Sperm Midpiece Research Articles

Sperm ultrastructure of Microhedyle remanei, an interstitial acochlidian gastropod with dermal fertilization

The ultrastructure of sperm of an acochlidian opisthobranch is described for the first time in detail, in the tiny, gonochoristic Microhedyle remanei (Microhedylidae) from Bermuda. Transmission electron microscopy (TEM) shows the spermatozoa of M. remanei sharing many plesiomorphic features with opisthobranch gastropods, such as having an apical spiral nucleus with a basal invagination filled with a bell-shaped centriolar derivative; there is a single glycogen helix embedded into matrix and paracrystalline material. Sperm of M. remanei are characterized by possessing a strongly helically coiled nucleus with up to five keels terminating into one very prominent and intertwined keel. The sperm midpiece shows the glycogen helix which is very densely arranged. This clearly differs from Hedylopsis ballantinei, a member of the related acochlidian family Hedylopsidae, where three glycogen helices with different lengths and a probably much shorter nucleus are present. This variation among acochlidian sperm may be phylogenetically relevant and may be related to special acochlidian reproductive features such as sperm transfer via hypodermic injection or dermal fertilization via spermatophores.

Abnormal Morphology of Spermatozoa in Cytochrome P450 17α‐hydroxylase/17, 20‐lyase (CYP17) Deficient Mice

Cytochrome P450 17alpha-hydroxylase/17, 20-lyase (CYP17) is crucial for cortisol and sex steroid biosynthesis. In a previous study we examined CYP17 function by generating mice with a targeted CYP17 deletion. We found that in addition to its role in steroid biosynthesis, CYP17 is present in germ cells. In the present study we examined the effect of CYP17 on sperm morphology. Disorganization of the sperm midpiece, small sperm mitochondria with reduced inner membranes and matrix, and irregular sperm shape were found to be associated with the CYP17 gene deletion. Treating the mice carrying the CYP17 deletion with testosterone did not alleviate the observed sperm phenotypes, suggesting that CYP17 acts in a testosterone-independent manner. These results suggest that CYP17, in addition to its role in androgen formation, is critical for proper mitochondrial architecture and sperm morphology and thus for sperm function and normal fertility.

Results of intracytoplasmic sperm injection in two infertile patients with abnormal organization of sperm mitochondrial sheaths and severe asthenoteratozoospermia

To report assisted reproduction technologies (ART) outcome and characterize severe mitochondrial sheath (MS) anomalies in two infertile asthenoteratozoospermic patients. Case reports. Private IVF clinic and academic research institution. Two infertile men with asthenoteratozoospermia. Intracytoplasmic sperm injection (ICSI) was performed in both cases. Clinical and laboratory evaluation were performed and spermatozoa studied by epifluorescence microscopy and transmission electron microscopy (TEM). Patient 1 had sperm with acute bendings at the level of the narrow midpieces. Mitochondria were either scarce or absent. Three ICSI embryos were transferred. A pregnancy was achieved followed by a miscarriage at the end of the first trimester. Patient 2 had sperm with very long MSs. The number of gyres was increased to more than 30. Two ICSI cycles were performed with good fertilization rates and embryo quality, but no pregnancy was achieved. MS defects were studied by phase-contrast, epifluorescence microscopy, and TEM that afforded a detailed view of the sperm midpiece and the topography of the whole flagellum. The results indicate that midpiece defects, while causing severe asthenozoospermia and lower fertilizing potential, may not necessarily represent negative prognostic factors in ART.

Intra‐individual variation in sperm tail length in murine rodents

AbstractIn eutherian mammals, there are marked interspecific differences in sperm head shape and tail length. In a few species, sperm head variability occurs but intra‐individual variation in sperm tail length has rarely been investigated or commented upon. Here, we ask the question: Do murine rodent species that have variable sperm head shapes exhibit greater intra‐individual variation in sperm midpiece and total tail lengths than closely related species where little, or no, sperm head variability occurs? From three separate lineages, we selected three pairs of murine rodents, one of which has monomorphic, and the other variable, sperm head shape. These were from southern Asia the bandicoot rats Bandicota bengalensis and Bandicota indica, from southern Africa the veld rats, Aethomys chrysophilus and Aethomys ineptus and from Australia the fawn hopping mouse Notomys cervinus and the spinifex hopping mouse Notomys alexis. Cauda epididymal sperm smears were prepared and sperm midpiece and total tail lengths were determined. A linear mixed‐effects model was used to estimate intra‐individual variance. The results showed that in all three species where there are variable sperm head shapes (B. indica, A. ineptus and N. alexis), statistically significantly greater intra‐individual variability of sperm midpiece and total tail lengths occurs (P<0.0001 in all cases). These species all have relatively smaller testes mass compared with the closely related species with monomorphic sperm populations. This suggests that depressed levels of intermale sperm competition may result in the occurrence of variability in not only the divergent sperm head shape but also in the length of the midpiece as well as that of the total length of the sperm tail.

