Raquel L. Lieberman is the recipient of the 2017 Georgia Tech Sigma Xi Best Faculty Paper Award. Lieberman is an associate professor in the School of Chemistry and Biochemistry. The paper recognized by this award is “Enzymatic hydrolysis by transition-metal-dependent nucleophilic aromatic substitution,” published in Nature Chemical Biology.
The work involves protein crystallography, enzymology, and organic chemistry to address a question related to chemical ecology. This diversity of fields exemplifies the highly interdisciplinary questions Georgia Tech researchers are aiming to answer.
Also notable is the diversity of Lieberman’s research team. It involved high school, undergraduate, and graduate students; a technician; and a postdoctoral fellow. Also with the team was a remarkable high school teacher whose teaching has been transformed by doing research in the Lieberman lab. The paper uniquely embodies Georgia Tech’s motto: Progress and Service.
The paper describes a precedent-setting metalloenzyme discovered in the context of the complex biochemical warfare waged in farm soils where potato is grown. In such soils, the bacterium Streptomyces scabies infects potato tubers and secretes compounds that induce the formation of scabs; among them is 5-nitroanthranilic acid (5NAA).
Also in the same soils is another bacterium, Bradhyrhizobium sp. This nonpathogenic microbe seems to defend itself and the potato plant from S. scabies by detoxifying 5NAA. Lieberman’s collaborator of more than five years, Jim C. Spain, in the School of Civil and Environmental Engineering, discovered the unusual metalloenzyme in this bacterium.
The enzyme – 5-nitroanthranilic acid aminohydrolase (5NAA-A) – performs unusual chemistry: hydrolysis of a nitroaromatic compound. Nitroaromatic compounds are notoriously toxic, challenging to synthesize, and difficult to degrade, but are found widely in synthetic dyes, explosives, and pesticides.
The Lieberman team solved the structure of 5NAA-A and investigated its enzyme mechanism, substrate specificity, metal-binding properties, and phylogeny. They found that the chemistry it mediates, and the mechanism it uses, is rare among known enzymes.
A major force in the work was Casey Bethel, who is Georgia’s 2017 Teacher of the Year (TOTY). Bethel helped pave the way to solving the crystal structures of 5-NAA-A and mentored students who helped confirm its unique chemical properties.
A highly charismatic high school teacher, Bethel has spent the past six summers working in the Lieberman lab. His participation was made possible by Georgia Intern Fellowships for Teachers (GIFT), a program administered by the Center for Education Integrating Science, Mathematics, and Computing. Funds from Lieberman’s NSF CAREER award sponsored Bethel for four of the six years.
“It’s rare – we believe unprecedented! – in Georgia for the TOTY award to go to a STEM teacher at the high school level,” Lieberman says.
“On behalf of my co-authors, I thank Sigma Xi and Georgia Tech for this honor,” Lieberman says. “Not only does our discovery have impact from a number of scientific angles; our study also truly epitomizes the interdisciplinary and collaborative culture at Georgia Tech."
What can microorganisms teach us about climate change?
Plenty, because microbes respond, adapt, and evolve faster than other organisms. Scientists can discover how microorganisms will change because of global warming more quickly than is possible for complex organisms. Understanding how microbes respond to climate change will help predict its effects on other forms of life, including humans.
Yet our understanding of microbes’ complex functions in ecosystems and their interaction with a warming planet is incomplete. Filling the knowledge gaps is crucial, says a report just released by the American Academy of Microbiology and the American Geophysical Union. The report, based on a workshop of experts, underscores the importance of microbes in ecosystems buffeted by climate change and identifies priorities for future study.
In addressing climate change, it’s important to understand the importance of microbes in ecosystems, says Joel E. Kostka, a professor in the School of Biological Sciences and the School of Earth and Atmospheric Sciences. He was invited to the workshop for his expertise on microbes in terrestrial polar environments. Despite their size, microorganisms provide critical services to ecosystems, Kostka says. “Through activities that produce or consume greenhouse gases, microbes intimately impact Earth’s climate.”
Microbes are the decomposers, breaking down organic matter and recycling nutrients, Kostka says. “Literally, the clean air we breathe and the food we eat depend upon carbon and nutrient cycling – ecosystem services provided by microbes.”
