Importancia biológica de la microcistina en aguas de riego y alternativas en su detección y degradación / Biological importance of microcistin in irrigation and alternative waters in its detection and degradation

Introducción: Las cianobacterias son microrganismos fotosintéticos, con capacidad de sintetizar una gran diversidad de metabolitos secundarios de interés para la industria, pero también han llamado la atención en las últimas décadas las toxinas denominas cianotoxinas, metabolitos que causan distintas alternaciones fisiológicas hasta llegar ocasionar la muerte de diferentes especies. Metodología: La determinación del estado de arte para el tema de cianobacterias se basó en una búsqueda bibliográfica en la base de datos especializada como Elservier, Springer, Google académico y MDPI basadas en palabras clave en español e inglés "microcistinas", "degradación de MC" y "cuantificación y detección de MC". Resultados: En la presente revisión considera dos áreas de caracterización de la microcistinas (MCs) las propiedades fisicoquímicas y propiedades biológicas, para entender su comportamiento e importancia tóxica en los sembradíos agrícolas y en la salud humana. Además de comprender alternativas para su degradación, por métodos fisicoquímicos como fotocatálisis y la gradación biológica por bacterias. Finalmente se mencionará algunos métodos actuales y en desarrollo, para la detección y cuantificación de estas MCs en ambientes acuáticos. Conclusiones: Las MCs tienen el potencial contaminar fuentes de agua como ríos y lagunas, causando daños a la salud humana y a las plantas agrícolas, tienen la capacidad de tolerar distintos cambios drásticos en factores fisicoquímicos y biológicos. Entre las alternativas reportadas la degradación bacteriana promete ser la más confiable. Finalmente, entre los distintos métodos para la detección de MCs, entre los métodos más aplicados son los inmunoensayos, debido a su versatilidad y estabilidad del método.

Introduction: Cyanobacteria are photosynthetic microorganisms, with the capacity to synthesize a great diversity of secondary metabolites of interest to the industry, but toxins called cyanotoxins have also attracted attention in recent decades, metabolites that cause different physiological alterations until they cause the death of different species. Methodology: The determination of the state of the art for the subject of cyanobacteria was based on a bibliographic search in specialized databases such as Elservier, Springer, Google Scholar and MDPI based on keywords in Spanish and English "microcystins", "MC degradation " and "quantification and detection of MC". Results: In the present review, two areas of characterization of microcystins are considered: the physicochemical properties and biological properties of microcystins (MC), to understand their behavior and toxic importance in agricultural crops and in human health.In addition to understanding alternatives for their degradation, by physicochemical methods such as photocatalysis and biological grading by bacteria.Finally, some current and developing methods will be mentioned for the detection and quantification of these MCs in aquatic environments. Conclusions: MCs have the potential to contaminate water sources such as rivers and lagoon, causing damage to human health and agricultural plants, they have the ability to tolerate different drastic changes in physicochemical and biological factors. Among the reported alternatives, bacterial degradation promises to be the most reliable. Finally, among the different methods for the detection of MCs, among the most applied methods are immunoassays, due to their versatility and stability of the method.

Microcistina en plantas de tratamiento de agua para consume humano en un ambiente tropical: el Area Metropolitana de Costa Rica / Microcystin in plants that treat water for human consumption in a tropical environment: the Metropolitan Area of Costa Rica

We measured microcystin levels in water of the Metropolitan Area of Costa Rica by competitive inhibition ELISA and we quantified total coliforms, fecal coliforms, Escherichia coli (by a Most Probable Number method) and aerobic count. We wanted to identify any cyanotoxin correlation with these parameters, as a public health risk. We sampled in the rainy season of 2003 (April-October) and in the dry season of 2004 (February-March) (30 samples/season). We sampled pre-treated, semi-treated and treated water. Microcystin levels < 0.5 ppb were found in the rainy season (and > 0.5 ppb in the dry season). Dry season levels exceeded World Health Organization limits (1.0 ppb). Cyanotoxins occurred in the Tres Rios plant. We did not find a correlation between these microbiologic parameters of water quality and microcystin levels in water.

Se midió la presencia de microcistina en el Área Metropolitana de Costa Rica por la técnica de ELISA de inhibición competitiva y se cuantificó coliformes totales, coliformes termotolerantes, Escherichia coli (por medio de la técnica Numero Más Probable) y recuento total aerobio. Se realizaron dos etapas de muestreo, una durante la estación lluviosa del 2003 (abril-octubre) y otra durante la estación seca del 2004 (febrero-marzo), cada una con 30 muestras de agua. Se muestreó agua pretratada, semitratada y tratada. Se determinaron niveles de microcistina < 0.5 ppb durante la estación lluviosa del 2003, mientras que durante la estación seca, se detectaron concentraciones de microcistina > 0.5 ppb. Se informó la presencia de cianotoxinas en la Planta de Tratamiento de Tres Ríos. No se establece correlación entre los parámetros microbiológicos de calidad del agua y las concentraciones de microcistina en el agua. Los estudios deberían considerar la diversidad y toxicidad de cianobacterias en estas plantas, los efectos del tratamiento, y presencia de otros microorganismos y sustancias (dióxido de carbono, fósforo, Nitrógeno), sobre la presencia, estructura y efecto de estas toxinas.

Hepatotoxicidade da cianotoxina microcistina / Hepatotoxicity of the microcystin cyanotoxin

Constitui interesse emergente em saúde pública avaliar a possibilidade de intoxicação humana por biotoxinas de algas cianofíceas, principalmente as hepatotoxinas do grupo das microcistinas. A microcistina, um heptapeptídeo monocíclico, é produzida principalmente pela cianobactéria Microcistis aeruginosa. São caracterizadas por alguns aminoácidos variáveis, dois deles com uma estrutura não usual que possuem importante papel na hepatotoxidade da microcistina. Apesar do acometimento humano atribuído as microcistinas incluírem gastroenterite, reações alérgicas ou irritativas, neurotoxicidade, o principal alvo da toxina é o fígado. Nos hepatócitos as microcistinas são carreadas pelo sistema transportador do ácido biliar, inibindo a atividade da proteína fosfatase no citoplasma. A inibição leva a mudanças morfológicas na membrana plasmática pela hiperfosforilação de citoqueratinas, e à atividade de promoção tumoral pelas proteínas hiperfosforiladas. Os métodos de detecção e quantificação de microcistinas no ambiente incluem a cromatografia líquida, o bioensaio em camundongos e os testes imunoenzimáticos. O último vem ganhando destaque pela praticidade e alta sensibilidade.

At public health, there is increasingly interest on evaluating the possibility of human intoxication by biotoxins from blue-green algae, mainly the hepatotoxins from the microcystin group. Microcystin, a monocyclic heptapeptide, is mainly produced by a cyanobacteria called Microcistis aeruginosa. It is characterized by a few variable amino acids, from which two of them have an unusual structure and play an important role in the hepatotoxicity of the microcystin. Although human illnesses include gastroenteritis, allergic or irritative reactions, and neurotoxicity, the main target of this toxin is the liver. Inside the hepatocytes, microcystins are carried by the transportation system of the bile acid, inhibiting the activity of the protein phosphatase in the cytoplasm. This inhibition causes a morphologic change in the plasmatic membrane because of the hyperphosphorylation of cytokeratins, and also the tumoral promotion by the hyperphosphorylated proteins. The techniques used in the detection and quantification of the microcystins in the environment include liquid chromatography, bioanalysis of mice, and immunoenzymatic tests using mono and polyclonal antibodies against those toxins. The latter has been remarked because of its practicality and its high sensibility.