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591.
In this study, different concentrations of five food dyes (amaranth, patent blue, carminic acid, indigotine and erythrosine) have been evaluated for genotoxicity in the Somatic Mutation and Recombination Test (SMART) of Drosophila melanogaster. Standard cross was used in the experiment. Larvae including two linked recessive wing hair mutations were chronically fed at different concentrations of the test compounds in standard Drosophila Instant Medium. Feeding ended with pupation of the surviving larvae. Wings of the emerging adult flies were scored for the presence of spots of mutant cells which can result from either somatic mutation or somatic recombination. For the evaluation of genotoxic effects, the frequencies of spots per wing in the treated series were compared to the control group, which was distilled water. The present study shows that carminic acid and indigotine demonstrated negative results while erythrosine demonstrated inconclusive results. In addition 25 mg mL−1 concentration of patent blue and 12.5, 25 and 50 mg mL−1 concentrations of amaranth demonstrated positive results in the SMART. 相似文献
592.
Inhibition of gap junctional intercellular communication (GJIC) is affiliated with tumor promotion process and it has been employed as an in vitro biomarker for evaluation of tumor promoting effects of chemicals. In the present study we investigated combined effects of anthropogenic environmental contaminants 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153) and fluoranthene, cyanotoxins microcystin-LR and cylindrospermopsin, and extracts of laboratory cultures of cyanobacteria Aphanizomenon gracile and Cylindrospermopsis raciborskii, on GJIC in the rat liver epithelial cell line WB-F344. Binary mixtures of PCB 153 with fluoranthene and the mixtures of the two cyanobacterial strains elicited simple additive effects on GJIC after 30 min exposure, whereas microcystin-LR and cylindrospermopsin neither inhibited GJIC nor altered effects of PCB 153 or fluoranthene. However, synergistic effects were observed in the cells exposed to binary mixtures of anthropogenic contaminants (PCB 153 or fluoranthene) and cyanobacterial extracts. The synergistic effects were especially pronounced after prolonged (6-24 h) co-exposure to fluoranthene and A. gracile extract, when mixture caused nearly complete GJIC inhibition, while none of the individual components caused any downregulation of GJIC at the same concentration and exposure time. The effects of cyanobacterial extracts were independent of microcystin-LR or cylindrospermopsin, which were not detected in cyanobacterial biomass. It provides further evidence on the presence of unknown tumor promoting metabolites in cyanobacteria. Clear potentiation of the GJIC inhibition observed in the mixtures of two anthropogenic contaminants and cyanobacteria highlight the importance of combined toxic effects of chemicals in complex environmental mixtures. 相似文献
593.
分子筛固载Fe2+-Fenton法降解水中甲基橙的研究 总被引:12,自引:1,他引:12
单因素实验考察了不同Fe2+负载量、甲基橙溶液初始浓度、温度、催化剂用量、pH值以及H2O2浓度对降解率的影响。正交实验优化了降解反应条件,得出各因素影响显著性的先后顺序为:pH值、温度、反应时间、催化剂用量、H2O2浓度。结果表明:在常压、温度为35℃,起始pH值为3.00、H2O2浓度为0.552mmol/L、催化剂浓度为0.83g/L、反应时间为80min的最佳条件下,甲基橙降解率可达98.15%。对催化剂进行了紫外照射处理回收再生,功率100W条件下,照射3h后再生催化剂活性可达原来的80.64%。 相似文献
594.
旱作小麦─玉米垅种沟盖地膜带田集水调水与增产效应研究 总被引:6,自引:0,他引:6
旱作垅种(小麦)沟盖(玉米)地膜带田优于目前推广的沟种(小麦)垅盖(玉米)带田种植形式。在作物共生期相互调水作用更趋合理,平衡了小麦、玉米不同生育阶段对水分的供需矛盾,作物的生态条件更加适宜,群体结构更加协调,提高了作物的生产量,前者比后者增产90%~125%。 相似文献
595.
KONG Woo-seok 《环境科学学报(英文版)》1999,11(2):243-246
1IntroductionDuetotherapidglobalwarmingtrend,whichtookplaceinthe20thcentury,numerousunexpectedenvironmentalandecologicalisues... 相似文献
596.
597.
We report a study which examined whether the decision of 135 couples to accept prenatal cystic fibrosis (CF) carrier screening would be influenced by the advent of gene therapy. A majority (91 couples; 67 per cent) felt that gene therapy for CF would not influence their decision to be screened. Twenty-two couples (16 per cent) stated that they would decline to be screened and an equal number felt ambivalent. Even if the life expectancy of a CF sufferer were increased by gene therapy to normal, 78 per cent of couples would still wish to avail themselves of prenatal carrier screening. A majority of women who decline screening do so because they are opposed to termination of pregnancy. The availability of gene therapy could increase the proportion of couples who accept screening. 相似文献
598.
以我国典型淡水水华藻种铜绿微囊藻(Microcystis aeruginosa905)为研究对象,采用推流式低压紫外灯反应器研究在动态条件下Ultraviolet-C(UV-C)辐照对蓝藻生长抑制作用的效果.对数培养期的蓝藻液流经反应器进行UV-C辐照处理,其后正常培养,在培养期2 h、1 d、3 d、5 d、7 d、9 d分别取样,通过研究级倒置荧光显微镜在荧光视野下进行细胞计数.结果表明,辐照处理未引起铜绿微囊藻细胞的大量破裂死亡,36~115 mW.s.cm-2剂量范围的UV-C辐照能在9 d内有效抑制2.6×105~2.7×105cells.mL-1的铜绿微囊藻细胞密度增长,31~50 mW.s.cm-2剂量范围的UV-C辐照能在9d内有效抑制9.0×105~1.15×106cells.mL-1的铜绿微囊藻细胞密度增长. 相似文献
599.
600.
阶地古红土在华南分布很广,是一项重要资源。本文以钱塘江中下游为例,查明:阶地古红土分布决定于局部新构造运动升沉量与构造断块活动;愈到下游,古红土土层愈厚;在每一地段,阶地愈高,红壤化作用愈深,表现在铁的活化度(Feo/Fed)减低,粘粒的 SiO2/Al2O3变小,酸性与粘性增强等。按新构造运动抬升时间与幅度,古红土还可划分为Q2与Q3两类,其上土壤的理化性质、作物的适种性及开发条件都不相同。二者的面积比(Q2/Q3)则与各区域新构造运动特点有关。 相似文献