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Archive - Dec 17, 2014

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New Coupling Technique May Have Immediate Applications in Pharmaceuticals, Materials, Agricultural, and Fragrance Chemistry

Chemists at The Scripps Research Institute (TSRI) in La Jolla, California, have invented a powerful method for joining complex organic molecules. This method is extraordinarily robust and can be used to make pharmaceuticals, fabrics, dyes, plastics, and other materials previously inaccessible to chemists. “We are rewriting the rules for how one thinks about the reactivity of basic organic building blocks, and in doing so we’re allowing chemists to venture where none has gone before,” said Dr. Phil S. Baran, the Darlene Shiley Chair in Chemistry at TSRI, whose laboratory reported the finding on functionalized olefin cross-coupling in an online article in Nature published on December 17, 2014. With the new technique, scientists can join two compounds known as olefins to create a new bond between their carbon-atom backbones. Carbon-to-carbon coupling methods are central to chemistry, but until now have been plagued by certain limitations: they often fail if either of the starting compounds contains small, reactive regions known as “functional groups” attached to their main structure. They also frequently don’t work well in the presence of “heteroatoms”—non-carbon atoms such as nitrogen, oxygen and iodine—despite the importance of these types of atoms in chemical synthesis. The new method is what chemists call “mild,” meaning that it doesn’t require the use of extreme temperatures or pressures, nor harsh chemicals. As a result, portions of the building blocks used that are particularly fragile remain unaltered by the reaction. “Functional groups that would be destroyed by other cross-coupling methods are totally unscathed when using our method,” said Julian C. Lo, a graduate student who was a co-lead author of the report with Research Associate Dr. Jinghan Gui.

Normally Solitary Desert Locust Transformed to Gregariousness by Activation of Specific Serotonin-Producing Nerve Cells

A team of biologists has identified a set of nerve cells in desert locusts that bring about ‘gang-like’ gregarious behavior when the insect are forced into a crowd. Dr. Swidbert Ott from the University of Leicester’s Department of Biology, working with Dr. Steve Rogers at the University of Sydney, Australia, has published a study, online on December 17, 2014 in an open-access article in The Royal Society Proceedings B, that reveals how newly identified nerve cells in locusts produce the neurochemical serotonin to initiate changes in their behavior and lifestyle. The findings demonstrate the importance of individual history for understanding how brain chemicals control behavior, which may apply more broadly to humans also. Locusts are normally shy, solitary animals that actively avoid the company of other locusts. But when they are forced into contact with other locusts, they undergo a radical change in behavior – they enter a “bolder” gregarious state in which they are attracted to the company of other locusts. This is the critical first step towards the formation of the notorious locust swarms. Dr. Ott said: “Locusts only have a small number of nerve cells that can synthesise serotonin. Now we have found that of these, a very select few respond specifically when a locust is first forced to be with other locusts. Within an hour, they produce more serotonin. It is these few cells that we think are responsible for the transformation of a loner into a gang member. In the long run, however, many of the other serotonin-cells also change, albeit towards making less serotonin.”