bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum levels of thyroid hormone during forelimb regeneration in the adult newt, Notophthalmus viridescens
Authors: Liversage Richard A. , Korneluk Robert G. 
Published: June 2005

AbstractThe concentrations of thyroxine (T4) and triiodothyronine (T3) were determined on samples of fresh sera from adult male and female newts during the course of forelimb regeneration by means of radioimmunoassay (RIA) methods. The results show that the circulatory levels of T4 and T3 in males and females do not change significantly from those found in intact control newts as regeneration progresses. Our serum T4 values for intact adult newts are low and within the range of levels found by other investigators in various poikilotherms.
Ultrastructural characterization of the accessory lobes of Lachi (Hofmann's nuclei) in the nerve cord of the chick. II. Scanning and transmission electron microscopy with observations on the glycogen body
Authors: De Gennaro Louis D. , Benzo Camillo A. 
Published: June 2005

AbstractThe ultrastructure of the accessory lobes of Lachi (Hofmann's nuclei) and that of the glycogen body were studied by transmission and scanning electron microscopy in 1‐day‐old chicks. Glycogen cells of the accessory lobes appeared like those of the glycogen body with nuclei of similar form which were flanked by organelles and by glycogen. The predominant cell type in each structure possessed glycogen‐filled processes which were in contact with those of neighboring cells and with blood vessels throughout the tissue. The primary difference between the tissues is that the glycogen cells of the accessory lobes are associated with an extensive meshwork of nerve cells of the marginal nerve nuclei. Glycogen processes of accessory lobe cells appeared to intertwine with each other in such fashion as to completely envelop the multipolar nerve cells that are embedded in those structures. Axo‐somatic and axo‐dendritic synapses, as well as lamellar whorls were also noted in the vicinity of the perikarya of these nerve cells. The glycogen body and accessory lobes contained extensive extracellular spaces which when viewed by scanning electron microscopy appeared as sinusoid‐like networks of channels between the glycogen cells and their processes. The close proximity of these glycogen‐rich structures in the lumbosacral nerve cord and the morphological similarities shared by their cell types suggest that they have some specialized functional relationship within the avian nervous system.
Regulation of vitellogenin synthesis in Drosophila by ecdysterone and juvenile hormone
Authors: Handler Alfred M. , Postlethwait John H. 
Published: June 2005

AbstractThe hormonal regulation of vitellogenin (Vg) synthesis in Drosophila was investigated by studying the incorporation of 3H‐leucine into hemolymph proteins of normal mature females and in isolated female abdomens either untreated or treated with solutions of a juvenile hormone analog (JHA), ecdysterone, or control solutions. It was found that the synthesis of Vg was reduced in untreated isolated abdomens and in isolated abdomens treated with control solutions, but that in isolated abdomens treated with either JHA or ecdysterone, Vg synthesis was specifically stimulated.
A scanning electron microscopic study of the neural crest cell cytoskeleton after Triton X ‐ 100 demembranation
Authors: Moran Denis , Covell David , Rozos Georgia 
Published: June 2005

AbstractTriton x ‐ 100, which solubilizes cell membranes, was used to expose the detergent resistant cytoskeletal systems of cultured day 4 (angulated) and a day 8 (stellate) neural crest cells. This procedure reveals a network of fibers which correlates structurally with the morphological state of neural crest cell differentiation.
Genetic variation, cellular distribution and ontogeny of sorbitol dehydrogenase and alcohol dehydrogenase isozymes in male reproductive tissues of the mouse
Authors: Holmes Roger S. , Jones Janet T. , Peters Josephine 
Published: June 2005

AbstractCellulose acetate zymograms of alcohol dehydrogenase (ADH) and sorbitol dehydrogenase (SDH) extracted from male reproductive tissues of inbred mice were examined. ADH isozymes were differentially distributed in these tissues of C3H/He mice; ADH‐B2 was observed in all tissues and testis cellular preparations examined; ADH‐C2 was localized predominantly in the epididymis but was also present in the seminal vesicles, coagulating gland, and prostate gland. SDH was broadly distributed in these tissues but exhibited highest activities in the seminal vesicles, coagulating glands, and germinal cells of mature testes. Genetic variants for ADH‐C2 and SDH provided evidence for (1) the identity of a second form of SDH in epididymis with ADH‐C2; (2) the genetic identity of kidney, seminal vesicle, and testis SDH; and (3) the genetic identity of stomach and epididymal ADH‐C2. Developmental changes in testis and epididymal ADH isozymes during maturation were examined. ADH‐C2 appeared in the mature epididymis whereas ADH‐B2 exhibited no major changes in activity in testis and epididymis during development.
Pedal wave recovery following transection of pedal nerves in the slug,Limax maximus
Authors: Broyles James L. , Sokolove Phillip G. 
Published: June 2005

