The Peeps experiments: A seasonal celebration of science

Why experiment on Peeps? "Because they're there!" says Emory chemist Douglas Mulford. Photo by Carol Clark.

It’s that time of year again when Peepus Marshmalleous, commonly known as Peeps, pop up everywhere — even in an Emory University chemistry lab.

Emory's groundbreaking Peeps research began in 1999 when researchers Gary Falcon and James Zimming investigated the effects of smoking and alcohol on Peeps health and performed the medical miracle of separating quintuplet Peep siblings, conjoined at birth. You can read more here: peepresearch

Douglas Mulford, senior lecturer and director of undergraduate studies for the Department of Chemistry, continues the tradition by treating students every spring to a Peeps show. “Basically, it’s 45-minutes of every chemical thing that you can do to a Peeps,” Mulford explains. “It’s amazing what they can survive.” 

Watch a brief video summarizing the show, below. And check out Emory’s new Instagram account, Science Seen, for more quick, behind-the-scenes looks at science at Emory.

Frankenstein at 200 sparks wonder and debate

Emory's Stuart A. Rose Manuscript, Archives and Rare Book Library holds an 1881 original edition of "Frankenstein" and an 1831 edition, above, with a depiction of the "creature" and a prologue by Mary Shelley.

It’s the 200th anniversary year of “Frankenstein, Or the Modern Prometheus,” an enduring novel at the nexus of major questions of our time. Emory faculty explore many of them in a newly published anthology, “Frankenstein: How a Monster Became an Icon, the Science and Enduring Allure of Mary Shelley’s Creation.”

“When you see a contemporary film about androids, like ‘Blade Runner 2049,’ you’re seeing the ‘Frankenstein’ story in a 21st-century guise,” says Sidney Perkowitz, Emory emeritus physicist and co-editor of the new anthology. “The androids are sleek and modern instead of the shambling, stitched-together creature in ‘Frankenstein,’ but they have the same questions swirling around them. Even as we’re on the verge of artificially generating life, we’re no closer to knowing whether we should.”

You can read more here.

Related:
Chemists boldly go in search of 'little green molecules'
Prometheus: Seeding wonder and science

Frankenstein and robots rise up for Atlanta Science Festival

Hair-raising, spine-tingling fun: A young visitor to the Emory campus during last year's Atlanta Science Festival experiences the thrill of static electricity.

By Carol Clark

From the lumbering, 200-year-old Frankenstein to sleek, modern-day robots, this year’s Atlanta Science Festival — set for March 9 to 24 — highlights creations that spark wonder and fun, giving glimpses of the past and the future.

The five-year-old festival expanded to more than two weeks, encompassing 120 events sponsored by 90 different partners at 70 venues across metro Atlanta, including many on the Emory campus. The festival culminates with a day-long “Exploration Expo” on Saturday, March 24, set in Piedmont Park.

“Rise Up, Robots!” kicks off the festival on the evening of Friday, March 9 at the Ferst Center, when three robots and their inventors will take the stage.

“We thought about how we could possibly top last year’s featured speaker, astronaut Mark Kelly — someone so inspirational to children and adults all over the planet,” says Meisa Salaita, co-director of the Atlanta Science Festival. “We finally realized that no human could match him, and we would have to resort to artificial intelligence.”

Heather Knight, professor of robotics at Oregon State University, will demonstrate the interactive quips of “Data,” the world’s first robotic comedian. Georgia Tech’s Gil Weinberg will jam with “Shimon,” a marimba playing robotic musician. And Stewart Coulter, from DEKA Research and Development, will show how a bionic arm named LUKE (Life Under Kinetic Evolution) changed an amputee’s life.

Tickets are required for the event, which starts at 7 pm. Door open early with an Interactive Robotic Petting Zoo, starting at 6 pm.

Frankenstein rises up on the Emory campus on Thursday, March 22. Three Atlanta playwrights will reanimate Mary Shelley’s creation, which turns 200 this year, in the context of scientific research ongoing at Emory. Following the short plays join ethicists, scientists and the playwrights to discuss the work over refreshments. The event, titled “Frankenstein Goes Back to the Lab,” begins at 5:30 pm in Emory’s Science Commons.

On Friday, March 23, from 3:30 to 7 pm, Emory will host “Chemistry Carnival,” where visitors can join scientists in carnival games like Peptide Jenga and Bacterial Telepathy, in the Atwood Chemistry Center. On the same day and time, the ever-popular “Physics Live!” will again feature giant soap bubbles and liquid nitrogen ice cream, among other treats in the Math and Science Center.

A new Emory event this year, “Science.Art.Wonder,” will run concurrently with the chemistry and physics events, on the Emory Quadrangle and in nearby buildings, including White Hall and the Atwood Chemistry Center. For the past year, the program has paired local artists and scientists to explore ideas of research through the visual arts. You can stroll through an exhibit of the resulting artwork and meet some of the artists and scientists involved in the project.

Adult fare is featured on Monday, March 19, including “The Science of ‘Motherese,’” an overview of early vocal development in infants at the Marcus Autism Center, and “CDC in the Scene,” which features CDC scientists sorting fact from fiction surrounding movies like “Outbreak,” in the Mathematics and Science Center.

On Tuesday, March 20, “Become an Archeologist” lets you in on secrets revealed by ancient skeletons and artifacts, while “Mock Climate Change Negotiation” turns you into an international policymaker for a day.

During “Unveiling the Internet,” on Wednesday, March 21, Emory computer scientists will give interactive lessons on everything from the workings of YouTube to Snapchat.

“STEM Gems: Giving Girls Role Models in STEM Careers,” on Saturday, March 10, is an interactive discussion where panelists offer advice and guidance specific to girls and young women intrigued by science, technology, engineering and math. “Women and Minorities in STEM: Surprises, Setbacks and Successes,” set for the evening of Thursday, March 22 at the Oxford campus, is a panel discussion with voices from a diverse set of scientific fields who will share their stories and take questions.

Click here for more details of Emory campus events, and events throughout the city featuring members of the Emory community.

Among the dozen Emory booths at “Exploration Expo” will be chemistry students running their non-Newtonian fluid dance pit. The Center for the Study of Human Health will explore the human gut microbiome in a booth called “Your Hundred Trillion Best Friends.” And the “Science.Art.Wonder” team will display art from the program and invite you to help create a mural.

The Atlanta Science Festival was founded by Emory, Georgia Tech and the Metro Atlanta Chamber and is a collaboration among diverse community partners and sponsors.

New method calculates equilibrium constant at the small scale

Mixing computational chemistry and theoretical math proved a winning formula for Emory chemist James Kindt (center), his graduate students (from left) Xiaokun Zhang and Lara Patel, and mathematics graduate students Olivia Beckwith and Robert Schneider. Photo by Stephen Nowland, Emory Photo/Video.

By Carol Clark

Computational chemists and mathematicians have developed a new, fast method to calculate equilibrium constants using small-scale simulations — even when the Law of Mass Action does not apply.

The Journal of Chemical Theory and Computation published the resulting algorithm and software, which the researchers have named PEACH — an acronym for “partition-enabled analysis of cluster histograms” and a nod to the method’s development in Georgia at Emory University.

“Our method will allow computational chemists to make better predictions in simulations for a wide range of complex reactions — from how aerosols form in the atmosphere to how proteins come together to form amyloid filaments implicated in Alzheimer’s disease,” says James Kindt, an Emory professor of computational chemistry, whose lab led the work.

