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Previous observations showed that Trolox, a synthetic analog of vitamin E, widely used as antioxidant standard in a number of bioassays, can exert a pro-oxidant behavior at higher concentrations (>40 µM) on HeLa cells exposed for 24h, producing an isotonic cell shrinkage. A number of cellular events are known to be triggered by oxidative stress, including impairment of ion transport mechanisms and alteration of cell volume homeostasis. This work aims to investigate the possible mechanisms through which Trolox at high concentrations acts on cell volume homeostasis alteration in HeLa cells. The study was carried out by 1) spectrofluorimetric determination of intracellular oxidative stress in cells charged with CM-H2DCFDA, 2) morphometric analysis of cells observed under optical microscopy for cell volume determination, and 3) spectrofluorimetric and confocal analysis of cells charged with Annexin V/Propidium Iodide for apoptotic induction. HeLa cells exposed for 24h to high Trolox concentrations showed a significant dose-dependent isotonic reduction of cell volume associated to intracellular oxidative stress. The observed isotonic shrinkage was accompanied by apoptosis induction, as demonstrated by Annexin V/Propidium Iodide and was ascribed to Apoptotic Volume Decrease (AVD). The isotonic shrinkage appearance was demonstrated to occur early (after 2h) during the exposure to high Trolox concentrations. It was completely inhibited by pretreatment of the cells with a Cl- channel blocker SITS (0.5 mM). These results indicate that treatment of HeLa cells with high Trolox concentrations induces the activation of volume-regulatory Cl- channels, most likely by an increase in endogenous ROS production, which in turn is able to generate AVD.

Atmospheric particulate matter is a concern in most of the European towns because it has potential negative effects on human health (Davidson et al., 2005; Lelieveld et al., 2015). Although the toxic effects of PM have been correlated with some of its chemical and physical properties, the toxicity mechanisms are not yet fully known. Different in vitro toxicological tests are often necessary to characterise potential health effects and, often, it is found significant correlation only among a few of the possible tests. In addition, contrasting results could be obtained comparing in vitro tests with acellular assays like those used to determine oxidative potential (Steenhof et al., 2011; Van Den Heuvel et al., 2018). The aim of the work was to study the oxidative potential (OP) of PM10, determined with the acellular DTT assay, in relationship with its ecotoxicological and cytotoxicological potential. The study was carried out on aqueous extracts of 10 samples of airborne PM10 randomly selected among the samples collected between 16/09/2017 and 25/12/2017. Samples were collected using a low-volume (2.3 m3 /h) sampler (SWAM, Fai Instruments srl) on 47 mm quartz fibre filters (Whatman) pre-fired at 700 °C for 2 hours in order to reduce contamination. Samples were exposed for 24 hours (starting at midnight) at the Environmental-Climate Observatory of ISAC-CNR in Lecce (Southern Italy), regional station of the Global Atmosphere Watch (GAW) network, characterised as an urban background site (Cesari et al., 2018). The aqueous extraction was performed in an ultrasonic bath for 80 min using 10 ml Milli-Q water. The ecotoxicological potential of PM10 was assessed by the bioluminescence inhibition assay based on the Gram-negative non-pathogenic bacterium Vibrio fischeri (Microtox® test), which physiologically emits light as a results of its metabolic activity. The natural bioluminescence of V. fisheri is inhibited by the exposure to a number of chemical pollutants, including organic and inorganic compounds (Abbass et al., 2018). Different exposure times (5, 15, and 30 mins) were used and inhibition results, obtained with five repetitions, are reported as a net effect corrected using field blanks. The cytotoxicological potential of PM10 was assessed on the same extracts by the MTT assay on the cell line A549. The MTT assay is based on a colorimetric reaction dependent on mitochondrial respiration of the cells and indirectly allows assessing the cellular energy capacity of a cell (Stockert et al., 2012). The MTT assay was applied to the A549 cell line, representative of the alveolar type II pneumocytes of the human lung (Foster et al., 1998). Cell mortality after 24h exposition is evaluated, in relative terms, considering the net effect of PM10 using field blanks for correction. Six repetitions were done. The water-soluble fraction of PM10 was also used for the analysis of the OP, performed with the dithiothreitol assay (DTT), a surrogate for cellular antioxidants, which analyses the rate of DTT depletion catalysed by chemical species present in the PM (Chirizzi et al., 2017). An aliquot of the extracts was diluted with deionised water (1:4 factor). Diluted samples were incubated at 37 °C with DTT (0.1 mM) in 0.1 M potassium phosphate buffer at pH 7.4 for times varying from 5 to 90 min. At designated times (specifically at 5, 10, 15, 20, 30, 45, 60, and 90 min) an aliquot of incubation mixture was picked up and 10% trichloroacetic acid was added to stop the reaction. Then, this reaction mixture was mixed with a solution containing 10 mM DTNB. The concentration of the formed 5-mercapto-2-nitrobenzoic acid was measured by its optical density absorption at 412 nm using a Eon BioTek Microplate Spectrophotometer. The consumption of DTT over time was determined through the linear fitting of the absorbance with the time in which it was made the withdrawal. The DTT depletion rate was used to determine OP values as DTT-activity 21 normalized in terms of sampled air volume (OPV) or in terms of mass of collected aerosols (OPM). The OPV and OPM values were comparable with previous measurements in this area or in other Italian towns (Chirizzi et al., 2017). In all the 10 samples analysed a significant inhibition of the Vibrio fisheri bioluminescence was observed as a results of the exposure of bacteria to the undiluted extracts for 5, 15 and 30 min, suggesting the presence in the PM10 of components able to induce an ecotoxic effect. Four samples (samples n. 2,3,4, and 7) showed a % of inhibition ranging from 30% to 50%, ascribable to a slight toxic effect, while six samples (samples 1,5,6, 8,9, and 10) showed a % of inhibition above 50% after 30 min exposure, suggesting the presence of a toxic effect. The correlation analysis between the sampled mass and the Vibrio fisheri bioluminescence inhibition showed a significant positive correlation (p

