bluuebunny/crossref_metadata_2025 huggingface dataset:
The feeding mechanism of the oyster. I. On the pallium and the branchial chambers of Ostrea virginica, O. Edulis and O. Angulata, with comparisons with other species of the genus
Authors: Nelson Thurlow C (Hristian)
Published: February 2005

Separation of the mantle from the visceral mass on the right side in deeply cupped species of oyster provides a shorter channel for egress of water from the right demibranchs. Correlated with this change is reduction in size of the right epibranchial chamber beneath the adductor together with backward displacement of the adductor itself. This water passage, designated the promyal chamber, develops during the first week after attachment of the oyster larva. The greatest displacement of the adductor and the largest promyal chamber occur in O. frons. The mantle border shows three reduplications of which the innermost, the pallial curtain, controls the amount and the place of entrance and egress of water. The importance of pallial curtains and promyal chamber to survival in turbid waters is discussed; oysters with the promyal chamber have invaded the river mouths, the flat oysters without this chamber have remained in the clear waters of high salinity near the sea. The bearing of these factors on the disappearance of fossil oysters is considered. It is proposed to relate to the genus Ostrea all flat, larviparous oysters which lack the promyal chamber and to raise the subgenus Gryphaea to generic rank to include all deeply cupped oviparous oysters with the promyal chamber. Anatomical and histological features of the pallium and branchial chambers are considered in detail.
Lifetimes of atomic Rydberg states by autocorrelation function
Authors: Jabri H , Eleuch H , Djerad T
Published: February 2005

We have derived the autocorrelation function for the
field emitted by a Rydberg atom in a micocavity weakly excited in
the strong coupling regime and in the non-resonant case. We
propose simple analytical expressions and make use of them to
determine the atomic frequency and the mean radiative lifetime of
the Rydberg atom. As compared to direct measurements this method
is promising.
S-band erbium-doped fiber ring laser using a fiber Bragg grating
Authors: Ahmad H , Saat N K , Harun S W
Published: February 2005

A short wavelength band erbium-doped fiber laser
(S-band EDFL) is demonstrated utilizing a fiber Bragg grating
(FBG) in unidirectional ring configuration. The amplification in
S-band is achieved using an erbium-doped fiber with depressed
cladding, which suppressed gains at longer wavelength. The laser
operates at 1500 nm, which coincides with the FBG wavelength. The
optimum EDFL operation is obtained by routing only 10% of the
laser output into the cavity. The laser has an output power of
7.8 dBm, more than 60 dB of peak to floor separation and 3 dB
bandwidth of less than 0.08 nm. This fiber laser provides an
inexpensive source for tunable output in the wavelength range from
1480 to 1520 nm.
On the solvability of a nonlinear boundary value problem arising in the theory of growing cell populations
Authors: Latrach K. , Taoudi M. A. , Zeghal A.
Published: February 2005

In this paper we establish some results regarding the existence of solution on L1 spaces to a nonlinear boundary value problem originally proposed by Lebowitz and Rubinow (J. Math. Biol. 1974; 1:17–36) to model an age‐structured proliferating cell population. Our approach, based on topological methods, uses essentially the specific properties of weakly compact sets on L1 spaces. Our results provide positive answers to the questions posed in Jeribi (Nonlinear Anal. Real World Appl. 2002; 3:85–105). Copyright © 2005 John Wiley & Sons, Ltd.
Effects of various enzymes on the ability of hamster egg plasma membranes to fuse with spermatozoa
Authors: Hirao Y. , Yanagimachi R.
Published: February 2005

To investigate which component of the plasma membrane of the hamster egg plays the central role in the sperm–egg fusion, the egg membrane was treated with a variety of proteolytic, carbohydrate‐hydrolyzing, lipid‐hydrolyzing, and other enzymes. The only enzyme that markedly effected the ability of the egg membrane to fuse with spermatozoa was phospholipase C. The lipid moieties of the egg plasma membrane (and possibly of the sperm membrane) must be of primary importance in sperm–egg fusion at fertilization.
Observations on the fine structure of vole spermatozoa with particular reference to cytoskeletal elements in the mature sperm head
Authors: Koehler James K.
Published: February 2005

Epididymal spermatozoa from two species of vole demonstrate cytoskeletal structures closely associated with the plasma membrane. Microtubule‐like elements (2O–24 nm in diameter) form a parallel sheath radiating from the posterior ring to the inferior acrosomal margin just beneath the plasma membrane. Fine filaments (5–8 nm in diameter) are associated with the cell surface, especially in the region of the concave curvature of the acrosomal hook. Both of these elements may aid in stabilizing these respective areas and it is suggested that microtubule‐like and filamentous structures may serve important cytoskeletal roles in the mature sperm head.
A simple method for the isolation of a large number of ova from pig ovaries
Authors: Oikawa Taneaki
Published: February 2005

A simple method for the collection of a large number of ova from pig ovaries is described. The method consists of disrupting the tissue in an ordinary meat grinder, then separating the oocytes by sieving the disrupted tissue through two pore sizes of stainless steel mesh.
Release of acrosomal enzymes following in vitro capacitation of ejaculated rabbit spermatozoa
Authors: Akruk S. R. , Farooqui A. A. , Williams William L. , Srivastava P. N.
Published: February 2005