Previously it would require at least a week of computing time to do the calculations needed for such predictions. The PEACH system reduces that time to seconds by using tricks derived from number theory.

“Our tool can use a small set of data and then extrapolate the results to a large-system case to predict the big picture,” Kindt says.

“What made this project so fun and interesting is the cross-cultural aspects of it,” he adds. “Computational chemists and theoretical mathematicians use different languages and don’t often speak to one another. By working together we’ve happened onto something that appears to be on the frontiers of both fields.”

The research team includes Lara Patel and Xiaokun Zhang, who are both PhD students of chemistry in the Kindt lab, and number theorists Olivia Beckwith and Robert Schneider, Emory PhD candidates in the Department of Mathematics and Computer Science. Chris Weeden, as an Emory undergraduate, contributed to early stages of the work.

The equilibrium constant is a basic concept taught in first-year college chemistry. According to the Law of Mass Action, at a given temperature, no matter how much of a product and a reactant are mixed together — as long as they are at equilibrium — a certain ratio of product to reactant will equal the equilibrium constant.

“That equation always holds true at equilibrium for huge numbers of molecules,” Kindt says. “It doesn’t matter if it’s applied to a bucket of water or to a single drop of water — which consists of about a billion trillion molecules.”

At much smaller scales of around dozens of molecules, however, the Law of Mass Action breaks down and does not apply.

The Kindt lab uses computers to simulate the behavior of molecules, in particular how they self-assemble into clusters. Sodium octyl sulfate, or SOS, is one of the compounds the lab uses as an experimental model. SOS is a surfactant that can act as a detergent. It forms little clusters in water that can encapsulate oil and grease. Simulations of how SOS molecules come together can predict the distribution of sizes of clusters formed under different conditions, in order to improve the design of soaps and detergents, and to better understand biological processes such as how bile salts break down globules of fat during the digestive process.

In a key test of their model, the lab needed to make sure that the equilibrium for the assembly reaction of SOS molecules into clusters matched up with experiments.

“If we were to run simulations with huge numbers of molecules, we could count the clusters that were formed of each size, count the molecules that remained free of the clusters, and use this information to calculate the equilibrium constant for forming each size cluster,” Kindt says. “The challenge we faced was that it would take too long for the computers to perform simulations of sufficiently huge numbers of molecules to get this to work, and for the numbers of clustering molecules we could practically handle — around 50 — the Law of Mass Action wouldn’t work.”

Kindt decided to approach the problem by considering all the different ways the molecules in a reaction could group into clusters of different sizes in order to arrive at an average. After doing some reading, he realized that these different ways of molecules grouping were what number theorists call integer partitions.

A partition of a number is a sequence of positive integers that add up to that number. For instance, there are five partitions of the number 4 (4 = 3+1 = 2+2 = 2+1+1 = 1+1+1+1). The partition numbers grow at an incredible rate. The amount of partitions for the number 10 is 42. For the number 100, the partitions explode to more than 190,000,000.

That same explosion of possibilities occurs for the ways that molecules can cluster.

Lara Patel and Xiaokun Zhang worked on a “brute force” method to get a computer to run through every single way to combine 10 molecules of one type with 10 molecules of another type. The problem was it took one computer working a couple of days to do a single analysis. And the computational time needed if just a few more molecules were added to the analysis went up exponentially.

The computational chemists had hit a wall.

Kindt reached out to Ken Ono, a world-renowned number theorist in Emory's Mathematics and Computer Science Department, to see if any of his graduate students would be interested in taking a crack at the problem.

Olivia Beckwith and Robert Schneider jumped at the chance.

“The Kindt lab’s computer simulations show that classical theorems from partition theory actually occur in nature, even for small numbers of molecules,” Schneider says. “It was surprising and felt very cosmic to me to learn that number theory determines real-world events.”

“It was definitely unexpected,” adds Beckwith. “In theoretical math we tend to work in isolation from physical phenomena like the interaction of molecules.”

The chemists and mathematicians began meeting regularly to discuss the problem and to learn one another’s terminology. “I had to pull out my son’s high school chemistry book and spend a weekend reading through it,” Schneider says.

“It happened so organically,” Patel says of the process of blending their two specialties. “Olivia and Robert would write equations on the board and as soon as a formula made sense to me I’d start thinking in my head, ‘How can we code this so that we can apply it?’”

The two mathematicians suggested a strategy that could make the problem much easier to calculate, based on a theorem known as Faà di Bruno’s Formula.

“It was surprising,” Zhang says, “because it was an idea that never would have occurred to me. They helped us get unstuck and to find a way to push our research forward.”

“They helped us find a shortcut so that we didn’t have to generate all the partitions for ways that the molecules could clump together,” Kindt adds. “Their algorithm is a much more elegant and simple way to find the entire average overall.”

Patel and Zhang used this new algorithm to put together a piece of software to analyze data from the computer simulations. The resulting system, PEACH, speeds up calculations that previously took two hours to just one second. After demonstrating how PEACH simplifies simulations of SOS assemblages, the research team is moving on to simulate this process for a range of other molecules.

“We’re interested in describing how molecular structures dictate assembly in any type of scenario, such as the early stages of crystal formation,” Kindt says. “We’re also working on quantifying just where the Law of Mass Action breaks down. We could then refine the PEACH strategy to make it even more efficient.”

Related:
New theories reveal the nature of numbers

New methods reveal the biomechanics of blood clotting

An electron micrograph shows a red blood cell, an activated platelet (in yellow) and a white blood cell. The ability to map the magnitude and orientation of forces on a cell provides a new tool for investigating not just blood clotting but a range of biomechanical processes. (NCI photo)

By Carol Clark

Platelets are cells in the blood whose job is to stop bleeding by sticking together to form clots and plug up a wound. Now, for the first time, scientists have measured and mapped the key molecular forces on platelets that trigger this process.

The extensive results are published in two separate studies, in the Proceedings of the National Academy of Sciences (PNAS) and in Nature Methods. “We show conclusively that, in order to activate clotting, the cell needs a targeted force of a magnitude of just a few piconewtons — or a force about a billion times less than the weight of a staple,” says Khalid Salaita, associate professor in Emory University’s Department of Chemistry and the lead author of the studies. “The real surprise we found is that platelets care about the direction of that force and that it has to be lateral. They’re very picky. But they should be picky because otherwise they might accidentally create a clot. That’s what causes strokes.”

Fibrinogen, the third most abundant protein in blood, acts like glue to stick platelets together as a clot forms. Each platelet has about 70,000 copies of a receptor for fibrinogen on its surface. These receptors can work like grappling hooks to latch onto fibrinogen.

“What was puzzling,” Salaita explains, “is that platelets, despite having all these receptors, do not normally latch onto the abundant fibrinogen. They keep flowing past it until you have an injury and fibrinogen becomes anchored. Then the platelets rapidly bind to fibrinogen allowing platelets to aggregate and for clotting to proceed.”



The Salaita lab is a leader in visualizing and mapping the mechanical forces applied by cells. In order to explore the biomechanics of blood clotting, the lab teamed up with physician and biomedical engineer Wilbur Lam, an expert in hematology at Emory’s School of Medicine. Both Salaita and Lam are also affiliated with Emory’s Winship Cancer Institute and the Wallace H. Coulter Department of Biomedical Engineering at Emory and Georgia Tech.

In initial experiments, for the PNAS paper, the Salaita lab anchored fibrinogen ligands onto a lipid membrane. On this surface, the ligands could slip and slide laterally, but resisted motion perpendicular to the surface — similar to the way a hockey puck slides easily over the surface of an ice rink but is harder to lift off of the plane of ice. The researchers then introduced platelets to this surface and experiments showed that the platelets failed to activate and stick together.

