Atmospheric and riverine inputs of metals,nutrients and persistent organic pollutants into the lagoon of Venice

Atmospheric deposition in the lagoon of Venice and river inputs from the watershed were collected and analysed from 1998 to 1999 using the same analytical methods. The input from riverine sources largely prevails (>70%) over that from the atmosphere for As, Cr, Fe, Mn, Ni, nitrogen and phosphorus. Equivalent amounts of Hg, Pb, PCBs, HCB are discharged into the lagoon from the two sources, whilst atmospheric inputs prevail for Cd, ammonia and dioxins. A comparison with figures of maximum allowable discharges (MAD) for various compounds, recently set by the Italian Ministry for the Environment, showed that total inputs (riverine + atmospheric) of trace metals were below the MAD thresholds only for Cr, Cu, Ni and Zn. The total inputs of Cu and Ni, and Cr and Zn were approximately 20 and 40% of the MAD limit, respectively. The total phosphorus input of 284 t was close to the imposed limit, whilst the inorganic nitrogen load alone (>4000 t) was much higher than the MAD for total nitrogen. For those metals (As, Cd, Hg and Pb) and persistent organic pollutants, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) where the MAD states that the load should tend to ‘0’ (no discharge), the measured inputs of 4.8 (As) and 5.1 t (Pb), 151 (Cd) and 39 kg (Hg), 18 g (PCDD/Fs) and 440 mg (Toxicity Equivalents, TEQs, of PCDD/Fs) are by definition ‘above’ the MAD. The principal component analysis (PCA) of loading data and input profiles (markers) of production typologies showed that river and atmosphere contributions can be easily separated and recognised due to their different fingerprints. Riverine inputs were similar to chemical and glass work production markers, whereas atmospheric loadings were mainly influenced by chemical industry (PVC and VCM production), metallurgy and paper-mill.     

Removal of persistent organic pollutants from micro-polluted drinking water by triolein embedded absorbent

A new biomimetic absorbent, cellulose acetate (CA) embedded with triolein (CA-triolein), was prepared and applied for the removal of persistent organic pollutants (POPs) from micro-polluted aqueous solution. The comparison of CA-triolein, CA and granular activated carbon (GAC) for dieldrin removal was investigated. Results showed that CA-triolein absorbent gave a lowest residual concentration after 24 h although GAC had high removal rate in the first 4 h adsorption. Then the removal efficiency of mixed POPs (e.g. aldrin, dieldrin, endrin and heptachlor epoxide), absorption isotherm, absorbent regeneration and initial column experiments of CA-triolein were studied in detail. The linear absorption isotherm and the independent absorption in binary isotherm indicated that the selected POPs are mainly absorbed onto CA-triolein absorbent by a partition mechanism. The absorption constant, K, was closely related to the hydrophobic property of the compound. Thermodynamic calculations showed that the absorption was spontaneous, with a high affinity and the absorption was an endothermic reaction. Rinsing with hexane the CA-triolein absorbent can be regenerated after absorption of POPs. No significant decrease in the dieldrin removal efficiency was observed even when the absorption–regeneration process was repeated for five times. The results of initial column experiments showed that the CA-triolein absorbent did not reach the breakthrough point at a breakthrough empty-bed volume (BV) of 3200 when the influent concentration was 1–1.5 μg/L and the empty-bed contact time (EBCT) was 20 min.     

DNA methyltransferase inhibitor assay system based on the HBx-induced DNA methylation of E-cadherin

We here report a simple assay system for DNA methyltransferase (DNMT) inhibitors based on the HBx-induced DNA methylation of E-cadherin. A stable cell line named G1 was generated by co-transfecting E-cadherin luciferase reporter and HBx-expression plasmid into HepG2 cells. Treatment of G1 cells with DNMT inhibitors, 5-azacytidine, 5-aza-2′-deoxycytidine, and procainamaid, dose-dependently inhibited DNA methylation of E-cadherin promoter in the reporter, resulting in up-regulation of luciferase levels and its enzyme activity. Treatment with all-trans retinoic acid that is known to inhibit DNMT expression, also induced similar effects. Our system can be useful for development of epi-drugs targeting DNA methylation in malignancies.     

