bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in the stainability and sulfhydryl level in the sperm nucleus during sperm‐oocyte interaction in mice
Authors: Miller Margaret A. , Masui Yoshio 
Published: February 2005

AbstractDuring maturation in the epididymis, mouse sperm nuclei become difficult to stain with Giemsa and its component basic dyes. Mature sperm from the cauda epididymis can be stained only after DTT treatment. Stainable sperm such as those from the testis accumulate 3H NEM when examined by autoradiography, while unstainable sperm do not, indicating a close correlation between the basic dye binding capacity and SH levels in the sperm nuclei. During insemination of zonafree ovarian oocytes with a germinal vesicle (GV), mature sperm nuclei become stainable and capable of binding with 3H NEM. At the same time, sperm have established pronase‐resistant contact with the oocyte. Similarly, sperm nuclei become stainable during fertilization when the sperm attachment to the egg becomes pronase resistant. However, these changes occur before sperm chromatin decondensation begins. Therefore, it is suggested that S‐S bonds in sperm nucleoproteins are reduced when the sperm establish a stable contact with the egg plasma membrane, thus reversing sperm maturational changes. The reduction of S‐S bonds may be a prerequisite for sperm chromatin decondensation.
Chromatin transitions in the fertilizing sperm nucleus of the sea urchin, strongylocentrotus purpuratus
Authors: Kunkle Mel 
Published: February 2005

AbstractElectron microscopic analysis of fertilization in the sea urchin, Strongylocentrotus purpuratus, has been carried out in an effort to establish the sequence of events involving dispersion of the paternal chromatin. Subsequent to loss of the nuclear envelope the condensed sperm chromatin begins to disperse under the influence of egg cytoplasmic factors. However, this process does not proceed at a uniform rate as is observed in other species examined to date. Portions of the paternal genome rapidly transform into dispersed chromatin while other adjacent regions disperse at a reduced rate. This variation in the time sequence of dissociation of the paternally derived chromosomes results in a reticulum of electron lucent and electron dense chromatin within the developing male pronucleus. As the paternally derived chromatin is dispersing and migrating centrad, membranous vesicles of maternal origin become aligned along the peripheral aspect of the chromatin. Deposition of a continuous bilaminar nuclear envelope around the dispersing sperm chromatin results in the formation of the definitive male pronucleus. At the time the male pronucleus is formed the paternally derived chromosomes have not completely dispersed and are visualized as a reticulum of condensed and dispersed chromatin. These results indicate that not all the paternally derived chromatin is modified in the same manner during pronuclear development.
The structure and formation of rolled and crested bull spermatozoa
Authors: Cran D. G. , Dott H. M. , Wilmington J. W. 
Published: February 2005

AbstractThe ejaculate of a Friesian bull contained three abnormalities: rolled, crested, and knobbed spermatozoa. The rolled form had marked lateral curvature of the head, occasionally forming a complete tube. All three forms were of testicular origin and it is likely that the first two were developmentally related.
Bioelectric responses at fertilization: Separation of the events associated with insemination from those due to the cortical reaction in sea urchin, Lytechinus variegatus
Authors: Hülser Dieter , Schatten Gerald 
Published: February 2005

AbstractThe bioelectric responses at fertilization of the sea urchin Lytechinus variegatus are a complex series of membrane potential and resistance changes that occur concomitant with gamete fusion, ionic fluxes, and the cortical granule discharge. This work attempts to separate the electrical effects of sperm‐egg interactions from those of the cortical reactions. Two approaches were taken to discern the electrical events associated with insemination, distinct from cortical granule discharge: (1) fertilization of eggs treated with 3% urethane, 10 mM procaine, or 10 mM nicotine, to prevent the cortical reaction and (2) refertilization of fertilized eggs (denuded with 1 mM aminotriazole containing 1 mg/ml soybean trypsin inhibitor). Cortical granule discharge in the absence of sperm incorporation was investigated by artificial activation with 5 μM A23187 or by fertilization in the presence of 10 μM cytochalasin D, which prevents incorporation.These results are consistent with a model in which the sperm‐egg interaction triggers both a rapid (50–400 msec), but minor (≅10 mV), electrical transient that leads to an action potential and then both the Na+‐dependent fast block to polyspermy and the late block resulting from the secretion of the cortical granules.
Synthetic peptides are not chemoattractants for bull sperm
Authors: Miller Richard L. 
Published: February 2005

