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Michael E. P. Murphy - One of the best experts on this subject based on the ideXlab platform.
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The B-type Channel Is a Major Route for Iron Entry into the Ferroxidase Center and Central Cavity of Bacterioferritin
Journal of Biological Chemistry, 2014Co-Authors: Steve G. Wong, Jason C. Grigg, Nick E. Le Brun, Michael E. P. Murphy, A. Grant MaukAbstract:Bacterioferritin is a bacterial Iron Storage and detoxification protein that is capable of forming a ferric oxyhydroxide mineral core within its central cavity. To do this, Iron must traverse the bacterioferritin protein shell, which is expected to occur through one or more of the channels through the shell identified by structural studies. The size and negative electrostatic potential of the 24 B-type channels suggest that they could provide a route for Iron into bacterioferritin. Residues at the B-type channel (Asn-34, Glu-66, Asp-132, and Asp-139) of E. coli bacterioferritin were substituted to determine if they are important for Iron core formation. A significant decrease in the rates of initial oxidation of Fe(II) at the ferroxidase center and subsequent Iron mineralization was observed for the D132F variant. The crystal structure of this variant shows that substitution of residue 132 with phenylalanine caused a steric blockage of the B-type channel and no other material structural perturbation. We conclude that the B-type channel is a major route for Iron entry into both the ferroxidase center and the Iron Storage cavity of bacterioferritin.
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ferritin is used for Iron Storage in bloom forming marine pennate diatoms
Nature, 2009Co-Authors: Adrian Marchetti, Michael E. P. Murphy, Micaela S Parker, Lauren P Moccia, Angele L Arrieta, Francois Ribalet, Maria T Maldonado, Virginia E ArmbrustAbstract:The non-haem protein ferritin is used by many plants, animals and microorganisms to store Iron in a non-toxic soluble form that can be readily mobilized when required. Ferritin has now been found in the two diatoms, Pseudo-nitzschia and Fragilariopsis, that dominate phytoplankton blooms induced by both natural and artificial oceanic Iron supplementation. This is the first report of ferritin in any member of the Stramenopila, the eukaryote lineage that includes many plankton components including unicellular algae, diatoms and macroalgae. Phylogenetic analysis suggests that ferritin arose in this small subset of diatoms via lateral gene transfer, and it may be key to their success in the 30–40% of ocean waters in which Iron availability is the factor limiting primary productivity. Natural or artificial oceanic Iron supplementation induces blooms that are dominated by pennate diatoms. It is shown that these diatoms contain the Iron Storage protein ferritin, which may explain their success in Iron-limited waters. Primary productivity in 30–40% of the world’s oceans is limited by availability of the micronutrient Iron1,2. Regions with chronically low Iron concentrations are sporadically pulsed with new Iron inputs by way of dust3 or lateral advection from continental margins4. Addition of Iron to surface waters in these areas induces massive phytoplankton blooms dominated primarily by pennate diatoms5,6. Here we provide evidence that the bloom-forming pennate diatoms Pseudo-nitzschia and Fragilariopsis use the Iron-concentrating protein, ferritin, to safely store Iron. Ferritin has not been reported previously in any member of the Stramenopiles, a diverse eukaryotic lineage that includes unicellular algae, macroalgae and plant parasites. Phylogenetic analyses suggest that ferritin may have arisen in this small subset of diatoms through a lateral gene transfer. The crystal structure and functional assays of recombinant ferritin derived from Pseudo-nitzschia multiseries reveal a maxi-ferritin that exhibits ferroxidase activity and binds Iron. The protein is predicted to be targeted to the chloroplast to control the distribution and Storage of Iron for proper functioning of the photosynthetic machinery. Abundance of Pseudo-nitzschia ferritin transcripts is regulated by Iron nutritional status, and is closely tied to the loss and recovery of photosynthetic competence. Enhanced Iron Storage with ferritin allows the oceanic diatom Pseudo-nitzschia granii to undergo several more cell divisions in the absence of Iron than the comparably sized, oceanic centric diatom Thalassiosira oceanica. Ferritin in pennate diatoms probably contributes to their success in chronically low-Iron regions that receive intermittent Iron inputs, and provides an explanation for the importance of these organisms in regulating oceanic CO2 over geological timescales7,8.
