Digital Commons Network^™

Models To Predict Yield Loss Due To Weeds In Rice Ecosystems, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Yield loss models have been developed and evaluated for irrigated rice ecosystems with respect to effects of Echinochloa crusgalli. Simple regression models that give the relation between yield loss and weed density or relative leaf area are discussed with respect to their practical value in weed management in rice. More complex eco-physiological process models have been developed and used for rice ecosystems as well. Such models can be useful as a tool in research, whereas more simple approaches are needed for practical application in weed management.

Characteristics Of Modified Leghemoglobins Lsolated From Soybean (Glycine Max Merr.) Root Nodules, Hyung-Kyun Jun, Gautam Sarath, Jose F. Moran, Manuel Becana, Robert V. Klucas, Fred W. Wagner

Department of Biochemistry: Faculty Publications

Hemoprotein derivatives of an abundant soybean (Glycine max Merr.) root nodule leghemoglobin, Lba, were studied for their modified spectral characteristics and physical properties. Three modified hemoprotein derivatives of Lba (Lbam₁, Lbam₂, and Lbam₃) were purified by preparative isoelectric focusing. The ferric forms of these pigments were green and exhibited anomalous spedra in the visible region as compared to the Lba³⁺ forms. These modified pigments showed a hypochromic shift of 10 nm for the charge transfer absorption maximum; however, differences were not apparent in the Sdret region. Upon binding with nicotinate, the α …

Sequence Of A Psac Gene From The Cyanobacterium Synechococcus Sp. Pcc 6301, Patricia L. Herman, Kartika Adiwilaga, John H. Golbeck, Donald P. Weeks

Department of Biochemistry: Faculty Publications

The psaC gene encodes PsaC, the apoprotein for the terminal iron-sulfur clusters, F_A and F_B, in the PSI reaction center of cyanobacteria, algae, and higher plants. PsaC functions as a membrane-bound oxidoreductase, accepting electrons from the F_x iron-sulfur cluster located on the PsaA/PsaB heterodimer and donating them to the soluble electron transfer proteins Fd and flavodoxin (reviewed in Bryant, 1992). The objective of our work is to clarify the role of PsaC in linear and cyclic electron transfer. The experimental organism is Syneckococcus sp. PCC 6301, a unicellular, freshwater cyanobacterium that is used extensively for physiological, …

Exopeptidase Catalyzed Site-Specific Bonding Of Supports, Labels And Bioactive Agents To Proteins, Fred W. Wagner, Thomas R. Coolidge, Dwane E. Wylie, Sheldon M. Schuster, William Lewis, Jay Stout

Department of Biochemistry: Faculty Publications

The invention provides a means for attaching a label, support or bioactive agent to a protein with an exopeptidase at a site that is remote from the active site of the protein. More specifically the invention is directed to a method for the attachment of an amino acid, amine and alcohol nucleophile to the carboxyl terminus of a protein. In one embodiment, a labeled nucleophile is attached to a protein such as an antibody. In other embodiments, the invention is directed to a method for the attachment of a protein to an immobilization support and to a method for the …

Nicotinic Acid Hydroxylase From Clostridium Barkeri: Electron Paramagnetic Resonance Studies Show That Selenium Is Coordinated With Molybdenum In The Catalytically Active Selenium-Dependent Enzymenicotinic Acid Hydroxylase From Clostridium Barkeri: Electron Paramagnetic Resonance Studies Show That Selenium Is Coordinated With Molybdenum In The Catalytically Active Selenium-Dependent Enzyme, Vadim Gladyshev, Sergei V. Khangulov, Thressa C. Stadtman

Vadim Gladyshev Publications

Nicotinic acid hydroxylase from Clostidum barkeri contains selenium in an unidentified form that is dissociated as a low molecular weight compound upon denaturation of the enzyme. Other cofactors of this enzyme are molybdopterin, FAD, and iron-sulfur clusters. In the current study, we show that the enzyme, as isolated, exhibits a stable Mo(V) electron paramagnetic resonance (EPR) sal ("resting" signal) and that this signal is correlated with the selenium content and nicotinate hydroxylase activity of the enzyme. Substitution of77Se for normal selenium isotope abundance results in splitting of the Mo(V) EPR signal of the native protein without affecting the iron signals …

Experimental Evidence For Insect Impact On Populations Of Short-Lived, Perennial Plants, And Its Application In Restoration Ecology, Svata M. Louda

