<p>The purpose with this dissertation is to study the Intersex phenomenon in South Africa, meaning the interplay between the dual sex and gender norms in society. Hence, the treatment by some medical institutions and the view of some non-medical institutions upon this ‘treatment’, have been studied in relation to the Intersex infant’s human rights and citizenship rights. The thesis has moreover also investigated how young Intersex children are included/excluded and mentioned/not mentioned within South Africa’s legal system and within UN’s Convention on the Rights of the Child.</p><p>Furthermore, because Intersex children are viewed as ‘different’ on two accounts – their status as infants and born with an atypical congenital physical sexual differentiation, the thesis’ theoretical framework looks at the phenomenon from three perspectives – ‘the politics of difference’, human rights, and citizenship rights directed towards infants. The theoretical frameworks have been used to ask questions in relation to the empirical data, i.e. look at how the Intersex infants are ‘treated’ in relation to their status as ‘different’; and also in relation to the concept of being recognized, respected and allowed to partake in deciding whether to impose surgery or not. Moreover, what ‘treatment’ serves the best interest of the Intersex child? This has been done through semi structured interviews.</p><p>In conclusion, some of the dissertation’s most important features are that since the South African society, like many other societies, strongly live by the belief that there are only two sexes and genders, this implies that Intersex infants do not fit in and become walking pathologies who must be ‘fixed’ to become ‘normal’. Moreover, since most genital corrective surgeries are imposed without being medically or surgically necessary, and are generally imposed before the age of consent (18), the children concerned, are generally not asked for their opinion regarding the surgery. Lastly because early corrective surgery can have devastating life lasting consequences, this ultimately means that the child’s human rights and citizenship rights are of a concern. These conclusions do however not ignore the consequences one has to endure for the price of being ‘different’.</p>

Vast amounts of carbon are stored forest soils, a product of decaying organic matter. Increased CO2 in the atmosphere is predicted to lead to increasing global temperatures, and more extreme moisture regimes. Such increases in mean temperature could accelerate the rate of organic matter decay in soils and lead to additional release of CO2 into the atmosphere, thus exacerbating climate change. However, due to its impact on plant metabolism, high atmospheric CO2 concentrations may also lead to greater condensed tannins (CT) and reduced nitrogen (N) content in leaf litter. This reduction in litter quality has the potential to slow decay of organic matter in soil and therefore offset the accelerated decay resulting from a warmer climate. My research aimed to quantify the effects of climate and litter chemistry, specifically CT and N, on litter decay, N mineralization and associated microbes in the field. Strings of litterbags were laid on the forest floor along climate transects of mature Douglas-fir stands of coastal British Columbia rain-shadow forests. In-situ climate was monitored alongside carbon and nitrogen loss over 3.58 years of decay along three transects located at different latitudes, each transect spanning the coastal Western Hemlock and Douglas-fir biogeoclimatic zones. Microbial communities in the decaying litter and in forest soils were also analyzed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Microbial biogeography at field sites was partially influenced by climate, soil characteristics and spatial distance, but did not improve best fit decay models using climate and litter chemistry variables. Litter with greater initial CT and smaller N concentration slowed down early decay (0 - 0.58 yr) and net N mineralization. Warmer temperatures accelerated later decay (0.58 - 3.58 yr) and net N mineralization. Water-soluble CT were rapidly lost during decay, while other forms of CT were likely responsible for slower decay. The composition of fungal communities on decaying litter was affected by initial concentrations of CT and N. On a yearly basis, the slower decay of litter with high CT and reduced N content can offset accelerated rates of decay associated with warmer temperatures. Concurrent shifts in microbial communities and net N mineralization suggest potential benefits to trees. / Graduate / 2017-12-19

