bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of avidin‐interacting proteins in Spisula oocytes: Correlation with germinal vesicle breakdown
Authors: Haneji Tatsuji , Koide Samuel S. 
Published: June 2005

AbstractPeroxidase‐conjugated avidin was used to determine the presence of avidin‐interacting proteins in Spisula oocytes. By a transblot method, avidin‐peroxidase conjugate interacted with the two proteins with estimated molecular weights of 70,000 and 118,000 in the cytosolic fraction of Spisula oocyte. The reaction with the same proteins in the particulate fraction was considerably reduced. None or weak reaction occurred with proteins prepared from Spisula muscle, sperm, and body fluid. With Arbacia oocytes or hen egg‐yolk and egg‐white proteins, the reaction was minimal or none, respectively. When the avidin‐peroxidase conjugate was preincubated with biotin, its stain‐ ing activity was lost, suggesting that the interacting proteins probably contain biotin.To determine whether avidin‐interacting proteins are involved in oocyte maturation, Spisula oocytes were treated with 50 mM KCl or 5 μM serotonin to induce germinal vesicle breakdown (GVBD). The staining reaction with the 70,000‐ and 118,000‐dalton proteins in the samples prepared from oocytes treated with KCl or serotonin was greatly intensified and an additional protein with an estimated molecular weight of 220,000 was stained. The occurrence of avidin‐interacting proteins in Spisula oocytes was further verified by the positive staining reaction with a cytochemical method using fluorescein isothiocyanate (FITC)‐conjugated avidin.
Hemocyanin structure changes during early development of the crab Cancer productus
Authors: Wache Susanne , Terwilliger Nora B. , Terwilliger Robert C. 
Published: June 2005

AbstractHemocyanin is present in oocytes and embryos of the brachyuran crab Cancer productus. Oocyte hemocyanin, like adult crab hemocyanin, exists as two hexamer (25S) and single hexamer (16S) aggregates. The two hexamer molecule is composed of at least four electrophoretically distinct subunits. The electrophoretic properties of oocyte hemocyanin subunits are indistinguishable from those of the corresponding adult hemocyanin. Evidence is presented that oocytes could take up maternal hemocyanin through endocytosis. Hemocyanin present in the developing embryo also exists as two hexamer and hexamer aggregates. However, the embryo two hexamer hemocyanin shows an electrophoretic pattern of subunits different from that of maternal or oocyte two hexamer hemocyanin. These data, together with previous studies on other species of decapod crustaceans, indicate that hemocyanin different from the adult molecule is produced after fertilization of the egg.
Patterns of cholinesterase staining during neural crest cell morphogenesis in mouse and chick embryos
Authors: Martins‐Green M. , Erickson C. A. 
Published: June 2005

AbstractCholinesterase (ChE) activity has been reported previously in nonneuronal tissues of a variety of avian and mammalian embryos. We report here a comparison study of ChE staining in chick and mouse embryos. Transmission electron microscopy was used to study the distribution of this activity in neuroepithelial, neural crest, somite, and ectodermal cells. Our cytochemical studies show that the distribution of nonspecific ChE staining in these tissues during neurulation is similar in the two species but that acetylcholinesterase (AChE) staining, previously shown to be intense in the chick, is absent in the mouse; the only cells showing the presence of this enzyme at these stages of development in mouse are blood cells. However, AChE staining does appear later in the brain, in neural tissues derived from the neural crest and, perhaps, in some migratory neural crest cells. The differences between AChE distribution in these two species (and that reported previously in the rabbit) indicate that the timing of first appearance of AChE is unrelated to neuroepithelial morphogenesis or to neural crest cell motility. The correlation between nonspecific cholinesterases and morphogenetic movements, however, is supported by these studies.
Reversing cytoplasmic flow in nucleated, constricted sand dollar eggs
Authors: Rappaport R. , Rappaport Barbara N. 
Published: June 2005

