Tag Archives: science & technology

Animal eggs not a good source for embryonic stem cells: study

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A study published on Monday has found that eggs from cows, rabbits and other animals are not a good source for creating embryonic stem cells, the master material that could one day repair tissue damage, replace organs, and reverse degenerative diseases.

But, in the same study, US researchers made a significant advance in the cloning of human embryos, which could be a path to producing a host of patient-specific treatments.

“This study shows for the very first time that cloning really works and that DNA is reprogrammed,” said co-author Robert Lanza, the chief scientific officer at Advanced Cell Technology.

Lanza and his team were able to replace the nucleus of a number of embryos and bring the clones to the morula stage, where they had divided into eight to 16 cells.

In the human embryos, they were able to prove that the DNA was reprogrammed because the same genes were activated as in a normal embryo.

But something went wrong when the nuclei of rabbit, mice and cow embryos were replaced with a human nucleus.

“We would get these beautiful little embryos but it wouldn’t work: instead of turning on the right genes the animal eggs would turn them off,” Lanza told AFP. Researchers had hoped that cloned animal eggs could be used to create human embryonic stem cells, which are highly versatile, primitive cells capable of developing into any tissue of the body.

The dream is to coax these cells into becoming lab-dish replacements for heart, liver, skin, eye, brain, nerve and other cells destroyed by disease, accidents, war or normal wear-and-tear.

Scientists have found two potential ways to avoid the dangers of organ or tissue rejection.

The most promising method is to reprogram skin cells so they behave like

embryonic stem cells. But these “induced pluripotent stem cells” (iPS) are currently created using harmful viruses and are not safe for clinical use.

Cloning embryos so that they have the same DNA or tissue type as the patient could be safe for clinical use.

But researchers have not yet derived an embryonic stem cell line from a cloned embryo or found an efficient way to clone human embryos.

There had been hope that the animal eggs could be used as a substitute for human embryos, which are difficult to harvest and controversial to use. “This very important paper suggests that livestock oocytes (the cells from which eggs develop) are extremely unlikely to be suitable as recipients for use in human nuclear transfer,” said Ian Wilmut, director of the Centre for Regenerative Medicine in Edinburgh and editor-in-chief of Cloning and Stem Cells, which published the paper.

“This is very disappointing because it would mean that production of patient-specific stem cells by this means would be impracticable.”

Working with human embryos is also impractical because the high failure rate means it takes hundreds of eggs to create a single stem cell line, said Alan Trounson, president of the California Institute for Regenerative Medicine.

“Most people are working on IPS cells (stem cells derived from skin) rather than nuclear transfer because it’s so difficult to get human eggs,” Trounson said.

“Their work is endorsing that we could use human eggs but I don’t think it helps us, to be honest, in actually being able to do it because it doesn’t show that it could be improved dramatically.”

Trounson said human cloning can still be important in addressing some serious genetic diseases because it would allow for the manipulation of mitochondria, which run cell function and contain DNA.

But Lanza said it’s too soon to give up on embryonic stem cell research. “We need to continue research on both fronts because we don’t know if IPS cells or cloning will be better,” he said.

“It’s good to have a backup approach.”

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IBM computer will have power of 2 million laptops

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Seven months after IBM delivered the world’s fastest supercomputer, it has announced an even speedier one with the computing power of 2 million laptops.

IBM said on Tuesday it is developing the technology for its new Sequoia computer, with delivery scheduled in 2011 to the Department of Energy for use at Lawrence Livermore National Laboratory.

Sequoia will chug along at 20 petaflops per second and is one order of magnitude quicker than its predecessor. The earlier machine, delivered in June to the Energy Department, broke the 1 petaflop barrier.

Peta is a term for quadrillion and FLOP stands for floating point operations per second.

Sequoia, and a smaller computer called Dawn, are being built in Rochester, Minnesota, for use in simulating nuclear tests. IBM says they can also be used for complex tasks like weather forecasting or oil exploration.

