bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of digit regeneration and their implications for theories of development and evolution of vertebrate limbs
Authors: Stock Gregory B. , Bryant Susan V. 
Published: June 2005

AbstractSimple amputation of various combinations of hindlimb digits of Notophthalmus viridescens resulted in a variety of abnormal regenerates. The abnormalities included the formation of adventitious digits and branched digits, fusion between digits, and increases and decreases in the normal number of phalanges. The type of abnormality was correlated with the proximal‐distal level of amputation and with the identity of the digits removed. These results are discussed in the context of a model for normal digit formation. An important feature of this model is that the normal regeneration of separate digits is dependent upon precise and orderly interactions between different parts of the limb circumference. In the experiments we report, the disruption of these orderly interactions leads to a variety of abnormalities. In addition, the model for digit formation presented here is discussed in light of its implications for evolutionary trends in the tetrapod limb.
Changes in concentrations of taurine in murine harderian glands and retinas during postnatal development
Authors: Hilton Frederick K. , Raque George H. , Hilton Mary A. 
Published: June 2005

AbstractQuantative measurements of taurine in the Harderian glands of male and female CF‐1 mice were made by standard methods of amino acid analysis. Values, in nmoles per mg dry weight of gland, were 60 to 70 in the first 4 postnatal days with a gradual decrease to 31.1 ± 3.5 at 12 days, just prior to eye opening. This was similar to the value of 27 ± 1 observed in sexually mature males, 53 days old. Two to 11 animals were used to establish each value. Other free amino acids in the glands are present in much lower concentrations, difficult to quantitate. Comparisons of the nmolar concentrations of taurine in dry retinas and Harderian glands from the same animals revealed two to three fold higher concentrations in the retina until the time of eye opening, after which concentrations increased markedly to greater than 160 nmoles per mg dry retina at 16 days and older.
Substitution of a synthetic polymer for protein in a mammalian gamete culture system
Authors: Bavister Barry D. 
Published: June 2005

AbstractPolyvinylalcohol (PVA) was tested as a replacement for protein (bovine serum albumin, BSA) in supporting motility, acrosome reactions, and fertilizing ability of hamster spermatozoa in vitro. Bovine serum albumin is normally required for all of these processes. After incubation for 5–6 hours in a simple culture medium containing BSA and PVA (0.1 mg/ml) and essential low molecular weight factors from blood serum, 85% of motile spermatozoa had undergone acrosome reactions. Sperm motility was equally well maintained by PVA in the absence of BSA but virtually no spermatozoa showed acrosome reactions even after prolonged incubation. Serum factors were later replaced by hypotaurine (10 μM), isoproterenol (1 μM), and penicillamine (20 μM). Spermatozoa incubated in this defined medium with BSA alone or with BSA and PVA fertilized more than 90% of oocytes. No oocytes were penetrated when BSA was replaced by PVA although vigorous sperm motility was maintained. Polyvinylalcohol may help elucidate the mechanism of the acrosome reaction by permitting effects of protein and other substances to be studied without loss of sperm motility (viability). Polyvinylalcohol could also replace BSA in solutions used for manipulation of zona pellucida‐free oocytes. It is suggested that PVA may find general application in cell culture media.
The mechanism of hatching in Fundulus heteroclitus: Development and physiology
Authors: Dimichele Leonard , Taylor Malcolm H. 
Published: June 2005

AbstractThe development and physiology of the hatching mechanism were examined in Fundulus heteroclitus. Histological examination of the hatching glands revealed that they first became differentiated on or about day 5 of development. By day 7 the glands took on a granular appearance which was correlated with the first appearance of chorionase. From day 7 to day 10, growth of the glands and their increase in chorionase content were exponential. Cell size and chorionase activity peaked on day 10 and thereafter remained constant until hatching. The effects of several drugs were tested for their effects on hatching. Epinephrine and low concentrations of MS‐222, in conjunction with low oxygen concentration, were found to advance the median hatching date of eggs (HD50). Turbocurarine, high concentrations of MS‐222, and atropine inhibited hatching completely, as did transection of the hind brain. On the basis of these experiments we have hypothesized that a respiratory stress response is linked to chorionase release during normal hatching.
Effect of purified zona antibody on fertilization in the mouse
Authors: Tsunoda Y. , Sugie T. , Mori J. , Isojima S. , Koyama K. 
Published: June 2005

