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Synechocystis sp. PCC 6803 response to inorganic carbon limitation

ABSTRACT: Synechocystis 6803 cells was grown photoautotrophically at 32 °C buffered in BG-11 and bubbled with 3% CO2. A relatively mild Ci stress was applied by switching the aeration from 3% CO2 to air alone. After incubation under designated conditions, a 100-ml aliquot of culture was immediately combined with an equal volume of ice-cold mixture of phenol and ethanol (1:10, w/v) in an ice bath. The resultant cells were collected by centrifugation at 1000 x g for 10 min at 4 °C. Total RNA was isolated with RNeasy Midi Kit (Qiagen, Valencia, CA) and further treated with the DNA-free kit (Ambion, Austin, TX). Fluorescently labeled cDNA was produced via a two-step indirect procedure involving cDNA synthesis from 16 µg of total RNA in a reverse transcriptase reaction incorporating aminoallyl-modified deoxynucleotide, followed by the second step involving chemical coupling of fluorescent dye to the introduced amino moieties of the synthesized cDNA. Labeled cDNA were adjusted to 14.75 µl, and the remainder of the hybridization components containing 2.5 µl of 10 µg µl-1 salmon sperm DNA, 8.75 µl of 20x SSC, 0.25 µl of 10% SDS, and 8.75 µl of formamide were added. The mixture was then heated for 2 min at 99 °C and maintained at 42 °C until hybridization. Hybridizations were preformed in a static incubator at 42 °C for 12-16 h then washed by placing in a 250-ml solution of 2x SSC and 0.1% SDS at 42 °C for 5 min with gentle agitation provided by rotation of a magnetic stir bar. The slide was transferred quickly to a 250-ml solution of 0.1x SSC and 0.1% SDS, incubated for 10 min at room temperature with gentle agitation, and washed five additional times in 0.1x SSC for 1 min at room temperature. Hybridization signals from the microarray were quantified using GenePix Pro 4.1 (Axon Instruments, Union City, CA). The quality control procedures were conducted in the image analysis software, and then data were saved to Acuity 3.1 (Axon Instruments). Keywords: time-course

ORGANISM(S): Synechocystis sp. PCC 6803

PROVIDER: GSE1695 | GEO | 2004/08/24

SECONDARY ACCESSION(S): PRJNA90659

REPOSITORIES: GEO

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Project description:MicroPoly(A)Pure kits (Ambion) were used to prepare mRNA from P. salmonis-infected and control Atlantic salmon head kidney. Head kidney mRNA samples were prepared from pooled (n = 10) infected or control kidney. Approximately 200 ng of infected or control head kidney mRNA was used as template in aRNA synthesis reactions. Two infected head kidney samples were pooled to yield 8.9 ug of aRNA, and a single control head kidney sample contained 8.4 ug of aRNA. Infected and control head kidney aRNA samples were visualized on agarose gels to check quality and quantity (data not shown). Except for the amounts of aRNA and reverse transcription (RT) primer used, head kidney target labeling reactions and microarray hybridizations were identical. Head kidney target syntheses used 2 ug of aRNA and 2 ug of random primers (Roche). RT primers were mixed with aRNA samples, and nuclease-free H2O (Invitrogen) was added to make 10 ul total volume. Samples were incubated at 70 degrees C for 4 min, then placed on ice. RT reactions included 50 mM Tris HCl pH 8.3, 75 mM KCl, 3 mM MgCl2, 10 mM DTT, 0.5 mM each dATP, dCTP, and dGTP, 0.2 mM dTTP, 0.05 mM Cy3-dUTP or Cy5-dUTP (Amersham), 40U RNAguard ribonuclease inhibitor (Amersham), and 400U Superscript II Rnase H- reverse transcriptase (Invitrogen). RT reactions were incubated at 42 degrees C for 2.5 h, followed by addition of 0.025U RNase A (Sigma) and 1.5U RNase H (New England BioLabs) and incubation at 37 degrees C for 30 min. Labeled targets were cleaned using the Qiaquick PCR purification kit (Qiagen) and precipitated, with 300 mM sodium acetate, 1 ul of 20 ug/ul glycogen (Invitrogen), and 2.5 volumes of 100% ethanol, at -20 degrees C overnight. Each labeled target was recovered by centrifugation (14,000 rpm, 4 degrees C, 1 h), washed in 70% ethanol, air-dried, and resuspended in 60 ul of hybridization buffer: 50% deionized formamide, 5X SSC, 0.1% SDS, 5 ul of 5 ug/ul oligo dT (5’T18[Q-N]3’), 5 ul of 2 ug/ul BSA (Pierce), and 2 ul of 10 ug/ul sonicated human placental DNA (Sigma). Targets were incubated at 96 degrees C for 3 min, and then at 65 degrees C until applied to microarrays. Microarrays were prepared for hybridization by washing 2 X 5 min in 0.1% SDS, washing 5 X 1 min in MilliQ H2O, immersing 3 min in 95 degrees C MilliQ H2O, and drying by centrifugation (2000 rpm, 5 min, in 50 ml conical tube). Microarray hybridizations were run in the dark under HybriSlips hybridization covers (Grace Biolabs) in slide hybridization chambers (Corning) submerged in a 45 degrees C water bath for 16 h. Coverslips were floated off in 45 degrees C (1X SSC, 0.2% SDS), and arrays were washed 1 X 10 min in 45 degrees C (1X SSC, 0.2% SDS), 3 X 4 min in room temperature (0.1X SSC, 0.1% SDS), and 4 X 4 min in room temperature 0.1X SSC. Slides were dried by centrifugation as before. Fluorescent images of hybridized arrays were acquired immediately at 10 um resolution using ScanArray Express (PerkinElmer). The Cy3 and Cy5 cyanine fluors were excited at 543 nm and 633 nm respectively, and the same laser power (90%) and photomultiplier tube (PMT) settings were used for all slides in a study (PMT 75 Cy3, PMT 63 or 64 Cy5 for head kidney study). Fluorescent intensity data were extracted from TIF images using Imagene 5.5 software (Biodiscovery). Keywords: other