Carbonic anhydrase (CA) is a ubiquitous metalloenzyme involved in a number of physiological processes. Its sensitivity to chemical pollutants has been recently recognized. The work was aimed to study the CA sensitivity to metal exposure in the digestive gland of the model organism Mytilus galloprovincialis under in vitro, in vivo and in field conditions, with reference to the functional involvement of CA in the lysosomal response to pollutant exposure. The study was carried out by immunofluorescence confocal microscopy, electrometric assay of CA activity, spectrofluorimetric and confocal analysis of the lysosomal system. Under in vitro exposure to CdCl2 or CuCl2, CA activity was dose-dependently inhibited with an IC50 of 8.7 10-5M for copper and 1.1 10-3M for cadmium. On the other hand, under in vivo chronic exposure to CuCl2 (0.3 10-6 M) or CdCl2 (0.54 10-6 M) for 14 days, CA showed a significant upregulation, paralleled by the increased fluorescence of LysoSensor green charged cells, indicative of lysosome proliferation/increase in size. The metal induced lysosomal activation was prevented by the in vivo exposure to the specific CA inhibitor acetazolamide, demonstrating a key role of CA in the pollutant induced lysosomal activation. The response of CA upregulation paralleled by lysosomal activation was validated in the field by an active biomonitoring approach in coastal marine sites interested by metal contamination. In conclusion, data showed the complexity and multi-aspect nature of the CA sensitivity to metals, which can be CA inhibitors at higher concentrations and modulator of CA expression at lower concentrations typical of chronic exposure. In this condition CA upregulation can be functional to the prolonged increased requirement of H+ under lysosomal activation.

