Monday, February 20, 2023

Study shows long-term trend of undocumented Mexican immigrants most at risk for deportation from U.S.

No matter the U.S. political climate, young, single and less educated men seemed to be at higher risk for deportation than other undocumented Mexican immigrants from 2001 to 2019, a study led by Emory University finds. 

The Proceedings of the National Academy of Sciences (PNAS) published the study analyzing deportation and voluntary return migration data encompassing the administrations of U.S. Presidents George W. Bush, Barack Obama and Donald Trump. 

“Even through the Trump administration’s anti-immigrant rhetoric advocated deporting all undocumented immigrants, particularly from Mexico, the characteristics of Mexican immigrants deported during the Trump years were not dramatically different from previous administrations,” says Heeju Sohn, Emory assistant professor of sociology and lead author of the study. 

Co-authors include Anne Pebley and Amanda Landrian Gonzalez from the University of California Los Angeles and Noreen Goldman of Princeton University. 

The researchers examined trends in socio-demographic characteristics of undocumented Mexican immigrants deported by the U.S. along with those who chose to return to Mexico. 

While the study does not predict or offer any absolute probabilities, it provides insight into relative potential risks. 

On average, each administration annually deported about 893,000 people with the majority of them Mexican citizens. 

“Despite each administration’s differing approach and rhetoric, who was actually being deported or deciding to leave didn’t change all that much,” Sohn said. “Just because an undocumented person voluntary leaves the U.S. doesn’t always mean they felt they had a choice in that decision either.” 

Fewer immigrants were deported annually during the Trump administration than under Obama or Bush who had the highest number of deportations. During Obama’s first term, there was an increase in deportation of Mexican immigrants with criminal convictions but that percentage decreased in the last two years of his presidency. 

While Trump’s administration prioritized all undocumented immigrants for deportation, the result shows deportation focused more on young adults and those with less education, groups which already face higher deportation risks. 

"Policy makers and the public need to understand the consequences of the immigration policies that are implemented – whether they work or not,” says Pebley, a UCLA California Center for Population Research faculty fellow. “While the Trump administration's anti-immigrant rhetoric and policies had many negative effects on immigrants and Americans, they did not do what they were apparently intended to in terms of deporting a larger and more diverse group of undocumented immigrants.” 

The Trump administration’s anti-immigrant rhetoric and heightened enforcement didn’t appear to motivate a more diverse group of undocumented immigrants to leave voluntarily. Rather, voluntary return migration to Mexico was a trend that began early in the Obama administration after the great recession of 2007-2009, according to the study. 

“People who are leaving or being deported do not exist in a vacuum,” Sohn says. “You can’t isolate them separately from the social and family connections they have interwoven in U.S. society. So, what happens to undocumented people that society has neglected has a direct effect on the well-being of U.S. citizens. We have a duty to not discriminate and there is a need for additional research.” 

The experiences of undocumented children living in the U.S. is a blind spot in national data; the youngest age group in this study is 18 to 31. 

“Moving across countries is a disruptive life event,” Sohn says. “This is an age group where people take major steps as adults—finding a partner, having children or establishing a career. This can have reverberating consequences for the rest of their lives.” 

For the study, Sohn and the other researchers combined deportees’ and voluntary returnees’ data from both sides of the border—the Migration Survey on the Borders of Mexico-North (EMIF-N) and U.S. Current Population Survey’s Annual Social and Economic Supplement (ASEC). It’s the first time these two major sets of data were combined for research purposes and studied in a novel way. 

“It was critical that we understood the nuances of the data and sampling strategy. We took a lot of timand effort making sure our method accounted for the differences,” Sohn says. 

“This is part of a bigger desire to make sure the lives of underrepresented groups have adequate representation,” she adds. “A lot of the research in social sciences are based on large data sets that don’t put much focus on the smaller groups or ones that are harder to measure. I hope getting this important topic published will get visibility to a wider audience.” 

Funding for the story was provided by the NIH Eunice Kennedy Shriver National Institute of Child Health and Human Development (ROOHDO96322).

Genomic study reveals signs of TB adaptation in ancient Andeans

"Human-pathogen co-evolution is an understudied area that has a huge bearing on modern-day public health," says Sophie Joseph, first author of the study and an Emory graduate student in anthropology.

By Carol Clark

People have inhabited the Andes mountains of South America for more than 9,000 years, adapting to the scarce oxygen available at high altitudes, along with cold temperatures and intense ultraviolet radiation. A new genomic study suggests that Indigenous populations in present-day Ecuador also adapted to the tuberculosis bacterium, thousands of years before the arrival of Europeans. 

The journal iScience published the findings, led by scientists at Emory University. 

“We found that selection for genes involved in TB-response pathways started to uptick a little over 3,000 years ago,” says Sophie Joseph, first author of the paper and an Emory graduate student in anthropology. “That’s an interesting time because it was when agriculture began proliferating in the region. The development of agriculture leads to more densely populated societies that are better at spreading a respiratory pathogen like TB.” 

