Universidad de Magallanes
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Indigenous and local knowledge on social-ecological changes is positively associated with livelihood resilience in a Globally Important Agricultural Heritage System
No full textCONTEXT: Rapid social -ecological changes such as climate change, biodiversity loss, and resource overexploitation are threatening food security, livelihoods, and local knowledge of small-scale farmers worldwide. There has been a call from scientists, farmers, and activists to identify and promote the mechanisms for sustaining resilient farming livelihoods. We hypothesize that small-scale farmers who are more knowledgeable about changes in their environment are more resilient to current social -ecological changes as they might be more prepared to respond to these disturbances. OBJECTIVE: Our objective is to understand how Indigenous and local knowledge on social -ecological changes is associated with small-scale farmers' livelihood resilience in the Chiloe ' Archipelago, a Globally Important Agricultural Heritage System and Global Biodiversity Hotspot in southern South America. METHODS: We conducted 100 surveys with small-scale farmers whose main livelihood activity relied on agrosilvopastoral systems. By asking questions about noticed changes in the atmospheric, physical, biological, and human system, we built an Index of Knowledge on Social -Ecological Changes. We also built an Index of Livelihood Resilience based on households' information on indicators of five capital assets (i.e., financial, human, social, physical, and natural). Finally, by using general linear mixed models, we tested the association between the Index of Knowledge on Social -Ecological Changes, individual capital assets, and the Index of Livelihood Resilience. RESULTS AND CONCLUSIONS: We found that the level of small-scale farmers' knowledge was similar across the different systems (atmospheric, physical, biological, and human). We observed a significant positive association between the Index of Knowledge on Social -Ecological Changes and the Index of Livelihood Resilience, as well as with the natural, social, and physical capital of small-scale farmers. SIGNIFICANCE: By demonstrating the positive association between measures of Indigenous and local knowledge on social -ecological changes and indicators of livelihood resilience, our results suggest that people who are more knowledgeable about changes in their environment might be more prepared to respond to disturbances. While there might be other factors influencing livelihood resilience, our study highlights the importance of leveraging Indigenous and local knowledge, and their respective holders, when planning responses to current socialecological crises
Temperature Dependence and the Effects of Ultraviolet Radiation on the Ultrastructure and Photosynthetic Activity of Carpospores in Sub-Antarctic Red Alga Iridaea cordata (Turner) Bory 1826
No full textThe short-term effects of UV radiation and low temperature on ultrastructure, photosynthetic activity (measured as the maximal photochemical quantum yield of photosystem II: F-v/F-m), chlorophyll-a (Chl-a) contents, and UV-absorbing compounds on the carpospores of Iridaea cordata from a sub-Antarctic population were investigated. Exposure to both photosynthetically active radiation (PAR) and PAR + UV for 4 h caused ultrastructural modifications in all treatments. Under PAR + UV at 2 degrees C, a disruption of the chloroplast's internal organization was observed. Plastoglobuli were often found in carpospores exposed to 2 degrees C. 'Electron dense particles', resembling physodes of brown algae, were detected for the first time in cells exposed to PAR and PAR + UV at 8 degrees C. F-v/F-m decreased following 4 h exposure at 2 degrees C under PAR + UV (64%) and PAR (25%). At 8 degrees C, F-v/F-m declined by 21% only under PAR + UV. The photosynthesis of carpospores previously treated with UV partially recovered after a 4 h exposure under dim light. UV-absorbing compounds were degraded in all radiation and temperature treatments without recovery after a 4 h dim light period. Chl-a did not change, whereas total carotenoids increased under PAR at 8 degrees C The study indicates that although carpospores of I. cordata exhibit photoprotective mechanisms, UV radiation strongly damages their ultrastructure and physiology, which were exacerbated under low temperatures
Ecological filtering and phylogeographic structuring of Psychrilyobacter within two closely related limpet species from the Southern Ocean
