Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to determine the intensity of Ichthyophthirius multifiliis infection, as well as net ion fluxes (Na+, K+ and Cl-), in silver catfish juveniles exposed to different pHs (5, 6, 7, 8, and 9 for sixteen days), pH (5.0 and 7.0) and hardness (20, 60 and 120 mg CaCO3.L-1 for sixteen days) and the oxidative stress parameters in liver, gill and muscle of this species and submitted to different pH (5.0 and 7.0 for three days). Net Na+, K+, and Cl- fluxes were determined at different times, trophonts in the skin and gill were counted, and mortality was registered daily. After six days fish kept at pH 6.0, 7.0, 8.0 and 9.0-hardness 20 mg CaCO3.L-1 showed significantly higher cumulative mortality (100% after eight days) and number of trophonts on the skin and gill compared to pH 5.0-hardness 20 mg CaCO3.L-1. Infected silver catfish showed significantly higher Na+ and K+ effluxes in the first day, and there was a recovery (influx) after the second day compared to asymptomatic juveniles. Silver catfish juveniles infected with I.multifiliis and exposed to pHs 5.0 and 7.0 presented significantly higher TBARS levels in the liver and gills compared to asymptomatic juveniles. The activity of catalase in the liver of silver catfish juveniles infected and exposed to both pHs was significantly lower (1st and 3rd day) than in asymptomatic juveniles. The GST activity in the liver and gills of infected juveniles increased throughout all experimental period compared to asymptomatic juveniles. The muscle of infected juveniles maintained at pH 5.0 showed significantly lower TBARS levels at day three compared to asymptomatic juveniles. The CAT activity was significantly lower in the muscle of infected juveniles at pH 5.0 and 7.0 at all experimental days except day 1 at pH 7.0 compared to asymptomatic juveniles. The muscle of infected juveniles presented significantly lower GST activity in all experimental period at both pH 5.0 and 7.0 compared to asymptomatic juveniles. These results allowed us to conclude that infection by I. multifiliis is less severe in silver catfish maintained at pH 5.0-hardness 20 mg CaCO3.L-1. Increase of water hardness increases trophonts infection and impairs survival in silver catfish kept at pH 5.0, but the opposite is observed when juveniles are at pH 7.0. There was no clear evidence of a relationship between mortality and trophonts number in infected silver catfish with net ion fluxes. Infection with I. multifiliis induces liver and gill damage via lipid peroxidation products, but the same is not observed in the muscle. / O objetivo deste estudo foi determinar a intensidade da infecção pelo Ichthyophthirius multifiliis, assim como o fluxo líquido de íons (Na+, K+ e Cl-), em juvenis de jundiá expostos a diferentes pHs (5,0; 6,0; 7,0; 8,0 e 9,0 por dezesseis dias), pH (5,0 e 7,0) e dureza (20, 60 e 120 mg CaCO3/L por dezesseis dias) e os parâmetros de estresse oxidativo no fígado, brânquias e músculo nesta espécie e submetida a diferentes pHs (5,0 e 7,0 por 3 dias). O fluxo dos íons Na+, K+ e Cl- foi determinado em diferentes tempos, o número de trofontes na pele e nas brânquias foi contado e a mortalidade foi registrada diariamente. Após seis dias os peixes submetidos aos pHs 6,0; 7,0; 8,0 e 9,0-dureza de 20 mg CaCO3/L apresentaram mortalidade cumulativa (100% após oito dias) e numero de trofontes na pele e nas brânquias significativamente maior que os mantidos em pH 5,0-dureza de 20 mg CaCO3/L. Jundiás infectados apresentaram efluxo de Na+ e K+ significativamente maior no primeiro dia, havendo uma recuperação (influxo) a partir do segundo dia em relação aos juvenis assintomáticos. Juvenis de jundiá infectados com I.multifiliis e expostos aos pHs 5,0 e 7,0 apresentaram significativo aumento dos níveis de TBARS no fígado e nas brânquias em relação aos juvenis assintomáticos. A atividade da catalase no fígado dos juvenis de jundiás infectados e expostos a ambos pHs foi significativamente maior e menor (1º e 3º dia), em relação aos juvenis assintomáticos. A atividade da GST no fígado e nas brânquias aumentou durante todo o período experimental em relação aos juvenis assintomáticos. O músculo dos juvenis infectados e mantidos em pH 5,0 apresentou significativa diminuição nos níveis de TBARS no terceiro dia comparado aos juvenis assintomáticos. A atividade da catalase foi significativamente menor no músculo dos juvenis infestados e submetidos ao pH 5,0 e 7,0 em todos os dias experimentais, exceto no primeiro dia em pH 7,0 quando comparada aos juvenis assintomáticos. O músculo dos juvenis infectados apresentou atividade da GST significativamente menor em todo o período experimental em ambos pH 5,0 e 7,0 quando comparados aos juvenis assintomáticos. Estes resultados nos permitem concluir que a infecção pelo I. multifiliis é menos severa em jundiás mantidos em pH 5,0-dureza de 20 mg CaCO3/L. O aumento da dureza da água aumenta a infecção pelos trofontes e afeta a sobrevivência dos jundiás mantidos em pH 5,0, mas o oposto é observado quando os juvenis estão no pH 7,0. Não houve uma evidência clara da relação entre a mortalidade e o número de trofontes nos juvenis de jundiá infectados com o fluxo líquido de íons. A infecção por I. multifiliis induz danos no fígado e brânquias, via produtos da peroxidação lipídica, o mesmo não ficando evidenciado no músculo.