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Ferritin is used for Iron Storage in bloom-forming marine pennate diatoms
Nature, 2008Co-Authors: Adrian Marchetti, Michael E. P. Murphy, Micaela S Parker, Lauren P Moccia, Angele L Arrieta, Francois Ribalet, Maria T Maldonado, Ellen O. Lin, E. Virginia ArmbrustAbstract:The non-haem protein ferritin is used by many plants, animals and microorganisms to store Iron in a non-toxic soluble form that can be readily mobilized when required. Ferritin has now been found in the two diatoms, Pseudo-nitzschia and Fragilariopsis, that dominate phytoplankton blooms induced by both natural and artificial oceanic Iron supplementation. This is the first report of ferritin in any member of the Stramenopila, the eukaryote lineage that includes many plankton components including unicellular algae, diatoms and macroalgae. Phylogenetic analysis suggests that ferritin arose in this small subset of diatoms via lateral gene transfer, and it may be key to their success in the 30–40% of ocean waters in which Iron availability is the factor limiting primary productivity. Natural or artificial oceanic Iron supplementation induces blooms that are dominated by pennate diatoms. It is shown that these diatoms contain the Iron Storage protein ferritin, which may explain their success in Iron-limited waters. Primary productivity in 30–40% of the world’s oceans is limited by availability of the micronutrient Iron1,2. Regions with chronically low Iron concentrations are sporadically pulsed with new Iron inputs by way of dust3 or lateral advection from continental margins4. Addition of Iron to surface waters in these areas induces massive phytoplankton blooms dominated primarily by pennate diatoms5,6. Here we provide evidence that the bloom-forming pennate diatoms Pseudo-nitzschia and Fragilariopsis use the Iron-concentrating protein, ferritin, to safely store Iron. Ferritin has not been reported previously in any member of the Stramenopiles, a diverse eukaryotic lineage that includes unicellular algae, macroalgae and plant parasites. Phylogenetic analyses suggest that ferritin may have arisen in this small subset of diatoms through a lateral gene transfer. The crystal structure and functional assays of recombinant ferritin derived from Pseudo-nitzschia multiseries reveal a maxi-ferritin that exhibits ferroxidase activity and binds Iron. The protein is predicted to be targeted to the chloroplast to control the distribution and Storage of Iron for proper functioning of the photosynthetic machinery. Abundance of Pseudo-nitzschia ferritin transcripts is regulated by Iron nutritional status, and is closely tied to the loss and recovery of photosynthetic competence. Enhanced Iron Storage with ferritin allows the oceanic diatom Pseudo-nitzschia granii to undergo several more cell divisions in the absence of Iron than the comparably sized, oceanic centric diatom Thalassiosira oceanica. Ferritin in pennate diatoms probably contributes to their success in chronically low-Iron regions that receive intermittent Iron inputs, and provides an explanation for the importance of these organisms in regulating oceanic CO2 over geological timescales7,8.
Laila Jarjour - One of the best experts on this subject based on the ideXlab platform.
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Low Iron Storage in children and adolescents with neurally mediated syncope.
The Journal of pediatrics, 2008Co-Authors: Imad Jarjour, Laila JarjourAbstract:Objective To investigate whether neurally mediated syncope (NMS) is associated with low Iron Storage or serum ferritin (SF). Study design 206 children evaluated between 2000 and 2004 for probable syncope at a tertiary care Pediatric Neurology Clinic were included in a retrospective study. Serum ferritin (SF), Iron, total Iron binding capacity, and hemoglobin were measured prospectively after initial history taking and physical examination, along with other diagnostic testing. We defined Iron deficiency (ID) as SF Results Among 106 included patients with syncope, 71 had NMS and 35 had other causes of syncope. Patients with NMS, when compared with those with other causes of syncope, had a higher prevalence of low Iron Storage (57% vs 17%, P P P , P Conclusions Low Iron Storage or serum ferritin is associated with NMS and is a potentially pathophysiologic factor in NMS.
Flemming Brandrup - One of the best experts on this subject based on the ideXlab platform.
