Below is a list of titles of research projects conducted by MARC/AIM scholars in 2005. Click on each title to see an abstract of that project and the names and locations of the scholars and the faculty, staff and graduate students who mentored them. If you scroll down past the list of titles, the abstracts are arranged in alphabetical order of the MARC/AIM participants.
John David Adame, University of Texas Pan-American, Andrew Marky, College Misericordia, Professor Angus S. Murphy, Wendy A. Peer, Bakhtiyor Yakubov, and Anindita Bonyopadhyay, Department of Horticulture
The ability to produce transgenic plants has greatly influenced the study of gene function. In order to analyze gene function, it is crucial to determine both gene expression and sub-cellular localization. Promoter- gene fusions in various reporter lines are widely used for this purpose. Fusion proteins can be used both to transform plants and generate stable transgenic lines, and for transient expression assays. N-terminal and C-terminal constructs were engineered in bacterial (PUC19) and plant transformation (pGREEN) vectors by fusing Arabidopsis aminopeptidase (APM1) to Red Fluorescent Protein (RFP), Yellow Fluorescent Protein (YFP) and HA-TAG under 35S-CaMV or native promoters. P35S constructs will be transiently expressed in onion epidermal cells by a particle bombardment. pGREEN constructs will also be used to transform plants and generate stable transgenic lines. Localization of the reporter tagged proteins will be localized by Confocal microscopy. Expression patterns of the gene will also be analyzed using Promoter-GFP fusion lines. Gene expression in response to various environmental factors will be studied. Screening will then proceed with some of the promoter and gene fusion lines. The site of protein expression or localization suggests its' possible function in an organism. Transgenic lines expressing fluorescent proteins as well as transient assays with reporter fusions of the gene of interest influence the study of the function of a gene. By exposing these plants to different environmental factors, the response of the GUS and GFP lines will be analyzed.
The Effect of the State of the Economy on the Enrollment in MBA Programs
Diana Agidi, Ohio Wesleyan University and G. Logan Jordan, Associate Dean for Administration, Krannert Graduate School of Management
Application to and enrollment in graduate business programs has undergone significant swings in demand over the last several years. After a large increase in the 1990s, enrollments have fallen some 20% year over year in the last several years. Such large swings in demand make it difficult to manage and staff quality academic programs. The Graduate Management Assessment Test is a test intended to provide admission officers with one predictor of a candidate's performance in graduate school. The GMAT test is required by many programs, and as such is an excellent predictor of overall student demand. This research focuses on creating an economic model to help predict the number of people take the GMAT every year. This model will use major macro economic indicators to estimate the number of test takers. The primary independent variables to be considered in this model are the changes in GDP growth rate, Consumer Price Index, Producer Price Index, budget deficit/surplus and the unemployment rate. Data was collected for the period between 1982 and 2003. Data for the number of GMAT test was obtained from the Graduate Management Admission Council. Economic indicators data was obtained from the Economic Intelligence Unit (EIU) country data, the Bureau of Economic Analysis and the Congressional Budget Office websites The relationship between the dependant variable and the independent variables is a linear one modeled by the equation Y1=ß0+ß1X+ß2 X+ e where the ß's are sample coefficients and e is the random sample error. Multiple regressions is used to account for (predict) the variance in a dependant variable based on linear combinations of independent variables. Multiple regressions can establish that a set of independent variables explains a proportion of the variance in a dependant variable at a significance level (significance test of R-sq) and can also establish the relative predictive importance of independent variables (comparing beta weights). Lagging of independent variables is often necessary in order for the regression model to be able to predict the future--that is, to predict what will happen in period t based on knowledge of what happened up to period t-1.The independent variables are therefore lagged in this model. The independent variables are also tested for multicollinearity to ensure that they are not correlated.
Accurate Modeling of Loss Mechanisms in High Frequency Line of R.F MEMS
Olawale Ajayi, Clark Atlanta University and Professor Dimitrious Peroulis, Department of Electrical and Computer Engineering
The project is expected to describe and validate single- and multiple-layer models of MEMS conductor loss appropriate for high-accuracy application in electromagnetic analysis software. My project focuses on creating a model to validate previous models by comparison of measurement and converged result. To most designers of high frequency, it's understood that loss increases with the square root of frequency due to “skin effect” which occurs at high frequency for good conductor as a result of electric current. In transmitting high frequency, as the frequency increases, the “skin effect” layer of the current gets thinner; also as the current is more restricted to the surface, the resistance increases. The goal of this project is to give analysis of behavior of MEMS materials when high frequency like microwave signal is transmitted through it. We are currently constructing schematic structure of the microstrip line, modeled as two infinitely thin sheets of conductor. One conductor sheet is placed directly on the surface of the substrate to represent the bottom side of the actual metal. The other conductor sheet is placed at the top of the actual metal. For high frequency, when the conductor is thick with respect to skin depth, the two infinitely thin sheets of conductor represent the two skin depth generated sheets of current in the actual conductor. At low frequency, the current simply splits equally between the two infinitely thin-sheets of conductor. Microstrip conductor loss exhibits complicated behavior that is not generally recognized. Specifically, there are three frequency ranges of interest. At low frequency, it's expected that there will be no significant difference in behavior, current is uniform through the entire cross-section of the line, and the line behaves like a resistor. At medium frequency, the edge singularity forms. In this case, current should concentrate on the edge of the line, increasing the resistance. At high frequency, the current should split into two sheets of current, one on top of the line, the other on the bottom of the line. Since microstrip dispersion causes the edge singularity to become larger and current to concentrate on the bottom side as frequency increases, the total resistance increases faster than the normally expected square root of frequency.
Comparing Oil Quality using Different Filters in Real Frying Systems
Davida Alexander, Alabama A &M University and Professor Lisa Mauer, Department of Food Science
Frying oil production and waste is a multi-billion dollar business throughout the world, with snack food sales in the US alone exceeding $19 billion a year. Consumers want consistent and high quality food products which is placing increasing emphasis on food product quality and shelf-life. This is causing the food industry and food services to review their oil use practices. Industrial and food service fryers will need to operate more efficiently and economically. There are different oil-blends used for each product type such as: potato chips, French fries, corn chips, doughnut, chicken, ect. The chemical changes that occur during frying create off flavors and odors in the food systems. Therefore the quality of fried food is directly related to the quality of the oil used for frying. The oil is affected by the moisture in the food, the amount of time and temperatures it's used. It is widely known that frying oil time period of optimum oil quality is much less than the time the oil is used. So, it is desirable to extend the time of optimum oil quality to not only improve overall quality of fried foods, but to also increase process efficiency and decrease waste by extending the use life of the oil. The objectives of this study is to focus on characterizing the stability of selected oils in elevated temperatures conditions and monitoring the effects of filtration on oil quality in real frying systems based on the filter type and time. This filtration system was installed in a food restaurant and oil is collected and sent to Dr. Mauer's lab for analysis. Oil quality is measured by the amount of oxidation the oil has undergone. When fats and oils are exposed to air, water, heat, and trace metals oxidation takes place. This is a nonreversible reaction and the compounds from the reaction causes off flavors and odors. Free fatty acids (FFA) are also measured to read the quality of the oil. Fat and oil is made up of mainly triacylglycerides, which are fatty acids etherified to a glycerol backbone. So the more FFA shows the triacylglycerides have been broken down. There are many methods used for analyzing oil oxidation and FFA like the peroxide value (PV) and iodine value ( IV); but we used a test kit sent from Test Kit Technologies Incorporated. The kit has Veri-Fry reagent gel inside the given vials. The oil is added to the vials that were heated to 65ºC and shaken. Then the vial is centrifuged and read on a spectrophotometer at 610nm. The kit gives information on the amount of free fatty acids in the filtered used frying oil.