L'azote est essentiel au développement de toutes les cellules vivantes. Il est un des facteurs limitant de la croissance végétale. La seule source d'azote abondante est l'atmosphère contenant 80 % de diazote mais cette forme n'est assimilable que par certains procaryotes. Ces microorganismes sont capables de fixer l'azote atmosphérique sous leur forme libre ou en symbiose avec des plantes. Ainsi, ils fournissent à leur plante partenaire des substrats azotés, sous forme d'ammoniaque, tandis qu'en retour celle-ci fournit à la bactérie des substrats carbonés issus de sa photosynthèse. Il s'agit d'une association à bénéfices réciproques. Il existe deux grands types de symbiose fixatrice d'azote : la symbiose rhizobienne, impliquant diverses Protéobactéries et la symbiose actinorhizienne impliquant une Actinobactérie, Frankia. Les bactéries pénètrent les cellules des plantes pour former un nouvel organe, la nodosité dans laquelle va avoir lieu la fixation d'azote. Les bases moléculaires à l'origine de la symbiose rhizobienne sont très bien caractérisées tandis que celles de la symbiose actinorhizienne restent en grande partie inconnue, de par l'absence d'outils génétiques. Toutefois, les premières étapes de mise en place de la symbiose présentent des similarités. Les deux bactéries sont capables d'induire la déformation du poil racinaire en sécrétant un facteur déformant, le facteur Nod pour la plupart des symbioses rhizobiennes et un facteur encore non caractérisé dans le cas de la symbiose actinorhizienne. La problématique de mes travaux de thèse est de savoir si le dialogue moléculaire s'établissant entre la plante et la bactérie est basé sur des composants universels. Ce travail a utilisé deux approches. Une approche ciblée visait à mettre en évidence la fonction. Une approche non-ciblée par le biais des puces transcriptomiques chez Frankia a permis de comparer l'expression génétique entre des conditions de vie libre et des conditions de vie symbiotique. Enfin, une dernière approche a concerné les composés aromatiques chez Frankia. Il s'agissait d'établir si Frankia était capable de cataboliser différents composés aromatiques. En effet, beaucoup d'entre eux sont impliqués dans les interactions plante-bactérie, notamment dans les réactions de défense de la plante / Nitrogen is essential for cells development. It's one of the limiting factors of plant growth. The only abundant source of this component is the atmosphere which contains 80 % of dinitrogen, but this form can only be assimilated by some prokaryotes. These microorganisms are able to fix atmospheric nitrogen under freeliving condition or in symbiosis with some plants. Thus, they provide nitrogen substrates to the plant in the form of ammonium, and in return the plant provides carbon substrates from photosynthesis. It is an association with reciprocal profits for both partners. There are two major nitrogen-fixing symbioses: rhizobial symbiosis, which involves various Proteobacteria and actinorhizal symbiosis, which involves the Actinobacterium, Frankia. Bacteria enter plant root cells and develop a new organ, the nodule where nitrogen fixation takes place. Molecular bases are well characterized for rhizobial symbiosis, whereas little is known about the actinorhizal symbiosis. This fact is in part due to absence of genetic tools for Frankia. However, early steps of the interaction show some similarities. These two bacteria are able to induce root hair deformation by secreting a deforming factor, Nod factor in most rhizobial symbioses and a noncharacterized factor in the actinorhizal symbiosis. The aim of this thesis was to determine if molecular dialogue between plant and bacteria is based on universal components. This work used two approaches. One was targeted on nodC-like gene from Frankia alni ACN14a. We tried to characterize their function. Another used trancriptomic microarrays in Frankia. This technique allowed us to compare transcripts from 2 conditions: free-living cells and symbiosis. A last approach focused on aromatic compounds in Frankia. We wanted to determine if Frankia was able to use different aromatic compounds to grow. Indeed, a lot of aromatic compounds are involved in plant-bacteria interaction such as plant defense

A soja, [Glycine max (L.) Merrill] é uma das espécies com maior teor protéico, contendo cerca de 40% de proteína nos grãos. Em conseqüência disso demanda alta quantidade de nitrogênio (N), o qual pode ser suprido pelo processo de fixação biológica de nitrogênio (FBN), através da simbiose com as bactérias do gênero Bradyrhizobium. No Brasil, a FBN é capaz de suprir toda a demanda de N da cultura da soja, dispensando a aplicação de fertilizantes nitrogenados. No entanto, os caracteres relacionados à FBN não têm sido diretamente considerados em programas de melhoramento genético, em função das dificuldades inerentes às avaliações dos mesmos, que requerem a destruição das plantas. O objetivo deste trabalho foi mapear os locos de caracteres quantitativos (Quantitative Trait Loci: QTLs) dos caracteres relacionados à FBN, visando identificar associações úteis para a seleção assistida por marcadores, bem como obter outras informações sobre a base genética destes caracteres em soja. Uma população composta de 157 F2:7 linhagens endogâmicas recombinantes (Recombinant Inbred Lines RILs), derivada de um cruzamento