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Pesticide contamination to water bodies is considered as a global concern. This study involves the use of activated carbon synthesized from the shells of Thevetia peruviana shell (TPS) for the removal of the potential pollutant, Methoxychlor (MXC) from water. The TPS was activated using potassium hydroxide and was characterized by pH point zero charge (pHpzc), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET). The activated material shows a high BET of 394.97 m2/g with a pHpzc of 2. Batch experiments were conducted to investigate the influence of operating conditions such as pH, temperature, adsorbent dosage, initial concentration, and contact time. Under optimum conditions, adsorption of MXC onto TPS had a removal efficiency of 94.90%. The sorption experiment data best fits the pseudo-second-order (PSO) kinetic model (R2 = 0.999) and also correlated with Langmuir isotherm model (maximum sorption capacity of 197.2 mg/g). The results reveal that TPS can be considered as an excellent adsorbent material for the removal of pesticides and applicable for real waste water treatment. [ABSTRACT FROM AUTHOR]

Laccase immobilized and cross-linked on Fe3S4/earthworm-like mesoporous SiO2 (Fe3S4/EW-mSiO2) was used to degrade methoxychlor (MXC) in aqueous environments. The effects of various parameters on the degradation of MXC were determined using free and immobilized laccase. Immobilization improved the thermal stability and reuse of laccase significantly. Under the conditions of pH 4.5, temperature 40 °C, and reaction time 8 h, the degradation rate of MXC by immobilized laccase reached a maximum value of 40.99% and remained at 1/3 of the original after six cycles. The excellent degradation performance of Fe3S4/EW-mSiO2 was attributable to the pyrite (FeS2) impurity in Fe3S4, which could act as an electron donor in reductive dehalogenation. Sulfide groups and Fe2+ reduced the activation energy of the system resulting in pyrite-assisted degradation of MXC. The degradation mechanism of MXC in aqueous environments by laccase immobilized on Fe3S4/EW-mSiO2 was determined via mass spectroscopy of the degradation products. This study is a new attempt to use pyrite to support immobilized laccase degradation. [ABSTRACT FROM AUTHOR]

Efficient detection of selected persistent organic pollutants (POPs) is extremely important for the safety of humans and for the moderation of agriculture. This calls for the design of versatile nanosensors capable of sensing toxic POPs with high sensitivity and selectivity. Inspired by this, the sensing characteristics of carbon nitride (C3N5) monolayers toward selected POPs are reported, such as Dichlorodiphenyltrichloroethane (DDT), Methoxychlor (DMDT), Fenthion (FT), Fenitrothion (FNT), and Rennol (RL), employing density functional theory calculations. Analysis of results predicts adsorption energies of −0.93, −1.55, −1.44, −0.98, and −1.15 eV for DDT, DMDT, FT, FNT, and RM, respectively, on C3N5 monolayers. Significant charge transfers among organic pollutants and C3N5 lead to distinct electronic properties of the conjugated complexes, revealed by the density of states, electrostatic potential, and work function calculations. To detect the selected pollutants in high humidity, the effects due to aqueous medium are considered. Additionally, a statistical thermodynamic analysis utilizing the Langmuir adsorption model is utilized to explore the influence of temperature and pressure. [ABSTRACT FROM AUTHOR]

Introduction: Methoxychlor (MXC) is an organochlorine pesticide (OCP) that was formerly used worldwide as an insecticide against pests and mosquitoes. However, MXC is not biodegradable and has lipophilic characteristics; thus, it accumulates in organisms and affects reproductive function. MXC, as an estrogenic compound, promotes oxidative stress, induces oxidative stress damage to ovarian follicles, and causes miscarriages and stillbirths in females. In this research endeavor, our primary objectivewas to explore the ramifications of MXC regarding the developmental processes occurring during the initial stages of embryogenesis in pigs. Methods: In this study,we counted the blastocyst rate of early embryos cultured in vitro. We also examined the reactive oxygen species level, glutathione level, mitochondrial membrane potential, mitochondrial copy number and ATP level in four-cell stage embryos. Finally, apoptosis and DNA damage in blastocyst cells, as well as pluripotency-related and apoptosis-related genes in blastocyst cells were detected. The above experiments were used to evaluate the changes ofMXC damage on early parthenogenetic embryo development. Results and Discussion: The results showed that early embryos exposed to MXC had a significantly lower cleavage rate, blastocyst rate, hatching rate, and total cell count compared with the control group. It was also of note that MXC not only increased the levels of reactive oxygen species (ROS), but also decreased the mitochondrialmembrane potential (ΔΨm) andmitochondrial copy number during the development of early embryos. In addition, after MXC treatment, blastocyst apoptosis and DNA damage were increased, decreased cell proliferation, and the expression of pluripotency-related genes SOX2, NANOG, and OCT4 was down-regulated, while the expression of apoptosis-related genes BAX/BCL-2 and Caspase9 was up-regulated. Our results clearly show that MXC can have deleterious effects on the developmental processes of early porcine embryos, establishing the toxicity of MXC to the reproductive system. In addition, the study of this toxic effectmay lead to greater concern about pesticide residues in humans and the use of safer pesticides, thus potentially preventing physiological diseases caused by chemical exposure. [ABSTRACT FROM AUTHOR]

This study investigated the concentration distribution characteristics and environmental risk assessment of 17 newly-used organochlorine pesticides in Huangpu River. In a total of 22 water samples, except for three newly-used organochlorine pesticides of Tecnazene, Methoxychlor and Quinoxyfen which were not detected, 14 other newly-used organochlorine pesticides were detected. Concentrations of the all organochlorine pesticides ranged from 0.272 to 0.924 ng/L (median: 0.467 ng/L) in all water samples, with higher concentrations of clomazone and oxadiazon. In addition, oxadiazon exhibited a significant and gradual downward trend in the upper reaches of the River, and the changing trend was basically in line with the first-order kinetics, with the half-life of 36.87 h (R²=0.73,P=0.024). The average ecological environmental risk coefficient (RQ) of newly-used organochlorine pesticides in Huangpu River is 0.001 3, indicating that the overall ecological environmental risk is still at a very low level. [ABSTRACT FROM AUTHOR]

