担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Concentrations of fipronil (Fip) and several of its derivatives were detected in samples from four rivers and four estuaries in Japan. LC-MS/MS analysis detected Fip and its derivatives, except for fipronil detrifluoromethylsulfinyl, in almost all samples. The total concentrations of the five compounds were approximately two-fold greater in river water (mean: 21.2, 14.1, and 9.95 ng/L in June, July, and September, respectively) compared to those in estuarine water (mean: 10.3, 8.67, and 6.71 ng/L, respectively). Fipronil, fipronil sulfone (FipS), and fipronil sulfide (FipSf) represented more than 70 % of all compounds. This is the first report to demonstrate the contamination of estuarine waters of Japan by these compounds. We further investigated the potentially toxic effects of Fip, FipS, and FipSf on the exotic mysid, Americamysis bahia (Crustacea: Mysidae). The lowest effective concentrations of Fip-S (10.9 ng/L) and FipSf (19.2 ng/L) on mysid growth and molting was approximately 12.9- and 7.3-fold lower than Fip (140.3 ng/L), suggesting they had higher toxicity. Quantitative reverse transcription polymerase chain reaction analysis revealed that ecdysone receptor and ultraspiracle gene expression were not affected after 96-h of exposure to Fip, Fip-S, and Fip-Sf, suggesting that these genes may not be involved in the molting disruption induced by Fip, Fip-S, and Fip-Sf. Our findings suggest that environmentally relevant concentrations of Fip and its derivatives can disrupt the growth of A. bahia by promoting molting. However, further studies are required to elucidate its molecular mechanism.

DOI： 10.1016/j.scitotenv.2023.164595

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担当区分：筆頭著者  

DOI： 10.1007/978-3-031-27560-9_9

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Equine estrogens (EQs) are steroidal hormones isolated from the urine of pregnant mares and are used in the formulation of human medications. This study initially investigated the embryonic developmental toxicity of equilin (Eq) and equilenin (Eqn) in medaka (Oryzias latipes). Malformations were observed in embryos exposed to nominal concentrations of 1 and 10 mg/L of Eq and Eqn. Delayed hatching was observed at 1 mg/L of Eq. To further investigate the molecular mechanism of developmental toxicity caused by Eq and Eqn, transcriptome and bioinformatics analyses were performed. Among 2016 and 3855 total differentially expressed genes (DEGs), 1117 DEGs overlapped between Eq. (55.4 % of total DEGs) and Eq. (29.0 % of total DEGs). Gene ontology indicated effects in terms related to blood circulation and cell junctions. Pathway analyses using DEGs revealed that both Eq and Eqn treatments at 10 mg/L affected various KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, such as neuroactive ligand-receptor interaction, mitogen-activated protein kinase signaling, retinol metabolism, and cytokine-cytokine receptor interaction. These results suggest that the disruption of these KEGG pathways is involved in the developmental toxicity of EQs in medaka embryos.

DOI： 10.1016/j.cbpc.2023.109547

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

This study aimed to establish zebrafish-based in vivo and in silico assay systems to evaluate the antiandrogenic potential of environmental chemicals. Zebrafish embryos were exposed to 17α-methyltestosterone (TES) alone or coexposed to TES and representative antiandrogens including flutamide, p,p'-DDE, vinclozolin, fenitrothion, and linuron. We assessed the transcript expression of the androgen-responsive gene sulfotransferase family 2, cytosolic sulfotransferase 3 (sult2st3). The expression of sult2st3 was significantly induced by TES in the later stages of embryonic development. However, the TES-induced expression of sult2st3 was inhibited by flutamide in a concentration-dependent manner (IC50: 5.7 μM), suggesting that the androgen receptor (AR) plays a role in sult2st3 induction. Similarly, p,p'-DDE, vinclozolin, and linuron repressed the TES-induced expression of sult2st3 (IC50s: 0.35, 3.9, and 52 μM, respectively). At the highest concentration tested (100 μM), fenitrothion also suppressed sult2st3 expression almost completely. Notably, p,p'-DDE and linuron did not inhibit sult2st3 induction due to higher concentrations of TES; instead, they potentiated TES-induced sult2st3 expression. Fenitrothion and linuron, which had relatively low antiandrogenic potentials in terms of sult2st3 inhibition, induced broader toxicities in zebrafish embryos; thus, the relationship between developmental toxicities and antiandrogenic potency was unclear. Additionally, an in silico docking simulation showed that all five chemicals interact with the zebrafish AR at relatively low interaction energies and with Arg702 as a key amino acid in ligand binding. Our findings suggest that a combination of zebrafish-based in vivo and in silico assessments represents a promising tool to assess the antiandrogenic potentials of environmental chemicals.

DOI： 10.1016/j.cbpc.2022.109513

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s12562-022-01657-3

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その他リンク： https://link.springer.com/article/10.1007/s12562-022-01657-3/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.scitotenv.2021.150631

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.rsma.2021.101957

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

Coral reefs face multiple threats, including climate change, agricultural runoff, shipping activities, coastal development, and chemical pollutants. Irgarol 1051, a PSII herbicide, has been used as an antifouling booster since the previously used antibiofouling agent tributyltin (TBT) was banned worldwide. Although the mechanisms through which elevated temperatures cause coral bleaching have been reported, it remains unclear how PSII herbicides cause bleaching. Thus, in this study, we investigated the transcriptomes of Acropora tenuis and its symbiotic dinoflagellates by RNA-sequencing (RNA-Seq) to elucidate the molecular mechanisms underlying Irgarol-induced bleaching. Coral exposure to 10 μg/L Irgarol for 7 d affected coral body colour, specifically by an increase in their red, green, and blue (RGB) values; however, no such effect was observed in corals exposed to 1 μg/L Irgarol. RNA-Seq revealed the differentially expressed genes (DEGs) in corals and symbiotic dinoflagellates following Irgarol exposure. Coral DEGs encoded green fluorescent protein, blue-light-sensing photoreceptor (cryptochrome), chromoprotein, caspase 8, and nuclear receptors; DEGs in symbiotic dinoflagellates encoded light-harvesting proteins, photosystem II proteins, and heat shock proteins (i.e. HSP70 and HSP90), and ubiquitin. Bioinformatic analyses revealed that both Irgarol treatments disrupted various gene ontology terms, pathways, and protein interaction networks; these are different in corals (e.g. oxidative phosphorylation, metabolic pathway, transforming growth factor-β signalling pathway, adherens junction, and apoptosis) and symbiotic dinoflagellates (e.g. protein processing in endoplasmic reticulum, carbon fixation in photosynthetic organisms, metabolic pathway, and photosynthesis). Our data suggest that Irgarol disrupts the expression of various coral genes, thereby affecting various gene ontology terms, pathways, and protein interaction networks. Our study provides new insights into the potential molecular mechanisms underlying the bleaching effect of PSII herbicides, such as Irgarol, on corals and symbiotic dinoflagellates.

DOI： 10.1016/j.scitotenv.2021.146542

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Equine estrogens (EEs) are widely used in hormone replacement therapy pharmaceuticals for postmenopausal women. Previous studies have shown that EEs occur in the aquatic environment; however, the potential estrogenicity and risk of EEs in aquatic organisms, including fish, have yet to be studied in detail. Therefore, we evaluated the estrogenic potential of major EEs, namely equilin (Eq), 17α-dihydroequilin (17α-Eq), 17β-dihydroequilin (17β-Eq), equilenin (Eqn), 17α-dihydroequilenin (17α-Eqn), and 17β-dihydroequilenin (17β-Eqn), on medaka (Oryzias latipes) using in vivo and in silico assays. Quantitative real-time RT-PCR analyses revealed that expression levels of choriogenin L (ChgL) and choriogenin H (ChgH) in medaka embryos responded to various types and concentrations of EEs in a concentration-dependent manner, whereas transcription levels of vitellogenin 1 were not significantly affected by any of the EEs in the concentration range tested. The order of the in vivo estrogenic potencies of EEs was as follows: 17β-Eq > Eq > 17β-Eqn > Eqn > 17α-Eqn > 17α-Eq. Additionally, the 50% effective concentrations (EC ) of 17β-Eq was lower than that of 17β-estradiol. We also investigated the interaction potential of EEs with medaka estrogen receptor (ER) subtypes in silico using a three-dimensional model of the ligand-binding domain (LBD) for each ER and docking simulations. All six EEs were found to interact with the LBDs of ERα, ERβ1, and ERβ2. The order of the in silico interaction potentials of EEs with each ER LBD was as follows: 17β-Eq > 17α-Eq > Eq > 17β-Eqn > 17α-Eqn > Eqn. Furthermore, we identified the key amino acids that interact with EEs in each ER LBD; our findings suggest that amino acids and/or their hydrogen bonding may be responsible for the ligand-specific interactions with each ER. This study is the first to comprehensively analyze the estrogenic potential of EEs in medaka both in vivo and in silico. 50

DOI： 10.1016/j.scitotenv.2020.144379

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Increased seawater temperature has resulted in mass coral bleaching events globally. Acropora tenuis, the dominant hermatypic coral species in southern Japan, was exposed to four temperature treatments [28 °C, 30 °C, 32 °C, and >32 (=33.3 °C)] for 7 d. The coral colour was converted to R (red), G (green), and B (blue) values, each ranging from 0 (darkest) to 255 (brightest). RGB values exposed to 28 °C and 30 °C decreased slightly, whereas those exposed to 32 °C increased significantly after day 3–6, and those exposed to 33.3 °C changed to white within 2 d. Quantitative RT-PCR analysis revealed no significant changes in heat shock proteins in Acropora and symbiotic dinoflagellates at 28 °C and 30 °C after a 7 d exposure. Our findings revealed that 30 °C, higher than the mean temperature of the warmest month in southern Japan, was an inhabitable temperature for A. tenuis.

DOI： 10.1016/j.marpolbul.2020.111812

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Juvenile hormone (JH) is an important endocrine factor regulating many biological activities in arthropods. In daphnids, methoprene-tolerant (Met) belongs to a basic helix-loop-helix/Per-Arnt-Sim (bHLH/PAS) family protein which has recently been confirmed as a JH receptor and can bind and be activated by JHs and JH agonists. Although the activation of the JH signaling pathway causes many physiological effects, the molecular basis for the structural feature and ligand binding properties of Daphnia Met are not fully understood. To study the ligand preference in terms of structural features of Daphnia Met, we built in silico homology models of the PAS-B domain of Daphnia Mets from cladoceran crustaceans, Daphnia pulex and D. magna. Structural comparison of two Daphnia Met PAS-B domain models revealed that the volume in the main cavity of D. magna Met was larger than that of D. pulex Met. Compared with insect Met, Daphnia Met had a less hydrophobic cavity due to polar residues in the core-binding site. Molecular docking simulations of JH and its analogs with Daphnia Met indicated that the interaction energies were correlated with each of the experimental values of in vivo JH activities based on male induction and in vitro Met-mediated transactivation potencies. Furthermore, in silico site-directed mutagenesis supported experimental findings that Thr292 in D. pulex Met and Thr296 in D. magna Met substitution to valine contribute to JH selectivity and differential species response. This study demonstrates that in silico simulations of Daphnia Met and its ligands may be a tool for predicting the ligand profile and cross species sensitivity.

DOI： 10.1021/acs.chemrestox.0c00179

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Herein, we quantified the concentrations of cadmium（Cd）and arsenic（As）in 63 milled rice （Oryza sativa L.）cultivated in Japan, Vietnam, and Indonesia. We estimated the daily intake of Cd and As by adults and children consuming this rice by inductively coupled plasma-mass spectrometer（ICP-MS）. Cd and As were detected in all milled rice samples. No significant differences were observed in Cd concentrations between Japanese（50th percentile concentration: 0.036 mg/ kg）, Vietnamese（0.035 mg/kg）, and Indonesian rice（0.022 mg/kg）. However, As concentrations in Vietnamese rice（50th percentile concentration: 0.142 mg/kg）were significantly higher than those in Japanese（0.101 mg/kg, p＜0.001）and Indonesian rice（0.038 mg/kg, p＜0.0001）. Target hazard quotients（THQs）were then calculated to evaluate the non-carcinogenic health risk from ingestion of individual heavy metals（Cd and As）by rice consumption. Results revealed that THQs of individual heavy metals for Japanese, Vietnamese, and Indonesian adults and children consuming this rice were all less than one, suggesting that no health risk is associated with the intake of a single heavy metal via rice consumption.

