Orientadores: Leonilda Maria Barbosa dos Santos, Benito Pereira Damasceno / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-22T19:26:19Z (GMT). No. of bitstreams: 1 Silva_FelipevonGlehn_D.pdf: 6687964 bytes, checksum: 5e92607a118fbc6e4c8085aa93b540a0 (MD5) Previous issue date: 2013 / Resumo: A Neuromielite óptica (NMO) é uma doença inflamatória e desmielinizante do SNC, de natureza autoimune, caracterizada por surtos graves de neurite óptica e mielite transversa, de evolução mais freqüente na forma recidivante-remitente, com pouca remissão dos déficits entre as crises, altamente incapacitante. A presença do anticorpo anti-aquaporina 4 (anti-AQP4) foi descrito em 73% a 91% dos pacientes com diagnóstico de NMO. Doenças autoimunes podem frequentemente ser desencadeadas após infecções por micro-organismos, como agentes virais. A NMO e a infecção pelo HTLV-1 possuem prevalência coincidentemente elevada em certas áreas do globo, como o Brasil. Com o objetivo de avaliar a associação do HTLV-1 com a NMO, foi pesquisada a presença de anti-AQP4 e anti-HTLV-1 em 34 pacientes com DENMO, 43 pacientes infectados com HTLV-1, assintomáticos ou com a doença mielopatia associada ao HTLV-1 (HAM/TSP) e 23 controles sadios. Nenhum paciente com DENMO apresentou sorologia positiva para HTLV-1. Nenhum paciente infectado pelo HTLV-1 apresentou soropositividade para anti-AQP4. 60% dos casos de DENMO foram positivos para anti-AQP4. Esses resultados sugerem que a mielopatia associada à variante aguda da HAM/TSP e aquela associada ao anticorpo anti-AQP4 são entidades clínicas distintas, e provalvemente, não relacionadas de forma patogênica ao HTLV-1 em nosso meio. O cérebro humano expressa amplamente AQP4, mas estudos anatomopatológicos e de neuroimagem não detectaram lesões corticais desmielinizantes ou infiltrados inflamatórios no DENMO. A fim de avaliar melhor a presença de alterações estruturais nas substâncias cinzenta e branca encefálicas no DENMO, foram estudados 34 pacientes por RNM de 3T e tomografia de coerência óptica retiniana pareados com controles sadios, divididos nas apresentações NMO, mielite transversa longitudinal extensa (MTLE) e neurite óptica (NO), além de soropositivos versus soronegativo para anti-AQP4 e 5 anos ou menos de doença versus mais de 5 anos de doença. Houve maior grau de atrofia retiniana nos grupos NMO e NO, além dos grupos anti-AQP4+ e mais de 5 anos de doença. Foi constatado maior grau de atrofia cortical cerebral e estruturas da substância branca nos grupos NMO e MTLE, anti-AQP4+ e mais de 5 anos de doença. A atrofia retiniana se correlacionou positivamente com a atrofia do lobo occipital. Esses dados sugerem que o DENMO está associado à atrofia de estruturas das substâncias cinzenta e branca cerebrais; que a atrofia não se limita apenas às áreas das vias sensorial, motora e visual, mas é mais difusa; que quanto maior o tempo de doença e a presença do anticorpo anti-AQP4, maior é o grau de atrofia cortical, configurando estes fatores, tempo e anti-AQP4+, como de pior prognóstico; e a correlação positiva entre atrofia da camada de fibras nervosas retinianas e atrofia pericalcarina, além da escala de incapacidade funcional expandida (EDSS), sugere que a degeneração neuronal retrógrada e/ou anterógrada do tipo Walleriana é um importante causador da atrofia cortical no DENMO / Abstract: Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system (CNS) of putative autoimmune aetiology, which is characterized by severe attacks of myelitis and optic neuritis (ON). A relapsing course with rapid accumulation of neurological deficits with little or no remission is common. The NMO is autoimmune in nature and antibodies to Aquaporin 4 (AQP4) are associated with the development of the disease. AQP4 is the most common water channel protein of CNS; present in astrocytes processes, endothelium and piamater meninges. It predominates at some sites of the CNS, as optic nerve, brain stem and gray matter of medulla, the same sites of the usual inflammatory lesions. Autoimmune diseases may be triggered by microorganism infections and NMO and HTLV-1 infection have coincidentally high prevalence in certain areas of the world including Brazil. To study a possible relationship between these two diseases, we determined the seroprevalence of antibodies to AQP4 in 43 patients with HTLV-1 infection, asymptomatic or with HTLV-1 associated myelopathy (HAM/TSP) and that of HTLV-1 antibodies in patients with neuromyelitis optica spectrum disorders (NMOSD). AQP4ab positivity was found in 60% of NMOSD patients, but in none of the HAM/TSP patients and none of the asymptomatic HTLV-1 infected individuals. Conversely, all AQP4-Ab-positive NMOSD patients were negative for HTLV-1 antibodies. The results argue both against a role of antibodies to AQP4 in the pathogenesis of HAM/TSP and against an association between HTLV-1 infection and the development of AQP4-Ab. Moreover, the absence of HTLV-1 in all patients with NMOSD suggests that HTLV-1 is not a common trigger of acute attacks in patients with AQP4-Ab positive NMOSD in populations with high HTLV-1 seroprevalence. Although AQP4 is also expressed widely in the human brain cortex, beyond the common sites of lesions in NMO, recent studies have found no MRI or histopathological evidence for cortical demyelination. To investigate magnetic resonance imaging (MRI) patterns of gray matter (GM) and white matter (WM) abnormalities in patients with NMO and its incomplete forms, isolated longitudinally extensive transverse myelitis and optic neuritis, and to assess the prognostic impact of GM and WM abnormalities in these conditions, we performed both 3T high-resolution T1-weighted and diffusion tensor MRI in thirty-four patients with NMO spectrum disorders (NMOSD) and 34 matched healthy controls. Voxel-based morphometry (SPM8/MATLAB2012b), cortical analyses (Freesurfer), and diffusion tensor imaging analyses (TBSS-FSL) were used to investigate brain abnormalities. In addition, retinal nerve fiber layer was measured by means of optic coherence tomography (OCT). These analyses resulted in following findings: (1) NMOSD is associated with GM and WM atrophy, which encompasses more brain structures than the motor, sensory, and visual pathways; (2) this atrophy is more widespread in patients with NMO and LETM than in patients with ON; (3) the extent of GM atrophy correlates with disease duration, and (4) GM/WM atrophy in NMOSD is more pronounced in AQP4 antibody-seropositive than in -seronegative patients. Furthermore, it was demonstrated for the first time in NMOSD a correlation between RNFL atrophy and GM atrophy in the occipital lobes as assessed by OCT, indicating a role for retrograde degeneration in GM atrophy and suggesting that the extent of brain GM/WM atrophy may be of prognostic relevance in NMOSD / Doutorado / Neurologia / Doutor em Ciências Médicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Feed supplementation of the animals affects the pasture intake and may influence its productive and structural characteristics. Morphogenesis is a valuable tool for the dynamics understanding of the pasture, however the morphogenetic studies related to sorghum culture are still scarce as well as the evaluation of the supplementation effects on these characteristics. The objective of the present study was to evaluate the effects of the different levels of supplementation on the morphogenetic characteristics of sorghum forage (Sorghum bicolor (L.) Moench) submitted to continuous grazing