RESUMO
Sea stars (Asterias rubens L.) were collected in different stations distributed in the Southern Bight of the North Sea. Concentrations of four heavy metals and six PCB congeners were measured in two body compartments (body wall and pyloric caeca). In order to assess the potential harm of these contaminants, two biochemical parameters were measured in sea stars, viz. reactive oxygen species (ROS) production by amoebocytes and cytochrome P450 immunopositive protein (CYP1A IPP) induction in pyloric caeca. Sea stars from stations located in the plume of the Scheldt river showed the highest contamination levels. Other stations, similarly located, displayed lower levels. No simple relationship could be established between ROS production by sea star amoebocytes and contaminant levels measured in sea star tissues. CYP1A IPP induction displayed more contrasted responses, and highly significant regressions were found between PCB concentrations measured in pyloric caeca and CYP1A IPP. Both biological parameters were found to vary significantly over the study area. On the whole, data indicated that contamination levels and subsequent effects in sea stars were comparable to those described in previous large-scale studies, but that working at a smaller scale highlighted the existence of patterns of contamination which can blur general trends due to major contamination sources like contaminated rivers.
Assuntos
Asterias , Metais Pesados , Bifenilos Policlorados , Poluentes Químicos da Água/análise , Animais , Asterias/efeitos dos fármacos , Asterias/crescimento & desenvolvimento , Asterias/metabolismo , Metais Pesados/análise , Metais Pesados/farmacocinética , Metais Pesados/toxicidade , Mar do Norte , Bifenilos Policlorados/análise , Bifenilos Policlorados/farmacocinética , Bifenilos Policlorados/toxicidade , Poluentes Químicos da Água/farmacocinética , Poluentes Químicos da Água/toxicidadeRESUMO
Levels of cytochrome P450 enzymes were measured in pyloric caeca microsomes of the asteroid Coscinasterias muricata following exposure to sediment with nominal concentrations of 0, 0.1 or 2 ml crude oil kg(-1) (dry weight) and subsequent depuration. No significant differences were observed in total cytochrome P450 levels or cytochrome P418 levels following the exposure period. However after five days of depuration, levels of total P450 in the pyloric caeca of C. muricata exposed to the highest oiled sediment concentration were significantly lower than in specimens exposed to the other treatments. Cytochrome P418 levels were inversely related to total P450 levels following exposure and subsequent depuration. Preliminary results show that levels of CYP1A-like immunopositive protein (CYP1A-like IPP) in exposed asteroids exhibited a concentration response relationship following the exposure period. Variations in CYP1A-like IPP levels observed during the depuration period may be influenced by the sublethal toxicity of hydrocarbons within the crude oil.
Assuntos
Sistema Enzimático do Citocromo P-450/efeitos dos fármacos , Petróleo/toxicidade , Estrelas-do-Mar/efeitos dos fármacos , Estrelas-do-Mar/enzimologia , Poluentes Químicos da Água/toxicidade , Animais , Austrália , Biomarcadores/análise , Sistema Enzimático do Citocromo P-450/metabolismo , Exposição Ambiental , Monitoramento Ambiental/métodos , Feminino , Sedimentos Geológicos , Masculino , Hidrocarbonetos Policíclicos Aromáticos/toxicidadeRESUMO
The importance of reactive oxygen species (ROS) production in invertebrate immunity prompted the use of this response in immunotoxicological studies in several taxa including marine organisms. In this chapter, we review the effects of environmental factors and contaminants such as heavy metals and polychlorinated biphenyls (PCBs) on the production of ROS by the main immune effector cells of echinoderms, the so-called amoebocytes. ROS production was measured by the peroxidase, luminol-enhanced chemiluminescence (PLCL) method. This method was found to predominantly reflect the production of superoxide anions and peroxides, among which hydrogen peroxide and peroxynitrite are the main species detected. Exogenous factors such as water temperature and salinity can influence this immune response in echinoderms. However, gender, handling stress and parasitism by a castrating ciliate apparently did not affect it. The impact of metals on ROS production differed greatly according to the duration and routes of exposure; in vitro and short-term in vivo exposures to metals caused an inhibition of this immune response, while the opposite effect was observed in a long-term in vivo exposure study. On the other hand, PCBs systematically had a stimulatory effect on ROS production independent of the echinoderm species or exposure routes. From the study of complex field contaminations, it appeared that contaminants released in the environment, such as metals, modulate starfish amoebocyte ROS production. This impact potentially represents a threat to the sustainability of natural populations of echinoderms and thereby to the stability of benthic ecosystems.
