bluuebunny/crossref_metadata_2025_split huggingface dataset:
Specificity of sperm‐zona interaction
Authors: Swenson Christine E. , Dunbar Bonnie S. 
Published: June 2005

AbstractThe specificity of early sperm‐zona interactions in vitro was studied using gametes from the mouse, rabbit, pig, and human. Mouse epididymal spermatozoa, capacitated in vitro, bound to the zonae of intact mouse oocytes and zona fragments removed mechanically from oocytes. When viewed with the scanning electron microscope (SEM), spermatozoa were found adherent more frequently to the external (cumulus) surface of the zonae than the internal (oocyte) surface. Noncapacitated mouse spermatozoa or spermatozoa incubated with zonae in the absence of external calcium did not bind to homologous zonae. By contrast, fresh, epididymal mouse spermatozoa and mouse spermatozoa capacitated in vitro appeared to attach equally well to both surfaces of zonae and zona fragments from rabbit and pig oocytes. Rabbit spermatozoa “capacitated” in vivo as well as noncapacitated rabbit spermatozoa, attached rapidly to both inner and outer surfaces of zonae from rabbit, mouse, and pig oocytes. This reaction was not dependent on external calcium. Human spermatozoa did not display any tendency to adhere to zonae from the rabbit, mouse, or pig. The results of these studies suggest that spermatozoa can associate with zona in a nonspecific as well as a specific manner. The use of heterologous systems in addition to homologous systems in sperm binding assays may be useful in distinguishing these two types of interaction.
Motor program of an intersegmental reflex in crayfish
Authors: Page Charles H. , Jones Kenneth A. 
Published: June 2005

AbstractFlexion of a merocarpal joint of a single leg initiates a discharge of the efferent neurons that produces postural abdominal extension in the crayfish. This intersegmental reflex is characterized by the excitation of those efferents whose effects are synergistic to extension, and the incomplete suppression of those efferents that are extensor antagonists. Comparison of the latencies and discharge patterns that are generated in response to leg flexion with those produced during “command fiber” stimulation suggests that this intersegmental reflex is mediated by the activation of more than one “command fiber” interneuron.
Fish erythrocytes are bicarbonate permeable: Problems with determining carbonic anhydrase activity using the modified boat technique
Authors: Heming T. A. , Randall D. J. 
Published: June 2005

AbstractEffects of foaming agents (blood plasma, bovine serum albumin, polyvinyl‐pyrrolidinone) and defoaming agents (octanol, No‐foam) on manometric determination of carbonic anhydrase activity in intact erythrocytes of fish were examined. Foaming agents abolished the activity of red cells. Defoaming agents increased the activity and negated any differences in carbonic anhydrase activity between whole blood (red cells in plasma) and “Cortland” blood (red cells in saline). It is concluded that effects of plasma on the carbonic anhydrase activity of intact erythrocytes of fish measured using the modified boat technique are largely non‐specific and related to reagent foaming during mixing, rather than to the action of a specific enzyme inhibitor.
Regeneration of transplanted chelae in two species of fiddler crabs (Uca pugilator and Uca pugnax)
Authors: Trinkaus‐Randall V. 
Published: June 2005

AbstractThe extensor muscle and chela of unoperated and transplanted regenerated limbs from two species of Uca were examined to test the theory of neurotrophic control on crustacean muscle. Initially, tuberculation patterns, sensory hair number, and claw shape of the transplanted regenerated limb resembled those of the donor. Sarcomere lengths were donorlike except when the transplant was from male to female. Eventually the transplanted regenerated limb acquired some recipientlike features, although the claw shape and sarcomere length measurements of secondary regenerates resembled those of the donor. Because of these findings, it is no longer possible to hypothesize that innervation alone controls the growth and differentiation of muscle.
Development of a latex‐conjugated immunocytological marker for scanning electron microscopic analysis of quail–chick chimeras
Authors: Meier Stephen , Drake Christopher 
Published: June 2005

