Knowledge Update

New York, Dec 20 (IANS) Using a gene-editing technology, scientists have identified three human genes essential for HIV infection, a finding that may promise new targets for treatment of the deadly infection.

HIV virus has only nine genes, while humans have more than 19,000. Thus, viruses take control of human genes to make essential building blocks for their replication, the study said. 

The study focussed on human immune cells T cells, the primary targets of HIV, and to identify host genes with the most dramatic role in viral infection of T cells.

"Our goal was to identify human genes, also called host genes, that are essential for HIV to replicate but could be eliminated without harming a human patient," said Bruce Walker, Professor at Harvard Medical School in Boston, US.

In the study, using CRISPR to screen a cell line derived from HIV-susceptible CD4 T cells, the scientists identified five genes that, when inactivated, protected cells from HIV infection without affecting cellular survival. 

In addition to CD4 and CCR5, the screen identified genes for two enzymes -- TPST2 and SLC35B2 -- that modify the CCR5 molecule in a way that is required for the binding of HIV. 

An additional gene identified through the screen was ALCAM, which is involved in cell-to-cell adhesion. When CD4 T cells are exposed to low amounts of virus, as might be seen in natural transmission, loss of ALCAM was associated with striking protection from HIV infection.

The study demonstrates how CRISPR-based screens can be applied to identify host factors critical to the survival of other viral pathogens but dispensable for host cell viability. 

"CRISPR makes it possible to completely knock out genes at the DNA level; and our genome-wide, CRISPR-Cas9-based approach targets more than 18,500 genes, the vast majority of human protein-coding genes," explained Tim Wang, doctoral student at Whitehead Institute for Biomedical Research -- a non-profit research institution in Massachusetts, US. 

The study was published in the journal Nature Genetics.

​London, Dec 20 (IANS) Noise sensitivity in individuals may be caused by alterations in the brain functions linked with sound processing, a study has found.

The study, led by researchers from University of Helsinki in Finland showed that noise sensitivity is associated with functional alteration of auditory stimulus encoding and discrimination of noisy sounds.

The auditory system of noise sensitive individuals is less responsive to new sound features introduced among repetitive sounds, especially if the novel sound is noisier than the rest.

This finding suggests that it may be harder for sensitive people to build a prediction about changes in a varying soundscape and their auditory system might "tune down" its responsiveness to sounds in order to protect itself from overreacting to noise, the researchers observed.

"The study advances the view on noise sensitivity being more than just a negative attitude to sounds and brings us new information on the physiology of environmental sensitivity," said lead author Marina Kliuchko, doctoral student at the University of Helsinki.

The findings also showed that those who are noise sensitive are more likely to experience negative emotions from unwanted sounds and they show greater susceptibility to adverse effects of noise on health.

According to previous studies, such individuals are more prone to negative effects of noise on health, such as sleep disturbance and heart diseases and the reason that they are so sensitive to noise may be because of one's genetic profile.

The researchers hope that their work will highlight that noise sensitivity is an important issue to be recognised in planning noise control in living and working environments.

"We need further studies to conclude whether we've discovered something that is the reason why people are noise sensitive or is it the result of the brain's contractions against excessive noise," Kliuchko added.

The study appeared in the journal Scientific Reports.

​New York, Dec 20 (IANS) Researchers, including one of Indian-origin, have developed an oral vaccine against Salmonella -- the bacteria responsible for one of the most common food-borne illnesses in the world.

Most people infected with Salmonella bacteria develop diarrohea, fever, and abdominal cramps between 12 and 72 hours after infection, according to the US Centers for Disease Control and Prevention.

"In the current study, we analysed the immune responses of mice that received the vaccination by mouth as well as how they responded to a lethal dose of salmonella," said Ashok Chopra, Professor at University of Texas Medical Branch at Galveston.

"We found that the orally administered vaccines produced strong immunity against salmonella, showing their potential for future use in people," Chopra noted.

Currently, antibiotics are the first choice in treating salmonella infections, but the fact that some strains of salmonella are quickly developing antibiotic resistance is a serious concern. 

In earlier studies, the researchers developed potential vaccines from three genetically mutated versions of the salmonella bacteria, that is Salmonella Typhimurium, that were shown to protect mice against a lethal dose of salmonella. 

In these studies, the vaccines were given as an injection.

However, oral vaccination is simplest and least invasive way to protect people against salmonella infection. 

Taking this vaccine by mouth also has the added advantage of using the same pathway that salmonella uses to wreak havoc on the digestive system.

The findings were detailed in an article published in the journal Frontiers in Cellular and Infection Microbiology.

​New Delhi, Dec 20 (IANS) A top scientist at National Physics Laboratory (NPL) here has said that industry should come forward to commercialise the concept of the hydroelectric cell as it has the potential to be a very cheap source of electricity.


