Digital Commons Network^™

Fractional Composition Of Grain Sorghum (Sorghum Bicolor) After Wet-Peeling In A Centrifugal Pump, K. R. Lochte-Watson, Curtis L. Weller, Kent M. Eskridge

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Use of a centrifugal pump to peel and facilitate separation of grain sorghum kernels into three fractions was investigated. Special emphasis was given to separating fractions to achieve a high concentration of wax in one fraction and a high concentration of starch in another. Trials were conducted to determine the effects of both soak time and recirculation time on wet-peeling. After peeling, three fractions, peeled kernel, bran, and suspended solids, were collected. Together, the bran and suspended solids fractions contained 12.7% of the initial total dry solids, 90% of initial wax, and 8.1% of the initial starch. Peeled kernel fraction …

Narrow Grass Hedge Effects On Phosphorus And Nitrogen In Runoff Following Manure And Fertilizer Application, B. Eghball, John E. Gilley, L. A. Kramer, T. B. Moorman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff losses of nitrogen (N) and phosphorus (P) from field applied manure can contribute to surface water pollution. Grass hedges may reduce runoff losses of nutrients and sediment. The objective of this study was to evaluate the effects of narrow switchgrass (,i>Panicum virgatum L.) hedges (~0.75 m wide) on the transport of P and N from a field receiving beef cattle feedlot manure under tilled and n-till conditions. This study was conducted on a steep (12% average slope) Monona silt loam (fine-silty, mixed, superactive, mesic Typic Hapludolls) soil near Treynor, Iowa. The experiment was a split-plot with no-till and …

Performance Tests Of Three-Point Mounted Implement Guidance Systems: Ii. Results, Michael F. Kocher, Michael B. Smith, Robert D. Grisso, Linda J. Young

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Side-shift and disk-steer implement guidance systems were tested for differences in performance during cultivation on fields with 0 and 5% side slope. Test speeds were slow (4.8 km/h, 3 mph) and medium (8.0 km/h, 5 mph). Test path shapes included a tractor ramp, implement ramp, sine and curve. Performance measures included tractor positional error, implement positional error, torque from side forces on the cultivator non-swiveling coulters, and travel speed. Relatively few significant differences between guidance systems were detected, and most of those involved interaction with path shape. Therefore, no clear conclusion could be reached indicating one guidance system was better …

Performance Tests Of Three-Point Mounted Implement Guidance Systems: I. Procedure, Michael F. Kocher, Michael B. Smith, Robert D. Grisso, Leonard L. Bashford

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A procedure is presented for determining the performance of three-point mounted implement guidance systems. A test track with tractor ramp, implement ramp, sine wave, and curve path shapes was used as the desired path to guide the tractor and implement, and as a reference location for measuring implement positional errors. Potentiometers were used with mechanical frames to measure the tractor and implement positional errors (lateral displacement between the intended and actual travel paths). An optoelectronic sensor triggered acquisition of data from all sensors at known locations [15.2 cm (6 in.) intervals] along the track. The accumulated errors for the tractor …

Water Vapor Transport Parameters Of A Cast Wheat Gluten Film, Soumya Roy, Aristippos Gennadios, Curtis Weller, Robert F. Testin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Understanding the mode of transport of water vapor through the film is important for improving the moisture barrier properties of wheat gluten (WG) films. Effective permeability (P_eff), solubility (S_eff), and diffusion (D_eff) coefficients of a hydrophilic cast WG film were determined at 25°C within the relative humidity (RH) range of 0–84% (with a 9–13% RH gradient between upstream and downstream water vapor flux). P_eff, S_eff, and D_eff increased substantially as the RH gradient moved upwards in the RH spectrum. P_eff increased by four orders of …

