Effects of heavy metal accumulation on some reproductive characters in Armadillidium granulatum Brandt (Crustacea, Isopoda, Oniscidea)

In silico identification and expression analyses of peroxidases in Tenebrio molitor

Human advancements in agriculture, urbanization, and industrialization have led to various forms of environmental pollution, including heavy metal pollution. Insects, as highly adaptable organisms, can survive under various environmental stresses, which induce oxidative damage and impair antioxidant systems. To investigate the peroxidase (POX) family in Tenebrio molitor, we characterized two POXs, namely TmPOX-iso1 and TmPOX-iso2. The full-length cDNA sequences of TmPox-iso1 and TmPox-iso2 respectively consisted of an open reading frame of 1815 bp encoding 605 amino acids and an open reading frame of 2229 bp encoding 743 amino acids. TmPOX-iso1 and TmPOX-iso2 homologs were found in five distinct insect orders. In the phylogenetic tree analysis, TmPOX-iso1 was clustered with the predicted POX protein of T. castaneum, and TmPOX-iso2 was clustered with the POX precursor protein of T. castaneum. During development, the highest expression level of TmPox-iso1 was observed in the pre-pupal stage, while that of TmPox-iso2 expression were observed in the pre-pupal and 4-day pupal stages. TmPox-iso1 was primarily expressed in the early and late larval gut, while TmPox-iso2 mRNA expression was higher in the fat bodies and Malpighian tubules. In response to cadmium chloride treatment, TmPox-iso1 expression increased at 3 hours and then declined until 24 hours, while in the zinc chloride-treated group, TmPox-iso1 expression peaked 24 hours after the treatment. Both treated groups showed increases in TmPox-iso2 expression 24 hours after the treatments.

Malic acid inhibits accumulation of cadmium, lead, nickel and chromium by down-regulation of OsCESA and up-regulation of OsGLR3 in rice plant

Malic acid (MA) plays an important role in plant tolerance to toxic metals, but its effect in restricting the transport of harmful metals remains unclear. In this study, japonica rice NPB and its fragile-culm mutant fc8 with low cellulose and thin cell wall were used to investigate the influence of MA on the accumulation of 4 toxic elements (Cd, Pb, Ni, and Cr) and 8 essential elements (K, Mg, Ca, Fe, Mn, Zn, Cu and Mo) in rice. The results showed that fc8 accumulated less toxic elements but more Ca and glutamate in grains and vegetative organs than NPB. After foliar application with MA at rice anthesis stage, the content of Cd, Pb, Ni significantly decreased by 27.9-41.0%, while those of Ca and glutamate significantly increased in both NPB and fc8. Therefore, the ratios between Cd and Ca in grains of NPB (3.4‰) and fc8 (1.5‰) were greatly higher than that in grains of NPB + MA (1.1‰) and fc8+MA (0.8‰) treatments. Meanwhile, the expression of OsCEAS4,7,8,9 for the cellulose synthesis in secondary cell walls were down-regulated and cellulose content in vegetative organs of NPB and fc8 decreased by 16.7-21.1%. However, MA application significantly up-regulated the expression of GLR genes (OsGLR3.1-3.5) and raised the activity of glutamic-oxalacetic transaminease for glutamate synthesis in NPB and fc8. These results indicate that hazard risks of toxic elements in foods can be efficiently reduced through regulating cellulose biosynthesis and GLR channels in plant by combining genetic modification in vivo and malic acid application in vitro.

The metabolism and detoxification effects of lead exposure on Aleurolyphus ovatus (Acari: Acaridae) via transcriptome analysis

Aleurolyphus ovatus Troupeau is one of the most predominant species of the Acaridae family worldwide. Recent reports have demonstrated that the accumulation of lead in stored grains and dietary items exceeds the required standards. However, the molecular mechanism of heavy metal stress on mites has not been reported. To understand the mechanism underlying the heavy metal response of A. ovatus, comparative transcriptome analysis was performed in this study using an Illumina high throughput mRNA sequencing (RNA-seq) platform. A. ovatus was fed on artificial diets containing two different concentrations of lead, namely, a low concentration of 12.5 mg/kg (LAO) and a high concentration of 100 mg/kg (HAO), while the mites in the control (NAO) group were not exposed to lead. A total of 44,362 unigenes, with an average length of 1547 bp, were identified. Of these, 996 unigenes were successfully annotated in seven functional databases. The number of differentially expressed genes (DEGs) in A. ovatus under different lead concentrations was compared. In NAO versus LAO group, including 310 up-regulated and 1580 down-regulated DEGs. In NAO versus HAO group, including 3928 up-regulated and 1761 down-regulated DEGs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment indicated that detoxification enzyme genes were significantly expressed in pathways, such as cytochrome P450 foreign body metabolism, glutathione metabolism and drug metabolism-cytochrome pathway. The results of gene annotation and quantitative real-time PCR showed that high concentration of lead significantly stimulated the expression of metabolic detoxification enzyme genes such as glutathione S transferase (GST) and superoxide dismutase (SOD), while low concentration inhibited their expression. This study will provide a basis for the molecular mechanism of A. ovatus in response to heavy metal lead stimulation in stored grain.

