Duke Research Blog

Following the people and events that make up the research community at Duke.

Category: Biology Page 1 of 23

The evolution of a tumor

The results of evolution are often awe-inspiring — from the long neck of the giraffe to the majestic colors of a peacock — but evolution does not always create structures of function and beauty.

In the case of cancer, the growth of a population of malignant cells from a single cell reflects a process of evolution too, but with much more harrowing results.

Johannes Reiter uses mathematical models to understand the evolution of cancer

Researchers like Johannes Reiter, PhD, of Stanford University’s Translational Cancer Evolution Laboratory, are examining the path of cancer from a single sell to many metastatic tumors. By using this perspective and simple mathematical models, Reiter interrogates the current practices in cancer treatment. He spoke at Duke’s mathematical biology seminar on Jan. 17.

 The evolutionary process of cancer begins with a single cell. At each division, a cell acquires a few mutations to its genetic code, most of which are inconsequential. However, if the mutations occur in certain genes called driver genes, the cell lineage can follow a different path of rapid growth. If these mutations can survive, cells continue to divide at a rate faster than normal, and the result is a tumor.

As cells divide, they acquire mutations that can drive abnormal growth and form tumors. Tumors and their metastases can consist of diverse cell populations, complicating treatment plans out patient outcomes. Image courtesy of Reiter Lab

With each additional division, the cell continues to acquire mutations. The result is that a single tumor can consist of a variety of unique cell populations; this diversity is called intratumoral heterogeneity (ITH). As tumors metastasize, or spread to other locations throughout the body, the possibility for diversity grows.

Intratumoral heterogeneity can exist within primary tumors, within metastases, or between metastases. Vogelstein et al., Science, 2013

Reiter describes three flavors of ITH. Intra-primary heterogeneity describes the diversity of cell types within the initial tumor. Intrametastatic heterogeneity describes the diversity of cell types within a single metastasis. Finally, inter-metastatic heterogeneity describes diversity between metastases from the same primary tumor.

For Reiter, inter-metastatic heterogeneity presents a particularly compelling problem. If treatment plans are made based on biopsy of the primary tumor but the metastases differ from each other and from the primary tumor, the efficacy of treatment will be greatly limited.

With this in mind, Reiter developed a mathematical model to predict whether a cell sample collected by biopsy of just the primary tumor would provide adequate information for treatment.

Using genetic sequence data from patients who had at least two untreated metastases and a primary tumor, Reiter found that metastases and primary tumors overwhelmingly share a single driver gene. Reiter said this confirmed that a biopsy of the primary tumor should be sufficient to plan targeted therapies, because the risk of missing driver genes that are functional in the metastases proved to be negligible.

 In his next endeavors as a new member of the Canary Center for Cancer Early Detection, Reiter plans to use his knack for mathematical modeling to tackle problems of identifying cancer while still in its most treatable stage.  

Post by undergraduate blogger Sarah Haurin

Post by Sarah Haurin

Flu No More: The Search for a Universal Vaccine

Chances are, you’ve had the flu. 

Body aches, chills, congestion, and cough—for millions across the globe, these symptoms are all too familiar.

For some, though, the flu leads to serious complications. Last year, as many as 647,000 Americans were hospitalized due to flu-related illness, with an additional 61,000 deaths.

Countless hours of lost productivity also accompany the illness. Including hospitalization costs, estimates for the flu’s total economic burden range from 10 to 25 billion dollars each year.

Flu prevention efforts have yielded mixed results. For many viruses, vaccines provide protection that lasts a lifetime, building up a network of antibodies primed to neutralize future infections. Influenza viruses, however, mutate quickly, rendering vaccines from years past ineffective. As a result, new vaccines are constantly in development. 

Every year, researchers predict which flu viruses are likely to dominate the upcoming flu season. Based on these predictions, new vaccines target these specific strains. Consequentially, the effectiveness of these vaccines vary with the prediction. When a vaccine is a good match for the dominant flu strain, it can lower rates of infection by 40-50%. When it isn’t, its preventative power is far lower; in 2014, for example, the yearly influenza vaccine was only 19% effective

Peter Palese, Ph. D, might have a better solution. Working at the Icahn School of Medicine, Palese and his team are developing a vaccine that takes a new approach to flu prevention. 

Just before classes ended last month, Palese spoke at the Duke Influenza Symposium, a showcase of Duke’s current research on influenza. The symposium is part of Duke’s larger push to improve the efficacy of flu vaccination.

