論文 - 内田 勝久
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Uchida K., Kaneko T., Miyazaki H., Hasegawa S., Hirano T.
Zoological Science 17 ( 2 ) 149 - 160 2000年3月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zoological Science
Changes in morphology and cellular activity of the chloride cells in branchial and opercular epithelia were examined in tilapia, Oreochromis mossambicus, adapted to fresh water (FW), seawater (SW) and concentrated SW (180% SW). The tilapia are adaptable to a wide range of salinity, maintaining the plasma osmolality within physiological levels. Gill Na + , K + -ATPase activity was remarkably increased in response to elevated environmental salinity. Using immunocytochemical staining with an antiserum specific for α-subunit of Na + , K + -ATPase, chloride cells were detected on the afferent half of the filament epithelia. The size of immunoreactive chloride cells was twice larger in SW and four times larger in 180% SW than in FW. Confocal laser scanning microscopic observations revealed the frequent occurrence of chloride cell complexes under hypersaline conditions. By electron microscopy, a deeply invaginated apical crypt and well-developed tubular network were observed in chloride cells of SW- and 180% SW-adapted fish, indicating enhanced cellular activity. Chloride cells present in the opercular membrane were also developed in response to increased salinity. These findings suggest that highly activated chloride cells in branchial and opercular epithelia may be responsible for salt secretion in hyperosmotic environments. The excellent salinity tolerance of tilapia appears to be attributed to their ability to develop chloride cells in response to increased environmental salinity.
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Shift of chloride cell distribution during early life stages in seawater-adapted killifish, Fundulus heteroclitus. 査読あり
Katoh F., Shimizu A., Uchida K., Kanako T.
Zoological Science 17 11 - 18 2000年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Katoh F., Shimizu A., Uchida K., Kaneko T.
Zoological Science 17 ( 1-12 ) 11 - 18 2000年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zoological Science
The shift of chloride cell distribution was investigated during early life stages of seawater-adapted killifish (Fundulus heteroclitus). Chloride cells were detected by immunocytochemistry with an antiserum specific for Na + , K + -ATPase in whole-mount preparations and paraffin sections. Chloride cells first appeared in the yolk-sac membrane in the early embryonic stage, followed by their appearance in the body skin in the late embryonic stage. Immunoreactive chloride cells in the yolk-sac membrane and body skin often formed multicellular complexes, as evidenced by the presence of more than one nucleus. The principal site for chloride cell distribution shifted from the yolk-sac membrane and body skin during embryonic stages to the gill and opercular membrane in larval and later developmental stages. Our observations suggest that killifish embryos and newly-hatched larvae could maintain their ion balance through chloride cells present in the yolk-sac membrane and body skin until branchial and opercular chloride cells become functional.
DOI： 10.2108/zsj.17.11
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Acid tolerance of Japanese dace (a cyprinid teleost) in Lake Osorezan, a remarkable acid lake. 査読あり
Kaneko T., Hasegawa S., Uchida K., Ogasawara T., Oyagi A., Hirano T.
Zoological Science 16 871 - 877 1999年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Acid tolerance of Japanese dace (a cyprinid teleost) in Lake Osorezan, a remarkable acid lake
Kaneko T., Hasegawa S., Uchida K., Ogasawara T., Oyagi A., Hirano T.
Zoological Science 16 ( 6 ) 871 - 877 1999年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zoological Science
The Japanese dace (Tribolodon hakonensis) is the only teleost species that inhabits Lake Osorezan, a remarkable acid lake in Japan with the water pH of 3.4-3.8. In the present study, physiological changes following transfer of the dace acclimated to neutral stream water (pH 6.8-7.2) to acid lake water (pH 3.6-3.7) were examined with special reference to changes in gill chloride cell morphology. The dace survived direct transfer to acid lake water for 3 days. Plasma [Na + ] and [Cl - ] showed transient decreases at 1 hr after transfer; however, the decrease in [Na + ] was greater than that in [Cl - ]. The recovery of [Cl - ] was more evident than that of [Na + ]. The transient decreases of plasma [Na + ] and [Cl - ] were followed by acidosis. Blood pH was decreased by 0.13 unit at 6 hr, but partially restored by 24 hr. In the dace acclimated to neutral stream water, chloride cells were scattered in the gill filament. Following transfer to acid lake water, however, well-developed chloride cells were arranged in a radial fashion, forming follicular or gland-like structures in the gills. Each chloride cell was equipped with an apical pit, which faced a common lumen leading to the external environment. These findings provide morphological evidence for a significant role(s) of gill chloride cells in ion and acid-base regulation in the acid-tolerant dace.
DOI： 10.2108/zsj.16.871
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Hiroi J., Kaneko T., Uchida K., Hasegawa S., Tanaka M.
