| Inflammation Brings on the Blues As if being stuck sick in bed wasn’t bad enough, several studies conducted during the past few years have found that the immune response to illness can cause depression. Recently scientists have pinpointed an enzyme that could be the culprit, as it is linked to both chronic inflammation--such as that found in patients with coronary heart disease, type 2 diabetes and rheumatoid arthritis--and depressive symptoms in mice.In the new study, immuno­physiologist Keith Kelley and his colleagues at the University of Illinois exposed mice to a tuberculosis vaccine that produces a low-grade, chronic inflammation. After inocu­lation, production in the mice brains of an enzyme called IDO, which breaks down tryptophan, spiked. The animals exhibited normal symptoms of illness such as moving around and eating less. Yet even after recovering from the physical illness induced by the vaccine, they showed signs of depression--for example, struggling less than control mice to escape from a bucket of water. Surprisingly, their listlessness was solved relatively simply. “If you block IDO, genetically or pharmaceutically, depression goes away” without interfering with the immune response, Kelley explains. [More] rss.sciam.com |
Can We Feed and Save the Planet? We are eating ourselves out of house and home. Recently, in the September 24 issue of Nature , Johan Rockström and his colleagues proposed 10 “planetary boundaries” to define safe limits of human activity. ( Scientific American is part of the Nature Publishing Group.) Those limits include caps on greenhouse gas emissions, biodiversity loss, the global conversion of land cover to cropland, and other mega-impacts on the earth’s ecosystems. Yet humanity has already exceeded several of them and is on a trajectory to exceed most of the others. The rising demand for food plays a large role in those transgressions.The green revolution that made grain production soar gave humanity some breathing space, but the continuing rise in population and demand for meat production is exhausting that buffer. The father of the green revolution, Norman Borlaug, who passed away in September at the age of 95, made exactly this point in 1970 when he accepted the Nobel Peace Prize: “There can be no permanent progress in the battle against hunger until the agencies that fight for increased food production and those that fight for population control unite in a common effort.” [More] rss.sciam.com |
Measuring iron's importance to ocean life Editor's Note: Journalist and crew member Kathryn Eident and scientist Jeremy Jacquot are traveling on board the RV Atlantis on a monthlong voyage to sample and study nitrogen fixation in the eastern tropical Pacific Ocean, among other research projects. This is the fourth blog post detailing this ongoing voyage of discovery for ScientificAmerican.com . [More] rss.sciam.com |
Fatal Accident at Central Park Puts Focus on Trees Questions on Central Park’s operations have been raised after a branch killed a baby and injured her mother. nytimes.com |
Flower Power: Genetic Modification Could Amply Boost Plants' Carbon-Capture and Bioenergy Capacity Human activities currently add about nine gigatons of carbon to the atmosphere yearly. Photosynthetic organisms on land and in the ocean absorb about five of those gigatons through the natural uptake of CO2, leaving to humans the task of dealing with the rest. But no matter how much carbon there is, capturing it and preventing it from reentering the atmosphere is an immense engineering challenge; even today's best technology is orders of magnitude less effective than photosynthesis at trapping atmospheric carbon.A new analysis published in the October issue of Bioscience suggests that by 2050 humans could offset between five and eight gigatons of the carbon emitted annually by growing plants and trees optimized via genetic engineering both for fuel production and carbon sequestration . [More] rss.sciam.com |