Microcystis aeruginosa CAAT 2005 strain from Argentina: phylogenetic and toxicological caracterization.

ROSSO LORENA; SEDAN DANIELA; KOLMAN MARIA; CAIXACH JOSEP; FLORES CINTIA; SALERNO GRACIELA; GIANNUZZI LEDA; ANDRINOLO DARÍO

Pilanesberg

Congreso; 9TH INTERNATIONAL CONFERENCE ON TOXIC CYANOBACTERIA; 2013

Nelson Mandela Metropolitan University

Background and aims: Research in cyanobacteria area, as tools development for bloom mitigation or ecotoxicological studies, is usually based on studies conducted with a few culture strains maintained in some worldwide laboratories. The information on cyanobacteria and cyanotoxins present in South America is scarce and fragmented. In Argentina, there are only a few reports even when toxic cyanobacteria have been identified in 13 of 24 provinces in the country. To understand the cyanobacteria phenomenon is essential obtain cultures of Microcystis strains present in our region to conduct physiological, genetic, taxonomic and toxin production studies. The aim of this work is develop a phylogenetic and Toxicological characterization for the first strain of Microcystis aeruginosa Argentina (CAAT2005) isolated from the environment and maintained under culture conditions. Methods: Microcystis aeruginosa CAAT 2005 was growth in BG11 medium, cycles of light / dark 14-10 hs, 28 ºC and 60 µE.m-2s-1 photon flux density. On this culture cell counts and total microcystins quantification were determined. Cuantitative cromatographic analysis was performed by HPLC-DAD and [D-Leu 1] microcystin-LR identification was carried out with LC/ESI-HRMS. Number of cel/ml and [D-Leu 1] microcystin-LR production were modelled using Gompertz equation. Phylogenetic analysis was carried out by studying the cpcBA-IGS sequences and comparing them with NCBI databases. Results and conclusions: Phylogenetic analysis based on cpcBA-IGS sequence confirms the identity given grouping with known sequences of strains of M. aeruginosa. CAAT2005 Microcystis strain expresses a microcystin variant, frequent in Del Plata and Salado basin samples, which has been identified as [D-Leu1] Mcyst ?LR, C52H80N10O12, M+H]+ : 1037.6035, (1.145 ppm) and has been discarded [ADMAdda5] Mcyst-Lhar C51H76N10O13, M+H]+ 1037.5671 (-2.732 ppm) by both the errors/ppm as isotopic pattern concordance. This is the first strain of toxigenic cyanobacteria maintained in controlled growing conditions in Argentina and adds to Microcystis RST9501 strain isolated from Los Patos lagoon in Brazil. This work provides the basis for technological development and production of analytical standards of toxins present in our region.