Digital Commons Network^™

Deletion Of The Δ12-Oleic Acid Desaturase Gene Of A Nonaflatoxigenic Aspergillus Parasiticus Field Isolate Affects Conidiation And Sclerotial Development, Perng Kuang Chang, Richard A. Wilson, Nancy P. Keller, Thomas E. Cleveland

Fungal Molecular Plant-Microbe Interactions

Aims: To investigate how linoleic acid affects conidial production and sclerotial development in a strictly mitotic Aspergillus parasiticus field isolate as related to improving biocompetitivity of atoxigenic Aspergillus species.

Methods and Results: We disrupted A. parasiticus Δ12-oleic acid desaturase gene (odeA) responsible for the conversion of oleic acid to linoleic acid. We examined conidiation and sclerotial development of SRRC 2043 and three isogenic mutant strains deleted for the odeA gene (DodeA), either with or without supplementing linoleic acid, on one complex potato dextrose agar (PDA) medium and on two defined media: nitrate-containing Czapek agar (CZ) and Cove’s ammonium …

Characterization Of The Aspergillus Parasiticus Δ12-Desaturase Gene: A Role For Lipid Metabolism In The Aspergillus–Seed Interaction, Richard A. Wilson, Ana M. Calvo, Perng-Kuang Chang, Nancy P. Keller

Fungal Molecular Plant-Microbe Interactions

In the mycotoxigenic oilseed pathogens Aspergillus flavus and Aspergillus parasiticus and the model filamentous fungus Aspergillus nidulans, unsaturated fatty acids and their derivatives act as important developmental signals that affect asexual conidiospore, sexual ascospore and/or sclerotial development. To dissect the relationship between lipid metabolism and fungal development, an A. parasiticus Δ¹²-desaturase mutant that was unable to convert oleic acid to linoleic acid and was thus impaired in polyunsaturated fatty acid biosynthesis was generated. The Δ¹²-desaturase mutant demonstrates delayed spore germination, a twofold reduction in growth, a reduced level of conidiation and complete loss of sclerotial …

Two Δ9-Stearic Acid Desaturases Are Required For Aspergillus Nidulans Growth And Development, Richard A. Wilson, Perng-Kuang Chang, Agnieszka Dobrzyn, James B. Ntambi, Robert Zarnowski, Nancy P. Keller

Fungal Molecular Plant-Microbe Interactions

Unsaturated fatty acids are important constituents of all cell membranes and are required for normal growth. In the filamentous fungus Aspergillus nidulans, unsaturated fatty acids and their derivatives also influence asexual (conidial) and sexual (ascospore) sporulation processes. To investigate the relationship between fatty acid metabolism and fungal development, we disrupted the A. nidulans sdeA and sdeB genes, both encoding Δ9-stearic acid desaturases responsible for the conversion of palmitic acid (16:0) and stearic acid (18:0) to palmitoleic acid (16:1) and oleic acid (18:1). The effects of sdeA deletion on development were profound, such that growth, conidial and ascospore production were …

Carbon Dioxide Dynamics During A Growing Season In Midwestern Cropping Systems, J. H. Prueger, J. L. Hatfield, T. B. Parkin, W.P. Kustas, T. C. Kaspar

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

Daily and seasonal CO₂-exchange dynamics between the boundary layer and biosphere is important to understanding Net Ecosystem Exchange of terrestrial ecosystems. Spatial and temporal variations of CO₂ fluxes across midwestern cropping systems have not been well documented. This study was designed to monitor and evaluate spatial and temporal dynamics of CO₂ exchange across a watershed region for typical production fields of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] in the Midwest by quantifying the above-canopy, within-canopy, and soil components of C balance for this cropping system. An energy-balance approach using eddy …

Water Quality And The Grazing Animal, R. K. Hubbard, G. L. Newton, G. M. Hill

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

Grazing animals and pasture production can affect water quality both positively and negatively. Good management practices for forage production protect the soil surface from erosion compared with conventionally produced crops. Grazing animals and pasture production can negatively affect water quality through erosion and sediment transport into surface waters, through nutrients from urine and feces dropped by the animals and fertility practices associated with production of high-quality pasture, and through pathogens from the wastes. Erosion and sediment transport is primarily associated with high-density stocking and/ or poor forage stands. The two nutrients of primary concern relating to animal production are N …

Evaluation Of Adapted Wheat Cultivars For Tolerance To Pythium Root Rot, R. W. Higginbotham, T. C. Paulitz, K. A. Garland-Campbell, K. K. Kidwell

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

Genetic resistance in wheat (Triticum aestivum) against Pythium species would be an efficient means of control of this major root fungal pathogen, but so far no source has been identified. In addition, no long-term, sustainable options for controlling Pythium root rot are available; therefore, identifying and then incorporating genetic resistance into wheat cultivars would create an ideal method of control for this disease. The objective of this study was to examine the level of tolerance to Pythium root rot among a diverse set of wheat germ plasm collected from all major wheat production regions in the United States.

