Digital Commons Network^™

Effects Of M-Tyrosine On Feeding And Survival Of Formosan Subterranean Termites (Isoptera: Rhinotermitidae), Bal K. Gautam, Gregg Henderson

Faculty Publications

Amino acids are important to all animal life. Termites rely mainly on microorganisms to retrieve these nitrogen sources from their food. One naturally occurring amino acid, m-tyrosine, has been reported to be toxic to bacteria and weeds. Its direct effects on termite survival are unknown however. Both no-choice and choice bioassays using five different doses of m-tyrosine were conducted to determine the feeding response and survival of Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in the laboratory. In no-choice tests, although all doses of m-tyrosine tested reduced filter paper consumption, only the highest dose tested (0.05 M) had significantly …

Dietary Resistant Starch Upregulates Total Glp-1 And Pyy In A Sustained Day-Long Manner Through Fermentation In Rodents, June Zhou, Roy J. Martin, Richard T. Tulley, Anne M. Raggio, Kathleen L. Mccutcheon, Li Shen, Samuel Colby Danna, Sasmita Tripathy, Maren Hegsted, Michael J. Keenan

Faculty Publications

Glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) are anti-diabetes/obesity hormones ecreted from the gut after meal ingestion. We have shown that dietary-resistant starch (RS) increased GLP-1 and PYY secretion, but he mechanism remains unknown. RS is a fermentable fiber that lowers the glycemic index of the diet and liberates short-chain fatty acids (SCFAs) through fermentation in the gut. This study investigates the two possible mechanisms by which RS stimulates GLP-1 and PYY secretion: the effect of a meal or glycemic index, and the effect of fermentation. Because GLP-1 and PYY secretions are stimulated by nutrient availability in the gut, the …

A Competitive Hybridization Model Predicts Probe Signal Intensity On High Density Dna Microarrays, Shuzhao Li, Alex Pozhitkov, Marius Brouwer

Faculty Publications

A central, unresolved problem of DNA microarray technology is the interpretation of different signal intensities from multiple probes targeting the same transcript. We propose a competitive hybridization model for DNA microarray hybridization. Our model uses a probe-specific dissociation constant that is computed with current nearest neighbor model and existing parameters, and only four global parameters that are fitted to Affymetrix Latin Square data. This model can successfully predict signal intensities of individual probes, therefore makes it possible to quantify the absolute concentration of targets. Our results offer critical insights into the design and data interpretation of DNA microarrays.

Breast Cancer Fatalism: The Role Of Women's Perceptions Of The Health Care System, Allyson G. Hall, Amal J. Khoury, Ellen D.S. Lopez, Nedra Lisovicz, Amanda Avis-Williams, Amal K. Mitra

Faculty Publications

Cancer fatalism, which can be understood as the belief that cancer is a death sentence, has been found to be a deterrent to preventive cancer screening participation. This study examines factors associated with breast cancer fatalism among women. We analyzed data from a 2003 survey of women 40 years of age. The survey collected information about respondents' knowledge and attitudes regarding breast health. Analyses compared the characteristics of women who reported and those who did not report a fatalistic attitude. Women with a fatalistic attitude were more likely to be African American, to have a family history of breast cancer, …

Numerical Simulation Of Local Temperature Distortions During Ice Nucleation Of Cells In Suspension, D. Kandra, R. V. Devireddy

Faculty Publications

Knowledge of intercellular ice formation in cells embedded in an extra-cellular suspension is essential for effective design of freezing protocols. The presence of cell membrane causes super-cooling of the intra-cellular region, which nucleates at much lower temperatures than the surrounding extra-cellular space and is accompanied by the exothermic release of the latent heat. This is a dynamic process and causes thermal distortions in and around the cell where nucleation occurs. In the present study, an attempt has been made to numerically determine the magnitude of thermal distortion (ΔT) and the time (dt) it takes for this distortion to damp out …

Neuroimaging And Recovery Of Language In Aphasia, Cynthia K. Thompson, Dirk B. Den Ouden

Faculty Publications

The use of functional neuroimaging techniques has advanced what is known about the neural mechanisms used to support language processing in aphasia resulting from brain damage. This paper highlights recent findings derived from neuroimaging studies focused on neuroplasticity of language networks, the role of the left and right hemispheres in this process, and studies examining how treatment affects the neurobiology of recovery. We point out variability across studies as well as factors related to this variability, and we emphasize challenges that remain for research.

