Proyectos

The recently awarded Fondecyt Iniciación no. 11241126 (PI Jorge Romero) aims to determine the distribution and geometry of slope instability and its controlling factors (i.e., textural and compositional characteristics of rocks, their mass structure and discontinuities, and their mechanical rock properties) at the San José and Nevados de Chillán Volcanic Complexes. Specific objectives involve encompassing the production of thematic maps to represent the factors contributing to instability (e.g., magmatic intrusions, hydrothermal alteration areas, observed landslides, etc.) and defining and characterizing lithotechnical units based on field observations. In addition, it should determine the mechanical rock properties of natural samples based on laboratory tests that represent different scenarios. Lastly, these results should be incorporated into numerical models to represent unstable areas, failure planes, and conditions for failure.

Tenacibaculosis is an emerging pathogen recently classified as high-risk disease. Since 2020 it is the second pathogen after Piscirickettsia salmonis producing higher mortalities in Atlantic salmon. Diverses species of Tenacibaculosis has been described in Chile, but Tenacibaculum dicentrarchi present the higher prevalence in culture centers. Before 2018, underreporting of Tenacibaculosis was possible due to the external signology is similar with Piscirickettsiosis. P. salmonis is the main pathogen in Chilean salmon farming, causing the principals mortalities because of diseases. In recent years, concerns related to Tenacibaculosis and Piscirickettsiosis coinfection have increased due to detrimental effects on the health status of fish in comparison to the single infection. Our proposal aim to characterize the immune response elicit by T. dicentrarchi in Atlantic salmon and describe how it is related to a coinfection by P. salmonis. First, we propose the description of the single infection of T. dicentrarchi due to the lack of information about the immune response it induces in Atlantic salmon. Then, we propose the characterization of the coinfection between T. dicentrarchi and P. salmonis and the possible weaker of the health status of the fish due to T. dicentrarchi may favors the development of the secondary infection. Therefore, we hypothesize that “Tenacibaculum dicentrarchi chronic infection triggers a type 2 immunity (Th2/M2) IL-4/13/ IL-10+ phenotype in head kidney and spleen of Atlantic salmon, increasing the secretion of anti-inflammatory cytokine IL-10, which favor and increase the severity of Piscirickettsia salmonis coinfection”. The general objective of the proposal is to demonstrate that a chronic infection of Tenacibaculum dicentrarchi causes in Atlantic salmon a status of head kidney and spleen immunosuppression presented an IL 4/13/ IL-10+ phenotype and increasing the mortality provoked by Piscirickettsia salmonis coinfection. To demonstrate the hypothesis, three specific objectives are proposed. First specific objective is “Characterize the immunological response of the single infection of T. dicentrarchi and coinfection with T. dicentrarchi and P. salmonis in Atlantic salmon under field conditions during outbreak seasons”. For this specific objective, we designed the Trial 1: Field sampling in open-sea cages during a single infection of T. dicentrarchi in winter and a coinfection with T. dicentrarchi and P. salmonis in spring. The analysis of the immune response will be through gene expression by RT-PCR and proteins by ELISA and western blotting. Then, the second objective propose is “Verify the type 2 immunity (Th2/M2) IL-4/13/ IL-10+ phenotype elicit by a T. dicentrarchi infection in Atlantic salmon under controlled conditions of laboratory”. To accomplish this goal we designed the Trial 2: A single infection challenge with T. dicentrarchi in Atlantic salmon in laboratory conditions in order to better characterize the immune response at a cellular level by flow cytometry and a molecular level by RNA-seq, RT-PCR and protein level. The final specific objective is “Characterize at the immunological level the development and severity of P. salmonis infection in Atlantic salmon infected by T. dicentrarchi under controlled conditions of laboratory”. To achieve this objective we designed the Trial 3: A coinfection with T. dicentrarchi and P. salmonis in Atlantic salmon in laboratory conditions with the respective single infection controls of each pathogen and posterior analysis by molecular and protein level. The expected results are: 1) The characterization of the immune response at functional level of the single infection of T. dicentrarchi and the coinfection of T. dicentrarchi and P. salmonis in Atlantic salmon in open-sea cages; 2) Verification that T. dicentrarchi triggers a type 2 immunity (Th2/M2) with an increase in the secretion of cytokine IL-10 demonstrated through transcript, protein, and cellular analysis in laboratory conditions that will let us a better resolution of the immune response characterization in comparison with the field conditions; 3) Characterization of the development of a more harmful P. salmonis infection due to the weaker health status on Atlantic salmon produced by of T. dicentrarchi, which means a higher bacterial load of P. salmonis and mortality rate in coinfected fish with T. dicentrarchi and P. salmonis. The results obtained in this research will provide animal health information to improve the productive management of salmonids and contribute to the knowledge of the health status of Atlantic salmon in the context of the two main pathogens affecting Chilean aquaculture nowadays.

