bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recovery from environmental anaerobiosis and muscular work in the cockle, Cardium tuberculatum: Oxygen debt and metabolic responses
Authors: Meinardus‐Hager Georg , Gäde Gerd 
Published: June 2005

AbstractThe consumption of oxygen by Cardium tuberculatum, as well as the changes in levels of metabolites in tissue, were determined during recovery from 16 h of anoxic incubation and after exercise. Consumption of oxygen increased up to 3.5‐fold within 5 min of the termination of anoxic incubation or exercise. Control rates of oxygen consumption were restored within 10 h or 90 min, respectively (after environmental or functional anaerobiosis). With the transition to aerobic conditions or at the end of exercise, metabolites that had accumulated or been utilized during anoxia returned to levels near those of controls. No recovery phase, with an accumulation of the end products of anaerobic metabolism, was observed in Cardium tuberculatum. The time‐course for the consumption of oxygen during recovery was clearly related to metabolic events. During recovery from anoxic incubation, there was, initially, a short period of greatly enhanced consumption of oxygen, while the pools of phosphagens were replenished. During the subsequent 10 h of recovery, the rate of consumption of oxygen was slightly elevated and oxidation of the metabolic end products, D‐lactate and L‐alanine, took place. Recovery from exercise resulted in the rapid (30 min) and simultaneous replenishment of the pools of phosphagens and oxidation of octopine, while the oxygen consumption was greatly enhanced. A relationship was observed between the extent of the oxygen debt and the preceding stress (anoxia or exercise), and the duration of anaerobiosis.
Cardiovascular consequences of hypercalcemia during activity in two species of amphibian
Authors: Hillman Stanley S. , Withers Philip C. , Palioca Wayne B. , Ruben John A. 
Published: June 2005

AbstractExercise induced both a significant acidosis and hypercalcemia, measured as either total or ionic calcium in two species of amphibian, Bufo marinus and Rana catesbeiana. Hypercarbia induced a significant acidosis in both species but a significant hypercalcemia only in Bufo. Induction of hypercalcemia by infusion of Ca to concentrations equal to or greater than induced by exercise and hypercarbia had no significant effects in either species on mean arterial pressure, maximal rate of rise of systemic arterial pressure, blood flow rate, heart rate, pulse volume, or peripheral resistance during exercise. The ratio of ionic to total calcium was not significantly altered within a species by an experimental protocol. These data indicate that there are no discernible cardiovascular consequences during exercise of hypercalcemia induced by exercise or hypercarbia.
Innervation is necessary for the development of fast contraction kinetics of singing muscles in a katydid
Authors: Novicki Andrea , Josephson Robert K. 
Published: June 2005

AbstractThe twitch duration of mesothoracic wing muscles of the male katydid Neoconocephalus robustus (Insecta; Orthoptera; Tettigoniidae) decreases rapidly within the first 5 days of adulthood, to about half of its value in newly molted adults. To determine if this change is dependent upon neural input, male mesothoracic first tergocoxal muscles were unilaterally denervated on the second day of adulthood. The contraction kinetics of the denervated and contralateral innervated muscles were tested four days later. The development of rapid contraction kinetics was slowed or stopped in the denervated muscles, while the contralateral innervated muscles did become faster. Mesothoracic wing muscles of females do not develop faster contraction kinetics. When the female mesothoracic first tergocoxal muscle is denervated, there is no difference in twitch duration after 4 days between the innervated and contralateral denervated muscles. Therefore, denervation in newly molted adult male katydids interrupts a developmental program for the acquisition of adult contraction kinetics.
An autoradiographic analysis of N‐linked glycoconjugates in embryonic salivary gland morphogenesis
Authors: Bassett Kenneth E. , Spooner Brian S. 
Published: June 2005

