Tuesday, September 7, 2021

Left-wing authoritarians share key psychological traits with far right, Emory study finds

"Having clarity about the appeal of authoritarianism may be relevant to help better understand what's going on in the political landscape today," says Thomas Costello, an Emory graduate student of psychology and first author of the study.

By Carol Clark

People with extreme political views that favor authoritarianism — whether they are on the far left or the far right — have surprisingly similar behaviors and psychological characteristics, a new study finds. 

The Journal of Personality and Social Psychology published the research by psychologists at Emory University — the first comprehensive look at left-wing authoritarianism. 

“We took the long history of research into right-wing authoritarianism and used insights from that to develop a conceptional framework and measures to test for authoritarianism in the political left,” says Thomas Costello, an Emory PhD student of psychology and first author of the study. “We found that in terms of their psychological characteristics and their actual behaviors, left-wing authoritarians are extremely similar to authoritarians on the right.” 

Right-wing authoritarians tend to aggressively back the established hierarchy, while left-wing authoritarians tend to aggressively oppose it. They are almost like mirror images of one another that both share a common psychological core, the researchers conclude. 

“Authoritarians have a predisposition for liking sameness and opposing differences among people in their environment,” Costello says. “They are submissive to people they perceive as authority figures, they are dominant and aggressive towards people they disagree with, and they are careful to obey what they consider the norms for their respective groups.” 

At its core, authoritarianism is likely about power, Costello adds. 

“It’s a mistake to think of authoritarianism as a right-wing concept, as some researchers have in the past,” he says. “We found that ideology becomes secondary. Psychologically speaking, you’re an authoritarian first, and an ideologue only as it serves the power structure that you support.” 

Predicting political violence 

Another key finding is that authoritarianism from both ends of the spectrum is predictive of personal involvement in political violence. While left-wing authoritarianism predicts for political violence against the system in power, right-wing authoritarianism predicts for political violence in support of the system in power. 

Respondents to an online questionnaire who scored at the highest end of a one-to-seven scale for authoritarianism were two to three times more likely to report having engaged in political violence during the past five years. 

The good news is that both extreme authoritarianism and a tendency toward political violence appear relatively rare, Costello adds. Out of a sample size of 1,000 respondents, drawn from the online research tool Prolific and matched to the demographics of the U.S. population for age, race and sex, only 12 reported having engaged in political violence, and they all scored high for authoritarianism. 

“It’s clear that the loudest and most politically engaged segments of society have a big effect on our national discourse,” Costello says. “But there’s a big difference between criticizing those with opposing views and being willing to use violent force against people who disagree with you as a means of changing the status quo.” 

While an individual reporting that they had performed an act of violence was rare, nearly a third of respondents agreed with the statement that they wouldn’t mind if a politician that diametrically opposed their own political views was assassinated. “The higher a respondent ranked on the scale for either left-wing or right-wing authoritarianism, the more likely they were to agree with this statement,” Costello says. 

Understanding left-wing authoritarianism 

The psychological study of authoritarianism goes back to the 1930s, as social scientists tried to understand the psychological processes that made people more inclined to support the rise of fascism in Europe. The resulting Fascism Scale, developed to measure the strength of individuals’ support for far-right ideology, helped spawn the field of political psychology. 

The topic especially intrigued Costello, who plans a career in political psychology. He joined Emory to work with Emory psychologist Scott Lilienfeld — a leader in research at the interface of psychology, politics and the polarization of society — who passed away last year. Lilienfeld is senior author of the current paper. 

“As I began investigating the topic of authoritarianism, I found it puzzling that psychology researchers had almost exclusively looked at the concept from the perspective of the far right,” Costello says. “That makes it’s difficult to truly understand the psychology of authoritarianism and the conditions that can lead to its spread in a society.” 

For the current paper, the researchers developed a conceptual framework for left-wing authoritarianism, created measures for it, and then refined these measures after testing their validity through a series of studies across five community samples. 

In addition to the striking similarities between the two political extremes, the research also highlighted a key difference between the two: Left-wing authoritarians were more likely to perceive the world as a dangerous place and experience intense emotions and a sense of uncontrollability in response to stress. Right-wing authoritarians were more cognitively rigid, less open to new experiences, and less likely to believe in science. 

The research does not delineate the prevalence of authoritarianism in society. Like any other personality trait, authoritarianism lies on a spectrum with only a few at the extreme top-end of the scale, Costello says. 

“Our work should not be used as a political cudgel,” he stresses. “Instead it should be used as a piece of information to help us understand the pull of extremism and intolerance. Having clarity about the appeal of authoritarianism may be relevant to help better understand what’s going on in the political landscape today.” 

Co-authors of the paper include Shauna Bowes, an Emory graduate student of psychology; Irwin Waldman, Emory professor of psychology; Arber Tasimi, Emory assistant professor of psychology; and Sean Stevens, from New York University’s Department of Business and Society and the Foundation for Individual Rights in Education. The work was funded in part by the Institute for Humane Studies at George Mason University.

Related:

Scott Lilienfeld remembered for advancing psychology while embodying kindness

Emory psychologist examines whether 'intellectual humility' can temper political, religious polarization

Tuesday, August 31, 2021

Emora, the chatbot who cares for you

"We believe that Emora represents a groundbreaking moment for conversational artificial intelligence," says Jinho Choi, Emory associate professor of computer science.

A team of six Emory computer science students are helping to usher in a new era in artificial intelligence. They’ve developed a chatbot capable of making logical inferences that aims to hold deeper, more nuanced conversations with humans than have previously been possible. They’ve christened their chatbot “Emora,” because it sounds like a feminine version of “Emory” and is similar to a Hebrew word for an eloquent sage. 

The team is now refining their new approach to conversational AI — a logic-based framework for dialogue management that can be scaled to conduct real-life conversations. Their longer-term goal is to use Emora to assist first-year college students, helping them to navigate a new way of life, deal with day-to-day issues and guide them to proper human contacts and other resources when needed.

Eventually, they hope to further refine their chatbot — developed during the era of COVID-19 with the philosophy “Emora cares for you” — to assist people dealing with social isolation and other issues, including anxiety and depression. 
 
The Emory team is headed by graduate students Sarah Finch and James Finch, along with faculty advisor Jinho Choi, associate professor in the Department of Computer Sciences. The team also includes graduate student Han He and undergraduates Sophy Huang, Daniil Huryn and Mack Hutsell. All the students are members of Choi’s Natural Language Processing Research Laboratory.


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Tuesday, August 10, 2021

Diverse landcover boosts yields for major U.S. crops, study finds

"Landscape diversification appears to be an important piece for boosting our resilience to climate change, both as a country and at the farm scale," says Emily Burchfield, assistant professor of environmental sciences. 

By Carol Clark

Monoculture — or specializing in a single crop, covering larger fields, that can be harvested with bigger machines on a simplified landscape — is widely assumed to boost a farm’s production capacity. A major study encompassing the mainland United States, however, suggests that the opposite is true. 

Nature Food published the research. 

“We found that in more diverse systems, corn and wheat yields can be up to 10 percent higher,” says Emily Burchfield, assistant professor in Emory University’s Department of Environmental Sciences and co-author of the study. “And if you combine high diversity of landcover with more complex landscape configurations, corn and wheat yields increase by more than 20 percent.” 
 
Burchfield’s research combines spatial-temporal, social and environmental data to understand the future of food and water security in the United States and the consequences of a changing climate. She shares authorship of the Nature Food paper with Katherine Nelson, from the Department of Geography and Geospatial Sciences at Kansas State University. 

The research has major implications for helping farmers adapt to climate change. “Farming is already one of the toughest jobs on the planet,” Burchfield says. “And many people’s lives depend on a cropping system that likely won’t be sustainable 30 years from now. Landscape diversification appears to be an important piece for boosting our resilience to climate change, both as a country and at the farm scale, in terms of extreme weather events.” 

Agriculture has radically transformed Earth’s landscape, the authors note. Globally, agriculture encompasses a third of all ice-free land. In the United States, agriculture covers more than half of the land area, more than two-thirds of which is cultivated with the commodity crops of corn, wheat or soy. 

