title: Toxic cyanobacteria strains isolated from blooms in the Guadiana river (southwestern Spain).
abstract: This paper describes the occurrence of toxic cyanobacteria along the Guadiana River over its course between Mérida and Badajoz (Extremadura, Spain). Water sampling for phytoplankton quantification and toxin analysis was carried out regularly between 1999 and 2001 in six different locations, including two shallow, slow-flowing river sites, two streamed river sites and two drinking water reservoirs. The cyanobacterial community differed significantly between these locations, especially during the summer. The predominant genera were Microcystis, Oscillatoria, Aphanizomenon and Anabaena. Using an ELISA assay the total microcystin contents of natural water samples from the most eutrophic locations ranged from 0.10 - 21.86 microg mcyst-LR equivalent x L(-1) in Valdelacalzada and 0.10-11.3 microg mcyst-LR equivalent x L(-1) in Vitonogales, and a seasonal variation of toxin content was observed. The amount of microcystins produced by each strain was determined by ELISA assay and the detection and identification of microcystin variants of three toxic strains of Microcystis aeruginosa was performed by high performance liquid chromatography (HPLC). The analysis of microcystins of the cultured strains revealed that toxin production was variable among different strains of M. aeruginosa isolated either from different blooms or from the same bloom.
authors.affiliation: Area de Toxicología, Facultad de Farmacia, Universidad de Sevilla, 41012-Sevilla, Spain.
authors.forename: Isabel M
authors.initials: IM
authors.lastname: Moreno
authors.forename: Paulo
authors.initials: P
authors.lastname: Pereira
authors.forename: Susana
authors.initials: S
authors.lastname: Franca
authors.forename: Ana
authors.initials: A
authors.lastname: Cameán
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay; D010839:Phytoplankton / Q000382:microbiology; D045483:Rivers / Q000382:microbiology*; D012621:Seasons; D013030:Spain
chemical_list: D001427:Bacterial Toxins