bluuebunny/crossref_metadata_2025 huggingface dataset:
Regeneration of antennae and its control of molting in the terrestrial isopod, Armadillidium vulgare
Authors: Madhavan Kornath , Madhavan Mekkara Mandaravally
Published: June 2005

The interactions of regeneration and pregnancy controls on the duration of different stages of molting in the pillbug Armadillidium vulgare were determined by removing the antennae during different stages of the molt cycle of the nonovigerous and ovigerous animals. Removal of one or two antennae from the males during the beginning of stage C (intermolt period) of their molting cycle resulted in regeneration and shortening of stage C and thereby in acceleration of ecdysis. Further, removal of both antennae induced the animals to ecdyse within 1–4 days of each other, thus providing a convenient method of synchronizing the molt cycle. Amputation of both antennae from males in late stage C also resulted in regeneration; however, the duration of stage C was lengthened, resulting in a delay in ecdysis. Amputation of both antennae from males and nonovigerous females in the middle of preecdysis (stage D) resulted in molting without regeneration and on schedule like the control animals. However, the antennaless animals regenerated their antennae, shortened their intermolt period (stage C), and ecdysed precociously. From these results, we conclude that amputation, before the critical period in the molt cycle of the pillbugs (during stage C), prevents the release of ecdysteroids and, consequently, generalized apolysis until regeneration is completed, whereupon this block is removed and generalized apolysis and further events of molting occur. Once ecdysteroid release has been initiated to cause generalized apolysis, as in stage D, amputation does not prevent the further events of molting. Amputation of both antennae during the beginning of the intermolt period in the ovigerous females, although permitting regeneration, did not immediately stimulate ecdysis as in the nonovigerous animals; instead, it occurred only after release of the larvae from the brood pouch. When compared to the control ovigerous animals, the overall length of stage C was shortened. The results obtained from the antennal amputations during different physiological stages of the pillbug show that of all the stages of the molt cycle, stage C is labile, and its duration is affected by regeneration and pregnancy.
Morphology of neurons containing monoamines within leech segmental ganglia
Authors: Lent Charles M.
Published: June 2005

The monoamine‐containing neurons within leech segmental ganglia are vitally and selectively stained by Neutral Red dye—a procedure facilitating the investigation of their morphology by means of intracellular injections of the tracer enzyme, horseradish peroxidase. The colossal Retzius cells are peripheral effector neurons which project large axons into the lateral roots and smaller axons into the anterior and posterior longitudinal connectives. All classes of the smaller ganglionic neurons which also contain serotonin (VL, DL, M, and E), as well as the catecholamine soma in the anterior root (AR), have extensive arborizations within the neuropile and project their axons only into the longitudinal connectives. Each of the five classes of small amine cell has a highly specific morphology and appears to be an interneuron.
The effect of prolactin on the rate of forelimb regeneration in newts exposed to photoperiod extremes
Authors: Maier C. Eberhardt , Singer Marcus
Published: June 2005

Four groups of bilaterally amputated newts were exposed to (1) continuous light, LL; (2) continuous light with daily prolactin injections, LL‐PRL; (3) total darkness, DD; or (4) total darkness with daily prolactin injections, DDPRL. The results confirmed that LL animals regenerate their limbs more rapidly than DD. The results also showed that LL‐PRL animals do not respond to the exogenous prolactin but that DD‐PRL animals do respond and in fact regenerate at a rate which exceeds not only DD but also LL and LL‐PRL. The possible synergism between prolactin and photoperiod is discussed.
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

Simple 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

Quantative 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

Polyvinylalcohol (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

The 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

Bivalent (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

The 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

Treatment 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

In 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

Forelimbs 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

In 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

Mouse 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

In 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

The 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

Acid‐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

Hemolymph 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

The 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

Rates 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.
Salt and water balance and antennal gland function in three pacific species of terrestrial crab (Gecarcoidea lalandii, Cardisoma carnifex, Birgus latro). II. The effects of desiccation
Authors: Harris R. R. , Kormanik Gregg A.
Published: June 2005

The rates of body water loss and the maximum tolerable losses in the three Indo‐Pacific species of land crab (Gecarcoidea lalandii, Cardisoma carnifex and Birgus latro) were similar to those of other terrestrial decapod crustaceans of marine origin. During dehydration, the haemolymph osmolalities and Na and Cl concentrations increased in all species; and in Gecarcoidea and Cardisoma, corresponding increase in urine concentrations were found. Thus the U/B ratios of all three parameters did not change significantly from those of hydrated animals. As in other crabs, a urine hyperosmotic to the haemolymph was not produced during desiccation.

