Tissue Concentrations Of Cu Research Articles

Dietary copper improves growth and regulates energy generation by mediating lipolysis and autophagy in hepatopancreas of Pacific white shrimp (Litopenaeus vannamei)

Copper is an essential micronutrient for living organisms, but its biological function has not been sufficiently studied, especially in crustaceans. Therefore, the present study aimed to evaluate the role of copper in the maintenance of energy homeostasis by mediating lipid and energy metabolism in Litopenaeus vannamei. L. vannamei (initial weight 0.90 ± 0.00 g) were fed diets containing 12.4 (Cu12.4), 22.0 (Cu22.0), 31.0 (Cu31.0), 41.7 (Cu41.7) and 49.8 (Cu49.8) mg kg−1 Cu for 8 weeks. Lipid and energy metabolism-related biochemical and molecular parameters were determined, and ultrastructural observation performed in hepatopancreas. Growth performance, tissue Cu deposition, antioxidant parameters, and expression of genes involved in Cu homeostasis and autophagy were also evaluated. Dietary copper supplementation improved growth, Cu concentration in tissue, and antioxidant capacity compared to the Cu-deficient diet. Copper promoted lipolysis and β-oxidation, confirmed by elevated expression levels of cpt1, ampkγ, acbp, acadl, acadm, acadvl, acox1, acox3 and decreased expression of srebp, acc1, 6pgd, and markedly increased activities of LPS and CPT1 and decreased ACC activity. Expression levels of genes related to autophagy (atg13, atg3, atg12, atg9, beclin1) were up-regulated, and autolysosomes and autophagosome were observed in the hepatopancreas of shrimp fed diets supplemented with copper. Furthermore, energy metabolism related parameters (ATPase, cytochrome c oxidase, citrate synthase, adenosine 5′-triphosphate) and genes involved in tricarboxylic-acid cycle (cs, aco, idh, ogdh, sdhc, sdhd, fh, mdh) were up-regulated in shrimp fed copper supplemented diets. The present study showed that copper-mediated lipolysis and autophagy can coordinate energy generation, and provided new insight into copper nutrition and the potential beneficial effects of dietary Cu on energy metabolism in crustaceans.

Transcriptomic and physiological analyses of hepatopancreas reveal the key metabolic changes in response to dietary copper level in Pacific white shrimp Litopenaeus vannamei

All living organisms require copper for growth and development, but the gene expression profiles and molecular mechanisms underpinning dietary copper are poorly investigated. Therefore, the present study aimed to determine the potential metabolic changes in response to dietary copper based on analysis of hepatopancreas transcriptome in Litopenaeus vannamei. Three practical diets were formulated to supplement 0 (control diet; CCu) and 40 mg kg−1 inorganic Cu (CuSO4·5H2O; ICu) and copper amino acid chelate (OCu), with analyzed Cu being 12.4, 49.8 and 50.0 mg kg−1, respectively. Shrimp fed ICu and OCu diets had higher percent weight gain and Cu concentration in tissues. Some essential amino acids (lysine, methionine, isoleucine, leucine, valine) and non-essential amino acids (tyrosine, glycine, aspartic acid, proline and serine) in hepatopancreas significantly increased in shrimp fed the copper supplemented diets. Transcriptome analysis indicated a total of 742 and 912 genes were differentially expressed (q < 0.001; log2fold change ≥2) in shrimp fed the ICu and OCu diets, respectively, in comparison to shrimp fed the control diet. Five and eight significantly changed pathways were annotated in the CCu vs. ICu and CCu vs. OCu comparisons, with metabolism the leading category for both. Similarly, the proportion of differentially expressed genes revealed that most were enriched in the category of metabolism. Further analysis revealed that dietary copper mainly affected amino acid and glycerophospholipid metabolism. Moreover, two significantly changed pathways (phagosome and IL-17 signaling pathway) related to the immune system were identified in shrimp fed the OCu diet. The present study analyzing the hepatopancreas transcriptome identified potential roles of dietary copper on amino acid and glycerophospholipid metabolism and provided new insight that will be valuable in future studies to further elucidate the nutritional molecular basis of copper.