Palese’s vaccines work by redirecting the immune response to the influenza virus. Traditional vaccines create antibodies that target hemagglutinins, proteins found on the outermost part of influenza viruses. Hemagglutinins are divided into two regions: a head domain and a stalk domain (Fig. 1).

Fig. 1: Left: General influenza structure. Right: Hemagglutinins are divided into two regions: a head domain and a stalk. The head domain is prone to mutation and undergoes rapid change while the stalk domain is more resistant to mutation.
Source: Frontiers in Immunology

In a traditional vaccination, the head domain is immunodominant—that is, the antibodies produced by vaccines preferentially target and neutralize the head domains. However, the head domain is highly prone to mutation and varies between different strains of influenza. As a result, antibodies for one strain of the virus provide no protection against other strains.

The new vaccines pioneered by Palese and his team instead target the stalk domain, a part of hemagglutinin that mutates far slower than the head domain. The stalk is also conserved across different subtypes of the influenza virus. As a result, these vaccines should theoretically provide long-lasting protection against most strains of influenza.

Testing in ferret, mice, and guinea pigs have produced promising results. And early human trials suggest that this new kind of vaccination grants broad immunity against influenza. But long-term results remain unclear—and more trials are underway. “We would love to say it works,” Palese says. “But give us 10 years.”

In the meantime, the seasonal flu vaccine is our best option.“The recommendation to vaccinate everyone is the right policy,” Palese tells us.

Post by Jeremy Jacobs

Working Through Frustrations to Understand Nature Better

This is the fifth of six posts written by students at the North Carolina School of Science and Math as part of an elective about science communication with Dean Amy Sheck.

Research is a journey full of uncertainty in which scientists have to construct their own path, even if they’re unsure of what the end of the journey actually is. Despite this unpredictability, researchers continue their journey because they believe their work will one day drive their fields forward. At least, that’s why Kate Meyer Ph.D. says she has investigated something called m6A for several years.

Kathryn Meyer, Ph.D.

“Virtually every study that I have ever been part of had some frustrations involved because everything can fall apart in just one night,” Meyer said. “Despite all the frustrations you might have, you are still in the research because you know that at the end of the day, you will get new knowledge that is worthy to your field, or perhaps to the world.”

N6-methyladenosine (or m6A) is a modification to one of the four main bases of RNA – adenosine. Because RNA plays a significant role as a bridge between genetic information and functional gene products, modifications in RNA can alter how much of a certain product will be produced, which then controls how our cells and eventually our whole body functions.

The idea of this tiny but powerful modification was first proposed in the 1970s. But scientists struggled to find where m6A was located in the cell before research Meyer made a major contribution to as a trainee was published in 2012. Combining a newly developed antibody that could recognize m6A and gene sequencing techniques that became more accessible to the researchers, Meyer’s work led to the first method that can detect and sequence all of the m6A regions in a cell.

m6A’s interaction with a neuron, as depicted on Dr. Meyer’s laboratory site.

Meyer’s work was transformative research. Her method allowed laboratories around the world to investigate what regulates m6A and what its consequences are. Meyer said this first study which ignited m6A field is one of her most prideful moments as a researcher. 

Significant progress has been made since 2012, but there are still lots of questions that need to be answered. Currently, Meyer’s research team is investigating the relationships between m6A and various neurological issues. She believes that regulation of m6A controls the expression, or activity level, of various genes in the brain. As such, m6A may play an important role in neurodegenerative diseases and memory.

Author Jun Hee Shin, left, and Kate Meyer in her lab.

As an assistant professor of both biochemistry and neurobiology at Duke, Meyer is definitely one of the most important figures in the m6A field. Despite her many accomplishments, she said she had experienced and overcome many frustrations and failures on her way to the results.

Guest Post by Jun Shin, NCSSM 2020

How Do You Engineer a Microbial Community?

This is the first of several posts written by students at the North Carolina School of Science and Math as part of an elective about science communication with Dean Amy Sheck.

Claudia Gunsch, the Theodore Kennedy distinguished associate professor in the department of civil and environmental engineering, wants to know how to engineer a microbial community. An environmental engineer with a fascination for the world at the micro level, Gunsch takes a unique approach to solving the problem of environmental pollution: She looks to what’s already been done by nature.

Claudia Gunsch, Ph.D.

