Time and Space Thinking that is composed of time and space thinking is brought up in civil engineering. This paper makes a detailed analysis on application and role of time and space thinking in knowledge system and l...Time and Space Thinking that is composed of time and space thinking is brought up in civil engineering. This paper makes a detailed analysis on application and role of time and space thinking in knowledge system and learning method of civil engineering and put forward time and space thinking to be similar with philosophical view of time and space. Time and space thinking is a scientific method, therefore, it is suggested to make students active in having such idea and strengthen students＇ understanding on time and space thinking, which will helping students recognize knowledge system and stimulate innovative abilities.展开更多
All organisms with oxygenic photosynthesis contain two photosystems: photosystemⅠ(PSⅠ) and photo-system Ⅱ (PSⅡ). The minimal photosystem Ⅱ particles which are photochemically active contain three subunits: D1, D2...All organisms with oxygenic photosynthesis contain two photosystems: photosystemⅠ(PSⅠ) and photo-system Ⅱ (PSⅡ). The minimal photosystem Ⅱ particles which are photochemically active contain three subunits: D1, D2 and cytochrome b559 (Cyt b559). The function of Cyt b559 remains unclear. We have successfully overexpressed the psbF gene, encoding the b subunit of Cyt b559, from a marine cyanobacterium Synechococcus sp. PCC 7002 as a fusion gene and obtained a redox-active form of Cyt b559. When the N-terminal GST protein of the fusion gene product was removed with thrombin, the PsbF protein was still re-dox-active, suggesting that the recombinant PsbF can form dimer in Escherichia coli. The absorption spectra of either the oxidized form or the reduced form of both GST fusion protein and the purified PsbF dimer and the difference spec-tra between the two forms are the same as that of the Cyt b559 isolated from the higher plants. Redox titration analysis of recombinant PsbF showed that the mid-point redox potential of the recombinant Cyt b559 was approximately 50 mV, which is close to the low potential of Cyt b559. The results are helpful to the understanding of localization and function of Cyt b559 on thylakoid membranes.展开更多
文摘Time and Space Thinking that is composed of time and space thinking is brought up in civil engineering. This paper makes a detailed analysis on application and role of time and space thinking in knowledge system and learning method of civil engineering and put forward time and space thinking to be similar with philosophical view of time and space. Time and space thinking is a scientific method, therefore, it is suggested to make students active in having such idea and strengthen students＇ understanding on time and space thinking, which will helping students recognize knowledge system and stimulate innovative abilities.
基金supported by the State"973"Key Basic Research Project(Grant No.G1998010100)the National Natural Science Foundation of China(Grant No.39535002).
文摘All organisms with oxygenic photosynthesis contain two photosystems: photosystemⅠ(PSⅠ) and photo-system Ⅱ (PSⅡ). The minimal photosystem Ⅱ particles which are photochemically active contain three subunits: D1, D2 and cytochrome b559 (Cyt b559). The function of Cyt b559 remains unclear. We have successfully overexpressed the psbF gene, encoding the b subunit of Cyt b559, from a marine cyanobacterium Synechococcus sp. PCC 7002 as a fusion gene and obtained a redox-active form of Cyt b559. When the N-terminal GST protein of the fusion gene product was removed with thrombin, the PsbF protein was still re-dox-active, suggesting that the recombinant PsbF can form dimer in Escherichia coli. The absorption spectra of either the oxidized form or the reduced form of both GST fusion protein and the purified PsbF dimer and the difference spec-tra between the two forms are the same as that of the Cyt b559 isolated from the higher plants. Redox titration analysis of recombinant PsbF showed that the mid-point redox potential of the recombinant Cyt b559 was approximately 50 mV, which is close to the low potential of Cyt b559. The results are helpful to the understanding of localization and function of Cyt b559 on thylakoid membranes.
