bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of scatter factor/hepatocyte growth factor is regionally correlated with the initiation of sperm motility in murine male genital tract: Is scatter factor/hepatocyte growth factor involved in initiation of sperm motility?
Authors: Naz Rajesh K. , Joseph Ansamma , Lee Yuan , Ahmad Khaliq , Bhargava Madhu M. 
Published: February 2005

AbstractBased upon findings that the scatter factor/hepatocyte growth factor (SF/HGF) has strong mitogenic and motogenic properties, and that the sperm cell acquires its fertilizing capacity and motility in the distal parts of mammalian epididymis, the present study was conducted to investigate the role of SF/HGF in initiation of sperm cell motility. This was investigated by determining the expression of SF/HGF in various regions of the murine male genital tract by scatter and cell tracking assays using MDCK epithelial cells, Western blot procedure, and the immunohistochemical procedure using paraffin sections of various regions of the male genital tract. The findings from all these assays indicate that SF/HGF is differentially expressed in various parts of the male genital tract with slight or no expression in the testes, caput epididymis, and vas deferens, and with the highest expression in cauda and corpus (distal) epididymis followed by expression in the corpus (proximal) epididymis. This region‐specific SF/HGF expression pattern coincides with the pattern of acquiring the fertilizing capacity and motility by the sperm cell during its transit through the male genital tract. However, wherever SF/HGF was expressed in the male genital tract, its molecular weight was slightly higher (Mr, 82 kD), compared to the SF/HGF expressed in various other somatic tissues (Mr, 78 kD), indicating that the genital tract SF/HGF may be a different molecular species that shares some immunoreactive epitopes with the somatic cell SF/HGF. Incubation of immotile sperm from caput epididymis with the purified human placental SF/HGF of 78 kD initiated motility in 5–15% of sperm population. These results strongly suggest that the SF/HGF‐like activity is expressed in the male genital tract in a region‐specific manner, and this activity may have a role in initiation of sperm motility acquired during its transit through the epididymis in mammals. © 1994 Wiley‐Liss, Inc.
Attachment of the ascidian sperm surface egg receptor N‐acetylglucosaminidase to the cell membrane
Authors: Downey John C. , Lambert Charles C. 
Published: February 2005

AbstractAscidian sperm bind to vitelline coat N‐acetylglucosamine groups of the egg bvia sperm surface N‐acetylglucosaminidase. This sperm surface egg receptor remains anchored throughout penetration. Localization to the sperm surface was verified by biotinylation of intact sperm followed by solubilization in Triton X‐100 and binding to streptavidin agarose. The enzyme was determined to be an integral membrane protein as judged by resistance to release by KI and high pH. Linkage of the enzyme to the sperm surface was probed through differential solubilization followed by measuring released enzymatic activity with a fluorogenic substrate. Nonionic detergents released 90% of the activity. Proteases released about 40%. No activity was released by a phosphatidyl–inositol specific phospholipase C. This finding, combined with the similarity of release level by all the detergents, including triton X‐114 phase separation experiment. This observation, coupled with the finding of release by nonionic detergents, suggests that the protein is hydrophilic once released from the membrane. Thus, although clearly an integral membrane protein, the enzyme has limited bydrophobicity such as would be present in a single transmembrane sequence or extensive glycosylation. © 1994 Wiley‐Liss, Inc.
Cumulus cells secrete a meiosi‐inducing substance by stimulation with forskolin and dibutyric cyclic adenosine monophosphate
Authors: Guoliang Xia , Byskov Anne Grete , Andersen Claus Yding 
Published: February 2005

