Project description:In order to study the function of the Campylobacter jejuni Cj0667 gene, a series of experiments were carried out. Two strains were constructed: a Cj0667 knockout strain and a strain with a second copy over-expressing Cj0667 from an fdxA promoter. The transcriptomes of these were all compared to the wild-type strain. The arrays are all from RNA isolated in mid-exponential growth. Batch cultures of Campylobacter jejuni NCTC 11168 were grown in 50 ml volumes of Brucella broth in 70cm tissue culture flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (5% Oxygen, 10% Carbon dioxide, 85% Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 37 M-BM-:C. RNA was extracted from C. jejuni cultures grown to an OD600 of approximately 0.4. Briefly, 0.1 volume of 5% phenol in ethanol was mixed with the broth culture, and after centrifugation RNA was isolated with Tri Reagent (Sigma) and chloroform. RNA was further purified using the RNeasy kit (Qiagen) according to the manufacturerM-bM-^@M-^Ys instructions. The RNA was treated with Turbo DNA-free (Ambion) to remove any residual DNA according to the manufacturerM-bM-^@M-^Ys instructions. RNA concentration was determined using the Nanodrop Spectrophotometer NS-1000 (Thermo Scientific). RNA preparations of each sample type were labelled and hybridized to custom-designed Agilent microarrays. Equal quantities of RNA from test and control cultures were labelled by using nucleotide homologues of dUTP containing either Cy3 or Cy5 fluorescent dye (Perkin Elmer). For each microarray slide, the test strain was labelled with Cy3-dUTP, while the wild-type sample was labelled with Cy5-dUTP. RNA (15 M-BM-5g) was primed with 5 M-BM-5g pd(N)6 random hexamers (Amersham Biosciences). The Affinity Script kit (GE Healthcare) was used to produce cDNA, and hybridized (Agilent Hi-RPM Gene Expression Hybridization Kit) to the microarray slide according to the manufacturerM-bM-^@M-^Ys instructions. Microarrays were scanned at 5 M-BM-5m using an Axon 4000A scanner, and images were acquired using GenePix Pro 3.0 software (Axon). Related analysis reference: Holmes K., Mulholland F., Pearson B. M., Pin C., McNicholl-Kennedy J., Ketley J. M., Wells J. M. (2005) Campylobacter jejuni gene expression in response to iron limitation and the role of Fur Microbiology-SGM 151 243-257 (PMID 15632442).

Project description:In order to study the function of the Campylobacter jejuni Cj0138 gene, a series of experiments were carried out. Three strains were constructed: a Cj0138 knockout strain, a strain where the Cj0138 knockout was complemented in trans, and a strain with a second copy over-expressing Cj0138 from an fdxA promoter. The transcriptomes of these were all compared to the wild-type strain. The arrays are all from RNA isolated in mid-exponential growth from independent biological replicates. Batch cultures of Campylobacter jejuni NCTC 11168 were grown in 50 ml volumes of Brucella broth in 70cm tissue culture flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (5% Oxygen, 10% Carbon dioxide, 85% Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 37 M-BM-:C. RNA was extracted from C. jejuni cultures grown to an OD600 of approximately 0.4. Briefly, 0.1 volume of 5% phenol in ethanol was mixed with the broth culture, and after centrifugation RNA was isolated with Tri Reagent (Sigma) and chloroform. RNA was further purified using the RNeasy kit (Qiagen) according to the manufacturerM-bM-^@M-^Ys instructions. The RNA was treated with Turbo DNA-free (Ambion) to remove any residual DNA according to the manufacturerM-bM-^@M-^Ys instructions. RNA concentration was determined using the Nanodrop Spectrophotometer NS-1000 (Thermo Scientific). RNA preparations of each sample type were labelled and hybridized to custom-designed Agilent microarrays. Equal quantities of RNA from test and control cultures were labelled by using nucleotide homologues of dUTP containing either Cy3 or Cy5 fluorescent dye (Perkin Elmer). For each microarray slide, the test strain was labelled with Cy3-dUTP, while the wild-type sample was labelled with Cy5-dUTP. RNA (15 M-BM-5g) was primed with 5 M-BM-5g pd(N)6 random hexamers (Amersham Biosciences). The Affinity Script kit (GE Healthcare) was used to produce cDNA, and hybridized (Agilent Hi-RPM Gene Expression Hybridization Kit) to the microarray slide according to the manufacturerM-bM-^@M-^Ys instructions. Microarrays were scanned at 5 M-BM-5m using an Axon 4000A scanner, and images were acquired using GenePix Pro 3.0 software (Axon). Related analysis reference: Holmes K., Mulholland F., Pearson B. M., Pin C., McNicholl-Kennedy J., Ketley J. M., Wells J. M. (2005) Campylobacter jejuni gene expression in response to iron limitation and the role of Fur Microbiology-SGM 151 243-257 (PMID 15632442).