The inventor of the cell that produces electricity from water, R.K. Kotnala, the Chief Scientist at NPL, urged industry leaders to come forward and help improve the workability of the cell, which, he said, can be a great source of green energy. 

"It is a portable source of electricity as it can be used as a dry cell (like the common battery used in torches, remotes). And once it goes into production, will be cheaper than solar energy," Kotnala told IANS in an interview. 

"In case of wind energy, electricity can be produced using local sources only, plus a single windmill won't do, you have to build a series, which is very expensive. None of these factors can be a hindrance with the hydroelectricity cell," he added. 

He said that there is no potential harm from the battery upon disposal as no chemicals are used in its making. 

A team led by Kotnala proved the workability of producing electricity from water at room temperature without the use of any chemicals after working on it for 13 years. 

"We spent the first 11 years in working out the principle of the technology, and two years on building the device," Kotnala said. 

The results were published in the International Journal of Energy Research (IJER) in June this year under the title "Green Hydroelectrical Energy Source Based on Water Dissociation by Nano-porous Ferrite". 

The team used nano-porous magnesium ferrite to split water into hydronium (H3O) and hydroxide (OH) ions spontaneously, and silver and zinc as electrodes to make a cell that produces electricity. 

Using magnesium ferrite which was two inches in diametre, they were able to produce current of 86-110 milli-ampere and voltage of 0.9 volts, which is enough to charge a small plastic fan or an LED bulb of one watt. 

"For the last 70 years, research was going on around the world on how to dissociate water molecules to create energy, but we were the first ones to do it," Kotnala said, adding that all the components and raw materials were from India. 

The path-breaking work done by Kotnala straddles three different disciplines of science -- chemistry, physics and material science -- and can be claimed to be the biggest breakthrough in the world of batteries since 1980, when the working principle for the lithium-ion battery was demonstrated by scientist John Bannister Goodenough. 

The lithium-ion battery was commercialised by Sony in 1991 and since then has become the indispensable innard of every consumer-electronic device, laptop, smart-phone, DSLR, etc. 

Kotnala, whose research experience spans 32 years, most of it on solar cells, is proud of the fact that the whole enterprise was an Indian affair from the beginning. He also said that it has a strong chance of revolutionalising the green energy field at a time nations around the globe are trying to find means to curtail their carbon-footprints. 

He also admitted the limitations of the prototype cell and added that the most important thing was that it worked in principle, and the concept now can be made refined by degrees. 

"Since we can muster just so many resources at the lab, the model is not devoid of limitations. But that can be addressed once we have the right backing," he added.

​New York, Dec 19 (IANS) Researchers have developed a simple brain test that can potentially be used on a three-year-old to determine whether he or she is likely to grow up to become a criminal.

In the study, neuro-scientists at Duke University followed more than 1,000 children of pre-school age until they were 38, to find out if it was possible to predict who would go on to lead troubled lives.

The study showed that those with the lowest scores (20 per cent) went on to commit more than 80 per cent of crimes as adults.

The test found that these children began their lives with mild problems with brain function and brain health.

Growing up in a socio-economically deprived family, exposure to maltreatment, low intelligence quotient (IQ) and poor self-control were identified as the risk factors that can cause poor outcomes in adults, the researchers said.

In the study, the researchers tested the 'Pareto principle' -- also known as the '80-20 rule' -- which states that in the majority of systems, around 80 per cent of the effects come from about 20 per cent of the causes.

This principle, which worked in the field of computer science, biology, physics, economics, was also found to be true for societal burden.

By assessing a child's history -- beginning at age three -- of disadvantage, and particularly their brain health, one can predict where he or she might end up.

"Being able to predict which children will struggle is an opportunity to intervene in their lives very early to attempt to change their trajectories, for everyone's benefit and could bring big returns on investment for government," Terrie Moffitt, Professor at Duke University in North Carolina, was quoted as saying to the Telegraph.co.uk.

If problematic children could be targeted early, society could benefit hugely in the long term, the researchers noted in the study published in the journal Nature Human Behaviour.

​New York, Dec 19 (IANS) Bad bosses who play a significant role in increasing stress for employees, may be of two types -- 'dark' who have destructive behaviours or 'dysfunctional' who are not very good at their job, researchers have found.

"Dysfunctional bosses don't want to hurt you. Through lack of skill, or other personality defects, they're just not very good at their job. Largely, that's what we would call 'dysfunctional'," said Seth M. Spain from Binghamton University in New York, US.

Dark bosses, on the other hand, have destructive behaviours and hurt others to elevate themselves, Spain said.

These bosses are looked at through the three characteristics called the "Dark Triad", which includes Machiavellianism, narcissism and psychopathy.

"Dark bosses are people who enjoy the pain and suffering of others -- they're going to be mean, abusive and harassing in daily life," Spain added.

