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Molecule critical for immune function identified

Tue, 08 Jul 2008 10:45:00 -0400

A new study has revealed that body''s immune system depend on a single molecule, a growth factor, without which it cannot function.

The study led by Dr Cecile King and PhD student Alexis Vogelzang, from the Garvan Institute of Medical Research in Sydney

Human body produces B cells, which make antibodies, and T cells, which help them but the way in which these cells operate and interact with each other are still being studied.

Previous studies had identified a subset of T cells, T follicular helper (TFH) cells that operates in specific environments termed ''germinal centres'', specialised areas within lymph organs where B cells proliferate to form high affinity antibodies whenever we fight infection.

TFH cells play a critical role in that they communicate with, and help activate, B cells.

The researchers found a molecule interleukin 21 (IL-21) is a growth factor for TFH cells.

IL-2''s newly identified growth factor role is only one of several functions, that function is fundamental. Without IL-21, the all-important TFH cells could neither develop nor survive.

"We already knew that IL-21 was produced by TFH cells and that it was a major initiator of proliferation in B cells," said King.

"We were surprised to find that TFH cells not only produce IL-21, they also absolutely need it to survive and they utilise it to function."

"We showed that if you take a mouse genetically deficient in IL-21 and immunise it, you don''t get TFH cells and you don''t get antibody production. Conversely, if you put IL-21 receptor sufficient, or normal, T cells into the same mouse, where of course the B cells remain abnormal, you recover the normal immune reaction."

"These specialised T cells are thought to be the ones that direct traffic. They are the only ones that can move into the B cell zone and initiate high affinity antibody production."

"Without IL-21, we probably wouldn''t be completely immunodeficient, just severely compromised. In addition to the high affinity antibodies we''re talking about, our bodies also produce a lot of low affinity antibodies for mopping up infection. That low level response happens around-the-clock and is one of our body''s first lines of defence."

"You could say that IL-21 directs the most finely-tuned aspect of our immune response. The highly specialised weaponry developed on-the-spot to target aggressive invaders."

"This finding suggests novel ways to boost vaccination or natural defences," she added.

The study was published online today in the prestigious international journal Immunity. (ANI)

New find may help prevent yellow fever mosquitoes from breeding

Tue, 08 Jul 2008 10:43:00 -0400

Researchers at North Carolina State University have discovered why pregnant yellow fever mosquitoes (Aedes aegypti), one of the most important disease transmitters worldwide choose certain places to lay their eggs - a find that may be important to stop them from breeding.

They found that certain chemicals emanating from bacteria in water containers stimulate the female mosquitoes to lay their eggs.

The female mosquitoes sense these chemical cues and decide that the water container is a preferable environment for their larvae to develop.

Lead authors, Dr. Charles Apperson and Dr. Coby Schal, professors of entomology at NC State, said that the findings could have implications for devising lures and traps that might help control yellow fever mosquito populations in equatorial locations around the globe, which would go a long way toward preventing important global diseases like dengue fever and yellow fever.

During the study, researchers found that yellow fever mosquitoes are particularly motivated to lay eggs in water containers that have just the right amounts of specific fatty acids associated with bacteria involved in the degradation of leaves and other organic matter in water.

The chemicals associated with the microbial stew are far more stimulating to discerning female mosquitoes than plain water, for example, or filtered water in which the bacteria once lived.

The study used a combination of approaches, including one in which the researchers presented female mosquitoes with different types of bacteria and bacterial extracts, and figured out "what turned the mosquitoes on" to lay their eggs.

"Some water-filled containers are rejected by the female mosquito. If we filter the bacteria out, the mosquitoes want no part of the water container. But put the filtered bacteria back in the water container, and the mosquitoes will be stimulated to lay eggs," Apperson said.

Female mosquitoes are choosy when it comes to finding the proper egg-laying habitats. They do not normally lay all their eggs in one location, but instead exhibit a behaviour called "skip-oviposition," distributing eggs in multiple water-filled containers.

Once the researchers discerned the specific chemical compounds that stimulated increased egg laying - a blend of fatty acids and methyl esters - they exposed the mosquitoes to varied concentrations of the chemical brew.

High concentrations of the brew gave the mosquitoes pause, causing them to withhold their eggs.

