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Collegiate Division 2000.

Biology Section

Bambard, N.D. and D.R. Lee. Department of Molecular Microbiology and Immunology, University of Missouri-Columbia. BINDING OF HIV PEPTIDE EPITOPES TO HUMAN HLA-B7 SUPERTYPE MHC CLASS I ALLELES. Previous studies in this laboratory have refined a protocol for performing peptide binding assays on lymphoblastoid cell lines [LCLs] (EBV-transformed B-cell lines). This study is being performed (using this forestated protocol) to analyze the ability of HLA-B7 supertype MHC class I alleles to bind specific HIV peptides. Preliminary studies indicate that each of three distinct HLA-B7 restricted HIV peptides (HIV env 303-312 HXB2 {365}, HIV nef 68-76 LA-I {366} and HIV nef SF-2 {367}) exhibit binding characteristics that are significantly above the negative baseline controls (cells exposed to no peptide, and cells exposed to an irrelevant (HLA-B7-restricted) peptide (FLU NP 380-388) {244}). Subsequent experimentation will attempt to discern the quantity of each peptide that is required to induce half-maximal binding. Mor e importantly, the ability of the three B7-restricted peptides to bind to other B7 supertype alleles will be tested. Additionally, other HIV peptides that bind to another HLA-B7 supertype allele will be tested for their ability to bind to the other supertype alleles. These studies will potentially provide HIV peptides capable of binding to multiple HLA-B7 supertype alleles and inducing immune responses against HIV in a greater proportion of the human population. Supported by the Life Sciences Undergraduate Research Opportunities Program (LS UROP), University of Missouri-Columbia; MU Research Board (URB-99- 127 Lee); DHHS 1R21AI45469.

Borrok, M.J. and O.B. Mock. Kirksville College of Osteopathic Medicine. AGING STUDIES IN MALE LEAST SHREWS (Cryptotis parva). Known-aged least shrews were placed in five age-based groups. Each group contained at least five males whose ages were within a 190-d time span. Analysis of testis color, sperm counts and organ measurements compared actual age for regression analysis (RA) and group data for analysis of variance (AOV). Values for 50- and l000-d old males are listed for parameters that showed significance with RA as follows: absolute and relative spleen weight, 0.013mg, 0.25% and 0.024mg, 0.43% respectively; lower incisor length, 32mm and 23mm respectively: and crystalline lens 2.9mm and 2.1mm respectively. Data plots for absolute liver, kidney and testis weights, ampullary gland and bulbourethral gland greatest diameter, and total sperm counts were nonlinear with middie aged males showing significantly higher values than the younger animals as determined by AOV. Testis color was light gray for all males up to 72-d old and very dark gray for all males over 220-d old (as compared to Munsell Color Charts). Lower incisor length, spleen size, and testis color are the parameters that best estimate least shrew's age. Decreased lens diameter resulted from the progression of cataracts in most shrews over 370-d old. Supported by EPA grant. CR823734010 and PRIMO grant ER0186-8024-001.

Brooks, T.T., L.R. Ayyagari. Department of Biology, Lindenwood University. DEVELOPMENT OF AN ASSAY FOR THE MEASUREMENT OF D-GLYCERALDEHYDE PHOSPHATE DEHYDROGENASE IN LEG MUSCLES OF THE WOLF SPIDER. We optimized the assay conditions for the measurement of D-glyceraldehyde phosphate dehydrogenase. In this assay, we were able to measure enzyme activity in the range of 1.25 units to 6.25 units. A 0.33-millimolar triethanol amine buffer system was used at a pH of 7.8 with all of the reagents of the assay system at 3.0-millimolar concentrations. A decrease in the absorbance of reduced NAD was measured at 340 nm as an indicator of the enzyme activity. After standardization of the assay, we applied it to determine D-glyceraldehyde phosphate dehydrogenase in resting leg muscle homogenates obtained from wolf spiders. The enzyme activity ranged from 0.125 units to 2.0 units (n=3) for female spiders and 1.5 units to 2.0 units (n=2) for male spiders. Future studies will concentrate on the effect of short spurts of exercis e on this glycolytic enzyme in wolf spiders.

Broz, A.K., B.P. Mooney, J.A. Miemyk, and D.D. Randall. Department of Biochemistry, University of Missouri. MITOCHONDRIAL PYRUVATE DEHYDROGENASE COMPLEX: INVESTIGATION OF THE UNIQUE DIHYDROLIPOAMIDE ACETYLTRANSFERASE SUB COMPLEX FROM PLANTS. Two isoforms of the acetyltransferase (E2) component from the pyruvate dehydrogenase complex have been identified. One isoform contains a single lipoyl domain and is believed to be ubiquitous, while the other consists of two lipoyl domains and has only been identified in dicots. Previous experiments have led to the cloning and expression of the dilipoyl E2 isoform from Arabidopsis thaliana, however, both isoforms are needed to perform comparative studies. Recently, an A. thaliana gene encoding the mono-lipoyl E2 isoform was discovered through a genome project. This gene was identified by alignment with the maize E2 protein sequence (also mono-lipoyl). This information was used to clone a cDNA encoding an A. thaliana protein. The isoform was cloned using PCR, and subjected to restriction enzyme analysis. The protein is presently being expressed in bacteria. The recombinant protein will ultimately be used in comparative studies with the previously isolated A. thaliana di-lipoyl E2. An investigation of the two E2 isoforms in A. thaliana and other dicotyledon plants will yield information about their regulation and function. Future experiments will be conducted to determine the catalytic differences between the two isoforms and their interactions in vitro. This will yield important information to help in understanding the assembly and function of the pymvate dehydrogenase complex. Supported by the Life Sciences Undergraduate Research Opportunities Program, University of Missouri, Columbia.

Burks, F., E. Sugano, and A.D. McClellan. Department of Biological Sciences, University of Missouri-Columbia. MECHANISMS FOR INCOMPLETE REGENERATION IN SPINAL CORD-TRANSECTED LAMPREY. Severe spinal cord injury in higher vertebrates, such as birds and mammals, results in permanent paralysis below the lesion because of an inability of axons of descending brain neurons to regenerate. In some lower vertebrates, such as lamprey, neurons can regenerate their axons across a spinal cord injury site and restore motor function, including locomotion. However, in lamprey the brain neurons that regenerate their axons across the injury site appear to project for shorter distances and are fewer in number than in normal animals. Thus, regeneration of axons across the lesion is incomplete. Because of this incomplete regeneration, we hypothesized that the degree to which a descending brain neuron is stimulated to regenerate is based, in part, on the number of synaptic connections it makes, both above and below a lesion. In the present study, lamprey were divided into two groups, one in which the spinal cord was transected rostrally at 10% body length (BL) and another group in which the spinal cord was transected caudally at 50% BL. After 4, 6, 8, 16 and 32 week recovery periods, a retrograde anatomical tracer, horseradicsh peroxidase (HRP), was placed just below the transection site (20% BL and 60% BL) to label descending brain neurons that regenerated their axons across the lesion. Subsequently, the brains and spinal cords were removed and processed for HRP and the numbers of labeled descending brain neurons were counted. Because the spinal lesion at 10% BL eliminated most of the spinal targets of descending brain neurons, these neurons were strongly stimulated to regenerate their axons. Thus, greater numbers of these neurons were labeled compared to the animals with a spinal transection at 50% BL.

