Glycemia Regulation: From Feedback Loops to Organizational Closure.

Endocrinologists apply the idea of feedback loops to explain how hormones regulate certain bodily functions such as glucose metabolism. In particular, feedback loops focus on the maintenance of the plasma concentrations of glucose within a narrow range. Here, we put forward a different, organicist perspective on the endocrine regulation of glycaemia, by relying on the pivotal concept of closure of constraints. From this perspective, biological systems are understood as organized ones, which means that they are constituted of a set of mutually dependent functional structures acting as constraints, whose maintenance depends on their reciprocal interactions. Closure refers specifically to the mutual dependence among functional constraints in an organism. We show that, when compared to feedback loops, organizational closure can generate much richer descriptions of the processes and constraints at play in the metabolism and regulation of glycaemia, by making explicit the different hierarchical orders involved. We expect that the proposed theoretical framework will open the way to the construction of original mathematical models, which would provide a better understanding of endocrine regulation from an organicist perspective

Is systems biology a promising approach to resolve controversies in cancer research?

At the beginning of the 21st century cancer research has reached an impasse similar to that experienced in developmental biology in the first decades of the 20th century when conflicting results and interpretations co-existed for a long time until these differences were resolved and contradictions were eliminated. In cancer research, instead of this healthy "weeding-out" process, there have been attempts to reach a premature synthesis, while no hypothesis is being rejected. Systems Biology could help cancer research to overcome this stalemate by resolving contradictions and identifying spurious data. First, in silico experiments should allow cancer researchers to be bold and a priori reject sets of data and hypotheses in order to gain a deeper understanding of how each dataset and each hypothesis contributes to the overall picture. In turn, this process should generate novel hypotheses and rules, which could be explored using these in silico approaches. These activities are significantly less costly and much faster than "wet-experiments". Consequently, Systems Biology could be advantageously used both as a heuristic tool to guide "wet-experiments" and to refine hypotheses and test predictions

Centrolene savagei

Number of Pages: 11Geological SciencesIntegrative Biolog

Aprendizaje por proyectos: formación del profesorado de infantil

La formación del profesorado en la actualidad presenta nuevos retos en el campo de las lenguas. El uso de metodologías como el aprendizaje basado en proyectos (ABP) se encuentra cada vez más extendido en todas las etapas educativas. En el campo de la lengua extranjera en Infantil también se lleva a cabo esta metodología y es esencial que los profesores realicen durante su etapa formativa experiencias propias del ABP. Con un total de 170 alumnos se procedió a crear un proyecto en torno a la invención de un cuento infantil bilingüe basándonos en la premisa de que todo profesor tiene que adquirir ciertas competencias relacionadas con la autonomía en el aprendizaje, una adecuada dicción, control del lenguaje gestual, n, preparación de exposiciones, etc. tareas esenciales para la asignatura de lengua. El resultado fue la adquisición de competencias para realizar ABP a través de la realización propia de un proyecto basado en la creación de un cuento bilingüe para la etapa de infantil

Endocardial-mesenchymal transition underlies fusion of the conotruncal ridges during embryonic cardiac outflow tract septation