AbstractBivalent (IgG) rabbit anti‐mouse zona pellucida antibody completely inhibited fertilization in the mouse. Univalent (Fab) zona antibody did not inhibit the fertilizability of eggs. However, the treatment or injection with anti‐rabbit IgG serum inhibited the fertilizability of eggs pretreated with antiserum Fab or eggs from females injected with antiserum Fab. It is concluded that the inhibition of fertilization by bivalent mouse zona antibody depends on the possibility that the antisera are directed against the zona as a whole and not specifically against the receptors for the Sperm.
Purification and properties of cytoplasmic malate dehydrogenase isolated from a larval crustacean, Artemia salina
Authors: Hand Steven C. , Becker Mary M. , Conte Frank P. 
Published: June 2005

AbstractThe cytoplasmic isozyme of malate dehydrogenase (s‐MDH) has been isolated from brine shrimp nauplii to a state of high purity. The purified enzyme is free of glutamate‐oxaloacetate transaminase and lactate dehydrogenase activities and has specific activities of 550–570 μM NAD+/min/mg protein (oxaloacetate reduction) or 115 μM NADH/min/mg protein (malate oxidation). Nondenaturing polyacrylamide gel electrophoresis resolved at least three catalytically active s‐MDH subforms with no observable non‐MDH protein present. The enzyme displays a single uniform boundary in sedimentation velocity centrifugation which yields a S20,w value of 4.4. From sedimentation equilibrium a molecular weight of 75,300 is calculated, and a break in the plot of In C versus r2 is evident for the low protein concentration portion of the boundary, suggesting a dimer–monomer dissociation and/or a low molecular weight microcontaminant. Sodium dodecyl sulfate polyacrylamide gels give an apparent molecular weight of 36,000–38,000 for the s‐MDH subunit. The cytoplasmic isozyme has a pH optimum of 8.0 for oxaloacetate reduction and exhibits low susceptibility to thermal denaturation, with less than 10% loss of catalytic activity observed at 48°C in 1 hour. An Arrhenius plot gives a linear relationship with no transitions and an estimated molar activation energy of 9.75 Kcal/mole for the overall catalytic step. Michaelis constants in 0.05 M Tris/HCL buffer, pH 8.0, at 25°C are 4.2 × 10−5 M for oxaloacetate and 1.5 × 10−5 M for NADH, and the molecular activity (kcat) is 42,000. Substrate inhibition by oxaloacetate or malate is not observed at low concentrations, but begins at 7–10 mM and 20–30 mM, respectively.
Elimination of the interstitial cells in the planula larva of the marine hydrozoan Pennaria tiarella
Authors: Martin Vicki Joan , Thomas Mary Beth 
Published: June 2005

AbstractTreatment of 8‐hour embryos of the marine hydrozoan Pennaria tiarella with colchicine results in the complete elimination of interstitial cells, nematoblasts, and sensory‐motor‐interneurons. Depletion of these cells is mediated through the action of acid phosphatase‐positive autophagic vacuoles.Larvae depleted of interstitial cells acquire normal polarity although body form is somewhat modified. This modification appears to be due to a loss in cell volume normally provided by the interstitial cells. These larvae remain without interstitial cells throughout larval life. This finding demonstrates that the remaining larval epithelial cells are not totipotent and therefore lack the plasticity to redifferentiate into interstitial cells. The fact that epitheliomuscle cells, mucous cells, neurosensory cells, and gastrodermal cells all differentiate normally after elimination of the interstitial cells suggests that the interstitial cells are not involved in induction of the epithelial cell types. Furthermore, the histological organization of the presumptive epithelial cells appears in no way to be affected by the interstitial cells. In the absence of these cells the remaining cells of the embryo become organized into a distinct epidermis and gastrodermis separated by a mesoglea. Larvae devoid of interstitial cells and their derivatives fail to metamorphose.The specific mechanism by which colchicine eliminates the interstitial cells is investigated. Embryos treated with vinblastine sulfate and podophyllotoxin, both known microtubule inhibitors, exhibit the same autophagic elimination of the interstitial cells, the nematoblasts, and the sensory‐motor‐interneurons as that seen in embryos treated with colchicine. Embryos treated with lumicolchicine are identical morphologically to control planulae of comparable age and contain interstitial cells, nematoblasts, and sensory‐motor‐interneurons. These results demonstrate that the principle action of colchicine in Pennaria is microtubule related.
Long‐term effects of hypothalamic lesions on the pituitary and its target organs in the killifish Fundulus heteroclitus. I. Effects on the gonads, thyroid, and growth
Authors: Pickford Grace E. , Knight W. Rea , Knight Janet N. , Gallardo Roberto , Baker Bridget I. 
Published: June 2005

