Chemical elements in the mineralization of plant residues under soil pollution with heavy metals

Mineralization processes of plant residues in background and anthropogenically affected areas are analyzed. The multielement composition of plant residues before and after their exposure in soil is provided with the help of synchrotron radiation (XPA SR). It is demonstrated that the destruction process is accompanied by changes in the chemical composition of plant residues. Chemical elements with concentrations increasing as they are filtrated from soil into the exposed samples are determined. Agrobotanical groups of plants with the highest infiltration rate are revealed.     

The biochemistry of environmental heavy metal uptake by plants: Implications for the food chain

Plants absorb a number of elements from soil, some of which have no known biological function and some are known to be toxic at low concentrations. As plants constitute the foundation of the food chain, some concerns have been raised about the possibility of toxic concentrations of certain elements being transported from plants to higher strata of the food chain. Special attention has been given to the uptake and biotransformation mechanisms occurring in plants and its role in bioaccumulation and impact on consumers, especially human beings. While this review draws particular attention to metal accumulation in edible plants, researched studies of certain wild plants and their consumers are included. Furthermore, this review focuses on plant uptake of the toxic elements arsenic, cadmium, chromium, mercury, and lead and their possible transfer to the food chain. These elements were selected because they are well-established as being toxic for living systems and their effects in humans have been widely documented. Arsenic is known to promote cancer of the bladder, lung, and skin and can be acquired, for example, through the consumption of As-contaminated rice. Cadmium can attack kidney, liver, bone, and it also affects the female reproduction system. Cadmium also can be found in rice. Chromium can produce cancer, and humans can be exposed through smoking and eating Cr-laden vegetables. Lead and mercury are well known neurotoxins that can be consumed via seafood, vegetables and rice.     

Mechanism of induction of cytogenetic damage in plant meristematic cells caused by combined effect of heavy natural radionuclides and heavy and alkaline metals

The analysis of experimental data on the combined effect of 232Th and water from melted snow containing metal ions from industrally loaded territories on Tradescantia (clone 02) and on Allium shoenoprasum meristematic root tip cells treated with heavy natural radionuclides from natural water sources in the area of radioactive wastes storehouse is presented. It was demonstrated that plant meristematic cells response to heavy metals and heavy natural radionuclides, both from two-component model system and from natural water sources, have commom features.     

Bioaccumulation and translocation of heavy metals by Plantago major L. grown in contaminated soils under the effect of traffic pollution

The present study was performed at a heavy-traffic affected soil to examine the efficacy of bioaccumulation and translocation potentials of heavy metals by the naturally growing weed Plantago major. Heavy metals were analyzed in soil as well as in plant below- and above-ground parts along different distances from a heavy-traffic highway. All the investigated soil heavy metals, except Cd, varied significantly, while pH and E.C had no significant difference, with increasing distance from the highway. Likewise, there was a significant decrease of heavy metals in plant below- and aboveground parts. In addition, no significant difference between most soil and root heavy metals at 20 and 100 m as well as those at 500 and 750 m distance from the highway. The bioaccumulation factor (BF) of all heavy metals, except Cd and Sr, were less than unity at most distances. However, Cd showed relative BF decline with the distance in contrast to Sr, which increases as distance from the highway increases. On the other hand, the translocation factors (TF) of Cd, Co, Cu, Pb and Zn were higher at the distances far from the highway, while that of Fe, Cr and Sr were higher near the highway. Furthermore, the enrichment factor (EF) showed small variations, among the investigated heavy metals, with varying distances from the pollution source. It was found that soil Fe, Al, Cr, Ni, Sr, V and Zn had significant positive correlation with all investigated heavy metals in P. major roots. The higher TFs of Cd, Fe and Pb in P. major shoots makes it suitable for phytoextraction from soil, while the lower ratios of Al, Mn, V, Co, Ni, Cr, Zn, Cu and Sr make it suitable for their phytostabilization. Therefore, this plant can be used as a bioindicator and biomonitor for traffic related heavy metals.     