It’s well-established that diverse landscapes are associated with healthier ecosystems, benefiting pollination, water retention and soil quality — environmental factors that are also important to agriculture. Small, field-scale trials have suggested that adding diversity and complexity to landscapes, such as hedgerows or a strip of natural habitat within a field, may also benefit crop yields. 

For the current paper, the researchers examined how such diversity and complexity affects crop yields from a large-scale, national perspective. They drew from publicly accessible data, including the U.S. Department of Agriculture’s CropScape Data Layer, daily weather data from the PRISM Climate Group, and soil and landscape properties from the Natural Commodity Crop Productive Index. They integrated the data into an analytical computer model of crops and crop yields for 3,100 U.S. counties, covering the entire contiguous United States, for the period 2008 to 2018. 

They then used this model to test the impacts of diversity and complexity of landscapes on the yields of the major U.S. food crops of corn, wheat and soy. The researchers controlled for factors such as weather, soil quality, water access and market fluctuations. 

The results showed that increased landcover diversity is associated with increases for corn and wheat of more than 10 percent — an effect similar to the impact of seasonal rainfall and soil suitability. And landscape configurations that are both moderately complex and also highly diverse are associated with yield increases of more than 20 percent for corn and wheat. 

The researchers are now digging into how landscape diversity and complexity could best be applied at a regional scale. 

“The United States is huge and there can be no one-size fits all strategy,” Burchfield says. “We plan to zoom into different regions and look at the barriers and bridges to diversification for each region. We hope that our work can provide data-driven evidence to help farmers diversify their landscapes in intentional ways to boost their livelihoods and their resilience to climate change, while also supporting the resilience of ecosystems.” 

The research was funded in part by the U.S. Department of Agriculture National Institute of Food and Agriculture.

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Monday, August 9, 2021

EPA funds project to measure environmental contaminants, exposures in West Atlanta

The research project grew out of a 2018 discovery of high lead levels in the soil of some residences in West Atlanta by Eri Saikawa (above), associate professor in the Department of Environmental Sciences, and former student Sam Peters, who received a PhD from Rollins School of Public Health.

By Carol Clark

The Environmental Protection Agency awarded Emory University researchers $1.35 million to work with members of the West Atlanta community to better understand any potential risks in the area for exposures among children to lead and heavy metals and metalloids, along with other environmental contaminants. 

“This award helps researchers at Emory University develop approaches to advance research that will help protect our children,” says John Blevins, the EPA’s acting region four administrator. “This EPA-funded research will further our understanding of children’s chemical exposures and potential strategies to reduce their impact on children’s health.” 

“A key part of this project is strong engagement with the community,” says Eri Saikawa, associate professor in Emory’s Department of Environmental Sciences, who is the lead contact and co-principal investigator on the grant. She notes that the researchers will hold regular meetings with residents to learn their needs and concerns before testing for environmental contamination and exposures, and to communicate findings as the project proceeds. 

“We want to make sure that community members are not just subjects of the research but are involved in ways that help them benefit from the science,” Saikawa says. “Ultimately, we want to raise awareness of the community members and provide them with educational materials specific to their needs to help lower the risks of their families being exposed to toxicants. We also hope our data will help in the development of holistic regulatory frameworks to prevent exposures to environmental contaminants in underserved communities around the country.” 

Dana Barr, professor of environmental health in Emory’s Rollins School of Public Health, is co-principal investigator on the grant. Ziad Kazzi, associate professor in Emory Medical School’s Department of Emergency Medicine and an expert in medical toxicology, is a co-investigator. 

Historic Westside Gardens, made up of residents of the area, is a community partner for the project.

“This project is unique and important,” says Barr, who co-directs Rollins’ Laboratory for Exposure Assessment and Development in Environmental Research Lab (LEADER). “We’re not just analyzing environmental samples for toxicants, we’re also testing children for potential exposures and evaluating possible mitigation strategies. Our results will provide up-to-date information that is critical for the EPA to better regulate and mitigate the ongoing issue of environmental contaminants in urban areas.” 

“Good communication with our community partners is vital,” adds Kazzi. “As a physician specialized in toxicology, my main responsibility will be to answer any medical questions that may arise from community members and discuss their health concerns. We will also explain the science of environmental toxicants and help put our findings into context.” 

Emory research led to EPA investigation 

The health hazards of human exposures to heavy metals and metalloids — such as lead, cadmium, chromium and arsenic — are a globally recognized problem, and yet these hazards persist in many urban areas of the United States. Such contamination can accumulate through emissions from industry and power plants, the former use of lead in paint and gasoline, and through fertilizer, sewage sludge and pesticides. 

The community-based research project grew out of a 2018 discovery by Emory scientists of high lead levels in the soil of some residences of West Atlanta. Also known as the Westside, West Atlanta has a high poverty rate and is largely African American. Saikawa and Sam Peters, a PhD student at Rollins School of Public Health who has since graduated, were working with community members of Historic Westside Gardens to test their soil. 

The discovery of lead in some samples, along with deposits of slag — a waste byproduct of smelting and steel-making processes — led to a major EPA investigation and designation of parts of the area as a Superfund site. The EPA investigation now encompasses more than 2,000 properties. 

Issues of environmental justice 

Lead is a neurotoxicant that is especially harmful to children. Residents within the EPA investigation site, whose soil is found to be above the EPA threshold of 400 parts per million, are now able to have their soil removed and replaced for free, funded by Superfund appropriations. 

“This is an environmental justice issue,” Saikawa says. “Racial and class disparities for heavy metal and metalloid exposures are substantial, with African-Americans and the poor and the disenfranchised bearing the greatest risk.” 

Lead-exposure related cognitive impairments, she adds, are estimated to cost more than $50 billion annually in lost U.S. economic productivity. 

Expanded testing for harmful toxicants 

The new research project, funded by $1.35 million from the EPA’s Science to Achieve Results (STAR) program, will involve areas of the Westside outside of the current EPA investigation site. The research team plans to test the homes and yards of willing participants not just for heavy metals and metalloids but a total of 40 other organic and inorganic environmental toxicants. 

Young children may ingest significant quantities of soil and dust because they often play on the ground and put their hands and other objects into their mouths that can have dust or soil on them. Soil and dust ingestion can be a major route of exposure to chemicals such as lead, mercury, polychlorinated biphenyls (PCBs) and asbestos. 

The three-year project will also consider exposure pathways in addition to soil, such as household dust and paint. The team will seek to recruit 100 households to participate in environmental sampling. In addition, the team will seek parental permissions for 140 children ages six months to six years for biological samples of saliva, urine and blood, to test for exposures. 

Saikawa’s interdisciplinary research encompasses environmental health, atmospheric chemistry and environmental policy. She and her lab members will focus on recruiting participants, conducting surveys with community members, and gathering environmental samples of soil, household dust and paint chips. Her team will analyze these samples for heavy metals and metalloids, as well as modeling exposures from these various pathways. 

Barr’s lab will primarily focus on analyses of the biological and other environmental samples for a broader range of potential organic and inorganic toxicants. 

Kazzi, who specializes in the clinical assessment and management of toxicologic exposures, will help address health and medical concerns that may arise from the community. 

Emory is one of seven institutions across the United States that recently received STAR grants to help improve children’s health. The EPA’s STAR Program supports scientific research that advances EPA’s mission to protect human health and the environment. It is a competitive, peer-reviewed, extramural research program that provides access to the nation’s best scientists and engineers in academic and other nonprofit research institutions. 

“It is our duty to protect the health of those most vulnerable among us, including our children,” says Wayne Cascio, acting assistant administrator in EPA’s Office of Research and Development. “The researchers receiving these awards will improve our understanding of how children are exposed to chemicals, which will inform future actions to reduce these exposures and better protect their health.”

Related:

Emory soil analysis leads to EPA site investigation

Wednesday, July 21, 2021

Emory team makes finals in Amazon's Alexa Prize for artificial intelligence

The Emory team is led by faculty advisor Jinho Choi (center) and graduate students James Finch (left) and Sarah Finch.