AbstractRecent claims that bull sperm display chemotaxis to synthetic peptides known to be chemotactically active for neutrophils are not based on direct observation of sperm behavior. When these observations are made, no change in sperm motility or direction is seen. The supposed chemoattractant effect is probably based on disruption by the peptides of the sperm acrosome, resulting in increased sperm adhesion to the glass surface inside the pipette containing the supposed chemoattractive peptide.
Acquisition of zona binding by ram spermatozoa during epididymal passage, as revealed by interaction with rat oocytes
Authors: Fournier‐Delpech S. , Courtens J. L. , Pisselet C. L. , Delaleu B. , Courot M. 
Published: February 2005

AbstractTo assess the ability of ram spermatozoa to bind to oocytes, spermatozoa (2.5–200 × 106/500μ1) taken from the rete testis, or from various regions of the epididymis (head, body, and tail) were mixed with cumulus‐free heterologous oocytes obtained from immature superovulated rats. After incubation for 30–45 min in Parker 199 Hepes medium at 35°C, testicular spermatozoa were unable to bind to the zona at any of the concentrations used. However, spermatozoa from the middle body of the epididymus were able to bind to the zona and this binding reached a maximum in the distal body and in the tail of the epididymis. The spermatozoa were bound by their heads. Electron microscopy showed that the plasma membrane and the acrosome of the bound sperm remained intact, without any sign of an acrosome reaction.
Preimplantation losses of zygotes in superovulated immature rats
Authors: Sherman D. , Nelken Michal , Kraicer P. F. 
Published: February 2005

AbstractThe development of zygotes in immature, superovulated, and adult female rats was followed by flushing their oviducts and uteri on each of the days L1–L4 (LO is day of sperm finding). Superovulated rats showed a 3.6 times greater rate of preimplantation losses. The loss occurred between L1 and L2 in immatures and was restricted to some of the females; in matures the loss was between L3 and L4. In the immatures some zygotes were already in the uterus on L2. The loss of zygotes in the immature rats is attributed to accelerated transport leading to expulsion as well as lysis of some zygotes within the tract. These latter may be the zygotes identified as morphologicaly abnormal. It is speculated that PMSG may force the ovulation of unfit oocytes.
Postovulatory aging of human ova: I. Light microscopic observations
Authors: Ortiz M. E. , Salvatierra A. M. , López J. , Fernandéz E. , Croxatto H. B. 
Published: February 2005

AbstractThe morphologic changes undergone by the human secondary oocyte following ovulation were assessed by light microscopy in 57 specimens recovered from the Fallopian tube and endometrial cavity between 24 and 144 hr after the luteinizing hormone peak in plasma. Ovarecovered shortly after ovulation were surrounded by a large cumulus mass comprising approximately 20,000 follicular cells. Whenever it was possible to perform a detailed observation of the perivitelline space in these ova, the presence of a polar body was recognized. The oocyte usually occupied an excentric position within the cumulus. Ovum denudation appeared to proceed by breakdown of the cumulus into fragments and release of the oocyte with a small number of cells attached to the zona. As a consequence of this process the oocyte surrounded by a few layers of cells frequently coexisted with large fragments of the cumulus. Progress of ovum denudation was time dependent and proceeded at a relatively slow pace. Some uterine ova still had cells attached to the zona. At 96 hr after the LH peak 40% of the ova underwent fragmentation of the cytoplasm giving rise to anucleated pieces of varying sizes. The dimensions of the zona pellucida and ooplasm presented wide individual variations as well as some time related changes. The mean external diameter of the zona ± SD of 43 ova was 161.6 ± 14.6 μm.The occurrence of denudation and cytoplasmic fragmentation were more clearly related to the postovulatory age of the ovum than to the site of recovery. The rate of denudation of human oocytes seems to proceed at a much lower speed in comparison with small mammals currently used as laboratory animals.
Insulin induction of meiosis of rana pipiens oocytes: Relation to endogenous progesterone
Authors: Lessman Charles A. , Schuetz Allen W. 
Published: February 2005

