Life Sciences Commons^™

Two Large-Insert Soybean Genomic Libraries Constructed In A Binary Vector: Applications In Chromosome Walking And Genome Wide Physical Mapping, K. Meksem, K. Zobrist, E. Ruben, D. L. Hyten, T. Quanzhou, H-B. Zhang, D. A. Lightfoot

Department of Agronomy and Horticulture: Faculty Publications

Large DNA insert libraries in binary T-DNA vectors can assist in the isolation of the gene(s) under-lying a quantitative trait locus (QTL). Binary vectors facilitate the transfer of large-insert DNA fragments containing a QTL from E. coli to Agrobacterium sp. and then to plants. We constructed two soybean large-insert libraries from cv. Forrest in the pCLD04541 (V41) binary vector after partial digestion of genomic high-molecular-weight DNA with BamHI or HindIII. The libraries contain 76,800 clones with an average insert size of 125 kb, and therefore represent 9.5-fold haploid genome equivalents. Colony hybridization using a chloroplast-specific probe infers that …

Cattle Lack Vascular Receptors For Escherichia Coli O157:H7 Shiga Toxins, Ingrid M. Pruimboom-Brees, Tim W. Morgan, Mark R. Ackermann, Evelyn A. Dean-Nystrom, James E. Samuel, Nancy A. Cornick, Harley W. Moon

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

Escherichia coli O157:H7 causes Shiga toxin (Stx)-mediated vascular damage, resulting in hemorrhagic colitis and the hemolytic uremic syndrome in humans. These infections are often food-borne, and healthy carrier cattle are a major reservoir of E. coli O157:H7. We were interested in knowing why cattle are tolerant to infection with E. coli O157:H7. Cattle tissues were examined for the Stx receptor globotriaosylceramide (Gb₃), for receptivity to Stx binding in vitro, and for susceptibility to the enterotoxic effects of Stx in vivo. TLC was used to detect Gb3 in tissues from a newborn calf. Gb₃ was detected …

Murine Monoclonal Antibodies Specific For Lipopolysaccharide Of Escherichia Coli O26 And O111, Mildred Rivera-Betancourt, James E. Keen

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

Monoclonal antibody (MAb) 12F5 reacted with 35 Escherichia coli O26 isolates and cross-reacted with 1 of 365 non-E. coli O26 isolates. MAb 15C4 reacted with 30 E. coli O111 strains and 8 Salmonella O35 strains (possessing identical O antigen) but not with 362 other bacterial strains. Lipopolysaccharide immunoblots confirmed MAb O-antigen specificity.

Before You Say Yes: A Planning Guide For Speakers, Charles A. Francis, Heidi Carter, Cris Carusi, James W. King

Department of Agronomy and Horticulture: Faculty Publications

We need guidelines to help us decide whether to accept invitations to speak, whether to a class on campus or a special interest group outside. As educators and workshop organizers, we could also use suggestions on how to approach potential speakers. This article describes a single-page format that can be used to guide the planning process. Essential elements include contact information, location and organization of the activity, audience, learning goals, expected content, conclusions, and evaluation. Use of this planning sheet can give organization to an often haphazard process of planning, and enhance the potential of achieving the learning goals of …

Comparison Of Three Leaf Area Index Meters In A Corn Canopy, Wally Wilhelm, K. Ruwe, Michael R. Schlemmer

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

Measurement of leaf area index (LAI) is critical to understanding many aspects of crop development, growth, and management. Avail- ability of portable meters to estimate LAI non-destructively has greatly increased our ability to determine this parameter during the cropping season. However, with several devices on the market, each with an independent set of protocols for gathering accurate estimates of LAI, it is necessary for scientists to have comparisons of these meters under field conditions before selecting one for purchase and use. The objective of our study was to compare the LAI estimates by three meters (AccuPAR, LAI-2000, and SunScan) to …

Simulating Inbred-Maize Yields With Ceres-Im, Daniel P. Rasse, Joe T. Ritchie, Wally Wilhelm, Jun Wei, Edward C. Martin

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

CERES-Maize, which was designed for simulation of hybrid maize (Zea mays L.), cannot be applied directly to seed-producing inbred maize because of specific field operations and physiological traits of inbred maize plants. We developed CERES-IM, a modified version of CERES-Maize 3.0 that accommodates these inbred-specific operations and traits, using a set of phenological measurements conducted in Nebraska (NE), and further tested this model with a set of field data from Michigan (MI). Detasseling (i.e., removal of the tassels from the female plants) was conducted prior to silking. Male rows were removed approximately 10 d following 75% silking. The thermal …