Abnormal concentrations of Cu-Co in Haumaniastrum katangense, Haumaniastrum robertii and Aeolanthus biformifolius: contamination or hyperaccumulation?

The Central African Copperbelt of the DR Congo and Zambia hosts more than 30 known Cu-Co hyperaccumulator plant species. These plants can accumulate extraordinarily high concentrations of Cu and Co in their living tissues without showing any signs of toxicity. Haumaniastrum robertii is the most extreme Co hyperaccumulator (able to accumulate up to 1 wt% Co), whereas Aeolanthus biformifolius is the most extreme Cu hyperaccumulator (with up to 1 wt% Cu). The phenomenon of Cu-Co hyperaccumulator plants was studied intensively in the 1970s through to the 1990s, but doubts arose regarding earlier observations due to surficial contamination of plant material with mineral particles. This study set out to determine whether such extraneous contamination could be observed on herbarium specimens of Haumaniastrum robertii and Aeolanthus biformifolius using scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). Further, synchrotron X-ray absorption spectroscopy (XAS) was used to identify the chemical forms of Cu and Co in newly collected Haumaniastrum katangense plant material from the DR Congo. The results show that surficial contamination is not the cause for abnormal Cu-Co concentrations in the plant material, but rather that Cu-Co enrichment is endogenous. The chemical form of Cu and Co (complexation with carboxylic acids) provides additional evidence that genuine hyperaccumulation, and not soil mineral contamination, is responsible for extreme tissue concentrations of Cu and Co in Haumaniastrum katangense.

Assessment of Trace Element Accumulation by Earthworms in an Orchard Soil Remediation Study Using Soil Amendments

This study assessed potential bioaccumulation of various trace elements in grasses and earthworms as a consequence of soil incorporation of organic amendments for in situ remediation of an orchard field soil contaminated with organochlorine and Pb pesticide residues. In this experiment, four organic amendments of differing total organic carbon content and quality (two types of composted manure, composted biosolids, and biochar) were added to a contaminated orchard field soil, planted with two types of grasses, and tested for their ability to reduce bioaccumulation of organochlorine pesticides and metals in earthworms. The experiment was carried out in 4-L soil microcosms in a controlled environment for 90 days. After 45 days of orchardgrass or perennial ryegrass growth, Lumbricus terrestris L. were introduced to the microcosms and exposed to the experimental soils for 45 days before the experiment was ended. Total trace element concentrations in the added organic amendments were below recommended safe levels and their phytoavailablity and earthworm availability remained low during a 90-day bioremediation study. At the end of the experiment, total tissue concentrations of Cu, Cd, Mn, Pb, and Zn in earthworms and grasses were below recommended safe levels. Total concentrations of Pb in test soil were similar to maximum background levels of Pb recorded in soils in the Eastern USA (100 mg kg−1 d.w.) because of previous application of orchard pesticides. Addition of aged dairy manure compost and presence of grasses was effective in reducing the accumulation of soil-derived Pb in earthworms, thus reducing the risk of soil Pb entry into wildlife food chains.

Metal bioavailability and bioaccumulation in the polychaete Nereis (Alitta) virens (Sars): The effects of site-specific sediment characteristics

The present study investigates the relationships between copper (Cu) and zinc (Zn) concentrations in sediment, pore water and their bioaccumulation in the polychaete Nereis (Alitta) virens, as well as the importance of site-specific sediment characteristics in that process. Sediment, pore water and N. virens were sampled from seven sites with different pollution histories along the English Channel coast. Results showed that site-specific metal levels and sediment characteristics were important in determining the bioavailability of metals to worms. Significant correlations were found between Cu in the sediment and in the pore water and between Zn in the pore water and in N. virens. Zn from the pore water was thus more readily available from a dissolved source to N. virens than Cu. Data also showed that metal concentrations in N. virens were lower than those found in other closely related polychaetes, indicating that it may regulate tissue concentrations of Cu and Zn.