Project description:MicroPoly(A)Pure kits (Ambion) were used to prepare mRNA from P. salmonis-infected and control Atlantic salmon macrophages. Infected and control (24 h incubation) macrophage mRNA samples were subjected to two rounds of amplification using the MessageAmp aRNA kit (Ambion) and manufacturer's instructions. Approximately 400 ng of macrophage mRNA was used as template in the first round of amplification, yielding 8.1 ug of infected macrophage aRNA and 7.8 ug of control macrophage aRNA. Approximately 1 ug of first-round macrophage aRNA was used as template in the second round of amplification, yielding 81.2 ug of infected macrophage aRNA and 83.3 ug of control macrophage aRNA. Infected and control macrophage aRNA samples were visualized on agarose gels to check quality and quantity. Except for the amounts of aRNA and reverse transcription (RT) primer used, macrophage target labeling reactions and microarray hybridizations were identical. Macrophage target syntheses used 5 ug of second-round aRNA and 5 ug of random primers (Roche). RT primers were mixed with aRNA samples, and nuclease-free H2O (Invitrogen) was added to make 10 ul total volume. Samples were incubated at 70 degrees C 4 min, then placed on ice. RT reactions included 50 mM Tris HCl pH 8.3, 75 mM KCl, 3 mM MgCl2, 10 mM DTT, 0.5 mM each dATP, dCTP, and dGTP, 0.2 mM dTTP, 0.05 mM Cy3-dUTP or Cy5-dUTP (Amersham), 40U RNAguard ribonuclease inhibitor (Amersham), and 400U Superscript II Rnase H- reverse transcriptase (Invitrogen). RT reactions were incubated at 42 degrees C for 2.5 h, followed by addition of 0.025U RNase A (Sigma) and 1.5U RNase H (New England BioLabs) and incubation at 37 degrees C for 30 min. Labeled targets were cleaned using the Qiaquick PCR purification kit (Qiagen) and precipitated, with 300 mM sodium acetate, 1 ul of 20 ug/ul glycogen (Invitrogen), and 2.5 volumes of 100% ethanol, at -20 degrees C overnight. Each labeled target was recovered by centrifugation (14,000 rpm, 4 degrees C, 1 h), washed in 70% ethanol, air-dried, and resuspended in 60 ul of hybridization buffer: 50% deionized formamide, 5X SSC, 0.1% SDS, 5 ul of 5 ug/ul oligo dT (5'T18[Q-N]3'), 5 ul of 2 ug/ul BSA (Pierce), and 2 ul of 10 ug/ul sonicated human placental DNA (Sigma). Targets were incubated at 96 degrees C for 3 min, and then at 65 degrees C until applied to microarrays. Microarrays were prepared for hybridization by washing 2 X 5 min in 0.1% SDS, washing 5 X 1 min in MilliQ H2O, immersing 3 min in 95 degrees C MilliQ H2O, and drying by centrifugation (2000 rpm, 5 min, in 50 ml conical tube). Microarray hybridizations were run in the dark under HybriSlips hybridization covers (Grace Biolabs) in slide hybridization chambers (Corning) submerged in a 45 degrees C water bath for 16 h. Coverslips were floated off in 45 degrees C (1X SSC, 0.2% SDS), and arrays were washed 1 X 10 min in 45 degrees C (1X SSC, 0.2% SDS), 3 X 4 min in room temperature (0.1X SSC, 0.1% SDS), and 4 X 4 min in room temperature 0.1X SSC. Slides were dried by centrifugation as before. Fluorescent images of hybridized arrays were acquired immediately at 10 um resolution using ScanArray Express (PerkinElmer). The Cy3 and Cy5 cyanine fluors were excited at 543 nm and 633 nm respectively, and the same laser power (90%) and photomultiplier tube (PMT) settings were used for all slides in a study (PMT 72 Cy3, PMT 63 or 64 Cy5 for macrophage study). Fluorescent intensity data were extracted from TIF images using Imagene 5.5 software (Biodiscovery). Keywords: other

