Absorption and Metabolism of Bisphenol A,a Possible Endocrine Disruptor,in the Aquatic Edible Plant,Water Convolvulus (Ipomoea aquatica)

Water convolvulus, a vegetable, absorbed bisphenol A (BPA), an endocrine disruptor, from the medium. One week later, no BPA could be detected in the plant, indicating that BPA had been metabolized in the plant. BPA monoglucoside was detected as the BPA base at ca. 10% in the roots, some in the stems, but none in the leaves. ²H-NMR analyses of MeOH extracts and hydrolyzates of the plant treated with BPA-d₁₆ showed the presence of metabolites (ca. 7% and 26%, respectively, as BPA equivalents) other than the glucoside. Over 50% of BPA might be polymerized and/or tightly bound in the plant residues.     

Phytoremediation of Bisphenol A and Total Dissolved Solids by the Mangrove Plant,Bruguiera Gymnorhiza

Bruguiera gymnorhiza, an evergreen mangrove tree, is tolerant of bisphenol A (BPA) and has potential BPA removal capability. BPA is highly toxic to plants at high concentrations, wherein they exhibit damaged symptoms such as chlorosis, necrosis, and wilting. The LD₅₀ of BPA toxicity for this plant was statistically estimated to be 39.97 mg L^–1. B. gymnorhiza can reduce COD from 15408 ± 246 to 49 ± 30 mg L^–1 by (approximately 99% reduction of the initial value) and can reduce content to levels below the industrial effluent standard of Thailand (<120 mg L^–1) within 48 days. This plant can completely remove BPA from the solution within 51 days of treatment. Polysaccharides and organic acids were found in the solution and were caused by plant response to the toxicity of BPA. In addition, B. gymnorrhiza can also reduce total dissolved solids (TDS) and salinity in real wastewater. Therefore, B. gymnorrhiza has potential for removal of BPA and TDS in contaminated in wastewater.     

Simple and accurate determination of bisphenol A in red blood cells prepared with basic glycine buffer using liquid chromatography-electrochemical detection

For an accurate determination of bisphenol A (BPA) in red blood cells (RBC), the effect of pH on the concentration of BPA was investigated. Also, BPA recovery using ferric heme, methemoglobin (metHb) and hematin, were investigated to confirm whether BPA binds to ferric heme. BPA recovery in hemolysate was high at alkaline pH and was very low at acidic pH where oxyHb changed to metHb. BPA recovery decreased dose-dependently in metHb and hematin, but inorganic iron ions did not influence the recovery. These results suggested that BPA could be bound to ferric heme in RBC. The use of glycine-NaOH buffer (pH 11) as well as plasma had the highest recovery (97%). BPA was not detected in red blood cells of healthy adult volunteers (n=6). In sheep blood contaminated with BPA, BPA was detected in both plasma and RBC (10 times lower than in plasma), indicating that BPA could have migrated from plasma into RBC.     

GC-MS analysis of bisphenol A in human placental and fetal liver samples

A method based on extraction with acetonitrile, followed by solid-phase extraction, derivatization with acetic anhydride, and isotope dilution gas chromatography-mass spectrometry (GC-MS) analysis was applied to determine levels of free and conjugated BPA in human tissues. β-Glucuronidase was used to de-conjugate the glucuronized BPA in the samples. The method was validated using various animal organ meat samples including pork liver and kidney, beef and calf liver, chicken liver and heart; recoveries were from 85% to 112% at two spiking levels. The average method limit of quantification (LOQ) was estimated at 0.77 ng/g for placenta samples and 1.2 ng/g for fetal liver samples based on 10 times the signal to noise ratio. BPA was detected in all animal tissue samples, with concentrations ranging from 1.8 ng/g in beef and calf livers to 17.1 ng/g in pork kidney. The method was used successfully to determine both free and conjugated BPA levels in human placental and fetal liver tissue samples. BPA was detected in 86% of the placental samples; concentrations of free BPA in the positive samples ranged from 0.60 ng/g to as high as 64 ng/g with an average of 9.5 ng/g and a median of 3.0 ng/g, and conjugated BPA was as high as 7.8 ng/g. BPA was also detected in most of the fetal liver samples (57%); concentrations of free BPA in the positive samples ranged from 1.3 to 27 ng/g with an average of 8.5 ng/g and a median of 3.2 ng/g. Conjugated BPA was also detected in most of the liver samples analysed for total BPA, ranging from 0.64 to 20 ng/g with an average of 3.9 ng/g and a median of 1.5 ng/g. This study, while primarily designed as a method validation, has demonstrated that BPA can be detected in human fetal liver samples as early as the third month of fetal life. Further work will be conducted to validate these preliminary findings.     

