Research Presentations - 2005
John Deere Chapter of Sigma Xi

7:00 - 9:30 pm, Wednesday, November 30, 2005
Science Building Room 102, Augustana College, Rock Island, Illinois
Parking is available in Lot H, just north of the building.  You may enter on the ground floor at either the north or
 south entrance.  The lecture hall is at the south end of the building.  There is handicap parking at the north entrance.

Below is the list of talks and posters that will be presented by the new associate members of the chapter inducted on October 18.

The talks will all be in Room 102.  During the evening, the posters will be on display in the Atrium of the Science Building.  The students displaying posters will be introduced at 8:45 pm in Room 102.  At 8:50, in the Atrium, we will have refreshments, view the posters, and enjoy conversation with all of the presenters.

It has been determined that enzymatic recycling reactions coupled together can amplify a measurable product by which the levels of L-glutamate can be accurately measured using spectrophotometry. The purpose of this experiment was to verify this by replication of the experiment done by Valero and Garcia-Carmona, and build upon the methodology to make any realistic improvements. The experiment was duplicated, yielding a direct correlation between the levels of absorbency and the L-glutamate. It was hypothesized that a stopping reagent could be added after a certain time to stop the change in absorbency, which would to a degree eliminate the time factor yet still enable an accurate way by which to detect low levels of glutamate. Several stopping reagents were tested, however, HCl was the best stopping reagent. This was then added to different concentrations of L-glutamate after a certain time, revealing an almost identical direct correlation found in the original experiment. More tests will need to be done to verify the accuracy of this method in cells.

This experiment was conducted in partnership with Nicholas Rutkowski, who graduated from Augustana last year, as an independent study course. The object of the research was to determine what effect, if any, musical stimuli of varying tempo would have on a human subject's heart rate. Twenty undergraduate students enrolled at Augustana took part in this experiment as part of a Human Physiology laboratory exercise. Heart rate was recorded with three electrodes via a Biopac® computer interface and the subjects listened to the musical selections through headphones. Each subject then listened to two fast tempo songs followed by two slow tempo songs, with periods of silence intermingled. Three of the subjects' data could not be analyzed because of excessive movement, which drastically disrupts the ECG measurements. The seventeen remaining participants' heart rates were measured every twenty seconds throughout the entire 1180 second long recording and averaged.

Spirophenol is an optically active molecule that could potentially be used in the synthesis of liquid crystals. An improved synthetic route for this compound has been found, and methods of purification of the racemic mixture have been established. However, a liquid crystal sample must be enantiomerically pure in order to accurately determine its properties. A chromatographic chiral separation of spirophenol has been achieved, setting the stage for further exploration of the molecules that can be synthesized from it.

The Eastern Kingbird is an aggressive flycatcher spread widely across the continental United States. It uses a variety of foraging methods, most notably aerial hawking. The interest of this study was the frequency of foraging as well as the distribution of different substrates used by the bird. Birds were observed opportunistically throughout the day in five open field/savannah areas. Perch height, perch duration, substrate used, time of day, and number of foraging attempts were recorded for each bird observed. Periodic temperatures were also obtained during each day of the study. Results showed that Eastern Kingbirds preferred perch heights between .5-1 meters. Ranges of 0-.5 and 1-2 meters were next, followed by a range of above 2 meters. Foraging rates were fairly consistent throughout the study and averaged out to be 3.13 minutes/attempt. Perch duration varied widely from a few seconds to six or seven minutes.

Sinorhizobium meliloti is a bacterial strain that has a symbiotic relationship with alfalfa (Medicago sativa) in which it enhances the nitrogen fixation of the plant. The protein SyrA in S. meliloti upregulates several symbiotically-important genes. We utilized SyrA's upregulation of the formation of exopolysaccharides and the sulfation of lipopolysaccharides (LPS) to understand the function of SyrA as a transcriptional regulator since its structure suggests it's a transmembrane protein. In order to do this we isolated mutations of syrA that affected its function. We completed a phenotypic selection using a mutator strain of E. coli to identify plasmids with altered forms of syrA. These plasmids were then conjugated back into fusion strains of S. meliloti in order to identify functional mutations through various assays and SDS gel electrophoresis. Once plasmids with functional mutations were isolated, the mutated genes were sequenced for further analysis.