Project description:The objective of the present study was to use our own fabricated bovine liver cDNA microarray to profile genome-wide expression patterns of genes in the liver of cow throughout pregnancy. Ten-microgram of pooled liver total RNA obtained from nonpregnant cycling cows was reverse transcribed in the presence of cyanine-3-fluorescent dye (Cy3)-conjugated dUTP (Amersham Pharmacia Biotech) by using Superscript II reverse transcriptase (Life Technologies, Rockville, MD) to yield Cy3 fluorescence-labeled control cDNA probe. Similarly, liver total RNA obtained from cows on days 19, 27, 49, 58, 150 and 245 of pregnancy was separately reverse transcribed in the presence of Cy5-conjugated dUTP by using Superscript II reverse transcriptase to yield Cy5 fluorescence-labeled test cDNA probe. After a 2-h reverse transcription reaction at 42oC, RNA was degraded by addition of 1.5 µl of an alkaline solution (1N NaOH / 20 mM EDTA), and neutralized by addition of 1.5 µl 1N HCl. 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Compared with the linear regression, the accuracy is improved, if the points in scatter plot of Cy3 vs. Cy5 were not distributed around the straight line. The local variance normalization controls the noise (background) in the raw data to a greater extent where the normalized data, in many cases, did not show significant fold-differences in comparison with background-subtracted raw intensity ratios, which frequently displayed higher fold-differences. Thus, the variance method that we employed to bovine liver array data has produced much reliable normalized ratios. To group liver genes with similar expression patterns throughout bovine pregnancy, two clustering algorithm were employed. The hierarchical clustering algorithm was performed using the software, Cluster 3.0, created and made freely available by Dr. Michiel de Hoon (http://bonsai.ims.u-tokyo.ac.jp/~mdehoon/software/cluster/software.htm) based on the original version written by Dr. Michael Eisen (http://rana.lbl.gov/), and the software TreeView (http://rana.lbl.gov/). For hierarchical clustering, genes with either 2 or more than 2-fold induction or 2 or more than 2-fold repression at least at one point of the sampling period were selected. All ratio values were log transformed (base 2) to treat inductions or repressions of identical magnitude as numerically equal but with opposite sign, and subjected to centroid linkage clustering. Self-Organizing Maps (SOMs) algorithm was performed using the software GeneCluster 2 made freely available by Whitehead Institute Center for Genome Research (http://www-genome.wi.mit.edu/cancer/software/genecluster2/gc2.html). The SOMs were performed on the present data to better visualization of clusters of genes with their expression patterns plotted on an x-y axis. For SOMs, genes with either 1.5-fold (and above) induction or 1.5-fold (and above) repression at least at one point of the sampling period were selected. The minimum fold difference i.e., 1.5-fold, chosen for the analyses in the present study was based on the calculation that the technical variation contributing to the expression level of each individual gene due either to different labeling efficiencies of cyanine dyes or labeling procedure or both, was found to be within the range of 1.41-fold induction or repression. Therefore, either the induction or the repression of a particular gene by 1.5-fold or above was considered significant. Keywords = differential liver gene expression Keywords = bovine pregnancy Keywords = hierarchical clustering Keywords = self-organizing maps Keywords: time-course

Project description:We have performed the hybridisation in triplicate using total RNA samples pooled from three independent batches of primary cortical neuron culture derived from E14.5 CD1 mouse brains on one day in vitro (1DIV). We stimulated the cells with 50 ng/ml FGF2 in the presence of 10 μg/ml heparin for 4 hours, and the expression of genes were compared to those in the absence of FGF2. The data were obtained from the three experiments with the best possible conditions and strict measures were applied for the purpose of quality control. Seventeen features representing housekeeping genes in the array (GAPDH, HPRT and S16, S9, and S8 ribosomal proteins) gave average value of Ratio of Medians (ROM), 1.20 ± 0.28, which was confirmed to be acceptable. Total RNA was extracted from cells in the growing phase by using RNA Clean (Hybaid) according to the manufacturer’s instruction and further purified with RNeasy mini kit (Qiagen). Direct labelling of 20 µg of total RNA primed with Oligo(dT) was performed in the presence of Cy-5 and Cy-3-dUTP (Amersham Pharmacia Biotech) using SuperScript II (Invitrogen). The Cy5- and Cy3-labelled cDNA samples were then mixed and purified with GFX DNA purification kit (Amersham Pharmacia Biotech). The samples were added with 1.2 µg of salmon sperm DNA and 5 µg of Poly(dA) and dried in SpeedVac at 60°C. The high-density glass microarray chips were prepared at the EMBL core facility by spotting the PCR products prepared from the NIA 15k cDNA mouse clone set. Array slides were pre-hybridized in 6x SSC, 0.5% SDS, 1% BSA at 42°C for 1 hour and incubated in a boiled water for 2 min shortly prior to hybridisation. The cDNA samples were resuspended in 15 µl of hybridisation buffer (50% formamide, 6x SSC, 0.5% SDS and 5% Denhardt’s) and denatured by incubating at 95°C for 2 min. Hybridisation was at 42oC for 16 hours. The slides were washed for 10 min each with 2 x SSC, then with 0.5 x SSC, 0.1%SDS, followed by 0.1 x SSC, 0.1%SDS, at room temperature. Scanning was performed with GenePix 4000B (Axon). Quality control was performed, firstly by eye, to confirm scanner alignment and absence of significant bubbles and scratches. Scatter plots were further used to eliminate the unacceptable hybridisation data. The multiple spike-in controls RNA template were added to the sample upon direct labelling, and the successful labelling and hybridisation was confirmed in each hybridisations. GenePix Pro grogram calculates the Normalisation Factor of each hybridisation, based on the premise that the arithmetic mean of the ratios from every feature on the given array should be equal to 1. Normalisation was therefore performed by multiplying the Factor to Ratio of Medians (ROM) in each gene. The program also identifies features that did not give good alignment to the expected spotted area as “flagged” spots, indicative of the impaired-quality hybridisation of the specific genes. Keywords = NIA mouse 15k Keywords = cortical neuron Keywords = FGF Keywords: other

