Resolución de problemas científicos escolares y promoción de competencias de pensamiento científico. ¿Qué piensan los docentes de química en ejercicio?

In the article the results of an investigation conducted within the framework of the project FONDECYT 1070795 are exposed. The aims of the research were to identify and characterize the representations and knowledge that teachers in service have, from an average level of education, with respect to the competences of scientific thought and problem solution, and the way in which both should be approached. With the use of an intentional sample of 133, teachers selected from a total of 117 who were incorporated to other phases of the research trough the administration of a questionnaire especially designed, was show the predominance of a very fragmented image, sometimes contradictory, about the solution of problems and about relation between competences of scientific thought; this representation incorporates aspects of great value for the formation of the competent students, and at the same time it includes other aspects that in no way favor this formation, according to the present assessments. It is remarkable that both competences for scientific thought and solution of problems are not constituted as a totality and coherent system in the thinking of the teachers who participated in the research. It should be pointed out that we found data that show an oscillating valuation of the subjective character of the problematic situations and the problem itself; these data show, as well, that teachers give a very important role to language. It is stated that teachers give an oscillating value to the fact that students must deal with theories. It should be noted too that their approaches to the algorithmic processes are very vague, and sometimes contradictory.En el artículo se exponen los resultados de una investigación realizada en el marco del proyecto FONDECYT 1070795, cuyo objetivo consistió en identificar y caracterizar las nociones que tienen los profesores de nivel medio respecto a las competencias de pensamiento científico y solución de problemas, y la manera en que ambos deben trabajarse en la enseñanza de la química. Con el empleo de una muestra intencional de 33 profesores, seleccionados de un total de 117 que se incorporaron a otras fases de la investigación y mediante la administración de un cuestionario especialmente diseñado, se logró poner de manifiesto que en ellos predomina una imagen fragmentada y a veces contradictoria de la solución de problemas y de las competencias de pensamiento científico; dicha representación incorpora aspectos de inestimable valor para la formación del estudiante competente, a la vez que incluye otros que en manera alguna favorecen dicha formación en correspondencia con las exigencias actuales. Es notable que competencias de pensamiento científico y solución de problemas no se constituyan como sistema totalmente coherente en la conceptualización de los profesores investigados. Como dato relevante, se constató la oscilante valoración del carácter subjetivo de las situaciones problémicas y los problemas; junto al papel importante que, en opinión de gran parte de los profesores, desempeña el lenguaje, se le otorga un valor oscilante al trabajo con la teoría por parte de los estudiantes; igualmente resulta difusa, y a veces contradictoria, su aproximación a los procesos de algoritmización

Fungal enzyme sets for plant polysaccharide degradation

Enzymatic degradation of plant polysaccharides has many industrial applications, such as within the paper, food, and feed industry and for sustainable production of fuels and chemicals. Cellulose, hemicelluloses, and pectins are the main components of plant cell wall polysaccharides. These polysaccharides are often tightly packed, contain many different sugar residues, and are branched with a diversity of structures. To enable efficient degradation of these polysaccharides, fungi produce an extensive set of carbohydrate-active enzymes. The variety of the enzyme set differs between fungi and often corresponds to the requirements of its habitat. Carbohydrate-active enzymes can be organized in different families based on the amino acid sequence of the structurally related catalytic modules. Fungal enzymes involved in plant polysaccharide degradation are assigned to at least 35 glycoside hydrolase families, three carbohydrate esterase families and six polysaccharide lyase families. This mini-review will discuss the enzymes needed for complete degradation of plant polysaccharides and will give an overview of the latest developments concerning fungal carbohydrate-active enzymes and their corresponding families

1B118 Dificultades de la enseñanza de la biología según el análisis crítico del profesor

