bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capacitation, acrosome reaction, and egg penetration by canine spermatozoa in a simple defined medium
Authors: Mahi Cherrie Ann , Yanagimachi Ryuzo 
Published: February 2005

AbstractA defined medium (CCM) is described in which washed ejaculated canine spermatozoa can be induced to undergo capacitation and the acrosome reaction, and to penetrate corona‐free eggs in vitro. The composition of the medium is similar to other Krebs‐Ringer's bicarbonate buffered media except for the absence of magnesium and adjustments in the concentration of NaHCO3, glucose, and albumin. The concentration of NaCI is adjusted to maintain the osmolality at approximately 300 mOsm, and the pH is 7.8 under 5% CO2 in air. This pH was found more favorable for the occurrence of the acrosome reaction than the lower pH (7.4) of media with more usual bicarbonate concentrations. Calcium ions are essential not only for the occurrence of the acrosome reaction of canine spermatozoa, but also for their motility. Potassium ions are apparently necessary for the process of sperm‐egg fusion following zona penetration. When CCM was compared with two other media, it allowed the best combination of good rates for acrosome reaction (46%), motility (83%), and zona penetration (71%). Sperm‐egg fusion also occurred. The requirements for capacitation of canine spermatozoa are compared with those of some other species.
Heat labile activating substance for ornithine decarboxylase activity in sea urchin eggs
Authors: Kusunoki Shinichiro , Yasumasu Ikuo 
Published: February 2005

AbstractIn sea urchin eggs, the activity of ornithine decarboxylase (ODC) [ E C 4.1.1.17] is detectable only in the particulate fraction yielded by centrifuging egg homogenates at 10,000g for 30 minutes. ODC activity in the particulate fraction isolated from fertilized eggs is higher than that from unferti‐lized eggs. ODC activity in the particulate fraction isolated from either unfertilized or fertilized eggs is enhanced by adding the supernatant fraction obtained by centrifugation at 105,000g for two hours. Heating this supernatant at 70°C for 15 minutes results In complete loss of the stimulating capacity for ODC activity. Sea urchin eggs seem to contain heat labile activating substance(s) for ODC activity. The substance does not pass through the ultrafiltration membrane Diafro UM–10. Only eggs and unhatched embryos, in which mitosis occurs frequently, contain the activating substance. In the presence of the activating substance, Ca2+enhanced ODC activity.
The aflagellate spermatozoon of ophryotrocha: A line of evolution of fertilization among polychaetes
Authors: Berruti Giovanna , Ferraguti Marco , Donin Carla Lora Lamia 
Published: February 2005

AbstractThe spermatozoa of the annelid polychaete Ophryotrocha have been examined under the electron microscope. They show some primitive features (scarcely condensed nucleus, pores in the nuclear envelope, unmodified mitochondria) and are aflagellate. This aberrant structure is related to a very specialized type of external fertilization in which the spermatozoa are ejaculated close to the eggs.
Sperm glycoproteins of the boar, bull, rabbit, and ram: II. Surface glycoproteins and free acidic groups
Authors: Fléchon Jacques‐Edmond 
Published: February 2005

AbstractEjaculated spermatozoa of boars, bulls, rabbits, and rams were embedded in glycolmethacrylate and thin sections stained with phosphotungstic acid at low pH in order to observe the distribution of glycoproteins of the plasma membrane. Colloidal iron hydroxide was also used to detect the free acidic groups present on the sperm surface. Species‐specific patterns of localizations of glycoproteins and linked negative charges were observed. The distribution was sometimes homogeneous as in bull, but generally heterogeneous in the other species. The significance of the results on sperm surface components and the practical interest to know their normal distribution are discussed.
The spermatogenesis of crustaceans: The external morphology of the spermatozoa of heterocypris incongruens, ramdohr (Ostracoda)
Authors: López‐Camps J. , Fontarnau R. , Bargalló R. 
Published: February 2005

