外源污染物对蚯蚓毒理作用研究进展

以蚯蚓为模式生物,研究环境污染物的生物效应及其对土壤生态系统的影响,已成为国内外的研究热点.蚯蚓受到污染胁迫时,在分子、细胞和生理水平上都会发生明显的变化,进而影响其存活、生长和繁殖能力,最终引起种群及群落的变化.在总结国内外相关研究基础上,从微观水平、个体水平及生态水平3个方面综述和分析了重金属、农药等外源污染物对蚯蚓毒理作用的研究进展,并对未来的研究方向进行了展望.     

农药对农田蜘蛛生态效应的研究进展

农药对农田蜘蛛的生态效应是进行农田害虫综合防治的生态学基础.本文综述了农田蜘蛛接触和吸收农药的主要途径、农药对蜘蛛的生态效应、蜘蛛对农药的抗性以及农药对蜘蛛的致死效应等研究现状.关于农药对农田蜘蛛亚致死效应的研究,特别是分子、生化、生理、行为等方面的异常,国内外报道不多,因此这方面的研究工作有待于进一步加强.参47     

农药内分泌干扰效应研究进展

农药作为农业生产过程中的一类重要生产资料,主要用作杀虫剂、杀菌剂和除草剂等。由于农药的大量使用,目前在各类农产品及各种环境介质中都能被检测到,对饮食健康和环境安全带来潜在危害。研究发现,许多农药为内分泌干扰物,其能够干扰人类和其他生物体的内分泌系统正常功能。本文在总结国内外相关研究的基础上,对农药内分泌干扰效应的作用机理及筛选模型进行总结,对有机氯、有机磷和拟除虫菊酯等各类农药的内分泌干扰效应研究进展进行综述,并提出深入探究农药致毒作用机制和低剂量下多种农药联合毒性是本领域的重要研究方向。     

农药内分泌干扰效应研究进展

农药作为农业生产过程中的一类重要生产资料,主要用作杀虫剂、杀菌剂和除草剂等。由于农药的大量使用,目前在各类农产品及各种环境介质中都能被检测到,对饮食安全和环境健康带来潜在危害。研究发现,许多农药为内分泌干扰物,其能够干扰人类和其它生物体的内分泌系统正常功能。本文在总结国内外相关研究的基础上,对农药内分泌干扰效应的作用机理及筛选模型进行总结,对有机氯、有机磷和拟除虫菊酯等各类农药的内分泌干扰效应研究进展进行综述,并提出深入探究农药致毒作用机制和低剂量下多种农药联合毒性是本领域的重要研究方向。     

Impact of environmental pollutants on vertebrate thyroid systems

甲状腺激素在脊椎动物新陈代谢、生长发育与繁殖等生理过程中起着重要的调节作用.环境污染物种类和数量不断增加,其中有很多污染物具有环境内分泌干扰的作用.甲状腺对环境污染物具有极敏感的反应,污染物不仅会引起滤泡及滤泡细胞大小、滤泡细胞数量和滤泡腔中胶质含量的改变,影响到甲状腺激素合成、分泌、转运以及代谢中多种酶的表达和活性变化,还参与和甲状腺激素的竞争性结合,进而影响到机体中由甲状腺激素调节的各项生理功能,甚至会导致机体趋于死亡.由于两栖类幼体——蝌蚪的变态发育阶段直接受到甲状腺激素的调控,现已被确认为筛选和研究环境内分泌干扰物的首选生物检测指示动物.     

36种典型除草剂对绿藻的毒性研究

近年来,农药对生态系统的初级生产者——藻类的毒性及其生态毒理学研究引起了国内外学者的广泛关注。除草剂在生产中广泛应用,对藻类的毒性作用最强,其毒性效应远高于杀虫剂和杀菌剂。论文选择市场上具有典型代表性的36种除草剂原药,分析解读除草剂在国内的登记情况,以及在作物、旱田和水田的使用情况;明晰对藻类生长抑制急性毒性效应。结果表明:1)除草剂的作用方式和化学类别对绿藻毒性影响显著;对于抑制植物细胞分裂和作用于植物叶绿体的除草剂对绿藻毒性均较高,以人工合成植物生长素为代表的除草剂对绿藻毒性均较低;2)相同作用方式,不同化学类别的除草剂,对单一绿藻的毒性差异明显。在水稻上获得登记的除草剂对藻类毒性整体低于在旱田获得登记的除草剂对藻类的毒性。开展多种农药对水生生态毒性的研究,为农药的合理安全使用、农药在淡水环境中的生态效应评价以及保护淡水生态系统提供科学依据。     

