Spring 2011 Issue by Carolina Scientific

Carolina Scientific

carolina

sc1ent1fic Undergraduate Magazine

Spring 2011

UNC-Chapel Hill

Volume III, Issue II

Spring 2011, Volume III Issue II Copyright ÂŠ 2004 Richard Ling

Carolina Scientific

Mission Statement: Founded in Spring 2008, Carolina Scientific serves to educate undergraduates by focusing on the exciting innovations in science and current research that are taking place at UNC-CH. Carolina Scientific strives to provide a way for students to discover and express their knowledge of new scientific advances, to encourage students to explore and report on the latest scientific research at UNC-CH, and educate and inform readers while promoting interest in science and research.

From the Editors: This year, we are thrilled to be a part of Carolina Scientific’s new leadership, passed on to us from the former editors and founders of the magazine. We have watched it grow from an idea into a full-fledged publication, and we hope you find that we’ve carried on Carolina Scientific’s mission statement to the fullest—to provide an interesting and informative collection of campus-wide research. We have enjoyed watching our staff tackle challenging scientific material, and hope that their passion for research and science shines through in their pieces. Enjoy! Rebecca S., Garrick, Rebecca H., and Rohan (From left to right) Rebecca Searles, Editor-in-Chief and Biology Editor, is a senior Biology and Psychology double major. Garrick Talmage, Chemistry Editor, is a junior Biochemistry major and Biology and Math minor. Rebecca Holmes, Physics Editor, is a senior Physics major. Rohan Shah, Production Editor, is a senior Biology major and Chemistry minor.

Special thanks to our 2011 Carolina Scientific Production Staff! (From left to right) Janitra Venkatesan Kati Moore Kristen Rosano Hema Chagarlamudi Contact us at carolina_scientific@unc.edu.

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Table of Contents 4

When Smaller is Better: Human Immune System Studies in Mice Darya Gakh

6 8 10

It All Comes Down to Sweat Doug Lange Heating Up the Evolution Debate Hetali Lodaya Thirty-Two Bottles of Coke and Twenty Feet of Intestine Kara Stout

Some Like It Hot: Extreme Microbes in the Guaymas Basin Kelly Speare

14 16

The Coral Conundrum Kelsey Ellis

A Synthetic Substitute Delivers More Than Blood Kristen Rosano Plant Organ Donation: Shedding for a Good Cause Lindsay Ross The Mystery Of The Deep: Inside The Plume Maggie Hunter

22 24

Antibiotics Making a Comeback Nabila Sarki Thinking Positively About Restoration And Conservation in Aquatic Communities Patrick Fox

Cutting Carbs Just Won’t Cut It: Investigating the Influence of Genetics on Metabolic Function Kristine Chambers

28 30 32

The Secret to Skunking Connie Wang

The Greater Meaning of Global Warming Kati Moore

34 36

Mind-Body Interdependencies “Positively” Influence Well-Being Jana Lembke The Physicist’s Playground Matt Dutra The Game of Telephone and An Analysis of Signal Detection in Animals Madison Roche

Astronomical Kingdom Apurva Oza

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Carolina Scientific

When Smaller Is Better:

Human Immune System Studies in Mice

Darya Gakh, Staff Writer

hey eat your cheese. They scare your elephants. Usually found in bundles of four or more, mice are clean creatures despite their reputation [1]. Better yet, they may help provide the cure to human diseases such as Hepatits B Virus (HBV), Hepatitis C Virus (HCV), and even Human Immunodeficiency Virus (HIV). Not so scary after all. Lishan Suâ&#x20AC;&#x2122;s lab is the first to use mice to develop a small animal model with a human immune system for

available. HCV generally starts out in an acute stage, during which symptoms resemble the flu. However, in most cases this acute stage progresses into a chronic stage, whereupon it has been present in the body for over six months. Over 175 million people are chronically infected by HCV, often resulting in hepatitis, liver fibrosis, cirrhosis and development of hepatocellular carcinoma [3]. Chloe Greguska, a junior biology major at the University of North Carolina, is helping optimize the

Figure 1. Approximately 99 percent of human genes have counterparts in the mouse. Out of the 30,000 genes in both the mouse and human genomes, only about 300 are unique to either.

studies of HBV and HCV [2]. HCV is an infectious disease that affects the liver through reoccurring infections that cause scarring of this tissue. It is estimated that 270-300 million people worldwide are infected with HCV, and no vaccine is currently

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study of HCV on these mouse models. In order to give these immunodeficient animal models human immune systems, the mice must first be made liver deficient. This is done by killing their liver cells by expressing the FK506 binding protein under control

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Though frightening for some, the common house mouse, mus musculus, has one of the most valuable genomes for human disease research.

of the albumin promoter (AFC8) and then injecting human liver stem cells into the mice [3]. This has finally proven successful and is detailed in a paper recently published by the team. The Su lab is working toward understanding how these diseases interact with the immune system. In order to do this, they are infecting the mice models with HCV, and then taking blood samples to examine how the human immune cells have responded to HCV infection. It is important to note that, while this procedure puts human cells into the mouse, only about 20 percent of the cells in the chimeric liver are human. After taking blood samples, the number of mouse cells and human cells is counted and then the human cells are used for further analysis [4]. One of the projects that Chloe Greguska is working on attempts to improve the 20 percent reconstitution rate. This is done using several methods, one of which involves using oncogenes. Oncogenes are genes which can cause cells undergoing apoptosis, programmed cell death, to survive and grow instead. The use of these oncogenes can frequently lead to cancer, causing difficulties for HCV infection. However, this allows for the possibility of liver cancer research, another area of research the Su lab hopes to work on. The Su lab also examines HIV. Through the use of the mouse model, they are working on being able to examine how HIV infection leads to immunodeficiency or AIDS. Furthermore, the Su lab is simultaneously working to see how HIV and HCV co-infect cells. It has been found that when HCV and HIV infect patients simultaneously, the liver disease progresses very rapidly. For the first time, there is a mouse model that can simulate the co-infection of these diseases [5].

Su says that one of the most interesting things he found in his research is the â&#x20AC;&#x153;ability to manipulate the human immune system in human stem cell development and the ability to generate any human tissue in immune deficient miceâ&#x20AC;? [5]. Further studies can look into how human viruses can be transmitted to these mice models and how the mouseâ&#x20AC;&#x2122;s human immune system will react to this. These little creatures hold the key to examining immune system responses in prevalent human diseases. So next time you see a mouse in your house, give it some cheese and avoid the mouse traps, because it may someday save your life [6].

Darya Gakh is a junior Biochemistry major and Spanish minor.

References

1. Interview with Lishan Su, Ph.D. 02/11/11 2. Bruno S, Facciotto C. Ann Hepatol 2008;7:114-9 3. Su, Lishan, et al. Gastroenterology. 2011 4. Interview with Chloe Greguska. 02/12/11

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It All Comes Down to Sweat Doug Lange, Staff Writer

weat is just a foul-smelling annoyance to most people, a regulatory body-function that we put up with day-to-day. But if youâ&#x20AC;&#x2122;re the parent of a baby that just came up positive on a newborn screening test for cystic fibrosis (CF), sweat just got a lot more important. CF is a genetic disorder that affects about 2500 newborns every year in the USA. CF is caused by a mutation in the gene for CFTR, a protein that acts primarily as a channel for chloride to flow through. People with CF excrete abnormally large amounts of chlorine and sodium in their sweat [1]. This is the

basis for sweat tests performed on newborns to examine for increased salt concentration. CF is a serious disorder, so early diagnosis is crucial in order to allow patients to receive treatment as soon as possible. Because of this, Dr. Vicky LeGrys, faculty member of the division of Clinical Laboratory Science at UNC, has been researching ways to decrease erroneous results obtained by sweat tests. She has worked with national and international committees to establish written standards for sweat testing and has implemented proficiency testing in laboratories. Recently, LeGrys obtained records from the

from Johns Hopkins CF center website.

Figure 1. A pediatrician administers a cystic fibrosis sweat test to a baby. Dr. Vicky LeGrys of the Clinical Laboratory Science division at UNC studies the reliability of these tests.

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From the University of Utah cystic fibrosis webpage.

Wikipedia commons, posted on March 10, 2009 by donabelsdsu.bot

Figure 2. Computer representation of CFTR gene.

Figure 3. Illustration of 2 CFTR proteins.

115 labs in the country that are accredited by the CF Foundation to offer sweat tests and examined the percentage of tests that yielded an insufficient volume of sweat for analysis, an indication for performance. From this data LeGrys learned two important things about the sweat test: the method for collecting the sweat did not affect the number of insufficient tests and there was a huge variability in the percentage of insufficient tests across CF centers, ranging from 0-40%. This large range on a relatively constant population was collection method independent and allowed LeGrys to infer that the variability was related to operator error in the laboratory [2]. LeGrys used this data to set a benchmark for performance for quality improvement. Laboratories should achieve a sufficient volume for testing more than 90% of the time in patients less than 3 months of age [2]. â&#x20AC;&#x153;You are confirming the diagnosis of a lethal disease. Therefore it is of the utmost importance it is done as accurately as possible,â&#x20AC;? says LeGrys. All 115 labs are monitored annually and are visited every 5 years to make sure they remain in compliance with written laboratory standards. Dr. LeGrys frequently visits clinical laboratories nationwide and internationally to evaluate operator performance of the sweat test and to develop quality improvement initiatives [2].

CF may be a fatal illness, but thanks to modern medicine and early treatment the average life span of CF patients is steadily increasing. Sure, sweat might not seem important to most of us from day to day, but to some it all comes down to sweat.

