Molecular Characterization of MyD88 in Anodonta woodiana and Its Involvement in the Innate Immune Response to Bacterial Infection.

Myeloid differentiation factor 88 (MyD88) is a key adapter molecule in Toll-like receptor signal transduction that triggers downstream immune cascades involved in the host defense response to exogenous pathogens. However, the function of MyD88s in mollusks, especially in freshwater shellfish, remains poorly understood. In this study, a novel freshwater shellfish MyD88 (denoted AwMyD88) was characterized from Anodonta woodiana. The present AwMyD88 protein consists of 474 amino acids and contains a conserved a typical death domain (DD) and a conservative Toll/IL-1R (TIR) domain with three typical boxes. Quantitative real-time PCR (qRT-PCR) analysis showed that AwMyD88 was broadly expressed in all the examined tissues, and the highest expression level was observed in hemocytes of A. woodiana. When challenged with Aeromonas hydrophila and lipopolysaccharide (LPS), the mRNA expression levels of AwMyD88 were significantly induced in hemocytes of A. woodiana in vivo and in vitro. In addition, in vivo injection experiments revealed that MyD88 signaling pathway genes showed strong responsiveness to A. hydrophila challenge, and their expression levels were significantly upregulated in hemocytes. Knockdown of AwMyD88 reduced the transcript levels of immune related transcription factors (AwNF-κB and AwAP-1) and effectors (AwTNF, AwLYZ, AwDefense and AwAIF) during A. hydrophila infection. Moreover, subcellular localization analysis indicated that AwMyD88 was mainly localized to the cytoplasm in HEK293T cells. Finally, luciferase reporter assays revealed that AwMyD88 associates with AwTLR to activate the NF-κB and AP-1 signaling pathways in HEK293T cells. These results suggested that AwMyD88 might be involved in the host defense response to bacterial challenge, providing new insight into the immune function of the MyD88 signaling pathway in freshwater shellfish.

Evaluation of transcriptional biomarkers using a high-resolution regression approach: Concentration-dependence of selected transcripts in copper-exposed freshwater mussels (Anodonta anatina).

We tested concentration-dependence of selected gene transcripts (cat, gst, hsp70, hsp90, mt and sod) for evaluation as biomarkers of chemical stress. Contrary to the common approach of factorial designs and few exposure concentrations, we used regression across a high-resolution concentration series. Specifically, freshwater mussels (Anodonta anatina) were acutely (96 h) exposed to Cu (13 nominal concentrations, measuring 0.13-1 600 µg/L), and transcripts were measured by RT-qPCR. In digestive glands, cat, hsp90 and mt decreased with water Cu (p < 0.05), but response magnitudes saturated at < 2-fold decreases. In gills, gst, hsp70, hsp90 and mt increased with water Cu (p < 0.05). While hsp70, hsp90 and mt exceeded 2-fold increases within the exposure range, high Cu concentrations were required (38-160 µg/L). Although gill responses were generally more robust compared to digestive glands, overall small response magnitudes and moderate sensitivity may set limit for potential application as general biomarkers of chemical stress.

Copper Bioaccumulation Kinetics in Swan Mussel, Anodonta cygnea (Linnaeus, 1758) During Waterborne Exposure to CuO Nanoparticles.

This study was conducted to investigate bioaccumulation of copper in two internal organs (mantle and foot) of swan mussel, Anodonta cygnea (Linnaeus, 1758) in exposure to copper oxide nanoparticles (CuO NPs). Basal concentration of Cu in the mantle (3.15 ± 1.09 µg g-1 DW) was significantly (p < 0.05) lower than the foot (5.43 ± 1.54 µg g-1 DW). At the end of the exposure period, the highest concentration of Cu in both organs belonged to the highest exposure concentration. Calculated bioconcentration factor (BCF) values showed significant (p < 0.05) higher values for the mantle in each day and each exposure concentration (except the lowest exposure concentration) than the foot. For both organs, the highest and lowest BCFs occurred at the lowest and highest exposure concentrations, respectively. Cu concentration in both organs was significantly (p < 0.05) decreased after day 4. Based on the results, it was obvious that exposure to sub-lethal concentrations of CuO NPs would lead to the significant accumulation of copper in mantle and foot that may have adverse effects on this organism.