IBM says Sequoia will be highly energy-efficient for the job it does but even so will occupy 96 refrigerator-sized racks in an area the size of a big house — 3,422 square feet (318 square meters).

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Long space stay makes bones weak

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Astronauts who spend months in space tend to lose bone strength, making them increasingly vulnerable to fractures in later life.

Universities of California (UC) Irvine and San Francisco evaluated 13 astronauts who spent four to six months on the International Space Station and found that, on an average, their hipbone strength decreased 14%.

Three astronauts experienced losses of 20% to 30%, rates comparable to those seen in older women with osteoporosis.

These results alarmed researchers because they revealed a greater rate of bone deterioration than previously measured using less powerful technologies.

Orthopaedic researchers looking into the effects of long-duration spaceflight usually study the hipbone or spine. The hip experiences the greatest rate of bone loss in space, and a hip fracture almost always requires hospitalisation and major surgery.

It can impair a person’s ability to walk unassisted and may cause prolonged or permanent disability or even death. Fractures of the vertebra also have serious consequences, including loss of height, severe back pain and deformity.

“If preventive measures are not taken, some of our astronauts may be at increased risk for age-related fractures decades after their missions,” said Joyce Keyak of UC Irvine, biomedical engineering professor, who led the study.

For as long as there have been astronauts, researchers have studied why the environment of space makes bones more fragile. While previous studies looked at bone mineral density, this study is the first to specifically evaluate bone strength.

Keyak and her colleagues used a novel computer programme she developed over the past 20 years to identify hipbone fracture risk in people with osteoporosis. The study team used this programme to analyse structurally the hipbone CT scans of one female and 12 male International Space Centre crewmembers, said an UCI release.

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Sorghum gene code could lead to drought-tolerant crops: study

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An international team of scientists reported on Wednesday it had laid bare the DNA code of sorghum, a hardy tropical cereal whose genes could one day be spliced to produce crops that resist global warming.

Sorghum (Latin name Sorghum bicolor) is related to sugar cane and corn and is grown in arid regions of northeast Africa, India and the southern United States for food, fibre, fuel and animal feed.

Sequencing of the sorghum genome adds to that in 2005 of the rice plant, the world’s most important food plant. Draft sequences of corn, also called maize, and soyabean were unveiled in 2008. Work is underway to sequence wheat, barley, as well as the tomato and potato.

The goal behind genomic sequencing is to find genes that can boost yields to help feed the world’s burgeoning population, or to enable the plant to survive harsh conditions inflicted by climate change.

These genes can then be introduced into other plants, using either traditional breeding techniques or genetic engineering, it is hoped.

The sorghum project, led by Andrew Paterson of the University of Georgia, is reported in this week’s issue of Nature, the British-based science journal.

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Exercise for just 7 min a week enough to stay fit

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Rigorous workouts lasting as little as three minutes may help prevent diabetes by helping control blood sugar, British researchers said on Wednesday.

The findings published in the journal BioMed Central Endocrine Disorders suggest that people unable to meet government guidelines calling for moderate to vigorous exercise several hours per week can still benefit from exercise. “This is such a brief amount of exercise you can do it without breaking a sweat,” said James Timmons, an exercise biologist at Heriot-Watt University in Edinburgh, who led the study.

“You can make just as big as an effect doing this as you can by doing hours and hours of endurance training each week.”

Timmons and his team showed that just seven minutes of exercise each week helped a group of 16 men in their twenties control their insulin. The volunteers, who were relatively out of shape but otherwise healthy, rode an exercise bike four times daily in 30 second spurts two days a week.

After two weeks, the men had a 23% improvement in how effectively their body used insulin to clear glucose from the blood stream, Timmons said. The effect appears to last up to 10 days after the last round of exercise, he added.

“The simple idea is if you are doing tense muscle contractions during sprints or exercise on a bike you really enhance insulin’s ability to clear glucose out of the bloodstream,” he said.