DOI： 10.3358/SHOKUEISHI.61.192

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掲載種別：研究論文（学術雑誌）  

We investigated coral bleaching by monitoring colour changes and measuring the delayed fluorescence (DF) of symbiotic dinoflagellates in the hermatypic coral Acropora tenuis, exposed to 1.0 μg/L Irgarol 1051 (photosystem II herbicide) for 14 d. The Irgarol concentration corresponded to those from international port regions of the world. The coral colour and DFs under the control treatment were stable throughout the experiment, whereas under the Irgarol treatment the corals showed gradual bleaching. The Irgarol treatment caused a rapid decrease in the slow decay DF component (10.1–60.0 s), while the fast decay DF component (0.1–10.0 s) decreased significantly after 6 d. The significant correlation between the latter values and the coral colour indicates that if the electron accumulation function of quinones Q and Q is compromised, corals will bleach. The present study will contribute to the understanding of the mechanism involved in bleaching of coral exposed to herbicides. A B

DOI： 10.1016/j.marpolbul.2020.111008

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

This study assessed the transcription levels of estrogen-responsive genes, such as vitellogenins (Vtg1 and Vtg2), choriogenins (ChgL, ChgH, and ChgHm), cytochrome P450 aromatase (CYP19a1b), and ER subtypes (ERα, ERβ1, and ERβ2), in 7 days-post-fertilization (dpf) embryos and 9 and 12 dpf larvae of medaka (Oryzias latipes) exposed to estrogenic endocrine-disrupting chemicals (EDCs). The <5 h-post-fertilization embryos were exposed to EDCs such as 17β-estradiol (E2), p-n-nonylphenol (NP), and bisphenol A (BPA). In E2 (0.10–222 nM)-treated 7 dpf embryos and 9 or 12 dpf larvae, ChgL, ChgH, and ChgHm expression was up-regulated in a concentration-dependent manner. By contrast, interestingly, Vtg1 and Vtg2 expression was not induced in E2-treated 7 dpf embryos but was significantly induced in 9 and 12 dpf larvae, suggesting a developmental-stage-specific regulatory mechanism underlying Vtg expression. The maximum concentrations of NP (0.09–1.5 μM) and BPA (1.8–30 μM) up-regulated Chg expression in 9 or 12 dpf larvae, and the relative estrogenic potencies (REPs) of E2, NP, and BPA were 1, 2.1 × 10 , and 1.0 × 10 , respectively. Chg messenger RNA (mRNA) in medaka embryos and larvae can be used as a sensitive biomarker for screening potential estrogenic EDCs. Our assay system using embryos and larvae can be used as an in vivo alternative model because independent feeding stages (e.g., embryonic and early larval stages) are suitable alternatives. −4 −5

DOI： 10.1016/j.ecoenv.2020.110324

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掲載種別：研究論文（学術雑誌）  

© 2019 Elsevier Ltd Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BaP), are widely distributed in air, water, and sediments; however, limited data are available regarding their potential adverse effects on the early life stages of fish. In this study, we evaluated the embryonic teratogenicity and developmental toxicity of BaP in Japanese medaka (Oryzias latipes) using a nanosecond pulsed electric field (nsPEF) technique and predicted their molecular mechanisms via transcriptome analysis. The gas chromatography/mass spectrometry analyses revealed that the BaP was efficiently incorporated into the embryos by nsPEF treatment. The embryos incorporating BaP presented typical teratogenic and developmental effects, such as cardiovascular abnormalities, developmental abnormalities, and curvature of backbone. DNA microarray analysis revealed several unique upregulated genes, such as those involved in cardiovascular diseases, various cellular processes, and neural development. Furthermore, the gene set enrichment and network analyses found several genes and hub proteins involved in the developmental effects of BaP on the embryos. These findings suggest a potential mechanism of teratogenicity and developmental toxicity caused by exposure to BaP. The nsPEF and transcriptome analyses in combination can be effective for evaluating the potential effects of chemical substances on medaka embryos.

DOI： 10.1016/j.chemosphere.2019.125243

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掲載種別：研究論文（学術雑誌）  

© 2019 Elsevier Ltd The effects of ecologically relevant concentrations of Irgarol 1051, a representative PSII herbicide, on hermatypic corals were studied in the laboratory. The colour and chlorophyll fluorescence of Acropora tenuis were examined following exposure to around ambient concentrations of Irgarol 1051 (20 ng/L and 200 ng/L) for 7 days. While the colour of corals was stable throughout the experiment at both concentrations, the maximum effective quantum yield (ΔF/Fm′) of symbiotic dinoflagellates decreased with increasing Irgarol 1051 concentration (day 7: 8%, 20 ng/L; 37%, 200 ng/L). The expression of heat shock protein (HSP) 70 and 90 in symbiotic dinoflagellates was upregulated after 7 days exposure to both Irgarol concentrations, whereas HSP90 in coral was not upregulated. The findings of the present study suggest that the threshold of chlorophyll fluorescence and HSP expression in symbiotic dinoflagellates is lower than 20 ng/L, which is around ecologically relevant concentrations in tropical to subtropical waters.

DOI： 10.1016/j.marpolbul.2019.110734

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記述言語：英語   出版者・発行元：(一社)日本毒性学会  

ナノ秒パルス電場(nsPEF)技法とバイオインフォマティクス解析により、リチウム(Li)が、メダカ(Oryzias latipes)の胚発生毒性や催奇形性を及ぼす影響について基礎的検討を行い、その分子機序を明らかにした。その結果、1mg/LのLiCl処理により、胚発達遅滞、眼奇形、心肥大、血栓など重篤な奇形を及ぼす影響が認められた。また、nsPEFとLiCl処理した受精2日後胚のRNA-sq分析を行い、組織形成および器官形成関連の2483遺伝子における上方/下方調節遺伝子を同定した結果では、遺伝子オントロジーによるエンリッチ分析により、LiCl処理胚で、ヌクレオチド結合、ATP結合、RNA結合や核酸結合等の分子機能および細胞成分が有意にエンリッチされることが確認された。さらに、KEGGの遺伝子セットエンリッチ分析により、LiClのスプライセオソーム、細胞周期、セレン化合物代謝、TGF-βシグナリングおよびRNA分解への影響についても観察され、GSK3B、BAXおよびMAP3K8遺伝子の上方調節も認められた。

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

© 2019 American Chemical Society. In this study, we assessed the binding affinities of perfluoroalkyl substances (PFASs), including perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs), to the ligand-binding domains (LBDs) of Baikal seal (Pusa sibirica; bs) and human (h) peroxisome proliferator-activated receptor alpha (PPARα). An in vitro competitive binding assay showed that six PFCAs and two PFSAs could bind to recombinant bs and hPPARα LBD proteins in a dose-dependent manner. The relative binding affinities (RBAs) of PFASs to bsPPARα were as follows: PFOS > PFDA > PFNA > PFUnDA > PFOA > PFHxS > PFHpA > PFHxA. The RBAs to bsPPARα showed a significant positive correlation with those to hPPARα. In silico PPARα homology modeling predicted that there were two ligand-binding pockets (LBPs) in the bsPPARα and hPPARα LBDs. Structure-activity relationship analyses suggested that the binding potencies of PFASs to PPARα might depend on LBP binding cavity volume, hydrogen bond interactions, the number of perfluorinated carbons, and the hydrophobicity of PFASs. Interspecies comparison of the in vitro binding affinities revealed that bsPPARα had higher preference for PFASs with long carbon chains than hPPARα. The in silico docking simulations suggested that the first LBP of bsPPARα had higher affinities than that of hPPARα however, the second LBP of bsPPARα had lower affinities than that of hPPARα. To our knowledge, this is the first evidence showing interspecies differences in the binding of PFASs to PPARαs and their structure-activity relationships.

DOI： 10.1021/acs.est.8b07273

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記述言語：英語   出版者・発行元：日本食品化学学会  

In this study, we determined the concentration of seven neonicotinoid insecticides and 13 of their metabolites in 46 bottled greenteabeverages, and estimated the daily intake of neonicotinoids in adults and children from these drinks. Liquid chromatographycoupled with electrospray ionization tandem mass spectrometry (LC–ESI/MS/MS) analysis revealed that six neonicotinoidsand two metabolites were detected in bottled green-tea beverages, and the 50th percentile concentration indicated dinotefuran > thiacloprid > clothianidin > imidacloprid > thiamethoxam > acetamiprid > N-desmethyl-acetamiprid > thiacloprid-amide. Theconcentration and composition profile of neonicotinoids in bottled green-tea beverages were different between brands; however,no significant differences were observed among manufacturing sites. The concentration of acetamiprid in bottled green-teabeverages was significantly correlated with that of N-desmethyl-acetamiprid. A significant relationship between concentrations ofthiamethoxam and clothianidin in bottled green-tea beverages was also observed, suggesting those neonicotinoids are metabolizedduring the tea leaves cultivation period. The daily intake for neonicotinoids in both adults and children from consumption ofbottled green-tea beverages was < 2.1% when compared with the acceptable daily intake (ADI) of neonicotinoids.

DOI： 10.18891/jjfcs.26.1_17

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

© 2018 American Chemical Society. We investigated the Baikal seal (Pusa sibirica) peroxisome proliferator-activated receptor α (bsPPARα) transactivation potencies of polybrominated diphenyl ethers (PBDEs) using an in vitro bsPPARα reporter gene assay. BDE47, BDE99, and BDE153 induced bsPPARα-mediated transcriptional activities in a dose-dependent manner. To compare bsPPARα transactivation potencies of PBDEs, perfluorooctanoic acid (PFOA)-based relative potencies (REPs), a ratio of 50% effective concentration of PFOA to the test chemical, were determined. The order of REPs of PBDEs was BDE153 (13) > BDE99 (8.1) > BDE47 (6.6) > PFOA (1.0) > BDE100, BDE154, and BDE183 (not activated). PBDEs with two bromine atoms at the ortho position showed higher bsPPARα transactivation potencies than those with three bromine atoms. Comparison of the lowest-observed-effect concentration in bsPPARα reporter gene assays revealed that BDE99 was 7-fold more potent than CB99, a polychlorinated biphenyl congener with the same IUPAC number, indicating that brominated congeners could more efficiently activate bsPPARα than chlorinated congeners. The REPs of PBDEs for bsPPARα transactivation were approximately 7- to 13-fold higher than those of perfluorochemicals (PFCs), suggesting that the effects of PBDEs on the bsPPARα signaling pathway may be superior to those of PFCs. This study provides the first evidence that PBDE congeners activate PPARα in vitro.

DOI： 10.1021/acs.est.8b02501

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

© 2018 In this study, we determined the concentration of equine estrogens, such as equilin (Eq) and equilenin (Eqn), in the river water collected from nine research stations in Hokkaido, Japan. The LC–MS/MS analysis revealed that Eq concentrations were 2.7 ± 6.7, 0.22 ± 0.12, and 1.2 ± 0.64 ng/L in Sep 2015, Feb 2016, and Jul 2016, respectively. Eqn had concentration levels similar to those of Eq. Comparison of the concentrations at nine research stations showed that seasonal variation was observed in the detected Eq and Eqn concentration levels. This study was the first to show the occurrences and seasonal variation of Eq and Eqn in the river water of Japan. We further investigated the reproductive and transgenerational effects of Eq in Japanese medaka (Oryzias latipes) exposed to 10, 100, and 1000 ng/L for 21 days and assessed the transcriptional profiles of the estrogen-responsive genes in the livers of both sexes. The reproduction assay demonstrated that 1000 ng/L of Eq adversely affected the reproduction (i.e. fecundity) in the F0 generation and that the hatching of F1 generation fertilized eggs was reduced in the 100 and 1000 ng/L treatment groups. Our qRT-PCR assay revealed that the mRNA expression levels of hepatic vitellogenin 1 and 2, choriogenin L and H, and estrogen receptor α were significantly up-regulated in males exposed to 100 and/or 1000 ng/L of Eq. In contrast, the transcriptional levels of several genes, such as pregnane X receptor and cytochrome P450 3A, were down-regulated in the livers of males after the 21-d exposure. These results suggest that Eq has endocrine-disrupting potential such as reproductive and transgenerational effects by the modulation of hepatic estrogen-responsive genes expression on medaka. Occurrence, seasonal variation and endocrine-disrupting potentials of equine estrogens.

DOI： 10.1016/j.envpol.2018.04.029

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

© 2018 Elsevier Ltd To elucidate the effects of the herbicide Irgarol 1051 on the gene expression of heat shock protein 90 (HSP90) in hard corals, we isolated a full-length cDNA encoding HSP90 from Acropora tenuis, which has a deduced open reading frame of 732-amino acid residues with a predicted molecular mass of 84.5 kDa. The amino acid sequence of A. tenuis HSP90 showed a high degree of similarity with the hermatypic-coral HSP90 families. After a 7-d exposure to 1 or 10 μg/L of Irgarol, the body colours of corals in the 10 μg/L treatment group were significantly whiter (bleached), whereas no such effects were observed in the corals in the 1 μg/L treatment group. However, the expression level of coral HSP90 was significantly downregulated after exposure to both 1 and 10 μg/L Irgarol. These results suggest that A. tenuis HSP90 may be a useful molecular biomarker to predict bleaching caused by herbicides.

DOI： 10.1016/j.marpolbul.2018.06.014

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掲載種別：研究論文（学術雑誌）  

© 2018 Elsevier Ltd The colours of the hermatypic corals Porites sp. and Acropora cytherea at Sesoko Island, Okinawa, Japan, were photographed continuously, from 19 July to 6 September 2016, by an underwater camera equipped with a lens wiper. The average seawater temperature during the study period was 29.9 °C. The daily average seawater temperature (DAST) was >30.0 °C until 23 August 2016, and a maximum value of 31.2 °C was recorded on 2 August 2016. Red, green, and blue (RGB) values of these corals were analysed based on photographs taken at 14:00. The RGB values of Porites sp. were stable throughout the observation period, while those of A. cytherea gradually increased (i.e. moved toward the “white” end of the spectrum) until the beginning of September. The present study demonstrated the usefulness of RGB analysis of photographs taken by an underwater camera equipped with a lens wiper for monitoring coral beaching.