Active Biomonitoring of Metals with Cultured Anodonta woodiana: A Case Study in the Taihu Lake, China.

Freshwater bivalves (Anodonta woodiana), cultured in the Nanquan Aquaculture Base, were translocated to the water source area of Xidong Waterworks in the Taihu Lake for 18-months to biomonitor 13 metals, and determine the suitability of using these cultures as an indicator of long-term metal contamination. Mussel and water samples were analyzed every 6 months, with the Nanquan Aquaculture Base serving as control. Metal concentrations in water and mussels from both sites were generally within the Chinese permissible levels. Metal pollution indexes between the two sites were similar. However, the metal loads of mussels in the water source area of Xidong Waterworks were 57.3, 1.7, and 295.5-fold higher after 6-, 12-, and 18-months relative to the control mussels from the Nanquan Aquaculture Base, respectively. Moreover, the water area in Taihu Lake was moderately, considerably, and highly contaminated by Cd, Al, and Cu, respectively.

Cadmium bioaccumulation and elimination in tissues of the freshwater mussel Anodonta woodiana.

Experiments were carried out to investigate the bioaccumulation and elimination of cadmium (Cd) in tissues (kidney, gills, digestive gland, mantle, visceral mass, foot, adductor muscle and hemolymph) from the freshwater mussel, Anodonta woodiana. The mussels were exposed to subchronic Cd at concentrations of 0.168 and 0.675 mg L-1 for 28 d of bioaccumulation and 28 d of elimination. During the bioaccumulation phase, Cd bioaccumulations increased in all tissues. The highest bioaccumulation of Cd was found in the kidney. The second-highest and third-highest bioaccumulations of Cd were found in the digestive gland and gills, respectively. The Cd bioaccumulations in the tissues of A. woodiana increased with exposure time and concentration, except for hemolymph, which reached the highest value on d 14. The bioaccumulation factors (BCFs) increased with exposure time, but an inverse relationship was observed between BCFs and exposure concentration. During the elimination phase, the visceral mass showed the highest Cd elimination rate. In the kidney, digestive gland and gills, the elimination rates almost reached 40%, but their concentrations were still higher than in other tissues. Thus, we concluded that the kidney, gills and digestive gland of A. woodiana are target tissues for subchronic Cd toxicity.

Response a chronic effects of PBDE-47: Up-regulations of HSP60 and HSP70 expression in freshwater bivalve Anodonta woodiana.

Heat shock proteins (HSPs) play an important role in adaption of environmental stress by protein folding, membrane translocation, degradation of misfolded proteins and other regulatory processes. Our previous study showed oxidative stress generated from polybrominated diphenyl ether-47 (PBDE-47) could cause an acute toxicity on freshwater bivalve Anodonta Woodiana, but the effect of chronic toxicity need to be elucidated. In order to further investigate the chronic effect of PBDE-47, clams A. Woodiana were randomly divided into the PBDE-47 treated group administrated with PBDE-47 at a concentration 3.36 µg/L and control group treated with a similar volume dimethyl sulfoxide. Two complete HSP sequences were isolated from A. Woodianaa and respectively named AwHSP60 and AwHSP70. They were widely distributed in foot, gill, hepatopancreas, adductor muscle, heart, hemocytes and mantle. Administration of PBDE-47 could result in a significant up-regulation of AwHSP60 and AwHSP70 expressions in the hepatopancreas, gill and hemocytes. In the hepatopancreas, compared with that of control group, mRNA level of AwHSP60 increased more than 89.9% (P < 0.05) from day 1-15, AwHSP70 increased more 2.79 times (P < 0.01). In the gill, during experiment observed, expression of AwHSP60 increased more 2.09 times (P < 0.01) in contrasted with that of control group. Significant up-regulation of AwHSP70 expression showed a reversed U shape. In the hemocytes, AwHSP60 and AwHSP70 expressions of PBDE-47 treated group respectively increased more 2.09 times (P < 0.05) and 1.81 times (P < 0.05) compared with that of control group. These results indicated that up-regulations of AwHSP60 and AwHSP70 expression are contribute to enhancing adaption of bivalve A. Woodiana exposed to PBDE-47 treatment.