Doug Lange is a junior Clinical Laboratory Science major.

References

1. D. Zieve, et al. Cystic Fibrosis. 2010, 5, 101. 2. Interview with Dr. Vicky LeGrys, Ph.D. 02/21/10.

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Heating Up the Evolution Debate Hetali Lodaya, Staff Writer

t is a simple debate that has raged for centuries: creation or evolution? A common creationist argument centers on the time required for life to evolve. The world has simply not been around long enough, creationists argue, for simple bacteria to evolve into complex life forms like humans without the help of a creator [1]. In addition, many essential biological reactions as they are understood today cannot progress properly without the help of a catalyst — it would take significant amounts of time, creationists say, for these catalysts to become widespread. Understanding this problem requires looking at rates of reactions and temperatures at which they occur, especially when the reactions are uncatalyzed. It is likely that many of the reactions integral to the development of life originally occurred without the help of enzymes, resulting in slow rates overall until appropriate enzyme catalysts evolved. The general ‘rule of thumb’ for chemists is that a 10° C increase in temperature will double a reaction rate [2]. Under this assumption, even a very warm primordial earth would have had little effect on reactions whose uncatalyzed half-lives are, in some cases, millions of years. The Wolfenden group at UNC-Chapel Hill recently published research on slow reactions that challenges this assumption [3]. Reaction rates were measured and extrapolated for several biological processes

Figure 1 used with the permission of Dr. Wolfenden.

Figure 1. Projected change in rate for an enzyme that lowers entropy of activation, TΔS (left) versus one that lowers enthalpy of activation, ΔH (right).

that, uncatalyzed, take very long to progress. According to the established chemical theory, a temperature change from 25 °C to 100 °C, for instance, should cause about a 70-fold increase in rate for a typical reaction. This prediction is based on the iodine clock reaction, and can be found in chemistry textbooks and lab manuals across the world. As shown in Table 1, almost all of the biological reactions studied were found to experience much greater increases in rate than the iodine clock reaction with this same temperature change. It is also important to note that the slowest reactions experienced the greatest increase in rate. This creates a levUsed with the permission of Dr. Wolfenden. eling effect—reactions that Table 1. Temperature effects on the rates of reactions without catalysts. As half-lives are slow experience greater increase, the ratio of equilibrium constants k100° and k25° increases, showing that the gains in speed with temsame increase in temperature will increase the rate of a slow reaction much more perature, allowing them to than the rate of a fast reaction. ‘keep up’ with fast reactions.

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Carolina Scientific wet early Earth where biological reactions occurred unassisted, sped up by the temperature of their surroundings. As the Earth cooled, catalysts slowly evolved that worked faster and faster despite the decrease in temperature, maintaining a pace that explains the speed with which life forms became more complex [3]. “Physical organic chemistry is what it is, and the possibility that it has implications for evolution is wonderful, and startling,” Credit: By P. Carrara, NPS [Public domain], via Wikimedia Commons states Professor WolfenFigure 2. Fossilized evidence of stromatolites from about 1 billion years ago. den [4]. The creationevolution debate is far These reaction rates collapse the time needed for from over, but the Wolfenden work on the relationlife to evolve even on a slightly warmer primordial ship between temperature and reaction rates throws Earth by as much as five orders of magnitude—aca new piece of evidence into the primordial mix. cording to Professor Wolfenden, “it is a new way of looking at the early evolution of life.” [4] Additional evidence comes from the group’s study of several proto-enzymes, small molecules that probably evolved to become the first biological catalysts. A rate can be increased by either changing the enthalpy of activation, ΔH, or entropy of activation, TΔS. As shown in Figure 1, only a catalyst that affected ΔH would have a significant effect on rate—the rate change is much more pronounced for these catalysts as k changes. Proto-enzymes were studied to understand which pathway they use to increase reaction rate; the group’s results strongly Hetali Lodaya is a suggest that they all use the enthalpic mechanism. freshman BiochemisUnder this model, rate enhancement actually intry major. creases as temperature decreases (Figure 1). Essentially, the compounds believed to be nature’s earliest catalysts actually function better at lower temperatures. This suggests that as the Earth cooled, these References enzymes flourished and were evolutionarily favored. 1. Ball, Phillip. Some Like it Hot. 2010, <http://www.nature. Geological evidence indicates that life appeared com/news/2010/081110/full/news.2010.590.html>. on Earth almost as soon as the oceans were formed, 2. Chin, Gilbert. 2011, <http://www.sciencemag.org/ but scientists have yet to unravel the mystery of ex- content/331/6013/11.4.full>. 3. Stockbridge et al. Proc. Natl Acad. Sci. 2010, 107, 22102actly what events led to life as we know it today. The 22105. Wolfenden group’s findings lend support to a hot, 4. Interview with Richard Wolfenden, Ph.D., 02/09/11.

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Thirty-two Bottles of Coke and Twenty Feet of Intestine

Kara Stout, Staff Writer

very day 11.5 liters of ingested food and digestive juices pass through the digestive systemâ&#x20AC;&#x201D;the equivalent of over 32 bottles of coke [1]. Food is passed through the 20 feet of small intestine that connects the stomach to the colon, which will complete more than 90% of the digestion and absorption using bile and pancreatic juices (Figure 1)[2]. Every four days the epithelial lining is completely replaced due to damage caused by the chemical and mechanical abuse of the contents it is digesting [3]. A growing area of research that I am involved in is the study of the intestinal stem cells (ISCs) that replenish the damaged epithelial lining. The small intestine is divided into the three regions based upon their proximity to the stomach: the duodenum, jejunum, and ileum (Figure 1). However, the fundamental unit of the small intestine is the crypt-villus axis (Figure 2). Villi are cellular projections into the intestinal lumen that provide an increased surface area available for digestion. Between the villi are invaginations called the crypts of Lieberkuhn, which are covered in epithelial cells. At the base of the crypts are the ISCs, which are constantly dividing to replenish cells in the crypt. ISCs produce four types of cells: enterocytes, which aid in digestion and absorption, goblet cells that secrete mucin which forms mucus, enteroendocrine

Figure 1. Basic anatomy of the digestive tract.

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Figure 2. Crypt-Villus axis labeling the 4 primary cell types in the intestinal epithelium.

cells, which secrete hormones important to the gastrointestinal system, and Paneth cells that defend against microbes [3]. These cells continue to divide as they mature and migrate up the villi (Figure 2). Dr. Henning at UNC-Chapel Hill wants to identify and isolate ISCs based on specific markers on the surface of cells. This separation is done through a process called fluorescence-activated cell sorting (FACS), where particular cells are isolated based upon the fluorescence and light scattering ability of each cell [4]. Antibodies against certain cell markers are conjugated to small fluorescent molecules, and cells are stained with a cocktail of different fluorescent antibodies. CD24, a membrane protein, is a good candidate to be a stem cell marker, and its presence has been confirmed in the crypt base by an immunohistochemical staining with the CD24 antibody (Figure 3). CD24 functions in cell-cell and cell-matrix adhesion as well as extracellular-to-intracellular signal transduction. Because of this adhesive characteristic, CD24 may be key to anchoring ISCs into the base of the crypt. To isolate CD24+ stem cells from other cells during FACS, an anti-CD45 antibody was used to exclude hematopoietic stem cells, which produce all of

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Figure 3. Mouse jejunum stained with CD24 antibody at low (A) and high (B) power.

the blood cell types. To confirm the CD24+CD45allotment was indeed stem cells (Figure 4), other accepted stem cell markers, Lgr5 and Bmi1 were used [4]. This population showed a 40-fold enrichment of the marker Lgr5 and 5-fold enrichment of Bmi1, indicating the presence of stem cells [4]. I am researching the therapeutic potential of these

isolated stem cells in the base of the crypt to replenish the four cell types located in the intestinal epithelium. Intestinal stem cells may have significant potential in the treatment of gastrointestinal disorders. They could be used to regenerate function in the small intestine inhibited in diseases such as short bowel syndrome, inflammatory bowel disease, or following irradiation. Kara Stout is a junior Biology and Global Studies major, and Mandarin Chinese minor.

References

Figure 4. Flow cytometric identification of the CD24+CD45- gated fraction in the circled region, indicating the presence of stem cells in this population of jejunal epithelium.

1. Digestive System Function Facts. 2011. <http://library. thinkquest.org/J0112205/ interesting_facts.htm>. 2. The Human Intestines: Function, Body Location, Shape, Definition, and Disease. 2011. <.http://www.mamashealth. com/organs/intestine.asp>. 3. A. Shaker, et al. Translational Res. 2010, 3, 180-187. 4. R. Furstenberg, et al. Am. J Physiol. Gastrointest. Liver Physiol. 2010. 5. Stem Cell Basics. 2009. <http://stemcells.nih.gov/info/ basics/basics6.asp>.

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Some Like it Hot: Extreme Microbes in the Guaymas Basin Kelly Speare, Staff Writer

fter an hour-long descent huddled in a frigid 3-man vessel, headlights illuminate a foreign deep-sea world out of the pitchdark water. Scientists aboard the Alvin submersible

esize about the possible origins of life on earth [2]. The Guaymas Basin in the Gulf of California (Figure 1) is situated on an area of transform faults, created by the separation of the Pacific and North American tectonic plates. However, Guaymas is unique from other spreading centers, because it experiences high rates of sedimentation that blanket the seafloor, preventing volcanic activity that is characteristic of most spreading centers [1,3,4]. As the Earth’s crust separates, seawater seeps down into crevices, is hydrothermally heated, and forced back up through hundreds of meters of organic-rich sediment, creating a variety of hot-water vents [4]. These hydrothermal vents supply the seafloor with a hot-water cocktail, rich in dissolved gasses such as methane, carbon dioxide, and hydrogen sulfide. Chemosynthetic organisms from all three domains of life, Bacteria, Archaea, and Eukarya, utilize this harsh, but chemi-

PC: L.G. Alvarez, et al. Boletín De La Sociedad Gológica Mexicana. 2009, 61, 129-141.

