Characterization of Photosystem II Activity and Heterogeneity during the Cell Cycle of the Green Alga<i>Scenedesmus quadricauda</i>1

Kaftan, David; Mészáros, T.; Whitmarsh, John; Nedbal, Ladislav

doi:10.1104/pp.120.2.433

Cited by 46 publications

(35 citation statements)

References 45 publications

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“…Oxygen evolution was measured as one molecule of the pigment chlorophyll absorbs one photon and uses its energy to generate NADPH, ATP and O 2 via the lightdependent reactions (Kaftan et al, 1999). The oxygen evolution rates in Cyanothece 51142 rose by two-to threefold under all nitrate-sufficient conditions compared with corresponding nitrogen-fixation conditions (Fig.…”

Section: Photosynthesis Activitymentioning

confidence: 99%

Mixotrophic and photoheterotrophic metabolism in Cyanothece sp. ATCC 51142 under continuous light

et al. 2010

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The unicellular diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 (Cyanothece 51142) is able to grow aerobically under nitrogen-fixing conditions with alternating light-dark cycles or continuous illumination. This study investigated the effects of carbon and nitrogen sources on Cyanothece 51142 metabolism via 13 C-assisted metabolite analysis and biochemical measurements. Under continuous light (50 mmol photons m "2 s "1 ) and nitrogen-fixing conditions, we found that glycerol addition promoted aerobic biomass growth (by twofold) and nitrogenasedependent hydrogen production [up to 25 mmol H 2 (mg chlorophyll) "1 h "1 ], but strongly reduced phototrophic CO 2 utilization. Under nitrogen-sufficient conditions, Cyanothece 51142 was able to metabolize glycerol photoheterotrophically, and the activity of light-dependent reactions (e.g. oxygen evolution) was not significantly reduced. In contrast, Synechocystis sp. PCC 6803 showed apparent mixotrophic metabolism under similar growth conditions. Isotopomer analysis also detected that Cyanothece 51142 was able to fix CO 2 via anaplerotic pathways, and to take up glucose and pyruvate for mixotrophic biomass synthesis. INTRODUCTIONRising concerns about global warming due to the greenhouse effect have renewed research focused on the biological capture of CO 2 . Cyanobacteria have versatile metabolic capabilities, which allow them to grow under autotrophic, heterotrophic and mixotrophic conditions (Bottomley & Van Baalen, 1978;Eiler, 2006;Yang et al., 2002). More importantly, some cyanobacteria can capture solar energy to fix nitrogen and generate H 2 , thereby serving as a source of biofertilizer and biofuel, while simultaneously consuming atmospheric CO 2 (Bernat et al., 2009;Dutta et al., 2005;Fay, 1992;Madamwar et al., 2000;Tamagnini et al., 2007;Tuli et al., 1996). Cyanothece sp. ATCC 51142 (Cyanothece 51142), a unicellular diazotrophic cyanobacterium, is able to grow aerobically under nitrogen-fixing conditions and has been recognized as contributing to the marine nitrogen cycle. The recent sequencing of the Cyanothece 51142 genome and its transcriptional analysis have uncovered the diurnally oscillatory metabolism of the bacterium in alternating light-dark cycles (photosynthesis during the day and nitrogen fixation at night) (Stöckel et al., 2008;Toepel et al., 2008;Welsh et al., 2008). In general, cyanobacteria use spatial or temporal separation of oxygen-sensitive nitrogen fixation and oxygen-evolving photosynthesis as a strategy for diazotrophic growth (Benemann & Weare, 1974;Fay, 1992). Interestingly, Cyanothece 51142 demonstrates simultaneous N 2 fixation and O 2 evolution under continuous-light conditions, though it appears to be unicellular (Colon-Lopez et al., 1997;Huang & Chow, 1986). For example, a recent study of the transcriptional and translational regulation of continuously illuminated Cyanothece has revealed a strong synthesis capability for nitrogenase and circadian expression of 10 % of its genes (Toepel et al., 2008). Furthermore, Cyanothece str...

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Section: Photosynthesis Activitymentioning

confidence: 99%

Mixotrophic and photoheterotrophic metabolism in Cyanothece sp. ATCC 51142 under continuous light

et al. 2010

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“…Measurements of the electron-transport capacity of the PSII reaction center reveal two distinct populations, active PSII (PSII A ) and inactive PSII (PSII X ) centers (47). In PSII A centers, the oxidation of Q A Ϫ is fast (occurring in a few milliseconds or less), while in PSII X centers, the oxidation of Q A Ϫ is much slower (48). We analyzed the fluorescence decay curves induced by a series of single-turnover flashes to determine the proportions of PSII X and PSII A in whole cells.…”

mentioning

confidence: 99%

The Acceptor Side of Photosystem II Is the Initial Target of Nitrite Stress in Synechocystis sp. Strain PCC 6803

