The structure of one of the basic members of the cell-membrane water-channel family, a protein called aquaporin 1 (AQP1), has been determined to a resolution of 2.2 angstroms (22 billionths of a meter).
The structure reveals the elegantly simple means by which AQP1 can transport water through the cell membrane at a high rate while effectively blocking everything else, even individual protons, the nuclei of hydrogen atoms.
Biophysicist Bing Jap led a team from Lawrence Berkeley Nat
Urban wildlife may not use green corridors.
Green corridors do little to aid wildlife, say UK ecologists. Their discovery that isolated wild ground contains just as many plant species as do patches linked by continuous greenery casts doubt on current conservation priorities.
“The proportion of organisms that use [wildlife corridors] is exceedingly small,” says botanist Mark Hill of the Centre for Ecology and Hydrology in Monks Wood. Only vertebrates seem to benefit, he says.
Meteorites could have sweetened the earliest life.
Sugar from space may have nourished the first life on Earth. Two meteorites contain a range of polyols, organic substances closely related to sugars such as glucose 1 .
George Cooper of NASA’s Ames Research Center in California and co-workers have found these compounds in the Murchison meteorite, which fell over the Australian town Murchison in 1969, and in the Murray meteorite, that fell to Kentucky in 1950.
The tell-tale signature of most lasers used in everyday applications—from bar-code scanners to pen-size pointers—is a bright red glow. The color is determined by the light’s wavelength, and most lasers emit at only one wavelength. Now a new report published in the current issue of the journal Nature describes a light source measuring only tens of millimeters across that changes color according to temperature.
To make the new laser, Diederik Wiersma and Stefano Cavalieri of the European
A vaccine against one of the world’s leading killers could one day be manufactured by livestock, researchers report. According to a study released today by the Proceedings of the National Academy of Sciences, scientists have developed mice that secrete malaria vaccine proteins into their milk. The purified experimental vaccine protected 80 percent of monkeys subsequently exposed to a lethal dose of the malarial parasite.
Anthony Stowers and Louis Miller of the National Institute of All
A fast, sensitive laboratory test that measures the molecular components involved during the critical moment when HIV infects a normal cell has been developed.
The advance was made by researchers in the University of California, San Diego (UCSD) School of Medicine and VA San Diego Healthcare System.
Described in the December 2001 issue of the Journal of Biological Chemistry (JBC), the test makes it possible to study and design new compounds to block the action of these molecular componen
Without the help of fossils or any other record from the distant past, scientists have identified what they believe represents a common ancestor of all animals on Earth, a microscopic organism with key genetic traits that, until now, have been found only in true animals.
Writing in Tuesday’s Proceedings of the National Academy of Sciences, a team of scientists from the Howard Hughes Medical Institute at the University of Wisconsin-Madison reports the discovery of a key cell communication ge
A solar slump may have chilled the Northern Hemisphere.
The flickering sun may cause rapid climate change, according to a new comparison of climate records. A 200-year cold snap 10, 300 years ago seems to have coincided with a passing slump in the sun’s activity 1 .
Svante Bjorck of Lund University in Sweden and colleagues looked at sediments in Lake Starvatn on the Faroe Islands and in the Norwegian Sea, the width of growth rings in ancient German pine trees
New techniques that might allow magnetic resonance imaging (MRI), to be used to give doctors subtle information about a tumour’s physiology and how it reacts to drug therapy are being developed.
The work is being carried out by doctors and medical physicists at the University of Aberdeen, with funding from the Swindon based Engineering and Physical Sciences Research Council.
Doctors treating cancerous tumours with drugs need to know quickly if the drug is having the desired effect t
Strands of hair accurately measure second hand tobacco smoke exposure, finds research in the Journal of Epidemiology and Community Health. And they may be more effective than currently used methods, suggest the authors.
Measuring levels of cotinine, a break-down product of nicotine, in the urine is often used to gauge second hand smoke exposure. But people vary considerably in how much of this substance they metabolise and eliminate, whatever their levels of exposure, and cotinine stays in t
Taking up regular drinking in middle age might cut the risk of heart disease, finds research in Heart. But the catch is, it increases the risk of dying from something else.
The researchers studied 7735 men from general practices in 24 British towns. The men were screened for heart disease between 1978 and 1980 when they were aged between 40 and 59. And they were asked about lifestyle, including smoking and drinking, and their medical history. Five years later, 7157 of them completed question
Logic dictates that when you increase the pressure acting on a material, it should compact. So a report from an international team of scientists that they have discovered a crystal formation that expands under pressure is intriguing. The counterintuitive behavior may be exploited to make a crystal sponge for chemical cleanup.
Writing in the December 19 issue of the Journal of the American Chemical Society, the researchers describe the behavior of natrolite, a type of zeolite, under increasi
Using tiny rust-containing spheres to tag cells, scientists from Johns Hopkins and elsewhere have successfully used magnetic resonance imaging to track stem cells implanted into a living animal, believed to be a first.
In the December issue of the journal Nature Biotechnology, the research team report that the neuronal stem cells take up and hold onto the spheres, which contain a compound of iron and oxygen. The iron-laden cells create a magnetic black hole easily spotted by magnetic resonan
Sloshing proteins help bacteria find their waists.
Chemical waves may help a bacterium to divide by pinpointing its middle, according to a new model of protein interactions 1 .
Bacteria such as Escherichia coli multiply by dividing. Bacterial division (called binary fission) is simpler than human cell division (mitosis). Human cells erect scaffolding to transport components to the two nascent daughter cells at either end; bacteria just pinch in two.
According to a new study, when it comes to smoking, adolescents may be emulating the movie stars they see on the big screen. Writing in the December 15 issue of the British Medical Journal, researchers at Dartmouth College report that they have found a link between tobacco use in movies and smoking amongst young people.
James D. Sargent and colleagues questioned 4,919 New England middle school students between the ages of nine and 15 about their smoking habits and movies they had seen. “For
Residual heat from volcanic activity may be causing a river of ice to flow in Greenland, a new study indicates. Geologists have found that the region directly above a stream of relatively fast moving ice is thinner than a simple model of glacier change would predict. This observation, described in a report published today in the journal Science, may help researchers pin down the contribution ice sheets have made to sea level changes.
Glaciers are built up from layers of fused snow that spr
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