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RISS 인기검색어
- 검색키워드
- 저자 : Takamura-Enya, Takeji (검색결과 4 건)
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Yagi, kashi,Fujikawa, Yoshihiro,Sawai, Tomoko,Takamura-Enya, Takeji,Ito-Harashima, Sayoko,Kawanishi, Masanobu Korean Society of ToxicologyKorea Environmental Mu 2017 Toxicological Research Vol.33 No.4
Aryl hydrocarbons such as 3-nitrobenzanthrone (NBA), 4-aminobiphenyl (ABP), acetylaminofluorene (AAF), benzo(a)pyrene (BaP), and 1-nitropyrene (NP) form bulky DNA adducts when absorbed by mammalian cells. These chemicals are metabolically activated to reactive forms in mammalian cells and preferentially get attached covalently to the $N^2$ or C8 positions of guanine or the $N^6$ position of adenine. The proportion of $N^2$ and C8 guanine adducts in DNA differs among chemicals. Although these adducts block DNA replication, cells have a mechanism allowing to continue replication by bypassing these adducts: translesion DNA synthesis (TLS). TLS is performed by translesion DNA polymerases-Pol ${\eta}$, ${\kappa}$, ${\iota}$, and ${\zeta}$ and Rev1-in an error-free or error-prone manner. Regarding the NBA adducts, namely, 2-(2'-deoxyguanosin-$N^2$-yl)-3-aminobenzanthrone (dG-$N^2$-ABA) and N-(2'-deoxyguanosin-8-yl)-3-aminobenzanthrone (dG-C8-ABA), dG-$N^2$-ABA is produced more often than dG-C8-ABA, whereas dG-C8-ABA blocks DNA replication more strongly than dG-$N^2$-ABA. dG-$N^2$-ABA allows for a less error-prone bypass than dG-C8-ABA does. Pol ${\eta}$ and ${\kappa}$ are stronger contributors to TLS over dG-C8-ABA, and Pol ${\kappa}$ bypasses dG-C8-ABA in an error-prone manner. TLS efficiency and error-proneness are affected by the sequences surrounding the adduct, as demonstrated in our previous study on an ABP adduct, N-(2'-deoxyguanosine-8-yl)-4-aminobiphenyl (dG-C8-ABP). Elucidation of the general mechanisms determining efficiency, error-proneness, and the polymerases involved in TLS over various adducts is the next step in the research on TLS. These TLS studies will clarify the mechanisms underlying aryl hydrocarbon mutagenesis and carcinogenesis in more detail.
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Kaneko Hiroaki,Ishiwata Shin-ichi,Takamura-Enya Takeji 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.4
Aquatic organisms frequently exhibit clear genetic structures over their distribution ranges. In a previous study, we showed that the mayfly Ecdyonurus yoshidae Takahashi also showed genetic delimitations in the Japanese archipelago. In this paper, we studied the dispersal and migration of this species using the fine-scale genetic structure and historical demographic dynamics in the Sagami River system using the DNA barcoding region mitochondrial cytochrome c oxidase subunit I gene sequence (COI). We detected two major haplogroups con structed from 44 distinct haplotypes in 226 specimens collected from 24 sampling sites. From the highest altitude of 530 m to the lowest of 7 m, the dominant haplotype was widespread throughout the rivers and the six tributaries and even spread to isolated microhabitats upstream. We did not observe genetic differentiation among the six tributaries and 24 sampling sites. Consequently, we estimated that the population occurring in the entire river system is maintained as a meta-population by suitable small-scale habitats. We found that E. yoshidae might be capable of crossing areas with unsuitable habitats, such as gorges and rapid streams. Furthermore, one haplogroup experienced population expansion—which affected the genetic structure across the Sagami River system—and another haplogroup might have migrated from an adjacent catchment.
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Takashi Yagi,Yoshihiro Fujikawa,Tomoko Sawai,Takeji Takamura-Enya,Sayoko Ito-Harashima,Masanobu Kawanishi 한국독성학회 2017 Toxicological Research Vol.33 No.4
Aryl hydrocarbons such as 3-nitrobenzanthrone (NBA), 4-aminobiphenyl (ABP), acetylaminofluorene (AAF), benzo(a)pyrene (BaP), and 1-nitropyrene (NP) form bulky DNA adducts when absorbed by mammalian cells. These chemicals are metabolically activated to reactive forms in mammalian cells and preferentially get attached covalently to the N² or C8 positions of guanine or the N6 position of adenine. The proportion of N² and C8 guanine adducts in DNA differs among chemicals. Although these adducts block DNA replication, cells have a mechanism allowing to continue replication by bypassing these adducts: translesion DNA synthesis (TLS). TLS is performed by translesion DNA polymerases—Pol η, κ, ι, and ζ and Rev1—in an error-free or error-prone manner. Regarding the NBA adducts, namely, 2-(2"-deoxyguanosin-N²-yl)-3-aminobenzanthrone (dG-N²-ABA) and N-(2"-deoxyguanosin-8-yl)-3-aminobenzanthrone (dG-C8-ABA), dG-N²-ABA is produced more often than dG-C8-ABA, whereas dG-C8-ABA blocks DNA replication more strongly than dG-N²-ABA. dG-N2-ABA allows for a less error-prone bypass than dG-C8-ABA does. Pol η and κ are stronger contributors to TLS over dG-C8-ABA, and Pol κ bypasses dG-C8-ABA in an error-prone manner. TLS efficiency and error-proneness are affected by the sequences surrounding the adduct, as demonstrated in our previous study on an ABP adduct, N-(2"-deoxyguanosine-8-yl)-4-aminobiphenyl (dG-C8-ABP). Elucidation of the general mechanisms determining efficiency, errorproneness, and the polymerases involved in TLS over various adducts is the next step in the research on TLS. These TLS studies will clarify the mechanisms underlying aryl hydrocarbon mutagenesis and carcinogenesis in more detail.
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Kaneko Hiroaki,Ishiwata Shin‐ichi,Bae Yeon Jae,Takamura‐Enya Takeji 한국곤충학회 2021 Entomological Research Vol.51 No.5
Because of their early divergence in insect evolution, unique aquatic larval stage, and low dispersal ability, many mayfly species exhibit genetic structures that accurately reflect geological history and paleoclimatic changes. The present study investigated the genetic characteristics of Ecdyonurus yoshidae Takahashi (Ephemeroptera: Heptageniidae), a mayfly that inhabits a variety of freshwater habitats in Japan. Mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (16S rRNA) gene sequences were generated from 209 mayfly specimens that were collected from 109 sites in Japan. A total of 145 haplotypes were detected, and nine of the lineages exhibited geographical regionality, with one lineage being endemic to Lake Biwa. The haplotype network was “bottleneck type” and included both star-like structures and missing (or unobserved) haplotypes. Together, the haplotype network and FST values indicated that the Fukuejima Island group (Clade I) was genetically distinct from groups on the island of Kyushu, which is separated from Fukuejima Island by the Gotonada Sea. The common ancestor of E. yoshidae lineages in Japan was estimated to have diverged 1.14 mega-annum (Ma) (95% highest posterior density interval, 0.55–1.78 Ma), and more regional genetic diversities were generated during the Middle to Late Pleistocene. Genetically distinct lineages of eastern and western Japan were separated by the Kinki Triangle region in central Japan. The genetic diversity of the habitat generalist E. yoshidae increased during the Middle and Late Pleistocene, when crustal movement and climate change in the Japanese archipelago occurred simultaneously.
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