Assuntos
Alergia e Imunologia , Equinodermos/metabolismo , Luminescência , Luminol/farmacologia , Peroxidase/metabolismo , Espécies Reativas de Oxigênio , Animais , Bactérias/metabolismo , Ecossistema , Meio Ambiente , Feminino , Masculino , Temperatura , Fatores de Tempo , Toxicologia/instrumentação , Toxicologia/métodosRESUMO
Adult Paracentrotus lividus were exposed to a 14C-labelled PCB congener (PCB#153) using two different exposure modes: (1) the surrounding sea water and (2) the food (viz. the phanerogam Posidonia oceanica and the brown alga Taonia atomaria). Uptake kinetics from water and loss kinetics after single feeding were followed in four body compartments of the sea urchins (body wall, spines, gut and gonads). Results indicate that PCB bioaccumulation in P. lividus varies from one body compartment to another, with the exposure mode and the nature of the food. The echinoids accumulate PCB#153 more efficiently when exposed via water than via the food (the transfer efficiency is higher by one order of magnitude). Target body compartments of PCB#153 were found to be body wall and spines when individuals were exposed via water, and gut when they were exposed via food. It is concluded that P. lividus is an efficient bioaccumulator of PCB and that it could be considered as an interesting indicator for monitoring PCB contamination in the marine environment.
Assuntos
Bifenilos Policlorados/farmacologia , Ouriços-do-Mar/metabolismo , Poluentes Químicos da Água/farmacocinética , Ração Animal , Animais , Carga Corporal (Radioterapia) , Radioisótopos de Carbono/farmacocinética , Bifenilos Policlorados/toxicidade , Ouriços-do-Mar/química , Água do Mar , Testes de Toxicidade , Poluentes Químicos da Água/toxicidadeRESUMO
The cuttlefish Sepia officinalis was selected as a model cephalopod to study PCB bioaccumulation via seawater, sediments and food. Newly hatched, juvenile cuttlefish were exposed for 17 days to environmentally realistic concentrations of (14)C-labeled 2,2',4,4',5,5'-hexachlorobiphenyl (PCB#153) (18 ng PCB l(-1) seawater; 30 ng PCB g(-1) dry wt sediments; Artemia salina exposed to 18 ng PCB l(-1) seawater). Accumulation of PCB#153 was followed in three body compartments: digestive gland, cuttlebone and the combined remaining tissues. Results showed that (1) uptake kinetics were source- and body compartment-dependent, (2) for each body compartment, the accumulation was far greater when S. officinalis was exposed via seawater, (3) the cuttlebone accumulated little of the contaminant regardless of the source, and (4) the PCB congener showed a similar distribution pattern among the different body compartments following exposure to contaminated seawater, sediment or food with the lowest concentrations in the cuttlebone and the highest in the remaining tissues. The use of radiotracer techniques allowed delineating PCB kinetics in small whole organisms as well as in their separate tissues. The results underscore the enhanced ability of cephalopods to concentrate organic pollutants such as PCBs, and raise the question of potential risk to their predators in contaminated areas.
Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Moluscos/química , Bifenilos Policlorados/análise , Animais , Poluentes Ambientais/farmacocinética , Cadeia Alimentar , Sedimentos Geológicos , Moluscos/metabolismo , Bifenilos Policlorados/farmacocinética , Água do MarRESUMO
In invertebrates, the phagocytosis exerted by immune cells constitutes the main line of internal defence against offending microorganisms. This study assessed during two consecutive years the phagocytic activity in seastars (Asterias rubens) collected in stations along the Belgian and Dutch coasts. The contamination of these seastars by metals and PCBs were measured in parallel. Increased phagocytic activities were found in seastars collected in the plume of the Scheldt river. This correlated with the contamination of seastars by metals, mainly Pb, but not with the contamination by the analysed PCB congeners. Furthermore, the relationship between phagocytosis and metal contamination was reproducible from one year to another. The possible mechanisms explaining this effect are discussed in light of a direct or indirect link between phagocytic activity and metal contamination of seastars.
