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11.
Yuji Kominami Mayuko Jomura Mioko Ataka Koji Tamai Takafumi Miyama Masako Dannoura Naoki Makita Kenichi Yoshimura 《Journal of Forest Research》2012,17(3):296-304
To assess the effect of changes in organic litter stock on seasonal changes in heterotrophic respiration (R H), soil respiration (R S), and total ecosystem respiration (R E), we measured seasonal changes in leaf litter respiration (R LL) by the chamber method and estimated the seasonal change in total R H using the RothC model in a warm-temperate mixed deciduous?Cevergreen forest in Japan. Both R E and R S had seasonal hysteresis and were higher in spring than at the same temperature during autumn. Under warm and humid conditions, the rate of decomposition of newly supplied leaf litter in one?year was high (60% loss). Consequently, R LL and R H were higher in spring after leaf drop, when more fresh material was available, than in autumn. In this study, 42 and 88% of the difference in R E and R S between spring and autumn (soil temperature 16?C18°C) could be accounted for by the difference in R H, respectively, and 71% of the difference in R H could be accounted for by the difference in R LL. This study showed that seasonal changes in heterotrophic respiration (R LL and R H) could be a major factor in the seasonal hysteresis of R E and R S. 相似文献
12.
Akihiro Hagiwara Norio Imai Yuko Doi Mayuko Suguro Mayumi Kawabe Fumio Furukawa Kasuke Nagano Shoji Fukushima 《Journal of toxicologic pathology》2013,26(4):351-357
The effects of ethyl tertiary-butyl ether (ETBE) on two-stage urinary bladder carcinogenesis in male F344 rats initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) were investigated at various dose levels with regard to possible promoting activity. Groups of 30 rats were given drinking water containing 500 ppm BBN, as an initiator, for 4 weeks and starting one week thereafter received ETBE by gavage (daily, 7 days/week) at dose levels of 0 (control), 100, 300, 500 or 1000 mg/kg/day until experimental week 36. No statistically significant differences in incidences of preneoplastic lesions, papillomas, and carcinomas of the urinary bladder were evident in rats treated with 100–1000 mg/kg/day ETBE as compared with control values. Furthermore, the average numbers of preneoplastic or neoplastic lesions per unit length of basement membrane in rats given 100–1000 mg/kg/day ETBE were also comparable to control values. However, papillomatosis of the urinary bladder was found in 4 out of 30 rats (13%) in the group given 1000 mg/kg/day ETBE, and soft stones in the urinary bladder were found in 3 out of these 4 rats. The results thus demonstrated that ETBE did not exert promotional activity on urinary bladder carcinogenesis. However, papillomatosis of the urinary bladder developed in small numbers of the rats given ETBE at 1000 mg/kg/day but not in rats given 500 mg/kg/day or lower doses. 相似文献
13.
Kazumasa HONDA Ayako SUDO Kentaro IKEDA 《The Journal of reproduction and development》2013,59(6):569-574
The present experiments were undertaken to examine whether oxytocin cells in the
supraoptic nucleus receive synaptic inputs from the contralateral supraoptic nucleus
or paraventricular nucleus. Using urethane-anesthetized lactating rats, extracellular
action potentials were recorded from single oxytocin or vasopressin cells in the
supraoptic nucleus. Electrical stimulation was applied to the contralateral
supraoptic nucleus or paraventricular nucleus, and responses of oxytocin or
vasopressin cells were analyzed by peri-stimulus time histogram or by change in
firing rate of oxytocin or vasopressin cells. Electrical stimulation of the
contralateral supraoptic nucleus or paraventricular nucleus did not cause antidromic
excitation in oxytocin or vasopressin cells but caused orthodromic responses.
Although analysis by peri-stimulus time histogram showed that electrical stimulation
of the contralateral supraoptic nucleus or paraventricular nucleus caused orthodromic
excitation in both oxytocin and vasopressin cells, the proportion of excited oxytocin
cells was greater than that of vasopressin cells. Train stimulation applied to the
contralateral supraoptic nucleus or paraventricular nucleus at 10 Hz increased firing
rates of oxytocin cells and decreased those of vasopressin cells. The results of the
present experiments suggest that oxytocin cells in the supraoptic nucleus receive
mainly excitatory synaptic inputs from the contralateral supraoptic nucleus and
paraventricular nucleus. Receipt these synaptic inputs to oxytocin cells may
contribute to the synchronized activation of oxytocin cells during the milk ejection
reflex. 相似文献
14.
Chie FUJINO Satoko WADA Tomohiko KONOIKE Koki TOYOTA Yuko SUGA Jun-ichi IKEDA 《Soil Science and Plant Nutrition》2008,54(4):534-542
The effect of organic amendment on the resistance and resilience of the organic matter decomposing activity was compared between soils amended with compost and with chemical fertilizers. The impact of metam sodium disinfection on cellulose-decomposing activity and on the number of nematodes in three types of soils was periodically measured. In an andosol, cellulose-decomposing activity was significantly suppressed by soil disinfection only in the chemically fertilized soil (CF-soil) and not in the soils to which cow manure compost and okara (the residue in tofu production)/coffee compost was added. In a brown lowland soil, cellulose-decomposing activity was significantly suppressed by soil disinfection in the CF-soil, but not in the soils to which higher amounts of cow manure compost and pig manure compost had been added. In a red-yellow soil, cellulose-decomposing activity was significantly suppressed by soil disinfection in all soils, but its resilience was higher in the soils to which cow manure compost or coffee compost was added compared with the CF-soil. Total numbers of nematodes were markedly decreased by soil disinfection in all soils. These results may suggest that the resistance and resilience of cellulose-decomposing activity against soil disinfection were enhanced by organic amendments, while disinfection had fatal effects on soil nematodes. In most of the organically amended soils, the mean weight diameters of aggregates were larger compared with the CF-soils, suggesting that highly structured soil pore networks may provide shelters for the soil microbes responsible for cellulose decomposition against disinfection. This hypothesis was supported by the result that the resistance of cellulose-decomposing activity against soil disinfection decreased when the soil structure was destroyed by grinding in a mortal and pestle. 相似文献
15.
