Syndicate content

Archive - Jun 1, 2009

Light-Emitting Organ of Squid Also Senses Light

In addition to their prominent eyes that sense light, some squid have an organ that emits light. This light organ contains symbiotic luminous bacteria that produce light that is used by the squid to avoid predators. The light is believed to make the squid appear as bright as the ocean surface above them and thus obscure them from predators below. Now, researchers at the University of Wisconsin-Madison have obtained evidence that the light-emitting organ also senses light. "Until now, scientists thought that illuminating tissues in the light organ functioned exclusively for the control of the intensity and direction of light output from the organ, with no role in light perception," said lead author Dr. Margaret McFall-Ngai. "Now we show that the E. scolopes squid has additional light-detecting tissue that is an integral component of the light organ." Dr. McFall-Ngai added that "the tissues may perceive environmental light, providing the animal with a mechanism to compare this light with its own light emission." The findings may lead to future studies that provide insight into the mechanisms of controlling and perceiving light. The work was published in the June 2 issue of PNAS. [Press release]

Silver Nanoparticles Show Promise in Preventing Blood Clots

Working with mice, scientists have shown that the injection of silver nanoparticles 1/50,000 the diameter of a human hair can reduce the ability of platelets to clump together by more than 40 percent, with no apparent harmful side effects. The scientists suggested that such an approach might provide a new alternative to aspirin and other anti-platelet agents widely used to prevent blood clots in coronary artery disease, heart attack, and stroke. The authors noted that patients urgently need new anti-clotting agents because traditionally prescribed medications too often cause dangerous bleeding. At the same time, aging of the population, sedentary lifestyle, and spiraling rates of certain diseases have increased the use of these drugs. Researchers are presently seeking treatments that more gently orchestrate the activity of platelets, disk-shaped particles in the blood that can form clots. The nanoparticles "hold immense potential to be promoted as an antiplatelet agent," the researchers noted. "Nanosilver appears to possess dual significant properties critically helpful to the health of mankind—antibacterial and antiplatelet—which together can have unique utilities, for example in coronary stents." This study is scheduled for publication in the June 23 issue of the monthly journal American Chemical Society Nano. [Press release]