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The Pantanal biome, at the confluence of Brazil, Bolivia and Paraguay, is the largest continental wetland on the planet and an invaluable reserve of biodiversity. The exceptional 2020 fire season in Pantanal drew particular attention due to the severe wildfires and the catastrophic natural and socio-economic impacts witnessed within the biome. So far, little progress has been made in order to better understand the influence of climate extremes on fire occurrence in Pantanal. Here, we evaluate how extreme hot conditions, through heatwave events, are related to the occurrence and the exacerbation of fires in this region. A historical analysis using a statistical regression model found that heatwaves during the dry season explained 82% of the interannual variability of burned area during the fire season. In a future perspective, an ensemble of CORDEX-CORE simulations assuming different Representative Concentration Pathways (RCP2.6 and RCP8.5), reveal a significant increasing trend in heatwave occurrence over Pantanal. Compared to historical levels, the RCP2.6 scenario leads to more than a doubling in the Pantanal heatwave incidence during the dry season by the second half of the 21st century, followed by a plateauing. Alternatively, RCP8.5 projects a steady increase of heatwave incidence until the end of the century, pointing to a very severe scenario in which heatwave conditions would be observed nearly over all the Pantanal area and during practically all the days of the dry season. Accordingly, favorable conditions for fire spread and consequent large burned areas are expected to occur more often in the future, posing a dramatic short-term threat to the ecosystem if no preservation action is undertaken.
Asunto(s)
Ecosistema , Incendios Forestales , Biodiversidad , Clima , Estaciones del AñoRESUMEN
During a survey in a tomato field in Luziânia (Goiás State, Brazil), a single plant with mottling, chlorotic spots, and leaf distortion was found. A new bipartite begomovirus sequence was identified using nanopore sequence technology and confirmed by Sanger sequencing. The highest nucleotide sequence identity match of the DNA-A component (2596 bases) was 81.64% with tomato golden leaf deformation virus (HM357456). Due to the current species demarcation criterion of 91% nucleotide sequence identity for DNA-A, we propose this virus to be a new member of the genus Begomovirus, named "tomato mottle leaf distortion virus".
Asunto(s)
Begomovirus/genética , Secuenciación de Nanoporos/métodos , Filogenia , Enfermedades de las Plantas/virología , Solanum lycopersicum/virología , Begomovirus/aislamiento & purificación , Brasil , Genoma ViralRESUMEN
The Brazilian savanna (Cerrado) is considered the most floristically diverse savanna in the world, home to more than seven thousand species. The region is a mosaic of savannas, grasslands and forests whose unique biophysical and landscape attributes are on the basis of a recent ecoregional map, paving the way to improved region-based strategies for land management actions. However, as a fire-prone ecosystem, Cerrado owes much of its distribution and ecological properties to the fire regime and contributes to an important parcel of South America burned area. Accordingly, any attempt to use ecoregion geography as a guide for management strategies should take fire into account, as an essential variable. The main aim of this study is to complement the ecoregional map of the Cerrado with information related to the fire component. Using remotely sensed information, we identify patterns and trends of fire frequency, intensity, seasonality, extent and scar size, and combine this information for each ecoregion, relying on a simple classification that summarizes the main fire characteristics over the last two decades. Results show a marked north-south fire activity gradient, with increased contributions from MATOPIBA, the latest agricultural frontier. Five ecoregions alone account for two thirds of yearly burned area. More intense fires are found in the Arc of Deforestation and eastern ecoregions, while ecoregions in MATOPIBA display decreasing fire intensity. An innovative analysis of fire scars stratified by size class shows that infrequent large fires are responsible for the majority of burned area. These large fires display positive trends over many ecoregions, whereas smaller fires, albeit more frequent, have been decreasing in number. The final fire classification scheme shows well defined spatially-aggregated groups, where trends are found to be the key factor to evaluate fire within their regional contexts. Results presented here provide new insights to improve fire management strategies under a changing climate.
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Ecosistema , Incendios , Brasil , Bosques , PraderaRESUMEN
The outstanding electronic properties of carbon black (CB) and its economic advantages have fueled its application as nanostructured electrode material for the development of new electrochemical sensors and biosensors. CB-based electrochemical sensing devices have been found to exhibit high surface area, fast charge transfer kinetics, and excellent functionalization. In the present work, we set forth a comprehensive review of the recent advances made in the development and application of CB-based electrochemical devices for pharmaceutical and biomedical analyses - from quantitative monitoring of drug formulations to clinical diagnoses - and the underlying challenges and constraints that need to be overcome. We also present a thorough discussion about the strategies and techniques employed in the development of new electrochemical sensing platforms and in the enhancement of their analytical properties and biocompatibility for anchoring active biomolecules, as well as the combination of these sensing devices with other materials aiming at boosting the performance and efficiency of the sensors.