of beef steers. The experiment was performed at the Beef Cattle Laboratory of UFSM from January to April, 2013. Morphogenetic measures were taken by the marked tiller technique in order to determine the morphogenetic variables of sorghum forage. The completely randomized experimental design was used, with measures repeated in time, with three treatments and two repetitions (area) for the morphogenetic characteristics. The results of the morphogenetic variables were submitted to variance analysis with 5% of significance level using PROC MIXED. The analyses were performed with the assistance of the statistical package SAS 9.1.3 (2009). By increasing the supplementation level offered to the animals it was observed a lower value for the Number of Live Leafs (2.77, 3.34 and 3.55) and Leaf Elongation Rate (0.06, 0.09 and 0.08) characteristics. The variables Leaf Appearance Rate (0.0041, 0.0043 and 0.039), Leaf Senescence Rate (0.05, 0.06 and 0.11) and Phyllochron (283.96, 265.21 and 278.62) were not influenced by the different supplementation levels. There was a difference among the evaluation periods for the characteristics Leaf Life Span (1081.1, 986.25 and 788.79) and Leaf Elongation Length (350.58, 312.83 and 326.36). For the characteristics Canopy Height, Pseudo Stem Length, and Final Length of Blades there was an interaction between treatment and period. / A suplementação alimentar dos animais afeta o consumo do pasto e pode influenciar suas caraterísticas produtivas e estruturais. A morfogênese é uma valiosa ferramenta para a compreensão da dinâmica do pasto, porém os estudos morfogênicos referentes à cultura do sorgo ainda são escassos, bem como a avaliação dos efeitos da suplementação sobre estas características. O objetivo do presente estudo foi avaliar os efeitos de diferentes níveis de suplementação sobre as características morfogênicas do sorgo forrageiro (Sorghum bicolor (L.) Moench) submetido ao pastejo contínuo de novilhos de corte. O experimento foi conduzido no Laboratório de Bovinocultura de Corte da UFSM no período de janeiro a abril de 2013. Foram tomadas medidas morfogênicas pela técnica de perfilhos marcados para determinação das variáveis morfogênicas do sorgo forrageiro. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo, com três tratamentos e duas repetições (área) para as características morfogênicas. Os resultados das variáveis morfogênicas foram submetidos à análise de variância em nível de 5% de significância, utilizando o PROC MIXED. As análises foram realizadas com auxílio do pacote estatístico SAS 9.1.3 (2009). Ao aumentar o nível de suplementação ofertado aos animais, observou-se menor valor para as características de Folhas Vivas (2,77, 3,34 e 3,55) e Taxa de Alongamento Foliar (0,06 0,09 e 0,08). Não foram influenciadas pelos diferentes níveis de suplementação as variáveis Taxa de Aparecimento Foliar (0,0041, 0,0043 e 0,039), Taxa de Senescência Foliar (0,05, 0,06 e 0,11), Filocrono (283,96, 265,21 e 278,62). Para as características Duração de Vida da Folha (1081,1, 986,25 e 788,79) e Duração de Elongação Foliar (350,58, 312,83 e 326,36) houve diferença entre os períodos de avaliação. Para as características Altura de Dossel, Comprimento de Pseudocolmo e Comprimento Final de Laminas houve interação entre tratamento e período.

Fire ecology encompasses the study of the factors, biotic and abiotic, that influence the occurrence of fire in an area, as well as the effects fire has on the flora and fauna native and non-native to the region (Whelan 1995). Fire has had a major influence on shaping biomes as we see them today. Fire has had an effect on vegetation much before the evolution of Homo on Earth (Keeley and Rundel 2005, Pausas and Keeley 2009, Midgley and Bond 2011). With the evolution and expansion of Homo across Earth, fire has been tamed, and then generated and used over time to yield landscapes that were suitable for their existence (Pyne 1991, Bowman et al. 2009, Archibald et al. 2012). Thus, fire, vegetation and humans were, and still are, inextricably linked in certain biomes on Earth. The best examples are observed in tropical savannas and grasslands, biomes that experience distinct seasonality in climate and are thus prone to frequent fires caused either by lightning or by humans (Keeley and Rundel 2005, Archibald et al. 2012). At the other end of the spectrum of tropical vegetation types are rainforests where the occurrence of fires is constrained by a perpetually moist environment (Meyn et al. 2007, van der Werf et al. 2008), in the absence of manipulation of the forest landscape by humans. Frequent fires have been documented to alter structure and cause a decline in forest diversity in rainforests (Cochrane and Schulze 1999, Cochrane 2003), whereas fire exclusion in mesic savannas leads to increases in biomass and transition to forest ecosystems (Bond et al. 2003, Bond et al. 2005 and references therein). A tropical biome that lies between these two extremes of vegetation types is the Seasonally Dry Tropical Forest (SDTF) where the occurrence of fire is common, but for which there are contrasting views on the effect of fire on this system (Saha and Howe 2003, Otterstrom et al. 2006 as examples). Current forest management policies in SDTF areas, especially in India, actively aim to exclude fire from these forests mostly because of the perception held by forest managers and the general public that fire has negative effects on forests. However, very few scientific studies have explored the ecology of fire in SDTFs. In order to formulate fire management policies, it is necessary to have a more comprehensive understanding of the ecology of fire in this tropical forest type. This thesis addresses two components of fire ecology as applied to SDTFs. The first is how fire is influenced by the environment, and the second, how fires influence the biotic community particular to SDTFs. The study was carried out in an SDTF in southern India where fire is a common occurrence -the forests of Mudumalai – a protected area that exhibits a range of SDTF vegetation types, from moist deciduous to dry thorn forest, corresponding to a rainfall gradient. Fire influenced by the environment: For this section, the influence of fuel load, fuel moisture and ambient weather on area burnt, fire occurrence and fire temperatures were studied in the SDTF vegetation types of Mudumalai. The extent of fire (area burnt) in an ecosystem differs according to the relative contribution of fuel load and fuel moisture available (Meyn et al. 2007). At a global scale, these factors vary along a spatial gradient of climatic conditions and are thus “varying constraints” (Krawchuk and Moritz 2011) on fire activity in natural ecosystems (Meyn et al. 2007, Krawchuk and Moritz 2011). Moist ecosystems such as tropical rainforests are at one end of the spectrum where fire activity is constrained by fuel moisture. At the other end are arid ecosystems, such as deserts, where fire activity is limited by the presence of fuels. The potential for the globally widespread seasonally dry tropical forests (SDTFs) to be placed as a single entity in this framework was examined by analyzing the interacting effects of fuel load and fuel moisture on the extent of fire in Mudumalai. Logistic regression was used to model proportion area burnt in a given year with factors that would influence fuel load and fuel moisture – these were proportion area burnt the previous year, wet season rainfall the previous year and early