UNT Libraries - 148 Matching Results

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open access

Identification of Glycine as the Factor in Peptone Which Induces Pleomorphism in Azotobacter Vinelandii

Description: The rigid peptidoglycan layer of the cell wall is responsible for maintaining the structural integrity of bacteria. Antibiotics such as penicillin exert their anti-bacterial effect by inhibiting synthesis of peptodoglycan, and enzymes such as lysozyme destroy cell integrity by hydrolyzing specific bonds in the interior of this macromolecule. Defective cells can no longer withstand the high turgor pressure within the cell because they are no longer protected by a rigid wall and tend to become fr… more
Date: December 1972
Creator: Rosenthal, Raoul Simon
Item Type: Refine your search to only Thesis or Dissertation
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Effects of Nutrient Media on Growth and Morphology of Azotobacter Vinelandii

Description: The work described in this thesis was undertaken to study the reasons why Azotobacter vinelandii ATCC 12837 after incubation in Burk's nitrogen-free liquid will not form as many colonies when plated on Difco Tryptic Soy Agar as when planted on Burk's nitrogen-free agar. The difference in growth of A. vinelandii on the two agars was established by performing viable cell-plate counts. The difference in growth was most apparent at 24-hours incubation of the Burk's liquid-media cultures. Phase cont… more
Date: August 1974
Creator: Butsch, Robert W.
Item Type: Refine your search to only Thesis or Dissertation
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A Comparison of Thermogenesis by Selected Substrates on Hypothermic Rat Liver

Description: The thermogenic effects in hypothermia of four substrates--alanine, glycine, ethano, and pyruvate - were studied in seventeen experiments. Albino rats were decapitated, and their livers were removed. The livers were homogenized with phosphate buffer at -5° C. After equilibration in a refrigerated Warburg apparatus at 20° C, the substrates were added and tissue respiration was recorded over three hours. Heat production was calculated from O2 uptake and CO2 production. Results showed that alanine… more
Date: August 1979
Creator: Long, James T.
Item Type: Refine your search to only Thesis or Dissertation
open access

Linkage Relationships of Greenbug Resistance in Barley, Hordeum Vulgare L.

Description: The linkage relationship and arm location of the gene for greenbug resistance in the variety Will was determined by using primary trisonomics and tertiary trisomic homozygous translocations. The gene for greenbug resistance was found to be on linkage group 1 by using primary trisonomics. The gene was located on the cetromere segment of the Tl-6a translocation by using a tertiary trismoic homozygous for greenbug resistance. The data further substantiates the feasibility of using trisomics in pla… more
Date: December 1972
Creator: Gardenhire, James H.
Item Type: Refine your search to only Thesis or Dissertation
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Fumarase From Ascaris Suum: Partial Purification and Characterization

Description: One molecular form of fumarase from Ascaris suum was demonstrated by cellulose acetate electroporesis and isoelectric focusing. The enzyme was partially purified by ammonium sulfate fractionation and ion-exchange chromatography to a specific activity of 49 units per mg protein. Enzymatic assay of the partially purified by ammonium sulfate fractionation amd ion-exchange chromatography to a specific activity of 49 units per mg protein. Enzymatic assay of the partially purified preparation showed… more
Date: May 1976
Creator: Powley, David G.
Item Type: Refine your search to only Thesis or Dissertation
open access

Protein Profiles of Azotobacter Vinelandii During the Encystment Process

Description: Azotobacter vinelandii 12837 was grown in Burk's glucose media and transferred onto Burk's n-butanol agar plates to allow for the formation of cysts. The patterns of the vegetative cell proteins were compared for each successive day of cyst formation, using the polyacrylamide gel isoelectric focusing technique. The findings revealed that, as the cysts developed to maturity, definite changes occurred in the protein constitution, indicative of the biochemical and physiological changes which cells… more
Date: August 1977
Creator: Butler, Mark A.
Item Type: Refine your search to only Thesis or Dissertation
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Relationship of Certain Fungi to Azotobacter in Nitrogen-Free Media

Description: Azotobacter and various fungi were grown together in nitrogen-free media. Maximal fungal growth in the medium used was possible only at the expense of Azotobacter cells and growth was always accompanied by acid production. When the medium reached a pH of 2, the bacterial cells were aggregated on fungal hyphae and the culture fluid appeared to be free of Azotobacter. Aspergillus niger grew well at the expense of viable bacteria and other fungi grew well on heat-killed cells of A. vinelandii. Mem… more
Date: August 1976
Creator: Ray, Manfred G.
Item Type: Refine your search to only Thesis or Dissertation
open access