Gunsch and her team seek to harness the power of microbes to create living communities capable of degrading contamination in the environment.

“How can you engineer that microbial community so the organisms that degrade the pollutant become enriched?” she asks. “Or — if you’re thinking about dangerous pathogenic organisms — how do you engineer the microbial community so that those organisms become depressed in that particular environment?”

The first step, Gunsch says, is to figure out who’s there. What microbes make up a community? How do these organisms function? Who is doing what? Which organisms are interchangeable? Which prefer to live with one another, and which prefer not living with one another?

“Once we can really start building that kind of framework,” she says, “we can start engineering it for our particular purposes.”

Yet identifying the members of a microbial community is far more difficult than it may seem. Shallow databases coupled with vast variations in microbial communities leave Gunsch and her team with quite a challenge. Gunsch, however, remains optimistic.

Map of U.S. Superfund Sites (2013)

“The exciting part is that we have all these technologies where we can sequence all these samples,” she says. “As we become more sophisticated and more people do this type of research, we keep feeding all of this data into these databases. Then we will have more information and one day, we’ll be able to go out and take that sample and know exactly who’s there.”

“Right now, it’s in its infancy,” she says with a smile. “But in the long-term, I have no doubt we will get there.”

Gunsch is currently working on Duke’s Superfund Research Center designing bioremediation technologies for the degradation of polycyclic aromatic hydrocarbon (PAH) contamination. These pollutants are extremely difficult to break down due to their tendency to stick strongly onto soil and sediments. Gunsch and her team are searching for the right microbial community to break these compounds down — all by taking advantage of the innate capabilities of these microorganisms.

A photo montage from Dr. Gunsch’s lab page.

Step one, Gunsch says, has already been completed. She and her team have identified several different organisms capable of degrading PAHs. The next step, she explains, is assembling the microbial communities — taking these organisms and getting them to work together, sometimes even across kingdoms of life. Teamwork at the micro level.

The subsequent challenge, then, is figuring out how these organisms will survive and thrive in the environment they’re placed in, and which microbial seeds will best degrade the contamination when placed in the environment. This technique is known as “precision bioremediation” — similar to precision medicine, it involves finding the right solution in the right amounts to be the most effective in a certain scenario.

“In this particular case, we’re trying to figure out what the right cocktail of microbes we can add to an environment that will lead to the end result that is desired — in this case, PAH degradation,” Gunsch says.

Ultimately, the aim is to reduce pollution and restore ecological health to contaminated environments. A lofty goal, but one within sight. Yet Gunsch sees applications beyond work in the environment — all work dealing with microbes, she says, has the potential to be impacted by this research.

“If we understand how these organisms work together,” she says, “then we can advance our understanding of human health microbiomes as well.”

Post by Emily Yang, NCSSM 2021

A Research Tour of Duke’s Largest Lab

“Lightning is like a dangerous animal that wants to go places. And you can’t stop it,” smiled Steve Cummer, Ph.D. as he gestured to the colorful image on the widescreen TV he’d set up outside his research trailer in an open field in Duke Forest.

Cummer, the William H. Younger Professor of electrical and computer engineering at Duke, is accustomed to lecturing in front of the students he teaches or his peers at conferences. But on this day, he was showing spectacular videos of lightning to curious members of the public who were given exclusive access to his research site on Eubanks Road in Chapel Hill, about 8 miles west of campus.

Steve Cummer shows a time-lapse video of lightning to the visitors on the annual Duke Forest Research Tour in the Blackwood Division of the Duke Forest.

More than two dozen members of the community had signed up for a tour of research projects in the Blackwood Division of Duke Forest (which recently expanded), a research-only area that is not normally open to the public. Cummer’s research site was the last stop of the afternoon research tour. The tour also covered native trees, moths and geological features of the Blackwood Division with biologist and ecologist Steve Hall, and air quality monitoring and remote sensing studies with John Walker and Dave Williams, from the U.S. Environmental Protection Agency.

The Hardwood Tower in the Blackwood Division is used for air quality monitoring and remote sensing studies. Researchers frequently climb the 138 foot tall tower to sample the air above the tree canopy.

Cummer’s research on lightning and sprites (electrical discharges associated with lightning that occur above thunderstorm clouds) sparked a lively question and answer session about everything from hurricanes to how to survive if you’re caught in a lightning storm. (Contrary to popular belief, crouching where you are is probably not the safest solution, he said. A car is a great hiding spot as long as you don’t touch anything made of metal.)

