bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reinvestigation of the ultrastructure of spermiogenesis and the spermatozoon of Hymenolepis nana (Cestoda, Cyclophyllidea), parasite of the small intestine of Rattus rattus
Authors: Bâ Cheikh Tidiane , Marchand Bernard 
Published: February 2005

AbstractSpermiogenesis in Hymenolepsis nana begins with the formation of a differentiation zone. This is limited at the front by arched membranes, is surrounded by cortical microtubules assoicated with 12 crested‐like bodies, and contains a single centriole made up of doublets. The distal centriole gives rise to a flagellum that grows at the same pace as the cortical microtubules. Migration of the nucleus takes place after the formation of the flagellum. It is followed by the separation of the old spermatid from the residual cytoplasm. The mature H. nana spermatozoon is filiform and lacks mitochondria. The axoneme, of the 9 + “1” pattern of the Platyhelminthes, does not reach the extremities of the spermatozoon. The nucleus is electron dense and is in close contact with the axoneme around which it coils in a spiral making an angle of 10° to 15° with the spermatozoon axis. The cortical microtubules follow a 10° to 15° helicoidal path along almost their whole length, except at their posterior extremity, where they are parallel to the spermatozoon axis. H. nana is distinguished by the early development of 12 crested‐like bodies of different lengths and by the existence of a single centriole in the differentiation zone. Such a high number of crested‐like bodies had never previously been reported in a cestode. © 1992 Wiley‐Liss, Inc.
The kinetics of oocyte activation and polar body formation in bovine embryo clones
Authors: Powell R. , Barnes F. L. 
Published: February 2005

AbstractThe kinetics of polar body formation were examined in parthenogenetically activated, in vitro matured and aged bovine oocytes. Subsequently, the presence or absence of polar body formation was determined in bovine embryo clones.Polar body formation, defined as telophase II, occurred by 1 (13/40, 43%) and 2 h (15/21, 71%) postparthenogenetic activation of metaphase II stage oocytes. Parthenogenetically activated oocytes readily formed pronuclei by 4 h. Some oocytes had chromatin in a highly condensed state at 1, 2, and 4 h postactivation (13/72, 18%). These oocytes often (10/13, 77%) appeared to be “self‐enucleated,” as the condensed chromatin was found in a membrane‐bound extrusion. The phenomenon was most prevalent when oocytes were handled at room temperature (25–27°C).Nuclear transfer procedures were established to bring about synchronous blastomere fusion and oocyte activation conditions. Synchronous conditions were achieved only when oocytes were handled and manipulated at 37–39°C. Embryo clones examined 2 h postfusion did not from a polar body. Conversely, nucleate demi‐oocyte controls were at the late telophase II stage of meiosis. The results are discussed in relation to cell cycle effects on bovine nuclear transfer. © 1992 Wiley‐Liss, Inc.
Cauda epididymal sperm interactions with seminal vesicle fluid
Authors: Curry Patrick T. , Atherton Robert W. 
Published: February 2005

AbstractThe interaction of rat cauda epididymal sperm cAMP‐dependent protein kinase (PKA) with seminal vesicle fluid (SVF) proteins was examined. Specific proteins in SVF act as substrates for the sperm cell PKA. The apparent molecular weights of these proteins are 45.0, 31.5, 17.2, 14.7, and 13.3 kDa. The phosphorylation of one low‐molecular‐weight cauda sperm protein is blocked in the presence of SVF. There is no PKA enzyme activity in SVF. The presence of phosphate transfer activity between the sperm cell enzyme and the SVF proteins is species dependent. For example, mouse and rat SVF proteins are efficient phosphate acceptors, but there is no phosphorylation activity when hamster SVF is used as the enzyme substrate. The sperm cell samples were also assessed for membrane integrity. Specifically, cauda sperm cells used in these assays were judged to be intact when examined microscopically using the fluorescent vital dye carboxyfluorodiacetate. Although there was enzyme activity in the supermatants of the rat sperm cell samples, in the protein kinase assay it required three times as much supernatant volume (compared with intact cell sample volume) to measure the activity. Supernatant enzyme activity did not increase with washing, indicating that the cells were not damaged by this procedure. The enzyme itself does not adhere to the sperm cells, so the PKA enzyme activity is most likely oriented on the external surface of the sperm cell. © 1992 Wiley‐Liss, Inc.
Secretion of bovine α‐lactalbumin into the milk of transgenic rats
Authors: Hochi Shin‐Ichi , Ninomiya Takashi , Waga‐Homma Miho , Sagara Junko , Yuki Atsushi 
Published: February 2005

