bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on the fertilization block between Xenopus borealis and Xenopus laevis laevis
Authors: Brun R. , Kobel H. R. 
Published: June 2005

AbstractEggs of Xenopus borealis usually can not be fertilized by sperm of Xenopus laevis laevis, while laevis eggs do not exhibit such a fertilization block to borealis sperm. But if borealis eggs obtained from the body cavity and thus lacking jelly are enrobed with laevis jelly following transfer to the body cavity of laevis and subsequent passage through the oviduct, fertilization with laevis sperm can occur. Alternatively, laevis eggs enrobed with borealis jelly can not be usually fertilized with sperm of their own species but are still fertilized by borealis sperm. Evidence is presented that suggests that laevis sperm can not penetrate the innermost jelly layer of borealis eggs.
Polymorphism and polyploidy in the rotifer Asplanchna sieboldi: Relative nuclear DNA contents in tissues of saccate and campanulate females
Authors: Jones Philip A. , Gilbert John J. 
Published: June 2005

AbstractThe relative DNA content of nuclei from saccate and campanulate females of A. sieboldi was measured cytophotometrically. Mitotic figures from embryonic tissues of both morphotypes had similar DNA contents, indicating that both are diploid. Adult tissues were mixoploid with nuclear DNA levels characteristic of replications of the entire genome. The yolk gland nuclei showed the highest levels of ploidy (36‐ to 300‐ploid), with the greater values being restricted to the terminal regions. The gastric gland nuclei showed intermediate levels (2‐ to 50‐ploid). Oocytes were diploid and arrested in G2.
The order of tooth development and eruption in the rainbow trout (Salmo gairdneri)
Authors: Berkovitz B. K. B. 
Published: June 2005

AbstractThe ontogeny of the dentition of the rainbow trout (Salmo gairdneri) has been studied by examining serial sections of 27 hatchlings ranging in age from the day of hatching to 34 days after. By the end of the first month after hatching, the dentition of the rainbow trout consists of about 12 teeth. Though the teeth develop in rapid succession, it was possible to determine their precise sequence of development. The study showed that the teeth develop in an alternate sequence, the teeth occupying the odd‐numbered tooth positions arising first; the first tooth to develop occupied the third tooth position. The order of eruption reflected the order of initial tooth development. Occasional variations in the sequence of development were encountered. The time between initiation of these first teeth and their appearance within the oral cavity is of the order of 12 days. The teeth remain erupted for about two weeks before they are exfoliated.
Homozygous mouse embryos produced by microsurgery
Authors: Markert Clement L. , Petters Robert M. 
Published: June 2005

AbstractHomozygous mouse blastocysts have been produced following microsurgical removal of one pronucleus from the fertilized egg, diploidization in cytochalasin B, and culture in vitro. This combination of techniques should greatly shorten the time required to obtain homozygous strains of mice.
Cell interactions required for transdetermination in the imaginal leg disc of Drosophila melanogaster
Authors: Chihara Carol J. , Gerhart John C. , Lee Li‐Wen 
Published: June 2005

AbstractMale foreleg imaginal discs from late third instar larvae were cut along radii as designated on a clockface, and the sectors were tested separately for their ability to transdetermine to wing and to regenerate leg structures. The frequency of transdetermination depended strongly on the position of the cuts: discs cut into 12‐6 and 6–12 fragments or into 12‐9 and 9–12 fragments gave wing frequently, derived from the 6–12 and 9–12 fragments, respectively; whereas discs cut into 6–11 and 11‐6 fragments transdetermined rarely. Regeneration showed a different pattern, with the 6–12, 9–12 and 6–11 fragments regenerating frequently. Thus, the 6–11 fragments regenerated but did not transdetermine, indicating the separability of these two phenomena. The 12‐6 and 11‐6 fragments could be induced to transdetermine more frequently by implanting each in combination with a 6–11 piece. These results suggest that disc cells must interact with other cells not normally their neighbors in order to transdetermine, and that the transdetermining cells may be located in the upper central region of the disc.
Observations on the cortical reaction in eggs of Brachydanio rerio as seen with the scanning electron microscope
Authors: Hart Nathan H. , Yu Sui‐Foh , Greenhut Victor A. 
Published: June 2005

