Sorption of toxic heavy metals to soil

The surface soil is a major recipient of pollutants, including heavy metals, through atmospheric deposition, agricultural practices, and waste disposal. In the present work the sorption capacity of different types of soils to toxic heavy metals, i.e. chromium, copper, cadmium and lead has been studied. Experimental adsorption data for metals to the soil obtained by the batch method were fitted by linear isotherm. The various soils showed a very different behaviour in sorption of heavy metals. The distribution coefficient Kd, which is an indication of the adsorbing capacity of the substrate, varies within a wide range, from 57 to 53,000 l kg-1. Desorption of metals from the solid phase was found to be small, indicating that the soil matrix is affecting the metal mobility by modifying the bonding of pollutants to the soil system consequently affecting the potential for soil remediation processes.     

An integrated model describing the toxic responses of Daphnia magna to pulsed exposures of three metals

Some toxicology research in which toxicant exposures are continual (pulsed) rather than continuous have been reported. A number of toxicity models have been developed for pulsed and continuous exposures. Most of these models were developed based on one- or two-compartment, first-order toxicokinetics and were calibrated with organic compounds. In the present study, the relationship between mortality (after 21 d) of Daphnia magna in response to pulsed and continuous exposures to Cu, Zn, and Se was used to develop a model that integrated the effects of single and multiple pulsed metal exposures based on first-order uptake and depuration kinetics. Mortality was a function of exposure concentration, duration, and recovery time between exposures. The model was successfully validated using an independent data set. It is applicable to risk assessment and, potentially, may be incorporated with other models (e.g., the biotic ligand model) to predict the toxicity of pulsed metal exposures under a range of environmental conditions.     

甲苯职业接触者血清蛋白质谱差异的研究

目的研究甲苯接触工人与健康人群蛋白质图谱差异。方法收集甲苯接触工人(6例)和健康人群(6例)的血清,采用蛋白质组学非标记Label free质谱分析技术进行蛋白鉴定和定量,对甲苯接触组与健康对照组样本差异表达的蛋白质进行分析,应用生物信息学工具分析筛选到的蛋白质功能及其参与生物过程。结果蛋白质组学结果显示甲苯接触工人组与健康对照组之间差异表达超过2倍以上有39个蛋白,其中24个在甲苯接触工人组血清中表达上调,15个蛋白质在甲苯接触工人组表达下调。筛选到的这些蛋白质主要涉及信号转导、丝氨酸内肽酶活力、炎性反应、蛋白修饰、应激反应、凝血反应等过程。结论差异表达的蛋白质为甲苯接触人群的健康评估和早期疾病诊断提供了潜在蛋白标志物,有助于对甲苯早期中毒的分子机制的理解。     

Characterization of proteomic and metabolomic responses to dietary factors and supplements

Over the past decade there has been a renewed interest in research and development of both dietary and nutritional supplements. Significant advancements have been made in the scientific assessment of the quality, safety, and efficacy of these products because of the strong interest in and financial support of these projects. As research in both fields continues to advance, opportunities to use new and innovative research technologies and methodologies, such as proteomics and metabolomics, are critical for the future progress of the science. The purpose of the symposium was to begin the process of communicating new innovative proteomic and metabolomic methodologies that may be applied by researchers in both the nutrition and the natural product communities. This symposium highlighted 2 proteomic approaches, protein fingerprinting in complex mixtures with peptoid microarrays and top-down mass spectrometry for annotation of gene products. Likewise, an overview of the methodologies used in metabolomic profiling of natural products was presented, and an illustration of an integrated metabolomics approach in nutrition research was highlighted.     

氢醌刺激后人肝细胞蛋白质谱表达的变化

目的研究氧醌(HQ)刺激后L-02型人肝细胞蛋白质谱的表达变化。方法传代培养的L-02型肝细胞分为空白对照组和染毒处理组。处理组经HQ(1×10-4mol／L)染毒培养24 h,对照组不做处理。提取蛋白同时进行双向凝胶电泳,图谱经PDQuest软件分析寻找差异点。实验独立进行3次,每次处理组和对照组各设3块胶作为组内重复,切取重复性较好的差异点做MALDI-TOF质谱鉴定,得到PMF通过Mascot在美国国家生物信息检索中心(NCBI)人类蛋白质数据库搜索。结果每块胶检测到约1 000个蛋白点,对照组和处理组凝胶匹配率组内达90％以上,组间80％以上,3次实验各发现17、18、24个蛋白点表达改变,变化倍数≥2。重复性较好的4个蛋白点经MALDI-TOF质谱鉴定为Rho GDP解离抑制蛋白、6-磷酸葡萄糖内酯酶、erbB3结合蛋白EBP1和核纤层蛋白,其功能与信号转导、细胞骨架及能量代谢有关。结论1×10-4mol／L的HQ处理24 h可引起L-02型人肝细胞蛋白质谱表达改变。     

