Volume 6 Issue 2, February 2009

Methods to map active RNA polymerases and to assign transcripts to the sense or antisense strand are valuable additions to the functional analysis of the transcriptome.

A new system capable of simultaneously monitoring thousands of individual polymerase enzymes enables accurate, multiplex DNA sequencing in real time.

By analyzing the data generated by the Northeast Structural Genomics Consortium (NESG), researchers quantified the physical properties that control protein crystallization.

Researchers develop a high-sensitivity, label-free imaging technology based on stimulated Raman scattering.

Using time-lapse imaging, researchers study the potency and fate specification of live neural stem cells in culture.

Kinetically bi-stable channelrhodopsin-2 variants enable sensitive, step-like and reversible photoexcitability in neurons.

A microfluidic device enhances the efficiency of cell membrane fusion by increasing the efficiency of cell pairing.

Two groups present new photoactivatable fluorescent proteins that will be useful for super-resolution fluorescence microscopy.

Pseudorabies viruses encoding fluorescent proteins are a powerful method for mapping neuronal circuits. Now a series of pseudorabies virus strains encoding fluorescent sensors and time-shifted florescent proteins allow dissection of complex circuits with concurrent activity analysis while defining an analysis period during which the neurons are still healthy.

An improved version of the green-to-red photoconverting EosPF is presented. mEos2 is a functional fusion partner for many cellular proteins and retains the high localization precision of EosFP in super-resolution imaging. Also in this issue, Subach et al. present an inducible mCherry variant for super-resolution imaging.

S-palmitoylation is a protein post-translational modification involved in trafficking, compartmentalization and membrane-tethering of various proteins. A palmitic acid analog, 17-octadecynoic acid, serves as a metabolically incorporated bioorthogonal click chemistry probe for detecting S-palmitoylated human proteins by mass spectrometry or in-gel fluorescence.

Conventional in situ hybridization protocols lead to loss of microRNAs, which diffuse out of the formaldehyde-fixed sample owing to their small size. Adding a carbodiimide that stably links the microRNA with the protein matrix around it prevents this diffusion and allows detection of miRNAs at very low expression levels.

A combination of multiphoton laser scanning microscopy and second harmonic generation (SHG) imaging is used to track tumor associated fibroblasts and extracellular matrix remodeling in living mice. The SHG signal is used for image registration over several days.

A device that traps cells in micrometer-sized capture cups efficiently achieves cell pairing and subsequent chemically or electrically induced fusion. The authors show that fused NIH 3T3 cells continue to be viable and morphologically normal off the chip, and they also show reprogramming of mouse embryonic fibroblasts after fusion with embryonic stem cells.

Improved photoactivatable red fluorescent proteins are generated by including properties desirable for photoactivated localization microscopy (PALM) as selection criteria. The PAmCherry proteins are superior tags for one- and two-color PALM in fixed cells, among other applications. Also in this issue, McKinney et al. present an improved version of the green-to-red EosFP protein.

A ratiometric fluorescent sensor that reports the ATP/ADP concentration ratio in living cells was created by fusing the bacterial regulatory protein GlnK1 to a circularly permuted fluorescent protein. The sensor detected inhibition of cellular metabolism caused by transient removal of glucose from the cellular medium or administration of a glycolytic inhibitor.

A piezo-resistive dual-cantilever system is combined with fluorescence imaging to examine the mechanical features of the in vitro–assembled vertebrate meiotic spindle.

Biobanking is gaining momentum as more and more patient samples and clinical information are being stored in facilities around the globe. New technology is helping everyone—from national efforts to smaller research laboratories—to process and track their biospecimen collections.