Universidad Mayor

Aridification is known to disrupt soil biogeochemical cycles by altering the stoichiometry of key elements, such as carbon (C), nitrogen (N) and phosphorus (P). However, how soil microbiome metabolically responds to these imbalances, and the resulting implications for terrestrial ecosystem services, remain virtually unknown. By analyzing soil samples from 200 ecosystems across globally distributed biomes, our results revealed an overall microbial genomic adjustment to elemental imbalances driven by aridity. Genes involved in microbial anabolism were promoted with aridification, whereas those associated with catabolism were suppressed. Thus, while genes encoding extracellular enzymes responsible for the degradation of litter and organic matter decreased, genes related to RNA transcription and the synthesis and transport of intracellular proteins essential for microbial resistance and growth increased. Collectively, our findings highlighted that aridity-driven soil elemental imbalances are strongly associated with shifts in soil microbial metabolism from catabolism to anabolism, reflecting a microbial survival strategy that prioritizes growth over energy and nutrient acquisition under global-scale aridification.

The sixth mass extinction and the ongoing biodiversity and climate crises demand urgent action from ecologists and environmental scientists (EESs). Despite their critical role in addressing these challenges, EESs face unclear professional responsibilities towards society, local communities and ecosystems. The 2024 ANdiNA workshop was held in Conguillío National Park in Chile, within Wallmapu the ancestral land of the Mapuche people. It gathered global EESs to explore the roles, obligations and accountability of professionals in this field. The discussions focused on the evolving responsibilities of EESs amidst the environmental crises, as well as the need for clearer frameworks to guide their actions. Key questions included the scope of EESs' professional activities, how their obligations should adapt during times of crisis and whether they should be held accountable for scientific mistakes that lead to negative societal outcomes. The workshop explored the potential for creating a codified framework, such as an oath or manifesto, to clarify EESs' professional responsibilities. Participants highlighted the importance of integrating financial, intellectual, ethical and institutional dimensions in defining these roles, particularly in how EESs engage with local communities and society. Emerging themes included the need for a shared framework to align EESs' actions, exemplified by the Conguillío Statement, which encourages collaboration, inclusivity and ethical engagement with communities, especially Indigenous ones. The workshop also emphasised the importance of solution-orientated, transformative research and advocacy, calling for a shift in how EESs approach their roles as agents of change. By critically reflecting on their responsibilities, the workshop provided a foundation for re-imagining the role of EESs in the face of global environmental crises, urging systemic, collaborative approaches to safeguarding both nature and humanity.

PURPOSE Hodgkin lymphoma (HL) is classified as the first malignancy to be cured by a combination of chemotherapy and radiotherapy. However, the life expectancy of HL survivors is hampered by the occurrence of late adverse events, including second malignant neoplasms (SMNs) and cardiovascular diseases (CVDs). PATIENTS AND METHODS We investigated the causes of death in a cohort of 1,435 patients over age 15 years treated at 18 different public cancer centers in Chile. RESULTS After a median follow-up of 19 years (0-37), the 5-year overall survival improved from 64% in the cohort 1985-1994 to 81% in the cohort 2009-2014 ( P < .001). HL was the main cause of death in the first 10 years after treatment, whereas SMN and CVD risk peaked 10-15 years and remained raised for 30 years or longer. Cumulative incidence of deaths (CIDs) due to SMNs resulted significantly higher in patients treated with cyclophosphamide, vincristine, procarbazine, prednisone (MOPP)/MOPP-like regimens over doxorubicin, bleomycin, vinblastine, dacarbazine. CIDs due to CVDs increased from 0.4 to 4.1 at 5 and 20 years, respectively. CONCLUSION HL survivors continue to have a reduced life expectancy due to an increased risk of dying of SMNs and/or CVDs, although it was lower among patients treated in the most recent calendar period studied (2002-2014).

This chapter aims to explore the multifaceted experiences of migrants residing in transient camps and those experiencing homelessness in Latin America and the Caribbean. Notwithstanding the lack of reliable data, migrants in the region face significant challenges throughout their journeys and upon arrival. The complexity of the migration and displacement journeys in Latin America, including south-south flows (e.g., Venezuela-Colombia) and crossing through dangerous geographic points, such as the Darien Gap, leave people in uncertain and precarious housing situations for unlimited and unknown periods of time. Furthermore, shelters experience overcrowding and encounter challenges in accommodating the influx of displaced population, many of them children who arrive unaccompanied or separated from their parents. The precarious conditions of migrants in transient camps and those experiencing homelessness represent a critical humanitarian issue that requires in-depth research. To address this issue, multiple stakeholders must collaborate to obtain consistent data, advocate for migrants’ rights, and provide effective interventions, including promoting respect for human rights, ensuring access to essential services, and providing safe and legal migration pathways.

