迷迭香酸对硫酸铜致斑马鱼胚胎毒性的抑制作用

本文探讨硫酸铜(CuSO_4)对斑马鱼(Danio rerio)胚胎发育的毒性效应,使用迷迭香酸(RA)抑制CuSO_4对斑马鱼胚胎发育的毒性并探讨其作用机制。收集受精后1 h(1 hpf)的斑马鱼胚胎暴露于不同浓度的CuSO_4溶液,或含有不同浓度迷迭香酸的CuSO_4溶液,对照组培养在E3培养液中,观察胚胎死亡、孵化及畸形情况,计算胚胎死亡率、孵化率和畸形率;以活性氧(ROS)荧光探针DCFH-DA染色法检测迷迭香酸保护下胚胎的活性氧水平。对实验数据进行方差分析。结果显示:(1)CuSO_4浓度超过一定量时能诱导斑马鱼胚胎死亡和畸形,胚胎孵化率也降低。CuSO_4对96 hpf斑马鱼胚胎的半致死浓度(LC50)为7.7μmol/L,半致畸浓度(EC50)为1.9μmol/L。(2)在96 hpf,迷迭香酸与8μmol/L CuSO_4共同处理组斑马鱼胚胎的死亡率明显降低,孵化率升高。迷迭香酸与1.6μmol/LCuSO_4共同处理组斑马鱼胚胎的畸形率降低。(3)CuSO_4单独处理组的活性氧含量明显高于迷迭香酸与CuSO_4共同处理组和对照组。结果表明,CuSO_4暴露对斑马鱼胚胎发育的毒性效应可能与活性氧升高导致的氧化应激相关;迷迭香酸抑制CuSO_4对斑马鱼胚胎发育的毒性作用,可能与减少活性氧生成有关。     

五氯酚对斑马鱼胚胎的毒性效应研究

采用斑马鱼胚胎发育技术,对环境激素类物质五氯酚的毒性进行测定,结果表明,五氯酚(PCP)对胚胎的特定作用时间段是卵产出至发育6 h之内;PCP对胚胎发育有明显的抑制作用,会造成胚胎发育的畸形或死亡,不同时间染毒产生的可观察毒理学终点各异;随着PCP对发育48 h斑马鱼胚胎作用时间的减短,其致死效应敏感性降低,其中0 hpf组的LC0值最小,为70.8μg·L^-1,24hpf组LC0值最大,为831.8μg·L^-1;斑马鱼胚胎对孵化后0时染毒的PCP最为敏感,PCP对胚胎产生急性毒性效应的敏感指标:心胞囊肿、血液循环障碍、无心律＞孵化率降低＞停滞发育作用;斑马鱼胚胎最敏感的指标为48 h血液循环障碍和48 h半致死效应.     

迷迭香酸对氯化镉致斑马鱼胚胎发育毒性的保护作用北大核心CSCD

通过考察氯化镉(CdCl2)对斑马鱼胚胎发育的毒性效应及迷迭香酸(rosmarinic acid,RA)的干预作用,探讨镉的发育毒性机理。将受精1 h后的斑马鱼胚胎暴露于不同浓度的CdCl2或含不同浓度RA的CdCl2溶液中,观察胚胎死亡、孵化及幼鱼畸形的情况。采用吖啶橙染色,定性观察胚胎细胞凋亡情况;以单细胞凝胶电泳法检测胚胎细胞的DNA损伤;以活性氧(reactive oxygen species,ROS)荧光探针DCFH-DA染色法检测胚胎的ROS水平,硫代巴比土酸比色法测定胚胎脂质过氧化水平,5,5-二硫二硝基苯甲酸比色法测定胚胎的还原谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)水平;光泽精化学发光法检测胚胎还原型辅酶(nicotinamide adenine dinucleotide phosphate,NADPH)Ⅱ氧化酶(NADPH oxidase,Nox)活性。结果显示,RA浓度依赖性地抑制了CdCl2诱导的胚胎死亡和幼鱼畸型,同时提高了胚胎孵化率。RA可浓度依赖性地改善CdCl2诱导的胚胎ROS和MDA(malonic dialdehyde)水平升高、GSH/GSSG比值降低和Nox活性升高,抑制CdCl2诱导的胚胎细胞凋亡。RT-PCR结果显示,RA对CdCl2诱导的胚胎Cu/Zn-Sod基因表达上调和Bcl-2/Bax水平下调也有明显改善作用。结果说明,CdCl2对斑马鱼胚胎发育具有毒性,可活化Nox,促进ROS生成,造成胚胎细胞氧化胁迫损伤以至胚胎细胞凋亡,而RA可抑制Nox活化,改善氧化胁迫状态,从而对CdCl2的发育毒性起保护作用。     

