Evidence for endocrine disruption in invertebrates

Cadmium and phthalate impacts developmental growth and mortality of Spodoptera littoralis, but not reproductive success

Our environment is increasingly polluted with various molecules, some of which are considered endocrine disruptors. Metals and phthalates, originating from industrial activities, agricultural practices, or consumer products, are prominent examples of such pollutants. We experimentally investigated the impacts of the heavy metal cadmium and the phthalate DEHP on the moth Spodoptera littoralis. More specifically, larvae were reared in laboratory conditions, where they were exposed to diets contaminated with either two doses of cadmium at concentrations of 62.5 µg/g or 125 µg/g, two doses of DEHP at 100 ng/g and 10 µg/g, or a combination of both low and high doses of the two compounds, with a control group for comparison. Our findings indicate that cadmium delays the developmental transition from larva to adult. Notably, the combination of cadmium and DEHP exacerbated this delay, highlighting a synergistic effect. In contrast, DEHP alone did not affect larval development. Additionally, we observed that cadmium exposure, both alone and in combination with DEHP, led to a lower mass at all larval stages. However, cadmium-exposed individuals that reached adulthood eventually reached a similar mass to those in other groups. Interestingly, while our results did not show any effect of the treatments on hatching success, there was a higher adult mortality rate in the cadmium-treated groups. This suggests that while moths may prioritize reproductive success, their survival at the adult stage is compromised by cadmium exposure. In conclusion, our study demonstrates the impact of cadmium on the development, mass, and adult survival of moths, and reveals synergistic effects when combined with DEHP. These results confirm cadmium as an endocrine disruptor, even at low doses. These insights underscore the importance of understanding the toxicological effects of low doses of pollutants like cadmium and DEHP, both individually and in combination.

Impact of single and combined exposure to priority pollutants on gene expression and post-embryonic development in Drosophila melanogaster

Many priority pollutants are concentrated in the environment due to human activity. Most are highly toxic to various organisms, including endocrine disruptors EDCs, aromatic polycyclic hydrocarbons PAHs, pesticides. While the effects of single and binary exposure have been widely explored, several pollutants can be simultaneously present at the same time in the environment, in in more or less polluted matrices. Effective pollution control requires the presence and sources of contamination to be identified. Previously we used Drosophila melanogaster to investigate metal pollution. Here, we re-used Drosophila to identify the biomarkers of pollution, and to determine if they can be used for specific types of pollution. Single and combined exposure of Bis(2-ethylhexyl) phthalate (DEHP), bisphenol A, nonylphenol, benzo(a)pyrene, and glyphosate was investigated. The impact of these pollutants on post-embryonic development and the expression pattern of 38 molecular targets were examined using qPCR. During single exposure, different profiles were observed at the molecular level. In complex mixtures, the expression profile resembled that of bisphenol A. In contrast, relatively specific gene expression profiles were obtained for the effects of each pollutant separately. While direct pollutant-gene profiling remains difficult in mixtures, molecular biology analyses enhance pollution monitoring, and should be incorporated in toxicological studies.

Isolation of Environmental Bacteria Able to Degrade Sterols and/or Bile Acids: Determination of Cholesterol Oxidase and Several Hydroxysteroid Dehydrogenase Activities in Rhodococcus, Gordonia, and Pseudomonas putida

Interest about the isolation and characterization of steroid-catabolizing bacteria has increased over time due to the massive release of these recalcitrant compounds and their deleterious effects or their biotransformation derivatives as endocrine disruptors for wildlife, as well as their potential use in biotechnological approaches for the synthesis of pharmacological compounds. Thus, in this chapter, an isolation protocol to select environmental bacteria able to degrade sterols, bile acids, and androgens is shown. Moreover, procedures for the determination of cholesterol oxidase or different hydroxysteroid dehydrogenase activities in Pseudomonas putida DOC21, Rhodococcus sp. HE24.12, Gordonia sp. HE24.4J and Gordonia sp. HE24.3 are also detailed.

Drosophila ecdysone receptor activity-based ex vivo assay to assess the endocrine disruption potential of environmental chemicals

Insect pollinators, critical for both agricultural output and the ecosystem, are declining at an alarming levels partly due to human-made chemicals. Majority of environmental chemicals hamper the endocrine function and studies on the same in insects remain neglected. Here, we report a Drosophila-based ex vivo assay system that employs a reproductive tissue from transgenic males carrying a reporter gene (lacZ) downstream of ecdysone receptor response element (EcRE) and permits the evaluation of chemical-mediated activity modulation of all three isoforms of ecdysone receptor, which are critical for male fertility. We show agonistic [plasticizers, cypermethrin, atrazine, methyl parathion, imidacloprid, cadmium chloride, mercuric chloride or 3-(4-methylbenzylidene) camphor] or antagonistic (apigenin, tributyltin chloride) effects or lack of effect thereof (rutin hydrate, dichlorvos, lead acetate, parabens) for seven different classes of environmental chemicals on ecdysone receptor activity reflecting the specificity and sensitivity of the developed ex vivo assay. Exposure to a few of these chemicals in vivo hampers the fertility of Drosophila males, thus linking the observed endocrine disruption to a quantifiable reproductive phenotype. The developed ex vivo assay offers a quick Drosophila-based screening tool for throughput monitoring of environmental chemicals for their ability to hamper the endocrine function of insect pollinators and other invertebrates.

One planet: one health. A call to support the initiative on a global science-policy body on chemicals and waste

The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science-policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science-policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science-policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health.

A critical review on various remediation approaches for heavy metal contaminants removal from contaminated soils

Heavy metal pollution remains a global environmental challenge that poses a significant threat to human life. Various methods have been explored to eliminate heavy metal pollutants from the environment. However, most methods are constrained by high expenses, processing duration, geological problems, and political issues. The immobilization of metals, phytoextraction, and biological methods have proven practical in treating metal contaminants from the soil. This review focuses on the general status of heavy metal contamination of soils, including the excessive heavy metal concentrations in crops. The assessment of the recent advanced technologies and future challenges were reviewed. Molecular and genetic mechanisms that allow microbes and plants to collect and tolerate heavy metals were elaborated. Tremendous efforts to remediate contaminated soils have generated several challenges, including the need for remediation methodologies, degrees of soil contamination, site conditions, widespread adoptions and various possibilities occurring at different stages of remediation are discussed in detail.

