Night blindness found in dogs for first time
New York:Dogs too can get afflicted with a form of night blindness seen in humans, researchers including one of Indian-origin have found for the first time, a discovery that may lead to a gene therapy for the disorder.
People with congenital stationary night blindness, or CSNB, have normal vision during the day but find it difficult or impossible to distinguish objects in low light. Researchers have for the first time found a form of CSNB in dogs. The discovery and subsequent hunt for the genetic mutation responsible may one day allow for the development of gene therapy to correct the dysfunction in people as well as dogs, researchers said.
The team included the University of Pennsylvania School of Veterinary Medicine’s Gautami Das, a postdoctoral researcher; Keiko Miyadera, an assistant professor of ophthalmology; and Gustavo Aguirre, professor of medical genetics and ophthalmology.
Their main collaborator was Mineo Kondo, a professor and chair of ophthalmology at Mie University Graduate School of Medicine in Tsu, Japan, from whom they found out about a unique population of beagles with night-vision problems. The dogs had been bred by a Japanese pharmaceutical company and displayed behaviours characteristic of night blindness.
“In bright light they can walk around and navigate easily, but in darkness they sort of freeze,” Aguirre said. The company enlisted the expertise of Kondo’s team, which confirmed that the condition was CSNB by using physiological measures of the dogs’ retinal function. All the affected dogs showed signs characteristic of CSNB, specifically a type known as Schubert-Bornschein complete CSNB, which is also seen in humans.
In this condition, there is a malfunction in the process by which signals are transmitted between the retina’s photoreceptor cells and bipolar cells. The Japanese researchers first evaluated the dogs’ pedigree to determine how the condition was inherited and found it was an autosomal recessive disease; in other words, a dog needs two copies of the mutated gene in order to be affected. This process also allowed the scientists to see which of the dogs was a carrier for the disease.
The gene responsible for these dogs’ condition remains a mystery, but the researchers believe a genome-wide approach by means of whole-genome sequencing will narrow their hunt. “It could be that the mutation is in a regulatory region of the unidentified gene, such as within an intron or the promoter,” Das said.
Once they find it, they can begin development of a gene therapy approach to treating the condition, a strategy found successful by Aguirre’s group multiple times in dogs. This could find application in humans as well. The study was published in the journal PLOS ONE. (PTI)
NASA probe spots ‘global’ ocean on Saturn’s moon
Washington: A ‘global’ ocean containing a vast liquid water reservoir lies beneath the icy crust of Saturn’s geologically active moon Enceladus, according to new research using data from NASA’s Cassini mission.
Researchers found the magnitude of the moon’s very slight wobble, as it orbits Saturn, can only be accounted for if its outer ice shell is not frozen solid to its interior, meaning a global ocean must be present.
The finding implies the fine spray of water vapour, icy particles and simple organic molecules Cassini has observed coming from fractures near the moon’s south pole is being fed by this vast liquid water reservoir.
Previous analysis of Cassini data suggested the presence of a lens-shaped body of water, or sea, underlying the moon’s south polar region.
However, gravity data collected during the spacecraft’s several close passes over the south polar region lent support to the possibility the sea might be global.
The new results – derived using an independent line of evidence based on Cassini’s images – confirm this to be the case.
“This was a hard problem that required years of observations, and calculations involving a diverse collection of disciplines, but we are confident we finally got it right,” said Peter Thomas, a Cassini imaging team member at Cornell University, New York, and lead author of the paper. Cassini scientists analysed more than seven years’ worth of images of Enceladus taken by the spacecraft, which has been orbiting Saturn since mid-2004.
They carefully mapped the positions of features on Enceladus – mostly craters – across hundreds of images, in order to measure changes in the moon’s rotation with extreme precision. As a result, they found Enceladus has a tiny, but measurable wobble as it orbits Saturn.
Because the icy moon is not perfectly spherical – and because it goes slightly faster and slower during different portions of its orbit around Saturn – the giant planet subtly rocks Enceladus back and forth as it rotates.
The team plugged their measurement of the wobble, called a libration, into different models for how Enceladus might be arranged on the inside, including ones in which the moon was frozen from surface to core.
“If the surface and core were rigidly connected, the core would provide so much dead weight the wobble would be far smaller than we observe it to be,” said Matthew Tiscareno, a Cassini participating scientist at the SETI Institute, Mountain View, California, and a co-author of the paper.
“This proves that there must be a global layer of liquid separating the surface from the core,” said Tiscareno. The mechanisms that might have prevented Enceladus’ ocean from freezing remain a mystery.
Thomas and colleagues suggest the possibility that tidal forces due to Saturn’s gravity could be generating much more heat within Enceladus than previously thought. The research was published in the journal Icarus. (PTI)
Twitter offers new cash stream for presidential candidates
Washington:The social media service Twitter on Wednesday introduced a feature that enables political candidates and advocacy groups to raise money directly via its mobile application, making it quicker and easier to harvest small donations from followers.
Campaigns already aggressively use Twitter to spread their message, particularly during live political events such as Wednesday night’s Republican presidential debate. The company says that tweets about the August 6 debates on Fox News were viewed more than 1 billion times on Twitter and across the web.
And in a race likely to cost more than the USD 2 billion spent in 2012, why not look for cash in every corner? At least a dozen presidential candidates will begin using the new fundraising technique right away, said Jenna Golden, Twitter’s director of political ad sales. While the White House seekers are early adopters, Golden said the fundraising service is also available to local and state-level candidates.
Political candidates have been able to raise money through Twitter by linking to the web-based online donation forms. But for people on mobile devices and that’s 80 percent of Twitter’s audience it can be clunky to click through different applications and web pages.
Twitter is working with Square Inc., a financial services company, to collect the money and the information that the Federal Election Commission requires from political donors.
Would-be givers fill in their identifying information and link to a debit card.
A couple of clicks later, the Twitter user’s contribution is headed straight for the candidate of their choice, and they can “share” news of their financial support to their own Twitter followers. The candidates also can pay Twitter to promote their fundraising-linked tweets. (AP)