Effects of contaminated St. Lucie River saltwater sediments on an amphipod (Ampelisca abdita) and a hard-shell clam (Mercenaria mercenaria).

The St. Lucie estuary (SLE) ecosystem in South Florida has been shown to be contaminated with metals and pesticides. Our earlier studies also showed that aquatic organisms, especially benthic species in the SLE ecosystem, might be potentially at high risk from copper (Cu) exposure. The objectives of this study were to conduct studies with separate groups of organisms exposed to seven field-collected sediment samples from the St. Lucie River according to standard procedures to evaluate toxicity and tissue concentrations of Cu and zinc (Zn). Short term and longer term whole sediment acute toxicity studies were performed with Ampelisca abdita and Mercenaria mercenaria. Analysis of sediment chemical characteristics showed that Cu and Zn are of most concern because their concentrations in 86 % of the sediments were higher than the threshold effect concentrations for Florida sediment quality criteria and the National Oceanic and Atmospheric Administration Screening Quick Reference Tables (SQuiRTs) sediment values. There was no significant effect on survival of the tested organisms. However, increased Cu and Zn concentrations in the test organisms were found. Dry weight of the tested organisms was also inversely related to Cu and Zn concentrations in sediments and organisms. The effects on organism weight and Cu and Zn uptake raise concerns about the organism population dynamics of the ecosystem because benthic organisms are primary food sources in the SLE system and are continuously exposed to Cu- and Zn-contaminated sediments throughout their life cycle. The results of the present study also indicate that Cu and Zn exposures by way of sediment ingestion are important routes of exposure.

Soil acidification increases metal extractability and bioavailability in old orchard soils of Northeast Jiaodong Peninsula in China

The bioavailability of Cu, Zn, Pb and Cd from field-aged orchard soils in a certified fruit plantation area of the Northeast Jiaodong Peninsula in China was assessed using bioassays with earthworms (Eisenia fetida) and chemical assays. Soil acidity increased with increasing fruit cultivation periods with a lowest pH of 4.34. Metals were enriched in topsoils after decades of horticultural cultivation, with highest concentrations of Cu (132 kg−1) and Zn (168 mg kg−1) in old apple orchards and Pb (73 mg kg−1) and Cd (0.57 mg kg−1) in vineyard soil. Earthworm tissue concentrations of Cu and Pb significantly correlated with 0.01 M CaCl2-extractable soil concentrations (R2 = 0.70, p < 0.001 for Cu; R2 = 0.58, p < 0.01 for Pb). Because of the increased bioavailability, regular monitoring of soil conditions in old orchards and vineyards is recommended, and soil metal guidelines need reevaluation to afford appropriate environmental protection under acidifying conditions.

Bioavailability of Copper and Zinc in Mining Soils

The soil-contact exposure pathway can be the main driver of ecological risk assessments. There is currently no standard method to measure bioavailability of metals in soil to ecological receptors, yet the influence of metal bioavailability on toxicity has been known for decades and is a major factor influencing risk to ecological receptors. Bioavailability is to a large degree governed by varying soil characteristics within and among sites, yet ecological screening benchmarks are often derived on a total-concentration basis. We compared a calcium chloride (CaCl2) extraction, cyclodextrin extraction, simulated earthworm gut (SEG) test, earthworm kinetic bioaccumulation test, and metal residues in plant tissues with a battery of invertebrate and toxicity tests using mining soils consisting of high organic-matter content cocontaminated with copper (Cu) and zinc (Zn). Earthworm (Eisenia andrei) tissue concentrations of Cu and Zn were regulated and were not predictive of invertebrate toxicity. All chemical measures of bioavailability correlated with several biological responses; however, CaCl2-extractable Cu and SEG-extractable Cu and Zn best predicted effects to E. andrei. Total Cu concentrations in soil best correlated with effects to plants. Overall, a chemical measure was the best predictor of toxicity to each organism compared with biological measures, although the exact measure was dependent on organism and end point. Chemical-extraction techniques provide relatively quick, inexpensive indicators of essential metal bioavailability compared with biological measures; however, no single measure was indicative of all effects to all organisms.