A team of six Emory computer science students made it to the final round for Amazon’s Alexa Prize Socialbot Grand Challenge, a global competition among universities to create a chatbot that advances the field of artificial intelligence. The winner of the 2021 Alexa Prize will be announced in mid-August. At stake is a $500,000 first prize. In addition, $1 million in research funds will be awarded to the winning team if it meets the “grand challenge” criteria, including the ability of its chatbot to engage the judges in conversation for at least 20 minutes. 
 
In addition to Emory, the finalists are Czech Technical University, Prague; SUNY at Buffalo, New York; Stanford University and the University of California Santa Cruz. 
 
The Emory team is headed by graduate students Sarah Finch and James Finch, along with faculty advisor Jinho Choi, assistant professor in the Department of Computer Sciences. Last year, the trio headed a team of 14 Emory students that took first place, winning $500,000 for their chatbot named Emora. They chose the name because it sounds like a feminine version of “Emory” and is similar to a Hebrew word for an eloquent sage. 

This year, they are turning up the heat with an even more advanced version of Emora and new team members, including graduate student Han He and undergraduates Sophy Huang, Daniil Huryn and Mack Hutsell. All the students are members of Choi’s Natural Language Processing Research Laboratory

“I’m extremely proud to have such a talented team of students,” Choi says. “It’s a group of strongly motivated people with the right combination of diverse skills coming together at the right time. They’re working on changing the paradigm for conversational artificial intelligence.” 

“We’re using some established technology but taking a groundbreaking approach in how we combine and execute dialogue management so a computer can make logical inferences while conversing with a human,” adds Sarah Finch. “Ultimately, we’re making Emora even more flexible in how she can interact with people.”


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Monday, July 12, 2021

Using big data to zero in on a mosquito menace

"The ultimate goal is to give public health officials the power to do more effective and efficient mosquito control — even before an epidemic beings," says Gonzalo Vazquez-Prokopec, right, shown with public health technicians in Merida, Mexico.

Scientists from Emory University are leading a new strategy in humanity’s long-running war with the mosquito, using big data to target one species of this tiny disease vector. They have studied the behavior of the Aedes aegypti mosquito, pinpointing where it hangs out in homes. They are mapping cases over time of viral infections that this species can transmit when it bites a human — including dengue fever, Zika, chikungunya and yellow fever. They are zeroing in on high-risk neighborhoods for outbreaks of these diseases in sprawling urban areas of the tropics. 

“We’re working on some of the boldest and biggest changes in decades for the surveillance and control of this mosquito,” says Gonzalo Vazquez-Prokopec, associate professor in Emory's Department of Environmental Sciences
 
The National Institutes of Health’s Division of Microbiology and Infectious Diseases awarded Vazquez-Prokopec a $6.5 million grant to lead a consortium in a randomized clinical trial in Merida, Mexico, as part of the quest to reduce Aedes-borne viral infections. The trial is testing a novel intervention that previous Emory research finds promising: Indoor residual spraying of insecticide, targeted to the places in homes where this mosquito tends to rest. 
 

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Wednesday, July 7, 2021

Mapping dengue hot spots pinpoints risks for Zika and chikungunya

A female Aedes aegypti mosquito takes a blood meal from a human. "The ultimate goal is to give public health officials the power to harness big data and do more effective and efficient mosquito control — even before an epidemic begins," says Emory disease ecologist Gonzalo Vazquez-Prokopec. (Photo by James Gathany / CDC).

By Carol Clark

Data from nine cities in Mexico confirms that identifying dengue fever “hot spots” can provide a predictive map for future outbreaks of Zika and chikungunya. All three of these viral diseases are spread by the Aedes aegypti mosquito. 

Lancet Planetary Health published the research, led by Gonzalo Vazquez-Prokopec, associate professor in Emory University’s Department of Environmental Sciences. The study provides a risk-stratification method to more effectively guide the control of diseases spread by Aedes aegypti

“Our results can help public health officials to do targeted, proactive interventions for emerging Aedes-borne diseases,” Vazquez-Prokopec says. “We’re providing them with statistical frameworks in the form of maps to guide their actions.” 

The study encompassed data for 2008 through 2020 from cities in southern Mexico with a high burden of dengue fever cases during that period, along with cases of the more recently emerged diseases of Zika and chikungunya. The cities included Acapulco, Merida, Veracruz, Cancun, Tapachula, Villahermosa, Campeche, Iguala and Coatzacoalcos. 

The results found a 62 percent overlap of hot spots for dengue and Zika and 53 percent overlap for cases of dengue and chikungunya. In addition, dengue hot spots between 2008 and 2016 were significantly associated with dengue hotspots detected between 2017 and 2020 in five of the nine cities. 

The work builds on a previous study of the spatial-temporal overlap of the three diseases, focused on Merida, a city of one million located in the Yucatan Peninsula. That study showed that nearly half of Merida’s dengue cases from 2008 to 2015 were clustered in 27 percent of the city. These dengue hot spots contained 75 percent of the first chikungunya cases reported during the outbreak of that disease in 2015 and 100 percent of the first Zika cases reported during the Zika outbreak of 2016. 

“In this latest paper, we’ve expanded our analysis in scope and geography and shown that the findings are consistent across these nine cities of different sizes and in different regions,” Vazquez-Prokopec says. “We’ve confirmed that dengue, Zika and chikungunya outbreaks tend to concentrate in small areas of a city, and that these hot spots are predictive of where future cases will concentrate.” 

Mosquito control efforts generally involve outdoor spraying that covers broad swaths of a city, but the Aedes aegypti mosquito has adapted to live inside houses. Work by Vazquez-Prokopec and collaborators has shown that the best way to control these mosquitos and the diseases they spread is by spraying a long-lasting pesticide indoors — on the ceilings, along the bases of walls, and in other areas of homes where the mosquitos tend to cluster. This approach — known as targeted indoor residual spraying — is too expensive and time-consuming to apply across a city. 

The statistical framework in the current paper, however, allows public health officials to concentrate their efforts on previous hot spots for Aedes-borne diseases to better control — and even prevent — outbreaks. 

“The ultimate goal is to give public health officials the power to harness big data and do more effective and efficient mosquito control — even before an epidemic begins,” Vazquez-Prokopec says. 

Vazquez-Prokopec is currently leading a consortium in a randomized clinical trial in Merida to test targeted indoor residual spraying as an intervention against Aedes-borne diseases. The five-year trial, launched in 2020, is funded by a $6.5 million grant from the National Institutes of Health. 

Dengue fever is sometimes called “break-bone fever” due to the excruciating pain that is among its symptoms. More than one third of the world’s population lives in areas at high risk for infection with the dengue virus, a leading cause of illness and death in the tropics and subtropics. Dengue is endemic through most of Mexico, where between 75,000 and 355,000 cases occur annually, translating into an economic cost of between about U.S. $150 million and $257 million annually. 

Chikungunya is rarely fatal but the symptoms can be severe and debilitating. Zika can cause symptoms similar to those of dengue and chikungunya, such as joint pains and fever. While Zika tends to be less debilitating, or even asymptomatic, if a pregnant woman contracts the virus it can have a catastrophic impact on her unborn child, including severe brain defects. 

Co-authors of the Lancet Planetary Health paper include researchers from Mexico’s Ministry of Health; the Autonomous University of the Yucatan; the Autonomous University of Nuevo Leon; Yucatan Health Services; the Mexican Society of Public Health; the National Institute of Public Health in Cuernavaca; the Undersecretary of Prevention and Health Promotion in Mexico City; the Pan American Health Organization; and the U.S. Centers for Disease Control and Prevention. 

The work was funded by USAID, the U.S. Centers for Disease Control and Prevention, the Canadian Institute of Public Health, the state of Yucatan, the National Institutes of Health and Emory University.

