Effect of nitrate, ammonium and phosphate on the growth and microcystin production of Korean Microcystis species

Aim: This study aimed to investigate the effects of nitrogen (NO3-N, NH3-N) and phosphorus (PO4-P) on the growth and microcystin production of two bloom-forming Microcystis species (toxic M. aeruginosa MAHC160824 and non-toxic M. viridis MVHC160824).Methodology: The two Microcystis species were isolated from the lower reaches of the Nakdong river, South Korea. In the culture experiments, the average nutrient concentrations (NH3-N, NO3-N and PO4-P) at which Microcystis appeared (> 15°C) was used as control medium. Different concentrations of NH3-N, NO3-N and PO4-P were then employed in nutrient testing (control, vs. 4 times and 16 times higher than the control). Microcystin levels were measured using a UPLC™ (LC MS/MS) system. Results: Both toxic and non-toxic Microcystis strains exhibited a maximum cell density at 30°C and a maximum growth rate at 25-30°C. In the nutrient addition assays, the maximum growth of two Microcystis species were found at nutrient concentrations 4 to 16 times higher than the control (NH3-N: 0.468 mg l-1, PO4-P: 0.100 mg l-1, NO3-N: 32.5 mg l-1). The highest microcystin production levels were found under optimal growth conditions. The microcystin levels of toxic M. aeruginosa MAHC160824 were below the detection limit despite a higher number of cells (> 300,000 cells ml-1) at the same nutrients concentrations as those found in raw water from the Nakdong river. Interpretation: Higher production of microcystin occurs when there is an increase in NH3-N and PO4-P within a restricted range in toxic species M. aeruginosa MAHC160824, else the production is low

Pollution of microcystins in waters in Shaoxing City / 预防医学

Objective To understand microcystins (MCs) pollution in important waters of Shaoxing, so as to provide evidence for risk assessment and supervision of water quality safety. Methods Water samples were collected from 15 points set in three Shaoxing waters during September 2016 to September 2017. Six kinds of MCs (MC-LR, MC-RR, MC-YR, MC-LA, MC-LY, MC-LF) in samples were detected by ultra performance liquid chromatography tandem mass spectrometry, and the results were compared according to different time and place. Results MCs were detected positive in 22 of the 135 samples , the total detection rate was 16.3％.The detection rates of Xiaoshao River, Puyang River and Cao′e River were 7.9％, 18.5％和26.7％ respectively; the detection rates in July, August and September were 13.3％, 40％ and 46.7％ respectively, and the other months were not detected. In 22 positive samples, the detection rates of 6 MCs from high to low as follows: MC-LR (100％), MC-RR (100％), MC-YR (22.7％), MC-LY (18.2％), MC-LF (13.6％) and MC-LA (0％) . Conclusion In the three important waters of Shaoxing, microcystins were polluted in summer and autumn, which were mainly MC-LR and MC-RR.

Occurrence and toxicity of Microcystis aeruginosa (Cyanobacteria) in the Paraná River, downstream of the Yacyretá dam (Argentina) / Presencia y toxicidad de Microcystis aeruginosa (Cianobacteria) en el río Paraná, aguas abajo de la represa Yacyretá (Argentina)