La práctica pedagógica implica intencionar una serie de acciones enseñanza en pos de los aprendizajes de los estudiantes, sin embargo, éstas por su naturaleza contextual y forma particular de implementarlas puede favorecer o limitar el aprendizaje. La comunicación atiende al valor de la reflexión docente sobre la práctica como una opción para reconocer las dificultades de enseñanza. En este estudio de caso participó un profesor de biología quien realiza una observación participante y entrevistas focalizadas sobre las dificultades percibidas en su enseñanza. Del autoanálisis de su clase emergieron preocupaciones respecto a la enseñanza, consecuencias e implicancias para el aprendizaje en relación con el uso de recursos, preguntas y explicación. Se discuten los alcances de la reflexión sobre la acción pedagógica con énfasis en el desarrollo profesional docente

Estudio comparativo de protección producida por algunas vacunas al administrarlas individual y simultáneamente

In order to know the protective response after the individual and simultaneous application of vaccines, six groups of guinea pigs were vaccinated against anthrax, enterotoxemia caused by Clostridium perfringens, infectious bovine rhinotracheitis and rabies. The evaluation was performed 30 days after vaccination by using challenge test with the guinea pigs vaccinated against anthrax and rabies, and neutralization test in the animals vaccinated against enterotoxemia, infectious bovine rhinotracheitis and also rabies.It was not found significative differences in the protective response confered by the use of these vaccines applied in the individual or simultaneous form in a guinea pig model. It is discussed the obtained results.Con el fin de conocer si existen diferencias en las respuestas protectoras consecutivas a la administración de vacunas aplicadas individual y simultáneamente a otras, se sometió a seis grupos de cobayos a vacunaciones contra carbunclo bacteridiano, enterotoxemia por Clostridium perfringens, rinotraqueítis infecciosa bovina y rabia, las que se aplicaron bajo los dos esquemas citados. La evaluación de las respuestas protectoras se realizó 30 días después de la vacunación y se basó en pruebas de desafío para los cobayos vacunados contra carbunclo bacteridiano, pruebas de neutralización del efecto tóxico-hemolítico para los vacunados contra enterotoxemia, prueba de seroneutralización para los cobayos vacunados contra rinotraqueítis y pruebas de seroneutralización y desafío para los cobayos vacunados contra rabia. Los resultados obtenidos indican que no existen diferencias significativas en la capacidad protectora otorgada por las vacunas usadas, cuando éstas se aplican en forma individual o simultáneamente

Estudio comparativo de protección producida por algunas vacunas al administrarlas individual y simultáneamente

In order to know the protective response after the individual and simultaneous application of vaccines, six groups of guinea pigs were vaccinated against anthrax, enterotoxemia caused by Clostridium perfringens, infectious bovine rhinotracheitis and rabies. The evaluation was performed 30 days after vaccination by using challenge test with the guinea pigs vaccinated against anthrax and rabies, and neutralization test in the animals vaccinated against enterotoxemia, infectious bovine rhinotracheitis and also rabies.It was not found significative differences in the protective response confered by the use of these vaccines applied in the individual or simultaneous form in a guinea pig model. It is discussed the obtained results.Con el fin de conocer si existen diferencias en las respuestas protectoras consecutivas a la administración de vacunas aplicadas individual y simultáneamente a otras, se sometió a seis grupos de cobayos a vacunaciones contra carbunclo bacteridiano, enterotoxemia por Clostridium perfringens, rinotraqueítis infecciosa bovina y rabia, las que se aplicaron bajo los dos esquemas citados. La evaluación de las respuestas protectoras se realizó 30 días después de la vacunación y se basó en pruebas de desafío para los cobayos vacunados contra carbunclo bacteridiano, pruebas de neutralización del efecto tóxico-hemolítico para los vacunados contra enterotoxemia, prueba de seroneutralización para los cobayos vacunados contra rinotraqueítis y pruebas de seroneutralización y desafío para los cobayos vacunados contra rabia. Los resultados obtenidos indican que no existen diferencias significativas en la capacidad protectora otorgada por las vacunas usadas, cuando éstas se aplican en forma individual o simultáneamente

The role of alginate lyases in the enzymatic saccharification of brown macroalgae, Macrocystis pyrifera and Saccharina latissima

