Newt Finding Might Set Back Efforts to Regrow Human Limbs: Scientific American

Unique proteins in these amphibians cast doubt on the existence of any latent potential for limb regeneration

By Zoe Cormier and Nature magazine


The Eastern, or red-spotted, newt may have evolved the ability to regenerate organs and limbs in relatively recent times Image: Flickr/StoneHorse Studios

The ability of some animals to regenerate tissue is generally considered to be an ancient quality of all multicellular animals. A genetic analysis of newts, however, now suggests that it evolved much more recently.

Tiny and delicate it may be, but the red spotted newt (Notophthalmus viridescens) has tissue-engineering skills that far surpass the most advanced biotechnology labs. The newt can regenerate lost tissue, including heart muscle, components of its central nervous system and even the lens of its eye.

Doctors hope that this skill relies on a basic genetic program that is common — albeit often in latent form — to all animals, including mammals, so that they can harness it in regenerative medicine. Mice, for instance, are able to generate new heart cells after myocardial injury.

The newt study, by Thomas Braun at the Max Planck Institute for Heart and Lung Research in Bad Nauheim, Germany, and his colleagues, suggest that it might not be so simple.

Attempts to analyze the genetics of newts in the same way as for humans, mice and flies have so far been hampered by the enormous size of the newt genome, which is ten times larger than our own. Braun and his colleagues therefore looked at the RNA produced when genes are expressed — known as the transcriptome — and used three analytical techniques to compile their data.

The team compiled the first catalogue of all the RNA transcripts expressed in N. viridescens, looking at both primary and regenerated tissue in the heart, limbs and eyes of both embryos and larvae.

The researchers found more than 120,000 RNA transcripts, of which they estimate 15,000 code for proteins. Of those, 826 were unique to the newt. What is more, several of those sequences were expressed at different levels in regenerated tissue than in primary tissue. Their results are published in Genome Biology.

Modern or ancestral?
The findings add to existing evidence that the ability evolved recently, says Jeremy Brockes of University College London, whose research provided the first evidence that regenerating tissue in salamanders express proteins that are not found in other vertebrates.

“I no longer believe that there is an ancestral program that is waiting to be reawakened,” Brockes says. “However, I absolutely do believe it’s possible to coax mammal tissues into regenerating to a greater degree with the lessons we learn from newts.”

But saying that the trait is either ancestral or recent is probably too “black and white”, says Elly Tanaka of the Center for Regenerative Therapies in Dresden, Germany. The truth, she says, could be somewhere in the middle. “It may in fact be that regeneration is ancestral, but that newts have species-specific adaptations that allow it to have such spectacular regenerative capacities compared with other vertebrates.”

Moreover, Tanaka adds, scientists would do well to look for more grey zones in the potential for harnessing the regenerative capacities of newts (and of other animals, such as fish). Rather than focusing on spectacular, but perhaps unlikely, scenarios in which amputees could regrow entire limbs, researchers should instead focus on more plausible options, such as improving the healing of scars and burns or increasing the speed of organ regeneration.

This article is reproduced with permission from the magazine Nature. The article was first published on February 21, 2013.


Life has been discovered beneath the Antarctic ice

Robert T. Gonzalez

There is life in Lake Whillans. For millions of years, this small body of liquid water has lurked hundreds of meters below Antarctica’s Ross Ice Shelf, sealed off from the outside world and the scientists who would explore its subglacial depths. Now, in a monumental first, a team of researchers led by Montana State University glaciologist John Priscu has bored a tunnel to Whillans and encountered life, making Priscu and his colleagues the first people in history to discover living organisms in the alien lakes at the bottom of the world.

I say “alien” because Lake Whillans — like the hundreds of other subglacial lakes and waterways entombed beneath Antarctica’s assorted ice shelves — is thought to harbor conditions similar to those of Jupiter’s moon Europa and Saturn’s moon Enceladus . Hundreds of meters below the surface of Earth’s southernmost continent, pressures soar to vitality-crushing levels. Nutrient availability is minimal. Sunlight is nonexistent. Antarctica’s bygone repositories of liquid water have been isolated from the rest of the world for so long, under conditions so extreme, that evidence of life in any of the continent’s subsurface reservoirs would bode well for our chances of discovering life on other worlds — to say nothing of the enormous boon such a discovery would be to biological research here on Earth.