Decomposing Rate of Varied Conditions: Observational Study
Roshand Arnold, Patrick Jones, and Professor Ralph Williams, Forensic Science Program and Department of Entomology, Purdue University
Forensic Science is the science of using insects discovered on a decomposing body to determine the time since death. This science helps assist in crime solving when adequate eye witness may not have been available. Although there are many types of insects that manifest on a decomposing body there are two that are of major importance during the crime scene investigation. The first is the Diptera (Blow Fly) which can be seen within 8 hours after a female fly lays her eggs. The maggots then feed on the decomposing body. After feeding the maggots either migrate or are eaten by the second most important insect that feeds on a decomposing body, the beetle. As insects develop from egg to adult, they pass through a series of distinct developmental stages. These stages are recognizable and process at a predictable rate for a given set of environmental conditions. However! , it is hypothesized that given the same weather conditions four bodies encased in clothing, a plastic bag, burlap and unclothed would decompose at different rates. The body temperatures were taken daily and after 10 days of observation it was concluded through the migration and physical appearance of the bodies that a clothed and burlapped body decompose at a faster rate than the body enclosed in plastic and the body unclothed.
Luis Avila, St. Edwards University, Professor Daisuke Kihara, and Bin Li Department of Biological Sciences/Department of Computer Science
Many of the complex biological function are maintained by networks of interactions between proteins. Due to the recent rapid growth of solved protein structures, there are often cases where the tertiary structures of proteins, which are known to dock to each other, are experimentally solved, but the docked conformation of them is not known. Recently, all the interacting protein pairs can be experimentally identified by proteomics type experiments such as the yeast two hybrid systems. Knowing the tertiary structure of a protein complex is important to understand the biological function of the complex and essential to the understanding of residues which are responsible for docking and its function. Computational protein docking prediction is aimed to predict the 3-D structure of a protein-protein complex from the coordinates of its component structures. This project's purpose consisted of benchmarking existing algorithms in order to evaluate their limitations and potentials. In this study, ZDOCK 2.3 was used predict the top 20 complexes of a proteins based on its chain components. In the near future, the results from ZDOCK will be compared with the results from another protein prediction program being developed.
Molecular Characterization of Transgenic Arabidopis Expressing a Virus Protein
Ismael E. Badillo-Vargas¹, Muthukumar Balasubramaniam² and Sue L. Loesch-Fries² ¹Department of Crop Protection, University of Puerto Rico and ²Department of Botany and Plant Pathology, Purdue University
Alfalfa Mosaic Virus (AMV) is a plant virus that affects many crops worldwide (e.g., alfalfa, tobacco, potatoes, tomatoes). AMV-infected plants develop symptoms that range from severe necrosis to mosaic and malformation of leaves, reducing the crop production substantially. The genome of AMV is made up of three different RNA molecules that encode proteins that help the virus to replicate (P1 and P2 replicase proteins), move from infected cells to healthy cells to spread the infection (P3 movement protein), and start the infection process and encapsidate the RNA (CP coat protein). All viruses are thought to interact with their host while suppressing host defense responses and while recruiting host factors to assist with multiplication. To identify host proteins interacting with AMV CP, transgenic Arabidopsis thaliana plants, which are susceptible to AMV, were developed to over-express a STREP-tagged AMV CP along with an herbicide-resistance gene. Host proteins interacting with AMV CP in transgenic plants will be isolated by capturing them along with the CP-STREP and identified. Ten herbicide-resistant plants were analyzed by PCR and only one (#9) was found to contain the CP-STREP transgene. RT-PCR analysis indicated that the CP-STREP transgene was transcribed in transgenic #9; however, Western analysis indicated that the CP-STREP protein was not detectable.
Travis Brandt, University of Texas Pan American, Professor Angus Murphy, and Joshua Blakeslee, Department of Horticulture
The focus of this project is the design and implementation of a system to perform the microdeposition of 20-60 nanoliters of solution onto sub-millimeter surfaces. Accurate application of solution onto apical surfaces is required for studies of transport of radiolabeled substrates in planta. The redesign will utilize a Nanoject Oocyte injector using a multi-scale WPI Micromanipulator, with continuing use of a Florod circuit cutter and a modified x,y table. Testing of various application media (agarose gels, lanolin oil, etc.) will be employed for efficiency of application.
Analysis of cell size and growth rate as determinants of differential gene expression in Leishmania mexicana
Michelle Brooks, University of Georgia, Tim Holzer and Professor James Forney, Department of Biochemistry
Leishmania is a protozoan parasite which causes millions of cases of deadly or disfiguring human diseases each year. It has two primary lifecycle stages: promastigotes which are found in the insect vector and a smaller amastigote form in the mammalian host. Unlike most eukaryotes transcription of the Leishmania genome is continuous and does not regulate the expression of individual genes. As a result gene expression is controlled primarily at post-transcriptional levels including mRNA stability. Previously obtained microarray data show ~100 gene transcripts that are expressed at levels more than 2 fold different between the promastigote and amastigote stages and most of these are upregulated in the promastigote stage. Other work has shown that a dynein-2 heavy chain gene knockout creates a promastigote cell with a physical appearance of an amastigote cell; however, it still expresses at least some promastigote-specific protein markers. Our growth rate analysis has shown that amastigotes have an average doubling time of 18.0±3.40 hours, promastigotes 11.3±0.98 hours, and mutant promastigotes 9.67±0.84 hours. Because the dynein mutant promastigote and wild type promastigote grow at a similar rate and have different cell sizes, we can ask whether cell size influences mRNA stability by using quantitative RT-PCR. If the dynein mutants have a steady-state transcript profile similar to wild type promastigotes this would suggest that cell size is not a factor responsible for the predominance of promastigote-enriched mRNAs found in the microarray analysis. However, if promastigote dynein mutants have a steady-state transcript profile similar to amastigotes, this would suggest that cell size is one factor that influences mRNA levels. Our analysis of regulated mRNA in the Leishmania mexicana dynein-2 mutant as compared with wild type promastigote and amastigote will help evaluate the impact of cell size and volume on mRNA stability.
Paul E. Carey Jr., Purdue University and Professor Kavita Shah, Department of Chemistry
Purdue Cancer Center NCI CURE Program *{A wide variety of diseases have their roots in deregulated G protein activities or have harmful signals conveyed through them. Despite their great potential as drug targets, no active site inhibitors is known to date} The focus of this project is targeted towards the formation of G-protein inhibitors and exploring their effect on the biological roles of G-proteins. IN the first step synthesis of the inhibitors will be accomplished starting from Guanosine. In this synthetic strategy the 2' and 3' hydroxyl groups of the Guanosine will be protected as an isopropyldine acetal followed by the protection of primary amine as phenoxyacetamide. Subsequently the 5'-hydroxy group of the Guanosine will be transformed into an amine group and different classes of inhibitors will be prepared by reacting various aldehydes, acids and sulfonyl chlorides using combinational approach. With these inhibitors in hand, different test including GTP/GDP binding assays will be carried out to establish structure activity relationship.
Of temperature, mice and men: what temperature would a mouse choose to live at?
Erica Davis¹, Joe Garner², Ed Pajor² ¹ Department of Animal Sciences, Alabama Agricultural & Mechanical University ² Department of Animal Sciences, Purdue University
Most facilities house mice at 20-22°C, which is a comfortable temperature for a human being wearing scrubs and a lab coat, but may actually be very cold for a mouse without the benefits of a large body size and clothing to keep it warm. The purpose of this project is to establish a more objective housing temperature for mice by doing the obvious, asking the mice themselves. Housing mice at their preferred temperature should alleviate a serious source of stress and improve the welfare of laboratory mice. We have been performing a simple preference-test. We have connected three standard cages with short tubing, allowing mice to freely travel between the three cages. Each cage is kept in a water bath inside a ten gallon aquarium tank set at three different temperatures (20°C, 25°C, and 30°C). Each tank contains an aquarium heater which heats the water and an aquarium pump which keeps the water circulating within the tank. There are three replicas. Each replica consists of three female and three male mice. Each replica has a learning phase and a test phase. During the learning phase, the first three days of each replica, all three mice are placed in each of the cages and are only allowed explore that cage and the associated tubing for 24 hours. This is done so the mice can experience each cage and temperature before the preference-test. During the preference test each mouse is placed in a different cage and is allowed to roam freely for 72 hours. Mouse behavior is continuously recorded using a time lapse VCR. Throughout the experiment a temperature log is kept to ensure cage temperature isconstant. Data is collected every ten minutes in a 24 hour period. Data collected includes the cage location ( 20°C, 25°C, 30°C, or tubing) and their behavior. We divided the behavior into three categories, active, inactive, and maintenance. Active consists of general locomotion, rearing, and sniffing. Inactive includes sleep, still and alert. Maintenance involves nest building, grooming, feeding, and drinking. Once the data are collected the behaviors and cage preferences of male and the female mice over the course of the day will be analyzed.
