The Oscillation of Photosynthetic Capacity in <i>Lingulodinium polyedrum</i> is not related to differences in RuBisCo, Peridinin or Chlorophyll <i>a</i> Amounts

Hollnagel, Heloisa Candia; Pinto, Ernani; Morse, David; Colepicolo, Pio

doi:10.1076/brhm.33.4.443.8804

Cited by 15 publications

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“…In the dinoflagellate Amphidinium carterae , each holoprotein in the soluble trimeric peridinin‐chlorophyll‐protein complex contains four peridinin molecules and one chl. The three‐dimensional structure of this complex facilitates an efficient excitonic energy transfer from peridinin to chl (Hofmann et al 1996, Hollnagel et al 2002). Like ß‐carotene, peridinin can also suppress electronically excited molecules such as O 2 ( 1 Δ g ), which has been shown to be capable of inducing DNA damage and to be mutagenic (Di Mascio et al 1990, Hollnagel et al 1996).…”

Section: Ros and Oxidative Stressmentioning

confidence: 99%

HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE¹

Pinto

Sigaud-Kutner

Leitão

et al. 2003

Journal of Phycology

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Heavy metals, depending on their oxidation states, can be highly reactive and, as a consequence, toxic to most organisms. They are produced by an expanding variety of anthropogenic sources suggesting an increasingly important role for this form of pollution. The toxic effect of heavy metals appears to be related to production of reactive oxygen species (ROS) and the resulting unbalanced cellular redox status. Algae respond to heavy metals by induction of several antioxidants, including diverse enzymes such as superoxide dismutase, catalase, glutathione peroxidase and ascorbate peroxidase, and the synthesis of low molecular weight compounds such as carotenoids and glutathione. At high, or acute, levels of metal pollutants, damage to algal cells occurs because ROS levels exceed the capacity of the cell to cope. At lower, or chronic, levels algae accumulate heavy metals and can pass them on to organisms of other trophic levels such as mollusks, crustaceans, and fishes. We review here the evidence linking metal accumulation, cellular toxicity, and the generation of ROS in aquatic environments.

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Section: Ros and Oxidative Stressmentioning

confidence: 99%

HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE¹

Pinto

Sigaud-Kutner

Leitão

et al. 2003

Journal of Phycology

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939

450

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“…Both these different rhythms correlate with rhythms in the rate of protein synthesis in vivo , indicating that clock control over gene expression may regulate the timing of the rhythms. Importantly, in these and other examples, the control over protein synthesis occurs at a translational level since levels of the corresponding mRNAs do not change over the daily cycle [ 9 , 11 - 13 ].…”

Section: Introductionmentioning

confidence: 99%

The Lingulodinium circadian system lacks rhythmic changes in transcript abundance

Roy

Beauchemin

Dagenais-Bellefeuille

et al. 2014

BMC Biol

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BackgroundAlmost all cells display circadian rhythms, approximately 24-hour period changes in their biochemistry, physiology or behavior. These rhythms are orchestrated by an endogenous circadian clock whose mechanism is based on transcription-translation feedback loops (TTFL) where the translated products of clock genes act to inhibit their own transcription.ResultsWe have used RNA-Seq to measure the abundance of all transcripts in an RNA-Seq-derived de novo gene catalog in two different experiments. One compared midday and midnight in a light–dark cycle (ZT6 and ZT18) and under constant light (CT6 and CT18). The second compared four different times (ZT2, ZT6, ZT14 and ZT18) under a light dark cycle. We show here that despite an elaborate repertoire of biological rhythms, the unicellular dinoflagellate Lingulodinium had no detectable daily variation in the abundance of any transcript in an RNA-Seq-derived de novo gene catalog. We also examined the timing of the bioluminescence and photosynthesis rhythms in the presence of the transcription inhibitors actinomycin D and cordycepin. We found that the timing of the two rhythms was unchanged even when transcription rates had decreased to roughly 5% the levels of untreated cells.ConclusionsThe lack of detectable daily variation in transcript levels indicates that the endogenous circadian timer of Lingulodinium does not require rhythmic RNA. If the circadian timer is considered as a limit cycle oscillator, then cellular time in this organism must be defined by variations in state variables that do not include the amount of a clock gene transcript.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-014-0107-z) contains supplementary material, which is available to authorized users.

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“…To cause the rhythm, the circadian clock must influence critical rate‐limiting steps in the photosynthetic mechanism, and the identification of these key steps is a prerequisite to understanding clock control. It was initially thought that changing Rubisco levels might regulate photosynthetic electron flow by regulating reductant flow into carbon fixation, but numerous studies have confirmed that both the amounts and the activity of Rubisco are constant over the circadian cycle (Bush & Sweeney 1972; Nassoury, Fritz & Morse 2001; Hollnagel et al . 2002).…”

Section: Introductionmentioning

confidence: 99%

Circadian photosynthetic reductant flow in the dinoflagellate Lingulodinium is limited by carbon availability

MacKenzie

Morse

2011

Plant Cell & Environment

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Circadian rhythms are the observed outputs of endogenous daily clocks and are thought to provide a selective advantage to cells adapted to daily light/dark cycles. However, the biochemical links between the clock and the overt rhythms in cell physiology are generally not known. Here, we examine the circadian rhythm in O₂ evolution by cultures of the dinoflagellate Lingulodinium, a rhythm previously ascribed to rhythmic electron flow through photosystem II. We find that O₂ evolution rates increase when CO₂ concentrations are increased, either following addition of DIC or a rapid decrease in culture pH. In medium containing only nitrate as an electron acceptor, O₂ evolution rates mirror the circadian rhythm of nitrate reductase activity in the cells. Furthermore, competition between photosynthetic electron flow to carbon and to nitrate varies in its relative efficiency through the day-night cycle. We also find, using simultaneous and continuous monitoring of pH and O₂ evolution rates over several days, that while culture pH is normally rhythmic, circadian changes in rates of O₂ evolution depend not on the external pH but on levels of internal electron acceptors. We propose that the photosynthetic electron transport rhythm in Lingulodinium is driven by the availability of a reductant sink.

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The Oscillation of Photosynthetic Capacity in Lingulodinium polyedrum is not related to differences in RuBisCo, Peridinin or Chlorophyll a Amounts

Cited by 15 publications

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HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE¹

HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE¹

The Lingulodinium circadian system lacks rhythmic changes in transcript abundance

Circadian photosynthetic reductant flow in the dinoflagellate Lingulodinium is limited by carbon availability

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The Oscillation of Photosynthetic Capacity in Lingulodinium polyedrum is not related to differences in RuBisCo, Peridinin or Chlorophyll a Amounts

Cited by 15 publications

References 0 publications

HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE1

HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE1

The Lingulodinium circadian system lacks rhythmic changes in transcript abundance

Circadian photosynthetic reductant flow in the dinoflagellate Lingulodinium is limited by carbon availability

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HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE¹

HEAVY METAL–INDUCED OXIDATIVE STRESS IN ALGAE¹