bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amino acids can induce nondisjunction during maturation of mammalian oocytes in vitro
Authors: McGaughey Robert W. 
Published: June 2005

AbstractCertain chromosomal disorders in mammalian embryos are traceable to meiotic errors during oocyte maturation. This report evaluates the influence of amino acids on meiotic maturation in vitro of oocytes from pigs, hamsters, and rats. The results indicate that maturing porcine oocytes respond not only to 1‐glutamine (1‐gln) but also to 1‐isoleucine (1‐ileu) in complex or chemically defined media by exhibiting significantly (P < .05) increased incidences of nondisjunction when compared with oocytes in control medium. Nondisjunction was highly correlated (r = 0.981) with dose of 1‐gln in porcine oocytes (incidences of maturing oocytes exhibiting nondisjunction were 19.3%, 39.7%, 41.5%, 66.2%, and 88.5% at l‐gln concentrations of 0 mM, 0.5 mM, 1.0 mM, 3.0 mM and 10.0 mM, respectively). Hamster oocytes also exhibited significantly (P < .05) increased nondisjunction when cultured in medium containing l‐gln (52% of maturing cumulus‐enclosed oocytes exhibited nondisjunction in medium with 3.0 mM l‐gln vs. 6.3% in control medium). Denuded hamster oocytes also responded to l‐gln (35% exhibited nondisjunction in 4.0 mM l‐gln, 8% in control medium). In contrast the incidence of nondisjunction in rat oocytes was not increased significantly by l‐gln over a concentration range of 0–12.0 mM. This study demonstrates that maturing oocytes respond to certain environmental conditions by undergoing chromo‐somally abnormal maturation. Specifically, amino acids can induce nondisjunction when present in elevated concentrations during oocyte maturation. The amino acid influence not only was dose dependent for porcine oocytes but also was species specific. These findings suggest that an unbalanced maternal environment might promote chromosomally abnormal meiotic maturation in vivo, and that culture media must be carefully selected to allow chromosomally normal oocyte maturation in vitro. This study defines a potentially useful experimental system for the further analysis of nondisjunction in mammalian oocytes.
Patterns of energy metabolism in the stone crab, Menippe mercenaria, during severe hypoxia and subsequent recovery
Authors: Albert J. L. , Ellington W. R. 
Published: June 2005

AbstractSpecimens of the stone crab, Menippe mercenaria, survived severe hypoxia (PO2 < 8mm Hg) for at least 12 hr at 28–30°C. During the time course of 12 hr of hypoxia, hemolymph L‐lactate levels rose to 30–50 μmoles/g wet wt. There was a slight elevation of L‐alanine levels, whereas succinate was found in only trace quantities in the hemolymph. Pronounced metabolic changes took place in the heart, cheliped closer, and leg socket muscles during severe hypoxia. L‐lactate accumulated to levels ranging from 16–20 μmoles/g wet wt. There were pronounced changes in high‐energy phosphate levels in the cheliped closer and leg socket muscles. Taking into account expected intra‐ and extracellular water content, the calculated intracellular lactate content in the three muscles investigated is substantially less than the hemolymph lactate concentrations. Part of this reverse concentration gradient may be accounted for by the reduction in lactate activity due to cation‐lactate complex formation. Hemolymph calcium and magnesium concentrations rose considerably during severe hypoxia. During recovery from severe hypoxia, approximately 50% of the accumulated lactate in the hemolymph was cleared in 6 hr. Hemolymph lactate and alanine levels returned to near control levels after 24 hr of recovery. This study shows that the stone crab, M. mercenaria, survives severe hypoxia by a reliance on glycogen fermentation to lactate. This species is capable of tolerating high levels of accumulated lactate.
Differentiation and distribution of annulate lamellae in growing oocytes in the newt, Cynops pyrrhogaster
Authors: Imoh Hiroshi , Terahara Tomoko 
Published: June 2005

