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1.
Dietary inhibitors of mutagenesis and carcinogenesis 总被引:12,自引:0,他引:12
Dietary inhibitors of mutagenesis and carcinogenesis are of particular interest because they may be useful for human cancer prevention. Several mutagenesis inhibitors have been demonstrated to be carcinogenesis inhibitors also, e.g., ellagic acid, palmitoleic acid, and N-acetylcysteine. This means that the search for mutagenesis inhibitors may be useful for discovering anticarcinogenic agents. Many mutagenesis inhibitors have been discovered by the use of short-term assays, particularly the Ames Salmonella test. This simple in vitro system has provided opportunities to elucidate the mechanisms of inhibition. The elucidation of the mechanism may allow us to infer the possible anticarcinogenic activity of the reagent. In this chapter, inhibitors of mutagenesis and carcinogenesis that can arise as components of diet have been reviewed. Most of the inhibitors have been demonstrated to be effective against a specific class of mutagens or carcinogens. Therefore, it may be argued that these inhibitors are antagonistic only to those particular agents. Here again, understanding of the mechanisms of these inhibitions is necessary for the assessment. Dietary inhibitors reviewed in this article include: (1) as inhibitors of mutagenesis: porphyllins, fatty acids, vitamins, polyphenols, and sulfhydryl compounds, (2) as inhibitors of carcinogenesis: vitamins A, E and C, ellagic acid, sulfhydryl compounds, fats, selenium, calcium, and fiber. Further studies in this area of science appear to help establish the recipe of a healthy diet. 相似文献
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3.
Komeda Yoshibumi; Yamashita Hirofumi; Sato Naoki; Tsukaya Hirokazu; Naito Satoshi 《Plant & cell physiology》1991,32(6):737-743
The 5'-upstream region (2.4 kb) of the gene for phytochromeI from Pisum sativum (phyl) was fused to the uidA gene fromEscherichia coli that encodes ß-glucuronidase (GUS).The resulting PHY-GUS fusion was introduced into Petunia hybridaand was used as a reporter of the expression of the phyI genewhich was recognized by GUS activity. The PHY-GUS fusion wasexpressed at a relatively high level when transgenic plantswere grown in the dark, while leaves and stems of light-grownplants showed background activity. Flowers of light-grown plantswere shown to have significant levels of GUS activity but rootsdid not have such activity. When light-grown transgenic plantswere transferred to the dark, they expressed the activity atlevels that corresponded to those of dark-grown plants. Lighttreatment prior to growth in darkness revealed red/far-red reversibilityof recovery of the activity. Thus, the 2.4-kb fragment fromthe 5' region of the phyI gene carries the information necessaryfor the light-repressible autoregulation. (Received March 30, 1991; Accepted May 20, 1991) 相似文献
4.
Adsorption of mutagens to cotton bearing covalently bound trisulfo-copper-phthalocyanine 总被引:2,自引:0,他引:2
H Hayatsu T Oka A Wakata Y Ohara T Hayatsu H Kobayashi S Arimoto 《Mutation research》1983,119(3):233-238
A 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. 相似文献
5.
Hirokazu Kishimoto 《Ichthyological Research》1989,36(3):303-314
Heretofore the genusGnathagnus (Uranoscopidae) has been composed of three species:G. elongatus (Temminck et Schlegel) from northern Australia to Japan,G. innotabilis (Waite) from Australasia, andG. egregius (Jordan et Thompson) from the western Atlantic Ocean. In this paper, a new species and a new subspecies from northwestern Australia are described and a key to the known species and subspecies of the genus is presented. 相似文献
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Souichi Satoh †Tatsuo Kimura †Masahiro Toda †Mutuko Maekawa †Satoshi Ono †Hirokazu Narita Hiroyuki Miyazaki Toshihiko Murayama Yasuyuki Nomura 《Journal of neurochemistry》1997,69(5):2197-2205
Abstract: Nitrogen oxides, such as nitric oxide, have been shown to regulate neuronal functions, including neurotransmitter release. We investigated the effect of S-nitroso-l -cysteine (SNC) on noradrenaline (NA) release in the rat hippocampus in vivo and in vitro. SNC stimulated [3H]NA release from prelabeled hippocampal slices in a dose-dependent manner. SNC stimulated endogenous NA release within 30 min to almost five times the basal level in vivo (microdialysis in freely moving rats). In a Na+-containing Tyrode's buffer, SNC-stimulated [3H]NA release was inhibited 30% by the coaddition of l -leucine. In the Na+-free, choline-containing buffer, SNC-stimulated [3H]NA release, which was similar to that in the Na+-containing buffer, was inhibited markedly by l -leucine, l -alanine, l -methionine, l -phenylalanine, and l -tyrosine. The effects of the other amino acids examined were smaller or very limited. The effect of l -leucine was stronger than that of d -leucine. A specific inhibitor of the L-type amino acid transporter, 2-aminobicyclo[2.2.1]-heptane-2-carboxylate (BCH), inhibited the effects of SNC on [3H]NA release in the Na+-free buffer. Uptake of l -[3H]leucine into the slices in the Na+-free buffer was inhibited by SNC, BCH, and l -phenylalanine, but not by l -lysine. The effect of SNC on cyclic GMP accumulation was not inhibited by l -leucine, although SNC stimulated cyclic GMP accumulation at concentrations up to 25 µM, much less than the concentration that stimulates NA release. These findings suggest that SNC is incorporated into rat hippocampus via the L-type-like amino acid transporter, at least in Na+-free conditions, and that SNC stimulates NA release in vivo and in vitro in a cyclic GMP-independent manner. 相似文献
8.
