bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct determination of the growth rate of Drosophila imaginal discs
Authors: Martin Presley F. 
Published: June 2005

AbstractA simple technique is described which allows the number of cells in the imaginal discs of Drosophila melanogaster to be determined directly, by dissociation of the tissue into single cells. This technique was used to determine the growth rates for the eye‐antenna, wing, leg, and haltere discs during the second and third larval instars. The results obtained for the number of cells present at particular stages and for the growth rates during this period are similar to those determined previously using either indirect or more tedious procedures.
Volume regulation in an intertidal oligochaete, Clitellio arenarius (Müller). I. Short‐term effects and the influence of the supra‐ and subesophageal ganglia
Authors: Ferraris Joan D. , Schmidt‐Nielsen Bodil 
Published: June 2005

AbstractTerrestrial oligochaetes demonstrate significant volume and osmoregulatory abilities that are under neurosecretory control. In the marine Oligochaete, little is known of volume or osmoregulatory capacities. However, histological evidence has linked cerebral neurosecretion and osmoregulation. The present study investigates water, ion, and volume regulation in an intertidal oligochaete and the effects of ablation of primary neurosecretory centers (supra‐and subesophageal ganglia) on these parameters. Control, sham‐operated, and ablated Clitellio arenarius were acutely transferred to diluted seawaters. Osmolality and Na, K, Cl (mEq/liter) concentrations were determined in total tissue water and in extracellular fluids. Extracellular volume was determined (using micropuncture techniques) as the fraction of the total tissue water in which 14C‐polyethylene glycol was distributed. With transfer to diluted seawater, all worms demonstrated hyperosmotic conformity. Tissue osmolality decreased in all animals at the same rate indicating no effect of ablation on integumental water permeability. Two phases of volume regulation were observed. In phase 1 (0–6 hours) osmolality decreased while water content (gm H2O/gm solute free dry weight = s.f.d.w.) increased both intra‐ and extracellularly. During this period, some volume regulation was accomplished in the control groups, particularly during the first 5 minutes, by the excretion of extracellular Na and Cl (μmoles/gm s.f.d.w.) which limited water gain. Ablated worms, reflecting less extracellular solute loss, gained more water than control groups. In phase 2 (6–18 hours) osmolality was constant, and all groups demonstrated a slow intra‐ (IC) and extracellular (EC) regulatory volume decrease. The solutes that accompanied volume loss were Na (EC), Cl (IC), and unmeasured solutes (IC). Reduction in intracellular solute content was the most significant loss occurring during this period with little difference among the groups tested. We hypothesize the primary effect of ablation is on extra‐ rather than intracellular volume regulation.
Physiology of cave arthropods in Hawaii
Authors: Ahearn Gregory A. , Howarth Francis G. 
Published: June 2005

AbstractLava tube caves in the Hawaiian Islands contain an impressive array of troglobitic arthropod species. These animals exhibit striking morphological adaptations to their subterranean environment including loss of eyes and body pigment, reduction or elimination of wings, and hypertrophication of chemosensory and tactile organs. Certain modifications of water balance and metabolic rates are also apparent in these cave‐adapted animals.Neither Hawaiian troglobites nor their surface relatives can absorb water vapor from a saturated atmosphere even following a period of prolonged desiccation, whereas both forms are able to restore water deficits adequately through drinking. Lava tube crickets (34.5 and 52.3 μg cm−2 hour−1 mmHg−1) and spiders (33.4 μg cm−2 hour−1 mmHg−1) possess greater integumentary permeabilities than their epigean relatives (crickets, 26.2; spiders, 3.1 μg cm−2 hour−1 mmHg−1).Hawaiian troglobitic crickets lack a diel metabolic rate (night = 279.5 ± 20.1; day = 280.8 ± 13.5 μl 02 gm−1 hour−1). The daily average metabolic rates of cave‐adapted (280.2 ± 15.3) and surface crickets (277.4 ± 9.8 μl 02 gm−1 hour−1) are not significantly different (P > 0.05), however, suggesting differential strategies of caloric utilization in the two environments which may be related to water availability.
Simultaneous measurement of evaporative water loss, oxygen consumption, and thoracic temperature during flight in a carpenter bee
Authors: Nicolson Susan W. , Louw Gideon N. 
Published: June 2005

