Biosorption of lead and nickel by living and non-living cells of Pseudomonas aeruginosa ASU 6a

The optimum conditions for biosorption and bioaccumulation of lead and nickel were investigated by using a tolerant bacterial strain isolated from El-Malah canal, Assiut, Egypt, and identified as Pseudomonas aeruginosa ASU 6a. The experimental adsorption data were fitted towards the models postulated by Langmuir and Freundlich isotherm equations. The binding capacity by living cells is significantly lower than that of dead cells. The maximum biosorption capacities for lead and nickel obtained by using non-living cells and living cells were 123, 113.6 and 79, 70 mg/g, respectively. The biosorptive mechanism was confirmed by IR analysis and from the identification nature of acidic and basic sites. Moreover, the postulated mechanism was found to depend mainly on ionic interaction and complex formation.     

Effects of mine effluent on uptake of Co,Ni, Cu,As, Zn,Cd, Cr and Pb by aquatic macrophytes

Concentrations of Ni, Co, Cu, Pb, Zn, Cd, Cr and As were determined in aquatic sediments, water and macrophytes collected from a fluvial system, contaminated by mine effluents. Myriophyllum verticillatum collected in May below the trace element point source accumulated 169 µg/g of Ni, 860 µg/g of Co, 37 µg/g of Cu, 31 µg/g of Pb, 92 µg/g of Zn, 6.9 µg/g of Cr and 1,200 µg/g of As (concentrations in dry weight). The aquatic macrophytes Nymphaea odoratae and Pontederia cordata accumulated the investigated trace elements to a much lesser extent. The concentrations of trace elements in Myriophyllum verticillatum decreased from May to August. Correlations were found between the concentrations of total Ni, Co and Cu in the bottom sediment and in the submerged macrophytes. However, there was no correlation between the amounts of these trace elements extractable by 0.5 N HCl from the sediments and the concentrations in the macrophytes.     

Development of a bioassay from isolated digestive gland cells of the cuttlefish Sepia officinalis L. (Mollusca Cephalopoda): effect of Cu, Zn and Ag on enzyme activities and cell viability

The purpose of this study was to establish a bioassay from isolated digestive gland cells of the cuttlefish Sepia officinalis in order to observe the effect of heavy metals on digestive enzyme activities. Digestive cells were isolated using a pronase enzyme that was removed by several washings of the cell suspension. Cell viability was tested by the MTT assay (3-4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium) and microscopic analysis. The results showed that isolated digestive cells could be maintained 24 h with preservation of whole digestive functionality, measured in terms of MTT test. In fact, the viability was maintained at a high level during 24 h and the intra- and extracellular digestive enzyme activities became stabilised rapidly. Furthermore, suspension cells responded to calcium ionophore and 8-Bromo-cAMP by an unspecific secretion of extracellular digestive enzyme, trypsin, which demonstrated that isolated digestive cells were functional. Using the bioassay, ecotoxicological studies showed that heavy metals could have effects on digestive enzyme activities after 24 h of an incubation time of the metal with the cells. In fact, zinc and silver affected trypsin and/or cathepsins specific activity of the cells. On the contrary, copper had no effect on digestive enzyme activities. Zinc, which is a trace element in all living animals, generated two different responses of cathepsins and cell viability. At a low concentration (0.02 μM), it increased viability and cathepsins specific activity, whereas at a high concentration (0.02 mM), zinc inhibited the cathepsins specific activity with an inhibition of cathepsins. For silver, whatever the tested concentration (0.02 mM or 0.02 μM), it has no impact on digestive gland isolated cell viability. Nevertheless, heavy metal induced high disturbance of enzymatic systems.     

