Intraflagellar transport is essential for spermiogenesis / 中华男科学杂志

Intra flagellar transport (IFT) is an evolutionarily conserved mechanism thought to be essential for the assembly and maintenance of most eukaryotic cilia and flagella. Development of the sperm tail axoneme resembles the cilia formation, which is organized by intraflagellar transport (IFT). Of all mammalian cells, sperm have the longest motile cilia, but few studies are reported on the role of IFT in the formation of sperm flagella and the mechanisms of IFT in spermiogenesis. This article focuses on the role of IFT in spermatogenesis and the importance of IFT in male fertility.

Histology and ultrastructure of male reproductive system of the Indian Spiny lobster Panulirus homarus (Decapoda: Palinuridae) / Histología y ultraestructura del sistema reproductor masculino de la langosta espinosa de la India Panulirus homarus (Decapoda: Palinuridae)

The spiny lobster Panulirus homarus, distributed along the Southeast and Southwest coasts of India, is an important commercial species having mariculture potential. Despite its importance, the structural and ultrastructure features of male gonads from this species have received scarce attention. Hence this study was aimed to describe the male reproductive tract of the species, using standard histological and electron microscopy techniques. Gonads from 94 specimens of P. homarus ranging in carapace length 37mm-92mm from vizhinjam (Southwest coast of India.) were obtained and processed for the study (Histology-70 numbers & ultrastructure-24 numbers). The male reproductive system consists of paired testis and vas deferens located in the cephalothoracic region. Macroscopically, the reproductive tract was observed in lobsters >35mm carapace length. In immature testis, spermatogonia were seen which measured 6.9-13.8µm in diameter and in the mature testis primary (5.4-5.9µm) and secondary spermatocytes (2.8-3µm) and spermatids (2.2-2.4µm) were present. Each vas deferens consists of proximal and distal portions. The spermatophoric mass begins formation in the proximal vas deferens. In the distal vas deferens the spermatophoric mass containing the spermatozoa are arranged in packets towards the periphery by the gelatinous matrix produced by the typhlosole. Ultrastructurally, the spermatogonia have lamina, nucleus and mitochondria like bodies, the primary spermatocytes have nucleus, dense chromatin and vacuolated cytoplasm and the spermatids have mitochondria, endoplasmic reticulum and centrioles. The endoplasmic reticulum and the nuclear envelope in the spermatids form the acrosome. The radial arms with microtubules are formed in association with the dense endoplasmic reticulum, near the nucleus. The sperm has a spherical structure with the nucleus, lamellar region, spikes and acrosome. This is the first comprehensive report of the structure of the male gametes and spermatogenesis in P. homarus from Indian waters.Rev. Biol. Trop. 62 (2): 533-541. Epub 2014 June 01.

La langosta espinosa Panulirus homarus, distribuida a lo largo de las costas sudeste y sudoeste de la India, es una especie de importancia comercial con gran potencial para la mari-cultura. A pesar de su importancia, las características estructurales y ultraestructurales de las gónadas masculinas de esta especie han sido poco estudiadas. Debido a esto, el objetivo de este estudio fue describir el aparato reproductor masculino de dicha especie, utilizando técnicas convencionales de microscopía histológica y electrónica. Se procesaron 94 ejemplares de P. homarus de vizhinjam (costa suroeste de la India) (70 individuos para histología y 24 para ultraestructura), cuyos caparazones variaron de 37 mm a 92 mm de longitud. El sistema reproductor masculino de esta especie consistió en un par de testículos y un conducto deferente situados en la región céfalo-torácica. Macroscópicamente, el aparato reproductor se observó en langostas con una longitud de caparazón >35mm. En testículos inmaduros, la espermatogonia midió 6.9-13.8μm de diámetro y se encontró presente en los testículos maduros primarios (5.4-5.9μm), espermatocitos secundarios (2.8 a 3 μm) y espermátidas (2.2-2.4μm). Cada conducto deferente consistió de porciones proximales y distales. La formación de la masa espermatofórica comienza en los conductos deferentes proximales. En el conducto deferente distal espermatofórico, la masa que contiene los espermatozoides está dispuesta en paquetes hacia la periferia, en una matriz gelatinosa producida por el tiflosol. Ultraestructuralmente, las espermatogonias presentan una lámina, núcleo y mitocondrias, los espermatocitos primarios tienen núcleo, cromatina densa y citoplasma vacuolado, mientras que las espermátidas tienen mitocondrias, retículo endoplasmático y centríolos. En las espermátidas, el retículo endoplásmico y la envoltura nuclear forman el acrosoma. Los brazos radiales con microtúbulos se forman en asociación con el retículo endoplásmico denso, cerca del núcleo. El esperma presenta una estructura esférica con el núcleo, la región laminar, las espinas y el acrosoma. Este documento constituye el primer informe exhaustivo de la estructura de los gametos masculinos y espermatogénesis en P. homarus de la India.