Endocrine-disrupting chemicals found in many commercial products may interfere with the normal functioning of the endocrine system and are unsafe because of their cumulative effect on the human body. However, little is known about the effects of combinations of endocrine-disrupting chemicals in humans. Methoxychlor and bisphenol A are toxic to male reproductive organs. Therefore, we studied the effects of methoxychlor and bisphenol A on male reproductive function. Male mice were divided into four treatment groups: control, 400 mg methoxychlor, 1 mg bisphenol A, and 400 mg methoxychlor + 1 mg bisphenol A/kg/day. Methoxychlor and bisphenol A were dissolved in sesame oil and acetone and administered orally for 4 weeks. After administration, the weight and histological changes in the testicles and epididymis, sperm count and health were observed biochemical tests and whole blood counts were performed. The results showed that the mice in the bisphenol A and methoxychlor + bisphenol A groups gained more weight than those in the control and methoxychlor group. The weights of the testes and epididymis were higher in the experimental groups than in the control. Sperm motility and progression were significantly reduced in the bisphenol A and methoxychlor + bisphenol A groups. Histological observation showed a reduced number of sperm, smaller seminiferous tubules, and destroyed lumen in the methoxychlor + bisphenol A group compared to the other groups. In conclusion, our study showed that methoxychlor and bisphenol A destroy male reproductive tissues and decrease sperm quality.

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The presence of methoxychlor (MXC) in soil and wastewater is considered a nonnegligible environmental threat. Herein, Fe3O4@Fe(0) was obtained by NaBH4 reduction of Fe3O4 nanoparticles and served as a carrier for laccase to construct catalyst. The catalyst was evaluated for the degradation of MXC in treated wastewater and soil with 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) being used as cocatalyst. The removal rate of MXC in wastewater and soil was found to be 89% and 88% in optimum conditions, and the influences of initial MXC concentration, pH, and temperature on the degradation rate were evaluated. The metabolites including 2-methylpentane, 3-methylpentane, and n-pentane of MXC were identified, and possible degradation mechanisms were proposed. Overall, this work successfully demonstrates not only the ability to degrade MXC in different circumstances but also provides a new idea for environmental remediation in the future. [ABSTRACT FROM AUTHOR]

The Navachiste complex (NAV) is impacted by neighbored human activities and is located in the southwestern coastal zone of the Gulf of California. The study determines the trace metal (TM) and organochlorine pesticides (OCP) health risk content in the edible tissue of Sphoeroides spp. from NAV. The daily intakes (EDI), target hazard quotient (THQ), hazard index (HI), and carcinogenic and non-carcinogenic risks were calculated. Twenty OCP and seven TM were detected. Cd, Cu, Fe, Mn, Pb, and Zn were above MRLs. The γ‒Chlordane was the most frequent OCP. The highest average concentration was for α‒HCH, followed by γ‒chlordane. With the high ratios of γ‒HCH, p, p′‒ DDD and p, p′‒DDD, and the absence of p, p′‒ DDT, the higher ratios for dieldrin and endrin than for aldrin, α‒ chlordane, γ‒chlordane, heptachlor, and heptachlor epoxide indicates historical contamination. In contrast, the residual products of methoxychlor, endosulfan, and its isomers indicate endosulfan's recent use. The TM EDI, THQ > 1 (at 120 g day−1), and the ILCR (> 1 × 10–6) were above minimum levels, showing a high-risk potential for cancer development in the long term. [ABSTRACT FROM AUTHOR]

This study investigated the occurrence and seasonal distribution of different classes of pesticides in surface waters of the Ondas River Watershed, as well as potential risks to the aquatic health and human water consumption in the western region of Bahia state, Brazil. Two gas chromatography-mass spectrometry analytical methods were applied to monitor 34 pesticides in water samples collected during both the dry and rainy seasons at 17 sites. Upon individual analysis, only γ-HCH, methoxychlor, demeton-S, methyl parathion, fenitrothion, chlorpyrifos, and azoxystrobin exhibited statistically significant differences between seasons. During rainy season, concentration medians of residues were higher for γ-HCH (74.7 ng L−1), methoxychlor (25.1 ng L−1), and azoxystrobin (47.2 ng L−1), potentially linked to historical contamination or illegal use. Conversely, pesticides like methyl parathion, fenitrothion, and chlorpyrifos, belonging to the organophosphate class, showed higher concentration medians in the dry period, measuring 75.1, 5.50, and 10.8 ng L−1, respectively, probably due to region crop activities. The risk quotient (RQ) assessment for aquatic life indicated that 59.0% of the samples in the dry season and 76.0% in the rainy season had RQ values greater than one, signifying a critical scenario for species conservation. Regarding human consumption, elevated risks were observed for heptachlor in both sampling periods and for azoxystrobin during the rainy season, surpassing RQ levels above 1, indicating danger in untreated water ingestion. Additionally, 24.0% and 53.0% of the samples in the dry and rainy seasons, respectively, contained at least one pesticide exceeding the EU resolution limit (100 ng L−1). Therefore, considering this information, implementing mitigation measures to avoid the river's contamination becomes imperative. [Display omitted] • 34 pesticides in surface waters of the Ondas River Watershed (ORW) under study. • Pesticide residues has been found widely distributed in the ORW. • Each pesticide residue was quantified in at least one sample. • Heptachlor exceeds the maximal permitted level in Brazilian and EU laws. • The risk quotient (RQ) assessment indicated a critical scenario for aquatic life. [ABSTRACT FROM AUTHOR]

This study investigated the impact of neonatal exposure to endocrine-active compounds (EACs): flutamide (antiandrogen), 4- tert -octylphenol (an estrogenic compound), and methoxychlor (an organochlorine insecticide exhibiting estrogenic, antiestrogenic and antiandrogenic activities) on androgen production within porcine adrenal glands. The expression of genes related to androgen synthesis and the level of androgen production were analyzed (i) in the adrenal glands of piglets exposed to EACs during the first 10 days of life (in vivo study), and (ii) in adrenal explants from sow-fed or formula-fed 10-day-old piglets incubated with EACs (ex vivo study). EACs affected the expression of genes linked to adrenal androgen biosynthesis. The prominent effect of methoxychlor on downregulation of StAR , CYP11A1 and HSD3B and upregulation of CYP17A1 and SULT2A1 were demonstrated. Furthermore, our study revealed divergent response to EACs between sow-fed and formula-fed piglets, suggesting that natural feeding may provide protection against adverse EACs effects, particularly those interfering with estrogens action. • EACs effects on the adrenal androgen production were studied in piglets. • OP elevated A4, while high dose of MXC reduced DHEA adrenal secretion. • MXC decreased StAR , CYP11A1 and HSD3B , while increased CYP17A1 and S ULT2A1 expression. • Divergent EACs effects were observed in sow-fed vs. formula-fed piglets. • Natural feeding influences expression levels of some androgen synthesis-related genes. [ABSTRACT FROM AUTHOR]