AbstractThe role of the cumulus cells in initiating the resumption of meiosis after exposure to forskolin and dbcAMP was studied in the mouse. The resumption of meiosis was monitored by the percentage of germinal vesicle breakdown (GVBD) and polar body formation (PB). The cumulus‐enclosed oocytes (CEO) and denuded oocytes (DO) were cultured with and without hypoxanthine (HX) in the culture medium.Three types of experiments were performed: (1) Effect of forskolin on spontaneous resumption of meiosis, i.e. cultures without HX, and two experiments in which HX is present throughout the culture: (2) Effect of transient exposure to forskolin or dibutyric‐cyclic adenosinemonophosphate (dbcAMP) on GVBD prior to continued culture without forskolin or dbcAMP (oocyte priming). (3) Priming of CEO with forskolin for 2 hr, separation of cumulus cells and oocytes, followed by coculture of rejoined cumulus cells and oocytes, or coculture of the cumulus cells and new, unprimed DO.(1) Forskolin inhibited a spontaneous resumption of meiosis in a dose‐dependent manner during the first 5 hr of culturing. After 22 hr all controls and CEO resumed meiosis, whereas only half of the DO did.(2) At least 1 hr of priming the CEO with forskolin is needed to induce GVBD and PB formation, but forskolin inhibited the resumption of meiosis when present for 24 hr. Similar results were obtained with a high concentration of dbcAMP.(3) A separation and rejoining of oocytes and cumulus cells after priming induced the resumption of meiosis in a significantly greater number of oocytes than in the control oocytes which were not primed. The GVBD of unstimulated DO also increased significantly when cocultured with cumulus cells from primed CEO. The percentage of GVBD in unprimed DO and in DO isolated from primed CEO was the same.We suggest that within 1–2 hr, forskolin and cAMP stimulate cumulus cells to produce a diffusible meiosis‐inducing substance which overcomes HX‐inhibition and induces oocyte maturation, including both GVBD and PB formation. The CEO must be primed for more than 2 hr before the resumption of meiosis in DO isolated from such CEO is induced. Oocyte‐cumulus connections are crucial as far as initiating the production of a meiosis‐inducing substance is concerned. Oocyte‐cumulus connections are not needed for transferring this substance to the oocyte. © 1994 Wiley‐Liss, Inc.
Role of fibroblast growth factors as inducing agents in early embryonic development
Authors: Slack Jonathan 
Published: February 2005

AbstractTo assess the potential role of a molecule in development we need to know three things: 1) what are the biological activities of the molecule, 2) what is its expression pattern, and 3) what are the consequences of removing it from the embryo?In the case of the FGF family in Xenopus embryos we have quite a lot of information about all three questions. Most members of the family can induce mesoderm from isolated animal caps, thus mimicking the natural “ventral vegetal” inducing signal operative in the blastula. This activity can be exerted on isolated, disaggregated cells and does not involve a change in division rate. When overexpressed from injected mRNA, the activity of FGFs depends largely on whether or not they possess a signal sequence, showing the importance of secretion in the inductive process. In addition to the mesoderm‐inducing activity, there are effects of overexpression on whole embryos which lead to a suppression of anterior structures.Three types of FGF have so far been cloned from Xenopus: direct homologs of each of the mammalian types FGF‐2 and FGF‐3, and eFGF (“embryonic FGF”), which is equidistant in sequence from mammalian FGF‐4 and FGF‐6. Attempts to find homologs of mammalian FGF‐5 and FGF‐7 in Xenopus have proved unsuccessful. All three types of Xenopus FGF are expressed in early development. FGF‐2 and eFGF are present in the oocyte and fertilized egg, and are thus both available at the time of mesoderm induction. FGF‐3 and eFGF are both expressed from the embryonic genome during gastrulation and concentrated in the forming mesoderm. FGF‐2 is expressed from the embryonic genome during neurulation in the brain, and a little later in the branchial arch mesenchyme and in the forming myotomes. These expression patterns suggest that there are several functions for the FGFs.The most successful strategy for inhibition of the FGF system has been the use of a dominant negative receptor construct introduced by Kirschner and colleagues. Overexpression of this construct can abolish the FGF responsiveness of animal caps. In whole embryos, the absence of FGF signaling causes a reduction, although not a total ablation, of mesoderm formation. There is also a severe effect on axis formation in which formation of the posterior parts is reduced consequent on an inhibition of invagination and elongation of the dorsal mesoderm.Thus, the present evidence suggests that the FGF system contributes to, although is not solely responsible for, mesoderm induction in vivo. It is also necessary for normal gastrulation movements, particularly in the dorsal mesoderm, and is likely to have several later functions, particularly in development of the central nervous system and the myotomes. © 1994 Wiley‐Liss, Inc.
Structure of the bovine follicle‐stimulating hormone receptor complementary DNA and expression in bovine tissues
Authors: Houde Alain , Lambert Anick , Silversides David W. , Lussier Jacques G. , Saumande Jean 
Published: February 2005

