Purine Biosynthetic Genes Are Required for Cadmium Tolerance in <i>Schizosaccharomyces pombe</i>

Speiser, David M.; Ortiz, Daniel; Kreppel, Lisa K.; Scheel, Günther; McDonald, Gregory A.; Ow, David W.

doi:10.1128/mcb.12.12.5301-5310.1992

Cited by 4 publications

(8 citation statements)

References 41 publications

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“…Genetic analyses of the link between metal complex accumulation and purine biosynthesis enzymes revealed that genetic lesions blocking two segments of the pathway, before and after the IMP branchpoint, are required to produce the Cd-sensitive phytochelatin-deficient phenotype in Schizosaccaromyces pombe . , …”

Section: Resultsmentioning

confidence: 99%

“…97,98 Genetic analyses of the link between metal complex accumulation and purine biosynthesis enzymes revealed that genetic lesions blocking two segments of the pathway, before and after the IMP branchpoint, are required to produce the Cdsensitive phytochelatin-deficient phenotype in Schizosaccaromyces pombe. 99,100 In Supplementary Figure 9 in the Supporting Information, we report the trends for a subset of metabolites involved in purine nucleoside metabolism, including adenine (Supplementary Figure 9.A in the Supporting Information), adenosine (B), cyclic AMP (C), AMP (D), ADP (E), sulfur-containing purines adenosyl-homocysteine (F), adenosylhomomethionine (G), hypoxanthine (H), IMP (I), and inosine (J). While hypoxanthine and related nucleoside were not apparently influenced by Cd stress, phosphorylated adenine nucleosides showed an increase upon Cd stress in comparison with untreated controls (Supplementary Figure 9.D,E in the Supporting Information).…”

Section: Journal Of Proteome Researchmentioning

confidence: 99%

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Cadmium Stress Responses inBrassica juncea: Hints from Proteomics and Metabolomics

et al. 2013

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Among heavy metal stressors, cadmium (Cd) pollution is one leading threat to the environment. In this view, research efforts have been increasingly put forward to promote the individuation of phytoextractor plants that are capable of accumulating and withstanding the toxic metals, including Cd, in the aerial parts. We hereby adopted the hyperaccumulator B. juncea (Indian mustard) as a model to investigate plant responses to Cd stress at low (25 μM) and high (100 μM) doses. Analytical strategies included mass-spectrometry-based determination of Cd and the assessment of its effect on the leaf proteome and metabolome. Results were thus integrated with routine physiological data. Taken together, physiology results highlighted the deregulation of photosynthesis efficiency, ATP synthesis, reduced transpiration, and the impairment of light-independent carbon fixation reactions. These results were supported at the proteomics level by the observed Cd-dependent alteration of photosystem components and the alteration of metabolic enzymes, including ATP synthase subunits, carbonic anhydrase, and enzymes involved in antioxidant responses (especially glutathione and phytochelatin homeostasis) and the Calvin cycle. Metabolomics results confirmed the alterations of energy-generating metabolic pathways, sulfur-compound metabolism (GSH and PCs), and Calvin cycle. Besides, metabolomics results highlighted the up-regulation of phosphoglycolate, a byproduct of the photorespiration metabolism. This was suggestive of the likely increased photorespiration rate as a means to cope with Cd-induced unbalance in stomatal conductance and deregulation of CO2 homeostasis, which would, in turn, promote CO2 depletion and O2 (and thus oxidative stress) accumulation under prolonged photosynthesis in the leaves from plants exposed to high doses of CdCl2. Overall, it emerges that Cd-stressed B. juncea might rely on photorespiration, an adaptation that would prevent the over-reduction of the photosynthetic electron transport chain and photoinhibition.

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Section: Resultsmentioning

confidence: 99%

Section: Journal Of Proteome Researchmentioning

confidence: 99%

Cadmium Stress Responses inBrassica juncea: Hints from Proteomics and Metabolomics

et al. 2013

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“…This background may have been advantageous. The ade6 þ gene product and other purine biosynthetic enzymes participate in the conversion of the PC-cadmium complex to the PC-cadmium-sulfide complex, which is essential for metal tolerance (Juang et al, 1993;Speiser et al, 1992). Therefore, the ade6-M210/216 allele potentially caused a synergistic effect with the additional gene deletion.…”

Section: Other Cellular Processesmentioning

confidence: 99%

“…Therefore, the ade6-M210/216 allele potentially caused a synergistic effect with the additional gene deletion. As an example, Speiser et al (1992) showed that either ade6-or ade2-disrupted mutants behaved like wild-type in the presence of cadmium, but the double mutant had inhibited growth. This effect was confirmed in our screen by the moderate sensitivity of ade2D, harboring the ade6-M216 allele (Table 1).…”

