Publications by authors named "Yasuhiko Ohta"

103 Publications

[Immunoglobulin G4( IgG4)-related Fibrosing Mediastinitis Localized in the Retrosternal Area:Report of a Case].

Kyobu Geka 2021 Apr;74(4):317-320

Department of Thoracic Surgery, Kanazawa Medical Center, Kanazawa, Japan.

An 84-year-old man was referred to our out-patient clinic with an elongated mass localized to the retrosternal area that was incidentally identified by computed tomography. On 18F-fluorodeoxyglucose-positron emission tomography, this lesion showed intense tracer uptake. Thus, a surgical biopsy under thoracoscopy was performed. Histological examination revealed dense fibrous tissue associated with inflammatory cell infiltration. The immunoglobulin (Ig) G4/IgG plasma cell ratio was over 90%. Serum IgG4 levels were normal. According to the Umehara criteria for IgG4-related disease, a final diagnosis of a "possible" IgG4-related fibrosing mediastinitis was made. Oral glucocorticoid treatment with 30 mg/day prednisolone reduced the mass.
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April 2021

Consecutive sexual maturation observed in a rock shell population in the vicinity of the Fukushima Daiichi Nuclear Power Plant, Japan.

Sci Rep 2021 Jan 12;11(1):560. Epub 2021 Jan 12.

Faculty of Agriculture, Tottori University, Tottori, Tottori, 680-8553, Japan.

In 2012, after the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) that followed the Tohoku earthquake and tsunami in March 2011, no rock shell (Thais clavigera; currently recognized as Reishia clavigera; Gastropoda, Neogastropoda, Muricidae) specimens were found near the plant from Hirono to Futaba Beach (a distance of approximately 30 km). In July 2016, however, rock shells were again found to inhabit the area. From April 2017 to May 2019, we collected rock shell specimens monthly at two sites near the FDNPP (Okuma and Tomioka) and at a reference site ~ 120 km south of the FDNPP (Hiraiso). We examined the gonads of the specimens histologically to evaluate their reproductive cycle and sexual maturation. The gonads of the rock shells collected at Okuma, ~ 1 km south of the FDNPP, exhibited consecutive sexual maturation during the 2 years from April 2017 to May 2019, whereas sexual maturation of the gonads of specimens collected at Hiraiso was observed only in summer. The consecutive sexual maturation of the gonads of the specimens collected at Okuma might not represent a temporary phenomenon but rather a site-specific phenotype, possibly caused by specific environmental factors near the FDNPP.
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http://dx.doi.org/10.1038/s41598-020-80686-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7803997PMC
January 2021

Changes in feeding habits of the starspotted smooth-hound, Mustelus manazo, in Tokyo Bay between periods with different stock size levels.

Mar Pollut Bull 2020 Mar 17;152:110863. Epub 2020 Feb 17.

Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki 305-8506, Japan.

We investigated differences in the feeding habits of the starspotted smooth-hound, Mustelus manazo, in Tokyo Bay between the mid-1990s (low stock size) and the late 2000s (high stock size). The frequency of M. manazo with empty stomachs increased from 5.9% in the mid-1990s to 16.1% in the late 2000s. A decrease in the relative weight of the stomach contents was evident from the mid-1990s to the late 2000s, especially in the small size classes, along with changes in the species composition in the stomach contents. Although crustaceans were the main constituents of the stomach contents, the proportion of crabs increased while those of shrimps and hermit crabs decreased. Changes in the feeding habits of M. manazo may be associated with shifts in the benthic community structure in Tokyo Bay.
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http://dx.doi.org/10.1016/j.marpolbul.2019.110863DOI Listing
March 2020

[Thymoma Presenting Synchronously with a Mycosis Fungoides;Report of a Case].

Kyobu Geka 2020 Jun;73(6):466-470

Department of Thoracic Surgery, Kanazawa Medical Center, Kanazawa, Japan.

A 65-year-old woman presented with mycosis fungoides and an anterior mediastinal tumor. Stage Ⅱa mycosis fungoides was treated with bath psoralen plus ultraviolet A, topical corticosteroids, and oral bexarotene. One month later, a surgical resection was performed for the anterior mediastinal tumor, which was a stage Ⅱ thymoma with membrane invasion. Furthermore, adjuvant radiotherapy was performed for anterior mediastinum. The mycosis fungoides lesion exacerbated after 3 months;thus, chemotherapies were performed. The patient died of respiratory insufficiency due to multiple pulmonary metastases of mycosis fungoides 1 year after the operation.
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June 2020

Clinicopathological features of immunoglobulin G4-related pleural lesions and diagnostic utility of pleural effusion cytology.

Cytopathology 2019 05 8;30(3):285-294. Epub 2018 Nov 8.

Department Thoracic surgery of National Hospital Organization, Kanazawa Medical Center, Kanazawa, Japan.

Objective: Immunoglobulin (Ig)G4-related disease is a recently described systemic immune-mediated fibro-inflammatory disease that frequently occurs in tumorous form. Herein, we elucidated the clinicopathological and cytological characteristics of IgG4-related pleural lesions (PLs).

Patients And Methods: Among 22 patients with fibro-inflammatory PLs of idiopathic aetiology, eight cases were diagnosed as IgG4-PL and the remaining 14 as non-IgG4-PL according to comprehensive diagnostic criteria for IgG4-related disease. Cell block examination of pleural effusion (CBPE) was performed in five patients with IgG4-PL and in six with non-IgG4-PL. Both groups were compared in terms of clinical presentation, laboratory data, histopathological features of resected pleura, and cytological features of pleural effusion (PE).