Meloidogyne incognita (Kofoid and White) is a major pest of soybean in South Africa and due to its high level of pathogenicity to the crop it is quintessential that research in this regard should receive priority. Root-knot nematode control has in the past mostly included the use of nematicides, while crop rotation and inclusion of cultivars with genetic host plant resistance (henceforth referred to as resistance only) to these pests were also used. Since no synthetically-derived and/or biological agents are registered locally as nematicides on soybean, the use of resistant cultivars represents one of the most viable and environmentally-friendly strategies to protect local soybean crops against damage resulting from parasitism by M. incognita. Although numerous exotic soybean cultivars have been identified with resistance to M. incognita, only a few locally adapted ones have proved to exhibit resistance to the latter species. Moreover, at present Egret is the only cultivar still available for commercial use in South Africa. Little and fragmented information is, however, available on the use of plant enzymes, that are interrelated in biochemical pathways that are expressed in root-knot nematode resistant cultivars, for its use as an additional parameter to exploit such a trait. Therefore, the present study was undertaken to identify M. incognita resistance in selected, locally adapted soybean cultivars by quantifying and exploiting the latter trait by using enzyme activities as an additional parameter. In addition, resistance to M. incognita in selected resistant soybean cultivars was also verified by means of histopathological studies to identify cellular changes associated with the trait. In the first part of the present study, 31 locally adapted soybean cultivars of which 23 were commercially available in the 2012 growing season were evaluated for resistance to M. incognita. The latter was done by means of traditional screening protocols for which M. incognita-gall rating, egg and second-stage juvenile as well as the reproductive factor data per root system for each cultivar screened were recorded. Two greenhouse experiments were subsequently conducted concurrently, one of which the abovementioned nematode parameters were recorded 30 and the other 56 days after inoculation. Reproduction factor values were used as the main criterium to identify M. incognita resistance in local soybean cultivars since it is considered as a more reliable parameter for this specific type of evaluations. Reproduction factor values equal to and lower than one, indicating resistance to the M. incognita population used in this study, were recorded only for cultivar LS5995, as well as seven pre-released GCI cultivars. These eight cultivars also had very low egg, as well as egg and second-stage juvenile counts per root system, all of which differed significantly from the susceptible control, as well as a number of other cultivars. Root gall indices, on the other hand, did not show consistent results in terms of the identification of the host status of the 31 cultivar screened during this study. Using reproduction factor values, local farmers can thus be supplied with information on the resistance of commercially-available soybean cultivars. Eventually, such M. incognita-resistant cultivars can be used to reduce population levels of this nematode pest in fields of producers and also as valuable germplasm sources in breeding programs to introgress/stack this trait in newly-developed soybean cultivars. The second part of the study aimed to verify and exploit M. incognita-resistance in soybean either identified as resistant or susceptible during the screenings experiments, using enzymatic activity as biochemical markers. Cultivar LS5995 was included as the resistant and Dundee as the susceptible standard. The activity of three enzymes, namely guaiacol peroxidase, lipoxygenase and catalase were recorded at different time intervals in roots and leaf samples of the latter cultivars, of both nematode-inoculated and nematode-free plants of each cultivar. Significant (P ≤ 0.05) increases in guaiacol peroxidase activity in leaf and root samples of the M. incognita-resistant cultivars GCI7 and LS5995 (inoculated with J2) were recorded 24 hours (h) after onset of the experiment. Use of this enzyme thus emanated as a useful parameter to identify soybean cultivars that exhibit resistance against M. incognita, especially in leaves, which could substantially reduce the time needed to screen cultivars. In terms of lipoxygenase activity recorded, substantial variation existed between the cultivars tested. The M. incognita-susceptible cultivar Egret was the only cultivar for which a significant (P ≤ 0.05) increase in lipoxygenase activity in the roots was evident 24 h after inoculation. However, during the 48 h sampling time, significant (P ≤ 0.05) differences in lipoxygenase activity were also recorded for the two M. incognita