Response of nonprotein thiols to copper stress and extracellular release of glutathione in the diatom <i>Thalassiosira weissflogii</i>

Tang, D.; Shafer, Martin M.; Karner, Dawn A.; Armstrong, David E.

doi:10.4319/lo.2005.50.2.0516

Cited by 37 publications

(31 citation statements)

References 40 publications

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“…A glutathione-type ligand that has been implicated as a Cu ligand (Al-Farawati & van den Berg 1999, Leal et al 1999, Laglera & van den Berg 2003, Tang et al 2005, Laglera & van den Berg 2006, Marijić & Raspor 2007 was found in all 3 cultures. About 50% of natural marine Cu-complexing ligands have been found to belong to substances with a molecular weight between 1 and 10 kDa (Wells et al 1998, Wen et al 1999) which corresponds with molecular mass of glutathione and phytochelatins.…”

Section: Tep and Carbohydratesmentioning

confidence: 92%

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Characterization of phytoplankton exudates and carbohydrates in relation to their complexation of copper, cadmium and iron

Strmečki¹,

Plavšić²,

Steigenberger³

et al. 2010

Mar. Ecol. Prog. Ser.

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The goal of this study was to investigate if transparent exopolymer particles (TEP), carbohydrates, surface-active substances (SAS), reduced sulfur species (RSS), or thio/amino groups contribute significantly to the complexing capacity of phytoplankton exudates for Cu (L TOTCu ), Cd (L TOTCd ), or Fe (L TOTFe ). Complexing capacities and apparent stability constants (K app ) were determined electrochemically for Cu and Cd in cultures of the marine diatoms Thalassiosira weissflogii and Skeletonema costatum, and in a culture of the coccolithophore Emiliana huxleyi. Furthermore, the complexing capacity with Fe, Cu and Cd of 4 marine polysaccharides (PS) (phytagel, carrageenan, laminarin and alginic acid) was investigated. As expected, more Cu than Cd was complexed in the 3 phytoplankton cultures and in the phytagel solution. Size fractionation of the phytagel solution suggests that the binding capacity for Cu was more significant in the particulate fraction (> 0.7 µm), indicating that Cu was preferably trapped within pores and channels of large hydrogels. In contrast, Cd binding sites were predominantly found in the fraction < 0.7 µm, suggesting binding to the outer surfaces of gel particles to be of greater importance for larger ions. The K app of the Cd complexes were higher than those of Cu, indicating stronger binding of Cd ions than of Cu ions. Solutions of carrageenan, laminarin and alginic acid did not form complexes with either Cu or Cd, and Febinding properties could not be detected for any of the 4 polysaccharide solutions. Thio/amino groups of sulfur-rich 'glutathione' type ligands were found in all phytoplankton cultures and were presumably responsible for the complexation of Cu. No consistent relationship was observed between TEP, carbohydrate concentration, SAS or sulfur content, or with the complexing capacity, emphasizing the high degree of heterogeneity of substance classes responsible for metal binding.

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Section: Tep and Carbohydratesmentioning

confidence: 92%

“…Glutathione and other thiols are present in surface waters and are known to be released by phytoplankton, including Emiliana huxleyi (Dupont & Ahner 2005) and Thalassiosira weissflogii (Tang et al 2005) when exposed to elevated concentrations of Cu or Cd. However, the presence of the more complexed ligands, i.e.…”

Section: Concentrations Of Sulfur Speciesmentioning

confidence: 99%

Characterization of phytoplankton exudates and carbohydrates in relation to their complexation of copper, cadmium and iron

Strmečki¹,

Plavšić²,

Steigenberger³

et al. 2010

Mar. Ecol. Prog. Ser.