Zoological Science 15 ( 4 ) 447 - 453 1998年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zoological Science
To investigate the involvement of the yolk-sac membrane in ion absorption, developmental changes in whole-body cation contents, cellular localization of vacuolar-type H + -ATPase (V-ATPase), and size and density of pavement and chloride cells in the yolk-sac membrane were examined in tilapia (Oreochromis mossambicus) larvae in fresh water (FW) and those transferred to seawater (SW) at 2 days before hatching (day-2). The whole-body content of Na + in embryos and larvae adapted to both FW and SW increased constantly from day-2 to day 10, although they were not fed through the experiment. The yolk-sac membrane of FW larvae at days 0 and 2 showed V-ATPase immunoreactivity in pavement cells, but not in chloride cells. No positive immunoreactivity was detected in SW larvae. Whole-mount immunocytochemistry showed that some pavement cells were intensively immunoreactive, whereas others were less or not immunoreactive. Electron-microscopic immunocytochemistry revealed that V-ATPase immunoreactivity was present in the apical regions of pavement cells in FW larvae, especially in their ridges. The pavement cells in FW larvae were significantly smaller in size but higher in density than those in SW. These results suggest that pavement cells are the site of active Na + uptake in exchange for H + secretion through V-ATPase in FW-adapted tilapia during early life stages.
DOI： 10.2108/zsj.15.447
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Immunolocalization of vacuolar-type H+-ATPase in the yolk-sac membrane of tilapia (Oreochromis mossambicus) larvae. 査読あり
Hiroi, J., Kaneko T., Uchida K., Hasegawa S., Tanaka M.
Zoological Science 15 447 - 453 1998年5月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Localization of cortisol receptor in branchial chloride cells in chum salmon fry. 査読あり
Uchida K., Kaneko T., Tagawa M., Hirano T.
General and Comparative Endocrinology 109 175 - 185 1998年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Localization of cortisol receptor in branchial chloride cells in chum salmon fry
Uchida K., Kaneko T., Tagawa M., Hirano T.
General and Comparative Endocrinology 109 ( 2 ) 175 - 185 1998年2月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：General and Comparative Endocrinology
To clarify the involvement of cortisol in functional differentiation of branchial chloride cells, cellular gene expression and localization of cortisol receptor were examined in chum salmon (Oncorhynchus keta) fry in freshwater (FW) and those adapted to seawater (SW) by in situ hybridization and immunocytochemical staining. Sodium-potassium adenosinetriphosphatase (Na + , K + -ATPase) activity in the whole gill homogenate was significantly higher in SW fish than in FW fish. There were no significant differences in plasma cortisol levels nor in the expression of cortisol receptor mRNA, examined by Northern blot analysis, between SW and FW fish. The receptor gene expression, examined by in situ hybridization with b iotin-labeled synthetic oligonucleotide probe, and specific immunostaining with anticortisol receptor serum were found in two types of chloride cells distributed in the gill filaments and lamellae, which were also labeled with anti-Na + ,K + -ATPase serum, indicating that cortisol may be one of the important factors regulating chloride cell functions. Gene expression of cortisol receptor in filament chloride cells, which were highly activated in SW-adapted fry, was significantly greater in the fry adapted to SW than in FW-adapted fry, reflecting their specific role in salt secretion in SW. Cortisol receptors were also present in undifferentiated cells in the interlamellar regions adjacent to the central venous sinus, also suggesting the involvement of cortisol in the functional differentiation of chloride cells.
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Functional differentiation of branchial chloride cells and its hormonal control in chum salmon.
Uchida K., Hirano T.
Marine Conservation and Resource Rehabilitation 35 - 39 1997年12月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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Localization of cortisol receptor in branchial chloride cells in chum salmon.
Uchida K. and Hirano T.
Advances in Comparative Endocrinology 1291 - 1295 1997年11月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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Uchida K., Kaneko T., Yamaguchi A., Ogasawara T., Hirano T.
Marine Biology 129 ( 2 ) 247 - 253 1997年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Marine Biology
Osmoregulatory ability of mature chum salmon (Oncorhynchus keta) during spawning migration was examined by following the changes in gill Na + , K + -ATPase activity and in the distribution and morphology of chloride cells. Mature chum salmon caught in Otsuchi Bay, northern Honshu Island, Japan, died within 5 d in seawater (SW) in association with a marked increase in plasma osmolality, whereas the fish transferred to fresh water (FW) maintained plasma osmolality efficiently. Gill Na + , K + -ATPase activity decreased in both SW-maintained and FW-transferred fish. Well-developed chloride cells, identified by immunocytochemical staining specific for Na + , K + -ATPase, were present mainly in the filament epithelium of immature fish caught in the ocean. In mature fish caught in the bay, however, additional chloride cells were also founding the lamellar epithelium. The number of filament chloride cells decreased markedly in the mature fish both in SW and in FW, whereas the number of lamellar chloride cells was maintained. These results suggest that the loss of hypo-osmoregulatory ability in mature chum salmon may be attributable to the decrease in filament chloride cells and associated decrease in gill Na + , K + -ATPase activity, and also that appearance of lamellar chloride cells may be preparatory to the forthcoming upstream migration.
