Effects of microcystin on the motility of planarians

Abstract

Cyanobacteria (blue green algae) blooms formed in natural water resources due to the environmental pollution produce toxic compounds as secondary metabolites, causing health hazards to both humans and other living beings. Microcystin is a well-known toxin produced by cynobacteria. The present study was undertaken to evaluate varying concentrations and exposure times of two different forms of microcystin, viz., -LR (MCLR) and -LA (MCLA), on the motility and seizure-like behavior of planarian (Dugesia japonica). Compared to control, reduced motility was observed in both the MCLR or MCLA treated groups, but did not differ significantly with increasing concentrations of microcystin. However, the number of seizure-like behaviors were increased dose-dependently in planarian exposed to MLCR or MCLA. Exposure time to microcystine also affected the motility and seizure-like behaviors of planarians; 24 hrs incubation with MCLR, and 48 and 96 hrs exposure to MCLA, showed significantly (p<0.05) lower motility, as compared to the control. Assessing regeneration of the planarians revealed the simultaneous completion of eye formation at day 9 in planarians incubated in the absence or presence of MCLR or MCLA, thereby indicating that exposure to microcystin has no effect on the process. In conclusion, we determined that exposure to microcystins resulted in decrease in the number of motility, and induced abnormal behavior pattern in planarians. Further studies are required to identify the toxicity of microcystin that affects aquatic ecosystems.