AbstractThe carpenter bee Xylocopa capitata has a high wing loading (425 mg cm−2 in females with empty crops) and exhibits a very high mass‐specific oxygen consumption during flight (mean for free flight 52.3 ml O2 gm−1 hour−1). Evaporative water loss is also high during flight (26.6 mg gm−1hour−1) and is significantly correlated with rate of oxygen consumption (r = 0.73) as well as with temperature of the ambient air (r = 0.80) and the water vapor deficit (r = 0.66). No indication of active evaporative cooling was evident and the bees are true endotherms capable of rapid preflight thermogenesis. Analysis of the osmotic and ionic concentrations of the body fluids showed that no water stress was experienced by the bees.The use of suitable thermocouples and a sensitive capacitance‐type humidity meter in an open flow‐through system allowed instantaneous and simultaneous measurement of oxygen consumption, evaporative water loss, and thoracic temperature. All three variables fluctuated in close synchrony during preflight warmup, flight, and subsequent cooling.
Monoaminergic mechanisms associated with control of luminescence and contractile activities in the coelenterate, Renilla köllikeri
Authors: Anctil Michel , Boulay Danielle , Larivière Luc 
Published: June 2005

AbstractThe effects of monoamines and adrenergic drugs on luminescent responses and rachidial contractions were investigated in the colony of the sea pansy Renilla köllikeri. Of several transmitter candidates tested, only adrenaline induced localized, phasic luminescence at low concentrations. Propranolol (1 mM) depressed adrenaline‐induced and suppressed electrically stimulated luminescence, the latter being also abolished by 6‐hydroxydopamine (6‐OHDA) and reserpine. Desmethylimipramine (DMI, 20 μM), an uptake inhibitor of adrenergic neurons, potentiated luminescent responses to both adrenaline and electrical stimulation, and induced luminescence at higher concentrations. Pargyline, a monoamine oxidase inhibitor, produced DMI‐like effects. Rachidial contractions in Renilla are biphasic events which are usually spontaneous and rhythmic, or can be induced by electrical stimulation. Noradrenaline and adrenaline enhanced the second phase of ongoing rhythmic contractions, but failed to induce contractions. Reserpine and 6‐OHDA abolished electrically stimulated luminescence, but reserpine further depressed evoked contractions while 6‐OHDA failed to affect rhythmic or evoked contractions. DMI (0.5 mM) initiated rhythmic contractile activity in quiescent preparations. These observations suggest that adrenaline or an as yet unidentified catecholamine may be involved as a neurotransmitter in luminescence control. Noradrenaline and/or adrenaline act possibly as neuromodulators for rachidial contractions in the sea pansy.
Red cell metabolism in buffaloes and camels
Authors: Agar N. S. , Suzuki T. 
Published: June 2005

AbstractRed cell GSH, GSH regeneration rates, and the activities of ten enzymes were measured in the red blood cells of camels and buffaloes. The activity of G6PD was found to be much higher in both the species compared to that found in other ruminants such as sheep, goats, and cattle. Although there were no significant differences in the level of red cell GSH in the two species, there was a striking difference in the rate of GSH regeneration, the mean rate of 0.162 ± 0.009 μmoles/min/gHb in the camels was significantly higher than the 0.082 ± 0.011 μmoles/min/gHb observed in the buffaloes.
Effects of gravidity on the metabolism of the reproductively bimodal lizard, Sceloporus aeneus
Authors: Guillette Louis J. 
Published: June 2005

AbstractThe metabolic rates of gravid and nongravid females of two subspecies of Sceloporus aeneus exhibiting different reproductive modes (oviparity and viviparity) were compared. Both oviparous and viviparous gravid females exhibited a significant increase in oxygen consumption over that of nongravid females of either reproductive mode. Weight‐specific oxygen consumption also is greater in gravid than in nongravid females. The alteration in metabolic rate in gravid females is attributed to a fetal–maternal difference in this parameter‐that is, an altered maternal physiology associated with pregnancy.key words weight‐specific metabolism, reproduction,oxygen consumption,Sceloporus aeneus reptilia, squamata,iquanidae
Development of peroxisomes in amphibians. II. Cytochemical and biochemical studies on the liver, kidney, and pancreas
Authors: Dauca M. , Calvert R. , Ménard D. , Hugon J. S. , Hourdry J. 
Published: June 2005

