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Seiji Ohsumi - One of the best experts on this subject based on the ideXlab platform.
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SC/D06/J26 What has happened to the Antarctic Minke Whale Stocks?
2016Co-Authors: Yoshihiro Fujise, Hiroshi Hatanaka, Seiji OhsumiAbstract:Historical changes in the Antarctic Minke Whale stocks were examined based on various results obtained from JARPA including age at sexual maturity, growth curve, blubber thickness, prey consumption, and ADAPT-VPA analysis of the stocks as well as research on mercury accumulation etc. It has been assumed that feeding conditions of the Minke Whale improved with the removal of large baleen Whales such as the blue Whale by commercial whaling, which promoted rapid growth and younger age at sexual maturity; however, around 1970, conditions gradually shifted unfavourably, resulting in slower rates of change in the foregoing parameters. These changes were then arrested by the 1980s to the 1990s. Reflecting these unfavourable changes, it was observed that blubber thickness and stomach content weight were reduced, which indicated less prey consumption. There was also a decrease in the accumulation of mercury resulting from less prey consumption. Also, the distribution area of humpback and fin Whales in the feeding season expanded southward in the Antarctic from around 1990, suggesting further deterioration of feeding conditions for the Antarctic Minke Whales
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areolae of the placenta in the antarctic Minke Whale balaenoptera bonaerensis
Journal of Reproduction and Development, 2014Co-Authors: Hajime Ishikawa, Seiji Ohsumi, Motoki Sasaki, Yoko Amano, Daisuke Hayakawa, Toshio Tsubota, Toshihiro Mogoe, Masafumi TetsukaAbstract:In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic Minke Whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections. The opening of the areolar cavity was hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like structure lined by tall columnar cells similar to areolar trophoblast cells within the stroma of chorionic villi was noticed and continued to the areolar cavity, with the opening seen on serial sections. In a surface investigation of the chorion and endometrium by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli attached with many blebs from trophoblast cells. In our immunohistochemical observations, a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells showed weak or no immunoreactivity for P450scc.
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Structure and steroidogenesis of the placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis).
The Journal of reproduction and development, 2012Co-Authors: Motoki Sasaki, Hajime Ishikawa, Seiji Ohsumi, Yoko Amano, Daisuke Hayakawa, Toshio Tsubota, Toshihiro Mogoe, Masafumi Tetsuka, Akio Miyamoto, Yutaka FukuiAbstract:There are few reports describing the structure and function of the Whale placenta with the advance of pregnancy. In this study, therefore, the placenta and nonpregnant uterus of the Antarctic Minke Whale were observed morphologically and immunohistochemically. Placentas and nonpregnant uteri were collected from the 15th, 16th and 18th Japanese Whale Research Programme with Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. In the macro- and microscopic observations, the placenta of the Antarctic Minke Whale was a diffuse and epitheliochorial placenta. The chorion was interdigitated to the endometrium by primary, secondary and tertiary villi, which contained no specialized trophoblast cells such as binucleate cells, and the interdigitation became complicated with the progress of gestation. Furthermore, fetal and maternal blood vessels indented deeply into the trophoblast cells and endometrial epithelium respectively with fetal growth. The Minke Whale placenta showed a fold-like shape as opposed to a finger-like shape. In both nonpregnant and pregnant uteri, many uterine glands were distributed. The uterine glands in the superficial layer of the pregnant endometrium had a wide lumen and large epithelial cells as compared with those in the deep layer. On the other hand, in the nonpregnant endometrium, the uterine glands had a narrower lumen and smaller epithelial cells than in the pregnant endometrium. In immunohistochemical detection, immunoreactivity for P450scc was detected in most trophoblast cells, but not in nonpregnant uteri, suggesting that trophoblast epithelial cells synthesized and secreted the sex steroid hormones and/or their precursors to maintain the pregnancy in the Antarctic Minke Whale.