Results: PE was the most common (six patients, 75%) clinical presentation of IgG4-PL. IgG4-PL comparatively showed significantly more frequent concomitant allergic disease (P = .021), higher serum IgE levels (P = .012), higher adenosine deaminase levels in pleural fluid (P = .005), and rare spontaneous recovery without treatment (P = .046). The IgG4-PL group was histologically characterised by thicker fibrous pleura, storiform fibrosis, and infiltration of regulatory T cells, eosinophils and basophils. Using CBPE, IgG4-PL was cytologically distinct with numerous IgG4+ cells and eosinophils. The cytology of CBPE positively correlated with the histology of pleural tissue in the number of IgG4+ cells and eosinophils (R = .769 and .803, respectively).

Conclusion: IgG4-PL frequently presents with PE and is histologically and cytologically characterised by abundant infiltration of IgG4+ cells and eosinophils. We believe that CBPE with immunohistochemistry/special staining could assist in the auxiliary diagnosis of IgG4-PL.
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http://dx.doi.org/10.1111/cyt.12641DOI Listing
May 2019

Characterization and comparison of transcriptional activities of the retinoid X receptors by various organotin compounds in three prosobranch gastropods; Thais clavigera, Nucella lapillus and Babylonia japonica.

Aquat Toxicol 2018 Jun 26;199:103-115. Epub 2018 Mar 26.

Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan. Electronic address:

Two cDNAs of RXR were isolated, for the first time, from the ivory shell, Babylonia japonica, and the transcriptional activities were tested in vitro to compare with other gastropod (Thais clavigera and Nucella lapillus) RXR isoforms. The transcriptional activities of all of these RXR isoforms were significantly induced by mammalian RXR agonist, 9-cis retinoic acid (9cRA). The transcriptional activity of T. clavigera RXR-1 was also examined by using 9cRA and 16 organotin compounds, and significant ligand-dependent transactivations were observed by 9cRA and 5 organotins (tributyltin (TBT), tetrabutyltin (TeBT), tripropyltin (TPrT), tricyclohexyltin (TcHT) and triphenyltin (TPhT)). These 5 organotins also induced significant transcriptional activities in N. lapillus and B. japonica RXR isoforms. These 4 organotins, except for TeBT, have been reported to promote the development of imposex after a month of a single injection each, using female T. clavigera. To investigate the function of gastropod RXR isoforms, the effects of mammalian specific pan-agonist, PA024, and pan-antagonist, HX531, were examined, and significant induction of transcriptional activity by PA024 was demonstrated in these gastropod RXR isoforms. The additions of HX531 significantly suppressed the transcriptional activities of these gastropod RXR isoforms by 9cRA and 5 organotins. Using the mammalian two retinoic acid response elements, the transcriptional activities by 2 agonists, 9cRA and PA024, were different among the RXR isoforms of each gastropod species. With retinoid X response element (RXRE), transcriptional activities of TcRXR-1, BjRXR-1, and NlRXRa were significantly higher than those of TcRXR-2, BjRXR-2, and NlRXRb. Transcriptional activities of TcRXR-2, BjRXR-2, and NlRXRb, however, were significantly higher than those of TcRXR-1, BjRXR-1, and NlRXRa with thyroid hormone response element, TREpal. Thus, induction of imposex in prosobranch gastropods is strongly suggested to be triggered by 9cRA and certain organotins, such as TBT and TPhT through the activation of RXRs. These gastropod RXRs might control the different gene transcription by forming homo- or heterodimer complex with their own isoforms. These findings will contribute to our understanding of the fundamentals of the endocrine system in molluscs, particularly on RXR signaling pathway.
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http://dx.doi.org/10.1016/j.aquatox.2018.03.029DOI Listing
June 2018

Molecular cloning and characterization of the aryl hydrocarbon receptors and aryl hydrocarbon receptor nuclear translocators in the American alligator.

Gen Comp Endocrinol 2016 11 10;238:13-22. Epub 2016 May 10.

Graduate School of Life Science and Department of Biological Sciences, Hokkaido University, Sapporo, Japan. Electronic address:

Aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, binds to a variety of chemical compounds including various environmental contaminants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin. This receptor regulates expression of target genes through dimerization with the AHR nuclear translocator (ARNT). Since AHR-ARNT signaling pathways differ among species, characterization of AHR and ARNT is important to assess the effects of environmental contamination and for understanding the molecular mechanism underlying the intrinsic function. In this study, we isolated the cDNAs encoding three types of AHR and two types of ARNT from a reptile, the American alligator (Alligator mississippiensis). In vitro reporter gene assays showed that all complexes of alligator AHR-ARNT were able to activate ligand-dependent transcription on a xenobiotic response element. We found that AHR-ARNT complexes had higher sensitivities to a ligand than AHR-ARNT2 complexes. Alligator AHR1B showed the highest sensitivity in transcriptional activation induced by indigo when compared with AHR1A and AHR2. Taken together, our data revealed that all three alligator AHRs and two ARNTs were functional in the AHR signaling pathway with ligand-dependent and isoform-specific transactivations in vitro.
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http://dx.doi.org/10.1016/j.ygcen.2016.05.002DOI Listing
November 2016

Characterization of evolutionary trend in squamate estrogen receptor sensitivity.

Gen Comp Endocrinol 2016 11 9;238:88-95. Epub 2016 Apr 9.

Department of Basic Biology, Faculty of Life Science, SOKENDAI (Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan; Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan. Electronic address:

Steroid hormones are a key regulator of reproductive biology in vertebrates, and are largely regulated via nuclear receptor families. Estrogen signaling is regulated by two estrogen receptor (ER) subtypes alpha and beta in the nucleus. In order to understand the role of estrogen in vertebrates, these ER from various species have been isolated and were functionally analyzed using luciferase reporter gene assays. Interestingly, species difference in estrogen sensitivity has been noted in the past, and it was reported that snake ER displayed highest estrogen sensitivity. Here, we isolated additional ER from three lizards: chameleon (Bradypodion pumilum), skink (Plestiodon finitimus), and gecko (Gekko japonicus). We have performed functional characterization of these ERs using reporter gene assay system, and found high estrogen sensitivity in all three species. Furthermore, comparison with results from other tetrapod ER revealed a seemingly uniform gradual pattern of ligand sensitivity evolution. In silico 3D homology modeling of the ligand-binding domain revealed structural variation at three sites, helix 2, and juncture between helices 8 and 9, and caudal region of helix 10/11. Docking simulations indicated that predicted ligand-receptor interaction also correlated with the reporter assay results, and overall squamates displayed highest stabilized interactions. The assay system and homology modeling system provides tool for in-depth comparative analysis of estrogen function, and provides insight toward the evolution of ER among vertebrates.
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http://dx.doi.org/10.1016/j.ygcen.2016.04.005DOI Listing
November 2016

TRPV4 associates environmental temperature and sex determination in the American alligator.

