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Reproductive and developmental effects of endocrine disrupters in invertebrates: In vitro and in vivo approaches
Abstract
In order to gain basic understanding in the ecotoxicity of endocrine disrupting chemicals or EDCs (including natural chemicals and some pharmaceuticals), many international research groups are currently testing these chemicals using aquatic invertebrates. This paper discusses relevant examples to address key questions: which aquatic invertebrates are likely to be vulnerable to mammalian and non-mammalian EDCs; and which types of invertebrate chronic tests might be most sensitive and cost-effective to address potential environmental exposures? For a full review of invertebrate endocrine disrupter research see Endocrine Disruption in Invertebrates: Endocrinology, Testing and Assessment (1999). As an example, crustaceans are a particular focus of EDC research, reflecting their abundance in nature, commercial importance and their inclusion in the regulatory assessment schemes for active pharmaceutical ingredients (APIs). There is a diverse literature on the developmental and reproductive effects of mammalian EDCs in Crustacea, although there is growing evidence that such effects are probably not mediated via arthropod hormone systems. For example, recent studies in Europe using a marine copepod (Tisbe battagliai) life-cycle test have evaluated ecdysteroid agonists (e.g. 20-hydroxyecdysone), oestrogen agonists (e.g. diethylstilbestrol (DES), 17beta-oestradiol, oestrone and 17alpha-ethynylestradiol) and the pharmaceutical anti-oestrogen (ZM189, 154). While 20-hydroxyecdysone and DES were highly toxic, the other compounds tested show no significant toxicity to copepods. Furthermore, in vitro studies indicate that these environmental EDCs and several related APIs are not active against the ecdysteroid receptor. Therefore, other undefined modes of action appear to be responsible for crustacean toxicity in vivo and caution should be exercised before ascribing any apical effects to endogenous endocrine mechanisms, or before crustacean "EDC" data are extrapolated to other invertebrate taxa.
... In view of the observed interspecies differences in sensitivity to endocrine disrupting substances and the variety in endocrine systems and reproductive strategies, the feasibility of extrapolating between species has been questioned, especially for invertebrates (see e.g. Ingersoll et al. 1999, Hutchinson 2002, OECD 2006a). ...
... Within a single phylum, the pattern of species sensitivity may even vary for substances with a similar endocrine mechanism of action. As reviewed by Ingersoll et al. (1999) and Hutchinson (2002), different crustacean taxa differ in their sensitivity to endocrine disruption. Such differences were e.g. ...
... An environmental risk assessment procedure for potential endocrine disrupters should be based on tests with representatives from the most relevant taxonomic groups, including cnidarians, annelids, crustaceans, insects, molluscs and echinoderms (Hutchinson 2002, Matthiessen 2003, Oehlmann & Schulte-Oehlmann 2003, OECD 2006a. Ideally, representatives from all major taxa are needed (Oehlmann & Schulte-Oehlmann 2003) as long as the comparative sensitivity of different species / taxa to ECDs with different endocrine mechanisms of action has not been systematically evaluated as outlined above. ...
The aim of the present project was to identify the most relevant factors increasing the uncertainty of the environmental risk assessment (ERA) of endocrine active substances as compared to baseline toxicants. The evaluation was supported by data on endocrine effects of six model substances on fish and aquatic invertebrates. Two key factors were identified: (1) The current evaluation of endocrine effects only covers effects on the estrogen / androgen and thyroid axis, while other endocrine modes of action and, especially, effects on invertebrates are insufficiently covered. (2) At present, it is difficult to assess whether the results of tests with few standard test species are protective for all wildlife species. For fish, effect concentrations in species with similar metabolic capacities are often in the same order of magnitude, but larger differences are observed between species that differ in their metabolic capacities. For invertebrates, cross-species extrapolation is far more complex. This is due to the much higher diversity and heterogeneity of invertebrates and the often fragmentary knowledge on endocrine effects and the underlying processes. The uncertainty of the ERA of endocrine active substances is also increased by mixture effects. It may be increased if worst case exposure conditions coincide with sensitive developmental windows. Further factors (e.g. the irreversibility of effects, effects on the reproductive behaviour, and effects with uncertain population relevance and low-dose effects) and the specificity of the identified factors for endocrine active substances are discussed.
... Over the years, invertebrates have been found useful as model animals for investigating the toxicity of compounds in the environmental [13,43,51,21,35]. Macro invertebrates has been used regularly in the past for measuring the toxicity of chemicals because they are sensitive to toxic compounds and environmentally significant [26,37]. They are simple to handle, easy to rear, varieties of animal species to choose from and have short life span, hence, they are suitable for toxicity testing of water [35]. ...
Pharmaceuticals are continuously released into the aquatic environment mostly as wastewater effluents through sewage treatment plants, runoffs , effluents from pharmaceutical manufacturing companies etc. This results in chronic exposure of aquatic organisms to these substances and their metabolites. Although, the concentrations of pharmaceuticals in the aquatic environment are usually in ngL-1 to µg L-1 range, they are not likely to result in lethal toxicity. Nevertheless, extended and unabated exposure to low concentrations of drugs could lead to sublethal effects or even multigenerational effects. The aim of this study was to seek to improve the understanding of the effects of prolonged low-level exposure of Asellus aquaticus (aquatic macro-invertebrates) to mixtures of erythromycin, diclofenac and ibuprofen. On exposure to the mixture, growth rate decreased, feed intake was reduced but mortality was not significant for A. aquaticus. The effects of these pharmaceuticals on the growth, feeding and mortality of the test animal were as a result of the actions of the drugs and not attributed to a more general stress response. Although pharmaceuticals are indispensable to human health their usage and discharge to the aquatic environment coupled with their ecotoxicity to aquatic life may lead to ecological problems in the near future. Furthermore, this research confirms the suitability of the test species (A. aquaticus) as ecotoxicological test species that is both amenable to laboratory culture and sufficiently sensitive to provide reliable quantification of environmental risk.
... However, few works have been devoted to analyzing the adverse effects of EE2 on zooplankton species. For example, no significant chronic effects have been observed in the herpactocoid Nitocra spinipes after exposure to EE2 for 18 days [17]. In the water flea, Daphnia magna, toxicity effects were observed after exposure to EE2 [18]. ...
Estuaries are heavily impacted by pollutants from different sources such as urban sewage, industrial waste and agricultural runoff. Endocrine-disrupting chemicals (EDCs) are very concerning pollutants to estuarine wildlife, but little is known about their impact on microscopic biota such as zooplankton. The aim of this work was to investigate the effects of a model EDC, the 17α-ethi-nylestradiol (EE2), on two copepod species inhabiting the Basque coast (Southeastern Bay of Biscay) estuaries: Acartia clausi (autochthonous neritic species) and Acartia tonsa (non-indigenous brackish species). Female copepods were collected at population maximum time (spring for A. clausi and summer for A. tonsa) and exposed individually to 5 ng/L (low), 5 µg/L (medium) and 500 µg/L EE2 (high) doses, from environmental concentrations found in sewage effluents to toxicological concentrations. After 24 h exposure, the survival rate of experimental individuals was checked and the lethal concentration LC50 was calculated. The number of egg-producing females and the amount of egg laying and egg hatching were recorded. The integrated biomarker index (IBR) was calculated to integrate the overall effects of EE2 exposure. Both species had reduced survival rates at 500 µg/L, and the LC50 was lower in A. tonsa (158 µg/L) compared to A. clausi (398 µg/L). The number of eggs laid was significantly reduced in A. clausi at EE2 medium and high doses, while a reduction in the number of eggs in A. tonsa was observed only at the high dose. However, no significant differences were detected in the egg hatching success of exposed A. clausi and A. tonsa. IBR index showed that EE2 had the most detrimental effects on A. tonsa and A. clausi females at the 500 µg/L dose. In conclusion , after 24 h of exposure, EE2 reduced female copepod survival and disrupted reproductive output, but only at high non-environmentally relevant concentrations.
... Aquatic invertebrates have been widely used in ecotoxicological assays worldwide, mainly due to their importance in the food chain, diversity, geographic occurrence, and adaptability to laboratory conditions (Hutchinson 2002;Gorni & Alves 2012;Corbi et al. 2015;Rosner et al. 2021). Despite these organisms being abundant in the environment, few native worm species in tropical regions have been used as bioindicators of environmental contamination or ecotoxicological assessments (Chapman 2001;Gomes et al. 2017;Gazonato Neto et al. 2019). ...
Aquatic worms are considered a suitable group to evaluate the effects of contaminants on the environment, although one of the main challenges is to use the species of local occurrence. Recently, Pristina longiseta was suggested to be used in acute bioassays. In this context, this study aimed to establish a chronic exposure for ecotoxicological bioassays using the cosmopolitan species of occurrence in Brazilian freshwater P. longiseta. Firstly, we tested three exposure times (4, 7, and 10 days) under the presence or absence of aeration for reproduction outputs. After determining the best configuration (7 days without aeration), we assessed the effects of the chronic exposures using the standardized reference substance potassium chloride (KCl), the antibiotic sulfamethoxazole (SMX), the flame retardant tetrabromobisphenol A (TBBPA), and the sugarcane vinasse. Our results showed suitability for applying the chronic exposure using P. longiseta and indicated the sensitivity of the offspring to KCl (EC50-7d = 0.51 g/L). Sulfamethoxazole and TBBPA caused a significant decrease in the offspring of P. longiseta (EC50-7d = 59.9 µg/L and < 62.5 µg/L, respectively). Sugarcane vinasse showed high toxicity for the species, and 4.26% of vinasse was calculated as EC50-7d. Therefore, the described protocol was successfully applied as an ecotoxicological bioassay to evaluate the effects of environmental contaminants on the reproduction rate of the freshwater worm P. longiseta.
... Asterisks indicate statistically significant differences (*p < 0.05, **p < 0.01, and ***p < 0.001). endocrine disruption on ecdysteroidogenesis may cause abnormal development, leading to a chronic effect on D. magna (Hutchinson, 2002;Mu and LeBlanc, 2002). Correlated with previous research on EDCs (Haeba et al., 2008;Lambert et al., 2021), all our test groups exposed to PPP showed statistically significant differences in growth parameters. ...
Several phenol derivatives are suspected endocrine disruptors and have received attention in risk assessment studies for several decades owing to the structural similarity between estrogens and phenolic compounds. We assessed the endocrine disrupting effect of the phenolic compound para-phenylphenol (PPP) through acute tests and evaluating chronic endpoints in an invertebrate model, Daphnia magna. Exposure of D. magna to PPP induced substantial adverse effects, namely, reduced fecundity, slowed growth rate, delayed first brood, and a reduction in neonate size. Furthermore, we investigated the mRNA expression of relevant genes to elucidate the mechanism of endocrine disruption by PPP. Exposure of D. magna to PPP induced the substantial downregulation of genes and markers related to reproduction and development, such as EcR-A, EcR-B, Jhe, and Vtg. Consequently, we demonstrated that PPP has an endocrine disrupting effect on reproduction and development in D. magna.
... Aquatic invertebrates have been widely utilized in ecotoxicological assays around the world, mainly due to their importance in the food chain, diversity, geographic occurrence, and adaptability to laboratory conditions (Hutchinson, 2002 Pristina longiseta Ehrenberg, 1828 is a cosmopolitan freshwater species, and its occurrence was registered in Asia, Africa, Europe, and America (Brinkhurst and Jamieson, 1971;Harman, 1982 According to Van Cleave (1937) and Zattara et al. (2011), the reproduction of P. longiseta occurs mostly in an asexual way, by paratomic ssion, forming a new head and tail along the individual's body, and separating after their complete formation. The asexual reproduction ensures genetic stability and population abundance (Timm, 2012). ...
Aquatic worms are considered a suitable group to evaluate the effects of contaminants in the environment, although one of the main challenges is using native species. Recently, Pristina longiseta was suggested to be used in acute bioassays for tropical regions. In this context, the aim of this study was to establish a chronic exposure for ecotoxicological bioassays utilizing the tropical native species P. longiseta . Firstly, we tested three exposure times (96h, 7d, and 10d) in the presence and absence of aeration. After determining the best configuration, we evaluated the effects of the chronic exposures using the standardized reference substance potassium chloride, the antibiotic sulfamethoxazole, the flame retardant tetrabromobisphenol-A, and sugarcane vinasse. Our results showed the suitability for applying the chronic exposure using P. longiseta and indicated the sensitivity of the offspring to KCl (EC50 = 0.51 g/L). Sulfamethoxazole and TBBPA caused a significant reduction in the offspring of P. longiseta (EC50 = 59.9 µg/L and 166.1 µg/L, respectively). Sugarcane vinasse showed high toxicity for the species, and a fraction of 4.26% of vinasse was calculated as EC50. Therefore, the described protocol was successfully applied as an ecotoxicological assessment to evaluate the effects of contaminants on the reproduction rate of the freshwater worm P. longiseta .
... Over the years, invertebrates have been found useful as model animals for investigating the toxicity of compounds in the environmental [13,43,51,21,35]. Macro invertebrates has been used regularly in the past for measuring the toxicity of chemicals because they are sensitive to toxic compounds and environmentally significant [26,37]. They are simple to handle, easy to rear, varieties of animal species to choose from and have short life span, hence, they are suitable for toxicity testing of water [35]. ...
