Our students are strongly encouraged to collaborate with faculty to do research.  Both on-campus and off-campus opportunities are available for students who wish to enrich their undergraduate experiences by doing research and by presenting their work at national and regional conferences.  Some recent accomplishments of our students are highlighted here.

 

-- At the Regional meeting of Tri-Beta (the Biology Honor Society) in Birmingham, AL, April 3-5, 2009:

    Six students presented posters or talks.

    Chivonne Thayer won regional third place for best talk on her work "The Effects of Light Intensity on the Grouping Behavior of Aedes albopictis (Asian Tiger Mosquito) Larvae".

    Sara Roberson won regional second place for best poster on her work " The Effects of Forest Fragmentation on     Ectoparasite Loads of Small Mammals on Meredith College Campus".

    Sara Roberson was elected to serve as the regional Tri-Beta vice-president for the coming year.   

-- At the North Carolina Academy of Science meeting at Warren Wilson College in Asheville, NC, April 3-5, 2009:

   

     Four students presented posters or talks.

 

     Krishna Chagarlamudi’s presentation, “Quantification of Pharmaceutical Uptake by Corbicula fluminea”, earned second place in the Derieux Award for undergraduate research in her section: Ecology, Environmental Science, and Conservation Biology.  The Derieux Award for Excellence in Undergraduate Research is presented for presentations at the NCAS annual meeting.  Presentations are judged on scientific merit and presentation.

     Terri Richards was elected Historian for CANCAS for the coming year.

 

 

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Student Research Spring 2009

Potential Genetic Similarities in Neurologic Disorders Treated by Metal Chelation Therapy

Neurologic disorders are on the rise in the United States due to the increased demand individuals now subject their body’s to.  The purpose of this project is to determine if there are any genetic correlations within a certain group of neurologic disorders, including Alzheimer’s Disease, Parkinson’s Disease, etc.  Disorders such as these are now being targeted as a large market for pharmaceutical companies.  Chelation treatments which target the removal of various metal ions, have been developed in the last several years.  At this point these treatments are non-disease specific, targeting generalized symptoms. This project will review previously collected data on specific disorders, genetic linkage, and effect of chelation therapy.  The hypothesis is that there is significant genetic correlation within this group.  This would allow for refinement of chelating medications to target specific disorders via the mechanism of action, rather than blanket treatments, which target only general symptoms.  Some correlation has been found in location of disorders in the human genome.  This work is related to an internship with Dr. Diana Greene-Chandos, M.D., Chief of Neurology at Forsyth Medical Center in Winston-Salem over the summer of 2008.

Student:  Cynthia N. Abell

Mentor:  Dr. Francie Cuffney  

 

 

Protection and de-protection of amine terminated self-assembled monolayers on gold:

towards peptide synthesis on pH switching

This project is one of five projects where Meredith students are paired with postdoctoral research associates at Duke University.  This particular project deals with the surface chemistry of Self-Assembled Monolayers (SAMs) on gold, evaporated onto primed glass slides.  SAMs are thin films of organic molecules that spontaneously adsorb onto solid substrates, yielding a well ordered layer with specific terminal functionality.  A model SAM system is alkanethiols on gold.  The purpose of this project is to establish protection and de-protection reaction schemes, using pH as the stimulus to eventually allow for the synthesis of peptides from the SAMs.  The chemistry involved in this project is from the standard organic chemistry toolbox.  Fmoc and tBoc bind to amine groups and can be removed using a base or an acid respectively.  Throughout the course of this study several techniques will be used to confirm the steps of protection/de-protection chemistry including; contact angles, X-Ray Photoelectron Spectroscopy, and fluorescence microscopy.  The goal of this research is to standardize these chemical protocols so that they can be used in conjunction with pH switching surfaces, which in turn will be used to fabricate on-chip peptide synthesis.  This work is funded by Stefan Zauscher and Benjamin Yellen of Duke University.

