Brain trumps hand in Stone Age tool study

By Carol Clark

Was it the evolution of the hand, or of the brain, that enabled prehistoric toolmakers to make the leap from simple flakes of rock to a sophisticated hand axe?

A new study finds that the ability to plan complex tasks was key. The research, published today in the Public Library of Science journal PLoS ONE, is the first to use a cyber data glove to precisely measure the hand movements of stone tool making, and compare the results to brain activation.

“Making a hand axe appears to require higher-order cognition in a part of the brain commonly known as Broca’s area,” said Emory anthropologist Dietrich Stout, co-author of the study. It’s an area associated with hierarchical planning and language processing, he noted, further suggesting links between tool-making and language evolution.

“The leap from stone flakes to intentionally shaped hand axes has been seen as a watershed in human prehistory, providing our first evidence for the imposition of preconceived, human designs on the natural world,” he said.
"For the past two million years, stone tool making has been the most common and consistent human technology," Stout says. Photo by Carol Clark.

Stout is an experimental archeologist who recreates prehistoric tool making to study the evolution of the human brain and mind. Subjects actually knap tools from stone as activity in their brains is recorded. (Watch the video, above, to see how Stone Age tools were made.)

“Changes in the hand and grip were probably what made it possible to make the first stone tools,” Stout said. “Increasingly we’re finding that the earliest tools required visual and motor skills, but were conceptually simple.”

For this study, Stout used a data glove to record the exact hand postures of the research subject across a range of prehistoric technologies. He teamed with Aldo Faisal, a neuroscientist at Imperial College London, and archeologists Jan Apel of Gotland University College in Sweden and Bruce Bradley of Exeter University in Devon, England.

The researchers compared the manual dexterity for the tasks involved in making two types of tools: Oldowan flakes and Late Acheulean hand axes. Simple Oldowan stone flakes are the earliest known tools, dating back 2.6 million years. The Late Acheulean hand axe, going back 500,000 years, embodies a higher level of refinement and standardization.

“I assumed that the manual dexterity was going to be greater for making the hand axe,” Stout said. “But we found that the hand gestures were so similar that we couldn’t distinguish them.”
The leap from stone flakes to a hand axe was "a watershed in human prehistory," Stout says. Photo by Carol Clark.

A previous study by Stout found differences in the brain activation associated with Oldowan versus Acheulean technologies. It was unclear, however, whether the difference was due to higher-level behavior organization or lower-level differences in manipulative complexity.

The results of the data glove study point to higher cognition. “The advances of Late Acheulean technology were not about increased dexterity. They were about the ability to plan complex action sequences,” Stout said.

A hand axe requires the maker to begin with a precise, symmetrical end in mind. A variety of tools are involved, from a large rock to rough out the basic shape of the axe, to a softer implement, such as an antler billet, to thin and sharpen the edges.

The ongoing research could lead to new understanding of the modern human brain. “For the past two million years, stone tool-making has been the most common and consistent human technology, done by virtually every society,” Stout said. "It’s an important human behavior that probably helped shape our brains.”

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Morals without God?

Emory psychologist Frans de Waal writes an opinion piece in the New York Times:

I was born in Den Bosch, the city after which Hieronymus Bosch named himself. This obviously does not make me an expert on the Dutch painter, but having grown up with his statue on the market square, I have always been fond of his imagery, his symbolism, and how it relates to humanity’s place in the universe. This remains relevant today since Bosch depicts a society under a waning influence of God. His famous triptych with naked figures frolicking around, “The Garden of Earthly Delights,” seems a tribute to paradisiacal innocence. The tableau is far too happy and relaxed to fit the interpretation of depravity and sin advanced by puritan experts. It represents humanity free from guilt and shame either before the Fall or without any Fall at all.
Detail from "The Garden of Earthly Delights" by Hieronymus Bosch. The painting combines references from religion, nature and science. Source: Wikipedia Commons.

For a primatologist, like myself, the nudity, references to sex and fertility, the plentiful birds and fruits and the moving about in groups are thoroughly familiar and hardly require a religious or moral interpretation. Bosch seems to have depicted humanity in its natural state, while reserving his moralistic outlook for the right-hand panel of the triptych in which he punishes — not the frolickers from the middle panel — but monks, nuns, gluttons, gamblers, warriors, and drunkards.

Five centuries later, we remain embroiled in debates about the role of religion in society. As in Bosch’s days, the central theme is morality. Can we envision a world without God? Would this world be good? Don’t think for one moment that the current battle lines between biology and fundamentalist Christianity turn around evidence. One has to be pretty immune to data to doubt evolution, which is why books and documentaries aimed at convincing the skeptics are a waste of effort. They are helpful for those prepared to listen, but fail to reach their target audience. The debate is less about the truth than about how to handle it. For those who believe that morality comes straight from God the creator, acceptance of evolution would open a moral abyss.

Read the whole article in the New York Times.

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The monarch butterfly's medicine kit

The journal Ecology Letters just published findings by Emory biologists that monarch butterflies use medication to cure themselves and their offspring of disease.

So what’s in a monarch’s medicine kit? Milkweed – but only a particular species. Experiments show that egg-laying monarchs that are infected with a parasite choose plants that have a medicinal benefit for their caterpillars.