Project description:In order to study the function of the Campylobacter jejuni Cj1103 gene, a series of experiments were carried out. Three strains were constructed: a Cj1103 knockout strain, a strain where the Cj1103 knockout was complemented in trans, and a strain with a second copy over-expressing Cj1103 from an metK promoter. The transcriptomes of these were all compared to the wild-type strain. The arrays are all from RNA isolated in mid-exponential growth from independent biological replicates. Batch cultures of Campylobacter jejuni NCTC 11168 were grown in 50 ml volumes of Brucella broth in 70cm tissue culture flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (5% Oxygen, 10% Carbon dioxide, 85% Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 37 M-BM-:C. RNA was extracted from C. jejuni cultures grown to an OD600 of approximately 0.4. Briefly, 0.1 volume of 5% phenol in ethanol was mixed with the broth culture, and after centrifugation RNA was isolated with Tri Reagent (Sigma) and chloroform. RNA was further purified using the RNeasy kit (Qiagen) according to the manufacturerM-bM-^@M-^Ys instructions. The RNA was treated with Turbo DNA-free (Ambion) to remove any residual DNA according to the manufacturerM-bM-^@M-^Ys instructions. RNA concentration was determined using the Nanodrop Spectrophotometer NS-1000 (Thermo Scientific). Two or three independent RNA preparations (biological replicates) of each sample type were labelled and hybridized to custom-designed Agilent microarrays. Equal quantities of RNA from test and control cultures were labelled by using nucleotide homologues of dUTP containing either Cy3 or Cy5 fluorescent dye (Perkin Elmer). For each microarray slide, the test strain was labelled with Cy3-dUTP, while the wild-type sample was labelled with Cy5-dUTP. RNA (15 M-BM-5g) was primed with 5 M-BM-5g pd(N)6 random hexamers (Amersham Biosciences). The Affinity Script kit (GE Healthcare) was used to produce cDNA, and hybridized (Agilent Hi-RPM Gene Expression Hybridization Kit) to the microarray slide according to the manufacturerM-bM-^@M-^Ys instructions. Microarrays were scanned at 5 M-BM-5m using an Axon 4000A scanner, and images were acquired using GenePix Pro 3.0 software (Axon). Related analysis reference: Holmes K., Mulholland F., Pearson B. M., Pin C., McNicholl-Kennedy J., Ketley J. M., Wells J. M. (2005) Campylobacter jejuni gene expression in response to iron limitation and the role of Fur Microbiology-SGM 151 243-257 (PMID 15632442).

