bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolic alkalosis in the larval salamander, Ambystoma tigrinum: Partitioning regulatory responses between the skin and kidneys
Authors: Stiffler Daniel F. , Bachoura Norma 
Published: June 2005

AbstractLarval Ambystoma tigrinum were non‐occlusively cannulated in the truncus arteriosus for blood collection. One group was infused with a single dose of 1 ml of 200 mM NaHCO3 to induce a metabolic alkalosis. This increased pH from 7.79 to 8.22 after 5 minutes. Bicarbonate ion concentration increased from 16.3 mM to 48.6 mM during this time. After 2 h [HCO3−] was still elevated but pH had returned to control as the PCO2 became elevated. A series of infusions of 1 ml of 200 mM NaHCO3 at 40 minute intervals into a second group of animals produced a prolonged alkalosis that persisted 8 hours. During this period C1− influx increased by 130%. There was a similar increase in C1− efflux resulting in no change in net C1− flux. There was no significant change in Na+ influx, however, Na+ efflux increased by almost 150%. Bicarbonate fluxes were measured directly in a third group of serially infused animals whose cloacae were cannulated to permit partitioning of renal and extra renal routes of HCO3− excretion. There was a significant increase in total HCO3− excretion during alkalosis and 95% of it was extrarenal. Although the kidneys can increase base excretion during metabolic alkalosis their capacity is limited with the great majority of base excretion occurring across the skin and/or gills.
Binding of gonadotropins (GTH I and GTH II) to coho salmon gonadal membrane preparations
Authors: Yan Liguang , Swanson Penny , Dickhoff Walton W. 
Published: June 2005

AbstractThis study was designed to optimize binding conditions of salmon gonadotropins (GTH I and GTH II) to membrane preparations of salmon gonadal tissues. Coho salmon (Oncorhynchus kisutch) GTH I and GTH II were radioiodinated by lactoperoxidase method. Binding conditions were characterized using membrane preparations from coho salmon postovulatory ovaries. The optimal conditions for specific binding were the following: pH 7.5, 20–40 mM MgCl2, 15°C, ⩾ 24 hr incubation time. Specific binding of 125I‐GTH I or 125I‐GTH II can be displaced by (in order of relative potency from high to low) GTH I, GTH II, GTH I β‐subunit, and GTH II β‐subunit. GTH α‐subunit did not displace labeled GTHs, but the mixture of α‐ and β‐subunits. GTH but the mixture of α‐ and β‐subunits was more potent than the β‐subunits alone, indicating that recombination of subunits probably occurred. In membranes of postovulatory ovaries, the affinity of the receptor(s) for GTH I was higher, Kd = 0.87 ± 0.12 nM (mean ± SEM), than that for GTH II, Kd = 2.76 ± 0.33 nM; but the receptor density (capacity) was lower for GTH I (31.02 ± 3.72 fmol/mg protein) than that for GTH II (47.01 ± 4.77 fmol/mg protein). Specific binding for both GTH I and GTH II was also detected in membranes of ovaries and testes of immature coho salmon. These resuls suggest the presence of some shared and some separate binding sites for the two gonadotropins.
Expression of an antigen specific for trunk lateral cells in quarter embryos of the ascidian, Halocynthia roretzi
Authors: Nishikata Takahito , Satoh Noriyuki 
Published: June 2005

AbstractCell‐lineage analysis has demonstrated that a pair of the right and left A7.6 cells of a 64‐cell embryo of the ascidian Halocynthia roretzi, descendants of A4.1 cells of an 8‐cell embryo, give rise to trunk lateral cells (TLCs). In this study, in order to investigate cellular mechanisms involved in the specification of TLCs, we have examined the expression of a TLC‐specific antigen in cleavage‐arrested embryos and in quarter partial embryos. Although cleavage arrest of embryos by treatment with cytochalasin B at early stages, prior to and including the 16‐cell stage, inhibited expression of the TLC‐specific antigen, embryos arrested at the 32‐cell stage and at later stages developed the antigen. The only blastomeres exhibiting expression of the antigen were the presumptive TLCs, as predicted by cell‐lineage assignments. When the developmental potential of quarter embryos that originated from four isolated blastomere‐pairs (a4.2, b4.2, A4.1, and B4.1 pairs) of an 8‐cell embryo was examined, the A4.1 quarter embryos, which are developmentally fated to give rise to TLCs, rarely showed evidence of expression of the antigen. Expression of the antigen was not observed in a4.2 and b4.2 quarter embryos, which are not associated with the TLC fate. By contract, expression of the antigen was detected in about a half of the B4.1 quarter embryos which are also not associated with the TLC fate. These results are discussed with reference to the relationship between TLCs and mesenchyme cells.
Inositol 1,4,5‐trisphosphate signals the motile response of fish chromatophores—I. Aggregation of pigment in the tilapia melanophore
Authors: Fujii Ryozo , Wakatabi Hoshitsugu , Oshima Noriko 
Published: June 2005

