Two assistant professors from the Georgia Tech College of Sciences, Jenny McGuire and Lutz Warnke, have received 2020 Faculty Early Career Development (CAREER) Awards from the National Science Foundation (NSF).

As NSF's most prestigious award, the CAREER program supports early-career faculty who integrate excellence in education and research, serve as academic role models, and lead advances in the mission of their organization. The award comes with a federal grant for research and education activities for five consecutive years.

“Never underestimate what a National Science Foundation CAREER Award can do for a young scientist,” says Julia Kubanek, College of Sciences Associate Dean for Research. “Many of our senior faculty at Georgia Tech started their funding history as NSF CAREER awardees. They act as a springboard for faculty success in so many ways.”

Kubanek, who is also a professor in Biological Sciences and in Chemistry and Biochemistry, emphasizes the length of the grant: five years. “The funding that comes with an NSF CAREER award provides substantial support to get a faculty member’s fresh and unique research ideas off to a strong start.” The NSF also likes to see research and education combined as a way to inspire creative teaching methods that give students a more hands-on approach.

For Jenny McGuire, assistant professor in Biological Sciences and in Earth and Atmospheric Sciences, the CAREER grant will support paleoecological research exploring how plants and animals respond to environmental change and allow her to test these theories in a deep, ancient cave in Wyoming — where clues left by past environmental shifts could provide insights for current and future climate change.

For Lutz Warnke, assistant professor in Mathematics, the CAREER grant will support fundamental research at the interface of discrete mathematics and probability, exploring the fascinating properties of random networks (or graphs) and their remarkable applications in graph theory, extremal combinatorics, and other areas.

Jenny McGuire: Do Species Track Climate? Paleoecology to Disentangle Niche Dynamics

Since 2015, Jenny McGuire has spent her summers rappelling 30 feet into Wyoming’s Natural Trap Cave, digging for fossils that can provide some insight into the impact past climatic and environmental changes had on plant and animal species 20,000-30,000 years ago. McGuire’s work looks at how those changes in climate might have affected animal migration patterns. 

“I was incredibly excited to get the award, because it is going to allow me to do some really exciting work,” says McGuire, who is also a past NSF Division of Environmental Biology awardee. “My ​project looks at the climate fidelity that different plant and animal species exhibited during past periods of climate change, so that we can characterize the extent to which they will respond to future change. By understanding how species respond to changing climate, we can identify which species and strategies to prioritize to conserve biodiversity going forward.”

Along with increasing our understanding of ecosystem and species-level responses to climate change and drought, McGuire’s spelunking expeditions and research help educate students and communities about how climate affects ecosystems.

Many of McGuire’s cave finds are brought back to Georgia Tech for what she calls Fossil Fridays, when the public is invited to help sift through the gravel and dirt to look for fossils. These “fossil discovery opportunities” reach people from across the broader Atlanta community, as well as East African undergraduate students who participate in workshops facilitated by the Conservation Paleobiology in Africa program.

“We are living in a time of rapid change,” McGuire notes. “Given the extent of the change, it is hard to predict how ecosystems are going to respond by observing snapshots of time. We use organisms' responses to past climatic and environmental changes to determine how things will play out, given the extreme changes that are anticipated.”

Lutz Warnke: Understanding the Evolution of Random Graphs with Complex Dependencies: Phase Transition and Beyond

Lutz Warnke — who is also a recipient of the 2014 Richard-Rado-Prize, the 2016 Dénes König Prize, a 2018 Sloan Research Fellowship, and a NSF Division of Mathematical Sciences award — is fascinated by graph processes and networks, which are useful mathematical abstractions that consist of collections of points with links, or line-segments, connecting them. The more links you add, the more complex those networks become.

“Time-evolving random networks/random graph processes play an important role in several branches of mathematics and applied sciences, including statistical physics, complex networks, and extremal combinatorics,” Warnke says. “Unfortunately, for these processes, there is nowadays a widening gap between simulation-based results and theoretical understanding. I hope to develop new mathematical theory for such random graph processes, in order to better understand their properties, improve existing methods of analysis, and rigorously justify their applications.”

Warnke is using these random graph processes to attack difficult open problems in combinatorics. He explains "they provide a systematic way to give powerful probabilistic guarantees for hard-to-answer deterministic questions, such as the construction of complex graphs with unusual properties/constraints. I am particularly fascinated by the fact that the usage of randomness helps in extremal combinatorics and graph theory, and by developing new ways of analysis/new random processes I am trying to significantly increase the range of combinatorial applications."

