bluuebunny/crossref_metadata_2025 huggingface dataset:
The continuity of the germ cells in the urodele, Plethodon cinereus (Green)
Authors: Burger J. Wendell
Published: February 2005

Plethodon cinereus is favorable for a study of the history of the germ line. The germ cells are large, while the gonads are small and show an almost diagrammatic structure. Germ cell degeneration is not extensive during ontogeny. As long as all the germ cells contain yolk during development, these cells are derived solely from germ cells. In Plethodon, yolk lasts in all germ celis through sex differentiation. A comparison of the number of mitoses necessary for the primordial germ cells to produce the numbers of germ cells in gonads where every germ cell contains yolk, with the mitoses necessary for the primordial cells to produce the adult complements of germ cells, shows that at least 72% of the increase of germ cells can be followed by yolk. A cytological study from the embryo through the adult sexual cycle gave no evidence that somiatic cells ever transform into germ cells. Mitoses are abundant in the testes of salamanders starved 4 months. This fact together with a statistical study on the adult male sexual cycle indicates that the germ cells present in the testis do not need to be augmented by transformed somatic cells. It is concluded that in Plethodon germ cells alone give rise to germ cells, and that the germ line is continuous.
The effect of ultracentrifuging on Paramecium, with special reference to recovery and macronuclear reorganization
Authors: King R. L. , Beams H. W.
Published: February 2005

Paramecium caudatum becomes much elongated upon centrifuging at 21,000 times gravity. The chromatin is sometimes forced from the achromatic matrix of the macronucleus. The materials in the cell are redistributed according to their relative specific gravities as follows: At the centrifugal end of the cell, crystals, layer of fluid, micronucleus and macronuclear chromatin, food vacuoles and neutral red inclusions, achromatic matrix of the macronucleus, endoplasm with large clear alveoli, and fat, at the centripetal end of the cell. The contracting vacuole is displaced sometimes but not the feeding canals or pore. In some cases the crystals, micronucleus and macronuclear chromatin may be extruded from the cell. Animals which survive centrifuging regain their usual shape and the disturbed materials return to their usual distribution rapidly. Sometimes the crystals remain in large compact masses and are so passed to the daughter cells upon fission. The two components of the macronucleus do not fuse the macronuclear chromatin regenerates an achromatic matrix, and division is somewhat delayed. The old macronuclear matrix persists over a long time and sometimes interferes with division. Animals which have no micronucleus may survive and divide, but no amicronucleate races have been established. Apparently macronuclear chromatin is necessary for the survival and division of P. caudatum; in the absence of the macronuclear chromatin no replacement occurs from the micronucleus. The membrane of the contracting vacuole is temporary.
The dimensions of the renal tubules of Necturus maculosus
Authors: Kempton Rudolf Theodore
Published: February 2005

The method of micro‐injection was used in the study of a large number of tubules. The limits of the several parts of the tubule were determined with a high degree of accuracy without sectioning; the error of the measurements was small. Of 137 tubules studied the measurements of forty‐nine comprised the entire length from renal corpuscle to collecting duct or ureter.

The proximal tubule was found to be about twice as long as the distal. While the longest proximal tubule was nearly six times the length of the shortest, the great majority of tubules fell within a much shorter range. There was little or no correlation between proximal tubule length and weight of the animal.

The proximal tubule is larger in diameter than the distal tubule. Calculations indicate that the area of exposed cell surface in the proximal tubule is nearly four times as great as in the distal; however, compared to tubule volume, a relatively greater cell surface is exposed in the distal tubule.
Studies on the amphibian digestive system II. Comparative histology of the pancreas, following early larval development, in certain species of anura
Authors: Janes R. G.
Published: February 2005

Anatomically, the structure of the pancreas in four species of anura studied, is very similar during various stages of development. The gland is greatly reduced in size during both artificially induced and natural metamorphosis. When metamorphosis is artificially induced, the regression of the pancreas occurs somewhat earlier and is a little more rapid than in the case of natural metamorphosis, but the condition exhibited at the end of the phenomenon is similar in each case. Correlated with the anatomical regression during metamorphosis, many of the acinous cells, small collecting ducts and sinusoidal capillaries, undergo degeneration. This histolysis occurs somewhat earlier in animals that undergo artificially induced metamorphosis, but regeneration occurs about the same time in both metamorphic types. Most of the degenerated elements are autolyzed in situ; some are sloughed into sinusoidal capillaries; while a small number are eliminated through pancreatic ducts. It is doubtful whether these elements are ingested by phagocytes. The pancreas, in certain cases during later stages of metamorphosis, appears to take on a temporary hematopoietic function leading to the differentiation of red blood cells. Zymogen granules, lipoid granules, and X‐granules are demonstrated in the anuran pancreas. X‐granules, found in the larvae, are indeterminate in nature and are quite probably remnants of vitelline material found in the early embryo.
A study of the nucleoli of certain insects and the crayfish
Authors: Johnson Mychyle W.
Published: February 2005

Nucleoli in the germ cells of certain Orthoptera, Hemiptera and the crayfish have been studied. In Ceuthophilus (camel cricket) these bodies are found to be definitely connected with chromatin threads and are believed to be products of chromatin.

