The monarch defense: In chess and in life

Emory evolutionary biologist Jaap de Roode has had some strange assignments in his academic career. In his early days as a researcher, for example, his job was to measure the penis size of Malaysian dung beetles.

So it was no big deal when a photographer for Popular Science magazine asked de Roode to pose at a chessboard, pretending to watch two opponents: A butterfly and a bio-hazard bottle that was standing in for a parasite. The photo shoot was to illustrate the Popular Science “Brilliant 10,” top scientists under 40 from across the nation recognized by the editors of the magazine.

De Roode was declared “Brilliant” for his discovery of how monarch butterflies treat themselves and their offspring for parasites, using medicinal plants.

“I liked the concept of the chess game,” says de Roode. “That really is how scientists view the co-evolutionary process of a host and its parasites. One makes a move, and the other responds with a defense or attack.”

Many scientists have argued that animal medication requires great cognitive ability, memory and learning behaviors, and that self-medication may be restricted to a handful of animals, such as chimpanzees and gorillas. Research by the de Roode lab, however, clearly shows that very simple and small-brained animals can use “natural” medicine.

De Roode’s findings, which were published in Ecology Letters, suggest that animal medication is probably much more widespread than originally thought, opening the door for many new discoveries of medication in nature.

Currently, de Roode is studying different populations of monarchs, to determine whether they use medication only therapeutically, when they are already infected with parasites, or as a preventative, when they live in areas with a higher risk of infection.

He explains the hypothesis with a human analogy: “If we travel to Africa, we may take anti-malaria drugs prophylactically, but while we’re at home in the United States we don’t use them. You don’t want to take drugs when you don’t need them.”

In previous work, de Roode provided a new perspective on another long-standing question in evolutionary ecology: How do parasites strike the balance between living off of their hosts and killing them?

A prevalent theory – still proclaimed by most medical doctors – was that over time, parasites become less virulent and evolve a capacity to be nearly harmless to their hosts.

De Roode’s work revealed a different underlying strategy, showing that instead of becoming kinder, parasites may actually be selected to be virulent and deadly. By doing so, they produce more offspring, which increases the chances of the parasite jumping to new hosts.

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Artist brings original 'warm pond' to life

For her latest work, including "Warm Pond," above, Atlanta artist Terri Dilling is drawing her inspiration from Earth's primordial soup, where chemical reactions may have created life on the planet some 3.5 billion years ago. Her exhibit "Assembly" opens at the Portal Gallery with a reception on Friday, September 23 at 7 p.m. and continues through October 30.

The prints and paintings were informed by conversations with scientists from the Center for Chemical Evolution during the past seven months. "Although their research is complex, I think scientists are asking very basic questions about what the world is made of and how it works," Dilling says. "As an artist, I'm asking similar questions."

The NSF/NASA Center for Chemical Evolution involves scientists from Emory, Georgia Tech and other institutions, stretching from California to Italy. The visiting artist program is an educational initiative of the CCE to raise awareness about research in chemical evolution, the process of how simple atoms and molecules might form bigger and more complex structures.

"Chemistry has been an interesting influence, causing me to look at my art in a new way," Dilling says.

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Biochemical cell signals quantified for first time

Can you hear me now? When you feel symptoms of a nasty bug, you phone the doctor. Cells in your body are also receiving “calls,” through a biochemical signaling pathway that turns out to have surprisingly low data capacity. 

By Carol Clark

Just as cell phones and computers transmit data through electronic networks, the cells of your body send and receive chemical messages through molecular pathways. The term “cell signaling” was coined more than 30 years ago to describe this process.

Now, for the first time, scientists have quantified the data capacity of a biochemical signaling pathway and found a surprise – it’s way lower than even an old-fashioned, dial-up modem.

“This key biochemical pathway is involved in complex functions but can transmit less than one bit – the smallest unit of information in computing,” says Ilya Nemenman, an associate professor of physics and biology at Emory University. “It’s a simple result, but it changes our view of how cells access chemical data.”

The journal Science is publishing the discovery by Nemenman and colleagues from Johns Hopkins University, including Andre Levchenko, Raymond Cheong, Alex Rhee and Chiaochun Joanne Wang.