Project description:A single-domain globin (cgb) mutant strain of Campylobacter jejuni NCTC11168 was grown in 2 homemade, parallel chemostats. Cells were grown in 125 ml volumes of Mueller-Hinton Broth where the growth rate was controlled by the dilution rate (0.1 h-1). A gas mix of 80% nitrogen, 10% carbon dioxide and 10% oxygen was pumped into the head-space of the vessels at a rate of 0.25 l/min to obtain a microaerobic environment and the culture was maintained at 42 ºC via a water jacket. Cells were grown as above until steady-state had been reached. At steady-state one of the cultures was exposed to 10 uM NOC-5 & -7 (final concentration) for a period of 10 min. Samples of both the control and stressed cultures 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. Equal quantities of RNA from control and GSNO-supplemented cultures were labelled using nucleotide analogues of dCTP containing either Cy3 or Cy5 fluorescent dyes. The average signal intensity and local background correction were obtained using a commercially available software package from Biodiscovery, Inc (Imagene, version 4.0 and GeneSight, version 4). The mean values from each channel were log2 transformed and normalised using the Lowess method to remove intensity-dependent effects in the log2(ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalized values. Keywords: Stress-response of a cgb mutant to NO A C. jejuni NCTC11168 cgb mutant was grown in two parallel custom-built chemostats based on Sigma Proculture Dynalift spinner flasks with a working volume of 125 ml, and the dilution rate (which at steady state is equal to the specific growth rate) of 0.1 h-1. A gas mix of 10% O2, 10% CO2 and 80% N2 was passed into the head space of the culture vessel at a rate of 0.25 l min-1 to obtain a microaerobic atmosphere, and silicone water jackets maintained the temperature at 42 ºC. The flasks were placed on KMO 2 basic IKA-Werke stirrers (arbitrary setting, 260; Scientific Laboratory Supplies), which gaveeffective transfer of O2 from the gaseous atmosphere to the culture by virtue of a stable vortex. A fresh overflow sample was used to check the pH at the time of harvest (which was consistently between 6.6 and 7) and to ensure that there was no contamination by plating a 20 μl sample onto both nutrient agar plates incubated at 37 °C at atmospheric oxygen, and Mueller-Hinton plates incubated at 42 °C in the microaerophilic work station. When staedy-state was reached, as verified by collecting at least 5 culture volumes, NOC-5 & -7 (final concentration 10 uM) was added to one culture. After a further 10 min the 125 ml volume was separated into 3 equal volumes and each was mixed immediately on ice with 3.56 ml 100% ethanol and 185 ml 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. cDNA synthesis was carried out using 12 µg of starting material, which was primed with 9 µg of pd(N)6 random hexamers (Amersham Biosciences). Reaction mixtures (20 µl) containing 0.5 mM ATP, 0.5 mM TTP, 0.5 mM GTP, 0.2 mM CTP, and 1 mM Cy3- or 1 mM Cy5-dCTP were incubated for 2 h at 42 °C with 200 U of Superscript II RNase H reverse transcriptase (Invitrogen). Following synthesis, cDNA was purified by using a PCR purification kit (Qiagen) to remove the unincorporated deoxynucloside triphosphates, fluorescent dye, and primers. Equal volumes of cDNA were combined and evaporated to near dryness with an SPD121P Speed Vac (Thermon Savant). For hybridisation to the microarray slides, cDNA was resuspended in an appropriate volume of salt-based hybridization buffer (provided by Ocimum Biosolutions). Prior to addition to the slides, cDNA samples were heated to 95 °C for 3 min, and then placed on ice for no more than 3 min. The slides were placed in MWG Biotech hybridization chambers and incubated for 16 to 24 h in a shaking water bath at 110 rpm and 42 °C. Following incubation , the slides were washed sequentially for 5 min in 2x SSC-1 % sodium dodecyl sulphate, 1x SSC, 0.5x SSC and 0.1x SSC at 37 °C with gentle agitation (1x SSC is 0.15 M NaCl plus 0.015 M sodium citrate). The slides were dried by centrifugation at 254 xg for 5 min and subsequently scanned with an Affymetrix 428 scanner. The average signal intensity and local background correction were obtained by using commercially available software from Biodiscovery, Inc. (Imagine version 4.0, and Genesight, version 3.5). The mean values from each channel were log2 transformed and normalized by using the subtract-by-mean method to remove intensity-dependent effects in the log2 (ratio) values. The Cy3/Cy5 fluorescence ratios were calculated from the normalized values. Biological experiments (i.e. chemostat growth with and without 0.25 mM GSNO addition) were carried out three times and a dye swap was performed for two of the three experiments which provided two technical repeats, one each for two of the three biological repeats. Data from the independent experiments were combined. Genes that were differentially expressed ≥ twofold and displayed and P value of ≤ 0.05 (as determined by a t test) were defined as being statistically significantly 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 ÂºC. 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 Qiagenâs RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. A C. jejuni cgb mutant was grown in two parallel custom-built chemostats based on Sigma Proculture Dynalift spinner flasks with a working volume of 125 ml, and the dilution rate (which at steady state is equal to the specific growth rate) of 0.1 h-1. A gas mix of 10% O2, 10% CO2 and 80% N2 was passed into the head space of the culture vessel at a rate of 0.25 l min-1 to obtain a microaerobic atmosphere, and silicone water jackets maintained the temperature at 42 ÂºC. The flasks were placed on KMO 2 basic IKA-Werke stirrers (arbitrary setting, 260; Scientific Laboratory Supplies), which gaveeffective transfer of O2 from the gaseous atmosphere to the culture by virtue of a stable vortex. A fresh overflow sample was used to check the pH at the time of harvest (which was consistently between 6.6 and 7) and to ensure that there was no contamination by plating a 20 Î¼l sample onto both nutrient agar plates incubated at 37 Â°C at atmospheric oxygen, and Mueller-Hinton plates incubated at 42 Â°C in the microaerophilic work station. When staedy-state was reached, as verified by collecting at least 5 culture volumes, GSNO (final concentration 0.25 mM) was added to one culture. After a further 10 min the 125 ml volume was separated into 3 equal volumes and each was mixed immediately on ice with 3.56 ml 100% ethanol and 185 ml 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. cDNA synthesis was carried out using 12 Âµg of starting material, which was primed with 9 Âµg of pd(N)6 random hexamers (Amersham Biosciences). Reaction mixtures (20 Âµl) containing 0.5 mM ATP, 0.5 mM TTP, 0.5 mM GTP, 0.2 mM CTP, and 1 mM Cy3- or 1 mM Cy5-dCTP were incubated for 2 h at 42 Â°C with 200 U of Superscript II RNase H reverse transcriptase (Invitrogen). Following synthesis, cDNA was purified by using a PCR purification kit (Qiagen) to remove the unincorporated deoxynucloside triphosphates, fluorescent dye, and primers. Equal volumes of cDNA were combined and evaporated to near dryness with an SPD121P Speed Vac (Thermon Savant). For hybridisation to the microarray slides, cDNA was resuspended in an appropriate volume of salt-based hybridization buffer (provided by Ocimum Biosolutions). Prior to addition to the slides, cDNA samples were heated to 95 Â°C for 3 min, and then placed on ice for no more than 3 min. The slides were placed in MWG Biotech hybridization chambers and incubated for 16 to 24 h in a shaking water bath at 110 rpm and 42 Â°C. Following incubation , the slides were washed sequentially for 5 min in 2x SSC-1 % sodium dodecyl sulphate, 1x SSC, 0.5x SSC and 0.1x SSC at 37 Â°C with gentle agitation (1x SSC is 0.15 M NaCl plus 0.015 M sodium citrate). The slides were dried by centrifugation at 254 xg for 5 min and subsequently scanned with an Affymetrix 428 scanner. The average signal intensity and local background correction were obtained by using commercially available software from Biodiscovery, Inc. (Imagine version 4.0, and Genesight, version 3.5). The mean values from each channel were log2 transformed and normalized by using the subtract-by-mean method to remove intensity-dependent effects in the log2 (ratio) values. The Cy3/Cy5 fluorescence ratios were calculated from the normalized values. Biological experiments (i.e. chemostat growth with and without 0.25 mM GSNO addition) were carried out three times and a dye swap was performed for two of the three experiments which provided two technical repeats, one each for two of the three biological repeats. Data from the independent experiments were combined. Genes that were differentially expressed â¥ twofold and displayed and P value of â¤ 0.05 (as determined by a t test) were defined as being statistically significantly differentially transcribed.

