bluuebunny/crossref_metadata_2025 huggingface dataset:
The histology of the paraphysis of Amblystoma
Authors: Roofe Paul Gibbons
Published: February 2005

The paraphysis of adult Amblystoma is made up of low columnar ependymal epithelit m which forms the paraphyseal tubules which end blindly and which communicate with one another by a common mouth with the third ventricle. Between the paraphyseal tubules venous sinusoids anastomose freely with one another forming a complicated rete. The sinusoids are made up entirely of endothelium. The blood supply to the paraphysis is entirely venous.

Mitochondria were found in great abundance in the paraphysis of one female just previous to laying. Other specimens showed very few present. No conclusions can be drawn from these few observations as to the relationship between physiological activity and cellular structures.

The Golgi apparatus was observed definitely localized between the nucleus and the ventricular end of the cell.

Many large crystalloids were also observed to be localized between the nucleus and the ventricular end of the cell.

Intercellular spaces are readily observed in sections stained with Mallory's connective tissue stain. Nassonow's osmic acid technique for the Golgi apparatus and Benda's crystal violet and alizarin stain clearly bring out the intercellular canals. Acid fuchsin stained particles within the intercellular spaces are more abundant toward the sinusoids than the cavities of the paraphyseal tubules. The intercellular canals have not been seen to communicate with either the sinusoids or the cavities of the paraphyseal tubules in any of the preparations observed.
Nuclear reorganization processes in Paramecium aurelia, with descriptions of autogamy and ‘hemixis’
Authors: Diller William F.
Published: February 2005

In a study of the nuclear behavior of Paramecium aurelia, a process of self‐fertilization, autogamy, has been discovered and traced through its essential steps. Autogamy is the counterpart, in a single animal, of conjugation. In autogamy, three micronuclear divisions lead to the formation of the gametic nuclei. These divisions are considered to be maturation divisions. The first division is characterized by a great increase in the size of the two vegetative micronuclei and the occurrence of long thread‐like crescents. The second division results in the formation of eight nuclei, variable numbers of which continue to divide giving rise to the potential gametic nuclei. Two of the latter unite to form a synkaryon. The old macronucleus disintegrates. The fusion nucleus divides twice: two of the daughter nuclei become macronuclear anlagen, while the other two remain micronuclei. The macronuclear anlagen are distributed to two daughter cells at the time of the first cell division, when the micronuclei divide.

The macronuclear changes in hemixis can be classified into three main types: (1) the extrusion of a relatively small number of spherical chromatin fragments; (2) the splitting of the macronucleus into two (generally) large independent portions—accompanied, or not, by the extrusion of smaller spherical bodies; (3) the complete disorganization by fragmentation of the macronucleus.
Histological changes accompanying the growth of the mid‐intestine of Japanese beetle larvae (Popillia japonica Newman)
Authors: Ludwig Daniel , Abercrombie W. Fulton
Published: February 2005

A study was made of the changes in the mid‐intestinal epithelium accompanying the growth of first and scond instar Japanese beetle larvae. The columnar cells were counted and measured in the region limited by the second and third rings of gastric caeca.

During the first 4 days of each instar (at 25°C.), there is no increase in the number of columnar cells, growth being due entirely to an increase in the size of cells already present. The number of columnar cells begins to increase about the fifth day of each instar and continues to increase until the larva prepares for the succeeding molt. New columnar cells are produced by divisions of the basal or interstitial cells and their transformation into columnar cells. The new cells become elongated and push between adjacent columnar cells. They continue to grow until they have reached the size of columnar cells already present. Cell multiplication and differentiation occur simultaneously, and most rapidly near the end of each instar.
The innervation of the muscle of accommodation in the eye of the teleost, Holocentrus
Authors: Meader Ralph G.
Published: February 2005

Serial sections and dissections of the eye and orbit of Holocentrus ascensionis (Osbeck) reveal a relatively well‐developed accommodation muscle (m. retractor lentis or campanula Halleri) supplied by a ramus of the short ciliary nerve which traverses the region of the vitreous humor in an invaginated fold of choroid, the processus falciformis. The ramus contains chiefly heavily myelinated nerve fibers with a few finely myelinated or unmyelinated fibers. The type, origin and probable function of these constituents follows:

Medullated postganglionic processes of ciliary ganglion cells about which end the preganglionic fibers of the oculomotor nerve.

Medullated postganglionic fibers from the trigeminal sympathetic ganglion which traverse the ciliary ganglion to join the nerve. These and (4) may supply accompanying blood vessels.

Medullated sensory fibers to the profundus ganglion.

Unmedullated or finely medullated fibers from the trigeminal sympathetic ganglion.
The effects of x‐radiation on limb development and regeneration in Amblystoma
Authors: Puckett William O.
Published: February 2005

The regeneration of the early fore limb bud of Amblystoma larvae has been prevented by exposure to x‐radiation. Histological studies show that the failure to regenerate is due to a destruction of the undifferentiated mesenchyme cells which normally furnish the materials for regeneration. Data have also been gathered as to the minimal dosage of x‐rays necessary to prevent the regeneration of the early limb bud.

