Universidad Dr. Andrés Bello

The type VI secretion system (T6SS) is a contact-dependent multiprotein apparatus that contributes to interbacterial competition and pathogenesis in many Gram-negative bacteria. Salmonella harbors five T6SS gene clusters within the pathogenicity islands SPI-6, SPI-19, SPI-20, SPI-21, and SPI-22, differentially distributed among serotypes. Salmonella enterica subspecies arizonae ( S. arizonae ) is most frequently associated with reptiles but, in some circumstances, can cause disease in mammals, including humans. Notably, although it encodes both T6SS SPI-20 and T6SS SPI-21 , no report to date has demonstrated the antibacterial activity of either system. In addition, only two putative effector proteins have been previously predicted, though they have not been experimentally validated. In the present study, we demonstrate that both T6SS SPI-20 and T6SS SPI-21 contribute to interbacterial competition in S. arizonae when grown on McConkey agar plates, suggesting a role for bile in T6SS SPI-20 and T6SS SPI-21 activity. In addition, through bioinformatic analyses, interbacterial competition assays, and heterologous expression, we further characterize the antibacterial activity of a novel antibacterial E/I module (SARI_02625/SARI_02624, encoded in SPI-21) that, in addition to the previously identified evolved VgrG protein SARI_02603 and VgrG2b homolog SARI_02727, contribute to T6SS-dependent antibacterial competition in S. arizonae .

In 2024, Chile experienced an outbreak of invasive group A Streptococcus (iGAS) infections. Although increasing reports of GAS outbreaks have been described worldwide, it remains unclear whether these events are driven by increased virulence of circulating lineages or by lineage replacement. In parallel, the burden of hospitalized noninvasive GAS infections (h-niGAS), which may present with severe disease, remains poorly characterized. This study aimed to compare epidemiological, clinical, antimicrobial resistance, and genomic features of iGAS and h-niGAS infections in Chile over a six-year period. We analyzed 2,307 GAS isolates collected between 2018 and 2024, including 2,249 noninvasive isolates and 58 iGAS isolates. Noninvasive cases were classified as outpatient niGAS or hospitalized niGAS (h-niGAS). Antimicrobial susceptibility testing was performed for all isolates. emm typing was performed on isolates from hospitalized patients (28 iGAS and 94 h-niGAS). Whole-genome sequencing was performed on outbreak-related isolates, followed by virulence gene profiling and phylogenetic analysis. Clinical characteristics were compared between iGAS and non-iGAS cases and across time periods. Among niGAS isolates, 2,119 were obtained from outpatients and 130 from hospitalized patients. h-niGAS isolates showed the highest proportion of clindamycin resistance (42%), whereas iGAS isolates showed the lowest (16%). Notably, clindamycin resistance among iGAS increased from 0% during 2020-2023 to nearly 20% in 2024. The most frequent emm types were emm1, emm12, and emm4. The frequency of emm1 increased from 0% in 2020-2023 to 10% in 2024, while overall emm diversity declined markedly (Simpson's reciprocal index from 17.3 to 6.63). Clinically, iGAS infections were associated with immunosuppression, chronic liver disease, viral coinfection, and trauma. During the 2024 outbreak, iGAS cases did not differ clinically from those reported in 2018-2023; however, h-niGAS cases required more surgical procedures (p = 0.005) and medical evaluations (p = 0.025). Whole-genome sequencing revealed predominance of emm1, including three M1UK strains harboring all 27 defining single-nucleotide polymorphisms. emm1 isolates carried a higher number of virulence-associated genes compared with non-emm1 isolates (p < 0.05). Phylogenetic analysis showed close relatedness to strains from the United Kingdom, Argentina, and the United States. These findings suggest that the Chilean outbreak was driven by the expansion of the emm1 lineage rather than an increase in strain virulence. The identification of M1UK strains and the reduced emm diversity support a model of lineage introduction and clonal expansion. The significant clinical burden observed among h-niGAS cases underscores the importance of including hospitalized noninvasive infections in surveillance efforts. Ongoing integrated clinical and genomic surveillance of both iGAS and h-niGAS is essential to monitor emerging lineages and antimicrobial resistance trends.

