109 results on '"Vieira, Armando Augusto Henriques"'
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2. Analysis of major carotenoids and fatty acid composition of freshwater microalgae
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Soares, Aline Terra, da Costa, Dayane Cristina, Vieira, Armando Augusto Henriques, and Antoniosi Filho, Nelson Roberto
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- 2019
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3. Productivity and rainfall drive bacterial metabolism in tropical cascading reservoirs
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Freitas, Roberta, Vieira, Helena Henriques, de Moraes, Guilherme Pavan, de Melo, Michaela Ladeira, Vieira, Armando Augusto Henriques, and Sarmento, Hugo
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- 2017
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4. Regional factors as major drivers for microbial community turnover in tropical cascading reservoirs
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Vieira, Helena Henriques, primary, Bagatini, Inessa Lacativa, additional, de Moraes, Guilherme Pavan, additional, Freitas, Roberta Mafra, additional, Sarmento, Hugo, additional, Bertilsson, Stefan, additional, and Vieira, Armando Augusto Henriques, additional
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- 2022
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5. The Culture Collection of Freshwater Microalgae from the Federal University of São Carlos (CCMA-UFSCar), Brazil
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Bagatini, Inessa Lacativa, Vieira, Armando Augusto Henriques, Flaim, Giovanna, and Nava, Veronica
- Abstract
Bagatini IL, Vieira AAH. 2022. The Culture Collection of Freshwater Microalgae from the Federal University of São Carlos (CCMA-UFSCar), Brazil. SILnews 80.
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- 2022
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6. Role of Hydrophobic Extracellular Polysaccharide of Aulacoseira granulata (Bacillariophyceae) on Aggregate Formation in a Turbulent and Hypereutrophic Reservoir
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Vieira, Armando Augusto Henriques, Ortolano, Pedro Ivo Coelho, Giroldo, Danilo, Oliveira, Maria José Dellamano, Bittar, Thais Beraldo, Lombardi, Ana Teresa, Sartori, Antonio Luiz, and Paulsen, Berit Smestad
- Published
- 2008
7. Corrigendum to “Use of fatty acids in the chemotaxonomy of the family Selenastraceae (Sphaeropleales, Chlorophyceae)” [Phytochemistry 151 (2018) 9–16]
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Mori, Cilene Cristina, Bagatini, Inessa Lacativa, da Silva, Thais Garcia, Parrish, Christopher Charles, and Vieira, Armando Augusto Henriques
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- 2021
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8. The influence of cyanobacterium exudates on copper uptake and toxicity to a tropical freshwater cladoceran
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Choueri, Rodrigo Brasil, Gusso-Choueri, Paloma Kachel, Melão, Maria da Graça Gama, Lombardi, Ana Teresa, and Vieira, Armando Augusto Henriques
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- 2009
9. The metal binding capacity of Anabaena spiroides extracellular polysaccharide: an EPR study
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Freire-Nordi, Cristina Souza, Vieira, Armando Augusto Henriques, and Nascimento, Otaciro Rangel
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- 2005
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10. Estabelecimento de um biobanco criopreservado para a Coleção de Culturas de Microalgas de Água-Doce (CCMA-UFSCar), São Paulo, Brasil
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Tessarolli,Leticia Piton, Day,John Godfrey, and Vieira,Armando Augusto Henriques
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Cryopreservation ,biobank ,criopreservação ,microalgas de água-doce ,biobancos ,freshwater microalgae - Abstract
The Culture Collection of Freshwater Microalgae (CCMA-UFSCar, Coleção de Culturas de Microalgas de Água-Doce), based at the Universidade Federal de São Carlos, plays an important role in underpinning Brazilian microalgal research, providing biological materials, substrates and training personnel for a large proportion of the past and current projects in this area. However, recent efforts to expand the culture catalogue/holdings have reached a ceiling because of the logistical practicality of maintaining actively growing cultures. In order to reduce the costs associated with the maintenance regime of cultures, efforts were initiated on the establishment of a cryopreserved biobank for long term maintenance of cultures, thus minimizing the efforts associated with handling of material, as successfully frozen cultures, in theory, could be maintained effectively indefinitely, with the advantage of the stability of cells characteristics. Initial tests were performed on 93 strains including exemplar taxa across the different taxonomic groups in the collection catalogue. The highest levels of success were achieved for the smaller taxa, such as the small green algae; while for the larger and more complex organisms limited to no success was obtained. For the strains tested, over 70% had positive good levels of post-thaw viability and regenerated phenotypically normal cultures. Resumo A Coleção de Culturas de Microalgas de Água-Doce (CCMA-UFSCar), localizada na Universidade Federal de São Carlos tem um importante papel na sustentação da pesquisa brasileira em microalgas, provendo material biológico, substratos e treinamento de pessoal para uma grande fração dos projetos atuais nessa área. Entretanto, os recentes esforços para expandir o catálogo de culturas atingiram um limite máximo em praticidade logística para a manutenção de culturas metabolicamente ativas. Buscando reduzir os custos do regime de manutenção das culturas, foi-se iniciado o estabelecimento de um banco criopreservado para a manutenção em longo prazo desses organismos, minimizando os gastos com manuseio do material, visto que culturas congeladas com sucesso podem, em teoria, serem mantidas por prazos indeterminados, ainda com a vantagem da estabilidade das características nas culturas. Testes iniciais foram realizados com 93 linhagens, incluindo organismos de diferentes grupos taxonômicos mantidos na coleção de culturas. As maiores taxas de sucesso foram observadas nos organismos menores, como as pequenas algas verdes, enquanto os organismos maiores e mais complexos obtiveram sucesso limitado. Em geral, para as linhagens testadas, acima de 70% dos organismos apresentaram resposta positiva ao processo.
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- 2017
11. Region Growing for Segmenting Green Microalgae Images
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Borges, Vinicius R. P., primary, Oliveira, Maria Cristina F. de, additional, Silva, Thais Garcia, additional, Vieira, Armando Augusto Henriques, additional, and Hamann, Bernd, additional
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- 2018
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12. Selenastraceae (Sphaeropleales, Chlorophyceae): rbcL, 18S rDNA and ITS-2 secondary structure enlightens traditional taxonomy, with description of two new genera, Messastrum gen. nov. and Curvastrum gen. nov.
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Garcia da Silva, Thaís, primary, Bock, Christina, additional, Sant'Anna, Célia Leite, additional, Bagatini, Inessa Lacativa, additional, Wodniok, Sabina, additional, and Vieira, Armando Augusto Henriques, additional
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- 2017
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13. Establishment of a cryopreserved biobank for the Culture Collection of Freshwater Microalgae (CCMA-UFSCar), São Paulo, Brazil
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Tessarolli, Leticia Piton, primary, Day, John Godfrey, additional, and Vieira, Armando Augusto Henriques, additional
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- 2017
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14. tufA gene as molecular marker for freshwater Chlorophyceae
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Vieira, Helena Henriques, primary, Bagatini, Inessa Lacativa, additional, Guinart, Carla Marques, additional, and Vieira, Armando Augusto Henriques, additional
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- 2016
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15. Avaliação da potencialidade de microalgas dulcícolas como fonte de matéria-prima graxa para a produção de biodiesel
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Menezes, Rafael Silva, Leles, Maria Inês Gonçalves, Soares, Aline Terra, Franco, Pedro Ivo Brandão e Melo, Antoniosi Filho, Nelson Roberto, Sant'Anna, Célia Leite, and Vieira, Armando Augusto Henriques
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microalgae ,food and beverages ,biodiesel ,transesterification - Abstract
In this work, the fatty acid quantity and composition of six freshwater microalgae and soybean grains was determined by direct transesterification and gas chromatography analysis. The results showed that all the freshwater microalgae species presented a higher quantity of fatty acid than soybean grain. Choricystis sp. (A) provides 115% more fatty acids per gram of biomass than soybean grain. With regard to the fatty acid composition, Choricystis sp. (A) showed an adequate proportion of saturated and unsaturated fatty acids, with lower quantity of polyunsaturated fatty acids and, akin to some marine microalgae, constitutes an alternative raw material for biodiesel production.