... One such group of PhACs are the synthetic oral contraceptives (basically applying estrogens and/or progestogens). For a long time, the estrogens were the most extensively studied contraceptive compounds; their effects have been shown on different invertebrate and vertebrate aquatic species (Bhandari et al. 2015;Caldwell et al. 2008;Costa et al. 2010;Huang et al. 2015;Hutchinson 2002;Islam et al. 2020;Kashian and Dodson 2004;Ketata et al. 2008;Matthiessen and Sumpter 1998;Torres et al. 2015;Zou and Fingerman 1997). Recently, another class of contraceptive pharmaceuticals has emerged into the focus in ecotoxicology: the progesterone (PRG) and its synthetic analogue progestins (e.g. ...
The presence of oral contraceptives (basically applying estrogens and/or progestogens) poses a challenge to animals living in aquatic ecosystems and reflects a rapidly growing concern worldwide. However, there is still a lack in knowledge about the behavioural effects induced by progestogens on the non-target species including molluscs. In the present study, environmental progestogen concentrations were summarised. Knowing this data, we exposed a well-established invertebrate model species, the great pond snail (Lymnaea stagnalis) to relevant equi-concentrations (1, 10, 100, and 500 ng L⁻¹) of mixtures of four progestogens (progesterone, drospirenone, gestodene, levonorgestrel) for 21 days. Significant alterations were observed in the embryonic development time, heart rate, feeding, and gliding activities of the embryos as well as in the feeding and locomotion activity of the adult specimens. All of the mixtures accelerated the embryonic development time and the gliding activity. Furthermore, the 10, 100, and 500 ng L⁻¹ mixtures increased the heart rate and feeding activity of the embryos. The 10, 100, and 500 ng L⁻¹ mixtures affected the feeding activity as well as the 1, 10, and 100 ng L⁻¹ mixtures influenced the locomotion of the adult specimens. The differences of these adult behaviours showed a biphasic response to the progestogen exposure; however, they changed approximately in the opposite way. In case of feeding activity, this dose-response phenomenon can be identified as a hormesis response. Based on the authors’ best knowledge, this is the first study to investigate the non-reproductive effects of progestogens occurring also in the environment on molluscan species. Our findings contribute to the global understanding of the effects of human progestogens, as these potential disruptors can influence the behavioural activities of non-target aquatic species. Future research should aim to understand the potential mechanisms (e.g., receptors, signal pathways) of progestogens induced behavioural alterations.
... Many reviews have reported about lists of suspected EDCs and proposed modes of action based on the examined studies (e.g. Hutchinson, 2002;Lagadic et al., 2007;LeBlanc, 2007;Oehlmann et al., 2007;Oetken et al., 2004;Rodríguez et al., 2007;Soin and Smagghe, 2007;Zou, 2005). ...
The crisis of biodiversity we currently experience raises the question of the impact of anthropogenic chemicals on wild life health. Endocrine disruptors are notably incriminated because of their possible effects on development and reproduction, including at very low doses. As commonly recorded in the field, the burden they impose on wild species also concerns invertebrates, with possible specificities linked with the specific physiology of these animals. A better understanding of chemically-mediated endocrine disruption in these species has clearly gained from knowledge accumulated on vertebrate models. But the molecular pathways specific to invertebrates also need to be reckoned, which implies dedicated research efforts to decipher their basic functioning in order to be able to assess its possible disruption. The recent rising of omics technologies opens the way to an intensification of these efforts on both aspects, even in species almost uninvestigated so far.
... tissue to a concentration as higher as 1000 folds than in water (Lepretti et al. 2015). Scientists have studied that NP could induce myriad physiological disruptions (Hutchinson 2002), inhibit development (Forget-Leray et al. 2005), influence the sexual organs and reduce population sizes (Baldwin et al. 2009) in aquatic invertebrates. However, little is known on the accumulation and depuration of NP in farmed aquatic animals. ...
Accumulation of nonylphenol (NP) in hepatopancreas, gonad, eyestalk, and muscle of freshwater prawn Macrobrachium rosenbergii following 72 h exposure to 100 µg/L NP, and depuration of NP in these tissues at 0.5–192 h post exposure were examined. We also examined the expressions of vitellogenin (Vg) and vitellogenin receptor (VgR) of prawn following 0–20 days exposure to 0, 1, 10, and 100 µg/L NP. NP accumulation in hepatopancreas and gonad with high concentration, and low concentration in muscle, but depurated faster in eyestalk and muscle. The expressions of vitellogenin (Vg) and vitellogenin receptor (VgR) increased directly with dose and time. In conclusion, NP accumulated significantly in gonad together with high Vg and VgR expressions, and depurated slow in hepatopancreas and gonad when prawns were removed back to control water. The induction of Vg and VgR under NP exposure might be a stress response in M. rosenbergii.
... In addition, molluscs, copepods and echinoderms proved to be particularly sensitive to bisphenol A and 4-tert-octylphenol, i.e. invertebrates possessing vertebrate-type hormones may exhibit a higher sensitivity to substances interacting with vertebrate-type endocrine processes than vertebrates. An environmental risk assessment procedure for potential endocrine disrupters should be based on tests with representatives from the most relevant taxonomic groups, including cnidarians, annelids, crustaceans, insects, molluscs and echinoderms (Hutchinson 2002, Matthiessen 2003, Oehlmann & Schulte-Oehlmann 2003, OECD 2006a Potamopyrgus anitpodarum is parthenogenetic, making it unsuitable for assesing effects on the male. Lymnaea stagnalis is hermaphroditic, making assessments on the male difficult, and the species appears less sensitive to potential effects than dioecious species, possibly as they can self fertilize. ...
... Many other toxicity evaluation methods have been developed, such as in vitro and in silico approaches, in addition to existing tools (Prot and Leclerc 2012). Other studies have proposed replacing vertebrate test animals with invertebrates, such as crustaceans and insects (Hutchinson 2002). Furthermore, the U.S. Environmental Protection Agency (EPA) created the ToxCast project, which integrates the results of in silico, in vitro, and in vivo tests to fill the data gap and compensate for the lack of reference animal test results (Martin et al. 2011). ...
Although medicines are less toxic than other toxicants, increased production and usage of pharmaceuticals have led to many concerns regarding their toxic effects on human and non-target organisms. Additionally, reproductive toxicity after long-term exposure is difficult to anticipate. Tamoxifen (TAM), a selective estrogen receptor modulator, has been widely used as an anticancer drug for mammalian breast and endometrial cancers. With increased TAM usage, it has frequently been reported that TAM is a potential endocrine disruptor capable of interfering with reproduction in non-target organisms. However, the mode of action of TAM in the endocrine system is unknown. In this study, we performed a 21-day chronic toxicity test using the crustacean Daphnia magna and investigated the transcriptional modulation of major genes related to the endocrine system, molting, development, and reproduction (i.e., Dm-vtg2, vmo1, cyp314, usp, and ecrb) after TAM exposure for 3, 6, 12, and 24 h. Our results showed a concentration-dependent decrease in the total number of offspring per individual, except for the concentration 25 μg/L; additionally, the expression of oogenesis-related genes was induced early but was later inhibited by TAM exposure. Additionally, molting-related genes were also downregulated in a time-dependent manner. Our findings suggested that TAM regulates reproduction by interfering with the molecular mechanisms involved in oogenesis and molting. This study supports the hypothesis that D. magna are a useful model to rapidly evaluate the reproductive effects of pharmaceuticals.
... Among Protostomes (i.e., Arthropods: insects and crustaceans) steroid molting hormones such as ecdysone have become important regulators of growth, development and reproduction [9]. Several studies have reported reproductive and developmental adverse effects after chronic exposure to EDCs acting as receptor agonist/antagonists of ecdysone and of juvenile hormones [10,11]. Data accumulated over the past two decades reveal substantial global contamination of EDCs by intentional or accidental release into the environment and incorporation into consumer products. ...
Wildlife has often presented and suggested the effects of endocrine disrupting chemicals (EDCs). Animal studies have given us an important opportunity to understand the mechanisms of action of many chemicals on the endocrine system and on neurodevelopment and behaviour, and to evaluate the effects of doses, time and duration of exposure. Although results are sometimes conflicting because of confounding factors, epidemiological studies in humans suggest effects of EDCs on prenatal growth, thyroid function, glucose metabolism and obesity, puberty, fertility, and on carcinogenesis mainly through epigenetic mechanisms. This manuscript reviews the reports of a multidisciplinary national meeting on this topic.
... Copper is a natural element which is widely distributed in soils, rocks and in rivers. It is released into water as a result of natural weathering of soil and discharges from industries and sewage treatment plants (Romo-Kroger et al., 1994 andHutchinson, 2002). The mean concentrations of Cu (mg L -1 ) in surface water from all sampling sites are shown in Table 3. ...
An assessment of heavy metal contamination (Cu, Zn, Pb, Cr, Mn and Cd) in surface water of Masinga reservoir was carried out between January 2013 and December 2013. The heavy metal Concentrations were determined using atomic absorption spectrophotometer (AAS). The data obtained was analyzed using one way analysis of variance and significant differences accepted at p ≤ 0.05. Post Hoc Tukeys' test was used to separate means. The mean metal concentrations (mg L-1) were; Cu (0.003-0.019), Zn (0.092-0.132), Pb (0.004-0.009), Cr (0.003-0.006) and Mn (0.006-0.146). No significant differences were observed in heavy metal concentrations in surface water among the different sites. The concentrations for all metals in surface water did not exceed the WHO recommended limit for drinking water.
... However, the tests registered are less complete than those performed on mammals. They are mainly focused on offspring production from exposed parents and concern only few species, such as fishes [2,7,8], birds [2,9], crustaceans [2,10] and earthworms [2,11] but not threatened pollinating insects, which are of great ecological and economical interest [12,13]. ...
Effets de stresseurs environnementaux sur la fertilite des males chez l'abeille domestique apis mellifera l. en relation avec la fécondite de la reine. Dans un contexte de déclin des colonies d’abeilles mellifères, un appauvrissement de la qualité des reines, se traduisant par une production anormale de couvain et des renouvellements prématurés de reines, a été rapporté par les apiculteurs du monde entier. Partant de ce constat, l’hypothèse avait été émise qu’une atteinte de la fertilité des mâles (faux-bourdons), exposés aux stresseurs environnementaux, pouvait être responsable des défaillances observées chez les reines au sein des ruchers. Dans le but de vérifier cette hypothèse, des approches novatrices pour élever des faux-bourdons, en conditions contrôlées de laboratoire et en conditions semi-contrôlées, ont été développées. Les approches mises en oeuvre ont permis de démontrer que l’insecticide systémique Fipronil, la microsporidie pathogène Nosema ceranae et leur association avaient la capacité de générer des perturbations physiologiques de différents types chez les faux-bourdons incluant des altérations de la qualité des semences. De plus, les effets obtenus après les expositions à ces stresseurs ont montré que la fonction de reproduction de ces individus était particulièrement sensible à l’ensemble des stresseurs étudiés. L’insémination instrumentale de jeunes reines, avec des semences de mâles exposés au Fipronil, a mis en lumière une baisse de leur potentiel reproducteur résultant d’une diminution non seulement du nombre mais aussi de la viabilité des spermatozoïdes stockés dans la spermathèque. Considérant que le contenu de la spermathèque conditionne leur capacité à pondre et leur longévité, ces reines sont donc plus disposées à présenter des signes de défaillance pouvant se répercuter sur le fonctionnement général de leur colonie. Ainsi, les troubles de la reproduction induits par une baisse de la fertilité des mâles, exposés à une multitude de stresseurs environnementaux, pourraient en partie expliquer le déclin des colonies d’abeilles. De ce fait, une évaluation des effets reprotoxiques des substances auxquelles les mâles sont potentiellement exposés, pourrait être envisagée dans un cadre règlementaire à venir. Ainsi, les méthodes et les approches innovantes développées dans le cadre de ce travail pourraient représenter des bases pertinentes pour élaborer de nouveaux tests toxicologiques qui pourraient être utilisés dans la procédure d’enregistrement des pesticides.
... As such, these disruptors have been shown to affect not only different reproductive stages but also different developmental stages of vertebrates (Guillette & Edwards, 2005;Segner et al., 2003). For example, it has been shown that ED can cause infertility due to malformations of the reproductive tract (Guillette, 2006), impaired release of pheromones (Anway & Skinner, 2008;Colborn, Vom Saal, & Soto, 1993;Guillette & Edwards, 2005;Segner et al., 2003), premature release of progesterone and progestin and occasional premature birth (Guillette, 2006;Longnecker, Klebanoff, Zhou, & Brock, 2001), changes in the development of oocytes, thyroid abnormalities and changes during molting (Depledge & Billinghurst, 1999;Ha & Choi, 2008;Hutchinson, 2002;Planelló, Martínez-Guitarte, & Morcillo, 2008;Rodríguez, Medesani, & Fingerman, 2007), and impaired immune functioning (Martineau et al., 1988). Experiments involving ED are complicated due to the fact that EDs often naturally come from multiple sources and can generate additive effects. ...
