viii, 96 leaves : ill. ; 28 cm Typescript. (Another copy on microfilm is located in Archives) Thesis (M.S.)--University of Oregon Includes vita and abstract Bibliography: leaves 91-96 University of Oregon theses, Dept. of Biology, M.S., 1979

ix, 85 leaves : ill. ; 28 cm Typescript. (Another copy on microfilm is located in Archives) Thesis (M.S.) -- University of Oregon Includes vita and abstract Bibliography: leaves 82-85 University of Oregon theses, Dept. of Biology, M.S., 1979

ix, 73 leaves : ill. ; 28 cm Typescript. (Another copy on microfilm is located in Archives) Thesis (M.S.) -- University of Oregon Includes vita and abstract Bibliography: leaves 69-73 University of Oregon theses, Dept. of Biology, M.S., 1980

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Made available in DSpace on 2014-06-11T19:32:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2001Bitstream added on 2014-06-13T19:42:37Z : No. of bitstreams: 1 hokama_nk_dr_botfm.pdf: 442709 bytes, checksum: 19c729c7bb99de9b488b0c496f8b3922 (MD5) / A hemoglobina, o componente principal do citoplasma eritrocitário, está sujeita à oxidação, fisiologicamente ou por agentes externos, seja através da formação de Metahemoglobina, ou pela oxidação da cisteína β93 por agentes tiois. Impossibilitado de sintetizar proteína, o eritrócito depende primordialmente da via glicolítica, que, além de fornecer ATP, através da integração da formação de NADH e da Via da Hexose Monofosfato, mantém o potencial redutor extremamente eficiente. A presente investigação teve como finalidade avaliar o sistema de óxido-redução eritrocitário, à partir da oxidação da hemoglobina pelas seguintes drogas: a) Nitrito de Sódio, indutora da formação de Metahemoglobina; b) Azul de Metileno, utilizado terapeuticamente e em testes laboratoriais na redução de Metahemoglobina; c) Cistamina, agente tiol, que induz à formação do complexo Hemoglobina-Etilamina, através da oxidação da cisteína β93. Doadores de sangue da Divisão Hemocentro foram convidados a participar do trabalho e tiverem seu sangue coletado após consentimento - 96 - verbal e por escrito. Todos os indivíduos eram do sexo masculino, não anêmicos e sem deficiência de G6PD. Foram utilizados, para os testes, glóbulos lavados, ressuspensos em PBS, pH 7.45, com hemoglobina ajustada entre 11 e 13 g/dl, na presença de glicose e incubados a 37o C com as drogas testadas, nos momentos 10. 90 e 180 minutos de incubação... / Hemoglobin, the essential component of erythrocyte cytoplasm, is physiologically prone to oxidation by external agents, through the formation of Methemoglobin or the oxidation of β93 cysteine by thiol agents. Unable to protein synthesis, the erythrocyte depends essentially on glycolysis, which, besides producing ATP, maintains the highly efficient reduction potential through the integration of NADH production and the Hexose Monophosphate Shunt. The present investigation’s purpose was to evaluate the erythrocyte antioxidant system by studying hemoglobin oxidation by the following substances: a) Sodium Nitrite (SN), a well known Methemoglobin-forming agent; b) Methylene Blue (MB), a Methemoglobin reductant reagent, available for therapeutic and laboratory tests; c) the thiol reagent Cystamine (CI), that reacts with hemoglobin through the β93 cysteine oxidation, forming the Hemoglobin-Ethylamine complex. After informed... (Complete abstract click electronic access below)

