Essential and Toxic Effects of Elements on Microorganisms

Nies, Dietrich H.

doi:10.1002/9783527619634.ch13

Cited by 15 publications

(13 citation statements)

References 166 publications

(91 reference statements)

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“…Hence, the widespread distribution of CDF group 3 members in bacteria (37) may mirror the high importance of iron over other divalent heavy metal cations (38).…”

Section: Discussionmentioning

confidence: 99%

The Chromosomally Encoded Cation Diffusion Facilitator Proteins DmeF and FieF from Wautersia metallidurans CH34 Are Transporters of Broad Metal Specificity

2004

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Genomic sequencing of the ␤-proteobacterium Wautersia (previously Ralstonia) metallidurans CH34 revealed the presence of three genes encoding proteins of the cation diffusion facilitator (CDF) family. One, CzcD, was previously found to be part of the high-level metal resistance system Czc that mediates the efflux of Co(II), Zn(II), and Cd(II) ions catalyzed by the CzcCBA cation-proton antiporter. The second CDF protein, FieF, is probably mainly a ferrous iron detoxifying protein but also mediated some resistance against other divalent metal cations such as Zn(II), Co(II), Cd(II), and Ni(II) in W. metallidurans or Escherichia coli. The third CDF protein, DmeF, showed the same substrate spectrum as FieF, but with different preferences. DmeF plays the central role in cobalt homeostasis in W. metallidurans, and a disruption of dmeF rendered the high-level metal cation resistance systems Czc and Cnr ineffective against Co(II). This is evidence for the periplasmic detoxification of substrates by RND transporters of the heavy metal efflux family subgroup. (34,41,45). These transporters were initially identified as Co(II) or Zn(II) transporters (5, 36), but the family was subsequently shown to be able to transport Cd(II) (1, 18), Mn(II) (6), Ni(II) (46), or Fe(II) (12, 27) as well. For the zinc-and cadmium-transporting CDF protein CzcD from Bacillus subtilis, it was demonstrated that the mechanism of transport is electroneutral antiporting of the metal cation against H ϩ or K ϩ (18). Recently, kinetic parameters for transport for the Zn(II)-effluxing CDF ZitB from Escherichia coli were experimentally determined, suggesting that the ratio of Zn(II) to H ϩ is 1:1 and thus not electroneutral (3).The first characterized bacterial member of the CDF family, CzcD (36) from W. metallidurans, was shown to mediate the efflux of Cd(II), Zn(II), and Co(II) (1). The Czc system also comprises another tripartite efflux machinery, CzcCBA, that spans the cytoplasmic and outer membranes and mediates high-level resistance against Cd(II), Zn(II), and Co(II) by active efflux driven by the proton motive force (9, 35).Recently, the complete genome of W. metallidurans was made available. An analysis revealed the presence of two additional genes for CDF proteins in this organism. In contrast to czcD, these open reading frames are not located on one of the two indigenous megaplasmids (pMOL28 and pMOL30) but are carried by the bacterial chromosome. The first, named dmeF (divalent metal efflux), is located on contig 366 (gene number 7456), and the second, named fieF (ferrous iron efflux) after its orthologue from E. coli (12), is located on contig 369 (gene number 9480) (nomenclature is according to the web site http://www.genome.jgi-psf.org/draft_microbes/ralme/ralme.home .html).Using (28,35). This suggests that RND systems utilize Co(II) only from the periplasm and thus that RND-driven transport occurs from the periplasm rather than from the cytoplasm to the outside. MATERIALS AND METHODSBacterial strains and growth conditions. E. coli was gro...

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“…Hence, the widespread distribution of CDF group 3 members in bacteria (37) may mirror the high importance of iron over other divalent heavy metal cations (38).…”

Section: Discussionmentioning

confidence: 99%

The Chromosomally Encoded Cation Diffusion Facilitator Proteins DmeF and FieF from Wautersia metallidurans CH34 Are Transporters of Broad Metal Specificity

2004

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“…Mercury is a toxic metal with no known biological function because its affinity to thiol compounds is so high that it disrupts protein structure and function (18). Bacteria are involved in the global environmental cycling of mercury.…”

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confidence: 99%

Curli Produced by Escherichia coli PHL628 Provide Protection from Hg(II)

Hidalgo

Chen

Lion

2010

Appl Environ Microbiol

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“…Table 1. Macro-elements content in marine and terrestrial plants and animals, and bacteria (in grams to 100 g dry matter), modified after Barabanov [12] The distribution of macro-and micronutrients in different types of bedrock, soils, plants and animals have been studies intensively for more than 50 years, but due to the large ranges in composition, no consensus has been reached on the precise abundances of essential trace element concentrations in living organisms [9][10][13][14][15][16][17][18][19][20][21][22]. The reason for this is that micronutrients are present and needed in very small amounts.…”

Section: Distribution Of Chemical Elements In the Biosphere Of The Earthmentioning

confidence: 99%

The Influence of Geochemistry on Biological Diversity in Fennoscandia and Estonia

Systra¹

2012

Biodiversity Enrichment in a Diverse World

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Essential and Toxic Effects of Elements on Microorganisms

Cited by 15 publications

References 166 publications

The Chromosomally Encoded Cation Diffusion Facilitator Proteins DmeF and FieF from Wautersia metallidurans CH34 Are Transporters of Broad Metal Specificity

The Chromosomally Encoded Cation Diffusion Facilitator Proteins DmeF and FieF from Wautersia metallidurans CH34 Are Transporters of Broad Metal Specificity

Curli Produced by Escherichia coli PHL628 Provide Protection from Hg(II)

The Influence of Geochemistry on Biological Diversity in Fennoscandia and Estonia

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