Ultrastructure of spermiogenesis and spermatozoa in Mesocastrada fuhrmanni Voltz, 1898 (Platyhelminthes, Rhabdocoela, Typhloplanoida)

Electron microscopy of the testes of the free-living flatworm Mesocastrada fuhrmanni collected from temporary freshwater ponds shows stages of spermiogenesis that are like other species of the Typhloplanidae. Spermiogenesis in Mesocastrada fuhrmanni is characterized by the presence, in the spermatid, of a differentiation zone underlain by peripheral microtubules and centered on two centrioles with an intercentriolar body. Two flagella of the 9+“1” pattern of the Trepaxonemata grow out in opposite directions from the centrioles. The flagella undergo a latero-ventral rotation, and a subsequent disto-proximal rotation of centrioles occurs in the spermatid. The former rotation involves the compression and the detachment of a row of cortical microtubules, and allows us to recognize a ventral from a dorsal side. Two features are of special interest at the end of differentiation: peripheral cortical microtubules lie parallel to the sperm axis near the anterior tip, but microtubules become twisted (about 40° with reference to the gamete axis) near the posterior extremity; in the same way, the posterior tip of the nucleus is spiralled. As far as we know, these features are observed for the first time in the Typhloplanidae. The pattern of spermiogenesis and the ultrastructural organization of the spermatozoon are compared with the available data on Typhloplanoida and in particular, species of the Typhloplanidae family.     

Les éléments cytoplasmiques au cours de la spermiogenèse du TritonPleurodeles waltlii Michah

Résumé L'origine et la morphogenèse des différents éléments de l'acrosome du spermatozode dePleurodeles waltlii ont été suivies et décrites depuis le tout début de la spermiogenèse. La formation de la vésicule acrosomienne et son évolution en une coiffe acrosomienne se fait selon le schéma classique. Son extrémité apicale se différencie tardivement en un bouton terminal et un crochet. Les trois parties de la coiffe diffèrent dans leur composition et leur structure fine.Les volumineux et complexes éléments situés sous la coiffe acrosomienne: axe, baguette puis manchon périphérique et manchon moyen, sont dépourvus de polysaccharides. Leur origine est envisagées. Ils sont comparés aux éléments situés dans l'espace sous-acrosomien des spermatozodes des autres vertébrés.

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The cytoplasmic elements during spermiogenesis in the triturusPleurodeles waltlii MichahI. Acrosome genesis

Summary The origin and the morphogenesis of the acrosome different parts ofPleurodeles spermatozoon, have been investigated and described from the early beginning spermiogenesis process. The acrosomal vesicle and acrosomal cap formation take place according to the classical scheme. The acrosomal anterior tip cap late differentiate in a blunt terminal knob and a hook. The three cap parts differ in their composition and fine structure.The large and complicated structure stretching under the acrosomal cap: axis, peripheral muff and middle muff, are devoided of polysaccharides; their origin is discussed. They are compared with the subacrosomal components lying in the other vertebrates spermatozoon subacrosomal space.

Equipe de Recherche Associée au C.N.R.S., E.R.A. n^o 129.     

拟目乌贼精子发生和精子的超微结构

应用扫描电镜和透射电镜观察了拟目乌贼(Sepia lycidas)精子的发生过程和超微结构。结果表明,精子发生经历了精原细胞、初级精母细胞、次级精母细胞、精细胞和成熟精子5个阶段,其中精细胞可以分为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ5个时期,精细胞Ⅱ期又可分为前期和后期。细胞核经历了一个横向收缩、纵向拉长的过程,由圆形或椭圆形,变为不规则的纺锤形、稍弯曲的长柱形;核内染色质由絮状,变为絮块状、致密颗粒状、细纤维状、粗纤维状和片层状,直至高电子密度均质状;顶体由圆形,变为头盔形、圆锥形、倒"U"字形,直至子弹头形;线粒体由空泡状经过融合和迁移,变为内嵴丰富的椭球形,形成不完全包围鞭毛的线粒体距。成熟精子全长101.28μm,由头部和尾部组成,头部呈长辣椒状,长7.73μm,宽1.51μm,由顶体和细胞核组成;尾部细长,为93.18μm,为典型的"9+2"结构,由中段、主段和末段三部分组成。     

Epithelial cadherin is present in bovine oviduct epithelial cells and gametes,and is involved in fertilization-related events

