bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hormonal regulation of the annual pelage color cycle in the Djungarian hamster, Phodopus sungorus. II. Role of prolactin
Authors: Duncan Marilyn J. , Goldman Bruce D. 
Published: June 2005

AbstractThis study investigated whether photoperiod‐induced changes in circulating prolactin levels, which have been observed in the Djungarian hamster (Yellon and Goldman, '83; Duncan and Goldman, '83a), might be involved in seasonal pelage color changes in this species. Injection of ovine prolactin (100 μg/day) inhibited the short photoperiod‐induced winter molt. This finding indicated that the suppression of endogenous prolactin levels normally occuring in short photoperiod‐housed hamsters (Duncan and Goldman, '83a) may induce the winter molt. Suppression of prolactin secretion with bromoergocryptine (200 μg/day) strongly inhibited the spring molt, while concomitant treatment with ovine prolactin (100 μg/day) overcame this effect of bromoergocryptine. Injection of bromoergocryptine (200 μg/day) stimulated the winter molt in castrated hamsters housed in long photoperiod; concomitant injection of prolactin (100 μg/day) reversed this effect as well. These findings strongly suggested that an increase in endogenous prolactin levels may be necessary for the development and maintenance of the summer pelage.
In vitro induction of sperm nucleus decondensation by cytosol from mature toad eggs
Authors: Iwao Yasuhiro , Katagiri Chiaki 
Published: June 2005

AbstractAn in vitro assay was performed on the cytosol from oocytes of the toad, Bufo bufo japonicus, to examine the cytoplasmic activity that induces sperm nucleus decondensation (SND). When the sperm, pretreated for 15 min with 0.05% Triton X‐100, were incubated in cytosol obtained from mature eggs (18 h post‐hormone treatment: PHT) 30–60 min after activation, their nuclei elongated and swelled markedly to take a spherical shape between 1 and 2 h after incubation. The treatment of such detergent‐treated sperm nuclei with dilute HC1 significantly enhanced this process of nuclear decondensation. The SND activity was retained in the pellet after centrifugation at 105,000g for 1 h. It was completely inhibited by EGTA (1 mM) and serine protease inhibitor (1 mM), though not at all by soybean trypsin inhibitor (1 mg/ml). The cytosol from unactivated eggs at 18 h PHT had hardly any SND activity, but was induced to exhibit a strong activity when 10 mM Ca2+ was added to the extraction medium. No SND activity was observed in the cytosol from full‐grown ovarian oocytes (0 h PHT), oocytes at the first meiotic metaphase (11 h PHT), or activated oocytes at 18 h PHT from which the germinal vesicle had been removed before the hormone treatment. Electron‐microscopic observations revealed that detergent‐ and acid‐treated sperm had completely lost their nuclear envelopes, but, after exposure to active egg cytosol, the decondensed nuclei were surrounded by continuous membranous envelopes. These results point to the importance for the formation of swollen nuclei in fertilized eggs of the membrane system in mature egg cytoplasm that may be activated by Ca2+ at the time of egg activation.
Mitochondria from the hepatopancreas of the marine clam Mercenaria mercenaria: Substrate preferences and salt and pH effects on the oxidation of palmitoyl‐L‐carnitine and succinate
Authors: Ballantyne J. S. , Storey K. B. 
Published: June 2005

AbstractA method is presented for the isolation of mitochondria with good respiratory control from the hepatopancreas of the marine clam Mercenaria mercenaria. Palmitoyl‐L‐carnitine is the preferred substrate of the mitochondria of the hepatopancreas based on state 3 rates of oxidation (in the presence of ADP). Rates of oxidation of pyruvate and glutamate were about one‐half that of the lipid substrate in state 3. α‐Glycerophosphate was oxidized at a rate about one‐third that of palmitoyl‐L‐carnitine. All Krebs cycle intermediates were oxidized to some extent. Proline was not oxidized at detectable levels. The optimal range of KCI concentrations for the oxidation of palmitoyl‐L‐carnitine is between 250 and 500 mM whereas the optimal range of KCI concentration for the oxidation of succinate is between 200 and 350 mM. The optimal range of pH for the oxidation of succinate and for the oxidation of palmitoyl‐L‐carnitine lies between pH 6.5 and 7.5 based on the respiratory control ratio.
Fish liver protein synthesis during cold acclimatization: Seasonal changes of the ultrastructure of the carp hepatocyte
Authors: Sáez Lino , Zuvić Tatiana , Amthauer Rodolfo , Rodríguez Esteban , Krauskopf Manuel 
Published: June 2005

