Mortality and toxin bioaccumulation in Bufo marinus following exposure to Cylindrospermopsis raciborskii cell extracts and live cultures

Cylindrospermopsis raciborskii is a cyanobacterium responsible for the production of the toxin, cylindrospermopsin (CYN). Tadpoles of the cane toad Bufo marinus were exposed to freeze-thawed whole cell extracts or live cultures of C. raciborskii containing maximum CYN concentrations of 400 micrograms per litre or 232 micrograms per litre, respectively. Exposure to live culture treatment solutions resulted in up to 66% mortality of B. marinus, whereas tadpoles exposed to whole cell extracts containing similar toxin concentrations survived. Decreases in relative growth rates and time spent for swimming were recorded from tadpoles during both types of exposure regimes. Bioconcentration of CYN was not evident following exposure to whole cell extracts containing extracellular toxin. In contrast exposure to live cultures, which contained cell-bound toxin, resulted in maximum average tissue concentrations of 895 micrograms of free-CYN per kg fresh weight. This is the first investigation of C. raciborskii exposure effectsand toxin bioaccumulation in the developmental stages of an amphibian.