Uptake and metabolism of the Cyanobacterial Hepatotoxin Microcystin-RR by Spirodela intermedia from Brazil.

Abstract

Spirodela intermedia was exposed to low (10 µg L-1) and high concentration (100 µg L-1) of microcystin-RR (Arginin-Arginin) over aperiod of two weeks. Depuration in the water phase, as weIl as uptake in the plant was determined using HPLC with photodiode array (PDA) detection. After the toxin uptake, metabolism of microcystin-RR occuored resulting in the formation of a glutathione conjugate. This conjugate was further processed yielding in a cysteine conjugate, a weIl known breakdown product in the biotransformation pathway of microcystins. The results indicate the uptake, accumulation and metabolism of microcystin-RR in a surface floating aquatic plant and raise the possibilities, to use these plants within water purification or toxin removal. Further implication on aquatic ecosystem and the transfer of toxin in the food web might occur and needs more investigation.