bluuebunny/crossref_metadata_2025_split huggingface dataset:
Taurine maintains and stimulates motility of hamster sperm during capacitation in vitro
Authors: Mrsny Randall J. , Waxman Lloyd , Meizel Stanley 
Published: June 2005

AbstractIt is known that hamster sperm require an unidentified low molecular weight “factor” found in several cells and tissue types in order to remain strongly motile during in vitro capacitation. The β‐amino acid taurine (2‐aminoethane sulfonic acid) is present in a partially purified “factor” from bovine adrenal glands and can substitute for that “factor” in maintaining and stimulating hamster sperm motility. Incubation of washed hamster sperm with bovine serum albumin and 2 × 10−3 to 2 × 10−5M taurine for periods of approximately 5 hr. resulted in a higher number of strongly motile sperm compared to controls in the absence of exogenous taurine. Incubation of sperm with (‐)epinephrine in the absence of taurine resulted in nearly all sperm becoming immotile. Activation (whiplash flagellar movement characteristic of capacitated hamster sperm) did not occur in the absence of taurine, but high percentages of activation occurred in the presence of 2 × 10−3, 2−10−4 and 2 × 10−5M taurine. Acrosome reactions occurred in the presence of taurine, even in the absence of (‐)‐epinephrine. However, (‐)‐epinephrine, previously shown to stimulate activation and acrosome reactions, was required for the maximum number of the latter. These results suggest that in addition to its importance for motility taurine might stimulate capacitation. The mechanism through which taurine supports and stimulates motility is not yet known, but its use results in the first relatively “defined” in vitro capacitation medium for hamster sperm.
Reversal of polarity in ciliated cells of the isolated sea urchin pluteus gut
Authors: Amemiya Shonan , Akasaka Kohji , Terayama Hiroshi 
Published: June 2005

AbstractGuts isolated from pluteus embryos of Hemicentrotus pulcherrimus were observed by scanning electron microscopy in the course of 24 h culturing in normal sea water. They showed marked morphological changes such as disappearance of the regional features, closure of the endings (oral and anal), and reappearance of the regional features corresponding to the stomach and esophagus (but lacking the intestinal and pharyngeal regions). In parallel to the above morphological changes, the cilia usually associated with the interior surface of isolated guts disappeared and new cilia appeared on the exterior surface of the isolated guts, causing the isolated guts swim around by the end of the culture period. These results suggest the reversion of cellular polarity in the isolated gut wall in response to the environmental change.
Osmotic and cell volume regulation in the goby, Gillichthys mirabilis
Authors: Loretz Christopher A. 
Published: June 2005

AbstractThe gobiid teleost Gillichthys mirabilis acclimated successfully to external environments ranging from 100% seawater to freshwater. Plasma composition and cell volume are regulated in both hypo‐ and hyperosmotic environments. Significant declines in plasma electrolyte concentrations and increase in intracellular hydration were observed only in freshwater‐acclimated fish. Cell volume regulation in hypoosmotic media appears to result from the loss of intracellular solutes. Hypophysectomy seriously impaired regulation of plasma composition and cell volume in dilute external environments, a finding consistent with the known role of prolactin in promoting freshwater survival of teleosts.
Ecdysteroid levels and pupariation in drosophila melanogaster
Authors: Berreur P. , Porcheron P. , Berreur‐Bonnenfant J. , Simpson P. 
Published: June 2005

AbstractEcdysteroid titers measured in the haemolymph of third instar larvae of Drosophila revealed the existence of a small peak (40 ng/ml) preceding the major peak at pupariation. Under experimental conditions of delayed pupariation, the release of both ecdysteroid peaks is retarded. The possibility that the earlier pulse is implicated in the programming of the time of pupariation is raised.
An acrosome reaction in natantian sperm
Authors: Yudin Ashley I. , Clark Wallis H. , Kleve Maurice G. 
Published: June 2005

