Copper and zinc differentially affect root glutathione accumulation and phytochelatin synthase gene expression of Rhizophora mucronata seedlings: Implications for mechanisms underlying trace metal tolerance

Phytochelatins (PCs) are heavy metal binding peptides that play important roles in sequestration and detoxification of heavy metals in plants. To develop transgenic plants with increased tolerance and/or accumulation of heavy metals from soil, an Arabidopsis thaliana FLAG–tagged AtPCS1 cDNA encoding phytochelatin synthase (PCS) under the control of a 35S promoter was expressed in Indian mustard (Brassica juncea). Four transgenic Indian mustard lines, designated pc lines, with different levels of AtPCS1 mRNA accumulation and correspondent AtPCS1 protein levels were selected and analyzed for tolerance to cadmium (Cd) and zinc (Zn). Heavy metal tolerance was assessed by measuring root length of 10-day-old seedlings grown on agar medium supplemented with different concentrations of Cd (0, 100, 150, and 200 μm CdCl2) and Zn (200, 400, 600, and 800 μm ZnCl2). All transgenic lines showed significantly longer roots when grown on a medium supplemented with 100 μm CdCl2. No significant differences were observed between transgenic lines and wild type when plants were grown on higher levels of Cd. This indicated that only partial tolerance to Cd was observed in these transgenic lines. Similarly, partial tolerance for Zn was also observed in these transgenic lines, but up to levels of 400 μm ZnCl2. Expression levels of AtPCS1 protein were not related to tolerance responses for either Cd or Zn stresses in transgenic lines.

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The effect of stage of growth on the copper, zinc, manganese, and molybdenum contents of Algerian oats grown of thirteen soils

Australian Journal of Agricultural Research ◽

10.1071/ar9520343 ◽

1952 ◽

Vol 3 (4) ◽

pp. 343 ◽

Cited By ~ 25

Author(s):

CH Williams ◽

CWE Moore

Keyword(s):

Trace Metal ◽

Soil Ph ◽

Dry Matter ◽

Growing Period ◽

Stages Of Growth ◽

Early Stages ◽

Copper And Zinc ◽

Rate Of Increase ◽

Metal Contents ◽

Copper Zinc

Algerian oats were grown on 13 soils in the glass-house. Plants were harvested at intervals throughout the growing period, and when large enough were divided into leaf, stem, and (in later harvests) flowers or fruits. Copper, zinc, manganese, and molybdenum were determined on the separate plant fractions. Characteristic changes in the trace metal contents of the plant with growth were found for each element. These changes were generally similar irrespective of the soil on which the plants were grown. With the exception of manganese, the availability of the element in the soil did not affect the trend of the changes as the plant matured, but only the amount present. The uptake of each of the four elements continued through the whole period of growth. The total amounts of copper and zinc in both the leaf and the stem decreased after flowering as translocation to the grain proceeded. The amount of manganese in the leaf increased throughout the period of growth, although the rate of increase was less after flowering. The amount of molybdenum in the leaf increased until flowering, after which there was little further change. The rate of uptake of manganese was approximately equal to the rate of production of dry matter, whereas that of molybdenum, copper, and zinc was relatively greater in the early stages of growth. There was no observable influence of soil pH on the availability of copper and zinc, but that of manganese decreased with increasing pH. The availability of molybdenum was affected by the combined influences of soil pH and soil iron.

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On the selection for heavy metal tolerance in diatoms from the Derwent estuary, Tasmania

Marine and Freshwater Research ◽

10.1071/mf9810555 ◽

1981 ◽

Vol 32 (4) ◽

pp. 555 ◽

Cited By ~ 13

Author(s):

NS Fisher

Keyword(s):

