用~(32)P后标记方法测定职业接触苯乙烯工人静脉血中DNA-环氧苯乙烯加合物

用~(32)P后标记方法,对一组22例接触苯乙烯的工人和8例未接触苯乙烯(空白)的工人进行测试,其静脉血中的淋巴细胞有4例(高浓度,大于40ppm)发现DNA-环氧苯乙烯加合物;而另外接触高浓度苯乙烯、低浓度苯乙烯和空白试样中,均未发现。在已测出的4例中,加合物形成水平为0.07—3.38加合物/10~7正常核酸,DNA的总损伤水平为5—9加合物/10~7正常核酸。 用小牛胸腺DNA、四种脱氧核苷3′-单磷酸分别与环氧苯乙烯进行体外反应,然后用~(32)P后标记法测定产物中的DNA加合物,初步确证有六种加合物及其衍生物存在,修饰位置是鸟苷碱基。并确证了其中三种加合物的化学结构,另外几种加合物的结构有待进一步鉴定。 ~(32)P后标记法测DNA加合物,灵敏度高达1加合物/10~(10)正常核酸,近于人体二倍体细胞基因水平(1.2×10~(10)碱基)。     

^32P后标记方法测DNA加合物

用~(32)P后标记的方法测DNA和环氧苯乙烯体外反应的加合物,是将小牛胸腺DNA和环氧苯乙烯仿照体内条件进行体外反应,反应产物在核酸内切酶及外切酶的存在下,水解成2’-脱氧核糖核苷3’-单磷酸(dNmP).这种水解后的3’-单磷酸在T_4多核激酶的存在下,使γ~(32)P ATP上的放射磷与核苷的磷进行交换反应,生成2’-脱氧核苷-3’,5’-二磷酸(dNDP).被标记的3’,5’-二磷酸及加合物,通过ODS薄层色谱板及PEI纤维阴离子交换色谱板进行适当的分离分辨分析,使DNA加合物从正常的核酸分子中分离出来.用自显影加上空白对照确定加合物的指纹图,最后用液体闪烁计数要定量分析DNA加合物的量。 用这种方法测DNA和环氧苯乙烯体外反应加合物,在自显影指纹图上发现5种多余的斑点,初步确定是DNA的5种加合物或加合物的衍生物.它们的修饰点是鸟嘌呤上的N-7,N-2,O~6位,修饰量在本实验的条件下是1加合物/10~4—6正常核酸.同时用这种方法测动物活细胞和环氧苯乙烯修饰反应产物,发现有DNA加合物存在.在职业接触苯乙烯工人静脉血中也发现有DNA-环氧苯乙烯的加合物,测定结果其样品指纹图与体外反应DNA指纹图类似. ~(32)P后标记方法是灵敏的,最高可侧到1加合物/10~(10)—11正常核酸,这已接近二倍体细胞的基因水平,是当今测DNA加合物方法中最     

^32P后标记法测DNA加合物

＾３２Ｐ后标记方法测ＤＮＡ－致癌物的加合物过程是用小球菌核酸酶和脾核酸酶将ＤＮＡ及加合物酶解成２′－脱氧核苷３′－单磷酸（３′－ｄＮｍＰ＋３′－ｄｘｍＰ）,以它为底物,用Ｔ４多核苷酸激酶催化,使γ＾３２ＰＡＴＰ的放射＾３２Ｐ转移反应到底物上,形成２′－脱氧核苷３′５′．ｄＮＤＰ＋３′５′＊ｄｘＤＰ）,用ＯＤＳ－ＴＬＣ和ＰＥＩ－ＴＬＣ结合将标记过的二磷酸分离分辨,用自显影制成加合物的指纹图,液闪计数     

用^32P后标记方法测定典型有毒污染物的DNA加合物

＾３２Ｐ后标记方法测定生物样品里的有毒污染物－ＤＮＡ加合物的过程是用小球菌核酸酶和脾核酸酶将ＤＮＡ及加合物酶解成为２‘－脱氧核苷３’－单磷酸，以它为底物，在Ｔ４多核到激酶的催化下，与γ＾３２ＰＡＴＰ进行文笔磷的转移反应，形成带放射磷的２‘－脱氧核苷３’，５‘－二磷酸酯ＯＤＳ－ＴＬＣ吸附薄层板和ＰＥＩ－ＴＬＣ阴离子交换薄层板将标记过的带放射磷的＾＊３’，５‘－二磷酸酯分离分辨，然后用自显影技术制成加     