Figure 1. A map of the Guaymas Basin, which is a unique spreading center situated between mainland Mexico and the Gulf of California.

journey over 2,000 meters down to the seafloor to study the otherworldly home of extreme microbial communities in the Guaymas Basin. Dr. Barbara MacGregor and collaborators from the Department of Marine Sciences study a unique system of hydrothermal vents that provide an energy source for microorganisms in this otherwise desolate and uninhabitable environment [1]. Understanding hydrothermal vent systems is important to the study of microbiology, because they provide a way to hypoth-

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Photo courtesy of http://4dgeo.whoi.edu/alvin.

Figure 2. The robotic arm of the Alvin submersible taking a temperature reading in a mat of orange, yellow, and white Beggiatoa.

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Photo courtesy of Tingting Yang.

Figure 3. The Alvin submersible being lowered into the water off the deck of the Research Vessel Atlantis.

cally rich environment [4]. Additionally, petroleum production is catalyzed by the combination of heat and organic-rich sediments, creating small pockets of petroleum that seep up through the sediment [3]. Microbes living in Guaymas sediments have two forms of energy sources to choose from: organic compounds in the sediment that are derived from photosynthetic production such as petroleum, or hydrothermally processed compounds [3]. Dr. Barbara MacGregor and other scientists from the Department of Marine Sciences are studying the microbial community in the Guaymas sediment in an effort to determine what these microbes use as their carbon source, and how they interact with these hydrothermal processes. Dr. MacGregor traveled to the Guaymas Basin in 2008 and 2009 to collect sediment samples using the Alvin submersible (Figure 3). Particularly interesting are the brightly-colored giant bacteria, Beggiatoa, that grow in filamentous mats which highlight areas of hydrothermal activity (Figure 2). These enormous, yellow, orange, or white, sulfide-oxidizing bacteria

live atop sediment that is home to communities of bacteria and archaea. Beggiatoa only live on the surface of the sediment because they require oxygen to oxidize sulfide. However, microbes living in the anoxic sediment are able to metabolize anaerobically [3]. These microbes produce dissolved gasses such as methane metabolically, in addition to the natural production of gasses in the hydrothermal system [3]. Dr. MacGregor is using stable carbon isotope ratios to trace the flow of carbon through the hydrothermal system, in order to determine what the microbes are using as their carbon source. RNA provides a unique way to study carbon flow, because it can be used to link the identity of an organism to its carbon source. The carbon signature of the substrate that the microbes are metabolizing should be reflected in the stable carbon isotope ratio of their RNA [3]. As scientists gain a better understanding of microbial hydrothermal vent communities and how they derive their energy, they are better able to hypothesize about early life on earth [2]. To visit extreme microbial habitats such as the Guaymas Basin, scientists must climb into a state-of-the-art submersible able to withstand the severe temperature and pressure changes when traveling to the deep. However, microbes such as Beggiatoa thrive here; their adaptations to the unique Guaymas Basin environment are fascinating to scientists and invaluable to the field of microbiology.

Kelly Speare is a sophomore Biology major and Marine Sciences minor. References

1. Dive and Discover. 2011, <http://www.divediscover.whoi. edu/expedition1/index.html>. 2. W. Martin, et al. Nature Reviews Microbiology. 2008, 805. 3. Interview with Dr. Barbara MacGregor, Ph.D, 2/13/10. 4. A.P. Teske, et al. Appl Environ Microbiol. 2002. 68(4): 1994â&#x20AC;&#x201C;2007

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THE CORAL CONUNDRUM Kelsey Ellis, Staff Writer

oral reefs are notoriously delicate ecosystems, easily affected by climate change, ocean warming, nutrient and sediment pollution, and overfishing [1]. In the twenty-first century, their fragility has become a symbol for the environmental degradation created by our overuse of natural resources. In recent years coral reef scientists interested in reef conservation have studied the effects of these anthropogenic changes on reefs. One of these scientists, Dr. John Bruno of the Marine Sciences department, has collaborated with other researchers to study a widespread reef phenomenon: the transition of a human-disturbed reef from

Source: rling.com, Richard Ling.

Figure 1. Coral reefs like this one, located in the Great Barrier Reef, are becoming increasingly rare as the impact of humans on the ocean increases.

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Source: U.S Fish and Wildlife Service WO-3540 CD42A, author Jerry Reid

Figure 2. An example of a coral-dominated reef.

traditional coral dominance to macroalgal dominance. Through observation and analysis of case studies, Dr. Bruno has developed an explanation for these changes that holds implications for the way coral reef conservation is will be approached in the future. Many of the world’s coral reefs have been completely altered within our lifetimes. Back in the 1970’s, Dr. Bruno remembers “snorkeling on relatively pristine reefs with big golden fields of coral and hammerhead sharks circling and…it was just fantastic” [1]. But in the intervening years, many coral reefs have experienced large increases in algae growth and in some cases have become algae-dominated [2]. What Dr. Bruno has been researching is whether these changes represent an environmental phase shift or are alternative stable states for the ecosystem. A phase shift occurs in response to a change in an environmental variable and results in the ecosystem favoring a different kind of organism, in this case macroalgae over coral. An alternative stable state, on the other hand, is a biological community that has been completely changed by an outside disturbance [2]. At first glance these concepts might seem similar, but the point of Dr. Bruno’s research has been to reiterate the subtle but important differences between

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Source: http://disc.sci.gsfc.nasa.gov/oceancolor/additional/science-focus/ocean-color/bad_ bloom.shtml

Figure 3. The dominance of hard and soft corals in a healthy reef is ensured in part by algae-eating organisms such as certain kinds of fish.

phase shifts and alternative stable states in coral reefs. While a phase shift in a community can be reversed if the environmental variable that caused the shift in the first place is removed or changed, a community in an alternative stable state becomes locked in place by a series of positive feedbacks [1]. The prevailing viewpoint in coral reef ecology has been to see the change towards macroalgal domination as an alternative stable state, but Dr. Brunoâ&#x20AC;&#x2122;s research challenges this theory. To determine the nature of the macroalgal invasion, Dr. Bruno and his colleagues examined case studies that had previously been proffered as examples of coral reef alternative stable states. Data from reefs off the coasts of Australia, Jamaica, Panama, and Hawaii where the reefs became macroalgae-dominated was gathered and analyzed.

What Dr. Bruno found was that, though reefs become microalgal in response to disturbances in climate, ocean temperature, pollution, and overfishing, these changes reversed themselves in the absence of the environmental variable that triggered them [2]. This led Dr. Bruno to conclude that for the most part, the macroalgal domination of reefs represents a phase shift rather than an alternative stable state. This is an important realization because, as Dr. Bruno stated, â&#x20AC;&#x153;we need to know what has caused the change in order to be able to address itâ&#x20AC;? [1]. The discovery that the macroalgae invasion is a phase shift is a hopeful one, since it means that reefs can be restored to their former states by removing the chronic stresses that put them there in the first place. Unfortunately, because of the increasing pressures being put on coral reef ecosystems by human activities, this is no simple task. What Dr. Bruno and his colleagues propose in light of this new information is to focus on figuring out what variables killed the coral in the first place, and to take steps towards coral restoration through the reintroduction of overfished marine herbivores that eat macroalgae [2]. Thanks to his research, we now have a better understanding of the mechanisms that lead to reef degradation. Whether we choose to invest in the continued research and conservation efforts that could reverse these phase shifts in the face of continued climate change and increasing human population density remains to be seen.

Kelsey Ellis is a sophomore Environmental Science major. References Source: http://disc.sci.gsfc.nasa.gov/oceancolor/additional/science-focus/ocean-color/bad_bloom.shtml

Figure 4. A macroalgae-dominated reef.

1. Interview with John F. Bruno, Ph.D. 02/14/11. 2. J. Bruno, et al. Marine Ecology Progress Series. 2010, 413, 201-216.

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A Synthetic Substitute Delivers More than Blood Kristen Rosano, Staff Writer

ynthetic organs seem to be the next big idea in medicine. But researchers are beginning to realize they might be able to make something smaller: synthetic cells. For example, machinemade red blood cells could be the answer to problems ranging from blood shortages to chemotherapy drug delivery. This new technology is nearing reality thanks to the research of Timothy Merkel, a Chemistry graduate student in Dr. Joseph DeSimone’s laboratory [1]. Previous advances in this field have yielded particles similar to red blood cells, but ones that are quickly removed by the small blood vessels in the lungs [2]. Merkel improved synthetic blood cell technology by creating red blood cell mimics (RBCMs), porous and flexible particles that behave like red blood cells and have significantly longer lifetimes than their predecessors (Figure 2). Although synthetic blood could be important in supplying blood to trauma or surgery patients, it also has the potential to improve drug delivery, early cancer detection, and cholesterol treatments [1]. Currently, chemotherapy drugs are given in as high a dose as the liver can tolerate. RBCMs are able to change their shape in order to squeeze through

small spaces and then spring back to their original form, largely avoiding the liver. This gives them the potential to carry more chemotherapeutic agents to cancerous sites without damaging the liver. RBCMs could also detect biomarkers in the blood that indicate the presence of cancerous cells. The next generation of these porous particles is designed to capture DNA and RNA normally destroyed by nucleases, allowing medical researchers to comb the nucleic acids for biomarkers that may point to cancer at an earlier stage than traditional detection methods. Similarly, RBCMs could absorb cholesterol because of their porosity and remove it from the body when the particles are filtered out by the spleen. It all started with PRINT (Figure 1), a technology developed by DeSimone’s lab that can produce nanoparticles with control over their size, shape, and chemistry [3]. To make PRINT particles, a hydrogel (a gel-like substance that swells in water) is poured into a mold, solidified by shining light on it, and allowed to swell by hydration [1]. Merkel described the mold as a “nanoscale ice cube tray” with wells of any size and shape. Using this technique, they were able to make PRINT particles with the

Figure 1. The PRINT technique [1].

