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Experimental Infection Of Nontarget Species Of Rodents And Birds With Brucella Abortus Strain Rb51 Vaccine, Matt C. Januszewski, Steven C. Olsen, Robert G. Mclean, Larry Clark, Jack C. Rhyan

United States Department of Agriculture Wildlife Services: Staff Publications

The Brucella abortus vaccine strain RB51 (SRB51) is being considered for use in the management of brucellosis in wild bison (Bison bison) and elk (Cervus elaphus) populations in the Greater Yellowstone Area (USA). Evaluation of the vaccine’s safety in non-target species was considered necessary prior to field use. Between June 1998 and December 1999, ground squirrels (Spermophilus richardsonii, n=21), deer mice (Peromyscus maniculatus, n=14), prairie voles (Microtus ochrogaster, n=21), and ravens (Corvus corax, n=13) were orally inoculated with SRB51 or physiologic saline. Oral and …

Performance Of Intercom For Predicting Corn– Velvetleaf Interference Across North-Central United States, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Cost-effective weed management requires accurate estimates of yield and the potential yield loss resulting from weed infestations. However, crop yield and the effects of weeds are highly variable across years and locations. Ecophysiological models may be useful for predicting the effects of environment and management on crop and weed growth and competitive ability. Ability of the model INTERCOM to predict corn (Zea mays) growth and yield, velvetleaf (Abutilon theophrasti) interference on corn yield loss, and single-year economic threshold velvetleaf density (T_e) was evaluated using 13 data sets collected in four states. Predicted and observed …

Storage And Handling Characteristics Of Trinexapac-Ethyl Treated Kentucky Bluegrass Sod, Neil L. Heckman, Garald L. Horse, Roch E. Gaussoin, Kevin Frank

Department of Agronomy and Horticulture: Faculty Publications

Internal heating during sod storage can lead to plant deterioration and is a limiting factor in sod transportation. Storage practices such as the use of refrigeration and vacuum packaging have increased storage time; however, these are usually not practical or economical. Experiments were conducted to develop a feasible growth regulator management technique, using trinexapac-ethyl, to increase the storage life of Kentucky bluegrass (Poa pratensis L.) sod. Experimental setup for all experiments was a completely randomized design with a 2 (trinexapac-ethyl vs. control) × 3 (storage times) factorial treatment arrangement with 3 replications. Trinexapac-ethyl was applied at 0.23 kg·ha^{–1 …}

Tillage And Fallow Effects On Selected Soil Quality Characteristics Of Former Conservation Reserve Program Sites, John E. Gilley, John W. Doran, Bahman Eghball

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tillage and fallow have been suggested as management options for converting Conservation Reserve Program (CRP) areas to cropland. This study was conducted to measure selected soil quality characteristics of former CRP sites in Mississippi, Nebraska, and South Dakota that were tilled and then left fallow for 21 or 22 months. Soil samples from depth intervals of 0-7.6 cm and 0-30.5 cm were collected for laboratory assessment of the following soil quality indicators: bulk density, EC, pH, total C, organic C, total N, NO₃-N, NH₄-N, PO₄-P, biomass C, biomass N, anaerobic NH₄-N, lab …

Phosphorus Risk Assessment Index Evaluation Using Runoff Measurements, Bahman Eghball, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

An index to evaluate the phosphorus (P) pollution potential of agricultural fields was proposed by Lemunyon and Gilbert in 1993. Data from three rainfall simulation studies were used to evaluate the relative importance of the variables in the P index. These studies included plots containing sorghum (Sorghum bicolor L.), winter wheat (Triticum aestivum L.), and corn (Zea mays L.) residues on which chemical fertilizer and composted or noncomposted beef cattle feedlot manure were applied under no-till and disked conditions. The factors of erosion, runoff, soil P level P application source, and method, and rate of P addition …

Reducing Long-Term Atrazine Runoff From South Central Nebraska, Walter Scott Gorneau, Thomas G. Franti, Brian L. Benham, Steve D. Comfort

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Heavy reliance on chemical weed control in field crops of South Central Nebraska has resulted in the appearance of atrazine at concentrations greater than established drinking water standards. Our objective was to evaluate the best management practices for atrazine runoff for the tillage and herbicide management practices common to the region under study. Field experiments were performed to measure edge–of–field atrazine and water loss from disk–till, ridge–till, and slot plant (no–till) management systems. Results indicated less water runoff from no–till (34% less) and ridge–till (36% less) than from disk–till. Similarly, atrazine loss was also less: 24% less for no–till and …