In contrast, when the fibrinogen ligands were anchored to a glass slide and unable to move laterally, the platelets rapidly activated. Using tension-imaging technology it developed, the Salaita lab showed that the platelets applied forces between five and 20 piconewtons to initiate activation.

“Platelets have to walk this tightrope between stopping bleeding quickly and accurately during an injury but avoiding unnecessary clotting. Mistakes could be fatal,” Salaita says. “We think they use this lateral force signal like a safety lock to prevent unnecessary clotting.”

Blood vessels are lined with endothelial cells and an injury exposes the fibrous matrix underneath these cells, Salaita explains. Platelets and fibrinogen in the blood can then stick to the injury site.

Salaita theorizes that when a platelet encounters stuck fibrinogen molecules, the platelet tugs on this fibrinogen as a way to test it. The resulting force generates a potent signal to activate platelets and that allows them to grab the fibrinogen from the blood, driving the process of clumping with other platelets.

The abnormal clotting that leads to strokes, and the uncontrollable bleeding of hemophilia, may be related to malfunctions in this biomechanical mechanism, he adds.

In 2011, the Salaita lab developed a fluorescence-sensor method for mapping cell mechanics. Alexa Mattheyses, a cell biologist at Emory’s School of Medicine and Winship Cancer Institute, teamed with the lab to test whether fluorescence polarization could be applied to map the direction of cell forces and provide further insights into the biomechanics of blood clotting.

The results, published in the Nature Methods paper, showed that they could.

Mattheyses “is a guru of fluorescence polarization,” Salaita says. She built a dedicated microscope that allowed mapping force direction at piconewton resolution. She also worked with Joshua Brockman and Aaron Blanchard, graduate students in the Salaita lab, to develop the new imaging technology.

The technique uses DNA molecules as force probes, which behave like molecular ropes and extend in the direction that a cellular force pulls. A series of microscopy images captures the orientation of the DNA, which can then be used to calculate the orientation of piconewton cell forces.

“We got really good at measuring and mapping magnitude, using fluorescence to see how stretched a polymer was,” Salaita says. “Now we can also see which direction a polymer is pointing, in three dimensions.”

Experiments revealed that as platelets begin sticking together to form a clot they contract toward a line, or central axis, in each cell. They do not, however, pull together toward a shared central axis. “It’s similar to having a group of people in a room that are all facing different directions,” Salaita explains. “When they join hands and everybody pulls inward you still get a cluster but the direction that each person is pulling is randomly oriented.”

The ability to map both the magnitude and orientation of forces on a cell provides a powerful tool for investigating not just blood clotting but a range of biomechanical processes, from immune cell activation and embryo development to the replication and spread of cancer cells.

“We’ve developed a completely new way to see things that were not visible before,” Salaita says. “It’s a basic tool with broad applications to help understand why cells are doing things and maybe predict what they’re going to do next.”

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New catalyst controls activation of a carbon-hydrogen bond

A side view of the new catalyst. The dirhodium, shown in blue, "is the engine that makes the catalyst work," says Emory chemist Huw Davies. "The shape of the scaffold around the dirhodium is what controls which C-H bond the catalyst works on." (Graphic image by Kuangbiao Liao)

By Carol Clark

Chemists have developed another catalyst that can selectively activate a carbon-hydrogen bond, part of an ongoing strategy to revolutionize the field of organic synthesis and open up new chemical space.

The journal Nature is publishing the work by chemists at Emory University, following on their development of a similar catalyst last year. Both of the catalysts are able to selectively functionalize the unreactive carbon-hydrogen (C-H) bonds of an alkane without using a directing group, while also maintaining virtually full control of site selectivity and the three-dimensional shape of the molecules produced.

“Alkanes have a lot of C-H bonds and we showed last year that we can bring in one of our catalysts and pluck out a particular one of these bonds and make it reactive,” says Huw Davies, an Emory professor of organic chemistry whose lab led the research. “Now we are reporting a second catalyst that can do the same thing with another C-H bond. We’re building up the toolbox, and we’ve got more catalysts in the pipeline that will continue to expand the toolbox for this new way of doing chemistry.”

Selective C-H functionalization holds particular promise for the pharmaceutical industry, Davies adds. “It’s such a new strategy for making chemical compounds that it will opens up new chemical space and the possibility of making new classes of drugs that have never been made before.”

Alkanes are the simplest of molecules, consisting only of hydrogen and carbon atoms. They are cheap and plentiful. Until the recent development of the catalysts by the Davies lab, however, alkanes were considered non-functional, or unreactive, except in uncontrollable situations such as when they were burning.

The first author of the Nature paper is Emory chemistry graduate student Kuangbiao Liao.

Davies is the director of the National Science Foundation’s Center for Selective C-H Functionalization (CCHF), which is based at Emory and encompasses 15 major research universities from across the country, as well as industrial partners. The NSF recently awarded the CCHF renewed funding of $20 million over the next five years.

The CCHF is leading a paradigm shift in organic synthesis, which has traditionally focused on modifying reactive, or functional, groups in a molecule. C-H functionalization breaks this rule for how to make compounds: It bypasses the reactive groups and does synthesis at what would normally be considered inert carbon-hydrogen bonds, abundant in organic compounds.

“Twenty years ago, many chemists were calling the idea of selectively functionalizing C-H bonds outrageous and impossible,” Davies says. “Now, with all of the results coming out of the CCHF and other research groups across the world they’re saying, ‘That’s amazing!’ We’re beginning to see some real breakthroughs in this field.”

Many other approaches under development for C-H functionalization use a directing group — a chemical entity that combines to a catalyst and then directs the catalyst to a particular C-H bond. The Davies lab is developing a suite of dirhodium catalysts that bypass the need for a directing group to control the C-H functionalization. The dirhodium catalysts are encased within a three-dimensional scaffold.

“The dirhodium is the engine that makes the chemistry work,” Davies says. “The shape of the scaffold around the dirhodium is what controls which C-H bond the catalyst works on.”

Additional co-authors of the Nature paper include Thomas Pickel, Vyacheslav Boyarskikh and John Basca (from Emory’s Department of Chemistry) and Djamaladdin Musaev (from Emory’s Department of Chemistry and the Cherry L. Emerson Center for Scientific Computation).

Related:
Chemists find 'huge shortcut' for organic synthesis using C-H bonds
NSF awards Emory's Center for Selective C-H Functionalization $20 million

Bacteria in a beetle makes it a leaf-eater

The tortoise beetle, which eats thistle leaves, has evolved a symbiotic relationship with bacteria that allows it to have such a specialized diet. Photo by Hassan Salem.

By Carol Clark

A leaf-eating beetle has evolved a symbiotic relationship with bacteria that allows the insect to break down pectin — part of a plant’s cell wall that is indigestible to most animals.

The journal Cell published the findings on the novel function of the bacterium, which has a surprisingly tiny genome — much smaller than previous reports on the minimum size required for an organism not subsisting within a host cell.

“This insect is a leaf eater largely because of these bacteria,” says Hassan Salem, lead author of the study and a post-doctoral fellow in Emory University’s Department of Biology. “And the bacteria have actually become developmentally integrated into the insect’s body.”

Two organs alongside the foregut of the beetle Cassida rubiginosa house the bacteria and appear to have no other function than to maintain these microbes. “The organs are equivalent to the liver in humans, in the sense that they contain the tools to break down and process food,” Salem says.