Effect Of Sample Complexity On Quantification Of Analytes In Aqueous Samples By Near-Infrared Spectroscopy, Mark R. Riley, Mark A. Arnold, David W. Murhammer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study was undertaken to quantitate the impact of increasing sample complexity on near-infrared spectroscopic (NIRS) measurements of small molecules in aqueous solutions with varying numbers of components. Samples with 2, 6, or 10 varying components were investigated. Within the 10-component samples, three analytes were quantified with errors below 6% and seven of the analytes were quantified with errors below 10%. An increase in the number of varying components can substantially increase the error associated with measurement. A comparison of measurement errors across sample sets, as gauged by the standard error of prediction (SEP), reveals that an increase in the …

Production And Purification Of The Heavy Chain Fragment C Of Botulinum Neurotoxin, Serotype A, Expressed In The Methylotrophic Yeast Pichia Pastoris, Karen J. Potter, Wenhui Zhang, Leonard A. Smith, Michael M. Meagher

Michael Meagher Publications

A recombinant Hc fragment of botulinum neurotoxin, serotype A (rBoNTA(Hc)), has been successfully expressed in a Mutt strain of the methylotrophic yeast Pichia pastoris for use as an antigen in a proposed human vaccine. Fermentation employed glycerol batch, glycerol-fed batch, and methanol-fed batch phases to achieve high cell density. Induction times were short to maximize rBoNTA(H_c) production while minimizing proteolytic degradation. Concentration of rBoNTA(H_c) in yeast cell lysates was generally 1-2% of the total protein based on ELISA analysis. The H_c fragment was purified from cell lysates using a multistep ion-exchange (IEC) chromatographic process, including …

Rbcs Suppressor Mutations Improve The Thermal Stability And Co2/O2 Specificity Of Rbcl-Mutant Ribulose-1,5-Bisphosphate Carboxylaseyoxygenase, Yu-Chan Du, Seokjoo Hong, Robert J. Spreitzer

Department of Biochemistry: Faculty Publications

In the green alga Chlamydomonas reinhardtii, a Leu²⁹⁰-to-Phe (L²⁹⁰F) substitution in the large subunit of ribulose-1,5-bisphosphate carboxylaseyoxygenase (Rubisco), which is coded by the chloroplast rbcL gene, was previously found to be suppressed by second-site Ala222-to-Thr and Val²⁶²-to-Leu substitutions. These substitutions complement the photosynthesis deficiency of the L290F mutant by restoring the decreased thermal stability, catalytic efficiency, and CO₂/O₂ specificity of the mutant enzyme back to wild-type values. Because residues 222, 262, and 290 interact with the loop between β strands A and B of the Rubisco small subunit, which is …

Multiple Factors Independently Regulate Hila And Invasion Gene Expression In Salmonella Enterica Serovar Typhimurium, Robin L. Lucas, C. Phoebe Lostroh, Concetta C. Dirusso, Michael P. Spector, Barry L. Wanner, Catherine A. Lee

Department of Biochemistry: Faculty Publications

HilA activates the expression of Salmonella enterica serovar Typhimurium invasion genes. To learn more

about regulation of hilA, we isolated Tn5 mutants exhibiting reduced hilA and/or invasion gene expression. In

addition to expected mutations, we identified Tn5 insertions in pstS, fadD, flhD, flhC, and fliA. Analysis of the

pstS mutant indicates that hilA and invasion genes are repressed by the response regulator PhoB in the absence

of the Pst high-affinity inorganic phosphate uptake system. This system is required for negative control of the

PhoR-PhoB two-component regulatory system, suggesting that hilA expression may …

Multiple Factors Independently Regulate Hila And Invasion Gene Expression In Salmonella Enterica Serovar Typhimurium, Robin L. Lucas, C. Phoebe Lostroh, Concetta C. Dirusso, Michael P. Spector, Barry L. Wanner, Catherine A. Lee

Department of Biochemistry: Faculty Publications

HilA activates the expression of Salmonella enterica serovar Typhimurium invasion genes. To learn more

about regulation of hilA, we isolated Tn5 mutants exhibiting reduced hilA and/or invasion gene expression. In

addition to expected mutations, we identified Tn5 insertions in pstS, fadD, flhD, flhC, and fliA. Analysis of the

pstS mutant indicates that hilA and invasion genes are repressed by the response regulator PhoB in the absence

of the Pst high-affinity inorganic phosphate uptake system. This system is required for negative control of the