Clearance of the filtration marker inulin from the haemolymph ceased in these two species, so reduced urine production is suggested to be an important mechanism in limiting water loss. No post‐filtration withdrawal of fluid from the antennal gland, which would be indicated by an increase in inulin U/B ration to in excess of unity, appeared to take place under these conditions.

During desiccation the extracellular solute volume in Gecarcoidea and Cardisoma remained relatively constant, in contrast to Birgus, where a significant decrease in volume, equivalent the volume of body water lost, occurred. This suggests that in Birgus the intracellular volume is conserved. The consequence of this in Birgus the intracellular volume decrease on the measurement of clearance rates is discussed. It is suggested, from indirect evidence, that in Birgus the antennal gland continued to produce urine during desiccation.

The increases in haemolymph solute concentrations, while the extracellular spaces remain unchanged, requires a net movement of solutes into the haemolymph in Gecarcoidea and Cardisoma. In Birgus the increase in haemolymph concentration is less than would be expected if it was inversely proportional to the decrease in extracellular volume, implying some removal of solutes from this compartment.
The energy metabolism of the leech Hirudo medicinalis in anoxia and muscular work
Authors: Zebe E. , Salge U. , Wiemann C. , Wilps H.
Published: June 2005

The medical leech Hirudo medicinalis has only small reserves of glycogen (˜ 40 μmol/g fresh weight), but malate is present in comparatively high concentrations (8 to 10 μmol/gm fresh weight) in the tissues and in the blood. Leeches are able to survive several days of anoxia at 20°C. From the onset of anoxia the level of malate drops rapidly and concomitantly the concentration of succinate rises in converse manner. After the initial phase, both metabolites do not change significantly. Then large quantities of propionate accumulate which, in part, are also excreted into the surrounding water. In contrast, continuous swimming causes the concentration of lactate to rise steeply and lactate is the dominant end product. There is only a modest decrease in the concentration of malate whereas succinate does not change. These distinct patterns of metabolite concentrations arising in anoxia and in muscular activity seem to indicate that different modes of energy metabolism are used in both situations.
An acrosome reaction in natantian sperm
Authors: Clark Wallis H. , Kleve Maurice G. , Yudin Ashley I.
Published: June 2005

Sperm of the natantian Sicyonia ingentis are highly polarized with a conical cap and single spike extending from a spherical main body. The acrosome consists of a spiraled spike and two glycoprotein cap components: the anterior granule and the membrane pouches. During sperm‐egg interaction, the spike is lost and the cap membrane folds back, exposing the two glycoprotein acrosomal components. At this point, the anterior granule lies directly adjacent to the oolemma and has replaced the spike as the anterior end of the sperm. Treatment of sperm with ionophore A23187 initiates the acrosome reaction, thereby facilitating the experimental sequencing of the reaction. The ionophore‐induced reaction begins with the spike's loss of its spiraled nature, the appearance of filaments in the spike core, and the immediate depolymerization of the spike into a granular mass. As the spike retracts, the membrane pouches swell. The cap membrane in the area of the retracted spike ruptures and begins to fold back. As seen during natural sperm‐egg interaction, the anterior granule becomes the new anterior end of the sperm after loss of the spike. Several known artificial activators of sperm were tested, but only the divalent cation ionophore A23187 successfully induced the acrosome reaction. The use of artificial seawater with different ionic properties showed that the acrosome reaction is dependent on the influx of Ca++ ions.
Microsphere studies of amphibian systemic blood flow redistribution during dehydration, hypovolemia, and salt load
Authors: Hillman Stanley S. , Sommerfeldt R. W.
Published: June 2005

Systemic blood flow distribution was monitored in a variety of anuran amphibians using trapping of 54‐μm mean radionuclide‐labeled micro‐spheres during control, dehydration, hypovolemia, and salt load treatments. The head was the only region which showed significant increases in its proportion of systemic blood distribution in both dehydration and hypovolemia relative to controls. Proportionate declines in blood flow were observed to skeletal muscle regions during dehydration and hypovolemia. Salt loading had no effect on blood flow distribution. The redistribution results are consistent with sympathetic reflex control during hypovolemia and dehydration. The magnitude of the cerebral redistribution did not correlate with a species' tolerance to dehydration.
The epidermal melanocyte population in the skin of ultraviolet‐irradiated crested newt
Authors: Losa Massimo , Zavanella Teresa , Milani Silvano
Published: June 2005