biparental, foi genotipada com 105 marcadores microssatélites, bem como avaliada para os seguintes caracteres relacionados com a FBN: número de nódulos (NN); peso seco dos nódulos (MNS); peso médio dos nódulos secos (MNS/NN) e peso seco da parte aérea (MPAS). Utilizando o método de mapeamento por intervalo composto para múltiplas características (mCIM) foram mapeados os QTLs para os quatro caracteres. Um mapa genético foi construído com um tamanho estimado em 1.263,2 cM, correspondendo a uma cobertura de 50% do genoma. Oito regiões genômicas foram associadas com os caracteres de FBN. Quatro dessas regiões, localizadas nos grupos de ligação (GL) C1, C2, E e I, foram associadas a mais de um caráter: no GL C1 (Satt190-Satt136) foram mapeados QTLs para MNS, MNS/NN e MPAS; no GL C2 (Satt460-Satt307) foram mapeados QTLs para NN e MNS; no GL E (Satt573-SAtt185) foram mapeados QTLs para MPAS e NN; e no GL I (Satt239-Satt354) foram mapeados QTLs para MNS/NN e NN. A associação dos QTLs nos GL C1, C2 e E foi atribuída à pleiotropia, enquanto que no GL I foi atribuída à ligação gênica. Os QTLs influenciando apenas um caráter foram mapeados nos GL A2, B1, G e L: no GL A2 (Sct067-Satt589) foi mapeado um QTL para MNS/NN; no GL B1 (Satt509-Satt251) foi mapeado um QTL para NN; no GL L (Satt232-Satt418) foi mapeado um QTL para MPAS; e no GL G (Satt394-Satt288) foi mapeado um QTL para MPAS. Os QTLs explicaram, individualmente, muito pouco da variação fenotípica (R2 = 1,2% a 10,0%), sendo o QTL mais significativo mapeado no GL L para MPAS, e explicou 10,0% da variação do caráter, com um efeito aditivo de 0,57 g planta-1. Portanto, foram detectados QTLs em quatro regiões para MPAS (C1, E, G e L), em cinco regiões para NN (B1, C1, C2, E, G); em duas regiões para MNS (C1, C2) e em três regiões para MNS/NN (A2, C1, I) que explicaram 23,0%, 20,0%, 11,8% e 16,0% da variação fenotípica total, respectivamente. Estes resultados estão de acordo com as herdabilidade relativamente baixas dos caracteres (28% a 49%) e refletem a natureza complexa da FBN, que está sob influência ambiental. / Soybeans [Glycine max (L.) Merrill] is a crop with high protein content (about 40%) in the seeds. As a result, the crop demands high nitrogen (N) inputs, which can be supplied by the process of biological nitrogen fixation (BNF), through the symbiosis with bacteria of the genus Bradyrhizobium. In Brazil the BNF allows to fulfill all the demand for N; therefore N fertilizers are not required. However, the traits associated with BNF have not been directly considered in breeding programs due to the difficulties to its evaluation, which require, generally, the plant destruction. The objective of this study was to map Quantitative Trait Loci (QTLs) of traits related to BNF and to identify useful associations for marker-assisted selection, as well as to obtain other information about the genetic basis of these traits in soybeans. A population of 157 F2:7 recombinant inbred lines (RILs), derived from a two-way cross, were genotyped with 105 microsatellite markers as well as evaluated for the following traits related with BNF: number of nodes (NN); nodule dry weight (NDW); mean nodule dry weight (NDW/NN); and shoot dry weight (SDW). Using the composite interval mapping for multiple traits (mCIM) method, the QTLs were mapped for all the traits. A genetic map was constructed with an estimated size of 1,263.2 cM, covering about 50% of the genome. Eight genomic regions were associated with the four traits and four of these regions, located on linkage groups (LG) C1, C2, E and I, were associated with more than one trait: in LG C1 (Satt190-Satt136), QTLs for NDW, NDW/NN and SDW were mapped; in LG C2 (Satt460-Satt307), QTLs for NN and NDW were mapped; in GL E (Satt573-SAtt185), QTLs for SDW and NN were mapped; and in GL I (Satt239-Satt354) QTLs for NDW/NN and NN were mapped. The pleiotropy was attributed to QTL association in the LG C1, C2, and E, whereas genetic linkage was attributed to QTL association in LG I. QTLs affecting only one trait were mapped in LG A2, B1, G and L: in LG A2 (Sct067-Satt589) a QTL was mapped, for NDW/NN; in LG B1 (Satt509-Satt251) a QTL was mapped for NN; in LG L (Satt232-Satt418) a QTL was mapped for SDW; and in LG G (Satt394- Satt288) a QTL was mapped for SDW. The QTLs individually explained very little of the phenotypic variation (R2 = 1.2% to 10.0%), and the most significant QTL was mapped in the LG L, explaining 10.0% of the variation for SDW, with an additive effect of 0.57 g plant-1. Therefore, QTLs in four regions were detected for SDW (C1, E, G, and L), in five regions for NN (B1, C1, C2, E, and G), in two regions for NDW (C1, and C2) and in three regions for SDW/NN (A2, C1, and I), which explained 23.0%, 20.0%, 11.8% and 16.0% of phenotypic variation, respectively. These results are in agreement with the relatively low heritability of the traits (28% to 49%) and reflect the complex nature of BNF traits, which are influenced by the environmental effects.