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Japanese researchers develop all-round flu vaccine

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Researchers in Japan said Thursday they had developed a flu vaccine that works against multiple viruses and could prevent a deadly pandemic of bird flu mutations.

The research team has tested the vaccine on mice implanted with human genes, confirming that it works even if flu viruses mutate, according to Tetsuya Uchida, researcher at the National Institute of Infectious Diseases.

Currently flu vaccines use a protein covering the surface of viruses but the protein frequently mutates to make the vaccines ineffective.

The newly developed vaccine is based on common types of protein inside the bodies of flu viruses as they rarely change, Uchida told AFP. The viruses used are the Soviet-A and Hongkong-A along with the deadly H5N1 strain of bird flu.

“We expect this will also be effective on new variations” of the much-feared H5N1 strain in addition to conventional flu viruses, he said.

The World Health Organisation (WHO) warns that millions of people could die worldwide if the avian influenza virus mutates into a form easily transmissible among humans.

Uchida said it would likely take several years to put the vaccine to practical use as the research team needs to confirm the vaccine’s safety with further experiments on mice and possibly larger animals before tests on humans.

The study is being jointly conducted by researchers from the national institute, Hokkaido University, Saitama Medical University and NOF Corp., a chemicals company based in Tokyo.

Similar vaccination studies on attacking the inside of the virus body rather than its surface are also under way abroad, including at Oxford University in Britain, Uchida said.

About 250 people have died of avian flu since 2003, according to the WHO.

Indonesia is the country worst-hit by avian influenza with 115 deaths officially recorded since 2003. Five people have fallen victim in China this year.

Human victims consist mostly of people in close contact with sick birds. There is no evidence so far that the deadly strain of bird flu has mutated into a form that could set off a pandemic.

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Researchers discover brain chemical makes locusts swarm

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Tickle a locust’s hind legs and two hours later it will be transformed into an insect ready to form a crop-devastating swarm.

While researchers know why — the tickling simulates the jostling that usually solitary locusts experience when limited food suppliers force them to crowd — they have puzzled for decades over how the radical biological transformation occurs.

A study released Thursday by the journal Science found that the brain chemical serotonin triggers the switch from aversion to attraction.

“Serotonin profoundly influences how we humans behave and interact, so to find that the same chemical in the brain is what causes a normally shy antisocial insect to gang up in huge groups is amazing,” said study co-author Swidbert Ott of Cambridge University.

The researchers discovered that locusts in swarm mode — called gregarious locusts — had serotonin levels three times higher than those in a solitary behavior phase.

Once in this phase, the green locusts turn bright yellow, gain large muscles that equip them for prolonged flight and actively seek the company of other locusts. They can develop into swarms of billions and fly 60 miles (96 km) in five to eight hours in search of food.

But when they were injected with serotonin-blocking chemicals, locusts still in their antisocial phase remained calm and did not transform into the swarm phase in response to the leg tickling or presence of a crowd.

And when the locusts were injected with chemicals that stimulated serotonin they were transformed into the swarm phase without the stimulus.

“Up until now, whilst we knew the stimuli that cause locusts’ amazing ‘Jekyll and Hyde’-style transformation, nobody had been able to identify the changes in the nervous system that turn antisocial locusts into monstrous swarms,” said study co-author Michael Anstey of University of Oxford.

“The question of how locusts transform their behavior in this way has puzzled scientists for almost 90 years, now we finally have the evidence to provide an answer.”

While the discovery “harbors considerable potential” for dealing with the harmful insects, it will not likely to a short-term pest control solution, said Paul Anthony Stevenson of Germany’s Leipzig University.

“To be effective, antiserotonin-like chemicals would need to be applied when the animals are solitary locusts and scarce targets in vast expanses of desert — about three locusts per 100 square meters (1,076 sq ft),” Stevenson wrote in an accompanying article.