Significant release of the acrosomal enzymes arylsulfatase, β‐N‐acetylhexosaminidase and hyaluronidase was observed following the treatment of ejaculated rabbit spermatozoa for 12 hours in 20% rabbit serum for inducing in vitro capacitation, and these sperm were capable of in vivo fertilization; however, the treatment of sperm for 15 minutes in high ionic strength (380 mOsm/kg) or low ionic strength medium (305 mOsm/kg) for in vitro capacitation did not result in any significant release of the above enzymes nor were the sperm capable of in vivo fertilization. Serum‐treated spermatozoa remained significantly motile following the 12 hour treatment, 51% underwent the acrosome reaction and were capable of fertilizing 66% of the ova in vivo. Identical serum treatment of lysosomes from rabbit liver resulted in a comparable release of the lysosomal enzymes. Serum treatment for in vitro capacitation resulted in vesiculation of the anterior margin of half the spermatozoa, but left their inner acrosomal membranes and equatorial segments intact. A biochemical relationship between the release of acrosomal enzymes and capacitation is suggested.
Cell surface changes in the proteins of rabbit spermatozoa during epididymal passage
Authors: Nicolson Garth L. , Brodginski Adele B. , Beattie Gillian , Yanagimachi Ryuzo
Published: February 2005

Differences in the exposure of spermatozoa surface components during epididymal passage have been examined using lactoperoxidase‐catalyzed 125I‐iodination or labeling with 125I‐diazodiiodosulfanilic acid. Labeled surface proteins obtained from caput and cauda epididymides were solubilized in detergent, separated by sodium dodecylsulfate polyacrylamide slab gel electrophoresis, and identified by radiography. Densitometer scans of autoradiograms revealed increased amounts or exposures of surface proteins of ∼35,000, ∼39,000, ∼50,000, and ∼78,000 molecular weight on the cauda epididymal spermatozoa.
Evidence that selenium in rat sperm is associated with a cysteine‐rich structural protein of the mitochondrial capsules
Authors: Calvin Harold I. , Cooper George W. , Wallace Edith
Published: February 2005

The keratinous capsules surrounding rat sperm mitochondria were isolated 24 days after intratesticular injections of [75Se] selenite or [35S] cysteine. Dodecyl sulfate‐polyacrylamide gel electrophoresis of purified, doubly labeled mitochondrial capsules revealed only a single 75Se‐labeled component, whose molecular weight was 17,000, in agreement with previously reported observations obtained with cruder sperm fractions. Most of the 35S label and the major zone of stained protein on the gels coincided with the position of 75Se, suggesting that selenium is associated with a cysteine‐rich structural protein. The level of selenium in rat sperm, 195 ± 3.2 ng/108 sperm (approximately 30 ppm), determined by hydride generation and atomic absorption spectrophotometry, is consistent with a structural function for this trace element in the sperm.
Effects on spermiogenesis in the mouse of a male sterile neurological mutation, Purkinje cell degeneration
Authors: Handel Mary Ann , Dawson Melissa
Published: February 2005

Purkinje cell degeneration (pcd) is a neurological mutation in the mouse that causes male sterility, but not female sterility. In order to assess the effects of this mutation on spermiogenesis, the structure of the testis and of epididymal spermatozoa was examined by transmission and scanning electron microscopy. In the mutant males, the sperm count was reduced, sperm were nonmotile, and 93% of the sperm were characterized by structural abnormalities of the head, the tail, or both. In the testes of mutant mice, Sertoli cell structure was normal, as were also the early stages of spermiogenesis. However, the elongating and maturing spermatids were characterized by abnormally shaped heads and tails with extraneous and ectopic outer dense fibers. These defects were common in the testes of the mutant mice and rare in the testes of the littermate control mice. It was concluded that the structural abnormalities of the pcd sperm occurred during spermiogenesis and were not due to degeneration of the sperm in the epididymis. These structural abnormalities are similar to those found in all other reported male sterile mutants of the mouse; therefore, although they are caused by the expression of the pcd gene, they are not unique to the expression of this gene.
Inhibition of the metabolism of ram spermatozoa by derivatives of α‐chlorohydrin
Authors: Brown‐Woodman P. D. C. , White I. G. , Ridley D. D.
Published: February 2005

The effects of the male antifertility agent, α‐chlorohydrin, six of its derivatives, and glycidol were studied on the metabolism of washed ram spermatozoa in vitro with fructose as substrate. The α‐chlorohydrin derivatives were the amino, the phosphorylated, and four glycol‐bridge (ketal) compounds. All compounds except glycidol, in a concentration between 0.1 and 100 mM, reduced the aerobic glycolsis and/or oxidation of fructose. However, there was not a high correlation between the ability of these compounds to inhibit the metabolism of ram spermatozoa in vitro and their antifertility activity when administered to male rats. Other factors are clearly involved in their antifertility activity, eg, the concentration of the compounds in the epididymis and their conversion of either more or less spermicidal compounds in the body.
Effects of various lipids on the acrosome reaction and fertilizing capacity of guinea pig spermatozoa with special reference to the possible involvement of lysophospholipids in the acrosome reaction
Authors: Fleming Alan D. , Yanagimachi Ryuzo
Published: February 2005

The effects of lipids on the survival, acrosome reaction, and fertilizing capacity of guinea pig spermatozoa were studied by incubating the spermatozoa in media containing various concentrations of the lipids. Lipids tested were: phosphatidyl‐choline (PC), ‐ethanolamine (PE), ‐inositol (PI), ‐serine (PS), sphingomyelin (S), cholesterol (C), lysophosphatidyl‐choline (LC), ‐ethanolamine (LE), ‐inositol (LI), ‐serine (LS), and glyceryl monooleate (M).

