by Chan Hiu-wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 123-133). / Text in English; abstracts in English and Chinese. / by Chan Hiu-wai. / Acknowledgements --- p.i / Abstract --- p.ii / List of Figures --- p.x / List of Tables --- p.xiii / List of Abbreviations --- p.xv / Page / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The chemical class: Phthalate esters --- p.1 / Chapter 1.2 --- Di(2-ethylhexyl)phthalate --- p.2 / Chapter 1.2.1 --- Characteristics of DEHP --- p.5 / Chapter 1.2.2 --- Production and applications --- p.5 / Chapter 1.2.3 --- Environmental releases and environmental fate --- p.8 / Chapter 1.2.4 --- Toxicity of DEHP --- p.8 / Chapter 1.2.4.1 --- Mammalian toxicity --- p.9 / Chapter 1.2.4.2 --- Toxicity to aquatic organisms --- p.10 / Chapter 1.2.5 --- Regulations --- p.10 / Chapter 1.3 --- Conventional technologies for DEHP removal --- p.11 / Chapter 1.3.1 --- Biodegradation --- p.11 / Chapter 1.3.2 --- Coagulation --- p.11 / Chapter 1.3.3 --- Adsorption --- p.11 / Chapter 1.4 --- Innovative technologies for DEHP removal --- p.12 / Chapter 1.4.1 --- Biosorption --- p.13 / Chapter 1.4.1.1 --- Definition of biosorption --- p.13 / Chapter 1.4.1.2 --- Mechanisms --- p.13 / Chapter 1.4.1.3 --- Selection of biosorbents --- p.17 / Chapter 1.4.1.4 --- Assessment of biosorption performance --- p.21 / Chapter a. --- Batch adsorption experiments --- p.21 / Chapter b. --- Modeling of biosorption --- p.21 / Chapter 1.4.1.5 --- Recovery of biosorbents --- p.23 / Chapter 1.4.1.6 --- Development of biosorption process --- p.23 / Chapter 1.4.1.7 --- Seaweeds as biosorbents --- p.24 / Chapter 1.4.2 --- Advanced oxidation processes --- p.27 / Chapter 1.4.3 --- Heterogeneous photocatalytic oxidation --- p.30 / Chapter 1.4.3.1 --- Photocatalyst --- p.30 / Chapter 1.4.3.2 --- General mechanisms --- p.31 / Chapter 1.4.3.3 --- Influencing parameters in PCO --- p.33 / Chapter 1.4.3.4 --- Enhanced performance by addition of hydrogen peroxide --- p.33 / Chapter 2 --- Objectives --- p.36 / Chapter 3 --- Materials and Methods --- p.38 / Chapter 3.1 --- Chemical reagents --- p.38 / Chapter 3.2 --- Biosorption of DEHP by seaweed biomass --- p.39 / Chapter 3.2.1 --- Biosorbents --- p.39 / Chapter 3.2.2 --- Determination method of DEHP --- p.39 / Chapter 3.2.3 --- Batch adsorption experiments --- p.44 / Chapter 3.2.3.1 --- Screening of potential biomass --- p.44 / Chapter 3.2.3.2 --- Characterization of beached seaweed and S. siliquastrum --- p.44 / Chapter a. --- Total organic carbon (TOC) content --- p.44 / Chapter b. --- Leaching of biomass components --- p.45 / Chapter 3.2.3.3 --- Combined effect of pH and biomass concentration --- p.45 / Chapter 3.2.3.4 --- Effect of retention time --- p.45 / Chapter 3.2.3.5 --- Effect of agitation rate --- p.45 / Chapter 3.2.3.6 --- Effect of temperature --- p.46 / Chapter 3.2.3.7 --- Effect of particle size --- p.46 / Chapter 3.2.3.8 --- Effect of DEHP concentration --- p.46 / Chapter 3.2.4 --- Recovery of adsorbed DEHP from seaweed biomass --- p.47 / Chapter 3.2.4.1 --- Screening for suitable desorbing agents --- p.47 / Chapter 3.2.4.2 --- Multiple adsorption-desorption cycles --- p.47 / Chapter 3.2.5 --- Statistical analysis --- p.43 / Chapter 3.3 --- Photocatalytic oxidation --- p.48 / Chapter 3.3.1 --- Photocatalytic reactor --- p.48 / Chapter 3.3.2 --- Optimization of reaction conditions --- p.48 / Chapter 3.3.2.1 --- Effect of reaction time --- p.48 / Chapter 3.3.2.2 --- Effect of initial pH --- p.51 / Chapter 3.3.2.3 --- Effect of Ti02 concentration --- p.51 / Chapter 3.3.2.4 --- Effect of UV intensity --- p.52 / Chapter 3.3.2.5 --- Effect of H202 concentration --- p.52 / Chapter 3.3.2.6 --- Effect of initial DEHP concentration and irradiation time --- p.52 / Chapter 3.3.2.7 --- Statistical analysis --- p.52 / Chapter 3.3.4 --- Determination of mineralization of DEHP by analyzing total Organic carbon (TOC) content --- p.53 / Chapter 3.3.5 --- Identification of intermediate products of DEHP --- p.53 / Chapter 3.3.6 --- Evaluation for the toxicity of DEHP and intermediate products --- p.53 / Chapter 3.3.6.1 --- Microtox® test --- p.53 / Chapter 3.3.6.2 --- Amphipod survival test --- p.55 / Chapter 3.4 --- Feasibility of combining biosorption and photocatalyic oxidation as an Integrated treatment for DEHP --- p.57 / Chapter 3.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.57 / Chapter 3.