Water pollution due to human activities produces sedimentation, excessive nutrients, and toxic chemicals, and this, in turn, has an effect on the normal endocrine functioning of living beings. Overall, water pollution may affect some components of the fitness of organisms (e.g., developmental time and fertility). Some toxic compounds found in polluted waters are known as endocrine disruptors (ED), and among these are nonhalogenated phenolic chemicals such as bisphenol A and nonylphenol. To evaluate the effect of nonhalogenated phenolic chemicals on the endocrine system, we subjected two generations (F0 and F1) of Drosophila melanogaster to different concentrations of ED. Specifically, treatments involved wastewater, which had the highest level of ED (bisphenol A and nonylphenol) and treated wastewater from a constructed Heliconia psittacorum wetland with horizontal subsurface water flow (He); the treated wastewater was the treatment with the lowest level of ED. We evaluated the development time from egg to pupa and from pupa to adult as well as fertility. The results show that for individuals exposed to treated wastewater, the developmental time from egg to pupae was shorter in individuals of the F1 generation than in the F0 generation. Additionally, the time from pupae to adult was longer for flies growing in the H. psittacorum treated wastewater. Furthermore, fertility was lower in the F1 generation than in the F0 generation. Although different concentrations of bisphenol A and nonylphenol had no significant effect on the components of fitness of D. melanogaster (developmental time and fertility), there was a trend across generations, likely as a result of selection imposed on the flies. It is possible that the flies developed different strategies to avoid the effects of the various environmental stressors.
... Omurgalılarda üreme organlarının ve gametlerin gelişmesi gibi üreme modelleri, endokrin sistem içindeki biyokimyasal bir sinyal ağı tarafından koordine ve kontrol edilir. Knidli üremesini düzenleyen moleküler ve biyokimyasal sinyallerin mekanizması ise henüz tam olarak açıklığa kavuşmamıştır (Hutchinson, 2002). Knidliler çoğalmak ve nesillerini sürdürmek amacıyla eşeysiz olarak üreyebilen canlılardır. ...
... Recently, concerns about chronic toxicity have been expressed in the context of known and suspected effects of endocrine-disrupting compounds (EDCs) on aquatic organisms, wildlife and human health (Colborn et al., 1996;Cadbury, 1998;Kendall et al., 1998;Bechmann, 1999;Hutchinson, 2002;Hutchinson et al., 2006), as well as in the context of the ubiquitous halogenated hydrocarbons, such as certain pesticides (e.g. mirex, toxaphenes, malathion), DDT, PCBs, dioxins and furans, and some metals (e.g. ...
Contents:
A Short History of Aquatic Toxicology
The Aquatic Environment
Factors that Affect the Environmental Concentration of Chemicals
Basic Toxicological Concepts and Principles
Factors that Influence Toxicity
Toxic Agents and Their Effects
Examination of Concentration-Response Relationships
Toxicity Testing
Interpreting Toxicity Test Data
Biomonitoring
Toxicity Dada and Environmental Regulations
... This loss of energy reserves comprised a lower content of both glycogen and muscle protein (Frontera et al., 2011, for advanced juveniles), as well as a lower content of muscle lipids, and both muscle and hepatopancreatic proteins (Avigliano et al., 2014, for early juveniles). It is well known that energy reserves, whether carbohydrates, lipids or proteins are used to face the exposure to several stressors, both in fish and crustaceans (Hutchinson, 2002;Morris et al., 2005;Glusczak et al., 2006Glusczak et al., , 2007Frontera et al., 2011;Calvo et al., 2012Calvo et al., , 2013Avigliano et al., 2014;Stumpf et al., 2014). In juveniles of the studies species, a decreased growth rate, together with a utilization of energy reserves, has been reported under several unfavorable conditions acting as stressors (Jones, 1997;Calvo et al., 2013;Stumpf et al., 2014). ...
The effect of the herbicide atrazine was assayed in early juveniles of the redclaw crayfish Cherax quadricarinatus. Four cohorts of juveniles (a total of 280 animals) were exposed for 4 wk to each one of three atrazine concentrations (0.1, 0.5 and 2.5 mg/L) or a control (0 mg/L), from a commercial formulation having 90% of active principle. At the end of the exposure, no significant (p>0.05) differences in either mortality or molting were noted. However, the weight gain and the protein content of abdominal muscle decreased significantly (p<0.05) in the highest atrazine concentration as compared to control, indicating that atrazine acted as a relevant stressor, although at a concentration higher than those reported in the environment. Besides, the proportion of females increased progressively as the atrazine concentration increases, being significantly (p<0.05) higher than that of controls at the highest concentration assayed. Both macroscopic and histological analysis revealed a normal architecture of gonopores and gonads in both control and exposed animals. The obtained results strongly suggest that atrazine could be causing an endocrine disruption on the hormonal system responsible for the sexual differentiation of the studied species, increasing the proportion of female proportion without disturbing the gonad structure.
... EDCs can include metals, organic compounds, steroids and steroid-mimicking compounds, which may impact upon the survival, growth and/or reproduction of organisms (Luckenbach et al., 2010). However, the exact mechanisms of endocrine disruption in many invertebrates are yet to be established (Hutchinson, 2002). Levels of the sex steroid, 17b-oestradiol (E2), have been reported between ,0.5-4 ng g 21 in aquatic sediments (Liu et al., 2004). ...
Endocrine disruption has rarely been reported in field populations of the edible cockle and the context with the general health of the shellfish is unclear. This study examined the reproductive state of two Cerastoderma edule populations over a 6-month period to assess their reproductive condition, the incidence of intersex and presence of parasitic infection. A further seven native sites from south-west England were examined during the peak reproductive season to identify the presence of intersex within the region. Laboratory exposures of organisms collected from field populations showed a significantly female-biased sex ratio compared with controls when exposed to the endocrine disrupting chemicals, bisphenol-A (nominal concentration: 0.1 µg L−1) and 17β-oestradiol (nominal concentration: 0.1 µg L−1), but none of the chemical exposures induced intersex. Intersex was revealed in seven out of the nine native populations of C. edule sampled at peak reproductive season. The highest incidence and most severe case of intersex were reported at Lower Anderton on the River Tamer which also had a significantly female-biased sex ratio. Additionally, the dominant trematode family was the Bucephalaidae. Parasitic infection influences the maturity of C. edule by lowering both mean gonad index and condition index. These results suggest that endocrine disrupting chemicals could be contributing factors towards the development of intersex in C. edule.
... Although invertebrates account for roughly 95% of all animals, little research has been performed to understand effects of endocrine disruptors on these organisms, compared to the vertebrates. Hormones involved in growth, development and reproduction differ between vertebrates and invertebrates (Chang, 1997b;Charmantier et al., 1997;Huberman, 2000;Hutchinson, 2002;Subramoniam, 2000;USEPA, 2002;Verslycke et al., 2004a). There is a need to develop sensitive and relevant assays that evaluate endocrine toxicity in invertebrates, based on their unique signaling pathways. ...
... Although invertebrates account for roughly 95% of all animals, little research has been performed to understand effects of endocrine disruptors on these organisms, compared to the vertebrates. Hormones involved in growth, development and reproduction differ between vertebrates and invertebrates (Chang, 1997b;Charmantier et al., 1997;Huberman, 2000;Hutchinson, 2002;Subramoniam, 2000;USEPA, 2002;Verslycke et al., 2004a). There is a need to develop sensitive and relevant assays that evaluate endocrine toxicity in invertebrates, based on their unique signaling pathways. ...
... 以 表 征 该 化 学 物 质 的 细 胞 毒 性 ， 常 见 的 分 析 方 法 有 噻 唑 蓝 比 色 测 试 ［3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay］与细胞 死活荧光测试(ethidium bromide/calcein AM live/dead assay)。细胞毒性可在任何类 型的细胞中进行检测。相较而言，基因表达、酶产量(或酶活性)以及蛋白合成之类 的具体指标则往往依细胞种类而有所不同。例如，肝细胞系或其原代培养物常用于 检测化学物质对解毒酶的诱导表达。7-乙氧基异叻唑酮-脱乙基酶(ethoxyresorufin- O-deethylase ， EROD) 是 最 常 用 于 测 试 的 解 毒 酶 之 一 。 该 酶 是 细 胞 色 素 P450(cytochrome P450, CYP)酶系成员，由 CYP1A1 基因编码，并可被二 英 (dioxins)、多环芳烃(polyaromatic hydrocarbons，PAHs)、多氯联苯(polychlorinated biphenyls， PCBs)等污染物质所诱导 [4] 。 位于细胞表层或细胞内部的受体是化学物质对生物体产生效应的基本途径之 一。因此，环境污染物结合、激活或干扰细胞受体的能力备受关注。许多细胞系统 被 建 立 起 来 用 以 研 究 污 染 物 与 受 体 的 相 互 作 用 。 芳 香 烃 受 体 ( [18,19] 、卤虾(Artemia spp.) [20] 以及桡足类 [21] ；小型鱼类模型如日 鳉 本 鲭 鱼 (Oryzias latipes) 、 斑 马 鱼 (Danio rerio) [22] 和 黑 头 呆 鱼 (Pimephales promelas) [23] ；两栖类模型如非洲爪蛙(Xenopus laevis) [24] 。新的体内测试系统也被不 断开发出来以更好地体现自然界中生物多样性的广度 [25] 及解决特定的污染问题， 如内分泌干扰 [7,26] [39,40] 或效应导向分析(effect-directed analysis, EDA)(见 图 5) [ 因探针 [52] 。其他无须预先了解基因序列的方法，如基因表达系列分析(serial analysis of gene expression, SAGE) [52] 和差异显示技术(differential display) [ ...
... They affect the thyroid and adrenal gland functions and can act as estrogens, antiestrogens and antiandrogens [1]. Exposure to EDCs has been associated with several diseases involving the reproductive [2][3][4][5], immune [6,7] and neurological [8,9] systems and has also been associated with developmental dysfunc- tions [10,11]. EDCs have been found in almost all water matrices including treated and untreated wastewaters, surface waters, groundwaters, and even drinking waters [12][13][14][15]. ...
With the recent wide spread concerns of the environmental and public health effects of endocrine disrupting chemicals (EDCs), it is becoming important to develop new techniques to remove these substances from wastewater. EDCs find their way to the environment mainly via effluents from WWTPs. They are often cited as moderately hydrophobic, hence they have tendency to distribute to organic solvents and can then be removed using liquid-liquid extraction (LLE) techniques. However, despite being a mature chemical engineering unit operation, LLE has not been studied for the removal of EDCs in water. This study investigated the removal of three EDCs of concerns including estrone (E1), 17 beta-estradiol (E2), and 17 alpha-ethinylestradiol (EE2) using decamethylcyclopentasiloxane (D5) as an extraction solvent in three water matrix types (Milli-Q, tap water, and a secondary treated wastewater). The study showed that all three EDCs were distributed to D5 but at varying distribution coefficients: K-E1 = 2.66, K-E2 = 0.61 and K-EE2 = 1.67 +/- 5% at pH 6 and 20 degrees C. Due to the high pK(a) values of the three EDCs, pH had no significant effect on K-EDCs up to about pH 9.5 but higher pHs reduced the distribution ratios up to almost zero at pH 12. Van't Hoff equation described the effect of temperature on K-EDCs and showed that the process was endothermic. The overall estrogenic potency of the three EDCs in mixtures was quantified with an E2 equivalent potency, which was found to distribute well into the solvent at a K-E2EQ= 1.43. The study suggests that LLE is an effective method to remove estrogenic potency of wastewater.
... Potential adverse developmental and reproductive effects of BPA in invertebrates needs clarification, particularly since invertebrates represent 95% of all animal species. In addition, the aquatic organisms may not be ideal reprentatives of the major invertebrate groups [1,14]. From this point of view Drosophila melanogaster can be a suitable organism to determine adverse effects of these chemicals because of its short developmental cycle. ...
The aim of this study was to investigate the effects of BPA that is one of the endocrine disrupting chemicals (EDCs) on the development and reproduction of Drosophila melanogaster. Larvae of D. melanogaster were exposed to 0.1 mg/L, 1 mg/L and 10mg/L BPA. The percentages and times of transition from larvae to pupae and from pupae to adults and the mean offspring number were determined. No differences were found in the transition percentages from larvae to pupae and from pupae to adults (p > 0.05). However, it was found that both the mean pupation and the mean maturation times were delayed with BPA exposures (p < 0.05). In the 0.1 mg/L and 1 mg/L exposed groups, the mean offspring numbers were significantly less than that of the control groups (p < 0.05).
... En este sentido, los copépodos, a diferencia de los cladóceros, presentan un ciclo de vida altamente complejo, pero a la vez muy favorable para la obtención de información sobre los efectos tóxicos en cada etapa (Kovatch et al, 1999). Esta característica permite además obtener una mayor aproximación sobre las respuestas poblacionales (Hutchinson 2002). El desarrollo de los copépodos incluye el paso por doce estadios larvarios y una metamorfosis de la morfología naupliar (N6) a la de copepodito (C1). ...
El incremento de los metales en los cuerpos de agua dulce a causa de las actividades antropogénicas genera importantes alteraciones sobre la biota. Esta revisión analiza los efectos adversos de varios metales de relevancia ecotoxicológica sobre los microcrustáceos zooplanctónicos (cladóceros y copépodos), los avances experimentales en esta línea y las ventajas de cada grupo como organismos test. En general, la necesidad de obtener indicadores más sensibles y representativos que los tradicionales, promovió lineamientos hacia estudios subcrónicos, interspecíficos y multigeneracionales. Por otra parte, la tendencia actual hacia el estudio de mezclas de sustancias y los efectos indirectos permite adquirir una visión más integral del problema. El impacto sobre las poblaciones es muy variable, dependiendo de la naturaleza del metal, las características del medio, el tiempo de exposición, las condiciones de cultivo y aspectos genéticos. Sin embargo, la mayoría de los trabajos se centran en pocas especies, dejando vacancias en el conocimiento de las representantes de cada región particular. Si bien algunos atributos de los cladóceros y copépodos como el tamaño, la morfología y el rol ecológico los tornan buenos indicadores, las diferencias en el desarrollo, reproducción y estrategias de perpetuación confieren ventajas a un grupo sobre otro.