When spermatozoa were incubated in a regular medium (containing 2 mM Ca2+) with M, the majority underwent the acrosome reaction within 1 hour. None of the other lipids were as effective as M, and some were totally ineffective under the same conditions. However, when spermatozoa were preincubated in Ca2+‐free medium containing LC, LE, or LI, they gained the ability to undergo the acrosome reaction. One hour of preincubation in Ca2+‐free medium with LC, LE, or LI was enough to render the vast majority of spermatozoa capable of undergoing the acrosome reaction in response to Ca2+. The optimum concentrations for LC, LE, and LI were approximately 85 μg/ml, 210 μg/ml, and 140 μg/ml, respectively. Spermatozoa that had undergone the acrosome reaction by pretreatment with LC, LE, or LI remained actively motile and were capable of fertilizing eggs. LS was totally ineffective in rendering the spermatozoa capable of undergoing the acrosome reaction, and in fact it inhibited the acrosome reaction by itself and also inhibited the LC‐, LE‐, or LI‐mediated acrosome reaction. LS did not prevent acrosome‐reacted spermatozoa from penetrating the zona pellucida, but did prevent sperm‐egg fusion.

Based on these findings, it is suggested that lysophospholipids are intricately involved in the sperm acrosome reaction and perhaps in sperm‐egg fusion.
Fine structural abnormalities in the developing mouse embryo
Authors: Chakraborty Jyotsna
Published: February 2005

Initial changes in the fine morphology of apparently normal mouse zygotes and embryos were studied in serial sections of mouse oviducts that had been fixed in situ. These changes included extra sperm in the perivitelline space, nuclear budding, the presence of large nucleoli, perinuclear vesicles, the concentration of cytoplasmic organelles, and the extrusion of cytoplasmic ground substance. Initial changes in the nucleus and cytoplasm were undetectable when the zygotes and embryos were examined with the light microscope. It was concluded that serious abnormalities in zygotes and embryos, which may not be identified at the light microscope level, may be detected if they are examined in the electron microscope. Therefore, zygotes and embryos should be critically evaluated before being rated as normal.
The ultrastructural organization of the mature spermatozoon of Luidia clathrata (Say) (Echinodermata: Asteroidea)
Authors: Dehn Paula F. , Hinsch Gertrude W.
Published: February 2005

The sperm of Luidia clathrata are morphologically typical of asteroid sperm. The head is spherical and contains the nucleus and acrosomal complex. The nucleus has an anterior indentation in which rests the acrosomal complex. There is no evidence of a centriolar fossa along the posterior border of the nucleus. The acrosome is a cup‐shaped structure containing a less electron dense central region. The periacrosomal material is homogeneous in nature, and the subacrosomal specialization of the periacrosomal materials appear as bands of varying electron density. The middle piece is an annular band of mitochondria which surrounds the proximal and distal centrioles. The centrioles exhibit the typical nine triplet arrangement. Both the centrioles and the axoneme project to one side of the middle piece region. Associated with the distal centriole is an elaborate pericentriolar process.
Unilateral tunicamycin sensitivity of gametogenesis in dioecious isogamous chlamydomonas species
Authors: Wiese Lutz , Mayer Robert A.
Published: February 2005

Sex cell adhesion in isogamous chlamydomonads is caused by a complementarity between sex‐specific mating type substances, glycoproteins anchored in the flagella membrane of (+) and (\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop - \limits^. $\end{document}) gametes. The systems of mating type substances are species‐specific and condition, by their individuality, gametic incompatibility between species. The adhesion systems of several species share one common feature: the attainment of the agglutination capacity is sensitive to tunicamycin, but in one sex only. The effect is interpreted as due to the interference of tunicamycin with the synthesis of the mating type substances by blocking of their glycosylation in one but not in the other sex. It is postulated that the tunicamycin‐sensitive gametic adhesiveness depends, within the mating‐type‐specific glycoprotein, on an N‐glycosidically bound ligand of carbohydrate nature. A concept on the origin of sibling species by mutative modulations within the proper ligands of the glycoproteinaceous mating type substances is developed.
Fucosylation of glycoproteins in rat spermatocytes and spermatids
Authors: Grootegoed J. Anton , Krüger‐Sewnarain Bea C. , Jutte Nicolet H. P. M. , Rommerts Focko F. G. , van der Molen Henk J.
Published: February 2005

Glycoprotein synthesis in pachytene spermatocytes and round spermatids, isolated from rat testes, was studied by analysis of the incorporation of (3H)‐fucose. The isolated germ cells were capable of incorporating (3H)‐fucose into cell‐bound, acid‐precipitable components for an incubation period of at least 23 hours (at 32°C). In young spermatids, engaged in the formation of the acrosome, (3H)‐fucose was incorporated into more than 16 different glycoproteins within the molecular weight range of 20.000–100,000. A qualitatively similar set of glycoproteins was found to be labeled in spermatocytes. Radioautography showed that after 4 hr most of the incorporated radioactivity was present at one pole in the perinuclear zone of spermatocytes and spermatids, which could reflect incorporation of fucose in the Golgi apparatus. The newly fucosylated glycoproteins were associated with a particulate subcellular fraction (membrane fraction). Trypsin treatment of whole cells after 25 hours of incubation with (3H)‐fucose, however, did not cause significant lysis of tritiated glycoproteins.

