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Due to the COVID-19 pandemic, many transport kits have been manufactured to preserve and transport nasopharyngeal swab samples (NPSs) from patients. However, there is no information on the performance of the different virus transport media (VTM) used in COVID-19 diagnosis in the population of Santiago de Chile. We compared the RT-qPCR amplification profile of five different viral transport kit mediums, including DNA/RNA Shield™, NAT, VTM-N, Ezmedlab™, and phosphate-buffered saline (PBS), for NPSs from Central Metropolitan Health Service, Santiago, Chile. The DNA/RNA Shield™ medium showed a better performance in terms of Cq and RFU values for the internal reference RNase P and viral ORF1ab probes. By contrast, the PBS transport medium registered higher Cq values for the viral and reference gene, compared to the other VTM. DNA/RNA Shield™ shows higher relative fluorescence units (RFUs) and lower Cq values for the reference gene. Collectively, our results suggest that the PBS medium could compromise the sample diagnosis because of its lower RT-qPCR performance. The NAT, Ezmedlab and VTM-N, and DNA/RNA Shield™ media show acceptable RT-qPCR parameters and, consequently, seem suitable for use in COVID-19 diagnosis.
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COVID-19 , COVID-19/diagnóstico , Teste para COVID-19 , Chile , Meios de Cultura , Humanos , Nasofaringe , Pandemias , RNA , RNA Viral/análise , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real , SARS-CoV-2/genética , Manejo de Espécimes/métodosRESUMO
The early detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using the real-time quantitative polymerase chain reaction (RT-qPCR) as a gold-standard molecular tool has allowed to test and trace the viral spread and the isolation of COVID-19-infected patients. The detection capacity of viral and internal genes is an essential parameter to consider and analyze during the assay. In this study, we analyze the performance of the two commercial RT-qPCR kits used in Chile, TaqMan™ 2019-nCoV Control Kit v1 (Thermo Fisher) and MaxCov19 (TAAG Genetics), for the COVID-19 diagnosis from nasopharyngeal swab samples (NPSs). Our results show a lower sensitivity of the TAAG kit compared to the Thermo Fisher kit, even in the detection of SARS-CoV-2 mutations associated with its variants. This study reinforces the relevance of evaluating the performance of RT-qPCR kits before being used massively since those with lower sensitivity can generate false negatives and produce outbreaks of local infections.
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Co-digestion of thermally pretreated sewage sludge with food waste is an innovative strategy that could improve the balance and availability of nutrients needed to increase the efficiency of anaerobic digestion in terms of biogas production. In this context, the aim of this research was to evaluate the impact of different proportions of sewage sludge/food waste in laboratory- and pilot-scale reactors. Special focus was placed on the impact of the variability of food waste composition on the behaviour of the pilot digester. Our results show that by adding 40% of co-substrate, a higher biogas production was possible during laboratory operation. Interestingly, using a co-substrate of variable composition had no negative impact on the reactor's stability at pilot-scale, promoting an increase in biogas production through a more efficient use of organic matter. In both the lab and pilot experiences there was an impact on the amount of nitrogen in the digestate compared to digester operating in monodigestion. This impact is more significant as the proportion of co-substrate rises. Overall, our results show that co-digestion of thermally pretreated sewage sludge with food waste allows better management of food waste, especially when their composition is variable.
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Eliminação de Resíduos , Esgotos , Anaerobiose , Biocombustíveis/análise , Reatores Biológicos , Digestão , Alimentos , Laboratórios , MetanoRESUMO
The ISAV has a genome composed of eight segments of (-)ssRNA, segment 6 codes for the hemagglutinin-esterase protein, and has the most variable region of the genome, the highly polymorphic region (HPR), which is unique among orthomyxoviruses. The HPR has been associated with virulence, infectivity and pathogenicity. The full length of the HPR is called HPR0 and the strain with this HPR is avirulent, in contrast to strains with deleted HPR that are virulent to varying degrees. The molecular mechanism that gives rise to the different HPRs remains unclear. Here, we studied in vitro the evolution of reassortant recombinant ISAV (rISAV) in Atlantic salmon head kidney (ASK) cells. To this end, we rescued and cultivated a set of rISAV with different segment 6-HPR genotypes using a reverse genetics system and then sequencing HPR regions of the viruses. Our results show rapid multiple recombination events in ISAV, with sequence insertions and deletions in the HPR, indicating a dynamic process. Inserted sequences can be found in four segments of the ISAV genome (segments 1, 5, 6, and 8). The results suggest intra-segmental heterologous recombination, probably by class I and class II template switching, similar to the proposed segment 5 recombination mechanism.