DOI： 10.1016/j.marpolbul.2018.04.020

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

Copyright © 2017 John Wiley & Sons, Ltd. Herein, we propose using a nanosecond pulsed electric field (nsPEF) technique to assess teratogenicity and embryonic developmental toxicity of estradiol-17β (E 2 ) and predict the molecular mechanisms of teratogenicity and embryonic developmental defects caused by E 2 on medaka (Oryzias latipes). The 5 hour post-fertilization embryos were exposed to co-treatment with 10 μm E 2 and nsPEF for 2 hours and then continuously cultured under non-E 2 and nsPEF conditions until hatching. Results documented that the time to hatching of embryos was significantly delayed in comparison to the control group and that typical abnormal embryo development, such as the delay of blood vessel formation, was observed. For DNA microarray analysis, 6 day post-fertilization embryos that had been continuously cultured under the non-E 2 and nsPEF condition after 2 hour co-treatments were used. DNA microarray analysis identified 542 upregulated genes and one downregulated gene in the 6 day post-fertilization embryos. Furthermore, bioinformatic analyses using differentially expressed genes revealed that E 2 exposure affected various gene ontology terms, such as response to hormone stimulus. The network analysis also documented that the estrogen receptor α in the mitogen-activated protein kinase signaling pathway may be involved in regulating several transcription factors, such as FOX, AKT1 and epidermal growth factor receptor. These results suggest that our nsPEF technique is a powerful tool for assessing teratogenicity and embryonic developmental toxicity of E 2 and predict their molecular mechanisms in medaka embryos.

DOI： 10.1002/jat.3579

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記述言語：日本語   出版者・発行元：日本環境毒性学会  

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掲載種別：研究論文（学術雑誌）  

© 2017 Elsevier Ltd Colour change in Acropora tenuis, a representative species of Indo-Pacific hard coral, in response to low concentrations of Irgarol 1051 was examined in the laboratory. Branches of A. tenuis were exposed to 0, 1, and 10 μg Irgarol 1051/L for 14 days, and photographed daily using digital camera. These Irgarol 1051 concentrations were similar to those recorded at a number of sea ports. Red, green and blue (RGB) coral colour values were quantified from the photographs, with black represented by R = G = B = 0 and white as R = G = B = 255. Exposure to Irgarol 1051 caused RGB values to increase, moving towards the ‘white’ end of the spectrum as Irgarol 1051 concentration increased. These results suggest that the ambient levels of Irgarol 1051 recorded from port environments could be implicated in coral bleaching, if concentrations over nearby reef ecosystems are similar.

DOI： 10.1016/j.marpolbul.2017.05.027

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担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）  

Copyright © 2016 John Wiley & Sons, Ltd. In the present study, we investigated transcriptional profiles of estrogen-responsive genes, such as vitellogenins (Vtg1 and Vtg2), choriogenins (ChgL and ChgH) and estrogen receptor subtypes (ERα, ERβ1, and ERβ2), in the liver of male medaka fish (Oryzias latipes) that were exposed to six equine estrogens (1–300 ng l−1) for 3 days. Our quantitative reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that the expression levels of hepatic Vtg, Chg and ERα genes in male medaka responded to various types and concentrations of equine estrogens. The estrogenic potentials of the tested chemicals were in the order of equilin > 17β-estradiol > equilenin > 17β-dihydroequilin > 17β-dihydroequilenin > 17α-dihydroequilin > 17α-dihydroequilenin, showing the higher estrogenic potential of equilin than that of 17β-estradiol. Our results also showed that the estrogenicities of 17β-dihydroequilin and 17β-dihydroequilenin were more potent than that of 17α-dihydroequilin and 17α-dihydroequilenin. Furthermore, in gene expression analyses of hepatic ER subtypes, observations were made to note that 17β-estradiol and equilin induced ERα transcription in male medaka, and the ERα transcription level had significantly positive correlations with the expression of Vtg and Chg genes. In contrast, in the same 17β-estradiol and equilin treatment groups, it was shown that the transcription levels of hepatic ERβ1 and/or ERβ2 had significantly negative correlations with the expression of Vtg and Chg genes. These results suggested some potential involvement of the ER subtypes in the regulation of Vtg and Chg gene expressions in the liver. This is the first report describing the comprehensive analyses of in vivo estrogenicity of the equine estrogens in male medaka. Copyright © 2016 John Wiley & Sons, Ltd.

DOI： 10.1002/jat.3292

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掲載種別：研究論文（学術雑誌）  

© 2016 Elsevier Inc. Nonylphenol (NP) has been classified as an endocrine-disrupting chemical. In this study, we conducted mysid DNA microarray analysis with which has 2240 oligo DNA probes to observe differential gene expressions in mysid crustacean (Americamysis bahia) exposed to 1, 3, 10 and 30 μg/l of NP for 14 days. As a result, we found 31, 27, 39 and 68 genes were differentially expressed in the respective concentrations. Among these genes, the expressions of five particular genes were regulated in a similar manner at all concentrations of the NP exposure. So, we focused on one gene encoding cuticle protein, and another encoding cuticular protein analogous to peritrophins 1-H precursor. These genes were down-regulated by NP exposure in a dose-dependent manner, and it suggested that they were related in a reduction of the number of molting in mysids. Thus, they might become useful molecular biomarker candidates to evaluate molting inhibition in mysids.

DOI： 10.1016/j.ecoenv.2016.07.037

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掲載種別：研究論文（学術雑誌）  

© The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. Steroid hormone receptor family provides an example of evolution of diverse transcription factors through wholegenome duplication (WGD). However, little is known about how their functions have been evolved after the duplication. Teleosts present a good model to investigate an accurate evolutionary history of protein function after WGD, because a teleost-specific WGD (TSGD) resulted in a variety of duplicated genes in modern fishes. This study focused on the evolution of androgen receptor (AR) gene, as two distinct paralogs, ARa and ARb, have evolved in teleost lineage after TSGD. ARa showed a unique intracellular localization with a higher transactivation response than that of ARb. Using site-directed mutagenesis and computational prediction of protein-ligand interactions, we identified two key substitutions generating a new functionality of euteleost ARa. The substitution in the hinge region contributes to the unique intracellular localization of ARa. The substitution on helices 10/11 in the ligand-binding domain possibly modulates hydrogen bonds that stabilize the receptor-ligand complex leading to the higher transactivation response of ARa. These substitutions were conserved in Acanthomorpha (spiny-rayed fish) ARas, but not in an earlier branching lineage among teleosts, Japanese eel. Insertion of these substitutions into ARs from Japanese eel recapitulates the evolutionary novelty of euteleost ARa. These findings together indicate that the substitutions generating a new functionality of teleost ARa were fixed in teleost genome after the divergence of the Elopomorpha lineage. Our findings provide a molecular explanation for an adaptation process leading to generation of the hyperactive AR subtype after TSGD.

DOI： 10.1093/molbev/msv218

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

© 2015 . Various studies have demonstrated the estrogenic effect of bisphenol A (BPA), a member of bisphenol analogs (BPs), in in vitro and in vivo assays. However, limited data are available on the estrogenic potentials and risks of other BPs in aquatic organisms. In addition, the estrogenic effect of chemicals is known to have species-specific responses in teleost fish. The objective of this study was to evaluate the potential estrogenic effects of BPs on the medaka (Oryzias latipes) and common carp (Cyprinus carpio) using in vivo and in silico assays. Our quantitative real-time PCR analyses revealed that the expression levels of several hepatic estrogen-responsive biomarker genes in male medaka responded to various types and concentrations of BPs in a dose-response manner. The order of in vivo estrogenic potencies of BPs was as follows: BPC⋘BPAF>BPB>BPA⋙BPP. To further investigate the interaction potential of BPs with medaka estrogen receptor α (ERα) in silico, a three-dimensional model of the ERα ligand-binding domain (LBD) was built and docking simulations were performed. The docking simulation analysis revealed that BPC interaction potential for medaka ERα LBD was the most potent, followed by BPAF and BPA. Comparing this with carp ERα LBD revealed that the interaction potentials of these BPs to medaka ERα LBD were more stable than to carp ERα LBD. Furthermore, we identified key amino acid residues in medaka ERα LBD that interacted with BPC (Glu356, Arg397, and Cys533), BPAF (Thr350 and Glu356), and BPA (Glu356 and Met424), and found some differences in these key amino acid residues between medaka and carp ERα LBDs. These results of in vivo and in silico analyses showed potential estrogenic effects of BPs in teleost fish, and they also indicated that the differences in interaction potentials and key amino acid residues between medaka and carp ERα LBDs may be due to the differences between the species and estrogenic potencies of the selected BPs.

DOI： 10.1016/j.ecoenv.2015.06.014

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掲載種別：研究論文（学術雑誌）  

© 2015 John Wiley & Sons, Ltd. Although several previous studies have demonstrated the presence of equine estrogens in the aquatic environment, limited data are currently available on the endocrine-disrupting potentials in fish and the risks they pose to aquatic organisms. To investigate the interactions of major equine estrogens equilin (Eq) and equilenin (Eqn), as well as their metabolites 17α-dihydroequilin, 17β-dihydroequilin, 17α-dihydroequilenin and 17β-dihydroequilenin, with the estrogen receptor α (ERα) of medaka (Oryzias latipes), a three-dimensional model of the ligand-binding domain (LBD) of ERα was built in silico, and docking simulations were performed. The docking simulation analysis indicated that the interaction of 17β-dihydroequilenin with the ERα LBD is the most potent, followed by those of 17α-dihydroequilin and 17β-dihydroequilin, whereas those of Eq and Eqn were least potent. We further analyzed gene expression profiles in the livers of male medaka exposed to Eq and Eqn. A DNA microarray representing 6000 genes revealed that 24-h exposure to Eq and Eqn (100ng/L) upregulated the expression of 6 and 34 genes in the livers of males, respectively. Genes upregulated by Eq included the estrogenic biomarker genes vitellogenins and choriogenins, suggesting the estrogenic potential of Eq. In contrast, Eqn exposure upregulated several cancer-related genes, such as mediator complex subunit 16 and RAS oncogene family members, suggesting a carcinogenic potential for Eqn. These results suggest that equine estrogens may have not only endocrine-disrupting potentials via the ERα signaling pathway but also carcinogenic potency in male medaka.

DOI： 10.1002/jat.3098

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掲載種別：研究論文（学術雑誌）  

© 2015 John Wiley & Sons, Ltd. Lithium (Li) has been widely used to treat bipolar disorder, and industrial use of Li has been increasing; thus, environmental pollution and ecological impacts of Li have become a concern. This study was conducted to clarify the potential biological effects of LiCl and Li2CO3 on a nematode, Caenorhabditis elegans as a model system for evaluating soil contaminated with Li. Exposure of C. elegans to LiCl and Li2CO3 decreased growth/maturation and reproduction. The lowest observed effect concentrations for growth, maturation and reproduction were 1250, 313 and 10 000μm, respectively, for LiCl and 750, 750 and 3000μm, respectively, for Li2CO3. We also investigated the physiological function of LiCl and LiCO3 in C. elegans using DNA microarray analysis as an eco-toxicogenomic approach. Among approximately 300 unique genes, including metabolic genes, the exposure to 78μm LiCl downregulated the expression of 36 cytochrome P450, 16 ABC transporter, 10 glutathione S-transferase, 16 lipid metabolism and two vitellogenin genes. On the other hand, exposure to 375μm Li2CO3 downregulated the expression of 11 cytochrome P450, 13 ABC transporter, 13 lipid metabolism and one vitellogenin genes. No gene was upregulated by LiCl or Li2CO3. These results suggest that LiCl and Li2CO3 potentially affect the biological and physiological function in C. elegans associated with alteration of the gene expression such as metabolic genes. Our data also provide experimental support for the utility of toxicogenomics by integrating gene expression profiling into a toxicological study of an environmentally important organism such as C. elegans.

DOI： 10.1002/jat.3058

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掲載種別：研究論文（学術雑誌）  

Androgens are essential for the development, reproduction, and health throughout the life span of vertebrates, particularly during the initiation and maintenance of male sexual characteristics. Androgen signaling is mediated by the androgen receptor (AR), a member of the steroid nuclear receptor superfamily. Mounting evidence suggests that environmental factors, such as exogenous hormones or contaminants that mimic hormones, can disrupt endocrine signaling and function. The American alligator (Alligator mississippiensis), a unique model for ecological research in that it exhibits environment-dependent sex determination, is oviparous and long lived. Alligators from a contaminated environment exhibit low reproductive success and morphological disorders of the testis and phallus in neonates and juveniles, both associated with androgen signaling; thus, the alterations are hypothesized to be related to disrupted androgen signaling. However, this line of research has been limited because of a lack of information on the alligator AR gene. Here, we isolated A mississippiensis AR homologs (AmAR) and evaluated receptor-hormone/chemical interactions using a transactivation assay.WeshowedthatAmARresponded to all natural androgens and their effects were inhibited by cotreatment with antiandrogens, such as flutamide, p,p-dichlorodiphenyldichloroethylene, and vinclozolin. Intriguingly,wefound a spliced form of theAR from alligator cDNA, which lacks seven amino acids within the ligand-binding domain that shows no response to androgens. Finally, we have initial data on a possible dominant-negative function of the spliced form of the AR against androgen-induced AmAR.

DOI： 10.1210/en.2015-1037

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掲載種別：研究論文（学術雑誌）  

© 2015 American Chemical Society. Exposure to endocrine disrupting chemicals (EDCs) can elicit adverse effects on development, sexual differentiation, and reproduction in fish. Teleost species exhibit at least three subtypes of estrogen receptor (ESR), ESR1, ESR2a, and ESR2b; thus, estrogenic signaling pathways are complex. We applied in vitro reporter gene assays for ESRs in five fish species to investigate the ESR subtype-specificity for better understanding the signaling pathway of estrogenic EDCs. Responses to bisphenol A, 4-nonylphenol, and o,p′-DDT varied among ESR subtypes, and the response pattern of ESRs was basically common among the different fish species. Using a computational in silico docking model and through assays quantifying transactivation of the LBD (using GAL-LBD fusion proteins and chimera proteins for the ESR2s), we found that the LBD of the different ESR subtypes generally plays a key role in conferring responsiveness of the ESR subtypes to EDCs. These results also indicate that responses of ESR2s to EDCs cannot necessarily be predicted from the LBD sequence alone, and an additional region is required for full transactivation of these receptors. Our data thus provide advancing understanding on receptor functioning for both basic and applied research.