Los problemas en la teoría de parada óptima se aplican a muchas situaciones en la vida. Por ejemplo, cuando decidimos mudarnos, tenemos que determinar cuándo dejar de buscar una casa; al estacionar el auto, debemos decidir cuándo tomar un lugar disponible en lugar de seguir buscando uno mejor; cuando ocurre un terremoto, el gobierno debe decidir cuándo dejar de observar y comenzar a evacuar a la población, etc. Aunque algunas de estas decisiones deben tomarse con más frecuencia que otras y el riesgo involucrado no es el mismo en todas las situaciones, la idea detrás de todos estos problemas es similar: un tomador de decisiones observa un proceso que evoluciona en el tiempo e implica cierta aleatoriedad. Basándose solo en lo que se conoce, se debe tomar una decisión que maximice la recompensa o minimice el costo. Entonces, la pregunta principal aquí es: ¿cuándo deberíamos detenernos? Responder a esta pregunta es importante para tomar buenas decisiones. Sin embargo, no siempre es fácil debido a la información incompleta sobre el futuro. Esto llevó al surgimiento de un subcampo de la teoría de probabilidad, la teoría de parada óptima, que tiene como objetivo mejorar las probabilidades de tomar una buena decisión. El objetivo de este proyecto es estudiar diferentes problemas en este campo, modelándolos y obteniendo resultados teóricos así como también estudiar el impacto de los resultados en la práctica.

The brain is an energy intensive organ that requires a robust supply of nutrients and oxygen. The vasculature irrigating the brain is a huge and complex network of blood vessels fulfilling this requirement, while also protecting the neural tissue from blood-borne toxic substances. This regulated nutrient supply is accomplished by the formation of a highly selective molecular barrier, termed the blood-brain barrier (BBB). Dysfunction of the BBB or malformations of the vascular network are associated with pathological conditions that impair brain function, and can lead to death. Thus, appropriate morphogenesis and establishment of the brain vasculature is necessary for a healthy life. The brain vasculature forms during intrauterine development, matching brain growth in this same period. Anatomically, blood vessels grow first surrounding the brain primordium and then penetrate the parenchyma until they vascularize the periventricular zone. The molecular regulation of this patterned growth is not completely understood. Several signaling pathways are known to be involved in brain angiogenesis, including WNT, TGF-β, Hh, and NOTCH, which differentially regulate vascular growth. Recently, cholesterol has been shown to modulate angiogenic growth in other vascular beds by regulating the activity of the NOTCH pathway, suggesting that cholesterol levels could influence developmental angiogenesis in the brain. Interestingly, cholesterol is also required for signal transduction of the Hh pathway. In preliminary in vitro experiments, we have observed that brain endothelial cells activate an angiogenic program after cholesterol depletion. Here, we will extend those studies to in vivo models to determine the role of cholesterol in developmental brain angiogenesis. We propose that an increase in vascular cell cholesterol activates NOTCH and attenuates Hh signaling pathways, restricting sprouting angiogenesis and blood-brain barrier formation in mouse embryo brain vasculature. To test this hypothesis, we will study mouse embryos with altered cholesterol levels by dietary, pharmacological, and genetic manipulations. We expect these manipulations to induce a reduction or an increase in cholesterol levels in the brain vasculature during embryonic development, which we will evaluate by measuring cholesterol content in isolated vascular fragments. In all these models, we will (Specific aim 1) study vascularization in the brain during intrauterine development using immunofluorescence with specific antibodies against endothelium proteins. In addition, we will measure the levels of transcript and proteins of general key regulators of angiogenesis in isolated vascular fragments, using qPCR and Western blot. We will (Specific aim 2) also evaluate the state of the BBB in the brain vasculature of these models at a fetal stage when the barrier is already formed and functional. For this, we will use immunofluorescence to detect the presence of marker proteins of the BBB in vascular fragments, and we will measure their levels by Western blot. Further, we will test the functionality of the barrier by injecting a fluorescent tracer and evaluating its extravasation in the brain. Finally, we will (Specific aim 3) determine the activation of the NOTCH and Hh pathways in the brain vasculature of the models at the stage of maximal angiogenesis. We will use qPCR and Western blot to measure the levels of marker genes and proteins for these two pathways in vascular fragments, and Proximity Ligation In Situ Hybridization in tissue sections to evaluate the transcript levels of those markers in situ. We expect that the different models of dietary, pharmacological, and genetic interventions will increase or reduce cholesterol levels in the brain vasculature. These changes are expected to correlate with opposing effects on angiogenesis in the brain during development (i.e. low cholesterol will increase angiogenesis, while high cholesterol will inhibit it). In the same way, we expect that distinct cholesterol levels will have opposing effects on the integrity of the BBB. These changes in angiogenesis and BBB function are expected to be associated with concomitant disruption of the NOTCH and Hh pathways. In summary, in this proposal we aim to cover a knowledge gap regarding the role of cholesterol in the regulation of developmental angiogenesis in the brain. These experiments may uncover new mechanisms driving vascular growth and barrier establishment in the brain, which could lead to new strategies for the prevention and treatment of pathologies involving the brain vasculature.

