秀丽线虫转基因品系在环境暴露评价与毒理学研究中的应用

目前,模式动物秀丽线虫已被广泛应用于环境暴露评价和环境毒理学研究中.在系统介绍了各种秀丽线虫转基因品系在环境暴露与毒性评价以及环境毒理研究中的应用进展基础上,分析了秀丽线虫转基因品系在环境暴露与毒性评价研究中的灵敏性与直观性的特点.最后,讨论了秀丽线虫转基因品系在环境暴露与毒性评价以及环境毒理研究中尚存在的问题和可能的...     

基于模式生物秀丽隐杆线虫的环境污染物生殖毒性研究进展

由于人类社会的发展,环境污染也越来越严重,研究环境污染物对生态及人类健康的影响极为重要。生殖系统是人和动物繁衍后代的重要系统,常见环境污染物对生殖系统的影响正引起研究人员的广泛关注。秀丽隐杆线虫具有身体透明、品系丰富和遗传背景清楚等优点,为生殖毒理学研究提供了一个便利的平台。以秀丽隐杆线虫为模型已对多种环境污染物的生殖毒性进行了评价。本文重点叙述了重金属、纳米材料、有机物等化学污染,辐射、磁场等物理污染,以及病毒等生物污染对秀丽线虫生殖系统的影响,并归纳讨论了环境污染物造成生殖功能障碍的几种主要机制,如氧化应激、DNA损伤、内质网应激以及神经损伤等,但不同类型污染物的毒性效应与其自身的物化性质紧密相关。环境污染物诱导的生殖毒性中不同响应机制之间的关联性、不同发育阶段的敏感性差异、污染物的传代效应以及有效的缓解方式的筛选等都有待进一步的开展。     

农药对秀丽隐杆线虫毒性效应及其机制的研究进展

随着大量农药被广泛的使用并最终汇聚到环境介质中,对生态环境和人体健康产生潜在影响。秀丽隐杆线虫(Caenorhabditis elegans)是土壤中最丰富的后生动物,在土壤生态系统中具有重要地位,并作为一种重要的模式生物广泛应用于环境毒理学研究。本文从秀丽隐杆线虫常用的毒理学研究方法入手,以致死率、生长发育、运动行为、繁殖、活性氧自由基(ROS)水平、细胞凋亡水平、相关基因表达量和蛋白水平等作为测试指标,归纳总结农药对秀丽隐杆线虫的衰老性、神经及生殖系统的毒性效应,分析探索其毒性机理,并展望了未来的研究重点。     

量子点对秀丽隐杆线虫的毒性效应及其调控机制的研究进展

量子点(quantum dots,QD)作为一种纳米微晶体,由于其出色的光学特性,已经被广泛应用于电子、生物医学成像、生物传感器和药物递送中,因而量子点的生物安全性也变得至关重要.秀丽隐杆线虫作为一种简单的生物模型,生物学基础完善、生命周期短、繁殖量大、生活特征易获得,不仅可以提供全动物水平的生理相关数据,还允许在单细胞水平上进行分析,是量子点毒性试验的良好生物模型.本文总结了量子点对秀丽隐杆线虫毒性研究的进展,重点阐述了量子点导致线虫四大系统的毒性效应及其可能的毒作用机制,同时展望了今后秀丽隐杆线虫在量子点毒性研究甚至纳米毒性研究领域的广阔前景.     

利用模式动物秀丽线虫建立环境毒物毒性的评估研究体系

模式动物秀丽线虫(Caenorhabditis elegans)在环境科学与生态毒理学研究中发挥着越来越重要的作用,目前利用秀丽线虫已初步建立起较为完善的环境毒物毒性评估体系.该评估体系具体由如下一些指标构成:致死率、最长寿命与半数致死天数、细胞凋亡、个体发育、生殖、运动行为、乙酰胆碱酯酶活性、学习行为、记忆行为、转基因品系、突变体、基因表达模式.论文系统总结了近十多年来利用秀丽线虫进行环境毒物毒性评估的研究体系,并对各个指标的研究方法、研究现状、存在的问题及应用中需要注意的地方进行了讨论。     