Zhang

Zhu

et al. 2017

Appl Environ Microbiol

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Nitrite, a common form of inorganic nitrogen (N), can be used as a nitrogen source through N assimilation. However, high levels of nitrite depress photosynthesis in various organisms. In this study, we investigated which components of the photosynthetic electron transfer chain are targeted by nitrite stress in Synechocystis sp. strain PCC 6803 cells. Measurements of whole-chain and photosystem II (PSII)-mediated electron transport activities revealed that high levels of nitrite primarily impair electron flow in PSII. Changes in PSII activity in response to nitrite stress occurred in two distinct phases. During the first phase, which occurred in the first 3 h of nitrite treatment, electron transfer from the primary quinone acceptor (Q A ) to the secondary quinone acceptor (Q B ) was retarded, as indicated by chlorophyll (Chl) a fluorescence induction, S-state distribution, and Q A Ϫ reoxidation tests. In the second phase, which occurred after 6 h of nitrite exposure, the reaction center was inactivated and the donor side of photosystem II was inhibited, as revealed by changes in Chl fluorescence parameters and thermoluminescence and by immunoblot analysis. Our data suggest that nitrite stress is highly damaging to PSII and disrupts PSII activity by a stepwise mechanism in which the acceptor side is the initial target. IMPORTANCE In our previous studies, an alga-based technology was proposed to fix the large amounts of nitrite that are released from NO X -rich flue gases and proved to be a promising industrial strategy for flue gas NO X bioremediation (W. Chen et al., Environ Sci Technol 50:1620 -1627, https://doi.org/10.1021/ acs.est.5b04696; X. Zhang et al., Environ Sci Technol 48:10497-10504, 2014, https:// doi.org/10.1021/es5013824). However, the toxic effects of high concentrations of nitrite on algal cells remain obscure. The analysis of growth rates, photochemistry, and protein profiles in our study provides important evidence that the inhibition by nitrite occurs in two phases: in the first phase, electron transfer between Q A Ϫ and Q B is retarded, whereas in the second, the donor side of PSII is affected. This is an excellent example of investigating the "early" inhibitory effects (i.e., within the first 6 h) on the PSII electron transfer chain in vivo. This paper provides novel insights into the mechanisms of nitrite inhibition of photosynthesis in an oxygenic phototrophic cyanobacterium.

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“…Regardless of the strain studied and the method used, photosynthetic activity increases from the start of the cell cycle, rapidly reaches a maximum in the first part of the cycle, and then gradually decreases until the end of the cycle's light period. This pattern was observed for S. quadricauda by Kaftan et al (1999), for S. obliquus by Strasser et al (1999) and for Desmodesmus armatus by Tukaj et al (2003), but it is still not clear to what extent these photosynthetic changes depend on the phase of cell and/or chloroplast development.…”

Section: Introductionmentioning

confidence: 88%

Relationships between growth, development and photosynthetic activity during the cell cycle ofDesmodesmus armatus(Chlorophyta) in synchronous cultures

Matusiak-Mikulin

Tukaj

2006

European Journal of Phycology

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The ultrastructural changes observed under an electron microscope, growth and biomass production expressed as the dry matter:cell volume ratio (DM:CV), as well as the photosynthetic activity characterized by chlorophyll fluorescence, of Desmodesmus armatus have been monitored in a synchronized light:dark (14 h:10 h) regime cell cycle. The timing of the commitment points triggering the reproductive processes and their termination were characterized by the commitment and autospore release curves, respectively. During the light period, each cell attained three commitment points in the 3rd, 6th and 11th hour, which resulted in the formation of eight autospores released from the parent cell during the dark period of the cell cycle. The successive commitment points occurred at times when DM:CV reached extreme values. The maximum DM:CV in the middle of the light period (5-6 h) coincided with the maximum effective quantum efficiency of PS II (ÈPS II). At this time, bands of several thylakoids could be seen in some areas of chloroplast, which were closer to each other and more contrasted than in other phases of the cell cycle. The highest efficiency of PS II antennae (F (qP) increased slightly, whereas non-photochemical quenching (NPQ) rapidly decreased during the first 3 h of the cell cycle. The main contributor to NPQ was its energydependent component (qE). In the 11 th hour, cells started to accumulate starch grains and lipid droplets, which were partly (starch) or completely (lipids) utilized during the first few hours of the next cell cycle. In conjunction with the ultrastructural changes, two functionally different phases of the cell cycle could be distinguished: the vegetative (about 10 h) and the reproductive (about 4 h) phases, and the relationships between growth, reproduction and photosynthesis in the Desmodesmus cell cycle are discussed.

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Characterization of Photosystem II Activity and Heterogeneity during the Cell Cycle of the Green AlgaScenedesmus quadricauda1

Cited by 46 publications

References 45 publications

Mixotrophic and photoheterotrophic metabolism in Cyanothece sp. ATCC 51142 under continuous light

Mixotrophic and photoheterotrophic metabolism in Cyanothece sp. ATCC 51142 under continuous light

The Acceptor Side of Photosystem II Is the Initial Target of Nitrite Stress in Synechocystis sp. Strain PCC 6803

Relationships between growth, development and photosynthetic activity during the cell cycle ofDesmodesmus armatus(Chlorophyta) in synchronous cultures

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