AbstractThe ontogeny of catalase‐containing organelles was studied by cytochemical and biochemical methods in the liver, kidney, and pancreas during the development of Rana catesbeiana. The biochemical differentiation of peroxisomes in the liver and kidney was compared to that of Xenupus laeuis. Catalase activity was localized after incubation in DAB medium and studied biochemically by a spectrophotometric method. In Rana catesbeiana the number of catalase‐pos‐itive organelles per cell section is low in all three organs during premetamorphosis; their number increases substantially in the liver and kidney of froglets, while it remains almost stable in the pancreas. No further increase is observed in the adult. Biochemically, the liver, kidney, and pancreas of tadpoles exhibit, respectively, 12, 22, and 63% of the catalase activity found in the adult tissues. After metamorphosis an important increase of catalase activity is particularly noted in liver and kidney, the activity being, respectively, 43 and 77% of that of adult bullfrogs. On the other hand, no change in catalase activity in the liver and kidney is noted during the entire development of Xenopus laeuis. The present study illustrates the very different developmental pattern of catalase activity observed during the development of two anuran amphibians. The different developmental pattern of the same enzyme within the small intestine, liver, kidney, and pancreas in Rana catesbeiana is also stressed.
Measurement of enolase molecules in the single preimplantation rat embryo by an enzyme lmmunoassay system
Authors: Watanabe Tomomasa , Suzuki Fujiko , Kato Kanefusa 
Published: June 2005

AbstractThe amount of enolase (EC 4.2.1.11) molecules in a single preim‐plantation rat embryo was determined by an enzyme immunoassay system. An advantage of this assay system is its ability to distinguish each isozyme (αα, αγ and γγ forms) by using the specific antisera to a and y subunits. The isozyme of enolase was mostly the aa form through one‐cell to blastocyst stages, whereas the αγ and γγ forms were scarcely detected. Since the immunoassay system is highly sensitive, the minimum amount detectable being 1 amol(1 × 10−18 mole), the amount of aa form enolase could be determined in single embryos in all preimplantation stages. The results have revealed that the amount of aa form enolase molecules does not change through one‐cell to morula stages, but increases remarkably between morula and blastocyst stages.
Histologic evaluation of the sympathectomy induced by guanethidine sulfate in neonatal rats
Authors: Herskovits M. S. , Singh I. J. 
Published: June 2005

AbstractGuanethidine sulfate was administered to rats from birth to 14 days of age. Cell counts were carried out in the superior cervical sympathetic ganglion at 30, 45, and 90 days of age. Massive, permanent destruction of sympathetic ganglionic cells was demonstrated during the experimental period. Evidence for a natural loss of neurons during the morphogenesis of the superior cervical sympathetic ganglion is presented.
The regional distribution of poly (A) and total RNA concentrations during early Xenopus development
Authors: Phillips Carey R. 
Published: June 2005

AbstractXenopus laevis embryos were oriented and sectioned into six regions along one of three axes: animal‐vegetal, dorsal‐ventral, or right‐left. Total RNA (predominantly ribosomal RNA) and poly riboadenylate [poly (A)] were measured for each region during early embryogenesis. The concentrations of both total RNA and poly(A) are nonuniformly distributed during early development. Total RNA is approximately four‐fold more concentrated in the more animal portions than the more vegetal portions of the embryo. The dorsal‐most region contains a 1.5‐fold higher concentration than in the other five regions of the four‐celled embryo along the dorsal‐ventral axis. Poly(A) concentrations show temporal and regional specific changes in concentration during early development with higher concentrations more generally found in the animal‐most regions.
A study on melanogenesis and catecholamine biosynthesis during Bufo bufo development
Authors: Miranda Michele , Botti Dario , Ragnelli Anna Maria , Cola Mario Di 
Published: June 2005

AbstractTyrosinase and L‐DOPA decarboxylase activities have been investigated during Bufo bufo development since catecholamines and melanin are formed from common substrates in homologous cells. Catecholamines first appear at stage 13 (neural plate), but tyrosinase, at a very low level, and L‐DOPA decarboxylase are present throughout all of prior development. Hence, L‐DOPA decarboxylase activity is not likely to be correlated with the control of catecholamine synthesis, although at stage 17 it is mainly localized in the nonneural part of the embryo. The distribution of young melanosomes and L‐DOPA decarboxylase suggest a separation between melanogenesis and catecholamine synthesis.
Sperm nuclear decondensation in mammals: Role of sperm‐associated proteinase in vivo
Authors: Perreault Sally D. , Zirkin Barry R. 
Published: June 2005

