A SPECIFIC ULTRAVIOLET ABSORBANCE BAND OFMICROCYSTIS AERUGINOSATOXINS

SUMMARY It could be shown that toxic fractions of Microcystis aeruginosa extracts always had a 240 nm absorbance band, There was a linear relationship between toxicity and UV absorbance at 240 nm of extracts from different isolates of Nicrocystis. One ml of a solution with an absorbance of −1,0 at 240 nm (10 mm pathlength) had sufficient toxin to kill 19 mice (~20 g). Because only the toxic fractions of Microcystis extracts had a higher absorbance at 240 than at 210 nm monitoring at these wavelengths immediately identified toxic fractions. In partially purified extracts 240 nm absorbance may be used in stead of mouse assay to determine toxicity.