bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diadem/crater defects in spermatozoa from two related angus bulls
Authors: Larsen Rolf E. , Chenoweth Peter J. 
Published: February 2005

AbstractThe diadem/crater defect was studied over several months in two related 20‐month‐old Angus bulls. In bull 1, diadem/crater defects were present in 2–99% of ejaculated spermatozoa at various times during the evaluation period. In bull 2, affected cells varied from 20% to 94%, with other abnormalities (head and acrosome defects, coiled tails, proximal cytoplasmic droplets) also common. Single sire mating trials conducted over 26 days during an apparent recovery phase showed normal fertility (approximately 50% pregnancies per estrus exposed). Both resting and gonadotropin‐releasing hormone (GnRH)‐stimulated testosterone values were within nor‐mal limits. Histopathological evaluation of testes showed no obvious hypoplastic, inflammatory, or degenerative condition. Electron microscopy of ejaculated spermatozoa demonstrated the characteristic diadem pattern of craters in the equatorial region of the head. Many cells from bull 2 contained large craters in other regions of the nucleus. Electron microscopy of testicular tissue demonstrated nuclear invaginations lined by a single unit membrane in round spermatids. Lesions in elongated spermatids were more pronounced, with curling of the nucleus and large membrane‐filled cavities in the chromatin occurring in addition to craters in the equatorial region of the nucleus.
Sequences of the CyIIIa actin gene regulatory domain bound specifically by sea urchin embryo nuclear proteins
Authors: Thézé Nadine , Calzone Frank J. , Thiebaud Pierre , Hill Ronald L. , Britten Roy J. , Davidson Eric H. 
Published: February 2005

AbstractExpression of the Cylla cytoskeletal actin gene is a marker of differential gene activation in the aboral ectoderm of the early sea urchin embryo. Gene transfer expreiments have defined a 2,300 nucleotide cis‐regulatory domain required for the correct spatial and temporal control of this gene. This domain includes at least 20 sites at which relatively stable DNA‐protein complexes form in vitro on reaction with embryo nuclear extracts. We report the nucleotide sequence of the whole regulatory domain and map the sites at which high‐specificity DNA‐protein interactions occur. These were located initially by gel shift assays carried out on progressive restriction digests of given subfragments of the large regulatory domain and were located more exactly by oligonucleotide gel shift competitions. Eight of the sites of specific interaction are unique within the Cyllla regulatory domain, and the remainder consist of five different sites that occur more than once. We observe some well known sequences also found in regulatory regions of other genes, e.g., “CCAAT” and “octamer” elements. The various sites have been classified regarding putative biological function in other work, and the present studies permit an assessment of the number and complexity of interactions constituting each functional class and of the relative locations of sites of each class.
Induction and inhibition of meiotic maturation of amphibian (Rana dybowskii) follicular oocytes by forskolin and cAMP in vitro
Authors: Kwon Hyuk B. , Park Hyun J. , Schuetz Allen W. 
Published: February 2005

AbstractPrevious studies have demonstrated that direct or indirect elevation of cAMP levles in cultured amphibian ovarian follicles simultaneously stimulated production of oocyte maturation‐inducing steroid (progesterone) by the follicles and inhibited oocyte maturation induced by endogenous or exogenous hormone. The duration of cAMP stimulation influenced arrest and reinitiation of oocyte meiotic maturation in ovarian follicles of Rana dybowskii. Addition of forskolin (adenylate cyclase stimulator) to cultured follicles inhibited both progesterone‐ and frog pituitary homogenate (FPH)‐induced oocyte maturation. Similar inhibitory results were obtained when hormone‐treated follicles were cultured in the continual presence of cAMP. Oocyte maturation increasingly occurred in follicular oocytes when cAMP or forskolin addition was delayed following treatment with FPH or progesterone. Transient exposure (6–8 hr) of ovarian follicles to forskolin or cAMP markedly stimulated oocyte maturation as well as accumulation of progesterone as measured by radioimmunoassay within the ovarian follicles. Forskolin was more effective than cAMP, at the dose tested, in stimulating progesterone production and accumulation by the follicles. The data demonstrate that transient manipulation (elevation) of cAMP levels in cultured follicles, without added FPH or steroid, was sufficient to initiate oocyte maturation. Results suggest that, with transient exposure to forskolin or exogenous cAMP, there is a sequential increase and decrease in endogenous cAMP levels in the somatic cells and germ cell components of the ovarian follicle. These changes appear to mediate production of maturation‐inducing steroid and secondarily allow its effects on the oocyte to be expressed.
Protamine amount and cross linking in mouse teratospermatozoa and aneuploid spermatozoa
Authors: De Boer P. , Redi C. A. , Garagna S. , Winking H. 
Published: February 2005