The investigators had originally set out to investigate how the Indigenous people of Ecuador adapted to living at high altitude. 

“We were surprised to find that the strongest genetic signals of positive selection were not associated with high altitude but for the immune response to tuberculosis,” says John Lindo, Emory assistant professor of anthropology and senior author of the study. “Our results bring up more questions regarding the prevalence of tuberculosis in the Andes prior to European contact.” 

The Lindo lab specializes in mapping little-explored human lineages of the Americas. 

Previously published research found evidence of the tuberculosis bacterium in the skeletal material of 1,400-year-old Andean mummies, contradicting some theories that TB did not exist in South America until the arrival of Europeans 500 years ago. 

The current paper provides the first evidence for a human immune-system response to TB in ancient Andeans and gives clues to when and how their genomes may have adapted to that exposure. 

A graphic from the iScience paper

“Human-pathogen co-evolution is an understudied area that has a huge bearing on modern-day public health,” Joseph says. “Understanding how pathogens and humans have been linked and affecting each other over time may give insights into novel treatments for any number of infectious diseases.” 

Co-authors of the paper include scientists at Central University of Ecuador, Technical University of Manabi in Ecuador, University of Pavia in Italy, University of Iowa and Florida Atlantic University. 

The researchers sequenced whole genomes using blood samples from 15 present-day Indigenous individuals living at altitudes above 2,500 meters in several different Ecuadorian provinces. They performed a series of scans to look for signatures of positive selection for genes in their ancestral past. 

“Computational techniques for sequencing genomes and modeling ancestral selection keep improving,” Joseph says. “The genomes of people living today give us a window into the past.” 

Among the strongest signals detected were for biomarkers that are switched on in modern humans during an active TB infection. The researchers modeled the timing of selection for several of the genes involved in the TB-response pathways. 

Although they were not as strong as for exposure to TB, some signals were also detected for biomarkers related to adaptation to hypoxia, or low levels of oxygen in the blood that result from living at high altitude. 

Previous research has revealed stark differences in how high-altitude populations in Tibet, Ethiopia and the Peruvian Andes adapted to hypoxia. 

“For the Ecuadorean samples, we did see a couple of overlaps with studies from the Peruvian Andes in the overarching genes involved in the selection for hypoxia, although the variants were slightly different,” Joseph says. “To me, that suggests that there may have been independent adaptations within even small populations, at the community level. It shows the robustness of the genome to solve adaptive problems through different pathways.” 

Joseph plans a career focused on mapping ancestral data for Indigenous populations from the Americas. 

“South America has far fewer genomic studies and publications compared to Europe and I’d like to help close that gap,” she says. 

“I want to understand human evolution and health from an integrated biological perspective,” Joseph adds. “The genome can reveal many fascinating things and yet it is just one aspect of a human being. You also have to consider the environment and social-cultural aspects.” 


Genomic mapping of little-explored human lineages

Ancient DNA analyses add new complexity to South America settlement

 Ancient DNA from Sudan shines new light on Nile Valley past 

Thursday, February 9, 2023

Extracts from two wild plants inhibit COVID-19 virus, study finds

Emory graduate student Caitlin Risener, first author of the study, gathers tall goldenrod in the field in South Georgia. "When you collect a specimen yourself, and dry and preserve the samples, you get a personal connection," she says. (Photos by Tharanga Samarakoon)

By Carol Clark

Two common wild plants contain extracts that inhibit the ability of the virus that causes COVID-19 to infect living cells, an Emory University study finds. Scientific Reports published the results — the first major screening of botanical extracts to search for potency against the SARS-CoV-2 virus. 

In laboratory dish tests, extracts from the flowers of tall goldenrod (Solidago altissima) and the rhizomes of the eagle fern (Pteridium aquilinum) each blocked SARS-CoV-2 from entering human cells. 

The active compounds are only present in miniscule quantities in the plants. It would be ineffective, and potentially dangerous, for people to attempt to treat themselves with them, the researchers stress. In fact, the eagle fern is known to be toxic, they warn. 

“It’s very early in the process, but we’re working to identify, isolate and scale up the molecules from the extracts that showed activity against the virus,” says Cassandra Quave, senior author of the study and associate professor in Emory School of Medicine’s Department of Dermatology and the Center for the Study of Human Health. “Once we have isolated the active ingredients, we plan to further test for their safety and for their long-range potential as medicines against COVID-19.” 

A powerful tool for drug discovery 

Quave is an ethnobotanist, studying how traditional people have used plants for medicine to identify promising new candidates for modern-day drugs. Her lab curates the Quave Natural Product Library, which contains thousands of botanical and fungal natural products extracted from plants collected at sites around the world. 

