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Toronto, May 7: Scientists have uncovered how bats can carry the MERS coronavirus without getting sick, shedding light on what triggers coronaviruses, including the one behind the COVID-19 pandemic, to jump to humans.

According to the study, published in the journal Scientific Reports, coronaviruses like the Middle East respiratory syndrome (MERS) virus, and the COVID19-causing SARS-CoV-2 virus, are thought to have originated in bats.

While these viruses can cause serious, and often fatal disease in people, bats seem unharmed, the researchers, including those from the University of Saskatchewan (USask) in Canada, said.

"The bats don't get rid of the virus and yet don't get sick. We wanted to understand why the MERS virus doesn't shut down the bat immune responses as it does in humans," said USask microbiologist Vikram Misra.

In the study, the scientists demonstrated that cells from an insect-eating brown bat can be persistently infected with MERS coronavirus for months, due to important adaptations from both the bat and the virus working together.

"Instead of killing bat cells as the virus does with human cells, the MERS coronavirus enters a long-term relationship with the host, maintained by the bat's unique 'super' immune system," said Misra, one of the study's co-authors.

"SARS-CoV-2 is thought to operate in the same way," he added.

Stresses on bats, such as wet markets, other diseases, and habitat loss, may have a role in coronavirus spilling over to other species, the study noted.

"When a bat experiences stress to their immune system, it disrupts this immune system-virus balance and allows the virus to multiply," Misra said.

The scientists, involved in the study, had earlier developed a potential treatment for MERS-CoV, and are currently working towards a vaccine against COVID-19.

While camels are the known intermediate hosts of MERS-CoV, they said bats are suspected to be the ancestral host.

There is no vaccine for either SARS-CoV-2 or MERS, the researchers noted.

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"We see that the MERS coronavirus can very quickly adapt itself to a particular niche, and although we do not completely understand what is going on, this demonstrates how coronaviruses are able to jump from species to species so effortlessly," said USask scientist Darryl Falzarano, who co-led the study.

According to Misra, coronaviruses rapidly adapt to the species they infect, but little is known on the molecular interactions of these viruses with their natural bat hosts.

An earlier study had shown that bat coronaviruses can persist in their natural bat host for at least four months of hibernation.

When exposed to the MERS virus, the researchers said, bat cells adapt, not by producing inflammation-causing proteins that are hallmarks of getting sick, but instead by maintaining a natural antiviral response.

On the contrary, they said this function shuts down in other species, including humans.

The MERS virus, the researchers said, also adapts to the bat host cells by very rapidly mutating one specific gene.

These adaptations, according to the study, result in the virus remaining long-term in the bat, but being rendered harmless until something like a disease, or other stressors, upsets this balance.

In future experiments, the scientists hope to understand how the bat-borne MERS virus adapts to infection and replication in human cells.

"This information may be critical for predicting the next bat virus that will cause a pandemic," Misra said.

Washington DC, Jun 8: Astronomers acting on a hunch have likely resolved a mystery about young, still-forming stars and regions rich in organic molecules closely surrounding some of them.

They used the National Science Foundation's Karl G Jansky Very Large Array (VLA) to reveal one such region that previously had eluded detection and that revelation answered a longstanding question.

The regions around the young protostars contain complex organic molecules which can further combine into prebiotic molecules that are the first steps on the road to life.

The regions, dubbed "hot corinos" by astronomers, are typically about the size of our solar system and are much warmer than their surroundings, though still quite cold by terrestrial standards.

The first hot corino was discovered in 2003 and only about a dozen have been found so far. Most of these are in binary systems, with two protostars forming simultaneously.

Astronomers have been puzzled by the fact that, in some of these binary systems, they found evidence for a hot corino around one of the protostars but not the other.

"Since the two stars are forming from the same molecular cloud and at the same time, it seemed strange that one would be surrounded by a dense region of complex organic molecules and the other wouldn't," said Cecilia Ceccarelli, of the Institute for Planetary Sciences and Astrophysics at the University of Grenoble (IPAG) in France.

The complex organic molecules were found by detecting specific radio frequencies, called spectral lines, emitted by the molecules. Those characteristic radio frequencies serve as "fingerprints" to identify the chemicals.

The astronomers noted that all the chemicals found in hot corinos had been found by detecting these "fingerprints" at radio frequencies corresponding to wavelengths of only a few millimetres.