AbstractSperm of the natantian Sicyonia ingentis are highly polarized with a conical cap and single spike extending from a spherical main body. Previous studies have shown the acrosome consists of two periodic acid‐Schiff‐positive cap components and the spike. During sperm‐egg interaction the spike is lost and the cell dehisces to expose the components of the acrosome, which lie directly apposed to the egg surface. Treatment of sperm with ionophore A23187 initiates this reaction and facilitates sequencing of the reaction. The ionophore‐induced reaction begins with retraction of the spike and concomitant swelling of the cap. These events result in the opening of the cap and exposure of the internal acrosomal components which become the new anterior surface of the sperm.
Effects of divalent cations on in vitro maturation of bovine oocytes
Authors: Leibfried Lorraine , First Neal L. 
Published: June 2005

AbstractLowering the external concentrations of both Mg+2 and Ca+2 caused failure of meiotic resumption invitroof bovine, oocyte‐cumulus complexes. Lowering of external Ca+2 levels singly had no effect on either meiotic resumption or completion of the first meiotic division. Lowering of external Mg+2 concentration on meiotic resumption invitro when Ca+2 was present, did interfere with the completion of the first meiotic division. The result was arrest of oocyte matuaration between germinal vesicle breakdown and formation of the first metaphase plate.
Salt and water balance in the oligohaline clam, Rangia cuneata III. Reduction of the free amino acid pool during low salinity adaptation
Authors: Henry Raymond P. , Mangum Charlotte P. 
Published: June 2005

AbstractDuring adaptation to low salinity (from 20 to 2 ppt), the estuarine clam Rangia cuneata reduces the size of a pool of free amino acids in adductor muscle fibers, presumably to control cell volume. The levels of both free amino acids and ammonia in the blood increase, but the rise in free amino acids is much greater. While free amino acid excretion is never very great, ammonia excretion rises shortly after valve opening and remains high throughout the period of adaptation Evaluation of the convection capability of the cardiovascular system suggests that the rate of free amino acid excretion cannot explain the loss of these substances as such from the tissues. Conversely, the levels of ammonia in blood cannot explain the rate of excretion. We suggest that most of the free amino acids are extruded from the cells and transported to a central site of deamination, from which ammonia is excreted. In situ deamination in the various tissues may occur after the initial stages of low salinity adjustment, but it never appears to explain the major fraction of ammonia excretion.
Changes in pituitary responsiveness to luteinizing hormone‐releasing hormone during an annual cycle in the domestic duck, Anas platyrhynchos L.
Authors: Balthazart J. , Willems J. , Hendrick J. C. 
Published: June 2005

AbstractOn four occasions during an annual cycle, 5–7 male domestic ducks were injected with two different doses (5 and 20 μg) of synthetic luteinizing hormone‐releasing hormone (LHRH) to study the possible changes in responsiveness of the pituitary. The luteinizing hormone (LH) and the follicle‐stimulating hormone (FSH) were measured in the plasma samples collected after these injections. The induced release of LH changes from one period of the year to another, being minimum in March at the height of the, reproductive season. The LHRH injection also induces the release of some FSH but only in limited amounts. The changes in pituitary responsiveness to LHRH are negatively correlated to changes in the circulating LH level (it is high when the plasma LH is low and vice versa). This suggests that the hypothalamic synthesis and release of LHRH must also change during the year.
Electrical activity in cardiac mutant axolotl hearts
Authors: Epstein Miles L. , Lemanski Larry F. 
Published: June 2005

AbstractElectrical recordings from the hearts of both cardiac lethal mutant and normal embryos showed the presence of action potentials conducted over the heart tube. Ionic coupling and gap junctions also were observed in both. These results suggest that the absence of heart function in mutant embryos does not result from a defect in electrical activity.
Effector mechanism in the response of Schistosoma mansoni miracidia to snail‐conditioned water
Authors: Roberts Thomas M. , Linck Richard W. , Chernin Eli 
Published: June 2005