Related:

Zeroing in on a mosquito menace

Contact tracing, with indoor spraying, can curb dengue outbreak

Wednesday, June 30, 2021

Genetic risks for nicotine dependence span a range of traits and diseases

"Genetic studies may help reduce some of the stigma society has against substance use disorders, while also making treatment more accessible," says Victoria Risner, first author of the new study on nicotine dependence, who did the work as an Emory undergraduate.

By Carol Clark 

Some people casually smoke cigarettes for a while and then stop without a problem, while others develop long-term, several packs-per-day habits. A complex mix of environmental, behavioral and genetic factors appear to raise this risk for nicotine dependence. 

Studies of groups of twins suggest that 40 to 70 percent of the risk factors are heritable. Until recently, however, studies have only explained about 1 percent of the observed variation in liability to nicotine dependence, using a genetic score based on how many cigarettes a person smokes per day. 

A study led by psychologists at Emory University offers a new model for examining this genetic risk. It leveraged genome wide association studies for a range of different traits and disorders correlated with nicotine dependence and explained 3.6 percent of the variation in nicotine dependence. 

The journal Nicotine & Tobacco Research published the finding. 

Higher polygenetic scores for a risk for schizophrenia, depression, neuroticism, self-reported risk-taking, a high body mass index, alcohol use disorder, along with a higher number of cigarettes smoked per day were all indicators of a higher risk for nicotine dependence, the study found. And polygenetic scores associated with higher education attainment lowered the risk for nicotine dependence, the results showed. 

“If you look at the joint effect of all of these characteristics, our model accounts for nearly 4 percent of the variation in nicotine dependence, or nearly four times as much as what we learn when relying solely on a genetic index for the number of cigarettes someone smokes daily,” says Rohan Palmer, senior author of the study and assistant professor in Emory’s Department of Psychology, where he heads the Behavioral Genetics of Addiction Laboratory. 

“What we’re finding,” Palmer adds, “is that to better leverage genetic information, we need to go beyond individual human traits and disorders and think about how risk for different behaviors and traits are interrelated. This broader approach can give us a much better measure for whether someone is at risk for a mental disorder, such as nicotine dependence.” 

Rohan Palmer heads the Department of Psychology's Behavioral Genetics of Addiction Laboratory that is developing new methods to better understand what makes people vulnerable to substance use disorders.

“All of the traits and diseases we looked at are polygenic, involving multiple genes,” adds Victoria Risner, first author of the study, who did the work as an Emory undergraduate majoring in neuroscience and behavioral biology. “That means that millions of genetic variants likely go into a complete picture for all of the heritable risks for nicotine dependence.” 

The researchers hope that others will build on their multi-trait, polygenetic model and continue to boost the understanding of the risk for such complex disorders. “The more we learn, the closer we can get to one day having a genetic test that clinicians can use to inform their assessment of someone’s risk for nicotine dependence,” Palmer says. 

Although the hazards of smoking are well established, about 14 percent of Americans report daily use of tobacco. Around 500,000 people die each year in the United States from smoking or exposure to smoke, and another 16 million live with serious illnesses caused by tobacco use, including cancer, cardiovascular disease and pulmonary disease. While the toxic chemicals produced during smoking and vaping are what cause harmful health effects, it’s the addictive component of nicotine that hooks people on these habits. 

Risner worked on the current paper for her honors thesis. “Nicotine dependence was interesting to me because the vaping scene was just arriving while I was an undergraduate,” she says. “I saw some of my own friends who were into vaping quickly becoming dependent on it, while some others who were using the same products didn’t. I was curious about the genetic underpinnings of this difference.” 

The project leveraged genome-wide association studies for a range of traits and disorders. The researchers then looked for matching variants in genetic data from a national representative sample of Americans diagnosed with nicotine dependence. The results showed how polygenetic scores for the different traits and disorders either raised or lowered the risk for that dependence. The number of cigarettes smoked per day, self-perceived risk-taking and educational attainment were the most robust predictors. 

The multi-variant, polygenetic model offers a road map for future studies. A clearer picture of heritability for nicotine dependence, for instance, may be gained by adding more risk associations to the model (such as nicotine metabolism) and clusters of polygenic traits (such as anxiety along with neuroticism). 

“As we continue to zero in on who is most at risk for becoming nicotine dependent, and what inter-related factors, whether genetic or environmental, may raise their risk, that could help determine what intervention might work best for an individual,” Palmer says. 

“Just a few decades ago, it was not well understood that nicotine dependence could have a genetic component,” Risner says. “Genetic studies may help reduce some of the stigma society has against substance use disorders, while also making treatment more accessible.” 

Risner graduated from Emory in 2019 and is now in medical school at the University of North Carolina, Chapel Hill. This summer, she’s applying the coding and analytical skills she learned at Emory to conduct research into genetic factors that may raise the risk for pre-term births. 

Emory co-authors of the Nicotine & Tobacco Research article include graduate student Lauren Bertin; post-doctoral fellow Chelsie Benca-Bachman; and Alicia Smith, associate professor in the School of Medicine. Additional authors include researchers from the University of Helsinki; Brown University; the Providence VA Medical Center; the Jackson Laboratory in Bar Harbor, Maine; Purdue University; and the University of Colorado at Boulder. 

The work on the Nicotine & Tobacco Research article was funded by the National Institute on Drug Abuse and the Academy of Finland.

Related:

Heritable traits that appear in teen years raise risk for adult cannabis use

New research aims to understand how genetic differences contribute to addiction

Monday, June 28, 2021

New molecule found in chestnut leaves disarms dangerous staph bacteria

"We're laying the groundwork for new strategies to fight bacterial infections at the clinical level," says Emory ethnobotanist Cassandra Quave, shown gathering samples of chestnut leaves in Italy. "We urgently need these new strategies."

By Carol Clark

Scientists isolated a molecule, extracted from the leaves of the European chestnut tree, with the power to neutralize dangerous, drug-resistant staph bacteria. Frontiers in Pharmacology published the finding, led by scientists at Emory University. 

The researchers dubbed the molecule Castaneroxy A, after the genus of the European chestnut, Castanea. The use of chestnut leaves in traditional folk remedies in rural Italy inspired the research. 

“We were able to isolate this molecule, new to science, that occurs only in very tiny quantities in the chestnut leaves,” says Cassandra Quave, senior author of the paper and associate professor in Emory’s Center for the Study of Human Health and the School of Medicine’s Department of Dermatology. “We also showed how it disarms Methicillin-resistant Staphylococcus aureus by knocking out the bacteria’s ability to produce toxins.” 

Methicillin-resistant Staphylococcus aureus (MRSA) causes infections that are difficult to treat due to its resistance to antibiotics. It is one of the most serious infectious disease concerns worldwide, labeled as a “serious threat” by the Centers for the Disease Control and Prevention. In the United States alone, nearly 3 million antibiotic-resistant infections occur each year, killing more than 35,000 people. 

Antibiotics work by killing staph bacteria, which can lead to greater resistance among those few bacteria that survive, spawning “super bugs.” The Quave lab has identified compounds from the Brazilian peppertree, in addition to the European chestnut tree, that simply neutralize the harmful effects of MRSA, allowing cells and tissue to naturally heal from an infection without boosting resistance. 

“We’re trying to fill the pipeline for antimicrobial drug discovery with compounds that work differently from traditional antibiotics,” Quave says. “We urgently need these new strategies.” She notes that antimicrobial infections kill an estimated 700,000 globally each year, and that number is expected to grow exponentially if new methods of treatment are not found. 

First author of the Frontiers in Pharmacology paper is Akram Salam, who did the research as a PhD student in the Quave lab through Emory’s Molecular Systems and Pharmacology Graduate Program.

The European chestnut, also known as the sweet chestnut, is native to Southern Europe and Asia Minor.

Quave is a medical ethnobotanist, researching traditional plant remedies to find promising leads for new drugs. Although many major drugs are plant-based, from aspirin (the bark of the willow tree) to Taxol (the bark of the Pacific yew tree), Quave is one of the few ethnobotanists with a focus on antibiotic resistance.