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.57 / Chapter 4 --- Results --- p.58 / Chapter 4.1 --- Determination method of DEHP --- p.58 / Chapter 4.2 --- Biosorption --- p.58 / Chapter 4.2.1 --- Batch adsorption experiments --- p.58 / Chapter 4.2.1.1 --- Screening of potential biomass --- p.58 / Chapter 4.2.1.2 --- Characterization of beached seaweed and S. siliquastrum --- p.61 / Chapter a. --- Total organic carbon (TOC) content --- p.61 / Chapter b. --- Leaching properties --- p.61 / Chapter 4.2.1.3 --- Combined effect of pH and biomass concentration --- p.61 / Chapter 4.2.1.4 --- Effect of retention time --- p.74 / Chapter 4.2.1.5 --- Effect of agitation rate --- p.74 / Chapter 4.2.1.6 --- Effect of temperature --- p.74 / Chapter 4.2.1.7 --- Effect of particle size --- p.74 / Chapter 4.2.1.8 --- Effect of initial DEHP concentration: Modeling by Langmuir and Freundlich adsorptin isotherm --- p.79 / Chapter 4.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.84 / Chapter 4.2.2.1 --- Screening for suitable desorbing agents --- p.84 / Chapter 4.2.2.2 --- Multiple adsorption-desorption cycles --- p.84 / Chapter 4.3 --- Photocatalytic oxidation --- p.90 / Chapter 4.3.1 --- Optimization of reaction conditions --- p.90 / Chapter 4.3.1.1 --- Effect of reaction time --- p.90 / Chapter 4.3.1.2 --- Effect of initial pH --- p.90 / Chapter 4.3.1.3 --- Effect of TiO2 concentration --- p.90 / Chapter 4.3.1.4 --- Effect of UV intensity --- p.90 / Chapter 4.3.1.5 --- Effect of H2O2 concentration --- p.95 / Chapter 4.3.1.6 --- Effect of initial DEHP and irradiation time --- p.95 / Chapter 4.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.95 / Chapter 4.3.3 --- Identification of intermediate products of DEHP --- p.95 / Chapter 4.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.102 / Chapter 4.3.4.1 --- Microtox® test --- p.102 / Chapter 4.3.4.2 --- Amphipod survival test --- p.102 / Chapter 4.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.102 / Chapter 4.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.102 / Chapter 4.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.103 / Chapter 5 --- Discussion --- p.108 / Chapter 5.1 --- Determination method of DEHP --- p.108 / Chapter 5.2 --- Biosorption --- p.108 / Chapter 5.2.1 --- Batch adsorption experiments --- p.108 / Chapter 5.2.1.1 --- Screening of potential biomass --- p.108 / Chapter 5.2.1.2 --- Characteristic of S. siliquastrum and beached seaweed --- p.109 / Chapter 5.2.1.3 --- Combined effect of pH and biomass concentration --- p.109 / Chapter 5.2.1.4 --- Effect of retention time --- p.111 / Chapter 5.2.1.5 --- Effect of agitation rate --- p.111 / Chapter 5.2.1.6 --- Effect of temperature --- p.111 / Chapter 5.2.1.7 --- Effect of particle size --- p.112 / Chapter 5.2.1.8 --- Effect of initial DEHP concentration: Modeling of Langmuir and Freundlich adsorption isotherms --- p.112 / Chapter 5.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.114 / Chapter 5.2.2.1 --- Screening for suitable desorbing agents --- p.114 / Chapter 5.2.2.2 --- Multiple adsorption-desorption cycles --- p.115 / Chapter 5.3 --- Photocatalytic oxidation --- p.115 / Chapter 5.3.1 --- Optimization of reaction conditions --- p.115 / Chapter 5.3.1.1 --- Effect of reaction time --- p.115 / Chapter 5.3.1.2 --- Effect of pH --- p.116 / Chapter 5.3.1.3 --- Effect of TiO2 concentration --- p.116 / Chapter 5.3.1.4 --- Effect of UV intensity --- p.116 / Chapter 5.3.1.5 --- Effect of H2O2 concentration --- p.117 / Chapter 5.3.1.6 --- Effect of DEHP concentration and irradiation time --- p.117 / Chapter 5.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.117 / Chapter 5.3.3 --- Identification of intermediate products of DEHP --- p.118 / Chapter 5.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.119 / Chapter 5.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.119 / Chapter 6 --- Conclusions --- p.121 / Chapter 7 --- References --- p.123

Les algues del gènere Cystoseira són els principals organismes formadors d'estructura en fons rocosos ben il·luminats del Mar Mediterrani. Formen unes comunitats molt estructurades que s'assemblen ecològicament als boscos terrestres i que són sensibles als impactes antròpics. Aquesta tesi s'ha centrat en l'estudi de les espècies i comunitats dominades per Cystoseira que es troben en ambients calmats, és a dir, en petites cales i/o badies. S'han abordat diversos aspectes com són la distribució, composició, estructura i biogeografia d'aquestes comunitats, així com els efectes de la contaminació sobre les mateixes. Per una banda, s'ha documentat l'estat actual de les comunitats dominades per C. crinita a nombrosos llocs al llarg de tot el Mediterrani, aportant informació sobre la seva composició, estructura, variació biogeogràfica i dinàmica de la comunitat a llarg