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Sample records for bacterias anaerobias estudio

  1. Papel de las bacterias anaerobias en la etiopatogenia de la patología pulpoperiapical

    OpenAIRE

    Pumarola Suñé, José; Brau Aguadé, Esteban; Canalda Sahli, Carlos

    1993-01-01

    La mayor prevalencia de especies microbianas estrictamente anaerobias en las lesiones periapicales, particularmente Bacteroides pigmentados, y las recientes taxonomías aprobadas para determinadas especies de este grupo bacteriano ha motivado la revisión de la relevancia que tienen estos microorganismos en la etiopatogenia pulpoperiapical.

  2. INFECCIONES POR BACTERIAS ANAEROBIAS: CRITERIOS DE MANEJO CLÍNICO Y PROCEDIMIENTOS MICROBIOLÓGICOS DE DIAGNÓSTICO

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    Luz Angélica Quintero B.

    2009-06-01

    Full Text Available El incremento de las infecciones por bacterias anaerobias, la resistencia de estos gérmenes a las limitadas opciones terapéuticas de uso empírico, el poco y reciente conocimiento que se tiene sobre estos gérmenes, conlleva a que el clínico no sospeche en la mayoría de los casos que se encuentra ante un posible cuadro infeccioso cuyo agente etiológico involucra un germen anaerobio, retardando el diagnostico oportuno y el inicio adecuado de la antibioticoterapia, explicando el súbito aumento en la morbi-mortalidad y en la vulnerabilidad de los pacientes. Esto crea la apremiante necesidad en las instituciones hospitalarias de desarrollar protocolos y estandarizar guías de manejo de infecciones por bacterias anaerobias actualizados y acordes a los recursos disponibles que garanticen y optimicen los procesos que intervienen en la búsqueda y recuperación de estos gérmenes tan exigentes, y que lepermitan a todo el cuerpo médico y paramédico un adecuado manejo de estos eventos para el mejoramiento de la atención y seguridad del los pacientes. El propósito de esta guía es estandarizar un protocolo actualizado en diagnostico clínico y bacteriología anaeróbica que unifique criteriosentorno a la selección, toma y transporte adecuados de muestras clínicas, el cual garantice la viabilidad del espécimen y la recuperación de gérmenes anaerobios con el fin de obtener su identificación y susceptibilidad antibiótica.

  3. Estudio cinético del proceso de digestión anaerobia de las aguas residuales de la elaboración de aceitunas de mesa negras

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    Borja Padilla, R.

    1992-12-01

    Full Text Available A kinetic study of the anaerobic digestion process of wastewaters from black olive preparation was carried out. The bioreactors used accommodated various suspended micronized clay supports of different chemical composition (Sepiolite and Bentonite. Assuming that the overall anaerobic digestion process conforms to a first-order kinetics, experimental data pairs, namely the methane volume yielded (G and the time (t fitted the equation: G=Gm·[1-exp (-Ko·t], the rate coefficient, Ko, was determined in each of the situations studied. The support used has a marked influence on the kinetic constant of the process; the Sepiolite support yields significantly the highest values. The average Ko values, obtained in the rank of COD between 0 and 1 g/L were: 1,83 days-1 (Sepiolite and 1,23 days-1 (Bentonite. For values of COD greater than 1g/L, the specific rate constant decreased when the volume of wastewater added or substrate concentration was increased. The yield coefficients of methane, Yp/s, were 333 and 316 mL CH4/g COD for the Sepiolite and Bentonite reactor, respectively. Treatment yields of COD were above 95% in all the cases.

    Se ha efectuado un estudio cinético del proceso de digestión anaerobia de las aguas residuales obtenidas en la elaboración de aceitunas negras, mediante biorreactores que contienen en suspensión soportes micronizados de tipo arcilloso de distinta composición química (Sepiolita y Bentonita. Admitiendo que globalmente el proceso de digestión anaerobia sigue una cinética de primer orden, se ajustan las parejas de datos experimentales, volumen de metano acumulado (G, tiempo (t a la ecuación: G=Gm·[1-exp (-Ko·t], determinándose los valores del coeficiente de velocidad Ko, para cada caso estudiado. El soporte utilizado ejerce una influencia acusada sobre la constante cinética del proceso

  4. Estudio de las condiciones de operación para la digestión anaerobia de residuos sólidos urbanos

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    Castillo M. Édgar Femando

    2003-12-01

    Full Text Available En este trabajo se estudia la digestión anaerobia como una opción tecnológica para el tratamiento de la fracción orgánica de los residuos sólidos urbanos de la ciudad de Bucaramanga (Santander, Colombia. Inicialmente se realizó la escogencia del inoculo a emplear, por medio de la evaluación del comportamiento de tres tipos de lodo anaerobio: uno proveniente del reactor UASB No. 2 de la Planta de Tratamiento de Aguas Residuales de Río Frío (Municipio de Girón, Santander, denominado [PTAR]; otro proveniente de un biodigestor anaerobio alimentado con estiércol de porcinos (Mesa de Los Santos, Santander, denominado [PIG] y una mezcla 1:1 (v/v de los dos lodos anteriores, llamado [MDC]. Se evaluó el comportamiento de estos lodos en reactores de 500 ml a tempe­raturas mesofílicas y termofílicas, y se obtuvo un mejor comportamiento para el lodo [MIX]. Posteriormente se realizó el estudio de tres tiempos de retención hidráulicos en un reactor de 201 de capacidad total con un volu­men de trabajo de 13 1. Del estudio se concluyó que incrementos de 10 a 15 °C en la operación del reactor triplican la producción de metano, y que además el tiempo de retención hidráulico influye notoriamente en la producción específica de metano obteniéndose mejores conversiones a mayores tiempos (25 días, lo que a su vez afecta la remoción de carga orgánica en el sistema. Otra variable importante en la operación del biodigestor es la agitación, la cual debe realizarse discontinuamente pues disminuye la actividad biológica en la metanización.

  5. Estudio de las condiciones de operación para la digestión anaerobia de residuos sólidos urbanos

    OpenAIRE

    Castillo M. Édgar Femando; Cristancho Diego Edison; Arellano A. Víctor

    2007-01-01

    En este trabajo se estudia la digestión anaerobia como una opción tecnológica para el tratamiento de la fracción orgánica de los residuos sólidos urbanos de la ciudad de Bucaramanga (Santander, Colombia). Inicialmente se realizó la escogencia del inoculo a emplear, por medio de la evaluación del comportamiento de tres tipos de lodo anaerobio: uno proveniente del reactor UASB No. 2 de la Planta de Tratamiento de Aguas Residuales de Río Frío (Municipio de Girón, Santander), denominado [PTAR]; o...

  6. Estudio de viabilidad económica de una unidad de digestión anaerobia de residuos de una empresa de productos lácteos

    OpenAIRE

    Cuasnicú Sáenz, Laila

    2014-01-01

    El proyecto consiste en estudiar la viabilidad económica de implantar una unidad de digestión anaerobia alimentada con residuos resultantes de la actividad de producción de una empresa elaboradora de productos lácteos, siendo estos residuos productos fabricados no comercializables y fangos procedentes de un proceso de tratamiento de aguas residuales. Se estudia la gestión actual de dichos residuos en el territorio español y se proponen tres posibles variantes, diferenciándose entre sí por ...

  7. Estudio cinegético de la digestión anaerobia de alpechín, procedente de la extracción de aceite utilizando olivex, previamente biotratado con Geotrichum Candidum

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    González Becerra, A.

    1992-08-01

    Full Text Available A kinetic study of the anaerobic digestion of olive mill wastewater (OMW which was obtained with the technological helper "Olivex", was carried out. An identical wastewater, obtained without this enzyme was also used. Both OMW were pre-treated aerobically with Geotrichum Candidum to eliminate the greater part of the phenolic compounds responsible for inhibition. The anaerobic process was carried out in bioreactors with microorganisms immobilized on two micronized clay supports, Sepiolite and Bentonite. Assuming that the overall anaerobic digestion process conforms to a first-order kinetic, specific rate constants, Ko, were obtained by using the Roediger's equation in each case. In contrast to what takes place with both OMW without pretreatment, kinetic constant was observed virtually constant when the substrate concentration was increased, in the range of COD (chemical oxygen demand studied. The mean value of this kinetic parameter was a 40% larger for the OMW obtained with Olivex compared to the reference OMW, in the two digesters used. Sepiolite favoured the kinetic and increased the yield coefficient compared to Bentonite.Se ha efectuado un estudio cinético del proceso de digestión anaerobia de un alpechín obtenido con el coadyuvante tecnológico "Olivex" en comparación con un testigo obtenido sin este enzima, que previamente han sido tratados de forma aerobia con Geotrichum Candidum para eliminar la mayor parte de los compuestos fenólicos responsables de su poder inhibidor. El proceso anaerobio se ha realizado en biorreactores con microorganismos inmovilizados en dos soportes micronizados arcillosos, Sepiolita y Bentonita. Admitiendo que globalmente el proceso de digestión anaerobia sigue una cinética de primer orden, se obtienen las constantes específicas de velocidad, Ko, para cada caso estudiado usando la ecuación de Roediger. A diferencia de lo que ocurre con ambos alpechines sin pretratar, la constante cinética se mantiene pr

  8. Estudio Comparativo del Pretratamiento Químico para mejorar La Digestión Anaerobia de Residuos Sólidos

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    Matilde López Torres

    2005-01-01

    Full Text Available Anualmente se producen millones de toneladas de residuos sólidos en todo el mundo, recibiendo solo una pequeña parte de este algún tipo de tratamiento. El resto, en vez de pensarse en soluciones que cierren el ciclo de vida que los devuelvan a la tierra, se destinan de forma indiscriminada a contaminar el entorno. La complejidad de estos residuos impone el estudio de métodos alternativos que contribuyan a mejorar la eficiencia del proceso de estabilización, reconociéndose que el paso limitante es la etapa de hidrólisis y solubilización del material orgánico complejo. La hidrólisis de las macromoléculas que componen los diferentes residuos sólidos, puede ser llevada a acabo por métodos químicos, físicos y biológicos, teniendo todos como objetivo el desdoblamiento de las moléculas complejas en unidades monoméricas más simples. Tales macromoléculas son insolubles, pudiendo ser transformadas en compuestos solubles que resultan más fácilmente asimilables a la hora de su biotransformación en etapas subsiguientes. El estudio del pretratamiento químico fue llevado a cabo teniendo en cuenta la naturaleza de tres de estos residuos complejos: los lodos procedentes de plantas depuradoras, la cachaza residuos sólidos procedente del proceso de fabricación de azúcar y la fracción orgánica de los residuos sólidos urbanos. En todos los casos se empleo Ca(OH2 como agente químico. El porcentaje de solubilización fue evaluado, en base a la cantidad de materia orgánica solubilizada, expresado en función de demanda química de oxígenos (DQO. A través del presente estudio se llegó a obtener un modelo que expresar el comportamiento de la solubilización en función del tiempo de solubilización y la concentración de álcalis.

  9. Estudio cinético del proceso de digestión anaerobia de aguas de lavado de aceitunas de almazara en reactores de mezcla completa con microorganismos inmovilizados

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    Borja, Rafael

    1999-04-01

    Full Text Available A kinetic study of the continuous anaerobic digestion process of wastewaters from the washing of olives prior to the oil production process was carried out in a completely mixed reactor with sepiolite immobilised biomass at 35° C. Four influent COD concentrations, 4,5, 3,5, 2,5 y 1,5 g COD/I were used as substrate operating for a hydraulic retention time range of 4,5 to 1,25 days. The Michaelis-Menten model has been applied, obtaining the values of the maximum substrate utilization rate, k( (g COD/g VSS day, and the kinetic constant of the process, Ks (g COD/I, for each influent substrate concentration studied. The values of these parameters significantly decreased with decreasing concentration of influent wastewater, showing the highest values for the greatest influent substrate concentration used as feed. The microbial yield coefficient, Yx, and sludge decay rate coefficient, kd, were also determined to be 0,14 g VSS/g COD and 0,003 days-1 respectively.

    Se ha efectuado un estudio cinético del proceso de digestión anaerobia en régimen continuo de aguas de lavado de aceitunas de almazara en un reactor de mezcla completa utilizando sepiolita como soporte para la inmovilización de los microorganismos responsables del proceso, a la temperatura de 35° C. Se utilizan cuatro concentraciones de sustrato como alimento, 4,5, 3,5, 2,5 y 1,5g DQO/I, operando con cada una de ellas en un rango de tiempos de retención hidráulicos de 4,5 a 1,25 días. Para ello, se aplica el método cinético de Michaelis-Menten, obteniéndose los valores de la velocidad máxima de utilización de sustrato, k(g DQO/g SSV día, y de la constante cinética del proceso, Ks (g DQO/I, para cada concentración de sustrato objeto de estudio. Se observa que estas constantes cinéticas disminuyen de forma significativa al disminuir la concentración de sustrato en el alimento

  10. Estudio de la digestión anaerobia en dos fases para el tratamiento de las aguas residuales de despulpe del beneficiado húmedo del café

    OpenAIRE

    Guardia Puebla, Yans

    2012-01-01

    Debido al aumento de los estándares de calidad exigidos internacionalmente, así como por una mayor presión sobre la industria mediante legislaciones ambientales más rigurosas, el sector cafetalero está obligado a buscar, a través de la investigación, un sistema adecuado de tratamiento para las aguas residuales generadas en el beneficiado húmedo del café. En este trabajo se evaluó el funcionamiento de la digestión anaerobia para el tratamiento de las aguas residuales de despulpe. Para ello, se...

  11. Biodegradación anaerobia de las aguas generadas en el despulpado del café

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    Jorge del Real Olvera

    2010-10-01

    Full Text Available Título en inglés: Anaerobic biodegradation of wastewater generated in the pulping of coffee Resumen El cultivo y procesado del café es una de las actividades agroindustriales más importantes en varios países de Latinoamérica; sin embargo, dicha actividad conlleva grandes impactos ambientales, ya que genera aguas residuales con alta carga contaminante. La peligrosidad ecológica de estos vertidos ha potenciado la búsqueda de alternativas para su tratamiento y disposición final. En este trabajo se empleó una comunidad microbiana proveniente del fluido ruminal vacuno, para investigar la factibilidad de su empleo en la depuración de aguas residuales provenientes del despulpado del café, mediante la disminución de la carga orgánica expresada como DQO, además del volumen de metano generado. La cinética de degradación fue seguida en un reactor por lotes, anaerobio y mesofílico de dos litros de capacidad, bajo diferentes condiciones de temperatura (28 y 36 ºC y pH (4,6; 7 y 8,5. Los resultados mostraron un índice volumétrico de lodos de 0,44 mL/g y actividad metanogénica específica de 0,0076 gDQO/gSST*d. En la mayoría de los casos, los resultados de remoción de DQO fueron superiores a la mitad del contenido orgánico inicial, llegando a 91,2% con pH de 4,6 y 28 ºC en 16 días. Los resultados muestran que el consorcio bajo estudio es capaz de adaptarse al sustrato y degradar la mayor parte de su carga orgánica, lo cual lo convierte en una interesante opción biotecnológica para el tratamiento de vertidos del despulpado de café. Palabras clave: biorremediación; bacterias metanogénicas; digestión anaerobia; biogás. Abstract The cultivation and processed of coffee, is one of the agro-industrial activities more important in several countries in Latin America; however this activity involves high environmental impacts, because generate wastewater with high pollution load. The danger ecological these discharges, has maximized the

  12. Contribución al estudio de las bacterias halofílicas en el mar ecuatoriano

    OpenAIRE

    Villamar, F.

    1987-01-01

    Durante los meses de marzo y abril de 1976, se realizó el estudio de las bacterias marinas en el mar ecuatoriano, las cuales sobrepasan densidades de 10 Bact./ml en el área océanica. Al mismo tiempo frente a las costas del Ecuador disminuyen estos valores entre 500 y 2.500 Bact./ml., excepto en el área del Golfo de Guayaquil, donde se encontró bacterias de origen continental en un gran parche de 106 bact./ml. de acuerdo al diagnóstico bioquímico diferencial, se trata de Bacilos Grammegativos ...

  13. Estudio de micoplasmas y bacterias aerobias en la vagina craneal de hembras caninas clínicamente sanas

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    Stornelli, María Alejandra; Cerdá, Raúl Oscar; Gobello, Cristina; Arauz, María Sandra; Stanchi, Néstor Oscar

    2000-01-01

    La flora bacteriana presente en la vagina de hembras caninas posee un discutido rol en las enfermedades reproductivas de esta especie, por lo tanto y para contribuir al esclarecimiento de este aspecto, se realizó un estudio de los microorganismos vaginales en 33 perras sanas. Las muestras fueron tomadas mediante hisopo cubierto y procesadas siguiendo las marchas bacteriológicas indicadas para bacterias aerobias y Micoplasmas. Se aislaron microorganismos a partir de 30 muestras, siendo 3 negat...

  14. Anaerobia Treatments of the domestic residual waters. Limitations potentialities

    International Nuclear Information System (INIS)

    The quick growth of the Latin American cities has prevented that an appropriate covering of public services is achieved for the whole population, One of the undesirable consequences of this situation is the indiscriminate discharge from the domestic and industrial residual waters to the nearest bodies of water with its consequent deterioration and with disastrous consequences about the ecology and the public health. The developed countries have controlled this situation using systems of purification of the residual waters previously to their discharge in the receptor source. The same as the technology of the evacuation of the served waters, they have become numerous efforts for the application of the purification systems used in the countries developed to the socioeconomic, climatic and cultural conditions of our means. One of the results obtained in these efforts is the economic inability of the municipalities to pay the high investment costs and of operation of the traditional systems for the treatment of the residual waters. Contrary to another type of public services, the treatment of the residual waters needs of appropriate technological solutions for the Climatic and socioeconomic means of the developing countries, One of the technological alternatives for the purification of the residual waters that has had a great development in the last decades has been that of the biological treatments in t anaerobia ambient. The objective of this contribution is to present, to author's trial, the limitations and potentialities of this technology type with special emphasis in the case of the domestic residual waters

  15. Estudio técnico-económico de la digestión anaerobia conjunta de la fracción orgánica de los residuos sólidos urbanos y lodos de depuradora para la obtención de biogás

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    Montes Carmona, María Estela

    2008-01-01

    En este trabajo de investigación se realizan dos estudios técnicos, el primero de ellos compara el rendimiento en función de ST, STV y DQO, y la producción y riqueza de biogás de tres digestores en monoetapa usando 3 sustratos diferentes (fango, foRSU y codigestión de fango-foRSU), así como un breve análisis económico a partir de valores obtenidos respecto a la producción y riqueza del biogás. El segundo estudio, compara las tecnologías de digestión en fases y monoetapa, utilizando como sustr...

  16. Estudio sobre el comportamiento de bacterias patógenas entéricas vehiculadas por alimentos

    OpenAIRE

    Fernández Escudero, Irene

    2015-01-01

    En Microbiología de los Alimentos destacan dos campos de interés: la protección de los consumidores frente a enfermedades transmitidas por alimentos y la prevención de alteraciones de los productos por estos agentes. La familia Enterobacteriaceae constituye uno de los principales ejemplos de bacterias vehiculadas por alimentos, de la que forman parte las especies Escherichia coli y Cronobacter sakazakii. La creación de modelos predictivos y el estudio de su comportamiento constituyen herramie...

  17. Caracterización y digestión anaerobia de las aguas de lavado del aceite de oliva virgen

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    Borja, R.

    1993-04-01

    Full Text Available A characterization and kinetic study of the anaerobic digestion of waters from washing of virgin olive oil were carried out. The experimental setup used consisted of a 1;litre thorough mixing bioreactor that was operated at 35 °C and loaded with sepiolite-immobilized biomass at a concentration of 10.8 g VSS/L. The bioreactor worked satisfactorily for a hydraulic retention time of 1.1 to 5.0 days and eliminated more than 92% of the initial COD in all instances. Guiot's kinetic model was used to determine the macroenergetic parameters of the system, which was found to have a true yield coefficient for the biomass Y = 0.006 g VSS/g COD and a specific rate of substrate uptake for cell maintenance m = 0.072 g COD/g VSS ∙ day. According to the experimental results obtained, the rate of substrate uptake, Rs (g COD/g VSS ∙ day, was correlated with the concentration of biodegradable substrate, Sb (g COD/L, through an equation of the Michaelis-Menten type.

    Se ha efectuado la caracterización y un estudio cinético del proceso de digestión anaerobia de las aguas residuales obtenidas en el lavado del aceite de oliva virgen. El equipo experimental consta de un biorreactor de mezcla completa de 1 litro de volumen y opera a 35 °C con una concentración de biomasa de 10.8 g SSV/L inmovilizada sobre sepiolita. El biorreactor opera de modo satisfactorio en un rango de 5.0 a 1.1 días de tiempo de retención hidráulico, eliminando en todos los casos más del 92% de la DQO inicial. Se comprueba el modelo cinético propuesto por Guiot y con el auxilio del mismo se determinan los parámetros macroenergéticos de este sistema: Y = 0.006 (g SSV/g DQO, coeficientes de rendimiento verdadero para la biomasa y m = 0.072 (g DQO/g SSV ∙ día, velocidad específica de consumo de sustrato para el mantenimiento celular. Los datos experimentales obtenidos indican que la velocidad de consumo de sustrato Rs (g DQO/día ∙ g SSV se correlaciona con la

  18. Estudio y determinación de la población de bacterias en vino mediante epifluorescencia

    OpenAIRE

    Curiel Llanos, Laura

    2014-01-01

    Se ha procedido a la determinación de la población de bacterias mediante técnicas de epifluorescencia para tener un conocimiento más amplio y preciso de las bacterias viables y no viables en los procesos de elaboración de vinos. Dichas determinaciones son fundamentales a efectos de la calidad en la elaboración del vino. Se realiza la comparación con otras técnicas microbiológicas actualmente utilizadas.

  19. Bacteremia due to anaerobic bacteria: epidemiology in a northern Bari Hospital, Italy

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    Maria Antonietta Distasi

    2015-06-01

    Full Text Available Background. Anaerobic bacteria are part of the commensal bacterial flora of skin and mucosae. Iatrogenic and pathological conditions altering this commensal relationship cause life-threatening diseases. Materials and Methods. We analysed the blood cultures sent to the microbiology of our hospital between 2008 and the first quarter of 2013 to measure the frequency of bacteraemia caused by anaerobia. We examined 3138 vials of blood cultures for anaerobia, inoculated following in-house standard procedures. The colonies grown in absence of air were subjected to biochemical analysis. The MICs of metronidazole for 23 of the 26 organisms was tested. Results. Twelve bacteria of the Bacteroides genus were identified, 9 Propionibacterium acnes, 1 Peptosctreptococcus micros, 1 Lactobacillus acidophilus, 1 Clostridium perfringens, 1 Prevotella oralis, 1 Eubacterium lentum. Conclusions. The analysis of the results suggests that the incidence of cultures positive to anaerobia was constant across the years. We note that advanced age, altered mucocutaneous tropism, alterations to the oral and intestinal bacterial flora intensify the risk of anaerobial pathogenicity. The analysis of the metronidazole-determined MIC suggests that the intestinal anaerobic flora responds well to therapy and prophylaxis with Metronidazole, while the anaerobic bacteria residing on skin and other mucosae are resistant. It is however hard to determine the clinical impact of anaerobic bacteremiae and their effect on the outcome of the patient, due to the scarcity of available clinical data.

  20. Panorama del tratamiento de aguas residuales con tecnología anaerobia en la Costa Atlántica Colombiana

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    Vásquez Núñez, Geinny Del Carmen Elena

    2015-01-01

    El presente trabajo busca identificar las plantas de tratamiento de aguas residuales con tecnología anaerobia existentes en la Costa Caribe y el potencial de aplicación de dicha tecnología en esa región del país. Se estableció que el número de instalaciones con sistemas anaerobios es bastante reducido en comparación con otras soluciones, pero existe un alto potencial de aplicación, especialmente en lo que se refiere a reactores tipo UASB, los cuales se han posicionado sólidamente en instalaci...

  1. SITUACIÓN ACTUAL Y PERSPECTIVA DE LAS RELACIONES ENDÓFITAS PLANTA-BACTERIA. ESTUDIO DE CASO Gluconacetobacter diazotrophicus-CULTIVOS DE IMPORTANCIA ECONÓMICA

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    B. Dibut

    2009-01-01

    Full Text Available En los últimos años, ha ganado especial interés el estudio de las asociaciones endofíticas planta-microoganismos, con énfasis en la introducción en la práctica agrícola de los buenos resultados que se han obtenido en la agrobiología. En este trabajo se ofrece una panorámica de la situación actual y perspectiva de estas asociaciones ilustradas en gran medida por las interacciones Rhizobium-cereales, Azorhizobium-arroz, Azospirillum y Herbaspirillum, al igual que cereales y Gluconacetobacter diazotrophicus con diferentes cultivos. Se plantea un proceso de rotación microbiana que manifiesta la bacteria Rhizobium en las diferentes fases de asociación cíclica en el agroecosistema (leguminosa, nódulo-suelo-gramínea-suelo-leguminosa en función de la fisiología de la productividad y el rendimiento. En el estudio con G. diazotrophicus, en las determinaciones realizadas en viandas tropicales y frutales en las condiciones de Cuba, se encontró una concentración de células de 4.2x105 por gramo de tejido fresco en las plantas bacterizadas y 2.7x102 células por gramo de tejido fresco para las hojas de plantas controles (sin bacterizar; por eso, es necesario aumentar la concentración bacteriana, tanto en las condiciones experimentales como de extensión, para obtener una respuesta favorable del efecto agrobiológico sobre las especies antes relacionadas. La respuesta a la inoculación encontrada para yuca, malanga y papaya constituyen un primer informe mundial. El impacto económico como consecuencia de la inoculación es elevado, con una relación beneficio/ costo superior a 40:1, por lo que resulta una biotecnología sumamente atractiva para ser introducida en el mercado actual de agrobiológicos. Igualmente, el resultado presenta impacto científico, tecnológico, ambiental y social.

  2. Caracterización microbiológica y molecular de la comunidad anaerobia durante la co-fermentacion de residuos agropecuarios con adición de arcillas para la obtención de metano

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    Janet Jiménez-Hernández

    2014-01-01

    Full Text Available En la fermentación anaerobia de residuos agropecuarios para la obtención de metano influyen de manera determinante las condiciones nutricionales para el establecimiento y desarrollo de la microbiota. Por tal razón, el objetivo de este trabajo fue analizar el efecto de la co-fermentación anaerobia de estiércol y paja residual agrícola con adición de arcillas sobre la diversidad de la comunidad microbiana que se establece a diferentes temperaturas. Para ello se desarrollaron cultivos en régimen batch, a 35 y 55 ºC y se analizó la actividad metanogénica y no metanogénica, el crecimiento microbiano en medios con sustratos diferenciales (metanol, acetato y formato/H2-CO2 y mediante métodos moleculares como el polimorfismo de longitud de fragmentos de restricción terminales (T-RFLP. Las actividades enzimáticas hidrolíticas, glucolíticas y metanogénicas revelaron el predominio de poblaciones específicas en las condiciones de adición de arcillas y temperatura experimentadas. Las actividad hidrolítica utilizando el sustrato celulosa mostró que en condiciones termofílicas se favoren las poblaciones de bacterias celulolíticas termófilas. Las actividades hidrolíticas y glucolíticas fueron diferentes en ambas temperaturas. El crecimiento diferencial y el análisis de T-RFLP demostraron el efecto de la co-fermentación de estiércol y paja con adición de arcillas sobre la diversidad microbiana que se establece a las dos temperaturas. Ambos ensayos sugirieron el predominio de las metanógenas acetotróficas del orden de Methanosarcinales (géneros Metanosarcinas y Metanosaetas a 35 ºC, mientras que a 55 ºC se constató un predominio de metanógenas hidrogenotróficas de los órdenes Methanomicrobiales y Methanobacteriales.

  3. Caracterización de la digestión anaerobia de proteínas de origen animal

    OpenAIRE

    Flotats Ripoll, Xavier; Fernández García, Belén; Palatsi Civit, Jordi

    2010-01-01

    El objetivo del presente trabajo es estudiar la cinética de la descomposición anaerobia de la fracción proteica de residuos de la industria cárnica, adoptando como proteínas modelo la gelatina y las harinas de carne, y como modelo matemático de referencia el ADM1. Para la identificación práctica de parámetros cinéticos se han diseñado y ejecutado experimentos discontinuos simultáneos (EDS). Los resultados obtenidos de la constante de hidrólisis para las dos proteínas estudiadas son simi...

  4. Estudio bioquímico y molecular de la producción de precursores de carbamato de etilo por bacteria lácticas asociadas al proceso de vinificación

    OpenAIRE

    Araque Granados, Maria Isabel

    2010-01-01

    Las bacterias lácticas (BL) mas frecuentes aisladas de vino fueron estudiadas en su capacidad de degradación de la arginina y su implicación en la generación de precursores de carbamato de etilo (CE) como citrulina y carbamil fosfato. Todos los lactobacilos heterofermentativos así como Oenococcus oeni, Pediococcus pentosaceus y algunas cepas de Leuconostoc mesenteroides y Lactobacillus plantarum fueron positivas en cuanto a su capacidad de degradación. Así mismo también se estudio la presenci...

  5. Digestión anaerobia de las aguas de lavado de aceitunas de almazara: Influencia del período de recolección sobre la cinética del proceso

    Directory of Open Access Journals (Sweden)

    Borja-Padilla, R.

    1994-06-01

    Full Text Available A kinetic study was carried out of anaerobic digestion of waste waters after washing olives used for oil production, collected at three different harvest times (December 1992, January and February 1993. A 1-litre mixed batch bioreactor operated at 35°C and containing a sepioliteimmobilized biomass was used.
    Assuming that the overall anaerobic digestion process conforms to a first-order kinetics, experimental data pairs, namely methane volume yield (G and time (t, fit Roediger's equation, from which the rate coefficient values, K0, were determined in each of the situations studied. The rate coefficient considerably decreased with the han/est time, over the substrate concentration range studied (0.5-2.5 g COD/l. The average values obtained were: 1.67,1.13 and 0.75 days-1 for the waste waters corresponding to the three harvest times considered. Also, the methanogenic activity decreased with the ripening of the olives; the observed differences increased when the substrate concentration in the digester increased.
    The coefficients of methane yield, Yp, ranged between 0.263 (first harvest time and 0.298 l CH4/g COD removed (third harvest time. The elimination of COD exceeded 64% in all cases.

    Se ha efectuado un estudio cinético del proceso de digestión anaerobia de aguas de lavado de aceitunas de almazara, obtenidas en tres épocas diferentes de la campaña oleícola (Diciembre de 1992, Enero y Febrero de 1993. El proceso se ha realizado en un reactor discontinuo con agitación de 1 litro de volumen, con biomasa inmovilizada sobre sepiolita, a la temperatura de 35°C.
    Admitiendo que globalmente el proceso de digestión anaerobia sigue una cinética de primer orden, se ajustan las parejas de datos experimentales, volumen de metano acumulado (G-tiempo (t a la ecuación de Roediger, determinándose los valores del coeficiente de velocidad, K0, para cada caso estudiado. Dentro del

  6. Aplicaci??n de fluorocromos para el estudio de la viabilidad de las Bacterias ??cido L??cticas (BAL) presentes en productos l??cteos

    OpenAIRE

    MORENO Y.; Hern??ndez, M.; Collado, M. C.; Herna??ndez, E.

    2000-01-01

    Se estudi?? la viabilidad de las Bacterias ??cido L??cticas (BAL) procedentes de diversas leches fermentadas de origen comercial, almacenadas en refrigeraci??n a 4??C. Las bacterias viables y cultivables fueron enumeradas en los medios TPY (Bifidobacterias), MRS (Lactobacilos) y M17 (Estreptococos). Los recuentos totales (viables y muertas) se llevaron a cabo mediante el uso del sistema comercial LIVE/DEAD?? Bac LightTM VIABILITY. La viabilidad de las BAL fue estudiada antes y des...

  7. SITUACIÓN ACTUAL Y PERSPECTIVA DE LAS RELACIONES ENDÓFITAS PLANTA-BACTERIA. ESTUDIO DE CASO Gluconacetobacter diazotrophicus-CULTIVOS DE IMPORTANCIA ECONÓMICA

    OpenAIRE

    B. Dibut; R. Martínez-Viera; Marisel Ortega; Yoania Ríos; Grisel Tejeda; Liuba Planas; Janet Rodríguez

    2009-01-01

    En los últimos años, ha ganado especial interés el estudio de las asociaciones endofíticas planta-microoganismos, con énfasis en la introducción en la práctica agrícola de los buenos resultados que se han obtenido en la agrobiología. En este trabajo se ofrece una panorámica de la situación actual y perspectiva de estas asociaciones ilustradas en gran medida por las interacciones Rhizobium-cereales, Azorhizobium-arroz, Azospirillum y Herbaspirillum, al igual que cereales y Gluconacetobacter di...

  8. Influencia de los coadyuvantes tecnológicos utilizados en el proceso de elaboración de aceite de oliva sobre la cinética del proceso de digestión anaerobia del alpechín

    Directory of Open Access Journals (Sweden)

    Borja Padilla, R.

    1992-08-01

    Full Text Available A kinetic study of the anaerobic digestion of olive mill wastewater, which was obtained with the technological helper "Olivex" (Carbohydrase -pectinases, cellulases and hemicellulases- from the Aspergillus aculeatus was carried out. An identical wastewater, obtained without this enzymatic formulation was also used. The process was carried out in bioreactors with microorganisms immobilized on two micronized clay supports, Sepiolite and Bentonite. The methane volume-time data pairs obtained were used to calculate the specific rate constant, Ko, by using the Roediger's equation. A decrease of the specific rate constant value was observed over the substrate concentration studied when the volume of wastewater added was increased; this confirmed the occurrence of an inhibition process, which was more marked for the olive mill wastewater obtained with Olivex. The Levenspiel's model was used to obtain the inhibition constants of this process.

    Se ha efectuado un estudio cinético del proceso de digestión anaerobia de un alpechín obtenido con el coadyuvante tecnológico "Olivex" (Carbohidrasa -pectinasas, celulasas y hemicelulasas- procedente de Aspergillus aculeatus en comparación con un testigo obtenido sin esta formulación enzimática. El proceso se ha realizado en biorreactores con microorganismos inmovilizados en dos soportes micronizados arcillosos, Sepiolita y Bentonita. A partir de los datos volumen de metano-tiempo, se calculan las constantes específicas de velocidad, Ko, utilizando la ecuación de Roediger. Dentro del rango de concentración de sustrato estudiado se observa una disminución de la constante cinética al aumentar el volumen de residuo añadido a los digestores lo que confirma la existencia de un proceso de inhibición, que es más acusado en el caso del alpechín obtenido con Olivex. Para determinar las constantes de inhibición del proceso se utiliza el modelo propuesto por Levenspiel.

  9. Técnicas moleculares aplicadas a la caracterización y estudio de la supervivencia de bacterias lácticas del yogur

    OpenAIRE

    García Hernández, Jorge.

    2011-01-01

    Para que los microorganismos probióticos ejerzan su efecto beneficioso sobre el huésped, han de encontrarse en proporciones elevadas en el producto y ser capaces de sobrevivir en suficiente cantidad al tránsito gastrointestinal. Se ha producido una cierta discrepancia entre diferentes líneas de investigación a la hora de afirmar los efectos beneficiosos del yogur tradicional. Algunas de ellas aseguran que sus bacterias no son capaces de sobrevivir al tracto gastrointestinal mientras que otras...

  10. Estudio de las propiedades tecnológicas de bacterias aisladas de leche materna: aplicación para el desarrollo de alimentos funcionales

    OpenAIRE

    Cárdenas Cárdenas, Nivia

    2015-01-01

    Las bacterias lácticas BAL tienen una gran importancia económica por ser las más usadas en la producción de productos lácteos. La rápida producción de ácidos orgánicos el consumo de nutrientes presentes en la leche y/o la producción de varios compuestos antimicrobianos controla el crecimiento de microorganismos alterantes. Además las BAL también contribuyen al desarrollo de aroma sabor y textura adecuados en el producto final. Por otra parte, muchas cepas de BAL y Bifidobacterium son bien con...

  11. Study of the phage production efficiency in the bacteria lysis processes; Estudio del rendimiento en fagos para los procesos de lisis bacteriana

    Energy Technology Data Exchange (ETDEWEB)

    Vidania Munoz, R. de; Garces, F.; Davila, C. A.

    1979-07-01

    In this work we present a search for the best production conditions of {lambda}vir and{lambda} clear phages In E coli K12 and E coli C{sub 6}00 infected cells respectively. By keeping fixed some parameters of the process as the bacterial and phage generation times and the bacterial burst side, we have found that the lysis yield is strongly dependent on the multiplicity and in a lesser degree on the infection time. It appears from the experimental results that other variables are important, as infection efficiency and approach time from phages to bacteria. We will try to describe the lysis phenomenon by a numerical model on the bases of the se experimental results. (Author) 11 refs.

  12. Evaluación de diagramas de flujo de sistemas de tratamiento de deyecciones ganaderas que incluyan codigestión anaerobia

    OpenAIRE

    Pineda Castro, Carme

    2011-01-01

    El objetivo del presente trabajo ha sido la confección de una herramienta informática que permita evaluar, mediante balances de materia y energía, las diferentes combinaciones de procesos de tratamiento de deyecciones ganaderas conducentes a la producción de energía, mediante digestión o codigestión anaerobia, o a la obtención de productos que permitan una mejora en la gestión de los nutrientes, mediante la aplicación de sistemas de separación, concentración o eliminación biológica de nitróge...

  13. Estudio para la gestión de residuos ganaderos mediante digestión anaerobia en el polígono ganadero de Funes (Navarra)

    OpenAIRE

    García Pejenaute, Tamara

    2012-01-01

    Este Trabajo Final de Carrera tiene como objetivo fundamental lograr la gestión de los residuos ganaderos de las explotaciones agropecuarias que se encuentran emplazadas en el polígono ganadero del municipio de Funes (Navarra) mediante la implantación de una planta de biogás, como consecuencia directa o indirecta del modelo actual de ocupación y uso actual del territorio. Para ello, se intenta explorar las posibilidades energéticas de los residuos orgánicos correspondientes ...

  14. Influencia de la velocidad de carga orgánica sobre el proceso de digestión anaerobia de aguas de lavado de aceitunas de almazara en reactores de lecho fluidizado

    Directory of Open Access Journals (Sweden)

    Borja, Rafael

    1998-02-01

    Full Text Available A study of the anaerobic digestion process of wastewaters from the washing of olives prior to the oil production process was carried out in a fluidized bed reactor with sepiolite immobilised biomass at 35°G. The bioreactor worked satisfactorily using Influent COD concentrations of 4.5,3.5,2.5 and 1.5 g COD/I for a hydraulic retention time (HRT range of 4.5 to 1,25 days. COD removal efficiencies in the range 50-90% were achieved in the reactor, when evaluated at organic loading rates of between 0.46 and 2.25 g COD/I day using the highest influent substrate concentration (So = 4.5 g COD/I. COD and volatile fatty acid (VFA concentration were Increased In parallel with the increase of organic loading rate in the reactor, VFA concentration showing a maximum value of 1.55 g acetic acid/I at the most unfavourable case studied (So = 4,5 g COD/I and HRT = 1.25 days. The increase in effluent VFA concentrations was always counteracted by the high alkalinity values (3440-4670 mg CaCO3/l which brought about the high stability of the process and values of the alkalinity/VFA ratio lower than 0.3-0.5, except for the above-mentioned case, limit value over which the anaerobic process is destabilized. The yield coefficient of methane production was 0.281 methane STP/g COD removed.

    Se ha efectuado un estudio del proceso de digestión anaerobia en régimen continuo de aguas de lavado de aceitunas de almazara en un reactor de lecho fluidizado utilizando sepiolita como soporte de adhesión bacteriana a la temperatura de 35°C. El biorreactor operó de modo satisfactorio utilizando concentraciones de alimento de 4,5, 3,5, 2,5, y 1,5 g DQO/I en un rango de 4,5 a 1,25 días de tiempo de retención hidráulico (TRH. Se han obtenido porcentajes de eliminación de DQO entre el 50 y el 90% para velocidades de carga orgánica variables entre 0,46 y 2,25 g DQO/I día utilizando la concentración de alimento más elevada (S

  15. Mejora de la calidad de vinos de la variedad Albariño mediante crianza biológica anaerobia con la levadura ecotípica Saccharomyces cerevisae DSM 21378

    OpenAIRE

    Martínez Rodríguez, Adolfo José; Carrascosa, Alfonso V.; Juega, M.; Núñez, Y. P.; Rodriguez Canas, Emilio

    2010-01-01

    La presente invención se refiere al uso del microorganismo de la especie Saccharomyces cerevisae DSM 21378 o de una micropoblación que comprende dicho microorganismo, para la crianza biológica anaerobia de vino producido con uvas de la especie Vitis vinifera varo Albariño. Dicha cepa DSM 21378 o una población que la comprende, pueden usarse para el aumento de coloides glicoproteicos en dicho vino, donde preferiblemente dichos coloides glicoproteicos son manoproteína...

  16. Estudio seguridad bobinadora IHT

    OpenAIRE

    Odériz Santos, Carlos

    2011-01-01

    Este proyecto fin de carrera tiene como objetivo el estudio de seguridad y salud de una bobinadora de la empresa ValcoMelton. Con dicho estudio nos aseguraremos que la citada máquina cumpla el marcado CE.

  17. Utilización de las escorias de incineración de RSU para el incremento del poder calorífico del biogás generado por digestión anaerobia de la FORSU

    OpenAIRE

    Valle Zermeño, Ricardo del

    2013-01-01

    La utilización de las escorias provenientes de la incineración de residuos sólidos urbanos (RSU) para absorber CO2 y H2S del biogás obtenido por digestión anaerobia de la Fracción Orgánica de los RSU (FORSU) tiene un doble beneficio. Por un lado la optimización energética al incrementar el poder calorífico del gas y por otro la estabilización de las escorias para una posterior reutilización. Tanto la FORSU como las escorias forman parte de la gestión integral de los RSU en los denominados ...

  18. Methanotrophic bacteria.

    OpenAIRE

    Hanson, R S; Hanson, T. E.

    1996-01-01

    Methane-utilizing bacteria (methanotrophs) are a diverse group of gram-negative bacteria that are related to other members of the Proteobacteria. These bacteria are classified into three groups based on the pathways used for assimilation of formaldehyde, the major source of cell carbon, and other physiological and morphological features. The type I and type X methanotrophs are found within the gamma subdivision of the Proteobacteria and employ the ribulose monophosphate pathway for formaldehy...

  19. Estudio de la teoría de despolarización catódica con permeación de hidrógeno y la bacteria Desulfovibrio desulfuricans

    Directory of Open Access Journals (Sweden)

    Pérez, O.

    2003-12-01

    Full Text Available A Desulfovibrio desulfuricans ssp. desulfuricans (SRB was used to study the permeation of hydrogen, using a Devanaran and Stachurski cell and a palladium sheet. The aim was to evaluate cathodic depolarization as a Sulfate-Reducing Bacteria action mechanism in Microbiologically Induced Corrosion. The permeation tests were run with and without cathodic polarization, using a sterile deaerated culture medium inoculated with 10 % SRB concentrated at 108 cel/ml. The results indicate bacterial growth in the order of 109-1010 cel/ml after 18 h both in the polarized and non-polarized tests, indicating that SRB developed regardless of the surface polarized as a source of H0, generating H2S as a product of the anaerobic respiration. It was also determined that, without cathodic polarization, the conditions are not enough to reduce the H+ generated by the H2S dissociation (Pd is not susceptible to corrosion at this condition. On the other hand, cathodic polarization increased the permeation current, which was associated with the maximum enzymatic activity phase of the bacteria.En este trabajo se estudió la permeación del hidrógeno proveniente de una cepa pura de bacterias sulfato reductoras-BSR (Desulfovibrio desulfuricans ssp. desulfuricans, utilizando para ello el tipo de celda de permeación de hidrógeno y una lámina de paladio (Pd. Esto se hizo con la finalidad de evaluar la despolarización catódica como mecanismo de acción de las BSR en la corrosión inducida microbiológicamente. Los ensayos de permeación se realizaron sin y con polarización catódica, utilizando un medio de cultivo estéril desaireado e inoculado con 10 % de BSR a una concentración de 108 cel/ml. Los resultados obtenidos indicaron crecimiento en 109-1010 cel/ml a las 18 h tanto en los ensayos sin polarización como en aquellos con polarización, lo cual refleja que la BSR se desarrolla independientemente de una superficie polarizada como fuente de H0, generando H2S como

  20. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility and by...... actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria, the...

  1. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  2. Estudio del horizonte local

    OpenAIRE

    Ros Ferré, Rosa Maria

    2009-01-01

    El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical).

  3. Grupo de Estudios Peirceanos

    OpenAIRE

    Jaime Nubiola; Sara F. Barena

    2001-01-01

    El Grupo de Estudios Peirceanos (http://www.unav.es/gep/index.htm) de la Universidad de Navarra se creó en 1994. Tiene coo objetivo promover el estudio de la obra de Charles S. Peirce (1839-1914), especialmente en España y en los países de lengua castellana, con la convicción deque en su pensamiento pueden encontrarse algunas claves decisivas para la cultura, la ciencia y la filosofía del siglo XXI. El Grupo proporciona un ámbito para el inter...