农药类化合物对鱼类脂质代谢的影响及机制研究进展

由于农药的广泛使用,目前许多农药类化学物质在水生生态系统中被检出,造成水环境污染,影响水生非靶生物的健康。脂质在鱼类生长发育中发挥着重要作用,近年来大量研究表明农药暴露能够干扰鱼类脂质代谢,导致脂质水平紊乱。本文在介绍农药污染现状基础上,从干扰脂质消化吸收、合成、分解和转运等过程综述了农药类化合物对鱼类脂质代谢的干扰效应及机制。以期为今后进一步探究农药的脂代谢毒性作用及其安全性评价提供更多的理论参考。     

纳米银对无脊椎动物毒性效应的研究进展

纳米银（AgNPs）因优良的抗菌特性,已成为全球使用量最多的纳米材料.随着AgNPs使用量的增多,其不可避免流入环境中,对生态系统造成危害.无脊椎动物是动物类群重要的组成部分,本文主要从累积效应、急性毒性、生长发育毒性、组织病症、生殖毒性、遗传毒性和回避行为等方面总结了AgNPs对无脊椎动物的影响和潜在毒性机制,介绍了AgNPs对无脊椎动物毒性的影响因素,分析了AgNPs关于无脊椎动物毒性研究的不足并对研究趋势进行了展望.本文旨在为AgNPs对无脊椎动物的毒性研究以及AgNPs的安全生产和合理使用提供参考.     

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。     

草铵膦和草甘膦在水环境中的行为和毒性效应研究进展

草铵膦和草甘膦均为灭生性广谱除草剂,具有低毒、高效的特点,是目前世界上使用最多的2种有机磷类除草剂,广泛应用于防除果园、非耕地等的杂草.在世界范围内广泛使用导致这2种农药越来越多地进入环境,尤其是水环境中.由于草铵膦和草甘膦在水中的溶解度大,且在水溶液中较稳定,目前在多地的水体中均检出2种农药残留.随着对草铵膦和草甘膦毒性研究的深入,有越来越多的研究结果显示这2种农药对水生生物存在一定的毒性.针对目前草铵膦和草甘膦在水体中的环境行为和毒性效应(包括对鱼类、藻类和其他水生生物的毒性效应)研究进展进行了总结,旨为草铵膦和草甘膦在水环境中的环境行为和对水生生物的毒性研究提供有益借鉴,为2种农药的合理使用提供参考.     

Value of Artificial Habitats for Amphibian Reproduction in Altered Landscapes

Abstract:  Installation and maintenance of stormwater ponds to detain and treat runoff from impervious surfaces is a common method of stormwater control in developed areas. That these ponds capture pollutants, however, is of concern for wildlife species that use the ponds, particularly pond-breeding amphibians. To assess the relative contribution of stormwater ponds to the persistence of amphibian populations in suburban landscapes, we compared amphibian use of stormwater ponds and other available wetlands in suburban and forested watersheds. We surveyed three suburban and three primarily forested first-order watersheds to identify all potential wetlands that might serve as breeding sites for pond-breeding amphibians. We performed call, egg-mass, and larval surveys to measure breeding effort at each wetland in spring and summer 2007 and 2008. In suburban watersheds most (89%) of the wetlands that had breeding activity were either stormwater ponds or otherwise artificial. This pattern was also evident in the forested watersheds, where amphibians were primarily found breeding in wetlands created by past human activity. Late-stage larvae were found only in anthropogenic wetlands in all study areas because the remaining natural wetlands did not hold water long enough for larvae to complete development. Our results suggest that in urban and suburban landscapes with naturally low densities of wetlands, wetlands created by current or historic land uses may be as important to amphibian conservation as natural wetlands or pools and that management strategies directed at urban and suburban landscapes should recognize and incorporate human-created wetlands.     

Investigating potential for effects of environmental endocrine disrupters on wild populations of amphibians in UK and Japan: status of historical databases and review of methods.

Concern over global declines among amphibians has resulted in increased interest in the effects of environmental contaminants on amphibian populations, and more recently, this has stimulated research on the potential adverse effects of environmental endocrine disrupters in amphibians. Laboratory studies of the effects of single chemicals on endocrine-relevant endpoints in amphibian, mainly anuran, models are valuable in characterizing sensitivity at the individual level and may yield useful bioassays for screening chemicals for endocrine toxicity (for example, thyroid disrupting activity). Nevertheless, in the UK and Japan as in many other countries, it has yet to be demonstrated unequivocally that the exposure of native amphibians to endocrine disrupting environmental contaminants results in adverse effects at the population level. Assessing the potential of such effects is likely to require an ecoepidemiological approach to investigate associations between predicted or actual exposure of amphibians to (endocrine disrupting) environmental contaminants and biologically meaningful responses at the population level. In turn, this demands recent but relatively long-term population trend data. We review two potential sources of such data for widespread UK anurans that could be used in such investigations: records for common frogs and common toads in several databases maintained by the Biological Records Centre (UK Government Centre for Ecology and Hydrology), and adult toad count data from 'Toads on Roads' schemes registered with the UK wildlife charity 'Froglife'. There were little abundance data in the BRC databases that could be used for this purpose, while count data from the Toads on Roads schemes is potentially confounded by the effects of local topology on the detection probabilities and operation of nonchemical anthropogenic stressors. For Japan, local and regional surveys of amphibians and national ecological censuses gathering amphibian data were reviewed to compile survey methodologies and these were compared with methods used in the UK and other countries. Substantial consensus exists in amphibian survey methodologies and this should be exploited in the initiation of coordinated monitoring programs for widespread and common anuran amphibians in Japan and the UK to generate long-term robust and standardized population trend data. Such data would support comparative ecoepidemiological assessments of the impact of environmental endocrine disrupters in these two cooperating countries.     

