Histological observation of the pituitary-thyroid axis of a neotenic fish (the ice fish, <Emphasis Type="Italic">Salangichthys microdon</Emphasis>)     

Yasuko?HaradaEmail author  Katsushi?Kuwamura  Izumi?Kinoshita  Masaru?Tanaka  Masatomo?Tagawa 《Fisheries Science》2005,71(1):115-121

ABSTRACT:   In order to study the physiological characteristics of neoteny in teleosts, the development of the thyroid axis and digestive tract of the ice fish, Salangichthys microdon (Salmonoidei), were examined using wild caught samples in the Yura River and its estuary. In all developmental stages examined in this study, the digestive tract was straight, and no gastric gland was observed, even in adults. Since these features are only observed in larval stages of a related species, ayu, Plecoglossus altivelis (Salmonoidei), it is suggested that the ice fish retains larval features, not only in appearance but also in internal organs. Additionally, the thyroid axis exhibited a unique characteristic. Until the end of the juvenile stage, thyroid glands remained inactive, and no thyroid stimulating hormone (TSH) cells were observed. Activation of the thyroid gland and the first appearance of TSH cells occurred in adults. Since activation of the thyroid axis was generally known to occur by the time larval have transformed to juveniles in several teleosts, a delayed functioning of the thyroid axis was suggested as a specific characteristic, and probably a major factor contributing to neotenic development of the ice fish.  相似文献   

Growth of larval and early juvenile Japanese anchovy, Engraulis japonicus, in the Kuroshio-Oyashio transition region     

M. Takahashi  Y. Watanabe  T. Kinoshita  & C. Watanabe 《Fisheries Oceanography》2001,10(2):235-247

Larvae, juveniles, and adults of Japanese anchovy, Engraulis japonicus , were distributed throughout the Kuroshio-Oyashio transition region off northern Japan as far offshore as 170°E in 1996 and 1997. The growth trajectories of individual larvae and early juveniles were backcalculated using the biological intercept method based on the allometric relationship between otolith radius and somatic length. Mean larval growth rates ranged from 0.49 to 0.71 mm day^–1 in the transition region, and were comparable to those reported from the Pacific coastal waters of central Japan, which is the principal distribution range of E. japonicus . In terms of growth, the Kuroshio-Oyashio transition region seemed to be a favourable nursery area for larval E. japonicus . Larval growth tended to decline from the inshore to the offshore waters in the transition region. Thermal conditions did not show an inshore–offshore trend in the survey area and did not explain the longitudinal trend in growth rates.  相似文献   

Assemblages of vertical migratory mesopelagic fish in the transitional region of the western North Pacific   总被引：5，自引：0，他引：5  

Chiyuki Sassa †  Kouichi Kawaguchi  Takahiro Kinoshita  & Chikako Watanabe 《Fisheries Oceanography》2002,11(4):193-204

Assemblages of vertical migratory mesopelagic fish are described for the nighttime upper 20 m layer of the transitional and adjacent waters in the western North Pacific. Twenty-three mesopelagic fish species belonging to six families and 16 genera were collected during June 1996. Family Myctophidae was most speciose, represented by 17 species, followed by Sternoptychidae (two spp.) and Bathylagidae (one spp.). Six assemblages are recognized based on their species composition: Subarctic, Northern Transition, Southern Transition, Subtropical, Slope Water and Seamount Assemblages. These assemblages are also characterized by size composition and biomass of the catches. The distributions of the Subarctic, Northern Transition, Southern Transition and Subtropical Assemblages are approximately defined by the Kuroshio and Oyashio fronts and the Subarctic Boundary. Slope Water and Seamount Assemblages are closely related to the slope water around the shelf edge off Japan and waters around the Shatsky Rise and the Emperor Seamount chain, respectively. The importance of the Southern Transition Assemblage area between the Kuroshio front and Subarctic Boundary as spawning and nursery grounds of many subarctic, transitional and subtropical fishes is elucidated, based on the geographical distribution patterns of their larvae and juveniles.  相似文献   

Preventive effect of Kaempferia parviflora ethyl acetate extract and its major components polymethoxyflavonoid on metabolic diseases     

Shimada T  Horikawa T  Ikeya Y  Matsuo H  Kinoshita K  Taguchi T  Ichinose K  Takahashi K  Aburada M 《Fitoterapia》2011,82(8):1272-1278

Previously, we reported that rhizome powder of Kaempferia parviflora Wall. Ex. Baker prevented obesity and a range of metabolic diseases. In this study, to clarify which molecular mechanisms and active ingredients of K. parviflora have an anti-obesity effect, we investigated the effect of ethyl acetate extract of K. parviflora (KPE) on TSOD mice, a spontaneously obese Type II diabetes model, and on pancreatic lipase. In the TSOD groups, KPE showed a suppressive effect on body weight increase and visceral fat accumulation and also showed preventive effects on symptoms related to insulin resistance, hypertension and fatty liver. In addition, KPE also suppressed body weight increase and food intake in TSNO mice groups, which served as reference animals, at an early stage of administration. Searching for the ingredients in KPE revealed that KPE contains at least 12 kinds of polymethoxyflavonoid (PMF). Furthermore, KPE and its component PMFs showed an inhibitory effect on pancreatic lipase. The above results suggest that KPE has a preventive effect on obesity and various metabolic diseases. The mechanisms of action probably involve inhibition of pancreatic lipase by the PMFs in KPE.  相似文献   

