Effects of 4-n-nonylphenol in liver of male and female viviparous fish (Poecilia vivipara)

4-n-Nonylphenol (NP) is one of the most toxic alkylphenols found in the environment. To evaluate the transcriptional effects of NP in the viviparous fish Poecilia vivipara, a hepatic transcriptome and qPCR analysis of genes were carried out. Guppies separated by sex were injected with two doses of NP (15 μg/g and 150 μg/g) or peanut oil (control). After 24 h, analysis of transcriptional level of Aryl Hydrocarbon Receptor (AhR), Estrogen Nuclear Receptor Alpha (ESR1), Pregnane X Receptor (PXR), Cytochromes P450 (CYP1A, CYP2K1 and CYP3A30), Glutathione S-transferase A3 and Mu 3 (GSTa3 and GSTMu3), SRY-Box Transcription Factor 9 (SOX9), Vitellogenin-1 (VIT), ATP Binding Cassette Subfamily C Member 1 (ABCC1), Multidrug Resistance-Associated Protein 2 (MRP2) and UDP Glucuronosyltransferase Family 1 Member A1 (UGT1A1) was evaluated. 205,046 transcripts were assembled and protein prediction resulted in 203,147 predicted peptides. In females, no significant changes were detected in the transcription of some phase I biotransformation and ABC transporter genes. AhR, PXR, GSTa3 and SOX9 genes where higher in the lower dose group (15 μg/g) compared to control. In male fish, no changes were observed in the transcript levels of the nuclear receptors, in endocrine disruption and phase I biotransformation genes. GSTa3 showed lower transcription in fish treated with both doses. ABCC1 was higher in guppies treated with the lower dose while MRP2 showed less transcripts. This short-term and low-dose exposure to NP caused changes that could serve as early indicators of deleterious processes. These results indicate P. vivipara as a good sentinel in biomonitoring programs.

Synthesis of Ce0.1La0.9MnO3 Perovskite for Degradation of Endocrine-Disrupting Chemicals under Visible Photons

The UN Environmental Protection Agency has recognized 4-n-Nonylphenol (NP) and bisphenol A (BPA) as among the most hazardous chemicals, and it is essential to minimize their concentrations in the wastewater stream. These industrial chemicals have been witnessed to cause endocrine disruption. This report describes the straightforward hydrothermal approach adopted to produce Ce0.1La0.9MnO3 (CLMO) perovskite’s structure. Several physiochemical characterization approaches were performed to understand the Ce0.1La0.9MnO3 (CLMO) perovskite crystalline phase, element composition, optical properties, microscopic topography, and molecular oxidation state. Here, applying visible photon irradiation, the photocatalytic capability of these CLMO nanostructures was evaluated for the elimination of NP and BPA contaminants. To optimize the reaction kinetics, the photodegradation of NP and BPA pollutants on CLMO, perovskite was studied as a specification of pH, catalyst dosage, and initial pollutant concentration. Correspondingly, 92% and 94% of NP and BPA pollutants are degraded over CLMO surfaces within 120 and 240 min, respectively. Since NP and BPA pollutants have apparent rate constants of 0.0226 min−1 and 0.0278 min−1, respectively, they can be satisfactorily fitted by pseudo-first-order kinetics. The decomposition of NP and BPA contaminants is further evidenced by performing FT-IR analysis. Owing to its outstanding photocatalytic execution and simplistic separation, these outcomes suggest that CLMO is an intriguing catalyst for the efficacious removal of NP and BPA toxicants from the aqueous phase. This is pertinent for the treatment of endocrine-disrupting substances in bioremediation.

