In vitro evaluation of cytotoxic and genotoxic effects of Di(2-ethylhexyl)-phthalate (DEHP) on European sea bass (Dicentrarchus labrax) embryonic cell line

Di(2-ethylexyl) phthalate and chromosomal damage: Insight on aneugenicity from the cytochalasin-block micronucleus assay

Bis(2-ethylhexyl) phthalate is the most abundant phthalate used as plasticizer to soften plastics and polymers included in medical devices. Human and environmental exposure may occur because DEHP is not chemically bound to plastics and can easily leach out of the materials. This phthalate is classified as reproductive toxicant and possible carcinogen to humans. The genotoxic potential has still to be clarified, but there are indications suggesting that DEHP may have aneugenic effects. To further investigate DEHP genotoxicity, the cytochalasin-block micronucleus assay was applied and combined with the CREST staining to characterise micronucleus content and gain insights on its genotoxic mode of action. Chromosomal damage was also analysed in metaphase and ana-telophase cells and the morphology of the mitotic spindle was investigated to evaluate the possible involvement of this cellular apparatus as a target of DEHP. Our findings indicated that DEHP induced a statistically significant increase in the frequency of micronuclei as well as in the frequency of CREST-positive micronuclei. Consistently, disturbance of chromosome segregation and induction of numerical chromosome changes were observed together with changes in spindle morphology, formation of multipolar spindles and alteration of the microtubule network. Experiments performed without metabolic activation demonstrated a direct action of DEHP on chromosome segregation not mediated by its metabolites. In conclusion, there is consistent evidence for an aneugenic activity of DEHP. A thresholded genotoxic activity was identified for DEHP, disclosing possible implications for risk assessment.

High concentrations of phthalates affect the early development of the sea urchin Paracentrotus lividus

The toxicity of three phthalates (PAEs) - butylbenzyl phthalate (BBP), diethyl phthalate (DEP), and di-(2-ethylhexyl) phthalate (DEHP) - was tested on the Mediterranean sea urchin Paracentrotus lividus. Fertilized eggs were exposed to environmental and high PAE concentrations for 72 h. The potential toxic effects on larval development and any morphological anomalies were then assessed to estimate PAEs impact. Environmental concentrations never affected development, while high concentrations induced toxic effects in larvae exposed to BBP (EC50: 2.9 ×103 µg/L) and DEHP (EC50: 3.72 ×103 µg/L). High concentrations caused skeletal anomalies, with a slight to moderate impact for DEP/DEHP and BBP, respectively. PAE toxicity was: BBP>DEHP>DEP. In conclusion, the three PAEs at environmental concentrations do not pose a risk to sea urchins. However, PAE concentrations should be further monitored in order not to constitute a concern to marine species, especially at their early developmental stages.

Phthalates contamination in sediments: A review of sources, influencing factors, benthic toxicity, and removal strategies

Sediments provide habitat and food for benthos, and phthalates (PAEs) have been detected in numerous river and marine sediments as a widely used plastic additive. PAEs in sediments is not only toxic to benthos, but also poses a threat to pelagic fish and human health through the food chain, so it is essential to comprehensively assess the contamination of sediments with PAEs. This paper presents a critical evaluation of PAEs in sediments, which is embodied in the analysis of the sources of PAEs in sediments from multiple perspectives. Biological production is indispensable, while artificial synthesis is the most dominant, thus the focus was on analyzing the industrial and commercial sources of synthetic PAEs. In addition, since the content of PAEs in sediments varies, some factors affecting the content of PAEs in sediments are summarized, such as the properties of PAEs, the properties of plastics, and environmental factors (sediments properties and hydrodynamic conditions). As endocrine disruptors, PAEs can produce toxicity to its direct contacts. Therefore, the effects of PAEs on benthos immunity, endocrinology, reproduction, development, and metabolism were comprehensively analyzed. In addition, we found that reciprocal inhibition and activation of the systems lead to genotoxicity and apoptosis. Finally, the paper discusses the feasible measures to control PAEs in wastewater and leachate from the perspective of source control, and summarizes the in-situ treatment measures for PAEs contamination in sediments. This paper provides a comprehensive review of PAEs contamination in sediments, toxic effects and removal strategies, and provides an important reference for reducing the contamination and toxicity of PAEs to benthos.

