Degradation of Pure Aflatoxins by Tetrahymena pyriformis.

Tetrahymena pyriformis W with nutrients, ca. 22 x 10 cells, decreased the concentration of aflatoxin B(1) 58% in 24 hr and 67% in 48 hr. An unknown, bright-blue fluorescent substance was produced, with intensity about one-half that of the unchanged B(1), with an R(f) of 0.52 compared with 0.59 for B(1) and 0.55 for B(2) on a thin-layer chromatography plate, and with an ultraviolet spectrum showing maxima of 253, 261, and 328 mmu. In a separate assay, the cells with nutrients did not degrade pure G(1). Starved, washed cells, ca. 11 x 10, decreased the concentration of B(1) 50% in 10 hr, 70% in 22 hr, and 75% in 30 hr, producing the same unknown component. Ethyl alcohol, 1.96% (v/v), decreased cell populations and size, but the cells remained actively motile in broth plus the alcohol for 96 hr. In 72 hr, neither toxin (ca. 2 ppm) in combination with ethyl alcohol had more inhibitory effect on cell numbers, with or without nutrients, than was produced by alcohol alone. Aflatoxin B(1) had no observed effect on the viability of the starved cells for 30 hr or on the nourished cells for 72 hr. There was no noticeable effect of G(1) on the starved cells in 30 hr or on the nourished cells in 48 hr. After 72 hr with G(1) plus nutrients, many of the cells were round with blisters, nonmotile, and apparently dead or dying.