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1.
A highly selective colorimetric and long‐wavelength fluorescent probe for the detection of Hg2+
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Jing Xu Zuokai Wang Caiyun Liu Zhenghe Xu Ning Wang Xin Cong Baocun Zhu 《Luminescence》2018,33(6):1122-1127
Currently, the fluorescent probe is an important method for detecting heavy metal ions, especially mercury ion (Hg2+), which is harmful to the health of humans and the environment due to its toxicity and extensive use. In this paper, we designed and synthesized a colorimetric and long‐wavelength fluorescent probe Hg‐P with high sensitivity and excellent selectivity, which could detect Hg2+ by the changes of visual color, fluorescence and absorption spectroscopy. With the addition of Hg2+ to probe Hg‐P solution, its color changed from yellow to pink, and showed a 171 nm red‐shifted absorption spectrum. Probe Hg‐P was used in real water and soil solution samples to detect Hg2+, and the result is satisfactory. Therefore, this new probe shows great value and application in detecting Hg2+ in the environment. 相似文献
2.
A carbonothioate‐based highly selective fluorescent probe with a large Stokes shift for detection of Hg2+
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Jing Xu Zhenghe Xu Zuokai Wang Caiyun Liu Baocun Zhu Xiuru Wang Kun Wang Jiangting Wang Guoqing Sang 《Luminescence》2018,33(1):219-224
Mercury (Hg) is one of the heavy metal pollutants in the environment. Even a very small amount of mercury can cause serious harm to human beings. Herein, we reported a new carbonothioate‐based fluorescent probe for the detection of Hg2+ without interference from other metal ions. This probe possessed a very large Stokes shift (192 nm), which could improve the detection sensitivity by minimizing the interferences resulted from self‐absorption or auto‐fluorescence. With the addition of Hg2+ to the probe solution, considerable fluorescence enhancement was observed. Additionally, the Hg2+ concentration of 0–16 μM and fluorescence intensity showed a good linear relationship (y = 22106× + 53108, R2 = 0.9955). Finally, the proposed probe was used to detect Hg2+ in real water samples, and its result was satisfactory. Therefore, our proposed probe would provide a promising method for the determination of Hg2+ in the environment. 相似文献
3.
Minimal inhibitory concentration values of HgCl2 and 5 organomercurials were determined against 24 mercury-resistant N2-fixing soil bacteria previously isolated from soil and identified in our laboratory. These bacterial strains also displayed
multiple antibiotic resistant properties. Typical growth pattern of a highly mercury-resistantBeijerinckia sp (KDr2) was studied in liquid broth supplemented with toxic levels of mercury compounds. Four bacterial strains were selected for
determining their ability to volatilize mercury and their Hg-volatilizing capacity was different. Cell-free extracts prepared
from overnight mercury-induced cells catalyzed Hg2+-induced NADPH oxidation. Specific activities of Hg2+-reductase which is capable of catalyzing conversion of Hg2+ →Hg(o) of 10 Hg-resistant bacterial strains are also reported. 相似文献
4.
In order to study phenotypic and genotypic alterations in response to selected conditions of stress, Pseudomonas aeruginosa PU21, harboring the multi-resistance plasmid, Rip64 (142.5 kb), was adapted by serial subcultivation on selective agar plates, amended with either Hg2+, carbenicillin, or gentamicin. Concentrations of the selective agents, to which P. aeruginosa PU21 Rip64 carried plasmid-encoded resistance genes, were close to or slightly above the respective minimal inhibitory concentration. Three different substrains were obtained: R64-M was adapted to Hg2+, R64-C to carbenicillin, and R64-G to geneamicin. All three substrains showed elevated levels of Hg2+ and carbenicillin resistance. Resistance to other antibiotics was either increased, decreased or unaffected. Increased Hg2+ resistance in all adapted substrains was accompanied by higher activity and less stringent induction of mercury reductase, as determined by Hg-volatilization assays with resting cells. No plasmid alterations compared to the non-adapted strain were detected in R64-C, but in R64-M and R64-G plasmid sizes increased by approx. 23 kb, as detected by pulsed field gel electrophoresis and the occurrence of additional DNA fragments after digestions with several restriction endonucleases. The plasmid localized gene rearrangements were accompanied by additional DNA fragments hybridizing with a merA gene probe. 相似文献
5.
6.