Lower concentrations were more convincing to mosquitoes than high concentrations, but still not as convincing as the proper amount - found to be only 10 nanograms in 30 millilitres of water.

The researchers said that mosquito larvae depend on microbes in their new homes for growth and development, so it is important for mothers to be discerning when it comes to living arrangements for their young.

Now, the researchers hope to use this choosiness against female mosquitoes.

According to researchers, stimulating females to lay eggs in water containers that have lethal chemicals or insect growth regulators could be another tool in the overall strategy kit to control mosquitoes - and dreaded diseases like dengue fever.

"We want to use the mosquito''s egg-laying behaviour against itself for control purposes," Apperson said.

The study is published in Proceedings of the National Academy of Sciences. (ANI)

Sex in space is inevitable, say experts

Tue, 08 Jul 2008 10:42:00 -0400

With US agency NASA and several other countries planning more and more space missions, scientists have started to debate on the possibility of cosmic sex.

Though nobody claims to know whether it has already happened, some experts believe that sex in space is inevitable.

Jason Kring of Embry-Riddle Aeronautical University in Florida, who studies the psychological effects of long-duration space missions, is just not ready to accept that astronauts cannot have sexual feelings while on a three-year mission to Mars.

"To say that astronauts are some superior beings who cannot have interests in any kind of sexual feelings for three years ... I just don''''t buy it," Live Science quoted him as saying.

The report also highlighted the fact that space agencies were gradually inclining towards sending more and more mixed crews of men and women in space, with studies suggesting that they are better at performing the tasks assigned to them.

"They''''re mission-oriented. They''''re very focused on the task at hand," said NASA spokesperson Nicole Cloutier-Lemasters of the Johnson Space Center.

Kring, however, said that sexual frustration could ensue.

"Human sexuality is a basic need and now you''''re trying to tell people, ''''Hey for three years, you can''''t do that.'''' They''''re going to figure out a way to do it," he said.

Lawrence Palinkas, a professor of social work, anthropology and preventive medicine at UCLA, pointed out that there was "no official policy" at NASA regarding sex on space missions.

"There really has been no research conducted on the area to know whether it (sex in space) would be a good thing or a bad thing, but it probably is inevitable," he said.

Science journalist Laura Woodmansee, the writer of ‘Sex in Space’ that was published in 2006, predicts "honeymoons in space and out-of-this-world sex will be a reality within a decade."

The book describes several positions that might work during cosmic copulation, ranging from the modified missionary position to seated with "interlocking Y legs".

She writes that props also could come into play, including a shared elastic waistband or tethers to hold one partner to a stable structure. (ANI)

Half of US coral reefs in ''poor'' or ''fair'' condition, says NOAA report

Tue, 08 Jul 2008 10:41:00 -0400

Almost 50 percent of U.S. coral reef ecosystems are in ‘poor’ or ‘fair’ condition, according to the National Oceanic and Atmospheric Administration (NOAA) report.

The report has revealed that the nation''s coral reef ecosystems, particularly those adjacent to populated areas, continue to face intense human-derived threats from coastal development, fishing, sedimentation and recreational use.

Even the most remote reefs are subject to threats such as marine debris, illegal fishing and climate-related effects of coral bleaching, disease and ocean acidification, according to the report.

"NOAA''s coral program has made some significant progress since it was established 10 years ago, but we need to redouble our efforts to protect this critical resource," said retired Navy Vice Admiral Conrad C. Lautenbacher Jr., Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator.

Tim Keeney, deputy assistant secretary of commerce for oceans and atmosphere and co-chair of the United States Coral Reef Task Force, said: "The report shows that this is a global issue.”

"While the report indicates reefs in general are healthier in the Pacific than the Atlantic, even remote reefs are subject to threats stemming from climate change as well as illegal fishing and marine debris," he added.

According to the report’s authors, the conditions of U.S. coral reefs have been declining for several decades.

As an indicator of this decline, since the last status report was released in 2005, two coral species - Elkhorn and Staghorn corals - have become the first corals ever listed as threatened under the Endangered Species Act.

The 2008 report is the third in a series, representing an evolving effort to track the condition of coral reef ecosystems at both local and national scales.