The CAREER grant will also allow him to spend more time on the phase transition of random graphs. He explains, “This refers to a sudden change of their typical properties, as we add more and more links to the graph (similar to how the state of water changes as we increase the temperature). I am trying to understand whether the phase transition of a wide variety of random graph processes share essential ‘universal’ features, as predicted by the profound universality paradigm from physics.”

“It is a great honor to receive the NSF CAREER award,” says Warnke. “I gratefully acknowledge this recognition and support from NSF, which will now help/allow me to further advance my research program, and pursue some of the most challenging problems in probabilistic combinatorics.”

McGuire and Warnke are among a number of 2020 NSF CAREER awardees representing Georgia Tech. Learn more about Jenny McGuire and Lutz Warnke, and about the CAREER Program.

Extracting nectar from flowers that may be dancing in the wind requires precise, millisecond timing between the brain and muscles.

By capturing and analyzing nearly all of the brain signals sent to the wing muscles of hawk moths (Manduca sexta), which feed on such nectar, researchers have shown that precise timing within rapid sequences of neural signal spikes is essential to controlling the flight muscles necessary for the moths to eat.

The research shows that millisecond changes in timing of the action potential spikes, rather than the number or amplitude of the spikes, conveys the majority of information the moths use to coordinate the five muscles in each of their wings. The importance of precise spike timing had been known for certain specific muscles in vertebrates, but the new work shows the general nature of the connection. 

“We were able to record simultaneously nearly every signal the moth’s brain uses to control its wings, which gives us an unprecedented and complete window into how the brain is conducting these agile and graceful maneuvers,” said Simon Sponberg, Dunn Family Professor in the School of Physics at the Georgia Institute of Technology. “These muscles are coordinated by subtle shifts in the timing at the millisecond scale rather than by just turning a knob to create more activity. It’s a more subtle story than we might have expected, and there are hints that this may apply more generally.”

The research was reported Dec. 16 in the journal Proceedings of the National Academy of Sciences. The work was supported by the National Science Foundation, the Esther A. & Joseph Klingenstein Fund, and the Simons Foundation.

Researchers Joy Putney, Rachel Conn and Sponberg set out to study how the brain coordinates agile activities such as running or flying that require compensating for perturbations in the air or variations on the ground. While the size of the signals could account for gross control of the behavior, the fine points of choreographing the tasks had to come from elsewhere, they reasoned.

Recording motor control signals in humans and other vertebrates would be a daunting task because so many neurons are used to control so many muscles in even simple behaviors. Fortunately, the researchers knew about the hawk moth, whose flight muscles are each controlled by a single or very few motor neurons. That allowed the researchers to study neural signals by measuring the activity of the corresponding muscles, using tiny wires inserted through the insect’s exoskeleton.

Putney and Conn determined the location of each wing muscle inside the moth exoskeleton, and learned where to create tiny holes for the wires — two for each muscle — that capture the signals. After inserting the wires in the anesthetized moths, the graduate students closed the holes with superglue to hold the wires in place. Connections to a computer system allowed recording and analysis.

“The first time I did the surgery by myself, it took six hours,” said Putney. “Now I can do it in under an hour.”

While connected to the computer, the moths were able to fly on a tether as they viewed a moving 3D-printed plastic flower. To measure the torque forces the moths created as they attempted to track the flower, the wired-up moths were suspended from an accelerometer.

The torque information was then correlated with the spiking signals recorded from each wing muscle.

The importance of the work relates to the completeness of the signal measurement, which brought out the importance of the timing codes to what the moth was doing, Putney said.

“People have recorded lots of muscles together before, but what we have shown is that all of these muscles are using timing codes,” she said. “The way they are using these codes is consistent, regardless of the size of the muscle and how it is attached to the body.”

Indeed, researchers have seen hints about the importance of precision timing in higher animals, and Sponberg believes the hawk moth research should encourage more study into the role of timing. The importance and prevalence of timing across the moth’s motor program also raises questions about how nervous systems in general create precise and coordinated motor commands.

“We think this raises a question that can’t be ignored any longer — whether or not this timing could be the real way that the brain is orchestrating movement,” Sponberg said. “When we look at specific signals in vertebrates, even up to humans, there are hints that this timing could be there.”

The study could also lead to new research on how the brain produces the agile motor control needed for agile movement.

“Now that we know that the motor control is really precise, we can start trying to understand how the brain integrates precise sensory information to do motor control,” Sponberg said. “We want to really understand not only how the brain sets up signals, but also how the biophysics of muscles enables the precise timing that the brain uses.”

This material is based upon work supported by National Science Foundation Graduate Research Fellowships DGE-1650044 and DGE-1444932, an NSF CAREER award (1554790), and a Klingenstein-Simons Fellowship Award in the Neurosciences. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsoring organization.