Metal Uptake ◽

Growth Response ◽

Metal Tolerance ◽

Skeletonema Costatum ◽

Heavy Metal Tolerance ◽

Copper Tolerance ◽

Lag Phase ◽

Copper And Zinc ◽

Clonal Cultures ◽

Selection For

To assess the metal tolerance of phytoplankton from the polluted Derwent estuary in Tasmania, unialgal clonal cultures of three marine diatoms were established from recent isolates. Skeletonema costatum, Melosira moniliformis, and Gyrosigma sp, were exposed to varying levels of copper and zinc and metal uptake and growth response were monitored. Cells of S. costatum, the only species for which direct comparisons were possible, appeared to have greater zinc, but not copper, tolerance than had S. costatum cells isolated from cleaner waters. Unlike the other species, Gyrosigma sp. responded to zinc stress with an extended lag phase, followed by apparent recovery. Uptake of copper and zinc by these species did not significantly differ from that of more sensitive cells. In the Derwent water from which the cells were isolated, the total dissolved copper concentration was 1763 nM, with only 69 nM being polarographically labile, while 84% of the total dissolved zinc (concn 1805 nM) was labile. It appears that it is the labile metal, rather than total metal, which provides selection pressure for metal tolerance, presumably because only this fraction is available for algal uptake.

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Metallothionein Gene Expression in Rats: Tissue-Specific Regulation by Dietary Copper and Zinc

Journal of Nutrition ◽

10.1093/jn/118.2.222 ◽

1988 ◽

Vol 118 (2) ◽

pp. 222-228 ◽

Cited By ~ 85

Author(s):

T. Lynn Blalock ◽

Michael A. Dunn ◽

Robert J. Cousins

Keyword(s):

Gene Expression ◽

Dietary Copper ◽

Tissue Specific ◽

Metallothionein Gene ◽

Copper And Zinc ◽

Specific Regulation

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IMPROVING HEAVY METAL TOLERANCE OF YEAST BY TRANSFERRING A PHYTOCHELATIN SYNTHASE GENE FROM GARLIC

Chinese Journal of Plant Ecology ◽

10.17521/cjpe.2005.0088 ◽

2005 ◽

Vol 29 (4) ◽

pp. 659-664

Author(s):

JIANG Ying-Nan ◽

◽

FENG Bao-Min ◽

ZHANG Hai-Yan ◽

MA Mi

Keyword(s):

Heavy Metal ◽

Metal Tolerance ◽

Heavy Metal Tolerance ◽

Phytochelatin Synthase

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Imbalances in Copper or Zinc Concentrations Trigger Further Trace Metal Dyshomeostasis in Amyloid-Beta Producing Caenorhabditis elegans

Frontiers in Neuroscience ◽

10.3389/fnins.2021.755475 ◽

2021 ◽

Vol 15 ◽

Author(s):

Ada Metaxas

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Trace Metals ◽

Trace Metal ◽

Amyloid Beta ◽

Model Organism ◽

Return To Equilibrium ◽

C Elegans ◽

Copper And Zinc ◽

The Impact

Alzheimer's Disease (AD), a progressive neurodegenerative disease characterized by the buildup of amyloid-beta (Aβ) plaques, is believed to be a disease of trace metal dyshomeostasis. Amyloid-beta is known to bind with high affinity to trace metals copper and zinc. This binding is believed to cause a conformational change in Aβ, transforming Aβ into a configuration more amenable to forming aggregations. Currently, the impact of Aβ-trace metal binding on trace metal homeostasis and the role of trace metals copper and zinc as deleterious or beneficial in AD remain elusive. Given that Alzheimer's Disease is the sixth leading cause of adult death in the U.S., elucidating the molecular interactions that characterize Alzheimer's Disease pathogenesis will allow for better treatment options. To that end, the model organism C. elegans is used in this study. C. elegans, a transparent nematode whose connectome has been fully established, is an amenable model to study AD phenomena using a multi-layered, interconnected approach. Aβ-producing and non-Aβ-producing C. elegans were individually supplemented with copper and zinc. On day 6 and day 9 after synchronization, the percent of worms paralyzed, concentration of copper, and concentration of zinc were measured in both groups of worms. This study demonstrates that dyshomeostasis of trace metals copper or zinc triggers further trace metal dyshomeostasis in Aβ-producing worms, while dyshomeostasis of copper or zinc triggers a return to equilibrium in non-Aβ-producing worms. This supports the characterization of Alzheimer's Disease as a disease of trace metal dyshomeostasis.

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