科研之友
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摘要
Microcystis is one of the most common bloom-forming cyanobacteria genera in diverse ecosystems. More than 80% of its strains are toxic, mainly due to their ability to produce metabolites known as microcystins (MC). Here we report on a M. aeruginosa bloom that appeared in the summer of 2001 at a site of the Rio de la Plata, within the city of Buenos Aires. The symptoms in mice indicated that the bloom was hepatotoxic. LC-PDA analysis revealed a similar high concentration (0.9-1 mg g(-1) d w) of just one MC in the bloom biomass during the 3-month study period. During this period most of the MC (ca. 98 %) was found intracellularly, and the content remained almost the same. The molecular mass of the bloom MC was 1036 Da, as deduced from LC-ESI-MS data. Fragment ion analysis by LC-IT-MS-MS allowed identifying 6 out of the 7 amino acids, as well as their position in the molecule. The molecular mass of the unidentified amino acid residue was 155 Da. According to the data obtained, the MC under study was MC-XR, X representing the unidentified amino acid. This is the first report both on the characterisation of MCs in an urban site of the Rio de la Plata waters, and on an Argentinean bloom exhibiting only one MC variant.
- 出版日期2011