From the results it was concluded that the majority of the newly fucosylated glycoproteins in spermatocytes and spermatids remained associated with an intracellular membrane system, presumably the Golgi apparatus and the vesicles that arise from this structure, to be deposited subsequently in proacrosomic granules and the acrosome. The results also suggest that initiation of the synthesis of spermatidal glycoproteins occurs during the prophase of meiosis in spermatocytes.
“Spontaneous” hardening of the zona pellucida of mouse oocytes during in vitro culture
Authors: de Felici Massimo , Siracusa Gregorio
Published: February 2005

Culture in vitro causes a slow, progressive hardening of the zona pellucida (ZP) of fully grown dictyate oocytes isolated from the mouse ovary. Hardening cannot be prevented by inhibitors of peroxidase or by a tyrosine analogue. Culture in anaerobic conditions is very effective in preventing ZP hardening. If the oocyte is cultured surrounded by its own follicle cells or in contact with cumuli oophori obtained from superovulated females, hardening is much reduced. The results suggest that the “spontaneous” hardening in cultured ovarian oocytes is not due to a cortical reaction, and that a diffusible factor is produced by follicle cells that protect the ZP from hardening.
Interaction of human sperm with zona‐free hamster eggs: A freeze‐fracture study
Authors: Koehler James K. , Decurtis Ivan , Stenchever Morton A. , Smith Dianne
Published: February 2005

An ultrastructural study has been carried out on the interaction of human sperm with zona‐free hamster oocytes. Scanning, thin‐section, and freeze‐fracture electron microscopy were used to examine sperm in the process of contacting and fusing with the egg surface. Microvilli from the oocyte attach to the sperm head at anterior and posterior loci, initial contact often being made with the inner acrosomal membrane. Freeze‐fracture study reveals that microvilli specifically contact particle‐rich regions of the sperm head surface, and fusion with the oolemma occurs in the equatorial region of the spermatozoon. Intramembranous particle aggregation was observed on the postacrosomal and neck regions of spermatozoa and resulted from glutaraldehyde fixation and glycerolation, since fast freezing of unfixed specimens did not show patching. Counts of intramembranous particles on sperm head plasma membranes showed a reversal of the usual P face/E face ratios for unfixed, fresh sperm, whereas capacitated populations retained the usual particle distributions on P and E faces, even in unfixed, fresh samples. It is suggested that a switching of binding properties of integral proteins may occur during capacitation, resulting in a higher stability of the P‐face association in unfixed cells.
Reproduction in mice: The fate of spermatozoa not involved in fertilization
Authors: Watson J. Gary , Carroll Joseph , Chaykin Sterling
Published: February 2005

Mechanisms were sought through which the control of preimplantation mouse embryo development by spermatozoa might be effected. A potential route for the transmission of sperm‐dependent stimuli to C3HeB/FeJ females was uncovered. It was found that within 24–48 hr after artificial insemination with spermatozoa, in which the DNA had been labeled with tritiated thymidine, a minimum of 9% of the radioactivity was transported across the uterine walls. It was deposited among the maternal tissues in a pattern that differed from the patterns of isotope distribution obtained when either free tritiated thymidine or Escherichia coli cells containing DNA labeled with tritiated thymidine were used instead of labeled sper‐matozoa. In sperm‐treated animals the ovaries, the adrenals, and a mesenteric lymph node exhibited strikingly large accumulations of radioactivity. The heart, spleen, and uterus manifested lesser accumulations of label, but were higher than liver, kidney, lung, brain, muscle, and intestine. The specific activity of the lymph node was found to decrease during the 12–72‐hr period following insemination. This result led to the hypothesis that the lymphatic system could serve as a route for the dissemination, to maternal tissues, of radioactivity originally associated with spermatozoa deposited in the uterus. Heat‐inactivated spermatozoa, which have the potential for facilitating the first cleavage of fertilized embryos, exhibited a distribution pattern indistinguishable from untreated spermatozoa. Sperm protein kinase was found to survive the heat inactivation of spermatozoa. This stability was interpreted as being compatible with the kinase functioning as an intermediary in the transmission of sperm‐dependent stimuli that control preimplantation embryo development in mice.
Acid release, cytoplasmic alkalinization, and chromosome condensation during sea urchin fertilization and amine‐lnduced parthenogenesis
Authors: Lois Augusto F. , Neill Dori J. , Carroll Edward J.
Published: February 2005

We have studied the relationship between acid release, cytoplasmic alkalinization, and the extent of chromosome condensation during parthenogenetic activation of sea urchin eggs. The relative rate of acid release in Strongylocentrotus purpuratus eggs was determined from pH measurements of egg suspensions. Acid release in inseminated eggs began after a lag of 0.4 min and the relative rate increased 108‐fold, declined, and release was essentially complete by 8‐min postinsemination. An average of 3.8 ± 0.23 × 10−12moles H+ cell− was released as determined by backtitration with NaOH. Acid release characteristics of eggs parthenogenetically activated with either NH4C1, methylamine ethylamine, n‐propylamine, n‐butylamine, or benzylamine were qualitatively similar. There was no detectable lag peroid and the increase in relative rate of acid release was directly proportional to the carbon number of the amine used, eg, from 8.3‐fold methylamine to 470‐fold with benzylamine. The total equivalents of acid released ranged from 0.50–8.2 × 10−12 moles H+·cell− in direct proportion to the concentration of amine used. The degree fo cytoplasmic alkalinization induced as a function of methylamine and benzylamine concentration was determined by pH measurements fo egg homogenates; egg cultures were also prepared for microscopic examination of chromosome condensation. None of the eggs had condensed chromosomes at 0.5‐mM methylamine whereas a cytoplasmic alkalinization of 0.6 pH units was observed. Increased methylamine levels up to 10mM resulted in chromiosome condensation in only 20% of the eggs. A similar result was found with benzylamine. We conclude that acid release and cytoplasmic alkalinization during chemical parthenogenesis are insufficient to mimic sperm induction of chromiosome condensation and suggest that an additional factor(s) is required for chromosome condensation by low concentration of amines.
Incorporation of L‐3H‐fucose in the rete and ovary of the fetal mouse
Authors: Jagiello Georgiana M. , Dennis James , Hiura Masamichi , Ducayen Mercedes B.
Published: February 2005