resistant cultivars GCI7 and LS5995. Although the increase in lipoxygenase activity for the susceptible cultivar Egret was unexpected, it may indicate that some level of resistance is present in the latter cultivar, which has in previous studies been identified as resistant to M. incognita. Other factors such as a different M. incognita populations used and temperature differences in greenhouse conditions that applied in this study compared to that for an earlier study may, however, serve as explanations for the latter differences in host status identification of cultivar Egret. In terms of catalase activity recorded in leaf samples of the M. incognita-resistant cultivar LS5995, substantial reductions of as much as 35.6 % were recorded for J2-inoculated plants compared to those of the J2-free control plants. In leaf samples of the susceptible cultivars, Egret and Dundee, catalase was also reduced, but to a lesser extent and ranged from 6 to 26 %. Conversely, catalase activity in the leaves of J2-inoculated plants of the highly susceptible cultivar LS6248R was substantially increased by as much as 29.3 %. Enzyme data obtained as a result of the current study thus generally complemented those of traditional screening assays in which resistance in locally adapted cultivars were identified to a certain degree. It is, however, recommended that enzyme activity, to be used as bio-markers, still needs further refinement and more investigation to optimise their use in identification, verification and exploitation of M. incognita resistance in soybean cultivars. The third and final part of the study encompassed a comparison of cellular changes induced by M. incognita in resistant and susceptible soybean cultivars to verify the resistant reactions expressed in the enzyme data. According to light- and transmission electron microscope observations, distinct differences in the appearance and development of giant cells in roots of the M. incognita-resistant cultivars LS5995 and GCI7 existed when compared to those in roots of the susceptible cultivars Dundee and LS6248R. In the latter cultivars, giant cells that formed were characteristically large and contained a dense cytoplasm, with thick irregularly surfaced cell walls. Cell walls also displayed thick aggregations that appeared to be cell-wall ingrowths. These giant cells are optimal to facilitate M. incognita development and reproduction. In contrast, giant cells that were associated with the resistant cultivars LS5995 and GCI7 were small, irregularly shaped and contained increased amounts of deposited cell-wall material in the cytoplasm known as cell wall inclusions. Necrosis was also present in M. incognita-infected root cells of both cultivars. Such giant cells have been associated with retarded feeding, development and reproduction of the latter root-knot nematode species. However, it was evident that neither GCI7 nor LS5995 are immune to M. incognita since J2 survived and developed to third- and fourth and ultimately mature females that reproduced in their roots. Optimal giant cells that were formed in the roots of the M. incognitasusceptible cultivars Dundee and LS6248R thus supported the nutritional needs of the developing M. incognita individuals and led to significant increases in M. incognita populations 56 days after inoculation as was evident from the high reproduction factor values that were obtained for such cultivars during host status assessments that represented the first part of this study. The opposite was recorded the M. incognita-resistant cultivars LS5995 and GCI7 since sub-optimal giant cells in their roots could not sustain high offspring from such mature females. The presence of necrotic root tissue adjacent to giant cells, furthermore, indicated that hypersensitive reactions occurred in the latter resistant cultivars. Enzyme data obtained in the second part of this study supported the presence of hypersensitive reactions in root cells of the latter resistant cultivars. Guaiacol peroxidase and lipoxygenase inductions in particular in plant tissues have been reported to play integral roles in hypersensitive reactions that are exhibited by cultivars that are resistant to pests and diseases. Finally, results obtained from the different parts of this study complemented each other. It resulted in the resistance that was identified in the GCI7 pre-released cultivar being verified and exploited against that of the resistant standard LS5995. Research that was done during this study also represented the first investigations into the use of enzymes as biochemical markers of resistance against M. incognita in soybean in South Africa. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

