Made available in DSpace on 2016-12-23T13:47:35Z (GMT). No. of bitstreams: 1 Rafael Almeida Magris.pdf: 1237040 bytes, checksum: 07bea7179db169152f53f5f9f64662ff (MD5) Previous issue date: 2008-03-24 / A variabilidade interanual, sazonal e entre as fases da maré da comunidade de Copepoda no estuário do rio Mucuri (Bahia, Brasil) foi estudada. Foram coletadas amostras de plâncton em cada estação do ano por um período de cinco anos (2002-2006) em três pontos de amostragem; sendo que em um deles, as amostragens aconteceram de acordo com o ciclo de marés (duas na enchente e duas na vazante). Dados de temperatura, salinidade, pluviosidade e vazão do rio foram obtidos. O inverno e o verão se destacaram por representarem o período seco e o chuvoso, respectivamente. A representatividade de Copepoda na comunidade zooplanctônica variou entre 40 e 63% da abundância total de espécies, e foi composta por 46 taxa, sendo dominada por espécies comuns nos ecossistemas estuarinos (Temora turbinata, Parvocalanus crassirostris, Acartia lilljeborgi, Oithona hebes, dentre outras). Foram encontrados indivíduos em todos os estágios do ciclo de vida, exemplificando o papel do estuário na reprodução e crescimento das espécies. Para espécies estenohalinas (e.g. Notodiaptomus sp. e Thermocyclops minutus), as variações interanuais e sazonais parecem ser mais importantes enquanto as espécies eurihalinas (a maioria das espécies dominantes) tiveram suas densidades controladas pela variabilidade entre as fases de maré. / Copepod community variability among years, seasons and tidal fluctuations at the Mucuri River estuary (Bahia, Brasil) were studied. Zooplankton samples were collected in each season for a period of five years (2002-2006) at three sampling stations; with one of the stations sampled at each tidal cycle (two neap and two flood tides). Temperature, salinity, river flow and rainfall data were obtained. Winter and summer represented the dry and wet seasons, respectively. Copepods abundance ranged from 40 to 63% of the total zooplankton community and was composed of 46 taxa, dominated by common estuarine species such as Temora turbinata, Parvocalanus crassirostris, Acartia lilljeborgi, Oithona hebes, among others). Individuals in all of the life stages were found, exemplifying the role of the estuary in the reproduction and growth of several species. For the stenohaline species (e.g. Notodiaptomus sp. and Thermocyclops minutus), interannual and seasonal variations seems to be more important while for the euryhaline species (the majority of the dominant ones) had their densities controlled by tidal variability.

Les réglementations conduisent à multiplier les évaluations du risque écologique lié au rejet des substances chimiques dans les milieux aquatiques avec pour objectif de protéger les populations naturelles. Cependant, ce niveau de protection visé ne peut être utilisé facilement pour établir un lien direct entre une contamination et ses effets. Pour palier cette difficulté, les approches multi-échelles basées sur l'étude des effets des contaminations sur des marqueurs individuels puis sur l'extrapolation de ces effets au niveau des poipulations à partir de modèles de dynamique de population représentent des démarches prometteuses et commencent à être bien acceptées dans les démarches prédictives.Cependant, leur utilisation pour le diagnostic de la qualité des milieux aquatiques reste pour le moment très rare, d'une part en raison de la forte variabilité des réponses des marqueurs individuels in situ liée à l'influence de divers facteurs environnementaux confondants pour l'évaluation de la toxicité, et d'autre part à cause du manque de pertinence environnementale des modèles actuellement proposés. Centré sur l'utilisation de deux espèces couramment observées dans les cours d'eau européens et présentant des caractéristiques écologiques et phylogéniques contrastées : le crustacé Gammarus fossarum et le mollusque Potamopyrgus antipodarum, ce travail doctoral a permis : 1- de proposer une méthodologie pour prendre en compte l'influence des facteurs de confusion dans le but d'améliorer la lecture des bioessais in situ basés sur la mesure des marqueurs individuels sur des organismes encagés et 2- de développer des modèles de dynamique de population écologiquemnt pertinents. / The regulatory framework lead to increase the assessments of the ecological risk linked to the dischaarge of chemical substances in aquatic environment with the aim to protect natural populations. However, this target level of protection cannot be used so easily to etablish a direcet link between a contamination and its effects. In order to overcome this difficulty, the multi-scale approaches based on the study of the effects of the contaminations on individual markers and then on the extrapolation of these effects at the population level with population dynamic models reprensent promising tools and start to bewell accepted in predictive processes. Yet, their use for the diagnosis of water quality remainsrare for the moment, on the one hand, because of the important varaibility of answers of individual makers in situ linked to the influence of diverse confounding environmental factors for the assessments of toxicity and, on the other hand, because pf the lack of environmental relevance of models currently proposed. Focused on the use of 2 species widely observed in European rivers and presenting contrastingecological and phylogenetic characteristics : the Grammar fossarum crutacean and the Potamopyrgus antipodarum mollusc, this doctoral degree first propose a methodology to consider the influenceof confounding factors in order to improve the reading of biological in situ tests based on the measurment of individual markers on caged organisms and second, to develop ecologically relevant population models. Thus, this work allowed to underline the importance of the consideration of confounding factors (i.e. temperature), in different in situ tests based on the measurment of individul markers on caged organisms. Moreover, population models for both species have been defined in order to test the influence of life histories and seasonal variations on demographic sensitivity of populations.