Background The agropastoral communities of Coquimbo, Chile, are characterised by their goat herding-based livelihoods, admixed ancestry, and transhumant mobility. Aim To explore the impact of these features on genetic diversity and interactions with neighbouring populations. Subjects and methods Genotypic polymorphisms of 15 STRs were analysed in 466 individuals from 15 communities. Forensic parameters were estimated. Genetic structure was assessed using RST, Nei’s distances, MDS, dendrograms, and STRUCTURE, with 23 reference populations from Chile, South America and globally. Results A total of 158 alleles were observed, with frequencies ranging from 0.0011 to 0.5172. CSF1PO, D18S51, and Penta E showed deviation from Hardy-Weinberg equilibrium. The panel demonstrated high forensic performance (combined power of discrimination CPD > 0.999999999, combined power of exclusion CPE = 0.99999713817). No clear genetic structure was found within the Coquimbo communities. Regionally, Coquimbo clustered with northern Chile and north-west Argentina. Globally, it resembled other South American admixed populations, slightly differentiated from those from other regions. Conclusions The STRs analysed show high forensic potential, low genetic structure within the agropastoral communities, and important similarities with populations in northern Chile and north-west Argentina, supporting the relevance of trans-Andean mobility in shaping their genetic landscape.

This work highlights the critical role of synthesis conditions in tuning the properties of carbon dots (CDs) for optimized performance in biomedical applications, offering valuable insights into the design of these carbon nanomaterials. Although various synthesis methods and carbon sources have been explored for CD production, few studies have investigated how synthesis temperature modulates and optimizes their physicochemical attributes. In this study, cationic CDs derived from poly(ethylene imine) (PEI) and chitosan (CS) were synthesized using a microwave-assisted hydrothermal method at different temperatures to explore this aspect. It was found that higher carbonization temperatures during the hydrothermal process resulted in smaller, more photoluminescent CDs. This increase in temperature significantly enhanced the biological interactions of the CDs, demonstrating notable biocompatibility. In contrast, the lowest hydrothermal temperature enhanced cytotoxic effects against the Gram-positive pathogen Staphylococcus aureus under light exposure. Furthermore, gastric cancer (AGS), colon cancer (HT-29), cervical cancer (HeLa), prostate cancer (PC-3), and breast epithelial (MCF-10) cell lines showed cytotoxicity that was dependent on the CDs synthesized at different temperatures.

Background/Objectives: Osteoarthritis (OA) is a leading cause of mobility impairment in older adults, yet few studies have explored exergames (EXGs) as a complementary therapy for knee and/or hip OA (KOA/HOA). This study evaluated the effects of integrating EXGs into conventional therapy (CT) on functional mobility. Methods: Sixty participants were randomized into an EXG/CT group or a CT-only group. The interventions lasted 10 weeks (3 sessions/week), and the EXGs were selected from the interactive game Ring Fit Adventure (Nintendo Switch®, Kyoto, Japan). Results: Functional mobility (Timed Up and Go test) significantly improved in the EXG/CT group but not in the CT group. Additionally, lower-limb strength and aerobic endurance increased in the EXG/CT group. No adverse events were reported, and the adherence was high. Conclusions: These findings support EXG-based interventions as a viable complement to CT. Future studies should design OA-specific EXGs and include patient subgroups to expand the impact of interventions using virtual systems.

Cells move directionally along gradients of substrate stiffness — a process called durotaxis. In the situations studied so far, durotaxis relies on cell-substrate focal adhesions to sense stiffness and transmit forces that drive directed motion. However, whether and how durotaxis can take place in the absence of focal adhesions remains unclear. Here, we show that confined cells can perform durotaxis despite lacking focal adhesions. This durotactic migration depends on an asymmetric myosin distribution and actomyosin retrograde flow. We propose that the mechanism of this focal adhesion-independent durotaxis is that stiffer substrates offer higher friction. We put forward a physical model that predicts that non-adherent cells polarise and migrate towards regions of higher friction — a process that we call frictiotaxis. We demonstrate frictiotaxis in experiments by showing that cells migrate up a friction gradient even when stiffness is uniform. Our results broaden the potential of durotaxis to guide any cell that contacts a substrate, and they reveal a mode of directed migration based on friction. These findings have implications for cell migration during development, immune response and cancer progression, which usually takes place in confined environments that favour adhesion-independent amoeboid migration.