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attempt at in vitro maturation of Minke Whale balaenoptera bonaerensis oocytes using a portable co2 incubator
Journal of Reproduction and Development, 2005Co-Authors: Hiroshi Iwayama, Hajime Ishikawa, Seiji Ohsumi, Yutaka FukuiAbstract:The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and Minke Whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17β (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for Minke Whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In Minke Whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture. Moreover, the IVM culture period was shortened to 28-30 h from 96-120 h previously reported. The proportion of matured oocytes cultured in the medium supplemented with pFSH/E2 (26.7%) was significantly higher (P<0.05) than that with PMSG/hCG (6.9%). The present study indicates that a portable CO2 incubator is a useful device for Minke Whale IVM culture on a research base ship, and the addition of pFSH/E2 into an IVM medium enhanced cumulus expansion and the proportion of Minke Whale matured oocytes.
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Attempt at in vitro maturation of Minke Whale (Balaenoptera Bonaerensis) oocytes using a portable CO2 incubator.
The Journal of reproduction and development, 2005Co-Authors: Hiroshi Iwayama, Hajime Ishikawa, Seiji Ohsumi, Yutaka FukuiAbstract:The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and Minke Whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17β (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for Minke Whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In Minke Whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture. Moreover, the IVM culture period was shortened to 28-30 h from 96-120 h previously reported. The proportion of matured oocytes cultured in the medium supplemented with pFSH/E2 (26.7%) was significantly higher (P
Yutaka Fukui - One of the best experts on this subject based on the ideXlab platform.
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Structure and steroidogenesis of the placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis).
The Journal of reproduction and development, 2012Co-Authors: Motoki Sasaki, Hajime Ishikawa, Seiji Ohsumi, Yoko Amano, Daisuke Hayakawa, Toshio Tsubota, Toshihiro Mogoe, Masafumi Tetsuka, Akio Miyamoto, Yutaka FukuiAbstract:There are few reports describing the structure and function of the Whale placenta with the advance of pregnancy. In this study, therefore, the placenta and nonpregnant uterus of the Antarctic Minke Whale were observed morphologically and immunohistochemically. Placentas and nonpregnant uteri were collected from the 15th, 16th and 18th Japanese Whale Research Programme with Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. In the macro- and microscopic observations, the placenta of the Antarctic Minke Whale was a diffuse and epitheliochorial placenta. The chorion was interdigitated to the endometrium by primary, secondary and tertiary villi, which contained no specialized trophoblast cells such as binucleate cells, and the interdigitation became complicated with the progress of gestation. Furthermore, fetal and maternal blood vessels indented deeply into the trophoblast cells and endometrial epithelium respectively with fetal growth. The Minke Whale placenta showed a fold-like shape as opposed to a finger-like shape. In both nonpregnant and pregnant uteri, many uterine glands were distributed. The uterine glands in the superficial layer of the pregnant endometrium had a wide lumen and large epithelial cells as compared with those in the deep layer. On the other hand, in the nonpregnant endometrium, the uterine glands had a narrower lumen and smaller epithelial cells than in the pregnant endometrium. In immunohistochemical detection, immunoreactivity for P450scc was detected in most trophoblast cells, but not in nonpregnant uteri, suggesting that trophoblast epithelial cells synthesized and secreted the sex steroid hormones and/or their precursors to maintain the pregnancy in the Antarctic Minke Whale.
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contribution of spermatozoal centrosomes to the microtubule organizing centre in antarctic Minke Whale balaenoptera bonaerensis
Zygote, 2006Co-Authors: Toshihiro Kobayashi, Hajime Ishikawa, Yutaka Fukui, Kazue Amemiya, Kana Takeuchi, Tomomi Tsujioka, Keiichiro Tominaga, Masumi Hirabayashi, Shinichi HochiAbstract:Using an interspecies microinsemination assay with bovine oocytes, it was examined whether centrosomes of Antarctic Minke Whale spermatozoa function as the microtubule-organizing centre (MTOC). Bull and rat spermatozoa were used as positive and negative controls, respectively. Vitrified-warmed bovine mature oocytes were subjected to immunostaining against alpha-tubulin 4-6 h after intracytoplasmic injection (ICSI) of 5 mM dithiothreitol-treated spermatozoa. Aster formation occurred from Whale spermatozoa (33%) and bull spermatozoa (33%), but very little from rat spermatozoa (3%). Activation treatment for the microinseminated oocytes with 7% ethanol + 2 mM 6-dimethylaminopurine resulted in a similar proportion of oocytes forming a Whale sperm aster (35% vs 27% in the non-treated group; 4 h after ICSI) but a significantly larger aster (ratio of aster diameter to oocyte diameter, 0.57 vs 0.30 in the non-treated group). These results indicate that the centrosome introduced into bovine oocytes by Whale spermatozoa contributes to the MTOC and that assembly of the microtubule network is promoted by oocyte activation.
