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1.
采用AM1方法计算了环境致癌1,3-丁二烯的代谢物产1,2-环境氧-3,4-丁烯和1,2,3,4-二环氧化烷与DNA腺嘌呤和胞嘧啶烷化反应过程速率控制步骤的活化能,以及DEB和DNA大沟侧与不同序列DNA片断生成烷化股间横向联 产物的结构和能量。 相似文献
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采用AM1方法计算了6个α-二羰基化合物与DNA碱基岛嘌呤环外N^2发生紊电加成反应的速率控制步骤的活化能及分子结构和电子结构。研究其结构-知必凶线性回归结果表明;可用烷化反应活化能、LUMO能量、分子量表面积比和羰基面原子的正电性表示化合物的致突活性指数,获得很好的回归效果(L顺归系数R=0.9998)。以本文提出的方程对这些化合物的估性进行计算,秘得到的结果与实验结果吻合得很好。 相似文献
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研究了铬(Ⅳ)-2,4-二氯苯基荧光酮(DCIPE)-溴化十六烷基三甲胺(CTMAB)体系的显色条件,试验结果表明,在pH5.2~7.0范围内,铬与DCIPF及CTMAB形成红色三元胶束配合物,其最大吸收波长为578nm,表现摩尔吸光系数为1.40×10^5I.mol^-1.cm^-1,铬(Ⅵ)含量在0~9.0μg/25ml范围内符合比耳定律,配合物的组成为Cr(Ⅵ):DCIPF=1:2,拟定方法 相似文献
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六种重金属对大肠杆菌体内质粒DNA一级结构的影响 总被引:6,自引:0,他引:6
将质粒pBR322、c-Myc、pC53-SN3、pTB29转入大肠杆菌(Escherichiacoli)HB101中使其各自分别在含亚致死浓度Pb2+、Cd2-、Zn2+、Cu2+、Mn2+、Hg2+的液体氨苄LB培养基中,振荡培养24h后,再将这些质粒抽提出来,通过限制性内切酶分析,研究了这些重金属离子对大肠杆菌体内质粒DNA分子一级结构的影响。结果表明,在供试的6种重金属离子中只有Hg2+处理可明显导致质粒DNA序列的改变。此外,供试6种重金属离子连续处理24h未发现可明显导致大肠杆菌体内质粒DNA链的随机断裂。 相似文献
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Ellen G. Pfendner Aoi Nakano Leena Pulkkinen Angela M. Christiano Jouni Uitto 《黑龙江环境通报》2003,23(6):447-456
Epidermolysis bullosa (EB) is a group of inherited disorders characterized by increased skin fragility, resulting in blisters and erosions after minor trauma. Mutations in 10 structural genes expressed in the cutaneous basement membrane zone have been reported. The DebRA Molecular Diagnostics Laboratory at Jefferson Medical College has performed 144 DNA-based prenatal diagnoses since 1993 in families at risk for recurrence of the most severe forms of EB, including the recessive dystrophic EB (RDEB), junctional EB (JEB), EB with pyloric atresia (EB-PA), and EB simplex (EBS). A mutation-detection strategy using either conformation-sensitive gel electrophoresis (CSGE) or denaturing high-performance liquid chromatography (dHPLC) scanning analysis, followed by nucleotide sequencing, was applied to most cases with DEB and to all JEB, EB-PA, and EBS families. For some RDEB families, linkage analysis was performed, either alone when the inheritance pattern was clear or in combination with one mutation. Among the 144 prenatal diagnoses, 63 were for RDEB, 69 for JEB, 6 for EB-PA, and 6 for EBS. Twenty-eight normal, 73 heterozygous carrier, and 28 affected RDEB, JEB, and EB-PA pregnancies were reported in these recessively inherited diseases. Two affected and four normal pregnancies were predicted in dominantly inherited EBS. Among the 144 pregnancies, 9 were terminated without confirmation, 13 cases were lost to follow-up, and 6 pregnancies are ongoing. There were 6 families with inconclusive results due either to recombination events between flanking markers, absence of informative markers for one allele, or lack of sample from the previously affected child. There were three discordant results, one that was explained by maternal contamination of the chorionic villus sample and two that were unresolved. Overall, the availability, relative ease, and over 98% success rate make molecular DNA-based prenatal diagnosis a viable option for EB families at risk. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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为了探讨甲醛暴露对小鼠骨髓组织的毒性影响,选用SPF级昆明雄性小鼠作为研究对象,用浓度为0.5,1.0,3.0mg/m3的气态甲醛对小鼠进行连续动态染毒72h,染毒后检测骨髓细胞中细胞周期变化、DPC(DNA-蛋白质交联)、DNA稳定性、骨髓细胞分化关键因子Nucleostemin和CYP1B1在各暴露浓度组中的表达情况.结果表明:甲醛暴露造成骨髓细胞的DNA损伤,其DNA稳定性和DPC效应均呈现良好的剂量-效应关系.骨髓细胞分化关键因子Nucleostemin表达量在各浓度染毒组中与空白组相比,1.0mg/m3浓度组有极显著性升高,而0.5和3.0mg/m3浓度组则是极显著性降低,与空白组相比CYP1B1基因在0.5,1.0,3.0mg/m3浓度组中表达,有极其显著性差异,并且1.0mg/m3浓度组上升较多.本次研究表明,甲醛暴露能影响小鼠骨髓组织细胞正常生长代谢. 相似文献
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Chengrun Wang Kegui Zhang Mei He Chuanjun Jiang Liumin Tian Yuan Tian Xiaorong Wang 《环境科学学报(英文版)》2012,24(2):214-220
