scholarly journals Free flavins accelerate release of ferrous iron from iron storage proteins by both free flavin-dependent and -independent ferric reductases in Escherichia coli

2019 ◽  
Vol 65 (6) ◽  
pp. 308-315
Author(s):  
Junichi Satoh ◽  
Shinya Kimata ◽  
Shota Nakamoto ◽  
Tatsuya Ishii ◽  
Eisuke Tanaka ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ferrous Iron ◽  
Storage Proteins ◽  
Iron Storage ◽  
Iron Storage Proteins ◽  
Ferric Reductases

scholarly journals Ferritin Mutants of Escherichia coli Are Iron Deficient and Growth Impaired, and fur Mutants are Iron Deficient

1999 ◽  
Vol 181 (5) ◽  
pp. 1415-1428 ◽  
Author(s):  
Hossein Abdul-Tehrani ◽  
Aaron J. Hudson ◽  
Yung-Sheng Chang ◽  
Andrew R. Timms ◽  
Chris Hawkins ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ferric Iron ◽  
Storage Proteins ◽  
Iron Acquisition ◽  
Constitutive Expression ◽  
Iron Store ◽  
Iron Storage ◽  
Rich Media ◽  
Iron Deficient ◽  
Iron Storage Proteins

ABSTRACT Escherichia coli contains at least two iron storage proteins, a ferritin (FtnA) and a bacterioferritin (Bfr). To investigate their specific functions, the corresponding genes (ftnA and bfr) were inactivated by replacing the chromosomal ftnA and bfr genes with disrupted derivatives containing antibiotic resistance cassettes in place of internal segments of the corresponding coding regions. Single mutants (ftnA::spc andbfr::kan) and a double mutant (ftnA::spc bfr::kan) were generated and confirmed by Western and Southern blot analyses. The iron contents of the parental strain (W3110) and the bfr mutant increased by 1.5- to 2-fold during the transition from logarithmic to stationary phase in iron-rich media, whereas the iron contents of theftnA and ftnA bfr mutants remained unchanged. The ftnA and ftnA bfr mutants were growth impaired in iron-deficient media, but this was apparent only after the mutant and parental strains had been precultured in iron-rich media. Surprisingly, ferric iron uptake regulation (fur) mutants also had very low iron contents (2.5-fold less iron than Fur+ strains) despite constitutive expression of the iron acquisition systems. The iron deficiencies of the ftnA andfur mutants were confirmed by Mössbauer spectroscopy, which further showed that the low iron contents of ftnAmutants are due to a lack of magnetically ordered ferric iron clusters likely to correspond to FtnA iron cores. In combination with thefur mutation, ftnA and bfrmutations produced an enhanced sensitivity to hydroperoxides, presumably due to an increase in production of “reactive ferrous iron.” It is concluded that FtnA acts as an iron store accommodating up to 50% of the cellular iron during postexponential growth in iron-rich media and providing a source of iron that partially compensates for iron deficiency during iron-restricted growth. In addition to repressing the iron acquisition systems, Fur appears to regulate the demand for iron, probably by controlling the expression of iron-containing proteins. The role of Bfr remains unclear.

scholarly journals Distinct Effects of Escherichia coli,Pseudomonas aeruginosa and Staphylococcus aureus Cell Wall Component-Induced Inflammation on the Iron Metabolism of THP-1 Cells

2021 ◽  
Vol 22 (3) ◽  
pp. 1497
Author(s):  
Edina Pandur ◽  
Kitti Tamási ◽  
Ramóna Pap ◽  
Gergely Jánosa ◽  
Katalin Sipos
Keyword(s):  
Cell Wall ◽  
Inflammatory Cytokines ◽  
Iron Metabolism ◽  
Inflammatory Cytokine ◽  
Cytokine Production ◽  
Storage Proteins ◽  
Iron Storage ◽  
E Coli ◽  
Iron Storage Proteins ◽  
Pro Inflammatory Cytokines

Macrophages are essential immune cells of the innate immune system. They participate in the development and regulation of inflammation. Macrophages play a fundamental role in fighting against bacterial infections by phagocytosis of bacteria, and they also have a specific role in immunomodulation by secreting pro-inflammatory cytokines. In bacterial infection, macrophages decrease the serum iron concentration by removing iron from the blood, acting as one of the most important regulatory cells of iron homeostasis. We examined whether the Gram-positive and Gram-negative cell wall components from various bacterial strains affect the cytokine production and iron transport, storage and utilization of THP-1 monocytes in different ways. We found that S. aureus lipoteichoic acid (LTA) was less effective in activating pro-inflammatory cytokine expression that may related to its effect on fractalkine production. LTA-treated cells increased iron uptake through divalent metal transporter-1, but did not elevate the expression of cytosolic and mitochondrial iron storage proteins, suggesting that the cells maintained iron efflux via the ferroportin iron exporter. E. coli and P. aeruginosa lipopolysaccharides (LPSs) acted similarly on THP-1 cells, but the rates of the alterations of the examined proteins were different. E. coli LPS was more effective in increasing the pro-inflammatory cytokine production, meanwhile it caused less dramatic alterations in iron metabolism. P. aeruginosa LPS-treated cells produced a smaller amount of pro-inflammatory cytokines, but caused remarkable elevation of both cytosolic and mitochondrial iron storage proteins and intracellular iron content compared to E. coli LPS. These results prove that LPS molecules from different bacterial sources alter diverse molecular mechanisms in macrophages that prepossess the outcome of the bacterial infection.