The stem bark of the protected tree species, Curtisia dentata (Burm. f.)C.A.Sm., is one of the most popular plant species harvested and traded at traditional medicine markets in South Africa. The overexploitation of C. dentata trees lead to a “Near Threatened” conservation status and the population trend is portrayed as “declining”. In the KwaZulu-Natal Province of South Africa, C. dentata is completely conservation dependent. This study is not based on drug discovery or toxicological studies, but on the concern that the stem bark of C. dentata trees are harvested, prepared into remedies and consumed as traditional medicine without knowledge regarding the chemical compounds in the stem bark, particularly since the chemical composition of C. dentata stem bark was unknown to date. Phytochemical analyses were firstly conducted to determine the chemical composition of C. dentata stem bark using various solvents and various analytical methods, and secondly, to determine how seasons and regional separation of C. dentata trees affect the chemical profiles of C. dentata stem bark from an environmental and nature conservation perspective. Plants are known to contain numerous chemical compounds. Compounds isolated from a particular plant species are therefore not the only compounds present in that species, and although a plant has proven pharmacological properties, they can still cause harm. Previous studies on C. dentata aimed at validating the plant species as a medicinal plant by examining extracts of the leaves, twigs and stem bark’s potentials against known pathogens and selected cancer cells in vitro and in vivo, and its anti-inflammatory, antioxidant and antiverotoxic properties. Four pentacyclic triterpenoids and one steroidal compound were also previously isolated from C. dentata leaves, however, the leaves are not used in traditional medicines, but were suggested as alternative for stem bark as the harvesting of leaves is less destructive. The efficacy of these compounds as therapeutic agents is, however, compromised by their low solubility in water and thus their potential to penetrate permeating biological membranes. Moreover, in vitro toxicity studies distort the picture of its actual potentials on human health as the whole human metabolome and all its processes, including uptake and phase I and phase II biotransformation are not included. In vivo toxicity studies on mammalian animal species may also not present a true picture of a chemical or extract’s toxic effects on humans as animal metabolisms differ from those of humans. The chemical composition of leaves and stem bark may furthermore also be in contrast to some extent, and therefore chemical compounds were also isolated from C. dentata stem bark in this study. Scientific studies on plant-based medicines generally involve the discovery or identification of compounds that may be beneficial, and which can be exploited in future. Chemical compounds in traditional medicines or other plant-based health products which may cause adverse effects are generally ignored. Moreover, scientific studies that consider that some compounds present in plant extracts may derive from contaminants are equally limited. Traditional plant-based medicines are neither standardized nor regulated in South Africa. Users of traditional plant-based traditional medicines therefore consume uncertain dosages of both beneficial and hazardous substances, as well as contaminants simultaneously. Certain chemical compounds are carcinogens or mutagens or have the ability to accumulate in human tissues. Adverse effects may therefore only manifest after several years of use and will subsequently not be connected to the use of a particular traditional plant-based medicine. The goal of the thesis is therefore to provide a holistic portrayal of the full spectrum of chemical compounds in extracts of C. dentata stem bark and to discuss, where literature is available, the effect(s) each chemical compound may have on human health. Moreover, this thesis investigates variations in chemical composition and concentration in individual trees, seasonal variations and variations in composition and concentrations in the stem bark of C. dentata trees from geographically distinct regions. Most unexpected was that not all C. dentata stem bark samples contained chemical compounds with known beneficial potentials at each sampling date, and that chemical compounds may be region-specific and also tree-specific, which confirms that plants produce secondary metabolites according to the needs of each individual plant. Additional insight into the chemical composition and concentration of C. dentata trees is provided by the distribution profiles of amino acids in C. dentata stem bark. Extreme variations within populations and between geographical areas support the need for the cultivation of C. dentata trees to ensure sustainable production of homogenous material for chemical homogeneity. / Environment Science / PhD. (Environment Science)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Lippia alba (Mill.) N. E. Brown is a native medicinal plant of South America. Known popularly as false-melissa , its leaves and roots are used in the treatment of some illnesses, including some of infective etiology. The presence of essential oils, among other metabolites with recognized antimicrobial activity, can explain its medicinal use. This paper describes the chemical analyses and antimicrobial activity of the essential oils from Lippia alba at different seasons of the