Enhancement of UV and chromate mutagenesis by nickel ions in the Chinese hamster HGPRT Assay †

1. The HGPRT (Hypoxanthine‐Guanine‐Phospho‐Ribosyl‐Transferase) assay with Chinese Hamster V79 cells was used to measure the mutagenic effects of UV irradiation, potassium dichromate and nickel chloride. The agents were tested separately and in the combinations of UV plus nickel and dichromate plus nickel.

2. UV, Cr(VI) and Ni(II) were confirmed to be mutagenic in the V79 cell assay. The combination of UV(5J/m²) and Ni(II) (0.5 mM) caused a mutation rate 11.2 times above that corresponding to the sum of the individual mutation rates of these agents. The combined action of Cr(VI) (0.1 mM) and Ni(II) (0.5 mM) produced a mutation rate 2.8 fold above that corresponding to the sum of the individual rates of the separate agents.

3. The enhancing effect of nickel chloride on the mutagenicity of UV or Cr(VI) is interpreted by an interference of Ni(II) with the repair of DNA lesions.     

Recovery of Ni(II) from real electroplating wastewater using fixed-bed resin adsorption and subsequent electrodeposition

Resin adsorption and subsequent electrodeposition were used for nickel recovery. Treated wastewater can meet the Electroplating Pollutant Discharge Standard. The spent resin is completely regenerated by 3 BV of 4% HCl solution. 95.6% of nickel in concentrated eluent was recovered by electrodeposition. Effective recovery of high-value heavy metals from electroplating wastewater is of great significance, but recovering nickel ions from real electroplating wastewater as nickel sheet has not been reported. In this study, the pilot-scale fixed-bed resin adsorption was conducted to recover Ni(II) ions from real nickel plating wastewater, and then the concentrated Ni(II) ions in the regenerated solution were reduced to nickel sheet via electrodeposition. A commercial cation-exchange resin was selected and the optimal resin adsorption and regeneration conditions were investigated. The resin exhibited an adsorption capacity of 63 mg/g for Ni(II) ions, and the average amount of treated water was 84.6 bed volumes (BV) in the pilot-scale experiments. After the adsorption by two ion-exchange resin columns in series and one chelating resin column, the concentrations of Ni(II) in the treated wastewater were below 0.1 mg/L. After the regeneration of the spent resin using 3 BV of 4% (w/w) HCl solution, 1.5 BV of concentrated neutral nickel solution (>30 g/L) was obtained and used in the subsequent electrodeposition process. Using the aeration method, alkali and water required in resin activation process were greatly reduced to 2 BV and 3 BV, respectively. Under the optimal electrodeposition conditions, 95.6% of Ni(II) in desorption eluent could be recovered as the elemental nickel on the cathode. The total treatment cost for the resin adsorption and regeneration as well as the electrodeposition was calculated.     

Uptake and genotoxicity of micromolar concentrations of cobalt chloride in mammalian cells

Literature data concerning the genotoxicity of cobalt salts have been conflicting. To establish appropriate incubation conditions, we conducted a series of uptake studies, before genotoxicity was determined by DNA strand break induction in HeLa cells and mutagenicity in V79 Chinese hamster cells. Co(II) is taken up by HeLa cells in a concentration‐dependent manner and is accumulated inside the cell. The uptake is preceded by a fast association step to the outer membrane, with no saturation up to 24 h. DNA strand breaks as determined by nucleoid sedimentation are induced at concentrations as low as 50μMCoCl₂. The induction is time‐dependent, showing the highest number of breaks after 4h incubation with no further increase up to 24h. CoCl₂ is mutagenic at the HPRT‐locus, enhancing the spontaneous mutation frequency 4.2‐fold at 100μ?. Besides direct interactions with DNA, the mutagenicity of CoCl₂ could also be due to a decrease in the Fidelity of DNA polymerisation.     

