Bees tell life story with perfumes
German chemists have discovered that bees recycle lipids in order to build up a unique bouquet of smells during the course of their lives.
Male orchid bees spend much of their lives collecting volatile compounds - usually terpenoids - from various strongly-scented sources, including flowers, leaves, rotting fruit and faeces. The bees store the fragrances in pockets on their back legs, by dissolving them in lipids that they secrete from a gland inside their heads.
Thomas Eltz and colleagues from the University of Dusseldorf showed that bees selectively reabsorb and reuse the lipids, rather than continually synthesising new compounds - a very economic way of collecting fragrances. The researchers found that synthetic deuterated versions of bee lipids, smeared onto the sponge-like leg pockets of the insects, disappeared completely after three days, and reappeared in the bees’ heads.
The fragrances are released during courtship and territorial behaviour. ’We think the scent attracts females but that hasn’t been shown,’ said Eltz. The research is published in the Proceedings of the Royal Society B(DOI:10.1098/rspb.2007.0727).
Three of the main classes of bactericidal drugs, despite hitting very different primary targets, all trigger the same mechanism that leads to cell death, US researchers reported in Cell (DOI: 10.1016/j.cell.2007.06.049). Whether each drug primarily targeted bacterial DNA, proteins, or cell wall, they all also induced the formation of hydroxyl radicals, reactive species which help to kill off bacteria.
The Boston University team suggested that, by blocking the bacterial repair response to free radical damage, all bactericidal antibiotics could be made more effective.
Bacteriostatic drugs, which work by inhibiting bacteria growth rather than killing cells, don’t share the same hydroxyl radical effect.
The standard textbook account of the chemical revolution has 18th century French chemist Antoine Lavoisier winning over the entire chemical community almost overnight, with the appearance of oxygen quickly consigning phlogiston (a hypothesised fire-like element released during combustion) to the intellectual scrapheap.
But new research from Hasok Chang, of University College London, shows plenty of high-profile dissenters hung on to the phlogiston hypothesis for decades. A well-conducted national campaign contributed to the later glorification of the immediacy of Lavoisier’s impact, Chang suggested in a paper delivered to the annual meeting of the British Society for the History of Science.
Chang considers that Lavoisier’s greater contribution lay in his attention to details such as balancing weight in his reactions, which helped the transition from a chemical universe ruled by immutable phlogiston-like ’principles’ to one comprised of simple, lego-like building blocks.
EPA defends industry funding
The US Environmental Protection Agency is defending its growing practice of jointly funding research with industry, after lobby groups voiced concerns that the agency’s science was being compromised.
Over half the EPA’s 70 active cooperative research and development agreements (CRADAs) are now with industry - dwarfing the number it holds with universities or local governments. Detractors questioned whether the CRADAs are an effective use of funds; to some it appears that industry is increasingly setting the scientific agenda at the agency at a time when the EPA’s public research funding is dwindling. Jeff Ruch, executive director for US lobby group Public Employees for Environmental Responsibility, told Chemistry World, ’The concern is capture of the regulatory agency by the regulated.’
But agency officials said joint ventures with industry allow the EPA to access valuable resources and bring more money into the agency for science. The research carried out under the agreements, which includes chemicals safety testing and new vehicle transmission systems, will lead to better protection of human health and the environment, officials said.
Grapevine genome cracked
The genome of the grapevine, Vitis vinifera, has been decoded by French and Italian scientists.
The team, publishing in Nature (DOI: 10.1038/nature06148), chose a grapevine variant derived from Pinot Noir cultivates. First analyses found that stilbene synthase enzymes (STSs), responsible for the synthesis of resveratrol, a phenol derivative linked to the health benefits of moderate wine consumption, are represented by a hugely inflated number of genes.
Photons meet neutrons
German state and federal officials have agreed to let two large radiation research centres in Berlin merge, a move that German Research Minister Annette Schavan said will make Berlin a world-class interdisciplinary centre for nanomaterials and solar energy research.
The Hahn-Meitner Institute (HMI), which focuses on solar energy and structural research by using neutron beams as probes, will merge in January 2009 with the smaller Bessy (Berlin Electron Storage Ring for Synchrotron Radiation) facility, which can deliver ultra-bright photon beams from long-wave terahertz waves right through to hard x-rays. The new combined centre will operate with an annual budget of
Schavan said the combined centre would be comparable to the European Synchrotron Radiation Facility in Grenoble, France, the Rutherford Labs in the UK or the Paul Scherrer Institute in Switzerland.
Troublesome dopants spotted
US researchers who have drawn up the first 3D maps of individual atoms in a semiconductor hope their research will help shrink silicon transistors even further.
Dopant atoms are added to silicon semiconductors to provide electrons, but they tend to cluster together - affecting transistor performance as the devices get smaller. Until now it had been impossible to trace their movements in detail, but a team from Madison-based Imago Scientific Instruments used atom probe tomography (APT) to locate individual atoms of dopant. They reported in Science (DOI: 10.1126/science.1145428) that arsenic dopants formed spheroidal clusters around defects in the silicon lattice.
A successful Ely Lilly drug trial could herald the arrival of the first new class of schizophrenia drug for over 50 years. While current medicines all work the same way, lowering dopamine levels in the brain, the experimental drug, so far known only as LY2140023, targets glutamate, a different neurotransmitter.
The trial, reported in Nature Medicine (DOI: 10.1038/nm1632), showed LY2140023 is about as effective as the best current treatments available, but doesn’t trigger the unpleasant side effects for which dopamine-targeting drugs have become notorious, which include weight gain and tremors.
Schizophrenia affects 1 per cent of the world’s population and has a broad range of symptoms, from hallucinations and delusions to social withdrawal and apathy.
Nanoparticles paint finer picture
Swiss scientists have developed a process that can print detailed images using nanoparticles as ’ink’, while maintaining their catalytic and optical properties.
Led by Tobias Kraus at the IBM Zurich Research Laboratory, and publishing in Nature Nanotechnology (DOI: 10.1038/nnano.2007.262), the team demonstrated their technique by using gold nanoparticles to print a picture of the sun - the alchemical symbol for gold, designed by seventeenth-century alchemist Robert Fludd. This tiny piece of nano-art is made up of 20,000 gold particles, each around 60nm in size, and took 12 minutes to print.
Standard gravure printing involves covering etched plates with ink; then scraping off the excess, leaving ink in the grooves, which can then be pressed onto a printing surface. In the new technique, researchers spray a thin layer of nanoparticles on the plates and leave them to fall into the grooves. After the ’ink’ dries, a thin polymer layer fixes the nanoparticles onto the target surface, producing pictures thousands of times more detailed than conventional methods.