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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Augalų atsparumas abiotiniams veiksniams / Plant resistance to abiotic factors

Spalinskas, Rapolas 25 November 2010 (has links)
Viena svarbiausių augalų genetikos problemų yra jų atsparumas abiotiniams veiksniams. Tokie veiksniai kaip šaltis, ozonas ar ultravioletinė spinduliuotė sukelia oksidacinį stresą ir ROS formavimąsi augalų ląstelėse. Visi augalai turi antioksidantines sistemas, vykdančias ROS detoksikaciją. Žalioji kreisvė (Crepis capillaris L.(Wallr.)) ir atsparūs šalnoms bulvių somatiniai asimetriniai hibridai buvo tiriami atsparumui abiotiniams veiksniams, įvertinant morfometrinius, biocheminius ir genetinius rodiklius po UV-B –(2, 4, 8 kJ/m2) ir ozono (40 ir 80 ppb) poveikio. Nustatyta, kad jautrūs stresiniams veiksniams yra morfometriniai parametrai- žalia ir sausa biomasė, lapų plotas ir skaičius. Biocheminiai parametrai, tirpių baltymų kiekis ir antioksidantinio fermento superoksido dismutazės (SOD) aktyvumas, tirtuose augaluose proporcingai didėjo priklausomai nuo dozės dydžio. Padidėjęs antioksidantinio SOD fermento aktyvumas po abiotinių veiksnių poveikio vertintinas kaip augalo adaptacinis atsakas į UV-B sukeltą oksidacinį stresą. Tiriant atsparumą šalčiui nustatyta, kad atsparus šalčiui bulvių hibridas H269, įgijo iš donoro Solanum commersonii DNR fragmentą, susijusį su padidinta mitochondrijų elektronų pernašos sistemos genų raiška, kuri siejama ROS koncentracijos reguliavimu ląstelėje ir šalčio atsako genų reguliavimu branduoliniame genome. Parodėme, kad atsparumai abiotiniams veiksniams- ozonui, UV-B ir šalčiui augaluose funkcionuoja kaip vientisa gynybos sistema, apimanti... [toliau žr. visą tekstą] / One of the major issues of plant genetics is their tolerance and resistance to abiotic factors. Low temperatures, ozone and ultraviolet radiation are the factors that increase ROS formation and oxidative stress in a plant cell. All plants have effective antioxidant systems to detoxify ROS. Researches were carried out to evaluate the resistance of Smooth Hawksbeard (Crepis capillaris L. (Wallr)) and frost resistant asymmetric somatic potato hybrids to abiotic stresses, estimating the morphometrical, biochemical and genetic data after treating the plants with UV-B (2, 4, 8 kJ/m2) and ozone (40 ir 80 ppb) doses. Test data shows, that morphometrical parameters such as fresh and dry weight along with leaf area and count are very sensitive to stress factors. Biochemical parameters such as soluble protein content and the activity of antioxidant enzyme superoxide dismutase (SOD) have risen pro rata from the dose given. The increment of SOD after treating the plants with simulated abiotic factors is annotated as adaptation to UV-B stress. Analysis of the cold acclimation has shown, that potato hybrid H269 has gained DNA fragment from the donor species Solanum commersonii. This fragment is associated with over-expressed genes of mitochondrial electron transfer system which regulates the concentration of ROS in the cell and controls the expression of nuclear genes related with cold-acclimation. With this analysis we have showed that plant resistance to abiotic factors such as ozone... [to full text]
22

Stoffwechseluntersuchung bei klinisch gesunden Kühen unter besonderer Berücksichtigung der Superoxid-Dismutase

