Hierarquização da eficiência de remoção de cianotoxinas por meio de adsorção em carvão ativado granular / Evaluation of hierarchy of cyanotoxin removal by adsorption onto granular activated carbon

RESUMO O trabalho objetivou avaliar a remoção concomitante de duas cianotoxinas - microcistina-LR e saxitoxina-STX - por meio da adsorção em carvão ativado granular. Em primeira etapa, três carvões de granulometrias distintas, dois de coco de dendê e um mineral, foram avaliados na adsorção de microcistina-LR em água destilada e tratada com concentrações de 3,9 a 9,4 ug.L-1. O carvão de coco de dendê de menor granulometria apresentou desempenho mais uniforme, tanto no que tange à remoção (%) de microcistina-LR, quanto ao volume de efluente produzido consoante com as recomendações do padrão de potabilidade brasileiro. Em segunda etapa, apenas para o carvão selecionado na etapa precedente, concentrações de microcistina-LR e saxitoxina-STX aproximadamente 50% superiores dos limites do mesmo padrão de potabilidade foram dispersas em água destilada. Tais ensaios de adsorção evidenciaram que apenas a adsorção de saxitonina não foi influenciada pela simultaneidade das duas cianotoxinas.

ABSTRACT This study focused on the simultaneous removal of two cyanotoxins - microcystin-LR and saxitoxin-STX - by means of adsorption onto granular activated carbon. In first step, three carbons with different granulometry (dende coconut and mineral) were evaluated on adsorption of microcystin-LR in distilled and treated waters in concentrations at about 3.9 to 9.4 ug.L-1. The dende coconut carbon with lower granulometry showed higher performance according to the limits established by Brazilian Drinking Water Standards. In second step, with the selected carbon in previous step, concentrations of the two cyanotoxins 50% higher than those limits were dispersed in distilled water. The tests pointed out that only saxitoxin-STX removal was not affect by the presence both cyanotoxins.

Research Progress of Binding Targets of Saxitoxin / 中国生化药物杂志

Saxitoxin (STX) is one of the most toxic marine toxins.Scientists have been focusing on STX research due to the potentially pharmaceutical values and serious threat to human safety and health.. This review summarizes the structure, properties, binding targets and combination of structural basis of STX and its analogues in recent years reported. STX can bind Na+, K+, Ca2+channels to suppress the channel ion current, but also combine the bullfrog Saxiphilin protein and puffer fish STX/TTX binding protein (PSTBP) to protect the body from STX toxicity. STX also as a substrate for STX enzymes and affects the activity of nitric oxide synthase, antioxidant enzymes. Furthermore,this review has a comprehensive analysis of these targets of STX and a preliminary discussion of the medicinal value of anesthesia and analgesia and the development of antidotes to STX. It is expected to provide a reference for further study of the nature of STX and its application in various fields.

Behavioral alterations induced by repeated saxitoxin exposure in drinking water

Blooms of the saxitoxin-producing cyanobacterium Cylindrospermopsis raciborskii have been contaminating drinking water reservoirs in Brazil for many years. Although acute effects of saxitoxin intoxication are well known, chronic deleterious outcomes caused by repeated saxitoxin exposure still require further investigation. The aim of the present work is to investigate the effects of consumption of drinking water contaminated with C. raciborskii for 30 days on learning and memory processes in rats. Methods The effects of saxitoxin (3 or 9 g/L STX equivalents) or cyanobacteria on behavior was determined using the open field habituation task, elevated plus maze anxiety model task, inhibitory avoidance task, and referential Morris water maze task. Results No effects of saxitoxin consumption was observed on anxiety and motor exploratory parameters in the elevated plus maze and open field habituation tasks, respectively. However, groups treated with 9 g/L STX equivalents displayed a decreased memory performance in the inhibitory avoidance and Morris water maze tasks. Conclusions These results suggest an amnesic effect of saxitoxin on aversive and spatial memories.