AbstractBovine α‐lactalbumin (bβLA) gene prepared by polymerase chain reaction was introduced into rat genomes by microinjection. Out of 17 transgenic rat lines, 11 secreted bαLA into their milk at concentrations higher than 0.2 μg/ml. Of these, three lines secreted bαLA at concentrations higher than those in bovine milk. The highest concentration of bαĹ secreted into rat milk was 2,400 μg/ml. © 1992 Wiley‐Liss, Inc.
Porcine oocyte zona pellucida Mr 55,000 glycoproteins: Identification of O‐glycosylated domains
Authors: Yurewicz Edward C. , Pack Beverley A. , Sacco Anthony G. 
Published: February 2005

AbstractThe distribution of O‐linked oligosaccharides on the Mr 55,000 glycoproteins, ZP3α and ZP3, of the porcine oocyte zona pellucida was examined. Purified preparations of endo‐β‐galactosidase digested ZP3α and ZP3β were reduced and carboxamidomethylated and digested with trypsin. When the trypsin digests were mapped by HPLC, each glycoprotein yielded only one N‐acetylgalactosamine containing glycopeptide. Purification of the O‐glycopeptides was achieved by a two‐step protocol. Tryptic digests were applied to jacalin‐agarose and specifically‐bound O‐glycopeptides (αOGP and βOGP) were eluted with buffer containing 50 mM α‐methylgalactoside as the haptenic sugar. Further purification of each O‐glycopeptide was accomplished by reverse phase HPLC. Purified O‐glycopeptides were characterized with respect to amino acid and carbohydrate compositions and sequenced by automated Edman degradation; αOGP was a 41‐residue glycopeptide with three O‐linked sugar chains. Sequence comparisons revealed a 75% identity between αOGP and a corresponding segment of rabbit rec55 zona protein; OGP was a 25‐residue glycopeptide characterized by the presence of one N‐linked and five O‐linked sugar chains and a trypsin‐resistant internal arginine residue. Sequence alignments revealed an 80% or greater identity between βOGP and internal peptides of mouse, hamster and human ZP3 zona proteins. These studies demonstrate that in the case of ZP3α and ZP3β, the pig homologues of rabbit rec55 and mouse ZP3, respectively, O‐linked oligosaccharides are confined within delimited domains rather than widely dispersed on the polypeptide backbone. Such clustering of O‐linked oligosaccharides may represent an essential determinant of the structure and biological activity of zona proteins. © 1992 Wiley‐Liss, Inc.
Detection of chromosome 17‐ and X‐bearing human spermatozoa using fluorescence in situ hybridization
Authors: Han Tie Lan , Webb Graham C. , Flaherty Sean P. , Correll Anthony , Matthews Colin D. , Ford Judith H. 
Published: February 2005

AbstractFluorescence in situ hybridization (FISH) with DNA probes specific to chromosomes 17 and the X has been applied to human ejaculated sperm. After sperm nuclei were decondensed with EDTA and DTT, biotinylated alpha satellite DNA probes TR17 and TRX were separately used on preparations from thirteen healthy donors. After hybridization 96% of sperm were labelled with the TR17 probe and 48% of sperm were labelled with the TRX probe. Frequencies of 0.33% disomic 17 and 0.29% disomic X sperm were found. The frequencies of diploid sperm were assessed as 0.37% using the TR17 probe and 0.20% using the TRX probe which labelled only one half of the sperm; after correcting the result from the X‐probe to 0.40% the two frequencies are very similar. © 1992 Wiley‐Liss, Inc.
Behavior of sperm nuclei incorporated into parthenogenetic mouse eggs prior to the first cleavage division
Authors: Maleszewski Marek 
Published: February 2005

AbstractWhen artificially activated mouse eggs are inseminated in the middle of the first cell cycle, sperm nuclei remain condensed until the first mitosis. During mitosis of the first cleavage division sperm nuclei decondense, subsequently recondense and are passively displaced to the daughter blastomeres. In the 2‐cell embryos sperm nuclei form interphase nuclei which are able to replicate DNA and to condense into discrete chromosomes during the following mitotic division. These observations suggest that the mitotic cytoplasm of 1‐cell embryos creates similar conditions for the transformation of sperm nuclei into male pronuclei as the cytoplasm of metaphase ll oocytes. © 1992 Wiley‐Liss, Inc.
Protein dynamics in sperm membranes: Implications for sperm function during gamete interaction
Authors: Wolf D. E. , McKinnon C. A. , Leyton L. , Loveland K. Lakoski , Saling P. M. 
Published: February 2005

