bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane potential, pH and the activation of surf clam oocytes
Authors: Finkel Toren , Wolf Don P. 
Published: February 2005

AbstractUnfertilized oocytes of the surf clam, Spisula solidissima, have resting membrane potentials of −18 ± 7 mV (n = 20). Within five seconds of sperm addition, an electrophysiologically detectable response was apparent, which was characterized by a rapid and prolonged depolarrization depolarization followed four to five minutes post‐insemination by the beginning of the beginning of a steady hyperpolarization to approximatelv −70 mV. This final hyperpolarization was completed within ten minutes of sperm addition. The initial rapid depolarization following insemination may result from a transient increase in sodium conductance, and it may be crucial in preventing polyspermy, since the degree of polyspermy in Spisula oocytes was sensitive to external sodium ion concentrations. Evidence was obtained that changes in intracellular pH are essential for oocvte activation. Using germinal vesical breakdown (GVB) as a marker for activation, it was shown that agents that raise intracellular pH (ammonia and procaine) induced GVB, whereas agents that lower intracellular pH pH (Na‐acetate or Na‐propionate seawater) inhibited GVB.
Partial activation of sea‐urchin eggs by bonellin
Authors: Cariello Lucio , de Nicola Giudici Marina , Zanetti Laura 
Published: February 2005

AbstractWe here describe further studies on the action of bonellin on sea‐urchin eggs. Bonellin brings about Some of the changes that are known to occur in the egg upon fertilization. In particular, it appears to cause the increased rate of incorporation of amino acids into proteins, the increase of the voltage noise, and the exocytosis of some of the cortical granules. A comparison with the effect of ammonia is discussed.
Membrane differentiations in spermatozoa of the squid, Loligo pealeii
Authors: Olson Gary E. , Linck Richard W. 
Published: February 2005

AbstractRegional differences in the structure of the plasma membrane and acrosome membrane of squid spermatozoa were studied by freeze‐fracture and thin section electron microscopy. In regions of close apposition the plasma membrane and acrosome membrane are adjoined to one another by regularly spaced linkages. These linkage sites, overlie a set of fibers located at the inner face of the acrosomal membrane. The acrosomal fibers terminate in a layer of granular material located at the base of the acrosome. Detergent treatment of sperm releases the fibers and granular material as an interconnected complex. Freeze‐fracture replicas reveal a random arrangement of intramembranous particles in the plasma membrane over the sperm head and linear aggregates of intramembranous particles in the acrosomal membrane. Several regional differences in the structure of the flagellar plasma membrane are present. The thickness of the glycocalyx is progressively reduced distally along the flagellum. Freeze‐fracture replicas show evenly spaced linear arrays of intramembranous particles which extend parallel t o the flagellar long axis. Examination of spermatozoa extracted to disrupt flagellar geometry suggest that the dense fiber‐doublet microtubule complexes are attached to the plasma membrane. The possible functional role of these membrane differentiations and their relationship t o membrane structures in mammalian spermatozoa are discussed.
Optimization of culture conditions for the formation of sperm cells in pollen tubes of tradescantia
Authors: Lafleur Gloria J. , Gross Amy E. , Mascarenhas Joseph P. 
Published: February 2005

AbstractA culture medium and culture conditions are described that enable generative cell division and sperm formation to occur in a large proportion (greater than 70%) of the pollen tubes of Tradescantia paludosa within six to eight hours of culture of pollen. The nature of the nitrogen source, speed of shaking, and ratio of pollen to medium are important parameters in determining the extent of sperm formation. Addition of the plant hormones indole acetic acid, gibberellic acid, and kinetin to the growth medium does not influence generative cell division.
Kinematics of human spermatozoa
Authors: David G. , Serres C. , Jouannet P. 
Published: February 2005

