Articles de revues : « Cyanobacterial toxins Analysis »

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Codd, Geoffrey A., James S. Metcalf, Clive J. Ward, Kenneth A. Beattie, Steven G. Bell, Kunimitsu Kaya et Grace K. Poon. « Analysis of Cyanobacterial Toxins by Physicochemical and Biochemical Methods ». Journal of AOAC INTERNATIONAL 84, n^o 5 (1 septembre 2001) : 1626–35. http://dx.doi.org/10.1093/jaoac/84.5.1626.

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Abstract Cyanobacteria (blue-green algae) produce a wide range of low molecular weight metabolites that include potent neurotoxins, hepatotoxins, and cytotoxins. The accumulation of such toxins in freshwaters, and in brackish and marine waters presents hazards to human and animal health by a range of exposure routes. A review is presented of developments in the detection and analysis of cyanobacterial toxins, other than bioassays, including application of physicochemical, immunoassays, and enzyme-based methods. Analytical requirements are considered with reference to recently derived guideline levels for the protection of health and to the availability, or otherwise, of purified, quantitative cyanobacterial toxin standards.

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Mohamad, Rohaslinda, Mohd Rafatullah, Tengku Yusof, Yi Sim, Norli Ismail et Japareng Lalung. « Detection of Microcystin (Mcye) Gene in Recreational Lakes in Miri, Sarawak, Malaysia ». Current World Environment 11, n^o 3 (25 décembre 2016) : 690–99. http://dx.doi.org/10.12944/cwe.11.3.02.

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Toxic cyanobacteria blooms became a worldwide problems as many countries encounter the presence of the blooms in most of water bodies. As part to develop monitoring of cyanobacterial toxins in Malaysia, samples taken in twelve points in five different lakes in Miri, Sarawak. Polymerase chain reaction (PCR) amplification of cyanobacterial 16S rRNA were carried out to detect the presence of cyanobacteria in the water samples. Cyanobacterial 16S rRNA were detected in all the samples collected. While molecular analysis for detection of cyanobacterial toxin encoding gene were done using specific primers. PCR amplification of cyanobacterial toxin-encoding gene were carried using the combination of forward primer; mcyE-F2 and reverse primer; mcyE-R4 to amplify generic microcystin (mcyE) gene in the samples. Out of twelve samples collected, microcystin (mcyE) producing gene was detected in one of the samples tested. Presence of microcystin encoding gene indicates the risk of cyanobacterial toxins in Miri, Sarawak.

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Kormas, Konstantinos Ar, et Despoina S. Lymperopoulou. « Cyanobacterial Toxin Degrading Bacteria : Who Are They ? » BioMed Research International 2013 (2013) : 1–12. http://dx.doi.org/10.1155/2013/463894.

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Cyanobacteria are ubiquitous in nature and are both beneficial and detrimental to humans. Benefits include being food supplements and producing bioactive compounds, like antimicrobial and anticancer substances, while their detrimental effects are evident by toxin production, causing major ecological problems at the ecosystem level. To date, there are several ways to degrade or transform these toxins by chemical methods, while the biodegradation of these compounds is understudied. In this paper, we present a meta-analysis of the currently available 16S rRNA andmlrA(microcystinase) genes diversity of isolates known to degrade cyanobacterial toxins. The available data revealed that these bacteria belong primarily to the Proteobacteria, with several strains from the sphingomonads, and one from each of theMethylobacillusandPaucibactergenera. Other strains belonged to the generaArthrobacter, Bacillus, andLactobacillus. By combining the ecological knowledge on the distribution, abundance, and ecophysiology of the bacteria that cooccur with toxic cyanobacterial blooms and newly developed molecular approaches, it is possible not only to discover more strains with cyanobacterial toxin degradation abilities, but also to reveal the genes associated with the degradation of these toxins.

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Ikehara, Tsuyoshi, Kyoko Kuniyoshi, Haruyo Yamaguchi, Yuuhiko Tanabe, Tomoharu Sano, Masahiro Yoshimoto, Naomasa Oshiro, Shihoko Nakashima et Mina Yasumoto-Hirose. « First Report of Microcystis Strains Producing MC-FR and -WR Toxins in Japan ». Toxins 11, n^o 9 (9 septembre 2019) : 521. http://dx.doi.org/10.3390/toxins11090521.

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Microcystins (MCs) are a group of cyclic heptapeptide hepatotoxins produced by Microcystis and several other genera of cyanobacteria. Many structural variants have been characterized using various methods such as liquid chromatography–mass spectrometry (LC-MS) analysis, enzyme-linked immunosorbent assay (ELISA) and protein phosphatase 2A (PP2A) inhibition assay. The representative MC, MC-LR, and related cyanobacterial toxins strongly inhibit PP2A activity and can therefore be assayed by measuring the extent of PP2A inhibition. However, these methods require reference toxin standards for the quantification and identification of known MCs. To obtain various MC-producing cyanobacterial strains, we surveyed and collected MC-producing cyanobacteria from environmental sources of water in Okinawa, Japan. Using a dual assay (LC-MS analysis and PP2A inhibition assay), we identified and isolated Microcystis strains producing five MC variants (MC-LR, -RR, -LA, -FR and -WR). Approximately 4 mg of MC-WR and -FR toxins were purified from the laboratory culture of the Microcystis isolate NIES-4344. Pure MC-WR and -FR variants were prepared for future use as toxin standards in LC-MS analysis. Phylogenetic analysis based on ftsZ revealed that the NIES-4344 strain belongs to the identified groups in Microcystis aeruginosa. This is the first report of Microcystis strains producing mainly MC-WR and -FR toxins in Japan.

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Andeden, Enver Ersoy, Sahlan Ozturk et Belma Aslim. « Antiproliferative, neurotoxic, genotoxic and mutagenic effects of toxic cyanobacterial extracts ». Interdisciplinary Toxicology 11, n^o 4 (1 décembre 2018) : 267–74. http://dx.doi.org/10.2478/intox-2018-0026.

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Abstract Cyanobacteria are the rich resource of various secondary metabolites including toxins with broad pharmaceutical significance. The aim of this work was to evaluate the antiproliferative, neurotoxic, genotoxic and mutagenic effects of cyanobacterial extracts containing Microcystin-LR (MCLR) in vitro. ELISA analysis results showed that MCLR contents of five cyanobacterial extracts were 2.07 ng/mL, 1.43 ng/mL, 1.41 ng/mL, 1.27 ng/mL, and 1.12 ng/mL for Leptolyngbya sp. SB1, Phormidium sp. SB4, Oscillatoria earlei SB5, Phormidium sp. SB2, Uncultured cyanobacterium, respectively. Phormidium sp. SB4 and Phormidium sp. SB2 extracts had the lowest neurotoxicity (86% and 79% cell viability, respectively) and Oscillatoria earlei SB5 extracts had the highest neurotoxicity (47% cell viability) on PC12 cell at 1000 µg/ml extract concentration. Leptolyngbya sp. SB1 and Phormidium sp. SB2 showed the highest antiproliferative effect (92% and 77% cell death) on HT29 cell. On the other hand, all concentrations of five toxic cyanobacterial extracts induced DNA damage between 3.0% and 1.3% of tail intensity and did not cause any direct mutagenic effect at the 1000 µg/plate cyanobacterial extracts. These results suggest that cyanobacteria-derived MCLR is a promising candidate for development of effective agents against colon cancer.

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Everson, Sally, Larelle Fabbro, Susan Kinnear, Geoff Eaglesham et Paul Wright. « Distribution of the cyanobacterial toxins cylindrospermopsin and deoxycylindrospermopsin in a stratified lake in north-eastern New South Wales, Australia ». Marine and Freshwater Research 60, n^o 1 (2009) : 25. http://dx.doi.org/10.1071/mf08115.

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This paper describes the vertical water column distribution of the cyanobacterial toxins cylindrospermopsin and deoxycylindrospermopsin in a water body containing the cyanobacteria Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii. The study site was Cobaki Village Lake, a small stratified anthropogenic lake in north-eastern New South Wales, Australia. Water quality analysis indicated that stratification and oxygenation of the water column were significant in both the distribution of the cyanobacterial populations and their associated toxin concentrations. Toxin was distributed throughout the entire water column, but the highest concentrations were recorded in the hypolimnion. Maximum toxin concentrations were detected in February 2007 (38.2 μg L–1 cylindrospermopsin (CYN) and 42.2 μg L–1 deoxy-CYN). The relative distribution of CYN and deoxy-CYN paralleled the distribution of NH3H and NOX within the water column, with oxygenated chemical species dominating above 15 m and de-oxygenated chemical species dominating below 15 m. Cyanobacterial cell concentrations were highest in the oxic, warm and low conductivity waters of the epilimnion and cyanobacterial species succession was associated with nutrient and trace-metal depletion in this surface layer. These research findings are directly relevant to the management of water supplies affected by toxic blue-green algal blooms, particularly with respect to the considered placement of off-take devices to avoid layers of cyanobacterial cell and toxin concentrations.

