Exposure of microaerobic Campylobacter jejuni to 10 micromolar NOC-5 & NOC-7
Ontology highlight
ABSTRACT: Two batch cultures of Wild-type C. jejuni NCTC 11168 were grown in 100 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % Oxygen, 10 % Carbon dioxide, 80 % Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 ºC. When mid-exponential phase was reached 0.010 mM NOC-5 & NOC-7 was added to one of the cultures. After a 15 minute exposure samples of both treated and untreated cells were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using Qiagen’s RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis.
Project description:Batch cultures of Wild-type C. jejuni NCTC 11168 were grown in 200 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % Oxygen, 10 % Carbon dioxide, 80 % Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 ºC. When mid-exponential phase was reached 0.010 mM NOC-5 & NOC-7 was added to one of the cultures. After a 15 minute exposure samples of both treated and untreated cells were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using Qiagen’s RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis.
Project description:Two batch cultures of Wild-type C. jejuni NCTC 11168 were grown in 100 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % Oxygen, 10 % Carbon dioxide, 80 % Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 M-BM-:C. When mid-exponential phase was reached 0.010 mM NOC-5 & NOC-7 was added to one of the cultures. After a 15 minute exposure samples of both treated and untreated cells were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using QiagenM-bM-^@M-^Ys RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Batch cultures of Wild-type C. jejuni NCTC 11168 were grown in 100 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % Oxygen, 10 % Carbon dioxide, 80 % Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 M-BM-:C. When mid-exponential phase was reached 0.25 mM GSNO was added to half of the cultures. After a 10 minute exposure, 30 ml samples of both treated and untreated cells were mixed immediately on ice with 3.56 ml 100% ethanol and 185 M-BM-5l phenol to stabilize the RNA. The cells were subsequently harvested by centrifugation. Total RNA was purified by using a Qiagen RNeasy Mini kit as recommended by the supplier. Equivalent amounts of RNA (15 M-NM-<g) from control and test cultures were used as template for synthesis of labelled cDNA. Labelling was done by using dCTP nucleotide analogues containing either Cy3 or Cy5 fluorescent dyes. RNA was primed with 9 M-NM-<g pd(N)6 random hexamers (Amersham Biosciences). For annealing, the mixture was incubated for 10 min at 65oC and then 10 min at room temperature. Each reaction mixture (0.5 mM dATP, dTTP and dGTP, 0.2 mM dCTP, 0.1 mM DTT (Invitrogen) and 1 mM Cy3-dCTP or Cy5-dCTP, total volume 25ul) was incubated for 3 h at 42 oC with 200 U of Superscript III RNase-H Reverse Transcriptase (Invitrogen). The reaction was terminated by the addition of 5u1 mM NaOH and heating the tube to 65 oC for 10 min to hydrolyse the RNA. Then it was neutralised with 5ul 1M HCl and 1 M TE (pH 8). Purification of cDNA was done with a PCR purification kit (Qiagen). The cDNA was eluted and resuspended in 30 M-NM-<l elution buffer (Qiagen, supplied in kit). Each slide set (control slide and dye-swap) was prepared as follows: For control slide Cy3-dCTP labelled control cDNA was mixed with Cy5-dCTP labelled test cDNA. For dye-swap slide Cy5-dCTP labelled control cDNA was mixed with Cy3-dCTP labelled test cDNA. This is made for compensate possible differences in the labelled nucleotides incorporation. The slides used were C. jejuni OciChipM-BM-. arrays from Ocimum Biosolutions. The cDNA mixture for each slide was dried by evaporation for approximately 35 min in a SPD 121P SpeedVacM-BM-. (Thermo Savant, Waltham, MA, USA) The dry cDNA was resuspended in pre-warmed (42M-BM-:C) salt-based hybridisation buffer (Ocimum Biosolutions) and was heated to 95 M-BM-0C for 3 min and then placed on ice for 3 min. The spoted area of the slide (located with an array finder) was enclosed within a gene frame (MWG/Ocimum). The cDNA suspension was distributed through the inner space of the gene frame and enclosed with an air-tight coverslip. The slides were incubated for 16-24 hours at 42M-BM-: C in sealed MWG hybridisation chambers shaken in a water bath. After incubation, gene frames and