Protective effects of polyphenols against endocrine disrupting chemicals

Food Science and Biotechnology - Endocrine disrupting chemicals (EDCs) are a heterogenous group of compounds dispersed throughout the environment that possess the ability to alter endocrine system...     

食品中酚类内分泌干扰物的研究进展

壬基酚、辛基酚和双酚A等以其相似的结构特征和类雌激素效应被称为酚类内分泌干扰物,它们在食品包装材料及食品中的残留已引起了人们的广泛关注。本文以食品中的酚类内分泌干扰物为重点,对壬基酚、辛基酚和双酚A的性质、应用、毒性以及在食品中的污染水平、主要来源和分析测定方法等进行了评述,为我国开展食品领域内酚类内分泌干扰物的限量制定和研究提供参考。      

Sorption of selected endocrine disrupting chemicals to different aquatic colloids

The sorption of seven endocrine disrupting chemicals (EDCs) to aquatic colloids was determined by cross-flow ultrafiltration (CFUF) followed by gas chromatography-mass spectrometry (GC-MS). Results show that the colloidal organic carbon normalized sorption coefficient (Kcoc) of EDCs to different aquatic colloids varies by a factor of 6-12 because such colloids are of different origin. Through characterization of colloidal samples, a significant relationship was established between Kcoc values and the molar extinction coefficient of colloids at 280 nm, whereas no other colloidal properties such as elemental ratios were correlated with Kcoc values. The results are consistent with other reports of the importance of the quality of sorbents such as their aromatic carbon content in sorbing various organic pollutants. The presence of a surfactant was found to increase Kcoc values for estrone (El) and 17alpha-ethynylestradiol (EE2). The method was subsequently applied for determining EDC concentrations in field samples, where both conventional and truly dissolved EDCs showed higher concentrations close to sewage outfalls than either upstream or downstream, confirming the sourceconcentration relationship. In addition, the truly dissolved EDC concentrations were lower than the conventional dissolved concentrations, confirming that there were interactions between aquatic colloids and EDCs. It is estimated that between 10 and 29% of EDCs are associated with aquatic colloids. As colloids are highly abundant in rivers and ocean, they will therefore play a significant role in the environmental behavior and fate of EDCs.     

珠江八大河口表层沉积物中典型环境 内分泌干扰物的分布特征

目的 本研究旨在研究珠江八大河口表层沉积物中七种典型环境内分泌干扰物(EDCs)的分布特征。 方法 本研究采集了八大口门的表层沉积物,采用加速溶剂萃取-衍生化-气相色谱质谱技术分析了七种典型EDCs含量。结果 化工类化合物壬基酚(NP)、双酚A(BPA)、四羟基苯甲酸丙酯(PP)和辛基酚(OP),甾醇类自然雌激素雌二醇(E2)、雌酮(E1)和合成雌激素乙炔雌二醇(EE2)均有检出。除EE2的检出率为88.2%,其余EDCs的检出率为100%,其浓度范围(ng.g_-1 dw)从大到小依次为：NP (565.28-812.6) > BPA (42.55-248.25) > PP (93.44-109.96) > OP (3.62-11.52)、E1 (14.13-23.13)、E2 (6.86-15.42)、EE2 (ND-4.2-23.45)。结论 四种化工类EDCs和EE2在八个河口中的分布特征类似,东四河口的浓度累积量明显高于西四河口,且其中的虎门河口浓度较高。在各河口中EDCs浓度表现出从河道至河口外方向随水流逐渐降低。E1和E2在除鸡啼门外的其他七个河口中的不同采样点处的浓度变化不大,鸡啼门中有可能的点污染源。     

