ISOLATION AND TOXICITY OF CYLINDROSPERMOPSIS-RACIBORSKII FROM AN ORNAMENTAL LAKE

In Australia, the tropical/subtropical cyanobacterium Cylindrospermops is raciborskii forms substantial blooms in some drinking water supply reservoirs, rivers and recreational water bodies during the warmer mon ths of the year. This paper describes the isolation, culture and toxic ity characterisation of Cylindrospermopsis from a water bloom in a sma ll lake in NSW, Australia. The cyanobacterium grew as straight trichom es terminating with a characteristic heterocyst. The toxic alkaloid cy lindrospermopsin was separated and identified by high-performance liqu id chromatography at a concentration of 5.5 mg/g dry cells, 0.026 pg/c ell. Intraperitoneal injection of sonicated cells caused liver, kidney , intestinal and lung damage, with an LD(50) of 52 mg cells/kg mouse b ody weight at 24 hr, and 32 mg/kg at 7 days. The 24 hr mouse toxicity is not consistent with previous studies using pure cylindrospermopsin, and is suggestive of other toxic compounds in this isolate. (C) 1997 Elsevier Science Ltd.