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Khomutovska, Nataliia, Małgorzata Sandzewicz, Łukasz Łach, Małgorzata Suska-Malawska, Monika Chmielewska, Hanna Mazur-Marzec, Marta Cegłowska et al. « Limited Microcystin, Anatoxin and Cylindrospermopsin Production by Cyanobacteria from Microbial Mats in Cold Deserts ». Toxins 12, n^o 4 (11 avril 2020) : 244. http://dx.doi.org/10.3390/toxins12040244.

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Toxic metabolites are produced by many cyanobacterial species. There are limited data on toxigenic benthic, mat-forming cyanobacteria, and information on toxic cyanobacteria from Central Asia is even more scarce. In the present study, we examined cyanobacterial diversity and community structure, the presence of genes involved in toxin production and the occurrence of cyanotoxins in cyanobacterial mats from small water bodies in a cold high-mountain desert of Eastern Pamir. Diversity was explored using amplicon-based sequencing targeting the V3-V4 region of the 16S rRNA gene, toxin potential using PCR-based methods (mcy, nda, ana, sxt), and toxins by enzyme-linked immunosorbent assays (ELISAs) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Molecular identification of cyanobacteria showed a high similarity of abundant taxa to Nostoc PCC-73102, Nostoc PCC-7524, Nodularia PCC-935 and Leptolyngbya CYN68. The PCRs revealed the presence of mcyE and/or ndaF genes in 11 samples and mcyD in six. The partial sequences of the mcyE gene showed high sequence similarity to Nostoc, Planktothrix and uncultured cyanobacteria. LC-MS/MS analysis identified six microcystin congeners in two samples and unknown peptides in one. These results suggest that, in this extreme environment, cyanobacteria do not commonly produce microcystins, anatoxins and cylindrospermopsins, despite the high diversity and widespread occurrence of potentially toxic taxa.

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Moradinejad, Saber, Hana Trigui, Juan Francisco Guerra Maldonado, Jesse Shapiro, Yves Terrat, Arash Zamyadi, Sarah Dorner et Michèle Prévost. « Diversity Assessment of Toxic Cyanobacterial Blooms during Oxidation ». Toxins 12, n^o 11 (20 novembre 2020) : 728. http://dx.doi.org/10.3390/toxins12110728.

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Fresh-water sources of drinking water are experiencing toxic cyanobacterial blooms more frequently. Chemical oxidation is a common approach to treat cyanobacteria and their toxins. This study systematically investigates the bacterial/cyanobacterial community following chemical oxidation (Cl2, KMnO4, O3, H2O2) using high throughput sequencing. Raw water results from high throughput sequencing show that Proteobacteria, Actinobacteria, Cyanobacteria and Bacteroidetes were the most abundant phyla. Dolichospermum, Synechococcus, Microcystis and Nostoc were the most dominant genera. In terms of species, Dolichospermum sp.90 and Microcystis aeruginosa were the most abundant species at the beginning and end of the sampling, respectively. A comparison between the results of high throughput sequencing and taxonomic cell counts highlighted the robustness of high throughput sequencing to thoroughly reveal a wide diversity of bacterial and cyanobacterial communities. Principal component analysis of the oxidation samples results showed a progressive shift in the composition of bacterial/cyanobacterial communities following soft-chlorination with increasing common exposure units (CTs) (0–3.8 mg·min/L). Close cyanobacterial community composition (Dolichospermum dominant genus) was observed following low chlorine and mid-KMnO4 (287.7 mg·min/L) exposure. Our results showed that some toxin producing species may persist after oxidation whether they were dominant species or not. Relative persistence of Dolichospermum sp.90 was observed following soft-chlorination (0.2–0.6 mg/L) and permanganate (5 mg/L) oxidation with increasing oxidant exposure. Pre-oxidation using H2O2 (10 mg/L and one day contact time) caused a clear decrease in the relative abundance of all the taxa and some species including the toxin producing taxa. These observations suggest selectivity of H2O2 to provide an efficient barrier against toxin producing cyanobacteria entering a water treatment plant.

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Metcalf, J. S., et G. A. Codd. « Analysis of Cyanobacterial Toxins by Immunological Methods ». Chemical Research in Toxicology 16, n^o 2 (février 2003) : 103–12. http://dx.doi.org/10.1021/tx0200562.

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Kleinteich, J., F. Hildebrand, S. A. Wood, S. Ciŕs, R. Agha, A. Quesada, D. A. Pearce, P. Convey, F. C. K̈pper et D. R. Dietrich. « Diversity of toxin and non-toxin containing cyanobacterial mats of meltwater ponds on the Antarctic Peninsula : a pyrosequencing approach ». Antarctic Science 26, n^o 5 (14 mai 2014) : 521–32. http://dx.doi.org/10.1017/s0954102014000145.

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AbstractDespite their pivotal role as primary producers, there is little information as to the diversity and physiology of cyanobacteria in the meltwater ecosystems of polar regions. Thirty cyanobacterial mats from Adelaide Island, Antarctica were investigated using 16S rRNA gene pyrosequencing and automated ribosomal intergenic spacer analysis, and screened for cyanobacterial toxins using molecular and chemical approaches. A total of 274 operational taxonomic units (OTUs) were detected. The richness ranged between 8 and 33 cyanobacterial OTUs per sample, reflecting a high mat diversity. Leptolyngbya and Phormidium (c. 55% and 37% of the OTUs per mat) were dominant. Cyanobacterial community composition was similar between mats, particularly those obtained from closely adjacent locations. The cyanotoxin microcystin was detected in 26 of 27 mats (10–300 ng g-1 organic mass), while cylindrospermopsin, detected for the first time in Antarctica, was present in 21 of 30 mats (2–156 ng g-1 organic mass). The latter was confirmed via liquid chromatography-mass spectrometry and by the presence of the cyrAB and cyrJ genes. This study demonstrates the usefulness of pyrosequencing for characterizing diverse cyanobacterial communities, and confirms that cyanobacteria from extreme environments produce a similar range of cyanotoxins as their temperate counterparts.

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Cicerelli, Rejane Ennes, Maria de Lourdes B. Trindade Galo et Henrique Llacer Roig. « Multisource data for seasonal variability analysis of cyanobacteria in a tropical inland aquatic environment ». Marine and Freshwater Research 68, n^o 12 (2017) : 2344. http://dx.doi.org/10.1071/mf16259.

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Cyanobacterial blooms are related to eutrophic conditions that compromise the many uses of reservoirs. Thus, quick and effective methods for detecting the abundance of cyanobacteria in waterbodies are needed to complement conventional laboratory methods. In addition, inadequate control techniques that are applied at times of high cyanobacterial concentrations can cause the cells to lyse and release toxins into the water. In the present study we investigated the behaviour of cyanobacteria by determining phycocyanin and chlorophyll concentrations, using spectroradiometric and fluorometric techniques, in three field campaigns performed at the Nova Avanhandava Reservoir, Brazil. The sampling rate and favourable season for data collected had been determined previously by remote sensing analysis. Seasonal estimates of cyanobacteria were made because fluorometric sensors were able to record low concentrations, whereas the spectral analyses only detected phycocyanin at higher concentrations. Results of spectral analyses highlighted the subtle spectral characteristics indicating the presence of phycocyanin, even without a clear definition of the diagnostic features in the reflectance curve. Therefore, multiscale remote sensing complemented by fluorometric analysis and relevant environmental variables is an effective approach for monitoring cyanobacteria in Brazilian inland waters.

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Österholm, Julia, Rafael V. Popin, David P. Fewer et Kaarina Sivonen. « Phylogenomic Analysis of Secondary Metabolism in the Toxic Cyanobacterial Genera Anabaena, Dolichospermum and Aphanizomenon ». Toxins 12, n^o 4 (11 avril 2020) : 248. http://dx.doi.org/10.3390/toxins12040248.