Betaine Improves Growth, But Does Not Induce Whole Body Or Hepatic Palmitate Oxidation In Swine (Sus Scrofa Domestica), Diane Wray-Cahen, Ignacio Fernández-Fígares, Erkki Virtanen, Norman C. Steele, Thomas J. Caperna

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

Dietary betaine may reduce carcass fat in growing pigs. We explored the effects of betaine on short-term growth and in vivo and in vitro fatty acid oxidation. Pigs were housed in metabolism crates and fed diets containing either 0% (control), 0.125% or 0.5% betaine at 80% of ad libitum energy intake. Fatty acid oxidation was measured during intravenous infusions of 1-¹³C-palmitate and in hepatocytes incubated in the presence or absence of betaine and carnitine. CO₂ and palmitate isotopic enrichments were determined by mass spectrometry. Pigs consuming 0.125% and 0.5% betaine for at least 9 days had growth …

Case Study: Effects Of Delaying Implant And Programmed Rate Of Gain On Performance And Carcass Characteristics Of Yearling Beef Steers, G. Scaglia, L. W. Greene, F. T. Mccollum, N. A. Cole, T. H. Montgomery

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

Ninety-six steers (average BW = 335 ± 36 kg) were allotted in a completely randomized design with a 2 × 2 factorial arrangement of treatments. Factors were 1) implant on d 1 or no implant and 2) ad libitum access to feed on d 1 or programmed-fed for a target BW gain of 1.4 kg/d during the first 62 d of the feeding period. On d 63, all steers were implanted with Revalor-S^® (Hoechst Roussel Vet, Overland Park, KS) and provided ad libitum access to feed until harvest. From d 63 to 116, ADG and gain efficiency (g gain/kg …

Performance And Carcass Characteristics Of Feedlot Steers: Effects Of Delayed Implanting And Programmed Feeding During The Growing Period, G. Scaglia, L. W. Greene, F. T. Mccollum Iii, N. A. Cole, T. H. Montgomery

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

This experiment was conducted to determine the effect of programming the rate of gain and delaying the first implant in feedlot steers on feedlot performance and carcass characteristics. Ninety-six growing steers (269 ± 16.2 kg) were assigned to 12 pens in a completely randomized design. Treatments were implant (Synovex-S^®; 20 mg estradiol benzoate and 200 mg progesterone; Fort Dodge Animal Health, Overland Park, KS) on d 1 or no implant and programmed feeding to gain at a slow (0.68 kg/d) or fast (1.14 kg/d) rate during the growing period; these treatments were randomly assigned (n = 8) to …

Somatic Mutation-Mediated Evolution Of Herbicide Resistance In The Nonindigenous Invasive Plant Hydrilla (Hydrilla Verticillata) And Franck E. Dayan, Albrecht Michel, R. S. Arias, Brian E. Scheffler, Stephen O. Duke, Michael Netherland, Franck E. Dayan

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

Hydrilla (Hydrilla verticillata L.f. Royle) was introduced to the surface water of Florida in the 1950s and is today one of the most serious aquatic weed problems in the USA. As a result of concerns associated with the applications of pesticides to aquatic systems, fluridone is the only USEPA-approved chemical that provides systemic control of hydrilla. After a decrease in fluridone’s efficacy at controlling hydrilla, 200 Florida water bodies were sampled to determine the extent of the problem and the biological basis for the reduced efficacy. Our studies revealed that hydrilla phenotypes with two- to six-fold higher fluridone resistance …

Putting Genes Into Genetic Coefficients, P. Stephen Baenziger, Gregory S. Mcmaster, Wallace Wilhelm, Albert Weiss

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

Plant parameters are critical inputs in crop simulation models and allow a general set of algorithms to represent features of specific cultivars. A subset of plant parameters is often referred to as "genetic coefficients". However, these genetic coefficients are developed from phenotypic observations, usually have a weak genetic basis, and are at best "genotypic" coefficients because they consider the genotype from a very integrative perspective and likely include some impact of environment on the trait or characteristic described. With increased understanding of crop genomes, we believe models can be improved by incorporating genetic coefficients that accurately describe the action of …

Ecological Species Groups Of South Carolina's Jocassee Gorges, Southern Appalachian Mountains, Scott R. Abella, Victor B. Shelburne