The 569-page document details coral reef conditions in the U.S. Virgin Islands, Puerto Rico, Navassa Island, southeast Florida, the Florida Keys, Flower Garden Banks, the Main Hawaiian Islands, the Northwestern Hawaiian Islands, American Samoa, the Pacific Remote Islands, the Republic of the Marshall Islands, the Federated States of Micronesia, the Commonwealth of the Northern Mariana Islands, Guam and the Republic of Palau.

The report was released by NOAA at the 11th International Coral Reef Symposium in Fort Lauderdale, Fla. (ANI)

Scientists use 3-D data across coastal seascapes to study climate effects on young fish

Tue, 08 Jul 2008 10:39:00 -0400

Washington, July 8 (ANI): A team of scientists, from NOAA (National Oceanic and Atmospheric Administration) in the US, has integrated three-dimensional (3-D) data across coastal seascapes to study climate effects on young fish.

The scientists are viewing real-time underwater images and environmental data to try to figure out what lives in the two areas of ocean off the coasts of northern New Jersey and Long Island, New York, and how climate change is affecting marine life, especially very young fish.

According to John Manderson, a fishery biologist with NOAA’s Northeast Fisheries Science Center (NEFSC), “These areas are much more dynamic than terrestrial landscapes and not what we are used to thinking about the ocean.”

“People look at the ocean floor as the habitat, but don’t think about the connection with the water column above it and how ocean fronts, like atmospheric weather, move through to create a constantly changing environment that affects fish and other marine life,” he explained.

“It is a seascape, a moving 3-D environment,” he added.

Manderson and colleagues in the NEFSC’s Behavioral Ecology Branch recently completed their first two-week cruise to the study area for the 2008 Ecology of Coastal Ocean Seascapes (ECOS) project. Another two-week cruise will be conducted in July, a third in September.

The goal of ECOS is to view the two seascapes in an integrated way using real-time data, focusing on the distribution and condition of early life stages of fishes, and develop models to aid fisheries research and management.

For example, the models could ultimately be used to support fisheries managers to make informed decisions regarding the importance of habitat type for managed fish species, and to help answer questions about effects of climate change on the success of fish stocks.

Working in depths up to 60 meters (about 100 feet), the research team use the various real-time data they receive from above and below the surface to develop a track line or sampling route of the ocean floor within their study areas.

They tow a small video camera sled, stop at stations along the track to sample from the surface to the seafloor with a CTD (conductivity, temperature, density) recorder, and collect other environmental data. A beam trawl is used to collect specimens and to groundtruth the video imagery.

Tissue and diet samples are collected from the animals and brought back to the laboratory.

“We’re using a variety of real and near real-time data that integrate information and present a three-dimensional view of the environment,” said Manderson.

“We’re able to move with a moving ocean, sampling with advanced technology and seeing it as it happens so we can adjust our sampling strategies as necessary. It is exciting to think of the possibilities,” he added. (ANI)

Indian researchers find Japanese encephalitis virus is ‘double trouble’ for the brain

Tue, 08 Jul 2008 10:39:00 -0400

A new study from the National Brain Research Center at Manesar, Haryana, has found that the Japanese encephalitis virus or ‘brain fever’ virus damages the brain in two ways, often causing those recovering to commonly encounter psychiatric problems like mental retardation, learning disabilities, speech and movement disorders and behavioural abnormalities.

Dr. Anirban Basu and his graduate student Sulagna Das have found that the virus behind the disease damages the brain not only by killing brain cells, but also by preventing the birth of new cells from neural stem/progenitor cells (NPC) and depleting the NPC pool.

"It''s a double hit to the brain, the JE virus causes brain injury by killing neurons as well as prevents its repair," said lead researcher Basu said in a statement.

The children are more vulnerable targets of this virus, which causes massive neuronal loss in the Central Nervous System.

"Children are at a dynamic stage of brain development, hence infection at this stage can have devastating effects on mental functions later in life. Our study has tried to explore how JEV infection leads to development of long-term cognitive deficits in the survivors", said Basu who has been working in the neurobiology of JEV infection for the past four years.

A report on the study, published online in the Journal of Neurochemistry, quoted the researcher as saying: "The breakthrough here is that the JE virus prevents neural stem and progenitor cells in the brain from dividing; it hangs them up.”