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Técnicas Biosensibles , Nanoestructuras , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Nanoestructuras/química , Preparaciones Farmacéuticas , HollínRESUMEN
Bacterial and fungal infections are challenging due to their low susceptibility and resistance to antimicrobial drugs. For this reason, antimicrobial peptides (AMP) emerge as excellent alternatives to overcome these problems. At the same time, their active insertion into the cell wall of microorganisms can be availed for biorecognition applications in biosensing platforms. Temporin-PTA (T-PTA) is an AMP found in the skin secretions of the Malaysian fire frog Hylarana picturata, which presents antibacterial activity against MRSA, Escherichia coli, and Bacillus subtilis. In this work, T-PTA was explored as an innovative sensing layer aiming for the electrochemical differentiation of Klebsiella pneumoniae, Acinetobacter baumannii, Bacillus subtilis, Enterococcus faecalis, Candida albicans, and C. tropicalis based on the structural differences of their membranes. The biosensor was analyzed through electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). In this approach, the different structural features of each microorganism resulted in different adherence degrees and, therefore, different electrochemical responses. The transducing layer was fabricated by the self-assembling of a 4-mercaptobenzoic acid (MBA) monolayer and gold-capped magnetic nanoparticles (Fe3O4@Au) implemented to improve the electrical signal of the biointeraction. We found that each interaction, expressed in variations of electron transfer resistance and anodic peak current, demonstrated a singular response from which the platform can discriminate all different microorganisms. We found expressive sensitivity towards Gram-negative species, especially K. pneumoniae. A detection limit of 101 CFU.mL-1 and a linear range of 101 to 105 CFU.mL-1 were obtained. The T-PTA biosensor platform is a promising and effective tool for microbial identification.
Asunto(s)
Técnicas Biosensibles , Péptidos Catiónicos Antimicrobianos/química , Técnicas Biosensibles/métodos , Electrodos , Oro/químicaRESUMEN
Climate change is drastically altering the frequency, duration, and severity of compound drought-heatwave (CDHW) episodes, which present a new challenge in environmental and socioeconomic sectors. These threats are of particular importance in low-income regions with growing populations, fragile infrastructure, and threatened ecosystems. This review synthesizes emerging progress in the understanding of CDHW patterns in Brazil while providing insights about the impacts on fire occurrence and public health. Evidence is mounting that heatwaves are becoming increasingly linked with droughts in northeastern and southeastern Brazil, the Amazonia, and the Pantanal. In those regions, recent studies have begun to build a better understanding of the physical mechanisms behind CDHW events, such as the soil moisture-atmosphere coupling, promoted by exceptional atmospheric blocking conditions. Results hint at a synergy between CDHW events and high fire activity in the country over the last decades, with the most recent example being the catastrophic 2020 fires in the Pantanal. Moreover, we show that HWs were responsible for increasing mortality and preterm births during record-breaking droughts in southeastern Brazil. This work paves the way for a more in-depth understanding on CDHW events and their impacts, which is crucial to enhance the adaptive capacity of different Brazilian sectors.
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Sequías , Ecosistema , Recién Nacido , Humanos , Brasil , Cambio Climático , SueloRESUMEN
AIMS: Quercetin has been investigated as an agent to treat rheumatoid arthritis. At high doses it improves inflammation and the antioxidant status of arthritic rats, but it also exerts mitochondriotoxic and pro-oxidant activities. Beneficial effects of quercetin have not been found at low doses because of its chemical instability and low bioavailability. In the hope of overcoming these problems this study investigated the effects of long-term administration of quercetin-loaded pectin/casein microparticles on the oxidative status of liver and brain of rats with adjuvant-induced arthritis. MAIN METHODS: Particle morphology was viewed with transmission electron microscopy and the encapsulation efficiency was measured indirectly by X-ray diffraction. Quercetin microcapsules (10 mg/Kg) were orally administered to rats during 60 days. Inflammation indicators and oxidative stress markers were measured in addition to the respiratory activity and ROS production in isolated mitochondria. KEY FINDINGS: Quercetin was efficiently encapsulated inside the polymeric matrix, forming a solid amorphous solution. The administration of quercetin microparticles to arthritic rats almost normalized protein carbonylation, lipid peroxidation, the levels of reactive oxygen species as well as the reduced glutathione content in both liver and brain. The paw edema in arthritic rats was not responsive, but the plasmatic activity of ALT and the mitochondrial respiration were not affected by quercetin, indicating absence of mitochondriotoxic or hepatotoxic actions. SIGNIFICANCE: Quercetin-loaded pectin/casein microcapsules orally administered at a low dose improve oxidative stress of arthritic rats without a strong anti-inflammatory activity. This supports the long-term use of quercetin as an antioxidant agent to treat rheumatoid arthritis.
