2. Microcystin-RR Like Toxin Identified in the Cyanobacterium <i>Anabaena flos-aquae</i> Strain CCAP 1403/13B Culture

Abstract

Cyanobacteria abound in freshwaters in Ghana, including those used for the supply of drinking water. However, there have been no studies on their toxicity, the toxins they produce and their attending public health effects. As part of research activities to identify cyanobacteria and cyanotoxins associated with four reservoirs (Weija, Kpong, Owabi and Barekese), used for the production of drinking water in Ghana, Anabaena flos-aquae, a toxic cyanobacterium, was cultured in the laboratory with the objective of identifying potential cyanotoxins that may be associated with some of the cyanobacteria commonly found in Ghanaian waters. Cultures were kept in a
growth chamber with continuous illumination at 20 ìmol photon/m2/s and constant aeration at a temperature of 25 oC. High pressure liquid chromatography (HPLC) analysis of extract from the culture of Anabaena flos-aquae strain CCAP 1403/13B produced a toxin with a retention time similar to microcystin-RR external standard. The concentration of microcystin-RR quantified from Anabaena flos-aquae was 10.6 ìg/g DW. The biomass of lyophilized cells extracted was 52 mg. Anabaena flos-aquae is mainly known to produce neurotoxins, notably anatoxin-a and anatoxin-a(s). Anabaena and Microcystis were reported to be responsible for the lethal poisoning of over 2000 people in Bahia, Brazil through drinking water which resulted in the death of 88 children from
gastro-enteritis over a period of 42 days.