Evidence for the contribution of pseudocyclic photophosphorylation to the energy requirement of the mechanism for concentrating inorganic carbon in Chlamydomonas

Sültemeyer, Dieter; Biehler, Klaus; Fock, Heinrich P.

doi:10.1007/bf00195082

Cited by 47 publications

(38 citation statements)

References 32 publications

(68 reference statements)

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“…High pH can reduce algal photosynthetic ability and pigment content, because the dissolved CO 2 in water is limited (Axelsson et al 1999;Olischläger et al 2013). Meanwhile, the depletion of dissolved CO 2 stimulates ROS formation (Sültemeyer et al 1993). Compared to the NaCl stress, Na 2 CO 3 stress induced more ROS production and had more toxic effects on algal photosynthetic pigments and ability, which might be caused by the high pH.…”

Section: −mentioning

confidence: 99%

“…It has been reported that high pH reduces algal photosynthetic ability and pigment content, because it limits dissolved CO 2 -concentration in water (Axelsson et al 1999;Olischläger et al 2013). The depletion of dissolved Effects of NaCl and Na2CO3 stresses 1315 CO 2 can stimulate ROS formation, increase antioxidant enzyme activity (Sültemeyer et al 1993) and even induce PCD (Vardi et al 1999). In our previous study, we found that Na 2 CO 3 stress can increase the emission of VOCs from Chlamydomonas reinhardtii (Zuo et al 2012a).…”

Section: Introductionmentioning

confidence: 99%

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Effects of NaCl and Na2CO3 stresses on photosynthetic ability of Chlamydomonas reinhardtii

et al. 2014

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Chloride and carbonate salts are the main salts causing salinization and widely exist in aquatic environment, so algae may suffer from salinization stress for high water evaporation. In this study, in order to investigate and compare the toxic effects of the two salts on algal photosynthesis, we used NaCl and Na2CO3 to stress Chlamydomonas reinhardtii. Under the two salt stresses, the content of O −.2 and H2O2 in the cells was increased significantly, and it was much higher in Na2CO3 treatment than in NaCl treatment at the same Na + concentration. The absorbance spectra and 4 th derivative spectra of photosynthetic pigments were declined under 300 mM NaCl and 25 mM Na2CO3 stresses, and remarkably changed under 50 mM and 100 mM Na2CO3 stresses. When the cells stressed by the two salts, the maximum quantum yield (Fv/Fm), electron transport rate (ETR) and photochemical quenching (qP) were reduced markedly, but the nonphotochemical dissipation (NPQ) was increased markedly. At the same Na + concentration, Na2CO3 stress had stronger toxic effects on photosynthetic ability than NaCl stress.

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Section: −mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of NaCl and Na2CO3 stresses on photosynthetic ability of Chlamydomonas reinhardtii

et al. 2014

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“…Bicarbonate accumulation in the cytoplasm is thought to have an ATP : HCO K 3 or NADH : CO 2 cost ratio of 1 (but see Ritchie et al 1996). This ATP demand for CCM operation can be supplied directly by thylakoid pathways described in §5 (figure 6), including the pseudocyclic pathway (Mehler; Miller et al 1988;Sü ltemeyer et al 1993). Rubisco levels are also elevated under low CO 2 conditions to overcome slow catalytic rates (Tortell et al 2000), representing an additional resource cost to the cell.…”

Section: Nutrientsmentioning

confidence: 99%

Evolved physiological responses of phytoplankton to their integrated growth environment

Behrenfeld

Halsey

Milligan

2008

Phil. Trans. R. Soc. B

183

159

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Phytoplankton growth and productivity relies on light, multiple nutrients and temperature. These combined factors constitute the 'integrated growth environment'. Since their emergence in the Archaean ocean, phytoplankton have experienced dramatic shifts in their integrated growth environment and, in response, evolved diverse mechanisms to maximize growth by optimizing the allocation of photosynthetic resources (ATP and NADPH) among all cellular processes. Consequently, co-limitation has become an omnipresent condition in the global ocean. Here we focus on evolved phytoplankton populations of the contemporary ocean and the varied energetic pathways they employ to solve the optimization problem of resource supply and demand. Central to this discussion is the allocation of reductant formed through photosynthesis, which we propose has the following three primary fates: carbon fixation, direct use and ATP generation. Investment of reductant among these three sinks is tied to cell cycle events, differentially influenced by specific forms of nutrient stress, and a strong determinant of relationships between light-harvesting (pigment), photosynthetic electron transport and carbon fixation. Global implications of optimization are illustrated by deconvolving trends in the 10-year global satellite chlorophyll record into contributions from biomass and physiology, thereby providing a unique perspective on the dynamic nature of surface phytoplankton populations and their link to climate.

