An integrated transcriptome-microbiome host relationship associated with paraben toxicity in the brackish water flea Diaphanosoma celebensis

Parabens, a group of alkyl esters of p-hydroxybenzoic acid, have been found in aquatic systems in particular, leading to concerns about their potential impact on ecosystems. This study investigated the effects of three commonly used parabens, methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP), on the brackish water flea Diaphanosoma celebensis. The results showed that PrP had the most adverse impact on survival rates, followed by EtP and MeP, while MeP and EtP induced significant adverse effects on reproductive performance. A transcriptome analysis revealed significant differential gene expression patterns in response to paraben exposure, with MeP associated with the most significant effects. MeP and EtP exposure produced greater disruption in the microbiota of D. celebensis than did PrP compared with control groups, and we identified eight key microbiota, including Ruegeria and Roseovarius. Correlation analysis between transcriptome and microbiome data revealed key interactions between specific microbiota and host gene expression. Certain microbial taxa were associated with specific genes (e.g. cuticle related genes) and toxicological pathways, shedding light on the complex molecular response and in vivo toxicity effects of parabens. These findings contribute to a deeper understanding of the molecular mechanisms underlying paraben toxicity and highlight the importance of considering the ecological impact of chemical contaminants in aquatic ecosystems.

Simultaneous determination of dehydroacetic acid, benzoic acid, sorbic acid, methylparaben and ethylparaben in foods by high-performance liquid chromatography

In this study, an analytical method was established and validated to determine the preservatives such as dehydroacetic acid, benzoic acid, sorbic acid, methylparaben and ethylparaben. The level of preservatives was measured by solvent extraction method adding purification process with carrez reagent and by high-performance liquid chromatography (HPLC). The developed analytical method was successfully applied to determine the concentration of preservatives in various food samples including jam, cheese and soy sauce, displaying high accuracy (recoveries between 87.8% and 110%) and precision (%RSD less than 5.92% and 7.72% for intra-day and inter-day, respectively). To verify the applicability of the improved test method, selected 13 food items and collected 521 samples were monitored. As a result, all the cases met the Korea standard guidelines. Consequently, this study is expected to contribute to the safety management of preservatives for domestic distribution and imported food.

Molecular mechanism of ethylparaben on zebrafish embryo cardiotoxicity based on transcriptome analyses

Ethylparaben (EP), one of the parabens, a ubiquitous food and cosmetic preservatives, has caused widespread concern due to its health risks. Recently, studies have found that parabens exposure during pregnancy is negatively correlated with fetal and early childhood development. However, studies about EP on embryo development are few. In this study, the cardiotoxicity effects of EP concentrations ranging from 0 to 20 mg/L on zebrafish embryo development were explored. Results showed that EP exposure induce abnormal cardiac function and morphology, mainly manifested as pericardial effusion and abnormal heart rate in early-stage development of zebrafish embryos. Through transcriptome sequencing followed by Gene Ontology enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, we further confirmed that EP exposure ultimately leads to cardiac morphologic abnormalities via the following three mechanisms: 1. Disruption of the retinoic acid signaling pathway related to original cardiac catheter development; 2. Inhibition of gene expression related to myocardial contraction; 3. Orientation development disturbance of heart tube. Moreover, O-Dianisidine staining, whole-mount in situ hybridization at 30 and 48 hours post fertilization (hpf) and hematoxylin-eosin staining results all confirmed the decreased heart's return blood volume, misoriented heart tubes toward either the right or the middle side, and heart loop defects. For the first time, we explored the mechanism by which EP exposure causes abnormal heart development in zebrafish embryos, laying the foundation for further revealing of the EP toxicity on embryonic development.

Species sensitivity distributions for ethylparaben to derive protective concentrations for soil ecosystems

Ethylparaben is used as an antifungal preservative. Although some countries have implemented regulations for human exposure to parabens, environmental regulations for ethylparaben have not been established. This study provides new toxicological data for ethylparaben, for which data regarding soil organisms were previously lacking. Although ethylparaben toxicity has been reported in other species, we present herein the first comprehensive study of its toxicity in soil organisms. We used 12 test species (Lycopersicon esculentum, Vigna radiata, Hordeum vulgare, Oryza sativa, Eisenia andrei, Folsomia candida, Lobella sokamensis, Caenorhabiditis elegans, Chlamydomonas reinhardtii, Chlorococcum infusionum, Chlorella sorokiniana, Chlorella vulgaris) from eight taxonomic groups for acute bioassays and nine test species (L. esculentum, V. radiata, H. vulgare, O. sativa, C. reinhardtii, C. infusionum, C. sorokiniana, and C. vulgaris) from five taxonomic groups for chronic bioassays. A suite of acute and chronic toxicity tests, using 21 soil species, was conducted to estimate EC₅₀ values, which facilitated the construction of species sensitivity distributions (SSDs) and the calculation of protective concentrations (PCs). Acute and chronic PC₉₅ values (protective concentration for 95% of species) for ethylparaben were estimated to be 14 and 5 mg/kg dry soil, respectively. To the best of our knowledge, this is the first study to evaluate the toxicity of ethylparaben to soil species and derive PCs for soil ecosystems based on SSDs. Therefore, the data presented in this study can be used as a basis for further investigations of paraben toxicity to the soil environment.