Project description:To identify mRNAs associated with human PUM2 protein, we used a modified Ribonucleoprotein-ImmunoPrecipitation Microarray (RIP-Chip) approach on HeLa S3 cancer cells that express PUM2. PUM ribonucleoprotein (RNP) complexes were captured from cell-free extracts with specific anti PUM2 antibody coupled to protein A sepharose beads, and then eluted with SDS-EDTA. To control for non-specifically enriched RNAs, the same procedure was performed with beads that were not coupled with immunoprecipitating antibodies (mock samples). Total RNA was isolated from cell extracts and immunopurified samples with the mirVanaTM PARISTM kit (Ambion). RNA was quantified with a NanoDrop device (Witeg AG). Poly-adenylated RNAs were amplified in the presence of aminoallyl-UTP with Amino Allyl MessageAmp II aRNA kit (Ambion). For this purpose, 500 ng total RNA from extracts and half (50-100 ng) of the immunopurified RNAs were used for amplification. 8 ug of the amplified RNAs (aaRNA) were fluorescently labeled with NHS-monoester Cy3 and Cy5 dyes (GE HealthSciences), except for mock RNA samples, where an aaRNA amount proportional to the yield obtained from corresponding PUM affinity isolates was used.For PUM2 RIPs, we performed four biological replicates but omitted the dye swaps due to the lower aaRNA obtained after amplification (~10 ug aaRNA from PUM2 RIPs, 9 ug aaRNA from mock RIPs). The Cy3- and Cy5-labeled aaRNA samples were mixed and hybridized to human cDNA microarrays. Detailed methods for microarray experiments are available at http://cmgm.stanford.edu/pbrown/protocols/index.html. cDNA microarrays were produced by the Stanford Functional Genomic Facility and contained 43,197 human probes representing 26,524 Unigene cluster IDs (12,466 ENSEMBL annotated genes) spotted on Corning Ultra GAPS slides. Spotted cDNAs were cross-linked with 65 mJ of UV irradiation on slides, which were then post-processed for 1 hour at 42°C in pre-hybridization solution (5x SSC, 0.1% SDS, 0.1 mg/ml BSA), washed twice in 400 ml of 0.1x SSC for 5 min, dunked in 400 ml ultrapure water for 30 sec, and dried by centrifugation at 550 rpm for 5 min. Slides were used the same day. Cy3- and Cy5-labeled aaRNA probes were mixed and applied to arrays in hybridization solution (3x SSC, 20 ug poly(A) RNA [Invitrogen], 20 ug yeast tRNA [Invitrogen], 20 ug Human Cot-1 DNA [Invitrogen], 20 mM HEPES [pH 7.0] and 0.3% SDS) for 18 h at 65°C. The arrays were then washed sequentially in 400 ml of 2x SSC with 0.1% SDS, 1x SSC, and 0.2x SSC. The first wash was performed for 5 min at 65°C, the subsequent washes were performed for 5 min at RT. The arrays were dried by centrifugation and immediately scanned with an AxonScanner 4200A (Molecular Devices). Data were collected using GENEPIX 5.1 (Molecular Devices). Arrays were normalized computationally by the Stanford Microarray Database (SMD). The data were filtered for signal over background of greater than 1.5 in the channel measuring aaRNA from extract, and only features that met these criteria in > 50% of the arrays were included for further analysis. Log2 median ratios were retrieved and exported into Microsoft Excel. To identify transcripts that were specifically enriched by association with PUM2, we performed two class Significance Analysis of Microarrays (SAM) on median centered arrays. A replicate experimental design type is where a series of replicates are performed to evaluate reproducibility or as a pilot study to determine the appropriate number of replicates for a subsequent experiments. Antibody used in IP: 50 ug rabbit anti-PUMILIO 2 (Bethyl Laboratories, #300-202A) Keywords: replicate_design