Ultrastructural observations of cryoinjury in kangaroo spermatozoa

Macropod spermatozoa have proven difficult to cryopreserve such that empirical studies using high concentrations of glycerol and/or DSMO have resulted in only 10% post-thaw motility. We examined the ultrastructure and freeze-fracture of caput and cauda epididymal macropod spermatozoa at 35, 4 °C and following cryopreservation with and without 20% glycerol. The addition of 20% glycerol resulted in significant damage to the sperm plasma membrane and mitochondria compared to no glycerol at the same temperatures ( P < 0.05). Following cryopreservation, 20% glycerol significantly improved the preservation of the cauda epididymal sperm plasma membrane and mitochondria and reduced the incidence of axonemal damage and axonemal spaces. For caput epididymal spermatozoa, glycerol only improved the preservation of the plasma membrane following cryopreservation ( P < 0.05). Freeze fracture microscopy revealed a pattern of helically wound intramembranous particles in the plasma membrane over the fibre network of the mid piece of the sperm tail. The fibre network is an interconnecting cytoskeletal structure found underneath the plasma membrane of the kangaroo sperm midpiece and is thought to add rigidity to the proximal portion of the sperm tail. After thawing, the plasma membrane was damaged such that this structure was missing in patches, and the helical rows of particles were mal-aligned. On the principal piece, particles were arranged randomly at physiological temperatures; however, upon cooling to 4 °C with 20% glycerol, the particles become aggregated. Once rewarmed (35 °C), particles over the principal piece resumed their random organisation. This finding is further evidence of a reversible phase transition of the macropod sperm plasma membrane during cooling that is not associated with a loss of motility or membrane integrity.

Identification and localisation of SERCA 2 isoforms in mammalian sperm

Upon binding to the egg's zona pellucida, capacitated spermatozoa will undergo a calcium-dependent exocytotic event called acrosome reaction. During this process, Ca2+ depletion from internal stores is followed by an important rise in [Ca2+]i due to a massive Ca2+ influx. Previous reports have shown that the acrosome can act as a Ca2+ store and that depletion of thapsigargin-sensitive stores induces acrosome exocytosis in capacitated spermatozoa from different mammalian species. The effect of thapsigargin, a specific inhibitor of sarcoplasmic/endoplasmic reticulum Ca2+-ATPases (SERCAs), suggests the presence and implication of SERCA in the active Ca2+ uptake during mammalian sperm capacitation. Although the presence of a thapsigargin-sensitive Ca2+-ATPase has been debated, the aim of this study was to clearly determine whether SERCAs are present in mammalian spermatozoa. Using three different anti-SERCA 2 antibodies, mono- and polyclonal, which recognised the same protein, we successfully identified and localised SERCA 2 in human, mouse and bovine sperm. Western blot analysis suggests that more than one SERCA 2 splice variant are present, one detected in the fraction containing the outer acrosomal membranes and another one present in the subcellular fraction containing the sperm midpiece. These results were confirmed by indirect immunofluorescence where SERCA 2 was observed in the acrosome and midpiece regions of human sperm. SERCA 2 immunohistochemical studies on human testis and PCR-amplification of mRNA encoding for each SERCA 2 splice variant in spermatogenic cells support the presence of this Ca2+-ATPase family in mature spermatozoa. In this paper, we clearly demonstrate, for the first time, the presence of SERCA 2 in mammalian sperm.