Determination of bisphenol A using a flow injection inhibitory chemiluminescence method.

A new flow injection chemiluminescence (CL) method has been developed for the determination of bisphenol A (BPA), based on the inhibitory effect of BPA on the chemiluminescence reaction between luminol and potassium hexacyanoferrate. Under optimum conditions, the decrease in CL emission intensity was linear with BPA concentration in the range 8.0 x 10(-7)-1.2 x 10(-5) mol/L, and the detection limit was 3.1 x 10(-7) mol/L. The relative standard deviation (RSD) of 11 replicate measurements was 2.6% for 2.0 x 10(-6) mol/L BPA (n = 11). The sampling frequency was calculated to be ca. 120/h. This method has been successfully used to determine the content of BPA in aqueous solution of polycarbonate materials. A brief discussion on the possible chemiluminescence reaction mechanism is presented.     

Decontamination Activity of Ryegrass Exudates Towards Bisphenol A in the Absence and Presence of Dissolved Natural Organic Matter

Bisphenol A (BPA) is an endocrine disruptor compound widespread in terrestrial and aquatic systems of urbanized and industrialized regions. This study evaluated the capacity of ryegrass (Lolium perenne) aqueous exudates to degrade BPA at a concentration of 10 mg L^?1 both in the absence and in the presence of an organic fraction often coexisting with plant exudates, i.e., natural organic matter (NOM), tested at a concentration of 20 mg L^?1. In exudates alone, BPA degradation ceased after one day from the product addition when residual BPA resulted 65% of the initial BPA, whereas in exudates with the addition of NOM the degradation process continued for 4 days when residual BPA resulted 49%. Measurements of peroxidase and laccase activities in exudates suggested a significant involvement of these enzymes in BPA degradation. This finding was further confirmed by the almost complete absence of BPA degradation in aqueous exudates strongly acidified. In some BPA-contaminated exudates, chromatographic analysis revealed the presence of a newly formed compound identified as a BPA oxidation product by Fourier transform - ion cyclotron resonance mass spectrometry analysis. In conclusion, ryegrass exudates possess a relevant decontamination capacity towards BPA which persists and appears to be enhanced by the addition of NOM.     

Cytosolic NADPH may regulate differences in basal Nox oxidase-derived superoxide generation in bovine coronary and pulmonary arteries

Because systems controlled by basal NAD(P)H oxidase activity appear to contribute to differences in responses of endothelium-removed bovine coronary (BCA) and pulmonary (BPA) arteries to hypoxia, we characterized the Nox oxidases activities present in these vascular segments and how cytosolic NAD(P)H redox systems could be controlling oxidase activity. BPA generated approximately 60-80% more lucigenin (5 microM) chemiluminescence detectable superoxide than BCA. Apocynin (10 microM), a NAD(P)H oxidase inhibitor, and 6-aminonicotinamide (1 mM), a pentose phosphate inhibitor (PPP), both attenuated (approximately by 50-70%) superoxide detected in BPA and BCA. There was no significant difference in the expression of Nox2 or Nox4 mRNA or protein detected by Western blot analysis. NADPH and NADH increased superoxide in homogenates and isolated microsomal membrane fractions in a manner consistent with BPA and BCA having similar levels of oxidase activity. BPA had 4.2-fold higher levels of NADPH than BCA. The activity and protein levels of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting PPP enzyme generating cytosolic NADPH, were 1.5-fold higher in BPA than BCA. Thus BPA differ from BCA in that they have higher levels of G6PD activity, NADPH, and superoxide. Because both arteries have similar levels of Nox expression and activity, elevated levels of cytosolic NADPH may contribute to increased superoxide in BPA.     

