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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Productivity and Nutrition of Sargassum: A Comparative Ecophysiological Study of Benthic and Pelagic Species in Florida

Unknown Date (has links)
Benthic algal species receive elevated nitrogen (N) and phosphorus (P) availability as anthropogenic activities increase the loading of nutrients into coastal waters. Pelagic species could also be responding to this nutrient enrichment. This study compared the tissue nutrient content and productivity of three benthic and two pelagic species of Sargassum. We hypothesized that the benthic species would have a higher tissue nutrient content and productivity than the pelagic species and the pelagic species would have a higher tissue nutrient content and productivity than historic data. The tissue nutrient content and net productivity of the benthic and pelagic species were not significantly different indicating that the pelagic species are receiving high levels of nutrient availability comparable to that of the benthic species. Pelagic species in the current study exhibited significantly higher N:P ratios and net productivity than the historic data, suggesting a shift from N to P limitation and increased productivity. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
172

Isolation and Structural Elucidation of Novel Bioactive Natural Products from Marine Organisms of the Western Atlantic Ocean

Unknown Date (has links)
The aim of this dissertation was to elaborate the exploration of biologically active secondary metabolites from the marine sponge Cacospongia cf. linteiformis collected from the Bahamas and the soft coral Briareum asbestinum collected from two different sites in Florida State, Boca Raton and Dry Tortugas. In chapter one, a review on previous chemical and biological studies of the marine sponge C. cf. linteiformis and soft coral B. asbestinum is provided. Particular attention is given to spongianolides and briarellins, two important classes of compounds isolated from C. cf. linteiformis and B. asbestinum, respectively, and their structural features and diverse bioactivities. In chapter two, the isolation and relative configuration determination of four epimeric sesterterpenoids, spongianolides E & F (18c, 18d, 19c, 19d) from C. cf. linteiformis collected from the Bahamas are discussed. Thanks to chemical modification (acetylation), diastereomeric 18c&18d and 19c&19d, respectively, were able to be isolated using chromatographic techniques for the first time, and then the relative configurations of 18c, 18d, 19c, 19d were determined based on NOESY NMR experiments. The bioactivity of mixture of compounds 18c, 18d, 19c, 19d were tested and it exhibited inhibition against Schnurri-3 (a regulator of postnatal bone mass). In chapter three, the isolation and structural elucidation of four new compounds, florellins A-D (49-52), from B. asbestinum collected off the coast of Boca Raton, FL are discussed. The molecular structures of these compounds were established by spectroscopic analysis. Compounds 49-52 are the first briarellins containing an acyl group at C-13, while 49 and 50 are the first briarellins possessing acylation at C-15. Florellins A–C (49-51) were screened and found cytotoxic against three human cell lines, BT474, WM266−4 and HEK293. In chapter four, the isolation and structural elucidation of four new compounds, florellins E-H (57-60), from B. asbestinum collected in Dry Tortugas, FL are discussed. The molecular structures of these compounds were established by spectroscopic analysis. Florellins F (58) and H (60) were screened against three human cell lines, BT474, WM266−4 and HEK293, but no cytotoxicity was exhibited. In chapter five, all the experimental procedures are described, including analytical instruments, animal materials, extraction and isolation processes, spectroscopic data and protocols of bioassays. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
173

Atividades antinociceptiva e antiinflamatÃria da lectina da alga marinha vermelha Pterocladiella capilacea (S.G. Gmelin) Santelices & Hommersand / Antinociceptive and anti-inflammatory activities of The lectin from the marine red alga pterocladiella capillacea pc) capilacea (s.g. gmelin) santelices & hommersand