Project description:In order to study the function of the Campylobacter jejuni Cj1501 gene, a series of experiments were carried out. Three strains were constructed: a Cj1501 knockout strain, a strain where the Cj1501 knockout was complemented in trans, and a strain with a second copy over-expressing Cj1501 from an fdxA promoter. The transcriptomes of these were all compared to the wild-type strain. The arrays are all from RNA isolated in mid-exponential growth from independent biological replicates. Batch cultures of Campylobacter jejuni NCTC 11168 were grown in 50 ml volumes of Brucella broth in 70cm tissue culture flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (5% Oxygen, 10% Carbon dioxide, 85% Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 37 M-BM-:C. RNA was extracted from C. jejuni cultures grown to an OD600 of approximately 0.4. Briefly, 0.1 volume of 5% phenol in ethanol was mixed with the broth culture, and after centrifugation RNA was isolated with Tri Reagent (Sigma) and chloroform. RNA was further purified using the RNeasy kit (Qiagen) according to the manufacturerM-bM-^@M-^Ys instructions. The RNA was treated with Turbo DNA-free (Ambion) to remove any residual DNA according to the manufacturerM-bM-^@M-^Ys instructions. RNA concentration was determined using the Nanodrop Spectrophotometer NS-1000 (Thermo Scientific). Two or three independent RNA preparations (biological replicates) of each sample type were labelled and hybridized to custom-designed Agilent microarrays. Equal quantities of RNA from test and control cultures were labelled by using nucleotide homologues of dUTP containing either Cy3 or Cy5 fluorescent dye (Perkin Elmer). For each microarray slide, the test strain was labelled with Cy3-dUTP, while the wild-type sample was labelled with Cy5-dUTP. RNA (15 M-BM-5g) was primed with 5 M-BM-5g pd(N)6 random hexamers (Amersham Biosciences). The Affinity Script kit (GE Healthcare) was used to produce cDNA, and hybridized (Agilent Hi-RPM Gene Expression Hybridization Kit) to the microarray slide according to the manufacturerM-bM-^@M-^Ys instructions. Microarrays were scanned at 5 M-BM-5m using an Axon 4000A scanner, and images were acquired using GenePix Pro 3.0 software (Axon). Related analysis reference: Holmes K., Mulholland F., Pearson B. M., Pin C., McNicholl-Kennedy J., Ketley J. M., Wells J. M. (2005) Campylobacter jejuni gene expression in response to iron limitation and the role of Fur Microbiology-SGM 151 243-257 (PMID 15632442).

Project description:Background: During gut colonization, the enteric pathogen C. jejuni has to surmount the toxic effects of reactive oxygen species produced by its own metabolism, by the host immune system and by the intestinal microflora. Elucidation of C. jejuni oxidative stress defense mechanisms is critical for understanding Campylobacter pathophysiology. Results: The mechanisms of oxidative stress defenses in Campylobacter jejuni were characterized by transcriptional profiling, genes mutagenesis, and phenotypic analysis. The transcriptome changes, in response to H2O2, cumene hydroperoxide, or menadione exposure, were found to be oxidant specific and revealed the differential expression of genes belonging to a variety of biological pathways, from the classical oxidative stress defense systems, to the heat shock response, DNA repair and metabolism, fatty acid and capsule biosynthesis, and multidrug efflux pumps. To define the peroxide sensing regulator PerR, an isogenic mutant was constructed and its transcriptome profile compared to the wild-type strain. Sixty-six genes were found to belong to the PerR regulon. PerR appear to regulate gene expression both dependently and independently of the presence of iron and/or H2O2. The perR mutant was affected in its motility and attenuated in the chick colonization model. Mutagenic and phenotypic studies of the superoxide disumutase SodB, the alkyl-hydroxyperoxidase AhpC, and the catalase KatA, revealed their role in oxidative stress defenses and chick gut colonization. Conclusion: This study reveals the interplay between PerR, the iron metabolism and the oxidative stress defenses and highlights their role in the colonization and/or survival of C. jejuni in the chick cecum. Keywords: Transcriptional response to 3 oxidants (H2O2, menadione and cumene hydroperoxide) and characterization of the perR regulon (comparison of the transciptomes from the wild-type and perR mutant). To investigate the transcriptional responses of C. jejuni to oxidant exposure, hydrogen peroxide (H2O2), cumene hydroperoxide (CHP), or menadione sodium bisulfite (MND) was added to the 50 ml broth at a final concentration of 1 mM. The same amount of water or DMSO was added to the bacterial culture that served as reference samples for the transcriptional profile study in response to H2O2, MND or CHP. Furthermore, to investigate the transcriptional response of C. jejuni to H2O2 exposure in the presence of excess iron, ferrous sulfate was added to the bacterial culture at a final concentration of 40 µM, 15 min prior to H2O2 exposure. Ten minutes after the addition of the oxidant, total RNA was extracted and processed for microarray hybridization. To identify the PerR regulon, the wild-type strain C. jejuni NCTC 11168 and the perR mutant were grown in 500 ml flasks containing 250 ml of MEMα medium. At mid-log phase, 50 ml of the cultures were transferred to 100 ml flasks and ferrous sulfate and/or H2O2 were added . Ten minutes following the addition of H2O2 the cells were collected and the total RNA extracted.

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AI-2 does not function as a quorum sensing molecule in Campylobacter jejuni during exponential growth in vitro

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