School of Biological Sciences: Faculty Publications

Successful management of vegetation and the restoration of threatened or endangered plant populations clearly depend on the unambiguous identification of the factors that determine and limit plant abundance and distribution (e.g. Harper 1977, Jordan, Gilpin & Aber 1987). Physical conditions, plant physiological responses, and plant competitive interactions are often important (e.g. Harper 1977, Chabot & Mooney 1985, Pickett & White 1985, Grace & Tilman 1990), and these factors are usually evaluated. However, trophic interactions, such as those involving plant consumption by insects and pathogens, may also be critical in the growth, reproduction, and population dynamics of native plants (e.g. Harper …

Purification, Characterization, And Submitochondrial Localization Of The 32-Kilodalton Nadh Dehydrogenase From Maize, Andrew F. Knudten, Jay J. Thelen, Michael Hans Luethy, Thomas Elthon

School of Biological Sciences: Faculty Publications

Plant mitochondria have the unique ability to directly oxidize exogenous NAD(P)H. We recently separated two NAD(P)H dehydrogenase activities from maize (Zea mays 1.) mitochondria using anion-exchange (Mono Q) chromatography. The first peak of activity oxidized only NADH, whereas the second oxidized both NADH and NADPH. In this paper we describe the purification of the first peak of activity to a 32-kD protein. Polyclonal antibodies to the 32-kD protein were used to show that it was present in mitochondria from several plant species. Two-dimensional gel analysis of the 32-kD NADH dehydrogenase indicated that it consisted of two major and one minor …

Characterization Of The Unique Intron - Exon Junctions Of Euglena Gene(S) Encoding The Polyprotein Precursor To The Light-Harvesting Chlorophyll A/B Binding Protein Of Photosystem Ii, Umesh Shyamsunder Muchhal, Steven D. Schwartzbach

School of Biological Sciences: Faculty Publications

The precursor to the Euglena light harvesting chlorophyll a/b binding protein of photosystem 11 (LHCPII) Is a polyprotein containing multiple copies of LHCPII covalently joined by a decapeptide linker. cDNA and genomic clones encoding the 5 and 3' end of a 6.6 kb LHCPII mRNA were sequenced. A 3.1 kb genomic region encoding 1.05 kb of the 5' end of LHCPII mRNA contains 4 introns. A 7.6 kb genomic region encoding 3.3 kb of the 3' end of LHCPII mRNA contains 10 introns. The 5' and 3' ends of the 14 Identified Euglena introns lacked the conserved dinucleotides (5'-GT and …

Enhanced Competitiveness Of Tomato Bushy Stunt Virus Defective Interfering Rnas By Segment Duplication Or Nucleotide Insertion, K. Andrew White, T. Jack Morris

School of Biological Sciences: Faculty Publications

We have analyzed atypical tomato bushy stunt virus defective interfering (DI) RNA species which accumulated during a passage series in protoplasts. We present a rationale for the order of appearance of these molecules and show, using competition assays, that either segment duplication or single nucleotide insertion can enhance DI RNA competitiveness. Possible mechanisms for the introduction of the modifications observed in these DI RNAs are discussed.

Performance Of Four Seed-Caching Corvid Species In The Radial-Arm Maze Analog, Alan Kamil, Russell P. Balda, Deborah J. Olson

Papers in Behavior in Biological Sciences

Four seed-caching corvid species were tested in an open-room analog of the radial-arm maze. During Experiment 1, the species more dependent on stored food, Clark’s nutcrackers (Nucifraga columbiana) and pinyon jays (Gymnorhinus cyanocephalus), acquired the task more quickly and to higher accuracy levels than either scrub jays (Aphelocoma coerulescens) or Mexican jays (A. ultramarina). During Experiment 2, performance after retention intervals was tested. When intervals of 30-210 min were tested in ascending order, species differences observed during acquisition were again obtained. However, when intervals of 5-300 min were tested in random order, …

Sanitation And Parasitism At Harpers Ferry, West Virginia, Karl J. Reinhard

Karl Reinhard Publications

One focus of historical archaeology at Harpers Ferry National Historical Park, West Virginia, is tracing the development of sanitation at the town through the 1800s and 1900s. Historical documentation indicates that there was a degree of resistance to the modernization of village sanitation. This study attempts to verify this resistance through examination of privy soils for parasites indicative of fecalborne disease, specifically the helminth species Ascaris lumbricoides and Trichuris trichiura. The presence of these parasites in the early 1900s would indicate that fecal-borne disease due to poor sanitation continued to be an aspect of town life. The analysis revealed the …

Otitis Media, Mastoiditis, And Infracranial Lesions In Two Plains Indian Children, Robert W. Mann, Douglas W. Owsley, Karl J. Reinhard

