线粒体融合/分裂对线粒体的质量控制作用

线粒体是一种结构和功能复杂而敏感的细胞器,拥有独立于细胞核的基因组,在细胞的不同时相,生理过程和环境条件下,线粒体的形态,数量和质量,具有高度的可塑性。线粒体是细胞和生物体内最主要的能量供应场所,几乎存在于所有种类的细胞中,是一种动态变化的细胞器。正常情况下,线粒体的数量、形态以及功能维持相对稳定的状态,称之为线粒体稳态。当上述状态发生紊乱时,细胞乃至生物体形态、功能也将受到影响甚至死亡。线粒体质量控制是在细胞中维持正常状态的关键机制,决定着线粒体的命运。近年,随着线粒体研究的深入和具体,逐渐发现融合/分裂在其形态、数量、遗传物质等质量控制相关的方面挥了重要作用。本文通过探讨融合/分裂对线粒体质量控制的作用机制,总结和讨论相关前沿研究,为后期研究提供一定的理论依据。     

奶山羊不同发育时期乳腺上皮细胞中内质网和线粒体的变化

为研究奶山羊乳腺的胚后形态发育,采用活细胞荧光标记法结合激光共聚焦显微技术,观察奶山羊乳腺发育中内质网和线粒体的变化.结果显示:腺上皮细胞内质网和线粒体在妊娠初期和中期数量较少,妊娠晚期开始逐步增加,泌乳中期达到高峰并维持在一个较高的水平上,退化期迅速下降,逐渐恢复到妊娠前状态;退化期乳腺上皮细胞内仍保持一定数量的细胞器,以维持细胞的正常机能和活动.     

天竺葵质体和线粒体双亲遗传的细胞学机理——雄性和雌性配子超微结构和DNA荧光的研究

天竺葵（Ｐｅｌａｒｇｏｎｉｕｍ ｈｏｒｔｏｒｕｍ Ｂａｉｌｅｙ）生殖细胞和精细胞在发育中始终存在质体和线粒体。在精细胞中,质体的体积大、数量多,具基质浓厚和在切面上多为环状的特点。线粒体在生殖细胞和精细胞中没有差异,体积较质体小得多,球形或杆状,边缘染色较深。在卵细胞中质体的含量比线粒体丰富,这两种细胞器的结构形态与精细胞的有明显的差异。细胞的质体多呈不规则的棒状和含淀粉粒。线粒体比精细胞的大２—３ 倍,许多为环状。ＤＮＡ 荧光的检测证明了在生殖细胞、精细胞和卵细胞中存在质体和线粒体类核。卵中的环状线粒体类核的形态在精细胞中是不存在的。本研究确定了雄性和雌性配子的质体和线粒体在结构形态上各具特点,可作为鉴别它们的标记,从合子中查明雄性质体和线粒体是否传递,以及在胚胎发育的早期雌雄亲本来源的细胞器的动态     

小麦小孢子发生过程的超微结构

采用透镜电镜技术对小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ）小孢子发生过程进行了超微结构观察。造孢细胞时期细胞质中含有丰富的核糖体,质体和线粒体。在小孢子母细胞减数分裂过程中,有核糖体数量存在逐渐减少的现象,质体和线袜体结构在双线期／终变期和中期１简化,二分体时期,质体和线粒体形态结构基本恢复正常。结果表明,啵麦小孢子母细胞减数分裂过程中存在质体和线粒体的脱人化与再分化过程,但该过程与核糖体数量增     

天竺葵质体和线粒体双亲遗传的细胞学机理——雄性和雌性配子微结构…

天竺葵生殖细胞和精细胞在发育中,始终存在质体和线粒体。在精细胞中,质体的体积大、数量多、具基质浓厚和切面上多为呈现的特点。线粒体在生殖细胞和精细胞中没有差异,体积较质体小得多,球形或杆状,边缘染色较深。在卵细胞中质体的含量比线粒体丰富,这两种细胞器的结构形态与精细胞的有明显的差异。细胞的质体多呈不规则的棒状和含淀粉粒。线粒体比精细胞的大２－３倍,许多为环状。ＤＮＡ荧光的检测证明了在生殖细胞、精细胞     

胸腺细胞和细胞器水平的线粒体膜电势研究

以地塞米松(DEX)诱导小鼠胸腺细胞凋亡;利用PI和AnneXin V/PI流式细胞术分别检测细胞晚期和早期凋亡;利用JC-1和DiOC_6(3)/PI在细胞水平检测凋亡中线粒体膜电势(△ψm)变化：抽提线粒体,利用JC-1直接染色技术检测现存线粒体△ψm情况。实验结果显示,DEX显著诱导胸腺细胞早期和晚期凋亡,凋亡细胞主要来自G_0/G_1期;细胞水平可见DEX介导与△ψm相关的J-aggregate和DiOC_6(3)可染性降低,同时介导线粒体数量显著降低,6h细胞膜完整性无显著变化：单纯线粒体检测结果显示,多数线粒体维持正常△ψm。提示,DEX介导胸腺细胞凋亡中线粒体数量降低,现存线粒体多保持着正常△ψm以维持凋亡过程细胞能量供给。     