AbstractCyanobacteria constitute the main toxin producers in inland water ecosystems and have extensive global distribution. The presence of hepatotoxins in aquatic environments is hazardous to human and animal health; even though the presence and identification of hepatotoxic microcystins in rivers and reservoirs of the world have been confirmed by several studies in the last few years. Herein, we studied the abundance and toxicity of Microcystis aeruginosa in the Argentine section of the Paraná River at the beginning of the Middle Paraná (Corrientes Hydrometer), near Corrientes city (27º28´ S - 58º51´ W) and approximately 220 km downstream of the Yacyretá dam (High Paraná). The Paraná River basin, with a drainage area of 3.1 x 106 km2 and 3 965 km in length, is the second largest catchment of South America, after that of the Amazon. The Paraná River is the main source of drinking water supply for the Northeastern Argentine region. Phytoplankton samples were collected and environmental variables were measured in a monthly basis (exceptionally fortnightly), from March 2004 to June 2008. Fifty-eight samples were analyzed for phytoplankton density and biomass. Five samples were used for toxicity testing; the latter were obtained during the cyanobacteria blooms from 2005 to 2008. Phytoplankton counts were performed with an inverted microscope, and biomass was expressed as biovolume. Bioassays with mice and high-performance liquid chromatography (HPLC) analysis were performed to evaluate the presence of cyanotoxins. Phytoplankton mainly consisted of Cryptophyta, Chlorophyta and Bacillariophyta. Microcystis aeruginosa was identified during the warmer months each year (November to March). Density varied between 189 and 25 027 cells/mL (1-10 colonies/mL) and biomass from 0.34 to 44 mm3/L. Taking into account the number of cells, the highest abundance occurred in April 2004 (25 027 cells/mL), coinciding with the largest biovolume (44 mm3/L). All mice subjected to intraperitoneal injections with samples obtained during bloom episodes showed positive results for the presence of hepatotoxins. Three microcystins variants: LR, RR and [D-Leu1] Mcyst-LR were detected by analysis with semi-preparative high-performance liquid chromatography with diode array detector system (HPLC-PDA). This constitutes the first report of microcystins recorded during M. aeruginosa blooms in the Argentine stretch of the Paraná River at the beginning of the Middle Paraná (Corrientes Hydrometer), approximately 220 km downstream of the Yacyretá dam (High Paraná).

ResumenLas Cyanobacterias constituyen el principal productor de toxinas en ecosistemas acuáticos y tienen una amplia distribución mundial. La presencia e identificación de microcistinas hepatotóxicas en ríos y embalses de todo el mundo fue confirmada por diferentes estudios durante los últimos años. La presencia de hepatotoxinas en cuerpos de agua son riesgosas para la salud humana y animal. Se estudió la abundancia y toxicidad de Microcystis aeruginosa (Kütz.) Kütz. en el río Paraná (Argentina), cerca de la ciudad de Corrientes (27°28' S - 58°51' W), aproximadamente a 220 km aguas abajo de la represa Yacyretá. La cuenca del río Paraná, con un área de drenaje de 3.1 x 106 km2 y 3 965 km de longitud, es la segunda mayor cuenca de Sudamérica, después del Amazonas. El río Paraná es la principal fuente de abastecimiento de agua potable para el Nordeste de la República Argentina. Los muestreos se realizaron mensualmente (excepcionalmente fueron quincenales) con medición de variables ambientales, entre Marzo 2004 y Junio 2008. Se tomaron un total de 58 muestras para analizar la densidad y biomasa del fitoplancton; mientras que cinco muestras fueron utilizadas en ensayos de toxicidad, estas últimas fueron obtenidas durante floraciones de cianobacterias entre 2005 y 2008. Los recuentos de fitoplancton fueron realizados con un microscopio invertido y la biomasa fue expresada como biovolumen. Para determinar la presencia de cianotoxinas se utilizaron bioensayos con ratones y análisis con Cromatografia líquida de alta resolución (HPLC). El fitoplancton estuvo representado principalmente por Cryptophyta, Chlorophyta y Bacillariophyta. Cyanobacteria fue dominante durante los meses cálidos de cada año (Noviembre a Marzo), con alta densidad de Microcystis aeruginosa. La densidad de M. aeruginosa varió entre 189 y 25 027 cells/mL (1-10 colonies/mL) y la biomasa entre 0.34 y 44 mm3/L. Teniendo en cuenta el número de células, la mayor abundancia ocurrió en abril 2004 (25 027 cells/ mL), coincidiendo con el gran biovolumen (44 mm3/L). Todos los ratones inyectados intraperitonealmente presentaron síntomas correspondientes a hepatotoxicidad. Tres variantes de microcystinas: LR, RR y [D-Leu1] Mcyst-LR, fueron detectadas por análisis de cromatografía líquida de alta resolución con detector de diodos (HPLC-PDA). Este es el primer trabajo de microcistinas registradas durante las floraciones de M. aeruginosa en el tramo argentino del río Paraná en los inicios del Paraná Medio (Hidrómetro Corrientes), aproximadamente a 220 km aguas abajo de la represa de Yacyretá (Alto Paraná).

