A copper‐induced quinone degradation pathway provides protection against combined copper/quinone stress in <scp><i>L</i></scp><i>actococcus lactis</i> <scp>IL</scp>1403

Mancini, Stefano; Abicht, Helge K.; Gonskikh, Yulia; Solioz, Marc

doi:10.1111/mmi.12889

Cited by 17 publications

(12 citation statements)

References 59 publications

(111 reference statements)

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“…Both toxicity mechanisms, however, are independent of ROS production. The lack of oxidative damage under copper stress has been documented for L. lactis (42). Copper reduced the metabolic heat flow at any phase of culture growth and delayed the attainment of maximal metabolic activity.…”

Section: Discussionmentioning

confidence: 99%

Mechanism of Attenuation of Uranyl Toxicity by Glutathione in Lactococcus lactis

Obeid

Oertel

Solioz

et al. 2016

Appl Environ Microbiol

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b ABSTRACTBoth prokaryotic and eukaryotic organisms possess mechanisms for the detoxification of heavy metals, and these mechanisms are found among distantly related species. We investigated the role of intracellular glutathione (GSH), which, in a large number of taxa, plays a role in protection against the toxicity of common heavy metals. Anaerobically grown Lactococcus lactis containing an inducible GSH synthesis pathway was used as a model organism. Its physiological condition allowed study of putative GSH-dependent uranyl detoxification mechanisms without interference from additional reactive oxygen species. By microcalorimetric measurements of metabolic heat during cultivation, it was shown that intracellular GSH attenuates the toxicity of uranium at a concentration in the range of 10 to 150 M. In this concentration range, no effect was observed with copper, which was used as a reference for redox metal toxicity. At higher copper concentrations, GSH aggravated metal toxicity. Isothermal titration calorimetry revealed the endothermic binding of U(VI) to the carboxyl group(s) of GSH rather than to the reducing thiol group involved in copper interactions. The data indicate that the primary detoxifying mechanism is the intracellular sequestration of carboxyl-coordinated U(VI) into an insoluble complex with GSH. The opposite effects on uranyl and on copper toxicity can be related to the difference in coordination chemistry of the respective metal-GSH complexes, which cause distinct growth phase-specific effects on enzyme-metal interactions. IMPORTANCEUnderstanding microbial metal resistance is of particular importance for bioremediation, where microorganisms are employed for the removal of heavy metals from the environment. This strategy is increasingly being considered for uranium. However, little is known about the molecular mechanisms of uranyl detoxification. Existing studies of different taxa show little systematics but hint at a role of glutathione (GSH). Previous work could not unequivocally demonstrate a GSH function in decreasing the presumed uranyl-induced oxidative stress, nor could a redox-independent detoxifying action of GSH be identified. Combining metabolic calorimetry with cell number-based assays and genetics analysis enables a novel and general approach to quantify toxicity and relate it to molecular mechanisms. The results show that GSH-expressing microorganisms appear advantageous for uranyl bioremediation.T he natural abundance of uranium and the increasing health risks that originate from its anthropogenic release to the environment have generated a high demand for understanding the molecular mechanisms of uranium toxicity. Its radiotoxicity is of minor ecological relevance compared to its toxicity due to chemical interference with metabolism (1, 2). The latter is caused mostly by the displacement of Ca 2ϩ and Mg 2ϩ from functionally important binding sites in enzymes (3). The water-soluble uranyl cation UO 2 2ϩ is the most commonly found contaminant, which contains uranium in its highest ...

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Section: Discussionmentioning

confidence: 99%

Mechanism of Attenuation of Uranyl Toxicity by Glutathione in Lactococcus lactis

Obeid

Oertel

Solioz

et al. 2016

Appl Environ Microbiol

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“…Furthermore, resistance against copper is most often dependent upon efflux mechanism. Mancini et al (2015) reported that P-type ATPases detoxify copper via efflux mechanism in some species. However, it has been reported that copper metabolism occurs naturally in all living organisms, and is generally chromosomally encoded (Ahemad 2012).…”

Section: Determination Of the Mic Of Heavy Metals And Antibiotic Resimentioning

confidence: 99%

“…These results show that the accumulation amount of metal ions by the Micrococcus strain is relatively stable for the three heavy metals and are relatively far from ours. Beside that, some studies reported that bacteria are able to accumulate and compartmentalize copper in the cell's periplasm and the outer membrane and concluded the protective mechanism against copper due to productions of four proteins to overcome copper stress (Cooksey 1994;Mancini et al 2015). Adebisi Musbaudeen et al (2014) reported that Micrococcus luteus is not only resistant against copper and nickel, but also had the extensive capability of accumulating these heavy metals.…”

Section: Accumulation Of Metal Ions By Living Bacterial Cellsmentioning

confidence: 99%

Isolation and characterization of metal-resistant bacterial strain from wastewater and evaluation of its capacity in metal-ions removal using living and dry bacterial cells

Benmalek

Fardeau

2016

Int. J. Environ. Sci. Technol.

