Teperdexrian

The Interesting, The Strange, The News.

Archive for the ‘Biology’ Category

Genetically engineered mosquitoes pass lethal gene to offspring

leave a comment »

  • 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

Advertisements

12 new species of frogs discovered in India

leave a comment »

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

The mystery creature that nobody can identify

leave a comment »

If this cute little chap looks a wee bit confused, it’s no wonder.

His big wide eyes stare out at the world around him – which in turn is staring back at him.

Because nobody has seen a creature quite like this one before.

Who am I? The unidentifed animal sitting in his cage after being handed in to Wenling Zoo, in China

Who am I? The unidentifed animal sitting in his cage after being handed in to Wenling Zoo, in China.

With a nose that looks more like a rodent’s but long, pointy paws and white fur dappled with brown and orange, he is quite unique.

And zookeepers at Wenling, in eastern China, who were handed the animal by an anonymous man, have been unable to work out exactly what species he belongs to.

They think they are looking at some strange type of monkey – but other students of nature might recognise the characteristics of a bush baby.

As he sits in his cage, the creature therefore awaits an uncertain fate.

And the zookeepers sit and monitor his development and hopes he grows up into something slightly more recognisable.

Where did I come from? The rodent-like creature was handed in anonymously

Where did I come from? The rodent-like creature was handed in anonymously.

Via DailyMail

Written by Nokgiir

September 26, 2011 at 1:47 am

Immune System Trained to Kill Cancer

leave a comment »

 

A year ago, when chemotherapy stopped working against his leukemia, William Ludwig signed up to be the first patient treated in a bold experiment at the University of Pennsylvania. Mr. Ludwig, then 65, a retired corrections officer from Bridgeton, N.J., felt his life draining away and thought he had nothing to lose.

Doctors removed a billion of his T-cells — a type of white blood cell that fights viruses andtumors — and gave them new genes that would program the cells to attack his cancer. Then the altered cells were dripped back into Mr. Ludwig’s veins.

At first, nothing happened. But after 10 days, hell broke loose in his hospital room. He began shaking with chills. His temperature shot up. Hisblood pressure shot down. He became so ill that doctors moved him into intensive care and warned that he might die. His family gathered at the hospital, fearing the worst.

A few weeks later, the fevers were gone. And so was the leukemia.

There was no trace of it anywhere — no leukemic cells in his blood or bone marrow, no more bulging lymph nodes on his CT scan. His doctors calculated that the treatment had killed off two pounds of cancer cells.

A year later, Mr. Ludwig is still in complete remission. Before, there were days when he could barely get out of bed; now, he plays golf and does yard work.

“I have my life back,” he said.

Mr. Ludwig’s doctors have not claimed that he is cured — it is too soon to tell — nor have they declared victory over leukemia on the basis of this experiment, which involved only three patients. The research, they say, has far to go; the treatment is still experimental, not available outside of studies.

But scientists say the treatment that helped Mr. Ludwig, described recently in The New England Journal of Medicine and Science Translational Medicine, may signify a turning point in the long struggle to develop effective gene therapies against cancer. And not just for leukemia patients: other cancers may also be vulnerable to this novel approach — which employs a disabled form of H.I.V.-1, the virus that causes AIDS, to carry cancer-fighting genes into the patients’ T-cells. In essence, the team is using gene therapy to accomplish something that researchers have hoped to do for decades: train a person’s own immune system to kill cancer cells.

Two other patients have undergone the experimental treatment. One had a partial remission: his disease lessened but did not go away completely. Another had a complete remission. All three had had advanced chronic lymphocytic leukemia and had run out of chemotherapy options. Usually, the only hope for a remission in such cases is a bone-marrow transplant, but these patients were not candidates for it.

Dr. Carl June, who led the research and directs translational medicine in the Abramson Cancer Center at the University of Pennsylvania, said that the results stunned even him and his colleagues, Dr. David L. Porter, Bruce Levine and Michael Kalos. They had hoped to see some benefit but had not dared dream of complete, prolonged remissions. Indeed, when Mr. Ludwig began running fevers, the doctors did not realize at first that it was a sign that his T-cells were engaged in a furious battle with his cancer.

Other experts in the field said the results were a major advance.