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attempt at in vitro maturation of Minke Whale balaenoptera bonaerensis oocytes using a portable co2 incubator
Journal of Reproduction and Development, 2005Co-Authors: Hiroshi Iwayama, Hajime Ishikawa, Seiji Ohsumi, Yutaka FukuiAbstract:The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and Minke Whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17β (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for Minke Whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In Minke Whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture. Moreover, the IVM culture period was shortened to 28-30 h from 96-120 h previously reported. The proportion of matured oocytes cultured in the medium supplemented with pFSH/E2 (26.7%) was significantly higher (P<0.05) than that with PMSG/hCG (6.9%). The present study indicates that a portable CO2 incubator is a useful device for Minke Whale IVM culture on a research base ship, and the addition of pFSH/E2 into an IVM medium enhanced cumulus expansion and the proportion of Minke Whale matured oocytes.
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Attempt at in vitro maturation of Minke Whale (Balaenoptera Bonaerensis) oocytes using a portable CO2 incubator.
The Journal of reproduction and development, 2005Co-Authors: Hiroshi Iwayama, Hajime Ishikawa, Seiji Ohsumi, Yutaka FukuiAbstract:The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and Minke Whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17β (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for Minke Whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In Minke Whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture. Moreover, the IVM culture period was shortened to 28-30 h from 96-120 h previously reported. The proportion of matured oocytes cultured in the medium supplemented with pFSH/E2 (26.7%) was significantly higher (P
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effects of cryodevice type and donors sexual maturity on vitrification of Minke Whale balaenoptera bonaerensis oocytes at germinal vesicle stage
Zygote, 2004Co-Authors: Hiroshi Iwayama, Hajime Ishikawa, Seiji Ohsumi, Masumi Hirabayashi, Shinichi Hochi, Megumi Kato, Masashige Kuwayama, Yutaka FukuiAbstract:Summary Germinal-vesicle-stage oocytes enclosed with compact cumulus cell layers (COCs) were recovered from adult or prepubertal Minke Whale ovaries, and were vitrified in a solution containing 15% ethylene glycol, 15% DMSO and 0.5 M sucrose using either a Cryotop or an open-pulled straw (OPS) as the cryodevice. The post-warm COCs with normal morphology were cultured for 40 h in a 390 mosmol in vitro maturation medium, and oocytes extruding the first polar body were considered to be matured. The proportion of morphologically normal COCs after vitrification and warming was higher when the COCs were cryopreserved by Cryotop (adult origin, 88.4%; prepubertal origin, 80.8%) compared with the OPS (adult origin, 67.7%; prepubertal origin, 64.2%). The oocyte maturation rate was higher in the adult/Cryotop group (29.1%) compared with those of the prepubertal/Cryotop group (14.4%), the adult/OPS group (14.3%) and the prepubertal/OPS group (10.6%). These results indicate that the Cryotop is a better device than the OPS for vitrification of immature oocytes from adult Minke Whales.
Hajime Ishikawa - One of the best experts on this subject based on the ideXlab platform.