X射线照射成熟金鱼对于仔鱼胚胎发育的影响

成熟金鱼受1,000伦琴X射线照射后,所产的卵降低了受精率及孵化率,延长了孵化时间。在雌雄同时照射的一组中,孵化时胚胎全部是畸形,受照射雌鱼与正常雄鱼交配所产仔鱼孵化时有40%以上为畸形。畸形胚胎的外部变态为胸腔膨大,卵黄囊积聚体液,脊尾短或弯曲,头部分化不完整,眼分化不完整或缺少色素,下颚扩大等。X射线影响下,胚胎产生的主要缺陷为神经系统特别是脑部和尾部的组成物质受损伤,这些结果表明:胚胎的分化可能在生殖细胞时期已开始,生殖细胞受到了损伤,影响了某些控制以后器官分化的物质,使受精后细胞的分化发生了失调,得不到正常的发育所致。     

UVB影响中华大蟾蜍早期胚胎发育的初步研究

为了研究UVB对两栖类动物早期胚胎发育的影响,以中华大蟾蜍为研究对象,用UVB分别以不同强度和不同时间照射其二细胞期胚胎,观察记录胚胎的发育过程、统计死亡率并在形态学上对UVB照射诱导的畸胚进行分析。结果表明,30μW／cm^2强度的UVB分别照射二细胞期胚胎20s、60s和80μW／cm。强度分别照射20s、60s、120s后,对中华大蟾蜍早期胚胎发育有促进作用,使发育过程中的死亡率降低,畸胚出现的类型较少且畸变程度低;80μW／cm。强度的UVB照射二细胞期胚胎600s,100μW／cm^2强度的UVB照射20s、60s、600s,120μw／cm。强度的UVB照射20s,导致胚胎发育过程中死亡率明显升高,畸胚数量多且畸变程度高。结论：UVB照射剂量和时间不同,对中华大蟾蜍早期胚胎发育的影响有明显差异。     

DNA甲基化与脊椎动物胚胎发育

DNA甲基化是指DNA甲基转移酶(DNMT)将DNA序列中的5′胞嘧啶转变为5′甲基胞嘧啶的化学修饰, 可以调控基因的时空特异性表达, 从而影响细胞命运决定和分化等生物学过程。近年来研究发现, DNA甲基化在脊椎动物胚胎早期发育中有重要作用, Dnmt基因的缺失会影响胚胎早期发育和多个器官的形成及分化, 如胚胎早期致死、内脏器官和神经系统终末分化缺陷以及血液发生紊乱等。文章总结了DNA甲基化转移酶在小鼠和斑马鱼发育过程中的动态变化, 并系统阐述了DNA甲基化在胚胎早期发育和器官发生中的作用, 重点揭示DNA 甲基化转移酶与组蛋白甲基化转移酶如何协同调控DNA甲基化从而影响基因转录的分子机理。DNA甲基化作为一种关键的表观遗传学因素, 全面系统地理解其在胚胎发育过程中的作用机制对靶向治疗人类相关疾病有一定的理论指导意义。     

