Mouse model of chorea-acanthocytosis exhibits male infertility caused by impaired sperm motility as a result of ultrastructural morphological abnormalities in the mitochondrial sheath in the sperm midpiece.

Chorea-acanthocytosis (ChAc) is an autosomal recessive hereditary disease characterized by neurodegeneration in the striatum and acanthocytosis caused by loss-of-function mutations in the Vacuolar Protein Sorting 13 Homolog A (VPS13A) gene, which encodes chorein. We previously produced a ChAc-model mouse with a homozygous deletion of exons 60-61 in Vps13a, which corresponded to the human disease mutation. We found that male ChAc-model mice exhibited complete infertility as a result of severely diminished sperm motility. Immunocytochemical study revealed that chorein-like immunoreactivity is abundant only in the midpiece, mitochondria-rich region, of the sperm of wild type mice. They showed no significant differences from wild types in terms of the adenosine 5'-triphosphate (ATP) concentration of their sperm, sperm count, or sexual activity. Electron microscopy revealed abnormal ultrastructural morphology of the mitochondria in the midpiece of sperm from ChAc-model mice. These results suggest that chorein is essential in mouse sperm for the maintenance of ultrastructural mitochondrial morphology and sperm motility.

Spermicidal efficacy of VRP, a synthetic cationic antimicrobial peptide, inducing apoptosis and membrane disruption.

Presently available contraceptives are mostly hormonal or detergent in nature with numerous side effects like irritation, lesion, inflammation in vagina, alteration of body homeostasis, etc. Antimicrobial peptides with spermicidal activity but without adverse effects may be suitable alternatives. In the present study, spermicidal activity of a cationic antimicrobial peptide VRP on human spermatozoa has been elucidated. Progressive forward motility of human spermatozoa was instantly stopped after 100 µM VRP treatment and at 350 µM, all kinds of sperm motility ceased within 20 s as assessed by the Sander-Cramer assay. The spermicidal effect was confirmed by eosin-nigrosin assay and HOS test. VRP treatment (100 µM) in human spermatozoa induced both the intrinsic and extrinsic pathways of apoptosis. TUNEL assay showed VRP treatment significantly disrupted the DNA integrity and changed the mitochondrial membrane permeability as evident from MPTP assay. AFM and SEM results depicted ultra structural changes including disruption of the acrosomal cap and plasma membrane of the head and midpiece region after treatment with 350 µM VRP. MTT assay showed after treatments with 100 and 350 µM of VRP for 24 hr, a substantial amount of Lactobacillus acidophilus (about 90% and 75%, respectively) remained viable. Hence, VRP being a small synthetic peptide with antimicrobial and spermicidal activity but tolerable to normal vaginal microflora, may be a suitable target for elucidating its contraceptive potentiality.

Sperm attributes and morphology on Rusa timorensis: light and scanning electron microscopy.

This study provides standard information on the attributes of sperm and describes the surface structure of normal and abnormal spermatozoa of Rusa timorensis. Two fertile stags were used as the source of semen collected during the first breeding season commencing from April 5 to July 2, 2012. Another five stags were used as the source of semen collected during the second breeding season commencing from April 1 to June 27, 2013. Semen samples were collected from the stags using an electro-ejaculator. The ejaculate was processed and samples prepared for light and scanning electron microscopy (SEM) according to standard methods. No significant difference (P>0.05) was found between sperm attributes in comparison between different stags and different months of the fertile seasons. The results of this study have also demonstrated that there are no differences in size, shape and surface structure between spermatozoa of the different stags and different months of the fertile seasons. Sperm attributes (volume, pH, sperm concentration, general motility, progressive motility and viability) were 2.2±0.29 ml, 7.2±0.17, 886.3±39.7×10(6) spermatozoa/ml, 78.7±2.01%, 80.8±1.85% and 83.2±0.85%, respectively. Morphological analysis showed low percentage of abnormal spermatozoa 13.9±2.88%. Scanning electron microscopy revealed spermatozoa which consisted of a flat paddle-shaped head, short neck and a tail, which was subdivided into midpiece, principal piece and endpiece. The average spermatozoon was 66.2±0.69 µm in total length. The flat paddle-shaped head was 7.8±0.28 µm long, 4.2±0.15 µm at its widest width, 2.4±0.18 µm basal width and 0.7±0.0 2µm thick. As for the tail, the midpiece length was 13.2±0.14 µm, 0.6±0.04 µm in diameter; the principal piece was 42.6±0.04µm, and 2.8±0.06 µm for the endpiece. Abnormal spermatozoa such as tapered head, microcephalic head, decapitated spermatozoa and bent tails were observed. Results provide standard information useful for development of strategies for semen cryopreservation and assisted reproductive technology in this species.

