Detection and quantification of microcystins from cyanobacteria strains isolated from reservoirs and ponds in Morocco

Abstract

In Morocco, the occurrence of toxic cyanobacteria blooms is confirmed in some water bodies used for recreational and/or as drinking water reservoirs. According to WHO recommendations, the establishment of a monitoring program for microcystins is a necessity. This paper presents toxicological studies of 19 toxic cyanobacteria strains of Microcystis, Synechocystis, Pseudanabaena, and Oscillatoria. These strains were isolated from various water bodies including natural lakes, reservoirs, and ponds located in central regions of Morocco. The isolation, culture, and biomass production of these strains was made on Z8 or BG13 media under laboratory controlled conditions. The hepatotoxicity of cyanobacterial lyophilized material was confirmed by mouse bioassays. The amount of microcystins produced by each strain was determined by the enzyme-linked immunosorbent assay (ELISA). The detection and identification of microcystin variants was performed by high performance liquid chromatography (HPLC) with photodiode array detection. Almost all strains showed medium to high toxicity, the estimated LD50 i.p. mice bioassay ranged between 28 to 350 mg/kg body weight. The concentrations of microcystins varied between 2.16 to 944 micrograms/g and 26.8 to 1884 micrograms/g dry weight determined by ELISA and HPLC, respectively. The screening of bloom-forming and microcystin producer cyanobacteria strains in these fresh water bodies leads us to propose the need for the establishment of a survey of cyanobacteria and a cyanotoxin-monitoring program.

Taxonomic diversity and toxicological assessment of Cyanobacteria in Moroccan inland waters

“…In fact, a species morphologically similar to Pseud. G. S25, determined as Pseudanabaena galeata, which was already isolated from the experimental wastewater stabilisation ponds of Marrakech, was confirmed as MCs producer (OUDRA et al, 2002b).…”

Molecular specificity and detection for Pseudanabaena (cyanobacteria) species based on rbcLX sequences

“…Oudra et al (2002) have detected microcystins occurring in Pseudanabaena strains in Morocco and determined that P. mucicola strains produced only one variant of microcystins and P. galeata produced two. The microcystin concentrations of the reported Pseudanabaena strains were much less than those of Microcystis strains.…”

“…Similar to many bloom-forming cyanobacteria, Pseudanabaena species produce hepatotoxic microcystin (Oudra et al, 2002), which is toxic to zoobenthos, fishes, animals, and humans. Some Pseudanabaena species also form muddy/musty odor substances (Wang et al, 2011), thereby directly causing problems in drinking water.…”

Hepatotoxic-Microcystins in Two Drinking Water Reservoirs in the Central Region of Ghana

“…These include Microcystis, Planktothrix and Anabaena, 1 Oscillatoria, 1,2 Radiocystis, 3 Anabaenopsis and Cylindrospermopsis, 1,4 Aphanothece, 5 Aphanocapsa, 6 Arthrospira, 7 Synechocystis, 8 and Scytonema. 9 Conditions that favour the growth of cyanobacteria are stable water column, warm water, high nutrient (phosphorus, nitrogen) concentrations and organic compounds such as humus and domestic waste, low concentration of nitrogen relative to phosphorus (N/P ratio) and high pH among others.…”