Knowledge Update

New York, Sep 22 (IANS) Smoking, a leading preventable cause of deaths worldwide, impacts the human DNA for more than 30 years even after one quits, a study has found.

The findings showed that smoking leaves its "footprint" on the human genome in the form of DNA methylation -- a process by which cells control gene activity.

Methylation, one of the mechanisms of the regulation of gene expression, affects what genes are turned on, which has implications for the development of smoking-related diseases.

"Our study has found compelling evidence that smoking has a long-lasting impact on our molecular machinery, an impact that can last more than 30 years," said lead author Roby Joehanes, instructor at Harvard Medical School in Massachusetts, US.

For people who stopped smoking, the majority of DNA methylation sites returned to the levels that are seen in those who never smoked within five years of quitting it.

However, some DNA methylation sites persisted even after 30 years of quitting.

Even decades after stopping, former smokers are at long-term risk of developing diseases including cancers, chronic obstructive pulmonary disease, and stroke. 

The most statistically significant methylation sites were linked to genes enriched for association with numerous diseases caused by cigarette smoking, such as cardiovascular diseases and certain cancers.

DNA methylation could be an important sign that reveals an individual's smoking history, and could provide researchers with potential targets for new therapies, the researchers said.

For the study, the team conducted a meta-analysis of DNA methylation sites across the human genome using blood samples taken from nearly 16,000 participants.

The researchers compared DNA methylation sites in current and former smokers to those who never smoked.

Smoking-associated DNA methylation sites were associated with more than 7,000 genes, or one-third of known human genes.

The researchers suggest that some of these long-lasting methylation sites may be marking genes potentially important for former smokers who are still at increased risk of developing certain diseases. 

The discovery of smoking-related DNA methylation sites raises the possibility of developing biomarkers to evaluate a patient's smoking history, as well as potentially developing new treatments targeted at these methylation sites.

The results were published in the journal Circulation: Cardiovascular Genetics.

Washington, Sep 22 (IANS) The microbes that people have brought with them so far to the International Space Station -- and left behind -- are the focus of a new collaborative research opportunity from NASA and the non-profit Alfred P. Sloan Foundation.

Microbiome research on the space station is an important area of research for NASA as it prepares astronauts for future long duration spaceflight. 

"NASA is incredibly excited to partner with the Sloan Foundation through a Space Act Agreement to look at the microbiome of the space station to better understand how to control the microbial environment in future human exploration spacecraft," David Tomko, space biology programme scientist at NASA, said in a statement on Thursday.

More than 200 people have crossed the airlock threshold to the International Space Station to conduct research that benefits people on Earth and NASA's ambitious plan to send humans to Mars.

Humans bring microbes everywhere they go ? some of which reside inside the body, such as the intestinal tract. Others are outside the body on skin and clothes, for example. 

When these collective microbial communities enter a human-made environment like the International Space Station they create their own microbial ecosystem known as the Microbiome of Built Environments (MoBE).

NASA is seeking proposals from postdoctoral fellows to analyse the microbial communities inside the space station to determine how the communities colonise, adapt and evolve. 

The researchers will have access to a collection of space station microbial samples gathered over a decade or more, and archived at NASA's Johnson Space Center in Houston.

​New York, Sep 22 (IANS) Children and teenagers who are obese have different microorganisms living in their digestive tract than those who are lean, according to a new study.

The study finds gut microbiota or gut flora is closely related to fat distribution in children and teenagers.

"Our findings show children and teenagers with obesity have a different composition of gut flora than lean youth," said Nicola Santoro, Researcher at the Yale University in Connecticut, US. 

"This suggests that targeted modifications to the specific species composing the human microbiota could be developed and could help to prevent or treat early-onset obesity in the future," said Santoro. 

The study examined gut microbiota and weight in 84 children and teenagers, who were between seven and 20 years old. The participants included 27 obese, 35 severely obese, seven overweight and 15 with normal weight.

The researchers analysed the participants' gut microbiota and performed an MRI to measure body fat partitioning. They also tested blood samples and reviewed their three-day food diary.

They found eight groups of gut microbiota that were linked to the amount of fat in the body. Four of the microbial communities were seen flourishing in children and teens with obesity as compared to their normal-weight counterparts.

Smaller amounts of the other four microbial groups were found in participants, who were obese compared to children and teenagers of normal weight. 

