Assessing the importance of target type for oligonucleotide microarray experiments
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PROVIDER: PRJNA131559 | ENA |
REPOSITORIES: ENA
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Project description:In order to assess the effect on signal variability of the type of target used for oligonucleotide microarray experiments, we hybridized double and single stranded DNA of three genes on a Nimblegen High Density microarray. This slide carries specific probes (two lengths: 30 and 50 nucleotides, for a total of 7456 probes) targeting every region of selected genes.
2010-07-27 | GSE23168 | GEO
Project description:In order to assess the effect on signal variability of the type of target used for oligonucleotide microarray experiments, we hybridized double and single stranded DNA of three genes on a Nimblegen High Density microarray. This slide carries specific probes (two lengths: 30 and 50 nucleotides, for a total of 7456 probes) targeting every region of selected genes. Probes of 30 nucleotides and 50 nucleotides, covering the full length of three genes (ahdA1C, mmoC and vcrA) by a one nucleotide step, were designed and in situ synthesized in six replicates on a 4*72K Nimblegen Custom Microarray. Double and single stranded DNA of the three genes were hybridized as target.
2010-07-27 | E-GEOD-23168 | biostudies-arrayexpress
Project description:Legionella ITS oligonucleotide microarray
| PRJNA263045 | ENA
Project description:BACKGROUND: High-throughput, parallel gene expression analysis by means of microarray technology has become a widely used technique in recent years. There are currently two main dye-labelling strategies for microarray studies based on custom-spotted cDNA or oligonucleotides arrays: (I) Dye-labelling of a single target sample with a particular dye, followed by subsequent hybridisation to a single microarray slide, (II) Dye-labelling of two different target samples with two different dyes, followed by subsequent co-hybridisation to a single microarray slide. The two dyes most frequently used for either method are Cy3 and Cy5. We propose and evaluate a novel experiment set-up utilising three differently labelled targets co-hybridised to one microarray slide. In addition to Cy3 and Cy5, this incorporates Alexa 594 as a third dye-label. We evaluate this approach in line with current data processing and analysis techniques for microarrays, and run separate analyses on Alexa 594 used in single-target, dual-target and the intended triple-target experiment set-ups (a total of 18 microarray slides). We follow this by pointing out practical applications and suitable analysis methods, and conclude that triple-target microarray experiments can add value to microarray research by reducing material costs for arrays and related processes, and by increasing the number of options for pragmatic experiment design. RESULTS: The addition of Alexa 594 as a dye-label for an additional--third--target sample works within the framework of more commonplace Cy5/Cy3 labelled target sample combinations. Standard normalisation methods are still applicable, and the resulting data can be expected to allow identification of expression differences in a biological experiment, given sufficient levels of biological replication (as is necessary for most microarray experiments). CONCLUSION: The use of three dye-labelled target samples can be a valuable addition to the standard repertoire of microarray experiment designs. The method enables direct comparison between two experimental populations as well as measuring these two populations in relation to a third reference sample, allowing comparisons within the slide and across slides. These benefits are only offset by the added level of consideration required in the experimental design and data processing of a triple-target study design. Common methods for data processing and analysis are still applicable, but there is scope for the development of custom models for triple-target data. In summary, we do not consider the triple-target approach to be a new standard, but a valuable addition to the existing microarray study toolkit.
| S-EPMC365026 | biostudies-literature
Project description:In this study we evaluate the Swine Protein-Annotated Oligonucleotide Microarray by profiling the expression of transcripts in four porcine tissues. We validate the hybridization results by comparative analysis of expression in human orthologs, confirm expression patterns for a subset of genes by QPCR, and assess the usefulness of designed control oligonucleotides. Simple descriptive diagnostic analyses of PM/MM probe sets introduced in this paper are useful to detect non-specific hybridization. Using comparative transcriptional profiling, we found that the microarray data correlate to QPCR data for most genes detected as differentially expressed using the microarray platform. Moreover, comparison to human ortholog expression confirmed the utility of experiments based on this array in swine species as a biomedical model for human tissue specific expression.