Behavioral alterations induced by repeated saxitoxin exposure in drinking water

Background: Blooms of the saxitoxin-producing cyanobacterium Cylindrospermopsis raciborskii have been contaminating drinking water reservoirs in Brazil for many years. Although acute effects of saxitoxin intoxication are well known, chronic deleterious outcomes caused by repeated saxitoxin exposure still require further investigation. The aim of the present work is to investigate the effects of consumption of drinking water contaminated with C. raciborskii for 30 days on learning and memory processes in rats. Methods: The effects of saxitoxin (3 or 9 µg/L STX equivalents) or cyanobacteria on behavior was determined using the open field habituation task, elevated plus maze anxiety model task, inhibitory avoidance task, and referential Morris water maze task. Results: No effects of saxitoxin consumption was observed on anxiety and motor exploratory parameters in the elevated plus maze and open field habituation tasks, respectively. However, groups treated with 9 µg/L STX equivalents displayed a decreased memory performance in the inhibitory avoidance and Morris water maze tasks. Conclusions: These results suggest an amnesic effect of saxitoxin on aversive and spatial memories.(AU)

Effects of Cylindrospermopsis raciborskii strains (Woloszynska, 1912) Senayya & Subba Raju on the mobility of Daphnia laevis (Cladocera, Daphniidae) / Efeitos de cepas de Cylindrospermopsis raciborskii (Woloszynska, 1912), Senayya & Subba Raju na mobilidade de Daphnia laevis (Cladocera, Daphniidae)

Cylindrospermopsis raciborskii is a cyanobacterium distributed worldwide that is known to produce cyanotoxins. Some of the Brazilian strains can produce saxitoxins (STXs), which are classified as neurotoxins and can paralyze cladocerans .Daphnia laevis is a cladoceran with a wide distribution in the Americas and has been studied as a possible test-organism in toxicity bioassays. The present work tested the acute effect on D laevis mobility when fed a saxitoxin-producing (STX and neoSTX) C. raciborskii strain, CYRF-01, and compared the results with the effects of a non-toxic strain (NPCS-1). Neonates (6-24 hours after birth) were exposed to concentrations of C. raciborskii varying from 102 to 106 cells·mL–1 of each strain for up to three hours. The cladocerans were then transferred to a medium without toxic filaments for 24 hours. Only the organisms exposed to the STX-producing strain showed signs of the immobilization of swimming movements, confirming the effects of the toxins. There was a linear correlation between the time required to induce stopping the swimming movement, with a shorter time to needed to induce immobilization at a higher the concentration; this correlation was inverse to the time required to recover the swimming movements (longer at higher concentrations, p < 0.1). D. laevis is a tropical and subtropical species with great potential for use in toxicity tests for the detection of STXs, despite being native to and found in a great array of freshwater bodies. This is the first assay testing STX-producing and non-producing C. raciborskii strains on D. laevis, species that are both found in Brazilian ecosystems.

Cylindrospermopsis raciborskii é uma espécie de cianobactéria, difundida mundialmente, conhecida como produtora de cianotoxinas. Algumas linhagens brasileiras são conhecidas como produtoras de saxitoxinas (STXs), as quais são classificadas como neurotoxinas e podem induzir a paralização dos movimentos natatórios em cladóceros. Daphnia laevis é um cladócero de ampla distribuição nas Américas e tem sido estudado como um organismo teste para uso em ensaios de toxicidade. Neste sentido, o presente trabalho avaliou os efeitos agudos de C. raciborskii, de uma cepa produtora de STXs (STX e neoSTX) - CYRF-01 e outra não produtora de cianotoxinas (NPCS-1) sobre a mobilidade de D. laevis. Para tanto, neonatas entre 6-24 horas de idade foram submetidas a concentrações de C. raciborskii variando de 102 a 106 céls.mL–1 de ambas as cepas, por um período de 3 horas, e transferidos posteriormente para um meio isento de filamentos tóxicos por 24horas. Apenas os organismos expostos à cepa produtora de STXs apresentaram paralisia dos movimentos natatórios, confirmando o efeito da cianotoxina. Houve uma correlação linear entre o tempo de paralização e as concentrações, isto é, nas concentrações mais altas, os organismos paralisaram num curto período de tempo, e conseqüentemente, levaram mais tempo para se recuperar (p < 0,1). D.laevis é uma espécie de região tropical e subtropical com potencial uso em bioensaios para detecção de STXs. Trata-se dos primeiros relatos acerca da resposta de D.laevis quando submetida às cepas de C. raciborskii produtora e não produtora de STXs, ambas isoladas de ecossistemas brasileiros.