This study investigated the spatial distributions and seasonal variations of 19 CUPs in the coastal areas of the Shandong Peninsula and its surrounding rivers and assessed their ecological risk. In freshwater and seawater, insecticides (chlorpyrifos, methoxychlor, and pyridaben), as well as fungicides (fenarimol) and herbicides (dichlobenil) were the main pollutants (Detection Frequency: 100 %). Spatially, during winter, the regional pollution levels of Σ 19 CUPs in seawater showed a trend of Laizhou Bay (LZB, mean:4.13 ng L−1) > Yellow River Estuary (YRE, mean:2.57 ngL−1) > Bohai Bay (BHB, mean:2.21 ng L−1) > Yanwei Area (YWA, mean:1.94 ng L−1). The similarities of major substances between rivers and the marine environment suggest that river discharge is the main source of CUPs pollution in coastal areas. In summer, CUPs in rivers posed a high risk. In winter, the risk significantly decreased, indicating a moderate overall risk. Seawater exhibited a low risk in winter. [Display omitted] • Agricultural activities are the main sources of CUPs in rivers. • River discharges are the major source of CUPs in coastal waters. • Coastal currents play an important role in the dispersion of CUPs. • CUPs pose a high risk to fish in summer rivers. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyse the content of OHCs and NDL-PCBs in wild boar population living in densely populated flatland region with intensive agricultural production. A total of 82 liver samples were analysed by GC-MS method, revealing the presence of minimum one residue in the liver of the majority of animals (92.7%). Most commonly detected residues included ∑ HCH (64.6%), ∑endrin (56.1%) and ∑dieldrin (32.3%). Mean concentrations were in the range ∑endrin > ∑dieldrin > ∑HCH > ∑NDL-PCB > ∑DDT > ∑CHL > ∑endosulfan > methoxychlor. The dominant compound within the total content of NDL-PCBs was PCB 153 (76%). The assessment of daily intake and determination of Health Index indicated that in 6.1% of the samples the consumption of one single portion of wild boar liver would be harmful to human health due to the presence of ∑endrin or NDL-PCBs. [ABSTRACT FROM AUTHOR]

This study investigated the level, composition, and spatial and vertical distribution of the organochlorine pesticides (OCPs) at 0–2 cm and 2–20 cm in the agricultural surface soils from Southeastern to Central-western Tanzania. Although the most abundant OCPs were DDT with a mean concentration of 2.29 ng/g, dieldrin (1.57 ng/g), and methoxychlor (0.79 ng/g), HCH was the most dominant (with detection frequency of 88%). OCP dominance was in the Southern Highlands, which is the most productive agricultural zone. Though there were indicators of recent inputs for some sites, OCP contamination was mainly historical. DDT contamination was dominated by p,p′-DDE and resulted from both technical DDT and dicofol while HCH contamination was dominated by γ-HCH and resulted from both technical HCH and lindane. Based on depth, the OCPs dominated mainly the upper 2 cm, which was associated with soil and environmental factors rather than recent inputs since most of the detected compounds were historical. Nevertheless, some sites showed exceptional high abundance in the lower soil with more concentration of parent compounds. Therefore, this study recommends the need for further studies on the influence of soil properties on OCPs' transport in the soil, surface water, and air. Besides, detection of recent inputs at some sites calls for more mapping of the OCPs in the country to strengthen their control and prevention of future risks. [ABSTRACT FROM AUTHOR]

Three sampling campaigns were performed in the Lis River (Leiria, Portugal) in February of 2018, November of 2018, and May of 2019. River water and wastewater (influent and effluent) samples of two wastewater treatment plants were target of the study. A total of 25 samples were collected and 50 pesticides were monitored, including organochlorines, triazines, pyrethroids, and organophosphorus, among others. Most of the detected pesticides were insecticides and mainly organochlorines. Concentrations between 1.29 and 2134 ng/L were found. Aldrin, γ-HCH, and cypermethrin were detected in some samples in μg/L, being γ-HCH the pesticide most frequently detected with concentration in μg/L level. The pesticides with the highest detection frequency were (i) cypermethrin, HCB, methoxychlor, and ζ-HCH in river waters; (ii) isoproturon, cypermethrin, methoxychlor, pyrimethanil, γ-HCH, dieldrin, diuron, α-HCH, and α-endosulfan in effluents; and (iii) diuron and isoproturon in influents. The detection of the organochlorides and their degradation products is a consequence of their persistence in the environment, as their usage has long been prohibited in the European Union. Pesticides were grouped by their types in herbicides, insecticides, or fungicides and the detection and concentration for each type were discussed with the climatic conditions. Pesticide toxicity index was determined in the samples collected in the river. [ABSTRACT FROM AUTHOR]

In time the environmental conditions could damage textiles (materials/artifacts) causing the need to develop better non-destructive or at least micro-destructive analysis techniques of the samples. There are ethnographic textile artifacts that were treated in the past with various pesticides, that have not been mentioned in any document. These are often re-treated with chemicals by museum staff as a method of preventing pest infestation. Due to the progressive use of many pesticides, this paper was focused on the detection and quantification of three pesticides: malathion, methoxychlor, and permethrin (cis- and trans-isomers). Gas chromatography is one of the most widely used analytical techniques for characterizing volatile organic compounds and therefore was the analytical method of choice for the present study. Because these analytes are found at trace levels, the detection and quantification limits of analytes are very small and it is necessary to optimize and validate a SIM method - that allows the mass spectrometer to detect specific compounds with high sensitivity. In SIM mode, the instrument is set to collect data at selected masses of interest, thus increasing the accuracy and precision of the quantitative results. The present paper is aimed to develop this type of method with specificity and selectivity, high precision (expressed in terms of repeatability and intermediate accuracy), accuracy, suitable working range and linearity, and high degree of series' homogenity. [ABSTRACT FROM AUTHOR]