AbstractIn three experiments a total of 23 sham‐operated and 63 brain‐lesioned killifish were maintained for 12½–16½ weeks under constant environmental conditions, with regular feeding. Regression of the testes and pituitary gonadotropes, seen in 13 fish, was correlated with lesions in the parvocellular region and/or tract of the nucleus lateral tuberis pars anterior (NLTa). Marked hypertrophy of the thyroid and pituitary thyrotropes, seen in nine fish, was associated with severe lesions of the nucleus anterior tuberis (NAT). A highly significant increase in growth rate, seen in four fish, was correlated with lesions in the nucleus preopticus (NPO), but there was no change in the pituitary somatotropes. Increased appetite, resulting from the presumed destruction of a satiety center, is a possible explanation.
Pattern formation following 180° rotation of regeneration blastemas in the axolotl, Ambystoma mexicanum
Authors: Tank Patrick W. 
Published: June 2005

AbstractForelimbs of larval axolotls were amputated through the distal one‐third of the humerus. The resulting palette stage regeneration blastemas were rotated 180° and replaced on the original limb stump. This surgery offset both the anteroposterior and dorsoventral axes of graft and stump. Supernumerary limbs formed at anterior and posterior regions in the graft–host junction. Most supernumerary limbs displayed variable degrees of fusion with the graft. In these fused limbs the half of the supernumeray limb that was adjacent to the graft developed with the palm dorsally (in harmony with the graft), whereas the half of the supernumerary limb that was adjacent to the stump developed with the palm ventrally (in harmony with the stump). Anterior supernumerary limbs that were clearly separated from the graft were of stump handedness. Posterior supernumerary limbs that were clearly separated from the graft were of handedness opposite to the stump. Two types of derotation phenomena are described. These results are discussed in view of several recent theories for pattern regulation in epimorphic fields.
The effect of calcium on the first meiotic division of the mammalian oocyte
Authors: Paleos George A. , Powers R. Douglas 
Published: June 2005

AbstractIn the mammalian ovary, fully grown oocytes are arrested at the diplotene stage of the first meiotic division. While oocytes in vivo resume meiosis only in response to a preovulatory surge of gonadotropic hormones, oocytes isolated from the ovaries and cultured in vitro will spontaneously resume meiosis. Both in vivo and in vitro, meiotic maturation proceeds through the extrusion of the first polar body, where it is again arrested until fertilization. We have used the spontaneous, in vitro maturation of the mouse oocyte to examine the role of calcium in germinal vesicle breakdown (GVBD) and polar body extrusion. In calcium‐free medium or in the presence of concentrations of lanthanum greater than 0.5 mM, the oocytes degenerate rapidly. However, there does not appear to be any effect upon maturation that can be distinguished from a general toxicity of these media. In contrast, two treatments that are known to inhibit transmembrane calcium movements, verapamil and tetracaine each, individually, inhibit polar body formation. They have no effect on GVBD. In addition, oocytes cultured in media containing a higher calcium concentration than control media (greater than 10 mM versus 1.71 mM) show a significantly higher percentage of polar body formation. We conclude that, in these culture conditions, extracellular calcium is not required for GVBD but is required for the completion of the first meiotic division of a mammalian oocyte.
Rat serum promotes the in vitro development of mouse blastocysts during early somitic stages of embryogenesis
Authors: Wu Tsung‐Chieh , Wan Yu‐Jui , Damjanov Ivan 
Published: June 2005

AbstractMouse blastocysts cultured in vitro in rat serum develop through the early somitic stages of embryogenesis at the same rate as embryos cultured in human cord serum. Rat serum can thus be used instead of human cord serum for in vitro culturing of mouse embryos.
Oxygen and carbon dioxide exchange during exercise in the land crab (Cardisoma carnifex)
Authors: Wood Chris M. , Randall D. J. 
Published: June 2005