O presente trabalho estudou as relações entre as taxas de fixação biológica de nitrogênio (FBN), a composição e a diversidade da comunidade de bactérias diazotróficas de vida livre em três compartimentos: solo sob a copa, filosfera e dermosfera de diferentes espécies arbóreas, sendo que dermosfera foi avaliada em apenas duas espécies. As plantas escolhidas foram Euterpe edulis (Palmito juçara) Guapira opposita (Louro-branco) e Merostachys neesii (Bambu) presentes na Floresta Ombrófila Densa (FOD) de terras baixas e montanas do Parque Estadual da Serra do Mar, no Estado de São Paulo Brasil. As taxas de FBN foram estimadas pela técnica de redução de acetileno (ARA) através da relação teórica 3:1, baseada na redução de três moles de acetileno para cada mol de N fixado, e a composição da comunidade bacteriana foi acessada pelo sequenciamento parcial do gene rRNA 16S usando pirossequenciador. Foram encontradas diferenças nas estimativas das taxas de FBN que variaram entre as espécies arbóreas e principalmente entre os substratos. Os testes de comparação de médias indicaram que, nas árvores amostradas, as taxas de FBN aumentaram na ordem: solo sob a projeção da copa, filosfera e dermosfera. A maior FBN foi observada na dermosfera de E. edulis, no PESM-Santa Virginia, durante o verão (630,12±27,28 ng N cm-2 h-1) e a menor FBN no solo de G. opposita PESM-Santa Virginia, também no verão (0,49±0,17 ng N cm-2 h-1). A FBN da serapilheira e do solo não associado com as espécies arbóreas apresentou grande variabilidade espacial nas duas áreas amostradas, mas não apresentou variações sazonais. O pirosequenciamento do gene rRNA 16S mostrou que solo sob a copa, filosfera e dermosfera das espécies arbóreas avaliadas possuem comunidades bacterianas distintas, além destas serem também influenciadas pelo local de amostragem. A comunidade epifítica da dermosfera também foi influenciada pela espécie arbórea. Foram obtidas 423210 sequências que foram agrupadas em 35216 unidades taxonômicas operacionais (UTOs), distribuídas em 32 filos, dentre os quais o mais abundante foi o filo Proteobacteria (36,6%). Dos possíveis diazotróficos observados, o filo Proteobacteria foi dominante nos três compartimentos avaliados, com predomínio da classe Alphaproteobacteria, principalmente na filosfera de M. neesii. A presença de cianobactérias foi maior na dermosfera, e Firmicutes no solo sob a projeção da copa, sugerindo que a comunidade bacteriana é altamente diversificada e tende variar espacialmente. / In this study we estimate the relationship between biological nitrogen fixation (BNF) rates and composition and diversity of free-living diazotrophic bacteria in phyllosphere and soil under the canopy of tree species, Euterpe edulis (Juçara palmito), Guapira opposita (\"Louro-branco\"),and Merostachys neesii (Bamboo) in lowland and montane dense ombrophilous forests (DOFs) at the Serra do Mar State Park, Brazil; bark was also evaluated in the first two tree species. BNF rates were estimated by acetylene reduction activity (ARA) using the 3:1 theoretical ratio, based on the reduction of three acetylene moles per each N mole fixed. Bacterial community composition was evaluated by partial 16S rRNA gene sequencing with a pyrosequencer. Analysis of variance showed highly significant estimated for BNF rates, which widely varied between tree species and especially between substrates. Mean comparison tests indicated that higher BNF rates followed