Effect of pH on the mutagenic and killing potencies of ICR-170 in ad- 3 tests of Neurospora crassa.
Whong-Z; Ong-M; Brockman-HE
Mutat Res 1985 Jan-Feb; 142(1-2):19-22
The effect of pH on the mutagenic actions of 2-methoxy-6-chloro-9-(3- (ethyl-2-chloroethyl)-aminopropylamino)acridine dihydrochloride (13441957) (ICR-170) was examined. Reversion from adenine dependence to independence was studied using adenine-3 (ad-3) forward and reverse mutation tests with ad-3 mutant 12-9-17. Neurospora-crassa conidia were treated with 5 micrograms/milliliter ICR-170 at pHs of 3, 5, 7, 9 and 11 for 3 hours. Percent survival and reversion frequencies were determined. Absence of ICR-170 was associated with a viability decline at pH 11; ICR-170 addition resulted in decreased survival as pH increased from 5 to 9. Reversion frequency was low at pH 5 but substantially increased at pH 7 and particularly at pH 9. Examination of forward mutation at the ad-3 region demonstrated no changes in survival or ad-3 mutation frequency at different pHs in the absence of ICR-170; however, the addition of ICR-170 resulted in increased killing and ad-3 mutation at pHs of 7 and 9. Uptake studies demonstrated that uptake of ICR- 170 by 12-9-17 conidia rapidly increased as pH increased from 5 to 9. The authors attributed the effect of pH on the mutagenic nature of ICR-170 partially to pH's effect on ICR-170 uptake by Neurospora conidia.
NIOSH-Author; In-vitro-study; Mutagenicity; Toxic-effects; Acridines; Acid-base-equilibrium; Survival-rate; Gene-mutation