AbstractA cell‐free system, active in protein synthesis, was constructed using ribosomes and supernatant factors isolated from the livers of winteracclimatized carps. Upon seasonal adaptation, the hepatocytes of these fishes exhibited distinctive morphological features that were not sex dependent. The cytoarchitecture of the liver cell from summer carps is consistent with the cellular arrangements found when the rate of gene expression is high. During winter, several morphological features reveal that macromolecular synthetic activity may be clearly diminished.
Inhibitory effect of acetylcholine on muscular tonus of the small intestine of a lizard
Authors: Wacyk Jurij , Guerrero Sergio , Morello Antonio 
Published: June 2005

AbstractThe present report concerns the effects of cholinergic agonists on the isometric tension of “in vitro” preparations of the esophagus and distal part of the small intestine of the lizard Liolaemus gravenhorsti.Acetylcholine (Ach) and carbachol elicited a dose‐related increase of isometric tension in the esophagus, whereas the small intestine was slowly relaxed by these drugs. Eserine induced a synergistic action on the cholinergic responses of both organs, and atropine completely antagonized the respective effects.The esophagus and the intestine showed different thresholds for the cholinergic evoked responses, the former being about 30 times more sensitive than the intestine. Assessment of cholinesterase activity revealed that Ach is hydrolyzed at a significant lesser speed in the intestine than in the esophagus.The results do not provide information about the nature of the chemical mediator causing the inhibitory effect observed in the intestine. The eventual role of an adrenergic mechanism mediated by muscarinic receptors is under study in our laboratory.
Juvenile hormone production, juvenile hormone esterase, and juvenile hormone acid methyltransferase in corpora allata of Manduca sexta
Authors: Sparagana Steven P. , Bhaskaran Govindan , Dahm Karl H. , Riddle Vicki 
Published: June 2005

AbstractJuvenile hormone (JH) secretion by corpora allata (CA) of last instar larvae of Manduca sexta was studied by measuring the rate of JH synthesis in vitro with a radiochemical assay and by analyzing JH esterase and JH acid methyltransferase (JHAMT) activities in CA. CA of 0‐day (0–12 hr after ecdysis), 4‐day (early wandering larvae), and 7‐day (prepupae) animals were used in this study.CA of 0‐day larvae showed high rates of JH synthesis, whereas CA of both 4‐and 7‐day animals did not produce detectable amounts of radiolabeled JH. JH esterase activity was absent in 0‐day CA, but high activity was present in both 4‐ and 7‐day CA. However, incubation of older CA in medium containing a potent JH esterase inhibitor did not yield radiolabeled JH, indicating that these glands are unable to methylate JH acids. This conclusion is supported by the observations that JHAMT activity was high in 0‐day CA, but absent from older CA. In view of the reported peak of JH in the hemolymph on day 7, an alternative means for producing JH is postulated.
Noninvasive pulsed doppler determination of cardiac output in an unanesthetized neotenic salamander, Ambystoma tigrinum
Authors: Hoyt Reed W. , Eldridge Marlowe , Wood Stephen C. 
Published: June 2005

AbstractA pulsed Doppler was used to determine cardiac output noninvasively in partially restrained unanesthetized neotenic tiger salamanders, Ambystoma tigrinum (mean wt. 105.0 gm ± 13.7 SD, N = 5). Although mean heart rates were similar, mean stroke volume (0.18 ml ± 0.06) and cardiac output (11.0 ml · min−1 ± 3.6) were greater than those previously reported for other amphibia. This dissimilarity is most likely due to species differences and/or the effects of anesthesia and surgical disruption of the thoracic cavity.
Exocytotic and cytolytic release of histamine from mast cells treated with Portuguese man‐of‐war (Physalia physalis) venom
Authors: Cormier Susan M. 
Published: June 2005