By properly governed radiations the development of unamputated limb buds can also be controlled; larvae with permanent two‐, three‐ or four‐digit limbs can be produced. The effect here is primarily on the differentiation processes of the limb. These limbs in which digit formation has been controlled by x‐radiation also fail to regenerate if subsequently amputated. After amputation there is a complete dedifferentiation of all the formed structures of the limb stump. The dedifferentiated cells of the limb stump. The dedifferentiated cells of the limb stump regain their power of mitotic cell division 30 to 35 days after amputation, but are never able to differentiate into the components of a new limb. The primary effects of radiation in this case appears to be on cellular differentiation rather than on cellular proliferation.
Studies of Endamoeba blattae (Bütschli)
Authors: Morris Samuel
Published: February 2005

A detailed study of the life history and cytology of Endamoeba blattae (Bütschli, 1878) has confirmed many of the findings of earlier workers and added to the knowledge of the processes of mitosis, excystation, metacystic and later development of this animal.

Metacystic transformation has been seen to give rise to a form indistinguishable from E. thomsoni Lucas ('27). The number of chromosomes found in dividing stages of this trophozoite appears to be half that found in the large adults and indicates the possibility of a gametogenic type of reproduction differing from that described by Mercier ('10).

Upon the basis of these findings and of a reclassification of the nuclear types found among the larger endozoic amoebae, it is proposed to erect, within the genus Endamoeba Leidy (1879), three sub‐genera to serve until further knowledge permits a more permanent arrangement, as follows: Genus Endamoeba Leidy (1879). Type—E. blattae (Bütschli, 1878). Sub‐genus Endamoeba. Type—E. (E.) blattae (Bütschli, 1878). Sub‐genus Placoidia. Type—E. (P.) minchini Mackinnon ('14). Sub‐genus Poneramoeba. Type—E. (P.) histolytica Schaudinn ('03).
The jaw musculature of the phytosaur, machaeroprosopus
Authors: Anderson Howard T.
Published: February 2005

The phytosaur of the Triassic exhibits many interesting adaptive modifications of the diapsid skull. The modifications of the muscle attachment areas for the jaw muscles have been examined in comparison with the musculature of the recent forms Sphenodon and Alligator. It has been determined that the development of the fleshy anterior pterygoid and of the intramandibular muscles is an adaptation concomitant with the elongation of the snout. The modification of the temporal region in the phytosaur with the posterior extension of the squamosal is also seen to be an adaptation to gain speed in closing the great mouth. The forward position of the head‐neck joint would appear to gain advantage in the support of the heavy head. Such similarities as are seen between the phytosaur and the crocodilian may be accounted for as parallel adaptation.
The segmentation of the abdomen of Lipeurus heterographus Nitzsch (Mallophaga)
Authors: Wilson F. H.
Published: February 2005

Eleven segments are recognized in a comparative study of the abdomens in immature and adult instars of Lipeurus heterographus Nitzsch.

The abdomen of the first instar appears ten segmented but with the apparent first segment twice as long as any one of the others and with two transverse rows of hairs on the tergum while the other abdominal segments have but one. This indicates that the apparent first segment is the true first and second abdominal segments which have fused. The apparent tenth segment of the abdomen is the true eleventh segment. A fusion of the true ninth and tenth segments occurring in the third molt further reduces the number of segments to nine which is the apparent number of segments found in the adult.
A comparative study of the contents of the gelatinous accumulations of the culture media and the contents of the cytoplasm of Amoeba proteus and Arcella vulgaris
Authors: Miller E. DeWitt
Published: February 2005

Comparative data give the basis for reinterpreting alleged chromidia, mitochondria and Golgi material described for certain rhizopods.

Three distinct groups of granules can be demonstrated in both Amoeba and Arcella by techniques ordinarily employed for revealing chromatin elements of a cell, mitochondria or Golgi material. With respect to physico‐chemical properties the granules appear identical with certain forms of bacteria in the culture media. They are not destroyed by alcohol, ether, or Altmann's fluid containing 5% acetic acid.

These granules are apparently bacteria; two groups representing permanent cytoplasmic entities either as symbionts or commensals, the third possibly temporary invaders.

None of the cytoplasmic inclusions of these rhizopods have given the characteristic mitochondrial reaction when treated with Janus green. Spherules and granules, or alleged Golgi material, in Amoeba blackened with osmic acid can be revealed by techniques ordinarily employed for demonstrating the chromatin elements of a cell. Similar spherules and granules occur in the gelatinous material of the culture media, free or in bodies similar to those sometimes found in food vacuoles.

In Arcella, neutral‐red‐stainable and osmiophilic bodies, apparently identical with granules or small globules found individually distributed in the cytoplasm, can be observed both in food bodies in food vacuoles and in similar food organisms in the medium. Those occurring in the cytoplasm may represent indigestible material.
Weights and linear dimensions of the skull and some of the long bones of the skunk (Mephitis mesomelas avia)
Authors: Latimer Homer B.
Published: February 2005

The skull, mandible, atlas, scapula and the six long bones from seventy‐four male and sixty‐nine female skunk skeletons were weighed. Nine dimensions of the skull, two dimensions of the mandible and of the scapula, the length of the os coxa and the lengths of the same six long bones, were measured from 99 male and 109 female skeletons.

