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Posts Tagged ‘nature

Genetically engineered mosquitoes pass lethal gene to offspring

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  • Scientists carry out ‘positive’ trial on Cayman Islands
  • New breed of insect could be used to tackle malaria and dengue fever
  • But critics say it could lead to public health problems

Breakthrough or danger? A UK-based research team has found a way of genetically modifying the Aedes aegypti mosquito so they pass on a deadly gene to their offspring

Breakthrough or danger? A UK-based research team has found a way of genetically modifying the Aedes aegypti mosquito so they pass on a deadly gene to their offspring

Serious concerns have been raised over the release of a new breed of disease-fighting mosquito which has been genetically engineered to kill their own offspring.

There are hopes the project could be used to control agricultural pests and tackle deadly insect-borne illnesses such as dengue fever and malaria.

But the research has raised concerns about the possible side-effects on public health and the environment because, once released, the mosquitos cannot be recalled.

A UK-based scientific team revealed there had been positive signs from the first release into the environment of the mosquitoes, which are engineered to pass a lethal gene onto their offspring, killing them before adulthood.

The study team – which includes experts from Imperial College London and the Liverpool School of Tropical Medicine – released batches of modified mosquitoes in an area of the Cayman Islands where the dengue virus-carrying Aedes aegypti mosquito is common.

The study, published in Nature Biotechnology journal, looked at how successfully the lab-reared, genetically modified insects could mate.

About 19,000 mosquitoes engineered in a lab were released over four weeks in 2009 in a 25-acre area on Grand Cayman island.

Based on data from traps, the genetically engineered males accounted for 16per cent of the overall male population in the test zone, and the lethal gene was found in almost 10 percent of larvae.

Those figures suggest the genetically engineered males were about half as successful in mating as wild ones, a rate sufficient to suppress the population.

Disease fighter? The new breed of mosquitoes could be used to tackle killer illnesses like dengue fever and malaria which affect the world's poorest populations

Disease fighter?  The new breed of mosquitoes could be used to tackle killer illnesses like dengue fever and malaria which affect the world’s poorest populations

Luke Alphey, chief scientific officer at Oxitec, the firm which devised the technique, told the BBC: ‘We were really surprised how well they did.

‘For this method, you just need to get a reasonable proportion of the females to mate with GM males – you’ll never get the males as competitive as the wild ones, but they don’t have to be, they just have to be reasonably good.’

HOW MOSQUITOES KILL THEIR OWN CHILDREN

  • The genetic approach used to create the mosquitoes is a system known as tetracycline-controlled transcriptional activation (tTA).
  • The technique is an extension of one successfully used for decades to control or eradicate pests which involves sterilising millions of insects with radiation.
  • But the process has not worked with mosquitoes, partly because the radiation also injures them, making it difficult for them to compete with healthy counterparts for mates.
  • So Oxitec has now created the Aedes aegypti mosquitoes with a gene that will kill them unless they are given the common antibiotic tetracycline.
  • With tetracycline provided in the lab, the mosquitoes can be bred for generations and multiplied.
  • Males are then released into the wild, where tetracycline is not available.
  • They live long enough to mate but their progeny will die before adulthood.

 

Authorities in the Florida Keys hope to carry out an open-air test on the modified insects as early as December after experiencing the region’s first cases of dengue fever in decades.

Dr Alphey said the technique was safe because only males were released as it was only the females that bite people and spread the disease.

But critics say the process is by no means foolproof.

Alfred Handler, a geneticist at the Agriculture Department in Gainesville, Florida, said the mosquitoes can evolve resistance to the lethal gene while being bred for generations in a lab.

Todd Shelly, an entomologist for the Agriculture Department in Hawaii, also said in a commentary published on Sunday by Nature Biotechnology that 3.5per cent of the insects in a lab test survived to adulthood despite presumably carrying the lethal gene.

Also, the sorting of male and female mosquitoes, which is done by hand, can result in up to 0.5per cent of the released insects being female, the commentary said.