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- 2013
16. Productivity and rainfall drive bacterial metabolism in tropical cascading reservoirs.
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Freitas, Roberta, de Melo, Michaela Ladeira, Sarmento, Hugo, Vieira, Helena Henriques, de Moraes, Guilherme Pavan, and Vieira, Armando Augusto Henriques
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MICROBIAL respiration ,RESERVOIRS & the environment ,TROPHIC state index ,BACTERIAL growth ,CARBON cycle ,RAINFALL frequencies -- Environmental aspects - Abstract
Tropical reservoirs are main carbon sources to the atmosphere, and bacterial metabolism is a key process in these emissions. Here, we explored the drivers of bacterial metabolism in four tropical cascading reservoirs forming a trophic state gradient, and compared them with those found in the literature (mainly from temperate regions). Bacterial production (BP) and growth efficiency (BGE) responded to trophic state-related variables, while bacterial respiration (BR) was weakly and negatively correlated to dissolved organic carbon (DOC). BP and BGE were higher in reservoirs with higher primary production, while BR (high throughout the whole study period) was greater in less productive reservoirs, where planktonic communities were often limited by phosphorus. The high BR and low BGE observed in less productive downstream reservoirs (i.e., less nutrients and organic matter availability) may be explained by increasing nutrient limitation and proportion of recalcitrant DOC along the cascade. Despite the lower productivity, oligotrophic reservoirs may be more important in terms of carbon biogeochemistry, considering that microbes in those systems mineralize more carbon than upstream productive reservoirs. Moreover, the drivers of bacterial metabolism may act differently according to latitude, as seasonality in the tropics is determined mainly by rainfall rather than temperature. [ABSTRACT FROM AUTHOR]
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- 2018
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17. Chemical behavior of Cu, Zn, Cd, and Pb in a eutrophic reservoir: speciation and complexation capacity
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Tonietto, Alessandra Emanuele, primary, Lombardi, Ana Teresa, additional, Choueri, Rodrigo Brasil, additional, and Vieira, Armando Augusto Henriques, additional
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- 2015
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18. Carbohydrate release by a subtropical strain of spondylosium pygmaeum (zygnematophyceae): influence of nitrate availability and culture aging
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Piedras, Fernanda Reinhardt, Baisch, Paulo Roberto Martins, Machado, Maria Isabel Corrêa da Silva, Vieira, Armando Augusto Henriques, and Giroldo, Danilo
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Carbohydrate ,Spondylosium ,Desmid ,Growth ,Nitrate - Abstract
This paper describes the influence of nitrate availability on growth and release of dissolved free and combined carbohydrates (DFCHOs and DCCHOs) produced by Spondylosium pygmaeum (Cooke) W. West (Zygnematophyceae). This strain was isolated from a subtropical shallow pond, located at the extreme south of Brazil (Rio Grande, RS). Experiments were carried out in batch culture, comparing two initial nitrate levels (10 ⁄ 100 lM) in the medium. Growth was monitored by direct microscopic cell counts and chl a content. Nitrate consumption was determined by ion chromatography, while the production of extracellular carbohydrates was monitored by the phenol-sulfuric method. The monosaccharide compositions of DFCHOs and DCCHOs were determined in each growth phase byHPLC with pulse amperometric detection (HPLCPAD). At the end of the experiment, the total composition of extracellular polysaccharide (EPS) molecules >12 kDa was determined by gas chromatography. Nitrate availability had no influence on S. pygmaeum cell density at any phase. On the other hand, chl a content decreased after a few days growth when the availability of nitrate was restricted, but continued to rise when nitrate was plentiful. Also, nitrate depletion was faster at 10 lM nitrate. No influence of the growth phase or nitrate availability on the total carbohydrates (TDCHOs) released per cell was observed. Only DCCHOs were released by S. pygmaeum, and the composition varied between growth phases, especially at lower nitrate availability. EPS molecules >12 kDa were composed mainly of xylose, fucose, and galactose, as for other desmids. However, a high N-acetyl-glucosamine content was found, uniquely among desmid EPSs.
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- 2010
19. Fourier Transform Infrared with Attenuated Total Reflectance Applied to the Discrimination of Freshwater Planktonic Coccoid Green Microalgae
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Moraes, Guilherme Pavan de, primary and Vieira, Armando Augusto Henriques, additional
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- 2014
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20. Perda de Matéria Orgânica Dissolvida por Células de Microcystis Aeruginosa Expostas a Altas Intensidades de Luz
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Dos Santos, Roseli Machado, Vieira, Armando Augusto Henriques, Dellamano Oliveira, Maria José, and Salomoni, Saionara Eliane
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- 2007
21. Chaotropic effect of lithium íon on permeability of polysaccharide capsule of the microalga Ankistrodesmus gracilis (Reinsch) Korsikov (Chlorophyceae)
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Nordi,Cristina Souza Freire, Cavagliere,Thays Gabrielle Wenzel Ferreira, Vieira,Armando Augusto Henriques, and Nascimento,Otaciro Rangel
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Ankistrodesmus gracilis ,marcador de spin e tempo de permeação ,spin label and permeation ,cápsula polissacarídica ,LiCl ,polysaccharide capsule - Abstract
O objetivo deste trabalho foi investigar o efeito caotrópico do íon Li+ na cápsula polissacarídica da microalga colonial Ankistrodesmus gracilis. Esta microalga possui uma cápsula extensa e contínua que envolve completamente as células. Neste estudo, foram utilizados a técnica de Ressonância Paramagnética Eletrônica (RPE) e o marcador de spin - Tempo (2,2,6,6-tetrametilpiperidine-1-oxil), de natureza não reativa. A técnica de RPE é utilizada para monitorar o tempo de difusão dos marcadores de spin através da cápsula polissacarídica, parede e membrana celular, até o interior da célula, onde eles perdem suas propriedades paramagnéticas. O íon Li+ utilizado tem a propriedade de provocar a desorganização estrutural da cápsula e, em conseqüência, a modificação do tempo de difusão do marcador de spin. Observou-se que os tempos de decaimento do sinal paramagnético nas células tratadas com Li+ são sempre menores do que nas células não expostas ao Li+ e que os tempos de difusão diminuem com o aumento da concentração de LiCl . As fotomicrografias das algas mostram que a partir da concentração de LiCl 1,0 M, as cápsulas são totalmente retiradas, resultando em células que se aglutinam formando grumos. Também foi constatada a morte das células acima quando expostas a concentração de LiCl acima de 1,0 M. The aim of this study was to investigate the role of chaotropic effect of Li+ on the polysaccharide sheath of the microalga Ankistrodesmus gracilis (Chlorophyceae, Chlorococales) in the selective permeability and transport of molecules in the interior of the cell. The colonial microalga Ankistrodesmus gracilis has a relatively large and continuous mucilaginous sheath. The Electron Paramagnetic Resonance (EPR) was applied using the spin label- Tempo 2,2,6,6-tetramethylpiperidine-1-oxyl of non-reactive nature to study its diffusion coefficients across the polysaccharide envelope. The EPR technique is used to monitor the spin labels diffusion time across the polysaccharide capsule, cell wall and membrane into the interior of the cell, where they lose their paramagnetic properties. The lithium ion (Li+) has the property to structurally disorganize the polysaccharide capsule and the spin label diffusion changes producing different spin label time decay. The time decays of cells subjected to Li+ treatment are faster than the cells without this ion usage and the decay time decreases with increasing Li+ concentration. The photomicrographies show the complete removal of the cell capsule from LiCl 1,0 M upward and as a result, the algal cells agglutinate producing cell clumps, and the algal cells are clearly died.