AbstractThe follicle wall was previously shown to be involved in insulin induction of oocyte maturation in Rana pipiens ovarian follicles. Steroidogenic involvement in insulin induction of maturation was investigated following development of a radioimmunoassay (RIA) for progesterone to measure endogenous progesterone associated with in vitro incubates. Insulin and frog pituitary homogenate (FPH) were both found to elevate progesterone levels significantly in these incubates. FPH was more effective in elevating progesterone levels than insulin and caused progesterone increase of about 2 orders of magnitude greater than insulin. Removal of the follicle wall eliminated the steroidogenic effects of insulin. Considerable interanimal variation was observed in the ability of insulin to induce oocyte germinal vesicle breakdown (GVBD) in intact follicles. The hypothesis was proposed that differences in endogenous progesterone might explain this variation. To test this hypothesis, an experiment was carried out in which hormone production and follicular sensitivity to insulin were simultaneously determined in follicles obtained from the same animals. Results of the experiment show that the ability of insulin to induce GVBD, as indicated by the effective concentration needed for 50% response (ED50), was strongly correlated with the levels of endogenous progesterone as measured by RIA. The results provide direct evidence that insulin's action on the follicle wall involves steroid production. It was thus concluded that increased endogenous progesterone facilitates GVBD induction by insulin. It is unclear how the two hormones interact to produce an enhanced effect, but interactions at the receptor or postreceptor level may be involved. This follicle system may provide important insights into the mode of action and interaction of these two important hormones.
Preimplantation embryo development in the mouse: Role of histidine decarboxylase
Authors: Hudgins Louanne , Mukerjee S. , Dey S. K. 
Published: February 2005

AbstractThe present study determines the effect of a specific and an irreversible inhibitor of histidine decarboxylase (HDC), α‐fluoromethylhistidine (α‐FMH) on the mouse preimplantation embryo development in vitro. The embryo culture technique was used to assess the effect of α‐FMH. Embryos recovered at 0800–0900 hr (AM) on day 3 of pregnancy were 4–8 cells, whereas those recovered at 1600–1630 hr were mostly 8‐cell compacted embryos. Of the day 3‐AM embryos, 81.3 ± 4.3% developed to blastocysts within 48 hr when cultured in the medium alone, but addition of α‐FMH (0.19 or 0.38 mM) drastically reduced the blastocyst formation to 26.6 ± 7 or 16.8 ± 4.3%. Most of them were arrested before the compaction stage. Addition of L‐histidine, the substrate for HDC, did not alter the inhibition of blastocyst formation in the presence of α‐FMH (37.2 ± 10.9%). Of the day 3‐PM embryos, 99.3 ± 0.7% developed to blastocyst stage when cultured in the medium alone and addition of α‐FMH (0.19 or 0.38 mM) did not affect the embryo development (92.1 ± 4.3 or 81.9 ± 9.9% developed to blastocysts). The birth of healthy young following transfer of these blastocysts into pseudopregnant mice indicates normal development of the embryos under this condition. The results suggest that histamine synthesis may be required for the process of compaction and thus the formation of blastocyst.
The mechanism of cumulus cell‐oocyte uncoupling: Evidence for the participation of both cumulus cells and oocytes
Authors: Eppig John J. , Ward‐Bailey Patricia F. 
Published: February 2005