If millions of mosquitoes were released, even that small percentage of females could lead to a temporary increase in disease spread, it was reported by the New York Times.

Oxitec and a molecular biologist, Anthony A. James of the University of California, Irvine, say they have developed a solution — a genetic modification that makes female mosquitoes, but not males, unable to fly.

The grounded females cannot mate or bite people, and separating males from females before release would be easier.

The World Health Organisation expects to release guidance on how GM insects should be deployed in developing countries by the end of the year.

 

Via DailyMail

12 new species of frogs discovered in India

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Scientists have found 12 new species of night frogs living in the lush mountains of southwest India, and rediscovered three that had been thought extinct.

Evolution biologist Sathyabhama Das Biju from the University of Delhi says he hopes the discoveries draw attention to amphibians as important indicators of environmental health.

He said Saturday that there are now 336 known frog species in India, and that many are threatened by habitat loss.

Night frogs are hard to find as they come out only after dark and during the monsoon season. Biju and student researchers had to sit in dark tropical forests listening for frog sounds and shining flashlights under rocks and across riverbeds.

The research is published in the latest issue of international taxonomy journal Zootaxa.

 

Via DiscoveryOn

Written by Nokgiir

September 26, 2011 at 2:19 am

‘Lost’ rainbow toad rediscovered

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Conservationists report that the Sambas Stream toad, one of their top 10 “lost” amphibian species, has been rediscovered in Malaysian Borneo 87 years after it was last sighted.

The find was made by scientists from Universiti Malaysia Sarawak who spent months looking for the toad in the remote Gunung Penrissen mountains of Western Sarawak, a natural boundary between Malaysia’s Sarawak State and Indonesia’s Kalimantan Barat Province on the island of Borneo. (Just writing those names makes me feel like Indiana Jones.)

Conservation International reports that the initial search was fruitless — so the expedition team, led by Indraneil Das, moved up to higher elevations and resumed the hunt. Eventually there came a night when one of Das’ graduate students, Pui Yong Min, spotted a small toad sitting 6 feet (2 meters) up a tree.

Das could hardly believe what he was seeing.

Indraneil Das

This picture of an adult female explains why it’s called a Bornean Rainbow Toad. The amphibian measures about 2 inches (51 millimeters) in size.

“Thrilling discoveries like this beautiful toad, and the critical importance of amphibians to healthy ecosystems, are what fuel us to keep searching for lost species,” Das said in a news release from Conservation International.  “They remind us that nature still holds precious secrets that we are still uncovering, which is why targeted protection and conservation is so important. Amphibians are indicators of environmental health, with direct implications for human health. Their benefits to people should not be underestimated.”

That’s the whole idea behind the “Search for Lost Frogs” campaign, which was launched a year ago by Conservation International and the International Union for Conservation of Nature’s SSC Amphibian Specialist Group. The groups drew up a “Ten Most Wanted” list in hopes of inspiring researchers to intensify the search for amphibians that have not been seen for decades.

The Sambas Stream toad is also known as the Bornean rainbow toad, with the scientific name Ansonia latidisca. The long-legged, multicolored toad was described by European explorers in the 1920s, and was last seen in 1924. Das’ team identified three individuals — an adult female, an adult male and a juvenile, ranging in size from roughly an inch to 2 inches (30 to 51 millimeters).

Each of the toads was found in a different mature tree, in a region of the Penrissen range that’s outside Sarawak’s system of protected areas. The precise location is being kept secret in hopes of keeping pet collectors from going after the rainbow toads.

The toads are listed as endangered on the IUCN Red List, and Conservation International said they may be eligible for protection under Sarawak’s wildlife ordinances.

Conservation International’s Robin Moore, an expert on amphibians, said he was amazed to hear of the discovery.

“When I saw an email with the subject ‘Ansonia latidisca found’ pop into my in-box, I could barely believe my eyes,” he said in the CI announcement. “Attached was an image — proof in the form of the first-ever photograph of the colorful and gangly tree-dwelling toad. The species was transformed in my mind from a black-and-white illustration to a living, colorful creature.”

