Imaging and Visualization

Synthesis of water-dispersible, fluorescent, radio-opaque and paramagnetic CdS:Mn/ZnS quantum dots: a multifunctional probe for bioimaging

Santra et al. introduce a new class of stable, in vivo–friendly quantum dots (QDs), which, besides generating stable fluorescence, are also radio-opaque and paramagnetic, enabling detection by a variety of scanning methodologies and thus opening up new possibilities for noninvasive bioimaging.

Santra, S. et al. J. Am. Chem. Soc., published online 21 January 2005.

DNA Cloning and Amplification

MAGIC, an in vivo genetic method for the rapid construction of recombinant DNA molecules

The mating-assisted genetically integrated cloning (MAGIC) system combines bacterial mating, in vivo site-specific endonuclease cleavage and homologous recombination to effect the transfer of DNA fragments between a donor vector in one bacterial strain and a recipient vector in a different strain, simplifying the construction of recombinant DNA libraries.

Li, M.Z. & Elledge, S.J. Nat. Genet., published online 30 January 2005.

Cheminformatics

Metabolizing enzyme toxicology assay chip (MetaChip) for high-throughput microscale toxicity analyses

There is a need for in vitro assays that can identify toxic effects resulting from metabolic processing of drugs. Lee et al. introduce the MetaChip, a high-throughput system for such assays. An array of sol-gel–encapsulated cytochrome P450 enzymes is exposed to compounds of interest, and then is apposed against a monolayer of cultured cells, allowing direct assessment of toxicity.

Lee, M.-Y. et al. Proc. Natl. Acad. Sci. USA 102, 983–987 (2005).

Microarrays

Biosynthetic labeling of RNA with uracil phosphoribos-yltransferase allows cell-specific microarray analysis of mRNA synthesis and decay

Cleary et al. introduce a microarray strategy designed to directly monitor changes in the production and degradation of mRNA over a set period of time. By tracking incorporation of a tagged uracil analog in newly synthesized transcripts, one can determine the extent to which shifts in mRNA abundance result from changes in rate of synthesis or transcript turnover.

Cleary, M.D. et al. Nat. Biotechnol., published online 30 January 2005.

Virology

Human immunodeficiency virus type 1 vectors with alphavirus envelope glycoproteins produced from stable packaging cells

The Env glycoprotein is an essential determinant of host range for the human immunodeficiency virus (HIV); by incorporating Env variants, one can generate HIV-derived vectors capable of targeting both human and animal cells. Strang et al. have applied a stable HIV-1 packaging system, STAR, to generate alphavirus-pseudotyped HIV particles with considerably broadened tropism.

Strang, B.L. et al. J. Virol. 79, 1765–1771 (2005).