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areolae of the placenta in the antarctic Minke Whale balaenoptera bonaerensis
Journal of Reproduction and Development, 2014Co-Authors: Hajime Ishikawa, Seiji Ohsumi, Motoki Sasaki, Yoko Amano, Daisuke Hayakawa, Toshio Tsubota, Toshihiro Mogoe, Masafumi TetsukaAbstract:In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic Minke Whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections. The opening of the areolar cavity was hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like structure lined by tall columnar cells similar to areolar trophoblast cells within the stroma of chorionic villi was noticed and continued to the areolar cavity, with the opening seen on serial sections. In a surface investigation of the chorion and endometrium by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli attached with many blebs from trophoblast cells. In our immunohistochemical observations, a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells showed weak or no immunoreactivity for P450scc.
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Structure and steroidogenesis of the placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis).
The Journal of reproduction and development, 2012Co-Authors: Motoki Sasaki, Hajime Ishikawa, Seiji Ohsumi, Yoko Amano, Daisuke Hayakawa, Toshio Tsubota, Toshihiro Mogoe, Masafumi Tetsuka, Akio Miyamoto, Yutaka FukuiAbstract:There are few reports describing the structure and function of the Whale placenta with the advance of pregnancy. In this study, therefore, the placenta and nonpregnant uterus of the Antarctic Minke Whale were observed morphologically and immunohistochemically. Placentas and nonpregnant uteri were collected from the 15th, 16th and 18th Japanese Whale Research Programme with Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. In the macro- and microscopic observations, the placenta of the Antarctic Minke Whale was a diffuse and epitheliochorial placenta. The chorion was interdigitated to the endometrium by primary, secondary and tertiary villi, which contained no specialized trophoblast cells such as binucleate cells, and the interdigitation became complicated with the progress of gestation. Furthermore, fetal and maternal blood vessels indented deeply into the trophoblast cells and endometrial epithelium respectively with fetal growth. The Minke Whale placenta showed a fold-like shape as opposed to a finger-like shape. In both nonpregnant and pregnant uteri, many uterine glands were distributed. The uterine glands in the superficial layer of the pregnant endometrium had a wide lumen and large epithelial cells as compared with those in the deep layer. On the other hand, in the nonpregnant endometrium, the uterine glands had a narrower lumen and smaller epithelial cells than in the pregnant endometrium. In immunohistochemical detection, immunoreactivity for P450scc was detected in most trophoblast cells, but not in nonpregnant uteri, suggesting that trophoblast epithelial cells synthesized and secreted the sex steroid hormones and/or their precursors to maintain the pregnancy in the Antarctic Minke Whale.
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contribution of spermatozoal centrosomes to the microtubule organizing centre in antarctic Minke Whale balaenoptera bonaerensis
Zygote, 2006Co-Authors: Toshihiro Kobayashi, Hajime Ishikawa, Yutaka Fukui, Kazue Amemiya, Kana Takeuchi, Tomomi Tsujioka, Keiichiro Tominaga, Masumi Hirabayashi, Shinichi HochiAbstract:Using an interspecies microinsemination assay with bovine oocytes, it was examined whether centrosomes of Antarctic Minke Whale spermatozoa function as the microtubule-organizing centre (MTOC). Bull and rat spermatozoa were used as positive and negative controls, respectively. Vitrified-warmed bovine mature oocytes were subjected to immunostaining against alpha-tubulin 4-6 h after intracytoplasmic injection (ICSI) of 5 mM dithiothreitol-treated spermatozoa. Aster formation occurred from Whale spermatozoa (33%) and bull spermatozoa (33%), but very little from rat spermatozoa (3%). Activation treatment for the microinseminated oocytes with 7% ethanol + 2 mM 6-dimethylaminopurine resulted in a similar proportion of oocytes forming a Whale sperm aster (35% vs 27% in the non-treated group; 4 h after ICSI) but a significantly larger aster (ratio of aster diameter to oocyte diameter, 0.57 vs 0.30 in the non-treated group). These results indicate that the centrosome introduced into bovine oocytes by Whale spermatozoa contributes to the MTOC and that assembly of the microtubule network is promoted by oocyte activation.