Branchiomma boholense is a sabellid polychaete considered highly invasive in the Mediterranean Sea as in few years it was able to expand its distribution range across the entire basin. Along the Italian coasts, this species has also been reported in venting areas near Castello Aragonese (Ischia Island) where CO2 emissions lower the seawater pH up to 6.00 values. The aim of this study was to test the physiological response of B. boholense to the decrease of seawater pH, measuring the activity of carbonic anhydrase (CA), a zinc metalloenzyme known to be affected by low pH conditions in other taxa. A transplant experiment employing the CO2 vents of Ischia was carried out. Worms were collected from a control pH area in the Mar Grande of Taranto and transplanted in two areas around Ischia, a control and a high pCO2 area. Three sites per area were utilized. Thirty individuals per site were exposed in plastic cages for 30 days. CA activity was measured electrometrically on the tissue homogenate of each specimen. Results of the ANOVA analysis on translocated worms showed no significant differences in CA activity either between individuals exposed to control and acidified conditions, nor among specimens transplanted in different sites within the same area. However, organisms exposed to the acidified area showed a decrease of their wet weight of about 20% compared to animals translocated in control sites. Moreover, CA activity was also investigated in specimens native from normal (Taranto) and high pCO2 environments (Ischia). The analysis of their wet weight revealed a marked decrease (by about 70%) in worms from the acidified area with respect to control animals. Interestingly, protein tissue content showed a significant (50%) increase in specimens native from the vent system with respect to the Taranto control area. Therefore, significant differences in CA activity (U/g wet weight) between specimens naturally exposed to normal and acidified conditions were also observed, with individuals living in acidified environments showing doubled values of enzymatic activity. The results of this study demonstrated that B. boholense is inclined to maintain a great homeostatic capacity when exposed to low pH. However, a marked decrease in body weight was observed under chronic exposure to high pCO2, suggesting the need of further studies to understand if the maintenance of a homeostatic balance come at the expense of other energy demanding physiological processes

Carbonic anhydrase (CA) is a ubiquitous metalloenzyme involved in a number of physiological processes including respiration, pH homeostasis, electrolyte transport, calcification, biosynthetic reactions. The aim of this work was to explore a novel functional role of CA in animals: its involvement in the lysosomal system response to metal exposure. Mytilus galloprovincialis digestive gland was used as experimental model. The in vivo exposure of mussels to CdCl2 was able to evoke the induction of digestive gland CA. This response was paralleled by the activation of the lysosomal compartment (proliferation and/or increase in size of lysosomes), as assessed on LysoSensor Green marked cells by confocal microscopy and spectrofluorimetric analysis. When mussels were in vivo exposed to acetazolamide, specific CA inhibitor, the acidification of the lysosomal compartment was prevented. Moreover, during the co-exposure to cadmium and acetazolamide, the cadmium induced activation of the lysosomal compartment was completely inhibited. In conclusion, our results demonstrated in vivo the physiological contribution of CA to the acidification of the lysosomal compartment in digestive gland and its involvement in the lysosomal activation following cadmium exposure. CA induction following cadmium exposure could physiologically sustain a prolonged increased requirement of H+ for supporting lysosomal acidification during lysosomal activation.

Recently a dual behavior (antioxidant vs pro-oxidant) of some bioactive molecules has emerged. Trolox, a synthetic analog of vitamin E, widely used as antioxidant standard in a number of bioassays, in the presence of peroxidase/H2O2 is known to induce lipid peroxidation. The aim of the present study was to investigate the antioxidant/pro-oxidant properties of Trolox in HeLa cells in relationship to cell volume homeostasis alteration and cytotoxicity. The study was carried out by spectrofluorimetric analysis of cells charged with the ROS-sensitive probe CM-H2DCFDA, morphometric analysis of the cells and MTT test. When the cells were exposed (24h) to increasing Trolox concentrations (from 2.5 to 160 µM) and then charged with CM-H2DCFDA, an antioxidant effect on the endogenous ROS production was observed at low concentrations, but a marked pro-oxidant behavior was evident at higher concentrations. The same dose-dependent dual behavior was observed also in the presence of an exogenous oxidative challenge (H2O2). At higher concentrations Trolox was able to induce a dose-dependent isotonic reduction of cell size in parallel to a reduction of cell vitality. In conclusion, our study demonstrated the dose-dependent antioxidant/pro-oxidant behavior of Trolox in HeLa cells. The pro-oxidant effect was associated to an isotonic cell shrinkage, probable early signal of an apoptotic process ascribable to Apoptotic Volume Decrease, suggesting an alteration effect on the membrane transport mechanisms involved in cell volume homeostasis

