Tuberculosis (TB) is one of the leading causes of human deaths worldwide caused by infectious diseases. TB infection by Mycobacterium tuberculosis can occur in the lungs, causing pulmonary tuberculosis (PTB), or in any other organ of the body, resulting in extrapulmonary tuberculosis (EPTB). There is no consensus on the genetic determinants of this pathogen that may contribute to EPTB. In this study, we constructed the M. tuberculosis pangenome and used it as a tool to seek genomic signatures associated with the clinical presentation of TB based on its accessory genome differences. The analysis carried out in the present study includes the raw reads of 490 M. tuberculosis genomes (PTB n = 245, EPTB n = 245) retrieved from public databases that were assembled, as well as ten genomes from Mexican strains (PTB n = 5, EPTB n = 5) that were sequenced and assembled. All genomes were annotated and then used to construct the pangenome with Roary and Panaroo. The pangenome obtained using Roary consisted of 2231 core genes and 3729 accessory genes. On the other hand, the pangenome resulting from Panaroo consisted of 2130 core genes and 5598 accessory genes. Associations between the distribution of accessory genes and the PTB/EPTB phenotypes were examined using the Scoary and Pyseer tools. Both tools found a significant association between the hspR, plcD, Rv2550c, pe_pgrs5, pe_pgrs25, and pe_pgrs57 genes and the PTB genotype. In contrast, the deletion of the aceA, esxR, plcA, and ppe50 genes was significantly associated with the EPTB phenotype. Rv1759c and Rv3740 were found to be associated with the PTB phenotype according to Scoary; however, these associations were not observed when using Pyseer. The robustness of the constructed pangenome and the gene–phenotype associations is supported by several factors, including the analysis of a large number of genomes, the inclusion of the same number of PTB/EPTB genomes, and the reproducibility of results thanks to the different bioinformatic tools used. Such characteristics surpass most of previous M. tuberculosis pangenomes. Thus, it can be inferred that the deletion of these genes can lead to changes in the processes involved in stress response and fatty acid metabolism, conferring phenotypic advantages associated with pulmonary or extrapulmonary presentation of TB. This study represents the first attempt to use the pangenome to seek gene–phenotype associations in M. tuberculosis.

Deschampsia antarctica Desv. (Poaceae) is one of the two vascular plants that have colonized the Antarctic Peninsula, which is usually exposed to extreme environmental conditions. To support these conditions, the plant carries out modifications in its morphology and metabolism, such as modifications to the cell wall. Thus, we performed a comparative study of the changes in the physiological properties of the cell-wall-associated polysaccharide contents of aerial and root tissues of the D. antarctica via thermogravimetric analysis (TGA) combined with a computational approach. The result showed that the thermal stability was lower in aerial tissues with respect to the root samples, while the DTG curve describes four maximum peaks of degradation, which occurred between 282 and 358 °C. The carbohydrate polymers present in the cell wall have been depolymerized showing mainly cellulose and hemicellulose fragments. Additionally, a differentially expressed sequence encoding for an expansin-like (DaEXLA2), which is characterized by possessing cell wall remodeling function, was found in D. antarctica. To gain deep insight into a probable mechanism of action of the expansin protein identified, a comparative model of the structure was carried out. DaEXLA2 protein model displayed two domains with an open groove in the center. Finally, using a cell wall polymer component as a ligand, the protein–ligand interaction was evaluated by molecular dynamic (MD) simulation. The MD simulations showed that DaEXLA2 could interact with cellulose and XXXGXXXG polymers. Finally, the cell wall component description provides the basis for a model for understanding the changes in the cell wall polymers in response to extreme environmental conditions.

Deschampsia antarctica Desv. (Poaceae) grows in coastal habitats in the Maritime Antarctic where it is often exposed to sea spray. Salt crystals have been observed on the surface of leaves in plants treated with high NaCl. We investigated if D. antarctica is a salt tolerant species that allows sodium ions to diffuse into the root where a salt overly sensitive (SOS) system extrudes Na⁺ from root cells and facilitates its movement through the xylem up to the leaves. Leaf epidermis, physiological parameters and sodium transporters in D. antarctica plants exposed to NaCl were studied over 21 days. Epidermal scanning electron microscopy showed trichome induction in the leaves of salt treated plants. In addition, salt treated plants showed increased sodium and proline levels with a concomitant increased expression of SOS genes (1 and 3). These results indicate that Na⁺ is taken up by the roots of D. antarctica and transported to the leaves. The sodium flux may be controlled by SOS1 activity. Up-regulation of the SOS1 gene may be involved in the increased sodium levels observed in the leaves of salt treated plants. Trichomes may also be involved in sodium exudation through the leaves under saline conditions.