Project description:This series repressents the data set from the paper "Expression microarray analysis and oligo array CGH of aquired gemcitabine resistance in mouse colon reveals selection for chromosomal aberrations". Biological material: One solid mouse tumor "Colon 26A" was routinely maintained by successive transplantation. A subset of mice with this tumor was treated at the maximum tolerable dosage of Gemcitabine and successively transplanted 5 times and similarly treated. The last passage was completly resistant and designated, "Colon 26G". Expression array: Total RNA was isolated from frozen mouse tumors using Tryzol. Single stranded cDNA was synthetized from 30 mg of total RNA by reverse transcription using aminoallyl labeled dUTP (Ambion). Labelling was performed according to the aminoallyl labeling protocol. Briefly, cDNA was incubated at room temperature for 1 h with fluorolink monofunctional cy5 or cy3 (Amersham) followed by 15 min 4 M hydroxylamine treatment. Uncoupled dyes were removed using Qiaquick PCR purification columns (Qiagen) and mixed with 12 mg poly(dA) (Amersham), 60 mg yeast tRNA (Sigma) and 24 mg Cot-1 DNA (Invitroen). The probe was dissolved in 127 ml hybridization mixture containing 46% formamide, 9.5% dextran sulfate, 2x SSC and 0.2% SDS. The probe was heated to 70°C for 10 min and annealed at 37°C for 1 h. Slides were hybridized for 14 h at 37°C over-night (HyArray 12™, Perkin Elmer). After hybridization the slides were washed in the HybArray 12™ with 50% formamide, 2x SSC, pH 7 at 35°C for 15 min, followed b PI buffer (0.1 M sodium phosphate, 0.1% Igepal Ca630, pH 8) at room temperature and 3 washes of 0.2x SSC, 0.1x SSC and 0.01x SSC at room temperature followed by centrifugation. Arrays were scanned using a laser scanner (ScanArray Express, Perkin Elmer) and analysed using ImaGene version 5.6. Cy5 cy3 ratios are calculating by taking the log2 of the signal mean of each spot minus the median background mean of all spots on the array. This is followed by a standard normalization for spot intensity and calculation of the ratios. Keywords: other