Takishita Kiyotaka Kawai Rihoko Tsutsumi Ayaka Tanifuji Goro Otsubo Mayuko 《Fisheries Science》2020,86(4):633-643
Fisheries Science - Tidal flats are ecologically important as they support a large community of animals (e.g., crabs, mollusks, and polychaetes) and restore water quality. However, information... 相似文献
16.
We report that in a leaf insect, Phyllium westwoodii Wood-Mason (Phasmatodea: Phylliidae), two differing apertures can be used for oviposition, the color of eggs being affected by which aperture is used. Eggs which are forcibly propelled from the internal space within the valvulae of the abdomen are brown, whereas white eggs emerge slowly from the opening between the eighth sternite and the valvulae, and are deposited close to the ventral surface of the female. This unusual oviposition system does not appear to have been previously reported in phasmatids or in other insects. 相似文献
17.
Machiko Yamada Mayuko Otsubo Yuki Tsutsumi Chiaki Mizota Naoki Iida Kazuma Okamura Masashi Kodama Akira Umehara 《Fisheries Science》2013,79(6):923-934
The genus Skeletonema includes phytoplankton species that are important primary producers in marine food chains. Brackish waters have been reported to be one of the important habitats of some species of Skeletonema. To elucidate the species diversity of Skeletonema in brackish waters, we investigated three Japanese brackish bodies of water: the coastal waters of Toyama Bay, a tidal area of the Chikugo River, and a constructed reservoir in Isahaya Bay. We used molecular analysis based on large subunit rDNA and fine morphological structure to identify species. Skeletonema costatum s.s. (sensu stricto) was isolated at salinities as low as 0.6, but Skeletonema dohrnii, Skeletonema subsalsum, and Skeletonema tropicum were not found at salinities below 11.0. S. costatum s.s. could survive transfer from a medium with a salinity of 15 to a salinity of 2, but S. dohrnii did not survive in the same experiment. Only S. costatum s.s. germinated from the sediment of a reservoir in which the salinity was 0.1–1.4; incubation conditions included temperatures of 10, 15, 20, 25, and 30 °C and salinities of 5 and 30. Skeletonema costatum s.s. was identified as the species most adaptable to low-level salinity variations throughout its lifecycle. 相似文献
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19.
Cloned porcine embryos can maintain developmental ability after cryopreservation at the morula stage
Nakano K Matsunari H Nakayama N Ogawa B Kurome M Takahashi M Matsumoto M Murakami H Kaji Y Nagashima H 《The Journal of reproduction and development》2011,57(2):312-316
The aim of the present study was to clarify the overall efficiency of porcine somatic cell nuclear transfer (SCNT) by incorporating cryopreservation of the cloned embryos before transfer. The SCNT embryos reconstructed with preadipocytes and in vitro-matured (IVM) oocytes were cultured to harvest morula stage embryos; they were then subjected to delipation (removal of cytoplasmic lipid droplets) and vitrification. After warming and culture, the embryos developing to blastocysts were transferred to recipients to obtain cloned piglets. From 372 reconstructed embryos, 188 (50.5%) reached the morula stage and 117 (31.5%) developed to blastocysts after vitrification. Transfer of 98 (26.3%) morphologically normal blastocysts gave rise to 6 (1.6%) piglets, including 1 stillborn. The efficiency of the cloned piglet production was comparable with that obtained using SCNT embryos without cryopreservation (2.7%, 17/635). Here, we demonstrate that porcine somatic cell cloning can be performed without a significant reduction in efficiency even when the SCNT embryos are cryopreserved before transfer. 相似文献
20.
Koreishi M Zhang D Imanaka H Imamura K Adachi S Matsuno R Nakanishi K 《Journal of agricultural and food chemistry》2006,54(1):72-78
A novel enzyme that catalyzes efficient hydrolysis of capsaicin (8-methyl-N-vanillyl-6-nonenamide) was isolated from the culture broth of Streptomyces mobaraensis. The enzyme consisted of two dissimilar subunits with molecular masses of 61 and 19 kDa. The enzyme was activated and stabilized in the presence of Co2+. It showed a pH optimum of about 8 and was stable at temperatures of up to 55 degrees C for 1 h at pH 7.8. The specific activity of the enzyme for the hydrolysis of capsaicin was 10(2)-10(4) times higher than those for the enzymes reported to date. In an aqueous/n-hexane biphasic system, capsaicin analogues such as octanoyl, decanoyl, and lauroyl vanillylamides were synthesized from the corresponding fatty acids and vanillylamine at yields of 50% or greater. In addition, the enzyme catalyzed the deacylation of N-lauroyl-L-amino acids and N-lauroyl-L-dipeptides and the efficient synthesis of Nalpha-lauroyl-L-lysine, Nepsilon-lauroyl-L-lysine, and various N-lauroyl-peptides in aqueous solution in both the absence and the presence of glycerol. 相似文献