Karl Reinhard Publications

One disease condition that is common to nearly all children is otitis media, also known as middle ear disease. Although most people speak of it as a middle ear "infection," other causes such as neoplasm (tumor) can result in manifestations and symptoms mimicking an infectious process. This paper presents findings related to osseous lesions in two Indian children, approximately three to five years of age, who died with otitis media and infracranial lesions. Through macroscopic and radiographic analysis, it is possible to show that one child probably suffered from tuberculosis and the other from histiocytosis X. From an epidemiological and …

Trade, Contact, And Female Health In Northeast Nebraska, Karl Reinhard, Larry Tieszen, Karin L. Sandness, Lynae M. Beiningen, Elizabeth Miller, A. Mohammad Ghazi, Christiana E. Miewald, Sandra V. Barnum

Karl Reinhard Publications

Most scholars are understandably preoccupied with the impact of Europeans on native peoples who were passive, unwilling, or resistant participants in that contact. We present in this chapter a different case. The Missouri River tribes, including the Omaha and Ponca, willingly engaged in relations with Euramericans, especially in the fur trade that dominated interaction in this region. The time frame for this study is 1780- 1820, a period when interaction between individual traders and Native Americans was replaced by the dominance of the American Fur Company in organized exploitation of the Missouri River lands and peoples. This involvement later contributed …

Survey Of Cellular Radiosensitivity Parameters, Robert Katz, Rashidah Zachariah, Francis A. Cucinotta, Chunxiang Zhang

Robert Katz Publications

A model of the formation of particle tracks in emulsion has been extended through the use of biological target theory to formulate a theory of the response of biological cells and molecules of biological importance to irradiation with energetic heavy ions. For this purpose the response to γ rays is represented by the single-hit, multi-target model with parameters m and D₀, while additional parameters κ (or a₀) and σ₀ are required to represent the size of internal cellular targets and the effective cross-sectional area of the cell nucleus, respectively, for heavy-ion bombardments. For one-or-more-hit detectors, …

Ultrashort Ultraviolet Free-Electron Lasers, Donald Umstadter, L. H. Yu, E. Johnson, D. Li

Donald Umstadter Publications

In this work we combine elements of chirped pulse amplification (CPA) techniques, now familiar in solid-state lasers, with an amplifier based upon a seeded free-electron laser (FEL), The resulting device would produce amplified pulses of unprecedented brevity at wavelengths shorter than can be currently obtained by any tunable laser system. We use a subharmonically seeded FEL to illustrate the concept. Radiation from a Ti:sapphire laser is frequency-tripled and stretched optically to provide a coherent seed pulse for the FEL. When coupled to an electron beam inside a magnetic wiggler, the seed radiation introduces an additional energy modulation on the electron …

New Records Of Bolivian Mammals, Jorge A. Salazar-Bravo, Mariel Campbell, Sydney Anderson, Scott Lyell Gardner, John L. Dunnum

Harold W. Manter Laboratory of Parasitology: Faculty Publications

We present new records of occurrence and distribution for two species of didelphid marsupials and one species of echimyid rodent. Specimens were obtained from May through August 1991 and June through August 1992 in a study of mammalian diversity of Bolivia, a joint project between the Colección Boliviana de Fauna in La Paz, the Museum of Southwestern Biology (University of New Mexico), the American Museum of Natural History (New York), the Museo “Noel Kempff Mercado” de Historia Natural in Santa Cruz de la Sierra, and the University of California at Davis. This project is an attempt to strength Bolivian collections …

Fate Of Fluorescent Stained Sperm Following Insemination: New Light On Oviducal Sperm Transport And Storage In The Turkey, Murray R. Bakst

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

A novel approach was used to evaluate the distribution of sperm in the oviduct of turkey hens inseminated before or after the onset of egg production. Prior to insemination, sperm were stained with the nuclear fluorescent stain bisbenzimide. Sperm distribution in the sperm storage tubules (SST) of the uterovaginal junction and the infundibular tubular glands was determined by use of simultaneous differential interference contrast and fluorescence microscopy. In hens inseminated and examined prior to the onset of egg production, 94% of the SST contained sperm (21% were filled). In contrast, in hens inseminated initially before the onset of egg …

A Continuous Culture Of Pluripotent Fetal Hepatocytes Derived From The 8-Day Epiblast Of The Pig, Neil C. Talbot, Caird E. Rexroad Jr., Anne M. Powell, Vernon G. Pursel, Thomas J. Caperna, Sherry L. Ogg, Neil D. Nel

