OMEA Honors Capital University's Jim Swearingen for Distinguished Service
23rd annual Dr. Martin Luther King Jr. Day of Learning January 20
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Acid mine drainage (AMD) effects can be found in many waterways in the United States. Streams found near mining sites have exceptionally low pH and increased concentrations of heavy metals. In this project, water and soil samples were taken at various locations along the West and Main branches of Sunday Creek in southeastern Ohio. Nearby mining operations have been inactive for recent years but AMD still occurs as a result of precipitation runoff of gob piles and accumulation of uncontaminated water in subsidence holes. The goal of the project was to determine if the water chemistry of Sunday Creek is improving with time and remediation efforts. The samples were tested to determine the concentrations of iron and manganese using atomic absorption spectroscopy. Results indicate that one of six sampling sites has significantly higher levels of contaminates. Results correlate with the EPA data from the summer of 2001. Soil samples were taken from the creek bed and surrounding area to be analyzed for iron and manganese, to develop a correlation between both metals in the water and soil. Source water concentrations of metals can fluctuate constantly, while the soil gives us a more accurate result to support data collected from water.
The state of an electrode surface can have dramatic effects on the oxidation-reduction activity of solution species. Selective modification of the surface enables one to have control or study these effects. One common method of electrode modification is through covalent attachment by diazonium ion reduction. The result is a near monomolecular layer of specific molecules at the electrode surface. The chemical functionality of the diazonium ion serves as the selectivity component of the electrode. An interesting question is whether asymmetric polar molecules produce unique electrochemical results due to steric hindrances or molecular alignment. The synthesis, isolation, and characterization of five diazonium ions [benzene diazonium, 4-nitrobezene diazonium, 2-nitrobenzene diazonium, 2-(trifluoromethyl) benzene diazonium, and 2-(trifluoromethoxy) benzene diazonium] from their amine precursors is presented. The diazonium ions are isolated as tetrafluoroborate salts. The chemical functionality of the diazonium ions vary from polar to nonpolar, as well as symmetric to asymmetric. Additionally, initial electrochemical results of electrode modification using the synthesized diazonium salts is presented.
Myocilin is a protein closely linked to inherited forms of glaucoma, a neurodegenerative disorder associated with increased intraocular pressure. In myocilin, over 90% of reported glaucoma-causing missense mutations are localized to the C-terminal olfactomedin (OLF) domain. To determine the relative stability of wild-type and mutant OLF, we developed a fluorescence thermal stability assay without removal of MBP. The fluorescence thermal shift assay can accommodate relatively low concentrations of protein and uses a qRT-PCR instrument to conduct a slow melt while measuring fluorescence. The excitation and emission settings of the RT-PCR instrument are compatible with Sypro Orange, a dye known to bind to hydrophobic regions of proteins. Given upper and lower limits of the fluorescence signal, a melting point can be determined as the midpoint of the unfolding transition. We expressed and purified the OLF domain of myocilin and select glaucoma mutants (D380A, I477N, I477S, K423E) as MBP fusion proteins. Compared to wild-type, all MBP-OLF mutants tested were destabilized but retained a discrete melting transition. Our study appears to be a novel application of the fluorescence stability assay to a MBP fusion protein and lays the foundation for the identification of tailored therapeutic molecules to delay the onset of glaucoma.
Ion Selective Electrodes (ISEs) are used to detect the presence of specific chemical species in aqueous solutions. ISEs are popular as they exhibit a linear response (on a semi-logarithmic plot) over several orders of magnitude in concentration changes for the selected species. In addition, ISEs are appealing for field research due to the fact that they are robust and compact. Near the lower concentration limits of detection, however, the response becomes non-linear and quantification becomes difficult, presumably where the effect of other ions (including H3O+ and OH-) become significant. In this study, a nitrate (NO3-) ion selective electrode was quantified using a series of standard solutions. Standard addition and sample addition methods were explored to determine if better quantification can be achieved by shifting low concentration samples into linear portions of the response curve prior to measurement. Results have thus far been inconclusive as signal variation has been greater than expected and negatively impacted the precision of the method. Despite this, the method shows promise and this presentation examines current results and future approaches to improve measurement precision.
Nitrate ion (NO3-) is a nutrient pollutant found in waterways near agricultural, industrial, and sewage waste areas. If consumed, concentrations in excess of 10 ppm can cause illness in children under the age of six months. Samples from the Tuscarawas River were taken near the Newcomerstown Waste Water Treatment Plant. Using an ion selective electrode and a standard addition method, these water samples were analyzed for NO3- concentration. Data show a NO3- concentration range of 0 to 1.377 downstream and a range of 0-5.160 upstream. These results suggest contamination from the waste water treatment plant. At the point source where waste is released into the water, NO3- concentration ranges from 0 to 7.699 ppm. This concentration is not harmful to humans if consumed.
