铜胁迫对铜绿微囊藻生长及产毒素的影响

以硝酸盐和磷酸氢盐为主要氮源和磷源,通过测定一定初始氮、磷条件下不同Cu~(2+)浓度培养液中藻密度及藻毒素浓度来研究微量元素Cu对铜绿微囊藻生长的影响.结果表明:当Cu~(2+)浓度为1和10μg·L~(-1)时,藻细胞的生长情况最好,藻密度取得所有浓度梯度中最大值;当Cu~(2+)浓度为1μg·L~(-1)时,藻细胞产毒素总量最大;Cu~(2+)严重缺乏(0.01μg·L~(-1))和过量(100μg·L~(-1))时,藻毒素的合成均受到严重抑制.Cu~(2+)浓度变化影响铜绿微囊藻对硝氮的利用效率,当Cu~(2+)浓度为0.01、0.1及100μg·L~(-1)时,氮元素的利用效率都相对较低.细胞比增长率与单细胞产毒量之间的相关性分析及线性拟合结果表明,单细胞产毒素量与细胞比增长率之间存在很好的线性关系:在Cu~(2+)浓度处于0.01~10μg·L~(-1)范围内,二者表现为正相关;Cu过量时(100μg·L~(-1)),表现为负相关,依据此结果可通过比增长率来预测单细胞的产毒素水平.     

开闭路条件下沉积物微生物燃料电池阳极细菌群落差异解析

采用Solixa高通量测序技术对比了沉积物微生物燃料电池(sediment microbial fuel cells,SMFCs)开闭路条件下启动阳极生物膜细菌群落结构差异.SMFCs开路条件下启动阳极生物膜获得优化序列3 936条,经过97%相似度归并后得到1 581个操作分类单元(operational taxonomic units,OTUs);SMFCs连接5 kΩ电阻闭路启动阳极生物膜获得优化序列3 930条,聚类归并后产生1 551个OTUs,α多样性指数分析表明开路条件下启动阳极生物膜菌群多样性相对更丰富.SMFCs开、闭路条件下启动阳极生物膜优势菌均为Proteobacteria、Firmicutes和Bacteroidetes,它们在开路下阳极生物膜中的含量分别为59.79%、12.54%和9.02%,而在闭路条件下分别为63.02%、10.01%和3.60%,SMFCs闭路条件下运行,地杆菌Geobacter在阳极生物膜中含量高达16.55%.SMFCs开、闭路条件下启动阳极生物膜细菌群落结构的差异说明SMFCs启动过程电子的传递影响电极生物膜微生物群落结构.     

CuO强化MFC活化过硫酸盐降解偶氮染料废水及同步产电研究

利用CuO强化微生物燃料电池(MFC)活化过硫酸盐(PDS),提高MFC对偶氮染料的降解率及同步产电性能.考察初始pH、CuO浓度、PDS浓度等因素对降解率及同步产电的影响.实验结果表明,最佳反应条件:初始pH为3.0,CuO浓度为0.6 mmol·L~(-1),PDS浓度为2 mmol·L~(-1)时,反应4 h后MO降解率达到99.3%.比未投加CuO时MO降解率提高12.8%;MFC最大输出功率密度从53.0 mW·m~(-2)增大到103.5 mW·m~(-2),输出功率密度提高1.95倍;对应的表观内阻从484.1Ω减小到318.6Ω,下降幅度达到34.1%.降解机理研究表明,MO降解过程中的主要活性物质为SO~-_4·和少量·OH.反应前后水样的紫外-可见光谱对比显示,MO降解过程中偶氮键率先断裂,然后生成含苯环类的中间产物,最终得到矿化.     

Prenatal diagnosis of triple X using fetal cells obtained by endocervical lavage

Prenatal diagnosis of aneuploidies currently relies on invasive procedures such as chorionic villous sampling and amniocentesis. These methods can provide an accurate diagnosis of the fetal karyotype but are relatively invasive. Here, we report a case of the prenatal detection of triple X using fetal cells obtained by lavage of the endocervical canal prior to amniocentesis, following ultrasound diagnosis of hydrops fetalis. Copyright © 2003 John Wiley & Sons, Ltd.     

Fetal and maternal progenitor cells in co-culture respond equally to erythropoietin