Takeshi Nagata Hirofumi Morita Toshifumi Akizawa Hidemitsu Pan-Hou 《Applied microbiology and biotechnology》2010,87(2):781-786
To develop the potential of plant for phytoremediation of methylmercury pollution, a genetically engineered tobacco plant
that coexpresses organomercurial lyase (MerB) with the ppk-specified polyphosphate (polyP) and merT-encoding mercury transporter was constructed by integrating a bacterial merB gene into ppk/merT-transgenic tobacco. A large number of independent transgenic tobaccos was obtained, in some of which the merB gene was stably integrated in the plant genome and substantially translated to the expected MerB enzyme in the transgenic
tobacco. The ppk/merT/merB-transgenic tobacco callus showed more resistance to methylmercury (CH3Hg+) and accumulated more mercury from CH3Hg+-containing medium than the ppk/merT-transgenic and wild-type progenitors. These results suggest that the MerB enzyme encoded by merB degraded the incorporated CH3Hg+ to Hg2+, which then accumulated as a less toxic Hg-polyP complex in the tobacco cells. Phytoremediation of CH3Hg+ and Hg2+ in the environment with this engineered ppk/merT/merB-transgenic plant, which prevents the release mercury vapor (Hg0) into the atmosphere in addition to generating potentially recyclable mercury-rich plant residues, is believed to be more
acceptable to the public than other competing technologies, including phytovolatilization. 相似文献
7.
K. Pahan D. K. Ghosh J. Chaudhuri R. Gachhui S. Ray A. Mandal 《Journal of biosciences》1995,20(1):83-88
Bacillus pasteurii DR2, a broad-spectrum Hg-resistant bacterial strain, exhibited delayed sporulation and less mercury volatilization in the presence
of mercury compounds. However, Hg-sensitiveBacillus subtilis sporulated quickly in the presence of HgCl2 and volatilized no mercury. Levels of Hg2+-reductase and organomercurial lyase in the endospores ofBacillus pasteurii DR2 were lower than those in vegetative cells 相似文献
8.
A novel 2,4-dichlorophenol hydroxylase (TfdB, EC 1.14.13.20) gene, designated as tfdB-JLU, was identified from a metagenome constructed from polychlorinated biphenyl-contaminated soil by functional screening and
heterologously expressed in Escherichia coli. The deduced amino acid sequence of tfdB-JLU exhibited less than 48% homology with other known TfdBs. The enzyme exhibited a wider substrate spectrum than the previously
reported TfdBs and higher relative activity towards ortho-substituted dichlorophenols, 2-chlorophenol, and 3-chlorophenol
than towards 2,4-dichlorophenol, the preferred substrate of other known TfdBs. The enzyme had a K
m
of 5 μM for 2,4-dichlorophenol and 6 μM for NADPH. The optimal temperature and pH of the enzyme were 25°C and 7.5, respectively.
Activity of the purified TfdB-JLU was slightly enhanced by Ca2+, Mn2+, Co2+, and Fe2+, and completely inhibited by Cu2+, Hg2+, and Zn2+. This study is the first report to identify a novel TfdB from a metagenome. 相似文献
9.
The influence of mercury ions (Hg2+, 10 μM) on photosynthesis was investigated in flagellates and aplanospores of Haematococcus lacustris. Hg2+ stress resulted in a fast decrease of chlorophyll fluorescence yield. This was initially caused by an increase in reversible non-photochemical quenching of chlorophyll fluorescence. During further exposure to Hg2+, an increasing contribution of pH independent non-photochemical quenching and a parallel rise in the content of the xanthophyll cycle pigment zeaxanthin was detected. An increase of the initial chlorophyll fluorescence as a final sign of Hg2+ induced adverse effects on photosynthesis supports our hypothesis that mercury ions predispose to non-reversible, “chronic” photoinhibition. 相似文献
10.
A hexavalent chromium [Cr(VI)] reducing bacterial strain was isolated from chromium-containing slag. It was identified as
Pannonibacter phragmitetus based on physiological, biochemical characteristics and 16S rRNA gene sequence analysis. This bacterium displayed great Cr(VI)
reduction capability. The Cr(VI) could be completely removed in 24 h under anaerobic condition when the initial concentration
was 1,917 mg L−1, with the maximum reduction rate of 562.8 mg L−1 h−1. The Cr(VI) reduction rate increased with the increase of Cr(VI) concentration. P. phragmitetus was able to use many carbon sources such as lactose, fructose, glucose, pyruvate, citrate, formate, lactate, NADPH and NADH
as electron donors, among which the lactate had the greatest power to promote the reduction process. Zn2+, Cd2+ and Ni2+ inhibited, while Cu2+, Pb2+, Mn2+ and Co2+ stimulated the reduction. The optimum pH and temperature for reduction were 9.0 and 30 °C, respectively. The results indicated
that this strain had great potential for application in the bioremediation of chromate-polluted soil and water systems. 相似文献
11.