Expression of various CDC25B isoforms in human spermatozoa

To explore the role of CDC25B protein in postmeiotic germ cells. In vitro experiment. University-based reproductive genetics laboratory. Fertile and infertile volunteers. Reverse transcription-polymerase chain reaction (RT-PCR), real-time RT-PCR, and immunostaining for CDC25B. Expression profiling of CDC25B in human spermatozoa. Four splicing variants (CDC25B1, B2, B3, and B4) are expressed in human spermatozoa. Immunofluorescence staining showed strong homogeneous staining in the midpiece of spermatozoa, and weak staining in the principal piece and cytosol of the head. The messenger RNA (mRNA) transcript level of CDC25B was increased in sperm samples of men with asthenospermia. The expression of CDC25B in different cellular compartments of human spermatozoa suggests that there are diverse noncell-cycle-related functions of CDC25B in terminally differentiated human germ cells.

Analysis of lipid peroxidation in human spermatozoa using BODIPY C11

Lipid peroxidation is known to be a major factor in the aetiology of defective sperm function. Although biochemical assays for this process exist, they are relatively insensitive and require large numbers of spermatozoa; a condition that cannot be met with many infertility specimens. Recently, a new approach for monitoring peroxidative damage has been introduced, involving the probe BODIPY (581/591) C(11), which readily incorporates into cells and undergoes a spectral emission shift when attacked by reactive oxygen metabolites. We have examined the applicability of this probe as an indicator of oxidative stress in human sperm populations using flow cytometry as an end point. The measurement of peroxidation with BODIPY C(11) demonstrated significant dependence on the presence of a ferrous ion promoter (P < 0.001), which was significantly enhanced in sperm recovered from low-density Percoll fractions (P < 0.05) and was particularly damaging to the sperm midpiece. Iron-induced radical formation was suppressed by ascorbate in a dose-dependent manner (P < 0.001) and could only be promoted by Fe(II) and Cu(II); nickel, zinc and Fe(III) were ineffective. The Fe(II)-promoted BODIPY C(11) signal was significantly correlated with the measurement of reactive oxygen species generation with dihydroethidium. We conclude that BODIPY C(11) is an extremely useful probe for indexing peroxidative damage in human spermatozoa.

Is the Distribution of Selenium and Zinc in the Sublocations of Spermatozoa Regulated?

In the sperm nuclei, of mammalian species selenium has been found only in the form of sperm nuclei glutathione peroxidase (snGPx) where it is most likely bound to the chromatin of spermatozoa. Over 80% of selenium in sperm is bound to the selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) in the midpiece of rat sperm. Zinc in sperm is mainly contained in the outer dense fiber (ODF) proteins of the flagella of mammalian spermatozoa. In the sperm nuclei, zinc is predominately located in the chromatin to the protamine proteins. In order to investigate if the insertion of zinc and selenium in sperm chromatin is regulated, the element concentrations were determined in equine spermatozoa and purified sperm nuclei. We found a significant positive correlation between the selenium concentration in equine spermatozoa and sperm nuclei. The same finding was obtained for the zinc concentration in spermatozoa and sperm nuclei. The results assume that the distribution of selenium and zinc in spermatozoa is regulated by cell signaling pathways and in this way determining the selenium and zinc amount in the chromatin of spermatozoa.