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attempt at in vitro maturation of Minke Whale balaenoptera bonaerensis oocytes using a portable co2 incubator
Journal of Reproduction and Development, 2005Co-Authors: Hiroshi Iwayama, Hajime Ishikawa, Seiji Ohsumi, Yutaka FukuiAbstract:The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and Minke Whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17β (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for Minke Whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In Minke Whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture. Moreover, the IVM culture period was shortened to 28-30 h from 96-120 h previously reported. The proportion of matured oocytes cultured in the medium supplemented with pFSH/E2 (26.7%) was significantly higher (P<0.05) than that with PMSG/hCG (6.9%). The present study indicates that a portable CO2 incubator is a useful device for Minke Whale IVM culture on a research base ship, and the addition of pFSH/E2 into an IVM medium enhanced cumulus expansion and the proportion of Minke Whale matured oocytes.
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Attempt at in vitro maturation of Minke Whale (Balaenoptera Bonaerensis) oocytes using a portable CO2 incubator.
The Journal of reproduction and development, 2005Co-Authors: Hiroshi Iwayama, Hajime Ishikawa, Seiji Ohsumi, Yutaka FukuiAbstract:The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and Minke Whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17β (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for Minke Whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In Minke Whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture. Moreover, the IVM culture period was shortened to 28-30 h from 96-120 h previously reported. The proportion of matured oocytes cultured in the medium supplemented with pFSH/E2 (26.7%) was significantly higher (P
Toshihiro Mogoe - One of the best experts on this subject based on the ideXlab platform.
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areolae of the placenta in the antarctic Minke Whale balaenoptera bonaerensis
Journal of Reproduction and Development, 2014Co-Authors: Hajime Ishikawa, Seiji Ohsumi, Motoki Sasaki, Yoko Amano, Daisuke Hayakawa, Toshio Tsubota, Toshihiro Mogoe, Masafumi TetsukaAbstract:In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic Minke Whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections. The opening of the areolar cavity was hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like structure lined by tall columnar cells similar to areolar trophoblast cells within the stroma of chorionic villi was noticed and continued to the areolar cavity, with the opening seen on serial sections. In a surface investigation of the chorion and endometrium by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli attached with many blebs from trophoblast cells. In our immunohistochemical observations, a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells showed weak or no immunoreactivity for P450scc.
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Structure and steroidogenesis of the placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis).
The Journal of reproduction and development, 2012Co-Authors: Motoki Sasaki, Hajime Ishikawa, Seiji Ohsumi, Yoko Amano, Daisuke Hayakawa, Toshio Tsubota, Toshihiro Mogoe, Masafumi Tetsuka, Akio Miyamoto, Yutaka FukuiAbstract:There are few reports describing the structure and function of the Whale placenta with the advance of pregnancy. In this study, therefore, the placenta and nonpregnant uterus of the Antarctic Minke Whale were observed morphologically and immunohistochemically. Placentas and nonpregnant uteri were collected from the 15th, 16th and 18th Japanese Whale Research Programme with Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. In the macro- and microscopic observations, the placenta of the Antarctic Minke Whale was a diffuse and epitheliochorial placenta. The chorion was interdigitated to the endometrium by primary, secondary and tertiary villi, which contained no specialized trophoblast cells such as binucleate cells, and the interdigitation became complicated with the progress of gestation. Furthermore, fetal and maternal blood vessels indented deeply into the trophoblast cells and endometrial epithelium respectively with fetal growth. The Minke Whale placenta showed a fold-like shape as opposed to a finger-like shape. In both nonpregnant and pregnant uteri, many uterine glands were distributed. The uterine glands in the superficial layer of the pregnant endometrium had a wide lumen and large epithelial cells as compared with those in the deep layer. On the other hand, in the nonpregnant endometrium, the uterine glands had a narrower lumen and smaller epithelial cells than in the pregnant endometrium. In immunohistochemical detection, immunoreactivity for P450scc was detected in most trophoblast cells, but not in nonpregnant uteri, suggesting that trophoblast epithelial cells synthesized and secreted the sex steroid hormones and/or their precursors to maintain the pregnancy in the Antarctic Minke Whale.