AbstractThe level of SH‐group oxidation in spermatozoa from the cauda epididymis was measured by a cytofluorometric method in chromosomally normal mice and two chromosome mutants. The first one, a tertiary trisomic karyotype (Ts(113)7OH), is characterized by severe oligospermia and high levels (≈75%) of malformed spermatozoa. The second, a hybrid between two European feral mouse stocks, is heterozygous for multiple Robertsonian translocations and produces exclusively aneuploid spermatozoa. Neither the severe teratospemiogenesis nor the severe aneuploidy was reflected in total SH‐group fluorescence values nor in free SH‐group fluorescence. It is concluded that both the production of protamines and protamine cross linking by S‐S bridge formation are rather autonomous processes during spermatogenesis because (1) the increased DNA variance of the aneuploid spermatozoa is not reflected in an increased variance of the total and free SH‐groups, (2) aneuploidy for the protamine gene carrying chromosome 16 is not reflected by the SH‐group values for individual spermatozoa, and (3) protamine production and cross linking are independent of the mild to severe terataspermiogenesis in the tertiary trisomic karyotype.
Temporal and spatial transcriptional regulation of the aboral ectoderm‐specific spec genes during sea urchin embryogenesis
Authors: Tomlinson Craig R. , Klein William H. 
Published: February 2005

AbstractmRNAs for Spec 1 and Spec 2 of Strongylocentrotus purpuratus and LpS1 of Lytechinius pictus accumulate only in the aboral ectoderm of developing embryos. In vitro nuclear transcription assays were done to study the transcriptional regulation of these cell type‐specific genes. Spec 1, Spec 2c, and Spec 2d genes all appeared to be transcriptionally activated at the late cleavage‐early blastula stage of S. purpuratus. Differences in the relative transcription rates during development appeared to play a major role in determining the relative levels of the various Spec mRNAs. The L. pictus LpS1 gene was transcriptionally activated at a similar developmental time as the corresponding S. purpuratus genes. Nuclei from gastrula or pluteus ectodermal and endodermal/mesodermal cell fractions were used to demonstrate that Spec 1 and LpS1 genes were transcriptionally active in ectoderm nuclei but not in endoderm/mesoderm nuclei, suggesting that in vivo the Spec 1 and LpS1 genes are spatially controllod at the transcriptional level. Estimations of the absolute rate constants for Spec 1 transcription were mado at the late cleavage, mesenchyme blastula, and midgastrula stages. Calculations using these rate constants and the known levels of Spec 1 mRNA suggested that Spec 1 mRNA stability gradually increased throughout development.
Identification of extracellular proteins in the rat cumulus oophorus
Authors: Virji Nassim , Phillips David M. , Dunbar Bonnie S. 
Published: February 2005

AbstractWe have examined the proteins associated with the mucous matrix of the rat cumulus oophorus and compared them to the composition of rat serum, follicular fluid, ampullary fluid, and oocyte–cumulus cell extract. The cumulus matrix was dispersed using Streptomyces hyaluronidase, and the proteins were analyzed by highresolution two‐dimensional polyacrylamide gel electrophoresis and compared with proteins of the serum, proestrous follicular fluid, and postvulatory ampullary fluid and extracts of oocytes and cumulus cells. In addition to albumin and transferrin, which were common to all the fluids analyzed, the cumulus material contained many proteins in common with the follicular fluid and the ampullary fluid. However, the protein extract of the cumulus matrix also contained four major proteins not present in the other fluids analyzed. Two of these proteins were acidic and heterogenous in charge and size (MW ∼81,000 and 100,000). The other two proteins were more basic and occurred at MW ∼90,000 and 150,000. Our results show that the extracellular matrix of the cumulus contains proteins that are not present in the fluids that surround the oocyte.
Penetration of intact bovine ova with ram sperm in vitro
Authors: Slavík T. , Pavlok A. , Fulka J. 
Published: February 2005