The influence of sorption material preparation on the removal of metal ions from the aqueous solution

ABSTRACT

Very important in adsorption processes is the preparation of material sorbents and from this reason, the impact of washing agent of raw sorbent was analysed. The adsorption capacity was studied in relation to the function of the equilibrium time, the amount of biosorbent and the initial metal(II) ions concentration. In this research for the sake of comparison, the sorptive properties of out-of-date coffee were compared to coffee washed with different agents (mineral acids and water). The scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterise the biosorbents and to identify the functional groups that participated in metal(II) ions bonding. The obtained results clearly indicate that the out-of-date coffee are effective biosorbent for cadmium(II) and nickel(II) ions from aqueous solution. However, for metal(II) ions removal efficiency could influence sorbent preparation and nickel(II) ions were best adsorbed on coffee washed with water, but cadmium(II) ions on raw biosorbent (out-of-date coffee). The best results of sorption were achieved after the contact time of 30 and 60?min, respectively for cadmium(II) and nickel(II) ions.     

Biochemical speciation in chromium genotoxicity

The biochemical speciation of chromium compounds in mammalian cells is discussed with respect to uptake, metabolism, DNA binding and damaging. Whereas soluble hexavalent chromium is taken up rapidly and accumulated intracellularly after its reduction, compounds of trivalent chromium penetrate biomembranes about three orders of magnitude slower. Cr(VI) after its uptake is metabolised by electron donating compounds via Cr(V) to Cr(III) compounds. Chromium from various Cr(III) compounds, but not chromate, binds to chromatin in isolated cell nuclei. The DNA‐protein crosslinks and DNA strand breaks observed in rat liver and kidney after chromate administration are also found in vitro, when Cr(III) compounds (but not chromate) interacts with isolated nuclei. In the Chinese Hamster cell HGPRT mutation assay, three out of four tested Cr(III) complexes were found to be mutagenic. In a direct DNA strand break assay with supercoiled bacteriophage PM 2 DNA, neither chromate nor the four Cr(III) compounds tested caused nicks. However, the combined action of chromate plus glutathione as well as the isolated complex of pentavalent chromium, Na₄Cr(glutathione)₄, did cause DNA breaks. Reactive oxygen species are inferred to be the ultimate DNA nicking agents in this assay. In conclusion there appear to be two mechanisms of chromate genotoxicity; one with direct DNA damage caused by Cr(V) species and one via DNA‐protein crosslinks formed with Cr(III), the final reduction state of chromate.     

羰基镍急性中毒对大鼠骨髓细胞的DNA损伤

通过动物实验观察不同剂量羰基镍对大鼠骨髓细胞DNA损伤程度。采用SD大鼠,以135 mg·m~(-3)和250 mg·m~(-3)羰基镍为染毒组,250 mg·m~(-3)氯气为阳性对照组,静态方式染毒30 min。未染毒组为正常对照组,大鼠染毒后1、2、3和7 d分别采集样本。采用单细胞凝胶电泳检测每组大鼠骨髓细胞DNA的损伤程度。彗星尾长和Olive尾矩2个指标的分析结果表明,大鼠骨髓细胞DNA损伤程度随着羰基镍染毒剂量的增加而增加,在4个时间点各剂量组间均有显著差异(P0.05)且随时间的变化有一定的规律,损伤程度在3 d时达到最大,而后缓慢下降。羰基镍急性中毒对大鼠骨髓细胞DNA有一定的损伤,且存在剂量-效应关系,各剂量组损伤程度有一定的时间效应规律。     

Cadmium and nickel determinations in some food and water samples by the combination of carrier element-free coprecipitation and flame atomic absorption spectrometry

A procedure for separation and enrichment of Cd(II) and Ni(II) ions based upon carrier element-free coprecipitation by using an organic coprecipitant, 2-{4-[2-(1H-Indol-3-yl)ethyl]-3-(4-methylbenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}-N′-(3-fluoro-phenylmethyliden) acetohydrazide, prior to their flame atomic absorption spectrometric detections has been developed. The effects of varied experimental conditions on the performance of the developed method such as pH, sample volume, amount of coprecipitating agent, etc. were evaluated in detail on the recovery of analyte ions, and the influences of some anions and cations were investigated. The limits of detection for Cd(II) and Ni(II) ions based on three times the standard deviation of the blanks (N: 10) were obtained as 0.70 μg L^?1 and 1.21 μg L^?1, respectively. The accuracy of the method was tested by analyzing a certified reference material and by spike tests. The method was applied to determine the levels of cadmium and nickel in stream and sea water, rice, red lentil, and wheat samples.     

