Phytochelatins
Mostrando 13-24 de 42 artigos, teses e dissertações.
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13. Phytochelatins, the heavy-metal-binding peptides of plants, are synthesized from glutathione by a specific γ-glutamylcysteine dipeptidyl transpeptidase (phytochelatin synthase)
An enzyme has been discovered and characterized from Silene cucubalus cell suspension cultures that catalyzes the transfer of the γ-glutamylcysteine dipeptide moiety of glutathione to an acceptor glutathione molecule or a growing chain of [Glu(-Cys)]n-Gly oligomers, thus synthesizing phytochelatins, the metal-binding peptides of higher plants and select fun
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14. Synthesis of Phytochelatins and Homo-Phytochelatins in Pisum sativum L.
In the roots of pea plants (Pisum sativum L.) cultivated with 20 [mu]M CdCl2 for 3 d, synthesis of phytochelatins [PCs or ([gamma]EC)nG, where [gamma]EC is [gamma]glutamylcysteine and G is glycine] and homophytochelatins [h-PCs, ([gamma]EC)n[beta]-alanine] is accompanied by a drastic decrease in glutathione (GSH) content, but an increase in homoglutathione (
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15. AtPCS1, a phytochelatin synthase from Arabidopsis: Isolation and in vitro reconstitution
Phytochelatins, a class of posttranslationally synthesized peptides, play a pivotal role in heavy metal, primarily Cd2+, tolerance in plants and fungi by chelating these substances and decreasing their free concentrations. Derived from glutathione and related thiols by the action of γ-glutamylcysteine dipeptidyl transpeptidases (phytochelatin synthases; EC
The National Academy of Sciences.
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16. Detoxification of Arsenic by Phytochelatins in Plants1
As is a ubiquitous element present in the atmosphere as well as in the aquatic and terrestrial environments. Arsenite and arsenate are the major forms of As intoxication, and these anions are readily taken up by plants. Both anions efficiently induce the biosynthesis of phytochelatins (PCs) ([γ-glutamate-cysteine]n-glycine) in vivo and in vitro. The rapid i
American Society of Plant Physiologists.
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17. Phytochelatin production by marine phytoplankton at low free metal ion concentrations: laboratory studies and field data from Massachusetts Bay.
Phytochelatins are small metal-binding polypeptides synthesized by algae in response to high metal concentrations. Using a very sensitive HPLC method, we have quantified phytochelatins from phytoplankton in laboratory cultures at environmentally relevant metal concentrations and in marine field samples. Intracellular concentrations of phytochelatin, in the d
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18. Overexpression of Glutathione Synthetase in Indian Mustard Enhances Cadmium Accumulation and Tolerance1
An important pathway by which plants detoxify heavy metals is through sequestration with heavy-metal-binding peptides called phytochelatins or their precursor, glutathione. To identify limiting factors for heavy-metal accumulation and tolerance, and to develop transgenic plants with an increased capacity to accumulate and/or tolerate heavy metals, the
American Society of Plant Physiologists.
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19. Increased Activity of [gamma]-Glutamylcysteine Synthetase in Tomato Cells Selected for Cadmium Tolerance.
Two cell lines of tomato (Lycopersicon esculentum Mill cv VFNT-Cherry) were systematically compared for their capacity to tolerate cadmium. Unselected CdS cells died in the presence of 0.3 mM CdCl2. CdR6-0 cells, which were selected from CdS, survived and grew in medium supplemented with 0.3 mM CdCl2. Growth of CdR6-0 cells under this condition was accompani
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20. Retention of cadmium in roots of maize seedlings. Role of complexation by phytochelatins and related thiol peptides.
Cd from roots of maize was partitioned in seedlings exposed to 3 microM CdSO4 for 1 to 7 d. Most of the root Cd (92-94%) was buffer soluble and provided the classical metal-induced cysteine-rich, high-molecular-weight Cd-binding complex. This complex, however, bound only part of the Cd within the roots, from 19% after 1 d of exposure to 59% by d 7. Three fam
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21. Functional homologs of fungal metallothionein genes from Arabidopsis.
Metallothioneins (MTs) are cysteine-rich proteins required for heavy metal tolerance in animals and fungi. Two cDNAs encoding proteins with homology to animal and fungal MTs have been isolated from Arabidopsis. The genes represented by these cDNAs are referred to as MT1 and MT2. When expressed in an MT-deficient (cup1 delta) mutant of yeast, both MT1 and MT2
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22. Cadmium-sensitive, cad1 mutants of Arabidopsis thaliana are phytochelatin deficient.
An allelic series of cad1, cadmium-sensitive mutants of Arabidopsis thaliana, was isolated. These mutants were sensitive to cadmium to different extents and were deficient in their ability to form cadmium-peptide complexes as detected by gel-filtration chromatography. Each mutant was deficient in its ability to accumulate phytochelatins (PCs) as detected by
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23. Long-distance root-to-shoot transport of phytochelatins and cadmium in Arabidopsis
Phytochelatin synthases (PCS) mediate cellular heavy-metal resistance in plants, fungi, and worms. However, phytochelatins (PCs) are generally considered to function as intracellular heavy-metal detoxification mechanisms, and whether long-distance transport of PCs occurs during heavy-metal detoxification remains unknown. Here, wheat TaPCS1 cDNA expressio
National Academy of Sciences.
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24. Phytochelatins in Cadmium-Sensitive and Cadmium-Tolerant Silene vulgaris (Chain Length Distribution and Sulfide Incorporation).
In response to a range of Cd concentrations, the root tips of Cd-tolerant plants of Silene vulgaris exhibit a lower rate of PC production accompanied by a lower rate of longer chain PC synthesis than those of Cd-sensitive plants. At the same Cd exposure level, stable PC-Cd complexes are more rapidly formed in the roots of Cd-sensitive plants than in those of