Copper-tolerant Species Research Articles

Copper chloride (II) effect on the composition and structure of marine microphytobenthic communities.

To assess the temporary effects of the increased copper ion inflow on estuarine microphytobenthic communities, ecotoxicological tests were conducted using natural microphytobenthic assemblages obtained from an artificial substratum exposed to the waters of the southern Baltic Sea (Gulf of Gdańsk). The applied copper ion concentrations reflected permitted copper values established for waters of a good ecological status (2·10-5g Cu·dm-3), and the maximum copper concentrations which, according to the current environmental regulations, are allowed to be discharged into the environment (2·10-3g Cu·dm-3).In the studied communities, diverse responses of single species to CuCl2 exposure were recorded, including both growth inhibition and stimulatory effects as well. Despite the shift in the community composition and structure, total cell number remained at a similar level. The results of our investigations suggest that microphytobenthic assemblages are resistant to CuCl2 which is facilitated by the shift in the community composition resulting from the increasing cell number of copper tolerant species.

Evaluation of Streptomyces species from historically sewage sludge contaminated soils for tolerance to copper(II) toxicity

Pollution of the environment by copper(II) exerts numerous adverse impacts on soils, microorganisms, plants, animals and humans. Assessing these impacts on microorganisms is essential as they are potential agents of bioremediation to purify the ecosystem. The aim of this study was to investigate the tolerance of Streptomyces species obtained from historically contaminated soils to copper (II) toxicity. Soil samples were collected from farms around sewage sludge dump sites (tests) and where there were no dumps (control). Standard microbiological methods were used to isolate, characterize and identify the three best copper tolerant species. Also, the impact on Streptomyces growth characteristics such as radial growth (R2), index of growth (GI) and percentage inhibition of radial growth (PIRG) by copper (II) was examined. Results obtained indicated that; the minimum inhibitory concentration of copper (II) for some of the Streptomyces isolates was 600 mg/l. However, three isolates; SW2B, SW7A and SW7B had MIC of 3000 mg/l and were selected for further investigations. Increasing metal concentration from 100 mg/l to 2000 mg/l reduced R2 from 40.2 to 4.0 and GI from 0.77 to 0.08, corresponding to 69.48 % increase in PIRG for SW2B. For isolate SW7A, R2 and GI decreased from 33.7 to 3.8 and from 0.67 to 0.08 respectively as copper (II) concentration increased from 100 mg/l to 2000 mg/l, giving 59.33 % increase in PIRG. The highest increase in PIRG (88.04 %) was obtained for SW7B, corresponding to a decrease of R2 and GI from 39.2 to 5.2 and 0.77 to 0.10 respectively. Molecular method was used to identify the isolates as Streptomyces chartreusis (SW2B), Streptomyces aureoverticillatus (SW7A) and Streptomyces subrutilus (SW7B).

Life-history strategies in zooplankton promote coexistence of competitors in extreme environments with high metal content

The toxicity of pollutants on aquatic communities is determined by the specific sensitivities and by the ecological relationships between species, although the role of ecological interactions on the specific sensitivity to pollutants is complex. We tested the effect of exposure to copper on the life-history strategies of two coexisting rotifer species of the genus Brachionus from Inca-Coya lagoon, an isolated water body located in Atacama Desert. The experiments looked at differences in the response to the stress by chemical pollution mimicking field conditions of copper exposure, levels of food, and salinity, between single-species cultures and coexisting species. Under single species cultures, B. ‘Nevada’ had lower densities, growth rates, and resting eggs production than B. quadridentatus; when in competition, B. ‘Nevada’ performed better than B. quadridentatus in most life-history traits. B. ‘Nevada’ was a copper-tolerant species, which outcompeted B. quadridentatus, more copper-sensitive, with higher levels of copper. Species-specific responses to environmental conditions and pollution, plus differential relationships between population density and production of resting eggs, resulted in reduced niche overlap between species, allowing stabilized coexistence. The extreme environmental conditions and the isolation of the Inca-Coya lagoon, make it an excellent model to understand the adaption of aquatic organisms to stressed environments.