Zahn, Nadine 29 May 2006 (has links) (PDF)
Seit Anfang der Siebzigerjahre werden weltweit in Rinderbetrieben in vielfältigen Variationen und Anwendungen Stoffwechseluntersuchungen durchgeführt. Das Hauptaugenmerk lag dabei stets auf Seiten der Energie- und Mineralstoffversorgung. Die Superoxid-Dismutase (SOD) fand hier bislang keine Berücksichtigung. Ziel der vorliegenden Untersuchung war es, die SOD-Aktivität in Stoffwechsel-untersuchungen bei klinisch gesunden Kühen mit ein zu beziehen sowie den Einfluss von Laktation und Jahreszeit zu prüfen. Versuchsanordnung: Insgesamt wurden bei 125 SB/HF-Kühen (7990 kg fettkorregierte Milch/Jahr) folgende drei Gruppen analysiert: Gruppe 1: Im Verlauf eines Jahres wurden im Abstand von 6 Wochen jeweils 10 gesunde Kühe, die sich alle 1-2 Wochen post partum (pp) befanden, untersucht. Zusätzlich wurden die Stall- und die Außentemperaturen berücksichtigt. Gruppe 2: Zur Kontrolle des Laktationsverlaufes wurden 10 Kühe zum Zeitpunkt 4-5 Wochen ante partum (ap), 1 Woche ap, 1-2 Wochen pp, 4 Wochen pp und 8-12 Wochen pp untersucht. Gruppe 3: Um jahreszeitlich bedingte Schwankungen des Stoffwechsels und der SOD-Aktivität in Gruppe 2 auszuschließen, wurden an einem Entnahmetag jeweils sieben verschiedene Kühe zum Zeitpunkt 4-5 Wochen ap, 1 Woche ap, 1-2 Wochen pp, 4 Wochen pp, und 8-12 Wochen pp geprüft. Die Tiere aller drei Gruppen wurden nach der klinischen Untersuchung hämatologisch sowie klinisch-chemisch (SOD, β-Hydroxybutyrat (BHB), Glucose, Cholesterol, Bilirubin, Glutamat-Dehydrogenase (GLDH), Aspartat-aminotransferase (ASAT), Creatinkinase (CK), Protein, Albumin, Harnstoff, Calcium, anorganisches Phosphat, Magnesium, Natrium, Kalium, Chlorid, Eisen) getestet. Auch die Fütterung fand durch Anfertigung einer Rationsberechnung Berücksichtigung. Ergebnisse: Die Ergebnisse der Stoffwechseluntersuchungen und der SOD-Aktivität im Jahresverlauf (Gruppe 1) deuten auf eine verminderte Futteraufnahme in den Sommermonaten infolge Hitzestresses hin. Vor allem ein Absinken der Harnstoff-, Glucose- (positive Korrelation zur SOD-Aktivität), Phosphat- (positive Korrelation zur SOD-Aktivität) und Cholesterolkonzentrationen bei gleichzeitig ansteigenden BHB- (negative Korrelation zur SOD-Aktivität) und Bilirubinkonzentrationen weisen auf eine negative Energiebilanz in diesen Monaten hin. Die Calcium- und Magnesiumkonzentrationen liegen bei allen Tieren im unteren Referenzbereich. Die SOD-Aktivität klinisch gesunder Kühe im Jahresverlauf beträgt 501 bis 978 U/ml Erythrozytenlysat (Interzentilbereich). In Gruppen 2 und Gruppe 3 sind ebenfalls deutliche Schwankungen der Stoffwechselparameter Protein, Harnstoff, Bilirubin, Glucose, BHB und Cholesterol zu beobachten, wobei die stärksten Schwankungen im Zeitraum 1 Woche ap bis 4 Wochen pp vorhanden sind. Auch dies ist durch die reduzierte Futteraufnahme peripartal sowie steigende Futteraufnahme in der Frühlaktation zu erklären. Die SOD-Aktivität der Kühe aus Gruppe 2 zeigt die entsprechenden Schwankungen mit niedrigen Aktivitäten 4-5 Wochen ap bis 1-2 Wochen pp und einen deutlichen Anstieg bis 4 Wochen pp. Die Calcium- und Magnesiumkonzentrationen befinden sich auch in dieser Gruppe im unteren Referenzbereich. In der Gruppe 3 fällt bei den Kühen 4 Wochen pp eine deutliche Stoffwechselbelastung mit erhöhten Bilirubin- und BHB-Konzentrationen sowie ASAT- und GLDH-Aktivitäten auf. In dieser Gruppe sind die Calcium- und Magnesiumkonzentrationen physiologisch. Die SOD-Aktivitäten differieren nur gering mit einer tendenziell höheren Aktivität 4 Wochen pp. Insgesamt fallen im Vergleich zu Gruppe 1 und 2 deutlich höhere SOD-Aktivitäten zwischen 835 und 1758 U/ml Erythrozytenlysat (Interzentilbereich) auf, welche mit den höheren Calcium- und Magnesiumkonzentrationen in Beziehung stehen können. Schlussfolgerungen: Schwankungen von Stoffwechselparametern im Jahres- und Laktationsverlauf betreffen vor allem fütterungsabhängige Parameter. Die SOD-Aktivität verhält sich entsprechend dieser fütterungsabhängigen Parameter mit niedrigerer Aktivität bei längeren Belastungsphasen sowie im geburtsnahen Zeitraum. Statistisch gesicherte Korrelationen ergaben sich mit folgenden fütterungs-abhängigen Parametern: im Jahresverlauf mit BHB, Glucose und anorganischem Phosphat, im Laktationsverlauf in Gruppe 2 mit BHB, Cholesterol, Protein, Glucose, Magnesium und Milchharnstoff und in Gruppe 3 zu BHB und Magnesium. Die Analyse der SOD-Aktivität bereichert die Informationen bei Stoffwechselkontrollen sinnvoll.
23

