官厅水库水体中微囊藻毒素及其与微囊藻细胞密度相关性研究

2004-2005年对连年发生比较严重水华的官厅水库进行了2 a的浮游植物动态监测,并在2005年6-8月应用酶联免疫吸附法检测了主要水华藻类--铜绿微囊藻藻毒素质量浓度及其季节变化,初步探讨了微囊藻毒素质量浓度与铜绿微囊藻细胞密度之间的关系.实验结果表明,水库中的浮游植物细胞密度高,2004年平均值为1 308.35×104 cells/L,2005年达1 599.49×104 cells/L,同时呈现出明显的季节变化,在夏末秋初形成高峰.产毒的铜绿微囊藻为夏季最主要的优势水华种类,其细胞密度在7月达到最高,为4 748.58×104 cells/L;微囊藻毒素的质量浓度在7月亦达到最高值,为20 μg/L,都显著高于6月和8月(p＜0.05).水体中微囊藻毒素质量浓度与微囊藻细胞密度呈正相关关系(R=0.926).其结果为全面了解官厅水库水质状况以及对水污染进行治理,恢复其饮用水源的功能提供了科学依据.     

Lack of genotoxic potential of permethrin in mice evaluated by the comet assay and micronucleus test

Permethrin is a common insecticide that does not show genotoxic potential in standard in vitro and in vivo assays. To investigate the genotoxic potential of permethrin in more detail, two in vivo studies were conducted on female mice to assess DNA damage in tumor target organs by the comet assay and micronucleus test. For this, mice were administered permethrin at doses of 150, 300, or 600 mg/kg/day by gavage for 2 days, and their lung, liver, glandular stomach, peripheral blood, and bone marrow cells were examined for DNA damage. There were no significant increases in % tail DNA in the organs examined and no increase in micronuclei in peripheral blood by flow cytometry. Taken together, the present findings provide evidence that permethrin has no genotoxic, aneugenic, or clastogenic potential.     

纳米银和PVP包被纳米银对HepG2细胞遗传毒性的比较研究

为了探讨纳米银对HepG2细胞DNA损伤、染色体畸变等遗传毒性指标的影响,以期为纳米银体外遗传毒性评价提供参考依据,本文采用2种纳米银材料(20 nm-PVP包被纳米银、20 nm-无包被纳米银),分别以20μg·mL~(-1)、40μg·mL~(-1)、80μg·mL~(-1)、160μg·mL~(-1)的剂量对HepG2细胞染毒24 h,用Hoechst-33258染色法检测细胞凋亡,彗星实验检测DNA损伤,胞质分裂阻滞微核细胞组学试验法检测染色体畸变。结果表明,20 nm Ag NPs组在160μg·mL~(-1)时引起细胞凋亡数显著增多(P0.05);20 nm PVP-Ag NPs组在80μg·mL~(-1)和160μg·mL~(-1)剂量组中细胞凋亡数显著增多(P0.01)。2种纳米银引起HepG2细胞发生细胞凋亡,并呈剂量效应关系。彗星试验结果表明,20 nm Ag NPs和20 nm PVP-Ag NPs在40μg·mL~(-1)、80μg·mL~(-1)、160μg·mL~(-1)剂量组中,Olive尾矩、尾长和尾部DNA百分比与空白对照组相比均有显著差异(P0.05)。2种纳米银对HepG2细胞DNA损伤程度为:20 nm Ag NPs20 nm PVP-Ag NPs。胞质分裂阻滞微核细胞组学试验结果表明,2种纳米银均不会引起核质桥数发生明显改变(P0.05),20 nm Ag NPs在高染毒剂量下引起微核总数、I型微核、II型微核、核芽数明显升高(P0.05);20 nm PVP-Ag NPs在各染毒剂量下均会引起微核总数及I型微核数量升高(P0.01),II型微核数在160μg·mL~(-1)剂量下升高明显(P0.01),剂量大于20μg·mL~(-1)时核芽数升高(P0.01)。20 nm PVP-Ag NPs对细胞核的影响大于20 nm Ag NPs(P0.05)。总之,2种纳米银材料均会引起HepG2细胞DNA损伤及染色体畸变等遗传毒性效应的改变,无包被纳米银比PVP包被纳米银更容易引起DNA损伤,PVP包被纳米银比无包被纳米银更容易引起细胞染色体畸变相关效应;2种材料对HepG2细胞的损伤存在浓度-效应关系,浓度越高遗传毒性损伤越严重。     