Ultrastructure of Spermatogenesis in the Testis of Paragonimus heterotremus

Lung fluke, Paragonimus heterotremus, is a flatworm causing pulmonary paragonimiasis in cats, dogs, and humans in Southeast Asia. We examined the ultrastructure of the testis of adult P. heterotremus with special attention to spermatogenesis and spermiogenesis using scanning and transmission electron microscopy. The full sequence of spermatogenesis and spermiogenesis, from the capsular basal lamina to the luminal surface, was demonstrated. The sequence comprises spermatogonia, spermatocytes with obvious nuclear synaptonemal complexes, spermatids, and eventual spermatozoa. Moreover, full steps of spermatid differentiation were shown which consisted of 1) early stage, 2) differentiation stage representing the flagella, intercentriolar body, basal body, striated rootlets, and electron dense nucleus of thread-like lamellar configuration, and 3) growing spermatid flagella. Detailed ultrastructure of 2 different types of spermatozoa was also shown in this study.

Spermatic characteristics and sperm evolution on the subfamily Stevardiinae (Ostariophysi: Characiformes: Characidae)

The monophyly and phylogenetic relationships among the members of Clade A characids (sensu Malabarba & Weitzman), later redefined and named as the Stevardiinae (sensu Mirande), have been primarily supported by traditional morphological and molecular data. Herein were examined, described and compared spermiogenesis and sperm ultrastructure of 12 species of the genera Boehlkea, Bryconacidnus, Bryconamericus, Creagrutus, Cyanocharax, Hemibrycon, Knodus, Odontostoechus, Piabina, and Rhinobrycon in order to evaluate possible phylogenetic signals and their potential use in recovering relationships of the Stevardiinae. All examined species demonstrated a nuclear rotation equal or less than 95º resulting in a lateral position of the double nuclear fossa and flagellum. In all species, sperm nuclei are slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and lies anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. All species analyzed herein and other species previously examined for these systems in the Stevardiinae share homologous sperm characteristics as evidenced by spermiogenesis, further supporting the monophyly of this clade. Spermatozoa of the Stevardiinae further show three morphotypes (M1, M2, M3) of arrangement of centrioles, flagellum, nucleus and midpiece, hypothesized as successively derived in a series of transformation from the most basal morphotype (M1).