CITATION: Joy Putney, Rachel Conn, and Simon Sponberg, “Precise timing is ubiquitous, consistent and coordinated across a comprehensive, spike-resolved flight motor program.” (Proceedings of the National Academy of Sciences, 2019.) https://www.pnas.org/content/early/2019/12/11/1907513116

Research News
Georgia Institute of Technology
177 North Avenue
Atlanta, Georgia 30332-0181  USA

Media Relations Contact: John Toon (404-894-6986) (jtoon@gatech.edu)

Writer: John Toon

While it’s largely business as usual in Cobb’s cities following Tuesday’s municipal elections, Smyrna’s government faces significant change....It would also mean newcomer Lewis Wheaton, a 42-year-old Georgia Tech professor who won 57% of the preliminary vote in the Ward 7 race, would be the only person of color on the council.

At Georgia Tech, members and trainees of the Center for Microbial Dynamics and Infection discuss the identification of pathogen essential genes during coinfections, and how coral management can improve coral defenses against pathogens. Guests were Marvin Whiteley, Gina Lewin, Deanna Beatty, Mark Hay, and Frank Stewart.

Fire ants build living rafts to survive floods and rainy seasons. Georgia Tech scientists are studying if a fire ant colony’s ability to respond to changes in their environment during a flood is an instinctual behavior and how fluid forces make them respond. Hungtang Ko and David Hu will present the science behind this insect behavior, focusing their discussion on how the living raft changes size under various environmental conditions at the American Physical Society’s Division of Fluid Dynamics 72nd Annual Meeting on Nov. 26.

By A. Maureen Rouhi

Examine your hands. The right is a mirror image of the left. They look very similar, but you know they’re not when you try to put your left hand inside a right glove.

The molecules of life have a similar handedness. Proteins for example are like your left hand, made up of amino acids that are all left-handed. This phenomenon is called chirality. How chiral systems emerged is one of the key questions of origins-of-life research.

Many explanations have been proposed. Now a Georgia Tech team examining the problem suggests that stability is what drove the emergence of chiral systems. Led by Jeffrey Skolnick, a professor in the School of Biological Sciences, the team includes  research scientists Hongyi Zhou and Mu Gao. The work was supported in part by the Division of General Medical Sciences of the National Institutes of Health (NIH Grant R35-118039) and published on Dec. 10, 2019, in PNAS.

They reached their conclusion from computer simulations examining the stability and properties of a prepared protein library made up of  

• nonchiral proteins, containing a 1:1 ratio of right- (D) and left-handed (L) amino acids, also called demi-chiral;  
• nonchiral proteins containing 3:1 and 1:3 of D and L amino acids; and
• chiral proteins containing all D and all L amino acids. 

Their simulations showed that nonchiral proteins, even the demi-chiral ones, have many properties of chiral proteins. They fold and form cavities just like ordinary proteins. They could have performed many of the biochemical functions of ordinary proteins, especially the most ancient and essential ones. These nonchiral proteins also can adopt the structures of contemporary proteins including ribosomal proteins, necessary for protein transcription.

“This ability of nonchiral proteins to fold and function might have been an essential prerequisite for the life on Earth,” says Eugene Koonin, a senior investigator at the National Center for Biotechnology Information, in the National Institutes of Health. “If so, this result is a truly fundamental finding that contributes to our understanding of the origins of life.”

However, nonchiral proteins have fewer hydrogen bonds than those made of all D or all L amino acids. The demi-chiral ones have the fewest. Thus chiral proteins are much more stable than demi-chiral ones. “The biochemistry of life as we know it likely results from stability driven by hydrogen bonds,” says Skolnick, who is a member of the Parker H. Petit Institute of Bioengineering and Bioscience.

The PNAS study examines the properties of proteins from the point of view of physics alone, without the intervention of evolution, Skolnick says. “It explains how the chemistry of life emerged from basic physical principles. It also strongly suggests that simple life might be quite ubiquitous throughout the universe.”

“I wish to understand how life emerged and to know its design principles,” Skolnick says. “On the most academic level, I wish to explain the origin of life based on physics with well-defined testable ideas.”

The newly published “work offers a non-intelligent-design perspective as to how the biochemistry of life might have gotten started,” Skolnick says. “It shifts the emphasis from evolution to the inherent physical properties of proteins. It removes that chicken-and-egg quandary that chiral RNA is required to produce chiral proteins. Rather, such excess chirality is shown to emerge naturally from a nonchiral system.”