Basu said: "It''s the first time that a mosquito-borne virus has ever been shown to affect neural stem cells."

He added: “The progressive infection in these cells eventually results in decrease in proliferation ability, providing a possible explanation for their diminished pool upon infection. The neurological and cognitive deficits in the JE survivors could be related to the drop in NPC cells in the neurogenic region of the brain called the subventricular zone".

When the researchers studied mouse models of JE, they observed a significant decrease in the actively proliferating NPCs in the subventricular zone or the primary niche of post-natal neurogenesis.

Over the years, JE has become a major cause of mortality and morbidity in wide areas of SE Asia.

The very high incidence of permanent and disabling neurological sequelae has considerable socioeconomic impact.

"Knowing the mechanism, we can start to approach this therapeutically," Basu said.

"This indicates that we might eventually treat this form of neurological and psychiatric problems by either ramping up brain repair or protecting the repair mechanism," Das added. (ANI)

Coming soon, a laser gun that can detect roadside bombs

Tue, 08 Jul 2008 10:38:00 -0400

Researchers at Oak Ridge National Laboratory in Tennessee have developed a laser system that can safely tell if a suspicious package is an explosive, from up to 100 meters away.

“There are a number of ways to look for explosives. But its a lot nicer if you don''t have to walk up to a bomb to find out what it is,” Discovery News quoted Oak Ridge National Laboratory researcher Larry Senesac, as saying.

According to scientists, the same technology that can help save soldiers from roadside bombs can also eventually spare civilians from food poisoning.

The system is based on a series of quantum cascade, solid state lasers.

Each laser sends out a pulse of light in specific infrared frequencies.

When the lasers hit an object coated with residue from explosives, the light scatters. Some of it bounces back and is picked up by quartz crystals, which act like tuning forks, changing the electromagnetic waves into acoustic waves.

By determining which quartz crystals are activated, and running that specific activation signature through a computer with the chemical signatures of known explosive agents, the system can determine which type of explosive was used.

"This is the first device of its kind," said Charles Van Neste, also of Oak Ridge National Laboratory and the lead author on the paper, which appears in Applied Physics Letters 92.

The new system is so sensitive it can even pick up traces of TNT and other explosives floating in the air. In a different setting, the same system could be programmed pick up signatures associated with spoiled food. (ANI)

Scientists come up with an eco-friendly solution for biofuel production

Tue, 08 Jul 2008 10:37:00 -0400

A group of scientists have come up with an eco-friendly solution for biofuel production in the form of using plants to make the enzymes that can break down the plant material into useable compounds.

With the current drive towards production of alternative fuels from plant material, enzymes, which can break down this material into useable compounds, are required in industrial quantities and at a low cost.

Now, one group of scientists from Texas A&M University in the US has come up with a solution: using plants to make the enzymes.

Traditional methods of generating enzymes for biofuel production currently operate at over five times the target cost required to make the fuels financially competitive.

By using plants that have been engineered to make the proteins, Professor Zivko Nikolov, who leads the Bioseparations Lab at Texas A&M University, believes that the target can be met.

His group, which has expertise in the development of economic processing techniques, have designed processing strategies which allow multiple products to be obtained from each crop, making the whole process more economically viable.

“One of our projects focuses on producing cellulases, enzymes which can break down biomass, in maize seed,” said Nikolov.

“By carefully designing the processing chain, from a single crop of maize we can deliver oil that can be turned into biodiesel, cellulose that can be used to make other biofuels, and fibre and protein which can be used as animal feed, as well, of course as the enzymes themselves,” he added.

According to Nikolov, “These multiple products offset the outlay on the enzyme purification process, meaning we can make enzymes far more cost-effectively than is achievable using traditional fermentation methods.”

In the 1990s, there was much interest in using plants to make both industrial enzymes and pharmaceuticals.

But, in the last five years such industrial enzyme developments have gone out of fashion, largely due to production costs that simply weren’t viable, combined with public unease.

Now, Professor Nikolov’s group has brought this technology back into the picture.

“The economic improvements that we have delivered to the processing pathway, combined with a greater public acceptance of transgenic plants, mean that we can now develop the full potential of this technology,” said Nikolov.

“This in turn will bring us a step closer to the vital challenge of generating cheap alternative fuels over the coming decades,” he added. (ANI)