Effect of age and weight on muscle fiber differentiation in beef cattle
L. Feliciano-Sanchez, University of Puerto Rico- Mayaguez, R.D. Shirley and R.P. Lemenager, Department of Animal Science
The objective of this study was to investigate the effects of weaning age and body weight on muscle fiber types and sizes. Cattle have only three muscle fiber types: 1) Type I (red); 2) Type 2A, and 3) Type 2B (white). The muscle fiber types are classified according to their metabolic activity and speed of contraction. Glycolytic fibers (2B) are larger in diameter than the slower (oxidative) muscle fibers. Forty Angus-sired steers calves were blocked by birth date and weight (initial BW=497 lb ) to one of four treatments for 60 d: 1) early weaned (150 d) heavy calves (EWHC); 2) early weaned light calves (EWLC); 3) normal weaned (210 d) heavy calves (NWHC); 4) normal weaned light calves (NWLC). EWHC and EWLC were fed a high concentrated diet (NEg = 0.62 mcal/lb; 16% CP; DM basis) while NWHC and NWLC steers were left in the pasture with their dams and normally weaned. Surgical biopsies were obtained from the longissimus dorsi (LD) at 150 and 210 d. Samples of muscles were collected and frozen in isopentane cooled in LN2 for later analysis. Muscle fiber types and areas are being determined from the LD muscle utilizing acid ATPase, alkaline ATPase, and SDH staining methods.
Targeting of His-tagged toxic proteins to FR+ tumors via a Folate-Ni conjugate
Timothy Flewelen, University of North Texas, Erina Vlashi and Professor Phillip Low, Department of Chemistry. Purdue Cancer Center NCI CURE Program
Folate is a small B vitamin required by eukaryotic cells for de novo synthesis of nucleotides. Folate is minimally permeable to the cell membrane because of its chemical structure. Therefore, uptake of folate by cells involves a high affinity receptor (KD ~ 10 nM), referred to as the folate receptor (FR), which favors the oxidized form of folate, folic acid. The high-affinity FR is expressed at high levels mainly on cancer cells specifically epithelial cancers of the ovary, mammary gland, colon, lung, prostate, and brain. Because of the nature of the FR, it is possible to covalently attach a macromolecule to folic acid to be delivered to FR-positive cells in the same manner as its natural substrate. It was my aim in this project to synthesize a Folate-Ni conjugate, which will bind to FR-positive cancer cells, and in turn, associate with a his-tagged florescent molecule (which will eventually be substituted with a his-tagged toxic protein). Solid tumors have proven difficult to penetrate deep enough to eradicate all cancer cells. To remedy this, the his-tagged florescent molecule will be left to diffuse throughout all the tissues including the site of the solid tumor. The folate-Ni conjugate will then be delivered, in hopes that the complex folate-Ni-histidine-fluorophore will form on the surface of FR+ cancer cells, and will subsequently be internalized via endocytosis of the folate receptor.
Bernail Fluellen, Florida A & M University*, Elisa Halim, and Professor Bradley Reuhs, Department of Food Science
Preliminary studies have shown that the survival and/or growth of pathogens in fresh produce is influenced by the organism, product item, and environmental conditions in the field and thereafter, including storage conditions. Escherichia coli 0157:H7 is an important foodborne pathogen, which can grow rapidly in several types of fresh produce. This project involves the construction of bioluminescent pathogenic bacteria that facilitates the visual detection of metabolically active pathogens on fresh produce. Our objective was to see how well E.coli 0157:H7 could grow and survive on carbon sources extracted from produce. In order to observe the metabolic activity of E.coli 0157:H7 in the carbon assay, a luminescent strain with the full lux CDABE gene cassette was used. The carbon sources were inoculated with E.coli 0157:H7 at various concentrations at room temperature and at 37°C. Bioluminescence readings were taken every 2 hours within a 24 hour period. E.coli 0157:H7 utilized each carbon source used. A difference was shown between the sample stored at 37°C and room temperature. Overall, the carbon sources at 37°C utilized E.coli 0157:H7 more, producing more CPS than at room temperature.
Lenese Grant, Alabama A&M University and Professor Lisa Mauer, Department of Food Science
Many powdered substances in the food industry are susceptible to caking, stickiness, and agglomeration. Foods products that exhibit caking include powdered drinks, baby formula, or powdered recipes. These products are not only at risk of caking—they are eventually susceptible to a phenomenon known as deliquescence. Deliquescence is a first-order phase transition from a solid to a solution. An ingredient undergoes deliquescence at a specific relative humidity (RH) that is higher that the substance's stable humidity. The deliquescence point (RHo) can be estimated by water activity readings. Water activity (aW) is measured by equilibrating the liquid phase water in the sample with the vapor phase water in the headspace, thus measuring the RH in the headspace. The purpose of this research is to gain a greater understanding of the deliquescence of select ingredients and ingredient mixtures (binary, tertiary, and quaternary mixtures). Mixtures of ingredients are predicted to deliquesce at lower RHs than the single ingredients. The methods used for this project were an Aqua Lab model 3TE (water activity meter) and desiccators. The Aqua Lab was used to measure duplicate water activities of sodium diacetate, monosodium glutamate (MSG), sodium chloride, and sucrose in single, binary, tertiary, and quaternary mixtures at 25 C. As hypothesized, the aW of the binary, tertiary and quaternary mixtures was substantially lower than the individual components. MSG and sodium diacetate were placed in desiccators with RH ranging from 54% to 94 %. At 54 % RH Na Diacetate experienced little caking and MSG was free-flowing. At 65% RH Na Diacetate was caked and moist and MSG was caked. At 76% RH MSG was caked and Na Diacetate had liquefied. At 84% MSG had caked and Na Diacetate was liquefied. At 94% MSG was slurry (partially deliquesced) and Na Diacetate had completely liquefied. Na Diacetate critical relative humidity was estimated to be around 64% RH, and aW of the saturated Na Diacetate solution was 0.69. Additional studies investigated the effects of temperature on aW of MSG and Na Diacetate saturated solutions. Results showed aW increased as temperature decreased. These results indicated the relative humidities at which sodium diacetate, MSG, sodium chloride, and sucrose should be stored to avoid deliquescence. The results also indicated that Na Diacetate is not a very stable ingredient in foods. When mixed with other foods, it will be even more susceptible to deliquescence. Also, temperature fluctuations will impact the deliquescence behavior of food ingredients.
Mass Spectral Determination of Herbicide and Heavy Metal Contaminants
Erick J. Hurtado, University of Texas Pan American, Professor Angus Murphy and Alfred R. Diggs, Department of Horticulture
Recent epidemiological evidence suggests an increased incidence in gall bladder cancer in dogs due to exposure to lawn chemicals. In an effort to determine risk, a pilot study will analyze dislodgeable residues from lawn surfaces as well as urine samples from both dogs and children in order to determine heavy metal content and the presence of herbicide. A RaPID Enzyme Immunoassay (EIA) was used to test for the presence of 2,4- dichlorophenoxyacetic acid (2-4 D) in grass samples. The presence of Mecoprop (MCPP) was assayed using Liquid Chromatography / Mass Spectroscopy (LC/MS).Current work is focused on standardizing herbicide quantitation protocol analysis.
