Abstract
The occurrence of tetrodotoxin (TTX) in sediment from Lake Suwa, Japan, was confirmed by a tissue culture assay, high-performance liquid chromatography, and gas chromatography-mass spectrometry. Altogether, 17 TTX-producing bacteria belonging to five genera were isolated from Lake Suwa and Pond Inokasira. Our results indicate that TTX and TTX-producing bacteria occur even in freshwater environments.