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Stem cells have GPS to generate proper nerve cells

May 12, 2010 By vani Leave a Comment

Washington, May 12 (ANI): Swedish researchers have discovered an unknown GPS function that regulates how stem cells produce different types of cells in different parts of the nervous system.

The discovery by Stefan Thor, professor of Developmental Biology, and graduate students Daniel Karlsson and Magnus Baumgardt, at Linköping University in Sweden, could improve our understanding of how stem cells work, which is crucial for our ability to use stem cells to treat and repair organs.

Stem cells are responsible for the creation of all cells in an organism during development.

Previous research has shown that stem cells give rise to different types of cells in different parts of the nervous system.

This process is partly regulated by the so-called Hox genes, which are active in various parts of the body and work to give each piece its unique regional identity – a kind of GPS system of the body.

But the researchers don’t know how does a stem cell know that it is in a certain region and how does it read the body”s “GPS” signals.

The scientists also wanted to find out how this information is used to control the creation of specific nerve cells.

Thus, the researchers studied a specific stem cell in the nervous system of the fruit fly.

It is present in all segments of the nervous system, but it is only in the thorax, or chest region, that it produces a certain type of nerve cell.

To investigate why this cell type is not created in the stomach or head region they manipulated the Hox genes” activity in the fly embryo.

It turned out that the Hox genes in the stomach region stop stem cells from splitting before the specific cells are produced.

On the other hand, the specific nerve cells are actually produced in the head region, but the Hox genes turn them into another, unknown, type of cell.

Hox genes can thus exert their influence both on the genes that control stem cell division behaviour and on the genes that control the type of nerve cells that are created.

“We constantly find new regulating mechanisms, and it is probably more difficult than previously thought to routinely use stem cells in treating diseases and repairing organs, especially in the nervous system”, said Thor.

The findings are publishing in the online, open-access journal PLoS Biology. (ANI)

Filed Under: International News Tagged With: cells work, Chest Region, Daniel Karlsson, developmental biology, different types of cells, fruit fly, graduate students, Hox Genes, magnus, nerve cell, nerve cells, organism, Parts Of The Nervous System, previous research, Regional Identity, Stem cell, stem cells, Swedish researchers, Thorax, university in sweden

Green algae serve as effective coating substrate in eco-friendly batteries

September 12, 2009 By admin Leave a Comment

Washington, September 11 (ANI): A group of researchers at the Angstrom Laboratory at Uppsala University in Sweden have discovered that the distinctive cellulose nanostructure of the green Cladophora algae can serve as an effective coating substrate for use in environmentally friendly batteries.

“These algae has a special cellulose structure characterised by a very large surface area,” said Gustav Nystrom, a doctoral student in nanotechnology and the first author of the research article.

“By coating this structure with a thin layer of conducting polymer, we have succeeded in producing a battery that weighs almost nothing and that has set new charge-time and capacity records for polymer-cellulose-based batteries,” he added.

Despite extensive efforts in recent years to develop new cellulose-based coating substrates for battery applications, satisfactory charging performance proved difficult to obtain.

However, nobody had tried using algal cellulose.

Researcher Albert Mihranyan and Professor Maria Stromme at the Nanotechnology and Functional Materials Department of Engineering Sciences at the Angstrom Laboratory had been investigating pharmaceutical applications of the cellulose from Cladophora algae for a number of years.

This type of cellulose has a unique nanostructure, entirely different from that of terrestrial plants, that has been shown to function well as a thickening agent for pharmaceutical preparations and as a binder in foodstuffs.

The possibility of energy-storage applications was raised in view of its large surface area.

“We have long hoped to find some sort of constructive use for the material from algae blooms and have now been shown this to be possible,” said Maria Stromme, Professor in Nanotechnology and leader of the research group.

“The battery research has a genuinely interdisciplinary character and was initiated in collaboration with chemist professor Leif Nyholm. Cellulose pharmaceutics experts, battery chemists and nanotechnologists have all played essential roles in developing the new material,” she added.

The research introduces an entirely new electrode material for energy storage applications, consisting of a nanostructure of algal cellulose coated with a 50 nm layer of polypyrrole.

