bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of prolactin release and its role in color change in the teleost Gillichthys mirabilis
Authors: Sage M. 
Published: June 2005

AbstractThe degree of pigment dispersal in the xanthophores and melanophores of Gillichthys mirabilis matched the animal to its background. Hypophysectomy did not affect the melanophores, which appear to be under nervous control, but did cause concentration of the pigment in the xanthophores so that the fish could no longer adapt to a yellow background. Acetyl choline had no effect on the pigment cells but epinephrine concentrated the pigment in the melanophores. Prolactin and high doses of ACTH dispersed the pigment in the xanthophores; the main effect of ACTH was indirect and probably due to stimulation of the interrenal tissue. Cortisol dispersed pigment in the xanthophores and concentrated it in the melanophores. β‐MSH also had an indirect effect in dispersing pigment in the xanthophores. Metyrapone reduced the indirect effect of β‐MSH and ACTH but had no effect on the yellowing of fish to match a yellow background. Thus prolactin, rather than the other hormones, appears to be involved in the normal response to a yellow background. The subcutaneous implantation of a single pituitary provided sufficient hormone to affect the overlying xanthophores. Reserpine resulted in pigment dispersal in the xanthophores of intact Gillichthys but had no effect in hypophysectomized fish. This suggests that the release of prolactin is normally controlled by an inhibitory factor from the brain.
Behavioral reflexes in Rana catesbeiana and Rana clamitans with large skin grafts
Authors: Baker Robert E. 
Published: June 2005

AbstractLarge pieces of skin completely encircling the abdomen in tadpoles of Rana catesbeiana and Rana clamitans were removed, rotated through 180° and replaced. During metamorphosis animals of both species developed fore‐ and hindlimb reflex behavior in response to stimulation of the body and graft. These responses remained consistently normal throughout the experimental period and did not become maladaptive as was found to occur in a related species, Rana pipiens.The cutaneous receptive fields were mapped electrophysiologically in control and skin‐grafted Rana catesbeiana frogs and in one skin‐grafted Rana clamitans. The sizes and shapes of the receptive fields were similar to those previously reported for Rana pipiens. Unlike the receptive fields in Rana pipiens and Rana clamitans, the receptive fields examined in Rana catesbeiana readily overlapped the borders of the skin graft, innervating both normal and grafted skin.Reasons for prolonged normal behavior and cutaneous receptive field overlap in skin‐grafted Rana catesbeiana are discussed.
A re‐investigation of evidence for cholinergic neuromuscular transmission in insects
Authors: Faeder Isabelle R. , O'Brien Richard D. , Salpeter Miriam M. 
Published: June 2005

AbstractAlthough the bulk of recent evidence suggests that acetylcholine is not an excitatory transmitter at insect neuromuscular junctions, certain anomalies exist which required re‐evaluation. Several drugs affecting cholinergic transmission were studied in isolated nerve muscle preparations of adult Periplaneta americana, Gromphadorhina portentosa and Locusta migratoria and larval trunk muscle of Samia cecropia. None of the drugs studied appears to affect neuromuscular transmission in these insects. However, eserine, nicotine, and nicotine analogs produce central effects, and several drugs including succinylcholine, nicotine, nicotine analogs and eserine appear to affect motor axons at high concentrations. ACh produced no effect on isolated leg preparations of cockroaches, but did produce a transient increase of kick force in jumping leg preparations of newly molted locusts. ACh (2.5 × 10−8 − 2.5 × 10−4 M) had no effect on nerve muscle preparations of Gromphadorhina up to 20 days after nerve section, although spontaneous mechanical activity and deterioration of neuromuscular junctions were observed during this period. All preparations gave contractures to L‐glutamate (pH 7.0); the threshold (2.5 × 10−4 M) for this response did not change after denervation.
Biochemical genetics of Tribolium. I. The foundation population
Authors: Gall G. A. E. 
Published: June 2005