In this work, we have compared the carbohydrate content and the enzymatic saccharification of the brown algae Macrocystis pyrifera from Chile and Saccharina latissima from Norway. M. pyrifera contained 40% mannitol, 31% uronic acids and 15% glucose, while S. latissima contained 37% glucose, 30% uronic acids and 25% mannitol. Thus, the ratio between mannitol and glucose was much higher for M. pyrifera. Acid pre-treated and untreated algae were enzymatically saccharified in two steps; first at pH 7.5, 25 degrees C for 12 h with a blend of recombinant alginate and oligoalginate lyases, then the pH was changed to 5.2, a commercial cellulase cocktail was added and saccharification continued at 50 degrees C for 4 h. These experiments showed that the use of recombinant alginate lyases and oligoalginate lyases in combination with cellulases increased the release of glucose from untreated seaweed. However, for saccharification of pretreated algae, only cellulases were needed to achieve high glucose yields. Finally, it was shown that brown algae hydrolysates could be used as a growth medium to produce microbial ingredients, such as Candida utilis yeast.CONICYT REDES150014 Algal Biorefinery Network: Foods of Norway-ICDB of Chile Centre for Biotechnology and Bioengineering (CeBiB) FB-0001 Foods of Norway Centre for Research-based Innovation (Research Council of Norway) 237841/030 Research Council of Norway 23900

Pectin: An overview of sources, extraction and applications in food products, biomedical, pharmaceutical and environmental issues

Pectin is a complex versatile heteropolysaccharide of great importance to food, pharmaceutical and cosmetic industries. It is widely used in the food industry due to its thickening, gelling and emulsification properties and in biomedical and biomaterial applications on account of its potential anti-inflammatory and immunomodulatory effects as well as its biodegradability and biocompatibility properties. Pectin is also a soluble dietary fiber with several beneficial gastrointestinal and physiological effects. The multifunctionality of pectin is related to the nature of its molecule that has diverse chemical structures, physicochemical properties and potential functionalities depending on the sources where it is extracted and on the extraction methods. Therefore, this review focuses on the importance of pectin for today's food, pharmaceutical and cosmetic industries, compiling information on its composition and properties as determined by its origins, especially from waste biomass of the fruits and vegetables processing industry, on commercial applications and research needs. The suitability of the different extraction methods was also discussed, considering cost, energy consumption and productivity. Furthermore, the biodegradation of pectin as a complex process performed by a set of enzymes was also reviewed along with application purposes. Finally, future perspectives reveal pectin to be an astounding functional food ingredient requiring continuous research work

Intestinal Transcriptome Analysis Reveals Enrichment of Genes Associated with Immune and Lipid Mechanisms, Favoring Soybean Meal Tolerance in High-Growth Zebrafish (Danio Rerio)

The molecular mechanisms underlying fish tolerance to soybean meal (SBM) remain unclear. Identifying these mechanisms would be beneficial, as this trait favors growth. Two fish replicates from 19 experimental families were fed fishmeal-(100FM) or SBM-based diets supplemented with saponin (50SBM + 2SPN) from juvenile to adult stages. Individuals were selected from families with a genotype-by-environment interaction higher (HG-50SBM + 2SPN, 170 +/- 18 mg) or lower (LG-50SBM + 2SPN, 76 +/- 10 mg) weight gain on 50SBM + 2SPN for intestinal transcriptomic analysis. A histological evaluation confirmed middle intestinal inflammation in the LG- vs. HG-50SBM + 2SPN group. Enrichment analysis of 665 differentially expressed genes (DEGs) identified pathways associated with immunity and lipid metabolism. Genes linked to intestinal immunity were downregulated in HG fish (mpx, cxcr3.2, cftr, irg1l, itln2, sgk1, nup61l, il22), likely dampening inflammatory responses. Conversely, genes involved in retinol signaling were upregulated (rbp4, stra6, nr2f5), potentially favoring growth by suppressing insulin responses. Genes associated with lipid metabolism were upregulated, including key components of the SREBP (mbtps1, elov5l, elov6l) and cholesterol catabolism (cyp46a1), as well as the downregulation of cyp7a1. These results strongly suggest that transcriptomic changes in lipid metabolism mediate SBM tolerance. Genotypic variations in DEGs may become biomarkers for improving early selection of fish tolerant to SMB or others plant-based diets