The Combined Effect of Cu,Zn and Pb on Enzyme Activities in Soil from the Vicinity of a Wellhead Protection Area

Heavy metals are known to have adverse effects on soil ecosystems, while soil enzyme activities are sensitive to soil pollution. This study investigated the combined effects of Cu, Zn and Pb on the activities of invertase (IN), urease (U) and alkaline phosphatase (ALP) in soil obtained from the vicinity of a wellhead protection area via an orthogonal array (OA) design method. The experimental results showed the following: (1) Cu showed higher inhibition on the activities of all three enzymes than Zn and Pb when three metals were all present in the soil sample. IN activity, U activity and ALP activity decreased as the levels of Cu increased, and ranged from 15.9% to 55.7%, 3.57% to 78.6%, and 3.23% to 75.3%, respectively. Their lowest values were found in samples at 35 days with 400 mg/kg Cu. (2) Zn and Pb had different influences on the activities of the three enzymes. The lowest IN activity (the highest reduction 58.0%) and U activity (76.8%) were observed when Zn was at the concentration of 100 mg/kg after 35 days, whereas the highest inhibitory function of Zn on ALP activity (75.3%) was at 300 mg/kg after 7 days. When the concentration of Pb increased from 35 to 350 mg/kg, the activities of IN (62.5%) and U (69.6%) were most inhibited at 35 days and 14 days, respectively. However, when Pb was at the concentration of 500 mg/kg after 14 days, ALP activity (72.0%) showed the lowest value. (3) With respect to the three hydrolases in this study, ALP was the most sensitive to the two-variable interactive effects of Cu, Zn and Pb, especially Cu?×?Pb. It is concluded that the soil ALP activity may be a sensitive tool for assessing additive toxic effect on soil biochemical parameters. To provide more information about the potential ecological risk of chemicals on soil ecosystems, much more should be done to clearly determine the mechanisms of the combined effects of heavy metals in soil.     

Phytoaccumulation of zinc by the aquatic plant, Lemna gibba L.

The uptake of zinc (Zn) by the duckweed Lemna gibba L., native to the north-east region of Algeria, was investigated in quarter Coïc solutions enriched with 6.0, 10.0, 14.0 and 18.0 mg l⁻¹ of Zn supplied as zinc sulphate (ZnSO₄). Zinc concentrations were measured in the water daily and in duckweed biomass at the end of the experiments. These results showed that under experimental conditions (pH = 6.0 ± 0.1, T = 21 ± 1 °C, photoperiod = 12 h/j), L. gibba was able to accumulate in its biomass 4.23; 15.62; 23.88 and 25.81 mg g⁻¹ DM, respectively for the four initial concentrations selected. At these concentrations, the metal removed percentages were 61–71%. The mass balance performed on the system showed that about 49–68% of Zn (depending on the initial concentration in water) was removed by precipitation as zinc phosphate. The results showed that this aquatic plant can be successfully used for Zn removal.     

Sorption of Cu(II) and Cd(II) by extracellular polymeric substances (EPS) from Aspergillus fumigatus

Sorption of Cu(II) and Cd(II) onto the extracellular polymeric substances (EPS) produced by Aspergillus fumigatus was investigated for the initial pH of the solution, EPS concentrations, contact time, NaCl concentration, initial metal ion concentration and the presence of other ions in the solution. The results showed that the adsorption of metal ions was significantly affected by pH, EPS concentrations, initial metal concentration, NaCl concentration and co-ions. The sorption of Cu(II) and Cd(II) increased with increasing pH and initial metal ion concentration but decreased with an increase in the NaCl concentration. The maximum sorption capacities of A. fumigatus EPS calculated from the Langmuir model were 40 mg g⁻¹ EPS and 85.5 mg g⁻¹ EPS for Cu(II) and Cd(II), respectively. The binary metal sorption experiments showed a selective metal binding affinity in the order of Cu(II) > Pb(II) > Cd(II). Both the Freundlich and Langmuir adsorption models described the sorption of Cu(II) and Cd(II) by the EPS of A. fumigatus adequately. Fourier transform infrared spectroscopy (FTIR) analysis revealed that carboxyl, amide and hydroxyl functional groups were mainly correlated with the sorption of Cu(II) and Cd(II). Energy dispersive X-ray (EDX) system analysis revealed that the ion-exchange was an important mechanism involved in the Cu(II) and Cd(II) sorption process taking place on EPS.     