Comparative toxicity of beach mesoplastics from South Spain: An in vitro approach

Plastics, particularly mesoplastics, dominate beach debris and act as carriers of hazardous chemicals, either initially present in plastics or absorbed from the surrounding environment. In this study, mesoplastics were collected from five beaches in the southern region of Spain to investigate their potential impact on marine life. In vitro assays employing fish liver cells (PLHC-1) were conducted to evaluate the toxicity of methanolic extracts derived from intact mesoplastics and after simulated photodegradation. LC-MS analysis of the methanolic extracts revealed the presence of organophosphate esters, phthalates, and phthalate alternatives. The extracts from photodegraded plastics generally showed higher cytotoxicity, ability to generate reactive oxygen species (ROS), and genotoxicity (micronuclei formation) than those from intact mesoplastics. All the extracts induced EROD activity in PLHC-1 cells, indicating the presence of significant amounts of CYP1A inducers in beach mesoplastics. Thus, mesoplastics contain chemicals able to induce cytotoxicity and genotoxicity in PLHC-1 cells, and further photodegradation of mesoplastics facilitates the release of additional chemicals, increasing the overall toxicity. This work also highlights the usefulness of cell-based assays to better define the risks of plastic pollution.

Di (2-ethylhexyl) phthalate alters neurobehavioral responses and oxidative status, architecture, and GFAP and BDNF signaling in juvenile rat's brain: Protective role of Coenzyme10

Di-(2-ethylhexyl) phthalate (DEHP), a phthalate plasticizer, is widely spread in the environment, presenting hazards to human health and food safety. Hence, this study examined the probable preventive role of coenzyme10 (CQ10) (10 mg/kg.b.wt) against DEHP (500 mg/kg.wt) - induced neurotoxic and neurobehavioral impacts in juvenile (34 ± 1.01g and 3 weeks old) male Sprague Dawley rats in 35-days oral dosing trial. The results indicated that CQ10 significantly protected against DEHP-induced memory impairment, anxiety, depression, spatial learning disorders, and repetitive/stereotypic-like behavior. Besides, the DEHP-induced depletion in dopamine and gamma amino butyric acid levels was significantly restored by CQ10. Moreover, CQ10 significantly protected against the exhaustion of CAT, GPx, SOD, GSH, and GSH/GSSG ratio, as well as the increase in malondialdehyde, Caspas-3, interleukin-6, and tumor necrosis factor-alpha brain content accompanying with DEHP exposure. Furthermore, CQ10 significantly protected the brain from the DEHP-induced neurodegenerative alterations. Also, the increased immunoexpression of brain-derived neurotrophic factor, not glial fibrillary acidic protein, in the cerebral, hippocampal, and cerebellar brain tissues due to DEHP exposure was alleviated with CQ10. This study's findings provide conclusive evidence that CQ10 has the potential to be used as an efficient natural protective agent against the neurobehavioral and neurotoxic consequences of DEHP.

Emerging and legacy plasticisers in coastal and estuarine environments: A review

The occurrence of plastic waste in the environment is an emerging and ongoing concern. In addition to the physical impacts of macroplastics and microplastics on organisms, the chemical effects of plastic additives such as plasticisers have also received increasing attention. Research concerning plasticiser pollution in estuaries and coastal environments has been a particular focus, as these environments are the primary entry point for anthropogenic contaminants into the wider marine environment. Additionally, the conditions in estuarine environments favour the sedimentation of suspended particulate matter, with which plasticisers are strongly associated. Hence, estuary systems may be where some of the highest concentrations of these pollutants are seen in freshwater and marine environments. Recent studies have confirmed emerging plasticisers and phthalates as pollutants in estuaries, with the relative abundance of these compounds controlled primarily by patterns of use, source intensity, and fate. Plasticiser profiles are typically dominated by mid-high molecular weight compounds such as DnBP, DiBP, and DEHP. Plasticisers may be taken up by estuarine and marine organisms, and some phthalates can cause negative impacts in marine organisms, although further research is required to assess the impacts of emerging plasticisers. This review provides an overview of the processes controlling the release and partitioning of emerging and legacy plasticisers in aqueous environments, in addition to the sources of plasticisers in estuarine and coastal environments. This is followed by a quantitative analysis and discussion of literature concerning the (co-)occurrence and concentrations of emerging plasticisers and phthalates in these environments. We end this review with a discussion the fate (degradation and uptake by biota) of these compounds, in addition to identification of knowledge gaps and recommendations for future research.

