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Abstracts

Author Department ↑ Professor Title Year
Danielle M. Rosen Biology Anne Casper Effects of Fragile Site FS2 on Mitotic Crossovers in the Yeast Saccharomyces cerevisiae
While crossovers during meiosis are encouraged, mitotic crossovers can cause loss of heterozygosity and sometimes lead to tumorogenesis and are therefore suppressed. It is hypothesized that mitotic crossovers result from the repair of double strand breaks in the DNA. Specific loci called fragile sites are more susceptible to DNA breaks under replication stress. FS2, a common fragile site in the yeast Saccharomyces cerevisiae, is susceptible to breaks under low levels of DNA polymerase. This study will be the first to investigate whether fragile site breaks stimulate mitotic crossovers. Through analysis of single nucleotide polymorphisms that alter restriction sites, we will determine the sites of the crossovers. We predict that mitotic crossovers will occur more frequently when cells are under replication stress created by low levels of polymerase alpha, and these crossovers will occur as a result of double strand breaks at a common fragile site (FS2) in S. cerevisiae.
2011
Prannda Sharma and Christine Mella Biology Aaron H. Liepman Visualizing the AtCSLA1 and AtCSLA14 Gene Expression Patterns in Arabidopsis thaliana Using Promoter:GUS Reporter Gene Fusions
Plant cell walls are an important renewable resource used to produce fuel, paper, textiles and many other products. Despite the importance of cell walls, there still is much to learn about the identities and functions of proteins that are responsible for cell wall biosynthesis. Several genes in CELLULOSE SYNTHASE-LIKE A (CSLA) subfamily encode for mannan/glucomannan synthase enzymes, proteins that produce mannan polysaccharides of cell walls. Our objective is to determine the expression profile of all nine CSLA genes present in Arabidopsis thaliana at various stages of growth and development using CSLA promoter:GUS analysis. The expression patterns of CSLA genes will be compiled into a gene expression map that will be used to determine where and when these genes are expressed. Moreover, this study will aid future efforts to functionally characterize these genes using reverse genetics. Here, our progress analyzing the AtCSLA1 and AtCSLA14 genes is presented.
2011
Stephanie Simon Biology Daniel Clemans and Steven Pernecky Interactions between Probiotic Bacteria in the Production of Lactate and Butyrate
Short chain fatty acids have been shown to have a positive impact on the human immune system and on gastrointestinal health. The purpose of the experiment was to characterize and quantify short chain fatty acids (butyrate and lactate) in in vitro cultures of gut bacterial cells. Quantifiable amounts of short chain fatty acids were detected by GC-MS, and bacterial cell numbers were determined using quantitative PCR (QPCR). The ratio of cell number to short chain fatty acids specifically was determined by QPCR. The interplay between short chain fatty acid precursors and producers will be characterized by studying probiotics under variable cell growth conditions. The methods can be used to determine the factors that influence the production and fate of short chain fatty acids that are potentially beneficial to one's health.
2011
Mary E. Skinner, Evan R. VandenBosch, Prannda Sharma, Adnan K. Syed, Danielle M. Rosen, Yvonne Kang, Alexis I. Stein, and Christine Mella Biology Aaron Liepman Characterization of the Expression Patterns of CELLULOSE SYNTHASE LIKE A (CSLA) Genes in Arabidopsis thaliana
The walls surrounding plant cells serve important physiological functions creating structure, providing defense, and enabling cell signaling. Plant cell walls also are the largest source of renewable biomass, with many practical applications including food, building materials, and biofuels. Plant cell walls consist primarily of carbohydrates, including cellulose, hemicelluloses, and pectins. Mannans are hemicellulosic polysaccharides with cellular functions including structure, storage, signaling, and possibly other functions. Numerous members of the CSLA gene family encode mannan synthases (enzymes involved in mannan synthesis). This project aims to create an expression atlas that documents the expression pattern for each of the nine CSLA genes in the model plant Arabidopsis thaliana by using GUS-reporter gene fusions. The atlas will be used to identify focal points for characterizing mannan patterning and abundance using fluorescence microscopy. Understanding the synthesis and patterning of mannans will enhance our understanding of the roles of these polysaccharides in plants.
2011
Jamie N. Slater Biology Robert Winning and Geoffrey Murphy A Novel Transgenic Mouse as a Model of Age-Related Cognitive Decline
It is estimated that 40% of people over the age of 65 experience age-related cognitive decline that impacts quality of life. With an increase in the aging population, this is an important issue to address. A number of biological pathways are thought to contribute to age-related cognitive decline, including the up-regulation in L-type voltage-gated calcium channels (LVGCC). To determine the relative contribution of LVGCC up-regulation to age-related cognitive, our laboratory has developed a transgenic line of mice that over-express an LVGCC in the forebrain. We anticipate that the over-expression of LVGCCs in young animals will mimic the cognitive impairments observed in aged mice. We present a molecular characterization of this new line of mice. In the future, these mice will be used as a model of aging. This project will contribute to research leading toward development of pharmaceutical therapy to alleviate the symptoms of age-related cognitive decline in affected individuals.