A monofilia e filogenia dos membros do Clado A (sensu Malabarba & Weitzman), mais tarde redefinido e nomeado Stevardiinae (sensu Mirande), é suportada por dados morfológicos e moleculares. Aqui são examinadas, descritas e comparadas a espermiogênese e ultraestrutura do espermatozoide de 12 espécies dos gêneros Boehlkea, Bryconacidnus, Bryconamericus, Creagrutus, Cyanocharax, Hemibrycon, Knodus, Odontostoechus, Piabina e Rhinobrycon, a fim de avaliar possíveis sinais filogenéticos e seu uso potencial no estudo de relações filogenéticas em Stevardiinae. Em todas as espécies examinadas observa-se uma rotação nuclear igual ou menor que 95º, resultando em uma posição lateral da fossa nuclear dupla e do flagelo. Em todas as espécies o núcleo do espermatozoide é alongado em direção ao flagelo, o centríolo proximal é anterior e oblíquo ao centríolo distal e localiza-se parcialmente inserido na fossa nuclear, e a peça intermediária é pequena e fortemente assimétrica. Todas as espécies de Stevardiinae analisadas aqui e outras analisadas previamente compartilham características homólogas dos espermatozoides evidenciadas por sua espermiogênese, corroborando a monofilia deste clado. Os espermatozoides de Stevardiinae apresentam ainda três morfotipos (M1, M2, M3) de acordo com o arranjo dos centríolos, flagelo e peça intermediária, considerados como sucessivamente derivados em uma série de transformações a partir do morfotipo mais basal (M1).

Markiana nigripinnis (Perugia, 1891) as a putative member of the subfamily Stevardiinae (Characiformes: Characidae): spermatic evidence

The genus Markiana was until recently recognized as incertae sedis in the family Characidae, even though alternative placements for this genus have been advanced since its original description. More recently, it was hypothesized that Markiana nigripinnis is part of a clade informally named the Astyanax clade, indicating the putative close relationship of Markiana with the genus Astyanax. Examination of sperm ultrastructure of representatives of Astyanax and M. nigripinnis shows no evidence for this hypothesized close relationship. Rather, the spermatozoa of M. nigripinnis share characters found in spermatozoa of the non-inseminating members of the subfamily Stevardiinae, such as an angle of nuclear rotation equal to 85º resulting in a lateral position of the double nuclear fossa and flagellum. As with the non-inseminating Stevardiinae, sperm nuclei are also slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. Additionally, M. nigripinnis shares with the other members of the Stevardiinae the presence of only four teeth in the inner row of the premaxillary and a short triangular ectopterygoid, which is never more than twice the length of the palatine.

O gênero Markiana até recentemente foi reconhecido como incertae sedis na família Characidae, apesar da localização alternativa para este gênero desde sua descrição original. Mais recentemente, surgiu a hipótese de que Markiana nigripinnis faz parte de um clado chamado informalmente de "Astyanax clade", indicando a suposta relação de Markiana com o gênero Astyanax. A análise da ultraestrutura dos espermatozoides de representantes do gênero Astyanax e M. nigripinnis não mostra nenhuma evidência de estreita relação. Pelo contrário, os espermatozóides de M. nigripinnis compartilham o padrão encontrado nos espermatozoides dos membros não-inseminadores da subfamília Stevardiinae, tais como, um ângulo de rotação nuclear igual a 85º resultando em uma posição de lateral da fossa dupla nuclear e do flagelo. Assim como nos Stevardiinae não inseminadores, os núcleos dos espermatozoides também são ligeiramente alongados em direção ao flagelo, o centríolo proximal é anterior e oblíquo em relação ao centríolo distal e parcialmente inserido na fossa nuclear, e a peça intermediária é curta e fortemente assimétrica. Além disso, M. nigripinnis compartilha com os outros membros da Stevardiinae a presença de apenas quatro dentes na série interna da pré-maxila e um osso ectopterigoide curto e triangular, que nunca ultrapassa o dobro do comprimento do osso palatino.

