173 research outputs found

    EzrA Contributes to the Regulation of Cell Size in Staphylococcus aureus

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    EzrA is a negative regulator of FtsZ in Bacillus subtilis, involved in the coordination between cell growth and cell division and in the control of the cell elongation–division cycle. We have now studied the role of the Staphylococcus aureus homologue of the B. subtilis EzrA protein and shown that it is not essential for cell viability. EzrA conditional and null mutants have an overall increase of the average cell size, compared to wild type strains. In the larger ezrA mutant S. aureus cells, cell division protein FtsZ and the cell wall synthesizing Penicillin Binding Proteins (PBPs) are not properly localized. This suggests that there may be a maximum cell diameter that allows formation of a Z-ring capable of recruiting the other components of the divisome and of driving cytokinesis. We propose that the major role of EzrA in S. aureus is in cell size homeostasis

    Selection of hydrotropes for enhancing the solubility of artemisinin in aqueous solutions

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    Artemisinin is an antimalarial substance very sparingly soluble in water. In the attempt to identify environmental-friendly and non-toxic aqueous-based solvents to extract it from Artemisia annua L., the solubility of artemisinin in aqueous solutions of different hydrotropes was measured at 303.2 K, for hydrotrope concentrations up to 5 M. The ability of the studied hydrotropes for enhancing the artemisinin solubility increases in the following order: Na[N(CN)2] < Na[SCN] < [Chol][Van] < [Chol][Gal] < [N4,4,4,4]Cl < [Chol][Sal] < [P4,4,4,4]Cl < Na[Sal], with Na[Sal] allowing an increase in the solubility of 750 fold compared to pure water. The COSMO-RS model and experimental Kamlet-Taft solvatochromic parameters were applied to connect the solubility enhancement with solvent properties. At low hydrotrope concentration, the solubility increases with the decreasing of the difference between the Apolar Factors of the hydrotrope and artemisinin, while for higher hydrotrope concentration, the hydrogen-bond acceptor character of the hydrotrope seems to have an impact on the solubility enhancement. Even if some mechanistic understanding is still to unfold, quantitatively the empirical correlations of solubility enhancement with the hydrotrope concentration and the solvatochromic parameters show very high accuracy. In particular, 93% of the change on the artemisinin solubility enhancement could be explained using the hydrotrope concentration and two combined solvatochromic parameters (αβ and π∗2) as explaining variables.This work was developed within the scope of the projects CICECOAveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, CIMO-Mountain Research Center, UIDB/00690/2020, and Green Health (Norte-01-0145-FEDER-000042) all financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 and NORTE 2020 Partnership Agreement. Isabela Sales and Silvana Mattedi thanks the finantial support from CAPES and CNPq/ Brazil (CAPES: Proc. 88881.189075/2018-01 and 88887.494428/2020- 00. CNPq: Grant 303089/2019-9 and Proc.438036/2018-2).info:eu-repo/semantics/publishedVersio

    Desenvolvimento de bases de informação para sistemas de informação aplicados ao ordenamento florestal

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    Sustainable forest planning involves the development of an information base that may adequately represent complex data and information relations. This paper presents a methodology designed to simplify the evolvement of such an information base. The development of a Regional Forest Plan is used as a case study. Characteristics of an information base such as dimension and diversity depend on the objectives of the planning process and on existing and available knowledge. Information availability and incomplete knowledge are often limiting factors that determine specific adaptations to the proposed methodology. For example, intensification of participatory mechanisms and effective communication may be key issues to promote knowledge acquisition. These adaptations, as well as the management of the information itself, can be enhanced and implemented with Information Systems (IS). IS may also be used to generate a more adequate representation of the complexity of the planning information base

