Quinone-Dependent Delayed Fluorescence from the Reaction Center of Photosynthetic Bacteria

Turzó, Kinga; Laczko, Gabor; Filus, Z.; Maróti, Péter

doi:10.1016/s0006-3495(00)76270-9

Cited by 31 publications

(30 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The developed dipole across the RC is very stable and has a relaxation time of on the order of one second [10]. The separated charges can be removed from the RC by mediators, which in our experiments reported here, were ferrocene (Cp 2 Fe) and methyl viologen (MV 2+ ) [11,12]. In these reactions Cp 2 Fe donates an electron to the P side of the RC and converts to Cp 2 Fe + , whereas MV 2+ is reduced to MV + when an electron is removed from Q B side [13].…”

Section: Resultsmentioning

confidence: 81%

A Photovoltaic Device Using an Electrolyte Containing Photosynthetic Reaction Centers

et al. 2010

View full text Add to dashboard Cite

Abstract:The performance of bio-photovoltaic devices with a monolayer of the immobilized photosynthetic reaction center (RC) is generally low because of weak light absorption and poor charge transfer between the RC and the electrode. In this paper, a new bio-photovoltaic device is described in which the RC is dissolved in the electrolyte of an electrochemical cell. The charges generated by the illuminated RC are transferred to electrodes via mediators. The difference between the reaction rates of two types of mediator at the electrode surfaces determines the direction of the photocurrent in the device. Experimental results show that the magnitude of the photocurrent is proportional to the incident light intensity, and the current increases nonlinearly with an increase in the RC concentration in the electrolyte. With further optimization this approach should lead to devices with improved light absorption.

show abstract

Section: Resultsmentioning

confidence: 81%

A Photovoltaic Device Using an Electrolyte Containing Photosynthetic Reaction Centers

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Because of the significantly less complexity of the structure and function of the bacteria, the dark-light transition of the BChl fluorescence is considerably simpler than that of Chl fluorescence in higher plants. This property can be utilized if the bacteria are taken as model of the more advanced oxygenic systems, as was earlier successfully applied for herbicide binding (Stein et al 1984), flash-induced proton uptake (Maróti and Wraight 1988;Turzó et al 2000) or structure of the RC (Michel et al 1986). For example, we expect that understanding the BChl fast fluorescence transients can help to establish a clear view of the similar phases of Chl a fluorescence (OJIP) in higher plants: how they are affected by numerous reported factors including the photochemical and photoelectrochemical quenching (Vredenberg et al 2009), the redox states of the donor and acceptor sides of Photosystem II and PQ pool, conformational changes of the PS II RC or the influence of Photosystem I (Tóth 2006;Rappaport et al 2007;Tóth et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Kinetic bacteriochlorophyll fluorometer

et al. 2010

Self Cite

View full text Add to dashboard Cite

A pump and probe fluorometer with a laser diode as single light source has been constructed for measurement of fast induction and relaxation of the fluorescence yield in intact cells, chromatophores and isolated reaction centers of photosynthetic bacteria. The time resolution of the fluorometer is limited by the repetition time of the probing flashes to 20 micros. The apparatus offers high sensitivity, excellent performance and can become a versatile device for a range of demanding applications. Some of them are demonstrated here including fast and easy investigation of the (1) organization and redox state of the photosynthetic apparatus of the intact cells of different bacterial strains and mutants and (2) electron transfer reactions on donor and acceptor sides of isolated reaction centers. The compact design of the mechanics, optics, electronics, and data processing makes the device easy to use as outdoor instrument or to integrate into larger measuring systems.

show abstract

“…The mercury decreases the P+ to reduced cyt c2 stoichiometric excess, and, perhaps, might have some effects on the structural arrangement of the proteins, as well. DL of the RC bacteriochlorophyll dimer is used to measure the free energy state and the lifetime of the P+QA -charge separated state (Turzó et al 2000). After addition of mercury to the culture, a sudden decrease of the amplitude can be observed without major changes in the kinetics (Fig.…”

Section: Resultsmentioning

confidence: 99%

The reaction center is the sensitive target of the mercury(II) ion in intact cells of photosynthetic bacteria

et al. 2012

Self Cite

View full text Add to dashboard Cite

The sensitivity of intact cells of purple photosynthetic bacterium Rhodobacter sphaeroides wild type to low level (~100 µM) of mercury (Hg 2+ ) contamination was evaluated by absorption and fluorescence spectroscopies of the bacteriochlorophyll-protein complexes. All assays related to the function of the reaction center (RC) protein (induction of the bacteriochlorophyll fluorescence, delayed fluorescence and light-induced oxidation and reduction of the bacteriochlorophyll dimer and energization of the photosynthetic membrane) showed prompt and later effects of the mercury ions. The damage expressed by decrease of the magnitude and changes of rates of the electron transfer kinetics followed complex (spatial and temporal) pattern according to the different Hg 2+ sensitivities of the electron transport (donor/acceptor) sites including the reduced bound and free cytochrome c2 and the primary reduced quinone. In contrast to the RC, the light harvesting system and the bc1 complex demonstrated much higher resistance against the mercury pollution. The 850 and 875 nm components of the peripheral and core complexes were particularly insensitive to the mercury(II) ions. The concentration of the photoactive RCs and the connectivity of the photosynthetic units decreased upon mercury treatment. The degree of inhibition of the photosynthetic apparatus was always higher when the cells were kept in the light than in the dark indicating the importance of metabolism in active transport of the mercury ions from outside to the intracytoplasmic membrane. Any of the tests applied in this study can be used for detection of changes in photosynthetic bacteria at the early stages of the action of toxicants.

show abstract

Quinone-Dependent Delayed Fluorescence from the Reaction Center of Photosynthetic Bacteria

Cited by 31 publications

References 49 publications

A Photovoltaic Device Using an Electrolyte Containing Photosynthetic Reaction Centers

A Photovoltaic Device Using an Electrolyte Containing Photosynthetic Reaction Centers

Kinetic bacteriochlorophyll fluorometer

The reaction center is the sensitive target of the mercury(II) ion in intact cells of photosynthetic bacteria

Contact Info

Product

Resources

About