scholarly journals Derivation of pb(II)-sensing Escherichia coli cell-based biosensors from arsenic responsive genetic systems

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yejin Lee ◽  
Yangwon Jeon ◽  
Guepil Jang ◽  
Youngdae Yoon
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ion ◽  
Genetic System ◽  
Regulatory Proteins ◽  
Divalent Metal Ions ◽  
Genes Encoding ◽  
P Type ◽  
Arsenic Sensing

AbstractHeavy metal-responsive operons were used for the generation of Escherichia coli cell-based biosensors. The selectivity and specificity of the biosensors were determined based on the interaction between heavy metals and regulatory proteins; thereby, the modulating target selectivity of biosensors could be achieved by changing target sensing properties of regulatory proteins. The results of this study demonstrated that Pb(II)-sensing biosensors could be generated from an arsenic-responsive genetic system, which was originally used for arsenic-sensing biosensors. The amino acids around to As(III)-binding sites of ArsR were mutated and cysteine residues were relocated to modulate the metal selectivity. In addition, genes encoding metal ion-translocating P-type ATPases, such as copA and zntA, were deleted to enhance the specificity by increasing the intercellular levels of divalent metal ions. Based on the results, channel protein deleted E. coli cells harboring a pair of recombinant genes, engineered ArsR and arsAp::egfp, showed enhanced responses upon Pb exposure and could be used to quantify the amount of Pb(II) in artificially contaminated water and plants grown in media containing Pb(II). Although we focused on generating Pb(II)-specific biosensors in this study, the proposed strategy has a great potential for the generation of diverse heavy metal-sensing biosensors and risk assessment of heavy metals in environmental samples as well as in plants.

scholarly journals Draft Genome Sequence of the Novel Enterobacter cloacae Strain amazonensis, a Highly Heavy Metal-Resistant Bacterium from a Contaminated Stream in Amazonas, Brazil

2018 ◽  
Vol 6 (22) ◽  
Author(s):  
Maria Clara Tavares Astolfi ◽  
Elen Bethleen de Souza Carvalho ◽  
Adriane Menezes de Barros ◽  
Marcelo Valente Pinto ◽  
Luna Barrôco de Lacerda ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Draft Genome ◽  
Enterobacter Cloacae ◽  
The Novel ◽  
Biotechnological Applications ◽  
Toxic Compounds ◽  
Content Type ◽  
Genes Encoding ◽  
Heavy Metal Resistant

ABSTRACT Here, we report the draft genome of the Enterobacter cloacae strain amazonensis, a bacterium highly resistant to mercury that was isolated from a metal- and sewage-contaminated stream in Amazonas, Brazil. The exploration of the 5.0-Mb genome revealed 104 genes encoding resistance to toxic compounds and heavy metals, highlighting the potential biotechnological applications of this strain.

Detection of heavy metal toxicity and genotoxicity in wastewaters by microbial assay

1994 ◽  
Vol 30 (10) ◽  
pp. 145-151 ◽  
Author(s):  
J. C. Codina ◽  
A. Pérez-García ◽  
A. de Vicente
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Toxicity ◽  
Ames Test ◽  
Deionized Water ◽  
Toxicity Tests ◽  
Water Solutions ◽  
Microbial Assay ◽  
Higher Sensitivity

The effect of wastewater on the sensitivity of toxicity and genotoxicity assays for the detection of heavy metals was evaluated. Five microbiological toxicity tests were used to compare the toxicity of cadmium, copper, chromium, mercury, nickel, and zinc, both in deionized water solutions and in wastewater. The toxicity assays employed were: Microtox®, two tests of growth inhibition using Pseudomonas fluorescens, and two spectrophotometric assays of the inhibition of respiration test using baker's yeast and P. fluorescens. Also, the genotoxic effect of the assayed metals was evaluated by using the Ames test, the Escherichia coli WP2 test, and the SOS test. The sensitivity to metals decreases in most of the toxicity and genotoxicity assays; in general, higher sensitivity thresholds (EC20) in wastewater than in water solutions were determined. Each test shows different sensitivities to each metal, which is related to different sensitivities of the organisms used in the assays, as well as to other factors.

scholarly journals Plant-Based Tacca leontopetaloides Biopolymer Flocculant (TBPF) Produced High Removal of Heavy Metal Ions at Low Dosage

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 37
Author(s):  
Nurul Shuhada Mohd Makhtar ◽  
Juferi Idris ◽  
Mohibah Musa ◽  
Yoshito Andou ◽  
Ku Halim Ku Hamid ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Metal Removal ◽  
Test Procedure ◽  
Synthetic Wastewater ◽  
Leachate Treatment ◽  
Low Concentration ◽  
Removal Of Heavy Metals

