Project description:We used RNA-seq to conduct a genome-wide transcriptomic analysis of the C. difficile strain R20291 carrying the newly introduced ϕCD38-2 prophage. A total of 39 bacterial genes were differentially expressed in the R20291 lysogen, 26 of them being downregulated. Several of the regulated genes encode transcriptional regulators and PTS subunits involved in glucose, fructose and glucitol/sorbitol uptake and metabolism. Also of note, the presence of ϕCD38-2 upregulated the expression of a group of regulatory genes located in phi-027, a resident prophage common to most ribotype 027 isolates. The most differentially expressed gene was the conserved phase-variable cell wall protein CwpV, which was upregulated by about 20-fold in the lysogen. This is the first study describing the global response of C. difficile to the presence of a newly introduced prophage.
Project description:The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG). The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG).
Project description:We used RNA-seq to conduct a genome-wide transcriptomic analysis of the C. difficile strain R20291 carrying the newly introduced M-OM-^UCD38-2 prophage. A total of 39 bacterial genes were differentially expressed in the R20291 lysogen, 26 of them being downregulated. Several of the regulated genes encode transcriptional regulators and PTS subunits involved in glucose, fructose and glucitol/sorbitol uptake and metabolism. Also of note, the presence of M-OM-^UCD38-2 upregulated the expression of a group of regulatory genes located in phi-027, a resident prophage common to most ribotype 027 isolates. The most differentially expressed gene was the conserved phase-variable cell wall protein CwpV, which was upregulated by about 20-fold in the lysogen. This is the first study describing the global response of C. difficile to the presence of a newly introduced prophage. Two strains (WT and lysogen) were subjected for RNA-seq analysis with two biological replicates each.
Project description:Temperate bacteriophages (prophages) have recently been demonstrated in Campylobacter jejuni. However, what they do there is largely unknown. In the series of studies that are the subject of these submissions we have investigated the relative expression levels of proteins in C. jejuni isolates that differ in the presence or absence of the CJIE1 prophage. At the time of the initial investigations whole genome sequence data were not available for the isolates used, though DNA microarray data indicated that the isolates were very closely related. The overall project was carried out through four separate experiments. The first set of experiments (experiment 1) therefore compared protein expression in 4-plex iTRAQ experiments using three isolates carrying the (previously sequenced) prophage with a fourth isolate that was epidemiologically and genetically related to these isolates but which naturally lacked the CJIE1 prophage. Three replicate experiments were done. These isolates were grown on medium containing blood to obtain optimal growth and determine whether any differences were found. Three replicate experiments were done. However, since these growth conditions may not mimic in vivo growth of the organism the results may not be considered relevant or very interesting. Previous work in the scientific literature indicated that growth on medium lacking blood but containing sodium deoxycholate induced the expression of at least some proteins associated with virulence and provided data thought to be of relevance to the virulence of the bacterium. Therefore two isolates were chosen, one with and one without the CJIE1 prophage. Each of three replicates of a 4-plex iTRAQ experiment compared protein expression of the two isolates (00-2425 and 00-2426) after growth on Mueller-Hinton agar with and without 0.1% sodium deoxycholate. There was pretty good overlap between the proteins expressed in the first two experiments but, because all results were expressed as log2 change values, it was difficult to determine whether the expression of some proteins was completely absent in one or the other isolate. As well, protein expression overall showed quite extensive differences compared with the first experiment that we attributed to the lack of blood in the growth medium; we thought we might be seeing a response to limited iron as well. Finally, the response to the deoxycholate was extensive, and we wished to further explore this phenomenon as a means of determining or verifying what effects were due to the presence of the CJIE1 prophage and which were due to other differences. Further 4-plex iTRAQ experiments compared protein expression for each of isolate after growth on medium containing blood, without blood, without blood plus sodium deoxycholate, and without blood plus 2.5% Oxgall. Comparison of the results for isolate 00-2425 (with the CJIE1 prophage) and 00-2426 (without the prophage) identified a small number of proteins that could not be detected in one or the other isolate and allowed discrimination of the effects of the prophage from the responses to iron limitation and bile salt preparations. This dataset is associated with the first experiment, experiment 1, which compares C. jejuni isolates carrying the CJIE1 prophage (00-2425, 00-2538, 00-2544) with a very closely related isolate lacking the prophage (00-2426)