  4. Peritonitis bacteriana espontánea: estudio en pacientes cirróticos descompensados con ascitis Spontaneous bacterial peritonitis in decompensated cirrhotic patients with ascites

    Directory of Open Access Journals (Sweden)

    Fernando Montoya Maya

    1995-02-01

    Full Text Available Se realizó un estudio descriptivo prospectivo entre febrero de 1993 y marzo de 1994. Se estudiaron 25 pacientes cirróticos (3 de ellos en dos ocasiones con ascitis clínica o ecográfica que ingresaron al servicio de Medicina Interna del Hospital Universitario San Vicente de Paúl, Medellín, Colombia, por descompensación de su cuadro clínico. A todos se les practicó paracentesis diagnóstica con estudio de citoquímico, citología y cultivo para bacterias aerobias y anaerobias. La edad promedio de los pacientes fue de 43.9 años (13 a 77 afíos, 13 fueron mujeres (52% y 12 hombres (48%. En 11 episodios (39.3% se encontró ascitis infectada, así: ascitis bacteriana 6 casos (54.6% (monomicrobiana en tres y polimicrobiana en otros tres; peritonitis bacteriana espontánea 3 casos (27.2% (polimicrobiana en dos y monomicrobiana en uno y ascitis neutrofílica dos casos (18.2%. El 72.7% de los casos con ascitis infectada tuvieron fiebre contra un 23.5% de aquéllos sin infección (p < 0.014. Asimismo, el dolor abdominal fue un síntoma bastante frecuente (45.5% de infección. La ascitis infectada se presentó únicamente en individuos categoría C de la clasificación de Child-Pugh, con niveles séricos de albúmina, generalmente menores de 2 g/dl (p < 0.01. Los niveles de albúmina en líquido ascítico menores de 1 g/dl no se asociaron a la infección del mismo. Los gérmenes prevalentes fueron Escherichia coli y estreptococos del grupo viridans, cada uno aislado en 5 ocasiones. Los aislamientos fueron polimicrobianos en 5 de nueve casos (55.5%. La mortalidad por ascitis infectada fue de 27.3% (3/11 casos comparable con la debida a causas diferentes (29.4% en individuos con ascitis sin infección (5/17. Se concluye que la infección del líquido ascítico es una complicación frecuente en los pacientes cirróticos descompensados. La fiebre y el dolor abdominal son los signos clínicos cardinales de la infección. El aislamiento frecuente de E

  5. Observador Asintótico Ajustable para Reactores Bioquímicos: Aplicación a la Digestión Anaerobia A Tunable Asymptotic Observer for Biochemical Reactors: Application to Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    V. Alcaraz

    2004-01-01

    Full Text Available En este trabajo se propone un observador asintótico ajustable para sistemas dinámicos no lineales que pueden ser descritos por un conjunto de ecuaciones diferenciales ordinarias. A diferencia de los observadores asintóticos clásicos, este observador está provisto de ganancias variables que pueden ser ajustadas por el usuario. En la etapa inicial de la estimación, este observador es robusto frente a perturbaciones inducidas por un conocimiento parcial de los términos no lineales. Eventualmente, este observador es totalmente independiente de los términos no lineales, lo que le confiere una robustez total frente a cualquier perturbación inducida por estos términos. El observador es probado mediante simulaciones rigurosas y es aplicado a un modelo dinámico de digestión anaerobia para el tratamiento de aguas residuales, mostrando propiedades excelentes de convergencia, estabilidad y desempeño. La respuesta del observador propuesto es más rápida que la obtenida con los observadores asintóticos clásicosIn this paper a tunable asymptotic observer for non-linear dynamic systems that can be described by a set of ordinary differential equations, is proposed. In contrast with classical asymptotic observers, this one is provided with variable gains that can be tuned by the user. At the first stage of the estimation, the observer is robust against disturbances induced by poorly known non-linear terms. Eventually, the observer becomes fully independent of the nonlinear terms and thus robust against any disturbance induced by the nonlinear terms. The performance of the observer is tested through rigorous simulations in a dynamic anaerobic digestion model for wastewater treatment, showing excellent convergence and stability properties. Finally, it is shown that the proposed observer yields faster estimates than those obtained by using the classical asymptotic observers

  6. Rumen bacteria

    International Nuclear Information System (INIS)

    The rumen is the most extensively studied gut community and is characterized by its high population density, wide diversity and complexity of interactions. This complex, mixed microbial culture is comprised of prokaryote organisms including methane-producing archaebacteria, eukaryote organisms, such as ciliate and flagellate protozoa, anaerobic phycomycete fungi and bacteriophage. Bacteria are predominant (up to 1011 viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (104-106/g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 102-104/g distributed over 5 genera). The occurrence of bacteriophage is well documented (107-109 particles/g). This section focuses primarily on the widely used methods for the cultivation and the enumeration of rumen microbes, especially bacteria, which grow under anaerobic conditions. Methods that can be used to measure hydrolytic enzymes (cellulases, xylanases, amylases and proteinases) are also described, along with cell harvesting and fractionation procedures. Brief reference is also made to fungi and protozoa, but detailed explanations for culturing and enumerating these microbes is presented in Chapters 2.4 and 2.5

  7. Grupo de Estudios Peirceanos

    Directory of Open Access Journals (Sweden)

    Jaime Nubiola

    2001-01-01

    Full Text Available El Grupo de Estudios Peirceanos (http://www.unav.es/gep/index.htm de la Universidad de Navarra se creó en 1994. Tiene coo objetivo promover el estudio de la obra de Charles S. Peirce (1839-1914, especialmente en España y en los países de lengua castellana, con la convicción deque en su pensamiento pueden encontrarse algunas claves decisivas para la cultura, la ciencia y la filosofía del siglo XXI. El Grupo proporciona un ámbito para el intercambio de ideas acerca de la obra de Peirce, el pragmatismo americano, su recepción en Europa y en el mundo hispánico, y otros temas afines y desde sus comienzos ha contado con la participación de distintos campos como historia, lingüística, literatura, filosofía de la ciencia, derecho, teoría de la comunicación y teología.

  8. un estudio comparativo

    Directory of Open Access Journals (Sweden)

    Federico Varona

    2007-01-01

    Full Text Available La comunicación efectiva es uno de los mayores retos que tienen hoy las organizaciones y empresas tanto a nivel nacional como internacional (global. Este artículo presenta los resultados de la investigación realizada por un equipo internacional de investigadores interesados en descubrir y comparar las conductas comunicativas o estilos de comunicación de los empleados finlandeses y mexicanos cuando interactúan con sus superiores. Para ello presentamos: primero, un breve marco teórico del estudio; segundo, la metodología; tercero, los resultados del análisis estadístico comparativo entre los empleados de Finlandia y México; cuarto, las conclusiones generales y su explicación cultural; y quinto, las implicaciones teóricas y prácticas de este estudio con respecto a las competencias comunicativas necesarias para la comunicación efectiva entre empleados y superiores tanto en organizaciones nacionales como internacionales (globales.

  9. HYDROLYSIS AND METHANOGENIC PHASE OF ANAEROBIC DIGESTION OF SEWAGE SLUDGE AND URBAN SOLID WASTE = HIDRÓLISIS Y FASE METANOGÉNICA DE LA DIGESTIÓN ANAEROBIA DE LODOS DE DEPURADORA Y RESIDUOS SÓLIDOS URBANOS

    Directory of Open Access Journals (Sweden)

    Tânia Forster Carneiro

    2012-01-01

    Full Text Available This paper presents and discusses the feasibility of the mesophilic anaerobic digestion of the sewage sludge and urban solid waste. The experiment consists in the implementation of anaerobic reactors for sewage sludge operating under mesophilic (35º C and semi-continuous (TRS 30 and 20 days and using two different sources of inoculum (30% inoculation and digested sludge urban waste. The thermal effects, chemical, physical and biological treatment of sewage sludge and MSW to methane and carbon dioxide were investigated either separately or jointly. Finally, chemical parameters of the hydrolysis and methanogenic phases of these materials are described and compared in order to provide useful information on the factors limiting the anaerobic digestion as well as to suggest the best way to carry out the process on a large scale. = Este trabajo presenta y discute la viabilidad de los procesos anaerobios mesofílicos de lodos de depuradora y residuos sólidos urbanos. El experimento consiste en la puesta en marcha de reactores anaerobios de lodos de depuradora operando en condiciones mesofílicas (35º C y semi-continua (TRS 30 y 20 días y utilizando dos distintas fuentes de inóculo (30% de inoculación: lodos digeridos y residuos urbanos. Los efectos térmicos, químicos, físicos y biológicos de los tratamientos de los lodos de depuradora y del RSU hasta el metano y el dióxido de carbono son investigados ya sea por separado o conjuntamente. Por último, los parámetros químicos de la hidrólisis y de la fase metanogénica de estos materiales son descritos y comparados con el fin de proporcionar información útil sobre los factores que limitan la digestión anaerobia, así como para sugerir la mejor manera de llevar a cabo el proceso a gran escala.

  10. Estudio de competencias del teleformador

    OpenAIRE

    Marcelo, Carlos

    2005-01-01

    El Servicio Andaluz de Empleo de la Consejeria de Empleo de la Junta de Andalucia ha realizado un Estudio de Competencias del Teleformador. Este estudio establece un análisis de competencias necesarias para el diseño, desarrollo y gestión de acciones de e-Learning.

  11. Back To Bacteria.

    Science.gov (United States)

    Flannery, Maura C.

    1997-01-01

    Explores new research about bacteria. Discusses bacterial genomes, archaea, unusual environments, evolution, pathogens, bacterial movement, biofilms, bacteria in the body, and a bacterial obsession. Contains 29 references. (JRH)

  12. Cuantificación, aislamiento e identificaciónde comunidades anaerobias amilolíticas de un manantial termomineral de Paipa, Boyacá

    Directory of Open Access Journals (Sweden)

    Posada Yully

    2004-12-01

    Full Text Available Se cuantif icaron microorganismos anaerobios termofílicos amilolíticos de un manantial termomineral en la región andina (5° 45' 69’’ N, 73° 6' 61’’ W, 2500 msnm a través del Número Más Probable (NMP. Los recuentos microbianos de las poblaciones presentaron valores entre 1,9*102 células/100 mL y 5.8*102 células/100 mL en presencia de almidón y tiosulfato como aceptor de electrones y 1,4*102células/100 mL y 3,4*102 células/100 mL en presencia solamente de almidón. Se realizaron aislamientos microbianos a partir de las últimas diluciones positivas del NMP y se aislaron 8 cepas bacterianas denominadas P4-6, P4-7, P4-8, P4-9, P4-10, P4-11, P4-12 y P4-13. Estas cepas crecieron a temperaturas óptimas entre 60 y 65 °C, y exhibieron un metabolismo fermentativo. El principal producto de fermentación fue etanol seguido de acetato, CO2 e hidrógeno. El tiosulfato fue utilizado como aceptor externo de electrones, pero el sulfato o el hierro férrico no fue reducido. La diversidad filogenética de estas 8 cepas fue evaluada por medio de geles de electroforesis de gradiente denaturalizante (DGGE. Se analizó la secuencia del gen 16S rRNA de dos de las cepas aisladas (P4-6 y P4-9 y el análisis indicó que éstas pertenecen a la familia Thermoanaerobiaceae del dominio Bacteria. Del análisis fenotípico y genotípico se deduce que estos organismos pertenecen al género Thermoanaerobacter, y con base en el análisis de las secuencias del 16S rDNA se observa una similitud del 98% con Thermoanaerobacter italicus y Thermoanaerobacter mathranii. Palabras clave: termofilia, manantiales termominerales, anaerobiosis, Thermoanaerobacter, DGGE.

  13. y casos de estudios

    Directory of Open Access Journals (Sweden)

    Esteban Valenzuela Van Treek

    2006-01-01

    latinoamericanas, adentrándose en las problemáticas de la más relevantes, así como reflexionar sobre el presente de ellas, tomando para esto algunos casos de estudio.. “En el caso de las áreas metropolitanas, la concentración y el crecimiento de las grandes ciudades con fenómenos de nuevas barriadas, de municipios limítrofes y de ciudades dormitorios, dentro o fuera del término de la gran ciudad, demandan soluciones administrativas de conjunto que superen los esquemas municipales tradicionales” (Barrero, 1993. Esto lleva a definir el problema de estudio de como la aglomeración de población en áreas superiores a las ciudades tradicionales en América Latina, constituyen formas diferentes a los planos nacionales y municipales, por lo que urge crear condiciones para el bienestar de sus ciudadanos. Es necesario para esto, el comprender el sistema político de manera dinámica y variable, el cual esta íntimamente ligado a la constitución a la deriva estructural de las sociedades, pero sobretodo al gobierno de la ciudad, elemento fundante de la civilización occidental en la cual estamos situados.

  14. MEXCODE* CASO DE ESTUDIO

    Directory of Open Access Journals (Sweden)

    Gabriel Arturo García Gómez

    2000-01-01

    Full Text Available El caso plantea la reactivación de un proyecto que se presentó en el año 1995 como alternativa para el desarrollo del centro del Valle y mejora de la eficiencia en el manejo del comercio exterior de la Cuenca Pacífica. El proyecto se revivió a raíz de la necesidad de la compañía patrocinadora de mejorar sus flujos de caja proyectados y la reciente autorización para su funcionamiento. El proyecto es el popularmente denominado “Puerto Seco” de la ciudad de Guadalajara de Buga, internamente nombrado Mexcode. Los estudios iniciales estaban encaminados a que el proyecto fuera manejado por el municipio de Buga, sin embargo, posteriormente se vio la necesidad de buscar que pasara a manos de la empresa privada. El municipio, después de analizar las propuestas de varios inversionistas de la región en las cuales se evaluaba la ubicación dentro de la zona de los predios de sus empresas, su área, proximidad a la línea férrea y a la doble calzada Buga-Tuluá (sitio de paso del 80% de la carga de importación y exportación por Buenaventura y evaluar aspectos relativos a su trayectoria empresarial y compromiso con el desarrollo de la región, decidió otorgarle el proyecto al Grupo Empresarial Agri-Supplies S.A.

  15. Bacteria isolated from amoebae/bacteria consortium

    Science.gov (United States)

    Tyndall, Richard L.

    1995-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  16. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

  17. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  18. un objeto de estudio emergente

    Directory of Open Access Journals (Sweden)

    Vanesa Aidée Ramírez Vázquez

    2007-01-01

    Full Text Available El interés de este artículo es mostrar, de manera muy general, los textos que la revista Estudios sobre las Culturas Contemporáneas (ESCC ha publicado desde su creación refi eridas al campo de las Tecnologías de Información y Comunicación (TIC. No se incluyen los estudios sobre la radio y la televisión pues se considera que merecen un tratamiento especial como medios masivos de comunicación con mayor tiempo en el escenario social; se centra, en cambio, en los estudios relativos a las computadoras, Internet, videojuegos, celulares, satélites, redes, chat, lo que se ha dado en llamar Nuevas Tecnologías de Información y Comunicación (NTIC.

  19. Estudio de funciones con geogebra

    OpenAIRE

    Benedicto Baldonado, Clara

    2012-01-01

    Nuestra investigación, “Estudio de funciones con GeoGebra”, se ha desarrollado en el “Máster Universitario en Profesor de Educación Secundaria” de la Universitat de València. El estudio se centra en cómo alcanzar una correcta comprensión de los conceptos referidos a funciones haciendo uso del GeoGebra. El problema que motiva esta investigación radica en que, en los cursos tradicionales de 2º de Bachillerato, cantidades significativas de estudiantes no logran comprender los conceptos básico...

  20. Aislamiento y caracterización de bacterias quitinolíticas ruminales

    OpenAIRE

    Piloni Martini, Javier

    2012-01-01

    Los principales objetivos del presente estudio fueron aislar y seleccionar bacterias ruminales quitinolíticas con alta capacidad para degradar quitina pura y caparazón de camarón in vitro, e identificar genéticamente a las bacterias seleccionadas usando secuencias de su gen 16S rARN amplificado mediante PCR. El aislamiento de las bacterias ruminales se inicio con un cultivo mixto liofilizado de bacterias quitinolíticas (CMBQ) obtenido de borregos alimentados con una dieta con 25% de caparazón...

  1. Genomics of Probiotic Bacteria

    Science.gov (United States)

    O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

    Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

  2. Learning Chemistry from Bacteria

    OpenAIRE

    Clardy, Jon

    2013-01-01

    Dr. Jon Clardy Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Harvard University All animals, including humans, originated and evolved on a planet already teeming with bacteria, and the two kingdoms of life have been competing and cooperating through their joint history. Although bacteria are most familiar as pathogens, some bacteria produce small molecules that are essential for the biology of animals and other eukaryotes. This lecture explores some of...

  3. Interacción bacteria-microalga en el ambiente marino y uso potencial en acuicultura Microalgae and bacteria interaction in the aquatic environment and their potential use in aquaculture

    OpenAIRE

    CARLOS E. RIQUELME; RUBÉN E. AVENDAÑO-HERRERA

    2003-01-01

    El presente estudio tiene como objetivo revisar el conocimiento generado sobre el rol que juegan las interacciones bacteria-microalga en ambientes marinos y dulceacuícolas, definiendo las posibles aplicaciones que puede tener el conocimiento de estas interacciones en el manejo de las aguas costeras y sistemas acuícolas. Los antecedentes proporcionados en este análisis permiten sugerir que bacterias y/o microalgas, constituyen una alternativa para el control de proliferaciones de bacterias y f...

  4. Aerobic Anoxygenic Phototrophic Bacteria

    OpenAIRE

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynt...

  5. Los estudios latinoamericanistas en Finlandia

    Directory of Open Access Journals (Sweden)

    Elina Vuola

    2010-07-01

    Full Text Available El artículo responde a las preguntas propuestas por la Coordinación de este número para componer una imagen de la situación y perspectivas de los estudios latinoamericanos en Finlandia.Latin American Studies in FinlandThis article answers the questions posed by the Coordination of this Number in order to paint a global picture of the current situation and perspectives of Latin American Studies in Finland.

  6. Estudio plataformas IoT

    OpenAIRE

    Loureiro Garrido, Rubén

    2015-01-01

    El objetivo principal de este proyecto consiste en dar una visión global del Internet de las cosas. Se comenzará describiendo los ámbitos de aplicación más importantes hoy día, siguiendo por el estudio de las principales plataformas software/hardware y, por último, se presentará una aplicación real cuyo objetivo principal es demostrar de una forma práctica lo descrito anteriormente.

  7. Fortaleciendo experiencias en estudios cooperativos

    OpenAIRE

    Revista Institucional de la Facultad de Ciencias Económicas

    2011-01-01

    Como todos los años docentes del Instituto de Estudios Cooperativos de la Facultad de Ciencias Económicas intercambian en el país y en el exterior experiencias en el campo de la investigación, la docencia y la extensión vinculados al movimiento cooperativo. (Párrafo extraído del texto a modo de resumen)

  8. Metallization of bacteria cells

    Institute of Scientific and Technical Information of China (English)

    LI; Xiangfeng; (黎向锋); LI; Yaqin; (李雅芹); CAI; Jun; (蔡军); ZHANG; Deyuan; (张德远)

    2003-01-01

    Bacteria cells with different standard shapes are well suited for use as templates for the fabrication of magnetic and electrically conductive microstructures. In this paper, metallization of bacteria cells is demonstrated by an electroless deposition technique of nickel-phosphorus initiated by colloid palladium-tin catalyst on the surfaces of Citeromyces matritensis and Bacillus cereus. The activated and metallized bacteria cells have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). Results showed that both Citeromyces matritensis and Bacillus cereus had no deformation in shape after metallization; the metallized films deposited on the surfaces of bacteria cells are homogeneous in thickness and noncrystalline in phase structure. The kinetics of colloid palladium-tin solution and electroless plating on bacteria cells is discussed.

  9. Indicator For Pseudomonas Bacteria

    Science.gov (United States)

    Margalit, Ruth

    1990-01-01

    Characteristic protein extracted and detected. Natural protein marker found in Pseudomonas bacteria. Azurin, protein containing copper readily extracted, purified, and used to prepare antibodies. Possible to develop simple, fast, and accurate test for marker carried out in doctor's office.

  10. Estudios sobre plantas andinas, x

    OpenAIRE

    Cuatrecasas, José

    2012-01-01

    Durante la preparación del género Baccharis para Prima Flora Colombiana tuve que estudiar gran número de especies andinas, tropicales y extratropicales de fuera de Colombia; el objeto principal de tales estudios fue el de tipificar las especies íntimamente relacionadas con las colombianas y establecer su diferenciación taxonómica. La consulta de los tipos específicos y la identificación de gran número de colecciones procedentes de las regiones andinas hasta el sur del continente americano per...

  11. Centauros Mensajeros - Casos de estudio

    OpenAIRE

    Bolívar Ramírez, Jorge Enrique

    2012-01-01

    El estudio del caso de la empresa Centaurus Mensajeros es presentado en un documento estructurado en tres partes, donde primero se expone la historia y las características del proyecto; luego se presenta su entorno empresarial; y finalmente, se muestra un ejemplo de emprendimiento a través de la historia de vida del empresario y fundador de esta organización, así como su gestión, cualidades como empresario y lucha por mantener la empresa de Centaurus Mensajeros como una de las más reconocidas...

  12. Estudio de Salud Agrícola

    Science.gov (United States)

    En 1993, científicos del Instituto Nacional del Cáncer, Instituto Nacional de Ciencias Ambientales y la Agencia de Protección Ambiental de Estados Unidos iniciaron un estudio conocido como Estudio de Salud Agrícola (AHS).

  13. Oil eating bacteria

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    The article discusses the unusual technology of using oil-eating bacteria to increase oil recovery. The background for the discovery that bacteria injection into the reservoirs may increase the oil recovery is the study of microbial action in breaking down oil pollution. About 20 per cent of the organisms living naturally in the sea can eat oil. But they need water to grow. In the absence of water, the bacteria produce enzymes to make the oil water soluble and allow them to extract nutrients from them. Oil does not vanish upon being eaten, but enzymes from the digestive process act as effective detergents to wash away the oil, which is then easier to recover.

  14. 090728 Estudio del ensilado biológico de pescado como inóculo de bacterias lácticas en la conservación de desechos pesqueros (Biologic fish silage's study as lactic bacterial inoculums in the fresh offal conservation

    Directory of Open Access Journals (Sweden)

    Llanes Iglesias, José

    2007-09-01

    Full Text Available ResumenEl objetivo de este trabajo fue determinar diferentes porcentajes de miel final (0, 10 y 15 y ensilado biológico de pescado (20, 30 y 50 como inóculo de bacterias lácticas en la conservación de desechos pesqueros, así como evaluar la tecnología de producción continua de ensilado biológico de pescado producido con tres inoculaciones sucesivas de este mismo producto (inóculo bacteriano y dos porcentajes de miel final (10 y 15. Los resultados mostraron que con 10 % de miel final y 30% de ensilado biológico se conservan los desechos pesqueros hasta 10 días y con 10% de miel final y 20 % de ensilado biológico de pescado se logra un producto estable durante dos inoculaciones escalonadas de 72 horas cada una, mientras que con 15% de miel se logran tres inoculaciones con un ahorro de 16,60 USD/Tn. AbstractTo determine different percents (0, 10 and 15 of molasses and biological fish silage (20, 30 and 50 as lactic bacterial inoculums in the fresh offal conservation was the objective of this work; as well as biological fish silage continuous production technology evaluation produced with three consecutive inoculations of biological fish silage (bacterial inoculum and two percent of molasses to silage fresh fish wastes. The results showed that with 10% molasses and 30% of biological fish silage a stable production can be obtained, which last 10 days under storage conditions and with 10% molasses and 20% biological fish silage a stable product is obtained during two consecutive inoculations from 72 hours each one, while 15% molasses three consecutive inoculations are obtained in the same period of time, representing a 16,60 USD/Tn saving.

  15. Immunity to intracellular bacteria

    OpenAIRE

    Stefan H. E. Kaufmann; Follows, George A.; Martin E. Munik

    1992-01-01

    Immunity to intracellular bacteria including Mycobacterium tuberculosis. Mycobacterium leprae, and Listeria monocytogenes depends on specific T cells. Evidence to be described suggests that CD4 (alpha/beta)T cells which interact with each other and with macrophages contribute to acquired resistence against as well as pathogenesis of intracellular bacterial infections.

  16. Immunity to intracellular bacteria

    Directory of Open Access Journals (Sweden)

    Stefan H. E. Kaufmann

    1992-01-01

    Full Text Available Immunity to intracellular bacteria including Mycobacterium tuberculosis. Mycobacterium leprae, and Listeria monocytogenes depends on specific T cells. Evidence to be described suggests that CD4 (alpha/betaT cells which interact with each other and with macrophages contribute to acquired resistence against as well as pathogenesis of intracellular bacterial infections.

  17. Bacterias marinas productoras de compuestos antibacterianos aisladas a partir de invertebrados intermareales Marine bacteria producing antibacterial compounds Isolated from inter-tidal invertebrates

    Directory of Open Access Journals (Sweden)

    Jorge León

    2010-06-01

    Full Text Available Se realizó actividades prospectivas de muestreo de invertebrados intermareales en la Bahía de Ancón (Lima - Perú con el objetivo de seleccionar bacterias marinas productoras de sustancias antimicrobianas. El estudio comprendió el aislamiento de bacterias en agar marino, pruebas de susceptibilidad antimicrobiana in vitro y observaciones de microscopía electrónica. Se reporta el aislamiento, caracterización fenotípica y propiedades antimicrobianas de diez cepas de bacterias marinas que incluyen a los géneros Vibrio, Pseudomonas y Flavobacterium y del orden Actinomycetal que inhiben a patógenos de humanos. Los resultados indicarían que los invertebrados marinos serían fuentes de bacterias productoras de sustancias antibióticas.Prospective sampling activities of intertidal invertebrates in the Ancon Bay (Lima, Peru were done in order to select marine bacteria producing antimicrobial substances. The study included the isolation of bacteria in marine agar, in vitro antimicrobial susceptibility testing and electronic microscopic observations. We report the isolation, phenotypical characterization and antimicrobial properties of 10 strains of marine bacteria including the genus Vibrio, Pseudomonas, and Flavobacterium, and the order Actinomycetae that inhibit human pathogens. The results indicate that the marine invertebrates would be sources of bacteria producing antibiotic substances.

  18. Can bacteria save the planet?

    OpenAIRE

    Hunter, Philip

    2010-01-01

    Bacteria might just hold the key to preserving the environment for our great grandchildren. Philip Hunter explores some of the novel ways in which systems biology and biotechnology are harnessing bacteria to produce renewable energy and clean up pollution.

  19. Cable Bacteria in Freshwater Sediments

    OpenAIRE

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B.; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the fre...

  20. Manufacture of Probiotic Bacteria

    Science.gov (United States)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  1. Exopolysaccharides from Marine Bacteria

    Institute of Scientific and Technical Information of China (English)

    CHI Zhenming; FANG Yan

    2005-01-01

    Microbial polysaccharides represent a class of important products of growing interest for many sectors of industry. In recent years, there has been a growing interest in isolating new exopolysaccharides (EPSs)-producing bacteria from marine environments, particularly from various extreme marine environments. Many new marine microbial EPSs with novel chemical compositions, properties and structures have been found to have potential applications in fields such as adhesives,textiles, pharmaceuticals and medicine for anti-cancer, food additives, oil recovery and metal removal in mining and industrial waste treatments, etc This paper gives a brief summary of the information about the EPSs produced by marine bacteria,including their chemical compositions, properties and structures, together with their potential applications in industry.

  2. Lipoprotein sorting in bacteria.

    Science.gov (United States)

    Okuda, Suguru; Tokuda, Hajime

    2011-01-01

    Bacterial lipoproteins are synthesized as precursors in the cytoplasm and processed into mature forms on the cytoplasmic membrane. A lipid moiety attached to the N terminus anchors these proteins to the membrane surface. Many bacteria are predicted to express more than 100 lipoproteins, which play diverse functions on the cell surface. The Lol system, composed of five proteins, catalyzes the localization of Escherichia coli lipoproteins to the outer membrane. Some lipoproteins play vital roles in the sorting of other lipoproteins, lipopolysaccharides, and β-barrel proteins to the outer membrane. On the basis of results from biochemical, genetic, and structural studies, we discuss the biogenesis of lipoproteins in bacteria, their importance in cellular functions, and the molecular mechanisms underlying efficient sorting of hydrophobic lipoproteins to the outer membrane through the hydrophilic periplasm. PMID:21663440

  3. Bacteria, Phages and Septicemia

    OpenAIRE

    Gaidelytė, Aušra; Vaara, Martti; Bamford, Dennis H.

    2007-01-01

    The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such ph...

  4. Bacteria, food, and cancer

    OpenAIRE

    Rooks, Michelle G.; Garrett, Wendy S.

    2011-01-01

    Gut microbes are essential components of the human organism—helping us metabolize food into energy, produce micronutrients, and shape our immune systems. Having a particular pattern of gut microbes is also increasingly being linked to medical conditions including obesity, inflammatory bowel disease, and diabetes. Recent studies now indicate that our resident intestinal bacteria may also play a critical role in determining one's risk of developing cancer, ranging from protection against cancer...

  5. Lethal Mutagenesis of Bacteria

    OpenAIRE

    Bull, James J; Wilke, Claus O.

    2008-01-01

    Lethal mutagenesis, the killing of a microbial pathogen with a chemical mutagen, is a potential broad-spectrum antiviral treatment. It operates by raising the genomic mutation rate to the point that the deleterious load causes the population to decline. Its use has been limited to RNA viruses because of their high intrinsic mutation rates. Microbes with DNA genomes, which include many viruses and bacteria, have not been considered for this type of treatment because their low intrinsic mutatio...

  6. Bacteria are not Lamarckian

    OpenAIRE

    Danchin, Antoine

    2007-01-01

    Instructive influence of environment on heredity has been a debated topic for centuries. Darwin's identification of natural selection coupled to chance variation as the driving force for evolution, against a formal interpretation proposed by Lamarck, convinced most scientists that environment does not specifically instruct evolution in an oriented direction. This is true for multicellular organisms. In contrast, bacteria were long thought of as prone to receive oriented influences from their ...

  7. Estudio de impacto ambiental: procedimiento y herramientas

    OpenAIRE

    Encinas Malagón, María Dolores; Gómez de Balugera López de Alda, Zuriñe

    2016-01-01

    2ª edición Este trabajo consta de un manual mejorado y ampliado, que detalla los pasos necesarios para la realización de un Estudio de Impacto Ambiental, un libro excel más completo para la evaluación cualitativa y cuantitativa de los impactos ambientales en cada una de las fases del estudio y una colección de los indicadores ambientales necesarios para dicha valoración.

  8. Denitrification by extremely halophilic bacteria

    Science.gov (United States)

    Hochstein, L. I.; Tomlinson, G. A.

    1985-01-01

    Extremely halophilic bacteria were isolated from widely separated sites by anaerobic enrichment in the presence of nitrate. The anaerobic growth of several of these isolates was accompanied by the production of nitrite, nitrous oxide, and dinitrogen. These results are a direct confirmation of the existence of extremely halophilic denitrifying bacteria, and suggest that such bacteria may be common inhabitants of hypersaline environments.

  9. Pepsin homologues in bacteria

    Directory of Open Access Journals (Sweden)

    Bateman Alex

    2009-09-01

    Full Text Available Abstract Background Peptidase family A1, to which pepsin belongs, had been assumed to be restricted to eukaryotes. The tertiary structure of pepsin shows two lobes with similar folds and it has been suggested that the gene has arisen from an ancient duplication and fusion event. The only sequence similarity between the lobes is restricted to the motif around the active site aspartate and a hydrophobic-hydrophobic-Gly motif. Together, these contribute to an essential structural feature known as a psi-loop. There is one such psi-loop in each lobe, and so each lobe presents an active Asp. The human immunodeficiency virus peptidase, retropepsin, from peptidase family A2 also has a similar fold but consists of one lobe only and has to dimerize to be active. All known members of family A1 show the bilobed structure, but it is unclear if the ancestor of family A1 was similar to an A2 peptidase, or if the ancestral retropepsin was derived from a half-pepsin gene. The presence of a pepsin homologue in a prokaryote might give insights into the evolution of the pepsin family. Results Homologues of the aspartic peptidase pepsin have been found in the completed genomic sequences from seven species of bacteria. The bacterial homologues, unlike those from eukaryotes, do not possess signal peptides, and would therefore be intracellular acting at neutral pH. The bacterial homologues have Thr218 replaced by Asp, a change which in renin has been shown to confer activity at neutral pH. No pepsin homologues could be detected in any archaean genome. Conclusion The peptidase family A1 is found in some species of bacteria as well as eukaryotes. The bacterial homologues fall into two groups, one from oceanic bacteria and one from plant symbionts. The bacterial homologues are all predicted to be intracellular proteins, unlike the eukaryotic enzymes. The bacterial homologues are bilobed like pepsin, implying that if no horizontal gene transfer has occurred the duplication

  10. Bacteria counting method based on polyaniline/bacteria thin film.

    Science.gov (United States)

    Zhihua, Li; Xuetao, Hu; Jiyong, Shi; Xiaobo, Zou; Xiaowei, Huang; Xucheng, Zhou; Tahir, Haroon Elrasheid; Holmes, Mel; Povey, Malcolm

    2016-07-15

    A simple and rapid bacteria counting method based on polyaniline (PANI)/bacteria thin film was proposed. Since the negative effects of immobilized bacteria on the deposition of PANI on glass carbon electrode (GCE), PANI/bacteria thin films containing decreased amount of PANI would be obtained when increasing the bacteria concentration. The prepared PANI/bacteria film was characterized with cyclic voltammetry (CV) technique to provide quantitative index for the determination of the bacteria count, and electrochemical impedance spectroscopy (EIS) was also performed to further investigate the difference in the PANI/bacteria films. Good linear relationship of the peak currents of the CVs and the log total count of bacteria (Bacillus subtilis) could be established using the equation Y=-30.413X+272.560 (R(2)=0.982) over the range of 5.3×10(4) to 5.3×10(8)CFUmL(-1), which also showed acceptable stability, reproducibility and switchable ability. The proposed method was feasible for simple and rapid counting of bacteria. PMID:26921555

  11. Beneficial bacteria inhibit cachexia.

    Science.gov (United States)

    Varian, Bernard J; Goureshetti, Sravya; Poutahidis, Theofilos; Lakritz, Jessica R; Levkovich, Tatiana; Kwok, Caitlin; Teliousis, Konstantinos; Ibrahim, Yassin M; Mirabal, Sheyla; Erdman, Susan E

    2016-03-15

    Muscle wasting, known as cachexia, is a debilitating condition associated with chronic inflammation such as during cancer. Beneficial microbes have been shown to optimize systemic inflammatory tone during good health; however, interactions between microbes and host immunity in the context of cachexia are incompletely understood. Here we use mouse models to test roles for bacteria in muscle wasting syndromes. We find that feeding of a human commensal microbe, Lactobacillus reuteri, to mice is sufficient to lower systemic indices of inflammation and inhibit cachexia. Further, the microbial muscle-building phenomenon extends to normal aging as wild type animals exhibited increased growth hormone levels and up-regulation of transcription factor Forkhead Box N1 [FoxN1] associated with thymus gland retention and longevity. Interestingly, mice with a defective FoxN1 gene (athymic nude) fail to inhibit sarcopenia after L. reuteri therapy, indicating a FoxN1-mediated mechanism. In conclusion, symbiotic bacteria may serve to stimulate FoxN1 and thymic functions that regulate inflammation, offering possible alternatives for cachexia prevention and novel insights into roles for microbiota in mammalian ontogeny and phylogeny. PMID:26933816

  12. Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    ToddKlaenhammer

    2013-04-01

    Full Text Available Lactic acid bacteria (LAB are a diverse group of Gram-positive bacteria found in a vast array of environments including dairy products and the human gastrointestinal tract. In both niches, surface proteins play a crucial role in mediating interactions with the surrounding environment. The sortase enzyme is responsible for covalently coupling a subset of surface dependent proteins (SDPs to the cell wall of Gram-positive organisms through recognition of a conserved C-terminal LPXTG motif. Genomic sequencing of LAB and annotation has allowed for the identification of sortase and SDPs. Historically, sortase and SDPs were predominately investigated for their role in mediating pathogenesis. Identification of these proteins in LAB has shed light on their important roles in mediating nutrient acquisition through proteinase P as well as positive probiotic attributes including adhesion, mucus barrier function, and immune signaling. Furthermore, sortase expression signals in LAB have been exploited as a means to develop oral vaccines targeted to the gastrointestinal tract. In this review, we examine the collection of studies which evaluate sortase and SDPs in select species of dairy associated and health promoting LAB.

  13. Caracterización de bacterias halófilas productoras de amilasas aisladas de las salinas de san blas en junín

    OpenAIRE

    Pamela Elizabeth Canales Mormontoy; Elizabeth Liz Chávez Hidalgo; Amparo Iris Zavaleta Pesantes

    2014-01-01

    Título en español: Caracterización de bacterias halófilas productoras de amilasas aisladas de las Salinas de San Blas en JunínTítulo en ingles: Characterization of halophilic bacteria producing amylase isolated from San Blas Salterns in JuninTítulo corto: Bacterias halófilas amilolíticas de las Salinas de San BlasResumen:  El objetivo de este estudio fue caracterizar bacterias halófilas con actividad amilolítica provenientes de las Salinas de San Blas-Junín, ubicadas en los Andes peruanos apr...

  14. Estudio de la ecología de Bacillus thuringiensis en la hoja

    OpenAIRE

    Maduell Soler, Pau

    2008-01-01

    La ecología de Bacillus thuringiensis, un bioinsecticida muy común, es poco conocida. Nuestro principal objetivo era investigar acerca de la ecología de esta bacteria en la filosfera. En un primer estudio se recogieron 35 muestras de hojas del género Piper de bosques andinos colombianos. Se obtuvieron 256 aislamientos de B. thuringiensis del 74% de las muestras estudiadas. Los aislamientos fueron caracterizados según la morfología del cristal, la presencia de genes cry por PCR y la toxicidad ...

  15. Aislamiento y caracterización in vitro de una bacteria acetogénica ruminal

    OpenAIRE

    Rodríguez Carrillo, Jaime Azael

    2012-01-01

    La producción de metano (CH4) en rumiantes representa una pérdida de energía metabólica para el animal y contribuye en la generación de gases efecto invernadero. Una alternativa para disminuir la producción de CH4 en los rumiantes, es desarrollando inoculos de bacterias acetogénicas que compitan con las bacterias metanogénicas por los sustratos utilizados en la producción de metano. En el presente estudio se usó un medio de cultivo selectivo a base de formato y líquido rum...

  16. Potencial probiótico de las bacterias lácticas del vino

    OpenAIRE

    García-Ruiz, Almudena; González de Llano, Dolores; García-Cayuela, Tomás; Requena, Teresa; Bartolomé, Begoña; Moreno-Arribas, M. Victoria

    2013-01-01

    Con el objetivo de explorar el potencial efecto beneficioso para la salud de las principales especies de bacterias lácticas del vino, en este trabajo se ha realizado un estudio sistemático in vitro de caracterización de la funcionalidad probiótica de una colección de cepas de bacterias lácticas enológicas de los géneros Lactobacillus y Pediococcus, y de la especie Oenococcus oeni, empleándose dos cepas probióticas, Lactobacillus plantarum CLC 17 y L. fermentum CECT 5716, como control. Inicial...

  17. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus;

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  18. Immunomodulatory properties of probiotic bacteria

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen

    2007-01-01

    Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria is...... cytokines when stimulated with bacteria, and the cytokine pattern induced by specific bacteria resembled the pattern induced in MoDC, except for TNF-alpha and IL-6, which were induced in response to different bacteria in blood DC/monocytes and monocyte-derived DC. Autologous NK cells produced IFN-gamma when...... cultured with blood DC, monocytes and monocyte-derived DC and IL-12-inducing bacteria, whereas only DC induced IFN-gamma production in allogeneic T cells. In vitro-generated DC is a commonly used model of tissue DC, but they differ in certain aspects from intestinal DC, which are in direct contact with the...

  19. Interactions between Diatoms and Bacteria

    OpenAIRE

    Amin, Shady A.; Parker, Micaela S.; Armbrust, E. Virginia

    2012-01-01

    Summary: Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding hi...

  20. Radiation-resistant asporogenic bacteria

    International Nuclear Information System (INIS)

    This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned. (Tsukamoto, Y.)

  1. La Escuela de Estudios Hispano-Americanos

    OpenAIRE

    Bernabéu Albert, Salvador

    2010-01-01

    La Escuela de Estudios Hispano-Americanos es una institución cultural, perteneciente al Consejo Superior de Investigaciones Científicas, dedicada al estudio del Americanismo desde 1942 a la actualidad. Está encuadrada en el sector de Humanidades, una de las ocho áreas científico-técnicas en que se organiza el CSIC, el mayor organismo público de investigación en España. Paralelamente a los profundos cambios que están ocurriendo en la Universidad española con el Plan de ...

  2. Bacteria, phages and septicemia.

    Directory of Open Access Journals (Sweden)

    Ausra Gaidelyte

    Full Text Available The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such phages were also detected in the initial blood cultures, indicating that phages are circulating in the blood at the onset of sepsis. The fact that most of the septicemic bacterial isolates carry functional prophages suggests an active role of phages in bacterial infections. Apparently, prophages present in sepsis-causing bacterial clones play a role in clonal selection during bacterial invasion.

  3. Bacteriophages of methanotrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tyutikow, F.M. (All-Union Research Inst. for Genetics and Selection of Industrial Microorganisms, Moscow, USSR); Bespalova, I.A.; Rebentish, B.A.; Aleksandrushkina, N.N.; Krivisky, A.S.

    1980-10-01

    Bacteriophages of methanotrophic bacteria have been found in 16 out of 88 studied samples (underground waters, pond water, soil, gas and oil installation waters, fermentor cultural fluids, bacterial paste, and rumen of cattle) taken in different geographic zones of the Soviet Union. Altogether, 23 phage strains were isolated. By fine structure, the phages were divided into two types (with very short or long noncontractile tails); by host range and serological properties, they fell into three types. All phages had guanine- and cytosine-rich double-stranded deoxyribonucleic acid consisting of common nitrogen bases. By all of the above-mentioned properties, all phages within each of the groups were completely identical to one another, but differed from phages of other groups.

  4. Beer spoilage bacteria and hop resistance

    NARCIS (Netherlands)

    Sakamoto, K; Konings, WN

    2003-01-01

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and Mega

  5. Sampling bacteria with a laser

    Science.gov (United States)

    Schwarzwälder, Kordula; Rutschmann, Peter

    2014-05-01

    Water quality is a topic of high interest and it's getting more and more important due to climate change and the implementation of European Water Framework Directive (WFD). One point of interest here is the inflow of bacteria into a river caused by combined sewer overflows which lead untreated wastewater including bacteria directly into a river. These bacteria remain in the river for a certain time, they settle down and can be remobilised again. In our study we want to investigate these processes of sedimentation and resuspension and use the results for the development of a software module coupled with the software Flow3D. Thereby we should be able to simulate and therefore predict the water quality influenced by combined sewer overflows. Hence we need to get information about the bacteria transport and fate. We need to know about the size of the bacteria or of the bacteria clumps and the size of the particles the bacteria are attached to. The agglomerates lead to different characteristics and velocities of settlement. The timespan during this bacteria can be detected in the bulk phase depends on many factors like the intensity of UV light, turbidity of the water, the temperature of the water, if there are grazers and a lot more. The size, density and composition of the agglomerates is just a part of all these influencing factors, but it is extremely difficult to differ between the other effects if we have no information about the simple sedimentation in default of these basic information. However we have a big problem getting the data. The chaining between bacteria or bacteria and particles is not too strong, so filtering the water to get a sieving curve may destroy these connections. We did some experiments similar to PIV (particle image velocimetry) measurements and evaluated the pictures with a macro written for the software ImageJ. Doing so we were able to get the concentration of bacteria in the water and collect information about the size of the bacteria. We

  6. Screening of aspartate dehydrogenase of bacteria

    OpenAIRE

    Fukuda, Shoko; Okamura, Tokumitsu; Yasumasa, Izumi; Takeno, Tomomi; Ohsugi, Masahiro

    2001-01-01

    Fifty-two strains of bacteria cultured under aerobic conditions and 12 strains of bacteria cultured under anaerobic conditions demonstrated high activity staining of aspartate dehydrogenase with NAD^+. Four strains of bacteria cultured under aerobic conditions and 7 strains of bacteria cultured under anaerobic conditions demonstrated high activity staining of aspartate dehydrogenase with NADP^+. Seven strains of bacteria cultured under aerobic conditions and 4 strains of bacteria cultured und...

  7. Estudios de competitividad en sistemas urbano - territoriales

    Directory of Open Access Journals (Sweden)

    Esteban Soms García

    2015-03-01

    El Ministerio de Planificación y Cooperación de Chile, ha desarrollado varios estudios relacionados con la competitividad regional, destinados a pronosticar y evaluar los impactos positivos y negativos que podrían derivarse de los recientes Acuerdos de Libre Comercio suscritos por Chile con la Comunidad Europea, Estados Unidos y Corea, más los acuerdos ad portas con los Países de la APEC. En lo referente a competitividad urbana, destacan algunos estudios y proyectos relacionados con el programa gubernamental "Ciudades para el Bicentenario", impulsado el Ministerio de Vivienda y Urbanismo y los Gobiernos Regionales de Antofagasta, Bio Bio, Valparaíso y Santiago.

  8. Estrategia organizacional: una propuesta de estudio

    Directory of Open Access Journals (Sweden)

    Ángela Lucía Noguera Hidalgo

    2014-01-01

    Full Text Available El concepto de estrategia en el contexto de las organizaciones empresariales es uno de los temas que genera gran interés en los asuntos del management. Sin embargo, la proposición de nuevos enfoques no ha aportado significativamente al avance en el estudio de este concepto. El estancamiento se hace evidente, razón por la cual el presente documento esboza una propuesta que reúne algunos de los retos para el estudio de la estrategia. En él se presenta una revisión que deja por sentados los posibles caminos a seguir, los cuales contribuyen a la perdurabilidad de las organizaciones.

  9. Estudio de impacto ambiental: Procedimiento y herramientas

    OpenAIRE

    Peche González, Roberto; Encinas Malagón, María Dolores; Gómez de Balugera López de Alda, Zuriñe; Ortuzar Iragorri, María Arritokieta

    2008-01-01

    Este trabajo consta de un manual donde se detallan los pasos necesarios para realizar un Estudio de Impacto Ambiental, acompañado de un libro excel donde se llevarán a cabo las operaciones necesarios para la valoración cualitativa y cuantitativa de los impactos ambientales, así como la colección de indicadores ambientales necesarios para dicha valoración.

  10. Sewage-pollution indicator bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Rodrigues, V.; Alwares, E.; Rodrigues, C.; Baksh, R.; Jayan, S.; Mohandass, C.

    increased. It is only recently that sewage from major cities like Panaji, Goa, India is treated before disposing into the estuary. It is therefore of interest to determine what the levels of pollution indicator bacteria due to sewage disposal...

  11. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.;

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The...... TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  12. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  13. Adherention ability of intestinal bacteria

    OpenAIRE

    Morgensternová, Tereza

    2014-01-01

    Probiotics are live microorganisms that provide positive health benefits. Bacteria of the genus Bifidobacterium belong to this group. These bacteria have to meet a number of criteria so that they could be considered for probiotic. These include the ability to survive, grow, and be metabolically active in the gastrointestinal tract of the recipient. Probiotics protect the intestinal mucus from the adhesion of pathogenic organisms. The aim of this thesis was to test the ability of different ...

