Scielo RSS <![CDATA[Biological Research]]> https://scielo.conicyt.cl/rss.php?pid=0716-976020000001&lang=en vol. 33 num. 1 lang. en <![CDATA[SciELO Logo]]> https://scielo.conicyt.cl/img/en/fbpelogp.gif https://scielo.conicyt.cl <![CDATA[Ciencia y Educación: Una tarea pendiente]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100001&lng=en&nrm=iso&tlng=en <![CDATA[Discurso Chile-CIENCIA 2000]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100002&lng=en&nrm=iso&tlng=en <![CDATA[Las empresas chilenas, la ciencia y la tecnología]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100003&lng=en&nrm=iso&tlng=en <![CDATA[EDUCACIÓN SUPERIOR: DESAFÍOS Y TAREAS]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100004&lng=en&nrm=iso&tlng=en <![CDATA[Rafael Vicuña es testigo experto en importante juicio internacional sobre patentes]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100005&lng=en&nrm=iso&tlng=en <![CDATA[Ca-activated K channels: the ins and outs of calmodulin]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100006&lng=en&nrm=iso&tlng=en <![CDATA[Hemoglobin affinity for oxygen in three subspecies of toads (<I>Bufo sp.</I>) living at different altitudes]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100007&lng=en&nrm=iso&tlng=en Blood oxygen affinity and red blood cell properties were measured in three subspecies of genus Bufo: Bufo spinulosus limensis, collected at sea level and at an average day temperature of 20ºC; Bufo spinulosus trifolium, from 3100 m, average day temperature of 15ºC; and Bufo spinulosus flavolineatus, from 4100 m, average day temperature of 10ºC. Electrophoresis of the hemoglobin showed the same component in each of the three subspecies. At 20ºC the blood oxygen affinities (P50) showed small differences between Bufo spinulosus limensis and Bufo spinulosus trifolium, whereas the value for Bufo spinulosus flavolineatus was markedly lower. At 10ºC, the ambient temperature of Bufo spinulosus flavolineatus, the P50 was extremely low compared with the other two subspecies at their corresponding ambient temperatures <![CDATA[Characterization and mapping of an informational suppressor in <I>Aspergillus nidulans</I>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100008&lng=en&nrm=iso&tlng=en The present work was undertaken to characterize a suppressor gene present in a mutant strain of A. nidulans obtained with NTG (N-Methyl-N'-Nitro-N-Nitrosoguanidine). Analyses of this mutant have shown that this suppressor, designated suO1, induces phenotypic co-reversion of several auxotrophic mutations and makes the strain sensitive to aminoglycoside antibiotics and lower temperatures. suO1 has shown to be on linkage group VIII. The vegetative growth of the mutant strain is very unstable because the suppressor gene induces the production of prototrophic mitotic sectors. The strains bearing the suO1 gene produce cleistothecia containing a reduced number of viable ascospores during the sexual cycle. The segregation of the genetic markers has also been observed in the mutant strain self crossed. From the above results it may be concluded that suO1 is an informational suppressor <![CDATA[Zinc fingers: DNA binding and protein-protein interactions]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100009&lng=en&nrm=iso&tlng=en The zinc finger domain is a very ubiquitous structural element whose hallmark is the coordination of a zinc atom by several amino acid residues (cysteines and histidines, and occasionally aspartate and glutamate). These structural elements are associated with protein-nucleic acid recognition as well as protein-protein interactions. The purpose of this review is to examine recent data on the DNA and protein binding properties of a few zinc fingers whose three dimensional structure is known <![CDATA[Ontogenetic changes in the fractal geometry of the bronchial tree in <I>Rattus norvegicus</I>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100010&lng=en&nrm=iso&tlng=en Respiration and metabolism change dramatically over the course of the development of vertebrates. In mammals these changes may be ascribed to organogenesis and differentiation of structures involved in gas exchange and transport and the increase in size. Since young as well as mature individuals must be well-designed if the species is to survive, the physiological changes during the development should be matched with geometrical or structural adjustments of the respiratory system. The aim of this study was to evaluate changes in the fractal geometry of the bronchial tree during the postnatal development of the rat. The average fractal dimension of the bronchial tree of the rats was 1.587, but that of juveniles was larger than that of the adults. We found a significant negative correlation between age and fractal dimension. This correlation could be considered be misleading because of the difficulty of separating age/body size effects. Nevertheless, because fractal dimensions of the bronchial tree of rabbits and humans are known to be similar, 1.58 and 1.57 respectively, the body size effect may be nil. To our knowledge, this is the first report of ontogenetic changes in the fractal dimension of the bronchial tree in mammals <![CDATA[IX REUNION ANUAL SOCIEDAD DE ECOLOGIA DE CHILE]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100011&lng=en&nrm=iso&tlng=en Respiration and metabolism change dramatically over the course of the development of vertebrates. In mammals these changes may be ascribed to organogenesis and differentiation of structures involved in gas exchange and transport and the increase in size. Since young as well as mature individuals must be well-designed if the species is to survive, the physiological changes during the development should be matched with geometrical or structural adjustments of the respiratory system. The aim of this study was to evaluate changes in the fractal geometry of the bronchial tree during the postnatal development of the rat. The average fractal dimension of the bronchial tree of the rats was 1.587, but that of juveniles was larger than that of the adults. We found a significant negative correlation between age and fractal dimension. This correlation could be considered be misleading because of the difficulty of separating age/body size effects. Nevertheless, because fractal dimensions of the bronchial tree of rabbits and humans are known to be similar, 1.58 and 1.57 respectively, the body size effect may be nil. To our knowledge, this is the first report of ontogenetic changes in the fractal dimension of the bronchial tree in mammals