Coral reef fishes are expected to experience rising sea surface temperatures due to climate change. How well tropical reef fishes will respond to these increased temperatures and which genes are important in the response to elevated temperatures is not known. Microarray technology provides a powerful tool for gene discovery studies, but the development of microarrays for individual species can be expensive and time-consuming. In this study, we tested the suitability of a Danio rerio oligonucleotide microarray for application in a species with few genomic resources, the coral reef fish Pomacentrus moluccensis. Results from a comparative genomic hybridization experiment and direct sequence comparisons indicate that for most genes there is considerable sequence similarity between the two species, suggesting that the D. rerio array is useful for genomic studies of P. moluccensis. We employed this heterologous microarray approach to characterize the early transcriptional response to heat stress in P. moluccensis. A total of 111 gene loci, many of which are involved in protein processing, transcription, and cell growth, showed significant changes in transcript abundance following exposure to elevated temperatures. Changes in transcript abundance were validated for a selection of candidate genes using quantitative real-time polymerase chain reaction. This study demonstrates that heterologous microarrays can be successfully employed to study species for which specific microarrays have not yet been developed, and so have the potential to greatly enhance the utility of microarray technology to the field of environmental and functional genomics.

Solid-phase (SP) polymerase chain reaction (PCR) is an increasingly popular tool used to produce immobilized DNA for a variety of applications, including high-throughput DNA sequencing and SNP analysis. Despite its usefulness, the mechanism of DNA amplification using immobilized primers has not been thoroughly explored. Herein, we describe a SP-PCR process that was designed to explore and better understand some limitations of SP-DNA amplification. The rate of SP-DNA amplification was measured, and the ability to exponentially amplify DNA on a surface was demonstrated. Approximately 50 amol of DNA was amplified to detectable levels using SP-PCR. The mechanism and some limitations of the reaction were investigated by measuring the density of the primer on the surface prior to amplification and the amount of immobilized amplicon produced after SP-PCR. This enabled some of the practical limitations of the reaction to be addressed within a logical theoretical framework.

Not bad at all: A simple biological circuit composed of two integrated molecular switches was developed for the detection and amplification of a specific nucleic acid in a biological extract. The nucleic acid is recognized by a molecular beacon, then a DNA polymerase and nicking endonuclease are used to rapidly amplify the signal for sensitive detection of the nucleic acid.

Depending on the cellular context, lithium chloride can lead to enhanced proliferation, cell cycle arrest or apoptosis in mammalian cells. Although substantial work has been made to elucidate the downstream events in the case of lithium chloride-induced cellular proliferation, the molecular response to lithium chloride treatment in the apoptotic scenario is largely undefined. We have used quadruplicate human cDNA arrays with 8000 targets to analyze the early gene response in cultures of human T/C28a cells that undergo apoptosis in response to 20 mM lithium chloride treatment. Incubation of cell cultures with 20 mM lithium chloride for five hours caused alterations in the steady-state mRNA levels of a large number of genes. RT-PCR and real-time RT-PCR confirmed the array results for ten of eleven selected targets. In addition to one protein primarily associated with apoptosis, genes identified as differentially expressed based on microarray data mainly encode proteins involved in basic cellular functions such as signaling, cell cycle control and growth, cell-cell interaction, solute transport and transcription control. We present a list of 50 genes that were differentially expressed in response to lithium chloride treatment and which may represent a reference for further studies to define the pathways governing the apoptotic response to lithium chloride.

Ein einfacher Biochip aus zwei integrierten molekularen Schaltern ermöglicht den Nachweis und die Vervielfältigung spezifischer Nucleinsäuren in biologischen Extrakten. Die Nucleinsäure wird mithilfe eines Beacons detektiert, anschließend werden eine DNA‐Polymerase und Nicking‐Endonuclease zur schnellen Signalverstärkung für den empfindlichen Nucleinsäurenachweis verwendet.