Evaluation Of Stomoxys Calcitrans (Diptera: Muscidae) Behavioral Response To Human And Related Odors In A Triple Cage Olfactometer With Insect Traps, Raul A. Alzogaray, David A. Carlson

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

A triple cage olfactometer provided with insect traps was used for evaluating behavioral responses of Stomoxys calcitrans (L.) females to human skin and breath, CO₂, and L-lactic acid analogs. After demonstrating there were no significant differences caused by cage location or time of day, 3 sets of 3 olfactometer tests were performed in a day, every 2 h beginning at 0900 hours. When a human hand was used as attractant, the attraction (expressed as percentage of trapped flies) increased as a function of the time; an inverted U-shaped relationship between attractancy and air speed was observed; and variation …

Effects Of Acid Adaptation Of Escherichia Coli O157:H7 On Efficacy Of Acetic Acid Spray Washes To Decontaminate Beef Carcass Tissue, Elaine Berry, Catherine N. Cutter

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

Exposure to low pH and organic acids in the bovine gastrointestinal tract may result in the induced acid resistance of E. coli O157:H7 and other pathogens that may subsequently contaminate beef carcasses. The effect of acid adaptation of E. coliO157:H7 on the ability of acetic acid spray washing to reduce populations of this organism on beef carcass tissue was examined. Stationary-phase acid resistance and the ability to induce acid tolerance were determined for a collection of E. coliO157:H7 strains by testing the survival of acid-adapted and unadapted cells in HCl-acidified tryptic soy broth (pH 2.5). ThreeE. coli …

Escherichia Coli O157:H7 Causes More-Severe Systemic Disease In Suckling Piglets Than In Colostrum-Deprived Neonatal Piglets, Evelyn A. Dean-Nystrom, Joachim F. L. Pohlenz, Harley W. Moon, Alison D. O’Brien

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

Our objective was to determine if suckling neonatal piglets are susceptible to enterohemorrhagic Escherichia coli (EHEC) O157:H7 disease. Surprisingly, EHEC O157:H7 caused more-rapid and more-severe neurological disease in suckling neonates than in those fed an artificial diet. Shiga toxin-negative O157:H7 did not cause neurological disease but colonized and caused attaching-and-effacing intestinal lesions.

Intsormil 2000 Annual Report, John M. Yohe, Thomas Crawford, Jr., Joan Frederick, Dorothy Stoner

INTSORMIL Impacts and Bulletins

Presently, worldwide, more than 800 million people are hungry and over I billion are desperately poor, and food demand is increasing rapidly. The majority of poor live in rural areas in developing countries and agricultural and food systems development is vital to economic growth; improving environmental quality; strengthening nutrition, health and child survival; improving the status of women; and promoting democratization. It is estimated that by 2000, the number of people living in developing countries will grow from 4.9 billion to 6.8 billion people. More than 1.3 billion people today live on less than one dollar per day. It is …

Effect Of Vacuum On The Performance Of The Flame Ionization Detector Used For Vacuum-Outlet Gas Chromatography, Ulrich R. Bernier, Christopher L. Bray, Richard A. Yost

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

Vacuum-outlet operation of short fused-silica open tubular columns for gas chromatography provides benefits to analysis speed by increasing the optimum velocity while minimizing the loss in resolution. Vacuum-outlet operation of a column with a gas chromatographic detector necessitates that the detector also be under vacuum. Simple modifications were made to a gas chromatograph-flame ionization detector (GC-FID) for vacuum-inlet and vacuum-outlet operation. The vacuum-inlet system was operated in the splitless mode to allow for efficient sample loading prior to operation at reduced pressures. The goal of FID operation at 100 torr or less was achieved by using oxygen in place of …

Physiology And Reproduction: Plasma 17Β-Estradiol Levels And Ovarian Interstitial Cell Structure In Embryonic Japanese Quail, M. A. Abdelnabi, M. R. Bakst, J. E. Woods, M. A. Ottinger

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

Plasma concentrations of 17β-estradiol (E₂) and left ovarian histology were investigated by light and electron microscopy in female Japanese quail from Day 10 of embryonic development through Day 7, posthatch. Plasma E₂ levels remained relatively constant (102 to 140 pg/mL) in the embryo followed by a sharp decrease posthatch (47 to 70 pg/mL).