The newly characterized bacterium has only 270,000 DNA base pairs in its genome, compared to the millions that are more typical for bacterial strains. That makes its genome closer to that of intracellular bacteria and organelles than to free-living microbes. Mitochondria, for example, the organelles that regulate metabolism within cells, have 100,000 base pairs.

The two symbiotic organs of the tortoise beetle, dyed a fluorescent green, are shown on either side of the insect's foregut. Microscopy image by Hassan Salem.

Salem is a researcher in the lab of Emory biologist Nicole Gerardo, an associate professor who specializes in the evolutionary ecology of insect-microbe interactions. The lab combines genomic and experimental approaches to learn how both beneficial and harmful microbes establish and maintain relationships with their hosts.

A human gut holds about 10,000 species of bacteria. These microbial communities, which can be genetically characterized as microbiomes, are transferred generationally but are also dynamic and respond to environmental changes. The microbiome of an urbanite, for example, has different characteristics from that of a hunter-gatherer.

Unlike humans, insects tend to have specialized feeding ecologies. They offer simple models to study symbiotic relationships between microbes and their hosts.

Salem with Buchner's book

Salem became fascinated by Cassida rubiginosa, more commonly known as the tortoise beetle, while he was a graduate student at the Max Planck Institute for Chemical Ecology in Jena, Germany. He was leafing through a 1953 edition of a book by the late Paul Buchner, a German scientist and one of the pioneers of systematic symbiosis research in insects. Buchner referenced a paper published in 1936 by one of his students, Hans-Jurgen Stammer, on Cassida rubiginosa.

“Stammer wrote that, unlike most leaf-eating beetles that he had studied, this one had sac-like organs that he had never seen before and the organs were filled with micro-organisms,” says Salem, who looked up Stammer’s original paper in a now-obscure journal. “He didn’t have the high-powered microscopes that we have now, or genome sequencing technology, so he wasn’t able to comment on the functionality of the mysterious microbes. At that point, the idea that microbes could do anything beneficial for an animal was mushy science.”

Intrigued by the article, Salem went to a nearby woodland to collect some of the leaf beetles. “To find these beetles, you don’t go looking for them,” he explains. “You go looking for the plants they eat.”

The tortoise beetle feeds on the tough, spiny leaves of the Californian thistle (Asteraceae). This prolific weed grows throughout much of the world and is difficult to control. “It pops up in a lot of areas where sheep are maintained,” Salem says. “In fact, it’s a huge pest to New Zealand sheep farmers. The more thistles covering a farmland, the less food the sheep have to eat and the lower the yield. But the thistle is hard to get rid of because its roots run so deep.”

Salem followed the trail of his curiosity to New Zealand, spending time with an agricultural researcher, Michael Cripps, who breeds the tortoise beetle as a bio-control model for thistles. “You drop 100 beetles on a thistle plant and the insects will just drain the plant metabolically until it dies,” Salem explains.

As an herbivore that specializes in eating leaves, the tortoise beetle must consume large amounts of plant cell walls, made of hard-to-digest materials like pectin. One of nature’s most complex polysaccharides, pectin is a gelatinous substance that gives plant cell walls their shape and rigidity. While it was unclear how the beetle obtained needed nutrients of amino acids and vitamins from such a diet, Salem suspected that symbiotic bacteria played a role.

In this cross-section of the symbiotic organ the bacteria it contains are lit up in fluorescent green dye. Microscopy image by Hassan Salem.

When he joined the Gerado lab at Emory, Salem continued to study the tortoise beetle and its micro-organisms with the help of fellow post-doc Aileen Berasategui, a co-author of the Cell paper.

They used genome sequencing technology to characterize the microorganisms as a new species of bacterium. Despite its tiny genome, the bacterium has the power to degrade pectin.

“Just as an apex predator has claws and strong mandibles to obtain the nutritional value that it needs from its prey, the bacterium has pectin-digesting genes that enable the beetle host to deconstruct a plant cell,” Salem says.

After the bacterium breaks down the pectin, the beetle’s digestive system can then access all of the amino acids and vitamins within the plant’s cells for its nutrients.

Salem christened the new bacterium Candidatus Stammera capleta, after Hans-Jurgen Stammer, the ecologist who first glimpsed it and wondered about it more than 80 years ago.

“The most amazing thing to me is that we made this discovery because I read a really old book,” Salem says. “It speaks to the importance of natural history collections and libraries for old journals. We truly stand on the shoulders of giants, extending the work of those who came before us.”

Additional co-authors of the paper are from the Max Planck Institute for Chemical Ecology, the University of Luxembourg, the Lincoln Research Centre in New Zealand, Johannes Gutenberg University in Germany and the National Institute for Advanced Industrial Science and Technology in Japan.

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Mandatory state policies work best to curb power plant emissions, study finds

“Due to the current void in national leadership on the issue of climate change, efforts at the state and local level are more important than ever,” says Eri Saikawa, an assistant professor of Environmental Sciences. Saikawa is part of an Emory delegation to the U.N. Climate Change Conference talks in Bonn, Germany, which includes two faculty and 12 students.

By Carol Clark

U.S. state policies aimed at mitigating power plant emissions vary widely in effectiveness, finds a new study by researchers at Emory University.

Nature Climate Change published the analysis, which shows that policies with mandatory compliance are associated with the largest reductions in power plant emissions.

“Based on the results of our study, we recommend that states adopt a policy of mandatory greenhouse gas emissions registry and reporting for power plants,” says Eri Saikawa, an assistant professor in Emory’s Department of Environmental Sciences. “We also found a significant impact in states that adopt public benefit funds aimed at energy efficiency and renewable energy programs. These two policies not only are effective in reducing power-plant emission levels but also emissions intensity.” 

Saikawa, an expert in public policy and the science of emissions linked to global warming, co-authored the study with Emory graduate Geoff Martin, whose thesis project focused on the topic. Martin received his master’s degree in environmental sciences in May and now works as an energy coordinator for the town of Hartford, Vermont.

Their findings were released today as the U.N. Climate Change Conference (COP23) opens in Bonn, Germany. Delegates from around the world are gathering to hammer out details for meeting the goals of the 2015 Paris Agreement.

The United States was among the 195 countries that committed to this framework to reduce greenhouse gas emissions — although the Trump administration has said it plans to withdraw from this historic accord.

“Due to the current void in national leadership on the issue of climate change, efforts at the state and local level are more important than ever,” Saikawa says. “U.S. cities and states need to step up and do what they can.”

Emory is one of 50 universities from around the country to hold official U.N. observer status for COP23. Saikawa and Sheila Tefft, senior lecturer from the Department of English, will be on the ground in Bonn — leading a delegation of 11 Emory undergraduates and one graduate student as part of their co-taught class, “Climate Change and Society.”

The students will report news live from the event on Twitter under the hashtag #EmoryCOP23. They will also post longer reports, podcasts and videos on a web site they created for the event, Climate Talks Emory University.

Global atmospheric CO2 levels increased at record speed last year, to reach a level not seen for more than three million years, the U.N. warned in a report released last week. The U.S. government’s National Climate Assessment, also released last week, affirmed that climate change is driven almost entirely by human action and detailed how the country is already experiencing more extreme heat and rainfall events, more large wildfires and more flooding due to the warming climate.

About 30 percent of U.S. greenhouse gas emissions come from the electric power sector. For the Nature Climate Change paper, the researchers started out to review the potential impact of President Obama’s Clean Power Plan — which established the first national carbon pollution standards for power plants. When President Trump took office, and announced plans to repeal the Clean Power Plan, the researchers shifted focus.