The weights of the skull and of the nine bones are significantly heavier in the male skunks and all but one of the linear measurements are likewise significantly greater in the males. The weights and the linear dimensions of the skull and the mandible are more variable in the males but the lengths of the long bones are more variable in the females.

The rather high positive correlations of the skull weight and the weights of the other parts of the skeleton studied, show that the weight of the skull is a good criterion of the weights of the other bones. These correlations are slightly higher in the males. The nineteen linear dimensions are likewise well correlated with the skull length. They average somewhat higher in the females.

The data on the symmetry of the paired bones are not very conclusive, but there is a preponderance of heavier and longer right bones and a crossed symmetry is suggested.
Studies on the anatomy of the respiratory system of Drosophila melanogaster
Authors: Haskins C. P. , Enzmann E. V.
Published: February 2005

A description is given of the gross anatomy of the tracheal system of the larva of Drosophila melanogaster. Comparisons of findings are made with those of Lowne for Calliphora, Wahl for Eristalis, Simms for Hylemyia, Dufour for Sarcophaga, Wandolleck for Platycephala, Trägårdh for Ephydra, and De Meijere for Lonchoptera.
Division and conjugation in Nyctotherus cordiformis (EHr.) Stein (Protozoa, Ciliata) with special reference to the nuclear phenomena
Authors: Wichterman Ralph
Published: February 2005

A cytological study of the complete life cycle of Nyctotherus cordiformis (Ehr.) Stein, a heterotrichous ciliate from the large intestine of tadpole and adult Hyla versicolor hosts is presented. In division a partial dedifferentiation of parental ingestatory structures occurs, then redifferentiation, to be retained by the anterior daughter. For the posterior daughter, the ingestatory apparatus arises de novo. In conjugation, two ciliates fuse along their peristomes. The macronucles undergoes complete fragmentation while the micronucleus divides three times. The first pregamic division results in two micronuclear products; the second division, four micronuclear products, three of which degenerate. The remaining product enters into the third pregamic division to produce the two functional, migratory and stationary, pronuclei. Interchange of migratory pronuclei follows at the fused anterior ends of the conjugants to form the amphinucleus which divides once to produce the micronucleus and the macronuclear anlage. Development and behavior of the unusual macronuclear anlage (‘spireme‐ball’ of Stein and Schneider) is described for the first time. At the end of the conjugation process, ingestatory structures of each conjugant completely dedifferentiate while a complete new set arises de novo posterior to the old ones. In this case, conjugation occurs only in tadpoles which are metamorphosing into frogs. Conjugation here is interpreted as an effort made by the ciliates to overcome a physiological crisis during the drastic host transformation changes.
The segmentary structure of the human X‐chromosome compared with that of rodents
Authors: Oguma Kan
Published: February 2005

Testicular cells obtained from Manchurians were chiefly employed for the study. In the primary spermatocyte the X‐chromosome presents a three‐segmented structure similar to that of rats. This was not clear in our previous studies, probably due to some technical failure. Of the three segments, one frequently assumes a shape suggestive of the Y‐chromosome to some authors, but this never disjoins in the first maturation division, and accordingly it cannot be regarded as a true Y. The three segments are designated as P, D1 and D2 segment, the latter two are occasionally combined to form a single D segment. The P segment presents such a great modification of shape, that it led some authors to misinterpretation. The identification of the X‐chromosome was uncertain in the spermatogonial group of chromosomes, but in every case of good fixation forty‐seven distinct chromosomes were found.
Structural and vascular changes accompanying the resorption of the proctodaeal processes after birth in the embryos of the Goodeidae, a family of viviparous fishes
Authors: Mendoza Guillermo
Published: February 2005

The types of processes encountered in the various species investigated are described. There is included the topography and structure before birth of the gonads, mesonephric ducts, urinary sinus and gut. Following birth, there are but slight changes in the topography of these organs. The most important structural change involves a complete ectodermal reconstitution of the end of the gut to form a true rectum. The vascular supply to the processes in the different species is similar and varies only in the minute details. The arterial supply is furnished by an extension of a single mesenteric artery along the gut. The number of arteries and their position at the gut opening depends on the number and position of the processes at that point. Two venous channels drain the processes; one is somatic and drains into the caudal vein, the other is visceral and empties into the hepatic portal through the subintestinal vein. The former drains the posterior process, the latter, the anterior processes. This basic pattern is constant in all species investigated. A description of the rich capillary plexus on the surface of the processes is included. With the resorption of the processes after birth, vessels that supply them become variously modified. The vein to the anterior processes and the single artery are discontinued. The vein that drains the posterior processes either disappears or is retained in part, undergoing secondary connections.
Experimental observations on the Opalinid infusorians with special reference to the influence of radium radiation upon the cytoplasmic inclusions
Authors: Horning E. S.
Published: February 2005

The cytoplasm of Opalinid infusorians contains two principal components; the mitochondria and the vegetative granules of the endoplasm. A third component in the form of Golgi bodies has been previously described. Under the influence of radium radiations the mitochondria are re‐orientated so that they assume a transverse polarity to the longitudinal axis of the organism. Later the mitochondria are segregated by the radiations so that they lie apart from the vegetative granules with which they are closely associated in the normal organism.
A cytological study of the Golgi substance of striated muscle of vertebrates
Authors: Eastlick Herbert Leonard
Published: February 2005

The silver chromate method used by Cajal, Fusari, and others supporters of the ‘network’ theory, fixes the contraction bands and (M) membranes in contracted muscle and the (Z) membranes and borders of the (Q) discs in relaxed fibers. The same structures are preserved by fixation in gold chloride. Kolatchev, and Bouin solutions. Muscle tissue subjected, prior to fixation, to fat extractives: ether, chloroform, etc., and subsequently fixed by these methods has an appearance similar to control preparations. The Cajal‐Fusari ‘network’ is therefore considered to result from an impregnation of the membranes and bands; the various types of ‘nets’ described by these observers being due to fixation of fibers in different stages of contraction.

