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Excess production of a protein could underlie depression
Frederic Courbet/Panos
IN BRIEF Family dinners, T. rex style
Worm vaccine may help the one but harm the many PARASITIC worms can adjust their survival strategy based on their host’s immune response. This means potential vaccines against elephantiasis might make the infection spread more easily through communities. Elephantiasis infects 120 million people a year in Africa and Asia. Tiny filaria worms carried by mosquitoes block the lymph vessels that normally drain fluid from limbs or genitals, which then swell to grotesque proportions. The only prevention is a yearly dose of worming drugs, but fewer than half the people at risk receive them. Work is under way on a vaccine, but Simon Babayan
at the University of Edinburgh, UK, and colleagues, have discovered that some vaccines may make the worms worse. When filaria worms in mice sense that the mouse is mounting a strong immune reaction, they change their life cycle, producing more offspring in the blood earlier. This helps the worm ensure that it will be picked up and transmitted by another mosquito despite the immune attack (PLoS Biology, DOI: 10.1371/journal.pbio.1000525). Unfortunately, experimental vaccines rely on the very immune reactions that warn the worms, Babayan says. People who get such a vaccine may defeat their own infection, but the worms’ early response means they will pass on more infections. Babayan says potential vaccines should be tested for whether their targets adapt to them in this way.
New target for antidepressants A PROTEIN involved in the growth and development of brain cells could play a role in depression and provide a possible target for antidepressants. Ron Duman and colleagues at Yale University began their search for a mechanism behind depression by comparing post-mortem brain samples from 21 people who had been depressed and 18 people of the same age.
The group looked for differences in gene expression by comparing levels of messenger RNA – the middle-man between gene and protein production – throughout the entire genome. While Duman’s team found several hundred differences, most striking were levels of mRNA for a particular protein, MKP-1, which inhibits a pathway involved in neural growth and development.
The brains of people with depression contained twice the amount of other people. When the group over-expressed the gene for MKP-1 in the brains of healthy rats, the animals began to show signs of depression which disappeared when treated with an antidepressant (Nature Medicine, DOI: 10.1038/nm.2219). “[The findings] suggest a novel target for drug development,” says Steven Garlow at Emory University in Atlanta, Georgia.
Tyrannosaurus rex may not have been the legendary predator portrayed in Jurassic Park, but one thing is now clear: the fearsome dinosaur was a cannibal. Nicholas Longrich of Yale University was examining T. rex bones when he found that four bore large tooth marks that could only have been made by another big predatory dinosaur. All four come from western North America, and T. rex was the only predator around at the time that was large enough to leave the marks. The most likely explanation is that the toothy giant was a cannibal, says Longrich (PLoS One, DOI: 10.1371/journal. pone.0013419). David Varricchio of Montana State University in Bozeman agrees. “It’s very unlikely that a second large species has gone undetected,” he says, as North American fossil beds have been thoroughly investigated.
Asteroid hits will destroy ozone layer IF A 1-kilometre-wide asteroid lands in the ocean, tsunamis won’t be our only worry. A simulation suggests that the vapour and salt thrown up by the impact could damage the ozone layer, leading to record levels of ultraviolet radiation that could threaten human civilisation. Elisabetta Pierazzo of the Planetary Science Institute in Tucson, Arizona, and colleagues used a global climate model to study the effect of an impact. They found that water vapour and chlorine and bromine from vaporised sea salts would destroy ozone high in Earth’s atmosphere at a much faster rate than it is naturally created (Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2010.08.036). 23 October 2010 | NewScientist | 17
IN BRIEF Family dinners, T. rex style
Worm vaccine may help the one but harm the many PARASITIC worms can adjust their survival strategy based on their host’s immune response. This means potential vaccines against elephantiasis might make the infection spread more easily through communities. Elephantiasis infects 120 million people a year in Africa and Asia. Tiny filaria worms carried by mosquitoes block the lymph vessels that normally drain fluid from limbs or genitals, which then swell to grotesque proportions. The only prevention is a yearly dose of worming drugs, but fewer than half the people at risk receive them. Work is under way on a vaccine, but Simon Babayan
at the University of Edinburgh, UK, and colleagues, have discovered that some vaccines may make the worms worse. When filaria worms in mice sense that the mouse is mounting a strong immune reaction, they change their life cycle, producing more offspring in the blood earlier. This helps the worm ensure that it will be picked up and transmitted by another mosquito despite the immune attack (PLoS Biology, DOI: 10.1371/journal.pbio.1000525). Unfortunately, experimental vaccines rely on the very immune reactions that warn the worms, Babayan says. People who get such a vaccine may defeat their own infection, but the worms’ early response means they will pass on more infections. Babayan says potential vaccines should be tested for whether their targets adapt to them in this way.
New target for antidepressants A PROTEIN involved in the growth and development of brain cells could play a role in depression and provide a possible target for antidepressants. Ron Duman and colleagues at Yale University began their search for a mechanism behind depression by comparing post-mortem brain samples from 21 people who had been depressed and 18 people of the same age.
The group looked for differences in gene expression by comparing levels of messenger RNA – the middle-man between gene and protein production – throughout the entire genome. While Duman’s team found several hundred differences, most striking were levels of mRNA for a particular protein, MKP-1, which inhibits a pathway involved in neural growth and development.
The brains of people with depression contained twice the amount of other people. When the group over-expressed the gene for MKP-1 in the brains of healthy rats, the animals began to show signs of depression which disappeared when treated with an antidepressant (Nature Medicine, DOI: 10.1038/nm.2219). “[The findings] suggest a novel target for drug development,” says Steven Garlow at Emory University in Atlanta, Georgia.
Tyrannosaurus rex may not have been the legendary predator portrayed in Jurassic Park, but one thing is now clear: the fearsome dinosaur was a cannibal. Nicholas Longrich of Yale University was examining T. rex bones when he found that four bore large tooth marks that could only have been made by another big predatory dinosaur. All four come from western North America, and T. rex was the only predator around at the time that was large enough to leave the marks. The most likely explanation is that the toothy giant was a cannibal, says Longrich (PLoS One, DOI: 10.1371/journal. pone.0013419). David Varricchio of Montana State University in Bozeman agrees. “It’s very unlikely that a second large species has gone undetected,” he says, as North American fossil beds have been thoroughly investigated.
Asteroid hits will destroy ozone layer IF A 1-kilometre-wide asteroid lands in the ocean, tsunamis won’t be our only worry. A simulation suggests that the vapour and salt thrown up by the impact could damage the ozone layer, leading to record levels of ultraviolet radiation that could threaten human civilisation. Elisabetta Pierazzo of the Planetary Science Institute in Tucson, Arizona, and colleagues used a global climate model to study the effect of an impact. They found that water vapour and chlorine and bromine from vaporised sea salts would destroy ozone high in Earth’s atmosphere at a much faster rate than it is naturally created (Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2010.08.036). 23 October 2010 | NewScientist | 17