Public Policy and Leadership Faculty Research

Ecological species groups, consisting of assemblages of co-occurring plant species exhibiting similar environmental affinities, were developed for ground-flora and tree strata in late- successional forests on a 13,000 ha southern Appalachian landscape. We distinguished 11 ground-flora groups that included 50 species and six tree groups comprised of 19 species. Ground-flora groups ranged from a xeric Vaccinium group (including Vaccinium pallidum, Euphorbia corollata, and Piptochaetium avenaceum) to a mesic Rhododendron group (typified by Rhododendron maximum, Mitchella repens, and Hexastylis heterophylla). Tree groups ranged from a Quercus coccinea group to a Tsuga canadensis group. Consistent with previous research, species groups exhibited a …

Ecology Of Eastern Prickly Pear Cactus (Opuntia Humifusa) In Oak Openings Preserve, Northwestern Ohio, Scott R. Abella, John F. Jaeger

Public Policy and Leadership Faculty Research

Opuntia humifusa (eastern prickly pear cactus) is listed as potentially threatened in Ohio, and we examined the characteristics of O. humifusa sites in Oak Openings Preserve in northwestern Ohio’s Oak Openings region in an attempt to provide data that may help protect this species. Opuntia humifusa occurrences were associated with loose sands of the xeric Udipsamment Ottokee and Oakville soil series on sites that had been cleared before the 1940s during failed agricultural attempts. Shading by encroaching canopy trees is a threat to several O. humifusa populations in Oak Openings Preserve, and treatments that reduce canopy cover at these sites …

Tree Thinning And Prescribed Burning Effects On Ground Flora In Arizona Ponderosa Pine Forests: A Review, Scott R. Abella

Public Policy and Leadership Faculty Research

Ground flora is an important response variable to monitor after tree thinning and prescribed burning treatments designed to restore Arizona ponderosa pine (Pinus ponderosa P.& C. Lawson) forests. This paper reviews published literature on the effects of thinning and burning on ground flora in Arizona ponderosa pine forests in five main categories of research: ground flora biomass, species diversity, plant community composition, population processes, and individual species ecology. Research published to date suggests that thinning and burning generally increase ground flora biomass, whereas other categories of research such as community composition and population processes have been little studied in Arizona …

Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Accurate prediction of phenological development is important in the winter wheat Triticum aestivum agroecosystem. From a practical perspective, applications of pesticides and fertilizers are carried out at specific phenological stages. In crop-simulation modeling, the prediction of yield components (kernel number and kernel weight) and wheat-grain yield relies on accurate prediction of phenology. In this study, a nonlinear multiplicative model by Wang & Engel (WE) for predicting phenological development in differing winter wheat cultivars was evaluated using data from a 3 yr field experiment. In the vegetative phase (emergence to anthesis) the daily development rate (r) was simulated based on the …

An Investigation Of Weed Pest Problems In The Emerging Foliage Industry In Kerry, Tom Houlihan

Theses

The rapidly expanding cut foliage industry in the southwest of Ireland aims to satisfy the demands of an exacting market requiring quality stems for use in the manufacture of flower and foliage bouquets.

The studies identified, in detail, the type of weed pests that cause problems for growers of cultivated foliage crops and examined current weed control practice. Residual herbicides with potential for use within the sector were screened and trials were set up in a number of important foliage species.

Recommendations on weed management regimes based on the findings from these trials and economic criteria are presented for Paeony …

A Guide To Growing Healthy Trees In The Lower Rio Grande Valley, Valley Proud Environmental Council, Texas Forest Service, Texas Urban Forestry Council, Brownsville Public Utilities Board, Brownsville Beautification Committee, Joe Ideker, Steve Benn, Beau Hollingsworth, Chris Best, Robert I. Lonard

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

No abstract provided.

Phylogeny And Biogeography Of Wajira (Leguminosae): A Monophyletic Segregate Of Vigna Centered In The Horn Of Africa Region, Mats Thulin, Matt Lavin, Remy Pasquet, Alfonso Delgado-Salinas

All Peer-Reviewed Publications

Evidence from chloroplast trnK and nuclear ribosomal ITS sequences and morphological data reveals that the monotypic legume genus Wajira is nested within a clade comprising the species of Vigna subgen. Macrorhynchus. This Wajira-containing clade is basally branching in a larger clade that contains many of the genera traditionally referred to as tribe Phaseoleae subtribe Phaseolinae. Wajira is thus recircumscribed to include Vigna subgen. Macrorhynchus. Given the heterogeneity of floral morphology of its constituent species, Wajira is apomorphically diagnosed by woody stems and a pollen brush that comprises an introrse linear array of unicellular hairs. This recircumscribed genus now comprises five …