AbstractThe synthesis, deposition, and loss of mannose‐bearing glyco‐conjugates during branching morphogenesis of embryonic mouse salivary glands has been evaluated. Day 13 embryonic mouse salivary glands were cultured for 44 hr, pulse labeled 4 hr with [3H]mannose, then fixed after 0, 2, 4, 8, or 24 hr, of chase in nonradioactive medium, and processed for autoradiography. Light microscopic autoradiograms of sectioned rudiments reveal extensive label within the epithelium, little label over the mesenchyme, and a concentration of radioactivity at the basal surface of the epithelium. Autora‐diograms of “chased” rudiments reveal a) no detectable loss of label from the epithelium or the basal epithelial surface over the first 8 hr, and b) significant label loss by 24 hr of chase at the basal epithelial surface, while moderate amounts of radioactivity remain throughout the rest of the epithelium. The [3H]bound material is insensitive to chondroitinase ABC, a glycosaminoglycan degradative enzyme, but is sensitive to tunicamycin presence in the culture medium.Earlier studies showed that embryonic mouse salivary glands cultured in medium containing tunicamycin (25 ng/ml) continued normal epithelial branching while epithelial growth was inhibited. The present autoradiographic studies of [3H]mannose‐labeled rudiments demonstrate that tunicamycin causes a significant decrease in radioactivity, relative to controls. Thus, our results suggest that epithelial branching activity is independent of control levels of mannose‐containing/tunicamycin‐sensitive, glycoconjugate deposition.
Isolation and partial characterization of a “spawning female‐specific substance” in the teleost, Oryzias latipes
Authors: Hamazaki Tatsuo S. , Iuchi Ichiro , Yamagami Kenjiro 
Published: June 2005

AbstractA “spawning female‐specific substance” (SF substance) [Hamazaki et al. (1985) J. Exp. Zool., 235:269–279] was isolated from the ascites fluid of the estrogen‐fed (EF) male or nonspawning female fish, Oryzias latipes, by gel filtration chromatography, followed by high‐performance ion‐exchange liquid chromatography (HPLC). Biochemical analyses revealed that the SF substance was a glycoprotein that contained 3.01% carbohydrates and showed 49,000 molecular weight (mw) on SDS‐PAGE. Amino acid composition and the carbohydrate content of the SF substance were similar to those of the glycoproteins, F1 and F2, which were purified from the hatching enzyme digest of the inner layer (zona interna) of egg chorion (egg envelope).The inner layer of chorion from ovarian egg (oocyte) was separable into three different glycoproteins, ZI‐1 (mw 76,000), Z1‐2 (mw 74,000), and ZI‐3 (mw 49,000) on SDS‐PAGE. The major glycoprotein, ZI‐3, was found to show the mw and amino acid composition that were almost identical to those of the purified SF substance. These results indicate that a substance that is almost the same as the major component glycoprotein of the inner layer of chorion, in terms of the biochemical as well as immunological properties, is present out‐side the ovary and is produced in the liver of the spawning female fish as well as the EF fish.
Protamine polymorphism in Xenopus laevis laevis
Authors: Risley Michael S. , Eckhardt Ronald A. 
Published: June 2005

AbstractProtamines from individual frogs of the subspecies Xenopus laevis laevis were compared by electrophoresis on polyacrylamide gels containing acetic acid, urea, and Triton X‐100 to determine if the expression of protamine genes differs among individuals. Two electrophoretic bands, SP2a and SP2b, appeared to be expressed as allelic variants. Of 33 frogs, 19 expressed only SP2a, 11 expressed both SP2a and SP2b, and three expressed only SP2b. Electrophoretic analysis of partial V8 protease digests could not distinguish the peptides released from SP2a and SP2b. Differences in sperm development between individuals were not detected by light or electron microscopy. The results suggest that protamine polymorphism can exist among individuals of a species without an apparent effect on sperm development or sperm function.
Plasma growth hormone levels in normal and stunted yearling coho salmon, Oncorhynchus kisutch
Authors: Bolton Jonathan P. , Young Graham , Nishioka Richard S. , Hirano Tetsuya , Bern Howard A. 
Published: June 2005

AbstractA homologous radioimmunoassay was employed to assess plasma and pituitary growth hormone (GH) levels in coho salmon (Oncorhynchus kisutch) smolts and stunts. Although stunts have significantly reduced body weights and lengths, their plasma GH levels were 5‐fold higher than those of either freshwater or seawater smolts. Pituitary GH content was also greater in the stunts than in either group of smolts. The presence of elevated GH levels in a group of animals with reduced growth rates suggests deficiencies in recptor and/or mediating systems as the cause of stunting.
Osmolyte processing in the gut and an important role of the rectum in the land slug, Ariolimax columbianus (pulmonata; arionidae)
Authors: Deyrup‐Olsen I. , Martin A. W. 
Published: June 2005