DOI： 10.1021/acs.est.5b00704

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掲載種別：研究論文（学術雑誌）  

© 2014 Elsevier Ltd. To evaluate trophic biomagnification of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in an estuary of the Ariake Sea, Japan, we measured concentrations of 209 PCB congeners and 28 PBDE congeners, and nitrogen stable isotope (δ15N) levels in living aquatic organisms. The trophic magnification factor (TMF) for σPCBs (all 209 congeners) was 1.52, and TMFs for 58 PCB congeners ranged from 0.90 to 3.28. In contrast, TMF for σPBDEs was 1.17, and TMFs for 7 PBDE congeners ranged from 0.46 to 1.66. TMFs of PCB and PBDE congeners in this study were lower than those in marine food webs, and were similar to those in a lake food web. However, although negative relationships were observed between TMF and log octanol-water partition coefficient (KOW) values among PCB congeners in this study (log KOW up to 7), positive relationships have been reported in several other studies. In the present estuary, PCB concentrations in sea bass may not reach a steady state because sea bass are migratory species. Therefore, TMFs of highly chlorinated congeners with high log KOW values take longer to reach the steady state and may not increase with increasing log KOW.

DOI： 10.1016/j.chemosphere.2014.08.066

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掲載種別：研究論文（学術雑誌）  

The constitutive androstane receptor (CAR) not only displays a high basal transcriptional activity but also acts as a ligand-dependent transcriptional factor. It is known that CAR exhibits different ligand profiles across species. However, the mechanisms underlying CAR activation by chemicals and the species-specific responses are not fully understood. The objectives of this study are to establish a high-throughput tool to screen CAR ligands and to clarify how CAR proteins from the Baikal seal (bsCAR) and the mouse (mCAR) interact with chemicals and steroid receptor coactivator 1 (SRC1). We developed the surface plasmon resonance (SPR) system to assess quantitatively the interaction of CAR with potential ligands and SRC1. The ligand-binding domain (LBD) of bsCAR and mCAR was synthesized in a wheat germ cell-free system. The purified CAR LBD was then immobilized on the sensor chip for the SPR assay, and the kinetics of direct interaction of CARs with ligand candidates was measured. Androstanol and androstenol, estrone, 17β-estradiol, TCPOBOP, and CITCO showed compound-specific but similar affinities for both CARs. The CAR-SRC1 interaction was ligand dependent but exhibited a different ligand profile between the seal and the mouse. The results of SRC1 interaction assay accounted for those of our previous in vitro CAR-mediated transactivation assay. In silico analyses also supported the results of CAR-SRC1 interaction; there is little structural difference in the ligand-binding pocket of bsCAR and mCAR, but there is a distinct discrimination in the helix 11 and 12 of these receptors, suggesting that the interaction of ligand-bound CAR and SRC1 is critical for determining species-specific and ligand-dependent transactivation over the basal activity. The SPR assays demonstrated a potential as a high-throughput screening tool of CAR ligands. © The Author 2012. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved.

DOI： 10.1093/toxsci/kfs288

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記述言語：英語   出版者・発行元：日本食品化学学会  

ペット飼料中に存在する植物エストロゲンと塩素系農薬は、共にバイオアッセイによりエストロゲン作用をもたらす可能性があると考えられる。我々は、様々な市販ペット飼料中の、植物エストロゲン、塩素系農薬とエストロゲン活性を調査し、エストロゲン活性への潜在的な寄与を、以前と比較し検討した。β-グルクロニダーゼによる加水分解後、genisteinとdaidzeinは検出された。これらの結果は以前の結果と同等であった。さらに、α-HCH、β-HCH、HCB、p,p'-DDE、dieldrinは、テストした15種の飼料中2つで検出された。全ての飼料で、イーストベース生物検定法では、α(ERα)より高いエストロゲン受容体β(ERβ)の活性化レベルを示した。これらの結果は、植物エストロゲン(たとえば、genisteinとdaidzein)がエストロゲン活性に寄与している主な物質であることを示している。さらに、5飼料の植物エストロゲン濃度は、重要なエストロゲン活性を生じるに十分な量と推定された。

DOI： 10.18891/jjfcs.20.1_22

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掲載種別：研究論文（学術雑誌）  

Our previous studies have detected high levels of dioxins and related compounds (DRCs) including polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), and coplanar PCBs (Co-PCBs) in the black-footed albatross (BFA), Phoebastria nigripes, from the North Pacific region. We have also cloned two aryl hydrocarbon receptors, AHR1 and AHR2, of the BFA. To evaluate the sensitivity to DRCs in the BFA and to assess the status of cytochrome P450 1A (CYP1A) induction in the wild population, this study investigated the mRNA expression levels of BFA AHR1 and AHR2 and also the transactivation potencies of each AHR by 15 selected DRC congeners. Quantitative real-time PCR of BFA AHR mRNAs showed that hepatic AHR1 is more highly expressed than AHR2. Transactivation by graded concentrations of individual DRCs was measured in COS-7 cells, where BFA AHR1 or AHR2 was transiently transfected. For congeners that exhibited AHR-mediated dose-dependent activities, 50% effective concentration (EC 50) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) relative potencies (REPs) were estimated. Based on the estimates of the REPs, TCDD induction equivalency factors (IEFs) were determined. For BFA AHR1, PeCDF was equipotent to TCDD, but other congeners exhibited lower IEFs. For BFA AHR2, PCDD/F congeners except OCDD/F showed IEFs 1.0. Using BFA AHR1- or AHR2-IEFs and hepatic concentrations of DRCs in North Pacific BFAs, TCDD induction equivalents (IEQs) were calculated. We further constructed nonlinear regression models on the relationships between BFA AHR1- or AHR2-IEF derived total IEQ or WHO-TEF derived total TEQ and ethoxyresorufin-O-deethylase activity (EROD) in the liver of wild BFAs. The results indicated that the relationships of BFA AHR1- and AHR2-based IEQs and EROD were predictable from BFA AHR1- and AHR2-mediated transactivation by TCDD, respectively. Collectively, these results suggest that the in vitro assay incorporating the AHR of species of concern would be a useful tool to predict the sensitivity to DRCs in the species and CYP1A induction in the wild population. © 2011 American Chemical Society.

DOI： 10.1021/es2028263

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

The present study assessed the transactivation potencies of the Baikal seal (Pusa sibirica) peroxisome proliferator-activated receptor α (BS PPARα) by perfluorochemicals (PFCs) having various carbon chain lengths (C4-C12) using an in vitro reporter gene assay. Among the twelve PFCs treated with a range of 7.8-250 μM concentration, eight perfluoroalkyl carboxylates (PFCAs) and two perfluoroalkyl sulfonates (PFSAs) induced BS PPARα-mediated transcriptional activities in a dose-dependent manner. To compare the BS PPARα transactivation potencies of PFCs, the present study estimated the PFOA induction equivalency factors (IEFs), a ratio of the 50% effective concentration of PFOA to the concentration of each compound that can induce the response corresponding to 50% of the maximal response of PFOA. The order of IEFs for the PFCs was as follows: PFOA (IEF: 1) > PFHpA (0.89) > PFNA (0.61) > PFPeA (0.50) > PFHxS (0.41) > PFHxA (0.38) ≈ PFDA (0.37) > PFBA (0.26) = PFOS (0.26) > PFUnDA (0.15) ≫ PFDoDA and PFBuS (not activated). The structure-activity relationship analysis showed that PFCAs having more than seven perfluorinated carbons had a negative correlation (r = -1.0, p = 0.017) between the number of perfluorinated carbons and the IEF of PFCAs, indicating that the number of perfluorinated carbon of PFCAs is one of the factors determining the transactivation potencies of the BS PPARα. The analysis also indicated that PFCAs were more potent than PFSAs with the same number of perfluorinated carbons. Treatment with a mixture of ten PFCs showed an additive action on the BS PPARα activation. Using IEFs of individual PFCs and hepatic concentrations of PFCs in the liver of wild Baikal seals, the PFOA induction equivalents (IEQs, 5.3-58 ng IEQ/g wet weight) were calculated. The correlation analysis revealed that the hepatic total IEQs showed a significant positive correlation with the hepatic expression levels of cytochrome P450 4A-like protein (r = 0.53, p = 0.036). This suggests that our approach may be useful for assessing the potential PPARα-mediated biological effects of complex mixtures of PFCs in wild Baikal seal population. © 2011 American Chemical Society.

DOI： 10.1021/es103748s

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掲載種別：研究論文（学術雑誌）  

We examined the combined estrogenic activity of soybean extract used in a dietary supplement and ethinyl estradiol (EE) contained in an oral contraceptive. Olive oil (control), soybean extract (0.0036 or 0.36 g/kg corresponding to doses of total isoflavone of 0.83 or 83 mg/kg respectively), EE (1 or 10 μg/kg), and soybean extract+EE were administered to ovariectomized CD-1 mice by oral gavage for 4 consecutive days. Soybean extract (0.0036 or 0.36 g/kg) and EE (1 μg/kg) did not increase the relative uterine weight. The relative uterine weight of the soybean extract (0.0036 or 0.36 g/kg)+EE (10 μg/kg) group was significantly higher than that of the control. The relative uterine weight of the soybean extract (0.36 g/kg)+ EE (10 μg/kg) group was also significantly higher than that of the EE (10 μg/kg) group. Soybean extract showed estrogenic activity for human estrogen receptor (hER)-α and-β. Coadministration of EE with soybean extract increased the estrogenic activity for hER-α and-β.

DOI： 10.3358/shokueishi.51.101

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掲載種別：研究論文（学術雑誌）  

Livestock wastewater is treated by activated sludge treatment. Untreated livestock wastewater has high estrogen activity because animal excreta contains estrogen. When activated sludge treatment is applied, the estrogen activity declines or is lost. However, the color of treated livestock wastewater is deep brownish-red because of the decomposition of organic compounds or the synthesis of metabolites. Discharging colored wastewater to the environment could cause some problems, so it is necessary to decolorize colored wastewater before it is discharged. It has been suggested that electrolysis decolorization technology is suitable for treating colored wastewater; however, the process produces volatile organic compounds (VOCs). In fact, little research has been conducted with reference to estrogen activity in wastewater that has undergone electrolysis, especially on the contribution of the electrolysis decolorization process to estrogen activity, i.e., the possibility of resynthesis of some substance with estrogen activity due to resolved and metabolized colored components. In this study, the concentration of VOC was measured for various electrolysis conditions, and estrogen activity was examined using a yeast two-hybrid assay. From the results, decolorization of colored livestock wastewater by electrolysis was possible, and the VOC generation during electrolysis could be controlled depending on the electrolysis conditions. Estrogen activity in colored livestock wastewater disappeared on electrolysis decolorization. © 2010 Springer Japan.

DOI： 10.1007/s10163-009-0273-1

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記述言語：英語   出版者・発行元：Japan Society for Environmental Chemistry  

The present study demonstrates the seasonal variations of concentrations of pharmaceutical and personal care products(PPCPs) in influents and effluents at two sewage treatment plants (STPs) and the surface water of Mankyung River, South Korea. PPCPs were measured using a high performance liquid chromatograph coupled with a tandem mass spectrometer(LC-MS/MS). In the two STPs surveyed, all of the 13 targeted PPCPs were detected at concentrations ranging from ND (not detected) to 13700 ng/L in the influents, and ND to 1940 ng/L in the effluents, with total PPCP concentrations being higher in winter than in other seasons in both STP influents and effluents. While the removal efficiencies of disopyramide, ibuprofen, triclosan, erythromycin, atenolol and indomethacin of the STPs were relatively high (average 60-90%), those of clarithromycin, carbamazepine, fluconazole, propranolol and ifenprodil were extremely low (average 0-30%).The prevalent contaminants in the river water in all seasons were carbamazepine (ND to 595 ng/L), followed by atenolol (ND-690 ng/L), ibuprofen (ND-414 ng/L), mefenamic acid (ND-326 ng/L), levofloxacin (ND-380 ng/L), clarithromycin(ND-443 ng/L), fluconazole (ND-111 ng/L), erythromycin (ND-152 ng/L), propranolol (ND-268 ng/L), ifenprodil (ND-38.5 ng/L), indomethacin (ND-58.2 ng/L), triclosan (ND-46.1 ng/L) and disopyramide (ND). Concentrations of PPCPs in surface river water collected from five sample sites trended to be higher in November than in March, May and August. It was proposed that the reasons for the observed seasonal variations in PPCP concentrations may be increased consumption by the inhabitants of the Mankyung River basin and the decreased river flow during this period leading to increased relative concentrations of these compounds in water. In addition, PPCP concentrations were greater in the surface water samples collected in the vicinity of STPs, so STPs act as a point source of PPCP pollution.

DOI： 10.5985/jec.20.127

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00353265637?from=CiNii

掲載種別：研究論文（学術雑誌）  

Vitellogenin (VTG) is a useful biomarker for detecting the estrogenic activity of chemicals in aquatic environments. However, little information is available on the regulatory mechanisms of the expression of each VTG subtype, particularly the relationship between expression patterns of VTG1/2 and estrogen receptor (ER) subtypes, such as ERα and ERβ. In this paper, we measured VTG1 and VTG2 mRNA induction in male medaka liver, which was treated with ERα-selective ligand, (17α, 20E)-3-hydroxy-17,20-[(1- methoxyethylidene)bis(oxy)]-19-norpregna-1,3,5(10),20-tetraene-21-carboxylic acid, methyl ester or ERβ-selective ligand, 2-(4-hydroxyphenyl)-5-hydroxy- 1,3-benzoxazole and investigated the characteristics of ER subtype function in VTG1 and VTG2 inductions. Hepatic VTG1 mRNA was induced by ERα-selective ligands at even low concentration and maximum increases were the same as for E2. VTG2 mRNA was also increased, but its levels were very low. On the other hand, ERβ-selective ligands significantly increased VTG2 mRNA in the presence of ERα agonists. These results indicate that the expression of each VTG subtype is regulated by unique ER subtypes. VTG1 expression is only regulated by the action of ERα. In contrast, VTG2 expression is regulated by both ERα and ERβ, with ERα being essential for VTG2 gene expression and ERβ being essential for enhancement. ©2009 The Pharmaceutical Society of Japan.

