| Summary: | 碩士 === 國立清華大學 === 輻射生物研究所 === 81 === A modified cell suicide method was applied to solate the sodium
arsenite ( SA ) sensitiveutants from the ethylnitrosourea ( ENU
) mutagenized Chinese hamster ovary (CHO-K1) cells in this
study. Totally 197 candidates were picked after screening 3*106
ENU-mutagenized cells and 14 sensitive mutants were obtained
from three separated experiments. The most two sensitive
sublines, B26 and D21, were about 3- and 7-fold more sensitive
to SA than their parental CHO-K1 cells respectively, as
estimated from LD50 values. Both the glutathione ( GSH ) level
and glutathione s-transferase ( GST ) activity in B26 and D21
cells were equal to those in their parental cells. The D21
cells accumulated more arsenic than CHO-K1 cells did,
indicating that the sensitization to SA was related to an
increased arsenic accumulation in D21 cells after SA treatment.
The D21 cells were markedly cross-sensitive to sodium arsenate
and mercury chloride ( LD50 values are one-seventh and one-
third LD50 values of wild type ). In addition, the D21 cells
showed 1.5-2.0- fold of sensitivity to DNA damage agents ( ENU,
cisplatin and r-ray ) and metal compounds ( ZnSO4 and CdCl2 ).
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