中国对虾精子顶体反应的超微结构和蛋白成分变化的研究

用卵水（egg water)对中国对虾纳精囊内精子进行人工诱导顶体反应,并分别用透射电镜和SDS－PAGE及复性单向电泳对顶体反应的超微结构变化和蛋白成分的变化进行了研究。结果表明,中国对虾精子在人工诱导条件下30min内有50％以上完成反应。电镜观察证明,中国对虾精子的顶体反应可分为两个阶段;（1）棘突的收缩;（2）顶体颗粒的释放和顶体帽的消失。在反应过程中许多蛋白被降解,且反应开始后精子本身释放出一些水解酶类,主要有200kDa、130kDa、66kDa、53kDa、48kDa和41kDa 6种。在对卵水成分的初步分析中发现两种分子量约200kDa的蛋白。     

三疣梭子蟹精子顶体反应过程中的形态和结构变化

用离子载体A2 3187和卵水人工诱导三疣梭子蟹精子的顶体反应 ,分别获得 75 33%和 84 83%的顶体反应率。应用光镜和电镜技术观察了顶体反应前后精子形态和结构的变化。未处理精子呈陀螺形 ,由顶体、核杯和 5 - 10条核辐射臂组成。顶体包括顶体囊和顶体管。顶体囊的伞形头帽拥有约 70条辐射肋。连续发生的精子顶体反应过程被人为地分为四个阶段 :(1)头帽鼓起 ;(2 )顶体囊外翻 ;(3)穿孔器前伸 ,顶体囊膜翻转 ;(4 )顶体囊膜脱落 ,顶体丝形成。直到第四阶段才观察到钉状精子的辐射臂开始收缩。探讨了辐射臂和穿孔器前冲在精子入卵中的功能     

中华绒螯蟹(Eriocheir sinensis)精子顶体反应的研究

分别用卵水、海水、caCl_2或NaCl水溶液对中华绒螯蟹成熟精子进行人工诱导顶体反应,结果表明:精子的生理性成熟、同种卵或Ca~(++)的存在、碱性环境以及与一定的固体接触均为精子顶体反应触发的重要条件。3月份精子诱导率最高。 电镜观察证明,中华绒螯蟹精子的顶体反应可分四个阶段:(1)辐射臂收缩;(2)顶体囊外翻;(3)顶体管前伸;(4)片层结构脱落。     

TELEOGRYLUS EMMA精子体外顶体反应的超微结构比较研究

采用相同种类卵水诱导的方法对直翅目,蟋蟀科,黄脸油葫芦的受精囊精子的顶体反应过程进行系统观察.发现黄脸油葫芦精子顶体反应可划分为3个阶段,第1阶段,精子质膜膨胀、断裂或丢失;第2阶段,顶体复合体的顶体外层与顶体本体外膜发生融合,囊泡化;第3阶段,顶体复合体大部分脱落,只留有短锥状的顶体位于核前端.据观察,蟋蟀精子质膜不参与囊泡形成,此结果与家蝇及哺乳类的猪、牛、绵羊、猕猴精子的顶体反应结果很相似.经过比较发现卵水对受精囊内精子的诱导率明显高于精巢内,据分析,可能与精子的生理成熟有关,即便受精囊内精子比精巢内精子更趋于成熟.与其他学者的实验结果相比,蟋蟀精子顶体反应率与家蝇的相似,但明显低于其他动物.这可能与动物的授精方式有关.     

SNARE蛋白及其相关蛋白在精子顶体反应中的作用

精子顶体反应是指精子顶体外膜与精子质膜发生细胞内多点融合的反应,其过程属于特殊的胞吐过程。精子顶体反应是一个复杂严谨的生理过程,不仅需要诱导剂的诱导,还需要多种相关膜融合蛋白的参与。SNARE蛋白及其相关蛋白能够调控哺乳动物细胞内的融合,尤其在精子顶体反应过程中发挥着重要作用。其中SNARE蛋白是核心成分,与其相关蛋白相互作用,共同参与精子顶体反应过程。现主要对SNAREs、Rab、Munc-18、complexin、synaptotagmin和α-SNAP等蛋白质在精子顶体反应中的作用进行概述。     