Crustaceans, One Health and the changing ocean

Crustaceans permeate every habitat on Earth but are especially impactful in the marine environment. They can be small and extremely abundant like the ubiquitous marine copepods found throughout the world's oceans, or large and highly prized by fishermen like spiny lobsters found in tropical and temperate seas, globally. The latter are among the decapod crustaceans, a group which includes crabs, shrimps, and lobsters - those targeted most commonly by fishery and aquaculture industries. Hence, crustaceans are ecologically important, but they are also directly linked to the economic and nutritional health of human populations. To most effectively manage and conserve crustacean populations in the face of a changing ocean environment, whether they are harvested or not, requires a One Health approach that underscores the linkages between crustacean, human, and environmental health. Here, we give an overview of the need, benefits, and challenges to taking the One Health approach to crustacean health and argue that when viewed through the One Health lens, there is perhaps no other group of marine animals more worthy of that perspective.

Microbial degradation of steroid sex hormones: implications for environmental and ecological studies

Steroid hormones modulate development, reproduction and communication in eukaryotes. The widespread occurrence and persistence of steroid hormones have attracted public attention due to their endocrine-disrupting effects on both wildlife and human beings. Bacteria are responsible for mineralizing steroids from the biosphere. Aerobic degradation of steroid hormones relies on O2 as a co-substrate of oxygenases to activate and to cleave the recalcitrant steroidal core ring. To date, two oxygen-dependent degradation pathways - the 9,10-seco pathway for androgens and the 4,5-seco pathways for oestrogens - have been characterized. Under anaerobic conditions, denitrifying bacteria adopt the 2,3-seco pathway to degrade different steroid structures. Recent meta-omics revealed that microorganisms able to degrade steroids are highly diverse and ubiquitous in different ecosystems. This review also summarizes culture-independent approaches using the characteristic metabolites and catabolic genes to monitor steroid biodegradation in various ecosystems.

Invertebrates facing environmental contamination by endocrine disruptors: Novel evidences and recent insights

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.

In Situ Reproductive Bioassay with Caged Gammarus fossarum (Crustacea): Part 1-Gauging the Confounding Influence of Temperature and Water Hardness

Monitoring the adverse effects of environmental contaminants on the reproduction of invertebrate species in the field remains a challenge in aquatic ecotoxicology. To meet the need for reliable tools for in situ toxicity assessment, we present the first part of a methodological study of the in situ implementation of a reproductive bioassay in Gammarus previously developed for screening the toxicity of chemical compounds during laboratory exposure. To ensure the correct interpretation of the modulation of reproductive markers (molting, fecundity, follicle growth, and embryonic development) in uncontrolled environmental conditions, we experimentally assessed and statistically modeled the variability in the female reproductive cycle during laboratory exposure under several temperature and water hardness conditions. Whereas water hardness did not influence the reproductive cycle, the significant accelerating effect of temperature on the dynamics of molting and marsupial development was finely modeled, by detailing the influence of temperature on the probability of transition between all molt and embryonic stages along the female cycle. In addition, no effect of temperature or water hardness was detected on the number of oocytes and embryos carried by females. Furthermore, the finding that the relative durations of the first 4 molt and embryonic stages are constant whatever the temperature makes it possible to predict the molting dynamics in fluctuating temperature conditions. Because this could allow us to take into account the confounding influence of temperature on the measurement of reproductive markers, the implications of these findings for an optimal in situ implementation of the reproductive bioassay with G. fossarum are discussed. The relevance of this modeling approach during in situ implementation is tested in a companion study. Environ Toxicol Chem 2020;39:667-677. © 2019 SETAC.

Tributyltin reduces bone mineral density by reprograming bone marrow mesenchymal stem cells in rat

Tributyltin (TBT), a proven endocrine disrupter, was widely used in industry and agriculture. Previous research showed that TBT could alter the balance between osteogenesis and adipogenesis, which may have significant consequences for bone health. Herein, we exposed male rats to TBT chloride (TBTCl) to evaluate the deleterious effects of TBT on bone. Exposure to 50 μg kg^-1 TBT resulted in a significant decrease in bone mineral density (BMD) at the femur diaphysis region in the rat. A dose-dependent increase in lipid accumulation and adipocyte number was observed in the bone marrow (BM) of the femur. Meanwhile, TBTCl treatment significantly enhanced the expression of PPARγ and attenuated the expression of Runx2 and β-catenin in BM. In addition, serum ALP activity of TBT-exposed rats also showed a dose-dependent decrease. These results suggest that TBT could reduce BMD via inhibition of the Wnt/β-catenin pathway and skew the adipo-osteogenic balance in the BM of rats.

The evolutionary road to invertebrate thyroid hormone signaling: Perspectives for endocrine disruption processes

Thyroid hormones (THs) are the only iodine-containing hormones that play fundamental roles in chordates and non-chordates. The chemical nature, mode of action and the synthesis of THs are well established in mammals and other vertebrates. Although thyroid-like hormones have been detected in protostomes and non-chordate deuterostomes, TH signaling is poorly understood as compared to vertebrates, particularly in protostomes. Therefore, the central objective of this article is to review TH system components and TH-induced effects in non-vertebrate chordates, non-chordate deuterostomes and protostomes based on available genomes and functional information. To accomplish this task, we integrate here the available knowledge on the THs signaling across non-vertebrate chordates, non-chordate deuterostomes and protostomes by considering studies encompassing TH system components and physiological actions of THs. We also address the possible interactions of thyroid disrupting chemicals and their effects in protostomes and non-chordate deuterostomes. Finally, the perspectives on current and future challenges are discussed.

Efficacy of Spinosad Granules and Lambda-Cyhalothrin Contrasts with Reduced Performance of Temephos for Control of Aedes spp. in Vehicle Tires in Veracruz, Mexico

The present study examined the efficacy of λ-cyhalothrin, pyriproxyfen and granular formulations of spinosad and temephos for the control of mosquito larvae present in experimental tires in Veracruz State, Mexico in the period 2015-2016. Both λ-cyhalothrin and spinosad granules provided control of larvae and pupae of Aedes aegypti, Ae. albopictus and Culex spp. in used tires in Veracruz State, Mexico, over a 9-12 week period, although numbers of Culex were low. The numbers of Aedes larvae + pupae in pyriproxyfen and temephos-treated tires were slightly less than half of the untreated control tires, probably a result the pupicidal characteristics of pyriproxyfen and possible resistance in the case of temephos. Spinosad was less harmful to predatory Toxorhynchites spp. than λ-cyhalothrin or temephos. The reduced susceptibility to temephos in Aedes populations was confirmed at five other sites in Veracruz. Public health authorities should consider incorporating spinosad as a larvicide in coastal areas at a high risk of dengue, chikungunya and Zika outbreaks in this region.