Beginning on Day 10 of incubation, cells in the medullary portion (medullary cell; MC) of the left ovaries exhibited ultrastructural evidence of steroidogenic capability. The MC had numerous lipid droplets in close proximity to the smooth endoplasmic reticulum (SER). Mitochondria were also …

Similarity And Divergence Among Viruses In The Genus Furovirus, Yukio Shirako, Nobuhiro Suzuki, Roy C. French

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

Nucleotide sequences of RNAs 1 and 2 of a Japanese strain of soil-borne wheat mosaic virus (SBWMV), the type species of the genus Furovirus, and sorghum chlorotic spot virus (SCSV) were determined from cloned cDNA. The relationship among the Japanese and US strains of SBWMV, SCSV, oat golden stripe virus (OGSV), and recently proposed Chinese wheat mosaic and European wheat mosaic viruses (CWMV and EWMV) were examined at the nucleotide and amino acid levels. Pairwise comparisons of genome-encoded proteins among the six viruses showed that the US strains of SBWMV and CWMV were the most closely related pair in RNA …

Oxygen Metabolism In Plantlbacteria Interactions: Characterization Of The Oxygen Uptake Response Of Plant Suspension Cells, C. Jacyn Baker, E. W. Orlandi, Kenneth L. Deahl

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

In recent years the accumulation of reactive oxygen species (ROS) has been studied in plant cell suspension systems treated with bacterial pathogens. However, the associated utilization of molecular oxygen has not been well characterized. Using a multi-electrode oxygen analyser, the rates of oxygen consumption by tobacco cells during bacterial interactions were monitored. Heat-killed (HK) bacteria, which initiate an immediate ROS response in plant cells, were used as an elicitor to avoid complications of oxygen consumption by viable bacteria. An increase in oxygen uptake by the tobacco cells occurred within 4 min after addition of HK-bacteria and lasted for about 10 …

Inhibition Of Cysteine And Aspartyl Proteinases In The Alfalfa Weevil Midgut With Biochemical And Plant-Derived Proteinase Inhibitors, Stephen E. Wilhite, Thomas C. Elden, Joze Brzin, Ann C. Smigocki

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

Proteolytic activities in alfalfa weevil (Hypera postica) larval midguts have been characterized. Effects of pH, thiol activators, low-molecular weight inhibitors, and proteinase inhibitors (PIs) on general substrate hydrolysis by midgut extracts were determined. Hemoglobinolytic activity was highest in the acidic to mildly acidic pH range, but was maximal at pH 3.5. Addition of thiolactivators dithiothreitol (DTT), 2-mercaptoethanol (2-ME), or l-cysteine had little effect on hemoglobin hydrolysis at pH 3.5, but enhanced azocaseinolytic activity two to three-fold at pH 5.0. The broad cysteine PI E-64 reduced azocaseinolytic activity by 64% or 42% at pH 5 in the presence or …

Behavioral Response Of Stomoxys Calcitrans (Diptera: Muscidae) To Conspecific Feces And Feces Extracts, David Carlson, Raul Alzogaray, Jerome Hogsette

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

The attraction response of Stomoxys calcitrans (L.) to its own feces was evaluated in a triple cage olfactometer. Both time- and concentration-response relationships were obtained for female S. calcitrans exposed to cellulose sponges impregnated with fresh fly feces or filter papers treated with chloroform: methanol extracts of fresh fly feces in 6-min tests. Attraction to feces collected on cellulose sponges decreased as the air flow increased. Feces collected on cellulose sponges and held for 28-31 d retained attractive activity. More female flies were attracted than males to feces on sponges or to polar solvent extracts of feces-contaminated cages. The activity …

Design And Application Of A Polyclonal Peptide Antiserum For The Universal Detection Of Leptin Protein, Mark P. Richards, Thomas J. Caperna, Theodore H. Elasser, Christopher M. Ashwell, John P. Mcmurtry