AbstractRipe eggs of Brachydanio rerio were fixed at selected intervals of time after activation, dechorionated, and prepared by standard techniques for viewing under the scanning electron microscope (SEM). The surfaces of eggs fixed two to four minutes after activation show all stages in the activation and extrusion of the cortical granules. At least four morphologically distinct and temporally sequential stages for the cortical granule reaction are observed with the SEM. These include the elevation of the cortical granule above the egg surface, the extrusion of the contents of the cortical granule, the transient participation of the limiting membrane of the cortical granule in egg surface membrane formation, and replacement of the granule limiting membrane by the egg plasma membrane. We propose that a consequence of egg activation is the retrieval of the cortical granule membrane.
Preliminary evidence for the intracellular localization of luteinizing hormones in mammalian oocytes
Authors: Jagiello Georgiana , Ducayen Mercedes B. 
Published: June 2005

AbstractPreliminary autoradiographic and immunofluorescent evidence is presented which suggests the localization of hLHβ, hCG and oLH within the oocytes of several mammalian species. Specificity of the response is supported by negative observations in the presence of cold hormone or antibodies to other proteins. The mechanism of action of these gonadotrophins in such a site remains to be defined.
Involvement of two carbohydrate‐containing components in the binding of uncapacitated spermatozoa to eggs of the golden hamster in vitro
Authors: Hartmann John F. , Hutchison Cameron F. 
Published: June 2005

AbstractThe mechanism by which uncapacitated epididymal sperm bind to eggs of the golden hamster in vitro has been investigated for the eventual purpose of understanding the nature of the molecular changes that the sperm surface undergoes during capacitation. It was possible to remove bound uncapacitated sperm by washing in medium supplemented with glucuronic acid; other sugars were partially effective or completely ineffective. Pretreatment of sperm with β glucuronidase prevented binding, suggesting that glucuronic acid on the sperm head is involved in binding. If sperm were allowed to bind for 25 minutes, then medium supplemented with glucuronic acid was no longer effective in removing sperm, indicating the nature of binding changes with time.Binding of uncapacitated sperm could also be prevented by removing the epididymal supernatant introduced with the sperm, but it did occur if the eggs were first treated with a purified pronase digest of epididymal supernatant. The active material appears to be oligosaccharide, very likely the carbohydrate portion of epididymal glycoproteins. Glucuronic acid could not be detected in the active fractions of the epididymal supernatant digest suggesting that the binding of uncapacitated sperm depends upon the cooperation of sperm head glucuronic acid and soluble oligosaccharide. The requirement for the soluble factor was not specific, since several glycopeptide fractions derived from pronase digests of either epididymal supernatant or the plasma glycoprotein fetuin caused uncapacitated golden hamster sperm lacking the original supernatant, to bind. However, such sperm would not bind to mouse eggs treated with these fractions.
Cardiac mutant salamanders: Evidence for heart induction
Authors: Kulikowski Robert R. , Manasek Francis J. 
Published: June 2005

AbstractHomozygosity for gene c in Ambystoma mexicanum results in no detectable heartbeat in situ. Alteration of the cardiac environment through organ culture results in rapid initiation of spontaneous heartbeat, indicating that absence of cardiac function in situ is not the result of failure of embryonic induction.
The effect of light on forelimb regeneration in the newt
Authors: Maier C. Eberhardt , Singer Marcus 
Published: June 2005

AbstractThe forelimb of the newt, Triturus (Notophthalamus) viridescens, was bilaterally amputated and the animals subjected to different photoperiods during the period of regeneration, namely (1) continuous light, (2) 15 hours of light/day and (3) total darkness. Animals exposed to continuous light reached the palette regeneration stage four to five days before those kept in total darkness with the 15 hours of light/day animals being intermediate. The difference in regeneration rate was first evident in the moderate early stage (blastema accumulation stage); it then increased during subsequent stages and the difference persisted during the observation period. In an attempt to determine whether the retina was the receptor of light affected, some animals were blinded at the time of amputation and subjected to continuous light. Their rate of regeneration was similar to sighted animals subjected to continuous light but greater than sighted animals in total darkness. The pineal is discussed as the likely mediator of the photo effect.
Orientation and behavior of epithelial cell muscle processes during Hydra budding
Authors: Otto Joann J. 
Published: June 2005