AbstractExperiments were carried out to investigate the role of the gut in the osmotic balance of the land slug Ariolimax columbianus. Previous investigators have shown that absorption of nutrients, calcium, and some heavy metals occurs in the slug's digestive gland and intestine. The only function suggested for the rectum, beyond transfer of the fecal mass, has been its possible involvement in lipid absorption. We collected hemolymph and fluids contained in different regions of the gastrointestinal tract and compared these with respect to osmotic pressure as well as to concentrations of ions (sodium, potassium, calcium, and chloride), glucose, and amino acids. The osmotic pressure of rectal contents was found to average one‐quarter the values of other fluids. In in vitro experiments sacs of intestine and rectum exposed to 1:4 mucosa:serosa osmotic gradients for 1 h showed transfer of fluid across the sac wall into the surrounding fluid. This transfer was significantly enhanced in the case of the rectum but not of the intestine, after dehydration or loss of hemolymph, and during immersion of the sacs in media containing the gastropod neurotransmitters FMRFamide, norepinephrine, and 5‐hydroxytryptamine, as well as arginine vasotocin. The data indicate that the rectum of the slug serves as a small but ready source of water available for use under conditions of acute water deficiency.
Involvement of thiol‐disulfide groups in the sensitivity of fully grown mouse oocytes to calcium‐free medium
Authors: De Felici Massimo , Dolci Susanna , Siracusa Gregorio 
Published: June 2005

AbstractThe lethality caused by calcium‐free medium (CFM) to fully grown mouse oocytes significantly decreases if a disulfide reducing agent (dithiothreitol, reduced glutathione, or L‐cysteine) is added to the medium. In this condition, most of the surviving oocytes do not spontaneously resume meiosis. We also show that the sulfhydryl content of fully grown oocytes, estimated by monobromobimane labeling, rapidly decreases during culture in CFM. The hypothesis is discussed that lethality of oocytes cultured in CFM may be a consequence of an alteration of thiol‐disulfide balance.
The Chaetopterus vitelline envelope is not necessary for the gamete interactions that lead to fertilization
Authors: Polk Patricia M. , Anderson Winston A. , Eckberg William R. 
Published: June 2005

AbstractIt has been recently shown that, in several genera of annelids, including Chaetopterus, fertilizing sperm attach to and fuse with egg microvilli which penetrate the vitelline envelope. This suggests that the annelid vitelline envelope may have no direct or obligatory role in normal fertilization. The present study was undertaken to investigate the involvement of the vitelline envelope in fertilization in Chaetopterus experimentally, by examining the fertilization of vitelline envelope‐free eggs quantitatively and qualitatively. Brief exposure of the eggs to isotonic sucrose‐EDTA removed the vitelline envelope as determined by both phase‐contrast and electron microscopy, rendered the eggs more sensitive to polyspermy and substantially reduced the binding of supernumerary sperm to eggs but did not decrease fertilizability as determined by sperm dilution assay and did not make the eggs more sensitive to cross‐fertilization. The events of fertilization were examined by electron microscopy and found to be very similar in vitelline envelope‐free eggs to those in intact eggs. We conclude that the vitelline envelope in Chaetopterus has binding sites for sperm but that it has no obligatory role in fertilization and is primarily involved in the prevention of polyspermy.
The regulation of amino acid metabolism during hyperosmotic stress in Acanthamoeba castellanii
Authors: Poulin Richard , Larochelle Jacques , Hellebust Johan A. 
Published: June 2005

AbstractThe effects of hyperosmotic stress on amino acid metabolism have been examined in Acanthamoeba castellanii incubated in a defined growth medium. Following hyperosmotic shock, the rapid appearance in the medium of previously ingested proline indicated a rapid release of pinosome contents induced by osmotic dehydration. Initially endocytotic uptake and protein synthesis were both markedly inhibited, but they recovered over the following hours. Total cell proteins decreased by 20% within 30 minutes after hyperosmotic stress, and this decrease was concomitant with a rapid accumulation of free ninhydrin‐positive substances.Following a hyperosmotic shock, free alanine, glutamate, and proline transiently accumulated, in this sequence. Aminooxyacetate prevented the accumulation of alanine while greatly stimulating that of glutamate, but its effect on proline accumulation was small. In cells incubated with radioactive alanine, the accumulation of free alanine proceeded mostly from unlabeled precursors and coincided with a high rate of radioactive glutamate synthesis. This newly synthesized glutamate was extensively converted into proline, while proline synthesis from ornithine was barely stimulated. During acclimation to hyperosmotic conditions, osmoregulatory mechanisms in A. castellanii appear to rely only transiently on free amino acids, particularly on those whose access to main metabolic pathways is not allosterically regulated.
Experimental results on cell volume, growth rate, and macronuclear DNA variation in a ciliated protozoan
Authors: Santangelo Giovanni , Barone Enrico 
Published: June 2005