Macrobenthic community response to copper in Shelter Island Yacht Basin, San Diego Bay, California

We examined Cu contamination effects on macrobenthic communities and Cu concentration in invertebrates within Shelter Island Yacht Basin, San Diego Bay, California. Results indicate that at some sites, Cu in sediment has exceeded a threshold for “self defense” mechanisms and highlight the potential negative impacts on benthic faunal communities where Cu accumulates and persists in sediments. At sites with elevated Cu levels in sediment, macrobenthic communities were not only less diverse but also their total biomass and body size (individual biomass) were reduced compared to sites with lower Cu. Cu concentration in tissue varied between species and within the same species, reflecting differing abilities to “regulate” their body load. The spatial complexity of Cu effects in a small marina such as SIYB emphasizes that sediment-quality criteria based solely on laboratory experiments should be used with caution, as they do not necessarily reflect the condition at the community and ecosystem levels.

Bioaccumulation of copper and toxic effects on feeding, growth, fecundity and development of pond snail Lymnaea luteola L.

We studied the bioaccumulation and the toxic effects of Cu on survival, number of eggs and eggmasses laying, embryo development, growth, and food consumption in an Indian pond snail, Lymnaea luteola L. exposed for 7 weeks. Copper caused loss of chemoreception, locomotion and inhibited food consumption significantly during 7 weeks of exposure. Food consumption in Cu exposed snails significantly decreased and at 56 and 100 μg L −1, snail stopped feeding activity. Mean number of eggmasses or eggs significantly decreased in Cu concentrations during the 7 week study. The percentage hatching decreased in Cu concentrations but there was more than 95% hatched in control in 10–11 days after spawning. Egg development was completely inhibited at 100 μg L −1, while abnormal embryonic development observed at 32 and 56 μg L −1 of Cu. The Cu concentration in tissues increased in Cu treated snails and bioaccumulation factor ranged from 2.3 to 18.7. Snail growth at 5.6 and 10 μg L −1 was reduced by 6.2% and 16.9%, respectively. The study revealed that snail embryos and adults could be used as in vivo test models for ecotoxicological studies. Findings of present study are helpful for advancing water quality guidelines for protecting aquatic biota.

Effect of copper- and zinc-methionine supplementation on bioavailability, mineral status and tissue concentrations of copper and zinc in ewes

The effect of feeding Cu- and Zn-methionine to ewes was studied in a 240d feeding trial. The plasma and tissue Cu and Zn concentrations and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) activity were employed to assess the relative bioavailability from Cu- and Zn-methionine. The macro and micronutrient intake, utilization, plasma mineral status, tissue accumulation of Cu and Zn as well as wool concentration of Cu and Zn were studied in ewes ( n=12) fed a corn-soybean meal based basal diet with 50% more Cu and Zn supplementation over the basal diet either from Cu- and Zn-sulfate (Cu-Sulf+Zn-Sulf group) or Cu- and Zn-methionine (Cu-Meth+Zn-Meth group). The average daily feed intake and body weight gain of ewes did not differ due to dietary supplementation of Cu- and Zn-methionine. However, dry matter intake was comparatively lower and thus resulted in better feed: gain in Cu- and Zn-methionine group as compared to ewes fed Cu- and Zn-sulfate. Supplementation of Cu and Zn over the basal diet either from methionine-chelated or sulfate sources resulted in increased plasma Cu and Zn as well as Cu/Zn-SOD activity on d-30, which indicated a positive correlation between plasma Cu and Zn and Cu/Zn-SOD activity. The gut absorption, liver concentrations of Cu and Zn, and liver Cu/Zn-SOD activity were significantly ( P<0.01) higher in ewes supplemented with Cu- and Zn-methionine compared to Cu- and Zn-sulfate. Periodical analysis of wool samples indicated no significant difference in Cu and Zn content between Cu-and Zn-methionine and Cu- and Zn-sulfate groups. Feeding of Cu and Zn from methionine-chelated source resulted in reduced ( P<0.01) excretion of Cu and Zn in feces indicating their better utilization, and this will have positive implication on environment. The gut absorption values, plasma and liver tissue concentrations of Cu and Zn supported the hypothesis that Cu- and Zn-methionine supplements have better bioavailability compared to Cu- and Zn-sulfate and Cu- and Zn-dependent enzyme (Cu/Zn-SOD) could be used to determine the bioavailability of Cu and Zn.

