彗星试验的改良及其在工业废水监测中的应用

为了探讨彗星试验在工业废水监测中的应用,本文将常规的细胞暴露方式改良为浸泡染毒,既提高了实验的敏感性,又使得该试验直接用于监测工业废水的遗传毒性成为可能．作者用改良彗星试验直接检测了几种工业废水所引起的V79细胞DNA损伤．结果表明,所测的各种工业废水均含有DNA损伤剂,能够诱发培养的V79细胞DNA链断裂,其中以制革厂废水的DNA损伤作用最强．本研究显示出改良彗星试验在综合评价各种废水遗传毒性方面的广阔应用前景．     

三峡库区大宁河藻细胞昼夜垂直迁移研究

旨在准确为三峡库区藻华预警提供基础数据,本研究于2011年7月底在三峡库区大宁河流域进行藻细胞昼夜垂直迁移试验.结果表明,大宁河在此期间,藻细胞主要以绿藻、蓝藻、硅藻和甲藻为主;藻细胞在水体中的分布不均匀,72.5%～76.2%的藻细胞集中在0.5～4.0 m水体之间,0～0.5 m处藻细胞较少,占垂直水体藻密度的7.5%～16.3%,白天藻细胞Morisita指数(MI)为1.41～1.97,夜晚MI指数为1.17～1.55,叶绿素a白天MI指数为1.31～1.59,而夜晚MI指数为1.17～1.39.藻细胞在水体中存在明显的昼夜垂直迁移现象,该现象主要发生在0.5～4.0 m水体之间.水体中的藻密度受营养盐的影响较小,与可溶解性总磷显著相关(r=0.89),藻密度主要受温度、pH值和导电率影响,藻密度与温度、pH值和导电率呈极显著相关,相关系数分别为0.96、0.97和-0.99.     

外阻对三室MFC产电性能和Cu迁移特性的影响

构建一种新型的三室微生物燃料电池（microbial fuel cells,MFCs）对重金属Cu污染的土壤进行修复,研究不同外阻条件下MFC的产电性能和土壤中Cu的迁移去除情况.结果表明,当外接电阻从100Ω增大到1000Ω时,三室MFC的输出电压从0.1V提高到0.4V,最大功率密度从1.10W/m³降低到0.71W/m³,且阴极极化现象也随外阻增大而更加显著.装置运行63d后,MFC外接电阻越大,近阳极土壤区的Cu的去除率越高,外阻为1000Ω的MFC近阳极土壤区的Cu去除率达到39.7%.通过改进欧共体标准（BCR）连续提取法分析重金属的形态,发现乙酸可提取态和可还原态为Cu迁移的两种主要形态.此外,土壤的性质也发生变化,pH值呈现由阳极到阴极逐渐升高的趋势,而电导率则相反.阴极电极的扫描电镜（SEM）和X射线衍射（XRD）结果也表明部分迁移到阴极的Cu（Ⅱ）被还原成单质Cu.     

游离亚硝酸预处理对剩余污泥电解及微生物群落结构的影响

为打破传统厌氧发酵周期长,有机质利用率低等瓶颈,增强污泥的资源利用和能源回收,探讨了游离亚硝酸（FNA）预处理对剩余污泥电解效果及微生物群落的影响.对比分析了FNA预处理前后剩余污泥在微生物电解池（MEC）中的电流和氢气产生、溶解性有机物和挥发酸的释放和利用及功能菌群的变化情况.结果表明,FNA预处理能有效地促进剩余污泥在MEC系统中的水解和酸化,其溶解性糖类、蛋白和挥发酸的含量远高于未预处理组,进而促进了水解发酵菌、产电菌及反硝化菌的生长和富集,最终挥发酸利用率均在97%以上,表现为电流（1.9mA）和氢气（0.86mL/g VSS）的增强,分别是空白组的3.8倍和5.1倍.     

单室空气阴极微生物燃料电池硝酸根去除系统的建立和性能研究

本文以单室空气阴极微生物燃料电池(Microbial Fuel Cell,MFC)处理含不同浓度硝酸根的模拟废水,研究了NO~-_3-N初始浓度和开闭路培养方式对单室MFC的启动、硝酸根去除性能和产电性能的影响.结果表明,随着NO~-_3-N初始浓度的提高,MFC的NO~-_3-N平均去除速率达到稳定值所需时间增加,NO~-_3-N平均去除速率提高.当NO~-_3-N初始浓度为200 mg·L~(-1)时,闭路组MFC的NO~-_3-N平均去除速率达到(3.52±0.28) kg·m~(-3)·d~(-1),高于相近条件下许多传统生物反应器的NO~-_3-N平均去除速率.硝酸根去除过程主要发生在MFC运行周期的前期.硝酸根对阳极生物膜中主要产电菌Geobacter的生物量没有影响.当基质充足时,所有闭路组MFC的最大功率密度相近(～27 W·m~(-3)).闭路组MFC比开路组MFC具有更高的NO~-_3-N去除速率,可能与其阳极生物膜具有电化学还原亚硝酸根能力和Thauera易在其阳极上富集有关.     

