Digital Commons Network^™

Fundamental Contribution Of Β-Oxidation To Polyketide Mycotoxin Production In Planta, Lori A. Maggio-Hall, Richard A. Wilson, Nancy P. Keller

Fungal Molecular Plant-Microbe Interactions

Seed contamination with polyketide mycotoxins, including aflatoxin (AF) and sterigmatocystin (ST) produced by Aspergillus spp., is an agricultural, economic, and medical issue worldwide. Acetyl-CoA, the fundamental building block of all known fungal polyketides, is generated by a large number of biochemical pathways, including β-oxidation of fatty acids and glycolysis of sugars. We present several lines of evidence to support a major role for seed fatty acids in formation of AF and ST in A. flavus, A. parasiticus, and A. nidulans. Aspergillus strains exhibiting canonical signs of oleic acid–induced peroxisome proliferation, including increased catalase activity, β-oxidation gene expression, and …

Genome Sequences Of Agropyron Mosaic Virus And Hordeum Mosaic Virus Support Reciprocal Monophyly Of The Genera Potyvirus And Rymovirus In The Family Potyviridae, Roy C. French, D.C. Stenger

Department of Plant Pathology: Faculty Publications

Assignment of mite-transmitted species to the genus Rymovirus (family Potyviridae) has changed several times, and the status of the genus has been questioned. To address this issue, complete genome sequences of the rymoviruses Agropyron mosaic virus (AgMV) and Hordeum mosaic virus (HoMV) were determined. AgMV (9540 nucleotides) and HoMV (9463 nucleotides) each encode a single polyprotein with proteinase cleavage sites demarcating protein products characteristic of monopartite species of the family Potyviridae. Of the described species of Potyviridae, AgMV and HoMV are most closely related to each other (68.5% nucleotide and 71.6% amino acid sequence identity) and equidistant …

Field Assessment Of The Risk Posed By Diorhabda Elongata, A Biocontrol Agent For Control Of Saltcedar (Tamarix Spp.), To A Nontarget Plant, Frankenia Salina, Tom L. Dudley, David J. Kazmer

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The biological control program for saltcedar (Tamarix spp.) has led to open releases of a specialist beetle (Chrysomelidae: Diorhabda elongata) in several research locations, but the controversy over potential impacts to native, nontarget plants of the genus Frankenia remains unresolved. To assess the potential for nontarget impacts under Weld conditions, we installed cultivated Frankenia spp. (primarily two forms of Frankenia salina but also including Frankenia jamesii) at locations in Nevada and Wyoming where D. elongata densities and saltcedar defoliation were expected to be very high, so insects would be near starvation with high probability of attacking nontargets …

Weed Suppression By Deleterious Rhizobacteria Is Affected By Formulation And Soil Properties, Robert E. Zdor, Carlene M. Alexander, Robert J. Kremer

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Deleterious rhizobacteria (DRB) suppress weed growth in field tests and are considered potential weed biological control agents. This study compared the relative inhibitory action of the DRB Pseudomonas fluorescens strain G2-11 in different formulations, corn gluten meal (CGM), and semolina flour, toward wheat (Triticum aestivum L.), green foxtail (Setaria viridis (L.) Beauv.), and velvetleaf (Abutilon theophrasti Medik) seeds and seedlings in soil assays. Strain G2-11 successfully established in semolina flour as an inoculum formulation but was incompatible with CGM presumably because of antibacterial factors present. The effect of DRB and plant products on seed germination and plant …

Winter Feeding Sites Of Hay In Round Bales As Major Developmental Sites Of Stomoxys Calcitrans (Diptera: Muscidae) In Pastures In Spring And Summer, Alberto B. Broce, Jerome Hogsette, Steven Paisley

