Exposure to bisphenol analogues interrupts growth, proliferation, and fatty acid compositions of protozoa Tetrahymena thermophila

Beta-cypermethrin-induced stress response and ABC transporter-mediated detoxification in Tetrahymena thermophila

β-Cypermethrin (β-CYP), a synthetic pyrethroid pesticide, is widely used for insect management. However, it also affects non-target organisms and pollutes aquatic ecosystems. Tetrahymena thermophila, a unicellular ciliated protist found in fresh water, is in direct contact with aquatic environments and sensitive to environmental changes. The proliferation of T. thermophila was inhibited and the cellular morphology changed under β-CYP stress. The intracellular ROS level significantly increased, and SOD activity gradually rose with increasing β-CYP concentrations. Under 25 mg/L β-CYP stress, 687 genes were up-regulated, primarily enriched in the organic cyclic compound binding and heterocyclic compound binding pathways. These include 8 ATP-binding cassette transporters (ABC) family genes, 2 cytochrome P450 monooxygenase genes, and 2 glutathione peroxidase related genes. Among of them, ABCG14 knockdown affected cellular proliferation under β-CYP stress. In contrast, overexpression of ABCG14 enhanced cellular tolerance to β-CYP. The results demonstrated that Tetrahymena tolerates high β-CYP concentration stress through various detoxification mechanisms, with ABCG14 playing a crucial role in detoxification of β-CYP.

Growth and reproductive toxicity of bisphenol A in Oikopleura dioica at environmentally relevant concentrations

Bisphenol A (BPA), a known endocrine disruptor, is ubiquitous in various aquatic environments. Appendicularians are among the most abundant mesozooplankton populations and occupy a crucial niche in marine ecosystems. However, no toxicological data are available concerning the effects of BPA on this functional group. In this study, an evaluation of the toxicity of environmentally relevant levels of BPA (2.5-150 μg/L) on the appendicularian Oikopleura dioica, including its morphology and transcriptome, was conducted. Our results demonstrated the high sensitivity of O. dioica to BPA, with a LC50 of 142 μg/L. Exposure to 125 μg/L BPA significantly inhibited the somatic growth, gonadal development and reproduction of individuals, whereas exposure to an environmentally safe concentration (2.5 μg/L) affected female fecundity and fitness as well as male gene expression. The results of the transcriptomic analysis suggest that males were more sensitive to BPA stress at the molecular level. BPA exposure not only led to abnormal secretion of digestive enzymes and phospholipase A2, affecting the function of the digestive system and arachidonic acid but also significantly down-regulated the expression of mRNAs related to enzymes involved in carbohydrate and energy metabolism in males. These findings suggest that the current safe environmental concentrations may not be safe.

Adverse outcomes of the newly emerging bisphenol A substitutes

BPA and its analogues are facing increasingly stringent regulations restricting their use due to the increasing knowledge of their harmful effects. It is therefore expected that novel BPA analogues and alternatives will replace them in plastic products, cans and thermal paper to circumvent restrictions imposed by legislation. This raises concerns about the safety of "BPA-free" products, as they contain BPA substitutes whose safety has not been sufficiently assessed prior to their market introduction. The regulatory agencies have recognised BPAP, BPBP, BPC2, BPE, BPFL, BPG, BPP, BPPH, BPS-MAE, BPS-MPE, BP-TMC, BPZ and the alternatives BTUM, D-90, UU and PF201 as compound with insufficient data regarding their safety. We demonstrate that the mentioned compounds are present in consumer products, food and the environment, thus exhibiting toxicological risk not only to humans, but also to other species where their toxic effects have already been described. Results of in silico, in vitro and in vivo studies examining the endocrine disruption and other effects of BPA analogues show that they disrupt the endocrine system by targeting various nuclear receptors, impairing reproductive function and causing toxic effects such as hepatotoxicity, altered behaviour and impaired reproductive function. In vitro and in vivo data on BPA alternatives are literally non-existent, although these compounds are already present in commonly used thermal papers. However, in silico studies predicted that they might cause adverse effects as well. The aim of this article is to comprehensively collate the information on selected BPA substitutes to illustrate their potential toxicity and identify safety gaps.