Evaluating the role of zinc in the occurrence of fibrosis of the skin: A preclinical study

To investigate the possible role of Zn as a trigger for NSF we were using a previously established preclinical model. The depletion of endogenous Zinc ions (Zn) caused by the administration of gadolinium-based contrast agents (GBCAs) has been suggested as a possible pathomechanism for nephrogenic systemic fibrosis (NSF). In the Zn supplementation study, rats were injected with Gadodiamide, Omniscan, and Magnevist with or without Zn supplementation. In the Zn depletion study, animals were kept on a Zn-deficient diet or a special control diet and received injections of Omniscan, OptiMARK, Magnevist, Gadovist, and Gd-EDTA. Gd, Zn, and Cu concentrations in tissue were measured and histology of the skin was performed. As seen in earlier studies, a difference in Gd concentration in the skin was observed following treatment with the different GBCAs. High Gd concentration in the skin correlated with the occurrence of NSF-like skin lesions. We observed no differences in the occurrence of skin lesions between the Zn supplementation and the Zn-deficient groups compared to their respective control groups. We found no significant effect of Zn on the initiation of NSF-like skin lesions. The results further support data from previous studies highlighting the importance of complex stability of the investigated GBCAs.

Aging effect on the mobility and bioavailability of copper in soil

Aging effect on the mobility and bioavailability of copper (Cu) was investigated using a spiked soil with different incubation periods from 3 to 56 d. Wheat was planted and earthworms were cultured separately in the incubated soils. The mobility of Cu in soil was evaluated by a chemical fractionation scheme and the toxicity and bioavailability were assessed by measuring the biomass and Cu concentration in tissues. Results showed that aging had a significant effect on Cu fraction distribution, of which Cu tended to incorporate from the exchangeable into more stable fractions such as the reducible and oxidisable fractions. However, aging had little effect on Cu bioavailability to wheat and earthworm. Comparing the soil being incubated for 3 d and 56 d, Cu concentration in wheat roots decreased from 14.5 to 12.8 mg/kg, and no significant changes in Cu concentration were observed in both wheat shoots and earthworms. The Cu concentration was around 2.0 and 50 mg/kg for wheat shoots and earthworms, respectively, irrespective of soil incubation time. The CaCl2-extractable Cu had a linear relationship with Cu concentration in wheat roots (R2 = 0.65, P < 0.05), but no linear relationship can be found for wheat shoots and earthworms. Biological control may be more crucial for Cu accumulation in organism than the changes in soil Cu fraction caused by aging.

Fine Root Decomposition and Cycling of Cu, Ni, Pb, and Zn at Forest Sites Near Smelters in Sudbury, ON, and Rouyn-Noranda, QU, Canada

ABSTRACT This study determined rates of in situ fine root decomposition and changes in trace metals concentration during decomposition at sites in Sudbury, ON, and Rouyn-Noranda, QU, with elevated or background concentrations of Cu, Ni, Pb, and/or Zn in the soil, and correlated the depth gradients of Cu, Ni, Pb, and Zn for soils and roots at the same sites. Fine roots were extracted from soil cores within root traps several times over 12 months; biomass and metal concentrations were measured. Live roots were collected from 30-cm soil cores, separated into three depths. Elevated soil metal concentrations did not necessarily reduce fine root decomposition, and effects on decomposition were similar to those previously reported for surface foliar litter at the same sites. Decomposing roots at only the high metal sites demonstrated increased metal concentrations with time. Root tissue concentrations of Cu, Ni, and Zn, but not Pb, at lower soil depths were generally higher than expected from soil metal concentrations. This could be explained by reallocation of essential metals, although these metals were likely also more available for uptake at depth due to lower DOC concentrations. This study means that for risk assessment, separate determinations of altered decomposition for roots and leaf litter are likely not necessary for predicting ecosystem effects, a pragmatically useful conclusion given the labor intensity of the fine root studies. This study also suggests that for risk assessment of plant community exposure to metals, prediction of exposure to metals should probably consider soil layers that do not have substantially elevated metal concentrations, as their soil characteristics, or plant processes, may result in unexpected exposure.

