Georgia Tech's Samuel Kelly is the winner of the ScienceMatters Episode 10 quiz. Kelly is a research technician in the School of Biological Sciences.
Episode 10, "Chasing Cancer with Gold," stars Mostafa El-Sayed, a professor in the School of Chemistry and Biochemistry.
"I am a new listener to ScienceMatters," Kelly says. "The way I found it was the interview of Dr. Mostafa El-Sayed."
Kelly is Georgia Tech graduate with a B.S. in Chemistry. He remembers El-Sayed as a great professor in the School of Chemistry and Biochemistry. El-Sayed's research in nanoscience was, when Kelly was an undergrad, new for the school, he says, "I have followed his work through the years."
The Episode 10 quiz question: What is the name of Mostafa El-Sayed's son who is also his collaborator in cancer research?
The answer: Ivan
Episode 10 concludes Season 1 of ScienceMatters. Stay tuned for Season 2, coming in January 2019.
Editor's Note: This story by Ben Brumfield was first published on Research Horizons on Oct 23, 2018. The title was revised for the College of Sciences website.
Sea creatures living in captivity need to go to the bathroom, too. That means aquarium water must be cleaned of waste like ammonia, nitrites, and nitrates. Good bacteria break down nitrogen compounds at Georgia Aquarium, and in a new study, some bacterial communities there emulated those found naturally in oceans surprisingly well.
“I didn’t expect this,” said Frank Stewart, a professor in the School of Biological Sciences and principal investigator of a study led by the Georgia Institute of Technology. “The microbial communities are seeded from microbes coming from the animals and their food in an aquarium that does not tap into the ocean. But these looked like natural marine microbial communities.”
That’s happy news for the thousands of sea fauna, including whale sharks, manta rays and a sea turtle named “Tank,” who live in Georgia Aquarium’s Ocean Voyager, the largest indoor oceanic exhibit in the United States with nearly 24 million liters (6.3 million gallons) of constituted sea water. The researchers analyzed two bacterial communities in the exhibit over time and studied their water cleaning abilities.
‘Real game changer’
“The bacterial analysis has been a real game changer for Georgia Aquarium,” said Eric Hall, who collaborated on the research and is Senior Director for Life Support Systems and Water Quality for the aquarium. “We now have a much better understanding of what this beneficial bacterial micro-community looks like that is living in the habitat water and in our filters.”
The researchers would like their continuing work to help aquarium operators everywhere optimize bacterial colonies for maximum water cleansing. Georgia Tech and Georgia Aquarium, a non-profit sea life organization, published their analysis in the journal Applied and Environmental Microbiology on Friday, September, 29, 2018, and Georgia Aquarium share the results with other aquariums and universities near them.
First author was Andrew Burns, a postdoctoral researcher in Stewart’s lab. The research was funded by the Simons Foundation, the National Science Foundation, and the Teasley Endowment.
Fish poo be gone
To stay fresh, Ocean Voyager’s water cascades through a series of cleaning processes. In the tank, as in oceans, bacteria break down excrement, ammonia and other waste, then the aquarium exhibit’s water flows through filters that remove more things, including nitrites.
The water also flows through special bacterial reactors, and by then it’s free from most everything but nitrates, which can become toxic if allowed to build up to high concentrations. In the reactors, colonies of bacteria, the focus of this study, break nitrates down.
The reactors, or “pads,” have nearly no oxygen and offer bacteria sulfur as food. So, anaerobic bacteria gather there to “eat” the sulfur and “breathe up” the nitrates to form nitrogen gas, which can bubble up to the atmosphere. Earth’s atmosphere is naturally about 78 percent nitrogen.
Motley bacterial surprise
The bacterial communities the researchers encountered in the two pads they studied dashed expectations. For one, the researchers thought they might find both pads dominated by an iconic denitrifying bacterium called Thiobacillus denitrificans, which can be used to hand-seed professional and home aquariums. They did not.
“It certainly popped up in our systems, but the genes for the tools that Thiobacillus denitrificans carries to do these processes were widely distributed among many different kinds of microbes,” said Stewart, who is an associate professor in Georgia Tech’s School of Biological Sciences. “The diversity levels were just outstanding.”
Also, the compositions of bacterial communities in the two pads were virtually each other’s polar opposites.