Gel encapsulated Ped-2E9 cell hybridoma as cell-based biosensor forrapid detection of Listeria monocytogenes and Bacillus cereus toxins
Adrienne Johnson, Alabama A & M University and Professor Arun Bhunia, Department of Food Science
The detection and enumeration of microorganisms either in foods or on food contact surfaces from an integral part of any quality control or quality assurance plan. Microbiological tests done on foods can be divided into two types :(a) quantitative enumerative, in which a group of microorganisms in the sample is counted and the result expressed as the number of the organisms present per unit weight of sample; or (b) qualitative or presence/ absence, in which the requirement is simply to detect whether a particular organism is present or absent in a known weight of sample. The basis of method used for testing of microorganisms in foods is very well established, and relies on the incorporation of a food sample into a nutrient medium in which microorganisms can replicate thus resulting in a visual indication of growth. Such methods are simple, adaptable, convenient and generally inexpensive. However they have two drawbacks: firstly, the tests rely on the growth of organism in media, which can take many days and result in a long test elapse time; and secondly, the methods are manually oriented and are thus labor intensive. Over recent years, there has been considerable research into rapid and automated microbiological methods. This projects' objective is to use collagen encapsulated Ped-2E9 cells for cell based detection of Listera monocytogenes and Bacillus cereus toxins. Ped-2E9 cells which normally grow in suspension would be immobilized and grown in collagen gel in 3-deminsional encapsulated form. Gel encapsulated Hybridoma cells would then be exposed to Listeria monocytogenes and Bacillus cereus toxins of different concentrations. Cytoxicity will be determined by a spectrophotometer.
Pt(II)-trpy complexes: Photoluminescence and DNA Binding Motifs
Olivia Johnson, Purdue University and Professor David McMillin, Department of Chemistry
Platinum(II) polypyridines, specifically Pt(II)-trpy (where trpy denotes 2,2':6'2”-terpyridine), have a special affinity for DNA which could prove to be useful for cancer therapy. Some of these complexes, such as [Pt(trpy)OH]+ have been found to interact with DNA through competitive covalent and intercalative binding modes, in which the planar trpy ligand allows for insertion between base pairs of DNA. Many of the complexes are not emissive in aqueous solution and therefore a valuable technique for DNA probing or tracking is lacking. It is believed that the addition of a cyano (-CN) group to the Pt(II) will impede covalent binding and the addition of an electron-withdrawing or donating group at the 4' position of trpy will greatly increase the photoluminescence of the Pt(II)-trpy complex. The two compounds studied were [Pt(pyrr-T)CN]+ and [Pt(dma-T)CN]+ (where pyrr denotes pyrrolidine and dma denotes dimethylamine) which were both made by a multi-step synthetic reaction. It was observed, with a flourometer, that the photoluminescence of the complexes increased in aqueous solution while the emission of [Pt(pyrr-T)CN]+ with DNA was greater than that of [Pt(pyrr-T)CN]+ due to a longer lifetime. UV-vis spectra showed there was no evidence of intercalation. This may be due to electron cloud repulsions of pyrr and dma with the front face of the DNA. In the spectra, three states of the complex were observed. Further investigation includes: 1. determining if the emission of the complexes with DNA is base sensitive by interacting the complexes with poly(dA-dT)2 and poly(dG-dC)2, 2. observing the possibility of damaging DNA by photocleavage when the complex is associated with DNA.
April Kittel, Grambling State University, Anna Klopot and Professor James C. Fleet, Department of Foods and Nutrition. Purdue Cancer Center NCI CURE Program
The intestine absorbs nutrients from digested food and also serves as a barrier to exclude harmful organisms and substances from our bodies. The cells that line the inside of the intestine are organized into indentions (crypts) containing rapidly growing and dividing cells and projections (villi) containing functionally mature absorptive epithelial cells. While proliferating crypt cells do not absorb nutrients they can differentiate to become nutrient absorbing cells as they migrate up the villi. Our long term goal is to better understand the process of differentiation responsible for the maturation of cells that absorb nutrients and protect the body from harm. This was examined via both a reductionist (one-gene model) and globalist, bioinformatics approach. Tissue specific gene expression examination is traditionally done by conducting studies on representative genes that produce proteins critical for nutrient digestion or absorption (i.e. the Calbindin D9k (CaBP D9k) gene encoding the calcium binding protein that is critical for absorption of calcium from the diet). Previously, reporter gene analysis showed that HNF-1a and cdx-2 control CaBP D9k gene activity during intestinal cell maturation by binding to specific DNA sequences within the CaBP D9k promoter. Currently our lab is studying whether these transcription factors interact with the CaBP D9k promoter in vivo. We tested this by performing Chromatin Immunoprecipitation (ChIP) assays. Initial data shows that promoter regions previously shown to be important using reporter gene assays are associated with acetylated histone H3, indicating that they have an open, transcriptionally active structure in vivo. Since the completion of the Human Genome Project, scientists can now look beyond the single gene approach and examine what happens to all genes during intestinal differentiation. We have examined gene expression patterns in two publicly available microarray datasets: (1) A dataset comparing gene expression along the proximal-distal axis in mouse intestine (duodenum, jejunum, ileum, and colon), and (2) A dataset comparing gene expression along the crypt-villus axis in mouse duodenum. Significance Analysis of Microarrys (SAM version 2.0) computer program was used to identify genes that were differentially expressed in dataset (1). The computer program GeneCluster was used to examine patterns of gene expression in dataset (1) and (2). This analysis revealed genes whose expression is unique to specific segments of the intestine. Future research will examine whether regulators identified as significant for our representative gene (CaBP D9k) are important for the regulation of genes whose expression is unique to the duodenal villus.
Amber Landers, University of California-Riverside and Professor David Rollock, Department of Psychological Sciences
This study examined how stressful police contacts are for African American college students, relative to other stressors. Given the history of relations between law enforcement and communities of color, it was expected that police contacts would be equally or more stressful than other stressors, and that men would score higher than women on stressfulness of police contact. African American undergraduates (66 women, 35 men) completed a questionnaire packet including a stressful life events scale composed of items from existing measures, as well as police items created specifically for this study. Participants rated each item for frequency and stressfulness. Multivariate analyses of variance indicated no main effect for gender. However, means for police stress were lower than means for family, school, romantic, personal distress, and non-police discrimination. The analyses also revealed a significant gender by stressor interaction, suggesting that men reported significantly greater stressfulness of police contacts, while women reported slightly greater stressfulness of other types of situations. Limitations and recommendations for future research are discussed.
Analysis of the Expression of 5'-inositol phosphatase SHIP2 in Lung Cancer
Marie Laoye1, Manish Tandon2 and Professor Nagendra K. Prasad2 1School of Science, Indiana University Purdue University, Indianapolis, Indiana; 2Basic Medical Sciences, School of Veterinary Medicine
Background: Phosphotidylinositol 3'- kinase (PI3K) is an important component of cell signaling pathways relevant to cancer. SH2-containing 5'-inositol phosphatase 2 (SHIP2) down-regulates PI3K signaling, therefore, is a potential regulator of cancer development. Higher level of SHIP2 protein is found in many cell lines derived from the tumors of cervix, breast, colon and lung. In tumor cells SHIP2 promotes cell adhesion and cell spreading on type I collagen. Moreover, SHIP2 inhibits ligand-induced down-regulation of the EGF receptor (EGFR). Aims: We are currently working on a hypothesis that SHIP2 plays a positive role in oncogenesis. Our long term goal is to determine the role of SHIP2 in oncogenic transformation and metastasis. Improper activation of EGFR is a frequent molecular pathology responsible for the development and progression of cancers, and in particular, that of lung cancers. As SHIP2 can influence the levels of EGFR, we will determine if SHIP2 is linked to the development of lung cancer through the oncogenic pathway initiated by the EGFR. To this end, as a preliminary approach, we will examine the expression of SHIP2 in lung cancer. This data will reveal any relationship between SHIP2 and lung cancer providing a solid scientific rationale for the further analyses of the function of SHIP2 in oncogenesis. Experimental design: Five clinical specimens of human lung cancer were analyzed for SHIP2 expression using standard immunohistochemistry procedure in comparison with the normal counterparts. Results/Conclusion: Among five cancer specimens tested, two of the five cancer specimens were positive for expression of SHIP2 while the other three were very weakly positive or negative. Normal lung samples were negative for SHIP2 expression. Additional specimens need to be examined to determine the significance of this observation. Even so, this study provides the basis for further investigation into the proposed link between SHIP2 and lung cancer.
