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Sample records for bacterias aerobias aisladas

  1. RESISTENCIA A ANTIBIOTICOS DE BACTERIAS AISLADAS DE BIOPELÍCULAS EN UNA PLANTA DE ALIMENTOS

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    María Vanegas L

    2009-08-01

    Full Text Available Objetivo. Evaluar la resistencia a antibióticos y la capacidad de formación de biopelículas de bacterias aisladas en una planta de producción de alimentos. Materiales y métodos. Se tomaron muestras de 3 zonas diferentes, en una planta procesadora de alimentos; en la lavadora de canastas, la mesa de producción y en la banda empacadora. Se aislaron e identificaron las bacterias presentes en cada una de las tres zonas y se determinó la capacidad formadora de biopelículas por medio de cuantificación celular. Asimismo se evaluó la resistencia de cada una de las bacterias aisladas frente a ocho diferentes antibióticos. Resultados. Se recuperaron 29 cepas, correspondientes a 13 géneros diferentes, los cuales fueron todos formadores de biopelículas. Se encontró que cerca del 50% de las bacterias aisladas fueron resistentes a antibióticos como la penicilina G y vancomicina. Adicionalmente se evidenció un alto grado de multirresistencia a los diferentes antibióticos. Conclusiones. La alta multirresistencia encontrada a antibióticos entre las bacterias analizadas podría ser un problema para salud pública ya que pueden ser transmitidas por alimentos. De igual manera es de gran importancia la capacidad de producción de biopelículas de la microbiota analizada así como la alta concentración de bacterias entéricas y ambientales, lo que sugiere deficiencia del programa de limpieza y desinfección de la planta.

  2. Proteasas extracelulares producidas por bacterias marinas aisladas de aguas contaminadas con efluentes pesqueros

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    Tito Sánchez

    2013-06-01

    Full Text Available Un total de 26 cepas de bacterias marinas con actividad proteolítica fueron aisladas de agua de mar contaminadas con efluentes pesqueros; las mismas que se evaluaron en base al crecimiento y formación de halos de actividad en Agar Marino suplementados con caseína al 1%, pH 8,0 e incubados a 25 ºC por 72 h. Cinco cepas, seleccionadas por presentar los mejores halos de actividad fueron evaluadas a su vez por su crecimiento y producción de proteasas a diferentes concentraciones de NaCl, rangos de temperatura y pH; siendo consideradas finalmente como bacterias halotolerantes, psicrotróficas y alcalófilas moderadas. Estas cepas también fueron evaluadas por su actividad proteolítica específica sobre la caseína, siendo la cepa CM48 (Pseudomonas sp. la que presentó la mejor actividad específica (17,38 U/mg a las 72 horas, y seguidas por las cepas CM45 (Alcaligenes sp. (12,09 U/mg y tres cepas de Aeromonas sp. (CM43, CM44 y CM46 con valores de 12,02; 10,07 y 10,10 U/mg respectivamente.

  3. Evaluation of Petrifilm™ method for enumerating aerobic bacteria in Crottin goat's cheese Evaluación de PetrifilmTM para la enumeración de bacterias aerobias en queso de cabra Crottin

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    G.B. de Sousa

    2005-12-01

    Full Text Available The PetrifilmTM Aerobic Count Plate (ACP developed by 3M laboratories, is a ready-to-use culture medium system, useful for the enumeration of aerobic bacteria in food. PetrifilmTMwas compared with a standard method in several different food products with satisfactory results. However, many studies showed that bacterial counts in PetrifilmTM were significantly lower than those obtained with conventional methods in fermented food. The purpose of this study was to compare the PetrifilmTM method for enumerating aerobic bacteria with a conventional method (PCA in Crottin goat's cheese. Thirty samples were used for the colony count. The mean count and standard deviation were 7.18 ± 1.17 log CFU g-1 on PCA and 7.11 ± 1.05 log CFU g-1 on PetrifilmTM. Analysis of variance revealed no significant differences between both methods (t = 1.33, P = 0.193. The Pearson correlation coefficient (0.971, P=0.0001 indicated a strong linear relationship between the PetrifilmTM and the standard method. The results showed that PetrifilmTM is suitable and a convenient alternative to this standard method for the enumeration of aerobic flora in goat soft cheese.PetrifilmTM Aerobic Count Plate (ACP desarrollado por 3M es un sistema listo para usar, empleado para el recuento de bacterias aerobias en alimentos. PetrifilmTMfue comparado con los métodos estándar en diferentes productos alimenticios con resultados satisfactorios. Sin embargo, en alimentos fermentados, algunos estudios mostraron que el recuento de bacterias aerobias en PetrifilmTM fue significativamente menor que aquellos obtenidos con los métodos convencionales (PCA. El propósito de este estudio fue comparar el método PetrifilmTM para el recuento de bacterias aerobias con un método convencional en queso de cabra Crottin. Se usaron 30 muestras para el recuento de colonias. Las medias y desviaciones estándar fueron 7,18 ± 1,17 log UFC g-1 en PCA y 7,11 ± 1,05 log UFC g-1 en PetrifilmTM. El análisis de

  4. Biodegradación del explosivo tetranitrato de pentaeritritol (PETN por bacterias aisladas de ambientes mineros

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    Yerson Durán

    2013-12-01

    Full Text Available El tetranitrato de pentaeritritol (PETN es el detonante más energético y recalcitrante empleado en la actividad minera ya que posee cuatro grupos nitro unidos mediante enlaces éster; además es un contaminante orgánico persistente según el Convenio de Estocolmo. En el presente trabajo es evaluada la eficiencia de degradación del PETN por bacterias aisladas de ambientes mineros. En primer lugar se seleccionó las cepas con mayor crecimiento durante tres subcultivos en medio mínimo con PETN como única fuente de nitrógeno. Luego, se identificó mediante análisis del gen RNAr 16S las cepas Bacillus sp. J8A2 y Enterobacter sp. M1B. Las velocidades específicas de crecimiento fueron de 0.057 h -1 para J8A2 y 0.042 h -1 para M1B, y las velocidades específicas de degradación de 0.72 y 1.16 mmol de PETN/g de proteína.h, respectivamente. Además, el extracto crudo de la cepa J8A2 mostró una actividad específica (U de 1.03 mmol de PETN/h y una actividad específica por proteína (U/g de 138.6 mmol de PETN/g.h.

  5. Selección de bacterias con capacidad degradadora de hidrocarburos aisladas a partir de sedimentos del Caribe colombiano.

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    Narváez-Florez, S.; Gómez, M.L.; Martínez, M.M.

    2008-01-01

    A partir de sedimentos del Caribe colombiano se realizaron 31 aislamientos bacterianos en medio mínimo de sales suplementado con hidrocarburos (ACPM o petróleo crudo) como única fuente de carbono. Las cepas aisladas se sometieron a pruebas de selección en diferentes concentraciones de hidrocarburos y se escogieron once de ellas tolerantes al crudo y ACPM en un ámbito del 1-8% v/v. Posteriormente, con las cepas seleccionadas, se conformó un cultivo bacteriano mixto y se evaluó su capacidad de ...

  6. SELECCIÓN DE BACTERIAS CON CAPACIDAD DEGRADADORA DE HIDROCARBUROS AISLADAS A PARTIR DE SEDIMENTOS DEL CARIBE COLOMBIANO

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    Narváez-Flórez, Silvia; L. Gómez, Martha; Martínez, María M.

    2008-01-01

    A partir de sedimentos del Caribe colombiano se realizaron 31 aislamientos bacterianos en medio mínimo de sales suplementado con hidrocarburos (ACPM o petróleo crudo) como única fuente de carbono. Las cepas aisladas se sometieron a pruebas de selección en diferentes concentraciones de hidrocarburos y se escogieron once de ellas tolerantes al crudo y ACPM en un ámbito del 1-8% v/v. Posteriormente, con las cepas seleccionadas, se conformó un cultivo bacteriano mixto y se evaluó su capacidad de ...

  7. Actividad antimicrobiana de bacterias ácido lácticas aisladas de invertebrados marinos de la costa del Chubut (Patagonia – Argentina

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    Parada Romina

    2017-11-01

    Full Text Available Se estudió la actividad antagonista de cepas de bacterias ácido lácticas (BAL aisladas de invertebrados marinos de la costa del Chubut. Dentro de los 92 aislamientos, 22 exhibieron actividad, de las cuales 3 cepas se clasificaron como Lactobacillus y 19 como Enterococcus. En todos los casos, después de la neutralización con NaOH y tratamiento térmico, la actividad inhibitoria del sobrenadante libre de células de las cepas estudiadas permaneció activa. El tratamiento con lisozima y catalasa no afectó la actividad antimicrobiana; sin embargo la actividad enzimática de la tripsina abolió la acción inhibitoria de los sobrenadantes, confirmando la naturaleza proteica de los compuestos activos. Las actividades contra Listeria inocua ATCC 33090 logradas por cepas de Enterococcus variaron entre 640 y 163.840 unidades arbitrarias/mililitro (AU/ml, mientras que las cepas de Lactobacillus exhibieron actividades entre 20 y 40 AU/ml. Las cepas E. mundtii 278Pe, E. hirae 463Me y E. hirae 471Me exhibieron las actividades inhibitorias más altas contra un amplio espectro de bacterias patógenas y/o contaminantes de alimentos. A pesar de la amplia información disponible sobre estos microorganismos, existen pocos estudios de BAL aisladas a partir de invertebrados de origen marino. Los resultados obtenidos en este estudio sugieren que esta fuente puede contribuir al hallazgo de nuevas bacteriocinas con potencial uso en la industria alimentaria.

  8. Susceptibilidad de las bacterias aisladas de infecciones gastrointestinales agudas a la rifaximina y otros agentes antimicrobianos en México

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    O. Novoa-Farías

    2016-01-01

    Conclusiones: La resistencia de las bacterias enteropatógenas a antimicrobianos utilizados en gastroenteritis es alta. La rifaximina fue activa contra el 99-100% de las bacterias en concentraciones alcanzables en el contenido intestinal con las dosis recomendadas.

  9. Caracterización de bacterias halófilas productoras de amilasas aisladas de las Salinas de San Blas en Junín

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    Pamela Elizabeth Canales Mormontoy

    2014-07-01

    Full Text Available Título en español: Caracterización de bacterias halófilas productoras de amilasas aisladas de las Salinas de San Blas en Junín Título en ingles: Characterization of halophilic bacteria producing amylase isolated from San Blas Salterns in Junin Título corto: Bacterias halófilas amilolíticas de las Salinas de San Blas Resumen:  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 aproximadamente a 4100 m de altitud. Este estudio se realizó con 34 bacterias aisladas de muestras de suelos las cuales se cultivaron en agar agua de sales (SW 5 % conteniendo extracto de levadura 0,5 % y almidón 1 %. El 41 % de bacterias mostró la capacidad de hidrolizar almidón, éstas fueron caracterizadas mediante pruebas fisiológicas y bioquímicas convencionales. Tres bacterias fueron Gram-negativas y once Gram-positivas. El 21 % (3/14 creció en un amplio rango de concentración de sales, entre 5 y 20 %. El 14 % (2/14 de las bacterias presentó actividad lipolítica, proteolítica y nucleolítica, y el 29 % (4/14, presentó actividad proteolítica y nucleolítica. Las bacterias se identificaron mediante los perfiles de restricción de los genes ribosómicos 16S amplificados, las enzimas usadas fueron Hae III, BstU I, Hinf I y Cfo I. Los genes ribosómicos 16S de siete bacterias que presentaron perfiles de ADN diferentes se amplificaron, secuenciaron y analizaron mediante programas bioinformáticos. Del análisis fenotípico y molecular de las 14 bacterias amilolíticas se obtuvieron dos grupos, uno perteneciente al género Halomonas (3 y el otro, al género Bacillus (11. Las bacterias amilolíticas caracterizadas podrían ser de potencial uso a nivel industrial.  Palabras clave: Salinas de San Blas, amilasas, genes ribosómicos 16S, ARDRA, Bacillus, Halomonas. Abstract: The aim of this study was to characterize halophilic

  10. Evaluación del potencial biofertilizante de bacterias diazótrofas aisladas de suelos con cultivo de cacao (Theobroma cacao L.

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    Adriana Zulay Argüello-Navarro

    2014-09-01

    Full Text Available La adaptabilidad del cacao (Theobroma cacao L. en condiciones adversas permite sugerir que la microbiota asociada con la rizosfera desempeña una función importante para la nutrición y el desarrollo de la planta. En el trabajo se evaluó el potencial biofertilizante de bacterias fijadoras de nitrógeno (diazótrofas aisladas de suelos cacaoteros por la técnica de diluciones seriadas. Las bacterias se aislaron en medios semiselectivos (NFb, JMV, LGI, JNFb. Los aislados puros se caracterizaron morfológica y bioquímicamente y complementariamente se evaluó la capacidad de fijación biológica de nitrógeno (FBN por el método de Micro-Kjeldahl. Los aislados con mejor capacidad de fijación de nitrógeno fueron seleccionados para evaluar su potencial promotor de crecimiento durante 120 días en plantas de cacao clon CCN 51 establecidas a partir de semillas. El análisis de datos mostró que las plantas de cacao respondieron efectivamente a los tratamientos con bacterias donde las variables de crecimiento y N (% foliar incrementaron significativamente, en comparación con el testigo. Se destacó el aporte de los aislados DKA2J24, DKB3J73 presuntamente del género Burkholderia sp. y DKA1L3 semejante al género Gluconacetobacter sp., todos con un gran potencial como biofertilizantes en la prueba de bioensayo.

  11. Potencial biofertilizante de bacterias diazótrofas aisladas de muestras de suelo rizosférico

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    Laura Y Moreno

    Full Text Available Las bacterias promotoras del crecimiento vegetal son capaces de adaptarse, colonizar y persistir en la rizosfera de la planta, lo cual favorece su crecimiento y desarrollo. En este trabajo se aislaron 32 cepas nativas de bacterias diazótrofas, a partir de muestras de suelo rizosférico de diferentes cultivos, identificadas mediante los medios de cultivo tradicionales y el sistema BBL CRYSTAL. La identificación bioquímica se realizó a través de la reacción en cadena de la polimerasa (PCR, del inglés Polymerase Chain Reaction. Nueve aislados se determinaron como Stenotrophomonas maltophilia y uno como Azotobacter vinelandii, de los cuales tres coincidieron en la identificación bioquímica y la molecular. Se realizó un ensayo en invernadero para evaluar el efecto fertilizante en plantas de maíz, según un diseño experimental de bloques al azar y nueve tratamientos, por triplicado: tratamiento 1: A. vinelandii ATCC 9046; tratamientos del 2 al 7 para los seis aislados; tratamiento 8 para fertilización química; y tratamiento 9 para suelo sin fertilización (testigo. Los aislados M8-10, M10-1 y M11-3, identificados como S. maltophilia por PCR, tuvieron mejores resultados en la emergencia de las plantas, el diámetro del tallo y la longitud de las hojas y los tallos. Finalmente se determinó que M10-1 mostró valores de emergencia y crecimiento de la planta por encima de la media y el límite superior, con respecto a los demás aislados y controles, lo cual lo convierte en un potencial biofertilizante.

  12. CARACTERIZACIÓN DE BACTERIAS PROBIÓTICAS AISLADAS DEL INTESTINO GRUESO DE CERDOS COMO ALTERNATIVA AL USO DE ANTIBIÓTICOS

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    Henry Jurado G

    2009-08-01

    Full Text Available Objetivos. Caracterizar bacterias ácido lácticas probióticas aisladas del intestino grueso de cerdos adultos como posible alternativa al uso de antibióticos. Materiales y métodos. Se incluyeron muestras de intestino grueso de 20 cerdos adultos, para el aislamiento de bacterias lácticas (BAL. La caracterización de los parámetros bioquímicos-fisiológicos de las BAL contemplo la evaluación del pH del fermento, determinación de ácidos orgánicos por HPLC y detección de isómeros de ácido láctico. Los procedimientos microbiológicos evaluaron la capacidad de inhibición del crecimiento de patógenos y la actividad antagónica del probiótico vs antibiótico con su interacción competitiva. Se utilizaron pruebas API CHL 50 para la identificación de las BAL que se complementaron con la producción de gas, actividad de catalasa y viabilidad a diferentes concentraciones de sales biliares y temperaturas. Resultados. El plan de análisis permitió seleccionar dos aislados que se identificaron como: Lactobacillus plantarum 1 H1 y Lb. plantarum 1 H2. Las pruebas microbiológicas evidenciaron que las BAL seleccionadas inhibieron principalmente los enteropatógenos: Escherichia coli, Salmonella typhimurium y Clostridium perfringens. Las pruebas bioquímicas fueron compatibles con el género Lactobacillus, mostrando el siguiente perfil: Catalasa negativas; no productoras de gas; productoras de isómeros DL; resistentes a sales biliares y pH óptimo de crecimiento 3.5 a 38oC. Conclusiones. Los dos aislados de Lactobacillus plantarum 1 reunieron las características para el uso potencial como probióticos. Se recomienda su uso como complemento de terapias con antibióticos y en la elaboración de inóculos para aplicación en raciones alimenticias de lechones destetos, sin embargo, estudios complementarios se requieren para evaluar el efecto directo del probiótico como sustituto del uso de antibióticos in vivo.