AbstractWe report the complementary DNA structure obtained by reverse transcription and polymerase chain reaction amplification encoding the complete amino acid sequence for the bovine follicle‐stimulating hormone receptor (bFSHr). The deduced amino acid sequence for the cDNA revealed a mature polypeptide consisting of 678 amino acids (theoretical weight of 76.4 kDa) and a 17 amino acid putative leading signal peptide. The receptor consists of a large NH2‐terminal extracellular membrane domain of 349 aa with 3 potential N‐linked glycosylation sites, a transmembrane domain (264 aa) consisting of 7 putative membrane spanning segments, and an intracytoplasmic COOH‐terminal domain (65 aa). Four potential phosphorylation sites were found in the transmembrane domain and the COOH‐terminal domain. The amino acid sequence is 97%, 89%, and 88% homologous to the ovine, human, and rat FSHr respectively, with complete conservation of the 22 cysteine residues in the whole protein and the 3 N‐linked glycosylation sites on the extracellular membrane domain. Northern blot analysis of total mRNA in bovine tissues revealed a major mRNA transcript of 2.55 kb for the bFSHr in the ovary without corpus luteum, and in the testis. No expression was found in other tissues analyzed. Total RNA from bovine granulosa cells collected from pregnant mare serum gonadotropin (PMSG)‐treated prepubertal heifers showed 2 major mRNA transcripts of 6.8 and 2.55 kb, and 3 minor transcripts of 3.8, 3.3, and 1.6 kb. Bovine granulosa cells cultured with porcine FSH (0, 2, 10 ng/ml) for 4 days showed a decrease in the steady state level of the FSHr mRNA. This decrease was shown to be independent of the size of the transcript. Therefore, expression of the bovine FSHr by bovine granulosa cells is downregulated at the message level when exposed to constant concentrations of FSH. ©1994 Wiley‐Liss, Inc.
Production of germline chimeric chickens, with high transmission rate of donor‐derived gametes, produced by transfer of primordial germ cells
Authors: Naito Mitsuru , Tajima Atsushi , Yasuda Yoshiaki , Kuwana Takashi 
Published: February 2005

AbstractGermline chimeric chickens were produced by transfer of primordial germ cells from White Leghorn to Barred Plymouth Rock, and vice versa. Blood was collected from stage 13–15 embryos and primordial germ cells were concentrated by Ficoll density gradient centrifugation. Approximately 200 primordial germ cells were injected into the bloodstream through the dorsal aorta of stage 14–15 recipient embryos from which blood had been drawn via the dorsal aorta prior to the injection. Intact embryos were also prepared as recipients for White Leghorns only. The manipulated embryos were cultured in recipient eggshells until hatching. Germline chimerism of the chickens reaching maturity was examined by mating them with Barred Plymouth Rocks and donor‐derived offspring were identified based on their feather color. The efficiency of production of germline chimeras was 95% (19/20). When primordial germ cells were transferred from White Leghorn to Barred Plymouth Rock, the average frequency of donor‐derived offspring was 81% for three male chimeras (96% for one female chimera), and it was ∼3.5 times higher for transfer in the opposite direction (23% for 6 male chimeras). Removing blood from recipient embryos prior to primordial germ cell injection enhanced the frequency of donor‐derived offspring by 10% in resulting male chimeras. Male chimeras produced donor‐derived offspring more frequently (∼3.8 times) than female chimeras. Increases, decreases, or no changes were observed in the frequency of donor‐derived offspring from the germline chimeras with increasing age. Male to female ratio of the offspring derived from the donor primordial germ cells did not deviate significantly in male and female chimeras, suggesting that primordial germ cells that have different sex from recipient embryos could not differentiate into functional gametes. The technique for primordial germ cell transfer employed in this experiment is simple to perform and resulted in the efficient production of germline chimeras with high transmission rates of donor‐derived gametes. This system provides a powerful tool for avian embryo manipulation. © 1994 Wiley‐Liss, Inc.
Follicular wall maintains meiotic arrest in bovine oocytes cultured in vitro
Authors: A.M. De Loos F. , Zeinstra E. , M. Bevers M. 
Published: February 2005