The story behind the current paper began more than a decade ago, when Quave and her colleagues researched written reports and conducted hundreds of field interviews among people in rural southern Italy. That pointed them to the European, or sweet, chestnut tree, native to Southern Europe and Asia Minor. “In Italian traditional medicine, a compress of the boiled leaves is applied to the skin to treat burns, rashes and infected wounds,” Quave says. 

Quave took specimens back to her lab for analysis. By 2015, her lab published the finding that an extract from the leaves disarms even the hyper-virulent MRSA strains capable of causing serious infections in healthy athletes. Experiments also showed the extract did not disturb normal, healthy bacteria on skin cells. 

Finally, the researchers demonstrated how the extract works, by inhibiting the ability of MRSA bacteria to communicate with one another, a process known as quorum sensing. MRSA uses this sensing signaling system to make toxins and ramp up its virulence. 

For the current paper, the researchers wanted to isolate these active ingredients from the plant extract. The process is painstaking when done manually, because plant extracts typically contain hundreds of different chemicals. Each chemical must be separated out and then tested for efficacy. Large scale fraction collectors, coupled to high-performance liquid chromatographic systems, automate this separation process, but they can cost tens of thousands of dollars and did not have all the features the Quave lab needed. 

Marco Caputo, a research specialist in the lab, solved the problem. Using a software device from a child’s toy, the LEGO MINDSTORMS robot creator, a few LEGO bricks, and some components from a hardware store, Caputo built an automated liquid separator customized to the lab’s needs for $500. The lab members dubbed the invention the LEGO MINDSTORMS Fraction Collector. They published instructions for how to build it in a journal so that other researchers can tap the simple, but effective, technology. 

The lab's homemade fraction collector.

The Quave lab first separated out a group of molecules from the plant extract, cycloartane triterpenoids, and showed for the first time that this group actively blocks the virulence of MRSA. The researchers then dove deeper, separating out the single, most active molecule from this group, now known as Castaneroxy A. 

“Our homemade piece of equipment really helped accelerate the pace of our discovery,” Quave says. “We were able to isolate this molecule and derive pure crystals of it, even though it only makes up a mere .0019 percent of the chestnut leaves.” 

Tests on mouse skin infected with MRSA, conducted in the lab of co-author Alexander Horswill at the University of Colorado, confirmed the molecule’s efficacy at shutting down MRSA’s virulence, enabling the skin to heal more rapidly. 

Co-author John Bacsa, director of Emory Department of Chemistry’s X-ray Crystallography Center, characterized the crystal shape of Castaneroxy A. Understanding the three-dimensional configuration of the crystal is important for future studies to refine and optimize the molecule as a potential therapeutic.

“We’re laying the groundwork for new strategies to fight bacterial infections at the clinical level,” Quave says. “Instead of being overly concerned about treating the pathogen, we’re focusing on ways to better treat the patient. Our goal is not to kill the microbes but to find ways to weaken them so that the immune system or antibiotics are better able to clear out an infection.” 

Emory co-authors of the paper also include graduate students Caitlin Risener and Lewis Marquez; post-doctoral fellow Gina Porras; and former staff scientist James Lyles. Additional authors from the University of Colorado are Young-Saeng Cho and Morgan Brown. 

The work was funded by the National Center for Complementary and Integrative Health, Emory’s Department of Dermatology, the National Institute of Allergy and Infectious Diseases and the National Institute of General Medical Sciences.

Related:

Brazilian peppertree packs power to knock out antibiotic-resistant bacteria

Major review of plants' role in antibacterial activity clears new paths for drug discovery

Chestnut leaves yield extract that disarms deadly bacteria

Tuesday, June 8, 2021

Study shows adaptive brain response to stress, and its absence in people with depression

"Learning more about how acute stress and chronic stress affect the brain may help in the development of treatment targets for depression," says Jessica Cooper, first author of the study and a post-doctoral fellow in Emory's Department of Psychology.

By Carol Clark

A new study identifies a novel biomarker indicating resilience to chronic stress. This biomarker is largely absent in people suffering from major depressive disorder, and this absence is further associated with pessimism in daily life, the study finds. 

Nature Communications published the research by scientists at Emory University. 

The researchers used brain imaging to identify differences in the neurotransmitter glutamate within the medial prefrontal cortex before and after study participants underwent stressful tasks. They then followed the participants for four weeks, using a survey protocol to regularly assess how participants rated their expected and experienced outcomes for daily activities. 

“To our knowledge, this is the first work to show that glutamate in the human medial prefrontal cortex shows an adaptive habituation to a new stressful experience if someone has recently experienced a lot of stress,” says Michael Treadway, senior author of the study and professor in Emory’s Department of Psychology and Department of Psychiatry and Behavioral Science. “Importantly, this habituation is significantly altered in patients with depression. We believe this may be one of the first biological signals of its kind to be identified in relation to stress and people who are clinically depressed.” 

“Learning more about how acute stress and chronic stress affect the brain may help in the identification of treatment targets for depression,” adds Jessica Cooper, first author of the study and a post-doctoral fellow in Treadway’s Translational Research in Affective Disorders Laboratory

The lab focuses on understanding the molecular and circuit-level mechanisms of psychiatric symptoms related to mood disorders, anxiety and decision-making. 

It’s long been known that stress is a major risk factor for depression, one of the most common and debilitating of mental illnesses. “In many ways, depression is a stress-linked disorder,” Treadway says. “It’s estimated that 80 percent of first-time depressive episodes are preceded by significant, chronic life stress.” 

Around 16 to 20 percent of the U.S. population will meet the criteria for a major depressive disorder during their lifetimes. Experts are predicting rates of depression to climb even further in the wake of the ongoing COVID-19 pandemic. During the pandemic, about four in 10 adults in the United States have reported symptoms of anxiety or depressive disorder, up from one in 10 who reported them in 2019, according to the Kaiser Family Foundation. 

“The pandemic has created more isolation for many people, while also increasing the amount of severe stressors and existential threats they experience,” Treadway says. “That combination puts a lot of people at high risk for becoming depressed.” 

Although the link between stress and depression is clearly established, the mechanisms underlying this relationship are not. Experiments with rodents have shown an association between the response of glutamate — the major excitatory neurotransmitter in the mammalian brain — and stress. The role of glutamate in humans with depression, however, has been less clear. 

The 88 participants in the current study included people without a mental health disorder and unmedicated patients diagnosed with a major depressive disorder. Participants were surveyed about perceived recent stress in their lives before they underwent experiments using a brain scanning technique known as magnetic resonance spectroscopy. 

While in the scanner, participants were required to alternate between performing two tasks that served as acute stressors: Putting their hand up to the wrist in ice water and counting down from the number 2,043 by steps of 17 while someone evaluated their accuracy. 

Brain scans before and after the acute stressor measured glutamate in the medial prefrontal cortex, an area of the brain involved with thinking about one’s state and forming expectations. Previous research has also found that this brain area is involved in regulating adaptive responses to stress. 

Participants submitted saliva samples while in the scanner, allowing the researchers to confirm that the tasks elicited a stress response by measuring the amount of the stress hormone cortisol in the sample. 

In healthy individuals, the brain scans revealed that glutamate change in response to stress in the medial prefrontal cortex was predicted by individual levels of recent perceived stress. Healthy participants with lower levels of stress showed increased glutamate in response to acute stress, while healthy participants with higher levels of stress showed a reduced glutamate response to acute stress. This adaptive response was comparatively absent in the patients diagnosed with depression. 

“The decrease in the glutamate response over time appears to be a signal, or a marker, of a healthy adaptation to stress,” Treadway says. “And if the levels remain high that appears to be a signal for maladaptive responses to stress.” 

The initial result was strong for the adaptation in healthy participants, but was in a modest sample size, so the researchers decided to see if they could replicate it. “Not only did we get a replication, it was an unusually strong replication,” Treadway says. 

The experiment also included a group of healthy controls who underwent scanning before and after performing tasks. Rather than stressful tasks, however, the controls were asked to place a hand into warm water or to simply count out loud consecutively. Their glutamate levels were not associated with perceived stress and they did not show a salivary cortisol response. 

