三氯生和三氯卡班对两栖动物蝌蚪的急性毒性

三氯生(TCS)和三氯卡班(TCC)是个人护理品中常用抗菌剂,在水体中普遍存在,但目前其对两栖动物的毒性研究仍较少。本研究以黑斑蛙蝌蚪和非洲爪蛙蝌蚪为受试生物,研究TCS和TCC对蝌蚪的急性毒性。将处于第一个蝌蚪发育期的黑斑蛙蝌蚪(Gosner 26期)和非洲爪蛙蝌蚪(NF 46期)分别暴露于系列浓度的TCS和TCC,测定其对蝌蚪的半数致死浓度(96 hLC_(50))。结果发现,TCS对黑斑蛙蝌蚪和非洲爪蛙蝌蚪的96 h-LC_(50)分别为441μg·L~(-1)和280μg·L~(-1);TCC对黑斑蛙蝌蚪和非洲爪蛙蝌蚪的96 h-LC_(50)为252μg·L~(-1)和217μg·L~(-1)。这些数据显示TCS和TCC对两种蝌蚪的毒性较高,且对非洲爪蛙蝌蚪毒性均略高于对黑斑蛙蝌蚪的毒性,整体来看TCC的毒性略高于TCS。     

黑斑蛙与非洲爪蟾蝌蚪急性毒性试验方法敏感性的比较

两栖动物蝌蚪急性毒性试验是评价化学品急性毒性的一种方法。以毒死蜱、乙草胺、重铬酸钾和全氟辛烷磺酸盐(PFOS)为测试物,比较了我国本土黑斑蛙(Rana nigromaculata)与国际通用种非洲爪蟾(Xenopus laevis)在蝌蚪急性毒性试验中的敏感性。结果发现：2类蝌蚪分别进行的11次试验中,空白对照组黑斑蛙蝌蚪死亡率(0.9%)远低于非洲爪蟾蝌蚪的死亡率(5.8%);重铬酸钾和PFOS对黑斑蛙蝌蚪的96 h-LC₅₀分别为34.0 mg·L^-1和81.0 mg·L^-1,而对非洲爪蟾蝌蚪的96 h-LC₅₀分别为51.6 mg·L^-1和92.1 mg·L^-1,显示黑斑蛙蝌蚪对这2种化学品的敏感性略高于非洲爪蟾蝌蚪;毒死蜱和乙草胺对黑斑蛙蝌蚪的96 h-LC₅₀分别为0.41 mg·L^-1和4.1 mg·L^-1,而对非洲爪蟾蝌蚪的96 h-LC₅₀分别为0.12 mg·L^-1和3.1 mg·L^-1,显示黑斑蛙蝌蚪对这2种化学品的敏感性略低于非洲爪蟾。鉴于2类蝌蚪对化学品的敏感性存在差异,且黑斑蛙蝌蚪的自然死亡率低,材料更易获得,笔者认为黑斑蛙蝌蚪比非洲爪蟾更适合作为蝌蚪急性毒性试验的材料,用于我国化学品环境管理中的毒性评价。     

3种阿维菌素类药物对无尾两栖类蝌蚪的急性毒性效应（英文）

阿维菌素类药物是一组从土壤链霉菌发酵菌丝中分离出的新型大环内酯类药物,是目前最有效的一类抗虫抗菌的生物农药.采用静态换水法检测阿巴克丁(Abamectin,ABM)、伊维菌素(Ivermectin,IVM)和甲氨基阿维菌素苯甲酸盐(Emamectin benzoate,EMB)3种阿维菌素类农药对黑眶蟾蜍(Duttaphrynus melanostictus)、沼水蛙(Hylarana guentheri)、斑腿泛树蛙(Polypedates megacephalus)和小弧斑姬蛙(Microhyla heymonsi)蝌蚪的急性毒性效应.结果显示,蝌蚪累积的死亡几率与药物浓度间存在显著的剂量效应关系.ABM对4种蝌蚪的96 h半致死浓度(LC_(50))分别为0.042、0.034、0.020和0.014 mg/L;IVM对4种蝌蚪的96 h-LC_(50)分别为0.029、0.012、0.012和0.006 mg/L;EMB对4种蝌蚪的96 h-LC_(50)分别为0.118、0.111、0.122和0.089 mg/L.本研究表明这些农药对两栖动物种群下降可能具有明显的作用,可为了解阿维菌素类药物对两栖动物的毒性提供有益数据.     