  14. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.; Piskur, Jure

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The...... TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  15. A comparative effect of 3 disinfectants on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The disinfection effect of chlorine dioxide, chlorine and their mixture on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria in circulating cooling water was studied. The results of the test indicated that high purity chlorine dioxide was the most effective biocide in the 3 disinfectants, and with a dosage of 0.5mg/L, chlorine dioxide could obtain perfect effect. High purity chloride dioxide could have the excellent effect with the pH value of 6 to 10, and could keep it within 72 h. Chlorine and their mixture couldn't reach the effect of chlorine dioxide.

  16. Cable Bacteria in Freshwater Sediments.

    Science.gov (United States)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-09-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage. PMID:26116678

  17. Bioreporter bacteria for landmine detection

    Energy Technology Data Exchange (ETDEWEB)

    Burlage, R.S. [Oak Ridge National Lab., TN (United States); Youngblood, T. [Frisby Technologies, Aiken, SC (United States); Lamothe, D. [American Technologies, Inc., Huntsville, AL (United States). Ordnance/Explosives Environmental Services Div.

    1998-04-01

    Landmines (and other UXO) gradually leak explosive chemicals into the soil at significant concentrations. Bacteria, which have adapted to scavenge low concentrations of nutrients, can detect these explosive chemicals. Uptake of these chemicals results in the triggering of specific bacterial genes. The authors have created genetically recombinant bioreporter bacteria that detect small concentrations of energetic chemicals. These bacteria are genetically engineered to produce a bioluminescent signal when they contact specific explosives. A gene for a brightly fluorescent compound can be substituted for increased sensitivity. By finding the fluorescent bacteria, you find the landmine. Detection might be accomplished using stand-off illumination of the minefield and GPS technology, which would result in greatly reduced risk to the deminers. Bioreporter technology has been proven at the laboratory scale, and will be tested under field conditions in the near future. They have created a bacterial strain that detects sub-micromolar concentrations of o- and p-nitrotoluene. Related bacterial strains were produced using standard laboratory protocols, and bioreporters of dinitrotoluene and trinitrotoluene were produced, screening for activity with the explosive compounds. Response time is dependent on the growth rate of the bacteria. Although frill signal production may require several hours, the bacteria can be applied over vast areas and scanned quickly, producing an equivalent detection speed that is very fast. This technology may be applicable to other needs, such as locating buried explosives at military and ordnance/explosive manufacturing facilities.

  18. Isolation and Identification of Concrete Environment Bacteria

    Science.gov (United States)

    Irwan, J. M.; Anneza, L. H.; Othman, N.; Husnul, T.; Alshalif, A. F.

    2016-07-01

    This paper presents the isolation and molecular method for bacteria identification through PCR and DNA sequencing. Identification of the bacteria species is required in order to fully utilize the bacterium capability for precipitation of calcium carbonate in concrete. This process is to enable the addition of suitable catalyst according to the bacterium enzymatic pathway that is known through the bacteria species used. The objective of this study is to isolate, enriched and identify the bacteria species. The bacteria in this study was isolated from fresh urine and acid mine drainage water, Kota Tinggi, Johor. Enrichment of the isolated bacteria was conducted to ensure the bacteria survivability in concrete. The identification of bacteria species was done through polymerase chain reaction (PCR) and rRDNA sequencing. The isolation and enrichment of the bacteria was done successfully. Whereas, the results for bacteria identification showed that the isolated bacteria strains are Bacillus sp and Enterococus faecalis.

  19. Naturally fermented Jijelian black olives: microbiological characteristics and isolation of lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Karam, Nour-Eddine

    2009-12-01

    Full Text Available A study of the microflora of traditionally fermented black olives in Eastern Algeria is presented. A count of the following microbial groups was carried out: mesophilic bacteria, enterobacteria, lactic acid bacteria (LAB, staphylococci and yeast. In a second phase, the identification and assessment of the technological traits of LAB was performed. Seventeen lactic acid bacteria were isolated and identified. These isolates were represented by two genera: Lactobacillus and Leuconostoc. The results showed that Lactobacillus plantarum was the predominant species in this traditional product.Un estudio sobre la microflora de aceitunas negras fermentada por métodos tradicionales en el Este de Argelia es presentado. Se realizo el siguiente recuento de grupos de microorganismos: bacterias mesófilas, enterobacterias, bacterias ácido lácticas (LAB, staphylococcus y levaduras. En una segunda fase, la identificación y evaluación de aspectos tecnológicos de LAB fue realizada. Setenta bacterias ácido lácticas fueron aisladas e identificadas. Estos aislados contenían principalmente dos géneros: Lactobacillus y Leuconostoc. Los resultados mostraron que Lactobacillus plantarum fue la especie predominante en este producto tradicional.

  20. Estudios sobre postmodernidad y estudios culturales: ¿sinónimos?

    OpenAIRE

    Dr. Roberto A. Follari

    2000-01-01

    La postmodernidad exige para ser comprendida una dimensión sociohistórica y otra filosófica que le resulta irrenunciables. También hay una serie de fenómenos propiamente culturales, que son los que los denominados "estudios culturales" (G. Canclini. M. Barbero, etc.) han asumido en Latinoamérica. Tales estudios han aportado una descripción de fenómenos nuevos, que no son analizados por ningún otro discurso teórico (tribus urbanas, identidades lábiles, influencia de los medios en los nuevos es...

  1. Digestion anaerobia de solidos en alta concentración

    OpenAIRE

    Mandujano Sánchez, Porfirio

    2001-01-01

    La problemática que plantean los residuos sólidos urbanos (RSU) como consecuencia de su incremento y las implicaciones sobrela contaminación ambiental y el agotamiento de los recursos naturales, hace esencial la búsqueda de caminos para su gestión correcta desde el punto de vista ambiental y social. La generación de RSU tiene una triple repercusión medioambiental; contaminación, desperdicio de recursos y la necesidad de espacios para su disposición. En la conferencia de las Naciones Unidas so...

  2. Biodegradación anaerobia de clorofenoles en aguas residuales

    OpenAIRE

    Puyol Santos, Daniel

    2010-01-01

    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada, Sección Departamental de Ingeniería Química; Fecha de lectura: 20/07/2010

  3. CHARACTERIZATION OF HYDROCARBONOCLASTIC MARINE BACTERIA USING THE 16S rRNA GENE: A MICROCOSM CASE STUDY

    OpenAIRE

    DOLLY REVELO ROMO; MARÍA ISABEL GÓMEZ PERDOMO; MARCELA CONCHA OBANDO; DANIEL BRAVO; PABLO FERNÁNDEZ IZQUIERDO

    2013-01-01

    Algunos microorganismos marinos pueden degradar contaminantes derivados del petróleo usándolos como única fuente de carbono y energía. Este grupo heterogéneo es llamado bacterias hidrocarburoclásticas. Sin embargo, se subestima a aquellas bacterias hidrocarburoclásticas que aun no han sido caracterizadas. En este contexto, se llevo a cabo un estudio de microcosmos simulando un ambiente marino impactado con petróleo, en Biorreactores de Flujo Ascendente (BFA). A partir de estos microcosmos fue...

  4. ESTUDIO DE FRACCIONES EN CONTEXTOS SONOROS

    Directory of Open Access Journals (Sweden)

    Alexander Conde

    2016-01-01

    Full Text Available En este ensayo resaltamos los vínculos cognitivos entre las matemáticas y la música, que pueden favorecer procesos de enseñanza y aprendizaje de las fracciones en la matemática escolar. Las actividades exhibidas provienen de una investigación que promueve experiencias sensoriales en el campo rítmico para favorecer la construcción de nociones matemáticas. Dichas actividades posibilitan un engranaje armónico entre las matemáticas y la música convergentes en el tiempo y el sonido como los objetos de estudio común entre éstas disciplinas. El análisis de la investigación que aquí reportamos es producto de la aplicación de las actividades en diferentes programas de formación de profesorado de México y Francia, alrededor de la enseñanza y aprendizaje de las matemáticas en contextos interdisciplinarios. Este análisis se desarrolló desde tres categorías referentes a las nociones de unidad relativa, relación parte-parte y equipartición, las cuales son nociones fundamentales para el estudio de las fracciones en la matemática escolar. Encontramos que la enseñanza con enfoque integrador requiere no solo conocimientos especializados, sino un cambio de creencias en torno a las opiniones del profesorado sobre la organización del currículo, su enseñanza y la manera en que aprende la población estudiantil. Un aporte de esta experiencia es ofrecer a docentes elementos teóricos y didácticos para el estudio de las fracciones en contextos interdisciplinarios.

  5. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    Directory of Open Access Journals (Sweden)

    Rojas, J.

    2008-01-01

    Full Text Available The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bacteria in latex paint were demonstrated.

  6. Electron transport chains of lactic acid bacteria

    OpenAIRE

    Brooijmans, R.J.W.

    2008-01-01

    Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic bacteria. Lactococcus lactis, and several other lactic acid bacteria, however respond to the addition of heme in aerobic growth conditions. This response includes increased biomass and robustness. In t...

  7. Los estudios americanistas y la JAE

    OpenAIRE

    Bernabéu Albert, Salvador; Naranjo Orovio, Consuelo

    2007-01-01

    Las propuestas de fomento de los estudios americanistas y de intercambio cultural y científico entre España y sus antiguas colonias, como una nueva forma de acercamiento que trajera el entusiasta Rafael Altamira tras su viaje americano (1909-1910), tuvieron buena acogida en diferentes medios académicos y gubernamentales. En su plan destacaba la creación de una sección americanista en Oviedo y el inicio del intercambio cultural con Hispanoamérica a través del envío de profesores...

  8. GranjaLAB : Centro de Estudios Avanzados

    OpenAIRE

    CERRATO HERNÁNDEZ, BERNARDO

    2015-01-01

    El Centro de Estudios Avanzados forma parte de las intervenciones pensadas para el Parque Natural de Urbasa y Andía. El objetivo del proyecto es diseñar un espacio apto para acoger a los investigadores que realizarán actividades relacionadas con los valores naturales del parque, como la protección del ecosistema, la conservación de la biodiversidad y el desarrollo sostenible de la zona. Los científicos deberán elaborar una guía indicando las características del parque ...

  9. Centro de estudios avanzados, Baquedano (Navarra)

    OpenAIRE

    Damià Vera, Irene

    2012-01-01

    Cabe destacar la intención de camuflar el edificio e integrarlo en el entorno para que el impacto visual sea mínimo, ya que se encuentra ubicado en una reserva natural de la biosfera. La cubierta está concebida como quinta fachada. El programa de laboratorios se completa con una biblioteca y una pequeña cafetería. Ciafarone, AC. (2011). Centro de estudios avanzados. Baquedano, Navarra. http://hdl.handle.net/10251/15652. Archivo delegado

  10. Estudio retrospectivo de 145 dientes supernumerarios

    OpenAIRE

    Fernández Montenegro, P.; Valmaseda Castellón, E.; Berini Aytés, Leonardo; Gay Escoda, Cosme

    2006-01-01

    Objetivo: El presente estudio retrospectivo pretende describir la distribución de los dientes supernumerarios en una población de pacientes que acuden a una Unidad ambulatoria de Cirugía Bucal. Introducción: Los dientes supernumerarios y la hiperodoncia múltiple se asocian normalmente con diferentes síndromes como el de Gardner o con fisuras faciales; sin embargo, pueden aparecer en pacientes sin ningún tipo de patología. Su prevalencia oscila entre el 0,5 y el 3,8% en la dentición permane...

  11. Estudio comparativo de la cultura organizacional

    OpenAIRE

    Góngora, Norberto H.; Nóbile, Cecilia; Reija, Lucía

    2014-01-01

    El presente trabajo da a conocer resultados parciales de la investigación realizada en el marco del proyecto acreditado “Estudio de las Culturas Organizacionales como determinantes de las personas que trabajan en ellas”, cuyo objetivo general es corroborar las características de cada tipo cultural descriptas en la teoría.Los datos que se exponen son el resultado de varios proyectos de investigación desarrollados utilizando la misma metodología. Se ha obtenido gran cantidad de información para...

  12. Un estudio de resentimiento en ancianos institucionalizados

    OpenAIRE

    Dante Gazzolo D.; Cecilia Romero A.; Ramón León D.; Carlos Aldana N.

    1987-01-01

    El presente estudio es una investigación realizada por los Servicios de Psicología del Instituto Nacional de Salud Mental "Honorio Delgado - Hideyo Noguchi", y del Hogar "lgnacia Rodulfa V da. de Canevaro", a través del cual se intenta un acercamiento al devenir psicológico del anciano institucionalizado. Este, al residir permanentemente al interior de un asilo, manifiesta sentimientos de frustración, fracaso y resentimiento, entre otros. Se intenta determinar el grado de: resentimiento que s...

  13. Diabetes en México. Estudio CARMELA

    OpenAIRE

    Jorge Escobedo-de la Peña; Luisa Virginia Buitrón-Granados; Jesús Cenobio Ramírez-Martínez; Raymundo Chavira-Mejía; Herman Schargrodsky; Beatriz Marcet Champagne

    2011-01-01

    Introducción, La diabetes ha mostrado un crecimiento epidémico en México, país que ocupa uno de los primeros lugares en el mundo en cuanto a su frecuencia. El objetivo de este trabajo fue analizar la prevalencia de la diabetes tipo 2 en la Ciudad de México y su asociación con algunos factores de riesgo cardiovascular. Material y métodos, Se realizó un estudio transversal. Se seleccionaron aleatoriamente 1722 adultos de 25 a 64 años de edad, de uno y otro sexo. Se estimó la prevalencia de diab...

  14. Motivaciones para el estudio en universitarios

    OpenAIRE

    Mas Tous, Carmen; Medinas Amorós, Magdalena

    2007-01-01

    En la actualidad, en la universidad española se debate sobre la adaptación al Espacio Europeo de Educación Superior. Esta adaptación implica un nuevo concepto de la docencia universitaria, en el que se replantea el papel del profesor y se enfatiza la importancia de la capacidad de aprendizaje autónomo por parte del alumno. El presente estudio tuvo su origen en varias preguntas surgidas de la práctica diaria de la docencia universitaria en Psicología: ¿qué motiva a estudiar a nuestros universi...

  15. Estudios micológicos colombianos. dothideales

    OpenAIRE

    2012-01-01

    Las exploraciones micológicas en Colombia han sido relativamente pocas; no es de extrañarlo porque la Micología es una ciencia que apenas comienza a desarrollarse en nuestro país.  Los estudios más extensos e interesantes los efectuaron Chardón y Toro en los años de 1926 a 1929, siendo bien conocida la publicación que de ellos hicieron en 1930, con el título de “Micological Exploratios of Colombia”.  Recolecciones posteriores han acrecentado un poco el número lo suficientemente elevado como p...

  16. Anorexia nervosa: un estudio de casos

    OpenAIRE

    Lillyana Zusman Tinman

    2013-01-01

    La Anorexia Nervosa es un trastorno de alimentación que se define (etimológicamente) como una "pérdida nerviosa del apetito". Se caracteriza por la actitud consciente, voluntaria y rotunda de los sujetos  de tener un exceso de peso que intentan modificar por vía de la inanición. A partir del estudio de casos, se propone la distinción entre una Anorexia Nervosa Estructural -aquella en la que predomina el conflicto intrapsíquico primario y arcaico, y que manifiesta una conducta aislada y retraí...

  17. Apoyo conductual positivo: estudio de un caso

    OpenAIRE

    Redondo Redondo, Patricia

    2015-01-01

    Este trabajo se ha realizado con el propósito de investigar el programa de Apoyo Conductual Positivo (APC). Específicamente en este trabajo presentamos el estudio de un caso, un alumno con trastorno del espectro autista escolarizado en un centro de educación especial. Para ello se ha realizado una revisión bibliográfica de la discapacidad, se ha conceptualizado la discapacidad intelectual y los trastornos del espectro autista, se ha repasado brevemente los autores más representativos de la mo...

  18. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon and...... nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico analyses revealed the presence of three to nine chitinases in each strain, however the number of chitinases...... chitin regulatory system.Conclusions: This study has provided insight into the ecology of chitin degradation in marine bacteria. It also served as a basis for choosing a more efficient chitin degrading production strain e.g. for the use of chitin waste for large-scale fermentations....

  19. Methylotrophic bacteria in sustainable agriculture.

    Science.gov (United States)

    Kumar, Manish; Tomar, Rajesh Singh; Lade, Harshad; Paul, Diby

    2016-07-01

    Excessive use of chemical fertilizers to increase production from available land has resulted in deterioration of soil quality. To prevent further soil deterioration, the use of methylotrophic bacteria that have the ability to colonize different habitats, including soil, sediment, water, and both epiphytes and endophytes as host plants, has been suggested for sustainable agriculture. Methylotrophic bacteria are known to play a significant role in the biogeochemical cycle in soil ecosystems, ultimately fortifying plants and sustaining agriculture. Methylotrophs also improve air quality by using volatile organic compounds such as dichloromethane, formaldehyde, methanol, and formic acid. Additionally, methylotrophs are involved in phosphorous, nitrogen, and carbon cycling and can help reduce global warming. In this review, different aspects of the interaction between methylotrophs and host plants are discussed, including the role of methylotrophs in phosphorus acquisition, nitrogen fixation, phytohormone production, iron chelation, and plant growth promotion, and co-inoculation of these bacteria as biofertilizers for viable agriculture practices. PMID:27263015

  20. Parotitis due to anaerobic bacteria.

    Science.gov (United States)

    Matlow, A; Korentager, R; Keystone, E; Bohnen, J

    1988-01-01

    Although Staphylococcus aureus remains the pathogen most commonly implicated in acute suppurative parotitis, the pathogenic role of gram-negative facultative anaerobic bacteria and strict anaerobic organisms in this disease is becoming increasingly recognized. This report describes a case of parotitis due to Bacteroides disiens in an elderly woman with Sjögren's syndrome. Literature reports on seven additional cases of suppurative parotitis due to anaerobic bacteria are reviewed. Initial therapy of acute suppurative parotitis should include coverage for S. aureus and, in a very ill patient, coverage of gram-negative facultative organisms with antibiotics such as cloxacillin and an aminoglycoside. A failure to respond clinically to such a regimen or isolation of anaerobic bacteria should lead to the consideration of the addition of clindamycin or penicillin. PMID:3287567

  1. La perspectiva cualitativa en los estudios sobre pobreza

    OpenAIRE

    Mateo Pérez, Miguel A.

    2002-01-01

    Los estudios sobre pobreza internacional han estado marcados por el enfoque cuantitativo. Sin embargo desde hace unos años los estudios cualitativos están adquiriendo una gran relevancia. Este artículo presenta las características de un estudio cualitativo sobre pobreza y género realizado en España durante los últimos tres años, estableciendo algunas líneas de trabajo básicas para el estudio de la pobreza desde la perspectiva cualitativa.

  2. Debate sobre estudios postcoloniales y subalternos

    Directory of Open Access Journals (Sweden)

    David Morris

    2001-01-01

    Full Text Available A partir de los comentarios a la reseña elaborada por Ian S. Mclean sobre el libro: Cuerpos incas y el cuerpo de Cristo. El Corpus Christi en Cuzco colonial, Perú, escrito por Carolyn Dean, surge un debate sobre los Estudios Postcoloniales y Subalternos, que se desarrolló entre el 12 de agosto y el 3 de septiembre de 2001, a través de la lista de correo electrónico de H-Latam, grupo de discusión dedicado a la historia latinoamericana. En él participaron destacados especialistas en el tema, quienes analizaron, entre otras cuestiones, el uso de la jerga y las formas de escritura, la novedad de sus planteamientos, sus influencias filosóficas y epistemológicas, su pretensión de captar el punto de vista de los vencidos y subordinados, la pertinencia de unas ideas originalmente desarrolladas para el estudio del colonialismo inglés y luego aplicadas al colonialismo español en América Latina.

  3. Programmed survival of soil bacteria

    DEFF Research Database (Denmark)

    Jensen, Lars Bogø; Molin, Søren; Sternberg, Claus;

    Biological containment systems have been developed for Pseudomonas putida and related soil bacteria. The systems are based on combinations of lethal genes and regulated gene expression. Two types of killing function have been employed: 1) A membrane protein interfering with the membrane potential...

  4. Role of Bacteria in Oncogenesis

    OpenAIRE

    Chang, Alicia H; Parsonnet, Julie

    2010-01-01

    Summary: Although scientific knowledge in viral oncology has exploded in the 20th century, the role of bacteria as mediators of oncogenesis has been less well elucidated. Understanding bacterial carcinogenesis has become increasingly important as a possible means of cancer prevention. This review summarizes clinical, epidemiological, and experimental evidence as well as possible mechanisms of bacterial induction of or protection from malignancy.

  5. Engineering robust lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Bokhorst-van de Veen, van H.; Wels, M.; Kleerebezem, M.

    2011-01-01

    For centuries, lactic acid bacteria (LAB) have been industrially exploited as starter cultures in the fermentation of foods and feeds for their spoilage-preventing and flavor-enhancing characteristics. More recently, the health-promoting effects of LAB on the consumer have been widely acknowledged,

  6. Fuzzy species among recombinogenic bacteria

    Directory of Open Access Journals (Sweden)

    Fraser Christophe

    2005-03-01

    Full Text Available Abstract Background It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species. Results Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'. Conclusion A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.

  7. El estudio de Trichinella spiralis en modelos experimentales.

    Directory of Open Access Journals (Sweden)

    Alejandra Moreno G

    2012-07-01

    Full Text Available ResumenSe presenta una breve descripción del estudio de Trichinella spiralis en modelos experimentales, enfocándonos al estudio de la epidemiología, técnicas diagnósticas directas e indirectas, tratamiento y biología del parasito.

  8. El estudio de Trichinella spiralis en modelos experimentales.

    OpenAIRE

    Alejandra Moreno G; Claudia Maldonado T; Isabel Chávez Ruvalcaba; Rosa G Reveles H; Zuleika Quiroz Núñez; José J. Muñoz E

    2012-01-01

    ResumenSe presenta una breve descripción del estudio de Trichinella spiralis en modelos experimentales, enfocándonos al estudio de la epidemiología, técnicas diagnósticas directas e indirectas, tratamiento y biología del parasito.

  9. Síntesis: Resultados iniciales del Estudio Nacional de Ex

    Science.gov (United States)

    El 4 de noviembre de 2010, el Estudio Nacional de Exámenes de Pulmóndio a conocer resultados iniciales que indican que hubo 20% menos muertes por cáncer de pulmón entre los participantes del estudio evaluados con tomografía computarizada espiral de baja d

  10. Physico-chemical factors and bacteria in fish ponds

    OpenAIRE

    Jun, X.; Xiuzheng, F.; Tongbing, Y.

    2000-01-01

    Analyses of pond water and mud samples show that nitrifying bacteria (including ammonifying bacteria, nitrite bacteria, nitrobacteria and denitrifying bacteria) are in general closely correlated with various physico-chemical factors, ammonifying bacteria are mainly correlated with dissolved oxygen; denitrifying bacteria are inversely correlated with phosphorus; nitrite bacteria are closely correlated with nitrites, nitrobacteria are inversely correlated with ammoniac nitrogen. The nitrifying ...

  11. Un estudio sobre el rendimiento universitario

    Directory of Open Access Journals (Sweden)

    Albaladejo Pina, I. P.

    1999-01-01

    Full Text Available El objetivo del presente trabajo es contrastar los rendimientos académicos de alumnos de dos cursos de la Facultad de Ciencias Económicas y Empresariales de la Universidad de Murcia, uno con el antiguo plan de estudios y otro con el actualmente en vigor. Analizamos el éxito y el fracaso para los estudiantes de cada uno de estos cursos, así como las variables socioeconómicas y educacionales que pueden influir en su rendimiento. Comprobamos, mediante unas estimaciones logit, que tanto unas como otras variables son factores condicionantes de este rendimiento. En particular, destacamos la influencia de haber cursado la opción C de COU en cuanto a fracasar o no en su primer curso universitario.

  12. Lista de estudios de Dominique Reyre

    OpenAIRE

    2016-01-01

    Onomástica literaria «La mystérieuse identité d’un personnage de Gil Vicente: Mofina Mendes», Bulletin des Études Portugaises et Brésiliennes, 39-40, 1978-1979, pp. 13-18. Dictionnaire des noms des personnages du «Don Quichotte» de Cervantes. Suivi d’une analyse structurale et linguistique, Paris Éditions Hispaniques, 1980, 231 p. «De Cerv-ante(s) à Rocin-ante ou comment inverser son destin par la création onomastique», La Licorne, Poitiers, 1997, pp. 241-248. «Estudio onomástico», en Jean-M...

  13. Actividades desarrolladas en la colección de bacterias marinas

    OpenAIRE

    Morales, M; Ortiz, E.; Villaverde, M.; V Caballero; Fonseca, E. L.; Núñez, R.

    2006-01-01

    En la Colección de Bacterias Marinas se conservan aislamientos procedentes de diferentes regiones del archipiélago cubano. Aquí se desarrollan actividades de investigación y servicios, entre las primeras se encuentran los estudios para la conservación de las cepas a mediano y largo plazo, la determinación taxonómica de sus componentes, la evaluación de bioactividades con aplicación en la industria médico-farmacéutica y en el saneamiento ambiental y la actualización de la base de datos asociad...

  14. Método molecular para la detección de bacterias productoras de aminas

    OpenAIRE

    Rivas, Blanca de las; Marcobal. Ángela; Carrascosa, Alfonso V.; Muñoz, Rosario

    2008-01-01

    En este estudio se describe un sencillo método molecular mediante PCR que permite la detección de las bacterias presentes durante el proceso de vinificación que potencialmente pueden producir aminas biógenas (histamina, tiramina, putrescina, cadaverina y feniletilamina). El método consiste en un conjunto de oligonucleótidos específicos para la detección de cada uno de los genes que codifican las enzimas encargadas de la síntesis de aminas biógenas. Las aminas biógenas se sintetizan por la acc...

  15. Estudio sobre encofrados de madera modernos

    Directory of Open Access Journals (Sweden)

    de la Peña Aznar, Juan M.

    1980-12-01

    Full Text Available The author continues the development of the subject «Modern Timber Formwork», by summing up the comparative examination —already carried out in Part III of this Study— of the different types of glued timber existing on the market. In addition, the loads and stresses allovk/able for coniferous timber and the proposal for establishing Regulations for the Timber Section of the Research and Experimental Forestry Institute of Spain are given. In part V of the author's Study, published in this article, the important subject of the glues used for joining timber, a truly vital point in order to obtain louvered timber beams which are simply glued together, is approached.

    El autor continúa el desarrollo del tema sobre «Encofrados de madera modernos», resumiendo el estudio comparativo —ya hecho en la Parte III de este Estudio— de las diferentes vigas de madera encolada existentes en el mercado dando, además, las cargas y tensiones admisibles para maderas coníferas y la propuesta de Reglamentación de la Sección de Maderas del Instituto Forestal de Investigaciones y Experiencias de España. En la parte V del Estudio del autor, publicada en este artículo, se aborda el importante tema de las colas empleadas para las uniones de madera, algo realmente vital para la obtención de vigas de madera en celosía simplemente encoladas.

  16. Smokeless Tobacco May Contain Potentially Harmful Bacteria

    Science.gov (United States)

    ... 160769.html Smokeless Tobacco May Contain Potentially Harmful Bacteria Infections, diarrhea and vomiting are possible consequences, FDA ... products can harbor several species of potentially harmful bacteria, researchers warn. Two types in particular -- Bacillus licheniformis ...

  17. Killer Pigments in Bacteria: An Ecological Nightmare.

    Science.gov (United States)

    Benathen, Isaiah A.; Saccardi, Marion

    2000-01-01

    Describes an alternative to teaching ecology by using bacteria to test competitor survival. Students observe a time-dependent selective killing of other unrelated bacteria by Pseudomonas aeruginosa. (SAH)

  18. Estudios sobre postmodernidad y estudios culturales: ¿sinónimos?

    Directory of Open Access Journals (Sweden)

    Dr. Roberto A. Follari

    2000-01-01

    Full Text Available La postmodernidad exige para ser comprendida una dimensión sociohistórica y otra filosófica que le resulta irrenunciables. También hay una serie de fenómenos propiamente culturales, que son los que los denominados "estudios culturales" (G. Canclini. M. Barbero, etc. han asumido en Latinoamérica. Tales estudios han aportado una descripción de fenómenos nuevos, que no son analizados por ningún otro discurso teórico (tribus urbanas, identidades lábiles, influencia de los medios en los nuevos estilos de consumo, etc.. Con ello se da cuenta de parte de la cuestión postmodernidad, pero sin dudase deja fuera otras: lo filosófico y aún lo social y lo político quedan fuera de esa especie de antropología del presente. Por lo tanto, un enfoque integral de lo postmoderno incluye los estudios culturales, pero está lejos de limitarse a ellos.

  19. Re-engineering bacteria for ethanol production

    Science.gov (United States)

    Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

    2014-05-06

    The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

  20. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    OpenAIRE

    Rojas, J

    2008-01-01

    The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bac...

  1. Genetics of Lactic Acid Bacteria

    Science.gov (United States)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  2. Aggregation Patterns in Stressed Bacteria

    CERN Document Server

    Tsimring, L S; Aranson, I S; Ben-Jacob, E; Cohen, I; Shochet, O; Tsimring, Lev; Levine, Herbert; Aranson, Igor; Ben-Jacob, Eshel; Cohen, Inon; Shochet, Ofer

    1995-01-01

    We study the formation of spot patterns seen in a variety of bacterial species when the bacteria are subjected to oxidative stress due to hazardous byproducts of respiration. Our approach consists of coupling the cell density field to a chemoattractant concentration as well as to nutrient and waste fields. The latter serves as a triggering field for emission of chemoattractant. Important elements in the proposed model include the propagation of a front of motile bacteria radially outward form an initial site, a Turing instability of the uniformly dense state and a reduction of motility for cells sufficiently far behind the front. The wide variety of patterns seen in the experiments is explained as being due the variation of the details of the initiation of the chemoattractant emission as well as the transition to a non-motile phase.

  3. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  4. Dissipative Shocks behind Bacteria Gliding

    CERN Document Server

    Virga, Epifanio G

    2014-01-01

    Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. We prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed.

  5. Box-shaped halophilic bacteria.

    OpenAIRE

    Javor, B; Requadt, C; Stoeckenius, W

    1982-01-01

    Three morphologically similar strains of halophilic, box-shaped procaryotes have been isolated from brines collected in the Sinai, Baja California (Mexico), and southern California (United States). Although the isolates in their morphology resemble Walsby's square bacteria, which are a dominant morphological type in the Red Sea and Baja California brines, they are probably not identical to them. The cells show the general characteristics of extreme halophiles and archaebacteria. They contain ...

  6. Folate Production by Probiotic Bacteria

    OpenAIRE

    Stefano Raimondi; Alberto Amaretti; Maddalena Rossi

    2011-01-01

    Probiotic bacteria, mostly belonging to the genera Lactobacillus and Bifidobacterium, confer a number of health benefits to the host, including vitamin production. With the aim to produce folate-enriched fermented products and/or develop probiotic supplements that accomplish folate biosynthesis in vivo within the colon, bifidobacteria and lactobacilli have been extensively studied for their capability to produce this vitamin. On the basis of physiological studies and genome analysis, wild-typ...

  7. Magnetotactic Bacteria from Extreme Environments

    OpenAIRE

    Lefèvre, Christopher T; Dennis A. Bazylinski

    2013-01-01

    Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI) in water columns or sediments of aqu...

  8. Bacteria interfere with A-actinomycetemcomitans colonization

    OpenAIRE

    Teughels, Wim; Haake, S. Kinder; Sliepen, Isabelle; Pauwels, Martine; Van Eldere, Johan; Cassiman, Jean-Jacques; Quirynen, Marc

    2007-01-01

    It is known that beneficial bacteria can suppress the emergence of pathogenic bacteria, particularly in the gastrointestinal tract. This study examined the potential for a similar suppression of Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans colonization of epithelial cells, due to its potential relevance in periodontal diseases. Seven presumed beneficial bacteria were examined for their ability to interfere, exclude, or displace A. actinomycetemcomitans from epithelial cells...

  9. Laser-Based Identification of Pathogenic Bacteria

    Science.gov (United States)

    Rehse, Steven J.

    2009-01-01

    Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

  10. Magnetotactic bacteria at the geomagnetic equator

    International Nuclear Information System (INIS)

    Magnetotatic bacteria are observed in freshwater and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments. (Author)

  11. Drosophila lifespan enhancement by exogenous bacteria

    OpenAIRE

    Brummel, Ted; Ching, Alisa; Seroude, Laurent; Simon, Anne F.; Benzer, Seymour

    2004-01-01

    We researched the lifespan of Drosophila under axenic conditions compared with customary procedure. The experiments revealed that the presence of bacteria during the first week of adult life can enhance lifespan, despite unchanged food intake. Later in life, the presence of bacteria can reduce lifespan. Certain long-lived mutants react in different ways, indicating an interplay between bacteria and longevity-enhancing genes.

  12. Interacción bacteria-microalga en el ambiente marino y uso potencial en acuicultura Microalgae and bacteria interaction in the aquatic environment and their potential use in aquaculture

    Directory of Open Access Journals (Sweden)

    CARLOS E. RIQUELME

    2003-12-01

    Full Text Available El presente estudio tiene como objetivo revisar el conocimiento generado sobre el rol que juegan las interacciones bacteria-microalga en ambientes marinos y dulceacuícolas, definiendo las posibles aplicaciones que puede tener el conocimiento de estas interacciones en el manejo de las aguas costeras y sistemas acuícolas. Los antecedentes proporcionados en este análisis permiten sugerir que bacterias y/o microalgas, constituyen una alternativa para el control de proliferaciones de bacterias y fitoplancton causantes de efectos dañinos en ambientes naturales y sistemas cerrados de cultivo. Además, las interacciones específicas entre bacteria-microalga permitiría la optimización de sistemas productivos en la industria acuícola. Sin embargo, los mecanismos de estas interacciones son pobremente entendidos. Futuras investigaciones debieran ser dirigidas a comprender el modo de acción de las interacciones bacteria-microalga a nivel molecularThe objective of this survey is to review the knowledge generated with respect to the role of bacteria-microalgae interaction play in marine and fresh environments, and to define the possible application of these microorganisms on the management of costal water and aquaculture systems. This review proposes that bacteria and/or microalgae are an alternative to control the proliferation of bacteria and phytoplankton that cause damages in natural environments or in closed culture systems. Also, the knowledge of specific interactions between bacteria and microalgae will allow the optimization of productive systems in aquaculture. However, until date the mechanisms involved in these interactions are poorly understood. Therefore, future investigations should be directed towards understanding the mode of action of such interactions at a molecular level

  13. Diálogos sobre juventudes : Estudios de otras miradas

    OpenAIRE

    Fornasari, María Elisa; Decca, Lorena

    2012-01-01

    Medina, Gabriel (ed.) (2009). Juventudes, territorios de identidad y tecnologías. Círculo de Reflexiones de Estudios Poscoloniales. Universidad Autónoma de la Ciudad de México. México. Los estudios sobre juventud/es han seguido diversas trayectorias y han sido abordados desde diferentes perspectivas a partir de su visibilización como problemática. El libro de Gabriel Medina parte de un diagnóstico: la existencia de importantes vacíos en los estudios sobre lo joven y la vigencia de trabajos...

  14. Estudio primera fase del mapa de ruido de Cartagena

    OpenAIRE

    Martínez Moreno, Carlos Alberto

    2015-01-01

    El proyecto de la Primera Fase del Mapa de Ruido de Cartagena, está contemplado como el primer estudio de tráfico rodado del municipio en la zona delimitada de Aglomeración, que conjunto con los diversos estudios y fases realizadas posteriormente, darán como resultado el mapa de ruido del Municipio global, así como los porcentajes de población afectada. En esta primera Fase nos hemos centrado en el estudio del ruido producido por el tráfico rodado en la zona delimitada. Escuela Técnica Sup...

  15. ESTUDIOS DE VISITANTES A MUSEOS (VISITOR STUDIES IN MUSEUMS)

    OpenAIRE

    Rodríguez Sánchez Keilyn

    2011-01-01

    Resumen:Este artículo ofrece un estudio bibliográfico en torno a las investigaciones sobre la relación entre la museografía y sus visitantes. El objetivo central de este documento consiste en elaborar una clasificación de esos estudios en programas de investigación de manera que sirva de punto de partida para la construcción de una pedagogía del Museo. Para este fin, se utiliza la propuesta de Schulman, sobre tipificación de estudios en programas de investigación y, al respecto, se plantean c...

  16. Los estudios de comunicación: disciplina o indisciplina

    Directory of Open Access Journals (Sweden)

    Ma. del Carmen De la Peza Casares

    2013-01-01

    Full Text Available En este artículo la autora sitúa la emergencia de los estudios de comunicación en el contexto sociohistórico del desarrollo de las ciencias sociales y la crisis de paradigmas en los años noventa del siglo pasado. Así mismo, reflexiona sobre las ventajas y desventajas de que dicho campo de estudio se constituya en una disciplina y su impacto en el desarrollo futuro de los estudios de comunicación en México y América Latina.

  17. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    OpenAIRE

    Alix M Denoncourt; Paquet, Valérie E.; Charette, Steve J.

    2014-01-01

    Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging...

  18. Politica de gratuidad: un estudio de caso

    Directory of Open Access Journals (Sweden)

    Everly Castellar Paternina

    2015-01-01

    Full Text Available Este artículo presenta los resultados de una investigación con diseño de estudio de caso de corte cualitativo, cuyo propósito fue analizar, en el marco de la política pública en Colombia, los alcances de la implementación de la gratuidad en una Institución educativa (IE oficial en Barranquilla en el periodo 2008-2012. En la metodología se combinan técnicas cualitativas, como la entrevista semiestructurada, y técnicas cuantitativas como un cuestionario “Ad hoc”. Se hizo un análisis documental y de contenido de los documentos expedidos por el Ministerio de Educación Nacional y la IE. Se aplicó la técnica del análisis de regresión simple para revisar el comportamiento de las variables independientes en este caso gratuidad y las variables dependientes como son cobertura, matrícula y deserción que permitiera realizar un contraste de los alcances y efectos de la gratuidad en la IE objeto de estudio. Por último, se realizó una triangulación con el fin de unir las diferentes técnicas para que nos arrojaran los resultados de esta investigación que en este caso indicaron que: i. La gratuidad se aplica conforme a los lineamientos del decreto 4807 de 2011; ii. Los lineamientos para la implementación y el seguimiento a la gratuidad no se comunican a los padres de familia; iii. Los docentes no tienen claridad sobre la destinación específica de los rubros de calidad; iv. La deserción no tiene una relación directa con la política de gratuidad y la gratuidad no tiene relación directa con la reducción de la tasa de deserción; v. La IE debe mejorar el sistema de comunicación con los padres; vi. La gratuidad está más relacionada con el acceso que con la calidad de los aprendizajes.

  19. PARATIROIDECTOMIA ENDOSCOPICA. ESTUDIO EXPERIMENTAL EN EL PERRO

    Directory of Open Access Journals (Sweden)

    Jorge Ramón Lucena Olavarrieta

    2008-01-01

    Full Text Available La primera paratiroidectomía exitosa fue realizada en Viena, Austria, en 1925. Los procedimientos laparoscópicos estuvieron inicialmente limitadas a las zonas corporales con cavidades preexistentes, recientemente, el acceso a espacios anatómicos potenciales ha extendido las indicaciones de la cirugía endoscópica minimamnete invasiva.Desde el primer reporte sobre la paratiroidectomía endoscópica en 1996, las técnicas video-asistidas han comenzado a utilizarse en la cirugía del cuello, y en varias series se han documentado la factibilidad y seguridad de este tipo de abordaje. La finalidad de esta investigación fue el determinar la factibilidad, seguridad y eficacia de la paratiroidectomía endoscopia en el modelo canino.Entre el 25 de noviembre del 2005 y 15 de octubre del 2007, se intervinieron en el Instituto de Cirugía Experimental de la Universidad Central de Venezuela 31 perros, mestizos sanos desparasitados,asignándose a dos grupos: homogéneos "A" 16, a cirugía convencional, "B" 15 a cirugía video-asistida. Se midieron las siguientes variables; sexo, peso, exámenes de laboratorio, laringoscopia pre y postoperatoria, posición, dirección de la incisión, longitud, localización, valores pre y postoperatorios de calcio, fósforo, proteína C reactiva, hemoglobina, hematocrito, tipo de disección, número y posición de las paratiroides, identificación de los nervios recurrentes y rama externa del nervio laríngeo superior, sangramiento, dificultades intraoperatorias, tiempo, resultado del estudio histopatológico.Las deducciones de este estudio experimental proporcionan evidencias de que la paratiroidectomía endoscópica es factible y segura. El abordaje mínimo tiene mejores resultados cosméticos y el potencial de disminuir la morbi-mortalidad.

  20. Microbiologia Endodóntica

    Directory of Open Access Journals (Sweden)

    Alberto Antonio Olarte Alzamora

    2013-12-01

    Full Text Available Los microorganismos desempeñan un papel importante como iniciadores y contribuyentes significativos de la enfermedad inflamatoria de la pulpa dental y tejidos periapicales. Sin ellos no habría trastornos endodónticos. Su disminución o eliminación durante los procedimientos terapéuticos es decisiva para la reparación posterior al tratamiento y la evolución satisfactoria del caso. Las bacterias aisladas frecuentemente de pulpas necróticas infectadas son: Bacterias anaerobias estrictas y bacterias anaerobias facultativas.

  1. Distimia: estudio descriptivo y rasgos de personalidad.

    Directory of Open Access Journals (Sweden)

    Sergio Ocio León

    1994-01-01

    Full Text Available Se exponen los resultados de una investigación sobre una muestra de pacientes distímicos, diagnosticados siguiendo criterios CIE-10, Ya los que se realizó la sección E (Depresión de la CIDI Medular (primera versión autorizada de la Entrevista Diagnóstica Compuesta. Los datos en que se ha centrado el estudio son: sociodemografía, antecedentes de trastorno psiquiátrico, características clínicas y rasgos de personalidad (según el cuestionario de personalidad 16-PF. Los resultados nos acercaron al conocimiento del trastorno distímico, así como al manejo de la CIE-10. Destaca el carácter objetivamente moderado de la sintomatología distímica, su frecuente asociación a lo largo de la evolución con otro trastorno depresivo, y la existencia de unos rasgos de personalidad predominantes en este tipo de pacientes

  2. Estudio comparativo de la cultura organizacional

    Directory of Open Access Journals (Sweden)

    Góngora, Norberto H.

    2014-12-01

    Full Text Available El presente trabajo da a conocer resultados parciales de la investigación realizada en el marco del proyecto acreditado “Estudio de las Culturas Organizacionales como determinantes de las personas que trabajan en ellas”, cuyo objetivo general es corroborar las características de cada tipo cultural descriptas en la teoría.Los datos que se exponen son el resultado de varios proyectos de investigación desarrollados utilizando la misma metodología. Se ha obtenido gran cantidad de información para analizar variables asociadas al análisis de la cultura organizacional y así, clasificar cada caso en un tipo cultural. Luego, a partir de la base de datos obtenida se han comparado los datos con las características que describe la teoría, a fin de verificarlos o ponerlos en discusión.La conclusión más importante es que la cultura incide en múltiples aspectos de las conductas de las personas y muchos fenómenos, entre ellos los estudiados en este trabajo, así lo demuestran. Es fundamental estudiar este aspecto de las organizaciones en profundidad y no sólo clasificarlas en uno u otro tipo cultural, ya que existen relaciones entre variables que brindan mayor información que resulta relevante para comprender el comportamiento de las personas.

  3. Un estudio sobre ortografía

    Directory of Open Access Journals (Sweden)

    Maria del Pino LECUONA NARANJO

    2009-11-01

    Full Text Available La dificultad de los escolares en el aprendizaje de la ortografía continúa siendo una preocupación para los profesionales de la educación. Una rápida valoración de los resultados didácticos de esta disciplina en nuestros centros de enseñanza demostraría el bajo rendimiento que en ella manifiestan los discentes. Esta desalentadora realidad fue la que me llevó a tomar este problema como objeto de estudio en un intento de clarificar los factores que de alguna forma pueden condicionar el mal aprendizaje, así como a analizar los aspectos del lenguaje escrito que suponen un mayor conflicto para su correcta ejecución. Porque la importancia de este aspecto de la enseñanza no ha suscitado en España, y especialmente en las últimas décadas, todo el esfuerzo que hubiera requerido para su resolución por parte de los investigadores.

  4. Estudio electrofisiologico en la neuropatia por Vincristina

    Directory of Open Access Journals (Sweden)

    Olga P. Sanz

    1975-12-01

    Full Text Available Diez pacientes afectados por diversas patologías que requerían tratamiento crónico con Vincristina, fueron sometidos a estudios electrofisiológicos en los que se valoró: el número de unidades motoras (UM funcionantes en los músculos de la eminencia tenar, los valores de los incrementos medios de UM, velocidad de conducción motora y su latencia residual en el nervio mediano, la velocidad de conducción sensitiva del mismo nervio y el estado de la transmisión neuromuscular. Los valores obtenidos fueron comparados con grupos controles. Los resultados mostraron disminución del número de UM; las UM remanentes presentaron amplitud reducida junto a otras cuyo tamaño no superaba el del grupo control, hecho que sugiere la incapacidad de lograr una reinervación adecuada. Las velocidades de conducción motora y sensitiva mostraron valores diminuídos, con mayor compromiso en los segmentos distales. Junto a estos datos se halló respuesta miasteniforme al estímulo repetitivo. Todos estos resultados permiten postular la existencia de un compromiso de la unidad motora, abarcando todos sus segmentos, en pacientes intoxicados con Vincristina.

  5. Un estudio de resentimiento en ancianos institucionalizados

    Directory of Open Access Journals (Sweden)

    Dante Gazzolo D.