Cummer kept his tone fun and casual, like a live science television host, perched on the steps of his research trailer, referring to some of the scientific equipment spread out across the field as “salad bowls,” “pizza pans” and “lunar landers,” given their odd shapes. But the research he talked about was serious. Lightning is big business because it can cause billions of dollars in damage and insurance claims every year.

An ash tree (Fraxinus spp.) being examined by one of the visitors on the Duke Forest Research tour. Blackwood Division ash trees are showing signs of the highly destructive emerald ash borer invasion.

Surprisingly little is known about lightning, not even how it is first formed. “There are a shocking number of things,” he said, pausing to let his pun sink in, “that we really don’t understand about how lightning works. Starting with the very beginning, nobody knows exactly how it starts. Like, really the physics of that.”  But Cummer loves his research and has made some advances in this field (like devising more precise sensor systems), “When you’re the first person to understand something and you haven’t written about it yet or told anyone about it… that’s the best feeling.”

The Duke Forest hosted 49 research projects last year, which —with less than half of the projects reporting—represented over a million dollars of investment in Duke Forest-based work. 

“The Duke Forest is more than just a place to walk and to jog. It’s an outdoor classroom. It’s a living laboratory. It’s where faculty and teachers and students of all ages come to learn and explore,” explained Sara Childs, Duke Forest director.

The Duke Forest offers their research tour every year. Members of the public can sign up for the email newsletter to be notified about future events.

Post by Véronique Koch

Stalking Elusive Ferns Down Under

Graduate student Karla Sosa (left) photographs and presses newly collected ferns for later analysis while Ashley Field (in truck) marks the GPS location of the find.

In Queensland, Australia, early March can be 96 degrees Fahrenheit. It’s summer in the Southern Hemisphere, but that’s still pretty hot.

Although hot, dry Australia probably isn’t the first place you’d think to look for ferns, that’s precisely why I’m here and the sole reason we’ve hit the road at 6 a.m. Our schedule for the day: to drive as far south as we can while still letting us come home at the end of the day.

My local colleague, Ashley Field, grew up just the next town over. A skinny, speedy man, he works at James Cook University in Cairns and knows most of northern Queensland like the back of his hand.

Cairns is on the coast at the upper right, where the little green airplane is.

The ferns I’m looking for today are interesting because some species can move from their original home in Australia to the tiny islands in the Pacific. But some cannot. Why? Understanding what makes them different could prove useful in making our crops more resilient to harsh weather, or preventing weeds from spreading.

We’ve been driving for four hours before we turn off onto a dirt road. If you haven’t been to Australia, it’s worth noting that four hours here is unlike any four hours I’ve experienced before. The roads are fairly empty, flat, and straight, meaning you can cover a lot of terrain. Australia is also incredibly big and most of the time you’re travelling through unpopulated landscapes. While it may be only four hours, your mind feels the weight of the distance.

Here’s the one they were looking for!
Cheilanthes tenuifolia with lots of little spore babies on the undersides of its leaves.

The dirt road begins to climb into the mountains. We are leaving behind low scrub and big granite rocks that sit on the flat terrain. Ashley knows where we can find the ferns I’m looking for, but he’s never driven this road before. Instead, we’re trusting researchers who came before us. When they explored this area, they took samples of plants that were preserved and stored in museums and universities. By reviewing the carefully labelled collections at these institutions, we can know which places to revisit in hopes of finding the ferns.

Often, however, having been collected before there was GPS, the location information on these samples is not very precise, or the plants may no longer live there, or maybe that area got turned into a parking lot, as happened to me in New Zealand. So, despite careful planning, you may drive five hours one way to come up empty handed.

As we move higher up the mountain, the soil turns redder and sparse eucalyptus forests begin to enclose us. We locate the previous collections coordinates, an area that seems suitable for ferns to grow. We park the truck on the side of the road and get out to look.

We comb 300 feet along the side of the road because these ferns like the edges of forest, and we find nothing. But as we trudge back to the truck, I spot one meager fern hiding behind a creeping vine! It’s high up off the road-cut and I try to scramble up but only manage to pull a muscle in my arm. Ashley is taller, so he climbs partway up a tree and manages to fetch the fern. It’s not the healthiest, only 6 inches tall for a plant that usually grows at least 12 to 14 inches. It’s also not fertile, making it less useful for research, and in pulling it out of the ground, Ashley broke one of its three leaves off. But it’s better than nothing!