Correlation Between Atmospheric Co2 Concentration And Vegetation Greenness In North America: Co2 Fertilization Effect, C. Lim, Menas Kafatos, P. Megonigal

Mathematics, Physics, and Computer Science Faculty Articles and Research

The possibility that rising atmospheric CO2 concentrations are influencing plant growth in contemporary ecosystems has received little attention, and the studies that exist have been done on a small spatial scale. We correlated the monthly rate of relative change in normalized differenced vegetation index (NDVI) from advanced very high resolution radiometer (AVHRR) data to the rate of change in atmospheric CO2 concentration during the natural vegetation growing season for evidence of a possible CO2 fertilization effect on vegetation development. The study addressed seasonal and annual patterns in spatially averaged NDVI for 3 different ecological regions in North America from 1982 …

Recent Developments In International Biological Nomenclature, Werner Greuter

Turkish Journal of Botany

After a period of several decades of general neglect, biological systematics and taxonomy are again surfacing to the awareness of the scientific community and of policy makers. This we owe to the fact that they are the core disciplines of biodiversity research, now perceived to be a priority task in view of the impending threat of loss through extinction of a great number of species, and the wholesale destruction of ecosystems. Yet the renaissance of systematics and taxonomy is hampered by the inadequacy of the traditional rules governing the formation and use of scientific names of organisms. Names are a …

Biology Of The Central Desert Of Oman, Shahina A. Ghazanfar

Turkish Journal of Botany

A biological survey of the central desert of Oman was done using long distance transects. Vegetation was sparse and consisted of 200+ plant species, 22 species of mammals, 17 species of reptiles and amphibians, and more than 50 species of birds (migratory and resident). Three main vegetation types were identified based on ground substrate and the dominance of species. These were communities with Acacia Willd., Zygophyllum L., and open woodlands of Prosopis cineraria (L.) Druce. Over-grazing and development in the central desert has led to concerns over the conservation of the desert ecosystem in Oman.

Supplemental Forms Of Intellectual Property Protection For Plants, Mark D. Janis

Articles by Maurer Faculty

A new hierarchy of intellectual property protection for plant innovation is emerging. Utility patent protection is poised to become the dominant intellectual property mechanism for plants in the U.S. and perhaps elsewhere. Plant breeder's rights systems continue to garner a dedicated following, especially in developing countries, as a means for complying with international intellectual property treaty obligations. But while utility patent and plant breeder's rights regimes have come to occupy the first tier of the intellectual property hierarchy for plants, other forms of intellectual property protection remain important, albeit in a supplemental role. This article surveys supplemental intellectual property strategies …

Sexual And Asexual Reproductive Characteristics Of The North American Pawpaw [Asimina Triloba (L.) Dunal], Sheri Beth Crabtree

University of Kentucky Master's Theses

The North American Pawpaw [Asimina triloba (L.) Dunal] shows great potential as a new fruit crop. Kentucky State University in Frankfort, Ky. is the site for the USDA National Clonal Germplasm Repository (NCGR) for Asimina species. Both the fruit and the trees themselves are of high value to growers and nursery producers. Pawpaw cultivars are currently propagated by grafting or budding onto seedling rootstock; no method currently exists to clonally propagate pawpaw on its own roots. Three methods of layering were attempted in this study to clonally propagate pawpaw: trench layering, pot layering, and mound layering. Both trench layering …

Loline Alkaloid Biosynthesis In Neotyphodium Uncinatum, A Fungal Endophyte Of Lolium Pratense, Jimmy Douglas Blankenship

University of Kentucky Doctoral Dissertations

Some endophytes in mutualistic associations with Festuca, Lolium and other grass species produce insecticidal loline alkaloids (1-aminopyrrolizidines; LA). These loline alkaloids have a saturated pyrrolizidine ring system (two-rings sharing a carbon and nitrogen atom), a 1-amine substituted with methyl, acetyl, or formyl groups, and an oxygen bridge between C-2 and C-7. The development of a reliable system of production of LA in cultures of the Lolium pratense (meadow fescue) endophyte, Neotyphodium uncinatum, facilitated work on the LA biosynthetic pathway. N. uncinatum produced norloline, loline, methylloline, N-acetylnorloline (NANL), N-formylloline (NFL), and N-acetylloline as detected in culture filtrates. The total production …

Tissue Culture And Transformation Of Introducing Genes Useful For Pest Management In Rice, Shuli Zhang

