Student Research

The PC biology faculty is quick to point out that a good education is not limited to the classroom. There are many research projects available in a broad range of areas under the direction of the faculty in the Biology Department. Some recent research is listed below.

Research Highlight: Meghan Skinner
The Experimental Effects of CO2 Levels on Stomatal Density of Arabidopsis thaliana 

In the majority of plant species, specimens grown in high levels of CO2 have a lower stomatal density compared to those grown in environments of reduced CO2 levels. Developing leaves have even been shown to respond to the atmospheric CO2 levels of their mature levels by developing high or low stomatal density accordingly. Wisconsin Fast Plants of Arabidopsis thaliana, supplied by the Carolina Biological Supply Company, were grown at three different CO2 levels. The plants were grown in grown chambers set to a 16-hour photoperiod at 10,009 p.p.m CO2, 430 p.p.m. CO2, and 250 p.p.m. CO2. The median value acted as the control because it was the closest to ambient levels. Epidermal peel slides were prepared using fully expanded leaves from each plant. Five lower epidermis and two upper epidermis peels were preformed for each plant using colorless nail polish and tape. Photographs were taken of each slide, and stomatal density was calculated for each growth condition based on the upper and lower epidermis stomatal numbers. These values were compared for any significant differences.

Research Highlight: Shannon Baldwin
“Analysis of Ginsenosides in Commercial Ginseng Products “

Ginsenosides, belonging to a family of steroids, have been isolated as active components in ginseng. Many actions of these ginsenosides have been documented, and ginsenoside composition varies greatly across and even within ginseng species. Several ginseng products currently on the market were extracted and analyzed for ginsenoside concentrations using HPLC technology. Preparations included a range of liquid and powder supplements from Korean, American, and Siberian ginseng products. A similar study of ginseng in commercial products was published by Harkey et. al (2001) before the most recent dietary supplement regulations were in effect. The results of this study indicated that at the time there were considerable differences between the measured concentrations of marker compounds and labeled concentrations. Furthermore, this difference was most noted in liquid products as compared to powdered supplements. This research would offer a view of the impact of recent regulations on a representative sample of ginseng products currently available.

Research Highlight: Michael Harris
“Enzymatic Analysis of the Lancelet Hepatic Cecum” 

Lancelets are members of subphylum Cephalochordata. They possess a notochord but not a spine, making it a close relative of vertebrates. As such, lancelets are an excellent model for studying vertebrate evolution. One of the more interesting evolutionary structures of lancelets is the hepatic cecum. The known function of the hepatic cecum is nutrient uptake, similar to the vertebrate small intestine. It has been hypothesized, though, that the lancelet’s hepatic cecum is the evolutionary precursor to the vertebrate liver. The hepatic cecum is developmentally similar to the liver, developing as an anterior out-pocket of the digestive tract. It has also been shown to perform functions similar to the liver, such as glycogen storage. Recent studies have found that the lancelet hepatic cecum is responsible for the production of vitellogenin yolk protein precursor, which is also performed by the liver in vertebrates. The current investigations sought to compare the enzymes of the hepatic cecum to those found in the livers of primitive fish, specifically whether these enzymes were present in a single form as an isozyme or in multiple allozyme forms. This comparison was done by studying the banding patterns after performing cellulose-acetate gel electrophoresis on lancelet tissue samples and subsequently staining the gels for the appropriate enzymes. Lactate dehydrogenase (LDH), Alcohol dehydrogenase (ADH), and malate dehydrogenase (MDH) enzymes were studied. Our studies found some enzymes of the hepatic presented similar banding patterns to those found in the livers of lamprey while others were absent. This provides some support to the hypothetical relationship between the lancelet hepatic cecum and the vertebrate liver, but also indicates a distant relationship between the two.

Research Highlight: Sarah Twitty
Soil-Dwelling Parasitic Helminthes of the Southeastern United States” 

Nematodes outnumber all other multi-cellular animals. A fist size soil sample may contain thousands of soil-dwelling nematodes, many of which are parasitic to animals and humans. The lifecycles of many parasitic helminthes contain a soil-dwelling stage, usually either an embryonated egg or larval stage. These stages wait in the soil for an opportunity to infect their proper host, either by being ingested or by directly migrating through the host’s skin. Most of these worms do not have a specific definitive host in their life cycle, but are able to infect virtually any mammal, and sometimes birds and reptiles. Once inside the definitive host the parasites grow, mature, and reproduce. The fertilized eggs are then passed outside of the host in the feces, where they wait in the soil to begin another round of the life cycle. The Southeastern US provides an excellent environment for these soil dwelling stages because the warm, moist climate extends the time that these parasites can survive outside of the host. Some of the parasites that are found in Southeastern Soil are Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis, Ancyclostoma duodenale, Necator americanus, and Strongyloides stercoralis. Because these parasites can be found in the southeastern United States, our goal was to determine which of these are found in the soil in particular environments of Clinton, South Carolina. To accomplish this we took soil samples from four different environments, including two residential yards, a farmland field inhabited by livestock, a young succession field and an old growth forest. DNA was extracted from the soil samples and tissue samples using commercially produced kits. PCR was then performed on the isolated DNA using primers purchased from Invitrogen, Inc. These primers were species-specific (for each species listed previously) based on known DNA sequences taken from published sources and blasted in GenBank, an online resource that libraries DNA sequences from a variety of organisms. The PCR products were then subjected to agarose gel electrophoresis and subsequent ethidium bromide staining to determine if the species of parasite was present in the soil sample. The primers did not amplify the expected PCR product in any of the extracted DNA from the soil samples using the primers for Enterobius vermicularis and Trichuris trichiura, showing that they were not present in any of those locations. The expected PCR product was yielded from the Ascaris lumbricoides primers in the extracted DNA from the young succession field and the expected PCR product for the Ancyclostoma duodenale primers was detected in the extracted DNA from the residential yards, indicating their presence in each.