AbstractThe reorientation of the muscle processes of the ectodermal epithelial cells in Hydra attenuata has been examined during bud morphogenesis and in grafts inserted at right angles to their original orientation. The muscle processes were observed in histological preparations after staining with Mallory's Triple Stain and, in freshly fixed hydra, with polarization microscopy.Since the bud forms as an outpocketing from the parent, the ectodermal muscle processes, which run longitudinally, must reorient at some stage in order to be in the proper orientation on the bud. During the early stages of bud development, the reorientation of the ectodermal muscle processes is a passive result of the deformation of the parental tissue. Later, active reorientation occurs.The means by which muscle processes are able to reorient was studied further in rectangular grafts placed at right angles to their original orientation. In these grafts, muscle processes become aligned with those of the host in two ways: (1) in groups through the rotation of the whole graft or (2) individually, probably by retracting and then reextending in the new direction.
Oxygen consumption and activity in salamanders: Effect of body size and lunglessness
Authors: Feder Martin E. 
Published: June 2005

AbstractOxygen consumption during and after two minutes of strenuous activity was measured at 25°C in three groups of salamanders: temperate zone lunged, temperate zone lungless, and neotropical lungless. No increase in oxygen consumption was detected during two minutes of activity. There were significant differences among the three groups of salamanders in the effect of body size on maximum oxygen consumption and aerobic scope. Small lungless salamanders consumed more oxygen than small lunged salamanders; however, large lunged salamanders consumed more oxygen than large lungless salamanders. Neotropical lungless salamanders showed lower maximum oxygen consumption than temperate zone lungless salamanders, but the effect of body size was similar in these two groups. Small salamanders, both lunged and lungless, pay off oxygen debt at the same relative rate as indicated by percent of scope. Large lungless salamanders pay off debt at a slower rate than large lunged salamanders. Maximum oxygen consumption, aerobic scope, and payoff of oxygen debt are correlated with total respiratory surface area, especially at large sizes. Large lungless salamanders show a reduced capacity to transport oxygen following activity.
Insect cellular differentiation. I. Redifferentiation of the adult labial glands of Manduca sexta (lepidoptera)
Authors: Jones James E. , Hakim Raziel S. 
Published: June 2005

AbstractWith the exception of a few primitive ephemeropterans, winged insects do not normally molt as adults, although they can molt under appropriate hormonal conditions. We investigated this supernumerary molt process by taking adult labial glands (from Manduca sexta), cutting them into fragments of a single cell type, implanting them into individual freshly molted pupae, and then recovering them from pharate adult and adult hosts. The appearance and function of these fragments were compared to those of normally metamorphosing glands. Based on these criteria: (1) the supernumerary adult molt involved cellular deand re‐differentiation and (2) no transdifferentiation occurred, between the separate adult gland cell types.
Tubulin and microtubule‐like structures in mammalian acrosomes
Authors: Stambaugh R. , Smith M. 
Published: June 2005

AbstractImmunofluorescence and electron microscopy were used to demonstrate the presence of tubulin and microtubule‐like structures in rabbit and rhesus monkey sperm acrosomes. The distribution of tubulin within the acrosome appeared similar to the distribution of proteolytic activity, suggesting an association of proteinase with these structures. Electron microscopy of rhesus monkey sperm incubated in vitro demonstrated a progressive condensation of the acrosomal matrix into microtubule‐like structures. A system of this type could explain the linear patterns of silver‐proteinate staining in the penetration tunnel through the zona pellucida.
Glutamate dehydrogenase from coelenterates NADP specific
Authors: Hoffmann Richard J. , Bishop Stephen H. , Sassaman Clay 
Published: June 2005