Artificial intelligence-based approaches to evaluate and optimize phytoremediation potential of in vitro regenerated aquatic macrophyte Ceratophyllum demersum L

Water bodies or aquatic ecosystem are susceptible to heavy metal accumulation and can adversely affect the environment and human health especially in underdeveloped nations. Phytoremediation techniques of water bodies using aquatic plants or macrophytes are well established and are recognized as eco-friendly world over. Phytoremediation of heavy metals and other pollutants in aquatic environments can be achieved by using Ceratophyllum demersum L. - a well-known floating macrophyte. In vitro regenerated plants of C. demersum (7.5 g/L) were exposed to 24, 72, and 120 h to 0, 0.5, 1.0, 2.0, and 4.0 mg/L of cadmium (CdSO₄·8H₂O) in water. Results revealed significantly different relationship in terms of Cd in water, Cd uptake by plants, bioconcentration factor (BCF), and Cd removal (%) from water. The study showed that Cd uptake by plants and BCF values increased significantly with exposure time. The highest BCF value (3776.50) was recorded for plant samples exposed to 2 mg/L Cd for 72 h. Application of all Cd concentrations and various exposure duration yielded Cd removal (%) between the ranges of 93.8 and 98.7%. These results were predicted through artificial intelligence-based models, namely, random forest (RF), extreme gradient boosting (XGBoost), and multilayer perceptron (MLP). The tested models predicted the results accurately, and the attained results were further validated via three different performance metrics. The optimal regression coefficient (R²) for the models was recorded as 0.7970 (Cd water, mg/L), 0.9661 (Cd plants, mg/kg), 0.9797 bioconcentration factor (BCF), and 0.9996 (Cd removal, %), respectively. These achieved results suggest that in vitro regenerated C. demersum can be efficaciously used for phytoremediation of Cd-contaminated aquatic environments. Likewise, the proposed modeling of phytoremediation studies can further be employed more comprehensively in future studies aimed at data prediction and optimization.

The health risk for consumers under heavy metal scenarios: Reduce bioaccumulation of Cd in estuary mud crab (Scylla paramamosain) through the antagonism of Se

Heavy metal pollution has gained increasing attention over past years, and notably, cadmium (Cd) is a non-essential heavy metal that can be toxic to human and wildlife. Furthermore, selenium (Se) is a component of the selenoproteins and influences the toxicity of Cd in different organisms, and protect organisms as a kind of heavy metal antagonist. This study exposed mud crab to 5.0 mg/L Cd for 28 days, and investigated whether different concentrations (0.1, 0.2, 0.3 mg/kg) of selenite (Na₂SeO₃) or selenomethionine (SeMet) affect the bioaccumulation of Cd, serum biochemical index, antioxidant and stress-response genes of S. paramamosain. The results showed that the Cd concentration in Cd group was significantly higher than the organic or inorganic Se group. Serum biochemical index demonstrated that Se might relieve the damage or dysfunction of hepatopancreas caused by both Cd accumulation and toxicity. Furthermore, Se improved CAT, GPx T-AOC and SOD activity, and decreased MDA concentrations and the lipid peroxidation levels, antagonistic to Cd. Then, this study analyzed the expression of 26 stress-related genes, the results indicated that the inorganic and organic Se might reduce the damage of cell and the toxicity of heavy metals in the hepatopancreas after Cd exposure. Therefore, this study indicated that Se might alleviate Cd toxicity via the different antioxidative mechanisms, and increased the understanding of environmental toxins on estuary crustaceans.

Heavy metals uptake and translocation of typical wetland plants and their ecological effects on the coastal soil of a contaminated bay in Northeast China

Heavy metal pollution in coastal zone is a global environment problem concerning the international society. As an eco-friendly and economical method, phytoremediation is a promising strategy for improving heavy metal pollution in coastal soil. In order to alleviate the ecological risk of heavy metal pollution in Jinzhou Bay, a typical and important heavy industrial area in China, three local wetland plants (Scirpus validus, Typha orientalis and Phragmites australis) were selected and planted in the field. The plants showed strong tolerance of high concentrations of heavy metals. Stressed by the heavy metals, the root weight of S. validus and P. australis increased 114.74% and 49.91%, respectively. The concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, As, Hg) accumulated in the plant roots were 4-60 times higher than that in plant shoots. The SEM analysis found that abundant heavy metals were adhered to the root surface closely. Bioconcentration factor of heavy metals on the plant roots were 0.08-0.89 (except Cr, Ni), while the translocation factor from roots to above ground of plants were 0.02-0.27. Furthermore, the wetland plants improved the regional ecological environment quality. The concentrations of heavy metals in the rhizosphere soil decreased significantly. Compared with the bulk soil, the potential ecological risk index in the rhizosphere soil reduced 26.51%-69.14%. Moreover, the microbial diversity in rhizosphere soil increased significantly, and the abundances of Proteobacteria and Bacteroidetes also increased in rhizosphere soil. Pearson correlations indicated that Hg, As, Ni and Cr were negatively correlated with Proteobacteria (p < 0.05), and Cu was significantly negative correlated with Bacteroidetes (p < 0.05). The results support that using suitable local plants is a promising approach for repairing heavy metal contaminated costal soil, not only because it can improve the regional ecological environment quality, but also because it can enhance the landscape value of coastal zone.