However, the processes microbes mediate are complex and need to be better understood, Kostka says, “so we can make accurate predictions of how ecosystems will respond to climate change.”
One example of that complexity is plant-microbe interactions. Thousands of microbial species make up plant microbiomes – microbes that live inside or on plants. Microbiomes help plants grow better through nutrient acquisition among many functions. Conversely, microbes process organic matter produced by plants. How microbial communities will change due to Earth’s warming will depend on how plants respond and vice versa, Kostka says. To understand the effect of climate change on ecosystems, we have to know how plants and microbiomes interact or communicate.
Also highlighted by the workshop, Kostka says, is the need for communication across scientific disciplines. “I found myself informing the chemists on the latest information we have on microbes and microbial activity in wetlands, for example.”
The report is intended for the public, educators, and the broader science community, Kostka says. “I would hope that it represents a call to action for better understanding of microbiomes in the environment.”
Somebody give David Hu's graduate and undergraduate students medals for bravery -- and maybe some hazmat suits. Hu, an associate professor in the School of Biological Sciences and an adjunct associate professor in the School of Physics, is a 2015 Ig Nobel Prize winner for his "urination duration" research, and he and his intrepid fluid dynamics team have also gotten hands-on (yuck) with frog saliva. Now he has studied the physics of poop among mammals, venturing to Zoo Atlanta to follow elephants around and figure out things like speed, duration, size, mucosity, etc. Hu, also an associate professor in the George W. Woodruff School of Mechanical Engineering, makes the connection between his research and a better understanding of gastrointestinal health. The research also helped his team design state-of-the-art undergarments for astronauts. Hu's study was published April 25 in the journal (wait for it)....Soft Matter.
Everyone poops, and it takes them about the same amount of time. A new study of the hydrodynamics of defecation finds that all mammals take 12 seconds on average to relieve themselves, no matter how large or small the animal. The research, published in Soft Matter, reveals that the soft matter coming out of the hind ends of elephants, pandas, warthogs and dogs slides out of the rectum on a layer of mucus that keeps toilet time to a minimum. “The smell of body waste attracts predators, which is dangerous for animals. If they stay longer doing their thing, they’re exposing themselves and risking being discovered,” says Patricia Yang, a mechanical engineer at the Georgia Institute of Technology in Atlanta. Yang, a doctoral student in the Woodruff School of Mechanical Engineering, worked on the study with David Hu, associate professor in the School of Biological Sciences and an adjunct associate professor in the School of Physics.
Why was School of Biological Sciences associate professor David Hu drawn towards mammal poop as the topic of a new study? His experience as a working dad, he recently posted on the Conversation blog, "turned me from a poo-analysis novice to a wizened connoisseur." The people running the PBS Newshour website had a chance to digest the post and decided to share it in full on their Rundown blog. Hu is also a adjunct associate professor in the School of Physics and an associate professor in the George W. Woodruff School of Mechanical Engineering. Patricia Yang, a Ph.D. student in the Woodruff School of Mechanical Engineering, co-authored the study, which appeared in Soft Matter.
A research team led by Thomas J. DiChristina, a professor in the School of Biological Sciences, has figured out an easier, more environmentally-friendly way to break down lignocellulose (plant-based biomass) waste into bioproducts. The new approach? The use of microbes, instead of specialized enzymes, to power a Fenton reaction, a chemical process often used as a wastewater treatment. Hyun-Dong Shin, a research scientist in the School of Biological Sciences, co-authored the study, which was originally published in Biosource Technology.
It's Vice's turn to have fun with a new study on mammal defecation provided by School of Biological Sciences associate professor David L. Hu's lab. The study found that despite a wide range of sizes in bodies and feces, most healthy mammals poop at the same rate. There is one telling behind-the-scenes detail: study co-author Patricia Yang says her team promised other graduate students sharing the lab not to bring their animal dropping samples from the Atlanta Zoo into the lab until after 5 p.m. because of the smell. Hu is also an adjunct associate professor in the School of Physics and an associate professor in the George W. Woodruff School of Mechanical Engineering. Yang is a Ph.D. student in the Woodruff School of Mechanical Engineering.