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familial and sporadic porphyria cutanea tarda clinical biochemical and genetic features with emphasis on Iron status
Acta Dermato-venereologica, 2003Co-Authors: Anette Bygum, M Horder, Niels Erik Petersen, Lene Christiansen, Kristian Thomsen, Flemming BrandrupAbstract:The manifestation of porphyria cutanea tarda reflects genetic and envIronmental factors. Mutations in the uroporphyrinogen decarboxylase gene, located at chromosome 1p34, discriminate familial porphyria cutanea tarda from sporadic cases. Furthermore, mutations in the haemochromatosis gene may be involved in the aetiology. In this study 53 unrelated Danish patients with porphyria cutanea tarda were classified according to uroporphyrinogen decarboxylase and haemochromatosis gene mutations and the genotype related to the clinical and biochemical data. Thirteen patients (25%) had familial porphyria cutanea tarda. The results signify the advantage of DNA diagnostics for identification of familial cases, as anamnestic data are doubtful and erythrocyte uroporphyrinogen decarboxylase activity measurements insufficient for correct classification. Eight patients with porphyria cutanea tarda (15%) were homozygous for the haemochromatosis gene C282Y mutation and 8 patients were heterozygous. Patients homozygous for the haemochromatosis related mutation showed biochemical evidence of excessive Iron Storage as well as increased urine porphyrin excretion levels. This seems to confirm a relationship between porphyria cutanea tarda and haemochromatosis. No differences were found between patients with sporadic and familial porphyria cutanea tarda regarding age of onset, clinical severity, sex distribution, liver function tests and Iron Storage parameters. However, daily alcohol intake and use of oestrogens were reported more frequently in the group of sporadic patients. It was found that women were over-represented in our study.
Adrian Marchetti - One of the best experts on this subject based on the ideXlab platform.
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ferritin is used for Iron Storage in bloom forming marine pennate diatoms
Nature, 2009Co-Authors: Adrian Marchetti, Michael E. P. Murphy, Micaela S Parker, Lauren P Moccia, Angele L Arrieta, Francois Ribalet, Maria T Maldonado, Virginia E ArmbrustAbstract:The non-haem protein ferritin is used by many plants, animals and microorganisms to store Iron in a non-toxic soluble form that can be readily mobilized when required. Ferritin has now been found in the two diatoms, Pseudo-nitzschia and Fragilariopsis, that dominate phytoplankton blooms induced by both natural and artificial oceanic Iron supplementation. This is the first report of ferritin in any member of the Stramenopila, the eukaryote lineage that includes many plankton components including unicellular algae, diatoms and macroalgae. Phylogenetic analysis suggests that ferritin arose in this small subset of diatoms via lateral gene transfer, and it may be key to their success in the 30–40% of ocean waters in which Iron availability is the factor limiting primary productivity. Natural or artificial oceanic Iron supplementation induces blooms that are dominated by pennate diatoms. It is shown that these diatoms contain the Iron Storage protein ferritin, which may explain their success in Iron-limited waters. Primary productivity in 30–40% of the world’s oceans is limited by availability of the micronutrient Iron1,2. Regions with chronically low Iron concentrations are sporadically pulsed with new Iron inputs by way of dust3 or lateral advection from continental margins4. Addition of Iron to surface waters in these areas induces massive phytoplankton blooms dominated primarily by pennate diatoms5,6. Here we provide evidence that the bloom-forming pennate diatoms Pseudo-nitzschia and Fragilariopsis use the Iron-concentrating protein, ferritin, to safely store Iron. Ferritin has not been reported previously in any member of the Stramenopiles, a diverse eukaryotic lineage that includes unicellular algae, macroalgae and plant parasites. Phylogenetic analyses suggest that ferritin may have arisen in this small subset of diatoms through a lateral gene transfer. The crystal structure and functional assays of recombinant ferritin derived from Pseudo-nitzschia multiseries reveal a maxi-ferritin that exhibits ferroxidase activity and binds Iron. The protein is predicted to be targeted to the chloroplast to control the distribution and Storage of Iron for proper functioning of the photosynthetic machinery. Abundance of Pseudo-nitzschia ferritin transcripts is regulated by Iron nutritional status, and is closely tied to the loss and recovery of photosynthetic competence. Enhanced Iron Storage with ferritin allows the oceanic diatom Pseudo-nitzschia granii to undergo several more cell divisions in the absence of Iron than the comparably sized, oceanic centric diatom Thalassiosira oceanica. Ferritin in pennate diatoms probably contributes to their success in chronically low-Iron regions that receive intermittent Iron inputs, and provides an explanation for the importance of these organisms in regulating oceanic CO2 over geological timescales7,8.