dry season rainfall. Modelling was conducted at two levels – the overall landscape and within four defined moisture regimes (between 700 and 1700 mm yr-1) – using a dataset of area burnt and seasonal rainfall from 1990 to 2010. The landscape scale model showed that the extent of fire in a given year within this SDTF is dependent on the combined interaction of seasonal rainfall and extent burnt the previous year. However, within individual moisture regimes the relative contribution of these factors to the annual extent burnt varied – early dry season rainfall (i.e. a moderator of fuel moisture) was the predominant factor in the wettest regime, while the previous year’s wet season rainfall (i.e. a proxy for fuel load) had a large influence on fire extent in the driest regime. Thus, the diverse structural vegetation types associated with SDTFs across a wide range of rainfall regimes would have to be examined at finer regional or local scales to understand the specific environmental drivers of fire. While the extent burnt in SDTFs is largely dependent on climatic influences, the probability of ignition has not been characterized for SDTFs. Anthropogenic fires are a regular occurrence during the dry season in SDTFs (Stott et al. 1990). We investigated if the occurrences of anthropogenic fire in Mudumalai were associated with any particular weather conditions during the dry season. Logistic regression between probability of a fire day and weather variables -seasonal rainfall, ambient relative humidity and temperature -was examined during the dry seasons of 20042010 in Mudumalai. Fire incidence data was obtained from the Fire Information for Resource Management System (FIRMS; NASA 2002) and weather data from two automatic weather stations within Mudumalai. The analysis showed that days with high probabilities of fire occurrence were associated with low levels of early dry season rainfall, low daily average relative humidity, and high daily average temperatures. These weather conditions are known to influence moisture levels of fine fuels (Viney 1991, Archibald et al. 2009). In Mudumalai as well as other SDTFs the primary fuels for fires are fine fuels such as litter and dried grass that accumulate on the forest floor during the dry season. Our results suggest that the occurrence of fire is moderated by environmental conditions that reduce or enhance the flammability of fine fuels in the dry tropics. A quantitative framework for assessing risk of a fire day has been proposed as an outcome of this analysis to assist forest managers in anticipating fire occurrences in this SDTF, and possibly for those across south Asia. Of the various components of a fire regime, fire intensity is an important aspect. High fire temperatures (one measure of fire intensity, Keeley 2009) and resulting soil temperatures would have an effect on soil properties as well as plant species demography and community structure (Moreno and Oechel 1991, Neary et al. 1999, Morrison 2002). Fires that occur frequently in a region could vary in their intensity and severity depending upon the amount of fuel available and ambient weather conditions (Stinson and Wright 1969, Stott 1986, Stronach and McNaughton 1989, Ansley et al. 1998, Wotton et al. 2012). However, this relationship has not been examined in a multiple regression framework for SDTFs. Fire temperature was recorded and its relationship with ambient weather and fuel load was studied in two SDTFs of southern India -Mudumalai and Biligiri Rangaswamy Temple (BRT) Wildlife Sanctuary in Karnataka. During “controlled burns” conducted by the forest department staff in these reserves in February and March 2010, temperature indicating lacquers on mica sheets were used to measure fire temperature at several points at ground level and one cm below the ground. Biomass was harvested close to the temperature measurement points to estimate fuel load and fuel moisture. Ambient weather conditions were recorded during the controlled burn when the flame passed over the indicators. Temperatures recorded at ground level ranged from <79oC to 760oC, with the most frequently recorded temperatures between 343-399 oC and 510566 oC. Temperatures measured one cm below the ground ranged from <79oC to 302oC, with a majority of the indicators recording temperatures in the <79oC category. Ground-level temperatures increased with increasing biomass. A linear regression of ground-level temperatures with fuel load and ambient weather conditions of relative humidity and temperature was found to explain most of the variation in the data. Ground-level fire temperatures increased with increasing fuel load, but were also found to be lower at higher relative humidities at a given temperature. In order to reduce the intensity of forest fires that occur accidentally during the dry season, we recommend that fuel loads be reduced in the forest by prescribed burning early in the dry season. This applies especially to areas where there is accumulation of biomass over years, such as that of the tall grass Themeda cymbaria found predominantly in dry deciduous forest types. If prescribed burning is incorporated in fire management policies for these forests, then the season of burning will be important to consider. It is known from ecosystems where prescribed burning is regularly applied that early dry season fires are less intense than late dry season fires (Williams et al. 1998). However, this has not been systematically investigated for SDTFs. Through a burning experiment carried out in private land with vegetation type similar to tropical dry thorn forest, we investigated differences in area burnt, ground-level fire temperatures and soil temperatures one cm below the ground in the early dry season in January, late dry season in April and and early wet season in June. We also examined differences in fuel load, fuel moisture, soil moisture and weather conditions of ambient relative humidity (RH), temperature and wind speed in these phases; these factors could be responsible for observed differences in fire and soil temperatures or area burnt. Although area burnt was not significantly different between the early and late phases of the dry season, fire and soil temperatures were significantly lower in the former. The late dry season was characterized by distinctly higher fuel loads, lower fuel moisture, lower relative humidity, higher ambient temperatures and higher wind speeds compared that measured in the early dry season. Differences in soil temperature between these months may be attributed to the increase in fuel load since there were no significant differences in soil moisture. Fire spread was limited in the experimental plots in the early wet season in June, probably due to significantly higher levels of fuel moisture in this month; the resultant fire and soil temperatures recorded were low. Forest management should, therefore, consider early dry season burns in the month of January for prescribed burns in the sanctuary, although this would have to be tested in other SDTF vegetation types with more variable fuel load, fuel moisture and weather conditions. Fire’s influence on the biotic community: Concerns regarding the regeneration capacity of woody species in SDTFs have been voiced with respect to increasing frequencies of fire (Saha and Howe 2006, Kodandapani et al. 2008). Fire is known to cause high mortality of individuals of small size (Swaine et al. 1990, Suresh et al. 2010). However, mortality has been examined for