PhoR-PhoB two-component regulatory system, suggesting that hilA expression may …

Two-Step Processing Of Human Frataxin By Mitochondrial Processing Peptidase, Patrizia Cavadini, Jiri Adamec, Franco Taroni, Oleksandr Gakh, Grazia Isaya

Department of Biochemistry: Faculty Publications

We showed previously that maturation of the human

frataxin precursor (p-fxn) involves two cleavages by the

mitochondrial processing peptidase (MPP). This observation

was not confirmed by another group, however,

who reported only one cleavage. Here, we demonstrate

conclusively that MPP cleaves p-fxn in two sequential

steps, yielding a 18,826-Da intermediate (i-fxn) and a

17,255-Da mature (m-fxn) form, the latter corresponding

to endogenous frataxin in human tissues. The two cleavages

occur between residues 41–42 and 55–56, and both

match the MPP consensus sequence RX ↓ (X/S). Recombinant

rat and yeast MPP catalyze the pài step 4 and 40 …

Job Compensation In The Biotechnology Core Laboratory, Debra A. Mcmillen, William M. Old, Janice L. Bleibaum, Charles M. Nicolet, Katheryn R. Resing, Gautam Sarath, Satya P. Yadav

Gautam Sarath Publications

The results of a poll of core facility professionals by the Association of Biomolecular Resource Facilities (ABRF) Survey Committee.

Stochastic Variation In Food Availability Influences Weight And Age At Maturity, Brigitte Tenhumberg, Andrew J. Tyre, Bernie Roitberg

School of Biological Sciences: Faculty Publications

Variation in mean food availability, and in the variance around the mean, affects the growth rate during development. Previous theoretical work on the influence of environmental quality or growth rates on the phenotypic traits age and size at maturation assumed that there is no variation in growth rate or food availability within a generation. We develop a stochastic dynamic programming (SDP) model of the foraging behavior of aphidophagous syrphids, and use this model to predict when syrphids should pupate (mature) when average food availability changes, or varies stochastically, during development. The optimal strategy takes into account not only the availability …

Patterns Of Annual Seed Production By Northern Hemisphere Trees: A Global Perspective, Walter D. Koenig, Johannes M.H. Knops

School of Biological Sciences: Faculty Publications

We tested whether annual seed production (masting or mast fruiting) in Northern Hemisphere trees is an evolved strategy or a consequence of resource tracking by comparing masting patterns with those of annual rainfall and mean summer temperatures, two environmental variables likely to correlate with available resources. There were generally significant negative autocorrelations between the seed crop in year x and year x+1 (year x+2 in species of Quercus requiring 2 yr to mature acorns), as expected if resources are depleted in mast years in part by switching resources from growth to reproduction. Spatial autocorrelation in annual seed production generally declined …

Learning Improves Growth Rate In Grasshoppers, Reuven Dukas, Elizabeth A. Bernays

School of Biological Sciences: Faculty Publications

To quantify the adaptive significance of insect learning, we documented the behavior and growth rate of grasshoppers (Schistocerca americana) in an environment containing two artificial food types, one providing a balanced diet of protein and carbohydrate, which maximizes growth, and the other being carbohydratedeficient, which is unsuitable for growth. Grasshoppers in the Learning treatment experienced a predictable environment, where the spatial location, taste, and color of each food source remained constant throughout the experiment. In contrast, grasshoppers of the Random treatment developed in a temporally varying environment, where the spatial location, taste, and color of the balanced and …

Clonal Growth Of Lithospermum Caroliniense (Boraginaceae) In Contrasting Sand Dune Habitats, Stephen G. Weller, Kathleen H. Keeler, Barbara A. Thomson

