Digital Commons Network^™

Ltr Retrotransposon Evolution In Wild Sunflowers, Kaitlin Marie Stimpson

Presidential Scholars Theses (1990 – 2006)

Transposable elements are DNA sequences that are able to move from place to place in the genome, and in some cases, make copies of themselves and reinsert back into the genome. Transposable elements are divided into three classes based on their method of transposition. Class I elements transpose by an RNA intermediate, and these include L TR (long terminal repeat) and non-L TR retrotransposons. Class II elements relocate in the genome without duplication. Interestingly, class III elements entirely lack genes and rely on products of other elements for transposition. Transposable elements are no longer considered unusual or unique components of …

Contents, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Chemical Composition And Response To Dilute-Acid Pretreatment And Enzymatic Saccharification Of Alfalfa, Reed Canarygrass, And Switchgrass, Bruce S. Dien, Hans-Joachim G. Jung, Kenneth P. Vogel, Michael D. Casler, Joann F. S. Lamb, Loren Iten, Robert C. Mitchell, Gautum Sarath

Department of Agronomy and Horticulture: Faculty Publications

Alfalfa stems, reed canarygrass, and switchgrass; perennial herbaceous species that have potential as biomass energy crops in temperate regions; were evaluated for their bioconversion potential as energy crops. Each forage species was harvested at two or three maturity stages and analyzed for carbohydrates, lignin, protein, lipid, organic acids, and mineral composition. The biomass samples were also evaluated for sugar yields following pretreatment with dilute sulfuric followed by enzymatic saccharification using a commercial cellulase preparation. Total carbohydrate content of the plants varied from 518 to 655 g kg^-1 dry matter (DM) and cellulose concentration from 209 to 322 g kg …

Agronomic Evaluation And Comparison Of The Yield Of Six Multiannual Forage Species, Under Dry Land Conditions In The Ingavi Province, Freddy Óscar Paye Paye

Theses and Dissertations

The agronomical evaluation and the comparative work of six multiannual forage species was conducted in the facilities of the Benson Institute, in the community of Contorno de Letanias, Ingavi province, La Paz. The objectives were to evaluate the agronomic behavior, as well as to evaluate the dry matter (DM) yield of six multiannual forage species (grasses) under local conditions, and to determine the partial cost of production of the studied species. The annual mean temperature was 9.14°C, and 517.6 mm of precipitation. The test was conducted under the random block design test, with six different forage species, and three repetitions. …

Evaluation Of The Seed Production Of Tall Grasses Tolerant To Drought And Salinity In The Tamborada Region - Cochabamba, Magali Vallejos Arnez

Theses and Dissertations

This study was conducted on plots established by the Benson Institute in the Tamborada region of Cochabamba, Bolivia. The objective of the study was to evaluate the seed production of tall grasses that are tolerant to drought and salinity. A design of randomized blocks in divided plots with and without fertilizer was used. The results showed that the species with the greatest number of stems and inflorescence was Bromus inermis with 10.9 and 88.67 respectively. It was determined that fertilization has an effect on plant height. Furthermore, the species with the greatest seed yield was Festuca arundinacea with 30.4 kg/ha.

Sfa Gardens Newsletter, Jan 2006, Sfa Gardens, Stephen F. Austin State University

SFA Gardens Newsletters

No abstract provided.

Effect Of Fenbendazole On Turkey Semen Quality, M. R. Bakst, M. Kramer, J. Long

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

Fenbendazole (FBZ) is an anthelmintic recently approved to treat and control nematode infections in growing turkeys. When administered to growing turkeys there are no detrimental side effects. However, when we used FBZ to treat nematodes in mature breeder toms, we observed a decrease in semen quality and a subsequent precipitous decline in fertility to less than 20% within 6 wk of administration. An experiment was designed to determine the impact of FBZ administration on aspects of spermatogenesis and semen quality. We discovered that although sperm viability and concentration was not significantly affected by FBZ, this drug significantly reduced sperm mobility. …

Spermatogenesis In The Turkey (Meleagris Gallopavo): Quantitative Approach In Immature And Adult Males Subjected To Various Photoperiods, Jérôme Noirault, Jean-Pierre Brillard

