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ABSTRACT: Copper is used in treatment mixtures to control fungal diseases in vineyards. Its concentrations are relatively high in some aquatic ecosystems, and the main problem observed in this study was the antioxidant stress induced by this heavy metal. Copper toxicologic effects in aquatic organisms have prompted the demand for alternative use of low-toxicity molecules in culture treatments. Chitosan is a polymer with antifungal property similar to copper and may be an interesting biopesticide. Thus, it is necessary to investigate the potential toxicity of chitosan for aquatic animal health, either alone or in conjunction with copper. In this study, carp were exposed to two sublethal chitosan concentrations (75 and 150 mg/L) or to two sublethal copper concentrations (0.1 and 0.25 mg/L) or to a mixture of chitosan plus copper (75 mg/L and 0.1 mg/L, respectively). The results of the present study show that exposure to copper at environmentally realistic levels or to chitosan at sublethal concentrations may significantly stimulate various aspects of immune functions in carp such as nonspecific cellular immunity, represented by total immunoglobulin level, ceruloplasmin activity, and oxidative activity of phagocytes. This acute-phase inflammatory response induced separately by the two treatments was not observed, especially on phagocyte oxidative activity, when carp were exposed to the copper-chitosan mixture. This fact could be explained by a possible chelation of copper by chitosan decreasing the biodisponibility of the two products for immune cells. Thus, the immunotoxicologic impact of copper and chitosan on fish immune response would be less pronounced with the combined treatments than with separate treatments in an aquatic environment.
Archives of Environmental Contamination and Toxicology 11/2004; 47(3):370-8. · 1.93 Impact Factor
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ABSTRACT: We evaluated the potential of chitosan both to stimulate plant development and to induce protection from Botrytis cinerea in Vitis vinifera L. plantlets. The presence of 1.75% (v/v) chitogel in the culture medium was the optimal concentration for in vitro grapevine plantlet growth, as determined by measurements on enhancement of root and shoot biomass. Photosynthesis and related parameters were also stimulated in chitogel-treated plantlets. Chitogel reduced the development of Botrytis cinerea and induced cytological alterations to the pathogen. When challenged with the fungus, a significant decrease in disease incidence was observed in plants growing on medium supplemented with chitogel. Furthermore, exogenous foliar applications of chitogel to plantlets growing on chitogel-free medium sensitized them so as to be protected against Botrytis cinerea attack. Our results indicate that chitogel can be used in the vineyard as a means to attain protection against Botrytis cinerea and that its application may counteract the wide use of chemical pesticides.
Plant Cell Reports 04/2004; 22(8):608-14. · 2.27 Impact Factor
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ABSTRACT: Metallothioneins (MTs) are low-molecular-weight proteins mainly involved in metal ion detoxification. Recently it has been demonstrated that MTs participate in several cellular functions such as regulation of growth and antioxidative defenses. Moreover, pesticides can induce their synthesis. The aim of the current work was to determine the effects of isoproturon, either pure or formulated as Matin (suspension containing an isoproturon concentration of 500 g. L(-1)), on the metallothionein and total protein contents of the aquatic worm Tubifex tubifex. MT levels in exposed worms increased significantly after 7 and 15 days of exposure to a concentration of the herbicide of 50 mg. L(-1). Isoproturon reduced the metal (Cu, Zn, and Cd) content of metallothioneins, and it also increased the total protein content of the worms. These results suggest that MT induction may not be considered a specific biomarker of metal exposure but that it can be used as a nonspecific biomarker of the effect of isoproturon effect in aquatic worms.
Environmental Toxicology 03/2004; 19(1):88-93. · 2.41 Impact Factor
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ABSTRACT: Increased antioxidant enzymatic activities were observed in carp parasitised by Ptychobothrium sp. when compared with healthy fish. This antioxidant response could contribute to neutralise the oxidative stress normally induced by parasitism.