AbstractThe giant garden slug,Limax maximus, crawls by producing sequential pedal waves that propagate forward along a medial band of muscle running the full length of the foot. Nerves that originate in the pedal ganglion appear to innervate the foot musculature along its length, but not all seem to be essential for the initiation and maintenance of pedal wave activity. When nerves running backward from the pedal ganglion were transected, the portion of the sole posterior to the cut initially showed no pedal waves, and pedal waves anterior to the cut showed reduced wave velocity and frequency. After 3 to 21 days, depending primarily on how anterior the transection, fully‐formed pedal waves reappeared in the denervated region of the sole. Waves were propagated along the entire foot, but their velocity and frequency remained lower than found in normal animals or in sham‐operated controls. Methylene blue staining, and electrical stimulation and recording failed to reveal evidence of reinnervation in animals that had recovered full‐foot pedal wave activity. The results suggest that coordinated pedal waves can be maintained on parts of the sole that lack direct connections with the CNS by spread of excitation through the peripheral plexus of the foot.
A sex pheromone secreting gland in the terrestrial snail, Euhadra peliomphala
Authors: Takeda Naokuni , Tsuruoka Hitomi 
Published: June 2005

AbstractThe head‐wart found in the snail, Euhadra peliomphala, consists of a number of elevated dermal tubercles covered by a particularly thick epithelium. The head‐wart and its epithelial cells attain full size by rapid growth at the time of sexual maturation. When two snails meet in the breeding season, their head‐warts become conspicuously protuded. After touching the partner's head‐wart with large tentacles, each becomes excited, protrudes its penial mass, and finally copulates. Protrusion of the head‐wart and copulation are observed at the same time. By the use of head‐wart extract similar sexual behavior can be experimentally induced in snails. From these observations, it may be concluded that it is the epithelial surface of the head‐wart of a sexually mature snail which releases the substance that promotes sexual behavior. This physiologically active substance is considered to be a kind of sex pheromone. This pheromone does not appear to serve as a sexual attractant but serves rather to sexually excite another snail thus evoking a courtship response following their initial encounter.
Physiological asymmetry in the bilateral crusher claws of a lobster
Authors: Govind C. K. , Lang Fred 
Published: June 2005

AbstractThe American lobster, Homarus americanus which usually has dimorphic chelipeds consisting of a cutter and a crusher claw, occasionally has bilateral crusher claws. In these unusual lobsters however, only one of the paired claw behaves as a normal crusher claw. The other claw has only the appearance of a crusher claw but behaves as a cutter claw being able to close its dactyl completely in 20 msec and having short‐sarcomere, fast fibers in its closer muscle. This suggests that claw morphology and closer muscle composition are not under rigid developmental control.
The control of polarity along the anteroposterior axis in experimental chick limbs
Authors: MacCabe Jeffrey A. , Lyle Patricia S. , Lence Judy A. 
Published: June 2005

AbstractMesoderm from the posterior border of the developing limb is capable of inducing supernumerary limb outgrowth when transplanted to preaxial regions of host chick limb buds. The supernumerary limbs are always oriented with their posterior borders facing the transplant and for this reason limb tissue with this property is said to possess limb polarizing activity. Tissue excised from the preaxial border of 4‐day wing buds, having the capacity to respond to this polarizing activity, will not develop without adjacent limb polarizing tissue after transplantation to the flank of a host embryo. With polarizing tissue adjacent to one end, the responding tissue grows into a normally polarized wing tip. The responding tissue also develops if transplanted to an intact host wing bud, though not if transplanted to a wing from which the source of polarizing activity has been removed. When it is transplanted to an intact wing with its anteroposterior axis corresponding to the hosts' it develops host polarity, but when its anteroposterior axis is perpendicular to the hosts', it develops without polarity, i.e., into a symmetrical wing tip. The results suggest that an anteroposterior gradient of polarizing activity, found in the normal wing bud, is necessary for the development of polarity in these experimentally induced limbs.
Small artificial currents enhance Xenopus limb regeneration
Authors: Borgens Richard B. , Vanable Joseph W. , Jaffe Lionel F. 
Published: June 2005