Section: Other Cellular Processesmentioning

confidence: 99%

A Genome-Wide Screen of Genes Involved in Cadmium Tolerance in Schizosaccharomyces pombe

Kennedy¹,

Vashisht²,

Hoe³

et al. 2008

Toxicological Sciences

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Cadmium is a worldwide environmental toxicant responsible for a range of human diseases including cancer. Cellular injury from cadmium is minimized by stress-responsive detoxification mechanisms. We explored the genetic requirements for cadmium tolerance by individually screening mutants from the fission yeast (Schizosaccharomyces pombe) haploid deletion collection for inhibited growth on agar growth media containing cadmium. Cadmium-sensitive mutants were further tested for sensitivity to oxidative stress (hydrogen peroxide) and osmotic stress (potassium chloride). Of 2649 mutants screened, 237 were sensitive to cadmium, of which 168 were cadmium specific. Most were previously unknown to be involved in cadmium tolerance. The 237 genes represent a number of pathways including sulfate assimilation, phytochelatin synthesis and transport, ubiquinone (Coenzyme Q10) biosynthesis, stress signaling, cell wall biosynthesis and cell morphology, gene expression and chromatin remodeling, vacuole function, and intracellular transport of macromolecules. The ubiquinone biosynthesis mutants are acutely sensitive to cadmium but only mildly sensitive to hydrogen peroxide, indicating that Coenzyme Q10 plays a larger role in cadmium tolerance than just as an antioxidant. These and several other mutants turn yellow when exposed to cadmium, suggesting cadmium sulfide accumulation. This phenotype can potentially be used as a biomarker for cadmium. There is remarkably little overlap with a comparable screen of the Saccharomyces cerevisiae haploid deletion collection, indicating that the two distantly related yeasts utilize significantly different strategies for coping with cadmium stress. These strategies and their relation to cadmium detoxification in humans are discussed.

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“…Most of the initial studies on the formation of CdS NCs by living yeasts were aimed at understanding the mechanisms of metal ion detoxification [82][83][84], although photochemical implications of NCs in living cells have also been discussed [70,71]. Evolution of H 2 S upon acidification of Cd-binding peptides from S. pombe was the first indication of the presence of CdS in these complexes [56,85,86].…”

Section: Synthesis Of Gsh-capped Ncsmentioning

confidence: 99%

Biomolecularly capped uniformly sized nanocrystalline materials: glutathione-capped ZnS nanocrystals

et al. 1999

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Micro-organisms such as bacteria and yeasts form CdS to detoxify toxic cadmium ions. Frequently, CdS particles formed in yeasts and bacteria were found to be associated with specific biomolecules. It was later determined that these biomolecules were present at the surface of CdS. This coating caused a restriction in the growth of CdS particles and resulted in the formation of nanometre-sized semiconductors (NCs) that exhibited typical quantum confinement properties. Glutathione and related phytochelatin peptides were shown to be the biomolecules that capped CdS nanocrystallites synthesized by yeasts Candida glabrata and Schizosaccharomyces pombe. Although early studies showed the existence of specific biochemical pathways for the synthesis of biomolecularly capped CdS NCs, these NCs could be formed in vitro under appropriate conditions. We have recently shown that cysteine and cysteine-containing peptides such as glutathione and phytochelatins can be used in vitro to dictate the formation of discrete sizes of CdS and ZnS nanocrystals. We have evolved protocols for the synthesis of ZnS or CdS nanocrystals within a narrow size distribution range. These procedures involve three steps: (1) formation of metallo-complexes of cysteine or cysteine-containing peptides, (2) introduction of stoichiometric amounts of inorganic sulfide into the metallo-complexes to initiate the formation of nanocrystallites and finally (3) size-selective precipitation of NCs with ethanol in the presence of Na+. The resulting NCs were characterized by optical spectroscopy, high-resolution transmission electron microscopy (HRTEM), x-ray diffraction and electron diffraction. HRTEM showed that the diameter of the ZnS-glutathione nanocrystals was 3.45±0.5 nm. X-ray diffraction and electron diffraction analyses indicated ZnS-glutathione to be hexagonal. Photocatalytic studies suggest that glutathione-capped ZnS nanocrystals prepared by our procedure are highly efficient in degrading a test model compound.

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Purine Biosynthetic Genes Are Required for Cadmium Tolerance in Schizosaccharomyces pombe

Cited by 4 publications

References 41 publications

Cadmium Stress Responses inBrassica juncea: Hints from Proteomics and Metabolomics

Cadmium Stress Responses inBrassica juncea: Hints from Proteomics and Metabolomics

A Genome-Wide Screen of Genes Involved in Cadmium Tolerance in Schizosaccharomyces pombe

Biomolecularly capped uniformly sized nanocrystalline materials: glutathione-capped ZnS nanocrystals

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