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Reduced hypoosmoregulatory ability and alteration in gill chloride cell distribution in mature chum salmon (Oncorhynchus keta) migrating upstream for spawning. 査読あり
Uchida K., Kaneko T., Yamaguchi A., Ogasawara T., Hirano T.
Marine Biology 129 247 - 253 1997年5月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Uchida K., Kaneko T., Yamauchi K., Hirano T.
Journal of Experimental Zoology 276 ( 3 ) 193 - 200 1996年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Experimental Zoology
Changes in gill chloride cell morphology and Na + ,K + -ATPase activity were examined following transfer of chum salmon (Oncorhynchus keta) fry from fresh water (FW) to seawater (SW). The gill Na + ,K + -ATPase activity in chum salmon fry weighing 0.6-3 g had already been increased prior to SW entry, being twice as high as that in late alevin stages (0.3-0.4 g). The activity further increased gradually when the fry (2-3 g) were transferred to SW. Using immunocytochemicaI staining with an antiserum specific for the α- subunit of Na + ,K + -ATPase, chloride cells were detected in both filament and lamellar epithelia in FW fry. The number of chloride cells in the filament was not affected by SW transfer, whereas lamellar chloride cells were significantly decreased. The size of filament chloride cells was 1.8- fold larger than that of FW fish 21 days after SW transfer, whereas there was no change in the size of lamellar chloride cells throughout the experiment. The intensity of immunoreaction gradually increased after transfer to SW in filament chloride cells. Electron-microscopic observations revealed that mitochondria-rich chloride cells were moderately developed in both filaments and lamellae of FW fish. In the SW-adapted fish, well- developed chloride cells were detected only in the filament. These results suggest that chloride cells in the lamella may be the site of ion uptake in FW chum salmon fry and that the well-developed chloride cells in the filament are responsible for salt secretion in SW. The rich population of filament chloride cells, concomitant with enhanced gill Na + ,K + -ATPase activity, may explain the strong seawater adaptability in chum salmon fry prior to SW entry.
DOI： 10.1002/(SICI)1097-010X(19961015)276:3<193::AID-JEZ3>3.0.CO;2-I
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Enhanced chloride cell turnover in the gills of chum salmon fry in seawater
Uchida K., Kaneko T.
Zoological Science 13 ( 5 ) 655 - 660 1996年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zoological Science
Cellular differentiation and renewal in the gill chloride cells were examined in freshwater (FW)- and seawater (SW)-adapted chum salmon (Oncorhynchus keta) fry and in fry during SW adaptation using 5-bromo-2′-deoxyuridine (BrdU) as a marker for newly-differentiated cells. Chloride cells and BrdU-labeled nuclei were immunocytochemically detected by using antisera specific for Na + ,K + -ATPase and BrdU, respectively. Although the number of chloride cells located at the base of the lamellae and in the interlamellar region (filament chloride cells) was constant in FW, SW and SW-transferred groups, chloride cells located in the lamellar epithelium (lamellar chloride cells) were fewer in SW than in FW, and decreased during SW adaptation. Newly-differentiated cells with BrdU-immunoreactive nuclei were detected mainly in the filaments, and rarely observed in the lamellae. The turnover rates of filament chloride cells for FW, SW and SW-transferred fish during the first 24 hr were 8%, 21% and 28%, respectively. These results indicate that chloride cells in the filament are replaced continuously by newly-differentiated cells in both FW and SW, and that the turnover was about 3 times greater in SW than in FW. More frequent turnover of filament chloride cells in SW suggests a specific role, presumably in salt excretion.
DOI： 10.2108/zsj.13.655
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Morphometrical analysis of chloride cell activity in the gill filament and lamellae and changes in gill Na+, K+-ATPase activity during seawater adaptation in chum salmon fry. 査読あり
Uchida K., Kaneko T., Yamauchi K., Hirano T.
Journal of Experimental Zoology 276 193 - 200 1996年6月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Enhanced chloride cell turn over in the gills of chum salmon fry. 査読あり
Uchida K. and Kaneko T.
Zoological Science 13 655 - 660 1996年5月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Levels of calcium in the skin of some amphibians and possible evolutionary implications
Uchida K., Ohtani Y., Sasayama Y., Nambu H., Yoshizawa H., Akabane S., Suzuki K., Suzuki N.
Zoological Science 10 ( 5 ) 819 - 826 1993年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zoological Science
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Detection of calcitonin mRNA in the ultimobranchial gland of the Japanese char with in situ hybridization method.
Uchida K., Yamada H., Suzuki N., Sasayama Y., Nishizawa T.
Progress in Comparative Endocrinology 41 - 42 1993年9月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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Levels of calcium in the skin of some amphibians and possible evolutionary implication. 査読あり
Uchida K., Ohotani Y., Sasayama Y., Nambu H., Yoshizawa H., Akabane S., Suzuki K., Suzuki N.
Zoological Science 10 819 - 826 1993年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）