中国对虾卵子活化及卵裂的激光扫描共聚焦显微镜研究(英文)

有报导,与其它动物不同,对虾的卵子一接触海水、不经过受精,就可以被活化。但是,只有受精卵才能卵裂发育。而且,各种对虾卵子内皮质棒及皮层颗粒的形态结构、活化过程各有不同。本文就中国对虾卵子的活化及卵裂过程进行了激光扫描共聚焦显微镜（ＬＳＣＭ）研究。该技术可以清晰地显示细胞的立体图像。采集中国对虾,人工诱导产卵,未受精卵取自产卵虾体内,受精卵分期分批取样,固定。供试样品经ＰＢＳ漂洗,ＡＯ、ＦＩＴＣ和ＰＩ染色,ＬＳＣＭ观察、图像处理。刚产出的、未活化卵子形态不规则,皮层内富含皮质棒和皮层颗粒（Ｆｉｇ１）。不论受精与否,产入海水的卵子都能被激活并恢复减数分裂。活化后的卵子释放出皮层囊泡内的皮质棒（Ｆｉｇｓ２＆３）。释放出的皮质棒转变为均质的胶质层（Ｆｉｇｓ４＆５）。随后,皮层颗粒释放并在卵子表面转化为均质化的孵化膜。卵子开始举起,与孵化膜之间形成卵周隙。卵周隙内具有絮状物质（Ｆｉｇｓ６,７＆８）。卵子产出后笫８～１０ｍｉｎ,经过减数分裂,第一极体排放,并随着孵化膜的举起而被推向卵外（Ｆｉｇ５）。笫２０ｍｉｎ,第二极体排放,并由卵子表面到达孵化膜的内缘（Ｆｉｇ６）。在２０℃水温条件下,受精卵产入海水中６０     

卵母细胞减数分裂的抑制与启动的生化机理

卵子的发生,是一种在形态和物质上都极为复杂的变化过程,这个过程基本上经历了三种细胞形式——卵原细胞、卵母细胞和卵子。在卵原细胞向卵母细胞转化之时,减数分裂开始,并以排出第二极体结束。在整个减数分裂过程中,出现有两次中途停止的现象(以脊椎动     

皱纹盘鲍受精过程的电镜观察

本文用透射电镜观察了皱纹盘鲍的受精过程。鲍卵子的胶膜使精子活化,并诱发了顶体反应,卵黄膜使顶体反应达到高潮。精子入卵后,卵发生皮层反应并形成受精膜开 减数分裂。此外,还观察到鲍的多精入卵现象。     

中国对虾受精过程中精卵核的细胞学变化

中国对虾精子以其棘部顶端随机附着在卵上,精子在凝胶膜形成后,第一极体排出前入卵,精子入卵后,絮状的精核经过重建形成雄原核,中国对虾卵子排放时处于第一次成熟分裂的中期,卵子入海水时,纺锤体的长轴与质膜平行,卵子激活后,纺锤体的长轴开始旋转,旋转至纺鲑体长轴与质膜垂直时,由纺锤丝牵引着染色体向两极移动,外侧的染色体由质膜包裹形成第一极体,受膜举起后,由次级卵母细胞排放出第二极体,此后,单倍雌核重建形成雌原核,雄原核形成早于雌原核,雌雄原核于卵子中央联会形成联合核,受精后的50分钟纺锤丝牵关染色体称向两极,质膜内缢断裂形成两个细胞的胚胎。     

去甲斑蝥酸钠对小鼠卵母细胞第一次减数分裂的影响

体外培养的小鼠卵母细胞在１２ｈ内可完成第一次减数分裂,排出第一极体。将卵母细胞培养在含２５０μｇ／ｍｌ去甲斑蝥酸钠的培养液中,生发泡破裂（ＧＶＢＤ）过程不受影响,但卵母细胞不能完成减数分裂过程,卵母细胞中没有减数分裂器的形成,染色体紧密凝缩在一起;去甲斑蝥酸钠对小鼠卵母细胞减数分裂的影响在６ｈ内具有可逆性：卵母细胞ＧＶ破裂后用去甲斑蝥酸钠处理２ｈ换正常培养液培养,整个减数分裂过程不受影响;ＧＶ期卵母细胞用去甲斑蝥酸钠连续处理６ｈ,洗去药物继续培养,减数分裂可继续进行,但第一极体的排放时间推迟。去甲斑蝥酸钠对分裂期细胞特异性磷蛋白的出现影响不显著,在连续处理的卵母细胞中分裂期细胞特异性磷蛋白仍然存在。     

卵子皮层颗粒的功能

皮层颗粒是卵内一种特殊的、由膜包围的一种分泌颗粒,它位于质膜之下,许多无脊椎动物和脊椎动物单精受精卵都有此细胞器,生理多精受精卵则没有。当卵受精时发生胞吐作用,将其内含物释放,这过程被称为皮层反应。它的作用主要使卵的外膜发生变化,阻止多精受精以及保护胚胎发育,防止不利的环境条件。 1.卵子皮层卵子皮层是一位于质膜下呈凝胶的细胞质薄层,不同动物的厚度不同,1—5微米。皮层颗粒即位于此皮层中,若离心,卵内细胞质很易分层,而皮层颗粒不易被分离。因此皮层为一半固体的弹力层,其硬度主要取决于Ca~(2+)的存在。未受精卵的皮层含有单体的肌动蛋白,受精时随皮层反应肌动蛋白发生多聚作用而形成一凝胶的网状结构。从分离卵子表面的实验表明皮层颗粒牢固     