  13. Antibiotic sensitivity of bacterial strains isolated from newborn infants Sensibilidad a los antibióticos de bacterias aisladas de neonatos hospitalizados

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    Alvaro Uribe

    1990-02-01

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    Eighty nine bacterial strains isolated from newborn infants hospitalized at a Special Care Unit in Medellin, Colombia, were studied. The sensitivity of each one was determined by the Minimallnhibitory Concentration method against 21 antibiotics; a high frequency of resistance was found toward gentamycin, netilmycin, oxacillin, penicillin G and ampicillin, that are often employed as initial therapy in newborn infants; on the other hand both Gram positive and Gram negative bacteria exhibited high percentages of sensitivity against quinolones; aztreonam and third generation cephalosporins were also highly effective against Gram negative bacilli. On the basis of this new information the need to restate therapeutic conducts in the case of serious bacterial neonatal infections is emphasized.

    Se estudiaron 89 cepas bacterianas aisladas de neonatos hospitalizados en la sala de cuidados especiales de la Fundación Hospitalaria San Vicente de Paúl, de Medellín; a cada una se le determinó la sensibilidad frente a 21 antibióticos por el método de la concentración inhibitoria mínima (CIM; se halló una alta frecuencia de resistencia hacia la gentamicina, la netilmicina, la oxacilina y la ampicilina que se usan a menudo en esta institución como terapia inicial en las infecciones del recién nacido; por otra parte se demostraron altos porcentajes de sensibilidad hacia las quinolonas tanto de las bacterias gram positivas como de las gram negativas; contra estas últimas también fueron muy efectivos el aztreonam y las cefalosporinas de tercera generación. A la luz de esta nueva información se llama la atención hacia la necesidad de revaluar las normas de la antibioterapia en las infecciones graves del recién nacido.

  14. Resistencia a los antimicrobianos en bacterias indicadoras y zoonóticas aisladas de animales domésticos en Argentina Antimicrobial resistance in indicator and zoonotic bacteria isolated from domestic animals in Argentina

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    F. L. Pantozzi

    2010-02-01

    Full Text Available Se estudiaron los patrones de resistencia a diversos antimicrobianos en bacterias indicadoras y zoonóticas aisladas de muestras fecales de individuos sanos, sin signología clínica, pertenecientes a los siguientes grupos animales: bovinos, equinos, ovinos, porcinos, gallinas ponedoras y caninos. Los antimicrobianos seleccionados fueron los empleados con mayor frecuencia en medicina veterinaria y humana, y el método de evaluación utilizado fue el de difusión en agar con discos. Los resultados obtenidos a partir de 240 Escherichia coli, 189 Enterococcus spp., 11 Campylobacter spp. y 2 Salmonella Gaminara (16:d:1,7, revelaron un mayor porcentaje de resistencia y multirresistencia en porcinos y aves, esto es, en animales de cría intensiva. El perfil de resistencia observado en los aislamientos de E. coli incluyó a la ampicilina, la estreptomicina, la tetraciclina y el ácido nalidíxico, en coincidencia con los antimicrobianos más utilizados en las explotaciones animales, al igual que lo detectado en Enterococcus spp. respecto a la tetraciclina y la eritromicina. Las cepas de Salmonella Gaminara (16:d:1,7 fueron sensibles a todos los antimicrobianos probados. En Campylobacter spp., si bien el número de aislamientos evaluados fue reducido, se observó una mayor resistencia a tetraciclina y quinolonas. Teniendo en cuenta la falta de datos en nuestro país sobre resistencia a los antimicrobianos en bacterias indicadoras y zoonóticas en animales domésticos, consideramos que la información obtenida podría utilizarse como punto de partida para futuros programas de monitoreo.Antimicrobial resistance profiles in indicator and zoonotic bacteria isolated from faeces of healthy animals without clinical signs of the following species: bovine, equine, ovine, porcine, layer hens, and canine, were studied. The chosen antimicrobials are frequently used in veterinary and human medicine. The agar diffusion was the method used. The obtained results of 240

  15. Bacterias ácido lácticas con capacidad antagónica y actividad bacteriocinogénica aisladas de quesos frescos

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    Cástulo I. Martín del Campo M.

    2008-01-01

    Full Text Available Se aislaron 350 cepas de bacterias ácido lácticas (BAL, a partir de 35 muestras de quesos frescos, fueron probadas en contra de cuatro microorganismos patógenos, tres Gram+ (Listeria monocytogenes, Staphylococcus aureus, Streptococcus pyogenes y un Gram- (Salmonella agona. Sólo 25 cepas mostraron capacidad antagónica, el mayor efecto inhibidor fue debido al pH, por la producción de ácidos orgánicos. 8 de ellas, mostraron un efecto inhibidor diferente al pH, Todas las cepas mostraron actividad antagónica en contra de bacterias Gram+. S. agona, no fue inhibida en su desarrollo, por ninguna de las cepas de bacterias ácido lácticas. Tres cepas que mostraron inhibición con el sobrenadante, se trataron con enzimas proteolíticas, y se determinó que el factor inhibidor es de origen proteico. 16 cepas mostraron que es necesaria la presencia de las BAL para inhibir a los patógenos, al probar el sobrenadante libre de BAL, el efecto inhibidor no se manifestó.

  16. Bacterias celulolíticas aisladas del intestino de termitas (Nasutitermes nigriceps con características probióticas y potencial en la degradación del pasto

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    Cecilia Lara Mantilla

    2013-06-01

    Full Text Available Título corto: Bacterias celulolíticas aisladas del intestino de termitas (Nasutitermes nigriceps  Título en ingles:  Cellulolytic bacteria isolated from  termites’ gut (Nasutitermes nigriceps with probiotic characteristics and potential pasture degradationResumen: El objetivo de la presente investigación fue aislar bacterias celulolíticas del intestino de termitas (Nasutitermes nigriceps para determinar sus propiedades probióticas in vitro y su potencial en la degradación de pasto. Las termitas fueron tratadas con detergente antibacterial, separando y macerando luego, el intestino de las mismas en agua peptonada estéril. Diluciones de esta mezcla fueron inoculadas en cajas Petri con medio Luria Bertani (LB y Carboximetilcelulosa (CMC al 2%, incubando a 37º C por 24 horas, para luego revelar con Rojo Congo al 1%. Las bacterias que presentaron mayores halos de degradación fueron sometidas a tinción de Gram y a pruebas probióticas de temperatura, pH, salinidad y presencia de sales biliares, así como también a pruebas de antagonismo y degradación de pasto. Los resultados revelaron la presencia de 9 bacilos celulolíticos Gram (- de los cuales, los bacilos BTN7 y BTN8, presentaron los mejores halos de degradación, 12 y 14 mm de diámetro respectivamente, creciendo adecuadamente en las diferentes pruebas probióticas con densidades entre 106 y 108 UFC/ml; el porcentaje de degradación de materia seca fue de 39.73% y 36.10% en 48 y 72 horas respectivamente.  Las pruebas bioquímicas API E (bioMérieux SA revelaron que los bacilos BTN7 y BTN8 pertenecen al género Enterobacter sp. Los anteriores resultados abren la posibilidad de emplear, estos microorganismos como aditivos en la alimentación de rumiantes, a fin de contribuir con un mayor aprovechamiento de pastos, y otros sustratos vegetales lignocelulósicos.Palabras claves: Probióticos, Maralfalfa (Pennisetum sp., microorganismos ruminales, lignocelulosa, Enterobacter

  17. Distribución de bacterias potencialmente fijadoras de nitrógeno y su relación con parámetros fisicoquímicos en suelos con tres coberturas vegetales en el sur de la Amazonia colombiana

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    Andrea J Mantilla-Paredes

    2009-12-01

    Full Text Available Se evaluó la abundancia y distribución de bacterias microaerófilas y aerobias potencialmente fijadoras de nitrógeno aisladas a partir de suelos bajo coberturas de bosque, pastizal y chagra en dos paisajes, terraza y llanura inundable, en el sur de trapecio amazónico. Se relacionó el recuento en placa en el medio Ashby de estas bacterias aerobias con las características físicas y químicas del suelo. Se encontró mayor abundancia de bacterias aerobias y microaerofilas en suelos bajo cobertura de pastizal. Se observó influencia directa del paisaje sobre la abundancia de bacterias microaerófilas registrando mayores recuentos los suelos bajo terraza en las coberturas de bosque y pastizal. Los aislamientos aerobios obtenidos (51 se agruparon en 19 morfologías, de las cuales se obtuvo mayor número en suelos bajo bosque y en el paisaje de llanura inundable. A través del análisis multidimensional no métrico (NMDS y análisis de similaridades (ANOSIM (pDistribution of potentially nitrogen-fixing bacteria and its relationship with physicochemical parameters in soils with three vegetation types in the southern Colombian Amazon region. Potentially nitrogen-fixing microaerobic and aerobic bacteria were isolated from several Colombian Amazon soils (forest, pastures and chagras and two landscapes (floodable and non floodable areas. The abundance and distribution of bacteria were evaluated, as well as their relationship with soil physical and chemical characteristics. Landscape had a direct influence on the abundance of the microaerobic bacteria, with higher numbers in forest and pasture soils in non- floodable zones. The aerobic isolates (N=51 were grouped into 19 morphologies, with the highest numbers found in forest soil in floodable zones. A higher number of aerobic morphologies was shared among forest sites (Nonmetric Multidimensional Scaling and Analysis of Similarity p<0.05, and 40% of the distribution was explained by lime percentage and

  18. Indicadores de calidad sanitaria y fenotipificación de Salmonella enterica aislada de pollo crudo comercializado en el área urbana de Mérida, Venezuela Sanitary quality indicators and phenotyping of Salmonella enterica isolated from raw chickens marketed in urban area of Mérida, Venezuela

    Directory of Open Access Journals (Sweden)

    Noreldy Molina

    2010-09-01

    Full Text Available Objetivo: Evaluar la calidad sanitaria del pollo crudo que se expende en supermercados del área urbana del estado Mérida, Venezuela, y caracterizar fenotípicamente las cepas aisladas de Samonella enterica. Materiales y métodos: Se estudiaron 45 muestras de pollo crudo (15 correspondieron a pollo sin aliños, 15 con aliños y 15 de origen industrial. Los indicadores de calidad sanitaria evaluados fueron: bacterias aerobias mesófilas, coliformes totales, Escherichia coli y Staphylococcus aureus, utilizando la metodología de la Comisión Venezolana de Normas Industriales. La identificación microbiológica y serológica de Salmonella spp. se realizó mediante técnicas convencionales. La sensibilidad antimicrobiana se determinó por concentración inhibitoria mínima (CIM y, para la detección de β-lactamasas de espectro expandido (BLEE, se utilizó la prueba del sinergismo del doble disco. La sensibilidad a desinfectantes se determinó por el método de dilución-neutralización. Resultados: Independientemente de las características de la muestra de pollo crudo (no industrial y del establecimiento comercial, los indicadores: bacterias aerobias mesófilas, coliforme totales, E. coli y S. aureus, superaron significativamente los recuentos límites de aceptabilidad. Salmonella enterica se aisló en 20% de las muestras, y las serovariedades Heidelberg (55,6% y Enteritidis (22,2% fueron las más frecuentes. Estas variedades serológicas presentaron multirresistencia y producción de BLEE, pero fueron sensibles a los desinfectantes probados. Conclusión: Los pollos crudos con aliños y sin ellos, manufacturados en los establecimientos estudiados, no cumplen con la calidad microbiológica adecuada, lo que hace de ellos un producto perecedero a corto plazo y un nicho favorecedor de patógenos importantes que amenazan la salud de los consumidores.Objectives: Evaluate the sanitary quality of raw chicken sold in the urban area of the State of Merida

  19. Instalación solar fotovoltaica aislada

    OpenAIRE

    Martínez Cerro, Bianca

    2011-01-01

    El objetivo de este proyecto es la creación e implementación de una instalación solar fotovoltaica aislada, con una autonomía de 5 días y un índice de ocupación del 100% durante todos los meses del año. Se prevé el consumo de una potencia diaria (Ed) de 7732W, para abastecer las necesidades primarias y energéticas de las 38 familias que conforman el poblado indígena EL PROGRESO, ubicado en el trapecio amazónico colombiano. De cara a futuras ampliaciones del sistema,...

  20. Presencia de sistemas de secreción de patógenos en bacterias endosimbióticas aisladas de Lupinus de la península Ibérica

    OpenAIRE

    Pastor, Víctor; Iglesias, Ana Isabel; Duran Wendt, David Ricardo; Rey Navarro, Luis

    2012-01-01

    Los rizobios son bacterias endosimbióticas capaces de fijar nitrógeno en estructuras especializadas de leguminosas. Esta simbiosis es altamente específica y depende, entre otros factores, de la capacidad de los rizobios de secretar proteínas efectoras a las células vegetales. Se han descrito diferentes sistemas de secreción en patógenos animales y vegetales y posteriormente también se han encontrado en algunos rizobios. En este trabajo se presenta el estudio de varios sistemas de secreción id...

  1. Bacterias celulolíticas aisladas del intestino de termitas (Nasutitermes nigriceps con características probióticas y potencial en la degradación del pasto

    Directory of Open Access Journals (Sweden)

    Cecilia Lara Mantilla

    2013-01-01

    Abstract: The objective of this research was to isolate cellulolytic bacteria from the gut of termites (Nasutitermes nigriceps to determine their probiotic properties in vitro and its potential in degrading  grass. Termites were treated with antibacterial detergent, then their intestine was separated and macerated in sterile peptone water. Dilutions of this mixture were inoculated in Petri dishes using  Luria Bertani (LB method and carboxymethylcellulose (CMC 2%, incubated at 37 ° C for 24 hours, and then revealed with 1% Congo Red. Bacteria with higher degradation halos were subjected to Gram staining and probiotic temperature tests, pH, salinity and the presence of bile salts, as well as antagonism and degradation of grass tests. The results revealed the presence of 9 Gram (-  cellulolytic bacillifrom which the bacilli BTN7 and BTN8, showed the best degradation halosof 12 and 14 mm in diameter respectively, growing suitably in the different probiotic tests with densities between 106 and 108 CFU / ml, the degradation percentages of dry matter was 39.73% and 36.10% within 48 and 72 hours respectively. Biochemical tests API E showed that (bioMérieux SA bacilli BTN8 and BTN7 belong to the genus Enterobacter sp. The above mentioned results open the possibility of using these organisms as additives for ruminants feeding, in order to contribute to a better use of pasture, and other lignocellulosic vegetal substrates. Key words:Probiotics, Maralfalfa (Pennisetum sp., ruminal microbes, lignocellulose, Enterobacter.

  2. Capacidad bactericida de Bifidobacterium sp. aislada de leche materna y de heces de neonatos, frente a los principales causantes de enfermedades transmitidas por alimentos

    OpenAIRE

    Vanegas, María Consuelo; González, Lina María; Arévalo, Stefany Alejandra

    2010-01-01

    Introducción. La microbiota del tubo digestivo humano contiene bacterias benéficas para la salud que regulan el funcionamiento del colon e inhiben algunos microorganismos patógenos intestinales. Las bifidobacterias aisladas de neonatos y de leche materna se usan como microorganismos probióticos para prevenir enfermedades infecciosas, incluidas las transmitidas por alimentos. Objetivo. Aislar e identificar Bifidobacterium sp. en humanos y determinar su capacidad bactericida frente a patógenos ...

  3. Evaluación de la diversidad de bacterias degradadoras de hidrocarburos aisladas de suelos de las cuencas de los ríos Otún y La Vieja / Evaluation of hydrocarbon degrading bacteria diversity isolated from soils of Otún and La Vieja river basins

    OpenAIRE

    Yanine Suárez, Habib Fernando

    2010-01-01

    Se evaluó el efecto del uso del suelo, sobre la densidad y diversidad de bacterias degradadoras de hidrocarburos (HC). Se seleccionaron los usos: bosque, pastizal y cafetal en la cuenca del río La Vieja (Valle del Cauca y Quindío), y bosque, cebollar y plantación forestal en la cuenca del río Otún (Risaralda) y se realizaron dos eventos de muestreo. La densidad se evaluó mediante la técnica de NMP en medio Bushnell-Hass, suplementado con diesel y usando XTT como indicador de actividad. Las ba...

  4. Instalación fotovoltaica aislada para una urbanización de viviendas

    OpenAIRE

    SIGNES MULET, VICENT

    2016-01-01

    El alumno realizará una instalación aislada para garantizar la alimentación eléctrica de las viviendas de una urbanización que están aisladas de la red eléctrica. Signes Mulet, V. (2016). Instalación fotovoltaica aislada para una urbanización de viviendas. http://hdl.handle.net/10251/76002. TFGM

  5. Optimización de un medio de cultivo para la producción de biomasa de la cepa Pseudomonas putida UA 44 aislada del suelo bananero de Uraba –Antioquia

    OpenAIRE

    Becerra Mejía, Camilo Andrés

    2007-01-01

    En el presente trabajo se diseñó y optimizó un medio de cultivo químicamente definido para la bacteria Pseudomonas putida UA44 con potencial PGPR aislada del suelo de la zona bananera de Uraba por Ramirez (2004). Los resultados obtenidos en el medio químicamente definido (MD) se compararon con los hallados en un medio de cultivo semicomplejo (TSB: Triptic Soy Broth por sus siglas en Ingles).