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

The objectives of this study were to identify and quantitate the germ cell populations of the testes in sexually mature male turkeys (Trial 1), determine the duration of meiosis based on BrdU labeling and stereological analyses (Trial 2), and examine the impact of various photoperiods on germinal and somatic cell populations in immature and adult males (Trial 3). In Trial 1, both testes within a male had similar stereological components (P > 0.05) for all parameters analyzed. In Trial 2, the duration of Type-1 spermatocytes and round spermatids in turkeys lasted 4.5 ± 0.5 and 2.0 ± 0.5 days, respectively. In …

Separation And Identification Of Soybean Leaf Proteins By Two-Dimensional Gel Electrophoresis And Mass Spectrometry, Chenping Xu, Wesley M. Garrett, Joseph Sullivan, Thomas J. Caperna, Savithiry Natarajan

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

To establish a proteomic reference map for soybean leaves, we separated and identified leaf proteins using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Tryptic digests of 260 spots were subjected to peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS. Fifty-three of these protein spots were identified by searching NCBInr and SwissProt databases using the Mascot search engine. Sixty-seven spots that were not identified by MALDI-TOF-MS analysis were analyzed with liquid chromatography tandem mass spectrometry (LC-MS/MS), and 66 of these spots were identified by searching against the NCBInr, SwissProt and expressed sequence tag (EST) databases. …

The Best Dna Markers Pennies Can Buy A Specialized Set Of Cattle Markers For Improving Food Safety And Beef Quality, Michael P. Heaton

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

Researchers at the U.S. Meat Animal Research Center (USMARC) in Clay Center, Nebraska are developing a set of 100 DNA markers that will provide essential genetic information for improving food safety and beef quality in North American beef and dairy cattle. This powerful set of markers has been thoroughly screened to accomplish both DNA fingerprinting and parentage testing in essentially all U.S. beef and dairy populations, an ability that only a small fraction of known DNA markers have.

One key to success has been the careful sampling of U.S. beef and dairy populations to create a test panel representing the …

Impact Of Trap Design, Windbreaks, And Weather On Captures Of European Corn Borer (Lepidoptera: Crambidae) In Pheromone-Baited Traps, Thomas W. Sappington, Brendon J. Reardon, Douglas V. Sumerford

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

Pheromone-baited traps are often used in ecological studies of the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae). However, differences in trap captures may be confounded by trap design, trap location relative to a windbreak, and changes in local weather. The objectives of this experiment were, first, to examine differences in O. nubilalis adult (moth) captures among the Intercept wing trap, the Intercept bucket/funnel UNI trap, and the Hartstack wire-mesh, 75-cm-diameter cone trap (large metal cone trap) as well as among three cone trap designs. Second, we examined the influence of the location of the large metal cone trap relative …

Usmarc Beef Carcass Instrument Grading Systems, Tommy Wheeler, Steven Shackelford, Mohammad Koohmaraie

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

Evaluation of Beef Carcass Grades with Image Analysis

Beef Tenderness

Post-Weaning Performance Of Steers From Varying Calving And Weaning Strategies In Montana, E. E. Grings, W. A. Phillips, R. E. Short, H. Mayeux, R. K. Heitschmidt

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

The impact of varied calving and weaning times on post-weaning production of steer calves was evaluated in a 3- yr study. Steers (approximately 12 steers per calving-weaning treatment per year) born in late winter or early spring were weaned at 190 or 240 d of age, and steers born in late spring were weaned at 140 or 190 d of age after grazing with their dams on native range. Steers were pen-fed a growing diet until approximately 375 kg BW. They were then moved to an individual feeding facility and fed a higher-energy diet. Steers were allotted to harvest dates …

Host Specificity Of Divergent Populations Of The Leaf Beetle Diorhabda Elongata (Coleoptera: Chrysomelidae), A Biological Control Agent Of Saltcedar (Tamarix Spp.), Lindsey R. Milbrath, C. Clark Deloach

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

The leaf beetle, Diorhabda elongata (Brullé) sensu lato, was released in 2001 for the classical biological control of exotic saltcedars, a complex of invasive Tamarix species and hybrids. It did not establish at sites south of 37°N latitude where summer daylengths are below the critical photoperiod of the northern-adapted populations of the beetle that were released. Therefore, we assessed the host specificity of four D. elongata populations collected from more southern latitudes in the Old World (Tunisia, Crete, Uzbekistan, and Turpan, China). All populations were similar to each other and the previously released populations of D. elongata in their …

