Chemical Science Blog

Cell membranes are made up of a mixture of different lipids and proteins. Membrane lipids aren’t randomly distributed but instead form raft-like microdomains. These are thought to provide platforms for protein interaction allowing protein trafficking and cell signalling.

Scientists have found it difficult to study these microdomains because their reported size is smaller than the resolution of light microscopy. Now a team of scientists from Japan and Belgium have circumvented this limitation by designing probes for cholesterol and sphingolipid-enriched microdomains for use in superresolution microscopy.

They visualised clustering of lipid molecules in nanodomains with a spatial resolution one order of magnitude better than the diffraction limit and were able to resolve the detailed structure of the domains.

Read more:
Fluorescent probes for superresolution imaging of lipid domains on the plasma membrane
Hideaki Mizuno, Mitsuhiro Abe, Peter Dedecker, Asami Makino, Susana Rocha, Yoshiko Ohno-Iwashita, Johan Hofkens, Toshihide Kobayashi and Atsushi Miyawaki, Chem. Sci., 2011, DOI: 10.1039/C1SC00169H

Johan Hofkens, one of the authors of this manuscript, is a plenary speaker at the forthcoming Challenges in Chemical Biology (ISACS5) meeting. Register by 24th June to hear him speak.

A team of scientist from the US and India have developed a simple and sensitive way to detect ricin in liquid foods, such as orange juice and milk.

Ricin is a protein toxin naturally present in the castor bean plant (Ricinus communis); it is classified as a ‘select’ bioterror agent and was involved in a recent bioterrorism attack plot targeting US hotels and restaurants at multiple locations, as reported by the Department of Homeland Security officials in December 2010.

 Theodore Labuza, at the University of Minnesota, and colleagues developed a two-step assay, in which the ricin was first captured out of food matrices by aptamer-conjugated silver dendrites and then the Raman spectrum was directly read on the silver dendrites. The measurement is based on the Raman ‘‘finger-print’’ of the target itself. Combined with the specific capture agent, Labuza says false positive results are extremely unlikely.

The assay shows great promise as a rapid (<40min), sensitive, and simple ‘‘Yes/No’’ method to detect bio-weapons, say the researchers.

Find out more for free by downloading Labuza’s Chemical Science Edge article.

Also of interest
ChemComm Surface Enhanced Raman Spectroscopy web themed issue

A racemic Au(I)-catalysed three-component reaction has been developed by US scientists to prepare cyclic carbamimidates from imines, terminal alkynes and sulfonylisocyanates. This reaction exploits the carbophilic π-acidity of gold catalysts to first activate an alkyne toward deprotonation and then to activate the internal alkyne generated toward intramolecular O-cyclisation.

Unlike similar previously reported multicomponent gold-catalysed reactions, the stereocentre generated during the alkynylation is preserved in the product. This trait was exploited by developing an enantioselective variant, using an unusual trans-1-diphenylphosphino-2-arylsulfamidocyclohexane ligand.

Moderate to excellent levels of enantioselectivity were obtained using a variety of N-arylbenzylidene anilines.

Find out more:
M J Campbell and F D Toste, Chem. Sci., 2011, DOI: 10.1039/c1sc00160d