To expand their findings, the researchers followed participants for four weeks after scanning. Every other day, the participants reported on their expected and experienced outcomes for activities in their daily lives. The results showed that glutamate changes that were higher than expected based on an individual’s level of perceived stress predicted an increased pessimistic outlook — a hallmark for depression. 

“We were able to show how a neural response to stress is meaningfully related to what people experience in their daily lives,” Cooper says. “We now have a large, rich data set that gives us a tangible lead to build upon as we further investigate how stress contributes to depression.” 

Emory co-authors of the study include former and current graduate students from the Treadway lab Victoria Lawlor, Shabnam Hossein and Andrew Teer; as well as current and former research assistants Makiah Nuutinen, Brittany DeVries, Daniel Cole, Chelsea Leonard and Emma Hahn. Additional authors include researchers from UCLA, the University of Arkansas, Princeton and McLean Hospital/Harvard Medical School. 

The work was supported by the National Institutes of Mental Health.

Related:

How the brain decides to make an effort

How chronic inflammation may drive down dopamine and motivation

Study reveals how the brain decides to make an effort


Wednesday, June 2, 2021

Flow of slushy sea ice predicts glacier calving

A view of Illusiat Glacier shows the ice melange (in the foreground) and the sheered off edge of the glacier where a massive ice sheet just broke away. (Jason Amundson)

Ice mélange, the mass of floating sea ice that buttresses many tidewater glaciers, plays a major role in the timing of calving icebergs, finds a new study published in Nature Geoscience

Scientists measured how just a tiny shift in the flow of a mélange, from smooth to slightly more chaotic, can predict up to one hour in advance that a massive hunk of ice will break off from a glacier, then crash into the ocean to form a new iceberg. 

“As a gateway to the ocean, ice mélange is critical to predictions of sea-level rise,” says Justin Burton, associate professor of physics at Emory University and co-author of the paper. “We’ve provided what may be the best, most high-resolution data ever on the dynamics of a mélange leading up to a major calving event. That helps us understand the forces determining how much ice melts into the ocean, and how fast it happens.” 

Ryan Cassotto, a glaciologist from the University of Colorado, Boulder, is lead author of the paper. Co-authors include Jason Amundson from the University of Alaska Southeast, Juneau; and Mark Fahnestock and Martin Truffer, both from the University of Alaska Fairbanks. 

The study’s data was drawn from Ilulissat, a World Heritage Site and the most productive tidewater glacier in Greenland, also known as Jakobshavn Glacier. Kilometer-sized icebergs that calve from Ilulissat often capsize, leading to glacial earthquakes and small tsunamis. 


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Monday, May 24, 2021

Even children think money can be 'dirty' money, study finds

Experiments led by Emory psychologist Arber Tasimi found that children prefer non-stolen money offered by a "bad" person over stolen money offered by an "okay" person.

 By Carol Clark

When people deposit a $100 bill into their bank accounts, they don’t imagine that when they later withdraw $100 they will get the same bill. After all, the only thing that matters about money is its amount. A dollar is just like any other dollar — unless it comes with a tainted past. 
 
“People tend to imbue objects with essences,” says Arber Tasimi, assistant professor of psychology at Emory University. “We can be put off by objects that we know have a ‘bad’ essence because of an immoral history, like a sweater worn by Hitler. And money doesn’t appear to be an exception.” 

Tasimi’s latest work finds that children as young as five show an aversion to accepting “dirty” money. The journal Cognitive Science published the research, which Tasimi conducted with Susan Gelman, a psychologist at the University of Michigan. 

“This sensitivity to morality, even in the context of money, seems to emerge early,” Tasimi says. “The fact that children are making these distinctions adds to the evidence showing just how much we care about where things come from, particularly when they come from bad sources.” 

Tasimi heads the Morality and Development Lab at Emory. He’s particularly interested in moral conflict — how we wrestle with our desire for personal benefits versus our interest in the welfare of others. 

In previous research, Tasimi found that even babies prefer to take a single graham cracker offered to them by a “nice” puppet rather than two graham crackers offered by a “mean” puppet. But when the mean puppet offers them eight crackers, most babies “sell out.” 

For the current paper, Tasimi wanted to explore how a sense of morality tied to money develops in children. A series of experiments included participants in two age groups: 5-to-6-year-olds and 8-to-9-year-olds. The children were presented with various hypothetical scenarios: A person offering them a dollar. A person offering them a stolen dollar that they had found. A “bad” person who stole a dollar but was offering them a dollar they did not steal. And a “bad” person offering them a dollar that they had stolen. 

The results showed that the children significantly rejected “dirty” money. They much preferred non-stolen money offered by a “bad” person than stolen money offered by an “okay” person. 

“What we find over and over is that the morality of the money plays a critical role in whether people decide to take it,” Tasimi says. “Why would we imbue money with ‘badness’? I think that’s the million-dollar question.” 

In ongoing work, Tasimi is delving deeper into possible answers to the mystery. Does the source of the money matter because it could be tainted? Is it due to an aversion to profiting at the expense of others? Or is it because accepting the tainted money somehow endorses the immoral activity behind it? 

“I’m also intrigued by individual differences,” Tasimi adds. “Some people do treat a dollar like any other dollar, while others don’t. Why are some people bothered by ‘dirty’ money and others are not?”

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Wednesday, April 28, 2021

Human antibiotic use threatens endangered wild chimpanzees

The number of chimpanzees in Gombe National Park, the site of Jane Goodall's groundbreaking field studies, are down to about 95. "By misusing antibiotics, people can actually harm not only themselves, but also the species they share an environment with," says Emory disease ecologist Thomas Gillespie.

By Carol Clark

It’s well established that infectious disease is the greatest threat to the endangered chimpanzees made famous by the field studies of Jane Goodall at Gombe National Park in Tanzania. Now, new research led by scientists at Emory University shows that nearly half of the fecal samples from wild chimpanzees contain bacteria that is resistant to a major class of antibiotics commonly used by people in the vicinity of the park. 

The journal Pathogens published the findings

“Our results suggest that antibiotic-resistant bacteria is actually spreading from people to non-human primates by making its way into the local watershed,” says Thomas Gillespie, senior author of the study and associate professor in Emory’s Department of Environmental Sciences and Rollins School of Public Health. “People are bathing and washing in the streams, contaminating the water with drug-resistant bacteria where wild chimpanzees and baboons drink.” 

The researchers tested for genes conferring resistance to sulfonamides — drugs often used by people in the region to treat diarrheal diseases — in fecal samples from humans, domestic animals, chimpanzees and baboons in and around Gombe National Park. They also tested stream water used by these groups. 

Sulfonamide resistance appeared in 74 percent of the human samples overall, 48 percent of chimpanzee samples, 34 percent of baboon samples, and 17 percent of the domestic animal samples. Sulfonamide also showed up in 19 percent of the samples taken from streams shared by people, domestic animals and wildlife. 

The researchers also tested all the groups in the study for genes conferring resistance to tetracycline — another class of antibiotics that is used much less frequently by people in the vicinity, likely due to its greater expense and the fact that it is less available in the area. As expected, very few of the fecal samples from any of the groups, and none of the water samples from the streams, showed evidence of tetracycline resistance. 

First author of the study is Michele Parsons, who did the work as an Emory doctoral student in Environmental Sciences. Parsons has since graduated and works at the Centers for Disease Control and Prevention (CDC). Co-authors include researchers from the Jane Goodall Institute, the CDC, the University of Minnesota and Franklin and Marshall College. 

Gillespie is a disease ecologist who helped pioneer the “One Health” approach to protect humans, ecosystems and biodiversity. His projects in Africa, including the collaboration with the Jane Goodall Institute in Tanzania, are focused on helping farmers subsisting amid fragmented forests co-exist with primates and other wildlife in ways that minimize the risk of pathogen exchange between species, known as “spillover.” The virus that causes AIDS, for example, spilled over from chimpanzees to people. 