AbstractThe life cycle characteristics of Tribolium castaneum for body weight, RNA Concentration, soluble protein concentration and the rates of four dehydrogenases were examined using an outbred wild type stock. Average egg weight decreased until hatching occurred. Larval growth showed an exponential pattern over time reaching a maximum body size just prior to pupation (14 days). Adults increased in size only slightly.Maximum RNA and soluble protein concentrations were observed at 9 and 14 days, respectively, and decreased rapidly thereafter. Activities of glucose‐6‐phosphate, 6‐phosphogluconate, lactate and NADP‐linked isocitrate dehydrogenases also were maximal at 14 days, the time of most rapid growth rate. The data suggest a definite relational pattern between growth rate, RNA and protein synthesis at least during larval development.
Anal fin regeneration in thiouracil‐treated guppies
Authors: Hopper Arthur F. , Wallace Edith 
Published: June 2005

AbstractMale guppies were kept in a solution of 0.03% thiouracil for 45 days. At this time the gonopodium was cut back and then allowed to regenerate while the fish were maintained in one of the following solutions: (1) thiouracil, (2) aged tap water, (3) 0.01% thyroid powder, (4) 1:500,000 ethynyl testosterone, (5) ethynyl testosterone and thyroid powder, (6) ethynyl testosterone and thiouracil, (7) thyroid powder and thiouracil.Regeneration was greatly inhibited in solutions 1, 2, 5 and 7. Regeneration was normal or almost so in solutions 3, 4 and 6. It is concluded that the thiouracil‐induced inhibition of regeneration of the gonopodium of the guppy is due to the effect of thiouracil on the formation or release of testicular hormones.
Temporal effects of hormones on DNA synthesis in mouse mammary gland in vitro
Authors: El‐Darwish I. , Rivera E. M. 
Published: June 2005

AbstractMammary explants from midpregnant mice were cultured for one to five days in chemically‐defined medium containing various combinations of insulin, prolactin, and corticosterone. The influence of these hormones on DNA content and synthesis was assessed at the end of one, two, three, and five days. Explants from each culture were also examined histologically for survival and secretory responses.Insulin was primarily responsible for the stimulation of DNA synthesis. Its peak activity occurred on the first day of culture. After this time, prolactin and corticosterone interact with the tissue to maintain the insulin stimulation; prolactin's effect is manifested before that of corticosterone. The hormones in the temporal order of their effect on mammary DNA in vitro thus appear to be: insulin, prolactin, corticosterone. The histological findings indicate that secretory development occurs subsequent to cell proliferation.
Local metamorphic action of thyroxine analogues in Rana pipiens larvae,
Authors: Kaltenbach Jane Couffer 
Published: June 2005

AbstractTo determine whether or not various thyroxine analogues accelerate metamorphosis by acting directly upon target organs, analogue‐cholesterol pellets were prepared and implanted into the dorsal tail fins of Rana pipiens larvae. Many analogue implants caused localized fin resorption, a response attributed to the direct action of the analogue upon the fin. Analogues with acetic or propionic acid side chains or with an isopropyl group but no iodine atoms in the β ring were effective in lower concentrations than was thyroxine; on this basis, the most active compounds were triiodothyropropionic acid and isopropyldiiodothyronine. Fin resorption was not induced by implants of diiodophenoxyacetic acids or of dihalogenated methoxythyranilines. Yet, intraorbital implants of these compounds did stimulate glandular development in the skin dorsal to the eye (a region with a lower threshold of response to thyroxine than the tail fin). The causation of local metamorphic responses, either in the tail fin or in the orbital region, by various thyroxine analogues indicates the direct action of such compounds upon peripheral tissues of the tadpole.
Ultrastructure of rat mammary‐gland anlagen in vivo and after culture with hormones
Authors: Ceriani Roberto , Pitelka Dorothy R. , Bern Howard A. , Colley Vickie B. 
Published: June 2005

