Mutagenicity of N,N'-dimethylurea and methylamine hydrochloride in the Ames Salmonella/microsome test: absence of mutagenic response.
Methyl isocyanate (MIC) in aqueous solution forms methylamine (MA) and N,N'-dimethylurea (DMU). MA in buffered system further converts into its salt form, methylamine hydrochloride (MAH). Therefore, MAH and DMU were evaluated for their mutagenic activity in the in vitro Ames Salmonella/microsome mutagenicity test. The liquid preincubation protocol was followed, using tester strains TA98, TA100 and TA104 of Salmonella typhimurium, in the presence of 0, 5, 15 and 30% Aroclor 1254-induced rat liver S9 mixture. DMU and MAH did not induce a mutagenic response in any of the tester strains, both in the presence and in the absence of S9 mixture. The results therefore confirm that MIC in its native form or as its unknown metabolites is responsible for the mutagenic activity reported earlier by us in the his tester strains TA100 and TA104 of Salmonella typhimurium (Mutation Res., 204 (1988) 123-129) and not due to its hydrolysis products, MA or DMU.
Meshram
G P
GP
Division of Microbiology, Defence Research and Development Establishment, Gwalior, India.
Malini
R P
RP
Rao
K M
KM
D003485:Cyanates / Q000633:toxicity*; D004789:Enzyme Activation; D017953:Isocyanates; D008110:Liver Extracts; D008744:Methylamines / Q000633:toxicity*; D008782:Methylurea Compounds / Q000633:toxicity*; D008826:Microbial Sensitivity Tests; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D016296:Mutagenesis; D009152:Mutagenicity Tests / Q000379:methods; D012486:Salmonella typhimurium / Q000187:drug effects
D003485:Cyanates; D017953:Isocyanates; D008110:Liver Extracts; D008744:Methylamines; D008782:Methylurea Compounds; C027451:methylamine; C008461:methyl isocyanate; C018275:1,1-dimethylurea