The genetics behind near-sightedness are coming into focus.
In studies (1, 2) in Nature Genetics that looked at more than 4,000 people, scientists report that variations in a gene called RASGRF1 are partly responsible for whether or not a person develops myopia.
“It is not quite the end of glasses yet but clearly the hope is that we will be able to block the genetic pathways that causes shortsightedness,” said Dr Christopher Hammond at King’s College London, an eye surgeon who led the British research. [The Telegraph]
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When an archer fish gets peckish and goes hunting for a juicy insect meal, it cruises toward the water’s surface with its ammunition packed in its mouth: As soon as it spots an insect above the surface, it fires out a jet of spit. This remarkable marksman has been known to bring down insects hanging from tree limbs as high as 3 feet above the water’s surface. And according to a study just published in the Proceedings of the National Academy of Sciences, it uses a visual processing technique that was previously thought to exist only in mammals.
The study found that fish pay attention to something called orientation saliency, which means that fish can more easily spot an object that is oriented differently from its background. The researchers first trained some archer fish to spit at the image of an insect projected on a LCD screen above their tanks, then presented images of objects that were either aligned with or perpendicular to a patterned background. They found that the fish spit far more accurately at objects that were not lined up with the background. (See video of a spitting fish in the lab below.)
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From “When the Robots Sing ‘Touch-A, Touch-A, Touch-Me,’ the E-Skin Is Working,” on the DISCOVER blog Science Not Fiction:
That’s right, e-skin. A group of scientists at UC-Berkeley devised a flexible mesh using nanowires to create a substance that reacts to pressure, and, as their paper in Nature Materials said, “effectively functions as an artificial electronic skin.” In the same issue, a team from Stanford University announced it had devised a kind of skin so sensitive, it can detect the weight of a bluebottle fly. All of which means for one shining issue, a scientific journal was a skin mag.
Read the rest of this post (with video).
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Image: UC Berkeley
From Ed Yong:
Right from its entrance, Disneyland is designed to cast an illusion upon its visitors. The first area – Main Street – seems to stretch for miles towards the towering castle in the distance. All of this relies on visual trickery. The castle’s upper bricks and the upper levels of Main Street’s buildings are much smaller than their ground-level counterparts, making everything seem taller. The buildings are also angled towards the castle, which makes Main Street seem longer, building the anticipation of guests.
These techniques are examples of forced perspective, a trick of the eye that makes objects seem bigger or smaller, further or closer than they actually are. These illusions were used by classical architects to make their buildings seem grander, by filmmakers to make humans look like hobbits, and by photographers to create amusing shots. But humans aren’t the only animals to use forced perspective. In the forests of Australia, the male great bowerbird uses the same illusions to woo his mate.
Read the rest of this post at Not Exactly Rocket Science.
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Image: Current Biology / John Endler
Six patients’ eyes have connected with “biosynthetic” replacement corneas, growing nerves and cells into the fakes as if they were real human tissue. With more trials and improvements in implant technique, researchers say the biosynthetic corneas might replace the expensive, rejection-prone, and scarce cadaver corneas that are currently used in transplants. This is good news for people who have lost vision due to inflamed or scarred corneas, and who are hoping to bring the world back into focus.
The findings appeared yesterday in Science Translational Medicine. The corneas allowed six out of a total of ten trial patients with advanced keratoconus, a condition which causes corneal scarring, to see just as well as if they had a traditional cadaver cornea replacement. Natural corneas, which refract light coming into the eye and help it to focus, consist of parallel strands of collagen; the biosynthetic corneas used collagen made in a lab by the biotech company Fibrogen.
“This study … is the first to show that an artificially fabricated cornea can integrate with the human eye and stimulate regeneration,” said May Griffith of the Ottawa Hospital Research Institute, who led the study. “With further research, this approach could help restore sight to millions of people who are waiting for a donated human cornea for transplantation.” [Reuters]
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Researchers have found the secret to improving a robot’s sense of smell: Shove frog eggs up its nose. A team at the University of Tokyo has developed a sensor made from a genetically modified frog egg that can help a robot pick out insect smells and pheromones.
As useful as a moth-smelling robot may seem, researchers believe the study published yesterday in Proceedings of the National Academy of Sciences is just one step towards an inexpensive but sensitive chemical detector. Study coauthor Shoji Takeuchi explains that such a device could pick out gases like carbon dioxide:
“When you think about the mosquito, it is able to find people because of carbon dioxide from the human. So the mosquito has CO2 receptors. When we can (extract) DNA (from the mosquito) we can put this DNA into the frog eggs to detect CO2.” [Reuters]
Here’s how they did it.
