Highly Toxic Microcystis aeruginosa Strain, Isolated from São Paulo—Brazil, Produce Hepatotoxins and Paralytic Shellfish Poison Neurotoxins (original) (raw)
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Toxicological Studies on Microcystin Produced by Microcystis aeruginosa : Assessment and Management
2019
MICROCYSTIS aeruginosa is a kind of cyanobacteria microorganism that synthesizes and produces peptides, which could be highly toxic. The most common toxin known as microcystin (MCs) or cyanotoxins, these toxins are heptapeptides produced by cyanobacterial blooms on water surfaces. They potentially lead to acute to chronic health-related problems via increasing reactive oxygen species (ROS) and irreversible inhibition of serine/threonine protein phosphatases. The toxicological studies of MCs on experimental animal and cell models have promise interests; however, few information is known about their impacts on humans due to acute or chronic exposure. This review article aimed to present some of the information about the cyanotoxins structure, occurrence, and distribution of the cyanobacterial toxins especially excreted from M. aeruginosa. Also, toxicological studies and investigations associated with M. aeruginosa producing microcystin, their assessments and control and health problem...
Hepatotoxin microcystin-LR extraction optimization
Journal of the Brazilian Chemical Society, 2009
Vários gêneros de cianobactérias produzem metabólitos secundários tóxicos, entre eles as hepatotoxinas microcistinas. A análise de microcistinas em águas para abastecimento humano é uma exigência do Ministério da Saúde (Portaria 518/2004), mas essa portaria ainda não estabelece o método de extração e análise a serem usados e a quantificação da toxina é comumente realizada por ELISA ("enzyme-linked immunosorbent assay") ou HPLC (cromatografia líquida de alta eficiência), cuja eficiência depende do método de extração utilizado. Neste trabalho foi desenvolvido um método simples, rápido e barato de extração para o isolamento e identificação de microcistinas. Para isso, selecionou-se a linhagem Microcystis aeruginosa NPLJ-4 descrita como produtora de microcistina-LR. Oito diferentes tratamentos foram testados para determinar a melhor extração da toxina. As amostras foram analisadas por LC-MS (cromatografia líquida acoplada a espectrometria de massas), ELISA e Q-TOF ("quadrupole time-of-flight"). Os resultados mostraram que a melhor extração foi a que usou sonicação das amostras diluídas em água. O método proposto permite o processamento rápido das amostras e estabelece um método de extração para análise e identificação de microcistina-LR e outras variantes.
The cyanotoxin-microcystins: current overview
Reviews in Environmental Science and Bio/Technology, 2014
The monocyclic heptapeptides microcystins (MCs), are a group of hepatotoxins, produced worldwide by some bloom-forming cyanobacterial species/strains both in marine and freshwater ecosystems. MCs are synthesized non-ribosomally by large multi-enzyme complexes consisting of different modules including polyketide synthases and non-ribosomal peptide synthetases, as well as several tailoring enzymes. More than 85 different variants of MCs have been reported to exist in nature. These are chemically stable, but undergo bio-degradation in natural water reservoirs. Direct or indirect intake of MCs through the food web is assumed to be a highly exposed route in risk assessment of cyanotoxins. MCs are the most commonly found cyanobacterial toxins that cause a major challenge for the production of safe drinking water and pose a serious threat to global public health as well as fundamental ecological processes due to their potential carcinogenicity. Here, we emphasize recent updates on different modes of action of their possible carcinogenicity. Besides the harmful effects on human and animals, MC producing cyanobacteria can also present a harmful effect on growth and development of agriculturally important plants. Overall, this review emphasizes the current understanding of MCs with their occurrence, geographical distribution, accumulation in the aquatic as well as terrestrial ecosystems, biosynthesis, climate-driven changes in their synthesis, stability and current aspects on its degradation, analysis, mode of action and their ecotoxicological effects.
Applied and Environmental Microbiology
A strain of the filamentous cyanobacterium Nostoc sp. isolated from a lake in Finland was found to produce at least nine hepatotoxic peptides with chemical and toxicological properties similar to those of the hepatotoxic heptaand pentapeptides produced by other cyanobacteria. Toxins were isolated and purified by highperformance liquid chromatography. Amounts available for five of the purified toxins (P6, P14, P15, P16, and P18) were adequate for high-performance liquid chromatography amino acid analysis and determination of molecular weight by fast-atom bombardment-mass spectrometry (FAB-MS). Quantities of three toxins (P14, P15, and P16) were adequate for further analysis by high-resolution FAB-MS, FAB-MS/MS, and 'H-nuclear magnetic resonance. Analysis showed that the toxins are new types of microcystin-LR homologs. Microcystin-LR contains equimolar amounts of D-alanine, L-leucine, D-erythro-4-methylaspartic acid, L-arginine, ADDA (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyl-4,6-decadienoic acid), D-glutamic acid, and N-methyldehy-