Assessment of potential environmental and human risks for Bisphenol AF contaminant

Bisphenol AF (BPAF) is found in high concentrations in aquatic environments due to the increased use of thermal paper and food packaging. However, there have been relatively few toxicological studies and potential risk assessments of BPAF. In this study, the risk quotient (RQ) and hazard quotient (HQ) of BPAF were derived to present the safety standards for environmental risk management and protection in lakes, rivers, bays, and Italian regions. We applied the species sensitivity distribution (SSD) method based on the previous ecotoxicological data and the results of supplementary toxicity tests on BPAF. From the SSD curves, the hazardous concentration for 5 % of the species (HC5) values for the acute and chronic toxicity data were 464.75 µg/L and 3.59 µg/L, respectively, and the acute- and chronic-based predicted no-effect concentration were derived as 154.92 µg/L and 1.20 µg/L, respectively. The acute-based RQ (RQA)values of BPAF in all regions were negligible (RQ < 0.1). The chronic-based RQ (RQC) in the Xitang River (XR) and the Central Italy (CI) showed a considerably high ecological risk (12.77 and 1.29) and the Hangzhou Bay (0.21), the South and North Italy (0.79 and 0.27), and the Tamagawa River (0.13) had a medium ecological risk (0.1 < RQ < 1.0). However, the HQ values based on the tolerable daily intake for BPAF over all age groups in these regions was < 0.1, indicating the low health risk. Nonetheless, the result of this study indicates that BPAF contamination is serious in XR and CI, and their use and emissions require continuous monitoring.

Fetal Origin of Abnormal Glucose Tolerance in Adult Offspring Induced by Maternal Bisphenol A Analogs Exposure

With the widespread use of bisphenol A (BPA) analogs, their health risks have attracted attention. The effects of maternal BPA analogs exposure on glucose homeostasis in adult offspring and the underlying fetal origins require further exploration. Herein, we exposed pregnant mice to two types of BPA analogs─BPB and BPAF; we evaluated glucose homeostasis in adult offspring and maternal-fetal glucose transport by testing intraperitoneal glucose tolerance, determining glucose and glycogen contents, conducting positron emission tomography (PET)/computed tomography (CT), detecting expression of placental nutrient transport factors, and assessing placental barrier status. We observed that adult female offspring maternally exposed to BPB and BPAF exhibited low fasting blood glucose in adulthood, with even abnormal glucose tolerance in the BPAF group. This phenomenon can be traced back to the elevated fetal glucose induced by the increased efficiency of placenta glucose transport in late pregnancy. On the other hand, the expression of genes associated with vascular development and glucose transport was significantly altered in the placenta in the BPAF group, potentially contributing to enhanced fetal glucose. These findings provide preliminary insights into potential mechanisms underlying the disturbance of glucose metabolism in adult female offspring mice induced by maternal exposure to BPA analogs.

Evaluation of the chronic toxicity of bisphenol A and bisphenol AF to sea cucumber Apostichopus japonicus after long-term single and combined exposure at environmental relevant concentration