Student:  Cynthia Abell

Mentor:  Dr. Robert Ducker - Duke University, The Center of Biologically Inspired Materials and Material Systems

 

 

Effects of Ginkgo Biloba and Herbal Weight Loss Supplements on the Asiatic clam Corbicula fluminea

 

In 1999, the U.S. Geological Survey reported detectable amounts of pharmaceuticals in surface waters.  Researchers tested for 95 chemicals in 139 streams across 30 states.  At least 7 contaminants were found in each stream with some having as many as 35 contaminants.  Little is known of the effects of these contaminants on aquatic organisms.  This experiment studies the effects of herbal supplements on aquatic organisms, specifically the Asiatic clam Corbicula fluminea.  Herbal supplements studied were Gingko biloba and an herbal weight loss compound containing EGCG.  The hypothesis is that herbal compounds will have little effects on the clams. The weight loss supplement will have more of an effect due to the fact that it contains caffeine, a substance previously shown to affect clam gill function. Methods include treating clams with dilutions of herbal supplement to find LD50, lethal dose for 50% of exposed population.  Clams are then exposed to sublethal doses and dissected to microscopically examine gills for alteration in structure or function.  LD50 for Gingko biloba was found to be 500 ppm, five times that of caffeine.  LD50 for the herbal supplement was found to be greater than 1000 ppm for the compound.  

Students:  Dara Bifalco and Megan Rice

Mentor:  Dr. Francie Cuffney

 

HIV protease inhibition abilities of Tylosema fassoglensis

AIDS (Acquired Immunodeficiency Syndrome) is caused by the infection of cells by the human immunodeficiency virus (HIV).  AIDS is a growing issue not only in America but all around the world.  The Centers for Disease Control documents more than 980,000 cases in America, 25.8 million cases in Africa and 7.4 million cases in Asia. To reproduce, the virus needs an enzyme called HIV protease, which processes viral proteins into their functional form.  Inhibitors of HIV protease are among the most common anti-HIV drugs in the market.  However, these drugs are extremely expensive, and the HIV virus is becoming resistant to them. Sunguprot is a Kenyan herbal anti-HIV remedy that contains root-extracts of Tylosema fassoglensis as its active.  This plant is rich in inhibitors of the enzyme trypsin (protease).  We reasoned that the anti-HIV activity of this plant is due to the presence of an HIV protease inhibitor.  We tested protein fractions obtained by chromatography for trypsin (protease) inhibition.  Fractions with most trypsin activity will be tested for HIV protease inhibition activity.

Students:  Jessie Breazeale, Aatiqah Khalid, Jill Palchinsky

Mentor:  Dr. Karthik Aghoram

 

Studying Nicotinic Receptor Therapy in the Prevention of Alzheimer’s Disease

 

Alzheimer’s is a neurological disease which strikes millions of elderly individuals every year. The disease is degenerative and ultimately fatal and its exact cause is not yet known. There are numerous potential treatments for preventing Alzheimer’s but my I will be discussing three options, Aricept, Exelon, and nicotine. My research focuses on the aforementioned drugs which target nicotinic receptors and how they may potentially aid in preventing Alzheimer’s.  The ability of these drugs to prevent Alzheimer’s is a highly debated topic in the scientific world and I will be conducting a literary review of primary sources to determine the effectiveness of each treatment.  Each drug acts on nicotinic receptors which are ion channels found on neural receptors.  Nicotinic receptors are bound to by acetylcholine, a chemical messenger that transmits impulses across neurological junctions, as well as nicotine.  Will these drugs really work to prevent Alzheimer’s?

Student:  Mary Megan Brooks

Mentor: Dr. Andrea Marritt

 

Morphology of Corbicula fluminea After Exposure to PPCP’s

Pharmaceuticals and Personal care products (PPCP’s) are pollutants that have not been thoroughly researched or monitored. Although not highly potent in small doses, PPCP’s could cause irreversible effects on aquatic wildlife. One species being affected by PPCP’s is Corbicula fluminea, more commonly known as Asiatic clams. Corbicula fluminea filter water through their gills in order to obtain food and oxygen. Filter feeders seem to be the first and most severely affected aquatic organisms when exposed to PPCP’s. Thus research needs to be done to examine any variation in internal gill morphology or function occurring when certain PPCP’s contaminate the water. Gill tissue was extracted from clams after exposure to various PPCP’s.  Tissue was examined microscopically for evidence of PPCP exposure. Extraction of gill tissue was performed under a dissecting microscope and the tissue was placed on a slide and examined under a compound microscope. Video and still photographic images of the gill and cilia were produced using a digital camera mounted to the microscope. Initial results document crystal accumulation on the gills of clams exposed to acetaminophen and variation in cilia movement when exposed to caffeine.

