Undergraduate Research Program

Lauren Saulino is working with Dr. Michael Childress in the Department of Biological Sciences on red swamp crayfish, Procambarus clarkii, which have a ritualized style of fighting to minimize the energetic cost and risk of injury when competing over resources such as food, shelter and mates.  Previous studies have found that fights between familiar crayfish have a reduced number and intensity of aggressive acts suggesting that recognition of previous opponents influences crayfish behavior.  What is unclear is whether crayfish learn to recognize all dominant opponents or only those they have previously encountered.  Lauren tested these hypotheses by pairing crayfish in brief fights with individuals of similar size and sex.  If crayfish have a generalize dominance recognition, Lauren expects to have a reduced number and intensity of aggressive acts and she expects subordinate individuals to avoid shelters with the odor of both familiar and unfamiliar dominant opponents.  If, however, crayfish have individual dominance recognition, Lauren expects to have a high number and intensity of aggressive acts and she expects subordinate individuals to avoid shelters with the odor of familiar dominant opponents only.

Lindsey Olmstead is working with Dr. Julia Frugoli in the Department of Genetics, Biochemistry, and Life Science Studies on research to develop transgenic Medicago truncatula plants (a model legume) that carry a reporter gene that will allow visual measurement of auxin concentration (a plant hormone crucial to a number of plant developmental processes) within the plant using DR5::GUS.  This reporter gene generates a blue color in areas of high auxin concentration  when the plants are treated with a chemical (MUG).  Lindsey is investigating the expression pattern of the DR5::GUS construct in the supernodulation mutant sunn and the nodulation defective mutant pdl to look for differences between wild type plants and these mutants.  The reporter plants will thus allow us to visually observe auxin levels during the various stages of the nodulation process in M. truncatula, both in the wild type and in mutant plants.

Brittany Dettman is working with Dr. Xiuping Jiang in the Department of Food Science and Human Nutrition on bacterial resistance to ceftriaxone, an antibiotic used in humans to help fight infectious diseases caused by gram-negative bacterial pathogens.  It has been hypothesized that the use of ceftiofur, an antibiotic structurally similar to ceftriaxone in food-producing animals, could be a possible source of theses antimicrobial resistant strains.  In this research, the effect of treating calves with ceftiofur was studied by identifying the ceftriaxone-resistant bacteria in the calves' feces and determining the degree of resistance in these bacteria through various tests.  Current results have shown that calves treated with ceftiofur have shed significantly high numbers of ceftriaxone-resistant bacteria in feces.  Brittany began work on this project as part of the Summer Program for Research Interns Program two summers ago and has continued her work as a freshman at Clemson.

Jennifer Page is also working with Dr. Julia Frugoli in the Department of Genetics, Biochemistry, and Life Science Studies on research to develop transgenic Medicago truncatula plants (a model legume) that carry a reporter gene that will allow visual measurement of auxin concentration (a plant hormone crucial to a number of plant developmental processes) within the plant using DR5::GUS.  This reporter gene generates a blue color in areas of high auxin concentration when the plants are treated with a chemical (MUG). Jennifer is investigating the expression pattern of the DR5::GUS construct in the supernodulation mutant skl and the nodulation defective mutant lin to look for differences between wild type plants and these mutants.  The reporter plants will thus allow us to visually observe auxin levels during the various stages of the nodulation process in M. truncatula, both in the wild type and in mutant plants.

Catherine Ridings is working with Dr. Jim Morris in the Department of Genetics, Biochemistry, and Life Science Studies on research to remove the Hexokinase 1 gene in Trypanosoma brucei, the organism that causes African sleeping sickness in humans.  This metabolic gene has been identified as playing a role in the regulation of surface molecule expression by sensing conditions in the parasite’s environment.  Once the gene is removed, the parasites will become a valuable tool for further dissecting the pathway that links metabolism and surface molecule expression.

Kimberly Doering is also working with Dr. Jim Morris in the Department of Genetics, Biochemistry, and Life Science Studies on research to identify the mechanisms that the African trypanosome uses to regulate surface molecule expression.  We have identified a peptidyl prolyl cis-trans isomerase (PPIase) that is essential for surface protein expression through an RNA interference-based genomic library screen.  We hypothesize that PPIase, which catalyzes the cis-trans configuration of proline residues, is critical for the successful folding and expression of this parasite’s proline-rich major surface glycoprotein.  In this project, Kimberly will use RNA interference to silence expression of PPIase to determine its role in surface glycoprotein expression, which we will assess by flow cytometry.  Additionally, she will express and purify recombinant PPIase for use in enzyme assays to explore possible substrate preferences and for the generation of polyclonal antibodies for localization studies. 

Willie M. Greggs III is working with Dr. Margaret Ptacek and her graduate student, Shala Hankison, in the Department of Biological Sciences on research to test the behavior of two mollies species, Poecilia petenensis and P. mexicana.  This study looks at the color preference of both male and female individuals of these species. These data will help determine and identify certain genetically controlled behaviors as a response to specific environmental cues, in relation to color.  During testing, fish are placed in a tank and tested for their preferences for eight differently colored disks (red, yellow, orange, green, blue, purple, white and black).  Preference is determined by time spent in close proximity to a disk (specified zones around the colored disks) and pecking at the colored disks.  This data will help determine which color(s) are preferred by Poecilia petenensis and P. mexicana.  This research is part of a larger study that is investigating the evolution of color preferences in live-bearing fishes, and how these preferences might relate to mate choice.

