The membrane-bound respiratory chain of Pseudomonas pseudoalcaligenes KF707 cells grown in the presence or absence of potassium tellurite This work is dedicated to my friend and colleague Franco Tatò, prematurely deceased on 7 July 2001.

Tomaso, Giovanna Di; Fedi, Stefano; Carnevali, Monica; Manegatti, Marco; Taddei, Carlo; Zannoni, Davide

doi:10.1099/00221287-148-6-1699

Cited by 49 publications

(35 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, initiation of accumulation of Te(0) coincided with the switch from fermentative to respiratory metabolism in S. cerevisiae and respiring yeast cells were hypersensitive to Te(IV). These observations agree well with observations on Pseudomonas aeruginosa and P. pseudoalcaligenes which show that the rate of Te(IV) reduction is strongly correlated with the rate of respiration, that inhibition of respiration partially inhibits Te(IV) reduction, and that Te(IV) exposure induces changes in multiple components of the respiratory chain (13,59). Hence, our results identified two cellular routes as key to the intracellular fate of Te species in yeast: sulfate assimilation and a mitochondrial mechanism that encompasses respiration.…”

Section: Discussionsupporting

confidence: 82%

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

et al. 2010

View full text Add to dashboard Cite

Despite a century of research and increasing environmental and human health concerns, the mechanistic basis of the toxicity of derivatives of the metalloid tellurium, Te, in particular the oxyanion tellurite, Te(IV), remains unsolved. Here, we provide an unbiased view of the mechanisms of tellurium metabolism in the yeast Saccharomyces cerevisiae by measuring deviations in Te-related traits of a complete collection of gene knockout mutants. Reduction of Te(IV) and intracellular accumulation as metallic tellurium strongly correlated with loss of cellular fitness, suggesting that Te(IV) reduction and toxicity are causally linked. The sulfate assimilation pathway upstream of Met17, in particular, the sulfite reductase and its cofactor siroheme, was shown to be central to tellurite toxicity and its reduction to elemental tellurium. Gene knockout mutants with altered Te(IV) tolerance also showed a similar deviation in tolerance to both selenite and, interestingly, selenomethionine, suggesting that the toxicity of these agents stems from a common mechanism. We also show that Te(IV) reduction and toxicity in yeast is partially mediated via a mitochondrial respiratory mechanism that does not encompass the generation of substantial oxidative stress. The results reported here represent a robust base from which to attack the mechanistic details of Te(IV) toxicity and reduction in a eukaryotic organism.

show abstract

Section: Discussionsupporting

confidence: 82%

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The reduction of tellurite by chemotrophically grown cells of E. coli, Erwinia carotovora, and Agrobacterium tumefaciens has been related to the activity and membrane location and sidedness of the respiratory cytochrome oxidases (Cox), although the stimulation of Cox activity in cells of P. aeruginosa was seen to lower the cell Te 0 content (39). The latter evidence is clearly in contrast with a role of Cox in TeO 3 2Ϫ reduction but conversely is in line with other reports indicating that Cox activity in cells of Pseudomonas pseudoalcaligenes KF707 and Rhodobacter capsulatus grown in the presence of tellurite drops in parallel with a cytosolic accumulation of Te 0 and a drastic decrease of the c-type cytochrome (Cyt c) content (4,17). These observations led Borsetti et al (4) to suggest that the respiratory Cox oxidases of R. capsulatus and P. pseudoalcaligenes were not involved in the reduction of tellurite to Te 0 .…”

contrasting

confidence: 54%

The Thiol:Disulfide Oxidoreductase DsbB Mediates the Oxidizing Effects of the Toxic Metalloid Tellurite (TeO₃²⁻) on the Plasma Membrane Redox System of the Facultative PhototrophRhodobacter capsulatus

et al. 2007

Self Cite

View full text Add to dashboard Cite

The highly toxic oxyanion tellurite (TeO 3 2؊ ) is a well known pro-oxidant in mammalian and bacterial cells. This work examines the effects of tellurite on the redox state of the electron transport chain of the facultative phototroph Rhodobacter capsulatus, in relation to the role of the thiol:disulfide oxidoreductase DsbB. Under steady-state respiration, the addition of tellurite (2.5 mM) to membrane fragments generated an extrareduction of the cytochrome pool (c-and b-type hemes); further, in plasma membranes exposed to tellurite (0.25 to 2.5 mM) and subjected to a series of flashes of light, the rate of the QH 2 :cytochrome c (Cyt c) oxidoreductase activity was enhanced. The effect of tellurite was blocked by the antibiotics antimycin A and/or myxothiazol, specific inhibitors of the QH 2 :Cyt c oxidoreductase, and, most interestingly, the membrane-associated thiol: disulfide oxidoreductase DsbB was required to mediate the redox unbalance produced by the oxyanion. Indeed, this phenomenon was absent from R. capsulatus MD22, a DsbB-deficient mutant, whereas the tellurite effect was present in membranes from MD22/pDsbB WT , in which the mutant gene was complemented to regain the wild-type DsbB phenotype. These findings were taken as evidence that the membrane-bound thiol:disulfide oxidoreductase DsbB acts as an "electron conduit" between the hydrophilic metalloid and the lipid-embedded Q pool, so that in habitats contaminated with subinhibitory amounts of Te IV , the metalloid is likely to function as a disposal for the excess reducing power at the Q-pool level of facultative phototrophic bacteria.In the environment, tellurium (Te) exists in its elementalTe 0 -inorganic-telluride (Te 2Ϫ ), tellurite (TeO 3 2Ϫ ), and tellurate (TeO 4 2Ϫ )-and organic-dimethyl telluride (CH 3 TeCH 3 )-forms (8). Of these, the toxic oxyanion forms, TeO 3 2Ϫ and TeO 4 2Ϫ , are more common than and are highly soluble compared to nontoxic elemental tellurium, Te 0 (38). Tellurium is widely used in the electronics industry, for photoreceptors, thermocouples, and batteries, but also in metallurgical processes and as an additive to industrial glasses (8). As a result, microorganisms are now becoming exposed to abnormal concentrations of this element, and bacterial species resistant to tellurium can easily be isolated from industrial sludge (38). However, research into the anthropogenic emission of Tebased compounds is scarce, and the implications for selection of microorganisms resistant to tellurite (TeO 3 2Ϫ ) and tellurate (TeO 4 2Ϫ ) are largely unexplored (40). Tellurite is more toxic to mammalian cells (43) and microorganisms (38) than are several heavy metals, e.g., mercury, cadmium, zinc, chromium, and cobalt, which are objects of major public health concern (38). Depending on the strain, the concentration of tellurite inhibiting microbial growth ranges from 1 to 1,000 g/ml (34,38,(46)(47)(48). Microorganisms counteract tellurite (TeO 3 2Ϫ ) toxicity in several ways, namely, by (i) decreasing its uptake, (ii) enhancing its effl...

