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Abstract

A high-capacity system was developed to monitor the expression of many genes in parallel. Microarrays prepared by high-speed robotic printing of complementary DNAs on glass were used for quantitative expression measurements of the corresponding genes. Because of the small format and high density of the arrays, hybridization volumes of 2 microliters could be used that enabled detection of rare transcripts in probe mixtures derived from 2 micrograms of total cellular messenger RNA. Differential expression measurements of 45 Arabidopsis genes were made by means of simultaneous, two-color fluorescence hybridization.

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... The other principle array technology is that of Affymetrix. A review of array technologies can be found in Schena et al. (1995), Kehoe (1999), and Deyholos and Galbraith (2001). Although micro arrays are typically used to produce an mRNA profile, the technology can be adapted to investigate genomic DNA (therefore becoming genomics as opposed to transcriptomics). ...
... used. An array is considered to be high density when the elements have a centrecentre spacing of < 0.5 mm (Schena et al. 1995). Typically, glass slides of similar dimensions to those of a typical microscope slide are used as the solid substrate. ...
Thesis
p>The genetic nature of tree adaptation to drought stress was examined by utilising variation in the drought response of an F<sub>2</sub> mapping population from a cross between Populus trichocarpa (93-968) and P. deltoides Bart (ILL-129) known to be highly divergent for a vast range of phenotypic traits. Phenotyping, QTL analysis and microarray experiments were combined to demonstrate that “genetical genomics” can be used to provide information on adaptation at the species level. The grandparents and F<sub>2</sub> population were subjected to soil drying and contrasting responses to drought across genotypes including for leaf coloration, expansion, and abscission were observed and QTL for these traits were identified. A subset of extreme genotypes exhibiting extreme sensitivity and insensitivity to drought on the basis of abscission were defined and microarray experiments were conducted on these genotypes and the grandparents. The different groups induced a different set of genes; 215 and 125 genes differed in their expression response in control and drought respectively, suggesting species adaptation at the gene expression level. Genes preferentially expressed in drought resistance genotypes overlapped with genes expressed in dormant tissues whereas genes involved in meristem function had a lower expression. Co-location of differentially expressed genes with drought specific and drought responsive QTLs was identified and these represent candidate genes contributing to the variation in drought response.</p
... The development of micro arrays was pioneered by Schena et al. (1995) at Stanford ...
Thesis
p>This study integrates three methods for detection of an induced response to aphid feeding. Firstly, it is shown that volatile organic compounds emitted from wild cabbage infested with the cabbage aphid Brevicoryne brassicae attract the aphid parasitoid Diaeretiella rapae and could constitute a reliable and detectable cue during parasitoid host foraging. It is found that there is no difference in attraction to aphid-infested plants when comparing field-collected and lab-reared parasitoids. Secondly, collection and analysis of compounds emitted from the aphid and Plutella xylostella damaged plants reveals several compounds exhibiting significant induction when compared to uninfested plants. Univariate techniques and multivariate canonical discriminant analysis reveal distinct volatile profiles contain several terpenes and 3-butenyl isothiocyanate as induced compounds that could be involved in the attraction of the parasitoid. It is proposed that this multivariate technique may closer resemble the method of signal recognition used by foraging insects. Finally, global gene expression analysis using Arabidopsis thaliana microarrays coupled to a Brassica oleracea specific software filter is used to assay the expression of genes induced by aphid and Plutella feeding. These experiments reveal the aphid- and Plutella- related induction of genes involved in isoprenoid biosynthesis, involvement of the octadecanoid pathway following Plutella feeding and that although the genes induced are different, number of genes induced by the different herbivores is roughly equal. AFLP analysis illustrates the high degree of genotypic variation in wild Brassica populations when compared to crop cultivars and Arabidopsis thaliana . This suggests that the wild populations are segregating with a high level of gene flow between populations.</p
... In the mid-1990s, DNA and oligonucleotide microarray technology started to revolutionalize studies of gene expression enabling analysis of the activity of tens of thousands of transcripts at the same time. [1][2][3] In the field of neurosciences and neurology, this technology began to be first employed during the late 1990s and immediately raised high expectations for its capacity to increase molecular understanding in behavior and disease. 4,5 It soon became evident that the sensitive technology had pitfalls and was to be used carefully. ...
... Non covalent methods and hydrophobic interactions result from thin film deposition onto the solid support prior to spotting. Schena et al./ (1995) describes the use of polylysine to promote DNA binding. Although fairly efficient, these can strip array from the surface under extremes of temperature and salt concentration thus removing the spotted sample from the array surface (Allemand et al./ 1997). ...
Thesis
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