Microcystins in South American aquatic ecosystems: Occurrence, toxicity and toxicological assays

Abstract

The acute poisoning of chronic renal patients during hemodialysis sessions in 1996 in Caruaru City (Pernambuco State, Brazil) stimulated an intensive search for the cause of this severe complication. This search culminated in the identification of microcystins (MC), hepatotoxic cyclic heptapeptides produced by cyanobacteria, as the causative agents. More than ten years later, additional research data provides us with a better understanding of the factors related to cyanobacterial bloom occurrence and production of MC in Brazil and other South American countries. The contamination of water bodies and formation of toxic blooms remains a very serious concern, especially in countries in which surface water is used as the main source for human consumption. The purpose of this review is to highlight the discoveries of the past 15 years that have brought South American researchers to their current level of understanding of toxic cyanobacteria species and that have contributed to their knowledge of factors related to MC production, mechanisms of action and consequences for human health and the environment.

Tropical cyanobacterial blooms: a review of prevalence, problem taxa, toxins and influencing environmental factors

“…This increase was probably motivated by the two incidents that led to human fatalities in 1988 and 1996 (Teixeira et al, 1993;Domingos et al, 1999;Carmichael et al, 2001;Azevedo et al, 2002;Molica 2002). Few studies have been conducted in other countries such as Panama and Colombia (Bartram et al, 1999;Dorr et al, 2010).…”

“…Since that incident some studies have been carried out on several reservoirs in South and Central America documenting blooms and progenitor species (Díaz-Pardo et al, 1998;Lind and Davalos-Lind, 2002;Ramirez et al, 2002;Bittencourt-Oliveira et al, 2005;Frias et al, 2006;Merino-Ibarra et al, 2007;Berry and Lind, 2010;Vasconcelos et al, 2010;Rejmánková et al, 2011). A review by Dorr et al (2010) revealed that there has been increased cyanobacterial bloom occurrence in water bodies in South America requiring better methods for screening and testing of cyanobacterial toxins.…”

Occurrence of toxic blooms of Microcystis aeruginosa in a central Chilean (36° Lat. S) urban lake

“…In South America, the events of toxic cyanobacterial blooms have been under estimated and poorly documented [20]. One of the most common genera reported in blooms is Microcystis, responsible for the intoxication of 131 people and 52 deaths in Caruaru city, Brazil [21], as well as blooms in other areas of Brazil.…”

Mitochondrial electron transport chain is involved in microcystin-RR induced tobacco BY-2 cells apoptosis

“…Outbreaks of cyanobacterial (especially Microcystis aeruginosa) blooms caused by eutrophication have been a worldwide threat to aquatic ecosystems and human health (Dörr et al, 2010). Microcystins (MCs) are a family of monocyclic nonribosomal peptides produced by cyanobacteria.…”