Sci Rep 2015 Dec 18;5:18581. Epub 2015 Dec 18.

Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki Aichi 444-8787 Japan.

Temperature-dependent sex determination (TSD), commonly found among reptiles, is a sex determination mode in which the incubation temperature during a critical temperature sensitive period (TSP) determines sexual fate of the individual rather than the individual's genotypic background. In the American alligator (Alligator mississippiensis), eggs incubated during the TSP at 33 °C (male producing temperature: MPT) yields male offspring, whereas incubation temperatures below 30 °C (female producing temperature: FPT) lead to female offspring. However, many of the details of the underlying molecular mechanism remains elusive, and the molecular link between environmental temperature and sex determination pathway is yet to be elucidated. Here we show the alligator TRPV4 ortholog (AmTRPV4) to be activated at temperatures proximate to the TSD-related temperature in alligators, and using pharmacological exposure, we show that AmTRPV4 channel activity affects gene expression patterns associated with male differentiation. This is the first experimental demonstration of a link between a well-described thermo-sensory mechanism, TRPV4 channel, and its potential role in regulation of TSD in vertebrates, shedding unique new light on the elusive TSD molecular mechanism.
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http://dx.doi.org/10.1038/srep18581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4683465PMC
December 2015

Identification and Characterization of the Androgen Receptor From the American Alligator, Alligator mississippiensis.

Endocrinology 2015 Aug 14;156(8):2795-806. Epub 2015 May 14.

Okazaki Institute for Integrative Bioscience (S.M., R.Y., Y.Og., T.I.), National Institute for Basic Biology, National Institutes of Natural Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan; Department of Obstetrics and Gynecology (S.K., B.M.D., L.J.G.), Medical University of South Carolina and Hollings Marine Laboratory, Charleston, South Carolina 29412; Department of Life Environmental Conservation (H.I.), Faculty of Agriculture, Ehime University, Matsuyama, Ehime 790-8566, Japan; Department of Biological Sciences (Y.K.), Hokkaido University, Sapporo 060-0810, Japan; and Department of Veterinary Medicine (Y.Oh.), Faculty of Agriculture, Tottori University, Tottori, Tottori 680-8553, Japan.

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. We showed that AmAR responded to all natural androgens and their effects were inhibited by cotreatment with antiandrogens, such as flutamide, p,p'-dichlorodiphenyldichloroethylene, and vinclozolin. Intriguingly, we found a spliced form of the AR 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.
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http://dx.doi.org/10.1210/en.2015-1037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4511131PMC
August 2015

Differing species responsiveness of estrogenic contaminants in fish is conferred by the ligand binding domain of the estrogen receptor.

Environ Sci Technol 2014 May 14;48(9):5254-63. Epub 2014 Apr 14.

Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, and Department of Basic Biology, The Graduate School for Advanced Studies (SOKENDAI) , Okazaki, Aichi 444-8787, Japan.

Exposure to estrogenic endocrine disrupting chemicals (EDCs) induces a range of adverse effects, notably on reproduction and reproductive development. These responses are mediated via estrogen receptors (ERs). Different species of fish may show differences in their responsiveness to environmental estrogens but there is very limited understanding on the underlying mechanisms accounting for these differences. We used custom developed in vitro ERα reporter gene assays for nine fish species to analyze the ligand- and species-specificity for 12 environmental estrogens. Transcriptonal activities mediated by estradiol-17β (E2) were similar to only a 3-fold difference in ERα sensitivity between species. Diethylstilbestrol was the most potent estrogen (∼ 10-fold that of E2) in transactivating the fish ERαs, whereas equilin was about 1 order of magnitude less potent in all species compared to E2. Responses of the different fish ERαs to weaker environmental estrogens varied, and for some considerably. Medaka, stickleback, bluegill and guppy showed higher sensitivities to nonylphenol, octylphenol, bisphenol A and the DDT-metabolites compared with cyprinid ERαs. Triclosan had little or no transactivation of the fish ERαs. By constructing ERα chimeras in which the AF-containing domains were swapped between various fish species with contrasting responsiveness and subsequent exposure to different environmental estrogens. Our in vitro data indicate that the LBD plays a significant role in accounting for ligand sensitivity of ERα in different species. The differences seen in responsiveness to different estrogenic chemicals between species indicate environmental risk assessment for estrogens cannot necessarily be predicted for all fish by simply examining receptor activation for a few model fish species.
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http://dx.doi.org/10.1021/es5002659DOI Listing
May 2014

The reproductive hormone cycle of adult female American alligators from a barrier island population.

Reproduction 2014 Jun 8;147(6):855-63. Epub 2014 Mar 8.