全氟辛烷磺酸盐(PFOS)及替代品对两栖类蝌蚪的急性毒性

PFOS及其4种替代品对两栖动物非洲爪蟾和黑斑蛙蝌蚪的急性毒性结果为:用调聚法合成的织物三防整理剂对非洲爪蟾蝌蚪和黑斑蛙蝌蚪的96h-LC50分别为8和21mg·L-1,而PFOS对两种蝌蚪的96h-LC50分别为92和81mg·L-1。此实验结果说明织物三防整理剂的急性毒性高于PFOS。用电解氟化法合成的C4、C6织物三防整理剂和50%的全氟丁基有机铵盐阳离子表面活性剂浓度在100mg·L-1时,对两种蝌蚪都没有毒性。这说明,从急性毒性的角度,C4、C6织物三防整理剂和表面活性剂可作为PFOS的替代品使用,但是织物三防整理剂的急性毒性比PFOS大,作为替代品使用应慎重考虑。另外,PFOS和织物三防整理剂对黑斑蛙蝌蚪的急性毒性与对非洲爪蟾蝌蚪的急性毒性存在差异。出于保护我国本土两栖动物的目的,使用黑斑蛙开展毒性评价比使用非洲爪蟾更有现实意义。     

除草剂阿特拉津溶液中弹琴蛙(Rana adenopleura)蝌蚪的微空间分布

采用扩散系数C等5种分布型指标测定阿特拉津溶液中(ρ1-3/mg L-1:10,20,30)弹琴蛙(Rana adenopleura)蝌蚪(均处于25期和26期,体长范围26-60 mm)在水族箱(l×b×h=40 cm×20 cm×25 cm)中的空间分布模式,结果表明蝌蚪在水族箱中为聚集分布.经多次适合性检验,证明弹琴蛙蝌蚪水族箱中的水平分布呈现负二项分布状态.随着阿特拉津浓度的升高,蝌蚪在水族箱内的聚集度(由负二项分布的k值来表明)逐渐减小(kρ1相似文献   

图像处理在弹琴蛙(Rana adenopleura)蝌蚪生物监测研究中的应用

利用图像处理方法对不同质量浓度的阿特拉津溶液(1mg／L、5mg／L、10mg／L、15me／L)中弹琴蛙(Rana ade-nopleura)蝌蚪行为进行了图像的识别及分析．根据实验结果，利用MATLAB语言编写了弹琴蛙蝌蚪在水族缸中具体分布型判定的程序，采用了负二项分布的参数κ值来反应不同溶液中蝌蚪聚集程度的差异，并作为该指示生物监测阿特拉津水体污染情况的一个指标．结果显示，该程序可如实反映不同污染水体中蝌蚪的聚集程度：经χ^2检验各种水体中蝌蚪均符合负二项分布，同时阿特拉津溶液中蝌蚪的κ值均小于空白对照和丙酮对照，表明阿特拉津溶液的浓度和蝌蚪的聚集程度相关．图9表1参14     