AbstractA microcinematographic (50 f/s) study was performed on motile human spermatozoa. Eighty percent were found to have a linear trajectory and a pseudo‐sinusoidal head displacement pattern. Throughout their progression, the spermatozoa periodically rotated on their longitudinal axis at a frequency equal to that of flagellar wave formation. These waves were found always to begin on the same side of the cell and to propagate in the flattened plane of the head until the moment of rotation. At this time the wave had reached a point near the middle of the flagellum. Beyond this point, the flagellum moves out of the plane of the head. Different variables used to characterize the movement of spermatozoa included the velocity of progression, amplitude and velocity of head displacement, frequency of rotation, wave amplitude, and propagation velocity of the flagellar wave. Among these variables, it was the propagation velocity of the wave that was found to be best correlated with the velocity of spermatozoan progression. This flagellar wave exhibited two stages, one of initiation and one of propagation.
The assessment of human sperm morphology in surface replica preparations for transmission electron microscopy
Authors: Mortimer David 
Published: February 2005

AbstractHuman spermatozoa were treated with the detergents Hyamine 2389, Triton X‐100, or sodium dodecyl sulphate (SDS) and surface replica preparations and Papanicolaou‐stained smears made. From the ultrastructural studies it was found that Hyamine caused a dissolution of the plasmalemma to reveal the outer acrosomal membrane that was often absent over the anterior cap region; whereas Triton, in addition, caused severe damage to the entire acrosome. Treatment with SDS rapidly cleaved the tails from the majority of the spermatozoa, stripped the plasmalemma from both the head and tail regions of the cells, and also removed the whole of the outer acrosomal membrane plus most of the acrosomal contents. However, when viewed in the Papanicolaou‐stained preparations, the spermatozoa were all of apparently normal morphology.These studies make it clear that some caution must be used when interpreting human sperm morphology assessments made under the light microscope. While it is not suggested that the more involved technique of surface replication should be used in routine semen analyses, it does represent a valuable technique for use with research material.
Inhibition of fertilization in cattle by passive immunization with anti‐zona pellucida serum
Authors: Tsunoda Y. , Soma T. , Sugie T. 
Published: February 2005

AbstractPassive immunization with antiserum prepared against isolated bovine zonae pellucidae inhibited fertilization in the cow. The minimum dosage of antiserum (titer 27 by immunofluorescence) required for complete inhibition was 2 ml/kg of body weight.
Vitelline layer lytic activity in sperm extracts of sea urchin, Hemicentrotus pulcherrimus
Authors: Yamada Yuji , Aketa Kenji 
Published: February 2005

AbstractA factor which dissolves the vitelline layer was extracted from sperm of the sea urchin, Hemicentrotus pulcherrimus. Turbidity of the suspension was reduced when isolated vitelline layers were mixed with this sperm factor. When the mixture was subjected to SDS polyacrylamide gel electrophoresis, some of the protein bands of the vitelline layer were seen to be missing. The lytic activity of the factor was heat labile, completely inhibited by L‐1‐tosyl‐amide‐2‐phenyl‐ethylchloromethyl ketone and partially inhibited by soybean trypsin inhibitor. Chymotrypsin activity was detected, but not trypsin, arylsulfatase, or glycosidase. These results suggest that a chymotrypsin‐like enzyme participates in lysis of the vitelline layer by the fertilizing spermatozoon.
The effects of carnitine, glycerylphosphorylcholine, caffeine, and egg yolk on the motility of rat epididymal spermatozoa
Authors: Turner T. T. , Giles R. D. 
Published: February 2005

AbstractExperiments were performed to further the understanding of epididymal processes involved in the acquisition of sperm motility. Samples of luminal contents were collected by micropuncture from four regions of the rat epididymis. These samples were incubated in various diluents to observe the effects of the diluents on sperm motility. Consonant with previous reports, 40 mM glycerylphosphorylcholine (GPC) and 60 mM DL‐carnitine reduced overall motility scores of cauda epididymidal spermatozoa but did not prevent normal initiation of motility. Additionally, control sperm cells and cells treated with carnitine could reinitiate full motility after becoming immotile. Spermatozoa treated with GPC could not reinitiate motility. The sperm cells in our system thus react to GPC and carnitine in fundamentally different ways, the exact nature of which remains to be determined.Spermatozoa from the distal caput epididymidis evidenced high motility scores when diluted in a 5% egg yolk + 10 mM caffeine diluent. It was demonstrated, however, that the subjective appearance of full motility in these immature cells was not supported by actual progressive motility as measured in an assay of linear distance traveled. It was concluded that neither 10 mM caffeine, 5% egg yolk, nor their combination was sufficient to induce progressive motility in immature rat spermatozoa.
Acid‐extracted nuclear proteins and ultrastructure of human sperm chromatin as revealed by differential extraction with urea, mercaptoethanol, and salt
Authors: Tanphaichitr Nongnuj , Sobhon Prasert , Chalermisarachai Panpaka , Patilantakarnkool Malinee 
Published: February 2005