Meloidogyne incognita (Kofoid and White) is a major pest of soybean in South Africa and due to its high level of pathogenicity to the crop it is quintessential that research in this regard should receive priority. Root-knot nematode control has in the past mostly included the use of nematicides, while crop rotation and inclusion of cultivars with genetic host plant resistance (henceforth referred to as resistance only) to these pests were also used. Since no synthetically-derived and/or biological agents are registered locally as nematicides on soybean, the use of resistant cultivars represents one of the most viable and environmentally-friendly strategies to protect local soybean crops against damage resulting from parasitism by M. incognita. Although numerous exotic soybean cultivars have been identified with resistance to M. incognita, only a few locally adapted ones have proved to exhibit resistance to the latter species. Moreover, at present Egret is the only cultivar still available for commercial use in South Africa. Little and fragmented information is, however, available on the use of plant enzymes, that are interrelated in biochemical pathways that are expressed in root-knot nematode resistant cultivars, for its use as an additional parameter to exploit such a trait. Therefore, the present study was undertaken to identify M. incognita resistance in selected, locally adapted soybean cultivars by quantifying and exploiting the latter trait by using enzyme activities as an additional parameter. In addition, resistance to M. incognita in selected resistant soybean cultivars was also verified by means of histopathological studies to identify cellular changes associated with the trait. In the first part of the present study, 31 locally adapted soybean cultivars of which 23 were commercially available in the 2012 growing season were evaluated for resistance to M. incognita. The latter was done by means of traditional screening protocols for which M. incognita-gall rating, egg and second-stage juvenile as well as the reproductive factor data per root system for each cultivar screened were recorded. Two greenhouse experiments were subsequently conducted concurrently, one of which the abovementioned nematode parameters were recorded 30 and the other 56 days after inoculation. Reproduction factor values were used as the main criterium to identify M. incognita resistance in local soybean cultivars since it is considered as a more reliable parameter for this specific type of evaluations. Reproduction factor values equal to and lower than one, indicating resistance to the M. incognita population used in this study, were recorded only for cultivar LS5995, as well as seven pre-released GCI cultivars. These eight cultivars also had very low egg, as well as egg and second-stage juvenile counts per root system, all of which differed significantly from the susceptible control, as well as a number of other cultivars. Root gall indices, on the other hand, did not show consistent results in terms of the identification of the host status of the 31 cultivar screened during this study. Using reproduction factor values, local farmers can thus be supplied with information on the resistance of commercially-available soybean cultivars. Eventually, such M. incognita-resistant cultivars can be used to reduce population levels of this nematode pest in fields of producers and also as valuable germplasm sources in breeding programs to introgress/stack this trait in newly-developed soybean cultivars. The second part of the study aimed to verify and exploit M. incognita-resistance in soybean either identified as resistant or susceptible during the screenings experiments, using enzymatic activity as biochemical markers. Cultivar LS5995 was included as the resistant and Dundee as the susceptible standard. The activity of three enzymes, namely guaiacol peroxidase, lipoxygenase and catalase were recorded at different time intervals in roots and leaf samples of the latter cultivars, of both nematode-inoculated and nematode-free plants of each cultivar. Significant (P ≤ 0.05) increases in guaiacol peroxidase activity in leaf and root samples of the M. incognita-resistant cultivars GCI7 and LS5995 (inoculated with J2) were recorded 24 hours (h) after onset of the experiment. Use of this enzyme thus emanated as a useful parameter to identify soybean cultivars that exhibit resistance against M. incognita, especially in leaves, which could substantially reduce the time needed to screen cultivars. In terms of lipoxygenase activity recorded, substantial variation existed between the cultivars tested. The M. incognita-susceptible cultivar Egret was the only cultivar for which a significant (P ≤ 0.05) increase in lipoxygenase activity in the roots was evident 24 h after inoculation. However, during the 48 h sampling time, significant (P ≤ 0.05) differences in lipoxygenase activity were also recorded for the two M. incognita resistant cultivars GCI7 and LS5995. Although the increase in lipoxygenase activity for the susceptible cultivar Egret was unexpected, it may indicate that some level of resistance is present in the latter cultivar, which has in previous studies