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The Pattern of Ovarian Development in the Prepubertal Antarctic Minke Whale (Balaenoptera bonaerensis)
The Journal of reproduction and development, 2004Co-Authors: Masafumi Tetsuka, Hajime Ishikawa, Yutaka Fukui, Toshihiro Mogoe, Masatsugu Asada, Seiji OhsumiAbstract:This study describes the morphological and morphometrical changes associated with prepubertal ovarian development in the Antarctic Minke Whale (Balaenoptera bonaerensis). Ovaries were harvested from 94 immature Minke Whales caught in the Antarctic Ocean during the summer feeding season (December-March). Notable differences in ovarian size and morphology were found among animals. Up to 10 folds difference in ovarian weight was found among prepubertal Whales of similar body size. During the prepubertal period, ovaries grew slowly and approximately doubled their weight. The morphologies of right and left ovaries were almost identical while the growth of the ovary appears to occur preferentially on the right side. The most striking morphological feature was numerous small antral follicles less than 5 mm in diameter found in ovaries of younger immature Whales. The occurrence of these ovaries was highest in Whales less than 6 m long and gradually decreased as body length increased. In larger Whales, the occurrence of ovaries with a smaller number of follicles up to 10 mm and thick tunica albuginea increased. Thus, the ovary of the Antarctic Minke Whale experiences bursts of small follicular development during the early prepubertal period before becoming a more developed ovary with fewer but larger follicles, and thick tunica albuginea.
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in vitro maturation and ultrastructural observation of cryopreserved Minke Whale balaenoptera acutorostrata follicular oocytes
Biology of Reproduction, 2000Co-Authors: Masatsugu Asada, Hajime Ishikawa, Yutaka Fukui, Toshihiro Mogoe, Miki Horii, Seiji OhsumiAbstract:Minke Whale (Balaenoptera acutorostrata) follicular oocytes were cryopreserved by a slow-step freezing procedure using ethylene glycol. The morphologically viable proportion of postthawed Minke Whale follicular oocytes was 39.7%. The maturity of the animals (immature and mature Whales) or the presence or absence of cumulus cells (CC) did not affect the proportion of morphologically viable oocytes. Postthawed oocytes were examined for nuclear status after in vitro maturation. The presence of CC (29.1%) significantly enhanced (P < 0.05) the proportion of oocytes at metaphase I/anaphase I/telophase I stages compared to results with the absence of CC (13.5%). A total of 4 of 194 postthawed oocytes matured to the second metaphase stage after culture for 5.5 days with or without CC. The cryopreserved immature oocytes obtained from immature and mature Whales were processed to examine the ultrastructure by transmission electron microscopy. Varying ultrastructural damage to the cytoplasm was observed as a result of the cryopreservation procedures. These results show that 20-30% of cryopreserved Minke Whale follicular oocytes can resume meiosis in vitro, but damage induced by the freezing and thawing procedures was observed.
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in vitro fertilization of in vitro matured Minke Whale balaenoptera acutorostrata follicular oocytes
Marine Mammal Science, 1997Co-Authors: Yutaka Fukui, Hajime Ishikawa, Toshihiro Mogoe, Seiji OhsumiAbstract:In vitro fertilization of follicular oocytes harvested from ovaries and matured in vitro was attempted for 55 Minke Whales (Balaenoptera acutorostrata) captured for Japanese research purposes in the Antarctic Ocean during the period from November 1995 to March 1996. In Experiment 1, effects of culture duration (96 h or 120 h) on maturation of follicular oocytes and addition of caffeine (5 mM) and/or heparin (100 pg/ml) on sperm penetration and pro-nuclear formation were investigated. Spermatozoa recovered from the vasa deferentia of four mature males were diluted (5-fold) and frozen at - 80°C. The post-thawed and pooled spermatozoa were used for in vitro insemination. A higher (P < 0.05) proportion of the oocytes cultured for 120 h (34.2% of 260) progressed beyond the second metaphase stage than of the oocytes cultured for 96 h (26.0% of 262). For the matured oocytes, higher rates of penetration (P < 0.05) and pronuclear formation (P < 0.01) were obtained in the oocytes cultured for 120 h (55.1% and 40.4%) than in those cultured for 96 h (32.4 % and 20.6%). Addition of caffeine and heparin did not show a significant effect. In Experiment 2, follicular oocytes matured for 120 h and then inseminated were cultured to examine the subsequent development in two culture systems (with and without co-cultured cumulus cells). Of 448 inseminated oocytes, cleaved embryos (2–16 cells) were observed with (5.8%) and without (4.9%) co-cultured systems. No cleavage was observed in 54 ova without insemination. These results indicate that in vitro fertilization of Minke Whale in vitro matured follicular oocytes with cryopreserved spermatozoa is possible, yielding cleaved embryos.
