Knowledge Update

​Sydney, Nov 26 (IANS) The number of nitrogen microbes found in an individual's gut play an important role in determining the type of diet strategy that can yield results, a new research has found.

Though there are different ways by which a person can have a good diet, but the same diet does not work in a same way for every individual, according to the study.

"There are many different diet strategies that claim to promote gut health, and until now it has been very difficult to establish clear causality between various types of diet and their effect on the host's microbiome," said lead author Andrew Holmes, Associate Professor from the University of Sydney in Australia.

"This is because there are many complex factors at play, including food composition, eating pattern and genetic background," added Holmes.

For the study, researchers put 858 mice on 25 different diets composed of different amounts of protein, carbohydrates and fat. The results showed that there was a "tipping point" across all diets that related to how nutrients from the diet became available to nitrogen in the gut.

Despite the huge diversity of gut bacteria, two main response patterns emerged. Microbe species either increased or decreased in their abundance depending on the animal's protein and carbohydrate intake.

"The largest nutrient requirements for our gut bacteria are carbon and nitrogen in the foods we eat. As carbohydrates contain no nitrogen but protein does, the bacterial community response to the host animal's diet is strongly affected by this diets' protein-carbohydrate ratio," Holmes said.

The findings showed that the availability of intestinal nitrogen to microbes in the gut plays a key role in regulating interactions between gut microbes and their host animal. 

The same pattern was seen across almost all groups of gut bacteria which indicated that the makeup of the microbial ecosystem is fundamentally shaped by a need to access nitrogen in the intestinal environment, according to the study.

The study aims to promote better dietary combinations to achieve maximum gut health and was published in the journal Cell Metabolism.

Beijing, Nov 26 (IANS) Nearly 12,000 elderly people will receive free bracelets in Beijing that could help prevent them from getting lost, local authorities said on Saturday.

"The bracelets will be given to elderly people who have cognitive problems such as dementia," Xinhua news agency quoted Deputy Mayor of Beijing Wang Ning as saying.

The bracelets are equipped with a GPS. By installing an app on their smart phones, children of the seniors can locate their parents. The elderly can also make emergency calls with the bracelets.

According to Wang, they are also installing emergency call devices and smoke detectors for elderly people living alone. 

In 2015, about 222 million of the country's 1.3 billion citizens were aged 60 or older.

According to a survey, 1,370 senior citizens -- with an average age of 76 -- go missing every day.

By the end of November, the equipment will be given to at least 5,800 households.

London, Nov 26 (IANS) Researchers have engineered cells with a "built-in genetic circuit" that produces a molecule that impairs the ability of cancer cells to survive and grow in their low oxygen environment.

The genetic circuit produces the machinery necessary for the production of a compound that inhibits a protein which has a significant and critical role in the growth and survival of tumours. 

This results in the cancer cells being unable to survive in the low oxygen, low nutrient tumour micro-environment.

"In a wider sense, we have given these engineered cells the ability to fight back -- to stop a key protein from functioning in cancer cells," said lead researcher Ali Tavassoli, Professor at the University of Southampton in Britain.

"This opens up the possibility for the production and use of sentinel circuits, which produce other bioactive compounds in response to environmental or cellular changes, to target a range of diseases including cancer," Tavassoli said.

As tumours develop and grow, they rapidly outstrip the supply of oxygen delivered by existing blood vessels. This results in cancer cells needing to adapt to a low oxygen environment.

To enable them to survive, adapt and grow in the low oxygen or 'hypoxic' environment, tumours contain increased levels of a protein called Hypoxia-inducible factor 1 (HIF-1). 

This protein senses reduced oxygen levels and triggers many changes in cellular function, including a changed metabolism and sending signals for the formation of new blood vessels. 

It is thought that tumours primarily hijack the function of this protein (HIF-1) to survive and grow.

"In an effort to better understand the role of HIF-1 in cancer, and to demonstrate the potential for inhibiting this protein in cancer therapy, we engineered a human cell line with an additional genetic circuit that produces the HIF-1 inhibiting molecule when placed in a hypoxic environment," Tavassoli explained. 

"We've been able to show that the engineered cells produce the HIF-1 inhibitor, and this molecule goes on to inhibit HIF-1 function in cells, limiting the ability of these cells to survive and grow in a nutrient-limited environment as expected," Tavassoli noted.

The genetic circuit was incorporated onto the chromosome of a human cell line, which encodes the protein machinery required for the production of their cyclic peptide HIF-1 inhibitor.

The research, published in the journal ACS Synthetic Biology, demonstrates the possibility of adding new machinery to human cells to enable them to make therapeutic agents in response to disease signals.

