Streptomyces fradiae expressed an adaptive response to treatment with small doses of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) that caused a reduction in mutagenesis by treatment with larger doses of MNNG. Treatment of S. fradiae with high levels of MNNG in the presence of chloramphenicol caused enhancement of mutagenesis, independent of the adaptive response.

Transgenic mouse assays, such as MutaTMMouse, provide a method to predict the potential target organ carcinogenicity of chemical compounds. As part of a validation study, the effects of the direct-acting mutagens, JV-methylW-nitro-N-nitrosoguanidine (MNNG) and 1-chloromethylpyrene (CMP), were investigated for gene mutation in the tissues of MutaTMMice after a single oral or topical exposure. MN...

We have observed a reproducible mitochondrial mutational spectrum in the MT1 human lymphoblastoid line treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The MNNG spectrum was distinct from the spontaneous mutational spectrum. However, our ability to observe MNNG-induced mitochondrial mutations above the high level of accumulated spontaneous mutations was dependent on the MT1 phenotype. ...

Equitoxic concentrations of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and methyl methanesulfonate (MeMes) produced different frequencies of 8-azaguanine-resistant mutants and different amounts of N7-methylguanine, O6-methylguanine (m6G), and N3-methyladenine in the DNA of V79 Chinese hamster cells. Thus, neither the cytotoxicities nor the mutagenicities of these methylating agents could be at...

The human colon tumor cell line HCT116 is deficient in wild-type liMIJII. is defective in mismatch repair (MMR), exhibits microsatellite instability, and is tolerant to JV-methylWV'-nitro-JV-nitrosoguanidine (MNNG). Transferring a normal copy of li.MI.III on chromosome 3 into the cell line restores MMR activity, stabilizes microsatellite loci, and increases the sensitivity of the cell to MNNG. ...

The cyclic nucleotides, cyclic adenosine 3':5'-monophosphate (cAMP) and cyclic guanosine 3':5'-monophosphate (cGMP) or their dibutyryl and monobrominated derivatives, may either increase or decrease morphological transformation of Syrian hamster embryo cells exposed to N-methyl-N'-nitro-N'-nitrosoguanidine (MNNG). The effect on transformation is primarily a function of the parent cyclic nucleot...

S(N)1-alkylating agents, such as the mutagenic and cytotoxic drug N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), robustly activate the DNA damage-responsive G(2) checkpoint. Establishment of this checkpoint is dependent on a functional mismatch repair (MMR) system; however, exposure to high doses of MNNG overrides the requirement for MMR to trigger G(2) arrest. In addition, unlike moderate-dose e...

In the current study, we investigated the chemopreventive activity of arabinoxylan rice bran, MGN-3/Biobran, against chemical induction of glandular stomach carcinogenesis in rats. Gastric cancer was induced by carcinogen methylnitronitrosoguanidine (MNNG), and rats received MNNG alone or MNNG plus Biobran (40 mg/kg body weight) for a total of 8 months. Averaged results from 2 separate readings...

1-Methyl-i -nitmosourea (MNU) and 1-methyl-3-n itro-1-ni trosoguanidine (MNNG) are potent carcinogens which al kylate nucleic acids. Little is known about their reactions with nuclear proteins. Protein binding occurs via two mech anisms for each compound: alkylation (both), carbamoyla tion (MNU), or guanidination (MNNG). MNU and MNNG were obtained with 14Clabels to investigate these reactions. ...

1-Methyl-i -nitmosourea (MNU) and 1-methyl-3-n itro-1-ni trosoguanidine (MNNG) are potent carcinogens which al kylate nucleic acids. Little is known about their reactions with nuclear proteins. Protein binding occurs via two mech anisms for each compound: alkylation (both), carbamoyla tion (MNU), or guanidination (MNNG). MNU and MNNG were obtained with 14Clabels to investigate these reactions. ...