... Four of these 12 addressed the effect of endocrine-disrupting chemicals (EDCs). Endocrine-disrupting chemicals are ubiquitous in the environment, and their effects on animal behavior have received increasing attention (Fingerman et al. 1998, 416 synthesis Depledge and Billinghurst 1999, Hutchinson 2002, Clotfelter et al. 2004, Verslycke et al. 2004, Zala and Penn 2004. Endocrine-disrupting chemicals may act both as agonists (i.e., any molecule that improves the activity of a different molecule, e.g., a hormone) and antagonists (i.e., any molecule that blocks the ability of a given chemical to bind to its receptor, preventing a biological response), inducing either underproduction or overproduction of hormones (Clotfelter et al. 2004, Zala andPenn 2004). ...
... Modern molecular and comparative toxicology studies are rapidly helping to better define these similarities and differences so that there is a stronger scientific rationale to help select which aquatic species are best used for environmental assessments. Both in vitro and in vivo data can be helpful in this context (9). Interestingly, biomedical scientists see a reciprocal value in using aquatic organisms to help guide drug discovery (10). ...
Current approaches to generating and interpreting ecotoxicological effects data in aquatic organisms were discussed in a workshop. Scientific principles underpinning historical “base set” acute testing (typically using freshwater algae, daphnids, fish) and the more recent requirement to adopt chronic sublethal test guidelines were discussed. Participants discussed ideas to develop improved testing methods for chronic pharmacological and toxic effects based on the premise that useful ecotoxicity information can be leveraged from both in vitro and in vivo preclinical studies. For example, one approach is to consider a primary pharmacological mechanism in mammals (the mammalian-fish leverage model) and to use these mechanistic biomarker data as “signposts” to guide the efficient assessment of sublethal chronic testing in aquatic life. The usefulness of data obtained in test systems on the molecular, cellular, organ-organismal, and population levels of biological organization for environmental risk assessment was evaluated and integrated with animal (vertebrate) welfare considerations.
La necesidad de obtener herramientas metodológicas adecuadas y representativas que permitan medir el impacto de los xenobióticos y el efecto de ciertos estresantes naturales, como son los comunicadores químicos (infoquímicos) indicadores de depredación sobre los integrantes del zooplancton, promovió el desarrollo de la presente tesis.
Dado que el comportamiento representa una respuesta integrada y de relevancia ecológica para los organismos frente a diversas situaciones ambientales, se ha considerado un parámetro de potencial significancia, tanto para estudios ecológicos como ecotoxicológicos. Este parámetro permitiría reconocer respuestas rápidas y no destructivas a diversos estresantes y estimar posibles consecuencias poblacionales a largo plazo.
Partiendo de estas premisas, se propuso la hipótesis de que los contaminantes y los infoquímicos indicadores de depredación son capaces de modificar el comportamiento de los microcrustáceos del zooplancton, y que dichas modificaciones constituyen biomarcadores sensibles y tempranos.
Para ello se realizaron numerosos trabajos experimentales bajo condiciones controladas de laboratorio utilizando tres especies de cladóceros (Daphnia magna, Ceriodaphnia dubia, Pseudosida variabilis) y dos de copépodos (Argyrodiaptomus falcifer y Notodiaptomus conifer). Los experimentos se realizaron en tres etapas que comprendieron ensayos de toxicidad aguda, de ciclo de vida y de comportamiento. Para estos últimos se diseñaron dispositivos específicos que permitieron evaluar la migración vertical diaria (MVD) y la capacidad de escape de los organismos mencionados. En ambos casos se realizaron numerosos experimentos previos que permitieron definir los patrones “normales” de comportamiento. Posteriormente se analizaron las respectivas respuestas ante la presencia de diferentes concentraciones de metales (cromo y cobre), un insecticida comercial (cuyo componente activo es el endosulfán) e infoquímicos de un pez zooplanctófago, Cnesterodon decemmaculatus.
Los resultados demostraron que los organismos estudiados son sensibles a los infoquímicos. Esto se observó en la gran plasticidad fenotípica registrada en el ciclo de vida del copépodo N. conifer y en las modificaciones etológicas de las cinco especies, luego de la exposición al medio con dichos comunicadores.
Considerando los efectos de los xenobióticos, en general los parámetros reproductivos constituyeron los indicadores de efecto más sensibles en los estudios de ciclo de vida. Sin embargo, las alteraciones en la habilidad de escape y los movimientos migratorios resultaron ser mejores biomarcadores de los contaminantes utilizados, permitiendo detectar el impacto a concentraciones menores que las que generaron respuestas negativas tanto en los ensayos agudos como en los crónicos.
Dada la importancia del comportamiento en la distribución y éxito evolutivo de los organismos en la naturaleza, las posibles alteraciones en dicho parámetro podrían generar serias consecuencias negativas, no sólo para el zooplancton sino también para los eslabones tróficos vinculados a ellos.
Finalmente, la elevada sensibilidad de N. conifer y P. variabilis (al compararlas con otros microcrustáceos utilizados en estudios ecotoxicológicos) y su gran representatividad de los ambientes neotropicales, permiten sugerirlas como especies muy adecuadas para futuros trabajos en esta línea de investigación.
Invertebrates are recognized as important species in endocrine disrupting chemical (EDC) testing. However, it is poorly understood whether the effects of EDCs in invertebrates are mediated by hormonal mechanisms. Previously, we showed that bisphenol A (BPA) affected the physiology of the freshwater oligochaete Lumbriculus variegatus. In the present study, we examined the mechanism of the impact of BPA on L. variegatus, using pulse rate of the dorsal blood vessel (DBV) as an endpoint. Both long term and acute exposures to BPA increased the pulsing rate of DBV. The former had a distinct inverted-U dose response relationship with a most efficacious dose of 10⁻⁹ M, which increased the pulse rate from 8.97 to 10.9 beats/min. The effects of BPA were mimicked by the synthetic estrogen ethinylestradiol with a most efficacious dose of 10⁻¹² M. Interestingly E2 had no effect on pulsing rate, either acute or long term. The sensitivity of L. variegatus to estrogens were exquisite, with detectable effects at 10⁻¹⁴ to 10⁻¹⁰ M range. Both the long term and acute effects of BPA were partially or fully blocked by various vertebrate estrogen receptor (ER) antagonists, including ICI 182,780, MPP and G15. Our results suggest that the impact of BPA on pulsing rate of L. variegatus is likely mediated by an estrogenic mechanism instead of general toxicity. The exceptionally high sensitivity of L. variegatus to some estrogens makes it a possible tool for estrogenic EDC screening.
Toxicological Effects of Veterinary Medicinal Products in Humans is the first definitive guide to discuss the adverse effects of veterinary medicinal products in humans. The chapters focus on occupational safety and consumer issues and examine the circumstances under which exposure is likely to occur. To be in context, it reviews this against the background of adverse health effects from other sources in the veterinary and farming professions. The book examines adverse drug effects reported to regulatory agencies (mainly the FDAÆs Center for Veterinary Medicine) and then considers a series of individual drugs, including antibiotics, anaesthetics and organophosphorus compounds. The chapters also discuss the fundamental aspects of regulatory issues relating to safety assessment, and examine the manner in which user safety is assessed prior to authorisation/approval and what measures can be taken after authorisation/approval in the light of findings from pharmacovigilance activities. There is growing concern over the issue of antimicrobial resistance and the contribution made by veterinary medicinal products. This too is addressed along with the significance to human health and measures that can be taken to mitigate the effects (if any) of the use of antibiotics in animals e.g. prudent use measures. The book will be an essential resource for medical practitioners in hospitals and general practice, pharmaceutical industry scientists, analysts, regulators and risk managers.
Bisphenol A (BPA) is an environmental estrogen that occurs widely in the aquatic environment and causes feminization to various species, including fishes and gastropods. This study aims to develop the water quality criteria for BPA in the marine environment using the species sensitivity distribution (SSD) methodology from a scientific basis. Both acute and chronic toxicity data tested with saltwater species resident to China were collected. Additional tests were conducted to supplement toxicity data with local saltwater biota, including mollusk (Ruditapes philippinarum) and fish species (Scophthalmus maximus and Pagrosomus major). Based on SSD modelling, the criterion maximum concentration of BPA was estimated to be 273 μg/L. The criterion continuous concentration (CCC) for reproductive and non-reproductive effects was calculated to be 0.46 μg/L and 4.90 μg/L, respectively. Based on the derived criteria, the acute risk of BPA in coastal waters of China was determined to be negligible with RQs (risk quotients) of <0.01. The chronic risk was however much higher with RQs of up to 0.4 and 4.3 based on non-reproductive and reproductive CCC, respectively. The ecological risk assessment for BPA based on reproductive CCC can, therefore, better protect the safety of marine species.
The honey bee is threatened by biological agents and pesticides that can act in combination to
induce synergistic effects on its physiology and lifespan. The synergistic effects of a parasite/pesticide
combination have been demonstrated on workers and queens, but no studies have been performed
on drones despite their essential contribution to colony sustainability by providing semen diversity
and quality. The effects of the Nosema ceranae/fipronil combination on the life traits and physiology of
mature drones were examined following exposure under semi-field conditions. The results showed that
the microsporidia alone induced moderate and localized effects in the midgut, whereas fipronil alone
induced moderate and generalized effects. The parasite/insecticide combination drastically affected
both physiology and survival, exhibiting an important and significant generalized action that could
jeopardize mating success. In terms of fertility, semen was strongly impacted regardless of stressor,
suggesting that drone reproductive functions are very sensitive to stress factors. These findings suggest
that drone health and fertility impairment might contribute to poorly mated queens, leading to the
storage of poor quality semen and poor spermathecae diversity. Thus, the queens failures observed in
recent years might result from the continuous exposure of drones to multiple environmental stressors.
The xenoestrogen 4-nonylphenol (NP) is a ubiquitous aquatic pollutant and has been shown to impair reproduction, development, growth and, more recently, immune function in marine invertebrates. We investigated the effects of short-term (7 d) exposure to low (2 μg l⁻¹) and high (100 μg l⁻¹) levels of NP on cellular and humoral elements of the innate immune response of Crassostrea gigas to a bacterial challenge. To this end, we measured 1) total hemocyte counts (THC), 2) relative transcript abundance of ten immune-related genes (defh1, defh2, bigdef1, bigdef2, bpi, lysozyme-1, galectin, C-type lectin 2, timp, and transglutaminase) in the hemocytes, gill and mantle, and 3) hemolymph plasma lysozyme activity, following experimental Vibrio campbellii infection. Both low and high levels of NP were found to repress a bacteria-induced increase in THC observed in the control oysters. While several genes were differentially expressed following bacterial introduction (bigdef2, bpi, lysozyme-1, timp, transglutaminase), only two genes (bpi in the hemocytes, transglutaminase in the mantle) exhibited a different bacteria-induced expression profile following NP exposure, relative to the control oysters. Independently of infection-status, exposure to NP also altered mRNA transcript abundance of several genes (bpi, galectin, C-type lectin 2) in naïve, saline-injected oysters. Finally, plasma lysozyme activity levels were significantly higher in low dose NP-treated oysters (both naïve and bacteria challenged) relative to control oysters. Combined, these results suggest that exposure to ecologically-relevant (low) and extreme (high) levels of NP can alter both cellular and humoral elements of the innate immune response in C. gigas, an aquaculture species of global economic importance.
The individual and combined toxicities of acetaminophen, carbamazepine, diclofenac and ibuprofen have been examined in neonate nauplii (<24 h-old) of the harpacticoid copepod Tisbe battagliai. Based on acute toxicity data (LC50) obtained, diclofenac was the most toxic compound with an LC50 value of 9.5 mg·L(-1); this is between 5 and 7 times lower than the LC50 value for acetaminophen, carbamazepine and ibuprofen (67.8 mg·L(-1), 59 mg·L(-1) and 49.7 mg·L(-1) respectively). The environmental risk posed by the selected pharmaceuticals was assessed by calculating risk quotients (RQs) based on MEC (the highest exposure concentration of the compound in the medium)/PNEC (predicted no effect concentration) ratios. Results suggest that, at environmental concentrations, none of the compounds is harmful for the aquatic environment (low or no risk). Toxicity data obtained for mixtures were compared with predictions derived from three different models: Concentration Addition (CA), Independent Action (IA) and Combination Index (CI). The classical modeling approaches CA and IA failed to predict the observed mixture toxicity, thus indicating that single compound toxicity data are not sufficient to predict toxicity of drug mixtures on Tisbe species. However, the use of the CI seems to provide better predictions of pharmaceutical toxicity.
The aim of the present study was to investigate the lethal and sublethal effects of prednisolone (PDS) exposure on the embryonic and post-hatching stage of the freshwater snail, Physa acuta. The egg masses were exposed for 14 d to PDS concentrations ranging from 15.6 to 1000 µg/L. PDS treatments from 125 to 1000 µg/L resulted in significant decline in growth, survival, heart rate and notable abnormalities in embryonic development. Premature embryonic hatching was observed in lower concentrations of 31.25 and 62.5 µg/L, whereas delayed hatching was seen in concentrations from 125 to 1000 µg/L. To assess impacts of PDS exposure on the hatched juveniles, the drug exposure was extended for another 28 d. Impairment in shell development was noted in juveniles exposed to concentrations from 62.5 to 1000 µg/L at the end of 42 d, which resulted in thin and fragile shells. The thickness of shells in snails exposed to 1000 µg/L was significantly lower in comparison to those in the 15.6 µg/L and control treatments. In addition, lower calcium concentration in shells of the exposed juvenile snails in treatments 62.5-1000 µg/L consequently reduced their growth. The present study confirms that a continuous exposure to PDS can result in deleterious effects on the calcium deposition resulting in shell thinning in the freshwater snail, P. acuta. This article is protected by copyright. All rights reserved.
