Project description:The Escherichia coli strain Nissle 1917 (EcN) is used as a probiotic for the treatment of certain gastrointestinal diseases in several European and non-European countries. In vitro studies showed EcN to efficiently inhibit the production of Shiga toxin (Stx) by Stx producing E. coli (STEC) such as Enterohemorrhagic E. coli (EHEC). The occurrence of the latest EHEC serotype (O104:H4) responsible for the great outbreak in 2011 in Germany was due to the infection of an enteroaggregative E. coli by a Stx 2-encoding lambdoid phage turning this E. coli into a lysogenic and subsequently into a Stx producing strain. Since EHEC infected persons are not recommended to be treated with antibiotics, EcN might be an alternative medication. However, because a harmless E. coli strain might be converted into a Stx-producer after becoming host to a stx encoding prophage, we tested EcN for stx-phage genome integration. Our experiments revealed the resistance of EcN towards not only stx-phages but also against the lambda phage. This resistance was not based on the lack of or by mutated phage receptors. Rather the expression of certain genes (superinfection exclusion B (sieB) and a phage repressor (pr) gene) of a defective prophage of EcN was involved in the complete resistance of EcN to infection by the stx- and lambda phage. Obviously, EcN cannot be turned into a Stx producer. Furthermore, we observed EcN to inactivate phages and thereby to protect E. coli K-12 strains against infection by stx- as well as lambda-phages. Inactivation of lambda-phages was due to binding of lambda-phages to LamB of EcN whereas inactivation of stx-phages was caused by a thermostable protein of EcN. These properties together with its ability to inhibit Stx production make EcN a good candidate for the prevention of illness caused by EHEC and probably for the treatment of already infected people.
Project description:The choice between cell death (lysis) and viral dormancy (lysogeny) following bacteriophage infection serves as a founding paradigm for the emergence of cellular heterogeneity in a genetically uniform population. The determination of host fate arises through the stochastic transcription from multiple viral genomes present within each cell, but this activity remains hidden from empirical interrogation, which typically stops at the whole-cell level. Here we use parallel sequential fluorescence in situ hybridization (par-seqFISH), followed by spatial clustering of phage-encoded transcripts within each cell, to profile the transcriptional activity of individual phages during synchronized infection of Escherichia coli (E. coli) by bacteriophage lambda. At the whole-cell level, transcription kinetics capture the developmental choice between lysis and lysogeny, and further demonstrate that viral replication is required for the emergence of diverging fate decisions. Zooming in to the single-phage level illuminates an individuality of viral activity during infection. We find that, while cells pursuing lysogeny display consensus activity of all in-habiting phages, lytic cells may contain phages that exhibit lysogenic activity. These findings support an earlier suggestion that consensus among coinfecting phages is required for cell dormancy. More broadly, our results highlight the need to identify how whole-cell behavior emerges from the activity of physically distinct copies of the same genetic circuit.
Project description:Here we have developed a method that combines chromatin immunoprecipitation with next-generation sequencing (ChIP-Seq) and mathematical modeling to quantify RecA protein binding during the active repair of a single DSB in the chromosome of Escherichia coli. Examination of RecA binding during double-strand break repair in Escherichia coli
Project description:Primary objectives: The study investigates whether a Escherichia coli Nissle-suspenison has a (preventive) antidiarrheal effect in patients with tumors who are treated with chemotherapeutic schemes which are associated with increased occurances of diarrhea. Diarrhea caused by treatment are thought to be reduced in intensity and/or frequency by the treatment with Escherichia coli Nissle-Suspension.