核酸适配体生物传感器用于内分泌干扰物快速检测研究进展

内分泌干扰物是一种外源性化学物质, 食物是人体摄入这些化学物的主要来源,当人体摄入受到环境或食物接触材料污染的食物,其中的内分泌干扰化学物很容易进入人体并蓄积,能在不同程度上干扰内源性激素系统, 导致不良健康影响 。因此对其进行便捷、高效、灵敏、快速检测尤为必要。目前常通过气相色谱法及其他仪器方法对其进行检测, 然而这些方法耗时费力且成本高昂, 难以满足现场快速检测的要求。适配体是通过体外指数富集的的配基系统进化技术(systematic evolution of ligands by exponential enrichment, SELEX) 策略系统筛选出的单链寡核苷酸分子, 具有易合成、易修饰、性质稳定、特异性好和亲和常数高等优势, 已广泛应用于生物传感检测方法的构建。基于适配体识别的电化学或光学的内分泌干扰物快速检测方法具有使用简便、响应快速、便于现场筛查使用的优势, 可以与实验室精准检测技术优势互补, 具有重要的研究和应用意义。本文综述了近年来基于适配体识别构建的电化学、光学传感器在对水样、食品、塑料制品、生物样本中 内分泌干扰物快速检测的研究进展, 总结了该领域面临的挑战和发展方向 , 为适配体传感检测技术在内分泌干扰物识别深入研究提供参考。     

食源性内分泌干扰物联合效应研究进展

食源性内分泌干扰物(endocrine disrupting chemicals,EDCs)因具有相似的作用终点,低剂量下混合暴露可能产生大于单一暴露的联合效应,已成为影响食品安全的一类重要风险因子,国际上已开始关注低剂量下混合暴露所引起的联合效应问题。本文首先对食源性EDCs的污染现状和检测技术(包括前处理技术和高通量检测技术)进行了梳理分析,基于气相色谱-质谱、液相色谱-质谱的分析技术已经成为EDCs的主流分析技术。随后,探讨了模式生物和毒性替代测试在联合效应研究中的研究现状,最后从浓度相加模型、独立作用模型和相互作用模型等3个方面介绍了联合效应评价方法的研究进展。基于毒性测试替代技术的联合效应研究将为科学评价食源性EDCs的联合效应,揭示联合效应产生的分子机制,修订食源性EDCs的安全限量标准提供依据。     

Oxidation of phenolic endocrine disrupting chemicals by potassium permanganate in synthetic and real waters

In this study, five selected environmentally relevant phenolic endocrine disrupting chemicals (EDCs), estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, and 4-n-nonylphenol, were shown to exhibit similarly appreciable reactivity toward potassium permanganate [Mn(VII)] with a second-order rate constant at near neutral pH comparable to those of ferrate(VI) and chlorine but much lower than that of ozone. In comparison with these oxidants, however, Mn(VII) was much more effective for the oxidative removal of these EDCs in real waters, mainly due to the relatively high stability of Mn(VII) therein. Mn(VII) concentrations at low micromolar range were determined by an ABTS [2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid diammonium] spectrophotometric method based on the stoichiometric reaction of Mn(VII) with ABTS [Mn(VII) + 5ABTS → Mn(II) + 5ABTS(?+)] forming a stable green radical cation (ABTS(?+)). Identification of oxidation products suggested the initial attack of Mn(VII) at the hydroxyl group in the aromatic ring of EDCs, leading to a series of quinone-like and ring-opening products. The background matrices of real waters as well as selected model ligands including phosphate, pyrophosphate, NTA, and humic acid were found to accelerate the oxidation dynamics of these EDCs by Mn(VII). This was explained by the effect of in situ formed dissolved Mn(III), which could readily oxidize these EDCs but would disproportionate spontaneously without stabilizing agents.     

Understanding ligninase-mediated reactions of endocrine disrupting chemicals in water: reaction rates and quantitative structure-activity relationships

We have verified in our previous work that lignin peroxidase (LiP) mediates effective removal of selected natural and synthetic estrogens. The efficiency of these reactions was greatly enhanced in the presence of veratryl alcohol (VA), a chemical that is produced along with LiP by certain white rot fungi, for example, Phanerochaete chrysosporium. In this study, we systematically evaluated the kinetic behaviors of LiP-mediated reactions for six endocrine disrupting compounds (EDCs), that is, steroid estrogens and their structural analogs, in both the presence and absence of VA. Resulting kinetic parameters were then correlated with structural features of LiP/substrate binding complexes, as quantified using molecular simulation, to create quantitative structure-activity relationship (QSAR) equations. These equations suggest that binding distance between a substrate's phenolic proton and δN of HIS47's imidazole ring plays an important role in modulating substrate reactivity toward LiP in both the presence and absence of VA. This information provides insight into an important enzymatic reaction process that occurs in the natural environment affecting EDC transformation, a process that may be used in engineered systems to achieve EDC removal from water.     