Lymnaea stagnalis as a freshwater model invertebrate for ecotoxicological studies

Lymnaea stagnalis, also referred to as great or common pond snail, is an abundant and widespread invertebrate species colonizing temperate limnic systems. Given the species importance, studies involving L. stagnalis have the potential to produce scientifically relevant information, leading to a better understanding of the damage caused by aquatic contamination, as well as the modes of action of toxicants. Lymnaea stagnalis individuals are easily maintained in laboratory conditions, with a lifespan of about two years. The snails are hermaphrodites and sexual maturity occurs about three months after egg laying. Importantly, they can produce a high number of offspring all year round and are considered well suited for use in investigations targeting the identification of developmental and reproductive impairments. The primary aims of this review were two-fold: i) to provide an updated and insightful compilation of established toxicological measures determined in both chronic and acute toxicity assays, as useful tool to the design and development of future research; and ii) to provide a state of the art related to direct toxicant exposure and its potentially negative effects on this species. Relevant and informative studies were analysed and discussed. Knowledge gaps in need to be addressed in the near future were further identified.

Reproductive Impact of Environmental Chemicals on Animals

Wildlife is exposed to a diverse range of natural and man-made chemicals. Some environmental chemicals possess specific endocrine disrupting properties, which have the potential to disrupt reproductive and developmental process in certain animals. There is growing evidence that exposure to endocrine disrupting chemicals plays a key role in reproductive disorders in fish, amphibians, mammals, reptiles and invertebrates. This evidence comes from field-based observations and laboratory based exposure studies, which provide substantial evidence that environmental chemicals can cause adverse effects at environmentally relevant doses. There is particular concern about wildlife exposures to cocktails of biologically active chemicals, which combined with other stressors, may play an even greater role in reproductive disorders than can be reproduced in laboratory experiments. Regulation of chemicals affords some protection to animals of the adverse effects of exposure to legacy chemicals but there continues to be considerable debate on the regulation of emerging pollutants.

Tandem Action of Natural and Chemical Stressors in Stream Ecosystems: Insights from a Population Genetic Perspective

Agricultural and urban land use has dramatically increased over the last century and one consequence is the release of anthropogenic chemicals into aquatic ecosystems. One of the rarely studied consequences is the effect of land use change on internal concentrations of organic micropollutants (OMPs) in aquatic invertebrates and its effects on their genotype diversity. Here, we applied population genetic and internal concentrations of OMPs analyses to determine evolutionary implications of chemical pollution on Gammarus pulex populations from a natural and two agricultural streams. Along 14 consecutive months sampled, 26 different OMPs were quantified in G. pulex extracts with the highest number, concentration, and toxic pressure in the anthropogenically stressed stream ecosystems. Our results indicate distinct internal OMP profiles and changes in both genetic variation and genetic structure in streams affected by anthropogenic activity. Genetic variation was attributed to chemical pollution whereas changes in the genetic structure were attributed to environmental disturbances, such as changes in discharge in the impacted stream ecosystems, which worked both independently and in tandem. Finally, we conclude that human-impacted streams are subjected to severe alterations in their population genetic patterns compared to nonimpacted stream ecosystems.

Identification, expression, and endocrine-disruption of three ecdysone-responsive genes in the sentinel species Gammarus fossarum

Taking advantage of a large transcriptomic dataset recently obtained in the sentinel crustacean amphipod Gammarus fossarum, we developed an approach based on sequence similarity and phylogenetic reconstruction to identify key players involved in the endocrine regulation of G. fossarum. Our work identified three genes of interest: the nuclear receptors RXR and E75, and the regulator broad-complex (BR). Their involvement in the regulation of molting and reproduction, along with their sensitivity to chemical contamination were experimentally assessed by studying gene expression during the female reproductive cycle, and after laboratory exposure to model endocrine disrupting compounds (EDCs): pyriproxyfen, tebufenozide and piperonyl butoxide. RXR expression suggested a role of this gene in ecdysis and post-molting processes. E75 presented two expression peaks that suggested a role in vitellogenesis, and molting. BR expression showed no variation during molting/reproductive cycle. After exposure to the three EDCs, a strong inhibition of the inter-molt E75 peak was observed with tebufenozide, and an induction of RXR after exposure to pyriproxyfen and piperonyl butoxide. These results confirm the implication of RXR and E75 in hormonal regulation of female reproductive cycles in G. fossarum and their sensitivity towards EDCs opens the possibility of using them as specific endocrine disruption biomarkers.

Resource efficiency analysis for photocatalytic degradation and mineralization of estriol using TiO2 nanoparticles

A resource efficiency analysis was developed that evaluated photocatalyst loading and temperature inputs, and assessed hydroxyl radical (OH) production. Catalyst loading (Aeroxide^® TiO₂ P25) between 1 and 1500 mg L^-1 and temperatures between 5 and 50 °C were analyzed as input resources for OH production. After, the best experimental conditions were used to degrade and mineralize estriol (E3). The analysis showed that a low catalyst concentration lead to poor absorption of radiation and a slow reaction. When high catalyst concentrations were tested, most of the radiation was absorbed, which produced results near the top of the slowing rate of OH generation. Temperature was found a relevant resource for increasing interfacial transfer to facilitate OH production following the Arrhenius model. Two indices to measure resource efficiency were proposed: 1) the OH generation index (OHI) and 2) the initial degradation efficiency (IDE). OHI was used to measure the efficiency of a catalyst using photonic flux to generate OH production. IDE evaluated the relationship between the photocatalytic reactor set-up, catalyst, and E3 degradation. It was observed that 1.18 OH was produced when a photon interacts with a photocatalyst particle when a load of 5 mg L^-1 of photocatalyst is used at 20 °C. It was found that at initial time, 2.4 OH was generated in the systems to produce a degradation of one E3 molecule when using a photocatalyst load of 20 mg L^-1 at 20 °C. Additionally, it was demonstrated that E3 mineralization was feasible under different catalyst loading scenarios.

Spermatogenic Cycle and Steroidogenic Control of Spermatogenesis in Mytilus galloprovincialis Collected in the Bay of Naples

The aim of the present article was to study the spermatogenic cycle of Mytilus galloprovincialis collected in the Bay of Naples during a whole year and to acquire new insights into the mechanism of control. Knowledge of the Mytilus cycle in this geographic area is of particular interest as, to the best of our knowledge, the male gonad cycle has been hitherto unexplored. Testis organization was evaluated together with the localization of the enzymes 3β-HSD, 17β-HSD, and P450-aromatase, which are strictly connected to the synthesis of two key hormones involved in the testis activity: testosterone and 17β-estradiol. It was demonstrated that: (1) the spermatogenic cycle starts in late Summer-early Fall and continues until early Winter, when the first spawning occurs; after rapid gonad restoration, several spawning events take place until June, when the testis becomes non-active again; (2) in the testis, true Leydig and Sertoli cells are present; (3) during the reproductive period, Sertoli, Leydig, germ, and adipogranular cells (ADGs) are positive to 3β-HSD and 17β-HSD, while only germ cells are positive to P450 aromatase; by contrast, during the resting period, only ADGs are positive to 3β-HSD and 17β-HSD, and P450-aromatase is no longer recognizable. The presence of a hermaphrodite sample is also described. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1881-1894, 2017. © 2017 Wiley Periodicals, Inc.