The embryonic cardiac outflow tract (conotruncus) is a single tubular chamber that connects the right ventricle with the aortic arch arteries. It contains two opposite, long and helical mesenchymal cushions covered by endocardial cells (conotruncal ridges). Conotruncal division (septation) gives rise to the adult right and left outflows together with the aortic and pulmonary valves. It takes place by fusion of the two opposite ridges and formation of the conotruncal septum. Although the participation of neural crest cells in septation is well established, the mechanism of fusion of the conotruncal ridges remains unknown. Defects in fusion have been shown to produce bicuspid aortic valve, the most prevalent human congenital cardiac malformation, in a hamster model. Three fusion mechanisms have been proposed to operate during embryonic development: epithelial adhesion, epithelial apoptosis and epithelial-mesenchymal transition (EMT). The first mechanism entails the expression of adhesion molecules and the maintenance of the identity of cells in contact, whereas in the other two, epithelial cells covering the fusing structures disappear by apoptosis or by transforming into mesenchymal cells. The objective of this study is to elucidate the mechanism involved in the fusion of the conotruncal ridges. Immunofluorecence techniques were used in ED 11-12 hamster embryos. The results indicate that the mechanism of EMT, but not epithelial adhesion or apoptosis, is involved in the process of fusion of the conotruncal ridges. The EMT mechanism associated with conotruncal septation seems to be uncoupled from the process of formation of the endocardial cushions, which takes place at early stages. With these results, we can raise the hypothesis that defects in the EMT process may lead to different morphological types of bicuspid aortic valve.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This study was supported by P10-CTS-6068 (Junta de Andalucía), CGL2014-52356-P and CGL2017-85090-P (Ministerio de Economía y Competitividad), contract UMAJI75 (Junta de Andalucía, European Social Fund), and Universidad de Málaga

The anatomical components of the cardiac outflow tract of the bichir, polypterus senegalus. Evolutionary significance

El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013.Anatomical Record, Volume 296, Special Feature — 1: P-077.In chondrichthyans and actinopterygians, the outflow tract of the heart, namely, the cardiac portion intercalated between the ventricle and the ventral aorta, consists of two anatomical components: conus arteriosus and bulbus arteriosus. In chondrichthyans and extant representatives of phylogenetically ancient actinopterygian groups, the conus and bulbus are well-developed in size, whereas in most teleosts, the bulbus is markedly larger than the conus. Current knowledge about the cardiac outflow tract of the polypteriformes is scarce and highly contradictory, a fact that contrasts with their crucial phylogenetic position at the source of the actinopterygian lineage. In fact, it remains uncertain whether they have a bulbus at the arterial pole of the heart. The present study aimed to elucidate the anatomical arrangement of the cardiac outflow tract of the bichir in an attempt to improve our understanding of the evolution of the vertebrate heart. We examined the hearts from 12 bichirs using histochemical and immunohistochemical techniques. Our findings showed that the outflow tract of the bichir consists of two components, namely, a long conus arteriosus, largely composed of myocardial tissue and furnished with a variable number of valves at its luminal side, and a very short, elastin rich bulbus arteriosus, devoid of myocardium. The bulbus has an arterial-like histological composition. However, it differs from the aorta because it has a thicker wall, shows a different arrangement of the histological elements, is covered by the epicardium and is crossed by coronary arteries. The present observations are consistent with the notion that the conus arteriosus and the bulbus arteriosus have coexisted from the beginning of the jawed vertebrate radiation. This is of particular interest, because there is evidence that the bulbus arteriosus, which is a second heart field derivative, is homologous with the intrapericardial portions of the aorta and pulmonary artery of birds and mammals.Proyecto CGL2010-16417/BOS; Fondos FEDER

Actividad glicosidásica de bacterias ácido lácticas (BAL) y bifidobacterias aisladas de leche materna

Trabajo presentado en la VI Jornadas Complutenses, V Congreso Nacional de Investigación para Alumnos de Pregrado en Ciencias de aa Salud y X Congreso de Ciencias Veterinarias y Biomédicas.Las bacterias ácido lácticas (BAL) y las bifidobacterias tienen una gran importancia por su carácter probiótico. El interés por estos microorganismos ha fomentado su aislamiento de diversas fuentes y el estudio de sus propiedades, siendo la actividad glicosídica una de las menos estudiadas.Peer Reviewe

On physicalism and downward causation in developmental and cancer biology

International audienceThe dominant position in Philosophy of Science contends that downward causation is an illusion. Instead, we argue that downward causation doesn't introduce vicious circles either in physics or in biology. We also question the metaphysical claim that "physical facts fix all the facts." Downward causation does not imply any contradiction if we reject the assumption of the completeness and the causal closure of the physical world that this assertion contains. We provide an argument for rejecting this assumption. Furthermore, this allows us to reconsider the concept of diachronic emergence