Student:  Meredith Cowart

Mentor: Dr. Francie Cuffney

 

 

Screening for Wolbachia in Apis mellifera (Western honey bees)
 

Apis melifera, or the western honey bee, is a keystone in American and European agriculture. Recent concerns have developed regarding Colony Collapse Disorder, or CCD, a condition in which the bees apparently abandon the hive.  Although no cause for CCD has been established, it has been suggested that a pathological agent may be involved.  Wolbachia are intracellular bacterial parasites that may play a role in CCD.  Wolbachia creates a mating preference among insects due to problems concerning cytoplasmic incompatibility and parthenogenesis, which can lead to non-viable matings. To determine if Wolbachia are associated with Apis species, bees were dissected to remove abdominal tissue. A modified DNA extraction protocol was developed using the Promega DNA Purification kit to maximally extract DNA from the abdominal tissue.  The DNA extractions were verified via gel electrophoresis. Extracted DNA will be used as template in a Polymerase Chain Reaction (PCR) setup, using Wolbachia specific primers.  If PCR products are generated, it will verify that Apis species are hosts to Wolbachia.

Student:  Krystle Davis

Mentor:  Dr. Jason Andrus

 

 

Comparison of Gastro Intestinal Bacterial Microflora in Apis species

Apis mellifera, or the western honey bee, is a commercially important insect responsible for the pollination of over 100 fruit and vegetable crops in the US, and is responsible for $20 billion in agricultural revenue. Recently, Colony Collapse Disorder, or CCD has caused many to explore solutions to the problem. CCD is a condition where seemingly healthy hives are abandoned, potentially resulting in economic loss and serious ecological implications. This has sparked recent interest in identifying factors involved in CCD, including identifying pathogens. Queen bees engage in polyandry, which produces wide genetic variation within a single hive. Genetic variation via different fathers could mean that gut flora found in workers could vary as well, which in turn may influence disease susceptibility. The purpose of this project is to develop a molecular means to identify bacteria in the gut flora of Apis species.  In order to successfully indentify the bacteria in the gut flora the honey bee we will have to generate a library of plasmids into E. Coli, then will isolate the plasmids from E.Coli in order to perform DNA sequencing. By this process we will hope to correctly identify the different types of mircoflora in the gut flora of Apis species. So far I have ran PCR on several be models using universal primers. As a result I have yet to receive any PCR product and I will have to go back and verify that the DNA that I extracted from the bee G-I tract is still intact.

Student: Morgan Davis and Shaelia Hutchinson

Mentor:  Dr. Jason Andrus

 

Buffy Coat Proliferation in Hematocrits

It has been observed that the white blood cell (WBC) layer or buffy coat in a hematocrit tube stored at room temperature (26 degrees C) increases in size during the time period of 2 to 60 hours after blood is collected. The effects of time and environmental parameters on the size of the white blood cell layers of hematocrits were investigated during this research. After being centrifuged for five minutes, capillary tubes of human blood separate into three layers: red blood cell layer, white blood cell layer, and a plasma layer. Each tube was observed at time 0, 24, 48, 72, and 96 hours, and each layer was measured for change. The environmental parameters that were altered in this research were heparinized and non-heperarinized capillary tubes, temperature, capillary tubes with and without parafilm covers. Heperin had minimal affects on the WBC layer. Increasing the incubation temperature from 26 degrees C to 27 degrees C at which the hematocrits had minimal affects on the WBC layer; whereas tubes incubated at 7 degrees C were observed to have smaller changes in WBC layer size over time. Parafilm covered tubes had less change in the plasma layer than the tubes without paraflim, leading to the hypothesis that the plasma exposed to air were evaporating. Our findings indicate that increased time, decreased temperature, and parafilm covered hematocrit tubes all alter the size of the white blood cell layer. These results lead to the question of why are the white blood cell layers of hematocrits increasing in size.

