Massive Inorganic Carbon Cycling in Cyanobacteria Geared to the Energy Transfer to PSII

Tchernov, Dan; Keren, Nir; Hess, Matthew; Ronen-Tarazi, Michal; Luz, Boaz

doi:10.1007/978-94-011-3953-3_799

Cited by 1 publication

(5 citation statements)

References 8 publications

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“…In previous publications related to ICC, strongly buffered cultivation media with slightly alkaline pH was used . In our simulations, we considered two scenarios: a highly buffered system (

c_{B}^{t o t}

= 17 mM ), but also a weakly buffered system (

c_{B}^{t o t}

= 1 µM). In dark, we assumed excretion of both dCO 2 and

{HCO}_{3}^{-}

from the cells to the cultivation media due to dark respiration.…”

Section: Resultsmentioning

confidence: 99%

“…Although ICC has been first described already in 1998 , available methods used for ICC detection still rely on experimental evaluations of the dCO 2 displacement at the beginning and at the end of the light phase (Figure ). However, as we show in the simulations, in highly‐buffered cultivation media, such dCO 2 displacement can be observed even in the absence of ICC (Figures ).…”

Section: Discussionmentioning

confidence: 99%

“…For the validation of our numerical simulations of the dCO 2 and pH displacements under varying pH levels and buffer concentrations, we performed a series of Dark-Light-Dark experiments. High magnitudes of the dCO 2 displacement under high buffer concentration are well documented in the literature [2,21,34,36,39,40]. Therefore, in this work, we focused on the experimental validation of ICC visibility in more natural, weakly buffered systems.…”

Section: Experimental Validation Of the Model Predictionsmentioning

confidence: 96%

“…In both simulations and experiments, we focused on slightly acidic to slightly alkaline pH range, since first, with pH increase, the pH displacement becomes hardly detectable even in non-buffered systems due to (self-) buffering capacity of the carbonate system, Figure 3A-C, Figure 6), and second, at pH < 6, dCO 2 uptake can become significantly reduced or even inhibited [34]. Although ICC has been first described already in 1998 [21], available methods used for ICC detection still rely on experimental evaluations of the dCO 2 displacement at the beginning and at the end of the light phase (Figure 1). However, as we show in the simulations, in highly-buffered cultivation media, such dCO 2 displacement can be observed even in the absence of ICC (Figures 4 and 5).…”

Section: Detection Of Inorganic Carbon Cyclingmentioning

confidence: 99%

“…mechanisms, sudden energy income can cause irreversible destruction of the photosynthetic apparatus. Photosynthetic organisms developed several strategies for the dissipation of excessive light energy such as adjustments of light-harvesting antennas, thermal energy dissipation, photo-protective adjustments of the electron transport chain, reactive oxygen species scavenging [15][16][17][18][19][20], and also light-dependent "futile" inorganic carbon cycling (ICC) between cells and their aquatic environment [2,21].…”

mentioning

confidence: 99%

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Towards a quantitative assessment of inorganic carbon cycling in photosynthetic microorganisms

Müller

Zavřel

Červený

2019

Engineering in Life Sciences

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Photosynthetic organisms developed various strategies to mitigate high light stress. For instance, aquatic organisms are able to spend excessive energy by exchanging dissolved CO2 (dCO2) and bicarbonate (HCO3−) with the environment. Simultaneous uptake and excretion of the two carbon species is referred to as inorganic carbon cycling. Often, inorganic carbon cycling is indicated by displacements of the extracellular dCO2 signal from the equilibrium value after changing the light conditions. In this work, we additionally use (i) the extracellular pH signal, which requires non‐ or weakly‐buffered medium, and (ii) a dynamic model of carbonate chemistry in the aquatic environment to detect and quantitatively describe inorganic carbon cycling. Based on simulations and experiments in precisely controlled photobioreactors, we show that the magnitude of the observed dCO2 displacement crucially depends on extracellular pH level and buffer concentration. Moreover, we find that the dCO2 displacement can also be caused by simultaneous uptake of both dCO2 and HCO3− (no inorganic carbon cycling). In a next step, the dynamic model of carbonate chemistry allows for a quantitative assessment of cellular dCO2, HCO3−, and H+ exchange rates from the measured dCO2 and pH signals. Limitations of the method are discussed.

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“…In previous publications related to ICC, strongly buffered cultivation media with slightly alkaline pH was used . In our simulations, we considered two scenarios: a highly buffered system (