In vitro screening for chemical inhibition of the iodide recycling enzyme, iodotyrosine deiodinase

The iodide recycling enzyme, iodotyrosine deiodinase (IYD), is a largely unstudied molecular mechanism through which environmental chemicals can potentially cause thyroid disruption. This highly conserved enzyme plays an essential role in maintaining adequate levels of free iodide for thyroid hormone synthesis. Thyroid disruption following in vivo IYD inhibition has been documented in mammalian and amphibian models; however, few chemicals have been tested for IYD inhibition in either in vivo or in vitro assays. Presented here are the development and application of a screening assay to assess susceptibility of IYD to chemical inhibition. With recombinant human IYD enzyme, a 96-well plate in vitro assay was developed and then used to screen over 1800 unique substances from the U.S. EPA ToxCast screening library. Through a tiered screening approach, 194 IYD inhibitors were identified (inhibited IYD enzyme activity by 20% or greater at target concentration of 200 μM). 154 chemicals were further tested in concentration-response (0.032-200 μM) to determine IC₅₀ and rank-order potency. This work broadens the coverage of thyroid-relevant molecular targets for chemical screening, provides the largest set of chemicals tested for IYD inhibition, and aids in prioritizing chemicals for targeted in vivo testing to evaluate thyroid-related adverse outcomes.

Disruptive effects of nonylphenol on reproductive hormones, antioxidant enzymes, and histology of liver, kidney and gonads in Caspian trout smolts

The endocrine-disrupting effect of pollutants such as alkylphenols has been considered a major concern during recent years. Although the effects of nonylphenol on the reproductive hormones of fish have been investigated in several studies, the effect of this endocrine disruptor on reproductive hormones of immature fish and salmonid smolts has been less addressed. The present work studied the effects of 1, 10 and 100 μg/l concentrations of nonylphenol on the levels of plasma reproductive hormones and liver antioxidant enzymes as well as on histopathology of reproductive and non-reproductive organs of male and female Caspian brown trout (Salmo trutta caspius) smolts after 21 days of exposure. The results of the present study showed that environmentally relevant concentrations of nonylphenol affected plasma levels of sex steroids; gonadotropins, phosphorus, estradiol to testosterone ratio, and also caused histopathological lesions in liver, kidney and testis tissues of immature Caspian brown trout during smolting. Nonylphenol significantly increased the levels of estradiol in plasma of both male and female smolts exposed to nonylphenol compared with the control groups. Exposure to nonylphenol decreased testosterone and FSH levels in both genders. It has also increased plasma levels of LH in females but did not affect LH levels in male fish. Liver SOD and CAT content was decreased in nonylphenol-exposed smolts. Therefore, the release of this economically valuable and endangered species into the rivers contaminated with nonylphenol should be avoided as it can have significant effects on the development and reproductive function of smolts.

Removal of Nonylphenol by using Fe-doped NaBiO3 compound as an efficient visible-light-heterogeneous Fenton-like catalyst

Fe-doped NaBiO₃ nanoscaled compounds were prepared by hydrothermal method and evaluated as a highly efficient photo-Fenton-like catalyst under visible light irradiation. The Fe-doped NaBiO₃ compound had a specific surface area of 41.42 m² g^-1, which is considerably larger than that of NaBiO₃ nanoparticles (28.81 m² g^-1). The compound exhibited an excellent visible light-Fenton-like catalysis activity, which is influenced by the iron content of the compound and the pH value of the solution. Under the optimal conditions, the Fe-doped NaBiO₃ compound led to fast degradation of Nonylphenol with an apparent rate constant of 5.71 × 10^-2 min^-1, which was 8.23-fold of that achieved by using NaBiO₃. The significantly enhanced visible light-Fenton-like catalytic property of the Fe-doped NaBiO₃ was attributed to the large surface area and the high adsorption capacity of the compound, and the Fenton catalytic ability of iron in the compound.

Joint effects of chronic exposure to environmentally relevant levels of nonylphenol and cadmium on the reproductive functions in male rockfish Sebastiscus marmoratus

Nonylphenol (NP) and Cadmium (Cd) are two common contaminants that can be detected in aquatic environments. Nevertheless, the combined toxicity of NP and Cd at environmentally relevant concentrations in aquatic organisms has not been thoroughly characterized to date. In the present study, the interactions between NP and Cd on male Sebastiscus marmoratus were studied. After 21 days of exposure, the brain aromatase activity was observed to be significantly induced by 100 ng/L NP and 40 μg/L Cd, whereas all of the concentrations of co-treatment resulted in an increase in brain aromatase activity. Additionally, NP could also reduce plasma testosterone concentration, while NP, Cd and their mixture could induce plasma 17β-estradiol (E2) concentration and VTG concentration. The interactions between NP and Cd on the reproductive physiology were antagonism. Our results also support the notion of using these indicators as biomarkers for exposure to EDCs and further extend the boundary of biomonitoring to environmental levels.