Endocrine disrupting chemicals are chemicals that interfere with any aspect of the endocrine system. Several natural and synthetic chemicals, including pesticides, have been identified as endocrine disruptors, which potentially inhibit the reproductive activity of the hormonal system. The pervasive occurrence with trace level concentrations and extensive variety are the reported characteristics of these chemicals. In this study, a dispersive liquid‐liquid microextraction method coupled with gas chromatography and mass spectrometry for the determination of eight potential endocrine disruptor pesticides (Lindane, Diazinon, Fenitrothion, Malathion, Aldrin, α‐Endosulfan, β‐Endosulfan, Methoxychlor) in bovine milk samples was developed. Several parameters that can influence the extraction efficiency were studied. Under optimized conditions, the calibration curves of all eight analytes presented coefficient of determination higher than 0.998 (range level of 2.0‐1000 ng/mL). The limits of detection and quantification ranged from 0.90 to 5.00 ng/mL and 2.50 to 15.0 ng/mL, respectively. [ABSTRACT FROM AUTHOR]

Follicular granulosa cells (GCs) form an important association with follicle's survival and health that determines ovulation. Apoptosis induction in GCs leads to follicular atresia and infertility problems. The present study aims at assessing the ultrastructural toxicity of methoxychlor (MXC), an organochlorine insecticide and reproductive toxin, on structural aspects of GCs owing to its potential for inducing apoptosis and the ameliorating potential of N-acetyl-L-cysteine (NAC) in this toxicity. The ultrastructural morphology revealed MXC induced degenerative changes in GCs like loss of cellular junction complexes and membrane integrity; nuclear abnormalities like occurrence of condensed and marginated chromatin, crescent shaped or blebbed nucleus; presence of disrupted mitochondria with disrupted cristae, vacuolization, empty spaces, large number of homogenous lipid droplets and extensive network of rough endoplasmic reticulum and several cytoplasmic processes at various doses of MXC with maximum degeneration observed at 100 pg/ml. NAC supplementation reduced the observed apoptotic characteristics of GCs with most significant changes at 5- and 10 mM concentration. Thus, it is evident that MXC acts as an apoptotic inducer in GCs that influences the quality of antral follicles in mammals; however, NAC, with its anti-oxidative and anti-inflammatory properties, turns out to be a potential therapeutic and anti-apoptotic agent against MXC toxicity. [ABSTRACT FROM AUTHOR]

Oxidative stress occurs when cellular mechanisms to regulate levels of reactive oxygen species (ROS) are overwhelmed due to overproduction of ROS and/or deficiency of antioxidants. This chapter describes accumulating evidence that oxidative stress is involved in ovarian toxicity caused by diverse stimuli, including environmental toxicants. There is strong evidence that ROS are involved in initiation of apoptosis in antral follicles caused by several chemical and physical agents. Although less attention has been focused on the roles of ROS in primordial and primary follicle death, several studies have shown protective effects of antioxidants and/or evidence of oxidative damage, suggesting that ROS may play a role in these smaller follicles as well. Oxidative damage to lipids in the oocyte has been implicated as a cause of persistently poor oocyte quality after early life exposure to several toxicants. Developing germ cells in the fetal ovary have also been shown to be sensitive to toxicants and ionizing radiation, which induce oxidative stress. Recent studies have begun to elucidate the mechanisms by which ROS mediate ovarian toxicity.

Oxidative stress occurs when cellular mechanisms to regulate levels of reactive oxygen species (ROS) are overwhelmed due to overproduction of ROS and/or deficiency of antioxidants. This chapter describes accumulating evidence that oxidative stress is involved in ovarian toxicity caused by diverse stimuli, including environmental toxicants. There is strong evidence that ROS are involved in initiation of apoptosis in antral follicles caused by several chemical and physical agents. Although less attention has been focused on the roles of ROS in primordial and primary follicle death, several studies have shown protective effects of antioxidants and/or evidence of oxidative damage, suggesting that ROS may play a role in these smaller follicles as well. Oxidative damage to lipids in the oocyte has been implicated as a cause of persistently poor oocyte quality after early life exposure to several toxicants. Developing germ cells in the fetal ovary have also been shown to be sensitive to toxicants and ionizing radiation, which induce oxidative stress. Recent studies have begun to elucidate the mechanisms by which ROS mediate ovarian toxicity.

In this study, the acute impacts of aqueous methoxychlor exposure on the viability, locomotive behavior, and heartrate of Daphnia magna was assessed. Adults were exposed to 0 (ethanol control), 1, 2.5, 5, or 10 µg/L of methoxychlor for 48 hr using a static exposure assay. After 24 hr mobility was quantified using automated behavioral analysis software and differences in mortality and heartrate assessed after 24 and 48 hr. Exposure caused an increase in mortality after 48 hr, with effects seen in as little as 24 hr in the 10 µg/L treatment. Decreases in speed, total distance traveled, and frozen events were observed after 24 hr. Heartrate in the 10 µg/L treatment was depressed after 24 hr, with decreases in the 2.5 and 5 µg/L treatments observed after 48 hr. These results provide an expanded understanding of the impacts of a well-established legacy organochlorine pesticide on a model invertebrate. [ABSTRACT FROM AUTHOR]