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A novel strain of the genus Micrococcus isolated from wastewater was studied for resistance to seven heavy metals and forty antibiotics. Its capacity to accumulate metal ions was also realized at different pH. The strain exhibited high minimal inhibitory concentration values for metal ions tested and resist to 15 antibiotics. The living cells of the bacterial strain show a largest uptake capacity at pH 6-8.5 for copper, nickel, and zinc with values ranging from 51.45 to 83.90 %, 52.59 to 78.81 %, and 59.55 to 78.90 %, respectively. It was also able to absorbed 59.81-80.08 % of chromium and 58.09-79.41 % of cobalt at pH 7.3-8.5. The maximum lead uptake was obtained at pH 5.5-8.5 with an amount of 55.28-91.06 %. The significant absorption of cadmium was shown at pH 6.5 with 38 %. In 25 lg mL-1 zinc, chromium, and nickel solutions, dead cells of the isolate were able to biosorbed 20.46, 22.5, and 23.98 lg mL -1 , respectively, after 30 min of contact. In other solutions with higher concentrations 50 and 100 lg mL -1 , the amount of each metal immobilized was, respectively, as follows: 38.02 and 90.21 lg mL -1 for zinc, 39.78 and 89.23 lg mL -1 for chromium, and 47.19 and 86.83 lg mL -1 for nickel. Due to its high-metal accumulation capacity in aerobic conditions, these Grampositive bacteria may be potentially applicable in situ bioremediation of heavy metals contaminating aqueous systems.

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“…The experiment was performed at 25 °C in a 5 mL chamber containing 4 mL of 100 mM PBS at pH 8.0, 0.4 mL substrate (2,6-DTBP), and 0.4 mL crude protein extract. 36,37 …”

Section: Methodsmentioning

confidence: 99%

A comprehensive study of conditions of the biodegradation of a plastic additive 2,6-di-tert-butylphenol and proteomic changes in the degraderPseudomonas aeruginosasan ai

et al. 2019

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The Pseudomonas aeruginosa san ai strain was investigated for its capability to degrade the 2,6-di-tertbutylphenol (2,6-DTBP) plastic additive, a hazardous and toxic substance for aquatic life. This investigation was performed under different parameter values: 2,6-DTBP concentration, inoculum size, pH, and temperature. The GC-MS study showed that P. aeruginosa efficiently degraded 2,6-DTBP in the pH range of 5-8 at higher temperatures. Under exposure to 2,6-DTBP concentrations of 2, 10, and 100 mg L À1 , the strain degraded by 100, 100, and 85%, respectively, for 7 days. Crude enzyme preparation from the biomass of P. aeruginosa san ai showed higher efficiency in 2,6-DTBP removal than that shown by whole microbial cells. Gene encoding for the enzymes involved in the degradation of aromatic compounds in P. aeruginosa san ai was identified. To complement the genomic data, a comparative proteomic study of P. aeruginosa san ai grown on 2,6-DTBP or sunflower oil was conducted by means of nanoLC-MS/MS. The presence of aromatic substances resulted in the upregulation of aromatic ring cleavage enzymes, whose activity was confirmed by enzymatic tests; therefore, it could be concluded that 2,6-DTBP might be degraded by ortho-ring cleavage. A comparative proteomics study of P. aeruginosa san ai indicated that the core molecular responses to aromatic substances can be summarized as the upregulation of proteins responsible for amino acid metabolism with emphasized glutamate metabolism and energy production with upregulated enzymes of glyoxylate bypass. P. aeruginosa san ai has a high capacity to efficiently degrade aromatic compounds, and therefore its whole cells or enzymes could be used in the treatment of contaminated areas.

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A copper‐induced quinone degradation pathway provides protection against combined copper/quinone stress in Lactococcus lactis IL1403

Cited by 17 publications

References 59 publications

Mechanism of Attenuation of Uranyl Toxicity by Glutathione in Lactococcus lactis

Mechanism of Attenuation of Uranyl Toxicity by Glutathione in Lactococcus lactis

Isolation and characterization of metal-resistant bacterial strain from wastewater and evaluation of its capacity in metal-ions removal using living and dry bacterial cells

A comprehensive study of conditions of the biodegradation of a plastic additive 2,6-di-tert-butylphenol and proteomic changes in the degraderPseudomonas aeruginosasan ai

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