The true Golgi substance of striated muscle consists of osmiophilic bodies located in the sarcoplasm in proximity to the nuclei. Cone, saucer, or crescent‐shaped osmiophilic bodies occur at the poles, and granules, rods or curved rods of similar staining material along the sides of the nuclei. The disposition of these structures varies from nucleus to nucleus. Heart muscle possesses a relatively larger amount of the substance than does skeletal muscle.
Studies on the amphibian digestive system. III. The origin and development of pancreatic islands in certain species of anura
Authors: Janes Ralph G.
Published: February 2005

A study is made of the pancreatic islands in Rana clamitans, R. catesbiana, R. sylvatica and Hyla versicolor during various stages of development. The islands, which were first seen in the 8‐mm. R. clamitans larvae, originate from the endodermal cells of the primitive pancreatic anlagen. Following early larval development in all of the species, new islands differentiate from the cells of the pancreatic ductules. During metamorphosis, much of the acinous tissue degenerates, but the islands persist. They become aggregated and the definitive islands are formed from the primary islands before the mature adult stage is reached.

With the azure‐eosin technique, two types of island cells were distinguishable before, or at the time of metamorphosis, in all of the anurans studied. They are designated as the red and blue types. The blue cells are considered the primitive or embryonic type, and may transform into the red type; or the red type may originate independently.
Cursorial adaptations in birds. Limb proportions in the skeleton of geococcyx
Authors: Engels William L.
Published: February 2005

Comparison of intramembral and trunk/limb proportions in the roadrunner (Geococcyx) and two related genera of cuckoos (Coccyzus and Crotophaga), together with a consideration of their habits of locomotion, lead to the following two generalizations: (1) The incipient cursorial leg of more primitive, arboreal birds, with the metatarsus shorter than the femur, is not an efficient mechanism for bipedal terrestrial locomotion. The direct adaptation to the cursorial habit in terrestrial birds lies in the further elongation of the whole leg, the distal segments undergoing a relatively greater elongation than the femur; the greatest degree of elongation is shown by the most distal segment. (2) When the development of terrestrial, cursorial habits in birds leads to diminished use, or discuse, of the wings as organs of locomotion, the wing skeleton becomes reduced in length; each segment of the wing is reduced, but the degree of reduction is greatest in the more distal segments. It is probable that reduction appears first in the most distal segment and later successively in each segment proceeding proximally therefrom.
The aortic diverticula of the Odonata
Authors: Whedon Arthur D.
Published: February 2005

Although thoracic diverticula of the aorta ending dorsally in pulsatile organs were discovered by Brocher as early as 1917 no detailed account of their structure was published. The condition of these structures in the adult was not investigated and their development through larval instars was not followed. Brocher's later papers announced the discovery of similar organs in the orders Orthoptera, Coleoptera and Lepidoptera. In 1931 E. Meyer described in some detail pulsatile organs in the Ephemerida. In general these accounts are either superficial or of doubtful interpretation.

The present paper deals with the Odonata and stresses the Anisoptera. Anax junius has been studied as the type both anatomically and histologically in all stages of larva and imago except the first four instars. Other types have been compared with Anax, and some of the other orders mentioned have been checked for presence and nature of these organs.

Aortic diverticula and pulsatile organs occur in all Odonata both larval and adult. These are derived from the same origins and their histology is that of the membranes involved in aortic and body walls. Through inference from morphology and from physiological examination it appears that pulsatile organs (1) supplement heart action, perhaps substituting for it during emergence. (2) assist in the functioning of the ostia and ostial glands, and (3) may even be important in production and distribution of hormones.
The multiple chromosomes of Paratylotropidia brunneri Scudder (Orthoptera: Acrididae)
Authors: King R. L. , Beams H. W.
Published: February 2005

There are 19 chromosomes in diploid cells of male Paratylotropidia brunneri; of these, four are V‐shaped multiples. There are twenty chromosomes in diploid cells of females; of these, four are V‐shaped multiples. If the two arms of each multiple are counted as separate chromosomes, we have the usual number of chromosomes for the Acrididae, i.e., twenty‐three in male and twenty‐four in female.

There are nine chromosomes in the first spermatocyte divisions: seven tetrads, one octad and a decad. The latter is made up of the accessory chromosome associated with an octad.

One of the V‐shaped multiples in the male is limited to that sex. The homologue of one of the dyads of which it is composed is a free dyad, the homologue of the other forms a V‐shaped multiple with the accessory chromosome. The V‐shaped multiple limited to the male shows differential heteropycosis in the prophases of the first spermatocyte. There is evidence that its homologous parts are isolated from each other as far as crossingover is concerned.