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work focuses on the development, validation and application of an analytical method for the determination of twenty organochlorine pesticides (OCPs) in human tissues using salting-out liquid–liquid extraction and dispersive liquid–liquid microextraction for sample preparation and gas chromatography–mass spectrometry to analyze the obtained extracts. Measurement of the concentration levels of these toxics in tissues can be used to assess the risk of the population to exposure. The linearity of the proposed method was verified in the 10–1,000 ng/g range. The sensitivity was evaluated calculating the limits of detection (LODs) for 20 OCPs (α-, β-, γ- and δ-hexachlorocyclohexane (HCH), α- and β-endosulfan, endosulfan sulfate, aldrin, dieldrin, endrin, endrin ketone, endrin aldehyde, α- and γ-chlordane, 4,4′-dichlorodiphenyltrichloroethane, 4,4′-dichlorodiphenyldichloroethylene (DDE), 4,4′-dichlorodiphenyldichloroethane, heptachlor, heptachlor epoxide and methoxychlor), most of them being found between 1.0 and 16 ng/g. The intra- and interday precisions were <12% for relative standard deviation values. The accuracy of the method was evaluated by recovery studies, which gave recovery percentages in the 85–109% range. Seven different tissues (liver, kidney, heart, spleen, lung, brain and abdominal fat) from eight autopsies were analyzed, and only three cases were seen to have β-HCH and 4,4′-DDE in abdominal fat, while 4,4′-DDE was also detected in the heart of one case. The rest of the samples were free of the studied OCPs at least above the corresponding LODs. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the effects of neonatal exposure to methoxychlor (MXC), a synthetic organochlorine used as an insecticide with estrogenic, antiestrogenic, and antiandrogenic activities on ovarian follicles of adult pigs. Piglets were injected with MXC (20 μg/kg body weight) or corn oil (controls) from postnatal Day 1 to Day 10 (n = 5 per group). Then, mRNA expression, protein abundance and immunolocalization of growth and differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15), anti-Müllerian hormone (AMH) and cognate receptors (ACVR1, BMPR1A, BMPR1B, TGFBR1, BMPR2, and AMHR2), as well as FSH receptor (FSHR) were examined in preantral and small antral ovarian follicles of sexually mature gilts. The plasma AMH and FSH levels were also assessed. In preantral follicles, neonatal exposure to MXC increased GDF9, BMPR1B, TGFBR1, and BMPR2 mRNAs, while the levels of AMH and BMP15 mRNAs decreased. In addition, MXC also decreased BMP15 and BMPR1B protein abundance. Regarding small antral follicles, neonatal exposure to MXC upregulated mRNAs for BMPR1B, BMPR2, and AMHR2 and downregulated mRNAs for AMH, BMPR1A, and FSHR. MXC decreased the protein abundance of AMH, and all examined receptors in small antral follicles. GDF9 and BMP15 were immunolocalized in oocytes and granulosa cells of preantral follicles of control and treated ovaries. All analyzed receptors were detected in the oocytes and granulosa cells of preantral follicles, and in the granulosa and theca cells of small antral follicles. The exception, however, was FSHR, which was detected only in the granulosa cells of small antral follicles. In addition, MXC decreased the plasma AMH and FSH concentrations. In conclusion, the present study may indicate long-term effects of neonatal MXC exposure on GDF9, BMP15, AMH, and FSH signaling in ovaries of adult pigs. However, the MXC effects varied at different stages of follicular development. It seems that neonatal MXC exposure may result in accelerated initial recruitment of ovarian follicles and impaired cyclic recruitment of antral follicles.

In this study, we synthesized Fe 3 O 4 using the co-precipitation method and then prepared magnetic carrier LDHs@Fe 3 O 4 by immobilizing layered double hydroxide on Fe 3 O 4 by in situ growth method. Cellulase was immobilized on this magnetic carrier by using glutaraldehyde as a coupling agent, which can be used for degrading Methoxychlor (MXC). The results demonstrated the maximum MXC removal efficiency of 73.4% at 45 °C and pH = 6.0 with excellent reusability. Through kinetic analysis, it was found that the degradation reaction conforms to the Langmuir-Hinshelwood model and is a first-order reaction. Finally, according to the EPR analysis, the active radicals in the system were found to be OH· and the degradation mechanism was proposed in combination with LC-MS. This study provides a feasible method for degrading organochlorine pesticides, which can be used for groundwater purification.

This study evaluated the potential health risk of OCPs in selected protein foods. A total of 66 food samples were collected from selected areas in Abeokuta, southwestern Nigeria. Food samples were analyzed for OCPs using the standard method. OCP data were analysed for descriptive and inferential statistics. Health risk assessment was conducted for non-carcinogenic {Hazard Quotient (HQ), Hazard Index (HI) and Cancer Risk (CR)}. The ΣOCP concentration was observed highest in pork (42.20 ± 33.33 mg kg−1) of which methoxychlor and dieldrin represented 63 and 28%, respectively. The HIs of OCPs in protein foods were generally greater than 1.0 indicating adverse effects. The ΣCR data showed carcinogenic effects in protein foods with values greater than the acceptable limit of 1.0 × 10−4. [ABSTRACT FROM AUTHOR]

Endocrine-disrupting chemicals (EDC) are widespread in the built and natural environments. Heightened public awareness of their potential danger has led to concern about whether EDC and their metabolites have significant negative biological effects. Studies have shown that EDC like DDT and other organochlorine pesticides, such as methoxychlor (MXC), have adverse effects on immune cells, but no studies have addressed the impact of HPTE, the primary metabolite of MXC. To elucidate the presence and significance of HPTE adverse effects, this study explored the impact of HPTE on a critical window and component of immune system development, embryonic T-cell development. Lesions at this phase of development can lead to lifelong immune dysfunction and increased incidence of immune disease, such as autoimmunity. Embry-onic thymocytes (GD 16-18) from C57BL/6 mice were subjected to an in vitro differentiation culture that mimicked early steps in thymocyte development in the presence of 0.005, 0.05, 0.5, 5, or 50 μM HPTE, or a model endocrine disruptor, DES. The results indicated that compared to the vehicle control, HPTE- and DES-induced death of thymocytes. Annexin-V staining and Caspase 8, markers of programed cell death, revealed that the loss of cells was due at least in part to induction of apoptosis. Moreover, HPTE-induced cell death not only resulted in selective loss of double positive thymocytes, but also loss of developing CD4 intermediate cells (post-double positive partially differentiated thymocyte population). Phenotypic analysis of thymocyte maturation (T-cell receptor, TCR) and TCR ligation (CD5) surface markers revealed that surviving embryonic thymocytes expressed low levels of both. Taken together these data demonstrate that immature embryonic thymocytes are sensitive to HPTE exposure and that HPTE exposure targets thymocyte populations undergoing critical differentiation steps. These findings suggest HPTE may play a pivotal role in MXC exposure-induced immune dysfunction.

Being the largest agriculture country in the Arab world, Egypt was one of the major consumer of organochlorine pesticides (OCPs) in this area, continued to have a heavy burden of OCPs in the environment. There is growing concern that OCPs could pass from the maternal circulation through the placenta to the fetal circulation and pose several health risks to their fetuses. The current study was intended to identify OCPs residue exposure in healthy pregnant women and to justify the potential impacts of these residues on their fetuses. In this study, the prevalence of 18 OCPs was estimated in 81 maternal and cord blood samples, using Agilent 7890, gas chromatograph equipped with micro-electron capture detector (GC-μECD). Our data signposted that the heptachlor epoxide has the highest detection rate among all residues in both maternal (32%) and cord blood serum (27.16%). DDTs were still quantifiable, but with the lowest quantifiable percentage. More than 85% of mothers' serum with detectable residues transfer OCPs residue to their fetuses in a statistically significant manner (x = 42.9, p value < 0.001). The present findings showed no significant growth retardation, or preterm delivery induced by in utero exposure to the most abundant residues. There is growing evidence that exposure to OCPs residue has profound impact on sex ratio. Methoxychlor, in this study be deemed as testosterone triggers which yields high boys ratio (x = 4.37, p < 0.05). In conclusion, Egypt continued to have a heavy burden of OCPs residues, and fetuses and infants are especially the most vulnerable groups to their adverse health effects. Exposure to OCPs may disrupt the maternal hormones, which regulate the offspring gender, but these results need to be validated in larger sample sizes. [ABSTRACT FROM AUTHOR]

