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Effects of Turbidity on Gilling Rates and Oxygen Consumption on Green Sunfish, Lepomis cyanellus

Description: Laboratory studies conducted at 5, 15, 25, and 35 C measured changes in gilling rates and oxygen consumption of green sunfish in response to exposure to bentonite clay suspensions. The tests indicate that gilling rates are not affected by bentonite clay suspensions below 2125 FTU at 5 C, 1012 FTU at 15 C, and 898 FTU at 25 C. At turbidity levels exceeding 1012 FTU at 15 C and 898 at 25 C, gilling rates increased 50-70%. Tests were inconclusive at 35 C. Oxygen consumption rates were found to be unaffected by turbid suspensions below 3500 FTU at all four temperatures. Evidence suggests that increased gilling rates under highly turbid conditions are a means of compensating for reduced respiratory efficiency and a strategy for maintaining a constant oxygen uptake. Evidence indicates that the cost of increased gilling rates is probably met by a reduction in activity.
Date: May 1974
Creator: Horkel, John Duane

Biochemical Genetics of Certain Species of the Blackbird Family Icteridae

Description: Starch gel electrophoresis was used to compare 14 proteins encoded by 15 loci for seven species of the family Icteridae. A close genetic relationship among these species was classified into three groups. The Agelaiine group contained Agelaius phoeniceus, Sturnella magna, and S. neglecta. The Quiscaline group contained Euphagus cyanocephalus, Cassidix mexicanus, and Quiscalus quiscula. Molothrus ater, the most divergent, was placed in a separate group. Divergence times for the seven species were compared to the literature. Heterozygosity of the seven populations of the two species of Sturnella were compared to determine factors influencing their divergence. Two factors proposed were heterosis in S. neglecta and possible hybridization between S. neglect and S. magna.
Date: December 1974
Creator: Smith, Jackson Kelly

The Stoneflies (Plecoptera) of Texas

Description: An illustrated key to the adults and known nymphs of Texas Plecoptera is provided. Species accounts, including geographic distribution within Texas, and biological notes are given. Of the twenty-seven species of Plecoptera known from Texas, six are new state records. TWo species new to science, Isoperla jewetti and Isoperla coushatta are described. Taeniopteryx starki Stewart and Szczytko, Zealeuctra arnoldi Ricker and Ross, and Zealeuctra hitei Ricker and Ross are endemic to the Edwards Plateau area of Texas. Two species, Mesocapnia frisoni (Baumam and Gaufin) and Isoperla jewetti New Species are western in origin. The remaining nineteen species (excluding Anacroneuria) are typically eastern species.
Date: May 1975
Creator: Szczytko, Stanley W.

Evolutionary Genetics of Three Semispecies of Wood Rats--Neotoma Albigula, Neotoma Micropus, and Neotoma Floridana

Description: Electrophoretic variation in 18 proteins encoded by 20 autosomal loci was used to compare the genetic relationships of 19 natural populations representing three species of the subgenus Neotoma. Of the 20 loci examined nine were monomorphic and fixed for the same allele in all populations. No more than seven loci were polymorphic within a single population. Genetic variability was expressed as the proportion of loci heterozygous in the average individual of a population. Heterozygosity in the three species of Neotoma studied averaged 0.078, a value within the range reported for other rodents. Although the levels of heterozygosity seen in Neotoma could not readily be explained, the variation may be attributed to ecological factors. The three species of Neotoma were compared on the basis of genetic similarity and found to form a close taxonomic unit, probably semispecies. Divergence times were obtained for the three species and found to compare well with divergence times obtained from fossil data. In general, the three species have diverged within the last 112,000 years during the Wisconsin glacial period.
Date: December 1975
Creator: Nejtek, Michael E.

Genic Differentiation and Evolution in the Ground Squirrel Subgenus Ictidomys (Spermophilus)

Description: The genetic structure of 26 natural populations of three species (S. tridecemlineatus, S. mexicanus, and S. spilosoma) of the Ictidomys subgenus of ground squirrels was analyzed using chromosomal and electrophoretic techniques. Chromosomal variation was not observed in S. mexicanus, and only slight karyotypic variation was found in the other two species. Chromosomal evidence indicated hybridization between S. tridecemlineatus and S. mexicanus, placing these species within the classical definition of semispecies. Analysis of electrophoretic variation at 29 genetic loci indicated close genetic relationships between these species. Evolution in Ictidomys appears to be linked with Pleistocene events, and speciation appears to have occurred within the last 155,000 years.
Date: December 1975
Creator: Cothran, E. Gus, 1951-

