Biography:

In the past Sakae Arimoto has collaborated on articles with Hikoya Hayatsu and Akira Ishii. One of their most recent publications is Inihibitory effect of the ether extract of human feces on activities of mutagens: Inhibition of oleic and linoleic acids. Which was published in journal Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis.

More information about Sakae Arimoto research including statistics on their citations can be found on their Copernicus Academic profile page.

Sakae Arimoto's Articles: (6)

Inihibitory effect of the ether extract of human feces on activities of mutagens: Inhibition of oleic and linoleic acids

Abstract•An ether extract of normal human faces showed inhibitory effects on the activities of several mutagens in the Ames tests. By addition of the ether extract at an amount equivalent to 0.5 g of a sample of feces, the mutagenicity of 1.5 nmole of 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) on Salmonella typhimurium TA98 was completely inhibited. No killing of the bacteria was detected during this treatment. Other mutagens also subject to the inhibitio were 2-amino-6-dipyridol[1,2-a:3′,2′-d]imidazole (Glu-P-1), 2-amino-9H-pyrido[2,3-b]indole (Glob-P-2), 2-amino-3-methylimidazo[4,5-d]-quinoline (IQ), benzo[a]pyrene and aflatoxin B1. Apart from these mutagens, which require S9 for their activation, the direct mutagen prepared from Trp-P-1 by treatment with S9 was also inhibited by the fecal extract.•The inhibitory principles in the fecal extract were fractionated by thin-layer chromatography on silica gel and were identified as oleic and linoleic acids. Whereas these unsaturated fatty acids showed stron inhibitory activities, saturated fatty acids, 1.e. stearic and palmitic acids, did not exhibit any inhibition.•Although the physiological significance of these effects of oleate and linoleate is yet to be elucidated, this finding has indicated that care must be taken in screening mutagens by the Ames tests to avoid flase negatives resulting from the presence of unsaturated fatty acids in the system.•Modulation of the activity of environmental mutagens has been extensively studies. (See reviews by De Serres, 1978; Nagao et al., 1978.) We have shown that hemin is a potent inhibitor for the activities of mutagens that bear polycyclic structures; those mutagens include Trp-P-1 (the tryptophan pyrolysis product) (Arimoto et al., 1980a), benzo[a]pyrene (Arimoto et al., 1980b) and aflatoxin B1 (Arimoto et al., 1980b). In contrast, cysteine enhances the activity of Trp-P-1 (Negishi and Hayatsu, 1979).•We report here that ether extracts of normal human feces exhibit inhibitory actions on several mutagens in the Ames tests and that, by fractionating the extracts, we identified the inhibitory priciples as oleic and linoleic acids.

Evaluation of the mutagenicity and the tumor-promoting activity of parasite extracts: Schistosoma japonicum and Clonorchis sinensis

AbstractIn relation to the observed association of carcinogenesis with parasitic infections, the mutagenicity of extracts of Schistosoma japonicum and Clonorchis sinensis was examined. In the bacterial mutagenicity tests using the Ames Salmonella typhimurium strains TA98, TA100, TA97 and TA102, and Escherichia coli WP2 and WP2 uvrA pKM101 Schistosoma soluble egg antigen and a homogenate of adult Schistosoma worms showed no positive responses either in the presence or in the absence of S9 mix. Likewise, adult worm extracts of Clonorchis showed no mutagenicity. The Schistosoma soluble egg antigen showed a weak but significant activity for the induction of Epstein-Barr virus expression in viral genome-carrying human lymphoblastoid cells in culture. This phenomenon suggests that the soluble egg antigen possesses tumor-promoting activity.

Inhibitory effect of hemin, chlorophyllin and related pyrrole pigments on the mutagenicity of benzo[a]pyrene and its metabolites

AbstractHemin and chlorophyllin are known to inhibit strongly the mutagenicity of benzo[a]pyrene in the Salmonella assay. To further investigate this phenomenon, a series of these pyrrole pigments including pure samples of Cu- and Fe-chlorins were tested for their potency to inhibit the mutagenicity of benzo[a]pyrene and its metabolites, benzo[a]pyrene-7,8-diol, benzo[a]pyrene4,5-epoxide, and benzo[a]pyrene-7,8-diol-9,10-epoxide. Hemin was the most potent amongthe pigments tested for these inhibitions. Both hemin and Cu-chlorin accelerated efficiently the degradation of benzo[a]pyrene-7,8-diol-9,10-epoxide, and this acceleration seemed to be the predominant mechanism by which these pigments inhibit the overall mutagenicity of benzo[a]pyrene in Salmonella. Based on spectroscopic evidence, we speculate that a complex formation between hemin and benzo[a]pyrene-7,8-diol-9,10-epoxide takes place and that this complexing is the cause of the accelerated degradation.

Adsorption of mutagens to cotton bearing covalently bound trisulfo-copper-phthalocyanine

AbstractA method for separating nonpolar mutagens from their dilute aqueous solutions is described. It utilizes the affinity of the mutagens to a phthalocyanine derivative attached to cotton through a covalent bond. For mutagens having 3 or more fused aromatic rings in their structures, efficient adsorption took place on soaking the cotton in their solutions. The mutagens adsorbed can be recovered by elution with ammoniacal methanol. Mutagenicity in smoker's urine, cooked beef, and river water was detected by use of this method.

Modified metabolism of a carcinogen, 3-amino-1-methy-5H-pyrido[4,3-b]indole (Trp-P-2), by liver S9 from Schistosoma japonicum-infected mice

Abstractschitosoma japonicum infection has been associated with an increased incidence of liver and colorectal cancers in humans. To explore the mechanisms underlying this association, we investigated the carcinogen-metabolizing properties of liver S9 preparations from S. japonicum-infected mice and compared then with those of S9 from uninfected animals. When the carcinogen 3-amino-1-methyl-5H-pyridol[4,3-b]indole (Trp-P-2) was incubated with these S9s and the products were analyzed by high-performance liquid chromatography, we observed that the S9 from infected mice had a lower ability to convert Trp-P-2 into 30-hydroxyamino-1-methyl-5H-pyridol[4,3-b]indole (Trp-2(NHOH)), an activated form of promutagenic Trp-P-2, than the S9 from uninfected mice. We found that both of these S9 preparations have a high ability to reduce Trp-P-2(NHOH) into Trp-P-2; however, the infected-mouse S9 showed a significantly greater reducing power than the control S9. This difference appears to be responsible for the observed lower mutagen-activating potential of the infected mouse S9. These results suggest that hepatic enzyme activities of S. japonicum-infected mice are quantitatively different from those of normal mice.

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