Antimycobacterial and cytotoxicity activity of microcystins

Background: The present work aimed to evaluate the antimycobacterial activity and cytotoxicity of Microcystis aeruginosa toxins, the MC-LR variant and purified extract of [D-Leu1] microcystin-LR. Methods: The antimicrobial activity of M. aeruginosa extract and microcystin was evaluated by resazurin microtiter assay against Mycobacterium tuberculosis, M. terrae, M. chelonae and M. kansasii. The cytotoxicity assay was performed by trypan blue exclusion against the HTC cell line. Results: Antimicrobial activity was observed in the hexanic extract of M. aeruginosa (RST 9501 strain) against M. tuberculosis, including sensitive and resistant strains with minimal inhibitory concentrations (MIC) between 1.93 μM and 0.06 μM. The high activity of M. aeruginosa hexanic extract could be attributed to the major presence of the toxins MC-LR and [D-Leu1] MC-LR that showed activity at MIC between 53 and 0.42 μM against tested mycobacterial strains. Even at the highest concentration tested, no toxicity of M. aeruginosa extracts was identified against HTC cells. Conclusions: These preliminary results suggest that [D-Leu1] MC-LR is a promising candidate for the development of a new antimycobacterial agent.

Cylindrospermopsis raciborskii (Cyanobacteria, Nostocales) productora de microcistinas en Corrientes, Argentina / Cylindrospermopsis raciborskii (Cyanobacteria, Nostocales) producing microcystins in Corrientes, Argentina

Cylindrospermopsis raciborskii (Woloszyn´ ska) Seenayya et Subba Raju 1972 es una especie capaz de generar diversas toxinas que impactan negativamente sobre la calidad del agua destinada al consumo humano así como a otros usos de la misma. Cepas del hemisferio norte producen la hepatotoxina cilindrospermopsina, mientras que las sudamericanas generan las toxinas neurotóxicas saxitoxinas. No se ha reportado hasta el momento la producción de microcistinas por parte de esta especie El objetivo del presente estudio fue analizar la presencia de microcistinas en el agua del Arroyo Yatay en Corrientes, Argentina, y de cilindrospermopsina, saxitoxinas y microcistinas en cepas de C. raciborskii aisladas del mismo, mediante el ensayo por Inmuno Absorción Ligado a Enzimas (ELISA). Los resultados dieron negativos para microcistinas en el agua cruda, así como de cilindrospermopsina y saxitoxinas en el cultivo algal. Sin embargo, en el agua del cultivo se detectaron concentraciones de 2,34-2,50 µg. L-1 de microcistina-LR, confirmándose posteriormente su presencia mediante su análisis por Cromatografía Líquida de Alta Resolución (HPLC). En estudios posteriores se deberán realizar análisis moleculares a los fines de establecer la caracterización genética de la cepa en estudio e investigar su relación filogenética con otras cepas provenientes de diversos ambientes a nivel mundial.

Cylindrospermopsis raciborskii (Woloszyn´ ska) Seenayya et SubbaRaju 1972 is a species capable of generating toxins that negatively impact on drinking water quality as well as other water uses. Northern strains can produce the hepatotoxin cylindrospermopsin, while southern strains can produce the neurotoxin saxitoxins. Microcystins production by this species has not been reported to date.The aim of this study was to analyze the presence of microcystins in raw water of Steam Yatay in Corrientes, Argentina, and cylindrospermopsin, saxitoxins and microcystins in strains of C. raciborskii isolated from that stream, by means of Enzyme-Linked Immuno Sorbent Assay (ELISA).Results were negative for microcystins in raw water, as well as for cylindrospermopsin and saxitoxins in algal culture. Microcystins were detected in algal culture by ELISA test, at concentrations of 2.34-2.50 µg. L-1 of microcystin-LR, and subsequent confirmation by means of High Performance Liquid Chromatography (HPLC). Molecular studies should be carried out in the future to establish the genetic characterization of the strain under study and investigate their phylogenetic relationship with other strains from diverse environments.