Department of BiologyUniversity of Florida, Gainesville, Florida, USASchool of Marine SciencesUniversity of Maine, 5751 Murray Hall, Orono, Maine 04469, USAInnovative Health ApplicationsKennedy Space Center, Merritt Island, Florida, USAInstitute of Environmental EcologyEnvironmental Risk Research Center, IDEA Consultants, Inc., Yaizu, Shizuoka, JapanFaculty of Fisheries SciencesHokkaido University, Hokkaido, JapanSchool of Marine ScienceKitasato University, Kanagawa, JapanDepartment of Veterinary MedicineFaculty of Agriculture, Tottori University, Tottori, JapanDepartment of Basic BiologyFaculty of Life Science, The Graduate School for Advanced Studies (SOKENDAI), Okazaki, Aichi, JapanOkazaki Institute for Integrative BioscienceNational Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, JapanHollings Marine LaboratoryDepartment of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, South Carolina, USADepartment of BiologyUniversity of Florida, Gainesville, Florida, USASchool of Marine SciencesUniversity of Maine, 5751 Murray Hall, Orono, Maine 04469, USAInnovative Health ApplicationsKennedy Space Center, Merritt Island, Florida, USAInstitute of Environmental EcologyEnvironmental Risk Research Center, IDEA Consultants, Inc., Yaizu, Shizuoka, JapanFaculty of Fisheries SciencesHokkaido University, Hokkaido, JapanSchool of Marine ScienceKitasato University, Kanagawa, JapanDepartment of Veterinary MedicineFaculty of Agriculture, Tottori University, Tottori, JapanDepartment of Basic BiologyFaculty of Life Science, The Graduate School for Advanced Studies (SOKENDAI), Okazaki, Aichi, JapanOkazaki Institute for Integrative BioscienceNational Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, JapanHollings Marine LaboratoryDepartment of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, South Carolina, USA.

Comparatively, little data are available detailing the geographic variation that exists in the reproductive endocrinology of adult alligators, especially those living in barrier islands. The Merritt Island National Wildlife Refuge (MI) is a unique barrier island environment and home to the Kennedy Space Center (FL, USA). Seasonal patterns of sex steroids were assessed in adult female American alligators from MI monthly from 2008 to 2009, with additional samples collected at more random intervals in 2006, 2007, and 2010. Plasma 17β-estradiol and vitellogenin concentrations peaked in April, coincident with courtship and mating, and showed patterns similar to those observed in adult female alligators in other regions. Plasma concentrations of progesterone, however, showed patterns distinctly different than those reported for alligator populations in other regions and remained relatively constant throughout the year. Plasma DHEA peaked in July around the time of oviposition, decreased in August, and then remained constant for the remaining months, except for a moderate increase in October. Circulating concentrations of DHEA have not been previously assessed in a female crocodilian, and plasma concentrations coincident with reproductive activity suggest a reproductive and/or behavioral role. Interestingly, plasma testosterone concentrations peaked in May of 2008, as has been shown in female alligator populations in other regions, but showed no peak in 2009, demonstrating dramatic variability from year to year. Surveys showed 2009 to be particularly depauperate of alligator nests in MI, and it is possible that testosterone could serve as a strong indicator of breeding success.
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http://dx.doi.org/10.1530/REP-14-0031DOI Listing
June 2014

Cloning and characterization of the retinoic acid receptor-like protein in the rock shell, Thais clavigera.

Aquat Toxicol 2013 Oct 16;142-143:403-13. Epub 2013 Sep 16.

Center for Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.

The organotin compounds have a high affinity for the retinoid X receptor (RXR), which is a transcriptional factor activated by retinoids that induce imposex in gastropods. However, the molecular mechanisms underlying the regulation of RXR and its related genes in gastropods remain unclear. We isolated a retinoic acid receptor (RAR)-like cDNA (TcRAR) in the rock shell, Thais clavigera, and examined the transcriptional activity of the TcRAR protein by using all-trans retinoic acid (ATRA). However, we did not observe any ligand-dependent transactivation by this protein. We also examined the transcriptional activity of the TcRAR-ligand binding domain fused with the GAL4-DNA binding domain by using retinoic acids, retinol, and organotins and again saw no noteworthy transcriptional induction by these chemicals. Use of a mammalian two-hybrid assay to assess the interaction of the TcRAR protein with the TcRXR isoforms suggested that TcRAR might form a heterodimer with the RXR isoforms. The transcriptional activity of domain-swapped TcRAR chimeric proteins (the A/B domain of TcRAR combined with the D-F domain of human RARα) was also examined and found to be ATRA-dependent. These results suggest that TcRAR is not activated by retinoic acids, but can form a heterodimer with TcRXR isoforms. These data contribute to our understanding of the mechanism by which RXR functions in gastropods.
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http://dx.doi.org/10.1016/j.aquatox.2013.09.008DOI Listing
October 2013

Development of reproductive organs in the ivory shell Babylonia japonica: observations from wild populations and laboratory-reared juveniles.

Mar Environ Res 2014 Feb 23;93:4-14. Epub 2013 Jul 23.

Center for Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.

We histologically examined normal differentiation and development of genital tract and gonad in the ivory shell Babylonia japonica (Buccinidae) to determine whether the formation of male-type genitalia in imposex-exhibiting females mimics the normal development of male genitalia in prosobranch gastropods. We used a wild-caught 2-year-old specimen and laboratory-reared juveniles aged 0-24 months. Gonad differentiation was unclear before age 14 months, but progressed after 16 months. Both sexes had complete genital tract and mature gonad at 20 months. However, differentiation and development occurred earlier in females than in males. Development of genital tract preceded gonad differentiation. Vas deferens morphogenesis in males resembled that in imposex-exhibiting females. These findings help to understand the morphogenesis of genital tract and gonad in prosobranch gastropods and will contribute to more in-depth studies of the mode of action of organotin compounds such as TBT and TPhT in imposex development in female prosobranch gastropods.
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http://dx.doi.org/10.1016/j.marenvres.2013.07.003DOI Listing
February 2014

[Covering technique using an absorbable sheet for patients with spontaneous pneumothorax (onepoint fixation at the center of the sheet)].

Kyobu Geka 2012 Dec;65(13):1139-41

Department of General Thoracic Surgery, National Hospital Organization, Kanazawa Medical Center, Kanazawa, Japan.