Effect Of Chemical Fertilization And Organic Amaranth (Amaranthus Caudatus L.) Var. Alegria Iniap Chaltura, Andrade Andrade Pablo Raúl

Theses and Dissertations

The present investigation was made in the Experimental Farm "La Pradera", located in the province of Imbabura, the parish of San José de Chaltura, to 1350 meters above sea level and an average temperature of 16, 4⁰ C. To analyze the effect of the chemical and organic fertilization in amaranth of variety INIAP "Alegría" was the primary target of the investigation. The field work was made in a lapse of 6 months. The design of complete blocks (DBCA) with 15 treatments was used at random and three repetitions by treatment. The experimental unit was 18 m². It was evaluated by …

Nematodes In Western Australian Vineyards, Vivien Vanstone, Neil Lantzke

Bulletins 4000 -

Nematodes are worm-like microscopic animals that live in the soil. There are numerous soil-inhabiting nematode species, but not all are harmful to plants. Some nematodes are plant-parasitic, feeding on and damaging roots, including those of grapevine. Feeding activities of these nematodes reduce the vine’s ability to take up water and nutrients from the soil, leading to lack of vigour, symptoms of nutrient deficiency, wilting, lower yield, vine decline and, in severe cases, vine death. Nematode feeding sites can also lead to entry of other disease-causing organisms (e.g. fungi or bacteria), resulting in rapid vine decline.

Nematodes can survive in the …

Slow Ligand Binding Kinetics Dominate Ferrous Hexacoordinate Hemoglobin Reactivities And Reveal Differences Between Plants And Other Species, Benoit J. Smagghe, Gautam Sarath, Emily Ross, Jean-Louis Hilbert, Mark S. Hargrove

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

Hexacoordinate hemoglobins are found in many living organisms ranging from prokaryotes to plants and animals. They are named “hexacoordinate” because of reversible coordination of the heme iron by a histidine side chain located in the heme pocket. This endogenous coordination competes with exogenous ligand binding and causes multiphasic relaxation time courses following rapid mixing or flash photolysis experiments. Previous rapid mixing studies have assumed a steady-state relationship between hexacoordination and exogenous ligand binding that does not correlate with observed time courses for binding. Here, we demonstrate that this assumption is not valid for some hexacoordinate hemoglobins, and that multiphasic time …

Sentinel Nematodes Of Land-Use Change And Restoration In Tallgrass Prairie, T. C. Todd, T. O. Powers, P.G. Mullin

Department of Plant Pathology: Faculty Publications

Changes in land use and the associated changes in land cover are recognized as the most important component of human-induced global change. Much attention has been focused on deforestation, but grasslands are among the most endangered ecosystems on Earth. The North American tallgrass prairie is a dramatic example, exhibiting a greater than 95% decline in historical area. Renewed interest in prairie conservation and restoration has highlighted the need for ecological indicators of disturbance and recovery in native systems, including the below ground component. The tallgrass prairie differs from the agricultural systems that have replaced it in having greater diversity and …

A Position Paper On The Electronic Publication Of Nematode Taxonomic Manuscripts, Eyualem Abebe, James G. Baldwin, Byron Adams, Duane Hope, Scott Gardner, Robin Huettel, Peter Mullin, Thomas O. Powers, Jyotsna Sharma, Weimin Ye, William K. Thomas

Department of Plant Pathology: Faculty Publications

Several nematode species have now attained ‘model organism’ status, yet there remain many niches in basic biological inquiry for which nematodes would be ideal model systems of study. However, furthering the model system approach is hindered by lack of information on nematode biodiversity. The shortage of taxonomic resources to inventory and characterize biodiversity hinders research programs in invasion biology, ecosystem functioning, conservation biology, and many others. The disproportion between numbers of species to be described and numbers of available taxonomic specialists is greater for Nematoda than for any other metazoan phylum. A partial solution to the taxonomic impediment is the …

Regulation Of Hyphal Morphogenesis And The Dna Damage Response By The Aspergillus Nidulans Atm Homolog Atma, Iran Malavazi, Camile P. Semighini, Marcia Regina Von Zeska Kress, Steven D. Harris, Gustavo H. Goldman