AbstractCumulus oocyte complexes (COCs) were cocultured with parts of the follicular wall. Coculture conditions were such that the COCs were 1) in continuous contact with the follicular wall (FWC), 2) separated from the follicular wall at collection but in contact with it during culture (FWR), and 3) separated from the follicular wall, but cultured in its vicinity (FWNR). Oocytes cultured for 24 hr under FWC conditions maintained the germinal vesicle stage. Under FWR conditions the germinal vesicle stage was not maintained, but an arrest at metaphase I of meiosis occurred in mostof the oocytes. When COCs were cultured in the vicinity of the follicular wall (FWNR), meiosis was resumed and similar numbers of oocytes progressed to metaphase II of meiosis as compared to cultures of COCs without coculture with parts of the follicular wall. When COCs were isolated from the follicular wall after 24 hr of culture and additionally cultured for another 24 hr, the oocytes showed the same capability of resuming meiosis as fresh, isolated cumulus oocyte complexes.It is concluded that maintenance of contact with the follicular wall is necessary to maintain meiotic arrest. When COCs restore a physical contact with the follicular wall during culture, an arrest at metaphase I occurs. © 1994 Wiley‐Liss, Inc.
T‐cell functional regions of the human IL‐3 proximal promoter
Authors: R. Ryan G. , A. Vadas M. , F. Shannon M. 
Published: February 2005

AbstractThe human interleukin‐3 (IL‐3) gene is expressed almost exclusively in activated T cells. Its expression is regulated at both the transcriptional and post‐transcriptional level. We have previously shown that treatment of Jurkat T cells with phytohemaglutinin (PHA) and the phorbol ester, PMA, activated transcription initiation from the lL‐3 gene. To define the regions of the gene required for transcription activation, we generated a series of reporter constructs containing different regions of the IL‐3 gene 5′ and 3′flanking sequences. Both positive and negative regulatory elements were identified in the proximal 5′ flanking region of the lL‐3 gene. The promoter region between –173 and –60 contained the strongest activating elements. The transcription factor AP‐1 could bind to this positive activator region of the promoter. We also examined the function of the lL‐3 CK‐1/CK‐2 elements that are present in many cytokine genes and found that they acted as a repressor of basal level expression when cloned upstream of a heterologous promoter but were also inducible by PMA/PHA. © 1994 Wiley‐Liss, Inc.
Leukaemia inhibitory factor and the regulation of pre‐implantation development of the mammalian embryo
Authors: L. Stewart Colin 
Published: February 2005

AbstractThis paper reviews the evidence that certain growth factors, particularily leukaemia inhibitory factor (LIF), play a crucial role in regulating the development of the pre‐implantation mammalian embryo. LIF was originally implicated in regulating the early development of the mouse embryo because it inhibited the differentiation of embryonic stem (ES) cells, pluripotential cells derived from the inner cell mass of the blastocyst. Subsequent studies on its role in vivo revealed, surprisingly, that it is essential for the growth rather than the differentiation of the blastocyst. In vivo, overtly normal blastocysts can be produced in a LIF‐deficient environment that are capable of forming viable fertile adults. However, in the absence of LIF, they fail to implant and enter into a state resembling that exhibited by blastocysts undergoing delayed implantation, which is characterized by a cessation of cell proliferation. This failure to implant occurs because the principle sites of LIF production are the endometrial glands of the uterus. These synthesize and secrete LIF at implantation, with LIF synthesis essential for implantation. Preliminary evidence indicates that LIF synthesis is required both by the uterus for it to undergo decidualization and by the blastocyst for implantation. These data indicate that the maternal environment plays a crucial role in the development and growth of the pre‐implantation embryo, by supplying factors that regulate these processes in the embryo. © 1994 Wiley‐Liss, Inc.
Relationships between biochemical markers for residual sperm cytoplasm, reactive oxygen species generation, and the presence of leukocytes and precursor germ cells in human sperm suspensions
Authors: Aitken John , Buckingham Donna , Krausz Csilla 
Published: February 2005

