101 research outputs found

    Evaluation of physiological effects induced by manuka honey upon staphylococcus aureus and escherichia coli

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    Several studies have explored the antimicrobial properties of manuka honey (MkH). However, the data available regarding antibacterial action mechanisms are scarcer. The aim of this study was to scrutinize and characterize primary e ects of manuka honey (MkH) upon the physiological status of Staphylococcus aureus and Escherichia coli (as Gram-positive and Gram-negative bacteria models, respectively), using flow cytometry (FC) to reveal its antibacterial action mechanisms. E ects of MkH on membrane potential, membrane integrity and metabolic activity were assessed using di erent fluorochromes in a 180 min time course assay. Time-kill experiments were carried out under the same conditions. Additionally, MkH e ect on e ux pumps was also studied in an E. coli strain with an over-expression of several e ux pumps. Exposure of bacteria to MkH resulted in physiological changes related to membrane potential and membrane integrity; these e ects displayed slight di erences among bacteria. MkH induced a remarkable metabolic disruption as primary physiological effect upon S. aureus and was able to block effux pump activity in a dose-dependent fashion in the E. coli strain.This work was supported by the Consejería de Sanidad of Junta de Castilla y León; under grant GRS 551/A/10. Patricia Combarros-Fuertes was funded by Consejería de Educación of Junta de Castilla y León and European Social Fund.info:eu-repo/semantics/publishedVersio

    Antibacterial action mechanisms of honey: physiological effects of avocado, chestnut, and polyfloral honey upon Staphylococcus aureus and Escherichia coli

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    Numerous studies have explored the antibacterial properties of di erent types of honey from all around the world. However, the data available describing how honey acts against bacteria are few. The aim of this study was to apply a flow cytometry (FC) protocol to examine and characterize the primary e ects of three varieties of honey (avocado, chestnut and polyfloral) upon physiological status of Staphylococcus aureus and Escherichia coli cells to reveal their antibacterial action mechanisms. The e ects of honey samples on membrane potential, membrane integrity, and metabolic activity were assessed using di erent fluorochromes, in a 180 min time course assay. Time-kill experiments were also carried out under similar conditions. Exposure of S. aureus and E. coli to the distinct honey samples resulted in physiological changes related to membrane polarization and membrane integrity. Moreover, honey induced a remarkable metabolic disruption as primary physiological e ect upon S. aureus. The di erent honey samples induced quite similar e ects on both bacteria. However, the depth of bacteria response throughout the treatment varied depending on the concentration tested and among honey varieties, probably due to compositional di erences in the honey.This work was supported by the Consejería de Sanidad of Junta de Castilla y León; under Grant GRS 551/A/10. Patricia Combarros-Fuertes was funded by Consejería de Educación of Junta de Castilla y León and European Social Fund.info:eu-repo/semantics/publishedVersio

    Seguimiento continuado de un caso real de hundimiento de los bloques de hormigón de un dique sumergido

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    Para el diseño de obras marítimas construidas sobre fondos arenosos, suele hacerse una estimación del hundimiento de la misma para colocar un exceso de material que compense dicho efecto y permita mantener el francobordo de diseño. La gran repercusión económica de este fenómeno ha justificado el que se haya estudiado en ensayos de laboratorio la influencia de los procesos de socavación y/o licuefacción en el hundimiento de bloques o escolleras. Para un listado actualizado de los numerosos investigadores implicados y de sus respectivas publicaciones,puede acudirse a Sumer (2014). Sin embargo, debe destacarse que hay muy pocos datos sobre el hundimiento de bloques o escolleras en casos reales (una tabla recopilatoria puede consultarse en Muñoz-Perez et al., 2015). Más aún, que los autores conozcan, no se habían publicado hasta el momento datos continuados en el tiempo del descenso de bloques. El objetivode esta ponencia es la presentación de una metodología que permite el seguimiento continuado del hundimiento de bloques así como de los resultados obtenidos en el caso real de un dique sumergido

    Microwave-Assisted Synthesis of Covalent OrganicFrameworks: A Review

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    This is the peer reviewed version of the following article: B. Díaz de Greñu, J. Torres, J. García-González, S. Muñoz-Pina, R. de los Reyes, A. M. Costero, P. Amorós, J. V. Ros-Lis, ChemSusChem 2021, 14, 208, which has been published in final form at https://doi.org/10.1002/cssc.202001865. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Covalent organic frameworks (COFs) are relatively recent materials. They have received great attention due to their interesting properties. However, the application of microwaves in their synthesis, despite its advantages such as faster and more reproducible processes, is a minority. Herein, a comprehensive compilation of the research results published in the microwave-assisted synthesis (MAS) of COFs is presented. This review includes articles of 2D and 3D COFs prepared using microwaves as source of energy. The articles have been classified depending on the functional groups including boronate ester, imines, enamines, azines, and triazines, among others. It compiles the main parameters of synthesis and characteristics of the materials together with some general issues related with COFs and microwaves. Additionally, current and future perspectives of the topic have been discussed.This research was funded by the Spanish Ministerio de Ciencia, Innovacion y Universidades (RTI2018-100910-B-C44, RTI2018-100910-B-C42 and PEJ2018-004586-A), and the Generalitat Valenciana (CPTTGENT2018/004 and APOTIP/2019/A/023).Díaz De Greñu, B.; Torres, J.; García-González, J.; Muñoz-Pina, S.; De Los Reyes, R.; Costero, AM.; Amorós, P.... (2021). Microwave-Assisted Synthesis of Covalent OrganicFrameworks: A Review. ChemSusChem. 14(1):208-233. https://doi.org/10.1002/cssc.202001865S20823314

    Canopy arthropod declines along a gradient of olive farming intensification

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    Arthropod declines have been linked to agricultural intensification. However, information about the impacts of intensification is still limited for many crops, as is our understanding of the responses of different arthropod taxa and trophic groups, thus hindering the development of effective mitigation measures. We investigated the impacts of olive farming intensification on canopy-dwelling arthropods in the Mediterranean region. Intensification involves the increased use of agrochemicals, mechanisation and irrigation, but also structural changes from traditional orchards with low densities of large and old trees, to intensive and superintensive orchards with high to very high densities of smaller and younger trees, respectively. Canopy arthropods were vacuum-sampled at 53 sites representing the three orchard intensification levels, in spring, summer and autumn 2017. We evaluated how the arthropod community varied across intensification levels, and in response to orchard structure, management and landscape context. We found no changes in the diversity of arthropod taxa across intensification levels after correcting for sample coverage, but arthropod abundance declined markedly along the intensification gradient. Decreased abundance was associated with changes in orchard structure, lower herbaceous cover, and higher herbicide and insecticide use. The abundance of a specialized olive pest was lower in landscapes with higher woodland cover. The negative effects of intensification were stronger in spring and summer than in autumn, and parasitoids and predators were particularly affected. Overall, results suggest that retaining herbaceous cover, reducing agrochemical inputs and preserving natural woody elements in the landscape, may contribute to mitigate impacts of olive farming intensification on canopy arthropods, particularly on beneficial species
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