Phytoremediation Potential of Copper Contaminated Soils in <i>Calendula officinalis</i> and Effect of Salicylic Acid on the Growth and Copper Toxicity

The present research was carried out to assess the effectiveness Calendula officinalis on removing the Cu from the contaminated soil and to examine the effects of salicylic acid (SA) on growth and some eco-physiological, biochemical characteristics in plants exposed to copper stress. This experiment was arranged as a factorial experiment based on completely randomized design with four replications in greenhouse conditions. The experimental treatment consisted of four levels of Cu (0, 100, 200, and 400 mg/kg in potted soil) and three levels of salicylic acid (0, 1, 2mM) as foliar spray and chelate into soil. Results showed that with increasing levels of copper, reductions in shoot and root growth, leaf area and leaves number were statistically significant at 1 percent level. Although the copper concentration in shoots of Calendula officinalis could not exceed 1,000 mg/kg dry weight, the results showed that copper accumulation was higher in the shoots than in the roots. The results of the concentration of copper showed that translocation (TF) and bio-concentration factor (BCF) was greater than 1. Thus, Calendula officinalis could be classified as a copper tolerant species. Application of SA was found to alleviate negative effects generated by heavy metals like copper in plants. SA significantly increased growth and resistance index in copper stressed plants. SA as chelate in concentration of 2mM had the greatest effect on studied parameters. Results showed that salicylic acid can increase the efficiency of phytoremediation successfully.

Phytoremediation Potential of Copper Contaminated Soils in <i>Calendula officinalis</i> and Effect of Salicylic Acid on the Growth and Copper Toxicity

The present research was carried out to assess the effectiveness Calendula officinalis on removing the Cu from the contaminated soil and to examine the effects of salicylic acid (SA) on growth and some eco-physiological, biochemical characteristics in plants exposed to copper stress. This experiment was arranged as a factorial experiment based on completely randomized design with four replications in greenhouse conditions. The experimental treatment consisted of four levels of Cu (0, 100, 200, and 400 mg/kg in potted soil) and three levels of salicylic acid (0, 1, 2mM) as foliar spray and chelate into soil. Results showed that with increasing levels of copper, reductions in shoot and root growth, leaf area and leaves number were statistically significant at 1 percent level. Although the copper concentration in shoots of Calendula officinalis could not exceed 1,000 mg/kg dry weight, the results showed that copper accumulation was higher in the shoots than in the roots. The results of the concentration of copper showed that translocation (TF) and bio-concentration factor (BCF) was greater than 1. Thus, Calendula officinalis could be classified as a copper tolerant species. Application of SA was found to alleviate negative effects generated by heavy metals like copper in plants. SA significantly increased growth and resistance index in copper stressed plants. SA as chelate in concentration of 2mM had the greatest effect on studied parameters. Results showed that salicylic acid can increase the efficiency of phytoremediation successfully.

Analysis on the Tolerance of Four Ecotype Plants Against Copper Stress in Soil

To screen copper tolerant species, Four ecotype plants, Catalpabungei C. A. Mey, Catalpa ovata G. Don, tall fescue (Festuca arundinacea), and Sedum lineare Thunb, were planted in soil contaminated by Cu in greenhouse to reveal their characteristics of survival, growth and morphology, as well as copper uptake, accumulation and translocation in plants. The survival rate(S) of Catalpabungei C. A. Mey under Cu stress was high, while that of Catalpa ovata G. Don was just the opposite. With the increasing of Cu concentrations in soil, tree height(H) increment percents of both Catalpabungei C. A. Mey and Catalpa ovata G. Don declined significantly(significant level, α=0.05), but for stem bases(D) there were not obvious differences. The translocation factors (TF) and bioconcentration factors(BCF) of Catalpabungei C. A. Mey and Catalpa ovata G. Don were both lower than 0.5. The Cu content in roots of Catalpabungei C. A. Mey was significantly positively correlated with that in soil(r = 0.98; P < 0.05). Tolerance index (TI) of tall fescue and Sedum lineare Thunb were low. The concentrations of Cu in tall fescue and Sedum lineare Thunb both had significantly positive correlation with those in soils. The results suggested that Catalpabungei C. A. Mey, tall fescue, and Sedum lineare Thunb were tolerant to Cu stress in soil to some extent, and were of application potential as pioneer species for ecological restoration in areas suffering Cu pollution.