large size classes, and not for seedlings. It is essential to understand the dynamics of seedlings and their contribution to the regeneration potential of SDTFs. Woody species in SDTFs are known to have traits that help them recover from recurring disturbances, such as sprouting from underground root stocks (Vieira and Scariot 2006). Another trait may relate to growth rates of seedlings. Growth rates of seedlings (defined in this study as established individuals between 10 and 100cm height) after dry season (February-March) fires were compared between adjacent pairs of burnt and unburnt transects established at eight sites in Mudumalai across vegetation types of moist deciduous, dry deciduous and dry thorn forest. The growth of grasses, a possible competitor for resources, was also monitored at each site. Seedling and grass heights were monitored at 3-month intervals between August 2009 and August 2010. A second fire in March 2010 affected transects at two sites in Mudumalai. Seedling and grass heights were monitored for two enumerations till August 2010 subsequent to the second fire at these two sites. A total of 1032 individuals across 58 woody species were enumerated. High seedling survivorship (>95%) was observed in both burnt and unburnt areas. Although seedling heights were significantly different between burnt and unburnt areas at the start of the enumeration in August 2009, heights were comparable within a year and a half of the fire. Comparable seedling heights in such a short time span were because of distinctly higher growth rates of seedlings in burnt areas compared to unburnt areas after the fire event, particularly during the pre-monsoon season. Grass biomass (volume), on the other hand, was significantly different between burnt and unburnt areas at both the first and last enumerations. Grass growth (change in volume) did not differ between burnt and unburnt areas. Rapid growth by seedlings after a fire implies adaptation through the use of stored resources for growth, possibly aided by lower competition from grasses, in order to attain a certain size before the subsequent return of unfavourable factors such as a recurrent fire event. Conclusions: The results from the study point to climatically driven fire regimes in an SDTF in southern India, with daily influences of weather conditions during the dry season on fire occurrences. Fire intensities increase with increasing fuel loads in these forests, moderated by weather conditions such as RH and temperature. Since fires are an anthropogenic phenomenon in these forests, active management with the use of prescribed fires in the early phase of the dry season is a possible option to control late dry season fires that would be higher in intensity. The current woody tree species assemblage in this southern Indian SDTF is resilient to fires at the seedling stage, with established individuals exhibiting high survivorship and rapid growth after a fire. However, the effects of fires of varying intensities on the regenerative capacity of the seedlings are not known. The effect of fire on habitat utilisation by large herbivores, or the impact of fire on the faunal community in general has not been studied for vegetation types that comprise SDTFs. The effect of fire exclusion on the ecology of SDTFs will provide useful information that can feed into management policies for this ecosystem type. These are potential areas of research for the future. Fire, if managed wisely, can be an effective tool for the conservation of SDTFs across south and southeast Asia.

Em 2007 o Painel Intergovernamental Sobre Mudanças Climáticas relataram mudanças climáticas nas últimas décadas, principalmente aumento de temperatura. Tal fato tem preocupado cientistas sobre o futuro. Assim, estudos tem sido realizados para avaliar possíveis impactos na agropecuária. As pastagens no Brasil podem ser particularmente afetadas, devido a grande extensão de terras ocupadas, muitas delas em áreas marginais. No estado de São Paulo, estas mudanças poderão ser importantes para a Braquiaria brizantha cv. Marandu, gênero presente em cerca de 7,19 milhões de hectares. Assim, objetivou-se avaliar impactos das mudanças climáticas na produção desta forrageira em São Paulo. As projeções foram realizadas com base nos modelos climáticos regionalizados PRECIS e ETA-CPTEC, considerando os cenários de emissões do IPCC A2 (alta) e B2 (baixa). Os dados do período de 1963 a 2009 de 23 estações meteorológicas foram considerados como o clima atual (CA). Os períodos simulados foram de 2013 a 2040 e de 2043 a 2070. Para associar clima com crescimento de capim-marandu, foi utilizado o modelo empírico de Cruz e colaboradores: TAF=15.34*GDcorrigido (p=0.056, r²=0.95), onde TAF é a taxa diária de acúmulo de forragem; GDcorrigido é o grau-dia, calculado com 17,2°C de temperatura-base e corrigido por um fator de penalização hídrico (obtido pela relação armazenamento de água atual/máximo do solo, considerando três capacidades: 40, 60 e 100 mm). Interpolação espacial foi realizada usando os métodos do vizinho natural e krigagem, com auxílio do software ArcGis 10.1. Análises regionais foram realizadas com base no censo LUPA. Em geral, as projeções mostraram aumento futuro na produção potencial. Considerando o CA, o acúmulo anual de forragem médio (AAF) foi 18,4; 19,6 e 21,0 Mg MS/ha/ano em solos com capacidade de 40, 60 e 100 mm, respectivamente. Nesta mesma ordem, foram simuladas AAF de 26,3; 27,9 e 29,8 para o PRECIS (aumento médio de 42%) e 25,0; 26,6 e 28,7 Mg MS/ha/ano para o ETA-CPTEC (aumento médio de 36%), em cenário A2 para 2043-2070. Outras projeções indicam aumentos intermediários. Apesar do aumento anual, a variação irá aumentar entre estações e entre anos. O aumento absoluto será maior na estação chuvosa, tornando a estacionalidade de produção mais marcante. Tal resultado é mais evidente nas simulações com o modelo ETA-CPTEC e para solos com menor capacidade (40 mm). Nestes solos, a TAF mínima e máxima (kg MS/ha/dia) foram, respectivamente, 15,4 (inverno) e 94,6 (verão) para o CA; 22,9 (inverno) e 125,1 (verão) para o PRECIS e 18,2 (inverno) e 125,9 (verão) para o ETA-CPTEC, em cenário A2 para 2043-2070. Os resultados variaram muito entre regiões, especialmente para cenários do ETA-CPTEC (extremos variaram de <+10% até >+60%). Regiões mais quentes (oeste do estado, em geral) tem maior potencial de produção, porém terão menor incremento relativo no futuro. Os resultados são devidos ao aumento de temperatura em geral e redução da disponibilidade hídrica, principalmente na primavera, devido a maior evapotranspiração e não necessariamente à redução da precipitação. Estratégias para mitigação e adaptação foram sugeridas, principalmente relacionadas ao manejo da pastagem e dos animais para redução dos efeitos da menor disponibilidade hídrica, redução das emissões de gases de efeito estufa e uso da forragem excedente de verão. / In 2007 the Intergovernmental Panel on Climate Change presented data showing climate changes in last decades, mainly temperature increase. This change has worried scientists about the future. Therefore, studies have been made to evaluate possible impacts of future climate changes on agricultural production. The pastures in Brazil can be especially affected, because they occupy large areas, many of them on marginal land. In São Paulo state these changes can be important for palisadegrass (Brachiaria brizantha cv. Marandu), present in 7.19 million ha. Therefore, this research evaluated