Comparative toxicity of conventional versus compostable plastic consumer products: An in-vitro assessment

This study investigates the toxicity of methanolic extracts obtained from compostable plastics (BPs) and conventional plastics (both virgin and recycled). Additionally, it explores the potential influence of plastic photodegradation and composting on toxic responses using a battery of in vitro assays conducted in PLHC-1 cells. The extracts of BPs, but not those of conventional plastics, induced a significant decrease in cell viability (<70%) in PLHC-1 cells after 24 h of exposure. Toxicity was enhanced by either photodegradation or composting of BPs. Extracts of conventional plastics, and particularly those of recycled plastics, induced 7-ethoxyresorufin-O-deethylase (EROD) activity and micronucleus formation in exposed cells, indicating the presence of significant amounts of CYP1A inducers and genotoxic compounds in the extracts, which was enhanced by photodegradation. These findings highlight the importance of investigating the effects of degradation mechanisms such as sunlight and composting on the toxicity of BPs. It is also crucial to investigate the composition of newly developed formulations for BPs, as they may be more harmful than conventional ones.

Combined cytotoxicity of phthalate esters on HepG2 cells: A comprehensive analysis of transcriptomics and metabolomics

Phthalate esters (PAEs), widely used as plasticizers, may pose a potential environmental and human hazard. The aim of this study was to compare the cytotoxicity of di(2-ethylhexyl) phthalates (DEHP) and dibutyl phthalate (DBP)) after their exposure to HepG2 cells alone or in combination. HepG2 cells treated with individual/combined DEHP and DBP at a dose of 10-2 M for 24 h were selected for metabolome and transcriptome analysis. The results demonstrated that exposure to the mixtures of DEHP and DBP caused enhanced or reduced toxic effects regarding 8 pathways with 1065 downregulated genes and 643 upregulated genes, in comparison with those of single chemicals. The combined toxicity of mixture revealed both synergistic and antagonistic interactions between DEHP and DBP. Besides, combined exposure to DEHP and DBP promoted TCA cycle, pyrimidine, and purine metabolism, while an antagonistic effect on fatty acid derangement should require further investigation. To summarize, our results suggest that DEHP exposed alone or combined with DBP caused a variety of metabolic disorders, and the type of combination effects varied among metabolic pathways.

DEHP exposure impairs human skeletal muscle cell proliferation in primary culture conditions: preliminary study

The plasticizer di (2-ethylhexyl) phthalate (DEHP) inhibits differentiation, impairs glucose metabolism, and decreases mitochondrial function in murine muscle satellite cells; however, if these effects are translated to human cells is unknown. The goal of this study was to evaluate changes in morphology and proliferation of primary human skeletal muscle cells exposed to DEHP. Rectus abdominis muscle samples were obtained from healthy women undergoing programed cesarean surgery. Skeletal muscle cells were isolated and grown under standard primary culture conditions, generating two independent sample groups of 25 subcultures each. Cells from the first group were exposed to 1 mM DEHP for 13 days and monitored for changes in cell morphology, satellite cell frequency and total cell abundance, while the second group remained untreated (control). Differences between treated and untreated groups were compared using generalized linear mixed models (GLMM). Cell membrane and nuclear envelope boundary alterations, loss of cell volume and presence of stress bodies were observed in DEHP-treated cultures. DEHP-treated cultures also showed a significant reduction in satellite cell frequency compared to controls. Exposure to DEHP reduced human skeletal muscle cell abundance. Statistical differences were found between the GLMM slopes, suggesting that exposure to DEHP reduced growth rate. These results suggest that exposure to DEHP inhibits human skeletal muscle cell proliferation, as evidenced by reduced cell abundance, potentially compromising long-term culture viability. Therefore, DEHP induces human skeletal muscle cell deterioration potentially inducing an inhibitory effect of myogenesis by depleting satellite cells.