铁矿区水环境样品对秀丽隐杆线虫的毒性研究

矿区环境问题是近年来各研究领域关注的焦点。为探究矿区水环境潜在的生物安全性问题,以安徽省霍邱县大型铁矿区地表水体为研究对象,以秀丽隐杆线虫作为实验动物模型,并以其生长和生殖发育作为生物检测终点,考察了线虫对该矿区周边5个地表水样品的毒性效应的响应。结果表明,矿区水环境样品对线虫的生长和生殖发育具有明显的损伤效应,且这种损伤效应的大小与水样采集点距离采矿区的远近以及水样中主要污染物的含量密切相关。进一步通过主成分分析发现,总铁、可溶性铁、铜、铬和砷是环境水样造成线虫毒性效应的主要影响因子。上述研究结果为铁矿区水环境生物安全性的监测和评价提供了一种新的技术方法和新的视角,并为铁矿区健康风险规避提供新的思路和理论基础数据。     

GO通过氧化损伤激活秀丽线虫未折叠蛋白反应

以秀丽线虫为受试生物,探讨氧化石墨烯(GO)对秀丽线虫未折叠蛋白应答的激活及其与氧化应激的关系。将L4幼虫暴露于GO中24 h,通过检测活性氧(ROS)水平、乳酸脱氢酶(LDH)、丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)等指标评估GO对秀丽线虫所致氧化损伤;以hsp-4和hsp-6分别作为秀丽线虫内质网和线粒体未折叠蛋白反应(UPR)的报告基因评价GO对秀丽线虫UPR应答的激活;同时以谷胱甘肽(GSH)作为抗氧化剂探讨GO所致UPR应答与氧化应激的关系。研究结果显示,GO暴露后秀丽线虫体内ROS、LDH和MDA水平升高,抗氧化酶活性上升;内质网和线粒体UPR反应增强,GSH预处理可以降低内质网和线粒体UPR应答。研究表明,GO短期暴露可以诱导秀丽线虫机体氧化应激进而激活UPR应答,抗氧化保护可以降低UPR应答反应。     

转录因子ATF-7参与调控氧化石墨烯(GO)对秀丽线虫的致毒效应

ATF-7是具有亮氨酸拉链结构的转录激活因子,为了解其是否参与调控氧化石墨烯(GO)的致毒效应,以秀丽线虫为在体研究模型,通过运动行为、肠道活性氧簇(ROS)水平和寿命分析,评价atf-7 RNA干扰对秀丽线虫应答GO毒效应的影响;同时以qRT-PCR和Patf-7::mCherry转基因秀丽线虫检测GO对atf-7表达水平的影响.结果显示,GO暴露可以降低秀丽线虫头部摆动和身体弯曲频率,且运动行为的下降与GO暴露浓度呈正相关;atf-7干扰秀丽线虫对GO致毒效应更加敏感,0.1 mg/L GO就可导致头部摆动和身体弯曲频率显著下降(P 0.01);在GO暴露条件下,atf-7干扰秀丽线虫的平均寿命由13.54 d缩短到8.8 d,寿命缩短程度大于空载干扰组(P 0.01);atf-7干扰秀丽线虫在GO暴露条件下肠道ROS水平比未暴露情况下上升了3.33倍,而空载组肠道ROS水平上升了2.66倍,atf-7干扰秀丽线虫对GO所致肠道ROS的积累更加明显(P 0.01).GO暴露可以诱导秀丽线虫atf-7的表达水平,GO暴露组atf-7在转录水平和蛋白水平较对照组分别上调了164倍和200倍.因此,atf-7是秀丽线虫应对GO致毒效应中所必需的,秀丽线虫通过上调atf-7的表达以应对GO毒效应,对秀丽线虫进行atf-7干扰降低其表达水平可使秀丽线虫对GO致毒效应更加敏感.(图4表1参24)     

砷与农药草甘膦、敌敌畏对秀丽隐杆线虫的联合毒性

农田常遭受砷和农药污染,这2种污染会产生联合毒性,影响生物体健康。利用野生型秀丽隐杆线虫进行砷、草甘膦和敌敌畏的24h单一毒性和联合毒性实验。结果表明,砷、草甘膦和敌敌畏对秀丽隐杆线虫24h-LC50分别为130.5mg·L-1、18.5mg·L-1、3.3μL·L-1;通过等效毒性相加法实验,发现砷与草甘膦对秀丽隐杆线虫的联合毒性为协同作用,砷与敌敌畏对秀丽隐杆线虫的联合毒性为拮抗作用。     