AbstractAfter permeabilization of the cell membrance by the treatment with a surfactant, Brij 58, inositol 1,4,5‐trisphosphate (IP3) was found to be effective in causing aggregation of melanosomes within melanophores in primary cultures of the tilapia, Oreochromis niloticus. Inositol 1‐monophosphate (IP) and 1,4‐bisphosphate (IP2) did not have such an effect. Phentolamine, an alpha‐adrenolytic agent, and prazosin, a more specific alpha1‐blocker, did not interfere with the action of IP3, even though they were effective in antagonizing the aggregation of pigment in response to norepinephrine. It appears, therefore, that IP3 may function as an intracellular physiological mediator in the signal transduction of pigment‐aggregating stimuli, including at least alpha1‐adrenergic stimuli, possibly via the release of Ca2+ from the intracellular compartments in which they are stored.
Comparative survey of blood thyroxine binding proteins in turtles
Authors: Licht Paul , Denver Robert J. , Herrera Brenda E. 
Published: June 2005

AbstractThe nature of plasma thyroxine (T4) binding activity was surveyed in turtles; binding to [125I]T4 was measured on polyacrylamide gel electrophoresis—PAGE—and on minicolumns of Sephadex G‐25. An electrophoretically distinct T4 binding protein was identified in all 8 species of Pseudemys studied and in 3 other genera (Chrysemys, Deirochelys, and Emyoidea) of the same family, Emydidae. Levels of this binding activity were highly variable among individuals, but they consistently showed a similar low relative mobility (Rf) compared to albumin, and a relatively low capacity was indicated by displacement with unlabeled T4. Two emydids (Terrapene, Clemmys) showed a similar slow migrating binding peak, but binding activity was low and not as easily displaced by unlabeled T4. T4 binding to albumins was minimal in most of these emydid species, even when binding to the higher affinity, low capacity component was low or displaced by unlabeled T4 (2.5 μg/ml). In contrast, there was no clear evidence for a similar high affinity, low capacity binding protein in any of the other 19 species representing 13 genera of 8 families from two suborders. In these species, binding activity on Sephadex G‐25 was typically low and binding on PAGE was associated largely with albumin; binding levels for albumins were highly variable. In several nonemydids (from distant lineages), binding activity on Sephadex was elevated and PAGE showed a second binding protein distinct from albumin, but it had high capacity (not readily saturable). Thus, an evolutionary divergence in T4 transport proteins is suggested within Chelonia.
Importance of intromission in maintaining the alternating pattern of male mounting behavior and hemipenis use in the lizard Anolis sagrei
Authors: Tokarz Richard R. , Kirkpatrick Sean J. 
Published: June 2005

AbstractPrevious studies of the lizard Anolis sagrei have shown that males in a series of copulations exhibit a significant alternating pattern of mounting behavior and hemipenis use and that this behavior may be adaptive by increasing sperm transfer. To investigate the role sensory feedback from the hemipenis may play in maintaining this alternation of mounting behavior and hemipenis use, the effects of preventing intromission, interrupting copulation, and controlling which hemipenis is used were examined. Males that were allowed to mount, but not to intromit in the first of two successive matings, or bilaterally hemipenectomized males that were allowed to complete four matings, did not exhibit significant alternation of mounting behavior. Significant alternation of hemipenis use was exhibited by males that were allowed to intromit but were interrupted in copulation immediately after intromission. Males that were allowed to intromit but were forced in the first of two copulations to use either the left hemipenis, the right hemipenis, or the hemipenis that was used in an earlier copulation did not exhibit significant alternation of hemipenis use. These results suggest that the alternation of male mounting behavior and hemipenis use observed in A. sagrei is dependent on a hemipenis being intromitted and which hemipenis is used, but is independent of copulation duration.
Estrogen‐independent growth of mouse vaginal epithelium in organ culture
Authors: Tsai Pei‐San , Bern Howard A. 
Published: June 2005