    1987-06-01

    Full Text Available El presente estudio es una investigación realizada por los Servicios de Psicología del Instituto Nacional de Salud Mental "Honorio Delgado - Hideyo Noguchi", y del Hogar "lgnacia Rodulfa V da. de Canevaro", a través del cual se intenta un acercamiento al devenir psicológico del anciano institucionalizado. Este, al residir permanentemente al interior de un asilo, manifiesta sentimientos de frustración, fracaso y resentimiento, entre otros. Se intenta determinar el grado de: resentimiento que se hace presente en ancianos institucionalizados, tomando en cuenta variables diferenciadoras como condición de vivienda (nivel socio-económico, sexo, edad, estado civil, grado de instrucción, actividad laboral, presencia  o ausencia de hijos, y tiempo de residencia en el asilo.Para tal fin, se evaluó a una muestra de 53  ancianos, 32 mujeres y 21 hombres, 18 de nivel socio-económico alto, y 35 de nivel socio-económico bajo, a través de un Inventario de Actitudes hacia la Vida, encontrando que los sujetos de nivel socio-económico bajo presentan mayores grados de resentimiento que los sujetos de nivel socio-económico alto, observándose, de otro lado, mayores niveles de resentimiento en el sexo masculino que en el femenino.

  6. Anorexia nervosa: un estudio de casos

    Directory of Open Access Journals (Sweden)

    Lillyana Zusman Tinman

    2013-09-01

    Full Text Available La Anorexia Nervosa es un trastorno de alimentación que se define (etimológicamente como una "pérdida nerviosa del apetito". Se caracteriza por la actitud consciente, voluntaria y rotunda de los sujetos  de tener un exceso de peso que intentan modificar por vía de la inanición. A partir del estudio de casos, se propone la distinción entre una Anorexia Nervosa Estructural -aquella en la que predomina el conflicto intrapsíquico primario y arcaico, y que manifiesta una conducta aislada y retraída- y una Anorexia Nervosa Reactiva, aquella en la que predomina un conflicto intrafamiliar algo más posterior y, por lo tanto, una personalidad más abierta y compatible con el medio. Anorexia Nervosa is an Eating Disorder defined (etimoligacally as a "nervouse loss of apetite". It is characterized by a conscious, voluntary and categoric attitude of the sick patient to refrain from eating. He/she has a firm conviction of having excess weight which they try to modify by starvation. Through a case study, a distinction between two types of Anorexia Nervosa is proposed: a Structural Anorexia Nervosa -in which an intrapsyhic, primary, arcaic conflic prevails, leading to an isolated, withdrawal conduct- and a Reactive Anorexia Nervosa, in which a later intrafamilial conflict prevails leading, therefore, to a more open personality, compatible with the enviroment.

  7. Bacteria and vampirism in cinema.

    Science.gov (United States)

    Castel, O; Bourry, A; Thévenot, S; Burucoa, C

    2013-09-01

    A vampire is a non-dead and non-alive chimerical creature, which, according to various folklores and popular superstitions, feeds on blood of the living to draw vital force. Vampires do not reproduce by copulation, but by bite. Vampirism is thus similar to a contagious disease contracted by intravascular inoculation with a suspected microbial origin. In several vampire films, two real bacteria were staged, better integrated than others in popular imagination: Yersinia pestis and Treponema pallidum. Bacillus vampiris was created for science-fiction. These films are attempts to better define humans through one of their greatest fears: infectious disease. PMID:23916557

  8. Turning Bacteria Suspensions into Superfluids

    Science.gov (United States)

    López, Héctor Matías; Gachelin, Jérémie; Douarche, Carine; Auradou, Harold; Clément, Eric

    2015-07-01

    The rheological response under simple shear of an active suspension of Escherichia coli is determined in a large range of shear rates and concentrations. The effective viscosity and the time scales characterizing the bacterial organization under shear are obtained. In the dilute regime, we bring evidence for a low-shear Newtonian plateau characterized by a shear viscosity decreasing with concentration. In the semidilute regime, for particularly active bacteria, the suspension displays a "superfluidlike" transition where the viscous resistance to shear vanishes, thus showing that, macroscopically, the activity of pusher swimmers organized by shear is able to fully overcome the dissipative effects due to viscous loss.

  9. Estudio sobre la efectividad de los editores de partituras y el instrumento, en el estudio de la lectura musical cantada

    OpenAIRE

    Galera N????ez, Mar

    2016-01-01

    Se realiza un estudio en el que se trata de evaluar qu?? medio (instrumento o editor) es el m??s efectivo para enfrentarse al estudio de partituras que han de ser posteriormente interpretadas vocalmente. El estudio se realiz?? con una muestra de 11 alumnos del grado de Maestro en Educaci??n Primaria que cursaban la menci??n de Educaci??n Musical. Los alumnos pose??an diferentes conocimientos previos sobre lectoescritura musical y deb??an enfrentarse a partituras de dos niveles diferentes de d...

  10. Los estudios sobre paisaje en Estudios Geográficos (1940-2009)

    OpenAIRE

    Arroyo Ilera, Fernando; Martín Lou, Mª Asunción

    2010-01-01

    Not available.Los doscientos sesenta y nueve números editados de esta revista son un excelente banco de pruebas donde observar la evolución y los cambios experimentados por la Geografía española, en los últimos setenta años en los que Estudios Geográficos (EG) se viene publicando ininterrumpidamente. La sucesión de temas, su tratamiento y enfoque, las citas bibliográficas, etc., constituyen una excelente referencia de gran interés para cualquier ciencia y, en especial para la nuestra, que ya ...

  11. Conociendo el proceso de estudio en la Facultad de Estudios en Ambientes Virtuales

    OpenAIRE

    2013-01-01

    En el video encuentra información sobre el modelo de enseñanza que utiliza la Facultad de Estudios en Ambientes Virtuales, donde el estudiante es el protagonista de su propio proceso de aprendizaje, utilizando estrategias de aprendizaje autónomo que contribuyen a su adecuada formación consultando el aula, las guías preparadas por la universidad, y utilizando el plan de medio y consultando el material complementario. Participar en todas las actividades que son asignadas, así como el calendario...

  12. El estudio de la cadena productiva del fique

    Directory of Open Access Journals (Sweden)

    Maria Eugenia Morales Rubiano

    2002-09-01

    Full Text Available El estudio recopila los resultados más importantes obtenidos en el trabajo de grado denominado "Estudio de factibilidad de la cadena productiva del fique cultivado en Colombia", el cual tomo como punto de referencia el sector fiquero para estimas la factibilidad de aplicar un esquema de cadena productiva, a través de la estructura y análisis estratégico del sistema.

  13. DMTB: the magnetotactic bacteria database

    Science.gov (United States)

    Pan, Y.; Lin, W.

    2012-12-01

    Magnetotactic bacteria (MTB) are of interest in biogeomagnetism, rock magnetism, microbiology, biomineralization, and advanced magnetic materials because of their ability to synthesize highly ordered intracellular nano-sized magnetic minerals, magnetite or greigite. Great strides for MTB studies have been made in the past few decades. More than 600 articles concerning MTB have been published. These rapidly growing data are stimulating cross disciplinary studies in such field as biogeomagnetism. We have compiled the first online database for MTB, i.e., Database of Magnestotactic Bacteria (DMTB, http://database.biomnsl.com). It contains useful information of 16S rRNA gene sequences, oligonucleotides, and magnetic properties of MTB, and corresponding ecological metadata of sampling sites. The 16S rRNA gene sequences are collected from the GenBank database, while all other data are collected from the scientific literature. Rock magnetic properties for both uncultivated and cultivated MTB species are also included. In the DMTB database, data are accessible through four main interfaces: Site Sort, Phylo Sort, Oligonucleotides, and Magnetic Properties. References in each entry serve as links to specific pages within public databases. The online comprehensive DMTB will provide a very useful data resource for researchers from various disciplines, e.g., microbiology, rock magnetism and paleomagnetism, biogeomagnetism, magnetic material sciences and others.

  14. Los microorganismos en la digestión anaerobia y la producción de biogás. Consideraciones en la elección del inóculo para el mejoramiento de la calidad y el rendimiento

    Directory of Open Access Journals (Sweden)

    Yoandy Ferrer

    2010-01-01

    Se enumeran y explican brevemente los diferentes métodos de aislamiento e identificación establecidos para un estudio taxonómico polifásico, que permita obtener cepas autóctonas de ambientes naturales o fermentadores, a fin de propiciar el diseño de tecnologías que consideren un escalado de inóculo con los microorganismos de mejores rendimientos en la degradación de materiales residuales y alta producción de metano.

  15. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2008-01-01

    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB). They...... utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms in...... other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative of the...

  16. Transformation of gram positive bacteria by sonoporation

    Science.gov (United States)

    Yang, Yunfeng; Li, Yongchao

    2014-03-11

    The present invention provides a sonoporation-based method that can be universally applied for delivery of compounds into Gram positive bacteria. Gram positive bacteria which can be transformed by sonoporation include, for example, Bacillus, Streptococcus, Acetobacterium, and Clostridium. Compounds which can be delivered into Gram positive bacteria via sonoporation include nucleic acids (DNA or RNA), proteins, lipids, carbohydrates, viruses, small organic and inorganic molecules, and nano-particles.

  17. Mortality of fecal bacteria in seawater.

    OpenAIRE

    Garcia-Lara, J.; Menon, P.; Servais, P; Billen, G.

    1991-01-01

    We propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloroacetic acid-insoluble fraction in water samples to which [3H]thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, we found that the actual rate of disappearance of fecal bacteria was 1 ...

  18. Utilization of xylooligosaccharides by selected ruminal bacteria.

    OpenAIRE

    Cotta, M A

    1993-01-01

    The ability of ruminal bacteria to utilize xylooligosaccharides was examined. Xylooligosaccharides were prepared by partially hydrolyzing oat spelt xylan in phosphoric acid. This substrate solution was added (0.2%, wt/vol) to a complex medium containing yeast extract and Trypticase that was inoculated with individual species of ruminal bacteria, and growth and utilization were monitored over time. All of the xylanolytic bacteria examined were able to utilize this oligosaccharide mixture as a ...

  19. QUANTATITIVE PCR ASSAY FOR MARINE BACTERIA

    OpenAIRE

    Brunk, Clifford F.

    2003-01-01

    Monitoring the bacterial flora in coastal marine waters by conventional techniques has been difficult as most of the bacteria do not readily grow on culture plates and their morphologies are virtually identical in the microscope. Molecular techniques, particularly characterizing bacteria using polymerase chain reaction (PCR) amplification of their small subunit ribosomal RNA (SSU rRNA) genes, has dramatically improved the ability to identify bacteria from environmental samples. Identificatio...

  20. Selection-Driven Gene Loss in Bacteria

    OpenAIRE

    Koskiniemi, Sanna; Sun, Song; Berg, Otto; Andersson, Dan I.

    2012-01-01

    Gene loss by deletion is a common evolutionary process in bacteria, as exemplified by bacteria with small genomes that have evolved from bacteria with larger genomes by reductive processes. The driving force(s) for genome reduction remains unclear, and here we examined the hypothesis that gene loss is selected because carriage of superfluous genes confers a fitness cost to the bacterium. In the bacterium Salmonella enterica, we measured deletion rates at 11 chromosomal positions and the fitne...

  1. Pathogenic bacteria and timing of laying

    OpenAIRE

    Moller, Anders P.; Soler, Juan J; Nielsen, J T; Galván, Ismael

    2015-01-01

    Pathogenic bacteria constitute a serious threat to viability of many organisms. Because growth of most bacteria is favored by humid and warm environmental conditions, earlier reproducers in seasonal environments should suffer less from the negative consequences of pathogenic bacteria. These relationships, and the effects on reproductive success, should be particularly prominent in predators because they are frequently exposed to pathogenic microorganisms from sick prey. Here, we presented and...

  2. Bacteria cell properties and grain size impact on bacteria transport and deposition in porous media.

    Science.gov (United States)

    Bai, Hongjuan; Cochet, Nelly; Pauss, André; Lamy, Edvina

    2016-03-01

    The simultaneous role of bacteria cell properties and porous media grain size on bacteria transport and deposition behavior was investigated in this study. Transport column experiments and numerical HYDRUS-1D simulations of three bacteria with different cell properties (Escherichia coli, Klebsiella oxytoca, and Rhodococcus rhodochrous) were carried out on two sandy media with different grain sizes, under saturated steady state flow conditions. Each bacterium was characterized by cell size and shape, cell motility, electrophoretic mobility, zeta potential, hydrophobicity and potential of interaction with the sand surface. Cell characteristics affected bacteria transport behavior in the fine sand, but similar bacteria breakthroughs and retardation factors observed in the coarse sand, indicated that bacteria transport was more depended on grain size than on bacteria cell properties. Retention decreased with increasing hydrophobicity and increased with increasing electrophoretic mobility of bacteria for both sand. The increasing sand grain size resulted in a decrease of bacteria retention, except for the motile E. coli, indicating that retention of this strain was more dependent on cell motility than on the sand grain size. Bacteria deposition coefficients obtained from numerical simulations of the retention profiles indicated that straining was an important mechanism affecting bacteria deposition of E. coli and Klebsiella sp., in the fine sand, but the attachment had the same importance as straining for R. rhodochrous. The results obtained in the coarse sand did not permit to discriminate the predominant mechanism of bacteria deposition and the relative implication of bacteria cell properties of this process. PMID:26705829

  3. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Høiby, N.; Givskov, Michael Christian

    2004-01-01

    Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment and...

  4. In vitro susceptibility testing of anaerobic bacteria.

    Science.gov (United States)

    Washington, J A

    1979-01-01

    In vitro susceptibility testing of anaerobic bacteria should be limited to isolates from persistent or recurrent infections that have been treated adequately and appropriately with antimicrobial agents and, in reference centers, to collections of isolates in order to monitor alterations in susceptibility of species to various antimicrobial agents. An agar dilution reference method is being evaluated currently; however, practicality limits sporadic testing of single isolates to disk elution or broth dilution techniques. No single disk diffusion method has yet been found to be acceptable for testing anaerobic bacteria, and the results obtained with standardized procedures for aerobic and facultatively anaerobic bacteria are not applicable to anaerobic bacteria. PMID:288163

  5. Cell Size Regulation in Bacteria

    Science.gov (United States)

    Amir, Ariel

    2014-05-01

    Various bacteria such as the canonical gram negative Escherichia coli or the well-studied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and interdivision time distributions, as well as the correlations between these variables. We suggest ways of extracting the model parameters from experimental data, and show that existing data for E. coli supports partial size control, and a particular explanation: a cell attempts to add a constant volume from the time of initiation of DNA replication to the next initiation event. This hypothesis accounts for the experimentally observed correlations between mother and daughter cells as well as the exponential dependence of size on growth rate.

  6. Single Bacteria as Turing Machines

    Science.gov (United States)

    Bos, Julia; Zang, Qiucen; Vyawahare, Saurabh; Austin, Robert

    2014-03-01

    In Allan Turing's famous 1950 paper on Computing Machinery and Intelligence, he started with the provocative statement: ``I propose to consider the question, `Can machines think?' This should begin with definitions of the meaning of the terms `machine' and `think'.'' In our own work on exploring the way that organisms respond to stress and evolve, it seems at times as if they come to remarkably fast solutions to problems, indicating some sort of very clever computational machinery. I'll discuss how it would appear that bacteria can indeed create a form of a Turing Machine, the first example of a computer, and how they might use this algorithm to do rapid evolution to solve a genomics problem.

  7. Sterol synthesis in diverse bacteria

    Directory of Open Access Journals (Sweden)

    Jeremy H Wei

    2016-06-01

    Full Text Available Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively. Sterols are also recognized as the diagenetic precursors of steranes preserved in sedimentary rocks where they can function as geological proxies for eukaryotic organisms and/or aerobic metabolisms and environments. However, production of these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize sterols. Phylogenomic studies have identified genes encoding homologs of sterol biosynthesis proteins in the genomes of several additional species, indicating that sterol production may be more widespread in the bacterial domain than previously thought. Although the occurrence of sterol synthesis genes in a genome indicates the potential for sterol production, it provides neither conclusive evidence of sterol synthesis nor information about the composition and abundance of basic and modified sterols that are actually being produced. Here, we coupled bioinformatics with lipid analyses to investigate the scope of bacterial sterol production. We identified oxidosqualene cyclase (Osc, which catalyzes the initial cyclization of oxidosqualene to the basic sterol structure, in 34 bacterial genomes from 5 phyla (Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria and Verrucomicrobia and in 176 metagenomes. Our data indicate that bacterial sterol synthesis likely occurs in diverse organisms and environments and also provides evidence that there are as yet uncultured groups of bacterial sterol producers. Phylogenetic analysis of bacterial and eukaryotic Osc sequences confirmed a complex evolutionary history of sterol synthesis in this domain. Finally, we characterized the lipids produced by Osc-containing bacteria and found that we could generally predict the ability to synthesize sterols. However, predicting the final modified sterol based on our current knowledge of sterol synthesis was difficult

  8. Endophytic Bacteria from Pinus taeda L. as Biocontrol Agents of Fusarium circinatum Nirenberg & O'Donnell Bacterias Endófitas de Pinus taeda L. como Agentes de control Biológico de Fusarium circinatum Nirenberg & O'Donnell

    Directory of Open Access Journals (Sweden)

    Silvina Soria

    2012-06-01

    medio de cultivo donde se hizo crecer el patógeno. En este estudio todas las bacterias mostraron un efecto antagónico sobre el crecimiento del patógeno, deteniéndose el avance del micelio a 1 cm del borde de la colonia bacteriana. Los metabolitos termoestables de las bacterias produjeron una disminución significativa en la tasa de crecimiento del hongo mayor al 50%. Estos resultados muestran que las bacterias que viven dentro de los tejidos sanos del hospedante son una buena alternativa para el control del patógeno F. circinatum en plántulas de Pinus.

  9. Progress in Research of Bacteria Fertilizer Strengthening Resistance of Plants

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Bacteria fertilizer is used most widely among all kinds of microbial fertilizers. We summarize the research headway of bacteria fertilizer. It mainly focuses on bacteria fertilizer improving the stress resistance of plant. Then we can offer basis to research and exploit bacteria fertilizer. These bacteria include azotobacter, photosynthetic bacteria, Bacillus mucilaginosus siliceous, phosphorus bacteria, plant growth-promoting rhizobacteria(PGPR), effective microorganism(EM).

  10. Sponge-associated bacteria: general overview and special aspects of bacteria associated with Halichondria panicea.

    Science.gov (United States)

    Imhoff, J F; Stöhr, R

    2003-01-01

    Increasing evidence is accumulating that highlights the important role of bacteria in bacteria-sponge associations. It appears to be equally important to analyse the specific association of bacteria with sponges, to realise the biological function of biologically active substances produced by sponge-associated bacteria, and to consider the relationship between bacteria and sponges in the search for new pharmaceutical products. In this chapter the current knowledge on bacteria-sponge associations is briefly reviewed. Results are summarised that were obtained by three major methodological approaches: (1) classical microscope observations, (2) investigations attempting to characterise sponge-associated bacteria by describing pure culture isolates, and (3) the rapidly growing evidence from genetic analyses of sponge-associated bacteria. Special emphasis is given to the evidence of possible symbiotic interactions between bacteria and sponges and to the synthesis of natural products by bacteria isolated from or associated with marine sponges. Case studies including morphological and genetic studies together with results from pure culture studies have been performed with bacteria from the sponges Rhodopaloeides odorabile, Aplysina cavernicola, and Halichondria panicea. In addition, new results on bacteria associated with Halichondria panicea are also presented. PMID:15825639

  11. Los estudios sobre paisaje en Estudios Geográficos (1940-2009

    Directory of Open Access Journals (Sweden)

    Arroyo Ilera, Fernando

    2010-12-01

    Full Text Available Not available.Los doscientos sesenta y nueve números editados de esta revista son un excelente banco de pruebas donde observar la evolución y los cambios experimentados por la Geografía española, en los últimos setenta años en los que Estudios Geográficos (EG se viene publicando ininterrumpidamente. La sucesión de temas, su tratamiento y enfoque, las citas bibliográficas, etc., constituyen una excelente referencia de gran interés para cualquier ciencia y, en especial para la nuestra, que ya en otras ocasiones ha sido utilizada para valorar la evolución metodológica de la Geografía.

  12. Rapid methods for detection of bacteria

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Andersen, B.Ø.; Miller, M.; Ursin, C.; Arvin, Erik; Albrechtsen, Hans-Jørgen

    Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods...

  13. Lactic Acid Bacteria in the Gut

    NARCIS (Netherlands)

    Stolaki, M.; Vos, de W.M.; Kleerebezem, M.; Zoetendal, E.G.

    2012-01-01

    From all bacterial groups, the lactic acid bacteria (LAB) are probably the group of bacteria that is most associated with human lifestyle. The term LAB mainly refers to the ability of these organisms to convert sugars to lactic acid. The LAB comprise non-sporing, aerotolerant, coccus or rod-shaped,

  14. Sabine Kacunko. Bacteria, Art and other Bagatelles

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    This book appears on the occasion of the project INVINCIBLE – a Big Bacteria project for Colosseum, Rome (17.–19.09.2015), which is being granted UNESCO-patronage in the context of the International Year of Light and Light-Based Technologies 2015. With Sabine Kacunko’s bacteria art in mind, alleged...

  15. Rapid methods for detection of bacteria

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Andersen, B.Ø.; Miller, M.;

    2006-01-01

    Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods...

  16. Metabolismo de isoflavonas por bacterias intestinales

    OpenAIRE

    Delgado, Susana; Guadamuro, Lucía; Flórez García, Ana Belén; Mayo Pérez, Baltasar

    2014-01-01

    Trabajo presentado en la 8ª Reunión de la Red Temática BAL (Red Española de Bacterias Lácticas), "Participación de las Bacterias Lácticas en la Salud Humana y en la Calidad Alimentaria", celebrada en San Adrián (Navarra) el 25 de junio de 2014.

  17. Bacteria dispersal by hitchhiking on zooplankton

    DEFF Research Database (Denmark)

    Grossart, Hans-Peter; Dziallas, Claudia; Leunert, Franziska;

    2010-01-01

    impenetrable for bacteria in both upward and downward directions (conveyor-belt hypothesis). The strength of our experiments is to permit quantitative estimation of transport and release of associated bacteria: vertical migration of Daphnia magna yielded an average dispersal rate of 1.3 x 10(5) x cells x...

  18. Research Advances in Bacteria-based Microrobot.

    Science.gov (United States)

    Liang, Yao-Jie; Sun, Jun-Zhong

    2016-08-01

    The concept of bacteria-based microrobot has been well recognized. It has shown great advantages and potentials for the early diagnosis and early treatment of malignant tumor and in reducing chemotherapy toxicities. In this article we review the concept,structure,and potential clinical applications of bacteria-based microrobot. PMID:27594160

  19. Comparative genomics of the lactic acid bacteria

    Science.gov (United States)

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacter...

  20. Method of dispersing a hydrocarbon using bacteria

    Science.gov (United States)

    Tyndall, Richard L.

    1996-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  1. Mimicking Seawater For Culturing Marine Bacteria

    DEFF Research Database (Denmark)

    Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone;

    2015-01-01

    Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum as...... solidifying agents, and enumerated bacteria from seawater and algal exudates. We tested if culturability could be influenced by addition of quorum sensing signals (AHLs). All plates were incubated at 15°C. Bacterial counts (CFU/g) from algal exudates from brown algae were highest on media containing algal...... polymers. In general, bacteria isolated from algal exudates preferred more rich media than bacteria isolated from seawater. Overall, culturability ranged from 0.01 to 0.8% as compared to total cell count. Substitution of agar with gellan gum increased the culturability of seawater bacteria approximately...

  2. Coryneform bacteria associated with canine otitis externa

    DEFF Research Database (Denmark)

    Aalbæk, Bent; Bemis, David A.; Schjærff, Mette;

    2010-01-01

    This study aims to investigate the occurrence of coryneform bacteria in canine otitis externa. A combined case series and case-control study was carried out to improve the current knowledge on frequency and clinical significance of coryneform bacteria in samples from canine otitis externa. A total...... of 16 cases of otitis externa with involvement of coryneform bacteria were recorded at two referral veterinary hospitals in Denmark and the US, respectively. Coryneform bacteria were identified by partial 16S rRNA gene sequencing. Corynebacterium auriscanis was the most common coryneform species (10...... cases). Small colony variants of this species were also observed. Other coryneform isolates were identified as Corynebacterium amycolatum (3 cases), Corynebacterium freneyi (2 cases) and an Arcanobacterium-like species (1 case). The coryneform bacteria were in all cases isolated together with other...

  3. Chryseobacterium indologenes, novel mannanase-producing bacteria

    Directory of Open Access Journals (Sweden)

    Surachai Rattanasuk

    2009-10-01

    Full Text Available Mannanase is a mannan degrading enzyme which is produced by microorganisms, including bacteria. This enzyme can be used in many industrial processes as well as for improving the quality of animal feeds. The aim of the present study was toscreen and characterize the mannanase-producing bacteria. Two genera of bacteria were isolated from Thai soil samples,fermented coconut, and fertilizer. Screening was carried out on agar plates containing mannan stained with iodine solution.The bacteria were identified by partial 16S rRNA gene sequence, biochemical test and morphology, respectively. The mannanase activity was determined by zymogram and DNS method. Two strains of bacteria with mannanase activity were identified as Bacillus and Chryseobacterium. This is the first report of mannanase-producing Chryseobacterium.

  4. HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

    2006-08-15

    Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

  5. Obtención de un mejorador de suelos como subproducto de la digestión anaerobia de desechos orgánicos en el TEC Obtention of a soil improver as subproduct from the anaerobic digestion of organic residues at the Technological Institute of Costa Rica

    OpenAIRE

    Margie Faith Vargas; Olga Rivas Solano

    2012-01-01

    El tratamiento anaerobio de los desechos orgánicos permite obtener efluentes con propiedades biofertilizantes, además de biogás para la generación de energía renovable. El objetivo del presente estudio fue evaluar una mezcla de los efluentes de dos biodigestores a escala en elTEC para determinar su potencial uso como bioabono. Se analizó la composición química y se encontró que el proceso de biodigestión aumentó el contenido de nutrientes. Se determinó la calidad microbiológica y se observó u...

  6. Inmunodeficiencias humorales: Un estudio en tres Centros de Inmunología Clínica de adultos en la Ciudad de Buenos Aires

    Directory of Open Access Journals (Sweden)

    Diego S. Fernández Romero

    2011-08-01

    Full Text Available Las inmunodeficiencias humorales (IDH comprenden a un grupo de enfermedades caracterizadas por la imposibilidad de desarrollar una respuesta inmune efectiva mediada por anticuerpos. Estos pacientes presentan infecciones, principalmente por bacterias extracelulares capsuladas, del tracto respiratorio. El objetivo de nuestro estudio fue describir las características clínicas de una población de 128 pacientes derivados con sospecha o diagnóstico de IDH a tres centros para inmunodeficiencias de adultos, asistidos entre junio de 2004 y diciembre de 2009. Tres (2.3% consultaron por infecciones recurrentes en una sola oportunidad sin datos suficientes para su adecuada clasificación y fueron excluidos del estudio. De los 125 pacientes restantes, en 21 (16.8% se descartó IDH, en 8 (6.4% se diagnosticó inmunodeficiencia humoral secundaria (IDHS y en 96 (76.8% inmunodeficiencia humoral primaria (IDHP. Las causas de IDHS fueron: en un caso enfermedad renal, en uno uso de fenitoína, dos casos: gammapatía monoclonal y en 4 linfoma B. Las causas de las 96 IDHP fueron: 57 inmunodeficiencia común variable, 12 agammaglobulinemia ligada al cromosoma X, 10 deficiencia selectiva de IgA, 7 deficiencia de IgG1, 3 síndrome hiper-IgM, 3 deficiencia de IgM, 2 síndrome linfoproliferativo ligado al cromosoma X, un síndrome de Good y una deficiencia funcional de anticuerpos. Sesenta y siete pacientes estaban en seguimiento en el momento de la finalización del estudio, 25 de ellos estaban en seguimiento al iniciarse el estudio. De los 58 pacientes en seguimiento con indicación de tratamiento sustitutivo con gammaglobulina, 54 se encontraban en tratamiento al finalizar el estudio. En cuatro pacientes no se pudo confirmar el diagnóstico de IDHP.

  7. Therapeutic Properties of Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Nathanon Trachoo

    2006-01-01

    Full Text Available In spite of its long history, public consciousness of probiotics has shifted dramatically in recent years. This is due to a number of factors, including an increased concern about the potential generation of antibiotic resistant bacterial strains due to widespread antibacterial use, and also to the spreading realization that one`s health can be, not simply maintained, but actually improved with proper nutrition. Combined, these factors have stimulated a surge in probiotic research in the past decade, resulting in increasingly refined studies. Indeed, after Elie Metchnikov first printed his work suggesting a positive correlation between human longevity and the consumption of fermented milk, information on probiotics is leaving the realm of the anecdotal as recent, double-blind, placebo controlled randomized tests support beneficial probiotic activity. Concurrently, more is being learned about their activities in vivo. While much work remains to be done before a detailed understanding of probiotics can be achieved, there is mounting evidence that probiotics, when used in proper conditions, may indeed have prophylactic or preventative effects on a broad array of human and animal diseases. This article briefly surveys probiotic history and discusses recent research with a special emphasis on lactic acid bacteria probiotics. Finally, it discusses the inherent difficulties of their study and suggestions for standards for future work.

  8. Mycelial bacteria of saline soils

    Science.gov (United States)

    Zvyagintsev, D. G.; Zenova, G. M.; Oborotov, G. V.

    2008-10-01

    The actinomycetal complexes of saline soils comprise the representatives of the Streptomyces and Micromonospora genera, the number of which are hundreds and thousands of CFU/g soil. Complexes of mycelial bacteria in saline soils are poorer in terms of number (by 1-3 orders of magnitude) and taxonomic composition than the complexes of the zonal soil types. A specific feature of the actinomycetal complexes of saline soils is the predominance of halophilic, alkaliphilic, and haloalkaliphilic streptomycetes that well grow at pH 8-9 and concentrations of NaCl close to 5%. Actinomycetes in saline soils grow actively, and the length of their mycelium reaches 140 m in 1 gram of soil. The haloalkaliphilic streptomycetes grow fast and inhibit the formation of spores at pH 9 and high concentrations of salts (Na2SO4 and MgCl2, 5%) as compared to their behavior on a neutral medium with a salt concentration of 0.02%. They are characterized by the maximal radial growth rate of colonies on an alkaline medium with 5% NaCl.

  9. Comparative cytotoxicity of periodontal bacteria

    International Nuclear Information System (INIS)

    The direct cytotoxicity of sonic extracts (SE) from nine periodontal bacteria for human gingival fibroblasts (HGF) was compared. Equivalent dosages (in terms of protein concentration) of SE were used to challenge HGF cultures. The cytotoxic potential of each SE was assessed by its ability to (1) inhibit HGF proliferation, as measured by direct cell counts; (2) inhibit 3H-thymidine incorporation in HGF cultures; or (3) cause morphological alterations of the cells in challenged cultures. The highest concentration (500 micrograms SE protein/ml) of any of the SEs used to challenge the cells was found to be markedly inhibitory to the HGFs by all three of the criteria of cytotoxicity. At the lowest dosage tested (50 micrograms SE protein/ml); only SE from Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Fusobacterium nucleatum caused a significant effect (greater than 90% inhibition or overt morphological abnormalities) in the HGFs as determined by any of the criteria employed. SE from Capnocytophaga sputigena, Eikenella corrodens, or Wolinella recta also inhibited cell proliferation and thymidine incorporation at this dosage; however, the degree of inhibition (5-50%) was consistently, clearly less than that of the first group of three organisms named above. The SE of the three other organisms tested (Actinomyces odontolyticus, Bacteroides intermedius, and Streptococcus sanguis) had little or no effect (0-10% inhibition) at this concentration. The data suggest that the outcome of the interaction between bacterial components and normal resident cells of the periodontium is, at least in part, a function of the bacterial species

  10. H2 from hot bacteria

    International Nuclear Information System (INIS)

    This paper reports that a surprisingly large number of bacteria either oxidize or evolve molecular hydrogen (H2) in their natural environments. In such organisms, the reversible activation of H2 is catalyzed by an enzyme turned hydrogenase that can cause electrons provided by an electron donor with protons to evolve H2. The enzyme may oxidize H2 in the presence of a suitable electron acceptor. Hydrogenase will also catalyze an isotope exchange reaction between deuterium (D2) or tritium (T2) gas and water. Few enzymes have as many potential biotechnological applications as hydrogenase. H2 is a versatile and efficient energy carrier, considered the fuel of the future by some, and is an important intermediate in a variety of chemical and petrochemical processes. Hydrogenase has also been proposed to replace platinum in H/D and H/T separations in the nuclear power industry and to activate H2 for electrode-based processes. Indeed, H2 is considered one of the most abundant substrates for the future chemical synthesis industry and the enzyme-catalyzed production of organic chemicals from H2 and CO2 has been described. a complete understanding of how hydrogenases catalyze the reversible activation of H2 might therefore have farreaching consequences in both applied and basic research

  11. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Alix M Denoncourt

    2014-05-01

    Full Text Available Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.

  12. Detección de bacterias fitopatógenas en semillas de maíz (zea mays L.)

    OpenAIRE

    Yonis Hernández; Gustavo Trujillo

    2001-01-01

    Se realizó un estudio con el objeto de conocer la presencia de bacterias fitopatógenas en semillas de maíz. Las muestras de este cereal, que es uno de los más importantes cultivos agrícolas en el ámbito mundial y uno de los primeros en Venezuela, fueron recolectadas en el Centro Nacional de Investigaciones Agropecuarias y la Universidad Central de Venezuela, y se analizaron usando serología (doble difusión en agar) y medio semiselectivo. De 21 muestras de maíz dentado, todas resultaron contam...

  13. Estudio acústico del Conservatorio de Piles

    OpenAIRE

    VILLA MORANT, SARA

    2014-01-01

    El objetivo de este proyecto es realizar un estudio acústico general de la "Casa de la Cultura" de Piles, sobre todo de los recintos que más lo requieren, como la sala principal de música. El edificio, al tratarse de una construcción antigua, no reúne las especificaciones acústicas establecidas en el Código Técnico vigente en la actualidad. En primer lugar, se realiza el estudio del acondicionamiento acústico de la sala principal, entendiéndose como acondicionamiento acústico la definición de...

  14. Trastornos de personalidad y edad: Estudio con personas sin hogar

    OpenAIRE

    Salavera, Carlos; Puyuelo, Miguel; Orejudo Hernández, Santos

    2009-01-01

    En este estudio se lleva a cabo una investigación sobre trastor-nos de personalidad en personas sin hogar y su relación con la edad. El objetivo era analizar si existe relación entre edad y trastorno de personali-dad padecido por el sujeto. Para ello, se realizó un estudio ex post facto, de carácter prospectivo, con una muestra de personas sin hogar en un proce-so de inserción (N=77) a las que se aplicó una entrevista semiestructurada y el Inventario Clínico Multiaxial de Millon (Millon, 1997...

  15. Estudio radiológico de un cuerpo momificado infantil

    OpenAIRE

    Robledo Acinas, María del Mar; Sánchez Sánchez, José Antonio; Minaya Bernedo, Angel

    2012-01-01

    En este estudio presentamos un cuerpo humano momificado infantil, perteneciente a la colección del Museo de Antropología Médica y Forense, Paleopatología y Criminalística, de la Facultad de Medicina de la Universidad Complutense de Madrid, Reverte (1999). Realizamos estudio macroscópico y radiológico con el objetivo de estimar la edad y posibles patologías que puedan apreciarse, y, a la vista de los resultados obtenidos, podemos concluir que tenía en el momento de su m...

  16. Estudio de Rodilla Flotante en pacientes del Hospital Clinico Viedma

    OpenAIRE

    Omar Marcelo Vargas Fuentes; Omar Manuel Mustafá Millán; Jorge Alberto Fuentes Soliz

    2011-01-01

    Se denomina “Rodilla Flotante” a la combinación de fractura de fémur y tibia ipsilaterales. La incidencia exacta se desconoce, pero tiene un abordaje terapéutico complejo, una alta tasa de complicaciones y una elevada mortalidad.El presente estudio busca determinar los aspectos relacionados con esta patología en nuestro medio y analizarlos de una manera integral, realizándose para esto un estudio descriptivo y longitudinal retrospectivo abarcando 18 meses (de julio 2008 a diciembre 2009) que ...

  17. Generalización en el estudio de funciones lineales

    OpenAIRE

    Flores, Ángel; Chávez, Guadalupe

    2013-01-01

    En este artículo se presentan los avances de una investigación educativa que busca indagar los procesos de generalización de patrones en estudiantes de bachillerato en el Colegio de Ciencias y Humanidades de la UNAM (edades entre 15 y 17 años) y el papel que tales procesos juegan en el estudio de funciones lineales. Se buscó respuesta a la pregunta: ¿Cuál es el grado de entendimiento del concepto de función lineal en estudiantes de primer semestre de Bachillerato cuando su estudio parte de ac...

  18. Estudio de caso y aprendizaje cooperativo en la universidad

    OpenAIRE

    Pedro Aramendi Jauregui; Karmele Bujan Vidales; Segundo Garín Casares; Amando Vega Fuente

    2014-01-01

    Dise??ar los planes de estudio en funci??n del desarrollo de competencias demanda cambios metodol??gicos importantes. El m??todo de caso es una de las estrategias de ense??anza y aprendizaje m??s adecuadas para desarrollar las competencias orientadas al trabajo en equipo y al fomento de la colaboraci??n. El art??culo que se presenta es un resumen del proyecto de innovaci??n ???El estudio de caso y el aprendizaje cooperativo en la universidad??? (PIE-2010-2012) financiado por la Unive...

  19. Estudio y Conservación del Patrimonio Cultural. Actas

    OpenAIRE

    Moreno Oliva, María; Rogerio Candelera, Miguel A.; López Navarrete, Juan T.; Hernández, Víctor

    2015-01-01

    Estudio y Conservación del Patrimonio Cultural recoge cuarenta y nueve ponencias presentadas al Congreso Nacional “Estudio y Conservación del Patrimonio Cultural”, celebrado en Málaga entre los días 16 y 19 de noviembre de 2015. El congreso, organizado por el Nodo “Arqueometría- Raman-UMA” (U38) dentro del marco de la iniciativa TechnoHeritage, continúa la labor de los tres congresos ya celebrados hasta ahora por TechnoHeritage: Congreso Nacional sobre Ciencia y Tecnología para la Conservació...

  20. ESTUDIO DE VIABILIDAD DE UNA CLINICA PRIVADA EN GUINEA ECUATORIAL

    OpenAIRE

    TEN ROLDÁN, CARLOTA

    2012-01-01

    El presente documento contiene un estudio de viabilidad sobre un proyecto consistente en la construcción de una clínica privada en Guinea Ecuatorial, concretamente en la ciudad de Bata, la más poblada del país. Esta idea surge de un propósito real de llevar a cabo dicho proyecto por parte de un inversor nativo de Guinea Ecuatorial.La metodología empleada para llevar a cabo dicha tarea ha sido elaboración de un estudio del entorno, analizando las características demográficas y económicas del p...

  1. Estudio de viabilidad de un mercado en Cunit

    OpenAIRE

    Sayavera Giménez, Alberto; Vicente Barbero, Alexandra

    2010-01-01

    El trabajo que a continuación se expone tiene como objetivo desarrollar el estudio de las variables que determinan la viabilidad de la construcción y explotación de un mercado de producto fresco y ecológico, ubicado en la población de Cunit (Tarragona). La idea de este estudio surge de la carencia que presenta el municipio de Cunit, en cuanto a equipamientos se refiere, debido al inesperado aumento de la población que se produjo entre los años 1.990 y 2.000. Asimismo, el com...

  2. Cepas nativas del bacterioneuston marino y su actividad inhibitoria de bacterias ictiopatógenas

    Directory of Open Access Journals (Sweden)

    Jorge León

    2014-06-01

    Full Text Available En la literatura científica, las bacterias marinas han sido consideradas con frecuencia como productores de sustancias antibacterianas. En este estudio, se investigó el potencial de actividad antibiótica in vitro de cepas nativas de bacterioneuston marino aisladas de las pozas intermareales de Montemar, Bahía de Valparaiso, Chile. Se aislaron 71 cepas neustónicas antagonistas a Staphylococcus aureus ATCC 11632. Veinticinco de ellas, productoras de sustancias fuertemente inhibitorias, fueron evaluadas por su antagonismo frente a una colección de 15 bacterias ictiopatógenas. Aplicando métodos clásicos para bacterias marinas, se caracterizaron fenotípicamente orientados a la identificación. Los resultados de antibiosis indican que la totalidad cle las ictiopatógenas en prueba son susceptibles a la actividad inhibitoria de las cepas neustónicas, siendo V anguillarum NCMB 2133, V ordalii 84/2559 y V tubiashii EX1 las más sensibles. Entre las cepas aisladas del neuston se identificaron miembros de los géneros Vibrio spp. (28%, Flavobacterium spp. (12%, Alteromonas-Marinomonas (12%, Pseudomonas spp (8% y Micrococcus spp, (4%. Nueve cepas (36% no fueron identificadas. Los resultados de actividades inhibitorias frente a ictiopatógenos sugieren que dichas cepas o sus productos pudieran ser útiles en actividades de cultivos intensivos de maricultura de peces, moluscos y crustáceos.

  3. Dinámica de un biorreactor con modelo de crecimiento de bacterias lineal por tramos = Dynamics of a biorreactor with bacterial growth model piecewise linear

    OpenAIRE

    Melo Varela, Luz Alba

    2011-01-01

    El presente trabajo trata sobre la dinámica de un bioreactor UASB (Reactor Anaeróbico de Flujo Ascendente y Manto de Lodos), ubicado en los Laboratorios de Procesos Productivos de la Universidad Nacional de Colombia Sede Manizales. El modelo matemático de degradación de materia orgánica obtenido por Muñoz, 2006 [25] para la digestión anaerobia del reactor UASB, se varia realizando una aproximación por rectas al modelo de crecimiento bacteriano gobernado por la cinética de Monod. Por tanto el ...

  4. Bacteria classification using Cyranose 320 electronic nose

    Directory of Open Access Journals (Sweden)

    Gardner Julian W

    2002-10-01

    Full Text Available Abstract Background An electronic nose (e-nose, the Cyrano Sciences' Cyranose 320, comprising an array of thirty-two polymer carbon black composite sensors has been used to identify six species of bacteria responsible for eye infections when present at a range of concentrations in saline solutions. Readings were taken from the headspace of the samples by manually introducing the portable e-nose system into a sterile glass containing a fixed volume of bacteria in suspension. Gathered data were a very complex mixture of different chemical compounds. Method Linear Principal Component Analysis (PCA method was able to classify four classes of bacteria out of six classes though in reality other two classes were not better evident from PCA analysis and we got 74% classification accuracy from PCA. An innovative data clustering approach was investigated for these bacteria data by combining the 3-dimensional scatter plot, Fuzzy C Means (FCM and Self Organizing Map (SOM network. Using these three data clustering algorithms simultaneously better 'classification' of six eye bacteria classes were represented. Then three supervised classifiers, namely Multi Layer Perceptron (MLP, Probabilistic Neural network (PNN and Radial basis function network (RBF, were used to classify the six bacteria classes. Results A [6 × 1] SOM network gave 96% accuracy for bacteria classification which was best accuracy. A comparative evaluation of the classifiers was conducted for this application. The best results suggest that we are able to predict six classes of bacteria with up to 98% accuracy with the application of the RBF network. Conclusion This type of bacteria data analysis and feature extraction is very difficult. But we can conclude that this combined use of three nonlinear methods can solve the feature extraction problem with very complex data and enhance the performance of Cyranose 320.

  5. Antibacterial activity of aquatic gliding bacteria.

    Science.gov (United States)

    Sangnoi, Yutthapong; Anantapong, Theerasak; Kanjana-Opas, Akkharawit

    2016-01-01

    The study aimed to screen and isolate strains of freshwater aquatic gliding bacteria, and to investigate their antibacterial activity against seven common pathogenic bacteria. Submerged specimens were collected and isolated for aquatic gliding bacteria using four different isolation media (DW, MA, SAP2, and Vy/2). Gliding bacteria identification was performed by 16S rRNA gene sequencing and phylogenetic analysis. Crude extracts were obtained by methanol extraction. Antibacterial activity against seven pathogenic bacteria was examined by agar-well diffusion assay. Five strains of aquatic gliding bacteria including RPD001, RPD008, RPD018, RPD027 and RPD049 were isolated. Each submerged biofilm and plastic specimen provided two isolates of gliding bacteria, whereas plant debris gave only one isolate. Two strains of gliding bacteria were obtained from each DW and Vy/2 isolation medium, while one strain was obtained from the SAP2 medium. Gliding bacteria strains RPD001, RPD008 and RPD018 were identified as Flavobacterium anhuiense with 96, 82 and 96 % similarity, respectively. Strains RPD049 and RPD027 were identified as F. johnsoniae and Lysobacter brunescens, respectively, with similarity equal to 96 %. Only crude extract obtained from RPD001 inhibited growth of Listeria monocytogenes (MIC 150 µg/ml), Staphylococcus aureus (MIC 75 µg/ml) and Vibrio cholerae (MIC 300 µg/ml), but showed weak inhibitory effect on Salmonella typhimurium (MIC > 300 µg/ml). Gliding bacterium strain RPD008 should be considered to a novel genus separate from Flavobacterium due to its low similarity value. Crude extract produced by RPD001 showed potential for development as a broad antibiotic agent. PMID:26885469

  6. Stop the Spread of Superbugs: Help Fight Drug Resistant Bacteria

    Science.gov (United States)

    ... the Spread of Superbugs Help Fight Drug-Resistant Bacteria For nearly a century, bacteria-fighting drugs known as antibiotics have helped to control and destroy many of the harmful bacteria that can make us sick. But in recent ...

  7. Birefringence Determination of Magnetic Moments of Magnetotactic Bacteria

    OpenAIRE

    Rosenblatt, Charles; de Araujo, F. Flavio Torres; Frankel, Richard B.

    1982-01-01

    A birefringence technique is used to determine the average magnetic moments of magnetotactic bacteria in culture. Differences in are noted between live and dead bacteria, as well as between normal density and high density samples of live bacteria.

