Sara Serafina Sánchez

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The neural crest is induced at the border of the neural plate in a multistep process by signals emanated from the epidermis, neural plate and mesoderm. In this work we show for the first time the existence of a neural crest maintenance step which is dependent on signals released from the mesoderm. We identified Endothelin-1 (Edn1) and its receptor (Ednra)(More)
In this work we carried out an ultrastructural analysis of the cell interface between oocyte and follicle cells during the oogenesis of the amphibian Ceratophrys cranwelli, which revealed a complex cell-cell interaction. In the early previtellogenic follicles, the plasma membrane of the follicle cells lies in close contact with the plasma membrane of the(More)
The aim of the present study was to show the participation and physiological role of calmodulin (CaM) and cAMP during vitellogenin endocytic uptake in the amphibian Xenopus laevis. The results showed a differential distribution of CaM in the ovary follicles during oogenesis. The CaM intracellular localization was not affected by gap junction's(More)
The objective of this study was to elucidate the signalling pathways initiated by cAMP once inside the Xenopus laevis oocyte, where it triggers and maintains vitellogenin endocytic uptake. Our results showed the presence of Xepac transcripts at all stages of oogenesis and we demonstrated that a cAMP analogue that exclusively activates Xepac, 8-CPT, was able(More)
The biological activity of the extracellular material (ECM) located in the dorsal and ventral regions of Bufo arenarum is assayed. Ectoblast cells were isolated and cultured with ECM taken from the embryonal regions. The epiblastic cells treated with dorsal ECM, mainly located at the interphase between the invaginating blastoporal lip and the overlying(More)
The formation of vitelline envelope (VE) during the oogenesis of Bufo arenarum (Amphibia Anura) is described. At the stage of early vitellogenesis, the first structures appear: the number of oocyte microvilli increases, and many cross sections of them are observed between the follicle cells and the oocyte. A filamentous material is observed inside the(More)
Bone morphogenetic proteins (BMPs) are critical molecules during gut morphogenesis. However, little is known about their participation in the homeostasis of adult gut and their possible role in diseases. Gastrointestinal complications occur during diabetes with loss of enteric neurons. In this study, we investigated the possible involvement of BMPs(More)
Amphibians respond to microbial infection through cellular and humoral defense mechanisms such as antimicrobial protein secretion. Most humoral defense proteins are synthetized in the skin. In this study we isolated two beta-galactoside-binding lectins with molecular weights of 50 and 56 KDa from the skin of Bufo arenarum. These lectins have significant(More)
Glucose- 6phosphate dehydrogenase (G-6PDH) stimulation by estradiol- 17beta has been studied in oviduct and liver of Bufa arenarum. OviducalG-6PDH has been found to be stimulated by a single dose of estradiol- 17beta (100 mug/100 g body weight), the stimulation being dependent on season. Hepatic G-6PDH of females is susceptible to hormonal stimulation,(More)
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