bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth and development of chick embryo explants on various protein substrates
Authors: Klein N. W. 
Published: June 2005

AbstractChick embryo explants of 11 to 13 somites were cultured on various sources of protein in an attempt to determine if these proteins could relace the proteins of egg yolk as a nutrient substrate for the developing embryo. Various approaches were employed to provide a favorable low molecular weight supplement to the non‐yolk sources of protein. After 48 hours of cultivation, the protein nitrogen and DNA contents of the embryo and the extraembryonic membrane were determined and the stages of morphological development were estimated. The growth and development of embryos cultured on yolk or a mixture of yolk and white were not surpassed with the other sources of protein tested. However, a mixture of horse serum and ovalbumin which first had been equilibrated across a cellophane membrane with an homogenate of whole egg supported levels of embryo growth and development which closely approximated that achieved with yolk and white. Individually, serum supported the growth and development of the extraembryonic membrane while ovalbumin supported the embryo proper. The response of embryo explants to sera derived from laying hens, roosters, or rabbits was similar to that observed with horse serum. The growth of embryos provided with ovalbumin as the sole source of nitrogenous precursors was approximately double that previously achieved with a chemically defined medium containing a mixture of amino acids. Limited growth and development of embryo explants was observed with milk, casein, colostrum, and subblastodermic fluid. Bovine serum albumin and chick embryo extract failed to support embryo explants.
Experimental studies on hatching behavior in the chick. I. Thoracic spinal gaps
Authors: Oppenheim Ronald , Narayanan C. H. 
Published: June 2005

AbstractUsing microsurgical techniques spinal “gaps” were made in the thoracic level of chick embryos at two days of incubation by removing small lengths of neural tissue. These same embryos were then examined in detail between 17 days and hatching for any behavioral modifications.The frequency and patterns of various movements anterior to the gap were found to be similar to control embryos. Leg movements were also found to be equal in number to those of the controls. Operated embryos, while being able to orient correctly in the egg and to pip the shell, were not able to hatch on their own. This was due to an inability of these embryos to coordinate movements of the legs with movements anterior to the spinal gap, and to the absence of vigorous stemming movements of the legs against the shell. This prohibited them from cracking and rotating around the sell and hence from hatching.Three of the spinal embryos which were artificially hatched (pulled out of shell) were not able to stand or walk after two days. However, the legs of these chicks did show “spontaneous” alternating kicking movements and were responsive to stimulation.
Properties of intact photoreceptor cells lacking synapses
Authors: Eichenbaum Daniel M. , Goldsmith Timothy H. 
Published: June 2005

AbstractSurgically undamaged photoreceptor cells that have no connections with the central nervous system were obtained by transplanting the eye imaginal disc of third instar housefly larvae (Musca domestica) into the abdomens of host larvae and waiting for development of the host flies. Following differentiation, the photoreceptor cells of the transplants have normal cell bodies and rhabdomeres. Their axons, on the other hand, do not make synapses with higher order cells. The retinular cells, thus isolated from the optic lobe, give electrical responses to illumination that are indistinguishable from the membrane responses of normal receptor cells, and at moderate intensities of stimulation consist of an initial transient and a plateau. This graded depolarization of the soma (receptor potential) spreads electrotonically into the axon without initiating spikes. Neither CO2 nor tetrodotoxin has an effect on the receptor potential of isolated photoreceptors. The transplants dark adapt at the same rate as normal retinulae, dark adaptation being slower following longer periods of light adaptation. Clearly in flies the development of the synapses of the lamina ganglionaris is not necessary for normal physiological development of the receptors, and the responses of the photoreceptors of normal eyes can be generated without significant feedback control from the optic lobe.
The effect of sixty‐cycle AC current on the regeneration axis of Dugesia
Authors: Marsh Gordon 
Published: June 2005

