中国陕西省新异蚖属一新种记述(原尾纲,古蚖目,古蚖科)

记述了采自陕西省翠华山的新异蚖属1新种,即陕新异蚖Neanisentomonshaanicum sp.nov.。新种主要特征为:前足跗节感器b′-1和c′缺失,感器d极长大;腹部第Ⅴ～Ⅵ节背板缺少前排刚毛A3,毛序为8/16,第Ⅶ节背板缺少前排刚毛A1和A3,毛序为6/16;雌性外生殖器具有明显的鸭头状的头片。该新种可以通过前足跗节感器d的长度和雌性外生殖器等特征与已知种类区分。文中同时列出了新异蚖属的世界种类检索表。     

东方扁虾精子发生的超微结构

应用电镜技术研究了东方扁虾（Thenus orientalis)精子发生的全过程,精原细胞呈椭圆形,其染色质分布较均匀,线粒体集中于细胞一端形成“线粒体区”。初级精母细胞较大,染色质凝聚成块,次级精母细胞核质间常出现大的囊泡,胞质内囊泡丰富而线粒体数量却明显减少,早期精细胞核发生极化、解聚,部分胞质被抛弃。中期精细胞外观呈金字塔形,分为三区;正在形成的顶体位于塔顶,核位于塔基部,居间的细胞质基质内富含膜复合物,后期精细胞顶体进一步分化。形成顶体帽和内、外顶体物质等三个结构组份。成熟精子核呈盘状或碗状,具有5-6条内部充满微管的辐射臂。     

无蹼壁虎精子头部形成的研究

本文用透射电镜观察了无蹼壁虎精子头形成的过程。早期精细胞具有显著的高尔基复合体、线粒体集合及细胞质桥、接着高尔基体成熟面分泌出前顶体囊泡,并逐渐向核移动。以后精子形成可分四个时间：时间Ⅰ,当前顶体囊泡移至核膜时,核膜凹陷形成封闭的顶体囊泡,囊泡底部靠近核膜有一电子致密的顶体颗粒;时间Ⅱ,细胞核延长,顶体囊泡变扁平;时期Ⅲ,细胞核进一步延长,核内染色质纤维变粗并沿核纵轴方向排列有序;时间Ⅳ,精子发育     

隆线溞精子发生及成熟精子的超微结构

用透射电镜和扫描电镜观察隆线精子的发生过程及成熟精子的超微结构。隆线精子发生经历精原细胞、精母细胞、精子细胞和成熟精子四个时期。精原细胞核染色质凝集成团,细胞质内有线粒体、粗面内质网分布。精母细胞核染色质分散,不均匀地分布于核中,细胞质内粗面内质网聚集。在精子细胞分化形成精子的早期,细胞纵向拉伸,核物质开始浓缩;中期精子细胞呈明显的长条形,精子细胞逐渐移入精巢管腔中央,外围包裹一厚层精子鞘;后期精子细胞已进入管腔中,核物质呈高度浓缩状,细胞质层较少,精子细胞间通过外围精子鞘相互粘连成片。成熟精子分散在精巢管腔中央,外形呈棒状,一端稍钝,一端稍尖,无鞭毛、棘突等附属物;核内染色质解聚,均匀分布在核中,具双层核膜,细胞质层很少,精子鞘为单层,无法确认顶体端。隆线雄性生殖细胞的结构及其发生过程均较高等甲壳动物简单和原始,但在功能上表现出相对的适应性,使以隆线为代表的枝角类能适应复杂多变的生活环境     

诸葛菜去膜精子在爪蟾卵提取物中实现非细胞体系核重建

动物爪蟾(Xenopus laevis)卵提取物诱导植物诸葛菜(Orychophragmus violaceus)去膜精子实现非细胞体系核重建. 诸葛菜去膜精子在爪蟾卵提取物中温育30 min左右开始膨大, 随着温育时间的延长, 膨大的精子染色质逐渐去凝集. 电子显微镜观察和荧光显微镜观察均表明重建核有核膜的装配, 膜泡在去凝集的染色质周围逐渐融合形成双层核膜. 用细胞分级抽提整装电子显微镜技术观察到重建核中有核纤层和核骨架结构的装配.     

