宮西 弘 (ミヤニシ ヒロシ)

MIYANISHI Hiroshi

写真a

職名

助教

研究室住所

宮崎県宮崎市学園木花台西1-1 S403

研究分野・キーワード

魚類生理学

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0985-58-7769

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  • 東京大学 -  博士(理学)

  • 横浜国立大学 -  修士(教育学)

  • 横浜国立大学 -  学士(教育)

 

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  • Functional classification of gill ionocytes and spatiotemporal changes in their distribution after transfer from seawater to freshwater in Japanese seabass

    Inokuchi M., Nakamura M., Miyanishi H., Hiroi J., Kaneko T.

    Journal of Experimental Biology   220 ( 24 ) 4720 - 4732   2017年12月

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     概要を見る

    © 2017. Published by The Company of Biologists Ltd . Spatiotemporal changes in branchial ionocyte distribution were investigated following transfer from seawater (SW) to freshwater (FW) in Japanese seabass. The mRNA expression levels of cystic fibrosis transmembrane conductance regulator (CFTR) and Na+//K+// 2Cl- cotransporter 1a (NKCC1a) in the gills rapidly decreased after transfer to FW, whereas Na+/H+ exchanger 3 (NHE3) and Na+/Cl- cotransporter 2 (NCC2) expression were upregulated following the transfer. Using quadruple-color whole-mount immunofluorescence staining with anti-Na+/K+/-ATPase, anti-NHE3, anti-CFTR and T4 (anti-NKCC1a/NCC2) antibodies, we classified ionocytes into one SW type and two FW types: NHE3 cell and NCC2 cell. Time course observation after transfer revealed an intermediate type between SWtype and FW-Type NHE3 ionocytes, suggesting functional plasticity of ionocytes. Finally, on the basis of the ionocyte classification of Japanese seabass, we observed the location of ionocyte subtypes on frozen sections of the gill filaments stained by triple-color immunofluorescence staining. Our observation indicated that SWtype ionocytes transformed into FW-Type NHE3 ionocytes and at the same time shifted their distribution from filaments to lamellae. However, FW-specific NCC2 ionocytes appeared mainly in the filaments. Taken together, these findings indicate that ionocytes originated from undifferentiated cells in the filaments and expanded their distribution to the lamellae during FW acclimation.

    DOI PubMed

  • 広塩性魚におけるin vivoコンディショナルノックダウンを用いた塩類細胞分化機構の解明

    宮西 弘, 高屋敷 早紀, 金子 豊二

    月刊海洋   49   202 - 207   2017年03月  [招待有り]

    共著

  • Past seawater experience enhances seawater adaptability in medaka, Oryzias latipes.

    Miyanishi H, Inokuchi M, Nobata S, Kaneko T

    Zoological letters   2   12   2016年

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    DOI PubMed

  • Appendage regeneration after autotomy is mediated by Baboon in the crayfish Procambarus fallax f. virginalis Martin, Dorn, Kawai, Heiden and Scholtz, 2010 (Decapoda: Astacoidea: Cambaridae)

    Shinji J., Miyanishi H., Gotoh H., Kaneko T.

    Journal of Crustacean Biology   36 ( 5 ) 649 - 657   2016年

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     概要を見る

    © 2016 Copyright 2016 by The Crustacean Society. Published by Brill NV, Leiden.Autotomy is an adaptive response in which animals escape from predators by shedding their own appendages. It is made possible by the presence of an efficient mechanism for regeneration. Decapod crustaceans frequently exhibit excellent abilities to regenerate complete pereopods in just a few molts following autotomy. The molecular basis of regeneration pereopods in decapods remains unclear. We identified the primary structure of Baboon (Babo), a type I TGF-β superfamily receptor involved in the activin pathway, in the crayfish, Procambarus fallax f. virginalis Martin, Dorn, Kawai, Heiden and Scholtz, 2010. Molecular cloning revealed that babo possesses three splice variants. The expression levels of the functional babo transcript did not show increases during regeneration. RNA interference (RNAi) targeting a common region of the babo sequence, however, caused a reduction in regenerated pereopod lengths. No loss or reduction in a specific article was observed. Instead, the regenerated legs were smaller but retained the morphology and proportions of regenerated legs from control animals. Babo thus appears to control the growth, but not the pattern, of legs during the regeneration process in decapod crustaceans.

    DOI

  • Teleocortin: A novel member of the CRH family in teleost fish

    Hosono K., Kikuchi Y., Miyanishi H., Hiraki-Kajiyama T., Takeuchi A., Nakasone K., Maehiro S., Okubo K.

    Endocrinology   156 ( 8 ) 2949 - 2957   2015年08月

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     概要を見る

    The CRH family of neuropeptides, including CRH and urocortins, plays pivotal roles in the regulation of physiological and behavioral stress responses in vertebrates. In this study, we identified a previously undescribed member of the CRH family of peptides in a teleost fish species (medaka; Oryzias latipes) and named this peptide teleocortin (Tcn). Medaka Tcn is a 41-amino acid polypeptide derived from the C terminus of a larger precursor protein that is encoded by a 2-exon gene, thus sharing common structural features with known CRH family peptides. tcn was found exclusively in teleost fish. Phylogenetic analysis suggested that tcn probably has an ancient origin but was lost from the tetrapod lineage shortly after the divergence of the teleost and tetrapod lineages. In the medaka brain, tcn was expressed in nuclei of the telencephalon, preoptic area, hypothalamus, tegmentum,andisthmic region. Becausenoneof these nuclei have been implicated in the control of ACTH secretion from the pituitary, Tcn may exert its effects centrally in the brain rather than via stimulation of the pituitary-adrenal/interrenal axis. Most, if not all, tcn-expressing neurons also expressed crh, suggesting that Tcn and Crh share common physiological functions. Moreover, Tcn activated Crh receptors 1 and 2 with equivalent or slightly higher potency than Crh, further suggesting that these peptides share common functions. Taken together, these data identified Tcn as a novel, teleost-specific member of the CRH family of peptides that may act centrally with Crh to regulate physiological and behavioral stress responses.

    DOI PubMed

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