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The stable fly, Stomoxys calcitrans (L.), historically has been a pest of livestock in confined operations but seldom of animals on pastures or rangelands. In the past two decades, however, S. calcitrans has become a major pest of cattle and horses on pastures in the midwestern United States. Although there usually is an overabundance of diverse stable fly and house fly, Musca domestica L., larval habitats in confined livestock operations, no larval habitat for stable flies has been clearly identified in the pasture-range environment. Because the winter feeding of hay in round bales results in significant amounts of hay wastage …

Effect Of Control Plot Density, Control Plot Arrangement, And Assumption Of Random Or Fixed Effects On Nonreplicated Experiments For Germplasm Screening Using Spatial Models, Boi Sebolai, Jeffrey F. Pedersen, D. B. Marx, D. L. Boykin

Department of Agronomy and Horticulture: Faculty Publications

Early generation selection experiments typically involve several hundred to thousands of lines. Various systematic and statistical techniques have been developed to increase effectiveness and efficiencies in such experiments, including the development and application of spatial statistical models. In this study, mixed model equations were used to provide least squares means (LSMEANs) and best linear unbiased predictors (BLUPs) and compare selection effectiveness and efficiencies to observed (Y) and true values in simulated experiments varying in size (10 X 10, 20 X 20 and 30 X 30 grids), control plots densities (0, 5, 10, 20, and 50%), control plot arrangements (high, medium, …

Review Of The Black Flies (Simuliidae) Of North America By: Peter H Adler, Douglas C Currie, And D Monty Wood, Jerome Hogsette

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Based on its title, one could expect this volume to be mainly a taxonomic reference for the North American Black Flies, but it is actually much more. The book is organized into five parts, each containing two to three of the 10 total chapters. Part I presents a very comprehensive overview of the subject (Chapter 1), followed by a history of the research (Chapter 2) that contains good historical references, as well as citations that are quite recent. Historical references are always welcome in any review section because they may have been published in regional or local literature that are …

Predicting Plant Extinction Based On Species-Area Curves In Prairie Fragments With High Beta Richness, Brian J. Wilsey, Leanne M. Martin, H. Wayne Polley

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Species-area relationships and island biogeography theory are commonly used to predict how species richness will decline with fragmentation. There are a variety of largely untested assumptions in these approaches, including the assumptions that populations are distributed uniformly before fragmentation, and that local extinctions are due to effects of small population sizes. If populations are not distributed uniformly, then populations can be abundant locally but rare globally. This would cause extinction rates to be smaller than predicted.We tested extinction theory by developing estimates of the number of plant species that should be present in small tallgrass prairie fragments and then testing …

Patterns Of Plant Species Diversity In Remnant And Restored Tallgrass Prairies, H. Wayne Polley, Justin D. Derner, Brian J. Wilsey

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

To restore diversity of native vegetation, we must understand factors responsible for diversity in targeted communities. These factors operate at different spatial scales and may affect the number and relative abundances of species differently. We measured diversity of plant species and functional groups of species in replicated plots within paired restored and remnant (relic) tallgrass prairies at three locations in central Texas, U.S.A.

A Modified Molybdenum Blue Method For Orthophosphate Determination Suitable For Investigating Enzymatic Hydrolysis Of Organic Phosphates, Zhongqi He, C. Wayne Honeycutt

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In characterizing organic phosphorus (P_o) by phosphatase hydrolysis, the quantity of hydrolyzable P_o is represented by the difference in orthophosphate [i.e., inorganic P (P_i)] determined after and prior to enzymatic incubation. Therefore, precise determination of P_i is of major importance for accurate application of the enzymatic hydrolysis approach. The strong acid conditions required for conventional molybdenum blue methods interferes with P_i determination due to rapid hydrolysis of labile P_o and precipitation of enzymes (proteins). The molybdenum blue method of Dick and Tabatabai in 1977 reduced errors pertaining to nonenzymatic hydrolysis of P …

Comparison Of Protein Solubilization Methods Suitable For Proteomic Analysis Of Soybean Seed Proteins, Savithiry Natarajan, Chenping Xu, Thomas J. Caperna, Wesley M. Garrett