AbstractMammary gland anlagen from the 17‐day fetal rat were grown for six and nine days in organ culture in basal (Waymouth's agar) nutrient medium only and with added insulin, insulin and prolactin, or insulin, prolactin, and aldosterone. Prior work has shown that the three‐hormone combination is most effective in stimulating histologic differentiation and the synthesis of a casein‐like material. Cultured explants from each group were examined by electron microscopy and compared with 17‐day anlagen before culture and with the mammary gland of the newborn female rat. The 17‐day anlage is a solid mass of cells, surrounded by a basal lamina and a partially oriented sheath of mesenchyme cells; ultrastructure of the epithelial cells shows the characteristics of fetal tissue. At birth, the normal mammary gland consists of an extensively branching system of ductules with continuous lumina and a well developed sheath of connective tissue. Luminal surfaces of epithelial cells bear numerous microvilli and are ringed by continuous belts of tight junctions. Fat droplets are present in cells and lumina and the Golgi apparatus is abundant but not visibly active in protein secretion; rough endoplasmic reticulum is present in moderate quantity and occasionally is distended with low‐density, homogeneous content. Organ culture without hormones resulted in epithelial cell proliferation; however, the basal lamina disappeared, no connective‐tissue sheath developed, and the epithelial mass showed no organized growth pattern. Some small, true lumina appeared within the cell mass. With insulin added, the anlagen ramified moderately and formed true lumina that were distinct but often discontinuous; the enveloping connective and adipose tissues were well developed. Epithelial cells showed little organellar differentiation but contained many fat droplets and abundant glycogen. In the presence of insulin and prolactin, ductal organization was much improved, whereas organellar differentiation within epithelial cells was only slightly better than with insulin alone. With the three‐hormone combination, histologic organization and ultrastructural differentiation attained levels similar to those in the gland of the newborn rat; in addition, the Golgi complex in some cells was conspicuously active and many Golgi vesicles contained condensed material similar to the protein secretion products seen in pregnant and lactating mammary glands.
Changes in chromosomal DNA replication patterns in developing frog embryos
Authors: Stambrook P. J. , Flickinger R. A. 
Published: June 2005

AbstractContinuous exposure of embryonic explants to thymidine‐H3 was used to determine patterns of late‐replicating DNA synthesis, i.e. DNA synthesized during the last quarter of the S period, in chromosomes from different germ layers of developing frog embryos (Rana pipiens). Autoradiographic localization of silver grains over chromosomes 1, 7 and 8, as well as unkaryotyped chromosomes, revealed that patterns of late‐replicating DNA are similar in determined cells that will undergo different pathways of differentiation. In undetermined early gastrula cells and in differentiated tailbud dorsal axial cells (nerve tube, somites and notochord) more sites of DNA synthesis were late‐replicating in chromosomes 1, 7 and 8 and in unkaryotyped chromosomes than in cells of the neural plate‐dorsal mesoderm of neurulae where differentiation is occurring and in neurula endoderm where determination is taking place.
The forces involved in water uptake by the rabbit blastocyst
Authors: Tuft Peter H. , Böving Bent G. 
Published: June 2005

AbstractThe freezing point depression (ΔTf) of the plasma, uterine fluid and the fluid in the blastocyst cavity have been measured in pregnant rabbits at 4, 5, 6, 7 and 8 days post coitum. The sign and magnitude of the chemical potential gradients of water between the different compartments have been calculated from the mean values for the ΔTf. It is concluded that these gradients cannot account for the observed net water flows and that energy‐coupled processes must be involved. The energy available from respiration is far more than would be required for such energy‐coupled water flow.
Catalytic properties of the lactate dehydrogenase isozyme “X” from mouse testis
Authors: Battellino Luis J. , Blanco Antonio 
Published: June 2005

AbstractLactate dehydrogenase (LDH) isozyme 1 (B4), 5 (A4), and “X” (Testis or Sperm type) have been partially purified from mouse tissues.The following studies were carried out on the three isozymes: Km and optimum substrate concentration for pyruvate, α‐oxo‐butyrate, α‐oxo‐valerate, lactate, α‐OH‐butyrate, and α‐OH‐valerate, inhibition by substrate and product, effect of malate, N‐(4‐carboxy‐2‐hydroxyphenyl) maleimide, some citric acid cycle metabolites, urea, trypsin and pH.The mouse testicular LDH isozyme clearly differs from the common lactate dehydrogenases and from the tesficular isozymes from other species. It shows distinct sensitivity to inhibition by substrate or product whether the direct (pyruvate → lactate) or reverse reactions are studied. There is no effect of increasing concentrations of pyruvate or lactate on the direct reaction, while a clear inhibition by lactate or pyruvate is demonstrated on the reverse reaction. Citric acid cycle metabolites, specially malate and succinate, inhibit the direct reaction catalyzed by the “X” isozyme.These peculiar characteristics suggest a high degree of specialization for the principal testicular isozyme of lactate dehydrogenase.
Morphological and biophysical identification of fibrous proteins in the amniote epidermis
Authors: Baden H. P. , Maderson P. F. A. 
Published: June 2005

