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Fungal Antigens and Fungal Disease: An Alkali-Soluble, Water Soluble Antigen from Coccidioides immitis and Coccidioidomycosis

Description: Diagnostic medical mycology has been slow to advance due to a lack of species specific antigens in organisms which cause serious diseases in man. Toward this end, an HPLC analysis was done of the following fungal antigens: histoplasmins HKC-43 and H-42, blastomycin KCB-26, an alkali-soluble, water soluble antigen from Blastomyces dermatitidis (b-ASWS), a coccidioidin prepared from a toluene lysate of the mycelial-arthroconidia phase of Coccidioides immitis, and an alkali-soluble, water-soluble antigen from Coccidioides immitis (c-ASWS). The HPLC survey included size-exclusion chromatography (SEC), ion exchange chromatography (HPIEC), and reversephase chromatography (RP). Resolution was poor with both SEC and HPIEC but was excellent with RP chromatography. The use of RP will allow sufficient separation for further antigenic and structural analysis.
Date: December 1983
Creator: Fleming, William H. (William Harold)
Partner: UNT Libraries

Comparative Ecology of Benthic Communities in Natural and Regulated Areas of the Flathead and Kootenai Rivers, Montana

Description: A comparative study was made of environmental variables and the density, biomass, diversity, and species composition of macroinvertebrates in areas downstream from a dam with a hypolimnetic release (Hungry Horse Dam on the Flathead River) and a dam with a selective withdrawal system (Libby Dam on the Kootenai River). A major objective of this study was to examine the response of macroinvertebrate communities to defined environmental gradients in temperature, flow, substrate, and food-related variables (periphyton, particulate organic carbon in the seston). In addition, the effects of experimental manipulations in discharge on macroinvertebrate drift and stranding were assessed, and the effects of temperature on the growth rates and emergence of five species of insects were measured.
Date: May 1984
Creator: Perry, Sue A.
Partner: UNT Libraries

Studies on the Drumming Behavior of North American Stoneflies (Plecoptera)

Description: Drumming behavior is described for the first time in 16 North American species of Plecoptera, and signals of a 17th species, Isogenoides zionensis, are further detailed. The effective distance over which drumming signals may be transmitted was tested for four communication modes. Results indicate that substratum vibrations are far superior to sound in the transmission of drumming signals, and that dense substrates such as rocks are poor channels for signal transfer. Long communication periods between stonefly pairs of Taeniopteryx burksi resulted in some alterations from initial signaling characteristics.
Date: May 1984
Creator: Zeigler, David D.
Partner: UNT Libraries

Genetic and Morphological Variation in Natural Populations of the Red Shiner, Notropis lutrensis, and their Relationship to Adaptation in a Generalist Species

Description: Twenty-two natural populations of the red shiner minnow, Notropis lutrensis were examined for morphological and genetic variation. This research was aimed at testing the hypothesis that morphological and genetic variation was primarily influenced by the degree of gene flow between populations. Ten linear measurements were taken from each of 1320 specimens. Morphological characters were adjusted for differential growth by least squares linear regression techniques. Genetic variability was estimated for each individual red shiner through the methods of starch gel electrophoresis. Twenty presumtive gene loci were resolved.
Date: May 1984
Creator: Wooten, Michael Conrad
Partner: UNT Libraries

9-Lipoxygenase Oxylipin Pathway in Plant Response to Biotic Stress

Description: The activity of plant 9-lipoxygenases (LOXs) influences the outcome of Arabidopsis thaliana interaction with pathogen and insects. Evidence provided here indicates that in Arabidopsis, 9-LOXs facilitate infestation by Myzus persicae, commonly known as the green peach aphid (GPA), a sap-sucking insect, and infection by the fungal pathogen Fusarium graminearum. in comparison to the wild-type plant, lox5 mutants, which are deficient in a 9-lipoxygenase, GPA population was smaller and the insect spent less time feeding from sieve elements and xylem, thus resulting in reduced water content and fecundity of GPA. LOX5 expression is induced rapidly in roots of GPA-infested plants. This increase in LOX5 expression is paralleled by an increase in LOX5-synthesized oxylipins in the root and petiole exudates of GPA-infested plants. Micrografting experiments demonstrated that GPA population size was smaller on plants in which the roots were of the lox5 mutant genotype. Exogenous treatment of lox5 mutant roots with 9-hydroxyoctadecanoic acid restored water content and population size of GPA on lox5 mutants. Together, these results suggest that LOX5 genotype in roots is critical for facilitating insect infestation of Arabidopsis. in Arabidopsis, 9-LOX function is also required for facilitating infection by F. graminearum, which is a leading cause of Fusarium head blight (FHB) disease in wheat and other small grain crops. Loss of LOX1 and LOX5 function resulted in enhanced resistance to F. graminearum infection. Similarly in wheat, RNA interference mediated silencing of the 9-LOX homolog TaLpx1, resulted in enhanced resistance to F. graminearum. Experiments in Arabidopsis indicate that 9-LOXs promote susceptibility to this fungus by suppressing the activation of salicylic acid-mediated defense responses that are important for basal resistance to this fungus. the lox1 and lox5 mutants were also compromised for systemic acquired resistance (SAR), an inducible defense mechanism that is systemically activated throughout a plant in response to a ...
Date: May 2012
Creator: Nalam, Vamsi J.
Partner: UNT Libraries