Branchiomma bairdi is a sabellid polychaete native of the Caribbean Sea and recently introduced in the Mediterranean Sea where the species’s range has rapidly expanded as a consequence of its ability to colonize different environments and substrates. The species has also been reported around Ischia (Naples, Italy), a volcanic Island characterized by numerous submerged CO2 vent systems. In this regard the species occurs at the Castello vent system where intense CO2 emissions along the rocky reef lower the seawater pH up to mean values >7.4. In order to investigate the physiological response of B. bairdi to seawater acidification, worms were collected from the Mar Grande of Taranto, a non-acidified area in the south of Italy, and transported to Ischia in order to perform a transplant experiment into naturally acidified conditions. Three acidified plots were selected around the Castello vent’s area (A4, A5 on the south side; A6 on the north side), and three plots on a control area located at S. Pietro point (mean pH 8.12), approx 4 km from the Castello (C1, C2, C3). Thirty individuals per plot (90 per treatment) were exposed inside plastic cages, to both acidified and control conditions for 30 days. Cages were monitored and pH and temperature were measured in each plot approx. every four days until the end of the experiment. In addition, some individuals sampled both in Taranto and the Castello acidified area were frozen immediately after collection and used as a background condition test. The physiological response of B. bairdi to the acidified treatment was inferred measuring the activity of carbonic anhydrase (CA) a zinc metalloenzyme involved in a wide variety of physiological processes in animals. CA enzymatic activity was measured by electrometric method on the whole body homogenate of the species. CA activity data from the in vivo exposure experiment were analyzed by two-way ANOVA. No significant differences (p>0.05) in CA activity between acidified and control treatment were observed both in the transplanted and background worms, suggesting that this invasive species shows high physiological plasticity and it is well acclimatized to the acidified conditions of the Castello vent system.

The gastrointestinal tract is exposed to a number of pro-oxidant conditions and several gastrointestinal diseases are related to oxidative stress. The preservation of the gastrointestinal redox balance is of pivotal importance for the health status of the organism. It depends on a dynamic system involving antioxidant enzymes, as well as non-enzymatic molecules some of which derive from the diet. This work focuses on the intestinal epithelium and its aim was to explore the intracellular ROS scavenging activity of intracellularly absorbed food antioxidants. Freshly isolated intestinal explants obtained from different experimental animal models were used. They retain the functional and morphological characteristics of the epithelium in vivo. In situ confocal detection on CM-H2DCFDA charged explants experimentally exposed to pro-oxidant conditions was applied. Phenolic phytochemicals, such as hydroxytirosol or anthocyanins, commonly found in the Mediterranean diet, were demonstrated in surface enterocytes to cross the plasma membrane and exert a direct intracellular antioxidant activity. The effect was dose and time dependent and was compared with Trolox, synthetic analog of vitamin E. In conclusion, the gastrointestinal epithelium represents the first interface for the intracellular ROS scavenging activity of food antioxidants, and as such it can benefit directly and earlier than other body tissues of the protective action of food antioxidants against pro-oxidant conditions.

