1,720,975 research outputs found
Molecular structure of rDNA intergenic spacer (IGS) in Triturus: implication for the hypervariability of rDNA loci
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RNA binding properties and evolutionary conservation of the Xenopus multifinger protein Xfin
No full textGenetic control of development in Xenopus laevis
No full textIn this paper we address the question of how genes can control development by using Xenopus as a model system, since it combines the classical advantages of amphibian embryology with advanced molecular techniques. Several developmental regulator genes have been shown to encode for transcription factors which trigger the activation of downstream genes, thus resulting in a cascade of regulatory events. In the first two examples, we deal with regulatory events that underlie early body patterning in vertebrates, and with the role of homeobox transcription factors in deciphering positional information along the body axis. In the third example, we address the question of the role of post-transcriptional regulation in development by studying the possible regulatory role of a cytoplasmic zinc finger protein, presumably acting through RNA-protein interactions. The general idea is that understanding how genes can control development will hopefully lead to understanding the construction of a shape, and eventually of an organis
5-HT2B mediated signaling partecipates in retinal and craniofacial morphogenesis during Xenopus laevis developmen
No full textSerotonin 2B receptor signaling is required for craniofacial morphogenesis and jaw joint formation in Xenopus
No full textSerotonin (5-HT) is a neuromodulator that plays many different roles in adult and embryonic life. Among the 5-HT receptors, 5-
HT2B is one of the key mediators of 5-HT functions during development. We used Xenopus laevis as a model system to further
investigate the role of 5-HT2B in embryogenesis, focusing on craniofacial development. By means of gene gain- and loss-offunction
approaches and tissue transplantation assays, we demonstrated that 5-HT2B modulates, in a cell-autonomous manner,
postmigratory skeletogenic cranial neural crest cell (NCC) behavior without altering early steps of cranial NCC development and
migration. 5-HT2B overexpression induced the formation of an ectopic visceral skeletal element and altered the dorsoventral
patterning of the branchial arches. Loss-of-function experiments revealed that 5-HT2B signaling is necessary for jaw joint
formation and for shaping the mandibular arch skeletal elements. In particular, 5-HT2B signaling is required to define and sustain
the Xbap expression necessary for jaw joint formation. To shed light on the molecular identity of the transduction pathway
acting downstream of 5-HT2B, we analyzed the function of phospholipase C beta 3 (PLC) in Xenopus development and showed
that PLC is the effector of 5-HT2B during craniofacial development. Our results unveiled an unsuspected role of 5-HT2B in
craniofacial development and contribute to our understanding of the interactive network of patterning signals that is involved in
the development and evolution of the vertebrate mandibular arch
Chromosome location of the ribosomal RNA genes in Triturus vulgaris meridionalis (Amphibia, Urodela).IV. Comparison between in situ hybridization with H3 18S+28S rRNA and AS-SAT staining
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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