the impacts of climate change on palisadegrass yield in São Paulo state. Projections were created based on downscaled outputs of two general circulation models (PRECIS and ETA-CPTEC) considering the IPCC SRES scenarios A2 (high) and B2 (low). The data obtained from 23 weather stations from 1963 to 2009 was considered as current climate (base line) and future scenarios were determined from 2013 to 2040 and from 2043 to 2070. To associate the climate with palisadegrass growth, the following empirical model was used: DMAR=15.34*DDadjusted (p=0.056, r²=0.95), extracted from research conducted in São Carlos-SP-Brazil, where DMAR is dry matter accumulation rate; DDadjusted is degree days, calculated with 17.2°C of base temperature and adjusted by one drought attenuation factor (obtained by the ratio actual/maximum soil water storage, considering three soils capacities: 40, 60 and 100 mm). Spatial interpolation was carried out using natural neighbor and kriging methods, with ArcGis 10.1 software tools. Regional analyses were realized based on the LUPA/SP census. In general, the projections showed increase on future yield potential. On soils with 40, 60 and 100 mm of storage capacity, the average annual accumulation (AAA) was, respectively, 18.4, 19.6 and 21.0 using base line data, 26.3, 27.9 and 29.8 using PRECIS output (increase about 42%) and 25.0, 26.6 and 28.7 Mg DM/ha/ano using ETA-CPTEC output (increase about 36%), considering A2 scenario in period of 2043 to 2070. The other projections show intermediate increases. Despite annual yield increase, the variation between seasons (seasonality) and years will increase. The increase in DMAR will be higher in rainy than dry season, especially in soils with low water storage capacity (40 mm) (mainly evidenced by ETA-CPTEC scenarios). For these soils, minimum and maximum DMAR (kg DM/ha/day) was respectively 15.4 (winter) and 94.6 (summer) considering base line, 22.9 (winter) and 125.1 (summer) considering PRECIS model and 18.2 (winter) and 125.9 (summer) considering ETA model, both in A2 for 2043 to 2070 scenario. The results varied a lot between regions, especially in ETA-CPTEC scenarios (extremes ranged from <+10% to >+60%). Warmer regions (west region, in general) showed higher production potential, but they will have lower relative increase in the future. These results are due to increase in temperature in all long year and decrease in water availability in winter and spring, due to higher evapotranspiration and not necessarily decrease in rain. Strategies for mitigation and adaptation were suggested, including mainly pasture and animal management to reduce effects of lower water availability, reduce greenhouse gases emissions and use of summer forage surplus.

As pastagens que cobrem uma importante área no território mundial apresentam elevado potencial de produtividade e suas características bioquímicas podem gerar relevante impacto na produção de ruminantes. Porém, poucos trabalhos relatam a concentração de compostos bioquímicos em pastagens tropicais comumente usadas na produção animal. Diante deste fato, o capítulo II desta tese teve como objetivo elucidar e determinar a concentração de taninos condensados e tocoferol, bem como avaliar a produção e os valores nutritivos de espécies forrageiras tropicais normalmente usadas em sistemas de pastejo. Com este estudo foi possível constatar que algumas espécies de gramíneas e leguminosas se destacam não apenas pela sua capacidade de produção de biomassa e qualidade nutricional, mas também pela concentração de compostos bioquímicos, como a gramínea tifton que teve elevada concentração de α-tocoferol (202.3 ± 116.5 mg/kg matéria verde, MV). As leguminosas amendoim forrageiro (15.7 ± 5.2 g/kg matéria seca, MS) e feijão guandu (8.7 ± 0.8 g/kg MS) apresentaram boa concentração de taninos condensados, mas o grande destaque foi para a leguminosa nativa pega-pega (66.5 ± 13.8 g/kg MS) que além da alta concentração de taninos, esses apresentaram potencial para atividade biológica (PPF = 60.1 g/kg MS) Aliado as características bioquímicas, as espécies que irão compor o sistema de produção podem influenciar na biologia de vida livre dos nematoides parasitas do trato gastrintestinal (NGI) e no comportamento ingestivo dos animais. O capítulo III e IV avaliam três diferentes sistemas de alimentação de cordeiros em pastagens tropicais. O capítulo III traz como objetivo avaliar a distribuição de larvas infectantes (L3) em diferentes perfis de pastagem tropical (gramíneas e leguminosas) e o impacto da contaminação da pastagem na carga parasitária e desempenho de cordeiros. Onde, a inclusão da leguminosa tropical alterou a concentração de larvas infectantes na pastagem e a contaminação dos animais. No capítulo IV é apresentado o trabalho que teve como objetivo avaliar o comportamento ingestivo de cordeiros em condições de pastejo contínuo submetidos a diferentes sistemas de alimentação com a presença de leguminosa tropical contendo taninos condensados. Apesar da diferença estrutural e concentração de taninos condensados, de modo geral essas características da pastagem não alteraram o comportamento ingestivo dos cordeiros. / Pastures covering an important area in the world territory present high production potential and their biochemical characteristics can generate a significant impact on the production of ruminants. However, few studies report the concentration of biochemical compounds in tropical pastures commonly used in animal production. Facing this fact, chapter II of this thesis had as objective to elucidate and to determine the concentration of condensed tannins and tocopherol, as well as to evaluate the production and nutritional values of tropical forage species normally used in grazing systems. In this study, it was possible to verify that some species of grasses and legumes stand out not only for their mass production capacity and nutritional quality, but also for the concentration of secondary compounds, such as tifton grass, which had a high α-tocopherol concentration (202.3 ± 116.5 mg / kg green matter, GM). The forage peanut legumes (15.7 ± 5.2 g / kg dry matter, DM) and pigeon pea (8.7 ± 0.8 g / kg DM) had an excellent concentration of condensed tannins, but the main highlight was the native legume Desmodium incunum (66.5 ± 13.8 g / kg DM) that in addition to the high concentration of tannins, these had potential for biological activity (PPP = 60.1 g / kg DM) In addition to the biochemical characteristics, the species that will make up the production system can influence the ecology of the free-living stages of endoparasite of the gastrointestinal tract (NGI) and the ingestive behavior of the animals. Chapter III and IV evaluate three different feeding systems of lambs in tropical pastures. Chapter III aims to evaluate L3 distribution in different tropical pasture (grass and legume) profiles and the impact of pasture contamination on lamb parasitic loads and production performance. Where the inclusion of the tropical legume changed the concentration of infective larvae in the pasture and the contamination of the animals. Chapter IV presents the work that aimed to evaluate the ingestive behavior of lambs under continuous grazing conditions submitted to different feeding systems with the presence of tropical legume containing condensed tannins. Despite the structural difference and concentration of condensed tannins, in general these pasture characteristics did not alter the ingestive behavior of the lambs.