AbstractSome species of ciliated protozoans vary their body volume when fed on preys of different sizes. This peculiarity has offered us the opportunity to examine the relationship between changes in cell volume, amount of macronuclear DNA (maDNA), and cell division rates in subclones derived from a single clone of the ciliate Blepharisma japonicum (Order Heterotrichida). Our results demonstrate that food‐induced size changes in this single‐celled organism are accompanied by substantial changes in maDNA content and in reproduction (cell division) rate. We find a strong, direct linear correlation between cell volume and maDNA quantity, and an inverse linear correlation between cell volume and reproduction rate. No correlation between cell reproduction rate and maDNA amount was found. We conclude that food‐induced coordinate change in cell volume, maDNA content, and cell division rate in this organism may be an effective mechanism for rapid phenotypic change in response to variable environmental conditions.
Flow cytometric analysis of ploidy in the axolotl, Ambystoma mexicanum
Authors: Tank Patrick W. , Charlton Ronald K. , Burns E. Robert 
Published: June 2005

AbstractAlthough recent experiments on pattern formation during amphibian limb regeneration have relied on the use of triploid marked cells, the purity of the triploid donor has not been proven. To test the purity of the donor, blood (which contains noncycling nucleated red blood cells) was collected from the gills of 12 pressure‐induced triploid axolotls from two unrelated spawnings. Blood was also collected from 12 untreated sibling animals to serve as diploid controls. The blood samples were placed into a propidium iodide stain solution that had been adjusted to amphibian tonicity by the addition of distilled water. Samples were analyzed on an EPICS V (Coulter) flow cytometer. A minimum of 20,000 cells were analyzed in each sample at a flow rate that did not exceed 1,000 cells/second. In the diploid group, 88.6% of the cells were collected in channels of the DNA histogram corresponding to a 2C G1/G0 DNA content (channel 71±10) and 0.9% were collected in channels corresponding to a 3C G1/G0 DNA content (channel 106±10). In the triploid group, 99.2% of the cells were collected in nondiploid channels and only 0.8% were collected in channel 71±10. Utilizing the average peak channel number for the diploid group of 12 animals an average haploid channel number of 35 was calculated. The triploid group of animals exhibited DNA ploidy that averaged one haploid channel number above that of the diploid group. Based on forward angle light scatter, nuclei obtained from triploid red blood cells were observed to be larger than nuclei from diploid blood. Preliminary data are presented which demonstrate that the ploidy characteristics of solid tissues (brain, cornea, spleen, muscle, and limb blastemal mesenchyme) agree with those presented for blood.
Role of peanut‐lectin‐affinity molecules (PLAM) on primordial germ cells in the initial determination of sex in anura
Authors: Shirane Terukiyo 
Published: June 2005

AbstractPeanut lectin (PNA) or N‐acetylgalactosamine (galNA, a part of the disaccharide unit which is recognized by PNA) was injected into the coelomic cavity of anuran larvae at the developmental stages during which the genital ridges were growing, and the effect of these compounds on the initial determination of gonadal sex was examined. The treatment with PNA tended to inhibit (or perturb) the expression of feminizing gene(s) in Rana japonica, and of both feminizing and masculinizing genes in R. nigromaculata. In contrast, treatment with galNA suppressed the expression of masculinizing gene(s) considerably. In terms of the initial determination of gonadal sex during normal development, these results suggest that the PNA‐affinity molecule (PLAM) of primordial germ cells acts as a trigger for the expression of genes that control sexual differentiation of somatic cells. Furthermore, the somatic cells (perhaps mesenchymal and/or epithelial cells), which respond to the stimulus via the PLAM of primordial germ cells, may differ in terms of the threshold for such a response between genetic males and females. This result suggests the mesenchymal and/or epithelial cells are not sexually predetermined, but rather that sexual determination follows the response to some signal(s) mediated by the PLAM.
Metabolic test of volatile odor labels as kin recognition cues in honey bees
Authors: Moritz Robin F. A. , Southwick Edward E. 
Published: June 2005