Effects of mineral nutrient imbalance, DNA lesion and DNA-protein crosslink on growth of Vicia faba L. seedlings hydroponically cultivated in concentrations of extraneous lanthanum (La) for 20 days were investigated in the present experiment. The results showed that contents of La, Cu or K elements in roots generally changed synchronously with those in leaves, while Ca, Fe, Zn, Mg, Mn or P in the roots altered inversely to those in the leaves. Thus, the extraneous La led to redistribution and imbalance of mineral nutrient elements in the roots and leaves. DNA lesion and DNA-protein crosslink were investigated by single cell gel electrophoresis (SCGE) and sodium dodecyl sulfate/potassium (SDS/K+) precipitation methods, respectively. The results demonstrated that the increasing La induced DNA break and DNA-protein crosslinks (DPCs) in the seedlings. These results suggested that mineral nutrient imbalance, DNA lesion and DNA-protein crosslink were involved in the growth retardation and growth alteration of the seedlings, which may help to understand the mechanisms of rare earth elements (REEs) on plant growth. 相似文献
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Jo-David Fine M.D. Karen A. Holbrook Sherman Elias Ingrun Anton-Lamprecht Rüdiger Rauskolb 《黑龙江环境通报》1990,10(4):219-229
Recently a monoclonal antibody (19–DEJ-l) was produced with binding specificity for the mid-lamina lucida of the skin dermoepidermal junction, in very close association with overlying hemidesmosomes. Since skin cleavage occurs within the lamina lucida in the inherited blistering disorder, junctional epidermolysis bullosa (EB), and is associated with aberrations in the morphology and/or number of hemidesmosomes in such tissue, we have sought to determine whether this monoclonal antibody could be used for prenatal diagnosis. Fetoscopy-directed skin biopsies were obtained from two fetuses at risk for junctional EB and post-mortem samples from two other fetuses with the Herlitz type of junctional EB, the latter after prenatal diagnosis by electron microscopy and termination of each pregnancy. Specimens were examined in part by light and electron microscopy for evidence of skin cleavage or other alterations in morphology, and in part by indirect immunofluorescence for altered basement membrane antigenicity. Three of four fetuses were shown to have intra-lamina lucida blister formation indicative of, and hemidesmosome hypoplasia proving, junctional EB. Each was also shown to lack expression of GB3 and 19–DEJ-l antigens, consistent with findings noted postnatally in junctional EB; diagnosis was confirmed in each at the time of therapeutic abortion. A fourth fetus had no abnormalities detected; lack of disease involvement was confirmed at the time of delivery, and subsequently over 8 months of careful serial evaluation. We conclude that 19–DEJ-l monoclonal antibody is an accurate and sensitive irnmunohistochemical probe for junctional EB, and may be employed in the prenatal diagnostic evaluation of fetuses at risk for this disorder. 相似文献
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在两性修饰剂十二烷基二甲基甜菜碱(BS)修饰膨润土的基础上,采用双子型阳离子修饰剂乙撑基双十四烷基二甲基氯化铵(EB)对其进行复配修饰,以批处理法研究了不同修饰比例、温度、pH值和离子强度条件下,BS+EB复配修饰膨润土对Cr(VI)的吸附规律和热力学特征,并通过吸附Cr(VI)前后BS+EB复配修饰膨润土的红外光谱和表面电荷探讨了其吸附机制.结果表明,与BS两性修饰膨润土比较,EB复配修饰显著增强了其对Cr(VI)的吸附能力,吸附量增加了2.02~27.25倍,30℃时吸附量呈现BS+150EB(BS和150%比例的EB复配修饰膨润土) > BS+100EB > BS+50EB > BS+25EB > BS > CK(膨润土)的趋势,对Cr(VI)的吸附量随EB修饰比例增加而上升.CK、BS修饰膨润土对Cr(VI)呈现自发、熵增和焓增的特征,而BS+EB复配修饰膨润土对Cr(VI)吸附量随着温度的升高而降低,呈现出增温负效应.随着pH值的升高、离子强度增加,各供试土样对Cr(VI)的吸附量逐渐降低.红外光谱和土壤表面电荷结果证实电荷引力是BS+EB复配修饰土吸附Cr(VI)的主要机制. 相似文献
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PCR-DGGE技术在城市污水化学生物絮凝处理中的特点 总被引:24,自引:4,他引:20
通过PCR-DGGE等分子生物学技术可以不经过常规培养直接从活性污泥和生物膜样品中提取DNA,对16Sr DNA V3区进行PCR扩增,结合DGGE(变性梯度凝胶电泳),从而分析活性污泥与生物膜中微生物种群结构.研究证实,活性污泥培养前后微生物种群结构发生很大的改变.同时对2种污水处理工艺中微生物种群结构进行了对比研究,对同一反应器不同位置微生物分布以及不同工况下的微生物种群结构进行了初步探讨.测定了活性污泥中部分菌种的16S rDNA V3区片段序列,通过NCBI(美国国立生物技术信息中心)基因库比对,初步确定细菌的属.结果显示,PCR-DGGE结合测序技术是一种完全可行的快速进行环境学样品微生物研究的分析方法. 相似文献
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Interaction of DNA with aromatic hydrocarbons fraction in atmospheric