Effects of Copper Stress on Flavonoids in Arabidopsis
Jade Li, University of Texas – Pan American, Wendy Ann Peer, and Professor Angus S. Murphy Department of Horticulture
High amounts of copper are toxic to any plant. Although there are copper tolerant plants, there are no hyper- accumulators of copper. Even for those plants that are tolerant, copper still induces oxidative stress. Flavonoids are widely distributed secondary compounds produced by plants. There is a specific copper binding flavonol, quercetin, which may reduce the effects of copper stress. This flavonol fluoresces gold under UV light. Flavonoid deficient tt3 mutant accumulate 5X more quercetin at the cotyledonary node and 10X more quercetin in the root tip than wild type (Peer et al., 2001). The tt3 mutation is in the Ler ecotype background. Flavonoids are natural antioxidant compounds produced in plants. However, the extent to which flavonoids contribute to plant oxidative stress responses is unclear. It is also not known whether flavonoids respond to the generation of reactive oxygen species (ROS) in plant defense responses. Copper and wounding will be used as elicitors of ROS and the flavonoid responses will be determined. There are two hypothesis to test, if quercetin binds copper as one of the antioxidative mechanisms in plants, then the amount of quercetin will increase when the seedlings are treated with copper, and if quercetin is one of the oxidative stress mechanisms, then there will be less reactive oxygen species (ROS) staining in seedlings treated with copper. The results from flavonoid localization and ROS staining show that since different ecotypes of the plant will have different copper tolerance levels, there are ecotypic differences in quercetin accumulation under stress conditions; from the data collected it is apparent that there are tissues-specific differences in quercetin accumulation under stress conditions; quercetin plays a role as a scavenger of reactive oxygen species after initial oxidative stress.
Simulation Based Analysis of Transport Processes in Plants
Charlotte Lloren, Universtiy of Texas Pan-American, Anne Knoeller and Professor Angus Murphy, Department of Horticulture
Auxin, a plant hormone, plays a major role in establishing the polarity in a plant and is essential for plant growth and development. The exact interaction of how auxin is distributed is yet to be found. To analyze the transport, a simulation-based approach called Agent Based System, ABS, was chosen with focus on auxin transport. The system contains “Agents” with specific features (such as size, weight and volume). These agents act independently and interact with each other and the defined environment they are in. The simulated environment where these interactions occur must be created separately and then combined with the agents later on. Agents, such as types of RNA and protein, have specific characteristics and behaviors that need to be taken into account for the simulation. This project entails the design and creation of a database containing information on the agents to be used for simulation and also query searches. The database should be capable of being extended by way of additions and changes to each agent's gathered information at any time. Data collected will be saved as an XML file, and Java will be used for the user interface.
The Resurrection of the Author: Authorial Presence in Postmodern Metafiction
Ariel Lopez, DePauw University and Professor John Duvall, Department of English
Roland Barthes has proclaimed the author dead, claiming that “writing can no longer designate an operation of recording, notation, representation, ‘depiction' . . . .” According to Barthes, with a postmodern understanding of text and identity, the author has no meaning. I agree with Barthes' assertion that “a text is not a line of word with a single ‘theological' meaning (the ‘message' of the Author-God), but a multidimensional space.” I, however argue that one of these dimensions (and perhaps more importantly, a discernable and analyzable one) is the presence of the author in the text. Even if authorial identity is simply a construct, it then forms another text behind the principal one. However, many authors raise their own authorial identity to the foreground using self-reflexivity and metafiction. In this realm, modes of narrative collide, and authors deliberately reveal their presence. They may play with the ideas of authorship, creation, textuality or readership, but in one way or another they all affirm the role of the author. By examining various postmodern metafictional narratives, including Immortality by Milan Kundera, The Floating Opera by John Barth, various short stories by Jorge Luis Borges, and Roland Barthes' own work Roland Barthes by Roland Barthes, I intend to show how the author that Barthes has proclaimed dead can be resurrected. Many postmodern creators have used a textual self-awareness to comment on and critique their own texts. In her Politics of Postmodernism Linda Hutcheon goes so far as to identify certain types of metafiction as a defining feature of postmodernism. In particular she looks at historiographic metafiction, or “where documentary historical actuality meets formalist self-reflexivity and parody.” This idea of historiography is key, because every text is metafictional in that it is a history of its own creation. Works that explicitly thematize this idea allow insight into the creative process and hence the creator. The idea of pastness with respect to the text as artifact implies a creator existing before the text: “The Author, when believed in, is always conceived of as the past of his own book” (Barthes 224). Attitudes to this pastness vary, from the assumption of John Barth's fictional author in The Floating Opera, that the process of both reading and writing is a purely linear one, to Roland Barthes' own parodic autobiography, which opens at the end of his fictionalized writing process. The self-assessment of writers' authorial status also runs the gamut. On one side, writers such as Milan Kundera powerfully affirm their own status as “Author-God,” explaining the mechanisms of creation, and their own role in those mechanism. At the far other end, are writers like Jorge Luis Borges, whose fictions constantly deny his creator status, he is merely the storyteller or voice of God. Even this denial, however, functions to highlight the place of the creator within the text, once again showing how metafiction refutes Barthes' claim.
Tetradecanoyl phorbol-13-acetate (TPA) induced ornithine decarboxylase (ODC) activity in cultured cell lines as tool for monitoring drug chemopreventive activity
Wilmarie Lorenzo1, Tamara Kondratyuk2, John M. Pezzuto2 1 Department of Chemistry at University of Puerto Rico at Mayagüez, 2Department of Medicinal Chemistry and Molecular Pharmacology. Purdue Cancer Center NCI CURE Program
Ornithine decarboxylase (ODC) is a key enzyme in the biosynthesis of polyamines and is highly inducible by growth promoting stimulli including growth factors, steroid hormones, cAMP-elevating agents and tumour promoters. ODC is considered an attractive target for cancer chemotherapy and chemoprevention. In our program for the procurement of novel plant-derived chemopreventive agents, we have used inhibition of TPA-induced ODC activity in different cell cultures as monitor for chemopreventive activity. These cell lines were ME 308, T24, and JB6. ME 308 is a mouse epidermal cell line, immortalized, nontumorgenic cells, was originally established from Balb/c mouse skin initiated with 7, 12 –dimethylbenz(a)anthracene (DMBA); T-24 a human epithelial cell carcinoma and JB6 a mouse epithelial skin cell line. All three cell lines have ODC activity and to monitor which cells are the best in expression of this activity we tested ODC activity in each listed cell lines, measuring the release of [14C]CO2 from L-[1-14C]ornithine. Our experimental results showed that the best cell line for ODC drug testing is T24 cells. These cells showed time dependence and a maximum activity at 6 hours of incubation. TPA at concentration 200nM activated ODC activity by 378±134 % which allowed us to detect small % inhibition of ODC activity under influence of different compounds under investigation.
Protein Expression Profile in Breast Cancer of African American Compared to Caucasian Women
Krystal Madden1, BS, Olufunmilayo I. Olopade2, MD, FACP, and Sulma Mohammed3, MS, DVM, PhDJackson State University1, University of Chicago Hospitals2, Department of Veterinary Pathobiology3. Purdue Cancer Center NCI CURE Program
Despite the fact that breast cancer incidence rates are higher among Caucasian woman than in African American women, it is much more aggressive and has a higher mortality rate among black women as compared to their white counterparts. In an attempt to understand this phenomenon, researchers have examined these statistics from various angles. Factors such as genetic and environment were thought to contributes to this differences; however, the exact causes of this disparity are not known. In order to stand the basic in breast cancer tumorigenesis in African American women we decided to use a proteomic approach to elucidate this mechanism. The reason is that any cell phenotype is determined by its protein composition and the activation status of its proteins. Two-dimensional gel electrophoresis, protein finger printing, and databases could be employed to determine differences in proteins expression profiles between tumor and normal cells and to identify differentially expressed proteins. Therefore, the purpose of our study is to examine the protein profiles of breast cancer in African American women through a comprehensive investigation of the proteome in normal and malignant breast cancer compared to that of white women. Breast cancer tissues and adjacent normal tissues from black or white women were obtained from Chicago University with approval of Purdue University Institution board review approval. Each sample was prepared from a 100mg-400mg tissue and was homogenized in .5 mL lysing buffer with the Powergen 125 while kept on ice. Two µl of protease inhibitor was immediately added to the homogenate which was then sonicated, treated with very small portions of DNAse and RNAse, incubated at 37°C for 30 minutes and allowed to sit at room temperature for another 30 minutes. The samples were centrifuged at maximum speed for ten minutes, and the supernatant was collected. A 2D quant kit was used to determine the protein concentration of the supernatant. Rehydration with Bio-Rad 3-10 non linear strips and 185 µl of each sample was done following the Bio-Rad protocol. Isoelectric focusing was carried out to 18545 voltage hours using the Bio-Rad protean IEF machine. The samples were each run on a polyacrylamide gel for 65 minutes, stained, and observed using the PDQuest software. This study is currently being modified to obtain clearer, more concise results.