coverslips were removed and slides washed sequentially in 2x, 1x, 0.2x y 0.1x SSC buffer, by shaking for 5 minutes at 80 rpm at 37M-BM-: C pre-warmed buffer. (2x buffer was supplemented with 1% SDS). Then the slides were dried by centrifugation at 250 x g for 5 min. Slides were scanned using an Affymetrix 428 scanner. The processing of images and quantification of the microarrays signal was done using software from Biodiscovery Inc (Imagene, version 4.0 and Genesight, version 4.0). Spots with signal intensity lower than background or other significant blemishes were eliminated from subsequent processing. Mean values from each channel were then log2 transformed and normalised using the Subtract by Mean method to remove intensity-dependent effects in the log2 (ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalised values. Significance analysis of the data used the StudentM-bM-^@M-^Ys t test to determine the probability that the average of the experimental replicates was significantly different from the average of the control replicates. p-values for the data were calculated by treating each slide as a repeat using Genesight 4. Genes differentially regulated M-bM-^IM-% 2-fold and displaying a p-value of M-bM-^IM-$ 0.05 were defined as being statistically significant and differentially transcribed.
Project description:Batch cultures of Wild-type C. jejuni NCTC 11168 were grown in 200 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % Oxygen, 10 % Carbon dioxide, 80 % Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 M-BM-:C. When mid-exponential phase was reached 0.010 mM NOC-5 & NOC-7 was added to one of the cultures. After a 15 minute exposure samples of both treated and untreated cells were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using QiagenM-bM-^@M-^Ys RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Batch cultures of Wild-type C. jejuni NCTC 11168 were grown in 200 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % Oxygen, 10 % Carbon dioxide, 80 % Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 M-BM-:C. When mid-exponential phase was reached 0.25 mM GSNO was added to half of the cultures. After a 10 minute exposure, 30 ml samples of both treated and untreated cells were mixed immediately on ice with 3.56 ml 100% ethanol and 185 M-BM-5l phenol to stabilize the RNA. The cells were subsequently harvested by centrifugation. Total RNA was purified by using a Qiagen RNeasy Mini kit as recommended by the supplier. Equivalent amounts of RNA (15 M-NM-<g) from control and test cultures were used as template for synthesis of labelled cDNA. Labelling was done by using dCTP nucleotide analogues containing either Cy3 or Cy5 fluorescent dyes. RNA was primed with 9 M-NM-<g pd(N)6 random hexamers (Amersham Biosciences). For annealing, the mixture was incubated for 10 min at 65oC and then 10 min at room temperature. Each reaction mixture (0.5 mM dATP, dTTP and dGTP, 0.2 mM dCTP, 0.1 mM DTT (Invitrogen) and 1 mM Cy3-dCTP or Cy5-dCTP, total volume 25ul) was incubated for 3 h at 42 oC with 200 U of Superscript III RNase-H Reverse Transcriptase (Invitrogen). The reaction was terminated by the addition of 5ul 1 mM NaOH and heating the tube to 65 oC for 10 min to hydrolyse the RNA. Then it was neutralised with 5ul 1 M HCl and 1 M TE (pH 8). Purification of cDNA was done with a PCR purification kit (Qiagen). The cDNA was eluted and resuspended in 30 M-NM-<l elution buffer (Qiagen, supplied in kit). Each slide set (control slide and dye-swap) was prepared as follows: For control slide Cy3-dCTP labelled control cDNA was mixed with Cy5-dCTP labelled test cDNA. For dye-swap slide Cy5-dCTP labelled control cDNA was mixed with Cy3-dCTP labelled test cDNA. This is made for compensate possible differences in the labelled nucleotides incorporation. The slides used were C. jejuni OciChipM-BM-. arrays from Ocimum Biosolutions. The cDNA mixture for each slide was dried by evaporation for approximately 35 min in a SPD 121P SpeedVacM-BM-. (Thermo Savant, Waltham, MA, USA) The dry cDNA was resuspended in pre-warmed (42M-BM-:C) salt-based hybridisation buffer (Ocimum Biosolutions) and was heated to 95 M-BM-0C for 3 min and then placed on ice for 3 min. The spoted area of the slide (located with an array finder) was enclosed within a gene frame (MWG/Ocimum). The cDNA suspension was distributed through the inner space of the gene frame and enclosed with an