Colonización fungica de lentes de contacto

En la presente tesis doctoral se han estudiado los factores implicados en el proceso de colonización fúngica (adhesión e invasión) de lentes de contacto nuevas y procedentes de usuarios.Para ello se ha diseñado una fase experimental en la que se han observado, mediante microscopía óptica, las lentes procedentes de usuarios a fin de determinar la presencia o ausencia de hongos. Cuando se detectaron, y para poder proceder a su identificación taxonómica, se procedió a la realización de cultivos.Las lentes nuevas fueron cultivadas con diferentes cepas de hongos y se valoró la frecuencia y densidad de colonización según las condiciones de cultivo establecidas.La caracterización morfológica de las diferentes especies fúngicas, experimentadas y encontradas, se realizó utilizando microscopía óptica, confocal y electrónica de barrido.Los resultados obtenidos indican que: el 11,82% de las lentes procedentes de usuarios mostraban contaminación. Entre los hongos contaminantes encontrados se describen tres nuevas citas, Gliomastix, Humicola y Phoma. Así mismo, se ha establecido que únicamente las cepas 93150 de Candida albicans y 2700 de Aspergillus niger fueron cepas de colonizar las lentes nuevas.Por otra parte, se ha comprobado que la composición de los medios de cultivo, su evaporación y las características quimicas de las lentes (ionicidad e hidrofilia), son factores que influyen en la frecuencia de colonización y en la densidad de las hifas invasoras.Finalmente, la microscopía confocal por reflexión de luz ha permitido visualizar las colonias internas y su grado de penetración en el material de la lente.Las conclusiones obtenidas representan una contribución al conocimiento de los fenómenos determinantes del desarrollo de hongos en los diferentes polímeros estudiados. Suponen, además, un avance en el campo de la contactología clínica y explican algunos de los problemas

Optimizing the production of the biosurfactant lichenysin and its application in biofilm control

Aims: Apply response surface methodology (RSM) to develop and optimize an economical medium for lichenysin production, which is a surfactant produced by Bacillus licheniformis and evaluate the application of lichenysin in the prevention and disruption of pathogenic micro-organism biofilm that creates health problems in the food industry and hospitals. Results: An economical medium containing molasses was optimized to enhance lichenysin production by RSM. A production of 3.2 g l 1 of lichenysin was achieved with an optimum medium containing 107.82 g l 1 of molasses, 6.47 g l 1 of NaNO3 and 9.7 g l 1 of K2HPO4/KH2PO4, in which molasses and phosphate salts had a significant effect on biosurfactant production. Lichenysin was effectively applied in a surface pre-treatment to avoid microbial biofilm development of methicillin-resistant Staphylococcus aureus (MRSA) (68.73%) and Candida albicans (74.35%), with ED50 values of 8.3 and 17.2 lg ml 1 respectively. It was also very efficient in a surface posttreatment to remove biofilms of MRSA (55.74%) and Yersinia enterocolitica (51.51%), with an ED50 of 2.79 and 4.09 lg ml 1 respectively. Conclusions: Lichenysin was found to have notable anti-adhesion activity, being able to prevent and eliminate the biofilm formation by pathogenic strains associated with foodborne illness. This new medium resulted in a fourfold increase in production compared with the nonoptimized medium. Significance and Impact of the Study: Molasses can be regarded as a useful resource for biotechnological applications, such as the production of lichenysin. The use of agro-industrial substrates has an important role in the sustainable and competitive development of several industrial sectors, as well as in industrial residues management. Additionally, lichenysin is particularly effective in preventing biofilm formation by strains problematic for the food industry and in the hospital environment. Lichenysin also efficiently disrupts biofilm

Amino-acid-based surfactants: New antimicrobial agents

The rapid increase of drug resistant bacteria makes necessary the development of new antimicrobial agents. Synthetic amino acid-based surfactants constitute a promising alternative to conventional antimicrobial compounds given that they can be prepared from renewable raw materials. In this review, we discuss the structural features that promote antimicrobial activity of amino acid-based surfactants. Monocatenary, dicatenary and gemini surfactants that contain different amino acids on the polar head and show activity against bacteria are revised. The synthesis and basic physico-chemical properties have also been included