The large structure in the ova of Nemobius (cricket) is interpreted as a nucleolus because of its very irregular behavior and apparent complete disappearance.

It is found that some of the nucleoli of Gelastocoris (toad bug) arise within the chromatin threads.

Observations on Cambarus (crayfish) fail to show nucleolar extrusion, a phenomenon which has formerly been reported for this form.

The unique behavior and fate of the nucleolar material in Pselliopus (true bug) is described. In this species the nucleolar material is added to and becomes part of the general oxychromatin network of the nucleus.

This study fully supports the opinion that nucleoli have a chromatin origin.
The segmental excretory glands of Artemia salina linn., var. principalis simon. (the brine shrimp)
Authors: Warren Herbert Stetson
Published: February 2005

Artemia salina, a very widely distributed species in North America, Europe and Asia, breeds freely and rapidly under laboratory conditions, living in all salinities from fresh water to almost saturated brine. Its soft exoskeleton permits of easy sectioning.

The morphology and embryology of the segmentally arranged excretory glands—the antennal, mandibular and maxillary glands, are described. The antennal gland, consisting of extracellular end sac and intracellular excretory duct, is located in the second antenna and opens to the exterior on the lateroposterior face of the protopodite. It attains its maximum development by the sixth instar, degenerating by the tenth. The vestigial mandibular gland consists only of an end sac surrounding a schizocoele, and a rudimentary duct. The large maxillary gland in the adult consists of an end sac, an excretory duct of three circular coils, and a terminal duct opening to the exterior. The maxillary gland develops from a mass of mesenchyme cells in the maxillary segment of the nauplius, becoming fully differentiated by the sixth instar.

The vestigial second maxilla has two bristles. It serves only as a terminus for the maxillary gland. A pair of small ganglia are accepted as internal evidence for the presence of a maxillular segment.

The presence of three pair of schizocoeles in three consecutive segments is interpreted as evidence of homology with the Annelid coelome, with the possibility of further homologizing the excretory ducts with the segmental nephridia.
A cytological study of the ovaries of the bats Myotis lucifugus lucifugus and Myotis grisescens
Authors: Guthrie Mary J. , Jeffers Katharine R.
Published: February 2005

Ovaries of bats, Myotis lucifugus lucifugus and M. grisescens, have been studied in all phases, except gestation, of the annual reproductive cycle. Oocytes arise in the germinal epithelium and grow with an orderly differentiation of the storage products of metabolism—chondriosomes, fat drops, and yolk vesicles. The evidence indicates that the zona pellucida is derived from the oocyte. Squamous cells of the primary follicle become cuboidal and then columnar as follicular growth begins (unilaminar secondary stage). The secondary follicle becomes multilaminar and in a very few cases gives rise to a tertiary follicle by antrum formation. Most growing follicles undergo retrogression by one of two methods. Degeneration of type I is common in multilaminar follicles and begins in the granulosa which is almost completely obliterated before the oocyte is affected. Spindles occur in some of these oocytes and fragmentation is common; phagocytes eliminate the contents of the zona. In type II, which is rare and has been found only in unilaminar secondary follicles, the oocyte degenerates, leaving an uninjured granulosa. Medullary cords are common embryonic vestiges in these ovaries; epithelial nodules are less frequent. Interstitial cells are very numerous in newborn bats, arise throughout life from the hypertrophied thecae internae of retrogressing follicles of type I, are phagocytized and, also, undergo hyaline degeneration, are hypertrophied in late pregnancy, and continue so during lactation.
The chromosomes in the maturation of the germ cells of two species of triclad Turbellarians
Authors: Pennypacker Miriam I.
Published: February 2005

The maturation of the germ cells of the two hermaphroditic species, Curtisia foremanii (Girard) and Bdelloura candida (Girard) has supplied the material for this chromosome study.

Both species of flatworms are believed by the author to possess a diploid number of twelve chromosomes and a haploid number of six, although Curtisia foremanii has previously been reported as having a smaller and variable number of chromosomes.