Cardiorespiratory Fitness As A Predictor Of Fatal And Nonfatal Stroke In Asymptomatic Women And Men, Steven P. Hooker, Xuemei Sui, Natalie Colabianchi, John E. Vena, James N. Laditka, Michael J. Lamonte, Steven N. Blair

Faculty Publications

Background and Purpose - Prospective data on the association between cardiorespiratory fitness (CRF) and stroke are largely limited to studies in men or do not separately examine risks for fatal and nonfatal stroke. This study examined the association between CRF and fatal and nonfatal stroke in a large cohort of asymptomatic women and men.

Methods - A total of 46,405 men and 15,282 women without known myocardial infarction or stroke at baseline completed a maximal treadmill exercise test between 1970 and 2001. CRF was grouped as quartiles of the sex-specific distribution of maximal metabolic equivalents achieved. Mortality follow-up was through …

Restoration Of Dredged Canals In Wetlands: A Comparison Of Methods, Joseph Baustian, R. Eugene Turner, Nancy F. Walters, David P. Muth

Faculty Publications

A comparison of two methods for restoring dredged canals to wetlands was examined at the Jean Lafitte National Historical Park and Preserve’s Barataria Preserve Unit near New Orleans, LA. Both northern and southern canals had the remnant dredged spoil material returned to the canal, but the southern canal had additional sediment pumped in from a nearby lake. The water depth in the southern canal shallowed significantly from 1.2 to 0.4 m following backfilling and sediment addition, while the depth of the northern canal (which received no additional sediment) remained unchanged following backfilling. Neither site had complete soil restoration, but the …

Halothiobacillus Neapolitanus Carboxysomes Sequester Heterologous And Chimeric Rubisco Species, Balaraj B. Menon, Zhicheng Dou, Sabine Heinhorst, Jessup M. Shively, Gordon C. Cannon

Faculty Publications

Background: The carboxysome is a bacterial microcompartment that consists of a polyhedral protein shell filled with ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), the enzyme that catalyzes the first step of CO(2) fixation via the Calvin-Benson-Bassham cycle. Methodology/Principal Findings: To analyze the role of RubisCO in carboxysome biogenesis in vivo we have created a series of Halothiobacillus neapolitanus RubisCO mutants. We identified the large subunit of the enzyme as an important determinant for its sequestration into alpha-carboxysomes and found that the carboxysomes of H. neapolitanus readily incorporate chimeric and heterologous RubisCO species. Intriguingly, a mutant lacking carboxysomal RubisCO assembles empty carboxysome shells of …

The Psbo1 Mutant Of Arabidopsis Cannot Efficiently Use Calcium In Support Of Oxygen Evolution By Photosystem Ii, Terry M. Bricker, Laurie K. Frankel

Faculty Publications

The Arabidopsis thaliana mutant psbo1 contains a point mutation in the psbO-1 gene (At5g66570) leading to the loss of expression of the PsbO-1 protein and overexpression of the PsbO-2 protein (Murakami, R., Ifuku, K., Takabayashi, A., Shikanai, T., Endo, T., and Sato, F. (2002) FEBS Lett. 523, 138-142). Previous characterization of fluorescence induction and decay kinetics by our laboratory documented defects on both the oxidizing and reducing sides of Photosystem II. Additionally, anomalous flash oxygen yield patterns indicated that the mutant contains a defective oxygen-evolving complex that appears to exhibit anomalously long-lived S2 and S3 oxidation states (Liu, H., Frankel, …

Assessment Of Clear And Cloudy Sky Parameterizations For Daily Downwelling Longwave Radiation Over Different Land Surfaces In Florida, Usa, Minha Choi, Jennifer M. Jacobs, William P. Kustas

Faculty Publications

Clear sky downwelling longwave radiation (Rldc) and cloudy sky downwelling longwave radiation (Rld) formulas were tested across eleven sites in Florida. The Brunt equation, using air vapor pressure and temperature measurements, provides the best Rldc estimates with a root mean square error of less than around 12 Wm−2 across all sites. The Crawford and Duchon's cloudiness factor with Brunt equation is recommended for Rld calculations. This combined approach requires no local calibration and estimates Rld with a root mean square error of less than around 13 Wm−2 and squared correlation coefficients that typically exceed 0.9.