Project description:Temperate bacteriophages (prophages) have recently been demonstrated in Campylobacter jejuni. However, what they do there is largely unknown. In the series of studies that are the subject of these submissions we have investigated the relative expression levels of proteins in C. jejuni isolates that differ in the presence or absence of the CJIE1 prophage. At the time of the initial investigations whole genome sequence data were not available for the isolates used, though DNA microarray data indicated that the isolates were very closely related. The overall project was carried out through four separate experiments. In experiment 1, relative levels of protein expression of three isolates carryint the CJIE1 prophage were compared with one lacking the prophage after growth on Mueller-Hinton agar containing blood. Previous work in the scientific literature indicated that growth on medium lacking blood but containing sodium deoxycholate induced the expression of at least some proteins associated with virulence and provided data thought to be of relevance to the virulence of the bacterium. Therefore experiment 2 was done (previous submission) to evaluate in a single 4-plex iTRAQ experiment the effect of sodium deoxycholate on protein expression and whether the presence of the CJIE1 prophage had any effect. The third set of experiments (experiment 3) was done to consolidate the previous observations into a single experiment for a single strain. In three replicate experiments C. jejuni isolate 00-2425 was grown on Mueller Hinton (MH) agar base, MH agar + 10% blood, MH agar containing 0.1% sodium deoxycholate and, to further investigate the nature and extent of the bile response, MH agar containing 2.5% Oxgall.
Project description:Temperate bacteriophages (prophages) have recently been demonstrated in Campylobacter jejuni. However, what they do there is largely unknown. In the series of studies that are the subject of these submissions we have investigated the relative expression levels of proteins in C. jejuni isolates that differ in the presence or absence of the CJIE1 prophage. At the time of the initial investigations whole genome sequence data were not available for the isolates used, though DNA microarray data indicated that the isolates were very closely related. The overall project was carried out through four separate experiments. Previous work in the scientific literature indicated that growth on medium lacking blood but containing sodium deoxycholate induced the expression of at least some proteins associated with virulence and provided data thought to be of relevance to the virulence of the bacterium. The second set of experiments (experiment 2) compared protein expression in 4-plex iTRAQ experiments using two isolates grown on medium with and without 0.1% sodium deoxycholate to further explore the effects of the CJIE1 prophage, if any, on protein expression. Results from that experiment indicated that there was an unexpectedly large bile response, and that there were differences in expression from the first experiment that may be attributable to the presence of blood in the culture medium in the first experiment, compared with the use of medium without blood in the second experiment. Experiment 3 was therefore designed to compare protein expression of the CJIE1-carrying isolate 00-2425 after growth on medium containing blood, without blood, and without blood but with bile salts. In experiment 4 we grew isolate 00-2426, which lacks prophage CJIE1, on the same four media. The goals were to determine if the differences in protein expression (detection) were similar to those in isolate 00-2425 and if there were any differences that could be attributed to the presence or absence of the CJIE1 prophage.
Project description:Temperate bacteriophages (prophages) have recently been demonstrated in Campylobacter jejuni. However, what they do there is largely unknown. In the series of studies that are the subject of these submissions we have investigated the relative expression levels of proteins in C. jejuni isolates that differ in the presence or absence of the CJIE1 prophage. At the time of the initial investigations whole genome sequence data were not available for the isolates used, though DNA microarray data indicated that the isolates were very closely related. The overall project was carried out through four separate experiments. Previous work in the scientific literature indicated that growth on medium lacking blood but containing sodium deoxycholate induced the expression of at least some proteins associated with virulence and provided data thought to be of relevance to the virulence of the bacterium. The second set of experiments (experiment 2) therefore compared protein expression in 4-plex iTRAQ experiments using two isolates. Isolate 00-2425 carried the CJIE1 prophage while the second isolate, 00-2426, did not. Three replicate experiments were done. Each isolate was grown on Mueller Hinton agar base and Mueller Hinton agar containing 0.1% sodium deoxycholate.