Proyectos

Ocean Island Volcanoes (OIVs) and seamounts are one of the most common, prominent and rapidly formed but least studied (from a geological/volcanological point of view) features on Earth. OIVs, which represent only the summit section of a much larger volcanic edifice rising up from the sea floor, are highly vulnerable to geological hazards such as volcanism, seismic activity, mass wasting (caldera formation), landslides and rockfalls, and tsunamis. Specifically, a volcanic eruption on an OIV can mainly have a substantial impact on the local population, infrastructure and economy. It is then essential understand the characteristic behaviour and the ages of the recent eruptions of the volcano to enhance the capacity to identify future geological hazard processes such as eruptions, tsunamis, etc. In other words, to forecast how a volcano will behave, it is essential to identify, map and analyse the deposits from past eruptions and determine the ages of those deposits. However, this becomes more challenging on Ocean Island Volcanoes that have not experienced recent eruptions, such as Easter Island (Chile), but which may still pose a significant risk of future eruption. This proposal focuses on Easter Island (Rapa Nui or Isla de Pascua), an isolated southeast Pacific island with 7.750 inhabitants, that receives more than 100.000 tourists per year. This island has been catalogued as one of the 92 active volcanos of Chile by the Chilean mining and geological service, occupying the 46th position in its Volcanic Risk ranking. It was included taking into account the recent activity focused on Terevaka volcano and its peripheral vents and other factors as the population and infrastructures exposure and its high amount of visitors per year. Nevertheless, there is still a lack of robust geochronology and volcano-stratigraphy and morphometry for Easter Island, especially for these most recent eruptions. Therefore, a comprehensive study of its Holocene eruptions regarding their styles, a more accurate age determination, and a well identification of submarine volcanic centres around the island is still pending to evaluate its potential volcanic hazard. The main aim of this project is to identify and study the most recent eruptions of Easter Island, both onshore and offshore. This will allow understanding how and when they took place in terms of volume, diverse morphometric parameters, styles and their ages which will verify if the island is still active. To identify and characterize the style of the most recent eruptions (Holocene- last 11.700 Kyr) on the island it is planned to conduct geomorphologic and morhometryc analyses of subaerial and submarine recent volcanic deposits with and integrated onshore/offshore approach. Also, volcano-stratigraphy for the most recent cones and associated deposits onshore, with special attention to those hydrovolcanic eruptions will be analysed. To determine the number of Holocene eruptions on the island, 14C (for charcoal), 40Ar/39Ar (for rocks) techniques will be used. Moreover, we will identify and date tephras of lacustrine sedimentary records of the Rano Raraku, Rano Kao lakes and the Rano Aroi peat bog related to recent eruptions. A likely future eruption on the island or near its coasts would have negative and serious consequences; therefore, it is essential to undertake this scientific research aimed at improving the knowledge of the processes and their potential impacts. Furthermore, this study will also contribute to understanding the overall evolution of an interoceanic volcanic island whose results can be compared with other more studied OIVs in the world. In addition, this project will support undergraduate and graduate students, for whom this study will comprise most of their dissertation research, being an extraordinary opportunity for them. Moreover, this study will foster ongoing international collaboration, providing a pipeline for future student and faculty exchange, and will promote outreach educational experiences for the community, as well as more specialized seminars.

The world's transition to using cleaner energy sources to address climate change has led to a sharp rise in the demand for base and precious metals. Consequently, discovering new ore deposits to meet this growing demand and prevent supply shortages has emerged as one of the greatest challenges of the 21st century. Discovery of new magmatic-hydrothermal ore deposits can be improved based on a fundamental understanding of the geological processes that control the flux and focusing of ore-constituting elements in the Earth’s crust, and by identifying the differences between the bulk-rock and mineral chemistry of ore-forming and ordinary—barren—granitoids. Large metal anomalies in the Earth’s upper crust, such as porphyry copper-(molybdenum) deposits (PCDs), occur in intimate association with oxidized and water-rich arc magmatism in subduction zones. However, these deposits occur in restricted crustal domains and form in response to specific tectono-magmatic events, indicating that not all arc magmas have the same ore-forming potential. Understanding why only some magmas produced large PCDs while most other arc magmas remain barren is a fundamental scientific question and key to developing efficient exploration strategies. The volatile element composition of arc magmas, including water, sulfur, and halogens such as chlorine and fluorine, as well as their oxygen fugacity, exert a critical control on their ore-forming potential (i.e., ore fertility). These components are not only key to the complexation and transport of ore metals during hydrothermal activity, but also influence the amount of ore metals transported by magmas and the efficiency to which they are transferred from magmas to exsolved fluids. Magmatic differentiation in lower crustal hot zones beneath thick crustal regions is expected to enhance the volatile element budget and oxygen fugacity of evolving magmas that are discharged to the upper crust. This occurs due to the accumulation of incompatible volatile elements during successive cycles of recharge by mafic magmas and crystallization, facilitated by the deeper and hotter conditions beneath thicker arc crusts. As such, an increasingly recognized hypothesis holds that ore-forming magmas display a particularly increased budget of volatile elements and higher oxygen fugacities when compared to barren arc magmas, and that this is largely influenced by the arc crust thickness. The proposed work will test this hypothesis by focusing on the Miocene to Mio-Pliocene magmatism and associated world-class PCD mineralization in the Andes of central Chile. From the Early Miocene to the Mio-Pliocene, the arc segment located between latitudes ~33–34.5° S in the Andes of central Chile has seen a continued increase in crustal thickness and has evolved from being barren in the Early Miocene to producing some of the largest PCDs of the world in the Mio-Pliocene, such as El Teniente and Rio Blanco-Los Bronces. This geological scenario and the spatial and age distribution of the associated outcropping intrusive rocks offer a unique opportunity to investigate the temporal evolution of the volatile composition of magmas and its consequences for ore fertility. The goal of this proposal is to examine, adopting a regional scale perspective, the evolution in the volatile composition and oxygen fugacity of magmas produced in this arc segment and its relationship to magmatic ore fertility, as well as how this may have been influenced by changes in crustal thickness. To achieve this, I will sample an extensive suite of granitoids that represent a continuum from Early Miocene to Mio-Pliocene magmas, including porphyry-forming intrusions. By combining zircon petrochronology, apatite, biotite, and amphibole mineral chemistry, in conjunction with the bulk-rock composition of intermediate to felsic intrusive rocks, I will be able to constrain relative changes in the hydration state, sulfur contents, halogen and oxygen fugacities, as well as in their associated crustal thickness during the evolution of the selected arc segment. This will be done by implementing a combination of cutting-edge analytical techniques, including synchrotron-based sulfur X-ray absorption near edge structure spectroscopy, electron probe microanalysis, (laser ablation) inductively coupled plasma mass spectrometry, and X-ray fluorescence spectrometry. I aim at (1) testing the differences in the volatile composition of barren and ore-forming intrusive rocks; (2) determining whether there is a gradual change in the volatile systematics of magmas during the evolution of the studied arc segment; and (3) analyzing the relationship between variations in crustal thickness and the volatile composition of associated magmas. The results of this proposal will lead to a better understanding of the magmatic controls underpinning the formation of giant PCDs and will provide valuable insights into identifying the differences between the bulk-rock and mineral chemistry of ore-forming and barren granitoids as tools for vectoring mineralized regions.

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.