Chromosomal response of insect and mammalian cells to streptonigrin: a comparative study.

We assessed the chromosomal response of insect (mosquito, Aedes albopictus) and mammalian (Chinese hamster ovary, CHO) cells to streptonigrin (SN). Both types of cells were pulse-treated for 20 min with increasing doses of SN and the frequency of chromosome aberrations and sister chromatid exchanges (SCEs) for each SN dose was determined. Our results show that the SN doses inducing remarkable chromosome damage (expressed as frequency of aberrations per cell and per chromosome) in CHO cells fail to produce a significant increase of aberrations in mosquito chromosomes. Moreover, CHO cells exhibited a dose-dependent increase in SCEs which was not observed in mosquito cells. Our results show that while mammalian cells are very sensitive, insect cells are very resistant to SN at the chromosome level. It is possible that variations in the chromatin fibril structure and in the intracellular antioxidant pool may be responsible for the differential response of insect and mammalian chromosomes to SN.