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Image credit: www.unc.edu.

Figure 2. Picture of RBCMs taken by fluorescent microscope [1].

same size, shape, and flexibility as red blood cells, calling them RBCMs. The similar morphology of RBCMs to red blood cells allows them to squeeze through tiny pores and stay in the circulatory system thirty times longer than the original synthetic cells, which are stiffer [3]. As Merkel explained, “this study was a big step towards making a plastic particle behave like a red blood cell, which could be essential to making a blood substitute happen” [1]. In vitro and in vivo tests of the particles’ abilities revealed the extent of their similarity to their natural cousins [2]. The RBCMs were able to squeeze through a channel narrower than their usual width and then relax back to their original shape. The RBCMs were also injected into mice to observe how they travel through the vasculature of a mouse’s ear. The particles appear to leave the bloodstream and enter tissues in a predictable manner over time. Although these cell mimics cannot yet transport oxygen, they are very close to having applications in a wide range of medical fields. RBCMs already seem to be good candidates for

treating splenic disorders because of their tendency to congregate in the spleen, but future research could illuminate how these drug-carrying particles could be directed toward other organs. Organ-specific targeting would improve medical treatments by eliminating the adverse effects of these drugs on the rest of the body. Future research studies will also investigate how the RBCMs could be made to selectively soak up cholesterol in order to remove it from the system. And if the particles could be made to carry oxygen, they could be used as a blood substitute, a potentially groundbreaking advance in the world of medicine.

Kristen Rosano is a freshman Biology major.

References

1. Interview with Timothy J. Merkel, 2/11/11. 2. T. Merkel, et al. PNAS. 2011, 108, 586-591. 3. Synthetic blood: research pushes nanomedicine forward. 2011, <http://www.unc.edu/spotlight/synthetic_blood>.

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Plant Organ Donation Shedding For a Good Cause Lindsay Ross, Staff Writer

armers have a mission to feed the world. To have successful harvests, they need to maximize the productivity of their crop plants. One feature of plants that growers would benefit from controlling is the shedding of fruit, seeds, flowers and leaves. This shedding process, called abscission, is a natural part of a plant’s life cycle, and the ability to either prevent or induce shedding could boost crop yield [2]. Research by biologist Sarah Liljegren and her lab team is focused on understanding the molecular basis of abscission events. Abscission, or organ separation, happens through the transport and secretion of certain enzymes into the extracellular space. These enzymes alter the surrounding cell walls and dissolve the middle lamel-

steps involved in the process. Recently, the Liljegren lab has identified two molecules that control abscission produced by the NEVERSHED and EVERSHED genes [1,2]. They uncovered NEVERSHED using a mutant screen in which many wild-type, or, normal Arabidopsis plants, were exposed to a mutagen (something known to cause changes and defects in DNA). In the offspring of these plants, Dr. Liljegren and her team looked for plants with abnormal abscission, and found a set of plants in which abscission never occurred [3]. Dr. Liljegren then located the DNA mutations in these mutants and found them to be within a single gene, which was named NEVERSHED [2]. Next, her lab used microscopy to

Figure 1. Mutations in EVERSHED restore the independent identities of the Golgi (g) and trans-Golgi network (t) in NEVERSHED mutant flowers.

la—the ‘glue’ that holds plant cells together [2]. The Liljegren lab studies these processes in Arabidopsis plants because they are small, easy to maintain, and can go from seed to seed in only six weeks. For these reasons, Arabidopsis is a common model for plant research. According to Dr. Liljegren, “it is important in the development of Arabidopsis, and other plants, that abscission occurs at the right time, is restricted to specific regions, and that protective scar tissue develops after abscission occurs [3].” Plants are expected to have a large suite of molecules which control, direct, and enact the various

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investigate the processes occurring in the cells of these mutants [3]. They discovered that the shape of the Golgi apparatus, part of the cell responsible for packing molecules to secrete, was changed (see Figure 1). In addition, the trans-Golgi network, an independent packing station in the cell, was missing in NEVERSHED mutants. The prediction is that molecules needed for abscission are not transported or secreted in Arabidopsis plants with NEVERSHED mutations [2]. To locate other genes involved in organ shedding, the Liljegren lab conducted another mutant screen

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Figure 2. EVERSHED may inhibit organ shedding by removing the HAESA and HAESA-LIKE2 receptors from the cell surface.

using the mutant nevershed plants as the starting point. They looked for offspring of these mutants that had regained abscission [3]. In these new double mutants, the Liljegren lab found a mutation in a gene they termed EVERSHED. These plants have a normal Golgi apparatus and an independent trans-Golgi network (Figure 1). Their investigations suggest that EVERSHED is involved in regulating the timing and region of abscission [1]. The product of the EVERSHED gene is a receptor-like kinase, which is a type of molecule known to bind and modulate the activity of transmembrane receptors in plants [3]. EVERSHED may bind the HAESA and HAESA-LIKE2 receptors (which are required to activate abscission [5]) and pull them back into the cell, thus preventing them from receiving signals which would otherwise begin the shedding process (Figure 2). In the nevershed evershed double mutant, it seems the signals to shed may be turned on early and stay on longer. Although evershed mutants look the same as wild-type plants, they have found that other kinases such as SERK1 also affect the timing and spatial definition of abscission [6]. Recently, the Liljegren lab has uncovered another gene, CAST AWAY, that inhibits the shedding process. They are currently characterizing the binding of CAST AWAY, EVERSHED and SERK1 to HAESA, and looking at the broader functions of NEVERSHED in regulating the movement of

molecules during plant development. In conjunction with labs in Missouri, Norway, Wisconsin, England, and Florida, Dr. Liljegren and her lab are working towards a more complete understanding of organ shedding [3]. They are hopeful that the implications of their research will be broad-reachingâ&#x20AC;&#x201D;from understanding the complex mechanisms that control the activity of plant receptors to the development of more sophisticated farming techniques.

Lindsay Ross is a junior Biology and Political Science double major and Chemistry minor.

References

1. M.E. Leslie, et al. Development. 2010, 137, 467-476. 2 S.J. Liljegren, et al. Development. 2009, 136, 1909-1918. 3 Interview with Sarah J Liljegren, PhD. 2/11/2011 4 C. Viotti, et al. Plant Cell. 2010, 22, 1344-1357. 5 S.K. Cho et al. PNAS. 2008, 105, 15629-15634. 6 M.W. Lewis, et al. Plant Journal. 2010, 62, 817-828.

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Carolina Scientific

The Mystery of the Deep: Inside the Plume Maggie Hunter, Staff Writer

n April 20, 2010, the Deepwater Horizon drilling rig exploded, pouring an estimated four to five million barrels of oil into the Gulf of Mexico, until it was capped nearly three months

Photo courtesy of Kelly Speare.

Figure 1. “Ground Zero,” the site of the Deepwater Horizon explosion.

later. This spill has become infamous as one of the biggest man-made natural disasters in history [1]. The media coverage of the spill focused mostly on the negative impact it had on the coastal systems—news networks interviewed angry fishermen and showed clips of shorebirds with their feathers drenched in slimy oil. What was largely ignored, though, is the drastic effect that the spill has had on the microbial populations that live in deep, open water. Since the spill first occurred, Dr. Andreas Teske’s marine science lab has been working busily to investigate what is happening in the world of organisms that are too small to see, but are too important to ignore. What is especially interesting about the Gulf spill is the presence of plumes, which are concentrations of tiny oil aggregates that are found deep in the water column of the ocean. The plumes were likely formed when chemical dispersants were spread on the oil slick on the surface of the ocean,

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causing it to bead together and sink. There is argument about whether or not the use of dispersants has been a true “mitigation” technique, or, if by trapping the oil under the waves, it has instead managed to sweep the problem under the rug [2]. It is here in the plumes that microbes have become key players in the questions surrounding the oil spill. Various members of Teske’s lab have gone on five research cruises, which have been part of a joint effort involving several universities. The earliest of these cruises left on May 5, 2010, almost immediately after the spill began, and graduate student Luke McKay was one of those on board. He helped to gather as much data as possible and collected samples with whatever was available. Buckets were thrown overboard to gather oil from the surface and plastic bottles were used as containers. The most recent cruise returned in December of 2010, and, unlike the first cruise, had access to state-of-theart equipment, including a submersible capable of diving to extreme depths, Alvin. Throughout these cruises, hundreds of samples were taken from all three levels of the ocean—the surface, the middle,

Photo courtesy of Kelly Speare.

Figure 2. A CTD rosette is used to locate plumes and collect water samples.

