625 resultados para TUNGARA FROG
Resumo:
PAWP, a candidate sperm-borne oocyte activating factor, induces oocyte activation and acts upstream of the calcium signalling pathway, however, PAWP’s downstream signalling pathway in oocyte cytoplasm remains to be uncovered. Data from our lab suggested that the interacting partner of PAWP, at least in the frog (Xenopus laevis) model may be YAP, a highly expressed protein in amphibian and mammalian oocytes. Therefore, the objectives of this study were to confirm that PAWP’s predominant binding partner in Xenopus laevis oocyte is YAP; to determine if mammalian oocyte activation is also dependent on PAWP-YAP interaction; and to verify that the PAWP-YAP interaction during oocyte activation is dependent on the WWI domain module. By immunohistochemistry, YAP was localized predominantly in the cytosol of metaphase II-arrested Xenopus laevis oocytes, where presumably the PAWP-YAP interaction occurs. Utilizing Far Western blotting, YAP was identified as the predominant binding partner of PAWP, in metaphase II-arrested frog (Xenopus laevis), swine (Sus scrofa) and mouse (mus musculus) oocytes. The specificity of this interaction was then tested on Far Western blotting of mouse ovarian and oocyte cytosolic extracts, by competition with both wild-type and point-mutated recombinant WWI domains derived from YAP. The removal of GST from the wild-type WWI-GST fusion protein was a requirement for effective blockage of WWI module interaction between PAWP and YAP. As expected, the mutated WWI domain was ineffective in inhibiting the PAWP-YAP interaction. To conclude, this study identified YAP as the predominant binding partner of PAWP in both amphibian and mammalian oocytes, and showed this interaction is dependent on the WWI modular interaction. The results allow us to test the functional relevance of this WWI modular interaction during oocyte activation in vivo, in the future.
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In defense of Harriet Shelley.--Fenimore Cooper's literary offenses.--Traveling with a reformer.--Private history of the "Jumping frog" story.--Mental telegraphy.--Mental telegraphy again.--What Paul Bourget thinks of us.--A little note to M. Paul Bourget.--The invalid's story.--Stirring times in Austria.--The German Chicago.--Concerning the Jews.--About all kinds of ships.--From the "London times" of 1904.--A majestic literary fossil.--At the appetite cure.--Saint Joan of Arc.--In memoriam.--A biographical sketch.
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Wood engravings: frontispiece, ills., title vignette.
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How to tell to a story -- In defence of Harriet Shelley --Fenimore Cooper's literary offences -- Travelling with a reformer -- Private history of the "jumping frog" story -- Mental telegraphy again -- What Paul Bourget thinks of us -- A little note to M. Paul Bourget.
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Primera serie. Ligeia. -- Eleonora. -- Berenice. -- Morella. -- La caiguda de la casa Usher. -- El retrat oval. -- William Wilson. -- La mascara de la mort roja. -- El rei pesta. -- El pou 1 el Pèndol. -- Segona serie. El gat negre. -- El cor delator. -- El barril d'amontillado. -- Hop. -- Frog. -- Metzengerstein en el cas de M. Valdemar. -- L'illa de la fada. -- El poder de les paraules. -- Conversa d'Eiros i Charmion. -- Col·Lo-qui de monos i una. -- Uns quants mots amb una monia.
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How to tell a story.--In defence of Harriet Shelley.--Fenimore Cooper's literary offences.--Travelling with a reformer.--Private history of the "jumping frog" story.--Mental telegraphy again.--What Paul Bourget thinks of us.--A little note to M. Paul Bourget.
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Selections from the author's "Bajarz polski" published at Wilna in 1862.
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How to tell a story.--In defence of Harriet Shelley.--Fenimore Cooper's literary offences.--Travelling with a reformer.--Private history of the "Jumping frog" story.-- Mental telegraphy again.--What Paul Bourget thinks of us.--A little note to M. Paul Bourget.--The invalid's story.--The captain's story.--Stirring times in Austria.--Concerning the Jews.--From the London times of 1904.--At the appetite cure.--In memorium.-- Mark Twain: a biographical sketch.
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The student is determining the effect of after-load on the work done on a frog's muscle (source: Not Just Any Medical School by Horace W. Davenport)
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Thesis (Ph.D.)--University of Washington, 2016-06
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beta2-Laminin is important for the formation of neuromuscular junctions in vertebrates. Previously, we have inactivated the gene that encodes for beta2-laminin in mice and observed predominantly prejunctional structural defects. In this study, we have used both intra- and extracellular recording methods to investigate evoked neurotransmission in beta2-laminin-deficient mice, from postnatal day 8 (P8) through to day 18(P18). Our results confirmed that there was a decrease in the frequency of spontaneous release, but no change in the postjunctional response to such release. Analysis of evoked neurotransmission showed an increase in the frequency of stimuli that failed to elicit an evoked postjunctional response in the mutants compared to litter mate controls, resulting in a 50% reduction in mean quantal content at mutant terminals. Compared to littermate controls, beta2-laminin-deficient terminals showed greater synaptic depression when subjected to high frequency stimulation. Furthermore, the paired pulse ratio of the first two stimuli was significantly lower in beta2-laminin mutant terminals. Statistical analysis of the binomial parameters of release showed that the decrease in quantal content was due to a decrease in the number of release sites without any significant change in the average probability of release. This suggestion was supported by the observation of fewer synaptic vesicle protein 2 (SV2)-positive varicosities in beta2-laminin-deficient terminals and by ultrastructural observations showing smaller terminal profiles and increased Schwann cell invasion in beta2-laminin mutants; the differences between beta2-laminin mutants and wild-type mice were the same at both P8 and P18. From these results we conclude that beta2-laminin plays a role in the early structural development of the neuromuscular junction. We also suggest that transmitter release activity may act as a deterrent to Schwarm cell invasion in the absence of beta2-laminin.
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Amphisbaenians are legless reptiles that differ significantly from other vertebrate lineages. Most species dig underground galleries of similar diameter to that of the animal. We studied the muscle physiology and morphological attributes of digging effort in the Brazilian amphisbaenid Leposternon microcephalum (Squamata; Amphisbaenia), which burrows by compressing soil against the upper wall of the tunnel by means of upward strokes of the head. The individuals tested (
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Stabilizing selection is a fundamental concept in evolutionary biology. In the presence of a single intermediate optimum phenotype (fitness peak) on the fitness surface, stabilizing selection should cause the population to evolve toward such a peak. This prediction has seldom been tested, particularly for suites of correlated traits. The lack of tests for an evolutionary match between population means and adaptive peaks may be due, at least in part, to problems associated with empirically detecting multivariate stabilizing selection and with testing whether population means are at the peak of multivariate fitness surfaces. Here we show how canonical analysis of the fitness surface, combined with the estimation of confidence regions for stationary points on quadratic response surfaces, may be used to define multivariate stabilizing selection on a suite of traits and to establish whether natural populations reside on the multivariate peak. We manufactured artificial advertisement calls of the male cricket Teleogryllus commodus and played them back to females in laboratory phonotaxis trials to estimate the linear and nonlinear sexual selection that female phonotactic choice imposes on male call structure. Significant nonlinear selection on the major axes of the fitness surface was convex in nature and displayed an intermediate optimum, indicating multivariate stabilizing selection. The mean phenotypes of four independent samples of males, from the same population as the females used in phonotaxis trials, were within the 95% confidence region for the fitness peak. These experiments indicate that stabilizing sexual selection may play an important role in the evolution of male call properties in natural populations of T. commodus.