Physiological and histological effects of cadmium, lead, and combined on Artemia franciscana

This study analyzed the effects of cadmium (Cd) and lead (Pb) on growth, sexual couples, and histological structures of Artemia franciscana exposed to individual concentrations of these metals and combined. No histological effects were observed at tissue level in digestive, respiratory, nervous, and reproductive systems (i.e., necrosis, loss of regular structure) in individual and mixed applications on A. franciscana for 20 days of exposure. No significant differences (p > 0.05) were determined in final size and growth rate among the organisms exposed to Cd and those of control. For Pb, only the final size (3.59 ± 0.59 mm) of organisms exposed to the highest concentration was significantly lower (p < 0.05) than those of the control (4.53 ± 0.34 mm) group, whereas for the combined experiment, no significant differences (p > 0.05) were observed in final size and growth rate. At all Cd concentrations, mean sexual couples were significantly lower (p < 0.05) than those of the control, as well as for Pb. For the combined experiment (8 μg/L of Cd + 8 μg/L of Pb), sexual couples were not observed, indicating synergism and negative reproduction effects. The results showed that Cd and Pb aquatic environmental regulations (as the Criterion of Continuous Concentration) proposed by the US Environmental Protection Agency (EPA) should include their interactions with other metals.

A nationwide survey of trace metals and Zn isotopic signatures in mussels (Mytilus edulis) and oysters (Crassostrea gigas) from the coast of South Korea

Thirteen trace metals and Zn isotopic signatures were investigated in mussels and oysters collected from the coast of South Korea to evaluate their bioavailability in bivalve mollusks. The average Cu, Zn, and Cd concentrations were 2.6-17.7 times higher in oysters than mussels, and high biota sediment accumulation factors (>30) were observed for these metals in oysters. Except for Pb in mussels, most metals had no correlation with total sediment concentrations. In oysters, Fe, V, Cu, Zn, Sn, and Pb concentrations were significantly correlated with sediments. The average values of δ⁶⁶Zn_IRMM3702 in mussels, oyster, and sediments were +0.09‰, +0.12‰, and -0.06‰, respectively. Soft tissues of mussels and oysters with high Zn concentrations tended to contain lighter Zn isotopes. The results indicate that oysters are a better biomonitoring organism for metal contamination than mussels and can be used in the monitoring and management of coastal environments and ecosystems.

The concentration of the potentially toxic elements (PTEs) in the muscle of fishes collected from Caspian Sea: A health risk assessment study

In the present study, the concentration of (potentially toxic element) PTEs in the five fish species from the Caspian Sea (from five coastal areas) was measured and compared. The target hazard quotient (THQ) and total THQ (TTHQ) were calculated using Monte Carlo simulations to determine the non-carcinogenic risk in both children and adults consumers. The highest concentration of PTEs was associated with chromium (Cr) measured in Cyprinus carpio, sampled from Bandar Anzali (1.56 ± 0.14 μg/g dw), and the minimum PTEs level was nickel (Ni) in Vimba from Astara (0.02 ± 0.01 μg/g d w). The rank order for PTEs based on THQ was mercury (Hg) > cadmium (Cd) > lead (Pb)> Ni > tin (Sn) > Total Cr. For adults, the fishes rank order based on TTHQ was: Cyprinus carpio (3.268) > Chelon saliens (2.89) > Rutilus frisii kutum kanesky (2.28) > Oncorhynchus mykis (1.39) > Vimba (0.25); and for children was Cyprinus carpio (15.25) > Chelon saliens (13.47) > Rutilus frisii kutum kanesky (10.63) > Oncorhynchus mykis (6.48) > Vimba (1.16). Overall this study showed that the levels of PTEs in investigated fish species had a potential non-carcinogenic risk for both children and adults (TTHQ>1).