Argonaute (AGO) proteins bind to small RNAs to induce RNA interference (RNAi), a conserved gene regulatory mechanism in animal, plant, and fungal kingdoms. Small RNAs of the fungal plant pathogen Botrytis cinerea were previously shown to translocate into plant cells and to bind to the host AGO, which induced cross-kingdom RNAi to promote infection. However, the role of pathogen AGOs during host infection stayed elusive. In this study, we revealed that members of fungal plant pathogen B. cinerea BcAGO family contribute to plant infection. BcAGO1 binds to both fungal and plant small RNAs during infection and acts in bidirectional cross-kingdom RNAi, from fungus to plant and vice versa. BcAGO2 also binds fungal and plant small RNAs but acts independent from BcAGO1 by regulating distinct genes. Nevertheless, BcAGO2 is important for infection, as it is required for effective pathogen small RNA delivery into host cells and fungal induced cross-kingdom RNAi. Providing these mechanistic insights of pathogen AGOs promises to improve RNAi-based crop protection strategies.

(1) Background: The variability and trend in harvest dates of table and Pisco grapes have been scarcely studied. This can be closely influenced by bioclimatic indices since they account for the interactions between climatic factors and vine phenology. Understanding the environmental factors influencing harvest timing has become increasingly critical to perform specific viticultural practices. (2) Methods: The aim of this research was to evaluate the influence of bioclimatic indices on variability and trend of harvest date from the 2002–2003 to 2017–2018 seasons in Flame Seedless, Thompson Seedless, Muscat of Alexandria, and Moscatel Rosada growing in Northern Chile. (3) Results: The harvest date of Flame Seedless advanced significantly with an increasing Growing Season Temperature (GST) (from 1 October to 31 December), while Thompson Seedless showed a significant advancement in harvest date with rising the Maximum Springtime Temperature Summation SONmax (from 1 September to 30 November) values. Similarly, the harvest date of Muscat of Alexandria was significantly earlier with higher Heliothermal Index (HI) (from 1 July to 31 January and from 1 August to 30 April) values, whereas Moscatel Rosada exhibited a significant advancement in harvest date as the GST (from 1 July to 31 December and from 1 July to 31 January) increased. The trend in the harvest date of Thompson Seedless was statistically significant, reaching a coefficient of determination of 0.42. (4) Conclusions: Understanding the influence of bioclimatic indices on harvest date in long-term periods is critical in the context of climatic variability since producers can make more informed decisions to optimize grape quality and maintain sustainability in production systems.

Understanding how plants survive extreme conditions is essential to breeding resilient crops. Cistanthe longiscapa, which flourishes in the Atacama Desert, provides a rare glimpse into plant resilience. To uncover the genetic basis of its stress tolerance, we investigated the ecophysiological and transcriptomic responses of C. longiscapa from 3 sites with low but different precipitation levels. Ecophysiological analyses were performed on samples collected in the field at dusk and dawn, which are crucial stages in crassulacean acid metabolism (CAM), a water-efficient type of photosynthesis. Additional transcriptomic analysis allowed us to evaluate CAM intensity in C. longiscapa and identify changes in the molecular signature of these plants. Our results show that C. longiscapa displays considerable ecophysiological trait response variation across the 3 sites, including variations in markers such as nocturnal acid accumulation, isotopic carbon ratio, and succulence, among others. Analysis of gene expression patterns revealed differences among plants exhibiting varying intensities of CAM photosynthesis and identified key molecular signatures associated with their ecological strategies. Additionally, genes related to stress responses, plastid activities, and circadian rhythm show contrasting expression levels between strong and weak CAM plants, and this expression profile is shared with other CAM plants under stress. Our findings demonstrate that C. longiscapa is a valuable resource for identifying genes involved in the transition between different CAM intensities. This may lead to the discovery of genes that enhance plant tolerance to stressful environments.

