Acetylcholinesterase activities in marine snail (Cronia contracta) as a biomarker of neurotoxic contaminants along the Goa coast, West coast of India

Possible Interaction between ZnS Nanoparticles and Phosphonates on Mediterranean Clams Ruditapes decussatus

This study aims to evaluate the toxicity of ZnS nanoparticles (ZnS NP50 = 50 µg/L and ZnS NP100 = 100 µg/L) and diethyl (3-cyano-1-hydroxy-2-methyl-1-phenylpropyl)phosphonate or P (P50 = 50 µg/L and P100 = 100 µg/L) in the clams Ruditapes decussatus using chemical and biochemical approaches. The results demonstrated that clams accumulate ZnS NPs and other metallic elements following exposure. Moreover, ZnS NPs and P separately lead to ROS overproduction, while a mixture of both contaminants has no effect. In addition, data showed that exposure to P100 resulted in increased levels of oxidative stress enzyme activities catalase (CAT) in the gills and digestive glands. A similar trend was also observed in the digestive glands of clams treated with ZnS100. In contrast, CAT activity was decreased in the gills at the same concentration. Exposure to ZnS100 and P100 separately leads to a decrease in acetylcholinesterase (AChE) levels in both gills and digestive glands. Thus, AChE and CAT after co-exposure to an environmental mixture of nanoparticles (ZnS100) and phosphonate (P100) did not show any differences between treated and non-treated clams. The outcome of this work certifies the use of biomarkers and chemical assay when estimating the effects of phosphonate and nanoparticles as part of an ecotoxicological assessment program. An exceptional focus was given to the interaction between ZnS NPs and P. The antioxidant activity of P has been demonstrated to have an additive effect on metal accumulation and antagonistic agents against oxidative stress in clams treated with ZnS NPs.

Different toxicity to liver and gill of zebrafish by selenium nanoparticles derived from bio/chemical methods

With the wide application of selenium nanoparticles (SeNPs) in pharmaceutical fields, the toxicity assessment is of great significance. In this study, zebrafish were selected as model organisms to compare the toxicity of SeNPs derived from biological and chemical methods. The results showed that the size of bio-SeNPs was about 5-fold bigger than chem-SeNPs. When exposed to SeNPs for 96 h, LC₅₀ of bio-SeNPs and chem-SeNPs was 1.668 mg/L and 0.699 mg/L, respectively. Compared with the control, the results showed a significant increase in oxidative toxicity index (P < 0.05), such as glutathione (GSH), superoxide dismutase (SOD) of the liver, and gill in SeNPs-treated group. The neurotoxicity index, such as acetylcholinesterase (AchE) and Na⁺-K⁺-ATP enzyme activity, was significantly decreased both in the liver and gill (P < 0.05). It was found that the toxicity of bio-SeNPs to the liver and gill of zebrafish was lower than chem-SeNPs and the toxicity to the liver was higher than gill. In this study, the toxicity of chem-SeNPs and bio-SeNPs to the target organs of zebrafish were systematically evaluated, which provided the basis for the safe application of SeNPs synthesized by different pathways.

Assessment of seasonal and spatial variation responses of integrated biomarkers in two marine sentinel bivalve species: Agadir Bay (Southern of Morocco)

The present study aims to assess the effects of contamination of the Agadir bay coasts using bivalves as a biomonitoring sentinel species. Seasonal variations of biochemical composition in terms of total protein content and oxidative stress biomarkers including glutathione-S-transferase, malondialdehyde, catalase and acetylcholinesterase were evaluated in the soft tissues of Scrobicularia plana and Donax trunculus specimens. The latter were collected from two sites in Agadir bay during two-year span (2018-2020). The Integrated Biomarker Response Index (IBR) was performed to classify the stress response in both species and to assess the level of exposure to xenobiotics. The data showed maximum annual values of acetylcholinesterase and malondialdehyde for Donax trunculus in Agadir beach (AG) with 6.25 nmol/mn/mg and 3 nmol/mg of protein, respectively. Those of catalase and glutathione-S-transferase for Scrobicularia plana in Oued Souss estuary (OS) were of 4.41 μmol/mn/mg and 14.43 nmol/mn/mg of protein, respectively. The studied species are considered good indicators in aquatic ecosystems.