Bioaccumulation and Depuration Pattern of Copper in Different Tissues of Mystus vittatus, Related to Various Size Groups

The bioaccumulation pattern of copper (Cu) in gill, liver, kidney, and muscle of different sizes (fingerlings and adult age) of healthy Mystus vittatus when exposed to their respective sublethal concentrations of Cu-water, containing one-third 96-hr LC(50) level (6.20 and 15.95 mg L(-1)) for short-term (120 hr) and one-eighth 96-hr LC(50) level (2.33 and 5.98 mg L(-1)) for long-term experimentation, respectively, has been analyzed. The Cu shows a maximum deposition (p < 0.01) in the liver (82.12 and 70.65 microg/g) followed by gill (74.35 and 63.69 microg/g) and kidney (61.52 and 54.09 microg/g) both in fingerlings and adult fish, respectively, during 28 days of exposure. The lowest deposition of Cu is found to be 0.83 and 0.93 microg/g in fingerlings and 0.79 and 0.86 microg/g in adult muscle tissue during short-term (120 hr) and long-term (28 days) exposure periods, respectively. Comparing the accumulation of Cu on the two size groups at both exposure levels, it is obvious that the fingerlings showed higher Cu concentration in all tissues than those of adult fish. Another equally important finding is that the depuration of Cu by maintaining the bioaccumulated fish (long-term exposed group) of both size groups in quality dechlorinated ground water reveals that there is a significant (p < 0.05) reduction in Cu concentration in different tissues as the day passes. A comparison of the performance of the two size groups in respect of depuration clearly indicates that the fingerlings have taken 24-43 days (gill-kidney), whereas in mature fish it is 21-39 days (gill-kidney) to reach the level of control fish. Among the various tissues in both size groups, gill took the minimum number of days for complete recovery, whereas the muscle tissue did not significantly eliminate Cu even after 30 days of depuration. These data constitute a reference for future studies on the evolution of Cu accumulation and elimination tendency in relation to different size groups of fish in the ecotoxicological testing scheme for hazard assessment.

Testing the use of juvenile Salmo trutta L. as biomonitors of heavy metal pollution in freshwater

Individual specimens of Salmo trutta were captured, from four sampling sites in Galician rivers (NW Spain) affected by different types of contamination: diffuse urban waste, run-off from an unrestored dump at a copper mine and waste from a fish farm. The ages of the captured trouts were established and only those belonging to the 1+ age class were selected for study. The liver and kidney were removed from each fish and analysed to determine the tissue concentrations of Cu, Fe and Zn. The results obtained showed that: (i) the use of 1+ individuals allowed differentiation of contamination scenarios on the basis of the tissue concentrations of metal; (ii) the use of 1+ individuals allowed standardization of the time of exposure, which was sufficiently long for differential uptake to have taken place; (iii) liver tissue provided the best results as, less effort was required than for processing kidney tissue, and significant differences between sampling sites were detected because the intrapopulational variability in metal levels was lower than for kidney, and (iv) the levels of elements detected were not affected by basal tissue concentrations or residual concentrations due to past contamination, which older trouts may have been exposed to. In addition, the use of 1+ trout may provide better results in annual environmental sampling surveys.