Functional Decline in Elders: What are the Associated Risks?
Joshua S. Mallett1, Huiping Xu2, Professor Laura P. Sands3, Professor Bruce A. Craig2 1Northern Arizona University, 2Dept. of Statistics, Purdue University, 3School of Nursing, Purdue University
Elders' declining ability to function independently from day to day has been associated with decreased quality of life, increased caregiver burden, and nursing home placement. In this study, we investigate progressive loss of basic activities of daily living (ADL) functioning in a cohort of community-living older adults. The ADLs we studied are bathing, toileting, and transferring from a bed. The database used (PACE) contains observations conducted every three months. We sought to determine how elders' dependence changes over quarterly intervals. Dependence is defined as needing the help of another person or assistive devices to perform an ADL task. A focus of these analyses was to determine rates and risks for transitions that marked a decline in functioning, including death. Potential risk factors associated with functional decline and death include the demographic variables age sex, ethnicity, and living status as well as the baseline health status variable prior hospitalization. Contingency tables were created to observe the transitions in functioning in each of the three activities of daily living from baseline to quarter one and quarter one to quarter four. We then created several tables to observe progressive loss in functioning in these ADLs with attention to identifying potential demographic and health status risks. Chi-square and Fisher's exact tests were then run to test for significance. Sex, ethnicity, living situation, and prior hospitalization showed association with transition in level of dependence for some of these ADLs such as bathing, toileting, and transferring in association with ethnicity and living situation but not for transferring in association with sex. Age showed significance in all transitions. Incrementally greater percentages of death were observed with greater levels of disability for each of the three ADLs from quarter one to quarter four especially. To predict probability of death, logistic regression analyses were run. We created two models to predict the log(odds of death) at quarter one and log(odds of death) at quarter four. The first model (transition from baseline to quarter one) revealed that age, ethnicity, living situation, and level of dependence in toileting were significant predictors of change. Age, living home with someone, dependence in toileting, and being Asian and Black were positive. Living in a group home, having some help in toileting, and being Hispanic were negative. Age (OR 1.023), living home with someone (1.244), and increased dependence in toileting (OR 1.552, 3.029) were associated with an increased risk of death in this model. The second model (transition from quarter one to quarter four) identified age, sex, ethnicity, living situation, an interaction between age and sex, level of dependence in bathing and transferring, and use of an assistive device in toileting as significant predictors of change. Age, living home with someone, dependence in bathing and transferring, using an assistive device in toileting, and the interaction of age and being male were positive. Being male, Black, Hispanic, living in a group home, and having some help in bathing and transferring were negative. Living home with someone (OR 1.019), increased dependence in bathing (OR 1.507, 2.391), increased dependence in transferring (OR 1.318, 1.954), and use of an assistive device for toileting (OR 1.29) were associated with an increased risk of death in this model. These models displayed differences due to ethnicity and sex.
Andrew Marky, College Misericordia and Professor Angus Murphy, Department of Horticulture
In order to analyze the function of a gene it is crucial to determine where it is expressed and localized in the cell. Promoter and gene fusions to various reporter lines are widely used for such expression and localization studies. The fusion proteins can be used to transform plants and generate stable transgenic lines or they can be used for transient assays. We have been making reporter constructs, fusing the Arabidopsis Aminopeptidase gene, APM1, to RFP, YFP and HA tags. We are using p35S and pGreen vectors for our study because pGreen is a binary vector that is used to transform plants which will yield stable transgenic lines. These reporter fusions will be transiently expressed in onion epidermal cells by particle bombardment and the localization of the protein will be studied. We shall also be analyzing the expression patterns of the gene using Promoter – GFP fusion lines. Finally, we will be screening promoter GUS fusion lines and selecting plants resistant to kanamycin. Cloning with both p35s and pGreen vectors is used as a means of fusing the APM1 gene to there respective reporters. The 35s is inserted by using EcoR1 which is an enzyme that recognized a site to cut. In analyzing the APM1 gene, we look to determine its function. The importance of knowing the function of this gene is that it can be used in other studies because it mammalian homolog is directly linked to diabetes. By exposing these plants to different environmental factors, the response of the GUS and GFP lines will be analyzed. In order to replicate our DNA we use a PCR (polymerase chain reaction) machine. The machine heats up to a certain temperature, that enables the DNA to unravel. At this point, the machine will cool down, and a primer will attach to each strand and a taq. will add Nucleotides to this template strand. This process will repeat for about three hours and the results will be millions of copies of DNA.
Characterization of BIK1-dependent genes for resistance to biotrophic and necrotrophic pathogens in Arabidopsis thaliana
James Morgan, Fort Valley State University and Professor Tesfaye Mengiste, Department of Botany and Plant Pathology
Necrotrophic pathogens cause widespread and destructive diseases by inducing cell death in their plant hosts. Our long term goal is to understand the cellular and molecular mechanisms that regulate host responses to microbial necrotrophy. During an investigation of host responses to necrotrophic pathogens, the Botrytis-induced kinsase (BIK1) gene was identified as a crucial component of host resistance to pathogen infection. Inactivation of BIK1 in Arabidopsis caused increased susceptibility to two necrotrophic fungal pathogens, Botrytis cinerea and Alternaria brassicicola, but increased resistance to the virulent pathogen Pseudomonas syringae, suggesting that BIK1 plays distinct roles in controlling resistance to biotrophic and necrotrophic pathogens. Pathogen induced gene _expression between mutant and wild type plants infected with Botrytis identified BIK1 dependent genes. Mutant plants with a T-DNA insertion in BDGs were obtained from the Arabidopsis stock center and true-to-type, or homozygous mutants, were identified through PCR approaches. These BDG mutants will then be challenged with various biotrophic and necrotrophic plant pathogens to determine the function of these BIK1 dependent genes in disease resistance ! and their relationship to BIK1.
Nneka Nolisa, Pharm. D. Candidate, Xavier University of Louisiana College of Pharmacy and Professor Gail Newton, Department of Pharmacy
Purpose of this project was to assess the needs of Medicare beneficiaries and eligible senior citizens, focusing on their understanding of the Medicare reform program. Armed with this information brochures and education seminars would be developed providing pertinent information. Rationale: Starting in January of 2006, modifications to the Medicare program will be put in place. Most eligible seniors and beneficiaries are unaware of these changes; therefore arming them with this information should alleviate problems associated with choices about their health care coverage. Methods used for this project included: 1. Literature searches, 2. Development of survey for patient needs assessment 3. Administration of survey to current Medicare beneficiaries and eligible senior citizens. 4. Analysis of survey results 5. Development of educational material/seminars. Results: • 18 of 19 patients surveyed were eligible and on Medicare. • 10 out of 19 were high school graduates, 4 out of 19 did not complete their high school education, and 4 out of 19 had some college education, 1 out 19 had a high school degree. • Patients were on a number of medications ranging from none to 13 medications per day. With an average of about 5 medications, and 4 out of 19 patients were on more than 10 medications daily. • Only 6 out of 19 patients reported their annual income which ranged from $8,500-$17,600. • 6 out of 13 patients who reported their monthly medication expenses will benefit from this new drug program if they qualify, because their expenses are $800 or more annually. • The most common answer to the question “What questions do you have about any aspect of Medicare” was “Many”. Status of project: Currently, education materials are in the development process. Talks/seminars geared towards Medicare beneficiaries have been scheduled and will occur in the near future. Tentative conclusion: Our study supports the assumptions that most Medicare beneficiaries do not understand the program and are unaware of up coming changes. This project has also made us aware of the fact that with the new changes occurring with Medicare, Pharmacists will be a major source of information for patients. However, most pharmacists are not privy to these changes either. Therefore, education pieces can and should also be developed for Pharmacists. Due to the small sample size utilized in this study, continued work is needed on this project. Conclusive results cannot be obtained from this small study however, can be used as a focus group. It can serve as the basis for future studies.