水平回转培养对斑马鱼血管发育的影响

随着空间生命科学的发展, 微重力对生命体的影响已成为科学家们日益关注的问题。多数研究表明, 微重力对生物体胚胎早期发育有着重要影响, 而血管系统作为胚胎最早行使功能的系统备受关注。目前关于微重力对血管发育影响的研究大多来自对离体培养细胞的体外回转模拟实验, 在体实验相对较少。文章利用斑马鱼作为模式动物, 在体探究水平回转培养环境下斑马鱼胚胎早期发育及水平回转培养对其血管系统发育的影响。在斑马鱼受精后24 h(24 hpf)时进行水平回转培养处理, 至36 hpf时收集胚胎, 通过体视显微镜观察斑马鱼表型变化, 通过半定量RT-PCR、qPCR及全胚原位杂交等手段对比水平回转培养环境下与对照组血管相关因子的表达情况, 并通过BrdU掺入及TUNEL法进行斑马鱼全胚细胞凋亡及增殖检测。结果表明, 在90 r/min水平回转培养环境下, 斑马鱼死亡数量没有差异, 24 hpf时破壳数量显著降低(10.3±0.41 vs. 0.0, P<0.05), 心率显著加快(223.5±2.32 vs. 185.0±3.23, P<0.05), 黑色素明显增加, 动静脉发育紊乱, 且在120 r/min转速下, 胚胎血管特异性表达因子flk1、flt4及 ephrinB2的表达均显著降低, 斑马鱼细胞凋亡明显增加, 而细胞增殖无显著差异, 提示水平回转培养对斑马鱼胚胎发育特别是早期血管发育具有重要影响。     

斑马鱼胚胎和肿瘤细胞评价细胞毒药物活性比较研究*

目的:比较斑马鱼胚胎和肿瘤细胞作为药物筛选模型的优缺点.方法:采用MTT法检测顺铂、紫杉醇、阿霉素、5-氟尿嘧啶四种药物对HL-60和Hela细胞的增殖影响;同时,观察药物对斑马鱼胚胎发育的影响.结果:阿霉素、顺铂及紫杉醇作用于HL-60及Hela细胞的IC50均显著高于作用于斑马鱼胚胎的LD50;而5-FU作用于肿瘤细胞和斑马鱼胚胎的结果与其它药物相反;四种抗肿瘤药物对斑马鱼胚胎的生长发育均有致畸作用.结论:斑马鱼胚胎作为细胞毒类药物筛选模型,对于抗微管类药物较为敏感,但对于抗代谢药敏感性较肿瘤细胞差.     

综述: DNA甲基化在动物胚胎和生殖细胞发育过程中的重编程

表观遗传信息DNA甲基化在动物的发育、细胞分化和器官形成过程中,起着至关重要的作用．近期,关于DNA甲基化在脊椎动物胚胎发育和生殖细胞发育过程重编程的研究取得了重要的进展．发现斑马鱼的早期胚胎完整地继承了精子的DNA甲基化图谱,而哺乳动物的早期胚胎和原始生殖细胞发育过程则经历了整体去甲基化并重新建立甲基化图谱的过程,但胚胎发育过程中基因的印迹区未发生DNA去甲基化,而生殖细胞发育过程中印迹区的甲基化修饰被消除．     

外源性视黄酸对斑马鱼心血管系统发育的影响

目的观察不同浓度外源性视黄酸对斑马鱼早期胚胎和心血管系统发育的影响,为进一步研究视黄酸影响斑马鱼心脏前后轴(A-P轴)发育的分子机制提供形态学依据。方法选择斑马鱼胚胎孵育的3,6,9·5,12h四个时间点,用不同浓度视黄酸(1×10-6,1×10-7,4×10-8,1×10-8mol/L)处理斑马鱼胚胎,在解剖显微镜下实时观察斑马鱼胚胎心脏发育的全过程和视黄酸对斑马鱼心脏发育的影响。并采用胚胎整体原位杂交技术观察flk-1mRNA在斑马鱼胚胎的表达。结果1×10-6mol/L视黄酸可导致斑马鱼胚胎表现出多系统的严重畸形,胚胎很快死亡。在胚胎孵育的9·5、12h给与10-7~10-8mol/L浓度的视黄酸,胚胎只表现出心血管系统的畸形,其他系统无明显异常。胚胎整体原位杂交显示视黄酸对flk-1mRNA在斑马鱼胚胎血管的表达没有影响。结论视黄酸影响斑马鱼胚胎心脏发育有剂量依赖性和严格的时间窗,视黄酸影响心脏前后轴发育的关键时间是原肠胚晚期。视黄酸处理组胚胎的循环缺陷主要为心脏发育异常所致。10-7~10-8mol/L浓度视黄酸在9·5、12h处理斑马鱼胚胎可以作为研究心脏发育调控机制的动物模型。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.