Application Of Fuzzy Logic In Automated Cow Status Monitoring, R. M. De Mol, Wayne Woldt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Sensors that measure yield, temperature, electrical conductivity of milk, and animal activity can be used for automated cow status monitoring. The occurrence of false-positive alerts, generated by a detection model, creates problems in practice. We used fuzzy logic to classify mastitis and estrus alerts; our objective was to reduce the number of false-positive alerts and not to change the level of detected cases of mastitis and estrus. Inputs for the fuzzy logic model were alerts from the detection model and additional information, such as the reproductive status. The output was a classification, true or false, of each alert. Only alerts …

Way-Finding And Landmarks: The Multiple Bearings Hypothesis, Alan C. Kamil, Ken Cheng

Papers in Behavior in Biological Sciences

Clark’s nutcrackers (Nucifraga columbiana) are capable of very precise searching using the metric relationships between a goal and multiple landmarks to relocate the goal location. They can judge the direction more accurately than the distance to a landmark when the landmark is distant from the goal. On the basis of these findings, we propose that nutcrackers use a set of bearings, each a measure of the direction from the goal to a different landmark, when searching for that goal. The results of a simulation demonstrate that increasing the number of landmarks used results in increasingly precise searching. This …

Search For A Hidden Goal By Clark's Nutcrackers (Nucifraga Columbiana) Is More Accurate Inside Than Outside A Landmark Array, Brett M. Gibson, Alan C. Kamil

Papers in Behavior in Biological Sciences

In three experiments in which an open-room delayed response task was used, we explored how Clark's nutcrackers use landmarks to search for a hidden goal when multiple potential goal locations were present. In Experiment 1, nutcrackers presented with three spatial samples were able to use relative local cues from an array that changed positions throughout a session to return to a hidden goal during a test. In Experiment 2, the number of samples varied from one to three prior to the test. The nutcrackers performed as well with one sample as with two or three samples. In Experiment 3, we …

The Use Of Relative And Absolute Bearings By Clark's Nutcrackers, Nucifraga Columbiana, Juli E. Jones, Alan C. Kamil

Papers in Behavior in Biological Sciences

Two groups of Clark's nutcrackers were trained to find buried seeds whose location was defined by a constant angle from two landmarks whose interlandmark distance and position in the room varied across trials. The first group had a landmark array that was always placed in the same orientation with respect to the walls, allowing the animals to use both relative and absolute bearings. The second group had a landmark array that rotated across trials so that only relative bearings could be used to locate the seeds. The birds in each group learned the task and transferred to new interlandmark distances …

Review Of Evolution And Cognition, Edited By Cecilia Heyes And Ludwig Huber., Alan Kamil

Papers in Behavior in Biological Sciences

Heyes and Huber have edited a volume that surveys much of the current research into cognition in animals, reflecting the strengths and weaknesses of this field. The book is divided into five sections. In the first part, titled “Orientations,” four authors lay out their basic general views of the field. The first two chapters in this section are by the editors. First, Heyes makes the case for an approach to evolutionary psychology that she labels “in the round,” an approach that would encompass studies of human and nonhuman animals alike and include a broad range of contemporary evolutionary approaches. This …

Linear-Nonequilibrium Thermodynamics Theory For Coupled Heat And Mass Transport, Yaşar Demirel, Stanley I. Sandler

Yaşar Demirel Publications

Linear-nonequilibrium thermodynamics (LNET) has been used to express the entropy generation and dissipation functions representing the true forces and flows for heat and mass transport in a multicomponent fluid. These forces and flows are introduced into the phenomenological equations to formulate the coupling phenomenon between heat and mass flows. The degree of the coupling is also discussed. In the literature such coupling has been formulated incompletely and sometimes in a confusing manner. The reason for this is the lack of a proper combination of LNET theory with the phenomenological theory. The LNET theory involves identifying the conjugated flows and forces …

The Wasp-Like Protein Scar Regulates Macropinocytosis, Phagocytosis And Endosomal Membrane Flow In Dictyostelium, David J. Seastone, Ed Harris, Lesly A. Temesvari, James E. Bear, Charles L. Saxe, James Cardelli

Department of Biochemistry: Faculty Publications

Scar, a member of the WASp protein family, was discovered in Dictyostelium discoideum during a genetic screen for second-site mutations that suppressed a developmental defect. Disruption of the scar gene reduced the levels of cellular F-actin by 50%. To investigate the role of Scar in endocytosis, phagocytosis and endocytic membrane trafficking, processes that depend on actin polymerization, we have analyzed a Dictyostelium cell line that is genetically null for Scar. Rates of fluid phase macropinocytosis and phagocytosis are significantly reduced in the scar^- cell-line. In addition, exocytosis of fluid phase is delayed in these cells and movement of fluid …