A re-evaluation of sperm ultrastructure in the emu, Dromaius novaehollandiae.

Existing reports on sperm structure in the emu do not adequately illustrate or describe all the salient ultrastructural features necessary for a meaningful comparison of normal and abnormal sperm in this species. As sperm morphology forms an important parameter in determining semen quality, and in view of the proposed role of artificial insemination in the farming of ratites, this article re-evaluates and complements the existing data on the topic, provides a fully illustrated description of emu sperm ultrastructure, and documents some unreported morphologic features. Conventional transmission and scanning electron microscopy and high resolution scanning electron microscopy were used to describe the ultrastructure of sperm harvested from the distal deferent duct of sexually mature birds slaughtered during the breeding season. In addition to broadly confirming the basic ultrastructural characteristics previously described for emu sperm, this study revealed a number of unreported morphologic features. These included distinct differences in surface properties between the acrosome and nucleus, the presence of a thread-like appendage near the base of the nucleus, variable positioning of the annulus relative to structures located at the midpiece-principal piece junction and regional differentiation of the principal piece. Although the emu displayed similar basic morphologic features to sperm of other ratites and the tinamou, marked structural peculiarities were obvious, notably the lack of an endonuclear canal and a perforatorium and the presence of significantly more mitochondria in the midpiece coupled with an absence of intermitochondrial cement. Although the broad morphologic features of emu sperm would appear to add credence to the general view that the ratites, together with the tinamous, form a monophyletic group at the base of the avian phylogenetic tree, it is also clear that emu sperm are distinctly different from those of the ostrich, rhea, and tinamou which together share morphologic affinities. This observation may lend some support to the alternate view that the Australasian ratites represent a separate clade that developed independently from flightless ancestors.

Cellular ontogeny of RBMY during human spermatogenesis and its role in sperm motility.

The Y-chromosome-encoded gene RBMY (RNA-binding motif on Y) is a male germline RNA-binding protein and is postulated to be a RNA-splicing regulator. In order to understand the roles of RBMY in different stages of male gamete maturation, the present study aimed at determining its cellular expression during spermatogenesis, spermeogenesis and in mature spermatozoa. In the spermatogonia (cKIT-positive cells), RBMY immunolocalized as two distinct foci, one in the nucleolus and the other in the subnuclear region; in the spermatocytes (cKIT-negative cells), the nucleus had punctuate staining with a subnuclear foci; in the pachytene cells, the protein was localized as a punctuate pattern in the nucleus spread along the elongating chromosomes. In the round and the elongating spermatids, the protein expression was polarized and restricted to the cytoplasm and in the developing mid-piece. In testicular and ejaculated sperm, RBMY was localized to the mid-piece region and weakly in the tail. Incubation of spermatozoa with the RBMY antibody reduced its motility. The spatial differences in expression of RBMY in the germ cells and the presences of this protein in post-meiotic cells and in transcriptionally inert spermatozoa suggest its involvement in multiple functions beyond RNA splicing. One such possible function of RBMY could be its involvement in sperm motility.

The ultrastructural characteristics of the spermatozoa stored in the cauda epididymidis in Chinese soft-shelled turtle Pelodiscus sinensis during the breeding season.