the following order: soil under projected canopy, phyllosphere, and bark, respectively. The highest BNF rate was observed in E. edulis bark(630.12±27.28 ng N cm-2 h-1) and the lowest BNF rate in soil under G. opposita canopy (0.49±0.17 ng N cm-2 h-1), both at the PESMSanta Virginia site in the summer. The BNF in leaf litter and soil unassociated with tree species exhibited high spatial variability in two sampling sites, but this does not indicate a temporal trend in higher BNF rates between winter and summer. Pyrosequencing of the rRNA 16S gene showed that each component of the tree species evaluated harbors a distinct bacterial community. In bark, phyllosphere, and soil the under projected canopy of trees sampled, the results demonstrated influence by sampling site. We also observed that there was influence of tree species on the epiphytic community in bark. The 423, 210sequences obtained were grouped into35,216 operational taxonomic units (OTUs), distributed among 32 phyla, with highest abundance of Proteobacteria (36.6%). Between the possible diazotrophs observed, Proteobacteria was dominant among the three components evaluated, with predominance of the class Alphaproteobacteria, especially in M. neesii phyllosphere. The presence of cyanobacteria was higher in bark and Firmicutes in soil under projected canopy of the trees sampled, suggesting that the bacterial community is highly diverse and tends to spatially vary.

Beijerinckia sp., bactéria de vida livre fixadora de nitrogênio, comumente encontrada em solos tropicais lateríticos. A cianoficina produzida por cianobactérias é a única reserva nitrogenada intracelular descrita até hoje. O presente trabalho teve como principal objetivo verificar o acúmulo de material nitrogenado intracelular associado à Fixação Biológica de Nitrogênio em cinco isolados de Beijerinckia da rizosfera de cana-de-açúcar (Saccharum sp.). Os resultados mostraram um aumento na concentração de proteína celular total concomitantemente a atividade da nitrogenase durante a fase estacionária de todos os isolados. A fixação de nitrogênio durante esta fase sugere que o destino do nitrogênio fixado seriam os grânulos de armazenamento. A análise química desta reserva confirmou a presença de arginina em teor muito elevado em relação aos demais aminoácidos sugerindo uma reserva nitrogenada diferente da cianoficina. Em recombinantes de Escherichia coli confirmou-se um possível gene envolvido no armazenamento de material nitrogenado em Beijerinckia sp. / Beijerinckia sp. bacteria free-living nitrogen-fixing, commonly found in tropical lateritic soils. The cyanophycin produced by cyanobacteria is the only intracellular nitrogen reserve described to date. This study aimed to verify the intracellular buildup of nitrogen associated with Biological Nitrogen Fixation in five Beijerinckia isolated from the rhizosphere of sugarcane (Saccharum sp.). The results showed an increase in total cellular protein concentration concomitantly nitrogenase activity during the stationary phase of all isolates. The nitrogen fixation during this phase suggests that the fate of fixed nitrogen would be the storage granules. Chemical analysis of the reserve confirmed the presence of very high content of arginine in relation to other amino acids suggesting a different reserve of cyanophycin. In recombinant Escherichia coli confirmed a possible gene involved in nitrogen storage material in Beijerinckia sp.

