Plasma membrane ferric reductase activity of iron-limited algal cells is inhibited by ferric chelators

BioMetals ◽  
2010 ◽  
Vol 23 (6) ◽  
pp. 1029-1042 ◽  
Author(s):  
Mathew B. Sonier ◽  
Harold G. Weger
Keyword(s):  
Plasma Membrane ◽  
Reductase Activity ◽  
Ferric Reductase

scholarly journals Azo Reductase Activity of Intact Saccharomyces cerevisiae Cells Is Dependent on the Fre1p Component of Plasma Membrane Ferric Reductase

2005 ◽  
Vol 71 (7) ◽  
pp. 3882-3888 ◽  
Author(s):  
Patrícia A. Ramalho ◽  
Sandra Paiva ◽  
A. Cavaco-Paulo ◽  
Margarida Casal ◽  
M. Helena Cardoso ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Azo Dyes ◽  
Reductase Activity ◽  
Redox System ◽  
Ferric Reductase ◽  
Bacterial Reduction ◽  
Azo Reductase ◽  
In The Wild ◽  
Ascomycete Yeast

ABSTRACT Unspecific bacterial reduction of azo dyes is a process widely studied in correlation with the biological treatment of colored wastewaters, but the enzyme system associated with this bacterial capability has never been positively identified. Several ascomycete yeast strains display similar decolorizing behaviors. The yeast-mediated process requires an alternative carbon and energy source and is independent of previous exposure to the dyes. When substrate dyes are polar, their reduction is extracellular, strongly suggesting the involvement of an externally directed plasma membrane redox system. The present work demonstrates that, in Saccharomyces cerevisiae, the ferric reductase system participates in the extracellular reduction of azo dyes. The S. cerevisiae Δfre1 and Δfre1 Δfre2 mutant strains, but not the Δfre2 strain, showed much-reduced decolorizing capabilities. The FRE1 gene complemented the phenotype of S. cerevisiae Δfre1 cells, restoring the ability to grow in medium without externally added iron and to decolorize the dye, following a pattern similar to the one observed in the wild-type strain. These results suggest that under the conditions tested, Fre1p is a major component of the azo reductase activity.

scholarly journals Genetic evidence that ferric reductase is required for iron uptake in Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (5) ◽  
pp. 2294-2301 ◽  
Author(s):  
A Dancis ◽  
R D Klausner ◽  
A G Hinnebusch ◽  
J G Barriocanal
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Iron Uptake ◽  
Reductase Activity ◽  
Gene Transcript ◽  
Single Mutation ◽  
Uptake System ◽  
Ferric Reductase ◽  
Wild Type ◽  
Iron Starvation

The requirement for a reduction step in cellular iron uptake has been postulated, and the existence of plasma membrane ferric reductase activity has been described in both procaryotic and eucaryotic cells. In the yeast Saccharomyces cerevisiae, there is an externally directed reductase activity that is regulated by the concentration of iron in the growth medium; maximal activity is induced by iron starvation. We report here the isolation of a mutant of S. cerevisiae lacking the reductase activity. This mutant is deficient in the uptake of ferric iron and is extremely sensitive to iron deprivation. Genetic analysis of the mutant demonstrates that the reductase and ferric uptake deficiencies are due to a single mutation that we designate fre1-1. Both phenotypes cosegregate in meiosis, corevert with a frequency of 10(-7), and are complemented by a 3.5-kilobase fragment of genomic DNA from wild-type S. cerevisiae. This fragment contains FRE1, the wild-type allele of the mutant gene. The level of the gene transcript is regulated by iron in the same was as the reductase activity. The ferrous ion product of the reductase must traverse the plasma membrane. A high-affinity (Km = 5 microM) ferrous uptake system is present in both wild-type and mutant cells. Thus, iron uptake in S. cerevisiae is mediated by two plasma membrane components, a reductase and a ferrous transport system.

scholarly journals Growth and physiological impairments in Fe-starved alfalfa are associated with the downregulation of Fe and S transporters along with redox imbalance

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Md Atikur Rahman ◽  
Md Bulbul Ahmed ◽  
Fahad Alotaibi ◽  
Khaled D. Alotaibi ◽  
Noura Ziadi ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Crop Production ◽  
Production Systems ◽  
Plant Biomass ◽  
Reductase Activity ◽  
In Silico Analysis ◽  
Fe Deficiency ◽  
Ferric Reductase ◽  
Plasma Membrane Atpase ◽  
Oxidative Damages