“Current serotonergic drugs are not designed for passing through the insect cuticle and sheath encasing the nervous system, nor are they insect-selective, hence their use is ecologically unjustifiable.”

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Pakistan amongst top 5 highest SMS traffic

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Pakistan is among the top five countries with the highest Short Message Service (SMS) traffic processed over the festive season.

A total of 6.37 billion text messages were sent through their messaging systems across Asia Pacific over the 2008/2009 Christmas and New Year period.

The Philippines stood first among the five countries again leading the ranking with 2.36 billion messages, closely followed by Indonesia (1.193 billion), Malaysia (1.075 billion) and Pakistan (763 million).

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Japan airline in world first ‘camelina’ biofuel test flight

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Japan Airlines (JAL) on Friday carried out the world’s first successful test flight of a Boeing aeroplane run on biofuel made primarily of a non-food energy crop called camelina.

In a joint project with the United States’ Boeing and engine maker Pratt and Whitney, JAL — Asia’s largest carrier — conducted a demonstration flight of about 90 minutes.

One engine on the Boeing 747-300 aircraft, which took off from Tokyo’s Haneda airport, was powered by biofuel mixed with conventional kerosene jet oil, the company said.

“No modifications to the aircraft or engine were required for biofuel,” JAL said in a statement.

“Today is an extremely important day for Japan Airlines, for aviation, and for the environment,” said JAL president Haruka Nishimatsu. “The demonstration flight brings us ever closer to finding a greener alternative to traditional petroleum-based fuel.”

“When biofuels are produced in sufficient amounts to make them commercially viable, we hope to be one of the first airlines in the world to start powering our aircraft using them,” he said.

The biofuel used in the flight is “a mixture of three second-generation biofuel feedstocks” of camelina, jatropha and algae, the airline said.

“Second-generation feedstocks do not compete with natural food or water resources and do not contribute to deforestation practices,” the company said.

The JAL flight was Boeing’s fourth project using biofuel.

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Cutting down calories does not prolong life

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Cutting down on calories may reduce weight, but it does not necessarily increase one’s life span, warns an Indian American expert.

“Today there are a lot of very healthy people who look like skeletons…,” said Raj Sohal, professor at the University of Southern California’s (USC) School of Pharmacy.

He and Michael Forster of the University of North Texas Health Science Centre compared the life span and caloric intake of two genetically engineered strains of mice.

“The fat strain, known as C57BL/6, roughly doubles in weight over its adult life. That strain benefited from caloric restriction. The lean strain, DBA/2, does not become obese,” said Sohal.

However, caloric restriction did not extend the life of these mice, confirming previous work by Forster and Sohal.

“Our study questions the paradigm that caloric restriction is universally beneficial,” Sohal said. “Contrary to what is widely believed, caloric restriction does not extend (the) life span of all strains of mice.”

By measuring the animals’ metabolic rate, Sohal and his colleagues came to a deceptively simple conclusion: Caloric restriction is only useful when, as in the case of the obese mice, an animal eats more than it can burn off.

“Your energy expenditure and your energy intake should be in balance,” Sohal said. “It’s as simple as that. And how do you know that? By gain or loss of weight. The whole thing is very commonsensical.”

For humans of normal weight, Sohal strongly cautions against caloric restriction. In a 2003 study, he and Forster found that caloric restriction begun in older mice – both in DBA and leaner C57 individuals – actually shortened life span.

However, Sohal said that obese individuals are probably better off cutting calories than increasing their exercise to make up for over eating. Overly vigorous exercise can lead to injuries and long-term wear and tear, said a USC release.

In other words, it is better to skip the double cheeseburger than to turn up the treadmill after going on a binge. The results are scheduled for publication in the Journal of Nutrition.

Sohal, who received his Ph D in biology from Tulane University, is also the recipient of Irwing S Wright Award of Distinction by the American Federation for Aging Research and Lifetime Research Achievement Award by the American Aging Association.

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