The response of the epidermal melanocyte population to repeated ultraviolet (UV) exposure (wavelength spectrum 275–350 nm) has been investigated in the crested newt, Triturus cristatus carnifex. The effects of different doses of UV light were studied. The animals were killed 7 months after the first UV exposure. Only a slight decrease in the number of pigment cells was found after 85 sequential irradiations with a total dose of 1.3 × 105 J/m2, whereas striking decreases were observed when the same total dose was fractionated into 14 exposures or when a double dose was given in 57 exposures. The relationship between the square roots of the epidermal melanocyte densities and single doses appeared to be roughly linear, at least over the range of doses administered. The main factor in melanocyte damage seemed to be the single dose of irradiation rather than the cumulative dose administered. Decreased melanin content of the keratinocytes was observed in most irradiated animals.
The spatial pattern of RNA in fully grown oocytes of an amphibian, Xenopus laevis
Authors: Capco David G.
Published: June 2005

The possibility that maternal RNA may be localized in specific oocyte regions was examined in fully grown oocytes of Xenopus laevis. These oocytes were subdivided into six regions perpendicular to their animal‐vegetal axis. Each region was analyzed to determine the amount of total cellular RNA, poly(A)+RNA, and newly synthesized ribosomal RNA. As would be expected from current evidence, total cellular RNA was found to exist in a gradient‐like fashion, highest at the animal pole and lowest at the vegetal pole. However, poly(A)+RNA and newly synthesized ribosomal RNA had significantly different spatial patterns from each other and from total cellular RNA. In addition, evidence suggests that newly synthesized ribosomal RNA requires two to three days before it is uniformly distributed within the oocyte. These results suggest that a mechanism may exist to create different spatial patterns for different classes of RNA.
The role of the blood in the temperature dependence of oxidative metabolism in decapod crustaceans. I. Intraspecific responses to seasonal differences in temperature
Authors: Mauro Nicholas A. , Mangum Charlotte P.
Published: June 2005

Total oxygen uptake in the blue crab Callinectes sapidus doubles with a rise in ambient temperature in the range 15–25°C, and increases precipitously (Q10=4.92) in the range 5–15°C. Both systemic and cellular phenomena are responsible for the pattern. At summer temperatures, where motor activities are maximal, the oxygen affinity of blue crab hemocyanin is low, and considerable volumes of oxygen are delivered to the tissues. At winter temperatures, where feeding and locomotion virtually cease, the hemocyanin‐oxygen (HcO2) affinity is so high that little oxygen can be extracted by the tissue and O2 is transported entirely in the free form. At the transitional temperature of 15°C, a seasonal acclimation of HcO2 affinity permits appreciable oxygen delivery to the tissues in the spring, but curtails oxygen delivery in the fall.

Both muscle and hepatopancreas utilize the hexose monophosphate shunt (HMS) in carbohydrate metabolism. Specific activities of the enzymes participating in the HMS are greater in hepatopancreas than muscle, and the sensitivity of O2 uptake to the glycolytic inhibitor iodoacetate (10−2 M) is smaller. The temperature dependence of O2 uptake in the range 15–25°C is much smaller in hepatopancreas than in muscle. The ratio of C‐1/C‐6 labeled glucose utilization indicates that, at low temperature, the activity of the HMS in hepatopancreas is five times greater than that of glycolysis. Thus, the low thermal sensitivity of O2 uptake in hepatopancreas appears to be due to a change in the relative contribution of the two pathways to total carbohydrate metabolism.