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Isavirus/genética , Isavirus/patogenicidade , Recombinação Genética , Animais , Linhagem Celular , Doenças dos Peixes/virologia , Genótipo , Hemaglutininas Virais/genética , Infecções por Orthomyxoviridae/virologia , Salmo salar , Análise de Sequência de DNA , Proteínas Virais de Fusão/genética , Virulência/genéticaRESUMO
To provide new insight into the dark fermentation process, a multi-lateral study was performed to study the microbiology of 20 different lab-scale bioreactors operated in four different countries (Brazil, Chile, Mexico, and Uruguay). Samples (29) were collected from bioreactors with different configurations, operation conditions, and performances. The microbial communities were analyzed using 16S rRNA genes 454 pyrosequencing. The results showed notably uneven communities with a high predominance of a particular genus. The phylum Firmicutes predominated in most of the samples, but the phyla Thermotogae or Proteobacteria dominated in a few samples. Genera from three physiological groups were detected: high-yield hydrogen producers (Clostridium, Kosmotoga, Enterobacter), fermenters with low-hydrogen yield (mostly from Veillonelaceae), and competitors (Lactobacillus). Inocula, reactor configurations, and substrates influence the microbial communities. This is the first joint effort that evaluates hydrogen-producing reactors and operational conditions from different countries and contributes to understand the dark fermentation process.
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Reatores Biológicos/normas , Fermentação , Hidrogênio/metabolismo , Consórcios Microbianos/genética , RNA Ribossômico 16S/genética , Anaerobiose , Clostridium/classificação , Clostridium/genética , Clostridium/metabolismo , Enterobacter/classificação , Enterobacter/genética , Enterobacter/metabolismo , Firmicutes/classificação , Firmicutes/genética , Firmicutes/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillus/classificação , Lactobacillus/genética , Lactobacillus/metabolismo , América Latina , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/metabolismo , Thermotoga maritima/classificação , Thermotoga maritima/genética , Thermotoga maritima/metabolismo , Veillonellaceae/classificação , Veillonellaceae/genética , Veillonellaceae/metabolismoRESUMO
Hydrogen production by dark fermentation is one promising technology. However, there are challenges in improving the performance and efficiency of the process. The important factors that must be considered to obtain a suitable process are the source of the inoculum and its pre-treatment, types of substrates, the reactor configurations and the hydrogen partial pressure. Furthermore, to obtain high-quality hydrogen, it is necessary to integrate an effective separation procedure that is compatible with the intrinsic characteristics of a biological process. Recent studies have suggested that a stable and robust process could be established if there was an effective selection of a mixed microbial consortium with metabolic pathways directly targeted to high hydrogen yields. Additionally, the integration of membrane technology for the extraction and separation of the hydrogen produced has advantages for the upgrading step, because this technology could play an important role in reducing the negative effect of the hydrogen partial pressure. Using this technology, it has been possible to implement a production-purification system, the 'hydrogen-extractive membrane bioreactor'. This configuration has great potential for direct applications, such as fuel cells, but studies of new membrane materials, module designs and reactor configurations are required to achieve higher separation efficiencies.
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Reatores Biológicos , Fermentação , Hidrogênio/isolamento & purificação , Hidrogênio/metabolismo , Membranas ArtificiaisRESUMO
Introduction: The COVID-19 pandemic is still in force, causing global public health challenges and threats. Although vaccination and herd immunity have proven to be the most efficient way to control the pandemic, massive and early testing of patients using the RT-qPCR technique is crucial for constant genomic surveillance. The appearance of variants of SARS-CoV-2 with new mutations can reduce the efficiency of diagnostic detection. In this sense, several commercial RT-qPCR kits have been the target of extensive analysis because low assay performance could lead to false-negative diagnoses. Methods: In this study, we evaluated the performance of three commercial RT-qPCR kits; Thermo Fisher (TaqMan 2019-nCoV Assay Kit v1), BGI and Roche (LightCycler® Multiplex RNA Virus Master) used for the diagnosis of COVID-19 throughout the pandemic in Santiago de Chile. Results: Under our best assay conditions, we found significant differences in Cq amplification values for control and viral probes, against the same nasopharyngeal swab samples (NPSs). In addition, in some cases, the sensitivity of the RT-qPCR kits decreased against viral variants. Conclusion: Our study suggests evaluating the RT-qPCR kits used to detect SARS-CoV-2 because variants such as Omicron, which has several mutations, can compromise their detection and underestimate viral circulation.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Pandemias , COVID-19/diagnóstico , Chile , Nasofaringe , RNA Viral/genética , RNA Viral/análise , Sensibilidade e EspecificidadeRESUMO
Sulfide produced by sulphate-reducing bacteria in anaerobic reactors can seriously affect biogas quality. Microaeration has become a reliable way to remove sulfide, by promoting its oxidation. However, limited research is available regarding its application in upflow anaerobic sludge bed (UASB) reactors. In this research, silicon membranes were studied as a mechanism to dose oxygen in USAB reactors. Two configurations were tested: the membrane placed inside the reactor or in an external module. Our results show that the external membrane proved to be a more practical alternative, providing conditions for sulfide oxidation. This led to a reduction in its concentration in the liquid effluent and biogas. External membrane configuration achieved a sulfide conversion rate of 2.4 g-S m2 d-1. Since the membrane was not sulfide-selective, methane losses were observed (about 9%). In addition, excessive oxygen consumption was observed, compared to the stoichiometric requirement. As is the case for many membrane-based systems, membrane area is a key factor determining the correct operation of the system.