Characterization of cadmium-responsive transcription factors in wolf spider Pardosa pseudoannulata

Transcription factors (TFs) act on the regulation of gene expression, which is prevalent in all organisms, and their characterization may provide important clues for understanding the regulatory mechanism of gene expression. In this research, inhibited growth (delayed developmental time and decreased body weight) and increased activities of antioxidant enzymes (peroxidase, superoxide dismutase, and catalase) were recorded in Pardosa pseudoannulata in response to cadmium burden. Expression profiles of TFs were analyzed based on the transcriptome profiling of P. pseudoannulata, and 1711 TFs genes were differentially expressed with 995 up-regulated and 716 down-regulated. Most of the differentially expressed TFs belonged to zf-C2H2, ZBTB, Homeobox, and bHLH families. Interestingly, hub genes smads, TCF7L2, EGR1, and GATA5 were identified to be the candidate Cd-responsive TFs related to growth of spider. The expression level of Sod2 (superoxide dismutase) was regulated by the up-regulated TF foxo3, implying its important role in the antioxidant defense of spider. Moreover, sequence analysis demonstrated that smads and foxo3 were conserved among spiders and insects. This study revealed for the first time the role of TFs in molecular response of P. pseudoannulata to Cd stress, providing the basis for the protection of tarantula under Cd stress.

Protection of Siganus oramin, rabbitfish, from heavy metal toxicity by the selenium-enriched seaweed Gracilaria lemaneiformis

Seaweed is an inherently important entity in marine ecosystems. It is not only consumed by aquatic animals but also improves environmental quality in the mariculture. Seaweed is also part of the diet of human beings. The purpose of the present study was to evaluate the antagonism of selenium (Se)-enriched Gracilaria lemaneiformis against heavy metals, specifically, the potential of dietary Se-enriched Gracilaria to protect against heavy metal toxicity in rabbitfish (Siganus oramin). Growth rate, heavy metal (Se, Cd, Pb, Cu, Zn and Cr) concentrations, malondialdehyde (MDA), metallothionein (MT), and the activity of the antioxidants, glutathione peroxidase (GPX), catalase (CAT) and superoxide dismutase (SOD) were all assessed. The results showed that the total organic and inorganic Se concentration for the 250 mg L^-1 Se-enriched Gracilaria was significantly higher than those of the 50 and 10 mg L^-1 treatments after 3 days of enrichment. The mean total Se concentrations in Gracilaria were 42.5 μg g^-1 in the 250 mg L^-1 treatment, 13.5 μg g^-1 in the 50 mg L^-1 treatment and 2.5 μg g^-1 in the 10 mg L^-1 treatment, respectively. Organic Se accounts for 80-82% of total Se in Se-enriched Gracilaria. The Se concentration of rabbitfish fed Se-enriched Gracilaria was significantly higher than control. Furthermore, Se increased Cu and Zn absorption, and enhanced MT generation, and improved GPX, CAT, and SOD antioxidant activity, and decreased MDA concentrations and lipid peroxidation levels, all antagonistic to Cd, Pb and Cr. The effects of Se-enriched Gracilaria on waterborne Cd, Pb and Cr-induced toxicity occurred via both enzymatic and non-enzymatic antioxidative mechanisms in rabbitfish. Selenium had synergistic effects on Zn and Cu in rabbitfish. For the 50 mg L^-1 Se-enriched Gracilaria treatment, the Se, Cu, Zn, and antagonistic Cd, Pb, Cr, and the antioxidant enzymes CAT, SOD, GPX activities, and MT concentrations in rabbitfish were higher than that with the 250 mg L^-1 and 10 mg L^-1 Se-enriched Gracilaria treatments. The 50 mg L^-1 Se treatment of Gracilaria was deemed to be the optimum concentration to promote growth of rabbitfish. Therefore, the obtained results suggest Se-enriched Gracilaria can antagonize heavy metal toxicity, and is an advisable Se supplement to improve the edible safety of cultured animals.

Compartmentation and effects of lead (Pb) in the collembolan, Folsomia candida

The impact of soil lead (Pb) pollution on survival, growth, and reproduction of the collembolan, Folsomia candida, and Pb compartmentation in its gut and remaining body parts were studied by exposing animals to laboratory-spiked soil. The survival, growth, and reproduction of F. candida were significantly reduced by increasing soil Pb concentration. The LC₅₀ values of survival based on total and CaCl₂-extractable Pb concentration in soil were 2562 mg kg^-1 and 351 mg kg^-1, respectively. The EC₅₀ values of reproduction were 1244 mg kg^-1 and 48 mg kg^-1, respectively. The Pb concentration in whole body, gut, and remaining body parts was significantly increased with the increase of soil Pb concentration and followed an exponential increase when the soil Pb concentration was equal to or above a threshold (1000 mg kg^-1 for whole body and remaining body part, 500 mg kg^-1 for gut). Below this threshold, these relationships were linear. The Pb concentration in the gut was higher than whole body and remaining body part of F. candida, and the threshold of internal Pb concentration at which F. candida can compensate was in the range 7-13 mg Pb kg^-1 dry animal (corresponding to soil Pb concentration 500-1000 mg Pb kg^-1 dry soil). The results indicate that reproduction of F. candida was a more sensitive indicator of lead toxicity than survival and growth. Pb was mainly accumulated in the gut of F. candida. We discuss the internal Pb concentration as an indicator of adverse effects in the risk assessment of soil Pb pollution.