No full textPurpose The ecological interdependence between macroorganisms and their microbial communities promotes stable associations over time, potentially leading to their evolutionary co-diversification. The detection of intricate eco-evolutionary interactions between animals and their microbiota is challenging, primarily due to complex bacterial communities related to poorly resolved host population structure. Strikingly, co-diversification in invertebrates, characterized by generally less complex microbiota, remains largely unexplored. Here, we compared the bacterial communities associated with two distinct lineages of Nacella limpets, a dominant shallow water patellogastropod of the Southern Ocean shores with a well-described population structure. Our goals were to elucidate the uniqueness of Nacella microbiota, resulting from an ecological filter that selectively favors certain bacterial taxa. Additionally, we aimed to depict the genetic structure of bacterial symbiont seeking evidence of co-diversification with Nacella. Methods We sequence the V4-V5 regions of the bacterial 16S rRNA gene in three distinct microenvironments associated with Nacella: rock substrate, radula, and whole intestine. These samples were collected from two populations of Nacella deaurata and Nacella concinna, located in the West Antarctic Peninsula and Falkland/Malvinas Islands, respectively. Results We assessed ecological filtering patterns in the limpet microbiota, uncovering unique bacterial communities in both radulas and intestines, with specifically enriched bacterial taxa compared to the surrounding environment. By examining microdiversity patterns of core bacterial taxa, we revealed a deep phylogeographic structure of Psychrilyobacter in Nacella intestines. Conclusion We highlight the Southern Ocean limpets of the Nacella genus as a novel and promising model for studying co-diversification between marine mollusks and their resident microbiota
Mortality Due to Acute Respiratory Distress Syndrome in Latin America
No full textOBJECTIVES: Mortality due to acute respiratory distress syndrome (ARDS) is a major global health problem. Knowledge of epidemiological data on ARDS is crucial to design management, treatment strategies, and optimize resources. There is ample data regarding mortality of ARDS from high-income countries; in this review, we evaluated mortality due to ARDS in Latin America. DATA SOURCES: We searched in PubMed, Cochrane Central Register of Controlled Trials, Web of Science, and Latin American and Caribbean Health Science Literature databases from 1967 to March 2023. STUDY SELECTION: We searched prospective or retrospective observational studies and randomized controlled trials conducted in Latin American countries reporting ARDS mortality. DATA EXTRACTION: Three pairs of independent reviewers checked all studies for eligibility based on their titles and abstracts. We performed meta-analysis of proportions using a random-effects model. We performed sensitivity analyses including studies with low risk of bias and with diagnosis using the Berlin definition. Subgroup analysis comparing different study designs, time of publication (up to 2000 and from 2001 to present), and studies in which the diagnosis of ARDS was made using Pao(2)/Fio(2) less than or equal to 200 and regional variations. Subsequently, we performed meta-regression analyses. Finally, we graded the certainty of the evidence (Grading of Recommendations Assessment, Development, and Evaluation). DATA SYNTHESIS: Of 3315 articles identified, 32 were included (3627 patients). Mortality was 52% in the pooled group (low certainty of evidence). In the sensitivity analysis (according to the Berlin definition), mortality was 46% (moderate certainty of evidence). In the subgroup analysis mortality was 53% (randomized controlled trials), 51% (observational studies), 66% (studies published up to 2000), 50% (studies after 2000), 44% (studies with Pao(2)/Fio(2) <= 200), 56% (studies from Argentina/Brazil), and 40% (others countries). No variables were associated with mortality in the meta-regression. CONCLUSIONS: ARDS mortality in Latin America remains high, as in other regions. These results should constitute the basis for action planning to improve the prognosis of patients with ARDS (PROSPERO [CRD42022354035])
An overview of the hypolipidemic effect of Genus Berberis