Total nitrogen and pH-controlled chemical speciation,bioavailability and ecological risk from Cd,Cr, Cu,Pb and Zn in the water level-fluctuating zone sediments of the Three Gorges Reservoir

We investigated the distribution and chemical speciation of Cd, Cr, Cu, Pb and Zn in the water level-fluctuating (WLF) zone of the main stream (MS) and tributaries (ZX and MX) of the Three Gorges Reservoir. We evaluated the ecological risk and pollution level from heavy metals based on the Potential Ecological Risk Index (RI), Risk Assessment Code (RAC), and Ratio of Secondary Phase and Primary Phase (RSP). Our results indicated that the total and bio-available heavy metal contents were higher in the tributaries than in the MS. Moderate pollution from Cd and light pollution from Pb were observed both at the MS and ZX sites, whereas the MX site exhibited a pattern of heavy Cd pollution and light Cr and Pb pollution. In our study area, the results indicated that Cd exhibited a higher ecological risk than did the other heavy metals. Finally, the pH and nitrogen content of sediments may play a key role in controlling the amount of heavy metal bioavailability, further inducing a higher potential ecological risk.     

Interactions between toxic (As, Cd, Hg and Pb) and nutritional essential (Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Zn) elements in the tissues of cattle from NW Spain

Since the toxicity of one metal or metalloid can be dramatically modulated by the interaction with other toxic or essential metals, studies addressing the chemical interactions between trace elements are increasingly important. In this study correlations between the main toxic (As, Cd, Hg and Pb) and nutritional essential (Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Zn) elements were evaluated in the tissues (liver, kidney and muscle) of 120 cattle from NW Spain, using Spearman rank correlation analysis based on analytical data obtained by ICP-AES. Although accumulation of toxic elements in cattle in this study is very low and trace essential metals are generally within the adequate ranges, there were significant associations between toxic and essential metals. Cd was positively correlated with most of the essential metals in the kidney, and with Ca, Co and Zn in the liver. Pb was significantly correlated with Co and Cu in the liver. A large number of significant associations between essential metals were found in the different tissues, these correlations being very strong between Ca, Cu, Fe, Mn, Mo and Zn in the kidney. Co was moderately correlated with most of the essential metals in the liver. In general, interactions between trace elements in this study were similar to those found in polluted areas or in experimental studies in animals receiving diets containing high levels of toxic metals or inadequate levels of nutritional essential elements. These interactions probably indicate that mineral balance in the body is regulated by important homeostatic mechanisms in which toxic elements compete with the essential metals, even at low levels of metal exposure. The knowledge of these correlations may be essential to understand the kinetic interactions of metals and their implications in the trace metal metabolism.     

Contamination of Floodplain Soils along the Wupper River,Germany, with As,Co, Cu,Ni, Sb,and Zn and the Impact of Pre-definite Redox Variations on the Mobility of These Elements

This study demonstrates that floodplain soils of the River Wupper, Germany, are seriously contaminated with metal(loid)s. We used an automated biogeochemical microcosm system allowing controlled variation of redox potential (E_H) to assess the impact of pre-definite redox conditions on the dynamics of arsenic (As), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), antimony (Sb), and zinc (Zn) in homogenized soil material taken from an acid floodplain soil. The concentrations of Co, Cu, Mn, Ni, Sb, and Zn in soil solution were low at low E_H, possibly due to the precipitation of metal sulfides, and increased with rising E_H, presumably caused by their association with dissolved organic carbon (DOC). A significant positive correlation between metal/DOC-ratio and E_H indicated that the binding of the metals to DOC shifted from stronger to weaker when E_H rose. Decreasing As concentrations with increasing E_H in soil solution indicated co-precipitation with Fe(hydr)oxides and/or oxidation of more soluble As(III) to less soluble As(V) during oxidation. The other studied elements seemed not to co-precipitate with newly formed Fe(hydr)oxides when E_H rose, possibly due to the prevailing low pH. In the future, the specific role of DOC and sulfur chemistry on metal(loid) dynamics should be elucidated more fully, and similar studies should be conducted with additional frequently flooded soils worldwide to verify these results.     