They analyzed 17 policies adopted by various states relating to climate and energy. States that adopted a mandatory policy for power plants to register and report greenhouse gas emissions, along with three to four other policies, showed the largest reductions, at an average of 2.6 million metric tons of carbon dioxide (CO2) emissions per year.

The second most significant policy involved public benefit funds allotted for energy efficiency and renewable energy programs. That policy was associated with a reduction of about 1.5 million tons of CO2 emissions from power plants, when adopted with three to four other policies.

It’s unclear whether one of these single policies was the actual driver of the reduction in emissions, or an indicator that a state takes climate change mitigation seriously and is attacking the issue on many fronts, Saikawa says.

For instance, three states — New York, Connecticut and Oregon — have each adopted both of the top two most effective policies, along with at least eight other policies.

In 2007, China surpassed the United States as the largest emitter of greenhouse gases globally. “But the per capita emissions in the United States are more than double that of China,” Saikawa notes.

The Obama administration played a key role in securing the Paris Agreement, to keep global warming to no more than 2 degrees Celsius since the start of the Industrial Revolution.

“It will be interesting to hear the take of officials from the Trump administration this year,” Saikawa says. “U.S. coalitions from the state and city level are forming and they will likely have a strong presence at side events for COP23,” she adds. “Many groups are working at the local level around the world to try to meet the goal of the Paris Agreement.”

Emory is co-hosting an event on Thursday, November 16 at COP23, focused on ways to mitigate climate change impacts in the developing world. Saikawa will appear on a panel, along with John Seydel, director of sustainability for the city of Atlanta.

“We’ll be discussing how efforts at the city and state level in the United States might be replicated in other parts of the world,” Saikawa says.

This marks the third year in a row that Emory has sent a delegation to the U.N. climate talks.

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How lifeless particles can become 'life-like' by switching behaviors

Emory graduate student Guga Gogia slowly “salted” micron-sized particles into a vacuum chamber filled with plasma, creating a single layer of particles levitating above a charged electrode. He kept a low gas pressure, so the particles could move freely. “After a few minutes I could see with my naked eye that they were acting strangely," Gogia says.

By Carol Clark

Physicists have shown how a system of lifeless particles can become “life-like” by collectively switching back and forth between crystalline and fluid states — even when the environment remains stable.

Physical Review Letters recently published the findings, the first experimental realization of such dynamics.

“We’ve discovered perhaps the simplest physical system that can consistently keep changing behavior over time in a fixed environment,” says Justin Burton, Emory assistant professor of physics. “In fact, the system is so simple we never expected to see such a complex property emerge from it.”

Many living systems — from fireflies to neurons — switch behaviors collectively, firing on and then shutting off. The current paper, however, involved a non-living system: Plastic particles, tiny as dust specks, that have no “on” or “off” switches.

“The individual particles cannot change between crystalline and fluid states,” Burton says. “The switching emerges when there are collections of these particles — in fact, as few as 40. Our findings suggest that the ability for a system to switch behaviors over any time scale is more universal than previously thought.”

Watch a video to learn more and see the particles in action:


The Burton lab studies the tiny, plastic particles as a model for more complex systems. They can mimic the properties of real phenomena, such as the melting of a solid, and reveal how a system changes when it is driven by forces.

The particles are suspended in a vacuum chamber filled with a plasma — ionized argon gas. By altering the gas pressure inside the chamber, the lab members can study how the particles behave as they move between an excited, free-flowing state into a jammed, stable position.

The current discovery occurred after Emory graduate student Guram “Guga” Gogia tapped a shaker and slowly “salted” the particles into the vacuum chamber filled with the plasma, creating a single layer of particles levitating above a charged electrode. “I was just curious how the particles would behave over time if I set the parameters of the chamber at a low gas pressure, enabling them to move freely,” Gogia says. “After a few minutes I could see with my naked eye that they were acting strangely.”

From anywhere between tens of seconds to minutes, the particles would switch from moving in lockstep, or a rigid structure, to being in a melted gas-like state. It was surprising because the particles were not just melting and recrystallizing but going back and forth between the two states. 

“Imagine if you left a tray of ice out on your counter at room temperature,” Gogia says. “You wouldn’t be surprised if it melted. But if you kept the ice on the counter, you would be shocked if it kept turning back to ice and melting again.”

Gogia conducted experiments to confirm and quantify the phenomenon. The findings could serve as a simple model for the study of emerging properties in non-equillibrium systems.

“Switching is an ubiquitous part of our physical world,” Burton says. “Nothing stays in a steady state for long — from the Earth’s climate to the neurons in a human brain. Understanding how systems switch is a fundamental question in physics. Our model strips away the complexity of this behavior, providing the minimum ingredients necessary. That provides a base, a starting point, to help understand more complex systems.”

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CDC funds Emory project to automate analysis of mixed strains of antibiotic-resistant bacteria

An electron micrograph shows human immune system cells attacking methicillin-resistant Staphylococcus aureus (MRSA). MRSA is an example of antibiotic-resistant bacteria that can occur in multiple strains in an infection, further complicating diagnosis, treatment and interventions.

By Carol Clark

The Centers for Disease Control and Prevention (CDC) awarded $380,000 to three Emory University faculty to develop and refine a promising technique to detect and respond to threats from drug-resistant pathogens.

The grant investigators include Lars Ruthotto and Ymir Vigfusson — both assistant professors in the Department of Mathematics and Computer Science — and Rebecca Mitchell, a visiting professor with a joint appointment in the Department of Mathematics and Computer Science and the Nell Hodgson Woodruff School of Nursing. 

The trio is developing a method to quickly and cost-effectively diagnose multiple strains of antibiotic-resistant bacteria within a single biological sample.

“This project harmonizes our different scientific specialties,” Vigfusson says. He is a computer scientist who develops software and programming algorithms that work at scale, while Ruthotto is a mathematician who focuses on solving inverse problems. Mitchell is a veterinarian and epidemiologist experienced in gathering biological samples and testing them for pathogens. 

Antibiotic-resistant infections are a growing national and global problem, causing at least two million illnesses and 23,000 deaths in the United States annually, according to the CDC.

The Emory grant is part of a $9 million package of CDC funding announced today, including awards to projects at 25 leading research institutions around the country that are exploring gaps in knowledge about antibiotic resistance and piloting innovative solutions in the healthcare, veterinary and agriculture industries. The work complements broader CDC efforts to support known strategies for protecting people and slowing antibiotic resistance, collectively known as the CDC Antibiotic Resistance Solutions Initiative.

The Emory project seeks to tame the complexity of analyzing multiple infections within a biological specimen, from a drop of blood to a fecal sample. In the case of a widespread outbreak of antibiotic-resistant E. coli for instance, it would be useful to quickly determine whether fecal samples contained multiple strains of the bacteria and what those strains were, in order to more rapidly trace the sources of the outbreak and design effective interventions.

It is costly and labor-intensive, however, to culture biological samples at the local level, and then send them to the CDC for testing. And if multiple strains of a pathogen are within a single sample, only some strains that are present may grow in the culture while other strains may be missed.

“It’s a challenge to deal with samples containing mixed strains of a pathogen in a lab setting,” Mitchell says. “You have to do a large amount of work to get the finer gradations of what species of pathogens are present, and in what proportions.”