Now, it appears we have that evidence.

“Lake Whillans definitely harbors life,” said Priscu in a phone interview with Nature News’s Quirin Schiermeier. “It appears that there lies a large wetland ecosystem under Antarctica’s ice sheet, with an active microbiology.”

Pictured above is the tunnel that Priscu and his colleagues had to drill in order to break through to the lake’s surface last month, on the 28th of January. “What they found,” writes Schiermeier, “was a body of water just 2 metres or so deep – much shallower than the 10–25 metres seismic surveys had suggested, although Priscu notes that the lake may well have deeper spots.”

Schiermeier continues:

The team put a camera down the borehole to make sure that the borehole was wide enough for sampling instruments to be deployed and returned safely. It was, and over the next few days, the scientists collected some 30 litres of liquid lake water and eight sediment cores from the lake’s bottom, each 60 centimetres long.

What precious stuff they had retrieved soon became clear under the on-site microscope. Both water and sediment contained an array of microbes that did not need sunlight to survive. The scientists counted about 1,000 bacteria per millilitre of lake water – roughly one-tenth the abundance of microbes in the oceans. In Petri dishes, the bacteria show a “really good growth rate”, says Priscu.

Photographs like the one featured below, captured by cameras at the bottom of Lake Whillans, can’t tell us much of anything about the genetic makeup of these microbes. That being said, the hypothesis that these organisms will represent some heretofore undescribed extremophiles, uniquely suited to their punishing local environment, is not an unreasonable one; and it’s a hypothesis which, if confirmed, could make for some very intriguing lines of genetic investigation.

To that end, Priscu says he and his team will have to rely on DNA sequencing and other tests, preliminary rounds of which will take at least a month to perform. Followup studies will surely extend out for years to come.

“What we are all dying to find out now is, of course, ‘who’s there’ and ‘what’s their life style’,” he says.

Aren’t we all.

Read more at Nature News and at links provided throughout the post. For more on the hunt to explore Antarctica’s subglacial lakes, start by visiting here and here ; Lake Whillams may be the first of Antarctica’s subsurface pools to exhibit an active microbiology, but it’s far from the first to have its surface breached.
Photos by Alberto Behar, JPL/ASUM

Adorable Pygmy Chameleon Captured in Stunning Photos – News Watch

As the sun went down over the southernmost extension of the Great African Rift Valley, Harvard University entomologist and renowned wildlife photographer Piotr Naskrecki began hiking up Mozambique’s Mount Gorongosa . Lured by the chorus of katydids, Naskrecki left the group of biologists he had traveled to Africa with behind and followed the sounds of the cryptic insects into the unknown alone. With his headlamp on and three days worth of supplies stuffed into his backpack, he began his search for the small insects in the forest ahead. But what he found was not what he set out to see…

At the edge of the rainforest near the top of the 6,112-foot mountain, Naskrecki spotted an animal whose shape seemed both unexpected and oddly familiar. Recalling the event Naskrecki said, “it took my brain a second to pull together disparate threads of superficial knowledge and then… Sweet Merciful Jeebus, this is the Gorongosa Pygmy Chameleon!”

Gorongosa Pygmy Chameleon ©Piotr Naskrecki 2013

The Gorongosa Pygmy Chameleon (Rhampholeaon gorongosae) was first discovered in 1971. Since its discovery, it has only been spotted by a handful of people. Naskrecki explained that he had encountered pygmy chameleons before when he was spending time in Madagascar, but had only ever read about the nearly mythical Gorongosa Pygmy Chameleon.

Unlike their larger relatives (Chamaeleoninae), which have prehensile tails and live high on trees and bushes, Gorongosa Pygmy Chameleons lack a prehensile tail and spend most of their lives closer to the ground in the leaf litter. Naskrecki explained that it is only at night that these small lizards climb up branches, like the one he first saw, to avoid being eaten by shrews and other nocturnal predators found in the area.