唇(鱼骨)受精卵的皮层反应及其引发机制

唇[鱼骨]皮层小泡1-4层,在光镜和透射电镜下均具5种形态,由外及内,小泡内颗粒直径逐渐减少。在H．E染色中,动物极低纬度区和精孔器附近的卵膜和质膜之间,具少量均匀的着色非常深的紫色斑点,与Ⅰ型皮层小泡内容物形态结构相似,在透射电镜下,这些斑点和卵膜、质膜有明显的界限,其外没有包被膜相结构,我们称之皮层反应引发斑,这是在鱼类受精卵中发现的一个新的结构。扫描电镜下,引发斑成絮状。引发斑对皮层反应的引发具有重要作用。皮层反应可分为潜伏期、始发期、高潮期、衰退期四个时期,潜伏期没有皮层反应发生,始发期只是位于受精卵外围的少量皮层小泡释放,高潮期为多个皮层小泡相互融合形成一个大的泡状体,泡状体再与质膜接触、融合后,随后破裂,释放内容物,可分为两个阶段,衰退期释放Ⅴ型皮层小泡和其他残存的皮层小泡以及未完全降解卵黄颗粒碎屑;皮层反应是由Ⅰ型皮层小泡和引发斑诱导的爆发性的链式反应,卵子外侧的皮层反应可以诱导内侧皮层反应。皮层反应有两个起始区域,在受精后35s开始于动物极低纬度区,稍后出现在精孔器前庭附近,随后在这两个始发区向四周扩散,并在前庭以外的区域愈合、打通。皮层小泡分批多次释放,质膜多次重组。精子人卵位点附近没有皮层小泡,不发生皮层反应,这提示皮层反应对鱼类多精受精的抑制效应有限。     

唇受精卵的皮层反应及其引发机制

唇皮层小泡1-4层,在光镜和透射电镜下均具5种形态,由外及内,小泡内颗粒直径逐渐减少。在H．E染 色中,动物极低纬度区和精孔器附近的卵膜和质膜之间,具少量均匀的着色非常深的紫色斑点,与Ⅰ型皮层小泡内 容物形态结构相似,在透射电镜下,这些斑点和卵膜、质膜有明显的界限,其外没有包被膜相结构,我们称之皮层反 应引发斑,这是在鱼类受精卵中发现的一个新的结构。扫描电镜下,引发斑成絮状。引发斑对皮层反应的引发具 有重要作用。皮层反应可分为潜伏期、始发期、高潮期、衰退期四个时期,潜伏期没有皮层反应发生,始发期只是位 于受精卵外围的少量皮层小泡释放,高潮期为多个皮层小泡相互融合形成一个大的泡状体,泡状体再与质膜接触、 融合后,随后破裂,释放内容物,可分为两个阶段,衰退期释放Ⅴ型皮层小泡和其他残存的皮层小泡以及未完全降 解卵黄颗粒碎屑;皮层反应是由Ⅰ型皮层小泡和引发斑诱导的爆发性的链式反应,卵子外侧的皮层反应可以诱导 内侧皮层反应。皮层反应有两个起始区域,在受精后35s开始于动物极低纬度区,稍后出现在精孔器前庭附近,随 后在这两个始发区向四周扩散,并在前庭以外的区域愈合、打通。皮层小泡分批多次释放,质膜多次重组。精子入 卵位点附近没有皮层小泡,不发生皮层反应,这提示皮层反应对鱼类多精受精的抑制效应有限。     

唇受精卵的皮层反应及其引发机制

唇(鱼骨)皮层小泡1-4层,在光镜和透射电镜下均具5种形态,由外及内,小泡内颗粒直径逐渐减少.在H.E染色中,动物极低纬度区和精孔器附近的卵膜和质膜之间,具少量均匀的着色非常深的紫色斑点,与Ⅰ型皮层小泡内容物形态结构相似,在透射电镜下,这些斑点和卵膜、质膜有明显的界限,其外没有包被膜相结构,我们称之皮层反应引发斑,这是在鱼类受精卵中发现的一个新的结构.扫描电镜下,引发斑成絮状.引发斑对皮层反应的引发具有重要作用.皮层反应可分为潜伏期、始发期、高潮期、衰退期四个时期,潜伏期没有皮层反应发生,始发期只是位于受精卵外围的少量皮层小泡释放,高潮期为多个皮层小泡相互融合形成一个大的泡状体,泡状体再与质膜接触、融合后,随后破裂,释放内容物,可分为两个阶段,衰退期释放Ⅴ型皮层小泡和其他残存的皮层小泡以及未完全降解卵黄颗粒碎屑;皮层反应是由Ⅰ型皮层小泡和引发斑诱导的爆发性的链式反应,卵子外侧的皮层反应可以诱导内侧皮层反应.皮层反应有两个起始区域,在受精后35s开始于动物极低纬度区,稍后出现在精孔器前庭附近,随后在这两个始发区向四周扩散,并在前庭以外的区域愈合、打通.皮层小泡分批多次释放,质膜多次重组.精子入卵位点附近没有皮层小泡,不发生皮层反应,这提示皮层反应对鱼类多精受精的抑制效应有限.     

厦门港球型侧腕水母(Pleurobrachia globosa Moser)的生殖

球型侧腕水母是厦门港最常见、数量最大的栉水母。雌雄同体。主要生殖季节在4—7月,是水产养殖业的重要敌害。精、卵多在下半夜排放。精子和卵子分别由位于两栉毛板之间的输精孔和输卵孔排出。卵子呈圆球状,其外为一层透明的胶质卵膜。平均卵径为319.2±57.5μm。胚胎发育在胶质膜内进行。当膜内幼体的雏形平衡囊、栉毛带、口及口道形成之后,幼体便用口及口道顶破胶质膜而孵出。     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV