Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Akademisk avhandling--Copenhagen. / Bibliography: p. 102-109.

Akademisk avhandling--Copenhagen. / Bibliography: p. 102-109.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniversit, 2008. / Härtill 5 uppsatser.

Made available in DSpace on 2014-06-11T19:26:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-18Bitstream added on 2014-06-13T19:13:01Z : No. of bitstreams: 1 amaral_al_me_jabo.pdf: 755163 bytes, checksum: 38fef006637923d725907da11533302e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Estudos laboratoriais foram realizados com o objetivo de estudar a caracterização genética de plantas de Euphorbia heterophylla, provenientes de áreas em que a resistência aos herbicidas inibidores da ALS (Acetolactase) estava caracterizada (Santo Ângelo, RS), em processo de desenvolvimento (Sonora, MS) e onde nunca havia sido aplicado herbicida com este mecanismo de ação (Jaboticabal, SP). Testes preliminares comprovaram elevada resistência para as plantas provenientes de Santo Ângelo, moderada resistência para plantas de Sonora e elevada susceptibilidade para plantas provenientes de Jaboticabal. A análise dos resultados através das isoenzimas revelou que existem pequenas diferenças entre as três populações estudadas. A análise do DNA dos indivíduos das diferentes populações através de marcadores moleculares RAPD, permitiu a construção do Dendrograma de Cluster, que mostra uma similaridade mínima de 88% e máxima de 99% entre os diferentes indivíduos, quer pertencentes à mesma população, quer pertencentes às diferentes populações. Tal análise permitiu inferir que, apesar dos indivíduos analisados mostrarem grande similaridade entre si, apresentam variabilidade genética entre os indivíduos e as populações estudadas, de acordo com a conclusão obtida quando da utilização das isoenzimas. Crescendo em condições similares, o biótipo da Santo Ângelo apresentou maior absorção de fósforo em comparação com os demais, e maior absorção de potássio em relação ao biótipo de Jaboticabal. Comparando a densidade estomática, houve diferença estatística entre os três biótipos, sendo maior para o biótipo mais tolerante ao herbicida e menor para o susceptível. Não foi possível estabelecer qualquer relação confiável entre as características morfológicas e de crescimento das plantas e a resistência ao imazethapyr. / Laboratory studies were carried out aim to characterize genetically Euphorbia heterophylla plants were collect in three regions. At Santo Ângelo (RS) region this plant is highly resistant to ALS inhibitors herbicides, but moderately at Sonora (MS) and susceptible at Jaboticabal region. Greenhouse tests confirmed the plants reaction in face of imazethapyr spraying. The isoenzymes studies showed small differences between the three populations. The DNA analysis using molecular markers make feasible the Cluster dendrogram showing 88-99% of similarity comparing plants, regardless the plant origin. Besides the high similarity index between the plants, it was possible to determine lower genetic variation in Jaboticabal and Santo Ângelo populations using isoenzymes technique. The nitrogen and potassium contents in the plants shoot was higher in the Santo Ângelo byotipe, although there was no difference between the K contents when the Jaboticabal and Sonora byotipes were compared. The stomata and trichomes densities decreased in the same order of the plant tolerance to herbicide: Santo Ângelo > Sonora > Jaboticabal. None correlation between biotype resistance to imazethapyr and the plant morphology features for the three biotypes studied. The differences in the plant feature may be attributable to the adaptative mechanism of the plant to the regional characteristics they were collected.