AbstractThe purpose of this investigation was to study the nature of the immediate response of the surface to the mitotic apparatus in sand dollar (Echinarachnius parma) eggs. The normal geometrical relationship was changed by snaring fertilized eggs between opposed, overlapping hooks and constricting the eggs to reshape them into two partial spheres joined by a constricted neck about 27 μm in diameter. When both asters of the mitotic apparatus lay on the same side of the constriction, cytoplasm flowed out of the nucleated part across the constriction, beginning about 30 min before anticipated cleavage time. After the asters moved across the constriction, the direction reversed, and reversal usually occurred several times before cleavage (n = 18). The average time between beginning of flow in one direction and beginning of flow in the opposite direction was 7.7 min (n = 23). Cells were bisected and constricted to determine the role of the mitotic apparatus. Bisected cells with two asters behaved like constricted normal cells (n = 15). Cells with no mitotic apparatus developed no cytoplasmic flow (n = 11). In cells with one aster, flow most often occurred within ten min of anticipated cleavage time (n = 14). When whole constricted eggs were treated with Cytochalasin B at the minimum concentration that blocks cleavage in normal eggs (3 μg/ml), neither cytoplasmic flow nor cleavage occurred, although the mitotic apparatus developed normally.Cytoplasmic flow in constricted eggs in cleavage stages requires asters and functional actin‐associated cytoskeleton. The results suggest that the asters cause an increase in tension in nearby surfaces.
Fertilization of zona‐drilled mouse oocytes treated with a monoclonal antibody to the zona glycoprotein, ZP3
Authors: Conover J. C. , Gwatkin R. B. L. 
Published: June 2005

AbstractOpening a small aperture in the zona pellucida of mouse oocytes by using micromanipulation and a stream of acidified Tyrode's solution (zona drilling) improved the efficiency of in vitro fertilization at low sperm concentrations without adversely affecting development to the blastocyst stage. Zona drilling also permitted in vitro fertilization and development when sperm penetration through the zona was blocked by a monoclonal antibody to the protein core of the zona glycoprotein, ZP3. These results provide a direct demonstration that sperm entry occurs through the aperture and also suggest that zona drilling of human oocytes may offer a therapeutic approach when autoantibodies to the zona pellucida are suspected as a cause of infertility.
Antisera probes to an atypical pseudocholinesterase from surgeonfish reveal immunochemical variability and tissue‐specific molecular polymorphism
Authors: Leibel Wayne S. 
Published: June 2005

AbstractPolyclonal antisera were raised in rabbits against the purified sialated, presumedglobular tetrameric pseudocholinesterase (pseudo‐ChE) from surgeonfish (Leibel: Journal of Experimental Zoology 1988b) and against commercially obtained Electrophorus electroplax AChE. The resulting antisera probes were absolutely specific for their respective antigens and failed to titrate ChE activities heterologously. However, each antisera probe did crossreact with its other respective globular and asymmetric aggregational isozymes. The resultant specific probes were then used to examine interspecific evolutionary conservation of the two ChE activities and, in conjunction with velocity sedimentation analysis and differential paraoxon inhibition, the tissue distribution and molecular polymorphism of these same two enzyme systems in surgeonfish.These experiments suggest the tight evolutionary conservation of AChE in contrast to the apparent high variability of pseudo‐ChE amongst the wide range of teleost fishes tested. The native atypical pseudo‐ChE was shown to exist, like AChE, as a series of sialated and asialated globular and asymmetric aggregational isozymes whose relative distribution exhibits marked tissue specificity. The extremely high levels of pseudo‐ChE characteristic of white skeletal (epaxial) muscle, in particular, was conspicuous, and its occurrence in the sarcolemma is discussed in the context of its possible function and in relation to the apparent lack of evolutionary conservation amongst marine teleosts.
Sites and trend of erythropoiesis in anemic, normal, and splenectomized newts
Authors: Frangioni Giuliano , Borgioli Gianfranco 
Published: June 2005