Na'il Saleh 《Luminescence》2009,24(1):30-34
A water‐soluble, high‐output fluorescent sensor, based on a lumazine ligand with a thiophene substituent for Cd2+, Hg2+ and Ag+ metal ions, is reported. The sensor displays fluorescence enhancement upon Cd2+ binding (log β = 2.79 ± 0.08) and fluorescence quenching by chelating with Ag+ and Hg2+ (log β = 4.31 ± 0.15 and 5.42 ± 0.1, respectively). The mechanism of quenching is static and occurs by formation of a ground‐state non‐fluorescent complex followed by rapid intersystem crossing. The value of the Stern–Volmer quenching rate constant (kq) by Ag+ ions is close to 6.71 × 1012 mol/L/s at 298 K. The thermodynamic parameters (ΔG, ΔH and ΔS) were also evaluated and indicated that the complexation process is spontaneous, exothermic and entropically favourable. The quantitative linear relationship between the softness values of Klopman (σK) or Ahrland (σA) and the experimental binding constants (β) being in the order of Hg2+ > Ag+ > Cd2+ suggests that soft–soft interactions are the key for the observed sensitivity and selectivity in the presence of other metal ions, such as: Pb2+, Ni2+, Mn2+, Cu2+, Co2+, Zn2+ and Mg2+ ions. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
12.
A simple naphthalimide-based fluorescent probe was designed and synthesized for the determination of mercury ion (Hg2+). The probe showed a noticeable fluorescence quenching response for Hg2+. When added with Hg2+, the fluorescence intensity of the probe at 560 nm was remarkably decreased with the color changed from yellow to colorless under ultraviolet (UV) light. The probe had a notable selectivity and sensitivity for Hg2+ and displayed an excellent sensing performance when detecting Hg2+ at low concentration (19.5 nM). The binding phenomenon between the probe and Hg2+ was identified by Job's method and high-resolution mass spectrometry (HRMS). Moreover, the probe was not only utilized to identify Hg2+ in real samples with satisfactory results (92.00%–110.00%) but also was successfully used for bioimaging in cells and zebrafish. The recognition mechanism has been verified by transmission electron microscopy (TEM) for the first time. All the results showed that the probe could be used as a potent useful tool for detection of Hg2+. 相似文献
13.
Karunasagar D. Arunachalam J. Rashmi K. Naveena Lavanya Latha J. Maruthi Mohan P. 《World journal of microbiology & biotechnology》2003,19(3):291-295
A biosorbent prepared by alkaline extraction of Aspergillus niger biomass was evaluated for its potential to remove mercury species – inorganic (Hg2+) and methyl mercury (CH3Hg+) – from aqueous solutions. Batch experiments were carried out to determine the pH and time profile of sorption for both species in the pH range 2–7. The Hg2+ exhibited more rapid sorption and higher capacity than the CH3Hg+. Further, removal of both mercury species from spiked ground water samples was efficient and not influenced by other ions. Sorption studies with esterified biosorbent indicated loss of binding of both mercury species (>80%), which was regained when the ester groups were removed by alkaline hydrolysis, suggesting the involvement of carboxyl groups in binding. Further, no interconversion of sorbed species occurred on the biomass. The biosorbent was reusable up to six cycles without serious loss of binding capacity. Our results suggest that the biosorbent from Aspergillus niger can be used for removal of mercury and methyl mercury ions from polluted aqueous effluents. 相似文献
14.
