Dichromate effect on energy dissipation of photosystem II and photosystem I in Chlamydomonas reinhardtii

Perreault, François; Ali, Nadia; Saison, Cyril; Popovic, Radovan; Juneau, Philippe

doi:10.1016/j.jphotobiol.2009.03.011

Cited by 38 publications

(14 citation statements)

References 28 publications

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“…For the purpose, the wizard PEA built-in software FluorWin was used (Hill and Ralph 2008). OJIP fluorescence transients (Strasser and Govindjee 1992) were measured by applying a 6-s flash at the 80 % light intensity setting (>15×10 6 μmol photons (PAR) m −2 s −1 ) to a sample (cells taken from exponential phase of growth on day 6), dark-acclimated for at least 5 min (Perreault et al 2009). In order to standardize the results, the fluorescence values from the OJIP transients were normalized to the minimal fluorescence at the O step (50 μs) as described in Petrou et al (2011).…”

Section: Methodsmentioning

confidence: 99%

Impacts of nitrogen and phosphorus starvation on the physiology of Chlamydomonas reinhardtii

et al. 2015

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The importance of algae-derived biofuels has been highlighted by the current problems associated with fossil fuels. Considerable past research has shown that limiting nutrients such as nitrogen and phosphorus increases the cellular lipid content in microalgae. However, limiting the supply of nutrients results in decreased biomass, which in turn decreases the overall lipid productivity of cultures. Therefore, nutrient limitation has been a subject of dispute as to whether it will benefit biofuel production on an industrial scale. Our research explores the physiological changes a cell undergoes when exposed to nitrogen and phosphorus limitations, both individually and in combination, and also examines the biotechnological aspects of manipulating N and P in order to increase cellular lipids, by analyzing the lipid production. We show that nitrogen starvation and also nitrogen plus phosphorus starvation combined have a more profound effect on the physiology and macromolecular pools of Chlamydomonas reinhardtii than does phosphorus starvation alone. The photosynthetic performance of C. reinhardtii underwent drastic changes under nitrogen starvation, but remained relatively unaffected under phosphorus starvation. The neutral lipid concentration per cell was at least 2.4-fold higher in all the nutrient-starved groups than the nutrient-replete controls, but the protein level per cell was lower in the nitrogen-starved groups. Overall, nitrogen starvation has a more dramatic effect on the physiology and neutral lipids and protein levels of C. reinhardtii than phosphorus starvation. However, the level of total lipids per volume of culture obtained was similar among nutrient-replete and all of the nutrient-starved groups. We conclude that combined nitrogen and phosphorus starvation does not likely benefit biofuel production in terms of enhanced lipid or biomass production.

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Section: Methodsmentioning

confidence: 99%

Impacts of nitrogen and phosphorus starvation on the physiology of Chlamydomonas reinhardtii

et al. 2015

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“…The energy dissipation which was not used in PSII photochemistry was determined by fluorescence quenching effect using the ratio NPQ = (F M − F′ M )/F′ M (Bilger and Björkman 1990). For the evaluation of photosystem I (PSI) activity, a volume equivalent to 10×10 6 cells was filtered in a glass fiber prefilter and used for the measurement of P700 flash-induced transmittance change as in Perreault et al (2009). By using a Dual-PAM 100 (Walz), the maximal transmittance change induced by a short saturating flash (10,000 μmol photons m −2 s −1 , 0.3-s duration), indicating the amount of photochemically active PSI reaction center (ΔP700).…”

Section: Fluorescence Measurementsmentioning

confidence: 99%

Carotenoid production and change of photosynthetic functions in Scenedesmus sp. exposed to nitrogen limitation and acetate treatment

et al. 2011

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Under stress conditions, some microalgae upregulate certain biosynthetic pathways, leading to the accumulation of specific compounds. For example, changing nutrient composition can induce stress in algae's physiological activities, which may trigger an intense increase in carotenoid production. In this study, the change of photosynthetic functions and carotenoid production in the green microalga Scenedesmus sp. was investigated when algal cultures were exposed to conditions including limited nitrogen content with the addition of sodium acetate. Microalgal cultures were treated for 18 days under higher irradiance conditions. We observed a decrease of chlorophyll content induced concomitantly with a decline of photosystem II and I photochemistry. At the same time, an important increase in carotenoid content was detected. By using high-performance liquid chromatographic analysis, we found that the secondary carotenoids astaxanthin and canthaxanthin were accumulated compared to controls. During the process of carotenoid accumulation, chlorophyll degradation was found in addition to a strong decrease in photosynthetic electron transport. Such changes may be associated with the structural reorganization of the photosynthetic apparatus and can be a useful indicator of secondary carotenoid accumulation in algal cultures.

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“…The pulse-amplitude-modulation (PAM) fluorometric approach can provide useful information concerning photosynthetic electron transport and energy dissipation processes associated with PSII and PSI activity. Using the PAM approach, the yield of variable Chl a fluorescence as a measure of the PSII-PSI electron transport was frequently used to determine the toxic effects of metals and herbicides [18][19][20]. Parameters linked to PSII electron transport capacity (F V /F M , F V /F M ), photochemical energy dissipation (qP), and nonphotochemical quenching of fluorescence (qN, NPQ) are sensitive bioindicators of toxicity in plants and algae [14,21].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Copper Oxide Nanoparticles Toxicity Using Chlorophyll a Fluorescence Imaging in Lemna gibba

et al. 2010

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Copper oxide nanoparticles (CuO NPs), used in antifouling paints of boats, are released in the environment and can induce toxicity to aquatic organisms. In this report, we used chlorophyll a fluorescence imaging to evaluate CuO NPs toxicity in Lemna gibba. This approach allowed to evaluate the differential effect of CuO NPs on photosynthesis of whole L. gibba plants. Exposure to 0.1 to 0.4 g/L CuO NPs during 48h induced strong inhibition of photosynthetic processes resulting in a decrease of plant growth. By using fluorescence imaging, different photosynthetic parameters were evaluated simultaneously in microplate conditions. Imaging of F O fluorescence yield showed the decrease of leaf photosynthetic active surface for whole plants exposed to CuO NPs. This method showed that CuO NPs inhibited photosystem II maximal, photosystem II operational quantum yields, and photochemical quenching of fluorescence associated with electron transport. Nonphotochemical fluorescence quenching as an indicator of energy dissipation not used in photosynthesis was shown to be increased by the effect of CuO NPs. Such approach in microplate conditions provides synchronous high repetition measurements for numerous plants. This study may give a reliable methodological approach to evaluate toxicity risk of NPs in aquatic ecosystems.

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Dichromate effect on energy dissipation of photosystem II and photosystem I in Chlamydomonas reinhardtii

Cited by 38 publications

References 28 publications

Impacts of nitrogen and phosphorus starvation on the physiology of Chlamydomonas reinhardtii

Impacts of nitrogen and phosphorus starvation on the physiology of Chlamydomonas reinhardtii

Carotenoid production and change of photosynthetic functions in Scenedesmus sp. exposed to nitrogen limitation and acetate treatment

Evaluation of Copper Oxide Nanoparticles Toxicity Using Chlorophyll a Fluorescence Imaging in Lemna gibba

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