玉米赤霉烯酮暴露对秀丽线虫生殖系统的损伤作用

环境雌激素玉米赤霉烯酮(ZEN)的生态安全性近年来受到越来越多的关注。以秀丽隐杆线虫(Caenorhabdites elegans)为模式生物研究ZEN对线虫的生殖损伤作用。在DIC显微镜下观察,48 h暴露后与对照组相比,暴露组线虫性腺臂明显萎缩,卵母细胞数目和大小均受到显著影响(P0.01),并且可见部分暴露组线虫产卵器严重畸形。这均表明ZEN暴露对秀丽隐杆线虫生殖系统的发育和功能可产生损害作用。     

基于秀丽隐杆线虫的微量水样环境毒理学研究

目前,环境水样个体水平的毒理学检测成本较高、耗时长,且检测后的水样若处理不当易造成环境的二次污染。通过使用易于培养和观察、个体微小的模式生物—秀丽隐杆线虫作为实验对象,利用毛细玻璃管的虹吸原理将线虫暴露于微量的环境水样进行染毒培养,实现微量水样在个体水平的毒理学评价。为了验证该方法的可行性,检测了暴露组线虫与对照组线虫的生殖腺细胞损伤水平、活性氧自由基(ROS)产生量、氧化应激水平、脱氧核糖核酸(DNA)损伤水平等生物终点的差异性。研究结果有助于为微量环境水样在个体水平的毒理学分析提供一种快速、可行、廉价的评价手段。     

盐酸四环素对秀丽线虫(C.elegans)的急性与多代毒性研究

环境中抗生素的生态安全性受到越来越多的关注.以盐酸四环素(TCH)为对象、秀丽线虫(C.elegans)为模式生物,开展了急性与多代毒性研究.急性毒性实验表明盐酸四环素对秀丽线虫的LC50为167.5mg·L-(112h)、82.9mg·L-(124h),与现有四环素毒性数据相比,秀丽线虫对TCH的毒性更为敏感.分别对虫卵和成虫进行多代毒性的研究表明,盐酸四环素环境水平(μg·L-1)下的暴露,对秀丽线虫母代(P0)、子一代(F1)和子二代(F2)的逆向运动抑制率(RMI)、身体弯曲频率(BBFI)、Omega运动抑制率(OMI)3个行为学指标均具有显著的抑制作用,而且行为学指标比死亡率更加敏感,虫卵比成虫更加敏感.多代毒性作用的结果表明,盐酸四环素对P0、F1和F2产生的毒性存在差异,对于RMI和BBFI,其毒性作用强度为P0>F2>F1;对于OMI,其毒性作用强度为P0>F1≈F2.代际之间没有显示世代毒性逐代恶化或逐代修复的一般规律,可能与行为学指标的敏感性差异、盐酸四环素自身的降解、生物抗性有关.     

Deconstructing adaptive management: criteria for applications to environmental management.

The concept of adaptive management has, for many ecologists, become a foundation of effective environmental management for initiatives characterized by high levels of ecological uncertainty. Yet problems associated with its application are legendary, and many of the initiatives promoted as examples of adaptive management appear to lack essential characteristics of the approach. In this paper we propose explicit criteria for helping managers and decision makers to determine the appropriateness of either passive or active adaptive-management strategies as a response to ecological uncertainty in environmental management. Four categories of criteria--dealing with spatial and temporal scale, dimensions of uncertainty, the evaluation of costs and benefits, and institutional and stakeholder support--are defined and applied using hypothetical yet realistic case-study scenarios that illustrate a range of environmental management problems. We conclude that many of the issues facing adaptive management may have less to do with the approach itself than with the indiscriminate choice of contexts within which it is now applied.     

以壳聚糖微球为载体的固定化乙酰胆碱酯酶的基本性质

为探讨以壳聚糖微球为载体制备的固定化乙酰胆碱酯酶（AChE）用于监测海水有机磷农药的可行性,研究了固定化酶在海水中的基本性质,如环境适应性、动力学性质、稳定性、对农药响应规律等.结果表明,与溶液酶相比,固定化酶对海水温度、盐度、pH值等因素的适应能力提高;固定化酶分子构象的改变增加了酶与底物之间的空间障碍,米氏常数增加...     