A study of the first maturation division of the heterogametic sex is essential for the identification of the sex chromosome.
Notes on the breeding habits of the nudibranchs of Monterey bay and vicinity
Authors: Costello D. P.
Published: February 2005

Data concerning the seasonal distribution of twenty‐two species of nudibranchs are recorded for a period of 9 months. The occurrence of copulation and of egg laying for these animals in the laboratory aquaria is recorded for the same period. These data indicate that the seasonal distribution of certain species is well marked, and that there is in many cases a definite breeding season.

The characteristics of the egg ribbons of these nudibranchs are described, and figured by means of photographs. These egg ribbons approach the mathematical form of a spiral of Archimedes. In every case observed, the ribbon was deposited in a counter‐clockwise direction, viewed dorsally.

The relationship between these observations and earlier work on the life histories of the nudibranchs is discussed.
Variations in the rate of mitosis in normal and colchicine‐treated tadpoles of Rana pipiens and Amblystoma jeffersonianum
Authors: Mills Katharine Olive
Published: February 2005

Study of the epidermis of Rana pipiens and Amblystoma jeffersonianum showed no variations in the mitotic rate that were correlated with the age expressed in hours after hatching or with the time of day at which the tadpoles were fixed. The average mitotic index of the epidermis during the first day of larval life was 1.88 in the frog and 1.02 in the salamander. This was correlated with the earlier developmental stage at which the frog hatched. Colchicine in concentrations above 5 × 10−4 M. in the frog and above 2.5 × 10−3 M. in the salamander arrested almost all mitoses at metaphase. Inhibition was incomplete after treatment with concentrations of 1.25 × 10−4 M. in the frog and 5 × 10−4 M. in the salamander. Severe injury was characterized by the presence of vacuolated cells with deeply stained inclusions, similar to cells found after x‐radiation. Cells continued to enter the prophase at the normal rate. The accumulation of metaphases during the first 4 hours of colchicine treatment indicated a mitotic period of about 80 minutes in the frog. During subsequent periods the expected accumulation of metaphases did not occur. It was concluded that the arrested metaphases either degenerated or passed into a resting stage without passing through anaphase.
Coherence and complexity: ambiguity and (mis)‐understanding across management teams
Authors: Cairns George , Burt George , Beech Nic
Published: February 2005

This paper examines the concept of ‘cohesion’, little discussed in management literature, and proposes the following.

Management action derived from intent towards cohesion may mitigate against the development of organizational cohesion, in that …︁

…︁ Apparent conflict between management intent and action inhibits understanding of organizational intent at senior and middle management level, with the result that …︁

…︁ The divisive response to the failed drive for unitary cohesion inhibits organizational learning.

Copyright © 2001 John Wiley & Sons, Ltd.
Influence of the intracavity second harmonic generation on the mode
competition in a double-mode diode-pumped Nd:YAG laser
Authors: Yermachenko V M , Karle R A , Petrovskiy V N , Protsenko E D
Published: February 2005

The influence of intracavity second harmonic generation
on the mode competition in a double-mode diode-pumped Nd:YAG laser
is studied theoretically and experimentally. Various
configurations of the optical cavity with II-type phase-matching
frequency-doubling crystals are considered. The conditions of
steady-state lasing and of lasing with a small level of amplitude
pulsation in the output laser beam are determined.
Fermi-Bose mapping for one-dimensional Bose gases
Authors: Yukalov V I , Girardeau M D
Published: February 2005

One-dimensional Bose gases are considered, interacting
either through the hard-core potentials or through the contact
delta potentials. Interest in these gases gained momentum because
of the recent experimental realization of quasi-one-dimensional
Bose gases in traps with tightly confined radial motion, achieving
the Tonks-Girardeau (TG) regime of strongly interacting atoms. For
such gases the Fermi-Bose mapping of wavefunctions is applicable.
The aim of the present communication is to give a brief survey of
the problem and to demonstrate the generality of this mapping by
emphasizing that: (i) It is valid for nonequilibrium
wavefunctions, described by the time-dependent Schrödinger
equation, not merely for stationary wavefunctions. (ii) It gives
the whole spectrum of all excited states, not merely the ground
state. (iii) It applies to the Lieb-Liniger gas with the contact
interaction, not merely to the TG gas of impenetrable bosons.
Observation on the incorporation cone in the rat
Authors: Shalgi Ruth , Phillips David M. , Kraicer P. F.
Published: February 2005

At the time of in vivo sperm–egg fusion in the rat, a small region of the oolemma under the head of the fertilizing sperm is observed to be free of microvilli. The microvilli‐free region increases in area, and by one hour after sperm–egg contact extends over an area 20–30 μ in circumference and bulges out to form an “incorporation cone” visible by light microscopy. The microvilli‐free incorporation cone reaches its maximum size at about two hours after sperm–egg interaction. It soon becomes smaller and has disappeared three to four hours after sperm–oocyte fusion. The cone cytoplasm is characterized by a 0.1 μ zone of thin filaments below the plasma membrane. Cytochalasin‐B, 2.5 μg/ml, prevents formation of the cone or destroys the intact cone. It is suggested that micro filaments may be involved in the formation of the incorporation cone.
The effect of in vitro storage of hamster sperm on fertilization and early development
Authors: Shaver Evelyn L. , Yanagimachi R.
Published: February 2005