    Overview of Membrane Science and Technology in Portugal

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    Funding Information: Acknowledgments: The authors acknowledge Tiago Araújo for his valuable contribution in writing—original draft preparation—the carbon molecular sieve membranes content. LCT is grateful to Fundação para a Ciência e a Tecnologia (FCT/MCTES) for her assistant researcher contract under Scientific Employment Stimulus (2020.01555.CEECIND). DMFS thanks FCT/MCTES for a research contract in the scope of programmatic funding UIDP/04540/2020. Funding Information: Funding: This work was supported by Associate Laboratory for Green Chemistry—LAQV, which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020), Research project PTDC/EQU-EPQ/29579/2017 funded by FCT/MCTES “Programa Operacional Regional de Lisboa, FEDER”, project Nanoart PTDC/CTM-BIO/6178/2014 and CeFEMA with grant number 325UID/CTM/04540/2013 funded by FCT/MCTES. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Membrane research in Portugal is aligned with global concerns and expectations for sustainable social development, thus progressively focusing on the use of natural resources and renewable energy. This review begins by addressing the pioneer work on membrane science and technology in Portugal by the research groups of Instituto Superior Técnico—Universidade de Lisboa (IST), NOVA School of Science and Technology—Universidade Nova de Lisboa (FCT NOVA) and Faculdade de Engenharia—Universidade do Porto (FEUP) aiming to provide an historical perspective on the topic. Then, an overview of the trends and challenges in membrane processes and materials, mostly in the last five years, involving Portuguese researchers, is presented as a contribution to a more sustainable water–energy–material–food nexus.publishersversionpublishe

    Classificação Geotécnica do maciço rochoso da Pedreira do Monte das Flores – Évora (Portugal)

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    No âmbito da atualização do processo de homologação da Pedreira do Monte das Flores - Évora, como fornecedora de balastro ferroviário, procedeu-se à classificação geotécnica do maciço rochoso existente no local. Esta exploração possui 96,90 ha de área arrendada estando 70,70 ha concessionados à exploração. Geologicamente, a área estudada pertence à Zona de Ossa-Morena (Maciço de Évora), enquanto parte integrante do Maciço Ibérico que constitui o setor mais ocidental e contínuo da Cadeia Orogénica Varisca na Europa. Também os eventos tectonotérmicos alpinos se fizeram sentir neste maciço de forma atenuada, permitindo a preservação da história geológica mesozóica [Moita, 2008]. A unidade geológica onde se insere a exploração é constituída por litótipos ígneos e metamórficos de idade precâmbrica e paleozóica [Andrade et al., 1976], denotando-se um domínio das formações de rochas eruptivas. Na área estudada ocorre um afloramento de quartzodiorito e granodiorito de grão médio, não porfiróide, onde os minerais mais representativos da rocha são o feldspato potássico, a plagioclase e o quartzo, sem evidenciarem qualquer orientação à vista desarmada [Moita, 2008]. Neste estudo fez-se a descrição geotécnica da qualidade do maciço rochoso que ocorre na Pedreira do Monte das Flores. Por se tratar de um sistema de classificação generalista e correntemente utilizado na avaliação do comportamento geomecânico dos maciços rochosos, utilizou-se a Descrição Geotécnica Básica (“Basic Geotechnical Description”- BGD), proposta pela Sociedade Internacional de Mecânica das Rochas [ISRM, 1981]. O principal objetivo da aplicação desta classificação foi o de efetuar um zonamento geotécnico do maciço rochoso, quer do local atualmente em exploração, quer da área contígua para onde se prevê o alargamento da corta da exploração, com base no reconhecimento geológico e, na amostragem efetuada em locais selecionados para posterior realização de ensaios laboratoriais de caracterização mecânica. Este reconhecimento geológico de superfície permitiu identificar o tipo de rocha presente, determinar as características estruturais e caracterizar a alteração do maciço rochoso, assim como, definir as diferentes famílias de fraturas presentes e quantificar o espaçamento entre as descontinuidades nestas famílias. Com o objetivo de determinar as características mecânicas, tais como, a resistência à compressão uniaxial e o ângulo de atrito das fraturas, foi realizada uma campanha de ensaios laboratoriais e de campo, nomeadamente, o ensaio de resistência à compressão uniaxial, complementado pelo ensaio de carga pontual, de modo a determinar o valor daquela resistência. Realizou-se também o ensaio com o martelo de Schmidt dado ser um ensaio simples e rápido na caracterização de materiais [Pinho, 2003], que permite estimar o valor da resistência à compressão uniaxial dos planos das descontinuidades do maciço rochoso (JCS), nos diferentes locais de amostragem. O parâmetro JCS, o coeficiente de rugosidade da descontinuidade (JRC) e a tensão efectiva normal (’n ), foram necessários para obter o ângulo de atrito das diaclases (Øpico), de acordo com o método proposto pela Sociedade Internacional de Mecânica das Rochas [ISRM, 1978]. O estudo realizado permitiu concluir que o maciço apresenta boa qualidade, em regra, homogénea relativamente às suas características geológicas e geotécnicas. No entanto, distinguem-se duas zonas, ZG1 e ZG2, com base em pequenas diferenças nos valores da resistência à compressão uniaxial da rocha e do ângulo de atrito das fraturas