Size Fractionation of Metabolically Active Phytoplankton and Bacteria in Two Diverse Lentic Systems

Description: Simultaneous size fractionation of plankton populations associated with NaH^14CO_3 and ^3H-glucose uptake was employed in eutrophic Lake Texoma (Texas and Oklahoma) and oligotrophic Flathead Lake (Montana). Autoradiography was utilized to determine the role of specific microorganisms in community metabolism. Ultraplankton (0.45-10 μm) dominated plankton numbers and metabolic activity in both aquatic systems. Many of the most abundant species were not the most productive, in terms of inorganic C fixation. Rates of heterotrophic uptake of ^3H-glucose were small in comparison to photolithotrophic uptake in both lakes, Photoheterotrophy was more extensive in Flathead Lake, Autoradiographs indicated that bacteria were responsible for observed photoheterotrophy. Oscillatoria sp. exhibited. mixotrophy in Lake Texoma,
Date: August 1980
Creator: Ellis, Bonnie K.
Partner: UNT Libraries

Effects of Water Source, Suspended Solids, and Acclimation on Biotransformation of 2 /4-Dichlorophenoxy Acetic Acid in Aquatic Systems

Description: In recent years there has been a great deal of scientific interest in processes that affect the fate of organic chemicals in the environment. one main reason for this increased interest is due to greater environmental concern over accidental or purposeful release of these chemicals into the environment by man. A major environmental concern is the increased use of pesticides over the last few years. In the thirty years prior to 1978 the use of pesticides has increased by a factor of forty (Ridgeway et al., 1978). Recently the use of herbicides has been increasing, but that of insecticides has stabilized (Willis, 1983). Detectable amounts of organic pesticides can be found in many areas of the biosphere. For toxic organic chemicals to be used safely, researchers must have a clear understanding of the fate and persistence of these chemicals when they are released into the environment. This understanding will also allow the development of new products that, when properly used, will not produce adverse effects to man or the environment (Weber, 1972). According to the Toxic Substance Control Act (TSCA) any new or expanded-use chemical that might be released into the environment must be tested for environmental hazard.
Date: August 1985
Creator: Moses, Christopher K. (Christopher Karam)
Partner: UNT Libraries

Passive Dispersal of Algae and Protozoa Internally and Externally by Selected Aquatic Insects

Description: This investigation was concerned with three aspects of the problem of passive dispersal of algae and protozoa by aquatic insects: the role of odonates in passive dispersal of viable small aquatic organisms, the passage of viable algae and protozoa through digestive tracts of field-collected herbivorous and carnivorous aquatic insects, and the viability duration of selected algae, during insect transport under monitored conditions.
Date: December 1970
Creator: Solon, Bernard M. (Bernard Michael), 1932-
Partner: UNT Libraries

Ecological Association Between the Red-Cockaded Woodpecker and Southern Pine Beetle in the Homochitto National Forest: a Geographic Information System Approach

Description: Since the introduction of management practices by the Forest Service to stabilize red-cockaded woodpecker (RCW) populations, the number of cavity trees killed by southern pine beetles (SPB) has increased. A model of the landscape ecology of RCW and SPB in the Homochitto National Forest was created using data collected from the Forest Service and Global Atmospherics. The conclusions of the study were that the RCW and SPB utilize the same type of habitat and the stand hazard maps are an accurate means of determining the locations of SPB infestations. The functional heterogeneity maps created for the SPB and RCW would be useful predictors of future occurrences of either species if complete data were obtained.
Date: December 1998
Creator: Skordinski, Karen R. (Karen Renee)
Partner: UNT Libraries

Advanced Molecular and Microbial Techniques: a Complete Laboratory Notebook

Description: The purpose of this project is to produce a complete and thorough notebook that may be used to supplement laboratory coursework. Its intent is to be used primarily by the students to aid them in understanding background information and the proper laboratory procedures involved in various types of experiments. The laboratory notebook is a summation of all the experiments and procedures used in the six-credit hour Advanced Microbial and Molecular Biology (BIOL 5160) course offered during the summer semester at the University of North Texas. This class is a team taught effort by Professors O'Donovan and Kunz. The course is constructed as an intensive practice exercise to teach the student about gene mutations, biosynthetic pathways, preparation and analysis of plasmid DNA, and many other topics included in the notebook.
Date: May 1998
Creator: Brito-Rodriquez, Carmen Lydia
Partner: UNT Libraries