The effects of storage of hamster sperm in vitro at temperatures above freezing on fertilization and early development were studied. Initially, female hamsters were inseminated artificially with epididymal sperm stored up to five days at 5°, 16°, or 23–25°C. Eggs were examined at the pronuclear stage for evidence of fertilization. The best conditions for the storage of hamster sperm were found to be 16°C in a 5% CO2 in air gas phase. Pre‐ and postimplantation development were then assessed following insemination of females with sperm stored at 16°C. An increased frequency of eggs with three pronuclei, a decrease in the number of pregnant females, and an increase in the number of resorption sites were found with increasing sperm storage time. Chromosome mosaicism and triploidy were encountered in 9.5‐day embryos resulting from eggs fertilized by stored sperm. No chromosome abnormalities were found in a control group of embryos. Thus, storage of hamster epididymal sperm resulted in decreased fertility and an increased frequency of abnormal development.
Procedures for obtaining high percentages of viable in vitro capacitated hamster sperm
Authors: Lui Chung W. , Mrsny Randall J. , Meizel Stanley
Published: February 2005

Suspensions of nearly 100% viable golden hamster sperm were prepared by passing washed cauda epididymal sperm through a column of 0.25–0.3 mm glass beads. Incubations of these viable sperm under in vitro capacitation conditions in volumes of 0.1 or 1 ml (2–2.5 × 106/ml) resulted in 85–92% viable sperm after four hours and 45 minutes of incubation. More than 70% of these sperm were judged to have been capacitated after four hours and 45 minutes of incubation on the basis of their having undergone acrosome reactions and the presence of high numbers of sperm exhibiting the activated motility characteristic of capacitated hamster sperm.

Thus, for the first time, procedures are available that will yield large numbers of viable capacitated sperm for biochemical analysis and that will also allow other studies of hamster sperm capacitation with minimum interference from molecules released from dead sperm.
Second meiotic division and polar body formation in mouse eggs fertilized in vitro
Authors: Sato Kodo , Blandau Richard J.
Published: February 2005

The second meiotic division and polar body formation in mouse eggs fertilized in vitro were observed by phase‐contrast and polarizing microscopy, and recorded by time‐lapse cinematography. Eggs were collected from oviducts of mice that had been superovulated by injections of PMS and HCG. Some eggs, inseminated with spermatozoa that had been collected from caudae epididymides of mature male mice and cultured for two to three hours before insemination, were observed continuously on a glass slide under a phase microscope. Other eggs were inseminated in Petri dishes in a 5% CO2 incubator and examined every 20 minutes for 180 minutes. Compatible results in both sets of eggs showed that formation of the second polar body began 25–40 minutes after fusion of spermatozoon with the vitellus; it was completed 40–60 minutes later; anaphase II lasted approximately five minutes before the appearance of the furrow abstricting the second polar body. It is suggested that the furrowing associated with second polar body formation is guided by the same kind of forces that divide a cell mitotically.
Differences in sperm function in vitro but not in vivo between inbred and random‐bred mice
Authors: Carey Joan E. , Olds‐Clarke Patricia
Published: February 2005

Genetic variation in spermatozoa was used to examine mechanisms important for fertilization in the mouse. A significantly greater proportion of cauda epididymal sperm from C57BL/6 (inbred) males were motile than from random‐bred (CFW) males. Random‐bred sperm, however, were able to fertilize a significantly greater percentage of eggs in vitro than were inbred sperm. When sperm of these two genotypes were used for insemination in vivo, and the penetrated eggs cultured through the first cleavage, the levels of cleavage were similar, suggesting that neither levels of sperm motility nor sperm penetration in vitro accurately reflect the ability of the same sperm populations to penetrate eggs in vivo.
Cytoskeletal and contractile proteins in coelomic oocytes, unfertilized and fertilized eggs of discoglossus pictus (Anura)
Authors: Campanella C. , Gabbiani G.
Published: February 2005

The distribution of actin, myosin, and tubulin has been investigated in coelomic oocytes, unfertilized and fertilized eggs of Discoglossus pictus utilizing: (1) immunofluorescence; (2) electron microscopy; (3) incubation with heavy meromyosin (HMM), and (4) SDS‐polyacrylamide gel electrophoresis (PAGE). In coelomic oocytes, the germinative area (GA) has long, irregular microvilli containing microfilaments. In the rest of the oocyte, the microvilli are shallow. During the transit of the oocyte in the oviduct, a dimple forms by the invagination of the GA. A palisade of microfialment bundles is present in the finger‐shaped microvilli of the dimple and extends for about 10 μm in the cytoplasm. In the rest of the egg, microvilli are absent and only random filaments appear in the cortex. Following HMM incubation, the dimple microfilaments are decorated with arrowheads pointing toward the bulk of the cytoplasm. SDS‐PAGE of egg extracts shows bands co‐migrating with actin (43K), pyruvate kinase (57K), and phosphorylase (94K). As result fertilization, the pattern of microfilament bundles in the dimple disappers in parallel with the dimple invergination itself. Generally, the entire oocyte cortex is positive to immunofluorescent staining with anti‐actin, antimyosin, and antitubulin antibodies. However, the pattern of distribution and intensity of immunofluorescent staining changes for each antiserum, during different stages. It is concluded that a contractile system is present in Discoglossus eggs, and it is particularly developed in the dimple. The dimple is probably a major compartment for the storage of unpolymerized tubulin.
Large scale isolation of bovine and pig zonae pellucidae: Chemical, immunological, and receptor properties
Authors: Gwatkin R. B. L. , Andersen O. F. , Williams D. T.
Published: February 2005