The Emory researchers are striving to balance accuracy with the need to simplify and streamline the process. Their method eliminates labor-intensive, technical steps, such as culturing the sample. “We want to automate the process so that you need less expertise at the local level, and so that data coming from individual states can be easily integrated into a central system,” Mitchell explains.

They use multiple short polymorphic regions in the genome to look for genetic variations among the DNA templates present within a biological sample. In the case of antibiotic-resistant bacteria, the number of reference sites ranges between the hundreds to the thousands, depending on the specific bacteria targeted.

“We’ve developed an algorithm and software and mathematical models to rapidly run these comparisons and estimate the number of strains in a single sample, and the percentage of each,” Ruthotto says. “Now we are trying to quantify the accuracy of this estimate, which is a mathematical challenge. The grant gives us the resources to refine our method for real-world applications.”

The ultimate goal is to develop a system that will work not just on antibiotic-resistant bacteria, but for mixed-strains of any pathogen within a biological sample. In a separate project, for example, Mitchell and Vigfusson are applying the method to test for multiple strains of the malaria parasite within a blood sample.

“Quickly teasing apart mixed-strain samples is a big challenge in public health, and it’s essential in order to plan effective interventions,” Mitchell says.

“We’re using math and computer science to draw more information from a single biological sample than was previously practical,” Vigfusson says. “We hope that our method could turn into a work engine that helps to understand multiple-strain infections and makes an impact on public health.”

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Responding to climate change

By Martha McKenzie
Emory Public Health

Climate change. Partisan politicians debate its reality, and many citizens see it as a faraway threat, something that endangers the future of polar bears but not them personally.

The health effects of global warming, however, are already being felt. Extreme weather events such as wildfires, droughts, and flooding are becoming more frequent, resulting in more injuries, deaths, and relocations. Heat and air pollution are sending people with asthma and other respiratory ailments to the emergency room. Diseases carried by mosquitoes, fleas, and ticks are expanding their territory—dengue has become endemic in Florida, Lyme disease has worked its way up to Canada and over to California, and some fear that malaria may re-emerge in the U.S.

Tie these health burdens—which are only likely to worsen—with the current administration’s decision to pull out of the Paris climate agreement and dismantle environmental regulations, and the call to action becomes more urgent. “The federal government’s actions might be a headwind from a funding perspective, but they are also very much a tailwind from an inspiration and motivation perspective,” says Daniel Rochberg, an instructor in environmental health who worked for the U.S. State Department as special assistant to the lead U.S. climate negotiators under presidents Bush and Obama. “As others have said, ‘We are the first generation to feel the sting of climate change, and we are the last generation that can do something about it.’ We have to get busy doing something about it.”

Rollins School of Public Health has gotten busy. Faculty researchers are building the science of climate impacts, strategies for reducing greenhouse gas emissions, and approaches for increasing resilience to climate change. Climate@Emory, a university-wide organization of concerned students, faculty, and staff, is partnering with other academic institutions, industries, and governments to support education and climate remediation efforts. Through Climate@Emory’s initiative, Emory University is an accredited, official observer to the UN climate talks and has sent students and faculty to the climate conferences in Paris in 2015 and in Marrakech in 2016. And, of course, Rollins is educating the next generation of scientists who will be dealing with the fallout of today’s climate decisions.

“For environmental scientists, it’s a challenging climate,” says Paige Tolbert, O. Wayne Rollins Chair of Environmental Health. “That means we have to be creative, because we can’t step aside and wait four years. It’s more critical than ever that we keep moving forward and make whatever contributions we possibly can.”

Read more in Emory Public Health.

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NSF awards Emory's Center for Selective C-H Functionalization $20 million

"We’ve developed advanced catalysts that allow us to control which carbon-hydrogen bond within a molecule will react and when," says Huw Davies, director of the Center for Selective C-H Functionalization. (Graphic/photo by Stephen Nowland and Dan Morton)

By Carol Clark

The National Science Foundation has awarded another $20 million to Emory University’s Center for Selective C-H Functionalization, to fund the next phase of a global effort to revolutionize the field of organic synthesis.

“Our center is at the forefront of a major shift in the way that we do chemistry,” says Huw Davies, professor of chemistry at Emory and the director of the Center for Selective C-H Functionalization (CCHF). “This shift holds great promise for creating new pathways for drug discovery and the production of new materials to benefit everything from agriculture to electronics.”

The CCHF began as an NSF Center for Chemical Innovation in 2009, with a seed grant of $1.5 million and four collaborating universities. In 2012, the NSF awarded the CCHF its first $20 million, enabling it to grow to encompass 16 U.S. institutions and seven industrial affiliates, including six major pharmaceutical companies and one of the largest U.S. chemical suppliers. The center also built global connections with major players in C-H functionalization in Japan, South Korea and the U.K. 

The CCHF has led the way for explosive growth in the field of C-H functionalization, publishing more than 200 papers on the topic through its collaborators. It has developed dozens of new catalysts for C-H functionalization, including four major classes from the Huw Davies group.

“The past five years we’ve developed the fundamentals for C-H functionalization and documented that the concept is viable,” Davies says. “Now we’re ideally positioned to maximize the further development of this chemistry and move forward to apply it.”

Huw Davies, right, in his lab with Emory post-doctoral fellow Sidney Wilkerson-Hill, left, and Emory junior Patricia Chi Lin. The CCHF has developed dozens of new catalysts for C-H functionalization, including four major classes from the Davies group. (Photo by Stephen Nowland, Emory Photo Video)

Traditionally, organic chemistry has focused on the division between reactive, or functional, molecular bonds and the inert, or non-functional bonds carbon-carbon (C-C) and carbon-hydrogen (C-H). The inert bonds provide a strong, stable scaffold for performing chemical synthesis with the reactive groups. C-H functionalization flips this model on its head. 

“We’ve devised ways to make C-H bonds react so that they become functional,” Davies says. “And we’ve reached the stage where it is no longer the molecule itself that determines the process of the reaction — we’ve developed advanced catalysts that allow us to control which carbon-hydrogen bond within a molecule will react and when.”

C-H functionalization opens unexplored chemical space by taking petroleum byproducts, which have a lot of carbon-hydrogen bonds, and transforming them from waste into useful materials. It also strips out steps from the linear process of traditional organic synthesis, making it faster and more efficient.

The CCHF is not only transforming organic synthesis — it’s also creating new models for the way that organic chemistry is taught and that labs conduct research. Where previously individual labs tended to work in isolation to tackle problems, the CCHF has broken down walls across specialties, institutions and even countries to collectively take on the remaining challenges of selective C-H functionalization.

“We’ve got this incredible collaborative environment where organic chemists aren’t just sharing results — they’re sharing ideas,” Davies says. “That’s rare. And we’ve expanded that environment beyond our network of universities to also engage the pharmaceutical industry.”

In 2015, the CCHF launched an online symposia on recent advances in C-H functionalization. More than 1,000 graduate students and chemistry faculty from up to 45 countries join the symposia, held about four times a year, via the Internet.

“We have leading voices in the field give these free talks that are easy to join live and participate in,” Davies says. “The aim is to further expand the field of C-H functionalization by introducing it to graduate students and other chemists around the world.”

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Why plants represent untapped potential for innovative drug discovery

Northeastern chemistry graduate student John de la Parra poses with an aloe plant. He is collaborating with Emory ethnobotanist Cassandra Quave to explore the medicinal properties of plants. Photo by Matthew Mondoono/Northeastern University.