been identified as resistant to M. incognita. Other factors such as a different M. incognita populations used and temperature differences in greenhouse conditions that applied in this study compared to that for an earlier study may, however, serve as explanations for the latter differences in host status identification of cultivar Egret. In terms of catalase activity recorded in leaf samples of the M. incognita-resistant cultivar LS5995, substantial reductions of as much as 35.6 % were recorded for J2-inoculated plants compared to those of the J2-free control plants. In leaf samples of the susceptible cultivars, Egret and Dundee, catalase was also reduced, but to a lesser extent and ranged from 6 to 26 %. Conversely, catalase activity in the leaves of J2-inoculated plants of the highly susceptible cultivar LS6248R was substantially increased by as much as 29.3 %. Enzyme data obtained as a result of the current study thus generally complemented those of traditional screening assays in which resistance in locally adapted cultivars were identified to a certain degree. It is, however, recommended that enzyme activity, to be used as bio-markers, still needs further refinement and more investigation to optimise their use in identification, verification and exploitation of M. incognita resistance in soybean cultivars. The third and final part of the study encompassed a comparison of cellular changes induced by M. incognita in resistant and susceptible soybean cultivars to verify the resistant reactions expressed in the enzyme data. According to light- and transmission electron microscope observations, distinct differences in the appearance and development of giant cells in roots of the M. incognita-resistant cultivars LS5995 and GCI7 existed when compared to those in roots of the susceptible cultivars Dundee and LS6248R. In the latter cultivars, giant cells that formed were characteristically large and contained a dense cytoplasm, with thick irregularly surfaced cell walls. Cell walls also displayed thick aggregations that appeared to be cell-wall ingrowths. These giant cells are optimal to facilitate M. incognita development and reproduction. In contrast, giant cells that were associated with the resistant cultivars LS5995 and GCI7 were small, irregularly shaped and contained increased amounts of deposited cell-wall material in the cytoplasm known as cell wall inclusions. Necrosis was also present in M. incognita-infected root cells of both cultivars. Such giant cells have been associated with retarded feeding, development and reproduction of the latter root-knot nematode species. However, it was evident that neither GCI7 nor LS5995 are immune to M. incognita since J2 survived and developed to third- and fourth and ultimately mature females that reproduced in their roots. Optimal giant cells that were formed in the roots of the M. incognitasusceptible cultivars Dundee and LS6248R thus supported the nutritional needs of the developing M. incognita individuals and led to significant increases in M. incognita populations 56 days after inoculation as was evident from the high reproduction factor values that were obtained for such cultivars during host status assessments that represented the first part of this study. The opposite was recorded the M. incognita-resistant cultivars LS5995 and GCI7 since sub-optimal giant cells in their roots could not sustain high offspring from such mature females. The presence of necrotic root tissue adjacent to giant cells, furthermore, indicated that hypersensitive reactions occurred in the latter resistant cultivars. Enzyme data obtained in the second part of this study supported the presence of hypersensitive reactions in root cells of the latter resistant cultivars. Guaiacol peroxidase and lipoxygenase inductions in particular in plant tissues have been reported to play integral roles in hypersensitive reactions that are exhibited by cultivars that are resistant to pests and diseases. Finally, results obtained from the different parts of this study complemented each other. It resulted in the resistance that was identified in the GCI7 pre-released cultivar being verified and exploited against that of the resistant standard LS5995. Research that was done during this study also represented the first investigations into the use of enzymes as biochemical markers of resistance against M. incognita in soybean in South Africa. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

No description available.

<p>Diss. (sammanfattning) Umeå : Umeå universitet, 1983, härtill 5 uppsatser</p> / digitalisering@umu

