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(470) Monitoring of peptide cyanotoxins and potentially toxic cyanobacteria in a Spanish drinking water supply. del Campo, Francisca1, Carrasco, David1, Fernández-Valiente, Eduardo1, Foronda, David1, Leganés, Francisco1, Padilla, Carlos1, Quesada, Antonio1, Sanchis, Daniel1, Sanz-Alférez, Soledad1, 1 ABSTRACT- Cyanobacteria are frequent contaminants in recreational and drinking water supplies, and can become a serious threat to health when they are toxic and overgrow, usually as blooms. The most widespread cyanotoxins are cyclic oligopeptides, whose synthesis takes place through a nonribosomal pathway. Among these cyanopeptide toxins (CPTs) microcystins (MCs) are the most usual. The last step of MC synthesis is catalysed by microcystin synthetase, a complex enzymatic system formed by a polyketide synthase and a peptide synthetase (PS). CPTs stand conventional water treatment, such as chlorination; therefore, an early diagnosis of potentially CPT producing cyanobacteria should greatly help water companies to design in time the appropriate water treatment for CPT decontamination. We have started a pioneer research in Spain by monitoring during a 4-year period in a drinking water reservoir cyanobacteria biomass, cyanobacteria strains, as well as the content and class of CPTs in cyanobiomass. A special effort has been done to molecularly identify potential CPT-producing Microcystis strains, by analysing PCR amplified DNA fragments that correspond to conserved sequences (nucleotide binding region) of PS genes. The DNA used as template was obtained from isolated strains or directly from blooms if these were apparently formed by only one strain. In summary, our data show: i) a great variability during the 4 years both in cyanobacteria biomass and CPT content; ii) a recurrent seasonal cyanobacteria succession; iii) no correlation between cyanobiomass and CPT content; and iv) frequent presence of conserved PS nucleotide sequences in Microcystis strains albeit CPTs being negligible in these strains. Key words: drinking water peptidetoxins, cyanobacteria, molecular toxic cyanobacteria identification , microcystis |
