pISSN 2508-1357, eISSN 2508-139X J Biomed Transl Res 2020;21(4):184-189 https://doi.org/10.12729/jbtr.2020.21.4.184 Received 17 Nov. 2020, Accepted 30 Nov. 2020 Cyanobacteria (blue green algae) blooms formed in natural water resources due to the environmental pollu- tion 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 evalu- ate 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 microcy- stin that affects aquatic ecosystems. Key words: cyanobacteria, microcystin, toxin, planarian, motility Introduction Cyanobacteria, also known as the blue-green algae, have been present on earth for billions of years. They have continued to evolve and adapt to the changing environ- mental conditions in the modern world. These cyano- bacteria are responsible for the oxygenic life of the earth due to their capability of photosynthesis [1]. They are known to thrive in both marine and fresh water sources. Evolution of the world has resulted in a negative adverse effect on the natural ecological systems. Anthropogenic activities, such as industrial revolution, improper agricul- tural activities, indiscriminate disposal of pollutants, and the construction of reservoirs [2], trigger proliferation of these bacteria. Moreover, global warming as well as the higher nutrient content and lower flow rate of the water resource, favors growth of these bacteria. Thus, blooming of these bacteria causes a striking greenish color in the water resource. It is very common to see blooming in tropical countries, since the environmental conditions are very conducive for cyanobacterial growth in temperate zones. Blooms of cyanobacteria are most prominent during late summer and early autumn, and may last for 2–4 months. This blooming adversely affects other living beings of the water resource such as aquatic fauna and flora, as well as humans using this water for their daily requirements [3–5]. Cyanobacteria belong to the gram-negative bacterial group, producing a vast range of toxic compounds as Original Article Effects of microcystin on the motility of planarians Young-Joo Yi 1†* , Yeon-Hwa Kim 2† , A. A. Dilki Indrachapa Adikari 1 , Seung-Tae Moon 1 , Sang-Myeong Lee 3* 1 Department of Agricultural Education, College of Education, Sunchon National University, Suncheon 57922, Korea 2 Division of Biotechnology, College of Environmental and Bioresource, Jeonbuk National University, Iksan 54596, Korea 3 Laboratory of Veterinary Virology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea † These authors contributed equally to this work. *Co-corresponding author: Young-Joo Yi Department of Agricultural Education, College of Education, Sunchon National University, Suncheon 57922, Korea Tel: +82-61-750-3352, E-mail: yiyj@scnu.ac.kr Sang-Myeong Lee Laboratory of Veterinary Virology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea Tel: +82-43-261-3356, E-mail: smlee@chungbuk.ac.kr