This delicate beauty has no name yet. Karla has to compare it to other ferns in the area to know whether it’s just an odd-looking variant or possibly … a new species!

Ashley excels at being a field botanist because he is not one to give up. “We should keep looking,” he says despite the sweat dripping down our faces.

We pile back in and continue up the road. And who could have predicted that just around the bend we would find dozens of tall, healthy looking ferns! There are easily fifty or so plants, each a deep green, the tallest around 12 inches. Many others are at earlier stages of growth, which can be very helpful for scientists in understanding how plants develop. We take four or five plants, enough to leave a sample at the university in Cairns and for the rest to be shipped back to the US. One sample will be kept at Duke, and the others will be distributed amongst other museums and universities as a type of insurance.

The long hours, the uncertainty, and the harsh conditions become small things when you hit a jackpot like this. Plus, being out in remote wilderness has its own soothing charm, and chance also often allows us to spot cool animals, like the frilled lizard and wallaby we saw on this trip.

Funding for this type of fieldwork is becoming increasingly rare, so I am grateful to the National Geographic Society for seeing the value in this work and funding my three-week expedition. I was able to cover about 400 miles of Australia from north to south, visiting twenty-four different sites, including eight parks, and ranging from lush rainforest to dry, rocky scrub. We collected fifty-five samples, including some that may be new species, and took careful notes and photographs of how these plants grow in the wild, something you can’t tell from dried-up specimens.

Knowing what species are out there and how they exist within the environment is important not only because it may provide solutions to human problems, but also because understanding what biodiversity we have can help us take better care of it in the future.

Guest Post by graduate student Karla Sosa

Malaria Hides In People Without Symptoms

It seems like the never-ending battle against Malaria just keeps getting tougher. In regions where Malaria is hyper-prevalent, anti-mosquito measures can only work so well due to the reservoir that has built up of infected humans who do not even know they carry the infection.

In high-transmission areas, asymptomatic malaria is more prevalent than symptomatic malaria. Twenty-four percent of the people in sub-Saharan Africa are estimated to harbor an asymptomatic infection, including 38 to 50 percent of the school-aged children in western Kenya. Out of the 219 million malaria cases in 2017 worldwide, over 90%  were in sub-Saharan Africa.  

Using a special vacuum-like tool, Kelsey Sumner, a former Duke undergraduate now completing her Ph.D. at UNC-Chapel Hill, collected mosquitoes in households located in rural western Kenya. These weekly mosquito collections were a part of her pre-dissertation study on asymptomatic, or invisible, malaria. She visited Duke in September to catch us up on her work in Data Dialogue event sponsored by the mathematics department.

Sumner and colleague Verona Liao, in front of a sticky trap for mosquitoes

People with asymptomatic malaria carry the infection but have no idea they do because they do not have any indicators. This is incredibly dangerous because without symptoms, they will not get treated and can then infect countless others with the disease. As a result, people with an asymptomatic infection or infections have become a reservoir for malaria — a place for it to hide. Reservoirs are a group that is contributing to transmission at a higher rate or proportion than others.

Sumner’s study focused on examining the effect of asymptomatic malaria on malaria transmission as well as whether asymptomatic malaria infections would protect a person against future symptomatic infections from the same or different malaria infections. They were particularly looking into Plasmodium falciparum malaria. In Kenya, more than 70% of the population lives in an area with a high transmission of this potentially lethal parasite.

“P. falciparum malaria is very diverse in the region,” she said. “It’s constantly mutating, which is why it’s so hard to treat. But because of that, we’re able to actually measure how many infections people have at once.” 

The researchers discovered that many study participants were infected with multiple, genetically-distinct malaria infections. Some carried up to fourteen strains of the parasite.

Participants in the study began by filling out an enrollment questionnaire followed by monthly questionnaires and dried blood spot collections. The project has collected over nearly 3,000 dried blood spots from participants. These blood spots were then sent to a lab where DNA was extracted and tested for P. falciparum malaria using qPCR

“We used the fact that we have this really diverse falciparum species in the area and sequenced the DNA from falciparum to actually determine how many infections people have,” Sumner said. “And then, if there’s a shared infection between humans and mosquitoes.”

Sumner and her team also visited symptomatic participants who would fill out a behavioral questionnaire and undergo a rapid diagnostic test. Infected participants were able to receive treatment. 