Response of selenium-dependent glutathione peroxidase in the freshwater bivalve Anodonta woodiana exposed to 2,4-dichlorophenol,2,4,6-trichlorophenol and pentachlorophenol.

2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) pose a health risk to aquatic organism and humans, and are recognized as persistent priority pollutants. Selenium dependent glutathione peroxidase (Se-GPx) belongs to the family of selenoprotein, which acts mainly as an antioxidant role in the cellular defense system. In the current study, a Se-GPx full length cDNA was cloned from Anodonta woodiana and named as AwSeGPx. It had a characteristic codon at 165TGA167 that corresponds to selenocysteine(Sec) amino acid as U44. The full length cDNA consists of 870 bp, an open reading frame (ORF) of 585 bp encoded a polypeptide of 195 amino in which conserved domain (68LGFPCNQF75) and a glutathione peroxide-1 GPx active site (32GKVILVENVASLUGTT47) were observed. Additionally, the eukaryotic selenocysteine insertion sequence (SECIS) was conserved in the 3'UTR. The AwSeGPx amino acid sequence exhibited a high similarity with that of other Se-GPx. Real-time PCR analysis revealed that AwSeGPx mRNA had a widely distribution, but the highest level was observed in hepatopancreas. AwSeGPx mRNA expression was significantly up-regulated in hepatopancreas, gill and hemocytes after 2,4-DCP, 2,4,6-TCP and PCP exposure. Under similar environment, clams A. woodiana showed a more sensitive to PCP than that of 2,4-DCP and 2,4,6-TCP. These results indicate that AwSeGPx plays a protective role in eliminating oxidative stress derived from 2,4-DCP, 2,4,6-TCP and PCP treatment.

The toxicity, bioaccumulation, elimination, conversion of the enantiomers of fipronil in Anodonta woodiana.

The enantioselective bioaccumulation and elimination of fipronil in Anodonta woodiana (A. woodiana) were studied and the main metabolites fipronil desulfinyl, fipronil sulfide and fipronil sulfone were determined. The acute toxicity of the enantiomers of fipronil and the three metabolites were also investigated. In the bioaccumulation process, fipronil in A. woodiana reached equilibrium after 11days with BCF value of 0.2, and the enantiomeric fraction (EF) values showed that the bioaccumulation was enantioselective with enantioenrichment of S-fipronil. The degradation of fipronil in A. woodiana fitted first-order kinetics model with half-lives of the enantiomers were 5.8 d for R-fipronil and 7.6 d for S-fipronil, and the EF values decreasing from 0.5 gradually indicating the R-enantiomer was preferentially degraded. The degradation of single enantiomers was also performed and the results revealed a fast conversion of R-fipronil to S-fipronil by A. woodiana. The three metabolites were all detected in A. woodiana-water system, in which fipronil sulfone and fipronil sulfide had higher concentration levels. According to the 72-h LC50 values, S-fipronil was much more toxic than the racemate and R-fipronil. Moreover, the metabolites were more toxic than the parent fipronil. The results suggested the individual enantiomers of chiral pollutants and the metabolites should be considered in the risk assessments.

Cadmium accumulation and metallothionein biosynthesis in cadmium-treated freshwater mussel Anodonta woodiana.