air-tight coverslip. The slides were incubated for 16-24 hours at 42M-BM-: C in sealed MWG hybridisation chambers shaken in a water bath. After incubation, gene frames and coverslips were removed and slides washed sequentially in 2x, 1x, 0.2x y 0.1x SSC buffer, by shaking for 5 minutes at 80 rpm at 37M-BM-: C pre-warmed buffer. (2x buffer was supplemented with 1% SDS). Then the slides were dried by centrifugation at 250 x g for 5 min. Slides were scanned using an Affymetrix 428 scanner. The processing of images and quantification of the microarrays signal was done using software from Biodiscovery Inc (Imagene, version 4.0 and Genesight, version 4.0). Spots with signal intensity lower than background or other significant blemishes were eliminated from subsequent processing. Mean values from each channel were then log2 transformed and normalised using the Subtract by Mean method to remove intensity-dependent effects in the log2 (ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalised values. Significance analysis of the data used the StudentM-bM-^@M-^Ys t test to determine the probability that the average of the experimental replicates was significantly different from the average of the control replicates. p-values for the data were calculated by treating each slide as a repeat using Genesight 4. Genes differentially regulated M-bM-^IM-% 2-fold and displaying a p-value of M-bM-^IM-$ 0.05 were defined as being statistically significant and differentially transcribed.
Project description:Batch cultures of Wild-type C. jejuni NCTC11168 were grown in 150 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % O2, 10 % CO2, 80 % N2) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 ºC. When mid-exponential phase was reached 0.25 mM GSNO was added to half of the cultures. After a 10 minute exposure samples of both treated and untreated cells were harvested into phenol/ethenol to stabilize the RNA and total RNA was purified using Qiagen’s RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Keywords: Stress-response of batch cultures to GSNO
Project description:Batch cultures of Wild-type C. jejuni NCTC 11168 were grown in 150 ml volumes of Mueller-Hinton broth in 250 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10 % Oxygen, 10 % Carbon dioxide, 80 % Nitrogen) from Don Whitley Scientific, Ltd which also maintained the growth temperature at 42 ºC. When mid-exponential phase was reached 0.25 mM GSNO was added to half of the cultures. After a 5/10/15/45 minute exposure samples of both treated and untreated cells were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using Qiagen’s RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Keywords: Time Course
Project description:Two batch cultures of wild-type C. jejuni NCTC 11168 were grown in 200 ml volumes of Mueller-Hinton broth in 500 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10% Oxygen, 10% Carbon dioxide, 80% Nitrogen) from Don Whitley Scientific, Ltd, which also maintained the growth temperature at 42 M-BM-:C. When mid-exponential phase was reached, a custom-made diffusion capsule (as described in Pirt, 1971) containing chicken caecal contents was placed for 10, 30, or 60 minutes. After the exposure, samples of both treated and untreated cells were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using Qiagen's RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Batch cultures of wild-type C. jejuni NCTC 11168 were grown in 200 ml volumes of Mueller-Hinton broth in 500 ml baffled flasks. Microaerophilic conditions were generated using a MACS-VA500 microaerophilic work station (10% Oxygen, 10% Carbon dioxide, 80% Nitrogen) from Don Whitley Scientific, Ltd, which also maintained the growth temperature at 42 M-BM-:C. When mid-exponential phase was reached, a custom-made diffusion capsule (as described in Pirt, 1971) containing chicken caecal contents was placed for 10, 30, or 60 minutes. After the exposure, 30 ml samples of both treated and untreated cells were mixed immediately on ice with 3.56 ml 100% ethanol and 185 M-BM-5l phenol to stabilize the RNA. The cells were subsequently harvested by centrifugation. Total RNA was purified by using a Qiagen RNeasy Mini kit as recommended by the supplier. Equivalent amounts of RNA (15 M-NM-<g) from control and test cultures were used as template for synthesis of labelled cDNA. Labelling was done by using dCTP nucleotide analogues containing