AbstractA serum‐free vaginal explant culture system was established to investigate the in vitro effect of estrogen on the growth of mouse vaginal epithelium. Vaginal explants were isolated from 40‐day‐old, ovariectomized BALB/cCrgl mice and cultured in a basal unsupplemented medium or in basal medium plus various doses of 17β‐estradiol. Explants were processed for histology at the end of culture periods or were given 4‐hour pulses of tritiated thymidine at various times and processed for autoradiography. Vaginal epithelium increased 3‐ to 5‐fold in thickness and 2‐fold in the number of epithelial cell layers during 72 hours of culture without estrogen; addition of estrogen did not significantly influence epithelial growth. Keratinization of vaginal epithelium occurred within 48 hours of culture in the absence of estrogen, and again addition of estrogen did not accelerate its appearance. Covering the explants with collagen decreased the estrogen‐independent growth of vaginal epithelium. Autoradiography showed that ca. 70–90% of basal epithelial cells entered S phase during the initial 4 hours of culture and that this number declined rapidly after 48 hours to ca. 20%. Addition of 1.8 nM 17β‐estradiol significantly decreased the labelling index of basal cells at 48 hours, but did not affect the labelling index at 24 and 72 hours. Stromal cells were not labelled at any time. Thus, DNA synthesis, cellular proliferation, and differentiation (keratinization) of vaginal epithelium in organ culture occurred without estrogen and were not stimulated by the addition of estrogen.
Comparative aspects of spermatogenic cell metabolism and Sertoli cell function in Xenopus laevis and mammals
Authors: Risley Michael S. , Morse‐Gaudio Michèle 
Published: June 2005

AbstractDue to the relative dearth of data regarding somatic cell‐germ cell interactions in the testes of non‐mammalian chordates, functional homologies between Sertoli cells from diverse organisms have been difficult to assess. However, recent developments in non‐mammalian testis cell and organ culture techniques have provided experimental approaches to compare Sertoli cell‐germ cell interactions in different vertebrates. Data from in vitro analyses of Sertoli cell‐germ cell interactions are presented to suggest that Sertoli cells from rodents and the frog Xenopus laevis have similarities in supporting energy metabolism and glutathione metabolism in spermatogenic cells. Comparative in vitro analyses of Sertoli cell functions should provide further insights into the evolution of cell‐cell interactions in the testes.
Aspects of the embryology and neural development of the American lobster
Authors: Beltz Barbara S. , Helluy Simone M. , Ruchhoeft Maureen L. , Gammill Laura S. 
Published: June 2005

AbstractIt is feasible to study the anatomical, physiological, and biochemical properties of identifiable neurons in lobster embryos. To exploit fully the advantages of this preparation and to lay the foundation for single‐cell studies, our recent goals have been to 1) establish a quantitative staging system for embryos, 2) document in detail the lobster's embryonic development, 3) determine when uniquely identifiable neurons first acquire their transmitter phenotypes, and 4) identify particular neurons that may serve developmental functions. Behavioral, anatomical, morphometric, and immunocytochemical studies have led to a detailed characterization of the growth and maturation of lobster embryos and to the adoption of a percent‐ staging system based upon the eye index of Perkins (Fish. Bull., 70:95–99, 1972). It is clear from these studies that the lobster nauplius molts at approximately 12% embryonic development (E12%) into a metanauplius, which subsequently undergoes a complete molt cycle within the egg. This molt cycle climaxes with the emergence of the first‐stage larva shortly after hatching.Serotonin and proctolin, neurohormones widely distributed in the lobster nervous system, appear at different times in development. Serotonin immunoreactive neurons begin to appear at approximately E10%, with the adult complement being established by E50%. In contrast, proctolin immunoreactive neurons appear later and attain their full complement over a protracted period including larval and juvenile stages. The development of serotonergic deutocerebral neurons and their targets, the olfactory and accessory lobes in the brain, are also examined. The olfactory lobes are forming by E10% and have acquired their glomerulur organization by E50%, whereas the formation of the accessory lobes is delayed; the early rudiments of the accessory lobes are seen by E50%, and glomeruli do not form until the second larval stage.
Cardiac performance of an isolated eel heart: Effects of hypoxia and responses to coronary artery perfusion
Authors: Davie Peter S. , Farrell Anthony P. , Franklin Craig E. 
Published: June 2005

