bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for a stimulating effect of prolactin on teleostean hatching enzyme secretion
Authors: Schoots André F. M. , de Bont Rob G. , Van Eys Guillaume J. J. M. , Denucé J. Manuel 
Published: June 2005

AbstractHomogenates of whole medakas and of trout prolactin lobes contain a factor that stimulates hatching enzyme secretion from medaka hatching gland explants. The elution volume in gel filtration indicates that the stimulating factor is a protein with a molecular weight of 19,000–20,000. Both its localization in the prolactin lobe and its apparent molecular weight suggest that this factor is prolactin. This is confirmed by an electrophoretic analysis of the biomajor products of the prolactin lobe, which demonstrates that prolactin is the major product found in the molecular mass range from 15,000 to 30,000 daltons. Since it is known that the pituitary gland of teleostean embryos has functional prolactin cells and that prolactin is an activator of integumentary glandular cells, we conclude that prolactin might be the primary stimulus in the activation of hatching gland cells leading to hatching enzyme secretion.
Immunological factors in Peromyscus speciation
Authors: Dawson Wallace D. , Reuning Sara C. , Finlay Mary‐F. 
Published: June 2005

AbstractReciprocal interspecific F1 hybrids of deermice (Peromyscus maniculatus) and oldfield mice (P. polionotus) differ significantly and substantially in fetal and placental, as well as adult, size and weight. Hybrid fetal mortality is associated with large conceptus size. Skin grafts were exchanged between and within the two species to ascertain whether any relationship exists between mean graft retention time and body size of fetuses and adults. P. maniculatus skin grafted to P. polionotus rejected significantly earlier than the reciprocal xenograft. All interspecific graft combinations rejected significantly earlier than intraspecific grafts. Pre‐immunization of female P. maniculatus with con‐ and trans‐specific paternal spleen cell antigens reduced fetal, placental, neonatal, and ten‐day size compared with controls. Size, weight, fertility, and graft rejection data were compared with several theoretical models. The data were consistent with the hypothesis that immunological disparity between the species could produce marked size variations in reciprocal hybrids. Multiple minor histocompatibility factors can account for large placental size and fetal mortality in Peromyscus hybrids. Physiological reproductive isolation may result from immunological differences between closely allied species.
Central organization of crustacean abdominal posture motoneurons: Connectivity and command fiber inputs
Authors: Miall R. Christopher , Larimer James L. 
Published: June 2005

AbstractIntracellular recordings and Lucifer dye injections were used to locate five of the six tonic abdominal flexor motoneurons, as well as several of the extensor motoneurons in the fourth abdominal ganglion of the crayfish, Procambarus clarkii. Each motoneuron was identified by its morphology and root records, and each was characterized by its inputs from identified flexion and extension‐evoking interneurons (command fibers). Finally its connections to other motoneurons were examined by current injection experiments.As indicated by others, the somata of most of the tonic flexor motoneurons are electrically silent; recordings were, therefore, made from neuropilar branches, but at unknown locations.The majority of motoneurons were found to be polysynaptically connected to the command neurons, although several apparent monosynaptic excitatory and inhibitory connections were also seen. Coupling between motoneurons was confirmed, but the major functional input to the motoneurons was from premotor interneurons. Coupling between motoneurons and interneurons is also indicated by the data, and may be responsible for the inhibition of some motoneurons seen during depolarizing current injections into other motoneurons. Again, such coupling is shown to be a minor influence in the overall organization of the behavior.The data suggest that flexion and extension behavior is predominantly organized via interneurons including the command fibers rather than by connections among the motoneurons themselves.
Effects of 25‐hydroxyvitamin D3 and 1,25‐dihydroxyvitamin D3 on embryonic chick bone in organ culture
Authors: Rosen Vicki , Clark Nancy B. 
Published: June 2005

AbstractThe ability of embryonic chick bone to respond to 25 hydroxy‐vitamin D3 and 1,25 dihydroxyvitamin D3 was assessed in organ culture. These metabolites were added to prelabeled chick embryo long‐bone explants, and the amount of calcium‐45 released into the medium after 24 or 48 h of hormone exposure was measured. For each time period a significant release of calcium‐45 from hormone‐treated bones was observed. The response to 25 hydroxyvitamin D3 and 1,25 dihydroxyvitamin D3 was always greater at 48 h and a clear dose‐dependency was established at this time as well. 1,25 dihydroxy vitamin D3 was the more potent resorbing agent at all concentrations tested. The results from this study suggest that vitamin D metabolites may be involved in bone regulation in the chick embryo.
Abnormal embryonic development induced by antiserum: A rapid method to isolate the responsible galactoprotein antigens
Authors: Leung Christopher C. K. 
Published: June 2005