Graphical abstract

Di(2-ethylhexyl) phthalate and microplastics cause necroptosis and apoptosis in hepatocytes of mice by inducing oxidative stress

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer and an endocrine disruptor. Microplastics (MPs) are pathogenic small plastic particles and abundant in the aqueous environment. The problem of residual hazards of plastic products is worthy of study, especially the joint exposure of a variety of plastic-related products to the toxic effect. We used 200 mg/kg DEHP and 10 mg/L MPs to establish exposure model in vivo and 2 mM DEHP and 200 μg/L MPs to establish AML12 cell exposure model in vitro. In vivo study results showed that compared with the control group (NC) group, DEHP and MPs significantly increased the contents of malondialdehyde and hydrogen peroxide, and significantly decreased the contents of glutathione and the activity of superoxide dismutase, total antioxidant capacity, catalase and glutathione peroxidase. The level of oxidative stress was further aggravated after combined exposure. The reactive oxygen species level of AML12 exposed to DEHP and MPs in vitro was significantly higher than NC group, and the combined exposure was significantly higher than the single exposure. The in vivo and in vitro also confirmed that DEHP and MPs could significantly increase the mRNA and protein levels of apoptosis markers and necroptosis markers and there was an additive effect. After N-acetylcysteine treatment in vitro, the above-mentioned oxidative stress level and cell damage decreased significantly. This study provided a reference for advocating the reduction of the mixed use of plastic products, and provided a basis for preventing the harm of plastic products residues.

Water-Soluble Polymer Polyethylene Glycol: Effect on the Bioluminescent Reaction of the Marine Coelenterate Obelia and Coelenteramide-Containing Fluorescent Protein

The current paper considers the effects of a water-soluble polymer (polyethylene glycol (PEG)) on the bioluminescent reaction of the photoprotein obelin from the marine coelenterate Obelia longissima and the product of this bioluminescent reaction: a coelenteramide-containing fluorescent protein (CCFP). We varied PEG concentrations (0–1.44 mg/mL) and molecular weights (1000, 8000, and 35,000 a.u.). The presence of PEG significantly increased the bioluminescent intensity of obelin but decreased the photoluminescence intensity of CCFP; the effects did not depend on the PEG concentration or the molecular weight. The photoluminescence spectra of CCFP did not change, while the bioluminescence spectra changed in the course of the bioluminescent reaction. The changes can be explained by different rigidity of the media in the polymer solutions affecting the stability of the photoprotein complex and the efficiency of the proton transfer in the bioluminescent reaction. The results predict and explain the change in the luminescence intensity and color of the marine coelenterates in the presence of water-soluble polymers. The CCFP appeared to be a proper tool for the toxicity monitoring of water-soluble polymers (e.g., PEGs).

Short-Term Exposure to MPs and DEHP Disrupted Gill Functions in Marine Bivalves

The synergistic impact of microplastics (MPs) and organic pollutants remains poorly understood in the marine environment. This study aimed to assess the toxicity of polypropylene microplastics (PS) and/or di-(2-ethylhexyl) phthalate (DEHP) on marine clams. Both Ruditapes philippinarum and Tegillarca granosa were exposed to PS and DEHP individually and combined at environmentally relevant concentrations for 48 h. The filtration rate, antioxidant enzymes activity, lipid peroxidation, reactive oxygen species accumulation, and histological alterations were evaluated. Our results show that single or co-exposure to MPs and DEHP significantly decreases the filtration rate in both type of clams, but the latter exhibited stronger inhibition effect. Close examination of accumulation of reactive oxygen species and related biomarkers revealed that combined exposure exerts greater oxidative stress in the cells, which causes more serious histopathological damage in the gills of the bivalves. Our study implies that MPs, in synergy with organic pollutants, can be more harmful for marine organisms.