2011
Himabindu Anumala Chemistry Cory Emal Design, Synthesis, and Evaluation of Non-Symmetric Small Molecules for the Enhanced Inhibition of PAI-1
Plasminogen activator inhibitor-1 (PAI-1), a primary inhibitor of both tissue-type and urokinase-type plasminogen activators in plasma, is a well-established risk factor in various disease conditions. Increased levels of active PAI-1 in plasma are correlated with the development of atherosclerosis, diabetes, stroke, and other maladies. In the present study, we describe the synthesis of new series of compounds that aim to reduce physiologically active PAI-1 levels. These molecules are related to a series of bis-arylsulfonimides and arylsulfonamides connected by short linking diamines. These studies resulted in the identification of small molecule inhibitors of PAI-1 that displayed in vitro IC50 values in the low micromolar range.
2012
Architha Ellenki Chemistry Deborah Heyl-Clegg The Effect of Incorporated Cholesterol on Disruption of Model Membranes by hIAPP
Human Islet Amyloid Polypeptide (hIAPP) has been implicated in Type II Diabetes development. The extent of membrane disruption and the presence of amyloidal clusters on the surface of pancreatic _-cells reflect the severity of the disease. The development of Type II Diabetes increases with age, and age effects changes in cell membrane structure. Cholesterol is believed to inhibit hIAPP permeabilization of POPG model lipid membranes. Contrary to our hypothesis, liposome dye leakage experiments on DOPC/DOPS model liposomes in our study demonstrate that with elevated membrane-incorporated cholesterol levels and increased hIAPP concentrations, membrane disruption actually increases. These results will lead to further studies to attempt to correlate other membrane changes with a cell's susceptibility to hIAPP.
2012
SaiDeepthi Illendula Chemistry Lynn Shetron Short-Chain Fatty Acid Production by Microbial Organisms in a Bioreactor
Short-chain fatty acids (SCFA) such as butyrate and lactate are the products of colonic bacterial degradation of starch and other carbon sources important in human health. Prior work has indicated that SCFA production in the microbiota is markedly affected by interaction of the organisms in the microbial community. The time courses of butyrate and lactate production during growth of the organisms in a bioreactor are being investigated to permit a meaningful analysis of microbial biochemistry. The goal of the research is to investigate the extent to which physical contact of microorganisms and/or shared biochemical pathways for production of SCFA are responsible for the dramatic changes in lactate or butyrate concentrations in media that occur when they are co-cultured in vitro.
2012
Anupama Jasthi Chemistry Deborah Heyl-Clegg and Hedeel Evans Using Peptides to Examine an Interface Between Two Pyrimidine Pathway Enzymes in Aquifex Aeolicus
Pyrimidine nucleotides play a critical role in cellular metabolism by serving as activated precursors of RNA and DNA. Aquifex aeolicus encodes pyrimidine pathway proteins homologous to those found in mesophilic organisms. The aspartate carbamoylase (ATC) domain catalyzes the second step in the pathway forming carbamoyl aspartate that is then converted by the dihydroorotase domain (DHO) to dihydroorotate. The DHO and ATC domains from A. aeolicus were overexpressed in Escherichia coli and purified by affinity chromatography. The X-ray structure shows that E193 and G194 on the DHO domain are residues that might be critical for interaction with the ATC. I used enzyme kinetics to test the functional significance of this region in the presence of a peptide synthesized to mimic a loop on the DHO.
2012
Theodora Katsika, Santita Campbell, Jacinda Lisi, and Ebaa Saad Chemistry Ellene Tratras Contis and Jose Vites The CSIE Program at EMU: Positive Impact in Recruitment and Retention of STEM Students
The Creative Scientific Inquiry Experience (CSIE) program uses an innovative approach to address the decreasing success rates of undergraduate students in STEM (Science, Technology, Engineering, and Mathematics) fields. In this study, we evaluate the impact of CSIE strategies on retention and graduation rates of STEM students. We identified 71 CSIE students enrolled in STEM classes in the fall of 2006 and compared them to 882 non-CSIE students enrolled in the same classes. The CSIE cohort had higher chances of remaining as a STEM major and higher graduation rates. Interestingly, CSIE students were more likely to convert to a STEM major by graduation time. Qualitative and quantitative results will be presented to support the success of the CSIE program in improving recruitment and success rates for EMU STEM students.
