The human-fruit fly connection

Researchers can remove a fly's brain and place it — still functioning — under a microscope. They can isolate neurons that have different functions and watch them fire -or send signals- to other neurons when stimulated.

VOA - M. Saner

A research associate at Davis' lab prepares the series of tubes for the flies' olfactory memory training.

Once they identify which neurons are firing differently in the normal flies that have learned to identify the difference, they examine the mutants that don't remember the shocking odor to see how genes control the firing process.

Fruit flies have essentially the same genes as we do, just fewer of them. Davis says that correlation is what makes his research so promising.

"If we find a gene in flies that's important for a process like memory formation, that sequence of that gene is generally conserved [across species]. We can use that gene to identify a similar gene in a mouse or in humans, because they have a very, very high sequence similarity. The bases that make up the gene are very similar." He explains that is how researchers are able to identify with a very high probability in humans the vast majority of genes that exist in fruit flies.

"We're actually quite similar to a fruit fly, believe it or not," he adds with a laugh.

VOA - M. Saner

Each vial in the storeroom can hold more than 150 flies.

Generations of flies in one room

Fruit flies have a very short lifespan compared to other laboratory animals like the mouse or rat. So, with the flies mating and reproducing every two weeks, many generations of flies can be studied in a year, allowing researchers to do genetic studies quickly. And since the flies are small, hundreds of thousands of them can be stored easily and inexpensively in plastic vials.

Davis shows off a small room at the Institute, filled with vials of fruit flies — all to be used in the search for answers to how our memories are made and stored.

"If one examines the vast majority of neurological diseases — Alzheimer's, Parkinson's and so forth, and psychiatric diseases — schizophrenia, bipolar disorder, ADHD, autism, all of these have a commonality in that they have learning disorders, in general, or memory formation seems to be an underlying feature of the vast majority of neurological and psychiatric diseases."

Davis and his team of researchers hope their work will lead to a drug that will help the brain fight learning- and memory-related diseases. He says gaining a fundamental understanding of how the learning process works could be the key to treating — and perhaps curing — them.

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Fruit Flies Could Unlock Mystery of Alzheimer's

Scientists look to insects for answers on how human brain forms and retains memories

Mary Saner | Jupiter, Florida 16 March 2010

Photo: Max xx, Flickr Creative Commons

The common fruit fly, Drosophila melanogaster, is one of the most commonly used research animals.

At Scripps Research Institute in Jupiter, Florida, scientists are working to find clues about how the human brain processes memories. Their laboratory test animal is not a chimp or a dog or a rat — animals that we know can remember things — it is the common fruit fly.

"They're relatively simple," Ron Davis says, explaining why the fruit fly's brain has some ideal properties for human brain research. "The brain of the fruit fly has about 100,000 neurons. The brain of a human has about 100 billion neurons, and that's an enormous network of interconnected neurons in the human brain, if one thinks about it. We literally can't wrap our brains around the human brain yet."

Fruit fly training regimen

Davis chairs the Department of Neuroscience at Scripps Florida. He's designed an experiment in which fruit flies are trained to remember an odor associated with an unpleasant electrical shock.

VOA - M. Saner

Dr. Ron Davis says fruit flies have essentially the same genes as humans do, just fewer of them.

It involves a series of Plexiglas tubes which have an electrifiable copper grid on their surfaces. "One puts the fly in these tubes first, passes an odor through the tube," Davis says. "Odor A shocks the animal, mild electric shock." After fresh air has been blown through the tubes to remove any trace of the first odor, a second scent is pumped in.

"Odor B passes through the tube and the animals are not shocked. That's the training where we're hoping the animals will develop an association. They'll learn that one odor is bad because it's been punished in the presence of that odor. And the other odor is okay."

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Study Questions Results of Clinical Trials That End Early

Carol Pearson | Washington 25 March 2010

The authors of the study say researchers need to resist pressures to end clinical trials early

From time to time, researchers stop clinical trials because the results seem almost too good to be true. A new international study shows that is probably because those results are not true.

When researchers end a clinical trial early because the results are better than expected, it allows a drug to get on the market and patients to receive it sooner than if the trial were carried out as planned.

It sounds like a good thing, but it may not be.

A new international analysis of 100 clinical trials that ended early found that the results were often wrong and sometimes life-threatening.

Dr. Victor Montori of the Mayo Clinic is one of the authors of the report. "What is happening is they are catching the data at a random high. The data is accumulating and it looks like a big effect, but if you let it go a little bit, that effect may become smaller over time," he explained.