A bstract We discuss an extension of the standard model with a real scalar triplet, T , including non-renormalizable operators (NROs) up to d = 6. If T is odd under a Z 2 symmetry, the neutral component of T is a good candidate for the dark matter (DM) of the universe. We calculate the relic density and constraints from direct and indirect detection on such a setup, concentrating on the differences with respect to the simple model for a DM T with only renormalizable interactions. Bosonic operators can change the relic density of the triplet drastically, opening up new parameter space for the model. Indirect detection constraints, on the other hand, rule out an interesting part of the allowed parameter space already today and future CTA data will, very likely, provide a decisive test for this setup.

Understanding the role of pressure anisotropy and dissipation is crucial for modelling compact objects’ internal structure and observable properties. In this work, we reinterpret local pressure anisotropy in relativistic stellar structures as an additional contribution to the energy density. This perspective enables the formulation of anisotropic equations of state for self-gravitating systems by incorporating anisotropy as a fundamental component. We demonstrate that this approach yields more realistic stellar models that satisfy key physical constraints, including mass-radius relationships and stability conditions. Our results are compared with observational data, particularly the inferred compactness of pulsars PSR J0740+6620 and PSR J0030+0451, showing that both anisotropic and isotropic models can describe these objects. Additionally, we examine the influence of dissipation – such as temperature gradients – on radial pressure, demonstrating that it can be modelled similarly to anisotropy. This interpretation allows the transformation of dissipative anisotropic models into equivalent non-dissipative isotropic configurations.

Osteoarthritis (OA) of the temporomandibular joint (TMJ) is a progressive disease characterized by the progressive destruction of the internal surfaces of the joint. Certain epigenetic biomarkers have been detected in TMJ-OA. We summarized the available evidence on the epigenetic biomarkers in TMJ-OA. There is an increase in the expression of non-coding RNAs related to the degradation of the extracellular matrix, chondrocyte apoptosis, and proinflammatory cytokines, while there is a decrease in the expression of those related to COL2A1, as well as the osteogenic and chondrogenic differentiation of mesenchymal stem cells. Certain methylated genes and histone modifications in TMJ-OA were also identified. In the early stage, DNA methylation was significantly decreased; that is, the expression of inflammation-related genes such as TNF and genes associated with extracellular matrix degradation, such as Adamts, were increased. While in the late stage, there was an increase in the expression of genes associated with the TGF-β and MAPK signaling pathway and angiogenesis-related genes. Although research on the role of epigenetic markers in TMJ-OA is still ongoing, the results here contribute to improving the basis for the identification of accurate diagnostic and prognostic markers and the development of new therapeutic molecules for the prevention and management of TMJ-OA. It also represents a significant advancement in elucidating its pathogenesis.

In this study, we investigated the influence of environmental temperature and immune challenge on organ and body mass in juvenile degus (Octodon degus). Using an experimental design with two temperature treatments (15 °C and 30 °C) and a lipopolysaccharide (LPS)-induced immune challenge, we measured the mass of key organs (kidney, heart, liver, spleen, lung) as well as body mass. Our results showed that temperature alone significantly affected kidney, heart, lung, and body mass, with individuals reared at 30 °C exhibiting larger organs and greater body mass, consistent with thermoneutral conditions. Immune challenge with LPS primarily affected lung mass, with challenged individuals showing larger lungs regardless of temperature. However, no significant changes were observed in spleen or liver mass, and no interactions between temperature and immune challenge were detected. These findings suggest that temperature-driven developmental plasticity plays a dominant role in shaping organ and body traits, while immune activation induces organ-specific responses. Our results highlight the importance of environmental temperature in shaping physiological traits and raise questions about the long-term effects of immune challenges and temperature interactions on wildlife health and fitness.