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- 2006
22. Formação de agregados em culturas de Aulacoseira granulata (Bacillariophyceae) axênicas e inoculadas com bactérias
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Vieira, Armando Augusto Henriques, Giroldo, Danilo, and Ortolano, Pedro Ivo Coelho
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Aggregates ,Bacterial growth ,Degradação microbiana ,Microbial degradation ,Crescimento bacteriano ,Aulacoseira granulata ,Polissacarídeo extracelular ,Agregados ,Extracellular polysaccharide - Abstract
Aggregate formation in axenic and microbial co-inoculated batch cultures of Aulacoseira granulata (Bacillariophyceae). Aggregate formation involving diatoms is a well-known process, especially in the marine environment. The aim of this paper was to observe natural aggregates formation in axenic and microbial co-inoculated cultures of the freshwater diatom Aulacoseira granulata. The growth of bacteria and A. granulata were also monitored, as were qualitative alterations in the composition of the extracellular polysaccharide (EPS) produced by A. granulata in both axenic and microbial co-inoculated cultures. Aggregates were naturally formed in both conditions and our results suggested that the aggregation process increased significantly in the presence of a microbial community from Barra Bonita Reservoir. A. granulata biomass formation also significantly increased along bacterial growth and the EPS composition found in the microbial co-inoculated cultures was different to that of the axenic cultures. Rhamnose proportion increased around 50 % in microbial co-inoculated cultures, probably due to bacterial activity, increasing the hydrophobic properties of the EPS. The aggregation increase in the microbial co-inoculated cultures was correlated to the enhancement of the EPS hydrophobic nature, as well as to the biomass increase of A. granulata. A formação de agregados envolvendo diatomáceas é já um processo bem conhecido, especialmente em ambientes marinhos. O objetivo deste trabalho foi observar a formação espontânea de agregados em culturas de Aulacoseira granulata axênicas e inoculadas com bactérias. O crescimento de bactérias e de A. granulata foi monitorado bem como as alterações qualitativas, causadas pela atividade bacteriana, na composição do polissacarídeo extracelular (EPS) liberado pela diatomácea em ambas as culturas. A formação de agregados ocorreu em ambas as culturas, mas os resultados sugerem que a agregação aumenta significantemente na presença de bactérias de populações oriundas do reservatório de Barra Bonita, também o local de origem da diatomácea. A biomassa de A. granulata aumentou significantemente na presença de bactérias e a composição do EPS nas culturas contaminadas foi diferente daquele das culturas axênicas. A atividade bacteriana aumentou a porcentagem do monossacarídeo Ramnose em cerca de 50 % nas culturas contaminadas, aumentando as propriedades hidrofóbicas do EPS. Assumimos que o aumento da hidrofobicidade bem como o aumento da biomassa de A. granulata nas culturas contaminadas foram os fatores responsáveis pelo aumento da agregação dos filamentos de A. granulata nas culturas contaminadas.
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- 2006
23. Polymeric and free sugars released by three phytoplanktonic species from a freshwater tropical eutrophic reservoir
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Giroldo, Danilo and Vieira, Armando Augusto Henriques
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Several studies have focused on the release of carbohydrates by phytoplankton because of the ecological significance of such compounds. This process increases the supply of carbon to the heterotrophic community, enhancing the phytoplankton/bacteria associations. In this article, we report investigations on the carbohydrate release, both polymeric and free sugars, in axenic batch cultures of three tropical freshwater phytoplanktonic species from different taxonomic positions: Cryptomonas tetrapyrenoidosa (Cryptophyceae), Staurastrum orbiculare (Zygnematophyceae) and Thalassiosira sp. (Bacillariophyceae). The total carbohydrate release rate was increased in the stationary growth phase in all the species under study. Most of the carbohydrates released by the three species were present in the polymeric form, although both polymeric and free carbohydrates could supply carbon enough to support bacterioplanktonic populations, according to rates of consumption found on literature. The composition of the carbohydrates differed significantly from one species to another, indicating that carbohydrate release might be a speciesspecific process. We also observed that the contributions of some components from polymeric sugars, such as fucose, rhamnose and arabinose increased with the advancing age of the cultures.
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- 2005
24. Host-Specificity and Dynamics in Bacterial Communities Associated with Bloom-Forming Freshwater Phytoplankton
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Bagatini, Inessa Lacativa, primary, Eiler, Alexander, additional, Bertilsson, Stefan, additional, Klaveness, Dag, additional, Tessarolli, Letícia Piton, additional, and Vieira, Armando Augusto Henriques, additional
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- 2014
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25. Relative increase of deoxy sugars during microbial degradation of an extracellular polysaccharide released by a tropical freshwater thalassiosira sp, (bacillariophyceae)
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Giroldo, Danilo, Vieira, Armando Augusto Henriques, and Paulsen, Berit Smestad
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Microbial degradation ,Carbohydrate release ,Thalassiosira ,Diatom ,EPS - Abstract
The aim of this study was to characterize the extracellular polysaccharides (EPS) released by a freshwater Thalassiosira sp. (Bacillariophyceae) and evaluate their degradation by heterotrophic microbial populations from the same habitat of Thalassiosira sp., a tropical eutrophic reservoir. The EPS were purified by anion exchange column chromatography, the monosaccharide composition was determined by GC, and the linkages of the monosaccharides by GC-MS. The EPS is a mannose-rich heteropolysaccharide composed of two different acidic fractions. Both of these fractions are composed of mannose, rhamnose, fucose, xylose, galactose, glucose, glucuronic acid, and N-acetyl glucosamine but with different proportions. N-acetyl galactosamine occurs only in fraction 1 and galacturonic acid only in fraction 2. We monitored the concentrations of the monosaccharides in the EPS during its degradation using pulse amperometric detection in an HPLC. The decay patterns of the monosaccharides were varied and the deoxy sugars, fucose and rhamnose, were degraded at a slower rate than the other components, increasing their relative concentrations and the hydrophobic feature of the EPS. The possibility of a selective degradation, which enhances the stickiness of the EPS, promoting transparent exopolymeric particles and aggregate formation, is discussed based on the literature data.
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- 2003
26. An extracellular sulfated fucose-rich polysaccharide produced by a tropical strain of cryptomonas obovata (cryptophyceae)
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Giroldo, Danilo and Vieira, Armando Augusto Henriques
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Cryptophyceae ,Nitrate depletion ,Cryptomonas obovata ,Irradiance ,Extracellular polysaccharide ,Fucose - Abstract
A tropical strain of Cryptomonas obovata Skuja, isolated from a shallow oxbow lake, released a sulfated fucoserich polysaccharide. The polysaccharide is composed mainly of fucose (42%), N-acetyl-galactosamine (26%) and rhamnose (15%), with small quantities of glucuronic acid, mannose, galactose, xylose and glucose. Sulfate accounted for 1.7% total polysaccharide. Quantitative release was studied with cells exposed to optimal culture conditions contrasted with high irradiance and nitrate depletion. This latter set of conditions could simulate stress situati ons usually found in the place from which this strain was isolated. The monosaccharide composition of the polysaccharide was evaluated using PAD-HPLC and gas chromatography. The two irradiances tested (165 mol m−2 s−1 and 2000 mol m−2 s−1) had no significant effect on amounts of polysaccharide released by the cells. Differences were observed when the nitrate availability was varied. In the nitrate-depleted situation, extracellular polysaccharide production was 2.5 times higher than replete cells after 6 h at 165 mol m−2 s−1, and 2.25 times higher at 2000 mol m−2 s−1.