Chloride transport is involved in a wide variety of cellular functions, including regulation of the membrane potential, cell volume, acid base balance, and epithelial fluid absorption and secretion. Alterations in chloride transport mechanisms are related to a number of physio-pathological conditions. The aim of this study was to investigate chloride transport across the plasma membrane of cervical cancer cell lines (HeLa), relying on the halide binding properties of a green (GFP) fluorescent protein variant (YFP) that, if halide complexed, decreases the basal fluorescence intensity. The fluorescence changes of HeLa cells expressing YFP was analyzed by confocal and spectrofluorometric analysis. Our results highlights the presence of a transmembrane halide transport through fluorescence quenching when the transfected cells were exposed to NaI, used as a surrogate ion, under isotonic conditions. This quenching was inhibited by bumetanide, a specific inhibitor of Na+-K+-2Cl- cotransporter, demonstrating the role of such transporter in intracellular halide absorption and allowing cellular fluorescence assay for a functional study of Na+-K+-2Cl-. The kinetic parameters of the transporter were quantified. The present work provides an alternative approach for the measurement and characterization of Cl- and halide transport in living cells expressing YFP-H148Q/I152L based on a non-invasive analysis method.

Colon epithelium is exposed to oxidative stress conditions via exogenous and endogenous routes and a number of colon diseases are associated with the imbalance of the cellular redox system. The aim of the present work was to study the intracellular antioxidant activity of red grape polyphenolic extracts on superficial enterocytes experimentally exposed to prooxidant conditions. In situ confocal microscopy observation on CM-H2DCFDA charged explants exposed to H2O2 (5, 10, and 15min) was performed. First, the ability of the experimental set up to detect intracellular ROS scavenging activity by intracellularly absorbed antioxidants was demonstrated by a dose-response inhibition of the H2O2 induced intracellular probe fluorescence following pre-incubation with Trolox, synthetic analog of vitamin E. Then, the explants were incubated with grape skin polyphenolic extracts for 1 h producing a significant decrease of the H2O2 induced fluorescence. This effect was more pronounced following 15 min H2O2 exposure with respect to 5 min and it was also more evident for extracts obtained from mature grapes, which showed an increased ORAC value and qualitative peculiarities in the polyphenolic composition. Results demonstrated that red grape polyphenolic extracts are able to exert an intracellular antioxidant activity on superficial colonocytes, inducing a protection action against pro-oxidant condition. Extracts obtained from mature grapes showed an increased protective activity

Lysosomes are intracellular organelles with an acidic internal pH maintained by a V-ATPase H+ pump. Lysosomal reactions (alterations in lysosomal number and size and lysosomal destabilization) are involved in a number of physiological responses, including xenobiotic and heavy metal sequestration and detoxification. The aim of the study was to investigate the role of carbonic anhydrase, an ubiquitous enzyme catalyzing the hydration of CO2 to HCO2- and H+, in the lysosomal response to heavy metal exposure by using mussel (Mytilus galloprovincialis) digestive cells, characterized by a well developed lysosomal system, as experimental model. CdCl2 was used as reference toxicant. A novel microplate fluorimetric assay was developed on digestive cells in suspension, charged with the fluorescent acidotropic probe Lysosensor™ Green DND-189, for quantitating the number of lysosomes and their pH. In parallel, single cell analysis was performed by confocal microscopy. Digestive cells from Cd exposed animals showed a time and dose dependent increase of the probe fluorescence, suggesting a proliferation of the lysosomal compartment and decrease of the internal pH. This was confirmed by single cell confocal analysis. In animals in vivo exposed to acetazolamide, specific inhibitor of carbonic anhydrase, the metal induced fluorescence increase was dramatically inhibited. In conclusion, results indicate a key role of carbonic anhydrase in the lysosomal responses to metal exposure.

Biomarkers of chemical contamination were measured in M. galloprovincialis sampled in Mar Piccolo of Taranto in order to evaluate the potential ecotoxicological risk in this area exposed to industrial and urban impact. The analysis of a new potential biomarker, the enzymatic activity of carbonic anhydrase, was included in the biomarkers battery utilized and results obtained suggest its applicability in a multimarker approach.