Abstract Background Iron (Fe) is an essential plant nutrient. Its deficiency is a major constraint in crop production systems, affecting crop yield and quality. It is therefore important to elucidate the responses and adaptive mechanisms underlying Fe-deficiency symptoms in alfalfa. Materials and methods The experiment was carried out on 12-day-old alfalfa plants grown in hydroponics under Fe-sufficient and Fe-deficient conditions. Results The Fe-starved alfalfa showed decreased plant biomass, chlorophyll score, PSII efficiency, and photosynthesis performance index in young leaves under low Fe. Further, Fe shortage reduced the Fe, Zn, S and Ca concentration in root and shoot of alfalfa accompanied by the marked decrease of MsIRT1, MsZIP, MsSULTR1;1, MsSULTR1;2 and MsSULTR1;3 transcripts in root and shoot. It indicates that retardation caused by Fe-deficiency was also associated with the status of other elements, especially the reduced Fe and S may be coordinately attributed to the photosynthetic damages in Fe-deficient alfalfa. The ferric chelate reductase activity accompanied by the expression of MsFRO1 in roots showed no substantial changes, indicating the possible involvement of this Strategy I response in Fe-deficient alfalfa. However, the proton extrusion and expression of MsHAI1 were significantly induced following Fe-deficiency. In silico analysis further suggested their subcellular localization in the plasma membrane. Also, the interactome map suggested the partnership of MsFRO1 with plasma membrane H+-ATPase, transcription factor bHLH47, and nitrate reductase genes, while MsHAI1 partners include ferric reductase-like transmembrane component, plasma membrane ATPase, vacuolar-type H-pyrophosphatase, and general regulatory factor 2. In this study, SOD and APX enzymes showed a substantial increase in roots but unable to restore the oxidative damages in Fe-starved alfalfa. Conclusion These findings promote further studies for the improvement of Fe-starved alfalfa or legumes through breeding or transgenic approaches. Graphic Abstract

Genetic evidence that ferric reductase is required for iron uptake in Saccharomyces cerevisiae

1990 ◽  
Vol 10 (5) ◽  
pp. 2294-2301
Author(s):  
A Dancis ◽  
R D Klausner ◽  
A G Hinnebusch ◽  
J G Barriocanal
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Iron Uptake ◽  
Reductase Activity ◽  
Gene Transcript ◽  
Single Mutation ◽  
Uptake System ◽  
Ferric Reductase ◽  
Wild Type ◽  
Iron Starvation

The requirement for a reduction step in cellular iron uptake has been postulated, and the existence of plasma membrane ferric reductase activity has been described in both procaryotic and eucaryotic cells. In the yeast Saccharomyces cerevisiae, there is an externally directed reductase activity that is regulated by the concentration of iron in the growth medium; maximal activity is induced by iron starvation. We report here the isolation of a mutant of S. cerevisiae lacking the reductase activity. This mutant is deficient in the uptake of ferric iron and is extremely sensitive to iron deprivation. Genetic analysis of the mutant demonstrates that the reductase and ferric uptake deficiencies are due to a single mutation that we designate fre1-1. Both phenotypes cosegregate in meiosis, corevert with a frequency of 10(-7), and are complemented by a 3.5-kilobase fragment of genomic DNA from wild-type S. cerevisiae. This fragment contains FRE1, the wild-type allele of the mutant gene. The level of the gene transcript is regulated by iron in the same was as the reductase activity. The ferrous ion product of the reductase must traverse the plasma membrane. A high-affinity (Km = 5 microM) ferrous uptake system is present in both wild-type and mutant cells. Thus, iron uptake in S. cerevisiae is mediated by two plasma membrane components, a reductase and a ferrous transport system.

scholarly journals The fission yeast ferric reductase gene frp1+ is required for ferric iron uptake and encodes a protein that is homologous to the gp91-phox subunit of the human NADPH phagocyte oxidoreductase

1993 ◽  
Vol 13 (7) ◽  
pp. 4342-4350
Author(s):  
D G Roman ◽  
A Dancis ◽  
G J Anderson ◽  
R D Klausner
Keyword(s):  
Fission Yeast ◽  
Iron Uptake ◽  
Ferric Iron ◽  
Reductase Activity ◽  
Iron Acquisition ◽  
Protein A ◽  
Mutant Gene ◽  
Predicted Amino Acid Sequence ◽  
Mrna Levels ◽  
Ferric Reductase

We have identified a cell surface ferric reductase activity in the fission yeast Schizosaccharomyces pombe. A mutant strain deficient in this activity was also deficient in ferric iron uptake, while ferrous iron uptake was not impaired. Therefore, reduction is a required step in cellular ferric iron acquisition. We have cloned frp1+, the wild-type allele of the mutant gene. frp1+ mRNA levels were repressed by iron addition to the growth medium. Fusion of 138 nucleotides of frp1+ promoter sequences to a reporter gene, the bacterial chloramphenicol acetyltransferase gene, conferred iron-dependent regulation upon the latter when introduced into S. pombe. The predicted amino acid sequence of the frp1+ gene exhibits hydrophobic regions compatible with transmembrane domains. It shows similarity to the Saccharomyces cerevisiae FRE1 gene product and the gp91-phox protein, a component of the human NADPH phagocyte oxidoreductase that is deficient in X-linked chronic granulomatous disease.

Two Phases Of Ferricyanide Reductase Activity In Ehrlich Cell Plasma Membranes

1992 ◽  
Vol 47 (11-12) ◽  
pp. 929-931 ◽  
Author(s):  
Antonio del Castillo-Olivares ◽  
Javier Márquez ◽  
Ignacio Núñez de Castro ◽  
Miguel Angel Medina
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Reductase Activity ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Cell Plasma Membrane ◽  
Ferricyanide Reductase ◽  
Ehrlich Cell ◽  
Cell Plasma ◽  
Two Phases

Ehrlich cell plasma membrane vesicles have a ferricyanide reductase activity that shows two phases. These two phases were kinetically characterized. Evidence is presented for a differential effect of trypsin on both phases

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