This study investigated the distribution of cadmium (Cd) and the protein level of metallothionein (MT) and examined the relationship of Cd accumulation and the MT concentration in different tissues of freshwater mussel Anodonta woodiana following Cd treatment. The mussels were exposed to Cd (4.21, 8.43, 16.86, 33.72 and 67.45 mg L-1) for 24, 48, 72 and 96 h, respectively. After Cd treatment, the gills, mantle, foot, visceral mass and digestive gland tissues were collected for analysis. We found that, in the controls, Cd distributed in all tissues in the concentration order of gills>mantle>foot>visceral mass>digestive gland. Upon Cd treatment, Cd concentration significantly increased in all tissues. The highest Cd accumulation was found in the digestive gland, which was 0.142 mg g-1 (P<0.05). MT levels in the gills and mantle of the mussels increased significantly (P<0.05), which were in positive correlation with Cd accumulation in the tissues (P<0.05). In conclusion, our results demonstrated a correlation between Cd accumulation and MT up-regulation in gills and mantle of the mussels after Cd treatment. It is suggested that the protein level of MT in gills and mantle of Anodonta woodiana is a good biomarker for Cd contamination.

Uptake of contaminants of emerging concern by the bivalves Anodonta californiensis and Corbicula fluminea.

Uptake of seven contaminants regularly detected in surface waters and spanning a range of hydrophobicities (log D(ow) -1 to 5) was studied for two species of freshwater bivalves, the native mussel Anodonta californiensis and the invasive clam Corbicula fluminea. Batch systems were utilized to determine compound partitioning, and flow-through systems, comparable to environmental conditions in effluent dominated surface waters, were used to determine uptake and depuration kinetics. Uptake of compounds was independent of bivalve type. Log bioconcentration factor (BCF) values were correlated with log D(ow) for nonionized compounds with the highest BCF value obtained for triclocarban (TCC). TCC concentrations were reduced in the water column due to bivalve activity. Anionic compounds with low D(ow) values, i.e., clofibric acid and ibuprofen, were not removed from water, while the organic cation propranolol showed biouptake similar to that of TCC. Batch experiments supported compound uptake patterns observed in flow-through experiments. Contaminant removal from water was observed through accumulation in tissue or settling as excreted pseudofeces or feces. The outcomes of this study indicate the potential utility of bivalve augmentation to improve water quality by removing hydrophobic trace organic compounds found in natural systems.

The swan mussel (Anodonta cygnea) in Anzali wetland of Iran, a potential biomonitor for Cd and Pb.

Protecting wetlands from environmental pollution has been of significant importance, as they are the vital habitats for various kinds of birds and animals. This study has aimed to monitor the contamination of Cd and Pb in Anzali wetland, located in the north of Iran using a mussel biomonitor. The contents of Cd and Pb were measured in the surface sediment, the soft tissue, and the shell of A. cygnea. The samples were collected from four sites in the region. The results demonstrated that the shell of A. cygnea can be employed as a precise case for biomonitoring of Cd and Pb, due to the higher biota-sediment accumulation factor and the lower coefficient of variation values found in the shell compared with the soft tissue, and also according to the positive correlation between Cd and Pb levels in the shell of A. cygnea and the sediment.

Effect of in situ exposure history on the molecular responses of freshwater bivalve Anodonta anatina (Unionidae) to trace metals.