灭幼脲光解产物DNA加合物的研究

灭幼脲（邻氯苯甲酰基－对氯苯基－脲）本身是一种低毒，低残留，没有致突、致癌性的农药，但是它的某些分解产物，如：氯苯、对氯苯、对氯苯基脲等有一定的毒性，邻氯苯甲酰胺（灭幼脲的主要光解产物－ＣＢＡ）和未经分离的灭幼脲光解产物的混合物，在试管反应条件下能与小牛胸腺ＤＮＡ反应形成多种ＤＮＡＡ加合物，用Ｐ１加强灵敏度的＾３２Ｐ后标记方法分析，有四种ＤＮＡ加合物被检出（ＤＮＡ－ＣＢＡ），实验证明，邻氯苯甲酰妥     

微波消解—电感耦合等离子体质谱法测定植物中痕量稀土元素

研究了电感耦合等离子体质谱（ＩＣＰ－ＭＳ）测定植物中痕量稀土元素（ＲＥＥｓ）的方法。详细讨论了测定稀土元素的质谱干扰及基体的抑制效应,采用代数法可有效地校正质谱干扰,内标法可以补偿基体的抑制效应。根据植物标准参考物质（ＧＳＶ－２,ＧＳＶ－４）的分析结果评价方法的准确性。在微波条件下,ＨＦ／ＨＣｌＯ４／ＨＮＯ３混合体系能快速而有效地分解植物样品,直接稀释后用ＩＣＰ－ＭＳ测定其中的稀土元素。     

生物检测标志物和分析方法

有四种分子水平的生物检测标志物在当前研究环境因素－基因变异－疾病之间相关性的分子生物学领域中起着重要的作用，它们是生物大分子样品的ＤＮＡ加合物，蛋白质加合物、８－羟基脱氧鸟苷、生物排泄筘的烷基化脱氧嘌呤，因为ＤＮＡ的特殊作用，ＤＮＡ加合物作为生物标志物倍受重视，ＤＮＡ加合物的分析方法有荧光法（灵敏度达１加合物／１０＾５－６正常核酸），免疫法（灵敏度达１加合物／１０＾６－８正常核酸），＾３２Ｐ后标记     

β-环糊精及羧甲基-β-环糊精对取代吲哚化合物的增溶

本文用羧甲基－β－环糊精及β－环糊精对两种取代吲哚化合物２－（４’－甲氧基苯）－吲哚与２－（３‘,４’－二甲基苯）－吲哚进行了增溶实验,结果表明：羧甲基－β－环糊精与二者均形成稳定的１：１的包合物,而β－环糊精与二者形成１：２的包合物。     

红壤对SO_4~（2－）和H_2PO_4~－的吸附与竞争吸附研究

研究红壤对ＳＯ４（２－）和Ｈ_２ＰＯ(４－)的吸附与竞争吸附机理．实验结果表明，红壤吸附Ｈ２ＰＯ４－的量远远大于ＳＯ４（２－），前者几乎是后者的２倍．在两种阴离子共存体系中，Ｈ２ＰＯ４－使ＳＯ４（２－）吸附量明显减少，在浓度低时甚至出现负吸附；ＳＯ４（２－）对Ｈ２ＰＯ４－吸附量的影响很小．说明土壤对Ｈ２ＰＯ４－的吸持力较强，为高强度专性吸附，不易于被其它阴离子解吸；土壤对ＳＯ４（２－）的吸持力则较弱，为低强度专性吸附或非专性物理吸附，能够被吸持力更强的阴离子完全解吸．     

交联壳聚糖冠醚的合成及其对金属离子的吸附性能

本文合成了交联壳聚糖苯并－１５－冠－５醚和交联壳聚糖苯并－１８－冠－６醚,研究了它们对Ａｇ（Ⅰ）Ｐｄ（Ⅱ）,Ｐｂ（Ⅱ）,Ｃｄ（Ⅱ）,Ｃｒ（Ⅲ）等金属离子的吸附性能和选择性,实验结果表明：无论是在单一金属离子体系还是在二元或三元金属离子体系中,ＣＣＴＳ－ＢＸ和ＣＣＴＳ－ＢＹ对Ａｇ（Ⅰ）和Ｐｄ（Ⅱ）者有较高的吸附选择性。     

改性污泥活性炭对苯乙烯的吸附

以城市污泥为原料制备活性炭,对其进行改性,研究了改性前后的比表面积、表面酸碱基团、对苯乙烯的静态吸附容量、吸附穿透曲线、脱附活化能等吸附性能.结果表明,硫酸铜溶液浸渍改性后可使污泥活性炭比表面积明显提高,其中0.1 mol.L-1硫酸铜溶液浸渍改性的污泥活性炭较改性前的比表面积提高了32%(达704.7 m.2g-1).硫酸铝溶液和硫酸铜溶液浸渍改性可以使污泥活性炭表面酸性基团含量提高、表面碱性基团含量减少;对苯乙烯的静态吸附容量提高到改性前的两倍以上(分别达211.4 mg.g-1和178.8 mg.g-1)、对苯乙烯的动态吸附穿透时间由2 min提高到10 min以上、脱附活化能由2.94 kJ.mol-1提高到6 kJ.mol-1以上.改性后活性污泥炭的吸附性能得到明显提高.     

