ChemWeb Newsletter

Not a subscriber? Join now.September 28, 2004


The Alchemist Newsletter is back from a well deserved vacation and a move from London to Los Angeles. Now published by, the newsletter and the ChemWeb site will continue to be offered as free services. We are working on some exciting new features for both and ChemWeb, and will notify our users by email in the weeks to come. Please contact the with your comments and suggestions.

This issue, we report on five more hot topics in chemistry. First, we reveal how landmark sugar biochemistry was recognized by the American Chemical Society and discuss how a 22nd genetically coded amino acid is found to be fully functional in E. coli. We also learn that, despite the received wisdom, chemistry can affect nuclear properties and could provide a new approach to medical tracers and how a radio signal from outerspace hints at a sugary origin to life on earth. Finally, don't hold your breath, but research into the active ingredient in cannabis could be the key to stopping cancer-causing herpes in its tracks.

The American Chemical Society named pioneering carbohydrate research by Carl and Gerty Cori a National Historic Chemical Landmark on September 21. During the 1920s, the Coris worked at Washington University in St. Louis and conducted a series of pioneering studies that led to our current understanding of how sugars are metabolized and the role this plays in diabetes. The pair won the Nobel in Physiology or Medicine in 1947 for the development of what became known as the "Cori cycle." In this process the body converts glucose into glycogen for storage. The Coris isolated and purified many of the enzymes involved in glucose metabolism, and their work ultimately advanced scientific understanding of metabolic regulation. The American Chemical Society established the chemical landmarks program in 1992 to recognize seminal events in the history of chemistry and to increase public awareness of the contributions of chemistry to society.

A 22nd natural genetically coded amino acid was discovered by US researchers two years ago. Now, they have taken the next logical step in amino acid chemistry and successfully synthesized the compound, L-pyrrolysine, and demonstrated that the microbe Escherichia coli can incorporate it into its proteins. Scientists assumed until 1986 that there were only 20 "canonical" amino acids, but the discovery of selenocysteine changed the received wisdom. Then in 2002, microbiologist Joe Krzycki and biochemist Michael Chan of Ohio State University added a 22nd amino acid to the list. Krzycki suggests that future work may lead to artificial proteins with unusual chemical properties for use in medicine or industry.

Irrespective of scientific received wisdom, the chemical environment of an atom can nevertheless affect its nuclear properties. According to researchers writing in Physical Review Letters, the half-life of a beryllium-7 atom trapped inside a fullerene C60 molecules (referred to as endohedral beryllium, Be@C60) changes by 1%. The researchers at Tohoku University and Yokohama National University in Japan suggest that the enclosed environment in which the beryllium atom finds itself affects one of the natural decay processes of this element. The unstable beryllium-7 nucleus can usually capture one its own electrons resulting in a proton turning into a neutron. However, within the cage-like environment of the C60, the rate of electron trapping rises slightly leading to the shift in decay rate. The team suggests that the discovery might lead to specialized radiotherapy carriers and tracers.

A frigid reservoir of simple sugar molecules has been discovered in a cloud of gas and dust 26,000 light years from earth close to the center of the Milky Way Galaxy. The discovery suggests how the molecular building blocks necessary for the creation of life may have first formed in interstellar space. Glycolaldehyde was observed with the National Science Foundation's giant Robert C. Byrd Green Bank Telescope (GBT) a radio telescope that can spot the chemical fingerprints of organic molecules in the interstellar medium that exist at just 8 kelvin. The study shows that pre-biotic molecules such as the 2-carbon sugar glycoaldehyde, which can be converted to the 5-carbon sugar ribose, are available to planetary systems and could have reached earth in the distant past putatively seeding life on our planet.

Inactivated derivatives of delta-9 tetrahydrocannabinol (THC), the primary psychoactive compound in cannabis, could find use in treating a form of herpes that can cause cancer. Researchers at the University of South Florida College of Medicine have shown that, in the laboratory at least, THC inhibits the replication of the gamma herpes virus. The team explains that THC specifically targets viral and/or cellular mechanisms shared by gamma herpes viruses and used in viral replication. The findings point to a possible new approach to treating herpes.