AbstractIt has been well established that heterologous antiserum against whole rat kidney homogenate when injected into pregnant rats during the organogenetic period may induce abnormal embryonic development. A one‐step rapid method has been developed to isolate the responsible rat renal antigens by lectin‐affinity chromatography using soy bean agglutinin (SBA) or ricinus com‐munis agglutinin (RCA120). The purified antigens appeared to be galactoproteins with terminal nonreducing D‐galactose and/or N‐acetyl‐D‐galactosamine. Rabbit antisera produced against the galactoproteins were potent teratogenic agents.
Hormonally‐stimulated chloride transport in the eastern lubber grasshopper, Romalea microptera
Authors: Spring Jeffrey H. 
Published: June 2005

AbstractShort‐circuited recta of the lubber grasshopper show an initial rapid decline in the short‐circuit current (Isc) over the first 60–90 min in vitro. This is followed by a pseudo steady state during which Isc declines slowly and steadily until a true steady state is reached after 4 h. Isc can be stimulated 4–6 fold by the addition of homogenates of corpora cardiaca (CC) or cAMP to the hemocoel‐side of the preparations. This increase in Isc is accompanied by an increase in transepithelial electropotential difference and a large drop in transepithelial resistance. Tracer studies reveal that the initial decline in Isc and its subsequent restoration to high levels is almost entirely due to changes in the active uptake of chloride from the lumen‐side (J→H). Recta maintained in vitro show a graded response to increasing doses of CC homogenates with the threshold occurring near 0.002 gland pair. In all respects these results are qualitatively and quantitatively comparable to those previously reported for the desert locust, Schistocerca gregaria. This represents the first unequivocal demonstration of hormonally‐stimulated chloride transport in an insect other than Schistocerca, and suggests that this may represent a widespread mechanism for ionic homeostasis in insects. These experiments further lay the groundwork for attempts to purify both the hormone and the chloride translocator.
Growth and development of flight muscle in the locust (Schistocerca nitens, Thünberg)
Authors: Mizisin Andrew P. , Ready Neal E. 
Published: June 2005

AbstractThe isometric contraction kinetics, ultrastructure, and growth of locust flight muscle that is derived from body wall muscle (metathoracic dorsal longitudinal muscle) and from limb muscle (second metathoracic tergocoxal muscle) were studied during the last three nymphal instars and in the adult 2 weeks past the terminal molt. Two distinct developmental patterns were found that correlated with use during nymphal life. The second tergocoxal muscle (TC2) is used from the time of hatching as a coxal remoter. As such, its contraction kinetics and ultrastructure are characteristic of fast, phasic muscle, which predisposes it to use in the adult as a wing levator. In contrast, the dorsal longitudinal muscle (DLM) is nonfunctional during nymphal life; contraction kinetics and ultrastructure characteristic of fast, phasic muscle develop gradually in late nymphal life until the adult kinetics are attained 2 weeks past the terminal molt. Although growth in both of these muscles occurs as the result of increases in fiber number and cross‐sectional area, there are differences in the manner in which this growth is achieved. In the TC2, there is a continuous increase in fiber number through the last three nymphal instars. In contrast, in the DLM, the increase in fiber number is nearly complete by two molts before adulthood.
Vitamin A enhances forelimb regeneration in juvenile leopard frogs Rana pipiens
Authors: Cecil Mark L. , Tassava Roy A. 
Published: June 2005

AbstractThe effect of retinoids on forelimb regeneration in the leopard frog, Rana pipiens, was examined by the topical application of a concentrated solution of vitamin A palmitate to the amputated left limb stumps of 30 froglets. This treatment resulted in the enhancement of regeneration; regenerative outgrowths of experimental frogs were more frequent, larger in size, and had improved morphology compared to their untreated control counterparts. We conclude that vitamin A palmitate, topically administered in concentrated dosages, exerts a positive effect on the regenerative capacity of Rana pipiens.
Mating types and mating inducing substances in Euplotes octocarinatus
Authors: Heckmann Klaus , Kuhlmann Hans‐Werner 
Published: June 2005