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

Continuous cultures of pluripotent prenchymal hepatocytes were derived from the epiblasts of 8-day-old pig blastocytes. The cells were polygonal and had phase-contrast dark, granular cytoplasm with prominent nuclei and nucleoli. These feeder-dependent cell cultures differentiated into large, multicellular, secretory, duct-like structures or formed small canaliculi between individual cells. Alternatively, the cells accumulated droplets that stained intensely with Oil Red O, a lipid-specific stain. Alpha-fetoprotein (AFP), albumin, and β-fibrinogen mRNAs were expressed as the cells differentiated in culture. Serum-free medium that was conditioned by the cells contained transferrin, AFP, and albumin. The growth and viability of the cells were inhibited by …

Life History Of Immature Maize Weevils (Coleoptera: Curculionidae) On Corn Stored At Constant Temperatures And Relative Humidities In The Laboratorv, James E. Throne

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

Life history of immature maize weevils, Sitophilus zeamais Motschulsky, was studied at 10-40°C and 43-76% RH. The optimal quantity of corn for minimizing density effects and the optimal observation frequency for minimizing disturbance effects were determined at 30°C and 75% RH. The quantity of corn (32-256 g) provided to five females ovipositing for 24 h did not affect duration of development, but the number of progeny produced increased asymptotically as the quantity of corn provided increased. Frequency of observation (from 1- to 14-d intervals) did not affect duration of development or number of progeny produced. Using moisture contents measured in …

Moisture Adsorption By Grain Protein Films, A. Gennadios, Curtis L. Weller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Grain protein films plasticized with glycerol were prepared from corn zein (CZ), wheat gluten (WG), and a 2.3:1 mixture of wheat gluten and soy protein isolate (WG/SPI). Moisture adsorption curves of the three types of protein films at 25° C and within an approximate water activity range of 0.11 to 0.84 were obtained using a static gravimetric method. The Smith, Oswin, Halsey, and Guggenheim-Anderson-de Boer (GAB) models were applied to collected data. For all protein films, the GAB model showed the best fit over the entire studied water activity range yielding mean deviation modulus values (P) of 4.69, 3.44, and …

Gamma Sigma Delta, Nebraska Chapter Newsletter, February 1994

Gamma Sigma Delta, Nebraska Chapter: Newsletters

PRESIDENT'S MESSAGE February 1994 - Dale H. Vanderholm, President, Nebraska Chapter

AT THE INTERNATIONAL LEVEL - Earl F. Ellington

NEWS FROM THE HISTORIAN - Charles H. Adams

Initiation and Awards Banquet Honored Recipients November 21, 1993

GAMMA SIGMA DELTA ACTIVITIES

GAMMA SIGMA DELTA BALFOUR PRICE LIST KEY AND PIN ORDERING INFORMATION 1994

GAMMA SIGMA DELTA 1994 COMMITTEES

Transactions Of The Nebraska Academy Of Sciences Table Of Contents: Volume 21 (1994)

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Editorial Contents

Nebraska Academy of Sciences Officers, Policy Committee ................... ii

Editorial Board ................... iv

Membership Objectives and Friends of the Academy ................... v

Nebraska Association of Teachers of Science ................... vi

Preparation of manuscripts ................... inside back cover

Papers

The limnology of three limestone rock quarries in east-central Nebraska and western Iowa (Christopher D. Mayne) ................... 1

An ordination of Niobrara Valley plant communities (Gail E. Kantak) ................... 9

Diversity of vascular plants and intensity of plant collecting in Nebraska (Robert B. Kaul and Steven B. Rolfsmeier) ................... 13

Floristic analysis of the C. Bertrand and Marian Othmer Schultz …

The Status Of Nebraska Fishes In The Missouri River, 5. Selected Chubs And Minnows (Cyprinidae): Sicklefin Chub (Macrhybopsis Meekl), Sturgeon Chub (M. Geuda), Silver Chub (M. Storeriana), Speckled Chub (M. Aestivaus), Flathead Chub (Platygobio Gracilis), Plains Minnow (Hybognathus Placitus), And Western Silvery Minnow (H. Argyritis), Larry W. Hesse

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Seven species of native Missouri River cyprinids have been reduced in abundance by 70 to 98%. Several have been extirpated from the reach upstream from Gavins Point Dam. The reasons for the decline are most likely the alteration of sediment dynamics due to dam construction, the elimination of bankful discharge, and the elimination of critical habitats, such as sandbars and off-channel areas.