“We believe that our experiments provide the best evidence to date that animals use medication,” says evolutionary biologist Jaap de Roode, who led the research.

Watch the video to learn more, and get a tour of one of the few labs in the world studying monarch butterflies.

Photo at left of a monarch laying her eggs by Jaap de Roode.

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Do monarch butterflies use drugs?

Photos by Jaap de Roode and Lisa Sharling.

By Carol Clark

Emory biologists are studying whether monarch butterflies can cure themselves and their offspring of disease by using medicinal plants. The National Science Foundation recently awarded Jaap de Roode a $500,000 grant to further his research, which focuses on the behavior of monarchs infected with a protozoan parasite.

“We have shown that some species of milkweed, the larva’s food plants, can reduce parasite infection in the monarchs,” says de Roode, (in photo, at left) assistant professor of biology. “And we have also found that infected female butterflies prefer to lay their egg on plants that will make their offspring less sick, suggesting that monarchs have evolved the ability to medicate their offspring.”

Few studies have been done on self-medication by animals, but some scientists have theorized that the practice may be more widespread than we realize. “We believe that our experiments provide the best evidence to date that animals use medication,” de Roode says.

Take a video tour of the monarch butterfly lab.

“The results are also exciting because the behavior is trans-generational,” says Thierry Lefevre, a post-doctoral fellow in de Roode’s lab. “While the mother is expressing the behavior, only her offspring benefit.”

Monarch butterflies are known for their spectacular migration from the United States to Mexico each year, and for the striking pattern of orange, black and white on their wings. That bright coloration is a warning sign to birds and other predators that the butterfly may be poisonous.

Monarch caterpillars feed on any of dozens of species of milkweed plants, including some species that contain high levels of cardenolides. These chemicals do not harm the caterpillars, but make them toxic to predators even after they emerge as adults from their chrysalises.

Previous research has focused on whether the butterflies choose more toxic species of milkweed to ward off predators. De Roode wondered if the choice could be related to the parasite Ophryocystis elektroscirrha. The parasites invade the gut of the caterpillars and then persist when they become adult monarchs. An infected female passes on the parasites when she lays her eggs. If the adult butterfly leaves the pupal stage with a severe parasitic infection, it begins oozing fluids from its body and dies (see photo, at right). Even if the butterflies survive, they do not fly as well or live as long as uninfected ones.

Experiments in de Roode’s lab have shown that a female infected with the parasites prefers to lay her eggs on a toxic species of milkweed, rather than a non-toxic species. Uninfected female monarchs, however, showed no preference.

The Emory scientists will use the NSF grant to see if the lab results can be replicated in nature, across different populations of monarchs in various regions of the world. De Roode’s collaborator, chemical ecologist Mark Hunter of the University of Michigan, received $150,000 from the NSF to identify the chemicals that account for the medicinal properties of the milkweed plants.

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Ancient brewers tapped antibiotic secrets

The ancient Egyptians and Jordanians used beer to treat gum disease and other ailments.

By Carol Clark

A chemical analysis of the bones of ancient Nubians shows that they were regularly consuming tetracycline, most likely in their beer. The finding is the strongest evidence yet that the art of making antibiotics, which officially dates to the discovery of penicillin in 1928, was common practice nearly 2,000 years ago.

The research, led by Emory anthropologist George Armelagos and medicinal chemist Mark Nelson of Paratek Pharmaceuticals, Inc., is published in the American Journal of Physical Anthropology.

“We tend to associate drugs that cure diseases with modern medicine,” Armelagos says. “But it’s becoming increasingly clear that this prehistoric population was using empirical evidence to develop therapeutic agents. I have no doubt that they knew what they were doing.”

Armelagos is a bioarcheologist and an expert on prehistoric and ancient diets. In 1980, he discovered what appeared to be traces of tetracycline in human bones from Nubia dated between A.D. 350 and 550, populations that left no written record. The ancient Nubian kingdom was located in present-day Sudan, south of ancient Egypt.

Green fluorescence in Nubian skeletons indicated tetracycline-labeled bone, the first clue that the ancients were producing the antibiotic.

Armelagos and his fellow researchers later tied the source of the antibiotic to the Nubian beer. The grain used to make the fermented gruel contained the soil bacteria streptomyces, which produces tetracycline. A key question was whether only occasional batches of the ancient beer contained tetracycline, which would indicate accidental contamination with the bacteria.

Nelson, a leading expert in tetracycline and other antibiotics, became interested in the project after hearing Armelagos speak at a conference. “I told him to send me some mummy bones, because I had the tools and the expertise to extract the tetracycline,” Nelson says. “It’s a nasty and dangerous process. I had to dissolve the bones in hydrogen fluoride, the most dangerous acid on the planet.”

The results stunned Nelson. “The bones of these ancient people were saturated with tetracycline, showing that they had been taking it for a long time,” he says. “I’m convinced that they had the science of fermentation under control and were purposely producing the drug.”

(The yellow film in the flask, at right, shows tetracycline residue from dissolved bones.)

Even the tibia and skull belonging to a 4-year-old were full of tetracycline, suggesting that they were giving high doses to the child to try and cure him of illness, Nelson says.