Deschenes, B., C. Snook, P. Tipton, L. Beamer. University of Missouri-Columbia. CRYSTALLIZATION OF AN ENZYME INVOLVED IN SECONDARY INFECTIONS OF CYSTIC FIBROSIS PATIENTS. The Gram-negative bacteria Pseudomonas aeruginosa secretes alginate, which forms a viscous coat around the organism. Alginate is a beta- 1,4-linked polymer of mannuronic acid and its C5 epimer, guluronic acid. P. aeruginosa infections are common in immune compromised patients, specifically those suffering from bums, wounds, and cystic fibrosis. The alginate seems to benefit the bacteria in more than one way. The alginate protects the infecting bacteria from dehydration in the lung environment. The coating protects the infecting cells from antibiotic treatment and phagocytosis by the host immune response. Alginate also appears to help the bacteria attach to the hosts' lung epithelial cells. Tuming off the alginate biosynthetic pathway would enable the use of traditional antibiotics to treat these infections. The pathway for alginate synthesis is well defined; however, the enzymes involved have not been studied in detail. Our lab has crystallized the enzyme GDP-mannose dehydrogenase (GMD), which converts GDP-mannose to GDP-mannuronate in the committed step of the alginate biosynthetic pathway. GMD is a 48 kDa protein that is believed to form a 290 kDa hexamer in solution. The enzyme appears to have two domains. The amino-terminal end has an NAD and GDP-D-man-nose binding sites. To gain more knowledge about how GMD works, a 3-D structure of the enzyme is needed. We have successfully grown crystals of native GMD and obtained a native data set to 2.4 A resolution at [sim]180[degrees] C. Preparation and crystallization of selenomethionine GMD is in progress in order to solve the crystal structure by multiwavelength anomalous diffraction. This research is supported by the Life Sciences Undergraduate Research Opportunities Program, University of Missouri-Columbia.

Dunham, C. Department of Biology, Culver-Stockton College. ALLELOPATHIC EFFECTS OF Phalaris arundinacea EXTRACTS ON Avena sativa GERMINATION AND SEEDLING GROWTH RATES. The purpose of this research was to test the hypothesis that Reed Canarygrass (Phalaris arundinacea) exhibits allelopathic tendencies upon neighboring plants. Reed Canarygrass, is a perennial, winter hardy, drought and flood tolerant cool season grass. Invasion of this species has become a major concern from the wetlands of Minnesota through southern Missouri. Allelopathic effects of Phalaris arundinacea on Avena sativa germination and seedling growth were studied using extracts made from an emulsion of green and dead Phalaris arundinacea above ground growth and subsequent application of this emulsion to Avena sativa plants. This research was conducted under greenhouse conditions with abundant light and constant temperature regulation. Results indicate that there is no significant effect upon Avena sativa germination and seedling growth rates ( p[greater than]0.05). This study parallels research conducted October-November 1999 using Raphanus sativus.

Ekong M., J.K. Eberhardt, M.E. Swartz, C.E. Krull. Division of Biological Sciences, University of Missouri-Columbia. USING IN OVO ELECTROPORATION TO EXPRESS GFP IN AVIAN EMBRYOS DURING AXON PATHFINDING. Previous studies have demonstrated that the EphA4 receptor tyrosine kinase and its two ligands, ephrin-A2 and ephrin-A5, are expressed in complicated patterns during axon outgrowth to the avian hindlimb. To decipher the function of these molecules in axon pathfinding, we are using in ovo electroporation to express dysfunctional forms of EpliA4 in motor neurons and their axons. As a first step, a DNA construct encoding Green Fluorescent Protein (GFP) was injected into the lumen of the neural tube and electroporated into embryos at two days of development (Stage 14). In ovo electroporation drives the GFP-encoding construct into neuroepithelial cells in only one half of the neural tube; the other half serves as an excellent control. To determine the spatiotemporal pattern of GFP expression, embryos at 48-123 hour s post-electroporation were viewed using GFP optics. At 48 hours, GFP was present in developing motor neuron cell bodies on one side of the neural tube. At later stages, GFP was present in all motor neurons and their axons on one side of the neural tube that have extended to the hiadlimb. These studies demonstrate that GFP can be localized to motor neurons and their axons, and that GFP can be visualized for at least five days after in ovo electroporation. These results form the basis for our current experiments in which we are expressing truncated forms of EphA4, and evaluating the subsequent effects of disrupted EphA4-ephrin interactions on axon pathfinding. Supported by the Life Science Undergraduate Research Opportunities Program, University of Missouri-Columbia.

Ganley, B., J. Rhansali, J.S. Daniels, and K.S. Gates. University of Missouri, Columbia. REDOX-ACTIVATED, HYPOXIA-SELECTIVE DNA CLEAVAGE BY QUINOXALINE 1,4-DI-N-OXIDES. Quinoxaline 1,4 dioxides are well known antibacterial and antifungal agents that may be potential protoypes for modem, clinically promising heterocyclic N-oxide antitumor agents. To better understand the biological activity of the quinoxaline 1,4-dioxides we investigated their ability to cleave DNA through a redox-activated pathway in a well-defined in vitro assay system. Enzymatic activation of quinoxaline 1,4-dioxide (QDNO) primarily yields the redox-inactive quinoxaline mono-N-oxide (QNO). Redox-activated DNA cleavage by QDNO that occurs with low sequence specificity, and is completely inhibited under aerobic conditions and by common radical scavengers. The need for redox activation of QDNO coupled with the inactivity of the metabolite, QNO, strongly support the hypothesis that DNA cleavage by QDNO proceeds through enzymatic conversion of t he compound to an activated, oxygen-sensitive radical intermediate. We have also extended our studies to a naturally occurring antibiotic 2-carboxyquinoxaline 1,4-dioxide. This natural product displays DNA-cleaving properties analogous to the parent compound, QDNO. Our work provides the first direct evidence that quinoxaline 1,4-dioxides are redox-activated DNA--cleaving agents, and may provide a chemical basis for understanding the biological activity of this class of antitumor, antibiotic, and antifungal agents. Supported in part by Monsanto Corporation and the Arnold and Mabel Beckmann foundation.

Gentry, B., N. Oehrle and D. Emerich. University of MIssouri-Columbia. Soybean, the number one cash crop in Missouri, forms a nitrogen fixing symbiosis with the bacteria, Bradyrhizobium japonicum. Previous experiments have failed to indicate that attachment of B. japonicum to soybean is mediated by a specific bacterial species-host plant interaction. Our laboratory discovered a rapid, multi-phasic attachment process that promises to resolve these previous ambiguous results. This assay suggests that there are four phases in attachment. Exposing plants to proteases before inoculation shows a significant reduction in the attachment of B. japonicum to soybean root hairs. This experiment shows that a protein found on the root hairs of the plant is involved in recognition, the first step of nodulation. Isolation of root hair proteins through sonication, precipitation, electrophoresis and Western blotting has been performed. Western blotting experiments have identified the putative receptor protein on soybean root h airs that mediates binding of B. japonicum.