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Ferritin is used for Iron Storage in bloom-forming marine pennate diatoms
Nature, 2008Co-Authors: Adrian Marchetti, Michael E. P. Murphy, Micaela S Parker, Lauren P Moccia, Angele L Arrieta, Francois Ribalet, Maria T Maldonado, Ellen O. Lin, E. Virginia ArmbrustAbstract:The non-haem protein ferritin is used by many plants, animals and microorganisms to store Iron in a non-toxic soluble form that can be readily mobilized when required. Ferritin has now been found in the two diatoms, Pseudo-nitzschia and Fragilariopsis, that dominate phytoplankton blooms induced by both natural and artificial oceanic Iron supplementation. This is the first report of ferritin in any member of the Stramenopila, the eukaryote lineage that includes many plankton components including unicellular algae, diatoms and macroalgae. Phylogenetic analysis suggests that ferritin arose in this small subset of diatoms via lateral gene transfer, and it may be key to their success in the 30–40% of ocean waters in which Iron availability is the factor limiting primary productivity. Natural or artificial oceanic Iron supplementation induces blooms that are dominated by pennate diatoms. It is shown that these diatoms contain the Iron Storage protein ferritin, which may explain their success in Iron-limited waters. Primary productivity in 30–40% of the world’s oceans is limited by availability of the micronutrient Iron1,2. Regions with chronically low Iron concentrations are sporadically pulsed with new Iron inputs by way of dust3 or lateral advection from continental margins4. Addition of Iron to surface waters in these areas induces massive phytoplankton blooms dominated primarily by pennate diatoms5,6. Here we provide evidence that the bloom-forming pennate diatoms Pseudo-nitzschia and Fragilariopsis use the Iron-concentrating protein, ferritin, to safely store Iron. Ferritin has not been reported previously in any member of the Stramenopiles, a diverse eukaryotic lineage that includes unicellular algae, macroalgae and plant parasites. Phylogenetic analyses suggest that ferritin may have arisen in this small subset of diatoms through a lateral gene transfer. The crystal structure and functional assays of recombinant ferritin derived from Pseudo-nitzschia multiseries reveal a maxi-ferritin that exhibits ferroxidase activity and binds Iron. The protein is predicted to be targeted to the chloroplast to control the distribution and Storage of Iron for proper functioning of the photosynthetic machinery. Abundance of Pseudo-nitzschia ferritin transcripts is regulated by Iron nutritional status, and is closely tied to the loss and recovery of photosynthetic competence. Enhanced Iron Storage with ferritin allows the oceanic diatom Pseudo-nitzschia granii to undergo several more cell divisions in the absence of Iron than the comparably sized, oceanic centric diatom Thalassiosira oceanica. Ferritin in pennate diatoms probably contributes to their success in chronically low-Iron regions that receive intermittent Iron inputs, and provides an explanation for the importance of these organisms in regulating oceanic CO2 over geological timescales7,8.
Brandon N. Lillie - One of the best experts on this subject based on the ideXlab platform.
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Iron Storage disease (hemochromatosis) and hepcidin response to Iron load in two species of pteropodid fruit bats relative to the common vampire bat.
Journal of comparative physiology. B Biochemical systemic and environmental physiology, 2018Co-Authors: Iga M. Stasiak, Graham J. Crawshaw, Dale A. Smith, Jutta D. Hammermueller, Dorothee Bienzle, Brandon N. LillieAbstract:Hepcidin is the key regulator of Iron homeostasis in the body. Iron Storage disease (hemochromatosis) is a frequent cause of liver disease and mortality in captive Egyptian fruit bats (Rousettus aegyptiacus), but reasons underlying this condition are unknown. Hereditary hemochromatosis in humans is due to deficiency of hepcidin or resistance to the action of hepcidin. Here, we investigated the role of hepcidin in Iron metabolism in one species of pteropodid bat that is prone to Iron Storage disease [Egyptian fruit bat (with and without hemochromatosis)], one species of pteropodid bat where Iron Storage disease is rare [straw-colored fruit bat (Eidolon helvum)], and one species of bat with a natural diet very high in Iron, in which Iron Storage disease is not reported [common vampire bat (Desmodus rotundus)]. Iron challenge via intramuscular injection of Iron dextran resulted in significantly increased liver Iron content and histologic Iron scores in all three species, and increased plasma Iron in Egyptian fruit bats and straw-colored fruit bats. Hepcidin mRNA expression increased in response to Iron administration in healthy Egyptian fruit bats and common vampire bats, but not in straw-colored fruit bats or Egyptian fruit bats with hemochromatosis. Hepcidin gene expression significantly correlated with liver Iron content in Egyptian fruit bats and common vampire bats, and with transferrin saturation and plasma ferritin concentration in Egyptian fruit bats. Induction of hepcidin gene expression in response to Iron challenge is absent in straw-colored fruit bats and in Egyptian fruit bats with hemochromatosis and, relative to common vampire bats and healthy humans, is low in Egyptain fruit bats without hemochromatosis. Limited hepcidin response to Iron challenge may contribute to the increased susceptibility of Egyptian fruit bats to Iron Storage disease.