A field study of hemolymph yolk protein levels in a bivalve (Unio tumidus) and future considerations for bivalve yolk protein as endocrine biomarker

Induction of yolk protein in male fish is a recognized biomarker for estrogenic exposure because the estrogen-dependent induction mechanism is well investigated and there is a clear difference in yolk protein levels of unexposed males and females. Attempts have been made to use induction of bivalve yolk protein as biomarker for estrogenic exposure. However, several biomarker validation criteria have not yet been investigated e.g. an in-depth understanding of the induction mechanism and background variability is needed and reliable detection assays are yet to be developed. To obtain background knowledge about yolk protein levels freshwater bivalves (Unio tumidus) were collected in an uncontaminated Danish lake over the course of a year (33 collection dates). The hemolymph yolk protein concentration of 569 individuals was determined by a species specific enzyme-linked immunosorbent assay (ELISA) and male and female gonadal development cycles were established. The average yolk protein levels of males and females collected at each sampling date overlapped in some periods; the male and female range was 66,946 - 169,692 ng/mL and 88,731 - 681,667 ng/mL, respectively. Because male and female hemolymph yolk protein levels overlap, great care should be taken if yolk protein induction in bivalve hemolymph is considered as endocrine biomarker.

Multilevel ecotoxicity assessment of environmentally relevant bisphenol A concentrations using the soil invertebrate Eisenia fetida

Bisphenol A (BPA) presents a serious threat to soil ecosystems, yet its effects on soil-inhabiting organisms are mostly unexplored. Therefore, the impact of environmentally relevant BPA concentrations on a terrestrial model organism, the earthworm Eisenia fetida, was assessed. Animals were cutaneously exposed to 100nM and 10μM BPA up to 10days (10-d). Next, a battery of biomarkers was used for ecotoxicological evaluation on a cellular, tissue and behavioural level. HPLC analysis showed that after a 10-d exposure, BPA accumulation reached a maximum of 2.50μg BPA per g of wet tissue weight. On the cellular level, up to 3-d BPA exposure caused increased lipid oxidation indicating oxidative stress. Histopathological assessment of cell wall and ovaries after 7- and 10-d BPA exposure showed multiple abnormalities, i.e. hyperplasia of epidermis, increased body wall thickness and ovarian atrophy. Detection of these changes was facilitated by a newly proposed semi-quantitative scoring system. Finally, behavioural changes were detected after only 3days of exposure to 100nM BPA. Altogether, the presented multilevel toxicity evaluation indicates high sensitivity of earthworms to low BPA doses.

Body burden of pesticides and wastewater-derived pollutants on freshwater invertebrates: Method development and application in the Danube River

While environmental risk assessment is typically based on toxicant concentrations in water and/or sediment, awareness is increasing that internal concentrations or body burdens are the key to understand adverse effects in organisms. In order to link environmental micropollutants as causes of observed effects, there is an increasing demand for methods to analyse these chemicals in organisms. Here, a multi-target screening method based on pulverised liquid extraction (PuLE) and a modified QuEChERS approach with an additional hexane phase was developed. It is capable to extract and quantify organic micropollutants of diverse chemical classes in freshwater invertebrates. The method was tested on gammarids from the Danube River (within the Joint Danube Survey 3) and target compounds were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Furthermore, a non-target screening using high resolution-tandem mass spectrometry (LC-HRMS/MS) was conducted. A total of 17 pollutants were detected and/or quantified in gammarids at low concentrations. Pesticide concentrations ranged from 0.1 to 6.52 ng g(-1) (wet weight), those of wastewater-derived pollutants from 0.1 to 2.83 ng g(-1) (wet weight). The presence of wastewater-derived pollutants was prominent at all spots sampled. Using non-target screening, we could successfully identify several chlorinated compounds. These results demonstrate for the first time the presence of pesticides and wastewater-derived pollutants in invertebrates of the Danube River.

The endocrine disruptor effect of the herbicides atrazine and glyphosate on Biomphalaria alexandrina snails

Atrazine (AZ) and glyphosate (GL) are herbicides that are widely applied to cereal crops in Egypt. The present study was designed to investigate the response of the snailBiomphalaria alexandrina(Mollusca: Gastropoda) as a bioindicator for endocrine disrupters in terms of steroid levels (testosterone (T) and 17β-estradiol (E)), alteration of microsomal CYP4501B1-like immunoreactivity, total protein (TP) level, and gonadal structure after exposure to sublethal concentrations of AZ or GL for 3 weeks. In order to study the ability of the snails' recuperation, the exposed snails were subjected to a recovery period for 2 weeks. The results showed that the level of T, E, and TP contents were significantly decreased (p ≤ 0.05) in both AZ- and GL-exposed groups compared with control (unexposed) group. The level of microsomal CYP4501B1-like immunoreactivity increased significantly (p ≤ 0.05) in GL- and AZ-exposed snails and reach nearly a 50% increase in AZ-exposed group. Histological investigation of the ovotestis showed that AZ and GL caused degenerative changes including azoospermia and oocytes deformation. Interestingly, all the recovered groups did not return back to their normal state. It can be concluded that both herbicides are endocrine disrupters and cause cellular toxicity indicated by the decrease of protein content and the increase in CYP4501B1-like immunoreactivity. This toxicity is irreversible and the snail is not able to recover its normal state. The fluctuation of CYP4501B1 suggests that this vertebrate-like enzyme may be functional also in the snail and may be used as a biomarker for insecticide toxicity.

Sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages

Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (EE2), simultaneously in three deeply divergent systematic anuran families, a model-species, Xenopus laevis (Pipidae), and two non-models, Hyla arborea (Hylidae) and Bufo viridis (Bufonidae). Our new approach combines synchronized tadpole exposure to three EE2-concentrations (50, 500, 5,000 ng/L) in a flow-through-system and pioneers genetic and histological sexing of metamorphs in non-model anurans for EDC-studies. This novel methodology reveals striking quantitative differences in genetic-male-to-phenotypic-female sex reversal in non-model vs. model species. Our findings qualify molecular sexing in EDC-analyses as requirement to identify sex reversals and state-of-the-art approaches as mandatory to detect species-specific vulnerabilities to EDCs in amphibians.

Elucidation of the role of estradiol and progesterone in regulating reproduction in the edible crab, Oziothelphusa senex senex

Vertebrate sex steroids are ubiquitous and important bioactive mediators for many physiological functions.