Clinical and epidemiological study of 27 poisonings caused by ingesting puffer fish (Tetrodontidae) in the states of Santa Catarina and Bahia, Brazil / Estudo clinico-epidemiológico de 27 envenenamentos causados pela ingestão de baiacus (Tetrodontidae) nos estados de Santa Catarina e Bahia, Brasil

Puffer fish can be poisonous due to the presence of the potent neurotoxins such as Tetrodotoxin (TTX) and Saxitoxin (STX) found in its tissues. The authors report 27 human poisonings from ingestion of puffer fish in patients treated at Toxicology Centers in the states of Santa Catarina and Bahia, Brazil, between 1984 and January 2009. Poisonings were classified as moderate (52 percent) and severe (33 percent), two deaths were observed. Early diagnosis is very important to ensure respiratory support.

Os baiacus ou peixes-bola podem ser venenosos devido à presença em seus tecidos corporais de Tetrodotoxina e/ou Saxitoxina, ambas potentes neurotoxinas. Os autores relatam 27 envenenamentos por ingestão da carne de baiacus. Os pacientes foram atendidos nos Centros de Toxicologia de Santa Catarina e da Bahia de 1984 a 2009. Os acidentes foram classificados em moderados (52 por cento) e graves (33 por cento), havendo dois óbitos. O diagnóstico precoce é fundamental no sentido de garantir suporte ventilatório aos pacientes.

Screening the toxicity and toxin content of blooms of the cyanobacterium Trichodesmium erythraeum (Ehrenberg) in northeast Brasil

Blooms of the cyanobacterium Trichodesmium occur in massive colored patches over large areas of tropical and subtropical oceans. Recently, the interest in such events has increased given their role in major nitrogen and carbon dioxide oceanic fluxes. Trichodesmium occurs all along the Brazilian coast and patches frequently migrate towards the coast. In this paper we screen the toxicity and toxin content of Trichodesmium blooms off the coast of Bahia state. Four samples, collected from February to April 2007, were analyzed. Organisms were identified and assessed for toxicity by means of several methods. Analogues of microcystins, cylindrospermopsins and saxitoxins were analyzed using HPLC. Microcystins were also assayed through ELISA. Results showed dominance of T. erythraeum, which makes up as much as 99 percent of cell counts. Other organisms found in smaller quantities include the dinoflagellates Prorocentrum minimum and P. rhathymum. Extracts from all samples delayed or interrupted sea urchin larval development, but presented no acute toxicity during a mouse bioassay. Saxitoxin congeners and microcystins were present at low concentrations in all samples, occurrences that had not previously been reported in the literature. Despite our finding of saxitoxin analogues and microcystins in Trichodesmium blooms, these toxins do not represent a potential harm to human health by primary contact. We conclude, based on our results and those reported in the recent literature, which differ from results published in 1963, that although toxins are present, there is no evidence that T. erythraeum blooms represent a threat to humans.

Screening the toxicity and toxin content of blooms of the cyanobacterium Trichodesmium erythraeum (Ehrenberg) in northeast Brasil

Blooms of the cyanobacterium Trichodesmium occur in massive colored patches over large areas of tropical and subtropical oceans. Recently, the interest in such events has increased given their role in major nitrogen and carbon dioxide oceanic fluxes. Trichodesmium occurs all along the Brazilian coast and patches frequently migrate towards the coast. In this paper we screen the toxicity and toxin content of Trichodesmium blooms off the coast of Bahia state. Four samples, collected from February to April 2007, were analyzed. Organisms were identified and assessed for toxicity by means of several methods. Analogues of microcystins, cylindrospermopsins and saxitoxins were analyzed using HPLC. Microcystins were also assayed through ELISA. Results showed dominance of T. erythraeum, which makes up as much as 99% of cell counts. Other organisms found in smaller quantities include the dinoflagellates Prorocentrum minimum and P. rhathymum. Extracts from all samples delayed or interrupted sea urchin larval development, but presented no acute toxicity during a mouse bioassay. Saxitoxin congeners and microcystins were present at low concentrations in all samples, occurrences that had not previously been reported in the literature. Despite our finding of saxitoxin analogues and microcystins in Trichodesmium blooms, these toxins do not represent a potential harm to human health by primary contact. We conclude, based on our results and those reported in the recent literature, which differ from results published in 1963, that although toxins are present, there is no evidence that T. erythraeum blooms represent a threat to humans.