AbstractDugesia dorotocephala and D. tigrina were sectioned transversely, imbedded in agar, and exposed to alternating current in a rectangular chamber. At field strengths of from 310 to 418.4 rms mv/mm potential fall, functional bipolar, regressive bipolar and permanent bipolar regenerants were produced. No regenerants showed reversal of polarity. The similarity in field strength for the three groups was primarily due to the extreme motility of imbedded pieces. The results were independent of absolute healing time and duration of exposure to the field, and of body level of regenerate origin. No significant differences were found between the species with respect to mortality or response to the AC field. AC field action is non‐polar, but its direction must coincide with the regenerant axis to be effective. The field operates to reduce the normal antero‐posterior polarity.
Mitotic patterns in the optic tectum of the chick during normal development and after early removal of the optic vesicle
Authors: Cowan W. M. , Martin A. H. , Wenger Eleanor 
Published: June 2005

AbstractThe number of mitotic figures in the optic tectum of the chick increases from just over 20, 000 on the fourth day of incubation (stages 25 and 26) to a peak of approximately 45, 000 on the fifth and sixth days (stages 28 and 29). Thereafter, the number declines sharply to about 10, 000 and 2, 000 on the eighth and ninth days respectively and to as few as 100 and 18 on the eleventh and twelfth days. The dividing cells are not uniformly distributed throughout the tectum but show a clear rostral to caudal gradient such that at every stage the number of mitoses in the caudal half of the tectum exceeds that in its rostral half. In addition the number of mitotic figures in the ventrolateral half of the tectum exceeds that in its dorsomedial half between the fourth and seventh days of incubation, but this pattern is reversed during the last few days of mitotic activity.The process of cell proliferation in the optic tectum appears to be completely independent of the developing eye since there is no significant change in either the total number of mitotic figures in the tectum, or in their spatial distribution, after complete removal of the optic vesicle towards the end of the second day of incubation.
Effects of testosterone and estrogen on spermatogenesis in Rana hexadactyla Lesson
Authors: Basu S. L. 
Published: June 2005

AbstractObservations on the normal seasonal spermatogenesis of Rana hexadactyla Lesson reveal that it is continuously cyclic nature. The effect of steroids during different times of a year on the spermatogenesis has also been studied. Testosterone treatment inhibited spermatogenesis at the secondary spermatogonial stage in all the experimental individuals. Estradiol implantation on the other hand caused a general disintegration of the tubular histoarchitecture. The probable significance of the steroid action on the seminiferous tubules and its relation with the hypophysis and the target organ are discussed.
Hormonal influence on salivary glands of chimney swift (Chaetura pelagica) in organ culture
Authors: Barnawell Earl B. 
Published: June 2005

AbstractSalivary glands from chimney swifts taken at intervals during the reproductive season were maintained in organ culture in a chemically defined medium supplemented with insulin, glucagon, prolactin, corticosterone, testosterone and crude pituitary extract in various combinations. Insulin and corticosterone or glucagon promoted survival of the tissues in vitro and insulin plus corticosterone or glucagon promoted secretory activity. Prolactin, crude pituitary extract or testosterone did not promote secretion. Essenially one hundred percent of the cultured explants survived when incubated at 37°C. However, at 44°C a large proportion of the explants failed to survive except in the presence of insulin plus corticosterone or glucagon. Prolactin did not promote survival at high incubation temperature. Hormones primarily concerned with carbohydrate metabolism appear to play an important role in in vitro survival and secretion. The appearance of secretion in vitro may be owing to the support of secretory processes initiated in vivo prior to the culture period.
Bronchial diverticula in short‐tailed shrews: Pulmonary adaptation to dust contaminated environment
Authors: Parke Wesley W. , Wetzel Ralph M. 
Published: June 2005

AbstractExamination of the lung and unusual extrapulmonary bronchial diverticula of the short‐tailed shrew (Blarina brevicauda) showed that this mammal aspirates a considerable quantity of foreign material during its constant burrowing. Experimental inhalation of an aerosol of carbon black indicated that the diverticula trapped and expelled some of the particles and may be a pulmonary adaptation to a contaminated environmental atmosphere.
The effect of light and light deprivation upon the ultrastructure of the larval mosquito eye. III. Multivesicular bodies and protein uptake
Authors: White Richard H. 
Published: June 2005