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Extraction of soybean seed proteins for two-dimensional polyacrylamide gel electrophoresis (2D–PAGE) and mass spectrometry analysis is challenging and inconsistent. In this study, we compared four different protein extraction/solubilization methods—urea, thiourea/urea, phenol, and a modified trichloroacetic acid (TCA)/acetone—to determine their efficacy in separating soybean seed proteins by 2D–PAGE. In all four methods, seed storage proteins were well separated by 2D–PAGE with minor variations in the intensity of the spots. The thiourea/urea and TCA methods showed higher protein resolution and spot intensity of all proteins compared with the other two methods. In addition, several less abundant and high molecular weight proteins were …

Size-Dependent Feeding And Reproduction By Boll Weevil (Coleoptera: Curculionidae), S. M. Greenberg, D. W. Spurgeon, Thomas W. Sappington, M. Sétamou

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The considerable variation in adult size of the boll weevil, Anthonomus grandis grandis Boheman, has been well documented, but the influences of adult size on reproductive rate are not known. We examined the relationship between the size of boll weevils and their feeding and oviposition. Weevils weighed to the nearest milligram were grouped into five categories based on pupal weight:≤5, 6-10, 11-15, 16-20, and>20 mg. Numbers of lifetime punctures produced in flower buds (squares) of cotton, Gossypium hirsutum L., by both sexes of adults tended to increase with pupal weight. Boll weevil females with pupal weights >10 mg produced …

Comparison Of Contact And Spatial Repellency Of Catnip Oil And N,N-Diethyl-3-Methylbenzamide (Deet) Against Mosquitoes, Ulrich R. Bernier, Kay D. Furman, Daniel L. Kline, Sandra A. Allan, Donald R. Barnard

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Nepetalactone, the primary component of catnip oil, was compared with the repellent N,N-diethyl-3-methylbenzamide (deet) for its ability to affect the host-seeking ability of Aedes aegypti (L.). A triple cage olfactometer was used to bioassay each substance and to assess its attraction inhibition (spatial repellent) attributes when combined with the following attractants: carbon dioxide, acetone, a blend of L-lactic acid and acetone, and human odors. Repellent tests were conducted with each substance against female Ae. aegypti, Anopheles albimanus Weidemann, and Anopheles quadrimaculatus Say. Catnip oil and deet were both weakly attractive to Ae. aegypti, catnip oil was the better spatial …

Habitat Corridors Function As Both Drift Fences And Movement Conduits For Dispersing Flies, Joanna H. Fried, Douglas J. Levey, Jerome Hogsette

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Corridors connect otherwise isolated habitat patches and can direct movement of animals among such patches. In eight experimental landscapes, we tested two hypotheses of how corridors might affect dispersal behavior. The Traditional Corridor hypothesis posits that animals preferentially leave patches via corridors, following them into adjacent patches. The Drift Fence hypothesis posits that animals dispersing through matrix habitat are diverted into patches with corridors because they follow corridors when encountered. House flies (Musca domestica L.), a species that prefers the habitat of our patches and corridors, were released in a central patch (100x100 m) and recaptured in peripheral patches …

Post-Release Evaluation Of Biological Control Of Bemisia Tabaci Biotype ‘‘B’’ In The Usa And The Development Of Predictive Tools To Guide Introductions For Other Countries, John A. Goolsby, Paul J. Debarro, Alan A. Kirk, Robert W. Sutherst, Luis Canas, Matthew A. Ciomperlik, Peter C. Ellsworth, Juli R. Gould, Diana M. Hartley, Kim A. Hoelmer, Steven E. Naranjo, Mike Rose, William J. Roltsch, Paul A. Ruiz, Charles H. Pickett, Don C. Vacek

