bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholesterol and polyunsaturated acid enriched diet: Effect on kinetics of the acrosome reaction in rabbit spermatozoa
Authors: Diaz‐Fontdevila Marina , Bustos‐Obregon Eduardo 
Published: February 2005

AbstractIn this study we examined the effect of cholesterol (Diet 2), cholesterol and fish oil (FO) polyunsaturated acid (Diet 3), and polyunsaturated acid (Diet 4) enriched diets upon the acrosome reaction (AR) of New Zealand White rabbit spermatozoa. Male rabbits fed with cholesterol alone or with FO increased their cholesterol and LDL‐cholesterol serum levels after 15 days of diet. Ten semen samples were obtained after 2 months of diet. Our results suggest that hypercholesterolemia and hypertriglyceridemia in male rabbits could produce a decreased capacity of sperm AR after 4 h (0%, 0%, and 60% lower than the control), 6 h (0%, 68%, and 44%), or 8 h (58%, 52%, and 32%) of incubation in capacitating medium. Another set of experiments were made with lysophosphatidylcholine (LPC), 80 μg/ml, and the same pattern of AR was seen. Nevertheless, the high cholesterol and total lipids (TL) levels in serum did not affect the cholesterol levels in seminal plasma (SP) but affect the SP total lipids. The diminished capacity of rabbit sperm to undergo the AR was not reverted by in vitro incubation with the Shinitsky medium for cholesterol depletion (MDC). These results indirectly suggest that the cholesterol/phospholipid ratio in hypercholesterolemic sperm is similar to that of controls and are in agreement with preliminary studies made in our laboratory that evidenced the same cholesterol/ phospholipid ratio in rabbit sperm from hypercholesterolemic animals than from controls. These findings and the higher sterol‐filipin complex in the acrosomal membrane of hypercholesterolemic animals compared to controls reported by Diaz‐Fontdevila et al. (1992) could suggest that in this study different sperm membrane lipid domains induced by the hypercholesterolemia are the cause of the AR kinetics modification. © 1993 Wiley‐Liss, Inc.
Binding of anti‐H‐Y monoclonal antibodies to separated X and Y chromosome bearing porcine and bovine sperm
Authors: Hendriksen Peter J. M. , Tieman Marion , Van Der Lende Tette , Johnson Lawrence A. 
Published: February 2005

AbstractStudies designed to answer the question whether or not H‐Y antigen is preferentially expressed on Y chromosome bearing sperm have resulted in conflicting results. This is probably due to the absence of reliable methods for estimating the percentage of X and Y chromosome bearing sperm in fractions, enriched or depleted for H‐Y antigen positive sperm. In recent years a reliable method for separating X and Y chromosome bearing sperm has been published. With this method, separation is achieved by using a flow cytometer/cell sorter, which detects differences in DNA content. This technique provided the first opportunity for testing anti‐H‐Y antibody binding to fractions enriched for X and Y chromosme bearing sperm, directly. A total of 7 anti‐H‐Y monoclonal antibodies were tested using sorted porcine sperm and in one experiment also sorted bovine sperm. All monoclonal antibodies bound only a fraction of the sperm (20 to 50%). However, no difference in binding to the X and Y sperm enriched fractions was found. Therefore, the present experiments do not yield evidence that H‐Y antigen is preferentially expressed in Y chromosome bearing sperm. © 1993 Wiley‐Liss, Inc.
Phospholipids of rabbit and bull sperm membranes: Structural order parameter and steady‐state fluorescence anistropy of membranes and membrane leaflets
Authors: Hinkovska‐Galcheva Vania , Srivastava Prakash N. 
Published: February 2005