Gerhardt, H.C. and G.M. Snyder. Division of Biological Sciences, University of Missouri-Columbia. INFLUENCE OF DURATION OF CALL ON PREFERENCE STRENGTH IN Hyla versicolor. Previous research has shown that when given the option between a mating call of short duration (in pulses per call) and one of longer duration, female Hyla versicolor show strong preference when the short-call alternative is well below average. A weaker preference occurs when the short-call alternative is near the average pulses per call. In that study one short-call alternative had 10 pulses per call (subaverage) and the other had 18 pulses per call (approximately average). The short-call alternative was tested against longer calls that differed by 10, 20, 30, and 50%. The specific aim of this study is to explore the effect on preference strength of using a short-call standard of intermediate duration (14 pulses per call). Females will be tested in an acoustic chamber and released directly between two speakers separated by 2 m. Each synthetic alternative will be played alternatively three times. The female will then be free to move. Female choice will be determined by movement in the directi on of either speaker (to within 50 cm of the speaker), as established in previous studies. These results will better quantify the overall preference function for call duration. Supported by the Life Science Undergraduate Research Opportunities Program, University of Missouri Columbia.

Huerta, J.A. and M.L. Spratt. Department of Biology, William Woods University. Ehrlichia SPECIES IDENTIFIED IN IXODID TICKS BY POLYMERASE CHAIN REACTION. We are assessing species of ticks from various MO counties for the presence of bacteria responsible for the ehrlichial diseases which are of increasing concern in both veterinary and human medicine. Vectors include Dermacentor variabilis, Amblyomma americanum and Ixodes scapularis, all Ixodid tick species found in Missouri, while the causative agents are small, obligate, intraleucocytic bacteria of genus Ehrlichia. At least nine Ehrlichia species have been identified, three of which have been found to cause human disease in the US: E. chaffeensis identified in 1986 as the cause of Human Monocytic Ehrlichiosis; the "HGE agent", cause of Human Granulocytic Ehrlichiosis identified in 1994; and in 1999, four MO ehrlichial cases were traced to E. ewingii. Fatality is estimated at 2-5% forE. chaffeensis and 7- 10% for HGE. Ticks have been collected from 30 MO counties, both by sweeping vegetation in state/national parks and through cooperating veterinarians. Records are kept of county of origin, species, sex of tic k, and host [where applicable]. DNA is extracted using a modified Marmur protocol. Using previously published primers, a nested PCR protocol first amplifies most of the 16s rDNA sub-unit; this DNA is then used for a second amplification using various species-specific primers. Samples are visualized by gel electrophoresis on a 1.2% agarose gel. Of approximately 210 individual ticks processed in 495 total PCR reactions, 5.8% test positive for E. chaffeensis, 4% for the HGE agent, and 1% for E. ewingii. Tick species testing positive include: 67% Amblyomma americanum, 22% Dermacento variabilis and 11% Ixodes scapularis. Data may be useful in protecting citizens against these potentially fatal emergent diseases.

LaBarge J.L. and Mailanick, M.A. Department of Physiology, University of Missouri-Columbia. EXTRACELLULAR PROBES OF THE NA/K ATPASE. Cardiac glycosides found in Foxglove extracts produce positive inotrophic effects in cardiac tissue by inhibiting the sodium/potassium pump (Na/KATPase). We are currently investigating several drugs' interactions with the extracellular loops of the Na/K ATPase through radioactive rubidium (a potassium surrogate) influxes. Dichioroterpyridine platinum(ll) (DCTP) (1 mM), a histidine modifier, did not inhibit Rb influx even though there is a highly conserved histidine in an extracellular half of a transmembrane domain. DCTP did inhibit Ca ATPase and acetylcholinesterase. Rats bind cardiac glycosides less well in part because of an arginine in the binding site. We hypothesize that modifying the arginine will increase ouabain binding to the rat red blood cell. PNitrophenyiglyoxylate (1 mM), an arginine modifier, did not inhibit the Rb influx in human RBCs. We can now test whether NPG modifies ouabain binding or pump activity in rat RBCs. Ultimately, the changes in ouabain binding to the Na/K ATPase after drug modification will help clarify the mechanism behind Na/KATPase resistance to cardiac glycosides in rats and perhaps in a subset of human non-responders. Supported by Life Sciences Undergraduate Research Opportunities Program, University of Missouri-Columbia.

Martin, R.I., and M.R. Enochs. Department of Sciences, Central Methodist College. THE EFFECT OF STRESS ON CALRETICULIN LEVELS IN RATS. Previous studies have shown that stress raises the incidence of flare-ups in patients with Lupus erythematosus. In addition, Lupus patients have elevated levels of Caireticulin (CRT). This study was designed to test whether stress is responsible for elevation of CRT levels in normal rats. Rats were divided into groups of six, one group remained unstressed and the other group was stressed at five minute intervals by swimming. CRT levels were measured by an ELISA, which was developed using rabbit anti-human CRT and anti-rabbit IgG, heavy and light chain (Goat) Perosidase Conjugate. Mean absorbance value at 450 nm at five minutes for the control rats was .7024 and for stressed rats was .7143. Mean absorbance value at 10 minutes for the control rats was .7021 and for the stressed rats was .7183. These differences were not significant. Future studies should examine effects of great er stress and look for binding of calreticulin to other serum proteins.

Maue, A.; B. Puttler; G.A. McDonald. Department of Medical Microbiology and Immunology, University of Missouri-Columbia & Department of Entomology, University of Missouri-Columbia. USE OF POLYMERASE CHAIN REACTION IN DETECTING Wolbachia postica. Wolbachia postica is an intracellular symbiont of many insects, including the alfalfa weevil (Hypera postica). W postica is present in some Western strains of this insect, while it is absent in Eastern strains. This is important because it has a correlation in Western strains with resistance to a natural predator, the wasp Bathyplectes curculionis. This study was conducted in order to produce a viable detection procedure to identity the presence or absence of W. postica in alfalfa weevils. Weevils were subjected to an extraction procedure that was developed by us. The resulting DNA containing supernatant was then further prepared through the Qiagen DNA purification system. The weevil samples were then individually subjected to the polymerase chain reaction (PCR). Five microliters (mL) of sample DNA, 8 mL of designed primers, and 37 mL of distilled water were used in conjunction with 50 mL of PCR Master Mix. These solutions were then put through 40 PCR cycles. After amplification, the DNA was precipitated in 300 mL ethanol and 10 mL sodium acetate. The samples were precipitated to form pellets, which then could be rehydrated with 35 mL of distilled water. Buffer was then added to the samples and the samples were subjected to agarose gel electrophoresis. Currently, we are testing Missouri alfalfa weevils using the Western strains as positive controls. Supported by the Life Sciences Undergraduate Research Opportunities Program. University of Missouri-Columbia.