The uptake and bioaccumulation of heavy metals by food plants, their effects on plants nutrients, and associated health risk: a review

Heavy metal contamination is a globally recognized environmental issue, threatening human life very seriously. Increasing population and high demand for food resulted in release of various contaminants into environment that finally contaminate the food chain. Edible plants are the major source of diet, and their contamination with toxic metals may result in catastrophic health hazards. Heavy metals affect the human health directly and/or indirectly; one of the indirect effects is the change in plant nutritional values. Previously, a number of review papers have been published on different aspects of heavy metal contamination. However, no related information is available about the effects of heavy metals on the nutritional status of food plants. This review paper is focused upon heavy metal sources, accumulation, transfer, health risk, and effects on protein, amino acids, carbohydrates, fats, and vitamins in plants. The literature about heavy metals in food plants shows that both leafy and nonleafy vegetables are good accumulators of heavy metals. In nonleafy vegetables, the bioaccumulation pattern was leaf > root ≈ stem > tuber. Heavy metals have strong influence on nutritional values; therefore, plants grown on metal-contaminated soil were nutrient deficient and consumption of such vegetables may lead to nutritional deficiency in the population particularly living in developing countries which are already facing the malnutrition problems.

Perinatal exposure to low doses of tributyltin chloride reduces sperm count and quality in mice

Exposure to endocrine disruptors (EDs) during early development might lead to adverse health outcomes later in life. Tributyltin (TBT), a proven ED, is widely used in consumer goods and industrial products. Herein we demonstrate the effects of low doses of tributyltin chloride (TBTCl) on reproduction of male KM mice. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. TBTCl dramatically decreased sperm counts and motility on postnatal days (PNDs) 49 and 152. Meanwhile, a significant increase in sperm abnormality was observed in exposed mice on PND 49, but comparable to that in the control on PND 152. The histopathological analysis of testes of treated animals showed a dose-dependent increase in sloughing of germ cells in seminiferous tubules. Mice treated with 10 μg TBTCl/kg exhibited decreased intratesticular 17β-estradiol (E2) levels on PND 49, and then followed by an obvious recovery on PND 152. While, no significant differences in serum E2, testosterone (T) levels and intratesticular T levels were detectable between control and TBTCl-exposed offspring at the sacrifice. These results suggest that perinatal TBTCl exposure is implicated in causing long lasting alterations in male reproductive system and these changes may persist far into adulthood.

Ethylparaben affects lifespan, fecundity, and the expression levels of ERR, EcR and YPR in Drosophila melanogaster

Parabens, which mainly include methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP), are widely used as cosmetic and food preservatives. Although these chemicals, when used as preservatives, are thought to be safe for humans, many studies have demonstrated that they have estrogenic effects, and can affect the normal development and functions of the reproductive systems in a number of animal species. By treating fruit flies (Drosophila melanogaster) with EP, here we show that lower concentration of EP (0.02%) enhanced fertility while higher concentration of EP (0.10% and 0.20%) shortened the lifespan and reduced the fecundity of fruit flies. When we analyzed the expression levels of the estrogen-related receptor gene (ERR), ecdysone receptor gene (EcR) and Yolk protein receptor gene (YPR) from control and EP-treated fruit flies by using quantitative real-time PCR, we found that the expression levels of all three genes were significantly changed by EP treatment, and that female fruit flies are more sensitive to EP than males. Our data suggests that the estrogenic and the toxic effects of EP to fruit flies may have a molecular basis through the hormonal effect of EP.

Seasonal variations of gene expression biomarkers in Mytilus galloprovincialis cultured populations: temperature, oxidative stress and reproductive cycle as major modulators

The blue mussel Mytilus galloprovincialis has been used as monitoring organism in many biomonitoring programs because of its broad distribution in South European sea waters and its physiological characteristics. Different pollution-stress biomarkers, including gene expression biomarkers, have been developed to determine its physiological response to the presence of different pollutants. However, the existing information about basal expression profiles is very limited, as very few biomarker-based studies were designed to reflect the natural seasonal variations. In the present study, we analyzed the natural expression patterns of several genes commonly used in biomonitoring, namely ferritin, metallothionein, cytochrome P450, glutathione S-transferase, heat shock protein and the kinase responsive to stress KRS, during an annual life cycle. Analysis of mantle-gonad samples of cultured populations of M. galloprovincialis from the Delta del Ebro (North East Spain) showed natural seasonal variability of these biomarkers, pointing to temperature and oxidative stress as major abiotic modulators. In turn, the reproductive cycle, a process that can be tracked by VCLM7 expression, and known to be influenced by temperature, seems to be the major biotic factor involved in seasonality. Our results illustrate the influence of environmental factors in the physiology of mussels through their annual cycle, a crucial information for the correct interpretation of responses under stress conditions.

Effect of 17α-hydroxyprogesterone and 17α-hydroxypregnenolone on sperm quality and sperm quantity in male mud spiny lobster (Panulirus polyphagus)

The present study aimed to determine the effect of 17α-hydroxyprogesterone (17α-OHP) and 17α-hydroxypregnenolone (17α-OHPL) on sperm quality and sperm quantity in male mud spiny lobster (Panulirus polyphagus). The mean of sperm quality was increased in 17α-OHP and 17α-OHPL treated hormones. In 17α-OHP injected animals, the mean of sperm quantity of dose 0.01 μg g(-1) b.wt. was increased than 17α-OHPL. Meanwhile, 17α-OHP and 17α-OHPL concentrations were lower when injected with the hormones but 17α-OHP was higher at only day 15 (dose 0.01 and 0.1 μg g(-1) b.wt.). For 17α-OHPL, the hormone was a prohormone in the body of P. polyphagus and only required smaller to increase the sperm quantity. Besides, when the higher dose of 17α-OHPL (0.1 μg g(-1) b.wt.) was used in P. polyphagus, the development of P. polyphagus was inhibited and decreased the sperm quantity and 17α-OHPL concentration in hemolymph was lower. Injection of 17α-OHP in P. polyphagus has increased the sperm quality and quantity for both 17α-OHP dosage of 0.01 and 0.1 μg g(-1) b.wt. However, injection of 17α-OHPL in P. polyphagus has decreased the sperm quantity only, also for both dosage of 0.01 and 0.1 μg g(-1) b.wt. and lower on hormone concentration.

Effect of testosterone undecanoate hormone on sperm and its level in the hemolymph of male mud spiny lobster, Panulirus polyphagus

The present study aimed to determine the effect of testosterone undecanoate hormone on sperm quality (sperm viability) and sperm quantity (sperm counts) and its levels in the hemolymph of male mud spiny lobster, Panulirus polyphagus. Male P. polyphagus was injected laterally in fifth abdominal segment of pure hormone, Testosterone Undecanoate (TU) and ethanol at days 1, 8, 15, 22 and 29. Hemolymph of P. polyphagus was taken every two weeks and checked with Enzyme-linked immunosorbent assay (ELISA) to measure hormone levels. The mean sperm quality and quantity were increased due to increase the TU dose and TU levels also increase. The sperm quality, quantity and hormone levels were relevance each others. These findings indicate that TU injection should be evaluated as a practical way of improving sperm quality and quantity in commercial operations.