There is no evidence of a compensatory response of intermediary metabolism in muscle, which comprises the major fraction of total biomass. The thermal dependence of O2 uptake by the animal exceeds that of either hepatopancreas or muscle, due to the large increase in HcO2 affinity, and hence a decrease in tissue O2 supply, at low temperature.
The effect of neurogenic stimulation on the development and growth of bony tissues
Authors: Bubenik G. A. , Bubenik A. B. , Stevens E. D. , Binnington A. G.
Published: June 2005

In order to elucidate the mechanisms of neurogenic control of bone devlopment and growth, the effects of traumatic and electric stimulation on the development, size, and shape of antler bone tissue were investigates. Unilateral growth of antler in a female deer was initiated after traumatic stimulation of the frontal bone. Electrical stimulation of antler nerves or antler periosteum resulted in an increase in more than 70% in antler length and over 40% in weight. Stimulation of antler nerves also resulted in abnormal shape of antlers. The role of periosteal nerves and the participation of the central nervous system in the responses to stimulation is discussed.
Evidence that secondary neurulation occurs autonomously in the chick embryo
Authors: Costanzo Renée , Watterson Ray L. , Schoenwolf Gary C.
Published: June 2005

Other investigations have demonstrated that pressure, exerted by fluid contained within the lumen of the closed neural tube, plays an important role in the morphogenesis of cranial regions of chick embryos. In this study, we investigated whether this pressure is involved also in the formation of the secondary portion of the neural tube‐the portion formed by canalization of a solid mass of cells. To determine this, the posterior neuropore was prevented from closing (resulting in myeloschisis localized to the lumbosacral region) by removing the portion of the vitelline membrane covering the embryo, and reincubating for various periods. Secondary neurulation occurred normally in embryos exhibiting lumbosacral myeloschisis, demonstrating that this process occurs autonomously in chick embryos. Additional experimental studies are needed to ascertain what specific mechanisms cause the secondary portion of the neural tube to form.
RNA synthesis in immature mouse oocyte development
Authors: Fourcroy Jean L.
Published: June 2005

Oocyte development in several nonmammalian species is characterized by the synthesis of large quantities of ribonucleic acids during lampbrush stages of meiosis. These are stored in the oocyte and used during later oocyte maturation and early embryogenesis. This autoradiographic study examined the incorporation and persistence of ribonucleic acid in mouse oocytes during comparable stages of development. At each age examined, fetal through juvenile, the radiolabeled RNA precursors were incorporated into mouse oocytes during the growth stages. The RNAase‐digestible label appeared first over nucleoli and meiotic chromosomes, becoming cytoplasmic after 24 hours, and remaining cytoplasmic through all remaining stages. Once incorporated the label persisted during subsequent oocyte growth and maturation through preimplantation embryo stages with apparently undiminished levels. It is suggested that this persistently labeled RNA represents maternal RNA stored for use during early embryonic development.
Mice produced from eggs fertilized in vitro at a very low sperm:egg ratio
Authors: Thadani Vijay M.
Published: June 2005

Zone‐free mouse eggs were fertilized in vitro very small numbers of randomly selected sperm that had been capacitated in vitro (5–10 sperm per egg). The resulting embryos developed to the blastocyst stage in vitro, and gave rise to progeny after transfer to recipient foster mothers. Under similar conditions zone‐intact eggs were not fertilized. These data support the view that most sperm are genetically and physiologically competent to fertilize an egg, provided that they can gain access to its surface.
Cell allocation in preimplantation mouse chimeras
Authors: Spindle Akiko
Published: June 2005

The mechanism of cell allocation in the preimplantation mouse chimera was studied in aggregation chimeras of 4‐ and 8‐cell stage embryos. To follow the fate of cells, some embryos were labeled by a 16‐h incubation (at the 2‐cell stage) with 3H‐thymidine. At the 4‐8‐cell stage both labeled and unlabeled embryos were treated with pronase to remove the zona pellucida and then aggregated in various combinations: one labeled 8‐cell and three unlabeled 4‐cell embryos (labeled 8‐cell chimeras); one labeled 4‐cell and three unlabeled 8‐cell embryos or two labeled 4‐cell and two unlabeled 8‐cell embryos (labeled 4‐cell chimeras). Autoradiography of air‐dried preparations of inner cell masses isolated from the chimeras at the blastocyst or late blastocyst stage by immunosurgery revealed that labeled 8‐cell embryos contributed a disproportionately large number (over 60%) of their descendant cells to the inner cell mass of labeled 8‐cell chimeras. By contrast, in labeled 4‐cell chimeras only 8% (with one labeled 4‐cell embryo) or 31% (with two labeled 4‐cell embryos) of inner cell mass cells were derived from the labeled embryos. These results suggest that cell allocation in preimplantation mouse chimeras is not a random process and that cells of embryos developing ahead of others are preferentially allocated to the inner cell mass.
Pulmonary oxygen diffusing capacity of the lizard Tupinambis teguixin
Authors: Glass Mogens L. , Johansen Kjell
Published: June 2005