AbstractGlutamate dehydrogenases detected in tissue extracts of a broad sample of coelenterate species all require NADP(H) as a co‐substrate, rather than being capable of using either NAD(H) or NADP(H). In this respect, the coelenterate phyla appear to be unique in the animal kingdom.
Development of the compound eyes of dragonflies (odonata). IV. Development of the adult compound eyes
Authors: Sherk Truman E. 
Published: June 2005

AbstractThe changes in the directions of view of marked larval ommatidia were observed after the emergence of the adult. Those ommatidia that had been present during the first larval instar had the most posterior directions of view in the adult visual field while the newest ommatidia that had not been functional for vision in the aquatic larva contributed to the anterior and dorsal foveas of the aerial adults.The changes in interommatidial angles at emergence are discussed. Contrary to the general trend for interommatidial angles between retained larval ommatidia to decrease at emergence, the interommatidial angles in the larval fovea of aeshnid visual predators increase at emergence.The modifications in an odonate compound eye at emergence are like an exaggeration of the modifications that occur at the moult from one larval instar to the next, except that the newest ommatidia do not have any compromises in their design for use in the aquatic vision of the larvae. This is in contrast to the ommatidia retained from the earliest larval instars which have to have the most compromises in their design so that they can be adapted for the visual requirements of every larval instar, as well as the adult. This is discussed in relation to the trend among advanced species of odonates to replace the larval ommatidia by an entirely new set of adult ommatidia.
Endocrine control of larval fat body histolysis in normal and mutant Drosophila melanogaster
Authors: Postlethwait John H. , Jones Gary J. 
Published: June 2005

AbstractIn Drosophila melanogaster, about a thousand larval fat body cells survive metamorphosis, but histolyze and disappear in the first few days of adult life. We wondered what hormonal factors control larval fat cell disappearance in normal and mutant flies. In order to test the effect of anterior endocrine organs, we isolated abdomens from the head and thorax of newly eclosed flies. In isolated abdomens fat cells disappeared at a much slower rate, decreasing by only 30% instead of 100% by 72 hours. To find if the juvenile hormone was responsible for this result, we treated isolated abdomens with ZR‐515, a juvenile hormone analogue. In ZR‐515 treated isolated abdomens, the fat cell number decreased by 94% at 72 hours. This shows that juvenile hormone activity can replace the lytic factor missing from isolated abdomens. The mutation ap4 retards the rate of fat cell lysis: only 47% of the cells disappear by 48 hours compared to 99% in heterozygous controls. To find if JH activity could restore the normal phenotype, we treated these mutants with ZR‐515. The result was that hormonetreated mutants at 48 hours had destroyed 88% of their fat cells, thereby approaching the normal situation. To study the effect of an inhibitor of protein synthesis, we injected cycloheximide into freshly eclosed normal flies. A dose of 0.3 μl of 6 × 10−4 gm/ml cycloheximide inhibited both vitellogenesis and larval fat cell disappearance. This inhibition could not be overcome by administration of ZR‐515. From these studies we conclude that juvenile hormone activity is required for larval fat cell disappearance in both wild type and mutant flies. Since cycloheximide inhibits larval fat cell disappearance even in the presence of a juvenile hormone analogue, it is suggested that the lytic effect of juvenile hormone is mediated via protein synthesis.
Effects of puromycin and actinomycin D on fertilized rabbit eggs cultured in vitro
Authors: Longo Frank J. 
Published: June 2005

AbstractRabbit zygotes were cultured in media containing varying concentrations of puromycin and actinomycin D in order to determine what effect these agents have on events of fertilization and early development. Concentrations of puromycin greater than 10−5 M inhibited mitosis, cytokinesis of fertilized eggs and leucine incorporation. In approximately 50% of the zygotes treated with puromycin (10−5 M or greater) the female pronucleus remained at its site of formation, the cortex, and did not migrate centrad. In these instances the male pronucleus moved from its site of development to the female pronucleus. Concentrations of actinomycin D greater than 10−7 M also inhibited mitosis and cytokinesis of fertilized eggs. Breakdown of the nuclear envelopes and association of the paternally‐ and maternally‐derived chromatin did not occur in either puromycinor actinomycin D‐treated embryos. Actinomycin D at all of the concentrations employed (10−9 to 10−4 M) had little effect upon the structure of nucleolus‐like bodies within male and female pronuclei. Male and female pronuclei of puromycin (10−4 M) and actinomycin D (10−5 M) treated zygotes, incubated with tritiated thymidine and prepared for scintillation counting and autoradiography, synthesized DNA at a reduced level when compared to control specimens. Although “side effects” of puromycin and actinomycin D treatment are not excluded, these results suggest that nascent proteins may be required for events of fertilization.
The possible role of hemidesmosomes in neonatally estrogen‐induced selection of a permanently altered abnormal vaginal epithelium
Authors: Cunha Gerald R. , Lee Andrew K. 
Published: June 2005

