Properties of genes encoding transfer RNAs as integration sites for genomic islands and prophages in <i>Klebsiella pneumoniae</i>

ABSTRACTThe evolution of traits including antibiotic resistance, virulence, and increased fitness in Klebsiella pneumoniae and related species has been linked to the acquisition of mobile genetic elements through horizontal transfer. Among them, genomic islands (GIs) preferentially integrating at genes encoding tRNAs and the tmRNA (t(m)DNAs) would be significant in promoting chromosomal diversity. Here, we studied the whole set of t(m)DNAs present in 66 Klebsiella chromosomes, investigating their usage as integration sites and the properties of the integrated GIs. A total of 5,624 t(m)DNAs were classified based on their sequence conservation, genomic context, and prevalence. 161 different GIs and prophages were found at these sites, hosting 3,540 gene families including various related to virulence and drug resistance. Phylogenetic analyses supported the acquisition of several of these elements through horizontal gene transfer, likely mediated by a highly diverse set of encoded integrases targeting specific t(m)DNAs and sublocations inside them. Only a subset of the t(m)DNAs had integrated GIs and even identical tDNA copies showed dissimilar usage frequencies, suggesting that the genomic context would influence the integration site selection. This usage bias, likely towards avoiding disruption of polycistronic transcriptional units, would be conserved across Gammaproteobacteria. The systematic comparison of the t(m)DNAs across different strains allowed us to discover an unprecedented number of K. pneumoniae GIs and prophages and to raise important questions and clues regarding the fundamental properties of t(m)DNAs as targets for the integration of mobile genetic elements and drivers of bacterial genome evolution and pathogen emergence.</jats:p

Estudio y análisis del sistema eléctrico ecuatoriano mediante el modelo PLP

Ingeniero Civil EléctricoLas interconexiones interncionales el día de hoy son un tema de importancia, ya que tienen grandes beneficios tanto para sistemas pequeños, como grandes, al ayudar a mejorar los precios del país, además de reforzar el sistema mientras mayor se la interconexión. Con esto en mente, este trabajo da inicio al estudio de una posible interconexión de los países sudamericanos, en particular, los presentes en el el mar del pácifico, Chile, Perú, Ecuador y Colombia. De esta forma, este trabajo presenta los resutados obtenidos del sistema ecuatoriano, para poder realizar futuras investigaciones con respecto a la interconexión de estos países. Los resultados obtenidos corresponden a los costos marginales, la generación, los niveles de embalse y la cargabilidad de las lineas, cada uno de ellos validados según los supuestos tomados al realizar el modelo. Además, también se muestra como se organiza y funciona el sistema eléctrico ecuatoriano. Po último, se compara los costos marginales de Ecuador con Colombia, para poder ver si se tiene un beneficio mutuo para ambos países, al realizar una interconexión entre ellos

Diversity, Taxonomic Novelty, and Encoded Functions of Salar de Ascotán Microbiota, as Revealed by Metagenome-Assembled Genomes

Salar de Ascotán is a high-altitude arsenic-rich salt flat exposed to high ultraviolet radiation in the Atacama Desert, Chile. It hosts unique endemic flora and fauna and is an essential habitat for migratory birds, making it an important site for conservation and protection. However, there is limited information on the resident microbiota’s diversity, genomic features, metabolic potential, and molecular mechanisms that enable it to thrive in this extreme environment. We used long- and short-read metagenomics to investigate the microbial communities in Ascotán’s water, sediment, and soil. Bacteria predominated, mainly Pseudomonadota, Acidobacteriota, and Bacteroidota, with a remarkable diversity of archaea in the soil. Following hybrid assembly, we recovered high-quality bacterial (101) and archaeal (6) metagenome-assembled genomes (MAGs), including representatives of two putative novel families of Patescibacteria and Pseudomonadota and two novel orders from the archaeal classes Halobacteriota and Thermoplasmata. We found different metabolic capabilities across distinct lineages and a widespread presence of genes related to stress response, DNA repair, and resistance to arsenic and other metals. These results highlight the remarkable diversity and taxonomic novelty of the Salar de Ascotán microbiota and its rich functional repertoire, making it able to resist different harsh conditions. The highly complete MAGs described here could serve future studies and bioprospection efforts focused on salt flat extremophiles, and contribute to enriching databases with microbial genome data from underrepresented regions of our planet