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“…Gross Oxygen Evolution and Oxygen Uptake-Gross oxygen evolution and oxygen uptake was measured at 25°C using a system described previously (39). Actinic light was provided by a slide projector (Braun) with heat filter.…”

Section: Sds-page and Westernmentioning

confidence: 99%

Limitation in Electron Transfer in Photosystem I Donor Side Mutants of Chlamydomonas reinhardtii

Hippler¹,

Biehler²,

Krieger‐Liszkay³

et al. 2000

Journal of Biological Chemistry

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Strains of Chlamydomonas reinhardtii lacking thePsaF gene or containing the mutation K23Q within the N-terminal part of PsaF are sensitive to high light (>400 E m ؊2 s ؊1 ) under aerobic conditions. In vitro experiments indicate that the sensitivity to high light of the isolated photosystem I (PSI) complex from wild type and from PsaF mutants is similar. In vivo measurements of photochemical quenching and oxygen evolution show that impairment of the donor side of PSI in the PsaF mutants leads to a diminished linear electron transfer and/or a decrease of photosystem II (PSII) activity in high light. Thermoluminescence measurements indicate that the PSII reaction center is directly affected under photo-oxidative stress when the rate of electron transfer becomes limiting in the PsaF-deficient strain and in the PsaF mutant K23Q. We have isolated a high light-resistant PsaF-deficient suppressor strain that has a high chlorophyll a/b ratio and is affected in the assembly of light-harvesting complex. These results indicate that under high light a functionally intact donor side of PSI is essential for protection of C. reinhardtii against photo-oxidative damage when the photosystems are properly connected to their light-harvesting antennae.Photosynthesis is driven by light. Photons are absorbed by pigments of the light harvesting chlorophyll-carotenoid-protein complexes that are associated with the membrane embedded photosynthetic reaction centers. Excitation energy can be transferred to the reaction centers where it induces charge separation across the membrane. This leads to a series of electron transfer reactions resulting in oxidation of water and the production of chemical energy in the form of ATP and NADPH, which are used for CO 2 fixation. If the absorption of light exceeds the capacity of photosynthetic energy consumption, over-reduction of the electron transport carriers and increase of the lifetime of excited states in the light-harvestingantennae occur. Over-reduction of the electron carriers can lead to photo-oxidative damage by reactive oxygen species. O 2 can be directly reduced by PSI 1 (1) generating superoxide anion radical (O 2 . ) and other reactive oxygen species. Increase in the lifetime of excited singlet chlorophyll increases the probability of triplet chlorophyll formation, which can react with O 2 to produce 1 O 2 (2, 3). Reactive oxygen species cause photo-oxidative damage, especially to PSII, which is considered to be the primary target for photoinhibition (4 -6). Thus, mechanisms that balance energy input through photochemistry with energy consumption through CO 2 assimilation and other metabolic pathways are essential for plant survival.Mechanisms that balance energy input and consumption can be divided into short and long term responses. Short term responses include nonphotochemical dissipation of excess energy (7, 8) and reduction of energy transfer to PSII through state transition, a process that leads to a redistribution of excitation energy to PSI by a reorganization of the antennae (...

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Evidence for the contribution of pseudocyclic photophosphorylation to the energy requirement of the mechanism for concentrating inorganic carbon in Chlamydomonas

Cited by 47 publications

References 32 publications

Effects of NaCl and Na2CO3 stresses on photosynthetic ability of Chlamydomonas reinhardtii

Effects of NaCl and Na2CO3 stresses on photosynthetic ability of Chlamydomonas reinhardtii

Evolved physiological responses of phytoplankton to their integrated growth environment

Limitation in Electron Transfer in Photosystem I Donor Side Mutants of Chlamydomonas reinhardtii

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