AbstractIn untreated and neonatally‐estrogenized (E) Balb/c mice the numbers of hemidesmosomes per basal cell cross section (HD/bccs) gradually increases from 0.07 HD/bccs on day 1 to about 2 to 3 HD/bccs on day 4 postpartum. In untreated mice the incidence of HD's increases and plateaus at 6 to 7 HD/bccs on days 5 and 8, while during this same period in E‐treated mice the incidence is increased to 14 to 15 HD/bccs. In 5‐day‐old E‐treated mice two types of basal vaginal epithelial cells can be recognized: basophilic cells rich in HD (19.5 ± 2.1 HD/bccs) and light cells containing only 5.3 ± 3.3 HD/bccs. The basophilic, HD‐rich cells appear to replace the lighter HD‐poor cells. The hypothesis that HD's are involved in the estradiol‐induced selection of an abnormal vaginal epithelium is discussed.
Nerve dependent macromolecular synthesis in the epidermis and blastema of the adult newt regenerate
Authors: Geraudie Jacqueline , Singer Marcus 
Published: June 2005

AbstractThe present study is an analysis of neurotrophic control of DNA and protein synthesis in the separated epidermis and blastema of the early newt limb regenerate. Previous macromolecular studies employed the entire regenerate without discrimination between its two components. The results demonstrate that the specific activities of newly synthesized protein and DNA show a nerve dependence in both epidermis and blastema. There appears to be a postdenervation rise in synthesis followed by a decline to a plateau level in both components, similar to what is reported for the whole regenerate. After two days of denervation DNA synthesis in the mesenchymatous cells is more profoundly depressed, suggesting that the epidermis is less nerve dependent.
Trophoblast regeneration by inner cell masses isolated from cultured mouse embryos
Authors: Spindle Akiko I. 
Published: June 2005

AbstractThe developmental potential of the inner cell mass (ICM) of the cultured mouse embryo was determined by testing the ability of the ICM to regenerate trophoblast in vitro. ICM's isolated by immunosurgery from either single or chimeric embryos were able to regenerate trophoblast when they were isolated at 69 hours of culture from the 2‐cell stage, but they had lost this capacity by 93 hours of culture. Trophoblast regeneration by isolated ICM's did not appear to require either a critical cell mass at the time of isolation or cell proliferation during regeneration.
Regeneration of ciliary pattern in longitudinal fragments of the hypotrichous ciliate, Stylonychia
Authors: Grimes Gary W. , Adler Joseph A. 
Published: June 2005

AbstractLongitudinal fragments of the hypotrichous ciliate Stylonychia were studied at various stages of cortical regeneration by Scanning Electron Microscopy. Analysis showed that (except for the oral primordium) all primordial fields responsible for replacing excised ciliature develop in continuity with existing primordia; i.e., all ciliary primordia are derived from segments originally continuous with the oral primordium. This observation leads to the concept of a single primordial field, a “primordium of the ciliature,” possessing the developmental competence of giving rise to a complete set of ciliary structures. Such a concept implies the operation of a reciprocal intra‐cortical communication system; i.e., the developmental manifestations of any individual primordium are determined at least in part by the precise location of morphostatic and/or primordial ciliary structures. An intra‐cortical communication system is consistent with the previously proposed “determinative region” (Grimes, '75), the function of which is to serve as the initiation site of a primordium during excystment morphogenesis.