Hematological Parameters of the Bluegill, Lepomis machrochirus (Rafinesque), Including Effects of Turbidity, Chloramines, and Flexibacter columnaris

Description: Normal ranges of values for hematological parameters of bluegill gathered seasonally from three lakes were determined. Sexual, seasonal, and inter-lake variations were found. Effects of 2-wk exposure to turbidity on blood parameters included an increase in rbc size and a decrease in small lymphocytes. Effects of 3-hr exposure were increases in rbc count, hemoglobin, and pH and decreases in PG2 and large lymphocytes. The effects of 0.44 and 0.88 ppm chloramines were an increase in blood pH, a decrease in MEV, and severe spastic reactions resulting in loss of equilibrium or death in 90% of the fish. Effects of Flexibacter columnaris included an increase in transformed lymphocytes and a decrease in small lymphocytes.
Date: May 1976
Creator: Jones, Betty Juanelle

Drumming Behavior of Selected Nearctic Stoneflies (Plecoptera)

Description: Drumming was recorded for 11 of 13 Nearctic stonefly species, representing 4 families. Both male and female signals were obtained from 5 species, and were either 2-way or 3-way communications. Signals were species-specific; those of males and females varied from 3-39 and 1-14 beats/ signal, respectively. Duration of male signals varied from 105-8,016 ms; those of females, except Perlinella drymo (1 beat), varied from 402-1318 ms. Signals among related taxa showed greatest similarities. Duration of male signals of Perlinella drymo became progressively shorter at each of 4 temperatures from 7-29 0C. Females of Perlinella drymo would only repeatedly answer male signals recorded at near their own temperature, and would not repeatedly answer recorded male signals of 8 other species.
Date: August 1976
Creator: Zeigler, David D.

The Effect of Ethanol on Cardiac Activity and Brain Respiration in Chick Embryos

Description: This study concerned the effect of ethanol on cardiac activity and brain respiration in chick embryos. Ethanol dosages tested ranged from 1.0 mg to 4.0 mg/g weight. Each experiment lasted at least 150 minutes. Cardiac activity in terms of total waveform energies was integrated and printed out for plotting and analysis. The embryonic heart rates were simultaneously determined from physical graph tracings. The embryonic brain respiration was measured using a differential microrespirometer. The effect of ethanol on cardiac activity was one of slight (10 to 13), but statistically significant (p<.05) rate depression. The brain slices exhibited a marked, immediate, and irreversible decrease (39 to 89%) in oxygen consumption at both ethanol dosages. The data indicated that chick embryonic brain tissues were more susceptible to alcohol effects than cardiac tissue. Therefore, the mental abnormalities seen in the offspring of alcoholic mothers may be more cerebral in nature than cardiovascular.
Date: August 1976
Creator: Newman, James J.

Food Habits of Stoneflies (Plecoptera) in the Gunnison and Dolores Rivers, Colorado

Description: Gut contents of 2,500 stonefly nymphs, comprising 10 species, from the Gunnison and Dolores Rivers, Colorado were examined from Dec., 1974-Oct., 1975. Perlidae species were carnivorous feeding primarily on chironomids, mayflies and caddisflies. Seasonal patterns of ingestion and preference varied among species and predator sizes and between rivers. Early instar polyphagous species utilized detritus in the fall, eventually shifting to carnivorous habits as they grew through winter-spring. Pteronarcids fed predominantly on detritus. Dietary overlap of predators was greatest in the Gunnison River, with subtle mechanisms such as prey species and size selectivity, temporal succession and seasonal shifts to detritus-plant material in some, providing reduction of competition. A more complete partitioning of prey resources was evident in the Dolores River.
Date: August 1976
Creator: Fuller, Randall L.