Acute toxicity of bioplastic leachates to Paracentrotus lividus sea urchin larvae

In an attempt to ensure that bioplastics, progressively replacing petrochemical-derived plastics, do not release any harmful compound to the environment, the study assessed the toxic effects of three innovative bioplastic products: polyhydroxybutyrate resin (PHB), polylactic acid cups (PLA) and a polylactic acid/polyhydroxyalkanoate 3D printing filament (PLA/PHA), together with a synthetic polyvinyl chloride (PVC) toy in Paracentrotus lividus sea urchin larvae. PVC toy was the most toxic material, likely due to the added plasticizers; remarkably, even if PHB is conceived as a nontoxic polymer, it showed a slight toxicity and Gas Chromatography-Mass Spectometry analysis (GC-MS) revealed the presence of a wide range of additives. Conversely, PLA cups and PLA/PHA filament were innocuous for the larvae, a positive outcome for these renewable solutions. Proven that additives are also used in some bioplastic formulations, they should be carefully addressed to ensure that they are as safe as regarded.

Genotoxic activity of endocrine disrupting compounds commonly present in paper mill effluents

In the present study we evaluated cytotoxic and genotoxic activities of endocrine disrupting compounds (EDCs), including dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), and nonylphenol (NP), which have been previously identified in effluents from two paper mills with different paper production technologies (virgin or recycled fibres). Moreover, we evaluated genotoxic activity of the effluents from these two paper mills and compared it to the activity of artificial complex mixtures consisting of the seven EDCs at concentrations detected in corresponding paper mill effluents. None of the EDCs was genotoxic in Salmonella typhimurium (SOS/umuC assay), while all induced DNA damage in human hepatocellular carcinoma (HepG2) cells (comet assay). After 4 h of exposure genotoxic effects were determined at concentrations ≥ 1 μg/L for BBP and DEHP, ≥10 μg/L for DMP, DEP, DBP, and BPA, and ≥100 μg/L for NP, while after 24 h of exposure DNA damage occurred at ≥10 μg/L for DBP, BPA and NP, and ≥100 μg/L for DMP, DEP, BBP and DEHP. The effluents and corresponding artificial mixtures of EDCs from paper mill that uses virgin fibres did not induce DNA damage in HepG2 cells, while the effluents and corresponding artificial mixtures for the paper mill that uses recycled fibres were genotoxic. Genotoxic activity of effluents was significantly higher compared to corresponding artificial mixtures suggesting the presence of further unknown compounds contributing to the effect. Wastewater monitoring based on chemical analysis is limited to determination of targeted compounds and does not take into account possible interactions between chemicals in mixtures. Therefore, it alone cannot provide an adequate information on potential toxic effects required for the assessment of genotoxic activity of real environmental samples and their potential threats to the environment and human health.

Hazards of phthalates (PAEs) exposure: A review of aquatic animal toxicology studies

Phthalates (PAEs) are of wide concern because they are commonly used in various plastic products as plasticizers, and can found their way into the environment. However, their interaction with the environment and their toxicity in aquatic animals is still a matter of intense debate. In this review on PAEs in aquatic environments (lakes, rivers and seas), it is found that there is a large variety and abundance of PAEs in developing countries, and the total concentration of PAEs even exceeds 200 μg / L. The interaction between metabolic processes involved in the toxicity induced by various PAEs is summarized for the first time in the article. Exposure of PAEs can lead to activation of the detoxification system CYP450 and endocrine system receptors of aquatic animals, which in turn causes oxidative stress, metabolic disorders, endocrine disorders, and immunosuppression. Meanwhile, each system can activate / inhibit each other, causing genotoxicity and cell apoptosis, resulting in the growth and development of organisms being blocked. The mixed PAEs shows no cumulative toxicity changes to aquatic animals. For the combined pollution of other chemicals and PAEs, PAE can act as an agonist or antagonist, leading to combined toxicity in different directions. Phthalate monoesters (MPEs), the metabolites of PAEs, are also toxic to aquatic animals, however, the toxicity is weaker than the corresponding parent compounds. This review summarizes and analyzes the current ecotoxicological effects of PAEs on aquatic animals, and provides guidance for future research.