AbstractA steady, small (0.1 μA) current was artificially pulled out of the end of the stumps of amputated adult Xenopus forelimbs for three to four weeks. Six months to a year later, the following responses were observed: 1. Some stimulated regenerates formed broad, flattened bifurcated structures, while sham‐treated controls formed typical hypomorphic spikes. 2. In the majority of the cathode‐stimulated regenerates, there were nerve trunks with in their cartilage core. There was no nerve in control cartilage, except in one case in which a small amount of nerve was found. Overall, the cartilage core of the stimulated regenerates had 40‐fold more nerve coursing through it than did the controls. 3. Mature thorn‐shaped epidermal papillae formed on most of the stimulated animals, but on only one of the controls. We suggest that these minute electrical currents affect regeneration by first stimulating early nerve growth.
The progesterone receptor‐like properies of Xenopus laevis oocyte melanosomes are probably due to eumelanin
Authors: Coffman Gary K. , Keem Kirsten , Smith L. Dennis 
Published: June 2005

AbstractThe binding of progesterone to the melanosomes of the Xenopus laevis oocyte was examined. Based upon the similarities between the eumelanin complex, which is prepared by stripping melanosomes of their proteins, and synthetic melanin in regard to their association with progesterone and other steroids, the data strongly suggest that eumelanin rather than a protein is responsible for the receptor‐like properties of the melanosomes.
Environmental influences on hormonally induced spermiation of the bullfrog, Rana catesbeiana
Authors: Easley Kirk A. , Culley Dudley D. , Horseman Nelson D. , Penkala Joseph E. 
Published: June 2005

AbstractFrog pituitaries, human chorionic gonadotropin (HCG), luteinizing hormone (LH), follicle stimulating hormone (FSH) and gonadotropinreleasing hormone (LH/FSH‐RH) were tested to determine their effectiveness in eliciting the spermiation response in laboratory‐reared male bullfrogs (Rana catesbeiana). LH/FSH‐RH gave the highest percentage of positive responses and the most rapid responses. Sperm acquired by cloacal sampling after LH/FSH‐RH injections were fertile.Day length (14L:10D; 8L:16D, 25°) had no measurable effect on reproductive condition, growth or sensitivity to injections of LH/FSH‐RH. Spermiation response to LH/FSH‐RH was depressed at low temperatures (15°, 20° C) and testicular recrudescence appeared to be inhibited at warm temperature (30°C). Optimum spermiation responses were obtained at 25°C.A marked daily rhythm (unimodal) of spermiation response to LH/FSH‐RH was observable. Injections given one hour before the onset and offset of a 12L:12D photoperiod (25°C) were respectively the most and least effective in stimulating spermiation. The peak and trough of the rhythm were attributed to changes in pituitary sensitivity to LH/FSH‐RH and not changes in testicular sensitivity to LH.Age and size of bullfrogs utilized in these tests had no effect on spermiation response.
Binding and redistribution of surface membrane receptors for concanavalin A on oyster hemocytes
Authors: Yoshino Timothy P. , Renwrantz Lothar R. , Cheng Thomas C. 
Published: June 2005

AbstractThe binding and redistribution of Con A surface membrane determinants was investigated in two Crassostrea virginica hemocyte subpopulations (designated LS and SS) by employing a direct Con A‐peroxidase coupling method in conjunction with light and electron microscopical cytochemistry. At 4°C small, adherent hemocytes exposed to Con A and horseradish peroxidase (HPO) produced a uniform staining pattern on hemocyte surface membranes. Polar redistribution or capping of Con A receptors was observed in 22.2% of LS and 11.0% of SS hemocytes when the incubating temperature was increased from 4 to 21°C. Receptor patching, observed with equal frequency (∼15%) in both cell subpopulations, also exhibited a temperature dependency. Capped hemocytes were readily identified by the polar concentration of darkstaining HPO reaction product along the marginal surface of each cell. Receptor patching was observed as multiple aggregates of reaction staining on blood cell surface membranes. Cap formation in SS hemocytes was inhibited by sodium azide (−N3) at each concentration of inhibitor tested. LS hemocyte capping was inhibited only at the highest −N3 concentration (5 × 10−2 M). Cells of both subpopulations were unable to completely reverse the effects of −N3 poisoning following inhibitor removal.
Age‐related changes in ovarian responsiveness to gonadotropins in normal and neonatally estrogenized mice
Authors: Mori Takao 
Published: June 2005