AbstractThe pericardial sac containing the heart was removed from large (2.7–6.3 kg) longfinned eels (Anguilla dieffenbachii). Coronary arteries were cannulated in preparation for perfusion with eel Ringer or red cell suspensions. The hearts were maintained by Ringer perfusion while the performance of the heart was assessed. Responses of the hearts to increases in filling pressure and output pressure were recorded. Maximum cardiac output was 22.3 ± 1.4 ml/min/kg body mass (mean ± 1 SEM; N = 9). The highest cardiac power output was measured at maximum cardiac output and was 3.39 ± 0.32 mW/g ventricle mass (mean ± 1 SEM; N = 9). Eel hearts could sustain output pressures near 80 cm H2O, but cardiac output was reduced and cardiac power output was 1.89 ± 0.24 mW/g ventricular mass (mean ± 1 SEM; N = 9). Maximum cardiac output decreased by 14% when hearts pumped hypoxic Ringer with a PO2 of 11.5 torr. At high input pressures concomitant with high output pressures (80 cm H2O), cardiac power output decreased by 38% upon exposure to hypoxic Ringer. Coronary perfusion of hypoxic hearts with red cell suspensions (mean hematocrit 10.4%) at a rate of 2% of control cardiac output (0.20 ml/min/kg body mass) had no effect on maximum cardiac output. However, coronary perfusion enabled hypoxic hearts to maintain cardiac output when output pressure was raised to 80 cm H2O. Under conditions of high input pressure and high output pressure, power output increased by 20% compared to hypoxic hearts without coronary perfusion. The role of the coronary supply to eel myocardium is discussed in the light of the differences in power output responses of the coronary perfused hypoxic heart to challenges with high filling pressures compared to high‐output pressure challenges. © 1992 Wiley‐Liss, Inc.
In vitro synthesis of oviductal secretory proteins by estrogen‐treated ovariectomized gilts
Authors: Buhi W. C. , Ashworth C. J. , Bazer F. W. , Alvarez I. M. 
Published: June 2005

AbstractThe objective of this study was to identify, characterize, and examine oviductal secretory proteins (OSP) synthesized de novo by whole oviduct (WO), ampulla (A), and isthmic (I) tissue from ovariectomized (OVX), corn oil (CO)‐, estrogen (E)‐, progesterone (P)‐, and E + P‐treated gilts. Oviducts were collected from OVX gilts after CO, E, P, or E + P treatment for 11 consecutive days and tissue was incubated with 3H‐leucine (3H‐leu). Rates of 3H‐leu incorporation into nondialyzable macromolecules by WO explants were greater (P < 0.01) with E‐ compared to CO‐, P‐, or E + P‐treated gilts and greater (P < 0.05) by A explants with E‐ compared to CO‐, P‐, or E + P‐treated gilts. An effect of location was noted, with A having a greater (P < 0.01) rate of incorporation than WO or I. Conditioned culture medium was analyzed by one (1D)‐ and two‐dimensional (2D) sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) and fluorography. Analyses by 1D‐SDS‐PAGE revealed three major E‐dependent bands (335,000, 100,000, and 80,000 Mr) in WO and A, and one (335,000 Mr) in the I. A 20,000 Mr band found in A was inhibited by E, while a 60,000 Mr band found in the A was induced by P. Analyses by 2D‐SDS‐PAGE resolved major E‐dependent bands 2 (100,000 Mr) and 3 (80,000 Mr) into basic and acidic 100,000 Mr proteins and a 75,000–85,000 Mr protein (pI < 4), respectively, found in WO and A, but not in I. A basic 20,000 Mr protein and an acidic 45,000 Mr complex, both found in A, were inhibited by E. Gel filtration of culture medium revealed a high Mr fraction (> 2 × 106) that was induced by E and was 6.8‐fold greater in medium from A than from I. This study clearly demonstrates that 1) WO and A tissue from E‐treated gilts de novo synthesize and secrete three major proteins (basic 100,000, acidic 100,000, and 75,000–85,000 Mr); 2) these E‐dependent proteins are not found in I or with other treatment; 3) several protein complexes synthesized by A are inhibited by E treatment; and 4) a high Mr fraction, produced primarily in the A, is induced or amplified by E. © 1992 Wiley‐Liss, Inc.
The mechanism of antler casting in the fallow deer
Authors: Goss Richard J. , Van Praagh Andrew , Brewer Peter 
Published: June 2005