Ultrastructural Aspects of Spermatids in Isogenic Black Mouse C57BL6J / Aspectos Ultraestructurales de las Espermátidas en el Ratón Negro Isogénico C57BL6

The objective of this study was to describe some changes in spermatids differentiating events during spermiogenesis, leading to spermatozoa final formation. The animals were sacrificed with ethylic acid inhalation and, then, testis fragments were collected, fixed in Karnovsky and post-fixed in osmium tetroxide. After dehydration, the sections were stained with uranyl acetate 2%. It was observed in early spermatids at Golgi phase, formation of acrosomal granule contained in the acrosomal vesicle, spheroidal nucleus with rugous reticulum around it, and Golgi apparatus made up of lamellae and vesicular structures. At cephalic hood phase, the granule suffers flattening and the marginal fossa is formed. In both phases, it was possible to observe the presence of multivesicular body. At acrosomal phase, the acrosomal system is set up, and several enzymes of endoplasmatic reticulum as well chromatoid body are observed in the cytoplasm. At the last phase, that is, maturation, the nucleus becomes more elongated, the endoplasmatic reticulum regresses, the Golgi apparatus approaches to the flagellum and mitochondrias align next to it.

El objetivo del estudio, fue describir algunas alteraciones producidas en la espermiogénesis, en los eventos que diferencian a las espermátidas y que llevan a la formación final de los espermatozoides. Los ratones fueron sacrificados con inhalación de éter etílico y, enseguida, se recolectaron fragmentos de testículos, los que fueron fijados en Karnovsky y tetróxido de osmio. Después de la deshidratación, los cortes fueron teñidos con acetato de uranilo al 2 %. En espermátidas jóvenes en la fase de Golgi se observan: formación del gránulo acrosómico contenido en la vesícula acrosómica, núcleo esferoidal con retículo rugoso a su alrededor, y aparato de Golgi formado por lamelas y estructuras vesiculares. En la fase de capuz cefálico, el gránulo sufre achatamiento y se forma la fosa marginal. En estas dos fases fue posible observar la presencia del cuerpo multivesicular. En la fase acrosómica se establece el sistema acrosómico, distingiéndose en el citoplasma muchas vesículas de retículo endoplasmático y cuerpo cromatoide. En la última fase, la de maduración, el núcleo se torna más alargado, el retículo endoplasmático retrae, el aparato de Golgi se aproxima al flagelo y las mitocondrias se alinean a lo largo de él.

Dichotomic spermiogenesis in Euptoieta hegesia(Lepidoptera: Nymphalidae)

Butterflies and moths produce enucleate (apyrene) and nucleate (eupyrene) spermatozoa. However, most studies oflepidopteran spermatogenesis and spermiogenesis have used only larvae and pupae. In this work, we used light andtransmission electron microscopy to examine spermiogenesis in males of the butterfly Euptoieta hegesia. Only adultmales were used, because this species has a long adult lifespan during which all cell stages can be observed. Male E.hegesia had a single fused testis with cysts that exclusively contained either apyrene or eupyrene cells. The mainevents of apyrene spermiogenesis included the formation, transformation and elimination of micronuclei, dense capformation, the development of mitochondrial derivatives and tail elongation. Eupyrene spermiogenesis involvedacrosome formation, nuclear condensation and elongation, extracellular appendage development, formation ofmitochondrial derivatives and tail elongation. The pattern and events of apyrene and eupyrene spermiogenesis in E.hegesia corroborate and complement data in the literature, particularly with regard to the intermediate developmentalstages of some structures, such as the acrosome, axoneme and extracellular appendages.

IMMUNOFLUORESCENCE ANALYSIS OF MANCHETTE DURING MOUSE SPERMIOGENESIS / 解剖学报

Objective To investigate the localization and the morphological changes of manchette during mouse spermiogenesis.Methods Immunofluorescence staining with FITC and costaining with DAPI were used to demonstrate the cellular localization of the manchette at different stages during mouse spermiogenesis.The structural changes of the manchette were observed during the maturing of the spermatid.Results Immunofluorescence staining showed that manchette existed exactly around the nuclei of the spermatids.Manchette began to form,when the shape of the nucleus changed from spherical to slightly elongated.While the nucleus of the spermatids condensed and elongated at later stages,manchette moved gradually to the caudal position of the spermatids.At last,the manchette diminished as the spermatids became mature.During mouse spermiogenesis,manchette underwent a transition from a cap-like to a tubular configuration.ConclusionThe formation and diminishment of the manchette is in step with the condensation and elongation of the nucleus of the spermatid.Both the structural and positional changes of the manchette coincide with the changes of the nucleus.These results imply that manchette might play an important role in mouse spermiogenesis.