The effects of ethylparaben and propylparaben on the development and fecundity of Drosophila melanogaster

Parabens are widely used as preservatives in pharmaceuticals, cosmetics, and food products. Ethylparaben (EP) and propylparaben (PP) are particularly preferred because of their bactericidal and fungicidal effects. Although generally described as safe compounds, many studies have reported that parabens have estrogenic and endocrine-disrupting properties. In the present study, the effects of EP and PP (50 mM, 100 mM and 200 mM) on Drosophila melanogaster development and fecundity were investigated. No differences were found in the pupation and maturation percentages in all concentrations of parabens (p > 0.05). However, it was found that the mean pupation and maturation times increased in all treatment groups (p < 0.05). A statistically significant decrease (p < 0.05) in the number of offspring of the 200 mM ethylparaben exposure group was observed. In all paraben groups, a significant reduction in mean fecundity was found compared to the control group (p < 0.05).

Residual behaviors and metabolic pathway of ethylparaben in Drosophila melanogaster

OBJECTIVE

Parabens are commonly used as preservatives in foodstuffs, cosmetics, and pharmaceutical products. The widespread use of parabens has led to their leaking into the environment. Concerns about the safety of parabens have recently increased due to their potential endocrine-disrupting effects as an emerging contaminant. Thus, it is necessary to study the metabolism of parabens in vivo.

METHODS

In this study, Drosophila melanogaster in males and females were exposed to ethylparaben (EP) concentration group (300 mg/L, 700 mg/L, and 1000 mg/L), and control group (0 mg/L) by the capillary feeding assay (CAFE). We quantified the activity of the detoxification-related carboxylesterase (CarE). The contents of EP metabolites in D. melanogaster, including p-hydroxybenzoic acid (PHBA), methylparaben (MP), and intact EP were carried out by high-performance liquid chromatography (HPLC). The regression model between EP metabolites (PHBA and MP) and CarE was developed using the Fourier series fitting method.

RESULTS

The general level of EP metabolites (PHBA, MP, and intact EP) accumulation was accounted for 5.6-11.5% in D. melanogaster. As EP accumulated, the activity of CarE increased, and the activity of CarE in females was higher than males, which is inconsistent with the result of EP intake dose. Additionally, there were significant differences in the proportion of EP metabolites between female and male flies, and the results of sex comparison were different depending on the EP treated groups and EP metabolites. In general, PHBA of EP hydrolytic product and MP of EP transesterification product in D. melanogaster were 41.4-63.9% and 10.4-24.6%, respectively. In terms of the rest of the EP existed in intact form and ranged from 22.4% to 34.0%. Moreover, the EP metabolites in the conjugated form were higher than those in the free form. The regression model between EP metabolites and CarE was established, showing that the CarE activity can be used to estimate the content of PHBA and MP.

CONCLUSION

The result indicates that the EP can accumulate in the body through food. Hydrolysis is the main metabolic pathway of EP in D. melanogaster, and transesterification is another metabolic pathway of EP. Additionally, the EP metabolites in flies mainly exist in conjugated form. Furthermore, the Fourier series fitting method model between EP metabolites and CarE, providing theoretical support to study the dose-effect relationship between metabolites of parabens and CarE. This study not only provides a mathematical basis for the safety evaluation of parabens, but also provides support for the further study of the toxicological effects of parabens.

Effect of ethylparaben on the growth and development of Drosophila melanogaster on preadult

Parabens are esters of p-hydroxybenzoic acid, including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and the like. This substance has estrogenic and antiandrogenic effects, and a putative role in promoting cancer through endocrine disruption. By exposing Drosophila melanogaster to different concentrations of EP (300 mg/L, 700 mg/L, and 1000 mg/L), we investigated the effect of EP on the growth and development of D. melanogaster before emergence. We found that EP prolonged the development cycle of D. melanogaster, and changed the relative expression levels of Met, Gce, EcR, Kr-h1, and Br. In addition, EP reduced the titer of juvenile hormone Ⅲ (JH Ⅲ) and 20-hydroxyecdysone (20E), and delayed the peak of hormone secretion. This study provided a more objective and thorough assessment of safety for the parabens.