Determination trace amounts of copper, nickel, cobalt and manganese ions in water samples after simultaneous separation and preconcentration

In the present article, a simple, rapid, sensitive and economical method has been developed for the simultaneous separation and preconcentration of the trace amounts of copper, nickel, cobalt and manganese in water samples by using modified XAD-4 resins. The sorption was quantitative in the pH range 6.0–9.0, whereas quantitative desorption occurred instantaneously with 5.0 mL of 2 M HNO₃, and selected elements have been determined by using flame atomic absorption spectrometry. Dynamic ranges were 0.04–3.5, 0.1–6.0, 0.04–4.5 and 0.04–4.0 μg/mL for copper, nickel, cobalt and manganese, respectively. The detection limits were 9.2, 28.6, 12.3 and 5.7 ng/mL for Cu(II), Ni(II), Co(II) and Mn(II), respectively. The effects of the experimental parameters, including the sample pH, eluent type, interference ions and breakthrough volume, were studied for separation and preconcentration of Cu(II), Ni(II), Co(II) and Mn(II) ions. Determination of these ions in standard samples confirmed that the proposed method has good accuracy. The proposed method was used for the determination of these ions in water samples.     

Biosorption of cadmium and nickel ions using marine macrophyte,Cymodocea nodosa

ABSTRACT

Seagrass (Cymodocea nodosa) ability to remove cadmium and nickel ions from single metal solutions was investigated in the present study. Metal ions were measured in the solution using an atomic absorption spectrophotometer. Various operational parameters (initial pH, biomass dose, metal ion concentration, and contact time) were tested and found to affect the uptake capacity of Cd (II) and Ni (II). More than 70% of biosorption capacity occurred in the first few minutes for both metal ions. The pseudo-second-order kinetic model and the Langmuir model were found to best fit the experimental data of Cd (II) and Ni (II) biosorption. The maximum uptake capacity (q_max) was 11.6 and 16.7?mg.g^?1 for Cd (II) and Ni (II), respectively. The biosorbent was characterised using Fourier transform infrared spectrometry (FTIR), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). The infrared spectrum demonstrated that hydroxyl, carboxyl, and phenolic functional groups are the major binding sites for Cd (II) and Ni (II) metals. The ion exchange mechanism plays an important role during biosorption process as shown in EDX analysis. Our results conclude that marine macrophyte C. nodosa can be used as a low-cost biosorbent for the removal of Cd (II) and Ni (II) in wastewater.     

The cytotoxicity of nici2 for mammalian cells in culture†

The effects of NiCl₂ were studied in two human cell lines, HeLa and diploid embryonic fibroblasts as well as in V79 Chinese hamster cells and in L‐A mouse fibroblasts. NiCl₂ produces a dose‐dependent depression of proliferation, mitotic rate, and viability, accompanied by an increasing release of lactic dehydrogenase and stimulation of lactic acid production. The plating efficiency is reduced, as are DNA and protein synthesis and, to a lesser degree, RNA synthesis.

The cytotoxicity of NiCl₂ is comparable in degree to those of PbCl₂ and MnCl₂, but is weaker than those of HgCl₂ and CdCl₂. However, the different sensitivities of different cell lines must also be considered.

NiCl₂ effects are more severe in serum‐free medium than in medium containing serum or serum albumin indicating that serum constituents, notably albumin, bind the metal effectively and inhibit cellular uptake; this confirms earlier reports on the serum binding and slow uptake of NiCl₂.

Synchronized cells are most sensitive in the Gl and early S phases of the cell cycle. In the Painter test the depression of DNA synthesis persists following cessation of exposure to NiCI₂. These findings contribute an explanation for the known genotoxic effects of nickel.     

