UNT Libraries - 622 Matching Results

Search Results

prev Results: 481 - 504 next
open access

Nymphs of the Stonefly (Plecoptera) Genus Taeniopteryx of North America

Description: Nymphs of the 9 Nearctic Taeniopteryx species were reared and studied, 1976-78. Two morphologically allied groupings, the Taeniopteryx burksi-maura, and T. litalonicera- starki complexes corresponded with adult complexes. A key separating 7 species, based primarily upon pigment patterns and abdominal setal arrangements, was constructed. Taeniopteryx lita and T. starki were indistinguishable; T. burksi was separated from T. maurawhen no developing femoral spur was present. This study was based u… more
Date: May 1978
Creator: Fullington, Kate Matthews
Item Type: Refine your search to only Thesis or Dissertation
open access

The Effect of Intermediate Filament Inhibitors on Steroidogenesis and Cytoskeleton in Y-1 Mouse Adrenal Tumor Cells

Description: When Y-1 mouse adrenal tumor cells were treated with sodium orthovanadate, an intermediate filament (IF) inhibitor in BHK21-F cells, there was no change in the amount of 20α-dihydroprogesterone produced. A neurofilament inhibitor, β, β'-iminodipropionitrile (IDPN), enhanced the ability of Y-1 cells to produce steroid in response to ACTH by acting on the plasma membrane. Electron microscopy of Y-1 cells extracted with Triton X-100 revealed that both vanadate and IDPN caused the aggregation of cy… more
Date: August 1982
Creator: Lee, Hyun Sook
Item Type: Refine your search to only Thesis or Dissertation
open access

The Evolutionary Genetics of Campostoma anomalum and Campostoma oligolepis

Description: Electrophoretic variation in 12 proteins encoded by 16 loci was analyzed to compare the genetic relationships of 18 natural populations representing two species of stoneroller minnows, Campostoma anomalum and C. oligolepis. Ten of the loci were monomorphic and fixed for the same allele in all populations of both species. One locus, Mdh-2, was found to separate both species. Mean heterozygosity for both species was 0.072. Estimates of levels of inbreeding indicated this phenomenon is operating i… more
Date: December 1978
Creator: Merritt, Ronald L.
Item Type: Refine your search to only Thesis or Dissertation
open access

Drumming Behavior of Selected North American Stoneflies (Plecoptera)

Description: Drumming is first described for five North American stonefly species, Acroneuria evoluta, Doroneuria baumanni, Isoperla namata, Chernokrilus misnomus, and Pictetiella expansa. Signals of Acroneuria lycorias, Phasganophora capitata and Isoperla signata are further described. Drumming was not recorded from Amhinemura delosa. Signals of A. evoluta are the most complex yet recorded in Plecoptera. Doroneuria baumanni, P. expanse, C. misnomus and P. capitata have 2-way exchanges. Male D. baumanni pro… more
Date: December 1983
Creator: Maketon, Monchan
Item Type: Refine your search to only Thesis or Dissertation
open access

Effects of N⁶,O²'-Dibutyryl Cyclic Adenosine 3' ,5' Monophosphate on Transformation of Rat Kidney Cells and Chick Embryo Fibroblasts by Wild-Type and Temperature-Sensitive Rous Sarcoma Virus

Description: N^6,O^2' -Dibutyryl cyclic adenosine 3',5'-monophosphate (Bt_2cAMP) was investigated for its effects on various tissue culture cells infected with temperature-sensitive (ts) mutant, LA31 and Bratislava 77 (B77), a wild-type Rous sarcoma virus. Specifically, known parameters of transformation were investigated and a possible site of action has been tenably proposed. The drug Bt_2cAMP was found to have little effect on the transformation related properties of primary chick embryo fibroblasts (CEF… more
Date: December 1983
Creator: Marshall, David A. (David Allen)
Item Type: Refine your search to only Thesis or Dissertation
open access

Comparative Toxicity of Refuse-Derived Fuel Fly Ash on Two Species of Earthworms, Lumbricus terrestris and E. foetida, Using an Artificial Soil Exposure Protocol