The ultrastructure of spermatozoa in cauda epididymidis of soft-shelled turtle, P. sinensis during breeding season was investigated by light microscopy (LM) and electron microscopy (TEM and SEM). The mature spermatozoa appeared elongated and filiform. In general, the turtle spermatozoon contains a characteristic head, midpiece and tail, similar in morphology to that of birds, amphibians and other reptiles. However, several features are unique. These include (1) three intranuclear tubules containing dense core extend from the subacrosomal cone through the rostral nucleus and deep into the nuclear body; (2) the midpiece is composed of 40 mitochondria which present a staggered rings-and-columns arrangement (8 parallel rings and 5 columns); (3) unusual spherical mitochondria with a dense core are surrounded by 8-10 concentric layers of cristae. Surprisingly, about 21.4±3.6 percent immature spermatozoa with normal morphology are also observed in this season. Different from the mature spermatozoa, a variable amount of cytoplasm droplets are attached to the immature spermatozoa under SEM. Some spermatozoa still show the tail coiled tightly around the cytoplasm. These spermatozoa in transverse sections under TEM, showed a large amount of cytoplasm wrapped by plasma membrane; even some free mitochondria and higher electron density material still seen in the cytoplasm. Among the immature spermatozoa, most of them possess a cytoplasmic droplet which is located eccentrically on the midpiece, and contains a lot of lipid droplets in addition to hollow vesicles. Lipid droplets are closely associated with mitochondrial membranes and may function in the formation or degradation of mitochondria. These immature spermatozoa may be the dormant cells, but whether or not they can fertilize the ovum or not is unknown. Thus, in the present study we hypothesized that the cauda epididymidis might be involved in the sperm maturation in this species.

Three-dimensional structure of the bovine sperm connecting piece revealed by electron cryotomography.

The sperm connecting piece is a complex structure that, from a mechanical perspective, appears to play a role in stabilizing the proximal part of the sperm tail. We report the three-dimensional structure of the intact bovine sperm connecting piece, revealing an intricate, asymmetrical architecture with the segmented columns held together by filamentous linkages. The columns fuse, at the proximal end, with each other into structures that form the centriolar vault, and at the distal end, with the outer dense fibers (ODFs). The grouping of the fibers into these structures is consistent with bending only in the plane of the head. Structures reminiscent of the proximal centriole were observed in the vault, while the association of a novel bar structure with ODFs 3 and 8 organizes the distal centriolar vault. It has been proposed that the elastic compliance of the connecting piece provides the underlying mechanism behind initiation of the sperm beat cycle and bend propagation. According to the basal sliding theory of sperm movement, distortion of the connecting piece may store energy that initiates a new beat. The intersegment linkers could serve as mechanosensitive elements that regulate alternation of the sperm tail's bending direction in the beat cycle in addition to providing structural stabilization for the connecting piece segmented structures. On the other hand, our video recordings of the bull sperm movement show little bending of the head with respect to the tail, so it appears that there may be normally little strain within the connecting piece.

Effect of increasing trypsin concentrations on seminal coagulum dissolution and sperm parameters in spider monkeys (Ateles geoffroyi).

Seminal coagulum formation in spider monkeys (Ateles geoffroyi) interferes with the efficient recovery and evaluation of spermatozoa. The main objective was to assess the effect of increasing concentrations of trypsin on dissolution of seminal coagulum and spermatic parameters. Seminal coagulum was incubated at 37 °C without trypsin or in the presence of increasing trypsin concentrations (0.1%, 1.0%, and 5.0%). For each sample, coagulum dissolution time was measured, and sperm concentration, viability, motility, and morphology were evaluated using light microscopy and/or transmission electronic microscopy (TEM). Trypsin concentrations of 1.0% and 5.0% more rapidly liquefied seminal coagulum, averaging 32 and 21 min, respectively, compared with nontrypsinized controls, with maintenance of greater sperm viability (70.8% and 72.5%, respectively). Coagulum treated with 1.0% trypsin and the liquid ejaculate fraction averaged higher sperm motility (40.1% and 55.6%, respectively) than control samples, and both 1.0% and 5.0% trypsin treatment allowed recovery of increased numbers of motile spermatozoa. There was greater sperm fragmentation at the head and midpiece level after treatment with 1.0% and 5.0% trypsin (55.8% and 55.9%); however, the percentage of normal morphology in structurally intact spermatozoa did not differ relative to controls. With transmission electronic microscopy imaging, there were similar percentages of spermatozoa with plasma membrane swelling in the midpiece and acrosomal regions in trypsin-treated samples and controls. In conclusion, trypsin treatment of spider monkey seminal coagulum exerted a concentration-dependent effect on dissolution time and various spermatic parameters. Higher trypsin concentrations caused more rapid liquefaction of coagulum and recovery of greater numbers of motile spermatozoa, but may adversely affect fragmentation of spermatozoa and could compromise sperm function and cryopreservation potential.