半滑舌鳎精子发生和精子形成的超微结构

用电子显微镜对半滑舌鳎(Cynoglossus semilaevis)精子发生的过程及精子的超微结构进行了观察。半滑舌鳎精巢属于小叶型,精小叶由各期生精细胞和支持细胞构成。半滑舌鳎的精子发生经历了初级精原细胞、次级精原细胞、初级精母细胞、次级精母细胞和精子细胞,再经过精子形成过程发育成为精子。初级精母细胞成熟分裂的前期Ⅰ,同源染色体经历了联会复合体形成和解聚的变化。在精子形成的过程中,精细胞大致经历了核质浓缩、线粒体迁移及鞭毛的发生等过程。核质浓缩时,精细胞核内位于植入窝周围的染色质首先由细颗粒状浓缩成粗大颗粒状,然后细胞核其他部位的染色质也逐渐浓缩成粗大颗粒状。这些已浓缩成粗大颗粒状的染色质再进一步浓缩为电子密度高的均匀状物质。随着核质的浓缩,核外膜与核内膜之间的间隙增大形成核膜间隙,核内一些没有参与染色质浓缩的物质通过出芽形成囊泡,先排入核膜间隙,然后再外排到细胞质中。核浓缩过程中细胞核的体积和表面积都大大缩小;鞭毛的形成与细胞核的浓缩是同步进行的,当一对中心粒移近细胞核时,核膜凹陷形成植入窝,其周围染色质浓缩的同时,远端中心粒(基体)逐渐向后产生轴丝。成熟精子无顶体,头细长,主要为核占据,核凹窝发达,线粒体4-5个环绕在鞭毛基部形成袖套,尾细长,具侧鳍,尾部轴丝为"9 2"结构。     

菲律宾蛤仔的精子发生和精子超微结构

用透射电镜研究了菲律宾蛤仔(Ruditapes philippinarum)精子结构和精子发生过程中细胞形态结构的变化及细胞器的演变规律。菲律宾蛤仔雄性生殖细胞的形态由椭圆形渐变为辣椒状,细胞核的形态由椭圆形逐渐拉长,渐变为锥形。染色质的凝集经历：小颗粒团块状一较大颗粒均匀状一粗颗粒均匀状的过程。线粒体在演化过程中数量先增多后逐渐减少,嵴数逐渐增多,电子密度和体积逐渐增大。高尔基体在初级精母细胞期已经发育,随后的各期中发育良好,分泌旺盛。精细胞Ⅱ期,高尔基体分泌的潴泡开始融合,形成前顶体囊。精细胞Ⅲ期,高尔基体的分泌物仍不断融合。精细胞分化的后期,前顶体囊逐渐发育形成顶体。菲律宾蛤仔成熟精子呈长辣椒状,为原生型,由头部、中段和尾部构成。头部的顶体为细长柱形,末端渐细,电子密度较小;细胞核为锥形;中段线粒体4个,尾部鞭毛为典型的“9 2”型结构。此外在成熟精子线粒体环横切面有一特殊“风车状”结构。     

中国石龙子精子形成的超微结构研究

采用透射电镜观察中国石龙子精子的形成过程。结果表明:早期精细胞中有高尔基复合体和线粒体集合,由高尔基复合体所分泌的前顶体囊泡,逐渐向核移动,以后的过程可分为四个时期。时期Ⅰ:前顶体囊泡移至核膜时,核膜凹陷形成封闭的顶体囊泡,囊泡底部靠近核膜处有一电子致密的顶体颗粒,近端中心粒及鞭毛开始出现。时期Ⅱ:顶体囊泡变扁平,细胞核延长,染色质浓缩成短丝状的染色质纤维。时期Ⅲ:核进一步延长,染色质纤维变粗变长,按核纵向排列有序。时期Ⅳ:染色质纤维浓缩至最大限度,电子透明的核质消失,核呈高电子致密,顶体复合体发育完全。     

褶纹冠蚌精子发生的研究

光镜和透射电镜研究结果表明：褶纹冠蚌精子发生是非同步的,精子发生经历了一系列重要的形态和结构变化,主要包括：核逐步延长、染色质浓缩、线粒体逐渐发达与融合、胞质消除以及鞭毛的形成。精原细胞胞质中含有许多致密的轴纤丝,它们后来形成鞭毛轴丝。精母细胞质中含有线粒体、中心粒、内质网和电子透明的囊泡。精细胞分化为４个时期。成熟精子属原始类型,由头部、中段和尾部三部分组成。多核结构和细胞间桥自始至终存在于精子     

两种蝇类精细胞发育过程中细胞核的变态

本文用透射电子显微镜研究了大头金蝇(hrysomyia megacephala)和肥须亚麻蝇(Parasarcophaga crassipalpis)精细胞发育过程中细胞核的变态过程.精细胞从球形细胞演变为线形精子,核要经历四个时期,即:球核期,细胞为球形,核亦为球形,核膜与一般体细胞核无异;棒核期,核拉长如棒,顶体形成,核膜孔聚集于一侧;染色质凝聚期,染色质与核质分开,经过一系列变化,再凝聚成致密的块状,多余核质从核孔聚集处开口排出核外;成熟期,核变成一团电子密度极大的腊肠形.精细胞抛弃绝大部分细胞质和多余的结构,变成线形精子.以上演变过程两种蝇类完全相似,但在染色质凝聚期的变化中差异却很大:大头金蝇凝聚程序为:细纤维—粗纤维—块状—致密团;肥须亚麻蝇则为:蚁蚕状—纵列薄片状—厚片状—块伙—致密团.     