Genetic diversity and characterization of heavy metal-resistant-endophytic bacteria from two copper-tolerant plant species on copper mine wasteland

The diversity of endophytic bacteria from the copper-tolerant species Elsholtzia splendens and Commelina communis was evaluated by using cultivation and cultivation-independent techniques. Phylogenetic analysis based on 16S rDNA sequences showed that the Cu-resistant isolates belonged to three major phylogenetic groups: Firmicutes, Actinobacteria and Proteobacteria. Bacillus and Acinetobacter were predominant among the Cu-resistant isolates. Sequence analysis from the 16S rDNA clone libraries of the two plant roots revealed sequences of Alpha-, Beta-, Gamma- Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Gammaproteobacteria was predominant in the two 16S rDNA clone libraries. Thirty-two endophytic bacteria were isolated and characterized with respect to heavy metal resistance and production of plant growth-promoting factors. In experiments involving rape plants grown in vermiculite containing 4 mg kg −1 of Cu, inoculation with the isolates was found to increase the dry weights of roots (ranging from 132% to 155%) and above-ground tissues (ranging from 71% to 83%) compared to the uninoculated control. Increase in above-ground tissue Cu content varied from 63% to 125% in inoculated-rape plants cultivated in Cu-contaminated substrate compared to the uninoculated control.

Uptake and internalisation of copper by three marine microalgae: Comparison of copper-sensitive and copper-tolerant species

Although it has been well established that different species of marine algae have different sensitivities to metals, our understanding of the physiological and biochemical basis for these differences is limited. This study investigated copper adsorption and internalisation in three algal species with differing sensitivities to copper. The diatom Phaeodactylum tricornutum was particularly sensitive to copper, with a 72-h IC50 (concentration of copper to inhibit growth rate by 50%) of 8.0 μg Cu L −1, compared to the green algae Tetraselmis sp. (72-h IC50 47 μg Cu L −1) and Dunaliella tertiolecta (72-h IC50 530 μg Cu L −1). At these IC50 concentrations, Tetraselmis sp. had much higher intracellular copper (1.97 ± 0.01 × 10 −13 g Cu cell −1) than P. tricornutum (0.23 ± 0.19 × 10 −13 g Cu cell −1) and D. tertiolecta (0.59 ± 0.05 × 10 −13 g Cu cell −1), suggesting that Tetraselmis sp. effectively detoxifies copper within the cell. By contrast, at the same external copper concentration (50 μg L −1), D. tertiolecta appears to better exclude copper than Tetraselmis sp. by having a slower copper internalisation rate and lower internal copper concentrations at equivalent extracellular concentrations. The results suggest that the use of internal copper concentrations and net uptake rates alone cannot explain differences in species-sensitivity for different algal species. Model prediction of copper toxicity to marine biota and understanding fundamental differences in species-sensitivity will require, not just an understanding of water quality parameters and copper-cell binding, but also further knowledge of cellular detoxification mechanisms.

Studies on preservative tolerant Phialophora species

Phialophora species are shown to possess a variable capacity for growth on either copper, arsenic or copper-chrome-arsenic (CCA) supplemented laboratory media. The most copper tolerant species. Phialophora sp. A, P. malorum and P. mutabilis, were also the most arsenic resistant. Fine structural studies have shown intra- and to a lesser extent extracellular localization of copper which may provide a means of tolerating high external copper levels under culture conditions. Wood decay experiments have shown Phialophora spp. to have a good capacity to degrade K33 treated birch after 7·5 months but not pine, despite colonization. The most important wood degrading Phialophora were also the more copper/arsenic resistant species although non-tolerant species were also able to degrade treated birch. A comparison between the extreme copper levels tolerated by selected species with the amount of copper in treated wood may suggest that only sub-toxic levels may be obtained, levels which may not require special detoxification mechanisms for either colonization or decay in wood. In this respect, factors other than toxicity, particularly the nature of the substrate (e.g. lignin type and level) and reaction with CCA and ammoniacal-copper during treatment may be of greater significance.