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Cyanobacteria produce an array of toxins that pose serious health risks to humans and animals. The closely related diazotrophic genera, Anabaena, Dolichospermum and Aphanizomenon, frequently form poisonous blooms in lakes and brackish waters around the world. These genera form a complex now termed the Anabaena, Dolichospermum and Aphanizomenon (ADA) clade and produce a greater array of toxins than any other cyanobacteria group. However, taxonomic confusion masks the distribution of toxin biosynthetic pathways in cyanobacteria. Here we obtained 11 new draft genomes to improve the understanding of toxin production in these genera. Comparison of secondary metabolite pathways in all available 31 genomes for these three genera suggests that the ability to produce microcystin, anatoxin-a, and saxitoxin is associated with specific subgroups. Each toxin gene cluster was concentrated or even limited to a certain subgroup within the ADA clade. Our results indicate that members of the ADA clade encode a variety of secondary metabolites following the phylogenetic clustering of constituent species. The newly sequenced members of the ADA clade show that phylogenetic separation of planktonic Dolichospermum and benthic Anabaena is not complete. This underscores the importance of taxonomic revision of Anabaena, Dolichospermum and Aphanizomenon genera to reflect current phylogenomic understanding.

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Szczukocki, Dominik, Radosław Dałkowski, Barbara Krawczyk, Renata Juszczak, Luiza Kubisiak-Banaszkiewicz, Barbara Olejniczak et Grzegorz Andrijewski. « Cyanobacterial blooms in kaliski region water reservoirs and water quality parameters / Zakwity sinicowe w zbiornikach okolic Kalisza a wskaźniki jakości wody ». Archives of Environmental Protection 41, n^o 1 (1 mars 2015) : 15–23. http://dx.doi.org/10.1515/aep-2015-0002.

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Abstract Cyanobacterial blooms occur frequently in artificial lakes, especially in water reservoirs with small retention exposition to anthropopressure. The abundant occurrence of cyanobacteria is accompanied by danger of oxygen imbalance in the aquatic environment and the secretion of toxins that are possible threat to human health and life. Cyanobacterial cell growth depends on a number of physical (temperature, light exposure), chemical (pH, concentration of compounds containing nitrogen and phosphorus) and biological (the presence of other organisms) factors. This paper presents the results of the analysis of water from reservoirs located in southern Wielkopolska region (Pokrzywnica-Szałe, Gołuchów and Piaski-Szczygliczka). Some important physico-chemical parameters of water samples taken from investigated reservoirs as well as cyanotoxins concentration were determined. Furthermore, the cyanobacterial species were identified. There was also an attempt made to correlate the water parameters with the cyanobacteria development and cyanotoxins production. On the basis of the results obtained in the analyzed season, it can be concluded that water from Pokrzywnica and Gołuchów reservoirs was rich in nutrients, hence the intense cyanobacterial blooms and cyanotoxins in water were observed

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Grover, James P., J. Thad Scott, Daniel L. Roelke et Bryan W. Brooks. « Dynamics of nitrogen-fixing cyanobacteria with heterocysts : a stoichiometric model ». Marine and Freshwater Research 71, n^o 5 (2020) : 644. http://dx.doi.org/10.1071/mf18361.

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A simulation model for nitrogen-fixing cyanobacteria was formulated to predict population and nutrient dynamics in water quality studies. The model tracks population biomasses of nitrogen and phosphorus, which potentially limit population growth. Lack of intracellular nitrogen cues the differentiation of specialised heterocysts for nitrogen fixation. Ecoevolutionary analysis presented here predicts that natural selection optimises heterocyst differentiation in relation to external supplies of nitrogen and phosphorus. Modelling the production of N-rich toxins (e.g. anatoxins, saxitoxins) suggests that both total biomass and the biomass N:P ratio can predict concentrations of toxins. The results suggest hypotheses that major taxa of nitrogen-fixing, nuisance cyanobacteria are differentially adapted to varying nitrogen and phosphorus supplies, and that biomass stoichiometry is related to toxins production in this major group of harmful algae. This approach can be extended into models of community and ecosystem dynamics to explore implications of nitrogen fixation for cyanobacterial biomass and toxins production.

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KONDO, Fumio, et Ken-ichi HARADA. « Biological Mass Spectrometry. Mass Spectrometric Analysis of Cyanobacterial Toxins. » Journal of the Mass Spectrometry Society of Japan 44, n^o 3 (1996) : 355–76. http://dx.doi.org/10.5702/massspec.44.355.

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Lee, Jeong Ae, So Yeong Lee et Dong Jin Pyo. « Quantitative Analysis of Microcystins, Cyanobacterial Toxins in Soyang Lake ». Journal of the Korean Chemical Society 46, n^o 6 (20 décembre 2002) : 535–40. http://dx.doi.org/10.5012/jkcs.2002.46.6.535.

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Koreivienė, Judita, et Olga Belous. « Methods for Cyanotoxins detection ». Botanica Lithuanica 18, n^o 1 (1 octobre 2012) : 58–65. http://dx.doi.org/10.2478/v10279-012-0008-4.

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Abstract Koreivienė J., Belous O., 2012: Methods for cyanotoxins detection [Cianotoksinų nustatymo metodai]. - Bot. Lith., 18(1): 58-65. Global occurrence and concern about microcystin contamination, the potential consequences of exposure to cyanobacterial toxins in recreational and drinking waters promoted the development of numerous methods to detect the toxin and their producers as well as identification and quantification of toxins. In current study we overview numerous methods that have been developed for the cyanotoxin analysis. We discuss advantages and shortages of their applications to solve different questions.

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D'ors, A., M. C. Bartolomé et S. Sánchez-Fortún. « Importance of strain type to predict the toxicological risk associated with Microcystis aeruginosa blooms : comparison of Microtox® analysis and immunoassay ». Journal of Water and Health 10, n^o 2 (23 mars 2012) : 256–61. http://dx.doi.org/10.2166/wh.2012.081.

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The occurrence of toxic cyanobacterial blooms in aquatic environments, associated with human health problems and animal deaths, has increased the need for rapid, reliable and sensitive methods to determine the toxicity of microcystin produced by cyanobacteria. An in vitro Microtox® system and a commercially available microcystin ELISA were used to screen out the potential risk associated with selected Microcystis aeruginosa strains (Ma1D–Ma8D). Results showed the existence of three differentiated groups in the selected M. aeruginosa strains. Strains Ma7D and Ma6D were determined to be very toxic, strains Ma2D, Ma1D and Ma5D as moderately toxic and strains Ma8D, Ma4D and MA3D as non-toxic. These results agreed with the microcystin concentration values obtained by immunoassay. Although the data obtained by other authors clearly show that Microtox® is not sensitive to microcystins, our results suggested that this bioluminescence assay may prove useful in the preliminary screening of cyanobacterial blooms for microcystin-based toxicity. Additionally, the combination of immunodetection and toxicity-based Microtox® provides a useful addition to the methods already available for detection of cyanobacterial toxins.

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Hartnell, David M., Ian J. Chapman, Nick G. H. Taylor, Genoveva F. Esteban, Andrew D. Turner et Daniel J. Franklin. « Cyanobacterial Abundance and Microcystin Profiles in Two Southern British Lakes : The Importance of Abiotic and Biotic Interactions ». Toxins 12, n^o 8 (5 août 2020) : 503. http://dx.doi.org/10.3390/toxins12080503.

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Freshwater cyanobacteria blooms represent a risk to ecological and human health through induction of anoxia and release of potent toxins; both conditions require water management to mitigate risks. Many cyanobacteria taxa may produce microcystins, a group of toxic cyclic heptapeptides. Understanding the relationships between the abiotic drivers of microcystins and their occurrence would assist in the implementation of targeted, cost-effective solutions to maintain safe drinking and recreational waters. Cyanobacteria and microcystins were measured by flow cytometry and liquid chromatography coupled to tandem mass spectrometry in two interconnected reservoirs varying in age and management regimes, in southern Britain over a 12-month period. Microcystins were detected in both reservoirs, with significantly higher concentrations in the southern lake (maximum concentration >7 µg L−1). Elevated microcystin concentrations were not positively correlated with numbers of cyanobacterial cells, but multiple linear regression analysis suggested temperature and dissolved oxygen explained a significant amount of the variability in microcystin across both reservoirs. The presence of a managed fishery in one lake was associated with decreased microcystin levels, suggestive of top down control on cyanobacterial populations. This study supports the need to develop inclusive, multifactor holistic water management strategies to control cyanobacterial risks in freshwater bodies.

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Swanson-Mungerson, Michelle, Philip G. Williams, Joshua R. Gurr, Ryan Incrocci, Vijay Subramaniam, Kinga Radowska, Mary L. Hall et Alejandro M. S. Mayer. « Biochemical and Functional Analysis of Cyanobacterium Geitlerinema sp. LPS on Human Monocytes ». Toxicological Sciences 171, n^o 2 (4 juillet 2019) : 421–30. http://dx.doi.org/10.1093/toxsci/kfz153.