AbstractIn various papers on the original spermatozoon of the Ostracoda, its helicoidal disposition has been indicated as the principle characteristic of this gamete, at cell structure level as well as in its external morphology. Through a combined study with scanning electron microscope (SEM) and transmission electron microscope (TEM), we have been able to establish the corresponding relationship between the cell architecture and the spermatozoon's external morphology. In the case of Heterocypris incongruens, the helicoidal relief of the gamete's external surface along the greatest part of its length, is the result of the twisting and undulating of a structure derived from the nucleus' external membrane, endoplasmic reticulum, and Golgi apparatus, called “feather‐like organelle.” In keeping with the shape of this surface relief, the spermatozoon can be divided into three regions: An anterior one with a corkscrew form, a middle one showing a relief in the form of a screw with four threads, and a posterior or tail one without helicoidal relief. Finally, we discuss the different criteria existing on the possible orientation of this spermatozoon when it moves, as well as the functional advantages that the possession of a filiform, helicoidal, and mobile gamete represents.
Sperm penetration in vitro into ovarian and tubal oocytes from mice of the inbred KE and C57 strains
Authors: Kaleta Elżbieta 
Published: February 2005

AbstractThe method of in vitro fertilization was applied to test a previous suggestion that the lowered fertilizability of the tubal oocytes of female KE strain mice and the high resistance of their zona pellucida to proteolytic enzymes, are due to the premature cortical reaction taking place near the time of ovulation. Therefore higher fertilizability of ovarian oocytes is expected.The effectiveness of F1 hybrid sperm penetration into ovarian and tubal KE oocytes confirmed these assumptions. The ovarian KE oocytes recovered 9–10 hours after administration of human chorionic gonadotropin (HCG) showed significantly higher penetrability (70–83%) than did the tubal oocytes recovered 12 hours after HCG (about 50%) and 14–16 hours after HCG (20%).Similar results were obtained with C57 oocytes. Sperm penetration into ovarian oocytes (10 hours after HCG) was much more effective (67%) than into tubal oocytes (18%); this finding correlated with more rapid zona dissolution by chymotrypsin. On the basis of these results one might speculate that premature cortical reaction takes place also in the C57 strain.
Endogenous phosphorylated proteins during maturation of Xenopus laevis oocytes
Authors: Bellé R. , Boyer J. , Ozon R. 
Published: February 2005

AbstractDuring the course of maturation of Xenopus laevis oocyte a burst of phosphorylation occurs around germinal vesicle breakdown. At the same time a relative drop in a unique phosphoprotein (protein I; mot wt ∼40,000) is observed. Enucleation of [32P] labeled oocytes has shown the cytoplasmic localization of protein I. Methylxanthines and cholera toxin, which inhibit progesterone‐induced maturation, block the burst of phosphorylation and do not change the amount or the distribution of [32P] phosphoproteins.
Effects of chimaerism for two T/t complex mutations on sperm function
Authors: Papaioannou Virginia E. , Artzt Karen , Dooher Gerald B. , Bennett Dorothea 
Published: February 2005

AbstractMouse chimaeras produced by aggregation of embryos heterozygous for two different recessive mutations at the T/t complex have been analyzed by breeding to explore the basis for the phenomena of male transmission ratio distortion and sterility associated with these genes. Whereas males of genotype tw2/tw5 are always sterile, male chimaeras of the type +/tw2 ⟷ +/tw5 are normally fertile; furthermore, they transmit each t mutation to the same very high extent seen in ordinary (+/t) heterozygotes. Since spermatogenic cells derived from either the +/tw2 and +/tw5 genotypes thus function quite independently of one another in mosaic testes, it can be concluded that sterility, and presumably distorted transmission ratio as well, depends on specific interactions between T/t alleles in diploid spermatogenic cells or their individual meiotic descendants.
Motile properties and localization of contractile proteins in the spermatozoon of discoglossus pictus
Authors: Campanella C. , Gabbiani G. 
Published: February 2005

AbstractEjaculated spermatozoa from Discoglossus pictus are grouped in bundles, where they are embedded in a network of interwoven threads. Their heads and tails move when exposed to the outermost egg jelly layer, when the bundles are spread across a glass slide or a poly‐L‐lysine‐coated polystyrene tissue culture dish. While moving, single spermatozoa emerge from the bundle and eventually become able to fuse with egg.Spermatozoa were studied by means of immunofluorescent staining, using specific antibodies against actin, myosin, and tubulin, and by means of electron microscopy. Antiactin antibodies stain both the heads and the ridge (which contains the axoneme) of the tail's undulating membrane. Antimyosin antibodies stain the head segment covered by the acrosome cap, and antitubulin antibodies stain the axoneme. The presence of actin and myosin in the spermatozoon head may provide the molecular basis for a cytoskeletal and/or a contractile system which could be involved in the motion sequence as well as subsequent steps of fertilization.
On the integrity of sperm DNA
Authors: Young R. J. 
Published: February 2005