14 MORPHOLOGICAL AND FUNCTIONAL PARAMETERS OF ENDANGERED BERMEYA GOAT BREED SEMEN

The Bermeya goats are an endangered autochthonous breed distributed in the north of Spain. To ensure their genetic diversity and long-term survival, morphological and functional parameters of the semen must be known in order to preserve the current genetic stock in a germplasm bank. The aim of this work was to establish basic characteristics and post-thaw survival of Bermeya goat's semen obtained by electro-ejaculation, that is not well described in the literature. The semen was collected by electro-ejaculation from 7 bucks, 1 to 7 years old, twice per week, for 9 weeks (n = 83). Fresh semen was evaluated for volume (V), concentration (C), motility, morphology, functional integrity of the sperm (spz) membranes (hypoosmotic swelling test; HOST), and acrosome integrity rate (NAR). Individual and progressive sperm motility were analyzed by means of a computer-assisted sperm analysis system (CASA: SCA 2002�, Microptic, Barcelona, Spain) immediately after dilution with the extender at 37�C, and after cooling to 4�C; five fields per sample (diluted to 204 � 106 spz mL–1) were evaluated under a phase contrast microscope (100�). The NAR and morphological abnormalities of sperm head, midpiece, tail, and cytoplasmic droplets were determined by counting 100 spz under 1000�. For freezing, ejaculates with at least 80% motile spz were diluted at 32�C with Krebs-Ringer solution containing 20% egg yolk and 14% glycerol to a final concentration of 400 � 106 spz mL–1, cooled to 4�C for 90 min, aspirated into 0.25-mL plastic straws (IMV�, L'Aigle, France), frozen at 7 cm above liquid nitrogen (LN2) phase for 10 min, and then plunged into the LN2. Straws were thawed in a water bath at 39�C for 30 s for post-thaw survival analysis. Data were analyzed by the GLM and FREQ procedures (SAS; SAS Institute, Inc., Cary, NC, USA) and expressed as means � standard error. Fresh semen characteristics were: V = 1.7 � 0.1 mL; C = 2619 � 106 � 153 spz mL–1; total and progressive motility were 89.0 � 2.1% and 66.9 � 2.1%, respectively. Percentages of head abnormalities were 4.8 � 0.5; midpiece: 3.8 � 0.7; tail: 4.7 � 1.0; cytoplasmic droplets: 8.3 � 0.7; intact acrosome: 91.8 � 0.6; and membrane integrity: 49.2 � 2.1. At 4�C, the % of total motile spz was 62.6 � 1.6, and the post-thaw survival rate was 46.3 � 1.5. There were only individual differences (P &lt; 0.001) between bucks on sperm concentration, head abnormalities, and cytoplasmic droplets. In conclusion, our results indicate that semen quality is related to each individual animal and that electro-ejaculation allows collection of semen of satisfactory quality to use as fresh and for cryopreservation. However, the validity of our results for possible future sperm banking of endangered Bermeya goats semen must be confirmed by field trials.

The evolution of human reproduction: A primatological perspective

Successful reconstruction of any aspect of human evolution ideally requires broad-based comparisons with other primates, as recognition of general principles provides a more reliable foundation for inference. Indeed, in many cases it is necessary to conduct comparisons with other placental mammals to test interpretations. This review considers comparative evidence with respect to the following topics relating to human reproduction: (1) size of the testes, sperm, and baculum; (2) ovarian processes and mating cyclicity; (3) placentation and embryonic membranes; (4) gestation period and neonatal condition; (5) brain development in relation to reproduction; and (6) suckling and age at weaning. Relative testis size, the size of the sperm midpiece, and perhaps the absence of a baculum indicate that humans are adapted for a mating system in which sperm competition was not a major factor. Because sizes of mammalian gametes do not increase with body size, they are increasingly dwarfed by the size of the female reproductive tract as body size increases. The implications of this have yet to be explored. Primates have long ovarian cycles and humans show an average pattern. Menstruation is completely lacking in strepsirrhine primates, possibly weakly present in tarsiers and variably expressed in simians. The only other mammals reliably reported to show menstruation are bats. Three hypotheses have been proposed to explain the evolution of menstruation (eliminating sperm-borne pathogens; reducing the metabolic cost of a prepared uterine lining; occurrence as a side-effect of physiological changes), but no consensus has emerged. Copulation at times other than the periovulatory period is not unique to humans, and its occurrence during pregnancy is widespread among mammals. Although the human condition is extreme, extended copulation during the ovarian cycle is the norm among simian primates, in stark contrast to prosimians, in which mating is typically restricted to a few days when the female is in oestrus. The model of regular mid-cycle ovulation in simians is questionable. Gestation periods calculated on that basis show greater variability than in other mammals, and evidence from laboratory breeding colonies indicates that an extended mating period is matched by an extended period in which conception can occur. New evidence indicates that the noninvasive placentation found in strepsirrhine primates is not primitive after all. Furthermore, comparative studies reveal that such noninvasive placentation is not "inefficient". Evolution of highly invasive placentation in haplorhine primates is probably linked instead to immunological factors. Primates have relatively long gestation periods, and humans are average in this respect. However, there is evidence that humans show greater maternal investment during pregnancy in comparison with apes. Although the human neonate matches the typical precocial pattern of primates in most respects, a fetal pattern of brain growth continues for a year after birth, such that the human infant is "secondarily altricial" in terms of its dependence on parental care. Nevertheless, the "natural" lactation period of humans is probably about 3 years, fitting the expectation in comparison to other hominoids.