AbstractA number of mammalian sperm plasma membrane antigens have been implicated as playing a functional role in sperm‐egg interaction, by virtue of the fact that antibodies against these antigens interfere with fertilization. Two such muse sperm plasma membrane antigens are M42, a 200/220 kD glycoprotein doublet, and M5, a 150–160 kD glycoprotein. We show that both of these antigens are concentrated on the posterior region of caudal epididymal and capacitated mouse sperm heads and are relatively diffusible, as determined by fluorescence recovery after photobleaching measurements (D = 3–8 × 10–9 cm2/s with ∼ 23% diffusing). Crosslinking of these antigens with bivalent antibodies causes them to redistribute into the anterior region (acrosomal crescent) of the sperm head. In contrast, we describe a third antigen, P220, which is also localized to the posterior region of the sperm head on caudal epididymal sperm but which exhibits very little diffusion and does not redistribute upon crosslinking. Bivalent anti‐M42 blocks the ZP3‐induced acrosome reaction. We have found that monovalent Fab fragments of anti‐M42 do not block the ZP3‐induced acrosome reaction, but that inhibition is restored by addition of a second antibody which crosslinks the Fabs. Thus, crosslinking is required for both inhibition of the acrosome reaction and redistribution. This suggests that redistribution of antigen away from the posterior region of the head may be part of the mechanism of inhibition of the ZP3‐induced acrosome reaction. © 1992 Wiley‐Liss, Inc.
Genome exclusion and gametic dapi—dna content in the hybridogenetic Bacillus rossius—grandii benazzii complex (insecta phasmatodea)
Authors: Tinti Fausto , Scali Valerio 
Published: February 2005

AbstractAmong Sicilian stick insects, two hybridogenetic complexes have been discovered: Bacillus rossius–grandii benazzii and B. rossius–grandii grandii, which also produce androgenetic offspring. The egg maturation of the former is analyzed here through DAPI fluorom etry, which, besides the assessment of the meiotic stages, also allows their DNA measurements and the analysis of sperm‐head evolution into male pronuclei in these polyspermic eggs.Hybridogenetic eggs undergo an extrasynthesis of chromosomes, because two groups of n autobivalents (4C each) are segregated at metaphase 1st; the two groups must correspond to the pure parental species haplosets. Then the grandii chromosomes degenerate (1st polar body), while the rossius chromosomes divide further to produce two groups of n autodiads (2C each); one of them degenerates (2nd polar body), and the other is ready to perform syngamy (female pronucleus). Meanwhile, several B. grandii sperm evolve into male pronuclei by doubling their DNA (from 1C to 2C content) and assuming an interphase nucleus appearance. If regular mixis occurs, the F1 hybrid constitution is restored but, if it fails, a fusion between two sperms may occur, originating fully paternal descendants (natural androgenesis). The genome exclusion mechanism of stick‐insect hybridogens appears to be more primitive than those observed in the already known hybridogenetic complexes of Poeciliopsis and Rana esculenta.Unfertilized eggs of hybridogens are capable of self activation, but the cytology of the related clonally reproducing B. whitei indicates that its parthenogenetic mechanism stems from the hybridization event (hybrid theory) rather than from tychoparthenogenetic potentialities (spontaneous theory). © 1992 Wiley‐Liss, Inc.
Okadaic acid and p13suc1 modulate the reinitiation of meiosis in mouse oocytes
Authors: Gavin Anne‐Claude , Vassalli Jean‐Dominique , Cavadore Jean‐Claude , Schorderet‐Slatkine Sabine 
Published: February 2005

AbstractShort‐term exposure to okadaic acid (OA), a specific inhibitor of protein phosphatases 1 and 2A, induced resumpton of meiosis, including metaphase spindle formation, in mouse oocytes treated with a phosphodiesterase inhibitor, while long incubations with OA arrested oocyte maturation at a step prior to spindle formation. To explore the basis for this difference, the overall patterns of protein synthesis and phosphorylation and the production of tissue‐type plasminogen activator (tPA), the synthesis of which is induced after germinal vesicle breakdown (GVBD), were analyzed under various OA treatments. Short‐term exposure to OA led to tPA production and did not greatly affect the maturation‐associated changes in protein phosphorylation. By contrast, a long application of OA did not result in tPA production and induced more marked changes in protein phosphorylation.Microinjection into prophase oocytes of the the product of the fission yeast gene p13suc1, known to inhibit p34cdc2 kinase activation and/or activity, prevented meiotic reinitiation. This effect was overcome by microinjection of OA, at concentrations higher than those required for induction of maturation in the absence of p13suc1. These observations suggest that inhibition of phosphatase 1 or 2A or both triggers meiotic resumption by acting at the same site or at a site proximal to the p13suc1‐sensitive step of cdc2 kinase activation. © 1992 Wiley‐Liss, Inc.
Analysis of the DNA binding proteins interacting with specific upstream sequences of the S. purpuratus CyI actin gene
Authors: Ganster Raymond , Paul Hyacinth , Katula Karen S. 
Published: February 2005