Effective surgical treatment for spontaneous pneumothorax requires control of the postoperative recurrent bulla. Currently, a covering method using an absorbable sheet is a well-recognized form of operative procedure to prevent recurrence. However, the technique used in covering methods appears to be complicated. Here, we present a simple covering method. Using a suture as a guide, we can easily and correctly induce the sheet to the targeting area. Fixation is made at only 1 point at the center of the sheet. To date, we have applied this covering method to 57 patients. Recurrence was recognized in 3 patients( 5.3%) over a mean follow-up period of 12 months.
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December 2012

Sequential changes in the expression of Wnt- and Notch-related genes in the vagina and uterus of ovariectomized mice after estrogen exposure.

In Vivo 2012 Nov-Dec;26(6):899-906

Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Kojirakawa-machi, Yamagata, Japan.

Estrogen regulates morphological changes in reproductive organs, such as the vagina and uterus, during the estrous cycles in mice. Estrogen depletion by ovariectomy in adults results in atrophy accompanied by apoptosis in vaginal and uterine cells, while estrogen treatment following ovariectomy elicits cell proliferation in both organs. Sequential changes in mRNA expression of wingless-related MMTV integration site (Wnt) and Notch signaling genes were analyzed in the vagina and uterus of ovariectomized adult mice after a single injection of 17β-estradiol to provide understanding over the molecular basis of differences in response to estrogen in these organs. We found estrogen-dependent up-regulation of Wnt4, Wnt5a and p21 and down-regulation of Wnt11, hairy/enhancer-of-split related with YRPW motif-1 (Hey1) and delta-like 4 (Dll4) in the vagina, and up-regulation of Wnt4, Wnt5a, Hey1, Heyl, Dll1, p21 and p53 and down-regulation of Wnt11, Hey2 and Dll4 in the uterus. The expression of Wnt4, Hey1, Hey2, Heyl, Dll1 and p53 showed different patterns after the estrogen injection. Expression patterns for Wnt5a, Wnt11, Dll4 and p21 in the vagina and uterus were similar, suggesting that these genes are involved in the proliferation of cells in both those organs in mice.
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May 2013

Developmental disorders and altered gene expression in the tropical clawed frog (Silurana tropicalis) exposed to 17α-ethinylestradiol.

J Appl Toxicol 2013 Sep 6;33(9):1001-10. Epub 2012 Nov 6.

The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi, Yamaguchi, 753-8513, Japan.

Several endocrine-disrupting chemicals with estrogenic activity can affect sexual development and reproduction in aquatic wildlife. The occurrence of oocytes in the testis (testis-ova) is one reproductive disorder and can be used as a valid endpoint when studying disruptive effects of estrogenic chemicals. To elucidate the molecular basis of testis-ova induction, we conducted gene expression analysis in the gonads of Silurana tropicalis exposed to 0, 3, 10 and 30 ng l(-1) 17α-ethinylestradiol (EE2) from 2 days after fertilization to the juvenile stage (14 weeks after fertilization). The frequencies of testis-ova induction or male to female sex-reversal of the gonads increased in an EE2 dose-dependent manner. Microarray analysis showed that expressions of a large number of genes were significantly changed by EE2 exposure. Genes including egg envelope composition (zp4, zpax, zpc, zp3.2 and egg cortical granule lectin), 42S particle genes (42Sp50, 42Sp43 and 42Sp48) and regulation of female germ cells (figla) are associated with the testis-ova and sex-reversal situation in the gonads. Of those, expression of zpc and 42Sp50 genes is associated with testis-ova. Thus, we propose that these genes are useful biomarkers for toxicological research in amphibians developmentally exposed to estrogenic chemicals.
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http://dx.doi.org/10.1002/jat.2836DOI Listing
September 2013

Molecular cloning and characterization of the corticoid receptors from the American alligator.

Mol Cell Endocrinol 2013 Jan 2;365(2):153-61. Epub 2012 Nov 2.

Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.

Steroid hormones are essential for health in vertebrates. Corticosteroids, for example, have a regulatory role in many physiological functions, such as osmoregulation, respiration, immune responses, stress responses, reproduction, growth, and metabolism. Although extensively studied in mammals and some non-mammalian species, the molecular mechanisms of corticosteroid hormone (glucocorticoids and mineralocorticoids) action are poorly understood in reptiles. Here, we have evaluated hormone receptor-ligand interactions in the American alligator (Alligator mississippiensis), following the isolation of cDNAs encoding a glucocorticoid receptor (GR) and a mineralocorticoid receptor (MR). The full-length alligator GR (aGR) and aMR cDNAs were obtained using 5' and 3' rapid amplification cDNA ends (RACE). The deduced amino acid sequences exhibited high identity to the chicken orthologs (aGR: 83%; aMR: 90%). Using transient transfection assays of mammalian cells, both aGR and aMR proteins displayed corticosteroid-dependent activation of transcription from keto-steroid hormone responsive, murine mammary tumor virus promoters. We further compared the ligand-specifity of human, chicken, Xenopus, and zebrafish GR and MR. We found that the alligator and chicken GR/MR have very similar amino acid sequences, and this translates to very similar ligand specificity. This is the first report of the full-coding regions of a reptilian GR and MR, and the examination of their transactivation by steroid hormones.
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http://dx.doi.org/10.1016/j.mce.2012.10.014DOI Listing
January 2013

Establishment of transactivation assay systems using fish, amphibian, reptilian and human thyroid hormone receptors.

J Appl Toxicol 2013 Sep 30;33(9):991-1000. Epub 2012 Oct 30.

Integrated Environmental Risk Research Section, Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.

