A new culture-free microbiotest for routine detection of cyanobacterial toxins

The Thamnotoxkit F(TM) was evaluated for detecting cyanobacterial toxins. T his is a 24 hour bioassay using, as test organisms larvae of the freshwater anostracan crustacean Thamnocephalus platyurus hatched from cysts. Freeze- dried Microcystis aeruginosa samples from freshwaters throughout Hungary we re tested. Good correlation was obtained between the results of intraperito neal mouse bioassays and Thamnotoxkit F(TM) assays. The LC50's for purified microcystins- LR, -RR, and -YR ranged from 0.1 to 2.27 mu g per mL, respec tively in the Thamnotoxkit assay, The LC,, of laboratory cultures of Cylind rospermopsis raciborskii isolated from samples from Lake Balaton, was 0.574 mg lyophilized material per mt, in a four-laboratory trial, Although not d eveloped originally for detecting cyanobacterial toxins, the Thamnotoxkit F (TM) has good potential as an initial screening procedure for toxicity asse ssment of cyanobacterial scums and blooms in freshwaters. (C) 1999 by John Wiley & Sons, Inc.