Organotins in a food web from the Three Gorges Reservoir, China: Trophic enrichment and potential health risk.

Triphenyltin (TPhT) and tributyltin (TBT) remain widely present in various aquatic environments despite restrictions on their use in many countries for many years. The biomagnification of these compounds in the aquatic food web remains controversial. This study reports the bioaccumulation of TPhT and TBT in aquatic animals in the Three Gorges Reservoir (TGR), a deep-water river channel-type reservoir and the largest reservoir in China.

Ignored microplastic sources from plastic bottle recycling.

The recovery and recycling of plastic products has increased dramatically in recent years as a strategy to achieve sustainable production and minimization of plastic pollution. However, the release of microplastics during plastic recycling has received little attention. We evaluated the generation and fate of microplastics in three typical facilities which make polyethylene terephthalate (PET) flakes using post-consumer PET bottles as raw material.

Thyroid-like hormone signaling in invertebrates and its potential role in initial screening of thyroid hormone system disrupting chemicals.

This review examines the presence and evolution of thyroid-like systems in selected aquatic invertebrates to determine the potential use of these organisms in screens for vertebrate thyroid hormone axis disrupting chemicals (THADCs). Such a screen might support the phasing out of some vertebrate testing. Although arthropods including crustaceans do not contain a functional thyroid signaling system, elements of such a system exist in the aquatic phyla mollusks, echinoderms, tunicates, and cephalochordates.

A proposed nomenclature for microplastic contaminants.

Microplastics are emerging contaminants with a wide environmental distribution and potential to elicit adverse impacts on organisms. Despite this lack of consistency among reports, data obtained from different investigations are often compared, resulting in the potential for misrepresentation of global microplastic contamination. Major interlaboratory variability in quantification of microplastic levels stem from size-related differences in sampling and analysis with different density solutions to separate microplastics.

A Crab Is Not a Fish: Unique Aspects of the Crustacean Endocrine System and Considerations for Endocrine Toxicology.

Crustaceans-and arthropods in general-exhibit many unique aspects to their physiology. These include the requirement to moult (ecdysis) in order to grow and reproduce, the ability to change color, and multiple strategies for sexual differentiation. Accordingly, the endocrine regulation of these processes involves hormones, receptors, and enzymes that differ from those utilized by vertebrates and other non-arthropod invertebrates.

Endocrine Disruption in Invertebrates: A Survey of Research Progress.

Manmade chemicals can interfere with endocrine processes and have permeated many ecosystems. Arguably, the most devastating example of endocrine disruption occurred in gastropod molluscs which led to the banning of tributyltin. The invertebrates consist of ∼95% of all known animals and possess endocrine systems that can significantly differ from that of vertebrates.

An effective method for evaluation of microplastic contaminant in gastropod from Taihu Lake, China.

Microplastics are ubiquitous in the environment. The isolation and characterization of microplastics can change, enabling science to elucidate the fate of microplastics in organisms. The main objective of the present study was to develop a rapid and effective method for the isolation, characterization, and quantification of microplastics from gastropod, and then evaluate the microplastic pollution in wild freshwater snails using the developed method.

Investigation of the microplastics profile in sludge from China's largest Water reclamation plant using a feasible isolation device.

Sewage sludge, which is widely applied to land as a fertilizer, is a key source of microplastics in the environment. We sought to develop a feasible device for isolation of microplastic from sewage sludge for further understanding their fates in the environment. In the present study, an effective isolation device, consisting of a fritted glass funnel and a glass filtration apparatus, was constructed to extract microplastics from sludge with nearly 100% recovery efficiency.

Involvement of glutamate and serotonin transmitter systems in male sex determination in Daphnia pulex.

Environmental sex determination occurs in many organisms, however the means by which environmental stimuli are translated into endocrine messages remains poorly understood. The N-methyl-ᴅ-aspartate receptor (NMDAR) was evaluated as a candidate neural sensor of environmental signals linking environmental cues to endocrine responses using the crustacean Daphnia pulex. NMDAR agonists, modulators, and antagonists were evaluated for their ability to impact D.

Phthalate Esters and Their Potential Risk in PET Bottled Water Stored under Common Conditions.

A great deal of attention has been paid lately to release of phthalate esters (PAEs) from polyethylene terephthalate (PET) bottles into PET bottled drinking water due to their potential endocrine-disrupting effects. Three kinds of PAEs, including diethyl phthalate (DEP), dimethyl phthalate (DMP) and dibutyl phthalate (DBP), were detected in 10 popular brands of PET bottles in Beijing, ranging from 101.97 μg/kg to 709.

The role of nuclear receptor E75 in regulating the molt cycle of Daphnia magna and consequences of its disruption.

Biological rhythms regulate innumerable physiological processes, yet little is known of factors that regulate many of these rhythms. Disruption in the timing of these rhythms can have devastating impacts on population sustainability. We hypothesized that the timing of the molt infradian rhythm in the crustacean Daphnia magna is regulated by the joint action of the protein E75 and nitric oxide.

Complementary roles of photoperiod and temperature in environmental sex determination in spp.

spp., a keystone genus in freshwater lentic habitats, are subject to environmental sex determination wherein environmental conditions dictate offspring sex and whether they reproduce asexually or sexually. The introduction of males into a population denotes the first step in the switch from asexual parthenogenetic reproduction to sexual reproduction.