Neurotoxicity in Marine Invertebrates: An Update

Invertebrates represent about 95% of existing species, and most of them belong to aquatic ecosystems. Marine invertebrates are found at intermediate levels of the food chain and, therefore, they play a central role in the biodiversity of ecosystems. Furthermore, these organisms have a short life cycle, easy laboratory manipulation, and high sensitivity to marine pollution and, therefore, they are considered to be optimal bioindicators for assessing detrimental chemical agents that are related to the marine environment and with potential toxicity to human health, including neurotoxicity. In general, albeit simple, the nervous system of marine invertebrates is composed of neuronal and glial cells, and it exhibits biochemical and functional similarities with the vertebrate nervous system, including humans. In recent decades, new genetic and transcriptomic technologies have made the identification of many neural genes and transcription factors homologous to those in humans possible. Neuroinflammation, oxidative stress, and altered levels of neurotransmitters are some of the aspects of neurotoxic effects that can also occur in marine invertebrate organisms. The purpose of this review is to provide an overview of major marine pollutants, such as heavy metals, pesticides, and micro and nano-plastics, with a focus on their neurotoxic effects in marine invertebrate organisms. This review could be a stimulus to bio-research towards the use of invertebrate model systems other than traditional, ethically questionable, time-consuming, and highly expensive mammalian models.

Chemical availability versus bioavailability of potentially toxic elements in mining and quarry soils

Abandoned mining and quarry areas are sources of potentially toxic elements (PTEs), through lixiviates or transfer processes of bioavailable fractions from mining wastes and tailings. In this study, earthworms (Eisenia fetida Savigny, 1826) were exposed for 28 days to two mining soils from a lead/zinc mine and two quarry soils from an old serpentine quarry. Despite their pseudo total metal contents, a previous characterization of these soils pointed out for a low chemical availability of PTEs. Therefore, a multibiomarker approach was used and the response of E. fetida to soils was assessed through the analysis of neurotoxic, oxidative stress, energy metabolism and DNA damage biomarkers (acetylcholinesterase, catalase, glutathione-s-transferase, lactate dehydrogenase, lipid peroxidation and DNA strand breaks). Metal bioaccumulation was also assessed to evaluate bioavailability and organism's exposure. Results showed that high contents of PTEs were recorded in the whole body of earthworms exposed to lead/zinc mine. However, the bioaccumulation factors for worms exposed to soils from both sampling sites were <1 due to the high PTEs contents in soils. Earthworms exposed to both types of soils displayed neurotoxic and energy metabolism effects. However, significant levels of oxidative stress and DNA damage were recorded only for earthworms exposed to lead/zinc mine soils. This study demonstrated that despite the low availability of PTEs showed by previous sequential chemical extractions, the results obtained from the direct toxicity assessment performed in this study, highlight the importance of a multibiomarker approach using soil organisms to provide a better evaluation of soils pollution.

Biochemical and reproductive effects of red mud to earthworm Eisenia fetida

Red mud (RM) is the main waste of alumina production whose disposal poses a problem. The research of various possible effects of red mud on soil organisms has been scarce. We have exposed earthworms (Eisenia fetida) to red mud: artificial soil mixtures. The tested samples of red mud were of different origin: Croatian (CRRM) and Hungarian (HURM). The effects of exposure on the metabolic and oxidative status of earthworms were measured using several biochemical biomarkers (acetylcholinesterase, catalase and glutathione S-transferase activity and metallothionenin content) and reproductive success was assessed upon counting the number of hatched juveniles. The LC₅₀ value for CRRM was 40% and for HURM 62% of red mud in the growth medium on weight basis, respectively. A significant effect (p < 0.001) of the RM concentration and origin, as well as significant interactions between the origin of RM and the applied concentrations on all measured biomarkers were observed. CRRM had a higher content of different metals as well as a higher conductivity in comparison to HURM. The reproduction was inhibited after exposure to both RMs. Namely, 25% CRRM caused a 53.26% reduction in the number of juveniles, whereas 18% HURM caused a 68.84% reduction, and 50% HURM caused 97.9% reduction, respectively. Both RMs caused changes in the measured biomarkers related to an oxidative stress. Consequently, the possible adverse effects on soil organisms before the environmental application of red mud should be assessed to avoid further environmental damage.