The importance of eukaryotic ferritins in iron handling and cytoprotection

2015 ◽  
Vol 472 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Paolo Arosio ◽  
Fernando Carmona ◽  
Raffaella Gozzelino ◽  
Federica Maccarinelli ◽  
Maura Poli
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Animal Models ◽  
Storage Proteins ◽  
Eukaryotic Cells ◽  
Intracellular Iron ◽  
Iron Storage ◽  
Iron Incorporation ◽  
Iron Storage Proteins ◽  
Response Activation

Ferritins, the main intracellular iron storage proteins, have been studied for over 60 years, mainly focusing on the mammalian ones. This allowed the elucidation of the structure of these proteins and the mechanisms regulating their iron incorporation and mineralization. However, ferritin is present in most, although not all, eukaryotic cells, comprising monocellular and multicellular invertebrates and vertebrates. The aim of this review is to provide an update on the general properties of ferritins that are common to various eukaryotic phyla (except plants), and to give an overview on the structure, function and regulation of ferritins. An update on the animal models that were used to characterize H, L and mitochondrial ferritins is also provided. The data show that ferritin structure is highly conserved among different phyla. It exerts an important cytoprotective function against oxidative damage and plays a role in innate immunity, where it also contributes to prevent parenchymal tissue from the cytotoxicity of pro-inflammatory agonists released by the activation of the immune response activation. Less clear are the properties of the secretory ferritins expressed by insects and molluscs, which may be important for understanding the role played by serum ferritin in mammals.

scholarly journals PerR Controls Oxidative Stress Resistance and Iron Storage Proteins and Is Required for Virulence in Staphylococcus aureus

2001 ◽  
Vol 69 (6) ◽  
pp. 3744-3754 ◽  
Author(s):  
Malcolm J. Horsburgh ◽  
Mark O. Clements ◽  
Howard Crossley ◽  
Eileen Ingham ◽  
Simon J. Foster
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Stress Resistance ◽  
Iron Homeostasis ◽  
Storage Proteins ◽  
Iron Storage ◽  
Oxidative Stress Resistance ◽  
Genes Encoding ◽  
Starvation Survival ◽  
Iron Storage Proteins

ABSTRACT The Staphylococcus aureus genome encodes three ferric uptake regulator (Fur) homologues: Fur, PerR, and Zur. To determine the exact role of PerR, we inactivated the gene by allelic replacement using a kanamycin cassette, creating strain MJH001 (perR). PerR was found to control transcription of the genes encoding the oxidative stress resistance proteins catalase (KatA), alkyl hydroperoxide reductase (AhpCF), bacterioferritin comigratory protein (Bcp), and thioredoxin reductase (TrxB). Furthermore, PerR regulates transcription of the genes encoding the iron storage proteins ferritin (Ftn) and the ferritin-like Dps homologue, MrgA. Transcription of perR was autoregulated, and PerR repressed transcription of the iron homeostasis regulator Fur, which is a positive regulator of catalase expression. PerR functions as a manganese-dependent, transcriptional repressor of the identified regulon. Elevated iron concentrations produced induction of the PerR regulon. PerR may act as a peroxide sensor, since addition of external hydrogen peroxide to 8325-4 (wild type) resulted in increased transcription of most of the PerR regulon, except forfur and perR itself. The PerR-regulatedkatA gene encodes the sole catalase of S. aureus, which is an important starvation survival determinant but is surprisingly not required for pathogenicity in a murine skin abscess model of infection. In contrast, PerR is not necessary for starvation survival but is required for full virulence (P < 0.005) in this model of infection. PerR ofS. aureus may act as a redox sentinel protein during infection, analogous to the in vitro activities of OxyR and PerR ofEscherichia coli and Bacillus subtilis, respectively. However, it differs in its response to the metal balance within the cell and has the added capability of regulating iron uptake and storage.

On the magnetic ordering of the iron storage proteins in tissues

2004 ◽  
Vol 272-276 ◽  
pp. 2422-2423 ◽  
Author(s):  
Olga Mykhaylyk ◽  
Gyula Török ◽  
Olexandr Dudchenko ◽  
Oksana Stavinska ◽  
Nataly Dudchenko ◽  
...  
Keyword(s):  
Storage Proteins ◽  
Magnetic Ordering ◽  
Iron Storage ◽  
Iron Storage Proteins
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