  8. Folate Production by Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Stefano Raimondi

    2011-01-01

    Full Text Available Probiotic bacteria, mostly belonging to the genera Lactobacillus and Bifidobacterium, confer a number of health benefits to the host, including vitamin production. With the aim to produce folate-enriched fermented products and/or develop probiotic supplements that accomplish folate biosynthesis in vivo within the colon, bifidobacteria and lactobacilli have been extensively studied for their capability to produce this vitamin. On the basis of physiological studies and genome analysis, wild-type lactobacilli cannot synthesize folate, generally require it for growth, and provide a negative contribution to folate levels in fermented dairy products. Lactobacillus plantarum constitutes an exception among lactobacilli, since it is capable of folate production in presence of para-aminobenzoic acid (pABA and deserves to be used in animal trials to validate its ability to produce the vitamin in vivo. On the other hand, several folate-producing strains have been selected within the genus Bifidobacterium, with a great variability in the extent of vitamin released in the medium. Most of them belong to the species B. adolescentis and B. pseudocatenulatum, but few folate producing strains are found in the other species as well. Rats fed a probiotic formulation of folate-producing bifidobacteria exhibited increased plasma folate level, confirming that the vitamin is produced in vivo and absorbed. In a human trial, the same supplement raised folate concentration in feces. The use of folate-producing probiotic strains can be regarded as a new perspective in the specific use of probiotics. They could more efficiently confer protection against inflammation and cancer, both exerting the beneficial effects of probiotics and preventing the folate deficiency that is associated with premalignant changes in the colonic epithelia.

  9. Magnetotactic Bacteria from Extreme Environments

    Science.gov (United States)

    Bazylinski, Dennis A.; Lefèvre, Christopher T.

    2013-01-01

    Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI) in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0. PMID:25369742

  10. Magnetotactic Bacteria from Extreme Environments

    Science.gov (United States)

    Bazylinski, Dennis A.; Lefère, Christopher T.

    2013-03-01

    Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth's geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic-anoxic interface (OAI) in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

  11. Magnetotactic Bacteria from Extreme Environments

    Directory of Open Access Journals (Sweden)

    Christopher T. Lefèvre

    2013-03-01

    Full Text Available Magnetotactic bacteria (MTB represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4 or greigite (Fe3S4 and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

  12. Effects of thermoradiation on bacteria

    International Nuclear Information System (INIS)

    A 60Co source was used to determine the effects of thermoradiation on Achromobacter aquamarinus, Staphylococcus aureus, and vegetative and spore cells of Bacillus subtilis var. globigii. The rate of inactivation of these cultures, except vegetative-cell populations of B. subtilis, was exponential and in direct proportion to temperature. The D10 (dose that inactivates 90 percent of the microbial population) value for A. aquamarinus was 8.0 Krad at 25 degrees C and 4.9 Krad at 35 degrees C. For S. aureus, D10 was 9.8 and 5.3 Krad at 35 and 45 degrees C, respectively. Vegetative cells of B. subtilis demonstrated a rapid initial inactivation followed by a steady but decreased exponential rate. The D10 at 25 degrees C was 10.3 Krad, but at 35 and 45 degrees C this value was 6.2 and 3.8 Krad, respectively. Between 0 and 95 Krad, survival curves for B. subtilis spores at 75 degrees C showed slight inactivation, increasing in rat at and above 85 degrees C. The D10 values for spores at 85 and 90 degrees C were 129 and 92 Krad, respectively. Significant synergism between heat and irradiation was noted at 35 degrees C for A. aquamarinus and 45 degrees C for S. aureus. The presence of 0.1 mM cysteine in suspending media afforded protection to both cultures at these critical temperatures. On the other hand, cysteine sensitized B. subtilis spores at radiation doses greater than 100 Krad. The combined effect of heat and irradiation was more destructive to bacteria than either method alone

  13. Clustering of Marine Bacteria in Seawater Enrichments

    OpenAIRE

    Mitchell, J.G.; Pearson, L; Dillon, S.

    1996-01-01

    Seawater enrichments of marine bacteria clustered in 20- to 50-(mu)m-wide bands near air-water interfaces. The cells within the band travelled at up to 212 (mu)m s(sup-1) and at an average speed of 163 (mu)m s(sup-1). Mean cell speeds peaked mid-run at 187 (mu)m s(sup-1). At the end of the run, bacteria reversed direction rather than randomly reorienting. The duration of the stops during reversal was estimated at 18 ms, six to seven times shorter than that found in enteric bacteria. Cells hun...

  14. The Microworld of Marine-Bacteria

    DEFF Research Database (Denmark)

    JØRGENSEN, BB

    1995-01-01

    Microsensor studies show that the marine environment in the size scale of bacteria is physically and chemically very different from the macroenvironment. The microbial world of the sediment-water interface is thus dominated by water viscosity and steep diffusion gradients. Because of the diverse...... metabolism types, bacteria in the mostly anoxic sea floor play an important role in the major element cycles of the ocean. The communities of giant, filamentous sulfur bacteria that live in the deep-sea hydrothermal vents or along the Pacific coast of South America are presented here as examples....

  15. Acidophilic, Heterotrophic Bacteria of Acidic Mine Waters

    OpenAIRE

    Wichlacz, Paul L.; Unz, Richard F.

    1981-01-01

    Obligately acidophilic, heterotrophic bacteria were isolated both from enrichment cultures developed with acidic mine water and from natural mine drainage. The bacteria were grouped by the ability to utilize a number of organic acids as sole carbon sources. None of the strains were capable of chemolithotrophic growth on inorganic reduced iron and sulfur compounds. All bacteria were rod shaped, gram negative, nonencapsulated, motile, capable of growth at pH 2.6 but not at pH 6.0, catalase and ...

  16. Estudio de centrales de biomasa a pequeña escala como fuente de energía en las zonas rurales de la región de Göttingen (Alemania)

    OpenAIRE

    Veinat Grimalt, Francisca

    2013-01-01

    Las plantas de digestión anaerobia de biomasa se presentan como una buena opción tanto para la valorización económica de purines como para la obtención de energía a partir de fuentes renovables produciendo biogás. Dicha producción se puede mejorar mediante la co-digestión de los purines con cosustratos agrícolas o agroindustriales. A partir de las anteriores premisas se ha desarrollado en la región alemana de Göttingen los denominados pueblos bioenergéticos. Los cuales con recursos locale...

  17. Estudio de la factibilidad para el aprovechamiento de biogás en el Rastro Municipal de Benito Juárez (Cancún. Quintana Roo, México)

    OpenAIRE

    Sánchez Téllez, Trinidad Nohemi

    2014-01-01

    En el presente trabajo se han analizado las características de los residuos generados en el Rastro Municipal de Benito Juárez, así como los factores que intervienen en la digestión anaerobia. El objetivo es determinar la factibilidad de implementar un biodigestor en el Rastro Municipal, el cual permita generar biogás para cubrir los requerimientos de combustible de la instalación y gestionar adecuadamente los residuos generados, subproductos de las operaciones del Rastro. Se han calculado el ...

  18. Reflexiones acerca del estudio de la conducta desviada

    Directory of Open Access Journals (Sweden)

    Raquel Cruz Betancourt

    2005-01-01

    Full Text Available Aborda cuestiones referentes a la definición de la conducta desviada y los diversos aspectos que se han abordado en su estudio, así como criterios sobre el tema vertidos por varios especialistas tanto cubanos como de otras partes del mundo.

  19. Reflexiones acerca del estudio de la conducta desviada

    OpenAIRE

    Raquel Cruz Betancourt

    2005-01-01

    Aborda cuestiones referentes a la definición de la conducta desviada y los diversos aspectos que se han abordado en su estudio, así como criterios sobre el tema vertidos por varios especialistas tanto cubanos como de otras partes del mundo.

  20. Estudio diferenciado de las víctimas

    OpenAIRE

    Ramón Martín, Aitana

    2007-01-01

    Estudio deferenciado de las características de los tipos de VÍCTIMAS en función del delito. Mecanismos de reparación, prevención, medidas asistenciales. Observatorio contra la violencia doméstica y de género (Anexo).

  1. Quorum sensing in Gram-negative bacteria

    Institute of Scientific and Technical Information of China (English)

    WU Hong; SONG Zhijun; Niels HФIBY; Michael GIVSKOV

    2004-01-01

    Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community,and the mechanism is referred to as quorum sensing (QS).Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal molecules.Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread.These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment and particularly higher organisms,covering a variety of functions ranging from pathogenic to symbiotic interactions.The detailed knowledge of these bacterial communication systems has opened completely new perspectives for controlling undesired microbial activities.

  2. Comparative genomics of the lactic acid bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O' Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

    2006-06-01

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

  3. DECONTAMINATION OF HEAVY METALS WITH BACTERIA

    Science.gov (United States)

    OBJECTIVES: To discover, improve, understand the mechanisms and use naturally occurring bacteria to decontiminate in situ heavy metals from the soils, sediments and waters to protect human health and the environment. ABSTRACT: Our laboratory (Vesper et al. ...

  4. Distribution of phytopathogenic bacteria in infested seeds

    Science.gov (United States)

    Populations of phytopathogenic bacteria representing five host-pathogen combinations were assessed to determine if there was a mathematical relationship common across seedborne bacterial diseases. Bacterial populations were estimated from naturally-infested seeds of cowpea (Vigna unguiculata), peppe...

  5. Protection of probiotic bacteria in synbiotic matrices

    Science.gov (United States)

    Probiotics, like Lactobacillus acidophilus, Lactobacillus reuteri, Bifidobacterium breve, Bifidobacterium longum, when encapsulated with prebiotic fibers such as fructo-oligosaccharides (FOS), inulin (I) and pectic-oligosaccharides (POS), formed a synbiotic matrix system that protected the bacteria ...

  6. Effect of leukocyte hydrolases on bacteria

    International Nuclear Information System (INIS)

    Leukocyte extracts, trypsin, and lysozyme are all capable of releasing the bulk of the LPS from S. typhi, S. typhimurium, and E. coli. Bacteria which have been killed by heat, ultraviolet irradiation, or by a variety of metabolic inhibitors and antibiotics which affect protein, DNA, RNA, and cell wall synthesis no longer yield soluble LPS following treatment with the releasing agents. On the other hand, bacteria which are resistant to certain of the antibiotics yield nearly the full amount of soluble LPS following treatment, suggesting that certain heatabile endogenous metabolic pathways collaborate with the releasing agents in the release of LPS from the bacteria. It is suggested that some of the beneficial effects of antibiotics on infections with gram-negative bacteria may be the prevention of massive release of endotoxin by leukocyte enzymes in inflammatory sites

  7. ¿Desertores o decepcionados? Distintas causas para abandonar los estudios universitarios

    OpenAIRE

    Wietse de Vries; Patricia León Arenas; José Francisco Romero Muñoz; Ignacio Hernández Saldaña

    2011-01-01

    La deserción estudiantil ha sido una preocupación permanente, ya que la mitad de los estudiantes no logra concluir sus estudios. Varias investigaciones sugieren una amplia diversidad de causas posibles, desde factores personales hasta características institucionales. Sin embargo, estos estudios suelen analizar datos de estudiantes, sin entrevistar a los desertores. En este estudio les preguntamos sus motivos para abandonar los estudios y por sus actividades actuales. Aunque hay diversas razon...

  8. Consideraciones para un Mejor Estudio del Suelo y Aclimatación de Cultivos.

    Directory of Open Access Journals (Sweden)

    Bernal. Guillermo

    1940-09-01

    Full Text Available Al hacer el estudio de una zona dada, se hace preciso conocer todos aquellos factores que de una manera u otra, influyen ya directa o indirectamente en la vida vegetal. Sucede muy a menudo entre nosotros, que se tiene el suelo como el único factor que influye favorable o desfavorablemente en el producido de un cultivo, el que éste se mantenga en buenas condiciones. No basta, pues, en considerar el suelo; hay que fijarse en presente el clima, entrando aquí la precipitación, la temperatura, el viento, hay que fijarse en las condiciones que presente el suelo para el desarrollo de bacterias. Todos estos puntos se encuentran influyendo de una manera precisa en los cultivos. Cada uno de ellos hay que considerarlo primero separadamente y luego agruparlos para estudiar el conjunto; solamente así puede obtenerse un conocimiento bastante completo de la zona que se estudia y así se podrá saber con mayores datos si ella sirve.

  9. Electrical Cable Bacteria Save Marine Life

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter

    2016-01-01

    Animals at the bottomof the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron ‘carpet’, trapping toxic hydrogen sulfide.......Animals at the bottomof the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron ‘carpet’, trapping toxic hydrogen sulfide....

  10. Ecology: Electrical Cable Bacteria Save Marine Life

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter

    2016-01-01

    Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide.......Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide....

  11. Microgravity effects on pathogenicity of bacteria

    OpenAIRE

    Wang, Ya-Juan; Liu, Chang-Ting

    2013-01-01

    Microgravity is one of the important environmental conditions during spaceflight. A series of studies have shown that many kinds of bacteria could be detected in space station and space shuttle. Space environment or simulated microgravity may throw a certain influence on those opportunistic pathogens and lead to some changes on their virulence, biofilm formation and drug tolerance. The mechanism of bacteria response to space environment or simulated microgravity has not been defined. However,...

  12. Interactions between ectomycorrhizal associations and bacteria

    OpenAIRE

    Marupakula, Srisailam

    2016-01-01

    Boreal forest podzol soils have vertically stratified horizons with different physico-chemical characteristics and high microbial diversity. Ectomycorrhizal fungi play key roles in accessing nutrients from both organic and mineral substrates. The role of associated bacteria in these processes is still poorly understood. The aim of the studies described in this thesis was to improve understanding of the distribution, diversity and community structure of fungi and bacteria on roots and in soil ...

  13. Magnetization processes in magnetotactic bacteria systems

    Czech Academy of Sciences Publication Activity Database

    Polyakova, T.; Zablotskyy, Vitaliy A.

    2005-01-01

    Roč. 293, - (2005), s. 365-370. ISSN 0304-8853. [International Conference on Scientific and Clinical Aplications of Magnetic Carriers. Lyon, 20.05.04-22.05.04] Grant ostatní: MCF: Nanomag-Lab(XE) N 2004-003177 Institutional research plan: CEZ:AV0Z10100520 Keywords : magnetotactic bacteria * magnetization process * chemotaxis * bacteria * magnetosomes * chain formation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.985, year: 2005

  14. Bacteria in goat meat: Biological danger

    OpenAIRE

    Ivanović S.; Pavlović I.; Žujović M.; Tomić Z.; Memiši N.

    2011-01-01

    In the world, especially in China, India, Pаkistаn and Nigeria goat meat represents an important foodstuff in nutrition of people. Goat meat is being increasingly consumed in Serbia owing to its distinctive taste and desirable chemical composition. As many other types of meat, goat meat can be the source of pathogenic bacteria. Bacteria can find their way into meat of healthy goats or goats with no clinical symptoms premortally (infection) or postmortally (...

  15. Study of Lactobacillus as Probiotic Bacteria

    OpenAIRE

    J. Nowroozi; Mirzaii, M; M. Norouzi

    2004-01-01

    Because of inhibitory effect, selected probiotic lactobacilli may be used as biological preservative, so, the aim of this study was to present some data on lactobacillus as probiotic bacteria. Lactic acid bacteria were isolated from sausage. Each isolate of lactobacillus species was identified by biochemical tests and comparing their sugar fermentation pattern. Antibacterial activities were done by an agar spot, well diffusion and blank disk method. Enzyme sensitivity of supernatant fluid and...

  16. How Bacteria Turn Fiber into Food

    OpenAIRE

    Martens, Eric C.; Lowe, Elisabeth C.; Chiang, Herbert; Nicholas A Pudlo; Wu, Meng; McNulty, Nathan P.; Abbott, D Wade; Henrissat, Bernard; Gilbert, Harry J.; Bolam, David N.; Jeffrey I Gordon

    2011-01-01

    Symbiotic bacteria inhabiting the human gut have evolved under intense pressure to utilize complex carbohydrates, primarily plant cell wall glycans in our diets. These polysaccharides are not digested by human enzymes, but are processed to absorbable short chain fatty acids by gut bacteria. The Bacteroidetes, one of two dominant bacterial phyla in the adult gut, possess broad glycan-degrading abilities. These species use a series of membrane protein complexes, termed Sus-like systems, for cat...

  17. Bacteria under SOS evolve anticancer phenotypes

    OpenAIRE

    Weitao Tao; Dallo Shatha F

    2010-01-01

    Abstract Background The anticancer drugs, such as DNA replication inhibitors, stimulate bacterial adhesion and induce the bacterial SOS response. As a variety of bacterial mutants can be generated during SOS, novel phenotypes are likely to be selected under the drug pressure. Presentation of the hypothesis Bacteria growing with cancer cells in the presence of the replication inhibitors undergo the SOS response and evolve advantageous phenotypes for the bacteria to invade the cancer cells in o...

  18. Characterization of (per)chlorate-reducing bacteria

    OpenAIRE

    Wolterink, A.F.W.M.

    2004-01-01

    Some bacteria can use (per)chlorateas terminal electron acceptor for growth. These bacteria convert perchlorate via chlorate and chlorite into chloride and molecular oxygen. Oxygen formation in microbial respiration is unique. In this study two chlorate-reducing strains belonging to the species Pseudomonas chloritidismutans and a (per)chlorate-reducing strain Dechloromonas hortensis were isolated. The characterization of the chlorate-reducing strain AW-1, which was isolated from a bioreactor ...

  19. Quorum sensing mechanism in lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Hatice Yılmaz - Yıldıran

    2015-04-01

    and detection occurs as a consecution it is hard to understand their QS mechanism. In this review, connection between QS mechanism and some characteristics of lactic acid bacteria are evaluated such as concordance with its host, inhibition of pathogen development and colonization in gastrointestinal system, bacteriocin production, acid and bile resistance, adhesion to epithelium cells. Understanding QS mechanism of lactic acid bacteria will be useful to design metabiotics which is defined as novel probiotics.

  20. Quorum sensing mechanism in lactic acid bacteria

    OpenAIRE

    Hatice Yılmaz - Yıldıran; Aynur Gül Karahan; Gülden Başyiğit - Kılıç

    2015-01-01

    For a long time, microorganisms were considered as just multiplying, finding nutrients and living by themselves organisms. But that belief changed 50 years ago along with the discovery of bacteria communication with each other and environment by microbiologists. The language used in the communication consists of signal molecules and these molecules are generally called 'auto inducer'. Bacteria are capable of measuring density of these molecules and by this way they are able to detect amoun...

  1. Molecular Evolution of Threonine Dehydratase in Bacteria

    OpenAIRE

    Yu, Xuefei; Li, Ye; Wang, Xiaoyuan

    2013-01-01

    Threonine dehydratase converts L-threonine to 2-ketobutyrate. Several threonine dehydratases exist in bacteria, but their origins and evolutionary pathway are unknown. Here we analyzed all the available threonine dehydratases in bacteria and proposed an evolutionary pathway leading to the genes encoding three different threonine dehydratases CTD, BTD1 and BTD2. The ancestral threonine dehydratase might contain only a catalytic domain, but one or two ACT-like subdomains were fused during the e...

  2. Keratinolytic activity of cutaneous and oral bacteria.

    OpenAIRE

    Mikx, F H; De Jong, M H

    1987-01-01

    A test was developed to measure the keratinolytic activity of cutaneous and oral bacteria. Keratin, labeled with fluorescein isothiocyanate, was used in a phosphate buffer (pH 7.2) with 1 mM dithiothreitol. The degradation of keratin was estimated by measuring the fluorescence of the degradation products in the supernatant of the reaction mixtures in a luminescence spectrometer. Several oral and cutaneous bacteria were investigated: Bacteroides gingivalis, Bacteroides intermedius, Treponema d...

  3. Molecular genetic studies on obligate anaerobic bacteria

    International Nuclear Information System (INIS)

    Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

  4. Distribution of coliform bacteria in waste water

    OpenAIRE

    Dau Lal Bohra; Vikas Modasiya; Chandan Kumar Bahura

    2012-01-01

    Biological activity of water can be apparently judged by the colonization of bacteria (microbes). In order to find out the extent of pollution and the relationship between inorganic matters and microbiota, a quantitative and qualitative analysis of bacteria in various types of sewage waters, namely sewage water by the residential colonies (group I), industrial waste water (group II), sewage treatment hub (group III), unorganized collected waste water (group IV) and old residential waste colle...

  5. Horizontal gene transfer between bacteria and animals

    OpenAIRE

    Dunning Hotopp, Julie C.

    2011-01-01

    Horizontal gene transfer is increasingly described between bacteria and animals. Such transfers that are vertically inherited have the potential to influence the evolution of animals. One classic example is the transfer of DNA from mitochondria and chloroplasts to the nucleus after the acquisition of these organelles by eukaryotes. Even today, many of the described instances of bacteria to animal transfer occur as part of intimate relationships like those of endosymbionts and their invertebra...

  6. Study of Lactobacillus as Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    J Nowroozi

    2004-07-01

    Full Text Available Because of inhibitory effect, selected probiotic lactobacilli may be used as biological preservative, so, the aim of this study was to present some data on lactobacillus as probiotic bacteria. Lactic acid bacteria were isolated from sausage. Each isolate of lactobacillus species was identified by biochemical tests and comparing their sugar fermentation pattern. Antibacterial activities were done by an agar spot, well diffusion and blank disk method. Enzyme sensitivity of supernatant fluid and concentrated cell free culture after treatment with α-amylase, lysozyme and trypsin was determined. The isolated bacteria were Lacto. plantarum, Lacto delbruekii, Lacto. acidophilus, Lacto. brevis. The isolated bacteria had strong activity against indicator strains. The antibacterial activity was stable at 100ºC for 10 min and at 56ºC for 30 min, but activity was lost after autoclaving. The maximum production of plantaricin was obtained at 25 - 30ºC at pH 6.5. Because, lactobacilli that used to process sausage fermentation are producing antimicrobial activity with heat stability bacteriocin, so, these bacteria may be considered to be a healthy probiotic diet. Lactobacilli originally isolated from meat products are the best condidates as probiotic bacteria to improve the microbiological safety of these foods.

  7. How methylglyoxal kills bacteria: An ultrastructural study.

    Science.gov (United States)

    Rabie, Erika; Serem, June Cheptoo; Oberholzer, Hester Magdalena; Gaspar, Anabella Regina Marques; Bester, Megan Jean

    2016-01-01

    Antibacterial activity of honey is due to the presence of methylglyoxal (MGO), H2O2, bee defensin as well as polyphenols. High MGO levels in manuka honey are the main source of antibacterial activity. Manuka honey has been reported to reduce the swarming and swimming motility of Pseudomonas aeruginosa due to de-flagellation. Due to the complexity of honey it is unknown if this effect is directly due to MGO. In this ultrastructural investigation the effects of MGO on the morphology of bacteria and specifically the structure of fimbriae and flagella were investigated. MGO effectively inhibited Gram positive (Bacillus subtilis; MIC 0.8 mM and Staphylococcus aureus; MIC 1.2 mM) and Gram negative (P. aeruginosa; MIC 1.0 mM and Escherichia coli; MIC 1.2 mM) bacteria growth. The ultrastructural effects of 0.5, 1.0 and 2 mM MGO on B. substilis and E. coli morphology was then evaluated. At 0.5 mM MGO, bacteria structure was unaltered. For both bacteria at 1 mM MGO fewer fimbriae were present and the flagella were less or absent. Identified structures appeared stunted and fragile. At 2 mM MGO fimbriae and flagella were absent while the bacteria were rounded with shrinkage and loss of membrane integrity. Antibacterial MGO causes alterations in the structure of bacterial fimbriae and flagella which would limit bacteria adherence and motility. PMID:26986806

  8. Peptide conversations in Gram-positive bacteria.

    Science.gov (United States)

    Monnet, Véronique; Juillard, Vincent; Gardan, Rozenn

    2016-05-01

    Within Gram-positive bacteria, the expression of target genes is controlled at the population level via signaling peptides, also known as pheromones. Pheromones control a wide range of functions, including competence, virulence, and others that remain unknown. Until now, their role in bacterial gene regulation has probably been underestimated; indeed, bacteria are able to produce, by ribosomal synthesis or surface protein degradation, an extraordinary variety of peptides which are released outside bacteria and among which, some are pheromones that mediate cell-to-cell communication. The review aims at giving an updated overview of these peptide-dependant communication pathways. More specifically, it follows the whole peptide circuit from the peptide production and secretion in the extracellular medium to its interaction with sensors at bacterial surface or re-import into the bacteria where it plays its regulation role. In recent years, as we have accumulated more knowledge about these systems, it has become apparent that they are more complex than they first appeared. For this reason, more research on peptide-dependant pathways is needed to develop new strategies for controlling functions of interest in Gram-positive bacteria. In particular, such research could lead to alternatives to the use of antibiotics against pathogenic bacteria. In perspective, the review identifies new research questions that emerge in this field and that have to be addressed. PMID:25198780

  9. Molecular probe technology detects bacteria without culture

    Directory of Open Access Journals (Sweden)

    Hyman Richard W

    2012-03-01

    Full Text Available Abstract Background Our ultimate goal is to detect the entire human microbiome, in health and in disease, in a single reaction tube, and employing only commercially available reagents. To that end, we adapted molecular inversion probes to detect bacteria using solely a massively multiplex molecular technology. This molecular probe technology does not require growth of the bacteria in culture. Rather, the molecular probe technology requires only a sequence of forty sequential bases unique to the genome of the bacterium of interest. In this communication, we report the first results of employing our molecular probes to detect bacteria in clinical samples. Results While the assay on Affymetrix GenFlex Tag16K arrays allows the multiplexing of the detection of the bacteria in each clinical sample, one Affymetrix GenFlex Tag16K array must be used for each clinical sample. To multiplex the clinical samples, we introduce a second, independent assay for the molecular probes employing Sequencing by Oligonucleotide Ligation and Detection. By adding one unique oligonucleotide barcode for each clinical sample, we combine the samples after processing, but before sequencing, and sequence them together. Conclusions Overall, we have employed 192 molecular probes representing 40 bacteria to detect the bacteria in twenty-one vaginal swabs as assessed by the Affymetrix GenFlex Tag16K assay and fourteen of those by the Sequencing by Oligonucleotide Ligation and Detection assay. The correlations among the assays were excellent.

  10. Competition for hydrogen by human faecal bacteria: evidence for the predominance of methane producing bacteria.

    OpenAIRE

    Strocchi, A; Furne, J K; Ellis, C J; Levitt, M D

    1991-01-01

    Studies of sludge have shown that some species of sulphate reducing bacteria outcompete methane producing bacteria for the common substrate H2. A similar competition may exist in human faeces where the methane (CH4) producing status of an individual depends on the faecal concentration of sulphate reducing bacteria. To determine if non-methanogenic faeces outcompete CH4 producing faeces for H2, aliquots of each type of faeces were incubated alone or mixed together, with or without addition of ...

  11. Antioxidant activity of Sphaerococcus coronopifolius associated bacteria

    Directory of Open Access Journals (Sweden)

    Nádia Fino

    2014-06-01

    Full Text Available Associated bacteria living on macroalgae surfaces are an interesting source of new secondary metabolites with biological activities. The aim of this study was the isolation and identification of epiphytic bacteria from the marine algae Sphaerococcus coronopifolius and the evaluation of the antioxidant activity of the bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1 extraction. Antioxidant activity was evaluated by quantification of total phenolic content (TPC, 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging activity and oxygen radical absorbent capacity (ORAC. The extracts with higher antioxidant activity were tested on MCF-7 and HepG-2 cell lines in oxidative stress conditions induced by H2O2 at 0.2 mM and 0.5 mM, respectively. In total were isolated 21 Sphaerococcus coronopifolius associated bacteria and identified as Vibrio sp. (28.57%, Shewanella sp. (23.81%, Pseudoalteromonas sp. (19.05%, Bacillus sp. (9.52% and Halomonas sp. (9.52%. Two (9.52% of them presented less than 90% Basic Local Alignment Search Tool (BLAST match. The epiphytic bacteria with the most antioxidant potential evaluated by ORAC and DPPH methods were Sp2, Sp12, Sp23, Sp25 and Sp27. The strain Sp4 show high antioxidant activity in all antioxidant methods (ORAC, DPPH and TPC. In oxidative stress conditions on MCF-7 cell line, the extracts of bacteria (1mg.ml-1: 24hours Sp4 (16.15%, Sp25 (17.95% and Sp27 (10.65% prevented the cell death induced by H2O2. In the HepG-2 cell line was the extracts of Sp2 (9.01%, Sp4 (11.21%, Sp12 (7.20% and Sp23 (8.81% bacteria that high prevented the oxidative stress condition induced by H2O2. In conclusion, the Sphaerococcus coronopifolius associated bacteria can be an interesting and excellent source of marine natural compounds with antioxidant activity.

  12. Magnetosome chain superstructure in uncultured magnetotactic bacteria

    International Nuclear Information System (INIS)

    Magnetotactic bacteria produce magnetosomes, which are magnetic particles enveloped by biological membranes, in a highly controlled mineralization process. Magnetosomes are used to navigate in magnetic fields by a phenomenon called magnetotaxis. Two levels of organization and control are recognized in magnetosomes. First, magnetotactic bacteria create a spatially distinct environment within vesicles defined by their membranes. In the vesicles, the bacteria control the size, composition and purity of the mineral content of the magnetic particles. Unique crystal morphologies are produced in magnetosomes as a consequence of this bacterial control. Second, magnetotactic bacteria organize the magnetosomes in chains within the cell body. It has been shown in a particular case that the chains are positioned within the cell body in specific locations defined by filamentous cytoskeleton elements. Here, we describe an additional level of organization of the magnetosome chains in uncultured magnetotactic cocci found in marine and freshwater sediments. Electron microscopy analysis of the magnetosome chains using a goniometer showed that the magnetic crystals in both types of bacteria are not oriented at random along the crystal chain. Instead, the magnetosomes have specific orientations relative to the other magnetosomes in the chain. Each crystal is rotated either 60°, 180° or 300° relative to their neighbors along the chain axis, causing the overlapping of the (1 1 1) and (1-bar 1-bar 1-bar) capping faces of neighboring crystals. We suggest that genetic determinants that are not present or active in bacteria with magnetosomes randomly rotated within a chain must be present in bacteria that organize magnetosomes so precisely. This particular organization may also be used as an indicative biosignature of magnetosomes in the study of magnetofossils in the cases where this symmetry is observed

  13. doméstico. Discusiones y estudios recientes

    Directory of Open Access Journals (Sweden)

    Patricia Arias

    2013-01-01

    Full Text Available Con base en la revisión de algunos estudios recientes que se han llevado a cabo en diver- sas comunidades rurales de las nuevas regiones migratorias, en este artículo se revisan, de manera crítica, dos interpretaciones de los estudios sobre la familia rural: la economía campesina como unidad de producción-consumo y el ciclo de desarrollo de la unidad doméstica. En las condiciones actuales la migración, interna e internacional, desem- peña un papel decisivo en las comunidades rurales. Muchos estudios han constatado la voluntad de las mujeres de salir de los grupos domésticos y sumarse a los flujos migra- torios por motivos particulares, por situaciones y demandas específicas de ellas; su salida ha contribuido al resquebrajamiento de los sistemas tradicionales de organización y re- producción de la familia campesina. Las feministas, y más tarde los estudios con la perspectiva de género, criticaron la visión de que las familias rurales constituían unidades de producción-consumo donde las decisiones correspondían a un modelo de estrategias familiares de sobrevivencia y reproducción (Hondagneu-Sotelo, 2007; Wolf, 1990. Ese modelo privilegiaba la homo- geneidad, la colectividad, la solidaridad y el consenso, es decir, suponía que en los hogares no había conflictos ni tensiones a la hora de tomar decisiones que a todos com- prometían (Ariza, 2007. La familia era una “unidad económica moral” que se susten- taba en los principios de “reciprocidad, consenso y altruismo” (Grasmuck y Pessar, 1991. Los estudios desde el enfoque de género señalaron que en las familias había relacio- nes de poder basadas en una distribución jerárquica y desigual de los derechos, recursos y autoridad que afectaban especialmente a las mujeres (Ariza, 2007; González Montes, 2002; Hondagneu-Sotelo, 2007; Wolf, 1990. Las críticas alcanzaron a los estudios migratorios: la migración no era un fenómeno exclusivamente de los hombres, las mi

  14. Apoyo a Estudios Geodinamicos con GPS en Guatemala

    Science.gov (United States)

    Robles, V. R.

    2013-05-01

    El Instituto Geografico Nacional de Guatemala implemento 17 estaciones GNSS en el año 2009, como un proyecto de credito mixto de donacion de equipamiento del Gobierno de Suiza, el cual, este equipamiento de estaciones CORS GNSS es un sistema de recepción y transmisión de datos crudos GPS RInex que utiliza la tecnologia Spider Web de Leica, asi mismo este sistema esta sirviendo para el espablecimiento de un marco geodesico nacional de coordenadas geodesicas oficiales, el cual se calculan u obtienen las velocidades en tiempos temporales programados de las 17 Estaciones CORS. La infraestructura del marco geodesico de Guatemala esta sirviendo de base para las aplicaciones de estudios geodinamicos como el monitoreo de del desplazamiento de las placas tectonicas por medio de un estudio que se inicio en el año de 1999, llamado medicion con GPS el sistema de Fallas de los rios Polochic Motagua de Guatemala, tambien para un estudio que se implemento para deformación de corteza terrestre local en un Volcan Activo de Guatemala llamado Pacaya. Para el estudio de medicion con GPS en el sistema de falla de los Rios del polochic Motagua se implementaron 16 puntos para medir con GPS de dos frecuencias en el año de 1999, el cual, tres puntos son estaciones geodesicas CORS IGS llamados GUAT, ELEN y HUEH, despues en el año de 2003 se hizo otra medicion en un total de 20 puntos, que permitió calcular las velocidades de desplazamieinto de los puntos en mención, usando como referencia el modelo NUVEL 1A de DeMets de la placa de Norteamerica. Este estudio fue en cooperación internacional por la universidad de Nice de Francia y el IGNde Francia. Para el estudio del monitoreo con GPS del volcan activo de Guatemala, se implementaron cuatro puntos al rededor del volcan, el cual, se realizan cuatro mediciones al año, que permiten determinar axialmente la distancias entre los puntos, y rebisar estadisticamente cual es el comportamiento de las distancias en funcion del tiempo, si

  15. Estudio histórico y constructivo del Palacio de los Valeriola

    OpenAIRE

    GARCÍA LLISO, ALEJANDRO; MUÑOZ DOMINGO, VERÓNICA

    2013-01-01

    El presente proyecto tiene por objeto realizar el estudio y levantamiento gráfico actual del Palacio de los Valerio la de la Calle del Mar un edificio emblemático tanto desde el punto de vista histórico, ya que su construcción data del siglo XVII, como arquitectónico. El proyecto incluye el estudio de las diversas modificaciones, el estudio constructivo y de los materiales empleados en el edificio y un estudio de las patologías observadas en todo su conjunto, además de un exhaustivo estudio d...

  16. Nutritional Interdependence Among Rumen Bacteria During Cellulose Digestion In Vitro

    OpenAIRE

    Miura, Hideki; HORIGUCHI, Masaaki; Ogimoto, Keiji; MATSUMOTO, Tatsuro

    1983-01-01

    A study has been made of the promoting effect of starch on cellulose digestion by mixed rumen bacteria in a cellulose-urea medium. Starch supplementation of the medium promoted the growth of bacteria that required neither amino acids (AA) nor branched-chain fatty acids (BrFA). The growth of these bacteria was followed by the growth of AA-dependent bacteria, AA- or BrFA-dependent bacteria, BrFA-producing bacteria, and finally, BrFA-dependent cellulolytic bacteria. Population changes of these b...

  17. Method of Detecting Coliform Bacteria and Escherichia Coli Bacteria from Reflected Light

    Science.gov (United States)

    Vincent, Robert (Inventor)

    2013-01-01

    The present invention relates to a method of detecting coliform bacteria in water from reflected light and a method of detecting Eschericha Coli bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  18. Bacteria and plutonium in marine environments

    International Nuclear Information System (INIS)

    Microbes are important in geochemical cycling of many elements. Recent reports emphasize biogenous particulates and bacterial exometabolites as controlling oceanic distribution of plutonium. Bacteria perform oxidation/reduction reactions on metals such as mercury, nickel, lead, copper, and cadmium. Redox transformations or uptake of Pu by marine bacteria may well proceed by similar mechanisms. Profiles of water samples and sediment cores were obtained along the continental shelf off Nova Scotia and in the Gulf of St. Lawrence. Profiles of water samples, and sediment cores were obtained. Epifluorescent microscopy was used to view bacteria (from water or sediment) after concentration on membrane filters and staining with acridine orange. Radiochemical analyses measured Pu in sediments and water samples. Studies of 237Pu uptake used a strain of Leucothrix mucor isolated from a macroalga. Enumeration shows bacteria to range 104 to 105 cells/ml in seawater or 107 to 108 cells/gram of sediment. These numbers are related to the levels and distrbution of Pu in the samples. In cultures of L. mucor amended with Pu atom concentrations approximating those present in open ocean environments, bacterial cells concentrated 237Pu slower and to lower levels than did clay minerals, glass beads, or phytoplankton. These data further clarify the role of marine bacteria in Pu biogeochemistry

  19. Molecular analysis of deep subsurface bacteria

    International Nuclear Information System (INIS)

    Deep sediments samples from site C10a, in Appleton, and sites, P24, P28, and P29, at the Savannah River Site (SRS), near Aiken, South Carolina were studied to determine their microbial community composition, DNA homology and mol %G+C. Different geological formations with great variability in hydrogeological parameters were found across the depth profile. Phenotypic identification of deep subsurface bacteria underestimated the bacterial diversity at the three SRS sites, since bacteria with the same phenotype have different DNA composition and less than 70% DNA homology. Total DNA hybridization and mol %G+C analysis of deep sediment bacterial isolates suggested that each formation is comprised of different microbial communities. Depositional environment was more important than site and geological formation on the DNA relatedness between deep subsurface bacteria, since more 70% of bacteria with 20% or more of DNA homology came from the same depositional environments. Based on phenotypic and genotypic tests Pseudomonas spp. and Acinetobacter spp.-like bacteria were identified in 85 million years old sediments. This suggests that these microbial communities might have been adapted during a long period of time to the environmental conditions of the deep subsurface

  20. Fossil bacteria in Xuanlong iron ore deposits of Hebei Province

    Institute of Scientific and Technical Information of China (English)

    DAI Yongding; SONG Haiming; SHEN Jiying

    2004-01-01

    Discovered in Early Proterozoic Xuanlong iron ore deposits are six genera of fossil iron bacteria, i. e. sphere (coenobium of) rod-shaped (monomer) Naumanniella, ellipsoid elliptical Ochrobium, sphere spherical Siderocapsa and chain spherical Siderococcus, chain rod-shaped Leptothrix and Lieskeella, and six genera of fossil blue bacteria, namely sphere spherical Gloeocapsa, Synechocystis and Globobacter, chain spherical Anabaena and Nostoc, and constrictive septate tubular Nodularia. The biomineralized monomers and coenobia of the two categories of bacteria, together with hematite plates made up the bacteria pelletal, bacteria silky,bacteria fibrous and clasty bacteria pelletal textural lamina. The bacteria pelletal laminae combined with other bacteria laminae to make up oncolite, stromatolite and laminate. The precipitation of iron oxide was accelerated due to iron and blue bacteria cohabiting on microbial film or mat. The Xuanlong iron ore deposits are microbial binding ore deposits of ocean source.

  1. PROFESORES PRINCIPIANTES E INICIACIÓN PROFESIONAL. ESTUDIO EXPLORATORIO

    Directory of Open Access Journals (Sweden)

    Raúl Eirín Nemiña

    2009-01-01

    Full Text Available En este trabajo presentamos los avances de un estudio llevado a cabo con profesores que acceden a la condición de funcionarios docentes. Comenzamos estudiando las aportaciones teóricas que sustentan el interés por el estudio del período de iniciación profesional. En el apartado empírico, mediante la aplicación de un cuestionario, hemos explorado cuestiones como la edad, sexo, experiencia docente previa, contexto del centro de trabajo y motivaciones iniciales de entrada a al profesión docente. También valoramos, apoyándonos en los hallazgos recogidos en la literatura sobre el tema, los problemas y preocupaciones que encaran los profesores de nuestra muestra.

  2. Gran Hermano : Estudio de recepción

    OpenAIRE

    Rigo, Marisa Natalia

    2008-01-01

    La presente investigación científica trata sobre el reality show Gran Hermano, basándose en un estudio de recepción sobre el significado que tiene el programa para jóvenes entre 20 y 28 años de la ciudad de La Plata. El estudio de recepción fue elegido por considerar que es el más pertinente para tener un conocimiento profundo a la hora de identificar qué sentido tiene en los jóvenes Gran Hermano y así poder establecer el significado que le otorgan. De qué modo se apropian de este formato tel...

  3. Estudio del transporte vertical de un edificio de oficinas

    OpenAIRE

    Sánchez Gámez, Isabel

    2013-01-01

    El presente documento estudia un proyecto completo de ingeniería del transporte vertical de un edificio de oficinas. El transporte vertical de un edificio es una de las instalaciones fundamentales a la hora de diseñar el edificio. Un diseño incorrecto del núcleo de ascensores puede originar graves problemas a los usuarios y un sobredimensionamiento puede elevar los costes de mantenimiento innecesariamente. El estudio del transporte vertical de un edificio consta de dos parte...

  4. El Grupo de Estudios Peirceanos de la Universidad de Navarra

    OpenAIRE

    Barrena, S.; Nubiola, J. (Jaime)

    2006-01-01

    In this report the history and main activities of the Grupo de Estudios Peirceanos at the University of Navarra is presented. It was created in 1994 to promote the study of the work of Charles S. Peirce (1839-1914), especially in Spain and in the Spanish-speaking countries. An outstanding result of the work of this group is the massive installment in the web of Peirce’s texts translated into Spanish.

  5. Lenguaje y sociedad: estudio de un caso de laboratorio

    OpenAIRE

    Allones Pérez, Carlos

    1999-01-01

    El estudio de un caso de laboratorio nos permite en este artículo establecer la distinción entre forma y contenido en el análisis de las relaciones humanas, distinción que nos lleva a comprender lo que tienen en común todas ellas, más allá de su fascinante diversidad, y hace posible el conocimiento científico de las mismas, en cualquier lugar y tiempo.

  6. Aspectos claves para elaborar un estudio de clima laboral

    OpenAIRE

    Mena Gómez, Luis Alberto

    2014-01-01

    El siguiente trabajo contiene los resultados de un estudio de medición de clima laboral, aplicando cinco dimensiones: Formación, Comunicación Interna, Situación Profesional y Perspectivas de Desarrollo e Imagen corporativa, realizado en una empresa de distribución alimentaria. Los distintos aspectos valorados en la elaboración de una encuesta se han aplicado en la investigación realizada.

  7. La actuación y los Estudios Literarios

    Directory of Open Access Journals (Sweden)

    Karina Mauro

    2011-05-01

    de los estudios literarios en la investigación sobre la Actuación a partir del análisis de los conceptos de representación y mimesis aristotélica y de los problemas que acarrea la aplicación de estos conceptos en el análisis de la acción del actor en escena.

  8. Estudio de las funciones ejecutivas en el envejecimiento

    OpenAIRE

    Rosa, Beatriz Alice Leal da Silva Alves

    2013-01-01

    [ES] Este estudio tuvo como objetivos generales, analizar los rendimientos ejecutivos de adultos normales portugueses, de ambos sexos, teniendo en cuenta los diferentes componentes que integran las funciones ejecutivas y examinar si, en la tercera edad, los rendimientos ejecutivos se relacionan con las actividades sociales y con las actividades básicas e instrumentales de la vida diaria. Específicamente, se ha pretendido conocer si existen variaciones en la ejecución de tareas ejecutivas ...

  9. Inhibition of seafood-borne bacteria in cooked mackerel (Rastrelliger kanagurta) fish meat by lactic acid bacteria

    OpenAIRE

    Kanappan, S.; G. Gopikrishna

    2008-01-01

    Antagonistic activity of lactic acid bacteria (LAB) namely Streptococcus faecalis, Pediococcus cerevisiae and Lactobacillus casei was tested against seafood-borne bacteria such as Staphylococcus aureus, Bacillus cereus, Escherichia coli, Clostridium perfringens and Listeria monocytogenes. Three lactic acid bacteria such as Streptococcus faecalis, Lactobacillus casei and Pediococcus cerevisiae were coated on cooked mackerel meat, individually and in combination against fish-borne bacteria. S. ...

  10. Using Fluorescent Viruses for Detecting Bacteria in Water

    Science.gov (United States)

    Tabacco, Mary Beth; Qian, Xiaohua; Russo, Jaimie A.

    2009-01-01

    A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest.

  11. Applications of Magnetosomes Synthesized by Magnetotactic Bacteria in Medicine

    OpenAIRE

    EdouardAlphandéry

    2014-01-01

    Magnetotactic bacteria belong to a group of bacteria that synthesize iron oxide nanoparticles covered by biological material that are called magnetosomes. These bacteria use the magnetosomes as a compass to navigate in the direction of the earth’s magnetic field. This compass helps the bacteria to find the optimum conditions for their growth and survival. Here, we review several medical applications of magnetotactic bacteria and magnetosomes, such as those in magnetic resonance imaging (MRI),...

  12. Bacteriocins From Lactic Acid Bacteria: Interest For Food Products Biopreservation

    OpenAIRE

    Dortu, C.; Thonart, Philippe

    2009-01-01

    Bacteriocins from lactic acid bacteria: interest for food products biopreservation. Bacteriocins from lactic acid bacteria are low molecular weight antimicrobial peptides. They have inhibitory activity against the bacteria that are closed related to the producer strains and a narrow inhibitory spectrum. Nevertheless, most of them have activity against some food-born pathogenic bacteria as Listeria monocytogenes. The application of bacteriocins or bacteriocin producing lactic acid bacteria in ...

  13. Quantification and Qualification of Bacteria Trapped in Chewed Gum

    OpenAIRE

    Wessel, Stefan W.; van der Mei, Henny C.; Morando, David; Slomp, Anje M.; van de Belt-Gritter, Betsy; Maitra, Amarnath; Busscher, Henk J.

    2015-01-01

    Chewing of gum contributes to the maintenance of oral health. Many oral diseases, including caries and periodontal disease, are caused by bacteria. However, it is unknown whether chewing of gum can remove bacteria from the oral cavity. Here, we hypothesize that chewing of gum can trap bacteria and remove them from the oral cavity. To test this hypothesis, we developed two methods to quantify numbers of bacteria trapped in chewed gum. In the first method, known numbers of bacteria were finger-...