AbstractThe plasma (PM), outer acrosomal (OAM), and inner acrosomal membranes (IAM) were isolated from rabbit and bull spermatozoa and the major phospholipids characterized. Choline‐containing phospholipids, phosphatidylcholine (PC) and sphingomyelin (SM), constituted more than 60% of the total phospholipids (TPL) in all membranes of both species. Approximately more than 50% of PC in membrane preparations contained some form of ether linkage. Compared to OAM and IAM, cholesterol to phospholipid molar ratio was highest in PM of both species. Contrarily, protein to phospholipid ratio for PM was lowest compared to other membranes. The sphingomyelin to phosphatidylcholine ratio increased in the direction from PM to OAM to IAM. The hydrophobic fluorescent probe 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) was used to examine both the steady‐state fluorescence anisotropy parameters and structural order parameter SDPH. The data showed higher rigidity in rabbit spermatozoa compared to bull spermatozoa (SDPH = 0.7582 and SDPH = 0.7326). In both species OAM had higher rigidity compared to the other two membranes (SDPH(OAM) = 0.7809, SDPH(PM) = 0.7308, and SDPH(IAM) = 0.7481 for bull; SDPH(OAM) = 0.8091, SDPH(PM)= 0.7857, and SDPH(IAM) = 0.7663 for rabbit). The inner leaflets of bull and rabbit spermatozoal membranes had significantly higher rigidity than the outer leaflets (for inner leaflet: rabbit‐SDPH(PM) = 0.8391, SDPH(OAM) = 0.8149, and SDPH(IAM) = 0.7675; bull‐SDPH(PM) = 0.8000, SDPH(OAM) = 0.7990, and SDPH(IAM) = 0.7990, and for outer leaflet: rabbit‐SDPH(PM) = 0.7021, SDPH(OAM) = 0.7145, and SDPH(IAM) = 0.6867; bull‐SDPH(PM) = 0.6986, SDPH(OAM) = 0.5980, and SDPH(IAM) = 0.7388). © 1993 Wiley‐Liss, Inc.
Temporal expression of tissue inhibitors of metalloproteinases in mouse reproductive tissues during gestation
Authors: Waterhouse Paul , Denhardt David T. , Khokha Rama 
Published: February 2005

AbstractTissue inhibitors of metalloproteinases (TIMPs) appear to play an important regulatory role in tissue remodelling and invasion by malignant cells. Since pregnancy involves morphological changes in existing maternal tissues, as well as a strictly controlled invasion by fetal trophoblasts, we have examined the temporal expression of TIMP‐1, TIMP‐2, and specific metalloproteinases in the mouse uterus, decidua, placenta, amnion, and ovaries throughout gestation by examining mRNA levels on northern and slot blots. Maximal levels of TIMP‐1 mRNA were observed from day 6 to day 10 in the uterus, decidua, and placenta. In clear contrast to the early burst of TIMP‐1 mRNA accumulation, the level of TIMP‐2 mRNA increased steadily throughout gestation in the uterus, decidua, and amnion, while in the placenta it showed a sevenfold increase after day 14. In amnion, TIMP‐1 was induced specifically on day 18. Interestingly, the normally high level of TIMP‐1 mRNA seen in the ovaries of virgin mice was low during gestation, until day 18 and postpartum, when a sixfold increase over the levels in virgin ovary was observed. In contrast, ovarian TIMP‐2 mRNA showed a marginal increase during gestation. The temporal pattern of 72 kDa gelatinase type A followed that of TIMP‐2 in the decidua and ovary. Stromelysin‐2 mRNA was detected at term only in ovary and decidua. Our data show that the temporal accumulation of TIMP‐1 and TIMP‐2 mRNA is precisely coordinated in each of the tissue compartments and is independently regulated during the in vivo remodelling of reproductive tissues in gestation. The peak of TIMP‐1 mRNA levels in the uterus, decidua, and placenta at midgestation is associated with the most invasive period of embryo development. © 1993 Wiley‐Liss, Inc.
Immunoelectron microscope localization of snRNP, hnRNP, and ribosomal proteins in mouse spermatogenesis
Authors: Biggiogera M. , Von Schack M.‐L. , Martin T. E. , Gordon J. , Müller M. , Fakan S. 
Published: February 2005

AbstractWe have studied the ultrastructural distribution of heterogeneous nuclear ribonucleoproteins (hnRNPs), small nuclear ribonucleoproteins (snRNPs), and ribosomal proteins during mouse spermatogenesis and spermiogenesis by means of specific antibodies and immunocytochemistry.All the above components were detectable from primary spermatocytes until the spermatid elongation phase, when the RNA synthetic activity is known to cease. Ribosomal protein (P1/P2 and L7) labeling disappeared as early as during the acrosome phase, and nucleoli were no longer labeled even during the cap phase. The nucleoplasmic structures labeled with the different anti‐nucleoplasmic RNP immunoprobes corresponded, until the acrosome phase, to those previously observed as targets of the same antibodies in the nucleoplasm of somatic cell nuclei. Clusters of interchromatin granules of spermatocyte and early spermatid nuclei exhibit some labeling for hnRNP when compared with nuclei of Sertoli cells or previously analyzed liver or tissue culture cells, where these structural constituents usually remain weakly labeled or unlabeled.In spermatids in step 10, another type of nuclear granule, resembling perichromatin granules, but occurring in aggregates, can be observed. These structural constituents were labeled with antibodies recognizing nucleoplasmic snRNP antigens and therefore suggesting a non‐nucleolar origin of these granules.Finally, we have observed nucleoplasmic areas of fibrogranular material, occurring only in primary spermatocytes. These components were labeled with anti‐ribosomal protein antibodies but did not contain either hnRNPs or snRNPs. © 1993 Wiley‐Liss, Inc.
Biotinylation of proteins on the surface of zona‐free mouse oocytes
Authors: Flaherty Sean P. , Swann Nicholas J. 
Published: February 2005