Student:  Kelsey Graven

Mentor: Dr. John Mecham

 

Studying the Spawning and the Fertility of Betta Plakats

    To study the effect of frequent spawnings on egg production and fertility rates of Siamese Fighting Fish (Betta splendens) variety Plakat (a less inbreed variety), two pairs of Plakats were spawned six times at approximately ten-day intervals.  The number of eggs produced at any one spawning ranged from 190 to 957. The average number of eggs for all spawnings by Pair I was 697.6 and by Pair II was 598.8. The fertilization rate in any one spawning ranged from 0.8% to 94.7%. The average fertilization rate for all spawns for Pair I was 9.0% and for Pair II was 64.3%.  Not all fertilized eggs developed into fully-formed embryos. Partial embryonic development occurred in some spawnings and the frequency of partial embryonic development ranged from 0.0% to 3.2%. Pair I had no partially developed embryos in any spawning while Pair II had an average of partially developed embryos for all spawnings of 1.1%.  The low frequency of fertilization in pair one may be the result of genetic factors. 

Student:  Brittany Lindgren

Mentor:  Dr. Bob Reid

 

Fabrication of a SERS-Active Plasmonic Sensing Platform for

 Biochemical and Biomedical Analysis 

 

 Surface enhanced Raman Spectroscopy (SERS) has enormous potential applications in sensitive, selective analysis for diagnostic purposes. The Vo- Dinh laboratory has a greater project of developing technology that would make the diagnosis for a variety of disease speedy and accurate through spectroscopic analysis of DNA and mRNA. SERS, one such analytical tool most suited for this purpose, can be defined as a Raman spectroscopic technique that provides greatly intensified Raman signal from Raman-active analyte molecule adsorbed on to certain specifically prepared metal surfaces. This project focuses on the fabrication and testing of SERS-active surfaces in the form of silver island films and SERS-active optic fiber arrays. We start with making SERS-active arrays by depositing silver nanoparticles on to different SiO2 substrates such as glass slides and optic fibers. We will then optimize a hyperspectral imaging system for 2- Dimensional imaging of the fabricated SERS-active arrays. Using these SERS-active arrays, the eventual goal of the project is detection of multiple DNA and mRNA sequences indicative of disease.

Student:  Bethlehem Mekonnen

Mentor:  Dr. Jonathan Scaffidi - Duke University, Department of Biomedical Engineering

 

Isolation and Purification of a Potential HIV Protease Inhibitor from Tylosema Fassoglensis

HIV/AIDS is present in every country and is responsible for the death of nearly 3 million people every year. Because it is such a global problem, it has become increasingly more important for new treatments to be created. In Kenya, Sunguprot, an herbal concoction of nutrients and the extract of an African plant called Tylosema fassoglensis, has recently been used to combat HIV and has had positive results treating the symptoms of the virus. It has been hypothesized that the reason HIV patients see a decline in their symptoms is due to a potential protease inhibitor that can be found in Tylosema fassoglensis. Using the protocols for isolating trypsin inhibitors from sweet potatoes developed by Sugiura et al, we applied the same protocols in an attempt to isolate a potential HIV protease inhibitor from Tylosema fassoglensis. Our results have shown that there are some protein amounts present in fractions collected from Tylosema fassoglensis, but we need to do more research to determine if any of these proteins are HIV protease inhibitors. Continued research needs to be done in order to identify and isolate the inhibitors.

Student:  Meredith Moore

Mentor:  Dr. Karthik Aghoram and Dr. John Mecham

 

 

Cardiac Function in Freshwater Snails: Temperature and Embryonic Development

Previous studies of the marine snail Tegula have shown that an increased in water temperatures through the thermal tolerance range will cause the heart rate of the snails to increase. As the upper limits of the thermal tolerance range are reached the heart rate will decrease and eventually stop.  The objective of this study is to determine the effect of temperature, body size and mass on the heart rates of the tropical freshwater snails, Biomphalaria glabrata.  Snails were classified as small (<1.0cm diameter), medium (approximately 1.5cm diameter), and large (approximately 2cm diameter).  The average heart rate was determined for 5 snails of each size at ambient water temperature (20°C) size and at 7°C and 37°C.  The average heart rate for small, medium and large snails was 43.26 beats per minute (bpm), 31.05 bpm and 30.83 bpm respectively.  Embryonic development of the heart in two freshwater snails, B.glabrata and a local species Physa heterostropha has began.  Development time to an observable heart rate is approximately 48 hours in B.glabrata.  Future research will determine the effects of temperature on embryo heart rates. 