year, as well as the bio-guided fractionation, the isolation and the structure elucidation of its main constituents. Lippia alba was cultivated in São Luiz Gonzaga, RS, Brazil, and its leaves were collected in 2005 and 2006 in the middle period (January, April, July and October) of each season. A voucher specimen (SMDB n° 10.050) was deposited in the herbarium of the Department of Biology, UFSM. The extraction of the essential oils was performed by the hydrodistillation method of fresh leaves. The oils were analyzed by GC-MS and their constituents were identified by the comparison of Kovat s retention indexes and mass spectra with literature data. The essential oil was fractionated by CC over silica gel for the isolation of germacrene D-4-ol and linalool, both identified by GC-MS, 13C and 1H NMR, DEPT-135, COSY and HETCOR. The antimicrobial activity of the essential oils, fractions and isolated compounds were determined by the broth microdilution method. The essential oil showed qualitative and semi-quantitative variability in relation to the seasons of the year. The yield ranged from 0.3 to 0.6%, being lower in winter and higher in summer, autumn and spring. The essential oil was composed of monoterpenoids (69 - 84%) and sesquiterpenoids (6 - 24%), being most of them oxygenated and hidrocarbonated, respectively. Moreover, the major compounds (> 15%) were not the same between the years of the analysis. The seasonal variability influenced the antimicrobial activity of the essential oils. With the exception of P. aeruginosa, all other microorganisms were susceptible to the essential oil. The most sensitive ones were S. cerevisiae (MIC and MFC of 800 μg/mL for the oil obtained in January), S. aureus (MIC of 800 μg/mL and MBC of 1600 μg/mL for the oils obtained in April and July) and K. pneumoniae (MIC and MFC of 1600 μg/mL for the oil extracted in July). In view of the antimicrobial activity, winter and summer are the best seasons for the collection and extraction of essential oils. The bio-guided fractionation of the essential oil showed that the fractions containing greater amounts of oxygenates are more active than those containing hydrocarbon compounds. Germacrene D-4-ol presented activity against S. cerevisiae (MIC and MFC of 200 μg/mL), P. zopfii (MIC and MFC of 400 μg/mL) and S. aureus (MIC and MBC of 800 μg/mL), while linalool was inactive against the tested microorganisms up to 3200 mg/mL. / Lippia alba (Mill.) N. E. Brown é uma planta medicinal nativa da América do Sul. Conhecida popularmente como falsa-melissa , suas folhas e raízes são empregadas no tratamento de várias doenças, incluindo algumas de etiologia infecciosa. A presença dos óleos essenciais, entre outros metabólitos com reconhecida atividade antimicrobiana, pode explicar o seu uso como medicinal. Este trabalho descreve a analise química e a atividade antimicrobiana dos óleos essenciais de Lippia alba nas diferentes estações do ano, bem como o fracionamento bio-guiado, o isolamento e a elucidação estrutural dos seus principais constituintes. Lippia alba foi cultivada no município de São Luiz Gonzaga, RS, Brasil, e suas partes aéreas foram coletadas no período médio de cada estação (janeiro, abril, julho e outubro) durante o ano de 2005 e 2006. Material testemunha (SMDB n° 10.050) encontra-se depositado no Herbário do Departamento de Biologia da UFSM. Para a realização dos experimentos, foram utilizadas as folhas frescas. A extração dos óleos essenciais foi realizada pelo método da hidrodestilação. Os óleos foram analisados por CG-EM e seus constituintes identificados pela comparação dos índices de retenção de Kovats e espectros de massas com dados da literatura. O óleo essencial também foi fracionado por CC sobre gel de sílica até o isolamento do germacreno D-4- ol e do linalol, ambos identificados por CG-EM, RMN 13C e 1H, DEPT-135, COSY e HETCOR. A atividade antimicrobiana dos óleos essenciais, das frações e das substâncias isoladas foi determinada pelo método de microdiluição em caldo. O óleo essencial apresentou variabilidade qualitativa e semiquantitativa em relação às estações do ano. O rendimento variou na ordem de 0,3 a 0,6%, sendo menor no inverno, e maior no verão, outono e primavera. O óleo essencial foi composto de monoterpenóides (69 - 84%) e sesquiterpenóides (6 24%), sendo a maioria deles oxigenados e hidrocarbonados, respectivamente. Os compostos majoritários (>15%) não foram os mesmos entre os diferentes anos de análise. A variabilidade sazonal, por sua vez, influenciou a atividade antimicrobiana dos óleos essenciais. Com exceção de P. aeruginosa, todos os outros microorganismos foram sensíveis ao óleo essencial de pelo menos uma estação. Os microorganismos com menor CIM foram S. cerevisiae (CIM e CFM de 800 μg/mL para o óleo obtido em janeiro), S. aureus (CIM de 800 μg/mL e CBM 1600 μg/mL para os óleos obtidos em abril e julho) e K. pneumoniae (CIM e CBM de 1600 μg/mL para o óleo extraído em julho). Tendo em vista a atividade antimicrobiana, o inverno e o verão constituem as melhores épocas para a coleta e extração dos óleos essenciais. O fracionamento bio-guiado do óleo essencial mostrou que frações contendo maiores quantidades de compostos oxigenados são mais ativas do que aquelas contendo compostos hidrocarbonados. Germacreno D-4-ol apresentou atividade contra S. cerevisiae (CIM e CFM de 200 μg/mL), P. zopfii (CIM e CFM de 400 μg/mL) e S. aureus (CIM e CBM de 800 μg/mL), ao passo que linalol foi inativo contra os microorganismos testados até a concentração de 3200 mg/mL.