termini. S'ha documentat la desaparició de diverses espècies de Cystoseira en zones afectades per impactes antròpics diversos i s'ha proporcionat la primera evidència experimental de la desaparició d'espècies de Cystoseira a causa de la contaminació. / Macroalgae of the genus Cystoseira are the main engineering species in shallow rocky bottoms in the Mediterranean Sea. They dominate diverse and structured assemblages which are ecologically similar to terrestrial forests and show high sensitivity to human impacts. This thesis has focused on the study of the species and assemblages dominated by Cystoseira which appear in sheltered environments, such as bays and small coves. The study of the distribution, composition, structure, biogeography, effects of pollution and recovery potential of these assemblages are the main subjects of the thesis. By one hand, the current state of C. crinita-dominated assemblages has been assessed for many localities through the Mediterranean. Information on the composition, structure, biogeography and long-term dynamics of these assemblages has been provided. The disappearance of different Cystoseira species in impacted areas has been documented and the first experimental evidence of pollution negative effects on Cystoseira populations has been provided.

Bibliography: leaves 191-225. / 2 v. : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The temporal dynamics of eight subtidal mixed macroalgal communities were quantified. The results were discussed in terms of the implications for sampling programs in the future and the reliability of previous work. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1997?

Orientador: João Frederico da C. A. Meyer / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-13T10:29:33Z (GMT). No. of bitstreams: 1 Abreu_LucianaCarrara_M.pdf: 4346828 bytes, checksum: 033ab3f8708d62fd87d7a14fc7b8bb11 (MD5) Previous issue date: 2009 / Resumo: Este trabalho se constitui numa ferramenta que possibilita melhor avaliar, através de simulações computacionais, como a poluição pode afetar (ou vir a afetar) populações de macroalgas que interagem, também, entre si num importante ecossistema marinho localizado próximo à região metropolitana do Rio de Janeiro, a baía de Sepetiba. Com base no relato de estudos de campo nesta baía, foram reunidas informações sobre as características das principais macroalgas desta região, bem como sobre a poluição e suas influências sobre a flora marinha local. Neste cenário, foi justificadamente construído um modelo evolutivo formado por equações diferenciais parciais que descrevem a interação entre duas espécies de macroalgas sob a influência de um poluente de superfície, que pode ser tóxico ou servir de alimento às plantas marinhas, variando de uma espécie a outra. Inevitavelmente, participam desta interação as células de reprodução de cada espécie de macroalga e, por isso, estão incluídas no modelo. Estão apresentadas as formulações clássica e variacional de um modelo mais simples, com as posteriores discretizações espaciais, em que foi utilizado o método de Elementos Finitos (aqui com elementos triangulares de primeira ordem), e discretização temporal, com o uso do método de Crank-Nicolson, de segunda ordem de aproximação. As discretizações, no modelo mais complexo, seguem passos totalmente análogos aos do modelo mais simples. É também apresentado um capítulo sobre o cálculo das submatrizes de rigidez, necessário para a implementação. Finalmente são mostrados alguns experimentos computacionais que permitem simular situações hipotéticas de risco, com o objetivo de se obter cenários de impactos causados pela poluição sobre a flora marinha local e, com isso, alertar para os problemas gerados pela intervenção antrópica na região e motivar um planejamento de estratégias e políticas de prevenção e de contingência. / Abstract: This work describes a tool created to enable better evaluations - by the adequate use of computational simulations - of how environmental impact can affect (or come to affect) different populations of macroalgae which interact among themselves in an important marine ecosystem located south of Rio de Janeiro state, that of Sepetiba bay. Based upon previous records of local studies in this area, data was collected highlighting characteristics of these species of macroalgae, as well as that of the effect of pollution upon local marine flora. In this general setting, a model was developed based on a non-linear system of partial differential equations that describes the interaction among two distinct species of algae under the impact of a polluting material, an