The goal of the study was to assess the adequacy of molecular responses in mollusks in relation to their in situ exposure history. Freshwater male bivalve mollusks Anadonta anatina (Unionidae) from polluted (A) and unpolluted (F) sites were subjected to 14 days of exposure to copper (Cu(2+), 10 µg L(-1)), zinc (Zn(2+), 130 µg L(-1)) or cadmium (Cd(2+), 15 µg L(-1)). The comparison of two control groups showed that the specimens from site A had higher levels of Cu, Zn and Cd and metallothionein (measured both through metal (MT-Me), and protein (MT-SH) levels) in the tissues. Cytotoxicity (low lysosomal membrane stability), low glutathione level, high antioxidant and apoptotic enzymes activities, lipid and protein oxidative injury, depletion of ethoxyresorufin-O-deethylase (EROD) in digestive gland, high vitellogenin-like protein (Vtg-LP) concentration in gonads confirmed the effect of toxic environment on this group. Exposures provoked increased number of hemocytes with micronuclei (by 100-500%) and nuclear abnormalities (by 50-400%) (genotoxicity), elevation of caspase-3 (in 1.5-10 times) and/or Vtg-LP (by 70-310%) levels in all groups. However, the responses were strongly dependent on the origin of mussels. Exposed mussels from site F demonstrated typical for the effect of toxic metals elevation of MT-SH (by 100-380%) and MT-Me (up to seven times) levels and accumulation of metals (with a few exceptions) in the tissues. Conversely, in the mussels inhabiting site A, exposures caused the decrease of metal (by 37% for Cu, by 62% for Zn, by 50% for Cd), MT-SH (by 68% in ZnA group) and MT-Me (by 50-68%) levels. That was accompanied with increase of cytotoxicity and EROD activity (by 144-240%). High level of protein carbonyls was the distinguished feature of all groups from site A. Hence, despite high efficiency of metal detoxification and oxidative stress responses in the mussels, in the specimens from spontaneously polluted site they were impaired.

Evaluation of biotargeting and ecotoxicity of Co²âº-containing nanoscale polymeric complex by applying multi-marker approach in bivalve mollusk Anodonta cygnea.

Cobalt (Co(2+)) is present in many nanoscaled materials created for various applications. The key goal of our study was to develop sensitive approaches for assessing the bio-risks associated with using novel Co(2+)-containing nanoscaled polymeric complex (Co-NC). Freshwater bivalve mollusk Anodonta cygnea (Unionidae) was subjected to 14 d action of the developed Co-NC, as well as of Co(2+) applied in the corresponding concentration (50 µg L(-1)) or polymeric substance (PS). All experimental groups under study have demonstrated signs of toxic targeting, notably changes in DNA characteristics, oxidative stress (with particularities in each exposed group) and activation of anaerobiosis (Co(2+) and Co-NC). However, the group exposed to Co-NC showed some advantages that can be related to the activation of metallothionein (MT) function (increase in the level of MT-related SH-groups (MT-SH)): low level of oxyradical formation, no increase in protein carbonylation and vitellogenin-like proteins concentration unlike in Co(2+) and PS exposed groups. On the other hand, Co(2+) increased metal (Co, Cu, Zn and Cd) binding to MT (MT-Me) without changes in MT-SH level jointly with activation of oxyradical formation and apoptosis and decreasing of lysosomal membrane stability. PS per se initiated unbalanced changes in activities of the biotransformation enzymes ethoxyresorufin-O-deethylase and glutathione-S-transferase. Thus, Co(2+) complexing with the developed PS prevented bio-toxic effects of free Co(2+) ions and PS per se, at least in the studied hydrobiont. The MT-SH was the main distinguishing index of Co-NC group selected by classification and regression tree analysis.

Vulnerability of biomarkers in the indigenous mollusk Anodonta cygnea to spontaneous pollution in a transition country.