2008-11-04 | GSE13095 | GEO
Project description:BACKGROUND: Microarray comparative genomic hybridization (CGH) is currently one of the most powerful techniques to measure DNA copy number in large genomes. In humans, microarray CGH is widely used to assess copy number variants in healthy individuals and copy number aberrations associated with various diseases, syndromes and disease susceptibility. In model organisms such as Caenorhabditis elegans (C. elegans) the technique has been applied to detect mutations, primarily deletions, in strains of interest. Although various constraints on oligonucleotide properties have been suggested to minimize non-specific hybridization and improve the data quality, there have been few experimental validations for CGH experiments. For genomic regions where strict design filters would limit the coverage it would also be useful to quantify the expected loss in data quality associated with relaxed design criteria. RESULTS: We have quantified the effects of filtering various oligonucleotide properties by measuring the resolving power for detecting deletions in the human and C. elegans genomes using NimbleGen microarrays. Approximately twice as many oligonucleotides are typically required to be affected by a deletion in human DNA samples in order to achieve the same statistical confidence as one would observe for a deletion in C. elegans. Surprisingly, the ability to detect deletions strongly depends on the oligonucleotide 15-mer count, which is defined as the sum of the genomic frequency of all the constituent 15-mers within the oligonucleotide. A similarity level above 80% to non-target sequences over the length of the probe produces significant cross-hybridization. We recommend the use of a fairly large melting temperature window of up to 10 C, the elimination of repeat sequences, the elimination of homopolymers longer than 5 nucleotides, and a threshold of -1 kcal/mol on the oligonucleotide self-folding energy. We observed very little difference in data quality when varying the oligonucleotide length between 50 and 70, and even when using an isothermal design strategy. CONCLUSIONS: We have determined experimentally the effects of varying several key oligonucleotide microarray design criteria for detection of deletions in C. elegans and humans with NimbleGen's CGH technology. Our oligonucleotide design recommendations should be applicable for CGH analysis in most species.
2008-07-26 | GSE12208 | GEO
Project description:In this report, we have developed a rapid oligonucleotide microarray detection technique to identify the most common ten Legionella spp.. The sensitivity of the detection was at 1.0 ng with genomic DNA or 13 CFU/100 mL with Legionella cultures. The microarray detected seven air conditioner-condensed water samples with 100% accuracy, validating the technique as a promising method for applications in basic microbiology, clinical diagnosis, food safety, and epidemiological surveillance. The phylogenetic study based on the ITS has also revealed interestingly that the non-pathogenic L. fairfieldensis is the closest to L. pneumophila than the nine other pathogenic Legionella spp..
2014-10-04 | GSE61962 | GEO
Project description:An experimental strategy for quality control of antibody microarray analyses is proposed. The method utilizes proteins that are prepared for regular antibody microarray experiments. There is no need to use exogenous positive or negative reference markers and no need to determine the absolute concentration of each individual protein in the sample. Validation experiments support the basic principle of the proposed approach. This method can be a useful tool for assessing the outcome accuracy of microarray experiments.
| S-EPMC2291551 | biostudies-literature
Project description:We introduce a general technique for making statistical inference from clustering tools applied to gene expression microarray data. The approach utilizes an analysis of variance model to achieve normalization and estimate differential expression of genes across multiple conditions. Statistical inference is based on the application of a randomization technique, bootstrapping. Bootstrapping has previously been used to obtain confidence intervals for estimates of differential expression for individual genes. Here we apply bootstrapping to assess the stability of results from a cluster analysis. We illustrate the technique with a publicly available data set and draw conclusions about the reliability of clustering results in light of variation in the data. The bootstrapping procedure relies on experimental replication. We discuss the implications of replication and good design in microarray experiments.
| S-EPMC55356 | biostudies-literature