Green Catanionic Gemini Surfactant-Lichenysin Mixture: Improved Surface, Antimicrobial, and Physiological Properties

Catanionic surfactant mixtures form a wide variety of organized assemblies and aggregates with improved physicochemical and biological properties. The green catanionic mixture (NN omega)-N-alpha-Bis(N(alpha)caproylarginine) alpha,omega-propyldiamide (C-3(CA)(2)):Lichenysin (molar ratio 8:2) showed antimicrobial synergies against Yersinia enterocolitica, Bacillus subtilis, Escherichia coli O157:H7, and Candida albicans. Flow cytometry and viability studies indicated that this catanionic mixture increases the probability of Y. enterocolitica (38.2%) and B. subtilis (17.1%) cells entering a viable but nonculturable state. Zeta potential showed that one of the cationic charges of C-3(CA)(2) is neutralized by Lichenysin. An isotherm study demonstrated the formation of a stable aggregate between the two surfactants. The catanionic aggregate was able to interact with bacterial phospholipids. The lowest hemolysis (22.1 mu M) was obtained with the catanionic mixture, although an irritant potential (0.70) was characterized. According to the therapeutic index, the C-3(CA)(2):Lichenysin mixture was the formulation least toxic to eukatyotic cells. Partial neutralization of C-3(CA)(2) by Lichenysin modified the mode of action that enhances the transition of bacterial cells into a viable but nonculturable state (VBNC) and improved the cell selectivity. KEYWORDS:antimicrobial activity catanionic mixtures biosurfactant Lichenysin gemini surfactants flow cytometry VBNC Langmuir balanc

Lichenysin-geminal amino acid-based surfactants: Synergistic action of an unconventional antimicrobial mixture

Recently it has been demonstrated that catanionic mixtures of oppositely charged surfactants have improved physicochemical-biological properties compared to the individual components. Isotherms of mixtures of an anionic biosurfactant (lichenysin) and a cationic aminoacid surfactant (C-3(LA)(2)) indicate a strong interaction suggesting the formation of a new 'pseudo-surfactant'. The antimicrobial properties of the mixture lichenysin and C-3(LA)(2) M80:20, indicate a synergistic effect of the components. The mechanism of action on the bacterial envelope was assessed by flow cytometry and Transmission Electron Microscopy. (C) 2016 Elsevier B.V. All rights reserved. Keywords: Antimicrobial properties; Arginine; Escherichia coli; Flow cytometry; Gemini surfactants; Lichenysin; Listeria nonocytogenes; Potassium leakage; Transmission electron microscopy

Azimuthal asymmetry of direct photons in intermediate energy heavy-ion collisions

Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter phase. In this work, we have presented a first calculation of azimuthal asymmetry, characterized by directed transverse flow parameter $F$ and elliptic asymmetry coefficient $v_2$, for proton-neutron bremsstrahlung hard photons in intermediate energy heavy-ion collisions. The positive $F$ and negative $v_2$ of direct photons are illustrated and they seem to be anti-correlated to the corresponding free proton's flow.Comment: 7 pages, 4 figures; accepted by Physics Letters

Lichenysin production and application in the pharmaceutical field

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/103042Lipopeptides such as lichenysin are biosurfactants of great interest, due to the demand for natural surface-active agents with low toxicity. Bacillus licheniformis AL 1.1 produces a lipopeptide characterized as lichenysin (LchAL1.1), which acts as a powerful surfactant, able to reduce surface tension to 28.5 mN m-1 and with a critical micelle concentration of 15 mg L-1. LchAL1.1 is particularly effective in preventing biofilm formation by pathogenic strains, has an emulsifying capacity and permeabilizes membranes by a colloid-osmotic process. The production of lipopeptides from agro-industrial residues, particularly molasses, is a sustainable process of great potential for the development of economic bioprocesses

Experiencia de la escuela itinerante de derechos humanos para las mujeres de la Ciudad de México, 2016 a 2018