  6. Polihidroxialcanoatos de cepas de Azospirillum spp. aisladas de raíces de Lycopersicon esculentum Mill. “tomate” y Oryza sativa L. “arroz” en Lambayeque

    Directory of Open Access Journals (Sweden)

    Katty Baca

    2010-01-01

    Full Text Available En este trabajo se determinó la concentración de polihidroxialcanoatos (PH As de cepas de Azospirillum aisladas de raíces de Lycopersicon esculentum Mill. “tomate” y Oryza sativa L. “arroz”, como una alternativa ante la acumulación de plásticos derivados del petróleo. R aíces previamente desinfectadas se sembraron en medio Nfb se misólido, donde las bacterias fijadoras de nitrógeno se reconocieron por una película blanquecina bajo la superficie y el viraje del indicador al azul. El género Azospirillum se identificó en medio rojo de Congo, obteniéndose 96 cepas de A. lipoferum y A. brasilense en tomate y arroz. Se realizó una fermentación discontinua con caldo Azotobacter modificado, alimentando con una solución saturada de ácido málico cada 12 horas y se realizaron tinciones con Sudán Negro B. Se seleccionaron las cepas con mayor nú mero de gránulos de PHAs (en tomate , 18 de A. lipoferum y 2 de A. brasilense y en arroz, 10 de A. lipoferum y 10 de A. brasilense y se cuantificó la biomasa y PHAs. La concentración de PHAs alcanzó 0 . 661 gL - 1 en A. lipoferum KM(T - 73 y 0 . 738 gL - 1 en A. br asilense KM(T - 19. Las cepas de A. lipoferum y A. brasilense aisladas de tomate alcanzaron una mayor concentración de biomasa y PHAs frente a las cepas aisladas de arroz.

  7. Instalación fotovoltaica aislada para una instalación deportiva

    OpenAIRE

    BLEDA VALERO, JUAN JOSÉ

    2018-01-01

    El alumno realizará un completo estudio para diseñar una instalación fotovoltaica aislada de la red, que suministre la energía eléctrica a un centro deportivo. Incluyendo tanto el diseño de la instalación como el presupuesto para su ejecución. Bleda Valero, JJ. (2017). Instalación fotovoltaica aislada para una instalación deportiva. http://hdl.handle.net/10251/94105 TFGM

  8. Instalación solar fotovoltaica aislada para una industria de artes gráficas

    OpenAIRE

    MUÑOZ PRADES, ÓSCAR

    2018-01-01

    El alumno diseñará una instalación solar fotovoltaica aislada de la red eléctrica, para suministrar los consumos necesarios a una industria de artes gráficas. Realizando tanto el diseño de la instalación como su presupuesto y amortización. TFGM

  9. Cinética del proceso de depuración anaerobia de alpechín previamente biotratado vía aerobia

    Directory of Open Access Journals (Sweden)

    Borja Padilla, R.

    1991-06-01

    Full Text Available A kinetic study has been carried out on the process of anaerobic purification of an olive mill wastewater pre-treated aerobically to eliminate the greater part of the phenolic compounds responsible for inhibition. Two anaerobic digesters were used, one with Pansil support, and the other a Reference without filling. The aim was to study the influence of the immobilization support both on the biokinetic constants and on the efficiency of the anaerobic digestion process or biomethanization of this pre-treated olive mill wastewater. In contrast to what takes place with natural olive mill wastewater, only a very small decrease in the apparent rate constants of the anaerobic process was observed on increasing load density. At the same time, no inhibition was found in the biomethanization of this aerobically pre-treated wastewater.

    In contrast to what takes place with natural olive mill wastewater, only a very small decrease in the apparent rate constants of the anaerobic process was observed on increasing load density. At the same time, no inhibition was found in the biomethanization of this aerobically pre-treated wastewater. Se ha efectuado un estudio cinético del proceso de depuración anaerobia de un alpechín previamente tratado vía aerobia con objeto de eliminar la mayor parte de los compuestos fenólicos responsables de su poder inhibidor. Se utilizan dos reactores anaerobios, uno con soporte Pansil y un Testigo sin relleno, para estudiar la influencia del soporte de inmovilización tanto sobre las constantes biocinéticas como sobre la eficiencia del proceso de digestión anaerobia o biometanización de este alpechín pretratado. A diferencia de lo que ocurre con el alpechín natural, se observa sólo una pequeñísima disminución de las constantes aparentes de velocidad del proceso anaerobio al aumentar la densidad de carga. Por otra parte, no se aprecian fenómenos de inhibición en el proceso de biometanización de este agua

  10. Depuración aerobia de los efluentes resultantes del proceso de biometanización del alpechín

    Directory of Open Access Journals (Sweden)

    Borja Padilla, R.

    1992-02-01

    Full Text Available A study of aerobic treatment in batch regime of the effluents produced in the olive mill wastewater biomethanation process was carried out. An 83% of effluents organic substances was removal after the third day of fermentation. The substrate removal rate follows a zero-order kinetic for high concentrations, and a first-order kinetic for low organic matter concentration, during the last days of fermentation. The kinetic parameters (qmáx and K were obtained from Michaelis- Menten model.

    Se ha efectuado un estudio del proceso de depuración aerobia, en régimen discontinuo, de los efluentes procedentes del proceso de depuración anaerobia o biometanización del alpechín. Se comprueba que el 83% de la materia orgánica presente en este efluente se elimina a partir del tercer día de fermentación. La eliminación de sustrato sigue una cinética de orden cero para altas concentraciones del mismo y una cinética de primer orden para bajas concentraciones de materia orgánica, es decir, durante los últimos días de fermentación. Se aplica el modelo de Michaelis-Menten de eliminación de sustrato para la obtención de los parámetros cinéticos qmáx y Ks que rigen este proceso.

  11. Instalación Fotovoltaica Aislada para una Academia de Inglés

    OpenAIRE

    MARQUÉS MUÑOZ, ENRIQUE

    2017-01-01

    El objetivo de este trabajo final de grado, consiste en la elaboración de una instalación fotovoltaica aislada de una academia de inglés situada en la localidad valenciana de Masarrochos. Para ello, por mediación de contacto con el director del establecimiento y las facturas del último año facilitadas por el mismo, se ha podido determinar mediante la previsión de cargas una distribución aproximada de los consumos durante el ciclo anual. Marqués Muñoz, E. (2017). Instalaci...

  12. Efectos de la hindarina sobre las aurículas aisladas

    Directory of Open Access Journals (Sweden)

    Roberto Luis Rojas Martínez

    1997-12-01

    Full Text Available Se presentan los efectos de la hindarina y de la clorpromacina sobre la amplitud y la frecuencia de las contracciones espontáneas de las aurículas aisladas de rata. La hindarina produjo bradicardia moderada y aumento discreto de la amplitud de las contracciones en forma dosis-dependiente, en tanto que la clorpromacina deprimió más intensamente tanto la frecuencia como la amplitud de dichas contracciones. Se descartó una acción colinérgica o beta-bloqueadora en la producción de la bradicardia por la hindarina. Se descartó también una acción cardiotónica de la hindarina en las aurículas aisladas de cobayo deprimidas por solución hipocálcica o por hipoxia. Se sugiere su estudio como antiarrítmico.The effects of hindarine and of chlorpromazine on the amplitude and frequency of the spontaneous contractions of rats' isolated atria are presented. Hindarine produced a moderate bradycardia and a discreet increase of the contractions in a dosage-dependent way. Chlorpromazine caused a greater depression of the frequency and amplitude of these contractions. The cholinergic or beta-blocker action was discarded in the production of bradycardia brought about by hindarine. It was also eliminated a cadiotonic action of hindarine in the isolated atria of guinea pig depressed by hypocalcic solution or by hipoxia. It is suggested its study as an antiarrhythmic.

  13. Betalactamasas de espectro extendido tipo TEM y CTX-M en Klebsiella spp y Escherichia coli aisladas de superficies de ambientes hospitalarios

    Directory of Open Access Journals (Sweden)

    Marco Rivera-Jacinto

    Full Text Available El objetivo del estudio fue determinar el genotipo BLEE de 15 cepas de enterobacterias resistentes a betalactámicos, aisladas de superficies inanimadas y caracterizadas fenotípicamente como productoras de betalactamasas de espectro extendido. Previa evaluación y tamizaje de las cepas bacterianas, se hizo un PCR para amplificar fragmentos de 1078 pb y 544 pb correspondientes a BLEE tipo TEM y CTX-M. Once cepas presentaron ambos fragmentos a la vez y tres presentaron solamente blaCTX-M. En conclusión, se demostró la presencia de genes BLEE en cultivos de origen ambiental, algunos de los cuales podrían pertenecer a más de un tipo; esta información podría servir de base para implementar medidas de prevención que eviten la trasmisión de bacterias multirresistentes desde superficies inanimadas a los pacientes, principalmente en áreas hospitalarias críticas

  14. Prueba de sensibilidad antimicrobiana de cepas de Salmonella grupo D (móviles e inmóviles aisladas de ponedoras comerciales en Colombia

    Directory of Open Access Journals (Sweden)

    J. Jaime

    2010-12-01

    Full Text Available Las infecciones originadas por bacterias del género Salmonella son una de las principalescausas de pérdidas económicas en la industria avícola, se caracterizan generalmentepor la presentación de cuadros diarreicos y septicémicos que llevan a las aves a unamarcada disminución en la producción y a la muerte. En Colombia, debido al efectonegativo que produce Salmonella spp. en las aves, y con el objetivo de poder controlarla enfermedad, se utiliza una gran variedad de productos antimicrobianos, de loscuales no se posee suficiente información acerca de su comportamiento en cuanto asensibilidad y resistencia frente a las cepas de Salmonella spp. de campo. El objetivo deeste estudio fue determinar la respuesta de 20 cepas de Salmonella grupo D (móviles einmóviles aisladas de aves ponedoras comerciales en Colombia frente a diferentes antimicrobianos.Para su aislamiento y tipificación se utilizaron técnicas microbiológicasconvencionales, pruebas bioquímicas, serológicas y pruebas de susceptibilidad a losantibióticos por difusión en agar. Los resultados revelaron una resistencia total hacia laestreptomicina, seguida de altas resistencias para tetraciclina y florfenicol, y una menorresistencia a productos como fosfomicina y cloramfenicol.

  15. Prueba de sensibilidad antimicrobiana de cepas de salmonella grupo D (móviles e inmóviles aisladas de ponedoras comerciales en Colombia

    Directory of Open Access Journals (Sweden)

    J. Mantilla

    2010-01-01

    Full Text Available Las infecciones originadas por bacterias del género Salmonella son una de las principales causas de pérdidas económicas en la industria avícola, se caracterizan generalmente por la presentación de cuadros diarreicos y septicémicos que llevan a las aves a una marcada disminución en la producción y a la muerte. En Colombia, debido al efecto negativo que produce Salmonella spp. en las aves, y con el objetivo de poder controlar la enfermedad, se utiliza una gran variedad de productos antimicrobianos, de los cuales no se posee suficiente información acerca de su comportamiento en cuanto a sensibilidad y resistencia frente a las cepas de Salmonella spp. de campo. El objetivo de este estudio fue determinar la respuesta de 20 cepas de Salmonellas grupo D (móviles e inmóviles aisladas de aves ponedoras comerciales en Colombia frente a diferentes antimicrobianos. Para su aislamiento y tipificación se utilizaron técnicas microbiológicas convencionales, pruebas bioquímicas, serológicas y pruebas de susceptibilidad a los antibióticos por difusión en agar. Los resultados revelaron una resistencia total hacia la estreptomicina, seguida de altas resistencias para tetraciclina y florfenicol, y una menor resistencia a productos como fosfomicina y cloramfenicol.

  16. Instalación eléctrica de una vivienda unifamiliar aislada mediante suministro de energías renovables

    OpenAIRE

    LOZANO VALLADOLID, FERNANDO

    2015-01-01

    [ES] Instalación eléctrica con grado de electrificación elevada de una vivienda unifamiliar aislada mediante suministro de energías renovables (solar, eólica, geotérmicas). Lozano Valladolid, F. (2015). Instalación eléctrica de una vivienda unifamiliar aislada mediante suministro de energías renovables. http://hdl.handle.net/10251/58751. TFGM

  17. Estado de Salud infantil en las comunidades indígenas, afrocolombianas y aisladas en Colombia.

    Directory of Open Access Journals (Sweden)

    Francisco Nuñez L.

    2002-04-01

    Full Text Available

    Se estima que Sur América en la época precolombina tenía entre 7 y 39 millones de habitantes(1. Como consecuencia del descubrimiento y la conquista de América la población indígena fue diezmada en gran proporción; entre las causas adicionales que explican esta disminución en la población, se encuentran múltiples patologías de diverso origen. A pesar de la reducción importante de las poblaciones aisladas Colombia cuenta hoy con una amplia diversidad étnica que motivó al Instituto de Genética Humana de la Universidad Javeriana, con su proyecto de Expedición Humana (EH, a indagar sobre los problemas que afectan estos grupos humanos.

    Para cumplir este propósito los objetivos planteados fueron: realzar con elementos científicos la diversidad humana y cultural de nuestro país, prestar atención primaria en salud a las comunidades indígenas y afro colombianas diagnosticando sus principales problemas de salud e impulsando el desarrollo de proyectos que permitan el acceso de estas comunidades a los servicios de salud. Buscó también respuestas que puedan hacer aportes importantes al conocimiento universal para generar una conciencia de nuestra identidad biológica y cultural.

    El objetivo de este estudio es describir la frecuencia de las enfermedades más comunes, el estado nutricional, los antecedentes médicos, familiares y los hallazgos de la evaluación oftalmológica practicada a niños entre 0 y 18 años pertenecientes a 37 comunidades indígenas, afro colombianas y aisladas en Colombia.

    El proyecto, en lo que atañe a la evaluación del estado de salud infantil, cumple con los propósitos generales de la Expedición Humana y busca explicar la diversidad humana colombiana vista a través de la población infantil perteneciente a los grupos étnicos aislados que inicialmente poblaron nuestro territorio...

  18. Anaerobic bacteria

    Science.gov (United States)

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  19. Perfiles de resistencia a antibióticos y metales pesados en Pseudomonas aeruginosa potencialmente patógenas aisladas de agua de uso agrícola

    Directory of Open Access Journals (Sweden)

    Oscar G. Gutiérrez Cárdenas

    2017-01-01

    Full Text Available El 70% de l agua a nivel mundial se destina principalmente para las actividades agrícolas. Sin embargo, debido al crecimiento descontrolado de los asentamientos urbanos se ha acentuado la escasez y contaminación de los cuerpos de agua superficiales, de tal forma que cada vez este líquido de buena calidad es más escaso para la agricultura. Uno de los pri n cipa les contaminantes son las bacterias potencialmente patógenas resistentes a los antibiót i cos. Pseudomonas aeruginosa es una bacteria que se encuentra normalmente en el agua y suelo, es patógeno de animales y plantas. Esta bacteria se ha considerado un fenóm eno de resistencia debido a la diversidad de mecanismos que posee, por lo cual representa un rie s go potencial para la p o blación. Método : Se colectaron muestras de agua de uso agrícola, a partir de las cuales se aislaron e identificaron a nivel bioquímico y molecular P. aeruginosa . En estas bacterias se determinó la distribución de 6 genes de virulencia por PCR. Mediante ensayos de difusión en disco y m i crodilución se analizó la resistencia a 20 antibióticos. Además mediante ensayos de microd i lución se dete rminó la resistencia a metales pesados. Resultados : Se identificaron a nivel bioquímico y molecular 46 aislados de P. aeruginosa, éstas son potencialmente patógenas ya que en ellas se detectó la presencia de los genes de virule n cia algD y toxA (100%, las B (97.8%, plcH (95.6%, plcN (91.3% y exoS (89.1%. Dichas bacterias presentaron altos índices de resistencia a ampicilina, ceftriaxona, cloranfen i col, cefalotina, cefotaxima, nitrofurantoína, kanamicina , estreptomicina y tetraciclina. De igual forma fue ron muy susceptibles a ceftazidima, gentamicina, imipenem, ticarcilina, a z treonam, levofloxacina, netilmicina y carbenicilina. Todas las bacterias fueron multirresiste n tes ya que toleraron entre 8 y 11 antibióticos. De acuerdo a los patrones de resistencia obse r vados, las bacterias se

  20. Probiotic capacity of lactic acid bacteria isolated from chicha of molle

    OpenAIRE

    Rodríguez Carrasco, Jhanina; García-Godos Alcázar, Paula

    2017-01-01

    La investigación tuvo como objetivos aislar e identificar bacterias lácticas (BAL), evaluar la capacidad probiótica in vitro e in vivo de bacterias lácticas aisladas de chicha de molle, para ello se muestreó chichas de molle elaboradas artesanalmente de las provincias de Huanta y Huamanga, aislando 55 cepas BAL e identificando a Lactobacillus plantarum, Lactobacillus maltaromicus y Leuconostoc mesenteroides en base a la coloración Gram, producción de gas, gluconato y fermentación de azúcares....