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- 2002
27. Carotenogênese em células de Haematococcus pluvialis induzidas pelos estresses luminoso e nutricional
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Nunes, Moira, primary, Vieira, Armando Augusto Henriques, additional, Pinto, Ernani, additional, Carneiro, Ronaldo Leal, additional, and Monteiro, Antonio Carlos, additional
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- 2013
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28. Avaliação da potencialidade de microalgas dulcícolas como fonte de matéria-prima graxa para a produção de biodiesel
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Menezes, Rafael Silva, primary, Leles, Maria Inês Gonçalves, additional, Soares, Aline Terra, additional, Franco, Pedro Ivo Brandão e Melo, additional, Antoniosi Filho, Nelson Roberto, additional, Sant'Anna, Célia Leite, additional, and Vieira, Armando Augusto Henriques, additional
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- 2013
- Full Text
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29. Glycolytic activities in size-fractionated water samples: emphasis on rhamnosidase, arabinosidase and fucosidase activities
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Colombo-Corbi, Vanessa, primary, Dellamano-Oliveira, Maria José, additional, and Vieira, Armando Augusto Henriques, additional
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- 2011
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30. CARBOHYDRATE RELEASE BY A SUBTROPICAL STRAIN OF SPONDYLOSIUM PYGMAEUM (ZYGNEMATOPHYCEAE): INFLUENCE OF NITRATE AVAILABILITY AND CULTURE AGING1
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Piedras, Fernanda Reinhardt, primary, Baisch, Paulo Roberto Martins, additional, Da Silva Machado, Maria Isabel Corrêa, additional, Vieira, Armando Augusto Henriques, additional, and Giroldo, Danilo, additional
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- 2010
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31. TRANSPARENT EXOPOLYMER PARTICLES FORMATION FROM CAPSULES OFANABAENA SPIROIDES(CYANOBACTERIA) IN CULTURE
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Bittar, Thais Beraldo, primary and Vieira, Armando Augusto Henriques, additional
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- 2010
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32. RELEASE OF CARBOHYDRATES AND PROTEINS BY A SUBTROPICAL STRAIN OFRAPHIDIOPSIS BROOKII(CYANOBACTERIA) ABLE TO PRODUCE SAXITOXIN AT THREE NITRATE CONCENTRATIONS
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Yunes, João Sarkis, primary, De La Rocha, Sabrina, additional, Giroldo, Danilo, additional, Silveira, Savenia Bonoto da, additional, Comin, Rubens, additional, Bicho, Miriam da Silva, additional, Melcher, Silvia Susanne, additional, Sant’anna, Célia Leite, additional, and Vieira, Armando Augusto Henriques, additional
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- 2009
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33. Toxicity of ionic copper to the freshwater microalga Scenedesmus acuminatus (Chlorophyceae, Chlorococcales)
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Lombardi, Ana Teresa, primary, Hidalgo, Thais Moreirados Reis, additional, Vieira, Armando Augusto Henriques, additional, and Sartori, Antonio Luiz, additional
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- 2007
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34. Carboidratos dissolvidos do reservatório de Barra Bonita (Estado de São Paulo, Brasil) e sua relação com as algas fitoplanctônicas abundantes
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Dellamano-Oliveira, Maria José, primary, Colombo-Corbi, Vanessa, additional, and Vieira, Armando Augusto Henriques, additional
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- 2007
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35. Efeito caotrópico do íon lítio na permeabilidade da cápsula polissacarídica da microalga Ankistrodesmus gracilis (Reinsch) Korsikov (Chlorophyceae)
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Nordi, Cristina Souza Freire, primary, Cavagliere, Thays Gabrielle Wenzel Ferreira, additional, Vieira, Armando Augusto Henriques, additional, and Nascimento, Otaciro Rangel, additional
- Published
- 2006
- Full Text
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36. Polymeric and free sugars released by three phytoplanktonic species from a freshwater tropical eutrophic reservoir
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Giroldo, Danilo, primary and Vieira, Armando Augusto Henriques, additional
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- 2005
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37. RELATIVE INCREASE OF DEOXY SUGARS DURING MICROBIAL DEGRADATION OF AN EXTRACELLULAR POLYSACCHARIDE RELEASED BY A TROPICAL FRESHWATER THALASSIOSIRA SP. (BACILLARIOPHYCEAE)1
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Giroldo, Danilo, primary, Vieira, Armando Augusto Henriques, additional, and Paulsen, Berit Smestad, additional
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- 2003
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38. Transport of spin-labelled molecules through the capsule of Nephrocytium lunatum (Chlorococcales) studied by electron paramagnetic resonance
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Freire-Nordi, Cristina Souza, primary, Vieira, Armando Augusto Henriques, additional, and Nascimento, Otaciro Rangel, additional
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- 2003
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39. STRUCTURE OF THE CAPSULAR AND EXTRACELLULAR POLYSACCHARIDES PRODUCED BY THE DESMID SPONDYLOSIUM PANDURIFORME (CHLOROPHYTA)1
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Paulsen, Berit Smestad, primary and Vieira, Armando Augusto Henriques, additional
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- 1994
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40. TRANSPARENT EXOPOLYMER PARTICLES FORMATION FROM CAPSULES OF ANABAENA SPIROIDES (CYANOBACTERIA) IN CULTURE.
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Bittar, Thais Beraldo and Vieira, Armando Augusto Henriques
- Subjects
- *
DEVELOPMENTAL biology , *PHARMACEUTICAL encapsulation , *POLYMERS , *CELL proliferation , *STAINS & staining (Microscopy) - Abstract
We report the production of large numbers of transparent exopolymer particles (TEP) from polysaccharidic capsules of Anabaena spiroides Kleb. in cultures. Two biotic pathways of TEP formation were observed: (1) fragmentation of small portions of the capsules, which occurred throughout the growth phases; and (2) transformation of the whole polysaccharidic capsules into TEP, following cellular lyses in the aging culture. Photographic documentation of these processes was performed after staining small aliquots of the samples with Alcian Blue and negative staining with India ink. Concentrations of TEP were determined in distinct culture growth phases using semiquantitative Alcian Blue staining. Concentrations of TEP increased throughout the experimental time, while Alcian Blue remaining in solution decreased. Decreasing concentrations of chl a indicated cellular death, and by the end of the experiment, TEP formed by both pathways accumulate in the culture medium. These results show that virtually all dead chains of A. spiroides are transformed into TEP in the aged culture. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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41. RELEASE OF CARBOHYDRATES AND PROTEINS BY A SUBTROPICAL STRAIN OF RAPHIDIOPSIS BROOKII (CYANOBACTERIA) ABLE TO PRODUCE SAXITOXIN AT THREE NITRATE CONCENTRATIONS.
- Author
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Yunes, João Sarkis, De La Rocha, Sabrina, Giroldo, Danilo, da Silveira, Savenia Bonoto, Comin, Rubens, Bicho, Miriam da Silva, Melcher, Silvia Susanne, Sant'anna, Célia Leite, and Vieira, Armando Augusto Henriques
- Subjects
CARBOHYDRATES ,PARALYTIC shellfish poisoning ,ORGANIC compounds ,BIOMOLECULES ,CHROMATOGRAPHIC analysis ,BIOPOLYMERS ,GLUCOSAMINE - Abstract
Raphidiopsis brookii P. J. Hill (cyanobacteria) was isolated from a small subtropical eutrophic pond (Biguá Pond) located in the grounds of Rio Grande University in the extreme south of Brazil, following a toxic bloom of this species. Growth, saxitoxin production, and release of carbohydrates and protein were monitored at three sodium nitrate concentrations (500, 1,000, and 1,500 μM), from inoculation up to the stationary growth phase. Growth was monitored by determining the biovolume, chl content, and trichome count. Growth was better described in terms of biovolume and chl measurements, because trichome fragmentation was observed to increase at the stationary growth phase. Carbohydrates and proteins were released in small amounts during most of the experiment, with a significant increase during the stationary phase. Extracellular polysaccharides were essentially composed of glucose, galactose, N-acetyl-glucosamine, mannose, xylose, rhamnose, arabinose, and fucose. The relative proportions of these units showed no significant variation during growth. Small quantities of extracellular free carbohydrates were also detected, and only fucose was released in significant amounts at the lowest nitrate concentration (500 μM). R. brookii produced both saxitoxin and dc-saxitoxin, the former at four times the rate of the latter. This was the first study demonstrating saxitoxin production and the release of both carbohydrate and protein by R. brookii. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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42. Toxicity of ionic copper to the freshwater microalga Scenedesmus acuminatus (Chlorophyceae, Chlorococcales).
