Oxygen Consumption: Photorespiration and Chlororespiration

Beardall, John; Quigg, Antonietta; Raven, John A.

doi:10.1007/978-94-007-1038-2_8

Cited by 47 publications

(36 citation statements)

References 89 publications

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“…However, we do not see a clear relationship between hydrogen isotope fractionation and light intensity. Due to balancing between ATP and NADPH production and consumption within the cell (Walker et al, 2014), NADPH formation dominates at high light levels, whereas ATP synthesis dominates at lower light levels (Beardall et al, 2003), leading to the idea that a larger pool of photosynthetically derived NADPH inside the cell under high light conditions would, in turn, cause differences in hydrogen isotope fractionation during the synthesis of alkenones, but this is not what the data show. Transhydrogenase enzyme activity can remove NADPH when in excess by reducing NAD+ to NADH using NADPH (Kim and Gadd, 2008;Zhang et al, 2009), which is associated with a large isotope fractionation effect of between 800 and 3500 ‰ (Zhang et al, 2009), leaving a relatively D-enriched pool of NADPH behind.…”

Section: Potential Mechanisms For Salinity and Light Responsesmentioning

confidence: 83%

“…Therefore, knowing these parameters is important to reconstruct ocean circulation in the geological past, which leads to a more robust understanding of our climate system. A number of valuable proxies exist to reconstruct sea surface temperature, for example, δ 18 O foram (Emiliani, 1955), Mg / Ca (Elderfield and Ganssen, 2000), TEX 86 (Schouten et al, 2002), U K 37 (Brassell et al, 1986), and long-chain diol index (Rampen et al, 2012). However, there are currently very few proxies for reconstructing sea surface salinity (SSS).…”

Section: Introductionmentioning

confidence: 99%

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Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

et al. 2017

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Abstract. Over the last decade, hydrogen isotopes of longchain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δD C 37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high-and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

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Section: Potential Mechanisms For Salinity and Light Responsesmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

et al. 2017

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“…This response is called RISE , and it might be the main driver of P700 oxidation under CO 2 limitation in cyanobacteria. Respiratory terminal oxidases like Cyt c oxidase and cytochrome bd-type quinol oxidase also may contribute to the oxidation of the donor side of PSI under CO 2 limitation (Beardall et al, 2003;Trouillard et al, 2012;Lea-Smith et al, 2013). It is difficult, however, to explain why Y(II) decreased during CO 2 limitation in the cyanobacteria we studied ( Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Second, plastidial terminal oxidase and cyanobacterial respiratory terminal oxidases on the thylakoid membranes suppress PSI electron influx by accepting upstream PSI electrons in the PET system. Oxygen is the final electron acceptor (Beardall et al, 2003;Trouillard et al, 2012;Lea-Smith et al, 2013). Finally, plastoquinol accumulation inhibits the Q-cycle turnover in the Cyt b 6 /f complex, which suppresses electron flow from the Cyt b 6 /f complex to P700.…”

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confidence: 99%

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

2016

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The photoinhibition of photosystem I (PSI) is lethal to oxygenic phototrophs. Nevertheless, it is unclear how photodamage occurs or how oxygenic phototrophs prevent it. Here, we provide evidence that keeping P700 (the reaction center chlorophyll in PSI) oxidized protects PSI. Previous studies have suggested that PSI photoinhibition does not occur in the two model cyanobacteria, Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942, when photosynthetic CO 2 fixation was suppressed under low CO 2 partial pressure even in mutants deficient in flavodiiron protein (FLV), which mediates alternative electron flow. The lack of FLV in Synechococcus sp. PCC 7002 (S. 7002), however, is linked directly to reduced growth and PSI photodamage under CO 2 -limiting conditions. Unlike Synechocystis sp. PCC 6803 and S. elongatus PCC 7942, S. 7002 reduced P700 during CO 2 -limited illumination in the absence of FLV, resulting in decreases in both PSI and photosynthetic activities. Even at normal air CO 2 concentration, the growth of S. 7002 mutant was retarded relative to that of the wild type. Therefore, P700 oxidation is essential for protecting PSI against photoinhibition. Here, we present various strategies to alleviate PSI photoinhibition in cyanobacteria.Low CO 2 fixation efficiency in the Calvin-Benson cycle prevents the utilization of NADPH and ATP in photosynthesis and causes these molecules to accumulate, resulting in oxidative photosynthetic cell damage. High light, low temperature, and CO 2 limitation increase NADPH and ATP levels beyond the Calvin-Benson cycle requirements. Electrons and H +

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“…A segregation between ETR and oxygenetic photosynthesis can be explained by state-transitions (Ihnken et al 2014 (Beardall et al 2003, Peterhansel & Maurino 2011 or mitochon drial respiration can cause deviation between fluorescence and oxygen based measurements.…”

Section: Ph-dependent Acclimation Patternsmentioning

confidence: 99%

Light acclimation and pH perturbations affect photosynthetic performance in Chlorella mass culture

Ihnken¹,

Beardall²,

Kromkamp³

et al. 2014

Aquat. Biol.

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Chlorella spp. are robust chlorophyte microalgal species frequently used in mass culture. The pH optimum for growth is close to neutrality; at this pH, theoretically little energy is required to maintain homeostasis. In the present study, we grew Chlorella fusca cells in an open, outdoor, thin-layer cascade photobioreactor (TLC), under ambient photon flux at the theoretically preferred pH (7.2), and let the culture pass the exponential growth phase. Using pH drift experiments, we show that an alkalization to pH 9 supported photosynthesis in the TLC. The increased photosynthetic activity under alkaline conditions was a pH-dependent effect, and not a dissolved inorganic carbon (DIC) concentration-or light intensity-dependent effect. Re-acidification (in one step or in increments) lowered gross oxygen production and increased non-photochemical quenching in short-term experiments. Gross oxygen production and electron transport rates in PSII were uncoupled during the pH perturbation experiments. Electron transport rates were only marginally affected by pH, whereas oxygen production rates decreased with acidification. Alternative electron pathways, electron donation at the plastid terminal oxidase and state-transitions are discussed as a potential explanation. Because cell material from the TLC was not operating at maximal capacity, we propose that alkalization can support photosynthesis in challenged TLC systems.

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Oxygen Consumption: Photorespiration and Chlororespiration

Cited by 47 publications

References 89 publications

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

Light acclimation and pH perturbations affect photosynthetic performance in Chlorella mass culture

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Oxygen Consumption: Photorespiration and Chlororespiration

Cited by 47 publications

References 89 publications

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by &lt;i&gt;Emiliania huxleyi&lt;/i&gt;

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by &lt;i&gt;Emiliania huxleyi&lt;/i&gt;

Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

Light acclimation and pH perturbations affect photosynthetic performance in Chlorella mass culture

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Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>