AbstractSchistosoma mansoni miracidia respond to snail‐conditioned water (SCW) by sharply increasing their rate of turning when they encounter abrupt decreases in stimulant concentration (Roberts et al., '79). We examined the role of the cilia and the subepithelial muscles in the turning behavior of stimulated miracidia. Several lines of evidence indicated that miracidia do not turn by altering their ciliary beat. Ciliary beating on detergent‐treated miracidia was reactivated using solutions containing ATP and Mg2+. These organisms were unable to turn spontaneously, a characteristic of live miracidia. Several divalent cations which stimulate increased turning of intact miracidia failed to support ciliary reactivation of detergent‐treatedor, ganisms. Further, intact miracidia increased their rate of turning in gradients of Mg2+, but detergent‐treated organisms swimming in reactivation solution did not turn in Mg2+ gradients.High speed cinematography of intact miracidia swimming in gradients of SCW or Mg2+ illustrated that turning is invariably accompanied by flexion of the body. This bending occurred only at the transverse interciliary ridges between the first, and second, and second and third tiers of ciliated plates. Flexion was not observed at the interciliary ridge between the third and fourth tiers of plates, suggesting that miracidia turn by contracting specific portions of their subepithelial musculature.
Color and color adaptation of the European tree frog, Hyla arborea
Authors: Nielsen Hans Ingolf 
Published: June 2005

AbstractThe colors and color adaptation of the European tree frog, Hyla arborea, have been investigated by means of reflectance microspectrophotometry. The results are compared to those previously published on Hyla cinerea.The two species have a number of colors in common (yellow green, light green, green, dark green, black‐green, and olive green), while grey colors are assumed only by Hyla arborea and lemon yellow (olive yellow) only by Hyla cinerea. The physical qualities of these colors and the corresponding states of the chromatophores are presented and discussed.Hyla arborea apparently adapts better, and thus more predictably to its background than Hyla cinerea (as judged with the eyes of man). Both adapt to a certain degree to the lightness of the background, but the former also shows a certain adaptation to the purity, and it has a greater ability to change its hue, although a definite adaptation to background hue could not be determined.In Hyla arborea, the changes in the xanthophores seem to be paralleling those of the iridophores, but the changes in the melanophores appear to be independent. For this species, as well as for Hyla cinerea, more than one factor must therefore be regulating the adaptive color change. A number of possibilities are discussed.
Development of naked growing mouse oocytes in vitro
Authors: Bachvarova Rosemary , Baran Madelyn M. , Tejblum Ana 
Published: June 2005

AbstractHalf grown oocytes were released from follicles of 7‐day‐old mouse ovaries during overnight culture. Naked oocytes free of attached follicular cells were cultured in MEM plus 10% fetal calf serum over the developing monolayer of ovarian cells. Oocytes increased in diameter for a period of at least a week at 1.6 μ per day, or 70% of the in vivo growth rate. The ultrastructure of cytoplasmic organelles in cultured growing oocytes was normal. During the second week, about 35% underwent spontaneous fragmentation, and at least 10–20% resumed meiotic maturation. We conclude that a significant fraction of naked oocytes reached a functional state comparable to that of normal full grown oocytes at a rate approaching the in vivo rate.Free oocytes with attached cells grew to a larger average diameter than naked oocytes, and incorporated 3H‐leucine 75% more rapidly. Naked oocytes cultured in the absence of ovarian cells did not grow, and died when pyruvate was omitted from the medium. Naked oocytes did not grow when cultured over primary mousefibroblasts, L‐cells, CHO cells, or hepatoma cells. Naked oocytes separated from the monolayer of ovarian cells by a 0.7 mm layer of agar grew at 60% of the rate of control oocytes.
Cell to cell contacts mediating mating‐type dependent recognition(s) during the preconjugant cell interactions of Oxytricha bifaria (ciliata, hypotrichida)
Authors: Ricci Nicola , Cetera Rosanna , Banchetti Rosalba 
Published: June 2005

AbstractThe direct conjugant interactions leading to pair formation (“Visible Reaction”) of Oxytricha bifaria were studied by means of enzymes acting on the cell surface. They are able to interrupt at successive stages the cell interactions occurring during the Visible Reaction. The results show that: 1) mating type specific cell recognition occurs during the Visible Reaction; 2) this recognition is a prerequisite for pair formation; and 3) cell to cell contacts leading to membrane fusion play a critical role in such a recognition.The system of the preconjugant interactions in O. bifaria is composed of, at least, two successive and distinct stages, each playing separate roles in the general strategy of conjugation: A) a waiting period and B) a Visible Reaction. During the waiting period, complementary cells interact from a distance by means of mating type specific soluble factors (gamones) (Esposito et al., '76), and become “ready” to contact other similarly “ready” cells. By means of direct interactionsmediated by mating type specific cell‐to‐cell contacts during the Visible Reaction, a cell can recognize the contacted potential partner as belonging either to a complementary mating type (“go ahead”), or to its own mating type (“interrupt the conjugation program”). A general model of preconjugant interactions in ciliates is briefly discussed.
Lactate dehydrogenase isozymes in the genus Xenopus: Species‐specific patterns
Authors: Vonwyl E. , Fischberg M. 
Published: June 2005

