Genome-Wide Profiling of Responses to Cadmium in the Diatom <i>Phaeodactylum tricornutum</i>

Brembu, Tore; Jørstad, Margrethe; Winge, Per; Valle, Kristin Collier; Bones, Atle M.

doi:10.1021/es2002259

Cited by 52 publications

(29 citation statements)

References 53 publications

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“…Other works on P. tricornutum reported 10-30 fg cell 21 [45][46][47]; for a review, see [4]. In the presence of Cd, the intensity of qNi was reduced to the same extent as the DER (table 1) and was slowed down, suggesting that Cd could directly interact with DTE (see electronic supplementary material, Data S1).…”

Section: Resultsmentioning

confidence: 89%

Relaxation of the non-photochemical chlorophyll fluorescence quenching in diatoms: kinetics, components and mechanisms

Roháček

Bertrand

Moreau

et al. 2014

Phil. Trans. R. Soc. B

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Diatoms are especially important microorganisms because they constitute the larger group of microalgae. To survive the constant variations of the light environment, diatoms have developed mechanisms aiming at the dissipation of excess energy, such as the xanthophyll cycle and the non-photochemical chlorophyll (Chl) fluorescence quenching. This contribution is dedicated to the relaxation of the latter process when the adverse conditions cease. An original nonlinear regression analysis of the relaxation of non-photochemical Chl fluorescence quenching, qN, in diatoms is presented. It was used to obtain experimental evidence for the existence of three time-resolved components in the diatom Phaeodactylum tricornutum : qNf, qNi and qNs. qNf (s time-scale) and qNs (h time-scale) are exponential in shape. By contrast, qNi (min time-scale) is of sigmoidal nature and is dominant among the three components. The application of metabolic inhibitors (dithiothreitol, ammonium chloride, cadmium and diphenyleneiodonium chloride) allowed the identification of the mechanisms on which each component mostly relies. qNi is linked to the relaxation of the ΔpH gradient and the reversal of the xanthophyll cycle. qNs quantifies the stage of photoinhibition caused by the high light exposure, qNf seems to reflect fast conformational changes within thylakoid membranes in the vicinity of the photosystem II complexes.

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Section: Resultsmentioning

confidence: 89%

Relaxation of the non-photochemical chlorophyll fluorescence quenching in diatoms: kinetics, components and mechanisms

Roháček

Bertrand

Moreau

et al. 2014

Phil. Trans. R. Soc. B

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“…Shapes in the cluster indicate the localization of enzymes encoded by the gene: Triangle, mitochondria; Square, chloroplast; Diamond, peroxisome; Circle, no prediction. Transcription data of five microarray datasets from P. tricornutum submitted to GEO, NCBI (GSE12015, GSE17237, GSE31131, GSE42039 and GSE42514; [93,94,95,96,97]) were used to construct based on log2 expression ratios from the experiments, an unweighted co-expression network by using Cytoscape (version 2.8.3) and the force directed drawing algorithm [98]. The network represents 106 genes related to lipid metabolism with similar transcriptional profiles and includes 311 calculated gene-pairs with Pearson correlation values r > 0.85.…”

Section: Eicosapentaenoic Acid (Epa 20:5n-3) Synthesis In Phaedoamentioning

confidence: 99%

Pathways of Lipid Metabolism in Marine Algae, Co-Expression Network, Bottlenecks and Candidate Genes for Enhanced Production of EPA and DHA in Species of Chromista

et al. 2013

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The importance of n-3 long chain polyunsaturated fatty acids (LC-PUFAs) for human health has received more focus the last decades, and the global consumption of n-3 LC-PUFA has increased. Seafood, the natural n-3 LC-PUFA source, is harvested beyond a sustainable capacity, and it is therefore imperative to develop alternative n-3 LC-PUFA sources for both eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). Genera of algae such as Nannochloropsis, Schizochytrium, Isochrysis and Phaedactylum within the kingdom Chromista have received attention due to their ability to produce n-3 LC-PUFAs. Knowledge of LC-PUFA synthesis and its regulation in algae at the molecular level is fragmentary and represents a bottleneck for attempts to enhance the n-3 LC-PUFA levels for industrial production. In the present review, Phaeodactylum tricornutum has been used to exemplify the synthesis and compartmentalization of n-3 LC-PUFAs. Based on recent transcriptome data a co-expression network of 106 genes involved in lipid metabolism has been created. Together with recent molecular biological and metabolic studies, a model pathway for n-3 LC-PUFA synthesis in P. tricornutum has been proposed, and is compared to industrialized species of Chromista. Limitations of the n-3 LC-PUFA synthesis by enzymes such as thioesterases, elongases, acyl-CoA synthetases and acyltransferases are discussed and metabolic bottlenecks are hypothesized such as the supply of the acetyl-CoA and NADPH. A future industrialization will depend on optimization of chemical compositions and increased biomass production, which can be achieved by exploitation of the physiological potential, by selective breeding and by genetic engineering.

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“…Therefore, any information about substances that are capable of being transported through any of these mechanisms with silicic acid is useful in the understanding of biosilicification. The influence of heavy metals (mercury, cadmium, zinc) on diatoms had been studied in relation to environmental importance of these pollutants [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Toxicity of heavy metals is attributed usually to undesirable complexation with essential biomolecules, for example enzymes including competition with other metal ions.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Titanium, Zirconium and Tin on the Growth of Diatom Synedra Acus and Morphology of Its Silica Valves

Basharina

Danilovtseva

Zelinskiy

et al. 2012

Silicon

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The effect of three Group IV metals (titanium, zirconium and tin) on the growth, morphology and chemical composition of the freshwater diatom Synedra acus subsp. radians (Kützing) Skabichevsky was studied and compared with germanium. The elements in their highest oxidation states were introduced into the culture medium in the form of hydroxides. Germanium was found to be toxic at ≥5 mol. % of the total Ge-Si content in the culture medium. In the presence of other elements, a slight decrease in the cell division rate was observed independent of the element within 1-15% content interval. The analysis of the obtained biomass and silica valves revealed the presence of all the added elements within the cells. However, only germanium was incorporated into the valves in considerable amounts. S. acus cultivation with the addition of 5% Group IV elements resulted in cells having the following aberrations in the structure of the silica valves: changes in valve shape, thickening of valves, alterations of the areolae rows, irregularity or absence of the areolae and a decrease in the mechanical strength of valves. Moreover, the effect of Group IV elements on silica formation was simulated in vitro using a synthetic polymer bearing polyamine and phosphate groups found in silaffines (proteins from Electronic supplementary material The online version of this article (diatom frustules). The studied elements were observed to provoke the formation of unstable silica particles in solution. We propose that the observed effects of germanium, titanium, zirconium and tin on diatom growth and structure are due to uncontrollable silica condensation.

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Genome-Wide Profiling of Responses to Cadmium in the Diatom Phaeodactylum tricornutum

Cited by 52 publications

References 53 publications

Relaxation of the non-photochemical chlorophyll fluorescence quenching in diatoms: kinetics, components and mechanisms

Relaxation of the non-photochemical chlorophyll fluorescence quenching in diatoms: kinetics, components and mechanisms

Pathways of Lipid Metabolism in Marine Algae, Co-Expression Network, Bottlenecks and Candidate Genes for Enhanced Production of EPA and DHA in Species of Chromista

The Effect of Titanium, Zirconium and Tin on the Growth of Diatom Synedra Acus and Morphology of Its Silica Valves

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