AbstractStages of oocyte development in Cynops pyrrogaster are defined, and changes of annulate lamellae in their fine structure, number, sizes and locations during oogenesis are described. The results show that two different types of annulate lamellae occur during oogenesis. One type differentiates in or at the periphery of vesicle‐rich cytoplasm at the early stages of vitellogenesis and increases in number and size. The maximum number of about 40 stacks per median section of oocyte is reached at the stage of complete differentiation of the animal and the vegetal hemispheres. In these growing oocytes, all the stacks show elongate appearances and tetragonal arrangements of annuli as common characteristics. A second type of stacks of annulate lamellae is added anew in full‐grown oocytes, increasing the number of stacks per median section of the oocyte to about 90. The new stacks occur in close contact with electron‐dense bodies in the cytoplasm and have a massive appearance and hexagonal array of annuli. It is suggested that they appear coincidentally with the onset of oocyte maturation. The possible significance of the observed results is discussed.
Electron microscopic observations on sperm entry and pronuclear formation in naked eggs of the rose bitterling in polyspermic fertilization
Authors: Ohta Tadayuki 
Published: June 2005

AbstractUnfertilized eggs of the rose bitterling (Rhodeus ocellatus ocellatus) were squeezed out of females that had an elongated ovipositor and were dechorionated mechanically with fine forceps in physiological saline. The dechorionated eggs were transferred into fresh water then inseminated at once by spermatozoa of the same species. A large number of spermatozoa was found on the surface of eggs that had not yet had cortical reaction following insemination. The surface of the naked eggs responded by formation of many small cytoplasmic protrusions (viz., fertilization cones) at sperm attachment sites. The formed fertilization cones were rosettelike structures formed by the aggregation of some bleblike swellings devoid of microvilli and microplicae. About 10 min after insemination, the fertilization cones retracted, but marks of their presence characterized by less microvilli and microplicae remained in the eggs 15 min after insemination. Many spermatozoa penetrated into the cytoplasm of each naked egg. The sperm nuclear envelope disappeared by means of vesiculation resulting from fusion of the inner and outer membranes. The sperm nucleus decondensed and developed into a larger male pronucleus. Smooth‐surfaced vesicles surrounded the decondensing sperm nucleus and formed the new male pronuclear envelope. Sperm mitochondria and flagella were found in the egg 15 min after insemination. The response of the egg surface to sperm entry and pronucleus formation are discussed.
Cotical granule exocytosis in sea urchin eggs is inhibited by drugs that alter intracellular calcium stores
Authors: Stapleton Connie L. , Mills Lora L. , Chandler Douglas E. 
Published: June 2005

AbstractIn sea urchin eggs fertilization is accompanied by cortical granule exocytosis, a secretory event thought to be initiated by release of intracellularly sequestered calcium. We have examined the effect of two drugs on this process: chlortetracycline (CTC), a known chelator of intracellular calcium, and 8‐(N,N‐diethylamino)octyl‐3,4,5‐trimethoxybenzoate (TMB‐8), an antagonist of intracellular calcium release in both skeletal and smooth muscle. Preincubation of eggs for 10 min with either CTC or TMB‐8 blocked sperm entry, inhibited the burst of 45Ca2+ efflux normally seen postinsemination, and prevented fertilization envelope elevation. Half‐maximal inhibition occurred with 200 μM CTC and 60 μM TMB‐8. Electron microscopy confirmed that cortical granule exocytosis had been blocked, although inhibition was not due to a direct effect on exocytosis. CTC and TMB‐8 had no effect on Ca2+‐stimulated granule fusion in isolated egg cortices. Rather, these drugs block the early events in egg activation: sperm incorporation and triggering of exocytosis. These two effects appear to be independent since addition of either drugs just before insemination permits sperm entry but inhibits calcium release and cortical granule exocytosis.
Thermoregulatory responses to photoperiod by kangaroo rats (Dipodomys ordii): Influence of night lighting on nonshivering thermogenesis and resting metabolism
Authors: Gettinger Ronald D. , Ralph Charles L. 
Published: June 2005

