Evaluation of estrogenic activities and mechanism of action of perfluorinated chemicals determined by vitellogenin induction in primary cultured tilapia hepatocytes

Perfluorochemicals (PFCs) are emerging persistent organic pollutants (POPs) and are widely present in the environment, wildlife and humans. Recently, reports have suggested that PFCs may have endocrine-disrupting activities. In the present study, we have developed a non-competitive enzyme-linked immunosorbent assay (ELISA) method to investigate estrogenic activities of selected PFCs using vitellogenin (VTG) induction in primary cultured hepatocytes of freshwater male tilapia (Oreochromis niloticus). Cultured hepatocytes were exposed to various concentrations of perfluorooctanyl sulfonate (PFOS), pentadecafluorooctanoic acid (PFOA), 1H, 1H, 2H, 2H-nonafluoro-1-hexanol (4:2 FTOH), 1H, 1H, 2H, 2H-perfluorooctanol (6:2 FTOH) and 1H, 1H, 2H, 2H-perfluoro-1-decanol (8:2 FTOH) for 48h, while 17 beta-estradiol (E2) and 4-nonylphenol (4-NP) were used as positive controls. A dose-dependent induction of VTG was observed in E2-, 4-NP-, PFOS-, PFOA- and 6:2 FrOH-treated cells, whereas VTG levels remained unchanged in the 4:2 FTOH and 8:2 FTOH exposure groups at the concentrations tested. The estimated 48-h EC50 values for E2,4-NP, PFOS, PFOA and 6:2 FTOH were 4.7 x 10(-7), 7.1 x 10(-6), 1.5 x 10(-5), 2.9 x 10(-5) and 2.8 x 10(-5) M, respectively. In the time-course study, significant VTG induction took place at 24 h (E2), 6 It (4-NP), 48 It (PFOS), 48 It (PFOA), 72 It (4:2 FTOH), 12 h (6:2 FTOH), 72 h (8:2 FTOH), and increased further after 96 It of exposure. Co-exposure to binary mixtures of individual PFCs and E2 for 48 It significantly inhibited E2-induced hepatocellular VTG production in a dose-dependent manner except for 4:2 FTOH. The estimated 48-h IC50 (concentration of a compound that elicits 50% inhibition of maximally E2-induced VTG) values for PFOS, PFOA, 6:2 FTOH and 8:2 FTOH were 3.1 x 10(-7), 5.1 X 10(-7), 1.1 X 10(-6) and 7.5 x 10(-7) M, respectively. In order to further investigate the estrogenic mechanism of PFCs, the hepatocytes were co-exposed to binary mixtures of individual chemicals (E2,4-NP, PFOS, PFOA and 6:2 FTOH) and the known estrogen receptor inhibitor tamoxifen for 48 h; tamoxifen significantly inhibited the ability of these chemicals to stimulate vitellogenesis. The overall results demonstrated that PFOS, PFOA and FTOHs have estrogenic activities and that exposure to a combination of E2 and PFCs produced anti-estrogenic effects. The results of the estrogen receptor inhibition assay further suggested that the estrogenic effect of PFCs may be mediated by the estrogen receptor pathway in primary cultured tilapia hepatocytes. (c) 2007 Elsevier B.V. All rights reserved.

Direct toxicity assessment of toxic chemicals with electrochemical method

Electrochemical measurement of respiratory chain activity is a rapid and reliable screening for the toxicity on microorganisms. Here, we investigated in-vitro effects of toxin on Escherichia coli (E. coli) that was taken as a model microorganism incubated with ferricyanide. The current signal of ferrocyanide effectively amplified by ultramicroelectrode array (UMEA), which was proven to be directly related to the toxicity. Accordingly, a direct toxicity assessment (DTA) based on chronoamperometry was proposed to detect the effect of toxic chemicals on microorganisms. The electrochemical responses to 3,5-dichlorophenol (DCP) under the incubation times revealed that the toxicity reached a stable level at 60 min, and its 50% inhibiting concentration (IC50) was estimated to be 8.0 mg L-1. At 60 min incubation, the IC50 values for KCN and As2O3 in water samples were 4.9 mg L-1 and 18.3 mg L-1, respectively. But the heavy metal ions, such as Cu2+ Pb2+ and Ni2+, showed no obvious toxicity on E. coli.