Yuichi Takeuchi Reiko Fukumoto Hirokazu Kasahara Takeshi Sakaki Mitsutoshi Kitao 《Plant cell reports》1995,14(9):566-570
Cotyledons excised from dark-grown seedlings of cucumber (Cucumis sativus L.) were cultured in vitro under UV radiation at different wavelengths, obtained by passage of light through cut-off filters with different transmittance properties. Growth and the synthesis of chlorophyll (Chl) in cotyledons were inhibited and malondialdehyde was accumulated upon irradiation at wavelengths below 320 nm. Exogenous application of scavengers of free radicals reversed the growth inhibition induced by UV-B. Measurement of the fluorescence of Chl a suggested that electron transfer in photosystems was affected by UV-B irradiation. On the basis of these results, the involvement is postulated of active species of oxygen in damages to thylakoid membranes and the growth inhibition that are induced by UV-B irradiation.Abbreviations Chl
chlorophyll
- Fm
maximal fluorescence (dark)
- Fm
maximal fluorescence (light)
- Fv
variable fluorescence (dark)
- Fv
variable fluorescence (light)
- MDA
malondialdehyde
- O2
Superoxide radical
- PS
photosystem
- qN
non-photochemical quenching of fluorescence
- qP
photochemical quenching of fluorescence
- UV-BBE
biologically effective UV-B radiation
- WL(T = 0.5)
wavelength at which 50% transmittance occurs 相似文献
9.
Takamichi Ichinose Akira K. Suzuki Hirokazu Tsubone Masaru Sagai 《Life sciences》1982,31(18):1963-1972
Strain differences of mice in their susceptibility to nitrogen dioxide (NO2) were examined by measuring the activities of antioxidative protective enzymes, and the amounts of antioxidants and lipid peroxides in lungs. Four strains of mice: ICR, BALB/c, ddy and C57BL/6 were used in this study and their LC50 values after exposure to NO2 for 16 hr were: 38, 49, 51 and 64 ppm, respectively (1).Genetic strain differences were observed in the enzyme activities, the antioxidant contents and lipid peroxide contents among these four different strains. The activities of glutathione peroxidase (GPx), glutathione S-transferase, and superoxide dismutase (SOD), and the contents of non-protein sulfhydryls (NPSH), α-tocopherol (α-Toc) and total lipids in lungs of the four strains were related to their LC50, while TBA reactants in lungs of the four strains were inversely related to their LC50.After exposure to 20 ppm NO2 for 16 hr, the activities of the protective enzymes and the contents of NPSH decreased, while the level of α-Toc increased markedly. The activities of GPx, 6-phosphogluconate dehydrogenase, SOD and disulfide reductase, and the contents of NPSH, α-Toc and total lipids were also related to their LC50. On the other hand, TBA reactants increased higher than those of the control groups and were inversely related to their LC50.These results suggest that the protective enzymes and the antioxidants are important factors as defence mechanism in lungs to NO2 and that the intensity of the protective systems in pigmented strains is generally greater than that in albino strains. 相似文献
10.
When methylmercury was incubated in the presence of selenite and reduced glutathione (GSH), the mercury which was extracted into benzene under acidic condition decreased gradually with the elapse of time. This decrease was due to the cleavage of mercury-carbon bond of methylmercury. The reaction did not proceed when selenite or GSH was singly added to the reaction mixture. L-Cysteine, 2-mercaptoethanol and sodium sulfide in place of GSH also were effective for decomposition of methylmercury in combination with selenite, but oxidized glutathione (GSSG) and L-cystine were not. This suggests that reduction of selenite is needed for the degradation of methylmercury. Thus, the effect of reduced metabolites of selenite produced by GSH was investigated. Glutathione selenotrisulfide (GSSeSG) requierd GSH for the degradation of methylmercury, whereas H2Se possessed a strong activity even in the absence of GSH. This may indicate that H2Se is involved directly in the conversion of methylmercury to inorganic mercury. This phenomenon found in experiments is discussed in relation to the biotransformation of methylmercury. 相似文献