What the work does not address is why L-amino acids and L-proteins emerged dominant on Earth. It is know that some meteorites have an excess of L-amino acids. “If one assumes that many primordial amino acids were seeded by meteorites, many of them have an excess of L over D amino acids,” Skolnick says. “All it would take is just a little bias to get the whole process started.”

Skolnick says the next step is to test the computer simulations by studying the emergent chemistry of nonchiral proteins.  A key unanswered question is how did replication emerge? “We can explain life’s biochemistry and many of the parts associated with replication from this study, but not replication itself,” he says. “If we can do this, then we have all of life’s components. If this works, ultimately I want to recreate what could be the early living systems in a test tube.” 

Here is the Nov. 5 story from the Cobb County Courier: Georgia Tech Professor Lewis Wheaton Wins Smyrna Ward 7 Council Seat

Lewis Wheaton, associate professor in the School of Biological Sciences, won a council seat in Smyrna Ward 7 after the Nov. 5 elections. He ran on supporting local schools, limiting density, and attracting retail businesses.

In Georgia Tech, Wheaton strives to improve the lives of upper-limb amputees through a deeper understanding of the relationship between the neurophysiology of motor learning and prosthesis adaptation. Since joining Georgia Tech in 2008, he has been directing the Cognitive Motor Control Lab, which aims to understand the neurophysiological processes associated with motor control of the upper limbs.

Wheaton has been leveraging his scientific expertise into community service. In Georgia Tech, he is co-director of Georgia Tech’s working group on Race and Racism in Contemporary Biomedicine.

In the state of Georgia, Wheaton is a Governor-appointed member of the State Rehabilitation Council. Mandated by the U.S. Congress, this council oversees the Georgia Vocational Rehabilitation Agency. In this capacity, Wheaton helps shape rehabilitation policy and management in the state of Georgia.

Wheaton will serve for four years, from Jan. 1, 2020, through Dec. 31, 2023. Meanwhile he will also serve the remaining term of his predecessor, who retired before the election, leaving the seat open.

In the accompanying video clip, Wheaton reflects on his election as follows:

You know, it's remarkable when you think of civic engagement and civic leadership and being a scientist, there are a lot of similarities. It's about being thoughtful. It's about having very clear purpose, having expectations, having goals, and even honestly, having hypotheses, right?

If you think about planning a particular community or thinking about planning a particular road in an area, you have to have an expectation that that road is actually going to be beneficial that’ll actually fit in. It's the same mindset that you do in science, right. You have a project; you have a thought; you think of how this could work, and you, based on those hypotheses, you execute.

Probably the biggest difference is that typically in city management those things are hard things; there are actually structures and things. In science, it doesn't always have to be a hard thing, so that'll be part of the fun.

But really, it's the same concepts. It’s the same ideas, and it's the same very thoughtful approach and really having an innovative approach that guides all of this.

First-year biology major Nabojeet Das has won quiz 8 of ScienceMatters Season 3.

Nabojeet is a first-year biology major from Tucker, Georgia. He says he chose to attend Georgia Tech because "it was closest to home and my cute Shih-Tzu, Zoey," shown with Nabojeet at right. 

Although not yet engaged in research, Nabojeet currently has a federal work-study job as a student assistant in the Histology Core Lab of the Parker H. Petit Institue of Bioengineering and Bioscience. Outside of academics, Nabojeet enjoys spending time with friends and politics. He is a member of the Young Democratic Socialists of America at Georgia Tech and serves as an ambassador for the Explore LLC (Living Learning Community).

Nabojeet usually listens to ScienceMatters when working alone or during his commute. "I love the podcast," he says. "It blows my mind thinking about the global impact of professors – with whom I will eventually take classes –  have made."

In addition, Nabojeet notes that ScienceMatters episodes are "not very long, which makes it super easy to fit into my schedule."  

The quiz question for episode 8 was: What nutrient is pulled out of the air by plants thanks to microbes?

The correct answer is nitrogen. 

Join the Quiz for Episode 9

Episode 9 features James "JC" Gumbart, an associate professor in the School of Physics, and his use of molecular dynamics simulations to chart the possible paths of molecules like proteins in hopes of finding solutions to problems like antibiotic-resistant bacteria.

Here’s the quiz question for episode 9:

What is the term for abnormal protein buildups in the brain?

Submit answer by 5 PM on Monday, Nov 18.

Periodic table t-shirts, must-have beaker mugs, and textured posters perfect for dorm rooms are among the prizes offered to those who are picked at random from all submitting correct answers. Look for the challenge during each week’s new episode, dropping on Tuesdays from Sept. 17 to Nov. 19.