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Climatic matching and pre-release performance evaluation were useful predictors of parasitoid establishment in a retrospective analysis of a classical biological control program against Bemisia tabaci biotype ‘‘B’’ in the USA. Laboratory evaluation of 19 imported and two indigenous parasitoid species in quarantine on B. tabaci showed that the Old World Eretmocerus spp, had the highest attack rate. The climate matching program CLIMEX was used to analyze the establishment patterns of five Old World Eretmocerus spp. introduced to the Western USA. The top matches ±10% for the climate of the area of introduction and origin of the introduced parasitoids always included …

2005 Virginia Wildflower Of The Year: Bloodroot, Sanguinaria Canadensis, W. John Hayden

Biology Faculty Publications

Bloodroot is an herbaceous perennial that grows from a persistent, branched underground stem or rhizome. Early each spring, while the forest canopy is still bare, each well-developed rhizome tip produces one leaf and one flower stalk. The leaf is kidney-shaped in its overall outline, but it is also divided into a pattern of rounded lobes and sinuses, rendering a complex overall shape. At flowering time, bloodroot leaves form a loose vertically-oriented collar around the flower stalk with the bluish-green lower leaf surface forming the outside of the collar; as the season progresses, the leaves open flat and expand to their …

Development Of A Process Of Addition Of Tricalcium Phosphate From Burnt Phosphate Rock In Feed For Animal Nutrition, Luis Fernando Nogales Grágeda

Theses and Dissertations

This study took place in Bolivia with the purpose of using thermally treated Capinota phosphate rock as a phosphorous supplement in balanced feed diets. The objective was to produce a natural phosphate substance that would be more easily accessible to the local population than commercial feed supplements. An additional objective of this study was to increase the availability of the low-fluoride phosphorous. The biological assays indicated that the diet with the added burned phosphoric rock produced similar yields to those using a commercial feed supplement (dicalcium phosphate). This indicates that the locally manufactured product, by partial acidification, can compete with …

The Role Of Peroxidases In The Development Of Plants And Their Responses To Abiotic Stresses., Deborah Vicuna

Doctoral

Peroxidases and its effects on plants were analysed. Peroxidases are involved in many physiological processes in plants, involving responses to biotic and abiotic stresses and the biosynthesis of lignin. Liglin is a polymer responsible for rendering the plant stronger and more rigid and also making the cell walls hydrophobic. Peroxidases are involved in the polymerization of the precursors of lignin. They are also involved in the scavenging of Reactive Oxygen Species (ROS), which are partially reduced forms of atmospheric oxygen, highly reactive, and capable of causing oxidative damage to the cell. Peroxidases can be a source of hydrogen peroxide (H2O2) …

Genetic Variation In Ustilago Bullata: Molecular Genetic Markers And Virulence On Bromus Tectorum Host Lines, Mikel Stevens, Daniel J. Fairbanks, Susan E. Meyer, David L. Nelson, Suzette Clement, Jennifer Waters

Faculty Publications

The pathogen Ustilago bullata often causes epidemic levels of head smut disease in Intermountain populations of the inbreeding annual grass Bromus tectorum. We examined patterns of genetic variation for virulence and for amplified fragment length polymorphism (AFLP) markers in four U. bullata populations on B. tectorum in northern Utah and southern Nevada. Patterns of disease incidence generally supported a genefor-gene model for virulence and resistance in this pathosystem. Most host lines were susceptible to most or all paired isolates included in cross-inoculation tests, but we found evidence for the existence of four avirulence genes. Host lines with alleles conferring resistance …

Seasonal Acceptance Of Fourwing Saltbush By Sheep When Crested Wheatgrass Is The Alternative, Val J. Anderson, R. D. Horrocks, Christine W. Royer, Stephen B. Monsen

Faculty Publications

Many sagebrush-grass ranges have been seeded to crested wheatgrass [Agropyron desertorum (Fischer ex Link) Shultes]. These ranges are generally nutritionally inadequate for sheep (Ovis aries L.), except for short grazing periods in the spring and fall. To increase production and diversity, particularly crude protein for late-season grazing, fourwing saltbush [Atriplex canescens (Pursch.) Nutt.] was planted in an existing stand of crested wheatgrass. Quantification of sheep forage preferences on these improved ranges aids in determining the length of the grazing season and the extent to which shrubs provide the supplemental nutrition required. This seasonal grazing study was conducted on a characteristic …

Agrostology; An Introduction To The Systematics Of Grasses, James P. Smith Jr

Botanical Studies

No abstract provided.