Washington, Nov 26 (IANS) US online sales surged on Black Friday, with Amazon.com Inc offering the steepest discounts among e-commerce sites as it set the agenda for what has traditionally been the biggest shopping day of the year for brick-and-mortar retailers. Though in-store customer traffic picked up in the afternoon, it paled in comparison to the jump in online sales, NBC news cited analysts as saying. Macy's Inc's website crashed as it saw heavy traffic on Friday. It had to delay customers from entering the site at three different times. Online sales on Friday hit $1.70 billion as of 3 p.m., according to Adobe Digital Index, after reaching $1.13 billion on Thursday, up almost 14 per cent from a year ago. The National Retail Federation expects total sales this holiday season to increase by 3.6 per cent to $655.8 billion, mainly due to the rise in online shopping. This weekend's shopping could reflect signs of faster economic growth in the fourth quarter this year. Administrative assistant Kelsey Gilford, 52, was shopping at Chicago's Water Tower mall on Friday but had already made purchases online on Thursday. "I looked at some online deals on J.C. Penney which were good. I bought a small kitchen appliance yesterday (Thursday)," she said. Amazon.com Inc offered a 42 per cent off, compared with 33 per cent off at Walmart, 35 per cent at Target and 36 per cent at Best Buy. Amazon said Black Friday would surpass last year in terms of the number of items ordered on its website. The Seattle-based company declined to provide specifics. Online shopping continued to grow, with Adobe saying that Black Friday was on track to set a new record by surpassing the $3 billion mark for the first time. It is also expected to become the first day in US retail history to drive over a billion dollars from mobile sales. Mobile accounted for 40 per cent of sales, with 29 per cent from smartphones, and 11 per cent for tablets. Combined with Thursday's $1.93 in online sales on Thanksgiving, the two days are expected to close out at nearly $5 billion in sales. Tamara Gaffney, principal analyst and director, Adobe Digital Insights, said: "We expect Cyber Monday to surpass Black Friday and become the largest online sales day in history with $3.36 Billion." Meanwhile, UK shoppers also rushed to buy Black Friday bargains, as retailers and payment firms reported strong sales. Barclaycard said it had seen a record number of transactions on Friday, while Argos, John Lewis and Currys PC World reported a surge in orders, BBC reported. In the UK, analysts expect sales on Friday to have topped last year's 1.9 billion pound, with people hunting for discounts ahead of an expected rise in prices next year. "The Black Friday promotions at the end of November are the start of a longer, more drawn-out peak season, which begins with most of the activity online and then moves in-store as we get closer and closer to Christmas day," said Richard Jenkings, data analyst at credit reference agency Experian.

Toronto, Nov 26 (IANS) Canadian researchers have developed a novel website that may offer evidence-based ratings on footwear that can reduce the risk of slips and falls on ice in winter.

New York, Nov 26 (IANS) US stocks rallied on Friday, with all three major indices refreshing closing records, as investors continued to digest the Federal Reserve's minutes from its November meeting.

Washington, Nov 25 (IANS) Researchers have found a novel way to make fuel cells more energy efficient and increase their power output by fine-tuning metal catalysts at the atomic scale.

A nano size squeeze can significantly boost the performance of platinum catalysts that help generate energy in fuel cells, according to the new study by scientists at Stanford University.

"Our tuning technique could make fuel cells more energy efficient and increase their power output," said study co-author Yi Cui, Professor at Stanford and SLAC National Accelerator Laboratory in California. 

"It could also improve the hydrogen-generation efficiency of water splitters and enhance the production of other fuels and chemicals," Cui noted.

The team bonded a platinum catalyst to a thin material that expands and contracts as electrons move in and out, and found that squeezing the platinum a fraction of a nanometre nearly doubled its catalytic activity. 

"In this study, we present a new way to fine-tune metal catalysts at the atomic scale," said lead author Haotian Wang, a former graduate student at Stanford now at Harvard University.

"We found that ordinary battery materials can be used to control the activity of platinum and possibly for many other metal catalysts," Wang noted.

The new technique described in the journal Science can be applied to a wide range of clean technologies, including fuel cells that use platinum catalysts to generate energy, and platinum electrolysers that split water into oxygen and hydrogen fuel, Wang said.

Catalysts are used to make chemical reactions go faster while consuming less energy. The performance of a metal catalyst depends on its electronic structure -- that is, how the electrons orbiting individual atoms are arranged.

The team introduced a novel way to compress or separate the atoms by 5 percent, a mere 0.01 nanometer.

"That might not seem like much, but it's really a lot," Cui said.

"We found that compression makes platinum much more active," Wang added. 

