UBC Theses and Dissertations
Cytotoxic responses to aflatoxins on fertilized oyster eggs, Crassostrea gigas Park, Hyun Chul
Aflatoxins B₁, B₂, G₁ and G₂ and a crude preparation of freshly prepared aflatoxin produced by Aspergillus parasiticus NRRL 2999 were added to the fertilized oyster, Crassostrea gigas, eggs. The addition of 2, 3, 4 and 5 ug/ml of aflatoxin B₁, inhibited the first cell division of fertilized oyster eggs by 10, 30, 70 and 90 percent, respectively. First cell division did not appear to be inhibited by 5 ug/ml of either aflatoxins B₂,G₁ or G₂ A change in the fine structure of the fertilized oyster eggs was observed following the addition of 5 ug/ml of aflatoxin B₁. Visible changes or alterations in the aflatoxin treated zygotes were not readily detectible in the electron micrographs except for the segregation of the fibrillar and granular components of the nucleolus, an apparent decrease of the vesicles surrounding the cisternal rough endoplasmic reticulum, and the final inhibition of the mitotic division process before first cell division. The data is consistant with the observed cytotoxic effects suggesting an inhibition at the cell DNA replication, RNA transcription and protein translational levels in the aflatoxin B₁ treated oyster zygotes.
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