Fish & Shellfish Immunology 12/2003; 15(5):467-71. · 3.32 Impact Factor
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ABSTRACT: Metallothioneins (MTs), are low molecular weight proteins, mainly involved in metal ion detoxification. Recently it has been demonstrated that MTs participate in several cellular functions such as regulation of growth, and anti-oxidative defenses. Moreover, pesticides can induce their synthesis. The aim of the current work was to determine the effects of isoproturon either pure or formulated as Matin (suspension containing 500 g x l(-1) isoproturon) on the metallothionein and total protein content of the aquatic worm Tubifex tubifex. MT levels in exposed worms increased significantly after 7 and 15 days of exposure to 50 mg x l(-1) of herbicide. Isoproturon reduced metal (Cu, Zn, and Cd) content of metallothioneins, and it also increased total protein content of the worms. The results suggest that MT induction may not be considered as a specific biomarker of metal exposure but it can be used as a non specific biomarker of isoproturon effect in the worm.
Communications in agricultural and applied biological sciences 02/2003; 68(4 Pt B):759-70.
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ABSTRACT: The effects on the photosynthetic process of copper and pesticides, used in vineyards, and their combinations, were investigated by measuring different chlorophyll fluorescence parameters in Lemna minor. Cu and flumioxazin had a severe impact on duckweed since a decrease in their photosynthetic capacity was detected after 24h of exposure to 200 and 1 microg.L(-1), respectively. However, fungicides used to control Botrytis cinerea (procymidone, pyrimethanil, and fludioxonil) seem to have no marked effects on duckweed even at very high concentrations (50 mg.L(-1)). Analysis of the combinations between copper (200 microg.L(-1)) and pesticides revealed different patterns of response: a synergistic effect was observed when Cu(2+) was added to flumioxazin (1 microg.L(-1)). In contrast, an antagonism was detected when duckweed was exposed to a mixture of Cu(2+) and fludioxonil or procymidone. However, these interactions always tended toward additivity when pesticide concentrations increased. Additivity was also observed for the Cu(2+)-pyrimethanil mixture at each fungicide concentration.
Ecotoxicology and Environmental Safety 12/2002; 53(3):439-45. · 2.29 Impact Factor
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ABSTRACT: An increased antioxidant response (catalase, glutathione S-transferase (GST) and glutathione reductase (GRd) activities in liver and GST activity in head kidney) was observed in carp parasitized by Ptychobothrium sp. compared to healthy fish. In case of a copper contamination of these fish, the decrease in enzymatic activities observed was less pronounced in parasitized than in healthy carp.
Biochimica et Biophysica Acta 11/2002; 1573(1):4-8. · 4.66 Impact Factor
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Bulletin of Environmental Contamination and Toxicology 07/2002; 68(6):817-23. · 1.02 Impact Factor
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ABSTRACT: Earthworms (Lumbricus terrestris L.) were exposed to endosulfan and aldicarb for 2, 7, and 15 days and lethal concentrations were determined. Worms were then exposed to these concentrations (LC10, LC25, and LC50) of endosulfan and (LC10 and LC25) of aldicarb. Growth rate, total protein content, and insecticide residues were determined. Aldicarb was more toxic than endosulfan and both insecticides caused a significant reduction of growth rate and total protein content of earthworms. Residues remaining in the soil after 2 to 15 days ranged between 37.75% and 68.54% of applied concentration for endosulfan and between 10.13% and 67.71% of applied concentration for aldicarb. Less than 1% of soil concentration was detected in worms and accumulation was more important in the case of endosulfan. This study proposes the use of growth rate and total protein content as biomarkers for contamination by endosulfan and aldicarb.
Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen) 02/2002; 67(2):59-68.
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ABSTRACT: This study was conducted to investigate the effects of isoproturon in mature earthworm (Lumbricus terrestris L.) under laboratory condition. Earthworms were exposed to soils contaminated with different concentrations for various duration. Residues were monitored in soil and earthworms after 7, 15, 30, 45, and 60 days of exposure to different isoproturon concentrations. Acute toxicity of isoproturon was determined together with growth rate and total soluble protein content of worms. These parameters were related to isoproturon concentration in soil and earthworms. No lethal effect of isoproturon was observed even at the highest concentration tested (1.4 g/kg soil) after 60 days after treatment. Residues of isoproturon have caused a significant reduction of the growth rate. Additionally a reduction of total soluble protein was observed in all treated worms. Decrease of isoproturon concentration in soil was slow and depended on herbicide initial concentration. In the worms, it increased during the first 15 days and decreased thereafter. This study is suggesting the use of the growth rate of earthworms as biomarker of exposure to isoproturon.
Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen) 02/2002; 67(2):69-77.
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ABSTRACT: Procymidone, fludioxonil, and pyrimethanil are widely used to control the pathogenic fungus Botrytis cinerea in Champagne's vineyards. These fungicides may end up in surface waters and present potential risks for aquatic vascular plants and algae. Therefore, their toxicity was evaluated on Lemna minor and Scenedesmus acutus in six-day or 48-h tests, respectively. Based on growth and chlorophyll (Chl) content of L. minor and S. acutus cultures, the results showed that the alga was the most sensitive to the fungicides. Among the fungicides, pyrimethanil was the most toxic for L. minor, its nominal IC50 was 46.16 mg l(-1) and that of the other two was >100 mg l(-1). In contrast, pyrimethanil appeared the least toxic for S. acutus at low concentration, nominal IC50 were 22.81, 4.85, and 4.55 mg l(-1) for pyrimethanil, fludioxonil, and procymidone, respectively. Fate of the fungicides in the media was also investigated and acute toxicity of the agrochemicals is discussed in regard to concentration in the culture media. Poor solubility of procymidone and fludioxonil appeared to be partly responsible for the low toxicity of these fungicides. Based on these toxicity data and the concentrations found in ponds collecting vineyard runoff water, these pesticides should not impair the establishment of pioneer plants.
Chemosphere 08/2001; 44(3):467-74. · 3.21 Impact Factor
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ABSTRACT: In an attempt to identify the brain structures that synthesize melatonin and that probably mediate the photoperiodic response of the heteronemertean Myoisophagos lacteus, we utilized immunocytochemical techniques and employed immunoglobulins directed against hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4). This enzyme catalyzes the last step of melatonin biosynthesis. In immunocytochemically treated head sections of Myoisophagos lacteus, antibodies labelled a few cells in the dorsal region of the dorsal cerebral ganglia. Previous studies have shown that melatonin is present both in the brain and eyes of this nemertean species and that melatonin is involved in control of the worm reproduction. Other studies have demonstrated the presence of photoreceptor-like cells in the same region of the worm brain that showed HIOMT immunostaining. Therefore, anatomical findings of the present study, coupled with results of previous works, provide strong evidence that this region of the worm brain houses a photoperiodic receptor involved in melatonin biosynthesis. J. Exp. Zool. 290:156-162, 2001.
Journal of Experimental Zoology 08/2001; 290(2):156-62.
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ABSTRACT: Although Tubifex tubifex (Oligochaeta, Tubificida) has been proposed as a test organism for ecotoxocological studies, very few data concerning sublethal toxicity and bioaccumulation are available on this worm. The aims of this work were to assess the toxicity of cadmium, one of the most toxic metals frequently encountered in polluted areas, on T. tubifex and the ability of the worm to accumulate this metal. Acute toxicity was analyzed by measurement of the 96-h LC(50) and daily survival rates. Results indicated that T. tubifex undergoes an adaptation period to Cd, the duration of which decreases with increasing Cd concentration. The various parameters affecting toxicity are discussed. Sublethal toxicity was studied by scanning electron microscopy. Observations revealed that Cd induced autotomy of the caudal region and mucus production. Autotomy is proposed as a criterion for sublethal toxicity. The results of bioaccumulation studies revealed that Cd is highly and rapidly taken up by the worm, suggesting involvement of efficient detoxification mechanisms. Consequently, the ability to accumulate large amounts of Cd may represent a potential toxicological risk to predators of the worm if Cd is accumulated in bioavailable forms.
