Universidad del Desarrollo

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Emission of polycyclic aromatic hydrocarbons in the north-west Antarctic Peninsula region
(2024)
María J. Valdivia
;
Sebastián Sánchez
;
Jennifer Saa
;
Roberto Bastías
;
Gastón Higuera
Scopus© Citations 1 8
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Mutation in a SARS-CoV-2 Haplotype from Sub-Antarctic Chile Reveals New Insights into the Spike’s Dynamics
(2021)
Jorge González-Puelma
;
Jacqueline Aldridge
;
Marco Montes de Oca
;
Mónica Pinto
;
Roberto Uribe-Paredes
<jats:p>The emergence of SARS-CoV-2 variants, as observed with the D614G spike protein mutant and, more recently, with B.1.1.7 (501Y.V1), B.1.351 (501Y.V2) and B.1.1.28.1 (P.1) lineages, represent a continuous threat and might lead to strains of higher infectivity and/or virulence. We report on the occurrence of a SARS-CoV-2 haplotype with nine mutations including D614G/T307I double-mutation of the spike. This variant expanded and completely replaced previous lineages within a short period in the subantarctic Magallanes Region, southern Chile. The rapid lineage shift was accompanied by a significant increase of cases, resulting in one of the highest incidence rates worldwide. Comparative coarse-grained molecular dynamic simulations indicated that T307I and D614G belong to a previously unrecognized dynamic domain, interfering with the mobility of the receptor binding domain of the spike. The T307I mutation showed a synergistic effect with the D614G. Continuous surveillance of new mutations and molecular analyses of such variations are important tools to understand the molecular mechanisms defining infectivity and virulence of current and future SARS-CoV-2 strains.</jats:p>
1Scopus© Citations 9
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Stable water isotopes and accumulation rates in the Union Glacier region, Ellsworth Mountains, West Antarctica, over the last 35 years
(2020)
Kirstin Hoffmann
;
Francisco Fernandoy
;
Hanno Meyer
;
Elizabeth R. Thomas
;
Marcelo Aliaga
<jats:p>Abstract. Antarctica is well known to be highly susceptible to atmospheric and oceanic warming. However, due to the lack of long-term and in situ meteorological observations, little is known about the magnitude of the warming and the meteorological conditions in the intersection region between the Antarctic Peninsula (AP), the West Antarctic Ice Sheet (WAIS) and the East Antarctic Ice Sheet (EAIS). Here we present new stable water isotope data (δ18O, δD, d excess) and accumulation rates from firn cores in the Union Glacier (UG) region, located in the Ellsworth Mountains at the northern edge of the WAIS. The firn core stable oxygen isotopes and the d excess exhibit no statistically significant trend for the period 1980–2014, suggesting that regional changes in near-surface air temperature and moisture source variability have been small during the last 35 years. Backward trajectory modelling revealed the Weddell Sea sector, Coats Land and Dronning Maud Land (DML) to be the main moisture source regions for the study site throughout the year. We found that mean annual δ18O (δD) values in the UG region are negatively correlated with sea ice concentrations (SICs) in the northern Weddell Sea but not influenced by large-scale modes of climate variability such as the Southern Annular Mode (SAM) and the El Niño–Southern Oscillation (ENSO). Only mean annual d-excess values show a weak positive correlation with the SAM. On average annual snow accumulation in the UG region amounts to 0.245 m w.e. a−1 in 1980–2014 and has slightly decreased during this period. It is only weakly related to sea ice conditions in the Weddell Sea sector and not correlated with SAM and ENSO. We conclude that neither the rapid warming nor the large increases in snow accumulation observed on the AP and in West Antarctica during the last decades have extended inland to the Ellsworth Mountains. Hence, the UG region, although located at the northern edge of the WAIS and relatively close to the AP, exhibits rather stable climate characteristics similar to those observed in East Antarctica. </jats:p>
1Scopus© Citations 12
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Novel Vector of Scrub Typhus in Sub-Antarctic Chile: Evidence From Human Exposure
(2021)
WEITZEL, THOMAS
;
María Carolina Silva-de la Fuente
;
Constanza Martínez-Valdebenito
;
Alexandr A Stekolnikov
;
Caricia Pérez
<jats:title>Abstract</jats:title> <jats:p>The exposure of a research team to chigger mites in southern Chile allowed the first identification of a trombiculid species as vector and reservoir of scrub typhus outside the tsutsugamushi triangle, providing unique insights into the ecology and transmission of this recently discovered rickettsial infection in South America.</jats:p>
Scopus© Citations 22 5

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