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A Surface-Associated Activity Trap For Capturing Water-Surface And Aquatic Invertebrates In Wetlands, Mark A. Hanson, Christiane C. Roy, Ned H. Euliss Jr., Kyle D. Zimmer, Michael R. Riggs, Malcolm G. Butler

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

We developed a surface-associated activity trap (SAT) for sampling aquatic invertebrates in wetlands. We compared performance of this trap with that of a conventional activity trap (AT) based on nondetection rates and relative abundance estimates for 13 taxa of common wetland invertebrates and for taxon richness using data from experiments in constructed wetlands. Taxon-specific non-detection rates for ATs generally exceeded those of SATs, and largest improvements using SATs were for Chironomidae and Gastropoda. SATs were efficient at capturing cladocera, Chironomidae, Gastropoda, total Crustacea, and multiple taxa (taxon richness) but were only slightly better than ATs at capturing Dytiscidae. Temporal differences …

A Record Large Wolf, Canis Lupus, Pack In Minnesota, L. David Mech

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

This report documents a pack of 22-23 Wolves (Canis lupus) in central Minnesota. This is larger than the largest pack previously observed on the mainland in the midwestern U.s. during 650 wolf pack-years. Because this record-large pack preyed on White-tailed Deer (Odocoileus virginianus), one of the Wolfs smaller prey, it is evidence that pack size and prey size are not tightly related. It also indicates the size that Wolf packs can attain in the area if fully protected from human persecution.

Lack Of Reproduction In Muskoxen And Arctic Hares Caused By Early Winter?, L. David Mech

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

A lack of young muskoxen (Ovibos moschatus) and arctic hares (Lepus arcticus) in the Eureka area of Ellesmere Island, Northwest Territories (now Nunavut), Canada, was observed during summer 1998, in contrast to most other years since 1986. Evidence of malnourished muskoxen was also found. Early winter weather and a consequent 50% reduction of the 1997 summer replenishment period appeared to be the most likely cause, giving rise to a new hypothesis about conditions that might cause adverse demographic effects in arctic herbivores.

Durant l’été 1998, et ce, à la différence de la plupart des années depuis …

Accuracy And Precision Of Estimating Age Of Gray Wolves By Tooth Wear, Philip S. Gipson, Warren B. Ballard, Ronald M. Nowak, L. David Mech

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

We evaluated the accuracy and precision of tooth wear for aging gray wolves (Canis lupus) from Alaska, Minnesota, and Ontario based on 47 known-age or known-minimum-age skuIIs. Estimates of age using tooth wear and a commercial cementum annuli-aging service were useful for wolves up to 14 years old. The precision of estimates from cementum annuli was greater than estimates from tooth wear, but tooth wear estimates are more applicable in the field. We tended to overestimate age by 1-2 years and occasionaIIy by 3 or 4 years. The commercial service aged young wolves with cementum annuli to within …

Prolonged Winter Undernutrition And The Interpretation Of Urinary Allantoin:Creatinine Ratios In White-Tailed Deer, Glenn D. Delgiudice, Ken D. Kerr, L. David Mech, Ulysses S. Seal

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

The urinary allantoin:creatinine (A:C) ratio (expressed in micromoles of allantoin to micromoles of creatinine) has shown potential as an index of recent winter energy intake in preliminary controlled studies of elk (Cervus elaphus) involving mild condition deterioration (up to 11% loss of body mass). To ensure reliable nutritional assessments of free-ranging cervids by measuring A:C ratios of urine in snow, it is essential to extend this work. We assessed the effect of moderate and severe winter nutritional restriction on urinary A:C ratios of captive white-tailed deer (Odocoileus virginianus) that lost up to 32% body mass and …

Baseline Assessment Of The Use Of A Small Missouri River Backwater By Fish At Ponca State Park In Dixon County, Nebraska, A. Luke Wallace

United States Army Corps of Engineers, Omaha District

Ponca State Park is located adjacent to the Missouri River near the town of Ponca in Dixon County, Nebraska between river miles 753.8 and 755.3. This portion of the river is a 59-mile, unchannelized segment that has been designated as the Missouri National Recreational River under the Wild and Scenic Rivers Act. The majority of the park is situated high on bluffs that overlook the Missouri River. Until recently, the park had only a small amount of easily accessible river frontage. In 1999, the Nebraska Game and Parks Commission (NGPC) acquired an additional 295 acres of river bottomland on the …