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Abstract Cyanobacterial blooms are an increasing source of environmental toxins that affect both human and animals. After ingestion of cyanobacteria, such as Geitlerinema sp., toxins and lipopolysaccharide (LPS) from this organism induce fever, gastrointestinal illness, and even death. However, little is known regarding the effects of cyanobacterial LPS on human monocytes after exposure to LPS upon ingestion. Based on our previous data using Geitlerinema sp. LPS (which was previously named Oscillatoria sp., a genus belonging to the same order as Geitlerinema), we hypothesized that Geitlerinema sp. LPS would activate human monocytes to proliferate, phagocytose particles, and produce cytokines that are critical for promoting proinflammatory responses in the gut. Our data demonstrate that Geitlerinema sp. LPS induced monocyte proliferation and TNF-α, IL-1, and IL-6 production at high concentrations. In contrast, Geitlerinema sp. LPS is equally capable of inducing monocyte-mediated phagocytosis of FITC-latex beads when compared with Escherichia coli LPS, which was used as a positive control for our experiments. In order to understand the mechanism responsible for the difference in efficacy between Geitlerinema sp. LPS and E. coli LPS, we performed biochemical analysis and identified that Geitlerinema sp. LPS was composed of significantly different sugars and fatty acid side chains in comparison to E. coli LPS. The lipid A portion of Geitlerinema sp. LPS contained longer fatty acid side chains, such as C15:0, C16:0, and C18:0, instead of C12:0 found in E. coli LPS which may explain the decreased efficacy and toxicity of Geitlerinema sp. LPS in comparison to E. coli LPS.

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Dell’Aversano, Carmela, Geoffrey K. Eaglesham et Michael A. Quilliam. « Analysis of cyanobacterial toxins by hydrophilic interaction liquid chromatography–mass spectrometry ». Journal of Chromatography A 1028, n^o 1 (février 2004) : 155–64. http://dx.doi.org/10.1016/j.chroma.2003.11.083.

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Aguete, E. C., A. Gago-Martínez, J. A. Rodríguez-Vázquez, S. O'Connell, C. Moroney et K. J. James. « Application of HPLC and HPCE to the analysis of cyanobacterial toxins ». Chromatographia 53, S1 (janvier 2001) : S254—S259. http://dx.doi.org/10.1007/bf02490338.

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Rantala-Ylinen, Anne, Suvi Känä, Hao Wang, Leo Rouhiainen, Matti Wahlsten, Ermanno Rizzi, Katri Berg, Muriel Gugger et Kaarina Sivonen. « Anatoxin-a Synthetase Gene Cluster of the Cyanobacterium Anabaena sp. Strain 37 and Molecular Methods To Detect Potential Producers ». Applied and Environmental Microbiology 77, n^o 20 (26 août 2011) : 7271–78. http://dx.doi.org/10.1128/aem.06022-11.

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ABSTRACTCyanobacterial mass occurrences are common in fresh and brackish waters. They pose a threat to water users due to toxins frequently produced by the cyanobacterial species present. Anatoxin-a and homoanatoxin-a are neurotoxins synthesized by various cyanobacteria, e.g.,Anabaena,Oscillatoria, andAphanizomenon. The biosynthesis of these toxins and the genes involved in anatoxin production were recently described forOscillatoriasp. strain PCC 6506 (A. Méjean et al., J. Am. Chem. Soc.131:7512-7513, 2009). In this study, we identified the anatoxin synthetase gene cluster (anaAtoanaGandorf1; 29 kb) inAnabaenasp. strain 37. The gene (81.6% to 89.2%) and amino acid (78.8% to 86.9%) sequences were highly similar to those ofOscillatoriasp. PCC 6506, while the organization of the genes differed. Molecular detection methods for potential anatoxin-a and homoanatoxin-a producers of the generaAnabaena,Aphanizomenon, andOscillatoriawere developed by designing primers to recognize theanaCgene.AnabaenaandOscillatoria anaCgenes were specifically identified in several cyanobacterial strains by PCR. Restriction fragment length polymorphism (RFLP) analysis of theanaCamplicons enabled simultaneous identification of three producer genera:Anabaena,Oscillatoria, andAphanizomenon. The molecular methods developed in this study revealed the presence of bothAnabaenaandOscillatoriaas potential anatoxin producers in Finnish fresh waters and the Baltic Sea; they could be applied for surveys of these neurotoxin producers in other aquatic environments.

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Metcalf, James S., Steven G. Bell et Geoffrey A. Codd. « Colorimetric Immuno-Protein Phosphatase Inhibition Assay for Specific Detection of Microcystins and Nodularins of Cyanobacteria ». Applied and Environmental Microbiology 67, n^o 2 (1 février 2001) : 904–9. http://dx.doi.org/10.1128/aem.67.2.904-909.2001.

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ABSTRACT A novel immunoassay was developed for specific detection of cyanobacterial cyclic peptide hepatotoxins which inhibit protein phosphatases. Immunoassay methods currently used for microcystin and nodularin detection and analysis do not provide information on the toxicity of microcystin and/or nodularin variants. Furthermore, protein phosphatase inhibition-based assays for these toxins are not specific and respond to other environmental protein phosphatase inhibitors, such as okadaic acid, calyculin A, and tautomycin. We addressed the problem of specificity in the analysis of protein phosphatase inhibitors by combining immunoassay-based detection of the toxins with a colorimetric protein phosphatase inhibition system in a single assay, designated the colorimetric immuno-protein phosphatase inhibition assay (CIPPIA). Polyclonal antibodies against microcystin-LR were used in conjunction with protein phosphatase inhibition, which enabled seven purified microcystin variants (microcystin-LR, -D-Asp3-RR, -LA, -LF, -LY, -LW, and -YR) and nodularin to be distinguished from okadaic acid, calyculin A, and tautomycin. A range of microcystin- and nodularin-containing laboratory strains and environmental samples of cyanobacteria were assayed by CIPPIA, and the results showed good correlation (R 2 = 0.94, P< 0.00001) with the results of high-performance liquid chromatography with diode array detection for toxin analysis. The CIPPIA procedure combines ease of use and detection of low concentrations with toxicity assessment and specificity for analysis of microcystins and nodularins.

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NIEDZWIADEK, BARBARA, PETER M. SCOTT et BEN P. Y. LAU. « Monitoring of Shrimp and Farmed Fish Sold in Canada for Cyanobacterial Toxins ». Journal of Food Protection 75, n^o 1 (1 janvier 2012) : 160–63. http://dx.doi.org/10.4315/0362-028x.jfp-11-324.

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Sixty-one samples of shrimp and 32 samples of farmed fish collected from retail markets across Canada were analyzed for cyanobacterial toxins, including microcystins, paralytic shellfish poisons (saxitoxins), cylindrospermopsin, and β-N-methylamino-l-alanine, using established methods of analysis. None of these toxins were detected in any of the samples. Some shrimp samples screened for paralytic shellfish poisons showed the presence of unknown peaks in the chromatogram after periodate oxidation.

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Vasas, Gábor, Attila Gáspár, Csilla Páger, Gyula Surányi, Csaba Máthé, Márta M. Hamvas et George Borbely. « Analysis of cyanobacterial toxins (anatoxin-a, cylindrospermopsin, microcystin-LR) by capillary electrophoresis ». ELECTROPHORESIS 25, n^o 1 (janvier 2004) : 108–15. http://dx.doi.org/10.1002/elps.200305641.

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Pomati, Francesco, Brendan P. Burns et Brett A. Neilan. « Identification of an Na+-Dependent Transporter Associated with Saxitoxin-Producing Strains of the Cyanobacterium Anabaena circinalis ». Applied and Environmental Microbiology 70, n^o 8 (août 2004) : 4711–19. http://dx.doi.org/10.1128/aem.70.8.4711-4719.2004.

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ABSTRACT Blooms of the freshwater cyanobacterium Anabaena circinalis are recognized as an important health risk worldwide due to the production of a range of toxins such as saxitoxin (STX) and its derivatives. In this study we used HIP1 octameric-palindrome repeated-sequence PCR to compare the genomic structure of phylogenetically similar Australian isolates of A. circinalis. STX-producing and nontoxic cyanobacterial strains showed different HIP1 (highly iterated octameric palindrome 1) DNA patterns, and characteristic interrepeat amplicons for each group were identified. Suppression subtractive hybridization (SSH) was performed using HIP1 PCR-generated libraries to further identify toxic-strain-specific genes. An STX-producing strain and a nontoxic strain of A. circinalis were chosen as testers in two distinct experiments. The two categories of SSH putative tester-specific sequences were characterized by different families of encoded proteins that may be representative of the differences in metabolism between STX-producing and nontoxic A. circinalis strains. DNA-microarray hybridization and genomic screening revealed a toxic-strain-specific HIP1 fragment coding for a putative Na+-dependent transporter. Analysis of this gene demonstrated analogy to the mrpF gene of Bacillus subtilis, whose encoded protein is involved in Na+-specific pH homeostasis. The application of this gene as a molecular probe in laboratory and environmental screening for STX-producing A. circinalis strains was demonstrated. The possible role of this putative Na+-dependent transporter in the toxic cyanobacterial phenotype is also discussed, in light of recent physiological studies of STX-producing cyanobacteria.