STUDIES OF SPERMIOGENESIS IN A NEMATODE, NIPPOSTRONGYLUS BRASILIENSIS

The fine structure of the developing spermatids and the mature sperm of Nippostrongylus brasiliensis was investigated. Immature spermatids are found at one end of the tubelike testis, and the mature sperm at the other. The spermatid has a prominent nucleus, with the chromatin clumped at the margin. It also contains a pair of centrioles, located near the nucleus. The cytoplasm is filled with ribosomal clusters, but it lacks an organized Golgi area or endoplasmic reticulum. Besides the normal mitochondria, the spermatid has specialized mitochondrionlike inclusions with dense matrix, few broad cristae, and a crystalloid structure always facing the nucleus. As spermiogenesis proceeds, the nucleus elongates, comes to lie at one end, and later evaginates to form a separate head structure, leaving the mitochondria and other cytoplasmic organelles in a broad cytoplasmic region. The nuclear material becomes filamentous and spiral, and the centrioles come to lie at one end near the junction of the head and the cytoplasmic portion of the sperm. Microtubules are found in the cytoplasmic region extending from the tubelike nucleus. The specialized mitochondria are about eighteen in number, and are arranged in rows in staggered groups of three around the microtubules in the cytoplasmic region. The mature sperm is aflagellate and lacks an acrosome. No movement of the sperm was ever observed.     

Spermiogenesis in the Hagfish Eptatretus burgeri (Agnatha)

The fine structure of spermatid differentiation in a primitive vertebrate, the hagfish, whose spermatozoa bear acrosomes, was investigated. In early round spermatids, the acrosomal vesicles were spherical and located in a shallow nuclear indentation, flanked by the plasma and the nuclear membranes. The vesicle underwent a transition through lens-shaped and cap-shaped stages until it attained the shape of a bell in mature spermatozoa. Electron-dense acrosomal material that appeared as deposits in three portions of the vesicle finally joined in the center region at a late stage. Condensation of chromatin occurred in the anterior region of the nucleus. During transformation of the spermatids, many regularly spaced microtubules appeared beneath the plasma membrane except in the anteriormost region of the cell. The microtubules in a single alignment lay parallel to one another and encased the nucleus diagonally. During an early stage, the centrioles changed their orientation from perpendicular to longitudinal and rotated to become parallel to the long axis of the nucleus. Thus, the flagellum lay nearly straight along the cell axis. A cytoplasmic canal appeared transiently during the early stage. A droplet of cytoplasm was eliminated after descending along the flagella. The features of spermiogenesis in hagfish, which lies between invertebrates and vertebrates, are compared with those of other animals.     

Spermatogenesis in a Free-Living Marine Nematode Neochromadora poecilosoma (Chromadorida,Chromadoridae) Studied Using TEM

Spermatogenesis and the structure of mature spermatozoa were studied using TEM in a free-living marine chromadorid nematode Neochromadora poecilosoma from the Sea of Japan. In spermatocytes, fibrous bodies (FB) develop; in spermatids, the synthetic apparatus lies in the residual body, while the nucleus, mitochondria, and FB are located in the main cell body (MCB). The nucleus consists of a diffuse chromatin of fibrous structure, which is not enclosed in a nuclear envelope. In the spermatid stage, the development of FB is completed, and immature spermatozoa from the proximal region of the testis do not show any structural differences from the MCB of spermatids. The mature spermatozoa are polarized cells. They attach to the uterus wall by a pseudopod filled with filaments of the cytoskeleton; in the MCB of spermatozoon, there is a nucleus surrounded by mitochondria and osmiophilic bodies. The spermatozoa of N. poecilosoma show typical ultrastructure features of sperm cells found in most studied nematodes (amoeboid nature and the absence of axoneme, acrosome, and nuclear envelope). However, no aberrant organelles characteristic of nematode spermatozoa were found throughout sperm development in N. poecilosoma and other chromadorids.     