Submitted by Cristiane Chim (cristiane.chim@ucpel.edu.br) on 2016-09-13T16:35:46Z No. of bitstreams: 1 carolina - Copia.pdf: 1129007 bytes, checksum: deaef0e96e4837a47c36de1f6dc1e109 (MD5) / Made available in DSpace on 2016-09-13T16:35:46Z (GMT). No. of bitstreams: 1 carolina - Copia.pdf: 1129007 bytes, checksum: deaef0e96e4837a47c36de1f6dc1e109 (MD5) Previous issue date: 2010-11-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES# / #2075167498588264571# / #600 / Objectives: The aim of this study was evaluate uric acid level in a population–based sample of young adults (18 to 24 years old). People with bipolar and depression disorder were compared with healthy psychiatric subjects without a history of mood episodes. Methods: Case-control study nested in a population-based sample. The diagnosis was confirmed with the Structured Clinical Interview for DSM-IV. The uric acid was assessed by commercial kits Results: The sample consisted of 216 subjects, 49 with diagnosis for bipolar disorder, 76 with depression and 91 population control. The uric acid levels were similar (control = 4.08 ± 1.27 mg/dL, depression = 3.78 ± 1.00 mg/dL e bipolar disorder =3.86 ± 1.33 mg/dL, p= 0,251). For maniac/hippomaniac and depressive episodes, were observed a tendency to increase in acid uric levels in maniac/hippomaniac episodes (4.43 ± 1.74 mg/dL) and a decrease in depressive episodes (3.70 ± 0.99 mg/dL) when compared to control subjects (4.08 ± 1.27 mg/dL)(p= 0.106). Conclusion: Uric acid levels is not correlated with diagnosis group, but the uric acid level have a tendency to presented increased in manic and/ or mixed episodes and decreased in depression episode, these result observed that levels of uric acid in mood disorders are altered according to the manifestation of symptoms. / Objetivo: O objetivo deste estudo é avaliar o nível de acido úrico em pacientes com transtornos de humor oriundo de uma amostra de base populacional com jovens adultos (18 a 24 anos), para este fim jovens com transtorno de humor bipolar e depressão foram comparados com jovens sem histórico de transtorno de humor. Métodos: Trata-se de um estudo de caso-controle aninhado a um estudo de base populacional, o diagnostico foi realizado através da Entrevista Clínica Estruturada para o DSM-IV (SCID) e os níveis de acido úrico séricos foram dosados utilizando-se kits comerciais. Resultados: A amostra foi constituída de 216 jovens, 49 com diagnostico de transtorno bipolar, 76 com depressão e 91 controles sem historia psiquiátrica prévia, os níveis de acido úrico entre os três grupos foram similares (controle = 4.08 ± 1.27 mg/dL, depressão = 3.78 ± 1.00 mg/dL e transtorno bipolar =3.86 ± 1.33 mg/dL, p= 0,251). Quando avaliados os níveis de ácido úrico entre os episódios mania/hipomania e depressivo, observa-se uma tendência no aumento do ácido úrico no episódio maníaco/misto (4,43 ± 1,74 mg/dL) e uma diminuição no episódio depressivo (3,70 ± 0,99 mg/dL) quando comparados aos jovens do grupo controle (4,08 ± 1,27 mg/dL)(p= 0,106). Conclusão: Os níveis de ácido úrico não foram significativos entre os grupos diagnósticos, porém os níveis de acido úrico apresentaram uma tendência para o aumento nos episódios maníacos e/ou mistos e uma diminuição no episódio depressivo, com estes resultados podemos observar que os níveis de acido úrico nos transtornos de humor podem estar alterados de acordo com a manifestação dos sintomas

The photosynthetic water splitting reaction performed in green plants, algae and cyanobacteria is perhaps one of the most important reactions on the planet. The reaction is catalysed by a tetranuclear manganese cluster that is driven by sunlight and as such has received a high degree of interest in the context of solar fuels research. Due to the intricacy of the bioinorganic systems, the molecular mechanisms of the reactions are unknown and structural elucidation of the active sites is complicated. Computational techniques can provide considerable support in the analysis and interpretation of the complex EPR spectra of such biological systems. In this work, the molecular and electronic structures of several multinuclear manganese containing bioinorganic systems are investigated using BS-DFT. A particular focus of this work is the provision of high quality calculated EPR parameters yielding structural and mechanistic insight. In the first results chapter, the MnIIIMnIV superoxidised state of manganese catalase as well as azide inhibited manganese catalase is studied. Several variants are proposed and analysed on the basis of their calculated EPR parameters. The results presented in this chapter offer a new interpretation of previous experimental assignments. Chapter 6 features investigations on the S2 state of the Oxygen Evolving Complex of Photosystem II. In this chapter both the native OEC as well as the strontium substituted OEC are studied, in order to investigate how replacement of the calcium ion affects the structure of the OEC. The final results chapter presents calculations on the split signal S2Yz dot radical formed on the transition from the S2 to S3 state, as well as studying the S3 state. The calculation of various EPR hyperfine couplings and their comparison with available experimental data has provided key insights into the electronic structure of the OEC.