Este proyecto fue adjudicado, pero renunciado por el investigador principal

Listeria monocytogenes (Lm) is a foodborne pathogen that causes listeriosis, a severe invasive disease, with mortality rates as high as 30 %. This pathogen has caused several foodborne outbreaks and product recalls worldwide, with significant economic consequences for the food industry. Lm can resist many stresses used in food-processing environments (FPE) to control bacterial growth. Biofilm formation is another strategy that allows Lm to persist in FPE and contaminate foods. In natural environments, biofilms often consist of mixedspecies communities with dynamic interactions between different species. The structure and persistence of these biofilms are determined by community compositions, cooperative development, genomic background, environment-responsive gene expression, and the material on which the biofilm forms, among others. The design of materials with anti-bacterial and anti-biofilm properties is an emerging strategy to control the presence of foodborne pathogens in the FPE. Smart surfaces with on-demand antimicrobial protection through “physical” activation are ideal for this application. For instance, conductive polymers and piezocatalytic materials generate reactive oxygen species (ROS) by photothermal or mechanical stimulus, respectively. To further advance in the design of effective ROS-releasing antibiofilm materials, it is essential to understand the microbial interactions occurring in biofilms and how molecular mechanisms are regulated by the pathogen under ROS-based stress conditions. In this study, we hypothesize that “The efficacy of ROSreleasing antibiofilm materials can be modulated based on knowledge of the interactions between Lm isolates and other species on biofilms formed under FPE simulated conditions and by identifying specific molecular mechanisms regulated by Lm isolates that persist under these environmental conditions.” This research will take an interdisciplinary approach, integrating knowledge from different fields (microbiology, molecular biology, chemistry, and materials science) to better understand the mechanisms involved in Lm biofilm formation under FPE conditions and use this information to design efficient materials to control bacterial contamination. Our main aim is “to investigate the interplay between Lm and other bacteria in ROS-releasing antibiofilm materials under FPE conditions and identify the molecular mechanisms that Lm activates.” Specific aim-1 To define the best condition for tailor-made ROS generation in conductive polymers and polymer/ZnO composites able to control Lm mixed biofilms. We will design and assess the ROS generation capabilities of conductive polypyrrole (PPy) and piezocatalytic polymer/ZnO materials. We currently have a collection of 300 Lm strains isolated from various sources. Approximately 50% of these strains have had their whole genomes sequenced. The effect of ROS-releasing materials on cell adhesion and biofilm formation will be tested for Lm strains in the presence of other bacterial species isolated from FPE (mixed biofilm) at 8ºC. We will identify the best technical conditions of the ROS-releasing material to control or reduce Lm biofilm formation. In addition, we will know if the Lm strains have different levels of tolerance to ROS under the conditions that we will test. Specific aim-2: To identify Lm genetic features associated with tolerance on ROS-releasing materials. Additional Lm strains from our collection will be sequenced. We will also have access to Lm strains isolated from listeriosis outbreaks with their genome sequences. We will analyze the genomes of Lm strains exhibiting varying levels of biofilm tolerance on ROS-releasing materials under FPE conditions. We will evaluate the association between genomic elements (virulence genes, resistance determinants, and other genomic variations) and the tolerance levels of the ROS-releasing materials to identify new genomic elements associated with biofilm formation. Specific aim-3: To identify molecular programs and ecological roles activated by Lm in response to ROS-releasing material under FPE conditions One material with adjusted photothermal and mechanical ROS generation will be selected to evaluate the global transcriptional response of Lm isolates able to tolerate ROS-releasing materials. We will evaluate this response considering FPE conditions: low temperature and mixed biofilms. In this way, we will identify if some Lm isolates activate specific molecular mechanisms that are associated with the persistence/or higher tolerance to ROS-releasing materials under FPE conditions. Expected outcomes: This research will contribute to advancing the antibiofilm material design, understanding Lm genetic characteristics, and identifying molecular mechanisms activated under conditions used in food processing areas, thus promoting improved food safety and industry practices.