Assuntos
Monitoramento Ambiental/estatística & dados numéricos , Poluentes Ambientais/análise , Fagocitose/efeitos dos fármacos , Estrelas-do-Mar/química , Estrelas-do-Mar/imunologia , Análise de Variância , Animais , Poluentes Ambientais/toxicidade , Fluoresceína-5-Isotiocianato , Metais Pesados/análise , Metais Pesados/toxicidade , Mar do Norte , Bifenilos Policlorados/análise , Bifenilos Policlorados/toxicidade , Espectrofotometria , Estrelas-do-Mar/efeitos dos fármacosRESUMO
The activity of the enzyme 7-ethoxy-resorufin- O-deethylase (EROD) has been extensively used in biomonitoring studies for more than a decade. Although the analytical procedure is simple, it is often poorly characterized. In this study spectral properties of particular standard compounds used to measure EROD activity (ethoxyresorufin and resorufin, standards from Molecular Probes) were tested in order to optimize excitation and emission wavelengths to be used in the fluorimetric assay of EROD activity. The optimal excitation wavelength for the detection of resorufin was 560 nm. At this wavelength the excitation represents only 37% of its maximum level for ethoxyresorufin, while it represents 86% for resorufin. This allows discrimination between the fluorescence emitted by both standards, favoring the formed resorufin. Our results demonstrate that any analytical work using spectrofluorometry to measure EROD activity should be preceded by precise determination of the spectral characteristics of each set of standards used.
Assuntos
Citocromo P-450 CYP1A1/metabolismo , Monitoramento Ambiental/métodos , Espectrometria de Fluorescência/métodos , Oxazinas/isolamento & purificação , Análise EspectralRESUMO
The Southern Bight of the North Sea is particularly exposed to anthropogenic contamination, due to heavy urbanisation and industrialisation of its catchment area. The present work focuses on polychlorinated biphenyl (PCB) and metal contamination of the marine environment along and off the Belgian coast. Its objectives were to compare the concentrations of seven PCB congeners and four heavy metals in the sediments (a repository for anthropogenic contaminants) and in the asteroid Asterias rubens (a recognized bioindicator species). Nineteen sampling stations were considered between the mouth of the Scheldt Estuary and the southern limit of the Belgian coast (asteroids were found in 10 out of the 19 stations). PCB and metal concentrations measured in sediments and asteroids were in the range of values reported in previous studies. Stations under direct influence of the Scheldt were the most impacted by the considered contaminants. Metal concentrations varied according to the grain-size fraction considered. In asteroids, PCBs and metals were found to be selectively distributed among body compartments, and pyloric caeca were found to most efficiently discriminate between sampling stations contamination levels. PCB and metal analysis of sediments provided a physicochemical evaluation of the contamination, whereas analysis of asteroids introduced a biological dimension to the approach by taking into account bioavailability of the contaminants.
Assuntos
Poluentes Ambientais/análise , Sedimentos Geológicos/química , Metais Pesados/análise , Bifenilos Policlorados/análise , Estrelas-do-Mar/química , Animais , Monitoramento Ambiental , Poluentes Ambientais/farmacocinética , Metais Pesados/farmacocinética , Mar do Norte , Bifenilos Policlorados/farmacocinética , Distribuição TecidualRESUMO
The impact of four PCB congeners: 3,3',4,4'-tetrachlorobiphenyl (IUPAC congener #77), 3,3',4,4',5-pentachlorobiphenyl (IUPAC #126), 2,2',4,4',5,5'-hexachlorobiphenyl (IUPAC #153) and 3,3',4,4',5,5'-hexachlorobiphenyl (IUPAC #169) was investigated on the reactive oxygen species (ROS) production by coelomocytes of the echinoid Paracentrotus lividus, an important species in marine benthic ecosystems. PCBs were found to increase ROS production and to delay the time of peak production. These effects were stronger on bacteria-stimulated cells and were congener-specific: coplanar congeners (#77, 126 and 169) had more effect than the non-coplanar PCB #153. Among coplanar congeners, PCB #169 showed dose-dependent effects whereas PCB #77 and 126 were more toxic at high and low doses, respectively. The relative immunotoxicity of the different PCB congeners is discussed in the light of their structural properties and biological affinities.