AbstractThe influence of photoperiod on resting oxygen consumption and nonshivering thermogenesis of winter‐acclimatized kangaroo rats was determined by exposing freshly captured animals to 10‐week controlled photoperiod treatments. Three treatments were employed: (1) long days (LD) = 16L:8D, (2) short days (SD) = 8L:16D, and (3) short days interrupted with 15 min light at midnight (SDL). Thermoneutral oxygen consumption was uninfluenced by treatment, and posttreatment values were not different from pretreatment values. Below thermoneutrality, mean values for oxygen consumption and norepinephrine(NE)‐induced thermogenesis each were significantly greater in the SD group than they were in either the LD or SDL groups. Furthermore, oxygen consumption of LD and SDL groups, and NE‐induced thermogenesis of LD and SDL groups were indistinguishable. Posttreatment oxygen consumption and NE‐induced thermogenesis of the SD group were not different from pretreatment values. These results indicate that thermogenic capacities of kangaroo rats are strongly influenced by photoperiod. The similarities of responses by the LD and SDL groups indicate that the length of the dark period is of importance, and indirectly support suggestions that the pineal gland, through its nocturnal secretion of melatonin, may be involved in the transduction of photic information.
Enzymatic activities during evolution of the cement gland in Xenopus tadpoles
Authors: Weets J. , Picard J. J. 
Published: June 2005

AbstractThe activities of the hydrolases, α‐L‐fucosidase, N‐acetyl‐β‐D‐glucosaminidase (NAG), and zpacoumase appear to be involved in the regression of the cement gland in Xenopus laevis. The involution of the gland is marked by an important rise of the total as well as the specific activities of α‐L‐fucosidase and zpacoumase. The specific activity of α‐L‐fucosidase and of zpacoumase increases about five‐fold and eight‐fold, respectively, after 12 days of development. Although total activity of NAG decreases during involution, its specific activity undergoes an increase of 93% after 12 days. In contrast, there is a dramatic loss in the total and specific activity of aldolase, used as a control enzyme.The behaviour of these four enzymes is strikingly different in the epidermal tissue adjacent to the gland. Their activity remains stable during the developmental period considered. These observations demonstrate that possible contamination of the explanted gland by surrounding tissue is not responsible for the observed increase in hydrolytic activity in the gland.
Demonstration of sperm chemotaxis in Echinodermata: Asteroidea, Holothuroidea, Ophiuroidea
Authors: Miller Richard L. 
Published: June 2005

AbstractThe sperm of starfish (Asteroidea), sea cucumbers (Holothuroidea), and brittle stars (Ophiuroidea) are chemotactically attracted to the tip of a micropipette releasing very small volumes of egg water or seawater solution of an alcoholic extract of ovaries or spawned eggs. The sperm are unresponsive to injections of seawater or a weak solution of ammonium chloride in seawater. No other echinoderm tissue tested yields an extract with sperm‐attracting activity. A complex set of species‐specificities has been demonstrated between many of the genera and species used in these experiments. Plotting of the paths of chemotactic sperm reveals that they approach the tip of the pipette along a path consisting of small loops alternating with straight segments orientated directly up the gradient. This is similar to the chemotactic behavior previously reported for the sperm of hydrozoans, molluscs, and urochordates. Sperm velocity does not change in response to the sperm attractant. Attracted sperm remain motile long after they have been attracted and do not agglutinate. In at least some cases the attraction response is reversible. This is the first direct evidence of sperm chemotaxis in echinoderms.
X‐ray micro analyses of cations (Na, K, Ca) and anions (S, P, Cl) in uterine secretions during blastocyst implantation in the rat
Authors: Nilsson B. Ove , Ljung Leif 
Published: June 2005

AbstractThe mass changes of sodium, potassium, and calcium ions in the rat uterine secretion at blastocyst delay, activation, and attachment have been estimated with X‐ray microanalyses of samples of uterine secretions absorbed by small Sephadex beads. A quantification of the ions was attempted by using a standardized coat of gold on the beads as a reference element for normalization of the ion peaks and by fitting the normalized values into corresponding linear regression equations obtained from measurements of step‐wise dilutions of a control rat serum.The concentrations of sodium observed at delay, activation, and attachment were 117, 201, and 203 mEq/l, respectively, and those of potassium were 6, 18, and 19 mEq/l, respectively. Calcium values were about 2 mEq/l and decreased at attachment. Among the anions, only the chloride concentration increased at activation and attachment.
Effects of redox agents on glucose‐6‐phosphate dehydrogenase isozymes and enzyme activity in sea urchin eggs and zygotes
Authors: Sparling (Barber) Mary Lee , Killeen Timothy , Sinisgallo Yolanda , Yabuta Craig 
Published: June 2005

