{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T19:51:27Z","timestamp":1776109887106,"version":"3.50.1"},"reference-count":54,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2011,9,29]],"date-time":"2011-09-29T00:00:00Z","timestamp":1317254400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Marine Drugs"],"abstract":"<jats:p>Blooms of toxic cyanobacteria are becoming increasingly frequent, mainly due to water quality degradation. This work applied qPCR as a tool for early warning of microcystin(MC)-producer cyanobacteria and risk assessment of water supplies. Specific marker genes for cyanobacteria, Microcystis and MC-producing Microcystis, were quantified to determine the genotypic composition of the natural Microcystis population. Correlations between limnological parameters, pH, water temperature, dissolved oxygen and conductivity and MC concentrations as well as Microcystis abundance were assessed. A negative significant correlation was observed between toxic (with mcy genes) to non-toxic (without mcy genes) genotypes ratio and the overall Microcystis density. The highest proportions of toxic Microcystis genotypes were found 4\u20136 weeks before and 8\u201310 weeks after the peak of the bloom, with the lowest being observed at its peak. These results suggest positive selection of non-toxic genotypes under favorable environmental growth conditions. Significant positive correlations could be found between quantity of toxic genotypes and MC concentration, suggesting that the method applied can be useful to predict potential MC toxicity risk. No significant correlation was found between the limnological parameters measured and MC concentrations or toxic genotypes proportions indicating that other abiotic and biotic factors should be governing MC production and toxic genotypes dynamics. The qPCR method here applied is useful to rapidly estimate the potential toxicity of environmental samples and so, it may contribute to the more efficient management of water use in eutrophic systems.<\/jats:p>","DOI":"10.3390\/md9101715","type":"journal-article","created":{"date-parts":[[2011,9,29]],"date-time":"2011-09-29T11:34:46Z","timestamp":1317296086000},"page":"1715-1730","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Seasonal Dynamics of Microcystis spp. and Their Toxigenicity as Assessed by qPCR in a Temperate Reservoir"],"prefix":"10.3390","volume":"9","author":[{"given":"Ant\u00f3nio","family":"Martins","sequence":"first","affiliation":[{"name":"CIIMAR\/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, 289, Porto 4050-123, Portugal"}]},{"given":"Cristiana","family":"Moreira","sequence":"additional","affiliation":[{"name":"CIIMAR\/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, 289, Porto 4050-123, Portugal"},{"name":"Department of Biology, Faculty of Sciences, Porto University, Rua do Campo Alegre, Porto 4069-007, Portugal"}]},{"given":"Micaela","family":"Vale","sequence":"additional","affiliation":[{"name":"CIIMAR\/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, 289, Porto 4050-123, Portugal"}]},{"given":"Marisa","family":"Freitas","sequence":"additional","affiliation":[{"name":"CIIMAR\/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, 289, Porto 4050-123, Portugal"},{"name":"Department of Biology, Faculty of Sciences, Porto University, Rua do Campo Alegre, Porto 4069-007, Portugal"},{"name":"CISA\/Research Centre in Environment and Health, School Health Technology of Oporto, Polytechnic Institute of Porto, Rua de Valente Perfeito, 322, Gaia 440-330, Portugal"}]},{"given":"Ana","family":"Regueiras","sequence":"additional","affiliation":[{"name":"CIIMAR\/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, 289, Porto 4050-123, Portugal"},{"name":"Department of Biology, Faculty of Sciences, Porto University, Rua do Campo Alegre, Porto 4069-007, Portugal"}]},{"given":"Agostinho","family":"Antunes","sequence":"additional","affiliation":[{"name":"CIIMAR\/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, 289, Porto 4050-123, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3585-2417","authenticated-orcid":false,"given":"Vitor","family":"Vasconcelos","sequence":"additional","affiliation":[{"name":"CIIMAR\/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, 289, Porto 4050-123, Portugal"},{"name":"Department of Biology, Faculty of Sciences, Porto University, Rua do Campo Alegre, Porto 4069-007, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2011,9,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"559","DOI":"10.1890\/1051-0761(1998)008[0559:NPOSWW]2.0.CO;2","article-title":"Nonpoint pollution of surface waters with phosphorus and nitrogen","volume":"8","author":"Carpenter","year":"1998","journal-title":"Ecol. Appl"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/S0269-7491(99)00091-3","article-title":"Eutrophication: Impacts of excess nutrient inputs on freshwater, marine, and terrestrial ecosystems","volume":"100","author":"Smith","year":"1999","journal-title":"Environ. Poll"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Chorus, I, and Bartram, J (1999). Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management, E & FN Spon.","DOI":"10.4324\/9780203478073"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Chorus, I, and Bartram, J (1999). Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management, E & FN Spoon.","DOI":"10.4324\/9780203478073"},{"key":"ref_5","unstructured":"Falconer, IR (1993). Algal Toxins in Seafood and Drinking Water, Academic Press."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1038\/scientificamerican0194-78","article-title":"The toxins of cyanobacteria","volume":"270","author":"Carmichael","year":"1994","journal-title":"Sci. Am"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1590\/S0100-879X1999000300001","article-title":"Cyanobacterial toxins in Portugal: Effects on aquatic animals and risk for human health","volume":"32","author":"Vasconcelos","year":"1999","journal-title":"Braz. J. Med. Biol. Res"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"295","DOI":"10.1127\/archiv-hydrobiol\/134\/1995\/295","article-title":"Isolation and characterization of microcystins (heptapeptide hepatotoxins) from Portuguese strains of Microcystis aeruginosa Kutz. emed Elekin","volume":"134","author":"Vasconcelos","year":"1995","journal-title":"Arch. Hydrobiol"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2377","DOI":"10.1016\/0043-1354(96)00152-2","article-title":"Microcystin (heptapeptide hepatotoxins) diversity in cyanobacterial blooms collected in Portuguese fresh waters","volume":"30","author":"Vasconcelos","year":"1996","journal-title":"Water Res"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/0014-5793(90)80245-E","article-title":"Cyanobacterial MC-LR is a potent and specific inhibitor of protein phosphatases 1 and 2A from both mammals and higher plants","volume":"264","author":"MacKintosh","year":"1990","journal-title":"FEBS Lett"},{"key":"ref_11","first-page":"93","article-title":"Toxicity evaluation of freshwater cyanobacterium Microcystis aeruginosa PCC 7806: II. Nephrotoxicity in rats","volume":"10","author":"Bhattacharya","year":"1997","journal-title":"Biomed. Environ. Sci"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1002\/tox.2530060207","article-title":"Tumor promotion and liver injury caused by oral consumption of cyanobacteria","volume":"6","author":"Falconer","year":"1991","journal-title":"Environ. Toxicol. Water Qual"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1453","DOI":"10.1016\/S0041-0101(97)00026-3","article-title":"Neoplastic nodular formation in mouse liver induced by repeated intraperitoneal injections of microcystin-LR","volume":"35","author":"Ito","year":"1997","journal-title":"Toxicon"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/j.taap.2004.09.005","article-title":"Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): A reasonable or misguided approach?","volume":"203","author":"Dietrich","year":"2005","journal-title":"Toxicol. Appl. Pharmacol"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1046\/j.1365-2958.1997.6131982.x","article-title":"Insertional mutagenesis of a peptide synthetase gene that is responsible for hepatotoxin production in the cyanobacterium Microcystis aeruginosa PCC 7806","volume":"26","author":"Dittmann","year":"1997","journal-title":"Mol. Microbiol"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"4089","DOI":"10.1128\/JB.181.13.4089-4097.1999","article-title":"Nonribosomal peptide synthesis and toxigenicity of cyanobacteria","volume":"181","author":"Neilan","year":"1999","journal-title":"J. Bacteriol"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"520","DOI":"10.1093\/oxfordjournals.jbchem.a022481","article-title":"Genetic analysis of the peptide synthetase genes for a cyclic heptapeptide microcystin in Microcystis spp","volume":"126","author":"Nishizawa","year":"1999","journal-title":"J Biochem"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"753","DOI":"10.1016\/S1074-5521(00)00021-1","article-title":"Structural organization of microcystin biosynthesis in Microcystis aeruginosa PCC7806: An integrated peptide-polyketide synthetase system","volume":"7","author":"Tillett","year":"2000","journal-title":"Chem. Biol"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Chorus, I, and Bartram, J (1999). Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring, and Management, E & FN Spon.","DOI":"10.4324\/9780203478073"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1007\/978-0-387-75865-7_24","article-title":"Emerging high throughput analyses of cyanobacterial toxins and toxic cyanobacteria","volume":"619","author":"Sivonen","year":"2008","journal-title":"Adv. Exp. Med. Biol"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1093\/oxfordjournals.jbchem.a022670","article-title":"Polyketide synthase gene coupled to the peptide synthetase module involved in the biosynthesis of the cyclic heptapeptide microcystin","volume":"127","author":"Nishizawa","year":"2000","journal-title":"J. Biochem"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1007\/s00203-003-0605-9","article-title":"PCR-based identification of microcystin-producing genotypes of different cyanobacterial genera","volume":"180","author":"Hisbergues","year":"2003","journal-title":"Arch. Microbiol"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"6101","DOI":"10.1128\/AEM.01058-06","article-title":"Detection of microcystin-producing cyanobacteria in finnish lakes with genus-specific microcystin synthetase gene E (mcyE) PCR and associations with environmental factors","volume":"72","author":"Rantala","year":"2006","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1111\/j.1574-6968.2006.00496.x","article-title":"Dynamics of microcystin-producing and non-microcystin-producing Microcystis populations is correlated with nitrate concentration in a Japanese lake","volume":"266","author":"Yoshida","year":"2007","journal-title":"FEMS Microbiol. Lett"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"812","DOI":"10.1021\/es801265f","article-title":"Quantification of toxic Microcystis and evaluation of its dominance ratio in blooms using real-time PCR","volume":"43","author":"Ha","year":"2008","journal-title":"Environ. Sci. Technol"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1016\/j.hal.2008.12.004","article-title":"Lake Erie Microcystis: Relationship between microcystin production, dynamics of genotypes and environmental parameters in a large lake","volume":"8","author":"Konopko","year":"2009","journal-title":"Harmful Algae"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4750","DOI":"10.1128\/AEM.02531-09","article-title":"Spatiotemporal variations in microcystin concentrations and in the proportions of microcystin-producing cells in several Microcystis aeruginosa populations","volume":"76","author":"Sabart","year":"2010","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"7289","DOI":"10.1128\/AEM.69.12.7289-7297.2003","article-title":"Quantitative real-time pcr for determination of microcystin synthetase E copy numbers for Microcystis and Anabaena in lakes","volume":"69","author":"Vaitomaa","year":"2003","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1111\/j.1574-6941.2001.tb00782.x","article-title":"Ecological and molecular investigations of cyanotoxin production","volume":"35","author":"Kaebernick","year":"2001","journal-title":"FEMS Microbiol. Ecol"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Chorus, I (2001). Cyanotoxins: Occurrence, Causes, Consequences, Springer-Verlag.","DOI":"10.1007\/978-3-642-59514-1"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1514","DOI":"10.1111\/j.1462-2920.2005.00858.x","article-title":"Contrasting microcystin production and cyanobacterial population dynamics in two Planktothrix-dominated freshwater lakes","volume":"7","author":"Janse","year":"2005","journal-title":"Environ. Microbiol"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.hal.2006.08.003","article-title":"Interactive influences of nutrient loading, zooplankton grazing, and microcystin synthetase gene expression on cyanobacterial bloom dynamics in a eutrophic New York lake","volume":"6","author":"Gobler","year":"2007","journal-title":"Harmful Algae"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"715","DOI":"10.1016\/j.hal.2009.02.004","article-title":"The effects of temperature and nutrients on the growth and dynamics of toxic and nontoxic strains of Microcystis during cyanobacterial blooms","volume":"8","author":"Davis","year":"2009","journal-title":"Harmful Algae"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3354\/ame048001","article-title":"Microcystis genotype succession in relation to microcystin concentrations in freshwater lakes","volume":"48","author":"Kardinaal","year":"2007","journal-title":"Aquat. Microb. Ecol"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2939","DOI":"10.1128\/AEM.02892-06","article-title":"Competition for light between toxic and nontoxic strains of the harmful cyanobacterium Microcystis","volume":"73","author":"Kardinaal","year":"2007","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"609","DOI":"10.4319\/lo.2007.52.2.0609","article-title":"Seasonal shifts in chemotype composition of Microcystis sp. communities in the pelagial and sediment of a shallow reservoir","volume":"52","author":"Welker","year":"2007","journal-title":"Limnol. Oceanogr"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1111\/j.1440-1770.2008.00362.x","article-title":"Virtual