Thyroid hormones are essential for the regulation of a wide range of biological processes associated with normal development and metabolism in vertebrates. For the screening of chemicals with a potential thyroid hormone and anti-thyroid hormone activities, we have established transient transactivation assay systems using thyroid hormone receptors (TRα and TRβ) from three frog species (Xenopus laevis, Silurana tropicalis and Rana rugosa), a fish (Oryzias latipes), an alligator (Alligator mississippiensis) and a human (Homo sapiens). In all species examined, similar transcriptional activities were found for triiodothyronine (T3 : 10(-11) M in TRα and 10(-10) M in TRβ) and thyroxine (T4 : 10(-9) M in TRα and 10(-8) M in TRβ). Analogs of thyroid hormone (3,5,3',-triiodothyroacetic acid and 3,3',5,5'-tetraiodothyroacetic acid) exhibited weaker activity, requiring 10-fold higher concentrations for induction of activity when compared with T3 and T4 . These results provide support for the usefulness of in vitro screening assay systems as part of an approach to test chemicals for potential thyroid hormone receptor activity. In addition, we observed that T3 -stimulated transcriptional activity of the O. latipes TRα was inhibited by 10(-5) M tetrabromobisphenol A (TBBPA). In contrast, TR antagonist activities on TRα were not encountered in other species, even with TBBPA concentrations at 10(-5) M. In vitro transactivation assay systems using TRs from various species can be used for the screening of chemicals with thyroid-receptor agonist and antagonist activities. They also can be used for studies that examine evolutionary differences among species in the potency of TR activation.
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http://dx.doi.org/10.1002/jat.2825DOI Listing
September 2013

p21 and Notch signalings in the persistently altered vagina induced by neonatal diethylstilbestrol exposure in mice.

J Vet Med Sci 2012 Dec 24;74(12):1589-95. Epub 2012 Jul 24.

Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Kojirakawa-machi, Yamagata 990-8560, Japan.

Female reproductive organs show organ-specific morphological changes during estrous cycles. Perinatal exposure to natural and synthetic estrogens including diethylstilbestrol (DES) or estrogenic chemicals induces estrogen-independent persistent proliferation of vaginal epithelium in mice. To understand the underlying mechanism of the estrogen-independent persistent vaginal changes induced by perinatal DES exposure, we examined global gene expressions in the vaginae of ovariectomized adult mice exposed neonatally to DES using a microarray. The cell cycle-related gene, p21, a cyclin-dependent kinase inhibitor, showed upregulation in the vagina, and p21 protein was localized in the basal layer of the vaginal epithelium in mice exposed neonatally to DES and an estrogen receptor α agonist, propyl pyrazole triol (PPT). The expressions of Notch receptors and Notch ligands were unchanged; however, the mRNAs of hairy-related basic helix-loop-helix (bHLH) transcription factor genes, Hes1, Hey1 and Heyl were persistently downregulated in the vagina, indicating estrogen-independent epithelial cell proliferation in mice exposed neonatally to DES and PPT.
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http://dx.doi.org/10.1292/jvms.12-0182DOI Listing
December 2012

Wnt family genes and their modulation in the ovary-independent and persistent vaginal epithelial cell proliferation and keratinization induced by neonatal diethylstilbestrol exposure in mice.

Toxicology 2012 Jun 21;296(1-3):13-9. Epub 2012 Mar 21.

Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Kojirakawa-machi, Yamagata 990-8560, Japan.

Proliferation and differentiation of cells in female reproductive organs, the oviduct, uterus and vagina, are regulated by endogenous estrogen. In utero exposure to a synthetic estrogen, diethylstilbestrol (DES), induces vaginal clear-cell adenocarcinoma in humans. In mice, perinatal exposure to DES results in abnormalities such as polyovular follicles, uterine circular muscle disorganization and persistent vaginal epithelial cell proliferation. We reported the persistent gene expression change such as interleukin-1 (IL-1) related genes, insulin-like growth factor-I (IGF-I) and its downstream signaling in the mouse vagina exposed neonatally to DES. In this study, we found persistent up-regulation of Wnt4 and persistent down-regulation of Wnt11 in the vagina of mice exposed neonatally to DES and estrogen receptor α specific ligand. Also Wnt4 expression in vagina is correlated to the stratification of epithelial cells with the superficial keratinization of vagina, but not epithelial cell stratification only.
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http://dx.doi.org/10.1016/j.tox.2012.02.010DOI Listing
June 2012

Sugar expressions on the vaginal epithelium in pregnant mice.

J Vet Med Sci 2012 Jun 18;74(6):805-8. Epub 2012 Jan 18.

Department of Laboratory Animal Science, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan.

Sugar expressions were examined on the epithelium of both the middle portion of the vagina and the vaginal portion of the cervical canal (CC) in pregnant mice to understand the pathogenesis of bacterial infection in the female reproductive organ by using a panel of lectins. As a result, N-acetylglucosamine was positive before pregnant day (P) 7 but negative after P10 and at diestrus on both the vagina and the CC. In addition, some differences in sugar expressions were seen between them. These results suggest that sugar expressions on the mucosal surface would change not only site-specifically but also time-dependently, and these sugar differences indicate the possibility of the alteration of the settled bacterial species on the vaginal mucosa in pregnancy.
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http://dx.doi.org/10.1292/jvms.11-0562DOI Listing
June 2012

Gene expression profiles in the testis associated with testis-ova in adult Japanese medaka (Oryziaslatipes) exposed to 17α-ethinylestradiol.

Chemosphere 2012 May 9;87(7):668-74. Epub 2012 Jan 9.

The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8513, Japan.