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

An epitope-specific polyclonal antiserum was produced in rabbits immunized against a synthetic 15 amino acid peptide (QRVTGLDFIPGLHPV) derived from the coding sequence reported for the porcine leptin gene (GenBank Accession No. U59894). This peptide contains a core sequence comprised of eight amino acids (GLDFIPGL) that is totally conserved in all leptin proteins studied to date. Purified recombinant human, mouse, rat, pig, and chicken leptin proteins were separated by polyacrylamide gel electrophoresis (SDS-PAGE) and electro-blotted onto PVDF membranes. Western blots were developed employing the leptin-specific peptide antiserum with an alkaline-phosphatase-conjugated anti-rabbit IgG second antibody chromogenic system. The peptide antiserum was found …

Bovine Blastocyst-Derived Trophectoderm And Endoderm Cell Cultures: Interferon Tau And Transferrin Expression As Respective In Vitro Markers, Neil C. Talbot, Thomas J. Caperna, J. Lannett Edwards, Wes Garrett, Kevin D. Wells, Alan D. Ealy

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

Continuous cultures of bovine trophectoderm (CT-1 and CT- 5) and bovine endoderm (CE-1 and CE-2) were initiated and maintained on STO feeder cells. CT-1 and CT-5 were derived from the culture of intact, 10- to 11-day in vitro-produced blastocysts. CE-1 and CE-2 were derived from the culture of immunodissected inner cell masses of 7- to 8-day in vitro-produced blastocysts. The cultures were routinely passaged by physical dissociation. Although morphologically distinct, the trophectoderm and endoderm both grew as cell sheets of polarized epithelium (dome formations) composed of approximately cuboidal cells. Both cell types, particularly the endoderm, grew on top …

Variation In Boll Weevil (Coleoptera: Curculionidae) Captures In Pheromone Traps Arising From Wind Speed Moderation By Brush Lines, Thomas W. Sappington, Dale W. Spurgeon

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

Paired trap lines of Þve boll weevil pheromone traps each were placed on opposite sides of a brush line at six different sites on a plantation in the Lower Rio Grande Valley of Texas. Temperature, wind speed, and wind direction were monitored with a nearby weather station. We observed a strong negative relationship between mean daily wind speed and total daily capture of boll weevils. About half of the day-to-day variation in weevil captures was explained by wind speed alone. In addition, our data indicate that much of the variation between traps within days may arise from differences in local …

Feeding Fitness And Quality Of Domesticated And Feral Predators: Effects Of Long-Term Rearing On Artificial Diet, Allen Carson Cohen

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

Predatory geocorids, Geocoris punctipes Say (Geocoridae: Hemiptera), that had been reared (domesticated) for over 6 years (60 continuous generations) on an artificial diet were compared with feral (F1) counterparts to determine possible domestication-associated losses in predatory capabilities. Using adult female predators provided with either tobacco budworm larvae, Heliothis uirescens F., or pea aphids, Acyrthosiphon pisum Harris, as prey, I measured predator weights, handling time with a single prey, amount extracted, consumption rate, and feeding (gut) capacity. Domesticated females were significantly smaller than ferals, weighing 4.53 mg versus 5.09 mg, respectively. Domestication did not significantly influence handling times, which averaged 131 …

Kernel Morphology Variation In A Population Derived From A Soft By Hard Wheat Cross And Associations With End-Use Quality Traits, Christine J. Bergman, Daisy G. Gualberto, Kimberly A. Garland-Campbell, Mark E. Sorrells, Patrick L. Finney

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

Physical attributes, including kernel morphology, are used to grade wheat, and indicate wheat milling and baking quality (MBQ). Using a recombinant inbred population derived from a soft by hard wheat cross, this study quantified kernel traits' sources of variation, studied their heritability, and relationships between morphological and MBQ traits. Transgressive segregation occurred for all traits. Thousand-kernel weight (TKW) and kernel texture (NIR-T) were primarily influenced by genotype and test weight (TW) mainly by year. NIR-T had the highest heritability. Low genetic correlation (GCOR) between kernel length (LEN) and width WID) suggest independent inheritance. NIR-T and LEN, or WID, showed low …

Elongated Chambers For Field Studies Across Atmospheric Co2 Gradients, H. B. Johnson, H. W. Polley, R. P. Whitis

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

We describe a field facility that controls CO₂ along continuous gradients from superambient to subambient concentrations. The facility consists of two transparent, tunnel-shaped chambers, each 1-m wide and tall and 60-m long. Pure CO₂ is injected into one chamber during daylight to initiate a superambient CO₂ gradient (550–350 µmol mol^–1). Ambient air is introduced to the second chamber to initiate a subambient CO₂ gradient (350–200 µmol mol^–1). CO₂ concentrations at night are regulated at 150 µmol mol^–1 above daytime values along each gradient. The CO₂ gradients are maintained by …