This proposal ultimately seeks to provide information to guide conservation and management policies for Myostemma species, and a model to assess the vulnerability to GCC in other organisms of the highly endemic and threatened CWRVF biodiversity hotspot. This project will generate the first complete genome sequence for Amaryllidoideae, which will have a global impact by enabling genome-based evolutionary, breeding, biochemical, and pharmaceutical research.

La colaboración entre nuestros grupos busca formar una alianza para fortalecer la investigación científica y tecnológica y la formación de capital humano calificado en Genómica, Biología de Sistemas y Biotecnología, para mejorar la productividad de especies agrícolas y acuícolas en un escenario de cambio climático, vinculándonos con actores y necesidades del sector productivo. Con esta propuesta, buscamos crear un polo nacional de investigadores capacitados en las últimas herramientas y tecnologías que siente la bases para la postulación conjunta a proyectos asociativos y/o de investigación aplicada e interdisciplinaria en el corto plazo, la producción de artículos científicos y propiedad intelectual y la formación de excelencia de las futuras generaciones.

Basal FB210005

Según Tan y colaboradores (2020), la enseñanza de las matemáticas en la Educación Especial ha tendido hacia un carácter reparador que ha restringido el acceso al conocimiento, relegando a sus estudiantes a bajas expectativas, es decir, “formas deshumanizadas del aprendizaje matemático” (p. 22). Un factor clave para la superación de esta problemática es el conocimiento del profesor que enseña matemáticas, entendido como el conocimiento profesional necesario para realizar las tareas recurrentes al enseñar matemáticas, el que se ha mostrado como crítico para fomentar el aprendizaje de las matemáticas escolares (e.g. Blömeke et al., 2022). No obstante, este hecho tiene una particularidad cuando se trata de la enseñanza a estudiantes ciegos. Por ejemplo, algunos autores señalan que el conocimiento de este colectivo de profesores es enseñar a los estudiantes estrategias de cálculo especializadas, i.e., signografía matemática, el ábaco japonés Soroban o la máquina de escribir braille (Brawand y Johnson, 2016). Este foco en el cálculo estaría superado por la complementariedad que debiese darse con el profesor de aula regular, sin embargo, en las escuelas especiales para estudiantes ciegos, las y los encargados son educadores especiales. En este sentido, existe muy poca literatura respecto a cuáles son las estrategias más adecuadas para enseñar a estos estudiantes (Klingenberg et al., 2019) y particularmente, respecto a los conocimientos de educadores que los acompañan en estos procesos (Piñeiro y Calle, en prensa). Por lo anterior, este proyecto tiene como meta contribuir al aprendizaje de las matemáticas de estudiantes ciegos de educación básica, de una escuela especial. Para ello, ponemos el foco la caracterización del conocimiento matemático para la enseñanza sobre números y operaciones en aulas de estudiantes ciegos. Las preguntas que guían esta investigación son: ¿qué conceptos y habilidades moviliza el profesor de educación de personas ciegas cuando enseña el sistema de numeración y las operaciones aritméticas?, ¿qué uso realizan los profesores del conocimiento matemático para la enseñanza en sus prácticas? Estas preguntas se operativizan a través de un objetivo general que persigue “caracterizar el conocimiento matemático para la enseñanza que ponen en juego los profesores de educación especial de estudiantes ciegos al enseñar números y operaciones”. Para su consecución se ha diseñado un estudio cualitativo-exploratorio que se centra en el conocimiento matemático para la enseñanza y el uso que dan a este conocimiento. Se realizará un estudio cualitativo siguiendo un videobased approach (Widjaja et al., 2019). Además, se realizarán entrevistas pre-grabación de la clase que indaguen, mediante las categorías del MTSK, aspectos del diseño de la clase. Además, entrevistas posteriores a las clases para revisar, en conjunto, episodios específicos de las clases que otorguen mayor claridad a las decisiones tomadas en el aula. La racionalidad de focalizar en este tipo de escuela, tiene relación con que en la gran mayoría de escuelas especiales no existe la posibilidad de que profesores de educación especial trabajen colaborativamente con profesores de asignatura. Así, las y los educadores especiales deben hacerse cargo de la enseñanza de las matemáticas a estos niños y niñas sin haber sido formados en ello (Piñeiro y Calle, 2023).