Agromyces sp.CS16去除水体中重金属镉、镍、铜、锌离子的研究北大核心

【目的】本研究从深圳福田红树林表层土壤中分离出一株潜在放线菌新种Agromyces sp.CS16,研究其对水体中重金属的去除能力以及特征,并初步探究其在去除水体重金属中的实际应用,为利用微生物修复水体重金属污染提供技术支持。【方法】测定菌株CS16对Cd^(2+)、Ni^(2+)、Cu^(2+)、Zn^(2+)的去除能力;测定CS16对Cd^(2+)、Ni^(2+)、Cu^(2+)、Zn^(2+)在胞外吸附和胞内吸收的占比;通过全基因组测序分析CS16基因组中与重金属耐受相关的基因;采用海藻酸钠和聚乙烯醇将CS16包埋,并测定包埋后CS16对重金属的去除能力。【结果】放线菌Agromyces sp.CS16在Cd^(2+)浓度为10μg/mL时对其的去除量最大,为32.95 mg/g,此时对溶液中Cd^(2+)的去除率也最高,达到83.71%;菌株CS16在Ni^(2+)浓度为75μg/mL时去除量最大,为25.09 mg/g,在Ni^(2+)浓度为25μg/mL时去除率最高,为70.27%;CS16在Cu^(2+)浓度为150μg/mL时去除量最大,为30.69 mg/g,在Cu^(2+)浓度为30μg/m L时去除率最高,为80.11%;CS16在Zn^(2+)浓度为125μg/mL时去除量最大,为39.29 mg/g,在Zn^(2+)浓度为25μg/mL时去除率最高,为88.91%。菌株CS16全基因组预测总共有3744个基因,其中有37个基因推测与Cd^(2+)、Ni^(2+)、Cu^(2+)、Zn^(2+)的抗性相关。CS16主要通过将重金属吸附在细胞外表面来去除水体中的重金属,在被海藻酸钠(sodium alginate,SA)与聚乙烯醇(polyvinyl alcohol,PVA)材料包埋后,CS16对Cd^(2+)的去除能力下降,但对Ni^(2+)、Cu^(2+)、Zn^(2+)的去除能力显著提高。【结论】放线菌Agromyces sp.CS16是一株分离自红树林表层沉积物的新菌,本研究测定了CS16对Cd^(2+)、Ni^(2+)、Cu^(2+)、Zn^(2+)的去除能力,从细胞层面和基因层面初步探索了其对Cd^(2+)、Ni^(2+)、Cu^(2+)、Zn^(2+)的去除机理,并成功用海藻酸钠和聚乙烯醇将其包埋,为探究微生物去除水体重金属离子的机制和之后应用CS16修复水体重金属污染提供了理论基础。     

Bioaccumulation and phyto-translocation of arsenic,chromium and zinc by Jatropha curcas L.: Impact of dairy sludge and biofertilizer

The present study was planned to remediate the metalloid and metal contaminated soil by using non-edible and economic plant species Jatropha curcas L. The experiment was conducted on pots to improve the survival rate, metal tolerance and growth response of the plant on soil; having different concentrations of arsenic, chromium and zinc. The soil was amended with dairy sludge and bacterial inoculum (Azotobacter chroococcum) as biofertilizer. The results of the study showed that the bioaccumulation potential was increased with increase in metalloid and metal concentration in soil system. Application of dairy sludge significantly reduces the DTPA-extractable As, Cr and Zn concentration in soil. The application of organic amendment stabilizes the As, Cr and Zn and reduced their uptake in plant tissues.     

Effect of EDTA and Tannic Acid on the Removal of Cd,Ni, Pb and Cu from Artificially Contaminated Soil by Althaea rosea Cavan

In this study an ornamental plant of Althaea rosea Cavan was investigated for its potential use in the removal of Cd, Ni, Pb and Cu from an artificially contaminated soil. Effect of two different chelating agents on the removal has also been studied by using EDTA (ethylenediaminetetracetic acid) and TA (tannic acid). Both EDTA and TA have led to higher heavy metal concentration in shoots and leaves compared to control plants. However EDTA is generally known as an effective agent in metal solubilisation of soil, in this study, TA was found more effective to induce metal accumulation in Althaea rosea Cavan under the studied conditions. In addition to this, EDTA is toxic to some species and restraining the growth of the plants. The higher BCF (Bio Concentration Factor) and TF (Translocation Factor) values obtained from stems and leaves by the effects of the chemical enhancers (EDTA and TA) show that Althaea rosea Cavan is a hyper accumulator for the studied metals and may be cultivated to clean the contaminated soils.     

