bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractA 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

AbstractComparison 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

AbstractAlthough 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

AbstractThere 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

AbstractData 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

AbstractStudy 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

AbstractThis 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.
Observation on the incorporation cone in the rat
Authors: Shalgi Ruth , Phillips David M. , Kraicer P. F. 
Published: February 2005

AbstractAt 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

AbstractThe 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

AbstractSuspensions 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

AbstractThe 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

AbstractGenetic 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

AbstractThe 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

AbstractA 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

AbstractOne 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

AbstractMouse 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.