2012
Nirosha D. Perera Chemistry Hedeel Evans Purification of FAM129B, a Currently Identified Protein that Is Important for Cell Invasion, in E. Coli
Metastasis is the result of the disruption of the precise balance between proliferation and apoptosis. It has been estimated that up to 90% of metastatic tumor cells are lost by apoptosis. Thus, approaches that can tip the balance in favor of apoptosis would be expected to be effective in combating proliferative disorders. FAM129B is a currently identified protein that is important for cell invasion.). It has a pleckstrin homology domain near the amino end and a proline-rich region near the carboxyl end. One crucial facet of the mechanism through which FAM129B promotes cancer cell invasion is likely to be the suppression of apoptosis. We have purified the FAM129B protein in E. coli by affinity chromatography and are characterizing its properties by gel filtration chromatography and its ability to interact with key proteins.
2012
Steve R. Spaulding Chemistry Maria Milletti Computational Study of PAI-1 and Some of its Inhibitors
Plasminogen Activator Inhibitor-1 (PAI-1) plays a key role in the inhibition of fibrinolysis, the process by which blood clots are broken down. In many cases it becomes necessary to increase the rate of fibrinolysis. One way that this can be accomplished is by inhibiting PAI-1. Previous research has shown that polyphenolic compounds can be effective inhibitors of PAI-1. In this work, Density Functional Theory was used to model several inhibitors in the PAI-1 binding site in order to better understand the interaction between inhibitor and protein. A Natural Bond Orbital (NBO) analysis is used to analyze the strength of the interaction within the binding site.
2012
Christina A. Varney Chemistry Ruth Ann Armitage Characterizing Organic Colorants in a 15th Century Iranian Timurid Qur'an by Direct Analysis in Real Time Time-of-Flight Mass Spectrometry
The Islamic Department at the Detroit Institute of Art has in its possession a 15th-century Iranian Timurid Qur'an. This manuscript is the subject of a multidisciplinary study that includes identifying the materials used in the construction as well as its cultural and historical significance. EMU is utilizing direct analysis in real time mass spectrometry to identify the dyes, binders, pigments, and inks of the Qur'an. Mock samples were made using materials from the period and region of the manuscript. The manuscript itself is Middle Eastern in origin but with Chinese artistic influences, so materials from both regions are being used. The mock samples contain a combination of dyes, binders, and lead white. The different combinations will end up as a database of spectra that can be compared to the real sample spectra when it is run.
2012
Nadine C. El-Ayache Chemistry Cory Emal Design and Synthesis of Bis-arylsulfonamides and Aryl Sulfonimides as Inactivators of Plasminogen Activator Inhibitor-1 (PAI-1)
PAI-1 is a naturally occurring serine protease inhibitor involved in the inhibition of urokinase- and tissue-type plasminogen activators. At physiological levels, PAI-1 takes part in many processes, such as cell migration, fibrinolysis, angiogenesis, and wound healing. At pathological levels, PAI-1 has been linked to renal disease, obesity, deep vein thrombosis, type 2 diabetes, cardiovascular disease, cancer, and pulmonary disease. Therefore, synthesis of potent and specific PAI-1 inhibitors is of great importance. A variety of aryl sulfonamides and aryl sulfonimides were synthesized, and their potencies as PAI-1 inhibitors were determined. Based on the data collected, a structure-activity relationship model has been developed.
2010
Reshma Kankanala Chemistry Hedeel Evans Characterizing the Oligomeric Structure of the Dihydroorotase and Aspartate Transcarbamoylase from the Bacterium Bacillus anthracis
Bacteremia is the bacterial invasion of the blood. Bacterial proliferation in the blood requires that the organism adapt its metabolism to available nutrients. Nucleotides precursors that could be used are present at very low levels in the blood, and thus the invading bacteria must rely on de novo nucleotide biosynthesis for survival. The dihydroorotase domain is a key enzyme in pyrimidine biosynthesis and catalyzes the third step in the pathway. It was recently shown to be a promising drug target since defects in this enzyme caused an approximate 1000-fold decrease of viable cells in the blood. We cloned the genes encoding the dihydroorotase and aspartate transcarbamoylase from the bacterium, Bacillus anthracis, and expressed them in Escherichia coli. The proteins were purified by affinity chromatography and their oligomeric structures determined by gel filtration and cross-linking methods. The oligomeric structures were determined in the presence and absence of substrates.