"We know that dust blocks those wavelengths, so we decided to look for evidence of these chemicals at longer wavelengths that can easily pass through dust," said Claire Chandler of the National Radio Astronomy Observatory, and principal investigator on the project.

"It struck us that dust might be what was preventing us from detecting the molecules in one of the twin protostars," added Chandler.

The astronomers used the VLA to observe a pair of protostars called IRAS 4A, in a star-forming region about 1,000 light-years from Earth. They observed the pair at wavelengths of centimetres.

At those wavelengths, they sought radio emissions from methanol, CH3OH (wood alcohol, not for drinking). This was a pair in which one protostar clearly had a hot corino and the other did not, as seen using the much shorter wavelengths.

The result confirmed their hunch. "With the VLA, both protostars showed strong evidence of methanol surrounding them. This means that both protostars have hot corinos. The reason we did not see the one at shorter wavelengths was because of dust," said Marta de Simone, a graduate student at IPAG who led the data analysis for this object.

The astronomers cautioned that while both hot corinos now are known to contain methanol, there still may be some chemical differences between them. That, they said, can be settled by looking for other molecules at wavelengths not obscured by dust.

"This result tells us that using centimetre radio wavelengths is necessary to properly study hot corinos," Claudio Codella of Arcetri Astrophysical Observatory in Florence, Italy, said.

"In the future, planned new telescopes such as the next-generation VLA and SKA, will be very important to understanding these objects," added Codella.

New Delhi, Jan 25: The Patiala House court on Saturday started hearing a plea filed by the Nirbhaya convicts that alleged that the Tihar Jail administration have "not presented the papers on time".

The Public Prosecutor informed the court that Tihar Jail authorities have already supplied the relevant documents. He further informed that these are mere delaying tactics adopted by the convicts.

Advocate A.P. Singh, lawyer for three of the four death row convicts in the Nirbhaya gang-rape case had moved an application before the court seeking directions to the Tihar Jail authorities to supply him the relevant documents in order to exercise the remaining legal remedies available with the death row convicts -- Vinay Pawan and Akshay.

The Public Prosecutor also told the court that he spoke to the jail authorities over the phone and a report in this regard will be filed shortly as the jail officials were on their way to the court.

The judge demanded from the convicts lawyer to show what he has filed.

The convicts lawyer, A.P. Singh, said that he received some documents, but has still not been supplied with the personal diary of one of the convict -- Vinay Kumar Sharma and also the medical documents.

Judge then asked the lawyer to wait for until the report arrives form the Tihar Jail.

On this, the convicts lawyer said he was not questioning the intention of the jail. "I know the jail has been changed. It isn't there fault, too," he said.

The Public Prosecutor refuted the allegation saying that the defence counsel was trying to defeat the speed of law.

"We have supplied all the documents to the counsel. We have supplied all the documents except the painting and some other documents. We have nothing apart from that," public prosecutor said.

Singh, in his plea filed before the Patiala House Court sought urgent orders of the court in order to file a mercy petition of Vinay Sharma and in relation to requests for documents for convicts Vinay Sharma, Pawan Kumar Gupta and Akshay Kumar Singh.

He further said that the convicts undertook several steps to obtain relevant information necessary for filing the mercy petitions. In regular interval, the convicts requested the concerned authority to supply documents pertaining to their medical records from 2012 to 2015 and 2019-2020, records of cellular confinement, records of the amount earned in prison through labour, records of educational and reformative activities like Tihar Olympics and Painting, etc.

The Supreme court had recently dismissed the curative petition for the other two convicts -- Vinay Kumar Sharma (26) and Mukesh Singh (32).

The court had recently issued death warrant against the convicts and fixed 6 a.m. on February 1 as the date and time of execution of the death penalty.

The 23-year-old victim in the case was brutally gang raped and tortured on December 16, 2012, which later led to her death. All the six accused were arrested and charged with sexual assault and murder. One of the accused was a minor and appeared before a juvenile justice court, while another accused committed suicide in Tihar Jail.

Four of the convicts were sentenced to death by a trial court in September 2013, and the verdict was confirmed by the Delhi High Court in March 2014 and subsequently upheld by the Supreme Court in May 2017, which also dismissed their review petitions.

A Juvenile involved in the crime was convicted by a juvenile justice board and released from a reformation home after serving a three-year term.

Hearing in a different case, Chief Justice of India S.A. Bobde on Thursday said a condemned person cannot fight the death penalty endlessly and it was important for the capital punishment to reach its finality.

The death penalty, he noted, cannot be questioned at every turn by the convict.