In this study, bacterial isolates C1-4-7, D2-4-6, and M1-4-11 from Antarctic soil were phenotypically and genotypically characterized, and their antibacterial spectrum and that of cell-free culture supernatant were investigated. Finally, the effect of temperature and culture medium on the production of antimicrobial compounds was investigated. The three bacteria were identified as different strains of the genus Pseudomonas. The three bacteria were multi-drug resistant to antibiotics. They exhibited different patterns of growth inhibition of pathogenic bacteria. M1-4-11 was remarkable for inhibiting the entire set of pathogenic bacteria tested. All three bacteria demonstrated optimal production of antimicrobial compounds at 15 °C and 18 °C. Among the culture media studied, Nutrient broth would be the most suitable to promote the production of antimicrobial compounds. The thermostability exhibited by the antimicrobial molecules secreted, their size of less than 10 kDa, and their protein nature would indicate that these molecules are bacteriocin-like compounds.

Low fermentation temperatures are usually employed to obtain high-quality wines. This is especially interesting for white wine production since it prevents the loss of volatile compounds and a browning appearance; however, available fermentative yeasts do not usually tolerate low temperatures. Therefore, an interesting place to find new yeasts with cryotolerance is the Antarctic continent. From soil samples collected in Antarctica, 125 yeasts were isolated, of which 25 exhibited fermentative activity at 10 °C. After a fingerprinting assay, we classified the candidates into nine isotypes and sequenced internal transcribed spacer regions for their identification. These yeasts were identified as part of the Mrakia genus. Sugar and alcohol tolerance tests showed that some of these Antarctic soil yeasts were able to grow up to 9% alcohol, and 25% sugar was reached; however, they exhibited longer latency periods compared to the control Saccharomyces cerevisiae. The optimal growing temperature for the isolated Antarctic yeasts was between 10 °C and 15 °C. A comprehensive analysis of the results obtained showed that the isolates 10M3-1, 4M3-6, and 4B1-35 could be good candidates for fermentation purposes due to their alcohol, sugar tolerance, and growth features. Our results prove that it is possible to isolate fermentative yeasts from Antarctic soil with promising characteristics for their potential use in the wine production industry.

El Programa de Iniciación Científica “Mis primeros pasos en la ciencia” cumple once años, lo que demuestra el compromiso de la Universidad Autónoma de Chile por una formación integral de sus estudiantes de pregrado, transformando nuestro entorno académico, fortaleciendo la mirada reflexiva y la capacidad crítica, indispensables para comprender y actuar en el tiempo que vivimos. Este programa, que este 2025 contó con 50 nuevos participantes, no solo abre una puerta hacia la ciencia, sino también hacia el mundo real, donde los conocimientos del aula dialogan con los desafíos contemporáneos. A lo largo de estos años, los estudiantes han impulsado proyectos en ámbitos tan diversos como la transición energética, la inteligencia artificial o la salud pública, demostrando que la ciencia cobra sentido cuando se pone al servicio de la sociedad. Investigar es mucho más que aplicar un método: es una manera de mirar el mundo, de hacerse preguntas y atreverse a buscar respuestas. Esa actitud —curiosa, rigurosa y crítica— es la que el Programa de Iniciación Científica ha cultivado, inspirando a cientos de estudiantes a descubrir el valor del conocimiento como una herramienta de transformación social. Desde la Vicerrectoría de Investigación y Doctorados seguiremos con la convicción de potenciar este valioso espacio de aprendizaje y descubrimiento. Creemos que la formación científica no solo es una oportunidad para desarrollar pensamiento crítico, sensibilidad social y creatividad, sino que una poderosa herramienta para desempeñarse mejor en el campo laboral. Por eso, el Programa de Iniciación Científica no es solo el comienzo de una trayectoria académica, sino un pilar en la construcción de profesionales destacados.