Detection of two orchid viruses using quartz crystal microbalance-based DNA biosensors.

ABSTRACT We have developed a piezoelectric DNA-sensor based on DNA-RNA hybridization for the detection of two orchid viruses, Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV). Specific oligonucleotide probes modified with a mercaptohexyl group at the 5'-phosphate end were directly immobilized onto 10-MHz AT-cut quartz crystal microbalance (QCM). QCMs coated with such oligonucleotide probes were exposed to test solutions containing viral RNA for hybridization.

15000 unique zebrafish EST clusters and their future use in microarray for profiling gene expression patterns during embryogenesis.

A total of 15590 unique zebrafish EST clusters from two cDNA libraries have been identified. Most significantly, only 22% (3437) of the 15590 unique clusters matched 2805 (of 15200) clusters in the Danio rerio UniGene database, indicating that our EST set is complementary to the existing ESTs in the public database and will be invaluable in assisting the annotation of genes based on the upcoming zebrafish genome sequence. Blast search showed that 7824 of our unique clusters matched 6710 known or predicted proteins in the nonredundant database.

Detection of two orchid viruses using quartz crystal microbalance (QCM) immunosensors.

Quartz crystal microbalance (QCM) immunosensors are based on the principle that adsorption of substances on the surface of a quartz crystal changes its resonance oscillation frequency. A QCM immunosensor was developed for the detection of both cymbidium mosaic potexvirus (CymMV) and odontoglossum ringspot tobamovirus (ORSV) by pre-coating the QCMs with virus-specific antibodies. Upon binding of virions in either purified form or crude sap of infected orchids with the immobilised virus antibodies, the increase in mass at the QCM surface resulted in a reduction in the frequency of resonance oscillation in a manner dependent upon the amount of virus bound.