大鲵精子结构研究

为了解大鲵精子超微结构,应用扫描电镜和透射电镜开展了大鲵精子形态结构研究。结果显示:大鲵精子由头部、颈部和尾部3部分组成。精子总长216.36μm±9.93μm(n=30),头部长65.80μm±3.70μm(n=30),颈部较短,多不明显,尾部长153.52μm±3.22μm(n=30)。头部由顶体、穿孔器和细胞核组成;颈部包括核窝、近端中心粒及远端中心粒、线粒体、轴丝和轴纤维;尾部无明显分段,由轴丝、轴纤维、轴丝旁纤维和波动膜组成。大鲵精子内线粒体较少,可能与精子运动缓慢、精子活力维持时间短有关;成熟过程中精子细胞头部包围的胞质分泌物中含有一定数量的线粒体。     

北方山溪鲵精巢显微结构的年周期变化

2001、2003年1～12月自秦岭北坡的溪流中,共采集北方山溪鲵(Batrachuperus tibetanus)38尾(体重27～38g)做精巢切片,在光镜下观察精巢显微结构的年周期变化。结果表明：北方山溪鲵为非连续型精子发生,精原细胞增生有两个高峰期,分别在9～11月和翌年的3～5月,初级精母细胞的成熟分裂期在6月末至7月,精子形成期在7月末至8月。每个精巢小叶可明显地分为深层的非成熟区和浅层的成熟区。非成熟区为精原细胞的贮存区,可增殖并延伸为增殖区。增殖区再发育为成熟区,为精子形成和存储的区域。在精子排出后,成熟区转变为排空区,后者被新的增殖区更替。北方山溪鲵精巢所有小叶同步发育,无精子成熟波。     

大鲵精子的超微结构研究

本文运用透射电镜和扫描电镜研究了大鲵(Andrias davidianus)精子的超微结构,大鲵精子由头部(head),中片(midpiece)和尾部(tail)三部分组成。头部有棒状细胞核,核内染色质高度浓缩,细胞核前方呈细丝状,但非顶体结构。头部后端凹陷,称为植入窝(implantation fossa),植入窝内有线粒体和中心粒等细胞器结构,此区域为精子的中片。精子尾部细长,主要由轴丝和附属纤维(accessory fiber)组成,轴丝的外面具有波动膜。     

峨眉髭蟾精子形态结构及分类学意义

应用透射电镜、扫描电镜和光学显微镜对峨眉髭蟾(Vibrissaphoraboringii)精子的形态和超微结构研究的结果表明:峨眉髭蟾的精子具角蟾科物种精子基本的形态和结构特征,即精子头部呈螺旋状,尾部呈弯曲状;精子具锥形的顶体、纤维束构成的穿孔器、平行排列的中心粒和双轴丝;线粒体位于尾部;精子核窝不明显、无轴纤维和波动膜等特征。此外,对已有报道的角蟾科和无尾类物种精子的特征进行分析比较表明:(1)角蟾科精子细胞核呈螺旋状,中心粒平行排列,尾部具双轴丝等结构不同于无尾类其他科精子的结构,具有明显的科间差别;(2)角蟾科精子各部的量度,尾部线粒体的分布和数量,以及轴丝的排列等特征在属间和种间表现出明显的差异;(3)峨眉髭蟾和东南亚拟髭蟾指名亚种精子的形态和超微结构存在明显的差异。     

峨眉髭蟾精子形态结构及分类学意义

应用透射电镜、扫描电镜和光学显微镜对峨眉髭蟾(Vibrissaphora boringii)精子的形态和超微结构研究的结果表明：峨眉髭蟾的精子具角蟾科物种精子基本的形态和结构特征，即精子头部呈螺旋状，尾部呈弯曲状；精子具锥形的顶体、纤维束构成的穿孔器、平行排列的中心粒和双轴丝；线粒体位于尾部；精子核窝不明显、无轴纤维和波动膜等特征。此外，对已有报道的角蟾科和无尾类物种精子的特征进行分析比较表明：(1)角蟾科精子细胞核呈螺旋状，中心粒平行排列，尾部具双轴丝等结构不同于无尾类其他科精子的结构，具有明显的科间差别；(2)角蟾科精子各部的量度，尾部线粒体的分布和数量，以及轴丝的排列等特征在属间和种间表现出明显的差异；(3)峨眉髭蟾和东南亚拟髭蟾指名亚种精子的形态和超微结构存在明显的差异。     