The influence of processing and clarifier agents on the concentrations of potentially toxic elements (PTEs) in pekmez (a grape molasses-like syrup)

The changes in some potentially toxic elements (PTEs) including lead (Pb), cadmium (Cd), arsenic (As), iron (Fe), zinc (Zn), and copper (Cu) during pekmez (grape molasses-like syrup) processing and the utilization of various types of clarifiers (white soil, bentonite, and gelatin) in two levels (1.5 and 3% w/w) were analyzed. The average concentrations of Pb, Cd, As, Fe, Zn, and Cu in grape samples were measured as 0.055 ± 0.005, 0.030 ± 0.002, 0.044 ± 0.002, 2.882 ± 0.013, 2.372 ± 0.088, and 1.194 ± 0.01 μg g^-1. During pekmez production, the range of changes in Pb, Cd, As, Fe, Zn, and Cu was -43.38% to 40.25%, -55.49% to 0.23%, -76.15% to 1.80%, -74.15% to 58.47%, -40.55% to -18.12%, and -83.16% to -21.39%, respectively. The effect of the clarification process on the PTEs depended on the type and concentration of both PTE and clarifier agent used while the incorporation of gelatin resulted in a significant reduction in all of PT. Graphical abstract.

Health risk assessment of heavy metals in cosmetic products sold in Iran: the Monte Carlo simulation

Cosmetics can contain harmful compounds such as heavy metals. Several metals have a cumulative effect on the body, especially fatty tissues, and may have different health effects on the human body over the long term. Therefore, the main objective of this study was to assess the health risks of heavy metals in cosmetics in Iran. Also, in this study, Monte Carlo simulation was used to investigate uncertainties. In this study, heavy metals data of cosmetics were extracted from studies carried out at intervals 2010-2018. International and Iranian databases such as Google Scholar, Web of Science, Springer, Science Direct, PubMed, Scopus, Irandoc, Magiran, Scientific Information Database (SID), and Information Institute for Scientific (ISC) were searched for this purpose. In this study, the index of the Margin of Safety was calculated to determine the risk of human contact with metallic impurities in cosmetic products used by humans. In the selected period, 11 studies were conducted on the measurement of heavy metals in cosmetics in Iran. In these studies, cosmetics such as eye shadow, eye pencil, powder, cream, and lipstick were studied. The Margin of Safety (MoS) values calculated for different metals were higher than the established safe standard by WHO. The highest and lowest amount of systemic exposure dosage in all types of cosmetic investigated (lipstick, cream, eye pencil, face powder, and eye shadow) was related to Fe and Hg. The mean hazardous quotient (HQ) for Cd, Cr, Ni, Cu, Mn, Zn, Pb, and Hg was 1.05E-03, 1.03E-01, 7.95E-03, 2.59E-03, 1.05E-03, 4.98E-03, 7.22E-04, 1.85E-01, and 1.35E-05, respectively. The highest HQ (6.10E-01) was found for Pb, which was observed in the cream.

The induced damage in the hepatopancreas of Orchestia species after exposure to a mixture of Cu/Zn-An ultrastructural study

The hepatopancreas of crustaceans species has been recognized as an essential target organ to assess trace elements' effects. Due to its dynamic and capability of detoxifying trace metal, this organ often indicates distinct pathological disturbances. In the present work, we intend to evaluate the bioaccumulation of trace metal in three Orchestia species (Orchestia montagui, Orchestia gammarellus, and Orchestia mediterranea) living in symmetry in the banks of Bizerte lagoon (37°13'8″N 09°55'1″E) after their exposure during 14 days to a mixture of copper and zinc, and to highlight the effect of these metals on their hepatopancreas ultrastructure using transmission electron microscopy. At the end of the experiment, results showed that the mortality and the body mass varied according to the used nominal concentrations. Significant alterations were noted in all the treatment groups. The degree of these alterations depends on the used concentration, and they are represented especially by the cells remoteness and the border lyses, the reduction of the nuclear volume, the increase in the cytoplasm density with the presence of trace metal in the nucleus as well as in the vacuole, the disorganization and the destruction of microvilli, the condensation of the majority of cellular organelles and mitochondria swelling. Through this study, Orchestia genus could be an attractive candidate for the biochemical study of trace metal toxicity in Tunisian wetlands.

