Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Biotechnol Adv ; 25(2): 176-94, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17208406

RESUMO

Dinoflagellates are microalgae that are associated with the production of many marine toxins. These toxins poison fish, other wildlife and humans. Dinoflagellate-associated human poisonings include paralytic shellfish poisoning, diarrhetic shellfish poisoning, neurotoxic shellfish poisoning, and ciguatera fish poisoning. Dinoflagellate toxins and bioactives are of increasing interest because of their commercial impact, influence on safety of seafood, and potential medical and other applications. This review discusses biotechnological methods of identifying toxic dinoflagellates and detecting their toxins. Potential applications of the toxins are discussed. A lack of sufficient quantities of toxins for investigational purposes remains a significant limitation. Producing quantities of dinoflagellate bioactives requires an ability to mass culture them. Considerations relating to bioreactor culture of generally fragile and slow-growing dinoflagellates are discussed. Production and processing of dinoflagellates to extract bioactives, require attention to biosafety considerations as outlined in this review.


Assuntos
Biotecnologia/métodos , Dinoflagellida , Análise de Alimentos/métodos , Toxinas Marinhas/análise , Animais , Reatores Biológicos , Biotecnologia/instrumentação , Ciguatera/diagnóstico , Diarreia/induzido quimicamente , Dinoflagellida/classificação , Dinoflagellida/metabolismo , Dinoflagellida/fisiologia , Análise de Alimentos/normas , Doenças Transmitidas por Alimentos/diagnóstico , Humanos , Toxinas Marinhas/toxicidade , Paralisia/induzido quimicamente , Padrões de Referência
2.
Bioprocess Biosyst Eng ; 28(4): 243-50, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16247611

RESUMO

The effect of mechanical agitation on the microalgae Phaeodactylum tricornutum and Porphyridium cruentum was investigated in aerated continuous cultures with and without the added shear protectant Pluronic F68. Damage to cells was quantified through a decrease in the steady state concentration of the biomass in the photobioreactor. For a given aeration rate, the steady state biomass concentration rose with increasing rate of mechanical agitation until an upper limit on agitation speed was reached. This maximum tolerable agitation speed depended on the microalgal species. Further increase in agitation speed caused a decline in the steady state concentration of the biomass. An impeller tip speed of >1.56 m s(-1) damaged P. tricornutum in aerated culture. In contrast, the damage threshold tip speed for P. cruentum was between 2.45 and 2.89 m s(-1). Mechanical agitation was not the direct cause of cell damage. Damage occurred because of the rupture of small gas bubbles at the surface of the culture, but mechanical agitation was instrumental in generating the bubbles that ultimately damaged the cells. Pluronic F68 protected the cells against damage and increased the steady state concentration of the biomass relative to operation without the additive. The protective effect of Pluronic was concentration-dependent over the concentration range of 0.01-0.10% w/v.


Assuntos
Reatores Biológicos/microbiologia , Diatomáceas/citologia , Diatomáceas/fisiologia , Estimulação Física/métodos , Poloxâmero/administração & dosagem , Porphyridium/citologia , Porphyridium/fisiologia , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Eucariotos/citologia , Eucariotos/fisiologia , Especificidade da Espécie
3.
Biotechnol Bioeng ; 81(4): 459-73, 2003 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-12491531

RESUMO

A dynamic model of photosynthesis is developed, accounting for factors such as photoadaptation, photoinhibition, and the "flashing light effect." The model is shown to explain the reported photosynthesis-irradiance responses observed under various conditions (constant low light, constant intense irradiance, flashing light, diurnal variation in irradiance). As significant distinguishing features, the model assumes: (1) The stored photochemical energy is consumed in an enzyme-mediated process that obeys Michaelis-Menten kinetics; and (2) photoinhibition has a square-root dependence on irradiance. Earlier dynamic models of photosynthesis assumed a first-order dependence of photoinhibition on irradiance and different kinetics of consumption of the stored energy than used in this work. These earlier models could not explain the photosynthesis-irradiance behavior under the full range of irradiance scenarios-a shortcoming that is overcome in the model developed in this work.


Assuntos
Simulação por Computador , Modelos Biológicos , Fotossíntese/fisiologia , Fitoplâncton/fisiologia , Fitoplâncton/efeitos da radiação , Adaptação Biológica/fisiologia , Ritmo Circadiano/fisiologia , Escuridão , Luz , Modelos Químicos , Dinâmica não Linear , Estimulação Luminosa , Fotoperíodo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA