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- Gylle, A. Maria, 1965-, et al.
(author)
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Photosynthesis and relative amounts of photosynthetic proteins (D1, PsaA and Rubisco) in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae) : Photosynthesis and proteins in Fucus
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Other publication (other academic/artistic)abstract
- This study investigated if the photosynthetic maximum capacity (Pmax) is related to the relative amounts of D1 (PsbA), PsaA proteins and ribulose-1.5-bisphosphate carboxylase/ oxygenase (Rubisco) in the marine, Norwegian Sea (34-35 practical salinity units, psu) and the brackish, Bothnian Sea (4-5 psu) ecotypes of Fucus vesiculosus and in Fucus radicans. The results revealed higher Pmax in the marine ecotype of F. vesiculosus compared to the brackish Fucus species. The relative amounts of PsaA proteins or D1/PsaA (photosystem II/photosystem I; PSII/PSI) ratio did not indicate any differences between the Fucus strains whereas the relative amount of D1 was higher in the marine F. vesiculosus compared to F. radicans. The PSII/PSI ratios confirm an overweight of PSI in all three Fucus strains. The analyses of the relative amount of Rubisco indicated a greater amount in both ecotypes of F. vesiculosus compared to F. radicans, whereas no differences could be detected between the two ecotypes of F. vesiculosus. Therefore, we suggest that the amount of Rubisco contributed to the differences of Pmax between the marine ecotype of F. vesiculosus and F. radicans. The lower Pmax in the brackish ecotype of F. vesiculosus compared to the marine ecotype however must have another origin and we suggest further investigations of the CO2 fixation rate of Rubisco. The study also included an investigation of the effects of salinity on Pmax and the relative amount of D1, PsaA and Rubisco in the brackish ecotype of F. vesiculosus. Treatment of the algae for one week in 5, 10, 20 and 35 psu resulted in a higher Pmax at higher salinities and a maximum at 10 psu. These results were not reflected in the amount of D1 or Rubisco whereas analyses of the amount of PsaA revealed the highest amount of PsaA in algae treated in 10 psu. We suggest a need of more ATP by cyclic ATP formation to supply a greater Rubisco activity as an explanation.
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| 2. |
- Gylle, A. Maria, et al.
(author)
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Photosynthesis in relation to D1, PsaA and Rubisco in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae)
- 2013
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In: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 700:1, s. 109-119
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Journal article (peer-reviewed)abstract
- The aim of this study was to investigate photosynthetic differences between the marine, Norwegian Sea ecotype and the brackish, Bothnian Sea ecotype of F. vesiculosus and F. radicans and to see whether photosynthetic differences could be connected with the relative amounts of D1 protein (PSII), PsaA (PSI) protein and/or Rubisco. For this purpose, we tested if a higher photosynthetic maximum (P (max)) in the Atlantic Ocean ecotype of F. vesiculosus relative to the Baltic Sea ecotype, and an increase of the P (max) in Baltic Sea ecotype of F. vesiculosus at higher salinity, could be due to an increase in the relative amounts of Rubisco. The proteins have been evaluated on a relative basis. Immunoblot signals showed that the amount of Rubisco was higher in both ecotypes of F. vesiculosus than in F. radicans, but no differences could be detected between the two ecotypes of F. vesiculosus. The results suggest an uneven photosystem protein stoichiometry in Fucus, with more of the PSI protein PsaA relative to the PSII protein D1. The difference in P (max) between the two ecotypes of F. vesiculosus might be related to the difficulties for the algae to adapt to the environment in Bothnian Sea.
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