Relationship between biomarkers and endocrine-disrupting compounds in wild Girardnichthys viviparus from two lakes with different degrees of pollution

Despite great efforts worldwide to evaluate the effects of endocrine-disrupting compounds (EDCs) in fish, there is little information available about the interactions of EDCs with the disruption of the sexual endocrine axis in fish species with matrotrophic viviparity and intraluminal gestation. To understand these interactions, six sampling campaigns were performed within a period of 1 year in two lakes with different degrees of pollution. A battery of biomarkers of the oestrogenic response was assessed in the liver [vitellogenin, CYP 1A1, epoxide hydrolase activity, and metallothioneins (MT)] and MT in the head of Girardinichthys viviparus. Linear correlation analysis and canonical correspondence analysis were performed to explore the relationship between the oestrogenic response with EDCs and with metals. The biomarker responses were assessed using the water content of EDCs (oestrone, 17-β-oestradiol, oestriol, 17-α-ethinyl oestradiol, total phenols, bisphenol A, nonyl phenol, octyl phenol), as well as the PAHs indene[1,2,3-c,d]pyrene, naphthalene, pyrene, benzo[a]anthracene, benzo[k]fluoranthene and benzo[a]pyrene) and metals (Cu, Fe, Mn, Pb and Zn). Greater disruption of the sexual endocrine axis occurred in fish of both sexes inhabiting the polluted lake whose effects were apparently influenced by CYP 1A1 activity and by 17-α-ethinyl oestradiol. In addition, non-estrogenic mechanisms in the hypothalamus and pituitary glands in male fish were observed, elicited by endogenous levels and the water concentration of Pb. In contrast, in females from the less polluted lake, VTG induction was related to exogenous oestrogens. The disruption of the hypothalamic-pituitary-gonadal axis is a complex process influenced by both endogenous and exogenous factors and contributes to male feminisation by exposure to EDCs.

Developmental exposure of zebrafish (Danio rerio) to bisphenol-S impairs subsequent reproduction potential and hormonal balance in adults

In the recent years, there has been a growing concern about the production and use of bisphenol-A substitute, namely bisphenol-S (BPS). Due to its novel nature, there have been few studies addressing the ability of BPS to disrupt the endocrine system of animals. In the present study, zebrafish (Danio rerio) embryos were exposed to and reared in various concentrations of BPS (0, 0.1, 1, 10 and 100 μg/l) for 75 days. Then adult males and females were paired in spawning tanks for 7 days in clean water and the consequent effects on fish development, reproduction, plasma vitellogenin (VTG), sex steroids and thyroid hormone levels were investigated as endpoints. After 75 days of exposure, there was a skewed sex ratio in favor of females. The results also showed that body length and weight significantly decreased in males exposed to 100 μg/l of BPS. Gonadosomatic index was significantly reduced in fish at ≥ 10 μg/l. Hepatosomatic index exhibited a significant increase in both male and female fish. At ≥ 1 μg/l of BPS, plasma 17β-estradiol levels were significantly increased in both males and females. However, plasma testosterone showed a significant reduction in males exposed to 10 and 100 μg/l of BPS. A significant induction in plasma VTG level was observed in both males and females at ≥ 10 μg/l of BPS. Plasma thyroxine and triiodothyronine levels were significantly decreased at 10 and 100 μg/l of BPS in males, and at 100 μg/l in females. Egg production and sperm count were also significantly decreased in groups received 10 and 100 μg/l of BPS. Moreover, once time to hatching and hatching rates were calculated for fertilized eggs the postponed and decreased rates of hatching were observed. Taken together, these results suggest that developmental exposure to low concentrations of BPS has adverse effects on different parts of the endocrine system in zebrafish.