Comparing copper requirements of canola, albus lupin, durum wheat and spring wheat grown on alkaline soils

The copper (Cu) requirements of spring wheat (Triticum aestivum L.), the major crop for alkaline soils in south-western Australia, is well known. The Cu requirements of canola (Brassica napus L.), albus lupin (Lupinus albus L.) and durum wheat (Triticum durum L.), alternative crops for these soils, are not known. A glasshouse experiment, using 2 alkaline soils from south-western Australia, compared the yield and Cu content response to applications of Cu to canola, albus lupin, durum wheat and spring wheat. The Cu was applied either just before 45-days incubation in moist soil at 20°C (incubated Cu), or just before sowing after the incubation treatment (current Cu). Comparative Cu requirements were determined from yields of 45-day-old dried shoots for: (i) Cu already present in the soil (indigenous soil Cu); (ii) the amount of applied Cu required to produce the same percentage of the maximum (relative) yield of dried shoots; and (iii) the Cu content of dried shoots (Cu concentration multiplied by yield of dried shoots). The concentration of Cu in youngest tissue and in dried rest of shoots was used to determine critical Cu concentrations in tissue. Albus lupin used indigenous Cu so effectively it only showed a 10% yield increase to applied Cu. Canola used indigenous Cu more effectively than durum wheat, which was followed by spring wheat. Relative to spring wheat, durum wheat was about 15% less effective at using incubated and current Cu to produce dried shoots and canola was about 47% more effective. Therefore, to produce the same percentage of the maximum (relative) yield as spring wheat, durum wheat required about 15% more incubated and current Cu and canola required about 50% less Cu. As determined using Cu content in shoots, canola and durum wheat were about 45% more effective than spring wheat at increasing Cu content in shoots and albus lupin was about 80% more effective. Evidently, all 3 species took up more copper than spring wheat. Durum wheat did not use this Cu to produce more shoot yield than spring wheat, whereas canola did. The critical Cu concentration in the youngest tissue (mg Cu/kg), associated with 90% of the relative yield, was: 1.5 for spring wheat; 1.7 for durum wheat; 1.0 for albus lupin; and 2.2 for canola. Corresponding values (mg Cu/kg) for rest of dried shoots were: 2.5 for spring wheat; 3.2 for durum wheat; 1.3 for albus lupin; and 2.7 for canola.

Application of trichloroacetic acid (TCA) to extraction of soft body for the determination of tissue Cd, Cu, Pb and Zn in the prosobranch Hydrobia ulvae (Pennant)

The application of trichloroacetic acid (TCA) as a shell extractant for preparation of soft body parts with reference to tissue metal concentrations (Cd, Cu, Pb, Zn) in shellfish has been evaluated on the example of the mud snail Hydrobia ulvae, a small marine prosobranch densely present in rocky and soft-bottom habitats of the eastern Atlantic. A solution of 0.1 M TCA was tested on individuals treated according to two different protocols: (1) thawed after freezing (“non-dried”) and (2) thawed and air-dried to a constant weight (“dried”). Two points were investigated in detail to improve the method: individual soft tissue dry weight and tissue metal concentration following a standard digestion method. In both instances, the results were compared with those from manually dissected snails. Conditions for total shell decalcification of 60 individuals (3–4 mm long) were 5.5 h in 20 ml of 0.1 M TCA. No differences in individual soft tissue weight were observed between the treatments, indicating good efficiency of the TCA extraction with respect to weight of soft body parts. In contrast, tissue metal concentrations varied among treatments. The TCA extraction of the dried animals had a good recovery for Cd, most likely due to the lower solubility of Cd vital cellular components (proteins and mineral concretions) from the dried tissue. Satisfactory recoveries of the tissue concentrations of Cu and Pb were obtained for the non-dried individuals. This might be related to the specific distribution of metals in the organism (namely in the digestive glands and gonads) and their different chemical reactivity with TCA after the tissue was dried. Limited susceptibility of Zn-bearing protein bindings to complexing with TCA also accounts for significantly lower concentrations of Zn in the mud snail’s soft tissue that was extracted. The 0.1 M TCA solution is therefore recommended for extraction of the shells of Hydrobia ulvae for tissue determination of Cd, Cu and Pb; however the treatment protocol does affect metal recovery and thus a consistent procedure should be followed. The extracted metals from the soft tissues and shells of the mud snails (on the basis of both metal concentrations and contents) were ranked in order of increasing contribution of soft body parts to the total (shell + tissue): Pb < Cd < Zn < Cu.

