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991.
Rui?HatakeyamaEmail author Norio?Shirafuji Daisuke?Nishimura Tomohiko?Kawamura Yoshiro?Watanabe 《Fisheries Science》2005,71(6):1201-1208
ABSTRACT: The gonad of Spratelloides gracilis was not sexually differentiated in the yolk-sac, preflexion, flexion and postflexion stages. Sexual differentiation and development of the ovary and testis started in the transition stage from larva to juvenile. In juveniles at the fin ray completion stage, the ovary and testis could be distinguished because the ovary contained germ cells initiating meiosis and the testis had blood vessels and a high density of somatic cells. The ovary further developed in larger juveniles to have oocytes of perinucleolus stage together with those of the chromatin nucleolus stage, and oogonium. However, in the testis of larger juveniles, primary spermatogonium began proliferation by meiosis. Sexual differentiation may be regarded as one of morphological and functional changes accompanying metamorphosis in S. gracilis . Some fish larger than the mature size of 60 mm standard length had advanced germ cells and functional gonads, others did not have functional gonads. The distal end of the immature gonads did not connect with a genital duct near the anus. These observations indicate that S. gracilis has large variability in size-at-maturity. The variability in size-at-maturity in S. gracilis , together with large variability in age-at-maturity, may constitute an ecological basis for an extended spawning season in S. gracilis . 相似文献
992.
Laboratory experiments were conducted to examine the shelter effects of turfs of articulated coralline algae (ACA) for the Japanese spiny turban snail Turbo cornutus. The muricid gastropod Ergalatax contractus and the cockerel wrasse Pteragogus flagellifer were used as predators. When the muricid snail was used as a predator, the existence of ACA fronds improved the survival rate of the turban snail juveniles compared with the experimental treatment without ACA fronds. Refuge provided by ACA fronds against predation by the muricid snail was more notable for smaller-sized turban snail juveniles (5.8 mm in shell height) than those of a larger size (8.6 mm in shell height). In the experiment using the wrasse as a predator, a shelter effect was demonstrated for turban snail juveniles of two size groups (4.3 and 10.2 mm in shell height). ACA turfs hindered foraging by the wrasse, so the survival rate of the juveniles was greatly increased. No clear difference was observed between the two size groups of the turban snail in terms of the shelter effect of ACA turf. The shelter effect of ACA turfs for turban snail juveniles is thought to derive from the physical characteristics of the algae, which form a visual and physical barrier. 相似文献
993.
Takauji SR Watanabe M Uyama R Nakagawa T Miyajima N Mochizuki M Nishimura R Sugano S Sasaki N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(8):831-834
Protein expression and subcellular localization of E-cadherin, alpha-catenin, and beta-catenin in 8 feline mammary tumor cell lines were examined by western blot analysis and fluorescence immunocytochemistry. A low E-cadherin expression was observed in FNN-m cells. Furthermore, compared to other cell lines, two E-cadherin bands existed in FMC-p1 cells and were localized in the perinuclear region; distinct radial lines were observed in the cytoplasm. A low alpha-catenin expression was observed in FON-m cells, but there were no apparent abnormalities in its localization. In contrast, similar levels of beta-catenin expression and cytoplasmic localization were observed in all cell lines. 相似文献
994.
995.
Rikako Ishigamori Mie Naruse Akihiro Hirata Yoshiaki Maru Yoshitaka Hippo Toshio Imai 《Journal of toxicologic pathology》2022,35(3):211
Recently, we introduced an organoid-based chemical carcinogenesis model using mouse normal tissue-derived organoids. In the present review article, the histopathological and immunohistochemical characteristics of mouse normal tissue-derived organoids and tumors derived from these organoids after their in vitro treatment with genotoxic carcinogens and injection into nude mouse are reviewed. In organoids treated in vitro with genotoxic carcinogens, we confirmed macroscopic tumorigenicity and histopathological findings, including neoplastic characteristics, such as multilayered epithelia and/or invasion of epithelia into the surrounding interstitium. In contrast glandular/cystic structures with monolayered epithelia were clearly demarcated from the surrounding Matrigel/interstitium in the untreated control groups. In addition to macroscopic tumorigenicity, these microscopic epithelial changes, which are characteristic of the early stages of carcinogenesis, are included in the requirements for carcinogenicity-positive judgement of the organoid-based carcinogenesis model. Immunohistochemistry of cytokeratins (CKs), used to determine the origin of epithelia and distribution of extraductal invasive lesions, or oncogenic kinases, which reflect molecular activation in epithelia following chemical treatment, is helpful for accurate diagnosis and molecular evaluation in the early stages of carcinogenesis. This information improves our biological understanding of organoid-based chemical carcinogenesis models. 相似文献
996.