AbstractThe Cyl actin gene of the sea urchin, Strongylocentrotus purpuratus, is regulated temporally and spatially within the cells of the early embryo. In an effort to understand the molecular basis for the Cyl actin pattern of expression, we have begun analyzing the protein–DNA interactions within regions previously shown to be of potential functional importance (Katula et al., 1987). Using DNase I footprinting, 10 protected regions were identified containing both conserved and apparently novel protein binding sites. Gel mobility shift competition assays confirmed the presence of multiple protein factors which specifically recognize Cyl actin upstream sequences. Determination of a relative affinity constant value (Kr) indicated that most of the protein factors preferred their respective oligonucleotide sequences vs. a synthetic competitor DNA in a range of 104. The highest affinity binding was observed for proteins binding to the oligonucleotide probe containing theoctamer element (Kr ≈︁ 106). Heterologous gel shift competition assays were carried out to investigate the interrelatedness of the protein factors. These studies, combined with other data, indicate there are both unique and redundant protein–DNA interactions in the region being examined. Possible alterations in Cyl actin DNA binding proteins were investigated during the period of Cyl transcriptional activation by gel mobility shift analysis. An increase in binding activity was observed for most of the factors, indicating that early transcriptional activity of Cyl actin may involve a general increase in the amount or activity of specific transcription factors. In addition, qualitative changes, as seen by alterations in the shift patterns, were observed for some of the oligonucleotide probes. © 1992 Wiley‐Liss, Inc.
Characterization of fibronectin as a marker for human epididymal sperm maturation
Authors: Miranda Patricia V. , Tezon Jorge G. 
Published: February 2005

AbstractFertilization involves adhesive interactions between gametes similar to those mediated by fibronectin (FN) in other cellular systems. Fibronectin has been found on the equatorial segment of ejaculated human sperm. As sperm capacity to interact with the oocyte is acquired during epididymal transit, the possible participation of FN in human sperm maturation was studied. The presence of FN in both epididymal sperm and fluid was demonstrated by the detection of a major component of 220 kD in immunoblot studies using anti‐FN antisera. The concentration of FN in soluble tissue extracts of epididymis was determined by enzyme‐linked immunosorbent assay (ELISA). A gradual increase along the length of the organ, averaging 12‐fold from proximal caput to distal corpus, was detected. Immunocytochemistry assays indicated that the number of spermatozoa with immmunoreactive FN over the equatorial segment increased from 18% in caput to 64% in distal corpus epididymis. Immunoprecipitation of medium from epididymal explants culture with anti‐FN antiserum demonstrated the de novo synthesis of FN in vitro. The greater number of FN‐positive sperm coincident with FN accumulation in distal regions of the epididymis supports the role of FN in sperm maturation. © 1992 Wiley‐Liss, Inc.
A comparison between in vitro fertilization and microinjection of immobilized spermatozoa from bulls producing spermatozoa with defects
Authors: Heuwieser W. , Yang X. , Jiang S. , Foote R. H. 
Published: February 2005

AbstractThe objectives of this study were to compare the fertilization rate of bovine in vitro matured oocytes by in vitro fertilization (IVF) and by microinjection of a single spermatozoon (MI) and to relate these rates with fertility reported for these bulls in artificial breeding. Bull A (Holstein) had a nonreturn rate of 75%. Semen from this bull is routinely used in our standard IVF procedure. Bull B (Ayrshire), used regularly in artificial breeding and related to bull D, had a nonreturn rate of 69.2%. Bull C (Brown Swiss), with a chromosomal translocation and trisomy, achieved a nonreturn rate of 42%. Bull D (Ayrshire) produced nonmotile spermatozoa (SPZ) and had an abnormality described as “tail stump defect.” No pregnancies sired by bull D have been reported. Oocytes were either fertilized in vitro by capacitated SPZ or by microinjection of a single immobilized SPZ into the ooplasma. SPZ were treated with 0.1 μM A23187 and used for IVF. For microinjection SPZ were cocultured for 5 h with bovine oviduct epithelial cells (BOEC) and then immobilized by freezing and thawing twice without cryoprotectant. A single batch of killed SPZ (stored at – 25°C) was used for all microinjections. All oocytes were cultured in Medium 199 for 22 h at 39°C and subsequently fixed, stained, and examined for evidence of fertilization (i.e., female and male pronucleus formation, SPZ decondensation). Fertilization rates following IVF with semen from bulls A, B, C, and D were 80%, 54%, 1%, and 2%, and following microinjection were 39%, 22%, 21%, and 34%, respectively. © 1992 Wiley‐Liss, Inc.
Embryo sex selection by a rat male‐specific antibody and the cytogenetic and developmental confirmation in cattle embryos
Authors: Utsumi Kyozo , Hayashi Mikio , Takakura Ryo , Utaka Kenji , Iritani Akira 
Published: February 2005

