The Te-Assay: A black and white method for environmental sample pre-screening exploiting tellurite reduction

Lloyd‐Jones, Gareth; Williamson, William Crawford; Slootweg, Tineke

doi:10.1016/j.mimet.2006.05.006

Cited by 7 publications

(4 citation statements)

References 14 publications

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“…The commonly used cytotoxicity screening assays are mostly based on fluorescence or absorbance measurements following toxicant exposure and incubation with a colorimetric indicator dyes but has many limitations with nanotoxicity assessment [25], [26], [27], [28].Thus, Wang et al [29] developed a novel bioluminescence inhibition assay exploiting Photobacterium phosphoreum to evaluate the toxicity of quantum dots. Also, a black and white method (Te-assay) for pre-screening of environmental samples based on reduction of tellurite (TeO 3 2 − ) to elemental tellurium has been reported [30]. Along the similar principle, we have attempted to exploit the selenite tolerant Pseudomonas aeruginosa strain JS-11 isolated from wheat rhizosphere for biosynthesis of Se-NPs and utilized its capacity of reducing of SeO 3 2 − to Se 0 , as a metabolic marker for visual assessment of the relative toxicity of several NPs in a single experiment in a 96-well format.…”

Section: Introductionmentioning

confidence: 99%

Biomimetic Synthesis of Selenium Nanospheres by Bacterial Strain JS-11 and Its Role as a Biosensor for Nanotoxicity Assessment: A Novel Se-Bioassay

et al. 2013

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Selenium nanoparticles (Se-NPs) were synthesized by green technology using the bacterial isolate Pseudomonas aeruginosa strain JS-11. The bacteria exhibited significant tolerance to selenite (SeO3 2−) up to 100 mM concentration with an EC50 value of 140 mM. The spent medium (culture supernatant) contains the potential of reducing soluble and colorless SeO3 2− to insoluble red elemental selenium (Se0) at 37°C. Characterization of red Se° product by use of UV-Vis spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM) with energy dispersive X-ray spectrum (EDX) analysis revealed the presence of stable, predominantly monodispersed and spherical selenium nanoparticles (Se-NPs) of an average size of 21 nm. Most likely, the metabolite phenazine-1-carboxylic acid (PCA) released by strain JS-11 in culture supernatant along with the known redox agents like NADH and NADH dependent reductases are responsible for biomimetic reduction of SeO3 2− to Se° nanospheres. Based on the bioreduction of a colorless solution of SeO3 2− to elemental red Se0, a high throughput colorimetric bioassay (Se-Assay) was developed for parallel detection and quantification of nanoparticles (NPs) cytotoxicity in a 96 well format. Thus, it has been concluded that the reducing power of the culture supernatant of strain JS-11 could be effectively exploited for developing a simple and environmental friendly method of Se-NPs synthesis. The results elucidated that the red colored Se° nanospheres may serve as a biosensor for nanotoxicity assessment, contemplating the inhibition of SeO3 2− bioreduction process in NPs treated bacterial cell culture supernatant, as a toxicity end point.

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Section: Introductionmentioning

confidence: 99%

Biomimetic Synthesis of Selenium Nanospheres by Bacterial Strain JS-11 and Its Role as a Biosensor for Nanotoxicity Assessment: A Novel Se-Bioassay

et al. 2013

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“…An intriguing twist is that Te(IV) is reduced by living cells to volatile methylated forms such as dimethyltellurium or to elemental tellurium, Te(0) (21,24,52). In bacteria, the latter is typically deposited as black aggregates with strain-specific nanostructures resulting in a distinct darkening of cells and tissues (30,55), a phenomenon that is exploitable in environmental viability screens (31).…”

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confidence: 99%

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

et al. 2010

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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.

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“…strain WAY isolated from wastewater reduced the Te(IV) forming elemental tellurium as black colonies exhibited the potentiality for the green synthesis of tellurium nanorods [ 64 ]. Previous studies have reported the isolation of tellurite-reducing bacteria that produce TeNPs from various natural habitats [ 65 , 66 , 67 , 68 ].…”

Section: Discussionmentioning

confidence: 99%

Biosynthesis of Novel Tellurium Nanorods by Gayadomonas sp. TNPM15 Isolated from Mangrove Sediments and Assessment of Their Impact on Spore Germination and Ultrastructure of Phytopathogenic Fungi

et al. 2023

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The biosynthesis of nanoparticles using green technology is emerging as a cost-efficient, eco-friendly and risk-free strategy in nanotechnology. Recently, tellurium nanoparticles (TeNPs) have attracted growing attention due to their unique properties in biomedicine, electronics, and other industrial applications. The current investigation addresses the green synthesis of TeNPs using a newly isolated mangrove-associated bacterium, Gayadomonas sp. TNPM15, and their impact on the phytopathogenic fungi Fusarium oxysporum and Alternaria alternata. The biogenic TeNPs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FTIR). The results of TEM revealed the intracellular biosynthesis of rod-shaped nanostructures with a diameter range from 15 to 23 nm and different lengths reaching up to 243 nm. Furthermore, the successful formation of tellurium nanorods was verified by SEM-EDX, and the XRD pattern revealed their crystallinity. In addition, the FTIR spectrum provided evidence for the presence of proteinaceous capping agents. The bioinspired TeNPs exhibited obvious inhibitory effect on the spores of both investigated phytopathogens accomplished with prominent ultrastructure alternations, as evidenced by TEM observations. The biogenic TeNPs impeded spore germination of F. oxysporum and A. alternata completely at 48.1 and 27.6 µg/mL, respectively. Furthermore, an increase in DNA and protein leakage was observed upon exposure of fungal spores to the biogenic TeNPs, indicating the disruption of membrane permeability and integrity. Besides their potent influence on fungal spores, the biogenic TeNPs demonstrated remarkable inhibitory effects on the production of various plant cell wall-degrading enzymes. Moreover, the cytotoxicity investigations revealed the biocompatibility of the as-prepared biogenic TeNPs and their low toxicity against the human skin fibroblast (HSF) cell line. The biogenic TeNPs showed no significant cytotoxic effect towards HSF cells at concentrations up to 80 μg/mL, with a half-maximal inhibitory concentration (IC50) value of 125 μg/mL. The present work spotlights the antifungal potential of the biogenic TeNPs produced by marine bacterium against phytopathogenic fungi as a promising candidate to combat fungal infections.

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The Te-Assay: A black and white method for environmental sample pre-screening exploiting tellurite reduction

Cited by 7 publications

References 14 publications

Biomimetic Synthesis of Selenium Nanospheres by Bacterial Strain JS-11 and Its Role as a Biosensor for Nanotoxicity Assessment: A Novel Se-Bioassay

Biomimetic Synthesis of Selenium Nanospheres by Bacterial Strain JS-11 and Its Role as a Biosensor for Nanotoxicity Assessment: A Novel Se-Bioassay

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

Biosynthesis of Novel Tellurium Nanorods by Gayadomonas sp. TNPM15 Isolated from Mangrove Sediments and Assessment of Their Impact on Spore Germination and Ultrastructure of Phytopathogenic Fungi

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