Comparative study of selenium and selenium nanoparticles with reference to acute toxicity, biochemical attributes, and histopathological response in fish

Recent studies have demonstrated that selenium (Se) and selenium nanoparticles (Se-NPs) exhibited toxicity at a higher concentration. The lethal concentration of Se and Se-NPs was estimated as 5.29 and 3.97 mg/L at 96 h in Pangasius hypophthalmus. However, the effect of different definite concentration of Se (4.5, 5.0, 5.5, and 6.0 mg/L) and Se-NPs (2.5, 3.0, 3.5, and 4.0 mg/L) was decided for acute experiment. Selenium and Se-NPs alter the biochemical attributes such as anti-oxidative status [catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST) activities], neurotransmitter enzyme, cellular metabolic enzymes, stress marker, and histopathology of P. hypophthalmus in a dose- and time-dependent manner. CAT, SOD, and GST were significantly elevated (p < 0.01) when exposed to Se and Se-NPs, and similarly, a neurotransmitter enzyme (acetylcholine esterase (AChE)) was significantly inhibited in a time- and dose-dependent manner. Further, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and malate hydrogenase were noticeably (p < 0.01) affected by Se and Se-NPs from higher concentration to lower concentration. Stress markers such as cortisol and HSP 70 were drastically enhanced by exposure to Se and Se-NPs. All the cellular metabolic and stress marker parameters were elevated which might be due to hyperaccumulation of Se and Se-NPs in the vital organ and target tissues. The histopathology of liver and gill was also altered such as large vacuole, cloudy swelling, focal necrosis, interstitial edema, necrosis in liver, and thickening of primary lamellae epithelium and curling of secondary lamellae due to Se and Se-NP exposure. The study suggested that essential trace element in both forms (inorganic and nano) at higher concentration in acute exposure of Se and Se-NPs led to pronounced deleterious alteration on histopathology and cellular and metabolic activities of P. hypophthalmus.

Genotoxicity of two heavy metal compounds: lead nitrate and cobalt chloride in Polychaete Perinereis cultrifera

The present study explores the in vivo and in vitro genotoxic effects of lead nitrate, [Pb(NO₃)₂] a recognized environmental pollutant and cobalt chloride (CoCl₂), an emerging environmental pollutant in polychaete Perinereis cultrifera using comet assay. Despite widespread occurrence and extensive industrial applications, no previous published reports on genotoxicity of these compounds are available in polychaete as detected by comet assay. Polychaetes were exposed in vivo to Pb(NO₃)₂ (0, 100, 500, and 1000 μg/l) and CoCl₂ (0, 100, 300, and 500 μg/l) for 5 days. At 100 μg/l Pb(NO₃)₂ concentration, tail DNA (TDNA) values in coelomocytes were increase by 1.16, 1.43, and 1.55-fold after day 1, day 3, and day 5, whereas, OTM showed 1.12, 2.33, and 2.10-fold increase in in vivo. Pb(NO₃)₂ showed a concentration and time-dependent genotoxicity whereas CoCl₂ showed a concentration-dependent genotoxicity in in vivo. A concentration-dependent increase in DNA damage was observed in in vitro studies for Pb(NO₃)₂ and CoCl₂. DNA damage at 500 μg/L showed almost threefold increase in TDNA and approximately fourfold increase in OTM as compared to control in in vitro. Our studies suggest that Pb(NO₃)₂ and CoCl₂ have potential to cause genotoxic damage, with Pb(NO₃)₂ being more genotoxic in polychaete and should be used more carefully in industrial and other activities. Graphical abstract.

Inhibition of acetylcholinesterase and cytochrome oxidase activity in Fasciola gigantica cercaria by phytoconstituents

Fasciolosis is an important cattle and human disease caused by Fasciola hepatica and Fasciola gigantica. One of the possible methods to control this problem is to interrupt the life cycle of Fasciola by killing its larva (redia and cercaria) in host snail. Molecular identification of cercaria larva of F. gigantica was done by comparing the nucleotide sequencing with adult F. gigantica. It was noted that nucleotide sequencing of cercaria larva and adult F. gigantica were 99% same. Every month during the year 2011-2012, in vivo treatment with 60% of 4 h LC50 of phyto cercaricides citral, ferulic acid, umbelliferone, azadirachtin and allicin caused significant inhibition of acetylcholinesterase (AChE) and cytochrome oxidase activity in the treated cercaria larva of F. gigantica. Whereas, activity of both enzymes were not significantly altered in the nervous tissues of vector snail Lymnaea acuminata exposed to same treatments. Maximum reduction in AChE (1.35% of control in month of June) and cytochrome oxidase (3.71% of control in the month of July) activity were noted in the cercaria exposed to 60% of 4 h LC50 of azadirachtin and allicin, respectively.