AbstractThe complex pattern of reactions between cells of ten different mating types of Euplotes octocarinatus, a fresh water ciliate closely related to E. patella, is reported. Mixture of cells of two different types leads in the majority of combinations to the formation of both heterotypic and homotypic pairs after a waiting period of about 3 hours. In a few combinations only homotypic pairs of one of the two mixed types are formed. Both homotypic and heterotypic pairs undergo meiosis and complete conjugation. Cross breeding experiments show that the ten mating types are determined by four codominant alleles (mt1, mt2, mt3, and mt4) that control the production of four matinginducing signal‐substances or gamones (G1, G2, G3, and G4). These substances are secreted into the medium and induce mature cells of certain other mating types to transform into cells that are able to unite and form conjugant pairs. We suggest that the transformation of the cells into cells ready for conjugation is triggered by the binding of gamone molecules to gamone‐specific receptors and that mature cells usually expose receptors for all gamones except the ones they produce themselves.
The distribution of polymerized actin in the rat egg and its sensitivity to cytochalasin B during fertilization
Authors: Battaglia David E. , Gaddum‐Rosse Penelope 
Published: June 2005

AbstractThe distribution of polymerized actin in rat eggs fertilized in vitro was determined using NBD‐phallacidin (NBD‐ph). Unfertilized and fertilized eggs exhibited a 3–5‐μm‐thick band of fluorescence that encompassed the entire cortical cytoplasm. There was no dramatic increase in the staining of the cortex in association with any component of the fertilizing sperm during its incorporation into the egg. Unfertilized eggs and fertilized eggs obtained at intervals after sperm‐egg fusion were treated with cytochalasin B (CB; 5 μg/ml) and subsequently stained with NBD‐ph. Unfertilized eggs treated with CB exhibited a continuous ring of cortical staining identical to that seen in untreated eggs. Eggs treated with CB 15 min after sperm‐egg fusion exhibited small gaps in the cortical staining pattern, whereas those exposed to CB 1 hr after fusion exhibited larger gaps and the staining pattern appeared punctate. This pattern could be seen throughout the remainder of the 7 hr period of sperm incorporation and for at least 13 hr thereafter. CB‐treated fertilized eggs that were washed to remove the drug again exhibited uninterrupted cortical staining on treatment with NBD‐ph. CB also induced the resorption of surface elevations that are normally seen on the eggs during sperm incorporation, but it did not affect the morphology of unfertilized eggs. The sensitivity to CB during fertilization coincides with the onset of a variety of egg shape changes that occur during the period of sperm incorporation (Battaglia and Gaddum‐Rosse, Gamete Res., 10:107–118, 1984a). It is probable that activation of rat eggs by the fertilizing sperm induces a change in the state of actin assembly, which might be responsible, in part, for the behavior of the egg surface during sperm incorporation and subsequent developmental events.
Photoperiodic regulation of gametogenesis and growth in the sea urchin Strongylocentrotus purpuratus
Authors: Pearse John S. , Pearse Vicki B. , Davis Karen K. 
Published: June 2005

AbstractOur experiments demonstrate that both gametogenesis and growth in the sea urchin Strongylocentrotus purpuratus are under photoperiodic control. Juvenile sea urchins (4–8 mm diameter) were collected in September 1979 and reared for 18 months under two photoperiodic regimes with changing daylengths as in the natural annual cycle. One regime followed inphase (ambient) photoperiods; the other was kept 6 months out of phase with ambient photoperiods. In March of both 1980 and 1981 most of the in‐phase animals (like field animals) contained numerous gametes while the out‐of‐phase animals contained very few gametes. DNA synthesis (estimated by autoradiography with tritiated thymidine) was high in the in‐phase males and low in the out‐of‐phase males. In September of 1980, the situation was reversed. In animals exposed to two successive “winter” photoperiod regimes, gamete production continued for 6 months; in those exposed to two successive “summers,” there was little gamete production. These experiments suggest that either long days inhibit gametogenesis or short days enhance it. The normal peak of body growth in the summer and fall was also shifted 6 months out of phase in animals kept on the out‐of‐phase photoperiod regime; this shift was reflected in size, in weight, and in the growth zones of the skeletal plates. Feeding rates did not differ between animals on the two photoperiod regimes, suggesting that photoperiod does not influence energy intake but rather determines whether energy is allocated to body and gonad growth or to gametogenesis and gamete maintenance.
Protein gradients in byssal threads of some marine bivalve molluscs
Authors: Mascolo J. M. , Waite J. H. 
Published: June 2005