P-1002: The cause why apoptotic sperm have poor morphology profile as assessed by the sperm deformity index (SDI): A prospective study

Externalization of phosphatidylserine (PS) to the sperm outer membrane leaflet is considered to mark terminal apoptosis. Magnetic cell sorting (MACS) using paramagnetic annexin V-conjugated microbeads eliminates spermatozoa with externalized PS. The relationship between apoptosis and the sperm morphology has not been well characterized. The SDI is a novel quantitative expression of sperm morphological quality that has an enhanced predictive power and reproducibility. The aim of this study was to chart the shift in sperm morphology profile between the non-apoptotic and apoptotic sperm fractions. Prospective study. Semen specimens collected from 50 healthy donors were prepared by density gradient centrifugation (DGC) followed by MACS using annexin V-conjugated microbeads. The procedure delivers 2 sperm fractions: annexin-negative (non-apoptotic) and annexin-positive (apoptotic). Sperm morphology in the DGC preparations and the non-apoptotic and apoptotic sperm fractions was assessed using the Tygerberg’s strict criteria. A multiple entry technique was utilized to calculate the SDI scores and to assess the frequency of different sperm deformities in different sperm fractions. The SDI score was calculated by dividing the total number of deformities observed by the number of sperm randomly selected and evaluated irrespective of their morphological normality. Pair-wise comparisons were made using Wilcoxon’s signed ranked test. The non-apoptotic sperm fractions had significantly lower median SDI score compared to the apoptotic sperm fractions (p<0.0001) and to DGC preparations (p<0.0001). The non-apoptotic sperm fractions had significantly lower median percentage sperm with acrosomal defects and cytoplasmic droplets compared to the apoptotic sperm fractions (p<0.0001, p<0.03, respectively) and to DGC preparations (p<0.0001, p=0.0002, respectively). On the other hand, the median percentage of sperm with midpiece defects was significantly higher in the non-apoptotic and apoptotic sperm fractions compared to the DGC preparations (p=0.03, p<0.0001, respectively). The non-apoptotic sperm fractions and the DGC preparations had similar median percentages of sperm with tail defects but the percentage was significantly higher in the apoptotic sperm fractions. The median percentages of sperm with normal morphology using Tygerberg’s strict criteria were similar in the non-apoptotic sperm fractions and the DGC preparations, but significantly higher in the non-apoptotic sperm fractions compared to the apoptotic sperm fractions. The poor sperm morphology profile seen in the apoptotic sperm fractions may be partly due to the isolation of sperm with acrosomal damage and/or cytoplasmic droplet. It may also be partly due to a technique-induced damage to sperm midpiece and tail. The damage to the midpiece was significant even in the non-apoptotic sperm fractions. Under these circumstances the SDI is a more sensitive research tool than percentage of normal morphology in evaluating the shift in sperm morphology profile.

Mammalian sperm and oviducts are sexually selected: evidence for co‐evolution

AbstractOviduct length was measured in 48 species representing 33 genera of mammals in order to examine possible relationships between female morphology and the occurrence of sperm competition due to matings with multiple males. Multiple regression analyses revealed that residuals of oviduct length were positively correlated both with residuals of testes weight and with sperm midpiece volume in the genera and species studied. These correlations remained significant after application of comparative analysis of independent contrasts to control for possible phylogenetic biases in the data set. These results indicate that sexual selection (relating to sperm competition and cryptic female choice) has influenced co‐evolution of oviduct length, testes size and sperm morphology in mammals.

Reproductive patterns of stray male dogs in the tropics

Two studies were performed to determine annual reproductive patterns in stray male dogs in the tropics. In Study 1, four dogs housed individually outdoors were monitored once monthly for 12 months, including collection and assessment of semen, measurements of scrotal width, and determination of serum testosterone and prolactin concentrations. In Study 2 (conducted concurrently), a single blood sample (for serum testosterone concentration) was collected from 220 clinically healthy dogs, and after euthanasia, scrotal width and morphology of epididymal sperm were determined. The year was divided into three seasons: warm–dry (March to June); warm–humid (July to October) and fresh–humid (November to February). In Study 1, scrotal width, ejaculate volume, sperm count and motility were significantly lower during the fresh–humid season and sperm midpiece abnormalities were significantly more common during the warm–humid and fresh–humid seasons. Serum testosterone concentrations remained constant during the year. Prolactin concentrations did not differ significantly among seasons, but had a well-defined increase from the beginning of March to the end of August. In Study 2, sperm morphology was similar to in Study 1 and serum testosterone concentrations varied nonsignificantly during the year. Environmental factors, e.g. daylength may have influenced circannual changes in prolactin secretion. Seasonal variations in some reproductive tract and seminal traits were significant but of small magnitude and the percentage of morphologically normal sperm did not vary significantly among seasons. In conclusion, healthy male dogs constantly produced sperm and were apparently fertile throughout the year.