The concept of Byskov which hypothesizes a glycoprotein inducer of meiosis for the mammalian fetal ovary has been tested by examining the incorporation of the specific precursor 3H‐fucose into the rete ovarii of day 14 mouse ovaries. Semiquantitation of grains in autoradiographs has documented a concentration over the rete ovarii which exceeded that over the oogonia, ovarian fibroblasts, or surface epithelia. These data support the concept that the cytoplasm of mouse rete ovarii is capable of synthesizing a glycoprotein that may be the meiosis‐inducing substance.
Ultrastructural studies of spermatozoa in three bivalve species with notes on evolution of elongated sperm nucleus in primitive spermatozoa
Authors: Franzén Åke
Published: February 2005

Sperm ultrastructure and spermiogenesis of the three bivalve species Musculus discors, Nucula sulcata, and Dreissena polymorpha have been studied. During spermatid differentiation in Musculus discors and Nucula sulcata the nucleus attains an elongated rod‐like shape. The spermatozoon from Nucula sulcata was found to have a cup‐shaped acrosome and five mitochondria surrounding two centrioles in the middle piece. The spermatozoa from Musculus discors has a long complex acrosome. From the distal centriole striated processes extend and attach to the plasma membrane. The spermatozoon of the fresh water species Dreissena polymorpha agrees in all main features with those of other invertebrate groups with external fertilization. It is thus of the primitive type with barrel‐shaped nucleus and four to five mitochondria1 spheres in the middle piece. The acrosome is a prominant, complex structure at the apex of the mature spermatozoon.

A comparison of sperm ultrastructure among bivalves indicates that there is a certain correlation between the evolution of the elongated sperm nucleus and large, yolk‐rich eggs. In species with an elongated sperm nucleus the increased egg size has often led to a lecithotrophic or direct development. The elongated nucleus is a slight modification of the primitive type. There is a great variation in acrosome structure among bivalve spermatozoa, reflecting diverging functional demands at fertilization of the eggs.
Human spermatogenic cell marker proteins detected by two‐dimensional electrophoresis
Authors: Narayan Perinchery , Scott B. Keyes , Millette Clarke F. , DeWolf William C.
Published: February 2005

Highly homogeneous populations of human pachytene spetmatocytes and round spermatids have been obtained from normal adult testis using unit gravity (STA‐PUT) sedimentation. Contaminating Leydig cells have been removed by density centrifugation in discontinuous Percoll gradients to yield resultant germ cell purities of 90–95% for pachytene spermatocytes and 89–96% for round spermatids. The total cellular polypeptide composition of separated human germ cells has been analyzed by two‐dimensional polyacrylamide gel electrophoresis to compare 1) human and mouse pachytene spermatocytes (species specificity), 2) samples of human spermatocytes obtained from different individuals (allo specificity), and 3) pachytene spermatocytes and round spermatids from the same patients (stage specificity). Mouse and human germ cells have been found to exhibit extensive homology, but identified marker proteins limited to human spermatocytes include a group of polypeptides at p45/5.9 as well as a protein at p67/5.2. Proteins unique to mouse germ cells include component p65/5.5. Comparisons between different preparations of human pachytene spermatocytes have revealed about 90% electrophoretic homology, but some striking allotypic variations have been noted including the proteins at p45/5.9. Finally, presumptive stage‐specific spermatogenic cell markers have been identified including the p45/5.9 polypeptides that are present only in human spermatocytes. Although the physiological roles of particular marker proteins have not yet been determined, the present findings indicate that purified spermatogenic cell populations may be analyzed biochemically to identify constituents important in the regulation of sperm development in man.
Postovulatory aging of human ova: II. Spontaneous division of the first polar body
Authors: Ortiz M. E. , Lucero P. , Croxatto H. B.
Published: February 2005

Two oocytes recovered from the Fallopian tube at 24 and 50 h following the LH peak in plasma were examined by light microscopy and transmission electron microscopy. The possibility of fertilization was excluded by clinical and morphologic evidence. In the earliest specimen, the first polar body showed condensed nuclear chromatin, without nuclear envelope, and is interpreted as entering interphase. In the other specimen, the first polar body was undergoing division, which is interpreted as spontaneous second meiotic division.
Plasma membrane structure in spermatogenic cells of the swordtail (teleostei, Xiphophorus helleri)
Authors: Jonas‐Davies J. A. C. , Winfrey V. , Olson G. E.
Published: February 2005

