Research Mentors & Projects
My research investigates the neurobiology of sexual motivation. I use an animal model to study how motivation for sex interacts with drugs of abuse. I focus on female sexual motivation in rats to better understand motivation in general as well develop potential treatments for sexual dysfunction in women. In addition, I have a line of research that researches issues of reproductive success and sexual selection in rats.
In 1967, Garcia and Koelling demonstrated that rats could learn to associate an audio-visual stimulus with electric shock, but could not associate the same stimulus with illness. In contrast, rats could associate illness with sucrose flavored water, but could not associate sucrose with shock. These results were quite surprising at the time and led to a substantial literature on biological preparedness. In two separate experiments, we plan to extend this literature to goldfish. The “average predator,” obtained by morphing 64 digital photos of known predators will serve as the conditioned stimulus (CS). When this CS is paired with a live largemouth bass we expect the association to be made quickly. However, when the “Average Predator” is paired with food, the association should be made slower, if at all. Control conditions include unpaired groups of the groups above and paired and unpaired presentations of the “average predator” whose facial features have been scrambled. If successful these experiments will extend the literature on biological preparedness and demonstrate that goldfish view the “average predator” as a threat.
Ampullariids, the family commonly referred to as apple snails, comprise an intriguing group of species from biodiversity and ecosystem function perspectives. The family Ampullariidae includes the largest freshwater snails and represents a major component of tropical/subtropical freshwater biodiversity. Potential projects in the lab range from ecological investigations of life history characteristics (behavior, reproduction, desiccation tolerance, feeding habits) to molecular ecology projects focused on distribution and diversity of apple snails across native and exotic ranges.
Martín Gonzalez & Stacie Brown
The research in our laboratory looks to address the posttranscriptional regulation of the error-prone DNA polymerase V (RumA’2B) from the Integrative Conjugative Element R391. We will be assessing two genes encoded on this element that likely factor in proofreading function of the DNA polymerase V and the selective degradation of RumA’2B.
The Georgetown salamander (Eurycea naufragia) is rare aquatic species known from only 16 sites in the Georgetown area. All known populations of the salamander are threatened by increasing urbanization, and the species was recently listed as threatened under the Endangered Species Act. This project will continue the long-term research and monitoring of two populations of salamanders that my students and I have conducted over the past 7 years. Students will conduct monthly field studies at the two sites, counting and capturing salamanders. We will photograph all salamanders captured and will utilize pattern-recognition computer software to uniquely identify salamanders based on melanophore patterns on the head. From the photographs and field data we will determine salamander abundance, movement, reproduction, and growth rates within these two populations. This information will be used to develop a long-range conservation plan for the species.
Chemistry & Biochemistry
1) This project is designed to explore the possibility that a malignantly transformed cell line might respond differently to the stress of nutrient deprivation than its parental, non-transformed cell line. These cells are grown in culture conditions where nutrient availability can be controlled, and the responses of the cells can be studied by detecting the appearance of certain cellular proteins that indicate either an apoptotic (programmed cell death) or autophagic (self-eating) response. Some preliminary studies suggest there is a basic difference in how these cells respond to limited nutrient availability.
2) We have designed several peptides to synthesize and test for their antimicrobial properties. We used clues from the structures of naturally occurring antimicrobial peptides in the design of our synthetic peptides, but we have introduced some structural alterations to change or enhance some of their physical or chemical properties. Some of the alterations include the use of unnatural amino acids in the structures, cyclization of some peptides through chemically reactive side-chains, and modifying the amphipathic nature of the peptides by acylating the amino termini of some peptides with short-chain carboxylic acids. In previous studies with similar peptides, we observed antibacterial activities against some Gram-positive species.