A procedure is described for isolating milligram quantities of bovine and porcine zonae pellucidae, uncontaminated by follicle cells or their processes. On SDS‐polyacrylamide gel electrophoresis the isolated bovine zona material formed one major glycoprotein band with an estimated molecular weight of approximately 100,000 daltons and two minor lower molecular weight components. The isolated pig zonae formed only one glycoprotein band with a molecular weight of approximately 62,000 daltons. Rabbit antisera raised against the isolated zonae were zona‐specific and formed only a single precipitin line against the heat‐solubilized zonae on immunoelectrophoresis. An adjuvant was not required for high‐antibody titers. High titers were also obtained by injection of the dog and rhesus monkey. Anti‐zona antibody was detected by immunofluorescence, zona‐coating, double‐immunodiffusion, and the inhibition of spermbinding to eggs, including those of human origin. Antigenic and sperm receptor properties were stable at 100°C for five minutes, but some activity was lost after longer exposure. The serum antibody produced by rabbits immunized with pig zonae was predominantly IgG and cross‐reacted with the zonae of a variety of other species, including primates. Pregnancy was inhibited in female rabbits immunized with pig zona preparations.
Ovoperoxidase activity in ionophore treated mouse eggs. II. Evidence for the enzyme's role in hardening the zona pellucida
Authors: Schmell Eli D. , Gulyas Bela J.
Published: February 2005

One consequence of fertilization or parthenogenetic activation of mammalian eggs is an altaration in the solubility proprieties of the zona pellucida, known as zona hardening. Several lines of evidence indicate that an ovoperoxidase, which is activated and/or secreted from mouse eggs. Following parthenogenetic activation, corss‐links tyrosine residues in the zona pellucida and results in hardening of the zona. First, zona hardening, as determined by decreased solubility of the zona in pronase, is inhibited by several compounds known to inhibit peroxidases. Inhibitors of hardening include phenylhydrazine, sodium sulfite, sodium azide, and glycine ethyl ester. Second, tyrosine analogs inhibit zona hardening, unless the phenolic hydroxyl group or ortho position is blocked. That is, O‐methyltyrosine (methyl substitution of phenolic hydroxyl) does not inhibit hardening; o‐methyltyrosine (methyl substitution of one ortho position) partially inhibits, whereas tyramine and N‐acetyltyrosine (free hydroxyl and ortho positions) effectively block hardening. Finally, exogenous horseradish peroxidasepromotes limited hardening of the zona in unactivated eggs. These results are consistent with a peroxidase catalyzed cross‐linking of tyrosines in the zona that results in hardening of the zona pellucida.
Mechanism of sperm‐binding inhibition by anti‐zona antisera
Authors: Aitken R. J. , Richardson D. W.
Published: February 2005

Mouse zonae pellucidae contain receptors for sperm throughout their structure since spermatozoa will bind to both the inner and outer surfaces of isolated zona fragments. Antibodies raised against mechanically isolated mouse zonae pellucidae were only capable of suppressing sperm binding to the outer zona surface in association with the formation of a precipitate in this region.

These results indicate that such antisera are not capable of interacting directly with the sperm receptors on the zona pellucida but rely upon the less efficient mechanism of steric hindrance to prevent sperm from gaining access to the sperm binding sites.
Changes in mitochondrial protein composition during testicular differentiation in mouse and bull
Authors: Hecht Norman B. , Bradley Francis M.
Published: February 2005

The morphology of testicular mitochondria changes markedly during spermatogenesis from a form normally seen in somatic cells to a “germ cell” form in which the matrix is diffuse and vacuolated and finally to a form with a condensed matrix seen in spermatozoa. Colloidal silica gel gradients and high‐resolution, two‐dimensional gel electrophoresis were used to define the changes in density and polypeptide composition that occur in testicular mitochondria during spermatogenesis. Similar densities were observed for mitochondria isolated from the same bovine or murine tissue, but mitochondria from different tissues usually had different densities. Mitochondria from testis of calf, bull, or sexually mature mouse had densities of 1.06 gm/cm3 while liver mitochondria were more dense, having a density of 1.09 gm/cm3. “Somatic‐type” testicular mitochondria from calf and “germ cell‐type” mitochondria from sexually mature mouse or bull had similar densities, 1.06 gm/cm3, while the density of mitochondria from ejaculated spermatozoa differed, ρ = 1.08 gm/cm3. Analysis of polypeptide composition of somatic and germ cell mitochondria from testes of prepuberal and sexually mature animals and from highly enriched populations of pachytene primary spermatocytes and round spermatids revealed a staining pattern of mitochondrial proteins that was markedly constant throughout development with most polypeptides being conserved and a few specific spots changing in abundance. Marked differences were detected, however, when mitochondria from ejaculated spermatozoa were compared with those from testis with many minor and major polypeptides missing and several new polypeptides present at high concentration.
On the mechanism of action of bonellin on the sea urchin egg
Authors: Cariello Lucio , Giudici Marina De Nicola , Tosti Elisabetta , Zanetti Laura
Published: February 2005

