Articles by Hillary Sussman

SELECTION STRATEGY:Courtesy of David McNeillThe genetically altered bacteria on this plate are easily detected under ultraviolet light. Escherichia coli were transformed with a plas-mid encoding the green fluorescent protein (GFP), which makes the colonies fluoresce under UV light. The transforming plasmid also encodes resistance to the antibiotic ampicillin, which allows the cells to grow on this antibiotic-containing agar dish. But in this image, the ampicillin resistance is leaking out of the

Microarray manufacturer Affymetrix of Santa Clara, Calif., http://www.affymetrix.com and laser-capture microdissection company Arcturus of Mountain View, Calif. http://www.arctur.com, have teamed up, offering the GeneChip X3P array and the Paradise™ reagent system, respectively, to enable gene expression analysis of archived formalin-fixed, paraffin-embedded (FFPE) samples. "These samples represent a treasure trove for genomic discovery efforts, because they generally are associated with k

Courtesy of GenetixStandard mammalian tissue culture techniques usually require growth media refreshment every two to three days, accomplished by manually pouring or pipetting off the old medium and replacing it with new. To circumvent this tedious process, New Milton, UK-based Genetix http://www.genetix.co.uk recently launched QFresh, the first instrument designed for the automatic exchange of culture media in petri dishes.The programmable instrument does it all: A mechanical apparatus removes

Courtesy of Mirjam Lohmann Microarray processing often takes place in core facilities and includes multiple instruments: a hybridization chamber, a fluidics station, a scanner, and a spotter for printing customized arrays. Now scientists can perform genotyping, gene expression profiling, and resequencing experiments at their own lab benches. The geniom® one from Mannheim, Germany-based febit, recently launched in Europe and slated for US release in 2004, is a fully automated benchtop micr

Courtesy of Invitrogen Protein kinases play a pivotal role in the signal transduction pathways that regulate cellular metabolism, growth, proliferation, differentiation, and death. By catalyzing the transfer of phosphate groups from ATP to specific serine, threonine, or tyrosine residues on other proteins, protein kinases modulate those proteins' activity, ultimately inducing changes in gene expression. Deregulation of these events can lead to pathology (Alzheimer disease, diabetes, or cancer,

Courtesy of Amersham Biosciences Whole-genome amplification (WGA) can replenish dwindling stocks of genomic DNA or bolster low yields, which limit the number of downstream assays that can be completed. PCR-based WGA methods can introduce amplification bias and generate products of insufficient length for some applications, such as RFLP analysis. To alleviate this problem, Amersham Biosciences of Piscataway, NJ, released in April the GenomiPhi™ DNA Amplification Kit, a non-PCR-based meth

Courtesy of Ivan Rayment  CAUGHT IN MID HOP: Structure of the Tn5 transposase/DNA complex No one believed Barbara McClintock in 1951 when she first described DNA that "jumped" from site to site within maize chromosomes, altering the expression of genes near the sites of integration. In due course, these transposable elements, or transposons, were found to be ubiquitous in nature, and 30 years later McClintock won the Nobel Prize. Today transposons have gone from molecular oddity to molec

Nucleic acid purification procedures have enjoyed a long history, beginning with the first isolation of "nuclein" in 1869 by Freidrich Meischer. In 1958, Matthew Meselson and Frank Stahl demonstrated semiconservative replication of DNA using density-gradient centrifugation, an isolation method that became the cornerstone of recombinant DNA technology in the '70s and '80s. The technology was effective--producing high-quality DNA--but it was not efficient. The classical method of isolating pla

Studying changes in cytokine expression may help scientists understand the roles of these proteins in human health and disease, and lead to advances in the diagnosis and treatment of inflammatory diseases, cancer, and AIDS. Researchers commonly quantify cytokines in biological samples with immunoassays, using matched antibody pairs for cytokine detection. Keene, NH-based Schleicher & Schuell BioScience (S&S) now offers an alternative approach with its ProVision™ Human Cytokine A

Volume 16 | Issue 13 | 37 | Jun. 24, 2002 Previous | Next QIAGEN Reveals a Sensitive Side Highly sensitive microarrays provide a true expression profile | By Hillary E. Sussman Photo: Courtesy of Qiagen SensiChip DNA microarray bar Since their inception, DNA microarrays have been valuable in fields ranging from drug discovery to agricultural engineering. But the high-density chips suited

Manchester, UK-based Micromass has added negative-ion detection capabilities to its M@LDI™ family of mass spectrometers. The company unveiled this new feature in New Orleans at Pittcon 2002, an annual trade fair where more than 30,000 conferees and exhibitors in virtually every laboratory discipline launch new products. To perform matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS), researchers combine the sample with a molar excess of matrix̵

RNA transfection for direct functional analysis of RNA species is becoming increasingly popular. This is due, in part, to exploding interest in RNA interference (RNAi), a gene-silencing technique used in studying fruit flies, nematodes, and mammalian cells that relies on the introduction of short RNA duplexes into the cell.1 Like antisense RNA, scientists use RNAi to determine gene function by blocking the expression of a specific mRNA. Researchers can transfect other types of RNA molecules as w

Suppliers of Reporter Assay Screening Systems Courtesy of Applied BiosystemsTarget practice: Researchers can employ reporter assays to study a variety of cellular processes. Rarely is the product of a gene readily distinguishable from the myriad mRNA and protein complements that exist in a cell at any point in time. But researchers can skirt this obstacle by placing a "reporter gene" under the same controls as the gene of interest. Reporter genes have easily measurable phenotypes that form th

The Scientist 15[15]:25, Jul. 23, 2001 PROFILE Suppliers of Reporter Assay Screening Systems  E-mailarticle Company Product Reporter Gene Reporter Chemistry No. Tests* Price Amersham Pharmacia Biotech (800) 526-3593 www.apbiotech.com Quan-T-CAT [3H] Assay System CAT [3H]-acetylated, biotinylated chloramphenicol 100 $450 Applied Biosystems (800) 345-5224 www.appliedbiosystems.com Gal-Screen Reporter Gene Assay for Mam

Microarrays, or "gene chips," have become valuable tools for studying changes in gene expression; detecting genetic mutations and polymorphisms; analyzing drug resistance and disease susceptibility; and sequencing unknown DNA. The microarray, which consists of cloned genes, PCR products, or synthetic oligonucleotides immobilized on a microscope slide, is analyzed by hybridization with target DNA or RNA that is labeled with radioisotopes or fluorescent dyes.1 For example, total mRNA isolated from