AbstractIn this study, we have labelled proteins on the surface of unfertilized, zona‐free mouse oocytes using a nonisotopic biotinylation procedure. The zona pellucida was weakened by brief incubation in chymotrypsin and removed by mechanical pipetting through a narrow‐bore glass pipette. Surface proteins were labelled using sulfo‐NHS‐biotin (sulfosuccinimidobiotin), a water‐soluble, membrane‐impermeable biotinylation reagent. The distribution of biotinylated proteins on the oocyte surface was assessed by fluorescence microscopy using streptavidin–FITC. Bright fluorescence was noted on the surface of the oocyte, except in a circular region overlying the meiotic spindle where the fluorescence was weak or absent. The intensity of fluorescence was markedly reduced by incubation of biotinylated oocytes in trypsin (1 mg/ml) or chymotrypsin (2 mg/ml), and in vitro fertilization experiments showed that biotinylation did not compromise the fertilizability of the oocytes. The biotinylated proteins were separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) and analyzed by Western blotting using streptavidin–HRP and enhanced chemiluminescence (ECL) detection. The most prominent biotinylated proteins were of Mr 82 and 69 kD, but other major proteins of Mr 93, 78, 61, 52, 49, 40, 28, and 22 kD were detected, as well as 14 minor proteins of Mr 18–100 kD. The major bands could be detected in fewer than 50 oocytes. This biotinylation procedure is fast, versatile and sensitive, and it is therefore an excellent tool for studying proteins exposed on the surface of mammalian oocytes and embryos. © 1993 Wiley‐Liss, Inc.
Multiple effects of seminal plasma on the acrosome reaction of human sperm
Authors: Cross Nicholas L. 
Published: February 2005

AbstractMammalian sperm do not respond to inducers of the acrosome reaction immediately after ejaculation. They become responsive after they are removed from seminal plasma and incubated in an appropriate medium. We tested the effects of seminal plasma on the development of acrosomal responsiveness. Washed human sperm incubated 24 hr in vitro with 10% (v/v) seminal plasma did not complete an acrosome reaction when exposed to human follicular fluid, progesterone, or ionomycin. Seminal plasma did not reduce sperm viability or motility. Electron microscopy of sperm incubated 24 hr with 5% seminal plasma and then treated with progesterone revealed no sign of membrane fusion or other changes that are associated with the acrosome reaction. During a 12‐hr incubation, seminal plasma was 50% effective at inhibiting the acrosomal response to progesterone when diluted 821 ± 112 foid (mean ±SD, n = 3). Sperm that were incubated with seminal plasma for 24 hr and then washed free of the seminal plasma became acrosomally responsive over the following 24 hr, at a rate similar to that of sperm not incubated with seminal plasma in vitro. When sperm were incubated 6 hr without seminal plasma and then seminal plasma was added, the sperm population transiently became more responsive to progesterone, and then became unresponsive. During incubation in vitro, the ability of sperm to have an augmented response to a mixture of seminal plasma plus progesterone developed slightly earlier and more rapidly than ability to respond to progesterone alone. When sperm were incubated 24 hr without seminal plasma, a few acrosome reacted in response to the addition of seminal plasma alone. Therefore, depending on how it is applied, seminal plasma can prevent or reverse the development of acrosomal responsiveness, and it can enhance or induce the acrosome reaction. © 1993 Wiley‐Liss, Inc.
Phylogeny of the insulin‐like growth factors (IGFS) and receptors: A molecular approach
Authors: LeRoith Derek , Kavsan Vadim M. , Koval Anatolii P. , Roberts Charles T. 
Published: February 2005