A tendency of the chromatids comprising individual chromosomes to separate from one another at certain times was noted in both species. This action results in giving the appearance of a larger number of chromosomes than the germ cells actually possess. A further source of apparent increase in chromosome number in the Curtisia oocytes, after treatment with the usual Allen's B3 and B15 and Heidenhain's iron haematoxylin, is the presence of some deeply staining, non‐chromatin material.

No significant differences in number, form and behavior of chromosomes of male and female complexes were noted, with the possible exception of the tendency of the chromatids to separate from one another, to be greater in the female than in male germ cells.
Gynandromorph spiders
Authors: Exline Harriet
Published: February 2005

Four cases of gynandry in American spiders present the following morphologic deviations: The specimen belonging to Neoantistea agilis (Keyserling) externally is a bilateral gynandromorph with distortion of the single male palp, with half of the epigynum nearly normal; internally both testes and ovaries are present. The Drassodes neglectus (Keyserling) is not a completely developed bilateral gynandromorph. One side has a normal male palp, a larger chelicera and longer legs than the other, the epigynum is complete and normal; internally only degenerate ovaries are present. The Linyphiid, near Bathyphantes, is three‐quarters female, the only male organ being an imperfectly developed male palp. Ovaries are well developed but immature, whereas the epigynum is complete. In the Pardosa sternalis (Thorell) the anterior part of the body is male, as indicated by the swollen palps and the length of the legs; the epigynum is completely developed, but internal reproductive organs are missing except for a very much aborted ovary. The bisexuality in all cases has caused degeneration or abnormalities in the reproductive structures.

Included is a tabulation of all recorded instances of gynandry in spiders, arranged according to the type of abnormality. The term ‘leg‐index’ is introduced to express ratio between length of the leg and length of cephalothorax.
Morphogenesis of the cranial muscles of Amblystoma punctatum
Authors: Piatt Jean
Published: February 2005

The development of the cranial musculature of Amblystoma punctatum is described in detail, for both larva and adult. In addition, a brief account of the innervation of each muscle is given. The study of normal development is supplemented by extirpation experiments performed on embryos in early stages of development. These extirpations include the mesodermal head segments, mesoderm of mandibular, hyoid, second branchial, third branchial arches, and somites 1, 2 and 3. The eye muscles are found to develop from the mesodermal head segments in precisely the same manner as in other classes of vertebrates; head segmentation of Amphibia, though less accentuated, is shown to be homologous with that of other classes. The remaining extirpation experiments corroborate, in general, the finding from normal development studies. An attempt is made to summarize in tabular form the prospective fate of the prechordal plate and parachordal mesoderm, the two earliest divisions of the head mesoderm, with regard to their complete muscle derivatives.
Winning business: business development issues and priorities
Authors: Coulson‐Thomas Colin
Published: February 2005

Training and development activities are largely overlooking the attitudes, knowledge and skills required for relationship and account management and winning business in competitive bid situations.

There is considerable scope for using E‐business to develop new markets and change how business is done and for packaging and exploiting knowledge and understanding to generate additional income.

Many organizations devote too little emphasis to defining and communicating their corporate strengths and core competencies.

More proactive and differentiated approaches to business development are required. Greater selectivity and automating the more routine aspects of proposal preparation can release the resources needed to improve and tailor individual responses.

Prioritization, focus and learning from experience are vital. Proposals should be structured around the main requirements of the prospective customer and the key influencing and deciding factors that have been identified.

Copyright © 2001 John Wiley & Sons, Ltd.
Acceleration of onset of oocyte maturation in vitro by luteinizing hormone
Authors: Kaplan R. , Dekel N. , Kraicer P. F.
Published: February 2005

The purpose of this study was to analyze the effect of luteinizing hormone (LH) on the earliest stage of oocyte maturation ‐ the stage of breakdown of the dictyate nucleus. Oocytes were isolated from the preovulatory follicles of adult, cyclic rats. They were incubated in culture medium with or without 10 μg/ml LH. The cultures were observed continuously for up to 3 hours. Analysis of the rate of disappearance of the germinal vesicle nucleolus revealed that LH accelerated the breakdown process. The median times of disappearance were 91.3 minutes without LH and 62.3 minutes with LH. This is in accord with earlier reports on enhancement of fertilizability of oocytes matured in vitro with LH. Thus, although oocytes mature spontaneously in culture, the maturation remains LH sensitive.
Capacitation, acrosome reaction, and egg penetration by canine spermatozoa in a simple defined medium
Authors: Mahi Cherrie Ann , Yanagimachi Ryuzo
Published: February 2005