Phytotoxicity associated to microcystins: a review / Fitotocixidade associada às microcistinas: uma revisão

Microcystins (MC) are the most studied toxins of cyanobacteria since they are widely distributed and account for several cases of human and animal poisoning, being potent inhibitors of the serine/threonine protein phosphatases 1 (PP1) and 2A (PP2A). The phosphatases PP1 and PP2A are also present in plants, which may also suffer adverse effects due to the inhibition of these enzymes. In aquatic plants, biomass reduction is usually observed after absorption of cyanotoxins, which can bioaccumulate in its tissues. In terrestrial plants, the effects caused by microcystins vary from inhibition to stimulation as the individuals develop from seedling to adult, and include reduction of protein phosphatases 1 and 2A, oxidative stress, decreased photosynthetic activity and even cell apoptosis, as well as bioaccumulation in plant tissues. Thus, the irrigation of crop plants by water contaminated with microcystins is not only an economic problem but becomes a public health issue because of the possibility of food contamination, and this route of exposure requires careful monitoring by the responsible authorities.

Microcistinas (MC) são as toxinas de cianobactérias mais estudadas, uma vez que são amplamente distribuídas e responsáveis por vários casos de intoxicação humana e animal. São potentes inibidoras das proteínas fosfatases serina/treonina 1 (PP1) e 2A (PP2A). As fosfatases PP1 e PP2A também estão presentes em plantas, as quais podem sofrer efeitos adversos devido à inibição dessas enzimas. Em plantas aquáticas, a redução da biomassa é geralmente observada após absorção de cianotoxinas que podem bioacumular em seus tecidos. Em plantas terrestres, os efeitos causados pelas microcistinas variam de inibição ao estímulo, como no desenvolvimento de plântulas ao estádio adulto, e incluem a redução de proteínas fosfatases 1 e 2A, estresse oxidativo, diminuição da atividade fotossintética e até mesmo apoptose celular, bem como a bioacumulação em tecidos de plantas. Assim, a irrigação de plantas cultivadas com água contaminada com microcistina não é apenas um problema econômico, mas torna-se um problema de saúde pública, devido à possibilidade de contaminação dos alimento, sendo uma via de exposição que requer um monitoramento cuidadoso por parte das autoridades responsáveis.

Técnicas moleculares para la detección de cianobacterias en los embalses Riogrande II y La Fe, Colombia / Molecular techniques for cyanobacteria detection at Riogrande II and La Fe water reservoirs, Colombia

In lentic water bodies as reservoirs occur eutrophication processes, originated mainly from human activities (i.e. agriculture, animal exploitation). This influx of nutrients in aquatic ecosystems could promote blooms of potentially toxic cyanobacteria. The purpose of this work is to detect the presence of cyanobacteria strains in water samples, using molecular techniques to help in preventive management of reservoirs dedicated to water purification. We used two molecular techniques to detect genes implied with the synthesis of hepatotoxic microcystins from potentially toxic cyanobacteria strains, and to evaluate the molecular diversity of cyanobacteria in water samples from two high-mountain reservoirs used for purification of drinking water for the metropolitan area of Medellin, Colombia. Between 2010-2011 collections of 12 water samples were taken and DNA extraction together with PCR and DGGE analyses where carried out. We amplified 22 sequences between 250-300bp of the genes mcyA and mcyE, and these sequences were related with several strains and cyanobacteria genera accessions from NCBI-GenBank databases. Moreover, sequence amplifications of the 16S small ribosomal RNA subunit - 16S rRNA- between 400-800bp were also performed in order to use them for the DGGE technique. The amplification products of DGGE were set in polyacrilamide gel with posterior denaturing electrophoresis, and the scanned images of the gel bands were analysed with the software GelCompar II. For Riogrande II and La Fe reservoirs we found 35 and 30 different DGGE bands, respectively, as a measurement of molecular diversity in these artificial ecosystems. Here, we demonstrated the utility of two molecular techniques for the detection of genes associated with toxicity and molecular diversity of cyanobacteria in reservoirs destined for drinking water in urban centers. We recommend strongly following with periodically molecular biology studies in these ecosystems combined with limnological and ecological data, as new tools for management of plants of water purification and for the prevention of potentially public health concerns. Rev. Biol. Trop. 62 (1): 403-419. Epub 2014 March 01.