SPERMIOGENESIS IN THE PULMONATE SNAIL, EUHADRA HICKONIS II. STRUCTURAL CHANGES OF THE NUCLEUS

In accordance with the characteristic shape of the nucleus and degree of condensation of the nuclear substance, spermiogenesis in Euhadra hickonis can be roughly divided into four stages. The chromatin in the highly polymorphic nucleus of the first stage, early spermatid, forms relatively thick (ca. 50 nm) fibrils which associate here and there into irregular clumps. In the next stage, the spermatid nucleus becomes conspicuously spherical, its contents appear more finely homogeneous and the irregular clumps of chromatin are few. In the third stage, the nucleus gradually takes on an ellipsoidal shape as the antero-posterior axis shortens. The anterior part of its envelope becomes structurally modified in preparation for the adherence to it of the developing acrosome, and an implantation fossa forms posteriorly at the center of a second area where the nuclear envelope has been modified. The diameter of the chromatin fibrils again increases and those near the implantation fossa become oriented perpendicular to the nuclear envelope.
As the nucleus elongates in the fourth stage, a concentric sheath of microtubules closely surrounds it. These appear to depolymerize as the nuclear elongation proceeds, so that they are no longer present in the head region of the mature spermatozoon. The diameter of the chromatin fibrils increases to about 10 nm and they become oriented parallel to the long axis of the cell. With the decrease in the nuclear volume the fibrils unite laterally to form longitudinal sheets, and these finally merge in the mature spermatozoon into a mass of very dense chromatin without perceptible internal structure.     

Spermiogenesis and sperm structure in the crabUca tangeri (Crustacea,Brachyura), with special reference to the acrosome differentiation

Summary Early spermatids of the crabUca tangeri consists of the nucleus of granular chromatin and the cytoplasm, which contains a proacrosomal vesicle in close association with membrane lamellae. In the mid spermatids an invagination of the acrosomal vesicle membrane gives rise to the formation of the perforatorium, a spindle-shaped tubule which encloses tubular membranous structures. The pair of centrioles located at the base of the acrosome is not directly involved in perforatorial differentiation. The acrosomal vesicle shows a heterogeneous content composed of the operculum, the thickened ring, and three layers of different materials concentrically arranged around the perforatorium. During the late spermatid stage the nuclear profile differentiates numerous slender arms and the chromatin arranges into fibers. Membranous tubules from the cytoplasm become incorporated into the tubular structures of the perforatorium. The mature spermatozoon has the typical structure of the branchyuran sperm, with a complex acrosome, cupped by the nucleus, and a thin cytoplasmic band intervening between the former main elements. The centrioles are degenerate. The nuclear arms are unusually numerous (more than 20) and lack microtubules or microtubular derivatives.     

日本沼虾精子发生的研究

对日本沼虾精子发生全过程的电镜观察表明：精原细胞核染色质分散,胞质内有线粒休、内质网的分布。初级精母细胞核染色质块状,不均匀地分布于核中,内质同多小泡多。次级精母细胞核染色质大多分布于核膜内侧,内质网聚集成团,精细胞分化形成精子的早期,胞核增大,核侧形成内质同多小泡的聚合体;中期的核内染色质浓缩,同时形成空囊状结构,     

Transition of basic protein during spermatogenesis of <Emphasis Type="Italic">Fenneropenaeus chinensis</Emphasis> (Osbeck, 1765)

According to the ultrastructural characteristic observation of the developing male germ cells, spermatogenesis of the crustacean shrimp, Fenneropenaeus chinensis, is classified into spermatogonia, primary spermatocytes, secondary spermatocyte, four stages of spermatids, and mature sperm. The basic protein transition during its spermatogenesis is studied by transmission electron microscopy of ammoniacal silver reaction and immunoelectron microscopical distribution of acetylated histone H4. The results show that basic protein synthesized in cytoplasm of spermatogonia is transferred into the nucleus with deposition on new duplicated DNA. In the spermatocyte stage, some nuclear basic protein combined with RNP is transferred into the cytoplasm and is involved in forming the cytoplasmic vesicle clumps. In the early spermatid, most of the basic protein synthesized in the new spermatid cytoplasm is transferred into the nucleus, and the chromatin condensed gradually, and the rest is shifted into the pre-acrosomal vacuole. In the middle spermatid, the nuclear basic protein linked with DNA is acetylated and transferred into the proacrosomal vacuole and assembled into the acrosomal blastema. At the late spermatid, almost all of the basic protein in the nucleus has been removed into the acrosome. During the stage from late spermatid to mature sperm, some de novo basic proteins synthesized in the cytoplasm belt transfer into the nucleus without a membrane and almost all deposit in the periphery to form a supercoating. The remnant histone H4 accompanied by chromatin fibers is acetylated in the center of the nucleus, leading to relaxed DNA and activated genes making the nucleus non-condensed.     