Student:  Phuong Nguyen

Mentor: Dr. John Mecham

 

Behavioral Effects of St. John’s Wort on Corbicula fluminea

Pharmaceuticals and Personal Care Products (PPCPs) go into our surface waters, disrupting ecosystems. Filter feeders such as Corbicula fluminea indicate stream health because they concentrate pollutants when feeding. This project investigates the effects of the organic mood elevator St. John’s Wort on C. fluminea. Clams were found to have a very high tolerance for St. John’s Wort with the lethal dose above 900 parts per million. Clams were then exposed to sublethal doses and behavior observed. After four days of exposure, the clams were removed and placed into clean freshwater. Their behavior was observed for recovery speed to normal behavior. Separately, four clams were dosed in a graduated cylinder with a thick layer of beads. The dosed clams were compared to clams in freshwater to determine if the clam dig away from the contaminated water. Neither group dug into the beads, contrary to their observed digging habits in nature. Understanding how organisms react to pollutants such as PPCPs can support efforts to decrease their release into watersheds, whether accidental or purposeful. C. fluminea appear to remain mostly closed while in dosed water, but do not appear to dig away from the contaminant. However, they seem to resume normal behavior rapidly.

Student: Jessica Prescott

Mentor:  Dr. Francie Cuffney

 

A Study Regarding Sickle Cell Disease:  Examining the Correlation Between the Number of Patient Crises and the Development of Limb and Feet Abnormalities             

Sickle cell disease refers to a category of genetic illnesses in which the hemoglobin has an irregular, sickled shape when oxygen saturation is low.  Painful episodes, or “crises,” occur when these sickled red blood cells clump together and interrupt normal blood flow or limit oxygen concentration in affected tissues and organs.  Currently, there is SCD research that aims to better understand the totality ofbiological and psychosocial factors that influence pain and other disease-related outcomes.  However, there is no conclusive research that explores the relationship of psychosocial factors like depression, anxiety, and hostility to painful crises of the upper and lower limbs and feet.  We administered a comprehensive 700 item questionnaire to 156 individuals with SCD seeking care from the Duke Sickle Cell Clinic located in Durham, NC to provide information on mood, the severity and frequency of painful episodes, and information regarding other pre-existing health conditions that affect the lower limbs.  These variables will be analyzed to determine if there are any significant relationships between the pain episodes in the lower limbs and psychosocial factors such as depression, anxiety, and hostility.  Preliminary data indicates a relationship between depression and the average number of pain crises in a month.

Student:  Samantha Price

Mentor: Dr. LeKisha Edwards and Dr. Christopher L. Edwards - Duke University - Clinical Psychology/ Psychoneuroendocrinology    

 

Generating Tamoxifen inducible CreERT2 Constructs

During mouse embryonic development, germ cells form around embryonic day (E) 7.5.  Between E8.5 and E12.5 these early germ cells exhibit limited pluripotency and can be used to generate pluripotent stem cells lines which closely resemble embryonic stem cells (ES cells).  This ability is lost by E13.5, when male and female germ cells differentiate down separate paths.  We want to be able to manipulate gene expression specifically in germ cells during this phase of their development. We will generate constructs containing a Tamoxifen inducible CreERT2, driven by promoters that are active in early germ cells.  By using an inducible Cre we will have greater control over the timing of the deletion of the specified genes because the genes will be active until we inject the mice with Tamoxifen.  This drug will activate Cre to delete our targeted gene.  We will use a modified form of the protocol “BAC Recombineering using the modified DH10B strain SW102 and a galK positive/counter-selection cassette” by Soren Warming, Ph.D.  After the successful creation of the constructs, fertilized eggs will be injected with the plasmids to generate transgenic mice.  These mice will allow us to study genes of interest specifically in the early germline.