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Nagata, Satoshi, Tomoaki Tsutsumi, Akihiro Hasegawa, Fuyuko Yoshida, Yoshio Ueno et Mariyo F. Watanabe. « Enzyme Immunoassay for Direct Determination of Microcystins in Environmental Water ». Journal of AOAC INTERNATIONAL 80, n^o 2 (1 mars 1997) : 408–17. http://dx.doi.org/10.1093/jaoac/80.2.408.

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Abstract An enzyme-linked immunosorbent assay (ELISA) was developed for direct quantitation of microcys- tins (MCs), a group of freshwater cyanobacterial toxins. An anti-MC monoclonal antibody exhibiting broad cross-reactivity to major MC derivatives was used. The detection limit and linear range of the ELISA standard curve with microcystin-(leucine-ar-ginine) (MCLR), a variant of MCs, were 20 and 20–500 pg/mL, respectively. For analysis of MC released from cyanobacterial cells, water sample filtered through a glass fiber filter was applied directly to ELISA. For analysis of total MC (released MC plus intracellular MC), intracellular toxin was extracted by freeze-thawing twice before filtration. Mean recovery of MCLR added to tap water and toxin-free environmental water was 101%, with a coefficient of variation (CV) of 7.3% at toxin levels of 20–500 pg/mL. Mean recovery of MCLR added to toxin-free cyanobacterial extracts was 93%, with a CV of 12.5% at toxin levels of 50–500 pg/mL. At 20 pg/mL, an increasing matrix effect on assay variance was observed; therefore, both released MC and total MC were measured in the range 50–500 pg/ mL. Comparative studies with a liquid chromatographic (LC) method showed that the ELISA gives a reliable correlation with LC for analysis of MC in water extracts of natural blooms and cultured cyanobacterial cells (r = 0.98). The ELISA was applied to water samples collected from lakes and ponds in Japan. In 4 of 13 and 12 of 17 samples, 81–800 pg released MC/mL and 64–94 000 pg total MC/mL were detected, respectively. By LC separation followed by the ELISA analysis, the presence of MCLR, microcystin-arginine-arginine, and micro-cystin-tyrosine-arginine were confirmed in 4 ELISA-positive samples selected randomly. The newly developed ELISA is a reliable and powerful method for mass monitoring of MC levels in environmental water.

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Qu, Jiangqi, Liping Shen, Meng Zhao, Wentong Li, Chengxia Jia, Hua Zhu et Qingjing Zhang. « Determination of the Role of Microcystis aeruginosa in Toxin Generation Based on Phosphoproteomic Profiles ». Toxins 10, n^o 7 (23 juillet 2018) : 304. http://dx.doi.org/10.3390/toxins10070304.

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Microcystis aeruginosa is the most common species responsible for toxic cyanobacterial blooms and is considered a significant contributor to the production of cyanotoxins, particularly the potent liver toxins called microcystins. Numerous studies investigating Microcystis spp. blooms have revealed their deleterious effects in freshwater environments. However, the available knowledge regarding the global phosphoproteomics of M. aeruginosa and their regulatory roles in toxin generation is limited. In this study, we conducted comparative phosphoproteomic profiling of non-toxic and toxin-producing strains of M. aeruginosa. We identified 59 phosphorylation sites in 37 proteins in a non-toxic strain and 26 phosphorylation sites in 18 proteins in a toxin-producing strain. The analysis of protein phosphorylation abundances and functions in redox homeostasis, energy metabolism, light absorption and photosynthesis showed marked differences between the non-toxic and toxin-producing strains of M. aeruginosa, indicating that these processes are strongly related to toxin generation. Moreover, the protein-protein interaction results indicated that BJ0JVG8 can directly interact with the PemK-like toxin protein B0JQN8. Thus, the phosphorylation of B0JQN8 appears to be associated with the regulatory roles of toxins in physiological activity.

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Prepas, E. E., B. G. Kotak, L. M. Campbell, J. C. Evans, S. E. Hrudey et C. FB Holmes. « Accumulation and elimination of cyanobacterial hepatotoxins by the freshwater clam Anodonta grandis simpsoniana ». Canadian Journal of Fisheries and Aquatic Sciences 54, n^o 1 (1 janvier 1997) : 41–46. http://dx.doi.org/10.1139/f96-261.

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Freshwater clams (Anodonta grandis simpsoniana) exposed to 51-55 µg · L-1 of dissolved microcystin-LR (MC-LR) in the laboratory for 3 days did not accumulate MC-LR equivalents (MC-LReq). However, clams placed in three eutrophic lakes with phytoplankton containing MC-LR (concentrations from below detection to 8.3 µg · L-1 cellular toxin) for 12-28 days accumulated the toxin (24 ± 7 to 527 ± 330 ng · g-1 MC-LReq; mean ± SE). The relative MC-LReq concentrations in clams reflected MC-LR concentrations in lake phytoplankton, but individual variation was high. In individual clams exposed for 24 days, the average MC-LReq concentration was usually greater in the visceral mass than in gills and muscle, but average toxin concentrations in the three tissues were similar (587, 310, and 364 ng · g dry weight-1). In clams removed from the lake and placed in toxin-free water, MC-LReq concentrations in tissues declined rapidly for 6 days (by 69-88%) but remained relatively stable for the remaining 15 days. Analysis of clam tissues appears to be a more sensitive MC-LR indicator than analysis of phytoplankton. Accumulation of potent cyanobacterial toxins by this clam warrants further study as many are consumed by muskrats (Ondatra zibethicus), which in turn are consumed by terrestrial predators.

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Howard, Karen L., et Gregory L. Boyer. « Quantitative Analysis of Cyanobacterial Toxins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry ». Analytical Chemistry 79, n^o 15 (août 2007) : 5980–86. http://dx.doi.org/10.1021/ac0705723.

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Neilan, Brett A., Elke Dittmann, Leo Rouhiainen, R. Amanda Bass, Verena Schaub, Kaarina Sivonen et Thomas Börner. « Nonribosomal Peptide Synthesis and Toxigenicity of Cyanobacteria ». Journal of Bacteriology 181, n^o 13 (1 juillet 1999) : 4089–97. http://dx.doi.org/10.1128/jb.181.13.4089-4097.1999.

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ABSTRACT Nonribosomal peptide synthesis is achieved in prokaryotes and lower eukaryotes by the thiotemplate function of large, modular enzyme complexes known collectively as peptide synthetases. These and other multifunctional enzyme complexes, such as polyketide synthases, are of interest due to their use in unnatural-product or combinatorial biosynthesis (R. McDaniel, S. Ebert-Khosla, D. A. Hopwood, and C. Khosla, Science 262:1546–1557, 1993; T. Stachelhaus, A. Schneider, and M. A. Marahiel, Science 269:69–72, 1995). Most nonribosomal peptides from microorganisms are classified as secondary metabolites; that is, they rarely have a role in primary metabolism, growth, or reproduction but have evolved to somehow benefit the producing organisms. Cyanobacteria produce a myriad array of secondary metabolites, including alkaloids, polyketides, and nonribosomal peptides, some of which are potent toxins. This paper addresses the molecular genetic basis of nonribosomal peptide synthesis in diverse species of cyanobacteria. Amplification of peptide synthetase genes was achieved by use of degenerate primers directed to conserved functional motifs of these modular enzyme complexes. Specific detection of the gene cluster encoding the biosynthetic pathway of the cyanobacterial toxin microcystin was shown for both cultured and uncultured samples. Blot hybridizations, DNA amplifications, sequencing, and evolutionary analysis revealed a broad distribution of peptide synthetase gene orthologues in cyanobacteria. The results demonstrate a molecular approach to assessing preexpression microbial functional diversity in uncultured cyanobacteria. The nonribosomal peptide biosynthetic pathways detected may lead to the discovery and engineering of novel antibiotics, immunosuppressants, or antiviral agents.

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Sevilla, E., H. Smienk, P. Razquin, L. Mata et M. L. Peleato. « Optimization of intracellular microcystin-LR extraction for its analysis by protein phosphatase inhibition assay ». Water Science and Technology 60, n^o 7 (1 octobre 2009) : 1903–9. http://dx.doi.org/10.2166/wst.2009.527.

