乙烯菌核利在水溶液中的光解动力学

以高压汞灯和太阳光为光源,研究乙烯菌核利在重蒸水、自来水、湖水及pH缓冲液中的光解动力学。高压汞灯下,乙烯菌核利在重蒸水中的光解半衰期约为28 m in,而在太阳光下为3.86 h。自来水和湖水中溶解性物质对乙烯菌核利在高压汞灯下的光解动力学仅有微弱的淬灭效应,但在太阳光下表现出显著的敏化效应,照光3 h的敏化效率分别为138%和126%。2种光源下,pH 5.0和pH 7.0缓冲液对乙烯菌核利的光解均表现为光淬灭效应,高压汞灯照光60 m in的淬灭效率分别为69%和57%,太阳光照光7 h的淬灭效率分别为77%和33%;pH 9.0缓冲液则表现出显著的敏化效应,高压汞灯照光20 m in的敏化效率为58%,而太阳光照光1 h的敏化效率则达到了415%。     

Screening differentially expressed genes in an amphipod (Hyalella azteca) exposed to fungicide vinclozolin by suppression subtractive hybridization

Vinclozolin, a dicarboximide fungicide, is an endocrine disrupting chemical that competes with an androgenic endocrine disruptor compound. Most research has focused on the epigenetic effect of vinclozolin in humans. In terms of ecotoxicology, understanding the effect of vinclozolin on non-target organisms is important. The expression profile of a comprehensive set of genes in the amphipod Hyalella azteca exposed to vinclozolin was examined. The expressed sequence tags in low-dose vinclozolin-treated and -untreated amphipods were isolated and identified by suppression subtractive hybridization. DNA dot blotting was used to confirm the results and establish a subtracted cDNA library for comparing all differentially expressed sequences with and without vinclozolin treatment. In total, 494 differentially expressed genes, including hemocyanin, heatshock protein, cytochrome, cytochrome oxidase and NADH dehydrogenase were detected. Hemocyanin was the most abundant gene. DNA dot blotting revealed 55 genes with significant differential expression. These genes included larval serum protein 1 alpha, E3 ubiquitin-protein ligase, mitochondrial cytochrome c oxidase, mitochondrial protein, proteasome inhibitor, hemocyanin, zinc-finger–containing protein, mitochondrial NADH-ubiquinone oxidoreductase and epididymal sperm-binding protein. Vinclozolin appears to upregulate stress-related genes and hemocyanin, related to immunity. Moreover, vinclozolin downregulated NADH dehydrogenase, related to respiration. Thus, even a non-lethal concentration of vinclozolin still has an effect at the genetic level in H. azteca and presents a potential risk, especially as it would affect non-target organism hormone metabolism.     

Environmental fate of pesticides used in Australian viticulture: Behaviour of dithianon and vinclozolin in the soils of the South Australian Riverland

The red calcareous earth soils of the South Australian Riverland produce more than one-third of the grapes used in Australian winemaking. As part of on-going investigations into pesticide transport in Australian vineyard soils, the movement of the fungicides dithianon and vinclozolin through such strongly alkaline soils was investigated. Small, undisturbed soil cores were extracted from the inter-row topsoil of a vineyard adjacent to the River Murray, approximately 10 km S.W. of Overland Corner, South Australia. The vines were grown in a deep (1 – 4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (1 – 2 %). Surface fluxes of pesticide were applied at the maximum recommended application rates to the surface of the cores, which were then irrigated, and pesticide residues in the leachate determined by HPLC. No leaching of either dithianon or vinclozolin occurred. Dithianon was immobilised in the top 2 cm of the soil. Dithianon concentrations were low ( 0 – 37 % applied dose) suggesting that rapid degradation of this compound occurs in these soils (63 – 100 % degradation in 10 days). Extremely low concentrations of vinclozolin were found throughout the soil core profiles (0.05 – 1.4 % applied dose) suggesting that this fungicide was somewhat mobile, but also that it too was unstable in such alkaline soils (> 98 % degradation in 10 days). These results suggest that the irrigated vineyard soils of this region are unlikely to be prone to leaching of dithianon or vinclozolin, and therefore that groundwater supplies in this area are unlikely to be at any significant risk of contamination through viticultural use of these compounds.     

环境激素烯菌酮引发小鼠前列腺癌细胞的毒性机制

为探讨环境激素烯菌酮引发小鼠前列腺癌(RM-1)细胞毒性机制,设计了3组实验,分别为对照组、烯菌酮染毒组(染毒组)和烯菌酮染毒后添加维生素E组(实验组),各组给药培养48h后,观察细胞形态变化。检测细胞增殖活性、丙二醛(MDA)含量、抑制羟自由基能力、乳酸脱氢酶(LDH)活性、Na+-K+-ATP酶活性和Ca2+-Mg2+-ATP酶活性。结果表明,与对照组相比,染毒组RM-1细胞圆缩脱落明显,贴壁细胞减少;细胞增殖率、抑制羟自由基能力、Na+-K+-ATP酶活性和Ca2+-Mg2+-ATP酶活性明显降低(p<0.05),LDH活性和MDA含量显著升高(p<0.05)。与染毒组相比,染毒后添加维生素E,圆缩脱落细胞减少,而梭形贴壁细胞明显增加;细胞增殖率、抑制羟自由基能力、Na+-K+-ATP酶活性和Ca2+-Mg2+-ATP酶活性显著升高(p<0.05),LDH活性和MDA含量明显下降(p<0.05)。这表明维生素E可能通过其抗氧化性拮抗了烯菌酮引发的氧化应激,缓解了细胞膜的损伤,维持了细胞膜的完整性和膜蛋白的功能,防止了细胞内LDH外逸、Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶活性的下降,从而逆转了烯菌酮引发的细胞死亡和增殖率的下降。     