Lead toxicity thresholds in 17 Chinese soils based on substrate-induced nitrification assay

The influence of soil properties on toxicity threshold values for Pb toward soil microbial processes is poorly recognized. The impact of leaching on the Pb threshold has not been assessed systematically. Lead toxicity was screened in 17 Chinese soils using a substrate-induced nitrification (SIN) assay under both leached and unleached conditions. The effective concentration of added Pb causing 50% inhibition (EC50) ranged from 185 to > 2515 mg/kg soil for leached soil and 130 to > 2490 mg/kg soil for unleached soil. These results represented > 13- and > 19-fold variations among leached and unleached soils, respectively. Leaching significantly reduced Pb toxicity for 70% of both alkaline and acidic soils tested, with an average leaching factor of 3.0. Soil pH and CEC were the two most useful predictors of Pb toxicity in soils, explaining over 90% of variance in the unleached EC50 value. The relationships established in the present study predicted Pb toxicity within a factor of two of measured values. These relationships between Pb toxicity and soil properties could be used to establish site-specific guidance on Pb toxicity thresholds.     

Genotoxicity evaluation of drinking water sources in human peripheral blood lymphocytes using the comet assay

The potential harm of organic pollutants in drinking water to human health is widely focused on in the wodd; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source samples were collected from 7 different localities of Nanjing City. The potential genotoxicity of organic extracts from drinking water sources were investigated by means of the comet assay in human peripheral lymphocytes. The results showed that all the organic extracts from all the water source samples could induce DNA damages of human peripheral blood lymphocytes at different levels. A significant difference （P 〈 0.01） was observed when compared with the solvent control, The DNA damage increased with the increase of the dosage of the original water source. Significant differences of DNA damage were observed in different drinking water sources, as shown by the multiple comparisons analysis at the dosage of 100x; the degree of DNA damage treated by Hushu waterworks （at town level） was the most serious, the arbitrary units （AU） was 141.62±6.96, however, that of Shangyuanmen waterworks （at city level） was only 109.64±2.97. The analysis also revealed that the genotoxicity of town＇s water sources was higher than that of the city. The results demonstrated that the comet assay can be successfully applied to the genotoxicity monitoring programs of drinking water sources.     

Detection of Phaeocystis globosa using sandwich hybridization integrated with nuclease protection assay (NPA-SH)

Phaeocystis globosa Scherffel is one of the common harmful algae species in coastal waters of the southeastern China. In this study, sandwich hybridization integrated with nuclease protection assay (NPA-SH) was used to qualitatively and quantitatively detect P. globosa. Results showed that this method had good applicability and validity in analyzing the samples from laboratory cultures and from fields. The linear regression equation for P. globosa was obtained, and the lowest detection number of cells was 1.8 × 10⁴ cells. Statistics showed that there was no distinct difference between the results of detecting the microalgae by NPA-SH and traditional microscopy. This technique has good reliability, accuracy, and can give a remarkably high sample processing rate. Sandwich hybridization integrated with nuclease protection assay will provide an efficient alternative to microscopic method for monitoring and investigating the bloom of P. globosa.     