西藏山溪鲵精子的形态

在光学显微镜下观察和测量了西藏山溪鲵 (Batrachuperustibetanus)精子 ,结果表明 ,该物种精子具有小鲵科科精子的共同特征 :由头、颈和尾组成。头部细直 ,颈部短而不显 ,尾部长曲 ;波动膜螺旋盘绕尾部轴棒 ,轴丝游离 ;顶体包括顶体鞘和穿孔器 ;颈部短。西藏山溪鲵精子种的特异性主要表现在量度方面 :其全长为 (2 89. 85± 1 3 0 2 ) μm ,顶体长为 (1 7. 96± 3. 69) μm ,头长为 (90 . 84± 8 .3 3 ) μm ,尾长 (1 81 .0 6±1 1. 5 3 ) μm ,头宽 (2. 75± 0. 3 7) μm ,其头部在已知精子形态的小鲵科物种中最宽。本文为该科物种的生态适应进化和系统学研究提供精子形态学依据。     

中国蟾蜍属精子形态比较

采用扫描电镜和光学显微镜观察了采自我国的蟾蜍属(Bufo)7种(亚种)的精子形态,对精子各部位量度进行了测量和计算。结果表明,该属7种(亚种)精子的形态基本相同,精子由头部、中片和尾部组成,头部细长微弯且前端渐尖,中片有球状突起,尾部长,由轴纤维、轴丝和波动膜构成。与已有报道的两栖动物的精子形态相比较,蟾蜍属精子与无尾类其他科精子形态差别较大,而与有尾类精子形态相似。本文认为两栖动物精子形态和量度在科间存在明显差异;两栖动物精子形态的差异可能与其繁殖模式有关。     

中国雨蛙精子结构及其在系统发育上的意义

研究了中国雨蛙（Ｈｙｌａｃｈｉｎｅｎｓｉｓ）精子的超微结构,并初步探讨其在系统发育上的意义,中国雨蛙精子由头部和尾部两部分组成,头部一有棒状的细胞核,核内染色质高度浓缩,细胞核前方有顶体。顶体圆锥状,顶体下腔之中一圆锥状的顶体下锥和细小的囊泡,精子尾部细长,主要由轴丝,致密纤维和线粒体组成,尾部没有波动膜。从蟾蜍科,雨蛙科和蛙科的精子结构看,无尾两栖类在进化过程中,精子结构趋向简单,雨蛙科精子的结     

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     

龙洞山溪鲵精子的超微结构

应用透射电镜和扫描电镜对龙洞山溪鲵(Batrachuperuslongdongensis)精子的超微结构进行观察和研究,探讨山溪鲵属以及小鲵科物种精子的结构特征,并探讨有尾两栖类精子结构特征的演化及其与生殖进化的关系。结果表明:1)龙洞山溪鲵的精子具小鲵科物种精子的共同特征,即精子无顶体钩,顶体呈三叶草状,尾部无线粒体,轴纤维粗大呈圆柱状等特征;2)龙洞山溪鲵精子核脊的形态结构与小鲵科其它属物种以及有尾类其它科物种精子的核脊存在明显的差别,由此可见核脊形态结构具有属或种的特异性。此外,与已有报道的有尾两栖类物种精子的结构特征进行分析比较表明:1)有尾类精子特征的分化与其受精方式的变化是一致的;2)精子结构特征支持隐鳃鲵超科为单系的推测     

The Ultrastructure of the Spermatozoa of Three Species of Myobatrachid Frogs (Anura,Amphibia) with Phylogenetic Considerations

Comparison of the spermatozoa of three genera of limnodynastines (Myobatrachidae: Anura) with those of 42 other species of frogs (in 11 families) previously examined allows the following phylogenetic inferences. The bufonoid neobatrachians (corresponding with the Arcifera of some classifications) form a monophyletic assemblage which is characterized by the possession, unique for the Anura, of a conical perforatorium; the rod-like perforatorium, which is plesiomorphic for tetrapods, is absent. Of the taxa investigated, the myobatrachids appear to be the sister-group of the remaining bufonoids, here termed eubufonoids (leptodactylids, rhinodermatids, hylids, and bufonids). The spermatozoa of the myobatrachids Limnodynastes, Neobatrachus, and Mixophyes are very similar to each other despite extremely varied fertilization biology. Symplesiomorphies for the Anura which they exhibit include the conical acrosome with subacrosomal material, the elongate, cylindrical nucleus, single flagellum and, paralleling this, an undulating membrane which is supported by a longitudinal element, the axial (major) fibre, the latter being accompanied in the midpiece by mitochondria. A myobatrachid synapomorphy appears to be the presence of a periaxial sheath enclosing the axial fibre of the flagellum. Forward extension of the axial fibre into the centriolar fossa in myobatrachids is seen elsewhere only exceptionally (in the bufonid Nectophrynoides). Bufonids, and most other eubufonoids including leptodactylids, differ apomorphically from Limnodynastes, and Neobatrachus in location of the mitochondria at the axonemal end (and in a collar) rather than the axial fibre end of the undulating membrane. In Mixophyes, mitochondria surround the nuclear-axonemal junction in a cytoplasmic droplet and are probably shed with this at maturity.     

