The effect of non-ionic surfactants on the SOS-inducing potency of 4-nitroquinoline-1-oxide in Escherichia coli PQ37.

Various non-ionic surfactants affect the SOS-inducing potency (SOSIP) of the model genotoxin, 4-nitroquinoline-1-oxide, in Escherichia coli PQ37 to varying degrees, as measured by an automated version of the SOS chromotest. While there is little effect on the SOSIP value and other test parameters from Tween 20 and 80 and, with some reservation, Triton X305 and Tyloxapol, over the critical micelle concentration range, the SOSIP value increases in the presence of comparable concentrations of Triton X15, 45 and 100. A possible dependence of the tester strain's beta-galactosidase production and its growth inhibition on the HLB of the non-ionic surfactants added is discussed.