A 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

In 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

The 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

Ejaculated 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

In 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

The 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

During 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

Mouse 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

Ejaculated 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

Ejaculated 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

We 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

Glycogen 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

The 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

A 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

Ovaries 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

This 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

Oocytes 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

Labeling 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

The 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

Nuclear 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

The 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

Yolk 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.
Properties of the first and second factors released after hamster sperm make contact with the zona pellucida prior to fertilization in vitro
Authors: Hartmann John F. , Hutchison Cameron F.
Published: February 2005

An investigation was made as to the nature of two of the factors, termed S1, released within the first 30 minutes after contact is made between capacitated hamster sperm and the zona pellucida in vitro. Previous studies showed that these S1 factors were detected two and 20 to 25 minutes after the gametes were combined and that, based on filtration studies, the former possessed a molecular weight of less than 5,000 daltons. The present results show that the quantity of the 20–25‐minute S1 factor released into the supernatant increased linearly as a function of the sperm concentration. This factor passed unimpeded through a filter with a 5,000 molecular weight cutoff but only 42% of the activity traversed a filter with a cutoff of 2,000 daltons. The two‐minute S1 factor, in the virtual total absence of cells, was stable for 10 to 15 minutes, but lost significant activity upon longer incubation. Under the same conditions, the 20–25‐minute factor lost approximately 25% of its activity within 15 minutes, but remained stable at this level for at least 45 minutes of incubation. Both S1 factors were not affected by a mixture of glycosidases, but were inactivated by subtilisin, trypsin, and leucine aminopeptidase which was contaminated with endopeptidases. The activity of the two‐minute S1 factor appeared more susceptible to the action of the proteases than that of the 20–25‐minute S1 factor. In contrast to previous results obtained with the two‐minute S1 factor, the release of the 20–25‐minute S1 factor was not inhibited by the inclusion of soybean trypsin inhibitor a t concentrations which are known to inhibit penetration of the zona by the sperm. The results suggest that the two‐ and 20–25‐minute S1 factors are peptides which are not identical.
Inhibition of acrosin by oviductal secretory immunoglobulin A
Authors: Go K. , Mastroianni L. , Stambaugh R.
Published: February 2005

A major inhibitor of acrosin in rhesus monkey and rabbit oviduct fluid, isolated by isoelectrofocusing in sucrose gradients, displayed a broad peak in the acidic region of the column and was demonstrated to contain secretory IgA specific for acrosin. Its identity was established by immunodiffusion, by the removal of acrosin inhibition with antisera to IgA (α‐chain), and by its correct molecular weight during ultracentrifugation. Purified human serum IgA also inhibited rabbit, rhesus monkey, and human acrosins, but neither purified human IgG nor IgM had any inhibitory effect on these acrosins. Neither oviduct fluid secretory IgA nor purified human serum IgA inhibited the activity of bovine pancreatic trypsin. The high specificity of secretory IgA for acrosin and its presence in every rabbit and rhesus monkey oviduct fluid specimen examined suggests a possible regulatory role for this antibody in reproduction.
Factors which may affect removal of protamine from sperm DNA during fertilization in the rabbit
Authors: Wiesel Saul , Schultz Gilbert A.
Published: February 2005

In order to derive information about possible mechanisms by which the sperm head is converted into the male pronucleus during fertilization in the rabbit, unfertilized egg homogenate was assayed for two enzyme activities. Protamine was extracted from rabbit sperm, purified, and labelled with [14C] in an in vitro reaction and used as a probe to assay for a protein kinase which could transfer [32P]PO4 from [γ‐32P]ATP onto the substrate. A kinase with a pH optimum of approximately 8.0 to 8.5 is described. Assays for the enzyme glutathione reductase were performed using homogenates from eggs or embryos at three early stages of development. Results suggest that oocytes can oxidize 2.58 × 10−6 μmol NADPH per minute per oocyte, unfertilized eggs 5.16 × 10−7 μmol NADPH per minute per ovum, and 20‐ to 24‐hour postcoitus fertilized eggs 2.30 × 10−6 μmol NADPH per minute per ovum. The relevance of these observations to male pronuclear formation is discussed.
The effects of taurine and hypotaurine on in vitro fertilization in the golden hamster
Authors: Leibfried M. Lorraine , Bavister Barry D.
Published: February 2005