Ultrastructure of the mature spermatozoa of caecilians (Amphibia: Gymnophiona)

The spermatozoa of Gymnophiona show the following autapomorphies: 1) penetration of the distal centriole by the axial fiber; 2) presence of an acrosomal baseplate; 3) presence of an acrosome seat (flattened apical end of nucleus); and 4) absence of juxta-axonemal fibers. The wide separation of the plasma membrane bounding the undulating membrane is here also considered to be apomorphic. Three plesiomorphic spermatozoal characters are recognized that are not seen in other Amphibia but occur in basal amniotes: 1) presence of mitochondria with a delicate array of concentric cristae (concentric cristae of salamander spermatozoa differ in lacking the delicate array); 2) presence of peripheral dense fibers associated with the triplets of the distal centriole; and 3) presence of a simple annulus (a highly modified, elongate annulus is present in salamander sperm). The presence of an endonuclear canal containing a perforatorium is a plesiomorphic feature of caecilian spermatozoa that is shared with urodeles, some basal anurans, sarcopterygian fish, and some amniotes. Spermatozoal synapomorphies are identified for 1) the Uraeotyphlidae and Ichthyophiidae, and 2) the Caeciliidae and Typhlonectidae, suggesting that the members of each pair of families are more closely related to each other than to other caecilians. Although caecilian spermatozoa exhibit the clear amphibian synapomorphy of the unilateral location of the undulating membrane and its axial fiber, they have no apomorphic characters that suggest a closer relationship to either the Urodela or Anura.     

The ultrastructure of the spermatozoa of Epipedobates flavopictus (Amphibia,Anura, Dendrobatidae), with comments on its evolutionary significance

We describe, for the first time, the spermatozoon ultrastructure of a dendrobatid frog, Epipedobates flavopictus. Mature spermatozoa of E. flavopictus are filiform, with a moderately curved head and a proportionally short tail. The acrosomal vesicle is a conical structure that covers the nucleus for a considerable distance. A homogeneous subacrosomal cone lies between the acrosome vesicle and the nucleus. The nucleus contains a nuclear space at its anterior end, and electron-lucent spaces and inclusions. No perforatorium is present. In the midpiece, the proximal centriole is housed inside a deep nuclear fossa. Mitochondria are scattered around the posterior end of the nucleus and inside the undulating membrane in the anterior portion of the tail. In transverse section the tail is formed by an U-shaped axial fiber connected to the axoneme through an axial sheath, which supports the undulating membrane. The juxta-axonemal fiber is absent. The spermatozoon of E. flavopictus has several characteristics not observed before in any anurans, such as a curved axial fiber, absence of a juxta-axonemal fiber, and presence of mitochondria in the typical undulating membrane. Our results endorse the view that, in anurans, the conical perforatorium and subacrosomal cone are homologous and that Dendrobatidae should be grouped within Bufonoidea rather than Ranoidea.     

Spermatozoon structure and motility in the anuran Lepidobatrachus laevis

Synthetic human gonadotropin releasing hormone (GnRH) injections were used for induction of spermatozoon release followed by cloacal lavage or mechanical stimulation of sperm release in Lepidobatrachus laevis . Light microscopic observations of Lepidobatrachus laevis spermatozoa indicated an acrosomal segment with a length of 4.1 μm delineated by an indentation, a nuclear region of 12.6 μm in length and a midpiece of 0.87 μm in length. The tail was 54.9 μm long by 1.35 μm wide with two lateral axial fibers and a central undulating membrane. At the electron microscopic level, the unusual tail had two complete axonemes that emanated from the distal centriole. The tail also contained two axial fibers 77 nm in diameter medial to the axonemes and was connected by an undulating membrane. An unusual accessory cell adherent to the head of the spermatozoon was noted in freshly obtained suspensions of spermatozoa. Spermatozoa with the accessory cell were motile and a subsequent loss of motility was correlated with the shedding of the accessory cell.     