Editor's Note: This story by Victor Rogers was published first on Nov. 20, 2019, in the Georgia Tech News Center. It was slightly modified for the College of Sciences website.

Fall is yellow jacket season. Not football or basketball, but the time of year when colonies of yellow jackets — the insects — reach their maximum size. It’s also when Professor Michael Goodisman and the Goodisman Research Group collect their nests.

“We typically collect nests for a month or so beginning in late October, which is prime time for collecting. The colonies usually die off around Thanksgiving, and are completely dead by Christmas — although climate change may be moving the dates,” said Goodisman, associate professor and associate chair for Undergraduate Education in the School of Biological Sciences.

Humans usually cross paths with the yellow jackets’ underground nests a couple of times a year. The first is between April and June, when people tend to mow their lawns frequently. The second is fall, when it’s time to rake leaves.

“Yellow jackets are particularly aggressive this time of year,” said Goodisman, whose team collects the insects alive, albeit somewhat sedated. The underground nests typically have a single hole, about the size of a silver dollar, for entering and exiting.

“We pour a little bit of anesthetic into the hole. It does the same thing to them that it does to us — it knocks them out,” Goodisman said. “Then we try to dig up the nest very quickly before they come to. We pull the nest out and bring it back to the lab.”

When collecting nests, Goodisman and the team wear beekeepers’ uniforms with long pants underneath for additional protection. Yellow jackets are aggressive and will push their way through air holes in the pith helmets, so the researchers cover them with tape to keep the insects out.

“I have had that happen to me, and it’s no fun at all!” said Goodisman. “If there’s an opening, they will find it and get in.”

Studying Yellow Jacket Behavior

The Goodisman Research Group is studying yellow jackets to learn about highly social behavior.

“Yellow jackets are an example of some of the most extreme and impressive social behavior that you will see in any animal, even more so than in humans,” Goodisman said. “Their social structure is similar to honeybees in that they typically have a single queen, though not always. She produces a bunch of selfless workers that work until the colony succeeds.”

The researchers are also interested in studying multiyear super colonies. Nests usually last only one season, from May to December. But when temperatures are mild, a colony can survive the winter and become massive the next year.

“We have seen this in New Zealand, Australia, and South Africa. We’re starting to see it in Florida, South Alabama, and California — super colonies the size of a car,” Goodisman said.

These changes bring up other questions, such as, are yellow jackets facing the same environmental threats as honeybees?

“The short answer is we don’t know. There’s no one studying yellow jackets the same way they’re studying honeybees,” Goodisman said. “But not all of the things that affect honeybees will affect yellow jackets.”

Honeybees have been partially domesticated and bred for successful pollination, reduced aggression, and increased honey production. Unfortunately, domestication often has unwanted side effects. For example, domesticated honeybees may display fewer behavioral defenses against parasites than feral honeybees as a consequence of the domestication process.

“Yellow jackets don’t really have that. We don’t associate yellow jackets with having a lot of diseases. They still could be subjected to pesticides, but it’s not really known,” Goodisman said.

It’s hard to tell if there has been a decrease in the yellow jacket population based on the calls the Goodisman Research Group receives.

“There has been no systematic survey that I know of,” he said. “I think a widespread survey over many years would be interesting.”

Go (Yellow) Jackets!

Goodisman’s interest in insects began when he was a child in Syracuse, New York.

“There are yellow jackets in Syracuse and all across North America, from Mexico to Alaska,” he said — indeed, they can be found all across the northern hemisphere. They are one of the most common and successful social insects.

“They’re great fun, as you might imagine. They have a lot of personality,” he said. “It’s exhilarating when you’re trying to pull them out of the ground or get them out of the house.”

His undergraduate research at Cornell University included work with insects, and he did his doctoral thesis at the University of Georgia on fire ants.

While at UGA he saw fire ants in a tray in the lab, and he thought it was “so cool.” But his work with yellow jackets didn’t start until he did postdoctoral work in Australia.

“There was some interesting research being done on invasive yellow jackets in Australia and New Zealand. I’ve been working on yellow jackets well before I came to Georgia Tech.”

It was purely coincidental that Goodisman became a professor at Georgia Tech, home of the Yellow Jackets. But it still causes the occasional raised eyebrow when he tells people about his research.

“People do a double take and ask if I’m at Tech because of my yellow jacket research. They ask if I have a yellow jacket professorship, or if I’m the ‘Chair of Yellow Jacket Research.’ It’s always a fun conversation, especially with Georgia Tech alumni.”

NOTE: Free yellow jacket nest removal. Nests will be used for research in the School of Biological Sciences. E-mail michael.goodisman@biology.gatech.edu to arrange a pickup.