Submitted by Irvana Coutinho (irvana@ufpa.br) on 2011-12-01T13:58:17Z No. of bitstreams: 1 Tese_MariaAuxMenezes.pdf: 1876253 bytes, checksum: 13fd2c4d6a3e216fdbb878a02b840f29 (MD5) / Made available in DSpace on 2011-12-01T13:58:17Z (GMT). No. of bitstreams: 1 Tese_MariaAuxMenezes.pdf: 1876253 bytes, checksum: 13fd2c4d6a3e216fdbb878a02b840f29 (MD5) Previous issue date: 2010 / A desnutrição, altamente prevalente em países em desenvolvimento, é um mau antigo que aflige a humanidade. Apresenta-se como um estado de deficiência alimentar, com déficit global de proteínas e calorias, provocando menor aporte de nutrientes às células. Alguns estudos têm mostrado evidências de interação entre desnutrição e estresse oxidativo, ocasionado pelo acúmulo de espécies reativas de oxigênio que causam danos à estrutura das biomoléculas em decorrência da desregulação entre a produção de oxidante e a depleção das defesas antioxidantes. Nesse estudo foi avaliada a utilização da farinha instantânea de amaranto adicionada de arroz na proporção de 30/70% como suplemento alimentar da dieta de base do paraense usada como modelo de indução da desnutrição experimental em ratos sobre o estresse oxidativo dos animais desnutridos comparados aos controles e aos tratados com a dieta suplementada. A dieta modelo de desnutrição (DBR-PA) foi confeccionada respeitando-se as quantidades dos alimentos consumidos rotineiramente pela população do Pará, segundo inquérito alimentar realizado na década de 70 por pesquisadores da Universidade Federal do Pará, enquanto que, a dieta utilizada como tratamento foi elaborada adicionando-se a DBRPA 30% da farinha de amaranto. As análises da composição centesimal e o perfil de aminoácidos foram realizados de acordo com as normas do Instituto Adolfo Lutz (1995) e por espectrofotometria atômica. A dieta controle foi utilizada na forma que é comercializada. Para realização do estudo utilizou-se animais no pós parto imediato de mães alimentadas na gestação com dieta controle para ratos (22% de proteínas), com peso mínimo de 6 g ao nascer. No pós parto imediato as ratas mães foram divididas em 3 grupos a saber: grupo controle (22% de proteínas); grupo desnutridos (DBR-PA contendo 7,8% de proteínas) grupo 3 tratados (DBR-PA+AA) suplementada com a farinha instantânea de amaranto contendo 11,33%). No pós desmame os animais foram separados e em gaiolas individuais receberam a dieta materna específica de cada grupo até os 60 dias de vida, quando foram sacrificados e realizada a coleta de sangue para as dosagens bioquímicas (colesterol total e frações, valores hemogramas (hematimetria, leucograma e plaquetas), níveis de peroxidação lipídica e atividade da catalase. Após a coleta do sangue os animais foram submetidos à exerese do fígado para posterior análise histopatológica. Os resultados revelaram que a dieta indutora da desnutrição é um modelo de desnutrição grave comum na região norte, é hipoproteica, normocalórica, com aminoácido limitante (metionina), promoveu perda de peso nos animais desde o período de aleitamento com acentuado perda de peso nas ratas mãe e nos filhotes aos desmame (21 dias), aos 28 e 60 dias de vida (p <0,05) quando comparados aos animais tratados com amaranto e aos controles. A dieta suplementada com a farinha extrusada de amaranto promoveu ganho de peso no período do aleitamento tanto nas ratas mães (p<0,05) como nos filhotes a partir do 14º dias de uso da mesma ( p<0,05), aos 21 dias (desmame)(p<0,05) aos 28 ( p< 0,05)e 60º dias de vida (p<0,05). Os animais desnutridos consumiram mais dieta em todos os momentos avaliados quando comparados aos tratados e controles (p<0,05). Não foi observada diferença entre os grupos nos valores bioquímicos de hematimetria, leucograma, plaquetas, colesterol total e frações. Os níveis de peroxidação lipídica não apresentaram diferença estatística entre os grupos. A atividade da catalase foi maior no grupo tratado com a suplementação da farinha de amaranto quando comparado aos desnutridos.Os animais tanto os tratados com amaranto como os desnutridos apresentaram esteatose hepática e processo inflamatório dos hepatócitos.O estudo mostrou que a desnutrição imposta não ocasionou estresse oxidativo, porém a diminuição da atividade da catalase nos animais desnutridos pode ter sido ocasionado pela diminuição da síntese da catalase. / Malnutrition was highly prevalent in developing countries, is an ancient evil that afflicts humanity, presents itself as a state of nutritional deficiency, with an overall deficit of calories and proteins, causing a lower supply of nutrients to cells. Some studies have shown evidence of interaction between malnutrition and oxidative stress caused by accumulation of reactive oxygen species that cause damage to the structure of biomolecules due to the deregulation of the production of oxidants and depletion of antioxidant defenses. In this study we evaluated the use of instant amaranth flour added rice at a ratio of 30/70% as a food supplement in the diet base used as a model of Para Induction of malnutrition in rats on oxidative stress in malnourished animals compared to controls and treated with supplemented diet. The model of malnutrition diet (RBDPA) was made respecting the quantities of food consumed routinely by the population of Pará, the second dietary