impact that can either be toxic or a nourishment for one or both of these algae. Population dynamics and movements are included in the model, as well as reproduction cells of these species. Classic and variational formulations are presented, with Ritz-Galerkin discretization for space variables, as well as a Crank-Nicolson method for approximations in time, both methods of second-order. Simpler variations of the model (and of the discretized approximation) are presented in order to gain an insight as regards the algorithmic processes. In the more complex situation, a separate chapter describes the numerical and computational tools necessary in the deffnition of the final schemes. Computationally defined dynamical scenarios are presented, illustrating how risk assessments can be undertaken, simulating the mentioned effects of the presence of polluting materials in the region, creating an important tool for possible effects of the anthropic activities in the region, permitting the planning processes for the establishment of strategies and policies for environmental protection and damage repair. / Mestrado / Mestre em Matemática Aplicada

Sodwana Bay, situated within the iSimangaliso Wetland Park, is ecologically important as it contains high-latitude corals and the most southerly known population of coelacanths. This thesis utilised stable isotope and lipid analyses to investigate the trophic ecology of the area, in particular, understanding the relative contribution of inshore and offshore primary production to consumers inhabiting intertidal and shallow subtidal, coral reef, deep reef, canyon head and pelagic habitats. Seaweeds, excluding certain species of red seaweeds with highly depleted carbon signatures, and phytoplankton, such as diatoms, were found to be the principal sources of primary production for all consumers. Offshore production was typified by dinoflagellates. Particulate organic matter (POM) was spatio-temporally variable. Three distinct productivity periods related to nutrient cycling were noted with enriched carbon signatures and higher organic matter loads associated with warmer water. Inshore primary production was an important source of carbon to consumers in all habitats with the exception of zooplankton that were more reliant on pelagic primary production. Benthic invertebrates reflected a gradient in the utilisation of inshore production, due to the reduced availability of this source further offshore. Consumers at the furthest sites offshore were found to include a substantial quantity of inshore-derived production in their diets. Fishes, which are more mobile, were found to incorporate a similar proportion of inshore production into their diets regardless of where they were collected from.

Este trabalho envolve o estudo sobre os níveis de pigmentos fotossintéticos, carotenóides e clorofilas, presentes nas algas marinhas Tetraselmis gracilis e Gracilaria tenuistipitata, em condições de senescência celular e estresse antropogênico (poluição metálica). Em razão do papel fundamental dos carotenóides na organização de membranas tilacóides, o papel estrutural de carotenos e do extrato metanólico de T. gracilis em bicamadas lipídicas também foi avaliado. Para estes estudos foram realizados o cultivo, coleta e construção das curvas de crescimento das algas, obtenção dos cromatogramas típicos, identificação de alguns pigmentos fotossintéticos através de padrões, análise dos extratos brutos em diferentes fases de crescimento e respectiva quantificação. Foram realizados bioensaios de toxicidade dos metais Cd, Cu, Hg e Pb e foram estimados os parâmetros toxicológicos CE15 e CE50 (concentração efetiva para a redução de 15 e 50%, respectivamente, do crescimento algal). Os modelos de estresse agudo e crônico foram construídos para cada metal e a quantificação dos pigmentos fotossintéticos foi realizada. Lipossomos foram confeccionados com a incorporação de carotenos e do extrato metanólico de T. gracilis na bicamada e foram realizadas medidas de espalhamento de luz, de calorimetria, do diâmetro hidrodinâmico e de fosfolípides. A cinética de liberação e de permeação de NO foi estudada através de medidas de fluorescência e de quimiluminescência. Também foi realizada a extração e pré-isolamento dos carotenóides presentes em T. gracilis. Os mecanismos de defesa contra espécies reativas de oxigênio foram diferentes em razão das distintas variações observadas nos níveis de pigmentos para cada metal estudado e tipo de estresse. Também foi observado um aumento do nível de pigmentos em função do aumento do tempo de exposição correspondendo