AbstractPrevious studies from this (Zirkin et al., '80) and other (Marushige and Marushige, '78) laboratories have shown that proteinase associated with mammalian sperm nuclei is involved in thiol‐induced sperm nuclear decondensation and protamine degradation in vitro. The results of these in vitro studies suggested the exciting possibility that the sperm nucleus itself might contribute proteinase involved in its subsequent in vivo decondensation during fertilization. In the present study, microinjection methods were used to test this possibility directly. Control hamster sperm nuclei, which exhibited proteinase activity, decondensed when incubated in vitro with disulfide reducing agent. As expected, these nuclei also decondensed when microinjected into ovulated hamster oocytes and formed morphologically normal pronuclei. When the proteinase associated with isolated sperm nuclei was removed with 0.5 M salt or inhibited with nitrophenyl‐p‐guanidinobenzoate, the nuclei were rendered incapable of decondensing in response to disulfide reducing agent in vitro. However, when these nuclei were microinjected into eggs, they decondensed and transformed into pronuclei. These results provide direct evidence that sperm‐associated proteinase is not required for sperm nuclear decondensation and formation of the male pronucleus during fertilization.
Isolated osteoclasts and their presumed progenitor cells, the monocyte, in culture
Authors: Osdoby Philip , Martini Mary C. , Caplan Arnold I. 
Published: June 2005

AbstractOsteoclasts were isolated from the endosteal surface of day 19 embryonic chick tibias by mild trypsinization. Osteoclast enrichment was achieved by passing cell suspensions through Nitex screening of selective sizes, including the eventual selective retention of osteoclasts on 12 μm polycarbonate filters or by sequential sieving through Nitex screens and fractionation on Percoll gradients. The enrichment procedures produced osteoclast populations of 50–75% based on morphological criteria with the latter isolation method providing populations with less matrix debris. The results of light microscopy, transmission and scanning electron microscopic observations indicate that osteoclasts can be maintained in culture for up to 10 days with retention of osteoclast morphology. This morphology includes a specialized ruffled plasma membrane, large numbers of mitochondria, lysosomes, as well as a multinucleated cytoplasm. Furthermore, acid phosphatase and butyrate esterase histochemical measurements support these morphological observations. In addition, chick hatchling circulating monocytes were isolated and purified by Ficoll‐hypaque gradient centrifugation with subsequent adhesion to glass petridishes. With time in culture, these cells form multinucleated cells, but lack the ultrastructural complexity of the isolated osteoclasts. This report describes a unique culture system to study osteoclast function and illustrates the similarities and differences of this system to the monocyte‐to‐giant cell culture system.
Protein synthetic requirements for the outgrowth of trophoblast cells from mouse blastocysts
Authors: Blake Emily J. , Schindler Joel , Sherman Michael. I. 
Published: June 2005

AbstractMouse blastocysts cultured under optimal conditions attach to the surface of the culture dish and subsequently give rise to outgrowths of trophoblast cells. The migration of trophoblast cells appears to be analogous to their behavior during the invasive phase of implantation in utero. In these studies, we have attempted to determine the time of synthesis and nature of the products required for trophoblast outgrowth. Fourth‐day blastocysts were cultured in two different media: cNCTC, a nutrient medium supplemented with fetal calf serum, and PCMF, a simple preimplantation medium lacking amino acids and serum. Trophoblast outgrowth occurs in the former, but not in the latter, medium. Most blastocysts will give rise to outgrowths following as little as 12 hr of exposure to cNCTC at the appropriate time, even if they are subsequently placed in PCMF. Outgrowth fails to occur if blastocysts are treated with cycloheximide during the interval of exposure to cNCTC, whereas treatment with the antimetabolite after the period of culture in cNCTC does not block outgrowth. These observations are consistent with the view that protein(s) essential for trophoblast outgrowth are synthesized many hours prior to the actual event.
Decondensation of human sperm nuclei by glycosamineglycan‐sulfate from sea urchin egg
Authors: Delgado Néstor M. , Reyes Rosalina , Huacuja Luis , Carranco Armando , Merchant Horacio , Rosado Adolfo 
Published: June 2005