Team leaders can act as a lens through which people tend to view their work experience. Thus such bosses -- dysfunctional or dark -- can cause a great deal of stress to employees, the study observed.

The study, which looks to establish a taxonomy for identifying bad bosses and their distinct behaviours, can help fixing them and ultimately reduce stress in the workplace.

"We believe that these characteristics are extremely important for understanding employee development and career advancement," Spain noted.

The study was published in the journal Research in Occupational Stress and Well-Being.

​London, Dec 19 (IANS) Bullying affects men and women differently. Whereas it often causes women to go on prolonged sick leave or use antidepressants, men often choose to leave the labour market altogether for a period of time, a new research has found.

The researchers said it was a surprise to learn that bullying does not seem to increase men's sickness absence.

"In fact, it seems that men who are bullied are more likely than women to go to work even though they are actually sick," said Tine Mundbjerg Eriksen, Assistant Professor at School of Business and Social Sciences, Aarhus University in Denmark.

"At the same time, it appears that bullying affects men's salary level negatively, which indicates that the bullying hampers their opportunities for pay increases and promotions," she said.

One way of bullying is that your colleagues or your boss impede your ability to do your job properly, make changes to your work or hand the fun and important tasks to others, she explained.

In the study involving over 3,000 people in both public and private organisations, seven per cent of the respondents reported that they were being subjected to bullying. Of these, 43 per cent were men.

When it comes to the type and frequency of bullying, the research, published in the journal of Labour Economics, showed that men are just as exposed to work or personal-related bullying as women, but are actually slightly more exposed to physical intimidation than women.

"The million-dollar question is why men primarily react by leaving the workplace, while women react to bullying by taking prolonged sick leaves. If anything, this illustrates that men and women handle bullying differently," Eriksen said.

New York, Dec 19 (IANS) Rapid population decline among vertebrates began at the end of the 19th century when industrialisation was at its peak, leading to profound change in global living ecosystems, says a study.

"Industrialisation is the most natural explanation as to why we have rapid population decline in that period of time. It has to be somehow caused by human impact," said Yun-Xin Fu, Professor at University of Texas School of Public Health at Houston, US.

The current rate of species extinction is approximately 1,000 times the background rate of extinction and is attributable to human impact, ecological and demographic fluctuations, and inbreeding due to small population sizes. 

The researchers believe that the rate and the initiation date of rapid population decline can provide important clues about the driving forces of population decline in threatened species, but they are generally unknown

So the team reviewed thousands of scientific articles about the genetic diversity of vertebrate species. 

Their efforts yielded genetic data from 2,764 vertebrate species, 600 of which are endangered.

The researchers used a population genetics approach to model when each threatened species began to rapidly decline in population size. 

On average, the population size of endangered species declined by about 25 per cent every 10 years starting 123 years ago, said the study published in the journal Proceedings of the National Academy of Sciences.

​Washington, Dec 18 (IANS) Scientists have claimed to figured out how the world's biggest and most-valuable diamonds formed, media reported on Sunday.

In a study published this week in the US journal Science, the scientists said large gem-quality diamonds, like the world-famous Cullinan or Lesotho Promise, may be born in metallic liquid deep inside the Earth's mantle, Xinhua news agency reported.

The research team, led by Evan Smith of the Gemological Institute of America, reached the conclusion after examining so-called "offcuts" of massive diamonds, which are the pieces left over after the gem's facets are cut for maximum sparkle.

They found tiny metallic grains trapped inside in more than 30 exceptionally large stones, which are made up of a mixture of metallic iron and nickel, along with carbon, sulfur, methane, and hydrogen.

These inclusions led the researchers to conclude that these diamonds formed, like all diamonds, in the Earth's mantle, but they did so under conditions in which they were saturated by liquid metal.

Most diamonds formed at depths of 150 to 200 km under the continents and shoot to the surface in volcanic eruptions.

"Pure carbon crystallised in this mix of molten metallic liquid in Earth's deep mantle to form diamonds," the team explained in a statement.

"Small droplets of this metallic liquid were occasionally trapped within the diamonds as they grew," offering useful clues that may help "advance our understanding of Earth's deep mantle, hidden beneath tectonic plates and largely inaccessible for scientific observation," the statement added.

The findings may tell scientists about oxygen availability in different parts of the mantle.

Near the surface, the mantle chemistry is more oxidized, which scientists can tell from the presence of carbon in the form of carbon dioxide in magmas erupted in volcanoes.

"Previous experiments and theory predicted for many years that parts of the deep mantle below about 250 km depth contain small amounts of metallic iron and have limited available oxygen," Smith said.

Sydney, Dec 18 (IANS) People who leave school without a school certificate are more than twice as likely to have a heart attack as those with a university degree, researchers said.