Influence of methanol on retention of hydrophobic organic chemicals in soil leaching column chromatography

The influence of methanol in methanol-water mixed eluents on the capacity factor (P), an important parameter which could depict leaching potential of hydrophobic organic chemicals (HOCs) in soil leaching column chromatography (SLCC), was investigated. Two reference soils, GSE 17201 obtained from Bayer Landwirtschaftszentrum, Monheim, Germany and SP 14696 from LUFA, Spencer, Germany, were used as packing materials in soil columns, and isocratic elution with methanol-water mixtures at different volume fractions of methanol (phi) were tested. Shortterm exposure of the column (packed with the GSE 17201 soil) to the eluents increased solute retention by a certain (23% log-unit) degree evaluated through a correlation with the retention on the same soil column but unpreconditioned by methanol-containing eluents. Long-term exposure of soil columns to the eluents did not influence the solute retention. A log-linear equation, log k' = log k'(w) - Sphi, could well and generally describe the retention of HOCs in SLCC. For the compounds of homologous series, logk'(w), had good linear relationship with S, indicating the hydrophobic partition mechanism existing in the retention process. (C) 2002 Elsevier Science Ltd. All rights reserved.

Retention behavior of hydrophobic organic chemicals as a function of temperature in soil leaching column chromatography

To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in soil/solvent system, a soil leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20-40 degreesC was carried out, which utilized a reference soil (SP 14696) packed column and a methanol-water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 degreesC (k'(30)/k'(40)) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C-18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability-dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former. (C) 2002 Elsevier Science Ltd. All rights reserved.

Distribution patterns of PCDD/Fs in chlorinated chemicals

The purpose of this research was to determine polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in five chlorinated chemicals (phthalocyanine copper, phthalocyanine green, chloranil-1 and 2, and triclosan), and to compare their 2,3,7,8-tetrachlordibenzo-IpI-dioxin equivalents (TEQ). The distribution patterns of total PCDD/Fs and 2,3,7,8-substituted PCDD/Fs were elucidated in detail. The TEQ values of toxic PCDD/Fs in all chemicals were in the range of 5.03-1379.55 ng I-TEQ/kg. The contribution of OCDD and OCDF in phthalocyanine green was 75% of the total TEQ. For chloranils, the maximum contribution of toxic PCDD/Fs was from 2,3,7,8-substituted HxCDF and 2,3,7,8-substituted HpCDF. The TEQ of HxCDF and HpCDF in chloranil-1 was 90% and in chloranil-2 was 71%. And the toxic contribution increased with the degree of chlorination for PCDFs. (C) 2005 Elsevier Ltd. All rights reserved.

Destruction of Chemical Agents in a Plasma Reactor with Working Gas of Hydrogen

Microfluidic effects of transporting signaling components in cell coculture chips

A theoretical model has been developed to investigate the microfluidic transport of the signaling chemicals in the cell coculture chips. Using an epidermal growth factor (EGF)-like growth factor as the sample chemical, the effects of velocities and channel geometry were studied for the continuous-flow microchannel bioreactors. It is found that different perfusion velocities must be applied in the parallel channels to facilitate the communication, i.e., transport of the signaling component, between the coculture channels. Such communication occurs in a unidirectional way because the signaling chemicals can only flow from the high velocity area to the low velocity area. Moreover, the effect of the transport of the signaling component between the coculture channels on the growth of the monolayer cells and the multicellular tumor spheroid (MTS) in the continuous-flow coculture environment were simulated using 3D models. The numerical results demonstrated that the concentration gradients will induce the heterogeneous growth of the cells and the MTSs, which should be taken into account in designing the continuous-flow perfusion bioreactor for the cell coculture research.

