bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate of sperm tail components after incorporation into the hamster egg
Authors: Hiraoka Jun‐Ichi , Hirao Yuki‐Hisa 
Published: February 2005

AbstractThe changes in the cytoplasmic organelles of sperm tail in golden hamster eggs fertilized in vivo were observed by electron microscopy. Eggs were obtained from oviducts of hamsters that had been superovulated and inseminated by injection of cauda epididymal spermatozoa into the uteri. In the egg cytoplasm 10 hours after insemination, some of the mitochondria of the spermatozoon midpiece had begun to swell, and a number of multivesicular bodies were observed surrounding the midpiece. The fibrous sheath of the principal piece quickly disappeared prior to the first cleavage, whereas the axoneme and outer dense fibers were unaltered.During the two‐cell stage, numerous multivesicular bodies gathered around the midpiece and fused with the mitochondria. The heterophagic vacuoles thus formed then gradually separated from the axial fibers. The outer dense fibers were disarranged and partially torn into small segments; then they seemed to dissociate into substructural granular components. The axonemal microtubules had begun to swell but were still present in the two blastomeres. It is indicated from these observations that at least the mitochondria of the tail constituents carried into the oocyte are digested into small molecular elements by the multivesicular bodies and are possibly distributed as nutrients for the blastomeres during the early stage of development.
Epididymal sperm profiles in young adult, middle‐aged, and testosterone‐supplemented old rats
Authors: Taylor George T. , Weiss Jürgen , Pitha Josef 
Published: February 2005

AbstractBoth ejaculated semen and epididymal contents from an individual male contain sperm that differ in various physicochemical characteristics. An experiment is reported in which epididymides from rats 5–24 months old were subjected to density gradient centrifugation to separate gametes of different stages of maturity. The research was designed to examine typical changes in “profiles” of sperm maturity during the reproductive lifetime of rats. Also, testosterone complexed with cyclodextrin that mimics the episodic release of the endogenous hormone was used to supplement the decreased circulating titers of some of the old males. Results revealed clear ontogenetic patterns of gradually decreasing reproductive competence as measured by absolute numbers of sperm, circulating levels of testosterone, and various other physiological markers of fertility. Sperm profiles also revealed age‐specific changes with a shift toward progressively more mature, perhaps senile, gametes that begins at middle age. Testosterone supplementation (400 μg/kg b.w./day for 30 days) failed to restore sperm numbers or other measures of physiology in the old males, but the steroid modified sperm profiles to approximate more closely the profiles characteristic of young adult males than either untreated middle‐aged or old males. The data were interpreted as suggesting that epididymal sperm profiles clearly identify males of different ages, and that the aging epididymis retains its capacity to respond to manipulations that modify the endocrine milieu.
Egg‐penetration ability and structural properties of human sperm prepared by Percoll‐gradient centrifugation
Authors: Tanphaichitr N. , Millette C. F. , Agulnick A. , Fitzgerald L. M. 
Published: February 2005

AbstractHuman sperm with a high zona‐free hamster egg‐penetration ability were obtained by centrifuging freshly ejaculated sperm through a discontinuous two‐step (47% and 90%) Percoll gradient at 600g at room temperature for 30 min. Highly motile sperm with good penetration ability were recovered in the pellet fraction (Per‐sperm), whereas those with low penetration ability were in the gradient interface. The increased penetration ability of Per‐sperm, as compared to sperm capacitated by other methods such as a single‐tube swim‐up or multiple‐tube swim‐up preparation, was not due to an increased proportion of acrosome reacted sperm. Rather, transmission electron microscopy indicated that Per‐sperm were devoid of coating envelopes, which were present around both the head and tail regions of noncapacitated and single‐tube swim‐up sperm. Changes to the surface of Per‐sperm were demonstrated by their decreased interaction with UEA I lectin, which binds specifically to fucose residues. Removal of the coating envelopes as well as other changes on the sperm surface may lead to an enhanced binding of Per‐sperm to the oocyte. In addition, 99% of Per‐sperm contained chromatin that was fully condensed. By contrast, about 15% of swim‐up sperm still possessed incompletely condensed chromatin. With a higher penetration ability, “clean” appearance, and homogeneity of condensed chromatin, Per‐sperm are recommended for insemination and studies of human sperm capacitation.
Attempted sexing of bovine spermatozoa by fractionation on a Percoll density gradient
Authors: Upreti G. C. , Riches P. C. , Johnson L. A. 
Published: February 2005