“It’s important to consider both sides of the story — human health and well-being, as well as conservation of chimpanzees and other species,” Gillespie says. 

Human encroachment has taken a toll on the great apes, due to fragmented habitat and the exchange of pathogens. Today, the number of chimpanzees in Gombe National Park are down to about 95. 

Diarrheal diseases are common in the area and people often turn to cheap sulfonamide antibiotics that are available without a prescription at small stores that act as informal pharmacies, selling drugs, soap and other necessities. Wild chimpanzees also suffer from wasting diseases that can be related to bacterial and other enteric pathogens that affect their ability to maintain calorie intake and absorb nutrients. 

“The majority of people in our sampling harbored bacteria resistant to the sulfonamide medication they are taking,” Gillespie says. “In those cases, they’re spending their money on a drug that is not helping them get better. Overuse of such drugs creates the potential for more lethal, antibiotic-resistant ‘super bugs’ to emerge.” 

The research findings will now support the development of interventions. 

More guidance is needed locally regarding the proper use of antibiotics, Gillespie says. He adds that it is also important to improve hygiene for wash-related activities in area streams, as well as to improve disposal of human waste materials. 

“By misusing antibiotics, people can actually harm not only themselves, but also the species they share an environment with,” Gillespie says. “After drug-resistant bacteria jump into chimpanzees, it can further evolve with the chimpanzees and then spill back into humans. We need to be thinking about infectious diseases within evolutionary and ecological frameworks, something that’s not often done in medicine.” 

The study was funded by the Morris Animal Foundation, the Emory Global Health Institute, the Arcus Foundation, the Leo S. Guthman Foundation and the National Institutes of Health.

Related:

Zoo gorillas contract COVID, raising alarms for great apes in the wild

Valuing 'natural capital' vital to avoid next pandemic, experts warn

Disease poses risk to chimpanzee conservation, Gombe study finds

Wednesday, April 21, 2021

Georgia Aquarium otters join list of animals testing positive for SARS-CoV-2

Otters are Mustelids, a diverse group of carnivorous mammals that includes mink and ferret — two other species that have also become infected with SARS-CoV-2. (Getty Images)

By Carol Clark

The recent positive SARS-CoV-2 tests of Asian small-clawed otters at the Georgia Aquarium add to the mystery of why some animals may be more susceptible than others to the virus that causes COVID-19. 

“In one sense, it’s not surprising to see otters infected, because we’ve already seen infections in mink and ferrets, which are closely related species,” says Thomas Gillespie, associate professor in Emory University’s Department of Environmental Sciences and Rollins School of Public Health. 

Otters, mink and ferrets are all Mustelids, a diverse group of carnivorous mammals, notes Gillespie, a disease ecologist who studies how pathogens jump between wildlife, domestic animals and people.

Most of the research into what animal species may be susceptible to SARS-CoV-2 is based on the genetics of protein binding sites that the virus uses to gain a foothold in a host. People, great apes and some monkeys have the highest susceptibility, according to this research, Gillespie says. 

In January, some members of the gorilla troop at the San Diego Zoo tested positive for SARS-CoV-2, after they exhibited COVID-19 symptoms. 

“What’s surprising,” Gillespie says, “is that Mustelids are at the opposite end of the spectrum in terms of a binding propensity with SARS-CoV-2. In one of the more robust studies to date, they fell into the lower range of binding scores among 400 species of vertebrates. And yet, they keep popping up with infections. That’s where the mystery lies.” 

The Georgia Aquarium announced in an April 18 news release that the otters were tested after showing symptoms such as sneezing, runny noses, lethargy and coughing. The animals were removed from their exhibit for behind-the-scenes care and are expected to make a full recovery, the release stated. 

The virus that causes COVID-19 is zoonotic, meaning that it originated in animals — most likely horseshoe bats — and may have passed through another species before making its way to humans. 

“It’s critical right now for the world to focus on preventing human-to-human transmission of the virus,” Gillespie says. “But it’s also important to consider the longer-term, bigger picture of how pathogens can spill over from animals to people and then back to animals again.” 

Gillespie helped pioneer the One Health approach to protecting humans, ecosystems and biodiversity. The primary risks for future spillover of zoonotic diseases are deforestation of tropical environments and large-scale industrial farming of animals, he says. 

In late 2020, COVID-19 outbreaks were seen in mink around the world, including the United States, at farms that mass-produce the animals for the fur trade. The mink are kept in densely packed conditions that are ideal for spreading pathogens, Gillespie says. 

Denmark culled 17 million mink after the virus spread from the human caretakers to the animals, then mutated and spread back to some of the human caretakers. 

“The good news is that there are relatively few documented cases of animal transmission to humans, and these appear to be restricted to the most ideal conditions for transmission, such as the crowded conditions of industrial mink farming,” Gillespie says. 

Ferrets are a common laboratory model for the study of respiratory diseases, due to their unique respiratory biology. Experimental studies have shown that they can easily be infected with SARS-CoV-2. 

The black-footed ferret is among the most endangered mammals in North America. That prompted researchers at the U.S. National Wildlife Health Center last December to start testing a veterinary vaccine for COVID-19 on a captive population of the animals at the National Black-footed Ferret Conservation Center in Colorado. 

Almost all of the species that have tested positive for SARS-CoV-2, including cats, dogs, tigers, gorillas and a few other mammals, live in close proximity to people — either as pets, in zoos or in laboratories. One exception is a wild mink, found near a mink farm in Utah, that tested positive for SARS-CoV-2, according to the U.S. Department of Agriculture. 

“Testing of wildlife is rare,” Gillespie says. “And most testing of captive animals is done only if they show symptoms, suggesting there may be many more asymptomatic cases. There are a lot of important questions into how SARS-CoV-2 may affect animals that we have not yet started exploring.” 

The questions are important to protect both the health of animals and people, he adds. 

“Widespread infection within a population of a novel virus is the kind of event that could potentially push endangered and critically endangered species over the edge,” Gillespie says. “And any time a virus enters a new species with different selective pressures, that provides more opportunities for new mutants of the virus to evolve and potentially spill over into humans.”

Related:

San Diego Zoo gorillas contract COVID, raising alarms for great apes in the wild

Valuing 'natural capital' vital to avoid next pandemic

Bat ecology in the era of pandemics

Wednesday, April 14, 2021

Physicists develop theoretical model for neural activity of mouse brain

"One of the wonderful things about our model is that it's simple," says Mia Morrell, who did the research as an Emory senior majoring in physics. Morrell graduated last year and is now in New Mexico, above, where she is completing a post-baccalaureate physics program at Los Alamos National Laboratory.

By Carol Clark

The dynamics of the neural activity of a mouse brain behave in a peculiar, unexpected way that can be theoretically modeled without any fine tuning, suggests a new paper by physicists at Emory University. Physical Review Letters published the research, which adds to the evidence that theoretical physics frameworks may aid in the understanding of large-scale brain activity. 

“Our theoretical model agrees with previous experimental work on the brains of mice to a few percent accuracy — a degree which is highly unusual for living systems,” says Ilya Nemenman, Emory professor of physics and biology and senior author of the paper. 

The first author is Mia Morrell, who did the research for her honors thesis as an Emory senior majoring in physics. She graduated from Emory last year and is now in a post-baccalaureate physics program at Los Alamos National Laboratory in New Mexico. 

“One of the wonderful things about our model is that it’s simple,” says Morrell, who will start a Ph.D. program in physics at New York University in the fall. “A brain is really complex. So to distill neural activity to a simple model and find that the model can make predictions that so closely match experimental data is exciting.” 

The new model may have applications for studying and predicting a range of dynamical systems that have many components and have varying inputs over time, from the neural activity of a brain to the trading activity of a stock market. 

Co-author of the paper is Audrey Sederberg, a former post-doctoral fellow in Nemenman’s group, who is now on the faculty at the University of Minnesota. 

The work is based on a physics concept known as critical phenomena, used to explain phase transitions in physical systems, such as water changing from liquid to a gas. 