  14. Estudios marxistas de la cultura y los medios

    Directory of Open Access Journals (Sweden)

    Roy Alfaro Vargas

    2016-05-01

    Full Text Available Este artículo introduce los Estudios Marxistas de la Cultura y los Medios (EMCM a Latinoamérica y expone los principales fundamentos teóricos y epistemológicos de los estudios marxistas de la cultura y los medios. Se analiza la relación entre la teoría de la auto-organización, la dialéctica y la teoría crítica, alrededor del estudio de la Web 2.0 y de los sitios de redes sociales. Además, se explica el rol de la teoría marxiana del valor dentro de los EMCM, como medio para establecer la crítica del trabajo digital alienado realizado por el usuario de los sitios de redes sociales. En este sentido, se expone el concepto de Web 3.0 como medio para la superación dialéctica de la Web 2.0, en cuanto proceso de participación democrática, basada en la construcción de medios alternativos.

  15. All ecosystems potentially host electrogenic bacteria.

    Science.gov (United States)

    Chabert, Nicolas; Amin Ali, Oulfat; Achouak, Wafa

    2015-12-01

    Instead of requiring metal catalysts, MFCs utilize bacteria that oxidize organic matter and either transfer electrons to the anode or take electrons from the cathode. These devices are thus based on a wide microbial diversity that can convert a large array of organic matter components into sustainable and renewable energy. A wide variety of explored environments were found to host electrogenic bacteria, including extreme environments. In the present review, we describe how different ecosystems host electrogenic bacteria, as well as the physicochemical, electrochemical and biological parameters that control the currents from MFCs. We also report how using new molecular techniques allowed characterization of electrochemical biofilms and identification of potentially new electrogenic species. Finally we discuss these findings in the context of future research directions. PMID:26298511

  16. Urban ants and transportation of nosocomial bacteria.

    Science.gov (United States)

    Rodovalho, Cynara M; Santos, Ana L; Marcolino, Marcus T; Bonetti, Ana M; Brandeburgo, Malcon A M

    2007-01-01

    Many ant species displaying synanthropic behavior that have successfully dispersed in urban areas can cause problems in hospitals by acting as bacterial vectors. In this study, we encountered bacteria on ants collected at the Universidade Federal de Uberlândia hospital, in the campus and at households nearby. The ants were identified as Tapinoma melanocephalum (Fabricius) and Camponotus vittatus (Forel) (Hymenoptera: Formicidae) and the bacterial strains found here belong to the group of the coagulase-positive staphylococcus, coagulase-negative staphylococcus and gram negative bacilli, including antimicrobial drug-resistant strains. An investigation of the bacteria found in the ants and in the environment revealed that some ants carried non-isolated bacteria from the same environment and with high levels of resistance, evidencing the transmission potential of these insects. PMID:17710329

  17. Biodegradation of Complex Bacteria on Phenolic Derivatives in River Water

    Institute of Scientific and Technical Information of China (English)

    GUANG-HUA LU; CHAO WANG; ZHE SUN

    2009-01-01

    Objective To isolate, incubate, and identify 4-chlorophenol-degrading complex bacteria, determine the tolerance of these bacteria to phenolic derivatives and study their synergetic metabolism as well as the aboriginal microbes and co-metabolic degradation of mixed chlorophenols in river water. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicants. Biodegradability of phenolic derivatives was determined by adding 4-chlorophenol-degrading bacteria in river water. Results The complex bacteria were identified as Mycopiana, Alcaligenes, Pseudvmonas, and Flavobacterium. The domesticated complex bacteria were more tolerant to phenolic derivatives than the aboriginal bacteria from Qinhuai River. The biodegradability of chlorophenols, dihydroxybenzenes and nitrophenols under various aquatic conditions was determined and compared. The complex bacteria exhibited a higher metabolic efficiency on chemicals than the aboriginal microbes, and the final removal rate of phenolic derivatives was increased at least by 55% when the complex bacteria were added into river water. The metabolic relationship between dominant mixed bacteria and river bacteria was studied. Conclusion The complex bacteria domesticated by 4-chlorophenol can grow and be metabolized to take other chlorophenols, dihydroxybenzenes and nitrophenols as the sole carbon and energy source. There is a synergetic metabolism of most compounds between the aboriginal microbes in river water and the domesticated complex bacteria. 4-chlorophenol-degrading bacteria can co-metabolize various chlorophenols in river water.

  18. Modulating immune responses with probiotic bacteria.

    Science.gov (United States)

    Matsuzaki, T; Chin, J

    2000-02-01

    For many years, probiotic bacteria have been known to confer health benefits to the consumer. One possible mechanism for this may be the ability of probiotic bacteria to modulate immune responses. Oral administration of Lactobacillus casei strain Shirota (LcS) has been found to enhance innate immunity by stimulating the activity of splenic NK cells. Oral feeding with killed LcS was able to stimulate the production of Th1 cytokines, resulting in repressed production of IgE antibodies against Ovalbumin in experimental mice. The ability to switch mucosal immune responses towards Th1 with probiotic bacteria provides a strategy for treatment of allergic disorders. Growth of Meth A tumour cells in the lungs was also inhibited by intrapleural injection of LcS. Oral administration of other probiotic bacteria, such as Streptococcus thermophilus (St), Lactobacillus fermentum (Lf) and yeast (Y), elicited different immune responses. Mice that were prefed yeast or Lf followed by feeding with ovalbumin (OVA) responded better to vaccination with OVA than mice not given either probiotic or OVA or mice that had been prefed only OVA. However, antibody responses were significantly suppressed in response to vaccination with OVA in mice that had been prefed yeast followed by yeast and OVA as well as mice prefed Lf followed by Lf and OVA. Prefeeding St followed by OVA feeding enhanced cellular immune responses against ovalbumin. In contrast, mice prefed St followed by St + OVA were hyporesponsive against OVA. While antigen feeding alone appears to prime for an immune response, cofeeding antigen with probiotic bacteria can suppress both antibody and cellular immune responses and may provide an efficacious protocol to attenuate autoimmune diseases, such as experimental allergic encephalomyelitis, by jointly dosing with myelin basic protein and probiotic bacteria. PMID:10651931

  19. Bacteria Provide Cleanup of Oil Spills, Wastewater

    Science.gov (United States)

    2010-01-01

    Through Small Business Innovation Research (SBIR) contracts with Marshall Space Flight Center, Micro-Bac International Inc., of Round Rock, Texas, developed a phototrophic cell for water purification in space. Inside the cell: millions of photosynthetic bacteria. Micro-Bac proceeded to commercialize the bacterial formulation it developed for the SBIR project. The formulation is now used for the remediation of wastewater systems and waste from livestock farms and food manufacturers. Strains of the SBIR-derived bacteria also feature in microbial solutions that treat environmentally damaging oil spills, such as that resulting from the catastrophic 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico.

  20. Bacteria-Triggered Release of Antimicrobial Agents

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V.; Chiang, Wen-Chi; Tolker-Nielsen, Tim;

    2014-01-01

    Medical devices employed in healthcare practice are often susceptible to microbial contamination. Pathogenic bacteria may attach themselves to device surfaces of catheters or implants by formation of chemically complex biofilms, which may be the direct cause of device failure. Extracellular...... material is demonstrated by the bacteria‐triggered release of antibiotics to control bacterial populations and signaling molecules to modulate quorum sensing. The self‐regulating system provides the basis for the development of device‐relevant polymeric materials, which only release antibiotics in...... dependency of the titer of bacteria surrounding the medical device....

  1. Degradation of monomethylhydrazine by two soil bacteria

    International Nuclear Information System (INIS)

    It has been reported that three heterotrophic soil bacteria had the capacity to degrade hydrazine. One of these organisms, Achromobacter sp., degraded hydrazine to N2 gas. Furthermore, it was reported that monomethylhydrazine (MMH) in Arredondo fine sand was mineralized to CO2, and that such degradation is microbial. However, microorganisms that degrade MMH have not been reported. MMH and hydrazine are chemically similar to one another. Therefore, this study was initiated to test the capacity of the two hydrazine-degrading bacteria, Achromobacter sp. and Pseudomonas sp., to degrade MMH

  2. Bacterial biofilms. Bacteria Quorum sensing in biofilms

    Directory of Open Access Journals (Sweden)

    E. S. Vorobey

    2012-03-01

    Full Text Available Data on biofilms, their structure and properties, peculiarities of formation and interaction between microorganisms in the film are presented. Information on discovery and study of biofilms, importance of biofilms in the medical and clinical microbiology are offered. The data allow to interpret biofilm as a form of existence of human normal microflora. For the exchange of information within the biofilm between the individual cells of the same or different species bacteria use the signal molecules of the Quorum sensing system. Coordination of bacterial cells activity in the biofilms gives them significant advantages: in the biofilms bacteria are protected from the influence of the host protective factors and the antibacterial drugs.

  3. Functional Encyclopedia of Bacteria and Archaea

    Energy Technology Data Exchange (ETDEWEB)

    Blow, M. J.; Deutschbauer, A. M.; Hoover, C. A.; Lamson, J.; Lamson, J.; Price, M. N.; Waters, J.; Wetmore, K. M.; Bristow, J.; Arkin, A. P.

    2013-03-20

    Bacteria and Archaea exhibit a huge diversity of metabolic capabilities with fundamental importance in the environment, and potential applications in biotechnology. However, the genetic bases of these capabilities remain unclear due largely to an absence of technologies that link DNA sequence to molecular function. To address this challenge, we are developing a pipeline for high throughput annotation of gene function using mutagenesis, growth assays and DNA sequencing. By applying this pipeline to annotate gene function in 50 diverse microbes we hope to discover thousands of new gene functions and produce a proof of principle `Functional Encyclopedia of Bacteria and Archaea?.

  4. Presencia de bacterias asociadas a nieve marina en arrecifes influenciados por escorrentía continental del Caribe colombiano: primer acercamiento

    Directory of Open Access Journals (Sweden)

    Hernán Alejandro Henao-Castro

    2015-06-01

    Full Text Available Parte del deterioro de los arrecifes de coral se atribuye al efecto del aporte de agua dulce cargada de nutrientes y sedimentos finos. Estas condiciones favorecen la formación de nieve marina lodosa que transporta gran carga de bacterias que pueden ser patógenos de corales. Por lo anterior, se estudió la presencia de bacterias asociadas a nieve marina lodosa en una zona arrecifal del Caribe colombiano en un gradiente de distancia a la desembocadura del canal del Dique (Cartagena. Por medio de técnicas moleculares PCR-DGGE, se registró baja riqueza, con bandas representativas de siete bacterias diferentes. El número de especies varió según el sitio, pero no hubo relación con la cercanía a la fuente de escorrentía. Como estudio pionero, sirve como punto de partida para estudios en arrecifes del Caribe colombiano impactados por escorrentía.

  5. Musca domestica como vector mecánico de bacterias enteropatógenas en mercados y basurales de Lima y Callao

    Directory of Open Access Journals (Sweden)

    Vilma Béjar C

    2006-01-01

    Full Text Available Objetivos: Demostrar que la mosca doméstica (Musca domestica es un vector mecánico de bacterias enteropatógenas en distritos de Lima y Callao. Materiales y Métodos: Estudio de tipo descriptivo transversal. Unidad de estudio: Musca domestica. Entre mayo de 2004 y julio de 2005 se realizó un muestreo en diferentes distritos de las provincias de Lima y el Callao teniendo en cuenta el índice de infestación de cada zona elegida. Se recolectaron moscas de mercados, periferia y basurales aledaños. En el laboratorio fueron procesadas en medios de cultivo para aislamiento de enterobacterias y su identificación. Resultados: De un total de 780 moscas domésticas se aisló Escherichia coli enteropatógena, Salmonella typhi, Shigella flexneri y Yersinia enterocolitica. Se estableció una relación directa entre el hallazgo de bacterias enteropatógenas y las zonas de mayor grado de infestación (20 moscas/hora de observación. Conclusión: El aislamiento de bacterias enteropatógenas en Musca domestica permitió demostrar su papel vector.

  6. Bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.

    Science.gov (United States)

    Gong, Xiao-Cui; Liu, Ze-Shen; Guo, Peng; Chi, Chang-Qiao; Chen, Jian; Wang, Xing-Biao; Tang, Yue-Qin; Wu, Xiao-Lei; Liu, Chun-Zhong

    2012-01-01

    Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR). However, it is not entirely clear if "endogenous" bacteria (e.g., spores) in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain). The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP) analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil. PMID:23028421

  7. Bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.

    Directory of Open Access Journals (Sweden)

    Xiao-Cui Gong

    Full Text Available Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR. However, it is not entirely clear if "endogenous" bacteria (e.g., spores in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain. The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil.

  8. Heterotrophic bacteria in drinking water distribution system: a review.

    Science.gov (United States)

    Chowdhury, Shakhawat

    2012-10-01

    The microbiological quality of drinking water in municipal water distribution systems (WDS) depends on several factors. Free residual chlorine and/or chloramines are typically used to minimize bacterial recontamination and/or regrowth in WDS. Despite such preventive measures, regrowth of heterotrophic (HPC) and opportunistic bacteria in bulk water and biofilms has yet to be controlled completely. No approach has shown complete success in eliminating biofilms or HPC bacteria from bulk water and pipe surfaces. Biofilms can provide shelter for pathogenic bacteria and protect these bacteria from disinfectants. Some HPC bacteria may be associated with aesthetic and non-life threatening diseases. Research to date has achieved important success in understanding occurrence and regrowth of bacteria in bulk water and biofilms in WDS. To achieve comprehensive understanding and to provide efficient control against bacteria regrowth, future research on bacteria regrowth dynamics and their implications is warranted. In this study, a review was performed on the literature published in this area. The findings and limitations of these papers are summarized. Occurrences of bacteria in WDS, factors affecting bacteria regrowth in bulk water and biofilms, bacteria control strategies, sources of nutrients, human health risks from bacterial exposure, modelling of bacteria regrowth and methods of bacteria sampling and detection and quantification are investigated. Advances to date are noted, and future research needs are identified. Finally, research directions are proposed to effectively control HPC and opportunistic bacteria in bulk water and biofilms in WDS. PMID:22076103

  9. Antimicrobial resistant bacteria in the food chain

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar

    Antimicrobials are used for treatment and prevention of disease in food animals and as feed additives for growth promotion. All uses lead to the development of resistant bacteria, some of which are pathogenic to humans. Current main concerns are with resistance in Salmonella and Campylobacter to...

  10. Radiographic markers - A reservoir for bacteria?

    Energy Technology Data Exchange (ETDEWEB)

    Tugwell, Jenna, E-mail: jenna.tugwell@googlemail.co [Department of Radiology, Ysbyty Gwynedd Hospital, Bangor, North Wales (United Kingdom); Maddison, Adele [Nuffield Health, Shrewsbury Hospital (United Kingdom)

    2011-05-15

    Introduction: Amongst the most frequently handled objects in the radiology department are radiographic markers. They are personal accessories used with every patient, and are kept in the radiographers pockets when not utilised. Upon enquiry it was discovered that many radiographers disregarded the potential of these accessories to become a vector for cross-contamination thus never or rarely clean them. The aims of this study were therefore to identify if radiographic markers are a reservoir for bacteria and to establish an effective cleaning method for decontaminating them. Methodology: 25 radiographers/student radiographers were selected for this study. Swabbing of their markers prior and post cleaning took place. The microbiology laboratory subsequently analyzed the results by quantifying and identifying the bacteria present. The participants also completed a closed questionnaire regarding their markers (e.g. frequency of cleaning and type of marker) to help specify the results gained from the swabbing procedure. Results: From the sample swabbed, 92% were contaminated with various organisms including Staphylococcus and Bacillus species, the amount of bacteria present ranged from 0 to >50 CFU. There were no significant differences between disinfectant wipes and alcohol gel in decontaminating the markers. Both successfully reduced their bacterial load, with 80% of the markers post cleaning having 0 CFU. Conclusion: The results indicated that radiographic markers can become highly contaminated with various organisms thus serve as a reservoir for bacteria. In addition, the markers need to be cleaned on a regular basis, with either disinfectant wipes or alcohol gel to reduce their bacterial load.

  11. Genetics of proteinases of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan; Venema, Gerhardus

    1988-01-01

    Because it is essential for good growth with concomitant rapid acid production, and for the production of flavorous peptides and amino acids, the proteolytic ability of lactic acid bacteria is of crucial importance for reliable dairy product quality. In view of this importance, considerable research

  12. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology...

  13. Filamentous bacteria transport electrons over centimetre distances

    DEFF Research Database (Denmark)

    Pfeffer, Christian; Larsen, Steffen; Song, Jie;

    2012-01-01

    across centimetre-wide zones. Here we present evidence that the native conductors are long, filamentous bacteria. They abounded in sediment zones with electric currents and along their length they contained strings with distinct properties in accordance with a function as electron transporters. Living...

  14. Bacteria in ice may record climate change

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ To many people, bacteria and climate change are like chalk and cheese: the srnallest creature versus one of the biggest phenomena on Earth. Not really.Scientists with the CAS Institute of Tibetan Plateau Research (ITP) and coworkers recently reported that small bugs deposited in ice and snow might tell how our climate has been changing.

  15. [Innovative treatments for multidrug-resistant bacteria].

    Science.gov (United States)

    Pierre, Tattevin; Aurélien, Lorleac'h; Matthieu, Revest

    2014-03-01

    The spread of multidrug-resistant bacteria has accelerated sharply in the last decade. According to the World Health Organization they are responsible for an estimated 25 000 deaths in Europe each year. In addition, few new antibiotics are under development, raising the spectrum of a return to the "pre-antibiotic era". Non antibiotic antibacterial agents have recently attracted renewed interest. The most promising candidates are: i) phages (bacteria-infecting viruses) have been widely used in Eastern European countries since the 1930s but come up against logistic and regulatory obstacles due to the evolutionary nature of these biologic agents, while convincing clinical data are lacking; ii) bacteriocines are smallantibacterialpeptidesproducedby numerous bacteria; some have a rapid bactericidal effect, good tolerability, and a limited impact on the commensal flora; however, clinical use of bacteriocines is complicated by their fragility, poor penetration, and substantial risk of resistance selection ; iii) antisense oligonucleo tides act by inactivating genes through specific interaction with a complementary DNA or RNA fragment, potentially allowing specific inhibition of selected bacterial virulence factors. However, this therapeutic class may be more suitable for viral or genetic diseases than for multidrug-resistant bacterial infections, owing to the difficulty of delivering them inside bacteria. PMID:26427289

  16. Collective Sensing-Capacity of Bacteria Populations

    CERN Document Server

    Einolghozati, Arash; Fekri, Faramarz

    2012-01-01

    The design of biological networks using bacteria as the basic elements of the network is initially motivated by a phenomenon called quorum sensing. Through quorum sensing, each bacterium performs sensing the medium and communicating it to others via molecular communication. As a result, bacteria can orchestrate and act collectively and perform tasks impossible otherwise. In this paper, we consider a population of bacteria as a single node in a network. In our version of biological communication networks, such a node would communicate with one another via molecular signals. As a first step toward such networks, this paper focuses on the study of the transfer of information to the population (i.e., the node) by stimulating it with a concentration of special type of a molecules signal. These molecules trigger a chain of processes inside each bacteria that results in a final output in the form of light or fluorescence. Each stage in the process adds noise to the signal carried to the next stage. Our objective is ...

  17. DISTRIBUTION OF PLASMIDS IN GROUNDWATER BACTERIA

    Science.gov (United States)

    Bacteria isolated from groundwater aquifer core materials of pristine aquifers at Lula and Pickett, Oklahoma, and from a site with a history of aromatic hydrocarbon contamination and natural renovation located at Conroe, Texas, were screened for the presence of plasmid Deoxyribon...

  18. Radiographic markers - A reservoir for bacteria?

    International Nuclear Information System (INIS)

    Introduction: Amongst the most frequently handled objects in the radiology department are radiographic markers. They are personal accessories used with every patient, and are kept in the radiographers pockets when not utilised. Upon enquiry it was discovered that many radiographers disregarded the potential of these accessories to become a vector for cross-contamination thus never or rarely clean them. The aims of this study were therefore to identify if radiographic markers are a reservoir for bacteria and to establish an effective cleaning method for decontaminating them. Methodology: 25 radiographers/student radiographers were selected for this study. Swabbing of their markers prior and post cleaning took place. The microbiology laboratory subsequently analyzed the results by quantifying and identifying the bacteria present. The participants also completed a closed questionnaire regarding their markers (e.g. frequency of cleaning and type of marker) to help specify the results gained from the swabbing procedure. Results: From the sample swabbed, 92% were contaminated with various organisms including Staphylococcus and Bacillus species, the amount of bacteria present ranged from 0 to >50 CFU. There were no significant differences between disinfectant wipes and alcohol gel in decontaminating the markers. Both successfully reduced their bacterial load, with 80% of the markers post cleaning having 0 CFU. Conclusion: The results indicated that radiographic markers can become highly contaminated with various organisms thus serve as a reservoir for bacteria. In addition, the markers need to be cleaned on a regular basis, with either disinfectant wipes or alcohol gel to reduce their bacterial load.

  19. The effects of bacteria on crystalline rock

    International Nuclear Information System (INIS)

    Many reactions involving inorganic minerals at water-rock interfaces have now been recognized to be bacterially mediated; these reactions could have a significant effect in the excavation of vaults for toxic and radioactive waste disposal. To investigate the role that bacteria play in the natural aqueous environment of crystalline rock the microbial growth factors of nutrition, energy and environment are described. Microbial activity has been investigated in Atomic Energy of Canada's Underground Research Laboratory (URL), situated in the Archean granitic Lac du Bonnet Batholith, Winnipeg, Manitoba. Faults, initiated in the Early Proterozoic, and later-formed fractures, provide ground-water pathways. Planktonic bacteria, free-swimming in the groundwater, have been observed in over 100 underground borehole samples. The number of bacteria varied from 103 to 105 mL-1 and appeared to decrease with depth and with increased salinity of the water. However, in the natural environment of deep (100-500 m) crystalline rocks, where nutrition is limited, formation of biofilms by sessile bacteria is a successful survival strategy. Natural biofilms at the URL and biofilms grown in bioreactors have been studied. The biofilms can accumulate different elements, depending upon the local environment. Precipitates of iron have been found in all the biofilms studied, where they are either passively accumulated or utilized as an energy source. Within the biofilm active and extensive biogeochemical immobilization of dissolved elements is controlled by distinct bacterial activities which are sufficiently discrete for hematite and siderite to be precipitated in close proximity

  20. Bioluminescent bacteria: lux genes as environmental biosensors

    OpenAIRE

    Nunes-Halldorson Vânia da Silva; Duran Norma Letícia

    2003-01-01

    Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in env...

  1. DETOXIFICATION BY MAGNETOTACTIC BACTERIA IN SEDIMENTS

    Science.gov (United States)

    The ability of certain bacteria to take up iron in the environment and biosynthesis magnetic materials such as magnetite (Fe3O4) and greigite (Fe3S4) has been recognized (Blakemore, 1982; Bazylinski and Frankel, 2000). Two different mechanisms, biologically induced mineralizat...

  2. Serpins in unicellular Eukarya, Archaea, and Bacteria:

    DEFF Research Database (Denmark)

    Roberts, T.H.; Hejgaard, Jørn; Saunders, N.F.W; Cavicchiolo, R.; Curmi, P.M.G

    2004-01-01

    , where serpins were found in only 4 of 13 genera, and Bacteria, in only 9 of 56 genera. The serpins from unicellular organisms appear to be phylogenetically distinct from all of the clades of higher eukaryotic serpins. Most of the sequences from unicellular organisms have the characteristics of...

  3. Molecular evolution in bacteria: cell division

    OpenAIRE

    Trevors J.T.

    1998-01-01

    Molecular evolution in bacteria is examined with an emphasis on the self-assembly of cells capable of primitive division and growth during early molecular evolution. Also, the possibility that some type of encapsulation structure preceeded biochemical pathways and the assembly of genetic material is examined. These aspects will be considered from an evolutionary perspective.

  4. Emerging Plant Pathogenic Bacteria and Global Warming

    Science.gov (United States)

    Several bacteria, previously classified as non-fluorescent, oxidase positive pseudomonads, Ralstonia, Acidovorax, and Burkholdria have emerged as serious problems world-wide. Perhaps the most destructive is R. solanacearum (RS), a soilborne pathogen with a very wide host range. RS race 3, biovar 2...

  5. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T; Altermann, E; Arigoni, F; Bolotin, A; Breidt, F; Broadbent, J; Cano, R; Chaillou, S; Deutscher, J; Gasson, M; van de Guchte, M; Guzzo, J; Hartke, A; Hawkins, T; Hols, P; Hutkins, R; Kleerebezem, M; Kok, J; Kuipers, O; Maguin, E; McKay, L; Mills, D; Nauta, A; Overbeek, R; Pel, H; Pridmore, D; Saier, M; van Sinderen, D; Sorokin, A; Steele, J; O'Sullivan, D; de Vos, W; Weimer, B; Zagorec, M; Siezen, R

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in ferment

  6. Drug efflux proteins in multidrug resistant bacteria

    NARCIS (Netherlands)

    vanVeen, HW; Konings, WN

    1997-01-01

    Bacteria contain an array of transport proteins in their cytoplasmic membrane. Many of these proteins play an important role in conferring resistance to toxic compounds. The multidrug efflux systems encountered in prokaryotic cells are very similar to those observed in eukaryotic cells. Therefore, a

  7. Identification of bacteria using mass spectrometry techniques

    Czech Academy of Sciences Publication Activity Database

    Krásný, Lukáš; Hynek, R.; Hochel, I.

    2013-01-01

    Roč. 353, NOV 2013 (2013), s. 67-79. ISSN 1387-3806 R&D Projects: GA ČR GAP503/10/0664 Institutional support: RVO:61388971 Keywords : Mass spectrometry * Bacteria * Identification Subject RIV: EE - Microbiology, Virology Impact factor: 2.227, year: 2013

  8. Chitinolytic bacteria of the mammal digestive tract

    Czech Academy of Sciences Publication Activity Database

    Šimůnek, Jiří; Hodrová, Blanka; Bartoňová, H.; Kopečný, Jan

    2001-01-01

    Roč. 46, č. 1 (2001), s. 76-78. ISSN 0015-5632 R&D Projects: GA ČR GA525/00/0984; GA AV ČR KSK5052113 Keywords : chitinolytic bacteria Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.776, year: 2001

  9. Comparative activity of ciprofloxacin against anaerobic bacteria.

    OpenAIRE

    Sutter, V L; Kwok, Y Y; Bulkacz, J

    1985-01-01

    The in vitro activity of ciprofloxacin was assessed against 362 strains of anaerobic bacteria and compared with that of cefoxitin, clindamycin, metronidazole, and mezlocillin. Only 31% of the strains tested were susceptible to ciprofloxacin. The other agents were active against most of the strains tested.

  10. Probiotic Bacteria May Become Dormant during Storage

    OpenAIRE

    Lahtinen, Sampo J.; Gueimonde, Miguel; Ouwehand, Arthur C; Reinikainen, Johanna P.; Salminen, Seppo J.

    2005-01-01

    The determination of bacterial viability in probiotic products is of economic, technological, and clinical significance. We compared four methods to enumerate three Bifidobacterium strains in fermented oat products during storage. A subpopulation of nonculturable cells retained a functional cell membrane typical of viable cells, indicating that probiotic bacteria become dormant during storage.

  11. Freeze-drying of lactic acid bacteria.

    Science.gov (United States)

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery. PMID:25428024

  12. The interaction of bacteria and metal surfaces

    International Nuclear Information System (INIS)

    This review discusses different examples for the interaction of bacteria and metal surfaces based on work reported previously by various authors and work performed by the author with colleagues at other institutions and with his graduate students at CEEL. Traditionally it has been assumed that the interaction of bacteria with metal surfaces always causes increased corrosion rates ('microbiologically influenced corrosion' (MIC)). However, more recently it has been observed that many bacteria can reduce corrosion rates of different metals and alloys in many corrosive environments. For example, it has been found that certain strains of Shewanella can prevent pitting of Al 2024 in artificial seawater, tarnishing of brass and rusting of mild steel. It has been observed that corrosion started again when the biofilm was killed by adding antibiotics. The mechanism of corrosion protection seems to be different for different bacteria since it has been found that the corrosion potential Ecorr became more negative in the presence of Shewanella ana and algae, but more positive in the presence of Bacillus subtilis. These findings have been used in an initial study of the bacterial battery in which Shewanella oneidensis MR-1 was added to a cell containing Al 2024 and Cu in a growth medium. It was found that the power output of this cell continuously increased with time. In the microbial fuel cell (MFC) bacteria oxidize the fuel and transfer electrons directly to the anode. In initial studies EIS has been used to characterize the anode, cathode and membrane properties for different operating conditions of a MFC that contained Shewanella oneidensis MR-1. Cell voltage (V)-current density (i) curves were obtained using potentiodynamic sweeps. The current output of a MFC has been monitored for different experimental conditions

  13. Label-Free Applications of SERS for Bacteria Analysis

    OpenAIRE

    Zhou, Haibo

    2014-01-01

    In the first part, we report on surface-enhanced Raman scattering (SERS) for living bacteria detection in drinking water by employing a synthesis of silver nanoparticles coating the cell wall of bacteria (Bacteria@AgNPs). In the second part of this thesis, we present a label-free SERS detection of bacteria on microarray at single cell level. In the third part of this thesis, we successfully counted live and dead bacteria with Bacteria@AgNPs method by SERS mapping technique.

  14. Antibacterial activity of silver-killed bacteria: the "zombies" effect

    Science.gov (United States)

    Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

    2015-04-01

    We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

  15. Obtención de un mejorador de suelos como subproducto de la digestión anaerobia de desechos orgánicos en el TEC Obtention of a soil improver as subproduct from the anaerobic digestion of organic residues at the Technological Institute of Costa Rica

    Directory of Open Access Journals (Sweden)

    Margie Faith Vargas

    2012-11-01

    Full Text Available El tratamiento anaerobio de los desechos orgánicos permite obtener efluentes con propiedades biofertilizantes, además de biogás para la generación de energía renovable. El objetivo del presente estudio fue evaluar una mezcla de los efluentes de dos biodigestores a escala en elTEC para determinar su potencial uso como bioabono. Se analizó la composición química y se encontró que el proceso de biodigestión aumentó el contenido de nutrientes. Se determinó la calidad microbiológica y se observó una disminución en el recuento de coliformes fecales pero no se alcanzó la concentración bacteriana mínima para garantizar una aplicación inocua a los cultivos de consumo directo. Por otra parte, se realizaron ensayos en invernadero, aplicando tres tratamientos al cultivo de lechuga (Lactuca sativa. El primero consistió en fertilizar el cultivo con la mezcla de efluentes concentrada, el segundo con la mezcla diluida al 50% y el tercero con un fertilizante químico. Se analizó la altura de las plantas, el número de hojas, el peso fresco y el peso seco. Se encontraron diferencias estadísticamente significativas para las tres primeras variables, pero no para la última. Se concluyó que el fertilizante químico produjo mejores resultados en el corto plazo, y que la aplicación del efluente diluido al 50% fue más efectiva que al 100%. Se recomienda utilizar los efluentes de los biodigestores a escala del TEC como mejoradores de suelos, tomando las medidas necesarias para garantizar su inocuidad.Anaerobic treatment of organic wastes generates effluents with biofer tilizer proper ties, besides biogas for renewable energy production. The purpose of this research was to evaluate a mixture of effluents obtained from two small scale biodigesters at the TEC, with the purpose of determining its potential use as biofertilizer. We analyzed the chemical composition and found an increase in the nutrient content of the effluents after biodigestion. We

  16. Actividad in vitro de furvina frente a bacterias Gram negativas multirresistentes

    Directory of Open Access Journals (Sweden)

    Yeny Morales-Moreno

    2014-01-01

    Full Text Available Actualmente existe una crisis global en el tratamiento de las enfermedades infecciosas debido a microorganismos resistentes a la mayoría de los agentes antimicrobianos convencionales. Desafortunadamente, no han sido desarrollados nuevas clases de estos compuestos antibacterianos activos frente a bacterias Gram negativas multirresistentes en los últimos años. Esta situación llevó a que muchos trabajos de investigación estén encaminados a la búsqueda de nuevas sustancias biológicamente activas. Los objetivos del presente estudio consistieron en aislar e identificar bacterias Gram negativas resistentes a múltiples fármacos, así como evaluar la actividad antibacteriana in vitro de furvina frente a ellas. La identificación se efectuó mediante métodos bioquímicos convencionales. La resistencia a los agentes antibacterianos se determinó mediante el método de difusión en agar y la actividad in vitro se evaluó cuantitativamente mediante macrodilución en caldo según los criterios del Instituto de Estándares de Laboratorios Clínicos. Fueron identificadas de 62 cepas multirresistentes de ocho géneros. El 59,67 % de ellas perteneció al género Acinetobacter y una cepa de Enterobacter cloacae fue resistente a meropenem con concentración mínima inhibitoria (CMI mayor que 4 μg/mL. El 100 % de las cepas de Acinetobacter spp. multirresistentes presentó CMI en el intervalo de 8 a 32 μg/mL frente a furvina y el 30 % de ellas, mostró resistencia a meropenem con valores de CMI entre 16 y 256 μg/mL. Finalmente, furvina mostró buena actividad antibacteriana in vitro frente a todas las bacterias Gram negativas multirresistentes evaluadas.

  17. Bacteria in Crude Oil Survived Autoclaving and Stimulated Differentially by Exogenous Bacteria

    OpenAIRE

    Gong, Xiao-Cui; Liu, Ze-Shen; Guo, Peng; Chi, Chang-Qiao; Chen, Jian; Wang, Xing-Biao; Tang, Yue-Qin; Wu, Xiao-Lei; Liu, Chun-Zhong

    2012-01-01

    Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR). However, it is not entirely clear if “endogenous” bacteria (e.g., spores) in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the “exogenous” bacterial strains. To test this, we inoculated autoclaved crude oil medium with six ...

  18. Lactic acid bacteria from fresh fruit and vegetables as biocontrol agents of phytopathogenic bacteria and fungi

    OpenAIRE

    Trias Mansilla, Rosalia; Bañeras Vives, Lluís; Montesinos Seguí, Emilio; Badosa Romañó, Esther

    2008-01-01

    This study evaluated the efficacy of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol agents against the phytopathogenic and spoilage bacteria and fungi, Xanthomonas campestris, Erwinia carotovora, Penicillium expansum, Monilinia laxa, and Botrytis cinerea. The antagonistic activity of 496 LAB strains was tested in vitro and all tested microorganisms except P. expansum were inhibited by at least one isolate. The 496 isolates were also analyzed for the inhibit...

  19. Spray drying of dairy bacteria: New opportunities to improve the viability of bacteria powders

    OpenAIRE

    Dolivet, Anne; Mejean, Serge; Hervé, C.; Jeantet, Romain

    2013-01-01

    The most frequently used technique for dehydration of dairy bacteria is freeze drying. Of the other possible preservation techniques used in the dairy industry to produce large amounts of dairy ingredients at commercially viable processing costs, spray drying is one of the main processing tools and the cost is 10 times lower than that of freeze drying. In this work, some examples are presented for different species of dairy bacteria with respect to spray-drying processes (as an alternative ap...

  20. Assessment of the Levels of Airborne Bacteria, Gram-Negative Bacteria, and Fungi in Hospital Lobbies

    OpenAIRE

    Dong-Uk Park; Jeong-Kwan Yeom; Won Jae Lee; Kyeong-Min Lee

    2013-01-01

    Aims: We assessed the levels of airborne bacteria, Gram-negative bacteria (GNB), and fungi in six hospital lobbies, and investigated the environmental and hospital characteristics that affected the airborne microorganism levels. Methods: An Andersen single-stage sampler equipped with appropriate nutrition plate agar was used to collect the samples. The three types of microorganisms were repeatedly collected at a fixed location in each hospital (assumed to be representative of the entire hospi...

  1. Estudios pioneros en torno al origen del lenguaje natural

    Directory of Open Access Journals (Sweden)

    Martínez Contreras, Jorge

    2011-02-01

    Full Text Available It has being an ancient desire to ask apes what their natural lives are. De la Mettrie was the first to propose, in the 18th C., that the sign language of deaf adults could be used with them since they do not speak. We enhance here some of the pioneering projects of the two strategies for this endeavor: the use of ASL and the utilization of lexigrams and computers. Besides the ancient communicative quest with them, the evolutionist’s perspective has seen in these studies a way to find out how the natural language (NL emerged in hominids. If it is clear that apes do no possess totally the NL, the linguistic turn in primatology has left way, as in philosophy, to more complex field and laboratory cognitive studies of less anthropocentric nature.

    Tratar de hablar con los simios y preguntarles cosas sobre su vida natural es un viejo deseo. De la Mettrie propone, en el s. XVIII, que se les enseñe el lenguaje de los sordos en vista de que no pueden hablar. Resaltamos aquí algunos estudios pioneros en relación con las dos estrategias llevadas a cabo para tratar de hablar con los simios: el uso del lenguaje americano de sordos (ASL y el de los lexigramas y computadoras. Además del viejo interés interrogativo humano hacia ellos, la perspectiva evolucionista ha visto en estos estudios un medio de investigar cómo surgió el lenguaje natural (LN en homínidos. Si queda claro que los simios no poseen totalmente el LN, el giro lingüistico en primatología ha cedido, como en filosofía, el paso a estudios cognitivos más complejos, de campo y de laboratorio, de orientación menos antropomórfica.

  2. Estudio del sistema simbiótico AR Pavonis

    Science.gov (United States)

    Quiroga, C.; Brandi, E.; Ferrer, O.; García, L.; Barbá, R.

    Se presenta un estudio espectroscópico y polarimétrico de la binaria eclipsante AR Pavonis a partir de observaciones obtenidas con el telescopio de 2.15 m. del CASLEO (San Juan). El estudio de la naturaleza del sistema se realizó a través del análisis de algunos espectros reunidos entre los años 1990 y 1995 y de datos polarimétricos correspondientes al intervalo 1995 y 1997. El análisis espectroscópico indica que AR Pav está compuesta por una gigante roja M3.7 y una componente caliente compacta, con una temperatura mayor a 90000 K y una luminosidad del orden de 500Lsolar. A lo largo del período orbital, las variaciones observadas en flujo y en velocidades radiales, reflejan que las emisiones permitidas se forman en una región que rodea la componente caliente. El estudio de la polarización lineal de AR Pav indica que además de una componente interestelar, existe una componente intrínseca del sistema que varía temporalmente y con la longitud de onda de la luz polarizada. El distinto comportamiento del grado de polarización y del ángulo de posición observado en fases diferentes, sugiere que distintos mecanismos pueden estar actuando, dependiendo de la región de scattering observado a lo largo de la línea de la visual.

  3. ESTUDIOS DE VISITANTES A MUSEOS (VISITOR STUDIES IN MUSEUMS

    Directory of Open Access Journals (Sweden)

    Rodríguez Sánchez Keilyn

    2011-08-01

    Full Text Available Resumen:Este artículo ofrece un estudio bibliográfico en torno a las investigaciones sobre la relación entre la museografía y sus visitantes. El objetivo central de este documento consiste en elaborar una clasificación de esos estudios en programas de investigación de manera que sirva de punto de partida para la construcción de una pedagogía del Museo. Para este fin, se utiliza la propuesta de Schulman, sobre tipificación de estudios en programas de investigación y, al respecto, se plantean cuatro tipos: investigaciones centradas en lo museográfico, investigaciones centradas en el comportamiento museal, investigaciones centradas en la interacción dispositivo-visitantes y las investigaciones centradas en la evaluación museográfica. Se concluye que los resultados de investigación de estos programas, junto con el conocimiento de las técnicas de diseño y a la teoría educativa, serían la base central de un planteamiento sobre pedagogía museológica.Abstract: This article is a bibliographical research study of museography and the relationship of visitors to them. The main objective of this paper is to develop a classification system of these studies of research programs which serve as a starting point for systematizing the pedagogics of the museum. The author's fourfold typology of research programs builds on Schulman’s (1989 program research concept: museography centered research, museum behavior centered research, museum interaction (visitor-exhibition centered research, and museum evaluation centered research. The article reaches the conclusion that the research findings of these programs along with knowledge of design techniques and educational theory will serve as the primary basis for a Museology pedagogy proposal.

  4. Estudio del comportamiento de los puentes tipo pony colgantes

    OpenAIRE

    Takeuchi Tam, Caori Patricia; León, Beatriz Elena; González, Mario Alberto

    2010-01-01

    En el país se encuentran numerosos puentes de paso a través intermedio colgantes. En este artículo se presentan la metodología y las conclusiones obtenidas en un estudio sobre el comportamiento de este tipo de puentes para las cargas existentes durante su proceso de construcción y puesta en servicio, mediante la constrastación entre modelos físicos y matemáticos. Igualmente, se estudió para estos modelos la estabilidad lateral.

  5. ESTUDIO CINEANTROPOMÉTRICO DEL JUGADOR DE TENIS ADOLESCENTE

    OpenAIRE

    Gema Torres Luque; Fernando Alacid Cárceles; Carmen Ferragut Fiol; Carmen Villaverde Gutiérrez

    2006-01-01

    El propósito de este estudio fue aproximarse al perfil cineantropométrico de jugadores de tenis de edad adolescente. Para ello se seleccionaron 75 jugadores de tenis (47 varones y 26 mujeres) a los cuales se les determinó el perfil antropométrico, composición corporal y somatotipo, mostrando a su vez las diferencias en cuanto al género. Todas las valoraciones se realizaron siguiendo las recomendaciones del Grupo Español de Cineantropometría, los tenistas fueron evaluados a la misma hora del d...

  6. Estudios de impacto ambiental y sus tendencias en colombia

    OpenAIRE

    Hernández, Luis Alfredo

    2011-01-01

    Un Estudio de Impacto Ambiental (ElA) constituye una herramienta de planificación, ordenamiento y toma de decisiones de las acciones del hombre y/o la naturaleza para preservar o mantener una oferta de bienes naturales para el desarrollo sostenible de la sociedad. El EIA busca identificar, describir, evaluar y controlar los efectos que las acciones del hombre tengan sobre el medio, incluyendo al hombre como el agente principal que induce cambios sobre el ambiente. Antes de 1993 los EIA se car...

  7. INTELIGENCIA Y RENDIMIENTO DEPORTIVO: UN ESTUDIO SOBRE LA INTELIGENCIA EMOCIONAL

    OpenAIRE

    Gerardo Araya Vargas; Wálter Salazar Rojas

    2001-01-01

    Este estudio tuvo el propósito de determinar la correlación entre los índices de inteligencia tradicional (razonamiento analógico, C. I.) e inteligencia emocional (C.E.) con el rendimiento deportivo. Participaron 10 basketbolistas, entre los 17 y 25 años (media = 20.1 años), todas mujeres. Se les aplicó pruebas de C. I. (Raven) y de C. E. (Goleman) y luego se sometió a los sujetos a dos pruebas de precisión (tiro libre y tiro de tres puntos) y posteriormente el entrenador evaluó mediante la E...

  8. Decretos leyes y jurisdición constitucional. Estudios comparados.

    OpenAIRE

    Camargo, Maria Auxiliadora Castro e

    2010-01-01

    [ES] El presente trabajo de investigación tiene como objetivo fundamental investigar las semejanzas y diferencias existentes entre las categorías normativas que se presentan bajo la denominación general de "Decretos-leyes", también denominadas por las Constituciones: "Medidas Provisórias" (Brasil); "Disposiciones Legislativas Provisionales" (España); "Provvedimenti Provvisori con forza di legge" (Italia) y "Decretos-leis" (Portugal). En su alcance general, el estudio también pretende dar a co...

  9. Estudio de la respuesta piezoeléctrica en PVDF

    OpenAIRE

    Córdoba Casado, Luis Miguel

    2013-01-01

    Los polímeros piezoeléctricos son ampliamente usados en la actualidad para múltiples aplicaciones como sensores y actuadores. En este proyecto fin de carrera se realiza un estudio de la respuesta piezoeléctrica del PVDF, se escogió el PVDF tanto por su excelente respuesta piezoeléctrica como por su buena procesabilidad. Para caracterizar la respuesta piezoeléctrica se desarrollan y optimizan tres montajes experimentales. El experimento vertical en el que dejamos caer verticalmente distintas b...

  10. La arquitectura de museos en Colombia, un caso de estudio

    OpenAIRE

    Tamasco Torres, Gisela

    2013-01-01

    El presente trabajo de orden conceptual aborda el tema de la arquitectura de los museos en Colombia. Se ha realizado un recorrido por algunos de los museos del país cuya edificación ha contado con un diseño arquitectónico, realizado específicamente para albergar la actividad museal. El caso de estudio se centra en el Museo de Arte Moderno de Bogotá, por la relevancia de estar ubicado en la ciudad capital, por su colección de arte contemporáneo representativo de la N...

  11. Técnicas de diafanización: estudio comparativo

    OpenAIRE

    Greco Machado, Y.; García Molina, J.A.; Bueno Martínez, R.; Manzanares Céspedes, María Cristina; Lozano de Luaces, Vicente

    2008-01-01

    Las técnicas de diafanización dental, han sido frecuentemente empleadas para evaluar diferentes aspectos anatómicos y endodóncicos, son muy variables y se utilizan principalmente con objetivos docentes. El propósito de éste estudio consistió en comparar la transparencia y dureza de la dentina entre grupos de dientes diafanizados mediante diferentes técnicas y comparar además su eventual idoneidad para realizar técnicas endodóncicas. Las técnicas de diafanización empleadas fueron: la técnica d...

  12. Estudio del metabolismo energético de Geotrichum klebahnii

    OpenAIRE

    Baruque, Diego Jorge

    2003-01-01

    Sumario: Introducción Geotrichum klebahnii Estudio del crecimiento de G. klebahnii Balances de materia en cultivo Cultivos batch Cultivos continuos Análisis de Flujos Metabólicos (AFM) Materiales y métodos Cepa Mantenimiento de la cepa Medios de cultivo Cultivos en batch Cultivos continuos Análisis Matricial Resultados y discusión Cultivo batch Cultivo continuo Análisis de Flujos Metabólicos (AFM) Modelo Metabólico sen...

  13. UNIDADES DE EMPRENDIMIENTO BAJO UN ESTUDIO DE EFICIENCIA RELATIVA

    OpenAIRE

    GLORIA ISABEL RODRÍGUEZ LOZANO; ORLANDO TARAZONA MORALES

    2015-01-01

    Este artículo presenta un análisis comparativo de la eficiencia relativa de un grupo de Unidades de Emprendimiento (UE) ubicadas en la ciudad de Bogotá, utilizando Data Envelopment Analysis (DEA). Con base en la información obtenida de las UE estudiadas se definieron las entradas y sali - das, se generaron los diferentes submodelos, la Frontera Eficiente para cada uno y se analizaron los factores que determinaron esa condición. El presente estudio termina planteando la posibilidad de adel...