Numerous chemicals derived from human activity are now disseminated in the environment where their exert estrogenic endocrine disrupting effects, and therefore represent major health concerns. The present study explored whether Methoxychlor (MXC), an insecticide with xenoestrogens activities, given during the perinatal period (from gestational day 11 to postnatal day 8) and at an environmentally dose [20 μg/kg (body weight)/day], would affect reproductive physiology and sexual behavior of the offspring in mice. While MXC exposure did not induce any differences in the weight gain of animals from birth to 4 months of age, a clear difference (although in opposite direction according to the sexes) was observed on the anogenital distance between intact and exposed animals. A similar effect was also observed on preputial separation and vaginal opening, which reflects, respectively, in males and females, puberty occurrence. The advanced puberty observed in females was associated with an enhanced expression of kisspeptin cells in the anteroventral periventricular region of the medial preoptic area. Exposure to MXC did not induce in adult females changes in the estrous cycle or in the weight of the female reproductive tract. By contrast, males showed reduced weight of the epididymis and seminiferous vesicles associated with reduced testosterone levels and seminiferous tubule diameter. We also showed that both males and females showed deficits in mate preference tests. As a whole, our results show that MXC impacts reproductive outcomes. [ABSTRACT FROM AUTHOR]

Purpose: Sediments are natural archives to record the occurrence and sources of organochlorine pesticides (OCPs). Most previous studies on historical occurrence and sources of OCPs in China only focused on DDTs and HCHs. Comprehensive knowledge of historical occurrence and sources of persistent OCPs in China are scarce. Materials and methods: One 20-cm sediment core was collected from the third largest freshwater lake (Lake Taihu) in China, then sliced every 1 cm, dated with 137Cs and 210Pb, and used for the analysis of 21 OCPs. Isomer ratios and principal component analysis (PCA) were applied to apportion the historical sources of the OCPs in this lake. Results and discussion: Three concentration peaks of OCPs were observed in the middle-late 1950s, early-middle 1980s, and the middle 2000s. The average concentration of ΣDDX was 238.55 ± 55.43 ng gdw−1 from 1948 to 2012. p,p′-DDT was the dominant congener of DDX, mostly derived from the legacy technical DDT. The average concentration of ΣHCHs, aldrin, heptachlor epoxide, endosulfan sulfate, methoxychlor, heptachlor, trans-chlordane, cis-chlordane, endosulfan I, endrin, diendrin, endosulfan II, diendrin aldehydrate, and diendrin ketone were 24.56 ± 6.90, 10.35 ± 3.26, 9.51 ± 1.88, 7.37 ± 1.81, 7.01 ± 2.82, 2.60 ± 0.81, 0.63 ± 0.24, 3.21 ± 1.25, 1.04 ± 0.29, 3.89 ± 2.61, 5.67 ± 1.59, 1.07 ± 0.19, 1.09 ± 0.22, and 1.32 ± 0.33 ng gdw−1. Conclusions: Dicofol and p,p′-DDT-containing anti-fouling paints may be responsible for the current input of p,p′-DDT. Most of the HCHs were derived from the legacy technical HCHs, but there was input of lindane as well. PCA indicated that the legacy technical DDTs, HCHs, heptachlor, chlordane, aldrin, and endrin, the current input of p,p′-DDT, methoxychlor, and endosulfan, and microbial transform of γ-HCH to α-HCH were the dominant sources for the 21 OCPs in Lake Taihu. [ABSTRACT FROM AUTHOR]

In the present study, the effects of short‐term methoxychlor exposure on the viability, reproduction, and locomotor behavior of adult seminole ramshorn snails (Planorbella duryi) was assessed. To examine impacts on viability and behavior, individuals were exposed to a water control, vehicle control, or 12.5, 50, 100, 250, 500, or 1000 μg/L of methoxychlor for 48 h; and differences in mortality and locomotor behavior assessed using the freely available ToxTrac software. To determine impacts on reproduction, pairs of snails were exposed to a vehicle control and 12.5, 25, 50, 100, and 250 μg/L of methoxychlor for 9 d; and the number of clutches and eggs laid quantified every 24 h. Methoxychlor concentrations in treatments were determined using gas chromatography. Complete mortality was observed in the 500 μg/L and 1000 μg/L treatments after 48 h and in the 250 μg/L treatment after 9 d. Decreases in the number of egg clutches were observed in all treatments, and the number of eggs laid decreased starting in the 25 μg/L treatment. Decreases in average speed, mobile speed, and total distance traveled, as well as a significant increase in frozen events, were also observed. Our results suggest that methoxychlor exposure causes detrimental effects on several nonlethal endpoints in a nonmodel aquatic invertebrate species and that the analysis of locomotor behaviors serves as a reliable, sensitive endpoint for ecotoxicology testing. Environ Toxicol Chem 2019;39:220–228. © 2019 SETAC [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the level of the organochlorine pesticides (OCPs) in meat, liver and skin of common carp. Fish were collected in spring and in autumn from fishpond that receives purified water from slaughterhouse. OCPs, including α-HCH, β-HCH, δ-HCH, lindane, heptachlor, aldrin, heptachlor epoxide, trans-chlordane, cis-chlordane, endosulfan I, DDE, dieldrin, endrin, DDD, endosulfan II, dichlorodiphenyltrichloroethane (DDT), endosulfan sulphate, methoxychlor, and endrin ketone, were determined by using a gas chromatography–mass spectrometry method. OCPs were present at low concentrations and only aldrin was detected in all examined tissues. The estimated daily intake for OCPs via common carp from integrated system of production was at the lower level compared with the acceptable daily intake recommended by different organisations, showing no significant risk on consumers. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides (OCPs) are a more persistent and lipophilic group of insecticides. The present study aims to evaluate the residues of OCPs in meat, liver, and kidney of the cattle and sheep. A total of 54 samples were obtained from butcheries and local markets in Birjand, east of Iran. The residual contents of aldrin; dieldrin; dichlorodiphenyltrichloroethane; and its metabolites (DDTs), endosulfan isomers, endrin, hexachlorocyclohexane isomers (HCHs), heptachlor, heptachlor epoxide, chlordans, methoxychlor, and hexachlorobenzene (HCB), were analyzed in all samples. OCP residues were extracted by using the QuEChERS technique and quantified by gas chromatography-mass spectrometry (GC-MS). All of the analyzed OCPs were lower than the detection limit. The findings showed that meat and edible organs marketed in this region enjoyed a good status in terms of the residues of OCP. Monitoring of pesticide residues in meat and edible organs is necessary from the public health point of view. [ABSTRACT FROM AUTHOR]