AbstractEpidermal material from a variety of reptilian species, avian and mammalian scales have been examined by standard histological and x‐ray diffraction techniques. It has been found that morphologic and/or tinctorial properties are not good criteria for the identification of specific fibrous protein types. The distribution of fibrous protein types in reptilian epidermal material is very variable, especially in turtles. Lepidosaurian reptiles (the tuatara, snakes and lizards) are unique in showing an alternating vertical distribution of feather and α‐type proteins over the entire body surface. The protein distribution in crocodilian scales resembles exactly that found on avian scales. Mammals only possess the α‐type protein whatever the nature of the epidermal structure of modification.
Effects of temperature, photoperiod, and hibernation on the testes of golden hamsters
Authors: Frehn John L. , Liu Chung‐Ching 
Published: June 2005

AbstractThe effects of hibernation and 1, 2, 4, 8, 12, 16, and 20 weeks of cold‐exposure (5 ± 1° C) were studied on the testes of 100 adult, male hamsters (Mesocrietus auratus, Waterhouse), having initial body weights of 80 to 100 gm. Half of these animals were maintained on an eight‐hour photoperiod and half on a 14‐hour photoperiod. Control animals, at both photoperiods, were kept at 25 ± 1° C. At the time of autopsy, the wet weights of the testes were determined and the tissue was prepared for quantitative histological evaluation (diameter of the seminiferous tubules and spermatogenic activity). In animals kept at 25° C and 14 hours of light, the testes remained unchanged. With eight hours of light at the same temperature, however, the testes: (1) were unaffected for four weeks; (2) exhibited a 90% loss in wet weight at eight weeks; and (3) recovered to about 66% of the initial level at 12 and 20 weeks. In cold‐exposed hamsters, the testes decreased rapidly in activity between two to four weeks, reaching the lowest weight at eight weeks. Those cold‐exposed animals on 14 hours of light returned to the control level by 16 weeks, but those on eight hours showed only slight recovery. The testes of the 14‐hour light, cold‐exposed animals were larger than those of the eight‐hour light, cold‐exposed animals at each week tested. Only with the 14‐hour photoperiod were the testes of the hibernators significantly smaller than those of the cold‐exposed non‐hibernators.
Partial sex reversal in adult axolotls developing from cold‐treated eggs
Authors: Brunst V. V. 
Published: June 2005

AbstractOf 12 adult (4‐year‐old) axolotls (Siredon mexicanum) develoing from cold‐treated eggs, three were originally male, and the other nine were originally female. Only two of the animals, one male and one female, were normal. The second male was underdeveloped, with very small testes and abortive development of sex cells, which included only spermatogonia. The third male was greatly underdeveloped, with vestigial testes, complete degeneration of all germ cells, and entire absence of cloacal glands.The remaining eight females were greatly underdeveloped, with ovaries of almost microscopic size and partial sex reversal. In three of these females, only male cells could be observed, and the oviducts were very much diminished. In the other five females, the sexual glands were vestiges of hermaphrodite glands, with cells of both sexes (oogonia and spermatogonia) close together.The chief abnormalities observed in the great majority of the animals, partial sex reversal and development of hermaphrodite sex glands, were evidently due to triploidy developing as a result of cold treatment of the eggs. The normal male and female were most likely diploid. The under‐developed male with only spermatogonia was probably triploid, and the male with complete degeneration of the germ cells could have been triploid. All of the females with sex reversal were undoubtedly triploid.
An autoradiographic study of sperm exchange and storage in a sea hare, Phyllaplysia taylori, a hermaphroditic gastropod (Opisthobranchia: Anaspidea)
Authors: Beeman Robert D. 
Published: June 2005