Description: Research estimated toxicity of refuse-derived fuel fly ash (RDF-FA) on two earthworms species, Lumbricus terrestris and Eisenia foetida. Specific objectives were to: (1) Compare their 14-day LC50s under light and dark conditions; (2) separate toxicity due to osmotic, pH and physical factors from that of heavy metal contaminants; (3) compare relative differences of artificial soil and commercial soil as exposure media for evaluating toxicity to earthworms. The 14-d LC50s for L. terrestris in dar… more
Date: May 1991
Creator: Jahani, Aghamolla
Item Type: Refine your search to only Thesis or Dissertation
open access

Effects of Exogenous Steroids on the Adrenal Plasma Membrane Alteration of Steroidogenesis and Cell Morphology

Description: Using cultured Y-1 mouse adrenal tumor cells which produce the steroid 20(-hydroxypregn-4-en-3-one (20-DHP), it was found that 10-5 M corticosterone and deoxycorticosterone increased basal and inhibited ACTH-induced 20-DHP production. The steroid effects were concentration-dependent, reversible, and specific since six other steroids did not stimulate steroidogenesis and varied in their ability to inhibit ACTH-induced steroidogenesis. Cytochalasin D inhibited steroid-stimulated 20-DHP production… more
Date: August 1982
Creator: Mattson, Mark Paul
Item Type: Refine your search to only Thesis or Dissertation
open access

Physiological Studies of the Bdellovibrio-Host Interaction

Description: The purpose of this study was to focus attention on the physiology of the bdellovibrio-host interaction and to determine the metabolic requirements for this reaction. Since bdellovibrio is an aerobic organism, direct measurements of respiration, turbidity, and viable cell counts are reliable indications of the metabolic activity of the cells. It was determined that the metabolic requirements for the parasitic interaction are constituents from either metabolically active host cells or cells whi… more
Date: December 1976
Creator: Dunton, Philip J.
Item Type: Refine your search to only Thesis or Dissertation
open access

Rapid Isolation and Purification of Plasmid DNA Using High Performance Liquid Chromatography

Description: High Performance Liquid Chromatography (HPLC) has been employed as an analytical tool for the purification and separation of nucleic acids. A Nucleogen DEAE 4000-10 weak anion exchange column, prepacked with modified silica gels, was used to purify and separate a number of Escherichia coli plasmids. Plasmid DNAs were extracted by the alkaline lysis method. The cleared lysate was injected directly onto the Nucleogen column, and the peaks were collected, desalted and analysed by gel electrophores… more
Date: May 1987
Creator: Nam, Kiebang
Item Type: Refine your search to only Thesis or Dissertation
open access

Distribution, Abundance, and Food Habits of Larval Fish in a Cooling Reservoir

Description: Analysis of larval fish collected at four stations in a 330-ha cooling reservoir indicated Dorosoma spp. were most numerous at all stations, followed by Lepomis spp. and Percina Macrolepida. Largest numbers and greatest diversity of larval fish were found at the station least affected by thermal effluent; the mid-lake station provided the smallest numbers and least diversity. The two warmwater stations were intermediate, with similar numbers and diversity. Diversity and abundance of zooplankton… more
Date: December 1978
Creator: Mitterer, Lana Gayle
Item Type: Refine your search to only Thesis or Dissertation
open access

The Effect of Human Alpha Interferon on Rat Kidney Cell Infected with Temperature-Sensitive Mutant of Rous Sarcoma Virus

Description: LA31-NRK and B77-NRK are established cell lines that were normal rat kidney cells transformed with temperature-sensitive mutant (LA31) and wild-type Bratislava 77 (B77) of Rous sarcoma virus. It is recognized that many transformation-induced changes differentiate between normal and transformed cells. Morphology and four parameters of transformed cells such as saturation density, anchorage independence, plasminogen activator, and colony stimulating factor were used as indicators to observe the e… more
Date: May 1983
Creator: Chang, Shiuan
Item Type: Refine your search to only Thesis or Dissertation
open access

Isolation and Partial Characterization of Pigment Mutants of Corynebacterium poinsettie ATCC 9682