AbstractIn this study, we have examined the relationship between creatine phosphokinase (CPK), a biochemical measure of human sperm quality (Huszar et al., 1988 a, b, 1990; Huszar and Vigue, 1994), and a marker for the presence of residual cytoplasm in human spermatozoa, glucose‐6‐phosphate dehydrogenase (G6PDH). We then determined whether the diagnostic potential of these enzymes was related to the capacity of the sperm suspensions to generate reactive oxygen species (ROS) and/or the presence of leukocytes and precursor germ cells. Across the data set as a whole, G6PDH and CPK were highly correlated with each other and, to a lesser extent, with the generation of ROS. Contamination of the sperm suspensions with leukocytes might have contributed to these associations, since the presence of such cells was also significantly correlated with CPK, G6PDH, and ROS. However, even after the leukocytes had been carefully removed, G6PDH was still highly correlated with CPK (r= 0.794), indicating that both criteria were providing similar information on the cytosolic component of human sperm suspensions. In the absence of leukocyte contamination, CPK and G6PDH activities were also correlated with the presence of precursor germ cells, and this association may, in part, explain the diagnostic value of these criteria. An additional component of their prognostic value may be reflected in the statistically significant association observed between G6PDH activity and ROS generation. A possible mechanism for such an association is suggested, which should be amenable to experimental verification. © 1994 Wiley‐Liss, Inc.
Putative rat sperm lipid‐binding protein: Isolation and partial characterization
Authors: Xu Wenhao , Moore Alison , M. Ensrud Kathy , W. Hamilton David , L. Pryor Jon 
Published: February 2005

AbstractPrevious work has identified a prominent 22–24‐kD protein that is present in rat male reproductive tissues, including epididymis and testis (Brooks, 1985; Jones and Brown, 1987; Moore et al., 1987). Using a monoclonal antibody (designated mAb‐B109) against this 24‐kD antigen (referred to as B109), we have isolated the protein using a combination of chromatofocusing and electroelution from SDS–PAGE gels, and reverse phase HPLC. B109 (pl = 4.8) is amino‐terminal blocked. To obtain internal amino acid sequences, the isolated protein was cleaved either with cyanogen bromide in 70% formic acid or with TLCK‐treated chymotrypsin. With cyanogen bromide treatment, two peptides, 17.8 kD and 11.9 kD, were isolated and partial amino acid sequences obtained. Chymotryptic peptides were isolated by reverse‐phase HPLC and two were chosen for sequence analysis A computer search for sequence homology through the protein identification resource (PIR) matched B109 to a basic 21‐kD cytosolic protein (pl = 7.4) found in bovine brain (> 80% homology). When peptide sequence differences obtained in the present study were substituted into the 21‐kD cytosolic protein sequence obtained from the PIR using IntelligeneticsTM software, the calculated pl dropped from 7.4 to 5.8, suggesting that pl differences between the bovine and rat molecules are the result of amino acid substitutions in the testis protein and not tissue‐specific posttranslational processing. It has been postulated that the 21‐kD bovine brain protein is associated with phospholipid transport, although the function of B109 is unknown. © 1994 Wiley‐Liss, Inc.
Vitronectin is an intrinsic protein of human spermatozoa released during the acrosome reaction
Authors: M. Fusi Francesco , Lorenzetti I. , Mangili F. , C. Herr John , J. Freemerman Alex , Gailit James , A. Bronson Richard 
Published: February 2005

AbstractEvidence has been presented that oolemmal integrins and their ligands on spermatozoa may play a role in gamete interactions leading to fertilization. We previously demonstrated that vitronectin (Vn) could be extracted from fresh human spermatozoa and detected in Western blots, and Vn was observed on the surface of living, capacitated sperm by indirect immunofluorescence. In the present experiments, messenger RNA encoding Vn was detected in human testis poly (A+) RNA using Northern analysis, and Vn was localized within the acrosomal region of ejaculated sperm by immunoperoxidase and immunofluorescence staining. During the acrosome reaction, induced in capacitated spermatoza by lonomycin, Vn was released into the medium in a calcium‐dependent manner. Vn appears to be a specific product of intratesticular spermatozoa that is secreted during the acrosome reaction. These findings suggest that Vn is positioned to play a strategic role in gamete interactions leading to fertilization. © Wiley‐Liss, Inc.