The occurrence of oocytes in the testis (testis-ova) of several fish species is often associated with exposure of estrogenic chemicals. However, induction mechanisms of the testis-ova remain to be elucidated. To develop marker genes for detecting testis-ova in the testis, adult male medaka were exposed to nominal concentration of 100 ng L(-1) of 17α-ethinylestradiol (EE2) for 3-5 weeks, and 800 ng estradiol benzoate (EB) for 3 weeks (experiment I), and a measured concentration of 20 ng L(-1) EE2 for 1-6 weeks (experiment II). Histological analysis was performed for the testis, and microarray analyses were performed for the testis, liver and brain. Microarray analysis in the estrogen-exposed medaka liver showed vitellogenin and choriogenin as estrogen responsive genes. Testis-ova were induced in the testis after 4 weeks of exposure to 100 ng L(-1) EE2, 3 weeks of exposure to 800 ng EB, and 6 weeks of exposure to 20 ng L(-1) EE2. Microarray analysis of estrogen-exposed testes revealed up-regulation of genes related to zona pellucida (ZP) and the oocytes marker gene, 42Sp50. Using quantitative RT-PCR we confirmed that Zpc5 gene can be used as a marker for the detection of testis-ova in male medaka.
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http://dx.doi.org/10.1016/j.chemosphere.2011.12.047DOI Listing
May 2012

Lectin histochemistry for sugars on the mucosal surface of the uterus in pregnant mice.

J Vet Med Sci 2012 May 6;74(5):617-20. Epub 2011 Dec 6.

Department of Laboratory Animal Science, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan.

Expression patterns of sugars on the mucosal surface of the uterus in pregnant mice were investigated by using 21 kinds of lectins. In the uterine mucosa, the GlcNAc group tended to express a positive reaction before pregnant day 10, but the glucose/mannose group generally expressed a positive reaction after pregnant day 10. On the other hand, the fucose group expressed a negative reaction during all periods in pregnancy. These findings were almost the same on both the mesometrial side and anti-mesometrial side of the uterus. These differences of sugar expression probably reflect the functional change of the mucosa during pregnancy and the alteration of sugar expression may give a chance for pathogens to infect in the uterus with limited periods.
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http://dx.doi.org/10.1292/jvms.11-0461DOI Listing
May 2012

Vas deferens and penis development in the imposex-exhibiting female rock shell, Thais clavigera.

Mar Environ Res 2012 May 19;76:71-9. Epub 2011 Oct 19.

Center for Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.

The characteristics of the development of male genitalia (penis and vas deferens) in imposex-exhibiting female rock shells, Thais clavigera, were histologically examined using specimens from a wild population and tributyltin (TBT)-exposed females in the laboratory. A variety of vas deferens morphogenesis patterns were observed in wild female T. clavigera, and the characteristics were summarized. The immature vas deferens at an initial stage, however, was only observed beneath or behind the penis, and no vas deferens was observed close to the vaginal opening (i.e., vulva) of the capsule gland in TBT-exposed females, which was different from the characteristics of vas deferens formation observed in wild females. Taking into consideration both the observed results from wild female specimens and from TBT-exposed females in the laboratory, the vas deferens sequence (VDS) index for T. clavigera was proposed as VDS 1-6.
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http://dx.doi.org/10.1016/j.marenvres.2011.10.001DOI Listing
May 2012

Comparative responsiveness to natural and synthetic estrogens of fish species commonly used in the laboratory and field monitoring.

Aquat Toxicol 2012 Mar 28;109:250-8. Epub 2011 Sep 28.

University of Exeter, Biosciences, College of Life & Environmental Sciences, Exeter EX4 4PS, United Kingdom.

Exposure to estrogenic chemicals discharged into the aquatic environment has been shown to induce feminization in wild freshwater fish and although fish species have been reported to differ in their susceptibility for these effects, empirical studies that directly address this hypothesis are lacking. In this study, in vitro ERα activation assays were applied in a range of fish species used widely in chemical testing (including, zebrafish, fathead minnow, medaka) and/or as environmental monitoring species (including, roach, stickleback, carp) to assess their comparative responsiveness to natural (estrone, estradiol, estriol) and synthetic (17α-ethinylestradiol (EE2), diethylstilbestrol (DES)) estrogens. In vivo exposures to EE2 via the water (nominal 2 and 10 ng/L for 7 days) were also conducted for seven fish species to compare their responsiveness for hepatic vitellogenin (VTG) mRNA induction (an ER mediated response). Of the fish species tested, zebrafish ERα was found to be the most responsive and carp and stickleback ERα the least responsive to natural steroid estrogens. This was also the case for exposure to EE2 with an ERα-mediated response sensitivity order of zebrafish > medaka > roach > fathead minnow > carp > stickleback. For VTG mRNA induction in vivo, the order of species responsiveness was: rainbow trout (not tested in the ERα activation assays) > zebrafish > fathead minnow > medaka > roach > stickleback > carp. Overall, the responses to steroid estrogens in vitro via ERα compared well with those seen in vivo (VTG induction for exposure to EE2) showing in vitro screening of chemicals using fish ERα-mediated responses indicative of estrogenic responses (VTG induction) in vivo.
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http://dx.doi.org/10.1016/j.aquatox.2011.09.004DOI Listing
March 2012

Cloning and characterization of retinoid X receptor (RXR) isoforms in the rock shell, Thais clavigera.

Aquat Toxicol 2011 May 18;103(1-2):101-11. Epub 2011 Feb 18.

Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.