AbstractYoung ovariectomized mice were transplanted with ovaries obtained from either neonatally estrogenized or normal mice at different ages. Cyclic estrus ensued in 71% of the mice receiving ovarian grafts from 3‐month‐old normal donors. If donors were 12, 15 and 20 months old, cyclic estrus took place in 15, 10 and 0% of the recipients, respectively. By contrast, after transplantation of ovaries from neonatally estrogenized mice, aged 3, 12 or 15 months, cyclic estrus occurred in about 42–48% of the recipients regardless of the age of donors. Three of 17 recipients receiving ovarian grafts from 20‐month‐old neonatally estrogenized donors still showed cyclic estrus. Therefore, in neonatally estrogenized mice, decline of ovarian responsiveness to circulating gonadotropins appears to be inhibited or delayed until at least 15 months of age.
Behavioral effects of castration and testosterone propionate replacement combined with ACTH in the male domestic duck (Anas platyrhynchos L.)
Authors: Deviche Pierre 
Published: June 2005

AbstractTwenty‐one adult male ducks were bilaterally castrated, then injected as follows for 17 consecutive days: testosterone propionate (TP; N = 6; 5 mg/day/bird) + ACTH (20 IU/day/bird); TP + saline (N = 6); oil + ACTH (N = 5); oil + saline (N = 4).The birds were repeatedly observed under standardized conditions, before castration as well as during the hormonal treatments. Their behavioral performances were compared to those recorded in a sham‐operated group (N = 6).Castration resulted in a decrease of most social activities – aggressive and sexual behavior, social displays – and of the general level of activity.TP administration resulted in a complete reversal of these effects. ACTH treatment did not by itself induce any detectable change.The results are discussed in view of the present knowledge of the endocrine regulation of behavior in ducks. Evidence is also provided that individual differences in behavioral performances cannot be directly related to differences in androgen plasma levels.
Developmental changes in the pyruvate kinase isozymes of coho salmon
Authors: Guderley Helga E. , Cardenas Janet M. 
Published: June 2005

AbstractPyruvate kinase exists as two major isozymes in coho salmon. As in mammals and birds, one form is present in the early embryo and maintains a wide tissue distribution in adults. This salmonid type K shows anodal migration during electrophoresis at pH 7.5. The appearance of the second major pyruvate kinase isozyme coincides with the appearance of functional musculature in the developing embryos. In adult animals this second form is the only pyruvate kinase in muscle. Brain, kidney, liver and gill contain primarily the type K pyruvate kinase while heart contains both major forms along with three intermediate forms which presumably constitute a hybrid set. Since there is no additional isozyme restricted to gluconeogenic tissues, we conclude that a type L isozyme has not developed in these animals.The two major isozymes are immunologically distinct. Both forms are subject to fructose 1,6‐bisphosphate activation of phosphoenolpyruvate binding, but the magnitude of the effect is small. The affinities for phosphoenolpyruvate are similar, but salmon type K has hyperbolic saturation curves with this substrate and type M has sigmoidal saturation curves. While the immunological data indicates considerable divergence in structure, the kinetic parameters of the two forms have remained relatively similar.
Aerobic and anaerobic metabolism during activity in small rodents
Authors: Ruben John A. , Battalia David E. 
Published: June 2005

AbstractAnalysis of oxygen consumption and lactic acid formation during five minutes of maximal activity by the rodents Microtus montanus (Cricetidae) and Dipodomys merriami (Heteromyidae) indicates that: (1) anaerobiosis provides approximately 10% of total energy utilized during the 5‐minute activity period; (2) anaerobiosis may account for as much as one‐third of total energy utilized during the first 30 seconds of activity. In addition, these data indicate at least one species of lizard may be capable of a higher total rate of metabolism during “burst” activity than are the rodents investigated here.
A revision of the inhibitory innervation pattern of the thoracic limbs of crayfish and lobster
Authors: Hill Russell H. , Lang Fred 
Published: June 2005