School of Biological Sciences: Faculty Publications

The occurrence of clonal growth of distylous Lithospermum caroliniense was investigated in a population in the Nebraska Sandhills, an area where sand dunes have been relatively stable for at least 1,500–3,000 yr, and compared to a population occurring at the Indiana Dunes, an area of active sand dune formation. Spatial autocorrelation analysis indicated the occurrence of significant clonal propagation of genetically based floral morphs at Arapaho Prairie, but not for the Indiana Dunes. Apparent clonal growth in the Sandhills population had no overall negative effect on pollen deposition or fecundity relative to the Indiana population, although in some large clones …

Surviving The Flood: Plastron Respiration In The Non-Tracheate Arthropod Phrynus Marginemaculatus (Amblypygi: Arachnida), Eileen Hebets, Reginald F. Chapman

Eileen Hebets Publications

Specimens of Phrynus marginemaculatus can remain responsive when submerged in water for more than 24 hours. Behavioral data indicate that P. marginemaculatus utilizes dissolved oxygen from the surrounding water. Scanning electron miscroscopy and light microscope sections show cuticular modifications for plastron respiration. All previous examples of plastron respiration have involved animals with tracheal systems, but amblypygids respire through the use of two pairs of book lungs. This study provides the first example of plastron respiration not only in the order Amblypygi, but also, in any non-tracheate arthropod.

Oxidative Stress Resistance: A Robust Correlated Response To Selection In Extended Longevity Lines Of Drosophila Melanogaster?, Lawrence G. Harshman, Beth A. Haberer

Lawrence G. Harshman Publications

Stress resistance is associated with longevity in Drosophila melanogaster and other model organisms used for genetic research. The present study tests for oxidative stress resistance in one set of lines selected for late-life reproduction and extended longevity. Both females and males from the selected lines were appreciably more resistant to oxidative stress than were flies from the control lines. A relative increase in oxidative stress resistance is a correlated response to selection in this laboratory selection experiment. Increased oxidative stress resistance appears to be a relatively robust correlated response to laboratory selection for late-life reproduction and extended longevity.

Dispersion And Site Fidelity In A Tent-Roosting Population Of The Short-Nosed Fruit Bat (Cynopterus Sphinx) In Southern India, Jay F. Storz, J. Balasingh, P. Thiruchenthil Nathan, K. Emmanuel, Thomas H. Kunz

Jay F. Storz Publications

Patterns of dispersion and site fidelity were investigated in a tent-roosting population of the short-nosed fruit bat, Cynopterus sphinx (Megachiroptera), in southern India. A local population of C. sphinx occupied diurnal roosts in a variable subset of 45 stem tents constructed within the dense foliage of mast trees (Polyalthia longifolia). Individually marked tent-roosting bats were visually censused over the course of a 38-d interval spanning the postpartum oestrus period. On any given day, 33.3-85.7% (mean = 60.8%, SD = 14.2) of adult males roosted singly, with the remainder holding harems of 1-10 breeding females (mean = 3.01, SD …

Rhinocyllus Conicus -- Insights To Improve Predictability And Minimize Risk Of Biological Control Of Weeds, Svata M. Louda

Svata M. Louda Publications

A review of information on the release of Rhinocyllus conicus to control of Carduus spp. thistles in North America suggests at least 8 lessons for future biological control efforts. These lessons include the need for: 1) better a priori quantification of the occurrence and ecological effects of the weed; 2) improved incorporation of ecological criteria to supplement the phylogenetic information used to select plants for pre-release testing; 3) increased assessment of plausible direct and indirect ecological interactions when an agent looks promising but feeding tests suggest it is not strictly monophagous, including ecological factors determining host use and limiting population …

Predicting Non-Target Ecological Effects Of Biological Control Agents: Evidence From Rhinocyllus Conicus, Svata M. Louda, A. E. Arnett

Svata M. Louda Publications

The discovery and quantification of significant non-target ecological effects of Rhinocyllus conicus on native species in the northcentral USA provides the opportunity to experimentally evaluate factors that might help predict non-target host plant use, magnitude of direct impact with transference, and indirect effects mediated by trophic interactions. The relevance for biocontrol risk assessment of at least four important ecological relationships has emerged from these studies so far. These relationships include the role played in interaction outcome and ecological risk by: 1) ecological similarity of potential host plants, as well as phylogenetic distance; 2) synchrony of critical stages between insect and …