Ecotoxicology and Environmental Safety 08/2000; 46(3):246-51. · 2.29 Impact Factor
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ABSTRACT: Metallothioneins (MTs) have important roles in the homeostasis of essential metals and in the detoxication of heavy metals. They also represent a potential indicator of aquatic contamination by metals. Routine methods are needed for MTs quantification in ecotoxicological studies. This paper investigates the possibility to use the spectrofluorescent properties of Cu-MTs for MTs quantification. Cu displacement of metals coordinated to MTs and spectrofluorimetric determination of the obtained Cu-MTs was tested with commercial MTs and Cu2+-induced MTs in roach liver (Rutilus rutilus). Results of this original and simple spectrofluorimetric quantification of MTs presented a good correlation with data obtained with SH quantification, but not with metal summation evaluation of MTs (analysis of Zn, Cu and Cd coordinated to MTs). The three methods showed an clear induction of MTs in roach liver after 7 days of Cu2+ exposure. After 14 days of contamination, a reduction of hepatic MTs content was observable and not correlated to liver recovery. Results show that this low cost spectrofluorimetric method is useful to quantify MTs.
Comparative Biochemistry and Physiology Part C Toxicology & Pharmacology 07/2000; 126(2):113-22. · 2.62 Impact Factor
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ABSTRACT: The photosystem II-herbicide diuron is widely used for weed control in Champagne's vineyards. Its important use and its relative persistence make it of particular interest for ecotoxicological studies. Toxicity of diuron was assessed on Lemna minor L., a representative aquatic macrophyte regularly used for toxicological studies. Toxicity assessments were based on inhibition of growth and total chlorophyll content of L. minor cultures after 7 days. Growth was inhibited and IC(50) and IC(90) were, respectively, 25 and 60 microg l(-1), but chlorophyll content of L. minor increased in response to the herbicide. When diuron was combined with copper, growth inhibition of L. minor depended on the concentrations of both chemicals. For some concentrations, combination of these chemicals resulted in a slight (but non-significant) antagonism. Additivity was observed for all other mixtures. When diuron was combined with folpet, growth and chlorophyll content of L. minor only depended on the concentration of the herbicide. Diuron was also found to prevent the copper-induced decrease of chlorophyll content when it was combined with this metal. A multifactorial model was found more appropriate to characterize interactions between pesticides than Abott's model.
Environmental Pollution 08/1999; 106(1):39-45. · 3.75 Impact Factor
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ABSTRACT: Toxicity of copper and folpet--two fungicides widely used on grape--was evaluated on Lemna minor L., a sensitive aquatic weed regularly used for (eco)toxicological studies. Toxicity assessments were based on inhibition of growth and chlorophyll content of L. minor cultures after 7 days. IC10, IC50, and IC90 were determined for both compounds alone and were respectively, 0.03, 0.16, and 0.95 mg liter-1 for copper and 1.20, 7.50, and > 40 mg liter-1 for folpet. When both compounds were combined, the response of L. minor depended on the initial folpet concentration. Indeed, a slight synergy was observed for 5 mg liter-1 folpet, while at folpet concentrations of 20 to 35 mg liter-1, the two fungicides were antagonists. The antagonism was positively correlated with folpet concentration. Antagonism between Cu and folpet could not be explained by a reduced bioavailability of Cu since concentration of free copper in the mixture did not depend on the presence of folpet. One physiological defense response elicited by copper in plants is an increase in catalase activity. Copper and folpet stimulated catalase activity and changes in the activity of the enzyme could not account for the synergy but possibly for the antagonism. Nevertheless, catalase activity increase significantly after a 24-h exposure to 25 micrograms liter-1 of copper. The use of this property as a rapid and sensitive biomarker to monitor the toxicity of xenobiotics alone or in combination and of environmental water is discussed.
Ecotoxicology and Environmental Safety 07/1998; 40(3):194-200. · 2.29 Impact Factor
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ABSTRACT: The acute toxicity and bioaccumulation (rates, kinetic) of tetravalent platinum in Lumbriculus variegatus under different physicochemical conditions (temperature and total water hardness) were investigated. Increased Pt4+ concentration (from 0.05 to 50 mg/L), exposure (up to 30 days), temperature (from 4 to 20 degrees C) and decreasing water hardness (from 300 to 0 mg/L CaCO3) increased Pt toxicity. The metal accumulated at a constant rate that was concentration, temperature and time dependent. The median lethal concentration (96h LC50) varied greatly from 0.397 mg/L in distilled water to 30 mg/L in the hard water from Champagne. Thus, L. var. can tolerate high levels of Pt. As a result, L. var. can be used in the laboratory to analyze mechanisms of adaptation to the induced stress and in the field as an indicator of Pt pollution.