Os manguezais estão localizados na interface entre o continente e o oceano em regiões intertropicais, possuindo condições ambientais únicas. O objetivo deste trabalho foi avaliar a diversidade e o potencial biotecnológico da comunidade de Pseudomonas spp. em sedimentos de manguezais com diferentes estágios de preservação, no Estado de São Paulo. A diversidade de Pseudomonas spp. foi avaliada por meio da detecção do gene 16S rRNA e do gene gacA de isolados de Pseudomonas, como também por métodos independentes de cultivo. Dos 83 isolados obtidos, 55 foram positivos para o gene gacA. De acordo com as análises de DGGE e da biblioteca de clones, os diferentes manguezais apresentam comunidades de Pseudomonas bem distintas. Entre as espécies caracterizadas, P. nitroreducens e P. fluorescens foram predominantes. Pseudomonas de manguezais halotolerantes produzem AIA, ACC deaminase, NH3, solubilizam fosfato e fixam nitrogênio. Estudos demonstraram o potencial de Pseudomonas para promoção de crescimento de milho e redução dos efeitos do estresse salino sobre a planta. / Mangroves are located at the interface of continent and ocean in intertropical regions, possessing unique environmental conditions. The objective of this study was to evaluate the diversity and biotechnological potential of Pseudomonas spp. community in mangrove sediments under different stages of preservation in the São Paulo state. Pseudomonas spp. diversity was analyzed through the detection of 16S rRNA gene and gacA gene of Pseudomonas isolates, as well as through cultive independent methods. Of the 83 isolates, 55 were positive for gacA gene. According to DGGE and clone library analysis, the different mangroves showed very distinct Pseudomonas communities. Among the characterized species by 16S rRNA gene, P. nitroreducens and P. fluorescens were dominant. Pseudomonas mangrove halotolerant produce IAA, ACC deaminase, NH3, solubilize phosphate and fix nitrogen. Studies demonstrated the potential of Pseudomonas for maize growth promotion and reduce the effects of salt stress on the plant.

Diazotróficos de vida-livre podem ser encontradas associadas à filosfera, dermosfera e rizosfera das espécies vegetais. Alguns dados sugerem que a fixação biológica de N2 (FBN) por bactérias assimbióticas representa uma entrada importante de nitrogênio nos ecossistemas tropicais, variando com as espécies vegetais e nas diferentes partes da planta. O presente trabalho teve como objetivos estimar a quantidade de N2 fixado de forma assimbiótica na filosfera, dermosfera e rizosfera sobre a copa das espécies vegetais Guapira oposita e Euterpe edulis, e avaliar a diversidade das bactérias assimbióticas, através da análise do gene rRNA 16S, em uma Restinga ,em Ubatuba, SP. O estudo foi realizado no Parque Estadual da Serra do Mar, Núcleo Picinguaba, em épocas de baixa e alta pluviosidade. A atividade da nitrogenase foi determinada pela técnica de redução do acetileno e as concentrações de etileno foram determinadas por cromatografia gasosa. A diversidade de bactérias que habitam filosfera, dermosfera e solo foi acessada por pirosequenciamento da região V4 do gene rRNA 16S. A maior fixação de N foi observada na dermosfera de E. edulis nas duas épocas de coleta (175,1± 53,4 ng cm-2 h-1; 97,2 ± 21 ng cm-2 h-1), as taxas de fixação de N mais baixas foram observadas no solo. Na época de alta pluviosidade, a FBN na filosfera de G. oposita (52,0 ± 12 ng cm-2 h-1) foi significativamente maior do que a filosfera de E. edulis (3,6 ± 06 ng cm-2. h-1) e do que no mesmo compartimento mas em diferentes épocas de coleta (7,5 ± 1,3 ng cm-2 h-1). O valor do 15N foi maior no solo onde a fixação de N foi mais baixa. Na filosfera e na dermosfera, a relação C/N foi mais baixa quando a FBN foi mais alta. A FBN no solo e serrapilheira de restinga apresentou grande variação espacial, com locais de alta atividade. As 188629 sequências obtidas foram agrupadas em 16727 Unidades Taxonômicas Operacionais (UTOs), distribuídos em 35 filos. Os principais filos detectados foram Proteobacteria (38%) e Acidobacteria (12%). As classes Alphaproteobacteria e Gammaproteobacteria foram as mais abundantes nos três compartimentos. Potenciais fixadores de N foram detectados nas classes Alpha Beta e Gammaproteobacteria. A abundância de cianobacterias fixadoras de N na filosfera e na dermosfera foi baixa, indicando que outros diazotróficos também colonizam esses ambientes e contribuem com a FBN. / Free-living N2 fixing bacteria can be found associated with the phyllosphere, bark and rizosphere of the diferent plant species. Some data suggest that biological N2 fixation (BNF) by free-living bacteria