While people in the region have tried to prevent infection through means like sleeping under insecticide-treated nets, malaria has persisted. 

One of the Kenyan staff members hanging a CDC light trap for mosquitoes

Sumner is continuing to analyze the collected DNA to better understand asymptomatic malaria, malarial reservoirs and how to best intervene to help stop this epidemic. 

“We’re basically looking at how the number of shared infections differ between those that have asymptomatic malaria versus those that have symptomatic malaria.”

She and her team hypothesize that there are more asymptomatic infections that would result in and explain the rapid transmission of malaria in the region.

Post by Anna Gotskind

Meet the New Blogger: Meghna Datta

Hi! My name is Meghna Datta, and I’m a freshman. I’m from Madison, Wisconsin, so North Carolina weather has been quite the adjustment. Apart from the humidity, though, I’m so excited to be at Duke! I’m an aspiring pre-med student with absolutely no idea what I want to major in. And it’s funny that I’ve grown to love science as much as I do. Up until tenth grade, I was sure that I would never, ever work in STEM.

My first love was the humanities. As a child I was hooked on books (still am!) and went through four or five a week. In high school, I channeled my love for words into joining my school’s speech and debate team and throwing myself into English and history classes, until being forced to take AP Biology my sophomore year completely changed my trajectory.

Science had always bored me with its seemingly pointless intricacies. Why would I want to plod through tedious research when I could be covering a groundbreaking story or defending justice in a courtroom instead? But the lure of biology for me was in its societal impact. Through research, we’ve been able to cure previously incurable diseases and revolutionize treatment plans to affect quality of life.

Meghna Datta repping the Devils

In AP Bio, understanding the mechanisms of the human body seemed so powerful to me. Slowly, I began to entertain the notion of a career in medicine, one of many scientific fields that works to improve lives every day.

Now, the research going on at Duke doesn’t cease to amaze me. Specifically, I’m interested in science for social good. Be it sustainable engineering, global health, or data-driven solutions to problems, I love to see the ways in which science intersects with social issues. As I have learned, science does not need to be done in isolation behind pipettes. Science is exciting and indicative of society’s shared sense of humanity. At Duke, there’s no shortage of this environment.

As a blogger I’m so excited to see the inspiring ways that peers and faculty are working to solve problems. And because science isn’t a traditionally “showy” field, I am looking forward to shining the spotlight on people at Duke who tirelessly research behind the scenes to impact those at Duke and beyond. The research community at Duke has so much to celebrate, and through blogging I’m excited to do just that!

Legendary Paleontologist Richard Leakey Visits Duke

Hoping to catch up with an old friend who is a professor at Duke, Richard Leakey accepted an invitation to speak at the university on Oct. 22, though he “gave up public speaking to a large extent many years ago.”

Richard E. Leakey visited Duke on Oct. 22, 2019.

Leakey, age 74, is a world-renowned pioneer in Paleoanthropology – the study of the human fossil record – and is also well-known for his involvement in Kenyan politics and lifelong efforts towards conservation and wildlife protection. Once, he famously burned twelve tons of elephant tusks that were confiscated from poachers, which gathered international attention and helped usher in a global ban on the ivory trade.

Leakey came to paleontology by heredity. He is one of an entire family of Paleo-pioneers. His mother, Mary, discovered a skull in Africa that was dated to 1.75 million years ago (MYA) in 1960. Leakey said that this “electrified interest in the origin story” – that is, the human origin story. When his father, Louis, showed that the “quite clever” ancient tools he had discovered were made around 1.75 MYA, the original idea that human origins began outside of Africa began to change.

Leakey said the British people were hoping that “if we had evolved … let it happen in England” and if not England, then Asia, but this was not to be the case. At first, Louis Leakey was ostracized because of his work and discoveries of human origins in Africa. This helped steer Richard away from academics because of the fights that he saw his father endure.

Leakey’s famous 1984 Kenyan discovery, “Turkana Boy,” a 1.5 million-year-old, nearly-complete specimen of Homo erectus. (Wikipedia)

Successfully achieving his self-described ambition to not finish high school, Richard Leakey was thrown out of school at age 16. Yet today he is accredited with many awards, has written at least eight books, and has advanced the Leakey family legacy of discovery. From 1968 to the present day, he and fellow workers have discovered enormous numbers of fossils of our ancestors along the East and West shores of Lake Turkana in Kenya, which have an age span from 4.5 MYA to our very recent ancestors, which Leakey calls “fossil us.”

