Lakes In Germany Research Articles

C19 The electrophysiology of adenosine: Clinical correlations to experimental observations

Toxic cyanobacterial blooms occurred in the years of 1992, 1993 and 1994 in a recreational lake in Germany (Leipzig). Each year, the bloom was dominated by Microcystis sp. and heaviest in September/October. Samples were collected from the surface as a scum and the toxicity was determined by the mouse bioassay (LD50 of the bloom sample 1992; 80 mg dry wt/kg body weight). Toxicity was primarily due to hepatotoxins of the microcystin class; microcystin-LR and microcystin-RR were found to be the major microcystins present in the samples of 1992, 1993, and 1994. Additionally, the bloom sample of 1993 contained microcystin-YR as a major hepatotoxin. Other microcystins were detected only in smaller amounts. The microcystins were identified applying common methods and included purification by a combination of Sephadex LH-20 gel filtration and anion exchange chromatography. The latter method proved to be applicable for the rapid separation of microcystin-RR from the other microcystins. Microcystin-YR revealed a UV absorbance maximum at 232 net in contrast to the other microcystins found.