Egyptian 12th-dynasty figures shows workers grinding, baking and fermenting grain, to make bread and beer. Source: Wikipedia Commons.

The first of the modern day tetracyclines was discovered in 1948. It was given the name auereomycin, after the Latin word “aerous,” which means containing gold. “Streptomyces produce a golden colony of bacteria, and if it was floating on a batch of beer, it must have look pretty impressive to ancient people who revered gold,” Nelson theorizes.

The ancient Egyptians and Jordanians used beer to treat gum disease and other ailments, Armelagos says, adding that the complex art of fermenting antibiotics was probably widespread in ancient times, and handed down through generations.

The chemical confirmation of tetracycline in ancient bones is not the end of the story for Armelagos. He remains enthused after more than three decades on the project. “This opens up a whole new area of research,” he says. “Now we’re going to compare the amount of tetracycline in the bones, and bone formation over time, to determine the dosage that the ancient Nubians were getting.”

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What young scientists do on vacation

Yamini Potini did evolutionary biology experiments with monarch butterflies.

Morgan Mingle spent her summer analyzing the musical tastes of chimpanzees. Julie Margolis cut up human bones with a bandsaw. Yamini Potini immersed herself in the world of monarch butterflies.

All three say they had a blast doing hands-on science that led to discoveries. They were part of this year’s Summer Undergraduate Research Program at Emory (SURE), which awards selected students a stipend, free housing, and a chance to work with top scientists.

Mingle, who won a spot in the lab of primatologist Frans de Waal, designed an experiment with chimpanzees to look deep into the evolutionary history of music. “Music is in every human culture, but we can’t figure out what makes it so biologically important to us. It’s a big mystery,” says Mingle, a neuroscience major from Southwestern University.

Mingle (below, center) with de Waal at the SURE poster session.

The chimps showed a preference for African and Indian tunes over Japanese music or silence. The Japanese recording may have put the chimps off because it resembled the rhythmic slapping and stamping sounds made by a male chimp displaying dominance, Mingle says. “Socko does amazing displays,” she adds, referring to a famous resident of Yerkes National Primate Research Center. “He keeps really good time.”

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Margolis, a junior entering Emory from Oxford College, analyzed tetracycline in ancient remains for bioarcheologist George Armelagos. “My mom used to bury animal bones in my sand box so I could dig them out,” Margolis says, explaining why she was thrilled to work alone in a basement with human skeletons. “This has been my passion since I was a little kid.”

She used a bandsaw to slice 1,000-year-old rib cages from Nubia into thin pieces. She submerged the bone slices in epoxy, then baked them and ground them down for slides. When she studied the samples under a microscope, she found markers for tetracycline spread throughout.

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“Tetracycline is an antibiotic that binds to calcium,” Margolis explains. Although the bones pre-date the official discovery of the drug, “it appears these people were ingesting tetracycline throughout their lifetimes.”

Her work supported Armelagos’ growing body of research into how tetracycline may have been a byproduct of an ancient beer-making process.

Potini, an Emory sophomore, also studied ancient forms of medication – involving monarch butterflies. Her project took her into the field and into a lab, where evolutionary biologist Jaap De Roode raises eastern monarch butterflies in flight cages. De Roode studies complex interactions between parasites that infect the butterflies, and toxic chemicals, known as cardenolides, in milkweed plants.

The study that Potini worked on found that females infected with parasites preferred to lay their eggs on plants with higher levels of cardenolides, raising the question of whether they have some kind of medicinal benefit.

“Self-medication probably occurs more often than we realize in wild life, but we don’t have a lot of data on it,” Potini says. Learning how insects self-medicate could provide clues to fight human parasitic diseases, such as malaria, she adds.

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Teaching evolution enters new era

A hypothetical young planet with a soupy mix of potentially life-forming chemicals pooling around the base of rocks. Drawing by NASA.

From fall to spring, Lakshmi Anumukonda is a science teacher at a metro-Atlanta high school. But in the summer, she dons a lab coat and becomes a molecular time traveler.

“It’s exciting,” she said. “We’re looking at chemical bonding and primitive elements that were present on prebiotic Earth.”

Anumukonda is exploring the origins of life some 3.5 billion years ago through the Center for Chemical Evolution. Several dozen middle- and high-school teachers are involved in the virtual center (formerly known as the Origins Project).

The roots of the Center for Chemical Evolution go back nearly a decade, growing out of collaborations between Emory and Georgia Tech. The latest phase of the venture launched this week, fueled by a $20 million grant from the National Science Foundation and NASA. The center now encompasses 15 laboratories at institutions including Emory, Georgia Tech, the Scripps Research Institute, the Scripps Institution of Oceanography, Jackson State University, Spelman College, Furman University and the SETI Institute.

The center’s mission “gives me goose bumps,” said Matthew Platz, incoming director of the NSF Division of Chemistry. Platz recalled his own sense of wonder in high school, when he learned about the 1953 Miller-Urey experiment. That was the first demonstration that Earth’s primordial soup favored chemical reactions that could lead to organic compounds.

“I thought that was incredibly cool,” Platz said. “For more than 40 years, I’ve been waiting to learn the next step: how these chemical reactions created life on this planet. Now we have the technology to take on that question.”