Application of a novel mass spectrometric (MS) method to examine exposure to Bisphenol-A and common substitutes in a maternal fetal cohort

The use of Bisphenol A (BPA) has widely been replaced in consumer products by analogs BPB, BPE, BPF, BPS, and BPAF. Recent studies have linked these substitutes to similar adverse health outcomes as BPA, including disruption of endocrine pathways in animal and human studies. We designed a novel MS method, developed specifically for this study, to capture the most relevant BPA alternatives, BPB, BPE, BPF, BPS, BPAF and 4-NP in human blood and urine to quantify potential in utero exposures. To our knowledge, this is the first study to explore in utero exposure to these BPA analogs and the first U.S. study to test for BPA in maternal/fetal pairs. The method was run on 30 paired maternal urine and fetal cord blood samples from mothers undergoing elective Caesarean sections. 90% of mothers and 77% of babies tested positive for at least one BP analog. 83% of mothers tested positive for BPAF, 60% for BPS, 57% for BPB, 17% for BPF and 7% for BPA. 57% of babies tested positive for BPAF and 50% for BPF. BPA and BPB were detected in one cord blood sample each. BPS was not detected in cord blood. BPE was not detected in any fetal cord blood or maternal urine samples. These findings demonstrate the pervasiveness of some BP analogs in pregnant women and their babies at birth.     

The role of Bisphenol A in shaping the brain, epigenome and behavior

Bisphenol A (BPA) is a xenoestrogen that was first synthesized in 1891. Its estrogenic properties were discovered in 1930, and shortly after that chemists identified its usefulness in the production of epoxy resins. Since the 1950s BPA has been used as a synthetic monomer in the manufacturing of polycarbonate plastic, polystyrene resins, and dental sealants. Roughly 6.5 billion pounds of BPA are produced each year and it is the major estrogenic compound that leaches into nearby water and food supplies (vom Saal et al., 2007). BPA has been detected in 95% of human urine samples, which indicates that environmental exposure is widespread (Calafat et al., 2005). Moreover, BPA affects reproductive tissues and the brain. Thus many studies have focused on the effects of BPA during embryonic development. The most recent FDA update (Administration January 2010) points to “some concern about the potential effects of Bisphenol A on the brain, behavior, and prostate gland in fetuses, infants, and young children.” In light of this concern, we present an updated review of BPA's action on the brain and behavior. We begin with a discussion of BPA's role as both an endocrine active compound and an agent that alters DNA methylation. Next, we review publications that have reported effects of BPA on brain and behavior. We end with our interpretation of these data and suggestions for future research directions.     

Effect of probiotics, Bifidobacterium breve and Lactobacillus casei, on bisphenol A exposure in rats

Bisphenol A (BPA), a putative endocrine disruptor, may be taken up by humans via the diet and have adverse effects on human health. In this study, we evaluated whether the probiotics, Bifidobacterium breve strain Yakult (BbY) and Lactobacillus casei strain Shirota (LcS), could exert a protective effect against dietary exposure to BPA. A group of rats fed on a diet containing 5% BbY or 5% LcS showed three advantageous effects compared to the control group; (i) the area under the blood concentration-time curve of BPA after its oral administration was significantly decreased, (ii) the amount of BPA excreted in the feces was significantly greater (2.4 times), and (iii) the percentage of BPA bound to the sediment fraction of the feces was significantly higher. These results suggest that BbY and LcS reduced the intestinal absorption by facilitating the excretion of BPA, and that these probiotics may suppress the adverse effects of BPA on human health.     

