Estimation of relative contribution of “mobile phycobilisome” and “energy spillover” in the light–dark induced state transition in Spirulina platensis
- 176 Downloads
Previously, it was clarified that phycobilisome (PBS) mobility and energy spillover were both involved in light-to-dark induced state transitions of intact Spirulina platensis cells. In this work, by taking advantage of the characteristic fluorescence spectra of photosystem I (PSI) trimers and monomers as indicators, the relative contributions for the “mobile PBS” and “energy spillover” are quantitatively estimated by separating the fluorescence contribution of PBS mobility from that of PSI oligomeric change. Above the phase transition temperature (T PT) of the membrane lipids, the relative proportion of the contributions is invariable with 65% of “mobile PBS” and 35% of “energy spillover”. Below T PT, the proportion for the “mobile PBS” becomes larger under lowering temperature even reaching 95% with 5% “energy spillover” at 0°C. It is known that lower temperature leads to a further light state due to a more reduced or oxidized PQ pool. Based on the current result, it can be deduced that disequilibrium of the redox state of the PQ pool will trigger PBS movement instead of change in the PSI oligomeric state.
KeywordsCyanobacterium State transition Phycobilisomes Mobility Energy spillover Relative contribution
The research is supported by the National Natural Science Foundation of China (NSFC) (No. 30570422, 502211201, 90306013 and 3047037).
- Govindjee, Satoh K (1986) Fluorescence properties of chlorophyll b- and chlorophyll c-containing algae. In: Govindjee, Amesz J, Fork DC (eds) Light emission by plants and bacteria. Academic Press, Orlando, pp 497–537Google Scholar
- Mullineaux CW (1992) Excitation energy transfer from phybobilisomes to photosytem I in a cyanobacterium. Biochim Biophys Acta 1100:285–292Google Scholar
- Papageorgiou GC, Govindjee (2005) Chlorophyll a fluorescence: a bit of basics and history. In: Papageorgiou GC, Govindjee (eds) Chlorophyll a fluorescence: a signature of photosynthesis. Advances in photosynthesis and respiration, vol 19. Springer, The Netherlands, pp 1–42Google Scholar
- Porra RJ, Thompson WA, Kriedemann PE (1989) Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophylls a and b extracted with four different solvent; verification of the concentration of chlorophyll standards by absorption spectroscopy. Biochim Biophys Acta 975:384–394CrossRefGoogle Scholar
- Rabinowitch E, Govindjee (1969) Photosynthesis. John Wiley and Sons Inc., NY, pp 34–36Google Scholar
- Zarrouk C (1966) Contribution to the study of a cyanophycea: influence of various physical and chemical factors on the growth and photosynthesis of Spirulina maxima. Ph.D. Thesis, University of Paris, ParisGoogle Scholar