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As the university scientists seek to unravel how life began, the high school teachers are seeking ways to connect their students to the discoveries.

“I’m learning so much,” Anumukonda said. “Our high school textbooks talk about the prebiotic soup experiment and then stop there. After that, we have no idea about the recent research.”

A supernova explodes, below, scattering elements of which we and the Earth are made into space. Credit: Hubble Heritage Team, Y. Chu, NASA.

This summer, she worked alongside scientists in the lab of David Lynn, chair of chemistry at Emory. Lynn leads research into molecular self-assembly and other forces of evolution, along with the center’s education and outreach component.

Anumukonda used her lab experience to develop lesson plans for the self-assembly of molecules. This fall, her high school students will prepare samples of sodium acetate, and then take a field trip to Emory, where they can see through an electron microscope how their samples crystallize under different conditions.

“It’s wonderful to learn about the potential for real-world applications,” said Robert Hairston, another high school science teacher who spent much of his summer in Lynn’s lab. He was intrigued by how the forces of evolution could be harnessed to help in drug design and genome engineering.

“When I bring my students to Emory in the fall, I want them to have questions already in mind,” Hairston said. “They’re going to be amazed when they see the work that is being done.”

Emory seeded the educational component of the center through an “Evolution Revolution” symposium, teacher workshops, theatrical performances, visual arts and public talks to bring people together to discuss the topic.

“Emory is the perfect place to experiment with ways to improve the public’s understanding of evolution,” Lynn said. “We’ve taken the lead in addressing an issue that is sometimes charged and fractious in the Southeast, when it should be unifying.”

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Dogs may help collar Chagas disease

Mongrel dogs have a hardscrabble life in poor, rural communities of Argentina.

Some diseases, like stray dogs, are largely neglected by society.

Chagas disease, for example, is caused by a parasite that roams with only limited control among the rural poor in Latin America. The main vector for the parasite Trypanosoma cruzi is the triatomine insect, or “kissing bug,” which thrives in the nooks and crannies of mud-brick dwellings. The bug sucks the blood of mammals, helping T. cruzi move between wildlife, cats, dogs and humans.

“Dogs tend to lie on porches or other areas easily accessible to the bugs,” says disease ecologist Uriel Kitron, chair of environmental studies at Emory. “And when a dog is malnourished and its immune system isn’t great, they are even more at risk.”

Kitron has been researching Chagas disease in remote communities of northern Argentina for the past 10 years. “One of our most significant findings is the importance of dogs in both the spread of the disease, and the potential to help control it,” he says, explaining that dogs can make good sentinels for health officials monitoring T. cruzi transmission.

Chagas disease begins as an acute infection that can subside on its own. In one out of three cases, however, the infection persists and can go unnoticed for decades, until it causes complications such as heart failure, digestive problems and sudden cardiac death. The condition affects 10 to 12 million people in Latin America, killing more than 15,000 a year.

Human migration has moved Chagas disease around the globe: U.S. blood banks must now screen donors for T. cruzi. And bugs travel hidden in people’s luggage to new places such as Patagonia in southern Argentina.

Kitron is collaborating with Ricardo Gürtler of the University of Buenos Aires on a research project funded through a joint NIH-NSF program on the ecology of infectious diseases. Their work in Argentina’s Chaco province is included in a June 24 special supplement of Nature, devoted to the topic of Chagas disease.

“We are interested in answering scientific questions, but we also want to help reduce the risk and the impact of the disease on the rural population,” Kitron says.

Few government resources make it to the rural poor, and the main control for Chagas disease is spraying insecticide. “It’s a limited strategy,” Kitron says. “If you want to control Chagas disease, you have to look at the whole picture.”
A mud-brick home is emptied of its contents, before spraying with insecticide.

The researchers have shown, for example, that people with fewer than two dogs in a household are unlikely to become infected. It turns out that dogs are 14 times more effective at spreading Chagas disease than humans.

“Many of the dogs are not in good shape, they’re exposed to a whole bunch of parasites and worms and they just get scraps to eat,” Kitron says. “But the idea of just eliminating the dogs is not an option. People really care about their dogs.”

An alternative may be to identify dogs that are most at risk of remaining infectious for a long period of time. These “super spreaders” could be targeted with insecticide collars. Research is also ongoing for a vaccine against T. cruzi in mongrel dogs.

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Sewage raises West Nile virus risk

More than 700 U.S. cities have combined sewer overflows, allowing wastewater to flow into urban waterways with minimal treatment. Video of an Atlanta CSO stream by Gonzalo Vazquez-Prokopec.

Sewage that overflows into urban creeks and streams during periods of heavy rain can promote the spread of West Nile virus, an Emory study finds.

The analysis of six years of data showed that people living near creeks with sewage overflows in lower-income neighborhoods of Southeast Atlanta had a seven times higher risk for West Nile virus than the rest of the city.

“The infection rate for mosquitoes, birds and humans is strongly associated with their proximity to a creek impacted by sewage,” says Gonzalo Vazquez-Prokopec, the Emory disease ecologist who led the study. “And if the creek is in a low-income neighborhood, we found that the entire cycle of infection is even higher.”