En embalses, la eutrofización es consecuencia de procesos naturales y de actividades humanas, lo cual puede facilitar la aparición de afloramientos de cianobacterias potencialmente tóxicas. En este trabajo, se utilizaron dos técnicas moleculares en la detección de genes presentes en cepas potencialmente tóxicas de cianobacterias y evaluaciones de diversidad molecular de cianobacterias en los embalses para potabilización de agua, Riogrande II y La Fe, Colombia. Entre 2010-2011, se tomaron 12 muestras de agua en ambos embalses y se realizaron extracciones de ADN para un análisis de marcadores moleculares mediante PCR y DGGE. Se amplificaron secuencias entre 250-300pb de los genes mcyA y mcyE, implicados en la toxicidad de cepas de cianobacterias. Asimismo, se amplificaron secuencias de la región 16S del ARN ribosomal (422pb), para la técnica DGGE. Se corrieron geles de poliacrilamida en gradientes de desnaturalización, se realizó agrupamiento genético (UPGMA), y se separaron por patrones de bandeo las muestras de cada embalse evaluado. Se demuestra la utilidad de las técnicas moleculares en estudios relacionados con la búsqueda de genes asociados con toxicidad y diversidad molecular de cianobacterias en muestras de agua provenientes de embalses de agua con fines de potabilización para centros urbanos.

Electrochemical Immunosensor for Determination of Microcystins Based on Carbon Nanotubes/Au Nanoparticles Composite Film / 分析化学

Carbon nanotubes/Au nanoparticles ( CNT/AuNP ) composite film was fabricated on glassy carbon electrode ( GCE) by first dropping CNTs on the electrode surface and then electrodeposition of AuNPs by multi-potential step. The antibody of microcystin-( leucine-arginine ) ( anti-MCLR ) was immobilized on the modified electrode surface through adsorption on AuNPs. Subsequently, bovine serum albumin ( BSA) was used to block the non-specific adsorption to obtain the immunosensor for MCLR assay. The immunosensor could effectively capture MCLR by the specific immunoreaction between the electrode surface-confined antibody and MCLR, followed by the attachment of the anti-MCLR HRP-labeled to form a sandwich-type system. The analysis of MCLR was performed based on the catalytic reaction of HRP toward the oxidation of hydroquinone ( QH2 ) by H2 O2 . Under the optimal experimental conditions, the peak current response increased linearly with the concentration of MCLR in the range of 0 . 50-12 μg/L with a detection limit of 0. 30 μg/L (S/N=3). The developed immunosensor was used to determine MCLR in real water samples, and the recoveries of standard addition experiments were in the range of 93 . 0%-108 . 5%, with the relative standard deviation of 3 . 8%-5 . 0%.

Biodegradacao da hepatotoxina(D-Leu1)-microcistina-LR por bacterias presentes em filtros biologicos de carvao / Biodegradation of hepatotoxin (D-Leu1)-microcystin-LR by bacteria in carbon biological filters

A persistência das microcistinas (MCs) em ambientes aquáticos e sua difícil remoção no tratamento convencional de água representam um desafio às companhias de saneamento. Contudo, as MCs são susceptíveis à degradação por bactérias presentes na água, sedimentos e efluentes de esgotos. Neste estudo, avaliou-se a biodegradação de MCs por microrganismos presentes em filtros de carvão com atividade biológica (CAB) e sua identificação filogenética pelo sequenciamento do gene 16S RNA. Foi utilizada uma água de estudo contendo MCs com diferentes composições, acrescida de efluente de filtros CAB. Os resultados demonstraram que as MCs foram biodegradadas por microrganismos presentes no biofilme. Este estudo infere sobre a capacidade de biodegradação de MCs por bactérias presentes em filtros CAB e o possível uso destes microorganismos como alternativa de remoção de MCs no tratamento de água potável.