DOI： 10.1248/jhs.55.930

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掲載種別：研究論文（学術雑誌）  

Pharmaceutical and personal care products (PPCPs) enter aquatic environments via sewage treatment facilities and their potentially toxic effects on biota, particularly aquatic organisms, are of considerable concern. In this study, we investigated the acute toxicity of selected PPCPs on a freshwater crustacean (Thamnocephalus platyurus) and a fish species (Oryzias latipes). The 24-hr median lethal concentration (LC50) values of ibuprofen, mefenamic acid, indometacin, carbamazepine, propranolol, ifenprodil, clarithromycin and triclosan for T. platyurus were estimated to be 19.59, 3.95, 16.14, > 100, 10.31, 4.43, 94.23 and 0.47 mg/l respectively. Conversely, the 96-hr LC50 values for these PPCPs were estimated at > 100, 8.04, 81.92, 45.87, 11.40, 8.71, > 100 and 0.60 mg/l for O. latipes, respectively. The toxic sensitivity of T. platyurus to these PPCPs, except for carbamazepine, was therefore higher than for O. latipes. No acute toxicity effects were associated with PPCPs, such as atenolol, disopyramide, famotidine, fluconazole, erythromycin and levofloxacin, in the two aquatic organisms at the concentrations tested in this study (> 100 mg/l). These findings may help us to understand the potential biological effects and risks associated with PPCP exposure in aquatic organisms. Further long-term studies are required to fully assess the growth and reproduction of these compounds on aquatic biota.

DOI： 10.2131/jts.34.227

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掲載種別：研究論文（学術雑誌）  

We investigated the effects of environmentally relevant concentrations of nonylphenol (NP) on survival, growth, sexual development and molting of the mysid Americamysis bahia (Crustacea: Mysidacea), including assay of 20-hydroxyecdysone (20E) levels. Seven-day-old mysids were exposed to NP concentrations of 0.3, 1, 3, 10 and 30 μg/L for 14 days. Among growth-related traits we assayed, an effect on body length was the most prominent, with the effects observed at concentrations as low as 1 μg/L NP. In addition, the total number of molting exposed to NP for 14 days was significantly decreased in the treatment groups at 10 or 30 μg/L relative to the controls. These results clearly indicate that subchronic exposure to environmentally relevant concentrations of NP affects growth of mysids. Furthermore, we investigated the effect of NP on production of 20E in female mysids during the molting period. Production of 20E in pre-molting mysids exposed to 30 μg/L of NP was lower than those in control groups, and exposure of female mysids to NP disrupted molting cycles. Taken together, the results suggest that environmentally relevant concentrations of NP can disrupt growth of A. bahia via inhibition of 20E levels and an associated delay in molting. © 2008 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.cbpc.2008.09.005

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掲載種別：研究論文（学術雑誌）  

The present study demonstrates the occurrence of pharmaceuticals and personal care products (PPCPs) in surface water from the Mankyung River, South Korea. Samples collected at 5 Sites along theMankyung River were assayed using a liquid chromatograph coupled with a tandem mass spectrometer (LC/MS/MS) for 13 PPCPs. Overall, 11 out of the 13 selected PPCPs, which span a range of therapeutic classes and one personal care product, were detected in surface water samples collected from the Mankyung River. The most prevalent contaminants were ibuprofen, with average concentrations ranging from not detected (ND) to 414 ng/l, followed by carbamazepine (ND- 595 ng/l), atenolol (ND-690 ng/l), clarithromycin (ND-443 ng/l), mefenamic acid (ND-326 ng/l), erythromycin (ND-137 ng/l), fluconazole (ND-111 ng/l), levofloxacin (ND-87.4 ng/l), indomethacin (ND-33.5 ng/l), propranolol (ND-40.1 ng/l), ifenprodil (ND-35.4 ng/l), disopyramide (ND) and triclosan (ND). PPCP concentrations were highest in surface water samples collected downstream from a sewage treatment plant (STP), implying possibly insuf- ficient removal efficiency of the PPCPs in the STP. Contamination by PPCPs such as ibuprofen, carbamazepine, atenolol, mefenamic acid and clarithromycin was high in the Mankyung River compared to concentrations in other countries.

DOI： 10.1248/jhs.55.249

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

This study demonstrates the effects of synthetic polycyclic musks such as Galaxolide (HHCB), Tonalide (AHTN), Traseolide (ATII), Celestolide (ADBI), Phantolide (AHMI) and Cashmeran (DPMI), both on the early life stage and on gene expression in the livers of male medaka (Oryzias latipes). The toxicity ranking (the 96-h median lethal concentration) of the chemicals tested on 24-h-old medaka larvae descended in the order HHCB (0.95 mg/L) = ATII (0.95 mg/L) > AHTN (1.0 mg/L) > AHMI (1.2 mg/L) > ADBI (2.0 mg/L) ≫ DPMI (12 mg/L), indicating high acute toxicity of these compounds on the early life stages of medaka. Expression analysis of hepatic vitellogenin (VTG) protein showed potential estrogenic effects upon the addition of AHTN and HHCB, indicative of the induction of VTG synthesis in the livers of male medaka. We also investigated mRNA expression levels of two estrogen receptor (ER) subtypes (ERα and β), two VTGs (VTG I and II), pregnane X receptor (PXR), and two cytochromes P450 (CYP) 3As (CYP3A38 and 3A40) in the livers of male medaka treated with AHTN and HHCB at 5, 50 and 500 μg/L. Quantitative real-time PCR analyses revealed that hepatic ERα, VTG I, VTG II, and CYP3A40 mRNA responded to 500 μg/L of AHTN and/or HHCB after 3 days exposure, whereas no effects of these compounds on ERβ, PXR, and CYP3A38 mRNA transcription were observed. These results suggest that certain polycyclic musks, including AHTN and HHCB, induce the expression levels of hepatic ERα and VTG mRNA/protein and modulate expression levels of CYP3A40 mRNA in the livers of male medaka. © 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aquatox.2008.09.007

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掲載種別：研究論文（学術雑誌）  

Menadione, a synthetic vitamin K3, exhibits anti-estrogenic activity on in vitro assay. However, the in vivo anti-estrogenic effects of menadione have not been determined, while correlations between biological effects and structural changes are unclear. Thus, we investigated the in vivo anti-estrogenic activity of menadione under fluorescent light and dark conditions. Suppression of the hepatic estrogen response genes vitellogenin1 (VTG1), VTG2 and estrogen receptor-α (ER-α) was used as an index of antiestrogenic activity. Male medaka (Oryzias latipes) were treated with nominal concentrations of menadione in the presence or absence of 17β-estradiol (E2), and hepatic VTG1, VTG2 and ER-α mRNA levels were determined by quantitative real-time PCR. In the presence of E2 under dark conditions, expression of hepatic VTG2 and ER-α genes was suppressed by menadione treatment. On the other hand, menadione activity was lost under fluorescent light conditions. These results suggest that menadione has antiestrogenic activity in vivo, and that this activity is diminished under fluorescent light, probably due to a structural change in menadione.

DOI： 10.1248/jhs.54.596

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記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

Here we report on the in vivo estrogenic effects of two fluorotelomer alcohols, such as 1H,1H,2H,2H-perfluorooctan-1-ol (6:2 FTOH) and 1H,1H,2H,2H-perfluorodecan-1-ol (8:2 FTOH), in male medaka (Oryzias latipes). An in vitro yeast two-hybrid assay indicated a significant, dose-dependent interaction between medaka estrogen receptor α (ERα) and coactivator TIF2 upon treatment with 6:2 FTOH, 8:2 FTOH or 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-nonadecafluoro-1-decanol (NFDH). The relative ranks of tested chemicals on the estrogenic effects for medaka ERα descended in the order of estradiol-17β (100) ≫ 6:2 FTOH (0.16) > NFDH (0.016) > 8:2 FTOH (0.0044). In contrast, no interaction with the ERα was observed upon treatment with perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDA) or perfluoroundecanoic acid (PFUnDA). Expression analysis of hepatic vitellogenin (VTG) protein showed estrogenic potentials with, 6:2 FTOH and 8:2 FTOH, indicative of the induction of VTG synthesis in the livers of male medaka. We also investigated mRNA expression levels of two ER subtypes (ERα and β) and two VTGs (VTG I and VTG II) in the livers of male medaka following exposure to FTOHs. Quantitative real-time polymerase chain reaction analyses revealed that hepatic ERα, VTG I, and VTG II mRNA responded rapidly to FTOHs such as 6:2 FTOH and 8:2 FTOH after 8-h exposure, whereas no effects of these compounds on ERβ mRNA transcription were observed. These results from both in vitro and in vivo assays strongly suggest that certain FTOHs, such as 6:2 FTOH and 8:2 FTOH, induce hepatic VTG through activation of ERα in male medaka. © 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2008.01.065

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掲載種別：研究論文（学術雑誌）  

Seasonal and diurnal fluctuations in pharmaceuticals and personal care products (PPCPs) concentrations in residential sewage water were ascertained in an area with no businesses industry (e.g., plants or offices) upstream. PPCPs with high detection rates included ibuprofen, acetaminophen and indomethacin (antipyretic analgesics), atenolol and disopyramide (antiarrhythmics), clarithromycin (antibiotic), levofloxacin (synthetic antimicrobial agent) and triclosan (disinfectant). In summer, the concentration of triclosan was the highest, while in winter, the concentrations of ibuprofen and acetaminophen were higher than the others. Moreover, three types of diurnal fluctuations were observed: no marked diurnal changes (triclosan), high daytime concentrations (disopyramide) and high nighttime concentrations (acetaminophen).

DOI： 10.1248/jhs.54.240

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

To investigate the biological effects of perfluorochemicals (PFCs) and to identify biomarkers of exposure to PFCs, this study focused on the effects mediated by peroxisome proliferator-activated receptor α (PPARα) in Baikal seals (Pusa sibirica). We cloned a full-length cDNA, encoding PPARα from the liver of Baikal seal, which has a deduced open reading frame of 468-amino acid residues with a predicted molecular mass of 52.2 kDa. Comparison of the amino-acid sequence of Baikal seal PPARα with that of other mammalian PPARα showed considerable similarities with PPARα of dog (97%), human (95%), rat (92%), and mouse (91%). The quantitative real-time RT-PCR analyses of tissues from Baikal seals revealed that PPARα mRNAs were primarily expressed in the liver, kidney, heart, and muscle. The hepatic expression levels of PPARα mRNA showed a positive correlation with the expression levels of immunochemically detected cytochrome P450 (CYP) 4A-like protein, indicating that the PPARα-CYP4A signaling pathway in Baikal seal is likely conserved. This study also developed an in vitro PPARα reporter gene assay using African green monkey kidney CV-1 cells transiently transfected with Baikal seal PPARα cDNA expression vector and a reporter vector containing a peroxisome proliferator-responsive element. The in vitro reporter gene assay displayed significant response to clofibrate, which is a known PPARα agonist in humans and rodents. Treatment with perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), or perfluorooctane sulfonate (PFOS) induced PPARα-mediated transcriptional activity in a dose-dependent manner, showing the lowest-observed-effect concentrations of 62.5, 125, 125, 62.5, and 125 μM, respectively. In the livers of wild Baikal seals, expression levels of PPARα mRNA showed a significant positive correlation with PFNA levels. Moreover, expression of hepatic CYP4A-like protein was significantly correlated with the hepatic concentrations of PFNA and PFDA. These results suggest modulation of the PPARα-CYP4A signaling pathway by PFCs in the wild Baikal seals. Our study demonstrates that the PPARα-mediated response may be a useful biomarker to evaluate potential biological effects of PFCs in wildlife. © 2008 American Chemical Society.

DOI： 10.1021/es0720558

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

Concentrations of perfluorochemicals (PFCs) including perfluoroalkylsulfonates (PFSAs) and perfluoroalkylcarboxylates (PFCAs) were determined in liver and serum of Baikal seals (Pusa sibirica) collected from Lake Baikal, Russia in 2005. Among the 10 PFC compounds measured, perfluorononanoic acid (PFNA, 3.3-72 ng/g wet wt) concentrations were the highest in liver, followed by perfluorooctanesulfonate (PFOS, 2.6-38 ng/g). The accumulation profile of long-chain (C7-C12) PFCAs in particular, the predominance of PFNA, indicated that 8:2 fluorotelomer alcohol or commercially manufactured PFNA is a major local source of PFCs in Lake Baikal. No gender-related differences in the concentrations of individual PFCs or total PFCs were found. Tissues from pups and juveniles contained relatively higher concentrations of PFCs than tissues from subadults and adults, suggesting that maternal transfer of PFCs is of critical importance. Comparison of concentrations of PFCs in livers and sera collected from the same individuals of Baikal seals revealed that residue levels of PFOS, PFNA, perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were significantly higher in liver than in serum. The concentration ratios of PFNA and PFDA between liver and serum were calculated to be 14 and 15, respectively, whereas the ratio of PFDS was 2.4. This suggests preferential retention of both PFNA and PFDA in liver. Concentrations of PFDS, PFNA, and PFDA in liver were significantly correlated with those in serum, whereas concentrations of PFUnDA were not correlated in between the two tissues, suggesting differences in pharmacokinetics among these PFCs. Temporal comparisons of hepatic PFC concentrations in seals collected between 1992 and 2005 showed that the concentrations of PFDS (p = 0.0006), PFNA (p = 0.061) and PFDA (p = 0.017) were higher in animals collected in recent years, indicating ongoing sources of PFC contamination in Lake Baikal. © 2008 American Chemical Society.

