Project description:This study was conducted to evaluate the efficiency of cross-species detection in Barley1 GeneChip array. We hybridized cRNA derived from first leaves of barley green seedlings (as a control), as well as the same stage of seedling leaf from representative genotypes of wheat, oat, rice, maize, and sorghum. Ten to twenty seedlings for each species were harvested and pooled for RNA preparation, labeling, and hybridization. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Rico Caldo. The equivalent experiment is BB1 at PLEXdb.]
Project description:This study was conducted to evaluate the efficiency of cross-species detection in Barley1 GeneChip array. We hybridized cRNA derived from first leaves of barley green seedlings (as a control), as well as the same stage of seedling leaf from representative genotypes of wheat, oat, rice, maize, and sorghum. Ten to twenty seedlings for each species were harvested and pooled for RNA preparation, labeling, and hybridization. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Rico Caldo. The equivalent experiment is BB1 at PLEXdb.] species: Barley(2-replications); species: Wheat(2-replications); species: Oat(2-replications); species: Sorghum(2-replications); species: Corn(2-replications); species: Rice(2-replications)
Project description:The objective of this work was to determine the effectiveness of cross-hybridization of gDNA from five native soil nematodes to an Affymetrix Caenorhabditis elegans tiling array. Cross-hybridization experiments using C. briggsae, for which genome information is available, allowed hybridisation intensities to be correlated with known sequence differences. Initial analysis of data by conventional array-based Comparative Genomic Hybridization (aCGH) techniques at the chip level lead to misleading results due to an artefact from the combination of scaling, bandwidth smoothing, and differential GC content in exon and intron regions. To circumvent this artefact, individual probes were instead normalized and centered by adjusting for probe-specific thermodynamic binding affinity. However, cross-hybridization of C. briggsae DNA revealed that the resultant probe intensities alone were still uncorrelated to sequence similarity below 90% identity. Below 90% similarity, all probes hybridize uniformly poorly, and above 90% similarity the hybridization differences are not large enough to detect over background, therefore, no 'threshold' ratio of hybridization intensity was successful at identifying probes with similarity to the heterologous genome. In light of the observations described here, we suggest that the criteria for replication and verification of gene expression profiles generated from cross-species microarray hybridizations be more stringent than typically adopted for con-specific hybridizations.
Project description:Gene expression analysis to compare control cells and sorted cells We transfected cDNA of human umbilical vein endothelial cells into rat myeloma cells, and sorted cells bound to patient IgG. Sorted cells were analyzed using the Affymetrix Human Genome U133 Plus 2.0 Array to investigate the cDNA inserted into the sorted cells. Array data was processed by Affymetrix GeneChip Command Console Software and Affymetrix Expression Console Software. No techinical replicates were performed.
Project description:The objective of this work was to determine the effectiveness of cross-hybridization of gDNA from five native soil nematodes to an Affymetrix Caenorhabditis elegans tiling array. Cross-hybridization experiments using C. briggsae, for which genome information is available, allowed hybridisation intensities to be correlated with known sequence differences. Initial analysis of data by conventional array-based Comparative Genomic Hybridization (aCGH) techniques at the chip level lead to misleading results due to an artefact from the combination of scaling, bandwidth smoothing, and differential GC content in exon and intron regions. To circumvent this artefact, individual probes were instead normalized and centered by adjusting for probe-specific thermodynamic binding affinity. However, cross-hybridization of C. briggsae DNA revealed that the resultant probe intensities alone were still uncorrelated to sequence similarity below 90% identity. Below 90% similarity, all probes hybridize uniformly poorly, and above 90% similarity the hybridization differences are not large enough to detect over background, therefore, no 'threshold' ratio of hybridization intensity was successful at identifying probes with similarity to the heterologous genome. In light of the observations described here, we suggest that the criteria for replication and verification of gene expression profiles generated from cross-species microarray hybridizations be more stringent than typically adopted for con-specific hybridizations. Genomic DNA from Caenorhabditis elegans N2 (Bristol), C. elegans CB4856 (Hawaiian), C. briggsae AF16, Oscheius tipulae KS585, Oscheius FVV-2 KS555, Mesorhabditis sp. KS587, Acrobeloides sp. KS586, and Chiloplacus sp. KS584 were hybridized onto C. elegans Affymetrix tiling array (two replicate chips were performed for each species).
Project description:The full genome sequencing of the filamentous fungi Aspergillus nidulans, Aspergillus niger and Aspergillus oryzae has opened the possibilities for studying the cellular physiology of these fungi on a systemic level. As a tool to explore this, we are presenting an Affymetrix GeneChip developed for transcriptome analysis of any of the three above-mentioned aspergilli. Transcriptome analysis of triplicate batch cultivations of all three aspergilli on glucose-and xylose media has been performed, and used to validate the performance of the micro array. By doing gene comparisons of all three species, and cross-analysing this with the expression data, 23 genes, including the xylose transcriptional activator XlnR, have been identified to be a conserved response across the Aspergillus sp. Promoter analysis of the upregulated genes in all three species suggest the XlnR-binding site to be 5’-GGNTAAA-3’. We are thus presenting a validated tool for transcription analysis of three Aspergillus species and a methodology for comparative transcriptomics. Keywords: Physiological response
Project description:The full genome sequencing of the filamentous fungi Aspergillus nidulans, Aspergillus niger and Aspergillus oryzae has opened the possibilities for studying the cellular physiology of these fungi on a systemic level. As a tool to explore this, we are presenting an Affymetrix GeneChip developed for transcriptome analysis of any of the three above-mentioned aspergilli. Transcriptome analysis of triplicate batch cultivations of all three aspergilli on glucose-and xylose media has been performed, and used to validate the performance of the micro array. By doing gene comparisons of all three species, and cross-analysing this with the expression data, 23 genes, including the xylose transcriptional activator XlnR, have been identified to be a conserved response across the Aspergillus sp. Promoter analysis of the upregulated genes in all three species suggest the XlnR-binding site to be 5’-GGNTAAA-3’. We are thus presenting a validated tool for transcription analysis of three Aspergillus species and a methodology for comparative transcriptomics. Keywords: Physiological response