外源物质对酵母拮抗菌生活力的影响

　　近年来，酵母拮抗菌在水果采后病害防治中展示了良好的应用前景。然而，在实际应用中,酵母拮抗菌在逆境条件下会因为发生凋亡或细胞损伤而引起生活力的下降，最终导致拮抗菌抑病能力降低。研究酵母拮抗菌生活力下降的规律，提高酵母拮抗菌的生产效率，减少剂型加工过程中的细胞损伤，增强其对逆境条件的耐受力是增加或稳定生防制剂防治效果的有效途径。本文主要研究酵母拮抗菌正常培养过程中生活力下降的规律，筛选剂型加工过程中对酵母拮抗菌具有保护作用的化学物质，并对酵母拮抗菌的培养条件进行了优化。主要研究结果如下： 　　1. 在正常培养过程中，酵母拮抗菌Rhodotorula glutinis和Cryptococcus laurentii中细胞染色质凝集或细胞膜破损的发生一般在6天以后。外源加入的N-乙酰半胱氨酸及硅酸钠等物质在超过一定浓度时会加速酵母菌的死亡。 　　2. 在不同的液体悬浮制剂中，对R. glutinis而言，使用磷酸缓冲液（PBS）悬浮时保护效果最好；而C. laurentii悬浮在NYDB培养基中或海藻糖、乳糖溶液中时的生活力最高。 　　3. 以10 %葡萄糖 + 5 %脱脂牛奶作保护剂，可以有效地保持酵母拮抗菌C. laurentii冻干制剂的生活力，配合使用的保护效果高于它们单独使用时的保护效果。添加1 mM N-乙酰半胱氨酸能更好地保持拮抗菌制剂在常温保存过程中的生活力，这可能与这种还原性物质缓解了细胞内活性氧的积累有关。 　　4. 不同酵母拮抗菌对不同碳、氮源的利用能力有明显差异。在9种不同的碳源和10种不同的氮源中，Pichia membranefaciens能够最有效利用的碳、氮源是葡萄糖、果糖和多价胨，而Candida guilliermondii的最佳碳源和氮源分别是果糖和肉蛋白胨。

抚仙湖无机污染物化学背景值及动物体内致突变性评定

为了比较抚仙湖不同区域的水质及其致突变性, 从抚仙湖周围水域采取7 个样点的水样。用电感 耦合氩等离子发射光谱法对水样中的无机污染物作定性和定量分析。另外使用蝌蚪( B uf o buf o andrewsi) 红细 胞微核试验检测抚仙湖水样的致突变性。结果显示: 禄冲采样点水样带有微核的红细胞率增高, 表明这个点水 样有致突变活性物质。

Composition and evolution of the V2r vorneronasal receptor gene repertoire in mice and rats

Pheromones are chemicals produced and detected by conspecifics to elicit social/sexual physiological and behavioral responses, and they are perceived primarily by the vomeronasal organ (VNO) in terrestrial vertebrates. Two large superfamilies of G protein-coupled receptors, V1rs and V2rs, have been identified as pheromone receptors in vomeronasal sensory neurons. Based on a computational analysis of the mouse and rat genome sequences, we report the first global draft of the V2r gene repertoire, composed of similar to 200 genes and pseudogenes. Rodent V2rs are subject to rapid gene births/deaths and accelerated amino acid substitutions, likely reflecting the species-specific nature of pheromones. Vertebrate V2rs appear to have originated twice prior to the emergence of the VNO in ancestral tetrapods, explaining seemingly inconsistent observations among different V2rs. The identification of the entire V2r repertoire opens the door to genomic-level studies of the structure, function, and evolution of this diverse group of sensory receptors. (c) 2005 Elsevier Inc. All rights reserved.

ANTHROPOGENIC ORGANIC CONTAMINANTS IN WATER AND SURFACE SEDIMENTS OF LARGE SHALLOW EUTROPHIC CHAOHU LAKE, CHINA

To characterize the contamination of anthropogenic organic contaminants in the aquatic environment of Chaohu Lake, China, 7 samples for both water and surface sediment were collected in the lake. Organic contaminants were extracted by solid phase extraction (SPE) and Soxhlet extraction from the water and surface sediment samples, respectively, and then analyzed by GC-MS. One hundred and twenty kinds of organic chemicals were detected in these samples including phenol, benzene series, benzaldehydes, ethanol, polycyclic aromatic hydrocarbons (PAHs), sulfur compounds, alcoholic halides, amines, ketones, esters, alkenes and alkanes. Among them, 13 kinds of chemicals were identified as priority pollutants listed by the U.S. Environmental Protection Agency (EPA), such as phthalate esters (PAEs) and PAHs. Besides, the concentrations of 19 of PAEs and PAHs including, priority pollutants identified were also determined. Bis(2-ethylhexyl)phthalate, the predominant component of the analyzed pollutants, was in the range from 72.34 ng g(-1) DW to 613.71 ng g(-1) DW, 14.80 ng L-1 to 47.05 ng L-1 in sediment and water, respectively. The results indicated that the northwest part of the lake was heavily polluted by domestic and industrial wastewater.