Ethyl methanesulphonate induced changes in the differentiation, structure and functions of spermatozoa of the house rat, Rattus rattus L.

Intraperitoneal administration of 500 mg/kg and 625 mg/kg doses of the germ cell mutagen, ethyl methanesulphonate (EMS) in 5 consecutive days to the house rat, Rattus rattus caused a dose-dependent reduction in its body weight, cauda epididymides weight, concentration, motility and percentage of live spermatozoa with simultaneous increase in the percentage of their abnormal forms. Compared to 0·65% spermatozoa with abnormal heads in the cauda epididymidis of untreated control rats, 24·86% and 65·72% such spermatozoa were observed in rats on day 14 post treatment with 500 mg/kg and 625 mg/kg doses of EMS respectively. On day 28 post treatment corresponding values for abnormal spermatozoa were 16·21% and 14·32%. Similarly, spermatozoa with abnormal flagella increased from 0·78% in control rats to 9·25% and 5·75% on day 14 post treatment of 500 and 625 mg/kg doses of EMS respectively and declined to 2·91% and 2·40% on day 28 post treatment. Abnormality in the sperm head was mainly due to acrosomelessness and in the flagellum due to bending at proximal region. However, the main effect of EMS was the development of spermatozoa without or deformed acrosomes which may impair the fertility of rats. Analysis of various stages of differentiation of spermatozoa inthe testis revealed that population of preleptotene and pachytene spermatocytes and of round spermatids showed a gradual decline which became significantly less than controls on day 28 of EMS treatment. Occurrence of abnormal heads of testicular spermatids indicated that the sperm head abnormalities originated in the testis during late spermiogenesis.

ULTRASTRUCTURAL STUDIES ON SPERMIOGENESIS OF TAKYDROMUS SEPTENTRIONALIS / 解剖学报

Objective We studied the ultrastructure of seprmiogenesis of Takydromus septentrionalis. Methods After double fixed with 2.5% glutaric dialdehyde and 1% osmic acid,we observed the paraffin section and ultrathin section by light microscope and transmission electron microscopy respectively. Results There is a series of considerable changes in morphology and structure during the spermiogenesis of Takydromus septentrionalis.These changes include gradual nuclear elongation,chromatin condensation,formation of acrosome,development and fusion of mitochondria,cytoplasmic sloughing and flagellar formation.The course of spermiogenesis can be devided into four stages:Stage Ⅰ,the spermatid nucleus concaved when the preacrosomal vesicle reached the nucleus,increasingly,acrosomal vesicle came into being and acrosomal granules appeared at the bottom of acrosomal vesicle,in a thin layer of granular cytoplasm.the subacrosomal granule was formed,it contacts both the acrosomal granule and the outer nuclear membrane;Stage Ⅱ,the spermatid acrosomal vesicle flattened and chromatin condensed into fibers like short filaments and the nucleus prolonged; Stage Ⅲ,the spermatid nucleus went on prologing and the chromatin fibers in it went on condensing and the chromatin fibers was put in a order of parallel to the longitudinal axis of the nucleus.The proximal centriole and flagellum appeared.Stage Ⅳ,the longitudinal microtubules in Sertoli cells cytoplasm appeared around the sperm head and disappeared till sperm was mature.The acrosomal complex of spermatid was well-developed,and annulus was appeared.The nuclear chromatin condensed to the greatest extent and the nucleus was electron-dense.Conclusion It has great significance of nucleus and cell organelle as taxonomic character of Squamate lizard in the ultrastructure of spermiogenesis of Takydromus septentrionalis.