不同组织细胞线粒体数量及功能的休克敏感性研究

摘要 目的：探究不同组织细胞线粒体数量及功能的休克敏感性差异。方法：在整体和细胞水平模拟失血性休克和脓毒性休克模型,通过mtDNA检测、线粒体形态分析和线粒体ROS检测观察休克不同时相点肠组织（肠上皮细胞）、血管组织（血管平滑肌细胞）和心肌组织（心肌细胞）中线粒体数量和功能的变化。结果：对于失血性休克（缺氧）刺激,肠组织线粒体数量的休克敏感性明显强于血管和心肌组织（P<0.05）。肠、血管、心肌组织中线粒体数量明显增多分别开始于失血性休克后0.5小时、1小时和2小时。对于脓毒性休克（LPS）刺激,肠组织线粒体数量的休克敏感性明显弱于血管和心肌组织（P<0.05）。肠、血管、心肌组织中线粒体数量明显增多分别开始于脓毒性休克后9小时、6小时和3小时。只有高浓度长时间LPS刺激才会引起肠上皮细胞线粒体数量的明显增高。各组织细胞线粒体功能对各型休克刺激的敏感性和反应程度虽然存在差异,但都晚于线粒体数量异常的发生（P<0.05）。结论：各型休克的组织器官敏感性差异可能与不同组织细胞中线粒体的休克敏感性不同有关。线粒体数量异常增加是引起休克后线粒体损伤和细胞功能障碍的始动环节,不同组织细胞线粒体的休克敏感性差异也是影响休克组织器官损伤差异的重要原因之一。     

棉花小孢子发生过程中细胞质的超微结构变化：着重“细胞质改组”问题

棉花(Gossypium hirsutum L.)小孢子发生过程中,细胞质超微结构发生显著而有规律的变化。这些变化主要涉及细胞质中核糖体、质体和线粒体。减数分裂前期Ⅰ,细胞质中核糖体密度逐渐降低,质体和线粒体结构变得不明显。粗线期至双线期,细胞质中核糖体密度降至极低水平,同时质体和线粒体呈衰退结构状态。中期Ⅰ,细胞质中核糖体恢复致密,质体和线粒体也恢复了正常的形态和结构。来自细胞核的类核仁进入细胞质并扩散。这是恢复中期Ⅰ细胞质中核糖体密度的主要原因。内质网在核糖体数量变化中显示出有重要作用。这些细胞质超微结构的变化可认为与世代转变有关。     

四逆散对人肝癌HepG2细胞增殖、凋亡的影响及其机制*

目的: 探讨含四逆散药液血清对人肝癌HepG2细胞增殖、凋亡的影响及机制。方法: 将人肝癌HepG2细胞分为5组,每组3个复孔。实验组细胞用五氟尿嘧啶(5-FU)或不同浓度的含四逆散药液血清处理48 h后,用倒置显微镜观察含四逆散药液血清处理后人肝癌HepG2细胞形态的变化;MTT法检测含四逆散药液血清对HepG2细胞生长的抑制作用;荧光染色和流式细胞术分别分析含四逆散药液血清对HepG2细胞凋亡的影响。Rho123染色法检测线粒体膜电位变化,Western blot检测细胞凋亡相关蛋白的表达。结果: 与对照组比较,含四逆散药液血清处理人肝癌HepG2细胞后,细胞数量显著减少(P＜0.01),形态发生改变,呈现典型的凋亡细胞形态;G1期细胞数明显增加,而G2 期细胞数量显著减少(P＜0.05);Bax、Caspase-3、-9和Cyt-c的表达显著升高,而Bcl-2的表达显著降低(P＜0.05);随着含四逆散药液血清浓度增大,HepG2细胞线粒体膜电位显著下降(P＜0.05)。结论: 四逆散可以抑制HepG2细胞增殖,并通过线粒体途径诱导细胞凋亡。     

线粒体自噬调控机制研究进展

线粒体为细胞正常生命运动提供能量和物质;然而各种因素会导致线粒体损伤,衰老及功能紊乱,它们是细胞潜在的危险因素,必需及时清除,线粒体自噬可以起到这一作用,维持细胞稳态。当细胞处于恶劣环境时,线粒体自噬可通过降解线粒体补充生命必需物质,从而度过危机维持生存。另外线粒体自噬会在某些情况下通过降解正常线粒体来维持线粒体质量和数量的平衡。不同生物中具有不同的线粒体自噬途径和机制,酵母中主要通过Atg32磷酸化调控线粒体自噬;哺乳动物中则存在分别由Parkin-PINK1、Nix、FUNDC1等不同蛋白介导的线粒体自噬调控机制;植物线粒体自噬的研究主要集中在拟南芥,其途径及具体调控机制尚不明确。综述了近年来酵母、动物和植物中线粒体自噬的作用机制及调控因子等方面的研究进展。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.