Mayer, V., C. Brock and J. Woslery. Department of Biology, Rockhurst University. THE INTEGRATED DESIGN AND DEVELOPMENT OF INSECT FEEDING DETERRENTS. Bioassays of plant extracts and synthetic compounds have been conducted in the previous years to determine their potential as feeding deterrents for insects that normally feed on stored grain products or live plants. The current research is a cooperative effort between students in the departments of Chemistry and Biology. Bioassays were conducted using larvae of Tenebrio molitor in both choice tests and weight gain tests. The choice tests consisted of the meal worms (40 per group) being given a choice between treated and untreated bran meal. Measures of feeding preference were made. Feeding was also measured by initial mealworm average weight and mealworm average weight after feeding. Results suggest that alkynes by themselves and in combination with sublethal doses (lOOppm) of the commercially available insecticide sevin do show feeding deterrent activity. The m echanism appears to involve alkyne destruction of cytochrome P-450.

Montgomery, M. and M.D. Kirk. Division of Biological Sciences, University of Missouri-Columbia. DISSOCIATED ARTERIAL CELLS ISOLATED FROM Aplysia HAVE NEUROTROPHIC ACTIONS ON REGENERATING NEURONS IN CULTURE. Soluble and substrate factors influence axonal growth and synapse formation during development and regeneration. We have grown in culture cells dissociated from the anterior aorta of the sea slug Aplysia, and tested the influence of these dispersed arterial cells on neurite regeneration of co-cultured Aplysia neurons. A 2cm section of the anterior aorta was removed from 90-125gm Aplysia, digested in collagenase, rinsed, plated on poly-L-Lysine treated glass coverslips, and grown in Leibowitz L-15 medium supplemented with glutamine, salts and sugar (SL-15). In some cases arterial cells were plated on only one half of the coverslip. Neurons dissociated from the pleuralpedal ganglia of juvenile (10-20 gin) Aplysia were plated over the entire surface of the coverslips. Neurons grown in co-culture exhibited sig nificantly higher outgrowth compared to controls, and the effects were observed on both sides of coverslips that had arterial cells plated on only one half of the surface. These results suggest that the factor(s) that mediate the neurotrophic actions are soluble. Supported by NIH grant R01N530832, and an MU Research Council grant.

Palmer, I. V. Department of Biochemistry, University of Missouri-Columbia. MAMMALIAN ER-GAMMA. Estrogen plays a vital role in many physiological and pathological processes such as cardiovascular disease, breast cancer, prostate cancer, and reproductive physiology. Estrogen action is mediated by binding to estrogen receptors (ER). Genes for two estrogen receptors, ER and ER , have been identified in mammals. However, studies have indicated that cells remain partially responsive to estrogens in the absence of these two receptor forms, leading to the hypothesis that a third estrogen receptor is present in mammals. To test this hypothesis, we have designed a series of PCR primers based upon unique, conserved sequences in the ERs of various fish species. The ER found in fish is encoded by a sequence that is distinct from the mammalian ERs. Based on phylogeny, a homologue of the fish ER may be present in mammalian DNA. PCR using the fish-based oligo primers will be used to amplify mouse genomic DNA to search for ad ditional ERs. The PCR products of interest will be sequenced and compared to GenBank for known proteins encoding regions. A match between the newly sequenced mammalian ERs and the fish ERs would indicate the potential identification of a third mammalian ER. Identification of a third ER would have a major impact in the fields of cancer and reproductive research ranging from estrogen resistant tumors to developmental abnormalities. Supported by LSUROP, UMC.

Redwine, W.B., and G. Hagen. Department of Biochemistry, University of Missouri-Columbia. CLONING A HISTONE DEACETYLASE GENE FROM Arabidopsis thaliana FOR ANTIBODY WORK. Previously a member of our lab produced, and analyzed mutant Arabidopsis thaliana plants through mutagenesis experiments. One group of mutants has mutations within a histone deacetylase gene on chromosome 5. The purpose of this project is to clone a full length and a partial length copy of a histone deacetylase open reading frame. Both a full length and a partial, 3', 80 amino acid coding fragment were amplified with primers by way of PCR. The primers contained restriction sites that allowed the fragments to be incorporated into a protein expression vector. This vector allows high amounts of the protein to be synthesized in particular strains of Escherichia coli. Isolated protein can then be used to obtain antibodies to isolate proteins that interact with deacetylases, further elucidating pathways and mechanisms. Currently both a full length and a partial fragment have been isolated and cloned into the expression vector. We are currently sequencing the constructs before we isolate protein for antibodies.

Regni, C., P. Tipton and L. Beamer. Department of Biochemistry, University of Missouri-Columbia. STRUCTURE DETERMINATION OF AN ENZYME IN ALGINATE BIOSYNTHESIS Mucoid strains of the bacteria Pseudomonas aeruginosa secrete alginate, a linear polymer composed of b-D-mannuronate and a-L-guluronate residues. Alginate forms a viscous coating around the bacteria, and protects it from the host's immune response and antibiotic therapy. While the pathway for alginate biosynthesis has been defined, the enzymes involved have not been characterized in detail, and no detailed structural three-dimensional information is available. A key enzyme in the initial steps of the alginate pathway, phosphomannomutase/phosphoglucomutase (PMM/PGM) has been crystallized in our laboratory. PMM/PGM converts mannose 6-phosphate to mannose 1-phosphate and is encoded by the algC gene. PMM/PGM crystallizes in space group P212121 with unit cell constants of a=70.89, b=73.03, and c= 92.40 A. The structure of PMM/PGM was solved by MAD phasing to 2.2 A resolution. The model is currently being refined to 1.7 A. Details of the structure solution and an analysis of the active site will be presented. Supported by Life Sciences Undergraduate Research Opportunities Program.

Reynolds, A.M., K.M. Silkwood, M.R. Enochs and A. Spevak. Department of Science, Central Methodist College. PHYSIOLOGICAL RESPONSES TO OLFACTORY STIMULATION BY PHEREMONES. This study was designed to help determine if humans respond to pheromones as animals do. Pheromones are given off as an attractant to find a suitable mate. Estradiol or 5[alpha]-Androst-l6en3[alpha]-ol were dissolved in a 1 to 5 ratio of ethanol and water, then heated to make volatile. Eleven by percent or 5[alpha]-Androst-l6en3[alpha]-ol was used as the male pheromone, while the same concentration of Estradiol was used as the female pheromone. Ten males and eight females were used. All females were on oral contraceptives and were tested during the second week of the cycle. Using a physiograph pulse rate and galvanic skin resistance were measured. Temperature was also taken every minute. Subjects were exposed sequentially to the pheromone solution and the ethanol water control solution. Temperature and skin resistance, responses were inconc lusive. In 7 out of 10 males a small increase pulse rate occurred. None of the females responded to 5[alpha]-Androst-l6en3[alpha]-ol. These preliminary results suggest that estradiol may be a weak female pheromone.