Effects of Heavy Metals Artificial Contamination on Porcellio laevis (Latreille, 1804) (Crustacea: Isopoda: Oniscidea)

This study aimed at determining the competition of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) on their assimilation, on the food consumption and the growth of terrestrial isopod Porcellio laevis. Individuals were exposed to artificially contaminated litter of Quercus for 4 weeks and were weekly weighed. At the end of the experiment, the concentration of Cd, Pb, Zn and Cu in individuals were measured by atomic absorption spectrometry. Biological parameters such as growth, and bioaccumulation factor (BAF) were calculated and results from the various treatments were compared. Depending on metals, weight loss or gain were recorded for isopods during the four weeks of exposure. A weight loss was measured on individuals exposed to Cd-contaminated litter whereas a weight gain was highlighted for those exposed to the Zn-contaminated litter. BAF values revealed that P. laevis was macroconcentrator of Zn and Cu and deconcentrator of Cd and Pb.

Expression and functional analysis of cytochrome P450 genes in the wolf spider Pardosa pseudoannulata under cadmium stress

Cytochrome P450 enzymes (CYPs), encoded by Halloween genes, mediate the biosynthesis of molting hormone, ecdysteroids, in arthropods. In this report, the effect of heavy metal cadmium (Cd) stress on the expression of cytochrome P450 genes in the wolf spider Pardosa pseudoannulata was analyzed. The results showed the expression levels of genes encoding for Cd transporters including ABC transporters, zinc transporters, calcium channel proteins and calcium binding proteins were inhibited or induced by Cd stress. In addition, the increase in metallothionein (MT) content and glutathione peroxidase (GPX) activity and decrease in total acetylcholine esterase (AChE) activity were also detected. Apparently, these detoxification methods did not completely protect the spider from the cytotoxicity of Cd stress. Increased mortality of P. pseudoannulata was observed when they were under Cd tress. In total 569 CYP genes belonging to 62 CYP subfamilies were obtained from P. pseudoannulata RNA-seq databases. BlaxtX analysis showed that 150, 161, 11, and 40 CYP genes were similar to the genes dib, phm, sad and shd, respectively, which are thought to catalyze the biosynthesis of ecdysteroids. Gene expression analysis suggested that 25 dib encoding genes, 27 phm encoding genes, 2 sad encoding genes, and 6 shd encoding genes were differentially expressed in TS2 vs. S2 comparison (Cd-treated 2nd instar spider vs. 2nd instar spider), respectively. There were 70 dib, 70 phm and 19 shd encoding genes either upregulated or downregulated, while 3 sad encoding genes were upregulated in TS5 vs. S5 (Cd-treated 5nd instar spider vs. 5nd instar spider). Genes related to heme binding and essential for activating the CYPs were also differentially expressed. Expression levels of cuticle related genes were significant differentially expressed, implying the changes in activities of chitin synthases and chitinase. Therefore we assume that unsuccessful molting process may occur on P. pseudoannulata due to influenced ecdysteroids levels, thus increasing mortality of spider.

Ecotoxicological effects of trace element contamination in talitrid amphipod Orchestia montagui Audouin, 1826

This study deals with the evaluation of trace element bioaccumulation and histological alterations in the hepatopancreas of the supralittoral amphipod Orchestia montagui Audouin, 1826 due to the exposure to cadmium, copper, and zinc. Orchestia montagui individuals were maintained during 14 days in soils contaminated with different trace elements namely cadmium, copper, and zinc; a control was also prepared. Our results show that the mortality and the body mass vary according to the metal and the nominal concentration used. In general, the mortality increases from the seventh day. However, the body mass shows a decrease with cadmium exposure and an increase with copper and zinc exposures. Furthermore, the concentration factor highlights that this species is considered a macroconcentrator for copper and zinc. The hepatopancreas of unexposed and exposed animals were compared to detect histological changes. Our results show significant alterations in the hepatopancreas of the exposed animals after the experiment. The degree of these alterations was found to be dose-dependent. Among the histological changes in the hepatopancreas in O. montagui, a loss of cell structure was noted, especially cell remoteness and border lyses, the reduction of nuclear volume, an increase in the cytoplasm density with the presence of trace element deposits in both the nucleus and vacuoles, a disorganization and destruction of microvilli, and a condensation of the majority of cell organelles and mitochondria swelling. Through this study, we have confirmed that O. montagui can be a relevant model to assess trace metal element pollution in Tunisian coastal lagoons with the aim of using it in future biomonitoring programs.