AbstractQuail–chick chimeras are created by transplanting pieces of quail tissue to chick. We have used antibodies combined with a cell surface marking technique [modified after Molday et al.('75)], to facilitate scanning electron microscopic (SEM) identification of quail cells in such chimeras. First, antibodies to quail RBCs were raised in rabbits by intravenous injection. Rabbit anti‐quail RBC serum was precipitated by ammonium sulfate, purified by DEAE chromatography, and cross‐absorbed with chicken RBCs. Second, sheep anti‐rabbit IgG was purchased commercially and further purified by affinity chromatography. Third, 900‐Å‐diameter latex beads were synthesized by aqueous emulsion copolymerization of methacrylates. Spheres were bound with diaminoheptane to create an extension arm which was further derivatized in a two‐step glutaraldehyde procedure. Purified sheep IgG was bound to the aldehyde‐activated spheres, with uncoupled sheep IgG removed by sucrose density centrifugation. To test the marker, rabbit anti‐quail IgG was added to 1% diluted quail RBCs. After washing, sheep anti‐rabbit IgG bound spheres were introduced. Washed cells were fixed in one‐half strength Karnovsky's and processed for SEM. Quail RBCs were uniformly decorated with beads, containing 2,000 beads per cell. Similarly treated chick RBCs show no binding to beads. Likewise, quail RBCs not pre‐treated with the rabbit IgG do not bind beads. Prefixed quail RBCs still bind latex‐conjugated beads, although at somewhat reduced levels. When mixtures of quail and chick RBCs were processed for identification: (1) sphere labeling was an “all or none” phenomenon; (2) the proportion of bead‐decorated cells observable in the SEM was the same as the proportion of quail RBCs provided in the initial mix; and (3) morphologically distinguishable embryonic chick RBCs did not label whereas under the same conditions, quail RBCs do. We further demonstrate that rabbit antibodies prepared by injection of stage 4 quail primitive streaks can be used to specifically label quail epiblast and mesoblast cells, providing markers for at least two germ layers. It is now possible to combine grafting techniques of known success, with SEM analysis of the chimera.
Edema formation and impaired O2 transfer in ringer‐perfused gills of the eel, Anguilla australis
Authors: Ellis A. G. , Smith D. G. 
Published: June 2005

AbstractIsolated gills of the eel (Anguilla australis) were perfused with various solutions and subsequently examined using light or scanning electron microscopy. Oxygen transfer was measured in some perfusions. Ringer perfusion impaired O2 transfer and caused irreversible structural damage to the gills. Severe edema was consistently observed as a massive enlargement of the secondary lamellar subepithelial space. Addition of plasma protein substitutes (1–8% polyvinylpyrrolidone; 2–3% dextran) to Ringer perfusates failed to prevent edema, even when used in combination with 0.2% bovine serum albumin. Perfusion with fresh mammalian blood or plasma for up to 30 min did not cause edema, plasma perfusion significantly improving O2 transfer.Unless autologous blood or plasma is available, mammalian plasma is the most suitable perfusate for exchange studies in fish gills.As yet unidentified proteins in plasma probably reduce the pore dimensions of the pillar cell flanges, thereby reducing colloid loss from the vascular space.
The blockade of pigment displacement in swordtail erythrophores by microinjection of antiactin antibody
Authors: Akiyama Toyoko , Matsumoto Jiro 
Published: June 2005

AbstractWhen antiactin antibody produced against carp skeletal muscle actins was microinjected into monolayer‐cultured swordtail erythrophores, pigment displacement was almost completely blocked. Moreover, the injected antibody was equally effective at blocking the aggregation of dispersed pigment and the dispersion of aggregated pigment. If antibody saturated with carp actins was microinjected, no such blockade occurred.Microinjection of phalloidin or DNase I into these cells brought about an incomplete inhibition of their pigment displacement. These two drugs tended to inhibit pigment dispersion more than aggregation, suggesting that actins are differently involved in the two phases of pigment movement. The results all indicate that actins are functional elements in the pigment displacement of swordtail erythrophores, and that G‐F transformations of these molecules play little or no role in pigment aggregation, but are implicated in some way in dispersion.
Development of peroxisomes in amphibians. III. Study on liver, kidney, and intestine during thyroxine‐induced metamorphosis
Authors: Dauça M. , Calvert R. , Menard D. , Hugon J. S. , Hourdry J. 
Published: June 2005