AbstractBasic proteins were differentially extracted from the purified heads of ejaculated human sperm by successive treatment with (1) 1% Triton X‐100, 1% mercaptoethanol (ME); (2) 8 M urea, 1% ME; (3) 8 M urea, 1% ME, 0.2 M NaCl; and (4) 8 M urea, 1% ME, 0.6 M NaCl. Nonhistones were extracted in the first, second, and third treatments; histones, in the second and third; and most of the protamines, in the fourth, together with DNA. Corresponding electro microscopic studies of the sperm pellets after each treatment suggest that the nucleoprotamines are discrete portions of chromatin which are organized in the form of long thick cords and oval bodies of about 400–550 Å in diameter interlinked with very thin strands of fibers about 20–50 Å thick, which could represent the naked DNA depleted of its constituent histones.
Radio‐iodination of plasma membrane polypeptides from isolated mouse spermatogenic cells
Authors: Millette Clarke F. , Moulding Christopher T. 
Published: February 2005

AbstractCell surface polypeptides of mouse pachytene spermatocytes and round spermatids (steps 1–8) have been iodinated using 1,2,3,6,tetracholoro‐3α, 6α‐diphenylglycouril (IODOGEN). Labeled proteins have been assayed using two‐dimensional polyacrylamide electrophoresis and radioautography. Purified plasma membranes, prepared from both spermatocytes and spermatids after the iodination of intact cells, exhibit 25–30 polypeptides which label reproducibly. No significant qualitative differences are noted in the labeled polypeptide map obtained from each of the purified cell types. Iodinated proteins range in molecular weight from greater than 100k daltons to approximately 40k daltons. The isoelectric points of labeled constituents range from pI 5.7 to 7.2. Three polypeptides represent the major iodinated species: p 94/5.8, p 75/5.9, and p 53/7.1. Comparison with total plasma membrane constituents assayed using Coomassie brilliant blue indicates that many of the radioactively labeled proteins are not present in quantities sufficient to allow ready detection without isotopic techniques. As a result, many of the proteins identified autoradiographically represent newly described surface components of mouse pachytene spermatocytes and round spermatids. The preparation of purified plasma membrane fractions prior to electrophoresis ensures that all iodinated species are in fact cell surface components. Furthermore, experiments designed to assess the vectorial nature of the IODOGEN‐catalyzed labeling procedure suggest that most, if not all, of the iodinated species are exposed on the external side of the cell plasma membrane. Therefore, these studies have (1) identified hitherto unrecognized plasma membrane components of mouse pachytene spermatocytes and round spermatids and (2) provided the first available biochemical data concerning the molecular orientation of particular proteins in the surface membranes of developing mouse spermatogenic cells.
Reaction of sperm with egg‐derived hydrogen peroxide helps prevent polyspermy during fertilization in the sea urchin
Authors: Boldt Jeffrey , Schuel Herbert , Schuel Regina , Dandekar Pramila V. , Troll Walter 
Published: February 2005