survey carried out in the 70's by researchers at the Federal University of Pará, whereas the diet used as a treatment was prepared by adding the DBR-PA 30% of amaranth flour. The results of proximate composition and amino acid were performed in accordance with the standards of the Institute Adolfo Lutz (1995) and by atomic spectrophotometry. The control diet was used as it is available. For the study animals in the immediate postpartum mothers fed with control diet during pregnancy to rats (22% protein) with a minimum weight of 6 g at birth in the immediate postpartum mother rats were divided into three groups: Group control (22% protein); malnourished group (RBD-PA containing 7.8% protein) 3 treated group (RBD-PA + AA) supplemented with amaranth flour instant containing 11.33%). In the post weaning the animals were separated into individual cages and received specific maternal diet of each group until 60 days old when he was done and sacrificed to collect blood for biochemical testing (total cholesterol and fractions, values, blood counts (red blood cells, WBC and platelet counts), levels of lipid peroxidation and catalase activity. After blood collection the animals underwent liver resection for posterior histopathological analysis. The results revealed that the diet induces malnutrition is a model of severe malnutrition in the region eat north, is hipoproteic, normocaloric with limiting amino acid (methionine), has promoted weight loss in animals from the period of lactation with marked weight loss in rats and mother in the weaning pups (21 days), 28 and 60 days old (p <0.05) compared to animals treated with amaranth and controls. The diet supplemented with amaranth flour extruded promoted weight gain during the period of breastfeeding mothers in both rats (p <0.05) in the puppies as apartir the 14th day of using the same (p <0.05) at 21 days (weaning) (p <0.05) to 28 (p <0.05) and 60th days of life (p <0.05). Malnourished animals consumed more diet at all times evaluated and treated when compared to controls (p <0.05). There was no difference between groups in biochemical values of red blood cells, WBC, platelets, total cholesterol and fractions. levels lipid peroxidation did not differ between groups. Catalase activity was higher in the group treated with supplementation of amaranth flour when compared to both desnutridos.Os animals treated with amaranth as the undernourished have hepatic steatosis and inflammation in hepatocytes. The study revealed that malnutrition imposed did not cause oxidative stress, however, the decrease of catalase activity in malnourished animals may have been caused by decreased synthesis of catalase.

A atividade de catalase em Candida albicans tem sido sugerida como um mecanismo de resistência ao antifúngico anfotericina B. Neste contexto, poucos são os estudos de enzimas como catalase e superóxido dismutase em leveduras do gênero Candida expostas a diferentes situações. Assim, este estudo teve por objetivo investigar o efeito da exposição de Candida a antineoplásicos, íons metálicos e antifúngicos como fluconazol e anfotericina B sobre a atividade dessas enzimas. Os resultados apontaram que o antineoplásico metotrexato aumentou a atividade da catalase em C. albicans, que íons metálicos como cobre, zinco, manganês e ferro produzem um efeito variável na atividade de superóxido dismutase, bem como, um efeito variável de um íon no acúmulo de outro. Também verificamos através de nossos resultados que a indução de resistência ao fluconazol e anfotericina B aumentam a atividade de catalase e superóxido dismutase em C. albicans e C. dubliniensis. Esses resultados sugerem que o antineoplásico metotrexato e a indução de resistência a anfotericina B e fluconazol podem gerar um estresse oxidativo em leveduras do gênero Candida que possivelmente se adaptam a esse estresse aumentando seus mecanismos de defesa antioxidante. Esse efeito pode induzir a uma maior resistência desses organismos ao ataque de células fagocíticas do hospedeiro. / Catalase is an enzyme that has been suggested to be involved in resistance mechanisms to antifungal drug such as amphotericin B. There are few studies focusing on catalase and superoxide dismutase in yeasts, such as Candida, exposed to different situations. Thereby, the aim of the present study was to investigate the effect of exposing Candida to antineoplastic drugs, metallic ions and antifungial drugs, namely fluconazole and amphotericin B, on catalase and superoxide dismutase activities. Results show that methotrexate induced catalase activity in C. albicans and that metallic ions, such as copper, zinc, manganese and iron produced a variable effect on superoxide dismutase activity of C. albicans, as well as a variable effect in the uptake of one ion on another. We also showed that fluconazole and amphotericin B resistance increased catalase and superoxide dismutase activity in C. albicans and C. dubliniensis. These results suggest that methotrexate as well as the induction of fluconazole- and amphotericin B-resistance may induce oxidative stress in yeasts such as Candida, which may adapt by increasing antioxidant defense mechanisms. This effect may induce a major resistance of this yeast to phagocytic cell attack.

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