provavelmente a uma estratégia aclimatativa extremamente importante no papel de adaptação e sobrevivência de organismos fotossintéticos, o que torna este tipo de avaliação, principalmente dos níveis de carotenóides, uma ferramenta útil como parâmetro de avaliação de poluição ambiental, além do emprego da biomassa como ferramenta de biorremoção de metais. Em relação aos valores de CE50 observados, o valor encontrado para o Cu foi inferior ao padrão previsto na Resolução do CONAMA no 357. Portanto, efluentes contendo Cu em níveis permitidos poderão causar danos à biota marinha. Mais ainda, sugere-se que os limites recomendáveis para este metal deverão ser revistos e alterados para a preservação de ecossistemas aquáticos. A incorporação do extrato de T. gracilis ocasionou uma grande perturbação na estruturação da membrana, resultando na fluidificação da bicamada lipídica, independente da fase de crescimento. O β-caroteno e o licopeno interferem na estruturação de bicamadas lipídicas diminuindo o diâmetro hidrodinâmico das vesículas unilamelares grandes, efeito ainda não descrito na literatura, reduzindo o valor da temperatura na qual se inicia a transição de fase, alargando a faixa onde ocorre a transição, reduzindo os valores capacidade calorífica e da entalpia e, conseqüentemente, modificando a cooperatividade da transição. Somente o β-caroteno causou fluidificação do sistema lipídico e aumento da velocidade de permeação de NO através da membrana, sugerindo o provável papel do β-caroteno na modulação de propriedades físicas da membrana. / This work involves the study of the levels of photosynthetic pigments, carotenoids and chlorophylls, contained in the marine algae Tetraselmis gracilis and Gracilaria tenuistipitata, under conditions of cellular senescence and anthropogenic stress (metallic pollution). Due to the fundamental organizational role of carotenoids in thylakoid membranes, its structural features in lipid bilayers were evaluated. Also in this last mentioned study, it was employed the methanolic extract of T. gracilis. In order to perform these studies, the algae were cultivated and the growth curves determined. Also, the typical chromatograms were obtained, and some photosynthetic pigments were identified trough commercial standards, which were then analyzed and quantified in crude extracts of different growth phases. The toxicity of the metals Cd, Cu, Hg and Pb were determined trough bioassays, which led to the toxicological parameters EC15 and EC50 estimation (the effective concentration that causes 15 and 50% of reduction of the algal growth, respectively). For each metal, the acute and chronic stress models were built, and the photosynthetic pigments contents\' quantified. Liposomes were constructed with the incorporation of carotenes and of the T. gracilis\' methanolic extract in the bilayer, which were then submitted to light scattering, calorimetric, hydrodynamic radius and phospholipid assays. Fluorescence and chemiluminescence measurements were used to study the NO kinetics of liberation and permeation. Also, it was accomplished the extraction and pre-isolation of carotenes contained in T. gracilis. For each type of metal and stress occasioned, different levels of pigments were observed, a consequence of the different mechanisms employed against reactive oxygen species. At higher exposure periods, higher pigments\' contents were quantified, which probably corresponds to an algae acclimatative strategy. The EC50 value found for Cu is higher than the standard one previously stated in the CONAMA\'s nº 357 resolution. This means that effluents containing Cu, in levels allowed by the law, may cause damage to the marine biota. Moreover, it\'s suggested a reevaluation of the standard limiting value for this metal, in order to preserve aquatic ecosystems. A higher fluidity of the lipid bilayer, occasioned by a large perturbation of the membrane\'s structure, was accomplished by incorporating the extract of T. gracilis. This was observed independently of the cells\' growth phase. &$946;-carotene and licopene interfere in the lipid bilayer structure, lowering the hydrodynamic diameter of large unilamellar vesicles, an effect not previously reported in literature. This reduces the temperature were the phase transition initiates, broadens the transition gap, lowers the calorific capacity and enthalpy values, consequently, modifying the transition cooperation. Only β-carotene induces a higher fluidity of the lipid system and a faster NO permeation trough the membrane, which suggests that it may modify physical properties of the membrane.