Colchicine Reversibly Inhibits Electrical Activity in Arthropod Mechanoreceptors

Description: Dendrites of cockroach tibial spine mechanoreceptors contain hundreds of free microtubules, which may have some relation to the generation of electrical activity. Deflection of a spine produces a train of action potentials. Continuous perfusion over a period of 4 hours results in no response decrement. Perfusion with 10mM colchicine reversibly inhibits the response within 5-7 minutes. Irreversible inhibition is produced by perfusion with 1mM vinblastine sulfate in perfusion solution containing … more
Date: August 1977
Creator: Reagan, Paul D.
Item Type: Refine your search to only Thesis or Dissertation
open access

A Multiphasic Study of the Interaction Between the Branchiobdellid Cambarincola Vitrea and its Crayfish Host Procambarus Simulans

Description: The host-parasite interface between the branchiobdellid Cambarincola vitrea Ellis and its crayfish host is investigated along ecological, ultrastructural, serological, and endocrinological lines of evidence. Monthly analysis of a natural branchiobdellid from a vernal habitat demonstrates the annelid to be particularly sensitive to changes involving both the physical habitat as well as the host crayfish.
Date: August 1973
Creator: Koepp, Stephen John
Item Type: Refine your search to only Thesis or Dissertation
open access

Purification and Characterization of Aldolase From Ambystoma Tigrinum

Description: The muscle aldolase from Ambystoma tigrinum has been purified 73-fold to a final specific activity of 13.2 units per mg. The purified enzyme appeared to be homogenous by ultracentrifugation and electrophoretic criteria. A molecular weight of 159,000 + 1000 was determined by gel filtration on Sephadex G-200 and high speed sedimentation equilibrium ultracentrifugation. The enzyme migrated identically with rabbit muscle aldolase when subjected to sodium dodecyl sulfate polyacrylamide gel electroph… more
Date: December 1975
Creator: Woolever, Dorothy J.
Item Type: Refine your search to only Thesis or Dissertation
open access

The Life Cycle of Hydroperla Crosbyi (Needham and Claassen) (Plecoptera: Perlodidae)

Description: Data on the life cycle of Hydropezrla crosbvi were collected from January, 1974, to March, 1976, in Clear Creek, Denton County, Texas. Laboratory investigation helped in establishing instar number, egg incubation and description, and first instar descriptions. Adult Hydroperla crosbyi emerge in February - March when water temperature increases to a mean of 15 C. Eggs undergo a diapause, hatching when decreasing water temperature reaches 18 C in October - November. Maximum growth occurs when wat… more
Date: August 1976
Creator: Oberndorfer, Reed Y.
Item Type: Refine your search to only Thesis or Dissertation
open access

Chemical Composition of the Peptidoglycan of Vitreoscilla Stercoraria

Description: The peptidoglycan layer of Vitreoscilla stercoraria, ATCC 15218, was isolated from intact cells after treatment with sodium lauryl sulfate (SLS) and digestion with Pronase. Amino acid and amino sugar content was analyzed and 67% of the total present was made up of glutamic acid, alanine, diaminopimelic acid (DAP), and glucosamine in a molar ratio of 1:1.7:1:0.7. Electron microscopy of the final peptidoglycan product showed a thin, delicately folded sacculus which exhibited a morphology differen… more
Date: August 1976
Creator: Levit, Gary
Item Type: Refine your search to only Thesis or Dissertation
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Purification and Characterization of Ascaris Suum Hexokinase

Description: Hexokinase has been found in a soluble and a bound form in homogenates of Ascaris suum muscle. Cellulose acetate electrophoresis, isoelectric focusing, and ion exchange chromatography confirmed the presence of only one molecular form of hexokinase in this muscle. A procedure for purifying hexokinase from Ascaris muscle has been developed. The physical and catalytic properties of the enzyme are comparable to mammalian hexokinases. The enzyme is a monomer with a molecular weight of 100,000 as det… more
Date: August 1975
Creator: Supowit, Scott C.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effect of Inorganic Phosphate on the Morphology and Poly-β-Hydroxybutyrate Content of Azotobacter Vinelandii Atcc 12837

Description: This study was designed to determine the effect of inorganic phosphate in the growth media of A. vinelandii on the synthesis and accumulation of poly-β-hydroxybutyrate (PHB) and cellular morphology. Burk's media with no added phosphate and ten times normal phosphate resulted in altered cells, lower levels of protein, and decreased cell populations. PHB accumulation was much higher in the cultures with no added phosphate; however, the polymer granules differed in appearance from those of normal … more
Date: May 1975
Creator: Collins, Patricia Ann
Item Type: Refine your search to only Thesis or Dissertation
open access