Waterfowl Research Priorities In The Northern Great Plains, Robert R. Cox Jr., Douglas H. Johnson, Michael A. Johnson, Ronald E. Kirby, Jeffrey W Nelson, Ronald E. Reynolds

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

It is necessary periodically to identify research priorities so that future research will be directed toward the most pertinent issues in waterfowl ecology and management. To that end, Northern Prairie Wildlife Research Center convened a quorum of experts on the ecology of breeding waterfowl, the Waterfowl Working Group, to 1) develop a mission statement, 2) identify waterfowl research priorities in the northern Great Plains, and 3) determine the frequency for re-identifying research needs. Research needs (nonprioritized) identified by the group and described in detail herein included: 1) determine effects of landscape factors on demographics and recruitment of ducks in the …

Temporal Flexibility Of Reproduction In Temperate-Breeding Dabbling Ducks, Gary Krapu

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

I compared nesting intervals during three consecutive years in five species of temperate-nesting dabbling ducks (Mallard [Anas platyrhynchos], Northern Pintail [Anas acuta], Northern Shoveler [Anas clypeata], Blue-winged Teal [Anas discors], Gadwall [Anas strepera]) and assessed whether differences existed in timing of refractoriness. Most nesting by females of all five species ended by the summer solstice. Nesting ended earliest for Northern Shovelers and Northern Pintails and latest for Gadwalls. Some Mallards, Blue-winged Teal, and Gadwalls continued to nest into mid- and late summer, whereas Northern Shovelers and Northern Pintails did not. …

Habitat Erosion Protection Analysis Missouri National Recreational River Nebraska And South Dakota

United States Army Corps of Engineers, Omaha District

The Corps was tasked by the National Park Service to detennine if erosion protection measures were needed to prevent further decline in cottonwood forest within the Missouri National Recreational River. The 1990's had three unusually high water years resulting in increased runoff and dam discharges, with resultant increased erosion. Concern about erosion of cottonwood forests was expressed by the public during public meetings held by the National Park Service and the Corps during 1999. Severe erosion was also evident in the comparison of aerial maps from 1985 to those from 1997. Forested habitat is considered a "wildlife value" for the …

Wolf-Bison Interactions In Yellowstone National Park, Douglas Smith, L. David Mech, Mary Meagher, Wendy Clark, Rosemary Jaffe, Michael Phillips, John A. Mack

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

We studied interactions of reintroduced wolves (Canis lupus) with bison (Bison bison) in Yellowstone National Park. Only 2 of 41 wolves in this study had been exposed to bison before their translocation. Wolves were more successful killing elk (Cervus elaphus) than bison, and elk were more abundant than bison, so elk were the primary prey of wolves. Except for a lone emaciated bison calf killed by 8 1-year-old wolves 21 days after their release, the 1st documented kill occurred 25 months after wolves were released. Fourteen bison kills were documented from April 1995 through …

The Role Of Chitinase Production By Stenotrophomonas Maltophilia Strain C3 In Biological Control Of Bipolaris Sorokiniana, Zhongge Zhang, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

The role of chitinase production by Stenotrophomonas maltophilia strain C3 in biological control of leaf spot on tall fescue (Festuca arundinacea), caused by Bipolaris sorokiniana, was investigated in vitro and in vivo. The filtrate of a broth culture of C3, with chitin as the carbon source, was separated into fractions. A high molecular-weight fraction (>8 kDa) was chitinolytic and more inhibitory than a low-molecularweight, nonchitinolytic fraction to conidial germination and hyphal growth by B. sorokiniana and to leaf spot development. A protein fraction derived by ammonium sulfate precipitation and a chitinase fraction purified by chitin affinity …

Soybean Cyst Nematode Reproduction In The North Central United States, J. Wang, P. A. Donald, T. L. Niblack, G. W. Bird, J. Faghihi, J. M. Ferris, C. Grau, D. J. Jardine, P. E. Lipps, A. E. Macguidwin, H. Melakeberhan, G. R. Noel, P. Pierson, P. M. Riedel, P. R. Sellers, W. C. Stienstra, T. C. Todd, G. L. Tylka, T. A. Wheeler, D. S. Wysong