High removal of heavy metals using plant-based bioflocculant under low concentration is required due to its low cost, abundant source, and nontoxicity for improved wastewater management and utilization in the water industry. This paper presents a treatment of synthetic wastewater using plant-based Tacca leontopetaloides biopolymer flocculant (TBPF) without modification on its structural polymer chains. It produced a high removal of heavy metals (Zn, Pb, Ni, and Cd) at a low concentration of TBPF dosage. In our previous report, TBPF was characterized and successfully reduced the turbidity, total suspended solids, and color for leachate treatment; however, its effectiveness for heavy metal removal has not been reported. The removal of these heavy metals was performed using a standard jar test procedure at different pH values of synthetic wastewater and TBPF dosages. The effects of hydroxide ion, pH, initial TBPF concentration, initial metal ion concentration, and TBPF dosage were examined using one factorial at the time (OFAT). The results show that the highest removal for Zn, Pb, Ni, and Cd metal ions were 98.4–98.5%, 79–80%, 97–98%, and 92–93%, respectively, using 120 mg/L dosage from the initial concentration of 10% TBPF at pH 10. The final concentrations for Zn, Pb, Ni, and Cd metal ions were 0.043–0.044, 0.41–0.43, 0.037–0.054, and 0.11–0.13 mg/L, respectively, which are below the Standard B discharge limit set by the Department of Environment (DOE), Malaysia. The results show that TBPF has a high potential for the removal of heavy metals, particularly Zn, Pb, Ni, and Cd, in real wastewater treatment.

Migration Patterns of Heavy Metals in Soil in Wastewater Irrigation Area in the Suburb of Eastern Inner Mongolia

2011 ◽  
Vol 343-344 ◽  
pp. 340-343
Author(s):  
Ri Cha Hu ◽  
Li Bo Sun
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Inner Mongolia ◽  
Metal Ion ◽  
Vertical Direction ◽  
Heavy Metal Concentration ◽  
Water Shortage ◽  
Wastewater Irrigation ◽  
Irrigation Area ◽  
Eastern Inner Mongolia

Based on the soil test of heavy metals in wastewater irrigation area in eastern Inner Mongolia, this paper analyses the content of heavy metals Cr, Cu, Cd, Pb in different layers of soil samples and reveals the internal relations between heavy metal concentration gradient in the vertical direction and soil properties, thus providing a scientific basis to guide sewage irrigation, solve the problem of water shortage in wastewater irrigation area and carry out environmental impact assessment. Soil is an important subsystem in natural environmental systems, through which many pollutants, especially heavy metals, produced by human activities, enter the food chain and ultimately do harm to human health. Currently, heavy metal ion contamination to the soil caused by wastewater irrigation has become one of the focuses in the study of soil chemistry and agricultural environment pollution. For this reason, it is particularly important to study the migration mechanism of heavy metals in soil and to provide a reliable theoretical basis for the prevention and management of soil contaminants.

scholarly journals pH-Regulated Carbon Dots Fluorescence Sensor Array Detection of Multiple Heavy Metal Ions Under Stepwise Prediction

2022 ◽  
Author(s):  
Zijun Xu ◽  
Yuying Liu ◽  
Jiao Chen ◽  
Xiyuan Wang ◽  
Hao Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Sensor Array ◽  
Chelating Agent ◽  
Fluorescence Sensor ◽  
Array Detection ◽  
Multiple Heavy Metals

Abstract As a large amount of heavy metals leaches into water sources from industrial effluents, heavy metal pollution has become an important factor affecting water quality. To enable the detection of multiple heavy metals, we constructed a pH-regulation fluorescence sensor array. Firstly, by adding a metal chelating agent as receptor, metal ions and carbon quantum dots (CDs) were connected to distinguish between Cr6+, Fe3+, Fe2+, and Hg2+ ions. Thus, the lack of affinity between the indicator functional groups and the analyte was solved. Secondly, by adjusting the pH environment of the solution system, an economical and simple array sensing platform is established, which effectively simplified the array construction. In this study, the SX-model was used in the field of fluorescence sensor array detection for metal ion recognition. Based on the strategy of stepwise prediction, combined with the classification and concentration models, the bottleneck of the unified model in previous studies was broken. This sensor array demonstrated sensitive detection of four heavy metal ions within a concentration range from 1 to 50 µM, with an accuracy of 95.45%. Moreover, it displayed the ability to efficiently identify binary mixed samples with an accuracy of 95.45%. Furthermore, metal ions in 15 real samples (lake water) were effectively discriminated with 100% accuracy. A chelating agent was used to improve the sensitivity of heavy metal ion detection and eventually led to high-precision prediction using the SX-model.