As algas da ordem Halymeniales (Rhodophyta) apresentam grande importância ecológica e econômica como produtores primários e de compostos bioativos, além de incluírem espécies invasoras em várias localidades do mundo. A taxonomia do grupo é bastante problemática, com vários registros de identificações equivocadas e mudanças nomenclaturais. Em virtude disso, diversos estudos têm incluído ferramentas moleculares como auxílio à taxonomia morfológica do grupo. O objetivo deste estudo é investigar por meio de técnicas moleculares e morfológicas a diversidade da ordem Halymeniales no litoral do Brasil de forma, a contribuir para o conhecimento da flora marinha do país. Para isso, foram sequenciados três marcadores moleculares, UPA, COI-5P e rbcL, cujos dados, combinados com a observação de caracteres morfológicos, resultaram na delimitação de 26 espécies. Dessas, 11 são espécies novas para a ciência: Corynomorpha cf. clavata, dois táxons morfologicamente identificados como \"Cryptonemia\" crenulata, dois táxons morfologicamente identificados como Cryptonemia seminervis, Halymenia ignifera, Halymenia pinnatifida, Halymenia silviae, Grateloupia cf. dichotoma, Grateloupia cf. filicina 1 e Grateloupia cf. filicina 2. Pelo menos sete gêneros novos foram encontrados, representados pelos táxons: \"Cryptonemia\" bengryi, integrantes do complexo \"Cryptonemia\" crenulata, \"Cryptonemia\" delicatula, \"Halymenia\" elongata, \"Halymenia\" floridana, Halymeniales sp. 1 e Halymeniales sp. 2. Foram encontradas três espécies cuja localidade-tipo é a Ásia: Grateloupia orientalis, Grateloupia turuturu e Grateloupia yangjiangensis. Entre os táxons previamente citados para a costa brasileira, nove não foram encontrados. Se os táxons não encontrados constituírem espécies válidas, a diversidade da ordem no Brasil será de 35 espécies. As análises filogenéticas mostraram que os gêneros Cryptonemia, Halymenia e Grateloupia constituem grupos não-monofiléticos. Os resultados demonstraram a existência de ampla diversidade críptica e pseudo-críptica e de espécies e gêneros novos para a ciência, além de revelarem a ocorrência de espécies não nativas. Este estudo contribui substancialmente para o conhecimento da diversidade de algas marinhas na costa brasileira / Algae of Halymeniales (Rhodophyta) present a wide ecological and economic importance, as primary producers and bioactive compounds producers, and include invasive species worldwide. Its taxonomy is quite problematic, with reports of misidentifications and nomenclatural changes. Therefore, studies have included molecular tools to assist the morphological taxonomy of this order. This study aims to investigate through molecular and morphological techniques the diversity of Halymeniales along the Brazilian coast, in order to contribute to the knowledge of native marine flora. Three molecular markers were sequenced, UPA, COI-5P and rbcL, whose data were allied to morphological characters and resulted in 26 delimited species. There are 11 new species to science: Corynomorpha cf. clavata, two taxa morphologically identified as \"Cryptonemia\" crenulata, two taxa morphologically identified as Cryptonemia seminervis, Halymenia ignifera, Halymenia pinnatifida, Halymenia silviae, Grateloupia cf. dichotoma, Grateloupia cf. filicina 1 and Grateloupia cf. filicina 2. At least seven new genera were found, represented by the following taxa: \"Cryptonemia\" bengryi, representatives of \"Cryptonemia\" crenulata complex, \"Cryptonemia\" delicatula, \"Halymenia\" elongata, \"Halymenia\" floridana, Halymeniales sp. 1 and Halymeniales sp. 2. Three species whose type locality is Asia were detected: Grateloupia orientalis, Grateloupia turuturu and Grateloupia yangjiangensis. Among taxa previously recorded to Brazilian coast, nine were not found. If those taxa constitute valid species, the diversity of the order in Brazil will be represented by 35 species. Phylogenetic analyses showed that Cryptonemia, Halymenia and Grateloupia constitute non-monophyletic groups. Results demonstrated the existence of wide cryptic and pseudo-cryptic diversity as well as novel species and genera, and revealed the presence of non-native species

A preliminary experiment was conducted to determine the effects of salinity and moisture stress on the pathogenicity of root-knot nematodes (RKN) in turfgrass plants. The results indicated that RKN infection adversely affected both visual and functional parameters of bentgrass. Salinity and moisture stress further exaggerated the damage caused by RKN. Under well-watered conditions, the effects of SWC and RKN infection on bentgrass plants were studied. Applications of Swe at 0.5 liter ha⁻¹ and 1.0 liter ha⁻¹ effectively enhanced bentgrass growth under both RKN-free and RKN-infected condition. It was shown that RKN caused less damage to SWC-treated plants than to non-treated plants. In addition, a soil drench of 0.5 liter ha⁻¹ and 1.0 liter ha⁻¹ at 10 day intervals was required to enhance bentgrass growth under RKN-free and RKN-infected conditions, respectively. The effects of seven SWC treatments on the growth of nematode-free and RKN infected bentgrass plants were tested under three irrigation regimes. Rooting and leaf moisture parameters, quality and clipping yield were all improved to some degree by SWC applications. High dosage SWC treatments, applied as a soil drench at one liter ha⁻¹ every 10 days, were most effective in improving plant growth. Application of SWC was more beneficial to RKN-infected plants than RKN-free plants, and to abiotically stressed plants than to abiotic stress-free plants. In a separate study, seaweed application was also shown to enhance both top growth and root growth of lance nematode (Hoplolaimus galeatus) or RKN infected bentgrass grown under drought or salinity stress condition. With SWC application, almost all of the symptoms caused by nematode infection and the abiotic stress were partially overcome. In addition, root development, leaf water status and clipping yield were all improved. It was apparent that soil drench SWC treatments were more effective in enhancing bentgrass growth than foliar Swc treatments. Application of SWC slightly reduced the number of nematodes per unit of fresh root (for RKN) and per unit weight of soil (for lance nematodes). Protein extracted from SWC-treated or non-treated ryegrass plants under different stress conditions indicated that SWC altered plant protein synthesis, possibly by inducing selective gene expressions. / Ph. D.

