南方红豆杉悬浮培养细胞凋亡的组织学定位及与细胞分？…

应用末端脱氧核苷酸转移酶介导的ｄＵＴＰ原位切口末端标记检测技术和显微图像定量分析方法研究了悬乳培养中南方红豆杉（Ｔａｘｕｓ ｃｈｉｎｅｎｓｉｓ ｖａｒ． ｍａｉｒｅｉ）细胞团不同区域细胞凋亡的发生,并比较了不同区域的细胞形态。结果显示细胞团可以划分为三个不同的区域：核心区的细胞结构已消失,可见一些分化良好的管状结构;中层区是由增殖能力旺盛的分生组织细胞所构成;外层区是由分化成熟的细胞所组成。细胞凋     

猕猴胚胎干细胞的诱导分化和凋亡

采用单层培养法研究维生素A酸(RA)、神经生长因子(NGF)、上皮生长因子(EGF)和碱性成纤维生长因子(bFGF)对猕猴胚胎干细胞系R366．4的诱导分化和凋亡的作用。结果表明：①不添加任何生长因子的条件下,细胞分化不定向,各种细胞所占的比例表现出明显的随机性;②添加单一生长因子能促进细胞的分化进程,并使某一类或某几类的分化细胞比例上升,RA和NGF均能促进神经样细胞的形成,EGF促进内皮样细胞的形成,bFGF提高成纤维样细胞的比例;③在分化的过程中伴有细胞早期和晚期凋亡的发生,RA和NGF可增加细胞凋亡的数量。这种由生长因子诱导的动物胚胎干细胞的分化可能存在种间差异。     

屋顶长生草叶的解剖结构及其离体培养形态发生的研究

对屋顶长生草叶的解剖结构及其在离体培养条件下形态发生过程进行了研究。结果表明,屋顶长生草的叶具有肉质旱生植物叶的特点,表皮细胞外有角质层,叶有较密的腺毛分布,气孔器由两个肾形的保卫细胞和两个镰刀形的护卫细胞组成;叶肉细胞没有栅栏组织与海绵组织之分,细胞比较大,有贮水作用;维管束平行排列,导管和筛管分子都很小,为一圈维管束鞘所包围。屋顶长生草叶片离体培养形态发生途径主要有两种:一种是由外植体直接产生不定芽(器官型)途径;另一种是叶肉细胞脱分化成胚性细胞,经胚性细胞团形成愈伤组织,再分化产生芽、根等器官(器官发生型),芽分化为内起源。     

植物学彩色显微摄影系列之三--植物的组织

植物的个体发育是植物细胞 (根尖、茎尖 )不断分裂、生长和分化的结果。一般植物细胞分裂后形成的子细胞都先进行生长 ,当达到一定大小后 ,就开始有各种不同的成熟变化 (即分化 ) ,发育成各种形态不同、功能不同的细胞群或细胞组合 ,称组织 (tissue)。也就是说 ,植物组织是由形态结构相似、生理功能相同的一种或数种类型的细胞群构成的。按它的细胞发育状态可以分为分生组织和成熟组织两大类 ,前者是具有分生新细胞能力而未完全分化的幼态细胞 ,后者是在器官形成时 ,由分生组织分裂产生 ,再经过高度的分化而转化来的。按其主要功能的不同又…     

蕨类植物紫萁绒毡层细胞凋亡的细胞学特征

绒毡层凋亡过程是小孢子发生中的重要事件,以往的研究主要集中在被子植物,蕨类植物尚未见此方面的报道。该研究首次采用透射电镜和免疫荧光技术对蕨类植物紫萁(Osmunda japonica Thunb.)绒毡层细胞凋亡的细胞学过程进行了观察,以明确紫萁绒毡层细胞的发育类型和凋亡特征,为蕨类植物绒毡层细胞凋亡的深入研究以及孢子发育研究提供依据。结果显示：(1)紫萁的绒毡层属于复合型,即外层绒毡层为分泌型,该层细胞发育过程中液泡化,营养物质被吸收;内层绒毡层为原生质团型,经历了细胞凋亡的过程。(2)绒毡层内层细胞在凋亡过程中细胞壁和细胞膜降解,细胞质浓缩且空泡化;细胞核内陷、变形,染色质浓缩凝聚,形成多数小核仁,DAPI荧光由强变弱;线粒体、质体、内质网、高尔基体等细胞器逐渐退化,液泡中多包含纤维状物、絮状物、黑色嗜锇颗粒和小囊泡等;出现多泡体、多膜体和细胞质凋亡小体,上述特征与种子植物绒毡层凋亡特征基本一致。(3)与种子植物相比,紫萁绒毡层的细胞凋亡开始得早,在整个凋亡过程中没有核凋亡小体的产生;除了产生孢粉素外,绒毡层细胞内产生了大量的丝状物质、絮状物质和电子染色暗的颗粒物,这些物质可能用于...     