急性铜胁迫对海陆蛙蝌蚪抗氧化效应及金属解毒能力的影响

海陆蛙(Fejervarya cancrivora)是红树林半咸水生境中唯一的两栖动物,为了解铜离子(Cu2+)对该蝌蚪的毒性效应,测定了Cu2+对海陆蛙蝌蚪(38-39期)96 h内半数致死浓度LC50;在此基础上,模拟其野外生存环境,分别设计3个铜暴露组(Cu SO4含量分别为80、160、300μg L-1)和对照组,检测海陆蛙蝌蚪在Cu2+暴露24 h、48 h、72 h、96 h后抗氧化能力、乙酰胆碱酯酶(ACh E)活性及金属硫蛋白(MT)表达量的变化。结果显示,海陆蛙蝌蚪对Cu2+24 h、48 h、72 h、96 h LC50分别为5.69、3.37、1.34、0.95 mg L-1。在急性胁迫试验中,各暴露组蝌蚪体内超氧化物歧化酶(SOD)、ACh E活性以及MT表达均被抑制,在同一暴露时间下,处理组SOD、ACh E活性和MT含量显著低于对照组;而在Cu2+胁迫下,蝌蚪体内脂质过氧化反应加剧,表现为丙二醛(MDA)含量显著增多,且染毒浓度越大、暴露时间越长,MDA含量越多。除ACh E外,其他指标组染毒时间与浓度间具有显著的互作效应。本研究表明海陆蛙可作为红树林生境质量评价的指示物种,其中SOD、ACh E活性及MDA含量可作为重金属Cu2+毒性效应评估较敏感的评价指标。     

异噻唑啉酮类杀菌剂对黑斑蛙胚胎和蝌蚪的急性毒性

异噻唑啉酮类杀菌剂1,2-苯并异噻唑-3-酮(BIT)和甲基异噻唑啉酮(MIT)虽已在多种行业中广泛使用,但目前有关其毒性尤其对水体中生物毒性的数据还较少。鉴于BIT和MIT在水体中普遍存在,本文研究了这两种污染物对两栖动物黑斑蛙胚胎和蝌蚪的急性毒性。黑斑蛙胚胎和蝌蚪分别暴露系列浓度的BIT和MIT,观察化学品对其生长、发育和运动的影响,计算96小时半数致死浓度(96 h-LC50)和96小时半数致畸浓度(96 h-TC50),确定最小生长抑制浓度(MCIG)。结果发现,BIT对黑斑蛙胚胎的96 h-LC50和96 h-TC50分别为2.99 mg·L-1和0.60 mg·L-1,MCIG小于0.40 mg·L-1,对蝌蚪的96 h-LC50为6.44 mg·L-1。MIT对黑斑蛙胚胎的96 h-LC50和96 h-TC50分别为5.30 mg·L-1和2.36 mg·L-1,MCIG为2.59 mg·L-1,对蝌蚪的96 h-LC50为7.58 mg·L-1。根据《化学农药环境安全评价准则报批稿》中两栖动物蝌蚪急性毒性的分级标准,判定BIT和MIT的毒性等级为中等。该毒性数据可为异噻唑啉酮类杀菌剂的环境管理提供参考。     

阿特拉津溶液对弹琴蛙(Rana adenopleura)蝌蚪形态发育的影响

研究了弹琴蛙(Rana adenopleura)蝌蚪在不同阿特拉津浓度(p／mg L^-1：5，10，15，20)溶液中经不同时间处理(10d、20d)后的形态发育特征．结果表明：20d处理组蝌蚪的全长增长率和后肢长增长率低于空白对照组(CKH20)，全长出现负增长，而丙酮对照组(CKacetone)蝌蚪的全长增长率高于CKH2o．实验证明，阿特拉津可抑制蝌蚪的生长和发育，而丙酮却促进蝌蚪的生长．各环境因素的多因素方差分析结果显示，pH和电导率与阿特拉津对蝌蚪的生长、发育作用效应相一致．图2表8参14     