    A comparative genomics approach for identifying host-range determinants in <i>Streptococcus thermophilus</i> bacteriophages

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    The authors would like to thank: Mimi Birkelund, Ditte E. Christiansen, Goncalo Covas, and Denise Coutinho for their help in collecting data; Ana Rute Neves for valuable discussions; Witold Kot and Lars H. Hansen for sequencing of phage genomes at Aarhus University (Roskilde, Denmark). This work is part of an Industrial PhD Project funded by Innovation Fund Denmark and Chr. Hansen A/S, grant no. 4135-00104B.Comparative genomics has proven useful in exploring the biodiversity of phages and understanding phage-host interactions. This knowledge is particularly useful for phages infecting Streptococcus thermophilus, as they constitute a constant threat during dairy fermentations. Here, we explore the genetic diversity of S. thermophilus phages to identify genetic determinants with a signature for host specificity, which could be linked to the bacterial receptor genotype. A comparative genomic analysis was performed on 142 S. thermophilus phage genomes, 55 of which were sequenced in this study. Effectively, 94 phages were assigned to the group cos (DT1), 36 to the group pac (O1205), six to the group 5093, and six to the group 987. The core genome-based phylogeny of phages from the two dominating groups and their receptor binding protein (RBP) phylogeny corresponded to the phage host-range. A role of RBP in host recognition was confirmed by constructing a fluorescent derivative of the RBP of phage CHPC951, followed by studying the binding of the protein to the host strain. Furthermore, the RBP phylogeny of the cos group was found to correlate with the host genotype of the exocellular polysaccharide-encoding operon. These findings provide novel insights towards developing strategies to combat phage infections in dairies.publishersversionpublishe

    Enhancing artemisinin solubility in aqueous solutions: searching for hydrotropes based on ionic liquids

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    Artemisinin is a sesquiterpenoid lactone peroxide, known for its potent antimalarial activity that can be extracted from Artemisia annua L. This compound is only sparingly soluble in water, making its extraction using environmental-friendly and non-toxic aqueous solvents difficult. In the attempt to overcome this limitation, hydrotropes, which are a class of compounds that can assist in increasing the solubility of hydrophobic solutes in water, were investigated in this work. In particular, the hydrotropic capability of ionic liquids (ILs) on the aqueous solubility of artemisinin was studied. The effects of IL concentration and anion nature of 1-butyl-3-methylimidazolium-based ILs on the solubility of artemisinin at 303.2 K in water were evaluated. It is here shown the excellent capacity of ILs containing thiocyanate or dicyanamide anions to enhance the solubility of artemisinin in aqueous media, with a magnitude comparable to that obtained with the best organic solvents. Furthermore, solvatochromic parameters of the ILs aqueous solutions were also measured and combined with COSMO-RS and the cooperative hydrotropy model to establish relations between the artemisinin solubility enhancement and the solvent characteristics. The solubility enhancement of artemisinin is favored by the apolarity of the medium and the lower hydrogen-bond acceptor character of the hydrotrope.This work was developed within the scope of the projects CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, CIMO-Mountain Research Center, UIDB/00690/2020, all financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. Isabela Sales and Silvana Mattedi thanks the finantial support from CAPES and CNPq/Brazil (CAPES: Proc. 88881.189075/2018-01 and 88887.494428/2020-00. CNPq: Grant 303089/2019-9 and Proc.438036/2018-2).info:eu-repo/semantics/publishedVersio

