Vol. 23-1 Contents
目 次

Inhibitory effects of herbal teas and herb extracts on the mutagenicity of 1-methyl-1, 2, 3, 4-tetrahydro- β -carboline-
3-carboxylic acid upon treatment with nitrite in the presence of ethanol
   Minoru Higashimoto, Yoshinobu Akada, Masao Sato, Yoshihide Yamada, Tomomi Kuwahara and
   Yoshinari Ohnishi …………………………………………………………………………………………………1

第29 回大会受賞講演
学術賞  JEMS Award 2000
Establishment of regulatory sciences in the field of mutagenesis research
   Toshio Sofuni
変異原研究領域におけるレギュラトリーサイエンスの確立
   祖父尼俊雄…………………………………………………………………………………………………………9

研究奨励賞 JEMS Achievement Award 2000
Recombinational DNA repair and maintenance of genomic integrity mediated by p53
   Masamitsu Honma
がん抑制遺伝子p53 の組換え修復を介した遺伝的安定化機構
   本間正充……………………………………………………………………………………………………………15

Mechanisms for the oxidative stress response and oxidative mutagenesis in Escherichia coli
   Tatsuo Nunoshiba
大腸菌の活性酸素防御応答と突然変異誘発機構に関する研究
   布柴達男……………………………………………………………………………………………………………23
 

第29 回大会シンポジウム
Symposium, 29th JEMS annual meeting, 2000
レスポンダーとノンレスポンダー;遺伝的多型と環境変異原研究
Responders and nonresponders ;Genetic polymorphism and environmental mutagen research
Effects of polymorphism in drug-metabolizing enzymes in the mutagenic activation of chemicals
  Tetsuya Kamataki, Ken-ichi Fujita, Hirotaka Kushida, Yuri Umetsu, Masami Miyamoto, Noritaka Ariyoshi
薬物代謝酵素の遺伝的多型の変異原活性化における意義
   鎌滝哲也,藤田健一,串田浩孝,梅津有理,宮本昌美,有吉範高…………………………………………33

今,私の考える環境変異原研究とは;21 世紀に向けて
My consideration on environmental mutagen research :Perspectives for the 21st century
My consideration on environmental mutagen research :Perspectives for the 21st century
   Yu F. Sasaki and Toshio Sofuni
今,私の考える環境変異原研究とは;21 世紀に向けて
   佐々木 有,祖父尼俊雄……………………………………………………………………………………………39

付録

Committee on Mutagenicity of Chemicals in Food, Consumer Products and the Environment (COM )
Guidance on a Strategy for Testing of Chemicals for Mutagenicity …………………………………………………45
 
 



Vol. 23-1 Summary

Original Article
Inhibitory effects of herbal teas and herb extracts on the mutagenicity of 1-methyl-1, 2, 3, 4-tetrahydro- β -carboline-
3-carboxylic acid upon treatment with nitrite in the presence of ethanol
Minoru Higashimoto, Yoshinobu Akada, Masao Sato, Yoshihide Yamada, Tomomi Kuwahara and Yoshinari Ohnishi
Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan,
Yamada Yakken Co., Ltd., Osaka 577-0948, Japan,
School of Medicine, The University of Tokushima, Tokushima 770 - 8503, Japan
Summary
The mutagenicity of 1-methyl-1, 2, 3, 4-tetrahydro- β -carboline-3-carboxylic acid (MTCCA ), a
major mutagen precursor in soy sauce, upon treatment with nitrite and ethanol was considerably
reduced by the addition of herbal tea or herb extracts in the reaction mixture when it was treated
with 50 mM nitrite at pH 3, 37 ℃for 60 min in the presence of 7.5 %ethanol. Among the herbal teas
tested, Banaba and Tencha teas showed strong mutagenicity-reducing activity, and Kakinoha,
Kakidooshi and Yomogi teas, and Tochu and Senna teas also showed moderate and weak
antimutagenicity, respectively, in the Ames Salmonella mutagenicity test. Abundant amounts of
typical polyphenols such as catechins were detected in the highly antimutagenic herbal teas. The
antimutagenicity and the reducing power of herbal teas were positively correlated. Among the herb
extracts tested, Jiou extract showed strong antimutagenicity and Touki extract was mildly
antimutagenic. Oubaku extract showed strong bactericidal activity because of its high content of
alkaloid berberine. Diluted Oubaku extract showed dose-dependent antimutagenicity. These results
suggest that the mutagenicity of MTCCA upon treatment with nitrite in the presence of ethanol is
decreased by mixed fractions containing polyphenols such as catechins, which have strong
reducing power, and other compounds such as derivatives of catechins, which have little reducing
power.
Keywords :antimutagenicity, herb, nitrosation, soy sauce, ethanol
Abbreviations :MTCCA, 1-methyl-1, 2, 3, 4-tetrahydro- β -carboline-3-carboxylic acid ;EC,
(−)-epicatechin ;ECG,(−)-epicatechin gallate ;EGC,(−)-epigallocatechin ;EGCG,
(−)-epigallocatechin gallate ;FIA, flow-injection analysis ;HPLC, high-performance liquid
chromatography.
received :September, 14, 2000 accepted :February 14, 2000
Environmental Mutagen Society of Japan