Moore said he considered it a privilege to be among the first to see the pictures of the toad.

“It is good to know that nature can surprise us when we are close to giving up hope, especially amidst our planet’s escalating extinction crisis,” he said. “Amphibians are at the forefront of this tragedy, so I hope that these unique species serve as flagships for conservation, inspiring pride and hope by Malaysians and people everywhere.”

The rainbow frog is the second of the “Ten Most Wanted” amphibians to be rediscovered. The first was the Rio Pescado stubfoot toad (Atelopus balios), a species native to Ecuador that is critically endangered.

Two down, eight to go … the search continues.

 

Via MSNBC

Amazing photos capture split-second movements of animals leaping and flying… in a single frame

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Observing cats landing on their feet and squirrels scurrying around a garden might seem like just an ordinary event, but one talented photographer has transformed these moments into artwork.

The animal loving photographer has gone to extraordinary lengths to capture birds, rodents and insects in motion.

Using a special photographic technique that catches everything from the beat of a bird’s wing to the flick of a squirrel’s tail as it leaps through the air, Kim Taylor’s stunning photos of an animal’s ability to move from one place to another, also known as locomotion, is shown in awesome detail.

Incredible insects: A cockchafer beetle, otherwise called a may bug or spang beetle, is shot flying around the garden

Incredible insects: A cockchafer beetle, otherwise called a may bug or spang beetle, is captured flying around the garden.

Playful cats: Photographer Kim Taylor captures a white cat, named Pyramus, leaping from a chair onto a table, taken at 50 millisecond intervals

Poetry in motion: Photographer Kim Taylor captures a white cat, named Pyramus, leaping from a chair onto a table, taken at 50 millisecond intervals.

 With special homemade equipment, the 78-year-old from Surrey was able to capture his subjects in fractions of a second, giving a stunning ‘strobe’ effect on camera.

A rapidly-flashing light or strobe produces multiple images of a moving subject on a single photographic frame is a technique that has been around since the very early days of photography.

Legendary English photographer Eadweard Muybridge used this system to show the action of a galloping horse in the 1870s.

Mr Taylor was inspired to capture animals in motion by fellow Brit photographer Stephen Dalton who experimented with the technique in order to capture insects in flight.

Landing owl: A beautiful white and beige owl lands is pictured landing on a wooden post in a Surrey garden

Landing owl: A beautiful white and brown owl iis pictured landing on a wooden post in a Surrey garden.

Fluttering feathers: A European robin takes off from a wooden post as the sun sets in Surrey

Fluttering feathers: A European robin takes off from a wooden post as the sun sets in Surrey.

He said ‘I didn’t have any special equipment at the time so I had to design and build a special unit for the job.

‘This required generating dangerously high voltage – 3,500 volts – and storing the energy in a bank of special and very heavy capacitors.

‘The resulting equipment has three flash heads that flash simultaneously and produce nine flashes at rates varying from 2 per second to 500 per second.’

Playful pony: A Welsh pony and her rider a photographed galloping around some stables at half second intervals

Playful pony: A Welsh pony and her rider are photographed galloping at half second intervals.

Scurrying squirrel: A grey squirrel is captured leaping around the garden using eight images taken at 40 millisecond intervals

Leaping squirrel: A grey squirrel is captured jumping from branch to branch using eight images taken at 40 millisecond intervals.

Talented photographer: Kim Taylor from Surrey poses with his equipment Before turning to photography, Mr Taylorworked as a biologist with the Ministry of Overseas Development and later with the Ministry of Agriculture.

He received no formal training in photography or electronics but was able to learn most of what he needed to perfect his works by trial and error.

Kim said: ‘You can’t afford too many errors when dealing with a lethally high voltage, however, I am still here.

‘Because it’s very heavy, the unit does not often get taken on location, so most of the shots have been done in my Surrey garden.

‘Some of my early shots were of garden birds taking off and I had to make sure the timing was precise – just 25 to 35 milliseconds between flashes was necessary to ensure that the images were sufficiently separated.