“It’s great work,” said Dr. Walter J. Urba of the Providence Cancer Center and Earle A. Chiles Research Institute in Portland, Ore. He called the patients’ recoveries remarkable, exciting and significant. “I feel very positive about this new technology. Conceptually, it’s very, very big.”

Dr. Urba said he thought the approach would ultimately be used against other types of cancer as well as leukemia and lymphoma. But he cautioned, “For patients today, we’re not there yet.” And he added the usual scientific caveat: To be considered valid, the results must be repeated in more patients, and by other research teams.

Dr. June called the techniques “a harvest of the information from the molecular biology revolution over the past two decades.”

Hitting a Genetic Jackpot

To make T-cells search out and destroy cancer, researchers must equip them to do several tasks: recognize the cancer, attack it, multiply, and live on inside the patient. A number of research groups have been trying to do this, but the T-cells they engineered could not accomplish all the tasks. As a result, the cells’ ability to fight tumors has generally been temporary.

The University of Pennsylvania team seems to have hit all the targets at once. Inside the patients, the T-cells modified by the researchers multiplied to 1,000 to 10,000 times the number infused, wiped out the cancer and then gradually diminished, leaving a population of “memory” cells that can quickly proliferate again if needed.

The researchers said they were not sure which parts of their strategy made it work — special cell-culturing techniques, the use of H.I.V.-1 to carry new genes into the T-cells, or the particular pieces of DNA that they selected to reprogram the T-cells.

The concept of doctoring T-cells genetically was first developed in the 1980s by Dr. Zelig Eshhar at the Weizmann Institute of Science in Rehovot, Israel. It involves adding gene sequences from different sources to enable the T-cells to produce what researchers call chimeric antigen receptors, or CARs — protein complexes that transform the cells into, in Dr. June’s words, “serial killers.”

 

Read More Here

‘Lost’ rainbow toad rediscovered

leave a comment »

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

A step closer to explaining our existence

leave a comment »

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

Biological gems found in Philippines

leave a comment »

 Click through a slideshow featuring the new species.

Researchers say they identified 300 species that they think are new to science this spring during a biological prospecting expedition to the Philippines, organized by the California Academy of Sciences.

“The Philippines is one of the hottest of the hotspots for diverse and threatened life on Earth,” Terrence Gosliner, dean of science and research collections at the California Academy of Sciences and leader of the 2011 Philippine Biodiversity Expedition, said today in a news release about the findings. “Despite this designation, however, the biodiversity here is still relatively unknown, and we found new species during nearly every dive and hike as we surveyed the country’s reefs, rainforests, and the ocean floor.”

The 42-day expedition was launched in late April and focused on Luzon, the largest island in the Philippine archipelago, as well as the surrounding waters. In cooperation with more than two dozen colleagues from the Philippines, the academy’s scientists surveyed a wide range of ecosystems and shared their findings with local communities and conservationists.

Among the suspected new species are dozens of types of insects and spiders, deep-sea corals, sea pens, sea urchins and more than 50 kinds of sea slugs. Scientists say they came across a new kind of cicada that makes a distinctive “laughing” call, a starfish that eats only sunken driftwood, and a deep-sea swell shark that sucks water into its stomach to bulk up and scare off predators.

When the expedition ended, the scientists combined their data and identified their top conservation priorities — expansion of marine protected areas, plus reforestation to reduce sedimentation damage to coral reefs. The academy said reduction of plastic waste was also a priority, because plastic litter was pervasive throughout the marine environment, even on the ocean floor at depths of more than 6,000 feet.

Over the coming months, the expedition’s scientists will be analyzing their specimens with the aid of microscopes and DNA sequencing equipment to confirm their discoveries.

The academy’s expedition is one of many efforts around the globe to document and safeguard biodiversity — in part because yet-to-be-discovered species may point the way to commercially useful drugs or technologies, in part because they may turn out to be key to an ecosystem’s health, and in part because they’re beautiful, exotic or just plain odd.

“The species lists and distribution maps that we created during this expedition will help to inform future conservation decisions and ensure that this remarkable biodiversity is afforded the best possible chance of survival,” Gosliner said.

 

Via MSNBC/Alan Boyle