Aim: Carbonic anhydrase is a zinc metalloenzyme catalysing the reversible hydration of CO2. Its activity is virtually ubiquitous in nature and is involved in a wide variety of physiological processes. The aim of the present work was to study the in vitro and in vivo sensitivity of CA to chemical pollutants in Mytilus galloprovincialis, widely used as sentinel organism in marine pollution biomonitoring, with the aim to develop a new biomarker of exposure/effect to chemical contamination. Methods: CA activity was measured applying a simple and low cost electrometric method. Briefly, enzymatic activity units were calculated from the rate of H+ production in the reaction mixture (where CO2 as substrate was present) against a blank containing the specific CA inhibitor acetazolamide. Results: As first step, we demonstrated the presence of a significant CA activity in M. galloprovincialis tissues and its sensitivity to in vitro exposure to several heavy metals. As second step, we demonstrated a significant tissue-specific alteration of CA activity following in vivo Cadmium exposure, with a significant increase in the digestive gland. As third step, immunoprecipitation and western blot analysis on mussel digestive gland revealed a protein that immunoreacts with the antibody at a molecular mass of approximate 42 kDa (the sequencing analysis is in progress). Interestingly the 42 KDa band, ascribed to CA, appeared strongly increased in the digestive gland of cadmium exposed mussel (14 day exposure), thus leading to an induction of CA expression in accordance with the observed enzymatic activity increase. As final step, the laboratory resulted was validated with field experiments. Conclusion: Obtained results represent a good starting point for future potential biomarker application of the CA activity in the sentinel organism M. galloprovincialis.

Carbonic anhydrase (CA; EC 4.2.1.1) is a zinc metalloenzyme catalysing the reversible hydration of CO2. Its activity is virtually ubiquitous in nature and is envolved in a wide variety of physiological processes. Until today, fourteen CA isozymes (CA I-XIV) were characterised in animals, plants and certain bacteria. Pollutants like heavy metals are considered strong CA activity inhibitors, however few works have studied the sensitivity of CA from aquatic organisms to cadmium and comparatively much less studies on invertebrates are available. In Mytilus galloprovincialis (widely used in marine pollution monitoring programmes as sentinel organisms), we previously demonstrated a significant tissue-specific alteration of CA activity following in vivo cadmium (Cd) exposure, with a significant increase in the digestive gland. In order to establish if protein expression was involved in the observed metal activation of the enzymatic activity, in the present work immuno-precipitation and western blot analysis were applied to the tissue extract of control and Cd exposed mussels. Mussels were exposed to 1.8 µM CdCl2 for 14 days. Digestive gland CA activity was measured applying a simple and low cost electrometric method (Caricato et al., ESCPB Congress, 2003). Immunoprecipitation and western blot analysis (using the polyclonal anti-Carbonic Anhydrase II antibody) revealed in mussel digestive gland a protein that immunoreacts with the antibody at a molecular mass of approximate 42 kDa (the sequencing analysis is in progress). 42 kDa corresponds to the molecular weight of native CA VI (Parkkila S. et al., 1997), whose presence in invertebrates has never been revealed before. Interestingly the 42 KDa band, ascribed to CA, appeared strongly increased in the digestive gland of mussel after 14 day exposure, thus leading to a induction of CA expression in accordance with the observed enzymatic activity increase. To our knowledge this is the first time that Cd inducible CA activity and expression are reported. In conclusion, obtained results represent a good starting point for future potential biomarker application of the CA activity in the sentinel organism M. galloprovincialis.