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Microcystins are toxins produced by some strains of cyanobacteria. Several methods have been developed to allow the quantification of microcystins, which are mainly endotoxins. Among those methods, the protein phosphatase inhibition assay is a good candidate as a screening method because of its sensitivity, simplicity and specificity. In this work a method for intracellular microcystin extraction in field water samples and lab cyanobacterial cultures prior to their analysis by protein phosphatase inhibition assay has been optimized. Microcystin-LR and Microcystis aeruginosa PCC 7806 were used as reference microcystin and strain, respectively, in order to optimize the protocol. The protocol consists on filtering the sample through a nylon filter of 0.8 μm, filter extraction with methanol 80% 0.1% trifluoroacetic acid (TFA) 0.1% tween 20, extract centrifugation and supernatant dilution (1/20). The establishment of an extraction protocol was carried out determining the extraction volume, time of extraction and number of extractions. The advantages of the method developed in this work are basically its simplicity and avoiding the use of specific and expensive equipment.

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Passos, Larissa Souza, Éryka Costa Almeida, Claudio Martin Pereira de Pereira, Alessandro Alberto Casazza, Attilio Converti et Ernani Pinto. « Chemical Characterization of Microcystis aeruginosa for Feed and Energy Uses ». Energies 14, n^o 11 (23 mai 2021) : 3013. http://dx.doi.org/10.3390/en14113013.

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Cyanobacterial blooms and strains absorb carbon dioxide, drawing attention to its use as feed for animals and renewable energy sources. However, cyanobacteria can produce toxins and have a low heating value. Herein, we studied a cyanobacterial strain harvested during a bloom event and analyzed it to use as animal feed and a source of energy supply. The thermal properties and the contents of total nitrogen, protein, carbohydrate, fatty acids, lipid, and the presence of cyanotoxins were investigated in the Microcystis aeruginosa LTPNA 01 strain and in a bloom material. Microcystins (hepatotoxins) were not detected in this strain nor in the bloom material by liquid chromatography coupled to mass spectrometry. Thermogravimetric analysis showed that degradation reactions (devolatilization) initiated at around 180 °C, dropping from approximately 90% to 20% of the samples’ mass. Our work showed that despite presenting a low heating value, both biomass and non-toxic M. aeruginosa LTPNA 01 could be used as energy sources either by burning or producing biofuels. Both can be considered a protein and carbohydrate source similar to some microalgae species as well as biomass fuel. It could also be used as additive for animal feed; however, its safety and potential adverse health effects should be further investigated.

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Díez-Quijada, Leticia, Remedios Guzmán-Guillén, Ana Prieto Ortega, María Llana-Ruíz-Cabello, Alexandre Campos, Vítor Vasconcelos, Ángeles Jos et Ana Cameán. « New Method for Simultaneous Determination of Microcystins and Cylindrospermopsin in Vegetable Matrices by SPE-UPLC-MS/MS ». Toxins 10, n^o 10 (8 octobre 2018) : 406. http://dx.doi.org/10.3390/toxins10100406.

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Cyanotoxins are a large group of noxious metabolites with different chemical structure and mechanisms of action, with a worldwide distribution, producing effects in animals, humans, and crop plants. When cyanotoxin-contaminated waters are used for the irrigation of edible vegetables, humans can be in contact with these toxins through the food chain. In this work, a method for the simultaneous detection of Microcystin-LR (MC-LR), Microcystin-RR (MC-RR), Microcystin-YR (MC-YR), and Cylindrospermopsin (CYN) in lettuce has been optimized and validated, using a dual solid phase extraction (SPE) system for toxin extraction and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for analysis. Results showed linear ranges (5–50 ng g−1 f.w.), low values for limit of detection (LOD) (0.06–0.42 ng g−1 f.w.), and limit of quantification (LOQ) (0.16–0.91 ng g−1 f.w.), acceptable recoveries (41–93%), and %RSDIP values for the four toxins. The method proved to be robust for the three variables tested. Finally, it was successfully applied to detect these cyanotoxins in edible vegetables exposed to cyanobacterial extracts under laboratory conditions, and it could be useful for monitoring these toxins in edible vegetables for better exposure estimation in terms of risk assessment.

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Hu, Jiaming, Jiaqi Liu, Yi Zhu, Zoraida Diaz-Perez, Michael Sheridan, Haley Royer, Raymond Leibensperger et al. « Exposure to Aerosolized Algal Toxins in South Florida Increases Short- and Long-Term Health Risk in Drosophila Model of Aging ». Toxins 12, n^o 12 (11 décembre 2020) : 787. http://dx.doi.org/10.3390/toxins12120787.

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Harmful algal blooms (HABs) are a rising health and environmental concern in the United States, particularly in South Florida. Skin contact and the ingestion of contaminated water or fish and other seafood have been proven to have severe toxicity to humans in some cases. However, the impact of aerosolized HAB toxins is poorly understood. In particular, knowledge regarding either the immediate or long-term effects of exposure to aerosolized cyanotoxins produced by freshwater blue-green algae does not exist. The aim of this study was to probe the toxicity of aerosolized cyanobacterial blooms using Drosophila melanogaster as an animal model. The exposure of aerosolized HABs at an early age leads to the most severe long-term impact on health and longevity among all age groups. Young groups and old males showed a strong acute response to HAB exposure. In addition, brain morphological analysis using fluorescence imaging reveals significant indications of brain degeneration in females exposed to aerosolized HABs in early or late stages. These results indicate that one-time exposure to aerosolized HAB particles causes a significant health risk, both immediately and in the long-term. Interestingly, age at the time of exposure plays an important role in the specific nature of the impact of aerosol HABs. As BMAA and microcystin have been found to be the significant toxins in cyanobacteria, the concentration of both toxins in the water and aerosols was examined. BMAA and microcystin are consistently detected in HAB waters, although their concentrations do not always correlate with the severity of the health impact, suggesting the potential contribution from additional toxins present in the aerosolized HAB. This study demonstrates, for the first time, the health risk of exposure to aerosolized HAB, and further highlights the critical need and importance of understanding the toxicity of aerosolized cyanobacteria HAB particles and determining the immediate and long-term health impacts of HAB exposure.

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Mbukwa, Elbert A., Titus A. M. Msagati et Bhekie B. Mamba. « Supported liquid membrane-liquid chromatography–mass spectrometry analysis of cyanobacterial toxins in fresh water systems ». Physics and Chemistry of the Earth, Parts A/B/C 50-52 (2012) : 84–91. http://dx.doi.org/10.1016/j.pce.2012.09.005.

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Krüger, Thomas, Claudia Wiegand, Li Kun, Bernd Luckas et Stephan Pflugmacher. « More and more toxins around–analysis of cyanobacterial strains isolated from Lake Chao (Anhui Province, China) ». Toxicon 56, n^o 8 (décembre 2010) : 1520–24. http://dx.doi.org/10.1016/j.toxicon.2010.09.004.

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Howard, Karen L., et Gregory L. Boyer. « Adduct simplification in the analysis of cyanobacterial toxins by matrix-assisted laser desorption/ionization mass spectrometry ». Rapid Communications in Mass Spectrometry 21, n^o 5 (2007) : 699–706. http://dx.doi.org/10.1002/rcm.2887.

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Somdee, Theerasak, et Anchana Somdee. « Comparison of different anion-exchange chromatography resins for the purification of cyanobacterial microcystins ». Water Supply 16, n^o 1 (18 juillet 2015) : 1–8. http://dx.doi.org/10.2166/ws.2015.108.

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For the first time, different types of diethylaminoethyl (DEAE) anion-exchange resins, widely used in previous studies, were investigated to determine the most effective resin for the purification of microcystins (MCs). MCs were extracted from freeze-dried Microcystis aeruginosa cells that had been harvested from the Bueng Nong Khot reservoir, Khon Kaen, Thailand. The toxins were precipitated with ammonium sulfate and then fractionated using five different anion-exchange chromatography resins, followed by chromatography with a C18 cartridge. The toxins were further identified via liquid chromatography–electrospray ionization–mass spectrometry (LC-ESI-MS) analysis, and the yields and purity were determined by high-performance liquid chromatography (HPLC) with ultraviolet detection. DEAE Sephadex A-25 exhibited the best overall performance for MC purification regarding both yield and purity, followed by DEAE cellulose, DEAE Sephacel, DEAE Sepharose Fast Flow and Toyopearl DEAE. Four MC variants, MC-RR, MC-FR, [Dha7]MC-LR and MC-WR, were obtained, and [Dha7]MC-LR was the major variant, with a total yield of 53.08 mg and a purity of 95% using the Sephadex resin. This study indicates that protein precipitation and single-column chromatography using DEAE Sephadex A-25 constitute an effective method for the purification of a wide range of MC variants.