Metabolomic, behavioral, and reproductive effects of the synthetic estrogen 17 α-ethinylestradiol on the unionid mussel Lampsilis fasciola

The endocrine disrupting effects of estrogenic compounds in surface waters on fish, such as feminization of males and altered sex ratios, may also occur in aquatic invertebrates. However, the underlying mechanisms of action and toxicity, especially in native freshwater mussels (Order Unionoida), remain undefined. This study evaluated the effects of a 12-day exposure of 17 α-ethinylestradiol (EE2), a synthetic estrogen in oral contraceptives commonly found in surface waters, on the behavior, condition, metabolism, and reproductive status of Lampsilis fasciola. Adult mussels of both sexes were exposed to a control and two concentrations of EE2 (0 ng/L, 5 ng/L considered to be environmentally relevant, and 1,000 ng/L designed to provide a positive metabolic response), and samples of gill tissue were taken on days 4 and 12; gills were used because of the variety of critical processes they mediate, such as feeding, ion exchange, and siphoning. Observations of mussel behavior (mantle display, siphoning, and foot movement) were made daily, and condition of conglutinates (packets of eggs and/or glochidia) released by females was examined. No significant effects of EE2 on glochidia mortality, conglutinate condition, female marsupial gill condition, or mussel foot extension were observed. However, exposure to both concentrations of EE2 significantly reduced male siphoning and mantle display behavior of females. Metabolomics analyses identified 207 known biochemicals in mussel gill tissue and showed that environmentally relevant EE2 concentrations led to decreases in glycogen metabolism end products, glucose, and several essential fatty acids in females after 12 days, indicating reductions in energy reserves that could otherwise be used for growth or reproduction. Moreover, males and females showed significant alterations in metabolites involved in signal transduction, immune response, and neuromodulation. Most of these changes were apparent at 1,000 ng/L EE2, but similar metabolites and pathways were also affected at 5 ng/L EE2. Components of the extracellular matrix of gill tissue were also altered. These results demonstrate the utility of metabolomics when used in conjunction with traditional physiological and behavioral toxicity test endpoints and establish the usefulness of this approach in determining possible underlying toxicological mechanisms of EE2 in exposed freshwater mussels.

Adult exposure to the synthetic hormone 17α-ethynylestradiol affects offspring of the gastropods Nassarius burchardi and Nassarius jonasii

The aim of this study was to determine whether adult exposure to endocrine disrupting compounds affects offspring using trans-generational testing. Adult estuarine dwelling gastropods Nassarius burchardi and Nassarius jonasii were exposed to the synthetic estrogen 17α-ethynylestradiol (EE2) to determine the effects on the development and survival of their offspring. Adults were maintained in synthetic seawater controls and EE2 treatments (0.005, 0.05, 0.5, 50µg/L) over a sixteen week period. Egg capsules were collected from the adults following four, ten and sixteen weeks of adult exposure and transferred to different EE2 exposure scenarios. Treatment concentrations were selected to represent changes in EE2 exposure that could occur over different periods in an organism's lifecycle. Egg capsules laid by adults were therefore transferred to control or EE2 treatments (0.005, 0.05, 0.5, 5, 50, 500µg/L) to develop until hatching. The percentage of egg capsules with unviable eggs and abnormalities, number of days for hatching to occur and hatching success were measured. The veliger larvae that hatched from egg capsules following two, eight and fourteen weeks of adult exposure to EE2 and controls were used in 96h acute toxicity tests with controls and EE2 treatments at concentrations of 0.5, 5, 50, 500, 1250, 2500, 4000µg/L. Exposure of adult N. burchardi and N. jonasii to EE2 affected the percentage of egg capsules with unviable eggs, the development and hatching success of embryos and survival of veligers. These toxicity tests produced a complex set of results with different responses in developing eggs and veliger larvae to the adult EE2 treatments and length of adult exposure. This study demonstrates the importance of trans-generational testing and adult exposure scenarios in toxicity investigations.

In situ effects of urban river pollution on the mudsnail Potamopyrgus antipodarum as part of an integrated assessment

The freshwater mudsnail (Potamopyrgus antipodarum) is sensitive to toxicity of both sediment and water and also to the endocrine disrupting compounds (EDC) at environmentally relevant concentrations. This study determined effects of in situ exposure of P. antipodarum as a part of a complex assessment of the impact of a city metropolitan area with large waste water treatment plant (WWTP) for 0.5 million population equivalents on two urban rivers. The study combined the in situ biotest with detailed chemical analyses and a battery of in vitro bioassays of both sediment and water. Passive sampling of river water was conducted during the course of exposure of the mudsnail. P. antipodarum was exposed for 8 weeks in cages permeable to sediment and water at localities up- and down-stream of the city of Brno, Czech Republic and downstream of the WWTP in two rivers. Greater mortality and significantly decreased embryo production of P. antipodarum were observed immediately downstream of the city of Brno. P. antipodarum exposed at locations downstream of the metropolitan area and WWTP exhibited greater mortality, while numbers of embryos produced by surviving individuals were comparable or slightly greater than for individuals held at the least polluted location. Comparisons with results of chemical analysis and in vitro assays indicate occurrence of groups of compounds contributing to observed effects. Differences in mortalities of mudsnails among sites corresponded well with in vitro cytotoxicity and concentrations of metals. The results of this study confirm the applicability of this novel field biotest with P. antipodarum for the evaluation of the effects of river pollution on metazoans, especially as suitable in situ part of integrative contamination assessment.

Vestigialization of an allosteric switch: genetic and structural mechanisms for the evolution of constitutive activity in a steroid hormone receptor

An important goal in molecular evolution is to understand the genetic and physical mechanisms by which protein functions evolve and, in turn, to characterize how a protein's physical architecture influences its evolution. Here we dissect the mechanisms for an evolutionary shift in function in the mollusk ortholog of the steroid hormone receptors (SRs), a family of biologically essential transcription factors. In vertebrates, the activity of SRs allosterically depends on binding a hormonal ligand; in mollusks, however, the SR ortholog (called ER, because of high sequence similarity to vertebrate estrogen receptors) activates transcription in the absence of ligand and does not respond to steroid hormones. To understand how this shift in regulation evolved, we combined evolutionary, structural, and functional analyses. We first determined the X-ray crystal structure of the ER of the Pacific oyster Crassostrea gigas (CgER), and found that its ligand pocket is filled with bulky residues that prevent ligand occupancy. To understand the genetic basis for the evolution of mollusk ERs' unique functions, we resurrected an ancient SR progenitor and characterized the effect of historical amino acid replacements on its functions. We found that reintroducing just two ancient replacements from the lineage leading to mollusk ERs recapitulates the evolution of full constitutive activity and the loss of ligand activation. These substitutions stabilize interactions among key helices, causing the allosteric switch to become “stuck” in the active conformation and making activation independent of ligand binding. Subsequent changes filled the ligand pocket without further affecting activity; by degrading the allosteric switch, these substitutions vestigialized elements of the protein's architecture required for ligand regulation and made reversal to the ancestral function more complex. These findings show how the physical architecture of allostery enabled a few large-effect mutations to trigger a profound evolutionary change in the protein's function and shaped the genetics of evolutionary reversibility.