Department of Plant Pathology: Faculty Publications

Ataxia telangiectasia (A-T) is an inherited disorder characterized by progressive loss of motor function and susceptibility to cancer. The most prominent clinical feature observed in A-T patients is the degeneration of Purkinje motor neurons. Numerous studies have emphasized the role of the affected gene product, ATM, in the regulation of the DNA damage response. However, in Purkinje cells, the bulk of ATM localizes to the cytoplasm and may play a role in vesicle trafficking. The nature of this function, and its involvement in the pathology underlying A-T, remain unknown. Here we characterize the homolog of ATM (AtmA) in the filamentous …

Anthropogenic Drivers Of Ecosystem Change: An Overview, Gerald C. Nelson, Elena Bennett, Asmeret A. Berhe, Kenneth G. Cassman, Ruth Defries, Thomas Dietz, Achim R. Dobermann, Andrew Dobson, Anthony Janetos, Marc Levy, Diana Marco, Nebojsa Nakicenovic, Brian O'Neill, Richard Norgaard, Gerhard Petschel-Held, Dennis Ojima, Prabhu Pingali, Robert Watson, Monika Zurek

Department of Agronomy and Horticulture: Faculty Publications

This paper provides an overview of what the Millennium Ecosystem Assessment (MA) calls “indirect and direct drivers” of change in ecosystem services at a global level. The MA definition of a driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely by altering one or more direct drivers. Global driving forces are categorized as demographic, economic, sociopolitical, cultural and religious, scientific and technological, and physical and biological. Drivers in all categories other than physical and biological are considered indirect. Important …

Developing And Extending Sustainable Agriculture: A New Social Contract, Michele Schoeneberger, Gary Bentrup, Charles A. Francis, Richard Straight

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Conclusions

Based on the practical community applications of woody buffe rs and multifuncti onal areas that grew from the ini tial concepts ofecobelts. we are convinced that this type of initiative is a viable option in establishing a positive interface between different types of human activities. The challenge becomes more real every day, as cities expand and both city-edge subdivisions and acreages create ever more interfaces between people with different and often con!1icting activities and basic values. There is a need to provide some logical and acceptable boundary between these people and their different lifestyles. It is also desirable to …

Estrogenic Activity In The Environment: Municipal Wastewater Effluent, River, Ponds, And Wetlands, Nancy W. Shappell

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

Estrogenic activity of regional water samples was evaluated. Samples obtained from wetlands and ponds involved in various agricultural land uses, from three river sites over four seasons, and from municipal wastewater effluent held in storage lagoons were evaluated. The estrogen- responsive cell line MCF-7 BOS was used in the E-screen assay to determine 17β-estradiol equivalents (E₂ Eq) of water samples extracted by solid-phase extraction. Estrogenic activity in surrounding wetlands and ponds from different land uses was not different, with 10^-12 M E2 Eq (0.3 ppt). Estrogenic activity of Red River samples was within the same range as wetland–pond …

Un-Ionized Ammonia Exposure In Nile Tilapia: Toxicity, Stress Response, And Susceptibility To Streptococcus Agalactiae, Joyce J. Evans, David J. Park, Gregg C. Brill, Phillip H. Klesius

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

A series of experiments were conducted to determine the toxicity, behavior, blood glucose stress response, and disease susceptibility in Nile tilapia Oreochromis niloticus following un-ionized ammonia (UIA) exposure. The acute toxicity of un-ionized ammonia to Nile tilapia was measured in a 96-h static test. The median lethal concentration (LC50) was 1.46 mg/L UIA at 24 and 48 h postexposure, 1.33 mg/ L at 72 h postexposure, and 0.98 mg/L at 96 h postexposure. No mortalities were noted in unexposed (0 mg/ L) control fish or fish exposed to 0.5 mg/L UIA. However, 93–100% mortalities were observed within 24 h among …

International Shipping Of Fumonisins From Maize Extracts On C18 Sorbent, R. T. Riley, O. A. Torres, E. Palencia