Carbonic anhydrase (CA; EC 4.2.1.1) is a zinc metalloenzyme catalysing the reversible hydration of CO2. Its activity is virtually ubiquitous in nature and is envolved in a wide variety of physiological processes. Until today, fourteen CA isozymes (CA I-XIV) were characterised in animals, plants and certain bacteria. Pollutants like heavy metals are considered strong CA activity inhibitors, however few works have studied the sensitivity of CA from aquatic organisms to cadmium and comparatively much less studies on invertebrates are available. In Mytilus galloprovincialis (widely used in marine pollution monitoring programmes as sentinel organisms), we previously demonstrated a significant tissue-specific alteration of CA activity following in vivo cadmium (Cd) exposure, with a significant increase in the digestive gland. In order to establish if protein expression was involved in the observed metal activation of the enzymatic activity, in the present work immuno-precipitation and western blot analysis were applied to the tissue extract of control and Cd exposed mussels. Mussels were exposed to 1.8 µM CdCl2 for 14 days. Digestive gland CA activity was measured applying a simple and low cost electrometric method (Caricato et al., ESCPB Congress, 2003). Immunoprecipitation and western blot analysis (using the polyclonal anti-Carbonic Anhydrase II antibody) revealed in mussel digestive gland a protein that immunoreacts with the antibody at a molecular mass of approximate 42 kDa (the sequencing analysis is in progress). 42 kDa corresponds to the molecular weight of native CA VI (Parkkila S. et al., 1997), whose presence in invertebrates has never been revealed before. Interestingly the 42 KDa band, ascribed to CA, appeared strongly increased in the digestive gland of mussel after 14 day exposure, thus leading to a induction of CA expression in accordance with the observed enzymatic activity increase. To our knowledge this is the first time that Cd inducible CA activity and expression are reported. In conclusion, obtained results represent a good starting point for future potential biomarker application of the CA activity in the sentinel organism M. galloprovincialis.

As specific molecular target of organophosphate and carbammate pesticides, acetylcholinesterase activity and its inhibition has been early recognized to be a human biological marker of pesticide poisoning, but in the last two decades the interest for acetylcholinesterase has increased a lot in the ecotoxicological field; its determination has become a tool for monitoring environmental contamination and organismal exposure to those compounds in the biota. Furthermore its use in different phyla, either vertebrates or invertebrates makes acetylcholinesterase a particularly versatile biomarker that can be used to investigate pollutant effects at many trophic levels and in different environments.

INTRODUCTION: Bivalve mollusks and specially mussels are widely used as sentinel organisms in marine environmental quality assessment (Goldberg et al., 1978). Pollutant exposure biological responses (i.e. biomarkers) are increasingly investigated in mussel tissues and their measurements largely used in marine environmental monitoring. Mussels emocytes play very important role in mollusk physiology, mainly in the internal defense, and used for general biomarker determination such as lysosomal membrane stability. The aim of the present work was to investigate possible morphological alterations in Mytilus galloprovincialis haemocytes, in particular granulocytes, which represent the main defense system of the organisms, following pollutant exposure either in laboratory or in field conditions. MATERIAL AND METHODS: As regards laboratory exposure, an homogeneous stock of M. galloprovincialis was divided in two groups: the control one and the other one exposed to cadmium chloride (600 g l-1) for 14 days. At time 0, 3, 7 and 14 days haemolymph samples were collected. As regards field exposure an homogeneous stock of M. galloprovincialis was divided in two caged groups, translocated in a reference and in a polluted sites respectively. After 30 days exposure haemolymph samples were collected from both groups. M. galloprovincialis haemolymph samples were stained with Diff Quick (Dade Behring, Newark -USA), a rapid staining solution kit, to date utilized in the diagnostic field (Jorundsson et al, 1999). Diff Quick allowed the staining of haemolymph cells, in particular granulocytes, whose morphology including cytoplasm, nucleus and acidophilic granules appeared clearly defined. Diff Quick stained granulocytes were investigated by optical microscopy and image analysis. RESULTS AND DISCUSSION: Granulocytes from cadmium exposed mussels showed a significant increase of their surface, suggesting an activation of the granulocytes defence system in this organism after pollutant exposure. Moreover, a significant decrease of the perimeter/area ratio of granulocytes bidimentional images was observed, probably due to a cadmium induced reduction of the microfilament and microspine number. Interestingly, these findings were confirmed by results obtained with granulocytes from in field exposed mussels, which also showed a significant increase in their acidophilic granules. Results obtained suggest that the observed cytological alterations in mussel granulocytes can be proposed as potential biomarker of chemical stress exposure suitable to be used in a biomarker battery in marine environmental monitoring programmes. Moreover, the Diff Quick staining protocol proposed for mussel morphological alteration measurements, being rapid, sensitive, inexpensive and easy to be used, responds to the needs of the field biomonitoring application.