No full textDyslipidemia is a chronic disease characterized by elevated blood lipid levels treatable with statins. However, long-term statin use may have adverse effects, such as liver damage and memory loss. Nevertheless, plants and their active compounds effectively and safely improve lipid profiles. This review aims to update information on the genus Berberis as a hypolipidemic agent, assess the effects of these extracts on organisms and provide evidence supporting the use of these natural products in pharmaceutical drugs. Berberis species with therapeutic potential include B. vulgaris, B. integerrima, B. aristata, B. lycium, B. orthobotrys, and B. calliobotrys, which have shown promising results in reducing lipid levels in humans and other animals. In addition, combining berberine with nutraceuticals may improve its intestinal absorption, enhancing its lipid-lowering effect. Herbal medicine studies suggest that Berberis has a high potential for the management of hyperlipidemia
Paleoceanography of the Southeast Pacific since the late glacial from diatom and foraminiferal assemblages
No full textThe Southern Ocean is a key region for climate changes, notably for deep ocean-atmosphere CO2 exchange, linked to the upwelling of deep waters, south to the Polar Front, that is driven through Southern Hemisphere Westerly Winds and Antarctic Circumpolar Current positions and intensities. Previous studies using a range of different proxies have proposed the latitudinal migration of the Antarctic Circumpolar Current and Southern Westerly Winds in the Southeast Pacific since the Last Glacial Maximum, but with conflicting results. We present a paleoceanographic reconstruction from the Last Glacial period to the Late Holocene based on diatom and foraminiferal assemblages from the marine sediment core MD07-3081, retrieved from the Southeast Pacific at 49 degrees S, proximal (similar to 100 km) offshore the south coast of Chile. During the Last Glacial, the presence of polar diatoms is not observed, suggesting that the Polar Front did not approach 49 degrees S. During the deglaciation, an increase of Chaetoceros spp. spores is observed together with the opportunistic planktonic foraminifer Globigerinita glutinata, which indicates a greater nutrient availability, linked to the influence of the Southern Ocean upwelling. The presence of Neogloboquadrina incompta, a subtropical species, during two periods of the deglaciation (15.2 ka and 12.3-11.5 ka) is associated with a southward shift of the Subtropical Front linked to a reduction of the South Pacific split jet. During the deglaciation to the Early Holocene transition, the increase of open ocean diatoms thriving both north and south of the Subantarctic Zone indicates a greater influence of the Antarctic Circumpolar Current, possibly displaced similar to 3 degrees south of its current position at 46 degrees S. In the Late Holocene, the increase of subtropical-temperate species, e.g. Fragilariopsis doliolus, is indicative of a greater influence of warm waters coming from the Peru-Chile Countercurrent. This study of the diatom and foraminiferal assemblages provide new insights into the paleoceanography of the SE Pacific since the Last Glacial Maximum and the role of the Southern Ocean during this climate transition
Hongos y Líquenes en Atacama: estrategias de sobrevivencia en un ambiente extremo
No full textEI desierto de Atacama tiene condiciones extremas de aridez y temperatura a las que pocos organismos son capaces de sobrevivir. ¿Cómo pueden obtener el agua y los nutrientes necesarios para vivir y reproducirse? En este capítulo revisaremos la riqueza de especies de macrohongos y líquenes presentes en la región de Atacama y su diversidad, así como las variadas estrategias que los representantes del Reino Fungi han desarrollado para habitar la diversidad de sustratos y de condiciones ambientales que ofrece este desierto extraordinario
Population structure of free-ranging introduced monk parakeets (Myiopsitta monachus) in Santiago, Chile
No full textThe monk parakeet (Myiopsitta monachus) is an invasive species introduced in Chile during the early seventies and now abundant in several areas of Santiago metropolis. For most of our knowledge, there are no genetic studies focused on the invasion of monk parakeets in Chile. The current study aims to assess the levels of population structure in monk parakeets from different municipalities in Santiago through next generation sequencing. Genetic material was obtained from pectoral muscle collected from monk parakeet fledglings (n = 204) sampled in Santiago, Chile. Using Double digest, restriction-site associated DNA (ddRADseq), 102,834 loci and 3195 SNPs were identified, allowing a high-resolution study in a population with little genetic diversity explained by an invasive founder effect. Genetic structure was modeled using the fixation index, STRUCTURE, and principal