Crystal Structure Of Fosfomycin Resistance Kinase Foma From Streptomyces Wedmorensis, Svetlana Pakhomova, Sue G. Bartlett, Alexandria Augustus, Tomohisa Kuzuyama, Marcia E. Newcomer

Faculty Publications

The fosfomycin resistance protein FomA inactivates fosfomycin by phosphorylation of the phosphonate group of the antibiotic in the presence of ATP and Mg(II). We report the crystal structure of FomA from the fosfomycin biosynthetic gene cluster of Streptomyces wedmorensis in complex with diphosphate and in ternary complex with the nonhydrolyzable ATP analog adenosine 5′-(β,γ-imido)-triphosphate (AMPPNP), Mg(II), and fosfomycin, at 1.53 and 2.2 Å resolution, respectively. The polypeptide exhibits an open αβα sandwich fold characteristic for the amino acid kinase family of enzymes. The diphosphate complex shows significant disorder in loops surrounding the active site. As a result, the nucleotide-binding site …

Characterization Of A Site On Pai-1 That Binds To Vitronectin Outside Of The Somatomedin B Domain, Christine R. Schar, Jan K. Jensen, Anni Christensen, Grant E. Blouse, Peter A. Andreasen, Cynthia B. Peterson

Faculty Publications

Vitronectin and plasminogen activator inhibitor-1 (PAI-1) are proteins that interact in the circulatory system and pericellular region to regulate fibrinolysis, cell adhesion, and migration. The interactions between the two proteins have been attributed primarily to binding of the somatomedin B (SMB) domain, which comprises the N-terminal 44 residues of vitronectin, to the flexible joint region of PAI-1, including residues Arg-103, Met-112, and Gln-125 of PAI-1. A strategy for deletion mutagenesis that removes the SMB domain demonstrates that this mutant form of vitronectin retains PAI-1 binding (Schar, C. R., Blouse, G. E., Minor, K. M., and Peterson, C. B. (2008) J. …

Sugary Soda Consumption And Albuminuria: Results From The National Health And Nutrition Examination Survey, 1999-2004, David A. Shoham, Ramon Durazo-Arvizu, Holly Kramer, Amy Luke, Suma Vupputuri, Abhijit Kshirsagar, Richard S. Cooper

Faculty Publications

Background: End-stage renal disease rates rose following widespread introduction of high fructose corn syrup in the American diet, supporting speculation that fructose harms the kidney. Sugar-sweetened soda is a primary source of fructose. We therefore hypothesized that sugary soda consumption was associated with albuminuria, a sensitive marker for kidney disease. Methodology/Principal Findings: Design was a cross-sectional analysis. Data were drawn from the National Health and Nutrition Examination Survey (NHANES), 1999-2004. The setting was a representative United States population sample. Participants included adults 20 years and older with no history of diabetes mellitus (n = 12,601); after exclusions for missing outcome …

Calculating Expected Dna Remnants From Ancient Founding Events In Human Population Genetics, Nathan C. Sheffield, Keith A. Crandall, Andrew Stacey

Faculty Publications

Background- Recent advancements in sequencing and computational technologies have led to rapid generation and analysis of high quality genetic data. Such genetic data have achieved wide acceptance in studies of historic human population origins and admixture. However, in studies relating to small, recent admixture events, genetic factors such as historic population sizes, genetic drift, and mutation can have pronounced effects on data reliability and utility. To address these issues we conducted genetic simulations targeting influential genetic parameters in admixed populations. Results- We performed a series of simulations, adjusting variable values to assess the affect of these genetic parameters on current …

Drought Stress And Preharvest Aflatoxin Contamination In Agricultural Commodity: Genetics, Genomics And Proteomics, Baozhu Guo, Zhi Yuan Chen, R. Dewey Lee, Brian T. Scully

Faculty Publications

Throughout the world, aflatoxin contamination is considered one of the most serious food safety issues concerning health. Chronic problems with preharvest aflatoxin contamination occur in the southern US, and are particularly troublesome in corn, peanut, cottonseed, and tree nuts. Drought stress is a major factor to contribute to preharvest aflatoxin contamination. Recent studies have demonstrated higher concentration of defense or stress-related proteins in corn kernels of resistant genotypes compared with susceptible genotypes, suggesting that preharvest field condition (drought or not drought) influences gene expression differently in different genotypes resulting in different levels of "end products": PR(pathogenesis-related) proteins in the mature …