The Status Of Nebraska Fishes In The Missouri River, 3. Channel Catfish (Ictaluridae: Ictalurus Punctatus), Larry W. Hesse

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The average size of Missouri River channel catfish has declined. The percentage 10 years old or older is 4.8% compared with an unexploited population in which 32% are 10 years and older. From 1944 through 1988 commercial harvest declined as much as 64%. Total mortality was 37% at age 4 and 79% at age 5. The increased mortality occurred as they reached 13 inches and became fully recruited to the commercial fishery. Harvest statistics are not wholly reliable because reports are not verifiable and commercial fishers do not return fish tags. Harvest exceeded a reasonable limit for maximum sustained yield. …

An Ordination Of Niobrara Valley Plant Communities, Gail E. Kantak

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The middle Niobrara River Valley of north-central Nebraska is of significant biogeographic importance due to the interaction of geologic and hydrologic features which provide habitat for species of eastern, western, and boreal affinities. Vegetation data collected from 10 herbaceous and 13 woody sites within the Niobrara Valley Preserve and adjacent areas were ordinated using BCORD. Results corroborate a previous literature review and TWINSPAN classification analysis which described seven major community types for this region: Sandhill, Mixed Prairie, Tallgrass Meadow, Upland Pine, Juniper, Hardwood, and Streambank Communities.

Diversity Of Vascular Plants And Intensity Of Plant Collecting In Nebraska, Robert B. Kaul, Steven B. Rolfsmeier

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

A computerized database of Nebraska's flora has been made from specimens in 20 herbaria. Almost 1,900 species of native and escaped-alien vascular plants have been collected in the state since the mid-1800s. The flora of some counties is very well known but that of many counties, especially southwestern and Sandhills counties, is poorly collected. More than 800 species (nearly 100% of the species that are likely to occur) have been collected from each of Cherry, Douglas, Lancaster, and Richardson counties, but fewer than 150 species are known from Fillmore and McPherson counties, less than 25% of the potential number species …

The Limnology Of Three Limestone Rock Quarries In East-Central Nebraska And Western Iowa, Christopher D. Mayne

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Rock-quarry lakes provide a unique environment. The aim of this study was to obtain baseline limnological data on quarries, one in Iowa and two in Nebraska, which have not been previously investigated. The results show the general limnological trends of the quarries' productivity. The mean oxygen, nutrient, pH, and phytoplankton-biomass values indicate the quarries are oligotrophic; however, one quarry has a profound depletion of oxygen in the summer and a large seasonal variation in alkalinity. A higher nitrogen concentration as well as more littoral plants suggests it to have more eutrophic potential than the other two quarries. Metal-ion analysis shows …

Morphometry Of Growth In Hatchling Striped Plateau Lizards (Iguanidae: Sceloporus Virgatus), Geoffrey R. Smith

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

I studied the ontogenetic development of body shape and the influence of food availability on the development of body shape in hatchling striped plateau lizards (Sceloporus virgatus) over the first seven to eight weeks of their life. Body mass showed positive growth relative to snout-vent length. Head width, head length, and femur length showed negative growth relative to snout-vent length. No sexual differences were evident in relative growth in any body part or trait. Food availability did not influence the relative growth of body parts or traits.

Notes On The Biology And A Description Of The Egg, Third Instar Larva And Pupa Of Neobisnius Sobrinus (Coleoptera: Staphylinidae), Daniel A. Schmidt

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The egg, third instar larva and pupa of Neobisnius sobrinus (Erichson) are described and illustrations of structural features are provided. Both adults and larvae are cryptic and hygrophilous, living in moist organic debris along streams and ponds. The species appears to have a polyvoltine life cycle. Larval-rearing techniques are described and data presented on growth of immatures. This first detailed description of any Neobisnius larva indicates that the genus differs from related genera in having three stemmata on each side of the head, a mandible with seriations on the inner margin, and sharp cuticular spines on the inner surface ofthe …

Nectar-Seeking Visits By Butterflies In A Tallgrass Prairie Remnant In Eastern Nebraska, Tanya Bray

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Stolley Prairie, a tallgrass virgin prairie remnant in eastern Nebraska, was visited 20 times between May 25 and August 14, 1988. Fifty-two species of forbs were observed in bloom during this period. Twenty-seven species of butterflies were observed and 21 species made 262 nectar-seeking visits to 21 plant species. While numbers of forbs in bloom did not strongly correlate with numbers of butterflies present, peaks of butterfly occurrence appeared to follow peaks of blossom abundance. The number of plant species utilized by a species of butterfly ranged from one to nine. Plants with an abundance of nectar such as common …