DOI： 10.1021/es072054f

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記述言語：英語   出版者・発行元：日本環境毒性学会  

CiNii Books

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

The present study demonstrates the estrogenic effects of fluorotelomer alcohols (FTOHs). In a yeast two-hybrid assay, treatment with 1H,1H,2H,2H-perfluorooctan-1-ol (6:2 FTOH), 1H,1H,2H,2H-perfluoro-decan-1-ol (8:2 FTOH) and 2,2,3,3,4,-4,5,5,6,6,7,7,8,8,9,9,10,10,10-nonadecafluoro-1- decanol (NFDH) showed a dose-dependent interaction between the human estrogen receptor (hER) isoforms hERα or hERβ ligand-binding domain and coactivator TIF2, whereas there were no estrogenic effects of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) for these hERs. The estrogenic effects of FTOHs on hERα were higher than those on hERβ, indicating a differential responsiveness of hERs to FTOHs. The relative ranks of tested chemicals on the estrogenic effects for hERα and hERβ descended in the order of estradiol-17β⋙6:2 FTOH> NFDH>8:2 FTOH. These results suggest that certain FTOHs including 6:2 FTOH, 8:2 FTOH and NFDH interact with hER isoforms α and β in vitro. Further studies are necessary to investigate contamination levels, potential biological effects and the risks of these compounds on human health. © 2007 Pharmaceutical Society of Japan.

DOI： 10.1248/bpb.30.1358

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掲載種別：研究論文（学術雑誌）  

To investigate endocrine disruption and chemical contaminant levels in the aquatic environment, serum vitellogenin (Vtg) induction, steroid hormone synthesis, gonad histopathology and nonylphenol (NP) bioaccumulation were measured in common carp (Cyprinus carpio) in three sites (two rivers and one lake, in which high, medium, and low NP concentrations were detected in a previous study) in Japan from November 2001 to February 2002. The average gonadosomatic indexes (GSIs) for males were 3.9% in the Ishizu River, 5.6% in the Imba discharge channel, and 4.2% in Teganuma. No testis-ova in the gonads were found in any of the captured carp in this study. Abnormalities in testis were observed in individuals (n = 2/15) captured in the Imba discharge channel, and retraction and unusual cell proliferation were observed in the testis of the same fish. Serum Vtg was detected in 40% of the male samples captured in the Ishizu River and in 53% of the male samples captured in the Imba discharge channel. The levels of alkylphenols and bisphenol A, as well as estrogenic activity, were determined in the aquatic environment. In additional caging experiments in the Nikko River (medium NP concentration), male carp showed NP bioconcentration after the exposure to the river water.

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掲載種別：研究論文（学術雑誌）  

Synthetic musk fragrance compounds, such as polycyclic musks (PCMs), are a group of chemicals used extensively as personal care products, and can be found in the environment and the human body. PCMs, such as 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexa-methylcyclopenta-gamma-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyltetralin (AHTN), are known to have agonistic activities toward human estrogen receptor alpha (hERalpha) and hERbeta, and have antagonistic activity toward the human androgen receptor (hAR), as shown in several reporter gene assays. However, little is known about the interaction of PCMs with the human thyroid hormone receptor (hTR), and the hormonal effects of other PCMs except for HHCB and AHTN. In this study, we focus on the interactions of six PCMs, namely, HHCB, AHTN, 4-acetyl-1,1-dimethyl-6-tert-butyl-indan (ADBI), 6-acetyl-1,1,2,3,3,5-hexamethylindan (AHMI), 6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)-indanone (DPMI), and 5-acetyl-1,1,2,6-tetramethyl-3-isopropy-lindan (ATII) with hERalpha, hAR, and hTRbeta by in vitro reporter gene assay using Chinese hamster ovary cells. All the samples were found to be agonists toward hERalpha, whereas no agonistic activities of these PCMs for hAR and hTRbeta were observed. No antagonistic activities for hERalpha and hTRbeta were observed at the concentrations tested. However, several PCMs, namely, HHCB, AHTN, ATII, ADBI, and AHMI, showed dose-dependent antagonistic activities for hAR, and the IC50 values of these compounds were estimated to be 1.0 x 10(-7), 1.5 x 10(-7), 1.4 x 10(-7), 9.8 x 10(-6), and 1.4 x 10(-7) M, respectively. The results suggest that these PCMs interact with hERalpha and hAR but have no hormonal effect on hTRbeta. This is the first report on the agonistic and antagonistic activities of ATII, ADBI, AHMI, and DPMI for hERalpha and hAR as determined by in vitro reporter gene assay using stably transfected Chinese hamster ovary cells.

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

The objective of this study was to investigate the reproductive success (fertility and fecundity) of medaka (Oryzias latipes) exposed to 4-nonylphenol (4-NP) in water and the viability of their F1 offspring. In addition, we measured the bioconcentration of 4-NP in eggs. After a 21-d exposure to 100 μg/l 4-NP, medaka showed reduced egg production and fertility. Hepatic vitellogenin levels were increased significantly in males treated with 10, 50 and 100 μg/l of 4-NP. In the F1 generations, the hatchability and time to hatching of embryos in the 100 μg/l treatment group were adversely affected, and 2-7 μg 4-NP/g egg was found in spawned eggs (the bioconcentration factor: 30-100). These results indicate that (1) 4-NP adversely affected the reproduction (fecundity and fertility) of adult medaka, (2) 4-NP accumulated in eggs through maternal transfer and (3) these levels of 4-NP were associated with adverse effects in the F1 offspring. © 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2006.03.034

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掲載種別：研究論文（学術雑誌）  

The polymerization initiators for resins cured using visible light usually consist of a photosensitizer, primarily camphorquinone (CQ), and a reducing agent, which is often a tertiary amine (DMPT, DMAEMA), while the initiator used for self-curing resins consists of benzoyl peroxide (BPO) and a tertiary amine (DMPT). The genotoxicities of camphorquinone (CQ), benzoyl peroxide (BPO), dimethyl-para-toluidine (DMPT), 2-dimethylamino-ethyl-methacrylate (DMAEMA), and 1-allyl-2-thiourea (ATU) were examined using the bioluminescent bacterial genotoxicity test. 4-Nitroquinoline-N-oxide (4NQO) was prepared for comparison with these chemicals. Acetone solutions of the five polymerization initiators and 4NQO were prepared. Benzoyl peroxide (BPO), dimethyl-para-toluidine (DMPT), and 1-allyl-2-thiourea (ATU) showed significant genotoxic activity at 24 h in the bioluminescent bacterial genotoxicity test, at concentrations of approximately 5 μM, 4 mM, and 1 mM, respectively. 2-Dimethyloamino-ethyl- methacrylate (DMAEMA) did not have genotoxic activity and CQ had questionable genotoxic activity. In comparison, 4NQO had strong genotoxicity, at 4 μM, roughly the same as that of BPO. Therefore, BPO should be used carefully in clinical dentistry. © 2006 Springer Science + Business Media, Inc.

DOI： 10.1007/s10856-006-6326-2

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掲載種別：研究論文（学術雑誌）  

A low-estrogenic diet for goldfish Carassius auatus was produced for an in vivo estrogen activity test, because commercial fish feed has estrogenic activity and may affect the results of estrogen assays. The newly produced diet (FD5) was formulated with defatted rice bran and casein, and did not contain any soybean meal or fish meal. Phytoestrogen contents (genistein, daidzein, equol, and coumestrol) of FD5 were measured by liquid chromatography-mass spectroscopy/mass spectroscopy (LC-MS/MS) and compared with those of the commercial trout diet (TD) and carp diet (CD). The genistein, daidzein, and coumestrol contents of TD and CD were much higher (5-2000 times) than those of FD5, but equol was detected only in FD5. Estrogenic activity of the fish diets was estimated in vitro by the yeast estrogen-screen assay (YES assay). The estrogenic activity was detected in TD and CD, but not in FD5. The in vivo estrogenic activity of the diets was examined by determining the production of vitellogenin in male goldfish. When male goldfish were fed TD or CD, plasma vitellogenin levels increased, but fish that were fed FD5 maintained low vitellogenin levels. These results indicate that FD5 produced in the present study has a low estrogenic activity, and FD5 would be suitable for the in vivo estrogen activity test using goldfish.

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掲載種別：研究論文（学術雑誌）  

The oxidative photodegradation behaviors of selected polychlorinated biphenyls (PCBs) [2,3,3′,4′-tetraCB (BZ number: CB56), 2,3′,4′,5-tetraCB (CB70), and 3,4,4′,5-tetraCB (CB81: coplanar PCB)] using titanium dioxide (TiO2) in water were investigated. The main purposes were to clarify the structural relation between the original PCBs and the intermediates derived by TiO2 oxidation and to evaluate the estrogenic activity in the treated PCBs during the oxidative reactions. Approximately 90% of the three tetraCBs decomposed within 120 min. Intermediates by decomposition of three tetraCBs, such as some OH-tetraCBs and OH-triCBs, carboxylic intermediates, phenolic intermediates, and other intermediates produced by the cleavage of a benzene ring were identified and quantified. In the degradation pathways, the produced amounts of OH-tetraCB and OH-triCB increased within 60 min of irradiation time. Estrogenic activities of the intermediates from the three tetraCBs in water were assessed by using a yeast two-hybrid assay system for human estrogen receptor α (hERa). The maximal estrogenic activities were induced by the solutions of decomposed CB81 with irradiation time at 60 min. We found that the solutions at an irradiation time of 60-120 min contained several 4-OH-tetraCBs and 4-OH-triCBs substituted with OH and CI at para- and para′-positions. It is presumed that the chemical structures of the 4-OH-PCBs are similar to that of 17β-estradiol (β-E2); these intermediates present strong estrogenic activities. Moreover, we learned that there is a high possibility of conversion from some low toxic PCBs congeners to strong estrogenic OH-PCBs. © 2005 American Chemical Society.

DOI： 10.1021/es050791a

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担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）  

In a recent study, it was reported that 4-methyl-2,4-bis(4-hydroxyphenyl) pent-1-ene (MBP), a metabolite of bisphenol A (BPA; 2,2-bis(4-hydroxyphenyl) propane), showed estrogenic activity in several in vitro assays, and the estrogenic activity of MBP was higher than that of BPA. In this study, we have investigated the early life stage toxicity and estrogenic effect of MBP on medaka (Oryzias latipes). The 96-h median lethal concentration value of MBP and BPA with 24-h-old larvae was estimated to be 1640 and 13,900 μg/l, respectively. The hatchability of fertilized eggs exposed to MBP and BPA over 14 days was significantly decreased at doses of 2500 μg/l and 12,500 μg/l, respectively. Moreover, to compare the potency of estrogenic activity in vivo, male medaka were exposed to various concentrations of MBP and BPA for 21 days. The lowest-observed-effect concentrations of MBP and BPA for hepatic vitellogenin induction in male medaka were estimated to be 4.1 and 1000 μg/l, respectively. These results suggest that MBP has high toxicity for early life stages of the medaka, and that the estrogenic activity of MBP was about 250-fold higher than that of BPA to male medaka. © 2005 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.lfs.2005.03.025

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掲載種別：研究論文（学術雑誌）  

We investigated the effects of nonylphenol (NP) and triclosan (TCS) on production of vitellogenin (Vg), testosterone (T), and hepatic cytochrome P450 1A and 2B activities in male South African clawed frogs (Xenopus laevis). In a 14-d waterborne exposure test, no significant differences in the level of plasma Vg synthesis in male frogs were observed among the control, 10, 50, and 100 μg/l NP and 20, 100, and 200 μg/l TCS treatment groups. Intraperitoneal injection of male frogs with 2, 20, and 200 μg/g body weight NP resulted in no significant differences in plasma Vg levels among the control and all treatment groups. However, the levels of plasma Vg in all TCS treatment groups (intraperitoneal injection of 4, 40, and 400 μg/g body weight) were lower than that in the solvent control group, and male frogs injected with high doses of NP or TCS had lower T levels than the control group. No significant differences in hepatic cytochrome P450 1A and 2B activities were observed among the all treatment groups. Male frogs injected with 20 μg/g body weight of estradiol-17β had significantly higher plasma Vg levels than the control group. These results suggest that profiles of plasma Vg and T production in male Xenopus laevis could be useful biomarkers for detecting hormonally active agents. © 2005 Pharmaceutical Society of Japan.

