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 mycosporine-like amino acid/s
Gast, Rebecca J.
Papageorgiou, George C.
MetadataShow full item record
KeywordKleptoplast; Phaeocystis antarctica; Photosystems I, II; Photosynthetic oxygen evolution; Ross Sea dinoflagellate
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 683 nm (F683) at 277 K and at 689 (F689) at 77 K. Second derivative analysis of the F689 band at 77 K revealed two individual contributions centered at 683 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 (436 nm) but also by mycosporine-like aminoacids (MAAs)-selective light (345 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 77K, of p-NTP resolved fluorescence spectra, as well as of PSII-driven oxygen evolution activities, PS II appears substantially less active (~ 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.
© The Author(s), 2016. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Biochimica et Biophysica Acta (BBA) - Bioenergetics 1858 (2017): 189-195, doi:10.1016/j.bbabio.2016.12.002.
Suggested CitationPreprint: Stamatakis, Kostas, Vayenos, Dimitris, Kotakis, Christos, Gast, Rebecca J., Papageorgiou, George C., "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 mycosporine-like amino acid/s", 2016-12, https://doi.org/10.1016/j.bbabio.2016.12.002, https://hdl.handle.net/1912/8615
Showing items related by title, author, creator and subject.
Phaeocystis antarctica blooms strongly influence bacterial community structures in the Amundsen Sea polynya Delmont, Tom O.; Hammar, Katherine M.; Ducklow, Hugh W.; Yager, Patricia L.; Post, Anton F. (Frontiers Media, 2014-12-19)Rising temperatures and changing winds drive the expansion of the highly productive polynyas (open water areas surrounded by sea ice) abutting the Antarctic continent. Phytoplankton blooms in polynyas are often dominated ...
Mesoscale variability in intact and ghost colonies of Phaeocystis antarctica in the Ross Sea : distribution and abundance Smith, Walker O.; McGillicuddy, Dennis J.; Olson, Elise M. B.; Kosnyrev, Valery; Peacock, Emily E.; Sosik, Heidi M. (2016-05)Phaeocystis, a genus with a cosmopolitan distribution and a polymorphic life cycle, was observed during summer in the Ross Sea, Antarctica, where large blooms of this haptophyte regularly occur. The mesoscale vertical and ...
Constraints on the vital effect in coccolithophore and dinoflagellate calcite by oxygen isotopic modification of seawater Hermoso, Michael; Horner, Tristan J.; Minoletti, Fabrice; Rickaby, Rosalind E. M. (2014-05)In this study, we show that there are independent controls of 18O/16O and 13C/12C fractionation in coccolithophore and dinoflagellate calcite due to the contrasting kinetics of each isotope system. We demonstrate that ...