"We observed a 90 per cent enhancement in the ability of platinum to reduce oxygen in water. This could improve the efficiency of hydrogen fuel cells," Wang said.

New York, Nov 25 (IANS) Various brain regions that once synchronised their activity during memory tasks become smaller and lose cohesion as people age, says a study.

In the study, researchers from Princeton University in New Jersey, US, described a novel method to characterise and compare the brain dynamics of individual people.

The research showed that regardless of whether we were using memory, directing attention, or resting, the number of synchronous groups of connections within our brain was consistent. 

However, between different individuals, these numbers vary dramatically.

In fact, during memory specific actions, variations between people are closely linked to age.

Younger participants have only a few large synchronous groups that link nearly the entire brain in coordinated activity, while older participants show progressively more but smaller groups of connections.

In the older group this indicates loss of cohesive brain activity -- even in the absence of memory impairment, the authors noted.

"This method elegantly captures important differences between individual brains, which are often complex and difficult to describe," said Elizabeth Davison from Princeton University. 

"The resulting tools show promise for understanding how different brain characteristics are related to behaviour, health, and disease," Davison added.

For the study, the researchers used functional magnetic resonance imaging (fMRI) to record healthy people's brain activity during memory tasks, attention tasks, and at rest. 

For each person, the fMRI data was recast as a network composed of brain regions and the connections between them. 

The scientists then use this network to measure how closely different groups of connections changed together over time.

The study was published in the journal PLOS Computational Biology.

London, Nov 25 (IANS) Researchers have found that depression in young people is often followed by arthritis and diseases of the digestive system, while skin diseases are common after anxiety disorders.

The findings suggest that mental disorders are antecedent risk factors of certain physical diseases in early life, but also vice versa, according to the researchers.

"Our results expand the relevance of mental disorders beyond mental to physical health care, and vice versa, supporting the concept of a more integrated mental-physical health care approach, and open new starting points for early disease prevention and better treatments, with relevance for various medical disciplines," the study said.

The research group led by Marion Tegethoff in collaboration with Professor Gunther Meinlschmidt from the University of Basel in Switzerland examined the temporal pattern and relationship between physical diseases and mental disorders in children and young people. 

They analysed data from a representative sample of 6,483 teenagers from the US aged between 13 and 18.

The researchers noted that some physical diseases tend to occur more frequently in children and adolescents if they have previously suffered from certain mental disorders. 

Likewise, certain mental disorders tend to occur more frequently after the onset of particular physical diseases.

Affective disorders such as depression were frequently followed by arthritis and diseases of the digestive system, while the same relationship existed between anxiety disorders and skin diseases, showed the study published in the journal PLOS ONE.

Anxiety disorders were more common if the person had already suffered from heart disease. A close association was also established for the first time between epileptic disorders and subsequent eating disorders.

The results offer important insights into the causal relationship between mental disorders and physical diseases.

​New York, Nov 25 (IANS) Taking a step further in identifying a possible therapy for the Zika infection, researchers have discovered the mechanism by which a human antibody previously identified to react with the Dengue virus, prevents Zika infection at a cellular level.

Previously, the antibody C10 was identified as one of the most potent antibodies able to neutralise Zika infection. The new study, published in the journal Nature Communications, determines how C10 prevents the infection.

"By defining the structural basis for neutralization, these studies provide further support for the idea that this antibody will protect against Zika infection, potentially leading to a new therapy to treat this dreaded disease," said Ralph Baric, Professor at University of North Carolina.

To infect a cell, virus particles usually undergo two main steps, docking and fusion, which are also common targets for disruption when developing viral therapeutics. 

During docking, the virus particle identifies specific sites on the cell and binds to them. With Zika infection, docking then initiates the cell to take the virus in via an endosome -- a separate compartment within the cell body. 

Proteins within the virus coat undergo structural changes to fuse with the membrane of the endosome, thereby releasing the virus genome into the cell, and completing the fusion step of infection.

Using a method called cryoelectron microscopy, which allows for the visualisation of extremely small particles and their interactions, the team visualised C10 interacting with the Zika virus under different pHs (potential of hydrogen, a scale of acidity), so as to mimic the different environments both the antibody and virus will find themselves in throughout infection. 

They showed that C10 binds to the main protein that makes up the Zika virus coat, regardless of pH, and locks these proteins into place, preventing the structural changes required for the fusion step of infection. 

Without fusion of the virus to the endosome, viral DNA is prevented from entering the cell, and infection is thwarted.

"Hopefully, these results will further accelerate the development of C10 as a Zika therapy to combat its effects of microcephaly (a birth defect) and Guillain-Barre (paralysis) syndrome," one of the researchers Lok Shee-Mei from Duke-National University of Singapore Medical School in Singapore.