During the 1980s, cell biologists began identifying key signaling pathways such as nuclear factor kappa B (NF-kB), known to control the expression of genes in response to everything from invading pathogens to cancer. But the amount of information carried by chemical messengers along these pathways has remained a mystery.

“Without quantifying the signal, using math and computer analysis to attach a number to how much information is getting transmitted, you have a drastically incomplete picture of what’s going on,” says Nemenman, a theoretical biophysicist.

He and Levchenko, a biomedical engineer, began discussing the problem back in 2007 after they met at a conference.

Click on NF-kB graphic, below, to enlarge it:


NF-kB is a protein complex that is a key element of a biochemical signaling pathway involved in cellular responses to a range of stimuli. Graphic: Wikipedia Commons.

Levchenko provided the experimental framework to measure the transmissions occurring on the pathway in many thousands of cells at one time. Nemenman formulated the theoretical framework to analyze and quantify the results of the experiments. Graduate student Raymond Cheong developed and conducted the experiments and performed much of the analysis.

“It was a shock to learn that the amount of information getting sent through this pathway is less than one bit, or binary digit,” Nemenman says. “That’s only enough information to make one binary decision, a simple yes or no.”

And yet NF-kB is regulating all kinds of complex decisions made by cells, in response to stimuli ranging from stress, free radicals, bacterial and viral pathogens and more. “Our result showed that it would be impossible for cells to make these decisions based just on that pathway because they are not getting enough information,” Nemenman says. “It would be like trying to send a movie that requires one megabit per second through an old-style modem that only transmits 28 kilobits per second.”

They analyzed the signals of several other biochemical pathways besides NF-kB and got a similar result, suggesting that a data capacity of less than one bit could be common. So if cells are not getting all the information through signaling pathways, where is it coming from?

“We’re proposing that cells somehow talk with each other outside of these known pathways,” Nemenman says. “A single cell doesn’t have enough information to consider all the variables and decide whether to repair some tissue. But when groups of cells talk to each other, and each one adds just a bit of knowledge, they can make a collective decision about what actions to take.”


He compares it to a bunch of people at a cocktail party, with cell phones that have weak signals pressed to their ears. Each person is receiving simple messages via their phones that provide a tiny piece to a puzzle that needs to be solved. When the people chatter together and share their individual messages, they are able to collectively arrive at a reliable solution to the puzzle.

A similar phenomenon, called population coding, had been identified for the electrical activity of neural networks, but Nemenman and his colleagues are now applying the idea to bio-chemical pathways.

They hope to build on this research by zeroing in on the role of cell signaling in specific diseases.

In particular, Nemenman wants to analyze and compare the signaling capacities of a cancerous cell versus a normal cell.

“Cancerous cells divide when they shouldn’t, which means they are making bad decisions,” he says. “I would like to quantify that decision-making process and determine if cancer cells have reduced information transduction capacities, or if they have the same capacities as healthy cells and are simply making wrong decisions.”

Nemenman uses a malfunctioning computer as an example. “If you push the ‘a’ key on your computer and a ‘d’ always shows up, that means the computer is misprogrammed but the information from your keystroke gets through just fine,” he says. “But if you keep pressing the letter ‘a’ and different, random letters show up, that indicates a problem with the way the information is being transmitted.”

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CDC disease detectives to chat live online

Epidemics have been with us since people began living in cities. “An almost inevitable accompaniment to the fevers, and the coughs and other symptoms of these epidemics has been fear,” says Jeffrey Koplan, director of the Emory Global Health Institute and a former director of the CDC.

The hit movie “Contagion” begs the question, how will the CDC control the next outbreak and the public panic? You can ask CDC experts, including members of the elite Epidemic Intelligence Service, during two live Twitter chats, on Friday, Sept. 16 and Monday, Sept. 19 from 2 to 3 p.m.

You can follow #CDCcontagion live on Twitter, and you can also submit questions in advance to @CDCgov.

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Rare mummy gets new lease on the afterlife

Conservators put the finishing touches on what was a major makeover for the 4,000-year-old mummy, one of only half-a-dozen in the world dating back to Egypt's Old Kingdom.

By Margie Fishman, Emory Report

The mummy from 2300 B.C. was in a sorry state when he arrived at Emory in 1921. Headless, his neck bones had tumbled into his abdominal cavity. Gaping holes and sagging linens marred vague remnants of shoulders, hips and knees. One conservator likened his physique to a crushed bag of potato chips.

