Abstract
In what appears to be a common theme for all phototrophs, heliobacteria exhibit complex modulations of fluorescence yield when illuminated with actinic light and probed on a time scale of μs to minutes. The fluorescence yield from cells of Heliobacterium modesticaldum remained nearly constant for the first 10-100 ms of illumination and then rose to a maximum level with one or two inflections over the course of many seconds. Fluorescence then declined to a steady-state value within about one minute. In this analysis, the origins of the fluorescence induction in whole cells of heliobacteria are investigated by treating cells with a combination of electron accepters, donors, and inhibitors of the photosynthetic electron transport, as well as varying the temperature. We conclude that fluorescence modulation in H. modesticaldum results from acceptor-side limitation in the reaction center (RC), possibly due to charge recombination between P800+ and A0-.
Original language | English (US) |
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Pages (from-to) | 283-292 |
Number of pages | 10 |
Journal | Photosynthesis research |
Volume | 104 |
Issue number | 2 |
DOIs | |
State | Published - Jun 1 2010 |
Keywords
- Fluorescence induction
- Fluorescence modulation
- Heliobacterium modesticaldum
ASJC Scopus subject areas
- Biochemistry
- Plant Science
- Cell Biology