Bisphenols are emerging endocrine disrupting pollutant, and several studies have reported that they are already ubiquitous in various environmental matrices and intend to deposit in sediment. The primary sources of bisphenols are river and sewage discharge. Sea cucumber (Apostichopus japonicus), a typical deposit feeder, is one of the most important commercial marine species in Aisa. However, the effects of the bisphenol A (BPA) and its analogues bisphenol AF (BPAF) on sea cucumber was unclear. In this study, we carried out field survey in major sea cucumber farming areas in northern China, with the aim of determining which bisphenol analogue is the major bisphenol contamination in this aquaculture area. The results showed that the presence of BPAF was detected in four sampling sites (Dalian, Tangshan, Laizhou, and Longpan). The mean level of BPAF in Laizhou sediment samples was the highest which reached to 9.007 ± 4.702 μ g/kg. Among the seawater samples, the BPAF only have been detected in the samples collected at Longpan. (0.011 ± 0.003 μ g/L). Furthermore, we conducted an experiment to evaluate the single and combined toxicity of BPA and BPAF on sea cucumbers. The concentrations were informed by the findings based on the results of field research. (0.1, 1.0, and 10 μ g/L). After exposure, the body weight gain, and specific growth rate showed no significant changes (P > 0.05). We observed the histological alterations in respiratory tree of treated sea cucumbers including the fusion and detachment of lining epithelial tissue, and increase of lumen space. However, the catalase (CAT), malondialdehyde (MDA), and glutathione (GSH) activity was not significantly changed (P > 0.05). We evaluated the effects of BPA and BPAF through calculating the integrated biomarker response index (IBR), and the results indicated that the toxicity of combined treatment was higher than single treatment. Additionally, BPAF exposure to A. japonicus was more toxic than BPA.

Effects of certain physical stresses on the composition of the membrane of bacteria implicated in food and environmental contamination

Bacterial membranes are implicated in the adaptation process of bacteria to numerous environmental conditions. In this context, our aim was to explain the consequences of a few physical stressor factors, like UV radiations and magnetic fields underlying the structural adaptation of cellular membranes to physical factors. The goal was also to review the state of the art about the link between membrane composition and bacterial resistance. According to comparative studies between ionizing γ-radiation, non-ionizing UVc radiations and Static Magnetic Field SMF, the response of some Gram negative bacteria appears to be generalized and was manifested by a membrane unsaturation, because of a production peak of unsaturated fatty acids. However, disturbances found inside the membrane, after UVB and Pulsed Electric Field (PEF) exposure were marked by a lower unsaturated fatty acids rate. This result is not concordant to disturbance seen after UVC treatment, even if the treatment is by UV radiation.

Probing the bioconcentration and metabolism disruption of bisphenol A and its analogues in adult female zebrafish from integrated AutoQSAR and metabolomics studies

Plenty of emerging bisphenol A (BPA) substitutes rise to wait for assessment of bioconcentration and metabolism disruption. Computational methods are useful to fill the data gap in chemical risk assessment, such as automated quantitative structure-activity relationship (AutoQSAR). It is not clear how AutoQSAR performs in predicting the bioconcentration factor (BCF) in adult zebrafish. Herein, AutoQSAR was used to predict the logBCFs of BPA, bisphenol AF (BPAF), bisphenol B, bisphenol F and bisphenol S (BPS). For the test set, a linear relationship was shown between the observed and predicted logBCFs with a slope of 0.97. The predicted logBCFs of these five bisphenols were quite close to their experimental data with a slope of 0.94, suggesting better performance than directed message passing neural networks and EPI Suite with a slope of 0.69 and 0.61, respectively. Thus, AutoQSAR is powerful in modeling logBCFs in fish with minimal time and expertise. To link bioconcentration with metabolic effects, female zebrafish were exposed to BPA, BPAF and BPS for metabolomics analysis. BPA caused a significant disturbance in amino acid metabolism, while BPAF and BPS significantly altered another three metabolic pathways, showing chemical-specific responses. BPAF with the highest logBCF elicited the strongest metabolomic responses reflected by the metabolic effect level index, followed by BPA and BPS. Thus, BPAF and BPS elicited higher or similar metabolism disruption compared with BPA in female zebrafish, respectively, reflecting consequences of bioconcentration.

Can BPA Analogs Affect Cellular and Biochemical Responses in the Microalga Phaeodactylum tricornutum Bohlin?