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Lombardo, Ana Teresa, Dos Reis Hidalgo, Thais Moreira, Vieira, Armando Augusto Henriques, and Sartori, Antonio Luiz
- Subjects
GREEN algae ,CHLOROCOCCALES ,COPPER ,TOXICITY testing ,MICROALGAE ,CHLOROPHYLL - Abstract
Metal ecotoxicity testing with microalgae is subject to interferences such as change in bioavailable metal fraction by excreted metabolites. Moreover, high metal loads are usually necessary for obtaining 50% effect concentration (EC50) values based on cell number or chlorophyll a. Thus, sensitive parameters, which promptly respond to low dissolved metal variations at environmentally relevant concentrations, are much needed. The genus Scenedesmus, a coenobium-forming freshwater microalga, is cosmopolitan and inhabits pristine and contaminated waters. The present investigation addressed cellular phenotypic alterations in Scenedesmus acuminatus (Largerheim) Chodat 1902 caused by the presence of copper. Copper toxicity to the alga was investigated under laboratory-controlled conditions using a concentration range of 10
-8 mol 1-1 to 10-3 mol 1-1 total dissolved Cu2+ , thus including environmentally relevant concentrations. Free Cu2+ concentrations were determined using an ion-selective electrode calibrated with a metal ion buffer. The phenotypic plasticity of S. acuminatus was measured as the number of cells per coenobia and found to be readily affected at low copper concentrations. Under healthy conditions (10-8 mol 1-1 total dissolved Cu2+ , 10-11 mol 1-1 free Cu2+ ) S. acuminatus formed eight-celled coenobia, whereas at 10-7 mol 1-1 total dissolved Cu2+ (3 × 10-10 mol 1-1 free Cu2+ ) these were absent and at 10-5 mol 1-1 total dissolved Cu2+ (5 × 10-8 mol 1-1 free Cu2+ ) free cells were predominant. Chlorophyll a synthesis was affected by 5 × 10-8 mol 1-1 free Cu-2+ or higher. EC50 (3.3 × 10-5 mol 1-1 free Cu2+ ) was obtained using chlorophyll a values after 96-h exposure to the toxicant. The number of cells per coenobia was a more sensitive parameter than chlorophyll a to assess Cu toxicity, and at concentrations that may be encountered in the environment. [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
- View/download PDF
43. STRUCTURE OF THE CAPSULAR AND EXTRACELLULAR POLYSACCHARIDES PRODUCED BY THE DESMID <em>SPONDYLOSIUM PANDURIFORME</em> (CHLOROPHYTA).
- Author
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Paulsen, Berit Smestad and Vieira, Armando Augusto Henriques
- Subjects
- *
PHARMACEUTICAL encapsulation , *CARBOHYDRATES , *GREEN algae , *POLYSACCHARIDES , *GLUCURONIC acid - Abstract
The filamentous desmid Spondylosium panduriforme (Heimerl) Teiling var. panduriforme f. limneticum (West & west) Teiling (Desmidiaceae)strain 072CH-UFCAR, is surrounded by a well-defined, mucilaginous capsule consisting of a capsular polysaccharide (CPS). This microalga also produces an extracellular polysaccharide. Analysis of the carbohydrate composition of the two polymers by gas chromatography showed that they were different. Both were composed of galactose fucose xylose, arabinose, rhamnose, and glucose but in different amounts. For example, glucuronic acid accounts for 24% of the EPS material but only traces were found in the CPS. Significant difference were also found during methylation analysis. Fucose appeared to have a higher degree of branching in the EPS than in the CPS. These branches were located on C-3 and could be the position for the attachment of the glucuronic acid was present as 1→ 4linked and terminal units. A possible explanation for the formation of the EPS is suggested. [ABSTRACT FROM AUTHOR]
- Published
- 1994
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44. The excretion of dissolved organic matter by natural phytoplankton populations in bioassays with nutrients
- Author
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Vieira, Armando Augusto Henriques and Teixeira, Clóvis
- Abstract
Foram efetuadas várias medidas de excreção de matéria orgânica dissolvida (MOD), utilizando-se populações naturais de fitoplâncton, provenientes da Enseada do Flamengo - litoral Norte do Estado de São Paulo - e enriquecidas artificialmente com nutrientes. A quantidade absoluta da MOD excretada, de um modo geral, acompanhou a quantidade de carbono total assimilado. Entretanto, nas populações com deficiência de nitrogênio, ocorreu um aumento das taxas relativas de excreção, não só devido à diminuição da assimilação total de carbono, mas, efetivamente, tambem ao aumento da quantidade absoluta de MOD excretada. Measurements of excreted dissolved organic matter (DOM) were carried out twice (in simmer and winter) using natural phytoplankton populations from "Enseada do Flamengo" (Lot. 23° 30'S-Long. 045°069'W) and enriched artificially with nutrients. The bioassays were carried out inoculating samples of an integral sea water in ten liters flasks, incubated "in situ". Measures were taken in populations growing in: integral " f " media, "f" - N, "f" - P, "f" - (H + P), "f" - (Vit. + Metal traces), and in a control without enrichment. The absolute amount of excreted DOM generally followed the quantity of total carbon assimilated. In the meantime, with the populations with nitrogen deficiency occurred an increase of relatives rates of excretion, not only due to the total carbon assimilation diminution, but effectively also to the absolute increase of the quantity of excreted DOM.
- Published
- 1982
45. Excreção de matéria orgânica dissolvida por populações fitoplanctônicas marinhas em bioensaios com nutrientes
- Author
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Vieira, Armando Augusto Henriques and Teixeira, Clóvis
- Abstract
Measurements of excreted dissolved organic matter (DOM) were carried out twice (in simmer and winter) using natural phytoplankton populations from "Enseada do Flamengo" (Lot. 23° 30'S-Long. 045°069'W) and enriched artificially with nutrients. The bioassays were carried out inoculating samples of an integral sea water in ten liters flasks, incubated "in situ". Measures were taken in populations growing in: integral " f " media, "f" - N, "f" - P, "f" - (H + P), "f" - (Vit. + Metal traces), and in a control without enrichment. The absolute amount of excreted DOM generally followed the quantity of total carbon assimilated. In the meantime, with the populations with nitrogen deficiency occurred an increase of relatives rates of excretion, not only due to the total carbon assimilation diminution, but effectively also to the absolute increase of the quantity of excreted DOM. Foram efetuadas várias medidas de excreção de matéria orgânica dissolvida (MOD), utilizando-se populações naturais de fitoplâncton, provenientes da Enseada do Flamengo - litoral Norte do Estado de São Paulo - e enriquecidas artificialmente com nutrientes. A quantidade absoluta da MOD excretada, de um modo geral, acompanhou a quantidade de carbono total assimilado. Entretanto, nas populações com deficiência de nitrogênio, ocorreu um aumento das taxas relativas de excreção, não só devido à diminuição da assimilação total de carbono, mas, efetivamente, tambem ao aumento da quantidade absoluta de MOD excretada.
- Published
- 1982
46. STRUCTURE OF EXTRACELLULAR POLYSACHARIDES PRODUCED BY A SOIL <em>CRYPTOMONAS</em> SP. (CRYPTOPHYCEAE).
- Author
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Paulsen, Berit Smestad, Vieira, Armando Augusto Henriques, and Klaveness, Dag
- Subjects
- *
POLYSACCHARIDES , *CYANOBACTERIA - Abstract
Examines the structure of extracellular polysaccharides produced by the Hindak strain of a soil Cryptomonas species. Presence of fucose, rhamnose, xylose, mannose, glucose, galactose, galacturonic acid, glucuronic acid, and traces of 3-O-methyl galactose; Degree of branching.