AbstractThe formation of multivesicular and lamellar bodies, organelles characteristic of arthropod photoreceptor cells, is shown in the mosquito eye to be dependent upon light. The organelles are nearly absent from light deprived eyes; they form in large numbers when such eyes are first illuminated. Multivesicular bodies form adjacent to the rhabdomere, then move proximally into the body of the cell, ultimately being transformed into lamellar and probably dense bodies. Experiments in which ferritin was injected into the hemolymph of the head confirmed the hypothesis that the coated vesicles of the rhabdomere are pinocytotic vesicles. Ferritin taken into the cell by rhabdomeric vesicles is sequestered in multivesicular bodies.
Determination of the mesonephric kidney
Authors: Etheridge Albert L. 
Published: June 2005

AbstractThe determination of the mesonephric kidney in Taricha torosa involves both inductive and suppressive interactions between the kidney mesoderm and other embryonic tissues. The analysis of kidney determination was made by explanting the mesonephrogenic mesenchyme in epidermal vesicles either alone or in combination with the endoderm, notochord, neural tube, neural crest, lateral plate mesoderm, somite or nephric duct. It was found that the endoderm, notochord, early somite, and early lateral plate mesoderm are inductors of the mesonephros. Also, both premigratory and migratory neural crest cells, neural tube, older somite, and older lateral plate mesoderm were identified as suppressors of the development of the mesonephros.Most of the above interactions occur before the nephric duct makes contact with the mesonephrogenic mesenchyme. Too much emphasis has been placed on the nephric duct as being the inductor of the mesonephros. The mesonephric kidney is determined by late tailbud stages; a result of the inductive and suppressive interactions it has experienced.
Fine structural analysis of the conjunctival papillae in the chick embryo: A reassessment of their morphogenesis and developmental significance
Authors: van de Kamp Maarten 
Published: June 2005

AbstractDevelopment and regression of the conjunctival papillae have been examined with both light and electron microscopy. The fibrous strands which extend from the papillae to the mesenchyme of the pre‐ossicular plate have been identified as collagen. Furthermore, the initial deposition of collagen fibrils has been shown to occur within channels between cells of the basal epithelium during stages 2 and 3. Bundles of collagen fibrils extend continuously from the uppermost portions of the cavity of the papilla to the mesenchyme of the condensing pre‐ossicular plate during stage 5.Degeneration is localized in a small area of the papilla during stages 3 and 4 but spreads throughout the mass during stage 5. Late in stage 5, necrotic epithelial cells are sloughed into the cavity of the papilla from its basal layer. These findings are discussed in relation to earlier light microscopic and experimental studies which have shown the papillae to be required for the subsequent development of the scleral ossicles in the subjacent mesenchyme.
Natural and immune hemagglutinin forming capacity of immature chickens
Authors: Seto Rank , Henderson W. G. 
Published: June 2005

AbstractThe level of natural hemagglutinins for several mammalian erythrocytes was low in embryos 12 to 20 days of age and in baby chicks up to two weeks of age. The antibody level increased rapidly during the third and fifth week after hatching and at a slower rate thereafter with age. The agglutinin levels were highest for rabbit and rat erythrocytes, intermediate for mouse and hamster cells, and lowest for sheep red cells.The level of immune antibody in the blood during the primary responses to sheep, mouse and hamster erythrocytes (1) reached a peak about 6 days after antigen injection, (2) was higher when antigen was injected intravenously as compared with the intraperitoneal route, (3) varied with antigen dose and, (4) increased with the age of the bird. Moreover, the antibody forming capacity was drastically reduced by x‐irradiation or cyclophosphamide treatment of embryos or baby chicks.Employing approximately optimum antigen doses, it was found that 14‐ to 18‐day embryos were unresponsive, whereas some newly hatched chicks and practically all week‐old chicks were capable of producing hemagglutinins to five mammalian erythrocytes. Associated with this change in competence, there is an increase in number of germinal centers in the spleen. The antibody forming potential increased with age, growing most rapidly during the first month and slowly thereafter. The possible relationship between the growth of the primary antibody forming potential and the occurrence of natural antibodies has been discussed.
On the rapid running of ghost crabs (Ocypode ceratophthalma)
Authors: Hafemann Dennis R. , Hubbard J. I. 
Published: June 2005

