Effects of rare earth elements La and Yb on the morphological and functional development of zebrafish embryos

In recent years, with the wide applications and mineral exploitation of rare earth elements, their potential environmental and health effects have caused increasing public concern. Effect of rare earth elements La and Yb on the morphological and functional development of zebrafish embryos were studied. The embryos were exposed to La³⁺ or Yb³⁺ at 0, 0.01, 0.1, 0.3, 0.5 and 1.0 mmol/L, respectively. Early life stage parameters such as egg and embryo mortality, gastrula development, tail detachment, eyes, somite formation, circulatory system, pigmentation, malformations, hatching rate, length of larvae and mortality were investigated. The results showed La³⁺ and Yb³⁺ delayed zebrafish embryo and larval development, decreased survival and hatching rates, and caused tail malformation in a concentration-dependent way. Moreover, heavy rare-earth ytterbium led to more severe acute toxicity of zebrafish embryo than light rare-earth lanthanum.     

双酚A及其类似物对斑马鱼胚胎及幼鱼的毒性效应

为探讨双酚A及其类似物对鱼类早期生长发育的毒性效应,研究了双酚A及其7种类似物对斑马鱼胚胎及仔鱼的毒性效应。通过对胚胎的孵化率、心率、仔鱼体长等指标进行测定分析,结果显示:(1)双酚A及其7种类似物都可使斑马鱼胚胎出现心包水肿、卵黄囊肿、脊柱弯曲和尾部弯曲等症状。(2)综合考虑斑马鱼78 hpf胚胎心率、120 hpf胚胎孵化率及7 dpf仔鱼体长抑制率等指标,8种受试物中双酚P(BPP)的毒性最大,其次是双酚AP(BPAP)、双酚AF(BPAF)、双酚Z(BPZ),然后是双酚A(BPA)、双酚B(BPB)、双酚F(BPF),双酚S(BPS)的毒性最小,每种受试物的浓度与受精卵的孵化率、仔鱼心率呈明显负相关关系,与体长抑制率呈明显正相关关系。8种受试物毒性与辛醇-水分配系数(log K_(OW))呈正相关关系,log K_(OW)越大毒性则越大。     

铅和得克隆联合暴露对斑马鱼胚胎的神经毒性作用

以斑马鱼(Danio rerio)为研究对象,探讨铅(Pb)、得克隆(DP)及二者联合急性暴露对斑马鱼胚胎的神经毒性作用。结果表明,Pb(5、20μg·L~(-1))和DP(15、60μg·L~(-1))单独暴露均会引起斑马鱼自主运动频率增加,触摸反应能力和自由游泳活力下降,并且抑制初级运动神经元的生长,加剧尾部细胞凋亡。但与20μg·L~(-1)Pb单独暴露相比,高剂量联合暴露(20μg·L~(-1)Pb+60μg·L~(-1)DP)使斑马鱼的自主运动频率显著降低(P0.05),触摸反应能力和自由游泳活力显著增强(P0.05),初级运动神经元轴突长度显著增加(P0.05),尾部细胞凋亡减少。与5μg·L~(-1)Pb单独暴露相比,低剂量联合暴露(5μg·L~(-1)Pb+15μg·L~(-1)DP)也显著减少斑马鱼尾部的细胞凋亡(P0.05)。上述结果表明,Pb或DP单独暴露对斑马鱼均可引起神经毒性作用;但二者联合暴露对斑马鱼自主运动、触摸反应以及自由游泳活力的影响则表现为拮抗作用。     

CdSe/ZnS量子点对稀有鮈鲫胚胎发育的影响及其氧化应激作用

本研究以稀有鮈鲫(Gobiocypris rarus)为对象,研究了不同浓度CdSe/ZnS量子点(QDs)暴露下,稀有鮈鲫胚胎发育过程中自主运动频率、内心率和体长的变化,以及利用体内超氧化物歧化酶(SOD)和丙二醛(MDA)作为毒性指标,反映CdSe/ZnS QDs暴露对稀有鮈鲫胚胎发育的氧化应激作用.结果显示:CdSe/ZnS QDs对稀有鮈鲫胚胎72 hpf(hours post fertilization)的半致死浓度(LC50)为319.629 nmol·L-1,96 hpf的半致畸浓度(EC50)为203.312 nmol·L-1.CdSe/ZnS QDs暴露不仅影响稀有鮈鲫胚胎死亡率、畸形率、自主运动频率、孵化时间和孵化率,而且使其内心率减缓、体长缩短,导致胚胎卵凝结,心包囊肿,出现脊椎弯曲等多种毒性现象.同时发现,CdSe/ZnS QDs暴露导致稀有鮈鲫体内MDA含量增加以及SOD活力的降低.这表明CdSe/ZnS QDs对稀有鮈鲫胚胎发育具有致畸、致死作用,而氧化应激可能是引起其胚胎致畸、致死的重要机制之一.     