The ability to read and comprehend the primary literature is an essential skill for college graduates in any scientific field and is emphasized by both the American Society for Biochemistry and Molecular Biology and the American Chemical Society. However, explicit teaching of this skill rarely occurs in the college classroom. The POGIL (Peer Oriented Guided Inquiry Learning) teaching style can be easily adapted to include activities which require the students to read and study the primary literature. These activities allow the professor to instruct the students, both directly and indirectly, in how to read the primary literature. Preliminary data show an increase in both student comfort with the primary literature and confidence in their ability to understand articles. The data support the students’ increased ability to read and comprehend the primary literature. Such findings support the use of POGIL methods in college education as effective.
The dimensions of an electrode can greatly affect the current response towards electroactive species. As the physical dimensions become smaller, mass transport of species to the electrode surface transitions from a linear to a radial regime. A Microelectrode Array combines the benefits gained from smaller electrode size with overall activity similar to larger electrodes – resulting in signal to noise enhancement and lower detection limits. Chromium species are well known to act as corrosion inhibitors as they form insulating layers on surfaces. The layers formed are exceedingly thin (less than 10 nanometers), but effectively block electron transfer shutting down electrochemical reactions. In this study chromate ion (CrO42-) is attached to an electrode surface by using increasingly dilute solutions of CrO42- to form an incomplete barrier. The resulting electrode surface should be a mixture of insulated and conductive sites. However, the conductive sites of the electrode may act as individual microelectrodes that can approximate an electrode array. If successful, this approach could prove to be an alternative to more difficult photolithographic methods that are currently used. The experimental approach and initial results of this investigation are presented.
A protocol for Biochemistry Laboratory (Chemistry 452) at Capital University was previously designed for the purification of riboflavin binding protein (RBP). The protein, which is found in chicken eggs (it is actually in both the whites and the yolks, we just use the whites), was purified and a new protocol was developed to examine the temperature−based unfolding and refolding process. Riboflavin fluorescence is 100% quenched when bound to the protein. As the temperature increases the protein begins to unfold and the riboflavin is released from the protein and begins to fluoresce. It was determined that RBP is completely unfolded at 80°C by monitoring the increase in riboflavin fluorescence. Upon cooling, the fluorescence intensity drops to near zero, suggesting the protein correctly refolds. The thermal unfolding protocol used in the experiment was successful as well as unique and will be implemented in future biochemistry laboratories courses.
RNA processing in archaea is similar to that in eukaryotes and therefore serves as a simple model for eukaryotic systems involving tRNA modifications. In the halophilic archaeon Haloferax volcanii (Hvo.), the enzyme tRNA intron endonuclease is known to cleave precursor tRNAs at a specific structural motif. The focus of the research is to advance understanding of RNA processing. To accomplish this goal, pre-tRNA-Gln(CCA) was subjected to cleavage by tRNA intron endonuclease to determine optimal reaction conditions. Intron endonuclease cloned from Hvo. and pre tRNA-Gln were purified using affinity chromatography and in vitro transcription. Cleavage reactions were conducted in which KCl and MgCl2 concentrations and incubation times were varied. Reaction products were compared using Northern blot analysis to determine the amount of cleavage. Optimal cleavage conditions appear to be 40 mM Tris-HCl pH 7.4, 2% glycerol, 20 mM MgCl2 and 2 M KCl. The endonuclease activity is not sensitive to moderate pH changes or MgCl2 concentration between 5 mM and 50 mM. Ionic strength is important with increasing activity observed at higher KCl concentrations from 200 mM to 2M KCl and no cleavage observed below 200 mM KCl. Varying conditions to determine optimal cleavage will allow for additional exploration of substrate specificity including RNA sequence variation and addition of RNA binding proteins. This work will lead to a better understanding of tRNA processing in archaea.
Surface water surrounding the Alum Creek Combined Sewer Overflow (CSO) in Bexley, Ohio was analyzed for nitrate (NO3-) and phosphate (PO43-) ions. This study is significant because the City of Columbus plans on spending $2.5 billion to reduce the effect of CSOs in local waterways. Water sample testing using an ion selective electrode and the standard addition method from four locations surrounding the CSO shows an increase in the nitrate and phosphate levels from upstream to downstream. Preliminary analysis for nitrate shows that the concentration upstream from the CSO was 3.9 ppm NO3-, and at the last tested location downstream it had risen to 4.6 ppm. The EPA sets a maximum contaminant level of 10 ppm nitrate ion in drinking water, so with an actual overflow, the concentration of nitrate could be hazardous if consumed. Preliminary analysis for phosphate shows a concentration of .162 ppm PO43- at the CSO, while the concentration was 0.0285 ppm upstream and 0.00711 ppm downstream. Phosphate levels in natural water are considered dangerous when exceeding 0.1 ppm PO43-. The phosphate concentration at the CSO is already above this limit.
The Chemistry Department at Capital University has been using Peer Led Team Learning (PLTL) workshops to provide students the opportunity to gain a further understanding of chemistry through active learning. In order to enhance these workshops, three different games were developed as aids to memorization for three different classes: Chemistry 101, Chemistry 131, and Chemistry 231. To determine the effectiveness of the games as learning tools and to gauge student opinion, the different games have been assessed using a pre-test and a post-test on the topic covered by the game played, as well as a student opinion survey. Data analysis to date show that over 80% of students who played the games felt that doing so contributed to their learning. This suggests that the Chemistry Department should continue using PLTL games.
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