AbstractElectron microscopic observations suggest that venom from isolated nematocysts of the stinging tentacles of the Portuguese man‐of‐war, Physalia physalis, causes histamine release via a rapid, short‐duration exocytosis of granules and a slower, long‐duration lysis of mast cells. Fine structural changes in mast cells are concurrent with histamine release and are independent of the presence of leukocytes. Vesiculation of the plasma membrane and release of granules nearest the cell surface occur within 10 sec after exposure to 100 μg venom/105 cells. Released granules and granules retained in plasma membrane inaginations are fibrous and less electron opaque than more centrally located granules. Complex channels to the external medium continue to form, and within 1 min, characteristics of both degranulation and cytolysis are well advanced. Mitochondria are swollen or disrupted. Microridges are absent. Intracellular granules are significantly fewer in venom‐treated mast cells, but are more widely separated than in controls. This suggests that degranulation occurs at early stages but is halted as cytolysis proceeds.
In vitro effects of insulin on macromolecular events in newt limb regeneration blastemata
Authors: Vethamany‐Globus S. , Globus M. , Darch A. , Milton G. , Tomlinson B. L. 
Published: June 2005

AbstractThis work provides data demonstrating a stimulatory effect of insulin on macromolecular events occurring in cultured regeneration blastemata and demonstrates a synergistic interdependence between nerves and insulin in newt limb regeneration. The current experiments provide evidence for the following: (1) Insulin is paramount for expression of the mitogenic effect of nerves on cultured blastemata. (2) Insulin stimulates the incorporation of (3H)uridine into the acid‐insoluble fraction of blastemal homogenates, but it does not alter the turnover rate of incorporated labeled uridine. (3) Insulin also stimulates the incorporation of 35SO4 and (3H)leucine into both chondroitinase‐sensitive and chondroitinase‐resistant blastemal proteoglycans. (4) Insulin increases the uptake of radiolabeled precursors by the blastemata, namely, (3H)leucine, (3H)uridine, 35SO4, (3H)α‐aminoisobutyrate, and (3H)2‐deoxy‐D‐glucose. The importance of insulin in the regulation of newt limb regeneration is discussed.
Inability of newt epidermal cells to migrate over concanavalin A‐coated substrates
Authors: Donaldson Donald J. , Mahan James T. 
Published: June 2005

AbstractPieces of coverslip glass coated with various proteins were implanted under one edge of a fresh skin wound on adult newt hind limbs so that the implant served as wound bed for migrating epidermal cells as they attempted to form a wound epithelium. Despite the fact that concanavalin A (Con A) receptors could be demonstrated on newt epidermal cells with fluorescein isothiocyanate (FITC)‐conjugated lectin, Con A‐coated implants supported practically no migration, an even poorer response than the modest amount of migration that occurred on uncoated glass. Coomassie blue staining verified that the lectin formed a complete film over the glass, and peroxidase binding assays showed that even after several hours in the wound, the Con A binding sites for mannose were still available. Migration on fibrinogen‐coated glass (a good migration substrate) was not affected by placing the implants next to Con A‐coated implants. Thus, the failure to migrate on Con A cannot be explained by soluble Con A effects from lectin leaching off the implants. These data suggest that linkages between cell surface mannose and the substrate are not part of the strategy by which newt epidermal cells migrate.
Endogenous peroxidase in the visceral endoderm of early mouse embryos
Authors: Bałakier Hanna 
Published: June 2005

AbstractEndogenous peroxidase activity was demonstrated in early mouse embryos by means of the diaminobenzidine staining reaction. This enzyme was observed in visceral endoderm on the seventh to eighth day of gestation in vivo, but was no longer detected on the ninth day of development. In cell layers developing from blastocysts or isolated inner cell masses cultured for 96–144 h (developmental stage equivalent to 6–7.5‐day‐old embryos), diaminobenzidine product was also observed in visceral endodermal cells. Most of the endogenous peroxidase was localized inside or close to the numerous apical vacuoles in the endoderm. Ectoderm, mesoderm, ectoplacental cone, and trophoblast cells did not contain endogenous peroxidase.
The effects of products and inhibitors of arachidonic acid metabolism on the hamster sperm acrosome reaction
Authors: Meizel Stanley , Turner Kenneth O. 
Published: June 2005