Today, the oldest Egyptian mummy in North America has a new lease on the afterlife and is featured in a Michael C. Carlos Museum exhibit, thanks to a patient group of Emory conservation experts, anthropologists and doctors.

"Life and Death in the Pyramid Age: The Emory Old Kingdom Mummy" places the mummy in the context of ancient Egypt's burial rites and rituals, along with exploring the social and political changes at the end of the Pyramid Age. Approximately 120 objects from the Carlos Museum's collection and borrowed from other museums and private collectors will be on display through Dec. 11.

They include a life-size replica of an Old Kingdom tomb, "magic" vessels and wands used to recite spells on the dead, and a rare statue of Pharaoh Pepi, who ruled during the mummy's lifetime.

"This mummy is a very important piece. We've finally been able to conserve it and put it on display," says Peter Lacovara, the Carlos Museum's senior curator of ancient Egyptian, Nubian and near Eastern art.

Listen to leading Egyptologists discuss the history of the mummy and the site where it originated:



It was a long road to get the mummy ready for prime time.

Acquired by Emory theology professor William A. Shelton in 1920, the mummy was the first inventoried object in what was then the Emory University Museum of Art and Archaeology.

Dismissed as a massive reconstruction effort, the mummy was squirreled away in two crates in storage (one for his body and one for his head, that had fallen off).

At Lacovara's nudging, the mummy identified as "1921.1" was retrieved about a year ago and carefully transported to Emory University Hospital for X-ray and CT radiographic imaging.

Modern technology revealed much about the early mummification process, which used a combination of salts, oils and resin. It also permitted the conservation team to peer inside the mummy to assess the body's condition without actually unwrapping him. Exposing the body would have been disrespectful as well as damaging, notes Carlos conservator Renee Stein.

"The overarching goal of the project was to restore some structural integrity to the body and dignity to human remains," she says.

The mummy predates the period when the brain was removed during the embalming process, and the head contained a walnut-sized piece of material that appears to be the dessicated brain.

With the help of radiology professor William Torres, who has examined several Carlos mummies, the conservation team learned that the mummy's bones were well-mineralized, it hadn't suffered any major head trauma and it hadn't been prone to ear infections. Although his pelvis was obscured, the group determined that the mummy was most likely a male, given the size and shape of his skull.

All in all, "this was a pretty healthy individual," says Emory anthropologist George Armelagos, who was involved in the examination effort.

In light of the physical evidence and that the mummy had been buried at a holy site, conservators safely assumed that the mummy had access to a good diet and other social advantages. The cause of death, however, remained a mystery.

The Carlos Museum called on Mimi Leveque, a freelance conservator from Boston. Leveque has lent her expertise to several of the dozen mummies in the Carlos collection, the youngest of which is 2,000 years old.

One of the most glaring issues with the Old Kingdom mummy was his displaced head. The mummy originally was laid on his right side (a common burial position at the time), his head supported by a headrest. Over time, the headrest had been lost, along with the bulk of his coffin, leaving the head unsupported.

In the slideshow below, see images of the mummy before the makeover, and listen to Egyptologists discuss mummy science:



As a solution, Leveque relied on low-tech methods, carving out a piece of archival-quality foam and wedging it in the hollow between the mummy's collar bones and shoulder blades. She then threaded a padded dowel in the foam and through the hole at the base of the skull.

The mummy's jaw was cast from a mold from a similarly-sized, more modern jaw from Armelagos' lab. Two undergraduate interns used an epoxy putty to form missing bones for the hands and feet. They placed the bones inside padded papier-mache forms, wrapped in modern linen that was dyed to match the ancient wrappings.

Once intact, the mummy appeared lifelike, as if he had just lain down to sleep.

Eventually the mummy, one of only a half-dozen from that period who have survived, will be a permanent fixture at the Carlos. Due to his fragility, he will not tour.

Ancient Egyptians believed that by visiting tombs and actively remembering the dead through images, mummies were kept alive in the afterlife, explains Lacovara.

"In recreating the tomb and restoring the Old Kingdom mummy, we are fulfilling his wish," he says.

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