Step 1 — Get Some Frog Eggs
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We knew that bacteria could stink, but new research asks if bacteria can smell. A study published today argues that Bacillus licheniformis found in soil can sense ammonia given off by neighboring bacteria. Though we might turn our noses when we smell the gases given off by neighbors, the bacteria respond to ammonia by building a thick biofilm coating.
The research appears today in Biotechnology Journal. Previous studies have shown that bacteria can sense gases such as oxygen, but this is the first study to argue that bacteria can smell, since ammonia has a scent. Lead author Reindert Nijland explains that bacteria break the pungent gas down for its useful nitrogen, so an ammonia-detector and biofilm response might be a useful survival tool. He even suggests that this might be the earliest example of olfaction in evolutionary history.
“Ammonia is the simplest available nitrogen source,” Nijland said. “All organisms need nitrogen to produce their proteins.” The ammonia is thought to signal both the presence of nutrients and the presence of other bacteria, since the biofilms Bacillus species produce in response to ammonia contain antibiotics that can kill competing bacteria. And the ability to “smell” ammonia “gives bacteria a way to sense nutrients where nutrients are and then migrate towards them,” he said. [The Scientist]
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How can some sleepers doze through anything from the rattle of a jackhammer to the blast of a jet engine? According to a new study, an extra helping of brain activity in the thalamus–a region tied to the senses–may give some people a better chance at blocking sleep-disturbing sounds.
“I hear complaints a lot as a sleep doctor that noises are interrupting people’s sleep all the time,’’ said Dr. Jeffrey M. Ellenbogen, chief of the division of sleep medicine at Harvard Medical School [and co-author of the study]. “What is it in the brain that makes it have less response to noise at night, and how can we enhance that natural occurring brain-based process to help people sleep?” he said. [The New York Times]
Researchers at the Harvard Medical School asked twelve healthy volunteers to spend three nights in a sleep lab. The first night the researchers let them sleep soundly, but monitored their brain activity. The following two nights, they used four speakers aimed at the sleepers’ heads to play sounds of air and car traffic, ringing telephones, and “hospital-based mechanical sounds,” among other things. They found that those people whose thalami produced more high-frequency signals called “sleep spindles” lasted the longest when barraged with noises: the more sleep spindles, apparently, the better the sleep. The study appears today in Current Biology.
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Sure, the planet’s increasing carbon dioxide levels are making the oceans more acidic, but what does that really mean for sea life? We’ve already heard that the ocean’s changing chemistry is damaging corals and interfering with mussels, but that’s just the beginning. It turns out things could get seriously weird.
In a paper published this week in The Proceedings of the National Academy of Sciences, researchers led by Philip L. Munday of James Cook University have given us a concrete example: the increased CO2-levels make some fish purposely swim towards predators.
As part of his experiment, Munday used a Y-shaped maze to force baby clownfish to choose between two paths. One path reeked of rock cod, a natural predator; the other had no danger scents. Munday’s team compared the choices of fish raised in water of varying carbon dioxide concentrations, from today’s levels of 390 parts per million up to future expected levels of 850 ppm.
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Touch comes first. It’s the first way that people interact with the world, MIT’s Josh Ackerman says, and touch can change the way you feel about the world or engage with it.
Ackerman and colleagues published a study in Science this week further uncovering the ways that what we touch influences what we think. In a series of experiments, his team demonstrated numerous examples of the tactile altering the mental, like people negotiating more stubbornly when sitting in hard, uncomfortable chairs, or taking decisions more seriously when holding a weighty object like a clipboard.
The idea, then, is that due to the strong connection between our senses and our thoughts, touching a surface can trigger feelings related to the metaphorical value we assign to it. Or, more simply, the feeling of weight makes us feel like a decision is more “weighty,” a harsh surface like sandpaper leads to harsh feelings toward other people, and the touch of smoothness makes us feel like things are going to smooth over.
“The tactile sensation is extremely important early in development. The idea that other associations would be built on that makes intuitive sense,” said Franklin & Marshall College psychologist Michael Anderson, who was not involved in the study. “Brain regions that may initially have been dedicated to one particular task, turn out to contribute to multiple tasks” [Wired.com].
For more on this, check out Ed Yong’s in-depth post at Not Exactly Rocket Science.
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Image: Science/AAAS
When a person’s cornea is burned it’s not necessarily the splashed chemicals or hot liquids that causes blindness, but the eye’s recovery. Scar tissue, formed from cells in the white part of the eye, can cover the cornea in a cloudy haze. But researchers have found that cells drawn from another part of the body can correct the problem.