The endangered green sea turtle (Chelonia mydas; hereafter C. mydas) plays a crucial role in maintaining the balance of marine ecosystems. However, its populations are highly vulnerable to various threats, including marine pollution. Rapa Nui (Easter Island), an isolated location in the southeastern Pacific, provides vital foraging habitats for both morphotypes of Pacific C. mydas (black and yellow). In this study, we examined the demographic structure (morphotype, life stage, sex) and health status (based on blood analytes and mercury-Hg concentration) of C. mydas on Rapa Nui during 2018 and 2023. Turtles from various life stages and sexes were observed, with a predominance of yellow morphotype juveniles, likely recently recruited or emerging from brumation. Haematological analyses revealed low levels of several key analytes (e.g. cholesterol, calcium, phosphorus, total protein, globulins), suggesting poor nutritional status, potentially related to the brumation process, limited food availability or poor food quality in the region. Alterations in both red and white blood cell lines, including anaemia and lymphopenia, indicate ongoing inflammatory states and infections, consistent with clinical observations. Rapa Nui turtles exhibited some of the highest blood Hg concentrations globally. Abnormalities in blood profiles, along with correlations between various analytes and blood Hg concentrations, suggest altered immune function and probable renal and liver dysfunction, likely resulting from both natural and anthropogenic sources of this heavy metal. Additionally, a very high body condition index in turtles with carapace lesions suggests a negative impact from human food subsidies in local bays, particularly from high-trophic-level fish, which may also serve as a pathway for Hg accumulation, both for the turtle aggregation and the human population. Our findings underscore the urgent need for long-term mercury monitoring and turtle movement studies to identify pollution sources, inform effective conservation strategies for this endangered species, and address potential public health concerns on this remote Pacific island.

An education oriented towards learning must necessarily include assessment techniques and instruments that effectively achieve this goal. Currently, assessment has become a crucial element, leading to the promulgation of legal regulations to govern it. This study aimed to explore the perceptions of assessment in three Chilean universities among faculty members vs. practicum students from two cohorts of Chilean Initial Teacher Education in Physical Education (ITEPE) from two cohorts from subsequent moments, with a difference of four years. The study followed a quantitative, cross-sectional, and comparative approach and the sample consisted of a total of 458 participants, including 1st Group: n = 162 practicum students (S1) 2019–20 (M = 22.5, SD = 3.1) and 44 faculty members (FM1) from the same cohort (M = 42.3, SD = 11.2) vs. 197 practicum students (S2) 2023–24 (M = 23.6, SD = 2.2) and 55 faculty members (FM2) from this cohort (M = 40.4, SD = 10.4). Data were collected using the “Questionnaire for the Study of the Assessment System”. The results revealed significant differences between students and faculty regarding the perception of the use of assessment instruments in ITEPE. The 2023–24 cohort students perceived a greater presence of portfolios compared to their peers from four years ago, while faculty from the latest cohort indicated a perception of higher use of traditional exams. In conclusion, it can be observed that decision-making predominantly falls on the faculty, as evidenced by discrepancies regarding feedback and student participation in grade determination. This reinforces the idea that the process remains teacher-centered.

Cold climate viticulture is challenged by climatic variability, including increased frost risk, shorter growing seasons, and unpredictable weather events that impact vine productivity and grape quality. Global warming is altering traditional viticulture zones, prompting the exploration of new regions for grape cultivation, the selection of climate-resilient cultivars, and the implementation of adaptive practices. This review synthesizes recent advances in adaptive viticulture practices and plant growth regulator applications, highlighting novel molecular and physiological insights on cold stress resilience and berry quality. Key strategies include delayed winter pruning to mitigate frost damage, osmoprotectant application to improve freeze tolerance, and canopy management techniques (cluster thinning and defoliation) to enhance berry ripening and wine composition. Their effectiveness depends on vineyard microclimate, soil properties and variety-specific physiological response. Cover cropping is examined for its role in vine vigor regulation, improving soil microbial diversity, and water retention, though its effectiveness depends on soil type, participation patterns, and vineyard management practices. Recent transcriptomic and metabolomic studies have provided new regulatory mechanisms in cold stress adaptation, highlighting the regulatory roles of abscisic acid, brassinosteroids, ethylene, and salicylic acid in dormancy induction, oxidative stress response, and osmotic regulation. Reflective mulch technologies are currently examined for their ability to enhance light interception, modulating secondary metabolite accumulation, improving technological maturity (soluble solids, pH, and titratable acidity) and enhancing phenolic compounds content. The effectiveness of these strategies remains highly site-specific, influenced by variety selection and pruning methods particularly due to their differences on sugar accumulation and berry weight. Future research should prioritize long-term vineyard trials to refine these adaptive strategies, integrate genetic and transcriptomic insights into breeding programs to improve cold hardiness, and develop precision viticulture tools tailored to cold climate vineyard management.