用于核酸损伤和化合物基因毒性检测的新型DNA电化学传感器

利用电化学方法检测DNA损伤和污染物基因毒性具有重要意义．根据分子膜层层自组装的原理,将受化学损伤的小牛胸腺DNA固定于氧化铟锡电极表面,制备出核酸传感器界面．使用DNA嵌入剂二联吡啶二吡啶并[3,2- a;2’,3’-c]吩嗪钌[Ru(bpy)2dppz2+]作为电信号指示剂,与核酸膜结合后,进行电化学检测．由于嵌入剂具有很高的DNA结合能力和双链特异性,与DNA的结合数量在损伤前后发生变化．在电化学检测中,采用已研究成功的高倍数信号放大机制,用电子给予体草酸还原Ru(bpy)2dppz3+,使之循环产生电流信号．这样,嵌入剂与DNA结合数目的微量变化得到灵敏检测．在工作中,分别采用石英晶体微天平和电化学方法对DNA的表面固定进行了表征,计算出未损伤DNA的固定量为3．2 ng·mm-2,损伤DNA的固定量为4．2 ng·mm-2．对两种核酸膜进行电化学检测,发现在信号放大剂草酸溶液中,损伤DNA的电流信号显著高于未损伤DNA,前者是后者的2．2倍．通过荧光分析,得到Ru(bpy)2 dppz2+与损伤DNA的结合常数(K=1．07×107 M-1)和结合比(0．68)．嵌入剂与损伤DNA结合物的荧光强度是未损伤DNA 的1．5倍,说明损伤后嵌入剂结合量增加了1．5倍．损伤DNA电化学检测信号增高的主要原因是由于信号指示剂嵌入电极表面核酸数量的增加．利用高结合能力、高选择性的电化学嵌入剂,结合高倍数信号放大机制,可以对核酸损伤进行灵敏检测．     

Humic substances. Part III. sorptive interactions with environmental chemicals†

The formation of covalent binding to DNA of a carcinogen is now widely accepted to represent a classical mechanism of tumour induction in mammals. This mechanism does not operate with metals since no covalent binding of these agents to DNA does occur. Nevertheless, somatic mutations as typical consequences of DNA‐damage have been reported to be induced by metals in various model systems. Beside DNA‐alkylation such damages can be caused by changes in the conformation of DNA or in the fidelity of DNA‐repair. The activity of the repair enzymes DNA‐polymerases is indeed impaired by many metal ions at least in vitro. It is not yet established whether these mechanisms are also important in the intact mammalian organism. Much evidence has accumulated during the last years that a disturbance of the balance of cations and especially metal ions represents another possible mechanism of tumour induction. The tumours found with high doses of chelating agents such as nitrilo‐triacetic acid (NTA) have to be discussed in this context. Since most—if not—all of the speculative mechanisms of metal carcinogenesis resemble classical pharmacological reactions the existence of a threshold level is likely. So metal carcinogenesis will not be a problem of the environmental contamination at trace levels but a problem of occupational medicine.     

Nanosilica exerts cytotoxicity and apoptotic response via oxidative stress in mouse embryonic fibroblasts

Nanoscale silica is an important industrial material and extensively used in medicines. The objective of this study was to determine potential cytotoxicity and genotoxic effects attributed to nanosilica exposure in mouse embryonic fibroblasts (L929) cells. Nanosilica produced mild cytotoxicity in L929 cells. Results showed that nanosilica increased thiobarbituric acid reactive substance levels and enhanced superoxide dismutase activity but decreased levels of glutathione. This was accompanied by a concomitant generation of reactive oxygen species, loss of mitochondrial membrane potential, and activation of caspase-3 activity. In addition, in the single-cell gel test, nanosilica (50–300 μg/ml) at two treatment times 24 and 48 hr produced concentration- and time-dependent increase of DNA damage. Therefore, the obtained results indicate that nanosilica may induce genotoxic effects in cultured L929 cells associated with induction of oxidative stress.     

Amberlite XAD-7 impregnated with morpholine dithiocarbamate as trace metal extractant

Application of Amberlite XAD-7 impregnated with morpholine dithiocarbamate (MDTC) for separation and preconcentration of trace amounts of lead, copper, cobalt, iron, nickel, cadmium and zinc and determination by ICP-AES has been described. The optimum experimental parameters, such as pH, sample flow rate, eluent and effect of matrix ions on the preconcentration were investigated. Simultaneous enrichment of the seven metals was accomplished. The t _1/2 values for sorption are 2.9, 3.3, 3.7, 3.6, 2.8, 4.1 and 2.8 respectively for Pb(II), Cu(II), Co(II), Fe(III), Ni(II), Cd(II) and Zn(II). The method was applied for the determination of trace metal ions in seawater and natural water samples. The results have been compared with extraction GFAAS method.     