Bisphenol A analogs (BPA analogs) are emerging contaminants with a rising production caused by the replacement of BPA with these compounds. The increased production of BPA analogs is leading to their increased release into various ecosystems, including marine ones. The aim of this study was to evaluate the biological effects of BPA analogs on a primary producer, the diatom Phaeodactylum tricornutum Bohlin. Three different BPA analogs (BPAF, BPF, and BPS) and their mixture were tested at the environmental relevant concentration of 300 ng/L. Growth, cell size and several biomarkers of oxidative stress and oxidative damage were measured. Our results indicated that the tested compounds caused a reduced growth rate and induced oxidative stress, altering many antioxidant enzymes in P. tricornutum. However, no oxidative damages were observed.

Removal of endocrine disruptor compounds, CO2 fixation, and macromolecules accumulation in Thermosynechococcus sp. CL-1 cultivation

Recently, concern on several environmental issues including the pollutant discharge and high concentration of CO2 have gained high interest due to its impact on ecosystem and global warming effect, respectively. Implementation of photosynthetic microorganism carries out numerous advantages including high efficiency of CO2 fixation, the great endurance under extreme conditions and generation of valuable bioproducts. Thermosynechococcus sp. CL-1 (TCL-1), a cyanobacterium, has the ability to perform CO2 fixation and accumulation of various byproducts under extreme conditions like high temperature and alkalinity, presence of estrogen, or even using swine wastewater. This study aimed to assess TCL-1 performance under various endocrine disruptor compounds (bisphenol-A, 17-β-estradiol/E2, and 17-α-ethynilestradiol/EE2), concentrations (0-10 mg/L), light intensities (500-2000 µE/m2/s), and dissolved inorganic carbon/DIC levels (0-113.2 mM). Addition of E2 content even until 10 mg/L carried out insignificant biomass growth interruption along with the improvement in CO2 fixation rate (79.8 ± 0.1 mg/L/h). Besides the influence of E2, application of higher DIC level and light intensity also enhanced the CO2 fixation rate and biomass growth. The highest biodegradation of E2 at 71% was achieved by TCL-1 in the end of 12 h cultivation period. TCL-1 dominantly produced protein (46.7% ± 0.2%), however, production of lipid and carbohydrate (39.5 ± 1.5 and 23.3 ± 0.9%, respectively) also could be considered as the potential source for biofuel production. Thus, this study can provide an efficient strategy in simultaneously dealing with environmental issues with side advantage in production of macromolecules.

BPA and its alternatives BPF and BPAF exaggerate hepatic lipid metabolism disorders in male mice fed a high fat diet

Alternatives to Bisphenol A (BPA), such as BPF and BPAF, have found increasing industrial applications. However, toxicological research on these BPA analogues remains limited. This study aimed to investigate the effects of BPA, BPF, and BPAF exposure on hepatotoxicity in mice fed with high-fat diets (HFD). Male mice were exposed to the bisphenols at a dose of 0.05 mg per kg body weight per day (mg/kg bw/day) for eight consecutive weeks, or 5 mg/kg bw/day for the first week followed by 0.05 mg/kg bw/day for seven weeks under HFD. The low dose (0.05 mg/kg bw/day) was corresponding to the tolerable daily intake (TDI) of BPA and the high dose (5 mg/kg bw/day) was corresponding to its no observed adverse effect level (NOAEL). Biochemical analysis revealed that exposure to these bisphenols resulted in liver damage. Metabolomics analysis showed disturbances of fatty acid and lipid metabolism in bisphenol-exposed mouse livers. BPF and BPAF exposure reduced lipid accumulation in HFD mouse liver by lowering glyceride and cholesterol levels. Transcriptomics analysis demonstrated that expression levels of genes related to fatty acid synthesis and metabolism were changed, which might be related to the activation of the PPAR signaling pathway. Besides, a feedback regulation mechanism might exist to maintain hepatic metabolic homeostasis. For the first time, this study demonstrated the effects of BPF and BPAF exposure in HFD-mouse liver. Considering the reality of the high prevalence of obesity nowadays and the ubiquitous environmental distribution of bisphenols, this study provides insight and highlights the adverse effects of BPA alternatives, further contributing to the consideration of the safe use of such compounds.