AbstractNewts, Triturus cristatus carnifex (Laurenti), were anesthetized by submersion in 2% chlorbutol in tap water for 15 min, splenectomized and then rendered totally anemic two months later by treatment with acetylphenylhydrazine (APH) diluted in their tanks (25 mg/liter for 36 h, changing the solution every 12 h). In the 14 weeks following hemolysis, erythron restoration occurred with the same intermittence as it did in whole animals rendered anemic by APH treatment: Beginning the second week the red blood cell count progressively increases for about one month, followed by a period of stasis which lasts about three weeks, then by a new increase, and then by a final period of stasis. Histological examination shows that erythropoietic activity occurs partly in the circulating blood and partly in erythroblasts nestled in the crypts between the muscular trabeculae of the ventricle as well as in the atrial walls. These cells, which are not part of the freely circulating elements in the blood stream, become very abundant in both whole and splenectomized anemic newts but are also present in normal animals. Newts, thus, have three sites for erythropoiesis: the spleen, the blood stream, and the heart. The other components compensate for the elimination of the spleen without determining any lack of, or delay in, erythropoietic response.
Autoreactive blood cells and programmed cell death in growth and development of protochordates
Authors: Harp James A. , Tsuchida Craig B. , Weissman Irving L. , Scofield Virginia L. 
Published: June 2005

AbstractThe tunicate Botryllus is a marine protochordate whose clonal colonies undergo regulated natural transplantations when they come into contact in nature. The outcome of these transplantations (fusion or rejection) is controlled by genes of a highly polymorphic histocompatibility system that resembles in many respects the mammalian major histocompatibility complex (MHC). While fusion or rejection reactions are often completed within 24 hr after transplantation, resorption of one partner of a pair of fused semiallogeneic colonies may occur days to weeks after initial contact. The latter process is similar to the degeneration of old individuals, or zooids, that precedes maturation of each new generation of asexual buds. Here we describe comparisons of in vitro reactions of (a) mixtures of cells from allogeneic animals and (b) cells taken from animals at the zooid‐resorption (“takeover”) stage of colony development. In vitro autoreactivity of cells from resorbing colonies may reflect in vivo responses to senescent cells, which in turn may be related to allorecognition events that govern fusion or rejection between colonies.
Immediate response to repeated capture and handling of wild impala
Authors: Hattingh J. , Pitts N. I. , Ganhao M. F. 
Published: June 2005

AbstractThe composition of blood from veld and boma (enclosure)‐kept impala, obtained immediately after the animals were manually restrained, was compared to control values. Statistically significant differences existed between the values for hematocrit, lactate, glucose, and osmolarity of veld and boma‐kept animals compared to control data. Cortisol values were significantly greater (P < .05) in boma‐kept animals (93 ± 21 nmol/liter) but not in veld impala (11 ± 3 nmol/liter). It is suggested that the high cortisol and other values measured in boma‐kept impala were due to an anticipatory conditioned response in these animals which occurred prior to them actually being caught. Repeated capture and handling, over a period of several months, of boma‐kept impala resulted in statistically insignificant decreases in the mean values of several variables. Although this is indicative of adaptation it is doubtful whether the animals would ever fully adapt to the procedures involved.
Catecholamine metabolism by the perfused rainbow trout gill
Authors: Colletti A. E. , Olson K. R. 
Published: June 2005

AbstractThe trout gill has the capacity to influence general adrenergic activity through extraction and metabolism of circulating catecholamines (CA); (Nekvasil and Olson, Am. J. Physiol., 1986, 250:R526–R531). To further examine the metabolic process, isolated gills were perfused with 10−8 M and 10−6 M norepinephrine (NEPI) or epinephrine (EPI) and effluent from the arterioarterial (AA) and arteriovenous (AV) pathways analyzed by high pressure liquid chromatography with electrochemical detection (HPLC‐EC). After 20 minutes of continuous 10−6 M NEPI perfusion, metabolites accounted for 70% and 96% of the total amines recovered in the AA and AV effluents, respectively. After 20 minutes of 10−6 M EPI perfusion, 60% and 94% of the amines in the AA and AV effluents, respectively, were metabolites. Similar results were seen during perfusion with 10−8 M CAs. Dihydroxymandelic acid (DHMA) and vanillylamandelic acid (VMA) were the major metabolites identified in gill effluent. Gills perfused with a bolus of 3H‐NEPI extracted 47% of the radiolabel. Continuous perfusion with 10−5 M cocaine or 10−5 M tyramine 30 minutes after the 3H‐NEPI pulse released 3H‐labeled and ‐unlabeled NEPI and metabolites into the AA effluent. Cocaine released more unmetabolized 3H‐NEPI than tyramine, whereas tyramine released more 3H‐labeled metabolites than cocaine. These studies indicate that the gill efficiently inactivates CAs through metabolism and that the major products formed are deaminated (DHMA) and deaminated:O‐methylated (VMA) metabolites. The gill is also able to remove NEPI from the perfusate and store it intact for up to 50 minutes. Branchial uptake of CAs in fish and pulmonary uptake of CAs in mammals appear to have basic similarities.
Effects of two juvenile hormone analogs (R‐20458, RO203600) and three juvenile hormones (JH 1, 2, and 3) on the number and distribution of sensilla on the seventh abdominal tergite in the male German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae)
Authors: Wheeler Christine M. , Gupta A. P. 
Published: June 2005