AbstractThe ability of worker honey bees to discriminate between kin and non‐kin was revealed using a metabolic bioassay. Groups of workers (test group) exposed to odors of unrelated bees (odor group) showed short‐term increases in metabolic activity. The magnitude of the metabolic reaction was closely correlated with the genetic relationship between odor and test groups. Worker test groups reacted to both worker and drone odor groups whereas drone test groups did not respond in this bioassay. The results support the theory of inclusive fitness.
Blood‐gas, acid‐base, and electrolyte responses to exercise in larval Ambystoma tigrinum
Authors: Rohrbach Jay W. , Stiffler Daniel F. 
Published: June 2005

AbstractLarval Ambystoma tigrinum were non‐occlusively cannulated in the truncus arteriosus and allowed to recover 20–24 h. Upon recovery, control blood samples were removed, and the animals were exercised to exhaustion by encouraging swimming with a sponge forceps. The exercise led to a 5–6 fold increase in plasma lactate concentration which persisted 4–8 h. This lactacidosis caused the blood pH to drop from about 7.72 to below 7.10 in 30 min. Recovery was complete after 8 h. The acidosis was mixed with a pronounced respiratory component as P more than doubled during the same period. Bicarbonate concentration decreased from 12 mM to about 6 mM following exercise and recovered over the following 8 h. Similarly, strong ion difference was depressed following exercise but recovered during the ensuing 8 h. When exercised animals were forced to recover in running distilled water to deprive cutaneous ion transport mechanisms of access to ions, the results were quite different. The recoveries of pH, [HCO3−], and strong ion difference lagged 1–4 h behind the recoveries of these parameters in the tap water group, suggesting the participation of cutaneous ion transport in the recovery process. Ionic flux measurements demonstrated an increase in Na+ influx during the recovery period as well as increases in both Na+ and Cl− effluxes. The increases in efflux were much larger than observed increments in influx, placing the animals in negative ion balance and obscuring the significance of the changes in influx to acid‐base balance. Measurement of circulating aldosterone revealed a large increase in the concentration of this steroid hormone during recovery.
Plasma levels of glucose, alanine, lactate, and β‐hydroxybutyrate after mammalian insulin treatment in the American bullfrog (Rana catesbeiana)
Authors: deRoos Roger , Rumpf Ronald P. 
Published: June 2005

AbstractSerial blood samples were collected from the adult American bullfrog (Rana catesbeiana) via a non‐occlusive cannula chronically placed in the systemic subdivision (aortic) of the right truncus arteriosus. Plasma glucose, alanine, lactate, and β‐hydroxybutyrate levels were estimated by standard enzymatic procedures. The metabolites remained relatively stable in the control animals during the 8‐day experiments. A single infusion of mammalian insulin (5, 15, or 45 IU/kg body weight) via the cannula depressed plasma glucose and alanine to near or below detectable levels that required a minimum of 3 days to return to approximately the time‐zero levels. Plasma lactate also fell severely after the infusion, but subsequently displayed precipitous surges followed by sharp declines on days 1 and 3, and also in some animals on day 5. In contrast, plasma β‐hydroxybutyrate levels were not significantly altered by insulin. Despite the severe depressions of plasma glucose, alanine, and initially lactate, no symptoms were observed in the bullfrogs infused with 5 or 15 IU of insulin. The carnivorous adult bullfrog consumes abundant protein and lipid, but little carbohydrate, and is adapted to periods of food scarcity. The results are consistent with the hypothesis that the bullfrog may rely on non‐esterified fatty acids and ketone bodies as primary energy sources. Glucose, most of which must be synthesized, probably serves to maintain muscle glycogen reserves that are used for anaerobic glycolysis when the animal is engaged in predation, escape, or other vigorous activity. If other tissues and organs require glucose as a fuel, the amounts must be exceptionally small.