E-cadherin gene promoter hypermethylation in H. pylori-induced enlarged fold gastritis

BACKGROUND: Promoter hypermethylation of E-cadherin plays an important role on gastric carcinogenesis. We have previously reported that the odds ratio for gastric carcinoma and the prevalence of diffuse-type early gastric carcinoma in Helicobacter pylori-induced enlarged fold gastritis increased with increasing fold width. Thus, we examined E-cadherin methylation in gastric mucosa from H. pylori-induced enlarged fold gastritis before and after H. pylori eradication. Moreover, we analyzed the mechanism of H. pylori infection-induced E-cadherin hypermethylation. MATERIALS AND METHODS: Twenty-three H. pylori-positive patients with enlarged folds, 18 H. pylori-positive and seven H. pylori-negative patients without enlarged folds, were involved in the study. E-cadherin promoter methylation was studied using quantitative methylation-specific polymerase chain reaction. We investigated methylation percentage and DNA methyltransferase activity in gastric cancer cell lines treated with EGF, TNFalpha, and MG132. RESULTS: E-cadherin methylation percentage of the gastric antral and body mucosa in H. pylori-positive patients with enlarged folds was much greater than that in both H. pylori-positive and -negative patients without enlarged folds. After H. pylori eradication, the methylation percentage in six patients with enlarged fold gastritis decreased significantly from 15.6 +/- 3.9 to 8.8 +/- 2.2 (p < .05). Moreover, the methylation was induced by TNFalpha, MG132, and EGF treatment, and DNA methyltransferase activity was induced by EGF treatment in MKN-1 cells. CONCLUSIONS: Our findings suggest that the hypermethylation of E-cadherin promoter might be involved in the process of gastric carcinoma through the specialized factors in H. pylori-induced enlarged fold gastritis.     

Hepatitis C virus represses E-cadherin expression via DNA methylation to induce epithelial to mesenchymal transition in human hepatocytes

Hepatitis C virus (HCV) core protein is known to induce promoter hypermethylation of tumor suppressor genes including E-cadherin to repress their expression when overexpressed in human hepatocytes; however, its actual role during HCV infection is still unknown. Here, we report that infection with HCV derived from pJFH-1 replicon system that mimics natural infection elevates protein levels of DNA methyltransferase 1 and 3b to enhance DNMT activity in human hepatocytes. As a consequence, HCV induced promoter hypermethylation of E-cadherin, resulting in repression of its expression. In addition down-regulation of E-cadherin by HCV led to epithelial–mesenchymal transition that is known to be a critical event during the late stage of tumorigenesis.     

Harnessing plant-bacteria-fungi interactions to improve plant growth and degradation of organic pollutants

Exploiting the potential of bacteria in phytoremediation for the removal of organic and inorganic pollutants from soils and (ground)water holds great promise. Besides bacteria, mycorrhizal fungi and free-living saprotrophs are well known for their strong degradative capacities and plant growth promotion effects, which makes them of high interest for use in different bioremediation strategies. To further increase the efficiency and successes of phytoremediation, interactions between plants and their associated microorganisms, both bacteria and fungi, should be further investigated, in addition to the close interactions between bacteria and fungi. Benefitting from an increased understanding of microbial community structure and assembly allows us to better understand how the holobiont can be modified to improve pollutant degradation and plant growth. In this review, we present an overview of insights in plant-bacteria-fungi interactions and the opportunities of exploiting these tripartite interactions to enhance the effectiveness of phytoremediation of organic pollutants.     