Congener-Specific Uptake and Metabolism of Bisphenols in Carrot Cells: Dissipation Kinetics, Biotransformation, and Enzyme Responses

Food consumption has been considered a key pathway of bisphenol compound (BP) exposure for humans. However, there is a lack of evidence concerning their congener-specific behavior and metabolism in plants. Herein, we examined the uptake and metabolism of five BPs in plants using carrot cells. Bisphenol S (BPS) and bisphenol AF (BPAF) exhibited substantially lower dissipation rates in the cells than the other BPs, indicating a strong selectivity in the uptake and metabolism among bisphenol congeners. For a total of 23 metabolites of BPs, the predominant biotransformation pathways were found to be glycosylation, methoxylation, and conjugation, while hydroxylation, methylation, and glutathionylation were only observed for some BPs. The changes in the mRNA expression of cytochrome P450 (P450) and the activities of glycosyltransferase and glutathione S-transferase were remarkably higher in cells exposed to bisphenol F, bisphenol A, and bisphenol B than in cells exposed to BPS and BPAF, indicating congener specificity in their effects on enzymes and the associated biotransformation processes. Consequently, the potential congener-specific differences in plant uptake, metabolism, and accumulation must be considered when assessing the environmental risks posed by these commonly used plasticizers.

Metabolic alteration of Tetrahymena thermophila exposed to CdSe/ZnS quantum dots to respond to oxidative stress and lipid damage

CdSe/ZnS Quantum dots (QDs) are possibly released to surface water due to their extensive application. Based on their high reactivity, even small amounts of toxicant QDs will disturb water microbes and pose a risk to aquatic ecology. Here, we evaluated CdSe/ZnS QDs toxicity to Tetrahymena thermophila (T. thermophila), a model organism of the aquatic environment, and performed metabolomics experiments. Before the omics experiment was conducted, QDs were found to induce inhibition of cell proliferation, and reactive oxygen species (ROS) production along with Propidium iodide labeled cell membrane damage indicated oxidative stress stimulation. In addition, mitochondrial ultrastructure alteration of T. thermophila was also confirmed by Transmission Electron Microscope results after 48 h of exposure to QDs. Further results of metabolomics detection showed that 0.1 μg/mL QDs could disturb cell physiological and metabolic metabolism characterized by 18 significant metabolite changes, of which twelve metabolites improved and three decreased significantly compared to the control. Kyoto Encyclopedia of Genes and Genomes analysis showed that these metabolites were involved in the ATP-binding cassette transporter and purine metabolism pathways, both of which respond to ROS-induced cell membrane damage. In addition, purine metabolism weakness might also reflect mitochondrial dysfunction associated with energy metabolism and transport abnormalities. This research provides deep insight into the potential risks of quantum dots in aquatic ecosystems.

Drivers of owning more BPA

Bisphenol A (BPA) is a ubiquitous environmental toxin worldwide. Despite the many studies documenting the toxicity of this substance, it remains a popular choice for consumer products. The internet, magazine articles, and newspaper reports are replete with tips on how to avoid BPA exposure, which mostly spread contradictory and often unscientific information. Therefore, based on a comprehensive search of the available biomedical literature, we summarized several confounding factors that may be directly or indirectly related to human BPA exposure. We found that the unique properties of BPA materials (i.e. low cost, light-weight, resistance to corrosion, and water/air-tightness), lack of personal health and hygiene education, fear of BPA-substitutes (with yet unknown risks), inappropriate production, processing, and marketing of materials containing BPA, as well as the state of regulatory guidance are influencing the increased exposure to BPA. Besides, we detailed the disparities between scientifically derived safe dosages of BPA and those designated as "safe" by government regulatory agencies. Therefore, in addition to providing a current assessment of the states of academic research, government policies, and consumer behaviors, we make several reasonable and actionable recommendations for limiting human exposure to BPA through improved labeling, science-based dosage limits, and public awareness campaigns.