Luana Maria Castelo Melo Silva 22 February 2008 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Lectinas de algas marinhas tÃm-se mostrado importantes ferramentas biotecnolÃgicas. Objetivou-se estudar as atividades antinociceptivas e antiinflamatÃrias da lectina da alga marinha vermelha Pterocladiella capillacea (Pc). A Pc, apresentando atividade hemaglutinante contra eritrÃcitos tripsinizados de coelho, foi obtida a partir da aplicaÃÃo do extrato protÃico total em cromatografia de troca iÃnica em coluna de DEAE-celulose seguida da cromatografia de afinidade em coluna de goma de guar. A seguir, foi utilizada nos ensaios de nocicepÃÃo e inflamaÃÃo, utilizando camundongos machos Swiss e ratos machos Wistar, respectivamente. Pc (0,9; 8,1 ou 72,9 mg/kg; i.v) foi administrada 30 min antes de cada estÃmulo nocigÃnico, ou seja, antes da injeÃÃo i.p de Ãcido acÃtico a 0,8% (10 &#956;L/mL), da injeÃÃo intraplantar de formalina a 1% (20 &#956;L/pata) ou do teste da Placa quente (51Â1 ÂC), e comparada a animais nÃo tratados ou prÃ-tratados com Indometacina ou Morfina, ambas a 5 mg/kg; s.c. Observou-se que a Pc (0,9; 8,1 ou 72,9 mg/kg) reduziu significantemente o nÃmero de contorÃÃes abdominais induzidas pelo Ãcido acÃtico em 29,2%; 39,3%, e 51,9%, respectivamente. Pc (72,9 mg/kg) tambÃm reduziu (p<0,05) a fase 1 (neurogÃnica) e a fase 2 (inflamatÃria) observadas apÃs administraÃÃo da formalina, em 58% e 87%, respectivamente. Entretanto, a Pc (72,9 mg/kg) nÃo foi capaz de reduzir a nocicepÃÃo observada no teste da Placa Quente, quando comparada à morfina. Os efeitos antinociceptivos da Pc foram abolidos quando a Pc foi prÃ-incubada com a glicoproteÃna mucina (1,25 mg/mL), inibidora de sua atividade hemaglutinante. Sugere-se, portanto, que a atividade antinociceptiva da Pc possa ser predominante via inibiÃÃo de mecanismos perifÃricos. Assim, seguiram-se os ensaios de induÃÃo da migraÃÃo neutrofÃlica para cavidade peritoneal ou do edema de pata de ratos por Carragenana (Cg-tipo l; 500 g/cavidade ou pata), onde observou-se que a administraÃÃo da Pc (8,1 mg/kg; i.v) 30 min antes da Cg reduziu significativamente a contagem do nÃmero de neutrÃfilos em 84%. No entanto, a Pc nÃo foi capaz de prevenir o edema de pata induzido pela Cg. Desta forma, sugere-se que esta proteÃna foi capaz de reduzir o mecanismo de migraÃÃo de neutrÃfilos, possivelmente ligando-se à molÃculas especÃficas celulares, como por exemplo, selectinas. Para confirmar sua seguranÃa, a PC (8,1 mg/kg) foi administrada em camundongos diariamente e no 7 dia foram coletadas amostras sanguÃneas para dosagens de urÃia e transaminases (TGO e TGP), e pesados rins e fÃgado. Observou-se que a Pc nÃo causou alteraÃÃes significativas, sugerindo portanto, ser segura no perÃodo de administraÃÃo avaliado. Dessa forma, considerando os dados em conjunto, conclui-se que a Pc possui propriedades antinociceptiva e antiinflamatÃria com aÃÃo perifÃrica. / Marine algae lectins had been showing important biotechnical tools. Our objectives were to study the antinociceptive and anti-inflammatory activities of the lectin from the marine red alga Pterocladiella capillacea (Pc). The Pc, presenting haemagglutinating activity against trypsin-treated erytrocytes from rabbit, was purified by application of crude extract (0.025 M Tris-HCl buffer, pH 7.5) on ion exchange chromatography on DEAE-cellulose followed by affinity chromatography on guar-gum column. To proceed, it was used in the nocicepÃÃo and inflammation assays, using male Swiss mice and male Wistar rats, respectively. Pc (0.9; 8.1 or 72.9 mg/kg; i.v) it was administered 30 min before each challenge, that is, before the injection i.p of acetic acid 0.8% (10 &#956;l/mL), of the intraplantar injection of 1% formalin (20 &#956;L/paw) or of the Hot Plate test (52Â1 ÂC), and compared to non treated animals or to pre-treated by Indomethacin or Morphine, both at 5 mg/kg; s.c. It was observed that the Pc (0.9; 8.1 or 72.9 mg/kg) reduced significantly the number of writhes induced by acetic acid (29.2%; 39.3%, and 51.9%, respectively). Pc (72.9 mg/kg) also reduced (p<0.05) the 1st phase (neurogenic) and the 2nd phase (inflammatory) observed after administration of the formalin (58% and 87%, respectively). However, the Pc (72.9 mg/kg) was not capable to reduce the nociception evaluated by Hot Plate test, compared to morphine. These antinociceptive effects were abolished when the Pc was pre-incubated with mucin (1.25 mg/mL), inhibitory glycoprotein of its haemagglutinating activity. Therefore, it is suggested that the antinociceptive activity of the Pc can be predominant by inhibition of peripheric mechanisms. After this, was realized the assays of neutrophil migration for peritoneal cavity or of the paw edema of mice by Carragenan (Cg-type l; 500 g/cavity or paw), where was observed that the administration of the Pc (8,1 mg/kg) 30 min before Cg reduced the neutrophil counts significantly by 84%. However, Pc was not capable to prevent the paw edema induced by Cg. This way, it is suggested that this protein was capable to reduce neutrophil migration by previous mechanism to migration, possibly linking to cellular specific molecules as, for example, selectins. Then, to confirm its safety, the Pc (8.1 mg/kg) was administered daily in mice and observed their behaviors, and at the 7th day, sanguine samples were collected for urea and transaminases (TGO and TGP) dosages, and heavy kidneys and liver. It was observed that Pc did not cause significant alterations, suggesting be safety for the administration period. Considering the data together, it is ended that the Pc possesses antinociceptive and anti-inflammatory properties with peripheral action.
174