Rab11-Like Gtpase Associates With And Regulates The Structure And Function Of The Contractile Vacuole System In Dictyostelium, Ed Harris, Kunito Yoshida, James Cardelli, John Bush

Department of Biochemistry: Faculty Publications

Screening of a cDNA library revealed the existence of a Dictyostelium cDNA encoding a protein 80% identical at the amino acid level to mammalian Rab11. Subcellular fractionation and immunofluorescence studies revealed that DdRab11 was exclusively associated with the ATPase proton pump-rich contractile vacuole membrane system, consisting of a reticular network and bladder-like vacuoles. Video microscopy of cells expressing GFP-DdRab11 revealed that this Rab was associated with contractile vacuolar bladders undergoing formation, fusion and expulsion of water. The association of DdRab11 with contractile vacuole membranes was disrupted when cells were exposed to either hypo-osmotic conditions or an inhibitor of the ATPase …

Selenoprotein Oxidoreductase With Specificity For Thioredoxin And Glutathione Systems, Qi-An Sun, Leo Kirnarsky, Simon Sherman, Vadim N. Gladyshev

Department of Biochemistry: Faculty Publications

Thioredoxin (Trx) and glutathione (GSH) systems are considered to be two major redox systems in animal cells. They are reduced by NADPH via Trx reductase (TR) or oxidized GSH (GSSG) reductase and further supply electrons for deoxyribonucleotide synthesis, antioxidant defense, and redox regulation of signal transduction, transcription, cell growth, and apoptosis. We cloned and characterized a pyridine nucleotide disulfide oxidoreductase, Trx and GSSG reductase (TGR), that exhibits specificity for both redox systems. This enzyme contains a selenocysteine residue encoded by the TGA codon. TGR can reduce Trx, GSSG, and a GSH-linked disulfide in in vitro assays. This unusual substrate specificity …

The Cia5 Gene Controls Formation Of The Carbon Concentrating Mechanism In Chlamydomonas Reinhardtii, Youbin Xiang, Jun Zhang, Donald P. Weeks

Department of Biochemistry: Faculty Publications

Wild-type Chlamydomonas reinhardtii cells shifted from high concentrations (5%) of CO2 to low, ambient levels (0.03%) rapidly increase transcription of mRNAs from several CO₂-responsive genes. Simultaneously, they develop a functional carbon concentrating mechanism that allows the cells to greatly increase internal levels of CO₂ and HCO₃. The cia5 mutant is defective in all of these phenotypes. A newly isolated gene, designated Cia5, restores transformed cia5 cells to the phenotype of wild-type cells. The 6,481-bp gene produces a 5.1-kb mRNA that is present constitutively in light in high and low CO₂ both in …

C3 Origins Of The C4 Pathway Regulatory Enzyme, Ppdk-Rp, C. J. Chastain, Gautam Sarath, Raymond Chollet

Gautam Sarath Publications

A current view of C₄ and CAM evolution holds that all of the constituent enzymes of the C₄ pathway preexisted in C₃ plants, albeit functioning in nonphotosynthetic capacities.

Toxicant Impacts On Density-Limited Populations: A Critical Review Of Theory, Practice, And Results, Valery E. Forbes, Richard M. Sibly, Peter Calow

Valery Forbes Publications

Most natural populations experience some density dependence, and longterm average rates of population growth are likely to be close to zero (i.e., steady state). An essential question, therefore, is how and to what extent do density-dependent effects influence the responses of populations to toxicant impacts? Here we consider three general types of interaction between density dependence and toxicant effects: additive, less than additive, and more than additive. If we know enough about the life-history dynamics of an organism and how its life-history traits are affected by density and toxicant exposure, we should be able to use life-history models to predict …

Molecular Characterization Of Cephalothorax, The Tribolium Ortholog Of Sex Combs Reduced, Carmelle D. Curtis, Jennifer A. Brisson, Mark A. Decamillis, Teresa D. Shippy, Susan J. Brown, Robin E. Denell

School of Biological Sciences: Faculty Publications

Sex combs reduced (Scr), a Hox gene located in the Antennapedia complex of Drosophila melanogaster, is required for the proper development of the labial and first thoracic segments. The Tribolium castaneum genetically defined locus Cephalothorax (Cx) is a candidate Scr ortholog based on the location of Cx in the beetle Homeotic complex and mutant effects on the labial and first thoracic segments. To address this hypothesis, we have cloned and characterized the Tribolium ortholog of Scr (TcScr). The transcription unit is less complex and encodes a smaller protein than Scr. The predicted …