Introduction: Methoxychlor (MXC) is an organochlorine pesticide (OCP) that was formerly used worldwide as an insecticide against pests and mosquitoes. However, MXC is not biodegradable and has lipophilic characteristics; thus, it accumulates in organisms and affects reproductive function. MXC, as an estrogenic compound, promotes oxidative stress, induces oxidative stress damage to ovarian follicles, and causes miscarriages and stillbirths in females. In this research endeavor, our primary objective was to explore the ramifications of MXC regarding the developmental processes occurring during the initial stages of embryogenesis in pigs. Methods: In this study, we counted the blastocyst rate of early embryos cultured in vitro . We also examined the reactive oxygen species level, glutathione level, mitochondrial membrane potential, mitochondrial copy number and ATP level in four-cell stage embryos. Finally, apoptosis and DNA damage in blastocyst cells, as well as pluripotency-related and apoptosis-related genes in blastocyst cells were detected. The above experiments were used to evaluate the changes of MXC damage on early parthenogenetic embryo development. Results and Discussion: The results showed that early embryos exposed to MXC had a significantly lower cleavage rate, blastocyst rate, hatching rate, and total cell count compared with the control group. It was also of note that MXC not only increased the levels of reactive oxygen species (ROS), but also decreased the mitochondrial membrane potential (ΔΨm) and mitochondrial copy number during the development of early embryos. In addition, after MXC treatment, blastocyst apoptosis and DNA damage were increased, decreased cell proliferation, and the expression of pluripotency-related genes SOX2, NANOG , and OCT4 was down-regulated, while the expression of apoptosis-related genes BAX/BCL-2 and Caspase9 was up-regulated. Our results clearly show that MXC can have deleterious effects on the developmental processes of early porcine embryos, establishing the toxicity of MXC to the reproductive system. In addition, the study of this toxic effect may lead to greater concern about pesticide residues in humans and the use of safer pesticides, thus potentially preventing physiological diseases caused by chemical exposure., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2023 Geng, Jin, Quan, Huang, Shi, Hu, Chi, Kong, Zhang and Yu.)

Chiral mesoporous silica (SiO2) with helical structure was synthesized by using anionic surfactants as template. Pre-prepared graphene oxide (GO) was then loaded onto SiO2 to synthesize composite carrier chial-meso-SiO2@GO for the immobilization of laccase. The enzyme activity, thermostability, acid stability, and repeatability of the immobilized enzyme were significantly improved after immobilization. The chial-meso-SiO2@GO-immobilized laccase was then used for the degradation of MXC in aqueous phase. The degradation conditions, including temperature, time, pH, MXC concentration, and the dose of immobilized enzyme for cellulosic hydrolysis, were optimized. The optimum conditions for degradation of methoxychlor were selected as pH 4.5, MXC concentration 30 mg/L, immobilized enzyme dose 0.1 g, the maximum MXC removal of over 85% and the maximum degradation rate of 50.75% were achieved after degradation time of six h at temperature of 45 °C. In addition, the immobilized cellulase was added into the immobilized laccase system to form chial-meso-SiO2@GO-immobilized compound enzyme with the maximum MXC degradation rate of 59.58%, higher than that of 50.75% by immobilized laccase. An assessment was made for the effect of chial-meso-SiO2@GO-immobilized compound enzyme on the degradation of MXC in soil phase. For three contaminated soils with MXC concentration of 25 mg/kg, 50 mg/kg, and 100 mg/kg, the MXC removals were 93.0%, 85.8%, and 65.1%, respectively. According to the GC-MS analyses, it was inferred that chial-meso-SiO2@GO-immobilized compound enzyme had a different degradation route with that of chial-meso-SiO2@GO-immobilized laccase. The hydrolysis by immobilized cellulase might attack at a weak location of the MXC molecule with its free radical OH and ultimately removed three chlorine atoms from MXC molecule, leading to generating small molecular amount of degradation product. [ABSTRACT FROM AUTHOR]

Chinese mitten crab, a featured macrobenthos, has been one of the most important economical aquatic species in China. This study assessed the accumulation of an organochlorine pesticide methoxychlor (MXC) in Chinese mitten crab during exposure to 1 mg/L of MXC. The results showed the residual concentration of MXC in the ovary and hepatopancreas reached 55.07 ± 2.64 ng/g and 34.51 ± 2.35 ng/g, respectively. After exposure, tubular vacuolization of epithelial tissues, condensed egg cells and obvious intervals between egg cell wall and stroma were observed in the hepatopancreas and ovary, respectively. Significant changes of three key metabolic enzymes in hepatopancreas were observed upon exposure to MXC. Compared to the control, acetylcholinesterase level was significantly higher at day 7 (0.15 ± 0.01 vs. 0.06 ± 0.00 U/mgprot); glutathione S-transferase level was elevated at both day 4 (12.01 ± 0.48 vs. 3.20 ± 0.44 U/mgprot) and day 7 (12.84 ± 1.01 vs. 8.22 ± 0.81 U/mgprot); superoxide dismutase was sharply increased at day 4 (21.20 ± 0.24 vs. 3.66 ± 0.60 U/mgprot) but decreased at day 7 (3.74 ± 0.12 vs. 9.44 ± 0.85 U/mgprot). Overall, dissolved MXC accumulated in lipid-rich tissues could cause damages on epithelial cells and egg cells and change metabolic activities of enzymes involved in antioxidative stress and detoxification processes. Unlabelled Image • Ovary is the target organ of methoxychlor (MXC) in Chinese mitten crab. • MXC exposure caused severe damages to hepatopancreas and ovary tissues. • MXC affected metabolic enzymes in anti-oxidation and detoxification processes. [ABSTRACT FROM AUTHOR]