The gut microbiota found in youth, who were obese, tended to be more efficient at digesting carbohydrates than those found in teenagers and children's gut from normal weight category.

In addition, the children with obesity had higher levels of short chain fatty acids in the blood than those of normal weight. 

The study found short chain fatty acids -- produced by some gut bacteria -- to be associated with the production of fat in the liver.

"Our research suggests that short chain fatty acids can be converted to fat within the liver and then accumulate in the fat tissue," said Santoro.

The researchers said this association could signal that children with certain gut bacteria face a long-term risk of developing obesity. 

The study was published in the journal Clinical Endocrinology and Metabolism.

Washington, Sep 23 (IANS) Astronomers using NASA's Hubble Space Telescope, and a trick of nature, have confirmed the existence of a planet orbiting two stars in the system OGLE-2007-BLG-349, located 8,000 light-years away towards the centre of our galaxy.

The planet orbits roughly 483 million kilometres from the stellar duo, about the distance from the asteroid belt to our sun, NASA said in a statement on Thursday.

It completes an orbit around both stars roughly every seven years. The two red dwarf stars are a mere 11 million miles apart, or 14 times the diametre of the moon's orbit around Earth.

The Hubble observations represent the first time such a three-body system has been confirmed using the gravitational microlensing technique.

Gravitational microlensing occurs when the gravity of a foreground star bends and amplifies the light of a background star that momentarily aligns with it. The particular character of the light magnification can reveal clues to the nature of the foreground star and any associated planets.

The objects were discovered in 2007 by an international collaboration of five different groups. These ground-based observations uncovered a star and a planet, but a detailed analysis also revealed a third body that astronomers could not definitively identify.

"The ground-based observations suggested two possible scenarios for the three-body system: a Saturn-mass planet orbiting a close binary star pair or a Saturn-mass and an Earth-mass planet orbiting a single star," explained the paper's first author David Bennett of the NASA Goddard Space Flight Center in Greenbelt, Maryland. 

The sharpness of the Hubble images allowed the research team to separate the background source star and the lensing star from their neighbours in the very crowded star field. 

The Hubble observations revealed that the starlight from the foreground lens system was too faint to be a single star, but it had the brightness expected for two closely orbiting red dwarf stars, which are fainter and less massive than our sun. 

"So, the model with two stars and one planet is the only one consistent with the Hubble data," Bennett said.

NASA's Kepler probe has discovered 10 other planets orbiting tight binary stars, but these are all much closer to their stars than the one studied by Hubble.

The team's results have been accepted for publication in The Astronomical Journal.

​London, Sep 23 (IANS) Dysregulation of the DNA -- an important cause of ageing -- does not take place in some people, while in some individuals, the DNA appears to be youthful despite their advanced years.

This dysregulation of the DNA can act as a precursor to various diseases, including cancer, and on the other hand, youthful DNA may prevent the disease, the researchers have found.

The DNA of young people is regulated to express the right genes at the right time. With the passing of years, the regulation of the DNA gradually gets disrupted, which is an important cause of ageing, the study said. 

"The study suggests that the dysregulation of the DNA is a fundamental process that could push the risk of different diseases in the wrong direction," said Bas Heijmans, an epigeneticist at the Leiden University Medical Center in the Netherlands. 

Further, in cancer cells changes in the regulation of the DNA at the same sites was found as if the differences occurring with ageing were a precursor of the disease, the study said. 

"We therefore want to study whether a dysregulated DNA increases the risk of different forms of cancer and, conversely, a 'youthful' DNA is protective," added Roderick Slieker from Leiden University Medical Center.

For the study, the researchers charted the regulation of the DNA of over 3,000 people by measuring the level of methylation -- a process by which cells control gene activity -- at close to half a million sites across the human DNA. 

Not everyone in the study showed equal evidence of an age-related dysregulation of the DNA. They were looking for sites where the difference in regulation increased between people as life progressed. 

Some elderly people had DNA that was regulated as if they were still 25 years old. In these individuals, genes characteristic of the ageing process were much less active, the researchers said.

"We believe we may have caught the ageing process in the act. The dysregulation of the DNA that we discovered went hand in hand with higher activity in genes that continuously try to repair damage to cells. This process is not fully effective and in the long run leads to ageing," Heijmans explained, in the research published in the journal Genome Biology.