experimentation on cyanobacterial bloom dynamics and its application to a temperate reservoir (Torr\u00e3o, Portugal)","volume":"13","author":"Pereira","year":"2008","journal-title":"Lakes Reserv. Res. Manag"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"787","DOI":"10.1128\/AEM.69.2.787-795.2003","article-title":"The abundance of microcystin-producing genotypes correlates positively with colony size in Microcystis sp. and determines its microcystin net production in lake wannsee","volume":"69","author":"Kurmayer","year":"2003","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"6723","DOI":"10.1128\/AEM.69.11.6723-6730.2003","article-title":"Application of real-time PCR for quantification of microcystin genotypes in a population of the toxic cyanobacterium Microcystis sp","volume":"69","author":"Kurmayer","year":"2003","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1016\/j.hal.2008.10.010","article-title":"Diversity and dynamics of microcystin\u2014Producing cyanobacteria in China\u2019s third largest lake, Lake Taihu","volume":"8","author":"Ye","year":"2009","journal-title":"Harmful Algae"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"3202","DOI":"10.1128\/aem.55.12.3202-3207.1989","article-title":"Toxicity of Microcystis species isolated from natural blooms and purification of the toxin","volume":"55","author":"Ohtake","year":"1989","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1241","DOI":"10.1128\/aem.57.4.1241-1245.1991","article-title":"Toxicity and toxins of natural blooms and isolated strains of Microcystis spp. (cyanobacteria) and improved procedure for purification of cultures","volume":"57","author":"Shirai","year":"1991","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1007\/s002489900067","article-title":"Variation of MC content of cyanobacterial bloom sand isolated strains in Lake Grand-Lieu (France)","volume":"35","author":"Vezie","year":"1998","journal-title":"Microb. Ecol"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Chorus, I (2001). Cyanotoxins: Occurrences, Causes, Consequences, Springer Verlag.","DOI":"10.1007\/978-3-642-59514-1"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1038\/ismej.2008.121","article-title":"Spatiotemporal changes in the genetic diversity of a bloom-forming Microcystis aeruginosa (cyanobacteria) population","volume":"3","author":"Briand","year":"2009","journal-title":"ISME J"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1046\/j.1529-8817.2002.01138.x","article-title":"A PCR-based test to assess the potential for microcystin occurrence in channel catfish production ponds","volume":"38","author":"Nonneman","year":"2002","journal-title":"J. Phycol"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"3839","DOI":"10.1128\/AEM.02343-07","article-title":"Temporal variations in the dynamics of potentially microcystin-producing strains in a bloom-forming Planktothrix agardhii (cyanobacterium) population","volume":"74","author":"Briand","year":"2008","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Huisman, J, Matthijs, HCP, and Visser, PM (2005). Harmful Cyanobacteria, Springer.","DOI":"10.1007\/1-4020-3022-3"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"3269","DOI":"10.1128\/AEM.02240-07","article-title":"Ecological dynamics of the toxic bloom-forming cyanobacterium Microcystis aeruginosa and its cyanophages in freshwater","volume":"74","author":"Yoshida","year":"2008","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"790","DOI":"10.2144\/03344rr01","article-title":"Understanding bias in microbial community analysis techniques due to rrn operon copy number heterogeneity","volume":"34","author":"Crosby","year":"2003","journal-title":"BioTechniques"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"3327","DOI":"10.1128\/aem.63.8.3327-3332.1997","article-title":"PCR primers to amplify 16S rRNA genes from cyanobacteria","volume":"63","author":"Muyzer","year":"1997","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"693","DOI":"10.1099\/00207713-47-3-693","article-title":"rRNA sequences and evolutionary relationships among toxic and nontoxic cyanobacteria of the genus Microcystis","volume":"47","author":"Neilan","year":"1997","journal-title":"Int. J. Syst. Bacteriol"},{"key":"ref_53","first-page":"451","article-title":"Enzyme-linked immunosorbent assay for microcystins in blue-green algal blooms","volume":"73","author":"Chu","year":"1990","journal-title":"J. Assoc. Off. Anal. Chem"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"951","DOI":"10.1007\/s00253-009-1877-z","article-title":"Peptide diversity in strains of the cyanobacterium Microcystis aeruginosa isolated from Portuguese water supplies","volume":"82","author":"Martins","year":"2009","journal-title":"Appl. Microbiol. 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