学術賞 
JEMS Award 2000
変異原研究領域におけるレギュラトリーサイエンスの確立
祖父尼 俊雄
オリンパス光学工業(株)ライフサイエンステクノロジーリサーチセンター
〒192-8512 東京都八王子市久保山町2-3
Establishment of regulatory sciences in the field of mutagenesis research
Toshio Sofuni
Life Science Technology Research Center, Olympus Optical Co., Ltd.
2-3 Kuboyama-cho, Hachioji-shi, Tokyo 192 - 8512, Japan
Summary
“Regulatory sciences ”are defined as “sciences to regulate results obtained from basic research fields for
practical use in human society ”. Since not all products of basic research will be useful to society, it is
important to be able to select those products which are most likely to be useful Furthermore, while some
products may be profitable, thery may be hazardous to humans if handled in appropriately. Therefore, it is
important to have processes to evaluate the relative merits of accumulated basic research results, even
though such processes may have some limitations. For highly accurate prediction or extrapolation beyond
such results, one majior requirement is an extensive and high quality database that will help generate
“standards (guidelines )for evaluation ”with consensus from the regulatory, academic and industry sides.
However, it is difficult to establish such a database in basic research fields and relatively large collaborative
studies with cooperation of the regulators, academic and industry are essential to establish such database.
The achievements in several intra/international collaborative studies on the mouse micronucleus tests, the
chromosomal aberration and micronucleus tests using cultured mammalian cells, and the mouse lymphoma
tk assays, are introduced to demonstrate their usefulness in the regulatory sciences.
Keywords :regulatory sciences, mutagenesis research, in vitro chromosomal aberration test, mouse
lymphoma tk assay, in vitro micronucleus test
受付:2001 年4 月24 日 受理:2001 年4 月27 日
本稿は日本環境変異原学会第29 回大会において発表された2000 年度学術賞受賞講演である.
This paper is the lecture of the JEMS Award (2000 )presented at the 29th JEMS annual meeting, 2000.
 

