bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the fertilizing ability of spermatozoa in the epididymis of the rabbit
Authors: Bedford J. M. 
Published: June 2005

AbstractWhen spermatozoa from specific segments of the epididymis were inseminated intra‐tubally, ten hours before ovulation, virtually no ova were fertilized by sperm samples taken from the regions proximal to the middle of the corpus epididymidis. Sperm from the caput epididymidis and the proximal half of the corpus region not only fail to fertilize, but are also apparently unable to establish contact with the surface of the zona pellucida. Although a maximal fertilization rate was obtained with sperm samples from the lower part of the corpus epididymidis, significantly greater numbers of supplementary and zona surface spermatozoa were found in association with tubal ova exposed to similar numbers of sperm from the cauda epididymidis. This latter finding suggests that the cauda region contains a relatively higher percentage of mature spermatozoa, and thus that a proportion of spermatozoa do not become functionally mature until they have passed from the corpus epididymidis.Approximately 7% and 5% of ova exposed to spermatozoa from the lower corpus and cauda regions, respectively, contained three and occasionally four pronuclei, quite probably as a consequence of polyspermic fertilization. As no polyploid ova were found after similar exposure to greater numbers of ejaculated spermatozoa (Adams and Chang, '62), it is conceivable that there may be other systems on the sperm head, as well as those concerned with penetration of the zona, which also mature in some way during epididymal passage.
Structure and function in the third abdominal ganglion of the crayfish Procambarus clarkii (Girard)
Authors: Kendig Joan J. 
Published: June 2005

AbstractThe functional anatomy of the crayfish third abdominal ganglion was explored by reconstructions from silver‐stained serial sections and by intracellular recording from units in the neuropile. Fibers entering the ganglion from the ventral nerve cord and the peripheral nerves from bundales with different paths and destinations. These bundles and other anatomical features such as commissures and cell body groups are constant from animal to animal, as are the positions of individual fibers and their branches. Organization in the ganglion is not based on topographical representation of the periphery, but there is a relation between the functions of individual fibers and their positions. Some of the bundles consist of fibers with similar or related functions. The orderliness, constancy and functional relations of the anatomy point toward specific anatomical connectivity between fibers in this preparation.
Sex pheromone of the mealworm beetle. (Tenebrio molitor)
Authors: Tschinkel Walter , Willson Clyde , Bern Howard A. 
Published: June 2005

AbstractSex pheromone activity from female mealworm beetles (Tenebrio molitor) may be extracted and quantified by fractional population response of virgin adult males, which attempt copulation with any pheromone‐treated object. Extracts of mature males can be shown to elicit identical behavioral activity, although at lower individual concentration. Since response to the pheromone is sex‐specific, its apparent production by both sexes of T. molitor is especially noteworthy. It has been shown that the presence of pheromone in males cannot be due to contamination by females.Both pheromone production and the male response are undetectable in newly‐emerged adults; both rise to their maximum extent within one week of eclosion.
Flagellar Development in the Protozoan Peranema trichophorum,
Authors: Tamm Sidney L. 
Published: June 2005

AbstractChanges in flagellar length during the developmental events of flagellar replication and flagellar regeneration were investigated in single cells of the colorless euglenid flagellate Peranema trichophorum at known stages in the life cycle. The leading flagellum could be cut off at any desired length with a tungsten knife operated by a micromanipulator, and the regeneration process recorded photographically.In the regeneration of a flagellum by a postdivision cell, there is a short lag period followed by an elongation with a deceleratory rate. The relationship between elongation rate and flagellar length holds true regardless of the initial stump length. The elongation rates at given lengths are greater in predivision cells than in postdivision cells.At cell division, the parental leading flagellum rapidly shortens at a constant rate and disappears, while simultaneously two new leading flagella elongate at a deceleratory rate. Elongation continues at slower rates throughout interphase.The elongation kinetics of the flagellum during the normal cell cycle, and the kinetics of regeneration at different cell ages have been satisfactorily accounted for by a mathematical model.Shortening and elongation were compared and the relationship between them was discussed in light of the finding that shortening interrupted regeneration in some predivision cells.It was concluded that at least part of the control exerted over flagellar length changes resides in the flagellum itself.The lag period remained the same under a variety of experimental conditions, suggesting that it is a “wound healing response”.
Fine structural changes during sea urchin oogenesis
Authors: Verhey Catherine A. , Moyer Frank H. 
Published: June 2005