The plasma membrane of spermatogenic cells of the teleost Xiphophorus helleri was examined ultrastructurally and cytochemically in order to characterize the temporal development of the membrane specializations characteristic of the mature spermatozoon. Mature sperm display a mosaic distribution of Concanavalin A and Ricinus comrnunis I binding sites; the anterior region of the head displays an intense binding that is not seen in other surface regions. This asymmetric binding is evident in early spermatids and the area of lectin binding appears associated with the plasma membrane overlying the nucleus. Transmission electron microscopy reveals that the plasma membrane over the anterior region of the head is characterized by an ordered glycocalyx and a tight adherence to the underlying nucleus. Additional membrane differentiations were revealed both in the midpiece region where a “submitochondrial net” is attached to the plasma membrane and at the base of the axoneme where the plasma membrane possesses a “collar‐like” arrangement of circumferential rings. The possible functions of these differentiations, as well as their correlation to differentiations seen in sperm of other animal groups, are discussed.
Spermatogenic cell differentiation in vitro
Authors: Risley Michael S.
Published: February 2005

Culture conditions that support the in vitro development of many spermatogenic stages from the frog Xenopus laevis are described. Spermatogenic cells were dissociated with collagenase and preelongation stages aseptically isolated by density gradient centrifugation in Metrizamide. The cells were then cultured in modified forms of defined nutrient oocyte medium (DNOM). The development of spermatogenic cells was affected significantly by changes in fetal calf serum concentration, cell density, energy sources, and NaCl concentration. Optimum in vitro spermatid development was obtained when spermatogenic cells were cultured at relatively high densities (3–7 × l07 cells/25 cm2) in DNOM modified to contain 10% heat‐inactivated, dialyzed fetal calf serum, 2 mM 1‐glutamine, 0.1 % glucose, 15 mM HEPES buffer (pH 7.4), and 38.3–48.3 mM NaCl. These culture conditions also supported the differentiation of preelongation spermatids and spermatocytes isolated by density‐gradient centrifugation in Metrizamide and subsequent unit gravity sedimentation in gradients of bovine serum albumin. Approximately 95 % of such isolated spermatids and spermatocytes continued differentiating in vitro for 14 days at in vivo rates. Phase‐contrast and electron microscopy of the cultured cells demonstrated that in vitro differentiation was morphologically normal between the leptotene and elongate spermatid stages. Autoradiographic studies of preleptotene development demonstrated that spermatogonia proliferated and preleptotene spermatocytes developed to zygotene in 12‐day cultures. The results suggest that many spermatogenic stages in Xenopus can develop independent of Sertoli cells, and demonstrate that spermatogenic cell cultures can now be used for in vitro studies of spermatogenesis.
Rabbit spermatozoa undergo an acrosome reaction in the presence of glycosaminoglycans
Authors: Lenz R. W. , Bellin M. E. , Ax R. L.
Published: February 2005

Rabbit‐ejaculated spermatozoa were incubated in a chemically defined medium containing comercially available glycosaminoglycans (GAGs) at concentrations ranging from 0.1 to 100 μg/ml. Sperm were stained and examined for the degree of acrosome reaction and viability after 9 h of incubation. There were significant dose and treatment effects of the induction of the acrosome reaction. Viability did not differ significantly betweendoses or treatment. Heparin enhanced the acrosome reaction between concentrations of 0.1 to 1.0 μg/ml, whereas higher levels depressed the percentage of sperm undergoing the acrosome reaction. Seminal plasma added to sperm cultures depressed the stimulatory effect of GAGs. Treatment of chondroitin‐4‐sulfate with chondro‐4‐sulfatase prohibited the stimulatory effect. It is concluded that GAGs, components of the female reproductive tract, may promote the acrosome reaction so that successful fertilization can occur.
Effect of exposure to high environmental pressure on spermatogenesis in mice
Authors: Dott H. M. , Doré Caroline J. , Foster G. C. A. , Halsey M. J. , Monk Susan , Setchell B. P. , Wardley‐Smith Bridget
Published: February 2005

This study was designed to investigate the mechanism of the subfertility produced when male mice are exposed to high pressure [Baden et al, 1982]. In the first series of experiments, male BALB/c mice were exposed to 50 ATA helium pressure intermittently throughout spermatogenesis (5 weeks). Control mice were exposed to 1 ATA air under identical conditions for an equivalent period. Immediately after exposure half the mice in each group were sacrificed, the remainder being sacrificed 14 days later. Testes were weighed and prepared for histological examination, and spermatozoa were examined for motility and abnormalities. More testes in the pressure group had disorganised seminiferous epithelia and weighed less than the control group; in addition the motility of sperm was also reduced immediately after pressurisation.

In the second series, male mice were exposed to 50 ATA pressure, or 1 ATA air intermittently for only 1 week to assess whether this exposure, for a period sufficient only to affect epididymal sperm, had any effect on functional fertility. The males were subsequently mated with untreated females; no difference was seen between the groups for pregnancy rate, preimplantation loss, or fetal survival.

These data support the idea that the changes in spermatogenesis causing subfertility in mice are fairly subtle, but are consistent with the premature release of spermatids from seminiferous epithelium. Epididymal sperm remained functionally unaffected by exposure to high pressure.
Nucleolar transformations in the human oocyte after completion of growth
Authors: Tesařík Jan , Trávník Pavel , Kopečný Václav , Kristek František
Published: February 2005

Nucleolar ultrastrure was studied in fully grown human oocytes obtained from multilaminar preantral follicles and from follicles at different stages of antrum formation. Selective staining for ribonucleoproteins and 3H‐uridine labeling were used in attempt to better understand the nature and functional significance of homogeneous dense nucleoli found in oocytes from large antral follicles.

