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.

Antimicrobial resistance, pathogenic potential, and genomic features of carbapenem-resistant Klebsiella pneumoniae isolated in Chile: high-risk ST25 clones and novel mobile elements.

Multidrug- and carbapenem-resistant Klebsiella pneumoniae (CR-Kp) are critical threats to global health and key traffickers of resistance genes to other pathogens. Despite the sustained increase in CR-Kp infections in Chile, few strains have been described at the genomic level, lacking details of their resistance and virulence determinants and the mobile elements mediating their dissemination. In this work, we studied the antimicrobial susceptibility and performed a comparative genomic analysis of 10 CR-Kp isolates from the Chilean surveillance of carbapenem-resistant Enterobacteriaceae. High resistance was observed among the isolates (five ST25, three ST11, one ST45, and one ST505), which harbored 44 plasmids, most carrying genes for conjugation and resistance to several antibiotics and biocides. Ten plasmids encoding carbapenemases were characterized, including novel plasmids or variants with additional resistance genes, a novel genetic environment for blaKPC-2, and plasmids widely disseminated in South America. ST25 K2 isolates belonging to CG10224, a clone traced back to 2012 in Chile, which recently acquired blaNDM-1, blaNDM-7, or blaKPC-2 plasmids stood out as high-risk clones. Moreover, this corresponds to the first report of ST25 and ST45 Kp producing NDM-7 in South America and ST505 CR-Kp producing both NDM-7 and KPC-2 worldwide. Also, we characterized a variety of genomic islands carrying virulence and fitness factors. These results provide baseline knowledge for a detailed understanding of molecular and genetic determinants behind antibiotic resistance and virulence of CR-Kp in Chile and South America. IMPORTANCE In the ongoing antimicrobial resistance crisis, carbapenem-resistant strains of Klebsiella pneumoniae are critical threats to public health. Besides globally disseminated clones, the burden of local problem clones remains substantial. Although genomic analysis is a powerful tool for improving pathogen and antimicrobial resistance surveillance, it is still restricted in low- to middle-income countries, including Chile, causing them to be underrepresented in genomic databases and epidemiology surveys. This study provided the first 10 complete genomes of the Chilean surveillance for carbapenem-resistant K. pneumoniae in healthcare settings, unveiling their resistance and virulence determinants and the mobile genetic elements mediating their dissemination, placed in the South American and global K. pneumoniae epidemiological context. We found ST25 with K2 capsule as an emerging high-risk clone, along with other lineages producing two carbapenemases and several other resistance and virulence genes encoded in novel plasmids and genomic islands.

Optical transmission properties of Pentelic and Paros marble.

Ancient Greek and Roman sources report that the statue of Zeus in Olympia had a head, and in particular eyes, similar to the description of Zeus by Homer, so we think that the statue was visible to the human eye. Since the temple was 12 m high, and had a small door and no windows, the illumination of the statue by conventional media is questionable. The aim of this paper is to characterize the optical transmission of Paros and Pentelic marble to demonstrate that it was possible to have the Zeus temple illuminated through the roof marble tiles. Spectral absolute transmittance measurements were taken in samples with different thicknesses using a calibrated spectrophotometer, as well as total transmittance measurements using a luxmeter. The results show that both types of marble transmit light and that Pentelic marble has a higher transmittance in the visible range than Paros marble in some cases and hence could have been one reason, among others, to change the type of marble in the roof in antiquity.

ABC de la cirugia laparascópica / ABC of the surgery laparascopica

Manual que guia al cirujano en los principios básicos en los desarollo de la cirugia laparascópica, enseña trucos que hacen su desarollo más facil y seguro, sus capitulos contienen todo lo que hay que saber de la práctica de la cirugia laparascópica

ABC de la cirugia laparascópica / ABC of the surgery laparascopica

Manual que guia al cirujano en los principios básicos en los desarollo de la cirugia laparascópica, enseña trucos que hacen su desarollo más facil y seguro, sus capitulos contienen todo lo que hay que saber de la práctica de la cirugia laparascópica