AbstractThis investigation was undertaken to study the ontogeny of hepatic, renal, and intestinal peroxisomes and/or microperoxisomes during thyroxine‐induced anuran metamorphosis. Catalase activity was localized cytochemically after incubation in DAB medium, and studied biochemically by a spectrophotometric method. Our morphological and biochemical investigations suggest the formation of a new population of peroxisomes during the hormonal treatment. This is obvious especially for microperoxisomes of the intestinal epithelium since the larval tissue is completely replaced by a new layer during thyroxine‐induced metamorphosis. For the peroxisomes of hepatocytes and kidney proximal tubule cells, our assumption is based on the following observations: (1) The number of peroxisomes increases in liver and kidney during thyroxine treatment; (2) this proliferation is accompanied by an enlargement of renal peroxisomes; and (3) 16 days after the beginning of the hormonal treatment, 5.4‐ and 2.4‐fold increases are found for the specific activities of hepatic and renal catalase, respectively. A temporal coordination exists between the structure and the metabolism of peroxisomes and mitochondria during thyroxine‐induced metamorphosis.
Pattern of growth in a temperate zone anuran (Bufo viridis Laur.)
Authors: Jørgensen C. Barker 
Published: June 2005

AbstractGrowth in body length and mass was followed in 1‐year‐old toads Bufo viridis collected early August, kept in the laboratory at 20°C, and fed meal worms ad libitum for 24 h once or twice a week. The nutritional condition of the toads was evaluated from the condition index (CI) = 1,000 × body mass (g) × length (cm)−3. The rates of growth in length were high initially, in August and September, and then dropped to insignificant levels. Growth was abruptly resumed in spring, and growth rates were high in March to May. The CI increased to a maximum in September. During the period of growth stagnation it tended to decrease. After growth was resumed in spring, the CI again increased, but with a delay. During autumn the toads allocated food for lean growth and fattening, and eventually reduced feeding and growth, according to the pattern typical of toads in nature. This pattern was not affected by artificial long days. It is thus suggested that 1‐year‐old Bufo viridis exhibit inherent control of the behavioral and physiological mechanisms that prepare the organism for hibernation. During the spring period of growth the toads were out of phase with toads in nature. However, the synchrony of growth among the experimental toads continued. It is suggested that the second growth period also may represent an inherent functional pattern that was prematurely initiated under the conditions of the experiment.
Sperm reception by an egg microvillus in the polychaete, Tylorrhynchus heterochaetus
Authors: Sato Masanori , Osanai Kenzi 
Published: June 2005

AbstractA fine‐structure study of sperm‐egg interactions during normal fertilization in the polychaete Tylorrhynchus heterochaetus was carried out. Sperm initiated an acrosome reaction on the outermost layer of the chorion, which consisted of four layers. After the acrosomal vesicle opened, the subacrosomal space expanded to become a lobular acrosomal process, the frontal margin of which penetrated the first and second layers of the chorion and adhered to the third layer. The process did not penetrate the third and fourth layers. Within 1 min of insemination the acrosomal process of the fertilizing spermatozoon fused with a microvillus projecting from the egg through the chorion. The microvillus thickened and developed into a sperm penetration cone. The sperm nucleus entered the egg cortex through this cone 20–25 min after insemination. The result shows that the tips of egg microvilli are sites for sperm reception.
Mollusk shell organic matrix: Fourier transform infrared study of the acidic macromolecules
Authors: Worms Daniele , Weiner Stephen 
Published: June 2005

AbstractIon‐binding ligands and the conformations of some of the acidic matrix macromolecules present in the shells of a gastroped, a bivalve, and a cephalopod, are investigated in vitro by Fourier transform infrared spectroscopy. The complex assemblage of matrix constituents present in the EDTA‐soluble fraction is first separated into two quite different classes of macromolecules by a reversed‐phase chromatographic procedure. Infrared spectra indicate that the constituents of one class, which are proteins rich in aspartic acid, adopt the β‐sheet conformation upon binding calcium to the protein carboxylate groups. The second class of matrix constituents contains proteins rich in serine that appear to be associated with relatively large amounts of polysaccharide. They also bind calcium and upon doing so undergo a conformational change.
The influence of tunichrome and other reducing compounds on tunic and fin formation in embryonic Ascidia callosa Stimpson
Authors: Robinson William E. , Kustin Kenneth , Cloney Richard A. 
Published: June 2005