Establishment and characterisation of single cell-derived embryonic stem cell lines from the gilthead seabream, Sparus aurata

An important bottleneck in fish aquaculture research is the supply and maintenance of embryos, larvae, juvenile and adult specimens. In this context, cell lines represent alternative experimental models for in vitro studies that complement in vivo assays. This allows us to perform easier experimental design and sampling and avoid the sacrifice of animals. Embryonic stem (ES) cell lines have attracted increasing attention because they have the capability to proliferate indefinitely and could be differentiated into any cell type of the organism. To minimise cell heterogeneity and increase uniformity of in vitro studies results, in this manuscript we report the development and characterisation of two single cell-derived ES cell lines (monoclonal) from the morula stage embryos of the gilthead seabream, Sparus aurata, named as SAEC-A3 and SAEC-H7. Both cell lines have been passaged for over 100 times, indicating the establishment of long-term, immortalised ES cell cultures. Sequence analyses confirmed the seabream origin of the cell lines, and growth analyses evidenced their high viability and proliferating activity, particularly in culture medium supplemented with 10-15% fetal bovine serum and 22 °C. Both cell lines showed the ability to generate embryoid bodies and show different sensitivity and response to all-trans retinoic acid. The analysis of epithelial (col1α1) and neuronal (sox3) markers in differentiated cultures revealed that SAEC-A3 tended to differentiate towards epithelial-like cells whereas SAEC-H7 tended to differentiate towards neuronal-like cells. Both cell lines were efficiently transfected with pDsRed2-ER and/or pEGFP-N1 plasmids, indicating that they could represent useful biotechnological tools. Daily expression of pcna showed significant expression rhythms, with maximum levels of cell proliferation during the day-night transition. Currently, these cell lines are being successfully used as experimental models for the study of cellular metabolism, physiology and rhythms as well as for toxicological, pharmacological and gene expression analyses.

Combined cytotoxicity of polystyrene nanoplastics and phthalate esters on human lung epithelial A549 cells and its mechanism

Awareness of risks posed by widespread presence of nanoplastics (NPs) and bioavailability and potential to interact with organic pollutants has been increasing. Inhalation is one of the more important pathways of exposure of humans to NPs. In this study, combined toxicity of concentrations of polystyrene NPs and various phthalate esters (PAEs), some of the most common plasticizers, including dibutyl phthalate (DBP) and di-(2-ethyl hexyl) phthalate (DEHP) on human lung epithelial A549 cells were investigated. When co-exposed, 20 μg NPs/mL increased viabilities of cells exposed to either DBP or DEHP and the modulation of toxic potency of DEHP was greater than that of DBP, while the 200 μg NPs/mL resulted in lesser viability of cells. PAEs sorbed to NPs decreased free phase concentrations (C_free) of PAEs, which resulted in a corresponding lesser bioavailability and joint toxicity at the lesser concentration of NPs. The opposite effect was observed at the greater concentration of NPs, which may result from the dominated role of NPs in the combined toxicity. Furthermore, our data showed that oxidative stress and inflammatory reactions were mechanisms for combined cytotoxicities of PAEs and NPs on A549 cells. Results of this study emphasized the combined toxic effects and mechanisms on human lung cells, which are helpful for assessing the risk of the co-exposure of NPs and organic contaminants in humans.

Emerging Roles of PETase and MHETase in the Biodegradation of Plastic Wastes

Polyethylene terephthalate (PET) is extensively used in plastic products, and its accumulation in the environment has become a global concern. Being a non-degradable pollutant, a tremendous quantity of PET-bearing plastic materials have already accumulated in the environment, posing severe challenges towards the existence of various endangered species and consequently threatening the ecosystem and biodiversity. While conventional recycling and remediation methodologies so far have been ineffective in formulating a "green" degradation protocol, the bioremediation strategies-though nascent-are exhibiting greater promises towards achieving the target. Very recently, a novel bacterial strain called Ideonella sakaiensis 201-F6 has been discovered that produces a couple of unique enzymes, polyethylene terephthalate hydrolase and mono(2-hydroxyethyl) terephthalic acid hydrolase, enabling the bacteria to utilize PET as their sole carbon source. With a detailed understanding of the protein structure of these enzymes, possibilities for their optimization as PET degrading agents have started to emerge. In both proteins, several amino acids have been identified that are not only instrumental for catalysis but also provide avenues for the applications of genetic engineering strategies to improve the catalytic efficiencies of the enzymes. In this review, we focused on such unique structural features of these two enzymes and discussed their potential as molecular tools that can essentially become instrumental towards the development of sustainable bioremediation strategies. Degradation PET by wild type and genetically engineered PETase and MHETase. Effect of the MHETase-PETase chimeric protein and PETase expressed on the surface of yeast cells on PET degradation is also shown.