Adição de óleos essenciais e algas marinhas calcárias em dietas para vacas no terço final de lactação / Addition of essential oils and calcareous marine algae in diets of dairy cows during late lactation

Andrés Nelsis Oscar Navarro 03 October 2018 (has links)
As algas marinhas calcárias (AMC) e os óleos essenciais vêm sendo utilizados como aditivos em dietas para ruminantes. As AMC têm sido adicionadas às dietas com o objetivo de modularem o pH ruminal, enquanto os óleos essenciais, através de sua ação antimicrobiana, têm sido testados como alternativa aos aditivos antibióticos na produção animal. Os objetivos do presente estudo foram avaliar os efeitos de óleos essenciais e de algas marinhas calcárias (AMC), bem como a combinação de ambos, sobre desempenho e ambiente ruminal de vacas leiteiras em lactação. Foram realizados 2 experimentos com 32 vacas leiteiras sob sistema de pastejo rotativo com suplementação diária de 6 kg de alimento concentrado por vaca: o experimento 1 foi de desempenho e o experimento 2 de metabolismo ruminal. Em ambos os experimentos as vacas foram submetidas aos seguintes tratamentos: a) controle (CONT); b) óleos essenciais (OE); c) algas marinhas calcárias (AMC); d) AMC + OE. No experimento 1, as variáveis registradas foram consumo, produção e composição do leite, ganho de peso, condição corporal e parâmetros sanguíneos (glicose e ácidos graxos não esterificados [AGNE]). No experimento 2 foram utilizadas as mesmas 32 vacas em lactação para avaliação dos parâmetros ruminais. Os delineamentos utilizados foram: em quadrados latinos replicados (experimento 1) e em blocos inteiramente casualizados (experimento 2). No experimento 1 o CMS de pasto e os CMS e CMO totais foram maiores para o tratamento AMC em comparação com os tratamentos OE e OE+AMC. Os dados de consumo do tratamento CONT foram não diferiram dos demais tratamentos. As digestibilidades da MS e da MO foram maiores para os tratamentos OE e OE+AMC em comparação com o tratamento AMC. Os dados de digestibilidade do tratamento CONT não diferiram dos demais tratamentos. O escore de condição corporal médio foi maior para o tratamento OE em comparação com os demais, porém os aditivos testados não afetaram as concentrações sanguíneas de AGNE e de glicose. Os dados de produção e de composição do leite não foram afetados pelos aditivos testados, assim como os dados de concentração de energia das dietas, consumo de energia, secreção de energia no leite e eficiência de conversão da energia consumida em energia láctea. No experimento 2, a suplementação com OE aumentou a concentração molar de AGV totais e a de acetato em comparação com os tratamentos CONT e AMC, com valores intermediários e não diferentes para o tratamento OE+AMC. Houve aumento do pH ruminal no tratamento AMC em comparação com o tratamento OE. A inclusão de óleos essenciais e ou algas marinhas não alterou a resposta produtiva de vacas leiteiras, apesar do aumento na concentração de AGV e de pH ruminal respectivamente. / Essential oils (OE) and calcareous marine algae (AMC) are being used in ruminants diets. The AMC has been added to diets with the purpose of regulating the ruminal pH while the OE, due to their antimicrobial properties, had been tested as an alternative to the antibiotic additives used in animal production. The objectives of the current study were to evaluate the effects of OE and AMC as well as their interaction on performance and ruminal environment of lactating dairy cows. Two experiments with 32 cows were developed. The animals were in a rotational grazing system supplemented with 6 kg per cow of concentrate feed. Experiment 1 was designed to evaluate performance whereas experiment 2 for ruminal metabolism. During both experiments, cows were assigned to the followings treatments: a) control (CONT); b) blend of essential oils (OE); calcareous marine algae (AMC); d) AMC+OE. In experiment 1, the registered variables were intake, yield and milk composition, live weight, body condition score and blood parameters (glucose and non-esterified fatty acids, [NEFA]). In experiment 2 the same 32 lactating cows were used to evaluate ruminal parameters. The statistical designs used were: replicated Latin square (experiment1) and randomized complete block design (experiment 2). In experiment 1, grass and total DM and OM intakes were increased in AMC compared to OE and OE+AMC. The intakes observed for CONT did not differ from the other treatments. Digestibility of DM and OM were higher for OE and OE+AMC compared to AMC. Digestibility of CONT did not differ from other treatments. The average BCS was higher for OE, however the tested additives did not affect blood concentration of NEFA and glucose. Milk yield and composition were not affected by additives inclusion as well as energy concentration in diets, energy intake, secreted energy in milk and energy conversion efficiency. In experiment 2, OE increased molar concentration of acetate and total VFA when compared to CONT and AMC, but not differed from OE+AMC. The AMC increased ruminal pH when compared to OE. The inclusion of essential oils and/or calcareous marine algae did not alter the productive response of lactating dairy cows, even though there was an increase in VFA concentration and ruminal pH.
175