Pulmonary oxygen diffusing capacity (DLO2) and perfusion (Q̇L) have been measured by a rebreathing technique in the lizard Tupinambis teguixin at 25°C and 35°C. Both variables increased with temperature and at 35°C the values were Q̇L = 35 ml·kg−1·min−1; and DLO2 = 4.29 μmol·kg−1·min−1· Torr−1. These values are low compared to those for similar‐sized mammals or birds.
High levels of glutathione attained during postnatal development of rat testis
Authors: Calvin Harold I. , Turner Sheila I.
Published: June 2005

The concentration of glutathione (GSH) in rat testis increases approximately 3‐fold between 8 and 29 days of age, coinciding with the initial wave of meiosis, and is then maintained during spermiogenesis. In the adult rat, mM tissue GSH concentrations rank approximately as follows: liver > testis = kidney > caput epididymidis. However, with respect to protein content, relative GSH levels are testis = liver > kidney. In addition to its possible role during meiosis, the high concentration of GSH attained by developing germinal epithelium may be necessary for the biosynthesis and processing of sperm proteins containing SH and SeH.
Cinephotomicrographic observations on intracellular bubble formation in Tetrahymena
Authors: Hemmingsen Edvard A.
Published: June 2005

A miniature cuvette pressure chamber for microscopy and highspeed (400 frames per second) cinephotographic recordings was developed to study intracellular bubble formation in Tetrahymena. The investigations show, for the first time, that intracellular bubble formation can occur, but only when the nitrogen gas supersaturations are higher than 150 atm. However, substantial fractions of the cell populations remain unaffected by exposures to gas supersaturations as high as 200 atm.
The presence of 17β‐hydroxysteroid dehydrogenase activity in preimplantation rat and mouse blastocysts
Authors: Wu Jung‐Tsung , Lin Guey‐Meei
Published: June 2005

When Day 5 rat blastocysts and Day 4 and 5 mouse blastocysts were cultured in 53 μl of medium containing 1340 or 2680 pg [3H]estradiol (E2), large amounts of [3H]estrone (E1) were detected in the medium at daily intervals for up to 5 days. This indicates the presence of 17β‐hydroxysteroid dehydrogenase in the embryos. The activity was higher at a higher concentration of E2 and was also higher in mouse than in rat blastocysts. In the mouse, the activity was higher in Day 5 than Day 4 blastocysts during the first day in culture; then it decreased in Day 5 but increased in Day 4 blastocysts. The importance of E2 in embryonic development and implantation as suggested by others may be related to the activity of 17β‐hydroxysteroid dehydrogenase.
A novel pore system in the eggshells of the mallee fowl, Leipoa ocellata
Authors: Board Ron G. , Perrott Hugh R. , Love Glyn , Seymour Roger S.
Published: June 2005

The outer orifice of the funnel‐shaped pores in the eggshell of the mallee fowl, Leipoa ocellata, contain irregularly shaped pieces of crystalline material. The whole of the outer surface of the shell is covered with spheres containing amorphous calcium phosphate but little organic material. Thus they would not be expected to support microbial growth and they would not be corroded by organic acids produced by microorganisms in the incubation mounds.
A new method for the immobilisation of teleost embryos for time‐lapse studies of development
Authors: King Gillian M. , Gordon Richard , Karmali Karim , Biberman Leslie J.
Published: June 2005

The transparent embryo of the zebrafish (Brachydanio rerio) can be dechorionated mechanically and immobilised up to 2 weeks in 5% methylcellulose mucilage so that its development can be followed by time‐lapse cinematography. The developmental sequence parallels that of the chorionated or dechorionated free‐swimming controls except the yolk supply is used at a slower rate, which allows normal development to be followed past the stage when feeding presents a problem. Because of its high viscosity the methylcellulose mucilage changes shape slowly and can be manipulated as if it were a solid gel. The embryo can easily be removed by placing a drop of the mucilage containing it in water so that the mucilage softens and the embryo swims away. After a short period of adjustment the swimming and feeding behaviours are identical to those of controls. This immobilisation procedure enables time‐lapse movies to be made of the development of embryos or larvae that normally show locomotory behaviour. This may be a useful procedure for immobilisation of other embryos for developmental studies and as a test system for water pollutants and teratogens that cause abnormal development.