Assuntos
Bifenilos Policlorados/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Ouriços-do-Mar/metabolismo , Animais , Relação Dose-Resposta a Droga , Exposição Ambiental , Medições Luminescentes , Bifenilos Policlorados/farmacocinética , Espécies Reativas de Oxigênio/imunologia , Ouriços-do-Mar/efeitos dos fármacos , Ouriços-do-Mar/imunologia , Testes de ToxicidadeRESUMO
Alzheimer's disease has long been associated with increased inflammation in the brain. Activated microglia and increased production of the inflammatory cytokines such as TNF-α, have been proposed to contribute to the onset and progression of the disease. We investigated if systemic administration of an anti-tumor necrosis factor (TNF) biologic medication clinically validated for rheumatoid arthritis (RA), TNF receptor 2 fused to a Fc domain (TNFR2:Fc), could ameliorate the behavioral symptoms and decrease neuroinflammation in a non-transgenic mouse model mimicking some hallmarks of the disease. Seven days after a single intracebroventricular (icv) injection of aggregated amyloid beta25-35 (9nmoles), mice displayed significant cognitive deficit in spontaneous alternation (working memory) and inhibitory avoidance (long-term memory) tasks. Alternation percentage decreased from 72.4%±1.3 to chance level (52.6%±1.7); step-through retention latency decreased from 247s to 144s. Subcutaneous administration of 30mg/kg TNFR2:Fc every second day post amyloid beta25-35 icv administration counteracted the amyloid-induced decrease in alternation percentage (66.4s±1.8) and the decreased step-through retention latency (248s±9). Measurement of hippocampal TNF-α levels by ELISA after behavioral assessment showed significant elevation in animals injected with amyloid beta25-35 relative to animals injected with control peptide. In animals treated with 30mg/kg TNFR2:Fc, TNF-α levels in the hippocampus were reduced and were similar to control animals. These data suggest that peripheral administration of TNFR2:Fc counteracts amyloid-induced memory impairment and normalizes increased TNF-α levels in hippocampus of a non-transgenic mouse model of amyloid induced cognitive deficit.
Assuntos
Amiloide/antagonistas & inibidores , Amiloide/toxicidade , Transtornos da Memória/metabolismo , Transtornos da Memória/prevenção & controle , Receptores do Fator de Necrose Tumoral/antagonistas & inibidores , Receptores do Fator de Necrose Tumoral/metabolismo , Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/toxicidade , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Transtornos da Memória/induzido quimicamente , Memória de Curto Prazo/efeitos dos fármacos , Camundongos , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/toxicidade , Desempenho Psicomotor/efeitos dos fármacos , Proteínas Recombinantes de Fusão/farmacologia , Fator 2 Associado a Receptor de TNF/genética , Fator 2 Associado a Receptor de TNF/farmacologiaRESUMO
There is considerable concern regarding dioxin-like compounds (DLCs) in the marine environment. These ubiquitous contaminants are highly resistant to degradation, highly accumulated by marine organisms, and extremely toxic. Concentrations of DLCs, including 7 polychlorodibenzo-p-dioxins, 10 polychlorodibenzofurans, and 4 coplanar polychlorinated biphenyls, were determined in sediments, mussels (Mytilus edulis), and sea stars (Asterias rubens) from five intertidal stations distributed along the Belgian coast and the English Channel. The induction of a biomarker, cytochrome P450 immunopositive protein (CYP1A IPP), was also measured in sea star pyloric caeca. Although no significant differences were found between the considered stations, DLC levels were found to be relatively high in biota, especially when the toxicity of these compounds is considered. Particular concern arises from TEQ values determined in mussels from all locations. Sea stars were found to be more discriminant between the stations. CYP1A IPP induction was found to be significantly related to DLC levels measured in sea stars and allowed significant discrimination between the considered stations.
Assuntos
Asterias/metabolismo , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Mytilus edulis/metabolismo , Poluentes Químicos da Água/análise , Animais , Bélgica , Benzofuranos/análise , Benzofuranos/farmacocinética , Dibenzofuranos Policlorados , França , Oceanos e Mares , Bifenilos Policlorados/análise , Bifenilos Policlorados/farmacocinética , Dibenzodioxinas Policloradas/análogos & derivados , Dibenzodioxinas Policloradas/análise , Dibenzodioxinas Policloradas/farmacocinética , Poluentes Químicos da Água/farmacocinéticaRESUMO
The study assessed the occurrence, possible toxicity, and impact of sediment-associated metals and PCBs in the coastal zone of the southern North Sea using echinoderms as representatives of the macrobenthos. Metals and PCBs were analyzed in the sediments and in the body compartments of the starfish Asterias rubens from 11 stations. The general toxicity of sediment-associated contaminants was assessed by bioassays using embryonic and larval developments of both A. rubens and the sea urchin Psammechinus miliaris. The impact of contamination was assessed by measuring cellular immune responses of A. rubens collected in the same stations. Contamination of the starfish by metals and PCBs closely reflected that of the sediments. However, bioaccumulation was element-specific for metals and depended on the chlorination pattern for PCBs. The sediment-associated contaminants appeared to be toxic in both the A. rubens and P. miliaris developmental assays. Moreover, metals were shown to affect the immune responses of starfishes living in contaminated stations. The most significant effects on biological responses were recorded in the plumes of the Scheldt/Rhine/North Sea Canal and the Elbe/Weser Rivers.