AbstractIn Cardisoma carnifex exercised on a treadmill, there is an inverse relationship between velocity and log fatigue time; crabs run indefinitely at 0.2 body lengths/second, for ≃5 minutes at 0.5 BL/second, and for only ≃30 seconds at burst speeds of 2.2 BL/second. Respiration was studied at rest and after 10 minutes of either mild (0.2 BL/second) or severe (exhausting, 0.5 BL/second) exercise. Gas exchange occurs in large branchial chambers that contain gills and are lined with a respiratory epithelium. The chambers are partially filled with water, and are ventilated with air by forward scaphognathite pumping. Motions of the flabellae, gills, and branchial chamber wall mix the air and water phases. CO2, but not O2, equilibrates between the phases, so the water represents a significant CO2 sink. At rest, the scaphognathites beat in short, often unilateral bursts, and air flow is intermittent. O2 utilization is > 11.4%, the ventilatory convection requirement is ≃1.3 L air/mMole O2, the gas exchange ratio (R) is ≃0.6, the O2 diffusing capacity is ≃0.4 μmole O2. kg−1 min−1. torr−1, or about 10% of the CO2 diffusing capacity, and Po2 and P gradients across the respiratory surface are comparable to those in air‐breathing ectothermic vertebrates. During exercise, scaphognathite activity becomes bilateral and continuous, ventilation rises, utilization falls, and gas tensions in the branchial chamber approach those in the inspired air. Heart rate rises slightly. Ṁ and Ṁ increase 2–5 ×, the latter to a greater extent, and a considerable O2 debt is incurred. R rises above 1.0 as metabolic acidosis converts bicarbonate stores to CO2. The increases in Ṁ and Ṁ reflect both elevations of the diffusion gradients and approximate doublings of the O2 and CO2 diffusing capacities. All changes are more marked during severe than during mild exercise, but the patterns are similar.
Carbon dioxide excretion in the land crab (Cardisoma carnifex)
Authors: Randall D. J. , Wood Chris M. 
Published: June 2005

AbstractThe hemolymph of Cardisoma carnifex shows a small Haldane effect and some CO2 is probably bound to blood proteins. Carbonic anhydrase activity is located in the gill epithelium but is absent from the blood. Inhibition of carbonic anhydrase activity in vivo by injection of 50 mg/kg Diamox into the infrabranchial sinus causes a prolonged increase in blood P and the P gradient across the gills. Both M and M, however, are maintained at normal rates during rest and severe exercise. The gill diffusing capacity for CO2 is reduced by Diamox treatment, and it is concluded that the catalysed bicarbonate dehydration reaction within the gill epithelium contributes to the pool of excreted CO2. During exercise the CO2 content of the blood is decreased, and bicarbonate is probably mobilized from other sources in the body. It is possible that Diamox interferes with this process.
Acid‐base balance following temperature acclimation in land crabs
Authors: McMahon B. R. , Burggren W. W. 
Published: June 2005

AbstractAcid‐base responses to change in body temperature have been described for terrestrial ectothermic vertebrates, but not for terrestrial invertebrates. The present study described changes in pH, carbon dioxide contents (C), and partial pressures (P) in prebranchial hemolymph of three supralittoral crustaceans acclimated 5 days to three temperatures.The anomuran Coenobita brevimanus, a land hermit crab, and the brachyuran Cardiosoma carnifex, were acclimated to 25°, 15°, 25°, 35°, 25° in that order. Exposure to 15° caused extreme torpidy in these species, and thus Birgus latro were exposed to 25–35–25–20° temperature steps.All animals tested showed ΔpH/Δt relationships similar to those of other ectotherms (Birgus 0.023, Coenobita 0.017, Cardisoma 0.017 pH units, °C). The manner of acid‐base status regulation, however, varied between species. Birgus allowed P levels to rise and maintained a constant C level as temperature rose, as do many terrestrial ectothermic vertebrates. Cardisoma showed a rise in P without significant change in C only between 25°C and 35°C. At 15°C no significant fall in P occurred, whereas C increased significantly, a situation similar to that seen in many aquatic ectotherms. Coenobita also showed responses intermediate between those typical of air‐breathing and water‐breathing ectotherms. These data suggest that while Birgus, reputedly the most “terrestrial” of the three species studied, apparently controls acid‐base status in a manner similar to that of most terrestrial ectothermic vertebrates, both Coenobita, which has water available in the shell, and Cardisoma, which has water available in the burrow, can also utilize mechanisms typical of aquatic ectotherms. Possibly these latter animals are bimodal breathers and can switch from one mechanism of acid‐base regulation to the other depending on the availability of water and other physiological needs.
Hemolymph oxygen transport, acid‐base status, and hydromineral regulation during dehydration in three terrestrial crabs, Cardisoma, Birgus, and Coenobita
Authors: Burggren Warren W. , McMahon Brian R. 
Published: June 2005