Project description:Ambient temperature affects organisms comprehensively, however cold responses are different among tissues. Here, we adopt a transcript screening approach to explore and compare the cold responses in zebrafish gills and brain. Zebrafish were exposed to cold and the oligonucleotide-based microarray was used to identify cold-induced genes. Principle component analysis (PCA) of the gene expression profiles indicated that gills develop different strategies for the increasing of exposure period while brain relatively remained stable. Combining statistic and clustering methods, we found that gills showed higher protein metabolism and cell activity while brain showed higher stress responses and detoxification during cold acclimation. According to the microarray data sets, we extended the study on ionocyte- and isotocin neuron-related genes in gills and brain, respectively, and found these genes were broadly stimulated by cold. These data suggest that cold activates specific physiological functions in different tissues. Taken together, our results provide molecular evidences to elucidate the cold acclimation in zebrafish gills and brain. Keywords: Time course, Tissue types After the low-temperature treatment, brain and gill tissues dissected from 10 individuals were pooled as a sample and then homogenized in 0.8 ml Trizol reagent (Invitrogen, Carlsbad, CA). 120 individuals (60 for low-temperature treatment and 60 for control) were sacrificed for each microarray hybridization experiment, and another 200 individuals were used for quantitative reverse-transcription polymerase chain reaction. After chloroform extraction, RNA precipitation and ethanol washing, the RNA samples were purified and treated with DNase1 to remove the genomic DNA by using RNeasy Mini Kit (Qiagen, Huntsville, Alabama). The quantity and quality of total RNA were assessed by spectrophotometry and Bioanalyzer (Aglient Technologies, Foster City, CA). The commercial zebrafish 14K oligonucleotides set (MWG Biotech AG, Ebersbach, Germany) were obtained and were printed on UltraGAPS Coated slide (Corning, New York, NY ) with use of the OmniGrid 100 microarrayer (Genomic Solutions, Ann Arbor, MI) according to the manufactureâ??s instructions. The 14,067 oligonucleotides represent 9666 genes (7009 singlet genes and 2657 redundant genes), and the redundancy of this chip is 31 %. The detailed description of the oligonucleotides information can be obtained on the Ocimun Biosolution website. cDNA probes were synthesized and purified by reverse transcription of 20 Î¼g total RNA using a SuperScript indirect cDNA labeling system (Invitrogen) and MinElute PCR purification kit (Qiagen) and were labeled with Alexa 647 dye (cold treatment groups) and Alexa 555 dye (control groups)(Invitrogen), respectively. The zebrafish 14K OciChip array chip was pretreated with 1% bovine serum albumin (BSA) (fraction V), 4x saline-sodium citrate (SSC), and 1% sodium dodecylsulfate (SDS) at 42 Â°C for 45 min, and then hybridized overnight in a cocktail containing 5x Denhardt's solution, 6x SSC, 0.5% SDS, 50% formamide, 50 mM sodium phosphate, and 2 Âµg/Âµl yeast tRNA. Slides were washed with 2x SSC and 0.1% SDS (5 min), 1x SSC and 0.1% SDS (5 min), 0.5x SSC (5 min), and twice with 0.1x SSC (2 min each). Scanning was performed with a Genepix scanner (Molecular Devices, Sunnyvale, CA). The acquired images were analyzed using Genepix and Genespring software (Aglient Technologies, Foster City, CA). The measurements of spots were filtered by flags, and the Lowess normalization was performed after subtraction of the median background. Each experiment contained 3 biological replicates (including 1 dye swap) with different samples. The differentially expressed genes were selected from those with at least 2 of 3 significant signals (ratio > 2 or < 0.5), and then the Significant Analysis of Microarray method (SAM 3.02) was used to determine statistical significances.