AbstractBovine spermatozoa were fractionated on Percoll density gradients into two major subpopulations of motile spermatozoa and a minor fraction containing mostly nonmotile spermatozoa with abnormal morphology. Fractionation required the addition of bovine serum albumin and a continuous Percoll gradient buffered with sodium bicarbonate. It is postulated that, under suitable ionic conditions, the binding of bovine serum albumin to spermatozoa amplifies subtle differences between subpopulations. These studies were directed toward separating Y‐ and X‐bearing spermatozoa. However, when the subpopulations were evaluated by flow cytometry, their Y:X ratios were similar to that of an unfractionated control.
Xenopus spermatozoon: Correlation between shape and motility
Authors: Bernardini Giovanni , Andrietti Francesco , Camatini Marina , Cosson Marie‐Paule 
Published: February 2005

AbstractXenopus spermatozoa have a characteristic corkscrew‐shaped head and a flagellum with a conventional “9 + 2” structure (Bernardini et al.: J Ultrastruct Md Struct Res: 94:188–194). They are motile in water and media of low osmolarities, but not in media of osmolarities higher than 200 mosm/liter, regardless of the ionic composition. External calcium and pH are not involved in the inhibition of sperm movement at high osmolarities.The duration of sperm motion was less than 10 min, and both flagellar beat frequencies and sperm velocities declined progressively. However, in demembranated and reactivated tails, flagellar beating was sustained for longer times. Flagella propagated three‐dimensional waves that induced a spinning motion of the whole spermatozoon. This pattern of movement is not dependent on the shape of the sperm head, since isolated, reactivated flagella exhibited three‐dimensional waves.
Effect of follicle somatic cells during pig oocyte maturation on egg penetrability and male pronucleus formation
Authors: Mattioli Mauro , Galeati Giovanna , Seren Eraldo 
Published: February 2005

AbstractIn order to investigate the effect of the somatic cells of the follicle on the preparation of the oocyte for fertilization three experiments were carried out. In the first, pig oocytes, cultured for 46 h in the presence of extroverted follicles (follicle oocytes) or surrounded by the cumulus (cumulus oocytes), were exposed to sperm in an in vitro fertilization system. Follicle oocytes showed a higher rate of fertilization than that recorded in cumulus oocytes (80% vs. 47%). In addition, significantly more sperm penetrated into the ooplasm of follicular oocytes (3.77/egg) than into that of cumulus oocytes (1.42/egg). To investigate the reason for the observed fertilization difference zona‐free oocytes were studied in the second experiment. Significantly more spermatozoa were recorded in the ooplasm of follicle oocytes than in that of cumulus oocytes, thus suggesting that the effect of the follicle on fertilizability may partly depend on an action on the plasma membrane of the oocyte. A further effect of the follicular tissue was on cytoplasmic maturation: only follicular oocytes were capable of consistently promoting male pronucleus formation. In cumulus oocytes, sperm that entered the cytoplasm remained in a condensed form near the female pronucleus. In the third experiment cumulus oocytes and denuded oocytes were matured in medium that had been previously used to mature follicle oocytes. This conditioned medium was alone able to affect sperm penetration and male pronucleus formation in cumulus oocytes, but it did not exert any influence on denuded oocytes. This suggests that the observed effect of the follicle is mediated by soluble factors that, however, cannot influence the oocyte without some direct cell‐oocyte contact.
Studies of stallion sperm survival: Preservation of progressive motility of stallion spermatozoa by low ionic strength media
Authors: Bize Isabel , Driscoll David M. 
Published: February 2005

AbstractPreservation of stallion sperm forward motility was studied using a video recording system in semen diluted with media of different ionic strength and sodium content. After 8 hr of incubation at room temperature, semen diluted in a low ionic strength media containing sucrose displayed 65±9% motility with 68±3% of the motile sperm showing forward motility (diameter of head trajectory ≥ 80 μm). In contrast, sperm populations diluted and incubated with a normal ionic strength media containing sodium had 56±7% motile sperm of which only 36±7% displayed forward progression. Replacement of the sodium ion in the normal ionic strength media by a different cation (choline) produced results similar to those of the media containing high sodium concentration. These results indicate that the preservation of stallion sperm progressive motility is highly dependent on the ionic strength of the media. Membrane depolarization caused by the replacement of ions by noncharged particles in the sperm's external medium might be responsible for the sustained coordination of the flagellar movements.
Human sperm injection into the perivitelline space (SI‐PVS) of hamster oocytes: Effect of sperm pretreatment by calcium‐ionophore A23187 and freezing‐thawing on the penetration rate and polyspermy
Authors: Lassalle B. , Testart J. 
Published: February 2005

