کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5507186 | 1400316 | 2017 | 23 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The extraordinary longevity of kleptoplasts derived from the Ross Sea haptophyte Phaeocystis antarctica within dinoflagellate host cells relates to the diminished role of the oxygen-evolving Photosystem II and to supplementary light harvesting by mycospor
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش گیاه شناسی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
The haptophyte Phaeocystis antarctica and the novel Ross Sea dinoflagellate that hosts kleptoplasts derived from P. antarctica (RSD; R.J. Gast et al., 2006, J. Phycol. 42 233-242) were compared for photosynthetic light harvesting and for oxygen evolution activity. Both chloroplasts and kleptoplasts emit chlorophyll a (Chl a) fluorescence peaking at 683Â nm (F683) at 277Â K and at 689 (F689) at 77Â K. Second derivative analysis of the F689 band at 77Â K revealed two individual contributions centered at 683Â nm (Fi-683) and at 689 (Fi-689). Using the p-nitrothiophenol (p-NTP) treatment of Kobayashi et al. (Biochim. Biophys. Acta 423 (1976) 80-90) to differentiate between Photosystem (PS) II and I fluorescence emissions, we could identify PS II as the origin of Fi-683 and PS I as the origin of Fi-689. Both emissions could be excited not only by Chl a-selective light (436Â nm) but also by mycosporine-like amino acids (MAAs)-selective light (345Â nm). This suggests that a fraction of MAAs must be proximal to Chls a and, therefore, located within the plastids. On the basis of second derivative fluorescence spectra at 77Â K, of p-NTP resolved fluorescence spectra, as well as of PSII-driven oxygen evolution activities, PS II appears substantially less active (~Â 1/5) in dinoflagellate kleptoplasts than in P. antarctica chloroplasts. We suggest that a diminished role of PS II, a known source of reactive oxygen species, and a diminished dependence on nucleus-encoded light-harvesting proteins, due to supplementary light-harvesting by MAAs, may account for the extraordinary longevity of RSD kleptoplasts.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1858, Issue 2, February 2017, Pages 189-195
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1858, Issue 2, February 2017, Pages 189-195
نویسندگان
Kostas Stamatakis, Dimitris Vayenos, Christos Kotakis, Rebecca J. Gast, George C. Papageorgiou,