ChemWeb Newsletter

Not a subscriber? Join now.May 17, 2005


In this issue, The Alchemist shines his torchlight on X-ray studies of magnetic materials, reads a guidebook for spotting extraterrestrial microbes, finds out how to defeat drug resistance, learns that an environmental spike is no problem for the pike, and finally uncovers the truth behind Biblical pigments.

Scientists at the Universities of Sheffield and Warwick, UK, working with the European Synchrotron Radiation Facility, have used X-rays to investigate magnetic structures with unprecedented detail at the atomic scale. The technique is 100 times more sensitive than previously used methods, and has offered the researchers a glimpse of how changes in magnetic materials affect structure and properties. The team says their approach could have applications in improving data storage, developing medical sensors, and in security systems. Team leader Mike Gibbs adds, "This new technique uses X-rays to look at the movement of atoms with unprecedented resolution. Once we can look at atom positions in this way, we will get a much better idea about the atomic structures of a range of materials, meaning that we will be able refine our understanding of how structures and materials are made up."

A new chemical guidebook and spectral imaging system developed by scientists at the US Department of Energy's Idaho National Laboratory and the Universities of Idaho and Montana will allow a future Martian rover to spot the signs of life on the red planet. The chemical guidebook based on mass spectrometric data will carry profiles of earthbound rocks and other materials that have been exposed to microbial life as well as data from control samples. A Martian rover thus armed could autonomously seek out the signs of life.

The crystal structure of the membrane transporter protein, MsbA, which is key to the emergence of drug resistance in bacteria and cancer cells alike has been determined by Scientists at The Scripps Research Institute. The discovery could lead to a new design approach to anticancer and antibiotic drugs that precludes resistance. "We actually have very good drugs to fight cancer and to kill bacteria," explains team leader Geoffrey Chang "But they can't always get in the cells to work." Bacteria use MsbA proteins to block antibiotics while the equivalent proteins in human cancer cells similarly undermine chemotherapy agents. Details gleaned from the crystal structure could allow researchers to circumvent these cellular defenses.

Contrary to popular opinion, estrogenic compounds in the environment may not be "biomagnified" along the foodchain to the point where they pose a serious threat to fish at the top of the food chain, according to UK researchers who have studied biomagnification of estrogen on the predatory pike fish. According to researchers writing in the journal Environmental Toxicology and Chemistry, ethinylestradiol, a contraceptive and hormone replacement compound, appears at its most toxic concentrations downstream of major sewage treatment works. The researchers tested pike upstream and downstream of a sewage works and found that although 14% of the fish were "intersexed" the incidence of masculinization was independent of whether the pike had been sampled upstream or downstream. The study's results show that estrogen may not biomagnify in food chains, and the potentially adverse effects of this endocrine modifier may not be as pervasive as had been feared.

The Gutenberg Bibles were the first books printed using moveable type but are just as famous for their colorful illustrations. Now, UK researchers have used a non-invasive spectroscopic technique to identify the precise pigments used in the Gutenberg illustrations. The findings not only provide chemical data that might help conservationists, but could also provide new insights into the printing practices of fifteenth century Europe. "This represents an important first step in an appropriate conservation and preservation strategy," says study co-author Gregory Smith, formerly of University College London and now a professor of conservation science at Buffalo State College in New York. Raman spectroscopy has now revealed, for the first time, the exact chemical composition of the bright red color: cinnabar or its synthetic equivalent vermilion; the yellow is lead tin yellow (lead stannate); black is carbon; blue is azurite, (copper carbonate); white is calcium carbonate; olive green is malachite (another copper carbonate); and dark green is verdigris (copper ethanoate).