Silkwood, K.M. and M.R. Enochs. Department of Sciences, Central Methodist College. ANTIBACTERIAL EFFECTS OF Achillea millefolium AGAINST Escherichia coli. Historically A. millefolium (yarrow) has been used to treat wounds of soldiers, specifically to coagulate blood. This study was designed to determine whether yarrow has antibacterial properties as well. Yarrow was prepared using both a 4.3% w/v boiling water extract (infusion) and a 4.3% w/v ethyl alcohol (200 proof) extract (tincture). The effects of the extracts on the bacterial growth were determined by a standard plate count. Doses of infusion or tincture ranged for 0ml to 2.5m1 per 5m1 incubation broth. There was no bacterial growth with any dose of tincture, including the zero control, indicating that alcohol was responsible for inhibition of growth. At the highest dose of infusion, growth was inhibited 20%. These results suggest potential use of yarrow as an antibacterial agent.

Subramanian, S. and T.E. Phillips. Department of Biological sciences, University of Missouri-Columbia. ROLE OF IL-8 IN INCREASED HT29-N2 CELL DIFFERENTIATION. The human colon adenocarcinoma HT29-18N2 cell line forms a monolayer of well-differentiated goblet cells when grown in a protein-free culture medium. Previous work had shown that cyclosporine increases the differentiation of these cells by an average of 94%. Cyclosporine also increases the autocrine secretion up to 0.36 ng/ml interleukin-8 (IL-8) from these cells. We hypothesized that cyclosporine increased HT29-18N2 cellular differentiation by inducing autocrine stimulation mediated by IL-8. To test this hypothesis, we examined the ability of exogenous IL-8 to modulate differentiation of HT29-18N2 cell line. Cells were grown on glass coverslips and fed every other day with 0, 0.3, 3.0, or 30 ng/ml IL-8 for 14 days. Following fixation and embedding in plastic resin, 0.9 um semi-thick cross-sections were prepared and stained with safranin O and Hematoxyl in. Computer assisted morphometric analysis was used to quantify intracellular mucin stores as a measure of differentiation. Cells treated with 3.0 and 30 ng/ml IL-8 showed a small (15-18%) increase in differentiation. This result suggested that the increase in differentiation evoked by cyclosporine might be partially mediated by autocrine secretion of IL-8. To further test our hypothesis, we looked at two other agents which are known to increase IL-8 secretion by our cell line, TNF a and IL-1. We found that neither of these drugs increased differentiation of HT29-18N2 cells. We conclude that cyclosporine induced differentiation of these cells is not mediated by IL-8.

Tesar D.B. and C.E. Krull. Department of Biological Sciences, University of Missouri-Columbia. SEGMENTAL ORGANIZATION OF AXON OUTGROWTH: ROLES FOR PNA-BINDLNG GLYCOPROTEINS AND EPHRIN-Bl. During neural development outgrowing spinal motor axons extend from the developing neural tube and into the adjacent mesodermal somites in a distinctive segmental pattern, entering freely into the rostral somite while being restricted from entering the caudal somite. This segmental arrangement of spinal nerves provides a relatively simple system in which to study the various positive and negative factors that influence axon pathfinding. Two particular glycoproteins that bind the plant lectin peanut agglutinin (PNA) are localized within the caudal somite and have been shown to induce the collapse of axonal growth cones in vitro. Here we demonstrate that blocking the function of these glycoproteins via the addition of PNA in avian trunk explants is sufficient to instigate defects in proper axon segmentation in approximately 60 % of treated cultures. These defects include decreases in axon fasciculation and invasion of some axons into the caudal somite, which they would normally avoid. Biochemical analysis via SDS-PAGE and Western blot shows that these two glycoproteins are distinct from ephrin-B1, a ligand for Eph RTKs that is involved in the segmental organization of neural crest migration. Furthermore we demonstrate that inhibiting the function of EphB RTKs via the addition of ephrin-B 1 --Fc fusion proteins plus PNA leads to no observable increase in the axon pathfinding defects compared to cultures treated with PNA alone. These results suggest that inhibitory signals from the caudal somite are mediated, at least in part, by two PNA-binding proteins localized within this region and do not involve signaling from EphB RTKs. Future experiments will investigate the potential functions of EphA RTK-ephrinA interactions and NCAM (neural cell adhesion molecule) in the proper formation precise structures within the vertebrate nervous sys tem.

Walker, A.W., A. Ealy and R.M. Roberts. Department of Animal Science, University of Missouri-Columbia. PRODUCTION OF RECOMBINANT INTERFERON-TAU IN MAMMAILIAN CELLS: THE EFFECT OF GLYCOSYLATION ON BIOLOGICAL ACTIVITY. Interferon-tnu (IFN-t) promotes the continuation of pregnancy in ruminants, such as cattle, sheep, goats and deer, by preventing the regression of the corpus luteum. Both glycosylated and unglycosylated forms of IFN-t are present and recombinant forms of nonglycosylated ovine and bovine IFN-t have potent biological activity. However, a recent study has shown that glycosylation of human IFN-t improved its antiviral activity. This study was undertaken to determine whether glycosylation affects the biological activity of IFN-t. Three cDNA were chosen for study. Two cDNA (ovine t6d, bovine tla) code for proteins with an N-glycosylation site at A5N78, while the third cDNA (ovine t4) lacks this site. Coding regions for all cDNA were cloned into pSecA mammalian expression vector (Invitrogen). Chinese ha mster ovary fibroblasts were transfected with plasmids and stablely transfected lines were selected based on their resistance to hygromycin. Proteins from all three IFN-t forms were detected in the culture medium by using western blotting with IFN-t-specific antiserum and by using antiviral assays. The molecular weight of ovine t4 was approximately 5 kDa less than that of ovine t6d and bovine tia. N-linked glycosylation was responsible for this increase in mass as treatment with PNGase F, an N-linked deglycosylating agent, reduced the size of ovine t6d and bovine tin to that of ovine t4. Efforts are now concentrating en purifying the IFN-t by affinity chromatography with an IFN-t antibody. After purification, antiviral assays will be used to determine whether glycosylation alters the bioactivity of these proteins. Supported by LS UROP, UMC.

White, T.A., J.C. Polacco and M.E. Hoyos. Department of Biochemistry, University of Missouri-Columbia. DETERMINATION OF ARGININE TRANSPORTER IN Escherichia coli. In germinating seedlings it has been proven that the amino acid, arginine, is broken down by an enzyme sequestered in the mitochondria, arginase. The focus of this study is by which mechanism this argiine is transported into the mitochondria for breakdown. To "see" this transporting mechanism, we will use E. coli. mutants that cannot transport arginine and characterize the altered gene. To find these mutants 1st) we will grow E. coli on a medium containing arginine as its sole nitrogen source for growth. 2nd) we will mutate these E. coli by transpositional mutagenesis. 3rd) we will select for the arginine transporter mutant by on canavanine (a toxic analog to arginine and, if utilized, will inhibit growth). The E. coli that grow on canavanine will be resistant. They will have a mutation in their argiine transporter, and should not be able to utilize arginine as its sole nitrogen source. Once the strain is confirmed, we can then introduce arginine transporter genes from plants. This should cause the transporting mechanism to, once again, become functional . Supported by the LSUROP, University of MissouriColumbia.