AbstractFine structural changes during sea urchin oogenesis are described and related to functional changes in the developing ovum. A staging sequence based on the morphology associated with the synthesis of ribosomes, cytomembranes, and yolk and cortical granule proteins is proposed: the oogonium, in which the cytoplasm contains a few scattered mitochondria, lipid inclusions and free‐floating ribosomal aggregates; the first transition stage, in which annuli form in the nuclear envelope and ribosomes become attached to newly synthesized cytomembranes; the vitellogenesis stage, in which the cytoplasm becomes packed with yolk and cortical granules, mitochondria, and lipid droplets; the second transition stage, in which annulate lamellae are delaminated from the nuclear envelope; and the mature ovum, in which the annulate lamellae are distributed throughout the cytoplasm and begin to break down into rough‐surfaced vesicles. Typical Golgi apparatus is first observed at this stage. The plasma membrane forms microvilli and there is a thick jelly layer.The association of ribosomes with cytomembranes and an amorphous material is discussed with respect to their activity in protein synthesis. The relationship of the accessory cells to the developing oocyte is also discussed.
Differential behavior of anterior and posterior embryonic chick somites in Vitro
Authors: Lash James W. 
Published: June 2005

AbstractThe posterior somites of young (stages 15–18) chick embryos have a greater chondrogenic potential in tissue culture than do the anterior somites from the same embryo. Approximately 70% of posterior somite clusters will form cartilage nodules in tissue culture, whereas only 15–20% of anterior somite clusters form nodules. Paradoxically, when randomized anterior + posterior somites are cultured together, the incidence of cartilage formation is lower than expected. Randomized anterior + posterior somite clusters have the same incidence of cartilage formation as do anterior somites alone.Somites from either region, if cultured in the presence of embryonic notochord tissue, exhibit 100% cartilage formation.The chondrogenic potential of the somites may be correlated with their histo‐architecture and their embryonic history.
Electrophoretic and kinetic properties of Rana pipiens lactate dehydrogenase isozymes
Authors: Goldberg Erwin , Wuntch Thomas 
Published: June 2005

AbstractLactate dehydrogenase of Rana pipiens exists in at least three isozymic forms. Extracts from heart tissue contain all three isozymes, and extracts from the gastrocnemius muscle contain only one isozyme. LDH extracted from testis is identical to that from the heart. The isozymes are tetramers of about 140,000 molecular weight. The five possible tetramers of LDH are not formed in frog preparations by the freeze‐thaw method applied so successfully to mammalian LDH.Kinetic data show that heart LDH exhibits substrate inhibition at lower substrate levels than does muscle LDH and that all the isozymes have a lower apparent Km value for pyruvate than for lactate.Thermal inactivation is a first order, unimolecular event with more heat energy required to inactivate the heart extract. Since inactivation of heart LDH occurred at a lower temperature and with considerably greater disruption of the molecule, the isozyme of muscle LDH has the more stable conformation.Synthesis of lactate dehydrogenase in this species appears to differ from the usual case of random association of subunits into tetramers. Homodimers may be formed first and then randomly associate to form homo‐ or hetero‐tetramers.
Selfing in Paramecium aurelia, syngen 5: Persistent instability of mating type expression
Authors: Bleyman Lea Kanner 
Published: June 2005

AbstractOne class of caryonides in stock 210, syngen 5 of P. aurelia, designated mc S, was found to be a persistent selfer. Cells of complementary mating type (IX and X) regularly appeared in cultures of the selfer caryonides. Type IX and type X cells arose independently of each other as mating reactivity began in the cultures. While the type X cells remained type X during their period of sexual reactivity, the type IX cells in some cases changed to type X. This unidirectional change of mating type in single cells occurred within an hour. Cell division was not required for the change. Under certain conditions, the expression of type IX was suppressed and cultures of mc S caryonides contained solely type X cells.Similar unidirectional changes of mating type (from odd to even) occur in other syngens of P. aurelia. In these cases, as well as in those species of ciliates where persistent selfing occurs, variable gene activity seems the most likely explanation for the unstable mating type expression.
The ontogeny of lactate dehydrogenase in the chick cornea
Authors: Alcorn S. , Maisel H. 
Published: June 2005

AbstractThe activity of the enzyme lactate dehydrogenase during development of the chick cornea was investigated by starch gel electrophoresis and by spectrophotometric analysis. The isozyme pattern of the cornea prior to the fourteenth day of incubation shows a predominance of LDH 1–3. During subsequent development, there is a marked increase in LDH 4 and 5, so that at hatching, LDH 2–5 stain with nearly equal intensity while LDH 1 shows less activity. From about ten days after hatching, the isozyme pattern is characterized by the presence of LDH 1–5 with isozymes 4 and 5 predominant as in the adult cornea. The period of increase in cathodal isozymes coincides with the time of appearance of corneal transparency, and probably reflects a change in metabolic activity occurring at this time of development.
Reduced blood supply to the uterus as a cause for early embryonic death in the mouse
Authors: Senger P. L. , Lose E. D. , Ulberg L. C. 
Published: June 2005