Bamba Bukengu Muhaya1, Amakay Bukas1, François Toto Lubala2, Pierre Kambuli Kaseti2 and Joel Bacirheba
Mugisho2
1. Department of Chemistry, Faculty of Science, Lubumbashi University, Lubumbashi 1825, D.R. Congo
2. Department of Geology, Faculty of Science, Lubumbashi University, Lubumbashi 1825, D.R. Congo
Abstract: Concentrations of Co, Cu, Cr, Fe, Pb and Zn were investigated in samples of five types of soils: Dembo soil SDC, red clay
soil SAR, red clay soil with black spots SAK, lateritic soil SLS and garbage dump soil SNB from the North-eastern Lubumbashi city
in the Democratic Republic of Congo from February to July 2011, corresponding to three months (February-April) of rainy season
and three months (May-July) of dry season. Of the five soil types, SDC and SNB had higher Co, Cr, Fe and Pb concentrations at A
and B horizons than the other soils. In those two soil types, respective mean concentrations of Co were 143 mg/kg and 485 mg/kg;
those of Cr were 105 mg/kg and 124 mg/kg, those of Fe were 42,420 mg/kg and 41,327 mg/kg, and those of Pb were 21 mg/kg and
1,837 mg/kg. Both SDC and SNB soils had also high organic matter content varying from 4.04% to 13.36% and from 5.8% to 11.9%,
respectively. Their pH values ranged from 6.9 to 7.8 and from 7.3 to 8.0, respectively.
Bioassays are used in environmental toxicology to examine the effects of man-made contaminants on individual organisms and ecosystems. These tests involve examining the effects of individual chemicals or complex mixtures, such as effluents, on representative biological systems or whole organisms, and are commonly incorporated into environmental monitoring programs. Bioassays can be conducted either in vitro by the use of cell culture techniques in the laboratory or in vivo in either the laboratory or the field. In vitro bioassays are frequently used to assess specific mechanisms of action of the contaminants that are present in an environmental sample, such as receptor-binding properties, whereas in vivo bioassays provide a more integrated organism response. However,there are many endpoints that can be measured using both types of approaches, such as effects on growth, endocrine function, and DNA damage. Both in vivo and in vitro bioassay approaches offer their own advantages and disadvantages, some of which can be addressed using the toxicity identification and evaluation procedure. Future development of a wider range of bioassays that more fully reflect the diversity of organisms in natural systems will contribute to more accurate understanding of the potential effects of environmental contaminants.
Many sources exist that contain valuable information on toxicology testing methods comprising in vivo (use of whole animals) and in vitro (use of artificial environment outside of living organisms) testing methods. The information resources presented in this chapter relate to chemical substances and are collected to provide key guidance on available information on in vivo, in vitro, and other toxicological testing and assessment methods (e.g., in silico toxicological methods performed on computer or via computer simulation), on relevant databases, published literature, books and journals, teaching aids, and finally organizations, foundations, and testing laboratories involved in toxicity assessment. The current information is of relevance for research, applied sciences and policy implementation purposes, such as the implementation of the European Union's (EU's) chemicals policy REACH (Registration, Evaluation, Authorisation, and Restriction of CHemicals) or the GPSD (General Product Safety Directive). The provided information resources are recommended starting points when searching for information on testing methods, alternative testing methods and computational assessment methods.
Four categories of anthropogenic stressors affect the behavior and vital functions of crustaceans in aquatic ecosystems: pollution, introduction of non-indigenous species, stock manipulation, and habitat destruction. The most affected vital functions are, in descending order of importance, reproduction, nutrition and growth, and habitat selection. Two principal groups of stressors were distinguished: (i) pollution and species introduction, for which most of the effects on crustacean behavior were observed directly; and (ii) fishing and habitat destruction, for which most of the evidence was circumstantial. In many cases, pollution and species introduction affect individuals directly, whereas fishing and habitat destruction affect crustacean behaviors indirectly, primarily by changes in important population (e.g., sex ratio and population density) or ecosystem (e.g., habitat, physicochemical, species dominance, species composition) parameters. The information yielded by this review and that of future studies may prove useful in designing efficient conservation plans.
Swimming behavior is increasingly reported as a sensitive and early indicator of toxicant stress in aquatic organisms. However, it remains unclear how to quantify the sensitivity of swimming behavioral endpoints and how to compare these effect thresholds with standard ecotoxicological endpoints used in risk assessment. To date, the systematic assessment of the sensitivity of swimming behavioral endpoints in daphnia is limited because of the restrained test capacity of existing behavioral analysis systems. Hence, we developed a new behavioral analysis multi-cellsystemnamed “Multi-DaphTrack” with a high throughput testing capacity in order to enhance our understanding of swimming behavioral effects in Daphnia magnaunder chemical exposure. Twelve compounds covering different modes oftoxic action were selected and tested in this new system andin a single-cell commercialized biomonitor (DaphToxI®) and with the acute standard test.Our new multi-cellexposure system detectedsignificant and early swimming behavioral effects (i.e.,increase of the average speed) for most of the tested compounds and this, from the first hour of exposure at concentrations near the EC10(48h). Contrastedbehavioral profiles were observed for average speed (i.e., intensity, time of effect onset, effect duration), but no distinct behavioral profiles could be drawn from the chemical mode of action. Despite less sensitive,the DaphToxI®gave similar trends (i.e.,rapid peak increase) compared to our “Multi-DaphTrack” system. To conclude, behavior analysis using our “Multi-DaphTrack”systemcould be used as an alternative or complement to the current acute standard test for toxicity assessment of chemicals. With some additional improvements and validations, it also could be used forquality assessment of waterbodiesand sewages.
This chapter presents an overview of crustacean endocrinology. It highlights potential endocrine-mediated effects observed in crustaceans over the last decade, including end points that are reflective of endocrine disruption in crustaceans. The subchronic/chronic standard test protocols that are available for assessment of chemical substances within the major standardization bodies are summarized, as are some complementary genomic tools, which may be used for improved understanding of endocrine disruption in crustaceans. Finally, the chapter summarizes the main findings and presents some final recommendations.
Variations in the level of stress proteins (hsp70 and hsp90) were measured during the reproductive cycle of the amphipod crustacean, Gammarus fossarum (Koch 1835). The reproductive cycle was determined histologically while the heat shock protein-levels were measured by an immunoblotting assay. Gammarids of defined body length were kept in a glass aquarium for 12 weeks under constant conditions. Animals were removed every 14 days for investigation. Histological investigations showed that the maturation stage of the female gonad could be identified according to the structure of the oocytes, and that an almost complete reproductive cycle occurred within 12 weeks. Hsp70 and hsp90 levels were found to be inversely correlated over the course of the reproductive cycle. At the beginning of the reproductive cycle, the hsp90 level was found to be low while that of hsp70 was at its peak, whereas, at the end of the cycle, when mature oocytes are present, the opposite was true. The data indicate that the levels of stress proteins reflect the maturity stage of the oocytes. This finding provides prerequisite baseline information to interpret biomarker studies on endocrine effects of chemicals in gammarids.
Daphnia magna is a bio-indicator organism accepted by several international water qual- ity regulatory agencies. Current approaches for assessment of water quality rely on acute and chronic toxicity that provide no insight into the cause of toxicity. Recently, molecular ap- proaches, such as genome wide gene expression responses, are enabling an alternative mecha- nism based approach to toxicity assessment. While these genomic methods are providing im- portant mechanistic insight into toxicity, statistically robust prediction systems that allow the identification of chemical contaminants from the molecular response to exposure are needed. Here we apply advanced machine learning approaches to develop predictive models of con- taminant exposure using a D. magna gene expression dataset for 36 chemical exposures. We demonstrate here that we can discriminate between chemicals belonging to different chemical classes including endocrine disruptors, metals and industrial chemicals based on gene expres- sion. We also show that predictive models based on indices of whole pathway transcriptional activity can achieve comparable results while facilitating biological interpretability.
The impact of bisphenol A (BPA) on Gammarus fossarum and Lumbriculus variegatus was studied in four artificial indoor streams (0, 5, 50 and 500 µg L BPA, nominal) over 103 days in a pulse–dose exposure scenario (weekly BPA application). For G. fossarum populations at day 103, the proportions of juveniles and of breeding females from the highest BPA treatment were in tendency reduced. For individually exposed gammarid pairs an EC10 of 17 µg L BPA (nominal) for the proportion of reproductive females in the fourth brood was determined. During the first three broods, the largest brood size occurred at the highest BPA concentration, whereas in the fourth brood it decreased concentration-dependently (fourth brood EC10 = 5 µg L BPA, nominal). Effects on L. variegatus were a reduced population growth (103 d-EC10 of 2 µg L BPA, nominal) and an increase in dry weight and the number of segments in large, complete worms.
We present the first description of intersexes in Gammarus fossarum Koch, 1835 (Amphipoda). Intersexes were found in monthly samples collected in two streams in different regions of Germany. The frequency of intersexuality differed considerably between the populations from the two streams. The Lockwitzbach, located in Sachsen, showed a frequency of 8.8% intersexes, which is much higher compared to the Korsch (located in Baden-Wurttemberg) with 0.6%. In contrast to the Korsch, there were also differences between the two sampling sites in the Lockwitzbach. No seasonal pattern in intersex frequency was observed. Intersexes occurred in all length classes of the adolescent and adult gammarids examined. They were significantly larger than females, but showed no difference in body length compared to males. External sex characteristics of intersex individuals have been described in detail, while in histological analyses of internal sex characteristics ovarian tissue was found exclusively. Microsporidians, parasites often associated with intersexuality, were not detected. The intersexes seemed to be functional females, regarding their ability to breed.
Due to the potential for long-term, low-level exposure of environmental species to pharmaceuticals in the environment, concerns over chronic ecotoxicity have been raised. Pharmaceuticals typically have specific enzyme and receptor-based modes of action, which are extensively studied in mammals during drug development. A survey of the literature demonstrated that there is conservation of many enzyme/receptor systems between mammalian and teleost systems. Based on this conservation of enzyme/receptor systems across teleost species, a model has been developed to utilize the information from mammalian pharmacology and toxicology studies to evaluate the potential for chronic receptor mediated responses in fish. In this model, a measured human therapeutic plasma concentration (HTPC) is compared to a predicted steady state plasma concentration (FSSPC) in fish, and an effect ratio (ER = HTPC/FSSPC) is computed. The lower the ER, the greater the potential for a pharmacological response in fish. Data collection and model validation will strengthen the applicability of this approach as a viable tool for prioritizing research initiatives that examine the potential impact of pharmaceuticals on fish.
Selective serotonin reuptake inhibitors (SSRIs) and tricyclics are commonly prescribed antidepressants in the developed world. The increasing use of such antidepressants coupled with their possible release in municipal sewage effluent creates the potential for physiological and behavioral modification of aquatic organisms. Antidepressants often act by modulating and mimicking the effect of the neurotransmitter serotonin. Since serotonin regulates a wide range of physiological systems, including vasoconstriction in trout, retinomotor activity in sunfishes, larval metamorphosis in snails, reproduction in a variety of molluscs, and ciliary beating in protozoans, drugs that mimic its action could have salient effects on these and other organisms. Laboratory data have shown that several groups of aquatic organisms respond physiologically to applied antidepressants. This review summarizes our current knowledge of the effects of SSRIs, tricyclic antidepressants, and serotonin on the physiology and behavior of aquatic organisms.
The estrogenic properties of many environmental contaminants, such as DDE and PCBs, have been associated with reproductive failure in a variety of vertebrate species. While estrogens have been measured in many invertebrate species, the function of this hormone in invertebrates is controversial. The objective of the present study was to identify possible physiological and biochemical target sites for the estrogenic effects of some xenobiotics on the freshwater crustacean Daphnia magna using the model environmental estrogen diethylstilbestrol (DES). Chronic exposure of daphnids to 0.50 mg/L DES reduced molting frequency among first-generation juveniles and decreased fecundity of second-generation daphnids. Adult first-generation daphnids chronically exposed to DES, as well as adult daphnids acutely exposed to DES for only 48 h, were examined for steroid hormone metabolic capabilities using testosterone as the model steroid. The rate of elimination of two major hydroxylated metabolites of testosterone was significantly reduced, and elimination of glucose conjugates of testosterone was significantly elevated from exposure to 0.50 mg/L DES. These results demonstrate that multigeneration exposure of daphnids to DES results in reduced fecundity and altered steroid metabolic capabilities. Thus, some arthropods, like vertebrates, are sensitive to the effects of endocrine-disrupting chemicals.