AbstractIn culture, mature bovine ovarian oocytes were fertilized in vitro with freshly ejaculated ram spermatozoa treated with heparin. The zona pellucida does not prevent penetration of ram spermatozoa. The penetration rate varied between 10 and 84%, and in most instances, after 24 hr of culture, two normal‐looking pronuclei and sperm tail were present in the cytoplasm. These results suggest that the zona pellucida of bovine oocytes does not represent a barrier for the penetration of ram spermatozoa.
Histochemical identification of primordial germ cells in diandric and digynic triploid mouse embryos
Authors: Kaufman M. H. , Lee K. K. H. , Speirs S. 
Published: February 2005

AbstractDiandric and digynic triploid mouse embryos were isolated in the morning on day 10 of gestation. The embryos were separated from their extraembryonic membranes, and the latter were analysed cytogenetically by G‐banding to establish the ploidy and sex chromosome constitution of these embryos. The diandric triploid embryos were produced by the technique of nuclear micromanipulation. Females were mated with male mice with a morphologically distinguishable “marker” chromosome to confirm the diandric status of these embryos. Digynic triploid and normal diploid embryos were isolated form LT/Sv strain females. These females spontaneously ovulate both primary and secondary oocytes, which are fertilisable and give rise to digynic triploid and normal diploid embryos, respectively. All the embryos were serially sectioned and processed in order to dmonstrate the presence of alkaline phosphatase enzyme activity. This histochemical technique allowed primordial germ cells to be readily recognised, due to their characteristic location, cellula morphology, and staining appearance. Primordial germ cells were found in all the embryos studied, being located within the visceral yolk sac, at the base of the allantois, and/or in association with the wall or mesentery of the hindgut. The total number of germ cells present was established in nine diandric triploids and in five digynic triploids. The findings presented here represent the first demonstration that primordial germ cells can differentiate in either diandric or digynic triploid mammalian embryos.
Production and characterization of monoclonal antibodies to the mammalian sperm cytoskeleton
Authors: Macrae Thomas H. , Lange Bodo M. H. , Gull Keith 
Published: February 2005

AbstractThe cytoskeleton exerts a direct effect on the function of sperm by influencing the distribution of subcellular organelles and plasma membrane molecules. We have prepared six monoclonal antibodies to Triton X‐100‐insoluble components of the bull sperm cytoskeleton. One of the antibodies reacts with a detachable portion of the bull sperm acrosome. The remainder include an antibody that recognizes the principal and end piece of the tail and another that is specific to the middle piece. Two of the antibodies yield dissimilar staining patterns of the neck region and the tail, and the final monoclonal antibody stains the subacrosomal region and a detachable acrosomal domain of bull sperm. The cross reactivities of the antibodies with hamster sperm and PtK2 cells are described, as is the recognition of bull sperm polypeptides on western blots. The results suggest that these antibodies will provide interesting insights concerning the role of the cytoskeleton in sperm development and function.
Effects of gossypol on the motility of mammalian sperm
Authors: Porat Offie 
Published: February 2005

AbstractThe effects of the male contraceptive gossypol on the motility of mammalian spermatozoa are reviewed. The role of sperm motility in the processes of fertilization and the effect of the drug on these processes determine its effectiveness as a contraceptive. The promising male contraceptive potential of gossypol is discussed in the context of the serious adverse effects of the agent.
Expression of a sperm protein gene during spermatogenesis in mammalian testis: An in situ hybridization study
Authors: Wang Linfang , Miao Shiying , Yan Yuanchang , Li Yuehua , Zong Cong , Koide S. S. 
Published: February 2005

