Optical properties of dissolved organic matter relate to different dept-specific patterns of archaeal and bacterial community structure in the North Atlantic Ocean

ArticleProkaryotic abundance, activity and community composition were studied in the euphotic, intermediate and deep waters off the Galician coast (NW Iberian margin) in relation to the optical characterization of dissolved organic matter (DOM). Microbial (archaeal and bacterial) community structure was vertically stratified. Among the Archaea, Euryarchaeota, especially Thermoplasmata, was dominant in the intermediate waters and decreased with depth, whereas marine Thaumarchaeota, especially Marine Group I, was the most abundant archaeal phylum in the deeper layers. The bacterial community was dominated by Proteobacteria through the whole water column. However, Cyanobacteria and Bacteroidetes ocurrence was considerable in the upper layer and SAR202 was dominant in deep waters. Microbial composition and abundande were not shaped by the quantity of dissolved organic carbon, but instead they revealed a strong connection with the DOM quality. Archaeal communities were mainly related to the fluorescence of DOM (which indicates respiration of labile DOM and generation of refractory subproducts), while bacterial communities were mainly linked to the aromaticity/age of the DOM produced along the water column. Taken together, our results indicate that the microbial community composition is associated with the DOM composition of the water masses, suggesting that distinct microbial taxa have the potential to use and/or produce specific DOM compounds.Versión del edito

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Novelty and spatio–temporal heterogeneity in the bacterial diversity of hypersaline Lake Tebenquiche (Salar de Atacama)

14 pages, 7 figures, 3 tablesLake Tebenquiche is one of the largest saline water bodies in the Salar de Atacama at 2,500 m above sea level in northeastern Chile. Bacteria inhabiting there have to deal with extreme changes in salinity, temperature and UV dose (i.e., high environmental dissimilarity in the physical landscape). We analyzed the bacterioplankton structure of this lake by 16S rRNA gene analyses along a spatio–temporal survey. The bacterial assemblage within the lake was quite heterogeneous both in space and time. Salinity changed both in space and time ranging between 1 and 30% (w/v), and total abundances of planktonic prokaryotes in the different sampling points within the lake ranged between two and nine times 106 cells mL−1. Community composition changed accordingly to the particular salinity of each point as depicted by genetic fingerprinting analyses (denaturing gradient gel electrophoresis), showing a high level of variation in species composition from place to place (beta-diversity). Three selected sites were analyzed in more detail by clone libraries. We observed a predominance of Bacteroidetes (about one third of the clones) and Gammaproteobacteria (another third) with respect to all the other bacterial groups. The diversity of Bacteroidetes sequences was large and showed a remarkable degree of novelty. Bacteroidetes formed at least four clusters with no cultured relatives in databases and rather distantly related to any known 16S rRNA sequence. Within this phylum, a rich and diverse presence of Salinibacter relatives was found in the saltiest part of the lake. Lake Tebenquiche included several novel microorganisms of environmental importance and appeared as a large unexplored reservoir of unknown bacteriaSampling and measurements carried out in Chile were funded by grants FONDECYT 1030441 and FONDEF D99I1026. Measurements carried out in Barcelona were funded by grant "ATACAMA-2002" (CICYT, BOS2002-10258-E). Grant "BIOARSENICO" from Fundación BBVA funds current workPeer reviewe