either Cy3 or Cy5 fluorescent dyes. RNA was primed with 9 M-NM-<g pd(N)6 random hexamers (Amersham Biosciences). For annealing, the mixture was incubated for 10 min at 65oC and then 10 min at room temperature. Each reaction mixture (0.5 mM dATP, dTTP and dGTP, 0.2 mM dCTP, 0.1 mM DTT (Invitrogen) and 1 mM Cy3-dCTP or Cy5-dCTP, total volume 25ul) was incubated for 3 h at 42 oC with 200 U of Superscript III RNase-H Reverse Transcriptase (Invitrogen). The reaction was terminated by the addition of 5ul 1 mM NaOH and heating the tube to 65 oC for 10 min to hydrolyse the RNA. Then it was neutralised with 5ul 1 M HCl and 1 M TE (pH 8). Purification of cDNA was done with a PCR purification kit (Qiagen). The cDNA was eluted and resuspended in 30 M-NM-<l elution buffer (Qiagen, supplied in kit). Each slide set (control slide and dye-swap) was prepared as follows: For the control slide, Cy3-dCTP labelled control cDNA was mixed with Cy5-dCTP labelled test cDNA. For the dye-swap slide, Cy5-dCTP labelled control cDNA was mixed with Cy3-dCTP labelled test cDNA. This is made to compensate for possible differences in the labelled nucleotides incorporation. The slides used were C. jejuni OciChipM-BM-. arrays from Ocimum Biosolutions. The cDNA mixture for each slide was dried by evaporation for approximately 35 min in a SPD 121P SpeedVacM-BM-. (Thermo Savant, Waltham, MA, USA). The dry cDNA was resuspended in pre-warmed (42M-BM-:C) salt-based hybridisation buffer (Ocimum Biosolutions) and was heated to 95 M-BM-0C for 3 min and then placed on ice for 3 min. The spotted area of the slide (located with an array finder) was enclosed within a gene frame (MWG/Ocimum). The cDNA suspension was distributed through the inner space of the gene frame and enclosed with an air-tight coverslip. The slides were incubated for 16-24 hours at 42M-BM-: C in sealed MWG hybridisation chambers shaken in a water bath. After incubation, gene frames and coverslips were removed and slides washed sequentially in 2x, 1x, 0.2x y 0.1x SSC buffer, by shaking for 5 minutes at 80 rpm at 37M-BM-: C pre-warmed buffer. (2x buffer was supplemented with 1% SDS). Then the slides were dried by centrifugation at 250 x g for 5 min. Slides were scanned using an Affymetrix 428 scanner. The processing of images and quantification of the microarrays signal was done using software from Biodiscovery Inc. (ImaGene, version 4.0 and GeneSight, version 4.0). Spots with signal intensity lower than background or other significant blemishes were eliminated from subsequent processing. Mean values from each channel were then log2 transformed and normalised using the Subtract by Mean method to remove intensity-dependent effects in the log2 (ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalised values. Significance analysis of the data used the Student's t test to determine the probability that the average of the experimental replicates was significantly different from the average of the control replicates. p-values for the data were calculated by treating each slide as a repeat using Genesight 4. Genes differentially regulated M-bM-^IM-% 2-fold and displaying a p-value of M-bM-^IM-$ 0.05 were defined as being statistically significant and differentially transcribed.
Project description:Coordination of chromosome segregation and cytokinesis is crucial for efficient cell proliferation. In Bacillus subtilis the nucleoid occlusion protein Noc protects chromosomes by associating with the chromosome and preventing cell division in its vicinity. Using protein localization, ChAP-on-Chip and bioinformatics, we have identified a consensus Noc-binding DNA sequence (NBS), and show that Noc is targeted to about 70 discrete regions scattered around the chromosome, though absent from a large region around the replication terminus. Purified Noc bound specifically to an NBS in vitro. NBSs inserted near the replication terminus bound Noc-YFP and caused a delay in cell division. An autonomous plasmid carrying an NBS recruited Noc-YFP and conferred a severe Noc-dependent inhibition of cell division. This shows that Noc is a potent inhibitor of division but that its activity is strictly localized by interaction with NBS sites in vivo. We propose that Noc not only serves as a spatial regulator of cell division to protect the nucleoid, but also a timing device with an important role in the co-ordination of chromosome segregation and cell division.