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The objective of this study was to analyze the association of the level of physical activity (PA) and body composition in relation to the amount and distance of built environments favorable to the practice of PA in relation to the homes of adolescents in the city of Lagoa do Carro/Pernambuco, Brazil. A total of 289 adolescents (153 boys; 10 to 18 years) participated in the study, duly enrolled in schools municipality. The self-administered Physical Activity Questionnaire for Children (PAQ-C) and Physical Activity Questionnaire for Adolescent (PAQ-A) was used to assess the PA level. The Geographic Information System was used to assess the built environments. Buffers of 100 to 500 meters were created from the center of the built environment. The Artificial Neural Network in the Feedforward method was used to assess the association and importance of built environment and body composition variables with PA level. The different distances from the built environment to the place of residence do not present statistical differences. It is noteworthy that the number of buffers up to 500 meters away was the variable that showed the greatest importance for the PA level, along with adolescents who live in places with greater exposure in terms of built environments, being considered more active. It was possible to conclude that the main determinants of the PA level of adolescents were the amount of buffers at 500 meters, sex and the distance to the built environment. However, the variables, housing area, body mass and amounts of buffers at 100 meters were the ones with the lowest power of influence.
O objetivo deste estudo foi analisar a associação do nível de atividade física (AF) e composição corporal em relação à quantidade e distância de ambientes construídos favoráveis à prática da AF em relação ao domicílio de adolescentes da cidade de Lagoa do Carro/Pernambuco, Brasil. Participaram do estudo 289 adolescentes (153 meninos; 10 a 18 anos), devidamente matriculados nas escolas do município. O Physical Activity Questionnaire for Children (PAQ-C) e Physical Activity Questionnaire for Adolescent (PAQ-A) autoaplicável foram utilizados para avaliar o nível de AF. O Sistema de Informação Geográfico foi utilizado para avaliação dos ambientes construídos. Foram criados Buffers de 100 a 500 metros de raio a partir do centro do ambiente construído. A Rede Neural Artificial no método de Feedforward foi utilizada para analisar a associação e a importância das variáveis do ambiente construído e composição corporal com o nível de AF. Não foram observadas diferenças estatisticamente significativas entre o nível de AF e as distâncias do ambiente construído. Ressalta--se que a quantidade de buffers até 500 metros de distância, foi a variável que apresentou maior importância para o nível de AF, juntamente com os adolescentes que residem em locais com maior exposição em quantidade de ambientes construídos, sendo considerados mais ativos. Os principais determinantes do nível da AF dos adolescentes foram à quantidade de buffers a 500 metros, o sexo e a distância para o ambiente construído. Em contrapartida, as variáveis, zona de moradia, massa corporal e quantidades de buffers a 100 metros foram as que apresentaram um menor poder de influência.
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Electro-fermentation (EF) is a novel process that consists of electrochemically controlling microbial fermentative metabolism with electrodes. The electrodes can act as either electron sinks or sources that allow unbalanced fermentation. They can also modify the medium by changing the redox balance. Such electrochemical control exerts significant effects not only on microbial metabolism and cellular regulation but also on interspecies interactions and the selection of bacterial populations in mixed microbial cultures. In this paper we propose some basics and principles to better define the EF concept within the field of bioelectrochemistry. We also explore the up-to-date strategies to put EF into practice and propose hypothetical mechanisms that could explain the first EF results reported in the literature.