AbstractGlucose‐6‐phosphate dehydrogenase (G6PD) is present in different mixtures of interchangeable states of aggregation in each of the supernatant and pellet fractions of unfertilized and fertilized sea urchin eggs. These states are each altered differently by redox agents, as shown by changed electrophoretic isozyme patterns and altered filtration retention following treatment by diamide, oxidized glutathione, reduced glutathione, ascorbate, or dithiothreitol. Activity levels of G6PD are altered by redox agents, probably as a result of change in aggregation state or change in association with inhibitory associated molecules. This suggests that there are control mechanisms for G6PD that are in different conditions in unfertilized vs. fertilized stages and supernatant vs. pellet compartments, resulting in different states of G6PD in the isolates.
A metabolic test for the quantitative analysis of alarm behavior of honeybees (Apis mellifera L.)
Authors: Moritz Robin F. A. , Southwick Edward E. , Breh Michael 
Published: June 2005

AbstractThe reaction of a group of 40 worker honeybees to exposure to the major compound of the alarm pheromone Iso‐pentyl‐acetate (IPa) can be easily quantified by their metabolic response. A flow through system oxygen consumption of the bees shows a characteristic increase within 30 sec after the application of IPA. There are significant differences in response among colonies in the tested population; these were most extreme for 4‐day‐old workers. As there is a highly significant correlation between the colony defense in the field and the metabolic laboratory test, this technique may be usable as a routine in breeding programs for honeybees with low defensive behavior.
Electrophoretic patterns of hemoglobin and oxygen binding properties of blood of Anostomidae fishes from Parana‐Pardo‐Grande hydrographic basin (São Paulo State, Brazil)
Authors: de Almeida‐Val Vera Maria Fonseca , Schwantes Arno Rudi , Val Adalberto Luis 
Published: June 2005

AbstractThe electrophoretic patterns of hemoglobin (Hb) and the functional properties of blood of seven migratory fish species, in two different kinds of habitat during both the rainy and dry seasons, were studied. All species showed multiple hemoglobins and very similar electrophoretic patterns except for Schizodon nasutus, which showed two cathodal components. The functional properties of blood reflect those electrophoretic patterns, since all species showed very little or no Bohr effect during each situation studied. Data on Leporinus obtusidens blood (during the rainy season), from both lotic and lentic environments, showed a normal Bohr effect (ϕ = −0.073). Similarly, Schizodon nasutus and Leporinus friderici from a lotic environment during the dry season were compared and showed a reverse Bohr effect (ϕ=0.042). In the other 14 situations, only Leporinus elongatus from a lentic environment during the rainy season showed a statistically significant difference in log P50 values from the other fishes.
Escape reflex development during posterior regeneration in the earthworm, Eisenia foetida
Authors: Welch Margaret F. , Drewes Charles D. 
Published: June 2005

AbstractMorphological and electrophysiological correlates of giant nerve fiber development were examined during posterior segmental regeneration in the earthworm, Eisenia foetida. Seven days after amputation of the last 40 segments a small undifferentiated tail bud was evident. Tactile stimulation of this bud evoked all‐or‐none lateral giant fiber (LGF) spikes in original (substrate) segments adjacent to the bud, suggesting an early expansion of the LGF sensory field into the bud. This idea was further supported by experiments involving selective cutting of (and electrical recording from) ventral nerve cord and segmental nerves in the substrate segment immediately adjacent to the bud. By 12–16 days after amputation, segmental delineation of the bud was completed, lateral and medial giant fibers were evident in cross sections of the bud, and all‐or‐none giant fiber spikes were detected in surface recordings from the bud. LGF spikes, evoked by touching any of the bud segments, were readily conducted (velocity ≅ 1.0 m/s) along the bud and into substrate segments. During the next few weeks, giant fiber conduction velocities increased gradually in the bud and eventually were comparable to those in normal posterior segments. The patterns of conduction velocity increases during posterior segmental regeneration closely paralleled those of normal post‐embryonic development in posterior segments.
Accumulation of RNA in blastocysts during embryonic diapause and the periimplantation period in the western spotted skunk
Authors: Mead Rodney A. , Rourke A. W. 
Published: June 2005

