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Life Histories Behavior and Space Partitioning in Selected Species of Western North American Plecoptera (open access)

Life Histories Behavior and Space Partitioning in Selected Species of Western North American Plecoptera

Five species of stoneflies (Zapada haysi, Plumiperla diversa, Taenionema pacificum, Isoperla petersoni, Arcynopteryx compacta) from the North Slope and Interior of Alaska were examined for seasonal patterns of emergence of adults and growth of nymphs. Generally growth was retarded during the winter in this region, and all species except I. petersoni completed growth prior to January. The life cycles of six stonefly species (Prostoia besametsa, Triznaka signata, Sweltsa coloradensis. Isoperla fulva, Skwala parallela, Claassenia sabulosa) are described from northern New Mexico. In this region growth was generally less retarded during the winter than in Alaska; P. besametsa completed all nymphal growth during late fall and winter. Drumming behavior of a Colorado population of Pteronarcella badia was described using an evolutionary framework to explain the maintenance of signal variation in this species. Laboratory experiments were used to explore the effect of intraspecific and interspecific interactions on spatial partitioning in P. badia and Claassenia sabulosa. P. badia exhibited clumping and distributed itself as the surface area of substrate in low densities; however, in the presence of C. sabulosa its distribution was random and different from available surface area. A field study was used to examine spatial partitioning by three New Mexico stonefly …
Date: August 1988
Creator: Hassage, Rodney Lynn, 1947-
System: The UNT Digital Library
Multivariate Analyses of Amphibian and Reptilian Distribution in Texas (open access)

Multivariate Analyses of Amphibian and Reptilian Distribution in Texas

Presence-absence data for amphibians, chelonians, saurians, ophidians, and the terrestrial and aquatic ecological guilds of reptilians were analyzed using multivariate analyses. Geographically consistant distributional patterns were found for all faunal groupings. The correspondence between analyses of the different taxa and guilds was not perfect, but similarities were found. All analyses agreed on the presence of a distinctive region in east Texas. Most analyses also agreed on the presence of distinctive regions in south Texas, the Trans-Pecos, the Edwards Plateau, and north-west Texas. There is strong correspondence between interpretations of the analyses based on the amphibian, saurian, ophidian, and terrestrial reptilian distributions, and the biotic provinces produced by earlier, subjective analyses. The Edwards Plateau and a region on the western periphery of east Texas were found to be transitional between other, more faunally distinctive areas for most fauna! groups. Detailed examination of these regions suggested they are best described as clinal in nature. The environmental variables which were most effective in explaining patterns in the distribution of the various taxa and guilds were related to precipitation. However, variations in temperature and physiography were also important predictors of distribution for several of the groups. The distributions of soil and vegetation associations were …
Date: August 1988
Creator: Ward, Rocky
System: The UNT Digital Library
Physiological Responses of Myriophyllum spicatum to Time Varying Exposures of Diquat, 2,4-D and Copper (open access)

Physiological Responses of Myriophyllum spicatum to Time Varying Exposures of Diquat, 2,4-D and Copper

The physiological responses of Myriophyllum spicatum to 2,4-D, diquat and copper were quantified using a plant tissue viability assay, and daily measures of dissolved oxygen and pH. Correlations of herbicide tissue residues to physiological response measures were determined and the relationship was used to develop exposure-response models. Diquat and copper had a greater effect on plant tissue viability than was observed for 2,4-D. Diquat produced greater reductions in dissolved oxygen concentrations and pH values than 2,4-D or copper. Copper exposure had the least effect on these parameters. Exposure-response models developed for 2,4-D predicted effective control at plant tissue residues ranging from 4000 to 4700 mg/kg. Aqueous exposure concentrations necessary to produce effective control plant tissue residues ranged from 0.20 to 0.40 mg/L. Exposure-response models developed for diquat predicted effective control at plant tissue residues ranging from 225 to 280 mg/kg. Aqueous exposure concentrations necessary to produce effective control plant tissue residues ranged from 0.113 to 0.169 mg/L. Exposure-response models developed for copper predicted effective control at plant tissue residues ranging from 680 to 790 mg/kg. Aqueous exposure concentrations necessary to produce effective control plant tissue residues ranged from 0.32 to 0.64 mg/L. Model predictions for 2,4-D, diquat and copper were …
Date: May 1988
Creator: Rocchio, Patricia Mary
System: The UNT Digital Library
Genetic Differentiation of the Geomys Pocket Gopher Complex of Texas (open access)

Genetic Differentiation of the Geomys Pocket Gopher Complex of Texas

Genetic variation was analyzed for populations of seven taxa comprising four cytotypes of the Geomys bursarius chromosome complex, including G. b. major, G. b. knoxjonesi, and the Edwards Plateau taxa, G. b. llanensis and G. b. texensis. Genetic relationships of the Edwards Plateau gophers with other taxa and between themselves were examined. Genetic similarity, number of fixed allelic differences, and ectoparasite distribution indicate the Edwards Plateau gophers are a distinct gene pool. Isolation of the Edwards Plateau taxa precludes contact zone analysis. However, genetic differentiation is typical of that between other species of Geomys, and the Edwards Plateau taxa should be recognized as G. texensis. Distributions of allelic frequencies indicate little justification in retaining the subspecific status of the Edwards Plateau forms.
Date: August 1988
Creator: Block, Scott B. (Scott Bishop)
System: The UNT Digital Library
The Effect of N, N Bis (ethylene)-P (1-adamantyl) Phosphonic Diamide on Rous Sarcoma Virus (open access)

The Effect of N, N Bis (ethylene)-P (1-adamantyl) Phosphonic Diamide on Rous Sarcoma Virus

The drug, N,N bis (ethylene)-P (1-adamantyl) phosphonic diamide inhibits focus formation of Rous Sarcoma Virus in tissue culture. Transformation of chick cells was inhibited when the drug was added to chick cells prior to infection. The drug did not inhibit the transformation of Normal Rat Kidney Cells infected with RSV, when the cells were grown at non-permissive temperatures and shifted to permissive temperatures upon addition of the drug. Nor did the drug revert cells transformed at permissive temperatures. These studies indicated that the inhibition of RSV is in the early stage of viral growth, possible penetration or uncoating.
Date: March 1988
Creator: McGraw, Thomas L. (Thomas Lee)
System: The UNT Digital Library
Genetic Variation in a Population of the Plains Woodrat Neotoma micropus (open access)

Genetic Variation in a Population of the Plains Woodrat Neotoma micropus

Neotoma micropus from Jack County, Texas, were studied over a 9-month period. Loci from blood and saliva were used to determine genetic variation within the population. Deviations from Hardy-Weinberg equilibrium were found at one locus. The average temporal F over all seven loci was 0.040. Genetic structuring was subtle, fluctuated on a seasonal basis, and was due to differential migration or predation on genotypes. Heterozygotes tended to move more than homozygotes, and a greater proportion of heterozygotes were lost from the population during each season. Genetic variation was maintained in the population by immigrant individuals. This differential in dispersal of genotypes fits current models of reorganization within the genome of populations.
Date: August 1988
Creator: Stewart, John E. B. (John Edward Bakos)
System: The UNT Digital Library
Adenylate Energy Charge Determinations of Soil Bacteria Grown in Soil Extract Medium (open access)

Adenylate Energy Charge Determinations of Soil Bacteria Grown in Soil Extract Medium

The adenylate energy charge values of twenty bacteria isolated from soil and cultured in a medium consisting of soil and distilled water were determined by the luciferin-luciferase bioluminescense method. The purpose of this study was to examine the growth and energy charge values of these organisms in soil extract medium, and to determine what effect the addition of glucose has on their energy charge values. Three of the organisms employed in this study showed energy charge values similar to those reported for bacteria grown in enriched media. The remainder of the isolates demonstrated low energy charge values, and scant growth in the soil medium.
Date: August 1988
Creator: Rodriguez, Luis A. (Luis Antonio)
System: The UNT Digital Library
Neuronal Survival After Dendrite Amputation: Investigation of Injury Current Blockage (open access)

Neuronal Survival After Dendrite Amputation: Investigation of Injury Current Blockage

After dendrite transection, two primary injury current pathways may acount for cell death: (1) the lesion current at the site of injury and (2) the voltage sensitive calcium channels along the dendrite. Lesions were made with a laser microbeam in mouse spinal monolayer cell cultures. Polylysine was tried as a positively charged "molecular bandage" to block the lesion current. The calcium channel blockers, verapamil and nifedipine, were used to reduce the calcium channel current. Control toxicity curves were obtained for all three compounds. The results show that neither verapamil, nifedipine, nor polylysine (MW: 3,300) protect nerve cells after dendrite amputation 100 ptm from the soma. The data also indicate that these compounds do not slow the process of cell death after such physical trauma.
Date: December 1988
Creator: Shi, Ri Yi
System: The UNT Digital Library
Production, Location, and Binding of Violacein in Janthinobacterium (open access)

Production, Location, and Binding of Violacein in Janthinobacterium

Violacein is a purple pigment typically produced by species of Chromobacterium and Janthinobacterium. A soil isolate, identified as Janthinobacterium, was studied. Maximal pigmentation occurred at 250C under aerobic conditions in the Keeble and Cross medium. Intracellular pigment was shown to be located in the cell membrane. Comparision of pigment production and growth curves indicated that violacein is synthesized in the cell and released into the environment possibly as a result of cell lysis. Extracellular pigment is water soluble, makes up 60% of the total pigment and shows a blue shift when compared to solvent extracted pigment. Results from purification indicated that the pigment is non-covalently bound to a small protein and aggregated into a larger molecule.
Date: May 1988
Creator: Lin, Ying-Chuan
System: The UNT Digital Library
Niche Structure of an Anole Community in a Tropical Rain Forest within the Choco Region of Colombia (open access)

Niche Structure of an Anole Community in a Tropical Rain Forest within the Choco Region of Colombia

Ten species of anoles at Bajo Calima within the Choco of Western Colombia separate into two principal microhabitat groups: forest species, and those inhabiting openings and edges. The ten anoles further separate according to ground and vegetation dwellers. There is a relation at Bajo Calima between the number of anole species and vegetational structural diversity. Anole diversity within a given macrohabitat is by perch microsite/microclimate heterogeneity. These are the two major ecological dimensions along which similarity is limited or resources are partitioned.
Date: May 1988
Creator: Castro-Herrera, Fernando
System: The UNT Digital Library
Effects of Lysolecithin on Macrophages (open access)

Effects of Lysolecithin on Macrophages

The effect of lysolecithin on the macrophage was studied using five macrophage function assays. The results of indicate that lyso lecithin is a macrophage activating agent which causes enhanced cell spreading, increased phagocytosis of sheep erythrocytes, heightened membrane activity in the presence of damaged autologous red blood cells, chemotaxis, and vigorous phagocytosis and intracellular killing of Staphylococcus albus.
Date: May 1988
Creator: Swee, Mei Hua
System: The UNT Digital Library