London, Sep 23 (IANS) Using data from the European Space Agency's Planck satellite, researchers have confirmed what cosmologists have assumed all along - our universe expands the same way in all directions.

Most current cosmological studies assume that the universe behaves identically in every direction. If this assumption were to fail, a large number of analyses of the cosmos and its content would be flawed.

"We're very glad that our work vindicates what most cosmologists assume. For now, cosmology is safe," said study first author Daniela Saadeh from University College London.

The new study, published today in the journal Physical Review Letters, studied the cosmic microwave background (CMB) which is the remnant radiation from the Big Bang. 

"The finding is the best evidence yet that the universe is the same in all directions," she said.

"Our current understanding of the universe is built on the assumption that it doesn't prefer one direction over another, but there are actually a huge number of ways that Einstein's theory of relativity would allow for space to be imbalanced. Universes that spin and stretch are entirely possible, so it's important that we've shown ours is fair to all its directions," she explained.

The team used measurements of the CMB taken between 2009 and 2013 by the European Space Agency's Planck satellite. 

The spacecraft recently released information about the polarisation of CMB across the whole sky for the first time, providing a complementary view of the early universe that the team was able to exploit.

The researchers modelled a comprehensive variety of spinning and stretching scenarios and how these might manifest in the CMB, including its polarisation. They then compared their findings with the real map of the cosmos from Planck, searching for specific signs in the data.

"We calculated the different patterns that would be seen in the cosmic microwave background if space has different properties in different directions. Signs might include hot and cold spots from stretching along a particular axis, or even spiral distortions," Saadeh noted.

"We then compare these predictions to reality. This is a serious challenge, as we found an enormous number of ways the Universe can be anisotropic," collaborating author Stephen Feeney from Imperial College London added.

The researchers calculated the odds that "the universe prefers one direction over another at just one in 121,000".

New York, Sep 23 (IANS) Individuals carrying a gene mutation are at an increased risk of developing neurological disorder related to touch and proprioception -- our "sixth sense" or body awareness -- a study has found.

The study was conducted on two young patients -- one nine and the other 19-years-old -- who were diagnosed with progressive scoliosis -- a unique neurological disorder in which a person's spine has a sideways curve.

The findings revealed that a gene called PIEZO2 that controls specific aspects of human touch and proprioception, is either directly required for the normal growth and alignment of the skeletal system or that touch and proprioception indirectly guide skeletal development. 

"The results establish that PIEZO2 is a touch and proprioception gene in humans. Understanding its role in these senses may provide clues to a variety of neurological disorders," said Carsten G. Bonnemann from the National Institute of Neurological Disorders and Stroke (NINDS) -- a US based public research organisation.

The mutations in the PIEZO2 gene caused the two patients to have movement and balance problems as well as the loss of some forms of touch, the study said.

"Our results suggest they are touch-blind. The patient's version of Piezo2 protein may not work, so their neurons cannot detect touch or limb movements," added Alexander T. Chesler from National Center for Complementary and Integrative Health (NCCIH) -- a US based public scientific research agency. 

Further examinations suggested that the patients also lacked body awareness. They could not feel vibrations from a buzzing tuning fork. Nor could they tell the difference between one or two small ends of a caliper pressed firmly against their palms. 

Nevertheless, the patients could feel other forms of touch. They could feel the stroking or brushing of hairy skin. 

However, one claimed it felt prickly instead of the pleasant sensation reported by unaffected volunteers. 

Despite these differences, the patients' nervous systems appeared to be developing normally, the researchers said. 

They were able to feel pain, itch, and temperature normally. The nerves in their limbs conducted electricity rapidly and their brains and cognitive abilities were similar to the control subjects of their age.

"What's remarkable about these patients is their nervous systems compensate for their lack of touch and body awareness," Bonnemann said. 

The study suggests the nervous system may have several alternate pathways that we can tap into when designing new therapies.

Previous studies have showed that mutations in PIEZO2 may have various effects on the Piezo2 protein that may result in genetic musculoskeletal disorders, including distal arthrogryposis type 5, Gordon Syndrome, and Marden-Walker Syndrome, the researchers concluded in the paper, published in the New England Journal of Medicine.

​Washington, Sep 22 (IANS) The inclusion of the Chinese yuan in the Special Drawing Right (SDR) basket by the International Monetary Fund (IMF) is an important milestone for the international monetary system, said a senior IMF official.