More affluent residents are more likely to have air-conditioning and use insect repellant and other protective measures, the researchers theorized.
Red outline shows Atlanta boundary: Click on graph to enlarge.

The study, to be published by Environmental Health Perspectives, was a collaboration of Emory, the Centers for Disease Control and Prevention, the Georgia Division of Public Health, the Fulton County Department of Health and Wellness, the National Institutes of Health, the Fogarty International Center and the University of Georgia.

According to the Environmental Protection Agency, about 850 billion gallons per year of untreated mixed wastewater and storm water are discharged into U.S. urban waters, mainly through combined sewer overflow (CSO) systems that are used in more than 700 cities. Under normal conditions, CSO systems channel wastewater to a treatment plant before it is discharged into a waterway. During periods of heavy rain or snowmelt, however, the wastewater flows directly into natural waterways after only minimal chlorine treatment and sieving to remove large physical contaminants.
Photos of Atlanta CSO streams, above and below, by Gonzalo Vazquez-Prokopec.

Most of the available data on the human health impacts of sewage-affected waterways focuses on the effects of exposures to bacteria, heavy metals, hormones and other pollutants.

Previous research by Emory’s Department of Environmental Studies has shown that the Culex mosquito – a vector for West Nile virus and other human pathogens – thrives in Atlanta streams contaminated with CSO discharges. The mosquitoes become more populous, breed faster and grow larger than those found in cleaner waters.

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“We wanted to know if the CSOs also raised the risk of getting infected with West Nile Virus,” said Uriel Kitron, chair of environmental studies and a co-author of the study.

An expert in geographic information systems (GIS) technology, Vazquez-Prokopec did a spatial analysis integrating the geographic coordinates of each CSO facility and associated streams, and six years of surveillance data on mosquito abundance and West Nile virus infections in mosquitoes, humans, blue jays and crows. (These birds are considered sentinels for the disease, due to their high West Nile Virus mortality and their proximity to humans.)

During 2001-2007, Georgia reported 199 human West Nile virus infections and 17 deaths. About 25 percent of the cases resided in Fulton County. The county forms the core of metropolitan Atlanta, and encompasses a range of socio-economic conditions, from the wealthiest neighborhoods in the state to those with the highest poverty rates in the country.

The analysis found that mosquitoes and birds near all seven of the CSO facilities and associated streams of Atlanta had significantly higher rates of West Nile virus infection than those near urban creeks not affected by CSOs. Humans residing near CSO streams also had a higher rate of infection if they lived in a low-income neighborhood with a greater proportion of tree canopy cover and homes built during the 1950s-60s. Residents of a wealthy northern Fulton County area did not experience an increase in West Nile virus cases, despite their proximity to two CSO streams.

In 2008, Atlanta completed an underground reservoir system designed to reduce the size and the number of CSOs. “In terms of mosquitoes, however, this remediation has the potential to make things worse instead of better by releasing slower flows of nutrient-rich effluent into streams,” Vazquez-Prokopec notes.

Emory scientists and public health officials are continuing to study West Nile virus and CSOs in Atlanta urban streams. Their goal is to help identify effective measures to limit the spread of the disease.

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Brain expert explores realm of human dawn

The A. Sediba cranium belonged to a juvenile that lived nearly 2 million years ago. Photo by Brett Eloff, courtesy of Wits University.

Emory anthropologist Dietrich Stout has been tapped to help analyze the skull of a newly discovered hominid species, dating back to the pivotal period when the human family emerged.

“This is a remarkably intact skull of a potential human ancestor from right around two million years ago, when we think the origin of our own genus was happening,” Stout says. “It’s exciting to learn that such a thing exists, let alone to be asked to work on it.”

Stout was chosen to join the team of researchers on the project due to his expertise on early brain function, particularly the relationship between the use of stone tools and brain evolution.

"Whatever story this skull has to tell, it will be interesting," Stout says.

The fossilized skull was found last year in the Cradle of Humankind, South Africa. Paleoanthropologist Lee Berger, from the University of the Witwatersrand, and fellow researchers have since recovered skeletal remains of several other individuals belonging to the new species, named Australopithecus sediba.

Scientists estimate that the individuals lived 1.78 to 1.95 million years ago, when early species of the human genus Homo existed along with species from the more ape-like genus Australopithecus.

Attempts to narrow down the emergence of the human line have “always been a bit messy,” Dietrich says, noting that multiple candidate species have been identified – often from incomplete remains and sometimes based on a single individual. The numerous pieces emerging from the A. sediba site, however, already represent at least two individuals and are fitting together like a puzzle, giving researchers a clearer view back in time.

Sediba means “source” in Sotho, and A. sediba shows an interesting mix of characteristics. “They have primitive, ape-like long arms, but much more human-like bi-pedal legs and posture,” Stout says. “The skull looks to have the capacity for the size of brain you’d expect to find in a modern chimpanzee – or perhaps an early human ancestor. It appears to be on the cusp, giving us the potential to tease apart some of the really interesting questions about what got human brain evolution started, such as whether the size or structural changes were first.”

Stout will join other members of the team in Johannesburg and examine the fossils first hand. High-tech scans of the skull fossil are being used to create a virtual, 3-D “cast” of the cranium. “It’s not like working with an actual flesh brain, but it will give us information about the size and volume of what was inside the cranium, and some of the features of the surface morphology,” Stout says.

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Synthetic cell: A step closer to 'recipe for life'

The creation of the first self-replicating, synthetic cell by the J. Craig Venter Institute is being hailed as a milestone in the history of biology and biotechnology. In the journal Science, the researchers described the steps to make a bacterial cell controlled by a chemically synthesized genome.

“It’s marvelous what they’ve done,” says Emory chemistry chair David Lynn. “They’ve taken a major step in defining a minimal set of chemical instructions for what we call living. This understanding, and the underlying technology, will certainly be extended and amplified into a synthetic biology. Their accomplishment also moves us that critical step closer to the definition of and a recipe for life. And that is profound.”

Watch the video, above, of Lynn explaining the discovery on CNN.

Lynn, professor of biomolecular chemistry, is working to understand supramolecular self-assembly, and how life may have originated on pre-biotic Earth.

“What Craig Venter and his team have done is taken the genome out of one organism and put it into another,” Lynn says. “Our group is coming at it from the opposite direction, of emergent life forms. Both approaches are trying to define the minimal chemical composition for life.”

Excitement over Venter's discovery should be tempered by caution, says Paul Wolpe, director of the Emory Center for Ethics. "Like any great scientific innovation, this has enormous promise and enormous peril," Wolpe said on ABC World News Tonight. "This may allow us to make more virulent viruses. This could unleash a bacterium on the world that has properties we didn't expect that could cause great disease and ecological damage."

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Peptides may hold 'missing link' to life

Emory scientists have discovered that simple peptides can organize into bi-layer membranes. The finding suggests a “missing link” between the pre-biotic Earth’s chemical inventory and the organizational scaffolding essential to life.


“We’ve shown that peptides can form the kind of membranes needed to create long-range order,” says chemistry graduate student Seth Childers, lead author of the paper recently published by the German Chemical Society’s Angewandte Chemie. “What’s also interesting is that these peptide membranes may have the potential to function in a complex way, like a protein.”

Chemistry graduate student Yan Liang captured images of the peptides as they aggregated into molten globular structures, and self-assembled into bi-layer membranes. The results of that experiment were recently published by the Journal of the American Chemical Society.

“In order to form nuclei, which become the templates for growth, the peptides first repel water,” says Liang, who is now an Emory post-doctoral fellow in neuroscience. “Once the peptides form the template, we can now see how they assemble from the outer edges."

Click here to watch the movies.

In addition to providing clues to the origins of life, the findings may shed light on protein assemblies related to Alzheimer’s disease, Type 2 diabetes, and dozens of other serious ailments.

“This is a boon to our understanding of large, structural assemblies of molecules,” says Chemistry Chair David Lynn, who helped lead the effort behind both papers, which were collaborations of the departments of chemistry, biology and physics. “We’ve proved that peptides can organize as bi-layers, and we’ve generated the first, real-time imaging of the self-assembly process. We can actually watch in real-time as these nano-machines make themselves.”


Chemistry grad student Seth Childers, left, discovered that if you just add water to simple peptides, you get the scaffold for life. Fellow graduate student Yan Liang, right, made the first real-time images of the peptides self-assembling into nano-machines. Photo by Bryan Meltz.

The ability to organize things within compartments and along surfaces underpins all of biology. From the bi-layer phospholipids of cell membranes to information-rich DNA helices, self-assembling arrays define the architecture of life.

But while phospholipids and DNA are complicated molecules, peptides are composed of the simple amino acids that make up proteins. The Miller-Urey experiment demonstrated in 1953 that amino acids were likely to be present on the pre-biotic Earth, opening the question of whether simple peptides could achieve supra-molecular order.

To test how the hollow, tubular structure of peptides is organized, the researchers used specialized solid-state nuclear magnetic resonance (NMR) methods that have been developed at Emory during the past decade.


Working with Anil Mehta, a chemistry post-doctoral fellow, Childers tagged one end of peptide chains with an NMR label, and then allowed them to assemble to see if the ends would interact. The result was a bi-layer membrane with inner and outer faces and an additional, buried layer that localized functionality within the interior.

“The peptide membranes combine the long-range structure of cell membranes with the local order of enzymes,” Childers said. “Now that we understand that peptide membranes are organized locally like a protein, we want to investigate whether they can function like a protein.”

The goal is to direct molecules to perform as catalysts and create long-range order. “We’d really like to understand how to build something from the bottom up,” Childers says. “How can we take atoms and make molecules? How can we get molecules that stick together to make nano-machines that will perform specific tasks?”

The research is part of “The Center for Chemical Evolution,” a center based at Emory and Georgia Tech, for integrated research, education and public outreach focused on the chemistry that may have led to the origin of life. The National Science Foundation and the U.S. Department of Energy have funded the research.

Many groups studying the origins of life have focused on RNA, which is believed to have pre-dated living cells. But RNA is a much more complicated molecule than a peptide. “Our studies have now shown that, if you just add water, simple peptides access both the physical properties and the long-range molecular order that is critical to the origins of chemical evolution,” Childers says.

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Tiny aphids hold big surprises in genome

Pea aphids, expert survivors of the insect world, appear to lack major biological defenses, according to the first genetic analysis of their immune system.

