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Studying the Wonders of Spider Silk
Researcher Cheryl Hayashi holds a spider. She is investigating the genetics of complex spider silk-making. Credit: Strategic Communications, UC Riverside
Most people don't spend a lot of time thinking about spiders, but Cheryl Hayash is the exception. A professor of biology at the University of California, Riverside (UCR), Hayashi supervises the researchers in her laboratory who are doing extensive work on spiders and in particular -- their silk.
Nearly all spiders make several kinds of silk to move. to trap and store food, and toreproduce. Most silks are less than one-tenth the diameter of a human hair, lighter than cotton, yet ounce for ounce up to five times tougher than steel. As a result, they are being considered for improving a wide variety of products such as lightweight, super-strong body armor, specialty rope, biodegradable surgical sutures and components of medical devices.
Spider silk is created through a very complicated and extraordinary process. A viscous liquid of several proteins is dehydrated and then made to flow out of the spider in a dry, continuous fiber that is extremely strong and flexible.
"Different proteins are made and mixed in the silk glands of spiders to create the silk," Hayashi says. "It is a combination of the exact sequence of the individual proteins and the way these proteins interact and link with each other that gives silk its remarkable strength. People have tried to mimic its production in the lab--for example, by squeezing these proteins through a narrow syringe--but what they've ended up with was something thick and brittle, not the fine and flexible material that is spider silk."
Hayashi continues, "Whenever you need something strong and lightweight, spider silk can be a good candidate. For example, making a thin film or a thin fabric. Or as scaffolds to re-grow tissue. Silk is being seriously explored for use in bullet-proof vests. Down the road, I see silk being used in textiles for high-performance, durable clothing. Spider silk's advantages are its softness and flexibility, qualities you need for making items such as high-tech athletic attire and ultra-tough patches to cover areas around body joints."
Tangentially, her fascination with spider silk has also lead to evidence indicating that spiders' spiraling webs are so old that dinosaurs may have seen them! In fact, spider silk itself has been around for more than 350 million years and as spiders evolved, their silks changed dramatically over time.
Source: The National Science Foundation,www.nsf.org
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Researcher Daniel Bond studies the electricity-producing Geobacter, a microbe that can be found beneath bodies of water. Photo credit: Tim Rummelhoff
Bacteria Batteries?
Maybe a humble bacteria holds the key to energy independence! Daniel Bond, a microbiologist at the University of Minnesota-Twin Cities, and his team are studying a species of bacteria known as, Geobacter sulfurreducens. This remarkable bacteria produces an electric current when it is attached to a graphite electrode or other conductive surface.
A traditional battery or a hydrogen fuel cell requires a precious-metal catalyst such as platinum to strip electrons off the fuel source and pull them onto the electrode to generate electricity. Geobacter requires only graphite, an inexpensive and widely available form of carbon, to accomplish the same feat.
"Other species of bacteria may produce just as many electrons as they oxidize available fuels, but their cell membranes act like an insulator for electron transport," said Daniel Bond, a microbiologist at the University of Minnesota-Twin Cities. Geobacter has proteins that guide electrons all the way to the electrode. "This makes Geobacter unique in comparison to other bacteria," Bond said.
Bond's group will continue to explore ways to improve Geobacter's usefulness in energy, sensors and environmental cleanup, but they also want to understand better just how the bug does what it does.
Geobacter's current capability already has been harnessed in so-called "microbial fuel cells" that use bacteria to convert wastewater organic compounds into electricity. "Part of our lab is working to scale-up the technology, but most of the work focuses on 'how' and 'why,'" Bond said.
Source: The National Science Foundation,www.nsf.org.
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Genetically Modified (GM) Foods Proven to Pose Health and Reproductive Hazards
A long-term feeding study commissioned by the Austrian Agency for Health and Food Safety confirms genetically modified (GM) corn seriously affects reproductive health in mice.
Non-GMO advocates, who have warned about this infertility link along with other health risks, now seek an immediate ban of all GM foods and GM crops to protect the health of humankind and the fertility of women around the world.
Feeding mice with genetically modified corn developed by the US-based Monsanto Corporation led to lower fertility and body weight according to the study conducted by the University of Veterinary Medicine in Vienna. Lead author of the study Professor Zentek said there was a direct link between the decrease in fertility and the GM diet, and that mice fed with non-GM corn reproduced more efficiently.
Other studies have also found that offspring of rats fed GM soy showed a five-fold increase in mortality, lower birth weights and the inability to reproduce.
Genetic Roulette, a book by author Jeffrey M. Smith and distributed to members of Congress last year, documents 65 serious health risks of GM products. Additionally, over the last two months, investigators in India have documented fertility problems, abortions, premature births and other serious health issues, including deaths, among buffaloes fed GM cottonseed products. For a wonderful, printable guide to Non-GM foods, to go: http://www.responsibletechnology.org/documentFiles/144.pdf - Editors.
Source: Institute for Responsible Technology, www.responsibletechnology.org.
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