乙烯菌核利对稀有鮈鲫性腺组织及相关基因转录水平的影响

乙烯菌核利在哺乳动物实验中被广泛证实具有抗雄激素效应,而对鱼类的研究结论目前并不统一。将性成熟稀有鮈鲫分别暴露于0、2、10、50μg·L-1乙烯菌核利21 d,研究环境浓度下乙烯菌核利对鱼类生殖系统的影响及作用机制。结果表明,雌鱼的性腺指数(GSI)、肝脏指数(HSI)在所有浓度组均显著降低(p0.05),同时卵巢组织中卵泡的发育受到了抑制;而雄鱼仅HSI在最高浓度组(50μg·L-1)出现显著降低(p0.05),精巢组织切片也未观察到明显损伤,说明乙烯菌核利对雌鱼生殖系统的影响大于雄鱼。在转录水平上,雌鱼性腺中er mRNA、vtg mRNA分别在50μg·L-1和10、50μg·L-1时显著升高(p0.05),ar mRNA在所有浓度组显著升高(p0.05);而雄鱼性腺中ar mRNA、dmrt1 mRNA水平分别在10μg·L-1浓度组和所有浓度组显著降低(p0.05),er mRNA在所有浓度组显著降低(p0.05),说明雌雄鱼对乙烯菌核利暴露的分子响应机制存在差异。综上,环境浓度下乙烯菌核利短期暴露会对稀有鮈鲫生殖系统产生一定的影响,并且雌雄鱼在敏感性和分子响应机制上都存在差异。     

Selected endocrine disrupting compounds (Vinclozolin,Flutamide, Ketoconazole and Dicofol): Effects on survival,occurrence of males,growth, molting and reproduction of <Emphasis Type="Italic">Daphnia magna</Emphasis>

BACKGROUND, AIM AND SCOPE: Pollution-induced endocrine disruption in vertebrates and invertebrates is a worldwide environmental problem, but relatively little is known about effects of endocrine disrupting compounds (EDCs) in planktonic crustaceans (including Daphnia magna). Aims of the present study were to investigate acute 48 h toxicity and sub-chronic (4-6 days) and chronic (21 days) effects of selected EDCs in D. magna. We have investigated both traditional endpoints as well as other parameters such as sex determination, maturation, molting or embryogenesis in order to evaluate the sensitivity and possible use of these endpoints in ecological risk assessment. MATERIALS AND METHODS: We have studied effects of four model EDCs (vinclozolin, flutamide, ketoconazole and dicofol) on D. magna using (i) an acute 48 h immobilization assay, (ii) a sub-chronic, 4-6 day assay evaluating development and the sex ratio of neonates, and (iii) a chronic, 21 day assay studying number of neonates, sex of neonates, molting frequency, day of maturation and the growth of maternal organisms. RESULTS: Acute EC50 values in the 48 h immobilization test were as follows (mg/L): dicofol 0.2, ketoconazole 1.5, flutamide 2.7, vinclozolin >3. Short-term, 4-6 day assays with sublethal concentrations showed that the sex ratio in Daphnia was modulated by vinclozolin (decreased number of neonate males at 1 mg/L) and dicofol (increase in males at 0.1 mg/L). Flutamide (up to 1 mg/L) had no effect on the sex of neonates, but inhibited embryonic development at certain stages during chronic assay, resulting in abortions. Ketoconazole had no significant effects on the studied processes up to 1 mg/L. DISCUSSION: Sex ratio modulations by some chemicals (vinclozolin and dicofol) corresponded to the known action of these compounds in vertebrates (i.e. anti-androgenicity and anti-oestrogenicity, respectively). Our study revealed that some chemicals known to affect steroid-regulated processes in vertebrates can also affect sublethal endpoints (e.g. embryonic sex determination and/or reproduction) in invertebrates such as D. magna. CONCLUSIONS: A series of model vertebrate endocrine disrupters affected various sub-chronic and chronic parameters in D. magna including several endpoints that have not been previously studied in detail (such as sex determination in neonates, embryogenesis, molting and maturation). Evaluations of traditional reproduction parameters (obtained from the 21 day chronic assay). as well as the results from a rapid, 4-6 day, sub-chronic assay provide complementary information on non-lethal effects of suspected organic endocrine disrupters. RECOMMENDATIONS AND PERSPECTIVES: It seems that there are analogies between vertebrates and invertebrates in toxicity mechanisms and in vivo effects of endocrine disruptors. However, general physiological status of organisms may also indirectly affect endpoints that are traditionally considered 'hormone regulated' (especially at higher effective concentrations as observed in this study) and these factors should be carefully considered. Further research of D. magna physiology and comparative studies with various EDCs will help to understand mechanisms of action as well as ecological risks of EDCs in the environment.