“Since few night predators are equipped with good color vision, at night they [Gorongosa Pygmy Chameleons] shrink their color-producing chromatophores in their skin, and turn ghostly pale,” Naskrecki stated. “This of course makes them easy to spot by somebody carrying a powerful flashlight, and soon I started noticing dozens of them sleeping on trees and bushes all around me.”

Under the new moon, Naskrecki headed back to his tent after his rare sighting dreaming of the upcoming day, which he planned to spend photographing the tiny lizards. However, when Naskrecki woke with the sun the next morning, the pygmy chameleons were nowhere to be found.

Abandoning the katydids that he originally set out to find, Naskrecki spent the entire day searching for the lizards whose small size and ability to alter their body color and pattern to match the forest floor make them difficult, if not impossible, to find. But his search was in vain.

It wasn’t until the sun sank below the horizon that Naskrecki saw the tiny lizards again. With the darkness of night the pygmy chameleons turned ghostly white and appeared on the branches, making them easy to see as he scanned the forest vegetation with his headlamp; however, the lack of light prevented him from photographing the tiny creatures.

Determined to document a day in the life of the Gorongosa Pygmy Chameleon, Naskrecki woke up before the sun the following day, emerging from his tent just in time to spot one last chameleon slowly climbing down the branch it had been hugging the night before.

As the tiny lizard skillfully descended to the forest floor, Naskrecki noticed a newly hatched baby nearby. Focused on the larger female, he didn’t notice as the baby made its way over to the larger female and climbed on top of her to hitch a ride. Though, once it happened, he did capture the endearing and rare scene in incredible images.

Gorongosa Pygmy Chameleon

As the day passed, Naskrecki followed the little lizards’ tiny steps, photographing them as they slowly climbed over dead leaves and skillfully caught grasshoppers, termites and other small insects with their incredibly long tongues.

Gorongosa Pygmy Chameleon

“During the few nights that I spent on the mountain, in those moments when I wasn’t giggling with delight at the sight of the most adorable lizard on the planet, I found several katydid species new to science,” Naskrecki said after returning from his solo expedition into the largely unknown jungle atop Mount Gorongosa.

Talking to Naskrecki back at Harvard, it is obvious that while he traveled to Gorongosa National Park to help survey the biodiversity of the area, which is still largely unknown and just beginning to be studied, he left with much more than a list of animals he had seen and a handful of new species to describe. He got to witness the unique and mysterious creatures that call Gorongosa National Park home and through his photography and research he is dedicated to sharing these tiny wonders with the rest of the world.

Click through the gallery below to see photos taken by Naskrecki of the Mount Gorongosa Pygmy Chameleon. To find out more about Gorongosa National Park and the Gorongosa Pygmy Chameleon visit their website .

Gorongosa Pygmy Chameleon

Piotr Naskrecki in Gorongosa National Park

Gorongosa Pygmy Chameleon

Gorongosa Pygmy Chameleon

Gorongosa Pygmy Chameleon

©Piotr Naskrecki 2013

Antarctic lake beneath the ice sheet tested

An artist’s representation of the aquatic system scientists believe is buried beneath the Antarctic ice sheet. (Credit: Zina Deretsky, NSF)

Jan. 29, 2013 — In a first-of-its-kind feat of science and engineering, a National Science Foundation (NSF)-funded research team has successfully drilled through 800 meters (2,600 feet) of Antarctic ice to reach a subglacial lake and retrieve water and sediment samples that have been isolated from direct contact with the atmosphere for many thousands of years.

Scientists and drillers with the interdisciplinary Whillans Ice Stream Subglacial Access Research Drilling project (WISSARD) announced Jan. 28 local time (U.S. stations in Antarctica keep New Zealand time) that they had used a customized clean hot-water drill to directly obtain samples from the waters and sediments of subglacial Lake Whillans.

The samples may contain microscopic life that has evolved uniquely to survive in conditions of extreme cold and lack of light and nutrients. Studying the samples may help scientists understand not only how life can survive in other extreme ecosystems on Earth, but also on other icy worlds in our solar system.

The WISSARD teams’ accomplishment, the researchers said, “hails a new era in polar science, opening a window for future interdisciplinary science in one of Earth’s last unexplored frontiers.”