农药引起的两栖动物脑部的变化：亚致死浓度的毒死蜱如何直接影响神经发育

农药虽然可以控制病虫害,但其广泛使用造成自然环境的污染,致使非靶标生物暴露于农药污染环境中。即使低浓度农药暴露也会直接或间接影响水生生物群落。前期人工池塘(中宇宙)研究结果表明痕量毒死蜱(chlorpyrifos, CPF)可改变蝌蚪体态和神经发育。造成这个结果的原因可能为：1)CPF暴露的直接影响;2)农药造成了浮游动物数量下降扰乱食物网。为了明确原因,我们在CPF耐受浮游动物存在的情况下,考察了CPF对两栖动物发育的影响,这种浮游动物是不同营养级别水生生物群落的重要组成部分。豹蛙(Lithobates pipiens)蝌蚪饲养在中宇宙的环境,经过变态期,环境中含有0或1 μg/L CPF,或CPF敏感型浮游动物Daphnia pulex。CPF发育期暴露致使蝌蚪蜕变时视顶盖、延髓、间脑相对更宽,而这一结果与中宇宙中浮游动物种群无关。因此,CPF直接影响大脑发育,与不同营养级别的群落的无关。至于身体形态方面,CPF对无CPF敏感型浮游动物的中宇宙中饲养的蝌蚪蜕变形态没有影响,但在没有CPF污染时,蝌蚪身体形态对浮游动物种群数量很敏感。研究表明,生态水平的低剂量有机磷农药暴露可直接影响脊椎动物的神经发育。 精选自Sara J. McClelland, Randall J. Bendis, Rick A. Relyea, Sarah K. Woodley. Insecticide-induced changes in amphibian brains: How sublethal concentrations of chlorpyrifos directly affect neurodevelopment. Environmental Toxicology and Chemistry,2018,37:2692–2698.
详情请见 https://doi.org/10.1002/etc.4240
     

Complex brood care and reproductive behaviour in captive poison-arrow frogs,Dendrobates pumilio O. Schmidt

Summary Brood care in Dendrobates pumilio not only involves egg attendance and tadpole transport, but also tadpole attendance and feeding. Each tadpole is carried by the attending female to a water-filled bromelial leaf axil and regularly fed on unfertilized eggs. The tadpole responds to an approaching adult with a specialized, conspicuous behavior signalling its presence. Male-male competition includes fighting, egg eating, and male tadpole transport. D. pumilio is the first frog known to feed its free-living larvae.     

Exposure to metals (Ca,K, Mn) and road salt (NaCl) differentially affect development and survival in two model amphibians

ABSTRACT

Human activity has led to widespread chemical alteration of natural environments. Aquatic ecosystems are especially susceptible to chemical changes, including those caused by runoff and invasive species. Here, we examined the effects of water chemistry, specifically sodium chloride as well as three metals (Ca, K, and Mn) known to differ between native and invasive wetland plant species’ leaf tissues, on the development of two model amphibians: the native Northern leopard frog, Lithobates pipiens, and the non-native African clawed frog, Xenopus laevis. We exposed frog eggs to metal treatment solutions and measured time to hatching (TTH), and following hatching, we exposed tadpoles to a lethal concentration of sodium chloride and recorded time to death (TTD). We found that increasing metal concentrations generally resulted in acceleration of TTH for Xenopus tadpoles, but had no effect on leopard frogs. However, increasing metal concentrations (Ca, Mn) increased leopard frog tadpole susceptibility to NaCl (decreased TTD), while increasing metal concentrations (Ca, K) generally resulted in decreased Xenopus tadpole susceptibility to NaCl. Overall, our data suggest that invasive amphibians may be more tolerant to chemical changes than native amphibians, including those driven by the introduction of invasive plant species.     