“In one of the pads we had one species become around 90 percent of the community,” Burns said. It was a strain related to a species called Thiobacillus thioparus. “The other pad had a much more diverse community with a lot of different species and even genera.” (Genus is the taxonomic category above species.)
“Even looking at some of the main contributors, there was one genus of Sulfurimonas(bacteria) and even those had a ton of different species, about 150 species or strain variants instead of say, ten, which one might have expected,” Stewart said.
Bacterial NFL draft
Like sports teams, the two bacterial communities assembled different players. One team had one big star player, and the other team spread the skills needed for all the chemical steps across the squad.
“We found that in a lot of these systems a single bacterium is going to become the main contributor, and that it will outcompete everybody else and become the majority of the community and do most of the metabolism,” Burns said. “In our study, this pad turned out to be better at denitrification.”
But it could work the other way around, that particular mixed bacterial communities may work more efficiently, Burns said, and even in systems where one player is the star, variety can add strength.
“It can give that bacterial system a backup,” Burns said. “If it relied on only one big player, if something happened to it, the whole system could crash.”
“What is really interesting is how many of a certain species exists in our system and especially finding out what they are doing,” Hall said. “These microscopic creatures are not just hanging around but actually doing beneficial things for our water that we didn’t understand this thoroughly before.”
It’s too early to make recommendations, but given the initial observations, the researchers think that anyone trying to optimize bacteria for the aquarium may not necessarily have to throw one great organism into a system from the outside. Coaxing a great bacterial community to self-assemble instead might maximize cleaning power.
GA aquatic rescuers
The Ocean Voyager gallery was built by Home Depot and is one of the largest aquatic exhibits in the world, according to Georgia Aquarium. The exhibit was specially designed to house whale sharks, the largest fish species in the world and also an endangered species conservationist are working to preserve.
Georgia Aquarium could possibly have the most aquatic life of any aquarium complex, but that is only part of the non-profit organization’s activities. For example, its animal rescuers save stranded sea lions, and threatened otters and sea turtles.
Georgia Aquarium researchers explore the underwater world to expand knowledge needed to protect sea life and habitats, including imperiled coral reefs. And they improve animal care methods to help save and breed endangered species.
Read about more of Frank Stewart’s research: Global Warming, a Dead Zone, and Mysterious Bacteria
The following authors contributed to this study: Cory Padilla and Zoe Pratte of Georgia Tech; Kailen Gilde, Matthew Regensburger and Eric Hall of Georgia Aquarium and Alistair Dove of Georgia Tech and Georgia Aquarium. This work was funded by the Simons Foundation (award 346253), the National Science Foundation Advances in Bioinformatics Program (award 1564559), the NSF Biological oceanography program (award 1151698), and the Teasley Endowment. Any findings, opinions, conclusions or recommendations herein are those of the authors and not necessarily of the funding agency/agencies.
Georgia Tech's Elisabetta "Sabetta" Matsumoto is the winner of the ScienceMatters Episode 9 quiz. An assistant professor in the School pf Physics, Matsumoto is our first winner from among the Georgia Tech faculty.
Matsumoto walks to work and back, and she enjoys running in Piedmont Park. "That's usually when I listen to podcasts," she says. She says she has listened to about six episodes of ScienceMatters. "I really enjoy getting to see work of my friends and colleagues getting publicized."
Matsumoto joined Georgia Tech in 2016. Her research centers around the relationship between geometry and material properties in soft systems, including liquid crystals, 3D printing, and textiles. She uses techniques from differential geometry and geometric topology to develop a mathematical underpinning for these materials. She is also interested in using knitting, sewing, 3D printing, and virtual reality in mathematical art and education.
The Episode 9 quiz question: What group of people can’t tell the difference between a coffee cup and a donut?
The answer: topologists.
Episode 10 of ScienceMatters is out this week. "Chasing Cancer with Gold" stars Mostafa El-Sayed, professor in the School of Chemistry and Biochemistry.
If you would like to join the ScienceMatters Hall of Fame, enter the answer to this question: What is the name of Mostafa El Sayed’s son who is also his collaborator in cancer research?
Submit your answer by 11 a.m. Monday, October 29, at sciencematters.gatech.edu..
Georgia Tech mathematician Lew Lefton explained the odds of winning the $1.6 billion Mega Millions jackpot. The drawing on Tuesday, Oct. 23, turned up a winning ticket sold in South Carolina. But as Lefton said many times in many venues, it won't be you.
