Iron and manganese transport in mammalian systems

ABSTRACT The increased serum survival gene iss has long been recognized for its role in extraintestinal pathogenic Escherichia coli (ExPEC) virulence. iss has been identified as a distinguishing trait of avian ExPEC but not of human ExPEC. This gene has been localized to large virulence plasmids and shares strong similarities with the bor gene from bacteriophage λ. Here, we demonstrate that three alleles of iss occur among E. coli isolates that appear to have evolved from a common λ bor precursor. In addition to the occurrence of iss on the ColV/BM virulence plasmids, at least two iss alleles occur within the E. coli chromosome. One of these alleles (designated type 3) was found to occur in the genomes of all currently sequenced ExPEC strains on a similar prophage element that also harbors the Sit iron and manganese transport system. When the prevalence of the three iss types was examined among 487 E. coli isolates, the iss type 3 gene was found to occur at a high frequency among ExPEC isolates, irrespective of the host source. The plasmid-borne iss allele (designated type 1) was highly prevalent among avian pathogenic E. coli and neonatal meningitis-associated E. coli isolates but not among uropathogenic E. coli isolates. This study demonstrates the evolution of iss in E. coli and provides an additional tool for discriminating among E. coli pathotypes through the differentiation of the three iss allele types and bor.

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Yersinia pestis TonB: Role in Iron, Heme, and Hemoprotein Utilization

Infection and Immunity ◽

10.1128/iai.71.7.4159-4162.2003 ◽

2003 ◽

Vol 71 (7) ◽

pp. 4159-4162 ◽

Cited By ~ 20

Author(s):

Robert D. Perry ◽

Jessica Shah ◽

Scott W. Bearden ◽

Jan M. Thompson ◽

Jacqueline D. Fetherston

Keyword(s):

Yersinia Pestis ◽

Outer Membrane ◽

Transport System ◽

Iron Transport ◽

Membrane Receptors ◽

Heme Transport ◽

Iron Heme ◽

Manganese Transport ◽

Iron Utilization ◽

Iron And Manganese

ABSTRACT In Yersinia pestis, the siderophore-dependent yersiniabactin (Ybt) iron transport system and heme transport system (Hmu) have putative TonB-dependent outer membrane receptors. Here we demonstrate that hemin uptake and iron utilization from Ybt are TonB dependent. However, the Yfe iron and manganese transport system does not require TonB.

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Agrobacterium tumefaciens fur Has Important Physiological Roles in Iron and Manganese Homeostasis, the Oxidative Stress Response, and Full Virulence

Applied and Environmental Microbiology ◽

10.1128/aem.00531-07 ◽

2007 ◽

Vol 73 (15) ◽

pp. 4760-4768 ◽

Cited By ~ 47

Author(s):

Worawan Kitphati ◽

Patchara Ngok-ngam ◽

Sukanya Suwanmaneerat ◽

Rojana Sukchawalit ◽

Skorn Mongkolsuk

Keyword(s):

Agrobacterium Tumefaciens ◽

Physiological Role ◽

Iron Chelator ◽

Wild Type ◽

Manganese Uptake ◽

Oxidative Resistance ◽

Virulence Assay ◽

Manganese Transport ◽

Iron And Manganese

ABSTRACT In Agrobacterium tumefaciens, the balance between acquiring enough iron and avoiding iron-induced toxicity is regulated in part by Fur (ferric uptake regulator). A fur mutant was constructed to address the physiological role of the regulator. Atypically, the mutant did not show alterations in the levels of siderophore biosynthesis and the expression of iron transport genes. However, the fur mutant was more sensitive than the wild type to an iron chelator, 2,2′-dipyridyl, and was also more resistant to an iron-activated antibiotic, streptonigrin, suggesting that Fur has a role in regulating iron concentrations. A. tumefaciens sitA, the periplasmic binding protein of a putative ABC-type iron and manganese transport system (sitABCD), was strongly repressed by Mn2+ and, to a lesser extent, by Fe2+, and this regulation was Fur dependent. Moreover, the fur mutant was more sensitive to manganese than the wild type. This was consistent with the fact that the fur mutant showed constitutive up-expression of the manganese uptake sit operon. FurAt showed a regulatory role under iron-limiting conditions. Furthermore, Fur has a role in determining oxidative resistance levels. The fur mutant was hypersensitive to hydrogen peroxide and had reduced catalase activity. The virulence assay showed that the fur mutant had a reduced ability to cause tumors on tobacco leaves compared to wild-type NTL4.