Isomer-specific degradation and endocrine disrupting activity of nonylphenols

Degradation of technical nonylphenol by Sphingobium xenophagum Bayram led to a significant shift in the isomers composition of the mixture. By means of gas chromatography-mass spectrometry, we could observe a strong correlation between transformation of individual isomers and their alpha-substitution pattern, as expressed by their assignment to one of six mass spectrometric groups. As a rule, isomers with less bulkiness at the alpha-carbon and those with an optimally sized main alkyl chain (4-6 carbon atoms) were degraded more efficiently. By mass spectrometric analysis, we identified the two most recalcitrant main isomers of the technical mixture (Group 4) as 4-(1,2-dimethyl-1-propylbutyl)phenols (NP193a and NP193b), which are diastereomers with a bulky alpha-CH3, alpha-CH(CH3)C2H5 substitution. Our experiments with strain Bayram show that the selective enrichment of isomers with bulky alpha-substitutions observed in nonylphenol fingerprints of natural systems can be caused by microbial ipso-hydroxylation. Based on the yeast estrogen assay (YES), we established an estrogenicity ranking with a variety of single isomers and compared it to rankings obtained with different reporter cell systems. Structure-activity relationships derived from these data suggest that Group 4 isomers have a high estrogenic potency. This indicates a substantial risk that enrichment of highly estrogenic isomers during microbial degradation by ipso-substitution will increase the specific estrogenicity of aging material.     

Degradation of endocrine disrupting chemicals bisphenol A, ethinyl estradiol, and estradiol during UV photolysis and advanced oxidation processes

The degradation of three endocrine disrupting chemicals (EDCs), bisphenol A, ethinyl estradiol, and estradiol, was investigated via ultraviolet (UV) radiation photolysis and the UV/hydrogen peroxide advanced oxidation process (AOP). These EDCs have been detected at low levels in wastewaters and surface waters in both the United States and European countries, can cause adverse effects on humans and wildlife via interactions with the endocrine system, and thus must be treated before entering the public drinking water supply. Because many EDCs can only be partially removed with conventional water treatment systems, there is a need to evaluate alternative treatment processes. For each EDC tested, direct UV photolysis quantum yields were derived for use with both monochromatic low-pressure (LP) UV lamps and polychromatic medium-pressure (MP) UV lamps and second-order hydroxyl radical rate constants were developed. These parameters were utilized to successfully model UV treatment of the EDCs in laboratory and natural waters. The polychromatic MP UV radiation source was more effective for direct photolysis degradation as compared to conventional LP UV lamps emitting monochromatic UV 254 nm radiation. However, in all cases the EDCs were more effectively degraded utilizing UV/H2O2 advanced oxidation as compared to direct UV photolysis treatment.     

Fate of endocrine disrupting compounds in membrane bioreactor systems

Yeast estrogen screen (YES) bioassay and liquid chromatography-mass spectrum-mass spectrum (LC-MS-MS) analysis were performed to investigate the fate of active and potential endocrine disrupting compounds in 3 pilot-scale and 2 lab-scale membrane bioreactor (MBR) systems. Compared with the overall estrogenicities of sewage treatment plant (STP) effluents from references, the MBR systems studied have relatively good performance in the removal of estrogenicity. Estrone (E1) was removed with relatively high efficiency (80.2-91.4%), but 17beta-estradiol (E2) was removed with moderate efficiency (49.3-66.5%) by the MBRs. However, the experimental results indicated that after the treatment by MBR, substantial amounts of E1, estrone-3-sulfate (E1-3S), estrone-3-glucuronide (E1-3G), and 17beta-estradiol-glucuronides (E2-G) passed through treatment systems and entered into the aquatic environment. The reduction in the levels of overall equivalent E1 (68.4%) and that of overall equivalent E2 (80.8%) was demonstrated for the pilot-scale MBR-B. For alkylphenol compounds, bisphenol A (BPA) was removed well with a removal efficiency of 68.9 -90.1%, but 4-nonylphenol (4-NP) concentration was amplified (removal efficiency of -439.5 to -161.1%) after MBR treatment which could be caused by the transformation of its parent compounds, nonylphenol polyethoxylates (NPnEOs). The amounts of adsorbed estrogens per kg dry mass was relatively low, due to short hydraulic retention time and high mixed liquor suspended solids in MBRs, compared to that in STPs.     