‘I used further timing unit to ensure that the bird was already beginning to take off by the time the first strobe flash fired.

‘The shot of the robin at take off is one of my favourites but I also like the shots of insects in flight since they show how the wings are used to propel the insect into the air.

‘Digital photography and computerisation now allow series of images to be put together as if they represent a single event, whereas in reality, each image represents a separate event.

‘But genuine strobe photography shows one event as it really happened.’ Kim’s pictures are so innovative that the BBC’s One Show commissioned the photos of the squirrel which will be used on the programme this summer.’

 

Via DailyMail

African volcano spied from space

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Robert Simmon, using EO-1 ALI data

The Nabro volcano has been erupting in the African nation of Eritrea since June 13. This image made with data from a NASA satellite is giving scientists one of their most detailed views of the remote, little-studied volcano.

A NASA satellite captured this spectacular false-color image of the Nabro volcano erupting in a remote region of the northeastern African country of Eritrea.

The bright red portions of the image indicate hot surfaces, NASA explains in an advisory. That’s why the hot volcanic ash spewing out of the volcano’s caldera glows red.

To the west of the ash cloud, portions of the lava flow are visible. The front edge is particularly hot, thus red. The speckled bits upstream in the lava flow are likely regions where the cool, hardened crust is splitting and exposing fluid lava as the flow advances.

The volcano is located in an isolated region of Eritrea near its border with Ethiopia. Scientists believe it began erupting on June 13. Ash from the volcano has disrupted flightsand cut short Secretary of State Hilary Clinton’s recent trip to Africa.

Despite these impacts, scientists say they know very little about the volcano. When it was first detected, in fact, scientists thought it was the nearby Dubbi volcano. Imagery such as this photo from NASA’s Earth Observing-1 satellite acquired on June 24 is providing the most detailed look at the eruption to date.

 

Via MSNBC

Microbe could make biofuels hot

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A 94°C geothermal pool, with a level-maintaining siphon, near Gerlach, Nevada. Sediment from the floor of this pool was enriched on pulverized miscanthus at 90°C and subsequently transferred to filter paper in order to isolate microbes able to subsist on cellulose alone.

A record-breaking microbe that thrives while munching plant material at near boiling temperatures has been discovered in a Nevada hot spring, researchers announced in a study published today.

Scientists are eyeing the microbe’s enzyme responsible for breaking down cellulose — called a cellulase — as a potential workhouse in the production of biofuels and other industrial processes.

Cellulose is a chain of linked sugar molecules that makes up the woody fiber of plants. To produce biofuels, enzymes are required to breakdown cellulose into its constituent sugars so that yeasts can then ferment them into the type of alcohol that makes cars (not people) go vroom.

At the industrial scale, this process is done most efficiently at high temperatures that kill other microbes that could otherwise contaminate the reaction, Douglas Clark, a chemical and biomolecular engineer at the University of California at Berkeley, told me today.

“So finding cellulases that can operate at those temperatures are of interest,” he said.

Hot spring
That’s what led Clark, microbiologist Frank Robb from the University of Maryland, and colleagues to collect sediment and water samples from the Great Boiling Springs near Gerlach, Nevada. The spring is 203 degrees F, just short of boiling.

“It’s on private land and has been surrounded by a low wall to keep cattle from going into it and that maintains the temperature,” Robb explained to me today, noting that most hot springs have varying temperatures depending on the weather and water levels in the spring.

In addition, a siphon has been added to Gerlach hot spring to keep it from overflowing. The combination gives whatever microbes that are in there no choice but to grow at high temperatures, Robb noted. Bits of grass and woody material blown into the spring serve as a food source.

The team grew microbes found in the samples on pulverized miscanthus, a type of grass that is a common biofuel feedstock, to isolate the microbes that grow with plant fiber as their only source of carbon.

They then sequenced the community of surviving microbes, which indicated three species of Archaea, a type of single celled microorganism, were able to utilize cellulose as food. Genetic techniques identified the specific cellulase involved in the breakdown of cellulose.