  1. Especies de Malassezia aisladas de pacientes con lesiones dermatológicas

    Directory of Open Access Journals (Sweden)

    Sandra Rincón

    2005-06-01

    Full Text Available Introducción. Las levaduras del género Malassezia forman parte de la flora normal de la piel y se asocian con varios tipos de lesiones dermatológicas. Desde 1996, la descripción de nuevas especies dentro de este género planteó numerosos interrogantes sobre su epidemiología y patogenicidad. Objetivo. El fin de este trabajo fue encontrar la frecuencia de las diferentes especies de Malassezia en individuos con pitiriasis versicolor, dermatitis atópica, dermatitis seborreica, dermatitis seborreica en pacientes positivos para VIH, y en individuos sin lesiones a partir de tres zonas corporales (cabeza, tórax, extremidades inferiores y superiores. Materiales y métodos. Se identificaron 154 aislamientos de especies de Malassezia de 112 individuos: 39 con dermatitis seborreica de los cuales 20 eran positivos para VIH, 18 con pitiriasis versicolor, 18 con dermatitis atópica y 37 individuos sin lesión dermatológica (controles. Las escamas de piel de los pacientes se observaron microscópicamente y las muestras de pacientes y controles se cultivaron en agar Dixon modificado. Posteriormente, se observaron las colonias y se identificaron según sus características macroscópicas, microscópicas y fisiológicas. Resultados. Las especies más frecuentemente aisladas en el total de los grupos estudiados fueron: Malassezia globosa (37,5%, M. sympodialis (31,3% y M. furfur (31,3%. M. globosa predominó en los aislamientos de pacientes con pitiriasis versicolor (67% y en pacientes positivos para VIH con dermatitis seborreica (85%. En pacientes con dermatitis atópica y dermatitis seborreica sin diagnóstico de VIH, se aislaron M. furfur y M. restricta en el 72% y el 26% de los casos, respectivamente. Conclusiones. Las diferentes especies de Malassezia pueden aislarse de pacientes con lesiones dermatológicas o sin ellas. Además, la frecuencia de especies en la población muestreada difiere de lo reportado en otras zonas geográficas. Se destaca la

  2. Incidencia y fármaco-resistencia de cepas de Staphylococcus spp aisladas de exudados conjuntivales Incidence and drug-resistance of Staphylococcus spp strains isolated from conjunctival swabs

    Directory of Open Access Journals (Sweden)

    Andrés Noya Cabaña

    2010-01-01

    Full Text Available OBJETIVO: Determinar la incidencia de cepas del género Staphylococcus aisladas de exudados conjuntivales y analizar su resistencia frente a diferentes antimicrobianos. MÉTODOS: Se realizó un estudio observacional descriptivo retrospectivo en el que se revisaron 3554 exudados conjuntivales a pacientes que acudieron en el período comprendido entre enero de 2002 a diciembre de 2003 y desde enero de 2005 hasta diciembre de 2007 al Instituto Cubano de Oftalmología «Ramón Pando Ferrer» por presentar un diagnóstico de infección ocular externa. RESULTADOS: Se aislaron 874 cepas de Staphylococcus aureus para un 47,5 % y 965 cepas de Staphylococcus spp. coagulasa negativa con prueba de patogenicidad positiva para un 52,4 %. En 69 de esos exudados los cultivos presentaron etiología mixta con dos bacterias diferentes, para el 3,7 %. Se determinaron los porcentajes de resistencia a las cepas aisladas pertenecientes al género Staphylococcus. CONCLUSIONES: Se encontró una alta incidencia de las especies del género Staphylococcus en las infecciones oculares, así como se pudo apreciar que la menor fármaco-resistencia para Staphylococcus aureus y Staphylococcus spp. coagulasa negativa correspondieron a los antimicrobianos ciprofloxacina y amikacina. La mayor fármaco-resistencia de las cepas de Staphylococcus aureus correspondió a eritromicina y tetraciclina y en Staphylococcus spp coagulasa negativa fue frente a la tetraciclina.OBJECTIVE: To determine the incidence of Staphylococcus strains isolated from conjunctival swaps and their resistance to several antimicrobial agents. METHODS: A retrospective, descriptive and observational study was performed to review 3554 conjunctival swabs from patients who went to "Ramón Pando Ferrer" Institute of Ophthalmology in the period from January 2002 to December 2009 due to a diagnosis of external ocular infection. RESULTS: From the total of conjunctival swabs, 874 Staphylococcus aureus strains (47.5 % and

  3. Caracterización molecular de serovariedades de Leptospira spp. aisladas de muestras de animales y agua en Colombia

    Directory of Open Access Journals (Sweden)

    Claudia M. Romero-Vivas

    2013-08-01

    Full Text Available Introducción. La leptospirosis es una infección bacteriana transmitida directa o indirectamente de animales a humanos, la cual puede resultar en una enfermedad hemorrágica grave, hepática o renal y pulmonar. Hay 20 especies de Leptospira conocidas y cientos de serovariedades, algunas de las cuales pertenecen a diferentes especies. Es esencial identificar las serovariedades patógenas y sus reservorios potenciales para enfocar estrategias de control. Objetivo. Caracterizar las serovariedades de Leptospira aisladas de muestras de roedores, perros, cerdos y agua en Colombia. Materiales y métodos. Las cepas de leptospiras aisladas fueron identificadas como patógenas usando la reacción en cadena de la polimerasa (PRC. Sus ADN y el ADN de Salmonella Braenderup H9812 (marcador de peso molecular fueron cortados con NotI y corridos en electroforesis de campo pulsado. Los patrones de la ECP se analizaron con base en los criterios de tipificación para cepas bacterianas y el coeficiente de Dice, cuando se compararon con 200 cepas aisladas en otras partes del mundo. Los perfiles de ADN con un coeficiente de Dice entre 73,7 % y 100 % se consideraron pertenecientes a la misma especie. Resultados. Todos los aislamientos fueron cepas patógenas y cinco se caracterizaron genéticamente. El aislamiento P275 (coeficiente de Dice: 84 % y el P282 (coeficiente de Dice: 95 % de cerdos, se relacionaron con Leptospira interrogans de serovariedad Pomona; el aislamiento de rata (I15 fue indistinguible de Leptospira interrogans de serovariedades Icterohaemorrhagiae o Copenhageni (coeficiente de Dice: 100 %, mientras que los aislamientos de perro (C67 y agua (A42 no se relacionaron (coeficiente de Dice <73,7 % con ninguna de las 200 cepas de referencia; las más cercanas fueron Leptospira noguchii de serovariedades Nicaragua (coeficiente de Dice: 63 % y Orleans (coeficiente de Dice: 60 %. Conclusiones. Esta fue la primera caracterización molecular de serotipos de

  4. Presencia de B-lactamasas de espectro extendido en enterobacterias aisladas de casos de infección nosocomial

    Directory of Open Access Journals (Sweden)

    Sergio Pavón Romero

    2011-01-01

    Full Text Available Las enterobacterias son los microorganismos etiologicos mas frecuentemente asociados a las infecciones nosocomiales (in, caracterizandose por su alta resistencia a los antibioticos B-lactamicos, mediada por la produccion de B-lactamasas de Espectro Extendido (blee. Su uso excesivo aumenta la seleccion de cepas multirresistentes, favoreciendo su propagacion e incremento de las complicaciones de casos de in. En algunos casos las cepas productoras de blee presentan resistencia adicional a aminoglucosidos, quinolonas, tetraciclinas y trimetoprim-sulfametoxazol, reduciendo las opciones terapeuticas de las in. Con la finalidad de conocer localmente la magnitud de este problema, se estudiaron 87 cepas de enterobacterias aisladas de casos de in, encontrandose que el 26.43% son productoras de blee y en este caso fenotipicamente multirresistentes.

  5. The establishment of new control parameters in the aerobic stabilisation of sludge; Establecimiento de nuevos parametros de control en la estabilizacion aerobia de lodos

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Sanchez, J.; Coello Oviedo, M. D.; Cruz Romero, F. J.; Quiroga Alonso, J. M.

    2002-07-01

    This article presents the results obtained in an aerobic sludge digestion process in a conventional waste water treatment plant employing the usual parameters in this type of study as discussed in the literature. The physicochemical parameters used were pH dissolved oxygen, temperature. Chemical Demand for Oxygen (DOQ) total solids (TS) and volatile solids (VS), while the microbiological parameters were fecal coliforms Escherichia coli (EC) and the active and total bacteria counts. The enzymatic parameters examined were the specific oxygen uptake rate (SOUR). In dehydrogenase (DHA) activity and esterase activity (EA). The results obtained permit the conclusions that although physicochemical parameters provide information on the system's performance, they are neither indicative of the degree of endogenesis attained nor representative of the factors affecting the process. The microbiological parameters, on the other hand, are valid as measurements of the evolution of the populations and of the factors affecting them, but are not representative of the endogenous breathing process. besides which they also present problems of quantification. Finally, the enzymatic parameters, dehydrogenase activity and, especially, the DHA/EA ratio, are an efficient tool. Since they are representative of the metabolic state of the sludge, it is possible to establish criteria regarding its stability in relation to the mixed feed sludge. (Author) 11 refs.

  6. Diseño de una instalación fotovoltaica para una vivienda aislada con posibilidad de compra-venta a red

    OpenAIRE

    Subiza Betelu, Sara

    2014-01-01

    Este proyecto fin de carrera tiene como objetivo el diseño de una instalación fotovoltaica para una vivienda aislada con conexión a red, y la evaluación de la viabilidad tanto técnica como económica de la instalación. Esta instalación estará situada en el tejado de una vivienda aislada, que se encuentra en el término municipal de Ariz (Navarra). El proyecto tiene como finalidad la autonomía energética de dicha vivienda y la posibilidad de compra-venta a red de la energía eléctrica. Se a...

  7. Antimicrobial susceptibility test in Brachyspira pilosicoli strains isolated from commercial layers farms in Colombia PRUEBAS DE SENSIBILIDAD FRENTE A AGENTES ANTIMICROBIANOS EN CEPAS DE Brachyspira pilosicoli AISLADAS A PARTIR DE PONEDORAS COMERCIALES EN COLOMBIA

    Directory of Open Access Journals (Sweden)

    Figueroa Ramìrez Judith

    2009-04-01

    Full Text Available Intestinal Spirochaetes of the genus Brachyspira cause important diseases in swine and poultry. An increasing problem in the presentation of resistant strains to the antimicrobial drugs usually used to treat the intestinal spirochaetosis in swine has been evidenced and this could be applicable to the isolations from poultry. There are very few reports of in vitro antimicrobial susceptibility of Brachyspira spp. isolated from birds. In this study the antimicrobial susceptibility of twelve Brachyspira pilosicoli isolates obtain from commercial layers was evaluated against tiamulin, tylosin and lincomycin establishing the Minimum Inhibitory Concentration (MIC by agar dilution technique. All bacteria analyzed were sensitive to tiamulin (MIC ≤0,1μg/ml, and lincomycin (MIC 1μg/ml and resistant to tylosin (MIC 5μg/ml.Las espiroquetas intestinales del género Brachyspira ocasionan enfermedades importantes en porcinos y aves. Se ha evidenciado un problema de incremento en la presentación de cepas resistentes a los antimicrobianos utilizados normalmente para tratar las espiroquetosis intestinales en porcinos, y esto podría ser aplicable a los aislamientos de aves. Hay muy pocos reportes de sensibilidad antimicrobiana in vitro de cepas de Brachyspira spp. Aisladas en aves. En este estudio se evaluó la sensibilidad de doce aislamientos de Brachyspira pilosicoli obtenidos de granjas de ponedoras comerciales a los agentes antimicrobianos tiamulina, tilosina y lincomicina, y se estableció la concentración mínima inhibitoria (CMI mediante la técnica de dilución en agar. Todas las bacterias analizadas fueron sensibles a tiamulina (CMI ≤0,1 μg/ml y lincomicina (CMI 1 μg/ml y resistentes a tilosina (CMI 5 μg/ml.

  8. Cirugía de mínimo acceso de la fibrilación auricular aislada

    Directory of Open Access Journals (Sweden)

    Aquilino Hurlé

    2008-10-01

    Full Text Available La fibrilación auricular es el trastorno del ritmo cardíaco más frecuente. Durante años, su tratamiento se vio limitado casi exclusivamente al control farmacológico de la frecuencia cardíaca y a la prevención de eventos tromboembólicos con fármacos anticoagulantes. Debido a los recientes avances en el campo de la electrofisiología cardíaca y al desarrollo tecnológico, el abordaje terapéutico de esta arritmia se contempla hoy en día desde una perspectiva mucho más intervencionista que antaño. Recientemente, técnicas de cirugía videoasistida de última generación han comenzado a ser aplicadas en el tratamiento de la fibrilación auricular aislada con dos modalidades de abordaje: la cirugía mediante miniincisiones (minitoracotomía y la cirugía toracoscópica propiamente dicha. En este artículo describiremos y comentaremos estas formas de tratamiento quirúrgico de la fibrilación auricular.

  9. Capacidad de invasión de los eritrocitos de pollo de una cepa de Mycoplasma synoviae aislada en Argentina

    OpenAIRE

    Uriarte, Javier; Cerdá, Raúl Oscar; Stanchi, Néstor Oscar

    2015-01-01

    Mycoplasma synoviae es uno de los patógenos más importantes en la industria de aves de corral y a menudo causa enfermedades de naturaleza crónica. Poco se sabe acerca de los mecanismos de persistencia en el hospedador y las cepas difieren significativamente en la invasividad y patogenicidad. Un estudio reciente demostró la capacidad de M. synoviae para invadir los eritrocitos de pollo (CER). El objetivo de este estudio fue determinar si una cepa de campo de M. synoviae, aislada de una granja ...

  10. Analisis tecnico, socioeconomico y ambiental de la electrificación con energía solar fotovoltaica aislada para vivienda rural en Hato Corozal, Casanare, Colombia

    OpenAIRE

    Edwin Blasnilo Rúa Ramírez; Andrea Isabel Barrera Siabato; Martín Gómez Orduz

    2017-01-01

    La electrificación con energía solar fotovoltaica aislada es la opción más viable para vivienda rural, en especial si se encuentra muy distante del sistema nacional interconectado. Hato Corozal, Casanare, Colombia, es un municipio estructurado en su área rural por fincas muy alejadas entre sí. Su mayor inconveniente de desarrollo social y económico es la falta de electricidad como servicio de primera necesidad.  La gobernación de Casanare a través del fondo nacional de regalías aprobó la inst...

  11. Identificación y caracterización de especies de Neosartorya aisladas de frutillas (Fragaria spp.) frescas y tratadas térmicamente

    OpenAIRE

    Laura Frisón; Silvina Sobrero; Juan De Jesús; María de Basílico; Juan Basílico

    2012-01-01

    El género Aspergillus es uno de los géneros fúngicos más estudiados y de gran impacto a nivel industrial. La sección Fumigati incluye unas pocas especies anamorfas del género Aspergillus. Las especies que son teleomorfas se encuentran dentro del género Neosartorya. Este es un moho resistente al calor que causan problemas en las industrias alimentarias o enfermedades en los seres humanos. Sus ascosporas han sido aisladas a partir de frutas, pulpas y jugos, ya que pueden sobrevivir a los tratam...

  12. 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...

  13. 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...... 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 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size...

  14. Magnetic Bacteria.

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    1992-01-01

    Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)

  15. Degradación de Fenantreno por bacterias del género Burkholderia y Rhizobium aisladas de nódulos de mimosas

    Directory of Open Access Journals (Sweden)

    Arnoldo Wong-Villarreal

    2017-01-01

    Full Text Available El presente trabajo tuvo como objetivo identificar y evaluar la capacidad de degradación de microorganismos aislados de nódulos de mimosas, que puedan ser utilizados en procesos de biorremediación de suelos contaminados con fenantreno . Método . Se realizó el aislamiento de 122 cepas bacterianas de nódulos de mimosas; fueron crecidas en el medio de cultivo Maconkey para descartar enterobacterias. L as cepas bacterianas que dieron resultado negativo a esta prueba, fueron inoculadas en el medio de cultivo que contenía como úni ca fuente de carbono fenantreno; tres aislados tuvieron la capacidad de crecer en este medio. Las tres cepas fueron identificadas por secuencia del gen 1 6s ribosomal, se evaluó su capacidad de crecimiento en presencia de fenantreno mediante curvas de crecimiento microbiano; la capacidad para degradar fenantreno de las tres cepas fue cuantificada por cromatografía de gases acoplado a masas. Resultados . La s secuencias obtenidas del gen 16s ribosomal tienen relación genética con las especies de Burkholderia phenoliruptrix , Burkholderia phymatum y Rhizobium paknamense. El crecimiento microbiano de las tres cepas, suministradas con fenantreno, tuvieron un comp ortamiento similar al control , el cual contenía succinato como fuente de carbono. La cepa de Burkholderia sp. BB26 degradó 78.5 % , Burkholderia sp. BB24 68.5 % y Rhizobium sp. BY8 99%. Discusión . Los resultados de degradación de fenantreno por las cepas de Burkholderia sp. BB26 , Burkholderia sp. BB24 y Rhizobium sp. BY8 sugieren que las tres cepas tienen p otencial para utilizarse en procesos de biorremediación de suelos contaminados con fenantreno.