AbstractCumulus cells are metabolically coupled to oocytes via heterologous gap junctions. This coupling terminates near the time of ovulation, and the termination appears to be correlated with the mucification of the cumulus cells lying immediately adjacent to the oocytes. The first objective of this project was to determine whether follicle stimulating hormone (FSH) induction of cumulus cell‐oocyte uncoupling could occur independently of FSH‐stimulated cumulus mucification (expansion). Intercellular coupling was measured as a percentage of radiolabeled choline (or its metabolites) that was incorporated into the oocyte relative to the total amount of radiolabel incorporated into the entire cumulus cell‐oocyte complex. It was found that the complete suppression of FSH‐stimulated cumulus expansion with chondroitin sulfate B had no suppressive effect on FSH‐stimulated cumulus cell‐oocyte uncoupling. This finding showed that FSH‐stimulated cumulus expansion was not required for cumulus cell‐oocyte uncoupling. Since 17β‐estradiol, testosterone, or progesterone could not induce maximal cumulus cell uncoupling, it was concluded that the uncoupling‐promoting action of FSH was probably not mediated by steroid hormones.A partial uncoupling of cumulus cells and oocytes was found when spontaneous oocyte maturation had occurred in the absence of FSH. This partial uncoupling was prevented by incubation of cumulus cell‐oocyte complexes in concentrations of dibutyryl cyclic adenosine monophosphate (dbcAMP) or 3‐isobutyl‐1‐methyl xanthine (IBMX) (0.25 and 0.10 mM respectively) that suppressed spontaneous oocyte maturation without inducing cumulus expansion. These inhibitors also prevented the maximal induction of uncoupling that would have been provoked by biological grade preparations of either FSH or luteinizing hormone (LH). It was concluded that two factors were required to bring about maximal cumulus cell‐oocyte uncoupling: one factor was dependent upon the action of gonadotropins on cumulus cell function, the other factor appeared to be a function of the oocytes, since maximal uncoupling could occur only after the germinal vesicles had broken down.
Structural characterization of isolated rat epididymal epithelial cells
Authors: Olson G. E. , Jonas‐Davies J. , Hoffman L. H. , Orgebin‐Crist M.‐C. 
Published: February 2005

AbstractAn enriched suspension of rat epididymal epithelial cells was prepared by sequential enzymatic removal of connective tissue and peritubular cells from the epididymal tubule. The viability, structural characteristics, and pattern of polypeptides synthesized by the isolated cells were determined. Electron microscopic analysis revealed that the isolated principal cells were intact and retained their polarized morphology. Several light microscopic protocols were employed to evaluate the percentage of epithelial cells in the suspensions. These included (1) the visualization of the pattern of FITC‐lectin binding in which the principal cells could be identified by their polarized fluorescence; (2) the visualization of prominent autofluorescent granules in the cell cytoplasm which appeared to be characteristic of only epithelial cells; and (3) immunochemical staining with an antikeratin antibody which was reactive only with cells of epithelial origin. These structural probes indicated that between 80% and 90% of the isolated cells were epithelial in nature. Two‐dimensional gel electrophoresis revealed a complex pattern of polypeptides synthesized by the epithelial cells; these results are compared to those of earlier studies utilizing minced whole epididymis.
Analysis of preimplantation golden hamster conceptuses resulting from spermatozoa aged in utero
Authors: Bell Cindy L. , Shaver Evelyn L. 
Published: February 2005

AbstractThe effects of aging golden hamster spermatozoa in the female reproductive tract on the percentage of ova fertilized, the stage of development, and the chromosome complement of the resulting zygotes were studied. Females were inseminated artificially with cauda epididymal sperm at 6 h (control), 10, 15,18, or 21 h before the estimated time of ovulation. A decrease in the percentage of ova fertilized was found as the time spermatozoa were aged in utero prior to ovulation increased. The zygotes collected at 56 h postovulation from females inseminated 15 or 18 h prior to ovulation were delayed in development, as judged by the number of blastomeres. Although an increase of chromosomally abnormal zygotes was not found, a possibility exists that mosaicism may have been present, as evidenced by zygotes with unequal sized blastomeres, and went undetected.
Sea urchin cleavage is inhibited by ozone
Authors: Acevedo Mildred E. , Carroll Edward J. , Heath Robert L. 
Published: February 2005

AbstractThe first cell division of Strongylocentrotus purpuratus embryos which normally occurs at 84 min postinsemination (at 17°C) was specifically blocked by exposure to small amounts of ozone at 30 min postinsemination. Exposure of embryos to the same ozone level at 60 min postinsemination was teratogenic but did not block cell division. Previous work [Sweet et al, Science 209:931–933, 1980] using normal and several cancerous human cell lines showed that ozone blocked growth and proliferation; the present work shows that ozone specifically inhibits cleavage of sea urchin embryo cells that do not grow during the period of early development.
Detection and kinetics of the normal acrosome reaction of mouse sperm
Authors: Dudenhausen Elizabeth , Talbot Prudence 
Published: February 2005