新型淡水发光菌(Vibrio qinghaiensis sp.——Q67)应用于环境样品毒性测试的初步研究

研究表明，新型淡水发光菌作为环境样品毒性检验的指标生物具有快速简便的优点。对重金属物毒性检验比以往Ｔ３发光菌具有更高的灵敏度，对鱼体进行的感染实验未发现明显病理改变。     

Genotoxicity of gold nanoparticles functionalized with indolicidin towards Saccharomyces cerevisiae

The toxic effects of gold nanoparticles surface-functionalized with the antimicrobial peptide indolicidin(Au NPs-indolicidin) towards the yeast Saccharomyces cerevisiae, one of the major eukaryotic model organisms, have been evaluated. Growth and survival,genotoxicity, as measured by comet assay, and expression of the YCA1, an apoptosis indicating gene, following 72 hr exposure of yeast to Au NPs-indolicidin, and to Au NPs and indolicidin alone have been examined. The gold nanoparticles exerted toxicity with DNA damage, accompanied by reactive oxygen species production(ROS), but they do not inhibit yeast growth and viability. Genotoxicity was less pronounced for surface-functionalized nanoparticles, showing that S. cerevisiae is quite resistant to the complex Au NPs-indolicidin.A progressive reduction of the genotoxic effect was observed along 72 hr exposure,presumably due to the activation of DNA repair mechanisms. These findings suggest the occurrence of a physiological protective response of S. cerevisiae towards nanoparticles,thereby providing useful information to the assessment of the environmental impact of metal nanoparticles.     

A hydroxyl radical detection system using gas expansion and fast gating laser-induced fluorescence techniques

An OH radical measurement instrument based on Fluorescence Assay by Gas Expansion(FAGE)has been developed in our laboratory.Ambient air is introduced into a low-pressure fluorescence cell through a pinhole aperture and irradiated by a dye laser at a high repetition rate of 8.5 k Hz.The OH radical is both excited and detected at 308 nm using A-X(0,0)band.To satisfy the high efficiency needs of fluorescence collection and detection,a 4-lens optical system and a self-designed gated photomultiplier(PMT)is used,and gating is actualized by switching the voltage applied on the PMT dynodes.A micro channel photomultiplier(MCP)is also prepared for fluorescence detection.Then the weak signal is accumulated by a photon counter in a specific timing.The OH radical excitation spectrum range in the wavelength of 307.82–308.2 nm is detected and the excited line for OH detection is determined to be Q_1(2)line.The calibration of the FAGE system is researched by using simultaneous photolysis of H_2O and O_2.The minimum detection limit of the instrument using gated PMT is determined to be 9.4×10~5molecules/cm~3,and the sensitivity is 9.5×10~(-7)cps/(OH·cm~(-3)),with a signal-to-noise ratio of 2 and an integration time of 60 sec,while OH detection limit and the detection sensitivity using MCP is calculated to be 1.6×10~5molecules/cm~3and 2.3×10~(-6)cps/(OH·cm~(-3)).The laboratory OH radical measurement is carried out and results show that the proposed system can be used for atmospheric OH radical measurement.     

Antioxidant and modulatory role of Chlorophytum borivilianum against arsenic induced testicular impairment

Arsenic has a suppressive influence on spermatogenesis and induces impairment in male reproductive system due to oxidative stress. The present study was aimed to test the arsenic induced toxicity and protection by Chlorophytum borivilianum. The effect of sodium arsenite (4 mg/(kg body weight (bw). day)) via double distilled water without or with C. borivilianum (800 mg/(kg bw. day)) was evaluated in Swiss albino mice for 30 days. The radical scavenging activity of the aqueous C. borivilianum root extract was measured using DPPH (1,1-diphenyl-2-picryl hydrayzyl) radical. Qualitative assessment of various cell types in the testis, sperm count and motility, testicular activity of lipid peroxidation (LPO), reduced glutathione (GSH), acid and alkaline phosphatase, cholesterol and serum testosterone were monitored. Arsenic treatment showed a significant increase in LPO, acid and alkaline phosphatase, cholesterol and decrease in sperm count, sperm motility, GSH and serum testosterone. Combined treatment showed significant decrease in LPO, acid and alkaline phosphatase, cholesterol and elevation in sperm count, sperm motility, GSH and serum testosterone. Testicular histopathology showed that C. borivilianum had reduced degeneration of germ cell in the seminiferous tubules and loss of sperms induced by arsenic intoxication. The results thus led us to conclude that administration of C. borivilianum root extract is found to be protective against arsenic induced toxicity.