  16. Carotenogénesis de cinco cepas del alga Dunaliella sp. (Chlorophyceae aisladas de lagunas hipersalinas de Venezuela

    Directory of Open Access Journals (Sweden)

    Miguel Guevara

    2005-09-01

    Full Text Available Se realizaron cultivos discontinuos (medio Algal con 0.5 mM de NaNO3 y 27% de NaCl de cinco cepas de Dunaliella sp., aisladas de diferentes lagunas hipersalinas de Venezuela (Araya, Coche, Peonía, Cumaraguas y Boca Chica y una cepa de referencia (Dunaliella salina LB1644. Los bioensayos se mantuvieron a 25 ± 1 °C con aireación constante, fotoperiodo 12:12 y dos intensidades luminosas (195 y 390 µE.m-2.s-1 durante 30 días. El crecimiento celular se determinó diariamente mediante conteo celular en cámara de Neubaüer. La clorofila a y los carotenoides totales se analizaron al final del ensayo. Las mayores densidades celulares correspondieron a los ensayos de menor intensidad luminosa. La cepa que alcanzó la mayor densidad celular fue la aislada de Boca Chica (8 x10(6 y 2.5 x10(6 cel.ml-1 a 195 y 390 µE.m-2.s-1, respectivamente. El incremento de la intensidad luminosa en los cultivos produjo una disminución significativa de las tasas de crecimiento en todas las cepas. Los carotenoides totales por volumen fueron mayores a 390 µE.m-2 .s-1; siendo las cepas de referencia LB1644, Coche y Araya las que produjeron mayor cantidad (38.4; 32.8 y 21.0 µg.ml-1, respectivamente. El contenido de carotenoides totales por célula en los dos tratamientos fue significativamente diferente, obteniéndose la mayor concentración a 390 µE.m-2.s-1. Las cepas LB1644 y Coche fueron las que produjeron los valores más altos de carotenos (137.14 y 106.06 pg.cel-1, respectivamente. La cepa LB1644 presentó la mayor relación carotenoides totales:clorofila a (20:1 a 195 µE.m-2.s-1, mientras que en la cepa Coche no se evidenciaron diferencias significativas entre las dos intensidades (15:1. El resto de las cepas mostraron relaciones inferiores a uno. Nuestros resultados sugieren que las cepas Coche y Araya pueden ser potencialmente utilizadas en la biotecnología de producción de carotenoides.Carotenogenesis of five strains of the algae Dunaliella sp

  17. “Corrosión Inducida por Bacterias Sulfato Reductoras Termófilas de 60°C en la Unión Soldada del Acero API 5L- X60.”

    OpenAIRE

    Romero Romero, Justo Román

    2012-01-01

    En esta investigación se estudio el efecto de la corrosión inducida por Bacterias Sulfato Reductoras (BSR) termófilas a 60oC en el metal base (MB) y la unión soldada (US) del acero API X-60. Las bacterias sulfato reductoras fueron aisladas en el medio sólido postgate con la técnica de estriado, y fueron resembradas hasta obtener la misma morfología. El medio postgate fue seleccionado entre otros medios de cultivo, por el óptimo crecimiento que presento la BSR. Se preparar...

  18. Tratamiento quirúrgico sin circulación extracorpórea de la fibrilación auricular aislada para la prevención secundaria de accidentes cerebrovasculares isquémicos agudos

    Directory of Open Access Journals (Sweden)

    Rafael Hernández-Estefanía

    2006-07-01

    Conclusiones: Nuestra experiencia inicial en el tratamiento de la FA aislada mediante ABVP con argón y sin CEC ofrece buenos resultados. Debe documentarse la persistencia del efecto y su eficacia en la reducción de los fenómenos tromboembólicos.

  19. Caracterización fenotípica de cepas invasivas de Neisseria meningitidis aisladas en Cuba durante 20 años

    Directory of Open Access Journals (Sweden)

    Isabel Martínez

    2006-04-01

    Full Text Available Se investigaron los marcadores epidemiológicos (serogrupos, serotipos, subtipos, inmunotipos de 429 cepas invasivas, aisladas en Cuba durante 20 años (1982-2002. Basándonos en el comportamiento de la incidencia de la Enfermedad Meningocócica (EM en el período investigado, las cepas se distribuyeron en dos etapas: epidémica y postepidémica. La epidémica, comprendió 279 cepas aisladas entre 1982-1992 y la ostepidémica, incluyó 150 aislamientos pertenecientes al período comprendido entre 1993-2002. Todas se cultivaron en Agar Mueller Hinton con suero fetal bovino (5% y se incubaron 24-48 horas, 37 0C, en atmósfera húmeda con 5% de C02. La identificación de género, especie y serogrupo, se realizó mediante métodos convencionales; para la caracterización de los sero/subtipos e inmunotipos, se utilizó el ensayo inmunoenzimático (ELISA de células enteras con anticuerpos monoclonales. En ambas etapas predominó el serogrupo B (97,90%: epidémica (96,77% y postepidémica (100%. Sin embargo, el serogrupo C (1,43% y cepas no agrupables (1,8%, sólo se observaron en aislamientos de la etapa epidémica. Los otros marcadores prevalentes fueron: serotipo 4 (86,48%, subtipo P1.19,15 (78,32%, inmunotipo L3,7,9 (90,2% , todos mostraron cifras similares en ambos períodos.Predominó el fenotipo B:4:P1.19,15:L3,7,9 (69,69%, aunque, en la etapa postepidémica (77,34%, el porcentaje fue superior al de la etapa epidémica (65,66% (p<0,05; además, en las cepas de este período, se observó una mayor diversidad de asociaciones fenotípicas. Los resultados obtenidos de esta caracterización fenotípica de las cepas de Neisseria meningitidis aisladas de enfermos aporta datos valiosos al estudio, prevención y control exitoso de la EM en Cuba.

  20. 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.

  1. Estabilidad de almacenamiento de ensilados biológicos a partir de residuos de pescado inoculados con bacterias ácido-lácticas

    OpenAIRE

    Holguín Hernández, Martha Stella; Caicedo Mesa, Luis Alfonso; Veloza Gómez, Luis Carlos

    2010-01-01

    Se elaboraron cuatro muestras por triplicado de ensilados biológicos para alimentación animal a partir de residuos de pescado, utilizando melaza como fuente de carbohidratos para el crecimiento de cuatro cepas de bacterias ácido-lácticas (BAL) aisladas de los mismos, sometidos a un tiempo de incubación de 72 horas y temperatura de 35 °C (±2 °C) para acidificar el producto como método de conservación. A continuación los ensilados se almacenaron durante 180 días a temperatura ambiente para eval...

  2. Evaluación serológica de una proteína recombinante a partir de una cepa aislada del virus de la fiebre amarilla en el Perú: un estudio piloto

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    Carlos Yábar V

    2003-10-01

    Full Text Available Objetivo: Evaluar serológicamente una proteína recombinante de 66 kDa (Er66 de una cepa del virus de la fiebre amarilla aislada en el Perú usando anticuerpos inmunoreactivos. Material y métodos: La proteína Er66 fue expresada in vitro en la bacteria Escherichia coli y enfrentada a títulos de 1/100, 1/50 y 1/25 de anticuerpos monoclonales, y a sueros con anticuerpos IgM e IgG inmunoreactivos contra el virus de la fiebre amarilla mediante ensayos de Western blot (WB. Asimismo, se evaluaron proteínas totales de las cepas de referencia del virus dengue (DEN y fiebre amarilla como controles de antigenicidad. Resultados: La proteína recombinante Er66 presentó antigenicidad contra títulos de 1/50 y 1/25 de anticuerpo monoclonal (MAB8701; sin embargo, no se observó inmunoreactividad en sueros positivos para fiebre amarilla y dengue. Los ensayos con extractos crudos de la cepa de fiebre amarilla Asibi 17D (PTFA revelaron que la antigenicidad de las proteínas virales comprendidas entre 60 y 80 kDa fue afectada negativamente a temperaturas desnaturalizantes de 100°C. En cambio, tratamientos con ß-mercaptoetanol sin calor generó un aumento de la antigenicidad de dichas proteínas. Siguiendo este mismo principio, la proteína Er66 fue sometida a tratamientos desnaturalizantes con ß-mercaptoetanol sin incluir calor y fue enfrentada nuevamente a los sueros reactivos. El resultado final reveló que la proteína Er66 generó inmunoreactividad frente a sueros con altos títulos de anticuerpos IgM e IgG para fiebre amarilla mientras que en otras muestras se observó una débil señal. Conclusiones: Los datos obtenidos en este trabajo demuestran que la Er66 pudo ser reconocida por anticuerpos IgM e IgG específicos para fiebre amarilla presentes en sueros de pacientes infectados. Los datos presentados en este artículo sugieren el uso de proteínas recombinantes como posibles candidatas de valor diagnóstico para la FA.

  3. Rumen bacteria

    International Nuclear Information System (INIS)

    McSweeney, C.S.; Denman, S.E.; Mackie, R.I.

    2005-01-01

    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 10 11 viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (10 4 -10 6 /g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 10 2 -10 4 /g distributed over 5 genera). The occurrence of bacteriophage is well documented (10 7 -10 9 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

  4. Empleo de la ultrafiltración extracorpórea aislada para el tratamiento de la insuficiencia cardiaca descompensada: dificultades técnicas y evolución clínica

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    José Luis Cobo Sánchez

    2013-12-01

    Full Text Available La ultrafiltración extracorpórea aislada se ha revelado como una posible estrategia terapéutica para pacientes con insuficiencia cardíaca descompensada resistente a diuréticos. Nuestro objetivo fue evaluar la evolución clínica a corto-medio plazo de los pacientes sometidos a ultrafiltración extracorpórea aislada y las incidencias técnicas/clínicas. Material y método: Estudio descriptivo transversal prospectivo en pacientes con insuficiencia cardíaca en estadio III-IV de la New York Heart Association resistentes al tratamiento diurético. La ultrafiltración extracorpórea aislada se realizó con el sistema Dedyca®, usando como acceso vascular un catéter venoso central. La tasa de ultrafiltración se iba ajustando en función de la tensión arterial del paciente. Para evaluar la evolución clínica se realizaron controles clínicos y analíticos antes y 1 mes después de las sesiones de ultrafiltración extracorpórea aislada. Para evaluar las complicaciones técnicas/clínicas se revisaron los registros de enfermería. Resultados: Se estudiaros 6 pacientes, que realizaron una media de 2 sesiones, con una duración media de 5 horas y una ultrafiltración media de 2100cc por sesión. Respecto a las complicaciones técnicas, sólo un paciente presentó coagulación parcial delsistema. Ningún paciente presentó efectos adversos durante la ultrafiltración extracorpórea aislada. Conclusiones: Tras la ultrafiltración extracorpórea aislada, aumenta la diuresis con la misma dosis de diurético e incluso con disminución progresiva. Es una técnica sencilla, sin complicaciones técnicas para enfermeras familiarizadas con técnicas de depuración extracorpórea.

  5. Proyecto de instalación eléctrica en baja tensión para una vivienda aislada mediante paneles solares y grupo electrógeno, sita en el término municipal de L'Olleria, Valencia

    OpenAIRE

    APARICI DOMENECH, JOSÉ ENRIQUE

    2015-01-01

    [ES] Cálculo de las necesidades de confort y diseño de las instalaciones para habitar una vivienda aislada, mediante energías renovables. Aparici Domenech, JE. (2015). Proyecto de instalación eléctrica en baja tensión para una vivienda aislada mediante paneles solares y grupo electrógeno, sita en el término municipal de L'Olleria, Valencia. http://hdl.handle.net/10251/54564. TFGM

  6. The biological degradation as an energy option, determination of the effects of the aerobic phase on the subsequent production of biogas in a sanitary landfill; La degradacion biologica como una opcion energetica, determinacion de los efectos de la fase aerobia sobre la subsecuente produccion de biogas en un relleno sanitario

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Juarez, Oscar [Asesoria de Servicios Ambientales del Bajio (ASSB), (Mexico)

    2010-07-01

    The present work deals with the energy evaluation of biological processes as energy source and is based on works concerning laboratory, pilot and field research. The objective of the research is to integrate the effect of the aerobic phase during the process of degradation of organic residues (basically the organic fraction of domestic residues), where the last aim is the biogas production. The usefulness of the results is reflected in the suitable estimation of the filling of a sanitary landfill considering the composition of the residues deposited and the effects that this management will have on the run-up time of the same and the velocity of biogas production. Finally, integrates a reflection on the intrinsic energy implications of the process and of the biogas yielding, which is evaluated as well as energy source. [Spanish] El presente trabajo trata sobre la valoracion energetica de procesos biologicos como fuente de energia y se basa en trabajos de investigacion a nivel de laboratorio, piloto y de campo. El objetivo de la investigacion es integrar el efecto de la fase aerobia durante el proceso de degradacion de residuos organicos (basicamente la fraccion organica de residuos domesticos), donde el fin ultimo es la produccion de biogas. La utilidad de los resultados se refleja en la estimacion adecuada del llenado de un relleno sanitario considerando la composicion de los residuos ahi depositados y los efectos que tendra esta gestion sobre el tiempo de estabilizacion de los mismos y la velocidad de produccion de biogas. Finalmente, se integra una reflexion sobre las implicaciones energeticas intrinsecas al proceso y del rendimiento de biogas, el cual a su vez es valorizado como fuente de energia.

  7. Aspectos pronósticos de la cirugía aislada de sustitución valvular tricuspídea

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    Ana Redondo Palacios

    2018-03-01

    Full Text Available Resumen: Introducción: La cirugía de sustitución valvular tricúspide (SVT aislada es una intervención poco frecuente, con una indicación controvertida, en gran parte debido a su mal pronóstico. Material y métodos: Se analizaron todos los pacientes intervenidos de SVT aislada entre los años 2003 y 2014. Se analizó: a Mortalidad perioperatoria y a largo plazo; y b Aparición de complicaciones relacionadas con las prótesis tricúspides a largo plazo (trombosis y degeneración protésica. Resultados: Durante el periodo de estudio se realizaron 40 intervenciones de SVT aislada. El 82,5% de los pacientes se encontraban en clase funcional iii/iv de la NYHA, y el 70% tenían hipertensión pulmonar al menos moderada (presión sistólica arterial pulmonar > 40 mmHg. La mortalidad perioperatoria fue del 25%, infraestimada por EuroSCORE I (mortalidad estimada del 13,89%. La anemia preoperatoria (OR: 0,52; IC 95%: 0,30-0,89; p = 0,017 se asoció con una mayor mortalidad perioperatoria. La reintervención se asoció con una tendencia a una mayor mortalidad perioperatoria (p = 0,081. La supervivencia tardía, tras 44 meses de seguimiento mediano, fue del 57,50%. Los factores significativamente asociados con una peor supervivencia en el seguimiento fueron: 1 Hipertensión pulmonar severa (OR: 5,77; IC 95%: 1,06-31,26; p = 0,042 y 2 Clase funcional iv (OR: 8,31; IC 95%: 1,48-49,06; p = 0,004. Los pacientes intervenidos en clase funcional iv de la NYHA presentaron una escasa supervivencia a largo plazo (12,5% de supervivencia al año; log rank p = 0,004. Conclusiones: La SVT aislada se asocia con una alta mortalidad, debido a la indicación de la intervención en avanzados estados de cardiopatía.La indicación de cirugía ha de hacerse de manera precoz, antes del deterioro de la función ventricular derecha o de la aparición de hipertensión pulmonar severa. La cirugía en clase funcional NYHA iv supone un escaso beneficio en t

  8. Igualdad de acceso a la telesanidad en zonas rurales y aisladas: propuesta de un marco ético normativo integral de acceso y distribución

    Directory of Open Access Journals (Sweden)

    María Graciela de Ortúzar

    2009-01-01

    Full Text Available Según la Asociación Médica Mundial, el uso de TICs (Tecnologías de la Información y Comunicaciones ¿ TICs- en salud, conocidas también como telesanidad y/o telemedicina, "es el ejercicio de la medicina a distancia, cuyas intervenciones, diagnósticos, decisiones de tratamientos y recomendaciones están bañadas en datos, documentos y otra información transmitida através de telecomunicación". Estas nuevas prácticas en el sistema de salud implican nuevos problemas éticos, legales, sociales, y tecnológicos que afectan los modelos actuales de atención de la salud. En términos generales, se ha priorizado el problema de la confidencialidad en el manejo de la información médica. Sin embargo, uno de los más importantes problemas éticos es justamente la igualdad de oportunidades en el acceso a TIC en salud (prevención, tratamiento, cura o rehabilitación. Por ello, el objetivo del presente trabajo constituye el lineamiento de un marco ético para evaluar el impacto en el acceso a la salud de los programas de telemedicina en zonas rurales y aisladas. En un segundo nivel, se analizará la regulación de uso de TICs en salud, considerando, responsabilidad profesional y social, respeto a la confidencialidad en el uso de la información médica (historias clínicas electrónicas y acceso a base de datos. La metodología utilizada es "equilibrio reflexivo" entre la teoría y la práctica. La hipótesis general que defenderé aquí es la necesidad de un marco ético integral para evaluar y regular el uso de programas de telemedicina en zonas rurales y aisladas, debido a que el impacto en la accesibilidad poblacional constituye el único sistema de salud alternativo para estas regiones.

