氟啶胺对斑马鱼胚胎线粒体氧化磷酸化和多巴胺系统基因表达的干扰效应

杀菌剂氟啶胺是哺乳动物细胞中一种典型的线粒体氧化磷酸化解偶联试剂,极易在鱼体内富集,且对鱼类具有极高的毒性。本文测定了氟啶胺对斑马鱼(Danio rerio)胚胎的96 h半数致死浓度LC50值,并研究了该浓度下氟啶胺对斑马鱼胚胎线粒体呼吸耗氧速率和多巴胺神经通路中关键基因表达的干扰效应。氟啶胺对斑马鱼胚胎的96 h-LC50值为0.5μmol·L~(-1),该浓度下氟啶胺能够导致胚胎发生中轴骨骼发育不全和心脏水肿等畸形现象,这说明该杀菌剂对斑马鱼胚胎具有极高的毒性。在该浓度下,胚胎的基础呼吸速率和ATP产量均受到了显著抑制,这说明氟啶胺在斑马鱼细胞内同样具有解偶联活性,该杀菌剂能够干扰斑马鱼的线粒体氧化磷酸化过程。另外,LC50浓度氟啶胺还能够激活线粒体内锰超氧化物歧化酶基因(sod2)的表达,这说明氟啶胺能够引发线粒体内氧化自由基的产生,从而导致线粒体功能异常。由于多巴胺系统对线粒体能量产生和氧气消耗具有较高的敏感性,因此本文检测了斑马鱼体内多巴胺系统关键基因的转录水平。LC50浓度的氟啶胺能够显著抑制与多巴胺合成有关的酪氨酸羟化酶基因(th)和与多巴胺接收有关的多巴胺受体基因(drd2a)的转录水平,这说明斑马鱼在发育中多巴胺系统是氟啶胺引发神经疾病的有效靶位。一直以来氟啶胺在水环境中的残留是备受关注的环境问题,因此研究氟啶胺对斑马鱼胚胎的毒性作用机制具有重要意义。     

市政污水处理厂二级出水消毒前后对斑马鱼幼鱼的毒性

为了探究消毒副产物(DBPs)的氧化损伤和神经毒性作用,选择幼年斑马鱼作为模式生物,研究了市政污水处理厂二级出水和经次氯酸钠(NaClO)消毒后的二级出水对斑马鱼体内过氧化氢酶(CAT)活性、丙二醛(MDA)含量和乙酰胆碱酯酶(Ach E)活性的影响。结果表明,暴露时间达到10 d时,MDA含量显著高于对照,且消毒后MDA含量增幅(91.43%)显著高于消毒前(44.36%);暴露时间达到15 d时,CAT活性被显著抑制,且消毒后抑制率(40.22%)显著高于消毒前(15.56%);说明消毒后暴露组对斑马鱼的氧化损伤强于消毒前。另外,消毒前后污水对Ach E活性抑制率分别为38.49%和48.50%,说明消毒后污水对斑马鱼的神经毒性更大。因此,经NaClO消毒后的市政污水处理厂二级出水中DBPs对斑马鱼的抗氧化防御系统和神经系统具有潜在影响。     

有机磷酸酯对斑马鱼的早期神经毒性作用研究

国内外研究已证实,有机磷酸酯广泛分布于多种环境介质中,但目前仍缺乏足够的数据阐明有机磷酸酯具有早期神经毒性效应及其可能的毒性作用机制。本研究采用模式动物斑马鱼(Danio rerio)作为研究对象,选择了环境中3种典型的有机磷酸酯类化合物包括磷酸三苯酯(TPP)、2-乙基己基二苯基磷酸酯(EHDPP)和磷酸三(2-氯)乙酯(TCEP),从斑马鱼运动行为、氧化应激和神经发育关键基因的转录等方面阐述有机磷酸酯的早期神经毒性作用及可能的作用机制。研究发现,TPP(0.1和1 mg·L~(-1))、EHDPP(0.2和2 mg·L~(-1))和TCEP(0.5和5 mg·L~(-1))可能通过诱导氧化应激并下调神经发育关键基因(mbp和syn2a)的转录从而显著抑制斑马鱼的运动行为。本研究可以为有机磷酸酯类阻燃剂及其替代产品的生产、使用和危险度评估提供直接依据。     

