Bacteria give skin cells their marching orders.
Bacteria that cause potentially lethal ’flesh-eating’ infections make their entrance by telling skin cells to step aside. The bugs hijack the body’s signal for skin cells to become mobile.
Group A streptococci (GAS) normally infect the surface lining of the throat. But occasionally they penetrate skin or the tissues lining the airways, invading deep into the body and causing life-threatening disease.
Finding out how s
In 1998, Paul F. Hoffman and Daniel P. Schrag at Harvard University put forth a chilling description of earth’s climate some 650 million years ago. Their theory, dubbed snowball earth, held that between 750 million and 580 million years ago, ice repeatedly enveloped our planet, coating the seas from pole to pole and killing off early life almost completely. During the past few years, the idea has stirred up a great deal of debate. And new data published in the December issue of Geology only furt
Keeping parks pretty means tailoring the trees to their source of water.
Irrigation water recycled from sewage can damage many plant species, new research has found 1 . The results show that landscape architects should tailor their choice of plants to the type of water they will receive.
Dale Devitt of the University of Nevada at Reno and colleagues began studying the effects of different water sources on plants after reports that ’reuse’ water had damaged tr
Scientists at the University of Pennsylvania have identified a receptor that plays a key role in restricting embryonic stem cells’ pluripotency, their ability to develop into virtually any of an adult animal’s cell types.
The work is the first demonstration of a mechanism by which pluripotency is lost in mammalian embryos, one that operates with nearly the precision of an on/off switch in mouse embryos.
With further study, the receptor, dubbed GCNF, could open the door to new ways of c
For more than 150 years, people around the world have made ample use of the explosive trinitrotoluene, otherwise known as TNT. Its use has had unintended consequences, however: the manufacture, storage and disposal of TNT—which ranks among the most toxic explosives employed by the military—have left large areas of land contaminated and polluted. So far, effective and affordable cleanup technologies have remained out of reach. But new research suggests that help may come from what might seem an unlike
The question of which forces control terrestrial ecosystems lies at the heart of a long-standing debate among ecologists. One theory, the so-called bottom-up theory, suggests that plant defense mechanisms exert control by limiting food availability for herbivores. Top-down theorists, however, suggest that predators limit the numbers of herbivores and hence their impact on the vegetation. Now new findings in the current issue of the journal Science that describe animal communities isolated for 15 year
Radon may pose a greater cancer threat than has been thought.
Radon damage from irradiated cells spreads to their neighbours, a new study finds 1 . The result suggests that small amounts of this radioactive gas could cause widespread harm.
The study “is a reason for concern but not panic”, says Gerhard Randers-Pehrson of Columbia University, New York, a member of the team that performed the study. “We’re talking about the acceptable level of radon changing pe
A balanced portfolio of programs could mean a faster quantum computer.
Strategies from the world of finance could help get the best out of quantum computers, say US researchers 1 . The right portfolio of programs could solve a problem many times faster than a single strategem.
Quantum computers – purely hypothetical as yet – would be fast, but you could never be sure whether a program was going to work or not. You would have to keep running the program until
World’s smallest reptile is discovered in the Caribbean forest.
At just 16 mm from nose to tail, the Jaragua lizard is the world’s smallest. In fact, it’s the smallest vertebrate that can reproduce on dry land 1 .
The newly discovered lizard lives on Isla Beata, a small, forest-covered island in the Caribbean off the Dominican Republic. Blair Hedges, an evolutionary biologist at Pennsylvania State University, together with Richard Thomas of the
In news that will surely fan the flames of the heated debate over genetically modified crops, scientists have found evidence that genes from GM plants can spread far and wide to native ones. According to a report published today in the journal Nature, wild corn from the remote mountains of Oaxaca, Mexico contains transgenic DNA. This, the researchers note, bolsters concerns that such unintentional contamination can threaten the genetic diversity of natural crops.
DNA analyses of the Oaxaca
Generally speaking, we go to great lengths to rid our bodies of foreign bacteria, whether it’s by brushing our teeth, washing our hands or taking antibiotics. But new research suggests that when it comes to treating tumors, we may one day invite the bugs in. According to a study published yesterday in the early online edition of the Proceedings of the National Academy of Sciences, a bacterium that normally resides in soil, dust and dead flesh quickly destroys large tumors in mice when injected along
Surprising black hole weigh-in has astronomers scratching their heads.
Forty thousand light years away, on the other side of the Milky Way, lies object GRS1915+105. It is a giant star and a black hole orbiting one another, blasting out X-rays and ejecting gas and dust at close to the speed of light.
Now measurements of this “extreme and puzzling” object are casting doubt on current theories of how such binary systems form and behave. Astronomers have weighed its black hole,
New research is helping to unravel the machinery that allows a mosquito to sniff out its human quarry, which could lead to more and better ways of foiling the disease-spreading insects. A report published today in the online version of the Proceedings of the National Academy of Sciences describes four genes that appear to produce odor-sensing molecules in Africa’s Anopheles gambiae, a carrier of malaria, the number two killer in the developing world. Understanding how such genes operate could en
The size and types of the largest local land animals vary greatly from place to place, prompting scientists to question what controls the success of animals of certain sizes over others. Now a report published in the current issue of the Proceedings of the National Academy of Sciences shows that the size of a landmass limits the maximal body size of its top animal.
Gary Burness and Jared Diamond of the University of California School of Medicine, together with Timothy Flannery of the South
Rewiring the egg: mechanism remains murky.
From a scientific viewpoint, the cloning of human embryos may be more of a step than a leap, say sceptics. If the signals that turn adult cells into embryonic ones can be found, the creation of cloned embryos for tissue repair may become redundant.
Researchers at Advanced Cell Technology (ACT) in Worcester, Massachusetts, now report that they have created cloned human embryos. They aimed to make blastocysts, hollow balls of cells fr
Hubble spots atmosphere on planet 150 light years away.
Astronomers have glimpsed the atmosphere of a planet in a solar system other than our own for the first time. The feat is a first step towards detecting planets capable of supporting life elsewhere in the Universe.
David Charbonneau, of the California Institute of Technology, Pasadena, and colleagues, pointed the Hubble space telescope at the planet, which lies 150 light years away in the constellation Pegasus. Of the 7
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