玉米根细胞发育过程中核孔复合物的变化(英文)

以玉米根部不同区域(分生区、伸长区和分化区)为材料,进行冷冻蚀刻,对不同生长阶段的细胞核大小、核孔复合物数量及孔径进行了测量,证明根尖细胞在整个发育周期中,细胞核膜孔总量几乎不变旭核孔复合物的孔径差异颇大。分生区核孔复合物的孔径平均约50 nm;伸长区有80％核孔直径为80 nm;分化区核孔直径恢复到50 um。这些复合物孔径的变化周期与Jordan等(1980)由玉米根部观察到三个区域的染色质变化相符,在细胞伸长区常染色质多,合成RNA旺盛,核孔复合物开大,以利RNA进入细胞质合成蛋白质。     

红盖鳞毛蕨孢子囊早期发育与质体分化的研究

利用光学显微镜和透射电子显微镜观察了红盖鳞毛蕨(Dryopteris erythrosora(Eaton)O.Ktze.)孢子囊的发育及在此期间质体的分化过程。研究表明:(1)红盖鳞毛蕨孢子囊的发育类型属于薄囊蕨型;(2)绒毡层为混合型,即内层绒毡层为原生质团型,外层绒毡层为腺质型;(3)孢子囊原始细胞中的质体通过3条路径分化,其一,原始细胞中含淀粉粒的质体通过分裂分配到下方细胞,继而进入孢子囊柄;其二,原始细胞分裂产生的新生质体被分配到上方细胞,进而被分配到除顶细胞外的原基细胞中,顶细胞将含淀粉粒的质体通过分裂分配到外套层原始细胞中;其三,顶细胞也将具淀粉粒的质体通过分裂分配到内部细胞,使分裂产生的孢原细胞和绒毡层原始细胞具新生质体;造孢细胞和孢子母细胞的质体具淀粉粒,孢子母细胞还具油体,新生孢子中具造粉体和油体;两层绒毡层具新生质体,随着退化外层绒毡层出现造粉体,内层绒毡层出现油体;(4)红盖鳞毛蕨与少数被子植物小孢子发育阶段质体分化模式类似,由前质体分化为造粉体再到油体。研究结果为蕨类植物质体在孢子囊发育过程不同组织细胞中的差异分化提供了新观察资料,为蕨类植物发育生物学和系统演化研究提供科学依据。     

海蜇胚胎发育和变态过程超微观察

采用扫描电镜、透射电镜和蛋白银染色等方法研究了海蜇胚胎发育和变态过程中细胞超微结构变化。结果显示: (1)海蜇自受精卵至原肠期阶段细胞均等分裂, 细胞间存在大量连接, 细胞形态相近, 未出现显著分化; (2)海蜇自早期浮浪游虫阶段, 其外胚层细胞开始出现空泡化, 至4触手螅状体阶段外胚层细胞空泡体积逐渐增大, 而内胚层细胞仅在4触手螅状体阶段才出现空泡化。伴随着外胚层细胞空泡化比例的增大, 杯状体和4触手螅状体阶段出现疑似凋亡小体结构; (3)刺细胞分化于早期浮浪游虫期的外胚层近中胶层区域, 而后逐渐向外转移, 至4触手螅状体阶段发育成熟并转移至表面; (4)纤毛形成于早期浮浪幼虫, 在杯状体阶段逐渐退化, 并于4触手螅状体阶段完全消失; (5)在海蜇早期发育各个阶段, 其内部均发现大量着色较深的卵黄体, 且在浮浪游虫阶段首次发现了海蜇外层细胞主动吞噬细菌现象, 表明海蜇早期发育营养来自内源性和外源性两部分。研究结果可为阐明刺胞动物早期发育模式提供依据。     

作用于微管的药物介导的细胞周期及调亡信号通路

有机体及其组织完整性的维持有赖于增殖、分化和凋亡之间平衡的精细调节,某一阶段的不完全成熟或分化失常或正常的凋亡功能丧失所造成的生长失控均会导致这种平衡的显著变化。因此,可通过激活某一通路使细胞发生周期阻滞,分化或凋亡来控制癌细胞生长。     