双酚A与镉对植物光合作用的复合微生态效应

近年来,国内外学者研究了双酚A (BPA)及重金属镉(Cd)单一因子对植物光合作用的影响.但在自然背景下,污染多呈复合型,因此研究BPA和Cd对二者叠加的空间内植物光合作用的复合影响意义重大.本文综述了BPA对植物光合作用的影响及机制,及Cd对植物光合作用的影响及其机制,其中单一BPA和Cd对植物光合作用的影响均表现为:低浓度促进光合作用,高浓度反之.根据相关研究推测了植物在受到复合胁迫时的生态响应,相应的生理生化反应,及光合过程的响应机制.最后提出了BPA与Cd对植物复合胁迫可能开展的相关研究方向.     

Distribution of second generation European corn borer,Ostrinia nubilalis, egg masses in field corn and relationship to subsequent tunneling damage

The relationship between second generation European corn borer (Ostrinia nubilalis Hübner) egg mass numbers and subsequent field corn damage, as measured by stalk cavity numbers, was studied in 79 fields in northeastern North Carolina over three years. A mean of 0.028 egg masses per plant (645 egg masses/23400 plants) was found over the course of the study. Significant differences in oviposition rate were detected between fields and years. Ca. 85% of egg masses were deposited in a five leaf zone surrounding the primary ear; of these, 89% were found on the lower four leaves in this zone. Egg masses appeared to be distributed randomly within fields but at low rates of incidence, and oviposition was relatively uniform between sampling areas within individual fields. Under moderate to high oviposition pressure (mean number of egg masses per plant over the duration of the oviposition period >ca. 0.02), eggs laid during the early phases of the oviposition period account for more subsequent stalk damage than eggs laid during the later phases of the oviposition period. Variations in second generation egg mass numbers accounted for ca. 70% of variation in stalk cavity numbers.     

Into the world of steroids: A biochemical “keep in touch” in plants and animals

Evolution of steroids such as sex hormones and ecdysteroids occurred independently in the animal and plant kingdoms. Plants use phytoecdysteroids (PEs) to control defense interactions with some predators; furthermore, PEs can exert beneficial influence on many aspects of mammalian metabolism. Endocrine disrupting compounds such as the estrogen agonist bisphenol A (BPA) are widespread in the environment, posing a potential hormonal risk to animals and plants. Adverse BPA effects on reproductive development and function are coupled with other toxic effects. BPA bioremediation techniques could be developed by exploiting some tolerant plant species.Key words: androgens, endocrine disrupting compounds, bisphenol A, estrogens, hormone receptors, phytoecdysteroids     

Serum bisphenol a concentrations showed gender differences, possibly linked to androgen levels

To investigate human exposure to bisphenol A (BPA), a widely used endocrine disruptor, we measured serum BPA concentrations and analyzed the interrelation of BPA with sex-related hormones. BPA was detected in all human sera by a novel enzyme-linked immunosorbent assay. Serum BPA concentrations were significantly higher in normal men (1.49 +/- 0.11 ng/ml; P < 0.01) and in women with polycystic ovary syndrome (1.04 +/- 0.10 ng/ml; P < 0.05) compared with normal women (0.64 +/- 0.10 ng/ml). There were significant positive correlations between serum BPA and total testosterone (r = 0.595, P < 0.001) and free testosterone (r = 0.609, P < 0.001) concentrations in all subjects and likewise between serum BPA and total testosterone (r = 0.559, P < 0.01) and free testosterone (r = 0.598, P < 0.001) concentrations in all female subjects, but not between serum BPA and other sex-related hormone concentrations in any group. These findings showed that there are gender differences in serum BPA concentrations, possibly due to differences in the androgen-related metabolism of BPA.     

