In high-throughput DNA analysis, any technological advance that can eliminate tedious liquid-handling techniques is a welcome one. Carlsbad, Calif.-based Invitrogen was the first company to offer bufferless, precast agarose gel electrophoresis with its original robot-compatibleE-Gel® system. Now the company has improved on this technology with the robot-compatible E-Gel 96 High-Throughput Agarose Electrophoresis System of gels and mother and daughter bases. The system speeds up electrophor

Recent months have seen a surge of activity in the field of protein microarrays. No wonder: Gene expression-profiling is faster and more powerful thanks to improvements in DNA microarray technology. Now researchers want to apply these benefits to boost the speed of proteomics research. But developing these tools is not easy, as protein arrays present technical challenges not faced by DNA microarray manufacturers. "You can attach any two pieces of DNA the same way and expect [them] to behave the

RNA interference (RNAi), discussed previously in The Scientist,1 is a post-transcriptional, targeted gene-silencing technique that uses double-stranded RNA (dsRNA) to degrade messenger RNA (mRNA) containing the same sequence as the dsRNA. The process occurs in at least two steps: an endogenous ribonuclease cleaves the longer dsRNA into shorter, 21- or 22-nucleotide-long RNAs, termed "small interfering RNAs" or siRNAs. The smaller RNA segments then mediate the degradation of the target mRNA.2 Rec

Most of the attention on gene expression analysis and discovery tools has centered on microarray technology, but alternative methods, including SAGE (serial analysis of gene expression)1 and direct cDNA sequencing, do exist. Another such technique is Hayward, Calif.-based Lynx Therapeutics' Massively Parallel Signature Sequencing (MPSS™) technology, a method for counting millions of mRNA molecules from a given sample. Like SAGE, MPSS quantifies tagged cDNA fragments; but whereas SAGE uses

LabVelocity.com, an online resource offering news, product information, and protocols to the life science community, is undergoing a transformation. As of Feb. 5, users can subscribe to ResearchLink, an enhanced version of the original site, and/or to Jellyfish, LabVelocity's popular sequence analysis software package; both were previously available free of charge. The San Francisco-based company is offering a 30-day free trial subscription to new and current users; the response to the trial per

Most reagents used for reducing disulfide bonds in peptides and proteins have unpleasant odors. To combat this problem, Pierce Chemical Co. of Rockford, Ill., has covalently attached the odorless reducing agent TCEP to an agarose support. Pierce's Immobilized TCEP Disulfide Reducing Gel allows reductions to be performed on the bench-top without the need for a fume hood and avoids the need for dialysis or gel filtration to remove the reducing reagent. Pierce Chemical Co. +1 (800) 874-3723 www.p

Santa Clara, Calif.-based Affymetrix's new GeneChip® Human Genome U133 set is the first commercially available microarray set designed using the April 2001 draft of the human genome. Affymetrix incorporated 2.7 million source sequences in the array's design; the final product includes 45,000 probes in a two-array set representing 39,000 transcripts from 33,000 well-substantiated genes. "Each of the arrays in the set has over 500,000 individual oligonucleotide features," says marketing direct

Researchers looking for highly sensitive RNA quantitation and the ability to multiplex often turn to the ribonuclease protection assay (RPA). In an RPA, the RNA sample is incubated with labeled RNA probes complementary to specific target sequences. After the target sequences and probes hybridize, the sample is treated with ribonuclease to degrade any unhybridized probe, and the "protected" probe/target hybrids are separated on a polyacrylamide gel, detected, and quantitated. Unlike Northern blo

Scientists working with recombinant proteins expressed in Escherichia coli probably use at least one liquid chromatography technique to purify their protein of interest. But liquid chromatography frequently requires a considerable amount of optimization, and usually involves several different chromatographic steps to rid the sample of contaminants.1 The ideal solution would be to create a resin that is completely specific to the target protein, enabling one-step purification. Affinity chromatogr

Until March 29, 2002, Stratagene of La Jolla, Calif., is offering a 30% discount on the 100-unit size of AccuType DNA polymerase. AccuType DNA polymerase is a high-fidelity PCR enzyme designed for genotyping and mutation detection applications using sensitive DHPLC technologies. The offer is valid for Stratagene direct customers only. Stratagene, +1 (800) 424-5444 www.stratagene.com Mass Spec Time Saver Millipore of Bedford, Mass., has introduced the Montage In-Gel Digest96 Kit for convenient

Leica Microsystems of Bannockburn, Ill., has introduced the ASP 300 Tissue Processor for histopathological sample processing. Unlike its predecessor, the TP 1050, the ASP 300 processor is a fully enclosed, fully automated, stand-alone system capable of processing up to 300 cassettes. The system features SMART operating software and an easy-to-use color touch screen. Users can create customized programs that are automatically launched with the touch of a button using the system's Smart-Start func

From individual academic laboratories to Big Pharma manufacturing plants, small- and large-scale protein purification usually requires some type of liquid chromatography. Most purification techniques have been in use for decades, but the development of new resins has improved the time-tested methods that exploit proteins' physical and chemical properties to effect separations. This profile examines four techniques—gel filtration (GF), ion exchange (IEX), hydroxyapatite (HAP), and hydrophob