LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 351

Search options

  1. Article ; Online: MITOTIC ACTIVITY OF VAGINAL EPITHELIAL CELLS FOLLOWING NEONATAL INJECTIONS OF DIFFERENT DOSES OF ESTROGEN IN MICE.

    Iguchi, Taisen / Ohta, Yasuhiko / Takasugi, Noboru

    Development, growth & differentiation

    2023  Volume 18, Issue 1, Page(s) 69–78

    Abstract: In C57Black/Tw mice given injections of 1 μg estradiol-17β (E) for 5 days beginning on the day of birth, and killed a few days after the treatment, the vaginal epithelium showed estrogen-dependent proliferation and parakeratosis. In contrast, in the mice ...

    Abstract In C57Black/Tw mice given injections of 1 μg estradiol-17β (E) for 5 days beginning on the day of birth, and killed a few days after the treatment, the vaginal epithelium showed estrogen-dependent proliferation and parakeratosis. In contrast, in the mice treated neonatally with 30 μg E for 5 days, the vaginal epithelium exhibited estrogen-independent proliferation and cornification or parakeratosis. Two peaks occurred in the mitotic rate in vaginal epithelial cells in the proximal and middle vaginae of the 1 μgE-treated mice, at 1 and 5 days of age, respectively, while the first peak was lacking in the distal vagina. The mitotic activity in 1 μgE-treated mice declined to the control level at 60 days. In the 30 μgE-treated animals also, 2 peaks were found in the mitotic rate at 1 and 7 days in both the proximal and middle vaginae. In contrast to the 1 μgE-treated mice, although the rate dropped once at 10 days, it increased again at 20 days and remained high thereafter. The second peak at 7 days of age coincided with the active proliferation of nodules appearing in the 30 μgE-treated mice. In the distal vagina, a peak occurred in the mitotic rate at 7 days without a preceding peak like that observed in the other parts of the vagina following the first injection of E on the day of birth.
    Language English
    Publishing date 2023-06-06
    Publishing country Japan
    Document type Journal Article
    ZDB-ID 280433-5
    ISSN 1440-169X ; 0012-1592
    ISSN (online) 1440-169X
    ISSN 0012-1592
    DOI 10.1111/j.1440-169X.1976.00069.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: The ter mutation first causes primordial germ cell deficiency in ter/ter mouse embryos at 8 days of gestation.

    Sakurai, Takayuki / Iguchi, Taisen / Moriwaki, Kazuo / Noguchi, Motoko

    Development, growth & differentiation

    2023  Volume 37, Issue 3, Page(s) 293–302

    Abstract: The ter (teratoma) mutation causes primordial germ cell (PGC) deficiency in ter/ter embryos at 9.5-12.5 days of post-coitum (dpc) in mouse strains 129/Sv-ter and LTXBJ-ter. To study the effects of the ter mutation on the PGC development more precisely, ... ...

    Abstract The ter (teratoma) mutation causes primordial germ cell (PGC) deficiency in ter/ter embryos at 9.5-12.5 days of post-coitum (dpc) in mouse strains 129/Sv-ter and LTXBJ-ter. To study the effects of the ter mutation on the PGC development more precisely, we examined the PGC number and distribution in 7.5-12.5 dpc embryo of ter congenic C57BL/6J-ter strain using their complete serial sections. The ter genotypes of embryos were identified by the polymerase chain reaction (PCR) polymorphisms of the microsatellite DNA of the Grl-1 locus mapped near the ter locus. Results showed that: (i) the PGC number in ter/ter embryos was similar to those of + /ter and + / + embryos at 7.5 dpc, and did not increase at 8.0-12.5 dpc, although those of normal littermates did usually; (ii) the PGC migration to genital ridges was never affected in all embryos; and (iii) the ter genotype difference in the PGC numbers was not recognized between + /ter and + / + embryos. We concluded that the ter mutation does not affect the PGC appearance around 7.5 dpc, but first causes PGC deficiency around 8.0 dpc at the beginning of their migration and proliferation, suggesting that the normal function of the ter gene may be essential for the proliferation or survival mechanisms of PGC.
    Language English
    Publishing date 2023-06-06
    Publishing country Japan
    Document type Journal Article
    ZDB-ID 280433-5
    ISSN 1440-169X ; 0012-1592
    ISSN (online) 1440-169X
    ISSN 0012-1592
    DOI 10.1046/j.1440-169X.1995.t01-2-00007.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article: Iopanoic acid alters thyroid hormone-related gene expression, thyroid hormone levels, swim bladder inflation, and swimming performance in Japanese medaka.