DOI： 10.1248/bpb.28.1748

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掲載種別：研究論文（学術雑誌）  

To evaluate the estrogenic activities of selected estrogenic compounds such as estradiol-17β (E2), nonylphenol (NP), 4-(1-adamantyl)phenol (AdP), bisphenol A (BPA), BPA metabolite 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) and 4,4′-dihydroxy-α-methylstilbene (DHMS) in the shortest possible time, we investigated the expression of estrogen-responsive genes such as vitellogenin I, vitellogenin II and α-type estrogen receptor genes in the liver of male medaka (Oryzias latipes) using reverse transcription- polymerase chain reaction (RT-PCR) techniques. These estrogen-responsive genes responded rapidly to selected estrogenic compounds after 8 h exposure, and the expression of hepatic vitellogenin II and estrogen receptor α mRNA was found to be more responsive than that of vitellogenin I mRNA. As a result, the relative estrogenic potencies of tested chemicals descended in the order of E2 (100) > MBP (0.38) > AdP (0.25) > DHMS (0.05) > NP (0.02) > BPA (0.001). Moreover, this preliminary study indicates that AdP and DHMS should be considered as candidate estrogenic compounds with the potential to induce hepatic estrogen-responsive genes in male medaka. These results suggest that vitellogenin I, vitellogenin II and estrogen receptor α gene expression patterns alter in male medaka treated with selected estrogenic compounds, and that these genes may be useful molecular biomarkers for screening estrogenic endocrine-disrupting chemicals in the shortest possible time. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aquatox.2004.12.011

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掲載種別：研究論文（国際会議プロシーディングス）  

To clarify the effect of environmental endocrine disruptors on the induction of secondary sexual characteristics in wild animals, we observed 1,527 male and 1,847 female specimens of sexually mature Japanese freshwater crabs, Geothelphusa dehaani, collected at 12 sample points from 10 rivers in Sasebo City, Nagasaki Prefecture, Japan. The results obtained were as follows: 1. Abnormal males, with external appearance of a complete male, but having female genital openings, were observed at frequencies of 8-32% of males collected at all sample points. In contrast to this, all females collected were normal. 2. The frequency of abnormal males increased significantly with the increase in individual carapace width. This species inhabits mountain streams in Japan, which are free from tributyltin that is known to induce the sexual mosaic phenomenon in mollusks. The streams are most likely polluted by some agricultural chemicals and chemicals present in waste gases from cars and especially particulate materials from diesel engines. The clear relationship of the frequencies of abnormal males to size (or age) suggests that the sexual mosaic phenomenon is induced not only at early stages of male development but after sexual maturation, in response to long-term exposure to chemical(s) during the whole life cycle of males. The definitive causal factors and mechanisms inducing sexual mosaics in this species are still unclear.

DOI： 10.1093/icb/45.1.39

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掲載種別：研究論文（学術雑誌）  

Phytoestrogens and organochlorine pesticides in the diet of laboratory animals are a possible source of interference in bioassays that assess estrogenic activity. In the present study, we investigated the levels of dietary phytoestrogens, organochlorine pesticides and the estrogenic activity of various diets for an experimental fish and discuss the potential contribution of these substances to estrogenic activity, in comparison with those used in previous studies. After hydrolysis with β-glucuronidase, genistein and daidzein were detected in all of the diets, and there were no significant differences in the contents of these substances among present and previous investigations. In addition, organochlorine pesticides, such as hexachlorobenzene (HCB), β-benzene hexachloride (β-BHC), γ-BHC, trans-nonachlor, and/or endrin, were detected in most fish diets. All of these diets exhibited higher levels of activation of β estrogen receptors than with α estrogen receptors in an in vitro yeast-based bioassay. These results indicate that phytoestrogens, such as genistein and daidzein, were the main substances contributing to the estrogenic activity of the diet. Moreover, some diets may exert estrogenic activity in in vivo tests, indicating the necessity for more careful selection of the feeding diet and measurement of estrogenic substances when performing routine screening assays for endocrine-disrupting chemicals.

DOI： 10.1248/jhs.51.212

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掲載種別：研究論文（学術雑誌）  

Endocrine-disrupting chemicals (EDCs) are giving rise to serious concerns for humans and wildlife. Phytoestrogens, such as daidzein and genistein in plants, and organochlorine pesticides are suspected EDCs, because their chemical structure is similar to that of natural or synthetic estrogens and they have estrogenic activity in vitro and in vivo. We assessed estrogenic activity and dietary phytoestrogen and organochlorine pesticide contents of various fish diets made in the United Kingdom, and compared them with those features of diets made in Japan that were tested in a previous study. Genistein and daidzein were detected in all of the diets. Using an in vitro bioassay, many of these diets had higher activation of estrogen β-receptors than estrogen α-receptors. Organochlorine pesticides such as hexachlorobenzene, β-benzene hexachloride (BHC), and γ-BHC were detected in all fish diets. On the basis of these data, we investigated the effect of differing dietary phytoestrogen content in Japanese fish diets on hepatic vitellogenin production and reproduction (fecundity and fertility) in medaka (Oryzias latipes). Assessment of the effects of a 28-day feeding period on reproduction of paired medaka did not indicate significant differences in the number of eggs produced and fertility among all feeding groups. However, hepatic vitellogenin values were significantly higher for male medaka fed diet C (genistein, 58.5 ± 0.6 μg/g; daidzein, 37.3 ± 0.2 μg/g) for 28 days compared with those fed diet A (genistein, < 0.8 μg/g; daidzein, < 0.8 μg/g) or diet B (genistein, 1.4 ± 0.1 μg/g; daidzein, 2.0 ± 0.1 μg/g). Our findings indicate that fish diets containing high amounts of phytoestrogens, such as diet C, have the potential to induce hepatic vitellogenin production in male medaka, even if reproductive parameters are unaffected. Therefore, some diets, by affecting vitellogenin production in males, may alter estrogenic activity of in vivo tests designed to determine activity of test compounds added to the diet. Copyright 2004 by the American Association for Laboratory Animal Science.

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掲載種別：研究論文（学術雑誌）  

Exposure experiments in medaka and photodecomposition tests were performed using a metabolite of bisphenol A [4-methyl-2,4-bis(p-hydroxyphenyl)-pent-1-ene; MBP], the solubility limit of which is 42 mg/l of water. Three adult medaka were kept in a 21 glass beaker at 25 ± 1°C for 4 days. The LC 50 for 96 hr was > 1000 ppb. The measured average MBP concentration in the breeding water (nominal concentration of 100 ppb) was 49.2 ppb. The average concentration in the whole bodies of medaka after 4 days was 1.92 mg/g-wet body, and the bioconcentration factor (BCF) of MBP was calculated to be 39.0. MBP in water and acetone was decomposed very easily, with about 98% of the MBP being decomposed after several hours under sunlight. MBP was also decomposed after 48 hr of illumination under a white fluorescent lamp.

DOI： 10.1248/jhs.50.576

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記述言語：日本語   出版者・発行元：Japan Society of Material Cycles and Waste Management  

廃棄物は人間活動の増大や物質文明の発展・発達に伴い発生量が増大し, その性状についても多様性を広げている。近年, 一般あるいは産業廃棄物等の埋立処分場からの浸出や漏出水による水質, 底質あるいは土壌汚染や, それらを介した人間の健康あるいは生態系に対する影響が危惧されている。これら環境試料の生物に対する種々の作用 (たとえば, 発ガン性, 変異原性, 内分泌攪乱作用等) を検出するにはバイオアッセイが適していると考えられる。ここでは, 特に内分泌攪乱作用を検出するための遺伝子レベルのバイオアッセイについて概説した。<I>In vitro</I>試験としては, レセプター結合試験, MCF-7細胞などの培養細胞を用いたレポーター遺伝子アッセイ, 酵母ツーハイブリッド法によるホルモン様作用の検出法が有用であると考えられる。それらに加え, 複数の遺伝子群を網羅的に解析するcDNAマイクロアレイ法をヒトや野生生物の毒性あるいは内分泌攪乱性の影響評価に用いることは重要であり, エコトキシコゲノミクスへの応用が期待される。

DOI： 10.3985/wmr.15.240

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00243971082?from=CiNii

担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

Triclosan (2,4,4′-trichloro-2′-hydroxydiphenyl ether) is widely used as antibacterial agent in various industrial products, such as textile goods, soap, shampoo, liquid toothpaste and cosmetics, and often detected in wastewater effluent. In this study, the effects of TCS on the early life stages and reproduction of medaka (Oryzias latipes) were investigated. The 96-h median lethal concentration value of TCS for 24-h-old larvae was 602μg/l. The hatchability and time to hatching in fertilized eggs exposed to 313μg/l TCS for 14 days were significantly decreased and delayed, respectively. An assessment of the effects of a TCS 21-day exposure period on the reproduction of paired medaka showed no significant differences in the number of eggs produced and fertility among the control and 20, 100 and 200μg/l TCS treatment groups. However, concentrations of hepatic vitellogenin were increased significantly in males treated with TCS at 20 and 100μg/l. In the F1 generations, although the hatching of embryos in the 20μg/l treatment showed adverse effects, there was no dose-response relationship between hatchability and TCS treatment levels. These results suggest that TCS has high toxicity on the early life stages of medaka, and that the metabolite of TCS may be a weak estrogenic compound with the potential to induce vitellogenin in male medaka but with no adverse effect on reproductive success and offspring. © 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aquatox.2003.12.005

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

Plasma vitellogenin (VTG) assay was developed using ovariectomized goldfish (Carassius auratus) for determining the estrogenic effects of endocrine-disrupting chemicals. In a laboratory study, we assessed the estrogenic activity of commercial fish diets by using a diet for ornamental carp (CD) and a casein-based formulated fish diet (FD), which was shown to not contain soybean or fish meal in a previous study. In ovariectomized fish, plasma VTG concentrations were significantly higher in the CD-fed group than in the FD-fed group. These results indicate that the estrogen activity of CD may be high enough to cause induction of plasma VTG in ovariectomized goldfish as previously observed in male goldfish. Moreover, the effect of estrogen on plasma VTG induction was confirmed by significant plasma VTG production following the exposure of FD-fed ovariectomized goldfish to a nominal estradiol-17β concentration of 100 μg/l for 31 days. Our data suggest that induction of plasma VTG using ovariectomized goldfish is a good tool for evaluating the estrogenic effects of endocrine-disrupting chemicals.

DOI： 10.1248/jhs.50.169

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掲載種別：研究論文（学術雑誌）  

The acute toxicity of endocrine disrupters in two crustaceans, Americamysis bahia (A. bahia) and Daphnia magna (D. magna), was investigated and the toxicological responses compared. Bisphenol A had the lowest toxicity to D. magna, the 48 hr median lethal concentrations (LC50) values was 12.8 mg/l. However, the toxic sensitivity of A. bahia to bisphenol A was approximately 10-fold higher than for D. magna (48 hr LC50; 1.34 mg/l). The 48 hr LC50 of estradiol-17β was 2.97 and 1.69 mg/l in D. magna and A. bahia, respectively. Nonylphenol had the highest lethal toxicity against both A. bahia (48 hr LC50; 0.051 mg/l) and D. magna (48 hr LC50; 0.18 mg/l). However, ecdysteroids, and ecdysteroidal activity insecticides, such as tebufenozide, and juvenile hormone analog, had no toxic effects against either A. bahia or D. magna at the concentrations tested in this study. These results suggest that A. bahia is a more suitable toxicity test organism for endocrine disrupters than D. magna because of the higher sensitivity of A. bahia to the toxicological effect.

DOI： 10.1248/jhs.50.97

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

The effects of nonylphenol (NP) on plasma vitellogenin (VTG) and steroid hormone values, as well as hepatic cytochrome P450 1A (CYP1A) and glutathione-S-transferase (GST) activities, were measured in goldfish (Carassius auratus) fed a diet with a low (formulated diet, FD) or high (commercial diet, CD) content of phytoestrogens, including genistein and daidzein. Male goldfish with secondary sexual characteristics were exposed to nominal NP concentrations of 0.1, 1.0, 10, and 100 μg/L in the water for 28 days while being fed either the FD or CD diet at 1.0% of body weight daily. Plasma VTG concentration in male goldfish exposed to 100 μg of NP/L and fed FD was significantly higher than that in the FD-fed control fish at seven, 21, and 28 days. However, fish of the CD-fed group exposed to 100 μg of NP/L had significantly higher plasma VTG concentration than did fish of the CD-fed control group at 28 days only. Moreover, plasma VTG concentration in fish of the CD-fed control group was about 100-fold higher than that in fish of the FD-fed control group. Although the estrogenic effects of a phytoestrogen-enriched diet caused a decrease in testosterone and/or 11-ketotestosterone values in the CD-fed fish, there was no dose-response relationship between androgen and amount of NP to which the FD-fed fish were exposed. Nonylphenol does not have appreciable effects on hepatic CYP1A and GST activities in male goldfish at concentrations as low as 100 μg/L. These results suggest that NP has estrogenic activity in male goldfish at the nominal concentration of 100 μg/L, and that phytoestrogens, such as genistein and daidzein, in the CD inhibit an aspect(s) of steroid release and/or synthesis common to testosterone and 11-ketotestosterone. However, results of in vivo screening assays for endocrine-disrupting chemicals may be seriously affected by phytoestrogens in the diet, depending on content or potency of estrogenic activity; therefore, we recommend use in research of a standardized, open-formula diet in which estrogenic substances have been reduced to amounts that do not alter the results of studies that are influenced by exogenous estrogens.

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掲載種別：研究論文（学術雑誌）  

Triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) is widely used as an antibacterial agent in various industrial products, such as textile goods, soap, shampoo, liquid toothpaste and cosmetics, and often detected in wastewater effluent. However, there is a paucity of data on the toxicity of triclosan and its effects on aquatic organisms. In this study, the acute toxicity of triclosan to the Microtox bacterium (Vibrio fischeri), a microalga (Selenastrum capricornutum), a crustacean (Ceriodaphnia dubia) and fish (Danio rerio and Oryzias latipes) was examined. As a result, the MicrotoxR bacterium, crustacean and fish had similar sensitivities towards triclosan toxicity (i.e., IC25 from 0.07 to 0.29 mg/L triclosan). In contrast, the microalga was about 30-80-fold (IC25 = 0.0034 mg/L triclosan) more sensitive to triclosan toxicity than the bacterium and fish. Therefore, triclosan is quite highly toxic to aquatic animals, and is particularly highly toxic to the green alga used as a test organism in this study. This result indicates that triclosan exerts a marked influence on algae, which are important organisms being the first-step producers in the ecosystem; therefore, the possible destruction of the balance of the ecosystem is expected if triclosan is discharged into the environment at high levels.