AbstractIn previous work a specific membrane protein with an estimated Mr of 20.1 kDa was purified from rabbit sperm tails and designated as rSMP‐B protein. Antibodies were raised against rSMP‐B protein and used to isolate and identify the cDNA coding the rSMP‐B protein from a rat testis λgt11 expression library. The nucleotide sequence of the cDNA was determined in a previous study. Single‐stranded 35S‐labeled RNA probes were prepared. With the techniques of in situ hybridization, rSMP‐B mRNA was detected in spermatids of rat and rabbit testis. The present results support our previous observation that immunization of male rabbits with the rSMP‐B protein results in the arrest of spermatogenesis at the spermatid stage. Overall, rSMP‐B protein appears to be involved in spermiogenesis, and the synthesis of the mRNA encoding the protein occurs in germ cells during the postmeiotic haploid phase of spermatogenesis.
Survival of bisected rabbit morulae transferred to synchronous and asynchronous recipients
Authors: Yang Xiangzhong , Foote R. H. 
Published: February 2005

AbstractThe rabbit was used as a model to test the concept that temporal asynchrony is required to establish physiological synchrony when embryos are bisected to produce demiembryos. In preliminary studies with intact embryos it was confirmed that embryos harvested on days 2,3,4, or 5 (day 0 = day of breeding) can be transferred with ± 1 day of asynchrony to the uteri of recipient rabbits. Three experiments were conducted with bisected embryos. In experiment 1, 192 bisected and 194 control day 3 embryos were transferred to uteri of day 2,2.5, and 3 recipients (ovulated 0, 12, and 24 h after the donors), with 14% of the bisected and 39% of the intact embryos (P < .05) resulting in young. Only 4% (2/48) of the day 3 bisected embryos vs. 39% (P < .05) of the intact day 3 embryos survived in the uteri of day 2 recipients. In experiment 2, day 3 bisected and intact embryos were transferred to the oviducts of day 3, 3.5, or 4 recipients, the speculation being that the oviduct might provide a more neutral enviroment than the uterus. However, embryo survival was very low, except for the intact embryos transferred to synchronized recipients (42% young born). In experiment 3, 150 intact and 162 (81 pairs) bisected day 3 embryos collected from uteri were transferred to uteri of day 2.5, 3.0, and 3.5 recipient does. Significantly more pregnancies (100% vs. 47%, P < .01) and young born (56% vs. 19%, P < .01) resulted from intact embryos than from bisected embryos, irrespective of the uterine age. Asynchrony (±0.5 days) did not affect pregnancy rate or young born from day 3 intact embryos, but bisected embryos are more sensitive to uterine or oviductal environment than whole embryos; survival was higher (P < .05) when they were transferred to day 2.5 recipients.
Effect of follicle cells on the acrosome reaction, fertilization, and developmental competence of bovine oocytes matured in vitro
Authors: Fukui Y. 
Published: February 2005

AbstractThe role of follicle cells in the acrosome reaction of frozen‐thawed bovine spermatozoa, in vitro fertilization, cleavage, and development in vitro was investigated. Cumulus‐oocyte complexes were cocultured and matured in vitro with additional granulosa cells for 24 hr. Immediately before in vitro insemination, the oocytes were divided into three types with different follicle cells: denuded and corona‐ and cumulus‐enclosed oocytes. The proportion of live, acrosome‐reacted spermatozoa significantly increased at 3 and 6 hr after insemination in all types of oocytes. However, the mean proportion of live, acrosome‐reacted spermatozoa that inseminated cumulus‐enclosed oocytes at 6 hr after insemination was significantly higher than that of spermatozoa inseminating denuded oocytes (18.3% and 13.3% respectively). The frequency of in vitro fertilization was significantly higher for cumulus‐enclosed oocytes (65.4%) than for denuded and corona‐enclosed oocytes (30.8% and 39.4%, respectively). Cumulus‐enclosed oocytes when cocultured with oviduct epithelial cells also had significantly higher rates of cleavage (two‐ to eight‐cell, 59.8%; eight‐cell, 22.4%) and blastocyst formation (7.7%) than denuded and corona‐enclosed oocytes. No eight‐cell embryos or more advanced stages of embryonic development were observed in either denuded or corona‐enclosed oocytes without the coculture. The present results indicate that cumulus cells at fertilization play an important role in inducing the acrosome reaction and promoting a high fertilization rate, cleavage, and development into blastocysts in vitro.
Time‐Lapse analysis and normal stages of development of cleavage and blastocyst formation in the marsupials the brown antechinus and the stripe‐faced dunnart
Authors: Selwood Lynne , Smith David 
Published: February 2005

