The effects of aflatoxin B₁, citrinin, and ochratoxin A on amino acid uptake and incorporation by cucumber

Both aflatoxin B 1 and citrinin, in light and darkness, inhibited leucine uptake and its incorporation into protein by cucumber cotyledon disks. Aflatoxin was more inhibitory in the light and both toxins showed increased inhibition with increasing concentration. At a concentration of 50 μg/ml, citrinin was more inhibitory to amino acid absorption than aflatoxin. Time-course studies showed that a pretreatment time of at least 2 h was necessary with aflatoxin to affect the subsequent incorporation of leucine; citrinin, on the other hand, was inhibitory when it was supplied together with the 14 C-leucine. In darkness, ochratoxin A at 10, 50, and 100 μg/ml enhanced leucine uptake but did not affect its incorporation into protein.