Squid 'sight': Not just through eyesJune 02, 2009MADISON - It's hard to miss the huge eye of a squid. But now it appears that certain squids can detect light through an organ other than their eyes as well. That's what researchers at the University of Wisconsin-Madison report in the current issue (June 2) of the Proceedings of the National Academy of Sciences. The study shows that the light-emitting organ some squids use to camouflage themselves to avoid being seen by predators - usually fish sitting on the ocean floor - also detects light. The findings may lead to future studies that provide insight into the mechanisms of controlling and perceiving light. "Evolution has a 'toolkit' and when it needs to do a particular job, such as see light, it uses the same toolkit again and again," explains lead author Margaret McFall-Ngai, a professor of medical microbiology and immunology at the UW-Madison School of Medicine and Public Health (SMPH). "In this case, the light organ, which comes from different tissues than the eye during development, uses the same proteins as the eye to see light." In studying the squid for the past 20 years, McFall-Ngai and her colleagues have been drawn to the fact that the squid-light organ is a natural model of symbiosis - an interdependent relationship between two different species in which each benefits from the other. In this case, the light organ is filled with luminous bacteria that emit light and provide the squid protection against predators. In turn, the squid provides housing and nourishment for the bacteria. The UW-Madison researchers have been intrigued by the light organ's "counterillumination" ability - this capacity to give off light to make squids as bright as the ocean surface above them, so that predators below can't see them. "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," says McFall-Ngai. "Now we show that the E. scolopes squid has additional light-detecting tissue that is an integral component of the light organ." The researchers demonstrated that the squid light organ has the molecular machinery to respond to light cues. Molecular analysis showed that genes that produce key visual proteins are expressed in light-organ tissues, including genes similar to those that occur in the retina. They also showed that, as in the retina, these visual proteins respond to light, producing a physiological response. "We found that the light organ in the squid is capable of sensing light as well as emitting and controlling the intensity of luminescence," says co-author Nansi Jo Colley, SMPH professor of ophthalmology and visual sciences and of genetics. Adds McFall-Ngai, "The tissues may perceive environmental light, providing the animal with a mechanism to compare this light with its own light emission." McFall-Ngai's large research program into the relatively simple squid-light organ symbiosis aims to shed light on symbiosis affecting humans. "We know that humans house trillions of bacteria associated with components of eight of their 10 organ systems," she says. "These communities of bacteria are stable partners that make us healthy." University of Wisconsin-Madison |
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| Related Squid Current Events and Squid News Articles Brain power goes green Our brains, it turns out, are eco-friendly. A study published in Science and reviewed by F1000 Biology members Venkatesh Murthy and Jakob Sorensen reveals that our brains have the amazing ability to be energy efficient. Joint U.S. - Norwegian Study Provides New Insights into Marine Ecosystems and Fisheries Production NOAA and Norwegian researchers recently completed a comparative analysis of marine ecosystems in the North Atlantic and North Pacific to see what factors support fisheries production, leading to new insights that could improve fishery management plans and the ecosystems. URI researcher sheds light on 'man-eating' squid; finds them timid, non-threatening News reports last week about scuba divers off San Diego being menaced by large numbers of Humboldt's or jumbo squid have raised the ire of University of Rhode Island biologist Brad Seibel. Multiferroics -- making a switch the electric way Multiferroics are materials in which unique combinations of electric and magnetic properties can simultaneously coexist. Marine scientists return from expedition to erupting undersea volcano Scientists who have just returned from an expedition to an erupting undersea volcano near the Island of Guam report that the volcano appears to be continuously active, has grown considerably in size during the past three years, and its activity supports a unique biological community thriving despite the eruptions. Tentacles of venom: new study reveals all octopuses are venomous Once thought to be only the realm of the blue-ringed octopus, researchers have now shown that all octopuses and cuttlefish, and some squid are venomous. The work indicates that they all share a common, ancient venomous ancestor and highlights new avenues for drug discovery. Tiny but toxic: MBL researchers discover a mechanism of neurodegeneration in Alzheimer's disease Tiny, toxic protein particles severely disrupt neurotransmission and inhibit delivery of key proteins in Alzheimer's disease, two separate studies by Marine Biological Laboratory (MBL) researchers have found. Nanocups brim with potential Researchers at Rice University have created a metamaterial that could light the way toward high-powered optics, ultra-efficient solar cells and even cloaking devices. Single gene lets bacteria jump from host to host All life - plants, animals, people - depends on peaceful coexistence with a swarm of microbial life that performs vital services from helping to convert food to energy to protection from disease. Structure of enzyme against chemical warfare agents determined The enzyme DFPase from the squid Loligo vulgaris, is able to rapidly and efficiently detoxify chemical warfare agents such as Sarin, which was used in the Tokyo subway attacks in 1995. More Squid Current Events and Squid News Articles |
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