Qinguo Wei Jiakuo Yan Yao Chen Lei Zhang Xiaoyang Wu Shuai Shang Shisheng Ma Tian Xia Shuyu Xue Honghai Zhang 《Molecular biotechnology》2018,60(1):12-20
The metalloregulatory protein MerR which plays important roles in mer operon system exhibits high affinity and selectivity toward mercury (II) (Hg2+). In order to improve the adsorption ability of Saccharomyces cerevisiae for Hg2+, MerR was displayed on the surface of S. cerevisiae for the first time with an α-agglutinin-based display system in this study. The merR gene was synthesized after being optimized and added restriction endonuclease sites EcoR I and Mlu I. The display of MerR was indirectly confirmed by the enhanced adsorption ability of S. cerevisiae for Hg2+ and colony PCR. The hydride generation atomic absorption spectrometry was applied to measure the Hg2+ content in water. The engineered yeast strain not only showed higher tolerance to Hg, but also their adsorption ability was much higher than that of origin and control strains. The engineered yeast could adsorb Hg2+ under a wide range of pH levels, and it could also adsorb Hg2+ effectively with Cd2+ and Cu2+ coexistence. Furthermore, the engineered yeast strain could adsorb ultra-trace Hg2+ effectively. The results above showed that the surface-engineered yeast strain could adsorb Hg2+ under complex environmental conditions and could be used for the biosorption and bioremediation of environmental Hg contaminants. 相似文献
15.
To develop the potential of plants to sequester and accumulate mercurials from the contaminated sites, we engineered a tobacco (Nicotiana tabacum) plant to express a bacterial ppk gene, encoding polyphosphate kinase (PPK), under control of a plant promoter. The designated plant expression plasmid pPKT116 that contains the entire coding region of ppk was used for Agrobacterium-mediated gene transfer into tobacco plants. A large number of independent transgenic tobacco plants were obtained, in some of which the ppk gene was stably integrated in the plant genome and substantially translated to the expected PPK protein in the transgenic tobacco. The presence of Hg2+ did not cause considerable morphological abnormalities in the transgenic tobacco, which grew, flowered, and set seed similarly to the wild-type tobacco on the medium containing normally toxic levels of Hg2+. The ppk-transgenic tobacco showed more resistance to Hg2+ and accumulated more mercury than its wild-type progenitors. These results suggest that ppk-specified polyphosphate has abilities to reduce mercury toxicity, probably via chelation mechanism, and also to accumulate mercury in the transgenic tobacco. Based on the results obtained in the present study, the expression of ppk gene in transgenic tobacco plants might provide a means for phytoremediation of mercury pollution. 相似文献
16.
《Bioscience, biotechnology, and biochemistry》2013,77(6):1494-1499
Overexpression of a mercuric ion binding protein, MerP, from the mercury resistance operon genes of Gram-positive bacterial strain Bacillus megaterium MB1 and from Gram-negative bacterial strain Pseudomonas aeruginosa K-62 was found to enhance the mercury resistance level of Escherichia coli host cells, even though they share only 27.3% identity. Immunoblot analysis showed that MerP (BMerP) from Bacillus could be expressed on the membrane fraction of E. coli cells. Treated with 10 μM Hg2+, a recombinant strain harboring the BMerP gene significantly improved, showing a 27% increase in mercuric ion adsorption capacity, 16% better than that of a Pseudomonas merP gene (PMerP)-harboring strain. While multiple heavy metals co-existed, the mercuric ion adsorption capacity of the BMerP-harboring E. coli was not affected while that of the PMerP-harboring strain decreased. These results suggest that BMerP can act as a bio-adsorbent compartmentalizing the toxic mercuric ion on the cell membrane and enhancing resistance. 相似文献
17.
Bo-Kyung Kim Bo-Hwa Lee Yoo-Jung Lee Il-Hyuck Jin Chung-Han Chung Jin-Woo Lee 《Enzyme and microbial technology》2009,44(6-7):411-416
The microorganism hydrolyzing carboxymethylcellulose (CMC) was isolated from seawater, identified as Bacillus subtilis subsp. subtilis by analyses of 16S rDNA and partial sequences of the gyrA gene, and named as B. subtilis subsp. subtilis A-53. The molecular weight of the purified carboxymethylcellulase (CMCase) was estimated to be about 56 kDa with the analysis of SDS-PAGE. The purified CMCase hydrolyzed carboxymethylcellulose (CMC), cellobiose, filter paper, and xylan, but not avicel, cellulose, and p-nitrophenyl-β-d-glucospyranoside (PNPG). Optimal temperature and pH for the CMCase activity were determined to be 50 °C and 6.5, respectively. More than 70% of original CMCase activity was maintained at relative low temperatures ranging from 20 to 40 °C after 24 h incubation at 50 °C. The CMCase activity was enhanced by EDTA and some metal ions in order of EDTA, K+, Ni2+, Sr2+, Pb2+, and Mn2+, but inhibited by Co2+ and Hg2+. 相似文献
18.