Possible Environmental Factors Underlying Amphibian Decline in Eastern Puerto Rico: Analysis of U.S. Government Data Archives

Abstract: The past three decades have seen major declines in populations of several species of amphibians at high elevations in eastern Puerto Rico, a region unique in the humid tropics because of the degree of environmental monitoring that has taken place through the efforts of U.S. government agencies. I examined changes in environmental conditions by examining time-series data sets that extend back at least into the 1980s, a period when frog populations were declining. The data include forest cover; annual mean, minimum, and maximum daily temperature; annual rainfall; rain and stream chemistry; and atmospheric-dust transport. I examined satellite imagery and air-chemistry samples from a single National Aeronautics and Space Administration aircraft flight across the Caribbean showing patches of pollutants, described as thin sheets or lenses, in the lower troposphere. The main source of these pollutants appeared to be fires from land clearing and deforestation, primarily in Africa. Some pollutant concentrations were high and, in the case of ozone, approached health limits set for urban air. Urban pollution impinging on Puerto Rico, dust generation from Africa ( potential soil pathogens), and tropical forest burning ( gaseous pollutants) have all increased during the last three decades, overlapping the timing of amphibian declines in eastern Puerto Rico. None of the data sets pointed directly to changes so extreme that they might be considered a direct lethal cause of amphibian declines in Puerto Rico. More experimental research is required to link any of these environmental factors to this problem.     

Citation Rate and Perceived Subject Bias in the Amphibian‐Decline Literature

Abstract: As a result of global declines in amphibian populations, interest in the conservation of amphibians has grown. This growth has been fueled partially by the recent discovery of other potential causes of declines, including chytridiomycosis (the amphibian chytrid, an infectious disease) and climate change. It has been proposed that researchers have shifted their focus to these novel stressors and that other threats to amphibians, such as habitat loss, are not being studied in proportion to their potential effects. We tested the validity of this proposal by reviewing the literature on amphibian declines, categorizing the primary topic of articles within this literature (e.g., habitat loss or UV‐B radiation) and comparing citation rates among articles on these topics and impact factors of journals in which the articles were published. From 1990 to 2009, the proportion of papers on habitat loss remained fairly constant, and although the number of papers on chytridiomycosis increased after the disease was described in 1998, the number of published papers on amphibian declines also increased. Nevertheless, papers on chytridiomycosis were more highly cited than papers not on chytridiomycosis and were published in journals with higher impact factors on average, which may indicate this research topic is more popular in the literature. Our results were not consistent with a shift in the research agenda on amphibians. We believe the perception of such a shift has been supported by the higher citation rates of papers on chytridiomycosis.     

Amphibian Encounter Rates on Roads with Different Amounts of Traffic and Urbanization

Abstract: Although amphibians have relatively high rates of road mortality in urban areas, the conditions under which traffic threatens the survival of local amphibian populations remain unclear. In the Sandhills region of North Carolina (U.S.A.), we counted living and dead amphibians along two transects (total length 165 km) established on roads in areas with varying degrees of urbanization. We found 2665 individuals of 15 species, and amphibian encounter rates declined sharply as traffic and urban development increased. Regression‐tree models indicated that 35 amphibians/100 km occurred on roads with <535 vehicles/day, whereas the encounter rate decreased to only 2 amphibians/100 km on roads with >2048 vehicles/day. Although mortality rate peaked at higher traffic levels (47% dead on roads with >5200 vehicles/day), the number of dead amphibians was highest at low levels of traffic. This suggests that areas where amphibian mortality is concentrated may actually contain the largest populations remaining on a given road transect.     