An important goal in evolutionary genetics is to understand how genetic mutations cause the evolution of new protein functions and how a protein's structure shapes its evolution. Here we address these questions by studying a dramatic lineage-specific shift in function in steroid hormone receptors (SRs), a physiologically important family of transcription factors. In vertebrates, SRs bind hormones and then undergo a structural change that allows them to activate gene expression. In mollusks, SRs do not bind hormone and are always active. We identified the genetic and structural mechanisms for the evolution of constitutive activity in the mollusk SRs by using X-ray crystallography, ancestral sequence reconstruction, and experimental studies of the effects of ancient mutations on protein structure and function. We found that constitutive activity evolved due to just two historical substitutions that subtly stabilized elements of the active conformation, and subsequent mutations filled the hormone-binding cavity. The structural characteristics required for a hormone-sensitive activator were thus vestigialized, much the same way that a whale's hindlimbs became vestiges of their ancestral form after they became dispensable. Our findings show how the architecture of a protein can shape its evolution, allowing radically different functions to evolve by a few large-effect mutations.

Occurrences and fate of selected human antibiotics in influents and effluents of sewage treatment plant and effluent-receiving river Yamuna in Delhi (India)

Antibiotics consumption has increased worldwide, and their residues are frequently reported in aquatic environments. It is believed that antibiotics reach aquatic water bodies through sewage. Medicine consumed for healthcare practices are often released into sewage, and after sewage treatment plant, it reaches the receiving water bodies of lakes or rivers. In the present study, we determined the fate of some commonly used antibiotics in a sewage treatment plant (STP) located in Delhi and the environmental concentration of these antibiotics in the Yamuna River, which receives the sewage and industrial effluent of Delhi. There are many reports on antibiotics occurrences in STP and river water worldwide, but monitoring data from the Indian subcontinent is sparse. Samples were taken from a STP and from six sampling sites on the Yamuna River. Several antibiotics were tested for using offline solid-phase extraction followed by high-performance liquid chromatography equipped with photodiode array analysis. Recoveries varied from 25.5-108.8 %. Ampicillin had the maximum concentration in wastewater influents (104.2 ± 98.11 μg l(-1)) and effluents (12.68 ± 8.38 μg l(-1)). The fluoroquinolones and cephalosporins had the lower concentrations. Treatment efficiencies varied between 55 and 99 %. Significant amounts of antibiotics were discharged in effluents and were detected in the receiving water body. The concentration of antibiotics in the Yamuna River varied from not detected to 13.75 μg l(-1) (ampicillin) for the compounds investigated.

Impact of environmental estrogens on Yfish considering the diversity of estrogen signaling

Research on endocrine disruption in fish has been dominated by studies on estrogen-active compounds which act as mimics of the natural estrogen, 17β-estradiol (E2), and generally exert their biological actions by binding to and activation of estrogen receptors (ERs). Estrogens play central roles in reproductive physiology and regulate (female) sexual differentiation. In line with this, most adverse effects reported for fish exposed to environmental estrogens relate to sexual differentiation and reproduction. E2, however, utilizes a variety of signaling mechanisms, has multifaceted functions and targets, and therefore the toxicological and ecological effects of environmental estrogens in fish will extend beyond those associated with the reproduction. This review first describes the diversity of estrogen receptor signaling in fish, including both genomic and non-genomic mechanisms, and receptor crosstalk. It then considers the range of non-reproductive physiological processes in fish that are known to be responsive to estrogens, including sensory systems, the brain, the immune system, growth, specifically through the growth hormone/insulin-like growth factor system, and osmoregulation. The diversity in estrogen responses between fish species is then addressed, framed within evolutionary and ecological contexts, and we make assessments on their relevance for toxicological sensitivity as well as ecological vulnerability. The diversity of estrogen actions raises questions whether current risk assessment strategies, which focus on reproductive endpoints, and a few model fish species only, are protective of the wider potential health effects of estrogens. Available - although limited - evidence nevertheless suggests that quantitative environmental threshold concentrations for environmental protection derived from reproductive tests with model fish species are protective for non-reproductive effects as well. The diversity of actions of estrogens across divergent physiological systems, however, may lead to and underestimation of impacts on fish populations as their effects are generally considered on one functional process only and this may underrepresent the impact on the different physiological processes collectively.

Bisphenol A migration from plastic materials: direct insight of ecotoxicity in Daphnia magna

Bisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children's exposure to BPA has been emphasized because of the immaturity of their biological systems. The main aim of this study was to assess the reproductive impact of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring species Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological test results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (neonates per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1 ± 4.3 % to 264.7 ± 3.8 %), both in single as in multigenerational tests, in comparison with the negative control group (100.3 ± 1.6 %). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, neonate production by daphnids cultured in polypropylene and non-PC bottles was slightly but not significantly enhanced (92.5 ± 2.0 % to 118.8 ± 1.8 %). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results could be given: a non-monotonic dose-response relationship or a mixture toxicity effect.

Low field-relevant tebufenozide concentrations affect reproduction in Chironomus riparius (Diptera: Chironomidae) in a long-term toxicity test

A few studies reporting the effects of tebufenozide, a non-steroidal ecdysone agonist that mimics natural moulting hormones in chironomids exist in the literature. However, nothing is known about its chronic or multigenerational effects on the reproduction of aquatic insects, although tebufenozide is present in aquatic ecosystems. Here, we investigated the chronic toxicity of tebufenozide in two successive generations of Chironomus riparius using nominal concentrations that ranged from 4 to 26.2 μg/L. We started the test from the first instar larvae in the parental (P) generation, quantifying life cycle parameters (emergence, sex ratio, development rate, fecundity and fertility) until the emergence in the subsequent F1 generation. Results showed a reduction in reproduction and a significant decrease in male developmental rate of midges for all treatments, in the F1 generation compared with the P generation (paired t test; p<0.001). Two-way analysis of variance revealed a significant exposure × generation effect on male fraction with male fraction increasing (P generation) or decreasing (F1 generation) with increasing exposure. These effects on C. riparius underline the importance of conducting long-term studies with environmentally relevant concentrations to investigate population-level endpoints for endocrine disrupting chemicals.