In liquid form, water molecules are strongly correlated to one another. In a solid, they are locked into a predictable pattern of identical crystals. In a gas phase, however, every molecule is moving about on its own. 

“At what is known as a critical point for a liquid, you cannot distinguish whether the material is liquid or vapor,” Nemenman explains. “The material is neither perfectly ordered nor disordered. It’s neither totally predictable nor totally unpredictable. A system at this ‘just right’ Goldilocks spot is said to be ‘critical.’” 

Very high temperature and pressure generate this critical point for water. And the structure of critical points is the same in many seemingly unrelated systems. For example, water transitioning into a gas and a magnet losing its magnetism as it is heated up are described by the same critical point, so the properties of these two transitions are similar. 

In order to actually observe a material at a critical point to study its structure, physicists must tightly control experiments, adjusting the parameters to within an extraordinarily precise range, a process known as fine-tuning. 

In recent decades, some scientists began thinking about the human brain as a critical system. Experiments suggest that brain activity lies in a Goldilocks spot — right at a critical transition point between perfect order and disorder. 

“The neurons of the brain don’t function just as one big unit, like an army marching together, but they are also not behaving like a crowd of people running in all different directions,” Nemenman says. “The hypothesis is that, as you increase the effective distance between neurons, the correlations between their activity are going to fall, but they will not fall to zero. The entire brain is coupled, acting like a big, interdependent machine, even while individual neurons vary in their activity.” 

Researchers began searching for actual signals of critical phenomena within brains. They explored a key question: What fine tunes the brain to reach criticality? 

In 2019, a team at Princeton University recorded neurons in the brain of a mouse as it was running in a virtual maze. They applied theoretical physics tools developed for non-living systems to the neural activity data from the mouse brain. Their results suggested that the neural activity exhibits critical correlations, allowing predictions about how different parts of the brain will correlate with one another over time and over effective distances within the brain. 

For the current paper, the Emory researchers wanted to test whether fine-tuning of particular parameters were necessary for the observation of criticality in the mouse brain experiments, or whether the critical correlations in the brain could be achieved simply through the process of it receiving external stimuli. The idea came from previous work that Nemenman’s group collaborated on, explaining how biological systems can exhibit Zipf’s law — a unique pattern of activity found in disparate systems. 

“We previously created a model that showed Zipf’s law in a biological system, and that model did not require fine tuning,” Nemenman says. “Zipf’s law is a particular form of criticality. For this paper, we wanted to make that model a bit more complicated, to see if could predict the specific critical correlations observed in the mouse experiments.” 

The model’s key ingredient is a set of a few hidden variables that modulate how likely individual neurons are to be active. 

Morrell wrote the computer code to run simulations and test the model on her home desktop computer. “The biggest challenge was to write the code in a way that would allow it to run fast even when simulating a large system with limited computer memory without a huge server,” she says. 

The model was able to closely reproduce the experimental results in the simulations. The model does not require the careful tuning of parameters, generating activity that is apparently critical by any measure over a wide range of parameter choices. 

“Our findings suggest that, if you do not view a brain as existing on its own, but you view it as a system receiving stimuli from the external world, then you can have critical behavior with no need for fine tuning,” Nemenman says. “It raises the question of whether something similar could apply to non-living physical systems. It makes us re-think the very notion of criticality, which is a fundamental concept in physics.” 

The computer code for the model is now available online, so that anyone with a laptop computer can access it and run the code to simulate a dynamic system with varying inputs over time. 

“The model we developed may apply beyond neuroscience, to any system in which widespread coupling to hidden variables is extant,” Nemenman says. “Data from many biological or social systems are likely to appear critical via the same mechanism, without fine-tuning.” 

The current paper was partially supported by grants from the National Institutes of Health and the National Science Foundation.

Related:

Physicists eye neural fly data, find formula for Zipf's law

Biophysicists take small step in quest for 'robot scientist'

Tuesday, April 6, 2021

Chemists develop tools that may help improve cancer diagnostics, therapeutics

A process known as methylation helps regulate on-and-off switches to keep a host of systems in the body functioning normally. "But the process can get hijacked, creating modifications that may lead to diseases," explains Ogonna Nwajiobi (above), an Emory Ph.D. student in chemistry and first author of the paper.

By Carol Clark

Chemists developed a method to detect changes in proteins that may signal the early stages of cancer, Alzheimer’s, diabetes and other major diseases. Angewandte Chemie published the work, led by chemists at Emory University and Auburn University. The results offer a novel strategy for studying links between unique protein modifications and various pathologies. 

“The knowledge we gain using our new, chemical method holds the potential to improve the ability to detect diseases such as lung cancer earlier, when treatment may be more effective,” says Monika Raj, senior author of the paper and Emory associate professor of chemistry. “A detailed understanding of protein modifications may also help guide personalized, targeted treatment for patients to improve a drug’s efficacy against cancer.” 

The researchers provided a proof of concept for using their method to detect single protein modifications, or monomethylation. Their lab experiments were conducted on the protein lysine expressed from E.coli and other non-human organisms. 

Lysine is one of the nine essential amino acids that is critical to life. After lysine is synthesized in the human body, changes to the protein, known as methylation, can occur. Methylation is a biochemical process that transfers one carbon atom and three hydrogen atoms from one substance to another. Such modifications can occur in single (monomethylation), double (dimethylation) or triple (trimethylation) forms. Demethylation reverses these modifications. 

The small tweaks of methylation and demethylation regulate biological on-off switches for a host of systems in the body, such as metabolism and DNA production. 

“In a normal state, the methylation process creates modifications that are needed to keep your body functioning and healthy,” says Ogonna Nwajiobi, an Emory Ph.D. student in chemistry and first author of the paper. “But the process can get hijacked, creating modifications that may lead to diseases.”

Modifications to lysine, in particular, he adds, have been linked to the development of many cancers and other diseases in humans. 

Sriram Mahesh, from Auburn University is co-first author of the paper. Xavier Streety, also from Auburn, is a co-author. 

The Raj lab, which specializes in developing organic chemistry tools to understand and solve problems in biology, wanted to devise a method to detect monomethylation marks to lysine that have been expressed by an organism. Monomethylation is especially challenging to detect since it leaves negligible changes in the bulk, charge or other characteristics of a lysine modification.

The researchers devised chemical probes, electron-rich diazonium ions, that couple only with monomethlyation sites at certain biocompatible conditions that they can control, including a particular pH level and electron density. They used mass spectroscopy and nuclear magnetic resonance techniques to show that they had selectively hit the correct targets, and to confirm the coupling of atoms at the sites. 

The method is unique because it directly targets the monomethylation sites. Another unique feature of the method is that it is reversible under acidic conditions, allowing the researchers to uncouple the atoms and regenerate the original state of a monomethylation site. 

The Raj lab now plans to collaborate with researchers at Emory’s Winship Cancer Institute to test the new method on tissue samples taken from lung cancer patients. The goal is to home in on differences in lysine monomethylation sites of people with and without lung cancer. 

“It’s like a fishing expedition,” Nwajiobi explains. “The first step is to use our method to find the lysine monomethylation sites in tissue samples, which is difficult to do because of their low abundance. Once we’ve found the sites, our method then allows us to reverse the coupling with our chemical probe, so the functions of the sites can be studied in their intact, original forms.” 

Practical methods for early detection of many diseases, like lung cancer, are needed to help improve patient outcomes. “If we can develop more ways to identify lung cancer earlier, that may open the door for treatments that greatly improve the survival rate,” Raj says. 

The researchers hope to study lysine monomethylation differences between samples taken from patients at different stages of lung cancer, between patients with or without a family history of the disease, and between those who have smoked and those who have not. Knowledge gained from such analyses could set the stage for more personalized, targeted treatments, Raj says. 

Her lab is also developing chemical tools to selectively detect lysine dimethylation and trimethylation sites, in order to help more fully characterize the role of lysine methylation in disease. 

“We hope that other researchers will also apply our methods, and the chemical tools we are developing, to better understand a range of cancers and many other diseases associated with lysine methylation,” Raj says. 

The work was funded by the National Science Foundation.

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