E-cadherin promoter methylation can regulate its expression in invasive ductal breast cancer tissue in Chinese woman

Promoter methylation is an important mechanism of regulating E-cadherin expression. Methylation-specific PCR (MSP) assay was done to evaluate the promoter methylation status of E-cadherin gene in primary tumor samples from 23 cases of Chinese women with invasive ductal breast cancers. Western blotting assay was employed for E-cadherin and beta-actin expressions. Positive MSP results occurred in 26.1% (6/23) of primary tumor samples and none of four normal skin samples. These molecular events tended to occur in breast cancers associated with poor prognosis. Whereas the mean ratio of CDH1/beta-actin for six MSP-positive cases was 0.0290 +/- 0.0355, the mean ratio for 17 MSP-negative cases was 0.4726 +/- 0.5049 (P = 0.046). In conclusion, aberrant E-cadherin methylation preferentially occurs in invasive ductal breast cancer associated with poor prognosis and is one of the mechanisms of E-cadherin expression silence in breast cancers from Chinese women.     

有机污染物在表层土壤中光降解的研究进展

土壤是承载有机污染物的重要介质,而光降解是降解土壤表层有机污染物的一种非常重要的非生物转化途径。研究土壤表层有机物的光降解对认识污染物土壤环境行为有非常重要的意义。20世纪90年代以来对土壤中有机污染物的光降解研究有了大量报道。本文阐述了土壤组成和质地、土壤湿度、土壤pH值和土壤厚度等因素对光解影响的研究现状;介绍了目前研究土壤光降解所采用的研究方法：土壤表层直接光解、土壤悬浮液光解、溶剂萃取与光降解联合处理,及其研究土壤光降解应用的动力模型;对不同农药和其它有机污染物在土壤中的光降解研究进行了综述,并对今后的研究作了展望。     

The combined effect of persistent organic pollutants in the serum POP mixture in Greenlandic Inuit: xenoestrogenic,xenoandrogenic and dioxin-like transactivities

Greenlandic Inuit have high body burden of persistent organic pollutants (POPs). We analyzed the combined effect of the actual lipophilic serum POP mixture on estrogen-, androgen- and aryl hydrocarbon-receptor functions as effect biomarkers, and the associations between the effect biomarkers and serum POPs, and lifestyle characteristics. The serum POPs were extracted from 232 Inuit from Ittoqqortoormiit, Narsaq and Qeqertarsuaq. The POP-related receptor transactivities correlated negatively to the POP levels and were associated to the lifestyle characteristics. The POP-related receptor transactivities can be used as effect biomarkers. The serum POPs have hormone disruptive potentials.     

MB-COMT promoter DNA methylation is associated with working-memory processing in schizophrenia patients and healthy controls

Many genetic studies report mixed results both for the associations between COMT polymorphisms and schizophrenia and for the effects of COMT variants on common intermediate phenotypes of the disorder. Reasons for this may include small genetic effect sizes and the modulation of environmental influences. To improve our understanding of the role of COMT in the disease etiology, we investigated the effect of DNA methylation in the MB-COMT promoter on neural activity in the dorsolateral prefrontal cortex during working memory processing as measured by fMRI - an intermediate phenotype for schizophrenia. Imaging and epigenetic data were measured in 102 healthy controls and 82 schizophrenia patients of the Mind Clinical Imaging Consortium (MCIC) study of schizophrenia. Neural activity during the Sternberg Item Recognition Paradigm was acquired with either a 3T Siemens Trio or 1.5T Siemens Sonata and analyzed using the FMRIB Software Library (FSL). DNA methylation measurements were derived from cryo-conserved blood samples. We found a positive association between MB-COMT promoter methylation and neural activity in the left dorsolateral prefrontal cortex in a model using a region-of-interest approach and could confirm this finding in a whole-brain model. This effect was independent of disease status. Analyzing the effect of MB-COMT promoter DNA methylation on a neuroimaging phenotype can provide further evidence for the importance of COMT and epigenetic risk mechanisms in schizophrenia. The latter may represent trans-regulatory or environmental risk factors that can be measured using brain-based intermediate phenotypes.     