Introduction Hackathons have evolved from programming events to multidisciplinary pedagogical tools in educational settings, demanding structured methodological frameworks to maximize their educational impact. However, there is limited systematization regarding the methodological approaches implemented in student contexts. Methods This study conducted a systematic mapping of the literature to identify and categorize methodological frameworks used in student hackathons, analyzing their organizational structures, evaluation metrics, and reported outcomes. The review followed PRISMA guidelines and consulted three databases (Scopus, Web of Science, IEEE Xplore) for the period 2014–2024. Specific inclusion criteria for student hackathons were applied, resulting in 37 primary studies that met the established quality threshold (score ≥ 5/8). Results Five main categories of hackathons were identified: educational/curricular (48.6%), thematic/specialized (32.4%), civic/social (13.5%), and academic research (5.4%). The most frequent methodological frameworks were Design Thinking, agile methodologies, and Challenge-Based Learning. Predominant evaluation metrics included socio-educational impact, number of participants, participant satisfaction, lessons learned, and skills development. Outcomes were classified as tangible (mainly prototypes, projects, MVPs, and products) and intangible (soft skills development, business ideas, and entrepreneurial skills). Discussion and conclusions Student hackathons exhibit methodological diversity, with no consensus on standardized frameworks. Hybrid methodological approaches appear more effective in achieving educational objectives. Further research is needed to address project sustainability and long-term impact evaluation.

Abstract Active DNA demethylation depends on Ten-Eleven-Translocation (TET) enzymes, which oxidize 5-methylcytosine (mC) to 5-hydroxymethylcytosine (hmC) and further derivatives. Mutations in TET3 , encoding the predominant neuronal isoform, lead to Beck-Fahrner syndrome, a neurodevelopmental disorder. Using human iPSC-derived neurons, we show that TET3 is dispensable for neuronal specification but critical for subsequent maturation. Differentiating TET3 -deficient neurons exhibit delayed transcriptional and proteomic transitions, altered synaptic signatures, and impaired network activity, indicating delayed functional maturation. Mechanistically, we identified an interaction between TET3 and the mC/hmC-binding protein MECP2, pathogenic variants of which cause Rett syndrome. MECP2 negatively regulates TET3 activity, as demonstrated in functional assays and by inverse hmC patterns in MECP2 - and TET3 -deficient neurons. Despite this, MECP2 - and TET3 -deficient neurons exhibit highly similar phenotypes later in differentiation. Our findings uncover a functional interplay between TET3 and MECP2 that coordinates DNA methylation and chromatin dynamics during neuronal maturation, suggesting a shared pathogenic mechanism in Beck-Fahrner and Rett syndromes.

Este ensayo de Contabilidad de Gestión reconoce las etapas del proceso presupuestario aplicable a todo tipo de empresas. Se postula que se inicia con la formulación o actualización de la estrategia empresarial y que se alimenta con un pronóstico de ventas, para compatibilizar lo que se desea impulsar con lo que es viable de alcanzar. Sigue la formulación del presupuesto, que termina con la confección del presupuesto maestro, que debe tener muy presente las metas establecidas en la estrategia empresarial. De esa manera se concluye que el presupuesto maestro permite bajar la estrategia al nivel táctico. En el presupuesto maestro se establecen metas de cumplimiento a todas las divisiones o unidades de negocio que se desee. Posteriormente, mediante control presupuestario, se deberá explicar variaciones. Para esto último, se debe distinguir las que son ocasionadas por variables no controlables (cambios en inflación y en demanda), de las originadas en acciones propias de la empresa. También se postula que debe seguirse una lógica de pronóstico continuo, para identificar variaciones por inflación y demanda. Incluso, puede enfrentarse una situación en que las variaciones presupuestarias y en los pronósticos sean de una magnitud tal que convenga adoptar una práctica de presupuestos continuos.