AbstractThree types of sensilla, s. chaetica B, s. trichoidea, and s. campaniformia were identified on the 7th abdominal tergite of JH‐JHA‐and acetone (control)‐treated adult male Blattella germanica by light and scanning electron microscopy. All contact chemoreceptors (s. chaetica B) and the majority of mechanoreceptors (s. trichoidea) surround the gland openings or cover the tergal modification, which indicates that contact chemoreception and mechanoreception are important in the tergal feeding stage of mating behavior. The numbers of all three types of sensilla were significantly reduced for all five treatments.
Modification of pyruvate kinase from the foot muscle of Patella caerulea (L) during anaerobiosis
Authors: Michaelidis B. , Gaitanaki C. , Beis Is. 
Published: June 2005

AbstractPyruvate kinase (PK) from the foot muscle of Patella carulea (L) is present as two variants. These variants are eluted by ion‐exchange chromatography from DEAE‐cellulose as peak I and peak II at different concentrations of KCl. Studies of their kinetic properties show that both variants of PK exhibit sigmoidal curves with respect to phosphoenolpyuvate (PEP), but the PK in peak I is more sensitive to the activation by PEP and fructose diphosphate (FDP) and less sensitive to inhibition by alanine, ATP, and H+ than the PK in peak II. The proportion of the two PK variants changes during anaerobiosis. The ratio of the number of units of enzyme in peak I to that in peak II increases up to the second hour and then decreases up to the eight hour of anaerobiosis. Studies on the electrophoretic mobility of these two variants on strips of cellulose acetate show that the less active from or peak II PK migrates more quickly toward the anode (Rf = 0.13) than the more active from or peak I PK (Rf = 0.07). Peak II PK, after treatment with alkaline phosphatase, exhibits kinetic properties and electrophoretic mobility quite similar to those of peak I PK. The above data suggest that the two variants of PK from the foot muscle of P. caerulea are interconvertible and the direction of the interconversion depends on the duration of anaerobiosis.
Secretion of proteins by cultured bovine oviducts collected from estrus through early diestrus
Authors: Malayer J. R. , Hansen P. J. , Buhi W. C. 
Published: June 2005

AbstractTo characterize in vitro protein secretion by the oviduct throughout early stages of the estrous cycle, 16 cows received a luteolytic dose of PGF2α and were randomly assigned to be killed on day (D) 0, 2, 5, or 8 after subsequent estrus. Explant cultures of oviducts (ampulla and isthmus) were incubated for 24 h at 39°C in a modified Eagle's minimal essential medium supplemented with 50 μCi L‐[4,5‐3H]leucine. Oviductal secretion of de novo synthesized protein measured by incorporation of [3H]leucine into nondialyzable radioactivity in culture supernatants was greatest at D 0 and declined thereafter. Incorporation of [3H]leucine into TCA‐precipitable macromolecules in tissue homogenates was also greatest at D 0. Analysis of culture supernatants by one‐dimensional polyacrylamide gel electrophoresis revealed four major bands of radiolabeled proteins at > 97 kDa, 85–97 kDa, 55 kDa, and 30 kDa. Analysis of individual polypeptides resolved by two‐dimensional polyacrylamide gel electrophoresis indicated that five of 32 individual polypeptides examined were secreted at significantly greater rates at estrus than at other times examined. One of these five polypeptides, a 97‐kDa peptide with an apparent pI of 5.0, was the major secretory product at estrus and accounted for 18% of total radioactivity recovered from two‐dimensional gels. Two of 32 polypeptides examined were secreted at significantly greater rates by explants of the oviduct contralateral to the side of ovulation. In summary, estrus is associated with an elevation in total protein secretion by the bovine oviduct. This increase is due to selective amplification of secretion of several but not all secretory proteins.
A staging system for mouse limb development
Authors: Wanek N. , Muneoka K. , Holler‐dinsmore G. , Burton R. , Bryant S. V. 
Published: June 2005