AbstractTunic in 46‐hr‐old Ascidia callosa larvae reared from dechorionated neurulae is either markedly reduced in thickness or absent altogether. The epidermis is fragile and cuticular fins fail to develop. Dechorionated neurulae treated with tunichrome and other reducing compounds (e.g., glutathione, ascorbate) show an enhancement in tunic formation and rudimentary fin development. UV absorbance spectra of extracts from unfertilized eggs, late tail‐bud embryos, and tadpole larvae indicate that tunichrome may be present in all developmental stages. Experiments with neurulae in which the chorion was punctured with tungsten needles but not removed signify that the test cells are the most likely source of tunichrome. Results are consistent with the hypothesis that tunichrome is involved in the natural processes of tunic morphogenesis in ascidian embryos.
Glycosaminoglycans stimulate the acrosome reaction of previously capacitated hamster sperm
Authors: Meizel Stanley , Turner Kenneth O. 
Published: June 2005

AbstractThe glycosaminoglycans (GAGs) hyaluronic acid and heparin were added (10 μg and 100 μg/ml to golden hamster sperm suspensions previously incubated for 4.5 h under capacitating conditions. After additions, sperm were incubated for 5–15 min and acrosome reactions (AR) assayed in motile sperm by phase contrast microscopy. Hyaluronic acid and heparin significantly stimulated AR over control levels. Hyaluronic acid did not stimulate AR 15 min after addition to sperm previously incubated for only 2.5 h. Pre‐incubation of hyaluronic acid with streptomyces hyaluronidase destroyed the ability of that GAG to stimulate the AR. These results indicate that GAGs (at least one of which, hyaluronic acid, is present in the oocyte cumulus oophorous) can rapidly stimulate the acrosome reaction in motile previously capacitated hamster sperm.
Urates and allantoic regulation in embryonic Japanese quail, Coturnix coturnix japonica
Authors: McNabb Roger A. 
Published: June 2005

AbstractDuring embryonic development, allantoic fluid represents the shifting balance between renal excretion and reabsorption by chorioallantoic membranes. Allantoic contents of Na+, K+, Cl−, urate, pH, and water were followed over days 10–15 of the 16 day incubation. Water volume remained near 0.9 ml until day 13, then declined very rapidly. The pH declined more steadily, from 8 to 5.5. Contents of Na+ and Cl− fell regularly to final values 80–88% below day 10. The K+ content changed differently and nearly doubled by day 13 but returned to day 10 values at the end. Urate content rose until day 13, then fell suddenly to low levels. This was due to the abrupt precipitation of most urate into masses not sampled by our method, so that after day 13, urate was underestimated (probably by 90–96%). Ion binding by urates was low (about 3% of Na+ and Cl−, 10% of K+) and appeared to be nonspecific. The underestimate of urate contents means, however, that in late incubation about one third of allantoic Na+ and 65–70% of K+ and Cl− are bound to precipitated urate and do not appear in balance sheets of allantoic ions. These precipitated ions account for the significant amounts of Na+ and K+ that remain in the allantoic remnant, left in the eggshell after hatching, but whose presence is not predicted by analysis of allantoic fluid.
Matrix proteins of the teeth of the sea urchin Lytechinus variegatus
Authors: Veis Deborah J. , Albinger Todd M. , Clohisy John , Rahima Mohammed , Sabsay Boris , Veis Arthur 
Published: June 2005

AbstractThe teeth of the sea urchin Lytechinus variegatus grow continuously. The mineral phase, a high magnesium calcite, grows into single crystals within numerous compartments bounded by an organic matrix deposited by the odontoblasts. Electron microscopic examination of glutaraldehyde‐fixed Ethylene Diamine Tetra acetic acid (EDTA) demineralized teeth shows the compartment walls to be organized from multiple layers of cell membrane which might contain cytoplasmic protein inclusions. Proteins extracted during demineralization of unfixed teeth were examined by gel electrophoresis, high performance liquid chromatography, and amino acid analysis. The tooth proteins were acidic, they contained phosphoserine, and they were rich in aspartic acid. By contrast, the proteins of similarly extracted mineralized Aristotle's lantern skeletal elements were nonphosphorylated and were rich in glutamic acid. Vertebrate tooth and bone matrix proteins show similar differences. Surprisingly, an antibody to the principle rat incisor phosphoprotein showed a significant cross‐reactivity with the urchin tooth protein, by dot‐blot and enzyme‐linked immunosorbent assay procedures. Thus, the urchin tooth proteins contain epitope regions similar to those which are phenotypic markers of vertebrate odontoblasts. Whether this is an expression of convergent or divergent evolutionary processes, it is likely that the matrix proteins play a similar role in matrix mineralization. The sea urchin tooth may thus be an excellent model for the study of odontoblast‐mediated mineral–matrix relationships.
Experimental analysis of cytokinesis in Amoeba proteus
Authors: Rappaport R. , Rappaport Barbara N. 
Published: June 2005

