On February 6, a U.S. Food and Drug Administration approved a drug made by genetically modified animals—in this case, transgenic goats from Framingham, Mass.–based GTC Biotherapeutics. The goats generate the human protein antithrombin, which inhibits clotting. Called ATryn, the drug was already approved in Europe in 2006 [see “The Land of Milk and Money”; SciAm, November 2005, and “Old MacDonald’s Pharm”; SciAm, September 2006]. The company says that 150 transgenic goats could produce 100 kilograms of a protein drug a year for tens of millions of dollars. In comparison, a more conventional biotech system using vat-grown mammalian cells can run hundreds of millions in capital costs. Consumer advocates still voice caution, suggesting the FDA needs to ensure the goats do not enter the food supply.
—Charles Q. Choi
Columbia’s Last Moments
The final minutes of Columbia, which broke up on reentry on February 1, 2003, hold lessons for future vehicles [see “Rethinking the Shuttle”; SciAm, April 2003]. On December 30, 2008, NASA released its definitive report regarding the crew. Although the accident was not survivable by any means, the agency found several safety flaws.
Relying on video analysis, recovered debris, medical findings and computer modeling, investigators conclude that the crew had about 40 seconds to recognize the situation and act before losing consciousness because of cabin depressurization. Shoulder restraints failed, allowing the crew’s upper bodies to move as the cabin spun out of control. The pressure helmets did not conform to the astronauts’ heads, like motorcycle helmets would, so they afforded little protection from impact. The report states that uncontrolled motions led to “injuries and lethal trauma.”
For new spacecraft, the report recommends several changes, such as better restraints and parachutes that do not have to be activated by a conscious crew. More fundamentally, NASA needs to incorporate safety systems into the design from the get-go (pressure suits came about only after the Challenger accident in 1986). The sobering, 400-page report is available at www.nasa.gov/news/reports/index.html
The much debated fifth taste, umami, has slowly been building credibility since its discovery in 1908 by Japanese chemist Kikunae Ikeda; most scientists believed that it was a mix of the other four tastes [see “Magnifying Taste”; SciAm, August 2008]. But research in the past 10 years has uncovered details of how the receptor picks up glutamate, found in protein-heavy foods such as meat, fish and legumes, and delivers a savory sensation. A recent study reveals how the receptor, shaped like a Venus flytrap, snaps shut on glutamate and how two other molecules can act as umami enhancers by binding next to the receptor and keeping glutamate in it for longer. The study appears in the December 30, 2008, Proceedings of the National Academy of Sciences USA.
Spin to Swim
A goal in nanotechnology is a tiny engine that can power through blood vessels and microchip conduits, but fluid viscosity at this scale makes realizing such devices difficult [see “The Once and Future Nanomachine”; SciAm, September 2001]. A Spanish and British team has constructed tiny swimmers from beads made out of a plastic-magnetic material. The researchers used a short strand of DNA to connect a bead 2.8 microns wide with one (or more) that was a micron wide. A magnetic field can spin the beads, thereby moving them through narrow channels, the scientists report in the December 25, 2008, Journal of Physical Chemistry B.