Genome-Wide Association Studies: Implications For Multiethnic Samples, Richard S. Cooper, Bamidele Tayo, Xiaofeng Zhu

Faculty Publications

The current gene mapping for complex diseases is heavily weighted by studies of population samples from northern Europe. To capture the full range of genetic diversity and exploit the potential of genetic epidemiology to identify important variants, multiple additional populations will need to be examined. The conduct of genome-wide association studies will therefore confront many of the challenges identified in the first generation of candidate gene and linkage studies, with a substantial increase in complexity. Initial efforts to map causal effects will have to take account of varying patterns of linkage disequilibrium through careful attention to local haplotype structure. Refined …

Conservation And Conflict Between Endangered Desert Fishes, Jennifer M. Gumm, Jennifer L. Snekser, Murray Itzkowitz

Faculty Publications

Conservation of naturally sympatric endangered species requires unique considerations. While impacts of invasive species garner much attention, interactions between endangered species must also be managed. The endangered Leon Springs pupfish, Cyprinodon bovinus, has suffered a population decline due to decreasing natural habitat. As breeding habitat is lost, C. bovinus is also adversely affected by the sympatric, endangered Pecos gambusia, Gambusia nobilis. Here, we document interactions between these species, finding significantly more G. nobilis accumulated at pupfish spawning events than randomly distributed on breeding grounds in the absence of spawning. As a known egg predator, our results suggest that G. nobilis …

A Covalent Linker Allows For Membrane Targeting Of An Oxylipin Biosynthetic Complex, Nathaniel C. Gilbert, Marc Niebuhr, Hiro Tsuruta, Tee Bordelon, Oswin Ridderbusch, Adam Dassey, Alan R. Brash, Sue G. Bartlett, Marcia E. Newcomer

Faculty Publications

A naturally occurring bifunctional protein from Plexaura homomalla links sequential catalytic activities in an oxylipin biosynthetic pathway. The C-terminal lipoxygenase (LOX) portion of the molecule catalyzes the transformation of arachidonic acid (AA) to the corresponding 8R-hydroperoxide, and the N-terminal allene oxide synthase (AOS) domain promotes the conversion of the hydroperoxide intermediate to the product allene oxide (AO). Small-angle X-ray scattering data indicate that in the absence of a covalent linkage the two catalytic domains that transform AA to AO associate to form a complex that recapitulates the structure of the bifunctional protein. The SAXS data also support a model for …

Black Bears On The Way Back, Christopher E. Comer

Faculty Publications

No abstract provided.

Red-Cockaded Woodpeckers And Hurricanes, Zoe Hoyle

Faculty Publications

No abstract provided.

Weight Regain Is Related To Decreases In Physical Activity During Weight Loss, Xuewen Wang, Mary F. Lyles, Tongjian You, Michael J. Berry, Jack Rejeski, Barbara J. Nicklas

Faculty Publications

Purpose—To examine whether adaptations in physical activity energy expenditure (PAEE) and resting metabolic rate (RMR) during weight loss were associated with future weight regain in overweight/obese, older women.

Research Methods and Procedures—Thirty-four overweight/obese (BMI=25–40 kg/m²), postmenopausal women underwent a 20-week weight loss intervention of hypocaloric diet with (low- or high-intensity) or without treadmill walking (weekly caloric deficit was ~11760 kJ), with a subsequent 12-month follow-up. RMR (via indirect calorimetry), PAEE (by RT3 accelerometer) and body composition (by DXA) were measured before and after intervention. Body weight and self-reported information on physical activity were collected after intervention, …

What Is Urban Health Policy And What's Law Got To Do With It?, Larry I. Palmer

Faculty Publications

No abstract provided.

Toll-Like Receptor 2 Recognition Of The Microsporidia Encephalitozoon Spp. Induces Nuclear Translocation Of Nf-Κb And Subsequent Inflammatory Responses, Jeffrey Fischer, Colby Suire, Hollie Hale-Donze

Faculty Publications

Microsporidia are obligate intracellular parasites that are ubiquitous in nature and have been recognized as causing an important emerging disease among immunocompromised individuals. Limited knowledge exists about the immune response against these organisms, and virtually nothing is known about the receptors involved in host recognition. Toll-like receptors (TLR) are pattern recognition receptors that bind to specific molecules found on pathogens and signal a variety of inflammatory responses. In this study, we show that both Encephalitozoon cuniculi and Encephalitozoon intestinalis are preferentially recognized by TLR2 and not by TLR4 in primary human macrophages. This is the first demonstration of host receptor …