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… more
Date: December 1974
Creator: Smith, Jackson Kelly
Item Type: Refine your search to only Thesis or Dissertation
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Effect of Light and Other Environmental Factors on Growth and Carotenogenesis of Corynebacterium Species Strain 7E1C

Description: This investigation studies effects of environmental factors on growth and carotenogenesis in Corynebacterium strain 7ElC. Changes in pH were found to effect growth more than carotenogenesis. However, certain nutrients or long incubation periods stimulated carotenoid formation more than growth. Dark conditions in a mineral salts-glucose medium stimulated growth, but minimized carotenogenesis. Tryptic soy broth or yeast extract elicited carotenogenesis in darkness. Although brief light exposure d… more
Date: August 1974
Creator: Howard, Marta E.
Item Type: Refine your search to only Thesis or Dissertation
open access

The Population Dynamics and Trophic Relationships of Seven Species of Fish in a Small Southwestern Pond, with Special Attention Toward Young-of-the-Year Fish

Description: Production rates of seven species of fish, along with food-web interactions, were determined for one year in a pond. Production of fish in the pond amounted to 208.9 q/m2/yr. Over 95% of the production occurred in the summer, with Y of Y fish contributing 83.8%. There were two food-web interactions observed in Y of Y fishes: crappie vs. bass and bullhead vs. sunfish. When Y of Y fish shifted to benthic diets in the spring, the small biomass of benthos available could not sustain the larger bio… more
Date: August 1975
Creator: Jones, Fredrick V.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effects of an Acute Bout of Near-Maximal Intensity Exercise on the Cardiac Enzymes in Human Sera

Description: The Cardiac Profile, a pattern of serum enzyme changes seen within seventy-two hours after an AMI, is diagnostic aid for detecting occurrence of infarcts. The effects of exercise stress on the Cardiac Profile aid clinicians in avoiding diagnostic errors in patients immediately after exercise. Five male volunteers ran from six to ten miles. Serum enzyme levels were monitored serially three days before and five days after stress. Enzyme activity was determined spectrophotometrically and electroph… more
Date: May 1979
Creator: Goheen, Bernadette A.
Item Type: Refine your search to only Thesis or Dissertation
open access

Pharmacological, Temperature, and Electrogram Studies on the Posterior Lymph Heart of the Bullfrog

Description: In view of the discrepancies and conflicts produced by previous studies on amphibian lymph hearts, a study was initiated to reinvestigate the pharmacological, temperature, and electrical aspects of lymph heart physiology. Bullfrogs were chosen as the experimental animal, All lymph heart responses to experimentation were physiographically recorded as myograms and electrograms. The results are in agreement with previous studies on some aspects and in conflict on others. From the results obtained,… more
Date: May 1975
Creator: Oberndorfer, Carol E.
Item Type: Refine your search to only Thesis or Dissertation
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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 reser… more
Date: December 1976
Creator: Sams, Barry L.
Item Type: Refine your search to only Thesis or Dissertation
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X-irradiation Effects on the Action Potentials of Frog Sciatic Nerves Inhibited by Carbon Monoxide and Ouabain

Description: The response of frog sciatic nerve action potentials to x-irradiation and metabolic (carbon monoxide) or transport (ouabain) inhibition was determined in an attempt to further identify the nature of radiation insult to nervous tissue. Carbon monoxide, ouabain (2 X 10-5 M), and nitrogen anoxia were shown to produce a near linear decline in action potential amplitude. The carbon monoxide and nitrogen inhibitions of activity were reversible in air; the carbon monoxide inhibition was light reversib… more
Date: December 1971
Creator: Thompson, Wesley J.
Item Type: Refine your search to only Thesis or Dissertation
open access

Induction of 16α Hydroxylase in Human Cultured Lymphocytes

Description: A method is presented for 160hydroxylase (SAH) induction in cultured human lymphocytes. SAH, a microsomal-associated enzyme, effects the oxidative conversion of 17pestradiol to estriol, which competes for cytoplasmic binding sites. 17,-estradiol and estrone are known mammary carcinogens, while estriol and its epimers have been suggested to have anticarcinogenic properties. To substantiate genetic variations of hydroxylase activity, an analysis of estrogen-induced cultured human lymphocytes was … more
Date: December 1975
Creator: Muijsson, Ingrid E.
Item Type: Refine your search to only Thesis or Dissertation
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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 th… more
Date: December 1975
Creator: Nejtek, Michael E.
Item Type: Refine your search to only Thesis or Dissertation
open access

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 Platea… more
Date: May 1975
Creator: Szczytko, Stanley W.
Item Type: Refine your search to only Thesis or Dissertation
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