利用蛋白质组学技术研究氢醌刺激后人胚肺成纤维细胞蛋白质表达改变

目的　研究氢醌 (HQ)对人胚肺成纤维细胞 (HLF)蛋白质表达的影响 ,以阐明氢醌引起细胞应答反应的分子机制。方法　细胞受HQ刺激后 ,加入裂解液 ,取上清丙酮沉淀 ,蛋白定量。双向凝胶电泳分离蛋白质组成分 ,胶体考马斯亮兰显色 ,Imagemaster2 0进行图像分析后选取差异点 ,胶内酶解后MALDI TOF进行肽指纹图谱鉴定。结果　图像分析结果显示 ,对照组HLF细胞检测到 4 90± 2 8个蛋白点 ,HQ染毒组为 4 38±2 3个。氢醌刺激后 15个蛋白斑点发生变化 ,初步鉴定了其中 8个蛋白斑点 ,包括一些氧化应激和细胞骨架相关蛋白。结论　氢醌可引起HLF细胞蛋白表达改变。     

Biokinetics and tolerance development of toxic metals in Daphnia magna

Daphnia magna is widespread in many freshwater systems of temperate regions and frequently is used to test metal toxicity. Recently, studies have been performed to determine metal biokinetics and development of tolerance in this important zooplankton species. In the present paper, we review the recent progress in these areas and suggest possible directions for future studies. Substantial differences exist in aqueous uptake, dietary assimilation, and elimination of several metals (Cd, Se, Zn, Ag, Hg, and MeHg) by D. magna. The routes of uptake are metal-specific, with Se and MeHg being accumulated predominantly through diet. All metals except Ag can be biomagnified from algae to D. magna, providing that metal concentrations in algae and algal food density are relatively low. Methylmercury is biomagnified in all situations. As a route for metal elimination in D. magna, maternal transfer is especially important for Se, Zn, and MeHg. On the other hand, the effect of single-generation exposure to metals on D. magna is very different from multigeneration exposure, which often results in a significantly higher metal tolerance. Moreover, D. magna easily loses metal tolerance developed through long-term exposure. Recovery from metal stress can temporarily increase the sensitivity of D. magna to metal toxicity. Finally, metallothionein-like protein is responsible for minimizing metal toxicity in D. magna. The results inferred from these studies can be extrapolated to other aquatic invertebrates as well as to other pollutants in the aquatic environment.     

Approaches to modeling toxic responses of aquatic organisms to aromatic hydrocarbons

Acute toxic effects on Salmo gairdneri, Poecilia reticulata, Daphnia magna, and the growth inhibition of Selenastrum capricornutum were measured for eight aromatic hydrocarbons. Toxicity measurements were carried out following the OECD standard guidelines modified as appropriate in order to prevent hydrocarbon loss by volatilization; the concentrations of the substrates in the test solutions were periodically measured by HPLC. The toxic responses were analyzed in terms of the n-octanol/water partition coefficients, by means of linear regression analysis, and in terms of five molecular properties simultaneously, by means of the partial least squares analysis in latent variables (PLS). The univariate and multivariate quantitative structure-activity relationship models obtained by the two approaches are compared and discussed.     