Orientador: Vera Nisaka Solferini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T11:25:29Z (GMT). No. of bitstreams: 1 Bertagna_Maina_M.pdf: 3610709 bytes, checksum: 15a2936742bc15364c08a56eed4dbbeb (MD5) Previous issue date: 2007 / Resumo: A fragmentação do habitat é o processo pelo qual uma área contínua pode ser tanto reduzida quanto dividida em áreas menores, chamadas de fragmentos. Conforme as paisagens florestais tornam-se fragmentadas, as populações são reduzidas, diminuindo a diversidade de espécies. A perda de espécies pode ser devido à redução da área, à perda de heterogeneidade ambiental e à perda de variabilidade genética. Em plantas, as conseqüências genéticas da fragmentação do habitat são mais complexas devido a características da história de vida de cada espécie. Em espécies arbóreas pioneiras, a extinção e a recolonização podem aumentar o fluxo gênico e reduzir a diferenciação entre as populações. Assim, estudos de genética de populações de ambientes fragmentados permitiriam entender quais são os mecanismos que envolvem desde a dinâmica destas populações nestes ambientes e o fluxo gênico entre elas. Através da eletroforese de isozimas, Croton floribundus (Euphorbiaceae) foi estudada em seis remanescentes de Mata Atlântica, pertencentes à Área de Proteção Ambiental de Souzas e Joaquim Egídio, Campinas, SP. Os objetivos deste trabalho foram investigar e comparar a variabilidade genética entre e dentro de fragmentos, de adultos e jovens de C. floribundus, fazendo inferências sobre o fluxo gênico e sua importância em uma paisagem fragmentada. Amostras de adultos e jovens foram coletadas e analisadas através das estimativas de variabilidade genética intrapopulacional e dos níveis de estruturação populacional a partir das estatísticas-F de Wright (parâmetro q). Os altos índices de diversidade genética e pouca diferenciação genética entre as amostras estudadas indicam que C. floribundus consiguiu manter a variabilidade genética de suas populações em curto prazo, sob condições de paisagem antropizada. Foi observada uma alta variabilidade genética e um alto índice de endocruzamento que podem ser explicados pelas características da história de vida de C. floribundus. A fragmentação recente, o número limitado de gerações transcorridas após a fragmentação, a dominância na paisagem, a alta densidade de indivíduos e à ocorrência de fluxo gênico entre fragmentos mais próximos podem ter facilitado a manutenção da variabilidade genética e a baixa diferenciação entre as amostras de adultos e jovens de C. floribundus estudadas / Abstract: Habitat fragmentation is the process during which a large and continuous area is reduced or divided in small patches, called remnants. As forest landscapes are fragmented, their populations are reduced, so the species diversity. The loss of species may be due to the reduction of the area, of the environmental heterogeneity and of the genetic variability. In plants, the genetic consequences of habitat fragmentation are complex due to the particularities of the of each species¿ life history. In pioneer species, recurrent events of extinction and recolonization can promote gene flow and reduce the differentiation between populations. Thus, genetic studies of fragmented populations may help to understand the mechanisms involved in the dynamics of these populations as well as the levels of gene flow among them. Through electrophoretic procedures, Croton floribundus (Euphorbiaceae) was studied in six remnants of Atlantic Forest, belonging to the Área de Proteção Ambiental de Souzas e Joaquim Egídio, Campinas, SP. The objectives of this study were to investigate and compare the genetic variability within and among samples of adults and juveniles of C. floribundus, making inferences about the levels of gene flow and its importance in a fragmented landscape. Samples were collected and analyzed through estimates of intrapopulacional genetic variability and levels of population estrutucture. The high populational genetic diversity and the low genetic differentiation between the studied samples indicate that populations of C. floribundus keep their genetic variability in a short term, under the conditions of a disturbed landscape. The high genetic variability and the high levels of inbreeding can be explained by the life history characteristics of C. floribundus. The recent fragmentation, with a limited number of generations, the abundance of this species in the landscape, the high density of individuals and the occurrence of gene flow between close remnants may mantain of the high genetic variability and the low differentiation among the studied samples of adults and juveniles of C. floribundus / Mestrado / Genetica Animal e Evolução / Mestre em Genética e Biologia Molecular

Abstract Collagen prolyl 4-hydroxylases (C-P4Hs) and related enzymes catalyze the hydroxylation of certain proline residues in animal collagens and plant hydroxyproline-rich proteins, respectively. Animal C-P4Hs and their isoenzymes have been characterized to date from humans, rodents, insects and nematodes. Most of the animal C-P4Hs are α2β2 tetramers in which protein disulphide isomerase (PDI) serves as the β subunit, but the nematode C-P4Hs characterized so far have unique molecular compositions. Two P4Hs have been cloned from the plant Arabidopsis thaliana and one from the Paramecium bursaria Chlorella virus-1, these being monomeric enzymes. This thesis reports on the identification of a large P4H family in the green alga Chlamydomonas reinhardtii and the cloning and characterization of one member, Cr-P4H-1. This is a soluble monomer that hydroxylates in vitro several peptides representing sequences found in C. reinhardtii cell wall proteins. Lack of its activity led to a defective cell wall structure, indicating that Cr-P4H-1 is essential for proper cell wall assembly and that the other P4Hs cannot compensate for the lack of its activity. Two C. elegans genes, Y43F8B.4 and C14E2.4, predicted to code for C-P4H α subunit-like polypeptides were analyzed. Three transcripts were generated from Y43F8B.4, one of them coding for a functional C-P4H α subunit named PHY-4.1. C14E2.4 turned out not to be a C-P4H α subunit gene, as a frame-shift led to the omission of codons for two catalytically critical residues. PHY-4.1 formed active tetramers and dimers with PDI-2 and had unique substrate requirements in that it hydroxylated certain other proline-rich sequences besides collagen-like peptides. Inactivation of the Y43F8B.4 gene led to no obvious morphological abnormalities. Spatial expression of the phy-4.1 transcript and PHY-4.1 polypeptide was localized to the pharynx and the excretory duct. Taken together, these data indicate that PHY-4.1 is not involved in the hydroxylation of cuticular collagens but is likely to have other substrates in vivo. Cloning and characterization of the PHY-1 and PHY-2 subunits from the closely related nematode Caenorhabditis briggsae revealed distinct differences in assembly properties between the C. elegans and C. briggsae PHY-2 subunits in spite of their high amino acid sequence identity. Genetic disruption of C. briggsae phy-1 resulted in a less severe phenotype than that observed in C. elegans, evidently on account of its more efficient assembly of the C. briggsae PHY-2 to an active C-P4H explaining the milder phenotype. Rescue of C. elegans and C. briggsae phy-1 mutants was achieved by injection of a wild-type phy-1 gene from either species.