represents an important input of nitrogen in tropical ecosystem, varying with the plant species and in different parts of the plant. This study aimed to estimate the amount of N2 fixed in the phyllosphere, bark and soil under the canopy of Guapira opposite and Euterpe edullis, and evaluate the diversity of bacteria through the sequencing of the 16S rRNA gene analysis, the phyllosphere, bark and soil in a Restinga area, Ubatuba, SP. The study was conducted in the Parque Estadual da Serra do Mar, Núcleo Picinguaba in seasons of low and high rainfall. Nitrogenase activity was determined by the acetylene reduction assay (ARA) and ethylene concentrations were determined by gas chromatography. The diversity of bacteria in the phyllosphere, bark and soil was accesed using pyrosequencing of the 16S rRNA V4 region. The bark of Euterpe edullis was higher at both sampling times (175,1±53,4 ng. cm-2. h-1, 97,2±21 ng. cm-2. h-1). The BNF rates were lower in soil. In high rainfall conditions, the BNF in the phyllosphere of Guapira opposite increased significantly (52,0±12 ng. cm-2. h-1) when compared with Euterpe edullis (3,6 ± 06 ng. cm-2. h-1) and Guapira opposite (7,5 ± 1,3 ng. cm-2. h-1) phyllosphere. The value of 15N was higher in the soil where the rates of FBN was lower. In the phyllosphere and bark, C/N was lower when BNF was higher. BNF in soil great spatial variation with areas of high activity. The 18.629 sequences obtained were grouped into 16.727 Operational Taxonomic Units (OTUs) distributed in 35 phyla. The main phyla Proteobacteria represented 38% of the OTUs and Acidobacteria 12% of the UTOs. The classes Alphaproteobacteria and Gammaproteobacteria were the most abundant in the three compartmens. Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria were the main potential N-fixers. The abundance of nitrogen-fixing Cyanobacteria in the phyllosphere and bark was low, indicating that others diazotrophics also colonize these environments and contribute with BNF.

O comportamento infra-vermelho dos propagadores de glúons e de ghosts é de fundamental importância para o entendimento do limite de baixas energias da cromodinâmica quântica (QCD), especialmente no que diz respeito ao problema do confinamento de quarks e de glúons. O objetivo desta tese é implementar um novo método para o estudo do propagador de glúons no calibre covariante linear para a QCD na rede. Em particular, analisamos em detalhe a nova implementação proposta e estudamos os algoritmos para fixação numérica deste calibre. Note que a fixação numérica da condição de calibre de Feynman apresenta vários problemas não encontrados nos casos de Landau e de Coulomb, o que impossibilitou por longo tempo o seu estudo adequado. De fato, a definição considerada inicialmente, por Giusti et. al., é de difícil implementação numérica e introduz condições espúrias na fixação de calibre. Como consequência, os únicos estudos efetuados anteriormente referem-se aos propagadores de glúons e de quarks em redes relativamente pequenas, não permitindo uma análise cuidadosa do limite infra-vemelho da QCD neste calibre. A obtenção de novas soluções para a implementação do calibre de Feynman na rede é portanto de grande importância para viabilizar estudos numéricos mais sistemáticos dos propagadores e dos vértices neste calibre e, em geral, no calibre covariante linear. / The infrared behavior of gluon and ghost propagators is of fundamental importance for the understanding of the low-energy limit of quantum chromodynamics (QCD), especially with respect to the problem of the confinement of quarks and gluons. The goal of this thesis is to implement a new method to study the gluon propagator in the linear covariant gauge in lattice QCD. In particular, we analyze in detail the newly proposed implementation and study the algorithms for numerically fixing this gauge. Note that the numerical fixing of the Feynman gauge condition poses several problems that are not present in the Landau and Coulomb cases, which prevented it from being properly studied for a long time. In fact, the definition considered initially, by Giusti et. al., is of difficult numerical implementation and introduces spurious conditions into the gauge fixing. As a consequence, the only studies carried out previously involved gluon and quark propagators on relatively small lattices, hindering a careful analysis of the infrared limit of QCD in this gauge. Obtaining new solutions for the implementation of the Feynman gauge on the lattice is therefore of great importance to enable more systematic numerical studies of propagators and vertices in this gauge and, in general, in the linear covariant gauge.