植物微生物燃料电池修复Cr(Ⅵ)污染湿地土壤及机理研究

本研究通过引入沼生植物香蒲构建植物微生物燃料电池系统(P-MFC)修复Cr(VI)污染湿地土壤,考察了植物、不同初始Cr(VI)浓度对系统产电及去除效率的影响.结果显示,香蒲种植能显著提高P-MFC运行性能,系统最大功率密度与Cr(VI)去除率分别提高至23.83 mW·m~(-2)、33.01%,随着Cr(VI)暴露浓度的升高,系统运行性能降低.利用P-MFC修复Cr(VI)污染土壤过程中,电化学还原作用是Cr(VI)去除的主要机制,近90%的Cr(VI)通过电化学还原去除,系统中0.3%～1.86%的Cr(VI)被香蒲吸收富集,3.5%～9.5%的Cr(VI)被微生物与还原性有机物直接还原.通过高通量测序技术分析发现,香蒲种植与低浓度Cr(VI)暴露下阳极微生物群落多样性较大,优势门类Proteobacteria相对丰度最高为63.9%,较未种植香蒲与高浓度Cr(VI)暴露条件下提高了3.4%～19.0%,电化学活性微生物Geobacter相对丰度最高为12.4%,较未种植香蒲与高浓度Cr(VI)暴露条件下提高了4.4%～6.8%.系统中对Cr(VI)具有较强耐受性与还原能力的Acinetobacter、Bacillus占有较大比例,且相对丰度随暴露浓度升高而增大,最高分别为19.0%、14.4%,进一步说明微生物群落在Cr(VI)去除上发挥了一定作用.上述结果表明,P-MFC在去除湿地土壤Cr(VI)污染方面具有良好的潜力.     

Prenatal diagnosis of a fetus harboring an intermediate load of the A3243G mtDNA mutation in a maternal carrier diagnosed with MELAS syndrome

We prenatally diagnosed MELAS syndrome in a fetus whose mother and older brother had the MELAS-specific A3243G mutation. The mutant mtDNA level of the amniotic fluid cells was not significantly different from that of the postnatal peripheral blood and hair follicle samples. The obstetrical course was uncomplicated except for transient exacerbation of the mother's diabetes, which required insulin control. At term, the infant was macrosomic, and the delivery was complicated by shoulder dystocia. MELAS syndrome in itself does not influence either the prenatal course of the mother or the fetal outcome. In contrast to the fulminating clinical course of this mother's first child, MELAS symptoms did not develop in her second child until age four, despite similar high tissue levels of mutant mtDNA. The phenotypic diversity in two offspring with similar higher levels of mutant mtDNA suggests that prenatal genetic diagnosis of cultured amniotic cells may yield results that are poor prognosticators of fetal outcome. Copyright © 2004 John Wiley & Sons, Ltd.     

Detection and enumeration of colonic mucosal cells in amniotic fluid using a colon epithelial-specific monoclonal antibody

Since its introduction, prenatal diagnosis of chromosomal and metabolic disorder by mid-trimester amniocentesis has relied upon the use of a mixture of fetal cells obtained from amniotic fluid. Little knowledge has been gained in the sorting of these cells for diagnosis of tissue-specific disorders. In an attempt to determine the contribution of fetal colonic mucosal cells to the overall amniocyte population, we used the colonic epithelial-specific monoclonal antibody (MC-Ab) 7E₁₂H₁₂, IgM isotype. Specimens of the small intestine, colon, buccal mucosa, kidney, urinary bladder, and umbilical cord were obtained from electively aborted normal fetuses of 12–28 weeks' gestation. All of these specimens were examined with 7E₁₂H₁₂ by the immunoperoxidase technique. The MC-Ab reacted with the colonic epithelial cells but not with any of the other tissues. In addition, 40 amniotic fluid samples obtained from women between 16 and 18 weeks of gestation, who underwent amniocentesis because of advanced maternal age, were tested using a fluorescent activated cell sorter. Among the amniotic fluid specimens examined, 18·4 ± 10·3 percent cells reacted with 7E₁₂H₁₂. Double immunofluorescence studies revealed that all Mc-Ab-stained cells contained secretory component, confirming that they were epithelial in origin. All fetuses whose amniotic fluid was analysed had normal karyotypes and amniotic fluid alpha-fetoprctein levels that were also normal. This study demonstrates that cell-specific Mc-Ab can be used to detect colon cells in the amniotic fluid and that colon cells contribute significant numbers in the mixture of amniotic fluid cells. This technique could be helpful in the prenatal diagnosis of disorders in which the flow of amniotic fluid through the fetal intestine is impaired, such as cystic fibrosis, imperforate anus, Hirschsprung aganglionic megacolon, and intestinal atresia.