A study of the activity and characteristics of superoxide dismutase in the male reproductive parts of petunia

Moon, Bok Hee January 2006 (has links)
In the stamen (male reproductive tissue) of petunia 'Hurrah' flowers, the occurrence of SOD (superoxide dismutase) provided an effective anti-oxidative mechanism against superoxide production. Superoxide production and SOD activities at five developmental stages showed a positive correlation. The highest superoxide production and SOD activity in different parts of the stamen (anther, filament and pollen) were at stages with high metabolic activity: (i) during growing buds (in anthers and filaments) (ii) when flowers with predehiscent anthers were fully open (in pollen). In all parts of the stamen, SOD activity was the lowest at stage five (fully open flowers with dehiscent anthers), superoxide production was also lower at this stage with the exception of the pollen. The highest SOD activity was localized in anthers with the pollen, suggesting that the filaments only have a structural support function. SOD was examined on a native PAGE with regard to the isozymes present within the stamen of five developmental stages. Three isozymes, which were identified as Mn SOD, Fe SOD and Cu/Zn SOD by reactions with inhibitors, were commonly found at five developmental stages in crude extracts of anthers, filaments and pollen. The developmental stages with stronger isozyme bands on the native PAGE were consistent with the stages with higher SOD activities, and the Mn SOD and Fe SOD isozyme bands were more intense than Cu/Zn SOD bands, suggesting the activities of Mn SOD and Fe SOD in the crude extracts were much higher than Cu/Zn SOD. SOD from 1,000 stamens of dehiscent mature flowers was partially purified using ammonium sulphate fractionation and DEAE cellulose column chromatography. The purified bound fraction contained only one SOD isozyme on a native PAGE, which was shown to be a Mn SOD, as it is sensitive to neither hydrogen peroxide nor cyanide. The specific activity of the purified SOD was 66.5 U/mg and the yield of total activity was 3.0%. The progress of enzyme purification was monitored using SDS-PAGE and the bound fraction contained two major polypeptide bands. The purified enzyme activity was optimal in the range of neutral pH, but it was the highest at pH 7.8. Through incubation at various pH levels for 24 hours, favourable stability of the purified fraction was confirmed around a pH range of 7 to 8.5. The purified enzyme retained 87% of its initial activity at -20 ? after one month of storage, but at 4 ? only 38% of the initial activity remained after the same period of storage.
24

Occurrence and Charactrisation of Superoxide Dismutases in the Female Reproductive Structures of Petunia