苯乙烯致DNA间接损伤效应的光电化学生物传感器快速检测

许多有机化合物自身没有致癌毒性,但进入生物体内,经过体内代谢酶的催化后转化成活性中间体,与DNA形成共价化合物.这些间接的损伤会最终导致DNA分子结构和功能的变化,对人类的健康造成威胁.因此,建立一种快速有效的方法检测间接致癌化合物对DNA的损伤,成为当前研究的热点.论文建立了一种新型的光电化学生物传感器来检测有机化合物苯乙烯对DNA的间接损伤效应,该传感器以层层自组装的方式将光电信号分子、双链DNA和血红蛋白组装在半导体电极上.在H2O2存在的条件下,传感膜中的血红蛋白可将苯乙烯转化为氧化苯乙烯,氧化苯乙烯扩散到膜内,与DNA形成加合物,引起DNA结构变化,导致光电分子光电流信号的增加.实验中,将修饰好的电极置于终浓度为2mM H2O2和2%苯乙烯(体积比)的混合液(pH7.3的磷酸缓冲液配制)中反应一段时间后,在电解质溶液中进行光电流检测.实验结果表明,光电流信号随着反应时间逐渐升高,在30min后趋于稳定,表明苯乙烯在传感膜上的氧化和DNA的损伤反应基本完成.与反应前相比,反应后光电流增加了40%,并且酶催化苯乙烯生成的氧化苯乙烯经紫外可见光谱得到验证.论文建立的光电化学生物传感器模拟了体内DNA损伤反应过程,能快速有效地检测苯乙烯对DNA的间接损伤效应,有望为有机化合物潜在基因毒性的风险评估提供一个快速筛查工具。     

聚丙烯酸钠薄膜/K^＋交换玻璃光波导元件的研制及其对苯乙烯蒸气的气敏性研究

采用低分子量聚丙烯酸钠作为敏感试剂,通过旋转涂胶法固定在钾离子交换玻璃光波导表面做成纳米级的薄膜,研制了低分子量聚丙烯酸钠薄膜/K＋离子交换玻璃光波导气敏元件.将该气敏元件固定在光波导气体检测系统中,对挥发性有机物蒸气进行检测.结果表明,室温下该气敏元件对苯乙烯蒸气具有较高的选择性响应,响应和恢复速度快（分别为6 s和...     

聚丙烯、聚乙烯苯和丁苯橡胶粗粒化法处理模拟含油废水

采用聚丙烯、聚乙烯苯和丁苯橡胶粗粒化法对模拟含油废水进行处理,研究发现,用聚丙烯作为填充材料时,除油效果最好,最高可达86.3%;聚乙烯苯除油效果比前者略低,但在处理低浓度含油废水时,除油率可达到95%以上;相比前两种,丁苯橡胶的处理效率较低.     

Importance of greater interdisciplinarity and geographic scope when tackling the driving forces behind biological invasions

Invasive non-native species are important drivers of ecosystem change, yet the driving forces of biological invasions themselves are poorly understood. Such information is essential to ensure policies focus on the most relevant drivers, and that future scenarios capture the full range of potential outcomes for invasive non-native species. I carried out a bibliometric analysis of articles published from 2000 to 2020 that address either invasive non-native species or biodiversity and ecosystem services and that also mention 1 or more drivers of ecosystem change. I examined 5 indirect drivers (demographic, economic, governance, sociocultural, and technological) and 6 direct drivers (climate change, invasive non-native species, land-use or sea-use change, natural hazards, pollution, and resource extraction). Using the Web of Science core collection of citation indexes, I undertook searches of article titles and keywords and retrieved 27,462 articles addressing invasive non-native species and 110,087 articles dealing with biodiversity or ecosystem services. Most research to date on biological invasions as well as on biodiversity and ecosystem services has focused on anthropogenic direct drivers of ecosystem change rather than indirect drivers. Yet currently, less than 18% of articles addressing biological invasions examined drivers of ecosystem change, a similar level to that found over 20 years ago for biodiversity or ecosystem services. Knowledge of the drivers of biological invasions is limited, emphasizes tractable drivers over those that require an interdisciplinary approach, and is biased toward developed economies. Drivers generally deemed important for biological invasions, such as governance and resource extraction, accounted for less than 2% of research effort. The absence of a systematic understanding of the forces that drive invasive non-native species and how they interact means that attempts to mitigate or forecast biological invasions are likely to fail. To address biological invasions requires a much better orientation of national and international research on drivers in relation to both their actual importance as well as their policy relevance.     