The organotin compounds tributyltin (TBT) and triphenyltin (TPT) belong to a diverse group of widely distributed environmental pollutants that induce imposex in gastropods. These organotins have high affinity for retinoid X receptor (RXR), which is a transcription factor activated by retinoids, such as 9-cis retinoic acid (9cRA), in vertebrates. However, the molecular mechanisms underlying the regulation of RXR by retinoids and organotins have not been clarified in gastropods. We isolated two isoforms of RXR cDNAs, RXR isoform 1 (TcRXR-1) and RXR isoform 2 (TcRXR-2), in the rock shell Thais clavigera. The deduced amino acid sequences of TcRXR-1 and TcRXR-2 are highly homologous with those of other gastropods. These TcRXR isoforms displayed 9cRA-dependent activation of transcription in a reporter gene assay using COS-1 cells. The transcriptional activity of TcRXR-2, the encoded protein of which has five additional amino acids in the T-box of the C domain, was significantly lower than that of TcRXR-1. Decreases of the transcriptional activity by TcRXR-1 were observed when more than equal amount of TcRXR-2 fused expression vector was existed in a co-transfection assay. Immunoblot analysis showed several shifted bands for TcRXR isoforms resulting from phosphorylation. Mutation of potential phosphorylation sites from serine to alanine in the A/B domain of TcRXR-1 showed that, in the S89A/S103A mutant, there was a band shift and significantly higher transcriptional activity than in the controls when stimulated with 9cRA. Our findings could contribute to a better understanding of the role of interactions between RXR and retinoids and organotins, not only in the induction mechanism of imposex in gastropods but also in the endocrinology of mollusks.
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http://dx.doi.org/10.1016/j.aquatox.2011.02.012DOI Listing
May 2011

Expression of CD38 with intracellular enzymatic activity: a possible explanation for the insulin release induced by intracellular cADPR.

Mol Cell Biochem 2011 Jun 9;352(1-2):293-9. Epub 2011 Mar 9.

Department of Laboratory Medicine, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan.

CD38 is a transmembrane glycoprotein expressed in multiple cell types, including pancreatic β cells. It can serve as an enzyme that catalyzes the metabolism of two different Ca(2+)-mobilizing compounds, cyclic adenosine diphosphoribose (cADPR) and nicotinic acid adenine dinucleotide phosphate. One of these metabolites, cADPR, is known to be involved in glucose-induced insulin secretion from pancreatic β cells. Although the essential role of CD38 for endogenous cADPR synthesis has been established, the relationship between the proposed extracellular enzymatic activity of CD38 and the intracellular Ca(2+) modulation caused by the intracellular cADPR accumulation has not yet been fully explained. For a better understanding of the role of CD38 in the insulin secretion machinery, analysis of the intracellular localization of this molecule in pancreatic β cells is essential. In an attempt to provide a method to probe the N-terminal and C-terminal of CD38 separately, we generated an insulin-secreting MIN6 murine pancreatic β cell line expressing a human CD38 bearing an N-terminal FLAG epitope tag. We found a weak but consistent expression of the FLAG epitope outside of the cells, indicating the presence of a small amount of CD38 with cytoplasmic enzymatic activity. MIN6 cells transfected with human CD38 exhibited increased glucose-induced insulin release. In addition, anti-FLAG cross-linking further enhanced the insulin release, suggesting that the N-terminal of CD38 expressed on the cell surface functions as a receptor for an unknown ligand and triggers positive signals for insulin secretion.
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http://dx.doi.org/10.1007/s11010-011-0765-xDOI Listing
June 2011

Sex steroid and thyroid hormone receptor expressions in the thyroid of the American alligator (Alligator mississippiensis) during different life stages.

J Morphol 2011 Jun 9;272(6):698-703. Epub 2011 Feb 9.

Department of Biology, 220 Bartram Hall, University of Florida, Gainesville, FL 32611, USA.

The expression of estrogen receptors, ESR1 (ERα) and ESR2 (ERβ), and androgen receptors (AR) in the thyroid gland has been reported in few vertebrate species other than a few mammals. This study reports the presence of sex steroid hormone receptors and thyroid receptors (ERα, ERβ, AR, TRα, and TRβ) in the thyroid gland of the American alligator at several life stages. It provides a semiquantification and distribution of ERα in the thyroid follicle cells using an immunohistochemical approach as well as reports quantitative differences in mRNA expression of ERα, ERβ, TRα, TRβ, and AR in the same tissue using quantitative real time-PCR (Q-PCR) with primers designed specifically for alligators. The thyroid tissue of the American alligator expresses ERα, ERβ, and AR at all of the life stages examined here although no statistically significant differences were observed between male and female in thyroid mRNA expression for any of the genes analyzed. No sexual dimorphism was observed in ERα immunostaining. No statistical analysis across life stages were performed due to confounding factor of season.
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http://dx.doi.org/10.1002/jmor.10936DOI Listing
June 2011

Molecular cloning of anti-Müllerian hormone from the American alligator, Alligator mississippiensis.

Mol Cell Endocrinol 2011 Feb 25;333(2):190-9. Epub 2010 Dec 25.

Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.

Anti-Müllerian hormone (AMH) plays an important role in male sex differentiation in vertebrates. AMH produced by Sertoli cells of the fetal testis induces regression of the Müllerian duct in mammalian species. In alligators, sexual differentiation is controlled by the temperature during egg incubation, termed temperature-dependent sex determination (TSD). The TSD mechanism inducing sex differentiation is thought to be unique and different from that of genetic sex determination as no gene such as the SRY of mammals has been identified. However, many of the genes associated with gonadal differentiation in mammals also are expressed in the developing gonads of species exhibiting TSD. To clarify the molecular mechanisms associated with gonad formation during the temperature-sensitive period (TSP), we have cloned the full length AMH gene in the alligator, and quantitatively compared mRNA expression patterns in the gonad-adrenal-mesonephros (GAM) complex isolated from alligator embryos incubated at male and female producing temperatures. The deduced amino acid sequence of the alligator AMH cDNA showed high identity (59-53%) to avian AMH genes. AMH mRNA expression was high in the GAM of male alligator embryos at stage 24 (immediately after sex determination) and hatchlings, but suppressed in the GAM of estrogen-exposed hatchlings incubated at the male-producing temperature. In the alligator AMH proximal promoter, a number of transcriptional factors (for SF-1. GATA, WT-1 and SOX9) binding elements were also identified and they exhibit a conserved pattern seen in other species. SOX9 up-regulates transcriptional activity through the amAMH promoter region. These results suggested that AMH and SOX9 play important roles in TSD of the American alligator.
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http://dx.doi.org/10.1016/j.mce.2010.12.025DOI Listing
February 2011