Bacteria compete with hematite nanoparticles during their uptake by the ciliate Tetrahymena thermophila

Bacterial accumulation of engineered nanoparticles (NPs) result in their transfer along the food chain. However, there are a lot of NPs not associated with bacteria. Whether bacteria, as representative biotic particles, influence the biological uptake of these non-associated NPs in aquatic ecosystems is unclear. In the present study, we examined the effects of four bacterial species on the uptake kinetics of polyacrylate-coated hematite nanoparticles (HemNPs) by the ciliate Tetrahymena thermophila. The HemNPs were well dispersed. Their adsorption on the bacteria was low with negligible uptake by T. thermophila through bacterial ingestion. This result demonstrated the feasibility of examining the effects of bacteria on the uptake of non-associated HemNPs. Our study further showed that all four bacterial species inhibited the uptake of HemNPs by T. thermophila; however, the effects of the bacterial cells on the physiological activities of the ciliate with respect to its uptake of HemNPs were negligible. In the absence of phagocytosis by T. thermophila, none of the bacteria inhibited HemNP uptake. This observation suggested that bacterial cells competed with the HemNPs for uptake via phagocytosis. Therefore, in evaluations of the environmental risks of NPs, their competition with biotic particles should be taken into account.

Exposure to phthalates DEHP and DINP May lead to oxidative damage and lipidomic disruptions in mouse kidney

Di(2-ethylhexyl) phthalate (DEHP) has been well acknowledged for its endocrine disruption and associated metabolic diseases, leading to the search for safer industrial alternatives including di-isononyl phthalate (DINP). However, safety data for the latter chemical has been relatively scarce particularly regarding potential damage to the kidney at low doses. Five-week-old ICR male mice were exposed to vehicle, DEHP or DINP (0.05 and 4.8 mg/kg bw) daily via gavage for 5 weeks. We observed increased levels of reactive oxygen species and malondialdehyde, decreased levels of reduced glutathione, in the kidney at higher dose for both chemicals suggestive of oxidative damage. Elevated levels of inflammatory cytokines tumor necrosis factor-α and interleukin-6 of the kidney further suggested inflammatory status as a result of phthalate exposure in both high dose groups. Targeted lipidomics demonstrated greatest changes in the kidney induced by high dose of DEHP, although DINP also induced significant changes in phospholipids diacylglycerides that are associated with lipid accumulation in glomerular podocytes and inflammatory responses. Our data suggest that oxidative stress may be involved in both DEHP- and DINP-induced renal lipidomic disruption and continue to question the suitability of DINP as proper DEHP substitute.

Lipidomic Changes in Banana (Musa cavendish) during Ripening and Comparison of Extraction by Folch and Bligh-Dyer Methods

Banana (Musa cavendish) is one of the most popular fruits globally and is an important foodstuff in many regions, attributed to its high nutritional value. Contrast to its high consumption volume, relatively little research has been conducted on banana lipidome. In this study, two classic lipid extraction methods, Folch and Bligh-Dyer, were compared for studying the banana lipidome in both the peel and pulp by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lipidomic profiles were also investigated to understand the changes of lipid molecules during three ripening stages (unripe, ripe, and overripe), and differences in lipids from different origins were also compared. This study suggested that although both Folch and Bligh-Dyer methods allow lipidome investigation, the latter demonstrated advantage in rendering higher extraction efficiency for the majority of lipid molecules in banana samples, particularly in the pulp. In peel, there were differences in the trends of each lipid classes at various stages of maturity, while the majority of lipid classes in pulp reached the highest levels with reduced desaturation at ripe stage, consistent with previous studies. Moreover, the lipidomic profiles of bananas in different habitats differed significantly according to partial least-squares discriminant analysis. This study for the first time provided comprehensive atlas of lipidomic changes of Musa cavendish during maturity and in different origins. These findings will facilitate better understanding of biochemical changes in banana and offer new tools for food chemical analyses in the understanding of mechanisms underlying lipid metabolism.