- Published
- 1992
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47. Effect of quality and complexity of phytoplanktonic dissolved organic matter on the diversity and activity of bacterial communities
- Author
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Moraes, Guilherme Pavan de, Vieira, Armando Augusto Henriques, and Bagatini, Inessa Lacativa
- Subjects
Cryopreservation ,Efeito-garrafa ,Matéria orgânica dissolvida ,Ambiente aquático ,Heterotrophic bacteria ,Bottle-effect ,Aquatic environment ,Comunidade bacteriana ,MICROBIOLOGIA [CIENCIAS BIOLOGICAS] ,Bactérias heterotróficas ,Criopreservação ,ECOLOGIA [CIENCIAS BIOLOGICAS] ,Dissolved organic matter ,Bacterial community ,MOD ,DOM - Abstract
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Bacteria are the world’s most abundant organisms and the foremost drivers of carbon and nutrient cycles in aquatic environments. Changes in the metabolic activity and composition of heterotrophic bacterial communities in response to interactions with dissolved organic matter (DOM) can potentially alter global biogeochemical cycles. In a context of global environmental changes, effects of the quantity and quality of DOM on the composition and activity of bacterial communities were investigated in experimental microcosms. Although such experiments allow a less descriptive analysis of these communities, they have limitations. Initial experimental communities need to be the same, limiting the number of manipulations that can be performed. Furthermore, microcosm cultivation usually results in drastic compositional changes in the communities. Thus, we also evaluated a cryopreservation method for whole natural communities which allows experiments with a unique initial community to be performed separately, as well as the effects of varying DOMs to keep the diversity of the cryopreserved communities. The results showed that both DOM quantity and quality were related to changes in the communities, with quality exerting an early response effect driven by competition and the intensity and duration of the effect modulated by quantity. Moreover, diversity and community composition of the bacterial communities were generally maintained after cryopreservation, although part of the diversity was lost, something more evident for communities from more stable and oligotrophic environments. In a global warming context, increase in the temperature oceans and freshwater bodies are expected, which could cause changes in the quantity and quality of the available DOM within these environments. This outcome could alter composition and metabolism of heterotrophic bacterial communities, causing not fully understood impacts on the carbon and nutrients global cycles. Bactérias são os organismos mais abundantes e a principal força motriz para o ciclo de carbono e de nutrientes em ambientes aquáticos. Variações na atividade metabólica e composição das comunidades bacterianas heterotróficas que resultam das interações com matéria orgânica dissolvida (MOD) têm capacidade de alterar ciclos biogeoquímicos globais. Considerando um contexto de mudanças ambientais globais, o efeito da quantidade e qualidade da MOD na composição e atividade das comunidades bacterianas foi avaliado em experimentos em microcosmos. Embora permitam ir além de uma análise puramente descritiva das comunidades microbianas e realizar manipulações, experimentos em meso e microcosmos têm limitações. Estes experimentos necessitam iniciar com a mesma comunidade, o que limita o número de manipulações concomitantes possíveis. Além disso, cultivos em microcosmo normalmente resultam em mudanças drásticas na composição das comunidades. Assim, um método de criopreservação de comunidades bacterianas naturais completas, que permita a estocagem e utilização em diferentes tempos de uma mesma comunidade inicial, foi avaliado, bem como o efeito de diferentes MODs sobre a manutenção da diversidade nessas comunidades cultivadas após criopreservação. Os resultados mostraram que tanto quantidade quanto qualidade de MOD correlacionaram-se com mudanças na comunidade bacteriana, mas a qualidade exerceu um efeito rápido por competição, com sua intensidade e duração moduladas pela quantidade. No geral, também foi possível manter a diversidade e composição de comunidades bacterianas naturais após criopreservação, embora uma fração da diversidade seja perdida, especialmente em comunidades oriundas de ambientes mais estáveis e oligotróficos. Isto é problemático pois se espera que em um contexto de aquecimento global a temperatura dos oceanos e corpos d’água doce aumentem, algo que poderia levar a mudanças na quantidade e qualidade da MOD destes ambientes. Isto potencialmente alteraria a composição e metabolismo das comunidades bacterianas heterotróficas, causando impactos nos ciclos globais do carbono e nutrientes que ainda não são completamente compreendidos. CAPES: código de financiamento - 001
- Published
- 2019
48. Biodiversity and patterns of co-occurrence between phytoplankton and bacteria in the trophic cascade of Tiete river reservoirs: an approach with High Throughput Sequencing
- Author
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Vieira, Helena Henriques, Vieira, Armando Augusto Henriques, and Bagatini, Inessa Lacativa
- Subjects
Reservatórios ,Reservatorios tropicais ,Tropical reservoirs ,Trophic state gradient ,MICROBIOLOGIA::BIOLOGIA E FISIOLOGIA DOS MICROORGANISMOS::BACTEROLOGIA [CIENCIAS BIOLOGICAS] ,Metacomunidade microbiana aquática ,Cascading reservoirs ,MICROBIOLOGIA [CIENCIAS BIOLOGICAS] ,Reservoirs ,CIENCIAS BIOLOGICAS ,Ecological networks ,Redes ecológicas ,Freshwater bacterioplankton metacomunity ,ECOLOGIA [CIENCIAS BIOLOGICAS] ,Reservatórios em cascata ,Gradiente de estado trófico - Abstract
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Microbial communities of aquatic environments make up a complex ecological network where organisms interact with each other and with the environment. The way these microbial communities are structured is influenced by abiotic factors such as temperature, pH, nutrient availability, etc., since the different taxa of organisms respond differently to environmental factors. Cascade arrangement generates limnological properties beyond those often reported for lentic systems. Greater mixing of water, that generates greater water turbidity in upstream reservoirs, nutrient pulses, and introduction of organisms from the previous reservoirs and the adjacencies of each reservoir are characteristic of cascade systems. Dry and rainy seasons should modulate such attributes through the amount of water that connects the reservoirs, so that the rainy season promotes greater upstream transport of water from the downstream due to the shorter residence time, as well as greater introduction of allochthonous material. The opposite is expected in the dry season, where the lower flow of water between the reservoirs increases the residence time of the reservoirs allowing the organisms to remain for a longer period in the reservoirs. In this study, we explored the composition of the microbial community of four cascading reservoirs of the medium-low Tietê River as well as the factors that governed microorganism’s turnover along the cascade in the dry and rainy periods. Finally, we analyzed the effect of the trophic gradient on the ecological networks of the microbial communities of each reservoir. We found that the cascade formation of these reservoirs influenced the structure of the microbial communities so that each subcommunity (bacteria attached to particles or free-living, cyanobacteria and eukaryotic phytoplankton) studied responded to different environmental factors that varied along the cascade or seasons. In the same way, the variation in subcommunity structures along the waterfall was guided by both local factors (local environmental conditions of each reservoir, promoting selection) and regional (dispersion of organisms), but with regional factors predominating. Finally, we observed the influence of the trophic gradient on the ecological networks of microbial interactions: highly eutrophic environments, by constricting the diversity, especially of primary producers, produce networks with high modularity, that is, subgroups interacting less inserted the global network. With the eutrophication reduction we observed more connected networks, with less modularity, where subgroups are immersed in the global network of the community. As comunidades microbianas de ambientes aquáticos compõem uma complexa rede ecológica onde organismos interagem entre si e com o ambiente. A maneira como estas comunidades microbianas estão estruturadas está sob influência de fatores abióticos como temperatura, pH, disponibilidade de nutrientes, entre outros, visto que os diversos taxa de organismos respondem de maneira diferente aos fatores ambientais. A disposição em cascata de reservatórios gera propriedades limnológicas além das frequentemente relatadas