​New York, Sep 22 (IANS) Greenland lost nearly 2,700 gigatons of ice from 2003-2013, not about 2,500 gigatons as scientists previously thought -- a 7.6 percent difference, a study says.

"It's a fairly modest correction," said study co-author Michael Bevis of The Ohio State University in the US. 

"It doesn't change our estimates of the total mass loss all over Greenland by that much, but it brings a more significant change to our understanding of where within the ice sheet that loss has happened, and where it is happening now," Bevis, who is also the leader of GNET, the Greenland GPS Network, said.

The researchers found that the same hotspot in the Earth's mantle that feeds Iceland's active volcanoes has been playing a trick on the scientists who are trying to measure how much ice is melting on nearby Greenland.

According to the new study published in the journal Science Advances, the hotspot softened the mantle rock beneath Greenland in a way that ultimately distorted their calculations for ice loss in the Greenland ice sheet. This caused them to underestimate the melting by about 20 gigatons (20 billion metric tons) per year.

The new results revealed that the pattern of modern ice loss is similar to that which has prevailed since the end of the last Ice Age.

During the last Ice Age, Greenland's ice sheet was much larger than now, and its enormous weight caused Greenland's crust to slowly sink into the softened mantle rock below. 

When large parts of the ice sheet melted at the end of the Ice Age, the weight of the ice sheet decreased, and the crust began to rebound. It is still rising, as mantle rock continues to flow inwards and upwards beneath Greenland.

"This result is a detail, but it is an important detail," Bevis said. 

"By refining the spatial pattern of mass loss in the world's second largest -- and most unstable -- ice sheet, and learning how that pattern has evolved, we are steadily increasing our understanding of ice loss processes, which will lead to better informed projections of sea level rise," Bevis noted.

The team used GPS to measure uplift in the crust all along Greenland's coast. 

That is when they discovered that two neighbouring stations on the east coast were uplifting far more rapidly than standard models had predicted.

"We did not expect to see the anomalous uplift rates at the two stations that sit on the 'track' of the Iceland hot spot," Bevis said. 

"We were shocked when we first saw them. Only afterwards did we make the connection," Bevis pointed out.

He added that the discovery holds big implications for measuring ice loss elsewhere in the world.

​New York, Sep 22 (IANS) Nearly four per cent of all deaths - approximately 433,000 per year -- are due to the fact that people worldwide spend more than three hours a day just sitting down, a study has found.

Various studies over the last decade have demonstrated how the excessive amount of time we spend sitting down may increase the risk of death, regardless of whether or not we exercise.

The new study, published in the American Journal of Preventive Medicine, now estimates the proportion of deaths attributable to that 'chair effect' in the population of 54 countries, using data from 2002 to 2011.

"It is important to minimise sedentary behaviour in order to prevent premature deaths around the world," said lead author of the study Leandro Rezende from University of Sao Paulo in Brazil.

He also highlighted that "cutting down on the amount of time we sit could increase life expectancy by 0.20 years in the countries analysed."

The results revealed that over 60 per cent of people worldwide spend more than three hours a day sitting down - the average in adults is 4.7 hours/day -- and this is the culprit behind 3.8 per cent of deaths.

Among the territories studied, there were more deaths in the regions of the Western Pacific, followed by European countries, the Eastern Mediterranean, America and Southeast Asia. 

The highest rates were found in Lebanon (11.6 per cent), the Netherlands (7.6 per cent) and Denmark (6.9 per cent), while the lowest rates were in Mexico (0.6 per cent), Myanmar (1.3 per cent) and Bhutan (1.6 per cent). 

The authors calculated that reducing the amount of time we sit by about two hours (by half) would mean a 2.3 per cent decrease in mortality.

Even a more modest reduction in sitting time, by 10 per cent or half an hour per day, could have an immediate impact on all causes of mortality (0.6 per cebt) in the countries evaluated.

In the words of the experts, measures aimed at addressing the determining factors behind this sedentary conduct would be necessary. 

"Some examples of this approach were recently highlighted by the World Health Organisation," Rezende said.

"For example, a strategic health communication campaign was developed to promote physical activity among women in Tonga (Oceania), while a bicycle-sharing system was developed in Iran in addition to a sustainable transport system in Germany," he noted.