In vitro evaluation of cytotoxic effects of di (2-ethylhexyl) phthalate (DEHP) produced by Bacillus velezensis strain RP137 isolated from Persian Gulf

Phthalates are widely used in polymer science and have potential toxicity related to their chemical structures. However, lots of evidence indicate that phthalate derivatives are undoubtedly produced as secondary metabolites by organisms, including plants, animals, and microorganisms. In the present study, Bacillus velezensis strain RP137 was cultured under optimized conditions. Its biomass was extracted with ethyl acetate with one fraction showing cytotoxic properties. A pure compound was isolated from the active fraction using combined silica gel and LH20 size exclusion column chromatography. Structural evaluation including FT-IR, ¹H NMR, ¹³C NMR, HR-MS and CHN analysis identified the purified compound as di(2-ethylhexyl)phthalate (DEHP) with the formula C₂₄H₃₈O₄ and the molecular weight of 389.29 Da. The microorganism-derived (stereospecific) DEHP was strongly reduced the proliferation and induced cytotoxic effects on various eukaryotic cell lines in compare to the synthetic racemic mixture of the compound when assessed by MTT assay. Furthermore, crystal violet assay and morphological changes confirmed the cytotoxic effect of DEHP. Interestingly, non-malignant SV40-immortalized fibroblast cells were less affected by the purified DEHP. Further evaluation on the antibacterial activity of DEHP documented no effect toward Gram-positive (S. aureus) and Gram-negative (E. coli and P. aeruginosa) pathogens even at a high concentration of 100 μM. In conclusion, existence of DEHP as byproduct of microorganism's metabolism can seriously be considered as a warning to human health.

Effects of plastic particles on germination and growth of soybean (Glycine max): A pot experiment under field condition

Plastic residues have become a serious environmental problem in areas where agricultural plastic film are used intensively. Although numerous of studies have been done to assess its impacts on soil quality and crop yields, the understanding of meso-plastic particles effects on plant is still limited. In this study, low density polyethylene (PE) and biodegradable plastic (Bio) mulch film were selected to study the effects of meso-plastic debris on soybean germination and plant growth with the accumulation levels of 0%, 0.1%, 0.5% and 1% in soil (w: w, size ranging 0.5-2 cm) by a pot experiment under field condition. Results showed that the germination viability of soybean seeds was reduced to 82.39%, 39.44% and 26.06% in the treatments with 0.1%, 0.5% and 1% added plastic debris compared to the control (CK), respectively, suggesting that plastic residues in soil inhibit the viability of soybean seed germination. The plastic debris had a significant negative effect on plant height and culm diameter during the entire growth stage of soybean. Similarly, the leaf area at harvest was reduced by 1.97%, 6.86% and 11.53% compared to the CK in the treatments with 0.1%, 0.5% and 1% plastic debris addition, respectively. In addition, the total plant biomass under plastic addition was reduced in both the flowering and harvesting stages, compared to the CK. For the different type of plastic residues, plant height, leaf area and root/shoot ratio at group PE were significantly lower than those of groups treated by Bio. In conclusion, PE debris had a greater negative effects on plant height, culm diameter, leaf area and root/shoot ratio while Bio debris mainly showed the adverse effects on germination viability and root biomass especially at the flowering stage. Therefore, further research is required to elaborate plastic particles' effects on different stages of crops and soil quality.