AbstractCalcium‐ionophore A23187 and freezing‐thawing were used as sperm treatments before human sperm injection into the perivitelline space (SI‐PVS) of hamster oocytes. The penetration rate (PR) was higher when SI‐PVS was performed with calcium‐ionophore‐treated (28%) or frozen‐thawed (51%) sperm than with untreated sperm (8%). Optimal PR occurred when five calcium‐ionophore‐treated (57%) or frozen‐thawed (71%) sperm were injected under the zona pellucida. When the sperm:egg ratio was 1:1, PR was higher for calcium‐ionophore‐treated (18.5%) or frozen‐thawed (27.8%) sperm than for untreated sperm (0.0%). Calcium‐ionophore sperm treatment had no effect on the polyspermic oocyte rate (POR) or the mean number of swollen sperm nuclei per penetrated oocyte (Pd) or per injected sperm (SR). This may result from premature oocyte activation induced by Ca‐ionophore. However, POR was higher with frozen‐thawed (74%) than with untreated (50%) or Ca‐ionophore‐treated (50%) sperm. Whatever the sperm treatment, there was a trend toward a lower SR as the number of injected sperm increased. Cytoplasmic regulation of polyspermy in the hamster oocyte is discussed.
Low molecular weight factor in bovine caudal epididymal fluid that stimulates calcium uptake in caput spermatozoa
Authors: Vijayaraghavan Srinivasan , Hoskins Dale D. 
Published: February 2005

AbstractSecretions from the mammalian epididymis contain proteins that bind to developing sperm and are presumed to play a role in sperm maturation. The biochemical functions in sperm of most of these proteins are not known. In this report we describe the presence of a low molecular weight compound in bovine caudal epididymal luminal fluid (CF) that has a potent stimulatory effect on calcium (45Ca2+) uptake in immature caput epididymal spermatozoa. The studies were initially undertaken to characterize the effect of the protein caltrin, present in bovine seminal plasma (BSP), on calcium uptake into caput spermatozoa. Caltrin is known to block calcium influx into mature bovine sperm. Unexpectedly, the kinetics of calcium uptake into caput sperm showed a biphasic response when treated with BSP, namely, a stimulation of uptake at 1 to 5 min and inhibition of uptake after this time. Since caudal sperm do not show this biphasic response, we reasoned that BSP contained a factor derived from CF that must interact with developing sperm before the binding of caltrin to sperm can prevent further calcium uptake. We first demonstrated that preincubation of caput sperm with CF eliminated the biphasic calcium uptake effect induced in caput sperm by BSP and that caudal fluid alone had a potent stimulatory effect on calcium uptake in caput sperm. Half‐maximal stimulation (fivefold over control) occurred at a caudal fluid protein concentration of 0.27 mg/ml. Partial purification of the factor indicates that it is of low molecular weight (MW ∼ 1,000), but further chemical characterization has not been carried out and its epididymal site of origin is not known. The results indicate that the regulation of intracellular calcium levels in sperm differs in immature and mature bovine sperm in that an epididymal factor promotes calcium uptake during epididymal maturation, and the seminal fluid protein caltrin prevents it at ejaculation.
Cholesterol efflux from bovine sperm: II. Effect of reducing sperm cholesterol on penetration of zona‐free hamster and in vitro matured bovine ova
Authors: Ehrenwald Eduardo , Parks John E. , Foote Robert H. 
Published: February 2005