A comparative phylogenetically independent contrast (PIC) analysis was employed to investigate the adaptive role of traits involved in hypoxia tolerance in sculpins, a group of closely related fish species that live in the nearshore marine environment. I demonstrated that there was a tight correlation between critical oxygen (O₂) tension (P-crit) and the distribution of species across an environmental gradient. Species of sculpins with the lowest P-crit inhabit the 0₂ variable intertidal zone, while species with higher P-crit inhabit the O₂ stable subtidal zone. Low P-crit values in sculpins were associated with enhanced O₂ extraction capacity, with three principal traits accounting for 83% of the variation in P-crit: low routine O₂ consumption rate (MO2 ), high mass specific gill surface area and high whole cell hemoglobin-oxygen (Hb-0₂) binding affinity. Variation in whole cell Hb-O₂ binding affinity was strongly correlated with the intrinsic affinity of Hb for O₂ and not to differences in the concentration of the allosteric Hb modulators ATP and GTP. When environmental O₂ dropped below a species' P-crit, some species of sculpins behaviorally responded to the severe hypoxia by performing aquatic surface respiration (ASR) and aerial emergence. Although intertidal sculpins consistently performed these behaviors, the clustering of these species into a single phylogenetic Glade did not allow us to draw conclusions regarding the relationship between ASR, aerial emergence and P-crit using PIC analysis. Three species of sculpins, which were chosen because of their low, medium and high P-crit values, exhibited dramatically varied mortality rates when exposed to severe hypoxia equivalent to 40% of their respective P-crit. Although ATP turnover rates were similar between the three species in the initial two hours of hypoxia exposure, the differences in the ability of the three species to survive severe hypoxia appeared to be associated with the concentration of on-board liver glycogen and the degree of liver glycogen depletion. However, when liver glycogen was assessed in twelve species of sculpins at normoxia and compared with P-crit, there was nosignificant PIC correlation between P-crit and liver glycogen. Overall, I have shown that there is a clear relationship between P-crit and the distribution of sculpins along the nearshore environment and that this is primarily related to differences in O₂ extraction capacity. When O₂ tensions are well below their P-crit, there are dramatic differences in behavioral, physiological and biochemical responses among these species of sculpins. / Science, Faculty of / Zoology, Department of / Graduate

Studies were conducted to determine the onto genetic changes in the number and relative concentration of the electrophoretically distinguishable hemoglobin polymorphs of coho salmon, Oncorhynchus kisutoh and the influence of certain environmental factors upon the expression of the hemoglobin variants. In addition some of the oxygen equilibrium characteristics of the hemoglobin of freshwater fry and adult coho were investigated using both hemolyzates and whole blood. Throughout the life cycle of coho salmon seventeen to nineteen distinct hemoglobin components were identified in micro-starch-gel electropherograms prepared in borate buffer at pH 8.5. These components formed three main electrophoretic hemoglobin patterns associated with different stages of the life cycle. Unhatched embryos and alevins possessed twelve anodic and one cathodic components. All except three anodic components had disappeared from the blood of free-swimming fry fourteen weeks after hatching. This three-component pattern was retained until the beginning of the presmolt period, approximately eleven months after hatching. At this stage, five new cathodic components, one new anodic component and one anodic component which had previously been visible in alevin electropherograms appeared. In presmolts and smolts these additional seven components accounted for less than 20 % of the total hemoglobin of the blood while the three components observed in fry blood accounted for the remainder. Following migration to sea water the relative concentration of these seven components gradually increased to 45 to 50% of the hemoglobin over a two-month period. No further change in either the number or relative concentrations of the hemoglobin components was observed during the remaining phases of the life cycle. Since it was apparent that changes in hemoglobin pattern were temporally associated with changes in the characteristics of the environment occupied by the juvenile coho the effects of water temperature, dissolved oxygen concentration and salinity upon the physical development and electro-phoretic hemoglobin pattern of underyearling coho were examined. Exposure to freshwater temperatures of 1.4 to 15.0 C, dissolved oxygen concentrations of 2.2 to 9.7 ppm and salinities of 0 to 30 °/oo for periods of 49 to 60 days had no influence upon the electrophoretic hemoglobin pattern of either 3 1/2-month-old fry or 11-month-old presmolts. Presmolts reared for 60 days in freshwater at 15 C and in 10 °/oo salinity at 9.2 C grew at a highly accelerated rate and were equal or greater in size than 16 1/2-month-old postsmolts which had been residing in sea water for one month. These large presmolts retained the hemoglobin pattern characteristic of normal presmolts of the same age. Postsmolts maintained in aerated freshwater rather than sea water underwent changes in the electrophoretic hemoglobin pattern characteristic of sea-water residents. The foregoing observations suggest that age rather than physical size or environmental factors is the main determinant in the expression of the polymorphic hemoglobins of coho salmon. The oxygen equilibrium characteristics of adult coho hemoglobin and hemoglobin components A6-8 (fry hemoglobin) isolated from adult hemolyzates by ion-exchange chromatography were investigated. Adenosine triphosphate concentrations ranging from 0.0 to 0.76 moles/mole hemoglobin had no influence upon the oxygen equilibrium of adult hemolyzates whereas at a concentration of 7.56 moles/mole P₅₀ increased by 1 to 2 mm Hg. Since erythrocyte ATP concentrations of freshwater adult coho ranged between 0.8 and 1.3 moles/mole hemoglobin this organic phosphate is probably not a modifier of oxygen affinity in coho salmon. The hemoglobin of adult coho was relatively insensitive to variations in pH and temperature with ∅ =-0.172 at 9.8 C over the pH range of 6.95 to 8.20 and Δ log P₅₀ = 0.019 between 5 and 15 C. The Bohr effect of fry hemoglobin was nonlinear so that ∅ = -0.033, -1.729 and -0.182 in the pH ranges of 6.82 to 7.08, 7.08 to 7.50 and 7.50 to 8.50, respectively. The estimate of Δ log P₅₀ was 0.056 for fry hemoglobin. Thus at 9.8 C the oxygen affinity of fry hemoglobin exceeded that of adult hemoglobin at pH greater than 7.3 but was lower at values of pH less than 7.3. At pH 7.4, the P₅₀ of fry and adult coho hemoglobin was 8.4 and 17.9, respectively. In neither case was a Root effect observed. Heme-heme interaction was similar for both adult and fry hemoglobin and the value of n always exceeded 1.0. The estimate of n was generally less than 2.0 at pH greater than 7.0 and tended to decrease as the pH or the equilibration temperature increased. Studies with fry and adult whole blood equilibrated With 0.2 and 3.4 mm Hg of carbon dioxide generally confirmed the qualitative differences observed between the oxygen equilibria of fry and adult hemolyzates. The estimates of P₅₀ at 9.3 C and PCO₂ of 0.2 and 3.4 mm Hg were 5.5 and 12.5 mm Hg respectively for fry blood and 10.7 and 15.6 mm Hg, respectively, for the blood of freshwater adults. / Science, Faculty of / Zoology, Department of / Graduate