Rhinocyllus Conicus: Initial Evaluation And Subsequent Ecological Impacts In North America, A. Gassmann, Svata M. Louda

School of Biological Sciences: Faculty Publications

Renewed debate over the risk of non-target effects in biological control reflects, in part, the recent quantification of direct and indirect ecological effects of the flowerhead weevil, Rhinocyllus conicus Frol., in North America. To help resolve the issue, we review the published data for R. conicus from both Europe and North America: pre-release (1961-1968), post-release (1969-1985) and more recent (1986-1999). Our aim was to determine the extent to which host range expansion on to native North American species, and the associated ecological effects, were predicted or predictable. Our overall conclusion is that more was known than is generally realized, yet …

Contrasting Effects Of Plant Richness And Composition On Insect Communities: A Field Experiment, Nick M. Haddad, David Tilman, John Haarstad, Mark Ritchie, Johannes M.H. Knops

School of Biological Sciences: Faculty Publications

We experimentally separated the effects of two components of plant diversity—plant species richness and plant functional group richness—on insect communities. Plant species richness and plant functional group richness had contrasting effects on insect abundances, a result we attributed to three factors. First, lower insect abundances at higher plant functional group richness were explained by a sampling effect, which was caused by the increasing likelihood that one low-quality group, C4 grasses, would be present and reduce average insect abundances by 25%. Second, plant biomass, which was positively related to plant functional group richness, had a strong, positive effect on insect abundances. …

Notes And Comments: Food Web Laws Or Niche Theory? Six Independent Empirical Tests, Kirk O. Winemiller, Eric R. Pianka, Laurie J. Vitt, Anthony Joern

School of Biological Sciences: Faculty Publications

Over the past 2 decades, empirical food webs have been shown to possess regular patterns of various kinds. Some of the first food web patterns were reported as “food web laws,” the most notable being the link-species scaling law. This empirically derived law described an inverse relationship between community species richness and web connectance (Cohen and Briand 1984; Cohen and Newman 1985). Subsequent evaluation of food webs constructed with more detailed data falsified (Warren 1989; Winemiller 1989a, 1990; Hall and Raffaelli 1991; Polis 1991) and modified (Warren 1990; Martinez 1991, 1992; Pimm et al. 1991; Martinez et al. 1999) many …

Optimal Patch-Leaving Behavior: A Case Study Using The Parasitoid Cotesia Rubecula, Brigitte Tenhumberg, Mike A. Keller, Hugh P. Possingham, Andrew J. Tyre

School of Biological Sciences: Faculty Publications

1. Parasitoids are predicted to spend longer in patches with more hosts, but previous work on Cotesia rubecula (Marshall) has not upheld this prediction. Tests of theoretical predictions may be affected by the definition of patch leaving behavior, which is often ambiguous.

2. In this study whole plants were considered as patches and assumed that wasps move within patches by means of walking or flying. Within-patch and between-patch flights were distinguished based on flight distance. The quality of this classification was tested statistically by examination of log-survivor curves of flight times.

3. Wasps remained longer in patches with higher host …

Using Cox’S Proportional Hazard Models To Implement Optimal Strategies: An Example From Behavioral Ecology, Brigitte Tenhumberg, M. A. Keller, Hugh P. Possingham

School of Biological Sciences: Faculty Publications

Simple behavioral rules, or “rules of thumb,” which lead to behavior that closely approximates an optimal strategy, have generated a lot of recent interest in the field of foraging behavior. In this paper, we derive rules of thumb from a stochastic simulation model in which the foragers behave optimally. We use a particular biological system: the patch leaving behavior of a parasitoid. We simulate parasitoids whose patch leaving behavior is determined by a stochastic dynamic programming (SDP) model, while allowing parasitoids to make mistakes in their estimation of host density when arriving in a patch We use Cox’s proportional hazards …

Mean Time To Extinction Of A Metapopulation With An Allee Effect, Chad Brassil

School of Biological Sciences: Faculty Publications

The incorporation of Allee effects into a simple metapopulation extinction model reveals a large non-linear reduction in mean time to extinction with small changes in an Allee limit. The extent of this reduction is dependent on the level of migration in the metapopulation. With small amounts of migration, small changes in the Allee limit result in large changes in the meantime to extinction. With higher levels of migration, the mean time to extinction is not as sensitive to changes in the Allee limit, becoming more similar to the single population case. The metapopulation modeled here is a set of nine …