By Allie Nicodemo,
Northeastern University

The field of medicine has come a long way from using heroin as a cough remedy or magnet therapy to improve blood flow. These outdated methods were put to bed decades ago. But there are plenty of ancient medicinal practices that have stood the test of time. In fact, many of the life-saving pharmaceuticals we rely on today are derived from plants first discovered by indigenous communities.

Ethnobotany is the scientific study of traditional plant knowledge. It’s what gave us morphine, aspirin, and ephedrine, to name a few. And there is still untapped potential.

In a new paper published by Trends in Biotechnology, Northeastern University doctoral candidate John de la Parra and Emory University medical botanist Cassandra Quave described a new field called ethnophytotechnology. It’s the use of plant biotechnology to improve the plant-based drug discovery pipeline.

“New production, engineering, and analysis methods have made it easier to meet scientific challenges that have confronted traditionally used plant-derived medicines,” says de la Parra, who is earning his doctorate in chemistry. “It is our hope that as the field expands, rich troves of indigenous knowledge can find prominence within innovative drug discovery and production platforms.”

Quave and de la Parra are examining the vast opportunities for ethnobotany and ethnophytotechnology to promote new drug discovery and solve health challenges.

Read the full story about their recent paper on the Northeastern news site.

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To boldly go where public health hasn't gone before

"Hopefully, Emory will make a mark in NASA history," says Yang Liu, associate professor of environmental health. (NASA photo)

From Rollins Magazine

Rollins School of Public Health researchers will soon take their research into orbit, partnering with the National Aeronautics and Space Administration (NASA) in a new satellite mission to study air pollution.

NASA chose Rollins as a joint recipient of its $100 million award — $2.3 million of which will come to Rollins — to study the effects of air pollution on the population through a satellite mission, according to Yang Liu, associate professor of environmental health. He noted that this is the first time a NASA space mission has incorporated a public health component.

"We're the scientific guinea pig," Liu said.

The Rollins research group, led by Liu, co-created the project idea with NASA's Jet Propulsion Laboratory (JPL). The mission will construct and use a Multi-Angle Imager for Aerosols (MAIA) device to record airborne particulate matter, which will collect data on the effects of pollution on public health from at least 10 locations with major metropolitan areas.

Once constructed by JPL, the MAIA device will be mounted on a compatible Earth-orbiting satellite. "Even though it's a small mission, it's actually the first ever in which we get to work with NASA engineers to build public health into the DNA of this instrument," Liu said.

The Rollins team will analyze the data to make predictions about public health issues such as birth outcomes and cardiovascular disease. The team will also serve as the public health liaison between JPL and other institutions in the complete research group. Recruited by Liu, the complete group has teams at University of California, Los Angeles, Harvard University, University of British Columbia, and University of Dalhousie.

Because the device will orbit via satellite, it will provide a more holistic view of air pollution data than the commonly used ground monitors.

"It's very difficult to cross to a completely different scientific community and convince them that this mission is not only worthwhile but also feasible," Liu said. "Hopefully, Emory will make a mark in NASA history."

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Students advocating for academic science

PhD candidates Crystal Grant, left, and Joshua Lewis are vocal advocates for scientific research at universities, but neither is ready to commit to academic careers due to uncertainty about good jobs. Last summer, they made their case to congressional aides from the Georgia delegation. (Kay Hinton)

By Hal Jacobs
Emory Magazine

Call it the 800-pound gorilla in the lab.

Crystal Grant, a graduate student in Emory's Genetics and Molecular Biology program in the Graduate Division of Biological and Biomedical Sciences (GDBBS), faced it while studying how people’s DNA changes with age.

Graduate student Joshua Lewis of the GDBBS Biochemistry, Cell and Developmental Biology program saw its shadow while researching how cells stick to neighbor cells— information that could lead to understanding how cancer cells metastasize.

The problem weighed so heavily on Chelsey Ruppersburg, who graduated with a PhD in 2016, that she changed career directions after racing to earn a doctorate in cell biology in only four years, rather than the usual six or seven.

The situation is readily apparent to anyone who works in an academic lab. Research is a slow, steady, incremental process; funding is erratic, inconsistent, boom and bust. Principal investigators must tear themselves away from working with students to chase fewer National Institutes of Health (NIH) and National Science Foundation (NSF) grants. Hiring new students and staff is fraught because funding for their positions is a moving target.

Meanwhile, a steady stream of graduate students—vital to every academic lab—compete for rarer faculty positions while being tempted by more lucrative private industry jobs or opportunities abroad.
Postdoctoral fellowships, an important transitional step from student to professor, have become a port of call that may stretch into years of low pay and uncertainty for scientists who hoped to settle down after a decade-plus of intense schooling.

But as the challenge grows steeper, the same young scientists who are most affected are also trying to solve it.

Read more in Emory Magazine.

Key connection in neural code of 'love' uncovered in vole study

New research probes the neural circuitry responsible for pair bonding in prairie voles.

From Woodruff Health Sciences

A team of neuroscientists from Emory University's Silvio O. Conte Center for Oxytocin and Social Cognition has discovered a key connection between areas of the adult female prairie vole's brain reward system that promotes the emergence of pair bonds. Results from this study, published this week in Nature, could help efforts to improve social abilities in human disorders with impaired social function, such as autism.

This Conte Center study is the first to find the strength of communication between parts of a corticostriatal circuit in the brain predicts how quickly each female prairie vole becomes affiliative with her partner; prairie voles are socially monogamous and form lifelong bonds with their partners. Additionally, when researchers boosted the communication by using light pulses, the females increased their affiliation toward males, thus further demonstrating the importance of this circuit's activity to pair bonding in prairie voles.

"Prairie voles were critical to our team's findings because studying pair bonding in humans has been traditionally difficult," says co-lead author Elizabeth Amadei. "As humans, we know the feelings we get when we view images of our romantic partners, but, until now, we haven't known how the brain's reward system works to lead to those feelings and to the voles' pair bonding."

Building upon previous work in prairie voles that demonstrated brain chemicals, such as oxytocin and dopamine, act within the medial prefrontal cortex and nucleus accumbens to establish a pair bond, the team set out to address finding the precise neural activity leading to a pair bond. The researchers used probes to listen to neural communication between these two brain regions and then analyzed activity from individual female prairie voles as they spent hours socializing with a male - a cohabitation period that normally leads to a pair bond.

The team discovered that during pair bond formation, the prefrontal cortex, an area involved in decision-making, helps control the rhythmic oscillations of neurons within the nucleus accumbens, the central hub of the brain's reward system. This suggests a functional connection from the cortex shapes neurons activity in the nucleus accumbens.

The team then noticed individual voles varied in the strength of this functional connectivity. Importantly, each subject with stronger connectivity showed more rapid affiliative behavior with her partner, measured as side-by-side huddling contact. Furthermore, the pair's first mating, a behavior that accelerates bonding in voles, strengthened this functional connection, and the amount of strengthening correlated with how quickly the animals subsequently huddled.

"It is remarkable there are neural signatures of a predisposition to begin huddling with the partner. Similar variation in corticostriatal communication could underlie individual differences in social competencies in psychiatric disorders in humans, and enhancing that communication could improve social function in disorders such as autism," says Larry Young, co-author and director of the Conte Center and chief of the Division of Behavioral Neuroscience and Psychiatric Disorders at Yerkes National Primate Research Center.

The study results led the team to ask more questions, including whether communication between the prefrontal cortex and nucleus accumbens not only correlates with huddling but also causally facilitates it. To answer this, the researchers used optogenetics, a technique that allowed them to enhance communication between the brain areas using light, and enhanced communication between the prefrontal cortex and nucleus accumbens of female voles during a brief cohabitation without mating, which is not conducive to pair bonding.