The Knight lab studies rabbit B cell development and has discovered that two specific bacteria, B. subtilis and B. fragilis, together, can induce gut-associated lymphoid tissue (GALT) formation. My project involved Toll-like receptors (TLRs), which recognize molecular patterns associated with microorganisms. We studied TLR expression in rabbit GALT by looking at various tissue sections and using the method of in situ hybridization in order to investigate the possible involvement of TLRs in bacteria-induced GALT development.

As part of the Interdisciplinary Summer Undergraduate Research Program at the University of Iowa, I investigated a zebrafish (Danio rerio) mutant called crestfallen, which affects normal dorsal neural tube and melanocyte formation. I first determined various first-pass primers to use that encode for the twenty-five chromosomes of the zebrafish based on previous data and internet databases. For the genetic mapping project, I extracted and prepared DNA from zebrafish embryos, made mutant and wild-type DNA pools, used a thermal cycler to amplify the DNA through the Polymerase Chain Reaction (PCR), and performed gel electrophoresis. I ran the samples using gel electrophoresis before using the Quantity One computer program to photograph the gel and compare banding patterns of a control, two mutant pools, a wild-type DNA pool. Further stages of the project include higher resolution mapping and phenotypic analysis.

Efficient glutamate biosynthesis depends on movement of a-ketoglutarate from the mitochondria to the cytosol. The activity of a pathway sensitive to glutamate levels was examined in Saccharomyces cerevisiae with mutations in mitochondrial transporters suspected of carrying a-ketoglutarate. The genes for four transporters (ODC1, ODC2, YMC1, YMC2) were disrupted to create a double mutant strain (odc1D, odc2D) and a quad mutant strain (odc1D, odc2D, ymc1D, ymc2D). Retrograde signaling (RTG) is a pathway activated in response to decreased cellular glutamate levels due to mitochondrial dysfunction. Since inhibition of these transporters decreases glutamate levels, we hypothesized that RTG activity should be increased in the mutants. A gene targeted by the RTG pathway is the CIT2 gene, which encodes peroxisomal citrate synthase. A construct with the CIT2 promoter fused to the lacZ gene was used to observe changes in RTG activity. The data obtained indicate that impaired transport of a-ketoglutarate across the mitochondrial membrane does affect RTG signaling.

Previous theories suggest that an equal investment in male and female function leads to optimal fitness returns. However, certain environmental conditions may create a tradeoff between competition for mates and inbreeding avoidance, which then may favor a deviation from this equal ratio. The present study tested the hypothesis that D. pulicaria will produce the sex underrepresented in their environment, despite a cost of inbreeding depression. Specific questions addressed were: (1) Can D. pulicaria skew the sex-ratio of their offspring based on the sex and kinship of the individuals around them? (2) Does a trade-off between competition for mates and inbreeding depression exist in D. pulicaria?

"Whip-poor-will Call Times/Duration of Calls"
Matthew Bambrick
Green Wing Environmental Lab, Dr. Steve Hager.

The Whip-poor-will has a very distinct call that almost anyone can pick out if they were to sit and listen for it. I chose to take this very distinct call and see if it had an average length and an average time of night when the calls were heard. To do this I used a stop watch and recorded the call lengths of the Whip-poor-will calls detected. The research for this project was done at Green Wing Environmental Laboratory (an Augustana College field station just east of Amboy, Illinois). There were six different locations inside of the Green Wing complex where Whip-poor-will calls and call times were obtained. The results of the research proved fairly inconclusive due to the fact that there was not enough replication. However, the call times did follow a very distinct pattern of hearing the last call every morning around 5 am, and hearing the first call of the night just before 9 pm.