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Pangolin, bat role in coronavirus path to humans remains unclear

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Armadillo-like animals called pangolins may have played a role in the emergence in humans of the new SARS-CoV-2 coronavirus, but they weren’t the only links in animal-to-human transmission, scientists say.

Pangolins are sold for food in live-animal “wet markets” in China — facilities that have long been suspected of being ground zero for the spread of viruses originating in animals to people.

Since the pandemic, experts worldwide have called for the closure of such markets in China and elsewhere.

Researchers at Duke University School of Medicine, Los Alamos National Laboratory in New Mexico, the University of Texas at El Paso and New York University are studying the virus that causes COVID-19, and their research sheds new light on how it was able to make the leap from animals to people.

By exchanging an essential fragment of a gene in the virus in pangolins, SARS-CoV-2 became able to make its move, the researchers concluded.

This species-to-species jump was made possible because the virus’ mutation allowed it to attach itself to human cells, like a key fitting into a lock, explain study co-author Dr. Feng Gao, a professor of medicine at Duke.

“Very much like the original SARS that jumped from bats to civets, or MERS that went from bats to dromedary camels, and then to humans, the progenitor of this pandemic coronavirus underwent evolutionary changes in its genetic material that enabled it to eventually infect humans,” Gao said in a Duke news release.

However, the pangolin coronaviruses sampled in their new study are just too dissimilar from SARS-CoV-2 to infect humans, so it’s possible that some intermediary species — not pangolins or bats — was involved in the process whereby SARS-CoV-2 acquired the ability to latch onto and infect human cells.

The new coronavirus uses a special structure on its outer coat to attach itself to human respiratory and intestinal cells, the researchers explained. This site is different from the one in infected bats, so bats weren’t the cause of the pandemic, they noted.

And “people had already looked at the coronavirus sequences sampled from pangolins that we discuss in our paper,” added co-researcher Elena Giorgi, a staff scientist at Los Alamos National Laboratory.

“However, the scientific community was still divided on whether they played a role in the evolution of SARS-CoV-2,” she said in the release.

SARS-CoV-2 appears to be a sort of hybrid strain, somewhere between the strains isolated from either pangolins or bats, the researchers said.

“In our study, we demonstrated that indeed SARS-CoV-2 has a rich evolutionary history that included a reshuffling of genetic material between bat and pangolin coronavirus before it acquired its ability to jump to humans,” Giorgi said.

Such “jumps” — and the pandemics they might cause — can be curbed in the future, however, the researchers stressed.

“While the direct reservoir of SARS-CoV-2 is still being sought, one thing is clear: reducing or eliminating direct human contact with wild animals is critical to preventing new coronavirus zoonosis in the future,” they concluded, including wet markets.

The report was published May 29 in the journal Science Advances.

More information

For more on COVID-19, see the U.S. Centers for Disease Control and Prevention.

Copyright 2020 HealthDay. All rights reserved.



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Researchers, growers seek vanilla production in Florida

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ORLANDO, Fla., Aug. 11 (UPI) — Growers and researchers in Florida hope the aromatic vanilla bean can provide a lucrative, high-margin crop for the state’s farmers.

The University of Florida is heading research into vanilla, which comes from a tropical orchid and carries a hefty price around the world.

The goal is to determine how well the plants grow in Florida’s subtropical climate, where the dominant crop — citrus — has suffered from destructive diseases and hurricanes that have shut groves and put growers out of business.

Already, the university reports that hobbyists, bakers and breweries are calling to line up more vanilla production.

“The interest in this as a new crop is huge,” said Alan Chambers, assistant professor of tropical plant genetics at the university’s research station south of Miami.

“Our biggest problem right now is growers can’t find enough plants. We have people calling and asking to buy the beans we’re growing, and we say you have to wait a couple of years.”

Chambers knows that vanilla can grow in Florida because four native species of the vanilla orchid plants exist, but none of the native types produces authentic vanilla.

So, he’s started with the most common commercial species, vanilla planifolia, the beans from which Madagascar and Mexico export in large quantities. Chambers has 150 of the plants ready to distribute to community center gardens and other growers as far north as Tampa.

Florida will never be able to compete globally for vanilla due to the cost of labor, but there’s a big demand for specialty vanilla, he said.

“We’d be looking at extremely high quality, similar to the limited vanilla production in Hawaii,” Chambers said. “We’re hearing from brewers, herbalists, bakers and aroma extractors.”

Chambers also helped a Miami area grower, attorney Abrahm Smith, obtain 800 of the vanilla plants for Smith’s small, 8-acre farm. They take up about one-quarter of an acre.