Batteries based on this material can store up to 600 mA per cm3, with only 6 per cent loss through 100 charging cycles.

“This creates new possibilities for large-scale production of environmentally friendly, cost-effective, lightweight energy storage systems,” said Maria Stromme. (ANI)

Filed Under: Science News Tagged With: Algae Blooms, angstrom laboratory, battery applications, battery research, cellulose structure, cladophora, conducting polymer, energy storage, green algae, interdisciplinary character, large surface area, materials department, nanostructure, pharmaceutical applications, storage applications, stromme, structure characterised, terrestrial plants, thickening agent, university in sweden, uppsala university in sweden

Climate change mitigation strategies ignore carbon cycling processes of inland waters

September 2, 2009 By admin Leave a Comment

Washington, Sept 2 (ANI): In a new report, scientists have determined that climate change mitigation strategies ignore carbon cycling processes of inland waters.

Scientists from the University of Vienna, Uppsala University in Sweden, University of Antwerp, and the US based Stroud Water Research Center, authored the report, which is published in the September issue of Nature Geoscience.

They argue that current international strategies to mitigate manmade carbon emissions and address climate change have overlooked a critical player – inland waters.

Streams, rivers, lakes, reservoirs, and wetlands play an important role in the carbon cycle that is unaccounted for in conventional carbon cycling models.

According to Dr. Tom J. Battin of the department of Freshwater Ecology at the University of Vienna and lead author of the report, “While inland waters represent only 1 percent of the Earth’s surface, their contribution to the carbon cycle is disproportionately large, underestimated, and not recognized within the models on which the Kyoto protocol was based.”

The team of scientists points out that all current global carbon models consider inland waters static conduits that transfer carbon from the continents to the oceans.

In reality, inland waters are dynamic ecosystems with the potential to alter the fates of terrestrial carbon delivered to them including: burial in sediments leading to long-term storage or sequestration; and metabolism in rivers and subsequent outgassing of respired carbon dioxide to the atmosphere.

“Twenty percent of the continental carbon sequestration actually occurs as burial in inland water sediments,” said Dr. Lars Tranvik, Professor of Limnology at Uppsala University in Sweden.

“River outgassing of respired carbon, contributes carbon to the atmosphere in an amount equivalent to 13 percent of annual fossil fuel burning,” said Dr. Anthony K. Aufdenkampe, a scientist at the Stroud Water Research Center.

Because the amount of atmospheric carbon is well known and conservation of matter requires a balanced global carbon budget, this previously unaccounted for source of carbon to the atmosphere implies the existence of an additional continental carbon sink such as higher rates of biomass accrual in forests.

“A larger accumulation of carbon in forest ecosystems that could offset the outgassing from rivers would be more consistent with current independently-derived estimates of carbon sequestration on the continents,” said Dr. Sebastian Luyssaert of the department of Biology at University of Antwerp in Belgium. (ANI)

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Online newspaper archives can help trace changes in language usage

June 27, 2009 By admin Leave a Comment

Washington, June 27 (ANI): Experts at Uppsala University in Sweden have shown that changes in language usage-which may make it possible to attain an entirely new degree of precision in dating-can be tracked by using gigantic newspaper archives.

The researchers used historical collections that included everything ever written in a dozen American and British newspapers since they started-which they could access because the material is available electronically these days-for the purpose of their study.

Together, according to them, the news and feature articles, editorials and commercial and classified advertisements contained in the archives comprise tens of billions of words.

In his dissertation in English linguistics, Donald MacQueen has examined the word million in English, especially how language usage shifted from the previously nearly totally dominant “five millions of inhabitants” to today’s “five million inhabitants”.

He says that the electronic collections of texts, which only recently became available, helped him pin down when and where the modern expression began to take over.

“When you study the occurrence of uncommon words in smaller corpora (text archives) of one or a few million words, you only get a few examples to analyse. These collections are much larger, and they have enabled me to obtain extremely reliable historical data for one year at a time. In this way I have been able to trace the shift with a precision that was not previously possible in linguistic studies,” he says.

He said that the study suggested that the modern construction took over in the American newspapers in the middle of the 1880s, and in the British The Times only in the mid 1910s.