AbstractThe LDH isozymes of 13 species and subspecies of the genus Xenopus have been analysed electrophoretically. In seven species and subspecies, five isozymes were found as in most vertebrates. The remaining species display more than five bands.The gene which codes for the A subunit shows little variability. With one exception (X.fraseri), all species with 36 chromosomes and X.tropicalis with 20 chromosomes possess the same A gene or at least a gene product with the same mobility. In contrast to this, the gene which codes for the B subunit differs in all but one case, thus producing species‐specific isozyme patterns.An allelic polymorphism at the LDH‐B locus in an X.laevis subspecies was found. In heterozygotes, the expected 15 isozymes can clearly be visualized. Since X.laevis can be considered as being tetraploid in respect to X.tropicalis, the occurrence of three genotypes in the offspring of a single pair mating gives evidence that one LDH‐B locus was rendered silent during evolution.
Anhydrobiosis in nematodes: Biosynthesis of trehalose
Authors: Loomis Stephen H. , Madin K. A. C. , Crowe John H. 
Published: June 2005

AbstractThe pathway for the synthesis of trehalose in Aphelenchus avenae was demonstrated. As in other systems, the enzymes involved in the synthesis of trehalose of A. avenae were found to be trehalose phosphate synthetase (TPS) and trehalosephosphate phosphatase (TPP). Some of the characteristics of trehalose phosphate synthetase were studied. It was found that the rate limiting step in the reaction is catalyzed by TPS. Partially purified TPS was specific for UDPG as the glucosyl donor, and showed a pH optimum of 8.0. The partially purified enzyme has a Km of 0.6 mM and a Vmax of 2.2 × 10−3 μmoles/mg protein min for glucose‐6‐phosphate, and a Km of 2.4 mM and Vmax of 2.5 × 10−3 μmoles/mg protein minfor UDPG.
Anhydrobiosis in nematodes: Control of the synthesis of trehalose during induction
Authors: Loomis Stephen H. , O'Dell Steven J. , Crowe John H. 
Published: June 2005

AbstractControl of the synthesis of trehalose during the induction of anhydrobiosis was examined. Kinetic parameters for TPS did not change during the induction, indicating that there was no de novo synthesis of an isozyme. TPS activity doubled in the presence of a mixture of Na+, K+, Mg++, and Ca++ at concentrations normally found in the worms during induction. The concentration of glucose‐6‐phosphate increased from about 2 mM in wet worms to about 12 mM at the end of induction, and the concentration of UDPG increased from about 1 mM in wet worms to about 9 mM at the end of induction. The concentration of UDPG was found to be rate limiting. Trehalase activity decreased by half during the induction period. The significance of these data as related to the control of the synthesis of trehalose was discussed.
Pattern regulation of mesoderm in transplanted and supernumerary limbs of the cockroach. I. The final morphology
Authors: Steinbach Paul A. , Josephson Robert K. 
Published: June 2005

AbstractMuscles, nerves, and tracheae were examined histologically in clusters of three limbs arising from single mesothoracic leg sockets in the cockroach, Periplaneta americana. The three‐limbed preparations were produced by amputating a normal legand replacing it with a contralateral leg from a donor animal, with the anterior‐posterior (A‐P) axis of the graft reversed relative to the A‐P axis of the host. After a few molts, two supernumerary limbs develop from the host/graft junction, one anterior and one posterior to the graft. Three to nine months after the operation, femurs from the supernumerary and graft limbs possess identifiable muscles which are, however, not as well developed as those of normal limbs. Supernumerary coxae rarely possessidentifiable musculature, but distal regions of the transplant coxae contain muscles of nearly normal morphology. Near the host/graft junction, the coxal muscles are disorganized, producing a proximal to distal gradient in muscle organization within thecoxa. The extensive disorganization near the host/graft junction is primarily a result of the reversed axis, since in grafts of ipsilateral limbs without axis reversal, there is considerably less muscle disorganization near the host/graft junction. Large, nerves and large tracheae were often located in supernumerary and graft femurs and in graft coxae in approximately the same positions as in normal limbs.
Properties of pyruvate kinase and flagellar ATPase in rabbit spermatozoa: Relation to metabolic strategy of the sperm cell
Authors: Storey Bayard T. , Kayne Fredrick J. 
Published: June 2005