挂榜山小鲵精子形态结构研究

应用扫描电镜和透射电镜对挂榜山小鲵(Hynobius guabangshanensis)精子的超微结构进行观察和研究.结果表明:1)挂榜山小鲵的精子形态具有小鲵科精子的共同特征:头部细直、有锥形顶体;颈部短而不明显,尾部细长、有波动膜;2)该种小鲵的精子超微结构具小鲵科物种精子的共同特征,即精子无顶体钩,顶体呈三叶草状,尾部无线粒体,轴纤维粗大呈圆柱状等;3)除精子全长(194.1±7.15μm)在小鲵科物种中属于中等外,挂榜山小鲵和本科其他物种的精子在形态量度学方面差异明显:其头部占全长的比例(22.98%)比其他已知小鲵科的物种都低,尾部占全长的比例(65.79%)比其他小鲵科物种都高.     

Ultrastructure of Spermiogenesis in Hyla japonica (Anura,Amphibia)

Spermiogenesis in Hyla japonica was examined using transmission electron microscopy. Features which have not been reported previously during spermiogenesis of anurans include: (1) the neck of pericentriolar material is well developed, (2) the perforatorium contains many microtubules, (3) the tail is composed of axoneme and axial rod, but has no undulating membrane. Such a structure has not been described in amphibians, although it occurs in fish and mammals, and (4) the modified microtubules have one to two long projections. So far they have not been observed in any species except Gerris and Aphyosemion. With the exception of the above characteristics, the spermatozoa of Hyla japonica are remarkably similar to those of Bufo sp.     

Umsatz von Lymphozyten in Blut und Lymphknoten der Ratte

Summary Mature spermatozoa from the seminal vesicles of adult Agriolimax reticulatus have been studied by means of phase contrast and electron microscopy; sperm were either live, or sectioned or mounted whole and shadowed with gold. The cell is of the typical pulmonate sperm type with a simple acrosome and a spiral nucleus comprising the head, and a tail which is ensheathed along its entire length by mitochondrion. The 9 peripheral fibrils of the axial complex show no indication of a double nature. Within the spermatheca or gametolytic gland breakdown of sperm occurs; the nucleus and axial fibre bundle of the flagellum survive the longest. The complexity of the flagellum and the relative simplicity of the acrosome are discussed in light of the ecology of the spermatozoa. Many problems concerning the functional physiology of the sperm organelles remain to be investigated.     

Ultrastructure variation in the spermatozoa of Pseudopaludicola frogs (Amphibia,Anura, Leptodactylidae), with brief comments on its phylogenetic relevance

The taxonomic history of the small frogs of the genus Pseudopaludicola from South America has been controversial. Phylogenetic inferences based on molecular data have identified four Pseudopaludicola clades, correlating with the known variation in karyotypes (2n = 22, 20, 18, and 16). In this study, the ultrastructure of the spermatozoa was analyzed in 12 species of the Pseudopaludicola, with the aim of describing their morphology and identifying characters that may contribute to a better understanding of the phylogenetic relationships. The spermatozoa presented marked differences in tail structures. The tails of the spermatozoa of the species with 2n = 22 chromosomes (Pseudopaludicola sp. 1 [P. pusilla group], Pseudopaludicola falcipes, P. mineira, and Pseudopaludicola saltica), as well as Pseudopaludicola ameghini and Pseudopaludicola ternetzi (2n=20), have juxta‐axonemal fibers, undulating membranes and axial fibers. In contrast, in the species with 2n = 18 (P. facureae, P. giarettai, Pseudopaludicola canga, P. atragula, and Pseudopaludicola sp. 2) and 2n = 16 (Pseudopaludicola mystacalis), there are no evident axial or juxta‐axonemal fibers, but a paraxonemal rod with a thick undulating membrane, which is shorter than that found among Pseudopaludicola species. The ultrastructural morphological differences observed in the spermatozoa of these species may be phylogenetically informative, given that they coincide with the consensus phylogeny of the group and appear to represent a progressive simplification of the spermatozoon. J. Morphol. 276:1495–1504, 2015. © 2015 Wiley Periodicals, Inc.