para sistemas lênticos. Maior mistura de água gera maior turbidez da água nos reservatórios a montante, pulsos de nutrientes e introdução de organismos proveniente dos reservatórios anteriores e das adjacências de cada reservatório são característicos de sistemas em cascata. Estações de seca e de chuva devem modular tais atributos através da quantidade de água que conecta os reservatórios, de maneira que a estação chuvosa promove maior transporte de água da montante à jusante, devido ao menor tempo de residência, além de maior introdução de material alóctone. O contrário é esperado na estação de seca, onde o menor fluxo de água entre os reservatórios aumenta o tempo de residência dos reservatórios permitindo que os organismos que ali se encontrem permaneçam por período mais longo nos reservatórios. Neste estudo, exploramos a composição da comunidade microbiana de quatro reservatórios em cascata do médio-baixo Tietê assim como os fatores que regeram a migração dos microrganismos ao longo da cascata nos períodos de seca e de chuva. Por fim, analisamos o efeito do gradiente trófico nas redes ecológicas das comunidades microbianas de cada reservatório. Nós encontramos que a formação em cascata destes reservatórios influenciou a estrutura das comunidades microbianas de maneira que cada subcomunidade (bactérias aderidas a partículas, de vida livre, cianobactérias e fitoplâncton eucariótico) estudada respondeu a diferentes fatores ambientais que variaram ao longo da cascata ou de estações. Da mesma maneira, a variação nas estruturas das subcomunidade ao longo da cascata foi guiada tanto por fatores locais (condições ambientais local de cada reservatório), que promovem seleção, por fatores regionais (dispersão dos orgaismos), entretanto com predominância dos fatores regionais. Finalmente, observamos a influência do gradiente trófico nas redes ecológicas de interações microbianas: ambientes altamente eutrofizados, por constringir a diversidade especialmente de produtores primários, produz redes com alta modularidade, ou seja, subgrupos interagindo de maneira menos inserida da rede global. Já com a redução da eutrofização observamos redes mais conectadas, com menor modularidade, onde subgrupos encontram-se imersos na rede global da comunidade CAPES BEX: 88881.132338/2016-01
- Published
- 2019
49. Oxylipins in the study of the biodiversity of freshwater microalgae
- Author
-
Moreira, Ingritt Caroline and Vieira, Armando Augusto Henriques
- Subjects
Charophyta ,BIOQUIMICA::BIOQUIMICA DOS MICROORGANISMOS [CIENCIAS BIOLOGICAS] ,Selenastraceae ,Oxo-acids ,Hidroxi-ácidos ,Hydroxy-acids ,BOTANICA::TAXONOMIA VEGETAL [CIENCIAS BIOLOGICAS] ,Oxilipinas ,BOTANICA [CIENCIAS BIOLOGICAS] ,BOTANICA::BOTANICA APLICADA [CIENCIAS BIOLOGICAS] ,MICROBIOLOGIA [CIENCIAS BIOLOGICAS] ,Chlorophyta ,Oxo-ácidos ,Oxylipins - Abstract
Outra Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This research focuses on the oxylipins with eighteen carbons, compound derived of polyunsaturated fatty acids, produced by twenty-two species of freshwater algae, one cyanobacteria and three species of plants, with emphasis on green microalgae from the Chlorophyta and Charophyta phylum, and also species of the Selenastraceae family (Chlorophyta, Chlorophyceae, Sphaeropleales). The aim was detected, identified and quantified oxylipins derived from linoleic and linolenic acids produced by microorganisms using High-Performance Liquid Chromatography coupled tandem Mass Spectrometry technique. It was used microalgae from the Culture Collection of Freshwater Microalgae (CCMA-UFSCar), species already classified by classic and / or molecular taxonomy, as well as the species of plants for comparative purposes. For the experiments, the material came from the end of stationary phase. Once the compounds were identified by these techniques, it was tested the possibility of using profiles as diacritical characteristics in a chemotaxonomic approach for formation of hierarchical clusters. The pharmacological potential of these compounds was discussed since they present antibiotic and anti-inflammatory activities. Other possible commercial applications were approached since microalgae revealed their potential value as natural sources of hydroxy fatty acids. No oxylipin was exclusively observed to determinated organism that could represents as species indicator. This condition limits the use of oxylipins derived from C18 PUFAs in the taxonomy of the Selenastraceae family, but even so, these compounds provide complementary information for organisms that may be useful in their identification. There was universality regarding the presence of oxylipins analysed in all the taxonomic groups studied. The strains belonging to Chlorophyta division showed the highest total concentrations of oxylipins. Charophyta algae have a concentration of oxylipins dozens of times lower than Chlorophyta, and similar to concentrations found in plants, which may be related to the evolutionary proximity among plants and Charophyta. Esta pesquisa tem como foco oxilipinas com dezoito carbonos, substâncias derivadas de ácidos graxos poli-insaturados, produzidas por vinte e duas cepas de algas de água doce, uma cianobactéria e três espécies de plantas, com ênfase em microalgas verdes das divisões Chlorophyta e Charophyta, e também em espécies da família Selenastraceae (Chlorophyta, Chlorophyceae, Sphaeropleales). O objetivo principal foi detectar, identificar e quantificar as oxilipinas derivadas de ácidos linoléico e linolênico produzidas por esses organismos utilizando-se de técnicas de cromatografia líquida acoplada à espectrometria de massas. Utilizou-se cepas de microalgas da coleção de culturas do Laboratório de Ficologia da UFSCar, espécies já classificadas através da taxonomia clássica e/ou molecular, como também espécies de plantas para fins comparativos. Para os experimentos, a biomassa algal foi proveniente do final da fase estacionária. Uma vez identificados estes compostos pelas técnicas acima, testou-se a possibilidade de se utilizar estes perfis como características diacríticas em uma abordagem quimiotaxonômica para a formação de clusters hierárquicos. Também foi discutido o potencial farmacológico destes compostos por apresentarem atividades antibióticas e anti-inflamatórias. Outras possíveis aplicações comerciais também foram abordadas uma vez que as microalgas revelaram seu potencial valor como reservas naturais de hidroxi-ácidos. Não foi observada qualquer oxilipina exclusiva para determinado organismo que pudesse servir como um indicador de espécie. Esta condição limita a utilização de oxilipinas derivadas de PUFAs C18 na taxonomia da família Selenastraceae. Porém, mesmo assim, a quantidade e proporções das oxilipinas nos diversos perfis permitem que estes compostos forneçam informações complementares sobre os organismos que podem ser uteis na sua identificação. Houve universalidade quanto à presença das oxilipinas analisadas em todos os grupos taxonômicos estudados. As cepas pertencentes à divisão Chlorophyta apresentaram as maiores concentrações totais de oxilipinas. As algas Charophyta apresentaram concentrações de oxilipinas dezenas de vezes menor que Chlorophyta e semelhantes às concentrações encontradas em plantas, fato que pode estar relacionado à proximidade evolutiva entre plantas e Charophyta. CNPQ: 141267/2014-3 FAPESP: 2011/50054-4
- Published
- 2018
50. Conservação de bio-recursos algais no Brasil: estabelecimento de um banco criopreservado
- Author
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Tessarolli, Letícia Piton, Vieira, Armando Augusto Henriques, and Day, John Godfrey
- Subjects
Conservação da natureza ,Nature conservation ,Algas de água doce ,ECOLOGIA [CIENCIAS BIOLOGICAS] ,Freshwater algae - Abstract