Occurrence of toxin-producing cyanobacteria blooms in a Brazilian semiarid reservoir

We report the occurrence of cyanobacterial blooms and the presence of cyanotoxins in water samples from the Armando Ribeiro Gonçalves reservoir (06° 08’ S and 37° 07’ W), located in the state of Rio Grande do Norte, in the semiarid region of northeastern Brazil. The cyanobacterial species were identified and quantified during the rainy and dry seasons in the year 2000. Cyanotoxins such as microcystins, saxitoxins and cylindrospermopsins were analyzed and quantified using HPLC and ELISA methods. The mixed toxic blooms of Cylindrospermopsis raciborskii, Microcystis spp (M. panniformis, M. protocystis, M. novacekii) and Aphanizomenon spp (Aphanizomenon gracile, A. cf. manguinii, A. cf. issastschenkoi) were persistent and represented 90-100% of the total phytoplankton species. Toxic cyanobacterial blooms from the Armando Ribeiro Gonçalves reservoir were analyzed and found to have three phases in relation to the annual cycle. During the rainy season, an intense toxic bloom of Cylindrospermopsis raciborskii was recorded along with saxitoxins (3.14 µg.L-1). During the transition period, between the rainy and dry seasons, different species of Microscytis occurred and microcystin as high as 8.8 µg.L-1 was recorded. In the dry season, co-dominance of Cylindrospermopsis raciborskii, Microcystis spp and Aphanizomenon spp occurred and the concentrations of saxitoxin remained very low. Our results indicate the presence of microcystins (8.8 µg.L-1) and saxitoxins (3.14 µg.L-1) into the crude water, with increasing concentrations from the second fortnight of April to late May 2000. The occurrence of toxic blooms in this reservoir points to a permanent risk of cyanotoxins in supply waters, indicating the need for the implementation of bloom control measures to improve the water quality. Exposure of the local population to cyanotoxins through their potential accumulation in fish muscle must also be considered.

Nós relatamos a ocorrência de florescimentos de cianobactérias e a presença de cianotoxinas em amostras de água do reservatório Armando Ribeiro Gonçalves (06° 08’ S; 37° 07’ W) situado no Estado do Rio Grande do Norte, na região semi-árida do Brasil. Cianobactérias foram identificadas e quantificadas nos períodos seco e chuvoso do ano 2000. Cianotoxinas tais como, microcistinas, saxitoxinas e cilindrospermopsinas foram quantificadas por HPLC e ELISA. Florescimentos tóxicos mistos de Cylindrospermopsis raciborskii, Microcystis spp (M. panniformis, M. protocystis, M. novacekii) e Aphanizomenon ssp (Aphanizomenon gracile, A. cf. manguinii, A. cf. issastschenkoi) foram persistentes e representaram 90-100% da comunidade fitoplanctônica ao longo do período estudado. No período de chuvas, florescimentos tóxicos de Cylindrospermopsis raciborskii coincidiram com maiores valores de saxitoxinas (3,14 µg.L-1). Entre o período de chuva e estiagem, ocorreram florescimentos tóxicos de Microcytis spp, excedendo o valor mínimo aceitável para consumo humano (8,8 µg.L-1). Na estiagem, baixas concentrações de saxitoxinas foram detectadas em florescimentos menos intensos com co-dominância de Cylindrospermopsis raciborskii, Microcystis spp e Aphanizomenon spp. Nossos resultados revelaram a presença de microcistinas (8,8 µg.L-1) e saxitoxinas (3,14 µg.L-1) na água bruta, a partir da segunda quinzena de abril até o final de maio de 2000. A ocorrência de blooms tóxicos de cianobactérias no reservatório em estudo aponta um risco permanente de cianotoxinas em águas de abastecimento e indica a necessidade da implementação de medidas de controle das florações, visando à melhoria da qualidade da água. A exposição das populações locais às cianotoxinas, pela sua potencial acumulação em musculatura de peixes, também deve ser considerada.

Pesquisa de toxina paralisante dos moluscos em pescado / Investigation of paralyzing toxin from molluscs in fish

A toxina paralisante dos moluscos foi pesquisada em amostras de ostras, mariscos e peixes, colhidas em diferentes praias do litoral paulista. Foram empregados dois procedimentos analíticos: o químico e o bioensaio. Em decorrência do aparecimento de manchas avermelhadas nas águas e mortalidade de peixes na região, no período de agosto a setembro de 1983, suspeitou-se do fenômeno de "maré vermelhra". A toxina não foi detectada em nenhuma das amostras, pelos dois métodos empregados, que permitem segurança dos resultados, considerando que os testes foram realizados com o padrão de saxi toxina (AU).