“It’s surprising,” says Emory biologist Nicole Gerardo, who led the study, published this week in Genome Biology. "Aphids have some components of an immune system, but they are missing the genes that we thought were critical to insect immunity."

Pea aphids are major agricultural pests and also important biological models for studies of insect-plant interactions, symbiosis, virus vectoring and genetic plasticity. These resilient insects thrive despite a host of enemies, including parasitic wasps, lady bugs, fungal pathogens and frustrated farmers and gardeners the world over.


The immune-system analysis is among a group of findings generated by the International Aphid Genomics Consortium, which just published the full sequence of the pea aphid genome, and sponsored dozens of in-depth analyses of different areas of the sequence.

"This is the first look at the genome of a whole group of insects we know little about," says Gerardo, an evolutionary biologist who focuses on host-parasite interactions.

All insects previously sequenced belong to a group that undergoes metamorphosis. Pea aphids, however, belong to an insect group known as basel hemimetablous – meaning they are born looking like tiny adults.
"We went into this expecting to find the same set of immune-system genes that we've seen in the genomes of flies, mosquitoes and bees," Gerardo says. “Given these missing genes, it seems that aphids have a weak immune system. Our next step is to figure out how they protect themselves.” One hypothesis is that aphids may compensate for their lack of immune defenses by focusing on reproduction. From birth, a female aphid contains embryos that also contain embryos.

“She is born carrying her granddaughters,” Gerardo says. “In a lab, a female aphid can produce up to 20 copies of herself per day. About 10 days later, those babies will start producing their own offspring.”

Over 50 million years, aphids have evolved complex relationships with beneficial bacteria that supply them with nutrients or protect them from predators and pathogens. It’s possible that the weak immune response in aphids developed as a way to keep from killing off these beneficial microbes, Gerardo says. “A key question is whether these microbes could have changed the aphid genome, or changed how the aphid uses its genes.”

Further study of how the aphid immune system interacts with microbes could yield better methods for controlling them in agriculture.

Aphids are not just pests, Gerardo says. They are also potential resources for questions related to human health.

"Humans need beneficial bacteria for proper digestion in the gut and to protect against cavities in the teeth," she says. "Some people feel sick when they take antibiotics because the drug kills off all the beneficial bacteria. If we can study the process of how to keep beneficial bacteria while clearing out harmful bacteria across several organisms, including aphids, we might be able to understand it better."

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Biology may not be so complex after all

By Carol Clark

Centuries ago, scientists began reducing the physics of the universe into a few, key laws described by a handful of parameters. Such simple descriptions have remained elusive for complex biological systems – until now.

Emory biophysicist Ilya Nemenman has identified parameters for several biochemical networks that distill the entire behavior of these systems into simple equivalent dynamics. The discovery may hold the potential to streamline the development of drugs and diagnostic tools, by simplifying the research models.

The resulting paper, now available online, will be published in the March issue of Physical Biology.

"It appears that the details of the complexity of these biological systems don't matter, as long as some aggregate property, which we've calculated, remains the same," says Nemenman, associate professor of physics and biology. He conducted the analysis with Golan Bel and Brian Munsky of the Los Alamos National Laboratory.

The simplicity of the discovery makes it “a beautiful result,” Nemenman says. “We hope that this theoretical finding will also have practical applications.”

He cites the air molecules moving about his office: “All of the crazy interactions of these molecules hitting each other boils down to a simple behavior: An ideal gas law. You could take the painstaking route of studying the dynamics of every molecule, or you could simply measure the temperature, volume and pressure of the air in the room. The second method is clearly easier, and it gives you just as much information.”


Nemenman wanted to find similar parameters for the incredibly complex dynamics of cellular networks, involving hundreds, or even thousands, of variables among different interacting molecules. Among the key questions: What determines which features in these networks are relevant? And if they have simple equivalent dynamics, did nature choose to make them so complex in order to fulfill a specific biological function? Or is the unnecessary complexity a “fossil record” of the evolutionary heritage?

For the Physical Biology paper, Nemenman and co-authors investigated these questions in the context of a kinetic proofreading (KPR) scheme.

KPR is the mechanism a cell uses for optimal quality control as it makes protein. KPR was predicted during the 1970s and it applies to most cellular assembly processes. It involves hundreds of steps, and each step may have different parameters.

Nemenman and his colleagues wondered if the KPR scheme could be described more simply. "Our calculations confirmed that there is, in fact, a key aggregate rate," he says. "The whole behavior of the system boils down to just one parameter."

That means that, instead of painstakingly testing or measuring every rate in the process, you can predict the error and completion rate of a system by looking at a single aggregate parameter.


Charted on a graph, the aggregate behavior appears as a straight line amid a tangle of curving ones. “The larger and more complex the system gets, the more the aggregate behavior is visible,” Nemenman says. “The completion time gets simpler and simpler as the system size goes up.”

Nemenman is now collaborating with Emory theoretical biologist Rustom Antia, to see if the discovery can shed light on the processes of immune cells. In particular, they are interested in the malfunction of certain immune receptors involved in most allergic reactions.