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Ballot, Andreas, Thida Swe, Marit Mjelde, Leonardo Cerasino, Vladyslava Hostyeva et Christopher O. Miles. « Cylindrospermopsin- and Deoxycylindrospermopsin-Producing Raphidiopsis raciborskii and Microcystin-Producing Microcystis spp. in Meiktila Lake, Myanmar ». Toxins 12, n^o 4 (7 avril 2020) : 232. http://dx.doi.org/10.3390/toxins12040232.

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Meiktila Lake is a shallow reservoir located close to Meiktila city in central Myanmar. Its water is used for irrigation, domestic purposes and drinking water. No detailed study of the presence of cyanobacteria and their potential toxin production has been conducted so far. To ascertain the cyanobacterial composition and presence of cyanobacterial toxins in Meiktila Lake, water samples were collected in March and November 2017 and investigated for physico-chemical and biological parameters. Phytoplankton composition and biomass determination revealed that most of the samples were dominated by the cyanobacterium Raphidiopsis raciborskii. In a polyphasic approach, seven isolated cyanobacterial strains were classified morphologically and phylogenetically as R. raciborskii, and Microcystis spp. and tested for microcystins (MCs), cylindrospermopsins (CYNs), saxitoxins and anatoxins by enzyme-linked immunosorbent assay (ELISA) and liquid chromatography–mass spectrometry (LC–MS). ELISA and LC–MS analyses confirmed CYNs in three of the five Raphidiopsis strains between 1.8 and 9.8 μg mg−1 fresh weight. Both Microcystis strains produced MCs, one strain 52 congeners and the other strain 20 congeners, including 22 previously unreported variants. Due to the presence of CYN- and MC-producing cyanobacteria, harmful effects on humans, domestic and wild animals cannot be excluded in Meiktila Lake.

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Otten, Timothy G., Jennifer L. Graham, Theodore D. Harris et Theo W. Dreher. « Elucidation of Taste- and Odor-Producing Bacteria and Toxigenic Cyanobacteria in a Midwestern Drinking Water Supply Reservoir by Shotgun Metagenomic Analysis ». Applied and Environmental Microbiology 82, n^o 17 (24 juin 2016) : 5410–20. http://dx.doi.org/10.1128/aem.01334-16.

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ABSTRACTWhile commonplace in clinical settings, DNA-based assays for identification or enumeration of drinking water pathogens and other biological contaminants remain widely unadopted by the monitoring community. In this study, shotgun metagenomics was used to identify taste-and-odor producers and toxin-producing cyanobacteria over a 2-year period in a drinking water reservoir. The sequencing data implicated several cyanobacteria, includingAnabaenaspp.,Microcystisspp., and an unresolved member of the orderOscillatorialesas the likely principal producers of geosmin, microcystin, and 2-methylisoborneol (MIB), respectively. To further demonstrate this, quantitative PCR (qPCR) assays targeting geosmin-producingAnabaenaand microcystin-producingMicrocystiswere utilized, and these data were fitted using generalized linear models and compared with routine monitoring data, including microscopic cell counts, sonde-based physicochemical analyses, and assays of all inorganic and organic nitrogen and phosphorus forms and fractions. The qPCR assays explained the greatest variation in observed geosmin (adjustedR2= 0.71) and microcystin (adjustedR2= 0.84) concentrations over the study period, highlighting their potential for routine monitoring applications. The origin of the monoterpene cyclase required for MIB biosynthesis was putatively linked to a periphytic cyanobacterial mat attached to the concrete drinking water inflow structure. We conclude that shotgun metagenomics can be used to identify microbial agents involved in water quality deterioration and to guide PCR assay selection or design for routine monitoring purposes. Finally, we offer estimates of microbial diversity and metagenomic coverage of our data sets for reference to others wishing to apply shotgun metagenomics to other lacustrine systems.IMPORTANCECyanobacterial toxins and microbial taste-and-odor compounds are a growing concern for drinking water utilities reliant upon surface water resources. Specific identification of the microorganism(s) responsible for water quality degradation is often complicated by the presence of co-occurring taxa capable of producing these undesirable metabolites. Here we present a framework for how shotgun metagenomics can be used to definitively identify problematic microorganisms and how these data can guide the development of rapid genetic assays for routine monitoring purposes.

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Park, Hae-Kyung, Mi-Ae Kwon, Hae-Jin Lee, Jonghee Oh, Su-Heon Lee et In-Soo Kim. « Molecular Verification of Bloom-forming Aphanizomenon flos-aquae and Their Secondary Metabolites in the Nakdong River ». International Journal of Environmental Research and Public Health 15, n^o 8 (13 août 2018) : 1739. http://dx.doi.org/10.3390/ijerph15081739.

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Aphanizomenon spp. have formed harmful cyanobacterial blooms in the Nakdong River during spring, autumn, and now in winter, and the expansion of blooming period and area, associated with the global warming is predicted. The genus Aphanizomenon has been described to produce harmful secondary metabolites such as off-flavors and cyanotoxins. Therefore, the production of harmful secondary metabolites from the Aphanizomenon blooms in the Nakdong River needs to be monitored to minimize the risk to both water quality and public health. Here, we sampled the cyanobacterial blooms in the Nakdong River and isolated ten Aphanizomenon strains, morphologically classified as Aphanizomenon flos-aquae Ralfs ex Bornet et Flahault 1888. Phylogenetic analysis using 16S rRNA and internal transcribed spacer (ITS) region nucleotide sequences confirmed this classification. We further verified the harmful secondary metabolites-producing potential of A. flos-aquae isolates and water samples containing cyanobacterial blooms using PCR with specific primer sets for genes involved in biosynthesis of off-flavor metabolites (geosmin) and toxins (microcystins, saxitoxins and cylindrospermopsins). It was confirmed that these metabolite biosynthesis genes were not identified in all isolates and water samples containing only Aphanizomenon spp. Thus, it is likely that there is a low potential for the production of off-flavor metabolites and cyanotoxins in Aphanizomenon blooms in the Nakdong River.

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Kim Tiam, Sandra, Muriel Gugger, Justine Demay, Séverine Le Manach, Charlotte Duval, Cécile Bernard et Benjamin Marie. « Insights into the Diversity of Secondary Metabolites of Planktothrix Using a Biphasic Approach Combining Global Genomics and Metabolomics ». Toxins 11, n^o 9 (27 août 2019) : 498. http://dx.doi.org/10.3390/toxins11090498.

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Cyanobacteria are an ancient lineage of slow-growing photosynthetic bacteria and a prolific source of natural products with diverse chemical structures and potent biological activities and toxicities. The chemical identification of these compounds remains a major bottleneck. Strategies that can prioritize the most prolific strains and novel compounds are of great interest. Here, we combine chemical analysis and genomics to investigate the chemodiversity of secondary metabolites based on their pattern of distribution within some cyanobacteria. Planktothrix being a cyanobacterial genus known to form blooms worldwide and to produce a broad spectrum of toxins and other bioactive compounds, we applied this combined approach on four closely related strains of Planktothrix. The chemical diversity of the metabolites produced by the four strains was evaluated using an untargeted metabolomics strategy with high-resolution LC–MS. Metabolite profiles were correlated with the potential of metabolite production identified by genomics for the different strains. Although, the Planktothrix strains present a global similarity in terms of a biosynthetic cluster gene for microcystin, aeruginosin, and prenylagaramide for example, we found remarkable strain-specific chemodiversity. Only few of the chemical features were common to the four studied strains. Additionally, the MS/MS data were analyzed using Global Natural Products Social Molecular Networking (GNPS) to identify molecular families of the same biosynthetic origin. In conclusion, we depict an efficient, integrative strategy for elucidating the chemical diversity of a given genus and link the data obtained from analytical chemistry to biosynthetic genes of cyanobacteria.

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Wang, Xun, Peifang Wang, Chao Wang, Jin Qian, Tao Feng et Yangyang Yang. « Relationship between Photosynthetic Capacity and Microcystin Production in Toxic Microcystis Aeruginosa under Different Iron Regimes ». International Journal of Environmental Research and Public Health 15, n^o 9 (7 septembre 2018) : 1954. http://dx.doi.org/10.3390/ijerph15091954.