Description: Carotenoid pigments were extracted from Corynebacteriuma poinsettiae (wild type) ATCC 9682, and from 108 mutants obtained by exposure of a streptomycin resistant strain of C. poinsettiae to ultra-violet light irradiation and N-methyl- N'-nitro-N-nitrosoguanidine. The pigments were characterized by their absorption maxima, Rf-values, and partition ratios in petroleum ether and methanol. Thin layer chromatography was used to compare pigments of the wild type with those of the mutants. Possible bi… more
Date: August 1980
Creator: Wariso, Benjamin A.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effect of Colchicine on Neuronal Excitabilty

Description: The abundance of microtubules in receptive dendrites suggests they may function in sensory transduction. Responses of frog muscle spindle receptors and joint receptors is inhibited within 25 minutes by 50 mM colchicine, a microtubuledisrupting agent. The inhibition is reversible upon removal of colchicine, and the time course of recovery is comparable to that of inhibition. Frog olfactory responses are briefly inhibited by washing the olfactory mucosa with perfusion fluid. Colchicine accentuate… more
Date: August 1978
Creator: Okafo, Ngozi
Item Type: Refine your search to only Thesis or Dissertation
open access

Genic Differentiation Between Two Chromosomal Races of Pocket Gophers, Geomys bursarius

Description: Genic data from two chromosomal races of Geomys bursarius from a contact zone in central Texas indicated that the two races possessed distinct gene pools which would define them as separate species. Data from proteins encoded from 21 loci in this study substantiated this hypothesis. A pattern of alternately fixed alleles at the ADH-l, MDH-2, LDH-l, and IDH-1 loci with no apparent gene flow in zones of contact strongly suggested that these two races should be designated as separate species. Leve… more
Date: May 1980
Creator: Bohlin, Raymond G.
Item Type: Refine your search to only Thesis or Dissertation
open access

An Assay Method for Determining Extra-Cellular Lipases from Pseudomonas aeruginosa

Description: The applicability of an isotopically labelled assay system to determine the lipase production in Pseudomonas aeruginosa was evaluated. Supernatant from cultures of Pseudomonas aeruginosa grown in a medium containing olive oil was incubated with a substrate containing labelled trioleate. Fatty acids were isolated by means of a liquid-liquid partition system. Enzyme activity was determined by measuring the amounts of free fatty acid by liquid scintillation counting. Findings indicate that the iso… more
Date: May 1978
Creator: Christensen, John N.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effects of Ribavirin on Normal Rat Kidney Cells and Chicken Embryo Fibroblasts Infected with Rous Sarcoma Virus

Description: Ribavirin, a synthetic nucleoside, was found to inhibit the replication of Rous sarcoma viruses (RSV) and subsequent cell transformation in chick embryo fibroblasts (CEF). It also blocked the transformation of normal rat kidney (NRK) cells infected with temperature-sensitive mutants of RSV. The action of Ribavirin was found to be reversible as removal of the drug from the NRK cells reversed the effects on cell transformation. Ribavirin appears to have a static effect on cell growth of both NRK … more
Date: April 1979
Creator: Jenkins, Frank J.
Item Type: Refine your search to only Thesis or Dissertation
open access

Thermal Selection at an Enzyme Locus in Populations of the Red Shiner, Notropis lutrensis, Receiving Hypolimnion Effluents from a Reservoir

Description: Genetic variation was examined at 19 loci encoding enzymatic and general proteins Notropis lutrensis from the Brazos River in Texas. The thermal regime of the Brazos River below Possum Kingdom Reservoir is altered due to the release of water from the hypolimnion. Summer water temperatures fluctuate as much as 7^oC. Levels of heterozygosity at the malate dehydrogenase-2 locus were correlated with the degree of water temperature fluctuation at each locality. The isozymes from three homozygous pat… more
Date: May 1978
Creator: Richmond, M. Carol
Item Type: Refine your search to only Thesis or Dissertation
open access

Permeability of the Kidney Capillaries to Narrow-Range Macromolecular Dextran Fractions

Description: Recent investigations into the permeability of the kidney capillaries have produced conflicting reports. This study was an attempt to better describe the permeability of the kidney capillaries by using narrow-range macromolecular dextran fractions in four molecular sizes: MW 61,400, MW 77,000, MW 118,000, and MW 147,000. Permeability was measured by dextran concentration differences in plasma and kidney lymph. Permeability decreased as the dextran molecular weight increased. Molecular weights 6… more
Date: August 1979
Creator: Wooldridge, Clayton Bradley
Item Type: Refine your search to only Thesis or Dissertation
open access