"We may be able to simplify the model for these immune receptors from about 3,000 steps to three steps," Nemenman says. "You wouldn't need a supercomputer to test different chemical compounds on the receptors, because you don't need to simulate every single step, just the aggregate."

Just as the discovery of an ideal gas law led to the creation of engines and automobiles, Nemenman believes that such simple biochemical aggregates could drive advancements in health.

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Working through the bugs of evolution

The science blog io9.com recently paid a visit to two of the leading labs that use parasites and bugs to research evolutionary ecology. Both of the labs are in Emory's biology department, headed by Nicole Gerardo and Jaap de Roode. Check out the photo tours of their research, featured on io9.com.

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Finally, 'Noble' Prizes for animals

Emory psychologist Frans de Waal writes in the Huffington Post:

"Time has just chosen its "Man of the Year," whose intelligence was immediately questioned, so why not review some genuine, proven Einsteins, even if they are animals?

"Animals seem to be getting smarter all the time. Since 2000, discovery after discovery has put a dent in human uniqueness claims. At the start of the decade, most of us believed that only chimpanzees might come anywhere near our wonderful human intellect, but by 2010 we realize that also dogs, birds, monkeys, and elephants challenge the human-animal divide, which has begun to look like Swiss cheese."

De Waal goes on to list "10 Animal 'Noble' Prizes for Overall Smartness," topped by a juvenile chimpanzee who surpassed humans on a cognitive task. "This is my way of celebrating the end of a decade," de Waal explains, "which has been miserable in so many ways, but not for the field of animal cognition, which is on a roll!"

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Watch the video, above, on chimpanzee culture filmed at Emory's Yerkes National Primate Research Center.

Mosquito hunters invent better disease weapon

Emory researchers believe they have come up with the cheapest, most efficient way yet to monitor adult mosquitoes and the deadly diseases they carry, from malaria to dengue fever and West Nile Virus. Emory has filed a provisional patent on the Prokopack mosquito aspirator, but the inventors have provided simple instructions for how to make it in the Journal of Medical Entomology.

“This device has broad potential, not only for getting more accurate counts of mosquito populations, but for better understanding mosquito ecology,” says Gonzalo Vazquez-Prokopec, the invention’s namesake. Vazquez-Prokopec is a post-doctoral fellow working with Uriel Kitron, chair and professor of environmental studies.

“There is a great need for effective and affordable mosquito sampling methods. Use of the Prokopack can increase the coverage area, and the quality of the data received, especially for blood-fed mosquitoes. Ultimately, it can help us develop better health intervention strategies.”

In both field and lab tests, the Prokopack outperformed the current gold standard for resting mosquito surveillance – the Centers for Disease Control and Prevention Backpack Aspirator (CDC-BP). In addition to having a longer reach, enabling it to collect more mosquitoes than the CDC-BP, the Prokopack is significantly smaller, lighter, cheaper and easier to build.

Anyone with access to a hardware store, and about $45 to $70, can make the Prokopack, which uses a battery-powered motor to suck up live mosquitoes for analysis. Mosquito-borne diseases rank among the world’s top killers, and Vazquez-Prokopec hopes that more affordable and efficient surveillance methods will help save lives.

“I come from a developing country,” says the Argentine native. “I understand what it feels like to know that there is a health technology available, and to not have the money to access it.”

For decades, public health officials have struggled to conduct mosquito surveillance. One early method, with obvious drawbacks, was to expose a bit of skin and count the bites. Another low-tech method is to spray inside a home with insecticide, and gather the bugs that fall onto on a drop cloth.

Mosquito traps baited with a chemical that mimics human sweat are sometimes used to catch live adult insects. But these traps capture only females who are looking for a meal.

The CDC-BP can quickly vacuum up samples of live specimens, which can be analyzed in a lab to determine the source of blood they recently consumed. The drawbacks to the CDC-BP, however, include its heavy weight (25 pounds), its bulk and its price – about $450 to $750 in the United States.

Emory researchers used a CDC-BP in their study of West Nile Virus and urban mosquito ecology in Atlanta. They wanted to learn if mosquitoes that harbor the virus were overwintering in nooks near the ceilings of sewer tunnels. But the CDC-BP only reaches six feet, and the tunnels are 15-feet high.

With a bit of ingenuity and a few trips to the hardware store, the research team put together a solution: a plastic container, a wire screen, a plumbing pipe coupler, a battery-powered blower motor and painter extension poles. After some experimentation with these components, the Prokopack was born.

“It’s not like we woke up one day and said, ‘Let’s invent a mosquito aspirator,’” Vazquez-Prokopec explains. “It grew out of our needs during field research.”

Comparative tests with the Prokopack and the CDC-BP were conducted outdoors and in sewer tunnels during the Emory lab’s Atlanta research projects. Additional field tests were done during a dengue fever study in Iquitos, Peru, where public health technicians are trying to control mosquitoes in homes. The Prokopack, which weighs less than two pounds, collected more mosquitoes than the CDC-BP, and reached higher into ceilings and into foliage.

Collecting more mosquitoes in higher locations can give researchers more insights into their behaviors. Upper foliage, for instance, can yield more mosquitoes resting after feeding on birds. And upper walls and ceilings of homes may harbor more mosquitoes resting after a meal on humans.

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