AbstractABSTRACT The mammalian sperm acrosome reaction (AR) is a fusion and fenestration of sperm head membranes which is essential for fertilization. Our earlier work demonstrated that arachidonic acid could stimulate the AR 15 min after addition to hamster sperm capacitated by incubation for 4.5 h. The present study was undertaken to determine whether inhibitors of arachidonic acid metabolism could affect the stimulation of the AR by arachidonic acid and whether products of its metabolism could stimulate the AR. Phenidone or nordihydroguaiaretic acid, inhibitors of both the cyclo‐oxygenase and lipoxygenase pathways of arachidonic acid metabolism, and docosahexaenoic acid, a cylo‐oxygenase pathway inhibitor, inhibited the AR induced by arachidonic acid. PGE2, a product of the cyclo‐oxygenase pathway of arachidonic acid metabolism and 5‐ or 12‐hydroxyeicosatetraenoic acid (HETEs) products of the lipoxygenase pathway, stimulated the AR when added to sperm capacitated by incubation for 4.5 h. Prostaglandins not derived from arachidonic were also tested: PGE1 stimulated the AR, but PGF1α and PGA2 did not. We suggest that arachidonic acid metabolites produced by the sperm and by the female reproductive tract are important for the mammalian sperm AR.
A central action of octopamine on ventilation frequency in Corydalus cornutus
Authors: Bellah Karil L. , Fitch Greg K. , Kammer Ann E. 
Published: June 2005

AbstractApplication of octopamine (10−4 or 10−5 M) to ventrally dissected hellgrammites increased the frequency of the ventilatory rhythm 16.6 ± 2.0%. Similar results were observed when a chain of abdominal ganglia was isolated from other parts of the central nervous system and the periphery; thus, the effect was a central one. A ventilatory increase of similar magnitude was not elicited from chains of ganglia that lacked the dominant oscillator for the ventilatory rhythm; thus, exogenous octopamine acts at the expected site of physiological control of the rhythm. Dopamine (10−4 or 10−5 M) decreased ventilatory frequency 16.7 ± 4.0%. Thus, as in other animals (Livingstone et al., '80), a pair of amines has opposite effects on an invertebrate behavior.
Sodium balance in the American alligator
Authors: Ellis Tamir M. , Evans David H. 
Published: June 2005

AbstractAlligators in fresh water regulate their plasma and cloacal fluid electrolytes at concentrations similar to those of other crocodilians. They have an exchangeable Na pool of 60.8 μmol/gm and a unidirectional Na efflux of 3.9 μmol/100 gm·hr. Of this 11% is excreted from the cloaca, 43% presumably diffuses across the body integument, and the remaining 46% is lost from the head region. The integumental Na efflux is estimated to be 0.01 μmol/cm2·hr. In fresh water the net flux is 0.5 μmol/100 gm·hr, which suggests that nondietary Na uptake can compensate for 86% of unidirectional Na loss.
A rapid procedure for visualising the inner cell mass and trophectoderm nuclei of mouse blastocysts in situ using polynucleotide‐specific fluorochromes
Authors: Handyside Alan H. , Hunter Susan 
Published: June 2005

AbstractA rapid procedure has been devised to count the numbers of outer trophectoderm (TE) and inner cell mass (ICM) cells of mouse blastocysts by differentially labelling their nuclei in situ with polynucleotide‐specific fluorochromes. The TE nuclei were labelled with propidium iodide (PI) by permeabilising the cells using selective antibody‐mediated complement lysis (Solter and Knowles, '75). The blastocysts were then fixed in ethanol and the ICM nuclei labelled with bisbenzimide. These two fluorochromes have widely different fluorescent spectra. Thus, by using fluorescence microscopy with appropriate filter combinations, the PI‐labelled TE nuclei appeared pink or red; the bisbenzimide‐labelled ICM nuclei, blue or unlabelled.The total numbers of blastocyst nuclei and the numbers of ICM nuclei counted by differential labelling were similar to the numbers detected after spreading the nuclei of intact blastocysts or immunosurgically isolated ICMs by air‐drying (Tarkowski '66).Differential labelling of TE and ICM nuclei in situ has two important advantages—that the numbers of both these cell types can be determined for individual blastocysts and that spatial relationships are partially preserved so that regional interactions can be studied.
Evaporative water loss and skin lipids of anuran amphibians
Authors: Withers Philip C. , Hillman Stanley S. , Drewes Robert C. 
Published: June 2005