AbstractEjaculated rabbit spermatozoa washed with buffer prior to decondensation by Triton X‐100 and dithiothreitol were good templates for DNA synthesis by Escherichia coli DNA polymerase. This result agrees with the observations of Zirkin and Chang [1977], and implies that the sperm DNA is nicked. Template activity, however, was reduced if spermatozoa were extensively washed before decondensation, and if DNase inhibitors EDTA or Na2SO4 were present during decondensation. Template activity was also low if decondensation was induced with DNase inhibitors thioglycollic acid, Na2SO3 or sodium dodecylsulphate and dithiothreitol instead of with Triton X‐100 and dithiothreitol. Calf thymus DNA was completely degraded when incubated with rabbit seminal plasma or buffer‐washed spermatozoa, but much less degradation was observed if EDTA, Na2SO4, thioglycollic acid, Na2SO3 or sodium dodecylsulphate were also present, or if spermatozoa were extensively washed with buffer. Centrifugation of spermatozoa through 2.05 M sucrose completely removed contaminating DNase, and such spermatozoa were inactive as DNA templates after decondensation. The DNA template activity of swollen rabbit sperm nuclei thus parallels the activity of a contaminating seminal plasma DNase. This suggest that the nicks in sperm DNA enabling it to act as a template for DNA synthesis were generated by the DNase during decondensation and thus are not a natural structural feature of the DNA. The presence of breaks in the DNA of decondensed buffer‐washed spermatozoa (DNase contaminated) was confirmed by their incorporation of phosphate from [γ−32 P] ATP in the presence of the enzyme polynucleotide kinase. These spermatozoa were found to contain as few as two breaks/mole of DNA, but sucrose‐washed spermatozoa (DNase free) were free of breaks. The possible use of this enzymic procedure for the assessment of sperm genome damage and the evaluation of the quality of a sperm population are discussed.
Effects of Bonellin on fertilization and cleavage of the eggs of the sea urchin, sphaerechinus granularis
Authors: De Nicola Giudici M. , Cariello L. , Zanetti L. 
Published: February 2005

AbstractWe have studied the structural changes occurring in the eggs of the sea urchin Sphaerechinus granularis treated with bonellin, the green pigment of the sea worm Bonellia viridis, which is responsible for the masculinization of the larva of this animal. The two major targets of bonellin appear to be the cortical structures and the nuclear membrane, while the mitochondria do not appear to be affected. As a result of bonellin treatment, cleavage is prevented while nuclear divisions proceed. The possibility is discussed that the alteration of the cortical structures may interfere with the assembly of the surface microfilaments and hence with the formation of the cleavage furrows.
Fertilization induced release of glycogen from bound state in sea urchin eggs
Authors: Hindo Akiya , Yasumasu Ikuo 
Published: February 2005

AbstractGlycogen in sea urchin eggs is found in both the precipitate and the supernatant fractions obtained by adding perchloric acid to the egg homogenate. Glycogen in the acid‐insoluble fraction is apparently protein‐bound (bound glycogen) while the acid‐extractable form (free glycogen) seems to bind with less protein. The greatest amount of bound glycogen is found in the particulate fraction obtained by centrifugation of the egg homogenate at 10,000g for 30 minutes. The supernatant fraction obtained by centrifugation at 105,000g for two hours contained the largest amount of free glycogen of all the fractions obtained. The bound glycogen decreases and the free glycogen increases markedly following fertilization, while the total level of glycogen does not change. The glycogen release from the bound state occurs in vitro and the rate of release is higher in fertilized eggs than in unfertilized eggs. Polyamines (putrecine, spermidine, and spermine) cause an increase in the rate of glycogen release in the egg homogenate. cAMP, AMP, and ADP exert no effect on glycogen release in vitro, whereas ATP slightly enhances the rate of glycogen release. Na+ and K+ hardly accelerate the rate of glycogen release, and divalent cations, such as Ca2+ and Mg2+, cause an increase in the rate of glycogen release.
Ultrastructure of the spermatozoid in Halimeda tuna (chlorophyceae)
Authors: Gori P. 
Published: February 2005

