Previous studies have shown that Arabidopsis equilibrative nucleoside transporters （AtENTs） possess transport activities when produced in yeast cells and are differentially expressed in Arabidopsis organs. Herein, w...Previous studies have shown that Arabidopsis equilibrative nucleoside transporters （AtENTs） possess transport activities when produced in yeast cells and are differentially expressed in Arabidopsis organs. Herein, we report further analysis on the nucleoside transport activities and transcriptional patterns of AtENT members. The recombinant proteins of AtENTs 3, 6, and 7, but not those of AtENTs 1, 2, 4, and 8, were found to transport thymidine with high affinity. Contrary to previ- ous suggestion that AtENT 1 may not transport uridine, this work showed that recombinant AtENT 1 was a pH-dependent and high-affinity transporter of uridine. When grown on MS plates, the AtENT3 knockout plants were more tolerant to the cytotoxic uridine analog 5-fluorouridine than wild-type plants and the knockout plants ofAtENT 1 or AtENT6. Con- sistent with this observation, the AtENT3 knockout line exhibited a significantly decreased ability to take up [^3H]uridine via the roots when compared with wild-type plants and the plants with mutated AtENT 1 or AtENT6. This indicates that AtENT3, but not AtENTs 1 and 6, is the main transporter for uridine uptake in Arabidopsis roots. The transcription of AtENTs 1, 3, 4, 6, 7, and 8 was regulated in a complex manner during leaf development and senescence. In contrast, the six AtENT members were coordinately induced during seed germination. This work provides new information on the transport properties of recombinant AtENT proteins and new clues for future studies of the in vivo transport activities and physiological functions of the different ENT proteins in Arabidopsis plants.展开更多
FeY zeolites were prepared by three different secondary synthetic methods. Samples were characterized with XRD, IR, ESR, MBS and XPS techniques. The results showed that more iron ions were inserted into the framework ...FeY zeolites were prepared by three different secondary synthetic methods. Samples were characterized with XRD, IR, ESR, MBS and XPS techniques. The results showed that more iron ions were inserted into the framework of zeolite when the sample was pretreated with (NH4)(2)SiF6 aqueous solution. The structure of such zeolites has obviously changed due to the iron ions inserted into the framework.展开更多
ZnO particles about 200 nm were prepared through a facile hydrothermal method.Compared with single ozonation,the degradation efficiency of phenol increased about 23.7%and the degradation efficiency of intermediates im...ZnO particles about 200 nm were prepared through a facile hydrothermal method.Compared with single ozonation,the degradation efficiency of phenol increased about 23.7%and the degradation efficiency of intermediates improved about four times in the presence of ZnO at 298 K.In addition,the catalyst had good stability in the ozonation process.The influence of temperature was investigated and it was found that the better catalysis efficiency could be obtained at lower temperature.展开更多
基金This work was supported by grants from the National Natural Science Foundation of China （39770491） the Chinese Academy of Sciences （KSCX2-SW-304）.
文摘Previous studies have shown that Arabidopsis equilibrative nucleoside transporters （AtENTs） possess transport activities when produced in yeast cells and are differentially expressed in Arabidopsis organs. Herein, we report further analysis on the nucleoside transport activities and transcriptional patterns of AtENT members. The recombinant proteins of AtENTs 3, 6, and 7, but not those of AtENTs 1, 2, 4, and 8, were found to transport thymidine with high affinity. Contrary to previ- ous suggestion that AtENT 1 may not transport uridine, this work showed that recombinant AtENT 1 was a pH-dependent and high-affinity transporter of uridine. When grown on MS plates, the AtENT3 knockout plants were more tolerant to the cytotoxic uridine analog 5-fluorouridine than wild-type plants and the knockout plants ofAtENT 1 or AtENT6. Con- sistent with this observation, the AtENT3 knockout line exhibited a significantly decreased ability to take up [^3H]uridine via the roots when compared with wild-type plants and the plants with mutated AtENT 1 or AtENT6. This indicates that AtENT3, but not AtENTs 1 and 6, is the main transporter for uridine uptake in Arabidopsis roots. The transcription of AtENTs 1, 3, 4, 6, 7, and 8 was regulated in a complex manner during leaf development and senescence. In contrast, the six AtENT members were coordinately induced during seed germination. This work provides new information on the transport properties of recombinant AtENT proteins and new clues for future studies of the in vivo transport activities and physiological functions of the different ENT proteins in Arabidopsis plants.
文摘FeY zeolites were prepared by three different secondary synthetic methods. Samples were characterized with XRD, IR, ESR, MBS and XPS techniques. The results showed that more iron ions were inserted into the framework of zeolite when the sample was pretreated with (NH4)(2)SiF6 aqueous solution. The structure of such zeolites has obviously changed due to the iron ions inserted into the framework.
基金the support from the National Natural Science Foundation of China(Nos. 20903048,20771046 and 21005031)the Fundamental Research Funds for the Central Universities(No. JUSRP30903)+1 种基金the Startup Foundation for Introduced Talents(Nos.20081789 and 20091207)the Science Foundation for Youth(Nos.2008LQN002 and 2009LQN11)
文摘ZnO particles about 200 nm were prepared through a facile hydrothermal method.Compared with single ozonation,the degradation efficiency of phenol increased about 23.7%and the degradation efficiency of intermediates improved about four times in the presence of ZnO at 298 K.In addition,the catalyst had good stability in the ozonation process.The influence of temperature was investigated and it was found that the better catalysis efficiency could be obtained at lower temperature.