AbstractLimitation of blood supply to the developing embryo of the mouse was accomplished by electrocoagulation of the blood within the vessels supplying one horn of the uterus. When blockage of both the uterine artery and vein and the secondary vessels was performed before mating, 35.6% of the ova, as represented by corpora lutea (CL), were present as implantation sites at autopsy, ten days post coitum (ten days); 91.1% of the ova (CL) were present as implantation sites on the control side. During the time between electrocoagulation and mating (average, 8.3 days), some reestablishment of circulation had usually occurred. When unilateral coagulation was performed at one day and at five days, 2.6% and 14.6% of the ova, respectively, subsequently formed implantation sites.When alternate secondary branches of the uterine blood supply to one horn were coagulated at one day, 40.6% of the ova resulted in implantation sites at ten days. Tertiary arborizations of undisturbed branches appear to revascularize portions of the horn to which the blood supply had been coagulated. When blood supply to the ovarian, middle or cervical portions of the uterus was blocked at one day, 6.3%, 42.9% and 14.3% of the ova, respectively, formed implantation sites. It is suggested that the blood supply to the ovarian portion of the uterus is critical to the descending embryo.There was a significant correlation between the number of secondary vessels and the number of implantation sites in all intact uterine horns.
Environmental control of annual testicular cycles in the lizard Anolis carolinensis. I. Interaction of light and temperature in the initiation of testicular recrudescence
Authors: Licht Paul 
Published: June 2005

AbstractAdult male Anolis carolinensis were placed under several combinations of light and temperature starting in midSeptember to elucidate the environmental factors regulating the initiation of testicular recrudescence (TR). TR normally starts in the fall, proceeds gradually throughout the winter, and is completed in early spring. This pattern appears to be very similar from year to year. TR was greatly accelerated by 14 hours of light daily when body temperatures were kept constant at 32°C; or when body temperatures were fluctuated to emulate a normal thermal cycle (day 32°, night 20°). A pronounced testicular cycle occurred under the latter conditions. If the daily heating (32°) was given at night (with 20°C during the daytime) there was virtually no response to long day‐lengths. A photoperiod consisting of 12 or 6 hours of light daily, with body temperature kept constant at 32°C caused a delay in TR as compared to animals in nature or to those kept at a constant low body temperature (20°C). However, once TR began, it was accelerated by the high temperature.Photoperiods of 0 to 14 hours of light daily had no influence on the initiation or rate of TR at 20°C. Testes developed at approximately the same rate as in nature. After 150 days, the testes were unusually enlarged but spermatogenic activity was still low.These data suggest that even though a distinct photoperiodism is evident in Anolis, day‐length probably acts only in a permissive way to facilitate the temperature response which is the more direct modifier of TR. Different aspects of TR may have different thermal requirements. TR may be spontaneously initiated by an “endogenous trigger” and then modified by the thermal relations of the animal.
Congenital eye defects in the mouse. I. Corneal opacity in C57Black mice
Authors: Pierro Louis J. , Spiggle Jean 
Published: June 2005

AbstractCorneal opactities are observed in a small percentage of C57Black mice. Discrete central opacities are found in eyes of normal size; more generalized opacities are found in eyes which are reduced in size, although large enough to protrude through the eyelids. Corneas with discrete opacities are characterized by a gap in the stroma, and disorganization of the overlying epithelium. Similar stromal defects are found in corneas with more generalized opacties, and, in addition, cornea and iris are continuous along their stromal components. Either anterior polar cataract or anterior lenticonus, defects involving the anterior surface of the lens, are almost invariably found in association with the corneal opacities.Study of early lens and corneal development in C57Black embryos implicates prolonged attachment of the lens vesicle to the superficial ectoderm in the genesis of the corneal opacities. The persistence of the lens stalk serves as a barrier to migration of the mesenchyme involved in formation of the corneal stroma. Migration of the mesenchyme destined for a role in development of the stroma of the iris may also be hindered. Separation of the lens vesicle from the superficial ectoderm takes place eventually, but stromal development remains defective. Disorganization of the corneal epithelium appears to be a secondary consequence of the defective stroma. Anomalies of the anterior surface of the lens appear to result from problems associated with the abnormal separation of the lens vesicle from the superficial ectoderm.
The embryonic value of the micromeres in Ilyanassa obsoleta, as determined by deletion experiments. I. The first quartet cells
Authors: Clement Anthony C. 
Published: June 2005

AbstractEach of the first quartet micromeres of Ilyanassa obsoleta has been removed at the 8‐cell stage, and the effect of the loss observed in the larva.Removal of the 1a micromere resulted in all cases in absence of the left eye; a small reduction in size of the left lobe of the velum could frequently be detected also. In other observed details the larvae appeared complete.Absence of the 1b micromere resulted in a variable tendency toward synophthalmia, and some indication of reduction in size of the velum. Sporadic abnormalities of other types were encountered in the experimental series.Loss of the 1c micromere resulted in absence of the right eye, a slight reduction in size of the right lobe of the velum and, probably, absence of the right tentacle.Removal of the 1d micromere was without observed effect on larval structure in two out of three cases.The results are compared with deductions from cell lineage work on the related form Crepidula, and they are considered also from the standpoint of regulative capacity. The Ilyanassa embryo shows both mosaic and regulative features.
The relation between the caliber of the axon and the trophic activity of nerves in limb regeneration
Authors: Singer Marcus , Rzehak Karol , Maier Charles S. 
Published: June 2005