Abstract Lysyl hydroxylase (EC 1.14.11.4, procollagen-lysine, 2-oxyglutarate, 5-dioxygenase, Plod) catalyzes the hydroxylation of certain lysine residues in collagens and in other proteins with collagenous domains. Three lysyl hydroxylase isoforms have been cloned from human and rat. The importance of lysyl hydroxylase 1 in collagen biosynthesis is demonstrated by the heritable disorder, Ehlers-Danlos syndrome type VI, which is characterized by joint laxity, progressive scoliosis, muscle hypotonia, scleral fragility and rupture of the ocular globe. An alternatively spliced form of lysyl hydroxylase 2 seems to function as a telopeptide lysyl hydroxylase. Lysyl hydroxylase 3 has three enzyme activities, lysyl hydroxylase, hydroxylysyl galactosyltransferase (EC 2.4.1.50), and galactosylhydroxylysyl glucosyltransferase (EC 2.4.1.66) activities that have been demonstrated earlier with in vitro experiments. In this thesis study, the cDNAs of mouse lysyl hydroxylase isoforms 1, 2 and 3 were cloned and characterized and the gene structures of lysyl hydroxylase 2, Plod2, and lysyl hydroxylase 3, Plod3, were determined. Mouse lysyl hydroxylase isoforms were found to be highly homologous to the corresponding human isoforms and they were approximately 60% identical with each other. The mouse Plod3 gene has 19 exons as do the human PLOD1 and PLOD3 genes, and mouse Plod2, like the human PLOD2, has 20 exons including one alternatively spliced extra exon. The mouse isoforms were also found to have distinct tissue distributions. Phylogenetic analysis revealed that the lysyl hydroxylase genes have evolved from an ancestral gene through two gene duplication events. Lysyl hydroxylase 3 was demonstrated to be the oldest isoform, which is further supported by the association of glycosyltransferase activities with lysyl hydroxylase 3 and with the only lysyl hydroxylase of Caenorhabditis elegans. The roles of the different enzyme activities of lysyl hydroxylase 3 were determined in vivo by generating three genetically modified lysyl hydroxylase 3 mouse lines. The analysis of these mouse lines demonstrated that lysyl hydroxylase 3 possesses at least lysyl hydroxylase and glucosyltransferase activities in vivo and it functions as the main, if not the only glucosyltransferase during embryogenesis. The absence of lysyl hydroxylase 3 and, especially, its glucosyltransferase activity results in the abnormal glycosylation of type IV collagen, and thus causes a severe basement membrane defect leading to death during early development. By contrast, lysyl hydroxylase activity had no effect on embryonic development, but caused changes in the structure of the epidermal basement membrane and changes in collagen fibril organization and probably in their interactions.

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / The objective of this study was to evaluate the physiology and biochemistry of lettuce seed through germination and expression of the enzymes alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), catalase (CAT), Esterase (EST), pyruvate decarboxylase (PDC) and glutamate oxalacetate transferase (GOT) at different temperatures. Seeds of four lettuce cultivares were submitted to germination and the first germination was tested under the temperatures of 20, 25, 30, 35, 40 and 42°C. The germination speed index (IVG), the percentage of germination were estimated, and the expression of the enzyme alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), catalase (CAT), esterase (EST), pyruvate decarboxylase (PDC) and glutamate oxalacetate transferase (GOT) evaluated. The experimental design was completely randomized, in a 4x6 factorial scheme, with four cultivars and six different temperatures, with four replications. The highest values of germination and vigor were observed for cv. Everglades at 35ºC, proving the thermotolerance. The catalase may be considered a marker for identification of thermotolerant lettuce cultivars. Cultivar Everglades has potential for use in lettuce breeding programs aiming at temperature tolerance during germination. / O objetivo neste trabalho foi avaliar a fisiologia e bioquímica de sementes de alface por meio da germinação e expressão das enzimas álcool desidrogenase (ADH), malato desidrogenase (MDH), catalase (CAT), esterase (EST), piruvato descarboxilase (PDC) e glutamato oxalacetato transferase (GOT) em diferentes temperaturas. Sementes de quatro cultivares de alface foram submetidas aos testes de germinação e primeira contagem nas temperaturas de 20, 25, 30, 35, 40 e 42ºC. Foram calculados o índice de velocidade de germinação (IVG), a porcentagem de germinação, e avaliadas a expressão das enzimas álcool desidrogenase (ADH), malato desidrogenase (MDH), catalase (CAT), esterase (EST), piruvato descarboxilase (PDC) e glutamato oxalacetato transferase (GOT). Utilizou-se o delineamento experimental inteiramente casualizado, em arranjo fatorial 4x6, testando quatro cultivares e seis temperaturas, com quatro repetições. Os maiores valores de germinação e vigor foram observados para a cv. Everglades, à temperatura de 35ºC, comprovando a termotolerância. A enzima catalase pode ser considerada marcadora para identificação de cultivares de alface termotolerantes. A cultivar Everglades tem potencial para utilização em programas de melhoramento de alface com vistas à tolerância a altas temperaturas durante a germinação.