Carolina Scientific and the sediment on the seafloor. A piece of sophisticated equipment called a CTD-rosette looked for low oxygen levels and the presence of hydrocarbons (which is what oil is largely composed of) to locate a plume. Samples taken from inside a plume, when compared to samples taken at any point outside of a plume, have shown that the oil has caused substan-

over such large area has the potential to drastically change ocean ecology. Microbes form the very base of the oceanic food chain; if the balance of population numbers of different species changes drastically, then the entire ecological structure can be altered adversely. It is unclear yet whether the microbe community changes have affected the upper trophic levels much, but it could be because not enough time has passed for noticeable differences to occur. In fact, it seems very unlikely that the food web will not change; the real questions are how much it will change, and whether or not the changes will be catastrophic [3]. The good news is that, generally, there is more than one “stable state” for an ecosystem, so there is the chance that the system will normalize and remain intact. What this future “normal” might be, though, remains a mystery [2].

Photo courtesy of Kelly Speare.

Figure 3. Undergraduate Kelly Speare filters microbes from a sample of plume water.

tial changes in the microbe community [3]. RNA analyses of the sampled microbes indicated that within the plume, there was a significant decrease in diversity of species. In addition, the microbes that were found in the plume were at a greater density than normal, meaning there were more of them. Over 90% of this enriched population was from a single taxon, Oceanospirialles, a group of organisms which feeds on hydrocarbons [4]. These are naturally occurring microbes, and their response to the oil spill is offering an interesting chance to study hydrocarbon-degrading bacteria. By looking at what processes they use to break down the oil, what chemical products come from these processes, and how quickly theses processes occur, these microbes can provide information as to how they could possibly be used to clean up future oil spills [3]. Despite their capacity to do some good, there is a negative side to this shift in microbial population dynamics. A plume is huge, such as the one studied in September that was 20 nautical miles wide, and such skewed density and diversity

Maggie Hunter is a sophomore Biology and English double major.

References

1. Cleveland, Cutler. Deepwater Horizon oil spill. Encyclopedia of Earth. 2010, <http://www.eoearth.org/article/Deepwater_Horizon_oil_spill?topic=50364>. 2. “Black and Blue: Beneath the Oil Spill Disaster.” Produced by the University of Georgia. <http://www.youtube.com/watch?v=xJA7Ax-aUXY>. 3. Interview with Luke McKay and Tingting Yang, 2/10/11 4. T.C. Hazen, et al. Science Magazine. 2010, 330, 204-208.

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Carolina Scientific

Antibiotics Making a Comeback Nabila Sarki, Staff Writer

magine a world where antibiotics no longer effectively treat infection. Each year in the United States, 90,000 deaths are a result of antibiotic resistance in the body, increasing from 13,000 in 1992 [1]. Dr. Scott Singleton from UNC’s Eshelman School of Pharmacy is working to find a way to halt antibiotic resistance. Inspired by his interest in health care, Dr. Singleton is trying to make drugresistant bacteria incapable of defending themselves against pharmaceuticals that are already on the market [2]. In the past 13 years there have only been 10 antibiotics approved by the Federal Drug Administration (FDA) [1]. The lack of new drugs Dr. Scott Singleton, suggests that a new approach UNC Eshelman School of Pharmacy to attacking these bacteria is needed. When an antibiotic is ingested, the infectious bacteria becomes damaged and stressed. Antibiotics do not immediately kill the targeted bacteria, but instead cause it to go into a state of mutation that may prevent bacteria cell death. DNA alterations can occur, causing a stress-provoked form of DNA repair. The bacteria ultimately become genetically changed, increasing their likelihood to survive and pass the new mutated genes to their daughter cells [2]. As this process continues, the bacterial cells develop genetic changes that could cause a prescribed antibiotic to no longer work, leading to drug resistance. An important factor in the development of drug resistance in bacteria is the enzyme RecombinationA (RecA) (Figure 1). Dr. Singleton described RecA as a “SOS enzyme,” allowing the bacteria to overcome the killing properties of the antibiotic [2]. This enzyme activates the stress response of the bacterial cell, and repairs the stressed cell through adaptive evolution.

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Without RecA, cells are no longer able to mutate. If bacteria were to lose its ability to mutate, it would become impossible for them to fight the damaging effects of antibiotics. Dr. Singleton’s research strategy is to stop RecA from allowing bacteria to alter DNA. RecA is inhibited by adenosine diphosphate (ADP) and other related molecules [2], which was used to test resistance of RecA to Escherichia coli (E. coli) (Figure 2). In order to better understand RecA, Dr. Singleton first built a small molecule to interact with the enzyme. The molecule N6-(1-naphthyl)-ADP was

By Emw2012 (PDB structure 3cmt, generated in PyMol) [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0), via Wikimedia Commons

Figure 1. A crystal structure of the protein RecA in complex with DNA.

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Credit: Photo by Eric Erbe, digital colorization by Christopher Pooley, both of USDA, ARS, EMU.

Figure 2. A cluster of E.coli growing together.

utilized as a competitive inhibitor of RecA. In this experiment, the lab used the principles of negative design to stop RecA from producing non-productive DNA strands when it came in contact with non-targeted enzymes. They found that N6-(1-naphthyl)ADP has the ability to stop RecA from binding to DNA and making certain filaments. These filaments are active in altering the cell’s DNA [3] and could potentially cause the bacterial cell to become resistant to an antibiotic. Dr. Singleton’s research could prevent bacteria from becoming resistant. Ideally, traditional antibiotics in conjunction with new treatments could eliminate resistance before it becomes a problem. Ultimately, researchers hope to stop antibiotics from becoming part of the past. In the future further steps will be taken in order to fully prevent bacterial resistance.

Nabila Sarki is a freshman Biology major.

References

1. Wigle, T. et al. The RecA Protein: An Antimicrobial Target for the Suppression of Growth and Drug Resistance. Poster. 2. Interview with Scott F. Singleton, Ph.D. 2/10/11. 3. Lee, A. et al. Journal of Medicinal Chemistry, 2005, 48, 5408–5411.

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Carolina Scientific

Thinking Positively About Restoration and Conservation in Aquatic Communities Patrick Fox, Staff Writer

n order to protect any ecosystem, it is necessary to understand how its organisms interact with their own kind as well as other species. A frequent problem with examining such relationships is that researchers have simply focused on negative examples (where certain species hinder the prevalence of others) such as predation, competition, and parasitism. A project carried out by five researchers, including UNC Biology professor John Bruno, suggests that positive interactions such as mutualism, commensalism, and cascade effects should be considered in the preservation and restoration of aquatic communities. The facilitation of positive interactions is not new to restoration and conservation efforts, as the propagation of nurse plants and foundation species has been utilized in the past. For example, culms of grass

were planted in clusters in marshes to promote shading and aeration of the oxygen-deficient soil [1]. Still, these were minor factors of larger projects, and positive interactions remain underestimated and greatly unexamined by todayâ&#x20AC;&#x2122;s coastal, marine, and aquatic biologists. Different types of positive interactions need to be considered and examined in order to be successfully applied to aquatic ecosystems. The presence of one species can greatly influence the entire ecosystem and allow many other species to inhabit it. For instance, herbivorous animals such as Diadema urchins (Figure 1) and scarid fishes, which graze on invasive algae, allow coral reefs to exist by keeping algae populations small in order to preserve oxygen for other organisms [2]. Cascading effects are also instrumental to the well-being of a community. In coastal New England environments, cordgrass (Figure 2) stabilizes substrates to allow ribbed mussels to inhabit the ecosystem, which in turn provide a solid substrate for the attachment of barnacles, periwinkle snails, and other invertabrates [3]. Positive interactions such as the aforementioned are vital to the livelihood of any ecosystem, but ecologists need to keep the larger picture in Source: http://www.marine.usf.edu/reefslab/images/reefcake_presentation/diadema.jpg sight. Migrations Figure 1. Diadema urchins, shown here, limit algae growth, preserving the available oxygen and the transportafor other organisms.

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Source:http://www.nwcb.wa.gov/weed_info/Images/weedphotos/Cordgrass-Smooth---Infest-03-07.jpg

Source: http://www.nps.gov/olym/naturescience/pink-salmon.htm

Figure 2. Cordgrass, common in New England, is essential for the survival of many invertebrates.

Figure 3. Pink salmon create positive interactions as both predators and prey.

tion of resources cross the boundaries of many ecosystems and inevitably link ones that are thousands of miles apart. Salmon may spend most of their lives in the ocean, but they play a major part in the river ecosystems where they are born, mate, and die. As predators, pink salmon (Figure 3) are needed in the North Pacific to control plankton populations and biomass [4]. At the same time, the salmon also carry essential nutrients from the ocean to the freshwater and forest ecosystems of the Pacific Northwest, where they themselves provide a key source of protein as prey for bears, eagles, otters, and other animals [5]. It must be noted that distinguishing “positive” and “negative” interactions can be difficult because they all have an effect on one another, and a method employed by ecologists today could very well lead to negative consequences in the near future. Furthermore, what works well for the conservation of one ecosystem may not do so for another. Therefore, it is important for scientists to experiment their approaches before actually applying them to the field. Positive interactions need to be more thoroughly examined by ecologists. All organism interactions with one other have an effect on the state of their habitat. By focusing solely on the negative interactions, scientists are discarding about half of the relationships that take place in nature. We have

a significantly better chance of rescuing our coastal and aquatic environments if we investigate and understand every aspect of their existence.