Pretreatment Optimization of Fiberglass Manufacturing Industrial Wastewater

Description: Wastewater effluent produced in the fiberglass manufacturing industry contains a significant amount of total suspended solids. Environmental regulations require pretreatment of effluent before it is discharged to the municipal wastewater treatment plant. Chemical precipitation by coagulation and flocculation is the method of pretreatment used at the Vetrotex CertainTeed Corporation (VCT). A treatability study was conducted to determine conditions at which the VCT Wastewater Pretreatment Plant could operate to consistently achieve a total suspended solids concentration ≤ 200-mg/L. Jar tests varied pH, polymer dosage, and ferric sulfate dosage. Total suspended solids and turbidity were measured to evaluate treatment performance. The data were used to determine an optimum set of conditions under project guidelines. Of twelve polymers screened, BPL 594 was selected as the most effective polymer. For cost efficiency in the wastewater pretreatment operation, recommendations suggested that treatment chemical injection be electronically controlled according to turbidity of the treated effluent.
Date: December 1998
Creator: Dragoo, Ron
Partner: UNT Libraries

Response of Freshwater and Saltwater Toxicity Test Species to Calcium and Salinity Concentrations Encountered in Toxicity Tests

Description: The responses of freshwater (Daphnia magna. Pimephales promelas) and saltwater (Mysidopsis bahia. Cyprinodon variegatus) toxicity test species to elevated calcium concentrations and changing salinity conditions were investigated. The use of salinity as a criterion for selection between saltwater and freshwater test species was investigated by conducting both calcium and salinity toxicity tests. Salinity was determined to be an inappropriate criterion under conditions encountered in this study.
Date: 1989
Creator: Price, Edmund E., 1954-
Partner: UNT Libraries

Factors Inhibiting Dissociation Of Neisseria gonorrhoeae Cells

Description: The initial studies reported in this dissertation were attempts to induce mutations in those genes which control dissociation in cells of Nei sseria gonorrhoeae. These studies led to an investigation of survival curves of cells grown in liquid media. Instead of survival curves reflecting the diploid nature of gonococci, multiple cell kinetics were observed. It was found that large clumps contained a predominance of cells of the T2 type and that when these clumps were dispersed by DNAase, it appeared that dissociation of T2 was inhibited. The notion of a mechanism of T2 to T4 dissociation being due to genetic transformation was disspelled by these data.
Date: August 1982
Creator: Gonzalez, Anthony H.
Partner: UNT Libraries

Degradation of Humic Substances by Aquatic Bacteria

Description: A variety of aquatic bacteria were isolated and tested for their ability to degrade humic substances and their aromatic residues/monomers which serve as precursors of the trihalomethanes (THMs) found in chlorinated drinking waters. The majority of them were Gram-negative, oxidative types dominated by pseudomonads. Most of the 146 isolates were found to utilize as their sole source of carbon several or more of ten aromatic compounds known to be products of degradation of humus and also to be precursors of THMs. The aromatics tested, with percent of the isolates utilizing the compound in parentheses, were: p-hydroxybenzoate (49), vanillic acid (48), 3,5-dihydroxybenzoic acid (16), syringic acid (19), vanillin (30), benzoic acid (27), ferulic acid (34), resorcinol (9), catechol (8) and protocatechuic acid (27).
Date: August 1985
Creator: Baiu, Saleh Hamed Salem
Partner: UNT Libraries

Testing and Evaluation of Environmental Fate Models Using Aquatic Microcosms and Three Organic Chemicals

Description: Two compartment (sediment and water) flow-through model ecosystems were constructed to investigate the compartmentalization of different organic chemicals. Lindane, naphthalene, and mirex were pumped into the systems and resultant compartmental chemical concentrations determined. Steady state concentrations were compared to those predicted by two environmental fate models - EXAMS (Exposure Analysis Modeling System) and SLSA (Simplified Lake and Stream Analysis) which were developed by EPA-Athens, Georgia and HydroQual, Inc., respectively.
Date: December 1983
Creator: Staples, Charles A. (Charles Allen)
Partner: UNT Libraries

Biology and Production of Net-Spinning Caddisflies (Hydropsychidae And Philopotamidae) in a Regulated Portion Of The Brazos River, Texas

Description: Four species of net-spinning caddisflies, Hydropsyche simulans Ross, Cheumatopsyche lasia Ross, Cheumatopsyche campyla Ross and Chimarra obscura (Walker) are common in the regulated portions of the Brazos River. Hydropsyche simulans spun capture nets with the largest meshdimensions; the two Cheumatopsyche species' nets had the next largest meshes, and Chimarra obscura spun nets with the smallest dimensions. Cheumatopsyche lasia and C. campyla constructed nets with similar sized meshes. The number of individuals m~2 and standing crop biomass were not significantly different among low, medium, and high velocities. Early hydropsychid instars fed on detritus while later instar H. simulans and C. campyla had larger proportions of animal material. Guts of later instar C. lasia individuals had a greater percentage of algae and diatoms.
Date: May 1984
Creator: Malas, Diane M. (Diane Mary)
Partner: UNT Libraries