    Horie, Yoshifumi / Sawada, Ayaka / Dorcas, Uaciquete / Ramaswamy, Babu Rajendran / Iguchi, Taisen

    Comparative biochemistry and physiology. Toxicology & pharmacology : CBP

    2024  Volume 281, Page(s) 109930

    Abstract: Disruption of the thyroid hormone system by synthetic chemicals is gaining attention owing to its potential negative effects on organisms. In this study, the effects of the dio-inhibitor iopanoic acid (IOP) on the levels of thyroid hormone and related ... ...

    Abstract Disruption of the thyroid hormone system by synthetic chemicals is gaining attention owing to its potential negative effects on organisms. In this study, the effects of the dio-inhibitor iopanoic acid (IOP) on the levels of thyroid hormone and related gene expression, swim bladder inflation, and swimming performance were investigated in Japanese medaka. Iopanoic acid exposure suppressed thyroid-stimulating hormone β (tshβ), tshβ-like, iodotyronin deiodinase 1 (dio1), and dio2 expression, and increased T4 and T3 levels. In addition, IOP exposure inhibited swim bladder inflation, reducing swimming performance. Although adverse outcome pathways of thyroid hormone disruption have been developed using zebrafish, no adverse outcome pathways have been developed using Japanese medaka. This study confirmed that IOP inhibits dio expression (a molecular initiating event), affects T3 and T4 levels (a key event), and reduces swim bladder inflation (a key event) and swimming performance (an adverse outcome) in Japanese medaka.
    Language English
    Publishing date 2024-04-23
    Publishing country United States
    Document type Journal Article
    ZDB-ID 189285-x
    ISSN 1532-0456 ; 0306-4492 ; 0742-8413
    ISSN 1532-0456 ; 0306-4492 ; 0742-8413
    DOI 10.1016/j.cbpc.2024.109930
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Laterally biased diffusion of males of the water flea Daphnia magna.

    Toyota, Kenji / Yasugi, Masaki / Tatarazako, Norihisa / Iguchi, Taisen / Watanabe, Eiji

    Journal of experimental zoology. Part A, Ecological and integrative physiology

    2022  Volume 337, Issue 6, Page(s) 626–638

    Abstract: The water flea, Daphnia magna, is a representative zooplankton that lives in freshwater environments. It primarily propagates via asexual reproduction in normal and healthy environmental conditions. Unsuitable environmental conditions induce D. magna to ... ...

    Abstract The water flea, Daphnia magna, is a representative zooplankton that lives in freshwater environments. It primarily propagates via asexual reproduction in normal and healthy environmental conditions. Unsuitable environmental conditions induce D. magna to change its mode of reproduction from asexual to sexual reproduction. During sexual reproduction, D. magna produces special tough eggs (resting eggs) that can survive severe environmental conditions. Despite an increase in our understanding of their mating behavior, the sex-specific characteristics of swimming behavior among daphnid species are poorly understood. In this study, we analysed the swimming patterns and dynamics of female and male adult D. magna using computer modeling. Males displayed laterally biased diffusion in contrast to the homogeneous, nondirectional diffusion of females. Computer modeling analysis using a discrete-time Markov chain simulation, in which the frequencies of turning behavior were evaluated as probability distributions, explained the greater diffusion of males in the horizontal direction. We presumed that high diffusion in the horizontal direction would increase the probability of encountering a distant mate. Our findings suggest that male D. magna increases genotypic heterogeneity by effectively selecting certain motion parameters.
    MeSH term(s) Animals ; Cladocera ; Daphnia ; Female ; Male ; Reproduction
    Language English
    Publishing date 2022-04-13
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1474896-4
    ISSN 2471-5646 ; 1932-5223 ; 2471-5646 ; 1932-5231 ; 1552-499X
    ISSN (online) 2471-5646 ; 1932-5223
    ISSN 2471-5646 ; 1932-5231 ; 1552-499X
    DOI 10.1002/jez.2595
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Gonadal Soma-Derived Factor Expression is a Potential Biomarker for Predicting the Effects of Endocrine-Disrupting Chemicals on Gonadal Differentiation in Japanese Medaka (Oryzias Latipes).

