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Senger M.R.,Oswaldo Cruz Institute FIOCRUZ | Senger M.R.,Federal University of Rio Grande do Sul | Seibt K.J.,Pontifical Catholic University of Rio Grande do Sul | Seibt K.J.,National Institute of Science and Technology for Translational Medicine | And 7 more authors.
Cell Biology and Toxicology | Year: 2011

Aluminum is a metal that is known to impact fish species. The zebrafish has been used as an attractive model for toxicology and behavioral studies, being considered a model to study environmental exposures and human pathologies. In the present study, we have investigated the effect of aluminum exposure on brain acetylcholinesterase activity and behavioral parameters in zebrafish. In vivo exposure of zebrafish to 50 μg/L AlCl3 for 96 h at pH 5.8 significantly increased (36%) acetylthiocholine hydrolysis in zebrafish brain. There were no changes in acetylcholinesterase (AChE) activity when fish were exposed to the same concentration of AlCl3 at pH 6.8. In vitro concentrations of AlCl3 varying from 50 to 250 μM increased AChE activity (28% to 33%, respectively). Moreover, we observed that animals exposed to AlCl3 at pH 5.8 presented a significant decrease in locomotor activity, as evaluated by the number of line crossings (25%), distance traveled (14.1%), and maximum speed (24%) besides an increase in the absolute turn angle (12.7%). These results indicate that sublethal levels of aluminum might modify behavioral parameters and acetylcholinesterase activity in zebrafish brain. © Springer Science+Business Media B.V. 2011.

Lemes G.A.F.,Grande Rio University | Kist L.W.,Pontifical Catholic University of Rio Grande do Sul | Bogo M.R.,Pontifical Catholic University of Rio Grande do Sul | Bogo M.R.,National Institute of Science and Technology for Translational Medicine | Yunes J.S.,Grande Rio University
Journal of Venomous Animals and Toxins Including Tropical Diseases | Year: 2015

Background: Toxic cyanobacterial blooms are recurrent in Patos Lagoon, in southern Brazil. Among cyanotoxins, [D-Leu1] microcystin-LR is the predominant variant whose natural cycle involves water and sediment compartments. This study aimed to identify and isolate from sediment a bacterial strain capable of growing on [D-Leu1] microcystin-LR. Sediment and water samples were collected at two distinct aquatic spots: close to the Oceanographic Museum (P1), in Rio Grande City, and on São Lourenço Beach (P2), in São Lourenço do Sul City, southern Brazil.Methods: [D-Leu1] microcystin-LR was isolated and purified from batch cultures ofMicrocystis aeruginosastrain RST9501. Samples of water and sediment from Rio Grande and São Lourenço do Sul were collected. Bacteria from the samples were allowed to grow in flasks containing solely [D-Leu1] microcystin-LR. This strain named DMSX was isolated on agar MSM with 8 g L-1glucose and further purified on a cyanotoxin basis growth. Microcystin concentration was obtained by using the ELISA immunoassay for microcystins whereas bacterial count was performed by epifluorescence microscopy. The genusPseudomonaswas identified by DNA techniques.Results: Although several bacterial strains were isolated from the samples, only one, DMXS, was capable of growing on [D-Leu1] microcystin-LR. The phylogenetic analysis of the 16S rRNA gene from DMXS strain classified the organism asPseudomonas aeruginosa. DMXS strain incubated with [D-Leu1] microcystin-LR lowered the amount of toxin from 1 μg.L-1to < 0.05 μg.L-1. Besides, an increase in the bacterial count-from 71 × 105bacteria.mL-1to 117 × 105bacteria.mL-1-was observed along the incubation.Conclusions: The use of bacteria isolated from sediment for technological applications to remove toxic compounds is viable. Studies have shown that sediment plays an important role as a source of bacteria capable of degrading cyanobacterial toxins. This is the first Brazilian report on a bacterium-of the genusPseudomonas-that can degrade [D-Leu1] microcystin-LR, the most frequent microcystin variant in Brazilian freshwaters. © 2015 Lemes et al.; licensee BioMed Central.

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