YeYing Wang, Ying January 2006 (has links)
Superoxide Dismutase (SOD) activity in cell-free extracts prepared from healthy mature flowers of Petunia hybrida (variety 'Hurrah') was studied. The SOD activity in the crude extracts was stable for more than one month when stored at -20 oC. It was found that pH 7.8 is optimal for SOD activity. Different flower tissues of petunia (stigma, style and ovary) at various stages of development were extracted and analysed for SOD activity. SOD activity was found to be significantly highest in the ovary tissue of dehiscent petunia flowers. Three SOD isozymes were detected after crude extracts of the different female reproductive tissues of petunia flowers were analysed on a non-denaturing polyacrylamide gel electrophoresis system. Based on a difference in the sensitivity of the SOD isoforms to H2O2 and KCN, it is suggested that Mn-SOD, Fe-SOD and Cu/Zn-SOD were present in the crude extracts of the female reproductive tissues of petunia flowers. The response of the female reproductive parts of petunia flowers was also tested under water deficiency and high temperature (35 oC) stress. The SOD activity seemed to increase more in response to the high temperature than the water deficiency stress. Intense blue staining was observed from developing younger buds, and much lower formazan deposition was detected at the later stage. This indicates the lower O2- produced during later stages mainly due to increasing SOD synthesis. DEAE cellulose chromatography was successfully used to partially purify SOD from the ovaries of petunia flowers. The characteristics of the partially purified enzyme fraction were found to be very similar to those of the crude extracts.
25

Účinnost specifických aditiv ve výživě sportovních koní

Hanzlíková, Michaela January 2014 (has links)
This thesis deals with the use of specific additives in the diet of sport horses. The theme is focused on the peppermint, and its antioxidant activity in horses. There is experiment conducted in 6 different horses to race, sex and age on antioxidant activity of superoxide dismutase SOD and GPx glutathione peroxidase. During the experiment was 4x took blood sample of horses to determine the activity of antioxidant enzymes in period of feeding without additives and feeding with activity use of additives in the diet. The results of experimental monitoring the activity of SOD, as well as in monitoring the activity of GPx enzyme revealed large individual differences between individual animals, which is typical for horses. In our attempt at SOD activity has not been demonstrated statistical relevance. Conversely, it was with the activity of glutathione, here, the results were statistically significant (P <0.05).
26

The effects of photosymbiosis on gene expression in the facultatively symbiotic coral Astrangia poculata, with a focus on NF-kappaB signaling and antioxidant enzymes

Nguyen, Linda 09 November 2020 (has links)
Corals are critical to marine biodiversity and human welfare. Coral reefs cover <1% of the seafloor but support ~1/3 of all marine species. Approximately 1.5 billion people live within 100 km of coral reefs, relying upon them for food, income from tourism, and protection from storms. Their economic value has been estimated at $375 billion annually. The foundation of coral reefs is the intracellular symbiosis between corals and photosynthetic dinoflagellates of the family Symbiodiniaceae. Tropical corals satisfy up to 95% of their nutritional requirements through photosynthesis, and their ability to construct reefs is biochemically coupled to photosynthesis. While permitting corals to thrive, photosymbiosis also increases their exposure to environmental stressors and vulnerability to climate change. Reliance on photosynthesis restricts reef-building corals to shallow, clear, tropical waters, where they experience higher temperatures and UV exposure. The generation of reactive oxygen species by the symbiont also exposes corals to greater oxidative stress. The symbiosis is particularly sensitive to climate change: all of the mass coral bleaching events have occurred since 1982, driven by elevated ocean temperatures. Molecular cross-talk between host and symbiont impacts resilience of the coral holobiont and resistance to bleaching. Unfortunately, we know little about how photosymbiosis impacts expression or activity of coral genes. Tropical corals engage in an obligate symbiosis with Symbiodiniaceae, so we cannot study their gene expression in a stable aposymbiotic state. However, the northern star coral, Astrangia poculata, engages in a facultative symbiosis with Symbiodiniaceae. I used RNA sequencing to investigate how symbiosis impacts gene expression in A. poculata, focusing on genes implicated in photosymbiosis: antioxidant enzymes (specifically superoxide dismutases) and the NF-κB signaling pathway. From an improved transcriptome assembly, I recovered core elements of a primitively simple NF-κB signaling pathway and a rich complement of SOD proteins. 273 coral transcripts—many associated with protein metabolism and vesicle-mediated transport— were differentially expressed in symbiotic versus aposymbiotic corals. Unlike in the facultatively symbiotic sea anemone Exaiptasia, symbiosis was not associated with depressed NF-κB transcript levels. IKKε, a potential positive regulator of NF-κB activity, was strongly up-regulated, as was one particular superoxide dismutase.
27

Identification of Acid Volatile Sulfides as a Predictor of Sediment Oxygen Demand and Comparison of the Degree of Pyritization between Weeks Bay, AL and Old Tampa Bay, FL