L’environnement climatique est l’un des facteurs pouvant influencer la performance aérobie. Il existe des températures idéales avec lesquelles les athlètes réalisent de meilleures performances : entre 10 et 12°C en course à pied (Maughan et coll. 2010) ou inférieures à 32°C en cyclisme (Peiffer & Abbiss 2011). Davies et coll. (2016) condensent dans une métaanalyse différentes études portant sur le contre la montre (CLM) en cyclisme en environnement chaud et relèvent que la performance est altérée en climat chaud à partir du milieu de l’épreuve (P < 0,02) et jusqu’à la fin (P = 0,01) par rapport à une condition contrôle.Ce résultat laisse donc apparaitre qu’outre la température environnementale, la durée de l’effort peut également être déterminante dans l’impact du climat sur la performance. L’élévation de la température n’est pas le seul facteur environnemental pouvant influencer la performance. Maughan et coll. (2012) mettent en évidence qu’au plus le taux d’humidité est élevé au plus la performance aérobie est détériorée. Dans cette étude, des athlètes non acclimatés, réalisent une épreuve à vélo à 70% de VO2max jusqu’à épuisement lors de quatre sessions à 24, 40, 60 et 80% d’HR (T: 30°C). Les résultats, montrent que le temps d’exercice diminue significativement avec l’augmentation du taux d’humidité (P < 0,05).A travers ce travail de recherche nous avons donc investigué la question : comment faire pour limiter cet impact du climat sur la performance ?Pour ce faire 3 axes sont développés à travers nos études :a. Etudier l’efficacité de protocoles de refroidissement à plusieurs moments de la performance : avant, pendant et entre deux efforts consécutif.b. Déterminer si les combinaisons de froid peuvent se combiner.c. Déterminer si l’utilisation du menthol peut permettre une optimisation des protocoles de cooling.Les principaux résultats de cette thèse mettent en évidence que l’utilisation de méthodes de cooling est efficace mais que cette efficacité dépend du protocole utilisé. Nous avons ainsi mis en évidence (1) Qu’en pré-cooling il est nécessaire de débuter 1h avant l’effort pour avoir une efficacité de la méthode ; (2) Qu’une immersion avec du menthol est plus efficace qu’une immersion seule entre deux efforts de 20’ mais qu’utilisé sur des vêtements son efficacité n’est pas prouvée; (3) Que le port d’un gilet froid cumulé à une ingestion d’une boisson froide à l’échauffement n’est pas plus efficace qu’un refroidissement interne seul (4) Que le menthol peut influencer les performances en jouant un rôle sur le SNC.L’action du menthol va permettre au SNC de percevoir l’environnement comme étant « plus favorable » et par conséquent entrainer une modification de la rétroaction thermorégulatrice, et ainsi permettre une meilleure performance. Cela sans que le menthol ne joue un rôle délétère à la thermorégulation. / The climatic environment is one of the factors that can influence the aerobic performance. There are an ideal temperatures with which athletes realize better performance: between 10 and 12°C in running (Maughan et al. 2010) below 32°C in cycling (Peiffer & Abbiss 2011). Davies et al. (2016) condense in a meta-analysis different studies on time trial (TT) in cycling and note that the performance is impaired in hot weather from middle of the test (P <0.02) and until the end (P = 0.01) compared to a condition control. This result therefore shows that in addition to the environmental temperature, the duration of the effort can also be decisive in the impact of climate on the performance.Rising temperature is not the only environmental factor that can influence the performance. Maughan et al. (2012) highlight that at the highest level of humidity is high at most aerobic performance is deteriorated. In this study, non-athletes acclimatized, perform a 70% VO2max bike test until exhaustion four sessions at 24, 40, 60 and 80% RH (T: 30 ° C). The results show that time exercise decreased significantly with increasing humidity (P <0.05). Through this research work we therefore investigated the question: how to do to limit this impact of climate on performance?To do this, 3 axes are developed through our studies: a. Study the effectiveness of cooling protocols at several points in the performance: before, during and between two consecutive efforts.b. Determine if cold combinations can combine.c. To determine if the use of menthol can allow optimization of the protocols of cooling.The main results of this thesis highlight that the use of cooling is effective but this efficiency depends on the protocol used. We havehighlighted (1) That in pre-cooling it is necessary to start 1 hour before the effort to have an efficiency of the method;(2) Immersion with menthol is more effective only a single immersion between two efforts of 20 'but that used on clothes its effectiveness is not proven; (3) That wearing a cold vest combined with ingestion from a cold drink to warm up is no more effective than an internal cooling only (4) That menthol can influence performance by playing a role on the CNS. The action of menthol will allow the CNS to perceive the environment as being "More favorable" and therefore result in a change in the feedback thermoregulatory, allow higher performance. This without the menthol isplayed a deleterious role to thermoregulation.

No description available.