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Artritis Experimental/patología , Caseínas/química , Microesferas , Estrés Oxidativo , Pectinas/química , Quercetina/farmacología , Alanina Transaminasa/sangre , Animales , Antioxidantes/farmacología , Artritis Experimental/sangre , Encéfalo/efectos de los fármacos , Encéfalo/patología , Rastreo Diferencial de Calorimetría , Respiración de la Célula/efectos de los fármacos , Edema/patología , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Mitocondrias Hepáticas/efectos de los fármacos , Mitocondrias Hepáticas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Oxidorreductasas/metabolismo , Ratas , Especies Reactivas de Oxígeno/metabolismo , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos XRESUMEN
Abstract Invasive species are one of the main causes of biodiversity loss and the knowledge of their distribution is essential for conservation efforts. The present study inventoried the land and freshwater invasive molluscs of 25 villages of Ilha Grande (Rio de Janeiro, Brazil), an island with Atlantic Rainforest remnants. Three invasive species are found: Melanoides tuberculata (Müller, 1774), Physa acuta Draparnaud, 1805, both on two localities; and Achatina fulica Bowdich, 1822, on 16 localities. Most records were done on the island continental side, in anthropic areas, probably due to ease of access. One record was inside a conservation area, that calls concern about the spread of those species on the island and possible effects.
Resumo As espécies invasoras são uma das maiores causas de perda de biodiversidade e o conhecimento acerca da sua distribuição é essencial para os esforços de conservação. O presente estudo inventariou os moluscos continentais invasores em 25 vilas da Ilha Grande (Rio de Janeiro, Brasil), uma ilha com remanescentes de Mata Atlântica. Três espécies invasoras foram encontradas: Melanoides tuberculata (Müller, 1774), Physa acuta Draparnaud, 1805, ambas em duas localidades; e Achatina fulica Bowdich, 1822, em 16 localidades. A maior parte dos registros foi no lado continental da ilha, provavelmente devido a facilidade de acesso. Um dos registros foi dentro de uma área de conservação, o que chama a atenção para a dispersão destas espécies na ilha, e seus possíveis efeitos.
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An expanded list of generic level larval characteristics is presented for Chrysopodes; it includes a reinterpretation of the mesothoracic and metathoracic structure and setation. Keys, descriptions and images of Semaphoront A (first instar) and Semaphoront B (second and third instars) are offered for identifying five species of Chrysopodes (Chrysopodes) that are commonly reported from horticultural habitats in the Neotropical region.
ResumoUma lista expandida das características larvais em nível de gênero é apresentada para Chrysopodes, incluindo a reinterpretação da estrutura e das cerdas do mesotórax e metatórax. Chaves, descrições e imagens do semaforonte A (primeiro instar) e semaforonte B (segundo e terceiro instares) são fornecidas para a identificação de cinco espécies de Chrysopodes (Chrysopodes) comumente encontradas em habitats hortícolas na região Neotropical.
RESUMEN
Padröes de deposiçäo de gordura foram investigados em fêmeas e machos de camundongos selecionados de modo divergente para estrutura coroporal. A seleçäo foi feita com um critério agonístico entre peso corporal e comprimento do rabo, em contraste com a seleçäo antagonística anteriormente feita. As linhas foram comparadas dentro dos padröes sexuais de deposiçäo de gordura com a forma logarítmica e a equaçäo alométrica. Entretanto as linhas selecionadas foram significativamente diferentes no peso corporal e nenhuma diferença no conteudo de gordura dos adultos foi encontrada entre eles. Fêmeas de ambas as linhas selecionadas mostraram um padräo de deposiçäo de gordura näo dependente de peso, como encontrado com seleçäo antagonística, enquanto machos mostraram um padräo dependente de peso para ambos os procedimentos de seleçäo. Fêmeas selecionadas näo diferiram em termos de conteudo de gordura no corpo adulto se selecionadas tanto para peso corporal alto ou baixo, entretanto ambas eram mais gordas do que os controles näo selecionados. Estes resultados säo explicados em termos de comportamento adaptivo, relacionado com aptidäo. Um grau crítico de gordura seria necessário em fêmeas para permitir o inicío do ciclo reprodutivo. Em contraste, nenhuma resposta correlacionada foi evidente em machos relacionados. Eles näo diferiram dos controles em tgermos de porcentagem de gordura do adulto. Quando a seleçäo para tamanho corporal é feita de acordo com uma correlaçäo natural entgre peso corporal e comprimento do rabo, indivíduos selecionados seriam mais pesados porque seriam maiores e näo mais gordos. Isto permitiria uma exploraçäo mais efetiva da fonte de variância genética para peso corporal associado ao apetite, evitando a associaçäo com partiçäo. A conformaçäo do corpo, como descrito neste trabalho, pode ser um fator importante em programas de seleçäo para obter indivíduos menos pesados em produçäo de animais, especialmente porcos