Or, the benefit of the treatment may not even exist.

"Not only were the studies misleading, in terms of how big the treatment effect was really, but also whether a treatment effect existed at all," Dr. Montori said.

The clinical trials that Dr. Montori and his colleagues reviewed ended early because the results of an experimental treatment were much better than those of an existing therapy.

An example is a study on beta-blockers, drugs often prescribed for high blood pressure. Beta blockers slow the heart rate and can prevent heart attack during surgery. An initial trial was stopped early because these drugs looked to be highly effective if given prior to surgery. The drugs seemed to improve survival rates. But a larger trial showed that some patients given the drugs had significantly higher death rates.

Dr. Montori and other researchers compared the 100 trials that were called off early with more than 400 comparable trials that went through to completion. They found that the results were especially misleading in the smaller trials that ended early.

"What the investigators are caught on is when they look at the data at a given time before the study was supposed to finish, and they find a large treatment effect, then they get mislead by that treatment effect, and then in fact, if they decide to stop at that point, they end up misleading everyone else when they publish the results," he said.

Dr. Montori says the false findings discourage other researchers from repeating the study to see if they get the same positive results.

The authors of the study say researchers need to resist pressures to end clinical trials early. They say this will prevent patients and physicians from making treatment choices based on inaccurate information, or even worse, choosing one treatment when another would be far better.

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Researchers Develop Portable Desalination Device

Jessica Berman | Washington 25 March 2010

Photo: Credit: Sung Jae Kim/Jongyoon Han

A new energy-efficient desalination device, the size of a postage stamp, could be made into a portable desalination system operated by current battery technology

American and South Korean researchers have demonstrated a nano-technology based method for converting sea water into drinking water. So far, the invention only purifies tiny amounts of water, but scientists say the technology may someday be used in low-power facilities to remove salt and other contaminates.

The desalination process was tested on a postage stamp-size chip, which uses an electric current to help separate electrically charged salt particles and other impurities from water to make it drinkable.

Conventional, industrial-size desalination facilities use a process called reverse osmosis to filter salt and other contaminants out of sea water. But they are expensive to run and require a lot of power, which makes them a poor fit for many low-income countries, says Massachusetts Institute of Technology Biotechnology Professor Jongyoon Han. "Many of these countries that suffer from the water shortages also [do not] have the water delivery infrastructure, do not have electricity infrastructure to power these large scale plants. I think these are some of the combined challenges that we need to address," he said.

Han and his colleagues have developed ion concentration polarization, which improves the efficiency of the filtering process by adding a small electrical charge to the salt and other impurities.

The chip removed 99 percent of the salt and other contaminants from samples of undrinkable water.

Han says the technology might one day be available as a personal water purification appliance or used to bring drinking water to communities by scaling up the technology to create plates containing thousands of chips. "And then run all of these little devices at the same time to get the flow rate at the levels of perhaps a hundred milliliters per minute. That flow rate is the typical flow rate you can get from the household filtration devices," he said.

Han would like to develop a way to power the devices so they can bring water in the wake of natural disasters, such as this year's devastating earthquake in Haiti. "It needs to be run without the need for continuous power supply because some of these countries or disaster zones [do not] have working power or electricity. So, we think the power efficiency of this device is good enough so we can run this small unit with the solar power," he said.

Han describes the desalination-on-a-chip technology this week online in the journal Nature Nanotechnology.

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Australia Signs Mammoth Gas Deal With China

Phil Mercer | Sydney 25 March 2010

Australian officials say a $54 billion deal to sell liquefied natural gas to China shows that trade between the two countries remains on track. There had been concerns that tensions over China's arrest of executives of the Australian mining company Rio Tinto could derail relations. Phil Mercer reports from Sydney.

Canberra says the liquefied natural gas deal is proof that its economic relationship with China has not been damaged by the trial in Shanghai this week of Australian Rio Tinto executive Stern Hu.

Hu and three Chinese colleagues have been charged with briber and commercial spying. Their trial has ended but no verdicts have been handed down.

The arrest of the Rio Tinto employees created diplomatic friction between Canberra and Beijing.

However, Australian Resources and Energy Minister Martin Ferguson says the new LNG deal with China National Offshore Oil Corporation (CNOOC) shows that business ties have not been harmed.