Laser Instrumentation for Experiments in Atom Optics
Stephen Pace, Prairie View A&M University and Professor Daniel Elliott, School of Electrical and Computer Engineering
In this program we will use multi-frequency standing wave laser fields to focus beams of neutral atoms onto a silicon substrate. This process is called neutral atom lithography and may potentially be used to create the nanoscale integrated circuits of the future. We are building instrumentation to stabilize the laser frequency, necessary for focusing a neutral atomic beam onto a substrate or wafer. Our process will use electrical feedback generated from an absorption line in atomic Rubidium to “lock” the laser frequency, using synchronous detection. A 100 kHz oscillator will be used to modulate the absorption line (through the Zeeman Effect), and we will detect the frequency error using a lock-in amplifier. This error signal will be applied to the laser to complete the feedback circuit and we expect to control the laser frequency to within ±500 kHz using this technique.
Zeros of Complex Polynomials and Applications to Force Fields
Vertonica Powell, Fayetteville State University and Dr. Johnny E. Brown, Professor Department of Mathematics
Given a polynomial p(z) of degree n with complex zeros at zk, the zeros zk can be interpreted physically as the point sources in an electric force field with positive integer charges located at the zk. Conversely, given an electric force field with positive integer charges at zk, there exists a corresponding polynomial p(z). The force exerted on a test charge is inversely proportional to the distance from the point source. The equilibrium points in this force field correspond to the zeros of p'(z), the derivative of p(z). Knowing the location of equilibrium points in this force field is important and useful. If all the point sources are located inside the unit disk, it has been conjectured that there must always be an equilibrium point within unit distance of the point source i.e., each zero of p(z) must have a critical point within unit distance of it. This conjecture, the Sendov Conjecture, was posed in 1962 and has only been verified in a few cases and for polynomials of degree n = 8. It is known that if 0 is a zero of p(z), then there must be a critical point within unit distance of 0. We generalize this result. In our special cases we want to study the behavior if a zero zk is close to 0. More precisely if z0 is a zero of p(z) such that |z0| = dn (hence is sufficiently close to 0) and all the critical points are real, then there is a critical point within unit distance of z0. We obtain the best estimates for dn for such polynomials for n = 9. For example, Phelps & Rodriquez give the estimate d9 = 0.4060 and Brown gives d9 = 0.4913 while our new estimate gives d9 = 0.5282. Estimates for n > 9 are also obtained and are best for this special class of polynomials (PR).
Interference and Cueing Effects in Conscious Awareness
Tessie Puentes, California State University-Lon Beach, Professor Ian Neath and Professor Aimée Surprenant, Department of Psychological Sciences
Activation theories of immediate memory, such as the Embedded Processes View, posit that items in the focus of attention do not need to be retrieved and are not vulnerable to interference effects. In contrast, alternative views argue that all types of memory follow the same rules; therefore all forms of memory should be vulnerable to interference. An n-back task was adapted to see if interference could be observed for items in the focus of attention. Twenty participants saw a list of letters presented one at a time. At test, participants were asked to determine whether the probe letter was the same letter that appeared 1 back from the end of the list. On trials in which the probe item was the item 1back, the presence of an additional similar-sounding letter was expected to increase accuracy and decrease response times (cueing). On trials in which the probe item was not the item 1 back, the presence of an additional similar-sounding letter was expected to decrease accuracy and increase response time (interference). Contrary to the Embedded Processes View, evidence of both interference and cueing were found in the accuracy data after just 1 session and also after 4 sessions. Results yield support for views that argue that memory principles are the same regardless of the type of memory system.
Acquisition, Analysis, Archiving and Dissemination of Real-Time and Archival Satellite Data from Multiple Sensors
Cliff Robinson III / Purdue University, Texas Southern University, Larry Biehl and Professor Gilbert Rochon, Department of IT Discovery Resources
The field of this title deals with taking remotely sensed information and using it for a variety of purposes which include sharing information and analyzing information. There are several aspects where remote sensing can be useful in a beneficial fashion, such as the monitoring and planning for the recent hurricane (Dennis) as well as other natural disasters. Other uses include national security issues as well as economic issues. With my research, I learned the proper procedure to obtain information directly from one or multiple satellites feeds, then was able to use specialized software to analysis this data and to mold it into a product that can be viewed and understood by people who may or may not be in the same field as I. Another important aspect of what was worked with was the ability to distribute and share this data to other universities and facilities which may not have their own remote sensing ground station or Terrestrial Observatories. My efforts were in affiliation with the laboratory for remote sensing at Purdue (LARS) as well as the Purdue Terrestrial Observatory (PTO). My mentors Larry Biehl and Gilbert Rochon were vital in my learning of this trade. • Acquisition - the process of locking tracking equipment on a signal from a communications satellite. • Analysis - The process of systematically applying statistical and/or logical techniques to describe and illustrate, condense and recap, and evaluate data • Archiving - storing copies of important files, datasets, and or images for reference purposes. • Dissemination - The transfer from the stored form of a digital object in a repository to a client. Making information publicly available. • Process – Digitally received data is embedded in a RF carrier wave and a pulse is added to the signal; this is transmitted to the earth. – An antenna dish captures the signal and reflects it to the feed in the focal of the dish. – RF electronics concentrate, amplifies and changes the signal to enable it to pass through a coax cable to the receiver. – The receiver separates (demodulates) the received digital data from the carrier and passes it though a bit synchronizer before sending the data to the frame synchronizer. – The frame synchronizer separates the data into frames and the data is sent to be stored and processed as TDF files. • Components – LARS (Laboratory for the application of Remote Sensing) – PTO (Purdue Terrestrial Observatory) – Multispec – IndianaView • A sophisticated real-time remote sensing ground station array, capable of receiving satellite data from multiple panchromatic, multi/hyperspectral and radar sensors, at a wide range of spatial resolutions. – Created in 3 phases – Center for Geo informatics Research • Uses – Homeland Security: food security, epidemics, epizootics, power grid integrity, nuclear power plants integrity – Environmental and Ecological: watershed-scale hydrological monitoring, methodology for sustainable natural resource management, urban development/sprawl. – Meteorology & Climatology: storm system characterization and tracking, Climate change vulnerability assessment – Economic Development: strategic business site location, 3D geological visualization & mineralogical exploration analysis, environmental impact assessment & thermal energy conservation analysis
Effects of Deletions into YFV NS1 and NS2A on Replication
Cinthia E. Sánchez Hernández,1, Dr. Muriel Soler2 and Professor Richard J. Kuhn2 1Natural Sciences Department, University of Puerto Rico-Aguadilla 2Department of Biological Sciences, Purdue University. Purdue Cancer Center NCI CURE Program
The Yellow Fever Virus (YFV) belongs to the genus Flavivirus within the family Flaviviridae. The YFV is an arbovirus transmitted from person to person by Aedes aegypti mosquito and continues to be a global problem that causes human mortality. The YFV genome is a positive- sense RNA approximately 11 kb in length that is capped at the 5' end but lacks a 3' poly (A) tract. The virus genome encodes a single large polyprotein that is arranged with the structural proteins at the amino terminus (C-prM-E), followed by the nonstructural (NS) proteins (NS1 through NS5A). Among YFV non-structural proteins, NS1 seems to be required for early RNA replication and function as a component of the replication complex. NS2A has been implicated in infectious particle assembly and to also be a component of the replication complex. No structural data is available for NS1 and NS2A, so far. A previous study, done in Dr. Richard Kuhn's lab, allowed us to sketch out a first draft of NS1 and NS2A maps highlighting possible functional properties of different regions of these two proteins. In that study, a random transposon mutagenesis system was used to generate clones containing 19 amino acid insertions in the NS1 and NS2A regions. Based on these data, the aim of this research project is to design and produce some clones containing specific deletions in the NS1 and NS2A regions of a YFV replicon containing a Renilla Luciferase reporter gene. The use of this replicon is a vehicle for the analysis of genome replication. As a starting point, we initiated some specific deletions in the NS1 and NS2A regions of the YFV replicon. Although this experiment is still in the preliminary stage, a total of 10 mutations have been generated so far. Further, the mutants will be characterized with respect to replication and trans-complementation, BHK cells (baby Hamster Kidney) will be electroporated with the YFV replicon containing the Renilla Luciferase reporter gene and also containing the specific deletions in the NS1 or NS2A regions. The activity level of the Luciferase will indicate the level of replication and tran-complemetation.
