应用 DNA 解旋荧光测定(FADU)法,研究γ射线(0.1～4.0Gy)和低剂量γ射线(0.5～8.0cGY)照射对淋巴细胞 DNA 断裂的影响,以及低剂量γ射线照射后 DNA 修复功能的变化。结果表明,FADU 法测得的0.3～4Gyγ射线所致的淋巴细胞 DNA 断裂与剂...应用 DNA 解旋荧光测定(FADU)法,研究γ射线(0.1～4.0Gy)和低剂量γ射线(0.5～8.0cGY)照射对淋巴细胞 DNA 断裂的影响,以及低剂量γ射线照射后 DNA 修复功能的变化。结果表明,FADU 法测得的0.3～4Gyγ射线所致的淋巴细胞 DNA 断裂与剂量呈线性关系(y=0.06+13.4X);0.5～8.0cGyγ射线对静止期淋巴细胞和照后丝裂原激活的淋巴细胞的双链 DNA 百分数无影响。说明低剂量照射不能减少细胞内固有(本底水平)的 DNA 断裂;低剂量辐射(2.0cGy)对15Gyγ线照射所引起的 DNA 断裂的修复(37℃,15～60min)有促进作用,但对最终修复程度(37℃,120min)无明显提高。展开更多
Arthrospira platensis is an economically important cyanobacterium; and it has been used widely in food and pharmaceutical industries. The phycocyanin(PC) from A. platensis is extremely valuable in medicine and molecul...Arthrospira platensis is an economically important cyanobacterium; and it has been used widely in food and pharmaceutical industries. The phycocyanin(PC) from A. platensis is extremely valuable in medicine and molecular biology due to its antioxidation and anti-tumoring activity and applicability as fluorescence protein tag. In present study, two recombinant plasmids, one contained the phycocyanobilin(PCB)-producing genes(hox1 and pcyA) while the other contained the phycobiliprotein gene(cpcB) and the lyase gene(either cpcS/U or cpcT), were constructed and synchronically transferred into E. coli in order to test the the activities of relevant lyases for catalysing PCB addition to CpcB during synthesizing fluorescent PC holo-β-subunit(β-PC) of A. platensis. As was evidenced by the fluorescence emitted at a peak specific for PC, CpcB was successfully synthesized in E. coli, to which co-expressed PCBs attached though at a relatively low efficiency. The results showed that the attachment of PCBs to CpcB were carried out mainly by co-expressed CpcS/U but CpcB also showed some autocatalytic activity. Currently, no CpcT activity was detected in this E. coli expression system. Further studies will be conducted to improve the efficiency of fluorescent PC synthesis in E. coli.展开更多
文摘应用 DNA 解旋荧光测定(FADU)法,研究γ射线(0.1～4.0Gy)和低剂量γ射线(0.5～8.0cGY)照射对淋巴细胞 DNA 断裂的影响,以及低剂量γ射线照射后 DNA 修复功能的变化。结果表明,FADU 法测得的0.3～4Gyγ射线所致的淋巴细胞 DNA 断裂与剂量呈线性关系(y=0.06+13.4X);0.5～8.0cGyγ射线对静止期淋巴细胞和照后丝裂原激活的淋巴细胞的双链 DNA 百分数无影响。说明低剂量照射不能减少细胞内固有(本底水平)的 DNA 断裂;低剂量辐射(2.0cGy)对15Gyγ线照射所引起的 DNA 断裂的修复(37℃,15～60min)有促进作用,但对最终修复程度(37℃,120min)无明显提高。
基金supported by the National Science and Technology Major Project of China (2008ZX08001-004)
文摘Arthrospira platensis is an economically important cyanobacterium; and it has been used widely in food and pharmaceutical industries. The phycocyanin(PC) from A. platensis is extremely valuable in medicine and molecular biology due to its antioxidation and anti-tumoring activity and applicability as fluorescence protein tag. In present study, two recombinant plasmids, one contained the phycocyanobilin(PCB)-producing genes(hox1 and pcyA) while the other contained the phycobiliprotein gene(cpcB) and the lyase gene(either cpcS/U or cpcT), were constructed and synchronically transferred into E. coli in order to test the the activities of relevant lyases for catalysing PCB addition to CpcB during synthesizing fluorescent PC holo-β-subunit(β-PC) of A. platensis. As was evidenced by the fluorescence emitted at a peak specific for PC, CpcB was successfully synthesized in E. coli, to which co-expressed PCBs attached though at a relatively low efficiency. The results showed that the attachment of PCBs to CpcB were carried out mainly by co-expressed CpcS/U but CpcB also showed some autocatalytic activity. Currently, no CpcT activity was detected in this E. coli expression system. Further studies will be conducted to improve the efficiency of fluorescent PC synthesis in E. coli.