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

Fumonisins are mycotoxins found in maize. In developing countries, the resources required for analysis are often lacking, and the shipping of maize between countries can be difficult since the importation of plant materials requires permits/ inspection to prevent the entry of pests that frequently infest maize. A simple, safe and legal method for shipping maize extracts to the USA was needed to conduct a survey of fumonisins in Central America. The objective was to develop a method for isolating and shipping maize extracts for fumonisin analysis so as to facilitate a survey of fumonisin exposure. The results indicate that fumonisins …

Improvements In Channel Catfish Growth After Two Generations Of Selection And Comparison Of Performance Traits Among Channel Catfish, Blue Catfish, And Hybrid Catfish Fingerlings In An Aquarium Rack System, Brian C. Small

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

A 9-week growth study was conducted to compare the fingerling performance of two genetic groups of channel catfish Ictalurus punctatus (United States Department of Agriculture [USDA] 103 and USDA303) with that of blue catfish I. furcatus and their hybrid in an aquarium rack system. Fish of approximately 20 g were randomly selected from multifamily populations and acclimated to the aquarium rack system for 2 weeks prior to the start of the 9-week study. Differences in growth indices, feed and protein efficiency, nitrogen retention, whole-body proximate composition, and plasma cortisol levels were determined at the completion of the study. The USDA303 …

Restoration Of Spermatogenesis And Male Fertility By Transplantation Of Dispersed Testicular Cells In The Chicken, Pavel Trefil, Alena Micáková, Jitka Mucksová, Jiń Hejnar, Martin Poplstein, Murray R. Bakst, Jirí Kalina, Jean-Pierre Brillard

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

Transplantation of male germ cells into sterilized recipients has been widely used in mammals for conventional breeding and transgenesis purposes. This study presents a workable approach for germ cell transplantation between male chickens. Testicular cells from adult and prepubertal donors were dispersed and transplanted by injection directly into the testes of recipient males sterilized by repeated gamma irradiation. We describe the repopulation of the recipient seminiferous epithelium up to the production of heterologous sperm in about 50% of transplanted males. In comparison to males transplanted with testicular cell preparations from adult donors, in which the first ejaculates with sperm were …

Human Emanations And Related Natural Compounds That Inhibit Mosquito Host-Finding Abilities, Ulrich R. Bernier, Daniel Kline, Kenneth H. Posey

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

One mechanism by which the action of semiochemicals can be classified is based on the behavioral impact within or external to the species of interest. As such, one can classify a chemical as one of the following^2,3:

1. Pheromone, if it results in response between insects of the same species
2. Kairomone, if it results in response in another species that benefits the species receiving the chemical cue
3. Allomone, if it results in response in another species that benefits the species releasing the chemical cue

However, the distinctions can be more specific by classification of chemical cues …

Laboratory Evaluation Of Avian Odors For Mosquito (Diptera: Culicidae) Attraction, S. A. Allan, Ulrich R. Bernier, D. L. Kline

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

Attraction of Culex quinquefasciatus Say, Culex tarsalis Coquillett, Culex nigripalpus Theobald, and Aedes aegypti (L.) to avian and other host odors was investigated in a dual-port olfactometer. Although attraction to a human arm was high for Ae. aegypti (>80%) and low for all Culex spp. (<25%), all species responded similarly to a chicken (55.3-73.6%). Responses of Ae. aegypti, Cx. quinquefasciatus, and Cx. nigripalpus to feathers were low (<20%) but greater than to controls. There was no difference in attraction of Cx. tarsalis to feathers or controls. Responses to CO₂ (5 ml/min) were low for all species (<15%) except Cx. tarsalis, which were moderate (24.5%). When feathers were combined with CO2, the resulting attraction was additive or lower than responses …

The Effects Of Light Reduction Treatments On Mobile Epifaunain An Amphibolis Griffithii (Black) Den Hartog Seagrass Ecosystem, Helen Barwick

Theses : Honours

One of the main anthropogenic disturbances to seagrass meadows in Australia is reduction in light availability, through nutrient enrichment or suspended sediments. Dredging can create suspended sediment plumes from the expulsion of particulates into the water column and in tum reduces light penetration to seagrass ecosystems. Preliminary investigations have demonstrated that light reduction for different intensities and durations results in reduced seagrass and epiphytic algae biomass. The main aim of this study was to determine the effects of different intensities and durations of light reduction on epifaunal assemblages in Amphibolis griffithii seagrass meadows in Jurien Bay, Western Australia. This was …