Ethylparaben induces apoptotic cell death in human placenta BeWo cells via the Caspase-3 pathway

Parabens are generally used as preservatives in foods, pharmaceuticals, and various other commercial products. Among them, ethylparaben has weaker estrogenic characteristics than endogenous estrogen. However, growing evidence indicates that ethylparaben has an adverse effect on various human tissues. Here, we investigated whether ethylparaben induces cell death by affecting cell viability, cell proliferation, cell cycle, and apoptosis using the human placenta cell line BeWo. Ethylparaben significantly decreased cell viability in a dose-dependent manner. It caused cell cycle arrest at sub-G1 by reducing the expression of cyclin D1, whereas it decreased the cell proportion at the G0/G1 and S phases. Furthermore, we verified that ethylparaben induces apoptotic cell death by enhancing the activity of Caspase-3. Taken together, our results suggest that ethylparaben exerts cytotoxic effects in human placental BeWo cells via cell cycle arrest and apoptotic pathways.

Parabens in breast milk and possible sources of exposure among lactating women in Korea

Parabens, broad-spectrum antimicrobial preservatives widely used in various consumer products and food, are suspected to be linked with several adverse health effects in humans, especially newborn babies, infants, and young children. While human exposure to parabens has been frequently reported by measuring the concentration of parabens in urine, similar measurements in breast milk have rarely been made. To determine paraben concentrations in breast milk and possible sources of exposure, four major parabens, including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) were measured in breast milk samples collected from 260 lactating women in South Korea. Demographic, socioeconomic, and behavioral factors associated with the presence of parabens in breast milk were determined. EP concentrations were detected at the highest levels in breast milk samples, followed by MP, PP, and BP. Pre-pregnancy BMI, parity, use of basic skin care products, use of cosmetics, canned beverage, and type of milk consumption were associated with higher frequencies of paraben detection. In addition, type of milk, parity, and drinking status were significantly associated with the concentration of EP. Multiple regression analyses showed that colostrum and transitional milk samples had higher levels of EP than mature milk samples. The estimated daily intake of parabens in infants via breastfeeding appears to be negligible when compared to the acceptable daily intake values set forth by the European Food Safety Authority (EFSA); however, considering the vulnerability of breastfed infants and ubiquitous sources of exposure from daily use of household and personal toiletries, efforts to identify sources and mitigate exposure are warranted.

Heat-activated persulfate oxidation of methyl- and ethyl-parabens: Effect, kinetics, and mechanism

We evaluated the degradation of methylparaben (MeP) and ethylparaben (EtP), two representative parabens, using the heat-activated persulfate system in a laboratory. Both sulfate and hydroxyl radicals contributed to the removal of the two parabens. The degradations of both MeP and EtP were improved by increasing the heating temperature or persulfate dose in accordance with a pseudo-first-order reaction model. The oxidation efficiency of parabens was found to be pH-dependent; decreasing in the order pH 5.0 > 7.0 > 9.0. The presence of chloride, bicarbonate, or humic acid was found to inhibit the degradation of the two parabens to some extent because of competition for the reactive radicals, with humic acid having the most serious effect. Dealkylation of the methyl unit, decarboxylation of the carboxylic group, and subsequent hydrolysis are proposed to be involved in the degradation pathway of MeP. The results suggest that the heat-activated persulfate system might be efficiently applied in the treatment of paraben-containing water samples. This was also supported by the results of applying this system to treat a real water sample containing both MeP and EtP.

Identification of ethylparaben as the antimicrobial substance produced by Brevibacillus brevis FJAT-0809-GLX

In this study, crude antimicrobial extract from the culture supernatant of Brevibacillus brevis FJAT-0809-GLX was extracted, and its antimicrobial activity was investigated with the agar diffusion method. The results showed that the antimicrobial activity of the culture supernatant of B. brevis FJAT-0809-GLX increased with the extension of the incubation time of B. brevis FJAT-0809-GLX. The antimicrobial spectrum assays showed that this crude antimicrobial extract from culture supernatant of B. brevis FJAT-0809-GLX could inhibit the growth of both bacteria and fungi. A heat stability test was performed, and different temperatures (30°C, 50°C and 70°C) did not affect the antibiotic activity of this crude antimicrobial extract. The crude antimicrobial extract was also tolerable to changes in pH levels. Its antibiotic activity against Escherichia coli was stable at pH 1 to pH 11, with zone sizes ranging from 18.46mm to 22.19mm. Almost all of the crude extracts extracted using different solvents showed variable degrees of inhibition zones against E. coli, with zone sizes ranging from 17.29mm to 19.62mm, except petroleum ether and butanol extracts, which were found to be completely inactive. Purification of the antimicrobial components was carried out using a column chromatographic technique with column chromatography grade silica gel and analyzed by an Agilent 7890A Network GC system. The separated compound was identified as ethylparaben, with a retention time of 21.980min and a relative amount of 95.50%. The antimicrobial activity of ethylparaben on different types of bacteria and fungi was investigated, and ethylparaben was shown to inhibit different types of microbes to different extents. To the best of our knowledge, this is the first report demonstrating that the bacterium B. brevis could produce ethylparaben.

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.