AbstractPrevious work from this laboratory demonstrated a relation between ability to regenerate a limb and number of nerve fibers available per unit area of amputation wound. Animals with fewer fibers than the newt, Triturus, (for example, Rana, Anolis, and Mus) do not regrow the limb. An exception appeared in Xenopus whose limb is sparsely innervated and yet which regenerates. The present work demonstrates that the nerve fibers of Xenopus make up in individual size what they lack in number. When the average cross‐sectional area of the axons was multiplied by the number of fibers per unit area, the results showed that the Xenopus limb is about as well supplied with axoplasm as that of Triturus. This was not true for Rana. The results also demonstrate for the first time a direct relation between caliber and trophic effectiveness of the axon, the evolutionary significance of which is discussed.
Studies of frog oviducal jelly secretion. I. Chemical analysis of secretory product
Authors: Lee Peter A. 
Published: June 2005

AbstractThe jelly secreted by the oviduct of Rana pipiens has been analyzed histochemically and biochemically. Histochemical techniques show that the jelly contains neutral carbohydrates and a protein moiety. Colorimetric estimation reveals that the jelly contains protein and also appreciable quantities of hexose and hexosamine. Sialic acid is present. Chromatographic methods were employed to identify the simple sugars, galactose, fucose, mannose, xylose and glucose, and the hexosamines, glucosamine and galactosamine.
Pattern variation in isogenic frogs
Authors: Casler Erika 
Published: June 2005

AbstractThe pigment patterns of groups of genetically identical individuals (clones) obtained by nuclear transfers were compared with individuals arising from normally fertilized eggs in order to ascertain the various factors involved in the formation of the wild‐type pigmentation phenotype of Rana pipiens.Thirteen experiments were performed. The froglets were killed and photographed and each picture was subjected to a number of examinations and analyses. A thorough visual examination did not reveal any clear differences between the experimental and control groups. The results of the statistical analyses were almost uniform — there was no significant difference in variability with regard to spot number, average spot size, spot location and shape, between the clones and controls. However, the individuals within the clones were more uniform in regard to the percentage area covered by the spots. In transfers involving the nuclei of few‐spotted parents into enucleated ova of few‐ and many‐spotted females, the progeny were of the nuclear type. Rank correlation analyses between parents and offspring indicated that there is a closer resemblance to the mothers than to the fathers.The results can be explained by the assumption that the genotype, environment, and chance events during development are all implicated in the production of the pigment pattern.
Cellular interactions in the development of the shell gland of the gastropod, Ilyanassa
Authors: Cather James N. 
Published: June 2005

AbstractTo determine the cell lineage of the shell gland in Ilyanassa, the 2d and 2c micromeres were marked with carbon granules. The 2d micromere derivatives form the shell gland, but 2c derivatives are later incorporated into the mantle. Deletion of 2d causes shell abnormalities but, in about 10% of the cases, the shell appears normal although somewhat small. Deletion of 2c also causes characteristic shell abnormalities. After deletion of both 2d and 2c, no shell forms. When 2c is marked and 2d deleted, the shell gland is marked. Any one‐quarter embryo can form internal shell masses. In 1013 isolated ectoblasts (−3A, −3B, −3C, −3D), no shell material formed. Ectoblast with any single macromere formed shell with good morphogenesis, as did ectoblast plus 4d. Posterior ectoblast plus 4d, equivalent in size to isolated whole ectoblast, formed external shell. Properly oriented ectoblast, grown in contact with a polar lobe, formed shell in up to 70% of the cases; in one‐half of these, the shell was external. Deletion of the macromere from an ectoblast plus 3C series of embryos at intervals through the first day resulted in embryos which did not form shell. Ectoblast in contact with polarlobe for six days, then separated, developed shell on the seventh or eighth day. (1) Neither ectoderm nor endoderm in isolation will form shell but any ectoderm‐endoderm combination has the histogenetic ability to form shell material; (2) the endoderm exerts its influence between the second and sixth days of development; (3) only those combinations including or in contat with polar lobe cytoplasm through the third quartet stage undergo normal morphogenesis; (4) transplanted polar lobes can induce ectoderm to form shell; (5) the histogenetic ability to form shell is suppressed or unactivated when polar lobe cytoplasm is present, except in the D quadrant; (6) specialization of the D quadrant is one of the major evolutionary trends in spiralians.