Student:  Nicole Pulley

Mentor: Dr. Danielle Maatouk, Duke University, Cell Biology

 

The Effects of Forest Fragmentation on Ectoparasite Loads of Small Mammals on Meredith College Campus

A great problem facing the environment today is deforestation brought on by urbanization.  This forest clearing creates small forest fragments on the edges of urban development.  Forest fragmentation can affect the populations of animals living in the forests.  Meredith College has a 1 hectare forest plot that contains 20 meters of forest edge.  The most prevalent small mammal in the Meredith College forest plot is Peromyscus leucopus, or the White-footed mouse.  Using live trapping, I investigated how forest fragmentation affects loads of ectoparasites on P. leucopus in relation to the edge of the forest.  The project also investigates other factors that could affect parasite load, such as age or sex of the mouse.  Over the course of two months, the parasites found on P. leucopus were recorded and identified.  Initial results suggested that greater parasite loads were found on mice trapped at the edge of the forest plot.  Initial research also suggested that more parasites were found on males than females and more on adult mice than juveniles.  Knowing the effect of fragmentation on parasite loads is valuable not only to the mouse health, but to human health as well.  Many of these parasites feed on humans, and can be vectors of such diseases as Lyme disease and Rocky Mountain Spotted Fever.

Student: Sara Roberson

Mentor:  Dr. Erin Lindquist

 

Cytological staining of Dynabeads and CD4+ Lymphocytes

CD4+ cell counts in humans are an important indicator of the level of HIV infection. Dynabeads® (Invitrogen Corp.), designed to attach to CD4+ cells, are used to identify this particular type of lymphocyte. Preliminary research has shown that CD4+ cell/ Dynabead® interactions may alter the surface of the Dynabeads® as shown by the inability of attached Dynabeads® to absorb stains used in hematology. The purpose of my research is to determine the effect of CD4+ cell/ Dynabead® binding on the ability of the bound unit to absorb various cytological stains. Three staining techniques were used: an eosin based staining procedure, methylene blue, and Nigrosin. If the interaction with the cell to the Dynabeads® does result in differential staining, this would be important information for further investigations on the application of Dynabeads® for the identification of specific cell types. In my research I found that the interaction between CD4+ cells and the Dynabeads® resulted in the CD4+ cells taking up stain and the Dynabeads® not.

Student: Annelise Rogers

Mentor:  Dr. John Mecham

   

The Effect of Insect Herbivory on Liquidambar styraciflua (Sweetgum) and

Acer rubrum (Red maple) in the Meredith College Forest

Insect herbivory can have a negative effect on the survivorship and growth of tree seedlings.  Most of the research conducted on insect herbivory has dealt with tropical tree species.  There has been very little research specifically conducted on Liquidambar styraciflua (Sweetgum) and Acer rubrum (Red maple). I hypothesized that insect herbivory has an impact on seedling growth and survival by removing leaf area, and herbivory will be higher closer to the forest edge. I germinated seeds collected from Liquidambar styraciflua and Acer rubrum trees surrounding the Meredith College forest plot in the greenhouse. To determine the effect of herbivory in the Meredith forest, I plan to transplant the seedlings and surround them with mesh of various thicknesses to allow only herbivores of a particular size to access the seedlings. For the control treatment, another group of seedlings will be planted without the mesh.  I expect that the treatment surrounded with fine mesh will have the greatest amount of seedling survivorship because of minimal leaf area lost.  My project will provide more information about the effect of insect herbivory on seedling establishment in an urban forest environment and could be important in restoration projects where seedlings may be planted into urban sites.

Student:  Jillian Stancil

Mentor:  Dr. Erin Lindquist

 

Nicotinic Receptors Modulate Levodopa Treatment for Parkinson's Disease

Parkinson’s disease is a disorder of the nervous system that is caused by the destruction of brain cells that control muscular movements. This causes a decreased amount of dopamine to be released into the body. Levodopa is a common treatment for Parkinson’s disease because it imitates the effects of dopamine once inside the body. Unfortunately, after long term exposure to levodopa, dyskinesia can occur. Research has shown that nicotine activates the nicotinic acetylcholine receptors and ultimately aids in regulating the release of dopamine into the body. After experimenting with intermittent and constant nicotine treatments, both were found to be effective in reducing the levodopa-induced dyskinesia.

Student:  Lauren Stevens

Mentor:  Dr. Andrea Marritt