AbstractTritiated thymidine autoradiography was used to distinguish exogenous from endogenous sperm and to determine the translocations of labeled sperm within the simultaneously hermaphroditic, reciprocally copulating gastropod Phyllaplysia taylori. Heavily labeled sperm start leaving the ovotestis within 14 days after injection of H3‐thymidine. These endogenous sperm are stored, evidently less than 20 days, in the ampulla prior to copulation. During copulation the endogenous sperm are tightly bound to one another by extracellular material forming a seminal strand. This seminal strand is moved by ciliary action along the spermoviduct fold and genital groove to the tip of the extended penis. As the seminal strand issues from the tip of the labeled animal's penis into the copulatory duct of an unlabeled mate, the extracellular material of the strand dissolves, releasing the now exogenous sperm (some of which are labeled). Most of the labeled exogenous sperm are found in the seminal receptacle within two hours after copulation. Within five hours some of these sperm have become oriented with their heads buried into the receptacle lining. Surplus exogenous sperm flow into the copulatory bursa where they are destroyed.
An estradiol mitotic rate inhibiting effect in the müllerian epithelium in neonatal mice
Authors: Forsberg John‐Gunnar 
Published: June 2005

AbstractBeginning within 24 hours after birth, young mice were given daily subcutaneous injections of 5 μg estradiol‐17β in olive oil. The mice were sacrificed at varying times; six hours before death, they were given a subcutaneous injection of colchicine. The mitotic rate was studied in the epithelium in the uterine horns, uterine cervix, and müllerian vagina. Eighteen hours after the first estradiol injection, the mitotic rate was increased in the uterine epithelium, but decreased in the cervical and müllerian vaginal epithelium compared with the controls. At a continued treatment with estradiol, the mitotic rate values decreased to a level somewhat below the control level in the uterine horns; in the uterine cervix and müllerian vagina the mitotic rate decreased to very low values, significantly lower than in the corresponding regions in the controls. The mechanisms behind this mitotic rate inhibition as well as its consequences are discussed.
Temperature effects on cortical characteristics of Tetrahymena
Authors: Nanney D. L. 
Published: June 2005

AbstractCortical characteristics of new strains of Tetrahymena pyriformis of syngens 1 and 7, grown at 15°, 25° and 30°C, are compared. Although distinctions can be made in some cases, the magnitude of the difference is very small. This result suggests that natural selection is perceptive to cytogeometric details, per se, as well as sensitive to differences in the anatomy of structural molecules.
Effects of stimulation on the duration of lung ventilation in quail fetuses
Authors: Vince Margaret A. , Cheng R. C. H. 
Published: June 2005

AbstractFetuses of the bobwhite and Japanese quail were incubated for the last three days before hatching under four different conditions of stimulation: in isolation, in contact with two eggs given 24 hours more incubation, in contact with two eggs given the same amount of incubation, and in contact with two eggs given 24 hours less incubation. At the same time recordings were made of sounds produced by the experimental egg, and its respiratory movements. Measurements were then made for each experimental egg of (1) the time between the beginning of lung ventilation and the beginning of regular loud clicking, (2) the time between the beginning of regular loud clicking and hatching, and (3) the time between the beginning of lung ventilation and hatching. The two species differed slightly in that contact with other eggs reduced the duration of lung ventilation in the Japanese quail although not in the bobwhite quail; however, in both species lung ventilation varied in length according to the developmental age of the stimulating eggs. The most marked effects were obtained during the silent period of breathing before the eggs began to click. Thus the fetuses of both species apparently need to click for a definite period of time before hatching.
The DNase activities of the mouse
Authors: Ball William D. , Rutter William J. 
Published: June 2005

AbstractSeveral tissues of the mouse contain neutral DNase activity, as well as the acid DNase found in lysosomes. The mouse pancreas was found to have very low levels of neutral DNase I activity, in contrast to the high levels of DNase I measurable in bovine pancreas.On the other hand, the mouse parotid salivary gland produces large amounts of DNase I which is secreted into the saliva.The parotid DNase can be distinguished from the neutral DNase found in the liver on the basis of acid‐ and heat‐stability, and from the mouse pancreas DNase I on the basis of acid‐stability.The mouse parotid DNase I is similar to the beef pancreas DNase I in certain of its properties, but shows a distinctly different band pattern on zonal electrophoresis.It is suggested that the parotid DNase I, like the pancreatic enzymes, is a cell‐specific molecule.