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1.
Toxicon ; 45(7): 901-9, 2005 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-15904685

RESUMO

Toxic cyanobacteria in public water supply reservoirs represent a serious health risk as they can release potent cyanotoxins into the water. In the present study we analyzed surface water collected from the Utinga Reservoir, the main source of drinking water for the city of Belem-PA, in order to characterize the reservoir's cyanobacterial biota and to determine the toxicity of these organisms and the concentration of microcystins in raw and treated water. The cyanobacterial biota included potentially toxic genera such as Aphanizomenon, Microcystis, Nostoc, Oscillatoria, Planktothrix and Radiocystis. Mouse bioassays revealed a 43.6% frequency of hepatotoxic strains, including 30.8% Microcystis viridis strains and 12.8% Radiocystis fernandoi strains, with the lowest LD(100) (ip) of 45 and 75 mg kg(-1) body weight, respectively. Subacute hepatotoxicity was observed for Aphanizomenon cf. gracile and Coelomoron pusillum strains. HPLC analysis confirmed the production of microcystins at maximum concentrations of 4.22 microg mg(-1) dry weight for M. viridis and 2.47 microg mg(-1) for R. fernandoi. Microcystins at concentrations of up to 1.25 microg L(-1) detected in raw water by ELISA, together with a cyanobacterial density of 20,000 cells mL(-1), represents the first report of a bloom of cyanobacteria for an Amazonian water body.


Assuntos
Toxinas Bacterianas/análise , Cianobactérias/metabolismo , Peptídeos Cíclicos/análise , Microbiologia da Água , Poluentes da Água/análise , Animais , Toxinas Bacterianas/biossíntese , Brasil , Cianobactérias/classificação , Cianobactérias/isolamento & purificação , Monitoramento Ambiental , Camundongos , Microcistinas , Peptídeos Cíclicos/biossíntese , Testes de Toxicidade Aguda , Poluentes da Água/metabolismo , Abastecimento de Água
2.
Toxicon ; 42(7): 709-13, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14757200

RESUMO

During the monitoring of toxic cyanobacteria in the Utinga Reservoir, which is the main drinking water supply for the city of Belém, PA, Brazil, a Radiocystis fernandoi strain (SPC714) was isolated. This non-axenic strain was submitted to a toxicity bioassay with mice and microcystin production analyzed by HPLC-DAD. The species was identified based on cultured and natural preserved material. Morphometric, developmental and reproductive characteristics were analyzed. The strain was cultured in liquid ASM-1 medium, at 25+/-1 degrees C, at an incident irradiance of 20 micromol photon m(-2)s(-1) and constant aeration. At the end of the exponential growth phase, cells were lyophilized and submitted to toxicity tests. The strain showed high toxicity to mice, by intraperitoneal route, with an approximate LD100 of 60 mg kg(-1) of body weight, producing characteristic symptoms of hepatotoxicity. Analyses performed by HPLC-DAD confirmed the production of microcystins, in a concentration of 3.83 microg mg(-1) of lyophilized cells. This is the first reference related to the toxicity of the genus Radiocystis.


Assuntos
Toxinas Bacterianas/biossíntese , Cianobactérias/isolamento & purificação , Cianobactérias/metabolismo , Peptídeos Cíclicos/biossíntese , Microbiologia da Água , Abastecimento de Água , Toxinas Bacterianas/análise , Brasil , Cromatografia Líquida de Alta Pressão , Humanos , Microcistinas , Peptídeos Cíclicos/análise
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