Male care,mate switching,and future reproductive success in a double-brooded passerine

Summary In species with male parental care, polygyny may reduce the parental effort provided by a male, and hence impose a cost on the fitness of his mates, because of decreased growth, survival or health of offspring. I examined a cost of polygyny in the green dart-poison frog, Dendrobates auratus, a species with male parental care in which both male polygyny and mate guarding by females occurs (Summers 1989). All D. auratus males seen carrying tadpoles in a marked area were followed and the pools where they deposited their tadpoles were recorded. Males frequently deposited more than one tadpole in the same pool (in 25% of the observed depositions a male deposited a tadpole in a pool where he had previously deposited at least one other tadpole). Experiments involving manipulation of tadpole densities in pools typically utilized by D. auratus (calabash husks and treeholes) showed that increasing tadpole number had a strong negative effect on both growth rate and survivorship, indicating that polygyny can impose a cost on the fitness of a male's offspring. Hence, females do face a potential cost, in terms of reduced offspring growth and survivorship, when their mates mate polygynously and care for the offspring of other females.     

Pesticides alter ion transport across frog (Pelophylax kl. esculentus) skin

We have measured, in the edible frog (Pelophylax kl. esculentus), the effect of two fungicides (8-hydroxyquinoline and captan), and four herbicides (DCMU, glyphosate, paraquat, and propachlor) on the short-circuit current, whose value gives an estimate of the net ion transport taking place across isolated skin. Glyphosate and paraquat treatment produced a modest increase in short-circuit current, corresponding to 2.6±0.7 and 4.6±0.8 μA·cm^?2, whereas the other substances had a more sustained effect, ranging from 9.1±0.6 (propachlor) to 14.8±0.9 μA·cm^?2 (captan), which is mainly attributable to an increase in the Na⁺ absorption, and, to a lesser extent, Cl^? secretion. The increase in short-circuit current after pesticide treatment, was partially abolished by AF12198, indomethacin, SC58125, SQ 22536, and W7; these results suggest that pesticides, independently from their chemical structure, induce the release of interleukin-1, which triggers the activity of cyclooxygenase-2, whose products, via a concentration in intracellular cAMP and Ca²⁺ concentration, increase Na⁺ absorption. The resulting Na⁺ disequilibrium must be compensated for by other epithelia, with the only consequence being the dissipation of energy. However, our results are important because they indicate that pesticides interact with the basic cellular machinery, which is responsible for the myriad of biological functions of different cell types.     

Effects of Introduced Salmonids on a Montane Population of Iberian Frogs

Abstract:  Amphibians are declining worldwide because of multiple factors, including human-mediated introduction of fishes into naturally fishless areas. Although several studies have focused on the effect of exotic fishes on native amphibians breeding in ponds or lakes, little is known about their effects on stream-breeding species. We studied the effects of introductions of native brown trout ( Salmo trutta ) and exotic brook trout ( Salvelinus fontinalis ) on the stream-breeding, endemic Iberian frog (  Rana iberica ) in a protected area in central Spain. We assessed occurrence patterns of tadpoles and salmonids and compared habitat use of the three species. We also determined experimentally whether chemical cues from salmonids elicited antipredator behavior in tadpoles. Finally, we assessed the relative influence of tadpole habitat preferences, differences in salmonid species, and invasion geography on tadpole occurrence. Despite widely overlapping habitat preferences, tadpoles and trout did not coexist, with the former restricted to fishless habitats. Tadpoles detected chemical cues from both trout species and reacted by decreasing their activity, although the response toward the native brown trout was stronger. The residual distribution of Iberian frogs in Peñalara is better explained by the geography of fish invasions than by the fish species involved. Measures such as fish extirpation from certain areas, aimed at recovering lost habitat and improving connectivity among remaining populations of Iberian frogs, seem critical for the species' long-term survival in central Spain.     

蔬菜常用农药在地下水中残留风险评估

为明确蔬菜常用农药在地下水中的环境风险,运用China-Pearl和SCI-GROW模型开展地下水环境暴露评估,并根据我国成人和儿童暴露参数推导25种农药预测无效应浓度(PNEC)。研究发现,25种农药PECgw为0~18.340μg·L-1,成年人PNECgw为0.003~19.654 mg·L-1,儿童PNECgw为0.001~23.253 mg·L-1。成年人和儿童的RQgw值均小于1,表明25种农药按照登记用量使用,我国成人和各年龄阶段儿童直接饮用施用农药区域地下水的环境风险可接受。     

Chemical communication in green and golden bell frogs: do tadpoles respond to chemical cues from dead conspecifics?