AbstractMany marine bivalve molluscs produce byssal threads for attachment to solid substrata. Small (< 10 mm) consecutive sections of the byssal threads of Mytilus edulis, M. californianus, Geukensia demissa, Atrina vexillum, and A. rigida were analyzed by amino acid analysis to determine if chemical composition remains constant as a function of location in thread segments. Nonlinear longitudinal protein gradients, probably involving collagen and an elastic protein, were found in the Mytilus species. In these, collagen peaks in the distal third of the thread. In Geukensia and the Atrina species, although the two differed greatly in composition, there is a clear nonvariability in composition of the thread within each species as a function of location in the thread. The adhesive plaque at the tip of the thread of all species examined differs substantially in composition from the remainder of the thread. Protein gradients in the threads of some bivalves may reflect specific adaptations evolved to respond to exposed habitats in high‐energy environments.
Developmental analysis of lipids from wild‐type and adipose60 mutants of Drosophila melanogaster
Authors: Teague Barbara Dean , Clark Andrew G. , Doane Winifred W. 
Published: June 2005

AbstractA comparative developmental analysis was made of lipids from wild‐type and adipose60 (adp60) mutants of Drosophila melanogaster. The lipid content and fatty acid profiles of late third instar larvae, pupae, and mature adults were characterized in methanol:chloroform extracts utilizing thin layer and gas‐liquid chromatography. Total lipid content of mutant adults was approximately twice that of the wild‐type, but no genotypic differences in lipid content were seen in earlier developmental stages. No sexual dimorphism was observed in total lipid content, although fatty acid profiles revealed some sexual differences. Many stage‐specific differences in fatty acid profiles and lipid content were developmentally associated with each genotype. Mutants tended to retain the larval phenotype in lipid content and, to a lesser extent, in fatty acid profile. In comparison to wild‐type, mutants tended to have increased lipid saturation, especially in 16‐carbon fatty acids in mature adults and in 18:0 fatty acids in late larvae and pupae. No significant difference between the mutants and wild‐type appeared in the developmental profiles for 14:1 fatty acid isomers. Hence, adp60 does not alter the desaturation‐elongation pathway, a secondary pathway for fatty acid desaturation in Drosophila, which received support from this analysis.
Spawning cycles of the Gulf killifish, Fundulus grandis, in closed circulation systems
Authors: Hsiao Shyh‐Min , Meier Albert H. 
Published: June 2005

AbstractGulf killifish, Fundulus grandis, spawned daily in aquaria held on 12‐h daylengths and 23°C. However, the number of eggs spawned varied from one day to another. Statistical analyses of the data revealed the presence of 13‐day (semilunar) cycles of spawning in five of seven aquaria that persisted for as long as 4 months. In addition to semilunar cycles, short (about 3 days) cycles were also common. Because each aquarium usually held 21 females, the existence of both 3‐day and 13‐day cycles suggests that there was synchronization within each group. There was also synchronization of 13‐day cycles between aquarium groups with a common recirculating water supply. Although the 13‐day cycle may be essentially an endogenous free‐running semilunar rhythm, exogenous timing of this cycle is supported by the strong coherence between it and the concurrent high‐tide cycles on the Louisiana Gulf coast.
Effect of cutting the zona pellucida on the pronuclear transplantation in the mouse
Authors: Tsunoda Y. , Yasui T. , Nakamura K. , Uchida T. , Sugie T. 
Published: June 2005

AbstractA new and reliable pronuclear transplantation procedure for the mouse egg has been developed by McGrath and Solter ('83). To overcome the technical difficulties of such a procedure, especially in uniformly preparing enucleation pipettes and in reducing damages during micromanipulation, we have examined the effect of cutting the zona pellucida of the eggs. By making a slit in the zona of an egg, the time for pipetting and exchange of pronuclei between eggs was shortened because the sharp tip of the pipette was not necessary. Although the proportion of pregnant recipients and young obtained after transfer of pronuclear transplanted eggs cultured for 1 day or 3 days was quite low, it was significantly increased (70% for pregnancy rate and 32% for the young) following transfer of eggs cultured for 4 days. These values were comparable with those after transfer of unoperated eggs cultured to morulae and blastocysts.
Studies of three major proteases associated with guinea pig sperm acrosomes
Authors: Arboleda Carlos E. , Gerton George L. 
Published: June 2005