“It’s a hobby farm for me, but if vanilla works, it will be great because it has a very high-profit margin,” Smith said. “I should be able to make as much from that quarter-acre as I do from 6 acres of fruit trees we’ve planted.”

That high margin is what drove the crop to become one of Madagascar’s top exports, but the bean is not processed on the island. Much of the bean crop is processed when it reaches the United States, where it is primarily used as a food and drink flavoring.

The price of vanilla has fluctuated wildly in recent years with weather conditions in Madagascar, from $600 per 2.2 pounds of beans in 2018 to $350 for that amount in June.

The United States is the largest importer of vanilla beans. Given the high value of the crop, and Florida’s struggles with citrus, the University of Florida funded Chambers’ research with a $75,000 grant.

Chambers also advises a separate project led by private industry that collects funds from interested growers to provide thousands of the vanilla plants from a nursery in Orlando.



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Math models developed by Alan Turing help scientists explain bird behavior

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Aug. 11 (UPI) — In a new study, researchers in Britain used math models developed by famed mathematician Alan Turing to figure out why flocks of long-tailed tits separate themselves into different parts of their habitat.

Many birds form what are called home range patterns, but scientists have struggled to explain why non-territorial passerine segregate themselves.

For the study, scientists at the University of Sheffield tracked the movements of long-tailed tits across the woodlands they called home. After collecting enough data for patterns to emerge, researchers used Turing-inspired models to determine what causes the segregation.

The models deployed by Sheffield researchers were similar to those Turing developed to show how patterns in nature, like stripes of a zebra or a leopard’s spots, can emerge naturally from a uniform state.

The new analysis, published this week in the Journal of Animal Ecology, showed long-tailed tits, when segregating themselves across the landscape, were less likely to avoid places where they had previously interacted with relatives.

The passerine birds, however, were more likely to steer clear of places where they’d previously encountered larger flocks. The birds also showed a preference for the center of the woodlands.

“Mathematical models help us understand nature in an extraordinary amount of ways and our study is a fantastic example of this,” Sheffield doctoral student Natasha Ellison, lead author of the new study, said in a news release.

Scientists had previously used Turing models to understand the movement patterns and distribution of territorial animals, but this is the first time the same mathematical models have helped researchers understand the spacing and movements of a non-territorial species.

“Long-tailed tits are too small to be fitted with GPS trackers like larger animals, so researchers follow these tiny birds on foot, listening for bird calls and identifying birds with binoculars,” Ellison said.

“The field work is extremely time consuming and without the help of these mathematical models these behaviors wouldn’t have been discovered,” Ellison said.



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Increasing indigenous property rights could help save the rainforest

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Aug. 11 (UPI) — To protect the Amazonian rainforest, new research suggests full property rights for tribal lands be extended to Brazil’s indigenous communities.

For the study, researchers at the University California, San Diego, used satellite data of vegetation coverage in the Amazon rainforest to study deforestation patterns between 1982 and 2016. Scientists compared the results of their mapping efforts with Brazilian government records of indigenous property rights.

The analysis, detailed Tuesday in the journal Proceedings of the National Academy of Sciences, showed land owned fully and collectively by local tribes featured a 66 percent reduction in deforestation rates.

“Indigenous traditional land use, based on collective ownership, has been associated with the preservation of a land’s biodiversity,” researcher Kathryn Baragwanath, postdoctoral candidate in the political science department at UCSD, told UPI.

One study published earlier this year showed land stewardship by indigenous communities was associated with greater levels of carbon sequestration.

Baragwanath said these positive ecological impacts are strengthened when indigenous communities have the full scope of property rights and legal tools to defend tribal lands from commercial interests.

“These legal rights ensure that the boundaries can no longer be contested, the territory is registered in the national land registry, the government is constitutionally responsible for protecting the territories and the territorial resources are considered to belong to indigenous peoples,” she said.

When conducting their analysis, Baragwanath and researchers accounted for variables besides indigenous property rites — including proximity to roads, mining projects and rivers, elevation, population density and rainfall.

In Brazil, the process of gaining full property rights, called homologation, is complex — at least partially because government agencies there have been slow to review applications, researchers said.

Often, as the process plays out at a snail’s pace, commercial interests will start illegal mining or logging, so they can later argue that they’ve established “productive use of land,” researchers said.

To protect the Amazon and the region’s remaining forests, Baragwanath suggests Brazil’s government strengthen their environmental agencies.

“Public policy should focus on granting full property rights to the indigenous peoples who have not yet received their rights,” she said.



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