AbstractSeveral reports have indicated that sperm capacitation includes loss of membrane cholesterol (Chol) with a concomitant decrease in the Chol‐to‐phospholipid (PL) ratio. Methods were developed for quantifiable removal of bovine sperm Chol, which predisposed sperm to induction of the acrosome reaction upon addition of lysophosphatidylcholine (LPC). The objective of this study was to evaluate the effect of Chol removal from bovine sperm on penetration of zona‐free hamster and intact bovine ova in vitro. Washed ejaculated bovine sperm were incubated (2 h, 39°C) in a modified Tyrode's solution (TALP) containing (1) Chol‐free liposomes (—Chol, 50 × 106 sperm and 600 nmol phospholipid/ml); (2) liposomes containing 30 mol% Chol (+ Chol, 2 × 108 sperm and 300 nmol total lipid/ml); or (3) no liposomes (Control). We have previously shown that net Chol efflux from sperm is 31% of the total sperm Chol with —Chol liposomes and less than 1% with control media. Sperm were then washed twice and challenged with LPC bound to bovine serum albumin (BSA) using celite as a carrier. Treated sperm (25 × 106) were incubated immediately with either zona‐free hamster ova (HO) or in vitro matured bovine ova (BO) in 50‐μl droplets of TALP under medical fluid in an atmosphere of 5% CO2 in air (3 h, 39°C). Ova were fixed in ethanol:acetic acid, stained with 1% orcein, and examined. Percent penetration (%P) of HO (X ± SEM) for 30 and 40 μg of LPC/mg BSA was 59.4 ± 5.3 and 82.9 ± 5.4; 38.5 ± 5.6 and 52.3 ± 4.7; and 16.0 ± 4.6; and 23.2 ± 5.6 for —Chol, Control, and + Chol treatments, respectively (n = 3). %P of BO (X ± SEM) for 30, 35, and 40 μg of LPC/mg BSA was 43.3 ± 5.4, 70.7 ± 7.5, and 81.5 ± 5.1 for —Chol and 16.4 ± 6.9, 36.2 ± 6.9, and 44.2 ± 8.6 for Control treatments, respectively (n = 3). In a second set of experiments %P of BO (X ± SEM) was 63.6 ± 6.8, 31.8 ± 4.9, and 10.5 ± 3.4 for —Chol, Control, and +Chol treatments, respectively, when 40 μg LPC/mg BSA was added (n = 2). %P and the number of sperm per fertilized ovum were consistently higher for the —Chol treatment for both HO and BO (P < .01). These results demonstrate that Chol removal from bovine sperm facilitates penetration of ova in vitro suggesting a potential role in bovine sperm capacitation.
Filipin‐labelled complexes are polarized in their distribution in the cytoplasm of meiotically mature mouse eggs
Authors: Allworth Ann , Ziomek Carol A. 
Published: February 2005

AbstractUnfertilized (germinal vesicle [GV] stage, superovulated and naturally ovulated) and fertilized mouse eggs were treated with the polyene antibiotic filipin, which complexes with unesterified sterols; specimens were observed by fluorescence microscopy and scanning electron microscopy (SEM).In all oocytes examined, filipin fluorescence was localized to the plasma membrane and to subcellular structures of various sizes. In the unfertilized oocyte, polarity was observed both in the plasma membrane stain and in the pattern formed by the subcellular structures. SEM of filipin‐treated oocytes had several characteristic features including a specific distribution of heterogeneous microvilli that appears to have a spatial relationship with the fluorescent pattern of the filipin‐positive subcellular structures.In GV stage and fertilized eggs the filipin‐positive subcellular structures were associated with the germinal vesicle and in fertilized eggs they were associated with the site of polar body abstriction.
Changes of elemental concentrations around and on the surface of fowl sperm membrane during maturation in the male reproductive tract and after in vitro storage
Authors: Ashizawa Koji , Ozawa Yoko , Okauchi Keizo 
Published: February 2005

AbstractX‐ray microprobe analysis was performed to investigate the changes of elemental concentrations around or on the membrane of the head, midpiece, and principal piece regions of individual fowl spermatozoa during maturation in the male reproductive tract and after storage in vitro at 4°C. The pattern of change of elemental concentrations during maturation and postejaculation was, in general, similar in the three different subcellular regions; i.e., concentrations of sodium, potassium, chlorine, and calcium decreased gradually during sperm passage through the male reproductive tract and after storage. Phosphorus concentration remained almost constant in the male tract and decreased gradually after storage. In contrast, magnesium, zinc, and copper concentrations showed an interesting pattern: concentrations increased significantly during maturation to a maximum at ejaculation and decreased again after storage. The ratios of sodium to potassium in the midpiece region showed patterns similar to those of magnesium, zinc, and copper concentrations.
Sperm entry into zona‐free oocytes in the hamster oviduct: Implications for the mechanisms of acrosome reaction induction
Authors: Cuasnicu Patricia S. , Bedford J. M. 
Published: February 2005