The study also showed that the transitional period was shorter in The Times, he added.

These circumstances, according to MacQueen, indicate that usage in American newspapers influenced and accelerated the shift in the British newspaper.

MacQueen further revealed that the shift took place at the height of the British empire, and roughly when the US economy overtook the British for the first time.

“Another discovery I made, thanks to the huge amount of data, is that when the use of the two constructions began to be roughly equal in frequency, the newspapers chose quite simply to avoid using such constructions, writing numeral expressions instead. After World War II, when there was no longer any doubt which construction was the ‘right’ one, the newspapers reverted to writing number-word expressions again,” he says.

The dissertation also includes a comparison with languages like French and German, where the corresponding grammatical shift regarding the word million from being a noun to an ordinary number word has not yet taken place.

“But in the long perspective we can expect this change to occur in those languages as well. The shift is a universal phenomenon when it comes to number words,” says MacQueen. (ANI)

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Gecko-inspired multifocal contact lenses, cameras on the anvil

May 8, 2009 By admin Leave a Comment

Washington, May 8 (ANI): Scientists are all set to harness the mechanism behind nocturnal geckos’ unique ability to see colours at night, in making multifocal contact lenses and better cameras.

Researchers at Lund University in Sweden have found that the key to the exceptional night vision of the nocturnal helmet gecko is a series of distinct concentric zones of different refractive powers.
The multifocal optical system in geckos is comprised of large cones, which was calculated to be over 350 times more sensitive than human cone vision at the human colour vision threshold.

“We were interested in the geckos because they – and other lizards – differ from most other vertebrates in having only cones in their retina.With the knowledge from the gecko eyes we might be able to develop more effective cameras and maybe even useful multifocal contact lenses,” said project leader Dr. Lina Roth, from the Department of Cell and Organism Biology at the university.

The nocturnal geckos’ multifocal optical system gives them an advantage because light of different ranges of wavelengths can focus simultaneously on the retina.

Another possible advantage of their optical structure is that their eyes allow them to focus on objects at different distances, which makes their multifocal eye to generate a sharp image for at least two different depths.

Roth said that geckos that are active during the day do not possess the distinct concentric zones and are considered monofocal.

The scientists also developed a new method to gather optical data from live animals without any harm to their modifications to the Hartmann-Shack wavefront sensor.

“Studies of animals with relatively large eyes, such as owls and cats, have included surgery and fixation of the head. In this study, we demonstrate that it is possible to obtain high-resolution wavefront measurements of small, unharmed gecko eyes without completely controlling the gaze or the accommodation of the animal eyes,” said the authors.

The study has been published online in the Journal of Vision. (ANI)

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Vehicular pollutants stick to the lung more than other smoke, dust particles

April 2, 2009 By admin Leave a Comment

London, April 2 (ANI): In what may lead to a change in the way air pollution is evaluated, scientists at Lund University in Sweden have shown that the tiny particles from traffic fumes are far “stickier” than other smoke and dust particles.

Research leader Jakob Londahl came to this conclusion after measuring how many airborne particles stay behind in the lungs.

For that purpose, the researchers used a new device called RESPI, which brings air being inhaled in through one chamber, and exhaled air out through a second chamber.

The device helped the researchers analyse particle number and size in both chambers.

Londahl asked nine healthy adults to breathe into the RESPI device while standing on the kerbside of a six-lane Copenhagen boulevard, which sees around 65,000 vehicles pass by on a typical weekday.

“We found most traffic fume particles to be very small and hydrophobic (having little affinity for water), meaning they did not grow bigger once inside the wet lung. But small particles get deposited in the lung more easily,” New Scientist magazine quoted the researcher as saying.

Having noted the street measurements, the researchers compared them with the deposition of particles inhaled from an open fire and a biomass burner, which was measured in a previous study.

The team observed that for each microgram of particles inhaled, 16 times as many of the tiny traffic particles got retained in the lung than either the larger soot particles from wood smoke or the moisture-sensitive salts from the biomass burner that clump into bigger particles once inside the lung.

According to them, the traffic deposits also had three times the surface area of those inhaled in the biomass combustion study.

