Ação alelopática de saxitoxinas e microcistinas em cianobactérias e microalgas verdes em condições controladas
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Data
2013-02-21
Autores
Camargo-Santos, Danilo [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A alelopatia é definida como um efeito prejudicial ou benéfico provocado por substâncias produzidas por microrganismos ou plantas sobre fungos, plantas, bactérias ou algas. Muitos trabalhos sugerem que cianotoxinas provocam efeitos alelopáticos em organismos fitoplanctônicos. Todavia, muitos estudos utilizaram concentrações de toxinas superiores àquelas normalmente encontradas nos ecossistemas aquáticos (>10μg.L-1), por isso nossa hipótese é que, em baixas concentrações, cianotoxinas não provocam efeitos alelopáticos. Esse estudo visa avaliar os possíveis efeitos alelopáticos das saxitoxinas (SX) nas densidades celulares das linhagens de microalgas verdes Monoraphidium convolutum (Corda) Komárková-Legnerová CMEA/UFF0201 e Scenedesmus acuminatus (Lagerheim) Chodat UFSCar036, e das cianobactérias Microcystis wesenbergii (Komárek) Komárek BCCUSP11 e Microcystis aeruginosa (Kützing) Kützing BCCUSP232, assim como os de microcistinas (MC) na densidade celular das linhagens M. wesenbergii BCCUSP11 e M. aeruginosa BCCUSP232, em quatro diferentes concentrações até 10μg.L-1. Seis experimentos, com 14 dias de duração, foram realizados em câmaras com condições controladas de temperatura (24± 1°C), fotoperíodo (14:10h claro:escuro) e luz (40μmol.m-2.s-1). O controle e os tratamentos foram treplicados e realizados em meio de cultura ASM-1 (pH 7,4), com densidade celular inicial de 1,0 x 105 cel.mL-1. Os extratos brutos com presença e ausência de SX (SX+ e SX-) ou MC (MC+ e MC-), provenientes de Cylindrospermopsis raciborskii (Woloszinska) Seenayya & Raju e de M. aeruginosa, respectivamente, foram adicionados nos cultivos dos tratamentos 0.5, 1.0, 5.0 e 10.0 SX ou MC μg.L-1 de toxina no 4º dia. Não foi adicionado qualquer extrato aos controles. Foram obtidas as...
Allelopathy is defined as stimulating or inhibitory effect caused by substances produced by plants or microorganisms in fungus, plant, bacteria or algae. Cyanotoxins seem to induce allelopathical effects in phytoplanktonic organisms, as is suggested by some studies. However, these studies were performed with high toxins concentrations, which are higher than normally is reported for aquatic ecosystems (>10μg.L-1). We hypothesize that, under low concentrations, cyanotoxins do not cause allelopathical effects. This study aimed to evaluate the possible allelopathical effects of saxitoxins (SX) in the cell density of four target strains: the green algae Monoraphidium convolutum (Corda) Komárková-Legnerová CMEA/UFF0201 and Scenedesmus acuminatus (Lagerheim) Chodat UFSCar036, the cyanobacterium Microcystis wesenbergii (Komárek) Komárek BCCUSP11 and Microcystis aeruginosa (Kützing) Kützing BCCUSP232. We also aimed to evaluate the allelopathical effects of the microcystins (MC) in the cell density of two cyanobacterium target strain, Microcystis wesenbergii (Komárek) Komárek BCCUSP11 and Microcystis aeruginosa (Kützing) Kützing BCCUSP232, by using four different concentrations up to 10μg.L-1. Each of the six experiments last 14 days and were performed in incubation chambers with controlled temperature (24± 1°C), photoperiod (14:10h light:dark) and light intensity (40μmol.m-2.s-1). The control treatment and all the others were triplicated with initial cell density of 1,0 x 105 cel.mL-1, cultivated in ASM-1 medium (pH 7,4). The crude extracts with and without SX (SX+ or SX-) or MC (MC+ or MC-), obtained from Cylindrospermopsis raciborskii (Woloszinska) Seenayya & Raju and M. aeruginosa, respectively, were added to the treatments cultures on the 4th day, using the following toxin concentrations:... (Complete abstract click electronic access below)
Allelopathy is defined as stimulating or inhibitory effect caused by substances produced by plants or microorganisms in fungus, plant, bacteria or algae. Cyanotoxins seem to induce allelopathical effects in phytoplanktonic organisms, as is suggested by some studies. However, these studies were performed with high toxins concentrations, which are higher than normally is reported for aquatic ecosystems (>10μg.L-1). We hypothesize that, under low concentrations, cyanotoxins do not cause allelopathical effects. This study aimed to evaluate the possible allelopathical effects of saxitoxins (SX) in the cell density of four target strains: the green algae Monoraphidium convolutum (Corda) Komárková-Legnerová CMEA/UFF0201 and Scenedesmus acuminatus (Lagerheim) Chodat UFSCar036, the cyanobacterium Microcystis wesenbergii (Komárek) Komárek BCCUSP11 and Microcystis aeruginosa (Kützing) Kützing BCCUSP232. We also aimed to evaluate the allelopathical effects of the microcystins (MC) in the cell density of two cyanobacterium target strain, Microcystis wesenbergii (Komárek) Komárek BCCUSP11 and Microcystis aeruginosa (Kützing) Kützing BCCUSP232, by using four different concentrations up to 10μg.L-1. Each of the six experiments last 14 days and were performed in incubation chambers with controlled temperature (24± 1°C), photoperiod (14:10h light:dark) and light intensity (40μmol.m-2.s-1). The control treatment and all the others were triplicated with initial cell density of 1,0 x 105 cel.mL-1, cultivated in ASM-1 medium (pH 7,4). The crude extracts with and without SX (SX+ or SX-) or MC (MC+ or MC-), obtained from Cylindrospermopsis raciborskii (Woloszinska) Seenayya & Raju and M. aeruginosa, respectively, were added to the treatments cultures on the 4th day, using the following toxin concentrations:... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Plant physiology, Fisiologia vegetal, Alelopatia, Toxinas, Fitoplâncton, Cianobacteria, Microcistinas, Saxitoxinas
Como citar
CAMARGO-SANTOS, Danilo. Ação alelopática de saxitoxinas e microcistinas em cianobactérias e microalgas verdes em condições controladas. 2013. 95 f. Dissertação - (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Biociências de Rio Claro, 2013.