AbstractA series of 15 stages of development for the mouse limb bud have been defined, spanning the time from the first appearance of the limb bud to the completion of limb outgrowth. The stages are based on changes in the morphology of the limb in living preparations. The development and regression of the apical ectodermal ridge (AER) as well as the development of the skeletal structures are also described. This staging system has been developed in response to the need to standardize in situ experimental analyses of the mouse limb bud. Comparable stages of the commonly used chick wing and mouse whole embryo systems are presented.
Absence of an electrical block to polyspermy in the scaphopod mollusk Dentalium vulgare
Authors: Moreau M. , Guerrier P. , Dufresne L. 
Published: June 2005

AbstractWe investigated the electrical properties of the egg of the Scaphopod mollusk Dentalium vulgare during fertilization. Following fertilization in natural or artificial sea water, the membrane potential shifts from its resting level (−70, −80 mV) to recurring small depolarizations of 5–20 mV (minispikes). A classical fertilization potential of 60–80 mV amplitude may also occur. However, it does not represent an unescapable event and may even appear as late as 20–40 min after insemination, i.e., when sperm pronuclei are already formed in the egg. Even when it occurs early, and over a long duration, this response cannot block polyspermy, which also occurs after clamping the egg potential at positive or negative values. Moreover, similar responses may appear spontaneously, in the absence of insemination.In contrast, minispikes are only triggered by the spermatozoon and their amplitude depends on the external Na and Ca concentrations. Their number is the function of sperm density, but always appears in excess over the number of penetrated spermatozoa. Minispikes are not abolished by cytochalasin B (2 μg/ml), which greatly reduces the number of successful sperm penetrations. These data suggest that no voltage‐dependent mechanism limits sperm penetration in the plasma membrane of Dentalium eggs, and that minispikes may result from the opening of individual patches of channels, either triggered by each attached spermatozoon or recurrently stimulated, following sperm penetration.
A morphometric study of bone and tooth volumes in the pipid frog Xenopus laevis (Daudin), with comments on the importance of tooth resorption during normal tooth replacement
Authors: Shaw J. P. 
Published: June 2005

AbstractVolumetric estimations of teeth and bone on serial sections using a semiautomatic image analyzer indicate that, in the polyphyodont dentition of the pipid anuran Xenopus laevis (Daudin), the mean volume of the dentine composing the teeth is about 23.5% of the volume of the supporting maxillae and premaxillae. During tooth replacement, osteoclasts resorb up to 98% of the dentine. Teeth may be resorbed rather than shed in order to conserve tooth constituents because, if shedding of complete teeth did occur, a quantity of calcified tissue equal to perhaps 45 times the volume of the bone of the upper jaw might be lost over an animal's projected life span of about 13–15 years.
Cytogenetic analysis of ethanol‐induced parthenogenesis
Authors: O'Neill G. T. , Kaufman M. H. 
Published: June 2005

AbstractThe brief exposure of recently ovulated mouse oocytes to a dilute solution of ethanol in vitro for 1, 3, or 5 min induced a uniform high incidence of parthenogenetic activation. The majority of parthenogenones developed a single haploid pronucleus after the extrusion of a second polar body. The proportionate incidence of this parthenogenetic class was significantly reduced as the duration of ethanol exposure increased from 1 min to 5 min. There was a concomitant increase in the incidence of parthenogenones that developed two haploid pronuclei following failure of extrusion of the second polar body. Cytogenetic analysis of the ethanol‐induced single‐pronuclear haploid parthenogenones at metaphase of the first cleavage division clearly demonstrated that a significant proportion were aneuploid. The incidence of aneuploidy observed was directly related to the duration of ethanol exposure. G‐band analysis of the aneuploid metaphases revealed that the chromosomes were not randomly involved in the malsegregation events. This observation may be a reflection of the relationship of particular chromosomes to the meiotic spindle apparatus rather than on any specific property of the agent to which they were exposed. It is believed that ethanol disrupts the organisation of cytoskeletal elements and, in particular, interferes with the processes of chromosome segregation at the second meiotic division.