"It's very clear that right through the difficulties over Stern Hu we have maintained a healthy business relationship with China that has been mutually beneficial to both countries. And the contract with CNOOC (China National Offshore Oil Corporation) a major player on the west coast of Australia, is also of significance because it now brings them to the east coast of Australia and it says loud and clear that from an energy and a resource point of view, Australia's very important to China's future economic development," said Ferguson.

The agreement is Australia's second major gas deal with the Chinese in six months.

The project will supply 72 million tons of LNG over 20 years. The gas is extracted from coal seams in central Queensland.

Queensland's state premier, Anna Bligh, says the LNG project will create up to 9,500 jobs.

The project is due to start in 2014, but must meet strict foreign investment and environmental regulations first.

China is Australia's biggest trading partner thanks mainly to its strong demand for iron ore, coal and liquefied natural gas. Exports to China helped Australia escape the worst effects of the global economic meltdown over the past two years.

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5 Soldiers, 21 Militants Die in Battle in Pakistan

VOA News 26 March 2010

Pakistan's army says five soldiers and at least 21 militants have been killed in a battle in the northwestern tribal region of Orakzai.

The army said militants attacked a post in the region early Friday, prompting security forces to retaliate.

The violence followed a series of air strikes that killed at least 50 people, most of them suspected militants, in Orakzai Thursday. Local officials said the attacks targeted sites including an Islamic seminary (madrassa) and a school used by the Taliban.

Many militants are believed to have fled to Orakzai to escape a military offensive farther south.

Also Thursday, law enforcement authorities in the central city of Jhelum announced the arrest of two suspects in the kidnapping of a 5-year-old British boy, snatched from his family earlier this month.

Investigators say the suspects are part of a criminal gang linked to other crimes, including murders and kidnappings.

Kidnappers abducted Sahil Saeed from his grandparents' house on March 4 as robbers held the family at gunpoint. He was released unharmed 12 days later, after his family paid kidnappers a ransom of about $150,000. Authorities say they recovered most of the money.

Police in Spain and France have already arrested five people in connection with the kidnapping, including two Pakistani men and a Romanian woman. Authorities say two of the suspects collected the ransom from the boy's father in Paris.

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Dozens Missing From Sunken South Korean Navy Vessel

Kurt Achin | Seoul 27 March 2010

Photo: AP

A South Korean coast guard ship, front, and a Naval ship patrol to rescue possible survivors from a sunken naval ship near South Korea's Baeknyeong Island, close to North Korea, 27 Mar 2010

South Korea is scrambling to locate at least 46 South Korean military personnel missing after a one of the South's naval patrol vessels sank in a tense maritime area disputed by North Korea. Seoul is investigating what caused the incident, but holding off for now on blaming the North.

South Korean officials say rescuing sailors remains their top priority. One hundred four South Korean navy personnel were on board the patrol ship in waters west of the Korean peninsula Friday night when it was apparently damaged by an explosion and sank.

South Korean President Lee Myung-bak called an emergency meeting of top security officials Saturday, for the second time in a 12-hour period. South Korean authorities say they are investigating "all possibilities" as to why the ship went down, including the scenario that the ship was attacked by North Korea.

The incident occurred near South Korea's Baekryoung island, next to what is called the Northern Limit Line - a maritime border drawn by the United Nations at the signing of an armistice that paused the 1950s Korean War.

North Korea has challenged the legitimacy of the border, and the two sides have fought at least three naval skirmishes in the area in the past 11 years.

Still, South Korean officials are downplaying the notion the ship was attacked by North Korea - in part, because the incident occurred southwest of Baekryoung island, deep in South Korean waters.

Carl Baker, a Korean security specialist and director of Pacific Forum CSIS in Honolulu, agrees a North Korean role seems unlikely.

"You know, it looks to me like it was a naval accident, an unfortunate naval accident, that happened. I mean, it just seems like it was an explosion on the ship. And I'm just kind of skeptical about it being a North Korean attack or something," said Baker.

Baker says the timing of such an attack would be strange, given recent reports of a possible upcoming visit to China by North Korean leader Kim Jong Il and the possible resumption of talks aimed at ending North Korea's nuclear weapons programs.

"If it is... a North Korean attack, it would signal something kind of strange that isn't consistent with all the other news going on at this point," said Baker.

North Korea is also seeking to relieve the pressure international sanctions has put on its sputtering economy - in part, by asking South Korea for a renewal of economic joint projects. Some analysts believe a military attack would contradict those efforts.

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