AbstractThe possible importance of the zona pellucida for induction of the acrosome reaction (AR) and establishment of sperm/egg associations in the fallopian tube was investigated by instilling zona‐free eggs into the oviductal ampulla of hamsters that had been inseminated with epididymal spermatozoa 6–7 hours previously. The eggs were recovered only 60–90 minutes later because of increasing difficulty with time of collecting zona‐free eggs from the oviduct. In the zona‐free group, 41 (4%) of 1,101 transferred eggs were recovered, of which 20% contained spermatozoa with decondensing nuclei (mean 4.4/egg). A similar (22%) fertilization rate (mean 3.2 spermatozoa/egg) was found among intact (control) eggs recovered after instillation into the contralateral oviduct.Mammalian spermatozoa are not incorporated even into zona‐free eggs before AR occurs. These results thus demonstrate that an AR in functional hamster spermatozoa in vivo and establishment of sperm/egg associations in vivo require no interaction with the zona pellucida nor with other products of ovulation.
Fertilization envelope assembly in sea urchin eggs inseminated in Cl− deficient sea water: I. Morphological effects
Authors: Lynn John W. , Goddard Russell L. , Glas Patricia , Green Jeffrey D. 
Published: February 2005

AbstractElevation and hardening of the fertilization envelope (FE) occur within 15 min following insemination of the sea urchin egg. When chloride ions were replaced in the media with various anion substitutes, including methyl sulfonate, nitrates, bromide, and isethionate, the fertilization envelope failed to harden and collapsed back to the surface of the egg of Lytechinus variegatus, L. pictus, and Strongylocentrotus purpuratus. At the light microscopy level, the collapse of the envelope was accompanied by a decrease in birefringence, compared with controls. When examined with electron microscopy, the FEs of eggs inseminated in reduced Cl− solutions failed to transform from an amorphous layer into the more robust laminar structure observed around eggs incubated in normal sea water. Furthermore, in the case of S. purpuratus, the I‐T transformation of the FE did not occur. When transfer of the inseminated eggs from the Cl−‐deficient sea water to normal sea water was carried out before 10 min elapsed, the envelope did not collapse, and the birefringence of the envelope was similar to that of controls. Partial envelope collapse was also observed in a dose‐dependent manner, varying with the concentration of the Cl− in the sea water solution. The results suggest that lack of Cl− in the media may interfere with proper fertilization envelope assembly. Possible mechanisms, including proper incorporation of the cortical granule exudate into the nascent envelope structure, are discussed.
Sperm‐engulfing response of sea urchin egg surfaces inseminated with acrosome‐reacted starfish sperm
Authors: Kyozuka Keiichiro , Osanai Kenzi 
Published: February 2005

AbstractSperm‐egg interaction was examined in two interclass combinations of sea urchin (Strongylocentrotus nudus and Hemicentrotus pulcherrimus) eggs and starfish (Asterina pectinifera and Asterias amurensis) sperm. Cross‐fertilization was unsuccessful between these combinations. When the vitelline coat‐free sea urchin eggs were mixed with acrosome‐reacted starfish sperm, the elongated microvilli on the egg surface wrapped the sperm head. This sperm‐engulfing response observed on the denuded egg surface was induced only in sperm immediately after initiation of the acrosome reaction. Further fertilization events, such as gamete membrane fusion or discharge of cortical granules, did not proceed. These observations suggest that acrosome‐reacted sperm can induce a local response on the heterologous egg surface, that is independent of gamete membrane fusion and egg activation.
Different outcomes of sperm competition in right and left sides of the female reproductive tract revealed by thymidine‐3H‐labeled spermatozoa in the rat
Authors: Špinka M. 
Published: February 2005

AbstractWe attempted to record directly the results of sperm competition between two male rats in samples from female reproductive tracts. Gametes of 7 male rats were labeled in vivo by repeated injections of thymidine‐6‐3H. 33 females were mated successively with one of the injected males and with a noninjected male, or vice versa. Samples of the resulting sperm mixtures were recovered from both the uterine horns and the oviducts of the females. Pure samples of the injected males' sperm were obtained from uterine horns of females mated solely to them. Smears of samples were evaluated autoradiographically. Except for one male, the injections resulted in a broad peak of sperm labeling with maximum intensity on days 56–58 postinjection. This labeling enabled the assessing of contribution of either male to uterine and tubal sperm in the competitive matings. The injections did not influence competitive ability of male gametes in terms of sperm transport to horns or oviducts. The outcomes of sperm competition were significantly different in the right and left sides in most female subjects. Nevertheless, the outcomes were usually similar in a horn and a tube on the same side of the body. In vivo sperm labeling appears to be a useful method in the study of rodent sperm competition.