Bridging the gap between ecophysiological and genetic knowledge to assess the adaptive potential of European beech

In this study we aimed to combine knowledge of the ecophysiology and genetics of European beech to assess the potential of this species to adapt to environmental change. Therefore, we performed field and experimental studies on the genetic and ecophysiological functioning of beech. This information was integrated through a coupled genetic–ecophysiological model for individual trees that was parameterized with information derived from our own studies or from the literature. Using the model, we evaluated the adaptive response of beech stands in two ways: firstly, through sensitivity analyses (of initial genetic diversity, pollen dispersal distance, heritability of selected phenotypic traits, and forest management, representing disturbances) and secondly, through the evaluation of the responses of phenotypic traits and their genetic diversity to four management regimes applied to 10 study plots distributed over Western Europe. The model results indicate that the interval between recruitment events strongly affects the rate of adaptive response, because selection is most severe during the early stages of forest development. Forest management regimes largely determine recruitment intervals and thereby the potential for adaptive responses. Forest management regimes also determine the number of mother trees that contribute to the next generation and thereby the genetic variation that is maintained. Consequently, undisturbed forests maintain the largest amount of genetic variation, as recruitment intervals approach the longevity of trees and many mother trees contribute to the next generation. However, undisturbed forests have the slowest adaptive response, for the same reasons.Gene flow through pollen dispersal may compensate for the loss in genetic diversity brought about by selection. The sensitivity analysis showed that the total genetic diversity of a 2 ha stand is not affected by gene flow if the pollen distance distribution is varied from highly left-skewed to almost flat. However, a stand with a prevailing short-distance gene flow has a more pronounced spatial genetic structure than stands with equal short- and long-distance gene flows. The build-up of a spatial genetic structure is also strongly determined by the recruitment interval. Overall, the modelling results indicate that European beech has high adaptive potential to environmental change if recruitment intervals are short and many mother trees contribute to the next generation.The findings have two implications for modelling studies on the impacts of climate change on forests. Firstly: it cannot be taken for granted that parameter values remain constant over a time horizon of even a few generations – this is particularly important for threshold values subject to strong selection, like budburst, frost hardiness, drought tolerance, as used in species area models. Secondly: forest management should be taken into account in future assessments, as management affects the rate of adaptive response and thereby the response on trees and forests to environmental change, and because few forests are unmanaged. We conclude that a coupled ecophysiological and quantitative genetic tree model is a useful tool for such studies.     

Past predation risk induces an intertidal whelk (Nucella lamellosa) to respond to more dilute concentrations of its predator’s scent

Unless sensory control is coupled with developmental flexibility, organisms are unable to produce adaptive phenotypes in response to environmental risk cues. However, empirical examples of adaptive phenotypic plasticity focus largely on development and rarely on sensory control. Here, I ask whether past exposure to predation cues affects an intertidal whelk’s (Nucella lamellosa) sensitivity to the scent of a known predatory crab (Cancer productus). I pre-conditioned whelks for 30 days with the smell of crabs eating other whelks and then, after a period of rest (14 days in fresh seawater free of predator effluent), re-introduced them to different concentrations of waterborne crab scent. Relative to controls, pre-conditioned whelks expressed crab-defences at significantly lower concentrations of crab effluent, suggesting the pre-conditioning reduced their risk–response threshold. Results remind us that the full scope of factors controlling adaptive phenotypic plasticity in natural populations remains underappreciated.     

Prelaying maternal condition modifies the association between egg mass and T cell-mediated immunity in kestrels

Theoretical models of parental care predict differential allocation in relation to the expected fitness of the offspring. As birds must allocate all the resources required for embryonic development in self-contained packages, maternal egg allocation takes a central role in avian life histories. It is predicted that mothers can influence offspring performance by varying the size or composition of their eggs. In this context, T cell-mediated immune response has been revealed as a valuable tool to evaluate fledgling fitness. However, little is known about its relationships to egg mass. I describe a negative association between egg mass and cellular immune response in Eurasian kestrel nestlings (Falco tinnunculus) throughout 3 years. To explore how environmental conditions could mediate this relationship, I experimentally supplied food to females before egg formation in the third study year. I found that this relationship turned to positive in food-supplied females without any effect on egg size. This result shows that environmental conditions before egg formation mediate the relationship between egg mass and future immune response of the nestlings. I suggest that females may be constrained in improving the future immune response of their offspring due to resource allocation trade-offs determined by their pre-laying condition.