    Horie, Yoshifumi / Kanazawa, Nobuhiro / Takahashi, Chiho / Tatarazako, Norihisa / Iguchi, Taisen

    Environmental toxicology and chemistry

    2022  Volume 41, Issue 8, Page(s) 1875–1884

    Abstract: Chemicals with androgenic or estrogenic activity induce the sex reversal and/or intersex condition in various teleost fish species. Previously, we reported that exposure to 17α-methyltestosterone, bisphenol A, or 4-nonylphenol induces changes in ... ...

    Abstract Chemicals with androgenic or estrogenic activity induce the sex reversal and/or intersex condition in various teleost fish species. Previously, we reported that exposure to 17α-methyltestosterone, bisphenol A, or 4-nonylphenol induces changes in expression of the gonadal soma-derived factor (gsdf) gene accompanied by disruption of gonadal differentiation in Japanese medaka (Oryzias latipes). These findings suggest that gsdf expression might be a useful biomarker for predicting the potential effect of chemicals on gonadal differentiation. We examined the gsdf expression in Japanese medaka exposed to chemicals with estrogenic or androgenic activity. Exposure to the androgenic steroid 17β-trenbolone at 0.5-22.1 μg/L induced the development of ovotestis (presence of ovarian tissue with testicular tissue) and female-to-male sex reversal in XX embryos, and exposure at 6.32 and 22.1 μg/L significantly increased gsdf expression in XX embryos compared with controls at developmental stage 38 (1 day before hatching). In the present study, no statistically significant difference in gsdf mRNA expression was observed after exposure to 17β-estradiol, 17α-ethinylestradiol, and 4-t-octylphenol, which have estrogenic activity. In addition, antiandrogenic chemicals or chemicals without endocrine-disrupting activity did not induce changes in gsdf expression in XX or XY embryos. Thus, an increase in gsdf expression after androgen exposure was observed in XX embryos. Together, these findings indicate that gsdf expression might be useful for predicting the adverse effect of chemicals on gonadal differentiation. Environ Toxicol Chem 2022;41:1875-1884. © 2022 SETAC.
    MeSH term(s) Animals ; Biomarkers/metabolism ; Endocrine Disruptors/metabolism ; Ethinyl Estradiol/metabolism ; Female ; Gonads ; Male ; Oryzias/metabolism
    Chemical Substances Biomarkers ; Endocrine Disruptors ; Ethinyl Estradiol (423D2T571U)
    Language English
    Publishing date 2022-06-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 46234-2
    ISSN 1552-8618 ; 0730-7268
    ISSN (online) 1552-8618
    ISSN 0730-7268
    DOI 10.1002/etc.5353
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article: Gene Duplication of Androgen Receptor As An Evolutionary Driving Force Underlying the Diversity of Sexual Characteristics in Teleost Fishes.

    Ryu, Tsukasa / Okamoto, Keigo / Ansai, Satoshi / Nakao, Miki / Kumar, Anu / Iguchi, Taisen / Ogino, Yukiko

    Zoological science

    2023  Volume 41, Issue 1, Page(s) 68–76

    Abstract: Sexual dimorphism allows species to meet their fitness optima based on the physiological availability of each sex. Although intralocus sexual conflict appears to be a genetic constraint for the evolution of sex-specific traits, sex-linked genes and the ... ...

    Abstract Sexual dimorphism allows species to meet their fitness optima based on the physiological availability of each sex. Although intralocus sexual conflict appears to be a genetic constraint for the evolution of sex-specific traits, sex-linked genes and the regulation of sex steroid hormones contribute to resolving this conflict by allowing sex-specific developments. Androgens and their receptor, androgen receptor (Ar), regulate male-biased phenotypes. In teleost fish,
    MeSH term(s) Male ; Animals ; Female ; Receptors, Androgen/genetics ; Gene Duplication ; Sex Characteristics ; Reproduction ; Fishes/genetics
    Chemical Substances Receptors, Androgen
    Language English
    Publishing date 2023-04-12
    Publishing country Japan
    Document type Review ; Journal Article
    ZDB-ID 2038883-4
    ISSN 2212-3830 ; 0289-0003
    ISSN (online) 2212-3830
    ISSN 0289-0003
    DOI 10.2108/zs230098
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article: Preself-Feeding Medaka Fry Provides a Suitable Screening System for in Vivo Assessment of Thyroid Hormone-Disrupting Potential

    Myosho, Taijun / Ishibashi, Ayaka / Fujimoto, Shingo / Miyagawa, Shinichi / Iguchi, Taisen / Kobayashi, Tohru

    Environmental science & technology. 2022 Apr. 27, v. 56, no. 10

    2022  

    Abstract: Endocrine-disrupting chemicals are assessed based on their physiological potential and their potential associated adverse effects. However, suitable end points for detection of chemicals that interfere with the thyroid hormone (TH) system have not been ... ...