Woods, D., G.Y. Sun and A. Simonyi. Department of Biochemistry, University of Missouri-Columbia. EFFECTS OF ETHANOL AND GRAPE POLYPHENOLS ON MRNA LEVELS OF PHOSPHOLIPASE A2 IN MALE RAT BRAIN. In previous studies, it has been shown that grape polyphenols (GP) could reduced the neurodegenerative effects of ethanol on male Sprague Dawley rat brains. Our study was undertaken to examine the effects of ethanol and/or GP on phospholipase A2 (PLA2) expression. PLA2 has many functions including response to inflammatory stimuli in the brain, in this case caused by ethanol consumption. The rats were divided into four groups, each fed a different diet: control, GP supplementation, ethanol, GP and ethanol. The rats were decapitated. The brains were kept at 80[degrees]C until cut in a cryostat at 20[degrees]C. In situ hybridization was then performed using radioactively labeled probe for PLA2. An image analysis system was used to determine mRNA levels in different areas of the brain. Data analysis is still in progress. It is hoped that results from this study will further suggest the protective properties of GP in neurodegenerative diseases simulated here by ethanol. Supported by the Life Sciences Undergraduate Research Opportunities Program, University of Missouri Columbia.

Wunsch, M., S. Vasquez-Santana, A. Ippolito and T.P. Holtsford. Division of Biological Sciences, University of Missouri-Columbia. THE ROLL OF POST-POLLINATION PROCESSES IN CREATING AND MAINTAINING SPECIES DIVERSITY IN Nicotiana. Nicotiana alata, N. bonariensis and N. forgetiana are interfertile species that grow sympatrically and parapatrically throughout southern Brazil, but they form no hybrids in the wild. Pollinator discrimination does not fully explain the lack of hybridization, raising the possibility that discrimination against interspecific pollen is occurring within Nicotiana styles and ovaries after pollination. To examine the role of post-pollination processes in preventing hybridization, we performed three tests. Pollinations with 50 percent interspecific and 50 percent intraspecific pollen were completed, and the Fl progeny were grown to determine the proportion of hybrid offspring produced. Pollinations of 100 percent interspecific pollen and 100 percent intraspecific pollen were performed, and the number of seeds produced was analyzed. A second set of pollinations of 100 percent interspecific pollen and 100 percent intraspecific pollen were performed, and the styles were harvested to analyze pollen tube growth rates. A proportion of hybrid offspring below 50 percent, slower interspecific than intraspecific pollen tube growth, and reduced hybrid seed sets would suggest that discrimination against interspecific pollen is occurring. Supported by the Life Sciences Undergraduate Research Opportunities Program, University of Missouri-Columbia.

Zweifel, A., S.A. Ha, and S.F. Nothwehr. Department of Biological Sciences, University of Missouri-Columbia. CHARACTERIZATION OF THE STATIC RETENTION SIGNAL OF A YEAST GOLGI MEMBRANE PROTEIN. A-ALP, a model protein which consists of the cytoplasmic domain of dipeptidyl aminopeptidase A and the transmembrane and lumenal domains of alkaline phosphatase is a resident protein of the trans-Golgi network (TGN) in yeast. A-ALP is localized to the yeast TGN by two independent mechanisms: static retention and retrieval from a post-TGN compartment. A mutant form of AALP, called A(F-[greater than]A)-ALP is specifically defective in the retrieval mechanism and is slowly mislocalized to the vacuole where it is cleaved and becomes enzymatically activated. Previous experiments have demonstrated that the static retention signal partially resides between residues 2-11 and an A(F-[greater than],D2-11)-ALP double mutant protein is mislocalized rapidly to the vacuole. This provides evidence that a signal for the static retention mechanism exists, independent of the retrieval signal. In order to more thoroughly characterize the static retention signal, the plasmid encoding A(F-[greater than]A)-ALP was subjected to mutagenesis by PCR. The mutagenized plasmids were transformed into yeast and thc localization of the mutated A(F-[greater than]A)-ALP is currently being investigated. Supported by the Life Sciences Undergraduate Research Opportunities Program, University of MissouriColumbia.

Chemistry Section

Aide, M., K. Anderson, M. Palmieri, C. Smith, S. Tomlinson, J. Thompson, and D. Wildharber. Department of Geosciences, Southeast Missouri State University. SURVEY OF HEAVY METAL DEPOSITION ON FLOODPLAINS OF THE MISSISSIPPI RIVER. We conducted a study to determine if heavy metal deposition has occurred on floodplain soils of the Mississippi River in Cape Girardeau Co., MO. Two soil sites were selected and soil pits were excavated to classify the soils and provide samples for heavy metal contamination. Routine soil chemical characterization was supplemented with X-ray diffraction, an aqua regia digestion with ICP determination of 33 elemental concentrations and instrumental neutron activation analysis for rare earth element concentrations. Differences in soils were attributed to their natural levee and backswamp positions. In general, heavy metal contents did not appear to increase because of industrial activities and are equivalent to those contents in samples deposited prior to European settlement. Lead was t he only metal that may have slightly elevated concentrations because of human influences.

Baldwin, N. and S. Sarkar. Department of Chemistry and Physics, Central Missouri State University. CONNECTING ORCANTC CHEMISTRY THOROUGH A STUDENT DESIGNED WEB SITE. The World Wide Web is currently being used as a supplement to enhance learning of organic chemistry. The purpose of this project is two-fold: to improve upon the web designs that have been used, and to use a unique student perspective to make introductory organic chemistry more connected and student-friendly. A team approach is being used to design the site (URL: The site is constructed by a student, who has prior experience in organic chemistry, with input from the professor and from ongoing evaluations of other organic chemistry students. The site is designed in an effort to ensure ease of navigation, to supply comprehensive yet concise information, and to provide more interactive ways of learning that are compli-mentary to the textbook and the lectures. Links are provided to relevant, contextual materials to facilitate connection and to improve student attitude. This presentation will address issues regarding the selection of both the content and the method of design.

Buencamino R.B. [1] and J.J. Tanner [2]. Department of Chemistry [2] and Department of Biochemistry, [2] University of Missouri-Columbia. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is best known for its role in glycolysis, where it catalyzes the conversion of D-glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate. The trypanosomes that cause Mrican sleeping sickness, Chagas' disease, and some forms of leishmaniasis depend heavily on glycolysis for energy, thus, GAPDH is an important drug design target. Moreover, recent evidence demonstrates that mammalian GAPDH plays a role in membrane fusion microtubule bundling, phosphotransferase activity, nuclear RNA export, DNA replication and DNA repair. We are studying a thermostable GAPDH to understand the interplay of structure, function, and stability. We recently collected 1.65 A data from a frozen crystal of GAPDH with NAD bound. A second 1.8 A data set was obtained from a frozen crystal of GAPDH with NAD and phosphate bound. The structures were solved by i somorphous replacement using the room temperature 2.5 A structure. The new structures will provide information on the conformational changes caused by phosphate binding and the structural basis of thermostability. These structures are currently being refined with X--plor. Supported by the Life Sciences Undergraduate Research Opportunities Program, University of Missouri-Columbia.