AbstractABSTRACT The inhibitory innervation to the muscles of the claws and walking legs of lobsters and crayfish was investigated. In contrast to previous studies, we find that in these limbs the closer muscle shares an inhibitory axon with the bender and extensor muscles, but not with the stretcher muscle. These findings may help to explain some of the anomalous results reported by others.
Distribution of phenylalanine hydroxylase (EC 1.14.3.1) in liver and kidney of vertebrates
Authors: Hsieh Monica C. , Berry Helen K. 
Published: June 2005

AbstractThe range of phenylalanine hydroxylase activity was determined by measuring the conversion of radioactive phenylalanine to tyrosine in liver and kidney of various vertebrates. Rodents (rats, mouse, gerbil, hamster and guinea pig) were found to have the highest liver phenylalanine hydroxylase activity among all animals studied. They are also the only species that possessed a significant kidney phenylalanine hydroxylase activity which was about 25% of that found in the liver of the same animal.The synthetic dimethyl‐tetrahydro‐pteridine, used as a cofactor for the enzyme assay in most studies, catalyzed non‐enzymatic hydroxylation of phenylalanine to tyrosine. Inclusion of boiled‐blank and strict control of timing between incubation and product measurement were essential precautions to minimize erroneous results from substrate contamination and non‐enzymatic hydroxylation.
Effects of accelerating stimulation on different indices of development in Japanese quail embryos
Authors: Vince Margaret A. 
Published: June 2005

AbstractEffects of continuous accelerating stimulation on the timing, duration and rate of occurrence of different indices of development in Japanese quail embryos were examined. Indices used were: the onset of breathing and hatching, also pipping, clicking, vocalisation, membrane penetration, yolk sac withdrawal and lung aeration. Results showed that embryos stimulated by clicks began breathing about nine hours in advance of unstimulated controls and hatched about 23 hours in advance. All other indices occurred early in comparison with controls but not all occurred at the same accelerated rate and some having begun early, proceeded at the same rate as controls then were completed rapidly just before hatching. Developmental problems are discussed in the light of these results and it is suggested that continuous accelerating stimulation affects development in two main stages.
Epidermal‐dermal recombinations with embryonic naked and normal back skin of Gallus domesticus
Authors: Juran Marlane R. 
Published: June 2005

AbstractBirds exhibiting a varying featherless condition resulting from the recessive, sex‐linked gene naked (n) were used to investigate whether the gene altered the dermis or the epidermis. By splitting 7‐day normal and naked skin into its dermal and epidermal components, and heterotypically recombining and growing it in chambers on the chorio‐allantoic membrane (CAM), it was found that the epidermis of the naked birds is the site of mutant gene action. A histological study of developing normal and naked skin was done and the structure of the naked feather is elucidated.
A factor necessary for normal morphogenetic function of Anuran endoderm
Authors: Ansevin Krystyna D. , Williams Barbara J. 
Published: June 2005

AbstractCytoplasmic preparations obtained from late blastulae and early gastrulae of normal R. pipiens eggs contain factors which induce delayed lethal effects when injected into normal eggs at the beginning of cleavage. The same preparations can rescue some defective eggs which occur spontaneously (NS eggs), or are produced experimentally (ES eggs), by relieving the specific developmental syndrome displayed by either type of egg. The syndrome involves abnormal endoderm in which cytolysis is time‐programmed. The lethal factors as well as the rescue factors are absent in the normal egg cytoplasm prior to the late blastula stage.
The distribution of sorbitol dehydrogenase in embryonic and adult chicken tissues
Authors: Defabro Sofía P. , Bishop David W. , Goldemberg Adriana Lía 
Published: June 2005

AbstractSorbitol dehydrogenase activity (SDH) has been determined in various organs of embryonic and adult chickens. SDH is present in 24‐hour embryos, and its activity continues to rise during the next 48 hours. During embryonic development and after hatching, regional differences in SDH activity are demonstrable in the organs of the animal. These differences concern both level of enzyme activity and temporal changes with development. No correlation could be established between enzymatic activity and the fructose concentration of the organs studied.