Biosynthesis of cadmium sulphide quantum semiconductor crystallites

Dameron, Charles T.; Reese, R. Neil; Mehra, Rajesh K.; Kortan, A. R.; Carroll, P; Steigerwald, Michael L.; Brus, L. E.; Winge, Dennis R.

doi:10.1038/338596a0

Cited by 769 publications

(391 citation statements)

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“…Various mechanisms have been proposed to account for the accumulation of these potentially toxic heavy metal ions in the plant vacuole (18,30). In general, these mechanisms include formation of soluble metal-organic acid complexes (4, 9, 14) or metal-phytate (25, 26), formation ofmetalpeptide or metal-peptide-sulfide complexes (9, 18, 27), or precipitation of metal-sulfides (2,21,25).Support for a particular mechanism of accumulation/sequestration of an ion is gained if the compartment of accumulation/sequestration is verified and if speciation of the ion in that compartment is determined. Both direct and indirect approaches (10) used to determine compartmentation ofions, including heavy metals, can only provide qualitative and quantitative estimates of vacuole contents (28).…”

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Computer-Simulated Evaluation of Possible Mechanisms for Quenching Heavy Metal Ion Activity in Plant Vacuoles

Wang¹,

Evangelou²,

Nielsen³

et al. 1991

Plant Physiol.

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Various mechanisms have been suggested for the quenching of Cd ion activity in plant vacuoles. These include solution complexation with organic acids and sulfhydryl-containing peptides and precipitation as sulfides. Because direct experimental support for these mechanisms is lacking and difficult to obtain, we have used a computer model to evaluate the quenching role of possible organic and inorganic ligands of tobacco cultured cells exposed to Cd. Results of this thermodynamic evaluation, which assumes that a chemical equilibrium state is met in the vacuole, support the conclusion that sulfhydryl-containing peptides and certain organic acids may form soluble Cd complexes. Although complexation of malate and oxalate with Cd is predicted to be less significant, citrate in the concentration range encountered in the tobacco cultured cell vacuoles has high potential for forming soluble complexes with Cd over the entire possible vacuolar pH range, especially 4.3 to 7.0, even in the presence of low levels of Cd-binding peptides. In addition, results show that inorganic chloride, sulfide (if present), and phosphate may also act to sequester Cd ion activity in the vacuole by forming soluble Cd-Cl and insoluble CdS and Cd-phosphate.Understanding the fate ofCd in plants is of interest because of concerns of Cd transfer from plants to animals and man. Recent studies suggest that heavy metals accumulated in the higher plant are mainly compartmentalized in the vacuole (5, 7, 9, 27). Various mechanisms have been proposed to account for the accumulation of these potentially toxic heavy metal ions in the plant vacuole (18,30). In general, these mechanisms include formation of soluble metal-organic acid complexes (4, 9, 14) or metal-phytate (25, 26), formation ofmetalpeptide or metal-peptide-sulfide complexes (9, 18, 27), or precipitation of metal-sulfides (2,21,25).Support for a particular mechanism of accumulation/sequestration of an ion is gained if the compartment of accumulation/sequestration is verified and if speciation of the ion in that compartment is determined. Both direct and indirect approaches (10) used to determine compartmentation ofions, including heavy metals, can only provide qualitative and quantitative estimates of vacuole contents (28). They cannot identify the species of ion complexes occurring in vacuoles. Therefore, mechanisms proposed on the basis of compartmentation analysis alone are not sufficient to argue the validity of a mechanism of accumulation/sequestration. However, it is possible with computer assistance to simulate the ion species distribution in the plant vacuole and thus to evaluate a proposed mechanism.Computer calculations have been used to model the chemistry of xylem sap of soybean and tomato (29). Here, we use data obtained previously regarding sap composition of vacuoles from Cd-treated tobacco (Nicotiana tabacum) cultured cells and the GEOCHEM-PC computer model (16,23) to predict ion species of these vacuoles in vivo. The prediction of ion speciation in vacuoles of Zn-treate...

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confidence: 99%

Computer-Simulated Evaluation of Possible Mechanisms for Quenching Heavy Metal Ion Activity in Plant Vacuoles

Wang¹,

Evangelou²,

Nielsen³

et al. 1991

Plant Physiol.

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“…The requirement for this additional form may be due to its altered properties relative to the LMW PC-Cd complex, including increased acid stability and an enhanced affinity for metals (25,27). PC-Cd-S-2 complexes from Candida glabrata have been shown to have electronic and optical properties different from bulk CdS (3,4). The HMW complex has not been a common feature in extracts from metalinduced plant cells, although Steffens et al (5,31) reported acid-labile S-2 and sulfite in PC-metal complexes isolated from tomato cells, and Verkleij et al (33) have reported increased levels of s2 in PC-Cd complexes from metalresistant isolates of Silene vulgaris.…”

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Brassica juncea Produces a Phytochelatin-Cadmium-Sulfide Complex

Speiser¹,

Abrahamson²,

Bañuelos³

et al. 1992

Plant Physiol.

106

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Phytochelatins (PCs) are enzymically synthesized peptides produced in higher plants and some fungi upon exposure to heavy metals. We have examined PC production in the Se-tolerant wild mustard Brassica juncea and found that it produces two types of PC-Cd complexes with the same characteristics as those from fission yeast Schizosaccharomyces pombe, including a high molecular weight PC-Cd-sulfide form.Heavy metals, a group of elements including Cd, Cu, Zn, Bi, Ni, Hg, and Pb, are toxic to all organisms at varying concentrations. In response to those elements, animal cells and some fungi, including Saccharomyces cerevisiae and Neurospora crassa, synthesize metal-chelating proteins called metallothioneins (11, 13). In contrast, the fission yeast Schizosaccharomyces pombe, algae, and higher plants synthesize enzymically produced peptides as a result of exposure to these metals. These metal-binding peptides have been called PC,2 cadystins, Cd-peptides, y(EC),-G, and y-glutamyl peptides; they will be referred to here, as in recent reviews (24,28,30), as PCs. PCs were first discovered in the fission yeast as components of metal-containing complexes from Cd-induced cells (19,20); it was demonstrated that previous reports of metallothionein-like proteins from plants could be attributed to PCs (9) and that PCs were produced by all higher plants tested (7). PCs have also been shown to exist in the algae Chlorella fusca (6) and the yeast Candida glabrata, which produces both PCs and a metallothionein (17,18). PC synthesis is induced by a variety of metals, including

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“…Yeast strains possess more benefits over bacteria because of their mass production of NPs and easy to control yeasts in laboratory circumstances, the synthesis of numerous enzymes and rapid growth with the use of simple nutrients [35] . It was also reported that with an employment of silver tolerant yeast strain MKY3, hexagonal silver nanoparticles (2-5 nm) were produced extracellularly [36] .…”

Section: Synthesis Of Nanoparticles From Yeastmentioning

confidence: 99%

A Brief Review on Nanoparticles: Types of Platforms, Biological Synthesis and Applications

Anwar¹

2018

Res. Rev. J Mat. Sci

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Biosynthesis of cadmium sulphide quantum semiconductor crystallites

Cited by 769 publications

References 20 publications

Computer-Simulated Evaluation of Possible Mechanisms for Quenching Heavy Metal Ion Activity in Plant Vacuoles

Computer-Simulated Evaluation of Possible Mechanisms for Quenching Heavy Metal Ion Activity in Plant Vacuoles

Brassica juncea Produces a Phytochelatin-Cadmium-Sulfide Complex

A Brief Review on Nanoparticles: Types of Platforms, Biological Synthesis and Applications

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