PRODUCTION OF ROTENONE-INACTIVATING SUBSTANCE(S) BY ROTENONE-RESISTANT INSECT-CELL LINE

In a previous paper, we showed that a cell line derived from hemocytes of the cabbage armyworm, Mamestra brassicae (R-cell) was a thousand t imes as resistant to rotenone as that from ovaries of the same species (S-cell). The S-cells were killed by rotenone at concentrations highe r than 10(-9) M, while R-cells at higher than 10(-6) M. When the R-cel ls were cultured in the medium containing 10(-9) M rotenone, the abili ty of rotenone to kill the S-cells was lost in the used medium. Also, when rotenone was incubated in the medium conditioned with R-cells, it lost its cell killing activity. It became evident that rotenone-inact ivating substance(s) were produced in cells and stored in water-solubl e form or liberated into the medium. The substance(s) were inactivated by heat treatment.