Persistent organic pollutants, (POPs), are vast distributed compounds in environment which are recognized as one of the global pollution problems. These groups of materials being dangerous due to their high stability are accumulated in animal tissues and occurring in the food chain. One of the major paths through which persistent organic combinations access to human body is consuming polluted foods, particularly, fishes. Among aquatic animals, trout as one of the mostly consumed fishes in Tehran's food basket was studied. In this study, two categories of persistent organic pollutants: Organochlorine pesticides (OCPs) including HCB, Dieldrin, Methoxychlor, α-, ϒ-Chlordane, α-, β-Endosulfan and o,p'-DDE, p,p'-DDE, o,p'- DDT, p,p'-DDT and the second group Polychlonitated biphenyls (PCBs) including seven PCB congeners which are called indicator PCBs (IUPAC nos.: 28,52,101,118,138,153 and 180) were determined in trout by GC-MS/MS in MRM monitoring mode and LLE extraction. The average recoveries of OCPs and PCBs at five concentration levels (1, 2, 5, 10 and 20 ng/g for PCBs and 5 times for OCPs) were in the range of 73-112%. The relative standard deviations of POPs in fish were in the range of 1.4-17.9% for all of the concentration levels. The limit of detections (LODs) and the limit of quantitations (LOQs) were between 0.6-8.3 and 2-25 μg/kg, respectively. The results indicated the presence of organochlorine pesticides in trout and the levels of p,p'-DDE and p,p'-DDT were within the range of < LOQ -12.83 and < LOQ -10.2 ng/g ww (wet weight), respectively. According to the results, OCPs residues were lower than maximum residue levels set by European Council Directives. [ABSTRACT FROM AUTHOR]

The aim of this study is to identify the combined effect of multiple chemicals to the development of allergy. In this study, the effect of prenatal exposure to an organochlorine agent methoxychlor (MXC) and/or an organophosphate agent parathion (PARA) on trimellitic anhydride-induced allergic airway inflammation was examined in mice. Eosinophil infiltration in the bronchoalveolar lavage fluid (BALF) was significantly enhanced by MXC + PARA exposure compared to that of the control, MXC, and PARA groups. In the hilar lymph node, only slight increases in B-cell infiltration, as well as IL-6 and IL-9 secretions were observed in MXC + PARA group, and no effect was observed in the individual treatment groups. Our findings imply that prenatal exposure to some combinations of multiple chemicals may exacerbate the allergic inflammatory responses including eosinophils and cytokine production. [ABSTRACT FROM AUTHOR]

Paper provided the systematic data on the distribution and risk assessment status of organochlorine pesticides (OCPs) in sediment of the Tisza River (Serbia). The α-HCH, endrin ketone and methoxychlor are the most commonly found OCPs compounds. According to Serbian regulation concentrations of dieldrin, α-HCH, β-HCH and heptachlor were below limit values. In the Tisza River, sediment samples concentrations of aldrin, endrin, γ-HCH, endosulfans, heptachlor epoxide, p,p'-DDD, p,p'-DDE, p,p'-DDT were above limit values but below maximum concentration. Adverse effects are expected occasionally and slight potential health risks may exist to organisms based on the sediment quality guidelines. Upon exposure to organochlorine pesticides through non-dietary routes, results reported no potential cancer risk. The highest risk of cancer was through ingestion of contaminated sediments and minimal through inhalation routes. [ABSTRACT FROM AUTHOR]

Endocrine-disrupting chemicals (EDC) are widespread in the built and natural environments. Heightened public awareness of their potential danger has led to concern about whether EDC and their metabolites have significant negative biological effects. Studies have shown that EDC like DDT and other organochlorine pesticides, such as methoxychlor (MXC), have adverse effects on immune cells, but no studies have addressed the impact of HPTE, the primary metabolite of MXC. To elucidate the presence and significance of HPTE adverse effects, this study explored the impact of HPTE on a critical window and component of immune system development, embryonic T-cell development. Lesions at this phase of development can lead to lifelong immune dysfunction and increased incidence of immune disease, such as autoimmunity. Embry-onic thymocytes (GD 16-18) from C57BL/6 mice were subjected to an in vitro differentiation culture that mimicked early steps in thymocyte development in the presence of 0.005, 0.05, 0.5, 5, or 50 μM HPTE, or a model endocrine disruptor, DES. The results indicated that compared to the vehicle control, HPTE- and DES-induced death of thymocytes. Annexin-V staining and Caspase 8, markers of programed cell death, revealed that the loss of cells was due at least in part to induction of apoptosis. Moreover, HPTE-induced cell death not only resulted in selective loss of double positive thymocytes, but also loss of developing CD4 intermediate cells (post-double positive partially differentiated thymocyte population). Phenotypic analysis of thymocyte maturation (T-cell receptor, TCR) and TCR ligation (CD5) surface markers revealed that surviving embryonic thymocytes expressed low levels of both. Taken together these data demonstrate that immature embryonic thymocytes are sensitive to HPTE exposure and that HPTE exposure targets thymocyte populations undergoing critical differentiation steps. These findings suggest HPTE may play a pivotal role in MXC exposure-induced immune dysfunction. [ABSTRACT FROM AUTHOR]

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There is an ample epidemiological evidence to support the role of environmental contaminants such as bisphenol A (BPA) in breast cancer development but the molecular mechanisms of their action are still not fully understood. Therefore, we sought to analyze the effects of three common contaminants (BPA; 4-tert-octylphenol, OP; hexabromocyclododecane, HBCD) on mammary epithelial cell (HME1) and MCF7 breast cancer cell line. We also supplied some data on methoxychlor, MXC; 4-nonylphenol, NP; and 2-amino-1-methyl-6-phenylimidazo [4–b] pyridine, PhIP. We focused on testing the prolonged (two months) exposure to low nano-molar concentrations (0.0015–0.0048 nM) presumed to be oncogenic and found that they induced DNA damage (evidenced by upregulation of pH2A.X, pCHK1, pCHK2, p-P53) and disrupted the cell cycle. Some agents induced epigenetic (methylation) changes of tumor suppressor genes TIMP3, CHFR, ESR1, IGSF4, CDH13, and GSTP1. Obviously, the accumulation of these molecular alterations is an essential base for cancer development. Consistent with this, we observed that these agents increased cellular invasiveness through collagen. Cellular abilities to form colonies in soft agar were increased for MCF7. Toxic agents induced phosphorylation of protein kinase such as EGFR, CREB, STAT6, c-Jun, STAT3, HSP6, HSP27, AMPKα1, FAK, p53, GSK-3α/β, and P70S6 in HME1. Most of these proteins are involved in potential oncogenic pathways. Overall, these data clarify the molecular alterations that can be induced by some common environmental contaminants in mammary epithelial cells which could be a foundation to understand environmental carcinogenesis.