Exposure of children to heavy metals from smelters: Epidemiology and toxic consequences

To evaluate the epidemiologic and toxicologic consequences of environmental exposure to heavy metals, we examined populations of children living near 21 primary, nonferrous metal smelters in the United States. At lead smelters in El Paso, Texas, and in Kellogg, Idaho, 59 and 99%, respectively, of 1- through 9-year-old children living within 1.6 km of the smelting plants had blood lead levels ?40 μ/dl, indicating greater than normal lead absorption. Children living within 3.2 km of 10 of 11 copper smelters had increased urine arsenic levels, indicating increased systemic absorption of arsenic. Elevated blood cadmium levels were found for children in Bartlesville, Oklahoma, who lived within 3.2 km of a zinc smelter. Biological levels of heavy metals in these populations were related inversely to distance of residence from the smelting plants and were in direct proportion to levels of environmental contamination. Inhalation and ingestion of heavy metal particulates emitted by the smelters into air, soil, and dust were the principal causes of increased absorption. Elevated levels of erythrocyte protoporphyrin, as well as anemia and slowed motor nerve conduction velocity were the dose-related toxic consequences of lead absorption observed in the children studied. These data illustrate the importance of smelters as point sources of heavy metal contamination and as models for epidemiologic study.     

Evaluation of occupational exposure to toxic metals released in the process of aluminum welding

The objective of this study was to evaluate occupational exposure to welding fumes and its elements on aluminum welders in Polish industry. The study included 52 MIG/Al fume samples and 18 TIG/Al samples in 3 plants. Air samples were collected in the breathing zone of welders (total and respirable dust). Dust concentration was determined gravimetrically, and the elements in the collected dust were determined by AAS. Mean time-weighted average (TWA) concentrations of the welding dusts/fumes and their components in the breathing zone obtained for different welding processes were, in mg/m3: MIG/Al fumes mean 6.0 (0.8-17.8), Al 2.1 (0.1-7.7), Mg 0.2 (< 0.1-0.9), Mn 0.014 (0.002-0.049), Cu 0.011 (0.002-0.092), Zn 0.016 (0.002-0.14), Pb 0.009 (0.005-0.025), Cr 0.003 (0.002-0.007), and TIG/Al fumes 0.7 (0.3-1.4), Al 0.17 (0.07-0.50). A correlation has been found between the concentration of the main components and the fume/dust concentrations in MIG/Al and TIG/Al fumes. Mean percentages of the individual components in MIG/Al fumes/dusts were Al: 30 (9-56) percent; Mg: 3 (1-5.6) percent; Mn: 0.2 (0.1-0.3) percent; Cu: 0.2 (< 0.1-1.8) percent; Zn: 0.2 (< 0.1-0.8) percent; Pb: 0.2 (< 0.1-1) percent; Cr: < 0.1 percent. The proportion of the respirable fraction in the fumes and their constituents varied between 10 percent and 100 percent. The results showed that MIG/Al fumes concentration was 1.2 times higher than the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV), and the index of the combined exposure to the determined agents was 2.3 (0.4-8.0), mostly because of high Al2O3 contribution. The background concentrations of the components (ca. 5-10 times lower than those in the breathing zone of the welders) did not exceed the Polish MAC value. The elemental composition of total and respirable fume/dust may differ considerably depending on welding methods, the nature of welding-related operations, and work environment conditions.     

Genomic and proteomic portrait of a novel mycobacteriophage SWU2 isolated from China

Phage therapy, especially combination with antibiotics, was revitalized to control the antibiotics resistance. Mycobacteriophage, the phage of mycobacterium with the most notorious Mycobacterium tuberculosis (M. tuberculosis), was intensively explored. A novel mycobacteriophage SWU2 was isolated from a soil sample collected at Nanchang city, Jiangxi province, China, by using Mycolicibacterium smegmatis (M. smegmatis) mc² 155 as the host. Phage morphology and biology were characterized. Phage structure proteins were analyzed by LC-MS/MS. The putative functions of phage proteins and multi-genome comparison were performed with bioinformatics. The transmission electron microscopy result indicated that this phage belongs to Siphoviridae of Caudovirales. Plaques of SWU2 appeared clear but small. In a one-step growth test, we demonstrated that SWU2 had a latent period of 30 min and a logarithmic phase of 120 min. Among the 76 predicted Open Reading Frames (ORFs), 9 ORFs were identified as phage structure proteins of SWU2. The assembled phage genome size is 50,013 bp, with 62.7% of G + C content. SWU2 genome sequence shares 88% identity with Mycobacterium phages HINdeR and Timshel, differing in substitutions, insertions and deletions in SWU2. Phylogenetic tree revealed that SWU2 is grouped into A7 sub-cluster. There are several substitutions, insertions and deletions in SWU2 genome in comparison with close cousin phages HINdeR and Timshel. The new phage adds another dimension of abundance to the mycobacteriophages.     