Microbially Catalyzed Nitrate-Dependent Oxidation Of Biogenic Solid-Phase Fe(Ii) Compounds, Karrie A. Weber, Flynn W. Picardal, Eric E. Roden

School of Biological Sciences: Faculty Publications

The potential for microbially catalyzed NO₃^—-dependent oxidation of solid-phase Fe(II) compounds was examined using a previously described autotrophic, denitrifying, Fe(II)-oxidizing enrichment culture. The following solid-phase Fe(II)-bearing minerals were considered: microbially reduced synthetic goethite, two different end products of microbially hydrous ferric oxide (HFO) reduction (biogenic Fe₃O₄ and biogenic FeCO₃), chemically precipitated FeCO₃, and two microbially reduced iron(III) oxide-rich subsoils. The microbially reduced goethite, subsoils, and chemically precipitated FeCO₃ were subject to rapid NO₃^—-dependent Fe(II) oxidation. Significant oxidation of biogenic Fe₃O₄ was observed. Very …

Secreted Euryarchaeal Microhalocins Kill Hyperthermophilic Crenarchaea, Cynthia Haseltine, Tiffany Hill, Rafael Montalvo-Rodriguez, Samantha K. Kemper, Richard F. Shand, Paul H. Blum

School of Biological Sciences: Faculty Publications

Few antibiotics targeting members of the archaeal domain are currently available for genetic studies. Since

bacterial antibiotics are frequently directed against competing and related organisms, archaea by analogy

might produce effective antiarchaeal antibiotics. Peptide antibiotic (halocin) preparations from euryarchaeal

halophilic strains S8a, GN101, and TuA4 were found to be toxic for members of the hyperthermophilic

crenarchaeal genus Sulfolobus. No toxicity was evident against representative bacteria or eukarya. Halocin S8

(strain S8a) and halocin R1 (strain GN101) preparations were cytostatic, while halocin A4 (strain TuA4)

preparations were cytocidal. Subsequent studies focused on the use of halocin A4 preparations and Sulfolobus …

A Cost Of Reproduction In Drosophila Melanogaster: Stress Susceptibility, Adam B. Salmon, David B. Marx, Lawrence G. Harshman

Lawrence G. Harshman Publications

Little is known about physiological mechanisms that underlie the cost of reproduction. We tested the hypothesis that stress susceptibility is a cost of reproduction. In one test of our hypothesis, Dro-sophila melanogaster females were exposed to a juvenile hormone analog (methoprene) to stimulate egg production followed by stress assays. A sterile stock of D. melanogaster was employed as a control for reproduction. Exposure of fertile females to methoprene resulted in an increase in female repro-duction and increased susceptibility to oxidative stress and starvation (compared to solvent con-trols). Sterile females did not exhibit a decrease in stress resistance. Mating also stimulated …

Female Sensitivity To Diet And Irradiation Treatments Underlies Sex-Mortality Differentials In The Mediterranean Fruit Fly, James R. Carey, Pablo Liedo, Hans-Georg Müller, Jane-Ling Wang, Brad Love, Lawrence G. Harshman, Linda Partridge

Lawrence G. Harshman Publications

Large-scale experiments on medflies that were subjected to sterilizing doses of ionizing radiation (plus intact controls) and maintained on either sugar-only or full, protein-enriched diets revealed that, whereas the mortality trajectories of both intact and irradiated male cohorts maintained on both diets are similar, the mortality patterns of females are highly variable. Mean mortality rates at 35 days in male cohorts ranged from 0.2 to 0.3 but in female cohorts ranged from 0.09 to 0.35, depending on treatment. The study reports three main influences: (a) qualitative differences exist in the sex–mortality response of medflies subjected to dietary manipulations and irradiation, …

Biodiversity And Decomposition In Experimental Grassland Ecosystems, Johannes M. H. Knops, David A. Wedin, David Tilman

School of Biological Sciences: Faculty Publications

We examined the impact of biodiversity on litter decomposition in an experiment that manipulated plant species richness. Using biomass originating from the experimental species richness gradient and from a species used as a common substrate, we measured rates of decomposition in litterbags in two locations: in situ in the experiment plots and in an adjacent common garden. This allowed us to separate the effects of litter quality and decomposition location on decomposition. We found that plant species richness had a significant, but minor negative effect on the quality (nitrogen concentration) of the biomass. Neither litter type nor location had a …