Trace elements bioaccumulation in Porcellionides pruinosus (Brandt, 1833) and related biomarkers of exposure

In the last years, the increase of anthropogenic activities has led to a progressive pollution of ecosystems. Oniscidean isopods are a group of terrestrial animals known as excellent bio-indicators and bio-accumulators, because of their capacity to accumulate contaminants and to implement appropriate strategies of detoxification. For this study, we collected Porcellionides pruinosus from two different sites in the Corinth region (Greece), a polluted site and a control site, to assess the heavy metal pollution status. We conducted an inductively coupled plasma mass spectrometry (ICP-MS) analysis for the detection of trace elements in animals' hepatopancreas and soil; we performed also immunohistochemistry for detection of metallothioneins 1 (MT1) and heat shock protein 70 (HSP70s). The results suggest a great capacity of the species in trace elements bioaccumulation and the high degree of pollution of the area near Agioi Theodoroi where the metal pollution index (MPI) is threefolds higher than the control site, due to the presence of significantly higher concentration of arsenic, cadmium, cobalt, chromium, manganese, molybdenum, and lead found in hepatopancreas and soil. The environmental stress is confirmed by the expression of the relative biomarkers of exposure MT1 and HSP70. Our study, with a multimarker approach, consents getting a complete analysis of environmental quality and the effect of pollution on organisms and shows for the first time the heavy metals contamination status in certain Greece area. Furthermore, P. pruinosus proved to be an appropriate indicator of pollution in terrestrial ecosystems.

Toxicity of Heavy Metals to Mongoloniscus sinensis (Dollfus, 1901) (Crustacea: Isopoda: Oniscidea)

The bioaccumulation of and resistance to different heavy metals in soil was tested using Mongoloniscus sinensis, a terrestrial isopod endemic to china, and results show that: (1) the median lethal concentration (LC₅₀) of Pb, Zn, Cd in the filter paper contact test after 48 h was 197.6, 503.7, 448.0 µg cm^- 2, LC₅₀ of Pb-Zn compounds was 173.8 and 440.8 µg cm^- 2 and after 14 days of soil contamination LC50 was 2917.0, 2977.9, 5048.4 mg kg^- 1, LC₅₀ of Pb-Zn compounds was 1219 and 1463 mg kg^- 1. Thus Zn turned out to be less toxic than Cd in the filter paper contact test, while their sequence of toxicity was reversed during the soil exposure test, which shows that M. sinensis can tolerate a dose of Zn and Cd. (2) analysis of body burdens showed that the sequence of internalized metal concentrations was Pb < Cd < Zn, which indicates that heavy metals in soil can be enriched and absorbed by M. sinensis, and that it is much more efficient at absorbing Zn and Cd than Pb.

Potential of Duckweed ( Lemna minor ) for the Phytoremediation of Landfill Leachate

Phytoextraction of zinc, copper, lead, iron, and nickel from landfill leachate by duckweed (L. minor) was investigated every 3 days over a period of 2 weeks. Bioconcentration factor and removal efficiency were also calculated. Results of this study proved that L. minor significantly reduced the concentration of heavy metals in landfill leachate. Removal efficiency of L. minor, for all the metals, from landfill leachate was more than 70% with the maximum value for copper (91%). Reduction in chemical oxygen demand (COD) and biological oxygen demand (BOD) was observed by 39% and 47%, respectively. However, other physiochemical parameters like pH, total suspended solids, (TSS) and total dissolved solids (TDS) were reduced by 13%, 33%, and 41%, respectively. The value of bioconcentration factor (BCF) was less than 1 with the maximum figure for copper (0.84) and lead (0.81), showing that the plant is a moderate accumulator for these heavy metals. Duckweed (L. minor) appeared as a sustainable alternative candidate and is recommended for the treatment of landfill leachate waste water contaminants.

Cadmium and lead bioaccumulation potentials of an aquatic macrophyte Ceratophyllum demersum L.: A laboratory study

Cadmium (Cd) and lead (Pb) pollutions caused by industrial activities are one of the most serious threats to aquatic ecosystems. The aim of this study is to investigate the Cd and Pb bioaccumulations and diverse physiological and biochemical properties of Ceratophyllum demersum L. exposed to different concentrations of Cd (0.5-2.0mg/L) and Pb (25-100mg/L) in aqueous media for 1, 3 and 5 days. Cd and Pb accumulations increased with increase in the exposure times and concentrations, and the highest accumulation values of Cd and Pb were recorded at 2mg/L (2668.33mg/kg dw) and 100mg/L (22,504.10mg/kg dw), respectively, after 5 days. However, higher bioconcentration factors (BCF) were calculated as 645.43 at 25mg/L Pb and as 1357.92 at 1mg/L Cd after 5 days. The results showed that photosynthetic pigments (chlorophyll a, b and carotenoids) and protein contents of the plants exposed to Cd and Pb toxicities decreased with increasing metal concentration and exposure time, whereas their malondialdehyde (MDA) contents increased. Additionally, the single and synergistic effects of duration and metal concentration on the fresh and dry weights of the plant were determined. The results of this study reveal that C. demersum, propagated by tissue culture technique, can be used effectively in the phytoremediation of aquatic environments contaminated by Cd and Pb. This study will also make a positive contribution to the progression of new phytotechnologies on the purpose of the remediation of wastewater by plants in future.

