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ความรู้ทั่วไปเกี่ยวกับสิ่งเป็นพิษความรู้ทั่วไปที่นักวิชาการควรทราบพิษวิทยาคลีนิคก้าวทันโลกข้อมูลบริการแหล่งข้อมูลที่เกี่ยวข้อง
 
   
IDENTIFICATION AND CYTOTOXICITY OF MICROCYSTIN-LR ISOLATED FROM MICROCYSTIS AERUGINOSA  KÜTZ. IN HUAY YUAK RESERVOIR, CHIANG MAI PROVINCE

SORAYA AROONVILAIRAT1, WERAWAN RUANGYUTTIKARN1, JEERAPORN PEKKOH2, XIAO YUN SHEN3, WASANTHA WICKRAMASINGHE3, GLEN SHAW3, YUWADEE PEERAPORNPISAL2

1Division of Toxicology, Department of Forensic Medicine, Faculty of Medicine,
2 Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
3 National Research Centre for Environmental Toxicology, Brisbane, Queensland, Australia
E-mail : saroonv@hotmail.com


      Microcystin-LR is a potent hepatotoxin produced by several species of blue-green algae or cyanobacteria, especially Microcystis aeruginosa  KÜtz., which causes serious water quality problems. Microcystin-LR was identified and analyzed in cyanobacterial cells collected from Huay Yuak reservoir in Chiang Mai province. The cytotoxicity of microcystin-LR was investigated on primary cultured rat hepatocytes using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. M. aeruginosa  was also cultured in MA medium at 25 °C under a 14:10 h light/dark cycle with daylight fluorescent density about 30 mmol/m2/s for one month in order to investigate the relationship between the microcystin-LR concentrations in the cyanobacterial cells and the culture media. Microcystin-LR was determined by high performance liquid chromatography (HPLC), with a UV detector at 238 nm using a C18 column and linear gradient elution of 30-70% acetonitrile (0.05% trifluoroacetic acid) in 40 min. The retention time of microcystin-LR was 11.85 min. The quantity of microcystin-LR was 0.14 mg/g of dried cells. Confirmatory identification of microcystin-LR was analyzed under optimized liquid chromatography-tandem mass spectrometry (LC-MS-MS) conditions. Microcystin-LR exhibited toxic effects on primary cultured rat hepatocytes with an IC50 of 10.34 ng/mL at 24 h incubation. The logarithmic and stationary growth phases of M. aeruginosa  cultures showed that the microcystin-LR concentrations in the cynobacterial cells correlated negatively with the microcystin-LR concentrations in the culture media. This study indicated that microcystin-LR found in cyanobacterial samples from Huay Yuak reservoir had high toxicity on rat hepatocytes. Therefore, exposure to microcystin-LR contaminated in the water could result in cellular damage and harm for people who use this reservoir.

ที่มา ABSTRACT นำเสนอที่ การประชุมวิชาการสมาคมพิษวิทยาแห่งประเทศไทย ประจำปี 2547 อาหารกับความปลอดภัย วันศุกร์ที่ 17 ธันวาคม 2547 โรงแรมมิราเคิลแกรนด์ กรุงเทพฯ