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掲載種別：研究論文（学術雑誌）  

A 14-day partial life-cycle test was performed to assess the effects of 17beta-estradiol (E2) on the survival, growth, sexual development and molting cycles of a marine crustacean mysid shrimp (Americamysis bahia). Seven-day-old mysids were exposed to the nominal E2 concentrations of 31.3, 62.5, 125, 250 and 500 microg/l for 14 days. The total length and the body weight of mysids significantly decreased relative to the controls when exposed to 62.5, 250 and 500 microg/l E2 for 14 days. Moreover, the carapace length significantly decreased in the 500 microg/l E2 treatment groups. No significant differences were observed in sex ratio with the appearance of secondary sex characteristics in the all treatment groups including the control and solvent control groups. However, the percentage of females with eggs in the oviduct or brood sac decreased significantly in mysids treated with E2 at 62.5, 125, 250 and 500 microg/l. The cumulative total number of molting cycles when exposed to E2 for 14 days significantly decreased in the treatment groups at 500 microg/l relative to the controls. These results suggest that concentrations of E2 over 62.5 microg/l may cause growth suppression in mysid shrimp, and that the disruption of molting cycles may result in alterations in growth due to a sublethal response to toxicant exposure.

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掲載種別：研究論文（学術雑誌）  

Phytoestrogens, such as daidzein and genistein in plants are suspected as endocrine-disrupting chemicals (EDCs), because their chemical structures are similar to natural or synthetic estrogens, and have estrogenic activity in vitro and in vivo. An EDC study was carried out on the diets of various animals in vivo. However, many of these diets include phytoestrogens and may already possess estrogenic activity. In this study, we evaluated the estrogenic activity of phytoestrogens (such as daidzin, genistin, daidzein, genistein, coumestrol and equol) and the feed diets for experimental animals, such as fish, amphibians and reptiles, towards human estrogen receptors α (hER-α) and β (hER-β), and the genistein and daidzein content in these diets from HPLC analysis. Coumestrol showed the highest estrogenic activity for hER-α and -β in the -S9 test. Equol showed the highest estrogenic activity for hER-α in the +S9 test. The estrogenic activities of coumestrol, equol and genistein were approximately one hundred to two thousand times higher than that of daidzein. Many of these compounds showed higher compatibility with hER-β than with hER-α. A diet for fish from soybean was indicated to contain the highest amounts of genistein and daidzein. Moreover, this fish diet had the highest estrogenic activity for hER-α and -β. The estrogenic activity was found with hydrolysis by β-glucuronidase, showing higher compatibility with hER-β than with hER-α. In addition, correlation between the contents of genistein and estrogenic activities in the diets was found, with the exception of part of the diet. Therefore, this indicates that the genistein content contributes to the estrogenic activity of the diets. These results suggest that in vivo estrogenic activity might be caused by the diet provided to an experimental animal, indicating the necessity for more careful selection of the feeding diet and measurement of estrogenic substances when performing an in vivo screening assay for EDCs.

DOI： 10.1248/jhs.49.481

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掲載種別：研究論文（学術雑誌）  

Previously, we reported that the induction of vitellogenin mRNA in the larvae of Caenorhabditis elegans (C. elegans) can be used as a biomarker for short-term screening of environmental endocrine disrupters. Therefore, the present study was designed to determine if the induction of metallothionein (MT) mRNA in the larvae of C. elegans would be a biomarker for short-term screening of heavy metals. The larvae were exposed to various concentrations of cadmium (Cd), mercury (Hg), zinc chloride (Zn), cupper chloride (Cu) or lead acetate (Pb) for 3 h. Cd (1, 10 and 100 μM) and Hg (0.01, 0.1, 1 and 10 μM) exposures resulted in the marked induction of MT-I and MT-II mRNAs in the larvae of C. elegans as measured by reverse transcription polymerase chain reaction. The Cd-and Hg induction of MT-II mRNA was higher than that of MT-I mRNA, and concentration-dependent increase was observed in MT-II but not in MT-I. Time course analyses for MT-I and MT-II mRNA expressions with Cd and Hg were also determined. Cd induction of MT-I and MT-II mRNAs reached a peak at 2 h after the exposure (10 μM), and the levels of MT-II were higher than that of MT-I. For Hg, an initial peak of induction of MT-II mRNA occurred 15 min after the exposure (0.1 μM), and the levels reached maximum by 2 h. The initial peak of induction of MT-I mRNA occurred much later (∼ 2 h after Hg exposure) than MT-II mRNA. These results indicated that the induction of MT-II mRNA in the larvae of C. elegans can be used as a potential biomarker for short-term exposure to Cd and Hg.

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掲載種別：研究論文（学術雑誌）  

Three monomers (Bis-GMA, UDMA, and TEGDMA) and five polymerization initiators (CQ, BPO, DMPT, DMAEMA, and ATU) commonly used in dental composite resins were tested for estrogenic activity using a reporter gene assay (yeast two-hybrid system) in vitro, and compared with bisphenol-A (BPA). Estrogenic activity was indicated by agonist and antagonist activity, with (+S9) and without (-S9) metabolic activation using rat liver cells. No estrogenic agonist activity was seen for each monomer and polymerization initiator in either the -S9 and +S9 tests in the concentration ranges examined in this study. On the other hand, estrogen antagonist activity was found with BPO and DMPT. BPO showed antagonist activity at a concentration of ∼ 1800 nM with the -S9 test, but not with the +S9 test. With DMPT, antagonist activity was not seen with the -S9 test, but it was seen at a concentration of ∼ 610 nM using the +S9 test. With BPA, the +S9 test indicated antagonist activity at a concentration of ∼ 780 nM. The estrogen antagonist activities of DMPT and BPA appeared to be similar. CQ, DMAEMA, ATU, and the three monomers did not show antagonist activity as demonstrated by the -S9 or +S9 tests within the concentration range tested in this study. © 2003 Kluwer Academic Publishers.

DOI： 10.1023/A:1022923713892

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担当区分：筆頭著者  

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

In this study, we analyzed contents of phytoestrogens (genistein, daidzein, equol, and coumestrol) in two commercial fish diets [a diet for trout (TD) and a diet for ornamental carp (CD)] using Liquid Chromatography-Mass Spectroscopy/Mass Spectroscopy (LC-MS/MS), and these contents were compared with that of a casein-based formulated fish diet (FD) which does not contain soya bean or fish meal. We also analyzed phytoestrogen contents in commercial infant casein- and soya bean-based diets. The contents of phytoestorogens were generally high in CD, TD, and soya milk, and low or non-detectable in FD and casein-based milks. Among these samples, CD showed the highest phytoestrogen contents: genistein, 390800 ng/g; daidzein, 416800 ng/g; coumestrol, 1325 ng/g; equol, 6.4 ng/g. We also determined the estrogenic activity of the fish diets using male goldfish by measuring plasma vitellogenin (VTG) levels as a biomarker of estrogen exposure. When male goldfish were fed one of these diets for 31 days, plasma VTG was detected in CD-fed fish (78.01 ± 48.18 μg/ml) and TD-fed fish (3.51 ± 3.83 μg/ml), whereas plasma VTG was not detected in FD-fed fish (less than 0.040 μg/ml). These results indicate that the commercial fish diets examined contain a large amount of phytoestrogens and showed estrogenic activity that were strong enough to induce VTG production in male goldfish. It is necessary to eliminate estrogenic substances other than test chemicals in the screening test system for estrogenic endocrine-disrupting chemicals (EDCs). Since the formulated diet developed in the present study contain less phytoestrogens than the commercial fish diets and has low estrogenic activity, it is suggested that VTG production using male goldfish in combination with the low estrogen fish diet is a good in vivo system for evaluation of estrogenic effects of EDCs.

DOI： 10.1248/jhs.48.427

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担当区分：筆頭著者   記述言語：日本語   出版者・発行元：環境技術学会  

DOI： 10.5956/jriet.31.604

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担当区分：筆頭著者  

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

Vitellogenin (VTG) is believed to be an effective and sensitive biomarker to detect the effects of endocrine-disrupting chemicals (EDCs) on fish. An enzyme-linked immunosorbent assay (ELISA) was developed in this study for the quantification of VTG in goldfish (Carassius auratus) blood plasma using a monoclonal antibody against carp lipovitellin which is known to cross-react with goldfish VTG, and a working range of 7.8 to 500 ng VTG/ml was established. A laboratory study involving the dosing of male goldfish for 28 days with a range of bisphenol-A (BPA) concentrations was conducted, and the established ELISA was used. There was no significant induction of VTG at the concentrations of 1 and 10 μg/l. Exposure to 100 μg/l and 1000 μg/l BPA for 28 days significantly elevated plasma VTG concentrations to 201 ± 90 μg/ml and 104552 ± 24920 μg/ml, respectively. To confirm the effect of temperature on VTG induction, male goldfish were exposed to the nominal concentration of 17β-estradiol (E2) 100 μg/l at 10° and 30°C for 10 days. Plasma VTG concentration in male goldfish increased more quickly in the fish exposed at 30°C than in those at 10°C. In addition, the plasma VTG concentration in the 30°C group (10463 ± 3268 μg/ml) was higher than that of the 10°C group (1.42 ± 1.6 μg/ml) after 1 day of exposure. Thus goldfish are useful for the investigation of EDCs under various conditions since they are relatively small in size, and the ELISA established in the present study will contribute to various types of research.

DOI： 10.1248/jhs.47.213

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記述言語：日本語   出版者・発行元：環境ホルモン学会(日本内分泌撹乱化学物質学会)  

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記述言語：日本語   出版者・発行元：日本毒性学会  

【目的】更年期障害のホルモン補充用医薬品プレマリンは、牝馬の尿中に存在するエクイリン(Eq)などエクインエストロゲン類(EQs)を成分とする。これまでに我々は北海道の河川から複数のEQsを初めて検出し、存在実態を明らかにした。本研究では、魚類に対するEqの有害性とそのメカニズムを明らかにするため、雌雄ヒメダカ(&lt;i&gt;Oryzias latipes&lt;/i&gt;)の繁殖及び次世代に対する影響を評価し、肝臓中の遺伝子発現解析を行った。&lt;br&gt;【方法】成熟雌雄ペア（5ペア/濃度区）を助剤対照区、Eq-10, 100及び1000 ng/Lに21日間曝露した。曝露期間中、各ペアの産卵数、受精率及び生死と産卵後のF&lt;sub&gt;1&lt;/sub&gt;胚の孵化率を算出した。曝露後は全長、体重、肝臓(HSI)及び生殖腺対指数(GSI)を算出した。遺伝子発現解析は、肝臓中&lt;i&gt;vitellogenin&lt;/i&gt;s (&lt;i&gt;Vtg1&lt;/i&gt;, &lt;i&gt;2&lt;/i&gt;)、&lt;i&gt;choriogenin&lt;/i&gt;s (&lt;i&gt;ChgL&lt;/i&gt;, &lt;i&gt;H&lt;/i&gt;)、&lt;i&gt;estrogen receptor&lt;/i&gt;s (&lt;i&gt;ERα&lt;/i&gt;, &lt;i&gt;β1&lt;/i&gt;, &lt;i&gt;β2&lt;/i&gt;)、&lt;i&gt;pregnane X receptor&lt;/i&gt; (&lt;i&gt;PXR&lt;/i&gt;)、&lt;i&gt;cytochrome P4501A&lt;/i&gt;及び&lt;i&gt;3A&lt;/i&gt; (&lt;i&gt;CYP1A&lt;/i&gt;, &lt;i&gt;3A&lt;/i&gt;)と内部標準遺伝子をリアルタイムPCRで相対定量した。&lt;br&gt;【結果及び考察】繁殖試験の結果、雌雄の全長、体重、HSI及びGSIに変化はみられなかったが、1000 ng/L区における21日間の平均産卵数は有意に減少した。また、F&lt;sub&gt;1&lt;/sub&gt;胚の孵化率は100及び1000 ng/L区で有意に減少し、1000 ng/L区の孵化仔魚では背骨の湾曲など奇形が観察された。遺伝子発現解析の結果、雄では&lt;i&gt;Vtg&lt;/i&gt;s、&lt;i&gt;Chg&lt;/i&gt;s、&lt;i&gt;ERα&lt;/i&gt;/&lt;i&gt;β1&lt;/i&gt;及び&lt;i&gt;PXR&lt;/i&gt;遺伝子の濃度依存的な発現誘導がみられたが、雌では測定対象とした遺伝子の発現に変化はなかった。これらのことから、Eqはヒメダカの繁殖及び次世代に影響し（最小作用濃度100 ng/L）、肝臓中の遺伝子発現応答の性差が示唆された。&lt;br&gt;【謝辞】本研究は、環境省「EXTEND2010基盤的研究」の助成を受けて実施した。

J-GLOBAL

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記述言語：日本語   出版者・発行元：(一社)日本毒性学会  

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記述言語：日本語   出版者・発行元：尚絅学園  

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記述言語：日本語   出版者・発行元：(一社)日本毒性学会  

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J-GLOBAL

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記述言語：日本語   出版者・発行元：環境技術学会  

DOI： 10.5956/jriet.32.244

CiNii Books

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記述言語：日本語   出版者・発行元：廃棄物学会  

CiNii Books

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J-GLOBAL

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J-GLOBAL

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記述言語：日本語   出版者・発行元：環境コミュニケーションズ  

CiNii Books

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記述言語：日本語   出版者・発行元：長崎大学  

CiNii Books

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