AbstractThe major proteases associated with guinea pig sperm were investigated by using immunological and electrophoretic techniques. Three major proteases were detected following sodium dodecyl sulfate‐polyacrylamide gel electrophoresis in gels containing 0.1% gelatin. These enzymes had molecular weights of 47,000, 34,000, and 32,000 relative to reduced protein standards and 58,500, 40,000, and 37,500 relative to unreduced standards. All three protease activities were present in acid extracts of sperm, detergent extracts of sperm, and the soluble acrosomal components of sperm released following induction of the acrosome reaction with the Ca2+‐ionophore A23187. As determined by indirect immunofluorescence, an antibody to purified boar acrosin specifically cross‐reacted with the acrosomes of guinea pig sperm. Decreased fluorescence was associated with sperm that had lost their acrosomes. Immunoblot analysis demonstrated that this antibody reacted with the 47,000 Mr protease but not the 32,000 and 34,000 Mr proteases. All three proteases were maximally active in the pH 7.0–8.5 region and were inhibited by classical inhibitors of acrosin activity. During a 3‐hour incubation period, MgCl2 (10 mM) inhibited the activities of the 32,000 and 34,000 Mr proteases while the 47,000 Mr protease was stimulated. Although these proteases shared properties that would classify them as trypsin‐like proteases, only the 47,000 Mr protease could be definitely classified as a member of the proacrosin‐acrosin family based upon cross‐reaction with an antibody to purified boar acrosin.
Mechanisms regulating the ovarian cycle in the frog Rana cyanophlyctis: Effect of unilateral ovariectomy, season, feeding, human chorionic gonadotrophin, and estradiol‐17β
Authors: Saidapur S. K. , Prasadmurthy Y. S. 
Published: June 2005

AbstractEffects of 30‐day unilateral ovariectomy (ULO) on compensatory ovarian hypertrophy (COH) was studied in adult frog Rana cyanophlyctis in relation to reproductive phase/season, feeding, and treatment with human chorionic gonadotrophin (HCG) or estradiol‐17β. Compensatory growth of the remaining ovary was assessed in terms of weight as well as changes in the dynamics of the pool sizes of different oocytes viz., first growth phase (FGP), medium‐sized second growth phase (MSGP), large‐sized second growth phase (LSGP), and atretic oocytes. The frogs were fed with live guppies 6 days a week. The effect of underfeeding on COH was studied in the frogs fed once a week. The ovaries removed at operation and those of the sham‐operated frogs were used for comparison (controls).COH occurred in both pre‐ and postbreeding phases (February and November, respectively). In both instances follicular atresia was greatly reduced. In February, COH was due to recruitment of both MSGP and LSGP oocytes. The number of these oocytes increased significantly over controls, and the ovarian weight nearly doubled. However, in November COH occurred because of an increase in FGP oocytes and therefore total oocytes, but there were no changes in the ovarian weights. Administration of 20 IU HCG (6 days a week) had no influence on the basic pattern of COH‐response exhibited by the remaining ovary in relation to reproductive phase/season, but it increased the recruitment of oocytes, i.e., FGP oocytes in November and SGP oocytes in February. Follicular atresia was drastically reduced with HCG. Underfeeding or treatment with estradiol‐17β abolished the COH in both February and November. In addition, follicular atresia increased markedly in the remaining ovary.The findings suggest that reproductive phase and season influence the COH‐response of the remaining ovary and ovarian sensitivity to gonadotrophins. Seasonal changes in the pool sizes of FGP and SGP oocytes in the frog appear to be governed by the interactions between the various factors such as gonadotrophins, ovarian sensitivity, and season. The rate of follicular atresia is primarily regulated by the changing levels of gonadtrophins. Adequate feeding is essential for proper ovarian function in the frog. The present study suggests that for determining COH, especially in seasonal breeders, it is necessary to consider the pool sizes of different‐stage oocytes since ovarian weight alone is not a reliable criterion.