锯缘青蟹精子顶体反应的研究

采用正交实验法研究了诱导锯缘青蟹精子产生顶体反应的最佳条件。结果表明：从纳精囊中获得的精子,用离子载体Ａ23187(64μg/ml）诱导,在ＣaCl2浓度为0.25％,pH为9.0的人工海水中４０分钟,可以得到最大的顶体反应率（82.5%）。在此基础上采用光镜和电镜观察顶体反应过程中显微和超微结构的变化。顶体反应过程可大致分为两个时相,第一时相为顶体囊外翻;第二时相为顶体管前伸。本文还对顶体反应的作用进行了初步探讨。     

抗精子单克隆抗体6B10的免疫定位及其相应抗原分析

利用杂交瘤技术制备小鼠抗精子单克隆抗体 6B1 0 ,为IgG型免疫球蛋白 .通过 (NH4) 2 SO4盐析并结合蛋白A SepharoseCL 4B亲和层析法纯化单克隆抗体6B1 0 ,用SDS 聚丙烯酰胺凝胶电泳分析抗体纯度 .采用金霉素荧光染色法 (CTC)检测精子顶体反应 ,发现单克隆抗体 6B1 0可以显著地抑制孕酮诱导的精子顶体反应 .采用间接免疫荧光法和胶体金免疫电镜观察发现单克隆抗体 6B1 0的相应抗原定位于精子顶体质膜上 .用 1 %TritonX -1 0 0抽提精子全蛋白 ,采用SDS 聚丙烯酰胺凝胶电泳结合免疫印迹实验 (Westernblot)发现单克隆抗体 6B1 0所识别的抗原为 5 0ku的蛋白 ,此蛋白为精子顶体反应发生过程中的关键蛋白之一 ,可能成为免疫灭鼠与免疫避孕的候选疫苗     

哺乳动物精子中的ZP3结合蛋白研究进展

哺乳动物卵透明带糖蛋白ZP3(zona pellucida3)是介导精卵初级结合、诱发精子发生顶体反应的关键分子。目前已在精子中发现多种ZP3结合蛋白。95kD酪氨酸激酶受体可能通过其酪氨酸激酶活性介导ZP3诱发的顶体反应。β—1,4—半乳糖基转移酶与ZP3的糖基结合后,通过激活下游信号分子诱发顶体反应。精子蛋白sp56可能介导了顶体反应期间顶体基质与ZP之间的相互作用。透明带粘附素(zonadhesin)也是在顶体反应发生之后才与ZP发生相互作用。这些精子蛋白介导的下游信号事件将是下一步研究的热点。     

三疣梭子蟹精子顶体反应前后胞内Ca~(2+)的变化

应用激光扫描共聚焦显微镜(LSCM)和Fluo-3/AM荧染技术对三疣梭子蟹精子顶体反应前后的胞内Ca2 变化进行了观察和检测.结果显示,在精子顶体反应过程中,胞内Ca2 主要分布在细胞核、穿孔器和胞质膜残存处,胞内Ca2 浓度([Ca2 ]I)总体上呈现先上升后下降的趋势.顶体反应前精子的平均荧光强度为35.95±5.71;穿孔器前伸、顶体囊膜翻转阶段精子的平均荧光强度为66.80±7.35;顶体囊膜脱落、顶体丝形成阶段精子的平均荧光强度为3.87±2.82;上述各阶段间精子荧光强度有极显著差异(P<0.01).顶体反应穿孔器前伸、顶体囊膜翻转阶段的精子相比顶体反应前精子,[Ca2 ]I显著提高;而在顶体囊膜脱落、顶体丝形成阶段,[Ca2 ]I则急剧下降,只在顶体丝基部胞质膜残存处有微量Ca2 存在.初步探讨了三疣梭子蟹精子顶体反应前后胞内Ca2 变化的功能.     

与顶体反应相关的抗人精子单克隆抗体及其抗原的特性 Ⅱ单克隆抗体对精子功能的影响以及抗原定位与免疫印迹

精子只有经过获能和顶体反应,才能与卵融合。本文对以体外诱导的顶体反应人精子作为免疫原制备的23个单克隆抗体进行了一系列鉴定,结果表明:所得单克隆抗体的间接免疫荧光染色,主要定位在人精子的赤道板和中段,没有发现定位于顶体及顶体后的单克隆抗体。某些单克隆抗体的间接免疫荧光染色部位在顶体反应后发生了改变。有18个单克隆抗体显示程度不同的精子凝集作用,未发现有精子制动作用的单克隆抗体。免疫印迹证实,有9个单克隆抗体的靶抗原是蛋白质类物质。     

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