Leaching of Cd,Zn, Pb,and Cu in Packed and Undisturbed Columns of Soils Affected by the Spill from a Pyrite Mine in the South of Spain

A study has been made of the leaching of Cd, Zn, Pb, and Cu in three representative soils within the zone affected by the spill from a pyrite mine in Aznalcollar (Sevilla, Spain) employing packed soil columns. According to the breakthrough and cumulative leaching curves, the relative mobilities of the different toxic elements in the columns are as follows: Cd> Zn> Cu> Pb. The effect of leaching on the distribution of metals as a function of depth using intact soil cores was also studied. The results showed that the soils themselves have a good capacity for immobilizing the soluble fraction of the elements from the spilled mud. This capacity varied as follows: clayey soil with a high carbonate content > clayey soil with a moderate carbonate content > sandy-clay loam soil with a low carbonate content. However, sandy soils with a low carbonate content could pose a risk to groundwater if initial contamination was high. These results could be considered during the evaluation of remedial technologies for the immobilization of soil metals.     

Towards absolute asymmetric synthesis. Synthesis and crystal structure of stereochemically labile MCl2 (M = Co, Ni, Cu, Zn) complexes with diamine ligands

In search for new conglomerates, seven stereochemically labile complexes between MCl₂ (M = Co, Cu, Ni, Zn) and bidentate ligands, the commercially available N,N,N′-trimethylethane-1,2-diamine (trimeda) and the somewhat bulkier N-isopropyl-N,N′,N′-trimethylethane-1,2-diamine (itmeda), have been synthesized and characterized using single crystal X-ray diffraction. The trimeda and itmeda ligands exhibit chirogenic nitrogen centers and may form chiral metal complexes that are candidates for total spontaneous resolution. Copper(II) chloride forms the dimeric meso complexes [{CuCl₂(trimeda)}₂] (1) and [{CuCl₂(itmeda)}₂] (2), while [CoCl₂(trimeda)₂] (3) and [NiCl₂(trimeda)₂] (4) exhibit six-coordinate but chiral (R,R)- and (S,S)-complexes. Three examples of the chiral target complex, comprising four-coordinate stereochemically labile monomers, was successfully prepared, viz. [NiCl₂(itmeda)] (5), [ZnCl₂(itmeda)] (6), and [CoCl₂(itmeda)] (7).In all seven complexes, the λ-conformation of the five-membered trimeda-metal chelate ring corresponds to the (S)-configuration at nitrogen, and vice versa. Supramolecular interactions in 3 and 4 form hydrogen-bonded heterochiral ribbons. However, crystals of 5-7 display homochiral interactions resulting in polar phases. Weak CH-Cl interactions in 5 and 6 form homochiral layers. In 7, interactions form homochiral helices along the a-axis.     

Synthesis, structures and DNA binding of ternary transition metal complexes M(II)L with the 2,2-bipyridylamine (L = p-HB, M = Co, Ni, Cu and Zn)