Comparing Copper Requirements of Faba Bean, Chickpea, and Lentil with Spring Wheat

The copper (Cu) requirement of four crop species was measured in a glasshouse experiment using yield of dried shoots and Cu content (Cu concentration multiplied by yield of dried shoots) of 62 day old plants grown in two different alkaline soils. The species compared were faba bean (Vicia faba L. cv. Fiord), chickpea (Cicer arietinum L. cv. Tyson), lentil (Lens culinaris Medik cv. Digger), and spring wheat (Triticum aestivum L. cv. Stretton). The comparative Cu requirement of the species was determined from yields of dried shoots when no Cu fertilizer was applied, the amount of applied Cu required to produce the same percentage of the maximum (relative) yield of dried shoots, and the Cu content of dried shoots. The concentration of Cu in youngest tissue and in dried shoots was used to determine critical concentrations of Cu in tissue associated with 90% of the maximum yield. Faba bean used indigenous soil Cu more effectively than wheat, followed by chickpea and then lentil. As measured using both shoot yield and Cu content in shoots, the Cu requirement was lowest for faba bean, and increased in the order faba bean < wheat < chickpea < lentil. Copper concentration in dried youngest tissue and in dried shoots increased with an increase in the amount of added Cu. The critical Cu concentration in the youngest tissue was (mg Cu/kg): 4.6 for lentil, 2.6 for chickpea, 1.5 for wheat, and 2.8 for faba bean; corresponding values for dried shoots (mg Cu/kg) were 6.3 for lentil, 3.3 for chickpea, 2.8 for wheat, and 3.0 for faba bean.

Toxicity, growth and accumulation relationships of copper, lead and zinc in the grey mangrove Avicennia marina (Forsk.) Vierh

The effects of three heavy metals Copper (Cu), lead (Pb) and zinc (Zn), and the interaction of an essential (Zn) and non-essential (Pb) metal on germination, growth, and accumulation of metals in the grey mangrove, Avicennia marina (Forsk.) Vierh var. australasica (Walp.) Moldenke, were studied under laboratory conditions. Avicennia marina was found to be highly tolerant to the metals applied. Copper was accumulated in root tissue in a linear relationship at lower sediment concentrations, but at concentrations of 200 μg/g and higher, no further increases in root Cu levels occurred. Translocation of Cu from the root to leaf tissue was low, yet revealed similar accumulation patterns as root tissue. Significant reductions in seedling height leaf number and area were found with significant increases in Cu concentrations in tissues at 100 μg/g sediment Cu. At Cu sediment levels of 400 μg/g, a decrease in total biomass and root growth inhibition was observed. Emergence was retarded with increasing copper concentration, with 800 μg/g sediment Cu resulting in a total inhibition of emergence. The LC 50 for emergence and EC 50 for biomass was 566 and 380 μg/g Cu respectively. Lead accumulation in root tissue was lower that other metals, yet increased in a dose dependant fashion across the sediment Pb concentration range examined. Lead was excluded from leaf tissue at Pb sediment concentrations up to 400 μg/g, above which limited transport of Pb occurred. Little negative effects on growth were observed due to the low accumulation of Pb. Zinc uptake was high, and was accumulated in a linear fashion in root tissue across the sediment Zn concentration range applied. Zinc translocation to leaf tissue exhibited a dose dependant relationship with both root and sediment Zn levels. Emergence decreased with increasing sediment Zn concentrations, with 1000 μg/g sediment Zn showing 100% mortality. Significant reductions in seedling height, leaf number, area, biomass and root growth inhibition were found at concentrations of 500 μg/g sediment Zn. The LC 50 for emergence and EC 50 for biomass was 580 and 392 μg/g Zn respectively. Lead and Zn in combination resulted in an increased accumulation of both metals in leaf tissue and increased toxicity than individual metals alone, and is the first noted occurrence of a Pb and Zn additive response in angiosperms. Possible mechanisms of accumulation and toxicity are discussed.