Seasonal and Annual Fluxes of Inorganic Constituents in a Small Catchment of a Japanese Cedar Forest near the Sea of Japan     

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   

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   

Chimeric mice with humanized liver as a model for testing organophosphate and carbamate pesticide exposure          下载免费PDF全文

Hiroshi Suemizu  Kenji Kawai  Norie Murayama  Masato Nakamura  Hiroshi Yamazaki 《Pest management science》2018,74(6):1424-1430

BACKGROUND

Diagnosis of acute intoxication with organophosphate (OP) or carbamate (CM) pesticides in humans is achieved by measuring plasma butyrylcholinesterase (BuChE) activity. However, BuChE activity is not an ideal biomarker in experimental animal models. The aim of this study was to establish an experimental mouse model for evaluating exposure to OP and CM pesticides by monitoring BuChE activity using chimeric mice in which the liver was reconstituted with human hepatocytes.

RESULTS

A single oral administration of acephate (300 mg/kg), chlorpyrifos (10 mg/kg), fenobucarb (300 mg/kg) or molinate (250 mg/kg) in chimeric mice led to inhibition of >95%, > 95%, 28% and 60% of plasma BuChE activity after 7, 0.5, 0.5 and 7 h, respectively. Dose‐dependent decreases in plasma BuChE activity were also observed for acephate and chlorpyrifos. A 5‐day repeated‐dose study with 10 or 30 mg/kg acephate found a constitutive reduction in plasma BuChE activity to 80% and 70% of pre‐dose levels, respectively.

CONCLUSION

Changes in plasma BuChE activity in chimeric mice with humanized liver clearly reflected the exposure levels of OP and CM pesticides. These results suggest that the humanized‐liver mouse model may be suitable for estimating levels of exposure to these pesticides in humans. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Cell-mediated and humoral immune response to non-viable Mycoplasma pulmonis in mice enhanced by cross-linked ricin     

M Kishima  C Kuniyasu  M Eguchi  M Yamamoto  E Imamura 《Veterinary microbiology》1987,14(2):145-156

The enhancing effect of cross-linked ricin (CL-ricin) on the cell-mediated and humoral immune response of mice to non-viable Mycoplasma pulmonis was studied. The cell-mediated immune response was evaluated by means of the delayed-type footpad swelling, and the humoral immune response by means of the indirect hemagglutination test. Mice pre-treated subcutaneously with non-viable M. pulmonis and CL-ricin showed significantly increased delayed-type footpad swelling when they were injected in the footpad with the same antigen 7 days later. Delayed-type footpad swelling was not detected in mice pre-treated only with non-viable M. pulmonis or CL-ricin followed by footpad injection with non-viable M. pulmonis. Injection of non-viable M. pulmonis in the footpad on Days 3, 7, 14, 21, 28, 35 and 42 after pre-treatment with non-viable M. pulmonis and CL-ricin resulted in significant footpad swelling. Delayed-type footpad swelling was transferred by intravenous injection of spleen cells from mice which had been pre-treated 7 days previously with non-viable M. pulmonis and CL-ricin into non-treated recipient mice. Intravenous injection of anti-mouse thymus cell serum into mice previously pre-treated with non-viable M. pulmonis and CL-ricin reduced the delayed-type footpad swelling significantly. Mice pre-treated subcutaneously with non-viable M. pulmonis and CL-ricin showed a marked increase in serum antibody titers compared with those that received non-viable M. pulmonis alone.  相似文献