Freshwater snail Parafossarulus striatulus estrogen receptor: Characteristics and expression profiles under lab and field exposure.

The modes of action by which putative endocrine disrupting chemicals (EDCs) elicit toxicity in mollusks remains unclear due to our limited understanding of the molluscan endocrine system. We identified and partially characterised the estrogen receptor (ER) of the mollusk Parafossarulus striatulus. The full-length cDNA of the ER of P.

Hemoglobin Levels Modulate Nitrite Toxicity to Daphnia magna.

Nitrogenous compounds enter the environment through various anthropogenic sources. Among these are nitrate (NO) and nitrite (NO) which can oxidize the heme moiety of hemoglobin and reduce the oxygen-carrying capacity of the molecule resulting in toxicity. Of the two anions, nitrite is more toxic.

No impacts of microcystins on wild freshwater snail Bellamya Aeruginosa fecundity from a eutrophic lake.

The preliminary investigation at shoreline along Taihu lake with different degrees of eutrophication status found no significant relationship between the microcystin-LR concentrations and the freshwater snail Bellamya aeruginosa fecundity or the abundance of wild freshwater snails. To further confirm the impact of eutrophication on the reproductive ability of snails, ecological mesocosm experiments were employed at four sites in Taihu lake during the algal blooming period, and no significant relationship was also found between MC-LR concentrations and snail fecundity. These results implied that eutrophication does not negatively or positive affect snail fecundity in Taihu Lake, a typical eutrophication lake in China.

Continuous Structured Population Models for Daphnia magna.

We continue our efforts in modeling Daphnia magna, a species of water flea, by proposing a continuously structured population model incorporating density-dependent and density-independent fecundity and mortality rates. We collected new individual-level data to parameterize the individual demographics relating food availability and individual daphnid growth. Our model is fit to experimental data using the generalized least-squares framework, and we use cross-validation and Akaike Information Criteria to select hyper-parameters.

Ligand-Mediated Receptor Assembly as an End Point for High-Throughput Chemical Toxicity Screening.

The high throughput screening of chemicals for interaction with intracellular targets is gaining prominence in the toxicity evaluation of environmental chemicals. We describe ligand-mediated receptor assembly as an early event in receptor signaling and its application to the screening of chemicals for interaction with targeted receptors. We utilized bioluminescence resonance energy transfer (BRET) to detect and quantify assembly of the methyl farnesoate receptor (MfR) in response to various high-production volume and other chemicals.

Preliminary evidence for snail deformation from a Eutrophic lake.

The incidence of deformities in snails Bellamya aeruginosa was investigated in a typical eutrophicated lake - Taihu Lake. A total of 15 105 specimens were collected, and 0.18-0.

Agonist-mediated assembly of the crustacean methyl farnesoate receptor.

The methyl farnesoate receptor (MfR) orchestrates aspects of reproduction and development such as male sex determination in branchiopod crustaceans. Phenotypic endpoints regulated by the receptor have been well-documented, but molecular interactions involved in receptor activation remain elusive. We hypothesized that the MfR subunits, methoprene-tolerant transcription factor (Met) and steroid receptor coactivator (SRC), would be expressed coincident with the timing of sex programming of developing oocytes by methyl farnesoate in daphnids.

Validation of a two-generational reproduction test in Daphnia magna: An interlaboratory exercise.

Effects observed within one generation disregard potential detrimental effects that may appear across generations. Previously we have developed a two generation Daphnia magna reproduction test using the OECD TG 211 protocol with a few amendments, including initiating the second generation with third brood neonates produced from first generation individuals. Here we showed the results of an inter-laboratory calibration exercise among 12 partners that aimed to test the robustness and consistency of a two generation Daphnia magna reproduction test.

Males on demand: the environmental-neuro-endocrine control of male sex determination in daphnids.

Branchiopod crustaceans (e.g., Daphnia sp.

Statistical validation of structured population models for Daphnia magna.

In this study we use statistical validation techniques to verify density-dependent mechanisms hypothesized for populations of Daphnia magna. We develop structured population models that exemplify specific mechanisms and use multi-scale experimental data in order to test their importance. We show that fecundity and survival rates are affected by both time-varying density-independent factors, such as age, and density-dependent factors, such as competition.

Estrogen alters the profile of the transcriptome in river snail Bellamya aeruginosa.

We evaluated the transcriptome dynamics of the freshwater river snail Bellamya aeruginosa exposed to 17β-estradiol (E2) using the Roche/454 GS-FLX platform. In total, 41,869 unigenes, with an average length of 586 bp, representing 36,181 contigs and 5,688 singlets were obtained. Among them, 18.

Endocrine regulation of predator-induced phenotypic plasticity.

Elucidating the developmental and genetic control of phenotypic plasticity remains a central agenda in evolutionary ecology. Here, we investigate the physiological regulation of phenotypic plasticity induced by another organism, specifically predator-induced phenotypic plasticity in the model ecological and evolutionary organism Daphnia pulex. Our research centres on using molecular tools to test among alternative mechanisms of developmental control tied to hormone titres, receptors and their timing in the life cycle.