AbstractThe in vivo incorporation of 3H‐uridine into RNA was studied in delayed implanting and activated blastocysts obtained from 33 western spotted skunks. 3H‐uridine was incorporated into RNA by all blastocysts; however, significantly more label was incorporated as blastocyst diameter increased. Activated blastocysts with diameters of 1.6 mm or greater on average incorporated 65 times more 3H‐precursor in 5 hr than diapausing blastocysts with diameters of 1.1 mm or less. Polyadenylated RNA was likewise synthesized by delayed implanting and activated skunk blastocysts; however, the proportion of polyadenylated RNA synthesized by the former was greater than in the latter (43.9% vs. 27.5%). Our data suggest that the transition from embryonic diapause to fully activated blastocysts first occurs gradually for several days before entering a 1–2‐day period of rapid development characterized by an abrupt increase in RNA accumulation.
Electrical activity at metamorphosis in larvae of the sea urchin Lytechinus pictus (Echinoidea: Echinodermata)
Authors: Satterlie Richard A. , Andrew Cameron R. 
Published: June 2005

AbstractTwo types of electrical potentials were recorded from competent echinopluteus larvae of Lytechinus pictus. The first was associated with reversal of cilia that line the ridges of larval epaulettes. Ciliary reversal potentials were recorded from all parts of the larvae and from isolated body parts. Estimated conduction velocity of ciliary reversal potentials was 10–20 cm/s. The second type of potential was largest when the electrode was placed over the urchin rudiment. Rudiment potentials could not be recorded from isolated epaulettes and could not be correlated with any obvious behavior of the larva.Both potentials increased in frequency when a larva was brought in contact with a “conditioned” substrate. Ciliary reversal potential frequency increased six‐ to seven fold within a minute or two of contact and remained elevated until the point of partial tissue collapse during metamorphosis. Rudiment potential frequency also increased, but only three‐ to five fold and with a longer latency (3–6 min to peak frequency). Rudiment potentials maintained an elevated level of firing through total tissue collapse, at which time the larvae were electrically silent. Attempts to record from juvenile urchins, to determine the fate of the rudiment potential system in the final stage of metamorphosis, were unsuccessful.
C pigment locus mutants of the fowl produce enzymatically inactive tyrosinase‐like molecules
Authors: Oetting W. S. , Churilla A. M. , Yamamoto H. , Brumbaugh J. A. 
Published: June 2005

AbstractThree albino mutants of the fowl were tested for tyrosinase activity. Two of these mutants (c and ca) are alleles at the autosomal C locus, while the third mutant (sal) is sex‐linked. Both the standard type, E, and sal are tyrosinase positive whereas the two C mutants are tyrosinase negative. Anti‐chicken tyrosinase mouse serum was produced and all four genotypes were found to have cross‐reacting material to this antiserum. Tyrosinase from the standard type was isolated and its location on denaturing two‐dimensional gels determined. A co‐migrating series of spots was found within the protein pattern of both the standard type and the tyrosinase positive albino, sal. The same pattern of spots was also observed for c and ca with no apparent change in either the pI or the molecular weight. Transmembrane blots also showed spots that reacted with anti‐tyrosinase serum in all four genotypes and that migrated to the same location as that of standard tyrosinase. It is proposed that both c and ca are CRM+ mutants which produce tyrosinase‐like molecules that are inactive due to a change that is electrophoretically and antigenically “silent”.
Calcium mobilization, water balance, and growth in embryos of the agamid lizard Amphibolurus barbatus
Authors: Packard Mary J. , Packard Gary C. , Miller Jeffrey D. , Jones Menna E. , Gutzke William H. N. 
Published: June 2005

AbstractEmbryos of the agamid lizard Amphibolurus barbatus are at developmental stage 29 of Dufaure and Hubert at the time of oviposition. Mobilization of calcium and other nutrients from the yolk proceeds slowly for the first half of incubation, during which time embryonic growth also proceeds slowly. During the second half of incubation, however, embryos withdraw calcium and other nutrients from the yolk very rapidly, and growth rates are correspondingly high. Approximately 60% of the calcium used by developing embryos is obtained from the yolk, but fully 40% of their requirement is met by calcium mobilized from the eggshell. Very little calcium remains in residual yolk of hatchlings, so this yolk must be used in maintenance metabolism rather than in growth of neonates. No dichotomy exists among oviparous, amniotic vertebrates with respect to sources of calcium used by developing embryos, but one does exist with respect to patterns of mobilization of this element. Whereas calcium is extracted from yolk of embryonic reptiles throughout incubation, it actually is deposited in yolk of embryonic birds after the midpoint in development.