Biomedical subjects

Wesley B Bruce

Publications and source records attributed to Wesley B Bruce.

2 recordsLinked to original sources

PubMed2003

Expression profiling using cDNA microarrays.

Microarray technology has become increasingly useful in measuring expression levels of a large number of genes and part of a repertoire of functional genomic tools. We describe the methods of cDNA microarray preparation, the use, data collection, and initial data processing. The cDNA fragments are first prepared by polymerase chain reaction (PCR), and then attached to a solid substrate, such as a chemically treated glass slide. Robotic machines spot the prepared cloned cDNA samples in a miniaturized gridded pattern, so that nanoliter amounts of tens of thousands cDNA samples are bound to a single 7.5 x 2.5 cm glass slide. Probes are generated from RNA samples of test and control tissues by incorporating Cyanine dyes (Cy3 or Cy5) in reverse-transcribed products. Probes from a test sample are labeled with one of two Cy dyes and mixed in equal amounts with probes from a control sample labeled with the second dye. The glass slides containing the cDNA microarray are hybridized with the mixed Cy-labeled probes, washed, dried, and scanned using laser scanners with an optimized wavelength to excite each Cy dye. The emission image patterns for each dye are captured by a digital camera using micro-optics and processed into numerical values that positively correlate with quantitative levels of mRNA for each cDNA spot on the slide. The collected data is then further processed, normalized across experiments, and examined via numerous statistical and mathematical approaches to infer changes in expression levels of particular genes due to the treatment tested.

DNA, Complementary↗

PubMed2002

Molecular and physiological approaches to maize improvement for drought tolerance.

Average maize yields have increased steadily over the years in the USA and yet the variations in harvestable yield have also markedly increased. Much of the increase in yield variability can be attributed to (1) varying environmental stress conditions; (2) improved nitrogen inputs and better weed control; and (3) continuing sensitivity of different maize lines to the variation in input supply, especially rainfall. Drought stress alone can account for a significant percentage of average yield losses. Yet despite variable environments, new commercially available maize hybrids continue to be produced each year with ever-increasing harvestable yield. Since many factors contribute to high plant performance under water deficits, efforts are being made to elucidate the nature of water-stress tolerance in an attempt to improve maize hybrids further. Such factors include better partitioning of biomass to the developing ear resulting in faster spikelet growth and improved reproductive success. An emphasis on faster spikelet growth rate may result in a reduction in the number of spikelets formed on the ear that facilitates overall seed set by reducing water and carbon constraints per spikelet. To understand the molecular mechanisms for drought tolerance in improved maize lines better, a variety of genomic tools are being used. Newer molecular markers and comprehensive gene expression profiling methods provide opportunities to direct the continued breeding of genotypes that provide stable grain yield under widely varied environmental conditions.

Acclimatization↗