Assessing nitrogen and phosphorus efficiency at farm and catchment scale using nutrient budgets

Farm nutrient budgets related to 1994 were calculated for seven farm types, accounting for ∼90% of the agricultural land in the River Ythan catchment, NE Scotland. The magnitude of fluxes of nitrogen (N) and phosphorus (P) at the catchment scale in relation to these farm types was also assessed. Positive budgets were calculated for all farm types, with the largest surpluses estimated for intensive livestock units. Nutrient efficiency, defined as a percentage of outgoing over incoming nutrients, ranged from 11% (N) and 21% (P) on ‘cattle and sheep’ farms in less favoured areas to 54% (both N and P) on ‘cereal’ farms. The contribution from cropping versus livestock farming in the total efficiency varied widely between farm types. At the catchment scale the surplus associated with grassland and livestock (225 and 37 kg ha⁻¹ of N and P) clearly exceeded that associated with arable crops (44 and 19 kg ha⁻¹ of N and P). © 2000 Society of Chemical Industry     

Global gene expression profiling in larval zebrafish exposed to microcystin-LR and microcystis reveals endocrine disrupting effects of Cyanobacteria

Microcystis blooms occur worldwide and threaten aquatic ecosystems and human health. Sublethal effects on early developmental stages of fish are largely unknown, and research has mainly focused on microcystin toxins (such as MC-LR) rather than Microcystis cells. We exposed (96 h) zebrafish larvae to purified MC-LR (0-1000 μg/L) or lyophilized Microcystis aeruginosa containing 4.5 μg/L MC-LR and evaluated changes in global gene expression (Affymetrix GeneChip zebrafish genome arrays). Significant changes in gene expression (≥ 1.7-fold change, p < 0.0001) were determined with Rosetta Resolver 7.0, and ontology analysis was conducted with the DAVID bioinformatics tool. The number of differentially expressed genes relative to control increased with MC-LR concentration and included genes related to known mechanisms of action for MC-LR in mammals and older life stages of fish, as well as genes unique to larval zebrafish. Up-regulation of vitellogenin genes (vtg) (19.2-fold to >100-fold on arrays; 619.3-fold confirmed by quantitative PCR) was observed in Microcystis-exposed larvae but not in larvae exposed to MC-LR. Up-regulation of vtg indicates exposure to estrogenic substance(s) and suggests that Microcystis may be a natural source of environmental estrogens. Concerns about effects of Microcystis blooms may extend beyond those associated with the microcystin toxin.     

Quantifying diffuse and point inputs of perfluoroalkyl acids in a nonindustrial river catchment

Recently, the role of diffuse inputs of perfluoroalkyl acids (PFAAs) into surface waters has been investigated. It has been observed that river loads increased during rain and that street runoff contained considerable loads of PFAAs. This study aims at quantifying these diffuse inputs and identifying the initial sources in a small nonindustrial river catchment. The river was sampled in three distinct subcatchments (rural, urban, and wastewater treatment plant) at high temporal resolution during two rain events and samples were analyzed for perfluorocarboxylates and perfluorosulfonates. Additionally, rain, stormwater runoff, wastewater effluent, and drinking water were sampled. PFAA concentrations in river water were all low (e.g., < 10 ng/L for perfluorooctanoate, PFOA), but increased during rainfall. PFAA concentrations and water discharge data were integrated into a mass balance assessment that shows that 30-60% of PFAA loads can be attributed to diffuse inputs. Rain contributed 10-50% of the overall loads, mobilization of dry deposition and outdoor release of PFAA from products with 20-60%. We estimated that within a year 2.5-5 g of PFOA originating from rain and surface runoff are emitted into this small catchment (6 km(2), 12,500 persons).     

Subtoxic effects of certain chemicals on food crops

An increased supply of food is urgently needed to provide adequate nutrients to the increasing world population. Plant foods are basic in the nutrition of man. Increasing the productivity and efficiency of plant foods is, therefore, essential. Application of low concentrations of certain chemicals have helped in making a breakthrough in this direction. Certain chemicals are known to stimulate plant growth and yield. Many growth regulators also increase the protein content of plants. Treatment with pesticides and herbicides may also change the nutritive quality. These effects have been explored in detail for specific food crops and individual chemicals and the findings are presented here. It should be noted, however, that most of these findings are of an experimental nature and their practical application will depend upon the discovery of more powerful chemicals and further research into less expensive ways to use them with fewer side effects.     