Huang CC Chen MW Hsieh JL Lin WH Chen PC Chien LF 《Applied microbiology and biotechnology》2006,72(1):197-205
A eukaryotic microalga, Chlorella sp. DT, was transformed with the Bacillus megaterium strain MB1 merA gene, encoding mercuric reductase (MerA), which mediates the reduction of Hg2+ to volatile elemental Hg0. The transformed Chlorella cells were selected first by hygromycin B and then by HgCl2. The existence of merA gene in the genomic DNA of transgenic strains was shown by polymerase chain reaction amplification, while the stable integration of merA into genomic DNA of transgenic strains was confirmed by Southern blot analysis. The ability to remove Hg2+ in merA transgenic strains was higher than that in the wild type. The merA transgenic strains showed higher growth rate and photosynthetic activity than the wild type did in the presence of a toxic concentration of Hg2+. Cultured with Hg2+, the expression level of superoxide dismutase in transgenic strains was lower than that in the wild type, suggesting that the transgenic strains faced a lower level of oxidative stress. All the results indicated that merA gene was successfully integrated into the genome of transgenic strains and functionally expressed to promote the removal of Hg2+. 相似文献
19.
The purpose of the present study was to investigate the in vitro and the in vivo effects of cadmium, zinc, mercury and lead on -aminolevulinic acid dehydratase (ALA-D) activity from radish leaves. The in vivo effect of these metals on growth, DNA and protein content was also evaluated. The results demonstrated that among the elements studied Cd2+ presented the highest toxicity for radish. 50% inhibition of ALA-D activity (IC50) in vitro was at 0.39, 2.39, 2.29, and 1.38 mM Cd2+, Zn2+, Hg2+ and Pb2+, respectively. After in vivo exposure Cd2+, Zn2+, Hg2+ and Pb2+ inhibited ALA-D by about 40, 26, 34 and 15%, respectively. Growth was inhibited by about 40, 10, 25, and 5% by Cd2+, Zn2+, Hg2+, and Pb2+, respectively. DNA content was reduced about 35, 30, 20, and 10% for Cd2+, Zn2+, Hg2+, and Pb2+, respectively. The metal concentration in radish leaves exposed to Cd2+, Zn2+, Hg2+, and Pb2+ was 18, 13, 6, and 7 mol g–1, respectively. The marked ability of radish to accumulate Cd2+ and Zn2+ raises the possibility of using this vegetable as a biomonitor of environmental contamination by these metals. 相似文献
20.
John Gutknecht 《The Journal of membrane biology》1981,61(1):61-66
Summary Diffusion of inorganic mercury (Hg2+) through planar lipid bilayer membranes was studied as a function of chloride concentration and pH. Membranes were made from egg lecithin plus cholesterol in tetradecane. Tracer (203Hg) flux and conductance measurements were used to estimate the permeabilities to ionic and nonionic forms of Hg. At pH 7.0 and [Cl–] ranging from 10–1000mm, only the dichloride complex of mercury (HgCl2) crosses the membrane at a significant rate. However, several other Hg complexes (HgOHCl, HgCl
3
–
and HgCl
4
2–
) contribute to diffusion through the aqueous unstirred layer adjacent to the membrane. The relation between the total mercury flux (J
Hg), Hg concentrations, and permeabilities is: 1/J
Hg=1/P
ul[Hg
t
]+1/P
m
[HgCl2], where [Hg
t
] is the total concentration of all forms of Hg,P
ul is the unstirred layer permeability, andP
m
is the membrane permeability to HgCl2. By fitting this equation to the data we find thatP
m
=1.3×10–2 cm sec–1. At Cl– concentrations ranging from 1–100mm, diffusion of Hg
t
through the unstirred layer is rate limiting. At Cl– concentrations ranging from 500–1000mm, the membrane permeability to HgCl2 becomes rate limiting because HgCl2 comprises only about 1% of the total Hg. Under all conditions, chemical reactions among Hg2+, Cl– and/or OH– near the membrane surface play an important role in the transport process. Other important metals, e.g., Zn2+, Cd2+, Ag+ and CH3Hg+, form neutral chloride complexes under physiological conditions. Thus, it is likely that chloride can facilitate the diffusion of a variety of metals through lipid bilayer and biological membranes. 相似文献