  14. Síndrome de Down: Estudio de un Caso.

    OpenAIRE

    Amigo Soto, Elisabet

    2013-01-01

    El trabajo trata de un estudio de caso que tiene por objeto conocer las características generales que conlleva el Síndrome de Down, deteniéndonos especialmente en las posibilidades que presenta este tipo de alumnado en el ámbito educativo. Del mismo modo, se hace justificación de por qué el maestro de educación infantil no especialista en educación especial debe contar con la formación suficiente para ofrecer a estos sujetos una enseñanza de calidad que desarrolle al máximo sus potencialidade...

  15. Cultura organizacional en una empresa estatal colombiana: estudio de caso

    OpenAIRE

    Diana Marcela Suárez Pachón; María Isabel Parra Triviño; Angie Margarita Herrera Quintana; María Claudia Peralta Gómez

    2013-01-01

    La presente investigación se centra en la descripción de las características de la cultura organizacional de una empresa estatal colombiana, basados en la propuesta teórica de Edgar Schein. Por ello su alcance se restringe a una entidad particular y se presenta como un estudio de caso, en el que se propone un método de indagación de la cultura, que puede ser utilizado para otras investigaciones. El diseño de la investigación es de carácter descriptivo, de corte cualitativo, en el que se utili...

  16. Estudios citogenéticos en Philodryas chamissonis (Serpentes: colubridae)

    OpenAIRE

    Navarro, J.; Iturra, P.; Moreno, R.; A. Veloso

    1987-01-01

    Estudios cromosómicos previos en Philodryas se han realizado en P. olferaii, P. aestivus y P. patagoniensis. Todas presentan un cariotipo 2n=36, con 16 macrocromosomas (M) y 20 microcromosomas (m). En Chile el género está representado por P. chamissonis, aislada geográficamente de sus congéneres. El objetivo de este trabajo es describir su cariotipo y aportar con marcadores cromosómicos, a futuras comparaciones interespecíficas, orientadas a precisar las relaciones taxofiléticas de esta espec...

  17. Los estudios de posgrado en nuestro país

    OpenAIRE

    Chicote, Gloria

    2008-01-01

    Intentaré trazar el estado de los estudios de posgrado en nuestro país a partir de un análisis de su historia reciente. Llamo historia reciente a la última década, la década que va desde mediados de los 90 hasta el presente. Y en función de esa historia reciente propongo hacer una evaluación de cómo y en qué estamos, para concluir con proyecciones y posibles lineamientos hacia el futuro. (Párrafo extraído del texto a modo de resumen)

  18. Estudio del patrón respiratorio en pacientes ancianos

    OpenAIRE

    Tellez Gabriel, Juan Pablo; Herrera, Sergio; Benito Vales, Salvador; Giraldo Giraldo, Beatriz

    2014-01-01

    La clínica relacionada con los pacientes ancianos, refleja una elevada incidencia de enfermedades de origen cardíaco y respiratorio. Alteraciones en el patrón respiratorio como son la respiración periódica (PB) y la respiración Cheyne-Stokes (CSR) pueden estar relacionadas con la insuficiencia cardíaca crónica (ICC). En este estudio se propuso caracterizar estos patrones respiratorios a partir de la envolvente de la señal de flujo respiratorio, aplicando técnicas de análisis frecuencial y de ...

  19. Estudio de factibilidad para un calzado personalizable femenino

    OpenAIRE

    Durán Pimienta, Oscar Adrián; Jaimes Santamaría, Juan Camilo

    2011-01-01

    El presente documento describe el proceso de investigación realizado por dos estudiantes de la Universidad EAFIT sobre la factibilidad de desarrollar un calzado personalizable femenino, en este proceso se llevaron a cabo diferentes estudios primarios con el fin de poseer una contextualización sobre la situación económica tanto del sector calzado, cuero y sus manufacturas, como del país -- Además se realizó una investigación sobre los diferentes procesos necesarios para la realizac...

  20. Anorexia nerviosa en adolescentes:un estudio comparativo

    OpenAIRE

    Vásquez, Rafael; Angel, Luis Alberto; Moreno, Nancy; García, Jenny; Calvo, José Manuel

    2010-01-01

    Objetivo: analizar algunas variables asociados con AN en una serie clínica de pacientes colombianos, comparándolos con jóvenes de similar edad, sexo y nivel cultural. Método: Es un estudio de casos y controles en adolescentes de Santafé de Bogotá. Se evaluaron diez pacientes con Anorexia Nerviosa, según el DSM-IV y diez controles emparejados por edad y sexo, a los cuales se les aplicaron una serie de encuestas y un instrumento específico de historia clínica. Resultados: Era el primer episodio...

  1. El pensamiento del experto como objeto de estudio

    OpenAIRE

    Palacios, Analía Mirta; Villar, Claudia Mariela

    1996-01-01

    Existe un renovado interés por el estudio de la naturaleza de los procesos creativos. Ilustraciones de este interés pueden hallarse por ejemplo en los trabajos de Gardner (1995) sobre as mentes creativas, los de Wertheimer (1945) sobre Einstein, los de Gruber (1981,1984) y Piskoppel (1985) sobre Darwin, y los de Vidal (1984) sobre la evolución de las ideas de Piaget (Cfr. Pozo, V. 1994). Si bien la experticia no puede considerarse como equivalente al talento creativo, en general se reconoce q...

  2. Cuidadores de Cartagena y su contexto de cuidado: estudio comparativo

    OpenAIRE

    Amparo Montalvo-Prieto; Inna Elida Flórez-Torres

    2009-01-01

    Objetivo: comparar las características sociodemográficas y de relación de cuidado de cuidadores de niños y adultos con enfermedades crónicas discapacitantes de Cartagena, Colombia. Método: estudio descriptivo, cuantitativo, de corte transversal. Se realizó un muestreo no probabilístico, por conveniencia, entre el 2006 y el 2007. Participaron 300 cuidadores: 98 de niños y 202 de adultos con enfermedades crónicas. Se utilizó la encuesta de caracterización de los cuidadores. Para describir las a...

  3. Estudio de soluciones Unified Threat Management (UTM) de libre acceso

    OpenAIRE

    León-Casas, Diego

    2016-01-01

    En este estudio se analizan las capacidades de protección de las soluciones UTM de libre acceso Endian Firewall Community, Sophos UTM Home Edition, y Untangle NG Firewall. Para ello se han creado diferentes escenarios simulando las amenazas básicas y avanzadas que un usuario doméstico o una pequeña empresa podrían encontrar para comprobar la eficacia de cada solución a la hora de detectar y bloquear los distintos ataques. Las pruebas revelan que Sophos es la que mejor resultados ha obtenid...

  4. Conceptos básicos sobre el estudio de paternidad

    OpenAIRE

    Marcela Lagos L; Helena Poggi M; Cecilia Mellado S

    2011-01-01

    El análisis de marcadores genéticos se ha convertido en una herramienta muy importante y ampliamente reconocida para la identificación de individuos y para el estudio de paternidad. Para esto se estudian distintas regiones del genoma humano que son altamente variables en la población y que permiten obtener el perfil genético y distinguir entre distintos individuos. La metodología que se utiliza es básicamente la misma en todo el mundo y consiste en el análisis de entre 13 a 15 marcadores. La ...

  5. Discapacidad visual y técnicas de estudio

    OpenAIRE

    Fernández, M

    2006-01-01

    Esta guía pretende ser una ayuda para los estudiantes ciegos o con grave discapacidad visual de la Educación Secundaria Obligatoria a la hora de comprender y recordar lo que estudian. El conocimiento y manejo de estrategias adecuadas de planificación a la hora de enfrentarse al estudio son fundamentales para estos estudiantes, por lo que estas propuestas son de gran utilidad a la hora de afrontar su trabajo en el aula y a conducirse con facilidad por los textos en sus distintos modos de prese...

  6. Aproximaciones proteómicas para el estudio del envejecimiento

    OpenAIRE

    Fanjul Hevia, Víctor

    2014-01-01

    La población mundial está envejeciendo progresivamente y la edad es el factor principal de riesgo de enfermedad cardiovascular (ECV), que a su vez es el principal problema de salud en países desarrollados. Aún no se conocen en profundidad los mecanismos moleculares que provocan el envejecimiento ni aquéllos que originan la ECV, y su estudio podría conducir hacia el desarrollo de estrategias preventivas o de terapias que alarguen significativamente la vida y mejoren su calidad. La progeria ...

  7. Estudio sobre turbina tubular de pequeña potencia

    OpenAIRE

    Saralegui, Gustavo David; Lopardo, Carlos E.; Sanmarco, Enrique Daniel; Liscia, Sergio O.; Suarez, Victor

    2011-01-01

    La energía eléctrica es una necesidad social básica, muchas veces ausente en comunidades relativamente alejadas de los principales centros urbanos. Es por ello que estudiar la posibilidad de dotar de energía a centros de escaso consumo mediante la construcción de pequeñas o medianas centrales hidroeléctricas resulta de gran interés, sobre todo donde se dispone de un recurso hídrico cercano, pasible de ser aprovechado. La necesidad de este estudio surgió en el marco de una coyuntura nacional, ...

  8. Estudios sobre la vegetacion del estado de Parana (Brasil meridional)

    OpenAIRE

    de Bolòs, Oriol; Cervi, Armando Carlos; Hatschbach, G. (Gert)

    1991-01-01

    BOLOS, O. DE, A.C. CERVI & G. HATSCHBACH (1991). Estudios sobre la vegetación del estado de Paraná (Brasil meridional). Collect. Bot. (Barcelona) 20: 79-182. Aportación al conocimiento de la vegetación del estado de Paraná en el Brasil meridional (Serra do Mar, Planaltos, valle del Iguacú). Se describen numerosas asociaciones vegetales agrupadas en las clases siguientes: Pistio-Eichhornietea (comunidades de cormófitas flotantes). Xyrido-Typhetea (vegetación herbácea helofítica). Polypodio-Til...

  9. ESTUDIOS COMPARADOS: UNA PROPUESTA METODOLÓGICA APLICADA

    OpenAIRE

    Castellanos Morales, Ethel Nataly

    2014-01-01

    Los estudios comparados otorgan herramientas de indiscutible valor para los investigadores jurídicos. Por eso pretendo mostrar las potencialidades y limitaciones de los análisis comparados enriquecidos con elementos discursivos. Esta metodología puede contribuir no sólo a la exploración de nuevos elementos surgidos de la misma, sino también a la creación de otras metodologías que se ajusten cada vez mejor a los diferentes objetos de estudió que hacen parte de la disciplina jurídica. Por eso e...

  10. Estudios de impacto ambiental en viaductos de gran longitud

    OpenAIRE

    Moya Matute, David

    2009-01-01

    El contenido de esta tesina forma parte de un proyecto concedido por el Ministerio de Educación y Ciencia en el año 2006 y coordinado entre el Departamento de Ingeniería de la Construcción de la UPC y el Departamento de Ingeniería Civil de la UCLM. El objeto de dicho proyecto de investigación es el estudio de la optimización de viaductos de gran longitud desde distintas vertientes, como son: estructural, plazo de ejecución, impacto ambiental, seguridad y salud, costes globales, et...

  11. Estudio de estabilidad de tabletas recubiertas de Secnidazol (500 mg)

    OpenAIRE

    Moya Mirabal, Antonio D.; Rodríguez Leyes, Eduardo Antonio; Márquez Conde, Tania; López Peláez, Bertha; Díaz Polanco, Iverlis

    2003-01-01

    Se realizó el estudio de estabilidad de secnidazol tabletas recubiertas de 500 mg, de producción nacional, y se determinó la fecha de vencimiento mediante el método de vida de estante. Para cuantificar el principio activo se empleó la cromatografía líquida de alta eficacia. En la técnica, debidamente validada, se empleó una columna de fase reversa RP-18, una mezcla metanol-agua (50:50, v/v) y detector ultravioleta con longitud de onda fijada a 320 nm. Se analizó el efecto de la humedad sobre ...

  12. Problemas epistemológicos en los estudios urbanos

    OpenAIRE

    Zuleta Ruíz, Fabián Beethoven

    1997-01-01

    El desdibujamiento de las prácticas y horizontes disciplinares justifica volver a plantear el argumento de la epistemología como tema para pensar las formaciones profesionales relacionadas con los estudios urbanos. La pregunta epistemológica afecta la actualidad teórica de las disciplinas que ordenan los universos de formación en el urbanismo y afecta los ordenes de sus lenguajes. Esta lectura epistemológica alberga la duda que en ella subyace un planteamiento de contraposición de métodos...

  13. Introducción Revista Estudios de Juventud

    OpenAIRE

    Naval, C.; Sádaba, Ch. (Charo)

    2005-01-01

    Los medios de comunicación buscan el modo de llegar a la audiencia joven, mientras ésta se muestra reacia a responder de un modo unívoco a las propuestas de las empresas de comunicación. Estudios recientes constatan, por ejemplo, que la juventud cada día lee menos la prensa, y que desciende su consumo de televisión. Junto a esto, padres y educadores están preocupados por la influencia que los medios pueden tener en su correcta formación.

  14. Método para el estudio de los movimientos oculares.

    OpenAIRE

    Mario Alfredo Parra

    2009-01-01

    Introducción: El análisis cuantitativo de los movimientos oculares en el dominio digital ha permitido incrementar la cantidad de información fisiológica que se puede extraer durante la interpretación de las señales oculográficas. En el terreno de las neurociencias, esto posibilita profundizar en el estudio de los mecanismos fisiopatológicos responsables de las afecciones oculomotoras. Objetivos: La finalidad de estos métodos de análisis es reducir el componente subjetivo que se introduce dura...

  15. Estudio de tratamientos pregerminativos en semilla de Fagus sylvatica L.

    OpenAIRE

    Bilbao Larringan, Enrique

    2010-01-01

    La propuesta para llevar a cabo un estudio sobre la reproducción sexual de la especie Fagus sylvatica, vino de la mano de Asociación de Viveristas Forestales de Euskadi, motivada principalmente por un previsible aumento en la demanda de plantas de dicha especie y por la heterogeneidad en la obtención del material vegetal de propagación (vecería). Esta vecería tan acusada, obliga a realizar un buen manejo en general de la semilla que se recoge, para poder tener material de repro...

  16. Un estudio eto-espacial con variables ambientales

    OpenAIRE

    Amenós i Vidal, Josep Maria; Tharrats i Pascual, Joan Josep

    1984-01-01

    La dinámica eto-espacial, en función de la variable ambiental, es un estudio desde el Enfoque paradigmático de la Psicología Ambiental. Se ha desarrollado en el foso de papiones sagrados (hamadryas) y anubis del Zoológico de Barcelona. Se han estudiado las posibles influencias del medio ambiente con respecto a la conducta, tanto en el contexto espacial como social. Se han utilizado conceptos como “unidad natural”, “behavior setting”, “nivel de movilidad”, etc. a nivel metodológico-observacion...

  17. Estudio psicosocial de las actividades de ocio en la adolescencia.

    OpenAIRE

    Torralba Jerez, Eva María

    2015-01-01

    La adolescencia supone un periodo de transición entre la niñez y la edad adulta, caracterizado por conflictos y tensiones. Los adolescentes presentan conductas que pueden considerarse de riesgo y que aumentan o disminuyen por la relación que mantienen con sus padres y grupo de iguales, así como por las actividades de ocio que realizan durante su tiempo libre y la percepción que tienen sobre ellas. El objetivo del presente estudio es conocer las pautas de uso de la lectura, compras, televisión...

  18. Adicción al trabajo: Estudio de un caso

    OpenAIRE

    Pallarés Barrés, Celia; Crouseilles Estrada, Carla Isabel; Ibáñez Gallén, Miriam; Lacueva Seguer, Ana Belén

    2015-01-01

    El objetivo de este proyecto es profundizar en el concepto de adicción al trabajo basándonos en un estudio retrospectivo de caso único, detectado inicialmente como adicto al trabajo (varón, 53 años) y mostrar así la fina línea existente entre la adicción al trabajo y otros conceptos afines. Para ello, hemos utilizado una metodología múltiple atendiendo a criterios cualitativos y cuantitativos. Los resultados obtenidos mediante el cuestionario DUWAS-10, indican que el sujeto pun...

  19. ESTUDIO SOBRE LA PERCEPCIONES Y LA EDUCACIÓN AMBIENTAL

    OpenAIRE

    Raúl Calixto Flores; Lucila Herrera Reyes

    2010-01-01

    La educación ambiental como un campo emergente de construcción de nuevas propuestas, demanda de otros campos de estudio, información para comprender el origen de los comportamientos ambientales desfavorables hacia el medio ambiente. Se asume que la forma en que la persona percibe y construye los problemas ambientales, no se sustenta, necesariamente, en una forma neutral de contemplar el mundo; estas percepciones y los sesgos que las llevan a privilegiar ciertos problemas por sobre otros con d...

  20. Estudio de resonancias magnéticas mediante redes

    OpenAIRE

    Duque López, Gabriel

    2015-01-01

    Persiguiendo los objetivos dados por la descripción formal del trabajo de fin de grado, la labor realizada ha sido dirigida hacia cuatro enfoques principales: el estudio teórico de las redes, la generación de redes funcionales a partir de datos de experimentos de resonancias magnéticas funcionales, el análisis de la topología de estas redes y el desarrollo de herramientas informáticas necesarias a esas tareas.

  1. Estudio densitom??trico computarizado de cromosomas humanos

    OpenAIRE

    Garc??a Lirola, Gracia

    1992-01-01

    El objetivo principal de este trabajo ha sido el estudio de las caracter??sticas cuantitativas de las diferentes bandas cromosomicas que constituyen el cariotipo humano. Para ello hemos realizado un an??lisis automatizado de las diferentes curvas de densidad cromosomica, bas??ndose este en la aplicaci??n sobre cada una de estas curvas de una serie de par??metros previamente dise??ados: altura, posici??n y anchura de los picos, diferencia de altura entre cada pico y sus valles adyacentes y pos...

  2. Kant, lecturas para el estudio de la desobediencia civil

    OpenAIRE

    Olmo Bau, Carlos S.

    2004-01-01

    En este artículo se realiza un peculiar recorrido por parte de la obra kantiana y de la de algunos conocidos lectores de ella, en el seno de una indagación sobre las formas colectivas de trasgresión de la legalidad. Y aunque a veces roce el diálogo crítico con esos textos, es fundamentalmente el reflejo de una búsqueda en la que ética, filosofía política y filosofía del derecho se entrecruzan: la de elementos para el estudio de ese peculiar delito llamado D...

  3. Inteligencia Emocional y Bienestar Subjetivo: un estudio en adolescentes

    OpenAIRE

    Andrés Cruz, Verónica

    2012-01-01

    Dissetenes Jornades de Foment de la Investigació de la FCHS (Any 2012) En el presente estudio se pretende conocer la relación existente entre la Inteligencia Emocional (IE) y el Bienestar Subjetivo (BS), para saber si los adolescentes con mayor Inteligencia Emocional muestran un mayor Bienestar Subjetivo. Para ello, se ha aplicado el test MSCEIT para medir la IE y el test EBP para medir el Bienestar Subjetivo, estos han sido aplicados a 40 alumnos/as que cursan primer c...

  4. Evaluación asistida por ordenador: estudio experimental

    OpenAIRE

    María José RODRÍGUEZ CONDE; Olmos Migueláñez, Susana

    2005-01-01

    A modo de continuación de la comunicación “Evaluación de aprendizaje a través de Internet: posibilidades y limitaciones” desarrollada en las I Jornadas, presentamos un estudio experimental sobre evaluación asistida por ordenador (Computer-Assisted Assessment); basándonos en un diseño experimental con tres grupos: dos experimentales y uno de control, con control pre-postest, aplicado en el curso académico 2004-05. El objetivo que perseguimos es demostrar la eficacia de la incorporación de las ...

  5. Medicina tradicional Maya-Yucateca: un estudio sobre esterilidad femenina

    OpenAIRE

    Azalia Pintado González

    2013-01-01

    En esta investigación se analiza la atención que se da a la esterilidad femenina, vista como un problema de salud pública, con la medicina tradicional en cuatro comunidades de la región Maya-Yucateca de Quintana Roo, en México. Durante ocho meses se realizó un estudio con 16 terapeutas tradicionales de esta zona, con quienes se estudió el proceso de atención (valoración, diagnóstico y tratamiento) de la esterilidad femenina, considerada, entre otras causas, como un problema de desequilibrio d...

  6. Antes de los Estudios Culturales. Robert Warshow y la experiencia

    OpenAIRE

    Antonio Lastra

    2008-01-01

    Este artículo estudia la influencia del concepto de experiencia que desarrolla Robert Warshow. Warshow ha supuesto el contrapunto americano a las teorías desarrolladas por Walter Benjamien en Europa. Si bien ambos insistieron en la pobreza de la experiencia, como resultado de la tecnificación de la sociedad, Warshow supo introducir matizaciones que influyeron en todo el círculo de intelectuales concentrados en Nueva York durante la etapa de consolidación de los Estudios Culturales. This paper...

  7. Estudio de bloques constructivos en algoritmos genéticos

    OpenAIRE

    Murias Rodríguez, Angel

    2007-01-01

    Estudio experimental sobre el efecto de las modificaciones en los bloques constructivos. Para conseguirlo, primero se ha diseñado un algoritmo genético genérico con posibilidad de adaptarlo a un problema específico (función de objetivo a optimizar) e incorporar fácilmente diferentes características que pueden tener estos algoritmos. Como referencia de comparación se ha diseñado y implementado un algoritmo genético estándar y los algoritmos con las modificaciones. Se han probado los algorit...

  8. Institucional: Centro de Estudios en Contabilidad Internacional (CECIN)

    OpenAIRE

    Revista Institucional de la Facultad de Ciencias Económicas

    2010-01-01

    Durante el mes de Julio de 2008 el Consejo Académico de la Facultad de Ciencias Económicas (UNLP) aprobó la creación del Centro de Estudios en Contabilidad Internacional (CECIN), dependiendo funcionalmente del Departamento de Contabilidad. El CECIN integra conocimientos teóricos de la disciplina contable con aplicaciones prácticas tendientes a dar respuestas a las necesidades que demanda la sociedad en diversos campos, especialmente a partir de los desarrollos internacionales en Contabilidad....

  9. Fracaso de bancos comerciales. Un estudio de eficiencia y productividad

    OpenAIRE

    González Bravo, M. Isabel; Mariaca Daza, René

    2010-01-01

    El estudio de la relación entre el comportamiento de la productividad de las entidades bancarias y su capacidad de continuar en el mercado, constituye el objetivo de la presente investigación. Será por medio del empleo de los Índices de Malmquist, mismos que se derivan de la técnica econométrica no paramétrica del Análisis de Datos Envolventes (DEA), que se obtendrán los resultados que permitirán concluir que no es posible establecer una relación directa entre la eficiencia, la productividad ...

  10. Proyecto final de estudios, una experiencia académica

    OpenAIRE

    Puglesi, Alfredo E.; Bernasconi, María Susana

    2011-01-01

    Inserto en la temática de las innovaciones, experiencias e investigación en las tecnologías aplicadas, este trabajo describe la realización del último Proyecto Final de Estudios (PFE) por parte de alumnos de la carrera de Ingeniería en Mecatrónica de la Facultad de Ingeniería de la Universidad Nacional de Cuyo y en el marco del convenio que la misma tiene con la de l'École Nationale d'Ingénieurs de Brest (Francia), mediante el cual, dos alumnos concurren anualmente para cursar los...

  11. Caracterización y potencial probiótico de bacterias lácticas aisladas de leche de oveja guirra

    OpenAIRE

    AMOROCHO CRUZ, CLAUDIA MILENA

    2011-01-01

    Diversos estudios señalan que varias especies pertenecientes a las Bacterias Acido Lácticas (BAL) poseen propiedades probióticas y se encuentran comúnmente en los derivados lácteos. Actualmente, en la Comunidad Valenciana se comercializan quesos frescos y madurados elaborados a partir de la leche de oveja guirra, autóctona de esta comunidad e incluida dentro del catálogo de razas protegidas en España. Sin embargo, hasta el momento no se han realizado ensayos para determinar el potencial probi...

  12. Estrategias de análisis de interacciones gen-ambiente en estudios GWAS

    OpenAIRE

    Alonso Aguado, Maria Henar

    2014-01-01

    Se realizaron estudios de asociación para encontrar los SNP de susceptibilidad para el riesgo de cáncer colorrectal y la interacción con el Índice de Masa Corporal (IMC). Este estudio de epidemiología genética está compuesto por 6 estudios de casos y controles por un total de 9929 individuos. Se evaluaron diversos modelos descritos para analizar interacciones gen-ambiente y métodos de meta-análisis para combinar los resultados de los 6 estudios.

  13. Estudio epidemiológico de salud oral en adultos. Comunidad Valenciana, 2006

    OpenAIRE

    Eustaquio Raga, María Vicenta

    2008-01-01

    RESUMEN En las últimas dos décadas se han venido realizando estudios epidemiológicos de salud oral en adultos en las diferentes comunidades autónomas españolas. Así la ausencia de dicho estudio de ámbito autonómico valenciano justifica plenamente su realización. En la realización del presente estudio nos hemos propuesto como objetivo general el evaluar el estado de salud bucodental de la población adulta y mayor de la Comunidad Valenciana. Se ha diseñado un estudio transversal o de p...

  14. Estudios de impacto ambiental en los proyectos de líneas eléctricas

    OpenAIRE

    López Roda, Lorena

    2009-01-01

    Mediante la elaboración del proyecto fin de carrera "Estudios de Impacto Ambiental en los proyectos de líneas eléctricas", se pretende revisar y conocer las metodologías de estudios de impacto ambiental asociadas a líneas eléctricas aéreas. Para conseguir el objetivo del proyecto será necesario: - Analizar la diversa normativa europea, nacional y de cada Comunidad Autónoma, existente y necesaria para los estudios de impacto ambiental. - Describir el procedimiento a seguir en un estudio de imp...

  15. Cómo medir la violencia audiovisual: principales métodos y estudios realizados

    OpenAIRE

    María Marcos Ramos

    2012-01-01

    El presente artículo, de carácter descriptivo, analiza los principales métodos científicos utilizados en las Ciencias Sociales para analizar la violencia audiovisual. Así, los experimentos de laboratorio, o investigación experimental., estudios de campo, estudios correlacionales, estudios de panel longitudinal, experimentos naturales, estudios de intervención y revisión de meta-análisis han sido los principales métodos empleados por los investigadores más destacados en el campo de las Cien...

  16. Bacteria Experiment May Point Way to Slow Zika's Spread

    Science.gov (United States)

    ... nlm.nih.gov/medlineplus/news/fullstory_158661.html Bacteria Experiment May Point Way to Slow Zika's Spread ... 2016 (HealthDay News) -- Experiments in mosquitoes suggest that bacteria may help curb the spread of the Zika ...

  17. Smoking Triggers Big Changes in Mouth Bacteria, Study Finds

    Science.gov (United States)

    ... 158024.html Smoking Triggers Big Changes in Mouth Bacteria, Study Finds But quitting eventually returns levels to ... research also found that the proper mix of bacteria in the mouth is restored if people quit ...

  18. Environmental pollution detection and bioremediation by marine bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; De, J.; Iyer, S.R.

    Microorganisms, in particular bacteria, play far more important ecological roles in natural environments than their small sizes would suggest. The environment for bacteria is everything that surrounds and sustains them including air, plant, animal...

  19. Antibiotic-Resistant Bacteria Detected in Sewage Spill

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_160031.html Antibiotic-Resistant Bacteria Detected in Sewage Spill 'People need to be ... News) -- Sewer line breaks can release antibiotic-resistant bacteria that pose a public health threat, a new ...

  20. Gut Bacteria May Hold Clues to Chronic Fatigue Syndrome

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_159905.html Gut Bacteria May Hold Clues to Chronic Fatigue Syndrome Intestinal ... doctors -- may be influenced by a person's intestinal bacteria -- sometimes called gut microbiome, new research finds. "Patients ...

  1. Molecular and chemical dialogues in bacteria-protozoa interactions

    NARCIS (Netherlands)

    Song, Chunxu; Mazzola, M.; Cheng, Xu; Oetjen, Janina; Alexandrov, Theodore; Dorrestein, Pieter C.; Watrous, Jeramie; van der Voort, Menno; Raaijmakers, Jos

    2015-01-01

    Protozoan predation of bacteria can significantly affect soil microbial community composition and ecosystem functioning. Bacteria possess diverse defense strategies to resist or evade protozoan predation. For soil-dwelling Pseudomonas species, several secondary metabolites were proposed to provide p

  2. Bacteria Experiment May Point Way to Slow Zika's Spread

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_158661.html Bacteria Experiment May Point Way to Slow Zika's Spread Infecting ... 4, 2016 WEDNESDAY, May 4, 2016 (HealthDay News) -- Experiments in mosquitoes suggest that bacteria may help curb ...

  3. Interactions between Paramyxoviruses and Bacteria: Implications for Pathogenesis and Intervention

    NARCIS (Netherlands)

    D.T. Nguyen (Tien)

    2014-01-01

    markdownabstract__Abstract__ Globally, respiratory tract diseases caused by bacteria and viruses are an important burden of disease. Respiratory bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus) can colonize the upper respiratory tract. The

  4. Frequency of Resistance and Susceptible Bacteria Isolated from Houseflies

    Directory of Open Access Journals (Sweden)

    B Davari

    2010-12-01

    Conclusion: Houseflies collected from hospitals and slaughterhouse may be involved in the spread of drug resistant bacteria and may increase the potential of human exposure to drug resistant bacteria.

  5. Oh What a Tangled Biofilm Web Bacteria Weave

    Science.gov (United States)

    ... Inside Life Science > Oh What a Tangled Biofilm Web Bacteria Weave Inside Life Science View All Articles | Inside Life Science Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May ...

  6. Un debate metodológico entre dos aproximaciones al estudio de caso: Caso de conciencia frente a estudio de caso histórico-humanista

    OpenAIRE

    Fernández Cano, Antonio; Lara Moreno, Teresa; de Dios Melgarejo Jaldo, Juan; Bueno Sánchez, Angel

    2002-01-01

    Not available

    Este estudio considera dos aproximaciones a un método de investigación tan complejo como el estudio de caso. Por un lado, el antiguo y seminal enfoque del caso de conciencia, se considera con profundidad. Por otro, también desarrolla conceptual y metodológicamente una de las diversas acepciones actuales al estudio de caso, la histórico-humanista según propuso Caro Baroja. El objetivo central de este trabajo podría ser presentar la aproximación histórico-humani...

  7. Phylogenetic analysis and development of probes for differentiating methylotrophic bacteria.

    OpenAIRE

    Brusseau, G A; Bulygina, E S; Hanson, R S

    1994-01-01

    Fifteen small-subunit rRNAs from methylotrophic bacteria have been sequenced. Comparisons of these sequences with 22 previously published sequences further defined the phylogenetic relationships among these bacteria and illustrated the agreement between phylogeny and physiological characteristics of the bacteria. Phylogenetic trees were constructed with 16S rRNA sequences from methylotrophic bacteria and representative organisms from subdivisions within the class Proteobacteria on the basis o...

  8. ANTIMICROBIAL ACTIVITY OF MEDICINAL PLANTS AGAINST DIFFERENT STRAINS OF BACTERIA

    OpenAIRE

    Alexander Vatľák; Adriana Kolesárová; Nenad Vukovič; Katarína Rovná; Jana Petrová; Viktória Vimmerová; Lukáš Hleba; Martin Mellen; Miroslava Kačániová

    2014-01-01

    In this study, methanolic extracts of Tilia cordata Mill. and Aesculus hippocastanum which had been described in herbal books, were screened for their antimicrobial activity against gramnegative and grampositive bacteria. The following strains of bacteria for antimicrobial activity were used gramnegative bacteria: Escherichia coli CCM 3988, Listeria ivanovii CCM 5884, Listeria innocua CCM 4030, Pseudomonas aeruginosa CCM 1960, Serratia rubidaea CCM 4684 and grampositive bacteria: Brochothrix ...

  9. New Insight on the Response of Bacteria to Fluoride

    OpenAIRE

    Breaker, R R

    2012-01-01

    Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biolog...

  10. Control of Fusarium Wilt of Chili With Chitinolytic Bacteria

    OpenAIRE

    DWI SURYANTO; SITI PATONAH; ERMAN MUNIR

    2010-01-01

    Biological control of plant disease using antagonistic microorganism has been obtaining much attention and implemented for decades. One of the potential microorganisms used in this strategy is chitinolytic bacteria. Utilization of this bacteria ranges from cell life, enzymes, genes, or other metabolites. In this study, we examined the ability of chitinolytic bacteria as a biocontrol agent of Fusarium wilt of red chili (Capsicum annuum L.) seedlings. The ability of chitinolytic bacteria to sup...

  11. Probiotic bacteria in prevention and treatment of diarrhea

    OpenAIRE

    Jasmina Havranek; Šimun Zamberlin; Iva Dolenčić Špehar; Tamara Prtilo; Milna Tudor; Dubravka Samaržija

    2009-01-01

    Probiotic bacteria have beneficial effects in prevention and treatment of different diseases. The results of preventive and therapeutic effect of probiotic bacteria on diarrhea during last ten years are shown in this paper. The greatest preventive and therapeutic effect of probiotic bacteria was identified for acute diarrhea in children caused by rotaviruses. Significant, but slightly lower effect of probiotic bacteria was proved for antibiotic associated diarrhea. Positive effect in preventi...

  12. [RAPD analysis of plant pathogenic coryneform bacteria].

    Science.gov (United States)

    Yin, Yan-Ni; Chen, Yong-Fang; Li, Shi-Mo; Guo, Jian-Hua

    2005-12-01

    RAPD analysis was used for the taxonomy of plant pathogenic coryneform bacteria, especially for the classification of two new pathogens (Curtobacterium flaccumfaciens pv. basellae pv. nov. and Curtobacterium flaccumfaciens pv. beticola pv. nov.). 20 random primers were screened from 50 ones to detect polymorphism among the total strains used. 80.4% were polymorphic bands among the 225 ones produced. The results of pairwise similarity and UPGMA cluster analysis suggest that the two new pathovars of sugar beet (Beta vulgaris var. saccharifera) and malabar spinach (Basella rubra) are genetically close related with Curtobacterium flacumfaciens, and the minimal similarity coefficient is 0.6511. According to the RAPD analysis and previous research, some newly made taxonomic changes of the plant pathogenic coryneform bacteria are discussed. PMID:16496687

  13. Ancient bacteria show evidence of DNA repair

    DEFF Research Database (Denmark)

    Johnson, Sarah Stewart; Hebsgaard, Martin B; Christensen, Torben R;

    2007-01-01

    geological timescales. There has been no direct evidence in ancient microbes for the most likely mechanism, active DNA repair, or for the metabolic activity necessary to sustain it. In this paper, we couple PCR and enzymatic treatment of DNA with direct respiration measurements to investigate long...... this long-term survival is closely tied to cellular metabolic activity and DNA repair that over time proves to be superior to dormancy as a mechanism in sustaining bacteria viability.......-term survival of bacteria sealed in frozen conditions for up to one million years. Our results show evidence of bacterial survival in samples up to half a million years in age, making this the oldest independently authenticated DNA to date obtained from viable cells. Additionally, we find strong evidence that...

  14. Resistant bacteria in stem cell transplant recipients

    Directory of Open Access Journals (Sweden)

    Nucci Marcio

    2002-01-01

    Full Text Available Bacterial infections account for most infections in hematopoietic stem cell transplant recipients. While early mortality reduced dramatically with the introduction of the concept of empirical antibiotic therapy in neutropenic patients, no effect of prophylaxis on the mortality was observed in many studies. On the other hand, antibiotic prophylaxis has resulted in the emergence of resistance among bacteria. In addition, the choice of the antibiotic regimen for empirical therapy and the practices of antibiotic therapy during neutropenia may result in a significant shift in the pattern of bacterial infections. The use of quinolones and vancomycin as prophylaxis, and of carbapenems and vancomycin in the empirical antibiotic therapy, are associated with the appearance of resistant Gram-positive and Gram-negative bacteria. Therefore, hematologists must be aware of the impact of these practices on the emergence of infections due to multi-resistant pathogens, since these infections may be associated with increased mortality.

  15. Horizontal gene transfer between bacteria and animals.

    Science.gov (United States)

    Dunning Hotopp, Julie C

    2011-04-01

    Horizontal gene transfer is increasingly described between bacteria and animals. Such transfers that are vertically inherited have the potential to influence the evolution of animals. One classic example is the transfer of DNA from mitochondria and chloroplasts to the nucleus after the acquisition of these organelles by eukaryotes. Even today, many of the described instances of bacteria-to-animal transfer occur as part of intimate relationships such as those of endosymbionts and their invertebrate hosts, particularly insects and nematodes, while numerous transfers are also found in asexual animals. Both of these observations are consistent with modern evolutionary theory, in particular the serial endosymbiotic theory and Muller's ratchet. Although it is tempting to suggest that these particular lifestyles promote horizontal gene transfer, it is difficult to ascertain given the nonrandom sampling of animal genome sequencing projects and the lack of a systematic analysis of animal genomes for such transfers. PMID:21334091

  16. Quorum sensing in plant-pathogenic bacteria.

    Science.gov (United States)

    Von Bodman, Susanne B; Bauer, W Dietz; Coplin, David L

    2003-01-01

    Quorum sensing (QS) allows bacteria to assess their local population density and/or physical confinement via the secretion and detection of small, diffusible signal molecules. This review describes how phytopathogenic bacteria have incorporated QS mechanisms into complex regulatory cascades that control genes for pathogenicity and colonization of host surfaces. Traits regulated by QS include the production of extracellular polysaccharides, degradative enzymes, antibiotics, siderophores, and pigments, as well as Hrp protein secretion, Ti plasmid transfer, motility, biofilm formation, and epiphytic fitness. Since QS regulatory systems are often required for pathogenesis, interference with QS signaling may offer a means of controlling bacterial diseases of plants. Several bacterial pathogens of plants that have been intensively studied and have revealed information of both fundamental and practical importance are reviewed here: Agrobacterium tumefaciens, Pantoea stewartii, Erwinia carotovora, Ralstonia solanacearum, Pseudomonas syringae, Pseudomonas aeruginosa, and Xanthomonas campestris. PMID:12730390

  17. Bacteria, some permanent tenants Space Station

    International Nuclear Information System (INIS)

    Vacuum cleaners to operate the vacuum or rags with ethanol they are the products of cleaning of the astronauts. Is there tight spaces fully sterilized? It seems not, even in the Space Station International (ISS). When it comes to bacteria, they are able to travel more than 400 kilometers housed in costumes, bodies and interior of the astronauts themselves and settle in a enclosed space where-unlike in a cleanroom 'terrestre- the air is not recycled. A NASA study has found an abundance of bacteria 'opportunists' which, although harmless on Earth, they might derivasen cause infections in inflammations or skin irritations. Not forgetting those fungi that could damage or affect the infrastructure equipment space. (Author)

  18. The Chemical Ecology of Predatory Soil Bacteria.

    Science.gov (United States)

    Findlay, Brandon L

    2016-06-17

    The study of natural products is entering a renaissance, driven by the discovery that the majority of bacterial secondary metabolites are not produced under standard laboratory conditions. Understanding the ecological role of natural products is key to efficiently directing our screening efforts, and to ensuring that each screen efficiently captures the full biosynthetic repertoire of the producing organisms. Myxobacteria represent one of the most common and diverse groups of bacteria, with roughly 2500 strains publically available. Fed largely through predation, the myxobacteria have developed a large repertoire of natural products that target other microorganisms, including bacteria and fungi. Many of these interactions can be observed in predation assays, providing direct evidence for environmental interactions. With a focus on Myxococcus xanthus, this review will highlight how recent advances in myxobacteria are revealing the chemical ecology of bacterial natural products. PMID:27035738

  19. Emerging roles of RNA modifications in bacteria.

    Science.gov (United States)

    Marbaniang, Carmelita Nora; Vogel, Jörg

    2016-04-01

    RNA modifications are known to abound in stable tRNA and rRNA, where they cluster around functionally important regions. However, RNA-seq based techniques profiling entire transcriptomes are now uncovering an abundance of modified ribonucleotides in mRNAs and noncoding RNAs, too. While most of the recent progress in understanding the regulatory influence of these new RNA modifications stems from eukaryotes, there is growing evidence in bacteria for modified nucleotides beyond the stable RNA species, including modifications of small regulatory RNAs. Given their small genome size, good genetic tractability, and ample knowledge of modification enzymes, bacteria offer excellent model systems to decipher cellular functions of RNA modifications in many diverse physiological contexts. This review highlights how new global approaches combining classic analysis with new sequencing techniques may usher in an era of bacterial epitranscriptomics. PMID:26803287

  20. Sulfur-oxidizing bacteria in environmental technology.

    Science.gov (United States)

    Pokorna, Dana; Zabranska, Jana

    2015-11-01

    Hydrogen sulfide is widely known as the most undesirable component of biogas that caused not only serious sensoric and toxic problems, but also corrosion of concrete and steel structures. Many agricultural and industrial waste used in biogas production, may contain a large amount of substances that serve as direct precursors to the formation of sulfide sulfur-sources of hydrogen sulfide in the biogas. Biological desulfurization methods are currently promoted to abiotic methods because they are less expensive and do not produce undesirable materials which must be disposed of. The final products of oxidation of sulfides are no longer hazardous. Biological removal of sulfide from a liquid or gaseous phase is based on the activity of sulfur-oxidizing bacteria. They need an oxidizing agent such as an acceptor of electrons released during the oxidation of sulfides-atmospheric oxygen or oxidized forms of nitrogen. Different genera of sulfur-oxidizing bacteria and their technological application are discussed. PMID:25701621

  1. ESTUDIO DEL EFECTO QUIMIOTÁCTICO DE LOS EXUDADOS RADICALES DEL ARROZ SOBRE Azospirillum brasilense Sp7 Y A. brasilense R5(15). PRODUCCIÓN DE AUXINAS POR AMBAS CEPAS

    OpenAIRE

    Mabel Pazos; Digna Hernández; Annia Hernández

    2003-01-01

    El género Azospirillum agrupa bacterias diazotróficas de vida libre, ampliamente encontradas en suelos tropicales y subtropicales, en asociación con raíces de cultivos de importancia económica como arroz, trigo y diversas especies vegetales. La gran mayoría de los estudios realizados con este género han demostrado su distribución prácticamente universal y sus numerosos efectos sobre el crecimiento de las plantas que coloniza. En este trabajo se demuestra el efecto quimiotáctico que ejercen lo...

  2. Estudio de las poblaciones bacterianas y su relación con los parámetros físico químicos del tratamiento de Aguas residuales

    OpenAIRE

    Reyes Sosa, Mariela Beatriz

    2014-01-01

    Uno de los procesos más utilizados en el tratamiento de aguas residuales es el de fangos activados en sus distintas modalidades. La compleja comunidad de microorganismos que participan en los procesos de fangos activos es su principal característica para llevar a cabo con éxito la depuración del agua. A pesar de los muchos estudios realizados para conocer la comunidad de bacterias que integran el proceso de fangos activos falta mucho por conocer de la estructura y dinámica...

  3. Campylobacter spp. en grangas y matadero de broilers y en perros domésticos en Andalucía: estudio microbiológico, epidemiológico y de sensibilidad antimicrobiana

    OpenAIRE

    Torralbo Montoro, Alicia

    2013-01-01

    La campilobacteriosis es una enfermedad infecciosa producida por bacterias del género Campylobacter, que supone en la actualidad la zoonosis más importante a nivel mundial. En contraste, en los animales, Campylobacter puede estar presente como comensal en el tracto digestivo sin causar enfermedad clínica. Se ha realizado un estudio microbiológico y epidemiológico de la infección de las distintas especies del género Campylobacter en broilers de Andalucía desde el año 2010 hasta ...

  4. METODOLOGÍA PARA UN ESTUDIO DIALECTAL URBANO: EL CASO DEL ESTUDIO DEL ESPAÑOL DE BUCARAMANGA

    OpenAIRE

    Luz Mary Rincón

    2007-01-01

    Una constante preocupación de los estudiosos de la lengua es el desarrollo de técnicas confiables en la investigación del habla en contextos urbanos con el fin de ofrecer una teoría de la lengua como se observa en su uso social. Para esto hay que tener en cuenta el aporte de la sociolingüística en el estudio de la lengua en su contexto social y toda aquella gama de contribuciones que se han alejado de las tradicionales técnicas usadas en dialectología. En el presente artículo se da cuenta de ...

  5. Hydrocarbonoclastic bacteria: from bioremediation to bioenergy feedstock

    OpenAIRE

    Carvalho, Ana Rita Castro

    2015-01-01

    Tese de Doutoramento em Engenharia Química e Biológica. Bacterial storage lipids are being considered as viable alternative feedstocks for industrial and biotechnological applications, compared to conventional ones. The production of these bacterial compounds can be obtained from different carbon sources, including inexpensive and recalcitrant wastes. This thesis explores the potential of using hydrocarbonoclastic bacteria to obtain lipid reserve substances from hydrocarbon-based wastes, p...

  6. Food preservation using antifungal lactic acid bacteria

    OpenAIRE

    Crowley, Sarah Catherine Mary

    2013-01-01

    Fungal spoilage of food and feed prevails as a major problem for the food industry. The use antifungal-producing lactic acid bacteria (LAB) may represent a safer, natural alternative to the use of chemical preservatives in foods. A large scale screen was undertaken to identify a variety of LAB with antifungal properties from plant, animal and human sources. A total of 6,720 LAB colonies were isolated and screened for antifungal activity against the indicator Penicillium expansum. 94 broad-spe...

  7. RNA-Seq for Plant Pathogenic Bacteria

    OpenAIRE

    Kimbrel, Jeffrey A.; Yanming Di; Cumbie, Jason S.; Chang, Jeff H.

    2011-01-01

    The throughput and single-base resolution of RNA-Sequencing (RNA-Seq) have contributed to a dramatic change in transcriptomic-based inquiries and resulted in many new insights into the complexities of bacterial transcriptomes. RNA-Seq could contribute to similar advances in our understanding of plant pathogenic bacteria but it is still a technology under development with limitations and unknowns that need to be considered. Here, we review some new developments for RNA-Seq and highlight recent...

