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Archive - Dec 15, 2013

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Disrupting of Quorum-Sensing Messages May Combat Sleeping Sickness

A new discovery by scientists could help combat the spread of sleeping sickness. Insights into how the parasites that cause the disease are able to communicate with one another could help limit the spread of the infection. The findings suggest that new drugs could be designed to disrupt the flow of messages sent between these infectious microorganisms. Sleeping sickness – so named because it disrupts sleep patterns – is transmitted by the bite of the tsetse fly, and more than 69 million people in Africa are at risk of infection. Untreated, it can damage the nervous system, leading to coma, organ failure, and death. During infection, the parasites – known as African trypanosomes – multiply in the bloodstream and communicate with each other by releasing a small molecule. When levels of this molecule become sufficiently high, this acts as a signal for the parasites to stop replicating and to change into a form that can be picked up by biting flies and spread. A team led by researchers at the University of Edinburgh was able to uncover key components of the parasites' messaging system. They used a technique known as gene silencing, to identify those genes that are used to respond to the communication signals and the mechanisms involved. Professor Keith Matthews, of the University of Edinburgh's School of Biological Sciences, who led the research, said: "Parasites are adept at communicating with one another to promote their survival in our bodies and ensure their spread – but by manipulating their messages, new ways to combat these infections are likely to emerge." The research, carried out in collaboration with the University of Dundee, was published online on December 15, 2013 in Nature, and funded by the Wellcome Trust.

Researcher Traces History of American Urban Squirrel

Until recently, Dr. Etienne Benson, an assistant professor in the University of Pennsylvania's Department of History and Sociology of Science, has trained his academic eye on the history of conservation of large, charismatic wildlife, such as tigers, grizzly bears, and orcas. With his latest publication, however, he consciously chose to investigate a creature that may be considered less exotic, and is certainly smaller. "I wanted to write about something a bit closer to home, about things we see and encounter every day," Dr. Benson said. "I wanted to shift the focus to the urban and the quotidian and, in some sense, the trivial, to see what we can learn by looking at trivial nature, or nature that is at risk of being interpreted as trivial." So he turned his attention to the squirrel. His paper, "The Urbanization of the Eastern Gray Squirrel in the United States," published in the December 2013 issue of the Journal of American History (also note podcast at link below), examines how the now-ubiquitous bushy-tailed creatures found homes in American cities, and how their presence there altered people's conceptions of nature and community. Dr. Benson explains that though many people may think that squirrels have simply persisted in urban landscapes since Europeans arrived in the U.S., their presence is actually the result of intentional introductions. "By the mid-19th century, squirrels had been eradicated from cities," he said. "In order to end up with squirrels in the middle of cities, you had to transform the urban landscape by planting trees and building parks and changing the way that people behave. People had to stop shooting squirrels and start feeding them." In researching the history of squirrels in American cities, Dr.

Extensive Variability in Olfactory Receptors Influences Human Odor Perception

A difference at the smallest level of DNA -- one base pair coded for by one gene -- can determine whether you find a given smell pleasant. A different base pair coded for by the same gene in your friend's body could mean he finds the same odor offensive, according to researchers at Duke University and collaborators from Monell Chemical Sciences Center, the University of Pennsylvania School of Medicine, and Rockefeller University. There are approximately 400 genes coding for the receptors in our noses, and according to the 1000 Genomes Project, there are more than 900,000 variations of those genes. These receptors control the sensors that determine how we smell odors. A given odor will activate a suite of receptors in the nose, creating a specific signal for the brain. But the receptors don't work the same for all of us, said Hiroaki Matsunami, Ph.D., associate professor of molecular genetics and microbiology at the Duke University School of Medicine. In fact, when comparing the receptors in any two people, they should be about 30 percent different, said Dr. Matsunami, who is also a member of the Neurobiology Graduate Program and the Duke Institute for Brain Sciences. "There are many cases when you say you like the way something smells and other people don't. That's very common," Dr. Matsunami said. But what the researchers found is that no two people smell things the same way.