Fertilisation of bovine oocytes by the injection of immobilised, killed spermatozoa   总被引：1，自引：0，他引：1  

K Goto  A Kinoshita  Y Takuma  K Ogawa 《The Veterinary record》1990,127(21):517-520

Immobilised (killed) bovine spermatozoa were microinjected into bovine oocytes matured in vitro and cultured for six to nine days in vitro. A co-culture system with cumulus cells was used for the embryonic development. After one to two, three to four, five to six and seven to eight days the proportions of the oocytes which had developed to the two to four-cell, six to 12-cell, morula and blastocyst stages were 12.0 per cent (61 of 507), 9.3 per cent (47 of 507), 5.9 per cent (30 of 507) and 7.8 per cent (nine of 115), respectively. In contrast, none of the sham-operated group developed beyond the six-cell stage. This is the first report to show that bovine oocytes matured in vitro can undergo cleavage to the blastocyst stage after the injection of sperm in vitro. In addition, normal calves were obtained from the transfers of some of the embryos to recipient cows.  相似文献   

Colitis associated with Clostridium difficile in specific-pathogen-free C3H-scid mice     

Kawano A  Ikeda M  Iritani R  Kinoshita A  Watanabe K  Hayao T  Kokubo T  Matsushita S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(9):973-975

Soft feces and a decreased delivery rate were observed in a specific-pathogen-free (SPF) C3H-scid mouse breeding colony. Grossly, the ceca were shrunken and edematous in the affected mice. Histopathologically, severe edema in the cecal submucosa as well as infiltration of inflammatory cells in the lamina propria and submucosa of the ceca and colon were observed. No pathogenic microorganisms were detected by the routine microbiological tests. By anaerobic bacterial-examination, Clostridium (C.) difficile with toxin A was isolated from the cecal contents of the affected mice. The mice were diagnosed with C. difficile-associated colitis. This case appears to be the first report of natural infection with C. difficile in SPF mice with clinical signs.  相似文献   

Science weathers economic storm     

Kinoshita J 《Science (New York, N.Y.)》1994,266(5188):1170-1173

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Spatio-temporal analysis of yield and weather data for defining site-specific crop management zones     

Kinoshita  Rintaro  Rossiter  David  van Es  Harold 《Precision Agriculture》2021,22(6):1952-1972

Precision Agriculture - Understanding yield potential and yield-limiting factors is essential for improving profitability and grain yields while avoiding adverse environmental effects. In the USA,...  相似文献   

Isolation and characterization of an attenuated strain of an Orthotospovirus,melon yellow spot virus     

Shimomoto  Yoshifumi  Ishikawa  Koichi  Okada  Tomoyuki  Oki  Tomoka  Hayashi  Kazusa  Yano  Kazutaka  Morita  Yasuaki  Takeuchi  Shigeharu 《Journal of General Plant Pathology》2021,87(5):300-306

Journal of General Plant Pathology - An attenuated mutant strain of melon yellow spot virus (MYSV), an Orthotospovirus, designated as SA08-8, was obtained from a pathogenic isolate, C95S, via high...  相似文献   

Thioacetamide-induced Hepatocellular Necrosis Is Attenuated in Diet-induced Obese Mice     

Makoto Shirai  Shingo Arakawa  Hiroaki Miida  Takuya Matsuyama  Junzo Kinoshita  Toshihiko Makino  Kiyonori Kai  Munehiro Teranishi 《Journal of toxicologic pathology》2013,26(2):175-186

To assess modification of thioacetamide-induced hepatotoxicity in mice fed a high-fat diet, male C57BL/6J mice were fed a normal rodent diet or a high-fat diet for 8 weeks and then treated once intraperitoneally with thioacetamide at 50 mg/kg body weight. At 24 and 48 hours after administration, massive centrilobular hepatocellular necrosis was observed in mice fed the normal rodent diet, while the necrosis was less severe in mice fed the high-fat diet. In contrast, severe swelling of hepatocytes was observed in mice fed the high-fat diet. In addition, mice fed the high-fat diet displayed more than a 4-fold higher number of BrdU-positive hepatocytes compared with mice fed the normal rodent diet at 48 hours after thioacetamide treatment. To clarify the mechanisms by which the hepatic necrosis was attenuated, we investigated exposure to thioacetamide and one of its metabolites, the expression of CYP2E1, which converts thioacetamide to reactive metabolites, and the content of glutathione S-transferases in the liver. However, the reduced hepatocellular necrosis noted in mice fed the high-fat diet could not be explained by the differences in exposure to thioacetamide or thioacetamide sulfoxide or by differences in the expression of drug-metabolizing enzymes. On the other hand, at 8 hours after thioacetamide administration, hepatic total glutathione in mice fed the high-fat diet was significantly lower than that in mice fed the normal diet. Hence, decreased hepatic glutathione amount is a candidate for the mechanism of the attenuated necrosis. In conclusion, this study revealed that thioacetamide-induced hepatic necrosis was attenuated in mice fed the high-fat diet.  相似文献