A massive ice sheet, almost two miles thick in places, covers more than 95 percent of the Antarctic continent. Only in recent decades have airborne and satellite radar and other mapping technologies revealed that a vast, subglacial system of rivers and lakes exists under the ice sheet. Lakes vary in size, with the largest being Vostok Subglacial Lake in the Antarctic interior that is comparable in size to Lake Ontario.

WISSARD targeted a smaller lake (1.2 square miles in area), where several lakes appear linked to each other and may drain to the ocean, as the first project to obtain clean, intact samples of water and sediments from a subglacial lake.

The achievement is the culmination of more than a decade of international and national planning and 3 1/2 years of project preparation by the WISSARD consortium of U.S. universities and two international contributors. There are 13 WISSARD principal investigators representing eight different U.S. institutions.

NSF, which manages the United States Antarctic Program, provided over $10 million in grants as part of NSF’s International Polar Year portfolio to support the WISSARD science and development of related technologies.

The National Aeronautics and Space Administration’s (NASA) Cryospheric Sciences Program, the National Oceanic and Atmospheric Administration (NOAA), and the private Gordon and Betty Moore Foundation also provided support for the project.

The interdisciplinary research team includes groups of experts in the following areas of science: life in icy environments, led by John Priscu, of Montana State University; glacial geology, led by Ross Powell, of Northern Illinois University; and glacial hydrology, led by Slawek Tulaczyk, of the University of California, Santa Cruz.

Sharing of expertise by the groups of disciplinary experts will allow the data collected to be cast in a systemic, global context.

The WISSARD team will now process the water and sediment samples they have collected in hopes of answering seminal questions related to the structure and function of subglacial microbial life, climate history and contemporary ice-sheet dynamics.

Video surveys of the lake floor and measurements of selected physical and chemical properties of the waters and sediments will allow the team to further characterize the lake and its environs.

The approach to drilling was guided by recommendations in the 2007 National Research Council-sponsored report, “Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship,” aimed to protect these unique environments from contamination.

A team of engineers and technicians directed by Frank Rack, of the University of Nebraska-Lincoln, designed, developed and fabricated the specialized hot-water drill that was fitted with a filtration and germicidal UV system to prevent contamination of the subglacial environment and to recover clean samples for microbial analyses. In addition, the numerous customized scientific samplers and instruments used for this project were also carefully cleaned before being lowered into the borehole through the ice and into the lake.

Following their successful retrieval, the samples are now being carefully prepared for their shipment off the ice and back to laboratories for numerous chemical and biological analyses over the coming weeks and months.

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“Fantastic” New Flying Frog Found—Has Flappy Forearms

Helen’s flying frog uses webbed feet to glide through Vietnamese forests.

Photograph courtesy Jodi Rowley

Christine Dell’Amore

National Geographic News

Published January 14, 2013

Scientists have stumbled across a new species of flying frog—on the ground.

While hiking a lowland forest in 2009, not far from Ho Chi Minh City (map), Vietnam , “we came across a huge green frog, sitting on a log,” said Jodi Rowley , an amphibian biologist at the Australian Museum in Sydney and lead author of a new study on the frog.

Rowley later discovered that the 3.5-inch-long (9-centimeter-long) creature is a relatively large new type of flying frog, a group known for its ability to “parachute” from tree to tree thanks to special aerodynamic adaptations, such as webbed feet, Rowley said. (Also see “‘Vampire Flying Frog’ Found; Tadpoles Have Black Fangs.” )

Rowley dubbed the new species Helen’s flying frog, in honor of her mother, Helen Rowley, “who has steadfastly supported her only child trekking through the forests of Southeast Asia in search of frogs,” according to a statement.

The newfound species—there are 80 types of flying frogs—is also “one of the most flying frogs of the flying frogs,” Rowley said, “in that it’s got huge hands and feet that are webbed all the way to the toepad.”

“Females even have flappy skin on their forearms to glide,” added Rowley, who has received funding from the National Geographic Committee on Research and Exploration . (National Geographic News is part of the National Geographic Society.) “The females are larger and heavier than males, so the little extra flaps probably don’t make much of a difference,” she said.

