| 摘要: |
| 采用分离、原位扫描和光谱分析方法,将管藻目绿藻刺松藻和假根羽藻的叶绿体、类囊体膜、PSI复合物及其亚复合物的结构及光谱性质与软丝藻和菠菜做了比较。结果表明,管藻目绿藻缺少作为高等植物PSI表征的730nm长波荧光,这一特异现象主要与LHCI结构的差异有关。采用PAGE法分离出的4种PSI复合物的荧光主发射峰分别在698、690、685和677nm,在710—715nm处有一个随分子量减小而逐渐明显的肩峰。不同去污剂处理只影响PSI复合物荧光峰的高低,而不影响其峰位。PAGE再分离得到的假根羽藻LHCI由24–27.5kDa的4种多肽构成,Chl-a/Chl-b=1.2, 77K荧光发射峰在682nm;CCI只含有67和56kDa多肽,是叶绿体715nm荧光的发射部位。当有LHCI存在时,该荧光不明显。 |
| 关键词: 管藻目 PSI CCI LHCI 长波荧光 绿藻 菠菜 |
| DOI： |
| 分类号: |
| 基金项目:国家“九五”攻关资助项目96-C01-05-01号 |
附件 |
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| CHARACTERIZATION OF PSI FLUORESCENCE IN SIPHONOUS MARINE GREEN ALGAE, CODIUM FRAGILE AND BRYOPSIS CORTICULANS |
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CHEN Min, LI Ai-Fen, ZHOU Bai-Cheng
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Institute of Oceanology, The Chinese Academy of Sciences, Qingdao, 266071
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| Abstract: |
| Structural and spectral characters of chloroplast, thylakoids, PSI chlorophyll-protein complexes and their sub-complexes LHCI and CCI isolated from two species of siphonous green algae, Codium fragile and Bryopsis corticulans, were studied and compared with those of green alga Ulothrix flacca and spinach. Affection on the long wavelength of PSI complexes of different types of detergents was also investigated. The results showed that all of the three green algae lacked the 730nm characteristic emission band which is regarded as a symbol of PSI in higher plants. The main fluorescence emissions in chloroplasts and thylakoids isolated from C. fragile and B. corticulans were all near 685nm and 695nm, a shoulder around 710–715nm with an unknown origin was also identified. The largest PSI complex resolved from spinach thylakoids by PAGE has a long wavelength emission around 730nm, U. flacca at 715nm. The emission bands of three CPIa complexes from C. fragile and B. corticulans were associated with single wide peaks, with wavelengths of shorter than 700nm, at 698, 690, 685nm, respectively. CPI of spinach had an emission maximum at 720nm and U. flacca at 715nm, C . fragile and B. corticulans at 677nm; the peak between 710–715nm was half-hidden. The fluorescent peaks of PSI complexes resolved by three different detergents, SDS, DMG and DOC, differed in their heights other than their wavelengths. It suggests that the separating procedure and the detergents have no relationship with the differences of PSI fluorescence emission positions among spinach, U. flacca and two species of siphonous green algae. By further fraction of PSI complexes under PAGE, the light-harvesting complex LHCI and core complex CCI of B. corticulans were obtained. LHCI consisted of four peptides of 27.5, 26.2, 26 and 24kDa, and had a fluorescence emission around 682–683nm other than 730nm in higher plants at 77K. It attached more tightly with CCI than those of U. flacca or spinach. CCI depleting of LHCI contained only 67 and 56 kDa peptides, and meanwhile, its fluorescent band around 710–715nm became remarkable. The un-located fluorescence emission in two species siphonous chloroplasts was originated from CCI. The presence of LHCI made the CCI fluorescence band half-hidden. Further, the differences of LHCI peptides and fluorescence characteristics were the main structural reason that caused the difference of fluorescence in siphonous green algae. |
| Key words: Siphonales, PSI , CCI, LHCI, Long-wavelength fluorescence, Green algae, Spinach |