[A comparative study of sperm morphology evaluation criteria by the fifth and fourth editions of WHO Laboratory Manual].

OBJECTIVE: To compare the criteria of sperm morphology evaluation in the fifth edition of WHO Laboratory Manual for the Examination and Processing of Human Semen and those in the fourth edition, and to know the changes in the criteria of sperm morphology evaluation in the new edition. METHODS: Nine technicians from Zhejiang Human Sperm Bank evaluated the morphology of 1 000 spermatozoa in 96 sperm morphological pictures according to the criteria in the fourth and fifth editions of WHO Laboratory Manual, respectively. RESULTS: The percentage of morphologically normal sperm by the criteria of the fifth edition was (26.50 +/- 5.06)%, significantly higher than (11.39 +/- 3.17)% by the fourth edition (P < 0.05), while the rates of sperm head and tail defects based on the former were (64.26 +/- 7.66)% and (10.92 +/- 2.03)%, significantly lower than (76.11 +/- 8.18)% and (39.89 +/- 3.85)% according to the latter (P < 0.05). There were no significant differences in the rates of sperm midpiece defects and excessive residual cytoplasm by the fifth and fourth editions ([16.46 +/- 3.08]% vs [15.22 +/- 3.51 ]% and [4.24 +/- 1.66]% vs [3.87 +/- 1.68]%, P > 0.05). CONCLUSION: The criteria of sperm morphology evaluation in the fifth edition of WHO Laboratory Manual are less strict than those in the fourth, and the percentage of morphologically normal sperm is higher according to the fifth edition.

Patterns of genetic variation and covariation in ejaculate traits reveal potential evolutionary constraints in guppies.

Ejaculates comprise multiple and potentially interacting traits that determine male fertility and sperm competitiveness. Consequently, selection on these traits is likely to be intense, but the efficacy of selection will depend critically on patterns of genetic variation and covariation underlying their expression. In this study, I provide a prospective quantitative genetic analysis of ejaculate traits in the guppy Poecilia reticulata, a highly promiscuous live-bearing fish. I used a standard paternal half-sibling breeding design to characterize patterns of genetic (co)variation in components of sperm length and in vitro sperm performance. All traits exhibited high levels of phenotypic and additive genetic variation, and in several cases, patterns of genetic variation was consistent with Y-linkage. There were also highly significant negative genetic correlations between the various measures of sperm length and sperm performance. In particular, the length of the sperm's midpiece was strongly, negatively and genetically correlated with sperm's swimming velocity-an important determinant of sperm competitiveness in this and other species. Other components of sperm length, including the flagellum and head, were independently and negatively genetically correlated with the proportion of live sperm in the ejaculate (sperm viability). Whether these relationships represent evolutionary trade-offs depends on the precise relationships between these traits and competitive fertilization rates, which have yet to be fully resolved in this (and indeed most) species. Nevertheless, these prospective analyses point to potential constraints on ejaculate evolution and may explain the high level of phenotypic variability in ejaculate traits in this species.

Sperm ultrastructure, morphometry, and abnormal morphology in American black bears (Ursus americanus).

The objective of this study was to describe sperm ultrastructure, morphometry, and abnormal morphology in American black bears. Electroejaculation was successful in 53.8% (7/13) of the attempts, but urine contamination was common. Epididymal sperm samples were also obtained from five bears. Sperm had a paddle-like head shape and the ultrastructure was similar to that of most other mammals. The most striking particularity of black bear sperm ultrastructure was a tightening of the nucleus in the equatorial region. Although the differences were not significant in all bears, the overall decrease in sperm nucleus dimensions during transport from the caput epididymis to the cauda suggested increasing compaction of the nucleus during maturation. For ejaculated sperm, nucleus length, width, and base width were 4.9, 3.7, and 1.8 µm, respectively, whereas sperm head length, width, and base width were 6.6, 4.8, and 2.3 µm, and midpiece, tail (including midpiece), and total sperm lengths were 9.8, 68.8, and 75.3 µm. Evaluation of sperm cytoplasmic droplets in the epididymis revealed that proximal droplets start migrating toward a distal position in the caput epididymis and that the process was mostly completed by the time sperm reached the cauda epididymis. The proportion of morphologically normal sperm in the ejaculate was 35.6%; the most prevalent sperm defects were distal cytoplasmic droplets and bent/coiled tails. The morphology of abnormal sperm and the underlying ultrastructural defects were similar to that in other large domestic animals thus suggesting similar underlying pathogenesis of specific sperm defects and similar effects on fertility.