Project description:Successive division events in the spherically shaped bacterium Staphylococcus aureus are oriented in three alternating perpendicular planes. The mechanisms that underlie this relatively unique pattern of division and coordinate it with chromosome segregation remain largely unknown. Thus far, the only known spatial regulator of division in this organism is the nucleoid occlusion protein Noc that inhibits assembly of the cytokinetic ring over the chromosome. However, Noc is not essential in S. aureus, indicating that additional regulators are likely to exist. To search for these factors, we screened for mutants that are synthetic lethal with Noc inactivation. Our characterization of these mutants led to the discovery that S. aureus Noc also controls the initiation of DNA replication. We show that cells lacking Noc over-initiate and mutations in the initiator gene dnaA suppress this defect. Importantly, these dnaA mutations also partially suppress the division problems associated with ∆noc. Reciprocally, we show that over-expression of DnaA enhances the over-initiation and cell division phenotypes of cells lacking Noc. Thus, a single factor both blocks cell division over chromosomes and helps to ensure that new rounds of DNA replication are not initiated prematurely. This degree of economy in coordinating key cell biological processes has not been observed in rod-shaped bacteria and may reflect the challenges posed by the reduced cell volume and complicated division pattern of this spherical pathogen.
Project description:Successive division events in the spherically shaped bacterium Staphylococcus aureus are oriented in three alternating perpendicular planes. The mechanisms that underlie this relatively unique pattern of division and coordinate it with chromosome segregation remain largely unknown. Thus far, the only known spatial regulator of division in this organism is the nucleoid occlusion protein Noc that inhibits assembly of the cytokinetic ring over the chromosome. However, Noc is not essential in S. aureus, indicating that additional regulators are likely to exist. To search for these factors, we screened for mutants that are synthetic lethal with Noc inactivation. Our characterization of these mutants led to the discovery that S. aureus Noc also controls the initiation of DNA replication. We show that cells lacking Noc over-initiate and mutations in the initiator gene dnaA suppress this defect. Importantly, these dnaA mutations also partially suppress the division problems associated with ∆noc. Reciprocally, we show that over-expression of DnaA enhances the over-initiation and cell division phenotypes of cells lacking Noc. Thus, a single factor both blocks cell division over chromosomes and helps to ensure that new rounds of DNA replication are not initiated prematurely. This degree of economy in coordinating key cell biological processes has not been observed in rod-shaped bacteria and may reflect the challenges posed by the reduced cell volume and complicated division pattern of this spherical pathogen.
Project description:Successive division events in the spherically shaped bacterium Staphylococcus aureus are oriented in three alternating perpendicular planes. The mechanisms that underlie this relatively unique pattern of division and coordinate it with chromosome segregation remain largely unknown. Thus far, the only known spatial regulator of division in this organism is the nucleoid occlusion protein Noc that inhibits assembly of the cytokinetic ring over the chromosome. However, Noc is not essential in S. aureus, indicating that additional regulators are likely to exist. To search for these factors, we screened for mutants that are synthetic lethal with Noc inactivation. Our characterization of these mutants led to the discovery that S. aureus Noc also controls the initiation of DNA replication. We show that cells lacking Noc over-initiate and mutations in the initiator gene dnaA suppress this defect. Importantly, these dnaA mutations also partially suppress the division problems associated with ∆noc. Reciprocally, we show that over-expression of DnaA enhances the over-initiation and cell division phenotypes of cells lacking Noc. Thus, a single factor both blocks cell division over chromosomes and helps to ensure that new rounds of DNA replication are not initiated prematurely. This degree of economy in coordinating key cell biological processes has not been observed in rod-shaped bacteria and may reflect the challenges posed by the reduced cell volume and complicated division pattern of this spherical pathogen.