Relation of Terrestrial-Breeding Amphibian Abundance to Tree-Stand Age

There is a lack of research on the effects of logging on Canadian amphibians. We compared the abundance of terrestrial salamanders in old-growth forests with that in young and mature post-harvest stands. We also measured habitat features of amphibians and contrasted these with old-growth and harvested stands to assess the effects of forest harvest. Quadrat searches demonstrated that clearcut harvesting reduces terrestrial amphibian populations by up to 70% in coastal old-growth forests. We suggest that this reduction results from a decrease in availability of moist microhabitats. Salamander densities within 10 meters of streams in managed stands were similar to those near and away from streams in old growth. We recommend that forest managers recognize the needs of terrestrial amphibians and help maintain amphibian populations by preserving cool, moist habitats. This can be accomplished within cutblocks by (1) maintaining an even distribution of logs and snags as stable, moist microhabitats; (2) retaining some understory as sources of shade, and (3) preserving streamside buffers. Managers must also ensure some level of landscape connectivity to enable climate-sensitive amphibians to disperse and recolonize marginal habitats.     

A Meta-Analysis of the Effects of Ultraviolet B Radiation and Its Synergistic Interactions with pH, Contaminants, and Disease on Amphibian Survival

Abstract:  Human alterations to natural systems have resulted in a loss of biological diversity around the world. Amphibian population losses have been more severe than those of birds and mammals. Amphibian population declines are likely due to many factors including habitat loss, disease, contaminants, introduced species and ultraviolet-B (UVB) radiation. The effect of UVB, however, varies widely among species and can vary within populations of the same species or at different life-history stages. This variation has often led to opposing conclusions about how UVB affects amphibians. We used meta-analysis techniques to explore the overall effects of UVB radiation on survival in amphibians. We also used recently developed factorial meta-analytic techniques to quantify potential interactions between UVB radiation and other stressors on amphibians. Ultraviolet-B radiation reduced survival of amphibians by 1.9-fold compared with shielded controls. Larvae were more susceptible to damage from UVB radiation compared with embryos, and salamanders were more susceptible compared with frogs and toads. Furthermore, UVB radiation interacted synergistically with other environmental stressors and resulted in greater than additive effects on survival when 2 stressors were present. Our results suggest that UVB radiation is an important stressor in amphibians, particularly in light of potential synergisms between UVB and other stressors in amphibian habitats.     

Environmental Determinants of Recent Endemism of Batrachochytrium dendrobatidis Infections in Amphibian Assemblages in the Absence of Disease Outbreaks

The inconsistent distribution of large‐scale infection mediated die‐offs and the subsequent population declines of several animal species, urges us to understand how, when, and why species are affected by disease. It is often unclear when or under what conditions a pathogen constitutes a threat to a host. Often, variation of environmental conditions plays a role. Globally Batrachochytrium dendrobatidis (Bd) causes amphibian declines; however, host responses are inconsistent and this fungus appears equally capable of reaching a state of endemism and subsequent co‐existence with native amphibian assemblages. We sought to identify environmental and temporal factors that facilitate host–pathogen coexistence in northern Europe. To do this, we used molecular diagnostics to examine archived and wild amphibians for infection and general linear mixed models to explore relationships between environmental variables and prevalence of infection in 5 well‐sampled amphibian species. We first detected infection in archived animals collected in 1999, and infection was ubiquitous, but rare, throughout the study period (2008–2010). Prevalence of infection exhibited significant annual fluctuations. Despite extremely rare cases of lethal chytridiomycosis in A. obstetricans, Bd prevalence was uncorrelated with this species’ population growth. Our results suggest context dependent and species‐specific host susceptibility. Thus, we believe recent endemism of Bd coincides with environmentally driven Bd prevalence fluctuations that preclude the build‐up of Bd infection beyond the critical threshold for large‐scale mortality and host population crashes. Determinantes Ambientales del Endemismo Reciente de Infecciones de Batrachochytrium dendrobatidis en Conjuntos de Anfibios en Ausencia de Brotes de Enfermedades Spitzen et al.     

A test of the substitution–habitat hypothesis in amphibians

Most examples that support the substitution‐habitat hypothesis (human‐made habitats act as substitutes of original habitat) deal with birds and mammals. We tested this hypothesis in 14 amphibians by using percentage occupancy as a proxy of habitat quality (i.e., higher occupancy percentages indicate higher quality). We classified water body types as original habitat (no or little human influence) depending on anatomical, behavioral, or physiological adaptations of each amphibian species. Ten species had relatively high probabilities (0.16–0.28) of occurrence in original habitat, moderate probability of occurrence in substitution habitats (0.11–0.14), and low probability of occurrence in refuge habitats (0.05–0.08). Thus, the substitution–habitat hypothesis only partially applies to amphibians because the low occupancy of refuges could be due to the negligible human persecution of this group (indicating good conservation status). However, low occupancy of refuges could also be due to low tolerance of refuge conditions, which could have led to selective extinction or colonization problems due to poor dispersal capabilities. That original habitats had the highest probabilities of occupancy suggests amphibians have a good conservation status in the region. They also appeared highly adaptable to anthropogenic substitution habitats.