AbstractEmbryos of mouse, rabbit, goat, sheep, and cattle were separated into 2 groups on the basis of their morphology when incubated with a male‐specific antibody (qualified here as the H‐Y antibody) prepared from newborn rat testis. When morula‐stage embryos were cultured in the presence of this H‐Y antibody, the development of roughly one half of the embryos was arrested at that stage, whereas the other half continued to develop to the blastocyst stage. The developmentaly arrested group of embryos resumed their development into blastocysts when cultured in antibody‐free medium. Eighty to 90% of cattle embryos whose development was unaffected by the antibody were shown to possess a female karyotype (XX), and close to 80% of those embryos whose development was arrested possessed a male karyotype (XY). Cattle embryos whose sex had been presumptively identified by development in the presence of the H‐Y antibody were cryopreserved and transferred, and the sex of the calves was examined. The overt sex of the young born from sexed embryos was found to be the same as that determined by chromosomal analysis. © 1993 Wiley‐Liss, Inc.
Differential chromatin condensation of female and male pronuclei in mouse zygotes
Authors: Ciemerych Maria A. , Czołowska Renata 
Published: February 2005

AbstractMouse zygotes or halves of zygotes, containing either a female or a male pronucleus, were fused with ovulated metaphase II oocytes. In 59.7% of the resulting hybrid cells, the pronuclei underwent premature chromosome condensation (PCC). In some of these heterokaryons the 2 pronuclei differed in the dynamics of condensation. Detectability of differential PCC of pronuclei (dPCC) depended on the type of preparation. In hybrids with PCC, produced by fusion of intact zygotes with metaphase II oocytes and processed for whole‐mount preparations, one pronucleus was more advanced in the condensation process in 47% of cases. In air‐dried preparations dPCC was detected in as many as 94% of hybrids. Experiments with the fusion of halves of zygotes with metaphase II oocytes have shown that the differential reaction of pronuclei to condensation factor depended on their parental origin. Maternal chromatin responded faster to the condensation factor and attained more advanced stages of PCC than paternal chromatin. Different responses of the maternal and paternal pronucleus to the condensation factor suggests that the 2 pronuclei are not identical with regard to the organization of chromatin and/or the lamin composition of the nuclear envelope. © 1993 Wiley‐Liss, Inc.
Characterization of a cDNA clone coding for human testis membrane cofactor protein (MCP, CD46)
Authors: Cervoni Florence , Fenichel Patrick , Akhoundi Camelia , Hsi Bae‐Li , Rossi Bernard 
Published: February 2005

AbstractMembrane cofactor protein (MCP) is a complement regulatory protein that acts as a cofactor for the cleavage of C3b and C4b by the serine protease factor I. We have previously reported the characterization of a functional MCP molecule on the acrosomal membrane. This protein migrated as a single band with a molecular weight of 40,000 Da, which is 10,000–20,000 Da smaller than the known MCP molecules, and is devoid of N‐and O‐linked sugars. We have proposed that the difference in molecular weight resulted from the lack of sugars. To investigate if this is due to the absence of glycosylation sites, we have characterized a cDNA clone from a human testis cDNA library. This cDNA corresponds to a peculiar MCP form previously described, which is characterized by the presence of the serine/threonine/proline‐rich exon C (STPC) and the cytoplasmic tail known as CYT2, and we conclude that the absence of mature oligosaccharide of the sperm MCP cannot be totally attributed to a defect of N‐ and O‐glycosylation sequences but rather reflects an alteration of the mechanisms of glycosylation in spermatozoa. The presence of functional MCP on the acrosomal membrane, as well as the other complement regulatory protein, decay‐accelerating factor, strongly suggests that these proteins may act concomitantly to protect the acrosome‐reacted spermatozoa from the attack of the complement present in the female genital tract. © 1993 Wiley‐Liss, Inc.