氯苯和间甲酚对斑马鱼胚胎和仔鱼联合毒理效应研究

方法:采用斑马鱼胚胎和仔鱼发育技术,分别用不同浓度的氯苯和间甲酚混合液对斑马鱼胚胎和仔鱼进行暴露试验。结果:两种受试物联合对斑马鱼胚胎和仔鱼发育表现不同的联合毒性。0hpf染毒主要表现为:对24 h胚胎尾部延展为拮抗作用,48 h水肿、72 h孵化和畸形均为协同作用;48 h对仔鱼毒性为由相加作用向拮抗作用的转变,在24 h、72 h和96 h联合毒性均为协同作用。结论:氯苯和间甲酚联合作用对斑马鱼胚胎和仔鱼存在毒性。     

Converging hazard assessment of gold nanoparticles to aquatic organisms

The gold nanoparticles (Au-NPs) are being increasingly used because of their huge diversity of applications, and consequently, elevated levels in the environment are expected. However, due to their physico-chemical properties and functionalization a high variety of Au-NPs can be found, and complete toxicological information for each type of Au-NPs still lacks, and even, the toxicological information for the same species is sometimes contradictory. Therefore, hazard assessment should be done case by case. Hence, the objective of this study was to obtain ecotoxicological information of the same Au-NPs in aquatic organisms and to find a rationale for Au-NPs toxicity. For such a purpose, bare and hyaluronic acid capped Au-NPs (12.5 nm) along with Au-NPs bulk material were tested on freshwater algae, Daphnia and zebrafish. Results showed that while gold nanoparticles were found to be harmless to the tested organisms, the soluble gold showed to be toxic to algae and Daphnia, with an LC₅₀ between 1 and 2 mg L⁻¹. Comparing our results with those gathered in the literature, it appears that a common hazard assessment of Au-NPs on the studied organisms can be elucidated.     

Acute toxicity of aromatic and non-aromatic fractions of naphthenic acids extracted from oil sands process-affected water to larval zebrafish

The toxicity of oil sands process-affected water (OSPW) has regularly been attributed to naphthenic acids, which exist in complex mixtures. If on remediation treatment (e.g., ozonation) or on entering the environment, the mixtures of these acids all behave in the same way, then they can be studied as a whole. If, however, some acids are resistant to change, whilst others are not, or are less resistant, it is important to establish which sub-classes of acids are the most toxic.     

Toxicological effect of MPA-CdSe QDs exposure on zebrafish embryo and larvae

Cadmium selenium (CdSe) quantum dots (QDs) are semiconductor nanocrystals that hold wide range of applications and substantial production volumes. Due to unique composition and nanoscale properties, their potential toxicity to aquatic organisms has increasingly gained a great amount of interest. However, the impact of CdSe QDs exposure on zebrafish embryo and larvae remains almost unknown. Therefore, the lab study was performed to determine the developmental and behavioral toxicities to zebrafish under continuous exposure to low level CdSe QDs (0.05-31.25 mg L⁻¹) coated with mercaptopropionic acid (MPA). The results showed MPA-CdSe exposure from embryo to larvae stage affected overall fitness. Our findings for the first time revealed that: (1) The 120 h LC₅₀ of MPA-CdSe for zebrafish was 1.98 mg L⁻¹; (2) embryos exposed to MPA-CdSe resulted in malformations incidence and lower hatch rate; (3) abnormal vascular of FLI-1 transgenic zebrafish larvae appeared after exposure to MPA-CdSe including vascular junction, bifurcation, crossing and particle appearance; (4) larvae behavior assessment showed during MPA-CdSe exposure a rapid transition from light-to-dark elicited a similar, brief burst and a higher basal swimming rate; (5) MPA-CdSe induced embryos cell apoptosis in the head and tail region. Results of the observations provide a basic understanding of MPA-CdSe toxicity to aquatic organisms and suggest the need for additional research to identify the toxicological mechanism.     

Interference with xenobiotic metabolic activity by the commonly used vehicle solvents dimethylsulfoxide and methanol in zebrafish (Danio rerio) larvae but not Daphnia magna

Organic solvents, such as dimethylsulfoxide (DMSO) and methanol are widely used as vehicles to solubilise lipophilic test compounds in toxicity testing. However, the effects of such solvents upon innate detoxification processes in aquatic organisms are poorly understood. This study assessed the effect of solvent exposure upon cytochrome P450 (CYP)-mediated xenobiotic metabolism in Daphnia magna and zebrafish larvae (4 d post fertilisation). Adult D. magna were demonstrated to have a low, but detectable, metabolism of ethoxyresorufin in vivo and this activity was not modulated by pre-exposure to DMSO or methanol (24 h, up to 0.1% and 0.05% v/v, respectively). In contrast, the metabolism of ethoxyresorufin in zebrafish larvae was significantly reduced by both solvents (0.1% and 0.05% v/v, respectively) after 24 h of exposure. In zebrafish, these observed decreases in activity towards ethoxyresorufin were accompanied by decreased expression of a variety of genes coding for drug metabolising enzymes (corresponding to CYP1, CYP2, CYP3 and UDP-glucuronyl transferase [UGT] family enzymes), measured by quantitative PCR. Reduction of gene expression and CYP1 enzyme activities by methanol (0.05% v/v) in zebrafish larvae was partially reversed by co-exposure with Aroclor 1254 (100 μg L⁻¹). Overall this study suggests that relatively low concentrations of organic solvents can impact upon the biotransformation of certain xenobiotics in zebrafish larvae, and that this warrants consideration when assessing compounds for metabolism and toxicity in this species.     

Cu2+和Cd2+对斑马鱼胚胎早期发育的联合毒性

采用斑马鱼胚胎早期发育技术,测定Cu2+和Cd2+ 2种重金属对胚胎发育的毒性效应. 以24 h致死和72 h胚胎孵化抑制为毒性终点,2种重金属的剂量-效应曲线可用Weibull函数或Logit函数有效描述,由最佳拟合函数计算得出半数致死浓度(LC₅₀)或半数效应浓度(EC₅₀)为毒性效应的评价标准,2个毒性终点的重金属毒性大小顺序均为Cu2+>Cd2+. 应用浓度加和(CA)与独立作用(IA)2种模型,对72 h孵化抑制率的无观测效应浓度(NOEC)配比混合物的联合毒性作用进行了预测,通过混合物试验观测数据的95%置信区间与CA模型和IA模型预测的剂量-效应曲线进行比较分析表明,2种模型都可以有效预测斑马鱼胚胎孵化的联合毒性.