AbstractSpecimens of the ghost crab, O. ceratophthalma, ran at 1.825 ± 0.09 m/second on the sandy shore of the Flinders Islands and 2.33 ± 0.14 m/second on the deck of the R/V Alpha Helix. Specimens of Pachygrapus transversus ran at 0.92 ± 0.06 m/second on the ship's deck. Sex did not affect speed. O. ceratophthalma is anatomically and functionally specilized for running. The gait of O. ceratophthalma was recorded cinematographically and could be described by the fastest variants of the model devised by Wilson ('66) for insect walking.
The developmental genetics of polymorphism in the rotifer Asplanchna. II. A method for quantitative analysis of changes in morphogenesis induced by vitamin E, and the short‐term inheritance of the effects of vitamin E
Authors: Birky C. W. , Power Judith A. 
Published: June 2005

AbstractAmictic female Asplanchna sieboldi, reproducing asexually by diploid parthenogenesis, are predominantly saccate in form when fed paramecia. The addition of vitamin E to their diet causes their female offspring to develop regular outgrowths of the body wall, or humps. A continuous spectrum of intermediate forms connects the saccate (S) and fully humped (H) morphotypes. We have shown that this response can be studied quantitatively with the use of an ordinal scale for measuring the degree of hump development: five morphotypes are distinguished and assigned scores (S = 1; I1 = 2; I2 = 3; I3 = 4; H = 5). The response of embryos to exogenous vitamin E, measured with this scale, is proportional to the amount of vitamin E in the diet of their saccate parents. When vitamin E is removed from the diet of humped females, offspring with humps continue to be produced for up to five generations, with a gradual decline in morphotypic score. This short‐term inheritance of an environmentally‐induced trait can be explained by the passive transmission from parent to daughter of a stable endogenous inducer, which may be vitamin E itself. However, the relationship between the magnitude of the response and the concentration of this hypothetical inducer is not a simple one. For example, when females are fed vitamin E for one generation, the mean score of the granddaughters is greater than that of their daughters, which received no additional exogenous vitamin E. The same considerations apply to the inheritance of increased nuclear number in certain organs of A. brightwelli, which is another response to increased levels of dietary vitamin E.
The effects of crowding on larvae of the meal moth, Ephestia kühniella
Authors: Smith Stephen D. 
Published: June 2005

AbstractEphestia larvae of strain BII (inbred for 140 generations) were obtained at late first or early second instar, and subjected to progressively more crowded conditions. Population sets of 2, 4, 8, 16, 32, and 64 larvae were confined together. In this experiment crowding caused a diminution of body size, an apparent delay in development, and increased mortality.Experiments were also performed with sets of 64 larvae in containers with progressively greater surface area. Areas of 12.6 cm,2 and 144 cm 2 were employed. In some cases weight of food remained constant, in others, the depth. These experiments suggested that the crowding effect was not unimodal. Inhibition of body size remained, while the inhibition of development rate and mortality decreased with increased surface area.A third set of experiments measured the pO2 and pCO2 at weekly intervals in 12.6 cm 2 jars containing 4, 16, 32, and 64 larvae each, and 28.2 cm2 jars containing 64 larvae. A decrease in pO2 was found only at 14 days after isolation in the 32, 64, and 64/28.2 cm 2 jars. When jars of 64 larvae each were flushed continually with air, inhibition was not reduced. Thus the differences in pO2 were judged to be insignificant to the inhibition, and the inhibitor was judged to be non‐volatile.Mortality in the crowded populations was found to result from failure to complete eclosion by pupae behaviorally “trapped” beneath the cocoons of other larvae.
In vitro acrosome reaction and capacitation of golden hamster spermatozoa by bovine follicular fluid and its fractions
Authors: Yanagimachi R. 
Published: June 2005