Metallothioneins and heat shock proteins 70 in Armadillidium vulgare (Isopoda, Oniscidea) exposed to cadmium and lead

The heavy metals bioaccumulation capability in Armadillidium vulgare feeded with chestnut leaves contaminated with various sublethal concentrations of Cd and Pb, was evaluated under laboratory conditions. The metal concentration found in the hepatopancreas of treated animals, as measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), affected the expression and localization of MT and HSP70 as shown by immunohistochemical and western blotting analysis. The Cd content of the animals treated with the various concentrations of the metal has been always higher than that of chestnut leaves contaminated. The accumulation of Pb was, instead, always modest compared to the content of the chestnut leaves. The immunohistochemical investigation in hepatopancreas tissue of animals treated with increasing concentrations of Cd and Pb, by using the anti-MT and anti-HSP70 antibodies, has provided a response clearly positive even if differentiated in relation to the metal and concentration tested. In particular, a positive response to anti-MT antibody was detected in B and S cells nuclei and S cells cytoplasm; the localization of HSP70 was particularly intense at the cell surface. Western blotting analysis showed significant up-regulation of the expression (about 2.6 fold) of HSP70 proteins in the hepatopancreas of animals exposed to highest Pb concentrations respect to control. Moreover, samples exposed to higher Cd and Pb concentrations showed a higher expression of MT (3.2 fold and 4 fold respectively) compared to control. In summary, our data beyond to clearly demonstrate for the first time the expression of MT in terrestrial isopods, suggest that A. vulgare would be a suitable organism for assessing Cd and Pb exposure in environments threatened by metal pollution as suggested by the modulation of the biomarkers MT and HSP70.

Validation of Armadillo officinalis Dumèril, 1816 (Crustacea, Isopoda, Oniscidea) as a bioindicator: in vivo study of air benzene exposure

This study tests the potential for using Armadillo officinalis as a bioindicator of exposure to and activation of benzene metabolic pathways using an in vivo model. A. officinalis specimens collected in a natural reserve were divided into a control and three test groups exposed to 2.00, 5.32 or 9.09 µg/m(3) benzene for 24h. Three independent tests were performed to assess model reproducibility. Animals were dissected to obtain three pooled tissue samples per group: hepatopancreas (HEP), other organs and tissues (OOT), and exoskeleton (EXO). Muconic acid (MA), S-phenylmercapturic acid (S-PMA), two human metabolites of benzene, and changes in mtDNA copy number, a human biomarker of benzene exposure, were determined in each sample; benzene was determined only in EXO. MA was measured by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection, S-PMA by triple quadrupole mass spectrometer liquid chromatography with electro spray ionization (LC-MS-ESI-TQD), mtDNA by real-time quantitative PCR and end-point PCR, and benzene by quadrupole mass spectrometer head-space gas chromatography (HSGC-MS). MA and S-PMA levels rose both in HEP and OOT; EXO exhibited increasing benzene concentrations; and mtDNA copy number rose in HEP but not in OOT samples. Overall, our findings demonstrate that A. officinalis is a sensitive bioindicator of air benzene exposure and show for the first time its ability to reproduce human metabolic dynamics.

Bioaccumulation of cadmium and lead and its effects on hepatopancreas morphology in three terrestrial isopod crustacean species

This study was designed to compare cadmium (Cd) and lead (Pb) bioaccumulation in three species of oniscidean isopods - Armadillidium granulatum Brandt, Armadillidium vulgare (Latreille) and Porcellio laevis Latreille which were exposed for three weeks to a contaminated diet, and to determine the morphological and ultrastructural changes in hepatopancreas. Metal accumulation, determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), was linearly associated with the exposed concentration and was a function of the metal and the species tested. All three species accumulated lower levels of Pb than Cd. A. vulgare accumulated the largest concentration of Pb, especially at the higher doses, whereas P. laevis showed the greatest Cd accumulation, and the highest Cd concentration was lethal for all exposed species. The highest concentrations of Pb and Cd induced significant changes both in the general morphology of tubules and in the ultrastructural organization of epithelial cells in hepatopancreas. Some Pb/Cd induced alterations include: brush border disorganization; reduction of the basal labyrinth formed by the plasma membrane; condensation of some cytoplasm areas and of chromatin; rough endoplasmic reticulum and mitochondrial alterations; increase of secondary lysosomes and of type B granules in S cells. Some of the ultrastructural changes observed overlap with those induced by prolonged starvation, whereas others can be useful biomarkers of heavy metal toxicity. This study has confirmed that in terrestrial isopods, the accumulation of the different metals occurs in a species-specific manner; therefore ecological monitoring and assessment studies should consider each species individually. The research has confirmed that in the terrestrial isopods the accumulation of the different metals occurs in a species-specific way; therefore each species should first be evaluated in view of its employ in biomonitoring programs.