Lefton's first appeared on Georgia Tech YouTube and then at the Atlanta Journal Constitution's coverage.Those were followed by guest spots on Canadian TV and BBC World Service.
A new study demonstrates the physics that elephants use to feed themselves the massive quantities of leaves, fruit and roots needed to sustain their multi-ton bodies.
A human can pick up multiple objects at once by squeezing them together with both hands and arms. An African elephant also picks up many items at once but with only one appendage—its soft, heavy trunk. How the elephant solves this challenge could provide inspiration for future robotics.
A wild African elephant eats rapidly, consuming 190 grams of food a minute, to provide adequate fuel for its vast bulk. “Elephants are in a rush when they are eating,” said David L. Hu, associate professor in the School of Mechanical Engineering and the School of Biology at the Georgia Institute of Technology. The elephant diet consists of large volumes of plant materials such as leaves, fruit and roots. To eat these, elephants sweep loose items into a pile and crush them into a manageable solid that can be picked up by the trunk.
“They don’t just use the trunk’s strong muscles to squeeze the plants together,” said Hu. “The elephants also use the weight of the trunk, and they do that by forming a joint in the trunk. The trunk below the joint becomes a stiff pillar that applies weight to the pile of plant materials.”
About 30 percent of the applied force is derived from the pillar’s weight alone, and about 70 percent from exerting muscular effort, according to a new study published in the Journal of the Royal Society Interface by Hu and colleagues at Georgia Tech, the Rochester Institute of Technology and Zoo Atlanta.
The African elephant can raise or lower the trunk joint’s height by up to 11 centimeters to increase or reduce the applied force. “When elephants need more force, the joint is higher up on the trunk,” Hu said. Elephant trunks weigh about 150 kilograms and have 40,000 muscles. “The huge number of muscles in the trunk allows the elephant great freedom for where it puts this joint.”
Hu and his colleagues studied a 34-year-old female African elephant (Loxodonta africana) over several weeks in the summer of 2017. All experiments were supervised by the staff at Zoo Atlanta. Food was arranged by hand into a pile in the center of a force plate to measure how much force the animal generated.
The elephant’s trunk is similar to other boneless organs in nature such as the octopus’s arm and the human tongue. But unlike an octopus’s arm, an elephant’s trunk is heavy enough to provide significant force on an object without muscular pressure. This is the first study to show that an animal can use the weight of its own appendage to help apply force and the first with a live elephant to understand forces that it can apply to materials.
Using mathematical models, the researchers found that the greater the number of objects to be squeezed and picked up, the greater the force that must be applied.
“Picking up two objects requires very little force to press them together, while picking up 40,000 objects requires a lot of force,” Hu said. This principle was tested experimentally with the live elephant by presenting multiple food items varying in number from four to 40,000 in number. The experiments showed that the elephant could vary forces applied with its trunk by a factor of four depending on the number of food items to be picked up.
This research could have applications in robotics, where heavier machines would appear to have few advantages over smaller ones. But, in the future, heavy robotic manipulators could be designed with several adjustable joints that use the device’s own weight to provide adjustable pressure and save energy. There are currently no commercial robots designed to apply their own weight to objects, Hu noted.
“You could have future robots with several joints, which could apply various weight pressures below joints to help compress objects together for lifting them efficiently,” said Hu. “This would allow you to use the weight of the joints themselves to provide force instead of relying on batteries and extra motors to apply these forces, and that would mean using less energy. For instance, you could have a heavy robot with four joints, and by bending the top joint, the weight below it could apply a load. If you wanted to provide less weight pressure, you could instead bend the second-from-the-top joint. This study shows that there are some advantages for robots in being big and heavy.”
African elephants like the ones in this study have two muscular extensions at the tip of their trunk resembling a pair of fingers that also could be studied as models for future robotics. It’s not well known that elephants have such projections, and this understanding could inform work that is already underway. “The elephant’s technique with these extensions might be used to develop soft robotic grippers that can pick up delicate items such as fruit without damaging them,” Hu noted.
This work was supported by the U.S. Army Research Laboratory and the U.S. Army Research Office Mechanical Sciences Division, Complex Dynamics and Systems Program, under contract W911NF-12-R-0011.