Arylamine N-acetyl Transferase (NAT) in the blue secretion of Telescopium telescopium: xenobiotic metabolizing enzyme as a biomarker for detection of environmental pollution

Telescopium telescopium, a marine mollusc collected from Sundarban mangrove, belongs to the largest mollusca phylum in the world and exudes a blue secretion when stimulated mechanically. The blue secretion was found to metabolize (preferentially) para-amino benzoic acid, a substrate for N-acetyl transferase (NAT), thereby indicating acetyl transferase like activity of the secretion. Attempts were also made to characterise bioactive fraction of the blue secretion and to further use this as a biomarker for monitoring of marine pollution. NAT like enzyme from marine mollusc is a potential candidate for detoxification of different harmful chemicals. A partially purified extract of blue secretion was obtained by fractional precipitation with (NH₄)₂SO₄. From different fractions obtained by precipitation, the 0–30% fraction (30S) displayed NAT like activity (using para amino benzoic acid as a substrate with para nitrophenyl phosphate or acetyl coenzyme A as acetyl group donors). Maximum NAT like enzyme activity was attained at 25°C and at a pH of 6. The enzyme activity was found to be inhibited by 5 mM phenyl methyl sulfonyl fluoride. The divalent metal ions reduced NAT like activity of 30S. Moreover, Cu²⁺ and Zn²⁺ (at concentration of 1 mM) completely inhibited NAT activity. The thermal stability and bench-top stability studies were performed and it was found that the enzyme was stable at room temperature for more than 24 hours. Results from the present study further indicate that heavy metal content in blue secretion gradually decreased from pre-monsoon to post-monsoon season, which also corresponded to the change in NAT like activity. Therefore, this article stresses the importance of biomarker research for monitoring pollution.

Seasonal variation in abiotic factors and ferulic acid toxicity in snail-attractant pellets against the intermediate host snail Lymnaea acuminata

Laboratory evaluation was made to access the seasonal variations in abiotic environmental factors temperature, pH, dissolved oxygen, carbon dioxide, electrical conductivity and ferulic acid toxicity in snail-attractant pellets (SAP) against the intermediate host snail Lymnaea acuminata in each month of the years 2010 and 2011. On the basis of a 24-h toxicity assay, it was noted that lethal concentration values of 4.03, 3.73% and 4.45% in SAP containing starch and 4.16, 4.23% and 4.29% in SAP containing proline during the months of May, June and September, respectively, were most effective in killing the snails, while SAP containing starch/proline + ferulic acid was least effective in the month of January/February (24-h lethal concentration value was 7.67%/7.63% in SAP). There was a significant positive correlation between lethal concentration value of ferulic acid containing SAP and levels of dissolved O2 /pH of water in corresponding months. On the contrary, a negative correlation was observed between lethal concentration value and dissolved CO2 /temperature of test water in the same months. To ascertain that such a relationship between toxicity and abiotic factors is not co-incidental, the nervous tissue of treated (40% and 80% of 24-h lethal concentration value) and control group of snails was assayed for the activity of acetylcholinesterase (AChE) in each of the 12 months of the same year. There was a maximum inhibition of 58.43% of AChE, in snails exposed to 80% of the 24-h lethal concentration value of ferulic acid + starch in the month of May. This work shows conclusively that the best time to control snail population with SAP containing ferulic acid is during the months of May, June and September.

Biochemical response of anthracene and benzo [a] pyrene in milkfish Chanos chanos

Polycyclic aromatic hydrocarbons (PAHs) are common toxic pollutants found in the aquatic environment, and the assessment of their impact on biota is of considerable concern. The aim of the present research was to study the acute toxicity, bioaccumulation and biochemical response of milkfish Chanos chanos (Forsskal) to two selected PAHs: anthracene and benzo [a] pyrene. Acute toxicity test results were evaluated by the Probit analysis method and 96h LC(50) values for C. chanos exposed to anthracene was 0.030mgl(-1) and 0.014mgl(-1) for benzo [a] pyrene. Bioaccumulation concentration of anthracene was high when compared to benzo [a] pyrene. Biomarkers indicative of neurotoxicity (acetylcholinesterase, AchE), oxidative stress (lipid peroxidation, LPO and catalase, CAT) and phase II biotransformation of xenobiotics (glutathione S transferase, GST and reduced glutathione, GSH) were measured to assess effects of selected PAHs. Anthracene and benzo [a] pyrene increase LPO and CAT level of C. chanos suggesting that these PAHs may induce oxidative stress. Both the PAHs inhibited AchE indicating that they have at least one mechanism of neurotoxicity in common: the disruption of cholinergic transmission by inhibition of AChE. An induction of C. chanos glutathione S-transferase (GST) activity was found in fish exposed to benzo [a] pyrene, while an inhibition was observed after exposure to anthracene. These results suggest that GST is involved in the detoxification of benzo [a] pyrene, but not of anthracene.