LSU Doctoral Dissertations

Sheath blight (SB), caused by Rhizoctonia solani K¨¹hn, is a major rice disease internationally and in the southern rice area of the Unites States, including Louisiana. Breeders have incorporated partial resistance into commercial rice varieties to control the disease, but a higher level of resistance is needed. It has been demonstrated that the pathogenesis-related (PR) proteins ¦Â-1, 3-glucanase and chitinase are components of effective defense mechanisms for protecting plants against fungal pathogens. This research was conducted to co-transform the ¦Â-1, 3-glucanase, chitinase and bar genes into the rice variety Taipei 309 using the hpt gene for resistance to hygromycin B …

Concentrations Of Metals In River Sediment And Wetland Vegetations In Mining, Lake Victoria Basin, Tanzania, Jf Machiwa

Tanzania Journal of Science

Levels of metals were determined in river sediment, rice and sugarcane juice from Lake Victoria basin where small-scale gold processing activities are carried out to assess levels of contamination. Concentrations of metals in river sediments were generally high in areas that were closest to gold ore processing sites. For instance, mercury was highest (36.3 ±12.8 mg/g dw) in river sediments of Tigiti River in Mugumu District. Other heavy metals (Cd, Pb, Zn and Cu) had highest concentrations (2.20±0.71, 208±19.3, 412±20.1 and 132.7±11.9mg/g dw, respectively) in sediment samples from Kagota. The concentration of arsenic was highest (985.0±67.2 mg/g dw) in Mugusu …

Insect Infestation Of Maize, Zea Mays (L.) In Indigenous Storage Structures In Morogoro Region, Tanzania, Cp Rugumamu

Tanzania Journal of Science

Insect infestations and losses of maize stored in four types of indigenous storage structures in Morogoro Region, Tanzania were investigated. Infestation levels and weight losses caused by the larger grain borer, Prostephanus truncatus (Horn) and the maize weevil, Sitophilus zeamais (Motsch.) were found to differ significantly in the four types of storage structures (Dari, Kihenge, Kichanja and Reli). Lower infestation levels by the two pests and less weight losses were observed inDari and Kihenge than in Kichanja and Reli. The infestations and weight losses exhibited a significant trend that was in the order, Dari< Kihenge < Kichanja < Reli. These findings suggest that Dari and Kihenge are more appropriate for the incorporation in Integrated Pest Management (IPM) for P. truncatus and S. zeamais in Morogoro Region.

Soil Organic Carbon Content And Composition Of 130-Year Crop, Pasture And Forest Land-Use Managements, Dean A. Martens, Thomas E. Reedy, David T. Lewis (Retired)

Department of Agronomy and Horticulture: Faculty Publications

Conversion of former agricultural land to grassland and forest ecosystems is a suggested option for mitigation of increased atmospheric CO₂. A Sharpsburg prairie loess soil (fine, smectitic, mesic Typic Argiudoll) provided treatments to study the impact of long-term land use on soil organic carbon (SOC) content and composition for a 130-year-old cropped, pasture and forest comparison. The forest and pasture land use significantly retained more SOC, 46% and 25%, respectively, compared with cropped land use, and forest land use increased soil C content by 29% compared with the pasture. Organic C retained in the soils was a function …

Center For Grassland Studies Newsletter, Winter 2003, Volume 9, No. 1

Center for Grassland Studies: Newsletters

Planning for Bison Grazing on Native Rangeland by Kristin Miller, USDA Natural Resources Conservation Service

Pooled Sales Add Value to Cull Cows by Rebekka Martin and Jana Beckman

The Grass Dance

UNL Offers Online Course in Turf Diseases

Second National Conference on Grazing Lands

Seed Dormancy – the Uncertainty in Native Grass Seeding

Prairie Pines to Benefit UNL Programs by Steven Ress, Water Center, UNL

Platte River Trust Begins Study of Birds Breeding in Grasslands by Felipe Chavez-Ramirez, Platte River Whooping Crane Maintenance Trust

Nectar Rewards Of Insect-Adapted Flowers In A Forest/Farm Landscape: Measurement Challenges And Ecological Questions, Theresa Bordenkecher Dailey

All-Inclusive List of Electronic Theses and Dissertations

Native forest wildflowers of the Midwestern United States forests now compete with agricultural weeds for the attention of insect pollinators. The tiny quantities of nectar secreted by these insect-pollinated flowers are measured using laboratory techniques such as colorimetry. However, these techniques are used with the tacit assumption that nectar sugar identity does not affect estimates of carbohydrate content. I tested this hypothesis using fructose, glucose, and sucrose and found that after reaction with anthrone, fructose products differed from those of other sugars in light absorbance measured by a spectrophotometer. Potential error from using an inappropriate sugar standard is greater than …