There was an apparent increase in the radio of nucleonema to nucleolar interstices, accompanied by a gradual degranulation of the nucleolonema during early stages of antrum fromation. The process of nucleolar homogenization continued in oocytes from medium‐size antralfollicles, island of more tightly packed fibrils being hybothesized to represent persisting active transcription units. Entirely filamentous and homogeneous nucleoli were typical for oocytes from large antral follicles. They were demonstrated to ribonucleoprotein filaments embedded in pale‐ staining matrix. They were demonstrated to contain newly synthesized RNA after a 30‐min pulse with 3H‐uridine. The described nucleolar transformations are interpreted as acorrelate of nucleolar transition from a site of RNA synthesis into a site of RNA Storage during in human oocyte preovulatory development.
Monensin blocks the first meiotic cell division of the Xenopus oocyte: Effect at the nuclear membrane level
Authors: Marot J. , Tso J. , Huchon D. , Mulner O. , Ozon R.
Published: February 2005

The carboxylic ionophore monensin inhibits the meiotic maturation of the Xenopus oocyte. When oocytes are exposed to high concentrations of monensin (10 μM), both progesterone and MPF‐induced (maturation‐promoting factor‐induced) maturations are blocked. Lower doses of monensin (1–10 μM) do not inhibit the formation or amplification of MPF activity in the oocyte cytoplasm; however, breakdown of the nuclear envelope does not occur. These observations show that monensin, which is known to abolish intracellular proton gradients, interferes with the mechanism of the breakdown of the nuclear envelope induced by MPF.
Delayed fertilization of anuran amphibian (Xenopus) eggs leads to reduced numbers of primordial germ cells
Authors: Wakahara Masami , Neff Anton W. , Malacinski George M.
Published: February 2005

Several media were tested for the extent to which they promoted high fertilization efficiencies in ovulated, stripped Xenopus eggs. One medium was selected for maintaining eggs in a ‘delayed fertilization’ (DelF) condition. DelF eggs displayed several unusual characteristics, including shift of the center of gravity, prominent sperm entrance site, and occasional polyspermy.

The frequency of normal pattern formation varied according to the length of time eggs were maintained in the DelF condition. Various developmental abnormalities were observed during gastrulation, neurulation, and organogenesis. Most abnormalities appeared, however, to be related to morphogenesis of the endoderm.

Primordial germ cell (PGC) development was examined in DelF eggs which displayed normal external morphological features at the swimming tadpole stage. PGC counts were usually normal in short‐duration (eg, 5 hr) DelF eggs, but frequently substantially reduced or completely diminished in longer‐duration (eg, 25hr) tadpoles. Six spawnings were compared and shown to exhibit considerable variability in fertility, morphogenesis, and PGC development. Yolk platelet shifts and developmental parameters were examined in two additional spawnings.

The subcortical cytoplasm in which the germ plasm is normally localized appeared to be disrupted in longer duration DelF eggs. That observation may account for low PGC counts in DelF tadpoles.
Changes at the hamster oocyte surface from the germinal vesicle stage to ovulation
Authors: Ebensperger C. , Barros C.
Published: February 2005

Immature and ovulated hamster oocytes were studied with the scanning electron microscope. Immature oocytes at the germinal vesicle stage have their surface uniformly covered by microvilli. When meiosis has progressed to the first meiotic metaphase the overlying surface shows the differentiation of a circular area 19 μm in diameter with a low density of microvilli. Later, from this region the first polar body emerges, and the oocyte surface at the point from which it was extruded shows a cluster of cytoplasmic, conical projections. When the zona‐free oocytes are cultured at 37°C for 5 minutes these projections disappear and the oocyte surface at that point becomes smooth. However, when the oocytes remain in the oviduct for several hours after ovulation these projections remain unchanged. The in vitro interactions of capacitated hamster sperm with the immature oocyte was always seen at microvillus surfaces and never associated with the differentiated regions.
Inactivation of the (+) gamete agglutinin during the mating‐type reaction in chlamydomonas
Authors: Wiese Lutz , Hardcastle Alison , Stewart Mary
Published: February 2005

Sex cell contact in Chlamydomonas is due to complementary sex‐specific glycoproteins (mating‐type substances, MTSs). Their interaction causes an instantaneous but labile flagella agglutination between sexually different gametes. The dynamic nature of this contact permits partner exchange between agglutinated gametes and accounts for the transitoriness of the contact, flagella adhesion being terminated upon ensuing pairing. This paper describes molecular events that underlie the adhesion potential of differentiated (+) gametes. In the contact‐establishing interaction with its receptors on the (−) flagella, the agglutinin of differentiated (+) gametes is inactivated. Compensating for this inactivation, the adhesion potential of gametes in agglutination is sustained by continuous replenishment of the inactivated MTS by newly synthesized units. If this glycoprotein neosynthesis is blocked by tunicamycin (TUM), the adhesiveness of differentiated (+) gametes ceases. It is postulated that this complex interaction with incapacitation and neosynthesis forms the basis of the dynamic nature of the flagella contact and eventually accounts for its termination at pairing.
The pH dependence of motility and the acrosome reaction of guinea pig spermatozoa
Authors: Murphy Susan J. , Yanagimachi Ryuzo
Published: February 2005