研究奨励賞
JEMS Achievement Award 2000
がん抑制遺伝子p53 の組換え修復を介した遺伝的安定化機構
本間 正充
国立医薬品食品衛生研究所変異遺伝部 〒158-8501 東京都世田谷区上用賀1-18-1
Recombinational DNA repair and maintenance of genomic integrity mediated by p53
Masamitsu Honma
National Institute of Health Sciences, Division of Genetics and Mutagenesis
1-81-1 Kamiyoga, Setagaya-ku, Tokyo 158 - 8501, Japan
Summary
Chromosomal double strand breaks (DSB )occurring in mammalian cells can initiate genomic instability
and their misrepairs result in chromosomal deletion, amplification, or translocation, common findings in
human tumors. The tumor suppressor protein p53 is involved in maintaining genomic stability. We
demonstrate here that the deficiency of wild-type p53 protein may allow unrepaired DSB to initiate
chromosomal instability. The human lymphoblastoid cell line TK6-E6 was established by transfection with
HPV16 E6 cDNA into parental TK6 cells via a retroviral vector. Abrogation of p53 function by E6 resulted in
an increase in the spontaneous mutation frequencies at the heterozygous thymidine kinase (tk )locus.
Almost all TK-deficient mutants from TK6-E6 cells exhibited loss of heterozygosity (LOH )with the
hemizygous tk allele. LOH analysis with microsatellite loci spanning the long arm of chromosome 17, which
harbors the tk locus, revealed that LOH extended over half of 17q toward the terminal end. Cytogenetic
analysis of LOH mutants by chromosome painting indicated a mosaic of chromosomal aberrations involving
chromosome 17, in which partial chromosome deletions, amplifications and multiple translocations appeared
heterogeneously in a single mutant. We speculate that spontaneous DSB triggers the breakage-fusion-bridge
cycle leading to such multiple chromosome aberrations. In contrast, no chromosomal alterations
were observed in TK-deficient mutants from TK6-20C cells expressing wild-type p53. In wild-type p53 cells,
spontaneous DSB appear to be promptly repaired through recombination between homologous
chromosomes. These results support a model in which p53 protein contributes to the maintenance of
genomic integrity through recombinational repair.
Keywords :p53, genomic instability, double-strand break (DSB ), recombinational DNA repair, loss of
heterozygosity (LOH )
受付:2001 年4 月25 日 受理:2001 年5 月7 日
日本環境変異原学会
本稿は日本環境変異原学会第29 回大会において発表された2000 年度研究奨励賞受賞講演である.
This paper is the lecture of the JEMS Achievement Award (2000 )presented at the 29th JEMS annual meeting, 2000.
 

大腸菌の活性酸素防御応答と突然変異誘発機構に関する研究
布柴 達男
東北大学大学院生命科学研究科分子生命科学専攻遺伝子システム学講座
〒989-8578 仙台市青葉区荒巻字青葉
Mechanisms for the oxidative stress response and oxidative mutagenesis in Escherichia coli
Tatsuo Nunoshiba
Institute of Biomolecular Science, Graduate School of Life Science, Tohoku University,
Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 989 - 8578, Japan
Summary
Bacterial cells employ transcriptional factors which sense elevated levels of oxidative stress and regulate
expression of antioxidant genes. In E. coli, two redox-responsive transcriptional regulators, SoxR and OxyR,
have been well characterized. The SoxR contains iron-sulfur centers to sense superoxide stress or nitric
oxide. The OxyR contains a thiol-sulfide redox-switch to sense peroxide stress. In this review, I present
discussion about the source of oxidative stress in bacteria, oxidative lesions of cellular bio-molecules, the
antioxidant responses and their regulation mechanisms.
Keywords :OxyR ,SoxR ,disulfide bond ,iron-sulfur cluster ,transcriptional activator
受付:2001 年5 月9 日 受理:2001 年5 月24 日
日本環境変異原学会
本稿は日本環境変異原学会第29 回大会において発表された2000 年度研究奨励賞受賞講演である.
This paper is the lecture of the JEMS Achievement Award (2000 )presented at the 29th JEMS annual meeting, 2000.
 
