Imaging

Video-rate stimulated Raman scattering

Stimulated Raman scattering (SRS) microscopy is a label-free optical imaging technique based on the detection of signature molecular bond vibrations. Saar et al. now report technical developments that greatly increase the SRS imaging speed, allowing video-rate SRS microscopy. These advances facilitated SRS imaging of the skin and of small molecule drug penetration into the skin of living mice and humans, highlighting the potential utility of SRS for clinical imaging.

Saar, B.G. et al. Science 330, 1368–1370 (2010).

Genomics

It takes 1000 Genomes

The three pilot-phase projects of the international 1000 Genomes Project—whole-genome, high-throughput sequencing of two family trios, one of African and another of European ancestry, whole-genome sequencing at low coverage of 179 individuals from four populations, and exon sequencing in genomes of 697 individuals from seven populations—are now complete. The goal of the entire project is to decipher how genetic variation affects phenotype; the aim of the pilot phase was to compare sequencing strategies and catalog over 95% of commonly found variants in any individual.

The 1000 Genomes Project Consortium. Nature 467, 1061–1073 (2010).

Systems biology

Monitoring metabolite-protein interactions

The metabolome has received far less attention than the genome, the transcriptome and the proteome. Li et al. now present a large-scale, in vivo analysis of metabolite-protein interactions in yeast, demonstrating that metabolites may have more important regulatory roles than currently appreciated. Using an affinity purification–mass spectrometry approach, they found that 16 of 21 enzymes in the ergosterol biosynthesis pathway specifically associated with metabolites, as did 21 of 103 protein kinases.

Li, X. et al. Cell 143, 639–650 (2010).

Molecular biology

Robust minicircle DNA production

In contrast to standard plasmid vectors, minicircle DNA vectors (which lack the bacterial plasmid DNA backbone) allow more efficient and long-term transgene expression. Minicircle DNA vectors have not been widely used, however, because they are challenging to produce. Kay et al. now describe an approach to improve minicircle production to the level of plasmid DNA preparation, based on a modified Escherichia coli that stably expresses inducible minicircle assembly enzymes.

Kay, M.A. et al. Nat. Biotechnol. 28, 1287–1289 (2010).

Biophysics

A database for dynamics

Proteins are flexible molecules in constant motion; this motion is crucial for function. Experimental detection of the conformations that a protein samples is very challenging, but molecular dynamics simulations can help fill in some of the gaps. Meyer et al. present their molecular dynamics extended library (MoDEL) database, which contains native-state atomistic trajectories of more than 1,700 soluble proteins. The database is available at http://mmb.pcb.ub.es/MoDEL/.

Meyer, T. et al. Structure 18, 1399–1409 (2010).