AbstractThe first six normal stages of celavage and blastocyst formation in vitro of the brown antechinus and the stripe‐faced dunnart are described based on 429 embryos from 37 dunnarts and 143 embryos from 32 antechinus and on information from previous studies. Embryos were cultured in Dulbecco's modified Eagle's medium with high glucose and 10% foetal calf serum at 35oC and 5% CO2 in air. Seven antechinus and 18 dunnart embryos were cultured in Rose chambers and filmed by time‐lapse cinematography, with an exposure of 0.2 sec and at a rate of 1 frame/30 sec. A rim of zona was formed around the yolk mass during early cleavage. Blastomeres attached to this rim, ensuring that the zona in the hemisphere containing the yolk mass was the first to be lined by blastomeres during blastocyst formation, which is completed at about the 32‐cell stage. Two foci were established during cleavage. The descendants of the first cell to divide at the four‐cell stage included, at both the fourth and fifth division, the first cell to divide and the cell with the shortest cell cycle time and had the shortest average cell cycle time at each division. The descendants of the cell opposite the first cell to divide at the four‐cell stage included, at both the fourth and fifth divisions, the last cell to divide and the cell with the longest cell cycle time and had the longest average cell cycle time at each division.
Ca2+ uptake during capacitation of mouse spermatozoa and the effect of an anion transport inhibitor on Ca2+ uptake
Authors: Ruknudin A. , Silver I. A. 
Published: February 2005

AbstractWith a specially constructed chamber, Ca2+ uptake by mouse spermatozoa was monitored continuously during capacitation and the acrosome reaction. It was shown, using calcium ion‐selective microelectrodes, that there was an initial uptake of Ca2+ by spermatozoa undergoing capacitation. Such net transport was also promoted by the divalent cation ionophores A23187 or ionomycin. An anion inhibitor, SITS, produced dose‐dependent inhibition of Ca2+ uptake. This inhibitor reduced the incidence of capacitation as revealed by a reduction in the B pattern by chlortetracycline (CTC) assay and thus inhibited fertilization, suggesting that anions are involved in calcium uptake in mouse spermatozoa.
Effect of equilibration period on the viability of frozen‐thawed mouse morulae after rapid freezing
Authors: Takahashi Yoshiyuki , Kanagawa Hiroshi 
Published: February 2005

AbstractMouse morulae were frozen with 1.5–4.0 M glycerol + 0.25 M lactose solution by direct plunging into liquid nitrogen vapor 0.5–30 min after equilibration at room temperature. After thawing, embryos were cultured in vitro, and the highest survival rates were obtained after exposure for 3 min at 3.0 and 4.0 M and for 5 min at 1.5 and 2.0 M glycerol levels. Significant reductions in the survival rates (P < 0.05) were observed when equilibration periods were extended for 3–5 min at 3.0 and 4.0 M and for 5–10 min at 1.5 and 2.0 M glycerol levels. These results clearly demonstrate that the equilibration time of embryos in glycerollactose mixture is one of the most important factors in the present rapid freezing conditions. To clarify the factors that lower embryo viability after prolonged equilibration, we performed further experiments on the effects of exposure to glycerol‐lactose mixture on the developmental potential of embryos without freezing and on the volume changes of embryos during the exposure to glycerol solution with or without lactose. It was suggested that the detrimental effects of prolonged equilibration are due not only to the toxicity and osmotic injury of higher concentrations of cryoprotectant solution but also to the influx of water into embryonic cells caused by the hypotonic salt concentration of the extracellular (freezing) solution.
Activation of cumulus‐free mouse oocytes
Authors: Marcus G. J. 
Published: February 2005

AbstractAttempts were made to activate parthenogenetically oocytes from randombred mice under conditions required for nuclear transfer, viz. in the absence of cumulus cells. Of the large number of stimulants previously described and presumed to be generally effective, only exposure to strontium ion (as a replacement for calcium ion in the medium), or to calcium ionophore, activated a substantial proportion of cumulus‐free oocytes from TRf mice, a synthetic, random‐bred strain. These stimuli were less effective in oocytes from random‐bred ICR mice. The relevance of the findings to nuclear‐transfer cloning attempts in mice is discussed.