THE FINE STRUCTURE AND CHEMICAL COMPOSITION OF NUCLEI DURING SPERMIOGENESIS IN THE HOUSE CRICKET : I. Initial Stages of Differentiation and the Loss of Nonhistone Protein

The early stages of nuclear differentiation in spermatids of the house cricket are described with regard to the fine structural elements and chemical components which occur. Particular attention is given to the loss of nonhistone protein from the nucleus and its relation to chromatin structure. Granular elements about 25 to 80 mµ in diameter, and fibers about 8 mµ in diameter occur in the earliest spermatid nucleus. The fibers are found in diffuse and condensed chromatin while granules are found only in diffuse material. DNA and histone parallel the chromatin fibers in distribution, while nonhistone protein and RNA parallel the granules in distribution. The granules and most of the nonhistone protein are lost, simultaneously, after the early spermatid stage. The protein loss occurs without detectable change in the structure of chromatin fibers. Chromatin fibers first show a structural change in mid spermiogenesis, when they become thicker and very contorted. Unusually thin fibers (about 5 mµ) also appear in mid spermatid nuclei; they are apparently composed of nonhistone protein and free of DNA and histone.     

Spermiogenesis in the bullfrog (Rana catesbeiana): a study of cytoplasmic events including cell volume changes and cytoplasmic elimination

The process by which spermatid cytoplasmic volume is reduced and cytoplasm eliminated during spermiogenesis was investigated in the bullfrog Rana catesbeiana. At early phases of spermiogenesis, newly formed, rounded spermatids were found within spermatocysts. As acrosomal development, nuclear elongation, and chromatin condensation occurred, spermatid nuclei became eccentric within the cell. A cytoplasmic lobe formed from the caudal spermatid head and flagellum and extended toward the seminiferous tubule lumen. The cytoplasmic lobe underwent progressive condensation whereby most of its cytoplasm became extremely electron dense and contrasted sharply with numerous electron-translucent vesicles contained therein. At the completion of spermiogenesis, many spermatids with their highly condensed cytoplasm still attached were released from their Sertoli cell into the lumen of the seminiferous tubule. There was no evidence of the phagocytosis of residual bodies by Sertoli cells. Because spermatozoa are normally retained in the testis in winter and are not released until the following breeding season, sperm were induced to traverse the duct system with a single injection of hCG. Some spermatids remained attached to their cytoplasm during the sojourn through the testicular and kidney ducts; however, by the time the sperm reached the Wolffian duct, separation had occurred. The discarded cytoplasmic lobe (residual body) appeared to be degraded with the epithelium of the Wolffian duct. It was determined that the volume of the spermatid was reduced by 87% during spermiogenesis through a nuclear volume decrease of 76% and cytoplasmic volume decrease of 95.3%.     

Ultrastructural study of spermatogenesis in the free-living marine nematode <Emphasis Type="Italic">Paracyatholaimus pugettensis</Emphasis> Weiser et Hopper, 1967 (Chromadorida: Cyatholaimidae)

Spermatogenesis and the morphology of mature sperm in the free-living chromadorid Paracyatholaimus pugettensis from the Sea of Japan were studied using transmission electron microscopy. In spermatocytes fibrous bodies (FBs) appear; in spermatids, the synthetic apparatus is located in the residual body, whereas the main cell body (MCB) houses the nucleus, mitochondria, and FBs. The nucleus of the spermatid consists of a loose fibrous chromatin that is not surrounded by a nuclear envelope; centrioles lie in the perinuclear cytoplasm. The plasma membrane of the spermatid MCB forms numerous filopodia. Immature spermatozoa from the proximal part of the testis are polygonal cells with a central nucleus. The latter is surrounded by mitochondria and FBs with poorly defined boundaries. The immature spermatozoa bear lamellipodia all along their surface. Mature spermatozoa are polarized cells with an anterior pseudopodium, which is filled with filaments that make up the cytoskeleton; the MCB houses a nucleus that is surrounded by mitochondria and osmiphilic bodies. In many ultrastructural characteristics, the spermatozoa of P. Pugettensis are similar to those of most nematode species studied so far (i.e., they are ameboid, have no acrosome, axoneme, or nuclear envelope). On the other hand, as in other chromadorids, no aberrant membrane organelles were observed during spermatogenesis of P. Pugettensis.Original Russian Text Copyright © 2004 by Biologiya Morya, Zograf, Yushin.