Preparations Of Spherical Polymeric Particles From Tanzanian Cashew Nut Shell Liquid By Suspension Polymerization, L L Mkayula, Y M M Makame, T H Matechi

Tanzania Journal of Science

Spherical Polymeric Particles (SPP) have been prepared from Tanzanian Cashew Nut Shell Liquid (CNSL) by suspension polymerization technique involving either step-growth or chain- growth polymerization mechanisms. The sizes of the SPP, which ranged from 0.1 to 2.0 mm were strongly influenced by the amounts of stabilizers in polymerization recipes used. The particles showed variable surface areas, indicative of the presence of pores in some of the preparations and the highest surface area recorded was about 260 m2g-1. The particles were found to exhibit Langmuir-type adsorption isotherms with saturation capacity of about 9.0 and 44.2 mg/g for Na+ and Ca2+, respectively. …

Expression Of The Tobacco Β- 1,3-Glucanase Gene, Pr-2d, Following Induction Of Sar With Peronospora Tabacina, Deanna L. Funnell, Christopher B. Lawrence, Jeffrey F. Pedersen, Christopher L. Schardl

Department of Plant Pathology: Faculty Publications

Systemic acquired resistance (SAR) is induced following inoculation of Peronospora tabacina sporangia into the stems of Nicotiana tabacum plants highly susceptible to the pathogen. Previous results have shown that accumulation of acidic P-1,3-glucanases (PR-2's) following induction of SAR by P. tabacina may contribute to resistance to P. tabacina. We showed that up-regulation of the PR-2 gene, PR-2d, following stem inoculation with P. tabacina, is associated with SAR. Studies using plants transformed with GUS constructs containing the full length promoter from PR-2d or promoter deletions, provided evidence that a previously characterized regulatory element that is involved in response to …

Distance Between Pollen Donor And Recipient Influences Fruiting Success In Slickspot Peppergrass, Lepidium Papilliferum, Ian C. Robertson, Amy C. Ulappa

Biology Faculty Publications and Presentations

Plant populations are often spatially structured owing to limited dispersal of pollen and seed. Mating between neighboring individuals in such populations often leads to reduced reproductive performance relative to matings between distant individuals. This response, which may be a result of inbreeding depression or prezygotic mating barriers, was investigated for slickspot peppergrass, Lepidium papilliferum L. (Brassicaceae), a rare insect-pollinated mustard endemic to sagebrush–steppe habitat in southwestern Idaho. Through hand pollination experiments we found that individual plants receiving pollen from distant sources (75–100 m and 6.5–20 km away) had significantly higher percent fruit sets than those relying on pollen from neighboring …

Atrazine Runoff In The Blue River Basin: Geomorphology, Rainfall, And Agronomic Practices, Kundan Dhakal

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Atrazine concentrations in the Big Blue River Basin (BRB) in Nebraska and Kansas periodically exceed the U.S. EPA Maximum Contaminant Level (MCL) of 3 µg L^-1. The present study is focused on watershed variables influencing surface runoff of atrazine. The assessment includes the impact of corn and sorghum planting progress (indicating atrazine application), rainfall, antecedent soil water content, and soil restrictive layer on stream-measured weekly atrazine load in independent BRB subwatersheds for 1997 - 2004. Maximum atrazine loading occurred after most of the corn had been planted but during sorghum planting from mid-May to early June, immediately following …

Center For Grassland Studies Newsletter, Winter 2004, Volume 10, No. 1

Center for Grassland Studies: Newsletters

Matching Beef Cattle Genetics to Feed Resources by Jim Gosey, Department of Animal Science, UNL