    Abstract Endocrine-disrupting chemicals are assessed based on their physiological potential and their potential associated adverse effects. However, suitable end points for detection of chemicals that interfere with the thyroid hormone (TH) system have not been established in nonmammals, with the exception of amphibian metamorphosis. The aims of the current study were to develop an in vivo screening system using preself-feeding medaka fry (Oryzias latipes) for the detection of TH-disrupting chemicals and elucidate the underlying molecular mechanism. 17α-Ethinylestradiol (EE2: <100 ng/L) did not induce mRNA expression of estrogen-responsive genes, vitellogenins (vtgs) mRNA. Meanwhile, coexposure with thyroxin (T4) induced an increase of vtg expression. TH-disrupting chemicals (thiourea (TU), perfluorooctanoic acid (PFOA), and tetrabromobisphenol A (TBBPA)) significantly suppressed EE2 (1,000 ng/L)-induced vtg1 expression, while T4 rescued their expression as well as that of thyroid hormone receptor α (tRα) and estrogen receptors (esrs). These results were supported by in silico analysis of the 5′-transcriptional regulatory region of these genes. Furthermore, the esr1 null mutant revealed that EE2-induced vtg1 expression requires mainly esr2a and esr2b in a TH-dependent manner in preself-feeding fry. Application of preself-feeding medaka fry as a screening system might help decipher the in vivo mechanisms of action of TH-disrupting molecules, while providing an alternative to the traditional animal model.
    Keywords Oryzias latipes ; amphibians ; animal models ; computer simulation ; environmental science ; estrogens ; gene expression ; metamorphosis ; mutants ; perfluorooctanoic acid ; thiourea ; thyroid hormone receptors ; thyroid hormones ; thyroxine ; vitellogenin
    Language English
    Dates of publication 2022-0427
    Size p. 6479-6490.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5851
    DOI 10.1021/acs.est.1c06729
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  8. Article: Gonadal Soma‐Derived Factor Expression is a Potential Biomarker for Predicting the Effects of Endocrine‐Disrupting Chemicals on Gonadal Differentiation in Japanese Medaka (Oryzias Latipes)

    Horie, Yoshifumi / Kanazawa, Nobuhiro / Takahashi, Chiho / Tatarazako, Norihisa / Iguchi, Taisen

    Environmental toxicology and chemistry. 2022 Aug., v. 41, no. 8

    2022  

    Abstract: Chemicals with androgenic or estrogenic activity induce the sex reversal and/or intersex condition in various teleost fish species. Previously, we reported that exposure to 17α‐methyltestosterone, bisphenol A, or 4‐nonylphenol induces changes in ... ...

    Abstract Chemicals with androgenic or estrogenic activity induce the sex reversal and/or intersex condition in various teleost fish species. Previously, we reported that exposure to 17α‐methyltestosterone, bisphenol A, or 4‐nonylphenol induces changes in expression of the gonadal soma‐derived factor (gsdf) gene accompanied by disruption of gonadal differentiation in Japanese medaka (Oryzias latipes). These findings suggest that gsdf expression might be a useful biomarker for predicting the potential effect of chemicals on gonadal differentiation. We examined the gsdf expression in Japanese medaka exposed to chemicals with estrogenic or androgenic activity. Exposure to the androgenic steroid 17β‐trenbolone at 0.5–22.1 μg/L induced the development of ovotestis (presence of ovarian tissue with testicular tissue) and female‐to‐male sex reversal in XX embryos, and exposure at 6.32 and 22.1 μg/L significantly increased gsdf expression in XX embryos compared with controls at developmental stage 38 (1 day before hatching). In the present study, no statistically significant difference in gsdf mRNA expression was observed after exposure to 17β‐estradiol, 17α‐ethinylestradiol, and 4‐t‐octylphenol, which have estrogenic activity. In addition, antiandrogenic chemicals or chemicals without endocrine‐disrupting activity did not induce changes in gsdf expression in XX or XY embryos. Thus, an increase in gsdf expression after androgen exposure was observed in XX embryos. Together, these findings indicate that gsdf expression might be useful for predicting the adverse effect of chemicals on gonadal differentiation. Environ Toxicol Chem 2022;41:1875–1884. © 2022 SETAC
    Keywords Oryzias latipes ; adverse effects ; androgens ; biomarkers ; bisphenol A ; chemistry ; ecotoxicology ; estrogenic properties ; fish ; gene expression ; genes ; sex reversal ; testes
    Language English
    Dates of publication 2022-08
    Size p. 1875-1884.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 46234-2
    ISSN 1552-8618 ; 0730-7268
    ISSN (online) 1552-8618
    ISSN 0730-7268
    DOI 10.1002/etc.5353
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  9. Article ; Online: Methyl farnesoate regulatory mechanisms underlying photoperiod-dependent sex determination in the freshwater crustacean Daphnia magna.