The aim of this study was to estimate the sensitivity of biomarkers of stress and exposure in the bivalve mollusk Anodonta cygnea to spontaneous anthropogenic activities typical for the Western Ukraine. Three sites were examined during spring, summer and autumn: an agricultural site (A); the cooling pond of nuclear power plant (N) and a forestry close to the municipal water inlet (F). Common temporal changes of a battery of biochemical markers in the gills and hemolymph and morphological characteristics were shown by discriminant functional analysis. Classification trees built on the basis of the screened biomarkers demonstrated persistent peculiarities at each site: genotoxicity (nuclear abnormalities) at site A and endocrine disruption (high levels of vitellogenin-like proteins (Vtg-LP) in hemolymph) at site F. Interim local effects were best characterized by metallothionein (MT) concentrations, lipid peroxidation (LPO), activities of glutathione S-transferase and lactate dehydrogenase, and the conditional index of the gills. In autumn, the mollusks from the three sites revealed the highest differences in pollution status: the activation of antioxidant defense and cholinesterase were typical for site A, highest levels of MT related to high levels of Cu and Cd in the water at site B, and a steep increase in the level of Vtg-LP and the decrease of lysosomal membrane stability were recorded at the site selected as reference (F). The biomarker alterations recorded at site F were later related to an emergency event at the municipal dump located nearby. Thus, our case study demonstrated the reliability of using biomarkers of exposure to assess both long-term and accidental environmental pollution loads.

Trace element accumulation in bivalve mussels Anodonta woodiana from Taihu Lake, China.

Data are presented for 13 trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, and Pb) in 38 bivalve mussels Anodonta woodiana from four separate sites (Huzhou, Dapu, Sansandao, and Manshan) around the Taihu Lake of China. All elemental concentrations generally ranked in decreasing order, Mn > Fe > Zn > As ≈ Cu ≈ Cd ≈ Se > Pb > Mo ≈ Ag, except that Cr, Co, and Ni were not detected. Anodonta woodiana was able to bioaccumulate essential Mn and toxic Cd to the extremely high level of 19,240 and 53 mg/kg dry weight, respectively. Geographical differences in the concentrations of trace elements were usually significant between sampling sites except for As and Pb, and the mussels from Sanshandao site had mostly accumulated or were contaminated with essential and toxic elements. The residue level of Cd in A. woodiana from the Sanshandao and Manshan sites appeared to be even higher than those of the essential elements Cu and Se, and exceeded the corresponding maximum residue limits of China. The present study provides the most recent information on trace element bioaccumulation or contamination in Taihu Lake and, further, suggests that A. woodiana can be used as a suitable bioindicator for inland water environmental monitoring.

A comparative study on the uptake of polycyclic aromatic hydrocarbons by Anodonta californiensis.

Uptake of polycyclic aromatic hydrocarbons (PAHs) by the freshwater bivalve mollusc Anodonta californiensis was examined in the presence and absence of surfactant in order to gain further insight into mixture toxicity and to predict whether certain mixtures have negative and/or positive effects on aquatic organisms. In the presence of surfactant, the uptake of anthracene or chrysene was higher than that of naphthalene, given the same concentration in the solution. In the absence of surfactant, the trend was similar, but the uptakes were increased by approximately 100% compared to those in the presence of surfactant. On the uptake of naphthalene, the presence of anthracene showed only minor influence. The uptake of anthracene was affected by both naphthalene and chrysene. The uptake of chrysene was influenced by neither naphthalene nor anthracene. There was no observable displacement of divalent cations from the surface of the gill membrane by any of the PAHs studied.

Multi-biomarkers approach in different organs of Anodonta cygnea from the Dnister Basin (Ukraine).

The aim of this study was to compare environmental quality in two sites in western Ukraine-rural (R) and urbanized (U)-with the usage of the resident bivalve mollusk Anodonta cygnea. The study was realized during three seasons. The metal uptake and a set of biochemical markers were determined. For each season, Cd and metallothioneins (MTs) contents in the digestive gland and gills of the mollusc were higher at the U site, reflecting its chronic pollution. The oxidative stress in the mollusk was observed at the U site during spring and at the R site during summer and autumn according to the differences in Mn-superoxide dismutase and catalase activities, O (2) (*-) production, lipid peroxidation, and glutathione levels. The elevated vitellogenin-like protein levels in the hemolymph and the ethoxyresorufin-O-deethylase activity in the digestive gland in summer-autumn suggested pollutions by organic substances at the R site. The acetylcholinesterase activity was similar in both groups. The centroid grouping analysis of biomarkers and morphological and water indexes demonstrated the clear differentiation of general response in each group in spring and, at the R site, in summer and autumn but its similarity at the U site in summer and autumn.