La violencia es un fenómeno que se encuentra inserta en todas las relaciones humanas, incluyendo vínculos como la familia, la pareja, o amistad, que de acuerdo al imaginario colectivo, deberían ser una red de protección y soporte a lo largo de la vida, sin embargo, los datos obtenido revelan otra realidad, especialmente para la población femenina y aún más en eventos inesperados como la pandemia por COVID-19; es por ello que esta investigación tuvo como objetivo conocer la percepción de la seguridad del hogar asociada a las relaciones filiales y de afinidad de las estudiantes universitarias. El abordaje fue cuantitativo con un alcance descriptivo, y, una muestra de 1,241 encuestas aplicadas a mujeres universitarias, con un rango de edad comprendido entre 17 y 56 años. Los resultados confirman que el hogar, como ámbito privado, es uno de los lugares que las estudiantes perciben como más inseguro y donde se ejerce la violencia con mayor frecuencia, donde el principal reproductor es el hombre, generalmente la pareja, el padre o los tíos; los principales tipos de violencia percibidos son la psicológica, la física y la sexual. En el ámbito público, identifican la calle como el lugar más inseguro, siendo hombres desconocidos los principales reproductores de la violencia. Es por lo anterior que se vuelve clave educar, sensibilizar y concientizar desde edades tempranas a la población en general, con la finalidad de prevenir y con ello minimizar exponencialmente la violencia dirigida a las mujeres en el ciclo vital.

Although levodopa remains the gold standard treatment for Parkinson's disease (PD), its chronic use is associated with levodopa-induced dyskinesia (LID), a motor complication that impacts prognosis, quality of life, and treatment costs. Most known LID-associated factors have been identified in European-descendant populations. To describe the epidemiology of LID in Latin American and Caribbean (LATAM) countries and assess the relevance of known and novel LID-associated factors in this population. We conducted a cross-sectional study using data from the Latin American Research consortium on the Genetics of Parkinson's Disease (LARGE-PD). We included PD patients with information on LID status and levodopa use from eight LATAM countries. LID prevalence was calculated overall and by country. Countries were compared on demographic and clinical variables. Logistic regression was used to identify associations with LID. A total of 3,695 PD patients (58.8% male) were included. Overall LID prevalence was 25.4% [95% CI: 24.06-26.87], ranging from 9.3% in Colombia to 45.1% in Puerto Rico. Prevalence increased progressively with longer disease duration. Country comparisons showed that not all known LID-associated factors explained prevalence differences. In logistic regression, fast disease progression was significantly associated with LID (OR: 1.55, 95%CI: 1.16-2.07), while sex was not (OR: 1.02, 95%CI: 0.87-1.18). This is the largest study on LID epidemiology in LATAM. While some known risk factors remain relevant, others, like sex, do not, underscoring the need for population-specific studies. Future work should integrate environmental, clinical, and genetic data to better understand LID mechanisms.

Las investigaciones de cátedra que se ejecutan en las universidades siguen siendo solo un contenido en una asignatura, por lo que es relevante hablar sobre este tema que sigue acarreando consigo mitos y pensamientos erróneos, por lo que surge la idea de hacer un análisis crítico y proponer recomendaciones prácticas para mejorar la idea que aún se tiene sobre la investigación de cátedra. Se plantea un análisis con enfoque pragmático de la vinculación de la investigación y la práctica profesional, tomando en cuenta una población de estudiantes que ya han realizado investigaciones, mediante una encuesta descriptiva se indaga sobre los mitos que giran en torno a la investigación y los datos que se obtuvieron son el reflejo de factores como la poca motivación para investigar, la dinámica de grupos y la vinculación con el mundo laboral. Finalmente se da un abordaje sobre llevar de la teoría a la práctica cotidiana el proceso de investigación realizado en pregrado y los beneficios que se generan a los investigadores y a la sociedad en general. ABSTRACTThe academic research carried out in universities continues to be only content in a subject, so it is relevant to talk about this topic that continues to carry with it myths and erroneous thoughts, which is why the idea of making a critical analysis and propose practical recommendations to improve the idea that we still have about academic research. An analysis is proposed with a pragmatic approach to the link between research and professional practice, taking into account a population of students who have already carried out research. Through a descriptive survey, the myths that revolve around research and the results obtained reflect factors such as low motivation to research, group dynamics and the connection with the working world. Finally, an approach is given to taking the research process carried out in undergraduate studies from theory to daily practice and the benefits that are generated for researchers and society in general.