AbstractThe IGFs (IGF‐I and IGF‐II) are essential for normal mammalian growth and development. Their actions are mediated primarily by their interactions with the type I IGF receptor (IGF‐I receptor), a transmembrane tyrosine kinase. The ligands and the IGF‐I receptor are structurally related to insulin and to the insulin receptor, respectively. Analysis of evolutionary conservation has often provided insights into essential regions of molecules such as hormones and their receptors. The genes for insulin and IGFs have been partially characterized in a number of vertebrate species extending evolutionarily from humans as far back as fish. The sequences of the exons encoding the mature insulin and IGF peptides are highly conserved among vertebrate species, and IGF‐I‐Iike molecules are found in species whose origins extend back as much as 550 million years. The insulin receptor is also highly conserved in vertebrate species, and an insulinreceptor‐like molecule has been characterized in Drosophila. In contrast, IGF‐I receptors have only been characterized in mammalian species and partially studied in Xenopus, in which the tyrosine kinase domain is highly conserved. Studies are presently being undertaken to analyze in more detail the regulation of the genes encoding this important family of growth factors and the structure/function relationships in the gene products themselves. © 1993 Wiley‐Liss, Inc.
Functional analysis of the human IGF‐I gene promoters
Authors: Steenbergh P. H. , Jansen E. , Van Schaik F. M. A. , Sussenbach J. S. 
Published: February 2005

AbstractThe two putative promoter regions of the human insulin‐like growth factor‐I (IGF‐I) gene, located upstream of the two alternatively used leader exons 1 and 2, were tested for promoter activity in transient transfection assays. Both regions were shown to possess promoter activity. The results further indicate cell‐type‐specific regulation of the activities of the two promoters in endogenously IGF‐I producing human cell lines of different origin. © 1993 Wiley‐Liss, Inc.
Identification of an antisense transcript from the IGF‐II locus in mouse
Authors: Rivkin Michael , Rosen Kenneth M. , Villa‐Komaroff Lydia 
Published: February 2005

AbstractWe have identified a novel antisense RNA transcribed from the insulin‐like growth factor‐II (IGF‐II) locus in mouse. This transcript was identified using probes derived from cloned genomic DNA lying between the insulin II locus and the IGF‐II locus. S1 protection assays confirmed that this transcript is transcribed from the strand complementary to the stand encoding IGF‐II. A 3.75 kb RNA was consistently detected on northern analysis of mouse tissue using different randomly primed DNA probes generated from this region. S1 nuclease protection analysis identified three exons contained in the transcript. Developmental northern analysis was performed using RNA from embryonic (E) and postnatal (P) tissues of E10, E13, E18, P1, P4, P10, and adult mice. The antisense RNA was most abundant in E13 and E18 mouse and was present in greatest amounts in skull, skeletal muscle, cardiac muscle, and placenta. No signal for this RNA was detected after the fourth day of life in any tissue studied. © 1993 Wiley‐Liss, Inc.
Expression of IGF ligand and receptor genes during preimplantation mammalian development
Authors: Schultz Gilbert A. , Hahnel Ann , Arcellana‐Panlilio Mayi , Wang Liangsu , Goubau Sabine , Watson Andrew , Harvey Mark 
Published: February 2005

AbstractThe temporal patterns of expression of genes encoding insulin‐like growth factor (IGF) ligands and receptors during very early development have been investigated in several laboratories in several different mammalian species. Both reverse transcription‐polymerase chain reaction (RT‐PCR) and immunocytochemical techniques have been used to identify the time of appearance of gene transcripts or end‐products. In preimplantation mouse embryos, IGF‐II ligand and receptor gene activity is detectable as early as at the two‐cell stage, the time when transcription from the embryonic genome is activated, but receptors for insulin and IGF‐I are not detectable until the compacted eight‐cell stage. Transcripts for insulin or IGF‐I are not detectable in preimplantation mouse embryos, although the ligands are present in the reproductive tract. The pattern of IGF gene expression is not, however, identical in all mammalian species. In cow embryos, for example, transcripts for IGF‐I and IGF‐II ligands and receptors and insulin receptors have been detected at all stages of preimplantation development from mature oocyte to blastocyst (Watson et al., 1992). Attempts to quantitate transcript abundance in these early embryos are in progress in our laboratory. In the preimplantation mouse embryo, transcripts for several different IGF‐binding proteins (IGFBP‐2, ‐3, ‐4, and ‐6) have been detected by RTPCR procedures. In addition, transcripts for IGFBPs have been identified in RNA derived from cumulus cells, the ovary, the oviduct, the uterus, and the decidua. These findings suggest that the interactions of IGF ligands and receptors in preimplantation development might, indeed, be modulated by IGFBPs. Approaches to function of IGFs in preimplantation embryos have involved analysis of the stimulatory effects on metabolism and cell division when IGFs are added exogenously to embryos in culture in simple defined medium (for example, see Harvey and Kaye, 1991) or observations in the reduction in rate of development following interference with IGF expression (see Rappolee et al., 1992). In general, members of the insulin and IGF gene family of polypeptides have been shown to lead to an enhahancement of development in vitro in both laboratory and domestic mammalian species. © 1993 Wiley‐Liss, Inc.
Functions of the IGFs in early mammalian development
Authors: Heyner Susan , Shi Cong‐Zhu , Garside William T. , Smith Robert M. 
Published: February 2005