Megan Harvey is also working with Dr. Margaret Ptacek in the Department of Biological Sciences on hybrid research.  Hybrid individuals often occur under laboratory conditions but because of isolating mechanisms, hybrids are not usually found in the field.  Recently, however, two putative Poecilia hybrids between a sailfin molly, P. velifera or P. petenensis, and a shortfin molly, P. mexicana were collected in Campeche, Mexico.  Megan used both morphometric as well as genetic analysis of the specimens to determine their hybrid status.  For morphometrics, several aspects of the dorsal fin of the putative hybrids were intermediate between the sailfin and shortfin except dorsal fin height.  Genetic results showed that one of the putative hybrids, MP 225, contained the fragment from both P. mexicana and P. velifera. The other putative hybrid, MP 226, contained only the P. mexicana fragment.  Further characterization of MP 225 using DNA sequencing of the mtDNA control region indicated that the maternal origin of the hybrid is P. mexicana.  In continuing research, Megan is determining the paternal sailfin species, P. velifera or P. petenensis, by sequencing a unique nuclear region.

Jonathan Babb is working with Dr. Kerry Smith and Dr. Cheryl-Ingram Smith in the Department of Genetics, Biochemistry, and Life Science Studies to investigate the catalytic mechanism of acetyl-CoA synthetase (ACS), the principal enzyme for the conversion of acetate to acetyl-CoA. Acetyl-CoA, an essential intermediate in numerous metabolic pathways, is a key precursor in the synthesis of many important biomolecules such as fatty acids, cholesterol, and some amino acids. The primary aim of this research project is to determine what amino acids are involved in binding CoA, one of the substrates for ACS. Two specific arginine residues have been targeted for analysis. These residues have been altered to alanine and the resulting enzyme variants will be analyzed kinetically. CoA analogs and the technique of chemical rescue will be used to elucidate the specific role of each arginine side chain in the binding of CoA. The results of this project will contribute to a greater understanding of the biochemical characteristics of ACS and will ultimately provide insight into the biochemistry of other ACS-related enzymes.

Jaime Cyphert is working with Dr. William Marcotte in the Department of Genetics, Biochemistry, and Life Science Studies to investigate the role of specific angiosperm seed proteins in the acquisition of desiccation tolerance. As part of the normal developmental program, most seeds experience severe dehydration yet obviously remain viable. In addition to representing the connection between successive plant generations, seeds are also the primary source of protein for human nutrition, either directly through products derived from legumes and cereal grains (e.g. beans/peanuts and breads/pastas, respectively) or indirectly through livestock feed. Work is currently focused on the characterization of mutants in the model plant system Arabidopsis thaliana that no longer express one or more of the proteins associated with desiccation tolerance to detemine the effect(s) on seed development and viability. The mutants will also provide a means for the eventual establishment of protein structure-function relationships.

Rosanna Robertson is working with Dr. William Marcotte in the Department of Genetics, Biochemistry, and Life Science Studies to investigate the use of traditional crop plants (e.g. tobacco) for the production of novel protein biopolymers. Plants represent highly evolved protein factories. With the decline in tobacco use in the United States and worldwide, alternative uses for this readily-cultivated crop plant will be important for the farming community. The proteins present in Nephila clavipes (spider) dragline silk are serving as a model for these studies. Spider dragline silk is a strong, elastic, waterproof, stretchable, biodegradable, natural b-sheet protein polymer. This project is part of an interdepartmental collaboration in which the group's objectives are to develop clonal production of fiber forming protein polymers by genetic expression in yeast and plants, and (2) understand arachnid biology of silk production to lay the foundation for the development of biomimetic protein fiber spinning. The ultimate goal is to express these synthetic genes in transgenic organisms in order to obtain sufficient quantities of recombinant protein for fiber and film production.

Stephanie Stutts  is also working with Dr. Michael Childress in the Department of Biological Sciences on the Caribbean spiny lobster, Panulirus argus.  Some species of spiny lobsters are gregarious and share crevice shelters with conspecifics while other species are asocial and live alone.  Panulirus argus is gregarious, but the spotted spiny lobster, Panulirus guttatus, is not.  Both species occupy coral crevices in the Florida Keys but differ in their initial settlement habitat.  P. argus settles in sea grass with a high density of conspecifics.  P. guttatus settles on coral reefs with a low density of conspecifics.  Stephanie hypothesized that conspecific density during early development influences spiny lobster gregariousness and can explain the den sharing differences observed between these species.  To test this hypothesis, newly settled P. argus and P. guttatus were be raised under two different social conditions, in isolation or with four conspecifics.  After two months individuals were tested for their attraction to familiar and unfamiliar conspecific odors.  The results will help determine if these differences in the behavior of adult lobsters are influenced by early social experience and/or individual recognition of familiar conspecifics. 

Jennifer Enfinger is working with Dr. Andrew Mount in the Department of Biological Sciences on research involving the movement of oyster blood cells in the Eastern oyster, Crassostrea virginica. Two functions attributed to oyster blood cells, also known as hemocytes, are immune defense by phagocytosis and shell formation by crystal deposition.  Common to both functions is chemotaxis, which is the cell’s ability to follow a chemical gradient that emanates from either the infection site or from the biomineralization front.  She hypothesizes that these blood cells will be chemotactic for certain peptides such as fMLF and for materials present in the shell such as collagen. This research is important because hemocytes exhibiting chemotaxis suggests that oysters have a complex cellular immune system that may serve as an excellent model to study immune system evolution throughout the animal kingdom.