在纳米尺度控制3D结构获得复合补偿效应

日本大阪东丽工业公司开发的新型纳米整理技术,将两种以上的功能材料混合形成纳米尺度的3D结构,能够获得复合补偿效应.这项技术由于能获得各种类型的3D结构,从而能扩大复合补偿效应.     

Economic and phosphorus-related effects of precision feeding and forage management at a farm scale

Structural best management practices were implemented throughout the Cannonsville Reservoir Watershed (CRW) in an effort to reduce P losses to the reservoir. Yet long-term water quality control efforts within CRW are hindered by continuous P build-up in the soils resulting from dairy farm P imports exceeding exports. Addressing the P imbalance problems and maintaining economic viability of the farms requires a system-level redesign of farm management. One possible innovative strategy, precision feed management (PFM), reduces soil-P build-up by limiting feed and fertilizer purchases, and increasing high-quality homegrown forage production. This study applied the integrated farm system model (IFSM) to 2 CRW dairy farms to quantify the benefits of a PFM farm planning strategy in controlling P imbalance problems, and maintaining farm profit-ability and reducing off-farm P losses. The IFSM accurately simulated the 2 farms based on farm data supplied by farm planners; these scenarios were used as the baseline conditions. The IFSM simulations of more accurate feeding of P (based on P required in animal diets) integrated with increased productivity of grass-forage and increased proportion of forage in the diet reduced the P imbalance of 1 farm from 5.3 to 0.5 kg/ha and from 9.6 to 0.0 kg/ha for the second farm. For both farms, soluble P lost to the environment was reduced by 18%. Feed supplement purchases declined by 7.5 kg/cow per year for dietary mineral P, and by 1.04 and 1.29 t/cow per year for protein concentrates through adoption of the PFM system. Moreover, when a land management practice of converting corn to grass was coupled with the precision feeding of P and improved forage management, IFSM predicted reductions of 5.8 and 9.3 kg/ha of converted land sediment-bound P in erosion loss each year. The model predicted slight purchase increases in corn grain to offset reductions in corn silage production and feeding rates, but no appreciable change in the farm P balance due to land conversion. The model-based studies conducted on a farm-by-farm basis complement farm planning efforts in exploring innovative farming systems. Moreover, the results set a benchmark for potential benefits of PFM strategies, economically and environmentally.     

我国皮化工业现状及国内外皮化材料的发展趋势

综述了我国皮化工业现状及国内外皮化材料的发展趋势 ,并总结了汽车座垫革和所用皮化材料的研究情况。     

Something from "nothing"--eight weak estrogenic chemicals combined at concentrations below NOECs produce significant mixture effects

We tested whether multicomponent mixtures of xenoestrogens would produce significant effects when each component was combined at concentrations below its individual NOEC or EC01 level. The estrogenic effects of eight chemicals of environmental relevance, including hydroxylated PCBs, benzophenones, parabenes, bisphenol A, and genistein, were recorded using a recombinant yeast estrogen screen (YES). To ensure that no chemical contributed disproportionately to the overall combination effect, a mixture was prepared at a mixture ratio proportional to the potency of each individual component. The performance of four approaches for the calculation of additive combination effects (concentration addition, toxicity equivalency factors, effect summation, and independent action) was compared. Experimental testing of the predictions revealed that concentration addition and its application, the toxicity equivalency factor approach, were valid methods for the calculation of additive mixture effects. There was excellent agreement between prediction and observation. In contrast, independent action and effect summation led to clear underestimations of the experimentally observed responses. Crucially, there were substantial mixture effects even though each chemical was present at levels well below its NOEC and EC01. We conclude that estrogenic agents are able to act together to produce significant effects when combined at concentrations below their NOECs. Our results highlight the limitations of the traditional focus on the effects of single agents. Hazard assessments that ignore the possibility of joint action of estrogenic chemicals will almost certainly lead to significant underestimations of risk.