The Cytotoxicity of Some Organic Solvents on Isolated Hepatocytes in Monolayer Culture

The cytotoxic effects of volatile and water-insoluble organic solvents (ethylbenzene, tetrachloroethylene, n-hexane) were tested on isolated hepatocytes in monolayer culture by using the 3-(4,5 dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) reduction assay. All of the tested compounds inhibited metabolic activity of hepatocytes and this effect depended on the concentration of solvents in the incubatory medium. The presence of fetal calf serum in the medium did not change the cytotoxicity of xenobiotics. IC₅₀ values calculated on the basis of the MTT assay indicated that ethylbenzene was more cytotoxic than tetrachloroethylene and n-hexane. Using hepatocyte monolayer culture and the MTT assay to assess cytotoxicity of organic solvents causes many technical problems. It seems that it cannot be used as a rapid, cheap, and credible method.     

水环境中雌激素的酶联免疫快速生物筛选技术研究

采用酶联免疫(ELISA)检测技术,对来自长江口及污水处理厂的水样分析典型雌激素雌二醇(E2)的浓度,将检测结果与化学方法检测数据进行比较验证,以阐明ELISA应用于水环境雌激素快速筛选的可行性。结果表明:ELISA的检测限可低至0.5 ng/L,试验的变异系数<30%,具有较高的灵敏性和良好的重复性;ELISA检测长江口水样中E2浓度范围≤0.7 ng/L,污水处理厂水样为2.5～11.5 ng/L,与液相色谱串联质谱(LC-MS/MS)的检测数据进行比较分析,其相关系数R~2为0.9147,表明2种方法具有良好的相关性;ELISA检测所需的水样量比LC-MS/MS更少,使用96微孔板可同时对43个样品进行检测,缩短了多个样品的分析时间,具有快速简便、经济适用的特点。因此,ELISA作为1种快速、简便、灵敏的雌激素高通量筛选技术,可为环境保护部门开展水环境雌激素物质调查和水体雌激素快速诊断等工作提供技术支持。     

Droplet size spectra and deposits of two aerially sprayed Bacillus thuringiensis formulations on artificial samplers and live foliage

Abstract

Two commercial formulations of Bacillus thuringiensis var. kurstaki (BTK), Foray^® 48B and Thuricide^® 48LV, were applied aerially over nine spray blocks in a hardwood forest in West Virginia in 1991. Droplet spectra and spray mass deposits were determined using water‐sensitive paper strips (WSPS), glass micro‐fiber filters (GMFFs), glass plates and castor oil. Mass deposits of BTK were also assessed on natural foliage by two bioassay methods, i.e., feeding of homogenized foliage containing a starch‐sucrose solution and force‐feeding bioassay of foliar extracts containing re‐dissolved protein precipitate. Deposits on canopy foliage and ground samplers were also assessed by total protein assay and enzyme‐linked immunosorbent assay (ELISA). Droplet spectra on the WSPS were different from those on castor oil. Droplets on horizontal ground WSPS were larger than those on vertical ground WSPS. WSPS placed at canopy level collected more droplets than those at ground level. The total protein deposits (ng/cm²) were consistently higher on all blocks than the delta‐endotoxin protein deposits. Spray mass recovery on the ground samplers were low, and ranged from 2.9 to 8.0% of the applied rates.     

应用电致化学发光分子探针技术对微小原甲藻的检测

以双特异分子探针技术(NPA-SH)为基础,运用电致化学发光技术(ECL)和磁性微球分选技术对其进行改进,成功建立了用于赤潮藻类定性定量分析的电致化学发光分子探针(ECL-MP)检测新技术.设计微小原甲藻特异性NPA探针并对其进行联吡啶钌和生物素标记,优化磁性微球使用量,在ECL检测装置中启动电化学反应,建立光信号与微小原甲藻细胞数目间的ECL-MP分析曲线并对其进行验证.结果表明,标记后的NPA探针具有一定的特异性和实用性;4μg是检测20μL目标藻杂交混合液的最适磁性微球使用量;在最适条件下,微小原甲藻细胞数的线性分析范围6.25×102～4×104个;比较ECL-MP和显微计数方法的样品检测结果,在95%置信区间内二者无显著差异(t-检验).ECL-MP方法为实现微小原甲藻现场样品的快速准确检测提供了一种新方法.     

Ecotoxicological Assessment of Sediment, Suspended Matter and Water Samples in the Upper Danube River. A pilot study in search for the causes for the decline of fish catches (12 pp)