Heavy metal concentrations in edible barnacles exposed to natural contamination

The giant barnacle Megabalanus azoricus is a popular seafood in the Azores. It is mainly caught in coastal environments and sold for domestic human consumption. This species is a filter feeder and can be used as a biomonitor of trace metal bioavailabilities. To investigate consumption safety, the concentrations of 10 trace metals - As, Cd, Cr, Cu, Mn, Pb, Rb, Se, Sr and Zn - were evaluated in 3 body tissues of M. azoricus from 3 sites on 2 islands. There were no significant differences between the metal loads of the barnacles from the different sites. However, the concentrations of the total trace metal loads revealed significant differences among the tissues (cirrus, muscles and ovaries). The concentrations of some metals in the body were not within the safety levels for consumers, based on the allowable standard levels for crustaceans issued by the European Union and of legislations in several countries. Alarming levels of As and Cd were found. Considering the absence of heavy industry in the region, a non-anthropogenic volcanic source was assumed to be the reason for the observed metal levels. Barnacles, in particular M. azoricus, seem to be useful as bioindicators in this peculiar environment.

Protozoa interaction with aquatic invertebrate: interest for watercourses biomonitoring

Toxoplasma gondii, Cryptosporidium parvum, and Giardia duodenalis are human waterborne protozoa. These worldwide parasites had been detected in various watercourses as recreational, surface, drinking, river, and seawater. As of today, water protozoa detection was based on large water filtration and on sample concentration. Another tool like aquatic invertebrate parasitism could be used for sanitary and environmental biomonitoring. In fact, organisms like filter feeders could already filtrate and concentrate protozoa directly in their tissues in proportion to ambient concentration. So molluscan shellfish can be used as a bioindicator of protozoa contamination level in a site since they were sedentary. Nevertheless, only a few researches had focused on nonspecific parasitism like protozoa infection on aquatic invertebrates. Objectives of this review are twofold: Firstly, an overview of protozoa in worldwide water was presented. Secondly, current knowledge of protozoa parasitism on aquatic invertebrates was detailed and the lack of data of their biological impact was pointed out.

Perinatal exposure to low doses of tributyltin chloride advances puberty and affects patterns of estrous cyclicity in female mice

Tributyltin (TBT), a proven endocrine-disrupting chemical, is well known to induce imposex in female gastropods. Herein we demonstrate the effects of low doses of tributyltin chloride (TBTCl) on the female offspring of KM mice. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. TBTCl dramatically advanced the age of onset of vaginal opening (VO) and first vaginal estrus, and reduced body weights at VO and first estrus. Furthermore, perinatal treatment with TBTCl significantly reduced the number of days between VO and first estrus. In addition, female offspring from dams exposed to 10 and 100 μg kg(-1) TBTCl exhibited altered patterns of estrous cyclicity in adulthood. In conclusion, perinatal exposure to low doses TBTCl result in early puberty and impaired estrous cyclicity in female mice, which suggest that TBTCl might act as an estrogen agonist or/and a disruptor on hypothalamic-pituitary function in the present study.

Vitellogenin-like protein measurement in caged Gammarus fossarum males as a biomarker of endocrine disruptor exposure: inconclusive experience

A vitellogenin (Vg) mass spectrometry-based assay was recently developed to actively biomonitor and assess the exposure of the amphipod Gammarus fossarum to endocrine-disrupting chemicals in freshwater hydrosystems. This paper focuses on the appropriate use of this biomarker, which requires good knowledge of its basal level in males and its natural variability related to intrinsic biotic and environmental abiotic factors. To obtain the lowest biomarker variability, we first studied some of these confounding factors. We observed that the spermatogenesis stage did not have an impact on the Vg level, allowing flexibility in the choice of transplanted gammarids. In the second part of the study, males were transplanted in two clean stations for 21 days, with results indicating a spatial and temporal variability of Vg levels. These Vg changes could not be correlated to environmental factors (e.g., temperature, pH and hardness of waters). Vg induction was then assessed in 21 stations having various levels of contamination. Inductions were observed for only two of the impacted stations studied. Under reference and contaminated conditions, a high interindividual variability of Vg levels was observed in caged organisms, severely limiting the sensitivity of the biomarker and its ability to detect a significant endocrine-disruptor effect. This may be explained by unidentified environmental factors that should later be determined to improved the use of Vg as a biomarker in male G. fossarum. Moreover, as discussed in this paper, recent advancements regarding the pleiotropic functions of the Vg gene in some species may complicate the application of this biomarker in males of invertebrate species.

Effects of perinatal exposure to low doses of tributyltin chloride on pregnancy outcome and postnatal development in mouse offspring

Tributyltin (TBT), an endocrine-disrupting chemical, is well known to induce imposex in female gastropods. In this study, we assessed the effects of low doses of tributyltin chloride (TBTCl) on dams and their offspring. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. There were no TBT treatment-related deaths or clinical signs of toxicity for dams, and no treatment-related effects on body weight, litter sizes, gestational length of dams, and sex ratio, lactational body weight, postnatal survival, age at eruption of incisors, and eye opening of pups. However, at 100 μg/kg, TBTCl retarded the testes descent of male offspring. Behavioral tests showed a significant delay in cliff-drop aversion response in offspring of 10 and 100 μg/kg groups, but no significant difference in the righting reflex between control and TBT-exposed offspring was detectable. These results indicate that neurobehavioral toxicity seems to be one sensitive indicator to assess the risk of low doses of TBT.

Vitellogenin-like proteins among invertebrate species diversity: potential of proteomic mass spectrometry for biomarker development

Cost-effective methodologies along with cross-species applicability constitute key points for biomarker development in ecotoxicology. With the advent of cheaper affordable genomic techniques and high throughput sequencing, omics tools could facilitate the assessment of effects of environmental contaminants for all taxa biodiversity. We assessed the potential of absolute quantification of proteins using mass spectrometry to develop vitellogenin (Vg)-like protein assays for invertebrates. We used available sequences in public databases to rapidly identify Vg-proteotypic peptides in seven species from different main taxa of protostome invertebrates (mollusk bivalves, crustacean amphipods, branchiopods, copepods and isopods, and insect diptera). Functional validation was performed by comparing proteomic signals from reproductive female tissue samples and negative controls (male or juvenile tissues). In a second part, we demonstrate in gammarids, daphnids, drosophilids, and gastropods that the assay validated in Vg-sequenced species can be applied to Vg-unsequenced species thanks to the evolutionary conservation of Vg-proteotypic peptide motifs. Finally, we discuss the relevance of mass spectrometry for biomarker development (specific measurement, rapid development, transferability across species). Our study supplies an illustration of the promising strategy to address the challenge of biodiversity in ecotoxicology, which consists in employing omics tools from comparative and evolutionary perspectives.