CIDCA   05380
CENTRO DE INVESTIGACION Y DESARROLLO EN CRIOTECNOLOGIA DE ALIMENTOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Chracterization of cyanobacteria present in Yacyretá Blooms (Argentina)
Autor/es:
2. LLANO V, VERON C, DOMINGUEZ S, CANEO M, ANDRINOLO D, MEICHTRY N, SALERNO G.
Lugar:
Rio de janeiro Brasil
Reunión:
Congreso; VII International Conference on Cyanobacteria; 2007
Institución organizadora:
UFRJ
Resumen:
Harmful cyanobacterial blooms have been increasing during the last decade in South America. Particularly, in
the Paraná River an enhancement in the density and permanence of cyanobacterial blooms has been registered
in the last years, associated to eutrophication processes. It is also evident that the number of cyanobacterial
species, which may produce toxins, is increasing in the region, as it is the number and variety of toxins. Since
the summer of 2004, at the Yacyretá dam, located on the Alto Paraná (27° 28´ S, 56° 44´O), an increase of the
frequency of blooming was observed. Consequently, the isolation and characterisation of cyanobacteria present
in each episode and the cyanotoxins they produce in a systematic program is of relevance. The present work
shows the first results of an integrated study comparing the cellular density, toxin levels, physical parameters
as well as microscopical and molecular identification of cyanobacterium species present in blooms. A seasonal
sampling was made in the left shore of the Yacyretá dam that exhibited more favorable conditions for its
development. Cyanobacteria, represented by 11 different taxa, were more abundant in summer and spring. The
density changed between 0 to 49,192 cell per ml, being Microcystis aeruginosa the most abundant and the
only producer of blooms. Closely related genotypes of M. aeruginosa were identified using PCR methodology
by amplification of the PC-ING and rRNA-ITS regions. Cyanobacterial communities showed different relative
abundance between bloom stages. Also, identification and quantification of cyanotoxins were made by HPLC
(HP 1100, C18 column, 238 nm UV detection), comparing the samples with analytical standards for RR, LR,
XR and YR microcystines, and nodularines. Toxin production is mainly represented by microcystines.
Supported by ANPCyT (PICT 2004 Nº 21227/53), CONICET (PID 6105), UNaM, Yacyretá, and FIBA.Microcystis aeruginosa the most abundant and the
only producer of blooms. Closely related genotypes of M. aeruginosa were identified using PCR methodology
by amplification of the PC-ING and rRNA-ITS regions. Cyanobacterial communities showed different relative
abundance between bloom stages. Also, identification and quantification of cyanotoxins were made by HPLC
(HP 1100, C18 column, 238 nm UV detection), comparing the samples with analytical standards for RR, LR,
XR and YR microcystines, and nodularines. Toxin production is mainly represented by microcystines.
Supported by ANPCyT (PICT 2004 Nº 21227/53), CONICET (PID 6105), UNaM, Yacyretá, and FIBA.M. aeruginosa were identified using PCR methodology
by amplification of the PC-ING and rRNA-ITS regions. Cyanobacterial communities showed different relative
abundance between bloom stages. Also, identification and quantification of cyanotoxins were made by HPLC
(HP 1100, C18 column, 238 nm UV detection), comparing the samples with analytical standards for RR, LR,
XR and YR microcystines, and nodularines. Toxin production is mainly represented by microcystines.
Supported by ANPCyT (PICT 2004 Nº 21227/53), CONICET (PID 6105), UNaM, Yacyretá, and FIBA.