In this paper we report on the mechanism of action of bonellin on sea urchin eggs. Bonellin acts in the same way as porphyrins, ie, by causing the crosslinking of membrane proteins and the peroxocompounds formation. A possible role of membrane organization related to cleavage formation is discussed.
Use of zona‐free hamster ova to assess sperm fertilizing ability of bull and stallion
Authors: Brackett B. G. , Cofone M. A. , Boice M. L. , Bousquet D.
Published: February 2005

Zona‐free hamster ova interacted with bull and stallion spermatozoa after treatment of ejaculated semen to capacitate the sperm cells. Sperm conditioning by prolonged incubation in BWW medium (18–26 hr) prior to insemination was effective for capacitation of bull and stallion sperm. Preincubation of bull sperm for 70 or 105 min in defined medium (DM) with NaCl content elevated to result in 350 m0sM/kg also led to penetration of hamster vitelli. More rapid sperm conditioning was possible and higher proportions of interacting vitelli followed insemination with bull or stallion sperm exposed to high ionic strength DM (380–390 m0sM/kg) for 10 min before incubation in isotonic DM prior to insemination, the treatment adopted in subsequent work.

Initial efforts to assess relative fertilizing ability of freshly ejaculated semen from two fertile bulls (A and B) in A1 usage resulted in uniformly high ( > 90%) levels of sperm‐vitelli interaction (for both) when the hamster ova employed resulted from superovulation with PMSG and HCG. Following use of ova from untreated hamsters sperm samples of bull A and bull B interacted with 53.8% and 84.9% (P < 0.05) of zona‐free hamster ova, respectively. Conception data (60–90 day nonreturn rates) resulting from A1 with semen collected during the same interval but processed and stored in liquid nitrogen prior to use revealed an inverse relationship to proportions of vitelli interacting with fresh sperm; nonreturn rates were 69.3% and 66.3% for bull A and bull B, respectively. A similar treatment effected capacitation of frozen‐stored bull semen to enable sperm‐vitelli interaction. These findings encourage additional efforts to correlate testing of processed semen with fertility.
The relationship between parthenogenetic embryonic development and cumulus cell‐oocyte intercellular coupling during oocyte meiotic maturation
Authors: Eppig John J.
Published: February 2005

Intercellular coupling between cumulus cells and oocytes persists after oocyte meiotic maturation has been initiated. The experiments described here focus on the relationship between oocyte‐cumulus cell intercellular coupling during maturation and the subsequent embryonic development of spontaneous mouse parthenotes. Several lines of evidence suggest that this coupling during oocyte maturation is required for the acquisition of the capacity for spontaneous mouse parthenotes to develop embryologically. First, the period of time that LT/Sv oocytes remained coupled to cumulus cells during oocyte maturation in vivo corresponded to that required for the acquisition of the capacity for parthenogenetic embryonic development. Second, the longer that cumulus cells were present during Fpontaneous oocyte maturation in vitro, the higher was the percentageofova undergoing subsequent parthenogenetic development. Third, cumulus cell‐free oocytes cocultured with cumulus cell‐enclosed oocytes during the maturation period in vitro did not develop embryologically. Fourth, intercellular coupling between cumulus cells and oocytes persisted throughout the oocyte maturation period in vitro. Fifth, incubation of oocyte‐cumulus cell complexes in medium containing follicle‐stimulating hormone (FSH) promoted uncoupling and decreased the percentage of ova undergoing parthenogenetic development. Thus, cell‐to‐cell communication, mediated via the intercellular coupling pathway between cumulus cells and oocytes, plays an important role during oocyte maturation and relates to subsequent preimplantation development.
Requirement of extracellular calcium ions for various stages of fertilization and fertilization‐related phenomena in the hamster
Authors: Yanagimachi R.
Published: February 2005

Using a semi‐chemically defined medium, the requirement of extracellular Ca2+ for survival, capacitation, and acrosome reaction of spermatozoa as well as various stages of fertilization in the hamster was studied. A Ca2+‐deficient environment is unfavorable for long‐term survival of spermatozoa. Sperm capacitation may occur in Ca2+‐deficient media, but not as efficiently as in normal media. The acrosome reaction definitely requires extracellular Ca2+. Other processes or phenomena that require extracellular Ca2+ are initiation and maintenance of hyperactivated motility of spermatozoa, penetration of acrosome‐reacted spermatozoa into the zona pellucida, fusion of the spermatozoa with eggs, and the development of pronuclear eggs into two‐cell embryos. Extracellular Ca2+ is apparently unnecessary for the attachment of spermatozoa to the zona and egg surfaces, decondensation of the sperm nucleus, and the development of sperm and egg pronuclei within the egg. These results were compared with data obtained in other species such as the sea urchin, mouse, rat and guinea pig.