The effect of heavy chain phosphorylation and solution conditions on the assembly of Acanthamoeba myosin-II

At low ionic strength, Acanthamoeba myosin-II polymerizes into bipolar minifilaments, consisting of eight molecules, that scatter about three times as much light as monomers. With this light scattering assay, we show that the critical concentration for assembly in 50-mM KCl is less than 5 nM. Phosphorylation of the myosin heavy chain over the range of 0.7 to 3.7 P per molecule has no effect on its KCl dependent assembly properties: the structure of the filaments, the extent of assembly, and the critical concentration for assembly are the same. Sucrose at a concentration above a few percent inhibits polymerization. Millimolar concentrations of MgCl2 induce the lateral aggregation of fully formed minifilaments into thick filaments. Compared with dephosphorylated minifilaments, minifilaments of phosphorylated myosin have a lower tendency to aggregate laterally and require higher concentrations of MgCl2 for maximal light scattering. Acidic pH also induces lateral aggregation, whereas basic pH leads to depolymerization of the myosin- II minifilaments. Under polymerizing conditions, millimolar concentrations of ATP only slightly decrease the light scattering of either phosphorylated or dephosphorylated myosin-II. Barring further modulation of assembly by unknown proteins, both phosphorylated and dephosphorylated myosin-II are expected to be in the form of minifilaments under the ionic conditions existing within Acanthamoeba.     

Bioreduction of precious and heavy metals by Candida species under oxidative stress conditions

The aim of the present work was to evaluate whether Candida species can reduce both precious and toxic pure metals from the respective molecular ions. From these results, the nanoparticles formed were studied using scanning electron microscopy with energy-dispersive spectroscopy, Raman spectroscopy, X-ray fluorescence spectroscopy and synchrotron radiation. Our results showed that the metal ions were reduced to their corresponding metallic nanoconglomerate or nanoparticles by Candida species. This is the first report on how yeasts of this genus are capable of achieving homeostasis (resilience) in the presence of metal ions of both precious and toxic metals by reducing them to a metallic state.     

植物对环境应力刺激的生物学效应

植物生长在自然环境中由于其“不动性”而不可避免地要受到各种环境应力的刺激,应力－生长关系一直是生物学家和物理学家所关心的课题,是生物力学的灵魂。很多研究已经表明外界应力作用对植物的生长发育有着重要的影响。本综述了国内外关于应力对植物组织所引起的生物学效应,首先论述了环境应力所引起的宏观生物学效应,随后重点论述了环境应力所引起的生物学效应在细胞和分子水平上的研究,其中包括单个细胞的加载、电磁场、微     

Abnormalities of embryonal development of vertebrates under the conditions of technogenic environmental pollution

The performed investigations have revealed 21 kinds of pathologies in the embryonal development of amphibia and more than 30 kinds in small mammals in the territories with radiation-chemical environmental pollution. Differences in embryonal mortality and pathologies of embryogenesis have been demonstrated for both the representatives of amphibia and mammals and within one class in the regions with different technogenic load. Embryonàl death and pathologies of embryonal development are considered as important reasons of reproductive losses for different species.     

Distribution and health risk assessment of heavy metals in soil surrounding a lead and zinc smelting plant in Zanjan,Iran

One of the problematic issues in soil pollution studies is heavy metal particles which are produced by mines and smelting units and spread through wind action and/or runoff. Pollution and health risk assessment of cadmium, lead, zinc, copper, and nickel in soil around the lead and zinc smelting factory was carried out in Zanjan City, Iran. Contamination factor (Cf), pollution load index (PLI), geoaccumulation index (Igeo), hazard quotient (HQ), hazard index (HI), and carcinogenic risk were pollution and human health risk assessment metrics in this study. Based on the Iranian soil guideline value, soil samples in the studied areas were contaminated the least by copper and nickel and the most by cadmium. PLI results showed that soils near the production line were heavily or extremely heavily polluted. The results of Cf and Igeo showed that lead and zinc were the most important contaminants. Health risk assessment indicated that lead and cadmium in soil were the main contaminants, which pose both carcinogenic and non-carcinogenic risks to human health; carcinogenic risk levels were unacceptably high (above 1 × 10^?4). It can be concluded that mining and smelting activities degrade soil quality in this region and the soil pollution might be extended to farming areas.     