AbstractRecent evidence suggests roles for egg derived hydrogen peroxide (H2O2) and ovoperoxidase (secreted by cortical granules) in both fertilization envelope hardening and the block to polyspermy in sea urchins. Strongylocentrotus purpuratus eggs were found to release H2O2 during the cortical reaction at fertilization. Treatment of sperm with equivalent concentrations of H2O2 resulted in a rapid loss of sperm fertilizing ability. Attempts were made to induce polyspermy by utilizing ovoperoxidase inhibitors at concentrations known to inhibit fertilization envelope hardening. Eggs fertilized in phenylhydrazine became polyspermic, while 3‐amino‐1,2,4‐triazole‐treated eggs did not. These data suggested that a sperm peroxidase might be involved in preventing polyspermy. This hypothesis was tested by the addition of phenylhydrazine or 3‐amino‐1,2,4‐trizaole to H2O2‐treated sperm. Phenylhydrazine acted to protect sperm fertility from H2O2, while 3‐amino‐1,2,4‐triazole increased the adverse effect of H2O2. Simultaneous addition of both inhibitors to sperm incubated in H2O2 gave an intermediate value of sperm fertility. These data indicate that (1) H2O2 generated by sea urchin eggs during the cortical reaction at fertilization is used for two separate processes, fertilization envelope hardening and the prevention of polyspermy; (2) ovoperoxidase is probably not involved in preventing polyspermy; and (3) egg‐derived H2O2 reacts directly with sperm enzymes to prevent polyspermy. The phenylhydrazine‐sensitive enzyme in the sperm is probably a peroxidase that acts to inactivate sperm, while the 3‐amino‐1,2,4‐triazolesensitive enzyme is probably a catalase which protects sperm from H2O2. This hypothesis is consistent with model experiments on horseradish peroxidase and bovine liver catalase.
Production, characterization, and use of ionophore‐induced, calcium‐dependent acrosome reaction in ram spermatozoa
Authors: Shams‐Borhan Gabriele , Harrison R. A. P. 
Published: February 2005

AbstractA system has been developed for inducing a calcium‐dependent acrosome reaction in ram spermatozoa in vitro using the calcium ionophore A23187. The resultant reaction is accompanied by release of the acrosomal enzymes hyaluronidase and acrosin, but there is no release of the cytoplasmic enzyme glucose 6‐phosphate isomerase. In any given cell, the visible acrosome reaction apparently takes place rapidly, but there is a variable delay before the reaction occurs. Under optimum conditions, about 90% of treated spermatozoa show an acrosome reaction within one hour.Preincubation of the spermatozoa with the proteinase inhibitors p‐amino‐benzamidine or p‐nitrophenylguanidinobenzoate allows two stages of the reaction to be distinguished ultrastructurally, a membrane fusion stage followed by a dispersal of the acrosomal matrix. In the presence of the inhibitors, the first stage is delayed but is completed within 1 hour, whereas the second remains largely incomplete.In the presence of calcium, ionophore concentrations which induce an acrosome reaction abolish sperm motility rapidly and completely. However, by adding serum albumin shortly after addition of ionophore, motility can be preserved while the acrosome reaction occurs as usual; the motility pattern observed under these conditions is of the “whip‐lash” or “activated” type.Although the motile ionophore‐treated spermatozoa were unsuccessful at penetrating normal mature sheep oocytes in vitro, they were able to penetrate zona‐free oocytes, after which swelling and decondensation of the sperm head took place.
Enrichment of primary pachytene spermatocytes from the human testis
Authors: Shepherd Robert W. , Millette Clarke F. , DeWolf William C. 
Published: February 2005

AbstractNormal adult human testis has been separated using a combination of mechanical and enzymatic procedures to yield a suspension of viable single cells. The predominant cell types comprising this suspension are as follows: primary pachytene spermatocytes (7% of total cells), round spermatids (17%), residual bodies and condensing spermatids (31%), and Leydig cells (15%). Separated human germ cells viewed by Nomarski differential interference microscopy closely resemble mouse spermatogenic cells in relative size and appearance. Isolation of an enriched population of human pachytene spermatocytes has been achieved using unit gravity sedimentation (STA‐PUT) according to protocols originally developed for murine tissue. Pachytene cells are enriched to 75% and are contaminated only with Leydig cells and binucleated spermatid symplasts. Ultrastructural examination of isolated human pachytene spermatocytes indicates that these cells, as well as isolated round spermatids, exhibit a normal in situ morphology. Spermatocytes, for example, show numerous synaptonemal complexes, nuclear pores, annulate lamellae, and dictyosome‐like saccules. Round spermatids after isolation exhibit peripheral mitochondria, annulate lamellae, developing acrosomes, and other morphological features characteristic of early spermiogenesis. Therefore, enriched populations of human spermatogenic cells seem suitable for analysis using immunofluorescent, autoradiographic, or serological methods. In particular, isolated human spermatocytes should be useful for the analysis of molecular events involved in meiosis and should facilitate investigations concerning the pathophysiology of certain human infertility conditions.
Evidence for nonmuscle myosin in bovine ejaculated spermatozoa
Authors: Tamblyn Toby M. 
Published: February 2005