Frank E. Fish - One of the best experts on this subject based on the ideXlab platform.
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Hydrodynamic performance of the Minke Whale (Balaenoptera acutorostrata) flipper.
Journal of Experimental Biology, 2008Co-Authors: Lisa Noelle Cooper, Nils Sedano, Stig Johansson, Bryan May, Joey D. Brown, Casey M. Holliday, Brian W. Kot, Frank E. FishAbstract:SUMMARY Minke Whales ( Balaenoptera acutorostrata ) are the smallest member of balaenopterid Whales and little is known of their kinematics during feeding maneuvers. These Whales have narrow and elongated flippers that are small relative to body size compared to related species such as right and gray Whales. No experimental studies have addressed the hydrodynamic properties of Minke Whale flippers and their functional role during feeding maneuvers. This study integrated wind tunnel, locomotion and anatomical range of motion data to identify functional parameters of the cambered Minke Whale flipper. A full-sized cast of a Minke Whale flipper was used in wind tunnel testing of lift, drag and stall behavior at six speeds, corresponding to swimming speeds of 0.7–8.9 m s –1 . Flow over the model surface stalled between 10° and 14° angle of attack (α) depending on testing speed. When the leading edge was rotated ventrally, loss in lift occurred around –18° α regardless of speed. Range of mobility in the fresh limb was approximately 40% greater than the range of positive lift-generating angles of attack predicted by wind tunnel data (+14°α ). Video footage, photographs and observations of swimming, engulfment feeding and gulping Minke Whales showed limb positions corresponding to low drag in wind tunnel tests, and were therefore hydrodynamically efficient. Flippers play an important role in orienting the body during feeding maneuvers as they maintain trim of the body, an action that counters drag-induced torque of the body during water and prey intake.
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Hydrodynamic performance of the Minke Whale (Balaenoptera acutorostrata) flipper.
The Journal of experimental biology, 2008Co-Authors: Lisa Noelle Cooper, Nils Sedano, Stig Johansson, Bryan May, Joey D. Brown, Casey M. Holliday, Brian W. Kot, Frank E. FishAbstract:Minke Whales (Balaenoptera acutorostrata) are the smallest member of balaenopterid Whales and little is known of their kinematics during feeding maneuvers. These Whales have narrow and elongated flippers that are small relative to body size compared to related species such as right and gray Whales. No experimental studies have addressed the hydrodynamic properties of Minke Whale flippers and their functional role during feeding maneuvers. This study integrated wind tunnel, locomotion and anatomical range of motion data to identify functional parameters of the cambered Minke Whale flipper. A full-sized cast of a Minke Whale flipper was used in wind tunnel testing of lift, drag and stall behavior at six speeds, corresponding to swimming speeds of 0.7-8.9 m s(-1). Flow over the model surface stalled between 10 degrees and 14 degrees angle of attack (alpha) depending on testing speed. When the leading edge was rotated ventrally, loss in lift occurred around -18 degrees alpha regardless of speed. Range of mobility in the fresh limb was approximately 40% greater than the range of positive lift-generating angles of attack predicted by wind tunnel data (+14 degrees alpha). Video footage, photographs and observations of swimming, engulfment feeding and gulping Minke Whales showed limb positions corresponding to low drag in wind tunnel tests, and were therefore hydrodynamically efficient. Flippers play an important role in orienting the body during feeding maneuvers as they maintain trim of the body, an action that counters drag-induced torque of the body during water and prey intake.