30 research outputs found

    Trehalose biosynthesis in Thermus thermophilus RQ-1: biochemical properties of the trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase

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    The genes for trehalose synthesis in Thermus thermophilus RQ-1, namely otsA [trehalose-phosphate synthase (TPS)], otsB [trehalose-phosphate phosphatase (TPP)], and treS [trehalose synthase (maltose converting) (TreS)] genes are structurally linked. The TPS/TPP pathway plays a role in osmoadaptation, since mutants unable to synthesize trehalose via this pathway were less osmotolerant, in trehalose-deprived medium, than the wild-type strain. The otsA and otsB genes have now been individually cloned and overexpressed in Escherichia coli and the corresponding recombinant enzymes purified. The apparent molecular masses of TPS and TPP were 52 and 26 kDa, respectively. The recombinant TPS utilized UDP-glucose, TDP-glucose, ADP-glucose, or GDP-glucose, in this order as glucosyl donors, and glucose-6-phosphate as the glucosyl acceptor to produce trehalose-6-phosphate (T6P). The recombinant TPP catalyzed the dephosphorylation of T6P to trehalose. This enzyme also dephosphorylated G6P, and this activity was enhanced by NDP-glucose. TPS had an optimal activity at about 98°C and pH near 6.0; TPP had a maximal activity near 70°C and at pH 7.0. The enzymes were extremely thermostable: at 100°C, TPS had a half-life of 31 min, and TPP had a half-life of 40 min. The enzymes did not require the presence of divalent cations for activity; however, the presence of Co 2+ and Mg 2+ stimulates both TPS and TPP. This is the first report of the characterization of TPS and TPP from a thermophilic organism

    Sustainable starch-based edible films with agrifood residues as potential carriers for the probiotic Lactobacillus rhamnosus

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    Acknowledgments This work was supported by “Santander Universidades and University of Coimbra” through the project “Projetos Semente Santander UC: Era Pos-COVID-19: ´ uma sociedade mais sustentavel, ´ resiliente e justa” and by Fundaçao ˜ para a Ciˆencia e a Tecnologia (FCT): FCT/MCTEs (UIDB/00102/2020 and UIDP/00102/2020, of CIEPQPF, UIDB/04539/2020, UIDP/04539/2020 and LA/P/0058/2020, of CIBB, and UI/ 05704/2020 of ciTechCare. M. C. Gaspar acknowledges FCT for the financial support through the Institutional Scientific Employment Stimulus (CEECINST/00060/2021).Edible films are promising carriers for probiotics and can be composed by agrifood residues, which are usually rich in polymers and bioactive compounds. In this work, starch-based films were enriched with three types of agrifood residues (quince, potato and orange peels) and the incorporation of the probiotic Lactobacillus rhamnosus was studied, as well as the addition of inulin as a protective prebiotic. The resulting films were characterized in terms of mechanical properties, physicochemical properties, lactobacilli viability and microbiological properties. The mechanical properties of the films generally decreased with the introduction of L. rhamnosus, although this was highly dependent on the film composition. All films exhibited water vapor permeabilities in the typical range of starch-based films and were not greatly affected by the inclusion of probiotics. The loss of probiotic viability during films production was strongly related to the pH of the film-forming solutions. Films with agrifood residues had a slower loss of probiotic viability during storage, when compared to plain starch films, which may be explained by the presence of antioxidant compounds. Inulin was expected to improve viability, but this was not observed. Microbiological analysis showed that agrifood residues powders contained natural contaminant bacteria that were partially eliminated during film formation. Moreover, none of the target foodborne pathogens were detected in the analyzed samples. Overall, the results suggest that edible films containing agrifood residues can be a promising material for the delivery of probiotics and/or as primary packaging for some food products.info:eu-repo/semantics/publishedVersio

    A review on urinary tract infections diagnostic methods: Laboratory-based and point-of-care approaches

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    Urinary tract infections (UTIs) are among the most common infectious diseases worldwide. This type of infections can be healthcare-associated or community-acquired and affects millions of people every year. Different diagnostic procedures are available to detect pathogens in urine and they can be divided into two main categories: laboratory-based and point-of-care (POC) detection techniques. Traditional methodologies are often timeconsuming, thus, achieving a rapid and accurate identification of pathogens is a challenging feature that has been pursued by many research groups and companies operating in this area. The purpose of this review is to compare and highlight advantages and disadvantages of the traditional and currently most used detection methods, as well as the emerging POC approaches and the relevant advances in on-site detection of pathogens ' mechanisms, suitable to be adapted to UTI diagnosis. Lately, the commercially available UTI self-testing kits and devices are helping in the diagnosis of urinary infections as patients or care givers are able to perform the test, easily and comfortably at home and, upon the result, decide when to attend an appointment/Urgent Health Care Unit.info:eu-repo/semantics/publishedVersio