    Toyota, Kenji / Sato, Tomomi / Iguchi, Taisen / Ohira, Tsuyoshi

    Journal of applied toxicology : JAT

    2020  Volume 41, Issue 2, Page(s) 216–223

    Abstract: Freshwater zooplankton Daphnia magna has been widely used in ecotoxicology studies. During the last 20 years, it has been demonstrated that the topical application of juvenile hormone (JH) or JH analogs to mother daphnids induce male offspring production. ...

    Abstract Freshwater zooplankton Daphnia magna has been widely used in ecotoxicology studies. During the last 20 years, it has been demonstrated that the topical application of juvenile hormone (JH) or JH analogs to mother daphnids induce male offspring production. Based on this finding, an in vivo screening validation method for chemicals with JH agonistic effect has developed. Although this screening system successfully identified a number of JH-like chemicals, molecular mechanisms underlying the male sex-determining process remain largely unknown. To address this issue, we established a reliable male- or female-producing system using Daphnia pulex WTN6 strain by changing the rearing photoperiod. Taking advantage of this rearing system, we successfully found several factors involving male sex determination such as ionotropic glutamate receptors, protein kinase C and pantothenate. Here, we used two D. magna strains that can also control the production of female or male offspring by photoperiod differences as model species for ecotoxicology studies. We demonstrated that either treatment of antagonist of ionotropic glutamate receptors or inhibitor of protein kinase C strongly suppressed male offspring production even under male-producing conditions. Moreover, we revealed that male sex-determining processes are likely diverged between D. magna and D. pulex based on the current experiment. This study provides a fine experimental method for in vivo screening not only JH agonists but also JH antagonists. Moreover, using daphnids with photoperiod-dependent sex determination manner will hugely contribute to understanding the mode-of-action of JH in daphnids.
    MeSH term(s) Animals ; Daphnia/drug effects ; Daphnia/genetics ; Daphnia/growth & development ; Denmark ; Ecotoxicology/methods ; Fatty Acids, Unsaturated/toxicity ; Female ; Freshwater Biology ; Genetic Variation ; Genotype ; Male ; Photoperiod ; Reproduction/drug effects ; Sex Determination Processes/drug effects ; Sex Differentiation/drug effects
    Chemical Substances Fatty Acids, Unsaturated
    Language English
    Publishing date 2020-07-13
    Publishing country England
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604625-3
    ISSN 1099-1263 ; 0260-437X
    ISSN (online) 1099-1263
    ISSN 0260-437X
    DOI 10.1002/jat.4035
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Preself-Feeding Medaka Fry Provides a Suitable Screening System for

    Myosho, Taijun / Ishibashi, Ayaka / Fujimoto, Shingo / Miyagawa, Shinichi / Iguchi, Taisen / Kobayashi, Tohru

    Environmental science & technology

    2022  Volume 56, Issue 10, Page(s) 6479–6490

    Abstract: Endocrine-disrupting chemicals are assessed based on their physiological potential and their potential associated adverse effects. However, suitable end points for detection of chemicals that interfere with the thyroid hormone (TH) system have not been ... ...

    Abstract Endocrine-disrupting chemicals are assessed based on their physiological potential and their potential associated adverse effects. However, suitable end points for detection of chemicals that interfere with the thyroid hormone (TH) system have not been established in nonmammals, with the exception of amphibian metamorphosis. The aims of the current study were to develop an
    MeSH term(s) Animals ; Ethinyl Estradiol/metabolism ; Oryzias/metabolism ; RNA, Messenger/metabolism ; Thyroid Hormones/metabolism ; Vitellogenins/metabolism
    Chemical Substances RNA, Messenger ; Thyroid Hormones ; Vitellogenins ; Ethinyl Estradiol (423D2T571U)
    Language English
    Publishing date 2022-04-27
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/acs.est.1c06729
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top