Department of Plant Pathology: Faculty Publications

An experiment was conducted in Heterodera glycines–infested fields in 40 north central U.S. environments (21 sites in 1994 and 19 sites in 1995) to assess reproduction of this nematode. Two resistant and two susceptible soybean cultivars from each of the maturity groups (MG) I through IV were grown at each site in 6.1 m by 4 row plots. Soil samples were collected from each plot at planting and harvest and processed at Iowa State University to determine H. glycines initial (Pi) and final (Pf) population densities as eggs per 100 cm3 of soil. Overall, reproduction (Pf/Pi) of H. glycines …

Isovolumic Regulation In Nervous Tissue: A Novel Mechanism Of Cell Volume Regulation, O. Quesada, R. Franco, K. Hernandez-Fonseca, K. Tuz

School of Veterinary and Biomedical Sciences: Faculty Publications

Cell volume regulation is a property present in most animal cell lineages that allows them to recover their original volume after events of swelling or shrinkage. Such events can be caused by changes in external osmolarity or to osmotic gradients generated during normal cell functioning.4,6 The mechanism of cell volume regulation involves transmembrane fluxes of osmotically active solutes in the necessary direction to counteract the net gain or loss of intracellular water.9 The process through which cells recover their normal volume after swelling is named Regulatory Volume Decrease (RVD). This consists of the efflux of inorganic osmolytes, such as K …

Nest Predation On Black-Tailed Prairie Dog Colonies, Bruce Baker, Thomas R. Stanley, Glenn Plumb

United States Geological Survey: Staff Publications

Nest predation is the principal cause of mortality for many grassland birds. Predation rates may be higher on prairie dog colonies because they may have less available nesting cover and may increase predator abundance. We compared 14-day nest predation rates for 1,764 artificial nests on 102 black-tailed prairie dog (Cynovnys ludovicianus) colonies and their paired off-colony sites (similar habitat lacking prairie dogs) from 14 May to 26 June 1998 in South Dakota and Wyoming. Predation rates on colonies (66.2 ± 2.2%; x ± SE) were 29.5% higher than at off-colony sites (51.1 ± 2.7%). Nesting cover on colonies …

Establishment Of Big Bluestem And Illinois Bundleflower Mixtures With Imazapic And Imazethapyr, Daniel D. Beran, Robert A. Masters, Roch E. Gaussoin, Fernando Rivas-Pantoja

Department of Agronomy and Horticulture: Faculty Publications

Weeds interfere with establishment of native grasses and legumes. A study was conducted to determine the influence of imazapic¹ [(±)- 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]- 5-methyl-3-pyridinecarboxylic acid] and imazethapyr [2-[4,5-dihydro- 4-methyl -4 - (1- methylethyl) -5 -oxo-1H- imidazol -2 - yl]5- ethyl -3- pyridinecarboxylic acid] on weed control and establishment of ‘Pawnee’ big bluestem (Andropogon gerardii Vitman var. gerardii Vitman) and Illinois bundleflower [Desmanthus illinoensis (Michx.) MacMill.] planted in three binary mixtures of 220:110, 165:165, and 110:220 pure live seed (PLS) m^-2. Mixtures were seeded at cropland sites near Clay Center, Mead, and Lincoln, NE. Imazapic and imazeth- apyr …

Bean Leaf Beetle (Coleoptera: Chrysomelidae) Abundance In Soybean Fields Protected And Unprotected By Shelterbelts, Stephen D. Danielson, James R. Brandle, Laurie Hodges, P. Srinivas

Department of Agronomy and Horticulture: Faculty Publications

The bean leaf beetle, Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae), is a major insect pest of soybean in Nebraska and throughout much of the Midwest. This insect overwinters in the adult stage in litter in wooded areas such as shelterbelts. Historically, crop producers have been unsure of the merits of shelterbelts, especially if nearby crops are more likely to be infested by insect pests as a result. In this study, bean leaf beetle adults were sampled during the season by visually counting the number of beetles found on soybean plants early in the season and by sweep net sampling once plants …

Classroom Management Issues For Teaching Assistants, Jiali Luo, Laurie H Bellows, Marilyn Grady

Department of Educational Administration: Faculty Publications

For many graduate teaching assistants, the task of planning, organizing, motivating, and controlling classroom environments can be overwhelming. Empirical research pertaining to major classroom management problems experienced by TAs is scarce. This article is a report of a survey study regarding TA classroom management at a large, land-grant Research 1 University. The study provides specific information about TAs’ perceptions of classroom management experiences and concerns based on TA type, gender, teaching experience, and academic discipline. The results of the study indicate that international and U.S. TAs experienced many common problems, but each of the two types of TAs also had …

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.) …

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) …

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 …