This study has investigated the involvement of photosynthetic electron transport chain on the regulation of gene expression of methionine sulfoxide reductase (UfMSR) in the marine macroalga Ulva fasciata Delile.UfMSRA is from copper stress and UfMSRB ir from hypersalinity stress. UfMSRA is similar to Arabidopsis AtMSRA4 and UfMSRB is similar to AtMSRB1. UfMSRA is specific to the MetSO S-enantiomer and UfMSRB catalytically reduces the MetSO R-enantiomer. Both enzymes are required, since in the cell oxidation of Met residues at the sulfur atom results in a racemic mixture of the two stereoisomers. UfMSRA and UfMSRB transcripts were increased by white light, blue light and red light with the maximum at 1 h following a decline, but kept constant in the dark. The magnitude of UfMSRA and UfMSRB transcript increase showed a positive linear correlation to increasing light intensity from 0-1200 u mole¡Pm-2¡Ps-1. The treatment with linear electron transport chain inhibitors, hydroxylamine, 3-(3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) and stigmatellin, effectively inhibited PS II activity under 300 u mole¡Pm-2¡Ps-1 irradiance. DBMIB and stigmatellin can increase UfMSRA transcript that was reversed by 2,6-dichlorophenolindophenol (DCPIP), a PS I electron donor. It indicates that the block of electron transport of the downstream of cytochrome b6f indeuces UfMSRA gene expression. Hydroxylamine, DCMU and DBMIB decreased UfMSRB transcript that was not reversed by DCPIP while stigmatellin increased UfMSRB mRNA level, reflecting a role of reduced state with Qo site located at cytochrome b6f on the induction of UfMSRB gene expression. The cyclic electron transport chain inhibitors, antimycin A that inhibited photosynthetic electron transport, can inhibit the increase of UfMSRA and UfMSRB transcripts by irradiance. UfMSRA and UfMSRB gene expression were both modulated by cyclic electron transport chain and linear electron transport chain. These results reveal that photosynthetic electron transport chain modulates UfMSRA and UfMSRB gene expression by change its redox state.

Made available in DSpace on 2014-06-11T19:27:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-29Bitstream added on 2014-06-13T18:31:32Z : No. of bitstreams: 1 furlan_b_me_rcla.pdf: 3556255 bytes, checksum: b8dadd1a50eb8caa4d6eb51e31dc8f1e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O gênero Burkholderia compreende um grupo de bactérias muito diversificado, ocupando vários nichos ecológicos e possui espécies que causam doenças, mas outras espécies apresentam habilidades importantes para os ramos da agricultura, biotecnologia e do ambiente, como a biodegradação. Essas bactérias são morfologicamente semelhantes e o gênero está dividido em dezessete genomovars, onde espécies semelhantes geneticamente são agrupadas, formando o Complexo Burkholderia cepacia (CBC). Por meio de estudos moleculares do gene 16S rRNA e do gene recA foi possível fazer a classificação adequada em espécies dos 450 isolados obtidos da Terra Preta Antropogênica (TPA) e adjacentes, em quatro sítios (TPA Caldeirão Cultivado; TPA Caldeirão Capoeira; TPA Hatahara e TPA Mina-I), foram obtidos 177 isolados do gênero Burkholderia. Desses isolados, pela análise do gene 16S rRNA foi possível classificar 157 isolados ao nível de espécie e pela análise do gene recA somente 105 isolados foram classificados neste mesmo nível. Esses isolados foram utilizados no teste de biodegradação dos hidrocarbonetos. Os hidrocarbonetos poliaromáticos (HPAs) são compostos orgânicos resultantes da combustão incompleta da matéria orgânica e dos derivados de petróleo, são pouco solúveis em água e muito tóxicos para as células, por isso, não são metabolizados por muitos micro-organismos e acabam contaminando e inviabilizando os ambientes. Nos testes de biodegradação os substratos utilizados foram o naftaleno, o fenantreno e o diesel, juntamente com o indicador redox 2,6- diclorofenol-indofenol (DCPIP), que sofre descoloração (de azul para incolor) quando as células utilizam os substratos como fonte de carbono para o crescimento celular, gerando elétrons que vão reduzir o indicador. Pela análise do teste, 19 isolados degradaram o naftaleno, 16 degradaram... / The genus Burkholderia comprises a very diverse group of bacteria occupying various ecological niches and has species that cause disease, but other species have important skills to the branches of agriculture, biotechnology and the environment, as biodegradation. These bacteria are morphologically similar genus and is divided into seventeen genomovars, where genetically similar species are grouped together, forming the Burkholderia cepacia complex (BCC). Through molecular studies of 16S rRNA and recA gene was possible to make the appropriate classification of species in 450 isolates of Terra Preta Antropogênica (TPA) and adjacent at four sites (TPA Caldeirão Cultivado; TPA Caldeirão Capoeira; TPA Hatahara e TPA Mina-I) were obtained 177 isolates of the genus Burkholderia. These isolates by 16S rRNA gene analysis was possible to classify 157 isolates to species level and the recA gene analysis only 105 isolates were classified in the same level. These isolates were used to test the biodegradation of hydrocarbons. Polyaromatic hydrocarbons (PAHs) are organic compounds resulting from incomplete combustion of organic matter and petroleum derivatives, are not very soluble in water and very toxic to cells, therefore, are not metabolized by many microorganisms to contaminate and render environments. In biodegradation tests the substrates used were naphthalene, phenanthrene and the diesel, along with the redox indicator 2,6- dichlorophenol-indophenol (DCPIP), who suffers discoloration (blue to colorless) when cells use the substrates as a source of carbon for cell growth, generating electrons that will reduce the indicator. By analysis of the test, 19 isolates degraded naphthalene, phenanthrene degraded the 16 and 126 degraded diesel, generating a total of 132 isolates of the genus Burkholderia that have the ability to degrade at least... (Complete abstract click eletronic access below)