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The establishment of culture collections is a vital aspect for the conservation freshwater microalgae, which are a very diverse group of organisms with important ecological functions on the ecosystems maintenance and an immense although still sparsely explored biotechnological potential, particularly for the use of metabolites and biodiesel production. The traditional protocol for culture maintenance is the serial subculturing of metabollicaly active cultures. Although strains have been maintained in metabolically active cultures for decades, there are several reports of loss of characteristics for the organisms thus maintained, and an increase in the number of strains could be the cause for logistical challenges on the maintenance regimes and elevated costs with material and functionalism. Cryopreservation, which is the maintenance of organisms at ultra-low temperatures to the point that all cellular metabolic functions are paused, appears as a recommended alternative for the maintenance of long-term culture collections. The use of this technique allows the maintenance of samples for long periods of time with minimal handling, severely reducing the maintenance costs, while maintaining the stability of cultures, which should be stored at ultra-low temperatures to eliminate the occurrence of intracellular chemical processes. The Freshwater Microalgae Culture Collection (CCMA-UFSCar) currently maintains approximately 700 microalgae strains in metabolically active cultures, which is reaching maximum support capacity for routine maintenance practices. The requirements with cultures maintenance will also, consequently, affect the provision services of the collection, which are the basis of research of a large number of projects throughout Brazil. Thus, the main objective of this project was to test the feasibility of the use of cryopreservation as a technique to maintain algal cultures in this culture collection. For this, initially positive results were obtained for the application of a standard freezing protocol, particularly for green coccoid algae. However, larger and more complex organisms are still recalcitrant to freezing, with low rates of recovery, which will require further research and adaptation of the protocols to meet the particularities of each strain. In parallel to the establishment of the cryopreserved biobank for CCMA-UFSCar, projects were developed in order to further clarify details and consequences of the process of freezing and storing organisms at low temperatures, seeking to improve the success rates for the implementation of this technique. The effects of the presence of contaminating organisms on the microalgae cultures on the response of strains to freezing, and consequently on the formation of viable and robust post-thaw cultures, were verified a few selected non-axenic strains. It was noticed that the choice of cryoprotectant solution (CPA), used to protect cells during freezing, may be crucial for post-thaw recovery, and it is necessary to search for balance between obtaining the highest possible viability levels and avoiding the extreme proliferation of contaminating organisms, which could lead to inhibition in the recovery and quality of the desired algal cultures after the process. In addition to direct survival to the freezing process, which is a potentially damaging for cells, the longevity of samples maintained at different temperatures was also tested, aiming to establish the simplest and most cost-effective procedure to ensure the long term survival of frozen samples. It was observed that the storage temperatures, as well as the CPA used during freezing, were significant aspects to guarantee the continued viability of the frozen cultures, and only samples maintained immersed in liquid nitrogen were sufficiently protected against temperature fluctuations, ensuring the survival of all the samples for longer periods. Furthermore, the continuity of the viability for samples maintained immersed in liquid nitrogen was also observed in a study with samples maintained on these conditions for up to 40 years at Culture Collection of Algae and Protozoa (CCAP, UK). The freezing process per se is potentially damaging to the cultures during the process, which might be the cause for functional and genetic differences in cells that have undergone this process. Thus, biochemical and genetic analysis were used to verify the stability of the cultures submitted to the freezing protocol. To ensure the successful implementation of a cryopreserved microalgae bank for CCMA-UFSCar, in addition to viability and stability measures, it is necessary to establish protocols for sample management and routine maintenance. Thus, a case study was carried out with the experiences acquired in CCAP during the 40 years of the history of a cryopreserved bank, and how the application of these techniques can benefit the quality control and management of CCMA-UFSCar, facilitating the implementation of the cryopreserved biobank for this culture collection. O estabelecimento de uma coleção de culturas é um passo crucial na conservação de microalgas de água-doce, que é um grupo bastante diverso de organismos que desempenha importantes funções e com vasto potencial para a exploração biotecnológica, particularmente na utilização de metabólitos secundários e produção de biodiesel. O método mais tradicional para manutenção de microalgas é a utilização de culturas metabolicamente ativas. Embora coleções venham sendo assim mantidas há décadas, existem relatos de perdas de características dos organismos. Além disso, essa técnica de manutenção limita o crescimento das coleções, devido aos elevados custos com material e funcionalismo, assim como limitações espaciais. A criopreservação, que é a manutenção de organismos em temperaturas ultra-baixas a ponto de que todas as funções metabólicas celulares sejam pausadas, surge, então, como uma alternativa recomendada para a manutenção de coleções de culturas em longo termo. O uso dessa técnica permite que amostras sejam mantidas por longos períodos de tempo com mínimo manuseio, consequentemente reduzindo os custos de manutenção, enquanto mantém a estabilidade de culturas, já que as temperaturas são baixas o suficiente para eliminar a ocorrência de processos químicos intracelulares. A Coleção de Culturas de Microalgas de Água-doce (CCMA-UFSCar) mantém atualmente cerca de 700 linhagens de microalgas em culturas metabolicamente ativas, número que está alcançando a capacidade suporte para as práticas rotineiras de manutenção, consequentemente limitando também a provisão de culturas, que beneficiam um grande número de laboratórios pelo Brasil. Assim, esse projeto teve como principal objetivo, estudar a viabilidade da utilização da criopreservação como técnica para manutenção de culturas algais nessa coleção. Inicialmente foram obtidos resultados positivos para a aplicação de um protocolo usual de congelamento, particularmente para algas verdes cocóides. Entretanto, organismos maiores e mais complexos ainda apresentam certa resistência ao congelamento, com baixas taxas de recuperação dos organismos, o que pode exigir testes mais aprofundados e adaptação nos protocolos para atender as particularidades de cada cepa. Em paralelo ao estabelecimento do banco criopreservado de microalgas da CCMA-UFSCar, foram desenvolvidos projetos para estudar alguns detalhes do processo de congelamento e armazenamento de organismos em baixas temperaturas, buscando aprimorar o sucesso da implementação dessa técnica. Os efeitos da presença de organismos contaminantes nas culturas de microalgas na resposta das culturas ao congelamento, e consequentemente na obtenção de culturas viáveis para futuras aplicações, foram verificados para selecionadas culturas unialgais. Foi possível observar que, para a manutenção de culturas não-axênicas, a escolha da solução crioprotetora (CPA), utilizada para proteção das células durante o congelamento, pode ser crucial na recuperação das culturas, já que é preciso encontrar um balanço entre a melhor proteção para células algais enquanto deve ser evitada a proliferação extrema dos organismos contaminantes, o que pode inibir o crescimento das cepas desejadas após o processo. Além da sobrevivência direta ao processo de congelamento, já que esse é um processo potencialmente danoso para as células, também foi testada a longevidade de amostras mantidas em diferentes temperaturas, buscando estabelecer o procedimento mais simples e com melhor custo-benefício para a coleção, enquanto mantém a estabilidade das culturas. As temperaturas de manutenção das amostras, assim como o CPA utilizado durante o congelamento, foram significativas para a continuidade da viabilidade das culturas congeladas, e somente a manutenção das amostras imersas em nitrogênio líquido foi suficiente para garantir a sobrevivência de todas as amostras por um período de um ano. Além disso, a continuidade da viabilidade das amostras mantidas imersas em nitrogênio líquido foi observada também para amostras mantidas por até 40 anos, na Culture Collection of Algae and Protozoa (CCAP), localizada no Reino Unido. O processo de congelamento per se é potencialmente danoso para as culturas a ele submetidas, o que pode vir a causar diferenças em funcionalidade e genéticas nas células que foram submetidas a esse processo. Assim, análises bioquímicas e genéticas foram utilizadas para verificar a estabilidade das culturas submetidas a esse processo. Para garantir o sucesso da implementação de um banco criopreservado de microalgas para a CCMA-UFSCar, além das medidas de viabilidade e estabilidade, é necessário estabelecer protocolos de gerenciamento das amostras e manutenção de rotina. Assim, foi realizado um estudo de caso contando com as experiências adquiridas na CCAP durante 40 anos de história de um banco criopreservado, e como a aplicação dessas técnicas podem beneficiar o controle de qualidade e gerenciamento da CCMA-UFSCar, facilitando a implementação do biobanco criopreservado para essa coleção. FAPESP: 2014/23605-8 FAPESP: 2011/50054-4
- Published
- 2016
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