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Investigations of the nitrogen fixing (nif) genes in the cyanobacterium Nostoc commune UTEX 584 revealed a gene encoding a hemoprotein, named cyanoglobin. The cyanoglobin gene was isolated and subcloned into Escherichia coli previously. Cyanoglobin possesses a high oxygen affinity. The study presented here investigated the functional role of cyanoglobin, and encompassed the determination of the kinetic basis for the high oxygen affinity of cyanoglobin through kinetic studies utilizing stopped-flow spectrophotometry and flash photolysis. In addition, studies of cyanoglobin, in the presence of a variety of ligands, employed as structural probes of the distal pocket architecture, are presented. These data are interpreted in terms of structural models of cyanoglobin produced by homology modelling and hemoglobins with known crystal structures. Cyanoglobin coordinated oxygen and a variety of ligands with high rates of association, which explained the high oxygen affinity of cyanoglobin. Cyanoglobin possessed high rates of autoxidation and hemin loss. The ligand binding behavior of cyanoglobin was more similar to leghemoglobin than to sperm whale myoglobin. The ligand binding behavior of cyanoglobin is explained in terms of a highly reactive, and solvent exposed, heme-iron. The 5' region of glbN interacted with NtcA, the global regulator of nitrogen metabolism in cyanobacteria, which may provide an indication of the nitrogen deprivation signal required for cyanoglobin expression in vivo. Finally, the isolation and N-terminal sequencing of a potential cyanoglobin homolog in Anabaena sp. strain PCC 7120 is presented. Collectively, the data obtained in this study may support the model of cyanoglobin function described by Hill, et al., that cyanoglobin sequesters oxygen, and presents it to, or is a part of, a terminal cytochrome oxidase complex in Nostoc commune UTEX 584 under microaerobic conditions, when nitrogen fixation, and thus ATP demand, is maximal. / Ph. D.