Adsorption of bisphenol A by lactic acid bacteria,Lactococcus, strains

Ten strains of the genus Lactococcus were examined for their ability to remove bisphenol A [2, 2-bis(4-hydroxyphenyl)propane; BPA], which is known as an endocrine disrupter. Nine strains of the lactococci tested could remove BPA from media during growth, although the removal ratio was below 9%. When BPA was incubated with lyophilized cells of lactococci for 1 h, the concentration of BPA in the media was decreased by 9–62%. Especially, the highest removal ratio of BPA was observed for Lactococcus lactis subsp. lactis 712. The lactococci could adsorb BPA but not degrade it, because the lactococci maintained the ability to remove BPA from the medium after autoclaving. When the lyophilized cells of L. lactis subsp. lactis 712 were also incubated with six analogues of BPA, they effectively adsorbed hydrophobic compounds such as 2, 2′-diphenylpropane and bisphenol A dimethylether. The BPA-adsorbing ability of lactococci could be due to the hydrophobic binding effect. The removal ratio of BPA by L. lactis subsp. lactis 712 was increased after treatment with sodium dodecyl sulfate and decreased after digestion with trypsin. These results suggest that the hydrophobic proteins on cell surface may be involved in the BPA-adsorbing ability of lactococci.     

The environmental endocrine disruptor, bisphenol A, affects germination, elicits stress response and alters steroid hormone production in kiwifruit pollen

In vitro toxicity of the endocrine disruptor bisphenol A (BPA) to pollen, the male haploid generation of higher plants, was studied. BPA caused significant inhibition of both tube emergence and elongation of kiwifruit pollen in a dose-dependent manner, beginning at 10 mg · l(-1); morphological changes to tubes were also detected. Despite strong inhibition of pollen tube production and growth, a large percentage of treated cells remained viable. Immunoblotting experiments indicated that levels of BiP and 14-3-3, which are proteins involved in stress response, substantially increased in BPA-treated pollen compared to controls. The increases were dose-dependent in the range 10-50 mg · l(-1) BPA, i.e. even when germination ability was completely blocked. Steroid hormones (17 β-estradiol, progesterone and testosterone) were detected in kiwifruit pollen, and their levels increased during germination in basal medium. In a BPA treatment of 30 mg · l(-1), larger increases in both estrogen and testosterone concentrations were detected, in particular, a six-fold increase of 17 β-estradiol over control concentration (30 min). The increased hormone levels were maintained for at least the 90 min incubation. Increasing concentrations of exogenous testosterone and 17 β-estradiol increasingly inhibited pollen tube emergence and elongation. Current data for BPA-exposed kiwifruit pollen suggest a toxicity mechanism that is at least in part based on a dramatic imbalance of steroid hormone production during tube organisation, emergence and elongation. It may be concluded that BPA, a widespread environmental contaminant, can cause serious adverse effects to essential pollen functions. On a broader scale, this chemical poses a potential risk to the reproductive success of higher plants.     

Degradation of bisphenol A by the lignin-degrading enzyme, manganese peroxidase, produced by the white-rot basidiomycete, Pleurotus ostreatus

Degradation of 2,2-Bis(4-hydroxyphenyl)propane (bisphenol A, BPA), an endocrine-disturbing chemical, by the growing mycelia of the white-rot basidiomycete, Pleurotus ostreatus, was examined. About 80% of BPA initially present decreased in 12 days of culture with this fungus. By in vitro experiments using the lignin-degrading enzyme manganese peroxidase (MnP), BPA was metabolized to phenol, 4-isopropenylphenol, 4-isopropylphenol, and hexestrol. The degradation products of BPA were assumed to be formed by the one-electron oxidation of the substrate.     