Captive bred animals often lack the ability of predator recognition and predation is one of the strongest causes of failure of breed and release projects. Several tadpole and fish species respond defensively to chemical cues from injured or dead conspecifics, often referred to as alarm pheromones. In natural conditions and in species that school, the association of chemical cues from predators to alarm pheromones released by attacked conspecifics may lead to the learning of the predator-related danger without experiencing an attack. In the laboratory, this chemical communication can also be used in associative learning techniques to teach naïve tadpoles to avoid specific predators and improve survivorship of released animals. In our experimental trials, tadpoles of the threatened green and golden bell frog (Litoria aurea) did not avoid or decrease their activity when exposed to solutions of conspecific macerate, suggesting that the chemicals released into the water by dead/injured conspecifics do not function as an alarm pheromone. This non-avoidance of dead conspecific chemicals may explain why green and golden bell frog tadpoles have seemingly not developed any avoidance behaviour to the presence of introduced mosquito fish, and may render attempts to teach naïve tadpoles to avoid this novel predator more difficult.     

Consequences of Embryonic UV-B Exposure for Embryos and Tadpoles of the Plains Leopard Frog

Abstract: In organisms with complex life cycles, understanding the effects of environmental change requires investigating the possibility that the effect of such change on one stage will have consequences for other stages. We investigated the effects of embryonic exposure to UV-B radiation on embryo and tadpole development of the plains leopard frog (   Rana blairi ). Embryos were exposed to sunlight filtered to provide two levels of UV-B exposure (e.g., at 310 nm: high exposure is approximately 84% transmittance and low exposure is approximately 58% transmittance). Hatching success of embryos exposed to different UV-B levels did not differ. Tadpoles resulting from exposed embryos were raised at three densities. Growth and development were slower in tadpoles exposed to higher UV-B levels as embryos. Density negatively affected growth and development. Survivorship did not differ among UV-B or density treatments. Our results suggest that even if lethal effects are not exhibited at one stage, sublethal effects may manifest themselves at other stages, possibly affecting the long-term success of exposed individuals and populations.     

涕灭威等三种农药在土壤中的移动性

涕灭威、呋喃丹和拉索三种农药在土壤中的淋溶结果表明，经过３０ｃｍ土柱下渗到收集器中的涕灭威为８８．０％，呋喃丹为６９．１％，拉索为１．８４％；农药在四种土壤中的淋溶速度，砂土＞砂壤土＞粘壤土＞粘土；土壤性质对农药移动的影响比农药自身性质的影响要小。     

Flexible defense strategies: competition modifies investment in behavioral vs. morphological defenses

Competition is predicted to affect the expression of inducible defenses, but because costs of behavioral and morphological antipredator defenses differ along resource gradients, its effects on defenses may depend on the traits considered. We tested the predictions from different defense models in tadpoles of the common frog Rana temporaria, which exhibit both types of defenses. In an outdoor experiment, we exposed the tadpoles to nonlethal predators (Aeshna dragonfly larvae) and to a gradient of intraspecific competition. Morphological responses did not follow any of the expected patterns, since investment in defense was not affected by resource level. Instead, tail depth decreased in the absence of predators. Behavioral defenses followed a state-dependent model. Overall, the defense strategy of the tadpoles revealed a shift from morphological and behavioral defenses at low tadpole density to morphological defense only at high density. This difference probably reflects the different efficiency of the defenses. Hiding is an effective means of defense, but it is unsustainable when resources are scarce. Morphological responses become more important with increasing density to compensate for the increase in behavioral risk-taking. Our results indicate that competition can strongly affect reaction norms of inducible defenses and highlight the importance of integrating ecological parameters that affect the cost-benefit balance of phenotypic plasticity.