Failure of phospholipid hydroperoxide glutathione peroxidase expression in oligoasthenozoospermia and mutations in the PHGPx gene

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a selenoprotein belonging to the family of glutathione peroxidases. PHGPx has long been considered a major antioxidant that, in cooperation with vitamin E, protects biomembranes. To determine the expression pattern of PHGPx mRNA in human, quantitative RT-polymerase chain reaction (PCR) analyses using RNA from different embryonal and adult tissues were performed. A predominant expression was found in testes. In spermatozoa, PHGPx was found to be localized in the mid-piece of spermatozoa. We studied the relationship between spermatozoa PHGPx expression, mutations in PHGPx gene and human oligoasthenozoospermia, a defect in which both the number and the motility of spermatozoa are significantly below normal. Spermatozoa specimens from 45 infertile males were analysed for fertility-related parameters according to World Health Organisation and were classified as suffering from oligoasthenozoospermia. Two patients (4.44%) showed no expression of PHGPx and in nine patients (20.00%), a reduced expression of the enzyme was observed. DNA sequences of various regions of the PHGPx gene (coding, 5'flanking region and intron 1) from these patients and 58 fertile volunteers were analysed for mutations by PCR amplification and direct sequencing. Sequence data revealed no cause/effect relationship for any of the variants. From these data it can be concluded that oligoasthenozoospermia is associated with a decrease in the level of expression of PHGPx in the spermatozoa of some infertile men (24.44%), but is not linked to mutations in PHGPx gene.

Adenylate Kinases 1 and 2 Are Part of the Accessory Structures in the Mouse Sperm Flagellum1

Proper sperm function depends on adequate ATP levels. In the mammalian flagellum, ATP is generated in the midpiece by oxidative respiration and in the principal piece by glycolysis. In locations where ATP is rapidly utilized or produced, adenylate kinases (AKs) maintain a constant adenylate energy charge by interconverting stoichiometric amounts of ATP and AMP with two ADP molecules. We previously identified adenylate kinase 1 and 2 (AK1 and AK2) by mass spectrometry as part of a mouse SDS-insoluble flagellar preparation containing the accessory structures (fibrous sheath, outer dense fibers, and mitochondrial sheath). A germ cell-specific cDNA encoding AK1 was characterized and found to contain a truncated 3' UTR and a different 5' UTR compared to the somatic Ak1 mRNA; however, it encoded an identical protein. Ak1 mRNA was upregulated during late spermiogenesis, a time when the flagellum is being assembled. AK1 was first seen in condensing spermatids and was associated with the outer microtubular doublets and outer dense fibers of sperm. This localization would allow the interconversion of ATP and ADP between the fibrous sheath where ATP is produced by glycolysis and the axonemal dynein ATPases where ATP is consumed. Ak2 mRNA was expressed at relatively low levels throughout spermatogenesis, and the protein was localized to the mitochondrial sheath in the sperm midpiece. AK1 and AK2 in the flagellar accessory structures provide a mechanism to buffer the adenylate energy charge for sperm motility.

TSGA10 prevents nuclear localization of the hypoxia-inducible factor (HIF)-1α

The hypoxia-inducible factor (HIF)-1 is a transcriptional regulator of genes involved in oxygen homeostasis. We previously described testis-specific isoforms of HIF-1α (mHIF-1αI.1 and hHIF-1αTe). Using mHIF-1α exon I.1 knock-out mice we confirmed the specific expression of mHIF-1αI.1 in the sperm tail. A protein–protein interaction between HIF-1α and the testis specific gene antigen 10 (TSGA10) was identified by yeast two-hybrid screening. TSGA10 is expressed in testis but also in other organs and malignant tissues. Immunofluorescence analysis indicated that the C-terminal part of TSGA10 accumulates in the midpiece of spermatozoa, where it co-localizes with HIF-1α. HIF-1α nuclear localization and HIF-1 transcriptional activity were significantly affected by overexpressed TSGA10.