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 AKR/J and SWR/J mice was assayed by microagglutination techniques in response to thymus-independent, thymus-dependent, and solubilized antigens. Simultaneous injections of thymusdependent and -independent antigens provided data suggesting an impaired humoral response in the AKR mouse.
Date: August 1976
Creator: Dunton, Helen

Comparative Chemistry of Thermally Stressed North Lake and Its Water Source, Elm Fork Trinity River

Description: To better understand abiotic dynamics in Southern reservoirs receiving heated effluents, water was analyzed before and after impoundment in 330 ha North Lake. Macronutrients, metals, and chlorinated hydrocarbons were measured. Concentrations of nutrients and metals in sediments were quantified in this 2 yr study. River water prior to impoundment contained 16 times more total phosphorus, and supported 23 times more Selenastrum capricornutum cells in an algal assay than reservoir water. The reservoir has essentially no drainage and since evaporation is high, the concentrations of many dissolved solids have increased since the reservoir was filled in 1958. North Lake is now phosphorus limited. Apparently altered chemical equilibria have caused precipitation or adsorption of phosphorus with calcium and iron.
Date: December 1976
Creator: Sams, Barry L.

DNA-DNA Hybridization of Methane Oxidizing Bacteria

Description: Bacteria classified in the family Methylomonadaceae must derive their carbon from one-carbon compounds. They are characterized by the possession of internal membranes of two types. Type I membranes are layered and fill the middle of the cells while type II membranes form concentric layers around the periphery of the cells. Also, there are two metabolic pathways by which the methylobacteria assimilate one-carbon compounds. Further evidence of this dichotomy was sought by DNA-DNA saturation hybridization of DNAs from both types of methylobacteria. Very low DNA-DNA homology was seen between types I and II or within the types. It was not possible, therefore, to correlate the degree of genetic relatedness with either the nature of the internal membranes or the pathway of carbon assimilation.
Date: December 1976
Creator: Ackerson, Jill W.

Serological Relationships of Azotobacter Species

Description: In order to clarify the taxonomic problems which exist among the group azotobacter by serological method, 24 cultures of Azotobacter including 9 species were tested as antigens in Ouchterlony plates against 3 different antisera obtained from rabbits immunized with A. chroococcum ACl6, A. macrocytogenes St.M. and A. vinelandii 12837, respectively. The results showed more cross reactivity in intraspecies reactions than in interspecies ones and indicated the presence of a common immunogenic determinant. This work presents the results which suggest the effecient classification of Azotobacter by Ouchterlony comparisons of corresponding antigens in different species.
Date: December 1976
Creator: Chang, Chyan-chuu

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 acids was found,indicating a multiple amino acid requirement. The fewest amino acids found to stimulate carotenogenesis in the dark were a combination of those in the Serine and Histidine families which include serine, glycine, cysteine, and histidine.
Date: May 1977
Creator: Coughran, Carolyn S.

A Study of the Water-Soluble Antigens from Virulent and Attenuated Biotypes of Brucella abortus

Description: Through chemical analysis and ion exchange chromatography of watersoluble antigens, this investigation supports the view that the majority of differences between the biotypes are quantitative. It was also found that strains demonstrate distinct, qualitative differences when compared to the attenuated strain 19 by immunodiffusion and thin-layer polyacrylamide gel, isoelectric focusing. These differences include the presence of antigens on virulent strains that are absent on strain 19. In addition, one antigen absent on strain 19, was found common to each virulent biotype. Finally, the results from immunodiffusion experiments, employing adsorbed and non-adsorbed immune globulins, indicate that at least some water-soluble antigens are exposed on the cell surface and that their distribution among the biotypes varies.
Date: May 1977
Creator: Brodeur, Richard D.

The Relation Between Carbon Assimilation and Biomass Dynamics in a Phytoplankton Community

Description: Production dynamics in the phytoplankton community of a mesotrophic Texas reservoir were measured weekly over a four month period using 14C incubation and ATP assay methodologies. Assimilation values of 14C ranged from 0.2 to 45 ug C 1 hr1 - . Significant positive and occasionally negative changes in biomass (i.e. viable organic carbon) were observed in short term (4 hr) in situ incubations juxtapo-sitioned with the 14C experiments; viable organic carbon production, estimated with the ATP assay, ranged from -25 to +50 ug C 1l1hr1. Carbon assimilation and biomass changes did not correlate in either short term (4-5 hr.) or over the study period (6 months). However, weekly biomass trends were predicted by relative positive or negative biomass changes in the short term incubations. Biomass measurements gave a more sensitive insight into production dynamics in the phytoplankton community than did carbon assimilation measurements.
Date: December 1977
Creator: Wilcox, Douglas P.

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 isotopicallylabelled, liquid-liquid partitioning assay is reliable, sensitive and adaptable to rapid assay conditions. It was also determined that different strains of Pseudomonas aeruginosa produce varying amounts of lipase. Partial purification of supernatant by gel filtration produced two protein peaks showing enzymatic activity.
Date: May 1978
Creator: Christensen, John N.