Patrick Fox is a senior History major. References

1. B.S. Halpern, et al. Front Econ. Environ. 2007, 5, 153-160. 2. P.J. Edmunds, et al. Proc. Nat. Acad. Sci. 2001, 98, 506771. 3. A.H. Altieri, et al. Am. Nat. 2007, 169, 195-206. 4. A. Shiomoto, et al. Mar. Ecol. Progr. 1997, 150, 75-85. 5. National Park Service. Anadromous Fish. 2009, <http://www.nps.gov/olym/naturescience/anadromous-fish. htm>.

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Cutting Carbs Just Won’t Cut it: Investigating the influence of genetics on metabolic function Kristine Chambers, Staff Writer

ave you ever wondered why some people can eat anything and never gain weight while others have to struggle with intense diets to achieve the same results? The answer is rooted in variation: differences in genetics and how certain types of food affect the body greatly contribute to this disparity in results. These deviations may explain why diet and exercise, the two most common interventions for obesity, fail so often. Dr. Martin Kohlmeier, a UNC professor, is interested in applying this knowledge on a practical level: incorporating a person’s genetic information into diet recommendations to create meal plans that account for the uniqueness of the individual. This research, while in its early stages, can prove to be incredibly influential, not just in preventative care but for helping ‘at risk’ populations better manage their health. The main limitation of the traditional diet and exercise model is the assumption that everybody in the same age and gender group has the same needs. People are typically told that eating the recommend-

Figure 1. An artist’s rendition of the ApoA2 protein.

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ed amounts of fats, proteins, carbohydrates and essential nutrients, along with physical exercise, will lead to weight loss or weight maintenance. However, the type of food a person consumes is just as important as the amount. A study done to test the effect different types of dietary proteins have on calDr. Martin Kohlmeier, cium metabolism found UNC Gillings School of that vegetable proteins Public Health. were better absorbed by the body than animal proteins [3]. Such information matters because it shows that different foods, even in the same category, can vary in effectiveness and should be selected accordingly. Dr. Kohlmeier’s research focuses on understanding the difference genetics makes in maintaining a balanced diet. By determining a person’s genetic fingerprint, easily done by taking a blood sample, and using bioinformatics, he has devised a meal plan system that works best for the individual. His program, meant for the general consumer audience, uses thousands of customizable meals that are rated from poor to excellent. It is comparable to a website like MyPlate with an important difference: it accounts for your genetic identity and bring intakes of all major nutrients in lines with the user’s personal needs. In a way, Dr. Kohlmeier is bridging the gap between the individual and community; making individualized attention possible on a large scale [1]. Dr. Kohlmeier specializes in nutrigenetic research because he believes that genetics play a key role in the effectiveness of a person’s diet. He has compiled genetic studies for his meal plan program with one

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Image Credit: Martin Kohlmeier

Figure 3. A sample meal from Dr. Kohlmeier’s system complete with nutrients and the option to explore other combinations.

of the most prominent discoveries being the effect of ApoA2 -265C on weight gain. ApoA2 -265 is a common variant of an apolipoprotein A-II (Figure 1) that bind with lipids and other proteins to form lipoproteins. Interestingly, individuals who carried this genetic variant and ate a slightly higher saturated fat intake (equivalent to 2 pats of butter) were much more likely to gain weight than people with the same exact diet, but had the most common variant of apolipoprotein A-II [1]. If a participant in Dr. Kohlmeier’s study has the ApoA2 -265 variant, however, they would never be able to find out, because this information remains masked. In other words, “all you ever see is a meal plan” and consumers will be free to get their nutrition in balance without worrying about the stigma of being genetically abnormal [1]. Making nutritionally sound choices requires much more than just eating your fruits and veggies. Sixty percent of a person’s health can be attributed to genetics or lifestyle patterns, yet there is a short-

age in studies that link the two. Dr. Kohlmeier is a pioneer in his field, and his developing research can contribute greatly in bridging the gap between genetics and nutrition.

Kristine Chambers is a freshman Nutrition major.

References

1. Interview with Martin Kohlmeier 2/11/2010 2. R, Mackintosh et al. Obesity: A research journal. 2001, 9, 462-469. 3. Breslau, N et al. Journal of Clinical Endocrinology and Metabolism. 2011, 66, 140-146. 4. Poort, SR et al. Journal of the American Society of Hematology. 1996, 88, 3698-3703.

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The Secret to Skunking Connie Wang, Staff Writer

fter enjoying a beer on a hot summer afternoon, even some of the more intoxicated students have probably noticed that not long after being out in the sun, their beer has developed an absolutely foul odor. This phenomenon is often referred to as ‘skunking’ and was noted by researchers as far back as 1875. It was UNC’s own chemistry professor, Dr. Malcolm Forbes, who elucidated the chemical mechanisms by which beer skunking occurs. One of the major components of beer, as well as a key player in its skunking process, is a herbaceous plant called hops (Figure 4). Hops are used in the brewing process and contribute to the distinct beer flavor; beers that are stronger in hops content usually have a stronger aroma. The organic compounds derived from hops, isohumulones, are what give beer its bitter taste. Isohumulones are, however, incredibly susceptible to photodegredation. When ultraviolet or visible light strikes isohumulones,

it facilitates a reaction catalyzed by another compound found in beer, called riboflavin. The free radical intermediate produced by the light induced reaction is then converted to 3-methylbut-2-ene1-thiol (Figure 2), causing the foul, skunky odor [1]. Dr. Malcolm Forbes, Surprisingly, this ‘skunky Chemistry professor at thiol’ is not what is found UNC. in skunk secretions but is actually identical to that which is found in feline urine. Forbes was able to elucidate the mechanism of this reaction using time-resolved electron paramagnetic resonance (TREPR) spectroscopy, a powerful technique used to study and identify transient free radical complexes. A strong magnetic field is ap-

Figure 3. (Right) Corona encourages its consumers to drink its product with a lime, which reduces the intensity of the odor caused by skunking by masking it with the flavor of the lime. Figure 1. (Left) Brown and green bottles shield the passages of photons and slw down the skunking process.

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Carolina Scientific plied, followed by an analysis of signals resulting from magnetic moments of electrons [1]. It is because of ‘skunking’ that most beer is sold in tinted brown or green bottles that shield the passage of photons and slow down the skunking process. A variety of newer methods have been developed to combat the problem of skunking. Corona, for example, uses a marketing strategy in which it encourages its consumers to drink its product with a lime (Figure 3). The lime reduces the intensity of the odor by masking it with the flavor of the lime. Chemically modified hops prodFigure 4. (Left) Humulus lupulus, a common species of hops. ucts have also been synthesized. These hops extracts are still susceptible to photodegradation, but do not undergo the same reaction to produce the skunky thiol, and thus fail to develop the odor when exposed to light. Of course, all of these alternatives come at the cost of the beer’s flavor. Forbes’ research has been key to the beer industry, fueling the search for a way to prevent this skunking phenomenon while retaining the original hops flavor. So next time you pick up a beer, be sure to remember the carefully calculated conditions, down to the color of the bottle, that were made to keep your beer from smelling like cat urine.

Connie Wang is a junior Biology major.

Figure 2. (Below) Reaction of isohumulones catalyzed by riboflavin to produce 3-methylbut-2-ene-1-thiol.

References

1. M.D. Forbes. Chemistry. 2001, 21, 4553-61.

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Carolina Scientific

The Greater Meaning of Global Warming Kati Moore, Staff Writer

major issue often brought up in science classrooms, political debates, and environmental news reports is global warming and the resultant environmental changes. But what effect do these environmental changes have on organisms around the globe? Many scientists are still trying to answer this question. Biologist Dr. Lauren Buckley wants to take this question a step further. She explores not only how climate changes, but also how an organism’s own biology affects its population distribution. Buckley seeks to answer the more complicated question, “How does biology (morphology, physiology, and life history) determine an organism’s response to environmental change? [1]” Temperature is an important factor for an organism’s survival in a particular area. This is especially true for ectotherms, whose activity levels depend directly on temperature. Butterflies, for instance, bask in the sun in order to warm up enough to fly. All of the butterfly’s Dr. Lauren Buckley, Assistant Professor at UNC, activities are constrained by flying—finding food, is currently studying the biogeography of climate finding mates, and laychange. ing eggs [2]. The amount of time they can fly is directly related to the number of eggs they can lay. Because of this, knowing the heat tolerances of butterflies can predict their population dynamics. As the average temperature in a butterfly’s habitat increases, the butterfly population may or may not be able to adapt to stay in that location, depending on its thermal tolerances and ability to shift those thermal tolerances.

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Figure 2. The top topographical map of Colorado shows the current distribution of C. meadii butterflies. The middle and bottom maps show the distribution after a 3-degree Celsius increase in temperature, with and without adaptation, respectively, as predicted by Buckley’s mechanistic model.

The Arctic and Antarctic are often cited as being strongly affected by climate change because they are experiencing a greater temperature increase than other areas of the world. But the animals in the tropics may be in more danger, says Buckley. This is because creatures at the poles are already adapted to deal with large seasonal temperature fluctuations, unlike creatures near the equator, where temperatures are fairly constant year-round. As a result, organisms at the poles have larger thermal tolerances than those in the tropics. This means they can survive in a greater range of temperatures, and will be less affected by a greater temperature increase. A common method of predicting where organisms can live is the use of correlative models, which combine location data for different species with environmental variables for those locations. Using these models, scientists can determine the outer limits of environmental conditions that a species could inhabit. These outer limits are referred to as a “climate envelope.” When accounting for climate change, the correlative model assumes that the species will follow the climate envelope as it moves geographically [2].