The effect of pH on both motility and the acrosome reaction of guinea pig spermatozoa was examined by transferring fully capacitated spermatozoa from Ca2+ ‐free medium to Ca2+ ‐containing media with various pH values (8.2, 7.5, 7.0, 6.7, 6.4, and 6.1). When transferred to media of pH 7.5 or 8.2, the spermatozoa underwent their acrosome reactions to the maximum level within 15–20 min. Acrosome‐reacted spermatozoa were vigorously motile. The intensity of sperm motility and the incidence of the acrosome reaction declined with decreasing pH values. At pH 6.1, the motility of all the spermatozoa quickly became very weak. No acrosome reactions occurred at this low pH. The inhibition of motility and the acrosome reaction at pH 6.1 was reversed by transferring the spermatozoa back to the alkaline medium unless they were exposed to this low pH for longer than 3 hr. The inhibition of the acrosome reaction at low pH values (other than 6.1) was counteracted to some extent by increased concentrations of Ca2+ (4–10 mM). Possible mechanisms by which low pH reversibly inhibits sperm motility and the acrosome reaction are discussed.
Different environmental stresses can activate the expression of a heat shock gene in rabbit blastocysts
Authors: Heikkila John J. , Schultz Gilbert A.
Published: February 2005

We have utilized the rabbit 6‐day blastocyst as a model system in which to examine the effect of environmental stress on embryonic gene expression. Elevation of the incubation temperature from 37 to 43 °C, exposure to 50 μM sodium arsenite or mechanical injury (resulting in the structural collapse of the 6–day rabbit blastocyst) was found to depress total protein synthesis as well as enhance the synthesis of a 70,000‐dalton stress‐induced protein. The molecular mass of this stress protein is similar to a heat shock protein (HSP) found in other eukaryotic systems. A recombinant DNA probe consisting of the 5′ end of a mouse gene for a 70,000‐dalton HSP hybridized to RNA isolated from heat shocked, sodium arsenite‐treated, and mechanically injured blastocysts but not to RNA isolated from control embryos. These results as well as in vitro translation data suggest that the expression of the 70 K HSP is controlled at the transcriptional level. The levels of actin mRNA, as detected by means of a recombinant DNA probe encoding a Drosophila actin gene, did not undergo a major alteration following these different stresses. The relevance of these observations to embryonic cellular homeostatis is discussed.
Lysosomal hydrolases in reproductive organs during estrous cycle of the hamster
Authors: Rahi Hamid , Srivastava Prakash N.
Published: February 2005

Changes in the total protein content and the activities of lysosomal hydrolases (arylsulfatase, acid phosphatases, β‐glucuronidase, β‐N‐acetylhexosaminidase, α‐L‐fucosidase, and β‐galactosidase) of the hamster genital tract during the 4 days of estrous cycle and in hormonally superovulated hamsters were measured. Levels of lysosomal hydrolases in uteri and uterine fluid changed significantly during the cycle. Similar changes were observed in uterine wet weight and uterine proteins. The pattern of enzyme activities in both the ovary and the oviduct were different from those in uteri. In the ovary, most enzyme activities and the total protein concentration remained elevated after ovulation. Protein concentration and enzyme activities were significantly higher in the ovary, oviduct, and uteri of superovulated hamsters as compared to controls.
Developmental capacity of rat embryos produced by in vivo or in vitro fertilization
Authors: Shalgi Ruth
Published: February 2005

This work compares the ability of rat zygotes fertilized in vitro or in vivo to develop into viable embryos. All oocytes were from adult cyclic females. After the first cleavage, the zygotes were transferred to oviducts of pseudopregnant recipients. Their fate was examined on day 13 at laparotomy and again on day 20. Ninety‐five of 146 in vivo fertilized zygotes developed into normal sized 13‐day fetuses and 72 (55%) to apparently normal near‐term fetuses. Forty‐six of 135 in vitro fertilized zygotes developed up to day 13, and 30 (24%) developed to term. It appears that the probability that in vitro fertilized rat zygotes will develop into viable embryos is about half the chance of in vivo fertilized zygotes. Since the two types of zygotes were morphologically identical, the morphological appearance of the two‐cell stage is not an adequate criterion for judging developmental potential.
Effect of anti‐sperm antibody on the in vitro development of rat embryos
Authors: Koyama Koji , Hasegawa Akiko , Isojima Shinzo
Published: February 2005

Since we previously proved that the fertilized rat eggs in early developmental stage have antigen(s) cross‐reacting to spermatozoa, the effect of antibody to spermatozoa on the cleavage of fertilized rat eggs was examined in vitro. Fertilized eggs from Fisher rats in the morula stage were cultured in vitro for 15 to 39 hr in the medium containing antibody to rat spermatozoa and rabit complement, and the developmental rates of morulae to blastocysts were compared with those cultured in the presence of either antibody or the complement alone. When rat morulae were cultured in the medium containing rabbit complement and IgG from rabbit antiserum to rat spermatozoa (heteroantibody) or from rat antiserum to rat spermatozoa (isoantibody), the development of moralae to blastocysts was markedly suppressed, whereas those cultured in the medum containing rabbit complement and IgG from the control rabbit serum or rabbit antibody IgG to rat spermatozoa alone without complement normally developed to the blastocysts. These results indicate that the antibody to spermatozoa in presence of complement can impair the in vitro development of fertilized rat eggs.