Adsorption and inhibition of acetylcholinesterase by different nanoparticles

Manufactured nanoparticles can be toxic via interactions with proteins and enzymes. Acetylcholinesterase (AChE) is a key enzyme present in the brain, blood and nervous system. Therefore, adsorption and inhibition of AChE by eight nanoparticles, SiO(2), TiO(2), Al(2)O(3), Al, Cu, Cu-C (carbon-coated copper), multi-walled carbon nanotubes (MWCNT) and single-walled carbon nanotubes (SWCNT), were examined. A modified Ellman assay was used to measure AChE activity because nanoparticles could adsorb the yellowish product, 5'-mercapto-2'-nitrobenzoic acid (5-MNBA) during the color development. Adsorption and inhibition rates by nanoparticles were estimated by decrease of AChE activities compared to controls. Carbon nanotubes had high affinity for AChE adsorption, the highest being SWCNT (94%). Nano SiO(2) and Al(2)O(3) showed the lowest adsorption. Inhibition by the tested nanoparticles was primarily caused by adsorption. However, Cu(2+) release in Cu and Cu-C nanoparticle suspensions caused 40% and 45% of AChE activity reduction, respectively. AChE inhibition by bulk Cu and activated carbon particles was also measured for comparison, showing that the inhibition by bulk particles was lower than their counterpart nanoparticles. For bulk Cu particles, AChE inhibition was primarily caused by dissolved ions, but mainly by adsorption for activated carbon. AChE inhibition by Cu, Cu-C, MWCNT and SWCNT had dose-response relationships, and their median inhibitory concentrations (IC(50)) were 4, 17, 156 and 96mgL(-1), respectively, showing that these nanoparticles may have neurotoxicity and AChE may have potential to be used as a biomarker for nanoparticles.

Acetylcholinesterase: a potential biochemical indicator for biomonitoring of fertilizer industry effluent toxicity in freshwater teleost, Channa striatus

Monitoring of acetylcholinesterase (EC: 3.1.1.7, AChE) activity has been widely used in aquatic and terrestrial systems as an indicator of pollutant exposure. The reports regarding impact of fertilizer industry effluent on the level of AChE activity are very scanty. In this paper, an attempt has been made to investigate the in vitro impact of fertilizer industry effluent upon the levels of AChE activity and protein content in different tissues of non-target aquatic fish, Channa striatus (Bloch). The fish when exposed to three sublethal concentrations (3.5, 4.7, and 7.0%; v/v) of fertilizer industry effluent for short (96 h) and long (15 days) durations registered sharp reduction in the levels of AChE activity (15-75%) and protein (10-71%) in different fish organs. The highest effluent concentration treatment for short or long duration, the fish brain and gills registered significant (P < 0.001) inhibition (64-75%) in the activity of AChE whereas other organs such as muscles, liver, and heart exhibited slightly lower inhibition (40-59%) in enzyme activity. However, kidney of C. striatus was the only organ where very less effect (14-18%) of the effluent was observed on the activity of AChE when the fish were exposed to all the three concentrations of the effluent for both treatment durations. This effluent also induced alterations in the level of protein in different fish organs; in kidney the effect was pronounced only at higher concentrations at both treatment durations. The most affected organs were muscle and gills where in 60-71% reduction in the protein content was recorded due to highest effluent concentration treatment at short or long durations. The results of present study indicated that the fertilizer industry effluents might significantly influence the neurotransmission system and protein turnover in the non-target organisms after exposure even at very low concentrations. Further, the data suggested that the fish AChE could be used as a potential biochemical marker for fertilizer industry effluent pollution in aquatic systems.