A Century Of Ornithology In Nebraska: A Personal View, Paul A. Johnsgard

Papers in Ornithology

The Nebraska Ornithologists’ Union celebrated its centennial year during 1999. During more than 65 years it has published a quarterly journal, the Nebraska Bird Review, and has also published several proceedings of annual meetings as well as special or “occasional” publications. During this same century one native Nebraska bird species (Passenger Pigeon) has become extinct, another (Eskimo Curlew) has possibly become extinct, and at least 15 species apparently have been extirpated as breeding species in the state. Additionally at least seven species have begun breeding successfully in the state, either through purposeful or accidental human efforts, or by range …

Role Of Esterase Gp70 And Its Influence On Growth And Development Of Dictyostelium Discoideum, Aidong Yuan, Catherine P. Chia

Papers in Microbiology

Gp70 is an esterase originally called crystal protein because of its presence in crystalline structures in aggregation-competent Dictyostelium discoideum cells. Although postulated to break down spore coats, the function of gp70 in vivo was incompletely investigated. Our immunolocalization and biochemical studies of vegetative D. discoideum amoebae show that gp70 was recruited to phagosomes and found in lysosomes. Purified gp70 was effective at hydrolyzing naphthyl substrates with acyl chains typical of lipids and lipopolysaccharides, indicating that the gp70 was involved in digesting endocytosed molecules. The activity of purified gp70 was inhibited by reductants that retarded its electrophoretic mobility and verified the …

Meningeal Worm In Deer From Western Nebraska, David W. Oates, Mauritz C. Sterner, Ed Boyd

Harold W. Manter Laboratory of Parasitology: Faculty Publications

One hundred seventy-eight whitetailed deer (Odocoileus virginianus) and 275 mule deer (Odocoileus hemionus) collected from locker plants in the western 2/3 of Nebraska (USA) in November 1997 were examined for the meningeal worm (Parelaphostrongylus tenuis). Parelaphostrongylus tenuis was identified in 17 (10%) of 168 white-tailed deer and in one (<1%) of 273 mule deer. This is the first naturally occurring infection of P. tenuis recorded in a mule deer.

Molecular And Morphometric Evidence For Separate Species Of Uncinaria (Nematoda: Ancylostomatidae) In California Sea Lions And Northern Fur Seals: Hypothesis Testing Supplants Verification, Steven A. Nadler, Byron J. Adams, Eugene T. Lyons, Robert L. Delong, Sharon R. Melin

Harold W. Manter Laboratory of Parasitology: Faculty Publications

California sea lions (Zalophus californianus) and northern fur seals (Callorhinus ursinus) are each believed to host distinct hookworm species (Uncinaria spp.). However, a recent morphometric analysis suggested that a single species parasitizes multiple pinniped hosts, and that the observed differences are host-induced. To explore the systematics of these hookworms and test these competing hypotheses, we obtained nucleotide sequences of nuclear ribosomal DNA (D2/D3 28S, D18/D19 28S, and internal transcribed spacer [ITS] regions) from 20 individual hookworms parasitizing California sea lion and northern fur seal pups where their breeding grounds are sympatric. Five individuals from an …

Molecular Systematics Of Mesocestoides Spp. (Cestoda: Mesocestoididae) From Domestic Dogs (Canis Familiaris) And Coyotes (Canis Latrans), Paul R. Crosbie, Steven A. Nadler, Edward G. Platzer, Cynthia Kerner, J. Mariaux, Walter M. Boyce

Harold W. Manter Laboratory of Parasitology: Faculty Publications

The genus Mesocestoides Vaillant, 1863 includes tapeworms of uncertain phylogenetic affinities and with poorly defined life histories. We previously documented 11 cases of peritoneal cestodiasis in dogs (Canis familiaris L.) in western North America caused by metacestodes of Mesocestoides spp. In the current study, DNA sequences were obtained from metacestodes collected from these dogs (n = 10), as well as proglottids from dogs (n = 3) and coyotes (Canis latrans Say, 1823 [n = 2]), and tetrathyridia representing laboratory isolates of M. corti (n = 3), and these data were analyzed phylogenetically. Two nuclear genetic markers, 18S ribosomal …