Our laboratory investigates new methods and strategies toward the synthesis of complex organic molecules. First, dialkyltitanium(IV) derivatives are proposed to react with α-halo ketones and aldehydes to produce cyclobutanols. The high strain energies of these organic moieties can be exploited in the synthesis of complex organic molecules of biological, agricultural, and industrial importance. Furthermore, because of their 1,2-dianionic nature, dialkyltitanium(IV) species are anticipated to react with a variety of other electrophiles to form five- and six-member rings. With support from the Welch Foundation, we have already laid the groundwork for the formation of cyclobutanols and are currently optimizing conditions and testing the scope the reaction.
We are also developing a gold-cleavable protecting group for use in organic synthesis. Alcohol protecting groups allow synthetic chemists to manipulate functional groups on complex molecules without detrimental side-reactions resulting from deprotonation. Unfortunately, methods to remove common protecting groups often involve harsh conditions that are not compatible with sensitive functionality. Our protecting group is proposed to be stable to acidic and basic conditions but is easily removed under mild gold-catalyzed conditions. We have already synthesized and applied the protecting group to simple organic molecules and plan to begin optimizing the cleavage reaction. Pre-requisites: At least one year of Organic Chemistry at SU.
Several gold(III) and copper(II) complexes have shown potential for cleaving DNA upon irradiation. These findings will be explored further during the Scope Summer Research Program. Specific focus will be on investigating the mechanism by which cleavage occurs and on the binding selectivity of these complexes. The gold(III) complexes, in principle, have the capability to bind covalently to DNA. This potential will also be investigated, and kinetics of such binding will be studied for those are found to bind to DNA in such manner.
We will be synthesizing a semicarbazone and thiadiazole ligand this summer to react with select transition metals to form organometallic complexes. Those complexes will be characterized using NMR and IR and, if crystals can be grown, x-ray diffraction. We then plan to conduct biological testing using DNA or bacteria to determine any potential biological activity.
DNA damage is thought to play a role in many human age-related diseases such as cancer, cardiovascular disease, and neurodegeneration and can arise from both exogenous factors and endogenous processes. The goal of this project is to evaluate the ability of antioxidants to protect DNA from DNA damage induced by free radicals. In another project, we will be measuring DNA damage levels in brain tissue of rats exposed to a widely abusive drug that binds to dopamine receptors, leading to the formation of reactive radicals. Pre-requisites: At least one year of General Chemistry at SU. Organic Chemistry preferred.
Our primary project will focus on understanding how the timing of a dolphin kick affects performance in a breaststroke pullout. However, we will also have the opportunity to continue investigating the effect starting block design on start performance and we may undertake some work on applying some waveform analysis techniques to examine the forces generated in competitive swimming strokes.
Since ventilatory rate can affect speech pattern, it has long been suggested that the disruption in speech pattern might be a practical means of determining the ventilatory threshold. With this idea in mind, an application for the iPhone/iPad is being developed that will be able to quantify speech pattern disruption. Repeating a common phrase into an iPhone/iPad at specific times across the duration of an incremental exercise bout should allow for plotting a pattern of disruption that could possibly identify the ventilatory threshold. This project will seek to determine if speech analysis during incremental exercise can provide a valid and reliable means of determining the ventilatory threshold.
“Comparison of Calorie-counting vs. Self-evaluation Methodology” is a study that will examine 2 currently popular, nutrition for weight loss techniques. Students will get to work hands on with human subjects attempting to lose weight and will learn to evaluate body composition, blood pressure, blood glucose, various diet regulation techniques, and how nutrition can impact weight loss.
The topic of difference equations is not covered in the typical undergraduate curriculum, and yet some is accessible to a motivated student with a solid high school math and science background. Difference equations lend themselves to study at a variety of levels; some work can be accomplished with a high school background, and yet advanced mathematics can also be included. This type of mathematics lends itself well to inquiry-based and interdisciplinary research by undergraduates.
My project has two major goals. The first is to build an autonomous vehicle that can travel over rough terrain for several days and take measurements during that time. The second is to use input from a camera to recognize the shape and color of the item using machine learning (an artificial intelligence algorithm).