Immunocompetence in the AKR Mouse

Description: A model for the study of the relationship of immunity to cancer is found in AKR mice which harbor Gross virus. This genetically transmitted virus is present in a latent form for months before it spontaneously induces leukemia. Many investigators have demonstrated near normal humoral responses, but abnormal cellular immunity in the preleukemic animal. With increasing age, pathology of the disease is expressed, reflecting diminished immunity. In this study, the ontogeny of humoral antibodies of A… more
Date: August 1976
Creator: Dunton, Helen
Item Type: Refine your search to only Thesis or Dissertation
open access

The Effects of 3-Deazaguanine on Chick Embryo Fibroblasts and Rat Kidney Cells Infected with Temperature-Sensitive Mutant and Wild-Type Rous Sarcoma Viruses

Description: Chick embryo fibroblasts and rat kidney cells infected in vitro with Rous Sarcoma viruses were treated with 3-deazaguanine (3-DG). The findings revealed that 3-DG inhibited virus-induced cellular transformation. Degree of inhibition is dependent on concentration and frequency of media change. 3-DG at the concentrations tested will not reverse transformed cells to the untransformed state and does not have marked effect on replication of viruses. Upon removal of 3-DG, its effect was shown to be r… more
Date: December 1979
Creator: Fadare, Samuel O.
Item Type: Refine your search to only Thesis or Dissertation
open access

The Effect of Light on Carotenoid Synthesis in Corynebacterium 7E1C

Description: The effects of light, light "mimicking" chemicals, and protein synthesis inhibitors on the photo-induced carotenogenesis of Corynebacterium 7EIC were studied. Changes in the dosage of fluorescent light applied to dark grown cells showed a dose related carotenogenic response. Maintaining the same dosage but varying the wavelength of monochromatic light revealed that light with a wavelength of 280 to 450nm was responsible for photo-induction. It further showed a peak of photo-induction between th… more
Date: May 1977
Creator: Endicott, George R.
Item Type: Refine your search to only Thesis or Dissertation
open access

Failure of Azotobacter Vinelandii to Fix Nitrogen in Soil

Description: It was found that Azotobacter vinelandii grown in a dialyzed soil medium did not fix nitrogen and had a much lower rate of respiration than when grown in Burk's nitrogen-free medium. When para-hydroxybenzoic acid served as the added oxidizable organic carbon source in dialyzed soil medium, the azotobacter grown in it were found to be unable to fix nitrogen. On the other hand, A. vinelandii fixed nitrogen when grown in soil supplemented with glucose. It was concluded that natural conditions in t… more
Date: August 1983
Creator: Taeed-Kashani, Taraneh
Item Type: Refine your search to only Thesis or Dissertation
open access

Effect of Amino Acids on Growth and Cartenogenesis in Corynebacterium Species Strain 7E1C

Description: Studies were evaluated on the effects of known growth factors on the growth and carotenogenesis of Corynebacterium species strain 7ElC. The complex medium, Tryptic Soy Broth,was found to stimulate growth and production of more pigment in the light and in the dark than did a mineral salts-glucose medium. A complete amino acid mixture added to LSG enhanced carotenogenesis in the dark in Corynebacterium 7ElC, while B-vitamins retarded carotenogenesis. No absolute requirement for one or more amino … more
Date: May 1977
Creator: Coughran, Carolyn S.
Item Type: Refine your search to only Thesis or Dissertation
open access

Seasonal and Spatial Variability of the Microcrustacean Community in Lake Texoma, Texas and Oklahoma

Description: Twenty-eight species of zooplankton were identified from Lake Texoma. Seasonal density of the overall microcrustacean community and seasonal cycles of individual species were compared with northern populations and any available literature from the Southwest. Cycles of occurrence and abundance were similar to those observed in northern populations but tended to occur earlier in the year due to higher temperatures. Spatial distributions within the reservoir were heavily influenced by nutrient and… more
Date: August 1980
Creator: Crist, Lawrence W.
Item Type: Refine your search to only Thesis or Dissertation
Back to Top of Screen