Carbonic anhydrase (CA) is a metalloenzyme catalizing the reversible idratation of CO2 in H+ and HCO3-. It is an ubiquitous enzyme in bacteria, plant and animal kingdoms, playing a fundamental role in a number of physiolgical processes. Previous studies demonstrated the sensitivity of carbonic anhydrase activity to dichlorodiphenyl-dichloro-ethane (DDT) exposure in birds [1] and to cadmium exposure in teleost [2]. The aim of the present work was to investigate the in vitro sensitivity of carbonic anhydrase activity to several organic and inorganic chemical compounds, in order to standardize a carbonic anhydrase based bioanalytical method available for monitoring environmental samples. Commercial available CA isozyme II from bovine erythrocytes was utilized for the in vitro bioassay. CA activity was determined by a modification of electrometric method previously described by Wilbur and Anderson (J. Biol. Chem., 257: 12056-12059, 1948): briefly CA activity units were calculated from the rate of H+ production in the reaction mixture (where CO2 as substrate was present) against a blank containing the specific CA inhibitor acetazolamide. [H+] variation in the reaction mixture was followed at 0°C using a Mettler Delta 350 pH-meter. In our experimental set up bovin CA activity was significantly inhibited by nanomolar concentration of heavy metals (Cd, Cu and Hg), organochlorate compounds and carbammate pesticides, showing a dose-response behaviour. Carbonic anhydrase in vitro bioassay can represent a novel tool for rapid and low cost understanding of the toxicity of environmental samples, of bioavailability of pollutants in evironmental matrices, and of their additive or synergistic biological effects when present in mixtures.

Acetylcholinesterase (AChE) is a key enzyme in the nervous system. It terminates nerve impulses by catalysing the hydrolysis of neurotransmitter acetylcholine. As a specific molecular target of organophosphate and carbamate pesticides, acetylcholinesterase activity and its inhibition has been early recognized to be a human biological marker of pesticide poisoning. Measurement of AChE inhibition has been increasingly used in the last two decades as a biomarker of effect on nervous system following exposure to organophosphate and carbamate pesticides in occupational and environmental medicine. The success of this biomarker arises from the fact that it meets a number of characteristics necessary for the successful application of a biological response as biomarker in human biomonitoring: the response is easy to measure, it shows a dose-dependent behavior to pollutant exposure, it is sensitive, and it exhibits a link to health adverse effects. The aim of this work is to review and discuss the recent findings about acetylcholinesterase, including its sensitivity to other pollutants and the expression of different splice variants. These insights open new perspective for the future use of this biomarker in environmental and occupational human health monitoring.

Heavy metals are known to in vitro inhibit carbonic anhydrase (CA) activity in a variety of organisms; however, little is known about their in vivo effects on the activity and the expression of this metalloenzyme. The aim of this work was to investigate the in vitro and in vivo sensitivity to cadmium of CA in the digestive gland of Mytilus galloprovincialis. CA activity and protein expression (apparent molecular mass of about 28 kDa) were demonstrated in mussel digestive gland for the first time. CA activity showed week sensitivity to in vitro cadmium exposure, while it was significantly increased (about 40%) following two weeks in vivo exposure. In parallel, CA protein expression appeared significantly enhanced as demonstrated by Western blotting. Laboratory experimental results were confirmed by a field experiment. Mussels exposed for 30 days to an impacted site showed a significant increase of the CA activity and protein expression with respect to animals exposed to the control site in parallel to the increase of the metallothionein tissutal concentration. In conclusion in the present work for the first time CA activity and protein expression have been demonstrated to be enhanced by the exposure to the trace element cadmium in animals.