show abstract

“…The oxyanions of tellurium, tellurite (K 2 TeO 3 ) and tellurate, are highly toxic for most micro-organisms, causing direct oxidation of cellular thiols (Taylor, 1999;Turner et al, 1999) or, following reduction to telluride, is inappropriately incorporated in place of sulfur in amino acids (Garberg et al, 1999;Taylor, 1999). Tellurite can also be reduced to the metal by nitrate reductase (Avazeri et al, 1997) or the terminal oxidases of most Gram-negative bacteria (Trutko et al, 2000;Di Tomaso et al, 2002). Resistant bacteria produce jet-black colonies on solid medium supplemented with K 2 TeO 3 as the result of internal deposition of elemental tellurium (Hill et al, 1993;Whelan et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

An inducible tellurite-resistance operon in Proteus mirabilis

et al. 2003

View full text Add to dashboard Cite

Tellurite resistance (Te r ) is widespread in nature and it is shown here that the natural resistance of Proteus mirabilis to tellurite is due to a chromosomally located orthologue of plasmid-borne ter genes found in enteric bacteria. The P. mirabilis ter locus (terZABCDE) was identified in a screen of Tn5lacZ-generated mutants of which one contained an insertion in terC. The P. mirabilis terC mutant displayed increased susceptibility to tellurite (Te s ) and complementation with terC carried on a multicopy plasmid restored high-level Te r . Primer extension analysis revealed a single transcriptional start site upstream of terZ, but only with RNA harvested from bacteria grown in the presence of tellurite. Northern blotting and reverse transcriptase-PCR (RT-PCR) analyses confirmed that the ter operon was inducible by tellurite and to a lesser extent by oxidative stress inducers such as hydrogen peroxide and methyl viologen (paraquat). Direct and inverted repeat sequences were identified in the ter promoter region as well as motifs upstream of the 235 hexamer that resembled OxyR-binding sequences. Finally, the 390 bp intergenic promoter region located between orf3 and terZ showed no DNA sequence identity with any other published ter sequences, whereas terZABCDE genes exhibited 73-85 % DNA sequence identity. The ter operon was present in all clinical isolates of P. mirabilis and Proteus vulgaris tested and is inferred for Morganella and Providencia spp. based on screening for high level Te r and preliminary PCR analysis. Thus, a chromosomally located inducible tellurite resistance operon appears to be a common feature of the genus Proteus.

show abstract

The membrane-bound respiratory chain of Pseudomonas pseudoalcaligenes KF707 cells grown in the presence or absence of potassium tellurite This work is dedicated to my friend and colleague Franco Tatò, prematurely deceased on 7 July 2001.

Cited by 49 publications

References 28 publications

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

The Thiol:Disulfide Oxidoreductase DsbB Mediates the Oxidizing Effects of the Toxic Metalloid Tellurite (TeO₃²⁻) on the Plasma Membrane Redox System of the Facultative PhototrophRhodobacter capsulatus

An inducible tellurite-resistance operon in Proteus mirabilis

Contact Info

Product

Resources

About

The membrane-bound respiratory chain of Pseudomonas pseudoalcaligenes KF707 cells grown in the presence or absence of potassium tellurite This work is dedicated to my friend and colleague Franco Tatò, prematurely deceased on 7 July 2001.

Cited by 49 publications

References 28 publications

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

The Thiol:Disulfide Oxidoreductase DsbB Mediates the Oxidizing Effects of the Toxic Metalloid Tellurite (TeO32−) on the Plasma Membrane Redox System of the Facultative PhototrophRhodobacter capsulatus

An inducible tellurite-resistance operon in Proteus mirabilis

Contact Info

Product

Resources

About

The Thiol:Disulfide Oxidoreductase DsbB Mediates the Oxidizing Effects of the Toxic Metalloid Tellurite (TeO₃²⁻) on the Plasma Membrane Redox System of the Facultative PhototrophRhodobacter capsulatus