Enzyme Control Over Ferric Iron Magnetostructural Properties

Abstract Background Halotolerant Fe (III) oxide reducers affiliated in the family Desulfuromonadaceae are ubiquitous and drive the carbon, nitrogen, sulfur and metal cycles in marine subsurface sediment. Due to their possible application in bioremediation and bioelectrochemical engineering, some of phylogenetically close Desulfuromonas spp. strains have been isolated through enrichment with crystalline Fe (III) oxide and anode. The strains isolated using electron acceptors with distinct redox potentials may have different abilities, for instance, of extracellular electron transport, surface recognition and colonization. The objective of this study was to identify the different genomic signatures between the crystalline Fe (III) oxide-stimulated strain AOP6 and the anode-stimulated strains WTL and DDH964 by comparative genome analysis. Results The AOP6 genome possessed the flagellar biosynthesis gene cluster, as well as diverse and abundant genes involved in chemotaxis sensory systems and c-type cytochromes capable of reduction of electron acceptors with low redox potentials. The WTL and DDH964 genomes lacked the flagellar biosynthesis cluster and exhibited a massive expansion of transposable gene elements that might mediate genome rearrangement, while they were deficient in some of the chemotaxis and cytochrome genes and included the genes for oxygen resistance. Conclusions Our results revealed the genomic signatures distinctive for the ferric iron oxide- and anode-stimulated Desulfuromonas spp. strains. These findings highlighted the different metabolic abilities, such as extracellular electron transfer and environmental stress resistance, of these phylogenetically close bacterial strains, casting light on genome evolution of the subsurface Fe (III) oxide reducers.

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III.—On the Reduction of Ferric Iron (1) by Sulphurous Acid and (2) by Zinc Dust

Proceedings of the Royal Society of Edinburgh ◽

10.1017/s0370164600012736 ◽

1913 ◽

Vol 32 ◽

pp. 12-16

Author(s):

Alexander Charles Cumming ◽

E. W. Hamilton Smith

Keyword(s):

Sulphuric Acid ◽

Carbonate Rocks ◽

Ferric Iron ◽

Zinc Dust ◽

The Other ◽

Additional Contribution ◽

Large Excess ◽

Other Hand

So many papers have appeared on this subject that some apology seems desirable before making an additional contribution. The amount of published work on reduction with sulphurous acid is in itself an indication that many workers have found difficulties. It has been shown that the reduction does not take place in presence of large excess of hydrochloric or sulphuric acid, but the reduction will still occur while the reaction of the solution is strongly acid. On the other hand, Hillebrand (“Analysis of Silicate and Carbonate Rocks,” U.S. Bulletin, 442, p. 113) states if the solution after addition of sulphite is red in colour, it is too alkaline and acid must be added.

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Cutaneous wound healing is impaired in hemophilia B

Blood ◽

10.1182/blood-2006-05-020495 ◽

2006 ◽

Vol 108 (9) ◽

pp. 3053-3060 ◽

Cited By ~ 74

Author(s):

Maureane Hoffman ◽

Anna Harger ◽

Angela Lenkowski ◽

Ulla Hedner ◽

Harold R. Roberts ◽

...

Keyword(s):

Wound Healing ◽

Time Course ◽

Ferric Iron ◽

Hemophilia B ◽

Cutaneous Wound Healing ◽

Delayed Wound Healing ◽

Cutaneous Wound ◽

Time Points ◽

Hemophilic Arthropathy ◽

Healing Wounds

Abstract We used a mouse model to test the hypothesis that the time course and histology of wound healing is altered in hemophilia B. Punch biopsies (3 mm) were placed in the skin of normal mice and mice with hemophilia. The size of the wounds was measured daily until the epidermal defect closed. All wounds closed in mice with hemophilia by 12 days, compared with 10 days in normal animals. Skin from the area of the wound was harvested at different time points and examined histologically. Hemophilic animals developed subcutaneous hematomas; normal animals did not. Macrophage infiltration was significantly delayed in hemophilia B. Unexpectedly, hemophilic mice developed twice as many blood vessels in the healing wounds as controls, and the increased vascularity persisted for at least 2 weeks. The deposition and persistence of ferric iron was also greater in hemophilic mice. We hypothesize that iron plays a role in promoting excess angiogenesis after wounding as it had been proposed to do in hemophilic arthropathy. We have demonstrated that impaired coagulation leads to delayed wound healing with abnormal histology. Our findings have significant implications for treatment of patients with hemophilia, and also highlight the importance of rapidly establishing hemostasis following trauma or surgery.

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Thermodynamic Simulation of Sulphide Mineral Leaching

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.71-73.437 ◽

2009 ◽

Vol 71-73 ◽

pp. 437-440

Author(s):

Lasse Ahonen ◽

Pauliina Nurmi ◽

Olli H. Tuovinen

Keyword(s):

Acid Solution ◽

Ferric Iron ◽

Geochemical Modeling ◽

Thermodynamic Simulation ◽

Sulphide Mineral ◽

Solution Ph ◽

Dissolved Iron ◽

Iron Precipitation ◽

Oxidative Leaching ◽

Mineral Leaching

Geochemical modeling program PHREEQC was used to simulate generic bioleaching processes. Carbonate minerals (e.g., calcite) dissolve in acid solution, increasing the solution pH and Ca concentration while the concentration of CO2 may be controlled by the equilibrium with the atmospheric CO2. Non-oxidative dissolution of Fe-monosulphides was demonstrated to release H2S and increase the pH. In the absence of ferric iron precipitation (goethite), the oxidation of pyrite decreased the solution pH from 2 to ~1.4, while the oxidation of Fe-monosulphide and chalcopyrite increased the solution pH to ~3.2-3.4. Assuming equilibrium precipitation of goethite, oxidative leaching decreased the solution pH for all three minerals from pH ~2 to ~0.9-1.2. Adjustment of the solution pH to 1.8 or 2.0 with KOH with concurrent equilibrium precipitation of K-jarosite resulted in low dissolved iron concentrations.

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