Watanabe S Taguchi H Temmei Y Hirao T Akiyama H Sakai S Adachi R Urisu A Teshima R 《Journal of agricultural and food chemistry》2012,60(9):2108-2115
Two PCR methods were developed for specific detection of the trnS-trnG intergenic spacer region of Prunus persica (peach) and the internal transcribed spacer region of Malus domestica (apple). The peach PCR amplified a target-size product from the DNA of 6 P. persica cultivars including 2 nectarine and 1 flat peach cultivar, but not from those of 36 nontarget species including 6 Prunus and 5 other Rosaceae species. The apple PCR amplified a target-size product from the DNA of 5 M. domestica cultivars, but not from those of 41 nontarget species including 7 Maloideae and 9 other Rosaceae species. Both methods detected the target DNA from strawberry jam and cookies spiked with peach and apple at a level equivalent to about 10 μg of total soluble proteins of peach or apple per gram of incurred food. The specificity and sensitivity were considered to be sufficient for the detection of trace amounts of peach or apple contamination in processed foods. 相似文献
997.
Kawamura-Konishi Y Watanabe N Saito M Nakajima N Sakaki T Katayama T Enomoto T 《Journal of agricultural and food chemistry》2012,60(22):5565-5570
Ethanol extracts from 15 kinds of marine algae collected from the coast of the Noto Peninsula in Japan were examined for their inhibitory effects on human salivary α-amylase. Four extracts significantly suppressed the enzyme activity. An inhibitor was purified from the extract of Sargassum patens . The compound was a new phloroglucinol derivative, 2-(4-(3,5-dihydroxyphenoxy)-3,5-dihydroxyphenoxy) benzene-1,3,5-triol (DDBT), which strongly suppressed the hydrolysis of amylopectin by human salivary and pancreatic α-amylases. The 50% inhibitory activity (IC(50)) for α-amylase inhibition of DDBT (3.2 μg/mL) was much lower than that of commercially available α-amylase inhibitors, acarbose (26.3 μg/mL), quercetagetin (764 μg/mL), and α-amylase inhibitor from Triticum aestivum (88.3 μg/mL). A kinetic study indicated that DDBT was a competitive α-amylase inhibitor with a K(i) of 1.8 μg/mL. DDBT also inhibited rat intestinal α-glucosidase with an IC(50) value of 25.4 μg/mL for sucrase activity and 114 μg/mL for maltase activity. These results suggest that DDBT, a potent inhibitor of carbohydrate-hydrolyzing enzymes, may be useful as a natural nutraceutical to prevent diabetes. 相似文献
998.
Yasutomo Hoshika Makoto Watanabe Naoki Inada Takayoshi Koike 《Water, air, and soil pollution》2012,223(8):5017-5025
We examined the effects of ozone and elevated CO2 concentration in summer on the growth and photosynthetic traits of three representative birch species in Japan (mountain birch, Monarch birch, and white birch). Seedlings of the three birch species were grown in 16 open-top chambers and were exposed to two levels of ozone (6 and 60?nmol?mol?1 for 7?h per day) in combination with two levels of CO2 (370?C380 and 600???mol?mol?1 for daytime) from July to October. No adverse effects of ozone were found in the Monarch birch or the white birch, but elevated ozone in summer reduced branch biomass and net photosynthesis, and accelerated leaf abscission, in the mountain birch. Elevated CO2 promoted root development and thereby reduced the ratio of shoot dry mass (stem + branch) to root dry mass (S/R ratio) in the mountain birch and white birch. In contrast, there was no difference in dry mass between ambient and elevated CO2 for the Monarch birch, due to downregulation of photosynthesis. Studies of the combined effect of CO2 and ozone revealed that elevated CO2 did not ameliorate the effect of ozone on mountain birch in late summer. In considering the ameliorating effect of CO2 on ozone damage, it is necessary to take account of the species and the season. 相似文献
999.
Tatsuhiko Suzuki Yoshiharu Tokunaga Iwao Watanabe 《Soil Science and Plant Nutrition》2013,59(6):280-291
It is well known that tillage of soil produces greater aeration and incorporates crop residues and fertilizers into inner soil layers, thus stimulating the microbial activities and increasing the rate of decomposition of soil organic matter. Tillage operation has been, therefore, one of the important practices to increase soil productivity. 相似文献
1000.
Amnat Chidthaisong Kazuyuki Inubushi Iwao Watanabe 《Soil Science and Plant Nutrition》2013,59(3):645-649
Extract It was reported that flooded rice soil was an important source of atmospheric CH4 (Cicerone and Shetter 1981; Sciler et al. 1984). In flooded rice soils, CH4 is produced under strict anaerobic conditions by methanogenic bacteria (Jones et al. 1987; Jones 1991). Rice plants carry the produced CH4 from anoxic sediment and release it to the atmosphere (Cicerone and Shetter 1981; Nouchi et al. 1990). More than 90% of emitted CH4 is released through rice plants and the emission pattern usually shows large seasonal variations (Cicerone et al. 1983; Sciler et al. 1984; Inubushi et al. 1989). Since the number of methanogens did not change throughout the rice growth season (Schutz et al. 1989; Mayer and Conrad 1990), seasonal variations of CH4 emission could be ascribed to the activities of methanogens and the amount of available substrates. However, the changes in the methanogenic activities in response to available substrates especially in relation to the growth period of rice plants are poorly documented. 相似文献