AbstractA procedure is described for quantifying the percentage of normal acrosome reactions in fixed mouse sperm. This technique, which is a modification of the triple stain technique (TST) devised for human sperm [Talbot and Chacon, 1981a, b], utilizes trypan blue exclusion to identify the percentage of dead sperm in culture and subsequent staining of fixed sperm to differentiate the acrosome. Four classes of mouse sperm can be distinguished with the TST: (1) “live,” unreacted sperm, (2) “live,” acrosome‐reacted sperm (normal reactions), (3) dead, unreacted sperm, and (4) dead, acrosome‐reacted sperm (degenerative acrosome reactions). We have used this technique to study the time course of the normal acrosome reaction of mouse sperm in vitro. Our results with TST show that a low percentage of mouse sperm undergo normal acrosome reactions during the first 30 min of incubation; a maximum level of reactions is reached by 2 hr. Calcium was required in the medium for occurrence of normal reactions.
Analysis of lipid and protein components of ejaculated bull sperm surface and seminal plasma
Authors: Young Leona G. , Goodman S. A. 
Published: February 2005

AbstractSurface components of ejaculated bull sperm were radiolabeled by enzymatic iodination with lactoperoxidase and Na125I. The sperm were lysed and the labeled components analyzed on SDS‐7.5% polyacrylamide gels. Electrophoresis of solubilized radioactivity resolved six components with approximate molecular weights of 77, 61, 44, 36, 24, and 15 kilodaltons. To identify components that might be adsorbed to the bull sperm surface from seminal secretions, seminal plasma was labeled. Electrophoresis of labeled seminal plasma resolved four components with approximate molecular weights of 74, 33, 24, and 15 kilodaltons, each of which comigrated with a labeled sperm surface component. To identify the chemical composition of the radiolabeled components, labeled sperm surface and labeled seminal plasma were submitted to isopycnic density gradient centrifugation in cesium chloride. The 125I incorporated into bull sperm surface separated into two discrete areas of radioactivity, one having a density characteristic of protein and the other, of lipid. Iodinated seminal plasma banded in one discrete area that had a density characteristic of protein. Electrophoretic analysis of each area of radioactivity recovered from the gradients demonstrated that five of the six sperm surface and all of the seminal plasma components were in the protein fractions. The 15‐kilodalton sperm surface component banded as a lipid, whereas the 15‐kilodalton seminal plasma componènt banded as a protein.
Light microscopic observations of alterations in staining of the zona pellucida of porcine follicular oocytes: Possible early indication of atresia
Authors: Centola Grace M. 
Published: February 2005

AbstractSerial sections of porcine ovaries were examined in an attempt to detect early signs of oocyte degeneration/atresia using special staining. Porcine ovaries were fixed in Bouin's fixative and embedded in paraffin using routine techniques. Serial sections (8 μm) were mounted on glass slides and stained with Shorr's S3 and hematoxylin stain. Several criteria were used for examining general histology of the antral follicles: condition of the granulosa layer, antral cavity, the oocyte and its surrounding zona pellucida, and the cumulus layers. A change in the staining characteristic of the zona pellucida was the single most striking observation in all ovaries examined. In presumably healthy follicles, the zona pellucida was uniformly stained green, the granulosa layer was intact with fewer than three pyknotic cells per section, and a uniform basement membrane (stained green) separated the intact theca layers from the remainder of the follicle. In those follicles showing some degree of degenerative changes in the follicular wall, the zona pellucida was stained a bright orange. In the last stages of degeneration, follicles exhibited many pyknotic nuclei throughout the granulosa layers, the layer of granulosa cells was in many cases separated from the basement membrane, and the antrum was infiltrated with lymphocytes. In these follicles, the zona pellucida was always stained orange. Frequently, the zona pellucida was partially stained orange before any detectable changes could be seen in other elements of the follicular wall. Additionally, many non‐antral (primary) follicles exhibited oocytes with orange‐stained zonae pellucidae. In terminal stages of follicular degeneration, collapsed follicles were infiltrated by connective tissue elements stained bright orange and green. These structures very often contained dying oocytes always with bright orange‐stained zonae pellucidae. Scattered throughout the ovarian stroma were many orange‐stained remnants of zonae pellucidae. It is thought that perhaps the characteristic staining of the zona pellucida with Shorr's S3 stain may give an early, previously undetectable indication of follicular atresia.