Primary endpoints: Common toxicity criteria (CTC) for diarrhea
Project description:Bacteria deploy diverse antiphage defense systems, including small bioactive molecules providing protection at the multicellular level. DNA-intercalating anthracyclines such as daunorubicin exhibit broad antiphage activity, but the underlying mechanism had remained elusive. Here, we systematically screened the Escherichia coli BASEL phage collection to elucidate the mode of action of daunorubicin. We identified taxonomically distinct clusters of susceptible viral groups and demonstrate that daunorubicin blocks infection of T5-like phages (Markadamsvirinae) after first-step transfer (FST) as revealed by long-read sequencing. Continued expression of pre-early genes leads to abortive infection via ‘mutual destruction’, where both phage and host succumb. Analogous phenotypes of abortive infection were observed for taxonomically diverse phages with different DNA-intercalating antiphage molecules. Notably, we show that daunorubicin synergizes with downstream nucleic acid-targeting defences underscoring context dependency in the observed defense phenotype. Our findings reveal how chemical defense contributes to the multilayered antiviral immunity and highlight the intricate interplay between mechanistic inhibition and infection outcome.
Project description:The purpose of this study is to determine whether the presence of pathogenic Escherichia coli in colon is associated with psychiatric disorders.
Project description:Nucleic Acid Sequencing for the study of division induced double strand breaks in the terminus region of Escherichia coli cells lacking RecBCD DNA repair enzymes.
Project description:Multiple infection sources for enterohemorrhagic Escherichia coli O157:H7 are known, including food of animal origin and produce. The ecology of this pathogen outside its human host is largely unknown. One third of its annotated genes still are hypothetical. To identify genetic determinants expressed under environmental factors, we applied strand-specific RNA-sequencing of strain E. coli EDL933 under 11 different biotic and abiotic conditions: LB medium at pH4, pH7, pH9, or at 15°C; LB with nitrite or trimethoprim-sulfamethoxazole; LB-agar surface, M9 minimal medium, spinach leaf juice, surface of living radish sprouts, and cattle feces. Of 5379 annotated genes, only 144 are transcriptionally completely inactive under all conditions. Of 1,771 hypothetical genes, 1,672 exhibit significant transcriptional signals under at least one condition. The pathogenicity island LEE showed highest transcriptional activity in LB medium, minimal medium, and after treatment with antibiotics. Unique sets of genes, including many hypothetical genes, are highly up regulated on radish sprouts, cattle feces, or in the presence of antibiotics. For instance, azoR is biotechnologically important, but its environmental function has been elusive. This gene is highly active on radish sprouts. Further, we observed induction of the shiga-toxin carrying phages by antibiotics and confirmed active biofilm related genes on radish sprouts, in cattle feces, and on agar plates. Thus, environmental transcriptomics uncovers hitherto unknown gene functions and regulatory patterns of Escherichia coli O157:H7.
Project description:Multiple infection sources for enterohemorrhagic Escherichia coli O157:H7 are known, including food of animal origin and produce. The ecology of this pathogen outside its human host is largely unknown. One third of its annotated genes still are hypothetical. To identify genetic determinants expressed under environmental factors, we applied strand-specific RNA-sequencing of strain E. coli EDL933 under 11 different biotic and abiotic conditions: LB medium at pH4, pH7, pH9, or at 15°C; LB with nitrite or trimethoprim-sulfamethoxazole; LB-agar surface, M9 minimal medium, spinach leaf juice, surface of living radish sprouts, and cattle feces. Of 5379 annotated genes, only 144 are transcriptionally completely inactive under all conditions. Of 1,771 hypothetical genes, 1,672 exhibit significant transcriptional signals under at least one condition. The pathogenicity island LEE showed highest transcriptional activity in LB medium, minimal medium, and after treatment with antibiotics. Unique sets of genes, including many hypothetical genes, are highly up regulated on radish sprouts, cattle feces, or in the presence of antibiotics. For instance, azoR is biotechnologically important, but its environmental function has been elusive. This gene is highly active on radish sprouts. Further, we observed induction of the shiga-toxin carrying phages by antibiotics and confirmed active biofilm related genes on radish sprouts, in cattle feces, and on agar plates. Thus, environmental transcriptomics uncovers hitherto unknown gene functions and regulatory patterns of Escherichia coli O157:H7. Eleven different conditions were sequenced on the SOLiD system. Of two of the condtions, spinach medium and LB-nitrite, technical replicates were sequenced. Of LB medium and radish sprouts, biological replicates were sequenced on an Illumina MiSeq.