AbstractThe purpose of this investigation was to determine whether the mechanism of cytokinesis in Amoeba proteus depends primarily upon locomotion and traction (fission) or whether the mechanism resembles that of metazoan cells. Cytokinesis is unaffected by measures that prevent attachment of the organism to the substratum. Amoebae divided when they were (1) detached from the substratum and repeatedly shifted, (2) suspended in fluid medium by one pole, (3) placed on an oil–water interface, and (4) transferred to de‐ionized water so that attachment was prevented. Unilateral furrows formed when the mitotic apparatus was shifted to an eccentric position. Enucleated portions of cytoplasm containing part of the equatorial region were amputated at different phases of the mitotic cycle. Enucleated pieces amputated at later prophase never formed permanent furrows, although 3 of 17 showed furrowlike activity. Of 26 enucleated pieces amputated at metaphase, 23 showed division activity. Of these, 21 formed temporary furrows and 2 completed division.Although attachment and locomotion may be normal during division of A. proteus, they were not essential for cytokinesis, and their involvement is restricted to the final parting of the cytoplasmic thread that connects the daughter cells. The mechanism responsible for the greater part of the constriction activity in the furrow region resembles that of metazoan cells in that it is localized in the surface and it is established by the mitotic apparatus.
Development of the prepupal Verson's gland of the tobacco hornworm, Manduca sexta, and its hormonal control
Authors: Lane Sandra , Riddiford Lynn M. , Truman James W. , Conitz Jan 
Published: June 2005

AbstractThe segmentally arranged Verson's glands are epidermal derivatives comprised of three cells: the duct, saccule, and secretory cells. The development of these glands was followed through the 5th instar and larvalpupal transition of Manduca sexta. The glands are relatively small during the feeding stage, begin to grow at wandering, and undergo about a 50‐fold increase in size during the prepupal period. The increase in size is due mainly to the hypertrophy of the secretory cell which synthesizes a heterogeneous set of proteinaceous secretory products. Three prominent 11 to 12 kiloDalton (kD) polypeptides are made by the pharate fifth larval gland, whereas the pupal gland produces polypeptides ranging from 14 to 75 kD with a major complex at 30 to 34 kD. The secretory product is poured out onto the surface of the new cuticle at the time of ecdysis and contains all of the major proteins detected in extracts of the whole gland. The accumulation of secretory products by the gland occurs during the prepupal peak of ecdysteroid and is blocked if this rise is prevented by abdominal isolation. Infusion of 30 μg 20‐hydroxyecdysone (20‐HE) into such isolated abdomens caused synthesis of the pupal products. Treatment with the juvenile hormone mimic, methoprene, during the fifth instar showed that the commitment of the glands to produce the pupal proteins is independent of and occurs before the overlying epidermis becomes committed to make pupal cuticle.
Microcythemia from anemic hypoxia and normal erythropoiesis in the newt
Authors: Frangioni Giuliano , Borgioli Gianfranco , Martini Remo 
Published: June 2005

AbstractSpecimens of the newt, Triturus cristatus carnifex (Laurenti), rendered totally anemic, restore erythron by cyclic waves of erythropoietic activity that alternate with intervals of stasis. Hemolysis is obtained by administering 25 mg/liter of acetylphenylhydrazine in the breeding water for 36 h. The first cycle of erythropoietic activity produces microcytes, which have completely differentiated by 8 weeks after treatment. However, if the animals are raised in a hyperbaric chamber at a pressure of 1.5 atmospheres, in order to compensate for hypoxia, normocytes are produced. In both cases the hematocrit and hematic concentration of hemoglobin reach analogous values, so microcythemia appears to be the only effect of hypoxia. The hemoglobin, hematocrit values, and normocyte counts in hyperbaric animals are about onehalf those of the controls newts. These data, together with those on the life span of red blood cells (RBC) and time span between two successive erythropoietic cycles (2 months and 1 month, respectively), indicate that the newts normally keep only two sets (one new, one old) of RBC in circulation, whose approximate parameters can be defined as RBC count: 60,000/mm3, hematocrit: 17%, and hemoglobin: 5.4 g/100 ml.