红盖鳞毛蕨孢子发育的超微结构和细胞化学研究

采用透射电镜和细胞化学技术对红盖鳞毛蕨(Dryopteris erythrosora(Eaton)O.Ktze.)的孢子发育过程进行了研究,根据超微结构和细胞化学特征可将其孢子发育过程分为3个阶段:(1)孢子母细胞及其减数分裂阶段:孢子母细胞壳在孢原细胞末期开始形成,位于孢子母细胞及其减数分裂形成的四分体外侧,PAS反应显示其为多糖性质,与胼胝质壁为同功结构;在减数分裂形成的四分孢子之间产生孢子外壳,从功能、形成位置和时间上看与胼胝质壁相似,但苏丹黑B反应显示其可能含有脂类物质,与孢子母细胞壳和胼胝质壁不同。(2)孢子外壁形成阶段:外壁为乌毛蕨型(Blechnoidal-type),由薄的多糖性质的外壁内层和表面平滑的孢粉素外壁外层构成;小球参与外壁外层的形成,组织化学分析显示小球的中央区域和外壁外层内侧部分由红色(多糖)变为黄色,小球的表面区域和外壁外层部分始终被染成黑色(脂类),可知小球与外壁同步发育。(3)孢子周壁形成阶段:周壁为凹陷型(Cavate-type),包括2层,内层薄,紧贴外壁,外层隆起形成孢子脊状褶皱纹饰的轮廓,以少见的向心方向发育;苏丹黑B和PAS反应观察周壁被染成橙色,推测其可能由多糖等成分构成;孢子囊壁细胞参与周壁的形成。本研究为揭示蕨类植物孢子发生的细胞学机制提供了新资料。     

Characteristics of the membranes of the pellicle of the ciliatePseudomicrothorax dubius

Summary The membranes of the pellicle of the ciliatePseudomicrothorax dubius are investigated using thin section electron microscopy and freeze-fracture replicas. The plasma membrane is covered by a surface coat and is connected to the outer alveolar membrane by short, sometimes branched, bridges. The inner alveolar membrane is coated on both sides. The epiplasm lies in intimate contact with the cytoplasmic surface of this membrane, and there is a corresponding deposit on the other surface. This deposit is regularly striated.The epiplasmic layer and the alveoli are interrupted at sites of cytotic activity,e.g., the attachment sites of trichocysts, the cytoproct, and the parasomal sacs. The striated deposit ends where the epiplasm ends, indicating a direct relationship between these two epimembranous layers.There is a deposit along the sides of the first part of the tip of the trichocysts, and in this region the trichocyst membrane is free of intramembranous particles.The membrane of the parasomal sacs has a coat on both surfaces. That on the extraplasmic surface is similar to the surface coat of the plasma membrane. The origin of the cytoplasmic coat is unknown. The cytotic activity of these sacs is indicated by their highly irregular profiles.     

The early development of the tail and the transformation of the shape of the nucleus of the spermatid of the domestic fowl,Gallus gallus

Summary The differentiation of the spermatid, especially in reference to the formation of the flagellum, and transformation of the shape of the nucleus was investigated in the domestic fowl.In the early stage of the spermatid, a prominent Golgi apparatus appears around the centrioles. The Golgi vesicles then surround the axial-filament complex which develops from the distal centriole. These vesicles fuse to form continuous membrane at the earliest stage of flagellar formation, and in the succeeding stage Golgi lamellae are attached to the plasma membrane of the developing flagellum. From these observations, it is assumed that Golgi apparatus may be a source of the membrane system of the flagellum.The microtubules distributed around the nucleus form the circular manchette. The anterior region of the nucleus with the manchette is cylindrical in shape and the posterior region without it remains irregular in shape. When the circular manchette has been completed, the whole nucleus acquires a slender cylindrical shape. The circular manchette then changes into the longitudinal manchette. The nuclei of spermatids without a longitudinal manchette are abnormal in shape. In view of these observations it is assumed that the nuclear shaping of the spermatid may be accomplished by circular manchette and the maintenance of shape of the elongated nucleus by longitudinal manchette.The authors wish to thank Mr. Takayuki Mori for his helpful suggestions and technical advices     

Characterization of the composition of the aqueous humor and the vitreous body of the eye of the frog Rana temporaria L

This study aimed to analyze the aqueous humor (AH) and the vitreous body (VB) of the eye of the adult frog Rana temporaria L. as a representative species of amphibians, which lead a semi-terrestrial life. The presence of collagen, albumin, uric acid and electron donors was shown in both media; however, there are slight differences in their concentrations. To determine collagen, a spectral-fluorescent probe, cyanine dye, was used. The presence of collagen in AH of the frog was found at the first time. The total content of electron donors (ascorbic and uric acids, tryptophan, and tyrosine) in VB and HA was roughly estimated at ~ 1.5 × 10^− 4 mol/L. Both VB and AH absorb light in similar UV regions. The total protein and albumin contents in AH were found to be somewhat higher than those in VB. The uric acid content was at an equally low level in both intraocular media. It is supposed that the similarity of VB and AH compositions shown in this work is due to some exchange between VB and AH contents in the course of accommodation. The role of intraocular fluids in physiological functions of the eye and in protecting the retina against UV light is discussed.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418