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 upon 839 nymphs. Mouthparts were not species-diagnostic. Detailed habitus illustrations were made for 6 species. Egg SEM study revealed that 3 species were 1.2-1.4 mm diameter, with a highly sculptured chorion, generally resembling a Maclura fruit; micropyle were scattered. Taeniopteryx lita, lonicera, starki and ugola nymphs were described for the first time.
Date: May 1978
Creator: Fullington, Kate Matthews

Production and Energy Metabolism in Three Benthic Insect Populations in a Small North Central Texas Pond

Description: Annual energy budgets of dominant benthic macro-invertebrates were examined during November 1973 to October 1974 from the benthos of a small pond ecosystem in north-central Texas. Estimates of annual secondary production (Hynes and Coleman 1968) were Procladius s. (Diptera, Chironimidae), 2.4 g m^-2 y^-1 (13 kcal m^-2 y^-1 ); Tendipes decorus (Diptera, Chironomidae), 6.0 g m^-2 y^-1 (40 kcal m^-2 y^-1 ); Brachycercus sp. (Ephemeroptera, Caenidae), 1.9 g m^-2 y^-1 (11 kcal m^-2 y^-1). Energy metabolism was measured in the laboratory at six seasonally encountered temperatures (5, 10, 15, 20, 25, and 30 C) on an acclimatization basis, and then extrapolated to the field. Estimates of annual energy metabolism are Procladius sp., 5.0 kcal m^-2 y^-1 ; Tendipes decorus, 17.2 kcal m^-2 y^-1 ; Brachycercus sp. 40.0 kcal m^-2 y^-1.
Date: May 1978
Creator: Benson, Daniel J.

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 patterns of supernatant malate dehydrogenase (Mdh-l, Mdh-2) exhibited different activities at different experimental temperatures.
Date: May 1978
Creator: Richmond, M. Carol

Trophic Structure and Energy Flow in a Texas Pond

Description: Annual energy flow and mean annual biocontent of eighteen compartments were determined for a 0.94 ha north central Texas pond ecosystem. Annual primary production was 7,780 kcal m^-2 yr^-2, and community production-to-respiration ratio was 1.49. One-third of annual primary production accumulated on the substrate as silt and sedimentation. Community production, production-respiration ratio, and biocontents of all compartments except aquatic insects were large in summer, small in winter. Biocontents of four trophic levels in the pond were all of the same order of magnitude, approximately 50 kcal m^-2. Suspended and benthic organic material forprimary consumers and terrestrial insects for tertiary consumers were substantial allochthanous energy imports into the pond system.
Date: August 1978
Creator: Childress, William M.

Use of ATP as a Planktonic Biomass Indicator in Reservoir Limnology

Description: A series of laboratory experiments and a field investigation were conducted to closely define the application of the ATP assay and ATP as a planktonic biomass estimator for routine use in reservoir limnology. The laboratory experiments verified the published range of C:ATP ratios (i.e. 250:1) as a conversion factor for ATP to biomass in cultured selected genera of freshwater algae, except for the species of blue-green algae examined. The field investigation conducted at Moss Reservoir included organic carbon measurements with ATP biomass in size classes on a depth basis. The ATP biomass varied seasonally and with depth; the best significant mtltiple correlation was between organic carbon and the smallest size class (.45 to 10 um) and total net plankton biomass (.45 to 165 um). Daily monitoring of biomass in size classes demonstrated the sensitivity of the technique.
Date: August 1978
Creator: Perry, William B.

Dielectric Properties of Azotobacter vinelandii in a Microwave Field

Description: A resonant frequency cavity was used to determine the dielectric properties of various preparations of Azotobacter vinelandii ATTC 12837. It was found that the bacteria investigated did interact with microwave radiation in the absence of free water. The data presented here indicate that bacteria demonstrate frequency specific dielectric properties. The techniques employed in these experiments may also be used to determine microwave spectra of other species of bacteria in different physiological stages.
Date: December 1978
Creator: Hargett, John M.

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 between stations were similar to those of fish. The most abundant zooplankter (Bosmina) was generally selected against by Dorosoma, Lepomis and Micropterus spp. larvae except when the larvae were quite small ((10mm). Cyclopoid copepods were most often selected by all larvae.
Date: December 1978
Creator: Mitterer, Lana Gayle