AbstractUnheated bovine follicular fluid is very toxic to hamster spermatozoa. This toxicity is due to the action of globulin or globulin‐like substances in the fluid. When the fluid is pre‐treated at 56°C for about 30 minutes these spermicidal substances are detoxified, and the fluid becomes capable of inducing the acrosome reaction and capacitation of the spermatozoa. Follicular fluid contains two factors responsible for the induction of the acrosome reaction and capacitation of spermatozoa, namely the sperm‐stimulating factor and the acrosome reaction‐inducing factor. An efficient sperm acrosome reaction and capacitation can be accomplished only in the presence of these two factors. The sperm‐stimulating factor is dialyzable and heat‐stable (at 90°C). The acrosome reaction‐inducing factor, on the contrary, is non‐dialyzable and heat‐labile (at 90°C). The relationship between sperm acrosome reaction and capcitation is discussed.
The stabilization of cartilage properties in the cartilage‐forming mesenchyme of the embryonic chick limb
Authors: Searls Robert L. , Janners Martha Y. 
Published: June 2005

AbstractExperiments have been done to determine the time in the development of the embryonic chick limb when the cells in the cartilage‐forming area become “stabilized.” The particular criterion for stability used in this work was the ability of the cells to resist the influences in the limb which cause some limb mesenchyme cell to form cartilage and other limb mesenchyme cells to form soft tissue. Blocks of cartilage‐forming mesenchyme were transplanted from the cartilage‐forming area of a second limb to the prospective soft tissue area of a second limb. The host limb was permitted to develop for 48 hours, and then examined to determine if the implanted cells had formed cartilage outside of the normal cartilage pattern of the host limb. The embryos used as a source of the implanted blocks varied in stage from stage 22 to stage 27, the hosts also varied in stage from stage 22 to stage 27.It was found that a block of cartilage‐forming mesenchyme generally would conform with the host limb pattern if the donor was stage 24 or younger and the host was stage 24 or younger. A block of cartilage‐forming mesenchyme generally did not conform with the host limb pattern if the donor was stage 25 or older whatever the stage of the host. We conclude that the cartilage‐forming cells become stabilized by this criterion between stage 24 and stage 25.
Meiosis of mouse eggs before and after sperm penetration
Authors: McGaughey R. W. , Chang M. C. 
Published: June 2005

AbstractMature mice were induced to ovulate by injections of PMS and HCG and their eggs were prepared, using an air‐dry technique, for the examination of chromosomes during the first and second meiotic divisions. Sixty percent of 72 eggs recovered from follicles between 10 and 8.5 hours before ovulation were at prophase, whereas 91%–64% of 139 eggs were at metaphase I from 7 to 3 hours before ovulation. Anaphase I and telophase I were seen in 17 eggs 4.5–0 hours before ovulation. The bivalents were clumped together in a single mass at the earliest stage of diakinesis. Separate, extended bivalents which underwent contraction up to metaphase I were observed later. Counts of bivalents in 82 eggs at diakinesis and metaphase I revealed no deviation from the haploid number (n = 20). The dyads in the first polar body were usually extended and somewhat diffuse in appearance, whereas those in the egg were not. A total of 295 eggs were examined from 24 females inseminated 1.5 hours after ovulation. At 3, 3.5, 4.5 and 5.5 hours after ovulation 3%, 20%, 26% and 43% of recovered eggs respectively were penetrated by sperm, indicating that a certain length of time may be required for capacitation of mouse sperm. Approximately 90% of eggs with an intact sperm head (Type I) were at metaphase II and nearly 100% of eggs with a swollen sperm head (Types III and IV) were at telophase II. Four distinct configurations of metaphase II, “spread,” “clumped,” “compact,” and “granular” were seen in 384 unfertilized eggs recovered from 36 females at various times after induced ovulation. The haploid number of dyads was observed in all of 70 eggs counted at metaphase II in the “spread” configuration. The proportion of unfertilized eggs with a “compact” metaphase II increased from 2% at 5–7 hours to 12% at 24–31.5 hours after ovulation, while the proportion of eggs with a “granular” metaphase II increased from 11% to 47% over the same period. The second meiotic metaphase exhibited these degenerative changes mainly at the end of the fertilizable period of the egg.