Sperm midpiece length predicts sperm swimming velocity in house mice.

Evolutionary biologists have argued that there should be a positive relationship between sperm size and sperm velocity, and that these traits influence a male's sperm competitiveness. However, comparative analyses investigating the evolutionary associations between sperm competition risk and sperm morphology have reported inconsistent patterns of association, and in vitro sperm competition experiments have further confused the issue; in some species, males with longer sperm achieve more competitive fertilization, while in other species males with shorter sperm have greater sperm competitiveness. Few investigations have attempted to address this problem. Here, we investigated the relationship between sperm morphology and sperm velocity in house mice (Mus domesticus). We conducted in vitro sperm velocity assays on males from established selection lines, and found that sperm midpiece size was the only phenotypic predictor of sperm swimming velocity.

The shape of the sperm midpiece in intracytoplasmic morphologically selected sperm injection relates sperm centrosomal function.

PURPOSE: To evaluate whether the morphology of the sperm midpiece observed by high magnification microscopy relates to sperm centrosomal function. METHODS: Sperm selected by conventional microscopy were defined as controls. By high magnification microscopy, sperm with straight midpieces were defined as Group 1, while those with tapering midpieces were defined as Group 2. Heterologous ICSI of human sperm into bovine oocytes was used to assess human sperm centrosomal function and analysis of sperm aster formation. RESULTS: The total rate of sperm aster formation was 80.5% in Group 1, which was significantly higher (P < 0.05) than the rate of 33.3% seen for Group 2. Furthermore, sperm aster formation rates tended to be higher for Group 1 than for the controls. CONCLUSIONS: This study demonstrates improvement of sperm aster formation rates by selecting sperm on the basis of midpiece morphology. The injection of selected sperm bearing morphologically straight midpieces may contribute to improved expression of sperm centrosomal function, providing a positive effect on fertilization after ICSI.

Ultrastructure of the mature spermatozoon of the bivalve Estellarca olivacea (Mollusca: Bivalvia: Arcidae) and its phylogenetic implications.

Ultrastructure of mature spermatozoa of Estellarca olivacea was studied by transmission electron microscopy and its phylogenetic implications are discussed for the first time in this paper. The mature spermatozoon is composed of a head which contains a cone-shaped acrosome, a round nucleus and a tail region. The subacrosomal space is less electron dense which contains a homogeneous material. No axial rod and a basal plate were observed in subacrosomal space. No anterior invagination exists in the nucleus, but an inverted shallow V-shaped posterior invagination is visible. Nuclear lacunae could be seen clearly although the nucleus is highly condensed. Within the mid-piece of the spermatozoon there exist five spherical mitochondria while the long whip-like end portion is composed of an axoneme with the typical 9+2 structure. The spermatozoon of Estellarca olivacea is a product of the evolution of the reproductive system of the family Arcidae. Whether the particular acrosome, subacrosomal space, or the highly condensed nucleus might be adaptations of high fertilization rate in the particular environment of this species is discussed.

Preparation and ultrastructure of spermatozoa from green poison frogs, Dendrobates auratus, following hormonal induced spermiation (Amphibia, Anura, Dendrobatidae).