MB-COMT promoter DNA methylation is associated with working-memory processing in schizophrenia patients and healthy controls

Many genetic studies report mixed results both for the associations between COMT polymorphisms and schizophrenia and for the effects of COMT variants on common intermediate phenotypes of the disorder. Reasons for this may include small genetic effect sizes and the modulation of environmental influences. To improve our understanding of the role of COMT in the disease etiology, we investigated the effect of DNA methylation in the MB-COMT promoter on neural activity in the dorsolateral prefrontal cortex during working memory processing as measured by fMRI - an intermediate phenotype for schizophrenia. Imaging and epigenetic data were measured in 102 healthy controls and 82 schizophrenia patients of the Mind Clinical Imaging Consortium (MCIC) study of schizophrenia. Neural activity during the Sternberg Item Recognition Paradigm was acquired with either a 3T Siemens Trio or 1.5T Siemens Sonata and analyzed using the FMRIB Software Library (FSL). DNA methylation measurements were derived from cryo-conserved blood samples. We found a positive association between MB-COMT promoter methylation and neural activity in the left dorsolateral prefrontal cortex in a model using a region-of-interest approach and could confirm this finding in a whole-brain model. This effect was independent of disease status. Analyzing the effect of MB-COMT promoter DNA methylation on a neuroimaging phenotype can provide further evidence for the importance of COMT and epigenetic risk mechanisms in schizophrenia. The latter may represent trans-regulatory or environmental risk factors that can be measured using brain-based intermediate phenotypes.     

宫颈癌患者血浆中E-钙黏着蛋白基因启动子区的甲基化状态

肿瘤细胞可以释放DNA进入患者的血浆/血清中,并可作为无创伤性诊断肿瘤的标记物。采用甲基化特异性聚合酶链式反应(MS-PCR)结合亚硫酸盐测序法对151例宫颈癌患者血浆和对应的30例组织中E-钙黏着蛋白基因启动子区甲基化状态进行检测,并与化学发光法检测患者血清的鳞状上皮癌抗原(SCC)相比较,发现此方法的灵敏度为40.39%,特异性为100%,正确性为49.72%,血浆和组织的符合率为76.67%。宫颈炎、子宫肌瘤和正常人的血浆中均未检测到甲基化状态的存在。随着临床分期和组织学分级的增加,E-钙黏着蛋白基因甲基化的检出率也在逐渐增加,与SCC结果相比,MS-PCR方法在早期和恶性度高的宫颈癌中的诊断效果良好。使用E-钙黏着蛋白基因作为分子标记可以对宫颈癌患者进行无创伤性早期诊断和预后的评估。     

Gene promoter methylation in colorectal cancer and healthy adjacent mucosa specimens

We evaluated the promoter methylation levels of the APC, MGMT, hMLH1, RASSF1A and CDKN2A genes in 107 colorectal cancer (CRC) samples and 80 healthy adjacent tissues. We searched for correlation with both physical and pathological features, polymorphisms of folate metabolism pathway genes (MTHFR, MTRR, MTR, RFC1, TYMS, and DNMT3B), and data on circulating folate, vitamin B12 and homocysteine, which were available in a subgroup of the CRC patients. An increased number of methylated samples were found in CRC respect to adjacent healthy tissues, with the exception of APC, which was also frequently methylated in healthy colonic mucosa. Statistically significant associations were found between RASSF1A promoter methylation and tumor stage, and between hMLH1 promoter methylation and tumor location. Increasing age positively correlated with both hMLH1 and MGMT methylation levels in CRC tissues, and with APC methylation levels in the adjacent healthy mucosa. Concerning gender, females showed higher hMLH1 promoter methylation levels with respect to males. In CRC samples, the MTR 2756AG genotype correlated with higher methylation levels of RASSF1A, and the TYMS 1494 6bp ins/del polymorphism correlated with the methylation levels of both APC and hMLH1. In adjacent healthy tissues, MTR 2756AG and TYMS 1494 6bp del/del genotypes correlated with APC and MGMT promoter methylation, respectively. Low folate levels were associated with hMLH1 hypermethylation. Present results support the hypothesis that DNA methylation in CRC depends from both physiological and environmental factors, with one-carbon metabolism largely involved in this process.     