 



Symposium
薬物代謝酵素の遺伝的多型の変異原活性化における意義
鎌滝 哲也,藤田 健一,串田 浩孝,梅津 有理,宮本 昌美,有吉 範高
北海道大学大学院薬学研究科代謝分析学分野 〒060-0812 札幌市北区北12 条西6 丁目
Effects of polymorphism in drug-metabolizing enzymes in the mutagenic activation of chemicals
Tetsuya Kamataki, Ken-ichi Fujita, Hirotaka Kushida, Yuri Umetsu, Masami Miyamoto, Noritaka Ariyoshi
Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences,
Hokkaido University, N12W6, Kita-ku, Sapporo 060 - 0812, Japan
Summary
The role of human cytochrome P450 (CYP )in the metabolic activation of tobacco-related N-nitrosamines
was examined by Salmonella mutation test using genetically engineered Salmonella typhimurium (S.
typhimurium )YG7108 cells expressing CYP2A6 together with human NADPH-cytochrome P450 reductase.
Seven tobacco-related N-nitrosamins, vis. N-nitrosoanabasine, N-nitrosoanatabine, N-nitrosodiethylamine, 4-
(methylnitrosamino )-1-(3-pyridyl )-1-butanone, N-nitrosonornicotine, N-nitrosopiperidine and N-nitrosopyrrolidine
were used. Interestingly, CYP2A6 was responsible for the mutagenic activation of
essentially all tobacco-related N-nitrosamines examined in the present study.
Genetic polymorphism of the CYP2A6 gene appears to be the major factor in the interindividual variability
of cancer susceptibility. We found the deletion of the whole CYP2A6 gene (CYP2A6*4C )as a type of genetic
polymorphism in Japanese, and developed a gene diagnosis method to detect the varliant. Thus, we
evaluated the relationship between CYP2A6*4C and the susceptibility to lung cancer. The frequency of
CYP2A6*4C was significantly lower in lung cancer patients than in healthy volunteers, suggesting that the
subjects carrying the CYP2A6*4C alleles are resistant to carcinogenesis caused by N-nitrosamines because
of reduced metabolic activation capacity.
Keywords :cytochrome P450, lung cancer, N-nitrosamine, tobacco smoke
受付:2001 年4 月24 日 受理:2001 年4 月26 日
日本環境変異原学会
本稿は日本環境変異原学会第29 回大会シンポジウム I「レスポンダーとノンレスポンダー;遺伝的多型と環境変異原研究」で発表された.
This paper was presented to the symposium I“Responders and nonresponders ;Genetic polymorphism and environmental mutagen
research ”at the 29th JEMS annual meeting, 2000.
 

今,私の考える環境変異原研究とは;21 世紀に向けて
佐々木 有 ,祖父尼 俊雄
1八戸工業高等専門学校 〒039-1192 青森県八戸市田面木上野平16-1
2オリンパス光学工業(株),LRC 〒192-8512 東京都八王子市久保山町2-3
My consideration on environmental mutagen research :Perspectives for the 21st century
Yu F. Sasaki and Toshio Sofuni
Hachinohe National College of Technology, Tamonoki Uwanotai 16-1, Hachinohe, Aomori 039-1192, Japan
LRC, Olympus Optical Co. Ltd., 2-3 Kuboyama-cho, Hachioji-shi, Tokyo 192-8512, Japan
Summary
This is a report of the Symposium entitled “My consideration on environmental mutagen research :
Perspectives for the 21st century ”which was held at the 29th Annual Meeting of the Japanese
Environmental Mutagen Society on November 16, 2000 in Sendai. Six speakers from different institutes
such as University (Professor Hayatsu ), National Institute (Drs Wakabayashi, Hayashi and Nohmi ),
Contact Laboratory (Dr. Tanaka )and Pharmaceutical Laboratory (Dr. Shimada )presented their opinions
on environmental mutagen researches, activites, and especially their perspectives on this research field for
the 21st century. The issues presented by these speakers address essential components for establishment of
a strategy of environmental mutagen research in to the 21st century.
Keywords :environmental mutagen research, perspective, 21st century
受付:2001 年4 月27 日 受理:2001 年5 月7 日
本稿は日本環境変異原学会第29 回大会シンポジウム II「今,私の考える環境変異原研究とは;21 世紀に向けて」で発表された.
This paper was presented to the symposium II“My consideration on environmental mutagen research :Perspectives for the 21st century ”
at the 29th JEMS annual meeting, 2000.