Fertilization is a calcium-dependent process that involves sequential cell–cell adhesion events of spermatozoa with oviduct epithelial cells (OECs) and with cumulus-oocyte complexes (COCs). Epithelial cadherin (E-cadherin) participates in calcium-dependent somatic cell adhesion; the adaptor protein β-catenin binds to the E-cadherin cytoplasmic domain and links the adhesion protein to the cytoskeleton. The study was conducted to immunodetect E-cadherin and β-catenin in bovine gametes and oviduct (tissue sections and OEC monolayers), and to assess E-cadherin participation in fertilization-related events. Epithelial cadherin was found in spermatozoa, oocytes, cumulus cells, and OEC. In acrosome-intact noncapacitated spermatozoa, E-cadherin was mainly localized in the apical ridge and acrosomal cap (E1-pattern; 84 ± 9%; mean ± standard deviation of the mean). After sperm treatment with heparin to promote capacitation, the percentage of cells with E1-pattern (56 ± 12%) significantly decreased; concomitantly, the percentage of spermatozoa depicting an E-cadherin staining pattern similar to E1-pattern but showing a signal loss in the acrosomal cap (E2-pattern: 40 ± 11%) increased. After l-α-lysophosphatidylcholine–induced acrosome reaction, E-cadherin signal was mainly localized in the inner acrosomal membrane (E3-pattern: 67 ± 22%). In IVM COC, E-cadherin was immunodetected in the plasma membrane of cumulus cells and oocytes, but was absent in the polar body. The 120 KDa mature protein form was found in protein extracts from spermatozoa, oocytes, cumulus cells, and OEC. β-Catenin distribution followed E-cadherin's in all cells evaluated. Epithelial cadherin participation in cell–cell interaction was evaluated using specific blocking monoclonal antibody DECMA-1. Sperm incubation with DECMA-1 impaired sperm–OEC binding (the number of sperm bound to OEC: DECMA-1 = 6.7 ± 6.1 vs. control = 29.6 ± 20.1; P < 0.001), fertilization with COC (% fertilized COC: DECMA-1 = 68.8 ± 10.4 vs. control = 90.7 ± 3.1; P < 0.05) or denuded oocytes (% fertilized oocytes: DECMA-1 = 57.0 ± 15.2 vs. control = 89.2 ± 9.8; P < 0.05) and binding to the oolemma (the number of sperm bound to oolemma: DECMA-1 = 2.2 ± 1.1 vs. control = 11.1 ± 4.8; P < 0.05). This study describes, for the first time, the presence of E-cadherin in bovine spermatozoa, COC, and OEC, and shows evidence of its participation in sperm interaction with the oviduct and the oocyte during fertilization.     

滇蛙多盘吸虫精子超微结构

利用透射电镜研究多盘吸虫精子的形态和结构。它属于单殖类中Ｐｏｌｙｏｐｉｓｔｈｏｃｏｔｙｌｅａ类型。精子细线形,含两根融入精子内的９＋１型轴丝,细长的细胞核,纤细的线粒体和微管。在第二根轴丝出现前的区段无微管的分布,具两根轴丝的主干段轴丝外无外侧管;细胞核消失后微管呈整圈排列;精子后部含糖原颗粒,背腹面中央向髓布内凹呈哑铃状并两侧向外突出形成波动膜;由精细胞则来的区段具外饰物。     

耳河螺生殖器官和精子的形态学研究

耳河螺「Ｒｉｖｕｌａｒｉａ ａｕｒｉｃｕｌａｔａ （Ｍａｒｔｅｎｓ）」为雌雄异体。雄性生殖器官由精巢,输精小管,贮精囊,输精管,前列腺和阴茎组成。精巢内有精子,精子有典型精子和非典型精子两种。扫描电镜下,典型精子头部呈螺旋状,尾端只有一根较粗壮;非典型精子头部和中部为棒状,尾部呈扫帚状,由８－１５根鞭毛组成。     

鲤鱼精子超微结构的研究

鲤鱼精子由头部,中片和尾部组成,头部的细胞核卵形,染色质致密。核中有些小空隙,空中的电子致密物质存在。中片紧连在核的后端。中片由中心粒复合体和袖套组成。中心粒复合体位于核后植入窝中,袖套一侧肥厚,一侧狭窄,袖套中有线粒体和囊泡。囊泡有二类,一类含有电子致密物质;另一类无电子致密物质。近袖套内膜处的细胞质中还存在着与内膜平行的膜,精子尾部从袖套腔中伸出。尾部的轴丝与基体相接。尾部的近核端多有许多囊泡     

The spermatozoon of Oikopleura dioica Fol (Larvacea,Tunicata)

Summary The spermatozoon of Oikopleura dioica is about 30 m long, with a spherical head, about 1 m wide, a 3 m long and 1 m wide midpiece, and a 25 m long tail with a tapered end piece. The head contains a nucleus with the chromatin volume limited to about 0.1 m³. A small acrosome is found in an anterior inpocketing, and a flagellar basal body in a posterior inpocketing of the nucleus. The midpiece contains a single mitochondrion with the flagellar axoneme embedded in a groove along its medial surface. The flagellar axoneme has the typical 9 + 2 substructure, and the basal body the typical 9+0 substructure. A second centriole and special anchoring fibres are absent.     

中国淡水蛏精子发生的超微结构研究

利用透射电镜观察了中国淡水蛏的精子发生和精子结构。描述了精子发生过程中各细胞形态结构的变化;揭示了细胞核、线粒体和项体等的演变过程。中国淡水蛏的精子经过精原细胞、初级精母细胞、次级精母细胞和精子细胞,最终限育为成熟的精子。精子为典型的原生型,由头部、中段和尾部构成。项体复合体位于精子头部前端,呈“⊥”形,精核近圆形;中段包括２个中心粒和４或５个紧密排列的椭圆形线粒体;尾部鞭毛断面为典型的“９＋２”