AbstractRabbit sperm pyruvate kinase remains bound to the cell structure of hypotonically treated mature rabbit epididymal spermatozoa (HTRES). It displays kinetic behavior very similar to that of rabbit muscle pyruvate kinase with regard to KM values for substrates, activation by monovalent and divalent cations, inhibition by phenylalanine which is reversed by alanine, and lack of activation by fructose‐1,6‐biphosphate. The flagellar ATPase also remains bound to the cell structure of HTRES, whosemotility may be reactivated by a source of ATP. It requires Mg+2 for activity; the KM for both ATP and Mg+2 is 0.2 mM, implying that MgATP is the substrate. The ATPase activity is not inhibited by ouabain, oligomycin, or vanadate, which also do not affect reconstituted motility, and is not affected by cyclic AMP in the presence of an inhibitor of phosphodiesterase. The activities of pyruvate kinase and the flagellar ATPase in a given preparation of HTRES are comparable. Rabbit, spermatozoa have a metabolic strategy which is very similar to muscle cells. This suggests that the major use of the sperm cell's metabolic machinery is maintenance of energy for the contractile work of motility and that only minor amounts of metabolicenergy appear to be consumed in other reactions, including those involved in fertilization.
Hemoglobin polymorphism in adult cutthroat trout, Salmo clarkii
Authors: Braman J. C. , Stalnaker C. B. , Klar G. T. , Farley T. M. 
Published: June 2005

AbstractHemoglobin polymorphism was detected in a population of adult cutthroat trout by employing starch gel electrophoresis. Variation occurred only in the cathodally migrating hemoglobins. Six electrophoretic patterns were assumed to be present; however, the existence of a greater degree of complexity has not been ruled out. Eight of the 93 adult cutthroat trout sampled displayed a hemoglobin electrophoretic pattern identical to that obtained from adult rainbow trout.
Effects of cocaine on melanophore responses to catecholamines and KCl in the isolated caudal fin of the marine goby, Tridentiger trigonocephalus
Authors: Katayama Heizaburo 
Published: June 2005

AbstractEffects of cocaine on melanophore responses to catecholamines and KCl were investigated in the isolated caudal fin of fish to obtain evidence for the neuronal uptake of the catecholamines and the released adrenergic transmitter in the melanophore nerve. In the presence of 10−4M cocaine, pigment aggregation responses of normal melanophores to l‐noradrenaline (NA) and l‐adrenaline (A) were augmented, while aggregation responses to dopamine (D) and isoprenaline (Iso) were partly suppressed. Immediately after the cocaine (10−4M) treatment, the sensitivity of the normal melanophores to NA or A was greatly enhanced and aggregation responses to these catecholamines were greatly augmented. This is probably due to the blocking effect of cocaine on the neuronal uptake of the catecholamines. Such supersensitivity to the catecholamines of the normal melanophores was approximate to that of denervated melanophores. Probably, the supersensitivity of the denervated melanophores to NA and A mainly results from impairment of the neuronal uptake of the catecholamines. The sensitivity of melanophores to D or Iso was somewhat enhanced after denervation. After pretreatment with 10−4M cocaine, the pigment aggregating response to KCl was augmented. In the presence of 10−4M cocaine, pigment dispersion in the physiological solution was slowed down when the pigment had been made to aggregate by KCl or administered NA. It is highly probable that the exogenous NA, A, or the released adrenergic transmitter is taken up by the melanophore nerve endings. D and Iso are also probably taken up but only to a very limited extent.