Examples of iron in the following topics:
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- Iron (Fe) follows a geochemical cycle like many other nutrients.
- The Terrestrial Iron Cycle: In terrestrial ecosystems, plants first absorb iron through their roots from the soil.
- Iron is required to produce chlorophyl, and plants require sufficient iron to perform photosynthesis.
- Animals acquire iron when they consume plants, and iron is utilized by vertebrates in hemoglobin, the oxygen-binding protein found in red blood cells.
- The Marine Iron Cycle: The oceanic iron cycle is similar to the terrestrial iron cycle, except that the primary producers that absorb iron are typically phytoplankton or cyanobacteria.
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- Ferric iron is an anaerobic terminal electron acceptor, with the final enzyme a ferric iron reductase.
- Since some ferric iron-reducing bacteria (e.g.
- Ferrous iron is a soluble form of iron that is stable at extremely low pHs or under anaerobic conditions.
- There are three distinct types of ferrous iron-oxidizing microbes.
- Outline the purpose of iron oxidation and the three types of ferrous iron-oxidizing microbes (acidophiles, microaerophiles and anaerobic photosynthetic bacteria)
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- Siderophores produce specific proteins and some siderophores form soluble iron complexes to aid in iron acquisition for survival.
- The siderophores are then utilized by the pathogen to obtain iron.
- Therefore, siderophores are chelating agents that bind the iron ions.
- In iron deficient environments, the siderophores are released and allow for the formation of water soluble-Fe3+ complexes to increase iron acquisition.
- The iron will then be utilized in numerous cellular processes.
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- Iron-binding proteins are proteins generally used to play roles in metabolism.
- Iron-binding proteins are serum proteins, found in the blood, and as their name suggests, are used to bind and transport iron.
- Transferrins are iron-binding blood plasma glycoproteins that control the level of free iron in biological fluids .
- Transferrin glycoproteins bind iron very tightly, but reversibly.
- Although iron bound to transferrin is less than 0.1% (4 mg) of the total body iron, it is the most important iron pool, with the highest rate of turnover (25 mg/24 h).
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- However, iron is not always readily available; therefore, microorganisms use various iron uptake systems to secure sufficient supplies from their surroundings.
- There is considerable variation in the range of iron transporters and iron sources utilized by different microbial species.
- Pathogens, in particular, require efficient iron acquisition mechanisms to enable them to compete successfully for iron in the highly iron-restricted environment of the host's tissues and body fluids.
- For example, the anthrax pathogen Bacillus anthracis releases two siderophores, bacillibactin and petrobactin, to scavenge ferric iron from iron proteins.
- Siderophores are usually classified by the ligands used to chelate the ferric iron.
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- Ores, like pyrite (FeS2), are first oxidized by ferric iron (Fe3+) to thiosulfate (S2O32-) in the absence of bacteria.
- In the first step, disulfide is spontaneously oxidized to thiosulfate by ferric iron (Fe3+), which in turn is reduced to give ferrous iron (Fe2+):
- (2)$4 \ Fe^{\,2+} + \ O_2 + 4 \ H^+ \longrightarrow 4 \ Fe^{\,3+} + 2 \ H_2O$ (iron oxidizers)
- The critical reaction is the oxidation of sulfide by ferric iron.
- Bacterial cells oxidizing the ferrous iron back to ferric iron while using slightly different contact mechanisms with the metal.
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- Many denitrifying bacteria can also use ferric iron (Fe3+) and different organic electron acceptors.
- Ferric iron (Fe3+) is a widespread anaerobic terminal electron acceptor used by both autotrophic and heterotrophic organisms.
- Electron flow in these organisms is similar to those in electron transport, ending in oxygen or nitrate, except that in ferric iron-reducing organisms the final enzyme in this system is a ferric iron reductase.
- Since some ferric iron-reducing bacteria (e.g.G. metallireducens) can use toxic hydrocarbons (e.g. toluene) as a carbon source, there is significant interest in using these organisms as bioremediation agents in ferric iron contaminated aquifers.
- Describe various types of electron acceptors and donors including: nitrate, sulfate, hydrgoen, carbon dioxide and ferric iron
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- Magnetotactic bacteria usually mineralize either iron oxide magnetosomes , which contain crystals of magnetite (Fe3O4), or iron sulfide magnetosomes, which contain crystals of greigite (Fe3S4).
- Several other iron sulfide minerals have also been identified in iron sulfide magnetosomes — including mackinawite (tetragonal FeS) and a cubic FeS — which are thought to be precursors of Fe3S4.
- One type of magnetotactic bacterium present at the oxic-anoxic transition zone (OATZ) of the southern basin of the Pettaquamscutt River Estuary, Narragansett, Rhode Island is known to produce both iron oxide and iron sulfide magnetosomes.
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- ., the iron(III) chloride complex (TPPFeCl), catalyze a variety of reactions in organic synthesis.
- For example, complexes of meso-tetraphenylporphyrin, e.g., the iron(III) chloride complex (TPPFeCl), catalyze a variety of reactions of potential interest in organic synthesis.
- Some iron-containing porphyrins are called hemes.
- Hemoglobin and myoglobin are two O2-binding proteins that contain iron porphyrins.
- Intermediates are used in different species to form particular substances, but, in humans, the main end-product protoporphyrin IX is combined with iron to form heme.
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- Chemotrophs are a class of organisms that obtain their energy through the oxidation of inorganic molecules, such as iron and magnesium.
- The energy required for this process comes from the oxidation of inorganic molecules such as iron, sulfur or magnesium.
- Chemoautotrophs include nitrogen fixing bacteria located in the soil, iron oxidizing bacteria located in the lava beds, and sulfur oxidizing bacteria located in deep sea thermal vents.