Hilgenbrink, A.R., J.R. Beck and D.B. Riederer. Department of Chemistry, University of Missouri-Columbia. DISSOCIATION OF PROTONATED PEPTIDES VIA SURFACE COLLISIONS IN A TIME-OF-FLIGHT MASS SPECTROMETER. Mass spectrometry is an important tool for providing molecular weight and structural information about biomolecules. We have recently implemented the use of surface-induced dissociation (SID) in a time-of-flight mass spectrometer to obtain structural information about peptides. The dissociation of several protonated peptides/proteins, including cyclo(His-Phe), cyclo(Pro-Gly)3, bradykinin and bovine insulin, have been studied. Fragmentation was induced by colliding the parent ion into a perfluoropolyethercoated surface at energies ranging from 30-2000eV. Previous SID studies on small molecules and on peptide backbone fragments have shown that the degree of fragmentation is controlled by the collision energy. In the present study, which focuses specifically on low mass immonium ions containing amino acid side c hains, it was found that the degree of fragmentation depends on collision velocity. The collision energy ranges over which immonium ions are produced from bovine insulin (MW 5800) and cyclo(His-Phe) (MW 284) are 1000-2000eV and 65-100eV, respectively. While the collision energies are very different, both correspond to velocities in the range of 6500-8000 m/s. This suggests that the dynamics of energy transfer leading to the fragmentation of immonium ions is different from that of peptide backbone fragments. Supported hv the Life Sciences Undergraduate Research Opportunities Program, University of Missouri-Columbia.

Huang, G., S.S. Jurisson, M. Venkatesh, and J.D. Lydon. Department of Chemistry, University of Missouri-Columbia. Synthesis, characterization and radiochemistry of Au(III) complexes with tetradentate Schiff base lignads. Gold-199 (199 Au) has potential for use in radiopharmaceuticals for treating cancer because it emits both a [[beta].sup.-] particle and [gamma] ray. The [[beta].sup.-] particle has a short range over which it deposits its energy while the [gamma] ray is suitable for imaging. In this study, we investigated the chemistry and radiochemistry of Au(III) with the tetradeatate Schiff base lignads, N,N'-propylenebis(salicylideneimine) ([H.sub.2][Sal.sub.2]pn) and N,N'ethylenebis(salicylideneimine) ([H.sub.2][Sal.sub.2]en). In this initial phase of the project, we synthesized and fully characterized two Au(III) Schiff base complexes (Au[Sal.sub.2]pn]+ and [Au[Sal.sub.2]en]+), using tetrabutylammonium tetrachloroaurate (TBA-Au[Cl.sub.4]) as the starting material. We carried out radiochemical studies at t he tracer level (using [Au.sup.198]) with one of the Schiff base ligands ([H.sub.2][Sal.sub.2]pn) and the results concur with our non-radioactive Au(III) studies. We analyzed the Au(III) complexes by thin layer chromatography (TLC), infrared (IR) UV-visible, NMR spectrometry and x-ray crystallography. Both Au(III) complexes were found to be square planar four coordinate cationic complexes having the form [Au[Sal.sub.2]pn]*[PF.sub.6] and [Au[Sal.sub.2]en]*[PF.sub.6].

Kuther, S.J., H.L. Milligan, and B.S. Ross. Department of Chemistry, Cottey College. SYNTHESIS OF 4,4'-DINITROAND 4,4'-DIAMINO- DERIVATIVES OF CHAIN-TYPE POLYPHENYL COMPOUNDS. We are interested in the interaction of chain-type polyphenyl compounds with clay minerals. The purpose of this study is to develop a synthetic strategy for synthesis of aromatic chain compounds of the general formula [H.sub.2]N-[(Ph).sub.n]-[NH.sub.2] (n=3,4,5,6..). Compounds in which n = 1 and 2 are commercially available. Our recent effort is focused on the n = 4 molecule. Reaction of 4,4'-diiodobiphenyl with 4-nitrobenzoic acid in the presence of copper (I) oxide and quinoline at 220[degrees]C yields the desired 4,4'-dinitroquaterphenyl in low yield. The dinitro- compound can readily he converted to the diamineby reduction with elemental tin. Several transition metal-promoted cross-coupling reactions of aryl halides have also been investigated, with mixed results.

Mitchell, A., A. Cook and G.O. Gray. Department of Chemistry and Physics, Southwest Baptist University. SPECTROPHOTOMETRIC DETERMINATION OF THIOCYANATE IN HUMAN SALIVA AND HUMAN TEARS. Thiocyanate ([SCN.sup.1-]) is thought to confer antimicrobial activity to saliva and tear via the peroxidase-thiocyanate-hydrogenperoxide system. Other studies have shown the presence of thiocyanate (0.5-2 mM) in saliva and tear using assays of peroxidase activity or by spectrophotometric determination (saliva alone) of the red-colored Fe[SCN.sup.2+] complex. This study was conducted to determine simultaneously the [SCN.sup.1-] levels in human tear and saliva and to ascertain whether significant differences in [SCN.sup.1-] concentration existed in these two fluids. Forty-eight samples (24 male; 24 female) of human saliva and human tears were obtained from volunteer subjects and treated with Fe[([NO.sub.3]).sub.3-] containing solution. Simultaneously, a standard curve was prepared by combining known amounts of Fe([NO.sub.3]) wit h KSCN and measuring the absorbance due to formation of Fe[SCN.sup.2+]. Absorbances of the Fe[([NO.sub.3]).sub.3-] treated tear and saliva samples were compared to the standard curve to determine the Fe[SCN.sup.2+] content. Thiocyanate concentrations in the tear (5.9 mM; male and female) were determined to be 3.7-times the levels observed in saliva (1.6 mM)

Zurovac, J., H.L. Milligan, and B.S. Ross. Department of Chemistry, Cottey College. INTERCALATION OF DIAMMONIUM CHAIN-TYPE POLYPHENYL COMPOUNDS IN A SMECTITE CLAY MINERAL. We are interested in the interaction of organic molecules with phyllosilicate clay minerals. In this study, we examine the expansiveness of a smectite clay (Swy-2) upon intercalation with a series of rigid, aromatic chain compounds of the general formula [Me.sub.3]N-[(Ph).sub.n]-[[Nme.sub.3].sup.2+] (n=1,2,3,4). Intercalation of the chain compound is accomplished through displacement of Ca(II) by the aromatic diammonium cation on the Swy2 clay. The response of the clay to intercalation is monitored through x-ray diffraction spectrometry. In all cases (n=1,2,3,4) the d-space of the intercalated sample remains constant at 1 5.1A. This d-space value is of the order expected if the organic molecule is aligned with its major axis coplanar with the sheets of the smectite clay. The calculated surface area of the SWy2 clay is 175 [A.sup.2] per char ge site. Molecular modeling has been used to determine the surface area of the aromatic chain compounds to be 38, 58, 76, and 95 [A.sup.2] for n=1,2,3 and 4 respectively. These values are consistent with a coplanar alignment of the molecules with the clay sheets.