AbstractHemolymph oxygen transport, acid‐base status, and hydromineral regulation have been measured at 28–30°C in Cardisoma carnifex, Birgus latro, and Coenobita brevimanus in their normal hydrated state, following a period of severe dehydration, and after a subsequent 24‐hour period of rehydration.Cardisoma and Birgus tolerated a maximum loss of body water of 20%, which developed in 3–4 days without water, and resulted in an 25–30% increase in hemolymph osmolality. Ion concentrations also increased considerably, with the largest percentage increases in ion concentration occurring for Mg++, Ca++, and K+.A metabolic acidosis and a resultant fall in HCO developed in Cardisoma and Birgus, but PCO2 showed no large changes, suggesting little respiratory compensation. Oxygenation of postbranchial hemolymph was not affected during dehydration, since P and hemolymph O2 capacity increased, the latter because of a hemoconcentration. Within 24 hours of rehydration, a restoration of the original levels of hemolymph ions and osmolality occurred, and a nearly complete return to normal acid‐base status developed.Coenobita was distinctive, since dehydration to the maximum tolerated 28% loss of body water appeared to be accompanied by a closer regulation of hemolymph ion levels. Only protein increased, which probably accounted for some of the rise in hemolymph osmolality. However, hemolymph O2 capacity fell, and that, in conjunction with a significant reduction in P, suggested a more severe disruption of O2 transport than in either Cardisoma or Birgus. The metabolic acidosis and the fall in HCO during dehydration were also more profound, and Coenobita showed the least recovery of these three species after 24 hours of rehydration.
Acid‐base responses to changes in CO2 in two pacific crabs: The coconut crab, Birgus latro, and a mangrove crab, Cardisoma carnifex
Authors: Cameron James N. 
Published: June 2005

AbstractThe blood pH was depressed in the terrestrial coconut crab, Birgus latro, by about 0.3 units when the animals were forced to breathe 3% CO2 in air. This hypercapnic acidosis was compensated over 24 hours by a 15.4 mM · L−1 increase in blood bicarbonate, but little amelioration of the pH depression was achieved (less than 0.15 units). The increased base excess could not arise from ion exchange with water, and did not apparently involve antennal gland excretion either. The distribution of injected DMO changed in a way that indicated that the intracellular compartment was supplying about half of the observed base excess. In an amphibious, or bimodally breathing crab, Cardisoma carnifex, a reduction of the normal blood P by forced water breathing led to an opposite hypocapnic alkalosis, the blood P dropping from 10.6 to 7.0 torr. This led to a progressive metabolic acidosis, which maintained the blood pH within 0.1 unit of control (air‐breathing) values. The distribution of injected DMO in C. carnifex did not indicate any participation of the intracellular bicarbonate pool in the adjustment to the hypocapnia. It appears that only in the fully terrestrial crabs, deprived of an aquatic medium enabling ionic exchange processes, are other mechanisms for acid‐base regulation brought into play.
Salt and water balance and antennal gland function in three pacific species of terrestrial crab (Gecarcoidea lalandii, Cardisoma carnifex, Birgus latro). I. Urine production and salt exchanges in hydrated crabs
Authors: Kormanik Gregg A. , Harris R. R. 
Published: June 2005

AbstractRates of inulin clearance and urine production were determined in Gecarcoidea lalandii on full‐strength seawater‐moist sand, in Cardisoma carnifex on 800 mOsm seawater‐moist sand; and in Birgus latro with access to distilled water for drinking. Urine production in G. lalandii was 3.4 ± 0.6 ml·100 g−1·d−1, and the inulin U/B ratio was 0.77 ± 0.01 (n = 6). The urine production rate for C. carnifex was 3.2 ± 0.5 ml·100 g−1·d−1, and the inulin U/B ratio was 0.95 ± 0.01 (n = 6). We were unable to collect urine from B. latro, but the inulin clearance rate was over twice that observed in either G. lalandii or C. carnifex. The inulin U/B ratios we observed were less than unity, which indicated a secretion of fluid into the urine. In general, this secreted solution was slightly hyperosmotic, isoionic with respect to sodium and slightly hyperionic with respect to chloride, but appeared to be of minimal use in salt regulation. Unidirectional sodium fluxes were determined in C. carnifex and B. latro, and compared with the estimated urinary sodium fluxes. The antennal gland appears to be the major site of sodium loss. Under our experimental conditions, the antennal gland was the major site for the loss of salt and water, and it appears to be of minimal use in the retention of salts.