The team discovered optogenetically stimulated animals showed greater preference toward partners compared to a stranger male when given a choice the following day.

"It is amazing to think we could influence social bonding by stimulating this brain circuit with a remotely controlled light implanted into the brain," says Zack Johnson, co-lead author. The study results identify an important reward circuit in the brain that is activated during social interactions to facilitate bond formation in voles.

"Now, we want to know if oxytocin regulates functional connectivity and how circuit activity changes the way the brain processes social information about a partner," says senior author Robert Liu, associate professor in Emory's Department of Biology. "Our team's work is an example of a larger effort in neuroscience to better quantify how brain circuits function during natural social behaviors. Our goal is to promote better neural communication to boost social cognition in disorders such as autism, in which social functioning can be impaired," Liu adds.

Amadei and Johnson were both graduate students who attained their PhD's this year. Additional Emory-based co-authors are graduate students Yong Jun Kwon and Varun Saravanan, undergraduate student Aaron Shpiner, and Wittney Mays, Steven Ryan, PhD, Hasse Walum, PhD, and Donald Rainnie, PhD.

The goal of the Silvio O. Conte Center for Oxytocin and Social Cognition is to improve human health by leading coordinated and rigorous research programs to discover the neural mechanisms by which oxytocin modulates social cognition. The research represents a unique collaboration among Emory University's Emory College of Arts and Sciences, School of Medicine and Yerkes National Primate Research Center, and the Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University.

Georgia Climate Project creates state 'climate research roadmap'

Environmental sciences instructor Daniel Rochberg, chief strategy officer for Climate@Emory, says the Georgia Climate Research Roadmap aims to create "Georgia's Top 40," a set of targeted research questions to help the state understand and address climate change. (Emory Photo/Video)

By Kimber Williams
Emory Report

Scientists, researchers and environmental experts from across the state convened at Emory last week to draft the “Georgia Climate Research Roadmap” — a set of targeted research questions that could help Georgia better understand and address one of the century’s defining challenges.

The goal of the May 22-23 gathering was to formulate “Georgia’s Top 40,” key climate research questions that could eventually aid decision-making and planning for Georgia policymakers, scientists, communities and service organizations.

An initiative of the Georgia Climate Project, the roadmap was a response to the fact that communities across Georgia are already exploring strategies to address the impact of climate change, says Daniel Rochberg, chief strategy officer for the Climate@Emory initiative and an instructor in the Rollins School of Public Health and Emory College of Arts and Sciences, where he focuses on climate change and sustainable development.

Some Georgia communities are actively assessing vulnerabilities and strategies to build resilience to potential climate change impact, while others are developing technologies and policies to begin reducing emissions, according to Rochberg, who has also worked for the U.S. State Department as special assistant to the lead U.S. climate negotiators under presidents Bush and Obama.

“To inform this work, decision-makers at all levels need credible and relevant information from across the natural, applied and social sciences,” says Murray Rudd, an associate professor in Emory’s Department of Environmental Sciences and member of the climate research roadmap steering committee. “The Georgia Climate Research Roadmap seeks to fulfill this need by identifying the key research questions that, if answered, can lay the groundwork for the state and its residents to take effective, science-based climate action,” he says.

Read the full story in Emory Report.

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Climate change is in Atlanta's air

"We're all partly responsible for our local air quality," says Emory graduating senior Emily Li. "Even if we don't hold ourselves accountable, our health will." (Emory Photo/Video)

By Carol Clark

Emory 2017 graduate Emily Li is leaving Atlanta this summer, but her student research will continue to have a presence here. For her undergraduate thesis, Li investigated the effects of shifting weather patterns on the air quality of Atlanta and the region — and how that relates to human health. She’s compiled her findings into a web site, Climate Change is in the Air, as a resource for local residents. 

“The web site explains some of the science involved, but it’s not just statistics,” Li says. “It also tells stories of real people. I wanted to put faces on these complex, scientific processes and explain how individuals are being directly affected by climate change, right now.”

In addition to science and stories from real people, the site offers solutions — what communities and individuals can do to address the issue.

Li, who majored in Environmental Sciences and English, sampled classes from a range of disciplines during college. No matter what the course, however, climate change kept coming up. “I think that it’s the most important issue that we face today, and I want to be part of the solution,” she says.

As a junior, Li took a course called Environmental Journalism, taught by Sheila Tefft, and realized that she could combine her two passions: Science and communication.

The web site focuses on how climate change is connected to Atlanta’s air quality, and how air quality is connected to the health of everyone living here. “Everybody has to breathe the air,” Li says. “We each need about 50 pounds of air a day and we can only go without it for about five minutes. Air is what we use the most and need the most to survive.”

The air pollutants that are contributing to a warming climate also contribute to problems of human health across the body — from the functions of lung and bronchial airways to cardiovascular diseases and central nervous system disorders. For the web site, Li concentrated on the respiratory health impacts of aeroallergens, wildfire emissions and ground-level ozone.

In lush Atlanta, a city famous for its “pollen explosions,” a warming climate may mean a longer exposure to pollen from many plants. Li tells the story of a fellow Emory student with a range of plant allergies to show the impact that high pollen counts can have on an individual’s life. “It’s hard to enjoy a nice spring day when you have to take a nap afterwards just for breathing the air,” she writes.

Hot, dry conditions also contribute to wildfires in Georgia, including an ongoing blaze in the Okefenokee National Wildlife Refuge. Hundreds of firefighters are currently battling the fire as it threatens to spread beyond the swamp to nearby communities.

To personalize the impact of the wildfire emissions, Li interviewed a firefighter from north Georgia. She described his experience of a minor smoke inhalation episode: “The condition is first initiated by a deep-set exhaustion: He’s already usually hot, sweaty and tired out from the firefighting work. Overwhelmed, his respiratory system begins to let down its defenses. Then he starts to get a tightness in his chest, like his upper body is being squeezed by an invisible fist. It becomes hard for him to fully catch his breath, and he can feel a distinct obstruction in his windpipe with every attempt to suck air into his lungs. At the same time, his energy levels plummet dangerously.”

The firefighter explained to Li: “With wildfire, typically there’s a lot of walking that has to happen and a lot of strenuous activity getting to remote areas. It’s just not possible or feasible to carry air packs or self-contained breathing apparatus into the wilderness or remote areas and sustain that air supply.”

The topic of ground-level ozone is also covered on the web site, although the personal story for that section remains under construction.

Li is leaving Atlanta to pursue a masters degree in education from the University of Pennsylvania, but she plans to keep adding to the site — and perhaps expand it to encompass other cities across the country.

“My goal is to create an immersive experience that people can not just learn from, but connect to,” Li says. “I want to bridge the emotional distance between people and the science of climate change.” 

The solutions offered on the site are a critical part of that goal, she adds. “One of my main suggestions is to just stay informed and aware and spread that awareness any way that you can,” Li says. “The more people that understand the problem, the better.”

Atlanta residents also have a chance to make a difference as the Atlanta Regional Commission works on a Regional Transportation Plan aimed at meeting Clean Air Act requirements. “Anyone can join the conversation to help make the plan a reality,” Li says.

Researching the potential impacts of climate change was overwhelming at times but ultimately rewarding, Li says. “Working on this project has made me much more deliberate in my actions. It’s also made me aware of not only how I can contribute to solutions to climate change, but how I can help other people stay hopeful and helpful so they can take action as well.”

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