Articles by Deborah Wilkinson

Bio-Rad's PROTEAN® IEF System provides 2-D electrophoretic separation as part of the ProteomeWorks System Australian postdoctoral fellow Marc Wilkins coined the term "proteome" in the mid-'90s, referring to the total set of proteins expressed in a given cell at a given time. The term took hold, and a new scientific discipline was born. In proteomic studies, all the proteins from a given cell, organelle, or tissue are analyzed simultaneously with respect to properties such as expression leve

Capillaries Automated Capillary Electrophoresis Systems Agilent's CE-MS System Capillary electrophoresis (CE) is a fast-growing area of separation technology. CE techniques enable the high-resolution separation of an impressive variety of sample types, from ions and small molecules to macromolecules and from virus particles to whole cells. Online detectors speedily record sample component concentrations during these time efficient separations. "CE separations typically take 10-20 minutes," not

Antibody Purification Reagents The immune response is often exploited to produce those remarkably useful affinity reagents known as antibodies. Today's biological and biomedical laboratories employ an array of different immunochemical techniques. For example, a specific antibody can be harnessed to screen for the presence of its respective antigen, quantify the amount of antigen in a given sample, determine the antigen's subcellular location, isolate the antigen from complex mixtures, and sear

Tools for limited proteolysis studies X-ray crystallography and two-dimensional nuclear magnetic resonance (NMR) remain the methods of choice for determining the high-resolution three-dimensional structure of globular proteins. However, not every laboratory has the equipment and expertise required for these physicochemical methods. Before a protein can be examined by X-ray crystallography, it must first be crystallized. Some proteins form crystals more readily than others, and discovering the p

Expanded References   1. J.C. Kendrew et al., "A three-dimensional model of the myoglobin molecule obtained by x-ray analysis," Nature, 181:662-6, 1958; J.C. Kendrew et al., "Structure of myoglobin," Nature, 185:422-42, 1960. 2. C. Branden, J. Tooze, "Motifs of Protein Structure," Introduction to Protein Structure, Garland Publishing, Inc., New York, pp. 11-30, 1991; J.S. Richardson, "Describing patterns of protein tertiary structure," Methods in Enzymology, 115:341-8, 1985; J.S. Richardson

Chemiluminescent Western Blot Detection Kits Today's chemiluminescent detection methods give western blotters accustomed to using 125I a fast and sensitive alternative to thyroid bashing. Unlike detection systems based on fluorescence, chemiluminescent methods do not require external light sources for excitation energy. Rather, the signals are generated internally as light-producing chemical reactions occur. Chemiluminescent detection systems use reporter enzymes that catalyze luminescent react

The Invader assay technology is Third Wave Technologies' (Madison, Wis.) isothermal, "PCR-free" approach to the detection and quantitative analysis of DNA. Instead of amplifying the target of interest, and thereby increasing the chances of "carryover" contamination, the Invader assay produces and amplifies an unrelated signal only in the presence of the correct target sequence.1 These incredibly sensitive assays can be harnessed to quantify subattomole levels of target nucleic acids within compl

Automated Nucleic Acid Synthesizers Most of today's biological and biomedical laboratories simply could not function without ready access to user-specified oligonucleotides. Many researchers rely on core services or external vendors for their custom nucleotide needs. Other laboratories or departments choose to invest in oligonucleotide synthesizers for their exclusive use. Read on for a review of the basics of solid-phase oligonucleotide synthesis and a summary of some of the commercially availa

Date: September 13, 1999Table of Neurochemical Manufacturers The hypothalamus has long been known as a control center for feeding and weight control behaviors. Complex regulatory feedback loops enable this portion of the brain to determine satiety and metabolic activity. Not surprisingly, the control mechanisms are complex and involve different biochemical pathways.1,2,3 Image courtesy of Jeffrey M. Friedman An ob/ob mouse stacking up against its lean counterparts A series of pioneering expe

Do you routinely run DNA preps for PCR amplification? This is a common procedure in many laboratories. However, it is not always necessary to perform DNA preps prior to PCR. In many circumstances, all you need is lysis of the cells and release of the DNA. Microzone in the United Kingdom has recently introduced microLYSIS, a reagent designed to lyse a wide variety of different cell types prior to PCR. MicroLYSIS is a proprietary mixture of detergents formulated to lyse cells in less than 15 minut

Date: June 21, 1999Kits for In Vitro Translation and Transcription/Translation Systems Problem proteins--you know the ones. Some are rapidly degraded by endogenous proteins. Others are toxic to the very cells used to overexpress them. These types of problems can sometimes be avoided by using cell-free extracts for the in vitro expression of proteins. In vitro translation systems are also useful for other applications, including incorporating modified or unnatural amino acids for functional st

Indirect magnetic labeling for separation of murine cells. Image provided by StemCell Technologies Hematopoietic stem cells are defined by their ability to self-renew and to differentiate into all blood cell lineages. Human stem cell populations are frequently tested by their ability to populate the hematopoietic systems of immunodeficient strains. "The analysis of mice transplanted with human hematopoietic cells is essential to assess the hematopoietic long-term populating potential of the t

Tyrosine Phosphorylantion State-Sensitive Antibodies Protein tyrosine kinases (PTKs) are a diverse lot, including both transmembrane and soluble cytoplasmic enzymes. Roughly 10 percent of a cell's proteins are subject to covalent modification via phosphorylation, but tyrosine (Tyr) residues are modified in only about one out of every 100 protein phosphorylation events. When Tyr-phosphorylation occurs, cells pay heed. PTKs play vital roles in a wide variety of cellular processes, including gro

Chemiluminescent Gene Reporter Systems Features of Luminometers How is the expression of a given gene controlled? That is a question asked of many in the biological and medical sciences. "Reporter genes," which encode quantifiable enzymes or proteins, are often employed by researchers seeking to better understand how the expression of genes of interest is controlled. In these assays, the coding region of the gene under study is replaced with the sequence that encodes the reporter gene. Report

Fluorescence microscopy of calcein-labeled cells. The Influx™ cell-loading reagent was used to load RBL cells with calcein. The image was acquired using a fluorescence microscope equipped with a cooled CCD camera and a bandpass filter set appropriately for fluorescein. The micrograph was reprinted with permission from Molecular Probes, Inc. Do you need to "light up" your cells with a colorful tracer or study the effects of loading cells with a given macromolecule? Representatives at Mol