Joint effects of dimethoate and heavy metals on metabolic responses in a grasshopper (Chorthippus brunneus) from a heavy metals pollution gradient

We studied how an exposure to an additional stressing factor-dimethoate, might affect detoxifying ability of grasshoppers collected at 5 meadow sites located along a heavy metal pollution gradient. Activities of esterases and enzymes linked with glutathione (GSH) metabolism were assayed 24 h after topical treatment with 0.32 microg dimethoate per insect. Inhibition of acetylcholinesterase (AChE) reaches nearly 50% of the value stated in untreated insects, without significant site-dependent differences. The pesticide also caused a significant decrease in activities of glutathione peroxidase (GPx) followed by a decrease in GSH levels in grasshoppers from all assayed groups, demonstrating high sensitivity of glutathione-dependent metabolism to the additional stressing factor. In the case of glutathione reductase (GR) and carboxylesterases (CarE) the fall of activity was shown especially in insects from less polluted meadows and the reference site. Glutathione reductase (GR) activity in individuals treated with dimethoate did not decrease only in insects from the most contaminated site I. This might suggest the trade-off mechanisms adapting grasshoppers to life in seriously polluted environments.     

An assessment of level of heavy metals pollution in the water,sediment and aquatic organisms: A perspective of tackling environmental threats for food security

Pollution is severely threatening the wetland habitats. Heavy metals are one among of the major pollutants in wetland habitats. The cadmium (Cd), copper (Cu), chromium (Cr), cobalt (Co), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn), were assessed in the water, sediment, benthic species (polychaetes, mollusc and crustaceans), prawn and fishes. The assessment of heavy metals was done by using double-beam Atomic Absorption Spectrophotometer (AAS). The Hg, Cr and Co were greater in sediment, Ni and Cd were higher in polychaetes and molluscs respectively. However, the Cu and Pb greater in crabs and the Zinc was greater in fishes. The concentration of metals showed significant differences among the various sources examined (P < 0.05) except Cr (P > 0.05). The inter-correlational analysis among the metals assessed from the various sources showed that the Cr and Pb not correlated among the eight metals examined. However, the Cu and Co were correlated with Hg (r = 0.307) and (r = 0.788) respectively. The nickel was correlated with Hg (r = 0.367), Cu (r = 0.362) and Co (r = 0.432). The Zinc was correlated with the Cd (r = 0.331) and Hg (r = 0.737). However, correlation of metals among the different sources shown that the metals of polychaetes correlated with sediment r = 0.637, the metals of crabs correlated with the sediment and polychaetes r = 0.630 and r = 842 respectively, the metals of molluscs was also correlated with sediment (r = 0.636), polychaetes (r = 0.889) and crabs (r = 0.894). In addition to that the metals of prawns was correlated with the polychaetes (r = 839), crabs (r = 0.628) and molluscs (r = 0.634). The metals of fishes correlated with polychaetes (r = 0.529), crabs (r = 0.710), molluscs (r = 0.493) and prawns (r = 0.593). Indeed the multiple regression model explained that the metals of sediments influence the accumulation of metals in biotic species such as polychaetes, molluscs, crustaceans, prawns and fishes with 84% (F = 21.079; p < 0.001).The order of the heavy metals in the water, sediment and biotic species was Hg > Pb > Ni > Cr > Zn > Co > Cu > Cd. The study found that the level of heavy metals at various sources in the sanctuary is showing considerable warning and the sanctuary is required intensive assessment on various aspects of pollution since the Point Calimere Wildlife Sanctuary is supporting several species of migratory and endangered shorebirds seasonally.     

The effect of polyvinylpyrrolidone (PVP) on the heavy chain monoclonal antibody production from plant suspension cultures

A heavy chain monoclonal antibody (HC MAb) was produced by the suspension cultures of genetically modified tobacco cells. Though the HC MAb was secreted to the culture medium by the cells, it was unstable in plant cell media. The addition (0.75 g/L) of polyvinylpyrrolidone (MW 360,000) to the medium stabilized the extracellular HC MAb and increased its production 35 fold to 350 g/l.     