Dengue is a major public health problem that affects tens of millions of people annually in tropical and sub-tropical countries. This acute viral infection happens to be severe and even life threatening but there is still no available drug or vaccine. Previous studies have noted early higher viral burden in patients who develop more severe symptoms suggesting that administration of a potent and safe antiviral may prevent progression to severe dengue. To verify this hypothesis, we have conducted the first RCT directed towards reducing the viral burden in vivo by administrating chloroquine (CQ), a cheap and well-tolerated drug that inhibits DENV in vitro with concentrations achievable in vivo, to 307 Vietnamese adults with suspected dengue (257 of them were laboratory-confirmed cases). Unfortunately, we did not see an effect of CQ on the duration of infection. However in patients treated with CQ, we observed a trend towards a lower incidence of severe forms. We did not find any differences in the immune response that can explain this trend. We also found more adverse events, primarily vomiting, with CQ. In addition, we have explored the relationships between clinical features, antibody responses and virological markers in these patients. We found that the early magnitude of viremia is positively associated with disease severity and there are serotype dependent differences in infection kinetics. We found as well that DENV was cleared faster and earlier in patients with secondary infections. To complete this study, we have also evaluated 2 rapid lateral flow tests for the diagnosis of dengue in a panel of plasma samples from 245 RT-PCR confirmed dengue patients and 47 with other febrile illnesses. Our data suggest that the NS1 test component of these tests are highly specific and have similar levels of sensitivity (~60%). Both NS1 assays were significantly more sensitive for primary than secondary dengue. The IgM parameter in the SD Duo test improved overall test sensitivity without compromising specificity. All these findings are of major importance for further anti-viral drug testing.

Alguns estudos mostraram que heterópteros aquáticos podem influenciar a estrutura de comunidades zooplanctônicas. No entanto, parte destes estudos foram realizados em experimentos de laboratório que não são capazes de simular totalmente a estrutura do ecossistema. Para confrontar este problema, técnicas moleculares juntamente com experimentos in situ podem ser adotados. A técnica molecular baseia-se na detecção de DNA das presas (biomarcadores) no tubo digestório dos predadores. O objetivo deste trabalho foi analisar o conteúdo estomacal dos heterópteros Martarega uruguayensis e Rheumatobates crassifemur visando avaliar a hipótese da presença de presas zooplanctônicas por meio de vestígios de DNA , bem como avaliar a existência do efeito da predação dos notonectídeos sobre a densidade populacional das presas no ambiente. Para atender aos objetivos propostos, o trabalho foi dividido em 3 capítulos: O capítulo I descreve como foram escolhidos os biomarcadores moleculares das presas e o desenvolvimento dos primers necessários para conduzir as análises. Os primers específicos são de regiões internas do gene COI das presas zooplanctônicas. Foram testadas suas especificidades e sensibilidade por meio de reações de PCR. Em testes de especificidade, todos os primers amplificaram com êxito o biomarcador das presas-alvo, sendo incapazes de amplificar o biomarcador de qualquer outra espécie testada. Em testes de sensibilidade, os primers amplificaram com sucesso os biomarcadores das presas zooplanctônicas mesmo em baixas concentrações de DNA, assim como diretamente do trato digestório dos predadores; O capítulo II aborda aspectos da dieta dos predadores a partir da frequência de biomarcadores das presas encontrados nos tubos digestório dos insetos coletados no lago. Por meio de 48 reações de PCR com os primers específicos das presas-alvo foram analisados 240 tubos digestórios dos predadores. As presas com maior eletividade foram S. serrulatus e D. gessneri, e a menor foi D. cf. brevireme, apesar da alta abundância no ambiente. Tanto para gerrídeos quanto para notonectídeos há uma seletividade acentuada por espécies de presas de maior tamanho, mesmo que em menor frequência relativa no ambiente quando comparadas a outras espécies. Acredita-se que a preferência por presas maiores esteja relacionada à maior facilidade para detecção e manipulação do predador. A frequências de biomarcadores nos tubos digestórios de M. uruguayensis foi maior no período com maior disponibilidade de presas; O capítulo III avaliou, o efeito do predador M. uruguayensis (Notonectidae) sobre as densidades das populações de presas zooplanctônicas a partir de experimento em mesocosmo. No geral, não houve influência significativa dos predadores sobre nenhuma espécie nos dois primeiros dias. O efeito da predação sobre copepoditos e náuplios foi mais acentuados entre os dias 3 e 4, enquanto que para copépodos adultos foi nos dias 2 e 3. Já para os cladóceros o efeito foi mais acentuado nos dias 4 a 6, exceto para D. cf. brevireme que não teve efeito da predação em nenhum dia. Aspectos relacionados ao tamanho corporal, densidade populacional das presas, capacidade de evasão e diminuição da sobreposição entre predador e presa são fatores fundamentas no padrão de seletividade e da preferência alimentar de notonectídeos. / A few studies have shown that aquatic heteroptera can influence the structure of zooplanktonic communities. However, some of these studies have been conducted in laboratory experiments that are not able to fully simulate the structure of the ecosystem. To confront this problem, a molecular approach along with in situ experiment can be adopted. Molecular approach is based on the detection of prey DNA (biomarkers) in the digestive tract of predators. The objective of this work was to analyze the gut contents of the heteropterans Martarega uruguayensis and Rheumatobates crassifemur to test the hypothesis that will be found traces of zooplankton prey DNA, as well as the effect of the notonectid predation on population density of prey in the environment. To meet the proposed objectives, the work was divided in 3 chapters: Chapter I describes how the molecular biomarkers of prey were chosen and the development of the primers needed to conduct the analyses. The specific primers are from internal regions of the COI gene of zooplanktonic prey. Their specificities and sensibility were tested by means of PCR reactions. In specificity tests, all primers successfully amplified the target prey biomarker and were unable to amplify biomarker of any other species tested. In sensitivity tests, the primers successfully amplified the biomarkers of zooplankton prey even at low DNA concentrations, as well as directly from the digestive tract of predators; Chapter II addresses aspects of the predators diet using the frequency of biomarkers of prey found in the digestive tubes of the insects. By means of 48 PCR reactions, with the specific primers from target prey, were analyzed 240 digestive tracts of predators. The prey with greater electivity were S. serrulatus and D. gessneri, and the smaller one was D. cf. brevireme, despite the high abundance in the environment. For both gerrids and notonectids, there was a marked selectivity for larger size prey, even though at a lower relative frequency in the environment when compared to other species. This suggests that the preference for larger prey is related to the greater facility for detection and manipulation by the predator. The frequencies of biomarkers in the digestive tracts of M. uruguayensis were higher in the period with higher prey availability; Chapter III evaluated the effect of the predator M. uruguayensis on the densities of zooplankton prey populations from experiment in mesocosm. In general, there was no significant influence of predators on any species in the first two days. The effect of predation on copepodites and nauplii were more pronounced between days 3 and 4, whereas for adult copepods on days 2 and 3. The effect on cladocerans was more pronounced on days 4 to 6, except for D. cf. brevireme that was not preyed on. Aspects related to body size, population density of the prey, evasion capacity and decrease overlap between predator and prey are fundamental in the pattern of selectivity and feeding preference of notonectids.