AbstractThe mature Halimeda tuna spermatozoid was studied under the electron microscope. It is pear‐shaped and biflagellate. The nucleus is an uncondensed structure except for a few opaque (chromatin) aggregations and shows a rounded profile. The endoplasmic reticulum is a rather well‐developed system of rough cisternae engaged in synthesis and storage of proteins. Free ribosomes are numerous. A large mitochondrial apparatus shaped like a horseshoe lies in the anterior gamete region. Only one single plastid is found, and it exhibits a deeply indented outline, a partially structured matrix, osmiophilic globules, and three to four starch grains. The axoneme pattern is 9 + 2. B tubules show septate lumina. A peculiar structure provided with a three‐layered shell covering materials of varying electrondensity lies on the upper surface of both basal bodies. The flagellar root system exhibits a cruciate pattern and sets having an inconstant number of microtubules – ie, three, four, or five.
Artificial fertilization of gametes from the South African clawed frog, Xenopus laevis
Authors: Hollinger T. G. , Corton G. L. 
Published: February 2005

AbstractA reproducible and effective method for fertilization eggs of Xenopus laevis was developed based of systematic manipulation of environmental factors. The effects of varying concentrations of individual components of a fertilization medium were tested by measuring jelly swelling, sperm motility, and sperm longevity. Results were used to develop an improved medium for fertilization, consisting of 41.25 mM NaCl, 1.25 mM KCl, 0.25 mM CaCl2, 0.0625 mM MgCl2, 0.5 mM Na2HPO4, 2.5 mM HEPES, 1.9 mM NaOH, final pH(2°) 7.8.
The effect of progesterone and estradiol on gonadotropin – induced oocyte maturation in isolated ovarian follicles from mice
Authors: Tyler J. P. P. , Collins W. P. 
Published: February 2005

AbstractOvaries from pubertal mice were dissected into fragments containing 1–4 antral follicles, which were cultured on the surface of a chemistry defined medium. After 17–20 hrs oocytes were released from the cultured follicles and their meiotic status recorded. In the presence or absence of exogenous gonadotropins oocytes in these cultures behaved meiotically as expected if they had been studied in the intact animal. Media containing 100 μM of progesterone for the duration of the culture period caused atresia of the oocytes, and although the addition of gonadotropins reduced this necrosis they did not induce the resumption of meiosis. The meiotic stimulating effect of gonadotropins was also inhibited if progesterone was present in the culture media for the first 3 hours only. Estradiol (100 μM) similarly inhibited the meiotic inducing action of gonadotropins when left in the medium for the duration of culture, but had no effect when administrated for a shorter period. The results from this model system, would indicate that the meiotic‐initiating action of gonadotropins can be modulated by exposure to progesterone and estradiol.
Progesterone secretion by the post‐ovulatory rat cumulus oophorus
Authors: Sherizly Israelit , Kraicer P. F. 
Published: February 2005

AbstractThis study was designed to determine whether cumulus oophorus cells secrete progesterone. Immature PMS‐primed, hCG‐treated rats were used. Their cumuli were isolated from pre‐ovulatory (no hCG) and peri‐ovulatory (after hCG) follicles, and from post‐ovulatory oviducal ampullae. Treatment with hCG increased progesterone secretion by almost two‐and‐one‐half‐fold. It was speculated that the cumulus oophorus secretion of progesterone modifies the accumulation of fluid in the ampulla, thus providing the medium in which fertilization takes place.
Role of cumulus cells for rat oocyte maturation and metabolism
Authors: Magnusson Claes 
Published: February 2005