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“…For instance, liberation of glutathione by the diatom T. weissflogi (Tang et al, 2004(Tang et al, , 2005 or cysteine by E. huxleyi (Dupont et al, 2004;Dupont and Ahner, 2005) was found to increase in response to an increase of Cu in the medium. In response to a rise in Cu, Cd or Zn concentrations, exudation of arginine-cysteine, glutamine-cysteine, cysteine, glutathione or c-glutamate-cysteine by the coccolithophorid huxleyi have been recorded (Dupont and Ahner, 2005).…”

Section: Changes Observed In the Culture Media Of Different Algal Spementioning

confidence: 96%

Exudates of different marine algae promote growth and mediate trace metal binding in Phaeodactylum tricornutum

Vasconcelos

Leal

2008

Marine Environmental Research

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a b s t r a c tPhaeodactylum tricornutum was grown in filtered natural seawater enriched with nitrate, phosphate, and silicate only (control) or with exudates from itself, from Emiliania huxleyi (a coccolithophore micro-alga), Porphyra spp. (a red macro-alga) or Enteromorpha spp. (a green macro-alga). Cathodic (and anodic) stripping voltammetry (C(A)SV) were used to determine the concentrations of trace metals, both in the medium and in the algae, as well as total Cu-complexing organic ligands in the medium and, among these, some thiols (compounds identified as cysteine-or as glutathione by CSV). Exudates of different marine micro-and macro-algae could cause allelopathic effects in P. tricornutum cultures. Cell yield of P. tricornutum was increasingly promoted by exudates of E. huxleyi > Porphyra > Enteromorpha. Although exudates strongly complex Cu (and probably other metals), their presence promoted Cu uptake. Significant changes of Ni, Cd, Fe, Zn and Mn uptake by P. tricornutum were also observed in the presence of exudates of different algal species. In addition, both intensity of production and nature of exudates released by P. tricornutum were markedly influenced by the presence of exudates of other algae, the allelopathic effects being very specific (variable from one species to another). Allelopathy will probably also occur in the aquatic environment, although to a lesser extent than in cultures, particularly during bloom events and may have effects on both chemical speciation and bioavailability of chemicals to phytoplanktonic species. Such changes might cause the predominance of some species over other species. Therefore, in future in vitro culture studies with the purpose of using them as models of the real environment, more attention should be paid to the role of algal exudates, in order to improve the environmental relevance and significance of the results.

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“…Larger amino acid-containing molecules may be released by phytoplankton. For example, Thalassiosira weissflogii grown at several copper concentrations released the tripeptide glutathione (GSH) in response to copper-induced cell membrane damage (Tang et al, 2005). Emiliana huxleyi released thiols composed of the amino acids arginine, cysteine and glutamine in response to heavy metals (Dupont et al, 2004).…”

Section: Amino Acids and Proteinsmentioning

confidence: 99%

Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

Thornton

2014

European Journal of Phycology

368

311

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The partitioning of organic matter (OM) between dissolved and particulate phases is an important factor in determining the fate of organic carbon in the ocean. Dissolved organic matter (DOM) release by phytoplankton is a ubiquitous process, resulting in 2-50% of the carbon fixed by photosynthesis leaving the cell. This loss can be divided into two components: passive leakage by diffusion across the cell membrane and the active exudation of DOM into the surrounding environment. At present there is no method to distinguish whether DOM is released via leakage or exudation. Most explanations for exudation remain hypothetical; as while DOM release has been measured extensively, there has been relatively little work to determine why DOM is released. Further research is needed to determine the composition of the DOM released by phytoplankton and to link composition to phytoplankton physiological status and environmental conditions. For example, the causes and physiology of phytoplankton cell death are poorly understood, though cell death increases membrane permeability and presumably DOM release. Recent work has shown that phytoplankton interactions with bacteria are important in determining both the amount and composition of the DOM released. In response to increasing CO 2 in the atmosphere, climate change is creating increasingly stressful conditions for phytoplankton in the surface ocean, including relatively warm water, low pH, low nutrient supply and high light. As ocean physics and chemistry change, it is hypothesized that a greater proportion of primary production will be released directly by phytoplankton into the water as DOM. Changes in the partitioning of primary production between the dissolved and particulate phases will have bottom-up effects on ecosystem structure and function. There is a need for research to determine how these changes affect the fate of organic matter in the ocean, particularly the efficiency of the biological carbon pump.

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Response of nonprotein thiols to copper stress and extracellular release of glutathione in the diatom Thalassiosira weissflogii

Cited by 37 publications

References 40 publications

Characterization of phytoplankton exudates and carbohydrates in relation to their complexation of copper, cadmium and iron

Characterization of phytoplankton exudates and carbohydrates in relation to their complexation of copper, cadmium and iron

Exudates of different marine algae promote growth and mediate trace metal binding in Phaeodactylum tricornutum

Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

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