Cytogenetic and epigenetic alterations by cobalt and nickel on Zea mays L

Changes in DNA methylation in Zea mays plantlets in response to cobalt and nickel (5, 10, 20, and 40 mmol L^?1) evaluated by the coupled restriction enzyme digestion-random amplification technique revealed dose-related increases in hypermethylation. The effects on mitotic index and phytohormone levels were also determined. Co and Ni caused a decrease in mitotic index and an attenuation in the growth-promoting hormones gibberellic acid, zeatin, and indole acetic acid, while abscisic acid levels rose. These findings have shown that the increase in abscisic acid levels and DNA methylation depend on the concentrations of Co and Ni.     

Oxidisability of environmental sulphur under different catalytic conditions

The oxidation of elemental sulphur in the catalytic presence of selected metal ions [Cr(III), Ce(III), Cu(II), Hg(II), Ni(II), Co(II), Mo(VI), Cd(II), Zn(II), Ti(IV), and V(V)], and hydrocarbons (benzene, gasoline, and kerosene) was studied in an alkaline medium buffered by marble powder. The catalytic efficiencies of metal ions were: Cr(III) > Ce(III) > Cu(II) > Hg(II) > Ni(II). The oxidation process was inhibited in the presence of other ions, and the inhibitive effect was in the following order: Co(II) < Mo(VI) < Cd(II) < Zn(II) < Ti(IV) < V(V). In the case of hydrocarbons, the efficiencies were as follows: gasoline > benzene > kerosene. The oxidation of sulphur in sulphur-loaded soils obtained from near a textile mill and a distillery were also carried out in the c both cases was significantly enhanced.To whom all correspondence should be addressed.     

Degradation of Ni–EDTA complex by Fenton reaction and ultrasonic treatment for the removal of Ni<Superscript>2+</Superscript> ions

It is difficult to meet the increasingly stringent environmental regulations by the application of conventional precipitation processes treating complex heavy metal wastewaters. We studied the potential of a new method for removing heavy metals from metal–EDTA wastewater by Fenton reaction followed by hydroxide precipitation. This process is referred to as Fenton reaction-hydroxide precipitation (FR-HP) process. This study investigated the use of FR-HP and ultrasonic/FR-HP processes for the removal of Ni(II) from Ni–EDTA wastewater. The results indicate that ultrasonic/FR-HP process is more effective for the removal of nickel ions than FR-HP process.     

二氧化锰颗粒对Hela细胞DNA损伤的尺度依赖性毒作用(英文)

为了观察二氧化锰颗粒物所致的尺度依赖性DNA损伤作用,将纳米尺度二氧化锰颗粒物(Nano-MnO2)和常规尺度二氧化锰颗粒物(Nor-MnO2)所致的DNA损伤进行了对比研究.将Hela细胞分别暴露于不同浓度(0、100、200、400μg·mL-1)的Nano-MnO2和Nor-MnO2中,染毒24h,采用彗星实验检测Hela细胞的DNA损伤水平.结果表明:与对照组相比,Nano-MnO2和Nor-MnO2均可使彗尾DNA百分比(TailDNA%)和尾矩(TailMoment)显著增加(p<0.01);而在同一浓度水平上,Nano-MnO2所致的DNA损伤则比Nor-MnO2所致的DNA损伤更为严重(p<0.01).结果提示:二氧化锰颗粒对Hela细胞DNA损伤具有尺度依赖性毒作用,纳米尺度比常规尺度二氧化锰颗粒毒作用更强烈.     

Mutagenic activity of transition‐metal complexes: Relation structure‐mutagenic and antibacterial activity for some Pd(II), Pt(II) and Rh(I) complexes†

The inhibitory and mutagenic action of some Pd(II), Pt(II) and Rh(I) complexes towards various bacterial strains has been evaluated, and some correlations have been found between the chemical behaviour of the complexes and their selective biological activity: most of the complexes cause only a DNA damage repaired by the excision repair system. Particularly, the Rh(I) complexes used in this work show selective antibacterial effects on defective but no effect on wild‐type strains.