Eutrophication and excessive Macroalgal growth in Lake Macquarie, New South Wales

Nicholls, David John, School of Biological Science, UNSW January 1999 (has links)
In response to concern that excessive macroalgal growth and accumulation was occurring in some inshore areas of Lake Macquarie, the distribution, abundance and seasonality of macroalgae was investigated in relation to nutrient input and power station cooling water. Macroalgal dry weight biomass was measured at ten sites on a monthly basis for two years, with an analysis of community structure conducted using Multi-Dimensional Scaling. The macroalgal community in Lake Macquarie was typical of those found in other New South Wales coastal lagoons, exhibiting considerable spatial and temporal variation. A close similarity was observed in macroalgal community structure at sites affected by urban nutrient input, these being characterised by a high biomass often attributable to only one or two species. These nuisance macroalgae were mostly green algae, which were almost entirely absent from other sites. Biomass at sites affected by urban nutrient input was generally within the range documented for eutrophic estuaries elsewhere. Analysis of macroalgal community structure showed no evidence of large-scale changes macroalgal communities attributable to the effects of power station cooling water except within 500m of the outfall. At sites affected by a 1-2??C temperature increase, community structure and the magnitude of the biomass were similar to sites deemed as being relatively free of human impact. A reduction in species diversity occurred only within the immediate discharge zone, where water temperatures were approximately 6??C above ambient temperatures. Excessive growth of nuisance macroalgal species was not observed at any of the sites influenced by power station cooling water. There were no distinct patterns in seasonality of macroalgal growth in this study, though the greatest biomass appeared to occur in spring. The irregular temporal variation in macroalgal growth suggests that the most significant factors affecting growth occur on a time scale of weeks to months. It is therefore likely nutrient input to the nearshore through surface runoff is an important influence on the distribution and abundance of macroalgae in Lake Macquarie. This emphasises the need to reduce nitrogen and phosphorus input from urban sources in Lake management.
176