La Constitución Política de México menciona que todas y todos tenemos derechos a educación, trabajo digno, a servicios de salud y más, la población femenina es del 51.4% en la República Mexicana; las mujeres representamos el 52.6% (4,687,003) del total de población de la Ciudad de México, siendo el 62.8% de mujeres que tienen 15 años y más de lo anterior el 95.8% son alfabetas y se tiene sin instrucción en primaria un 6.8%, secundaria y medio superior un 18.7% y de superior y el 16.1 % a nivel superior. Por lo anterior se generó la escuela itinerante de derechos humanos para las mujeres de la Ciudad de México, teniendo como objetivo explicar los derechos humanos y de las mujeres para que tomen conciencia de que existen herramientas jurídicas que las respaldan por ser mujeres. El presente trabajo se realizó en las 16 delegaciones ahora alcaldías, el primer año fueron 8 sedes con 10 talleres de diversos temas como derechos humanos, de la mujer, sobre su cuerpo, derechos económicos, principalmente, el segundo año fueron 10 sedes con 10 talleres se actualizaron las pláticas sobre derechos humanos, de mujeres, se agrego comunicación digital y la relación equidad de género y medio ambiente, para el último año se compactaron a 8 sedes con 8 diferentes talleres teniendo la base los derechos humanos y de la mujer. Se obtuvo que el primer año asistieron aproximadamente 150 participantes capacitándose por mes en cada cede un total de 1,500 mujeres al año, en 2017 fueron 2,000 mujeres capacitas y en el 2018 fueron 2,580 capacitadas, observándose un aumento proporcional del interés de las mujeres por los diferentes talleres, las participantes fueron desde amas de casa, estudiantes y profesionistas, de 15 años y más

Enhancing the piston effect in underground railway tunnels

The air flows induced by train movement in tunnels can be used for the purposes of underground railway ventilation. The magnitude of such air flows depends strongly upon the blockage ratio (the ratio of the train and tunnel cross-sectional areas) of the train. This study investigates the impact on the generated air flows due to the alteration of the aerodynamic resistance of the train, as a means of varying the blockage ratio. The alteration in aerodynamic resistance was achieved by using an aerofoil at a variety of different angles of inclination. A two-dimensional computational fluid dynamics model of a train travelling through a tunnel was developed and validated using experimental data from literature. This model was then used to investigate the influence of an aerofoil upon the volume of displaced air and the effect upon the aerodynamic work done by the train (work done by the train due to air drag). The results of this study show that ventilating air flows can be increased by 3% using an aerofoil at a fixed angle of 10° without increasing aerodynamic work. Through using a combination of different angles during different phases of train motion, a maximum increase in air displacement of 8% can be achieved, while not increasing the aerodynamic work done by the train. This equates to the train generated air displacement delivering an extra View the MathML source of air supply during the period of train motion

Soil erosion processes in european vineyards: a qualitative comparison of rainfall simulation measurements in Germany, Spain and France

Small portable rainfall simulators are considered a useful tool to analyze soil erosion processes in cultivated lands. European research groups in Spain (Valencia, Málaga, Lleida, Madrid and La Rioja), France (Reims) and Germany (Trier) have used different rainfall simulators (varying in drop size distribution and fall velocities, kinetic energy, plot forms and sizes, and field of application) to study soil loss, surface flow, runoff and infiltration coefficients in different experimental plots (Valencia, Montes de Málaga, Penedès, Campo Real and La Rioja in Spain, Champagne in France and Mosel-Ruwer valley in Germany). The measurements and experiments developed by these research teams give an overview of the variety of methodologies used in rainfall simulations to study the problem of soil erosion and describe the erosion features in different climatic environments, management practices and soil types. The aims of this study are: (i) to investigate where, how and why researchers from different wine-growing regions applied rainfall simulations with successful results as a tool to measure soil erosion processes; (ii) to make a qualitative comparison about the general soil erosion processes in European terroirs; (iii) to demonstrate the importance of the development of standard method for measurement of soil erosion processes in vineyards, using rainfall simulators; and (iv) and to analyze the key factors that should be taken into account to carry out rainfall simulations. The rainfall simulations in all cases allowed infiltration capacity, susceptibility of the soil to detachment and generation of sediment loads to runoff to be determined. Despite using small plots, the experiments were useful to analyze the influence of soil cover to reduce soil erosion, to make comparisons between different locations, and to evaluate the influence of different soil characteristics. The comparative analysis of the studies performed in different study areas points out the need to define an operational methodology to carry out rainfall simulations, which allows us to obtain representative and comparable results and to avoid errors in the interpretation in order to achieve comparable information about runoff and soil los