This cellulase, dubbed EBI-244, was found in the most abundant of the three Archaea.

“We didn’t really expect to find an organism that could grow at such a high temperature and degrade cellulose in this particular environment. But you never know,” Clark told me. “It really underscores the diversity of life. And, obviously, if you don’t look, you won’t find it.”

Too hot
The enzyme EBI-244 works optimally at 228 degrees F (109 degrees C), which is actually too hot for the efficient breakdown of cellulose into fermentable sugars due to side reactions that can occur, Clark noted.

“But it is interesting to know that such cellulases are out there,” Clark said. “And then this cellulase might also serve as a good starting point to be engineered to work at a lower temperature but maintain the high stability that it has naturally evolved to work at such high temperatures.”

Robb likened this engineering process to building a street car from parts used on cars found at the racetrack. “The enzyme itself could be the parts bin,” he said.

So, the enzyme itself probably won’t be hard at work anytime soon producing fuel to put in your gas tank, but it does lead researchers down the road to engineering the biofuels of the future. What’s more, EBI-244 is a record holder for heat tolerance in cellulase.

“It is always nice to have a record breaker,” Clark noted. “It adds to that wow factor a little bit.”

 

Via MSNBC

A step closer to explaining our existence

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Fred Ullrich / Fermilab

Confidence is growing in results from a particle physics experiment at the Tevatron collider that may help explain why the universe is full of matter.

Why are we here? It remains one of the largest unexplained mysteries of the universe, but particle physicists are gaining more confidence in a result from an atom smashing experiment that could be a step toward providing an answer.

We exist because the universe is full of matter and not the opposite, so-called antimatter. When the Big Bang occurred, equal parts of both should have been created and immediately annihilated each other, leaving nothing leftover to build the stars, planets and us.

Thankfully, it didn’t happen that way. There’s an asymmetry between matter and antimatter. Why this is remains inadequately explained, Stefan Soldner-Rembold, a co-spokesman for the particle physics experiment at the Fermi National Accelerator Laboratory  outside of Chicago, told me on Thursday.

“We are looking for a larger asymmetry than we currently know in the best theories in physics, which is called the standard model,” said Soldner-Rembold, who is based at the University of Manchester in England.

Using the Fermilab’s Tevatron collider, members of the DZero experiment are smashing together protons and their antiparticle, called antiprotons, which are perfectly symmetric in terms of matter and antimatter, he explained.

“So you expect what comes out will also be symmetric in terms of matter and antimatter,” he said. “But what we observe is that there is a slight, on the order of 1 percent, asymmetry where more matter particles are produced than antiparticles.”

This 1 percent asymmetry is larger than predicted by the standard model and thus helps explain why there is more matter than antimatter in the universe.

The DZero team announced this finding of asymmetry in 2010, but their confidence in the result wasn’t sufficient to call it a discovery. At that point, there was a 0.07 chance the result was due to a random fluctuation in the data.

The team has now analyzed 1.5 times more data with a refined technique, increasing their confidence in the result. The probability that the asymmetry is due to a random fluctuation is now just 0.005 percent. They’d like to get to an uncertainty of less than 0.00005 percent before popping open the champagne.

The new results were presented Thursday at Fermilab.

“There are very high thresholds in physics so that people can really call something a discovery and be absolutely sure,” Soldner-Rembold said. “We are going in the right direction.”

Even more work at Fermilab and further, complementary experiments with the Large Hadron Collider in Geneva will be required to shore up confidence that what they are seeing really is real, and thus a step toward explaining why the universe has much more matter than antimatter.

“To really understand how the universe evolved is the next step,” he said. “We do a particular process in the lab. In order to say is this enough to explain the amount of matter around us is not as easy as saying 1 percent sounds good.”

And for those hoping that science has all the answers, Soldner-Rembold cautions that science will never answer the question of “why we are here, it only tries to understand the underlying laws of nature.”

 

Via MSNBC/John Roach