The persistence of MCs in aquatic environments and their difficult removal in the conventional water treatment is a challenge to companies of sanitation. However, the MCs are susceptible to degradation by bacteria present in water, sediment and sewage effluents. In this study, we investigated the biodegradation of MCs by microorganism present in carbon filters with biological activity (BAC) and their phylogenetic identification by sequencing gene 16S RNA. A study of water containing MCs was used, with different compositions, plus a filters BAC effluent. The results showed that of MCs were biodegraded by microorganism present in the biofilm. This study provides the ability to complete biodegradation of MCs by bacteria present in BAC filters and the possible use of these microorganisms as alternative of the removal of MCs in the treatment of drinking water.

A toxic cyanobacterial bloom in an urban coastal lake, Rio Grande do Sul state, Southern Brazil / Uma floração de cianobacterias em um lago costeiro urbano, Rio Grande do Sul, Brasil

Reports of cyanobacterial blooms developing worldwide have considerably increased, and, in most cases, the predominant toxins are microcystins. The present study reports a cyanobacterial bloom in Lake Violão, Torres, Rio Grande do Sul State, in January 2005. Samples collected on January 13, 2005, were submitted to taxonomical, toxicological, and chemical studies. The taxonomical analysis showed many different species of cyanobacteria, and that Microcystis protocystis and Sphaerocavum cf. brasiliense were dominant. Besides these, Microcystis panniformis, Anabaena oumiana,Cylindrospermopsis raciborskii, and Anabaenopsis elenkinii f. circularis were also present. The toxicity of the bloom was confirmed through intraperitoneal tests in mice, and chemical analyses of bloom extracts showed that the major substance was anabaenopeptin F, followed by anabaenopeptin B, microcystin-LR, and microcystin-RR.

O número de relatos de ocorrências de florações de cianobactérias em todo o mundo vem aumentando consideravelmente e na maioria desses episódios, as toxinas dominantes são as microcistinas. O presente estudo relata a ocorrência de floração na Lagoa do Violão, município de Torres, RS, em janeiro de 2005. As amostras coletadas em 13/01/2005 foram submetidas a estudos taxonômicos, toxicológicos e químicos. O exame microscópico do fitoplancton mostrou a dominância das espécies Microcystis protocystis e Sphaerocavum cf. brasiliense; foram observadas, também, Microcystis panniformis, Anabaena oumiana,Cylindrospermopsis raciborskii e Anabaenopsis elenkinii f. circularis. A toxicidade da floração foi confirmada através de ensaio intraperitonial em camundongos e a análise química de extratos obtidos da biomassa liofilizada mostrou que a substância majoritária era a anabaenopeptina F, seguida por anabaenopeptina B, microcistina-LR e microcistina-RR.

Determination and Pollution Control of Microcystins / 环境与健康杂志

As a most common algal toxin in eutrophic freshwater body, microcystins can be produced by the bloom-forming Cyanophyta microcystis, it has become a potential hazardous substance in aquatic environments for its toxic, distribution and stability. With the increasing recognition of microcystins, China had added microcystin-LR into the related water quality standards. It is very important to detect and control the microcystins in the aquatic environment. This paper systematically introduced the current situation of researches about the determination and pollution control technique of microcystins in drinking water at home and abroad in resent years and then some issues worth of paying more attention to and doing further study in pollution control in future were presented.

Microcystins in drinking water and cancer mortality in a city along Taihu Lake / 中国癌症杂志

Purpose: To study the relationship of microcystins ( MC) in drinking water to cancer mortality. Methods: An ecological study was carried out in Wuxi, Jiangsu Province. Ten districts and counties with different types of drinking water were selected. Cancer mortality during 1992 to 2000 was collected, and the MC contents in different types of drinking water were tested for evaluating the level of MC exposure. The relationship between cancer mortality and MC in drinking water was analyzed. Results: MC in drinking water was positively correlated with the male overall cancer mortality and male stomach cancer mortality; and was negatively correlated with the male intestinal cancer mortality( P

Investigation of M icrocystin Pollution in Yanghe Reservoir in Qinhuangdao / 环境与健康杂志

