within the invertebrate infection model Galleria mellonella. Infections with SpnCI led to a lower mean health score (1.6) and survival percentage (20%) compared to SpnCI null TIGR4 infections (3.85 mean health score and 50% survival). SpnCI remained integrated throughout growth, conferring greater sensitivity to UV irradiation. Change in transcriptional patterns occurred, including downregulation of operons involved with cell surface modelling in the SpnCI containing strain of TIGR4. Kanamycin-tagged SpnCI strain in Hungary19A-6 was inducible and isolated from lysate along with both annotated prophages. No phages were identified by PCR nor electron microscopy (EM) following induction of TIGR4 SpnCI∆strA suggesting helper-phage dependence for dissemination. EM of lysate showed typical siphoviridae morphology with an average capsid size of 60 nm. Two of sixty capsids were found to be smaller, suggesting SpnCI disseminates using a similar mechanism described for Staphylococcus aureus phage-like element SaPI. SpnCI from lysate infected capsule null strain T4R but was incapable of infecting the encapsulated TIGR4 strain suggesting that capsule impedes phage infection. Our work demonstrates that SpnCI can modulate virulence, UV susceptibility, alter transcriptional patterns, and furthermore, can disseminate via infection within pneumococcus. Further research is necessary to elucidate how SpnCI modulates virulence and what genes are responsible for the enhanced virulence phenotype.
Project description:Bacteriophages (phages) are widespread in Streptococcus pneumoniae, with most strains carrying phage genomes integrated into the chromosome. RNA sequencing was utilised to explore whether phage gene expression could be detected. The pneumococcal reference strain PMEN3 (Spain9V-3), which contained two full-length phages and one partial phage, was grown in broth culture and mitomycin C was added to facilitate phage induction. PMEN3 culture samples were taken at sequential time points and RNA was extracted and sequenced.
Project description:Comparison of Streptococcus pneumoniae D39 argR1 mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulon of the ArgR1 regulator under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011
Project description:Comparison of Streptococcus pneumoniae D39 ahrC mutant compared to D39 wild type in CDM with 10 mM arginine to define the regulon of the AhrC regulator under this condition. Details described in Kloosterman TG and Kuipers OP. ArgR1 and AhrC Mediate Arginine-Dependent Regulation of Arginine Acquisition- and Virulence Genes in the Human Pathogen Streptococcus pneumoniae. JBC 2011
