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Pedro Mercado Martinez - One of the best experts on this subject based on the ideXlab platform.
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sensibilidad de Listeria monocytogenes y Listeria ivanovii frente al aceite esencial de cocos nucifera
REVISTA REBIOL, 2017Co-Authors: Marylin Escalantepereda, Pedro Mercado MartinezAbstract:Se determino la sensibilidad de Listeria monocytogenes y Listeria ivanovii frente a cinco diferentes concentraciones del aceite esencial de Cocos nucifera . El aceite se obtuvo por el metodo de destilacion por arrastre con vapor de agua y, para determinar la sensibilidad antibacteriana, se emplearon cultivos de L. monocytogenes y de L. ivanovii los cuales fueron reactivados en Caldo Frasier por 18 horas a 37°C y estandarizadas al tubo N° 0.5 del Nefelometro de Mac Farland (1.5x10 8 ufc/mL). La actividad antibacteriana del aceite se determino utilizando tecnica de difusion en Agar en placa de Mueller-Hinton temperado a 45°C y las concentraciones del aceite al: 20%, 40%, 60%, 80% y 100%; asimismo, el antibiotico sulfametoxazol/trimetroprin como control positivo). La actividad antibacteriana se determino midiendo el halo de inhibicion alrededor de cada orificio: se considero inhibitorio un valor de 2mm. Se encontro que todas las cepas de L. monocytogenes y L. ivannovii presentaron sensibilidad frente a las cinco concentraciones empleadas del aceite esencial de C. nucifera (p<0,05). Palabras clave: Sensibilidad bacteriana, aceite esencial, Cocos nucifera , Listeria monocytogenes .
Vázquez Carlos - One of the best experts on this subject based on the ideXlab platform.
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A two-dimensional multi-species model for different Listeria monocytogenes biofilm structures and its numerical simulation
'Elsevier BV', 2020Co-Authors: Balsa-canto Eva, López-núñez Alejandro, Vázquez CarlosAbstract:[Abstract] In this work we propose a two-dimensional multi-species model to describe the dynamics of biofilms formed by the pathogenic bacteria Listeria monocytogenes. Different Listeria monocytogenes strains produce biofilms with different structures, namely flat, honeycomb and clustered. Previous works showed that glucose impaired uptake and the appearance of damaged or dead cells are critical mechanisms underlying Listeria monocytogenes biofilm dynamics. Here we explicitly propose an extension of the two-dimensional multi-species model proposed by Alpkist and Klapper to account for those mechanisms. The result is a continuous two-dimensional multi-species model with non-linear detachment and mass action nutrient consumption. Moreover, we also propose a set of efficient numerical methods to solve the coupled model and we have developed their computer implementation from scratch in C/C++. Mainly based on finite differences schemes, these numerical techniques include Crank-Nicolson schemes for time discretization, Gibou’s ghost node techniques and level set methods to cope with the free boundary associated to the determination of the time-dependent biofilm domain. To finish with, we compare our simulation results with the dynamics of real biofilms as observed in the laboratory. More precisely, by using model parameters calibrated to experiments, the numerical results clearly illustrate the performance of the proposed model and the numerical methods to reproduce the real dynamics of flat, clustered and honeycomb structures shown by different Listeria monocytogenes strains.Ministerio de Asuntos Económicos y Transformación Digital; MTM2016-76497-RXunta de Galicia; GRC2014/044Xunta de Galicia; ED431C2018/033Ministerio de Educación, Cultura y Deporte; FPU13/02191Xunta de Galicia; ED431G 2019/01Xunta de Galicia; IN607B 2017/0
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A two-dimensional multi-species model for different Listeria monocytogenes biofilm structures and its numerical simulation
'Elsevier BV', 2020Co-Authors: Balsa-canto Eva, López-núñez Alejandro, Vázquez CarlosAbstract:22 pages, 9 figures, 2 tables.-- Under a Creative Commons licenseIn this work we propose a two-dimensional multi-species model to describe the dynamics of biofilms formed by the pathogenic bacteria Listeria monocytogenes. Different Listeria monocytogenes strains produce biofilms with different structures, namely flat, honeycomb and clustered. Previous works showed that glucose impaired uptake and the appearance of damaged or dead cells are critical mechanisms underlying Listeria monocytogenes biofilm dynamics. Here we explicitly propose an extension of the two-dimensional multi-species model proposed by Alpkist and Klapper to account for those mechanisms. The result is a continuous two-dimensional multi-species model with non-linear detachment and mass action nutrient consumption. Moreover, we also propose a set of efficient numerical methods to solve the coupled model and we have developed their computer implementation from scratch in C/C++. Mainly based on finite differences schemes, these numerical techniques include Crank-Nicolson schemes for time discretization, Gibou’s ghost node techniques and level set methods to cope with the free boundary associated to the determination of the time-dependent biofilm domain. To finish with, we compare our simulation results with the dynamics of real biofilms as observed in the laboratory. More precisely, by using model parameters calibrated to experiments, the numerical results clearly illustrate the performance of the proposed model and the numerical methods to reproduce the real dynamics of flat, clustered and honeycomb structures shown by different Listeria monocytogenes strainsALN and CV acknowledge the funding by MINECO from Spanish Government (Grant MTM2016-76497-R) and by Xunta de Galicia (Grants GRC2014/044 and ED431C2018/033). ALN acknowledges FPU fellowship (FPU13/02191) from the Spanish Government program MECD-FPU. CV and ALN as members of CITIC also akcnowledge the grant ED431G 2019/01, funded by Consellería de Educación, Universidade e Formación Profesional of Xunta de Galicia through FEDER funds with 80%, from FEDER Galicia 2014-2020 Program and 20% from Secretaría Xeral de Universidades. EBC acknowledges funding from Contrato Programa and grant Ref. IN607B 2017/02 from Xunta de Galicia. All grants include FEDER fundsPeer reviewe
Escalante Pereda., Marylin Andrea - One of the best experts on this subject based on the ideXlab platform.