甲基汞暴露不同时期对大鼠胚胎致畸作用的研究

本文应用全胚胎培养模型探讨了致畸物甲基汞（０４μＧ／ｍｌ）在器官形成早期暴露不同时期后，对大鼠胚胎生长发育的影响。结果显示早期暴露６ｈ，畸胎发生率为３３３％；１２ｈ，绝大多数反映胚胎生长发育和器官形态分化的指标埴均明显降低且５０％的胚胎出现多种畸形表现，例如，神经管未闭、心包积液及脑部形态异常等；暴露２４ｈ和４８ｈ，甲基汞对胚胎发育的抑制作用及诱发的畸胎率匀与１２ｈ的结果类似（ｐ＞００５）；但在晚期暴露１２ｈ，未见胚胎发育异常。结果提示体外培养胚胎对甲基汞的敏感时期约在１—１２ｈ这一期间     

FISH EMBRYOS: PRACTICAL INDICATORS OF ENVIRONMENTAL QUALITY OF SIGNWICANCE TO FISHERIES1

ABSTRACT: Cyto-embryological analyses of fish eggs collected in nature can be a more sensitive indicator of environmental pollution than more typical assays conducted on artificially-spawned eggs. This is because uncertainties associated with artificial spawning and rearing are dispensed with, as well as because of the sensitivity of some cellular and subcellular analyses. At the same time, such measures can provide information on interannual differences in egg viability of importance in elucidating great, unexplained variability in fisheries recruitment. Extensive experience with fish embryos from ocean plankton has led to the choice of a particularly useful, practical suite of observations for different developmental stages. This includes measures of embryo mortality, mutagenicity, teratogenicity, abnormal cell differentiation, and development rate. Atlantic mackerel egg mortality has been determined to be greater in the surface waters of the New York Bight apex and along the New Jersey coast than in less polluted portions of the Bight. Chromosome abnormality of mid-stage embryos was also greater in more impacted areas of the same water mass, as well as in the somatic cells of adult mackerel and winter flounder, and in juvenile and adult windowpane flounder caught in more impacted areas. Mortality and abnormality of the mackerel embryos showed statistical associations with toxic hydrocarbons as measured in plankton, and with heavy metals as measured in sea surface waters. The sensitivity, practicality, and relevance of the cytoembryological studies to population dynamics of resource species make this an important means of monitoring environmental quality.     

Effects of chronic exposure to nonylphenol on locomotor activity and social behavior in zebrafish (Danio rerio)

Nonylphenol(NP),a xenoestrogen ubiquitously found in aquatic ecosystems,is of high environmental concern.The present work assessed the effects of exposure to NP on locomotor activity and social behavior in male and female zebrafish(Danio rerio),to evaluate the possible hazard of NP to fish behavior and to pursue a potential biomarker of NP contamination.Fish were randomly divided into six groups.Five groups were receiving 0.1,1,10,50 and 100 μg/L nominal concentrations of NP for 60 days,respectively.A sixth control group was given the same treatment as the other five groups,but no NP.Locomotor activity,aggressive behavior,group preference and leaving shoal were examined.NP exposure showed marked influence on locomotor activity of the male zebrafish,whereas that of the female was not significantly affected by NP.Aggressive behavior and group preference were significantly affected by NP exposure in both male and female groups.Locomotor activity and aggressive behavior of the male and group preference of both male and female zebrafish were clearly inhibited at 100 μg/L NP.No significant alteration in leaving shoal was observed under NP exposure.The results suggested that changes in locomotor activity and aggressive behavior of the male and group preference of both male and female may be used as an ecologically relevant integrative biomarker of NP contamination.     