Taurine and hypotaurine were examined for their efficacy in replacing sperm motility factor (SMF), prepared from bovine adrenal cortex, for in vitro fertilization in the golden hamster. Combinations of these amino acids at concentrations of 0.001, 0.01, 0.1, and 1 mM together with 16 μM isoproterenol (a catecholamine β‐agonist) were added to the sperm incubations. After three hours of sperm preincubation, oviductal eggs were added to the sperm suspensions and examined for penetration and stage of fertilization after three or five hours of culture. At 0.001 mM, neither taurine or hypotaurine was capable of maintaining motility of hamster sperm for four to 4½ hours or of inducing fertilization. With all other concentrations, both amino acids were found to maintain motility of sperm as well as SMF. Hypotaurine stimulated motility to a greater extent than taurine and both required isoproterenol for the greatest motility. A low proportion of cumulus‐free ova were fertilized when sperm were preincubated with either amino acid alone over the range of 0.01 to 1 mM; however, over 80% fertilization was consistently obtained when isoproterenol was also present during sperm incubation. Proportions of ova fertilized with taurine or hypotaurine present during sperm preincubation were comparable to those achieved with SMF. The possibility that taurine or hypotaurine is the sperm motility factor is discussed.

After three hours of sperm/egg incubation, a lag in the early events of fertilization was observed in experimental groups treated with one of the amino acids (0.01 mM) alone compared with groups treated with isoproterenol present. However, if sperm/egg incubation was extended from three to five hours, no increase in number of eggs penetrated was found. Therefore, the delay observed at three hours was considered a function of fewer numbers of capacitated sperm present in the absence of isoproterenol rather than of the need for an extended capacitation time.
The spermatogenesis of crustaceans. VII. Review of spermatozoon of the crayfish Astacus astacus (Malacostraca, Decapoda, Macrura, Reptantia)
Authors: López‐Camps J. , Bargalló R. , Bozzo M. G. , Durfort M. , Fontarnau R.
Published: February 2005

The star‐like spermatozoon of Astacus astacus consists of a spheroidal central body around which various prolongations of same, denominated spines, are arranged. In the interior of the gamete the following parts may be distinguished: (1) The acrosomic region, formed by a complex vesicle, or thick‐walled, helmetshaped body, whose opening is orientated towards the nuclear region. In the interior of the vesicle different structures can be appreciated. (2) The nuclear region, which is formed by a large cupuliform nucleus limited by a double membrane. In the nucleoplasm numerous bundles of microtubules, mixed with noncondensated chromatin fibers, are found. (3) The laminar region, present in other Decapoda, is practically nonexistent. Within the spines of these spermatozoa, only microtubules can be observed. The morphology of this crayfish is similar to that presented by Brachiura, another group of Reptantia.
Fertilization in the sea urchin arbacia punctulata inhibited by fluorescein dyes: Evidence for a plasma membrane mechanism
Authors: Finkel Toren , Levitan Herbert , Carroll Edward J.
Published: February 2005

Fertilization and ionophore activation of the sea urchin Arbacia punctulata were inhibited in the presence of six analogs of the dye fluorescein. The concentration of any one dye needed for blockage of sperm or Ca‐ionophoremediated activation in 50% of the eggs (I50) was a function of the dye's lipid solubility. Substantially higher concentrations of each dye were required to block activation by Ca‐ionophore (A23187) than were needed to inhibit sperm activation. A detailed study of the action of Erythrosin B (tetraiodofluorescein) showed that its effects were readily reversible. The I50 concentration of Erythrosin B increased as temperature increased from 10 to 25°C. The kinetics of blockage indicated that Erythrosin B blocked some early step in the program of fertilization. The results suggest that these anionic dyes may inhibit fertilization by preventing successful sperm‐egg fusion.
Effect of anti‐pig zona pellucida serum on fertilization in several mammals
Authors: Tsunoda Y. , Soma T. , Jinbu M. , Tachiura K. , Sugie T.
Published: February 2005

The effect of goat antiserum against isolated pig zonae pellucidae on fertilization in vivo was examined in the pig, cow, sheep, rabbit, rat, and mouse. As shown by indirect immunofluorescence, anti‐pig zona serum reacted strongly with the zonae of pig, cow, sheep, and rabbit, but the reaction with the zonae of mouse and rat was weak. Passive immunization with anti‐pig zona serum significantly, or completely, inhibited fertilization in all species. However, inhibition of fertilization was more pronounced in the pig, cow, sheep, rabbit, and mouse than in the rat. Inhibition of fertilization in the rabbit was also observed after passive immunization with antiserum absorbed with rabbit liver and kidney. All of the zonae recovered from the pig, cow, sheep, rat, and mouse after passive immunization with anti‐pig zona serum exhibited strong fluorescence, regardless of the incidence of fertilization. It was concluded that the pig and other mammalian zonae pellucidae tested have tissue‐specific antigens.