Goals, Scope and Background Fish populations, especially those of the grayling (Thymallus thymallus), have declined over the last two decades in the upper Danube River between Sigmaringen and Ulm, despite intensive and continuous stocking and improvement of water quality since the 1970s. Similar problems have been reported for other rivers, e.g. in Switzerland, Great Britain, the United States and Canada. In order to assess if ecotoxicological effects might be related to the decline in fish catch at the upper Danube River, sediment, suspended matter and waste water samples from sewage treatment plants were collected at selected locations and analyzed in a bioanalytical approach using a battery of bioassays. The results of this pilot study will be used to decide if a comprehensive weight-of-evidence study is needed. Methods Freeze-dried sediments and suspended particulate matters were extracted with acetone in a Soxhlet apparatus. Organic pollutants from sewage water were concentrated using XAD-resins. In order to investigate the ecotoxicological burden, the following bioassays were used: (1) neutral red assay with RTL-W1 cells (cytotoxicity), (2) comet assay with RTLW1 cells (genotoxicity), (3) Arthrobacter globiformis dehydrogenase assay (toxicity to bacteria), (4) yeast estrogen screen assay (endocrine disruption), (5) fish egg assay with the zebrafish (Danio rerio; embryo toxicity) and (6) Ames test with TA98 (mutagenicity). Results and Discussion The results of the in vitro tests elucidated a considerable genotoxic, cytotoxic, mutagenic, bacteriotoxic, embryotoxic and estrogenic burden in the upper Danube River, although with a very inhomogeneous distribution of effects. The samples taken from Riedlingen, for example, induced low embryo toxicity, but the second highest 17β-estradiol equivalent concentration (1.8 ng/L). Using the fish egg assay with native sediments, a broad range of embryotoxic effects could be elucidated, with clear-cut dose-response relationships for the embryotoxic effects of contaminated sediments. With native sediments, embryotoxicity was clearly higher than with corresponding pore waters, thus corroborating the view that – at least for fish eggs – the bioavailability of particle-bound lipophilic substances in native sediments is higher than generally assumed. The effect observed most frequently in the fish egg assay was a developmental delay. A comparison of our own results with locations along the rivers Rhine and Neckar demonstrated similar or even higher ranges of ecotoxicological burdens in the Danube River. Conclusions The complex pattern of ecotoxicological effects caused by environmental samples from the Danube River, when assessed in an in vitro biotest battery using both acute and more specific endpoints, showed that integration of different endpoints is essential for appropriate hazard assessment. Overall, the ecotoxicological hazard potential shown has indeed to be considered as one potential reason for the decline in fish catches at the upper Danube River. However, based on the results of this pilot study, it is not possible to elucidate that chemically induced alterations are responsible for the fish decline. Recommendations and Perspective . In order to confirm the ecological relevance of the in vitro results for the situation in the field and especially for the decline of the grayling and other fishes, further integrated investigations are required. For linking the weight of evidence obtained by in vitro assays and fish population investigations, the application of additional, more specific biomarkers (e.g. vitellogenin induction, EROD and micronucleus assay) has been initiated in fish taken from the field as well as in situ investigations.     

Heavy Metal Tolerance in Chromogenic and Non-Chromogenic Marine Bacteria from Arabian Gulf

A simple method – direct agar diffusion assay – was optimised for rapid assessment of heavy metal toxicity to marine chromogenic and non-chromogenic bacteria. The procedure involved spotting of a 10 microliter test solution on the seeded agar plate and incubation of the plates at 30°C to accelerate bacterial growth. Under optimum conditions, test results were obtainable within 12–18 hr instead of 96 hr incubation time generally required for a marine bacterial assay by conventional agar plate methods. A range of sixteen heavy metals, each at 5 different concentrations was tested. Toxicity was demonstrated by the formation of a clear zone of growth inhibition around the point of application. Toxicity of tested chemicals could be easily demonstrated at concentrations as low as 0.1 g per spot on the agar plate. A dose dependent relation between metal concentration (g/spot) and the diameter of the clear zone on agar plate was observed, suggesting potential of this method as an easy and economical tool in quantitative toxicology studies.     

用蛋白磷酸酶抑制法测定水体中的微囊藻毒素类物质

建立了一种灵敏的测定水体中微囊藻毒素类物质的方法。从鱼肝脏中分离的蛋白磷酸酶２Ａ被微囊藻毒素抑制，并且抑制与毒素剂量相关，抑制模式表现为典型的Ｓ型曲线。根据末知样品存在时蛋白磷酸酶的相对活力，可由本研究得出的标准曲线及公式，计算样品中可能存在的微囊藻毒素类物质。研究表明，在一年的观测周期内，即使没有可见的水华发生，东湖及鱼池中仍有可检测出微囊藻毒素类物质。     

Cystic fibrosis prenatal diagnosis: Confirmation of an equivocal microvillar enzyme result by direct analysis of the common gene mutation

A child was tentatively diagnosed as having cystic fibrosis, based on neonatal presentation with severe gastrointestinal complications; the diagnosis was not confirmed biochemically and no tissues were available for DNA analysis. The mother presented in her subsequent pregnancy, and microvillar enzyme analysis of cell-free amniotic fluid at both 18 and 20 weeks gestation gave equivocal results. The pregnancy was terminated voluntarily because of a trend towards abnormal enzyme assay results on the second amniocentesis. Retrospectively, fetal tissues were found to be homozygous for the most common mutation of the cystic fibrosis gene (AF₅₀₈), which confirmed the prenatal assessment and suggested that the first infant of the couple was probably also affected by the disease.     

二氧化硫亚慢性染毒对大鼠肺细胞DNA的损伤

为了探讨低浓度SO2长期暴露对哺乳动物肺细胞DNA的影响,采用动式吸入法(SO2浓度为28mg/m3)对Wistar大鼠染毒30d,运用单细胞凝胶电泳技术(彗星试验)研究了SO2亚慢性染毒对大鼠肺细胞DNA的损伤作用.结果表明,SO2可引起雌、雄性大鼠肺细胞核DNA迁移长度显著增加(P<0.01),且SO2对雄性小鼠肺细胞DNA损伤比雌性小鼠严重;经染毒后,与对照组相比,大鼠的体重减轻,肺体比增加.这些结果表明,较低浓度的SO2也具有引起哺乳动物肺细胞DNA突变的潜在危险.表3参15     

三类氧化硅的形态分布及其转化特性

本文对以硅酸钠与工业水玻璃为原料酸化制备三类氧化硅(Silica A,B,C)作了较为详细的探讨。应用逐时络合比色与光子相关光谱(PCS)等形态表征方法,对制备过程中的诸多影响因素进行了研究。结果表明,在0.02—0.4mol·1~(-1)范围内浓度对形态分布无甚影响,而滴定速率与熟化时间对形态分布有较大影响。所得Silica A,B,C样品中其主要形态所对应的分别是Si_a,Si_b,与小颗粒态Si_c,大颗粒态Si_c。