Athletics brought Madison R. Young to Georgia Tech, and that would have been enough to allow her to shine. “A strong member of the diving squad for the Jackets,” crows the Ramblin' Wreck sports website as it lists her accomplishments in ACC and NCAA diving competitions. But she can balance athletic ability and academic achievements: She was named Scholar Athlete of the Year as a senior at Crean Lutheran High School in Irvine, Calif., and was on the ACC Academic Honor Roll. Now she’s celebrating a Bachelor of Science degree in Biology/Pre-Health with Business/Research options.
What attracted you to Georgia Tech?
I am an athlete, and I was recruited to attend Georgia Tech. But I was already attracted to Tech because of its very strong academics and good reputation around the country and the world.
How would you describe your life before enrolling in Georgia Tech?
I was much less open-minded.
What is the most important thing you learned at Georgia Tech?
The most important thing I learned at Tech is that hard work does actually pay off, and collaboration is very important both now and later. I also learned that Tech teaches you to actually think, not just complete assignments. I know this will help me later on when I am presented with issues in my job that require not only knowledge of the issue but critical thinking.
What surprised or disappointed you the most about Georgia Tech?
I was disappointed during my freshman year when I got poor grades on all of my first exams. I was most surprised by how much all of my professors have cared about my individual, academic, and athletic success.
Which professor(s) or class(es) made a big impact on you?
Jeannette Yen and Bill Todd have had the biggest impact on me. They taught me how to work in professional situations and how to use what I have learned at Tech in the workplace. I did research with Dr. Yen for two and a half years and she helped me write an undergraduate thesis on behavioral ecology, something I had never expected I would be able to do. Under Professor Todd I completed a work study program with Children’s Healthcare of Atlanta and learned how to act as a consultant, a skill that I will carry with me forever.
What is your most vivid memory of Georgia Tech?
My participation in athletics is my most vivid memory of Tech. I formed unbelievable friendships with my teammates and cannot imagine going through four years at Georgia Tech without them.
If you participated in experiential learning activities, what was the most valuable outcome from your experience?
I participated in undergraduate research in behavioral ecology with Jeannette Yen. I was able to complete the research option and write a thesis under her supervision. The most valuable outcome of my experience was the confidence I gained to complete a project on my own, including running and designing the experiments, analyzing the data, and writing my thesis. It also taught me problem solving and perseverance.
On the basis of your experience, what advice would you give to incoming freshmen at Georgia Tech?
Time management is the key to success. Start studying way before you think you need to, and never pull an all-nighter!
What feedback would you give to Georgia Tech to improve the campus experience for future students?
I think the GT 1000 class needs to have better structure. I honestly did not learn much through GT 1000. My class was focused on the history of Tech, which was fun to learn, but I think it should show students more resources in case they need help. It should also provide more assistance on time management and study techniques.
Where are you headed after graduation?
I am heading to Auburn University Veterinary School to pursue a DVM. I wish to work with horses and eventually be an equine surgeon. Tech has prepared me by giving me a strong science foundation, which I believe will be much greater than that of my graduate-school peers.
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Scientific American has reprinted David Hu and Patricia Yang's April 26 article from The Conversation detailing their new research on the defecation habits of mammals. (The Conversation also lists that article as one of its most read items for the past week). In addition to being an associate professor in the School of Biological Sciences, Hu is also an adjunct associate professor in the School of Physics and an associate professor in the George W. Woodruff School of Mechanical Engineering. Yang is a Ph.D. student in the Woodruff School of Mechanical Engineering.
Science News is the latest stop for media coverage of David Hu and Patricia Yang's poop paper. This story contains details on how much work the researchers had to do to get information on mammal defecation, including trips to Zoo Atlanta to gather feces, and studying YouTube videos of animals pooping (are you really that surprised such videos exist?) Hu is an associate professor in the School of Biological Sciences, an adjunct associate professor in the School of Physics and an associate professor in the George W. Woodruff School of Mechanical Engineering. Yang is a Ph.D. student in the Woodruff School of Mechanical Engineering.