Anderson, Erin Leigh 17 August 2013 (has links)
Weeks Bay, AL is a governmentally protected reserve near Mobile Bay, AL, while Old Tampa Bay, FL is an urbanized estuary, located along the western coast of Florida. Estuary health is important to local economies and the health of local marine life, with an emphasis on low levels of eutrophication. Sediment oxygen demand (SOD) is usually measured to qualify the environmental health of estuaries, but SOD is timeconsuming and expensive. Average acid volatile monosulfides (AVS) concentrations were found to accurately predict SOD variances. The Degree of Pyritization (DOP) is a measure of long-term sediment oxidation conditions, which indicates normal estuary state. Despite the urban land use practices of these two bays, the DOP of each bay is similar.
28

Free Radical Scavenging Properties of Cerium Oxice Nanoparticles

Korsvik, Cassandra 01 January 2007 (has links)
Ceria is a lanthanide series element that can exist as Ce3+ or Ce4+. Cerium oxide nanostructures are being developed for use in industry as catalysts. Nanostructures often behave differently from their corresponding macrostructures and these new behaviors can result in novel and important biological and chemical properties. The free radical theory of aging suggests that free radicals many of which are reactive oxygen species, damage cellular macromolecules. This damage can contribute to degenerative diseases, cancer and aging. Recent research has shown that ceria oxide nanoparticles protected cells from UV and radiation damage as well as decrease intracellular reactive oxygen species in primary cell cultures. The enzyme superoxide dismutase (SOD) protects the cell from free radicals by reacting with superoxide, a reactive oxygen species. Chemicals that catalyze the same reaction as SOD are referred to as SOD mimetics. Another biologically significant free radical is nitric oxide, a reactive nitrogen species. Nitric oxide is an important signaling molecule in both the cardiovascular and nervous system; however it can also cause damage to proteins through nitrosylation. When superoxide and nitric oxide react with each other they form the highly potent free radical, peroxynitrite. This reaction naturally occurs in the phagolysosome of the macrophage and is utilized by the immune system to kill pathogens. Nanoceria was tested for activity against superoxide, nitric oxide and peroxynitrite. The results presented in this work show that ceria oxide nanoparticles exhibit SOD mimetic activity and reduce protein nitrosylation in vitro.
29

Sediment Oxygen Demand in the Central Basin of Lake Erie

Smith, Derek January 2008 (has links)
No description available.
30

Evaluation of the Aging Immune System Using a Mouse Model of Brucella Infection

Prasad, Rajeev 16 December 2008 (has links)
Aging is accompanied by dysregulated immune function resulting in increased susceptibility of the elderly to diseases caused by microbial pathogens. There exists a multitude of data suggesting decreased resistance of the elderly to a variety of intracellular pathogens but there is no data relating the effect of aging on the immune response against Brucella. To elucidate the mechanism of immune dysregulation in old, old and young DBA/2 and BALB/c mice were infected with wild-type B. abortus strain 2308. The old and young mice were also vaccinated with vaccine B. abortus strain RB51 over-expressing Cu-Zn superoxide dismutase (SOD) and then challenged with B. abortus strain 2308 to determine the effect of vaccination in old vs. young mice. Specific IgG1 and IgG2a response to Brucella antigens were also evaluated to determine the effect of aging on Th-specificity of the immune response against Brucella infection. The immune response in aged vs. young mice was further assessed using RT-PCR and cytokine antibody array to determine the type of T-helper response. The experimental results indicate that all mice, regardless of age, survived infection ranging from doses of 2 x 104 to - 2 x 108 CFU. Though the older DBA/2 mice had a higher organism burden after 1 week of infection, these mice cleared Brucella infection more efficiently (5 weeks post-infection) than young mice. Vaccination with strain RB51 over-expressing SOD provided significant protection in young DBA/2, young BALB/c and old BALB/c mice but not in old DBA/2 mice after strain 2308 challenge. The results also suggest that old mice produced a different magnitude of IgG1 and IgG2a response to bacterioferritin and SOD of Brucella. The data suggests that both Th17 as well as Th1 responses were accentuated in old mice as compared to young mice following infection with Brucella. How the Th17 and Th1 branches of immune system work together enabling old mice to clear Brucella better than young mice warrants future investigation. / Master of Science

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