Application of oxidative stress indices in natural populations of Perna viridis as biomarker of environmental pollution

Oxidative stress indices were measured in gills and digestive glands of Perna viridis collected from three coastal locations in Goa i.e., Bambolim, Marmugao Harbour and Malim. In addition to lipid peroxidation, the activities of antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase and two non-enzymatic antioxidants (ascorbic acid and reduced glutathione) were investigated in order to understand their variation with respect to pollution status of the sampling locations. We observed a significant increase in lipid peroxidation and antioxidant enzymes of both the tissues at Mormugao Harbour and Malim, suggesting that the animals at these two locations are at higher level of oxidative stress as compared to those at Bambolim. Conversely, low levels of non-enzymatic antioxidants such as ascorbic acid and reduced glutathione, observed at Mormugao Harbour and Malim indicate that the animals may use these compounds to counteract stress in the tissues. This study shows that changes in lipid peroxidation, superoxide dismutase, catalase, glutathione reductase, glutathione S-transferase and reduced glutathione in tissues of P. viridis can be used as molecular biomarkers in environmental monitoring programs.

Evaluation of impairment of DNA integrity in marine gastropods (Cronia contracta) as a biomarker of genotoxic contaminants in coastal water around Goa, West coast of India

The measurement of the impairment of DNA in marine gastropod (Cronia contracta) provides an insight into the genotoxic effects of contaminants on marine organisms along the Goa coast. The impact of genotoxic contaminants on Goan coastal environment was evaluated in terms of the loss of DNA integrity (expressed as the value of 'I') in marine snails with respect to those from the reference site (Palolem) over a period from April 2004 to May 2005 using the technique of alkaline unwinding assay. The DNA integrity in marine snails was found to be significantly damaged at Dona Paula (58%), Vasco (73.5%), and Velsao (48.5%) during the monsoon period (July-August 2004). Similar trend in the loss of DNA integrity in marine gastropods was also detected during the post-monsoon (November-December 2004) and the pre-monsoon (April-May 2005) periods. The low integrities of DNA in marine gastropods at these sites can be attributed to exposure to genotoxic contaminants especially polycyclic aromatic hydrocarbons (PAHs) and toxic heavy metals (Pb, Cd, Cu, Fe, and Mn) prevalent in the marine environment as evident by their accumulation in the tissues of the marine snails inhabiting different sites along the Goa coast. The contaminant-induced DNA strand breaks in marine snails increased significantly at Dona Paula, Vasco, and Velsao clearly indicating the levels of contamination of the sites by genotoxic compounds in those regions. The genotoxic effects of contaminants were further substantiated by detection of the impairment (39%) of DNA integrity in marine snails in a field experiment in which the same species of marine snails (C. contracta) collected from the reference site, Palolem, were deployed at Dona Paula and caged for 25 days for exposure to ambient marine pollutants. The impairment of DNA integrity in marine gastropods along the Goa coast can thus act as a biomarker for marine pollution monitoring of genotoxic contaminants.

Cholinesterase activities in the scallop Pecten jacobaeus: characterization and effects of exposure to aquatic contaminants

Nearshore marine environments of industrialized countries are increasingly threatened by anthropogenic pollution. It is therefore a priority task to investigate the sensitivity of new ecotoxicological warning signals of the occurrence and effects of aquatic pollutants. The main aims of the present study were: 1) to characterize the biochemical properties of ChEs in tissues of the bivalve Pecten jacobaeus, using different specific substrates and selective inhibitors; 2) to measure sensitivity of ChE activities to in vitro exposure to the OPs azamethiphos and DFP and to the heavy metals cadmium and zinc. Our final aim was to carry out a preliminary evaluation of the suitability of ChEs measurement in tissues of the scallop for monitoring marine environmental quality and neurotoxic compounds contamination in the Mediterranean Sea. Responses to specific inhibitors have suggested that ChEs in adductor muscle share many characteristics with vertebrate acetylcholinesterase. Dose-dependent inhibition of ChE was observed in response to in vitro exposure to environmental contaminants such as cadmium and azamethiphos. Sensitivity to zinc and DFP was lower. ChEs in P. jacobaeus might therefore have potential as a sensitive biomarker for monitoring marine pollution. Results of the present study will be useful to focus further experiment of exposure to pollutants under in vivo conditions.

CAPSULE

Cholinesterase activities in scallop Pecten jacobaeus were observed to be sensitive to contaminants in vitro and may therefore have potential as biomarkers for monitoring water pollution.