A paper published yesterday in the New England Journal of Medicine brings news of a regenerative stem cell treatment that has had striking success: It restored sight to 82 of 117 eyes with burnt corneas, and worked partially on 14 others. The treatment also seems to have a long-lasting impact; in one patient, the beneficial effect has lasted for ten years and counting.
The treatment offers hope to those who received little benefit from existing therapies–such as artificial cornea replacements, which can also be overpowered and clouded by white-colored cells, or stem cell or cornea transplants from cadavers, which patients can reject.
“[The patients] were incredibly happy. Some said it was a miracle,” said one of the study leaders, Graziella Pellegrini of the University of Modena’s Center for Regenerative Medicine in Italy. “It was not a miracle. It was simply a technique.” [AP]
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The weird phenomenon of blindsight—in which people take in visual information about objects without actually “seeing” them—has long intrigued scientists, and with good reason. They’ve watched people navigate obstacle courses and identify colors while being technically blind. This week, in a study in Nature, neuroscientists point to a part of the brain called the lateral geniculate nucleus (LGN) as the neural key that might make blindsight possible.
They used macaques in which the primary visual cortex had been destroyed. The monkeys’ eye-focusing movements revealed that they were “seeing” images shown at the periphery of their visual field, but only if their LGN was intact [New Scientist].
The authors refer to the LGN as the “main relay” between the retina and main visual cortex.
Other work had shown that the LGN also has projections to a number of secondary visual areas, suggesting that it may serve as a major hub in the visual system. To test this suggestion, the authors injected the LGN with a chemical that activates the receptor for a major inhibitory signaling molecule…. When the chemical is present, nerve cells receive a signal telling them to stop signaling, so this this injection has the effect of shutting the LGN down entirely [Ars Technica].
When the scientists shut down the LGN, the primates in the study didn’t experience any blindsight, as it appears no information was reaching any of their brains’ visual centers.
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It’s the essence of instinct: If you take a lab mouse who has never caught a glimpse of a cat and waft a little eau de feline towards it, the mouse will freeze in fear, and will then back away from the source of the odor. Now researchers have pinned down the chemical signals the mice are reacting to–and have shown in the process a fascinating new form of inter-species communication.
Mice have a specialized organ in their noses that picks up chemical signals, called the vomeronasal organ, which helps them detect pheromones emitted by other mice. These mice pheromones have a direct effect on behavior–most obviously in the realms of mating and fighting. In this new study, published in the journal Cell, neurobiologist Lisa Stowers decided to investigate whether the vomeronasal organ was capable of picking up signals from other species as well.
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In today’s edition of far-out science, researchers have found evidence that the wafting aroma of food has an effect on an organism’s lifespan–and they’ve demonstrated that interfering with a fruit fly’s sense of smell causes it to live a longer, healthier life. While there’s no guarantee that the trick would work for humans, optimistic researchers suggest that certain odors—or drugs that block us from sensing them—might one day help prevent disease and extend lives [ScienceNOW].
In the past decade, scientists have established a clear connection between extremely low-calorie diets and extended lifespans; studies have demonstrated that yeast, fruit flies, mice, and monkeys on these diets live longer than their peers. While the exact mechanism at work isn’t yet clear, researchers suspect that a near-starvation diet causes an organism’s metabolism to slow down, and triggers other changes that evolved to help organisms survive in times when food was scarce. Now scientists say it may not be just what a creature eats, but also what it smells that has an effect on how long it lives.
In one 2007 study, molecular biologist Scott Pletcher and his colleagues found that completely eliminating fruit flies’ sense of smell caused them to live nearly 20 percent longer than normal flies. They also found that wafting the smell of yeast, a tasty treat for fruit flies, towards flies that were on a low-cal, live-extending diet hastened the death of those flies. This led the scientist to hypothesize that specific odors might be influencing the flies’ lifespans. Luckily, other scientists had identified a receptor in a group of neurons that enable fruit flies to smell carbon dioxide, which signals the presence of a good meal of tasty yeast [ScienceNOW]. So, Pletcher and his team set out to find if the CO2 had anything to do with the duration of the flies’ lives.
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The invention of the microscope allowed scientists to peer into the tiniest of cells. Now, imagine a device that can not just look into minute cells, but can also listen in on their activities.
A team of scientists is building a “micro-ear” that uses tiny beads and lasers to amplify and measure vibrations on a molecular scale. The team hopes the new device will become standard lab equipment soon, allowing scientists to listen to the movement of bacteria such as E. coli as well as microorganisms that cause diseases like sleeping sickness [The Daily Beast].
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