HCH and DDT Residues in Bivalves Anodonta woodiana from the Taihu Lake, China.

The present article attempts to use freshwater bivalves Anodonta woodiana for monitoring the pollution of hexachlorocyclohexane isomers (alpha-, beta-, gamma-, delta-HCH), dichlorodiphenyltrichloroethanes (o, p', p, p'-DDT) and metabolites (p, p'-DDE, p, p'-DDD) in the Taihu Lake, China. A total of 36 bivalves were sampled from 4 sites of Huzhou city, Dapu of Yixing city, Xueyan of Changzhou city, and Wulihu of Wuxi city around the lake in August-October 2004. The organochlorines were detected in all bivalves, and the mean concentration of SigmaDDTs (7.07 ng/g wet weight) was significantly higher than that of SigmaHCHs (2.37 ng/g wet weight). Overall, SigmaHCHs are at the highest concentrations in the bivalves from the Dapu and Huzhou site, whereas SigmaDDTs are at highest concentrations in the bivalves from the Wulihu site. Compositions of SigmaHCHs were predominated by alpha- and gamma-HCH isomers in the bivalves from all four study sites. Among these sampling sites, p, p'-DDT exhibited the highest percentage in the bivalves from Huzhou site. Furthermore, significant regional variations in compositions of both SigmaDDTs and SigmaHCHs had been identified. The residue levels of SigmaDDTs and SigmaHCHs in the bivalves of the present study were much lower than the corresponding residue limits for aquatic products of Ministry of Agriculture of China, FDA, and FAO/WHO. These findings suggest that Anodonta woodiana could serve as a unique bioindicator to monitor the HCH and DDT pollutions in the freshwater environment.

Uptake and effect of mercury on amino acid losses from the gills of the bivalve mollusks Mytilus californianus and Anodonta californiensis.

Inorganic mercury (Hg(2+)) and herbicides are important contaminants of world water systems with effects on aquatic organisms and humans. The uptake of Hg(2+) and glycine by the gills of the bivalve mollusks Mytilus californianus and Anodonta californiensis was determined. Additionally, the effects of glycine, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4-dinitrophenol (DNP) on the uptake of Hg(2+) were also determined. The loss of primary amines from the excised gills of both species was measured in the presence and absence of Hg(2+) or MeHg(+). The results indicate that (1) the uptake of Hg(2+) is approximately equivalent in both species; (2) comparison of the uptakes with that of inulin, which occupies only extracellular space, shows that Hg(2+) is taken up; (3) the uptake of Hg(2+) is slightly altered by the presence of glycine and herbicides such as 2,4-D and DNP; (4) the rate of loss of primary amines was highly increased relative to the control by the presence of Hg(2+) and to a lesser extent MeHg(+) for both species. These results showed that both inorganic and MeHg(+) are effective in disrupting the permeability of cell membranes, causing leakage of essential amino acids from the cell. This could result in discharge of potential gradients, reduced efficiency of energy coupling, and consequently cell death.

[The effect of pesticide acetamiprid on biochemical markers in tissues of fresh water bivalve mussels Anodonta cygnea L. (Unionidae)].

The effects of ecological real concentration of pesticide "Mospilan" (active substance - acetamiprid) on the status of oxidative stress biomarkers, neurotoxicity and metallothioneins' (MTs) characteristics of freshwater bivalve mussels Anodonta cygnea were investigated. The prooxidative changes (decrease of superoxide dismutase activity, reduced glutathione content, increase of content of lipid and proteins peroxidation products) and decrease of the MTs content in gills and especially in digestive gland in the experimental group were reflected, whereas acetylcholinesterase activity was not changed. The effect of acetamiprid induces the appearance of additional chromatographic MTs form.