'How bats carry coronavirus without getting sick decoded'

News Network
May 7, 2020

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.

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Agencies
February 26,2020

Unnao, Feb 26: Ever heard of someone wishing a 'bright future' for the dead? In a bizarre incident in Uttar Pradesh's Unnao district, a village head issued a death certificate with the wish for an elderly man who had died last month.

The incident took place in the Sirwariya village in Asoha block where an elderly person Laxmi Shankar died after a prolonged illness on January 22.

His son went to the village head Babulal and requested him to issue a death certificate that he needed for some financial transactions.

Babulal not only issued the death certificate, but also 'wished' 'a bright future for the deceased' on the document.

The village head wrote in the death certificate -- "Main inke ujjwal bhavishya ki kaamna karta hoon (I wish him a bright future)."

The letter went viral on the social media on Monday after which the village head apologised for the error and issued a new death certificate.

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Agencies
May 30,2020

The GST Council is unlikely to make major changes in the indirect tax structure at its next meeting slated mid June.

A top government source said that the Centre is not in favour of increasing tax rates on any goods or service as it could further impact consumption and demand that is already suppressed due the COVID-19 pandemic and lockdown.

It was widely expected that the GST Council could consider raising tax rates and cess on certain non-essential items to boost revenue for states and the Centre. Several states have reportedly taken an over 80-90 per cent hit in GST collections in April, the official data for which has not yet been released by the Centre.

"The need of the hour is to boost consumption and improve demand. By categorising items into essential and non-essential and then raising taxes on non-essential is not what Centre favours. But, the issue on rates and relief will be decided by the GST Council that is meeting next month," the finance ministry official source quoted above said.

The GST Council is chaired by the Union finance minister and thus the views of the Centre play out strongly in the council meetings.

However, the Council will also have to balance the expectations of the states whose revenues have nosedived after the coronavirus outbreak and wide scale disruption to businesses while they have still not been paid GST compensation since the December-January period.

To the question of wider scale job losses in the period of lockdown as businesses get widely impacted, the official said that the Finance Ministry has asked the labour ministry to collect data on job losses during Covid-19 and is constantly engaging with the ministry to oversee job losses and salary cuts.

On restrictions put on Chinese investment in India, the official clarified that no decision had yet been taken to restrict China through the Foreign Portfolio Investment (FPI) route.

Asked about monetising government debt, the official said that the issue would be looked at when we reach a stage. It has not come to that stage yet.

In the government's over Rs 20 lakh crore economic package, the official defended its structure while suggesting that comparisons with the economic packages of other countries should not be drawn as India's needs were different from others.

"We have gone in more reforms that is needed to give strength to the economy. This is required more in our country," the official source said.

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Agencies
June 8,2020

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.

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