Project description:Transcript abundance in Escherichia coli O157:H7 was determined in the presence or absence of pulsed expression of the small RNA, AsxR. AsxR was cloned under the control the arabinose inducible promoter Para. Escherichia coli O157:H7 str. TUV93-0 with pAsxR or empty vector was cultured in MEM-HEPES media to an OD600 of 0.8 and 0.2% arabinose added. 10min after addition of arabinose 10ml of cells were harvested and and pellets resuspended in 1ml of Trizol and total RNA isolated. RNAs were labelled using the SuperScript Plus indirect cDNA labelling System. Triplicate control RNAs were pooled and hybridised to seperate AsxR test RNAs on three microarays. Arrays were hybridised using the Maui hybridisation platform and Scann using and Axon Autoloader Scanner. GenePix software was used to analyse images and GPR files were analysed using Genespring 7.3.1.
Project description:Escherichia coli O157 presents a number of specific problems in terms of food safety and public health. It has been found that E. coli O157 is more resistant to a number of the stresses encountered during food production such as heat, pH and osmotic shock. This greater resistance is thought to contribute to the low infectious dose of E. coli O157 (<100 organisms). Moreover, E. coli O157 is associated with debilitating conditions such as haemorrhagic colitis and haemoytic uraemic syndrome, particularly in children and the elderly. We have been studying the stress responses of E. coli O157:H7 (Sakai) and comparing with a commensal strain of E. coli K-12, MG1655. We found that E. coli O157 (Sakai) is more resistant to heat stress than MG1655. A microarray study of these strains subjected to sub-lethal heat-stress at 45°C was carried out. In E. coli O157 (Sakai), 380 genes responded significantly to the treatment compared to 410 genes in MG1655. Overnight cultures of E. coli O157 (Sakai) and E. coli K-12 MG1655 were grown in Neidhardt's EZ Rich Defined Medium and diluted 1:100 in 50 ml fresh medium in 125 ml Ehrlenmeyer flasks. The cultures were shaken at 37°C until the optical density (OD600) reached 0.4. Each culture was divided into 2 equal parts in identical flasks. One flask flask was transferred to a shaking water bath and incubated at 45°C for 10 min; the other flask was incubated at 37°C for 10 min. After incubation, the cultures were transferred to 50 mL centrifuge tubes and treated with RNAprotect™ to stabilise the mRNA. The experiment was performed 3 times on different days. Six custom-made microarray slides were used in this study; each slide was hybridised with labelled cDNA made from untreated and heated E. coli O157 (Sakai) or MG1655.
Project description:The transcriptional profile of Escherichia coli O157 treated with small molecule inhibitors of type III secretion was determined. Four variations of the small molecule inhibitor were assessed for global changes in transcription by treating cells with 20uM of inhibitor or an equivalent volume of DMSO (inhibitor solvent). Keywords: treatment, dose, Cy3, Cy5, 2-colour For each inhibitor, biological tripicates of treated (20uM inhibitor in DMSO) and untreated (DMSO only) cultures were grown in 25ml of MEM-HEPES supplemented with 0.1% Glucose and 250nM Fe(NO3)2. RNA was extracted from 15ml of culture at OD 0.7 and labeled with Cy5 (treated) and Cy3 (untreated) (excepting ME0055 that was performed as a dye swap). Labeled untreated RNA was pooled prior to hybridisation. Treated RNA (biological replicates) and pooled untreated RNA was hybridised to microarray slides. Slides were scanned using an Axon 4100A scanner and data processed using Genespring GX.
Project description:Time series of infection of Sulfolobus solfataricus strain 2-2-12 cells infected with STIV are compared with uninfected cells over 32 h. Two-condition experiment, Control vs. Infected cells sampled at 5 time points (0, 8, 16, 24, 32 h post infection). Biological replicates: 3 control, 3 infected, paired samples independently grown. One replicate per array. Dye swaps.
Project description:We used microarray CGH analysis with a tiling path BAC DNA microarray to profile DNA copy number alterations in 164 serous ovarian adenocarcinomas. Survival probabilities modelled by proportional hazards were used to stratify cases into good, intermediate or poor survival groups. Comparison of aCGH data from these groups was used to identify genomic alterations associated with patient survival. A total of 984 cases of serous ovarian adenocarcinoma from three different studies were combined and Cox proportional hazards used to model survival using patient age, tumour stage and residual disease status as covariates. Survival probabilities (Pr) were extracted for all cases and used to stratify 384 cases for which microarray CGH data was available. From these, we identified 70 cases with poor survival (Pr>0.784) and 70 cases with good survival (Pr<0.35). aCGH data from these cases was provided to an iterative Support Vector Machine (SVM) routine to detect copy number changes associated with survival. Candidate regions were then validated by survival analysis in all 384 cases for which aCGH data was available. This series contains aCGH data from 164 tumours from the MALOVA collection.
Project description:Transcriptional profile of the rocG gudB double null mutant during log growth phase in LB medium. Bacillus subtilis W168, WT vs. delta-rocG delta-gudB. The experiment was conducted two times using three independent total RNA preparations (biological triplicates). For each paried comparison, WT was labeled with Alexa Fluor 555 and the rocG gudB double mutant was with Alexa Fluor 647.
Project description:Chickens divergently selected for either high abdominal fat content (fat genotype) or low abdominal fat content (lean genotype) at SRA-INRA, France were used to profile hepatic gene expression during juvenile development (1 to 11 weeks of age) and to identify differentially expressed genes associated with genotype and age. The fat line (FL) and lean line (LL) chickens are different in various phenotypic and metabolic measurements, including abdominal fatness, plasma glycemia and T3. The FL and LL chickens represent unique models for characterizing biomedical and agricultural traits. The Del-Mar 14K Chicken Integrated Systems microarrays were used for a transcriptional scan in liver during juvenile development using a balanced block hybridization design. Log2-transformed fluorescence intensities were analyzed with a two-stage mixed model. A total of 905 differentially expressed "functional" genes were identified (FDR<0.10). The greatest number of differentially expressed genes (400) was detected at 7 weeks of age. The differentially expressed genes include metabolic enzymes, acute phase proteins, growth factors, immune factors and transcription factors involved in various pathways. Several of the functional genes are also identified as positional candidate genes within QTLs in an F2 population established from an intercross between the FL and LL lines. A balance block design was used for microarray hybridizations, where half of the birds of each genotype and age were labeled with Alexa Flour 647 (red) and the other half with Alexa Flour 555 (green). Four biological replicates were used for each genotype (FL or LL) at six different ages (1, 3, 5, 7, 9 and 11 wk).
Project description:ra07-03_aba4 - aba4/1 - Identification of genes deregulated in aba4 mutant or overexpressers. - Comparison of different genotypes to wild type Col-0: aba4-3 mutant, two independent 35S-ABA4 transgenic lines and two independent 35S-NCED6 transgenic lines. Keywords: gene knock in (transgenic),gene knock out 6 dye-swap - CATMA arrays