  9. Evaluación de la actividad fungistática in vitro de bacterias ácido lácticas contra especies de Fusarium causantes de pudrición basal en pitahaya amarilla (Selenicereus megalanthus Haw)

    OpenAIRE

    Valencia Hernández, Leidy J

    2015-01-01

    Fusarium sp. Es uno de los principales hongos fitopatógenos causantes de enfermedades en pitahaya amarilla. Estudios previos han demostrado la capacidad antimicrobiana de bacterias ácido lácticas (BAL) contra patógenos; sin embargo no se ha reportado en la literatura científica actividad fungistática de BAL contra especies de Fusarium causantes de pudrición basal en pitahaya amarilla. En este trabajo se evaluó in vitro la actividad fungistática de una BAL aislada de cultivos de pitahaya amari...

  10. Repercusiones en la salud pública de la resistencia a quinolonas en bacterias de origen animal QUINOLONAS EN BACTERIAS DE ORIGEN ANIMAL

    Directory of Open Access Journals (Sweden)

    José Antonio Orden Gutiérrez

    2001-01-01

    Full Text Available Las fluoroquinolonas son una de las clases de agentes antimicrobianos más útiles empleadas hoy en día en medicina humana y animal debido a su espectro y a sus propiedades fisicoquímicas. El uso de quinolonas en animales es un asunto de especial preocupación porque podría contribuir a la adquisición de resistencia en bacterias transmitidas por alimentos (tales como Salomonella spp., Campylobacter spp. y Escherichia coli y esto, a su vez, podría conducir a una reducción en la eficacia de tales componentes en el tratamiento de infecciones en los seres humanos. Sin embargo, la relación causal entre el uso de fluoroquinolonas en medicina veterinaria y el aislamiento de bacterias resistentes a fluoroquinolonas en humanos no ha sido generalmente probada y, además, el uso de fluoroquinolonas en animales es sólo uno de los muchos factores implicados en la resistencia a estos antimicrobianos. A pesar de ello, la vigilancia de la resistencia a fluoroquinolonas en bacterias aisladas de animales y alimentos y el uso adecuado de estos antimicrobianos en animales deben tener la máxima prioridad.

  11. La dosificación de la intensidad en el desarrollo de la resistencia aerobia de los atletas de Marcha deportiva, categorías 16 -17 años de la ESPA Ormani Arenado de Pinar del Río

    Directory of Open Access Journals (Sweden)

    Ernesto Santana García

    2009-03-01

    Full Text Available La creciente demanda de recursos tecnológicos que presupone el deporte contemporáneo, pone en franca desventaja a los países en vías de desarrollo respecto a los llamados “del primer mundo”, a la vez que compromete a los primeros a redoblar sus esfuerzos intelectuales e investigativos para lograr compensaciones, a partir de la implementación de nuevas alternativas metodológicas accesibles y generalizables. Con el uso de diversas herramientas investigativas se pudo constatar que no se aplica por razones de imposibilidad real, la dosificación y el control de la intensidad para el entrenamiento aerobio a través de las zonas de rendimiento cardiorrespiratorio, pues no existen referencias suficientes sobre la relación entre estas y la velocidad de traslación, por lo cual se precisa de un pulsímetro y este elevaría grandemente el costo del proceso de preparación del deportista de  Marcha  Deportiva, por lo que, nos  planteamos como objetivo de  este trabajo:  proponer  una  alternativa  metodológica  para  contribuir a un  mejor control y dosificación de la intensidad en el desarrollo de la resistencia aerobia en los atletas de esta modalidad, categorías 16 -19 años. Para ello nos hemos auxiliado de herramientas investigativas tales como, el Análisis Síntesis, la inducción deducción, la encuesta y el análisis porcentual, entre otras. Los resultados alcanzados, tuvieron como referencia los criterios de entrenadores y las teorías más actualizadas, a partir de lo cual, se logra una alternativa metodológica que hace posible responder  al objetivo planteado.

  12. Caracterización genotípica y fenotípica de cepas emergentes de Escherichia coli aisladas de niños con diarrea en Bucaramanga y su área metropolitana, Colombia

    Directory of Open Access Journals (Sweden)

    Monica Yurley Arias Guerrero

    2016-06-01

    Full Text Available Introducción: La enfermedad diarreica aguda (EDA sigue siendo uno de los principales problemas en salud pública en países en desarrollo. Dentro de los agentes infecciosos que causan esta enfermedad se encuentran bacterias, virus y parásitos. Los agentes bacterianos ocupan un segundo lugar destacándose Escherichia coli enteropatógenas entre las más importantes. Actualmente, seis cepas con diferentes mecanismos de patogenicidad están asociados a diarrea  E. coli enteropatógena (ECEP, productora de toxina-shiga (ECTS, enterotoxigénica (ECET, enteroinvasiva (ECEI, enteroagregativa (ECEA y adherente difusa (ECAD, cada una con un set específico de genes de virulencia. No obstante, se han reportado brotes de EDA ocasionados por cepas de E. coli diferentes a los patotipos conocidos, denominadas cepas emergentes. Estos brotes han sido reportados en Alemania, Europa y recientemente en Cartagena Colombia, lo que sugiere que en nuestro medio circulan estas cepas. Por lo cual, es necesario caracterizar estas cepas emergentes. Objetivo: Caracterizar genotípicamente y fenotípicamente dos cepas emergentes de E. coli aisladas de muestras diarreicas en niños menores de cinco años en Bucaramanga, Colombia. Materiales y métodos: De un estudio de casos y controles realizado entre Julio del 2013 y diciembre del 2014 en Bucaramanga y su área metropolitana, Colombia a 860 niños menores de 5 años con diarrea (casos y sin diarrea (controles. Se aislaron a partir de coprocultivos cepas de E. coli mediante pruebas bioquímicas. A estas cepas previamente almacenadas a -80°C se les determino mediante PCR multiplex los patotipos de E. coli, los cuales posteriormente fueron confirmados mediante PCR simple. Muestras positivas para dos patotipos u otra característica fueron clasificadas como cepas emergentes. Finalmente, estas cepas se caracterizaron fenotípica y genotípicamente. Para ello, se llevaron a cabo pruebas como secuenciación de genes de

  13. Inhibition of the growth of Ascosphaera apis by Bacillus and Paenibacillus strains isolated from honey Inhibición del crecimiento de Ascosphaera apis mediante cepas de Bacillus y Paenibacillus aisladas de miel

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    F. J. Reynaldi

    2004-03-01

    Full Text Available The fungus Ascosphaera apis, the causative agent of chalkbrood disease in honeybee larvae, occurs throughout the world and is found in many beekeeping areas of Argentina. The potential as biocontrol agents of 249 aerobic spore-forming bacterial antagonists isolated from honey samples was evaluated. Each isolate was screened against A. apis by a central disk test assay. Ten bacterial strains that showed the best antagonistic effect to A. apis were selected for further study and identified as Bacillus cereus (m363, mv86, mv81, mv75, Bacillus circulans (Fr231, m448b, Bacillus megaterium (m435, Bacillus pumilus (m354, Bacillus subtilis (m329, and Paenibacillus alvei (m321. For testing the efficiency of the selected strains, a paired culture test was used with 5 replicates of each combination bacterial antagonist / A. apis strain, and 5 replications for each control on 4 different culture media. The analysis of variance and posterior comparison of means according to LSD method showed that the best antagonists when using YGPSA medium were B. subtilis (m329 and B. megaterium (m435, and in the case of MYPGP medium the most efficient were B. circulans strains Fr 231 and m448b.La cría yesificada es una micosis invasiva ocasionada por el hongo heterotálico Ascosphaera apis que afecta exclusivamente a las larvas de las abejas. La enfermedad tiene difusión mundial y en la Argentina se halla diseminada en todas las áreas donde se realiza apicultura. Se estudió la potencialidad de 249 cepas de bacterias esporuladas aeróbicas aisladas de miel como agentes biocontroladores del hongo mediante un ensayo en disco central en condiciones de laboratorio. Se seleccionaron como mejores antagonistas 10 cepas bacterianas identificadas como Bacillus cereus (m363, mv86, mv81, mv75, Bacillus circulans (Fr231, m448b, Bacillus megaterium (m435, Bacillus pumilus (m354, Bacillus subtilis (m329, y Paenibacillus alvei (m321. Para probar la eficiencia de las cepas

  14. Sensibilidad antimicrobiana y caracterización de cepas de Streptococcus pyogenes aisladas de un brote de escarlatina

    Directory of Open Access Journals (Sweden)

    Pedraza-Avilés Alberto González

    2002-01-01

    Full Text Available Objetivo. Evaluar la actividad in vitro de 13 antibióticos contra 47 Streptococcus pyogenes grupo A (SGA. Determinar la presencia de genes que codifican para exotoxina pirogénica estreptocóccica A (SpeA y serotipos con base en proteína M. Material y métodos. Estudio transversal hecho en el Centro de Salud Dr. José Castro Villagrana sobre un brote de escarlatina en el Colegio Espíritu de América, entre diciembre de 1999 y enero de 2000. El número de niños estudiados fue 137. Se extrajeron porcentajes de sensibilidad. La concentración inhibitoria mínima (CIM se obtuvo por microdilución semiautomatizada. Se utilizó un secuenciador automatizado de DNA para el análisis de variación de secuencias en los genes que codifican para proteína M y SpeA. Resultados. Todas las cepas fueron sensibles a beta-lactámicos y clindamicina; 12.7% fueron resistentes a eritromicina. El serotipo M2 fue el más frecuente, 27 del total. Prácticamente todas las bacterias (96% con el gen SpeA tienen el gen que codifica para el serotipo M2. Conclusiones. Debido a la reciente reaparición de infecciones por SGA se sugiere realizar estudios tanto de sensibilidad a macrólidos y beta-lactámicos, como de epidemiología molecular.

  15. Acción inhibitoria de una cepa de Zymomonas mobilis mobilis aislada de caña de azúcar sobre Xanthomonas citri subsp. citri, agente causal de la cancrosis de los cítricos Inhibition of Xanthomonas citri subsp. citri, causal agent of citrus canker, by a strain of Zymomonas mobilis mobilis isolated from sugarcane

    Directory of Open Access Journals (Sweden)

    María E. Romero

    2008-06-01

    Full Text Available Zymomonas mobilis mobilis (Zm produce factores antimicrobianos que actúan sobre un amplio espectro de microorganismos patógenos para el hombre, animales y plantas. Un problema importante a resolver en los tratamientos con antimicrobianos, es el desarrollo de resistencia a compuestos empleados actualmente, no siendo las bacterias fitopatógenas una excepción. En el presente trabajo se realizaron ensayos de antagonismo con células (pruebas de estrías cruzadas y sobrenadantes concentrados (Sc (por difusión en agar preparados a partir de cultivos de Zm (aislada de jugo de caña de azúcar producido en Tucumán, frente a la bacteria causal de la cancrosis: Xanthomonas citri subsp. citri. Se evaluaron aislamientos de Xcc sensibles (Xc y resistentes (Xcr a compuestos a base de cobre. Los resultados obtenidos mostraron que la bacteria testigo fue inhibida totalmente por las células de Zm, ejerciendo un efecto bactericida. En los ensayos de difusión en el agar se observó que tanto Xc, como Xcr fueron sensibles al Sc de Zm. Se sabe, por estudios anteriores, que los metabolitos de Zymomonas tienen un efecto deletéreo en la membrana celular de E. coli AB1133, inhibiéndose la respiración de la bacteria inmediatamente de agregado Sc (60 UA. En el presente trabajo se observó el mismo efecto, inhibición total de la respiración en Xc, luego del agregado del Sc (60 UA. Por lo observado, se deduce que el blanco de acción de los metabolitos antimicrobianos de Sc en Xc, sería el mismo que el de E. coli AB1133. Con los resultados obtenidos se considera de interés encarar el estudio de los compuestos de Zm para ser empleados en el control de enfermedades que afectan los cultivos de valor económico de la región, como es el caso de la cancrosis, como así también profundizar acerca de la acción de dichos metabolitos en la membrana de Xanthomonas citri subsp. citri.Zymomonas mobilis mobilis (Zm produces antimicrobial factors, which have an effect on

  16. Extracción optimizada y purificación parcial de invertasa aislada de S. Cerevisiae en puré de durazno

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    Marcela Vega Ferreira

    2018-03-01

    Full Text Available Resumen La extracción fue realizada a través de un proceso de autolisis, donde las enzimas degradan las estructuras celulares y liberan el contenido citoplasmático al medio extracelular. El proceso de autolisis fue realizado en shaker con diferentes velocidades de agitación (50 - 350 rpm y concentraciones de bicarbonato de sodio (50 -350 mM NaHCO3 a 40 °C por 24 horas, usando un diseño experimental compuesto central adaptado para dos variables y cinco niveles, así como una metodología de superficie de respuest a (MSR y análisis canónico para definir las condiciones óptimas de extracción de invertasa de S. cerevisiae aislada de puré de durazno (ISc. En la condición optima de extracción, se estudió el efecto de la liofilización y purificación en la actividad de la invertasa, usando el método colorimétrico del ácido 3,5-dinitrosalicílico (DNS a 490 nm para acompañar su actividad expresada en unidades. Una unidad (U es definida como 1 mg glucosa.min-1. El valor de proteínas fue cuantificado por el método Lowry y la invertasa de levadura comercial (ILC como testigo. La influencia de la concentración de NaHCO3 y de la velocidad de agitación en la extracción de la enzima invertasa indicó efecto lineal, cuadrático e interactivo. El modelo de forma polinómica de segundo orden explicó el fenómeno de extracción de la invertasa con un R2 de 0,80, y con actividad significativamente dependiente de ambas variables. La máxima extracción fue observada en el punto central experimental (200 mM NaHCO3 y 200 rpm con una actividad de 14,7 U.mg-1. El punto estacionario es un punto de máxima extracción, el cual difiere en menos de 10% del punto central experimental. De acuerdo a estas características, las óptimas condiciones para extracción de la invertasa de S. cerevisiae aislada de puré de durazno son 200 mM NaHCO3 como agente de autolisis, 200 rpm de agitación orbital a 40oC durante 24 horas y usando una biomasa de

  17. Estudio de una red aislada de distribución de pequeña potencia y gran penetración eólica con la herramienta PSS/E

    OpenAIRE

    Merino Fernández, Julia

    2010-01-01

    El objeto de este proyecto es realizar un análisis de estabilidad ante contingencias en una red aislada de pequeña potencia con alto grado de penetración eólica mediante la herramienta PSS/E con el fin de aportar conocimiento para, posteriormente, definir la forma de operación más adecuada de dicho sistema atendiendo a su eficacia y fiabilidad. La red considerada para el estudio es la de la isla de El Hierro, en el archipiélago de Canarias, donde se tiene previsto abastecer exclusivamen...

  18. Sensibilidad antibiótica de cepas de Haemophilus spp aisladas de pacientes pediátricos en un hospi- tal general entre los años 2003 -2006.

    OpenAIRE

    Alarco Castro, Raúl Rodrigo; Cavero Chávez, Vanessa Yohana; Hernández Díaz, Herminio Renán; Tapia Egoávil, Elena Zoraida

    2012-01-01

    Objetivo: Determinar la sensibilidad antibiótica de cepas de Haemophilus spp aisladas de pacientes pediátricos en un hospital general entre los años 2003 y 2006. Materiales y métodos: Estudio descriptivo retrospectivo en el que se incluyeron cultivos positivos de Haemophilus spp. Se revisaron las historias clínicas de los pacientes de los cuales provenían los cultivos. Resultados: Se encontraron 37 cultivos positivos para Haemophilus spp, entre los cuales se encontró mayor sensibilidad a levo...

  19. Estudio del sistema regulador formado por la serotonina y sus receptores en las células troncales MSC aisladas de médula ósea humana. Adipogénesis.

    OpenAIRE

    González Méndez, Laura

    2014-01-01

    Tesis doctoral inédita, leída en Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 21/03/2014 En los últimos años se ha identificado a la serotonina como un regulador crítico de la masa ósea, regulando tanto directa como indirectamente la actividad de las células responsables del proceso de remodelación ósea, osteoclastos y osteoblastos. El presente trabajo muestra que las MSCs aisladas de la médula ósea humana, células precursoras ...

  20. 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 ...

  1. 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.

