Monitoring photosynthesis in individual cells of synechocystis sp. PCC 6803 on a picosecond timescale

S. B. Krumova, S. P. Laptenok, J. W. Borst, B. Ughy, Z. Gombos, G. Ajlani, H. Van Amerongen

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24 Citations (Scopus)

Abstract

Picosecond fluorescence kinetics of wild-type (WT) and mutant cells of Synechocystis sp. PCC 6803, were studied at the ensemble level with a streak-camera and at the cell level using fluorescence-lifetime-imaging microscopy (FLIM). The FLIM measurements are in good agreement with the ensemble measurements, but they (can) unveil variations between and within cells. The BE mutant cells, devoid of photosystem II (PSII) and of the light-harvesting phycobilisomes, allowed the study of photosystem I (PSI) in vivo for the first time, and the observed 6-ps equilibration process and 25-ps trapping process are the same as found previously for isolated PSI. No major differences are detected between different cells. The PAL mutant cells, devoid of phycobilisomes, show four lifetimes: ∼20 ps (PSI and PSII), ∼80 ps, ∼440 ps, and 2.8 ns (all due to PSII), but not all cells are identical and variations in the kinetics are traced back to differences in the PSI/PSII ratio. Finally, FLIM measurements on WT cells reveal that in some cells or parts of cells, phycobilisomes are disconnected from PSI/PSII. It is argued that the FLIM setup used can become instrumental in unraveling photosynthetic regulation mechanisms in the future.

Original languageEnglish
Pages (from-to)2006-2015
Number of pages10
JournalBiophysical journal
Volume99
Issue number6
DOIs
Publication statusPublished - 2010

ASJC Scopus subject areas

  • Biophysics

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    Krumova, S. B., Laptenok, S. P., Borst, J. W., Ughy, B., Gombos, Z., Ajlani, G., & Van Amerongen, H. (2010). Monitoring photosynthesis in individual cells of synechocystis sp. PCC 6803 on a picosecond timescale. Biophysical journal, 99(6), 2006-2015. https://doi.org/10.1016/j.bpj.2010.07.015