• English
  • Português

Data of Thesis


Author: Cláudio Roberto Ribeiro Bobeda.

Title: Isolation, purification and characterization of microcystins (heptapeptides toxic) found in cyanobacterial blooms occurred in the reservoir Funil (Resende, RJ).

Year: 1993.    Full text (in Portuguese)


Several cyanobacteria species (blue-green algae) that I usually present mass development in fresh and brackish waters have been described as responsible for animal and human intoxication in many countries. Although there are no confirmed poisoning cases of animals or humans by cyanobacterial water blooms in Brazil, the increase of eutrophication in our drinking water supplies have permitted abundant growth of cyanobacterial toxic strains in these environments. This work studies the toxin production by a cyanobacterial water bloom which occurred at "Reservatório do Funil", Resende, Rio de Janeiro where Microcystis aeruginosa was the dominant specie. We Verified the occurrence of hepatotoxin in the phytoplanktonic samples and isolated and characterizated the hepatotoxins detected. Toxicity tests were carried out in mouse bioassays. The isolation and characterization of hepatotoxins were performed by isochratic HPLC, FABMS and FABMS/MS analysis. The hepatotoxicity of a water bloom had a positive linear correlation with M. aeruginosa cell percentages. Two hepatotoxin were isolated and characterizated as microcystin-LR and (D-Glu( OCH3)6jmicrocysti~- LR. This is the first time that the latter structure was identified from Microcystis aeruginosa.