Analysis Of Human Skin Emanations By Gas Chromatography/Mass Spectrometry. 2. Identification Of Volatile Compounds That Are Candidate Attractants For The Yellow Fever Mosquito (Aedes Aegypti), Ulrich R. Bernier, Daniel L. Kline, Donald Barnard, Carl Schreck, Richard A. Yost

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

Volatile compounds emanated from human skin were studied by gas chromatography/mass spectrometry (GC/ MS). The purpose of this study was to identify compounds that may be human-produced kairomones which are used for host location by the mosquito, Aedes aegypti (L.). The procedure used to collect volatiles was chosen because of prior knowledge that attractive substances can be transferred from skin to glass by handling. Laboratory bioassays have shown that the residuum on the glass remains attractive to mosquitoes until the compounds of importance evaporate. The sampling and analytical procedures modeled the above-cited process as closely as possible except that the …

Scavenging Of H2O2 And Production Of Oxygen By Horseradish Peroxidas, C. Jacyn Baker, Kenneth Deahl, John Domek, Elizabeth W. Orlandi

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

Peroxidases catalyze many reactions, the most common being the utilization of H₂O₂ to oxidize numerous substrates (peroxidative mode). Peroxidases have also been proposed to produce H₂O₂ via utilization of NAD(P)H, thus providing oxidant either for the first step of lignification or for the "oxidative burst" associated with plant-pathogen interactions. The current study with horseradish peroxidase characterizes a third type of peroxidase activity that mimics the action of catalase; molecular oxygen is produced at the expense of H₂O₂ in the absence of other reactants. The oxygen production and H₂O_{2 …}

Crop Quality And Utilization: A Twelve-Hour In Vitro Procedure For Sorghum Grain Feed Quality Assessment, Jeffrey F. Pedersen, Todd Milton, R. A. Mass

Department of Agronomy and Horticulture: Faculty Publications

Improvedmethods for assessing cereal crop feed value are a prerequisite for the genetic improvement of sorghum [Sorghum bicolor (L.) Moench] feed value. Rate of starch digestion is now commonly believed to be the limiting factor in sorghum utilization by cattle (Bos taurus). However, techniques to assess this trait are not useful to sorghum breeders because of high labor inputs, lab error associated with starch measurement, and need for high numbers of replications. The objective of this study was to develop a simple technique capable of identifying differences in digestion between sorghum and corn (Zea mays L.) …

Yields And Nitrogen Dynamics In A Rice–Wheat System Using Green Manure And Inorganic Fertilizer, Milkha S. Aulakh, Tejinder S. Khera, John W. Doran, Kuldip Singh, Bijay Singh

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

Integrating fertilizer N (FN) with legume green manures (GM) can foster sustainable and environmentally sound agricultural systems in subtropical, semiarid soils low in organic matter. A 4-yr replicated field experiment with irrigated rice (Oryza sativa L.) and wheat (Triticum aestivum L.) rotations was conducted on a sandy loam soil in the Punjab of India to evaluate the effects of incorporating cowpea (Vigna unguiculata L.) or sesbania (Sesbania aculeata L.) GM on crop productivity, N-use efficiency, and NO₃ leaching. Rice grain yields with pretransplant incorporation of 20 and 40 Mg GM ha^-1 (GM₂₀ and …

Ethylene Production, Cluster Root Formation, And Localization Of Iron(Iii) Reducing Capacity In Fe Deficient Squash Roots, Brian M. Waters, Dale G. Blevins

Department of Agronomy and Horticulture: Faculty Publications

Dicots and non-graminaceous monocots have the ability to increase root iron(III) reducing capacity in response to iron (Fe) deficiency stress. In squash (Cucurbita pepo L.) seedlings, Fe(III) reducing capacity was quantified during early vegetative growth. When plants were grown in Fe-free solution, the Fe(III) reducing capacity was greatly elevated, reached peak activity on day 4, then declined through day 6. Root ethylene production exhibited a temporal pattern that closely matched that of Fe(III) reducing capacity through day 6. On the 7th day of Fe deficiency, cluster root morphology developed, which coincided with a sharp increase in the root Fe(III) …