慢速渗滤土地处理系统中优先有机物的迁移、归宿与生态风险

研究了沈阳西部城市污水慢速渗滤土地处理系统中优先有机污染物的迁移和残留情况,结果表明,土地处理系统和当地传统污灌区耕作层土壤、地下水中的优先有机污染物的总含量分别高于对照区（清水灌区）１倍和４倍以上;系统出水、地下水和传统污灌区地下水中的优先有机污染物的浓度有相似的分布、说明污灌水中的有机污染物对土壤和地下水产生一定程度的影响,但土地处理系统和当地传统污灌区生产的大米中,优先有机污染物含量与对照区相比未见显著差异．     

E-钙粘蛋白基因启动子区域单核苷酸基因多态性(-160A/C)和大肠癌遗传易感性的联系

目的:探讨E-钙粘蛋白基因(CDH1)启动子区域-160A/C单核苷酸基因多态性(single nucleotide polymorphism,SNP)和中国地区散发大肠癌(colorectal cancer,CRC)人群遗传易感性的联系。方法:以中国地区大肠癌病人群为研究基础,同时建立无肿瘤家族史以及其它遗传性疾病史的正常对照组,进行病例对照研究,采用聚合酶链反应-限制性片段长度多态性技术(polymerasechain reaction-restriction fragment length polymorphism,PCR-RFLP)行目的基因的多态性测定,同时行正常结肠组织和大肠癌组织的E-钙粘蛋白的免疫组化测定。结果:正常对照组和大肠癌组的目的基因型分布频率并无统计学差异(x2检验,P=0.602),同时A基因型和C基因型在正常结肠组织和大肠癌组织中E-钙粘蛋白的表达量也并无差异(t检验,P>0.05)。结论:CDH1启动子区域-160A/C单核苷酸基因多态性中并不单独增加大肠癌的发病风险。     

Global DNA methylation in a population with aflatoxin B1 exposure

We previously reported that global DNA hypomethylation, measured as Sat2 methylation in white blood cells (WBC), and aflatoxin B₁ (AFB₁) exposure were associated with increased hepatocellular carcinoma risk. In this study, we assessed the association between AFB₁ exposure and global DNA methylation. We measured LINE-1 and Sat2 methylation in WBC DNA samples from 1140 cancer free participants of the Cancer Screening Program (CSP) cohort. Blood and urine samples were used to determine the level of AFB₁-albumin (AFB₁-Alb) adducts and urinary AFB₁ metabolites. In continuous models, we found reverse associations of urinary AFB₁ with LINE-1 and Sat2 methylation. The odds ratio (OR) per 1 unit decrease were 1.12 (95%CI = 1.03–1.22) for LINE-1 and 1.48 (95%CI = 1.10–2.00) for Sat2 methylation. When compared with subjects in the highest quartile of LINE-1, we found that individuals in the 2nd and 3rd quartiles were less likely to have detectable AFB₁-Alb adducts, with ORs (95%CI) of 0.61 (0.40–0.93), 0.61 (0.40-.94), and 1.09 (0.69–1.72), respectively. The OR for detectable AFB₁-Alb was 1.81 (95%CI = 1.15–2.85) for subjects in the lowest quartile of Sat2 methylation. The OR for detection of urinary AFB₁ for those with LINE-1 methylation in the lowest quartile compared with those in the highest quartile was 1.87 (95%CI = 1.15–3.04). The corresponding OR was 1.75 (95%CI = 1.08–2.82) for subjects in the lowest quartile of Sat2 methylation. The association between AFB₁ exposure and global DNA methylation may have implications for the epigenetic effect of AFB₁ on hepatocellular carcinoma development and also suggests that changes in DNA methylation may represent an epigenetic biomarker of dietary AFB₁ exposure.