Test compounds including natural hormones, endocrine disrupters, environmentally occurringcompounds, and reference compounds were tested for acute toxicity and inhibitory effect on larval development in the copepod Acartia tonsa. Three compounds, 17α-ethinylestradiol, p-octylphenol, and tamoxifen, known for their differing effects on the vertebrate estrogen system, were potent inhibitors of naupliar development. Other estrogens, 17β-estradiol, estrone, and bisphenol A, had little potency. Testosterone and progesterone did not inhibit development, but the antiandrogen flutamide had inhibitory effect. Juvenile hormone III was a potent inhibitor, as was expected based on the literature, whereas 20-hydroxyecdysone had no effect. 3,4-Dichloroaniline was inhibitory on development, whereas other control compounds, potassium dichromate and 3,5-dichlorophenol, did not inhibit development. Six of the 17 test compounds had 50% lethal concentration to 50% effective concentration (EC50) ratios higher than 10. The results suggest that naupliar development, as a parameter, is able to detect hormonal disrupters in addition to other chemicals that have other specific modes of action.
Methoprene is a growth-regulating insecticide that manifests its toxicity to target organisms by acting as a juvenile hormone agonist. Methoprene similarly may exert toxicity to crustaceans by mimicking or interfering with methyl farnesoate, a crustacean juvenoid. We hypothesized that methoprene interferes with endocrine-regulated processes in crustaceans by several mechanisms involving agonism or antagonism of juvenoid receptor complexes. In the present study, we evaluated this hypothesis, in part, by characterizing and comparing the concentration-response curves for methoprene and several endpoints related to development and reproduction of the crustacean Daphnia magna. Our results demonstrate that methoprene has multiple mechanisms of toxicity and low-exposure concentration effects. Methoprene reduced the growth rate of daphnids with evidence of only a single concentration-response line, having a threshold of 12.6 nM. Molt frequency was reduced by methoprene in a concentration-dependent manner, with a response curve corresponding to a 2-segmented line and thresholds at 4.2 and 0.21 nM. An endpoint related to reproductive maturation, the time of first brood deposition, was also affected by methoprene, with a clear concentration-dependent response and a NOEC of 32 nM. Methoprene reduced fecundity according to a 2-segmented line, with thresholds of 24 and ≤0.18 nM. These results demonstrate that methoprene elicits significant toxicity to endocrine-related processes in the 5–50 nM concentration range. Furthermore, molting and reproduction were impacted at significantly lower methoprene concentrations, with a distinct concentration response and a threshold of ≤0.2 nM. The different concentration-dependent response from that of methoprene could involve agonism or antagonism of various juvenoid receptor configurations.
The European Centre for Ecotoxicology and Toxicology of Chemicals proposes a tiered approach for the ecological risk assessment of endocrine disruptors, integrating exposure and hazard (effects) characterization. Exposure assessment for endocrine disruptors should direct specific tests for wildlife species, placing hazard data into a risk assessment context. Supplementing the suite of mammalian screens now under Organization for Economic Cooperation and Development (OECD) validation, high priority should be given to developing a fish screening assay for detecting endocrine activity in oviparous species. Taking into account both exposure characterization and alerts from endocrine screening, higher tier tests are also a priority for defining adverse effects. We propose that in vivo mammalian and fish assays provide a comprehensive screening battery for diverse hormonal functions (including androgen, estrogen, and thyroid hormone), whereas Amphibia should be considered at higher tiers if there are exposure concerns. Higher tier endocrine-disruptor testing should include fish development and fish reproduction tests, whereas a full life-cycle test could be subsequently used to refine aquatic risk assessments when necessary. For avian risk assessment, the new OECD Japanese quail reproduction test guideline provides a valuable basis for developing a test to detecting endocrine-mediated reproductive effects; this species could be used, where necessary, for an avian life-cycle test. For aquatic and terrestrial invertebrates, data from existing developmental and reproductive tests remain of high value for ecological risk assessment. High priority should be given to research into comparative endocrine physiology of invertebrates to support data extrapolation to this diverse fauna.
Regenerative phenomena, which have the advantage of reproducing developmental processes in the adult organism, are very sensitive to environmental stress and represent stages that can be monitored for damage at the whole-organism, cellular and molecular levels. Some persistent and ubiquitous pollutants, which can affect the natural environment because of their bioaccumulation in organisms, exert their effects by acting as 'endocrine disrupters'. In this respect, they can cause dysfunction in steroid hormone production/metabolism and activity by their dramatic effects on gene expression, reproductive competence and growth. The aim of our present research was to assess the impact of such compounds on adult echinoderm reproductive physiology with particular reference to regeneration potential. It is known that vertebrate-type steroids are synthesized by echinoderms and play a role in the control of growth and reproduction. Our experimental model is the crinoid Antedon mediterranea, selected on the basis of its previously explored regenerative capabilities at the level of the arms. The regeneration response, analyzed at the tissue and cellular levels using both light and electron microscopy and immunocytochemistry, was employed to monitor the effects of exposure to persistent endocrine disrupter micropollutants such as polychlorinated biphenyls (PCBs) by means of laboratory tests performed under controlled conditions in terms of environmental variables and contamination levels. Our results indicate that exposure to endocrine disrupter compounds such as PCBs can induce anomalies in regeneration times, morphology and developmental mechanisms that can be interpreted in the light of significant dysfunctions in the endocrine mechanisms controlling regenerative development.
The BII bioassay was developed as a rapid and reliable tool for detecting potential insect growth regulators acting as ecdysteroid receptor (ant)agonists. Based on an ecdysteroid-responsive cell line from Drosophila melanogaster, this microplate assay is ideally suited to the evaluation of environmental contaminants as potential endocrine disrupters. Data are presented for about 80 potential environmental contaminants, including industrial chemicals, pesticides, Pharmaceuticals, phytoestrogens, and vertebrate steroids, and are compared with data for known (ant)agonists. Apart from androst-4-ene-3,17-dione (a weak antagonist), vertebrate steroids were inactive at concentrations up to 10−3 M. The vast majority of xenobiotics also showed no (ant)agonist activity. Among the industrial chemicals, antagonistic activity was observed for bisphenol A median effective concentration (EC50) of 1.0 × 10−4 M and diethylphthalate (EC50 of 2.0 × 10−3 M). Some organochlorine compounds also showed weak antagonistic activity, including o,p′-dichlorodiphenyldichloroethylene (DDE), p,p′-DDE, dieldrin, and lindane (EC50 of 3.0 × 10−5 M). For lindane, bisphenol A, and diethylphthalate, activity is not associated with impurities in the samples and, for lindane and bisphenol A at least, the compounds are able to compete with ecdysteroids for the ligand binding site on the receptor complex, albeit at concentrations very much higher than those found in the environment. The only pharmaceutical showing any detectable antagonist activity was 17α-ethynylestradiol. In the context of recent publications on potential endocrine disruption in marine and freshwater arthropods, these findings suggest that, for some compounds (e.g., diethylstilbestrol), ecdysteroid receptor-mediated responses are unlikely to be involved in producing chronic effects. The BII assay has a potentially valuable role to play in distinguishing between endocrine-mediated, which normally occur at submicromolar concentrations, and pharmacological effects in insects and crustaceans.
Life-cycle effects of a reference ecdysteroid, 20-hydroxyecdysone (20- HEC) and the model xenoestrogen, diethylstilbestrol (DES) in Tisbe battagliai (Crustacea, Copepoda, Harpacticoida) have been evaluated. T. battagliai is a sexually reproducing species that is representative of an ecologically diverse group of aquatic Crustacea and is highly amenable to laboratory life- cycle studies. Newly released (<24-h old) Copepod nauplii were exposed to 20- HEC or DES and effects monitored in terms of survival, development, and sex ratio after 10 d at 20 ± 1°C. A mortality of ≃40% occurred after 9-d exposure to 20-HEC at 269 μg/L, whereas significant (17.5%) mortality (p < 0.05) occurred after 4-d exposure to DES at 100 μg/L. Adult males and females were paired after day 10, and exposures continued to investigate effects on reproductive output (21-d total exposure). In summary, the 21-d LC50 values (with 95% confidence intervals) for 20-HEC and DES were 53.4 μg/L (36.5-78.7) and 31.6 μg/L (10-100), respectively. For 20-HEC, the 21-d no observed effect concentration (NOEC) for survival was 26.9 μg/L, whereas reproduction was a more sensitive endpoint (NOEC = 8.7 μg/L). For DES, survival and reproduction were equally sensitive, and both gave an NOEC value of 10 μg/L (all based on nominal concentrations). These results suggest that the 21-d life-cycle protocol using T. battagliai holds much promise as an in vivo test for developmental and reproductive effects in aquatic Crustacea.
Intense efforts are currently being made to develop procedures to assess the potential for endocrine disruption in aquatic environments. Most attention has focused on fresh water systems, amphibians and fish and morphological and molecular measures for endocrine disruption. A biomarker approach involving the induction of a female-specific protein, vitellogenin, in males by exposure to xeno-oestrogens has proved particularly useful. By contrast marine environments and invertebrates have received comparatively little attention. The present study aimed to examine the effects of exposure to a xeno-oetrogen, 4-n-nonylphenol (4-NP) and a natural oestrogen, 17β-oestradiol (E2) on a marine crustacean, the barnacle Balanus amphitrite. In particular, the effect of such exposure on levels of a larval storage protein, cypris major protein (CMP), which is related to barnacle vitellin, has been examined. Accordingly, nauplius stage larvae of B. amphitrite were exposed to low concentrations (0.01–1.0 μg l−1) of 4-NP and E2 (1.0 μg l−1) from egg hatching until the cypris stage. SDS–PAGE and immunoblotting were used to monitor CMP levels in exposed larvae relative to ‘zero’ concentration controls. Elevated (100% increase) CMP levels were measured in larvae exposed to both 4-NP and E2 at a concentration of 1.0 μg l−1, and notable increases occurred at lower concentrations of 4-NP. It is concluded that CMP and perhaps other vitellin-like proteins are potential biomarkers of low level oestrogen exposure in crustaceans.
The objective of this study was to identify specific physiologic parameters in crustaceans that are targeted by chemicals known to be antiandrogenic in vertebrates. We hypothesized that chemicals capable of binding to the vertebrate androgen receptor would also elicit toxicity to crustaceans by binding to specific steroid hormone receptors in an antagonistic manner. This hypothesis was tested by evaluating the effects of the antiandrogen cyproterone acetate on growth, molting, sexual differentiation, and reproduction of Daphnia magna. Exposure of daphnids to concentrations of cyproterone acetate appreciably below those that elicited mortality reduced growth but had no effect on molting. These concentrations of cyproterone acetate had no effect on various developmental and maturation parameters. Cyproterone acetate also reduced the number of offspring produced by parthenogenetically reproducing daphnids, but this effect appeared to be a consequence of the reduced size of the daphnids and their inability to accommodate a brood of more than approximately 10 eggs. These results indicate that the antiandrogen cyproterone acetate specifically targets a process critical to growth of daphnids that is independent of molting. Additional studies are warranted to established whether this is an endocrine-related toxicity to crustaceans that is associated with environmental antiandrogens such as some pesticide metabolites.
Life-cycle effects of a reference ecdysteroid, 20-hydroxyecdysone (20-HEC) and the model xenoestrogen, diethylstil-bestrol (DES) in Tisbe battagliai (Crustacea, Copepoda, Harpacticoida) have been evaluated. T. battagliai is a sexually reproducing species that is representative of an ecologically diverse group of aquatic Crustacea and is highly amenable to laboratory life-cycle studies. Newly released (<24-h old) Copepod nauplii were exposed to 20-HEC or DES and effects monitored in terms of survival, development, and sex ratio after 10 d at 20 ± 1°C. A mortality of ≈40% occurred after 9-d exposure to 20-HEC at 269 μg/L, whereas significant (17.5%) mortality (p < 0.05) occurred after 4-d exposure to DES at 100 μg/L. Adult males and females were paired after day 10, and exposures continued to investigate effects on reproductive output (21-d total exposure). In summary, the 21-d LC50 values (with 95% confidence intervals) for 20-HEC and DES were 53.4 μg/L (36.5–78.7) and 31.6 μg/L (10–100), respectively. For 20-HEC, the 21-d no observed effect concentration (NOEC) for survival was 26.9 μg/L, whereas reproduction was a more sensitive endpoint (NOEC = 8.7 μg/L). For DES, survival and reproduction were equally sensitive, and both gave an NOEC value of 10 μg/L (all based on nominal concentrations). These results suggest that the 21-d life-cycle protocol using T. battagliai holds much promise as an in vivo test for developmental and reproductive effects in aquatic Crustacea.
This article reviews the field and laboratory evidence for endocrine disruption in gastropod mollusks caused by tributyltin (TBT). Abundant and undisputed field data link TBT with an irreversible sexual abnormality of female neogastropod snails known as “imposex.” This phenomenon is a masculinization process involving the development of male sex organs, notably a penis and a vas deferens; in certain species the imposition of a vas deferens disrupts oviducal structure and function, preventing normal breeding activity and causing population disappearance. In some species, oogenesis is supplanted by spermatogenesis. A related condition referred to as “intersex” has been reported in littorinid mesogastropods, and these too become unable to lay eggs. Field evidence clearly associates these syndromes with the use of TBT as an antifoulant, chiefly on boat hulls, and dose-related effects can be replicated in laboratory exposures to environmentally relevant concentrations of TBT compounds. It has now been established that imposex and intersex are forms of endocrine disruption caused by elevated testosterone titers that masculinize TBT-exposed females. The precise mechanism by which increased levels of testosterone are produced has not been fully described, but the weight of evidence suggests that TBT acts as a competitive inhibitor of cytochrome P450-mediated aromatase. Some recent data suggest that TBT may also inhibit the formation of sulfur conjugates of testosterone and its active metabolites, thus interfering with its excretion. In summary, TBT-induced masculinization in gastropods, imposex and intersex, is the clearest example of endocrine disruption described in invertebrates to date that is unequivocally linked to a specific environmental pollutant.