FS在人肺腺癌细胞中表达及其生物学作用

目的 探讨卵泡抑素(FS)在人肺腺癌细胞中的表达及其作用。方法 免疫细胞化学染色检测肺腺癌细胞FS表达情况,细胞计数试剂盒测定细胞增殖,流式细胞术检测细胞凋亡。结果 免疫细胞化学染色显示人肺腺癌细胞表达FS;40、50 ng/mL激活素A组肺腺癌细胞增殖((吸光度值A分别为(0.49±0.07)及(0.42±0.08))明显低于对照组(0.62±0.09);如果预先用抗FS单克隆抗体中和内源FS后,10 ng/mL激活素A也能抑制肺腺癌细胞增殖(0.48±0.06),由其诱导的肺腺癌细胞凋亡率(24.8±6.7)%明显高于单独激活素A组细胞凋亡率(7.3±2.4)%。结论 肺腺癌细胞表达的FS有利于肺腺癌细胞生存,阻断FS分泌或其生物学作用对治疗肺腺癌可能具有重要意义。     

利用蛋白质组学技术研究三氯乙烯刺激肝细胞后蛋白质差异表达

目的应用双向电泳及串联质谱技术，研究不同剂量三氯乙烯（TCE）诱导L-02肝细胞蛋白质表达谱的差异。方法L-02肝细胞分别用不同剂量TCE和溶剂对照（二甲亚砜）处理后，提取细胞总蛋白，双向凝胶电泳分离蛋白质组成分，银染显色，经ImageMaster 2D Platinum 5．0软件分组分析比较四组图谱，并对差异蛋白斑点进行基质辅助激光解吸／电离飞行时间串联质谱（MALDI-TOF-TOF-MS）分析鉴定。结果得出差异较明显的蛋白质斑点15个，不同剂量TCE刺激后表达分别上调、下调或消失，提示TCE可引起肝细胞蛋白表达发生改变。通过质谱鉴定和IPI human数据库检索，鉴定了其中9个TCE诱导L02肝细胞相关的蛋白质。结论这些结果为深入研究TCE毒作用相关的蛋白质及TCE毒作用的分子标志物提供依据，并为阐明TCE毒作用的分子机制提供线索。     

Oxidative damage in human epithelial alveolar cells exposed in vitro to oil fly ash transition metals

Among particulate matter emissions from combustion processes, oil fly ash (OFA) displays a marked oxidative and inflammogenic reactivity, due to the high content of bioavailable transition metals. In the present study, we evaluated the biological effects of an OFA water solution, composed of the transition metals Fe (57.5%), V (32.4%), and Ni (10.1%), in human epithelial alveolar cells (A549 line). The fluorimetric analysis by 2',7'-dichlorofluorescein showed a significant, dose- and time-dependent induction of intracellular reactive oxygen species (ROS) triggered by OFA metal components at subtoxic doses. The metal chelator deferoxamine and the radical scavenger dimethylsulfoxide attenuated the metal-induced generation of ROS. Confocal microscopy observations strengthened these findings and showed an intense cytoplasmic fluorescence with perinuclear thickenings in A549 cells, in the absence of morphological damage. Metal-induced generation of ROS was significantly correlated with a dose- and time-dependent DNA damage, as assessed by single cell gel electrophoresis (comet assay). Catalase was able to decrease dramatically DNA damage. Fluorimetric analyses by diphenyl-1-pyrenylphosphine showed a parallelism between generation of ROS and formation of lipid peroxides. The results obtained in the experiments evaluating the effects of individual metal solutions did not show any significant difference in DNA damage between Fe(III) and V(IV), but highlighted the higher capability of V(IV) to increase ROS in the cytoplasmic compartment. The different behavior of these two elements, confirmed by the weak Fe-induced lipid peroxidation, may be ascribed to the presence of Fe-binding proteins, such as ferritin, in the cytoplasm. Finally, Ni(II) had negligible effects on ROS production. On the whole, the results obtained in this study show the strong capability of transition metals adsorbed to OFA to cause widespread damage to biological macromolecules, and suggest potential health effects resulting from exposure to power plant emissions in industrialized sites.