Phylogeny Of The Ascaridoidea (Nematoda: Ascaridida) Based On Three Genes And Morphology: Hypotheses Of Structural And Sequence Evolution, Steven A. Nadler, Deborah S. S. Hudspeth

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Ascaridoid nematodes parasitize the gastrointestinal tract of vertebrate definitive hosts and are represented by more than 50 described genera. We used 582 nucleotides (83% of the coding sequence) of the mitochondrial gene cytochrome oxidase subunit 2, in combination with published small- and large-subunit nuclear rDNA sequences (2,557 characters) and morphological data (20 characters), to produce a phylogenetic hypothesis for representatives of this superfamily. This combined evidence phylogeny strongly supported clades that, with 1 exception, were consistent with Fagerholm’s 1991 classification. Parsimony mapping of character states on the combined evidence tree was used to develop hypotheses for the evolution of morphological, …

Phylogenetic Relationships Among Species Of Contracaecum Railliet & Henry, 1912 And Phocascaris Høst, 1932 (Nematoda: Ascaridoidea) Based On Nuclear Rdna Sequence Data, Steven A. Nadler, S. D'Amelio, H. P. Fagerholm, B. Berland, L. Paggi

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Nuclear-encoded large-subunit ribosomal DNA sequences were used to infer a phylogenetic hypothesis for 17 taxa (16 nominal species) of the genera Contracaecum and Phocascaris. Phylogenetic trees based on these data have been used to assess the validity of the taxonomic distinction between these genera, which was based on the presence or absence of certain structural features, rather than on explicit hypotheses of evolutionary history. Phylogenetic hypotheses based on parsimony, likelihood, and neighbor-joining analyses of these sequence data strongly support the hypothesis that species of Phocascaris are nested within the clade of Contracaecum species hosted by phocid seals, and are …

Molecular Phylogeny Of Clade Iii Nematodes Reveals Multiple Origins Of Tissue Parasitism, Steven A. Nadler, R. A. Carreno, H. Mejía-Madrid, J. Ullberg, C. Pagan, R. Houston, Jean-Pierre Hugot

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Molecular phylogenetic analyses of 113 taxa representing Ascaridida, Rhigonematida, Spirurida and Oxyurida were used to infer a more comprehensive phylogenetic hypothesis for representatives of ‘clade III’. The posterior probability of multiple alignment sites was used to exclude or weight characters, yielding datasets that were analysed using maximum parsimony, likelihood, and Bayesian inference methods. Phylogenetic results were robust to differences among inference methods for most high-level taxonomic groups, but some clades were sensitive to treatments of characters reflecting differences in alignment ambiguity. Taxa representing Camallanoidea, Oxyurida, Physalopteroidea, Raphidascarididae, and Skrjabillanidae were monophyletic in all 9 analyses whereas Ascaridida, Ascarididae, Anisakidae, Cosmocercoidea, …

A Cox2 Molecular Phylogeny Of The Peronosporomycetes, Deborah S.S. Hudspeth, Steven A. Nadler, Michael E.S. Hudspeth

Harold W. Manter Laboratory of Parasitology: Faculty Publications

The evolutionary history of the mitochondrial COX2 locus has been used to infer the phylogenetic relationships among 15 peronosporomycete and a hyphochytriomycete species. This molecular phylogenetic analysis at both the ordinal and generic levels provides strong evidence for the recognition of the Saprolegniomycetidae and the Peronosporomycetidae as natural groups, and for the monophyly of the Saprolegniales, Leptomitales and Pythiales. A three amino acid insertion/deletion event (indel) has been identified as a putative synapomorphy for the Saprolegniales. Parsimony mapping of 12 morphological and biochemical characters on the COX2 molecular phylogeny yields an hypothesis for peronosporomycete ancestral states and shared-derived features.