Not a subscriber? Join now.September 13, 2004


The Alchemist Newsletter is back from a well deserved vacation and a move from London to Los Angeles. Now published by ChemIndustry, the newsletter and the ChemWeb site will continue to be offered as free services. We are working on some exciting new features for both ChemIndustry and ChemWeb and will notify our users by email in the weeks to come. Please contact the with your comments and suggestions.

In this, the third issue of the all-new Alchemist, David Bradley discovers how tiny zinc oxide needles can capture whispers of light, and how feeding an antioxidant to plants could turn them into robust metal miners. Also in this issue, we learn about the toxic flame retardants coming straight off the supermarket shelves, and how NMR spectroscopy is revealing the hidden signal in catalytic hydroformylation. Finally, a molecular rotor brought back childhood memories of a toy gyroscope and pointed to the future of components for molecular scale machines.

A microscopic "whispering gallery" for light has been created by saturating molten gold with a zinc oxide plasma to create an array of tiny spires. The material carries light of different wavelengths like a whispering gallery carries sound. Visitors to the rotunda in London's St. Paul's Cathedral can hear each other's whispered conversations from one end of the gallery to the other because of the way the walls curve. Now, Marius Grundmann of the University of Leipzig in Germany and his team have fabricated and analyzed a tiny whispering gallery that has a similar effect to the rotunda but with visible light rather than sound waves. The nano-gallery is built from tiny needles of zinc oxide with a hexagonal cross section that are each just 800 nanometers long. The researchers suggest that their needles will help researchers understand the behavior of light at nanoscales, an important step in creating nanolasers for quantum data transfer, microscopy, and lithography.

The antioxidant glutathione can help certain plants to thrive on soils containing enough metal ions to kill most other plants according to researchers at Purdue University writing in the September issue of research journal The Plant Cell. The work of David Salt and John Freeman could provide a new approach to using plants in the bioremediation of metal-contaminated sites, such as old industrial sites and other brownfield areas. "We were able to clearly establish for the first time that plants that create and accumulate high cellular levels of glutathione are much more nickel tolerant," explains Salt. The finding could be useful to researchers hoping to use plants in phytoremediation for clean-up or in "phytomining" to extract useful metals from the soil.

A mechanistic study of one of the most important industrial reactions, hydroformylation, is providing new understanding of the process. The UK team carrying out the work has used an NMR approach to detect products through signals that are 30,000 times stronger than usual. To help them work out the details of how metal catalysts work in detail. According to Simon Duckett and colleagues at the University of York and researchers at Sasol Ltd in St Andrews, Scotland, "The rewards of achieving a greater understanding of such mechanisms are dramatic, leading to significant improvements in atom efficiency and hence fulfilling the chemist's desire to make a positive contribution to today's greener world".

Flame retardant chemicals, PBDEs (polybrominated diphenyl ethers), have been found in foods taken straight from supermarket shelves in Dallas, Texas, according to a research paper published this month in the journal Environmental Science & Technology. PBDEs were recently reported in the milk of nursing mothers in the USA, such halogenated compounds resemble polychlorinated biphenyls (PCBs) in terms of their chemical and toxicological profiles. The latest findings suggest that food may be a key source of the contamination measured in people around the world.

Takanori Shima and John Gladysz of the University of Erlangen-Nuremberg have designed and built the first fully enclosed molecular rotor system, which resembles a gyroscope. The structure, confirmed by crystallographer colleague Frank Hampel, consists of an iron tricarbonyl core surrounded by a framework of three methylene chains whose length can be varied. The iron tricarbonyl core functions as the rotating disk and center of the gyroscope, say the researchers, with the methylene chains acting as the spokes. Such materials emulate nicely the function of macroscale objects such as the real gyroscopes and could one day become essential components in supramolecular machines.