AbstractAfrican reed frogs (Hyperolius spp) and tree frogs (Chiromantis spp), an Australian tree frog (Litoria gracilenta) and a South American tree frog (Phyllomedusa azurae) have much lower rates of evaporative water loss from their dorsal skin (0.2 to 2 mg g−1 h−1) than most anuran amphibians, which evaporate water at a rate equivalent to a free water surface. Evaporative water loss rates of Chiromantis, Hyperolius, and Litoria are considerably higher when their ventral skin is exposed. Other anuran amphibians, Hylagratiosa, Agalychnis callidryas, and Afrixalus spp, appear to be moderately waterproof. The mechanism for reduction of evaporative water loss from the skin of the waterproof frogs is unclear, but it appears to involve a lipid barrier. This barrier is disrupted by treatment with a chloroform‐methanol mixture. Thin layer chromatographic analysis of lipids extracted from the dorsal and ventral skin of waterproof and nonwaterproof amphibians revealed a considerable variety of neutral and polar lipids. However, few of the lipid components were unique to the dorsal skin of waterproof frogs. We conclude that the presence per se of many of the intradermal lipids (including cholesterol, cholesterol esters, fatty acids, triglycerides, and phospholipids) is not correlated with a waterproofing barrier, although these lipids might contribute to a structural lipid barrier.
Photoperiodism in the lizard, Anolis carolinensis
Authors: Ferrell Blaine R. 
Published: June 2005

AbstractA daily rhythm of testicular photosensitivity entrained by the photoperiod of 10L:14D (light:dark) was detected in lizards at 30°C but not at 20°C. Testicular development in anoles at 30°C was stimulated by a 1‐hour light interruption occurring 16.5 hours (Experiment I) or 20 (Experiment II) after the onset of the daily photoperiod. Light interruptions occurring at other times of night tested were not stimulatory. Photoperiodism in this reptile appears to involve circadian mechanisms similar to those that have been described for members of other vertebrate classes. The expression of physiological events regulated by these mechanisms is temperature dependent.
The CO2‐specific sensitivity of hemocyanin oxygen affinity in the decapod crustaceans
Authors: Burnett Louis E. , Infantino Robert L. 
Published: June 2005

AbstractThe CO2‐specific sensitivity of hemocyanin oxygen affinity and oxygen binding site cooperativity were investigated in five species of crabs. The hypothesis that CO2‐specific effects on hemocyanin are related to the molecular CO2 concentrations that occur naturally in crab hemolymph was tested in crabs that experience a variety of hemolymph CO2 pressures. Crab species were chosen from subtidal, intertidal, and semiterrestrial habitats. Hemolymph samples from each species were added to physiological salines buffered with 50 mM HEPES. O2 equilibrium curves were determined spectrophotometrically by gassing the hemolymph‐saline mixtures with different P at constant P and temperature. We found no CO2‐specific effects on oxygen equilibrium properties of hemocyanin in any species under the conditions investigated. It is concluded that molecular CO2 and bicarbonate ions are not important in directly modulating the oxygen equilibrium properties of crustacean hemocyanins.
Earthworm leukocyte interactions during early stages of graft rejection
Authors: Cooper Edwin L. , Roch Philippe 
Published: June 2005

AbstractThe earliest phase of graft rejection in earthworms, the recognition of foreign tissue antigens, has been subjected to analysis by confronting host leukocytes with foreign erythrocytes. Only rabbit and rat erythrocytes significantly prevented healing of allografts when grafts were transplanted and erythrocytes injected simultaneously. In contrast, autografts and allografts transplanted on worms injected 1 or 2 days before grafting were never affected. Since earthworms readily produce higher titers of erythrocyte agglutinins at 24 h postinjection than at later times, we propose a hypothetical scheme of earthworm leukocyte interactions that may occur during the early phases of graft healing and of agglutinin synthesis.
Hormonal regulation of development of the interrenal activity of Δ5‐3β‐hydroxysteroid dehydrogenase in bullfrog tadpoles
Authors: Hsu Chih‐Yun , Yu Nai‐Wen , Pi Chung‐Mio , Chen Schwu‐Jen , Ruan Chih‐Chuan 
Published: June 2005

AbstractSince interrenal activity of Δ5‐3β‐hydroxysteroid dehydrogenase (Δ5‐3β‐HSD) in tadpoles during development follows the pattern of metamorphic progress (Hsu et al., '80) and Δ5‐3β‐HSD is a key enzyme in biosynthesis of corticosteroids, hypophysectomized (HX) tadpoles of Rana catesbeiana were injected with thyroxine (T4) or ACTH or T4 + ACTH. The untreated HX tadpoles served as controls. Interrenals of the four groups of tadpoles were prepared histochemically for assay of Δ5‐3β‐HSD activity. The reaction products in terms of absorbance were scanned under a defined area with a computerized microscope spectrophotometer. The results show that T4 or ACTH alone or T4 + ACTH together raised the enzyme activity above that of the controls significantly. The findings suggest an endogenous role of T4 and ACTH in development of this enzyme activity in tadpole interrenals.