AbstractOocytes collected from immature PMSG‐treated rats on the morning of proestrus were allowed to mature in culture either surrounded by their cumulus cells or after denudation. It was found that the time course of oocyte nuclear maturation was similar whether the cumulus cells were present or not. The oxygen consumption of noncultured oocytes was 0.12 nl/hr/oocyte and increased by 40% after four to eight hours in culture with intact cumulus. Respiration of oocytes cultured without cumulus remained constant throughout the culture, except for a transient decrease after four hours.It is concluted that the cumulus cells do not affect the spontaneous nuclear maturation in vitro, but that the metabolism in oocytes cultured with intact cumulus is different from that of cultured denuded oocytes. Furthermore, it appears that the rise in oocyte oxygen consumption is not a prerequisite for nucler maturation.
Immunocytochemical studies on the zona pellucida of cow blastocysts
Authors: Fléchon J.‐E. , Gwatkin R. B. L. 
Published: February 2005

AbstractLabeling of the zona pellucida of cow blastocysts with zona‐specific anti‐serum shows that antigenicity is unaffected by abnormal cleavage, in vitro culture, or frozen storage. The uniform labeling in thin sections indicates that the zona pellucida is homogeneous antigenically. Heavier labeling of the inner and outer surfaces of the zona pellucida in thick sections appers to be due to greater porosity of these regions, in which the zona material becomes highly dispersed, or even partly solubilized, thereby permitting the formation of an antigen‐antibody matrix.
Actin filaments and mitochondrial movement in vertebrate spermiogenesis
Authors: Baccetti B. , Bigliardi E. , Burrini A. G. , Pallini V. 
Published: February 2005

AbstractThe presence of actin filaments around mitochondria during vertebrate spermiogenesis was demonstrated by immunofluorescence and immuno‐electron microscopy and by heavy meromyosin decoration. The presence of actin is supposed to be related to mitochondrial rearrangements occurring in the spermatid stage.
The crater defect in boar spermatozoa: A correlative study with transmission electron microscopy, scanning electron microscopy, and light microscopy
Authors: Truitt‐Gibert Anne J. , Johnson L. A. 
Published: February 2005

AbstractNuclear vacuoles resembling the “crater defect” described in bull spermatozoa were observed in 14 boars. Both the incidence of the defect and semen quality were monitored with phase contrast microscopy over a three‐month period. The percentages of cratered spermatozoa varied widely both among boars and in ejaculates from the same boar taken on different days. The presence of cratered spermatozoa at a level of 5% or more appeared to be associated with low semen quality. The defect was studied with scanning and transmission electron microscopy and was found to consist of nuclear invaginations, about 0.5 μm in diameter, containing some scanty amorphous electron‐dense material. In boars showing a high incidence of spermatozoa with crater defects, abnormalities of the acrosome and perforatorium were common.
Identification of a rabbit sperm autoantigen as a Ricinus communis I receptor
Authors: O'Rand Michael G. , Romrell Lynn J. 
Published: February 2005

AbstractThe isolated rabbit sperm plasma membrane autoantigen RSA‐1 has been identified as a receptor for the lectin, Ricinus communis I (RCA). Using purified RSA‐1 labeled with125 I, the autoantigen was shown to bind to RCA affinity columns and the eluted fraction bound to specific anti‐RSA‐1 alloantiserum immunoadsorbent columns.
Comparative ultrastructure of the yolk material in preimplantation stages of the hamster, mouse, and rat embryos
Authors: Nilsson B. Ove 
Published: February 2005

AbstractYolk material of preimplanation stages of embryos of the hamster, mouse, and rat were examined by a standardized electron microscopical procedure. The material was encountered as fibrils, scattered more or less densely in the cytoplasm. In the hamster, the material was present in large masses and the fibrils had a chain‐like appearance when cut longitudinally. The ultrastructure of the fibrils was compatible with a helical pattern. The fibrils had a width of about 40 nm and the pitch (the axial distance of the repeating unit) was about 30 nm. In the mouse, the yolk material was dispersed in the cytoplasm forming small plaque‐like groups. Also, in this species the fibrils were chain‐like but smaller than in the hamster. The fibrils were often closely situated, resulting in images with varying crystalline appearances. In the rat, the yolk appeared as light areas occupying a substantial part of the cytoplasm. The fibrils in the yolk plaques were sparse and diffusely outlined. They were thinner than the fibrils of the mouse‐yolk material, did not display any helical pattern at the resolution used, but showed a periodicity.