2010
Mahalakshmi Kotichukkala Chemistry Hedeel Evans Interaction of Carbamoyl Phosphate Synthetase with Other Components of the Pyrimidine Pathway in Aquifex Aeolicus
Aquifex aeolicus, an extreme hyperthermophile, encodes proteins that are homologous to the major carbamoyl phosphate synthetase (CPSase) domains found in mesophilic organisms. The CPS.A and CPS.B homologs from A. aeolicus were overexpressed in Escherichia coli and purified to homogeneity by affinity chromatography. Previously, it was found that a stable 124-kDa complex could be reconstituted from stoichiometric amounts of CPS.A and CPS.B proteins that synthesized carbamoyl phosphate from ATP, bicarbonate, and ammonia. In this study, the purified carbamoyl phosphate synthetase components were tested for their binding and interaction with the aspartate transcarbamoylase and dihydroorotase domains, the enzymes that catalyze the next reactions in the pathway. The interaction was tested in the absence and presence of the substrates and at different temperatures. Enzymatic assays to determine the outcome of protein-protein interaction on the catalytic activity of each component were also carried out to investigate putative functional linkages.
2010
Ran Li Chemistry Ruth Ann Armitage Characterization of the Binders in the Rock Art of Cueva La Conga, Nicaragua
Archaeologists want to know if the paintings in Cueva La Conga, the only recorded painted cave in Nicaragua, were influenced by the Maya, Caribbean cultures, or were a purely indigenous development. Using radiocarbon dating to determine the age of the paintings will help to understand the possible cultural relationships between known cultures and the rock art. The prerequisite for radiocarbon dating using accelerator mass spectrometry is that an organic binder must be present in the painting samples and is extracted and dated later. We are using thermally assisted hydrolysis/methylation-gas chromatography-mass spectrometry (THM-GC-MS) to study the composition of the paints to determine if any binder material remains. Comparing the compositions of the paint and unpainted limestone will allow us to determine if a reliable date is likely to be obtained. We will describe the inherent difficulties of reconciling good analyses with preservation of these irreplaceable and at-risk cultural materials.
2010
Rajani Maddi Chemistry Steven John Pernecky GC/MS Characterization of Short Chain Fatty Acids in in vitro Microbial Culture Systems
Butyrate and lactate are naturally occurring short chain fatty acids (SCFAs) produced by probiotic bacteria that reside in the human gut. These chemicals play a vital role in the maintenance of colonic health. In vitro cultures of probiotic bacteria containing single and combined cultures producing lactate and butyrate provide an opportunity to determine how bacterial interaction affects butyrate and lactate production. To conduct our studies, anaerobically cultured probiotic bacterial samples were obtained from Dr. Clemans (Eastern Michigan University). The cultures were subjected to C-18 column extraction followed by ether extraction. Quantitative measurement of lactate and butyrate was performed on the extracts after chemical derivatization and analysis by GC/MS. Our experimental results revealed that the combined cultures of probiotic bacteria produced a measurable amount of butyrate compared to single cultures. Detection limits were such that butyrate levels in biological samples could appropriately be determined.
2010
Mace R. Mattieson Chemistry Heather Holmes On-Trap Derivatization of Short-Chain Fatty Acids
It has recently been hypothesized that gastrointestinal microbiota modulate immune response by the production of short-chain fatty acids (SCFAs). There is a need for rapid, selective analytical methodology capable of trace analysis of SCFAs in complex biological matrices. Preconcentration of SCFAs has been demonstrated with gas and liquid chromatography using multibed-sorbent traps, solid phase microextraction (SPME), and on-fiber derivatization with SPME. This project incorporates the use of 1-pyrenyldiazomethane (PDAM) as a derivatizing agent immobilized on graphitized carbon beds in a multi-bed sorbent trap. The goal is to achieve low ppb-range detection limits for SCFAs using headspace-gas chromatography with flame ionization detection. Isobutyric acid at a concentration of 100 ppb has been detected without derivatization at this point in time.
2010
JoLisa McDay Chemistry Heather Holmes Ecological Method Development for Detecting N-Nitrosodimethylamine in Water Using HPLC-PDAD
Using ethanol, a sustainable reversed-phase high-performance liquid chromatographic method with photo-diode array detection (HPLC-PDAD) was investigated to detect sub-parts per billion concentrations of N-nitrosodimethylamine (NDMA) in drinking water and environmental water samples. This presents a practical and 'green' option to analytical methods that require laborious derivatization, expensive detectors, and unecological solvents. Mobile phase characteristics, instrument operating parameters, and sample preparation were investigated. Selectivity for NDMA was evaluated using three different C18 columns. Optimal peak resolution and detection were achieved at 231 nm. The limit of detection and quantitation for NDMA was 0.29 _g/mL and 0.96 _g/mL, respectively, with an ethanol modifier and 5-?m column. A sustainable solid-phase extraction method was also investigated. Using ethanol for cartridge conditioning and extraction, recovery of NDMA was low (10%).
2010

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