Few ultrastructural studies have been performed on members of the Dendrobatidae, although such investigations can be useful for the understanding of reproductive patterns, as a diagnostic method for males in breeding programs for endangered amphibians and for phylogenetic analysis. The sperm ultrastructure of the Green Poison Frog, Dendrobates auratus, from Panama is described following induced spermiation in living animals. To date only testicular spermatozoa in other dendrobatid frogs have been analysed. Moreover, an electron microscopic preparation method (transmission and scanning electron microscopy) for dendrobatid sperm cells in low concentration is presented. Sperm cells from stimulated frogs (100 IU human chorionic gonadotropin, hCG, twice at an interval of 1h) were recovered via cloaca lavage using 600 microl isotonic phosphate-free amphibian saline (IPS). Centrifuged flushings (5 min, 173 x g) were deposited on microscopic slides. Adherent spermatozoa were treated with Karnovsky fixative (overnight, 4 degrees C). After postfixation (2h, 1% osmium tetroxide), samples were dehydrated in series of ascending acetones (30-100%). For transmission electron microscopy sperm cells were encapsulated using Epon and 1.5% 2,4,6-tris(dimethylaminomethyl)phenol (DMP 30). Ultrathin sections (70 nm) were cut and stained with uranyl acetate (30 min) and lead citrate (5 min). Sperm cells are filiform with a 21.1+/-2.7 microm long and arcuated head and a single tail (35.0+/-4.2 microm length). Their acrosomal complex is located at the anterior portion of the head and consists of the acrosomal vesicle which has low electron density, and the subjacent electron-dense subacrosomal cone. In transverse section, the nucleus is circular (1.9+/-0.2 microm diameter) and conical in longitudinal section. It is surrounded by several groups of mitochondria. The chromatin is highly condensed and electron-dense but shows numerous electron-lucent inclusions. A short midpiece has a mitochondrial collar with a proximal and a distal centriole. The latter gives rise to the axoneme which alone forms the flagellum. The sperm ultrastructure of D. auratus differs from that of other Dendrobatidae because of the absence of a nuclear space and the absence of the undulating membrane associated with an axial fibre. This tail conformation is found in the Ranoidea but not in the Bufonoidea. These results show that the spermatozoa of D. auratus are the first within the Dendrobatidae without accessory tail structures. Methods of using sperm samples from hormonal treated frogs for ultrastructural studies is not only reasonable to examine e.g. amphibian phylogeny without killing frogs threatened with extinction but allows investigations in the field of assisted reproduction and male fertility for example in conservation programs for endangered amphibians.

Compliance in the neck structures of the guinea pig spermatozoon, as indicated by rapid freezing and electron microscopy.

Electron microscopy has been used to investigate whether the transversely striated columns of the connecting piece in the neck region of guinea pig spermatozoa, undergo lengthening and shortening as a result of the forces generated during motility. Motile spermatozoa were subjected to near-instantaneous rapid freezing, followed by freeze-substitution fixation and epoxy embedment. Thin sections passing longitudinally through the striated columns revealed that the periodicity was indeed variable. The repeat period, taken to have an unstressed width of 60 nm, could be found extended to 75 nm in some specimens, and reduced to 54 nm in others. The estimates of the coefficients of variation were 6.6% for the width of the 'dense' band and 33.5% for the 'pale' band. The 'pale' band in the extended state showed longitudinal striae. Such variations in length, which - it is suggested - are physiological, and passively induced, would have functional implications for the flagellum - for both bend initiation and bend growth. Also, hypothetically, any mechanism that could increase the degree of compliance in these columns, such as perhaps phosphorylation of the constituent proteins, could permit the flagellum to develop the exaggerated bend angles and asymmetries of the 'hyperactivated' state.

Expression of the G-protein alpha-subunit gustducin in mammalian spermatozoa.

Although chemotaxis has been proposed to guide sperm to egg throughout the animal kingdom, sperm attractants released from mammalian eggs have not been identified. Since the G protein subunit alpha-gustducin is accepted as a marker of chemosensitive cells, attempts were made to explore whether alpha-gustducin is also expressed in spermatozoa of mammals. Immunohistochemical approaches using an anti-alpha-gustducin-specific antibody revealed the most intense immunoreactivity in differentiating spermatids. Further evidence for the alpha-gustducin expression was obtained analyzing testicular and sperm-derived tissue preparations in western blot analyses. To elucidate whether alpha-gustducin is retained in mature spermatozoa, epididymal mouse and rat sperm were subjected to immunocytochemistry as well as immunogold electron microscopy. A specific staining was obtained within the circumference of the midpiece-localized mitochondria, on the axoneme and the outer dense fibers surrounding the microtubules of this region, whereas no labeling was detectable in the end piece regions. The analysis of ejaculated bovine and human sperm revealed a comparable segmental distribution pattern for alpha-gustducin. Although a possible function for alpha-gustducin has yet to be determined, the axonemal-associated localization within the midpiece and principal piece of different mammalian spermatozoa raises the possibility that this G protein alpha-subunit may process intracellular signals controlling sperm motility.