AbstractMammalian spermatozoa contain nonmuscle actin and many of the components of regulatory systems thought to be involved in nonmuscle actin‐myosin function. An actin‐stimulated adenosine triphosphate hydrolase (ATPase) activity has been fractionated from bovine ejaculated spermatozoa by immobilized‐actin affinity chromatography. The actinstimulated ATPase activity has a specific activity (0.04 ± 0.02 mM phosphate released/min/mg protein) similar to nonmuscle myosins from other mammalian cells and tissues, but it does not have appreciable K+‐EDTA ATPase activity. The sperm actin‐myosin may function in sperm morphogenesis in the seminiferous tubule, in capacitated spermatozoa undergoing an acrosome reaction, or in decondensation of the sperm nucleus after fertilization.
Stimulation of hamster sperm capacitation and acrosome reaction in vitro by glucose and lactate and inhibition by the glycolytic inhibitor α‐chlorohydrin
Authors: Dravland Eric , Meizel Stanley 
Published: February 2005

AbstractStudies were made of the effects of D(+)‐glucose, L‐lactate and pyruvate on in vitro capacitation and acrosome reactions (AR) of hamster sperm using a more “defined” medium that that used in previous similar studies. In the absence of glucose or lactate, sperm underwent very few AR and activation (whiplash‐like motility characteristic of capacitated hamster sperm) was reduced compared to those events in sperm preincubated in the presence of glucose plus lactate plus pyruvate. Glucose and pyruvate supported more AR than glucose alone, but less than glucose, lactate, and pyruvate. The glycolytic inhibitor α‐chlorohydrin (10 μm) inhibited AR by 50% and reduced activation by less. When glucose was added to sperm incubated 2 hr with pyruvate and lactate, the number of AR observed after 4 hr was the same as that obtained when glucose was present throughout the incubation. When glucose was added after 3.5 hr, AR were delayed for 1 hr and lower numbers of sperm underwent AR. In the presence of lactate and pyruvate, 0.38 mM glucose was able to support activation and AR as well as 3.24 mM glucose. These results indicate that exogenous glucose and lactate are necessary for in vitro capacitation and AR of hamster sperm; only low levels of exogenous glucose are required; exogenous glucose is not required during the first 2 hr of capacitation; and glycolytic activity is necessary for capacitation and the AR.
Cross fertilization between sea urchin eggs and oyster spermatozoa
Authors: Osanai Kenzi , Kyozuka Kei‐ichiro 
Published: February 2005

AbstractInterphylum crossing was examined between sea urchin eggs (Temnopleurus hardwicki) and oyster sperm (Crassostrea gigas). The eggs could receive the spermatozoa with or without cortical change. The fertilized eggs that elevated the fertilization envelope began their embryogenesis. Electron microscopy revealed that oyster spermatozoa underwent acrosome reaction on the sea urchin vitelline coat, and their acrosomal membrane fused with the egg plasma membrane after the appearance of an intricate membranous structure in the boundary between the acrosomal process and the egg cytoplasm. Oyster spermatozoa penetrated sometimes into sea urchin eggs without stimulating cortical granule discharge and consequently without fertilization envelope formation. The organelles derived from oyster spermatozoa seemed to be functionally inactive in the eggs whose cortex remained unchanged.
Stimulation of endogenous protein phosphorylation in oocytes of Sabellaria alveolata (polychaete annelid) at meiosis reinitiation induced by protease, fertilization, or ionophore A 23187
Authors: Peaucellier Gérard , Doree Marcel , Demaille Jacques G. 
Published: February 2005

AbstractIncorporation of [32P]‐phosphate into proteins was enhanced when Sabellaria oocytes were stimulated with specific protease to continue from prophase I block to metaphase I block. The rate of incorporation was increased 50 fold between onset of treatment and germinal vesicle breakdown (GVB). The same result was obtained when release from prophase block involved fertilization, or activation with ionophore A 23187. In all cases, meiosis was associated with phosphorylation of an 18,000 dalton protein, which is perhaps not labeled in prophase‐blocked oocytes. Phosphorylation of a 38,000–40,000 dalton doublet of membrane proteins, which are among the main phosphorylated proteins in intact oocytes, was also strongly enhanced in vitro in homogenates prepared from oocytes following release from prophase block.