Physics Section

Fuller, B., C. Doudna, and M. Teig. Department of Physics, University of Missouri-Rolla. QUANTIZED CONDUCTANCE IN COLD NANOCONTACTS. An experiment was performed at room temperature demonstrating that nanosized contacts were created between two wires in loose contact. This resulted in quantized values of conductance in the nanocontacts. A small current on the order of 10 mA was passed through two gold wires that were brought into and out of contact with each other by means of a slight vibration. The current was converted to voltage and read on a storage oscilloscope. By this method, quantized voltages were observed on a microsecond scale during individual contact breaks. By creating a histogram of many contact breaks, conductance peaks appeared at integer multiples of 2e2/h, thus confirming the existence of nanosized contacts between the wires.

Maune, B., and C. Doudna. Department of Physics, University of Missouri-Rolla. A SURVEY OF HIGH-TEMPERATURE YBCO SUPERCONDUCTOR PROPERTIES. High-temperature [YBa.sub.2][Cu.sub.3][O.sub.7] (YBCO) superconducting pellets were fabricated and used to demonstrate three properties of superconductors. First, we investigated the force of repulsion between a superconductor and a neodymium permanent magnet by using an electronic balance. Next, we observed the Meissner effect with an AC susceptometer. Here, the magnetic flux exclusion by the superconducting pellets was detected by placing the pellets within an induction coil and by measuring the coil's change in inductance as a function of temperature. The superconductors' critical temperature was determined by an abrupt decrease in the coil's inductance. These critical temperature results are compared with results obtained via a four-point resistance measurement across the superconductors where the critical temperature is when the superconductors resistance drops to ze ro.

Stratman, C.S., B.H. Bozarth, and K.D. Winkler. Department of Physics, University of Missouri-Rolla. THERMAL HYSTERESIS IN DC RESISTIVITY OF CARBON-60 This work investigated the resistance of C60 as a function of temperature. A sample of C60 was made using a reaction chamber that would allow an electrical arc to be produced across two graphite electrodes in a 100 Ton helium environment. Production of fullerenes was confirmed by an infrared spectrum of a sample. A thin layer of C60 was placed in a slit cut into a rectangular piece of copper-coated circuit board. This board was then cooled and heated from 150K to 450K. Resistance measurements showed the presence of a dip in resistance on the order of four orders of magnitude near 290K when the sample was heated but not when it was cooled.

Zirbel, J., B. Fuller, and C. Stratman. Department of Physics, University of Missouri-Rolla. A STUDY ON THE CRYSTAL STRUCTURE AND TEXTURE OF TUNGSTEN. This paper presents an experiment that examines the crystal structure of tungsten and how it changes when annealed. Several samples of thin tungsten ribbon and tungsten mesh were heated in vacuum by passing an electric current through them. For each sample, the temperature and length of time of heating was varied. The samples were tested for crystal structure and texture using an x-ray diffractometer. The crystal structures of the samples were compared. Next, the samples were placed in the high flux gamma field of a nuclear reactor for varying amounts of time. These samples were then tested for radiation damage using an x-ray diffractometer.

Behavioral and Social Sciences Section

Morton A.M., K.A. Fischer [*] J.C. Kixmiller and P. Lall. Department of Agriculture, Central Missouri State University. PRICE ADJUSTMENT IN SOYBEAN FUTUES. The rates of adjustment of futures and cash prices to delivery-date futures price are very useful to farmers and traders in forecasting the futures price at specific delivery dates. Regression analysis was used to determine the rate of adjustment of lagged futures and current and lagged cash prices to the delivery-date futures prices of soybean using monthly data. The data set covered the period January 1996, to January 2000. One-month lags were used for both the futures and cash prices. Results indicated that for futures prices, prices lagged more that one period from the delivery date were not significant and consequently were not useful in tracking the delivery-date futures. For the cash price, up to two lags were significant. While the absolute value of the coefficient suggest that the rate of adjustment improves as the predictor price approach the del ivery-date price, there appears to be considerable variation in the prices about the expected delivery-date futures price. Similar results were obtalned for the cash prices as well. Further analysis will be done to determine whether the price variation becomes smaller and the consistency improved as the delivery-date price is approached.

Rowden, D. and K.A DeBord. Department of Social and Behavioral Sciences, Lincoln University. ASSESSING INTERVENTIONS: WHAT FACTORS AFFECT BIPHOBIA AND COLOR-BLINDNESS? Much of the published literature on college students' attitudes regarding cultural diversity has either focused on potentially influential institutional variables (e.g., whether or not an institution offers a diversity course) or upon untested classroom interventions. The current investigation responded to the gaps in the current literature by examining how a standardized course (e.g., common syllabi, common texts) on cultural diversity influenced college students' scores on a measure of covert racism (i.e., Color-Blindness) and on a scale designed to assess attitudes toward bisexuality. Pre- and post-semester data were collected from 157 students who were enrolled in either a cultural diversity course or an introductory psychology course. Results indicated that biphobia and Color-Blindness were unrelated (p [greater than] .05). Additionally, s cores on the measure of covert racism improved as a result of participation in the cultural diversity course (p [less than] .05), whereas they did not change as a result of participation in the introductory psychology course (p [greater than] .05). The reverse was true of attitudes toward bisexuality; scores improved in the introductory psychology course (p [less than] .05) and stayed the same in the cultural diversity course (p [greater than] .05). Results will be discussed in terms of course content and suggestions for curriculum improvement.

Wood, A.J., M.J. Mergen and P. Lall. Department of Agriculture, Central Missouri State University. A COMPARATIVE ANALYSIS OF SOYBEAN SUPPLY RESPONSE TO INPUT USE: MISSOURI VS. THE REST OF THE U.S. Regression analysis was used to determine the relative response of soybean supply to various production factors in the state of Missouri compared with the average response throughout the U.S. between the periods 1975 and 1999. The data consisted of annual aggregate quantity of soybean supplied for Missouri and the U.S. as a whole, and price indexes for farm supplies. A dummy variable was used to represent technological change. Results obtained indicated that the supply of soybean in Missouri was more responsive to changes in fuel price (-0.33 vs. -0.046), interest rates (-0.73 vs. -0.43), income tax (-0.46 vs. -0.069), seed price (-0.67 vs. -0.25) and the prices of farm equipment (-0.42 vs. -0.35) than the average of the states. However, Missouri is less responsive to changes in the own-price of soybean, price of fe rtilizer and the price of agro-chemical than the average of the states. The results also indicated that Missouri farms were more responsive to technological changes and farm supply was greater in larger farms in Missouri than the average of the states.
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Publication:Transactions of the Missouri Academy of Science
Date:Jan 1, 1999
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