Effects of fast food packaging plasticizers and their metabolites on steroid hormone synthesis in H295R cells

The health risks of exposure to plasticizers have received widespread attention, however, little is known about the effects of fast food packaging plasticizers on steroid hormone synthesis. In the present study, the types and migration of plasticizers in some commonly used fast-food packaging materials were detected by GC-MS, and the interference effects of these plasticizers and their metabolites on steroid hormone synthesis in the human body were evaluated by the H295R steroidogenesis assay. The GC-MS results showed that the main plasticizer compounds that migrated from fast food packaging into food were di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and bis(2-ethylhexyl) adipate (DEHA). Exposure to these chemicals (100-1000 μM) can significantly reduce the viability of H295R cells in a dose-response manner, and these plasticizers and their metabolites that migrated into oily foods at high temperatures (0.25-25 μM) could significantly increase the E2 level and reduce the T level in H295R cells. According to the qRT-PCR data, 0.25 to 25 μM mono(2-ethylhexyl) phthalate (MEHP) significantly upregulated the expression levels of 17β-HSD1 and CYP19A1, and downregulated those of CYP17A1, CYP11A1 and StAR. The Western blot results were consistent with those of qRT-PCR. In summary, these results indicated that even exposure to low concentrations (≤1 mg/l or 2.5 μM) of these chemicals and their metabolites can cause significant endocrine-disrupting effects.

Di-(2-ethylhexyl) phthalate induced nephrotoxicity in quail (Coturnix japonica) by triggering nuclear xenobiotic receptors and modulating the cytochrome P450 system

Di-(2-ethylhexyl) phthalate (DEHP), a plasticizer that is mainly used in the production of polyvinyl alcohol-containing chloride products, has attracted attention due to potential threats to human health and the environment. Nevertheless, knowledge of DEHP-induced nephrotoxicity is still limited. To explore the mechanism of DEHP-induced nephrotoxicity, quail were treated with 0, 250, 500 and 1000 mg/kg DEHP by oral gavage for 45 days. Based on the results of histopathological analysis, DEHP exposure induced a disorganized renal structure, a partially dilated glomerulus and an atrophied Bowman's space. Renal tubular epithelial cells were unclear, and swelling of columnar epithelial cells was observed, suggesting that DEHP exposure caused renal disease and renal injury. Notably, DEHP interfered with the homeostasis of cytochrome P450 systems (CYP450s) by increasing the activities or contents of CYP450s (total CYP450, Cyt b5, ERND, APND, AH and NCR). The expression levels of certain CYP450 isoforms (CYP1A, CYP1B, CYP2C, CYP2D, CYP2J and CYP3A) were significantly downregulated in the kidney in DEHP-treated quail. Furthermore, DEHP induced the expression of nuclear receptors (AHR, CAR and PXR) in a dose-dependent manner. The results of this study suggested that DEHP-induced nephrotoxicity in quail was associated with the induction of nuclear xenobiotic receptor (NXR) responses and interference with CYP450 homeostasis. In conclusion, all data indicated that DEHP induced nephrotoxicity by triggering NXRs and modulating the cytochrome P450 system. The results of this study provide a new basis for understanding the nephrotoxicity of DEHP.

Effect of DEHP on SCFA Production by Anaerobic Fermentation of Waste Activated Sludge

Diethylhexyl phthalate (DEHP) is a common plasticizer in industrial production. Recently, environmental problems caused by microplastics have drawn wide attention. As the microplastics have a large specific surface area, the release rate of the plasticizer from the microplastics to the environment is accelerated. The DEHP in the wastewater enters the wastewater treatment plants (WWTPs) along with the urban pipeline. After DEHP enters the WWTPs, it may affect the anaerobic fermentation with waste activated sludge (WAS) as raw material. So far, there has been no study on the effect of DEHP on anaerobic fermentation of WAS. Our study focused on the impact of exogenous DEHP on WAS anaerobic fermentation, and the results showed that DEHP mainly affects the solubilization stage of sludge anaerobic digestion, but has no significant effect on other stages. It does not affect the total yield and composition of short-chain fatty acids (SCFA). However, DEHP inhibited the solubilization process of WAS anaerobic fermentation, which was mainly manifested by the changes of soluble protein and soluble polysaccharide in the system. The results of the analysis of microbial communities revealed that the addition of DEHP did not change the diversity of microbial communities, but caused a change in the abundance of microbial organisms. DEHP reduced the abundance of acetogen bacteria and increased the abundance of methanogens. This work provides some insights into WAS fermentation systems in the presence of DEHP and helps to gain a better understanding of the potential environmental hazards of microplastics.