A review of spermatozoan morphology in Cetacea with new data for the genus Kogia

AbstractThere have been few studies on the morphology of spermatozoa of the Cetacea. Here we present a review of the existing published material and present new data for spermatozoa of Kogia breviceps, Kogia sima and Delphinus delphis. In contrast to the usual spiral arrangement of mitochondria in the midpiece of mammalian sperm, cetaceans exhibit a unique arrangement of spherical mitochondria arranged in tiers and columns along the midpiece, which is primitive in appearance. In addition, the midpiece of the cetacean spermatozoon is much shorter than that of other mammalian orders. Detailed knowledge of the morphology of the spermatozoa of cetaceans may help elucidate aspects of male reproduction and the fertilization process in this group.

Identification of agrin SN isoform and muscle-specific receptor tyrosine kinase in sperm

We previously demonstrated several nicotinic acetylcholine receptor (nAChR) subunits and associated proteins in human sperm. Here, we identified in sperm for the first time two additional nAChR-associated molecules: (1) agrin SNZ + in human sperm localized in the posterior post-acrosomal, neck, and flagellar mid-piece regions; (2) a low-molecular weight isoform of muscle-specific receptor tyrosine kinase in human and mouse sperm localized in the flagellar mid-piece of human sperm.

223 DESCRIPTION OF GENITALIA AND SPERM RECOVERED POSTMORTEM FROM A PYGMY SPERM WHALE, KOGIA BREVICEPS

A pygmy sperm whale (Kogia breviceps; adult male; 350 kg) was stranded and died on a beach near Cabo Bustos (Asturias, North of Spain) on March 12th, 2005. Finding specimens of this species is a rare event on Spanish shores, although this whale is not considered endangered. Postmortem examination was performed 24 h later. Genitalia (testicles and epididymides) were extracted. The postmortem report indicated that vas deferens and seminal glands seemed to contain an important amount of semen, which was not recovered. Refrigerated genitalia were send to our laboratory, arriving around 40 h postmortem. The refrigerated testicles were in poor physical condition upon arrival, indicating advanced tissue detoriation. The epididymides (very long) were not closely attached to the testicles, but were connected by a loose conjunctive membrane. We divided the epididymides into four regions that approximated the (1) caput, (2) mid-region, (3) corpus, and (4) cauda. Physical characteristics of the genitalia are described in Table 1. The left testicle was larger, and possibly more active, than the right one. A sperm sample was obtained from the cauda region after incising the tissue. Osmolality and pH of the sample were 428 mOsm/kg and 6.62, respectively (maybe due to tissue breakdown) and the sperm concentration was 1194 × 106/mL. Spermatozoa were immotile, even after diluting in buffered medium; it is possible that postmortem damage occurred quickly. However, using flow cytometry we determined that 57% of cauda spermatozoa had intact plasma membranes and acrosomes (determined by staining with 37 mmol/mL propidium iodide and 1 μg/mL PNA-FITC; Sigma, Madrid, Spain). Examination by phase contrast microscopy (×600) showed many spermatozoa with abnormal heads and bent midpieces and flagella, even in the cauda (13% and 21%, respectively). Sperm head morphometry was studied using DiffQuick staining and an automated analysis system (SCA2000; Microptic, Barcelona, Spain). Mean sperm head size was 3.71 ± 0.19 × 2.61 ± 0.12 μm in width and length, respectively. Computer analysis (AnalySiS-GmbH, Cologne, Germany) of phase contrast images revealed that the mean size of the sperm midpiece and flagellum were 3.44 ± 0.19 and 40.95 ± 2.02 μm, respectively. The information obtained after postmortem recovery of the testes and epididymis should be useful to future conservation efforts of the pygmy sperm whale and similar species. The rapid deterioration of the testicular tissue by 40 h postmortem was not expected since good quality sperm samples have been obtained at similar postmortem intervals in other species. Therefore, we recommend that postmortem sperm recovery should be accomplished as rapidly as possible in this species. Table 1. Genitalia measurements