Carolina Scientific A major problem with the correlative model, says Buckley, is that it does not take into account many biological factors, such as thermal tolerances, and whether these thermal tolerances will evolve with climate change. To take these factors into account, Buckley uses what are called “mechanistic” or “process-based” models, which describe biological constraints on whether an organism can live in a given area. These models give researchers a better overall picture of a species’ population distribution and allow them to more accurately predict how climate change will affect organisms. An example of this Figure 3. Fieldwork includes capturing butterflies and observing them in can be seen with the population other habitats. distribution predicted by Buckley’s which to build models. These can then, hopefully, mechanistic model for C. meadii be translated to the bigger picture of how climate butterflies in Colorado (Figure 2). Though mechanistic models give a better change will affect organisms across the world. This prediction for species distribution with respect to kind of data would be useful for policy makers who climate change, they must be tested against as much have to decide where to place the cap, if possible, on data as possible. Buckley and her coworkers, in their temperature increase. work with butterflies, for example, gather data from For students interested in how climate change fieldwork (see Figure 3) and from museums that hold affects population distribution of different species, information about butterfly traits and how these traits the undergraduate concentration in Global have changed over time. It is important to gather Environmental Change may be a promising option, such data because traits such as wing coloring can says Buckley. affect the body temperatures of an organism – the more black markings on butterfly wings, the higher the rate of heat absorption, which then translates to shorter basking time and the ability to fly sooner. The Kati Moore need for this type of data is a main reason Buckley is a freshman studies the butterflies in Colorado – that is where the Biology major. most information has been recorded over time about the butterfly populations. One challenge to predicting how climate change will affect different species is that each species will respond to temperature changes differently. The question, Buckley says, is how to come up with models for predicting population change that References can represent enough species and still be accurate. 1. Buckley, Lauren. 2011. Buckley Lab – Biogeography of Researchers have to rely principally on case studies Climate Change. <http:// http://www.unc.edu/~lbuckley/lab/ – in-depth studies of just a few organisms – from pmwiki.php>. 2. Interview with Lauren Buckley. 2/11/11.

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Mind-Body Interdependencies “Positively” Influence Well-Being Jana Lembke, Staff Writer

f you’ve ever tried to hide a strong emotion, such as anger or euphoria, you’ve probably noticed that unconscious and unavoidable physical reactions inevitably reveal your true feelings to others. These types of bodily responses to different emotional states are exactly what interest Dr. Barbara Fredrickson, Bethany Kok, and other researchers at UNC Psychology’s Positive Emotion and Psychophysiology Lab (PEPLab). As the name suggests, part of what the lab studies is how positive emotions influence people’s physiology. Likewise, the team examines how initial physiological factors might affect how, or if, people will experience a certain emotion in response to different situations [1]. “From both of these perspectives, we’re bridging the artificial mind-body division,” Kok explains. “As this research proceeds, we’re seeing more and more

Figure 1. Upward trend of vagal tone and social connectedness

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Figure 2. Positive feedback of vagal tone and psychosocial well-being

that psychological and physiological processes aren’t separate, but part of the same system [1].” The interconnected and reciprocal nature of physical and psychological processes served as the basis for Kok and Fredrickson’s latest empirical study, which focuses on vagal tone as a product and predictor of positive emotions and social connectedness. The vagus nerve, or cranial nerve X, extends from the medulla, down the neck, and into the abdomen, where it innervates the internal organs and sends sensory information back to the brain. Because activation of the vagus typically leads to a reduction in heart rate and blood pressure, it is often used as an index of parasympathetic nervous system activity, or the body’s functioning during a state of rest [1]. Vagal tone (VT) refers to this activity and is calculated by analyzing heart rate variability, or how in sync the heart and respiration are. Most importantly, VT serves as a physiological marker of autonomic flexibility and adaptability; that is, the capacity of the parasympathetic nervous system to adapt to changes in circumstance by modifying emotional arousal, respiration, heart rate, and attention [2,3]. Assuming that the enhanced self-regulation associated with high VT will help people capitalize on socioemotional opportunities as they arise, Kok and Fredrickson hypothesized that the autonomic flexibility indexed by VT would lead to increased social connectedness and positive emotions over time [2].

Carolina Scientific can result in a positive change in vagal tone. This is notable because, until recently, the vast majority of psychophysiological research focused on stress and negative outcomes of psychological stress [1].” The results of Kok and Fredrickson’s study pave the way for more discoveries to be made about the mechanisms governing the VT-emotion relationship. “The vagus is just a cranial nerve, albeit a very influential one, but how do you get from the activity of a nerve to having deeper friendships?” Kok asks. “How do you go from ‘I feel socially connected,’ to ‘my vagal tone is higher’? That’s fascinating to me [1].” In her continued research, Kok is going beyond self-reports to investigate how individuals with high vagal tone act in social situations. Identifying behaviors or skills characteristic of people high in VT might help us understand how social connections are created, and has applications from autism therapies to interventions aimed at decreasing loneliness and Figure 3. Anatomical location of the vagus social isolation [1]. The demonstrated links between nerve, in yellow human thriving and VT illustrate the potential for These resulting opportunistic gains, in turn, were positive social and emotional experiences to have expected to lead to elevated VT. Because high VT physiological impacts that foster an upward spiral of is associated with greater self-control and emotion personal well-being. regulation, closer friendships, superior cognitive flexibility, and feeling more secure in one’s relationships, the expected results lay the groundwork for a positive feedback cycle toward greater autonomic flexibility and psychosocial well-being. To test their hypothesis, the researchers measured the VTs of 73 community-dwelling adults at the beginning and end of a 9-week period during which the participants monitored and reported their positive emotions, and the degree to which they felt socially connected each day. As expected, VT and wellbeing reciprocally predicted one another [2]. Adults who possessed higher initial levels of VT increased in social connectedness and positive emotions more Jana Lembke is a rapidly than others. Additionally, participants who junior Psychology reported increased connectedness and positive emomajor. tions showed increased VT, independent of their initial levels. “We’ve shown that a physiological variable, vagal tone, can influence the effectiveness of a psychologi- References cal intervention—a body-mind link,” says Kok. “In 1. Email with Bethany Kok. 2/5/10 2. Kok, B. E., and Fredrickson, B. L. (2010). Biological Psyaddition, our work is one of the first studies to show chology. 85, 432-436. 2010. that psychological change, increasing well-being, 3. Powerpoint Presentation by Bethany Kok, 2/5/10.

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The Physicist’s Playground Matt Dutra, Staff Writer

he future of nanotechnology may lie no physicists alike, including UNC’s own Dr. Dmitri farther away than your desk drawer. Most Khveshchenko. While many scientists are racing current technology is silicon-based – to their labs to fold and unfold layers and layers of computer chips, motherboard circuitry, you name Scotch Tape in the hopes of finding graphene, Dr. it – it probably relies on silicon. While this hasn’t Khveshchenko instead prefers to take a more mathbeen a problem thus far, silicon-based technology ematical approach to describing what makes this will reach its highest potential within around 10 carbon lattice so interesting. years, maybe as soon as 2015[1], due to its limits on Physically speaking, graphene has incredible heat dissipation – a problem central in developing potential as a semi-conductor. In any semi-conducbetter and better nanotechnologies. With these dates tive material, there exist two energy bands of interlooming ever nearer, est – a lower energy materials scientists valence band, in which have been searching for ground state valence plausible alternatives electrons lie, and a to silicon. Now, back higher energy conducto your desk drawer. tion band, in which Hopefully, if you open there are no ground it, you’ll find a pencil state electrons. Sepaor two. rating the two bands As all good colis a band gap, a sort of lege students know, void where electrons pencil lead isn’t actucan never reside. When ally lead at all – it’s electrons in the valence graphite. If you were band absorb energy, to apply a layer of they can be excited into Scotch Tape to a piece the conduction band, of graphite and fold which allows them and unfold the sticky more freedom to move sides, you would find about. It is this capabilthat graphite is comity of charged particles posed of layers. Each to move within the conindividual monolayer duction band, known as – a hexagonal network charge-carrier mobility of carbon atoms (Fig(or more simply, carure 2) – is known by rier mobility) that disthe name of graphene, tinguishes good semiand it is this compound conductive materials that’s caught the at- Figure 1. The Dirac points in graphene are points at which from bad ones tention of many ma- the otherwise separated valence band (green-yellow) and Graphene, surprisingterials scientists and conduction band (red-blue) touch. ly enough, has extraor-

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Figure 2. The molecular structure of graphene is a single layer of a hexagonal carbon lattice.

dinary carrier mobility. According to Dr. Khveshchenko, this is because the valence and conduction bands in graphene actually touch in six points, known as Dirac points (Figure 1)[1]. Furthermore, gaps can be induced in these points [2] through the application of an external magnetic field, which, if controlled, would allow graphene to function in conventional transistors – central parts of things such as computers, radios, electric parts of automobiles, etc. However, the Dirac points in graphene are of interest to Dr. Khveshchenko for a second reason – the movement of electrons near them can be described mathematically by the relativistic Dirac equation. While this may seem underwhelming to those of us who aren’t theoretical physicists, Dr. Khveshchenko describes the phenomenon as a “physicist’s playground”, capable of “demonstrating phenomena…..such as Klein’s Paradox (reflectionless tunneling through potential barriers), atomic collapse (unstable electronic Dr. Dmitri Khveshchenko, orbits in the presence physics professor at UNC. of charged impuri-

ties), Zitterbewegung (oscillations of the center of a propagating electronic wave packet), and Schwinger’s particle-antiparticle pair creation in an electric field” [3]. Graphene has great potential as a semi-conductor due to its charge-carrier mobility and ability to better dissipate heat, can be used to study atomic phenomena in quantum physics, and can be found in objects as commonplace as your pencils. It also has been considered as a replacement for silicon in many microtechnologies, including central components such as transistors – electronic devices present in things such as computers, cell phones, and radios, to name a few. Not bad for a substance that can be isolated with nothing more than determination and a roll of Scotch Tape.