The cytotoxic effect of heavy metals on an L-cell culture

The dependence of some parameters of L-cells culture viability on different concentrations of heavy metals was studied. Considerable cytotoxic effect of low concentrations of nickel (0.025 mcg/ml) and lead (0.05 mcg/ml) was shown. Copper and chrome at concentrations of 0.25-0.5 mcg/ml promote cells proliferation between third and fifth days of cultivation. Nickel at concentration 0.025 mcg/ml and lead at all investigated concentrations synchronize cells division in culture. Increasing of giant polynucleas cells level in culture was characteristic for investigated metals. The maximum levels of this type cells were caused by the action of nickel, chrome and copper.     

Toxic effects caused by heavy metals in the yeast Saccharomyces cerevisiae: a comparative study

The decreasing order of toxicity of select heavy metals on the yeast Saccharomyces cerevisiae, in 10 mM MES (2-(N-morpholino)ethanesulfonic acid) pH buffer at pH 6.0, was found to be copper, lead, and nickel. Heavy metal (200 microM) induced a decrease in the number of viable cells by about 50% in the first 5 min for copper and in 4 h for lead, while nickel was not toxic up to a 200 microM concentration over a period of 48 h. Glucose (25 mM) strongly enhanced the toxic effect of 50 microM copper but had little or no effect on the toxicity of 200 microM lead or nickel. Copper, lead, and nickel induced the leakage of UV260-absorbing compounds from cells with different kinetics. The addition of 0.5 mM calcium, before addition of 200 microM copper, showed a protective action against cell death and decreased the release of UV-absorbing compounds, while no effect was observed against lead or nickel toxic effects. Copper complexation capacities of the filtrates of cells exposed for 2 h in 200 microM copper and 24 h in 200 microM lead were 51 and 14 microM, respectively. The implication of the complexation shown by these soluble compounds in the bioavailability of heavy metals is discussed.     

The effects of heavy metals pollution of the upper Arkansas River on the distribution of aquatic macroinvertebrates

Water quality, types, and diversity of aquatic macroinvertebrates show that heavy metal pollution of the upper Arkansas River is presently moderately severe and conditions for aquatic life are generally poor, particularly in the Leadville area. A 2 year study was done on a 30 km section of the upper Arkansas River, Colorado, to determine the effects of heavy metals pollution on the distribution of the aquatic macroinvertebrates. Physical and chemical water parameters were measured, and aquatic macroinvertebrates were collected. The major sources of heavy metal-laden inflows are Leadville Drain, California Gulch, and a number of intermittent flows entering the Arkansas River between Lake Fork and Lake Creek. Important freshening flows are Tennessee Creek, Lake Fork (containing Halfmoon Creek), and Lake Creek.     

The production of a cold-induced extracellular biopolymer by Pseudomonas fluorescens BM07 under various growth conditions and its role in heavy metals absorption

The psychrotrophic bacterium Pseudomonas fluorescens BM07 was induced to excrete an extracellular biopolymer when cells were grown aerobically at 10 °C and its secretion was inhibited at 30 °C. The biopolymer was easily torn apart from the cells by using a shear force under centrifugation (8700 × g, 30 min) and collected as a well-separated mucoid layer in centrifuge tube. The production of the biopolymer was affected by factors such as the types of carbon and nitrogen sources, temperature, and pH. The best production of 2.5 g/l was obtained when the cells were grown on M1 medium containing 70 mM sucrose and 0.2% (w/v) Casamino Acids. In Kings B enriched medium a maximum biopolymer production of up to 3.4 g/l and growth rate of 2.1 g/l, were achieved using 1:1 ratio of C/N. Addition of NaCl and ethanol to the medium led to a decrease in biopolymer production and growth rate of BM07 strain. FT-IR spectroscopy demonstrated the presence of carboxyl, amine, hydroxyl and methoxyl functional groups in the biopolymer. BM07 biopolymer showed high ion binding capacity with particular preference to uptake cadmium and mercury (∼45 and 70%, respectively). The percentage removal of cobalt, zinc, nickel and copper cations were between 20 and 30%. Overall ion uptake by BM07 biopolymer showed a definite preference for larger over smaller cations (Hg > Cd > Ni > Zn > Cu > Co).