To explore potentially selective growth conditions for fetal cells in cultures from the blood of pregnant women, we investigated if fetal and adult erythroid progenitors with different hemoglobin expression programs are differentially responsive to erythropoietin (EPO). Co-cultures of clonogenic cells from 12-week fetal and adult peripheral blood were established, and the development of erythropoietic cells was monitored using flow cytometric profiles of correlated cellular contents of fetal and adult hemoglobin (HbF and HbA, respectively). Adult nucleated red cells were classified as F+A−, F+A+ or F−A+. All fetal cells were F+A−. The population of F+A− cells was flow-sorted and fetal cells were identified by fluorescence in situ hybridization (FISH) using chromosome-specific probes. Delayed EPO addition revealed that all types of erythroid cells entered the EPO-dependent phase with similar kinetics, beginning at about Day 4. The data suggest that fetal and adult erythroid stem/progenitor cells have the same initial maturation kinetics in culture independent of their hemoglobin chain expression program. Fetal and adult cells with different hemoglobin profiles also showed similar EPO dose–response curves, determined for different intervals during the first 2 weeks of culture. Thus, the kinetics of entry into the phase of EPO dependence, as well as the sensitivity to EPO at various stages of development, are essentially the same for erythropoietic progenitor cells derived from adult and early fetal blood, which rules out the possibility of using the timing or concentration of EPO for the selective growth of fetal cells from the blood of pregnant women. Copyright © 2001 John Wiley & Sons, Ltd.     

An umbilical cord teratoma in a 17-week-old fetus

A therapeutic abortion was conducted on a 17-week-old male fetus with a large umbilical cord teratoma associated with an exomphalos. A review of the literature revealed ten other cases of umbilical cord teratoma and shows that these tumors have a very polymorphic presentation. Four fetuses and infants died from various causes indicating that there is a need for close follow-up of pregnancies with umbilical cord teratoma. Copyright © 2001 John Wiley & Sons, Ltd.     

Estrogenic activities of two synthetic pyrethroids and their metabolites

Synthetic pyrethroids(SPs) are among the most common pesticides in current use,and so far,several SPs have been assessed for their potential estrogenicities by various methods.Previous studies have shown that the estrogenicities partly come from their metabolites.Although considerable information is available with respect to the metabolism and environmental degradation of SPs,little is known about the estrogenicities of the metabolites.In this study,permethrin(PM) and β-cypermethrin(CP),as well as their metabolites(3-phenoxybenzoic alcohol(PBCOH),3-phenoxybenzaldehyde(PBCHO) and 3-phenoxybenzoic acid(PBCOOH) were evaluated for their estrogenic activities in the MCF-7 human breast carcinoma cell line.In the MCF-7 cell proliferation assay,PM and CP exhibited significant estrogenic activities at 10-7 mol/L,comparable to 17β-estradiol(E2 ) of 10-9 mol/L,with the relative proliferative effect ratios of 55.4% and 56.3%,respectively.The real-time quantitative polymerase chain reaction(qRT-PCR) results confirmed the estrogenicities of PM and CP with significant alteration of pS2 and ERα mRNA levels observed at 10-6 mol/L.For the three major metabolites,PBCOH and PBCOOH exhibited estrogenic activities in all assays,while no significant estrogenic responses was observed for PBCHO compared to the vehicle control.In particular,PBCOH had even slightly stronger estrogenic activity than its parent compounds,indicating that metabolism may be one of the reasons for the estrogenicities of the SPs.Given the widespread use of SPs,the toxicological effects of parent compounds and their metabolites should be taken into consideration in the risk assessment of SPs.     

射频连续电磁波对某数字电路的辐照效应研究

在GTEM室中用射频连续波对某导弹装备上的一块数字控制电路进行电磁辐照,在一定的场强下,引入的电磁干扰还未导致被监测的与非门产生错误反转时,产生控制信号的自激多谐振荡器却首先受到了电磁干扰,主要表现为产生的方波控制信号的占空比增大.分别研究了波源频率在245MHz和330MHz的情况下电路受干扰的情况,辐照实验分别对待测设备按水平横向放置、水平纵向放置和竖直放置3种放置方位分别进行了辐照.最后对水平横向放置的两个频点,将方波控制信号的占空比随场强的变化进行了相关性拟合,建立了数学模型.     

Factors affecting the sex ratio in the honeybee mite <Emphasis Type="Italic">Varroa jacobsoni</Emphasis>

Study of the seasonal variation of the sex ratio in the honeybee mite Varroa jacobsoni demonstrated that sex determination was affected by temperature, order of reproductive cycles, and population densities in the host’s brood cell and the honeybee nest. The mechanism of reproduction ensuring adaptation of the mite to parasitism and reproduction on honeybees are discussed.     

NiO纳米颗粒对小球藻(Chlorella sp.)细胞胁迫性的研究

从小球藻生长及细胞微观结构方面对比研究了纳米NiO与Ni2+对小球藻(Chlorella sp.)的胁迫性.结果表明概率单位法计算得纳米NiO对小球藻96 h EC50为31.4 mg/L,而Ni2+对小球藻96h EC50为1.73 mg/L,利用扫描电子显微镜、透射电子显微镜研究了受纳米NiO和Ni2+胁迫前后小球藻细胞微观结构变化,结果表明,受Ni2+胁迫的小球藻多数出现细胞缩小、变形、细胞器损坏、空泡等细胞凋亡现象,而受纳米NiO胁迫的细胞则部分表现细胞凋亡现象,表明Ni2+对小球藻的毒性远大于纳米NiO.