AbstractDecondensation of human and sea urchin spermatozoan nuclei has been induced by exposure of intact spermatozoa to glycosamineglycan‐sulfate (GAGs) extracted from eggs of the sea urchin, Toxopneustes roseus. Swelling of human spermatozoan nuclei commenced about 60 min after the addition of GAGs and, depending on the extract concentration, the proportion of swollen nuclei reach 90% after 6 h of incubation when 20 mg of GAGs per ml was used. Swelling of sea urchin spermatozoan nuclei could be induced also with GAGs and/or with heparin. Swelling commenced about 10 min after the addition of GAGs/heparin reaching 90–92% after 60 min of incubation with 5 mg GAGs/500 USP heparin per ml. Preincubation of spermatozoa with 10 mg/ml of trypsin soybean inhibitor did not interfere with the swelling action of the GAGs.
Recurrent germ‐line transmission of the teratocarcinoma genome from the METT‐1 culture line to progeny in vivo
Authors: Stewart Timothy A. , Mintz Beatrice 
Published: June 2005

AbstractMouse teratocarcinoma stem cells cultured in vitro provide the unique prospect of obtaining new strains of mice with genetic changes that have been predetermined, preselected, and precharacterized. This possibility rests upon the demonstrated capacity of the stem cells, after injection into blastocysts, to produce lineal cell descendants that are functional gametes. Thus far, only one in vitro line of teratocarcinoma cells has been founa capable of forming germ cells in vivo. The line, established in this laboratory from a 129 (agouti‐strain) embryo, was designated METT‐1 and was shown in previous reports to be karyotypically normal and chromosomally female (X/X); after introduction of the cells into C57BL/6 (non‐agouti‐strain) blastocysts, one mosaic‐coat female (out of nine that were test‐mated) had some offspring from the teratocarcinoma cell source. We report here results from an extension of this study. The new series was initiated in part to clarify the frequency of mosaic individuals with some reproductive cells of the tumor strain, as an indication of the practicability of the proposed genetic manipulation experiments. From among the first eight mice produced, a single female with a mosaic coat was test‐mated to a C57BL/6 male and produced progeny. An agouti (dominant‐color) 129‐derived male appeared in her second litter. The teratocarcinoma lineal provenance of this F1 animal was confirmed by its heterozygosity for the hemoglobin electrophoretic variants (Hbb locus) due to the 129 (diffuse‐type) and C57BL/6 (single‐type) strains. Thus, in our two series combined, the METT‐1 cell line has given rise to normal germ‐line progeny in a substantial frequency (2/10, or 20%) of tested females.
J10 lactate‐induced polycythemia in newts
Authors: Frangioni Giuliano , Borgioli Gianfranco 
Published: June 2005

AbstractSpecimens of Triturus cristatus carnifex (Laurenti) raised for about 3 weeks in a 3 gm/liter solution of sodium lactate present a slight alkalosis and a mean increase of about 35% in the red blood cell count in comparison to control animals raised in identically oxygenated water; analogous treatment with an equal molar concentration of sodium pyruvate produces only alkalosis. Since lactate alone determines an increase in the number of erythrocytes as does hypoxia, and hypoxia always induces an increase in plasma lactate levels, it can be deduced that erythropoietin (ESF) production is stimulated by an increase in plasma lactate and not directly by a lack of oxygen. The hypothesis that ESF in newts is produced by the “lactate‐sensitive cells” of the renal corpuscles, which hypertrophy after experimental anaemia or treatment with lactic acid salts, is indirectly confirmed.
Neuromuscular relationships in the asymmetric claws of Californian snapping shrimp
Authors: Stephens Philip J. , O'Connor Kathleen , Leferovich John M. 
Published: June 2005

AbstractThe asymmetric claws of Californian snapping shrimp (Alpheus californiensis) are comprised of a smaller pincer claw and a larger snapper claw. The present paper describes the morphology of the single closer muscle and the facilitation properties of an excitatory motor axon for both claws. In the snapper claw the closer muscle fibers are composed of uniformly long sarcomeres, measuring 10–15 μm in length. In the pincer the closer muscle fibers are of a smaller diameter and can be divided into two groups on the basis of sarcomere length. One group has short (2 and 3 μm) sarcomeres, while the other has intermediate (7 and 8 μm) sarcomeres. Microelectrode recordings from single closer muscle fibers showed that all fibers are supplied by the fast excitatory motor axon. The slow excitatory motor axon innervates only fibers on the dorsal and ventral surfaces of the closer muscle. Facilitation of excitatory junctional potentials (ejps), produced by stimulation of the fast axon with pairs of brief electrical shocks, revealed that at intervals above 100 ms no facilitation was recorded from either claw. At intervals below 100 ms, however, facilitation was recorded from pincer closer muscle fibers, but defacilitation or depression was recorded from the snapper. This was confirmed by making extracellular recordings of synaptic potentials from snapper closer muscle fibers.