Archives of Environmental Contamination and Toxicology 08/1996; 31(1):63-7. · 1.93 Impact Factor
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ABSTRACT: Melatonin, a well-known pineal substance implicated in conveying photoperiodic information in vertebrates, appears to be present as well in the eyes and brain of the nemertine worm: Lineus lacteus. The nyctohemeral rhythm was studied, too. The identification of melatonin in this new invertebrate species corroborates our hypothesis that it may be an evolutionarily conserved molecule, principally involved in the temporal transduction of photoperiodic information in all living organisms.
Biological signals 3(6):296-301.
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ABSTRACT: Aquatic ecosystems are exposed to an increasing contamination of pesticides such as herbicides through water runoff. The pulse-amplitude-modulation (PAM) fluorometric method, as a sensitive and rapid method, was used to evaluate toxic effect of these pollutants in Lemna minor. Four herbicides (paraquat, norflurazon, flazasulfuron and atrazine) often found in outdoor water samples and inducing specific changes in the yield of the in vivo chlorophyll a fluorescence of PSII were selected. These herbicides affected photosynthesis via different ways by: accepting electron from PSI, inhibiting carotenoids and protein biosynthesis or blocking PSII electron transport. Data revealed that photosynthetic parameters based on fluorescence emission were modified with the increase of herbicide concentration. The toxicity of these compounds was as follows (from greatest to least): paraquat>norflurazon>atrazine>flazasulfuron. Growth rate and photosynthetic pigments analysis confirmed the results obtained with PAM fluorometry. We found that among the fluorescence parameters the non-photochemical quenching was the most appropriate indicator for the effects of herbicides. The components of non-photochemical quenching were then resolved by examination of relaxation kinetics of quenching upon DCMU addition and light saturation pulse in the entire plant. Three kinetically distinct phases were observed which have previously been identified in thylakoids (Horton and Hague, 1988) as being due to energy-state quenching (qE), state transition (qT) and photoinhibition (qI). These examined NPQ components showed different levels of sensitivity to the effect of herbicide. It was found that: (i) qE was the major NPQ component; (ii) qE was affected by all the selected herbicides; (iii) qT was significantly modified by paraquat and atrazine; (iv) qI was affected by norflurazon and flazasulfuron. We interpreted these results by the pesticide mode-of-action. This study shows that the use of NPQ as a biomarker may be appropriate in laboratory and field herbicide bioassays. Moreover, application of non-photochemical quenching analysis may allow a better understanding of the mechanism of herbicide action.
Environmental and Experimental Botany.
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ABSTRACT: Toxicity of copper and folpet—two fungicides widely used on grape—was evaluated onLemna minorL., a sensitive aquatic weed regularly used for (eco)toxicological studies. Toxicity assessments were based on inhibition of growth and chlorophyll content ofL. minorcultures after 7 days. IC10, IC50, and IC90were determined for both compounds alone and were respectively, 0.03, 0.16, and 0.95 mg liter−1for copper and 1.20, 7.50, and >40 mg liter−1for folpet. When both compounds were combined, the response ofL. minordepended on the initial folpet concentration. Indeed, a slight synergy was observed for 5 mg liter−1folpet, while at folpet concentrations of 20 to 35 mg liter−1, the two fungicides were antagonists. The antagonism was positively correlated with folpet concentration. Antagonism between Cu and folpet could not be explained by a reduced bioavailability of Cu since concentration of free copper in the mixture did not depend on the presence of folpet. One physiological defense response elicited by copper in plants is an increase in catalase activity. Copper and folpet stimulated catalase activity and changes in the activity of the enzyme could not account for the synergy but possibly for the antagonism. Nevertheless, catalase activity increased significantly after a 24-h exposure to 25 μg liter−1of copper. The use of this property as a rapid and sensitive biomarker to monitor the toxicity of xenobiotics alone or in combination and of environmental water is discussed.
Ecotoxicology and Environmental Safety 40(3):194-200. · 2.29 Impact Factor
