The Bacterial Response to the Chalcogen Metalloids Se and Te

Zannoni, Davide; Borsetti, Francesca; Harrison, Joe J.; Turner, Raymond J.

doi:10.1016/s0065-2911(07)53001-8

Cited by 143 publications

(164 citation statements)

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“…To date, five broadly distributed, genetically distinct tellurite-resistance determinants have been identified on both chromosomes and plasmids of bacteria (Zannoni et al, 2008). In addition to the broadly distributed tellurite-resistance determinants, several unrelated potential resistance determinants distinct to various bacterial species have also been identified (Zannoni et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…In addition to the broadly distributed tellurite-resistance determinants, several unrelated potential resistance determinants distinct to various bacterial species have also been identified (Zannoni et al, 2008). These latter resistance determinants have been suggested as conferring selective advantages distinct from tellurite resistance, since the presence of the determinant does not correlate with exposure of the organism to tellurite in its natural environment (Zannoni et al, 2008). Indeed, it is now recognized that the so-called tellurite-resistance genes often confer other potentially more biologically relevant phenotypic characteristics and that tellurite resistance may be essentially an artefact (Zannoni et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…These latter resistance determinants have been suggested as conferring selective advantages distinct from tellurite resistance, since the presence of the determinant does not correlate with exposure of the organism to tellurite in its natural environment (Zannoni et al, 2008). Indeed, it is now recognized that the so-called tellurite-resistance genes often confer other potentially more biologically relevant phenotypic characteristics and that tellurite resistance may be essentially an artefact (Zannoni et al, 2008). For example, overproduction of the cysteine biosynthetic pathway can mediate a tellurite-resistance phenotype by conferring resistance to oxidative damage incurred upon tellurite exposure (Tantalean et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the Haemophilus influenzae tehB gene and its role in virulence

et al. 2010

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The Haemophilus influenzae ORF designated HI1275 in the Rd KW20 genomic sequence encodes a putative S-adenosyl methyltransferase with significant similarity to tellurite-resistance determinants (tehB) in other species. While the H. influenzae tehB can complement an Escherichia coli tehB mutation, thus restoring tellurite resistance, its role in H. influenzae is unknown. In a previous study defining the iron and haem modulon of H. influenzae, we showed that transcription of this gene in H. influenzae Rd KW20 increases during growth in iron-and haem-restricted media. Since iron and haem uptake genes, and other known virulence factors, constitute the majority of the iron-and haem-regulated gene set, we postulated that tehB may play a role in nutrient acquisition and/or the virulence of H. influenzae. A tehB mutant was constructed in the H. influenzae type b strain 10810 and was evaluated for growth defects in various supplemented media, as well as for its ability to cause infection in rat models of infection. Deletion of tehB leads to an increase in sensitivity both to tellurite and to the oxidizing agents cumene hydroperoxide, tert-butyl hydroperoxide and hydrogen peroxide. The tehB mutant additionally showed a significantly reduced ability to utilize free haem as well as several haem-containing moieties including haem-human serum albumin, haemoglobin and haemoglobin-haptoglobin. Examination of the regulation kinetics indicated that transcription of tehB was independent of both tellurite exposure and oxidative stress. Paired comparisons of the tehB mutant and the wild-type H. influenzae strain 10810 showed that tehB is required for wild-type levels of infection in rat models of H. influenzae invasive disease. To our knowledge this is the first report of a role for tehB in virulence in any bacterial species. These data demonstrate that H. influenzae tehB plays a role in both resistance to oxidative damage and haem uptake/utilization, protects H. influenzae from tellurite exposure, and is important for virulence of this organism in an animal model of invasive disease.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization of the Haemophilus influenzae tehB gene and its role in virulence

et al. 2010

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“…Tellurite toxicity may be related to its activity as a strong oxidizing agent toward biological materials (17,25,34), although some disagree with this model (40).…”

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confidence: 99%

Aeration Controls the Reduction and Methylation of Tellurium by the Aerobic, Tellurite-Resistant Marine Yeast Rhodotorula mucilaginosa

Ollivier

Bahrou

Church

et al. 2011

Appl Environ Microbiol

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We previously described a marine, tellurite-resistant strain of the yeast Rhodotorula mucilaginosa that both precipitates intracellular Te(0) and volatilizes methylated Te compounds when grown in the presence of the oxyanion tellurite. The uses of microbes as a "green" route for the production of Te(0)-containing nanostructures and for the remediation of Te-oxyanion wastes have great potential, and so a more thorough understanding of this process is required. Here, Te precipitation and volatilization catalyzed by R. mucilaginosa were examined in continuously aerated and sealed (low oxygen concentration) batch cultures. Continuous aeration was found to strongly promote Te volatilization while inhibiting Te(0) precipitation. This differs from the results in sealed batch cultures, for which tellurite reduction to Te(0) was found to be very efficient. We show also that volatile Te species may be degraded rapidly in medium and converted to the particulate form by biological activity. Further experiments revealed that Te(0) precipitates produced by R. mucilaginosa can be further transformed to volatile and dissolved Te species. However, it was not clearly determined whether Te(0) is a required intermediate for Te volatilization. Based on these results, we conclude that low oxygen concentrations will be the most efficient for production of Te(0) nanoparticles while limiting the production of toxic volatile Te species, although the production of these compounds may never be completely eliminated. 9), and there has been interest in the microbial production of Te-containing nanoparticles (3) for applications such as composite or compound nanomaterials in solar cells and as an alternative for bench-scale syntheses. We recently described (26) a series of obligately aerobic, tellurite-resistant microbes isolated from salt marsh sediments that efficiently produce intracellular Te-containing nanostructures in a complex growth medium without any specialized growth requirements. The same strains also volatilized a small proportion of the supplied Te as methylated species. Here we further describe the interactions of one of these organisms, the yeast Rhodotorula mucilaginosa, with Te and how these interactions are modulated by aeration.In aerobic soils and aquatic environments, tellurium occurs primarily as the tellurite [TeO 3 2Ϫ or Te(IV)] and tellurate [TeO 4 2Ϫ or Te(VI)] oxyanions. While tellurite is the most water soluble, both are freely available to living organisms.Tellurite has been employed as an antimicrobial therapeutic agent (31, 34), and it is about 10 times more toxic to both Gram-positive and Gram-negative microorganisms than tellurate (37, 39). Tellurite toxicity may be related to its activity as a strong oxidizing agent toward biological materials (17,25,34), although some disagree with this model (40).Microbial tellurite resistance is a widespread phenomenon. In most environments sampled to date, tellurite-resistant organisms comprise ϳ10% of the total culturable microbial population (26,28,32,34). Resistan...

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