Fine structure of the virus genome in a marine filamentous brown algae, Feldmannia

Lee, Amy M. 18 June 1997 (has links)
Viruses or viruslike particles of eukaryotic algae are ubiquitous in aquatic habitats, however, suprisingly little is known about them. The research presented here focused on one such virus which infects a multicellular filamentous brown alga of the genus Feldmannia. Although preliminary studies had been performed on the genome structure of the Feldmannia sp. Virus (FsV), little was known. The purpose of this study was to analyze the structure of the FsV genome in detail. During the experiments aimed at mapping the FsV genome, cross-hybridization was observed among five BamHI-fragments of the digested FsV DNA. Sequence analysis of one of those fragments revealed the presence of 173 by direct repeats. There are two FsV genomes of different size-classes (158 and 178 kbp). The 173 by repeats in the cross-hybridizing BamHI-fragments were confined to a small region of each virus genome. The number of these repeats in the 178 kbp genome was estimated to be about 109 and in the 158 kbp genome to be about 41. in the 178 kbp genome, the repeats are contained within a 22 kbp region and in the 1.58 kbp genome, the repeats are contained within a 10 kbp region. These viruses are actively replicated in sporophyte plants. A family of related 173 by direct repeats was discovered in an encrypted FsV genome. The family of repeats estimated to be greater than 50 kbp in length were found inserted into a protein kinase gene encoded within the 3.6 kbp viral BamHI-fragment Z. Southern analysis indicates that these repeats in the encrypted FsV genome are distinct from the previously characterized repeats in the amplified FsV genome. The translated protein kinase shares highest homologies to the SNF1 subfamily of serine/threonine protein kinases and contains a potential autophosphorylation site in a region unique to this protein kinase. A DNA polymerase gene was identified in the FsV genome. The predicted peptide sequence of the FsV DNA polymerase gene contains all of the conserved motifs found in B-family (a-like) DNA polymerases. A TTTTTNT sequence motif shown to be a transcription termination signal for Vaccinia virus early genes is found at the 3' end of the DNA polymerase gene. Phylogenetic analysis of the FsV DNA polymerase gene and other viral DNA polymerase genes indicates that FsV belongs to a group of algal viruses recently defined as Phycodnaviridae. / Graduation date: 1998
177

Novel oxylipins and heterocycles from the Rhodophyta and Cyanophyta

Jiang, Zhi-dong 07 May 1992 (has links)
Graduation date: 1992
178

Structural and biosynthetic studies on marine eicosanoids and other oxylipins

Moghaddam, Mehran Fallah 29 October 1991 (has links)
Graduation date: 1992
179

A test of optimal defense theory vs. the growth-differentiation balance hypothesis as predictors of seaweed palatability and defenses

Heckman, Melanie L. 31 August 2011 (has links)
Because organisms have limited resources to allocate to multiple life history traits, the Optimal Defense Theory (ODT) and the Growth-Differentiation Balance Hypothesis (GDBH) were developed by terrestrial plant ecologists to predict intraindividual defense allocation based on the cost of defense and these life history trade-offs. However, these theories have garnered equivocal experimental support over the years and are rarely experimentally extended from predictions of plant physiology to the palatability of the tissues an herbivore experiences. We therefore examined tissue palatability, nutritional value, and defense mechanisms in multiple Dictyotalean seaweeds in two Caribbean locations, using two herbivores. Relative palatability of tissues varied greatly with algal species, grazer species, and location. Because older bases were not consistently defended, GDBH did not predict relative palatability. We could not reject ODT without intensive measures of tissue fitness value and herbivore risk, and this theory was therefore not useful in making broad predictions of tissue palatability. In testing the physiological predictions of these theories, we found the young, growing apices of these seaweeds to be generally more nutritionally valuable than the old, anchoring bases and found organic-rich apices to be more chemically deterrent, thus supporting ODT. However, the combined chemical, nutritional, and structural traits of these algae all influenced herbivore choice. As a result, these patterns of apical value and chemical defense reflected palatability of live tissues for only one of five algal species, which rendered ODT and GDBH poor predictors of relative palatability for most algae.
180

Primary colonisation of submerged artificial substrates with special reference to marine macroalgae /

Cheung, Kwok-wai. January 1986 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1987.

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