PFOS/PFOA对斑马鱼(Danio rerio)胚胎致毒效应研究

采用斑马鱼胚胎毒性测试方法,研究了PFOA/PFOS对斑马鱼的急性毒性和生命早期阶段生长发育的影响.结果表明,PFOS/PFOA对斑马鱼有明显毒性作用,LC50(48 h)分别为1 005 mg/L和107 mg/L,LC50(96 h)分别为499 mg/L和71 mg/L.PFOS/PFOA抑制斑马鱼胚胎发育,可导致胚胎发育畸形,甚至死亡,高浓度(>240 mg/L)PFOS损伤细胞膜,导致胚胎分裂中的细胞发生自溶而卵凝结死亡,抑制胚胎原肠胚的形成.在各种亚致死效应中,脊柱畸形对PFOS暴露最敏感,其EC50=9.14 mg/L,PFOA暴露最敏感亚致死性毒理学终点为96 h孵化,对应EC50=328.0 mg/L.PFOA/PFOS导致胚胎发育延迟,具有发育毒性.     

利用基因芯片探讨五氯酚发育毒性的作用机制

0hpf斑马鱼胚胎经50μg/L五氯酚(PCP)暴露染毒8 h,提取其总RNA,与Affymetrix公司的斑马鱼基因组芯片杂交.发现与对照组相比,染毒样本中1 149个基因的表达显著增强(Signal log ratio1),501个基因的表达显著减弱(Signal log ratio-1).利用Chipinfo、Genmapp等生物信息学软件对差异表达基因进行了基因本体论功能分类和发育调控通路分析,结果显示,显著差异表达的基因涉及抗氧化、信号传导、翻译调节、转录调节等多个分子功能.五氯酚暴露后斑马鱼胚胎发育重要的调控通路BMP信号、ERK通路、FGF信号、Nodal信号的调控基因smad2、smad5、bmp4、bmp7f、lh、n-ras的表达发生了显著变化,Signal logratio分别为4.6、2.1、1.6、1.0、1.3、1.0.这些结果为进一步阐明五氯酚的发育毒性作用机制提供了标志物.     

水溶性CdTe量子点对斑马鱼胚胎发育的影响

本试验以巯基乙酸 (TGA)作为稳定剂合成水溶性CdTe量子点,采用斑马鱼胚胎发育技术,观测0、1、25、50、100、200、300、400 nmol/L各浓度的水溶性CdTe量子点对斑马鱼胚胎发育的影响．记录胚胎发育过程中具有代表性的毒理学终点(自主运动频率、内心率、体长)．结果表明：在胚胎受精后120小时（hours post fertilization）CdTe量子点半数致死浓度（LC50）为185.9 nmol/L．CdTe量子点对斑马鱼胚胎24hpf时1min自主运动频率、48hpf时10s内心率、体长都存在剂量-效应关系．TGA-CdTe能引起斑马鱼胚胎发生各种中毒症状,如心包囊肿、卵黄囊肿、脊柱弯曲、体节减少、心率减慢、黑色素沉积少等异常现象．     

福美双对斑马鱼胚胎Ⅲ型脱碘酶基因表达的影响

福美双是一种二硫代甲氨基甲酸盐类农药,在我国应用较为广泛,但其残留毒性引起广泛重视。试验采用斑马鱼胚胎作为动物模型,探讨了福美双对斑马鱼胚胎的毒性。结果表明福美双导致斑马鱼胚胎孵化率下降,在受精后72 h(72 hpf),对照组的孵化率是100%,1×10-7mol·L-1福美双染毒组的孵化率降至46%,而1×10-6mol·L-1福美双染毒致使孵化率降到0%。III型脱碘酶与斑马鱼的发育和变态息息相关,以上2种浓度的福美双在24 hpf分别增高了III型脱碘酶基因的表达6.71和14.84倍,结果表明福美双具有一定的内分泌搅乱作用,也表明斑马鱼胚胎作为农药安全评价模型的理论可行性。