“There is some debate as to what characteristics of particles make them unhealthy – if it is mass or surface area or number. Our results support that it is the latter two, but at the moment, most air quality policies limit amounts by mass,” says Londahl.

The researchers next plan to study how the deposition of traffic exhaust particles differs between healthy people and those with respiratory diseases.

A research article on this study has been published in the journal Environmental Science and Technology. (ANI)

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Permafrost likely to shrink in northern Sweden

February 22, 2009 By admin Leave a Comment

Washington, Feb 21 (ANI): A new study by researchers from Lund University in Sweden has determined that permafrost is thawing in northern Sweden, because of warmer summers and more winter precipitation.

According to a report in ENN (Environmental News Network), the study was undertaken by physical geographer Margareta Johansson at Lund University, who studied lowland permafrost in peat mires surrounding Abisko.

Permafrost is ground that is frozen year round at least two years in a row. North of the Arctic Circle permafrost is common due to the cold climate.

Johansson said that permafrost is being affected by climate changes.

“At one of our sites, permafrost has completely disappeared from the greater part of the mire during the last decade,” she said.

In areas where permafrost is thawing, the ground becomes unstable and can collapse. This can be a local and regional problem in areas with cities and infrastructure.

Moreover, the thaw can cause increased emissions of the greenhouse gases carbon dioxide and methane from the ground.

Roughly 25 percent of all land surface in the northern hemisphere are underlain by permafrost.

The thawing of permafrost that occurs today is likely to continue, in Johansson’s view.

She regards it as probable that there will be no permafrost in lowland areas around Abisko in 50 years.

“With the present climate it is likely that the changes seen in permafrost in the Abisko area will also occur in other areas, and my study can therefore provide a basis for studies in other geographic areas that are next in line,” she said.

Johansson’s research shows that the permafrost in the Abisko area is thawing both from above and from below.

From above, it is thawing primarily because the summers have become warmer and because the snow cover has become thicker in winter.

A thicker snow layer acts as an insulating blanket, which means that the ground does not get as cold as it would under a thinner layer of snow.

From below, the permafrost is thawing probably as a result of greater mobility in the groundwater.

According to Johansson, the annual precipitation of both rain and snow has increased dramatically during the last decade.

More rain and more melted snow create more movement down in the groundwater, which thaws the permafrost. (ANI)

Filed Under: Science News Tagged With: arctic circle, carbon dioxide and methane, climate changes, cold climate, environmental news, geographic areas, greenhouse gases, land surface, last decade, lowland areas, lund university in sweden, mires, northern hemisphere, northern sweden, permafrost, regional problem, snow cover, snow layer, university in sweden, winter precipitation

Process separate from natural selection also drives human evolution

January 27, 2009 By admin Leave a Comment

Washington, Jan 27 (ANI): A new research, led by a group at Uppsala University in Sweden, has suggested that apart from natural selection, a separate neutral (nonadaptive) process has also made a significant contribution to human evolution.

The researchers identified fast evolving human genes by comparing our genome with those of other primates.

However, surprisingly, the patterns of molecular evolution in many of the genes they found did not contain signals of natural selection.

Instead, their evidence suggests that a separate process known as BGC (biased gene conversion) has speeded up the rate of evolution in certain genes.

This process increases the rate at which certain mutations spread through a population, regardless of whether they are beneficial or harmful.

“The research not only increases our understanding of human evolution, but also suggests that many techniques used by evolutionary biologists to detect selection may be flawed,” said scientist Matthew Webster.

BGC is thought to be strongest in regions of high recombination, and can cause harmful mutations can spread through populations.

The results lead to the provocative hypothesis that, rather than being the result of Darwinian selection for new adaptations, many of the genetic changes leading to human-specific characters may be the result of the fixation of harmful mutations.

