Articles by Bob Sinclair

As genome sequencing becomes a regular occurrence, biology's attention can turn to the next logical step: proteomics. Fundamentally, proteomics is nothing less than the complete catalog of every protein in a given tissue, organ, or organism under a defined growth or disease state. Sometimes this definition is expanded to include protein-protein interactions. The data describe the types and quantities of proteins present and also indicate other proteins with which these molecules are complexed.

Medical miracles abound, yet cancer continues to be a complex and challenging problem. "Cancer" is actually a generic, catchall term for the malignant tumors that are found in well over a hundred different diseases, but the basic concept is simple enough--a gene goes wrong and a tumor grows. Unfortunately, the reality is more complicated, involving an intricate sequence of phenomena and interactions in just a handful of the body's tens-of-trillions of cells. And therein lies the problem for rese

Stratagene's Vitality™ hrGFP (green fluorescent protein) mammalian expression vectors allow protein expression and subcellular localization studies similar to those using jellyfish (Aequorea victoria) GFP, with one important difference: Stratagene's hrGFP exhibits less toxicity in many mammalian cells. Renilla reniformis, an Anthazoan sea pansy related to the jellyfish, produces a 238 amino-acid protein that has broader pH stability, more resistance to solvents, detergents, and proteases,

Not so long ago, researchers had somewhat limited choices for locating and following a particular piece of DNA. A probe could be labeled using radioactivity, by kinasing an end or nick-translating the whole piece. A fragment of interest could be visualized (along with all other DNA and RNA species in the preparation) using ethidium bromide. With sufficient skill and patience an investigator could obtain from these rather crude techniques fairly impressive information, such as the precise 5' end

D3 embryonic stem cells cultured in Life Technologies' KNOCKOUT D-MEM Just last year Science hailed stem cell isolation and culture as the "breakthrough of the year."1 Much of the excitement over stem cells derives from their potential to differentiate into any cell type in the body. A fertilized egg, for example, is a single cell that is capable of eventually creating all the different cells that make up the mature organism. As such, a fertilized egg and the daughter cells of the first few divi

Early attempts to design vehicles for the cloning of foreign DNA produced vectors that were too big, unstable, or unselectable. The tide turned in 1977 with the construction of pBR313, the direct ancestor of the well-known pBR322, which forms the basis of many vectors that are still used extensively today.1 However, the cloning systems introduced in the last year or so seem to be about as related to pBR313 as Ferraris are to little red Radio Flyer wagons. Some of the new protein expression syst

Photo: Amy FrancisTerry Weber, research technician at the Children's Hospital of Philadelphia, uses radioisotopes to label probes for chromosomal mapping studies. Edwin M. Southern's 1975 paper, "Detection of specific sequences among DNA fragments separated by gel electrophoresis," described one of the landmark advances in early molecular biology. A new era was dawning as it suddenly became possible to detect specific sequences among the thousands of fragments produced by a restriction digest

IGEN's ORIGEN Analyzer For diagnostics, drug discovery, and basic research, nothing beats the right assay. IGEN International of Gaithersburg, Md., has developed a new electrochemiluminescence (ECL) detection process, termed ORIGEN Technology, that can be applied to many different types of binding assays. IGEN's M-SERIES Analyzer uses ECL to speed immunoassays, quantitation of nucleic acids, receptor-ligand binding assays, and measurement of viruses and bacteria. IGEN's ORIGEN Technology

Nucleic Acid Dyes and Stains DNA molecular weight markers stained with Molecular Probes' SYBR Green I Researchers working with DNA often have two fundamental questions: "How much DNA have I got?" and "What size is it?" Large quantities of DNA can be visualized even without staining or special illumination: The schlieren lines--refractive index changes at the boundaries of concentration differences--reveal the positions of the bands. However, this method is impractical for most applications. For

Tools for Cytokine Research Companies producing cytokines Courtesy of Alexis CorpCytokine Network Many proteins and peptides affect the growth, identity, and function of eukaryotic cells. Very often their effects are highly pleiotropic, making exact boundaries and distinctions between proteins such as hormones, growth factors, and cytokines difficult to pin down. The result is a nomenclature tangle almost as complex as the regulatory circuits these molecules mediate. Although this treatment of

Lab-on-a-Chip For microfluidics, tiny sample volumes move through microchannels etched into a glass chip. Some may argue that the September 1999 release of the Agilent 2100 Bioanalyzer was premature--the technology clearly belongs in the new millennium. With this instrument, Agilent Technologies of Palo Alto, Calif., a Hewlett-Packard subsidiary, in collaboration with Caliper Technologies Corp., of Mountain View, Calif., has achieved the first commercial realization of lab-on-a-chip technology.

Grow 'n' Glow GFP Two Hybrid System Many genetic and cellular processes rely on highly specific protein-protein interactions. Two-hybrid systems provide a way to systematically identify pairs of proteins (referred to as "bait" and "prey" proteins) that form stable contacts, and further, to identify which protein segments or domains are necessary to form the complex. MoBiTec's Grow 'n' Glow GFP Two-Hybrid System combines a relatively straightforward two-hybrid strategy with inducible expression,

Most researchers would agree that manually performing a hundred or so plasmid preps after a low-efficiency cloning stifles the spirit of exploration that attracted them to science. Minipreps don't end with merely being tedious, repetitive, and time consuming--frequent exposure to hazardous chemicals adds to the misery. However, minipreps are a necessary evil in research, and the number of sequencing templates to prepare never seems to dwindle. For example, a small lab running four sequencing gel

Micromanipulator Tables In the early 1970s, researchers showed that macromolecules retained activity when injected into living cells. Since then, studies involving the activity or fate of any number of natural and synthetic macromolecules as well as transplanted organelles have created an informative field. Injected material can be studied directly, or longer-term effects such as transformation can be monitored; with some materials it is even possible to reisolate and characterize the injected m

MALDI-TOF Table Micromass' laser-addressable sample array target for MALDI Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry has become, in recent years, a tool of choice for large-molecule analyses, especially for proteins. Published applications address protein and nucleic acid sequence, structure, purity, heterogeneity, cleavage, posttranslational modification, and a host of other molecular characteristics that are often difficult to study