  2. Portadores de Neisseria meningitidis, caracterización de las cepas aisladas y respuesta inmune basal a VA-MENGOC-BC

    Directory of Open Access Journals (Sweden)

    María J. Valdés

    2008-08-01

    Full Text Available Con el propósito de conocer la prevalencia de portadores de Neisseria meningitidis en un grupo de adolescentes, los marcadores epidemiológicos de las cepas aisladas, así como los factores de riesgo asociados con el estado de portador y la respuesta inmune basal a VA-MENGOC-BC , se realizó un estudio transversal descriptivo de portadores en 189 estudiantes de 12-19 años de un politécnico de Ciego de Ávila, siguiendo las Normas Bioéticas establecidas. A los estudiantes se les realizó un exudado faríngeo y una extracción de sangre para la obtención de suero, así como una encuesta relacionada con aspectos de la investigación. La identificación de N. meningitidis se hizo por el sistema API NH (bioMérieux. Los serosubtipos e inmunotipos se clasificaron por ELISA de células enteras con anticuerpos monoclonales y la respuesta inmune basal se detectó por el Ensayo Bactericida del Suero. Se determinó la susceptibilidad antimicrobiana de las cepas frente a la penicilina, cloranfenicol, rifampicina, sulfadiacina sódica, ceftriaxona y ciprofloxacina. La prevalencia de portadores de N. meningitidis fue del 17%. Predominaron las cepas no agrupables (84,7%, seguidas por los serogrupos B (12,5% y Z (3,1%, destacándose la ausencia del C. Prevaleció el fenotipo NA:NT:P1.NST:L3,7,9 (12,5%, las cepas resistentes a la sulfadiacina (78,2% y sensibles a penicilina (81,3%, aunque el 18,7% mostró sensibilidad intermedia a este fármaco. Al resto de los antimicrobianos todas fueron sensibles. Se constató una respuesta inmune de memoria a la vacuna antimeningocócica (VAMENGOC-BC®, 12 años después de su aplicación, con títulos bactericidas anti C y B de 25 y 42%, respectivamente, resultados que pudieran estar influenciados por la inmunización sistemática que se realiza en Cuba con esta vacuna desde 1991.

  3. Analisis tecnico, socioeconomico y ambiental de la electrificación con energía solar fotovoltaica aislada para vivienda rural en Hato Corozal, Casanare, Colombia

    Directory of Open Access Journals (Sweden)

    Edwin Blasnilo Rúa Ramírez

    2017-06-01

    Full Text Available La electrificación con energía solar fotovoltaica aislada es la opción más viable para vivienda rural, en especial si se encuentra muy distante del sistema nacional interconectado. Hato Corozal, Casanare, Colombia, es un municipio estructurado en su área rural por fincas muy alejadas entre sí. Su mayor inconveniente de desarrollo social y económico es la falta de electricidad como servicio de primera necesidad.  La gobernación de Casanare a través del fondo nacional de regalías aprobó la instalación de 206 sistemas solares fotovoltaicos (SFV a las familias más alejadas y más vulnerables del municipio. El objetivo principal de esta investigación fue realizar una evaluación socio-económica de las familias de la zona rural del municipio, beneficiadas con la instalación de estos sistemas SFV. Además, se realizó un análisis técnico de simulación de la operación del SFV dimensionado con 2 días sin sol y luego 12 días con sol, también se hizo una simulación de la operación del SFV dimensionado con 14 días con sol. Esta investigación se abordó desde el enfoque metodológico descriptivo y de investigación aplicada de campo que incluyó visita a las viviendas, aplicación, análisis de instrumentos y registro fotográfico.  Los resultados presentan gran incidencia desde un enfoque social, económico y ambiental que puede llegar a ser implementado en otras áreas rurales del país como ejemplo de uso de tecnologías limpias en favor del desarrollo rural sostenible.

  4. Identificación y caracterización de especies de Neosartorya aisladas de frutillas (Fragaria spp. frescas y tratadas térmicamente

    Directory of Open Access Journals (Sweden)

    Laura Frisón

    2012-12-01

    Full Text Available El género Aspergillus es uno de los géneros fúngicos más estudiados y de gran impacto a nivel industrial. La sección Fumigati incluye unas pocas especies anamorfas del género Aspergillus. Las especies que son teleomorfas se encuentran dentro del género Neosartorya. Este es un moho resistente al calor que causan problemas en las industrias alimentarias o enfermedades en los seres humanos. Sus ascosporas han sido aisladas a partir de frutas, pulpas y jugos, ya que pueden sobrevivir a los tratamientos de térmicos industriales pudiendo aparecer la contaminación post-pasteurización. El objetivo fue caracterizar aislados de Neosartorya de frutillas frescas recién cosechadas y tratadas térmicamente, analizando la ornamentación de las ascosporas, toxicidad y resistencia térmica. Se aislaron las colonias, y se identificaron macro y microscópicamente siguiendo la metodología de Pitt y Hocking (2009, de 60 muestras. Se caracterizaron las ascosporas por microscopía electrónica de barrido. Se determinó la capacidad toxicogénica de los extractos por cromatografía líquida de alta eficiencia. Se evaluó la resistencia térmica a diferentes temperaturas. Se aislaron 18 cepas de Neosartorya de frutillas recién cosechadas, y otros mohos termorresistentes como Arthrinium phaeospermum, Byssochlamys nivea y Talaromyces macrosporus. En las frutillas tratadas térmicamente no se aislaron mohos termorresistentes. Trece aislados mostraron ascosporascoincidentes con N. fischeri, el resto con N. spinosa. Los aislados de N. fischeri produjeron fumitremorgina A y B y verruculógeno en arroz, pero no lo hicieron en frutillas frescas. Los parámetros de resistencia térmica fueron: D80 ºC: 20 - 22 minutos, D85 ºC: 9 - 11 minutos, D90 ºC: 2 - 3 minutos y z: 10 - 11 ºC para N. fischeri y D80 ºC: > 120 minutos, D85 ºC: 11 - 94 minutos, D90 ºC: 3 - 15 minutos y z: 6 - 9 ºC para N. spinosa. Es indispensable aplicar buenas prácticas agrícolas y

  5. Identificación y caracterización de especies de Neosartorya aisladas de frutillas (Fragaria spp. frescas y tratadas térmicamente

    Directory of Open Access Journals (Sweden)

    Laura Frisón

    2012-01-01

    Full Text Available El género Aspergillus es uno de los géneros fúngicos más estudiados y de gran impacto a nivel industrial. La sección Fumigati incluye unas pocas especies anamorfas del género Aspergillus. Las especies que son teleomorfas se encuentran dentro del género Neosartorya. Este es un moho resistente al calor que causan problemas en las industrias alimentarias o enfermedades en los seres humanos. Sus ascosporas han sido aisladas a partir de frutas, pulpas y jugos, ya que pueden sobrevivir a los tratamientos de térmicos industriales pudiendo aparecer la contaminación post-pasteurización. El objetivo fue caracterizar aislados de Neosartorya de frutillas frescas recién cosechadas y tratadas térmicamente, analizando la ornamentación de las ascosporas, toxicidad y resistencia térmica. Se aislaron las colonias, y se identificaron macro y microscópicamente siguiendo la metodología de Pitt y Hocking (2009, de 60 muestras. Se caracterizaron las ascosporas por microscopía electrónica de barrido. Se determinó la capacidad toxicogénica de los extractos por cromatografía líquida de alta eficiencia. Se evaluó la resistencia térmica a diferentes temperaturas. Se aislaron 18 cepas de Neosartorya de frutillas recién cosechadas, y otros mohos termorresistentes como Arthrinium phaeospermum, Byssochlamys nivea y Talaromyces macrosporus. En las frutillas tratadas térmicamente no se aislaron mohos termorresistentes. Trece aislados mostraron ascosporas coincidentes con N. fischeri, el resto con N. spinosa. Los aislados de N. fischeri produjeron fumitremorgina A y B y verruculógeno en arroz, pero no lo hicieron en frutillas frescas. Los parámetros de resistencia térmica fueron: D80 ºC: 20 - 22 minutos, D85 ºC: 9 - 11 minutos, D90 ºC: 2 - 3 minutos y z: 10 - 11 ºC para N. fischeri y D80 ºC: > 120 minutos, D85 ºC: 11 - 94 minutos, D90 ºC: 3 - 15 minutos y z: 6 - 9 ºC para N. spinosa. Es indispensable aplicar buenas prácticas agrícolas y

  6. La capacidad de trabajo funcional de las practicantes de Gimnasia Aerobia de Salón en correspondencia con las edades de 18 a 50 años de las escuelas comunitarias del municipio de Pinar del Río

    Directory of Open Access Journals (Sweden)

    Luis Alberto Mojena Rodríguez

    2009-06-01

    Full Text Available Con nuestro trabajo pretendemos brindar un valioso aporte para resolver una de las principales problemáticas que afrontan hoy en día los docentes que imparten  el  programa  de  gimnasia  aerobia  de  salón  ya  que  la  idea  es establecer rangos que nos permita evaluar de B, R y M la capacidad física de resistencia cardiovascular, contribuyendo a que este su principal objetivo se desarrolle sobre bases mas científicas , mediante la aplicación del test de Cooper a practicantes entrenados en las edades comprendidas entre 18 y 50 años  del  sexo  femenino, teniendo  en  cuenta  como  principal  medidor  el consumo máximo de oxigeno para evaluar dicha prueba, que la aplicaremos en tres momentos con dos meses de tiempo de aplicación entre una medición y otra que nos brindara en que por ciento debe mejorar su rendimiento o incrementar la mejoría en esta capacidad entre cada prueba que seria el principal aporte de nuestra investigación premisa la resistencia se puede definir como la capacidad psíquica y física que posee un deportista para resistir la fatiga (Weineck 1992, entendiéndose como fatiga la disminución transitoria de la capacidad de rendimiento. Es la capacidad de realizar un esfuerzo de mayor o menor intensidad, durante el mayor tiempo posible. La capacidad de oposición a la fatiga. Es la lucha para la mejora de la capacidad de absorción de O, ya que cuando se incrementa la intensidad de los esfuerzos, mayor es la necesidad de un aporte de oxígeno. Desde el punto de vista bioquímico,  la resistencia se determina por la relación entre la cantidad de las reservas energéticas dispuestas para su utilización y la velocidad de consumo de la energía durante la práctica deportiva (Menshikov y Volkov 1990. La resistencia tiene como sustrato morfo-funcional  al aparato cardiocirculatorio y respiratorio.  El aparato cardiovascular controla la cantidad de sangre que el corazón bombea y la circulaci

  7. Distribución Diferencial de Bacterias con Potencial Biocontrolador de Spongospora subterranea en Plantas de Papa (Solanum tuberosum cv. Diacol Capiro Differential Distrubution of Candidadate Biocontrol Bacteria against Spongospora subterranea in Potato Plants (Solanum tuberosum cv. Diacol Capiro

    Directory of Open Access Journals (Sweden)

    Juliana Soler Arango

    2012-06-01

    Full Text Available Resumen. La búsqueda de microorganismos promisorios para biocontrol de patógenos de plantas en el suelo con frecuencia se ha orientado a la detección de productores de hormonas y enzimas líticas, condiciones asociadas a su capacidad para promover crecimiento vegetal. Sin embargo, el suelo es altamente variable en escalas pequeñas y se conoce poco sobre la distribución espacial de microorganismos que expresan esas funciones. Este estudio determinó la capacidad de producción de indoles totales y quitinasas en bacterias cultivables aisladas del interior de la raíz, la rizósfera, la superficie de los tubérculos o suelo de un cultivo de papa (Solanum tuberosum variedad Diacol Capiro. Las muestras se obtuvieron en un campo comercial en el municipio de la Unión en el departamento de Antioquia, Colombia, en plantas que presentaban síntomas de infección por Spongospora subterranea. Se encontró una producción diferencial de indoles o quitinasas según el sitio de aislamiento de las bacterias. No se encontró una alta producción de ambas actividades en un sólo aislamiento, la mayor producción de indoles totales y quitinasas se encontró en bacterias aisladas a partir de raíz y rizósfera, comparada con las aisladas de tubérculos y suelo. Estos resultados sugieren que en el suelo no es aleatoria la distribución de funciones deseables en controladores biológicos. Con estos resultados es posible orientar su búsqueda para optimizar el uso de recursos y el desarrollo de nuevos bioproductos.Abstract. Searching for promising microorganisms to biocontrol soil-borne plant pathogens has been often focused on producers of hormone and lytic enzymes, since these traits are linked to plant growth promotion. However, the environment from inner roots to bulk soil is quite variable, and little is known about the spatial distribution of microorganisms expressing these desirable traits. Using potato plants (Solanum tuberosum var. Diacol Capiro from a

  8. Burkholderia tropica una bacteria con gran potencial parasu uso en la agricultura

    Directory of Open Access Journals (Sweden)

    Hernando José Bolívar-Anillo

    2016-01-01

    Full Text Available El género Burkholderia con más de 90 especies reportadas hasta la fecha, se encuentra dividido en dos grupos mayores filogenéticamente distantes. El primer grupo se encuentra constituido por especies patógenas donde destacan los patógenos oportunistas referidos como el complejo Burkholderia cepacia (Bcc;el otro grupo está conformado por especies no patógenas con habilidades para la promoción del crecimiento vegetal y la rizoremediación. Burkholderia tropica es unabacteria con capacidad de fijar nitrógeno; aislada de la rizósfera, rizoplano, tallo y la raíz de plantas de maíz y caña de azúcar. Además de su capacidad diazotrofa, B. tropica presenta características que permiten catalogarla como una bacteria promotora del crecimiento vegetal, por su capacidad de producir sideróforos, solubilizar fosfatos, producir exo-heteropolisacáridos, además de utilizarse como biocontrol para algunos fitoparásitos, lo que la convierte en una bacteria prometedora para su aplicación en el sector agrícola.

  9. 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.

  10. Microbiological study of naturally fermented Algerian green olives: isolation and identification of lactic acid bacteria and yeasts along with the effects of brine solutions obtained at the end of olive fermentation on Lactobacillus plantarum...

    Directory of Open Access Journals (Sweden)

    Nour-Eddine, Karam

    2006-09-01

    Full Text Available The microflora of naturally fermented green olives produced in Western Algeria was studied over 15, 60 and 90 day fermentation periods. Different microorganisms (aerobic bacteria, coliforms, staphylococci, lactic acid bacteria, lactobacilli, enterococci, yeasts, psychrotrophs and lipolytic bacteria were recorded at 15 and 60 days of fermentation. After 90 days (pH 4.40 of fermentation, the lactic acid bacteria population became dominant and persisted together with yeasts throughout the fermentation period. The lactic acid bacteria isolated (343 isolates were identified as L. casei, L. rhamnosus, L. paracasei, L. plantarum, L. lactis subsp. lactis, E. faecalis, E. faecium and E. durans. The dominant species was L. plantarum. Yeasts were isolated from all samples (32 isolates and were identified as Saccharomyces cerevisiae or Candida parapsilosis. Also, in this study we reported that brine solutions obtained at the end of olive fermentation were able to stimulate the growth of several L. plantarum strainsLa microflora de las aceitunas verdes fermentadas naturalmente elaboradas en Argelia Occidental fue estudiada en períodos de fermentación de 15, 60 y 90 días. Diferentes microorganismos (bacterias aeróbicas, coliformes, estafilococos, bacterias del ácido láctico, lactobacilos, enterococos, levaduras, psicotrofos y bacterias lipolíticas fueron detectados a los 15 y 60 días de fermentación. Después de 90 días de fermentación (pH 4.40, la población de bacterias lácticas se hizo dominante y persistió junto con las levaduras a lo largo de todo el proceso. Las bacterias lácticas aisladas (343 fueron identificadas como L. casei, L. rhamnosus, L. paracasei, L. plantarum, L. lactis subsp. lactis, E. faecalis, E. faecium y E. durans. La especie dominante fue L. plantarum. Las levaduras aisladas (32 de todas las muestras fueron identificadas como Saccharomyces cerevisiae o Candida parapsilosis. También se recoge en este estudio que las

  11. How honey kills bacteria

    NARCIS (Netherlands)

    Kwakman, Paulus H. S.; te Velde, Anje A.; de Boer, Leonie; Speijer, Dave; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria

  12. Chemotactic responses to gas oil of Halomonas spp. strains isolated from saline environments in Argentina Respuesta quimiotáctica hacia gas oil de cepas de Halomonas spp. aisladas de ambientes salinos de Argentina

    Directory of Open Access Journals (Sweden)

    Sebastián D´Ippólito

    2011-06-01

    Full Text Available In this study, two halophilic bacterial strains isolated from saline habitats in Argentina grew in the presence of gas oil. They were identified as Halomonas spp. and Nesterenkonia sp. by 16S ribosomal RNA sequencing. Chemotaxis towards gas oil was observed in Halomonas spp. by using swimming assays.En el presente trabajo se aislaron dos cepas bacterianas halofílicas a partir de muestras obtenidas en ambientes salinos de Argentina, que crecieron en presencia de gasoil como única fuente de carbono. Las cepas aisladas se identificaron como Halomonas spp. y Nesterenkonia sp. mediante secuenciación del gen del ARN ribosomal 16S. En ensayos de swimming, las cepas del genero Halomonas spp. mostraron una respuesta quimiotáctica hacia el gas oil.

