Leptothrix species, one of the Fe/Mn-oxidizing bacteria, oxidize Fe(II) and produce extracellular, microtubuar, Fe-encrusted sheaths. Since protein(s) involved in Fe(II) oxidation is excreted from Leptothrix cells, the oxidation from Fe(II) to Fe(III) and subsequent Fe(III) deposition to sheaths have been thought to occur in the vicinity or within the sheaths. Previously, Fe(III) particles gene...

Fe absorption from water-soluble forms of Fe is inversely proportional to Fe status in humans. Whether this is true for poorly soluble Fe compounds is uncertain. Our objectives were therefore (1) to compare the up-regulation of Fe absorption at low Fe status from ferrous sulphate (FS) and ferric pyrophosphate (FPP) and (2) to compare the efficacy of FS with FPP in a fortification trial to incre...

The reaction between aqueous Fe(II) and Fe(III) oxides is extremely complex, and can catalyze Fe(II)-Fe(III) electron transfer, exchange of Fe atoms between the aqueous and solid phases, mineral transformation, and contaminant reduction. Together, these processes represent a phenomenon referred to as Fe(II)-catalyzed Fe oxide recrystallization, which has been observed under controlled condition...

BACKGROUND Our objective was to compare the capacity of iron (Fe) biofortified and standard pearl millet (Pennisetum glaucum L.) to deliver Fe for hemoglobin (Hb)-synthesis. Pearl millet (PM) is common in West-Africa and India, and is well adapted to growing areas characterized by drought, low-soil fertility, and high-temperature. Because of its tolerance to difficult growing conditions, it can...

A continuous culturing system (chemostat) made of metal-free materials was successfully developed and used to maintain Fe-limited cultures of Microcystis aeruginosa PCC7806 at nanomolar iron (Fe) concentrations (20 to 50 nM total Fe). EDTA was used to maintain Fe in solution, with bioavailable Fe controlled by absorption of light by the ferric EDTA complex and resultant reduction of Fe(III) to ...

Hereditary hemochromatosis type 3 is an iron (Fe)-overload disorder caused by mutations in transferrin receptor 2 (TfR2). TfR2 is expressed highly in the liver and regulates Fe metabolism. The aim of this study was to investigate duodenal Fe absorption and hepatic Fe uptake in a TfR2 (Y245X) mutant mouse model of hereditary hemochromatosis type 3. Duodenal Fe absorption and hepatic Fe uptake we...

Recent studies of bacterial Fe(II) oxidation at circumneutral pH by a newly-isolated lithotrophic β-Proteobacterium (strain TW2) are reviewed in relation to a conceptual model that accounts for the influence of biogenic Fe(III)-binding ligands on patterns of Fe(II) oxidation and Fe(III) oxide deposition in opposing gradients of Fe(II) and O2. The conceptual model envisions complexation of Fe(II...

Iron (Fe) and manganese (Mn) are the two most common redox-active elements in the Earth's crust and are well known to influence mineral formation and dissolution, trace metal sequestration, and contaminant transformations in soils and sediments. Here, we characterized the reaction of aqueous Fe(II) with pyrolusite (β-MnO2) using electron microscopy, X-ray diffraction, aqueous Fe and Mn analyses...

A high-performance liquid chromatography-electrospray ionization/mass spectrometry (time of flight) method has been developed for the simultaneous determination of synthetic Fe(III)-chelates used as fertilizers. Analytes included the seven major Fe(III)-chelates used in agriculture, Fe(III)-EDTA, Fe(III)-DTPA, Fe(III)-HEDTA, Fe(III)-CDTA, Fe(III)-o,oEDDHA, Fe(III)-o,pEDDHA, and Fe(III)-EDDHMA, ...

Pseudomonas putida DOT-T1E is able to grow with glucose as the carbon source in liquid medium with 1% (vol/vol) toluene or 17 g of (123 mM) p-hydroxybenzoate (4HBA) per liter. After random mini-Tn5'phoA-Km mutagenesis, we isolated the mutant DOT-T1E-PhoA5, which was more sensitive than the wild type to 4HBA (growth was prevented at 6 g/liter) and toluene (the mutant did not withstand sudden tol...