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Colloidal systems in soils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168050 ◽

1994 ◽

Vol 52 ◽

pp. 64-65

Author(s):

J. Thieme ◽

J. Niemeyer ◽

P. Guttman

Keyword(s):

Clay Minerals ◽

Polymeric Materials ◽

Spatial Arrangement ◽

High Specific Surface Area ◽

Turnover Rates ◽

Colloidal Systems ◽

Chemical Conditions ◽

Aggregation Phenomena ◽

Iron And Manganese ◽

Soil Colloids

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.

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The content of copper, zinc, iron and manganese in honey

Annales UMCS Pharmacia ◽

10.2478/v10080-008-0010-4 ◽

2008 ◽

Vol 21 (1) ◽

pp. 77-80

Author(s):

Andrzej Kot ◽

Stanisław Zaręba

Keyword(s):

Copper Zinc ◽

Iron And Manganese

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Iron and Manganese -- Preliminary report on the red iron ores of east Tennessee, northeast Alabama, and northwest Georgia

10.3133/b540g ◽

1914 ◽

Keyword(s):

Preliminary Report ◽

Iron Ores ◽

East Tennessee ◽

Iron And Manganese

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Best Practice Guide on the Control of Iron and Manganese in Water Supply

Water Intelligence Online ◽

10.2166/9781780400747 ◽

2013 ◽

Vol 12 ◽

Cited By ~ 8

Author(s):

Adam Postawa

Keyword(s):

Water Supply ◽

Best Practice ◽

Practice Guide ◽

Iron And Manganese

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Chemical effects on UV irradiation absorption of fouled quartz sleeves in ultraviolet disinfection

Water Science & Technology Water Supply ◽

10.2166/ws.2008.064 ◽

2008 ◽

Vol 8 (2) ◽

pp. 217-222 ◽

Cited By ~ 1

Author(s):

Beibei Zhu Sun ◽

Ernest Blatchley ◽

Mike Oliver ◽

Cheng Zheng ◽

Kristofer Jennings

Keyword(s):

Statistical Analysis ◽

Uv Disinfection ◽

Uv Absorbance ◽

Ultraviolet Disinfection ◽

High Chemical ◽

Chemical Surface ◽

Chemical Effects ◽

Uv Transmittance ◽

Main Effects ◽

Iron And Manganese

The effects of foulant chemical composition on ultraviolet (UV) absorbance of fouled quartz sleeves in UV disinfection systems were studied. Statistical analysis was conducted to examine the effects of nine fouling chemicals on the UV transmittance changes of fouled quartz lamp sleeves. The results demonstrated that the main effects were attributable to surface concentrations of iron and manganese. The surface concentrations of calcium and copper had no significant effects on the UV absorbance of fouled sleeves. The interaction effects of copper with iron and magnesium with manganese were also revealed from the statistical analysis. The model is able to give reasonable predictions of the UV absorbance characteristics of foulants from other UV systems. However, several limitations of this model were identified. First, the model does not accurately predict the absorbance at relatively high chemical surface concentrations. Second, the model does not account for the possible effects of anions and organics on UV absorption of fouled quartz sleeves.

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Investigation into Mechanisms of Microbial Effects on Iron and Manganese Transformations in Artificially Recharged Groundwater

Water Science & Technology ◽

10.2166/wst.1988.0080 ◽

1988 ◽

Vol 20 (3) ◽

pp. 47-53 ◽

Cited By ~ 1

Author(s):

Yan Bao-rui

Keyword(s):

Groundwater Quality ◽

Biochemical Reaction ◽

Reaction Products ◽

Injection Wells ◽

Iron Bacteria ◽

Sulphate Reducing Bacteria ◽

Prevention And Treatment ◽

Reducing Bacteria ◽

Iron And Manganese ◽

Microbial Effects

After artificial recharging of groundwater some problems occurred, such as changes in groundwater quality, the silting up of recharge (injection) wells, etc. Therefore, the mechanisms of microbial effects on groundwater quality after artificial recharging were studied in Shanghai and the district of Changzhou. These problems were approached on the basis of the amounts of biochemical reaction products generated by the metabolism of iron bacteria, sulphate-reducing bacteria, Thiobacillusthioparus, and Thiobacillusdenitrificans. The experiments showed that in the transformations occurring and the siltation of recharge wells, microorganisms play an important role, due to the various chemical and biochemical activities. A water-rock-microorganisms system is proposed, and some methods for the prevention and treatment of these effects are given.

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