Sorption of Heavy Metal on Natural Clay

2018 ◽  
Vol 68 (12) ◽  
pp. 2804-2807
Author(s):  
Mircea Stefan ◽  
Adriana Bors ◽  
Daniela Simina Stefan ◽  
Ionut Alexandru Savu Radu ◽  
Cicerone Marinescu
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ion ◽  
Background Electrolyte ◽  
Hydroxyl Groups ◽  
Natural Clay ◽  
Equilibrium Isotherms ◽  
Solution Ph ◽  
Constant Ph ◽  
Langmuir Isotherm Model

Sorption of heavy metals on Na-montmorillonite was studied as a function of solution pH and different concentrations of background electrolyte and also a function of added metal ion at constant pH. Equilibrium isotherms have been measured and analyzed using a Langmuir isotherm model. The metal ions were predominantly adsorbed on the permanent charge sites in a easily replaceable state. There was also evident a substantial involvement of the hydroxyl groups on the edges of Na-montmorillonite in specific adsorption of the cations especially at higher pH.

scholarly journals Biosorption and Bioaccumulation Abilities of Actinomycetes/Streptomycetes Isolated from Metal Contaminated Sites

Separations ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 54 ◽  
Author(s):  
Ivana Timková ◽  
Jana Sedláková-Kaduková ◽  
Peter Pristaš
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ion ◽  
Polluted Soil ◽  
Negative Effects ◽  
Wide Range ◽  
Specific Uptake ◽  
High Concentrations ◽  
Further Development ◽  
Soil And Water

Heavy metal pollution is of great concern. Due to expansion of industrial activities, a large amount of metal is released into the environment, disturbing its fragile balance. Conventional methods of remediation of heavy metal-polluted soil and water are expensive and inefficient. Therefore, new techniques are needed to provide environmentally friendly and highly selective remediation. Streptomycetes, with their unique growth characteristics, ability to form spores and mycelia, and relatively rapid colonization of substrates, act as suitable agents for bioremediation of metals and organic compounds in polluted soil and water. A variety of mechanisms could be involved in reduction of metals in the environment, e.g., sorption to exopolymers, precipitation, biosorption and bioaccumulation. Studies performed on biosorption and bioaccumulation potential of streptomycetes could be used as a basis for further development in this field. Streptomycetes are of interest because of their ability to survive in environments contaminated by metals through the production of a wide range of metal ion chelators, such as siderophores, which provide protection from the negative effects of heavy metals or specific uptake for specialized metabolic processes. Many strains also have the equally important characteristic of resistance to high concentrations of heavy metals.

scholarly journals Spatial Relationships Between pH and Vegetation Pattern in an Area Contaminated with Heavy Metals

2003 ◽  
pp. 140-143
Author(s):  
Elza Kovács ◽  
János Tamás
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Plant Species ◽  
Metal Ion ◽  
Toxic Elements ◽  
Vegetation Pattern ◽  
Ion Concentration ◽  
Vegetation Density ◽  
Highly Sensitive ◽  
Ph Conditions

It is not possible to gain information on the risk factor representing the bioavailability and the mobility of the contaminants only on the basis of their total concentrations. Especially, in case of heavy metals, which can be charaterised with very different chemical forms and their mobil and mobilizable parts are determined by complex balances highly sensitive to the changing environmental conditions. Considering mine tailings, however, the toxic elements are basically in ore forms having low adsorption capacity, thus the heavy metal ion concentration in solution is governed mainly by the pH conditions. In Gyöngyösoroszi, the spatial distribution of the total heavy metal concentrations as well as that of pH values determining the bioavailable part of the toxic elements were estimated and by mapping the vegetation pattern, relationship was analysed among the total Zn, Cu, Pb and As concentrations, the pH and the species present. Results show that the presence of the certain plant species is highly determined by the pH on the mine tailing material, the highest vegetation density was found where the bioavailability of the toxic elements were considered the smallest as a result of the neutral pH. As a result, high diversity could be found even in places where the total zinc, copper, lead and arsenic concentrations were extreme. In addition, plant species could be identified, which are tolerant to toxic elements and present even if the pH is low and the bioavailable part of the heavy metals is relatively high.

scholarly journals Comparative study of binding strengths of heavy metals with humic acid

2013 ◽  
Vol 67 (5) ◽  
pp. 773-779 ◽  
Author(s):  
Ivana Kostic ◽  
Tatjana Andjelkovic ◽  
Ruzica Nikolic ◽  
Tatjana Cvetkovic ◽  
Dusica Pavlovic ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Humic Acid ◽  
Metal Ions ◽  
Stability Constants ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Exchange Method ◽  
Divalent Metal Ion ◽  
The Stability

The complexation of humic acid with certain heavy metal ions (Co(II), Ni(II), Cu(II), Zn(II) and Pb(II)) was investigated. The stability constants of humate complexes were determined by method which is based on distribution of metal ions between solution and resin in the presence and the absence of ligand, known as Schubert?s ion exchange method. Experiments were performed at 25 ?C, at pH 4.0 and ionic strength of 0.01 mol dm-3. It was found that the 1:1 complexes were formed between metal ions and humic acid. Obtained results of the stability constants, log ?mn, of complexes formed between the metal ions and humic acid follow the order Co(II) < Ni(II) < Cu(II) > Zn(II) which is the same like in the Irving-Williams series for the binding strength of divalent metal ion complexes. Stability constant of complex between Pb(II) ions and humic acid is greater than stability constants of other investigated metal-humate complexes. The investigation of interaction between heavy metal ions and humics is important for the prediction of the distribution and control of the migration of heavy metals in natural environment.

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