Hepatosplenomegaly and phytotoxicity of a planktonic cyanobacterium Nostoc sp. BHU001 isolated from agricultural pond

Abstract

Nostoc sp. BHU001, a planktonic cyanobacterium isolated from an agricultural pond in India, was examined for its toxicity. Mice, administered intraperitoneally with Nostoc sp. BHU001 crude extract (50 mg kg -1 body weight) died at 4.5 h. Examination of liver and spleen showed microcystin (MC)-like symptoms. Serum enzyme aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities increased by 1.6-1.8 and 2.6-3.0-folds, respectively at 50 and 100 mg crude extract kg -1 body weight. Thin layer chromatography of the crude extract produced five bands (N-1 to N-5). UV absorption maxima of band N-4 corresponded to that of standard microcystin-LR. Further analysis of the band N-4 by highperformance liquid chromatography gave a retention time (R t ) of 4.61 min similar to that of standard microcystin-LR (LR stands for lysine and arginine). Total MC content was quantified by enzyme-linked immunosorbent assay, and was 189.9 lg g -1 of crude extract, 9.8 lg l -1 of spent medium and 5.5 lg l -1 of pond water. Exposure of rice (Oryza sativa var. Sonam) seeds to the crude extract did not affect their germination, but inhibited the root and shoot growth of seedlings by 27.3 and 42.89 folds at 3 mg ml -1 crude extract, respectively.Keywords ALT and AST serum enzymes Á Cyanotoxins Á ELISA Á HPLC Á Liver and spleen histology Á Microcystins Á TLC

Physiological evidence indicates microcystin-LR to be a part of quantitative chemical defense system

“…BHU001 culture. The MC-LR was collected and concentrated by lyophilization (Bajpai et al 2009b). The dried MC-LR was dissolved in distilled water and used for experimentation.…”