Potential Individual versus Simultaneous Climate Change Effects on Maize Crops (C4): Model Based Study
Sherry R. Smith1, Dev Niyogi2, and Sudeshna Paul3 1College of Agriculture & Human Sciences, Prairie View A&M University, Prairie View, TX 2Departments of Agronomy and Earth & Atmospheric Sciences, Purdue University, West Lafayette, IN; Indiana State Climate Office 3Department of Earth & Atmospheric Sciences, Purdue University, West Lafayette, IN; Indiana State Climate Office
Agriculture can potentially be affected by changes in regional weather and climate, which effects crop productivity. Responses to climate change can be detected by changes in temperature (T), radiation (R) and precipitation (P). This study seeks to address the question: what is the effect of individual versus simultaneous changes in T, R, and P on plant response such as crop yields in a C4 plant? This question is being addressed by conducting a modeling experiment for maize (C4) crops using the Hybrid – Maize model. The model was configured over a weather experiment station in Ames, IA [93.75N, 42.02W]. Observed weather and field conditions corresponding to 2003 were used as the control. Hybrid – Maize responses to individual changes in R and P (25% and 50%) and T (±5°C) were studied. Results from the experiment indicate: (i) changes in radiation are the most sensitive and directly affect yields and water loss due to ET; (ii) temperature is not as prominent as R; and (iii) precipitation has a very limited impact. Analyzing the simultaneous change results do not agree with those from individual changes, particularly T. The analysis indicates for changing precipitation (rainfall), temperature and radiation feedbacks show a non – linear response on yield. The study results indicate that temperature – radiation related changes resulted in significant changes to C4 crops. In the future, climate change impact studies should consider other variables that will help identify plant vulnerability and feedback in estimating major impacts.
Financial and Investment Strategy for Tomato Growers in California
Courtney Stewart1, Professor Allen Gray2, Ms. Maude Roucan2 1College of Agriculture and Human Sciences, Prairie View Agricultural and Mechanical University, 2Department of Agricultural Economics, Purdue University
The study describes the growth phases and opportunities of a tomato grower's farm. In many cases, farmers faced with several avenues of growth and development. Most of these can be broken down into two basic classifications; horizontal and vertical. The characteristics of the model farm are based on the participants' farms and literature. The farm is located in California with a total acreage of 4,200 acres. Of these 4,200 acres, 1,200 will be used for growing processing tomatoes, and the rest will be for alfalfa, cotton, dry beans, wheat, and onions. The farm is faced with two growth opportunities. The first opportunity is in terms of horizontal growth, meaning buying more land and growing more tomatoes, or other cash crops, such as almonds. The vertical opportunity is to invest in a transplant house. Before making a decision as to what the farm should do, they must answer these questions: “How much would it cost to buy the land, and grow the crop?”, “How much would it cost to build, equip, and run the greenhouses?”, and “How much are we worth right now?” The project consists of doing background research for a case study that attempts to address these questions for an upcoming educational program for tomato growers. This case study will be used to teach economic strategy and finance. My research includes finding information on both facets of growth. My research has been focused mainly on vertical growth. Based on the feedback received and literature, I have been creating several spreadsheets that measure the financial background of the farm revenues, cost of investment, and profit. I have also been in communication with professionals in the field of the greenhouse industry, professors, and bankers. The case study will present information based on several different studies, interviews with professionals, and financial documents. Based upon the financial documents prepared (production costs, income statement, and balance sheet), the farm will make a wise decision as to which route is best, and if it is feasible. This assessment of funds and investment ability is known as the concept of Net Present Value. For example, we sill see if the farm will save money by growing its own transplants, rather than purchasing them from a transplant house. If the profit margin is large enough, then the farm will consider growing transplants for surrounding farms, investing with other farmers in a transplant house, or privately owning and operating
Molecular and phenotypical analysis of immunophilin genes in Arabidopsis
Torres, Mirayda* - Schulz, Burkhard† - Krasnyanskaya, Viktoria† *University of Puerto Rico-Mayagüez Campus – Purdue University
Immunophilins are characterized by their ability to bind immunosuppressive drugs such as CyclosporinA (cyclophilins) or FK506/Rapamycin (FK506 binding proteins = FKBPs). Binding of the drugs leads to inactivation of the immune system in animals and humans. Plants, as well as microorganisms and fungi, also possess immunophilin genes. In Arabidopsis, 23 different FKBPs are known. They localize to nucleus, cytoplasma and chloroplasts. As most FKBPs have chaperone activity, they might be involved in protecting plant proteins towards different cellular stress . The expression of many FKBPs is up-regulated under stress conditions , , . The well characterized Arabidopsis FKBPs TWD1, ROF1 and ROF2 were selected in order to investigate the mutation effects in these genes during stress responses in plants. Null mutations of the FKBP-like immunophillin TWISTED DWARF (twd1) cause severe dwarfism and disorientated growth of all organs: Stem and siliques show the typical twisted growth of twd1. Null mutations of the ROF1 and ROF2 show no visible phenotype. To test the response of mutants toward stresses, surface-sterilized seeds were germinated on agar plates with 0.5 x MS medium for 5 days at 22°C and in the presence of light. Seedlights were then transferred onto agar plates with 0.5 x MS medium and supplemented with either NaCl, mannitol or ABA and incubated under constant light for 7 days. The increase in length was then calculated from the recorded growth per day of each plant. The plants were grown on soil for 3 weeks at 24°C, 16hrs light period and constant watering. Drought stress was induced by withholding water for 9 days. The response of mutants and wild-type plants toward different stresses shows, for most treatments, no significant changes. However, a striking difference could be found for FKBP double mutants of ROF1 and ROF2 in salt sensitivity tests. Plants containing mutations for both genes show a hypersensitive phenotype on 150 mM NaCl. Seedlings were bleached out after a few days and the root growth was stopped, whereas single mutants and wt-plants still showed partial resistance on 150 mM NaCl. The drought experiments show that the mutants twd1-1, twd-sup and the double mutant pgp1/pgp19 are more resistant to drought than wild type plants. Rewatering of plants after drought period results in recovering in twd1 and ABC transporter mutants, but not in wt-plants.
Expression And Characterization Of Metallothionein-Like Proteins From Arabidopsis Thaliana.
Juliana Zuniga1,2, Charise Lloren1,2, Matheus Benatti2, Michael Persans2, Peter Goldsbrough2, Angus Murphy2 1Department of Horticulture- Purdue University, La Fayette, IN 2Department of Biology- University of Texas-Pan American, Edinburg, TX
In animals and yeast, metallothioneins function in metal ion homeostasis. In plants, metallothionein-like proteins have been implicated in metal responses, but their metal binding characteristics are unknown. Arabodopsis Thaliana has been found to have 7 actively expresses MT genes. MT1a, MT1c, MT2a, MT2b, MT3, MT4a and MT4b have been grouped according to their amino acid sequence and gene structure. In this experiment, emphasis has been placed on AtMT1a, 2a, and 3 and their role. These have been cloned into pMAL-p2X expression vector. The MBP-AtMT fusion proteins have been heterologously expressed and purified through affinity chromatography. The purified recombinant protein will be used to conduct assays in metal binding activity and antioxidant activity. Furthermore, as native Arabidopsis proteins are sometimes associated with membrane fractions, the expressed proteins will also be analyzed to determine if they can be prenylat! ed in an in vitro system.