Depuis plus de 150 l’exploitation aurifère en Guyane française bouleverse le paysage en entrainant une déforestation massive des concessions minières. Les conséquences sont multiples, aussi bien pour l’environnement que pour la santé humaine. Pendant des décennies l’utilisation du mercure dans le processus d’extraction a entrainé une contamination du réseau hydrique et de la chaine trophique. Afin d’inscrire l’exploitation aurifère dans une optique de développement durable le code minier impose depuis 1998 une obligation de réhabilitation des sites exploités. Des méthodes de revégétalisation utilisant différentes essences végétales ont donc été adoptées afin d’accélérer les successions écologiques. Le contrôle de la qualité de restauration écologique est néanmoins difficile à mettre en œuvre et il est nécessaire d’avoir des outils de bio-géo-indications fiables et peu couteux pour estimer le recouvrement des fonctionnalités des écosystèmes et apprécier le risque de mobilités des éléments traces toxiques. Dans ce contexte, les objectifs de ce travail de thèse ont été d’évaluer la qualité de restauration écologique de sites miniers en Guyane française à travers une caractérisation des activités microbiennes, du fonctionnement des cycles biogéochimiques d’éléments majeurs (C,N,P) et de la dynamique du mercure. L’originalité de ce travail réside dans l’évaluation dans le temps et dans l’espace des interactions entre couvert végétal – propriétés physico-chimiques du sol – activités microbiennes – spéciation du mercure après revégétalisation et en faire un outils diagnostic de la réussite de cette restauration. Dans ce but, plusieurs campagnes d’échantillonnages ont été réalisées en Guyane sur un panel de sites miniers réhabilités, avec différents types de couverts végétaux. Des échantillons de sols ont été prélevés sur des sites revégétalisés avec des espèces de fabacées, et sur des sites non revégétalisés. Nous avons évalué les fonctionnalités des communautés microbiennes de ces sites avec plusieurs bio-marqueurs de la qualité du sol. Afin d’estimer le devenir du mercure, des mesures du mercure total ainsi que des spéciations opérationnelles et environnementales ont été réalisées. Ce travail de thèse a permis de mettre en évidence un effet positif de la revégétalisation sur la densité et les activités des communautés microbiennes telluriques. Les sites restaurés ont montré une biomasse microbienne, des taux de minéralisation des macroéléments (C,N,P), une diversité catabolique plus élevées que des sites non restaurés. Nos résultats confirment également que la restauration influence les activités des communautés microbiennes anaérobies. En effet, les travaux portant sur les communautés bactériennes ferri-réductrices (BFR) et sulfato-réductrices (BSR) montrent des activités variantes entre les modalités de revégétalisation. Ces différences sont à mettre en relation avec les propriétés physiques et chimiques du sol ainsi qu’avec la nature et la densité du couvert végétal. Les communautés BFR sont actives sur les sites réhabilités alors que les communautés BSR seraient davantage actives sur les sites faiblement restaurés. Ces différences ont des conséquences sur la mobilité du mercure. Nos travaux montrent également que si dans les sites revégétalisés le mercure est associé à des phases stables du sol alors que dans les sites non restaurés il est sous des formes solubles mobilisable dans le réseau hydrique, biodisponible pour les organismes de la chaine trophique. Pour conclure, l’approche interdisciplinaire proposée dans ce travail a permis d’identifier certains processus d’écologie microbienne fondamentaux impactant le recouvrement des fonctionnalités des écosystèmes miniers dégradés. Ce travail offre un outil d’évaluation de la qualité de la restauration écologique original, appliqué et prometteur, qui pourra intéresser les décisionnaires responsables de la réhabilitation des sites miniers en Guyane française / For more than 150 years, gold mining in French Guiana has disrupted the landscape by causing massive deforestation of mining concessions. The consequences are multiple, both for the environment and human health. Indeed, for decades the use of mercury in the extraction process has led to pollution of aquatic systems, contaminating the food chain. In order to ensure that gold mining is carried out in a sustainable development perspective, the Mining Code has imposed an obligation since 1998 to rehabilitate the sites operated. Several revegetation methods using different plant species have been adopted to accelerate ecological succession. However, quality control of ecological restoration is difficult to implement and it is necessary to have reliable and inexpensive bio-geo-indication tools to estimate the recovery of the functionalities of anthropized ecosystems and assess the risk of mobility of toxic metallic elements.In this context, the objectives of this thesis work were to evaluate the quality of ecological restoration of mining sites in French Guiana through a characterization of microbial activities, the functioning of biogeochemical cycles of major elements (C,N,P) and the dynamics of mercury. The originality of this work lies in the evaluation over time and space of the interactions between vegetation cover - physico-chemical properties of the soil - microbial activities - mercury speciation after revegetation and making it a diagnostic tool for the success of this restoration. To this end, several sampling campaigns were carried out in French Guiana on a panel of rehabilitated mining sites, with different types of vegetation cover. Soil samples were taken from replanted sites with fabaceous species (A. mangium and C. racemosa), and from non-restored sites. We then evaluated the main functionalities of the microbial communities of these sites through the use of several soil quality bio-markers. In order to estimate the fate of mercury, measurements of total mercury as well as operational and environmental specimens were carried out. This thesis work revealed a positive effect of revegetation on the density and activities of soil microbial communities. Sites restored with fabaceous species have thus shown microbial biomass, macro-element mineralization rates (C,N,P), and catabolic diversity significantly higher than sites that have not been restored. The associations of fabaceous plants show more conclusive results than the use of monoculture in terms of microbial functionalities. While the activities of aerobic microorganisms have been impacted by the return of vegetation, our results confirm that restoration influences the activities of anaerobic microbial communities. Indeed, work on iron-reducing (IRB) and sulfate-reducing (SRB) bacterial communities shows varying activities between revegetation modalities. These differences are related to the physical and chemical properties of the soil and the nature and density of the vegetation cover. BFR communities are more active on rehabilitated sites while SRB communities are more active on poorly restored sites. These differences in activities have consequences on mercury mobility and methylation. Our work also shows that while mercury in re-vegetated sites is associated with stable phases of the soil, including iron oxides, in non-restored sites it is in soluble forms that can potentially be mobilized in the water network, bioavailable and assimilated by organisms in the food chain.In conclusion, the interdisciplinary approach proposed in this work made it possible to identify certain fundamental microbial ecological processes that impact the recovery of the functionalities of degraded mining ecosystems. This work provides an original, applied and promising tool for assessing the quality of ecological restoration that may be of interest to decision-makers responsible for the rehabilitation of mining sites in French Guiana