Ecological Monitoring to Assist Producers with Grassland Production Forecasts by George Green, School of Natural Resources, UNL

Nebraska Ranch Practicum Enters Sixth Year by Jerry Volesky, Don Adams, Richard Clark, Dillon Feuz, Patrick Reece, Brent Plugge, Bud Stolzenburg and Troy Walz, UNL

Bull Riders for Biodiversity? – And Other Heresies for the Northern Great Plains by Tyler Sutton, for The Conservation Alliance of the Great Plains

2004 Nebraska Grazing Conference to be Aug. 10-11

The Nebraska Turfgrass Conference: 42 Years of Educating Nebraska Turfgrass Managers …

Compost As A Growth Substrate For Woody Ornamental Nursery Production, Jaime Crocker

Masters Theses & Specialist Projects

Peat is an expensive, environmentally nonrenewable component of media used to grow woody ornamental trees. Leaf compost from the city of Bowling Green is an inexpensive renewable resource that was substituted for peat in soil-less container media. Seeds of three commercially important tree species, Koelreuteria paniculata (goldenraintree), Quercus alba (white oak), and Magnolia grandiflora (southern magnolia) were grown in 473 mL bottomless milk containers for 150 days, then repotted to 3785 mL pots for 90 days. Media ratios were 1:0, 3:1, 1:1, 1:3, and 0:1 parts commercial media to leaf compost from the Western Kentucky University Agricultural Research Center in …

Age Dependence Of Spiral Grain In White Oaks (Quercus Alba) In Southcentral Illinois, Julia Rauchfuss

All-Inclusive List of Electronic Theses and Dissertations

Spiral grain, the alignment of wood fibers (tracheids) to the longitudinal axis of trees, is thought to be an indicator of old age and is a phenomenon that has been only studied with destructive sampling methods (cutting down trees). In this study, the usefulness of non-fatal sampling methods and existing methods to quantify spiral grain patterns in living and dead deciduous trees are examined, particularly in white oaks (Quercus alba). The overall goal is to determine if spiral grain growth is a reasonable indicator of tree age. Methods that were tested included the use of a 12 mm increment borer …

The Prairie Naturalist Volume 36, No.4 December 2004

The Prairie Naturalist

ROADSIDE BIAS IN POINT COUNT SURVEYS AT ARROWWOOD NATIONAL WILDLIFE REFUGE, NORTH DAKOTA ▪ J. S. Dieni and P. Scherr

HISTORY OF GREATER SAGE-GROUSE IN THE DAKOTAS: DISTRIBUTION AND POPULATION TRENDS ▪ . J. T. Smith, L. D. Flake, K. F. Higgins, and G. D. Kobriger

PATCH USE BY A MONOPHAGOUS HERBIVORE IN FRAGMENTED PRAIRIE LANDSCAPES ▪ . M. J. St. Pierre and S. D. Hendrix

SNOWSHOE HARE OCCURRENCE AND WINTER HABITAT ON THE MISSOURI COTEAU IN NORTH DAKOTA ▪ R. K. Murphy 243

HIGH ABUNDANCE OF NESTING LONG-EARED OWLS IN NORTH DAKOTA ▪ R. K. Murphy, L. J. Rosenfield, …

Southeast South Dakota Experiment Farm Annual Progress Report, 2004, Agricultural Experiment Station

Agricultural Experiment Station and Research Farm Annual Reports

This report contains 30 crop and livestock research and demonstration summaries of projects conducted at Southeast Research Farm in 2004. This year’s cattle report describes a project that compares feeding dried distillers grains to other oilseed supplements for wintering cows on ground corn stalks. Our crop reports show results of the many weed control projects that were conducted here as well as variety trial results and breeder evaluations for oat, corn, soybean, and forages. Several soil fertility research projects focused on strip/zone till, amending soils with gypsum, nutrient management associated with livestock manure, fertilizer placement, and other topics. Insects, soybean …