Matt Dutra is a junior Chemistry major.

References

1. Interview with Dr. Dmitri Khveshchenko, 2/7/11 2. Khveshchenko, D.V., Coulomb-interacting Dirac fermions in disordered graphene. Physical Review B, 2006. 3. Emails with Dr. Dmitri Khveshchenko, 2/16/11

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The Game of Telephone and an Analysis of Signal Detection in Animals Madison Roche, Staff Writer

hen playing telephone with your friends, it’s obvious that all it takes is a little misunderstanding to miss the whole point of the beginning sentence. A similar phenomenon occurs when animals try to signal different messages to their friends. Professor Haven Wiley is currently studying signal detection theory, which is leading to some strong predictions about the evolution of signals and responses in animals. For further explanation, think about the analogy of the game of telephone. Just like in the game of telephone, often times there are background noises and distractions which cause weak communication. Most importantly, however, the game involves being

able to detect the words that are being said and the ability to retain and relay this information to the next player. Therefore, there are two main components to both the game of telephone and animal communication; detectability and the receiver’s responsiveness. A lot of things get lost in the shuffle during communication, whether it is the sound being drowned out or the receiver not responding. Studies of animal communication have found that whenever there is a change in the probability of detecting the background stimulation, there is a corresponding change in the probability of a correct detection (Figure 1). This has proved to be a fundamental implication for the evolution of communication and is where the

Graphic Credit: Dr. Haven Wiley

Figure 1. In the presence of noise, receiver’s receptors do not completely separate noise and nignal from noise alone. The receiver’s threshold sets the probabilities s of the four possible outcomes; (1) CD- Correct detection (signal, response), (2) MD- missed detection, (3) FA- false alarm (response but no signal), (4) CR- correct rejection (no signal, no response). This graph displays that the two kinds of errors are not independent and receivers cannot simultaneously minimize MD and FA.

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Carolina Scientific search theory provides great promise for the future studies of the evolution of animal communication. The theory suggests new ways to design experiments in order to include all of the restrictions put on a good communication line. He claims that with this approach, we can learn more about an animal’s adaptations for situations with a lot of background noise, the ability to detect and discriminate signals, and the evolution of increased detection and receiving abilities [1]. In other words, how to create a flawless game of telephone.

Image Credit: http://www.cee.unc.edu/faculty.cfm.

Figure 2. Professor Richard Haven Wiley.

signal detection theory comes in. According to Professor Wiley, the signal detection theory provides a solution to this problem and other weaknesses of weak communication. After extensive research, experiments, and calculations Professor Wiley has formed a complex conclusion. First of all, the signal detection theory leads to a prediction that receivers evolve to optimize the net utility of their responses. Based on the theory of natural selection, the fit animal can survive and reproduce to make the optimum offspring. Receivers that can adapt and evolve to optimize their receiving against Madison Roche is a the distractions will have the optimum receiving sophomore Biology masignals, increasing their fitness. jor with a Chemistry and In turn, signalers should then evolve with a balSpanish double minor. ance between increased detectability of signals, increased complexity of encoding and restriction of signals to intended receivers. This means that signaler’s predators are likely to increase their ability to intercept messages not intended for them. This is similar to when a group of gossip-hungry girls eavesdrop to hear other people’s secrets. The group of girls developed an increased sense of hearing, so if others do not want the gossip girls to hear them, there is a need to further code their conversation References with their friends to avoid interception. 1. R. H. Wiley. Advances in the Study of Behavior. 2006, 36, Professor Wiley has broken down why signal re- 1-31.

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Astronomical Kingdom Apurva Oza, Staff Writer

ince the days of Stonehenge, astronomy has evolved from observing solstices and alignments to capturing star explosions in the distant universe; from stones and pyramids on the ground to robotic telescopes on the highest mountain tops of the world. In the age of modern astronomy, you don’t need to physically journey to distant mountain tops. With an iPhone or a Blackberry you can, with a click of a button, submit an observation to a galaxy far, far away from virtually anywhere via the Internet. This is exactly the kind of thing UNC Professor Dan Reichart and his research team have been creating and perfecting—the Skynet Robotic Telescope Network. Using Skynet, a tap of the keyboard can open a clam shell telescope dome 7400 km away— and yes, it is named after the artificial intelligence system that controlled robots in The Terminator.

The web interface started in 2005, governing the six primary PROMPT telescopes that were built to rapidly capture the afterglows of gamma-ray bursts, or GRBs—highly energetic explosions of stars occurring billions of light years away. Since then, Skynet has expanded its reign of robotic telescopes worldwide, and has made astronomy more practical and feasible. The numbers aren’t bad: 30,000 North Carolina grade school students, 12 undergrad institutions, and 20,000 members of the general public using the system for their own astronomy projects, cutting-edge research published in more than a dozen journals, and a whopping total of 3.2 million images taken so far [1]. Scientists use the ’scopes for a variety of astrophysical research, from chasing asteroids to taking pretty pictures for NASA’s Astronomy Picture of the Day. The UNC team mostly focuses on cosmol-

Figure 1. The six PROMPT robotic telescopes in Cerro Tololo, Chile.

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Figure 2. One of the PROMPT telescopes shown in an open dome.

ogy—the study of the universe’s beginning and how it evolves. During a gamma-ray burst, two jets of radiation and energy are released. If we are lucky the axis of the jet aligns with Earth and we are hit with a measurable but not dangerous surge of gamma rays. The distant blasts of gamma rays are detected by a satellite called SWIFT orbiting the Earth. The message is then relayed to robotic telescopes like PROMPT, and the race begins. The scopes must immediately slew (astronomy jargon for rotating a telescope) and start exposing or else the vital data will be gone forever. One can imagine doing this science a few decades ago, before Skynet: stumbling out of bed into the observatory (granted you live there), messing with the controls in your sleep, only to find out that you missed it—you were too late. Once the team gets good data, they quickly perform photometry on the burst—measuring its brightness over time—and get their results out to the GRB community via “GRBlog,” where GRB scientists report their preliminary findings. “Waiting for the world to turn around can be a real nuisance when catching GRBs,” says Dr. Reichart. So in addition to the 13 telescopes scattered around the globe in North Carolina, Virginia, Colorado, Thailand, and Italy, the research team has received a grant to build 4 more PROMPT telescopes at Siding Springs Observatory, Australia. “…the sun will never rise,” jokes graduate student Justin Moore, pointing out the fact that due to the longitude of Australia in relation to Chile, astronomers won’t lose time waiting for the Earth to turn around when a GRB goes off—there will always be a ’scope handy.

Soon the network will also be observing the universe at radio wavelengths, capturing phenomena we can’t normally detect in visible light. A 20-meter radio telescope in Green Bank, West Virginia, is also an addition to Skynet. The team often goes on expeditions to new observing sites. If a university has an old telescope sitting around that isn’t used much, it can be automated, remotely-controlled and used nightly by anyone. Take the 24-inch telescope in the dome at the Morehead Planetarium, for example. Historic and monumental as it may be, it spent most of its time sleeping under the Carolina Blue sky. “I’m going to put this old guy to use,” says Josh Haislip as he finishes the final touches on installing conductor rails on the dome with Justin Moore. “Soon Morehead guest night could be every night from a laptop.” Another goal the UNC team has is to transform the Skynet interface so that is more user-friendly. They envision a place where people can exchange ideas, data, images, and interact—a kind of networking site for researchers. Despite the convenience and accessibility of remote observing, many people would still prefer to do astronomy at the observation site itself, and feel that thrill. I think every astronomer should make the journey to an observatory at least once to see where the images are coming from. My first journey was at the Pic du Midi Observatory, lodged at 2877 m on top of the Pyrenees mountains. Looking out across the snow-glazed mountains, I felt like I was looking across the pride lands in the movie The Lion King: “…everything the light touches is our Kingdom.” In our Astronomical Kingdom, it is every photon we collect in the sky that is ours. When we can govern the sky with an army of robotic telescopes equipped and ready to fire at our command, cosmic events will have a tougher time disappearing before we can catch them. And it is only once we catch them that the universe’s most puzzling questions will be answered.

Apurva Oza is a junior Physics major. References

1. Interview with Dr. Daniel E. Reichart. 2/10/2011. 2. Thorsett, S.E. Astrophysical Journal Letters 1995, 444, L53 3. Melott, A.L. et al. . International Journal of Astrobiology 2004, 3, 55–61. 4. Petit. P et al. Astronomy and Astrophysics, 2010, 523.

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“Satisfaction of one’s curiosity is one of the greatest sources of happiness in life.” - Linus Pauling

Carolina Scientific Spring 2011 Thanks to Stephen Farmer and Donald Hornstein for funding and support. Front Cover: Coral Reef, Credit: Richard Ling, www.rling.com Table of Contents: Nanowire Array, Microspace 4, Credits: Z.L. Wang, Georgia Tech and Dr. Zhengwei Pan, Dr. Zhanjun Gu, and Dr. Feng Liu, University of Georgia This publication was funded at least in part by Student Fees which were

40 Government at UNC-Chapel Hill. Spring 2011, Volume appropriated III Issue IIand dispersed by the Student