Sensitive method for the determination of bisphenol-A in serum using two systems of high-performance liquid chromatography

The aim of this study was to establish an easy and accurate method for the determination of bisphenol-A (BPA) in the body liquid such as serum and urine. Two high-performance liquid chromatography (HPLC) systems, HPLC with electrochemical detector (ED), and HPLC with mass spectrometry (MS) using electrospray ionization (ESI) interface were used for the assay in the serum samples prepared with solid-phase extraction method. Water or EtOH at a concentration below 50% was suitable for the extraction of BPA from serum. The limit of detection of BPA was 0.2 ng ml⁻¹ for the HPLC-ED method and 0.1 ng ml⁻¹ for HPLC–MS. There was a good correlation between the data obtained by the two HPLC systems. BPA concentrations in healthy human serum were low (0–1.6 ng ml⁻¹). From various commercial fetal bovine serum and sheep plasma, however, significant amounts of BPA were detected. Since no BPA was detected from sheep plasma immediately after collection, the high amounts of BPA were considered to be caused by the handling of blood during the preparation of the products after blood collection. In vitro study showed that the amount of BPA leached from polycarbonate tube into sheep plasma were 40 times larger than those into water and the leached amount of BPA depended on the temperature (37°C>20°C>5°C).     

Secondary metabolite content in rhizomes, callus cultures and in vitro regenerated plantlets of Solidago chilensis

An in vitro culture system leading to the formation of callus and plant regeneration, starting from nodal sections and shoot tips, was developed for Solidago chilensis (Asteraceae). The content of the gastroprotective diterpene solidagenone as well as the phenolics chlorogenic acid (CA) and rutin was determined either in rhizomes from wild growing plants and in callus and in in vitro regenerated plantlets by analytical HPLC. Additionally, total phenolic and flavonoid content was assessed in plant samples, callus and cell suspensions. In terms of dry starting material, the percentual solidagenone content in nine S. chilensis samples ranged from 0.5-3.5% for rhizomes from wild growing plants, 0.1-0.3% for callus and 0.3% for an in vitro regenerated plantlet, respectively. The highest solidagenone contents were found in the wild plant during the late summer in the months of March and April (3.5-2.2%) while highest values for chlorogenic acid (0.5%) and rutin (0.4%) were detected in May, before senescence. The callus tissue and cell suspensions contained some 1.8-2.0 and 1.2% of total phenolics, respectively. CA was the main phenolic in the cell suspension while only traces were found in the callus. Rutin was not detected in the callus nor cell culture.     

Purification of cytochrome P450 and ferredoxin, involved in bisphenol A degradation, from Sphingomonas sp. strain AO1

In a previous study (M. Sasaki, J. Maki, K. Oshiman, Y. Matsumura, and T. Tsuchido, Biodegradation 16:449-459, 2005), the cytochrome P450 monooxygenase system was shown to be involved in bisphenol A (BPA) degradation by Sphingomonas sp. strain AO1. In the present investigation, we purified the components of this monooxygenase, cytochrome P450 (P450bisd), ferredoxin (Fd(bisd)), and ferredoxin reductase (Red(bisd)). We demonstrated that P450bisd and Fd(bisd) are homodimeric proteins with molecular masses of 102.3 and 19.1 kDa, respectively, by gel filtration chromatography analysis. Spectroscopic analysis of Fd(bisd) revealed the presence of a putidaredoxin-type [2Fe-2S] cluster. P450(bisd), in the presence of Fd(bisd), Red(bisd), and NADH, was able to convert BPA. The K(m) and kcat values for BPA degradation were 85 +/- 4.7 microM and 3.9 +/- 0.04 min(-1), respectively. NADPH, spinach ferredoxin, and spinach ferredoxin reductase resulted in weak monooxygenase activity. These results indicated that the electron transport system of P450bisd might exhibit strict specificity. Two BPA degradation products of the P450(bisd) system were detected by high-performance liquid chromatography analysis and were thought to be 1,2-bis(4-hydroxyphenyl)-2-propanol and 2,2-bis(4-hydroxyphenyl)-1-propanol based on mass spectrometry-mass spectrometry analysis. This is the first report demonstrating that the cytochrome P450 monooxygenase system in bacteria is involved in BPA degradation.