Objective To know the pollution of microcystin(MC) in Yanghe reservoir during the period of water blooms in the summer of 2007 and to find the variation characteristics about the pollution.Methods The microcystin concentration was determined by ELISA Kit.A 49 consecutive days monitoring was conducted during Jul.-Aug.,2007.Results The concentration of MC in Yanghe reservoir ranged from 0.13 ?g/L to 0.93 ?g/L,and its average level was(0.26 ?0.13)?g/L.As well as,the concentration of MC in Yanghe reservoir descended fluctuant.Conclusion Water in Yanghe reservoir was polluted by MC.All monitoring results of MC concentration during seven weeks(49 days) did not exceed the limit value of microcystin toxin,1 ?g/L for MC-LR,the grade two water ruled in China Environmental Quality Standard for Surface Water.The basic data for changing regularity of MC studied in the present paper will be useful for the warning of alga pollution.

Detection Techniques of Microcystins in Aquatic Environment: a Review Based on Recent Researches / 环境与健康杂志

Microcystins(MCs) released from cyanobacteria(blue-green algae) contaminate the most wide fresh water. With the increasing of water contaminated by MCs, researchers have paid more attention to MCs. The detection is the basis of the control of microcystins in aquatic environment. It is absolutely necessary to select a fast, economical and sensitive method to determine MCs. This review introduced several kinds of detecting methods for MCs and the prospects of MCs detection was discussed also.

Removing Efficiency of Microcystin in Drinking Water:an Experimental Study / 环境与健康杂志

Objective To explore the efficient, cheaper and practical water treatment process in removing algae toxins. Methods The different water treatment methods were used and the optimal combination was selected. The removing efficiency for different processes was compared and validated by beaker test. The enzyme-linked immunosorbent assay (ELISA) was conducted in microcystin testing. Results Coagulating sedimentation could remove a small part of microcystin (removing efficiency was from 4.3% to 29.7% ). When oxidants were applied in pretreatment processes, such as ozone combined with coagulant, 83.3% to 91.9% microcystin could be removed. The cost-benefit analysis showed these processes only increased 0.03 to 0.14 yuan RMB cost per cubic meter of water, for example, by using ozone pretreatment and oxidation plus adsorption processes. Conclusion On the basis of general water treatment, ozone(O3), potassium permanganate(KMnO4), chlorine, dioxide(ClO2)and powdered activated carbon(PAC) are effective for removing microcystin in pretreatment processes and the processes are cheaper and practical.

Progress of Researches on Potential Chemoprotectants against Microcystins / 环境与健康杂志

Microcystins (MCs) is a potent cyclic heptapeptide hepatotoxin produced by the blue-green algae,Microcystis aeruginosa. The pollution caused by microcystins has become a global concern. Facing to MCs-induced health hazards and potential economic losses,it has an important practical significance to study the effective chemoprotectants against MCs. In this paper,both domestic and abroad researches on the chemoprotectants (silymarin,curcumin,green tea polyphenols,cyclosporin-A,rifampin,trace element supplementation) against MCs were reviewed.

Detection of Potential Microcystin-Producing Cyanobacteria in Waters With a mcyD Molecular Biomarker / 环境与健康杂志

Objective To develop a new method to screen the potential microcystin-producing cyanobacteria in natural waters. Methods Cyanobacteria were cultured and waters samples were analyzed by polymerase chain reaction with special primers for gene of the operon mcyD which encodes a microcystin synthetase combining conserved gene 16S rRNA of alga, subsequently, whose microcystins were detected by ELISA. Results There was a unique amplified product of approximately 870 bp in microcystin-producing blue-green alga and water samples, but no target band in non-toxic strains and samples. Conclusion It is feasible to use the molecular biological method used mcyD as the microcystin molecular biomarker to screen microcystin-producing cyanobacteria in natural water.

The Pollution and Control of Microcystins in Water / 环境与健康杂志

Pollution and control of microcystins released during the toxic bloom was reviewed in the present paper. As a risk factor in safety assessment, microcystins aroused broad attention. It was a topic of general interest that how to control microcystins reproduction and how to enhance the degradation of microcystins in the water treatment procedure. Based on the state of China, it was considered that a combined method of biological, physical and chemical treatment should be the best way to control microcystins pollution in drinking water.