AbstractThe process by which antlers are detached from their pedicles was examined histologically in fallow deer castrated in the autumn to induce precocious casting. Osteoclastic erosion across an abscission line between the dead bone of the antler and the living bone of the pedicle was found to be responsible for the separation of the 2. As early as 3 days after castration, osteoclasts and associated lacunae were present on the sides of the pedicle bone. These were then found in progressively deeper locations, by 2 weeks extending across the entire width of the pedicle. Concomitant with the centripetal spread of osteoclasts was the enlargement of Haversian canals, the surfaces of which became lined with osteoclasts. These widening vascular channels within the bone were filled with connective tissue, which in precasting stages formed a mesodermal pad about 1 mm thick. In later stages, a circumferential cleft was excavated beneath the antler burr, and connective tissues from the surrounding pedicle skin invaded the space between the antler and pedicle. After casting, the ingrowing integumental tissues fused with the mesodermal tissues derived from the vascular channels of the pedicle to give rise to an incipient antler bud beneath the scab. The ingrowth of epidermis capable of de novo hair follicle formation gave rise to the future velvet skin that envelops the elongating antler. © 1992 Wiley‐Liss, Inc.
Is the anterior‐posterior axis of the fetus specified before implantation in the mouse?
Authors: Gardner R. L. , Meredith M. R. , Altman D. G. 
Published: June 2005

AbstractThe mouse conceptus is generally held to be radially symmetrical about its embryonicabembryonic axis from the blastocyst stage until the primitive streak appears at the beginning of gastrulation. However, this notion has been challenged by recent observations on conceptuses sectioned in utero which suggest that the blastocyst is already bilaterally symmetrical when it begins to implant. Accordingly, the blastocyst has been assigned an anterior‐posterior axis which appears to persist through gastrulation and is claimed to coincide with the anterior‐posterior axis of the future fetus in both orientation and polarity.In the present investigation the relationship between these two axes was examined in conceptuses dissected from the uterus early in gastrulation so that it could be determined more accurately than is possible in situ. The anterior‐posterior axis of the conceptus and nascent fetus were found to be either parallel or antiparallel to each other, suggesting that while the orientation of the fetal axis may be specified at the blastocyst stage its polarity is not. © 1992 Wiley‐Liss, Inc.
Purification and characterization of m‐calpain from the skeletal muscle of the amphibian Rana ridibunda
Authors: Sargianos N. , Gaitanaki C. , Beis I. 
Published: June 2005

AbstractCalpain was purified to apparent homogeneity from the skeletal muscle of the amphibian Rana ridibunda. It is composed of two subunits of 78 and 28 kDa, respectively.The enzyme exhibits kinetic properties similar to those of mammalian and avian skeletal muscle m‐calpains. Ca2+ requirements for half and maximum activities are 400 μM and 1.5 mM, respectively. It is strongly inhibited by thiol protease inhibitors such as leupeptin, E‐64, and antipain and by alkylating thiol group agents such as iodoacetic acid (IAA), iodoacetamide (IAM), and N‐ethylmaleimide (NEM). Its activity is enhanced by reduced thiols such as dithiothreitol (DTT), cysteine, and 2‐mercaptoethanol. The enzyme is stable in the absence of Ca2+ at 55°C, it displays maximum activity at 25°C, and it shows a broad pH optimum between 6.5 and 7.8. In the absence of Ca2+, various divalent cations such as Sr2+, Mn2+, and Ba2+ strongly activate, while other divalent cations such as Ni2+, Co2+, Cd2+, Zn2+, and Cu2+ have no effect on its activity. In the presence of Ca2+, the cations Sr2+, Mn2+, and Ba2+ show a synergistic effect, while the cations of the other group strongly inhibit the calpain activity. The above data demonstrate that calpain from the skeletal muscle of the amphibian Rana ridibunda is a neutral, Ca2+‐activated thiol protease and that it belongs to the class of m‐calpains. © 1994 Wiley‐Liss, Inc.