Research Highlight: Jared Dickerson
“Developmental Stages of the Brown Trout, Salmo trutta”

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The embryonic development of Brown trout, Salmo trutta was observed using fixed embryos, and a series of photomicrographs were produced that show the normal stages of embryogenesis. These photomicrographs were taken with a compound microscope and the scanning election microscope. This study resulted in a series of images that can be used to compare abnormal against normal morphology of the embryos throughout hatchery culture of brown trout. These micrographs highlight structures that are present at certain developmental stages and show the emergence of such structures as the optic cup, lens placode, otocysts, fin-folds, mandible, gill bars, neuromasts and the sensory lateral line.

Research Highlight: Danielle Gill
“A survey and environmental assessment of the dinoflagellates of the middle Pleistocene Camelot Locality”

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Recent sediment sampling at the Camelot site by Beaty in the summer of 2006 and subsequent early analysis seems to indicate that 2 environments may be represented at this site, a freshwater and a saltwater component. At least some of the dinoflagellates may be saltwater types, and may also be Eocene in age (which are the age of the sediments which underlie the Camelot sediments). The research that I will be doing this semester will focus on identifying as many different types of dinoflagellates as possible using light and electron microscopy, and categorizing them using standard keys and online resources to try to determine what percentage of the dinoflagellates are freshwater, and what percentage are basically re-deposited material from the underlying Eocene sediments. There has also been the discussion of the possibility that there was an ocean level rise at the time of Camelot, which would be another possible source for the saltwater component, but this has largely been dismissed based on the sediments. However, if we find that some of the saltwater types are Pleistocene in age vs. Eocene, the idea of sea-level rise during this stage of the Pleistocene would have to be reconsidered.

Research Highlight: Amy Grove
“Analysis of Competition in Freshwater Mussels as a Function of Gill Structure “

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My research involves the comparison of gill structure in two species of freshwater mussels, both existing in large numbers in Duncan Creek, Laurens County, SC, that appear to be in competition with one another. Light microscopy and scanning electron microscopy are being used to obtain details of their filtering apparatus. Two other bivalve species will be compared as possible controls. Hopefully gill structure will provide an answer as to whether or not these species are actually competing for the same food supply, or whether they are simply collecting food from two different food sources. This study will complement another where the size of food uptake is actually measured by using polystyrene beads of known sizes as a surrogate food source for these mussels.

Research Highlight: Claire Hann
“Developing a series of ˜Carnegie Stages” for human embryos after week 12 of development.”

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Carnegie stages of human embryonic development provide a standard for measuring body proportions in the human fetus between the 2nd and 12th week of gestation. These standards, used in conjunction with ultrasound, allow obstetricians to gauge normal growth in-utero. However, Carnegie stages are not established for gestation following week 12. My project involves taking measurements of body proportions on human embryos from week 12 through week 23 of embryogenesis, and will produce a guide for measuring normal development where the Carnegie stages end.

Research Highlight: Thomas Knackstedt
“The Genetic Mutations of Cohen’s Syndrome”

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The purpose of this research project is to investigate the genetic nature of Cohen’s syndrome and to establish a list of mutations and their associated symptoms. Cohen’s syndrome is a rare autosomal recessive disorder that has just recently been recognized as a genetic disorder and consequently very little research has been done on it. I was made aware of the disorder during my internship at the Greenwood Genetics Center in the fall of 2006. All 62 exons of the COH1 gene responsible for Cohen’s will be investigated through a PCR amplification followed by a determination of the nucleotide sequence in control DNA and that of patients suffering from Cohen’s syndrome. A better understanding of the genetic background of Cohen’s syndrome will be of major importance to its effective treatment.

Research Highlight: Ashley Ragan
“Particle Capture Ability of Freshwater Bivalves “

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My research focuses on the relationship between the structure and function of freshwater bivalve gills. Using fluorescently-labeled microbeads as an artificial food source, the ability of various freshwater bivalves to capture certain size particles will be determined and compared to the known ultrastructure of ostia on the frontal surface of the gills. This research will hopefully elucidate any niche partitioning that occurs between various species of freshwater bivalves and provide some insight to the rapid spread of the introduced Asiatic clam.

Research Highlight: Benjamin von Schweinitz
“Effectiveness of Expired Antibiotics”

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The purpose of my research is to look at the effectiveness of antibiotics that have passed their expiration date. This experiment comes out of my interest to look at ways to curb the ever-rising cost of health care. While drug companies stand to lose money if the dates are extended, consumers will benefit is they are allowed to use the growing stockpile of older medication. The research involves taking commonly prescribed antibiotics such as Amoxicillin and performing a Minimum Inhibitory Concentration (MIC) test. The MIC analysis uses known concentrations of an antibiotic and evaluates its ability to kill particular bacteria.

Research Highlight: Laurel Hickman & Erica Raheja
The PC Biology Department was awarded another contract from The Tennessee Wildlife Resources Agency which allowed one PC student, Laurel Hickman, to work as a summer intern with Dr. Bob Hudson, conducting research in freshwater mussel ecotoxicology. This research involved toxicological testing using freshwater mussel juveniles which were artificially cultured in the laboratory. This research ultimately leads to cleaner water, helping governing officials set proper safe levels for many river effluents. Furthermore, Dr. Ron Zimmerman and Dr. Hudson had one Governor’s School Student (Erica Raheja) who worked on a six-week internship investigating the effect of immunization on success of mussel larval attachment on fish. Finally, Erica attempted inoculation of mussel larvae on different species of fish in an attempt to determine which species have the highest transformation success.