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Determinación de la Sensibilidad de Listeria monocytogenes y Listeria ivanovii frente a diferentes concentraciones del aceite esencial de Cocos nucifera.
Universidad Nacional de Trujillo, 2016Co-Authors: Escalante Pereda., Marylin AndreaAbstract:El presente trabajo tuvo por objetivo determinar la sensibilidad de Listeria monocytogenes y Listeria ivanovii, frente a diferentes concentraciones del aceite de Cocos nucifera. El aceite se obtuvo por el método de destilación por arrastre con vapor de agua y, para determinar la sensibilidad antibacteriana, se emplearon cultivos de Listeria monocytogenes y de Listeria ivanovii. La sensibilidad de éstos microorganismos se determinó por el método de difusión en agar, utilizándose concentraciones de 20%, 40%, 60%, 80% y 100% del aceite; utilizando al sulfametoxazol/trimetroprin como antibiótico control. En cuanto a la preparación de los inóculos bacterianos; los cultivos de Listeria monocytogenes y Listeria ivannovii fueron reactivados en Caldo Frasier por 18 horas a 37 °C. Se tomaron una pequeña cantidad de colonias estandarizadas al tubo N° 0.5 del Nefelómetro de Mac Farland (1.5x108 ufc/mL). La actividad antibacteriana del aceite de Cocos nucifera, se determinó utilizando técnica de difusión en Agar en placas, por triplicado. Las placas contenían agar Mueller-Hinton temperado a 45°C inoculado con una suspensión de cultivo bacteriano joven. A cada placa se le realizó 4 orificios de 4mm de diámetro cada uno utilizando un sacabocado estéril. A estos orificios se añadió 50uL de cada una de las concentraciones de aceite esencial y las placas se incubaron a 37°C durante 24 horas. La actividad antibacteriana del extracto acuoso se determinó midiendo el halo de inhibición alrededor de cada orificio. Se considera inhibitorio un valor de 2mm. También se realizó una placa control con el disco de antibiótico. El procesamiento y análisis de los resultados obtenidos para la actividad antibacteriana del aceite esencial de Cocos nuciferas que presenta para Listeria monocytogenes y Listeria ivannovii se efectuó mediante el programa SPSS versión 18.0. Se realizó ANAVA unifactorial, a los datos obtenidos para determinar si hay diferencias significativas. Finalmente, se demostró que todas las cepas de Listeria monocytogenes y Listeria ivannovii presentaron sensibilidad frente a las cinco concentraciones empleadas del aceite esencial de Cocos nucifera
Pascale Cossart - One of the best experts on this subject based on the ideXlab platform.
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Listeria monocytogenes a multifaceted model
Nature Reviews Microbiology, 2006Co-Authors: Melanie Anne Hamon, Helene Bierne, Pascale CossartAbstract:The elaborate and skilful host-cell manipulations of Listeria monocytogenes provide researchers with a powerful model system to study host–pathogen interactions, as well as bacterial pathophysiology and adaptation. In addition, L. monocytogenes can be used as a tool to explore fundamental cellular processes such as cytoskeletal dynamics and cellular adhesion.
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Listeria monocytogenes: a multifaceted model
Nature Reviews Microbiology, 2006Co-Authors: Mélanie Hamon, Helene Bierne, Pascale CossartAbstract:The opportunistic intracellular pathogen Listeria monocytogenes has become a paradigm for the study of host–pathogen interactions and bacterial adaptation to mammalian hosts. Analysis of L. monocytogenes infection has provided considerable insight into how bacteria invade cells, move intracellularly, and disseminate in tissues, as well as tools to address fundamental processes in cell biology. Moreover, the vast amount of knowledge that has been gathered through in-depth comparative genomic analyses and in vivo studies makes L. monocytogenes one of the most well-studied bacterial pathogens.
Jay D Wenger - One of the best experts on this subject based on the ideXlab platform.
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ribosomal dna fingerprinting of Listeria monocytogenes using a digoxigenin labeled dna probe
European Journal of Epidemiology, 1991Co-Authors: Lewis M Graves, B Swaminathan, Michael W Reeves, Jay D WengerAbstract:A nonisotopic ribosomal DNA fingerprinting technique was developed for the characterization of Listeria monocytogenes. Plasmid pKK3535 (a pBR322-derived plasmid containing rrnB ribosomal RNA operon of Escherichia coli) was labeled with digoxigenin-II-dUTP by random priming and used to probe EcoRI fragments of L. monocytogenes chromosomal DNA on nylon filters. The method was successfully applied to the characterization of two sets of patient and food isolates of L. monocytogenes.