The estrogenic properties of many environmental contaminants, such as DDE and PCBs, have been associated with reproductive failure in a variety of vertebrate species. While estrogens have been measured in many invertebrate species, the function of this hormone in invertebrates is controversial. The objective of the present study was to identify possible physiological and biochemical target sites for the estrogenic effects of some xenobiotics on the freshwater crustacean Daphnia magna using the model environmental estrogen diethylstilbestrol (DES). Chronic exposure of daphnids to 0.50 mg/L DBS reduced molting frequency among first-generation juveniles and decreased fecundity of second-generation daphnids. Adult first-generation daphnids chronically exposed to DES, as well as adult daphnids acutely exposed to DES for only 48 h, were examined for steroid hormone metabolic capabilities using testosterone as the model steroid. The rate of elimination of two major hydroxylated metabolites of testosterone was significantly reduced, and elimination of glucose conjugates of testosterone was significantly elevated from exposure to 0.50 mg/L DES. These results demonstrate that multigeneration exposure of daphnids to DES results in reduced fecundity and altered steroid metabolic capabilities. Thus, some arthropods, like vertebrates, are sensitive to the effects of endocrine-disrupting chemicals.
Toxicity tests in invertebrates often use sublethal endpoints, which may exhibit different sensitivity for various toxicants. Our objective was to characterize the sensitivity of movement, feeding, growth, and reproduction as endpoints for heavy metal toxicity testing with Caenorhabditis elegans. Growth and feeding were assessed in the same nematode samples used to assess movement and reproduction. Median effective concentrations (EC50s) for 24-h exposures to Pb, Cu, and Cd were determined for movement, feeding, and growth and a 72-h EC50 was derived for reproduction. The order of toxicity was Cu > Pb > Cd for each endpoint, including lethality and movement. There were no differences in sensitivity among endpoints for any metal. When exposed for 4 h at (sublethal) concentrations that were 14 times the 24-h EC50 value, Pb and Cu reduced feeding to the same extent while movement was reduced significantly more by Pb than by Cu. Thus, a difference in sensitivity of endpoints was apparent at 4 h, which was not evident at 24 h. These observations suggest potentially different mechanisms of toxicity for 24- and 4-h tests.
There is increasing concern about pharmaceuticals and personal care products ( PPCPs) during the last decade due to their environmental occurrence and potential physiological effects. These compounds can be continually discharged into the environment primarily via untreated and treated sewage since current wastewater treatment plant can not completely remove them. This results in chronic low concentration exposure of aquatic organisms by PPCPs , which potentially hazard the ecological system and human health. This paper reviews current studies on the environmental analytical methods , occurrence , fates in the wastewater treatment process , potential ecological impacts , and preliminary risk assessment of PPCPs.
In many vertebrates, environmental factors influence gamete differentiation and growth of the mature gonad through alteration of sex steroid production or action; however, it is unclear how gamete differentiation and gonadal growth are regulated in echinoids. The purpose of this study was to examine the influence of dietary administration of estradiol (E2), progesterone (P4), testosterone (T) and finasteride (F, a 5α-reductase inhibitor) on the ovaries and testes of mature Lytechinus variegatus (Lamarck) during gonadal growth. Echinoids were fed a formulated diet supplemented with steroids or steroids in combination with finasteride for 36 d. The effects of dietary administration of steroids on L. variegatus were both steroid- and sex-specific. The mean ovary index was 54% greater in individuals fed E2 than from individuals fed the control (C) diet (10.0 ± 1.1 vs 6.5 ± 0.7, respectively; P
Organotins, and more specifically tributyltins (TBT), are introduced into the marine environment by paints designed to protect ship hulls against biological fouling. Lab tests have shown that bivalve reproduction is affected by TBT concentrations exceeding 20 ngl–1. A dose-effect correlation scale describes the effects on embryogenesis and on larval growth: total larval mortality occurs after 12 days of exposure at a concentration of 200 ngl–1, and inhibition of fertilization at 100 gl–1. At concentrations close to 1 ngl–1, significant changes are observed in the sexuality of marine gastropods, reflected in an imposition of male characters in females, a phenomenon known as imposex. Imposex evolution in Nucella lapillus females includes: formation of a vas deferens, a channel between prostate and penis existing in males (phase 1), appearance and growth of a penis (phases 2 to 4), sterilization of the subject with blocking of the oviduct and accumulation of eggs within the gland (phases 5 to 6). In the final stages, females become sterile, thereby jeopardizing population renewal. These disturbances occur following exposure at TBT concentrations of 7 to 12 ngl–1 approximately. Physiological and biochemical phenomena leading to imposex are still not well understood. However, there are evidences that TBT exposure tends to increase the testosterone contents in female mollusks, while progesterone and 17 E oestradiol levels remain constant. Since testosterone alone causes penis growth in the females, it is thought that imposex could be attributed to its accumulation originating from inhibition of cytochrome P450-dependent aromatase. The conversion of testosterone into 17 E oestradiol would then be inhibited by TBT. In spite of regulations banning the use of TBT as biocide in antifouling paints, current TBT contamination in coastal areas frequently reaches concentrations likely to cause imposex.
The present study examines the effect of a known environmental oestrogen, 4-nonylphenol, on the settlement of the cypris larva of the barnacle, Balanus amphitrite. Cypris larvae were exposed to 4-nonylphenol in a nominal concentration range of 0.01–10.0 μg l−1. Definitive concentrations of 4-nonylphenol in the test solutions were determined by GC/MS. Cyprid settlement was reduced significantly within this concentration range, following incubation at both 25°C and 28°C for 24–48 h. A naturally occurring oestrogen, 17β oestradiol, was used as a positive control, in the concentration range 0.01–10.0 μg l−1. Larval settlement was inhibited by 17β oestradiol, but the trend was the opposite to that seen with 4-nonylphenol. No evidence of endocrine disruption was demonstrated, but significant inhibition of larval settlement by both 4-nonylphenol and 17β oestradiol indicated that the compounds may have toxic effects at environmentally realistic and naturally occurring concentrations. The potential for endocrine disruption being more significant at different developmental stages in barnacles is discussed.
The marine copepod Tisbe battagliai was exposed to the endocrine disrupter nonylphenol (31–500 μg l−1) in two life-table experiments. Data on fecundity, longevity, and rate of development were used to calculate the population growth rate (rm) for exposed and unexposed cohorts of copepods. The highest concentrations tested (125 and 500 μg l−1 nonylphenol) were acutely lethal to the nauplii. When the copepods were exposed to 62 μg l−1 nonylphenol, only 6% survived to maturity. The surviving copepods, however, produced enough F1 and F2 offspring to increase the size of the population compared to the P-generation. There were no statistically significant effects on any life table parameter for T. battagliai at 31 μg l−1 nonylphenol, although rm was reduced in one of the experiments mainly due to reduced survival to maturity. There was no statistically significant change in the percentage of female in neither the P (parent) nor the F1 (offspring) generation exposed to 31 μg l−1 NP compared to the controls.
Given recent reports suggesting that natural and synthetic steroids (namely, oestradiol, oestrone and ethynylestradiol) may be present in sewage effluent at levels which may impact on fish, it is pertinent to extend the ecological hazard evaluation for such substances to aquatic invertebrates. Studies have therefore been undertaken to address whether 17β-oestradiol, oestrone and 17α-ethynylestradiol can inhibit survival, development or reproductive output in Tisbe battagliai (Crustacea, Copepoda, Harpacticoida). This sexually reproducing species was selected since it is representative of a widespread group of aquatic Crustacea, is sensitive to environmental contaminants and is highly amenable to laboratory life-cycle studies. Newly released (<24 h old) T. battagliai nauplii were exposed to individual steroids dissolved in sea water (using the ecdysteroid, 20-hydroxyecdysone, as a positive control) and effects monitored in terms of survival, development and sex ratio after 10 days at 20±1°C. Adult males and females were then paired and exposures continued to investigate effects on reproductive output (21 days total exposure). In summary, the lowest 21 day No Observed Effect Concentrations based on these life-cycle parameters were: 20-hydroxyecdysone: 8.7 μg·l−1; oestrone: ≥100 μg·l−1; 17β-oestradiol: ≥100 μg·l−1; and 17α-ethynylestradiol: ≥100 μg·l−1 (all based on nominal concentrations). These data are relevant for the development of an ecological risk assessment for oestrogenic steroids in the aquatic environment and should be extended to other invertebrate groups. As novel analytical techniques allow, future bioassay studies should be ideally supported by steroid analyses wherever possible.
Phase I and phase II chemical detoxication processes were elucidated in Daphnia magna using in vivo techniques and [14C]testosterone as a substrate. Testosterone was used because this compound undergoes multiple biotransformations and its metabolites are well characterized in other species. In addition, regulation of these processes by the endogenous steroid hormone, 20-hydroxyecdysone, was investigated. Daphnids produced at least ten polar phase I metabolites and four nonpolar phase I metabolites of testosterone. Six of the ten polar metabolites have been identified as monohydroxy-products of testosterone. The polar metabolites were preferentially excreted while the nonpolar metabolites were preferentially retained by the daphnids. In addition, testosterone and all phase I metabolites were also excreted as glucose conjugates. A polar metabolite designated ‘C’ was preferentially conjugated with glucose over the other metabolites. Testosterone and its polar phase I metabolites were also excreted as sulfate conjugates with 2α-hydroxytestosterone being the predominant sulfate-conjugated metabolite. In contrast to glucose conjugation, no nonpolar phase I metabolites of testosterone were sulfate conjugated. Twenty-four hour pre-exposure of daphnids to 4.2 μM 20-hydroxyecdysone did not affect phase I metabolism of testosterone, but differentially modulated phase II conjugation in a manner suggesting the presence of at least two glucosyltransferases and two sulfotransferases. Treatment with 20-hydroxyecdysone significantly increased the elimination of sulfate conjugates due largely to increased sulfate conjugation of unmetabolized testosterone. These results demonstrate that daphnids can convert polycyclic compounds to multiple polar and nonpolar metabolites resulting from both phase I and phase II biotransformations, and that some phase II activities are under the regulatory control of 20-hydroxyecdysone.
Evidence from field studies shows that mouthpart deformities in chironomid larvae are a sublethal response to pollution. Interest has been shown to use this end-point in programs for monitoring sediment quality. During laboratory studies, however, deformities were induced in only a few single pollutant exposures. These deformities develop at the endocrine regulated molting stage and disruption of this complex process is likely at the base of their ontogeny. Aiming to clarify the processes involved in the rise of such deformities, we tested the effects of ethynylestradiol (EE2) in an in vivo lab study. Chironomus riparius larvae were exposed to 1, 10 and 100 μg l−1 EE2 (nominal concentrations). No adverse effects on the larvae, for the investigated end-points (survival and deformity induction), were found.
The purpose of this study is to develop an in vitro assay for screening drug and their effects on membrane fusion and lysis of intracellular organelles.
A 96-well microtiter-dish turbidimetric assay using membrane components of the eggs of sea urchins, a marine invertebrate, was applied to monitor granule fusion and/or lysis.
Of 18 drugs screened, 16 had no effect. One antineoplastic drug, tamoxifen, disrupted intracellular membranes in a calcium independent manner. Taxol, another antineoplastic drug, specifically inhibited calcium triggered exocytosis.
This assay is inexpensive, simple, rapid, and does not require the sacrifice of animal life. It has the potential to identify drugs that are membrane active, as well as those which specifically perturb events involved in the secretion process.
Endocrine disrupting chemicals are a newly defined category of environmental contaminants that may affect animal and human populations by interfering with normal hormone action. There is substantial concern that these agents could have a range of subtle and long-lasting effects. Because of the sensitivity of the developing central nervous system to low levels of endogenous gonadal hormones during development, the central nervous system may be a target for the action of endocrine disrupting chemicals.
Many wildlife species may be exposed to biologically active concentrations of endocrine-disrupting chemicals. There is strong evidence obtained from laboratory studies showing the potential of several environmental chemicals to cause endocrine disruption at environmentally realistic exposure levels. In wildlife populations, associations have been reported between reproductive and developmental effects and endocrine-disrupting chemicals. In the aquatic environment, effects have been observed in mammals, birds, reptiles, fish, and mollusks from Europe, North America, and other areas. The observed abnormalities vary from subtle changes to permanent alterations, including disturbed sex differentiation with feminized or masculinized sex organs, changed sexual behavior, and altered immune function. For most reported effects in wildlife, however, the evidence for a causal link with endocrine disruption is weak or nonexisting. Crucial in establishing causal evidence for chemical-induced wildlife effects appeared semifield or laboratory studies using the wildlife species of concern. Impaired reproduction and development causally linked to endocrine-disrupting chemicals are well documented in a number of species and have resulted in local or regional population changes. These include: Masculinization (imposex) in female marine snails by tributyltin, a biocide used in antifouling paints, is probably the clearest case of endocrine disruption caused by an environmental chemical. The dogwhelk is particularly sensitive, and imposex has resulted in decline or extinction of local populations worldwide, including coastal areas all over Europe and the open North Sea. DDE-induced egg-shell thinning in birds has caused severe population declines in a number of raptor species in Europe and North America. Endocrine-disrupting chemicals have adversely affected a variety of fish species. In the vicinity of certain sources (e.g., effluents of water treatment plants) and in the most contaminated areas is this exposure causally linked with the effects on reproductive organs that could have implications for fish populations. However, there is also a more widespread occurrence of endocrine disruption in fish in the U.K., where estrogenic effects have been demonstrated in freshwater systems, in estuaries, and in coastal areas. In mammals, the best evidence comes from the-field studies on Baltic gray and ringed seals, and from the Dutch semifield studies on harbor seals, where both reproduction and immune functions have been impaired by PCBs in the food chain. Reproduction effects resulted in population declines, whereas impaired immune function has likely contributed to the mass mortalities due to morbillivirus infections. Distorted sex organ development and function in alligators has been related to a major pesticide spill into a lake in Florida, U.S.A. The observed estrogenic/antiandrogenic effects in this reptile have been causally linked in experimental studies with alligator eggs to the DDT complex. Although most observed effects currently reported concern heavily polluted areas, endocrine disruption is a potential global problem. This is exemplified by the widespread occurrence of imposex in marine snails and the recent findings of high levels of persistent potential endocrine-disrupting chemicals in several marine mammalian species inhabiting oceanic waters.