    The looming tide of nontuberculous mycobacterial infections in Portugal and Brazil

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    Nontuberculous mycobacteria (NTM) are widely disseminated in the environment and an emerging cause of infectious diseases worldwide. Their remarkable natural resistance to disinfectants and antibiotics and an ability to survive under low-nutrient conditions allows NTM to colonize and persist in man-made environments such as household and hospital water distribution systems. This overlap between human and NTM environments afforded new opportunities for human exposure, and for expression of their often neglected and underestimated pathogenic potential. Some risk factors predisposing to NTM disease have been identified and are mainly associated with immune fragilities of the human host. However, infections in apparently immunocompetent persons are also increasingly reported. The purpose of this review is to bring attention to this emerging health problem in Portugal and Brazil and to emphasize the urgent need for increased surveillance and more comprehensive epidemiological data in both countries, where such information is scarce and seriously thwarts the adoption of proper preventive strategies and therapeutic options.We acknowledge the support of FEDER through COMPETE and of National Funds through FCT - Fundacao para a Ciencia e a Tecnologia grants FCOMP-01-0124-FEDER-028359 [PTDC/BIA-MIC/2779/2012] and UID/NEU/04539/2013.info:eu-repo/semantics/publishedVersio

    Gestión del procedimiento de la higiene de las manos por enfermeros: desafíos para la salud colectiva

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    Objective: To describe the determining factors in hand hygiene management among nurses and identify associated collective health challenges. Method: Cross-sectional descriptive study. Data were collected using a questionnaire that was applied in four internal medicine units of a hospital of reference in Portugal. Results: The sample was composed of 50 nurses aged 26 to 55 years (mean age of 34.88 years); 80% were women, 58% had a Bachelor’s degree, and had 5-30 years of nursing practice (X̄ =11.94;±5.92). The vast majority of nurses (90%) reported complying with the existing recommendations on hand hygiene in pre-established moments. However, none of the nurses were able to identify all the moments for hand hygiene using water and soap or alcohol-based handrub. Conclusion: This study shows that continuous training, adequate materials/structures in the units, and redesigned administration/supervision practices are determining factors to achieve higher levels of adherence to hand hygiene among nurses, as well as increased quality and safety in care delivery, which is a current collective health challenge. Descriptors: Health Services Administration; Hand Hygiene; Nurses; Infection Control; Public Health NursingObjectivo: Descrever fatores determinantes na gestão da higiene das mãos por Enfermeiros e identifi car desafi os inerentes para a saúde coletiva. Método: Estudo descritivo-transversal. Dados coletados por questionário em quatro unidades de medicina interna de um hospital de referência em Portugal. Resultados: incluídos 50 enfermeiros, idade média 34,88 anos (entre os 26 e 55 anos), 80% sexo feminino, 58% são licenciados e exercem funções entre 5-30 anos (X=11.94;±5.92). Destes, 90% considera respeitar as recomendações existentes sobre higiene das mãos nos momentos estipulados para o efeito. Porém, nenhum dos momentos para a realização deste procedimento, com água e sabão ou solução antissética de base alcoólica, foi identifi cado por todos os enfermeiros. Conclusão: Contribuições como formação contínua, adequação dos materiais/estruturas das unidades e reconstrução de práticas por gestores/supervisores emergem neste trabalho como fatores determinantes para atingir níveis superiores de adesão à higiene das mãos por enfermeiros, de qualidade e segurança, desafi o atual para a saúde pública.Describir los factores determinantes en la gestión de la higiene de las manos por enfermeros e identifi car los desafíos inherentes para la salud colectiva. Método: Estudio descriptivo-transversal. Los datos se recogieron mediante un cuestionario en cuatro unidades de medicina interna de un hospital de referencia en Portugal. Resultados: se incluyó a 50 enfermeros con una edad media de 34,88 años (entre los 26 y 55 años), el 80 % del sexo femenino, el 58 % son licenciados y desempeñan sus funciones de 5 a 30 años (X = 11.94; ± 5.92). De ellos, el 90 % considera que respeta las recomendaciones existentes sobre higiene de las manos en los momentos estipulados para tal efecto. Sin embargo, los enfermeros no identificaron ninguno de los momentos para realizar este procedimiento, con agua y jabón o solución antiséptica de base alcohólica. Conclusión:Las contribuciones como formación continua, adecuación de los materiales / estructuras de las unidades y reconstrucción de prácticas por gestores / supervisores emergen en este trabajo como factores determinantes para alcanzar niveles superiores de adhesión a la higiene de las manos por enfermeros, de calidad y seguridad, un desafío actual para la salud pública.info:eu-repo/semantics/publishedVersio

    Relevance of mannosyglycerate and trehalose accumulation in the osmoadaptation of Thermus thermophilus

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    Tese de doutoramento em Biologia (Microbiologia) apresentada à Fac. Ciências e Tecnologia da Univ. Coimbr
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