Project description:Wild-type Campylobacter jejuni NCTC11168 was grown in 2 homemade, parallel chemostats. Cells were grown in 125 ml volumes of Mueller-Hinton Broth where the growth rate was controlled by the dilution rate (0.1 h-1). A gas mix of 80% nitrogen, 10% carbon dioxide and 10% oxygen was pumped into the head-space of the vessels at a rate of 0.25 l/min to obtain a microaerobic environment and the culture was maintained at 42 ÂºC via a water jacket. Cells were grown as above until steady-state had been reached. At steady-state one of the cultures was exposed to 10 uM NOC-5 & -7 (final concentration) for a period of 10 min. Samples of both the control and stressed cultures were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using Qiagenâ??s RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Equal quantities of RNA from control and GSNO-supplemented cultures were labelled using nucleotide analogues of dCTP containing either Cy3 or Cy5 fluorescent dyes. The average signal intensity and local background correction were obtained using a commercially available software package from Biodiscovery, Inc (Imagene, version 4.0 and GeneSight, version 4). The mean values from each channel were log2 transformed and normalised using the Lowess method to remove intensity-dependent effects in the log2(ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalized values. C. jejuni NCTC11168 was grown in two parallel custom-built chemostats based on Sigma Proculture Dynalift spinner flasks with a working volume of 125 ml, and the dilution rate (which at steady state is equal to the specific growth rate) of 0.1 h-1. A gas mix of 10% O2, 10% CO2 and 80% N2 was passed into the head space of the culture vessel at a rate of 0.25 l min-1 to obtain a microaerobic atmosphere, and silicone water jackets maintained the temperature at 42 ÂºC. The flasks were placed on KMO 2 basic IKA-Werke stirrers (arbitrary setting, 260; Scientific Laboratory Supplies), which gaveeffective transfer of O2 from the gaseous atmosphere to the culture by virtue of a stable vortex. A fresh overflow sample was used to check the pH at the time of harvest (which was consistently between 6.6 and 7) and to ensure that there was no contamination by plating a 20 Î¼l sample onto both nutrient agar plates incubated at 37 Â°C at atmospheric oxygen, and Mueller-Hinton plates incubated at 42 Â°C in the microaerophilic work station. When staedy-state was reached, as verified by collecting at least 5 culture volumes, NOC-5 & -7 (final concentration 10 uM) was added to one culture. After a further 10 min the 125 ml volume was separated into 3 equal volumes and each was mixed immediately on ice with 3.56 ml 100% ethanol and 185 ml 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. cDNA synthesis was carried out using 12 Âµg of starting material, which was primed with 9 Âµg of pd(N)6 random hexamers (Amersham Biosciences). Reaction mixtures (20 Âµl) containing 0.5 mM ATP, 0.5 mM TTP, 0.5 mM GTP, 0.2 mM CTP, and 1 mM Cy3- or 1 mM Cy5-dCTP were incubated for 2 h at 42 Â°C with 200 U of Superscript II RNase H reverse transcriptase (Invitrogen). Following synthesis, cDNA was purified by using a PCR purification kit (Qiagen) to remove the unincorporated deoxynucloside triphosphates, fluorescent dye, and primers. Equal volumes of cDNA were combined and evaporated to near dryness with an SPD121P Speed Vac (Thermon Savant). For hybridisation to the microarray slides, cDNA was resuspended in an appropriate volume of salt-based hybridization buffer (provided by Ocimum Biosolutions). Prior to addition to the slides, cDNA samples were heated to 95 Â°C for 3 min, and then placed on ice for no more than 3 min. The slides were placed in MWG Biotech hybridization chambers and incubated for 16 to 24 h in a shaking water bath at 110 rpm and 42 Â°C. Following incubation , the slides were washed sequentially for 5 min in 2x SSC-1 % sodium dodecyl sulphate, 1x SSC, 0.5x SSC and 0.1x SSC at 37 Â°C with gentle agitation (1x SSC is 0.15 M NaCl plus 0.015 M sodium citrate). The slides were dried by centrifugation at 254 xg for 5 min and subsequently scanned with an Affymetrix 428 scanner. The average signal intensity and local background correction were obtained by using commercially available software from Biodiscovery, Inc. (Imagine version 4.0, and Genesight, version 3.5). The mean values from each channel were log2 transformed and normalized by using the subtract-by-mean method to remove intensity-dependent effects in the log2 (ratio) values. The Cy3/Cy5 fluorescence ratios were calculated from the normalized values. Biological experiments (i.e. chemostat growth with and without 0.25 mM GSNO addition) were carried out three times and a dye swap was performed for two of the three experiments which provided two technical repeats, one each for two of the three biological repeats. Data from the independent experiments were combined. Genes that were differentially expressed â?¥ twofold and displayed and P value of â?¤ 0.05 (as determined by a t test) were defined as being statistically significantly differentially transcribed.

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Synechocystis sp. PCC 6803 response to inorganic carbon limitation

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