particulates of Xigu District of Lanzhou, China 总被引:1,自引:0,他引:1
Voluminously epidemiological studies show that the relationships exist between the air pollution and human health and cancer. Aromatic hydrocarbons(AHs)in air form a large class of organic pollutants,which are widely in environment and many of them are known to be carcinogenic and/or mutagenic and contribute to ambient air pollution.In the past decades,bioassays mainly have been used to evaluate the toxicity of chemical mixtures in atmospheric particulates or aqueous environment.However,it is well known that the covalent complexes formed by carcinogens with DNA may be exert negative results in bioassay.So the main aim of this paper is to develop an evaluation method of toxicity effects of chemical mixtures in atmospheric particulates from chemical standpoint.In this study,the in vitro interaction of the AHs with DNA was investigated by absorption,fluorescence and resonance light scattering (RLS)spectroscopic techniques.The results showed that the AHs in the atmospheric particulates could combine with calf thymus DNA(ctDNA)and herring sperm DNA(hsDNA)without being activated or metabolized by organism,respectively.Intercalation may be present in the mechanism of interaction.The binding constants of the AHs with ctDNA and hsDNA were 2.5×10~2 and 2.0×10~3, respectively,which indicated that the interaction of the AHs with hsDNA is stronger than that with ctDNA.In addition,the relationships of dose-effect between the total mole concentration of chemical components and the ability of binding ctDNA and hsDNA were confirmed.This research made it possible to study the toxicity effects of chemical mixtures in atmospheric particulates by chemical method.It is believed that the composition and contents of unknown AHs and the interaction of DNA with AHs in atmospheric particulates of Xigu District of Lanzhou City,China are first reported in the past twenty years. 相似文献
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采用盐雾和紫外-冷凝室内人工加速老化循环试验的方法,对聚氨酯和丙烯酸两种典型的船壳涂料进行人工加速老化试验。采用傅利叶红外漫反射光谱(FDIR)、扫描电子显微镜(SEM)及原子力显微扫描电镜(AFM)等现代测试分析手段,对各试验周期的结果进行检测和表征。结合其它表面分析技术测试涂层表面失光、色差等变化,对聚氨酯、丙烯酸这两种常用典型船壳涂层的老化性能进行研究,探索室内加速试验的方法和条件,为实验室加速试验替代自然环境试验提供基础依据。 相似文献
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Sperm number is often a good predictor of success in sperm competition; however, it has become increasingly clear that, for
some species, variation in probability of paternity cannot be explained by sperm number alone. Intraspecific variation in
ejaculate characteristics, such as the number of viable sperm and sperm longevity, may play an equally important role in determining
fertilization success. Here, we assess variation among ejaculates in three factors that may contribute to fertilization success
(number of sperm per ejaculate, viability, and longevity), in a population of Peron’s tree frog (Litoria peronii). We detected large variation among males in the number of sperm per ejaculate and the proportion of viable sperm within
ejaculates, which could not be explained by variation in either male size or body condition. However, the proportion of viable
sperm released by males increased over the season. Finally, we assessed sperm longevity (proportion viable sperm determined
using a dual-fluorochrome vital dye) at two different temperatures. At 23°C, on average, 75% of sperm remained viable after
2 h, but there were significant differences amongst males with the percentage of viable sperm ranging from 43% to 95%. For
sperm incubated at 4°C, ejaculates varied fivefold in sperm longevity with some males having 50% viable sperm after 5 days.
Our data suggest that ejaculate characteristics (sperm number, viability, and longevity) vary widely in Peron’s tree frog
and may therefore play an important role in determining siring success both in the presence and absence of sperm competition.
We discuss the results in relation to selection on ejaculate traits via natural and sexual selection in this and other amphibians. 相似文献