Brassicaceae Phylogeny Inferred From Phytochrome A And Ndhf Sequence Data: Tribes And Trichomes Revisited, Mark A. Beilstein, Ihsan A. Al-Shehbaz, Sarah Mathews, Elizabeth A. Kellogg

Faculty Publications

The family Brassicaceae comprises 3710 species in 338 genera, 25 recently delimited tribes, and three major lineages based on phylogenetic results from the chloroplast gene ndhF. To assess the credibility of the lineages and newly delimited tribes, we sequenced an approximately 1.8-kb region of the nuclear phytochrome A (PHYA) gene for taxa previously sampled for the chloroplast gene ndhF. Using parsimony, likelihood, and Bayesian methods, we reconstructed the phylogeny of the gene and used the approximately unbiased (AU) test to compare phylogenetic results from PHYA with findings from ndhF. We also combined ndhF and PHYA data and used a Bayesian …

Jamaican Nightshade (Solanum Jamaicense): A Threat To Florida's Hammocks, Rodrigo Diaz, William A. Overholt, Kenneth Langeland

Faculty Publications

Jamaican nightshade is a prickly, perennial, invasive shrub in central and southern peninsular Florida. It was first seen in Florida in 1930 near St. Cloud, and has since been reported at several other locations in the state. Jamaican nightshade is primarily found in wooded habitats, where it can quickly become dominant in the understory, but it also occasionally grows in isolated patches in the open. Although the distribution of Jamaican nightshade does not appear to be rapidly expanding in Florida, land mangers should be made aware of the potential of this weed to establish at new sites, and initiate control …

Comparison Of Species Tree Methods For Reconstructing The Phylogeny Of Bearded Manakins (Aves: Pipridae, Manacus) From Multilocus Sequence Data, Robb T. Brumfield, Liang Liu, David E. Lum, Scott V. Edwards

Faculty Publications

Although the power of multi-locus data in estimating species trees is apparent, it is also clear that the analytical methodologies for doing so are still maturing. For example, of the methods currently available for estimating species trees from multiocus data, the Bayesian method introduced by Liu and Pearl (2007; BEST) is the only one that provides nodal support values. Using gene sequences from five nuclear loci, we explored two analytical methods (deep coalescence and BEST) to reconstruct the species tree of the five primary Manacus OTUs: M. aurantiacus, M. candei, M. vitellinus, populations of M. manacus from west of the …

Haldane's Rule In An Avian System: Using Cline Theory And Divergence Population Genetics To Test For Differential Introgression Of Mitochondrial, Autosomal, And Sex-Linked Loci Across The Passerina Bunting Hybrid Zone, Matthew D. Carling, Robb T. Brumfield

Faculty Publications

Using cline fitting and divergence population genetics, we tested a prediction of Haldane's rule: autosomal alleles should introgress more than z-linked alleles or mitochondrial haplotypes across the Passerina amoena/Passerina cyanea (Aves: Cardinalidae) hybrid zone. We screened 222 individuals collected along a transect in the Great Plains of North America that spans the contact zone for mitochondrial (two genes), autosomal (four loci) and z-linked (two loci) markers. Maximum-likelihood cline widths estimated from the mitochondrial (223 km) and z-linked (309 km) datasets were significantly narrower on average than the autosomal cline widths (466 km). We also found that mean coalescent-based estimates of …

Rapid Comparison Of Properties On Protein Surface, Lee Sael, David La, Bin Li, Raif Rustamov, Daisuke Kihara

Faculty Publications

The mapping of physicochemical characteristics onto the surface of a protein provides crucial insights into its function and evolution. This information can be further used in the characterization and identification of similarities within protein surface regions. We propose a novel method which quantitatively compares global and local properties on the protein surface. We have tested the method on comparison of electrostatic potentials and hydrophobicity. The method is based on 3D Zernike descriptors, which provides a compact representation of a given property defined on a protein surface. Compactness and rotational invariance of this descriptor enable fast comparison suitable for database searches. …

Field-Evolved Resistance To Bt Toxins, Willam Moar, Rick Roush, Anthony Shelton, Juan Ferré, Susan Macintosh, B. Rogers Leonard, Craig Abel

Faculty Publications

No abstract provided.