AbstractThe identification of growth factors and/or receptors produced by mammalian embryos or present in the maternal reproductive tract is of basic interest, as well as having practical application. Early studies established that receptors binding insulin and the insulin‐like growth factors (IGFs) are expressed by preimplantation mouse embryos. These studies have been confirmed at the molecular level using RT‐PCR techniques. In addition, high resolution electron microscopy has shown that insulin is internalized by the cells of the blastocyst stage mouse embryo, and that immunologically intact insulin is detectable in the cells of the trophectoderm and inner cell mass. Similar studies with gold labelled IGF‐I have shown that this ligand is also bound and internalized by mouse blastocysts. However, although all blastocysts express receptors that bind IGF‐I on the basolateral cell surface of the trophectoderm, only 30% exhibit apically located receptors. In order to elucidate the functions of IGFs in early mouse development, we are in the process of constructing protein databases for embryos at the eight‐cell and blastocyst stage. By the use of the database, it should prove possible to elucidate targets of growth factor action. © 1993 Wiley‐Liss, Inc.
Acrosome reaction of boar spermatozoa in homologous in vitro fertilization
Authors: Vázquez J. M. , Martínez E. , Roca J. , Coy P. , Pastor L. M. 
Published: February 2005

AbstractEjaculated spermatozoa from four different boars were used to evaluate the acrosome reaction during in vitro fertilization with homologous ovulated oocytes. The acrosome reaction was assessed according to a peroxidase‐labeling peanut agglutinin method and a triple‐stain technique. An increase in the proportion of living sperm with reacted acrosomes was observed after preincubation and 2 hr of coincubation (P < 0.05). The percentage of true acrosome‐reacted sperm remained reasonably constant throughout coincubation. In vitro penetration rates of oocytes varied among boars, but no relationship was found between fertilization rates of oocytes and maximum percentages of acrosome reacted living sperm. © 1993 Wiley‐Liss, Inc.
The abundant 19‐kilodalton protein associated with human sperm nuclei that is related to seminal plasma α‐inhibins
Authors: Zalensky Andrei O. , Yau Peter , Breneman John W. , Bradbury E. Morton 
Published: February 2005

AbstractA basic protein with a relative molecular mass of 19 kDa has been identified and isolated to purity from sonication‐resistant, partially demembranized human sperm nuclei. Several criteria prove that this is the unique sperm‐specific protein, which was previously thought to be a sperm/testis histone. Partial primary structure sequencing demonstrates homologies with human seminal α‐inhibins and semenogelin. From the sequence and Western‐blotting data with antibodies against basic seminal inhibin‐like peptide, we propose that this 19‐kD protein is a product of 52‐kDa semenogelin processing. The 19‐kDa protein was not found among seminal plasma proteins and may be protected from further cleavage into inhibin‐like peptides by its association with the sperm head Immunofluorescence data indicate its localization in the nuclear periphery, with preferential concentration at the acrosome calyx boundary. © 1993 Wiley‐Liss, Inc.
Actin polymerization in boar spermatozoa: Fertilization is reduced with use of cytochalasin D
Authors: Castellani‐Ceresa L. , Mattioli M. , Radaelli G. , Barboni B. , Brivio M. F. 
Published: February 2005

AbstractThe aggregational state of actin in boar spermatozoa after capacitation and the acrosome reaction has been examined by several methods. In vitro fertilization (IVF) experiments were conducted in the presence and absence of cytochalasin D (CD) to evaluate the role of actin polymerization in the events of fertilization. The fertilizing capacity was very high in controls, but, when CD (an inhibitor of the polymerization of actin) was added to the capacitation medium, there was a marked decrease in the fertilizing capacity of the boar spermatozoa. There was a further decrease when CD was present during both capacitation and fertilization processes. In addition to the IVF tests, biochemical and immunoelectron microscopic methods were used to analyze the state of aggregation of actin in boar spermatozoa after capacitation, and the acrosome reaction. By immunoelectron microscopy with a phalloidin probe, there were no gold particles, indicating the presence of F‐actin on boar sperm heads capacitated and acrosome‐reacted in media containing CD. By sodium dodecyl sulfate‐polyacrylamide gel electrophoresis there were differences in NP‐40 solubility, reflecting actin polymerization, between CD‐treated and untreated sperm. These results suggest that actin polymerizes during capacitation and the acrosome reaction and that this polymerization is essential to the fertilization process. © 1993 Wiley‐Liss, Inc.