Tall goldenrod

Caitlin Risener, a PhD candidate in Emory’s Molecular and Systems Pharmacology graduate program and the Center for the Study of Human Health, is first author of the current paper. 

In previous research to identify potential molecules for the treatment of drug-resistant bacterial infections, the Quave lab focused on plants that traditional people had used to treat skin inflammation. 

Given that COVID-19 is a newly emerged disease, the researchers took a broader approach. They devised a method to rapidly test more than 1,800 extracts and 18 compounds from the Quave Natural Product Library for activity against SARS-CoV-2. 

“We’ve shown that our natural products library is a powerful tool to help search for potential therapeutics for an emerging disease,” Risener says. “Other researchers can adapt our screening method to search for other novel compounds within plants and fungi that may lead to new drugs to treat a range of pathogens.” 

Picking the locks on a cell’s surface 

SARS-CoV-2 is an RNA virus with a spike protein that can bind to a protein called ACE2 on host cells. “The viral spike protein uses the ACE2 protein almost like a key going into a lock, enabling the virus to break into a cell and infect it,” Quave explains. 

The researchers devised experiments with virus-like particles, or VLPs, of SARS-CoV-2, and cells programmed to overexpress ACE2 on their surface. The VLPs were stripped of the genetic information needed to cause a COVID-19 infection. Instead, if a VLP managed to bind to an ACE2 protein and enter a cell, it was programmed to hijack the cell’s machinery to activate a fluorescent green protein. 

A plant extract was added to the cells in a petri dish before introducing the viral particles. By shining a fluorescent light on the dish, they could quickly determine whether the viral particles had managed to enter the cells and activate the green protein. 

The researchers identified a handful of hits for extracts that protected against viral entry and then homed in on the ones showing the strongest activity: Tall goldenrod and eagle fern. Both plant species are native to North America and are known for traditional medicinal uses by Native Americans. 

Additional experiments showed that the protective power of the plant extracts worked across four variants of SARS-CoV-2: Alpha, theta, delta and gamma. 

Confirming the results with infectious virus 

To further test these results, the Quave lab collaborated with co-author Raymond Schinazi, Emory professor of pediatrics, director of Emory’s Division of Laboratory of Biochemical Pharmacology and co-director of the HIV Cure Scientific Working Group within the NIH-sponsored Emory University Center for AIDS Research. A world leader in antiviral development, Schinazi is best known for his pioneering work on breakthrough HIV drugs. 

The higher biosecurity rating of the Schinazi lab enabled the researchers to test the two plant extracts in experiments using infectious SARS-CoV-2 virus instead of VLPs. The results confirmed the ability of the tall goldenrod and eagle fern extracts to inhibit the ability of SARS-CoV-2 to bind to a living cell and infect it. 

“Our results set the stage for the future use of natural product libraries to find new tools or therapies against infectious diseases," Quave says. 

As a next step, the researchers are working to determine the exact mechanism that enables the two plant extracts to block binding to ACE2 proteins. 

A hands-on connection to nature 

For Risener, one of the best parts about the project is that she collected samples of tall goldenrod and eagle fern herself. In addition to gathering medicinal plants from around the globe, the Quave lab also makes field trips to the forests of the Joseph W. Jones Research Center in South Georgia. The Woodruff Foundation established the center to help conserve one of the last remnants of the unique longleaf pine ecosystem that once dominated the southeastern United States. 

“It’s awesome to go into nature to identify and dig up plants,” Risener says. “That’s something that few graduate students in pharmacology get to do. I’ll be covered in dirt from head to toe, kneeling on the ground and beaming with excitement and happiness.” 

She also assists in preparing the plant extracts and mounting the specimens for the Emory Herbarium. “When you collect a specimen yourself, and dry and preserve the samples, you get a personal connection,” she says. “It’s different from someone just handing you a vial of plant material in a lab and saying, ‘Analyze this.’” 

After graduating, Risener hopes for a career in outreach and education for science policy surrounding research into natural compounds. A few of the more famous medicines derived from botanicals include aspirin (from the willow tree), penicillin (from fungi) and the cancer therapy Taxol (from the yew tree). 

“Plants have such chemical complexity that humans probably couldn’t dream up all the botanical compounds that are waiting to be discovered,” Risener says. “The vast medicinal potential of plants highlights the importance of preserving ecosystems.” 

Co-authors of the current paper include: Sumin Woo, Tharanga Samarakoon, Marco Caputo and Emily Edwards (the Quave lab and Emory’s Center for the Study of Human Health); Keivan Zandi, Shu Ling Goh and Jessica Downs-Bowen (the Schinazi lab); Kier Klepzig (Joseph W. Jones Research Center); and Wendy Applequist (Missouri Botanical Garden). 

Funding for the paper was provided by the Marcus Foundation, the NIH-funded Center for AIDS Research and the NIH National Center for Complementary and Integrative Health. 


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