New ternary transition metal complexes of formulations [Co(bpa)(p-HB)₂](bpa = 2,2′-bipyridylamine, p-HB = p-hydroxybenzenecarboxylic acid) (1), [Ni(bpa)(p-HB)(H₂O)₂]⁺(NO₃)⁻ · H₂O (2), , [Cu(bpa)(p-HB)Cl] (4) and [Zn(bpa)(p-HB)₂]₂ · 0.5H₂O (5) are prepared, their structural features are characterized by crystal structural studies, and their DNA binding propensity has been evaluated by fluorescence method. The molecular structure of complex 1 shows the six coordinate octahedral geometry with one bpa and two p-HB ligands, complex 2 is the cationic complex and has the six coordinate octahedral structure with one bpa, one p-HB and two aqua ligands, complex 3 is also the cationic complex of octahedral coordination with two bpa and one p-HB ligands, complex 4 is five coordinate distorted square pyramidal with one bpa, one p-HB and chloride ligands and complex 5 has the distorted octahedral coordination with two p-HB and one bpa ligands. In all of the complexes, both bpa and p-HB act as the bidentate N and O-donor ligands, respectively. The intermolecular H-bond networks, together with π-π interaction in their solid state are also described. The complexes show the competitive inhibition of ethidium binding to DNA, and the DNA binding propensity can be reflected as the relative order: 3 > 2 > 1 > 5 > 4, in which the cationic charged Ni(II) complexes 2 and 3 show the most effective inhibition ability.     

Purification, characterisation, and inhibition by monoterpenes of acetylcholinesterase from the waxmoth, Galleria mellonella (L.)

Acetylcholinesterase (AChE) was purified from the brain of the waxmoth, Galleria mellonella (L.) by affinity chromatography followed by anion exchange chromatography. It resolved as a single band by polyacrylamide gel electrophoresis (PAGE) both non-denaturing and SDS (silver stained), and as a single peak by high pressure liquid chromatography (HPLC), in an overall yield of 32% representing 283-fold purification. This was a true acetylcholinesterase, with no activity as a non-specific cholinesterase (butyrylcholinesterase). The molecular weight determined by PAGE in the absence and presence of sodium dodecyl sulphate (SDS) was ca. 240,000 Da and 60,000 Da respectively, indicating an arrangement of tetrameric subunits. 2-Heptanone, the honeybee alarm pheromone, reversibly and competitively inhibited the purified Galleria AChE with a K_i value of 1.34×10⁻³ M. Furthermore, five monoterpenes associated with plant defence and representing a range of functional groups, also were reversible competitive inhibitors of the purified AChE from Galleria, which is consistent with previous data for electric eel AChE (Ryan, M.F., Byrne, O., 1988. Plant-insect coevolution and inhibition of acetylcholinesterase. Journal of Chemical Ecology 14, 1965-1975).     

Simultaneous measurement of the trace elements Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum and their reference ranges by ICP-MS

The goal of this article was to establish reference ranges of the concentration of trace elements in human serum and to compare these results with those reported by other authors. We describe the sample preparation and measurement conditions that allow the rapid, precise, and accurate determination of Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum samples (n=110) by inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy and precision were determined by analyzing three reconstituted reference serum samples by comparison with other methods and by the standard addition procedure. The advantages of the ICP-MS method include short time of analysis of the elements mentioned, low detection limit, high precision, and high accuracy. Disadventages include a high risk of contamination due to the presence of some of the elements of interest in the environment, the relatively delicate sample handling, and the high cost of the equipment.     

Effects of anions, acetazolamide, thiocyanate and amiloride on fluid secretion by the Malpighian tubules of Locusta migratoria L.

The effect of Cl⁻, HCO₃⁻, Br⁻, acetazolamide, thiocyanate and amiloride on urine formation in Locusta migratoria Malpighian tubules have been determined. The rate of fluid secretion depends markedly on the concentration of Cl⁻ in the bathing solution with concentrations less than 90 mM resulting in reduced fluid secretion. Substitution of Br⁻ for Cl⁻ had no significant effect on the rate of the fluid secretion. Replacement of NaHCO₃ with NaCl in Hepes buffered Ringer solution reduced the rate of urine production by 23%. Fluid secretions were reduced in the presence of 10⁻⁴–10⁻² M acetazolamide, a carbonic anhydrase inhibitor. The combined effect of acetazolamide in the absence of HCO₃⁻ appears to be additive. A 1 mM concentration of thiocyanate, an ionic inhibitor, reduced fluid secretion by 35%. Amiloride interferes with the electrogenic entry of Na⁺ into the cell and a 1 mM solution reduced fluid secretion by 94% with secretion completely inhibited in 80% of the tubules tested.