Ma Wing-chi, Joyce. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 131-148). / Abstracts in English and Chinese. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.iv / Acknowledgement --- p.vi / Contents --- p.viii / Abbreviation --- p.xii / List of Tables --- p.xiii / List of Figures --- p.xv / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Literature review --- p.5 / Chapter 2.1 --- Fisheries in Hong Kong --- p.5 / Chapter 2.2 --- Flavor of seafood --- p.6 / Chapter 2.2.1 --- Lipid-derived volatile aroma compounds --- p.7 / Chapter 2.2.2 --- "Alcohols, aldehydes and ketones" --- p.8 / Chapter 2.2.3 --- Enzymatic conversion of sulfur- and nitrogen-containing precursors --- p.9 / Chapter 2.2.4 --- Thermally generated compounds --- p.9 / Chapter 2.2.5 --- Bromophenols --- p.10 / Chapter 2.2.5.1 --- General properties of bromophenols --- p.11 / Chapter 2.2.5.2 --- Threshold of bromophenols --- p.14 / Chapter 2.2.5.3 --- Toxicity of bromophenols --- p.17 / Chapter 2.2.5.4 --- Previous studies about bromophenols --- p.19 / Chapter 2.2.5.5 --- Bromophenols in aquacultured seafood --- p.20 / Chapter 2.2.5.6 --- Possible dietary sources of bromophenols --- p.20 / Chapter 2.2.5.7 --- Possibility of increasing bromophenol content in aquacultured fish --- p.23 / Chapter 2.3 --- Criteria for selecting experimental fish model --- p.24 / Chapter 3. --- Distribution of Bromophenols in selected Hong Kong seafoods --- p.27 / Chapter 3.1 --- Introduction --- p.27 / Chapter 3.2 --- Materials and methods --- p.28 / Chapter 3.2.1 --- Sample collection and preparation --- p.28 / Chapter 3.2.2 --- Simultaneous steam distillation-solvent extraction (SDE) --- p.30 / Chapter 3.2.3 --- Gas chromatography / mass spectrometry (GC/MS) --- p.30 / Chapter 3.2.4 --- Compound identification and quantification --- p.31 / Chapter 3.2.5 --- Recoveries --- p.33 / Chapter 3.2.6 --- Moisture determination --- p.34 / Chapter 3.2.7 --- Statistical analysis --- p.34 / Chapter 3.3 --- Results and discussion --- p.34 / Chapter 3.3.1 --- Distribution of bromophenols in seafoods --- p.34 / Chapter 3.3.1.1 --- Bromophenols in marine fishes --- p.49 / Chapter 3.3.1.2 --- Bromophenols in mollusks --- p.49 / Chapter 3.3.1.3 --- Bromophenols in crustaceans --- p.50 / Chapter 3.3.2 --- Seasonal variations of TBCs --- p.51 / Chapter 3.3.3 --- Bromophenols in diet contents --- p.52 / Chapter 3.3.4 --- Bromophenol contents of freshwater fish --- p.53 / Chapter 3.3.5 --- Relationship between the living habitats and bromophenol contents --- p.56 / Chapter 3.3.6 --- Bromophenols as flavor compounds in seafoods --- p.58 / Chapter 3.4 --- Conclusion --- p.59 / Chapter 4. --- Distribution of Bromophenols in selected Hong Kong seaweeds --- p.61 / Chapter 4.1 --- Introduction --- p.61 / Chapter 4.2 --- Materials and methods --- p.62 / Chapter 4.2.1 --- Sample collection and preparation --- p.62 / Chapter 4.2.2 --- Simultaneous steam distillation-solvent extraction (SDE) --- p.63 / Chapter 4.2.3 --- Gas chromatography / mass spectrometry (GC/MS) --- p.64 / Chapter 4.2.4 --- Compound identification and quantification --- p.65 / Chapter 4.2.5 --- Recoveries --- p.66 / Chapter 4.2.6 --- Moisture determination --- p.67 / Chapter 4.3 --- Results and discussion --- p.67 / Chapter 4.3.1 --- Distribution of bromophenols in marine algae --- p.67 / Chapter 4.3.2 --- Seasonal variations --- p.76 / Chapter 4.3.3 --- Functions of bromophenols in marine algae --- p.79 / Chapter 4.3.4 --- Marine algae as sources of bromophenols in marine environment --- p.80 / Chapter 4.4 --- Conclusion --- p.81 / Chapter 5. --- Enhancement of bromophenol contents in aquacultured fish by the development of bromophenol-rich fish feeds --- p.83 / Chapter 5.1 --- Introduction --- p.83 / Chapter 5.2 --- Materials and methods --- p.85 / Chapter 5.2.1 --- Preparation of fish feeds --- p.85 / Chapter 5.2.2 --- Storage conditions of fish feeds --- p.88 / Chapter 5.2.3 --- Experimental animals --- p.88 / Chapter 5.2.4 --- Solvent and chemicals --- p.90 / Chapter 5.2.5 --- Extraction and quantification of bromophenols --- p.90 / Chapter 5.2.5.1 --- Simultaneous steam distillation-solvent extraction (SDE) --- p.90 / Chapter 5.2.5.2 --- Gas chromatography / mass spectrometry (GC/MS) --- p.91 / Chapter 5.2.5.3 --- Compound identification and quantification --- p.92 / Chapter 5.2.5.4 --- Recoveries --- p.93 / Chapter 5.2.6 --- Moisture determination --- p.94 / Chapter 5.2.7 --- Statistical analysis --- p.94 / Chapter 5.2.8 --- Sensory test --- p.95 / Chapter 5.3 --- Results and discussion --- p.96 / Chapter 5.3.1 --- Bromophenol contents in wild-harvested and aquacultured fish --- p.96 / Chapter 5.3.2 --- Development of bromophenol-rich fish feed --- p.99 / Chapter 5.3.3 --- Effect of feeding the fish with the fish feed developed --- p.105 / Chapter 5.3.4 --- Sensory evaluation on the flesh of the fish fed with different fish feeds --- p.121 / Chapter 5.3.5 --- Growth of the fish fed with different fish feeds --- p.124 / Chapter 5.4 --- Conclusion --- p.126 / Chapter 6. --- General conclusion and significance of the study --- p.128 / References --- p.131

This thesis is an investigation of the natural products deriving from marine algae and cyanobacteria and has resulted in the discovery of eleven new secondary metabolites. The structure elucidations of these new molecules were performed using a variety of spectroscopic techniques. Four new macrolides were isolated and characterized from the Madagascar marine cyanobacterium Geitlerinema sp. These ankaraholides are structurally similar to the potently cytotoxic swinholides and were found to have cytotoxicities ranging from 178 nM to 354 nM against human lung cancer (NCI-H460) and mouse neuro-2a cell lines. Since swinholide-type compounds were previously localized to the heterotrophic bacteria of sponges, these findings raise intriguing questions about their true metabolic source. Geitlerinema sp. was found to be particularly rich in chemistry, and also produced the new linear lipopeptide mitsoamide with unusual structural features including an aminal moiety, a homolysine residue and a polyketide unit (3,7- dimethoxy-5-methyl- nonanedioic acid) (DMNA). A collection of the red marine alga Portieria hornemannii from the south of Madagascar (Tolagniaro, Fort Dauphin), led to the isolation of the previously reported halogenated monoterpene, halomon, and the discovery of three new related metabolites. These molecules were found to inhibit DNA methyltransferase 1 (DNMT-1). As a result of efforts to identify bioactive agents from the marine cyanobacterium Lyngbya majuscula, tanikolide dimer, a novel SIRT2 inhibitor (IC50 = 176 nM), and tanikolide seco-acid were isolated. The depside molecular structure of tanikolide dimer, which is likely a meso compound, was established by NMR, MS and chiral HPLC analyses. The structure of tanikolide dimer raises a number of intriguing configurational and biosynthetic questions for further study. The bioassay guided fractionation of a collection of the brown marine alga Dictyota sp. from Netherland Antilles Playa Fort, led to the identification of a novel HDAC inhibitor with a dolastane carbon skeleton. The novel molecule was also found to possess antimalarial activity. Other known HDAC inhibitors with interesting antimalarial activity have been reported previously, and based on this efficacy against malaria, HDAC appears to be a viable target for the development of antiparasitic agents. / Graduation date: 2006