Mitigating the effects of climate change on the nests of sea turtles with artificial irrigation

For sea turtles, like many oviparous species, increasing temperatures during development threaten to increase embryonic mortality, alter offspring quality, and potentially create suboptimal primary sex ratios. Various methods are being implemented to mitigate the effects of climate change on reproductive success, but these methods, such as breeding programs, translocations, and shading, are often invasive and expensive. Irrigation is an alternative strategy for cooling nests that, depending on location, can be implemented relatively quickly and cheaply. However, multiple factors, including ambient conditions, nest substrate, and species characteristics, can influence irrigation success. Additionally, irrigation can vary in duration, frequency, and the volume of water applied to nests, which influences the cooling achieved and embryonic survival. Thus, it is critical to understand how to maximize cooling and manage risks before implementing irrigation as a nest-cooling strategy. We reviewed the literature on nest irrigation to examine whether artificial irrigation is feasible as a population management tool. Key factors that affected cooling were the volume of water applied and the frequency of applications. Embryonic responses varied with species, ambient conditions, and the timing of irrigation during development. Nest inundation was the key risk to a successful irrigation regime. Future irrigation regimes must identify clear targets, either primary or adult sex ratios, that maximize population viability. Monitoring population responses and adjusting the irrigation regime in response to population characteristics will be critical. Most studies reported on the manipulation of only one or two variables, further research is required to understand how altering multiple factors in an irrigation regime influences the cooling achieved and embryonic responses.     

Positive and Negative Effects of a Threatened Parrotfish on Reef Ecosystems

Species that are strong interactors play disproportionately important roles in the dynamics of natural ecosystems. It has been proposed that their presence is necessary for positively shaping the structure and functioning of ecosystems. We evaluated this hypothesis using the case of the world's largest parrotfish (Bolbometopon muricatum), a globally imperiled species. We used direct observation, animal tracking, and computer simulations to examine the diverse routes through which B. muricatum affects the diversity, dispersal, relative abundance, and survival of the corals that comprise the foundation of reef ecosystems. Our results suggest that this species can influence reef building corals in both positive and negative ways. Field observation and simulation outputs indicated that B. muricatum reduced the abundance of macroalgae that can outcompete corals, but they also feed directly on corals, decreasing coral abundance, diversity, and colony size. B. muricatum appeared to facilitate coral advancement by mechanically dispersing coral fragments and opening up bare space for coral settlement, but they also damaged adult corals and remobilized a large volume of potentially stressful carbonate sediment. The impacts this species has on reefs appears to be regulated in part by its abundance—the effects of B. muricatum were more intense in simulation scenarios populated with high densities of these fish. Observations conducted in regions with high and low predator (e.g., sharks) abundance generated results that are consistent with the hypothesis that these predators of B. muricatum may play a role in governing their abundance; thus, predation may modulate the intensity of the effects they have on reef dynamics. Overall our results illustrate that functionally unique and threatened species may not have universally positive impacts on ecosystems and that it may be necessary for environmental managers to consider the diverse effects of such species and the forces that mediate the strength of their influence. Efectos Positivos y Negativos de un Pez Loro Amenazado Sobre Ecosistemas Arrecifales     

Form-specific fragances fromOphrys insectifera L. (Orchidaceae) attract species of different pollinator genera. Evidence of sympatric speciation?

Two closely related forms ofOphrys insectifera were observed in the field to attract different pollinator species selectively.O. i. ssp.insectifera attracted males of two species ofArgogorytes (Sphecidae, Hymenoptera Aculeata) andO. i. ssp.aymoninii attractedAndrena combinata males (Andrenidae, Apoidea, Hymenoptera Aculeata). A third form,O. aff.i. ssp.insectifera, attracted none of these three species. Volatile compounds from flowers and inflorescences of the three forms (originating from Öland, Sweden, and Aveyron, France) were collected, using entrainment, enfleurage, and solvent extraction techniques, and identified by gas chromatography — mass spectrometry. Scent differences between the three forms were confirmed in the amounts of aliphatic hydrocarbons (C₁₁–C₁₉), methyl esters (C₁₄–C₁₈), short chain aliphatic 1-alcohols (C₆–C₁₂), and monoterpene alcohols (C₁₀).     

Estimation of the surface stress from the streamwise pressure gradient: The Kármán Integral Momentum Equation revisited

A method is developed to estimate the stress at the surface in a portable wind tunnel for wind erosion studies. The boundary layer height and the pressure gradient are used in a simple expression from the Kármán Integral Momentum Equation. Values of friction velocity u _* are within 10% of experimental values obtained through correlation techniques, including measurements of differential pressures with the Murdoch Turbulence Probe MTP and the X-wire, hot-wire anemometer XWA. Wind velocity and stress profiles reveal logarithmic trends and a constant stress layer near the surface in the DAWA portable wind tunnel. Realignment of the statistics with the mean wind is essential.