component analyses. Results showed low levels of genetic structure in the monk parakeet population from Santiago, evidencing high genetic flow between all studied municipalities. However, slight differences were observed when parakeets from the northern areas of Santiago were compared to those from the rest of the city. The geography of the city might explain these differences; with a small succession of hills of up to 400 m, potentially in-part isolating a northern reproductive colony. It is also possible that this northern population originated from or bred with a different release event or a combination of these factors. This study represents the first genetic characterization of monk parakeets in Chile and provides a high-resolution model to study recent invasion processes
The first gravid ichthyosaur from the Hauterivian (Early Cretaceous): a complete Myobradypterygius hauthali von Huene, 1927 excavated from the border of the Tyndall Glacier, Torres del Paine National Park, southernmost Chile
No full textIchthyosaurs were pelagic marine reptiles with a global distribution through most of the Mesozoic. Cretaceous Ichthyosauria are mostly known from the northern hemisphere, although findings from the southern hemisphere have been reported from Australia, Argentina, Chile, and New Zealand. Despite these findings that have contributed to knowledge of the clade, there is still a dearth of information about the evolution, phylogenetics, and ecology of Cretaceous ichthyosaurs from the Southernmost Pacific margin of Gondwana. A Lower Cretaceous locality next to the Tyndall Glacier, inside Torres del Paine National Park, southernmost Chile, has yielded 87 ichthyosaur skeletons to date. Most of the specimens recorded from this area are complete and articulated, however, they are affected by recent weathering and the constant erosion. Here we describe a complete platypterygiine ichthyosaur, which we provisionally assign to Myobradypterygius hauthali von Huene, 1927. The specimen was excavated from the border of the glacier in Patagonia during March and April 2022 and corresponds to the first complete excavated ichthyosaur from Chile. This specimen additionally preserves gastrointestinal contents and is the only Hauterivian (131 Ma) ichthyosaur documented to date containing the articulated skeleton of a preserved fetus. This research increases the knowledge of the paleobiology of the species. In addition to morphology, it contributes information regarding paleoecology and paleopathology, diet, and reproduction in M. hauthali, a taxon potentially restricted to the Pacific margin of Gondwana
Autonomous B-cell receptor signaling and genetic aberrations in chronic lymphocytic leukemia-phenotype monoclonal B lymphocytosis in siblings of patients with chronic lymphocytic leukemia
No full textClonal expansion of CD5-expressing B cells, commonly designated as monoclonal B lymphocytosis (MBL), is a precursor condition for chronic lymphocytic leukemia (CLL). The mechanisms driving subclinical MBL B-cell expansion and progression to CLL, occurring in approximately 1% of affected individuals, are unknown. An autonomously signaling B-cell receptor (BCR) is essential for the pathogenesis of CLL. The objectives of this study were functional characterization of the BCR of MBL in siblings of CLL patients and a comparison of genetic variants in MBL-CLL sibling pairs. Screening of peripheral blood by flow cytometry detected 0.2-480 clonal CLL-phenotype cells per microliter (median: 37/mu L) in 34 of 191 (17.8%) siblings of CLL patients. Clonal BCR isolated from highly purified CLL-phenotype cells induced robust calcium mobilization in BCR-deficient murine pre -B cells in the absence of external antigen and without experimental crosslinking. This autonomous BCR signal was less intense than the signal originating from the CLL BCR of their CLL siblings. According to genotyping by single nucleotide polymorphism array, whole exome, and targeted panel sequencing, CLL risk alleles were found with high and similar prevalence in CLL patients and MBL siblings, respectively. Likewise, the prevalence of recurrent CLL-associated genetic variants was similar between CLL and matched MBL samples. However, copy number variations and small variants were frequently subclonal in MBL cells, suggesting their acquisition during subclinical clonal expansion. These findings support a stepwise model of CLL pathogenesis, in which autonomous BCR signaling leads to a non-malignant (oligo)clonal expansion of CD5+ B cells, followed by malignant progression to CLL after acquisition of pathogenic genetic variants