The antiestrogen tamoxifen (TAM) is widely used as a drug against breast cancer and is currently being tested as a chemopreventive agent. However, a number of studies showed genotoxic and carcinogenic effects of TAM. These effects are thought to be related to oxygen radical overproduction which occurs during TAM metabolic activation. There is no evidence, thus far, on TAM toxicity to embryos and gametes. The present study was designed to elucidate the mechanisms of TAM-induced developmental, reproductive and cytogenetic toxicity towards sea urchin (SU) embryos with regard to the possibility of TAM-initiated oxidative stress. Embryo cultures from SU were subjected to long-term (throughout embryogenesis) or short-term (two hours) incubation with TAM at concentrations from 10(-8) to 10(-5) M. The experiments on TAM-induced toxicity to gametes were carried out with SU sperm, or unfertilized eggs, suspended in TAM (10(-8) to 10(-6) M). To assess the effects of TAM to embryos or to gametes, developmental defects, embryonic mortality, fertilization success, and cytogenetic abnormalities were scored. Oxidative damage to DNA and lipids was detected by measurements of 8OHdG levels and lipid peroxidation, respectively. Reactive oxygen species (ROS) production by eggs and embryos was recorded by luminol-dependent chemiluminescence (LDCL) and cytochrome c reduction methods. The changes in activities of SU superoxide dismutase (SOD) and catalase were also evaluated. TAM exerted: a) early embryonic mortality to exposed embryos and to the offspring of exposed eggs; b) developmental defects to the offspring of exposed sperm; c) decrease in sperm fertilization success, and d) cytogenetic effects in the offspring of exposed sperm or eggs. These morphological effects corresponded to the state of oxidative stress in SU embryos (increased oxidative damage to DNA and lipids and induction of antioxidant enzymes). Since TAM did increase significantly ROS production by embryos, it is suggested that TAM may be metabolically activated by SU embryonic oxidases and peroxidases, which in turn could be induced by TAM. The present study provides further support to the utilization of the SU system as a useful model to help elucidate mechanisms of chemical teratogenesis and carcinogenesis.
Toxicity tests in invertebrates often use sublethal endpoints, which may exhibit different sensitivity for various toxicants. Our objective was to characterize the sensitivity of movement, feeding, growth, and reproduction as endpoints for heavy metal toxicity testing with Caenorhabditis elegans. Growth and feeding were assessed in the same nematode samples used to assess movement and reproduction. Median effective concentrations (EC50s) for 24-h exposures to Pb, Cu, and Cd were determined for movement, feeding, and growth and a 72-h EC50 was derived for reproduction. The order of toxicity was Cu > Pb > Cd for each endpoint, including lethality and movement. There were no differences in sensitivity among endpoints for any metal. When exposed for 4 h at (sublethal) concentrations that were 14 times the 24-h EC50 value, Pb and Cu reduced feeding to the same extent while movement was reduced significantly more by Pb than by Cu. Thus, a difference in sensitivity of endpoints was apparent at 4 h, which was not evident at 24 h. These observations suggest potentially different mechanisms of toxicity for 24- and 4-h tests.
Exposure of Daphnia pulex to the insecticide and juvenile hormone-mimic methoprene resulted in a decrease in the incidence of all-male broods and an increase in the incidence of all-female broods compared with controls. These effects were observed at nominal concentrations of 10 and 100 microg/L, within the upper range of concentrations at which methoprene is applied in the environment. Because methoprene has been found to bind to the mammalian retinoid X receptor, we also tested the effects of retinoic acid on Daphnia reproduction. Neither 9-cis-retinoic acid nor all-trans-retinoic acid had any observable effect. Because juvenile hormone and ecdysteroids interact in many insect systems, we also exposed Daphnia to 20-OH-ecdysone. Exposure to the crustacean hormone 20-OH-ecdysone at levels of 1 and 10 microg/L resulted in an increase in all-male broods and a decrease in all-female broods, but 100 microg/L 20-OH-ecdysone resulted in a decrease in all-male broods and an increase in all-female broods. Our results suggest that juvenile hormone and ecdysteroids might play a role in the Daphnia sex determination system.
Increasing numbers of widely used industrial, agricultural, and natural chemicals are known to elicit endocrine-disrupting effects in a wide range of vertebrate and invertebrate species. The objective of this study was to determine whether the sexual development of the freshwater crustacean Gammarus pulex (L.) was affected below sewage treatment works (STW) previously known to contain endocrine-disrupting chemicals in their effluent. The gonadal structure, external sexual characteristics, and size of gammarids from exposed sites were compared to those of gammarids from a reference site. No significant difference was found in the gonadal structure of males collected below two STW. However, a highly significant number of females collected from a site known to elicit high estrogenic responses in vertebrates displayed an abnormal structure of oocytes in vitellogenesis. Body size was significantly shorter and male/female size differential was significantly reduced below one of the STW. Analysis of gnathopod and genital papillae length data suggests that different allometric relationships of these organs to body size exist between sample sites.
The B(II) bioassay was developed as a rapid and reliable tool for detecting potential insect growth regulators acting as ecdysteroid receptor (ant)agonists. Based on an ecdysteroid-responsive cell line from Drosophila melanogaster, this microplate assay is ideally suited to the evaluation of environmental contaminants as potential endocrine disrupters. Data are presented for about 80 potential environmental contaminants, including industrial chemicals, pesticides, pharmaceuticals, phytoestrogens, and vertebrate steroids, and are compared with data for known (ant)agonists. Apart from androst-4-ene-3,17-dione (a weak antagonist), vertebrate steroids were inactive at concentrations up to 10(-3) M. The vast majority of xenobiotics also showed no (ant)agonist activity. Among the industrial chemicals, antagonistic activity was observed for bisphenol A median effective concentration (EC50) of 1.0 x 10(-4) M and diethylphthalate (EC50 of 2.0 x 10(-3) M). Some organochlorine compounds also showed weak antagonistic activity, including o,p'-dichlorodiphenyldichloroethylene (DDE), p,p'-DDE, dieldrin, and lindane (EC50 of 3.0 x 10(-5) M). For lindane, bisphenol A, and diethylphthalate, activity is not associated with impurities in the samples and, for lindane and bisphenol A at least, the compounds are able to compete with ecdysteroids for the ligand binding site on the receptor complex, albeit at concentrations very much higher than those found in the environment. The only pharmaceutical showing any detectable antagonist activity was 17alpha-ethynylestradiol. In the context of recent publications on potential endocrine disruption in marine and freshwater arthropods, these findings suggest that, for some compounds (e.g., diethylstilbestrol), ecdysteroid receptor-mediated responses are unlikely to be involved in producing chronic effects. The B(II) assay has a potentially valuable role to play in distinguishing between endocrine-mediated, which normally occur at submicromolar concentrations, and pharmacological effects in insects and crustaceans.
In recent years, reports have described endocrine-disruptive effects of environmental oestrogens in fish, but little is known about similar effects in crustaceans. The objective of the present study was therefore to examine whether the oestrogens 17-beta-oestradiol, 17-alpha-ethynylestradiol and diethylstilbestrol (DES), could affect mortality, larval development rate, fecundity and sex ratio in the sexually reproducing harpacticoid copepod Nitocra spinipes. Newly released nauplii (<24-h old) were exposed to 1/1,000, 1/100 and 1/10 (nominal concentrations) of each oestrogen's 96 h-LC50 value for < or = 18 days at 22 +/- 1 degrees C. The percentage of gravid females and the number of developed copepodites were both reduced at 0.03 mg l(-1) DES, although the latter response was not significant. None of the other two oestrogens induced any measurable effects. Since the only observed significant response appeared at a DES concentration no more than 10 times below the 96 h-LC50 value, there is no evidence of endocrine-disruptive activity in N. spinipes exposed to oestrogens.
The effects of the environmental estrogen 17alpha-ethinylestradiol (EE) on mixed populations of 90 individual Gammarus pulex were examined following a 100-d exposure in a flow-through system. Counts of total animal numbers revealed that, in all treatment groups, population size dramatically increased due to recruitment, with neonate and juvenile gammarids the most abundant. At concentrations of 1 and 10 microg/L EE, the recorded mean population sizes of 385 and 411, respectively, were significantly greater (p = 0.018) than the control (169). Mean population sizes in the solvent control (257) and 100 ng/L EE treatment (267) were not significantly different (p > 0.05) from the control. In addition to total counts, detailed image analysis of each individual animal allowed the assessment of length-frequency distributions, adult sex ratio, number of precopula pairs/ovigerous females, and measurement of secondary antenna and gnathopod length (secondary sex characteristics). The sex ratio of adults at 100 ng, 1 microg, and 10 microg/L EE was greater than 2:1 (female:male), and significantly more females (p = 0.008) were recorded at these concentrations compared with the control. The number of male adults, precopula guarding pairs, and ovigerous females did not differ between treatments (p > 0.05). Secondary antennal and gnathopod length in males was consistently greater than in females (p < or = 0.001), but comparison between groups revealed no difference in these parameters.
Antidepressants in aquatic organisms: a wide range of effects Pharmaceuticals and Personal Care Products in the Environment —Scientific and Regulatory Issues
- P P Fong
Fong, P.P., 2001. Antidepressants in aquatic organisms: a wide range of effects. In: Daughton, C.G., Jones-Lepp, T.L. (Eds.), Pharmaceuticals and Personal Care Products in the Environment —Scientific and Regulatory Issues. American Chemistry Society, Washington DC, p. 396 ACS Sympo-sium Series 791.
Laboratory toxicity tests for evaluating potential effects of endocrine disrupting compounds
- C G Ingersoll
- T H Hutchinson
- M Crane
- S Dodson
- T Dewitt
- A Gies
- M.-C Huet
- C L Mckenney
- E Oberdörster
- D Pascoe
- D J Versteeg
- O Warwick
Ingersoll, C.G., Hutchinson, T.H., Crane, M., Dodson, S.,
DeWitt, T., Gies, A., Huet, M.-C., McKenney, C.L., Oberdö rster, E., Pascoe, D., Versteeg, D.J., Warwick, O., 1999.
Laboratory toxicity tests for evaluating potential effects of
endocrine disrupting compounds. In: DeFur, P., Crane,
M., Ingersoll, C., Tattersfield, L. (Eds.), Endocrine Disruption in Invertebrates: Endocrinology, Testing and Assessment. Proceedings of the EDIETA Workshop. SETAC
Technical Publications Series ISBN 1-880611-27-9, 107 -197.
Steroid hormone-regulated processes in invertebrates and their susceptibility to environmental endocrine disruption
- LeBlanc
LeBlanc, G.A., 1999. Steroid hormone-regulated processes in
invertebrates and their susceptibility to environmental endocrine disruption. In: Guillette, L., Crain, D.A. (Eds.),
Environmental Endocrine Disruption: An Evolutionary
Perspective. Taylor and Francis, New York, pp. 126 -154.
The Diversity of Life. Penguin, London, p. 406. Further Reading In vivo biotransforma-tion of testosterone by phase I and II detoxification en-zymes and their modulation by 20-hydroxyecdysone in Daphnia magna
- E O Wilson
- W S Baldwin
- G A Leblanc
Wilson, E.O., 1999. The Diversity of Life. Penguin, London, p. 406. Further Reading Baldwin, W.S., LeBlanc, G.A., 1994. In vivo biotransforma-tion of testosterone by phase I and II detoxification en-zymes and their modulation by 20-hydroxyecdysone in Daphnia magna. Aquat. Toxicol. 29, 103 – 117.
- E P Solomon
- L R Berg
- D W Martin
- C Villee
Solomon, E.P., Berg, L.R., Martin, D.W., Villee, C., 1996.
Biology, fourth ed. Saunders College Publishing, New
York.
- P Defur
- M Crane
- C Ingersoll
DeFur, P., Crane, M., Ingersoll, C., Tattersfield, L. (Eds.),
1999. Endocrine Disruption in Invertebrates: Endocrinology, Testing and Assessment. SETAC, Pensacola, FL SE-TAC Technical Publications Series ISBN 1-880611-27-9.
European workshop on the impact of endocrine disrupters on human health and wildlife
European Commission, 1996. European workshop on the impact of endocrine disrupters on human health and wildlife.
Report of Proceedings from a Workshop held in Weybridge, UK, 2 -4 December 1996. Report reference EUR
17549, European Commission, DGXII, Brussels, Belgium.
Impact of ecdysteroids and oestrogens on developmental and reproductive parameters in the marine copepod Tisbe battagliai
- Hutchinson