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281.
We investigated the effect of light intensity on diurnal differences in secondary wall formation of tracheids. Saplings of
Cryptomeria japonica were grown in growth chambers with light intensity cycles set for 12-h high light: 12-h low light by combining two of four
light intensity levels: 1.5, 2.8, 4.3, and 10.0 klx. Volumetric changes of differentiating cells were monitored by measuring
the tangential strain on the inner bark surface, and the innermost surface of developing secondary walls of differentiating
tracheids during the high-light and low-light periods was observed by field-emission scanning electron microscopy. Changes
in the aspects of the innermost surface of developing secondary walls and the tangential strain corresponded to changes in
the light intensity level. Cellulose microfibrils were clearly observed when the light intensity was high (10.0 or 4.3 klx)
and the volume of differentiating cells was low, while abundant amorphous material was observed when the light intensity was
lowest (1.5 klx) and the cells were turgid, regardless of the light intensity cycle. These results suggest that the diurnal
periodicity in the supply of cell wall components to developing secondary walls is associated with changes in light intensity
during the photoperiodic cycle. 相似文献
282.
Masato Kamisako Hiroyuki Sase Taeko Matsui Hiroko Suzuki Akiomi Takahashi Takuji Oida Makoto Nakata Tsumugu Totsuka Hiromasa Ueda 《Water, air, and soil pollution》2008,195(1-4):51-61
Fluxes of major ions in rainfall (RF), throughfall plus stemflow (TF + SF), and stream water (SW) were measured for five water years in a small catchment of a Japanese cedar forest near the Sea of Japan. The fluxes of most ions in RF and in TF + SF, including the non-sea-salt constituents, increased from late autumn to midwinter owing to the seasonal westerly wind. The concentrations of most ions in SW showed no obvious seasonal trend during the study period, whereas ${\text{NO}}_3 ^ - $ concentrations were lowest in summer, with a small seasonality. The Ca2+ and Mg2+ outputs in SW were approximately 3.7 and 1.8 times the TF + SF inputs of these cations, respectively. The large net outputs of base cations in the catchment may indicate a decrease in the soil's acid-neutralizing capacity. Annual dissolved inorganic nitrogen inputs in RF and in TF + SF were 17.7 and 17.9 kg N ha?1 year?1, respectively, which exceeded previously published thresholds in Europe and the U.S. (i.e., the values at which these inputs increased ${\text{NO}}_3 ^ - $ levels in SW) and equaled the highest level of nitrogen deposition previously reported in Japan. The ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW were relatively high even in summer. During high-precipitation events, ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW increased with increasing water discharge, and the pH decreased simultaneously during several events. Nitrogen deposition may contribute to the high ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW and the temporary acidification that occurred during the rain events. 相似文献
283.
Chemical chaperones reduce ER stress and restore glucose homeostasis in a mouse model of type 2 diabetes 总被引:1,自引:0,他引:1
Ozcan U Yilmaz E Ozcan L Furuhashi M Vaillancourt E Smith RO Görgün CZ Hotamisligil GS 《Science (New York, N.Y.)》2006,313(5790):1137-1140
Endoplasmic reticulum (ER) stress is a key link between obesity, insulin resistance, and type 2 diabetes. Here, we provide evidence that this mechanistic link can be exploited for therapeutic purposes with orally active chemical chaperones. 4-Phenyl butyric acid and taurine-conjugated ursodeoxycholic acid alleviated ER stress in cells and whole animals. Treatment of obese and diabetic mice with these compounds resulted in normalization of hyperglycemia, restoration of systemic insulin sensitivity, resolution of fatty liver disease, and enhancement of insulin action in liver, muscle, and adipose tissues. Our results demonstrate that chemical chaperones enhance the adaptive capacity of the ER and act as potent antidiabetic modalities with potential application in the treatment of type 2 diabetes. 相似文献
284.
Chimeric mice with humanized liver as a model for testing organophosphate and carbamate pesticide exposure
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Hiroshi Suemizu Kenji Kawai Norie Murayama Masato Nakamura Hiroshi Yamazaki 《Pest management science》2018,74(6):1424-1430