  8. Plague Bacteria Target Immune Cells During Infection

    OpenAIRE

    Marketon, Melanie M.; DePaolo, R. William; DeBord, Kristin L.; Jabri, Bana; Schneewind, Olaf

    2005-01-01

    The plague is caused by the bacterium Yersinia pestis. Plague bacteria are thought to inject effector Yop proteins into host cells via the type III pathway. The identity of the host cells targeted for injection during plague infection is unknown. We found, using Yop β-lactamase hybrids and fluorescent staining of live cells from plague-infected animals, that Y. pestis selected immune cells for injection. In vivo, dendritic cells, macrophages, and neutrophils were injected most frequently, whe...

  9. Study of fatty acid-bacteria interactions

    International Nuclear Information System (INIS)

    Complete text of publication follows. During our work we investigated fatty acid-bacteria interactions. The antibacterial property of fatty acids was reported by several authors. Despite of them there is not reassuring explanation about the mechanism of the antibacterial activity of these compounds. An effect can considerably change in case of different structured fatty acids. Our earlier studies conduct that small changes in the structures can modify changes in their behavior towards bacteria. The stearic acid does not cause any antibacterial effects during the first few hours of the investigation, may even help the bacterial growth. However, linolic acid (C18:2) shows a strong antibacterial effect during the first hours. After 24 hours this effect wears out and the bacteria have adapted to the stress. We studied the antibacterial activity using direct bioautography. This method has the advantage to allow examining lipophilic compounds. The linoleic acid decomposes in time under different physiological conditions creating numerous oxidized molecules. This may be the reason of its antimicrobial effect. For studying this phenomenon we used infrared and mass spectroscopic methods. We applied infrared spectroscopy for indicating any changes in the spectra of the fatty acids after the interaction of fatty acids with bacteria. So we are able to deduct on what could happen during these process. We paid great attention towards the changes of double bonds, on methylation and demethylation processes. Using mass spectroscopy we searched for oxidized products that may play important role in this process. These studies are only part of our more widespreading investigations, dealing with the antimicrobial properties of fatty acids.

  10. Bacterial biofilms. Bacteria Quorum sensing in biofilms

    OpenAIRE

    E. S. Vorobey; O. S. Voronkova; A. I. Vinnikov

    2012-01-01

    Data on biofilms, their structure and properties, peculiarities of formation and interaction between microorganisms in the film are presented. Information on discovery and study of biofilms, importance of biofilms in the medical and clinical microbiology are offered. The data allow to interpret biofilm as a form of existence of human normal microflora. For the exchange of information within the biofilm between the individual cells of the same or different species bacteria use the signal molec...

  11. Separation and Purification of Bacteria from Soil

    OpenAIRE

    Bakken, Lars R.

    1985-01-01

    Bacteria were released and separated from soil by a simple blending-centrifugation procedure. The percent yield of bacterial cells (microscopic counts) in the supernatants varied over a wide range depending on the soil type. The superantants contained large amounts of noncellular organic material and clay particles. Further purification of the bacterial cells was obtained by centrifugation in density gradients, whereby the clay particles and part of the organic materials sedimented. A large p...

  12. Revolutionizing membrane protein overexpression in bacteria

    OpenAIRE

    Schlegel, Susan; Klepsch, Mirjam; Gialama, Dimitra; Wickström, David; Slotboom, Dirk Jan; De Gier, Jan‐Willem

    2010-01-01

    Summary The bacterium Escherichia coli is the most widely used expression host for overexpression trials of membrane proteins. Usually, different strains, culture conditions and expression regimes are screened for to identify the optimal overexpression strategy. However, yields are often not satisfactory, especially for eukaryotic membrane proteins. This has initiated a revolution of membrane protein overexpression in bacteria. Recent studies have shown that it is feasible to (i) engineer or ...

  13. Metabolic Flexibility of Sulfate-Reducing Bacteria

    OpenAIRE

    Plugge, Caroline M.; Zhang, Weiwen; Scholten, Johannes C. M.; Stams, Alfons J. M.

    2011-01-01

    Dissimilatory sulfate-reducing prokaryotes (SRB) are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As a consequence, SRB would be expected in the sulfate-containing upper sediment layers, whereas me...

  14. Electromagnetic low-frequency fields and bacteria

    Czech Academy of Sciences Publication Activity Database

    Foltýn, D.; Čermáková, E.; Kolářová, M.; Bartušek, Karel

    Košice : RVS VLA Košice, 2002 - (Džunda, M.; Brůnová, B.), s. 133 - 137 ISBN 80-7166-034-5. [New trends of development in aviation. Košice (SK), 01.09.2002] Institutional research plan: CEZ:AV0Z2065902 Keywords : low-frequency fields * bacteria Staphylococcus aureus * low-frequency ELM fields Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  15. Biology of Moderately Halophilic Aerobic Bacteria

    OpenAIRE

    Nieto Gutiérrez, Joaquín José; Ventosa Ucero, Antonio; Oren, Aharon

    1998-01-01

    The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms...

  16. Bioactive Compounds from Marine Bacteria and Fungi

    OpenAIRE

    Debbab, Abdessamad; Aly, Amal H.; Lin, Wen H.; Proksch, Peter

    2010-01-01

    Summary Marine bacteria and fungi are of considerable importance as new promising sources of a huge number of biologically active products. Some of these marine species live in a stressful habitat, under cold, lightless and high pressure conditions. Surprisingly, a large number of species with high diversity survive under such conditions and produce fascinating and structurally complex natural products. Up till now, only a small number of microorganisms have been investigated for bioactive me...

  17. Ferric Iron Reduction by Acidophilic Heterotrophic Bacteria

    OpenAIRE

    Johnson, D. Barrie; McGinness, Stephen

    1991-01-01

    Fifty mesophilic and five moderately thermophilic strains of acidophilic heterotrophic bacteria were tested for the ability to reduce ferric iron in liquid and solid media under aerobic conditions; about 40% of the mesophiles (but none of the moderate thermophiles) displayed at least some capacity to reduce iron. Both rates and extents of ferric iron reduction were highly strain dependent. No acidophilic heterotroph reduced nitrate or sulfate, and (limited) reduction of manganese(IV) was note...

  18. Tumour targeting with systemically administered bacteria.

    LENUS (Irish Health Repository)

    Morrissey, David

    2012-01-31

    Challenges for oncology practitioners and researchers include specific treatment and detection of tumours. The ideal anti-cancer therapy would selectively eradicate tumour cells, whilst minimising side effects to normal tissue. Bacteria have emerged as biological gene vectors with natural tumour specificity, capable of homing to tumours and replicating locally to high levels when systemically administered. This property enables targeting of both the primary tumour and secondary metastases. In the case of invasive pathogenic species, this targeting strategy can be used to deliver genes intracellularly for tumour cell expression, while non-invasive species transformed with plasmids suitable for bacterial expression of heterologous genes can secrete therapeutic proteins locally within the tumour environment (cell therapy approach). Many bacterial genera have been demonstrated to localise to and replicate to high levels within tumour tissue when intravenously (IV) administered in rodent models and reporter gene tagging of bacteria has permitted real-time visualisation of this phenomenon. Live imaging of tumour colonising bacteria also presents diagnostic potential for this approach. The nature of tumour selective bacterial colonisation appears to be tumour origin- and bacterial species- independent. While originally a correlation was drawn between anaerobic bacterial colonisation and the hypoxic nature of solid tumours, it is recently becoming apparent that other elements of the unique microenvironment within solid tumours, including aberrant neovasculature and local immune suppression, may be responsible. Here, we consider the pre-clinical data supporting the use of bacteria as a tumour-targeting tool, recent advances in the area, and future work required to develop it into a beneficial clinical tool.

  19. Quorum Sensing in Gram-Negative Bacteria

    OpenAIRE

    BOŞGELMEZ-TINAZ, Gülgün

    2003-01-01

    It has become increasingly and widely recognised that bacteria do not live as isolated entities but instead exist as communities that exploit elaborate systems of intercellular communication to facilitate their adaptation to changing environmental conditions. A well-characterised example of such intercellular communication is quorum sensing. Quorum sensing depends on the production of diffusible signal molecules termed autoinducers or pheromones, which enable a bacterium to monitor its own ce...

  20. Bacteria Foraging Algorithm in Antenna Design

    OpenAIRE

    Biswa Binayak Mangaraj; Manas Ranjan Jena; Saumendra Kumar Mohanty

    2016-01-01

    A simple design procedure to realize an optimum antenna using bacteria foraging algorithm (BFA) is proposed in this paper. The first antenna considered is imaginary. This antenna is optimized using the BFA along with a suitable fitness function formulated by considering some performance parameters and their best values. To justify the optimum design approach, one 12-element Yagi-Uda antenna is considered for an experiment. The optimized result of this antenna obtained using the optimization a...

  1. Evolution of transcriptional regulatory circuits in bacteria

    OpenAIRE

    Perez, J. Christian; Groisman, Eduardo A.

    2009-01-01

    Related organisms typically respond to a given cue by altering the level or activity of orthologous transcription factors, which, paradoxically, often regulate expression of distinct gene sets. Although promoter rewiring of shared genes is primarily responsible for regulatory differences among related eukaryotic species, in bacteria, species-specific genes are often controlled by ancestral transcription factors and regulatory circuit evolution has been further shaped by horizontal gene transf...

  2. Mutation, Selection and Genetic Interactions in Bacteria

    OpenAIRE

    Gordo, I.; Sousa, A.

    2010-01-01

    Mutation is the ultimate source of genetic variation. The rate at whichnew mutations typically occurs, their effects on fitness and the strength and type of genetic interactions between different mutations are key for understanding the evolution of any population. Estimates of these parameters in organisms such as bacteria will have a profound impact on our understanding of their biology, diversity, rate of speciation and in our health. Experimental evolution with bact...

  3. Experimental evolution with bacteria in complex environments

    OpenAIRE

    Hall, Alex R.

    2009-01-01

    Experiments with microbes are a powerful tool for addressing general questions in evolutionary ecology. Microbial evolution is also interesting in its own right, and often clinically relevant. I have used experimental evolution of bacteria (Pseudomonas spp.) in controlled laboratory environments to investigate the role of environmental heterogeneity in the evolution of phenotypic diversity. Some of my results provide insight on general processes, while others are specific to ba...

  4. Cold atmospheric plasma decontamination against nosocomial bacteria

    OpenAIRE

    Klämpfl , Tobias Gabriel

    2014-01-01

    Nosocomial pathogens are a considerable public threat. In order to limit their spread, cold atmospheric plasma (CAP) was investigated as new alternative to common decontamination strategies. During my work I developed a Surface micro-discharge (SMD) electrode system, characterized the CAP generated at ambient air conditions, studied its decontaminating behavior against nosocomial bacteria such as Clostridium difficile endospores and revealed factors influencing the decontamination. All in all...

  5. [Phylogenetic analysis of bacteria of extreme ecosystems].

    Science.gov (United States)

    Romanovskaia, V A; Parfenova, V V; Bel'kova, N L; Sukhanova, E V; Gladka, G V; Tashireva, A A

    2014-01-01

    Phylogenetic analysis of aerobic chemoorganotrophic bacteria of the two extreme regions (Dead Sea and West Antarctic) was performed on the basis of the nucleotide sequences of the 16S rRNA gene. Thermotolerant and halotolerant spore-forming bacteria 7t1 and 7t3 of terrestrial ecosystems Dead Sea identified as Bacillus licheniformis and B. subtilis subsp. subtilis, respectively. Taking into account remote location of thermotolerant strain 6t1 from closely related strains in the cluster Staphylococcus, 6t1 strain can be regarded as Staphylococcus sp. In terrestrial ecosystems, Galindez Island (Antarctic) detected taxonomically diverse psychrotolerant bacteria. From ornithogenic soil were isolated Micrococcus luteus O-1 and Microbacterium trichothecenolyticum O-3. Strains 4r5, 5r5 and 40r5, isolated from grass and lichens, can be referred to the genus Frondihabitans. These strains are taxonomically and ecologically isolated and on the tree diagram form the joint cluster with three isolates Frondihabitans sp., isolated from the lichen Austrian Alps, and psychrotolerant associated with plants F. cladoniiphilus CafT13(T). Isolates from black lichen in the different stationary observation points on the south side of a vertical cliff identified as: Rhodococcus fascians 181n3, Sporosarcina aquimarina O-7, Staphylococcus sp. 0-10. From orange biofilm of fouling on top of the vertical cliff isolated Arthrobacter sp. 28r5g1, from the moss-- Serratia sp. 6r1g. According to the results, Frondihabitans strains most frequently encountered among chemoorganotrophic aerobic bacteria in the Antarctic phytocenoses. PMID:25007437

  6. Cellulose biosynthesis and function in bacteria.

    OpenAIRE

    Ross, P; Mayer, R; Benziman, M

    1991-01-01

    The current model of cellulose biogenesis in plants, as well as bacteria, holds that the membranous cellulose synthase complex polymerizes glucose moieties from UDP-Glc into beta-1,4-glucan chains which give rise to rigid crystalline fibrils upon extrusion at the outer surface of the cell. The distinct arrangement and degree of association of the polymerizing enzyme units presumably govern extracellular chain assembly in addition to the pattern and width of cellulose fibril deposition. Most e...

  7. ESTUDIO CINEANTROPOMÉTRICO DEL JUGADOR DE TENIS ADOLESCENTE

    Directory of Open Access Journals (Sweden)

    Gema Torres Luque

    2006-01-01

    Full Text Available El propósito de este estudio fue aproximarse al perfil cineantropométrico de jugadores de tenis de edad adolescente. Para ello se seleccionaron 75 jugadores de tenis (47 varones y 26 mujeres a los cuales se les determinó el perfil antropométrico, composición corporal y somatotipo, mostrando a su vez las diferencias en cuanto al género. Todas las valoraciones se realizaron siguiendo las recomendaciones del Grupo Español de Cineantropometría, los tenistas fueron evaluados a la misma hora del día. Los resultados muestran diferencias significativamente mayores en los tenistas en peso, talla, perímetros bioestiloide y bicondíleo húmero, así como en diámetros en brazo contraído y perímetro del muslo y pierna. A su vez, las tenistas muestran un mayor porcentaje de grasa corporal y un menor porcentaje de masa ósea, no existiendo diferencias significativas respecto al porcentaje de masa muscular. El somatotipo marca una tendencia ecto mesomórfica para el género masculino, y una tendencia meso endomórfica para el género femenino. El estudio cineantropométrico del tenista adolescente permitirá una aproximación de referencia al perfil funcional del tenista y contribuir al máximo rendimiento deportivo.

  8. Estudio del climaterio en una muestra de mujeres uruguayas

    Directory of Open Access Journals (Sweden)

    Egaña, Ana

    2003-01-01

    Full Text Available Durante el climaterio la mujer experimenta una serie de cambios fisiológicos, que causan frecuentemente tanto patologías físicas como manifestaciones psicosomáticas, conocidas como “síndrome climatérico”. Nuestro país posee escasos antecedentes de estudios sobre este tema, a pesar de la importancia que dicha fase de vida tiene para la población femenina. Para este estudio se analizan los datos obtenidos a partir de fichas médicas y de encuestas aplicadas a una muestra de 200 mujeres entre 40 y 65 años de edad, residentes en Montevideo y otras poblaciones del interior del país. Se observa la influencia de diferentes variables que inciden en los síntomas que se presentan durante el período climatérico: el historial reproductivo, hábitos de vida y nutrición, así como también indicadores socioeconómicos.

  9. El experimento formativo en el estudio del lenguaje egocentrico

    Directory of Open Access Journals (Sweden)

    Rosalía Montealegre

    1998-01-01

    Full Text Available Este escrito analiza dos métodos experimentales: el genético-modelador y el estadístico (método de evaluación cuantitativa en el estudio de lenguaje egocéntrico como regulador y planificador de la acción en el niño. Se presentan unas retlexiones teóricas sobre los métodos y su empleo en la investigación realizada por la autora en la Universidad Estatal de Moscú sobre «El papel del lenguaje en la solución de tareas espaciales por niños de edad preescolar». A diferencia de la evaluación cuantitativa de los procesos psíquicos, el método genético-modelador apunta el estudio de formación de esos procesos. Este específico método genético, denominado también método del experimento formativo, es trabajado por los representantes de la Escuela de Vygotski.

  10. The growth of bacteria on organic compounds in drinking water

    NARCIS (Netherlands)

    Kooy, van der D.

    1984-01-01

    Growth ("regrowth") of bacteria In drinking water distribution systems results in a deterioration of the water quality. Regrowth of chemoheterotrophic bacteria depends on the presence of organic. compounds that serve as a nutrient source for these bacteria. A batch-culture technique was developed to

  11. Calculations of magnetic susceptibility of magnetoactic bacteria culture

    Czech Academy of Sciences Publication Activity Database

    Zablotskyy, Vitaliy A.; Yurchenko, Vitaliy; Kamysa, Y.; Chelombetskaya, M.

    2001-01-01

    Roč. 234, - (2001), s. 575-583. ISSN 0304-8853 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetotactic bacteria * magnetic susceptibility of magnetotactic bacteria * magnetic moment of magnetotactic bacteria Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.329, year: 2001

  12. Quantification and Qualification of Bacteria Trapped in Chewed Gum

    NARCIS (Netherlands)

    Wessel, Stefan W.; van der Mei, Henny C.; Morando, David; Slomp, Anje M.; van de Belt-Gritter, Betsy; Maitra, Amarnath; Busscher, Henk J.

    2015-01-01

    Chewing of gum contributes to the maintenance of oral health. Many oral diseases, including caries and periodontal disease, are caused by bacteria. However, it is unknown whether chewing of gum can remove bacteria from the oral cavity. Here, we hypothesize that chewing of gum can trap bacteria and r

  13. TMDLs (Total Maximum Daily Loads) for Bacteria Impairments

    OpenAIRE

    Benham, Brian Leslie, 1960-; Zeckoski, Sara C.

    2009-01-01

    When the concentration of bacteria exceeds the state-specified water-quality criteria, the water is deemed to have a bacteria or pathogen impairment. This publication explains how bacteria impairments are determined and how this relates to the TMDL process.

  14. Metabolism in bacteria at low temperature: A recent report

    Indian Academy of Sciences (India)

    Dipanwita Sengupta; Madhab K Chattopadhyay

    2013-06-01

    The adaptability of bacteria to extreme cold environments has been demonstrated from time to time by various investigators. Metabolic activity of bacteria at subzero temperatures is also evidenced. Recent studies indicate that bacteria continue both catabolic and anabolic activities at subzero temperatures. Implications of these findings are discussed.

  15. IDENTIFICATION OF INDUSTRIALLY IMPORTANT LACTIC ACID BACTERIA IN FOODSTUFFS

    OpenAIRE

    Prosekov, A.; Babich, O.; Bespomestnykh, K.

    2013-01-01

    Universal genus-specific primers for comparative analysis of two aligned 16S rRNA gene nucleotide sequences of lactic acid bacteria were constructed. The method to identify lactic acid bacteria and a comprehensive plan for their genus and species identification may be used to characterize isolated strains of the Lactobacillus genus bacteria and in quality control of foodstuffs enriched with Lactobacillus.

  16. Bacteria as transporters of phosphorus through soil

    DEFF Research Database (Denmark)

    Glæsner, N.; Bælum, Jacob; Jacobsen, C. S.;

    2016-01-01

    The transport of phosphorus (P) from agricultural land has led to the eutrophication of surface waters worldwide, especially in areas with intensive animal production. In this research, we investigated the role of bacteria in the leaching of P through three agricultural soils with different......RNA genes cell−1. Leaching of bacteria was in the range of 2.5–4.5 × 105 cells ml−1 prior to application of slurry to the three soil textures. After slurry application, leaching increased to 1.1 × 106 cells ml−1 in the loamy sand, 4.9 × 106 cells ml−1 in the sandy loam and 5.0 × 106 cells ml−1 in the loam....... Based on the reported P content of soil bacteria, 0.3–1.8% of the total P leached was present in the bacterial biomass when no slurry was applied, whereas slurry application increased the leaching of P from the bacterial biomass to 3−7.9% of total P leached. Bacterial leaching was related to the...

  17. Diversity and ecology of oxalotrophic bacteria.

    Science.gov (United States)

    Hervé, Vincent; Junier, Thomas; Bindschedler, Saskia; Verrecchia, Eric; Junier, Pilar

    2016-02-01

    Oxalate is present in environments as diverse as soils or gastrointestinal tracts. This organic acid can be found as free acid or forming metal salts (e.g. calcium, magnesium). Oxalotrophy, the ability to use oxalate as carbon and energy sources, is mainly the result of bacterial catabolism, which can be either aerobic or anaerobic. Although some oxalotrophic bacterial strains are commonly used as probiotics, little is known about the diversity and ecology of this functional group. This review aims at exploring the taxonomic distribution and the phylogenetic diversity of oxalotrophic bacteria across biomes. In silico analyses were conducted using the two key enzymes involved in oxalotrophy: formyl-coenzyme A (CoA) transferase (EC 2.8.3.16) and oxalyl-CoA decarboxylase (EC 4.1.1.8), encoded by the frc and oxc genes, respectively. Our analyses revealed that oxalate-degrading bacteria are restricted to three phyla, namely Actinobacteria, Firmicutes and Proteobacteria and originated from terrestrial, aquatic and clinical environments. Diversity analyses at the protein level suggest that total Oxc diversity is more constrained than Frc diversity and that bacterial oxalotrophic diversity is not yet fully described. Finally, the contribution of oxalotrophic bacteria to ecosystem functioning as well as to the carbon cycle is discussed. PMID:26748805

  18. Bacteria-powered battery on paper.

    Science.gov (United States)

    Fraiwan, Arwa; Choi, Seokheun

    2014-12-21

    Paper-based devices have recently emerged as simple and low-cost paradigms for fluid manipulation and analytical/clinical testing. However, there are significant challenges in developing paper-based devices at the system level, which contain integrated paper-based power sources. Here, we report a microfabricated paper-based bacteria-powered battery that is capable of generating power from microbial metabolism. The battery on paper showed a very short start-up time relative to conventional microbial fuel cells (MFCs); paper substrates eliminated the time traditional MFCs required to accumulate and acclimate bacteria on the anode. Only four batteries connected in series provided desired values of current and potential to power an LED for more than 30 minutes. The battery featured (i) a low-cost paper-based proton exchange membrane directly patterned on commercially available parchment paper and (ii) paper reservoirs for holding the anolyte and the catholyte for an extended period of time. Based on this concept, we also demonstrate the use of paper-based test platforms for the rapid characterization of electricity-generating bacteria. This paper-based microbial screening tool does not require external pumps/tubings and represents the most rapid test platform (<50 min) compared with the time needed by using traditional screening tools (up to 103 days) and even recently proposed MEMS arrays (< 2 days). PMID:25363848

  19. Anhydrobiosis in bacteria: From physiology to applications

    Indian Academy of Sciences (India)

    Armando Hernández García

    2011-12-01

    Anhydrobiosis is a phenomenon related to the partial or total desiccation of living organisms, keeping their vital functions after rehydration. The desiccated state in prokaryotes has been widely studied, mainly due to the broad spectrum of the anhydrobiosis applications. In this review, we present the basic theoretical concepts related to anhydrobiosis, focusing on bacterial species. An update about desiccation tolerance in bacteria is given; and the general mechanisms of desiccation tolerance and desiccation damage are described. In addition, we show how the study of anhydrobiosis in prokaryotes has established the theoretical and practical basis for the development of the drying technologies. With regard to the desiccation tolerance in bacteria, although many mechanisms remain undiscovered at the molecular level, important research about the physiology of the anhydrobiotic state and its applications has been performed, and here we provide the most recent information about this subject. On the other hand, the most widely used drying technologies and their particular applications in several fields are described (e.g. medicine, agriculture and food industry). Finally, topics on the stability of desiccated bacterial cells are treated, concluding with the necessity of focusing the research on the mathematical modelling of the desiccated state in bacteria.

  20. Bioleaching of marmatite using moderately thermophilic bacteria

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hong-bo; LIU Fei-fei; ZOU Ying-qin; ZENG Xiao-xi; QIU Guan-zhou

    2008-01-01

    The process of bioleaching marmatite using moderately thermophilic bacteria was studied by comparing marmatite leaching performance of mesophiles and moderate thermophiles and valuating the effect of venting capacity as well as pulp density on marmatite leaching performance of moderate thermophiles. The results show that moderate thermophiles have more advantages over mesophilies in bioleaching marmatite at 45℃ and the pulp density of 50g/L, and the zinc extraction efficiency reaches 93.1% in 20d. Aeration agitation can improve the transfer of O2 and CO2 in solution and promote the growth of bacteria and therefore, enhance the leaching efficiency. Under the venting levels of 50, 200 and 800mL/min, the zinc extraction efficiencies by moderate thermophiles are 57.8%, 92.5% and 96.0%, respectively. With the increase of pulp density, the total leaching amount of valuable metals increases, however, the extraction efficiency decreases due to many reasons, such as increasing shear force leading to poorly growth condition for bacteria, etc. The zinc extraction decreases remarkably to 58.9% while the pulp density mounts up 20%.

  1. Distribution of coliform bacteria in waste water

    Directory of Open Access Journals (Sweden)

    Dau Lal Bohra

    2012-02-01

    Full Text Available Biological activity of water can be apparently judged by the colonization of bacteria (microbes. In order to find out the extent of pollution and the relationship between inorganic matters and microbiota, a quantitative and qualitative analysis of bacteria in various types of sewage waters, namely sewage water by the residential colonies (group I, industrial waste water (group II, sewage treatment hub (group III, unorganized collected waste water (group IV and old residential waste collection center (group V, of Bikaner city (Rajasthan, India was carried out from February, 2010 to May, 2010. Water samples were taken from surface only owing to low depth and investigated for various abiotic factors (viz. transparency, pH, carbonate, bicarbonate, total alkalinity, total hardness, salinity, chloride, calcium, magnesium, sulphate, nitrate, silica, and inorganic phosphorous and biotic factors (viz. number and diversity of bacteria. The domestic sewage water causes major water borne diseases basing upon Total Bacterial Count (TBC and coliform Count (CC. The coliform count in the present study ranged from 2.5 to 5.12 MPN/mL. Comparision of microbial population in sewage water from all different Groups was done and the higher values of TBC and CC were recorded only in Sewage treatement hub (Group III.

  2. Bacteria associated with Amblyomma cajennense tick eggs.

    Science.gov (United States)

    Machado-Ferreira, Erik; Vizzoni, Vinicius Figueiredo; Piesman, Joseph; Gazeta, Gilberto Salles; Soares, Carlos Augusto Gomes

    2015-12-01

    Ticks represent a large group of pathogen vectors that blood feed on a diversity of hosts. In the Americas, the Ixodidae ticks Amblyomma cajennense are responsible for severe impact on livestock and public health. In the present work, we present the isolation and molecular identification of a group of culturable bacteria associated with A. cajennense eggs from females sampled in distinct geographical sites in southeastern Brazil. Additional comparative analysis of the culturable bacteria from Anocentor nitens, Rhipicephalus sanguineus and Ixodes scapularis tick eggs were also performed. 16S rRNA gene sequence analyses identified 17 different bacterial types identified as Serratia marcescens, Stenotrophomonas maltophilia, Pseudomonas fluorescens, Enterobacter spp., Micrococcus luteus, Ochrobactrum anthropi, Bacillus cereus and Staphylococcus spp., distributed in 12 phylogroups. Staphylococcus spp., especially S. sciuri, was the most prevalent bacteria associated with A. cajennense eggs, occurring in 65% of the samples and also frequently observed infecting A. nitens eggs. S. maltophilia, S. marcescens and B. cereus occurred infecting eggs derived from specific sampling sites, but in all cases rising almost as pure cultures from infected A. cajennense eggs. The potential role of these bacterial associations is discussed and they possibly represent new targets for biological control strategies of ticks and tick borne diseases. PMID:26537602

  3. Soil bacteria for remediation of polluted soils

    Energy Technology Data Exchange (ETDEWEB)

    Springael, D.; Bastiaens, L.; Carpels, M.; Mergaey, M.; Diels, L.

    1996-09-18

    Soil bacteria, specifically adapted to contaminated soils, may be used for the remediation of polluted soils. The Flemish research institute VITO has established a collection of bacteria, which were isolated from contaminated areas. This collection includes microbacteria degrading mineral oils (Pseudomonas sp., Acinetobacter sp. and others), microbacteria degrading polycyclic aromatic hydrocarbons (genera Sphingomonas and Mycobacterium), microbacteria degrading polychlorobiphenyls (genus Ralstonia and strains related to beta-Proteobacteria), and metal resistant bacteria with plasmid borne resistances to Cd, Zn, Ni, Co, Cu, Hg, and Cr. Bench-scale reactors were developed to investigate the industrial feasibility of bioremediation. Batch Stirred Tank Reactors were used to evaluate the efficiency of oil degraders. Soils, contaminated with non-ferrous metals, were treated using a Bacterial Metal Slurry Reactor. It was found that the reduction of the Cd concentration may vary strongly from sample to sample: reduction factors vary from 95 to 50%. Is was shown that Cd contained in metallic sinter and biologically unavailable Cd could not be removed.

  4. The analysis of bacteria strains and sensitivity of bacteria to antibiotics in acute obstructive cholangitis with suppuration

    Institute of Scientific and Technical Information of China (English)

    顾彬

    2013-01-01

    Objective To analyze the changes of bacteria stains in acute obstructive cholangitis with suppuration(AOSC) and sensitivity of different bacteria strains to antibiotics in recent decade. Methods The data of bacterial

  5. Bacteria-Targeting Nanoparticles for Managing Infections

    Science.gov (United States)

    Radovic-Moreno, Aleksandar Filip

    Bacterial infections continue to be a significant concern particularly in healthcare settings and in the developing world. Current challenges include the increasing spread of drug resistant (DR) organisms, the side effects of antibiotic therapy, the negative consequences of clearing the commensal bacterial flora, and difficulties in developing prophylactic vaccines. This thesis was an investigation of the potential of a class of polymeric nanoparticles (NP) to contribute to the management of bacterial infections. More specifically, steps were taken towards using these NPs (1) to achieve greater spatiotemporal control over drug therapy by more targeted antibiotic delivery to bacteria, and (2) to develop a prophylactic vaccine formulation against the common bacterial sexually transmitted disease (STD) caused by Chlamydia trachomatis. In the first part, we synthesized polymeric NPs containing poly(lactic-co-glycolic acid)-block-poly(L-histidine)-block-poly(ethylene glycol) (PLGA-PLH-PEG). We show that these NPs are able to bind to bacteria under model acidic infection conditions and are able to encapsulate and deliver vancomycin to inhibit the growth of Staphylococcus aureus bacteria in vitro. Further work showed that the PLGA-PLH-PEG-based NPs demonstrated the potential for competition for binding bacteria at a site of infection from soluble protein and model phagocytic and tissue-resident cells in a NP composition dependent manner. The NPs demonstrated low toxicity in vitro, were well tolerated by mice in vivo, and circulated in the blood on timescales comparable to control PLGA-PEG NPs. In the second part, we used PLGA-PLH-PEG-based NPs to design a prophylactic vaccine against the obligate intracellular bacterium Chlamydia trachomatis, the most common cause of bacterial STD in the world. Currently, no vaccines against this pathogen are approved for use in humans. We first formulated NPs encapsulating the TLR7 agonist R848 conjugated to poly(lactic acid) (R848-PLA

  6. Bacteria-Mineral Interactions on the Surfaces of Metal-Resistant Bacteria

    International Nuclear Information System (INIS)

    The extraordinary ability of indigenous microorganisms, like metal-resistant bacteria, for biotransformation of toxic compounds is of considerable interest for the emerging area of environmental bioremediation. However, the underlying mechanisms by which metal-resistant bacteria transform toxic compounds are currently unknown and await elucidation. The project's objective was to study stress-induced responses of metal-resistant bacteria to environmental changes and chemical stimulants. This project involved a multi-institutional collaboration of our LLNL group with the group of Dr. H.-Y. Holman (Lawrence Berkeley National Laboratory). In this project, we have utilized metal-resistant bacteria Arthrobacter oxydans as a model bacterial system. We have utilized atomic force microscopy (AFM) to visualize for the first time at the nanometer scale formation of stress-induced structures on bacterial surfaces in response to Cr (VI) exposure. We have demonstrated that structure, assembly, and composition of these stress-induced structures are dependent on Cr (VI) concentrations. Our AFM observations of the appearance and development of stress-induced layers on the surfaces of Arthrobacter oxydans bacteria exposed to Cr (VI) were confirmed by Dr. Holman's biochemical, electron microscopy, and synchrotron infrared spectromicroscopy studies. In general, in vitro imaging of live microbial and cellular systems represents one of the most challenging issues in application of AFM. Various approaches for immobilization of bacteria on the substrate for in vitro imaging were tested in this project. Imaging of live bacteria was achieved, however further optimization of experimental methods are needed for high-resolution visualization of the cellular environmental structural dynamics by AFM. This project enhanced the current insight into molecular architecture, structural and environmental variability of bacterial systems. The project partially funded research for two book chapters (1

  7. Assessment of the Levels of Airborne Bacteria, Gram-Negative Bacteria, and Fungi in Hospital Lobbies

    Directory of Open Access Journals (Sweden)

    Dong-Uk Park

    2013-01-01

    Full Text Available Aims: We assessed the levels of airborne bacteria, Gram-negative bacteria (GNB, and fungi in six hospital lobbies, and investigated the environmental and hospital characteristics that affected the airborne microorganism levels. Methods: An Andersen single-stage sampler equipped with appropriate nutrition plate agar was used to collect the samples. The three types of microorganisms were repeatedly collected at a fixed location in each hospital (assumed to be representative of the entire hospital lobby from 08:00 through 24:00, with a sampling time of less than 5 min. Temperature and relative humidity were simultaneously monitored. Results: Multiple regression analysis was used to identify the major factors affecting microorganism levels. The average levels of bacteria (7.2 × 102 CFU/m3, GNB (1.7 × 10 CFU/m3, and fungi (7.7 × 10 CFU/m3 indicated that all hospital lobbies were generally contaminated. Season was the only factor that significantly affected the levels of all microorganisms (p < 0.0001, where contamination was the highest during the summer, significantly higher than during the winter. Other significant factors varied by microorganism, as follows: airborne bacteria (number of people in the lobby, sampling time, GNB (scale of hospital, and fungi (humidity and air temperature. Conclusions: Hospital lobby air was generally contaminated with microorganisms, including bacteria, GNB, and fungi. Environmental factors that may significantly influence the airborne concentrations of these agents should be managed to minimize airborne levels.

  8. Isolation of radiation-resistant bacteria without exposure to irradiation

    International Nuclear Information System (INIS)

    Resistance to desiccation was utilized in the selection of highly radiation-resistant asporogenous bacteria from nonirradiated sources. A bacterial suspension in phosphate buffer was dried in a thin film at 250C and 33% relative humidity. Storage under these conditions for 15 days or more reduced the number of radiation-sensitive bacteria. Further selection for radiation-resistant bacteria was obtained by irradiation of bacteria on velveteen in the replication process, therby avoiding the toxic effect of irradiated media. The similarity of radiation resistance and identifying characteristics in irradiated and non-irradiated isolates should allay some concerns that highly radiation-resistance bacteria have been permanently altered by radiation selection

  9. Root Associated Bacteria – Friends or Enemies? A Review

    Directory of Open Access Journals (Sweden)

    Gabriela Mihalache

    2015-10-01

    Full Text Available Plant roots, due to their exudates, represent important ecological niches for bacteria, which can influence the plant growth by their both beneficial and deleterious effects. The positive effects of bacteria interaction with the plants roots consist in facilitating the nutrient uptake (N, P, producing phytohormones, enhancing their resistance to biotic and abiotic factors such as pathogenic fungi and bacteria, extreme temperatures, heavy metals, salinity. Regarding the harmful effects of bacteria on plants growth, production of phytotoxins, competition for nutrients or inducing diseases or even plants death represents examples of mechanisms by which bacteria can affect in a negative manner the growth of the plants.

  10. Prevalencia de bacterias causantes de mastitis en fincas lecheras de Toca (Boyacá, Colombia

    Directory of Open Access Journals (Sweden)

    Roy José Andrade-Becerra

    2015-04-01

    Full Text Available El presente trabajo tuvo como objetivo aislar las diferentes bacterias causantes de mastitis subclínica, de cuartos positivos a CMT (2+ o mayores a 300,000 cel/mL de vacas procedentes de fincas lecheras del municipio de Toca (Boyacá. Mediante un muestreo probabilístico de conveniencia y por medio de un estudio descriptivo longitudinal retrospectivo durante el año 2013, se estudiaron 130 fincas  especializadas en la producción de leche con promedios de 20 animales en lactancia por finca, ubicadas entre los 2300 y los 2800 msnm, con temperaturas anuales promedios de 13 °C y pluviosidades entre 800 y 1200 mm/año. Durante el año de estudio se encontró un 3.14% de cuartos positivos al CMT con grados superiores a 2 +. Streptococcus agalactiae se aisló en el 9,73%, y se convirtió en el principal patógeno aislado. Staphylococcus aureus fue aislado, en promedio, en el 6,00%. Corynebacterium bovis se aisló en el 0,30% de los casos. E. coli no se aisló. Mycoplasma bovis no se encontró en ninguna muestra. M. californicum se recuperó en el 0,50%. Levaduras, en el 0,20%, y Acholeplasma spp. se aisló en el 0,40%.

  11. Hessian fly-associated bacteria: transmission, essentiality, and composition.

    Directory of Open Access Journals (Sweden)

    Raman Bansal

    Full Text Available Plant-feeding insects have been recently found to use microbes to manipulate host plant physiology and morphology. Gall midges are one of the largest groups of insects that manipulate host plants extensively. Hessian fly (HF, Mayetiola destructor is an important pest of wheat and a model system for studying gall midges. To examine the role of bacteria in parasitism, a systematic analysis of bacteria associated with HF was performed for the first time. Diverse bacteria were found in different developmental HF stages. Fluorescent in situ hybridization detected a bacteriocyte-like structure in developing eggs. Bacterial DNA was also detected in eggs by PCR using primers targeted to different bacterial groups. These results indicated that HF hosted different types of bacteria that were maternally transmitted to the next generation. Eliminating bacteria from the insect with antibiotics resulted in high mortality of HF larvae, indicating that symbiotic bacteria are essential for the insect to survive on wheat seedlings. A preliminary survey identified various types of bacteria associated with different HF stages, including the genera Enterobacter, Pantoea, Stenotrophomonas, Pseudomonas, Bacillus, Ochrobactrum, Acinetobacter, Alcaligenes, Nitrosomonas, Arcanobacterium, Microbacterium, Paenibacillus, and Klebsiella. Similar bacteria were also found specifically in HF-infested susceptible wheat, suggesting that HF larvae had either transmitted bacteria into plant tissue or brought secondary infection of bacteria to the wheat host. The bacteria associated with wheat seedlings may play an essential role in the wheat-HF interaction.

  12. La importancia de los estudios sociales de la ciencia

    Directory of Open Access Journals (Sweden)

    Ezequiel Benito

    2010-10-01

    Full Text Available Pablo Kreimer es sociólogo por la Universidad de Buenos Aires y doctor en Ciencia, Tecnología y Sociedad del Centre Science, Technologie et Société de París. Realizó investigaciones en laboratorios de Francia, Inglaterra y Argentina. Sus temas de investigación incluyen la sociología e historia de la ciencia, las relaciones centro-periferia en la investigación científica, la relación entre problemas sociales y problemas de conocimiento y el desarrollo de campos académicos y disciplinares en América Latina. Actualmente, se desempeña como Investigador Independiente del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET. Es Profesor Titular de la Universidad Nacional de Quilmes (Argentina, donde dirige el Instituto de Estudios sobre la Ciencia y la Tecnología y la publicación científica REDES, Revista de Estudios Sociales de la Ciencia. Algunos de sus libros son: De probetas, computadoras y ratones: la construcción de una mirada sociológica sobre la ciencia (1999, L’Universel et le contexte dans la recherche scientifique (1999, Producción y uso social de conocimientos (2004, Culturas científicas e investigación agrícola en América Latina (2005, El científico también es un ser humano. La ciencia bajo la lupa (2009, Ciencia y periferia. Nacimiento, muerte y resurrección de la biología molecular en Argentina (2010. La presente entrevista aborda una serie de tópicos de central importancia para el desarrollo de un programa científico en psicología, que comprenden los modos en que se produce y aplica el conocimiento, un panorama sobre los estudios sociales de la ciencia en América Latina y el mundo, su impacto sobre las políticas científicas y tecnológicas, y el propio aporte de la ciencia psicológica a estos campos.

  13. Modelo de estudio de dos informativas familias colombianas con síndrome de usher

    OpenAIRE

    Tamayo ML.; González C; Gelvez N.

    2011-01-01

    Establecer y evaluar un modelo de abordaje para el estudio del Síndrome de Usher, que abarca el diagnóstico clínico de los pacientes, establecimiento y confirmación del subtipo mediante estudios moleculares y posterior correlación genotipo-fenotipo.

  14. Modelo de estudio de dos informativas familias colombianas con Síndrome de Usher

    Directory of Open Access Journals (Sweden)

    Tamayo ML.

    2001-06-01

    Full Text Available Establecer y evaluar un modelo de abordaje para el estudio del Síndrome de Usher, que abarca el diagnóstico clínico de los pacientes, establecimiento y confirmación del subtipo mediante estudios moleculares y posterior correlación genotipo-fenotipo.

  15. Design and application of the method for isolating magnetotactic bacteria

    Institute of Scientific and Technical Information of China (English)

    XIAO Zhijie; LIAN Bin; CHEN Jun; H. Henry Teng

    2007-01-01

    A simple apparatus was designed to effectively isolate magnetotactic bacteria from soils or sediments based on their magnetotaxis. Through a series of processes including sample incubation, MTB harvesting, isolation, purification and identification, several strains of bacteria were isolated from the samples successfully. By Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray Analysis (EDXA), these bacteria were certificated to be magnetotactic bacteria. The phylogenetic relationship between the isolated magnetic strains and some known magnetotactic bacteria was inferred by the construction of phylogenetic tree based on 16SrDNA sequences. This apparatus has been proven to have the advantages of being inexpensive, simple to assemble, easy to perform and highly efficient to isolate novel magnetotactic bacteria. The research indicated that the combined approach of harvesting MTB by home-made apparatus and the method of plate colony isolation could purify and isolate magnetotactic bacteria effectively.

  16. Computational Challenges in Characterization of Bacteria and Bacteria-Host Interactions Based on Genomic Data

    Institute of Scientific and Technical Information of China (English)

    Chao Zhang; Guo-lu Zheng; Shun-Fu Xu; Dong Xu

    2012-01-01

    With the rapid development of next-generation sequencing technologies,bacterial identification becomes a very important and essential step in processing genomic data,especially for metagenomic data.Many computational methods have been developed and some of them are widely used to address the problems in bacterial identification.In this article we review the algorithms of these methods,discuss their drawbacks,and propose future computational methods that use genomic data to characterize bacteria.In addition,we tackle two specific computational problems in bacterial identification,namely,the detection of host-specific bacteria and the detection of disease-associated bacteria,by offering potential solutions as a starting point for those who are interested in the area.

  17. Bacteria-bacteria interactions within the microbiota of the ancestral metazoan Hydra contribute to fungal resistance.

    Science.gov (United States)

    Fraune, Sebastian; Anton-Erxleben, Friederike; Augustin, René; Franzenburg, Sören; Knop, Mirjam; Schröder, Katja; Willoweit-Ohl, Doris; Bosch, Thomas C G

    2015-07-01

    Epithelial surfaces of most animals are colonized by diverse microbial communities. Although it is generally agreed that commensal bacteria can serve beneficial functions, the processes involved are poorly understood. Here we report that in the basal metazoan Hydra, ectodermal epithelial cells are covered with a multilayered glycocalyx that provides a habitat for a distinctive microbial community. Removing this epithelial microbiota results in lethal infection by the filamentous fungus Fusarium sp. Restoring the complex microbiota in gnotobiotic polyps prevents pathogen infection. Although mono-associations with distinct members of the microbiota fail to provide full protection, additive and synergistic interactions of commensal bacteria are contributing to full fungal resistance. Our results highlight the importance of resident microbiota diversity as a protective factor against pathogen infections. Besides revealing insights into the in vivo function of commensal microbes in Hydra, our findings indicate that interactions among commensal bacteria are essential to inhibit pathogen infection. PMID:25514534

  18. Estudio de los códigos QR

    OpenAIRE

    Gutiérrez García, Daniel

    2011-01-01

    El objetivo de este proyecto es el estudio de los Códigos QR para saber con exactitud, respecto a los tiempos de reacción y la distancia, las capacidades y características de los Códigos QR y el programa Barcode que esta basado en las librerías Zxing. Dichas libreras están creadas para las aplicaciones Android sobre un lenguaje en Java. De tal forma que en el futuro cualquier persona que quiera utilizar un código QR tenga una referencia de los tamaños de impresión de dicho código y a qu...

  19. Ordenanzas municipales de Ourense en el siglo XV: estudio introductorio

    Directory of Open Access Journals (Sweden)

    Enjo Babío, Ascensión

    2006-12-01

    Full Text Available The medieval municipal ordinances reflect the worry of the council by the daily problems and the decisions adopted to resolve them. In Ourense, a group of ordinances corresponding to the fifteenth century are preserved and they show the decisions adopted by the council in matter of urban and rural police, salubriousness, provision, funeral rites, etc. They permit also a detailed study about their structure and their elaboration procedure.

    La ordenanzas municipales medievales reflejan la preocupación del concejo por los problemas cotidianos y las decisiones adoptadas para resolverlos. En Ourense, se conservan un grupo de ordenanzas correspondientes al siglo XV que muestran las decisiones adoptadas por el concejo en materia de policía urbana y rural, salubridad, abastecimiento, exequias, etc., y que permiten un estudio detallado acerca de su estructura y procedimiento de elaboración.

  20. Hacia un esquema previo para el estudio del superdotado

    OpenAIRE

    Genovard Rosselló, Cándido

    1982-01-01

    Manca pdf al web original de la revista Se intenta una sencilla introducción a la temática del niño-adolescente superdotado desde dos perspectivas. En la primera se indica un posible marco de estudio desde la historia del problema, desde su definición, las distinciones sobre superdotado, niño con talento y niño creativo. En la segunda se indican algunos métodos de identificación, el papel de la orientación y el consejo, y se concluye con algunos consejos prácticos. A modo de apéncice se in...