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Blooms of harmful cyanobacteria have been observed in various water bodies across the world and some of them can produce intracellular toxins, such as microcystins (MCs), which negatively impact aquatic organisms and human health. Iron participates significantly in cyanobacterial photosynthesis and is proposed to be linked to MC production. Here, the cyanobacteria Microcystis aeruginosa was cultivated under different iron regimes to investigate the relationship between photosynthetic capacity and MC production. The results showed that iron addition increased cell density, cellular protein concentration and the Chl-a (chlorophyll-a) content. Similarly, it can also up–regulate photosynthetic capacity and promote MC–leucine–arginine (MC–LR) production, but not in a dose–dependent manner. Moreover, a significant positive correlation between photosynthetic capacity and MC production was observed, and electron transport parameters were the most important parameters contributing to the variation of intracellular MC–LR concentration revealed by Generalized Additive Model analysis. As the electron transport chain was affected by iron variation, adenosine triphosphate production was inhibited, leading to the alteration of MC synthetase gene expression. Therefore, it is demonstrated that MC production greatly relies on redox status and energy metabolism of photosynthesis in M. aeruginosa. In consequence, more attention should be paid to the involvement of photosynthesis in the regulation of MC production by iron variation in the future.

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Wunsche, L., T. Vicari, S. L. M. Calado, J. Wojciechowski, V. F. Magalhães, H. C. S. Assis, D. M. Leme et M. M. Cestari. « Genotoxicity detected during cyanobacteria bloom in a water supply reservoir ». ECOTOXICOLOGY AND ENVIRONMENTAL CONTAMINATION 15 (10 novembre 2020) : 51–60. http://dx.doi.org/10.5132/eec.2020.01.07.

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The aquatic ecosystems are susceptible to cyanobacterial blooms due to the eutrophication of water bodies caused by human activities. In this study, phytoplankton and cyanotoxins analysis, as well as cellular and genetic biomarkers of toxicity (Allium cepa test - higher plant test system), were evaluated in water samples of Alagados Reservoir during a cyanobacterial bloom in South Brazil. The water samples were collected during the wet season at two sites in the Reservoir. Paralytic shellfish toxins (PSTs) were detected in both samples (sites 1 and 2); however, the levels of PSTs were higher in site 1. Gonyautoxin 2 was the major cyanotoxin found in the Reservoir. Both samples were able to induce cytotoxic effects (reduced Mitotic Index) and damage the genetic material (i.e., increased frequencies of chromosome aberration and micronuclei) of meristematic cells of A. cepa. The cellular and genetic damages were higher in the sample site 1, wherein high levels of PSTs were verified. Thus, our findings suggested that cyanotoxins-contaminated waters may damage the genetic material of living organisms, and therefore this group of contaminants should be assessed for their potential genotoxicity.

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Monchamp, Marie-Eve, Jean-Claude Walser, Francesco Pomati et Piet Spaak. « Sedimentary DNA Reveals Cyanobacterial Community Diversity over 200 Years in Two Perialpine Lakes ». Applied and Environmental Microbiology 82, n^o 21 (26 août 2016) : 6472–82. http://dx.doi.org/10.1128/aem.02174-16.

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ABSTRACTWe reconstructed cyanobacterial community structure and phylogeny using DNA that was isolated from layers of stratified sediments spanning 200 years of lake history in the perialpine lakes Greifensee and Lake Zurich (Switzerland). Community analysis based on amplification and sequencing of a 400-nucleotide (nt)-long 16S rRNA fragment specific toCyanobacteriarevealed operational taxonomic units (OTUs) capturing the whole phylum, including representatives of a newly characterized clade termedMelainabacteria, which shares common ancestry withCyanobacteriaand has not been previously described in lakes. The reconstruction of cyanobacterial richness and phylogenetic structure was validated using a data set consisting of 40 years of pelagic microscopic counts from each lake. We identified the OTUs assigned to common taxa known to be present in Greifensee and Lake Zurich and found a strong and significant relationship (adjustedR2= 0.89;P< 0.001) between pelagic species richness in water and OTU richness in the sediments. The water-sediment richness relationship varied between cyanobacterial orders, indicating that the richness ofChroococcalesandSynechococcalesmay be underestimated by microscopy. PCR detection of the microcystin synthetase genemcyAconfirmed the presence of potentially toxic cyanobacterial taxa over recent years in Greifensee and throughout the last century in Lake Zurich. The approach presented in this study demonstrates that it is possible to reconstruct past pelagic cyanobacterial communities in lakes where the integrity of the sedimentary archive is well preserved and to explore changes in phylogenetic and functional diversity over decade-to-century timescales.IMPORTANCECyanobacterial blooms can produce toxins that affect water quality, especially under eutrophic conditions, which are a consequence of human-induced climate warming and increased nutrient availability. Lakes worldwide have suffered from regular cyanobacterial blooms over the last century. The lack of long-term data limits our understanding of how these blooms form. We successfully reconstructed the past diversity of whole cyanobacterial communities over two hundred years by sequencing genes preserved in the sediments of two perialpine lakes in Switzerland. We identified changes in diversity over time and validated our results using existing data collected in the same two lakes over the past 40 years. This work shows the potential of our approach for addressing important ecological questions about the effects of a changing environment on lake ecology.

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Abbas, Feras, Cristina Porojan, Maxine A. D. Mowe, Mary Lehane, Simon M. Mitrovic, Richard P. Lim, Darren C. J. Yeo et Ambrose Furey. « Sample extraction and liquid chromatography–tandem mass spectrometry (LC-MS/MS) method development and validation for the quantitative detection of cyanobacterial hepatotoxins and neurotoxins in Singapore's reservoirs ». Marine and Freshwater Research 71, n^o 5 (2020) : 673. http://dx.doi.org/10.1071/mf19157.

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Cyanobacterial blue–green algal toxins are produced by harmful algal blooms (HABs). Most species of phytoplankton are not harmful, but excessive amounts of certain HAB taxa can cause harm to human and animal health, aquatic ecosystems and local economies. To investigate the prevalence of cylindrospermopsin (CYN) and anatoxin-a (ANA) in Singapore’s reservoirs, a hazard analysis was initiated to profile the CYN and ANA levels present. Water samples from 17 reservoirs were monitored monthly over a 12-month period (November 2012–October 2013). Analyses were conducted by liquid chromatography–tandem mass spectrometry (LC-MS/MS) using a triple-stage quadrupole mass spectrometer with a turbo-assisted ion spray source. CYN was more prevalent than ANA. Intracellular CYN concentrations exceeded 0.4μgL–1 in 6 of 17 man-made reservoirs surveyed, and slightly exceeded the provisional CYN drinking water guidelines of 1μgL–1 (National Health and Medical Research Council and National Resource Management Ministerial Council 2011) on one occasion (1.1μgL–1, July 2013) in one reservoir. The dominant cyanobacteria genera during that period were Cylindrospermopsis, Planktolyngbya, Pseudanabaena and Microcystis. For ANA, all 17 reservoirs had concentrations below 0.1μgL–1. Based on random forest analysis, the most important environmental factors affecting CYN concentrations were total nitrogen (most important), nitrate, total phosphorus and Cylindrospermopsis counts (least important). The findings of this study indicate that reducing total nitrogen concentrations may be useful in minimising CYN concentrations in tropical reservoirs.

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Rivasseau, Corinne, Sophie Martins et Marie-Claire Hennion. « Determination of some physicochemical parameters of microcystins (cyanobacterial toxins) and trace level analysis in environmental samples using liquid chromatography ». Journal of Chromatography A 799, n^o 1-2 (mars 1998) : 155–69. http://dx.doi.org/10.1016/s0021-9673(97)01095-9.

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Filatova, Daria, Oscar Núñez et Marinella Farré. « Ultra-Trace Analysis of Cyanotoxins by Liquid Chromatography Coupled to High-Resolution Mass Spectrometry ». Toxins 12, n^o 4 (11 avril 2020) : 247. http://dx.doi.org/10.3390/toxins12040247.

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The increasing frequency of episodes of harmful algal blooms of cyanobacterial origin is a risk to ecosystems and human health. The main human hazard may arise from drinking water supply and recreational water use. For this reason, efficient multiclass analytical methods are needed to assess the level of cyanotoxins in water reservoirs and tackle these problems. This work describes the development of a fast, sensitive, and robust analytical method for multiclass cyanotoxins determination based on dual solid-phase extraction (SPE) procedure using a polymeric cartridge, Oasis HLB (Waters Corporation, Milford, MA, USA), and a graphitized non-porous carbon cartridge, SupelcleanTM ENVI-CarbTM (Sigma-Aldrich, St. Louis, MO, USA), followed by ultra-high-performance liquid chromatography high-resolution mass spectrometry (SPE-UHPLC-HRMS). This method enabled the analysis of cylindrospermopsin, anatoxin-a, nodularin, and seven microcystins (MC-LR, MC-RR, MC-YR, MC-LA, MC-LY, MC-LW, MC-LF). The method limits of detection (MLOD) of the validated approach were between 4 and 150 pg/L. The analytical method was applied to assess the presence of the selected toxins in 21 samples collected in three natural water reservoirs in the Ter River in Catalonia (NE of Spain) used to produce drinking water for Barcelona city (Spain).

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