Diazotróficos de vida-livre podem ser encontradas associadas à filosfera, dermosfera e rizosfera das espécies vegetais. Alguns dados sugerem que a fixação biológica de N2 (FBN) por bactérias assimbióticas representa uma entrada importante de nitrogênio nos ecossistemas tropicais, variando com as espécies vegetais e nas diferentes partes da planta. O presente trabalho teve como objetivos estimar a quantidade de N2 fixado de forma assimbiótica na filosfera, dermosfera e rizosfera sobre a copa das espécies vegetais Guapira oposita e Euterpe edulis, e avaliar a diversidade das bactérias assimbióticas, através da análise do gene rRNA 16S, em uma Restinga ,em Ubatuba, SP. O estudo foi realizado no Parque Estadual da Serra do Mar, Núcleo Picinguaba, em épocas de baixa e alta pluviosidade. A atividade da nitrogenase foi determinada pela técnica de redução do acetileno e as concentrações de etileno foram determinadas por cromatografia gasosa. A diversidade de bactérias que habitam filosfera, dermosfera e solo foi acessada por pirosequenciamento da região V4 do gene rRNA 16S. A maior fixação de N foi observada na dermosfera de E. edulis nas duas épocas de coleta (175,1± 53,4 ng cm-2 h-1; 97,2 ± 21 ng cm-2 h-1), as taxas de fixação de N mais baixas foram observadas no solo. Na época de alta pluviosidade, a FBN na filosfera de G. oposita (52,0 ± 12 ng cm-2 h-1) foi significativamente maior do que a filosfera de E. edulis (3,6 ± 06 ng cm-2. h-1) e do que no mesmo compartimento mas em diferentes épocas de coleta (7,5 ± 1,3 ng cm-2 h-1). O valor do 15N foi maior no solo onde a fixação de N foi mais baixa. Na filosfera e na dermosfera, a relação C/N foi mais baixa quando a FBN foi mais alta. A FBN no solo e serrapilheira de restinga apresentou grande variação espacial, com locais de alta atividade. As 188629 sequências obtidas foram agrupadas em 16727 Unidades Taxonômicas Operacionais (UTOs), distribuídos em 35 filos. Os principais filos detectados foram Proteobacteria (38%) e Acidobacteria (12%). As classes Alphaproteobacteria e Gammaproteobacteria foram as mais abundantes nos três compartimentos. Potenciais fixadores de N foram detectados nas classes Alpha Beta e Gammaproteobacteria. A abundância de cianobacterias fixadoras de N na filosfera e na dermosfera foi baixa, indicando que outros diazotróficos também colonizam esses ambientes e contribuem com a FBN. / Free-living N2 fixing bacteria can be found associated with the phyllosphere, bark and rizosphere of the diferent plant species. Some data suggest that biological N2 fixation (BNF) by free-living bacteria represents an important input of nitrogen in tropical ecosystem, varying with the plant species and in different parts of the plant. This study aimed to estimate the amount of N2 fixed in the phyllosphere, bark and soil under the canopy of Guapira opposite and Euterpe edullis, and evaluate the diversity of bacteria through the sequencing of the 16S rRNA gene analysis, the phyllosphere, bark and soil in a Restinga area, Ubatuba, SP. The study was conducted in the Parque Estadual da Serra do Mar, Núcleo Picinguaba in seasons of low and high rainfall. Nitrogenase activity was determined by the acetylene reduction assay (ARA) and ethylene concentrations were determined by gas chromatography. The diversity of bacteria in the phyllosphere, bark and soil was accesed using pyrosequencing of the 16S rRNA V4 region. The bark of Euterpe edullis was higher at both sampling times (175,1±53,4 ng. cm-2. h-1, 97,2±21 ng. cm-2. h-1). The BNF rates were lower in soil. In high rainfall conditions, the BNF in the phyllosphere of Guapira opposite increased significantly (52,0±12 ng. cm-2. h-1) when compared with Euterpe edullis (3,6 ± 06 ng. cm-2. h-1) and Guapira opposite (7,5 ± 1,3 ng. cm-2. h-1) phyllosphere. The value of 15N was higher in the soil where the rates of FBN was lower. In the phyllosphere and bark, C/N was lower when BNF was higher. BNF in soil great spatial variation with areas of high activity. The 18.629 sequences obtained were grouped into 16.727 Operational Taxonomic Units (OTUs) distributed in 35 phyla. The main phyla Proteobacteria represented 38% of the OTUs and Acidobacteria 12% of the UTOs. The classes Alphaproteobacteria and Gammaproteobacteria were the most abundant in the three compartmens. Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria were the main potential N-fixers. The abundance of nitrogen-fixing Cyanobacteria in the phyllosphere and bark was low, indicating that others diazotrophics also colonize these environments and contribute with BNF.