This contrasts the traditional Darwinistic view that they are the result of natural selection in favour of adaptive mutations. (ANI)

Filed Under: Science News Tagged With: adaptations, adaptive mutations, bgc, darwinian selection, evolutionary biologists, fixation, gene conversion, Genetic changes, genome, harmful mutations, human evolution, human genes, matthew webster, molecular evolution, natural selection, nonadaptive, primates, recombination, university in sweden, uppsala university in sweden

Oldest shark braincase shakes up assumptions about vertebrate evolution

January 15, 2009 By Rajesh Leave a Comment

Washington, Jan 15 (ANI): A team of scientists has said that the earliest known braincase of a shark-like fish has shown that some assumptions about the early evolution of vertebrates are “completely wrong.”

According to a report in National Geographic News, the specimen is of a 415-million-year-old Ptomacanthus, which is only the second known example of a braincase from an Acanthodian, a long-extinct group of fossil fish.

The other braincase, from a species called Acanthodes, dates to a hundred million years after the Acanthodian group came into existence, casting most of this period of the group’s evolution into shadow.

“We’ve known about (Acanthodians) for 150 years or more, but the braincase has always been missing,” said study lead author Martin Brazeau, a Ph.D. student at Uppsala University in Sweden. “To fit it in now is kind of exceptional,” he added.

Before this discovery, most scientists believed that the braincases of Acanthodians resembled those of bony fish, and were thus related to this type of animal.

But, data from the new fossil support an emerging idea that the ancient group of fish included a diverse tableau of shapes and characteristics that defy clear-cut categories.

The primitive fish’s softer skeletons did not fossilize well, leaving scientists few braincases or other parts to study.

But, Brazeau suspected that in the right circumstances, some bones could withstand time.

So, he took a closer look at the well-preserved Ptomacanthus specimen that had been in the literature for 30 years.

“Sure enough, the specimen had its braincase preserved,” he said.

The ancient creature has distinct features of a shark-swirling rows of teeth and a short snout, for instance-and looked little like the early bony fish suggested by the Acanthodes braincase.

Such differences within the same group rock earlier assumptions that a certain set of species with similar characteristics fit in clearly defined categories.

Grouping fish in this way “gives us a coarse picture of evolution,” said Brazeau.

“We need to find intermediaries between groups, find more fossils, and go and see if we’ve missed some,” he added.

According to Michael Coates, a professor of organismal biology at the University of Chicago, “The common perception is that sharks are somehow primitive relative to bony fish – foundations that are sketchy at best.

“It’s an important piece in the puzzle for trying to understand one of the biggest events not only in our own evolutionary history, but also the vast majority of living animals with backbones,” he said. (ANI)

Filed Under: Educational News, Science News Tagged With: acanthodian, acanthodians, ancient creature, ancient group, author martin, bony fish, braincase, brazeau, distinct features, evolution of vertebrates, extinct group, fossil fish, group of fish, grouping fish, hundred million, National Geographic News, primitive fish, snout, university in sweden, uppsala university in sweden

Potential new weapon against HIV identified

January 14, 2009 By Rajesh Leave a Comment

Washington, Jan 13 (ANI): An international team of researchers has identified a potentially new weapon in battle against HIV infection – blood types.

Researchers from Canadian Blood Services, The Hospital for Sick Children (SickKids) and Lund University in Sweden have discovered that certain blood types are more predisposed to contracting HIV, while others are more effective at fending it off.

A carbohydrate-containing antigen, termed Pk blood group which is distinct from the well-known ABO and Rh blood grouping systems, is present at variable levels on the surface of white and red blood cells in the general population.

Their study shows that cells from rare individuals ( 1 in a million) who produce excess of this blood group antigen have dramatically reduced sensitivity to HIV infection.

Conversely, another slightly more common subgroup of people who do not produce any Pk ( 5 in a million) was found to be much more susceptible to the virus.

“This study is not suggesting that your blood type alone determines if you will get HIV. However, it does suggest that individuals who are exposed to the virus, may be helped or hindered by their blood status in fighting the infection,” said lead author Dr. Don Branch of Canadian Blood Services.

Increasing the level of the Pk antigen in cells in the laboratory also resulted in heightened resistance to HIV, while lowering it increased susceptibility.

“This discovery implicates the Pk level as a new risk factor for HIV infection and demonstrates the importance of blood-group-related science,” said Dr. Olsson.

The study is published in Blood, which is currently available online. (ANI)

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