    Availability and Nutritional Composition of Street Food in Urban Central Asia: Findings From Almaty, Kazakhstan

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    Objective: To describe the availability and nutritional composition of commonly available street foods in Almaty, Kazakhstan. Methods: 384 street food vending sites (in 10 public markets) were assessed; information on vending sites characteristics and food availability and samples of the most commonly available street foods (81 homemade; 40 industrial) were collected for chemical analysis. Results: Fruit, beverages and food other than fruit were available in 1.0%, 47.4% and 92.7% of all vending sites. Homemade food other than fruit (e.g., bread, main dishes, snacks, pastries, sandwiches, and cakes) were available in 63.4% of stationary vending sites, while industrial (e.g., snacks, chocolate, cakes, and cookies) in 45.6% of them. Industrial foods were the most energy-dense [median kcal/100 g: 438.8 vs. 267.2, p < 0.001 (homemade)]. Traditional homemade dishes were high in sodium, reaching 2,248 mg/serving (lagman) and major contributors of protein and fat to energy content (shashlik: 22.8% from protein, 68.3% from fat). Industrial chocolate and homemade cake presented the highest saturated (14.6 g/serving) and trans-fat (3.20 g/serving) contents. Conclusion: These findings advocate for the implementation of health promotion strategies targeted at vendors, consumers and other stakeholders. Copyright (c) 2022 Albuquerque, Lança de Morais, Gelormini, Sousa, Casal, Pinho, Damasceno, Moreira, Breda, Lunet and Padrão

    Patterns of Street Food Purchase in Cities From Central Asia

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    Street food makes a significant contribution to the diet of many dwellers in low- and middle-income countries and its trade is a well-developed activity in the central Asian region. However, data on its purchase and nutritional value is still scarce. This study aimed to describe street food purchasing patterns in central Asia, according to time and place of purchase. A multicentre cross-sectional study was conducted in 2016/2017 in the main urban areas of four central Asian countries: Dushanbe (Tajikistan), Bishkek (Kyrgyzstan), Ashgabat (Turkmenistan) and Almaty (Kazakhstan). Street food markets (n = 34) and vending sites (n = 390) were selected by random and systematic sampling procedures. Data on the purchased foods and beverages were collected by direct observation. Time and geographic location of the purchases was registered, and their nutritional composition was estimated. A total of 714 customers, who bought 852 foods, were observed. Customers' influx, buying rate and purchase of industrial food were higher in city centers compared to the outskirts (median: 4.0 vs. 2.0 customers/10 min, p < 0.001; 5.0 vs. 2.0 food items/10 min, p < 0.001; 36.2 vs. 28.7%, p = 0.004). Tea, coffee, bread and savory pastries were most frequently purchased in the early morning, bread, main dishes and savory pastries during lunchtime, and industrial products in the mid-morning and mid-afternoon periods. Energy and macronutrient density was highest at 11:00-12:00 and lowest at 09:00-10:00. Purchases were smaller but more energy-dense in city centers, and higher in saturated and trans-fat in the peripheries. This work provides an overview of the street food buying habits in these cities, which in turn reflect local food culture. These findings from the main urban areas of four low- and middle-income countries which are currently under nutrition transition can be useful when designing public health interventions customized to the specificities of these food environments and their customers
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