[Ultrastructural aspects of the spermatozoon abnormalities on infertile men in Senegal]. / Aspects ultrastructuraux desanomalies du spermatozoïde chez les hommes hypofeconds au Sénégal.

Oligo-astheno-teratozoospermia being frequently observed (44,1%) in male subjects among hypofertiles couples of the sample population, we studied it at the ultrastuctural level. Our investigations have shown that, in addition to morphological and functional abnormalities, spermatic cells in said persons also presented serious ultrasructural disorders which would cause sterility. However in the absence of specific codified treatment for the majority of abnormalities found in sperms and given the high cost of the utrastructural analysis, we propose to limit our study to precise cases of male sterility through routine sample evaluations.

Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy.

BACKGROUND INFORMATION: Available data concerning the sperm morphology of teleost fishes demonstrate wide variation. In the present study, the spermatozoa of Siberian sturgeon (Acipenser baerii Brandt, 1869), a chondrostean fish, was investigated. In contrast with teleost fish, chondrostean spermatozoa have a head with a distinct acrosome, whereas other structures, such as a midpiece and a single flagellum, are present in spermatozoa of most species. RESULTS: The average length of the head including the acrosome and the midpiece was 7.01+/-0.83 microm. Ten posterolateral projections derived from the acrosome were present on a subacrosomal region, with mean lengths of 0.94+/-0.15 microm and widths of 0.93+/-0.11 microm. The nucleus consisted of electrodense homogeneous nuclear chromatin. Three intertwining endonuclear canals, bound by membranes, traversed the nucleus longitudinally from the acrosomal end to the basal nuclear fossa region. There were between three and six mitochondria, two types of centrioles (proximal and distal) in the midpiece and two vacuoles composed of lipid droplets. The flagellum (44.75+/-4.93 microm in length), originating from the centriolar apparatus, had a typical 9+2 eukaryotic flagellar organization. In addition, there was an extracellular cytoplasm canal between the cytoplasmic sheath and the flagellum. CONCLUSIONS: A principal components analysis explained the individual morphological variation fairly well. Of the total accumulated variance, 41.45% was accounted for by parameters related to the head and midpiece of the sperm and the length of the flagellum. Comparing the present study with previous studies of morphology of sturgeon spermatozoa, there were large inter- or intra-specific differences that could be valuable taxonomically.

The sperm of Hylodinae species (Anura, Leptodactylidae): ultrastructural characteristics and their relevance to interspecific taxonomic relationships.

Hylodinae leptodactylids (sensu Lynch 1971) form a group of diurnal frogs, which is hypothesized on the basis of morphological traits to be the closest relatives of the dendrobatid frogs. Our study describes ultrastructural characteristics of sperm from three hylodine species (Hylodes phyllodes, Crossodactylus sp. n. and Megaelosia massarti) to reassess the intergeneric relationships within the Hylodinae, as well as the supposed relationship between the Hylodinae and Dendrobatidae. The ultrastructure of the sperm is very similar among the three species and is indicative of its conserved nature within the Hylodinae. The structure of the acrosomal complex was very similar to that of other leptodactylid species, to most of the remaining species included in the Bufonoidea lineage, and also to that observed in the dendrobatid species examined so far. Since such a structure has been considered a plesiomorphic trait, it contributes little to our understanding of the relationships between the Hylodinae and Dendrobatidae. The flagellar apparatus of Crossodactylus sp. n. is very similar to that of most leptodactylids. The sperm of Megaelosia massarti and Hylodes phyllodes display a distinctive condition in their axial and juxtaxonemal fibers. This distinctive flagellar condition expands the already known variability in sperm structure within the Leptodactylidae.