CITATION: Jianing Wu, et al., “Elephant trunks form joints to squeeze together small objects,” (Journal of the Royal Society Interface 15, 2018) http://dx.doi.org/10.1098/rsif.2018.0377
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How do Elephants Eat With Their Trunks?
By Roni Dengler | October 23, 2018 6:01 pm
As the largest land mammal on the planet, elephants eat a lot of food. On average, the giants consume more than 440 pounds of vegetation per day, or the equivalent of about two corncobs per minute. And now, scientists have figured out how the beasts are able to eat so much so fast....To figure out how elephants pick up so much stuff at a time, David Hu and his colleagues filmed a 34-year-old female African elephant from the Atlanta zoo as she consumed loads of carrots and rutabagas cut into differently sized cubes, as well as heaps of bran.
Read the full story by Roni Dengler here.
David Hu is an associate professor in the Schools of Mechanical Engineering and Biological Sciences and an adjunct associate professor in the School of Physics.
David Hu's investigation of elephant tails is receiving wide coverage in outside media.
According to Nature's "Why an elephant's tail is a feeble fly-swatter," the tail is a non-lethal weapon against pests. Read the full Nature story here.
David Hu is an associate professor in the School of Biological Sciences and an adjunct associate professor in the School of Physics.
Science republishes a story by Scott Waldman of E&E News, detailing the make-up of the finalists for membership in the Environmental Protection Agency's Science Advisory Board. Many finalists are climate change deniers. Exceptions are academics whose work has been funded by premier U.S. science agencies. Among them is Georgia Tech's Kim Cobb, a professor in the School of Earth and Atmospheric Sciences.
Episode 9 of ScienceMatters' Season 1 stars Mostafa El-Sayed. Listen to the podcast, read the transcript, or download the episode from here.
Mostafa El-Sayed is the Regents Professor and Julius Brown Chair in the School of Chemistry and Biochemistry.
El-Sayed's current research interests encompass nanoscience and the potential applications of nanoparticles in various applications including medicine and catalysis. His research group is housed in the Laser Dynamics Laboratory (LDL). LDL houses the most recent lasers and laser spectroscopic equipment for time-resolved studies in the femto-to-millisecond time scale.
In Episode 10, El-Sayed describes how seeing his wife suffer from cancer got him involved in exploring nanoparticles as a potential cancer treatment.
Take a listen at sciencematters.gatech.edu.
Enter to win a prize by answering the question for Episode 10:
What is the name of Mostafa El-Sayed’s son who is also his collaborator in cancer research?
Submit your entry by 11 AM on Monday, Oct. 29, at sciencematters.gatech.edu.
Georgia Tech alumna Megen Wittling is the winner of the ScienceMatters Episode 8 quiz. She is our first winner from outside the Georgia Tech campus. Having graduated last May, she now works in the Food & Drug Administration (FDA), Washington, DC. Her ScienceMatters prize is in the mail!
"I listen to ScienceMatters on my commute to work while I ride the Metro," Wittling says."I have listened to four episode so far, and love it!"
Wittling hails from Johns Creek, Georgia. She graduated with a B.S. degree in Biology, with a minor in Health and Medical Sciences. After graduation, she went for an ORISE Research Fellowship at FDA, while she applies to MD and MD/PhD programs.
As an undergrad, Wittling conducted research in the PARK Lab of the School of Psychology under the guidance of Phillip Ackerman. The lab's research spans cognitive, aging, personality, social, and applied psychology domains.
From there, Wittling moved to the lab of Shuyi Nie, an assistant professor in the School of Biological Sciences and a member of the Parker H. Petit Institute of Bioengineering and Bioscience. A Petit Undergraduate Research Scholar Award made the transfer possible. In the Nie lab, Wittling characterized the role of a protein in the development and migration of certain cells.
At FDA, Wittling works in the Laboratory of Immunobiochemistry, where she studies the response to interferon of bronchial epithelial cells.
The Episode 8 quiz question: What brain waves are associated with deep states of sleep?The answer: Delta waves.
Episode 9 of ScienceMatters is out this week. "The Mathematics of ... Donuts?" stars Dan Margalit, professor in the School of Mathematics.
If you would like to join the ScienceMatters Hall of Fame, enter the answer to this question: According to Episode 9, what group of people can’t tell the difference between a coffee cup and a donut?
Submit your answer by 11 a.m. Monday, October 22, at sciencematters.gatech.edu.
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