As Rowley wrote on her blog , “At first it may seem strange that such a fantastic and obvious frog could escape discovery until now—less than 100 kilometers [60 miles] from an urban centre with over nine million people.”

Yet these tree dwellers can easily escape notice—they spend most of their time in the canopy, she said.

Flying Frog on the Edge

Even so, Helen’s flying frog won’t be able to hide from development near Ho Chi Minh City, which may encroach on its existing habitats.

So far, only five individuals have been found in two patches of lowland forest hemmed in by rice paddies in southern Vietnam, Rowley said. The animals can probably tolerate a little bit of disturbance as long as they have large trees and temporary pools, she added.

But lowland forests are among the most threatened habitats in the world, mostly because they’re so accessible to people, and thus chosen for logging and development. (Get the facts on deforestation .)

“While Helen’s flying frog has only just been discovered by biologists,” Rowley wrote, “unfortunately this species, like many others, is under great threat from ongoing habitat loss and degradation.”

The new flying frog study was published in December 2012 in the Journal of Herpetology .

Origin of Photosynthesis Revealed

Schematic of Cyanophora paradoxa. (Credit: Courtesy of Bhattacharya Lab.)

Atmospheric oxygen really took off on our planet about 2.4 billion years ago during the Great Oxygenation Event. At this key juncture of our planet’s evolution, species had either to learn to cope with this poison that was produced by photosynthesizing cyanobacteria or they went extinct. It now seems strange to think that the gas that sustains much of modern life had such a distasteful beginning.

So how and when did the ability to produce oxygen by harnessing sunlight enter the eukaryotic domain, that includes humans, plants, and most recognizable, multicellular life forms? One of the fundamental steps in the evolution of our planet was the development of photosynthesis in eukaryotes through the process of endosymbiosis.

This crucial step forward occurred about 1.6 billion years ago when a single-celled protist captured and retained a formerly free-living cyanobacterium. This process, termed primary endosymbiosis, gave rise to the plastid, which is the specialized compartment where photosynthesis takes place in cells. Endosymbiosis is now a well substantiated theory that explains how cells gained their great complexity and was made famous most recently by the work of the late biologist Lynn Margulis, best known for her theory on the origin of eukaryotic organelles.

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“Virgin Birth” Record Broken by Hotel Shark

A wild zebra shark swims off Thailand (file picture).   Photograph by Rodger Klein, Getty Images

Charles Choi

for National Geographic News

Published January 6, 2012

She may be confined to a desert hotel, and far from any males, but a zebra shark named Zebedee is record-breakingly fertile.

The female shark, which lives in a restaurant aquarium in Dubai‘s Burj Al Arab, has experienced four straight years of “virgin births”—a feat never before documented among sharks, according to marine biologist David Robinson.

(Related: “Shark ‘Virgin Birth’ Confirmed.”)

Experts at the resort—billed as the world’s most luxurious—had seen Zebedee lay eggs before, but had assumed they held no offspring, because she is never in the presence of any male zebra sharks. Hotel staff first discovered she was reproducing asexually in 2007.

“We were actually moving the eggs, and one of the guys felt something move inside the egg, and we checked the eggs with light, and there were babies inside,” Robinson, assistant aquarium operations manager at the Burj Al Arab, told the BBC.

“We went looking for it, but I don’t think we were ever expecting to find it,” he said. “So we’re just awestruck.”

(See a picture of the Burj Al Arab surrounded by lightning.)

Virgin Birth Not So Rare in Sharks?

Zebedee is reproducing parthenogenetically, meaning that embryos are developing from eggs unfertilized by male sperm. Although her offspring are genetically very similar to her, they aren’t identical clones, since her DNA is recombined during the reproductive process.

Virgin births are known among many invertebrates and a variety of vertebrates, including hammerhead, blacktip, and bamboo sharks. (See “Hammerhead Shark Gave Virgin Birth in Omaha Zoo.”)

“Everyone’s looking for it in sharks now, and I think it’s always there to be found,” said marine biologist Demian Chapman of Stony Brook University in New York State.

“Since a very wide range of sharks can do it, I think it’s reasonable to speculate that all sharks can do this.”

(Related: “Virgin Birth Expected at Christmas—By Komodo Dragon.”)

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