Leakey described for the Duke audience in an overflowing auditorium at the Nasher Museum a scenario he facilitated with colleagues and students.

He had taken a group to a camp site to talk about evolution and asked them to perform some tasks. First, they were charged to make tools from stone. The following day, they were led to a freshly slaughtered goat. Leakey told his pupils to butcher the goat and remove the flesh from its carcass.

After several hours watching the individuals try to pull at the goat with their hands to no avail, Leakey suggested that they might use their new stone tools. So they did, but they still could not get through the animal’s tough hide, even with a blade.

He said that during human evolution, our imagination was turned on genetically and this gave early humans the “capability to think of things that weren’t.” There is lots of work to be done studying an ancient period over 3.5 million years that Leakey says lends itself to “early ancestry of speech, imagination, [and] cooperation.” He is hopeful for the knowledge and new understandings that will come from investigation of this period. 

“Why not ask someone to help you?” Leakey prompted again, and within an hour, nothing was left of the goat. The exercise demonstrated that though other monkeys and apes use stone, it is the human’s vocal communication and sense of working together that sets us apart, says Leakey.     

Leakey’s current project is a “mega-museum” to “cerebrate and celebrate the story of the African origin.” The origin story which his parents first provided crucial evidence for is hugely important to the African continent and to the people of Africa and because we have “desecrated our motherland,” he said. Leakey wants the museum to highlight stages of evolution, genetics, climate, ecology, other species, and extinctions.

An architectural rendering of Ngaren: The Museum of Humankind to be built near Nairobi. (Studio Libeskind )

Before moving into the panel and Q&A portion of his talk, which was moderated by Duke professors Steven Churchill and Anne Yoder, Leakey prompted the audience to think about climate change, asking why we do not think we need to save ourselves. If we die, then other species go with us.

“Don’t for a minute think that climate change isn’t a real crisis that we’re in together,” Leakey said, earning a round of applause.

Post by Cydney Livingston

These Microbes ‘Eat’ Electrons for Energy

The human body is populated by a greater number of microbes than its own cells. These microbes survive using metabolic pathways that vary drastically from humans’.

Arpita Bose’s research explores the metabolism of microorganisms.

Arpita Bose, PhD, of Washington University in St. Louis, is interested in understanding the metabolism of these ubiquitous microorganisms, and putting that knowledge to use to address the energy crisis and other applications.

Photoferrotrophic organisms use light and electrons from the environment as an energy source

One of the biggest research questions for her lab involves understanding photoferrotrophy, or using light and electrons from an external source for carbon fixation. Much of the source of energy humans consume comes from carbon fixation in phototrophic organisms like plants. Carbon fixation involves using energy from light to fuel the production of sugars that we then consume for energy.

Before Bose began her research, scientists had found that some microbes interact with electricity in their environments, even donating electrons to the environment. Bose hypothesized that the reverse could also be true and sought to show that some organisms can also accept electrons from metal oxides in their environments. Using a bacterial strain called Rhodopseudomonas palustris TIE-1 (TIE-1), Bose identified this process called extracellular electron uptake (EEU).

After showing that some microorganisms can take in electrons from their surroundings and identifying a collection of genes that code for this ability, Bose found that this ability was dependent on whether a light source was also present. Without the presence of light, these organisms lost 70% of their ability to take in electrons.   

Because the organisms Bose was studying can rely on light as a source of energy, Bose hypothesized that this dependence on light for electron uptake could signify a function of the electrons in photosynthesis.  With subsequent studies, Bose’s team found that these electrons the microorganisms were taking were entering their photosystem.

To show that the electrons were playing a role in carbon fixation, Bose and her team looked at the activity of an enzyme called RuBisCo, which plays an integral role in converting carbon dioxide into sugars that can be broken down for energy. They found that RuBisCo was most strongly expressed and active when EEU was occurring, and that, without RuBisCo present, these organisms lost their ability to take in electrons. This finding suggests that organisms like TIE-1 are able to take in electrons from their environment and use them in conjunction with light energy to synthesize molecules for energy sources.  

In addition to broadening our understanding of the great diversity in metabolisms, Bose’s research has profound implications in sustainability. These microbes have the potential to play an integral role in clean energy generation.

Post by undergraduate blogger Sarah Haurin
Post by undergraduate blogger Sarah Haurin

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