  13. Identificación, biotipificación y caracterización de cepas de Pasteurella multocida aisladas en la Argentina Identification, biotypification and characterization of Pasteurella multocida strains isolated in Argentina

    Directory of Open Access Journals (Sweden)

    G. A. Leotta

    2006-09-01

    Full Text Available Treinta cepas de Pasteurella multocida aisladas en la Argentina a partir de muestras de origen humano y animal fueron identificadas, biotipificadas y caracterizadas. Veintidós de ellas (73% correspondieron a P. multocida subsp. multocida; cinco (17% a P. multocida subsp. gallicida y tres (10% a P. multocida subsp. septica. Todas las cepas fueron agrupadas en 8 biotipos; el 70% presentó el tipo capsular A. Los serotipos somáticos más frecuentes fueron el 1 (n:11 y el 3 (n:9. Las cepas de origen porcino fueron resistentes a tiamulina, estreptomicina y tetraciclina. La caracterización de las cepas de P. multocida aisladas en la Argentina es el primer paso para concretar futuros estudios destinados a la prevención y al tratamiento de la pasteurelosis en medicina humana y veterinaria.Thirty Pasteurella multocida strains isolated in Argentina from human and animal samples were identified, biotypified and characterized. Twenty-two (73% strains were identified as P. multocida subsp. multocida, 5 (17% as P. multocida subsp. gallicida, and 3 (10% as P. multocida subsp. septica. All strains were grouped in 8 biotypes, and 70% of the strains presented capsular type A. The most frequent somatic serotypes were 1 (n:11 and 3 (n:9. P. multocida strains from swine source were resistant to tiamulin, streptomycin and tetracycline. Characterization of P. multocida strains isolated in Argentina is the first step to conduct future studies intended for the prevention and treatment of pasteurellosis in human and veterinary medicine.

  14. Antibiotics from predatory bacteria

    Directory of Open Access Journals (Sweden)

    Juliane Korp

    2016-03-01

    Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

  15. Resistencia inducida a la enfermedad del añublo de la panícula del arroz inoculando bacterias endofíticas

    Directory of Open Access Journals (Sweden)

    Manuel José Peláez Pelaez

    2017-09-01

    Full Text Available Se evaluó el efecto antagónico de las bacterias endófitas aisladas de porciones de hojas, tallos y raíces de plantas de arroz completamente sanas, contra la bacteria patogénica Burkholderia glumae (Kurita & Tabei, 1967, agente causal   de la enfermedad del añublo bacterial de la panícula. Se obtuvieron 24 aislamientos en total de bacterias endófitas que fueron evaluadas mediante la técnica de enfrentamiento de cultivos duales, en condiciones de laboratorio, posteriormente se realizaron las inoculaciones de la solución bacteriana en condiciones de campo para evaluar el efecto antagónico. Los resultados obtenidos indican que sólo dos cepas bacterianas presentaron actividad antagónica contra B. glumae las cuales fueron identificadas mediante caracterización bioquímica, de los bioensayos realizados a nivel de laboratorio y en campo. Por tanto, hubo una mejor expresión de las bacterias antagónicas bajo condiciones controladas en el laboratorio comparado con los ensayos realizados en campo

  16. Extracellular communication in bacteria

    DEFF Research Database (Denmark)

    Chhabra, S.R.; Philipp, B.; Eberl, L.

    2005-01-01

    molecules, in different Gram-positive and Gram-negative bacteria they control pathogenicity, secondary metabolite production, biofilm differentiation, DNA transfer and bioluminescence. The development of biosensors for the detection of these signal molecules has greatly facilitated their subsequent chemical...

  17. Do Bacteria Age?

    Indian Academy of Sciences (India)

    Bacteria are thought to be examples of organisms that do not age. They divide by .... carry genetic material to the next generation through the process of reproduction; they are also .... molecules, and modified proteins. This report revealed that ...

  18. Social Behaviour in Bacteria

    Indian Academy of Sciences (India)

    Administrator

    the recipient. • Social behaviours can be categorized according to the fitness ... is actually the flagella of symbiotic spirochete bacteria that helps it to swim around .... Normal population. Responsive switching. (Environmental stress). Stochastic.

  19. [Darwin and bacteria].

    Science.gov (United States)

    Ledermann D, Walter

    2009-02-01

    As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  20. Lipopolysaccharides in diazotrophic bacteria

    OpenAIRE

    Serrato, Rodrigo V.

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are...

  1. Lipopolysaccharides in diazotrophic bacteria.

    Science.gov (United States)

    Serrato, Rodrigo V

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

  2. CARACTERIZACIÓN PRELIMINAR DE COMPUESTOS ANTILISTERIALES PRODUCIDOS POR BACTERIAS ÁCIDO LÁCTICAS NATIVAS

    Directory of Open Access Journals (Sweden)

    Blanca Botina A

    2008-12-01

    Full Text Available Objetivo. Caracterizar los metabolitos producidos por bacterias ácido lácticas nativas con capacidad antilisterial. Materiales y métodos. Se analizaron 42 muestras tomadas de alimentos y equipos procesadores de alimentos, de donde se aislaron bacterias ácido lácticas, las cuales se identificaron por medio de pruebas bioquímicas. Se evaluó la actividad antagónica de las cepas aisladas frente a 17 cepas de L. monocytogenes pertenecientes a los serotipos 4b, 4e, y 3b utilizando la técnica de la gota y doble capa. Se obtuvieron extractos crudos para la caracterización de los metabolitos inhibitorios del crecimiento de las cepas de L. monocytogenes, los cuales fueron tratados con catalasa, ácido clorhídrico, proteinasa K y temperaturas de 95ºC y 121ºC. El peso molecular de las proteínas se aproximó utilizando la técnica de electroforesis SDS-PAGE y bioensayos. Resultados. De un total de 250 aislamientos se lograron identificar 75 cepas de bacterias ácido lácticas. La evaluación de la actividad antagónica indicó que los metabolitos inhibitorios producidos por las bacterias ácido lácticas no actuaban de igual manera frente a las diferentes cepas de L. monocytogenes. Sin embargo, se encontró que tres de los aislamientos nativos identificados como Lactobacillus spp., Leuconostoc spp. y Enterococcus spp. presentaban una mejor actividad antilisterial debido a que sintetizan proteínas o metabolitos de peso molecular menor a 7600 Da. Conclusiones. En los alimentos distribuidos en Colombia existen cepas de bacterias ácido lácticas con potencial bioprotector.

  3. Análisis de predictores independientes del flujo del bypass coronario en pacientes intervenidos de revascularización miocárdica aislada

    Directory of Open Access Journals (Sweden)

    Stefano Urso

    2017-11-01

    Full Text Available Resumen: Introducción y objetivo: El medidor de flujo permite conocer 2 parámetros: el flujo medio del bypass coronario y el índice de pulsatilidad. Estos 2 parámetros, cuando están alterados, pueden indicar una estenosis de la anastomosis del bypass distal. Factores distintos de la suficiencia de la anastomosis, como la calidad de lecho coronario, pueden condicionar el flujo del bypass y dificultar su interpretación. El objetivo de nuestro estudio es analizar los predictores independientes del flujo de los bypass aorto-coronarios. Métodos: Recogimos de forma retrospectiva una serie consecutiva de 90 pacientes intervenidos de revascularización miocárdica aislada por el mismo cirujano desde enero del 2014 hasta agosto del 2016. A partir de esta serie, elaboramos una base de datos electrónica donde cada registro correspondía a un injerto. Construimos, por lo tanto, una base de datos de 185 injertos. De estos, 8 injertos no fueron analizados por no haberse medido el flujo correctamente. Por los tanto, los valores de flujo y de índice de pulsatilidad de 177 injertos fueron utilizados para nuestro análisis estadístico. Resultados: El análisis de regresión lineal múltiple detectó 2 predictores independientes del flujo de los bypasses: injerto de vena safena secuencial (valor r parcial: 0,32; p < 0,0001 e injerto arterial (valor r parcial: –0,23; p 0,0021. Por lo tanto, nuestro modelo objetivó una correlación directa entre la utilización de injerto de safena con técnica secuencial y flujo del bypass, y una correlación inversa entre la utilización de injerto arterial y flujo del bypass. Conclusiones: Los predictores del flujo de los bypasses aorto-coronarios son la utilización de un injerto arterial (coeficiente negativo y la utilización de un injerto venoso secuencial (coeficiente positivo. Nuestro modelo estadístico no ha identificado como predictor el SYNTAX score

  4. The fecal bacteria

    Science.gov (United States)

    Sadowsky, Michael J.; Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  5. Linear Alkylbenzene Sulfonate tolerance in bacteria isolated from sediment of tropical water bodies polluted with detergents

    Directory of Open Access Journals (Sweden)

    I.T Kehinde

    2008-12-01

    ambiente acuático. El tensoactivador persiste en algunos arroyos y ríos de Nigeria, en parte es absorbido por materiales en suspensión y termina entre los sedimentos de los cuerpos de agua receptores. En este estudio, bacterias aisladas de los sedimentos de algunos arroyos tropicales que reciben efluentes contaminados con detergentes, fueron analizadas para determinar su tolerancia a los LAS, utilizando la técnica de dilusión del medio. Las bacterias se consideraron tolerantes a los LAS cuando continuaron creciendo aún en presencia del tensoactivador. En los sedimentos también se determinó acidez (pH, concentración de tensoactivador, poblaciones de bacterias heterotróficas y de bacterias tolerantes a los LAS. Se encontró una relación directa (r= 0.9124 entre condiciones alcalinas (pH= 8.2-12.0 y concentraciones altas de tensoactivador (45-132 mg/g en los sedimentos. Además, los sedimentos mostraron albergar a una población grande y variada de bacterias; las poblaciones de bacterias heterotróficas (vHB: 2.9×10(5 -1.2×10(7 cfu/g y bacterias tolerantes a los LAS (LTB: 1.5×10(4 -1.2×10(6 cfu/g, mostraron una relación directa (r= 0.9500. Por otra parte, una relación inversa se encontró entre cada una de ellas y la concentración de tensoactivador en los sedimentos, r vHB/ LAS = -0.9303 y rLTB/ LAS = -0.9143 respectivamente. Doce especies de bacterias fueron aisladas de los sedimentos: Alcaligenes odorans, Bacillus subtilis, Burkholderia cepacia, Citrobacter freundii, Citrobacter diversus, Escherichia coli, Micrococcus luteus, Micrococcus albus, Pseudomonas putida, Pseudomonas stutzeri, Staphylococcus aureus y Streptococcus faecalis. La mayoría de esas especies muestra adaptaciones al tensoactividor, siempre que éste se encuentre en concentraciones entre 0.03 y 1.0% (w/v. Los sedimentos pueden servir como una fuente de organismos que pueden ser utilizados en el bio-tratamiento de desechos que contengan LAS.

  6. Mycorrhiza helper bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Deveau, Aurelie [French National Insitute for Agricultural Research (INRA); Labbe, Jessy [ORNL

    2016-10-01

    This chapter focuses on the Mycorrhiza Helper Bacteria (MHB), a generic name given to bacteria which stimulate the formation of mycorrhizal symbiosis. By extension, some bacterial strains that positively impact the functioning of mycorrhizal symbiosis are also called MHB. These bacteria have applicative interests, as they indirectly improve the health and growth of tree seedlings. MHB are not restricted to a specific type of ecosystem, but are rather generalist in the way that they associate with both herbaceous and woody mycorrhizal plants from boreal, temperate, arid and tropical ecosystems. However, understanding the molecular mechanisms and their specificities will help us to know more about the ecology of the MHB. The process of acquisition varies between fungal species; while ectomycorrhizal fungi most probably recurrently acquire them from the environment, the association between bacterial endosymbionts and Glomeromycota probably dates back to very ancient times, and has since been vertically transmitted.

  7. Prueba de sensibilidad antimicrobiana de cepas de salmonella grupo D (móviles e inmóviles) aisladas de ponedoras comerciales en Colombia

    OpenAIRE

    J. Mantilla; M. Pulido; J. Jaime

    2010-01-01

    Las infecciones originadas por bacterias del género Salmonella son una de las principales causas de pérdidas económicas en la industria avícola, se caracterizan generalmente por la presentación de cuadros diarreicos y septicémicos que llevan a las aves a una marcada disminución en la producción y a la muerte. En Colombia, debido al efecto negativo que produce Salmonella spp. en las aves, y con el objetivo de poder controlar la enfermedad, se utiliza una gran variedad de productos antimicrobia...

  8. Prueba de sensibilidad antimicrobiana de cepas de salmonella grupo d (móviles e inmóviles) aisladas de ponedoras comerciales en colombia

    OpenAIRE

    Mantilla, J.; Pulido, M.; Jaime, J.

    2010-01-01

    Las infecciones originadas por bacterias del género Salmonella son una de las principales causas de pérdidas económicas en la industria avícola, se caracterizan generalmente por la presentación de cuadros diarreicos y septicémicos que llevan a las aves a una marcada disminución en la producción y a la muerte. En Colombia, debido al efecto negativo que produce Salmonella spp. en las aves, y con el objetivo de poder controlar la enfermedad, se utiliza una gran variedad de product...

  9. Evaluación de la susceptibilidad antimicrobiana de cepas de Salmonella spp. aisladas del beneficio porcino en Colombia / Evaluation of antimicrobial susceptibility of Salmonella spp. strains isolated from pork carcasses on Colombia

    Directory of Open Access Journals (Sweden)

    Paula M. Bermúdez D

    2014-01-01

    Full Text Available Objetivo: el estudio buscó establecer patrones de resistencia antimicrobiana de 155 cepas de Salmonella spp., aisladas de la superficie de canales de cerdo, procedentes de plantas de beneficio en Colombia. Metodología: mediante el método de difusión en disco (Bauer et. Kirby, 1966 se evaluaron nueve antimicrobianos: Amoxicilina y ácido clavulánico (30 ug, Ampicilina (10 ug, Ceftiofur (30 ug, Ciprofloxacina (5 ug, Cloranfenicol (30 ug, Florfenicol (30 ug, Gentamicina (10 ug, Sulfadiazina y Trimetoprim (25 ug y Tetraciclina (30 ug. Resultados: los resultados confirmaron la presencia de cepas multiresistentes de Salmonella spp. de origen porcino, mostrando 30 patrones diferentes de multiresistencia; el más común fue Ampicilina, Amoxicilina, Cloranfenicol, Florfenicol y Tetraciclina en el 16,77% (n=26 de las cepas. Tetraciclina y Florfenicol fueron los antimicrobianos menos efectivos en el 94,84% (n=147 y 47,74% (n=74 de cepas resistentes, respectivamente. Discusión: se deben consolidar los sistemas de monitoreo, y de vigilancia y control de las resistencias antimicrobianas para prevenir, con un enfoque de cadena productiva, la diseminación de cepas multiresistentes en alimentos de origen animal, como parte integral del sistema de gestión de inocuidad de los alimentos en Colombia. - Objetivo: el estudio buscó establecer patrones de resistencia antimicrobiana de 155 cepas de Salmonella spp., aisladas de la superficie de canales de cerdo, procedentes de plantas de beneficio en Colombia. Metodología: mediante el método de difusión en disco (Bauer et. Kirby, 1966 se evaluaron nueve antimicrobianos: Amoxicilina y ácido clavulánico (30 ug, Ampicilina (10 ug, Ceftiofur (30 ug, Ciprofloxacina (5 ug, Cloranfenicol (30 ug, Florfenicol (30 ug, Gentamicina (10 ug, Sulfadiazina y Trimetoprim (25 ug y Tetraciclina (30 ug. Resultados: los resultados confirmaron la presencia de cepas multiresistentes de Salmonella spp. de origen porcino, mostrando

  10. Communication among Oral Bacteria

    Science.gov (United States)

    Kolenbrander, Paul E.; Andersen, Roxanna N.; Blehert, David S.; Egland, Paul G.; Foster, Jamie S.; Palmer, Robert J.

    2002-01-01

    Human oral bacteria interact with their environment by attaching to surfaces and establishing mixed-species communities. As each bacterial cell attaches, it forms a new surface to which other cells can adhere. Adherence and community development are spatiotemporal; such order requires communication. The discovery of soluble signals, such as autoinducer-2, that may be exchanged within multispecies communities to convey information between organisms has emerged as a new research direction. Direct-contact signals, such as adhesins and receptors, that elicit changes in gene expression after cell-cell contact and biofilm growth are also an active research area. Considering that the majority of oral bacteria are organized in dense three-dimensional biofilms on teeth, confocal microscopy and fluorescently labeled probes provide valuable approaches for investigating the architecture of these organized communities in situ. Oral biofilms are readily accessible to microbiologists and are excellent model systems for studies of microbial communication. One attractive model system is a saliva-coated flowcell with oral bacterial biofilms growing on saliva as the sole nutrient source; an intergeneric mutualism is discussed. Several oral bacterial species are amenable to genetic manipulation for molecular characterization of communication both among bacteria and between bacteria and the host. A successful search for genes critical for mixed-species community organization will be accomplished only when it is conducted with mixed-species communities. PMID:12209001

  11. PATHOGENICITY OF BIOFILM BACTERIA

    Science.gov (United States)

    There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

  12. Bacteria-surface interactions.

    Science.gov (United States)

    Tuson, Hannah H; Weibel, Douglas B

    2013-05-14

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.

  13. Antifreeze Proteins of Bacteria

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Antifreeze Proteins of Bacteria. M K Chattopadhyay. General Article Volume 12 Issue 12 December 2007 pp 25-30. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/012/12/0025-0030 ...

  14. The friendly bacteria within us Commensal bacteria of the intestine ...

    Indian Academy of Sciences (India)

    Balance of bacterial species in the gut · Immunosensory detection of intestinal bacteria · Pathogenic bacteria release interleukin-8 from HT-29 cells · Lactobacillus GG prevents the IL-8 release in response to pathogens · Effect of probiotic bacteria on chemokine response of epithelia to pathogens · PCR array studies in colon ...

  15. 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.

  16. 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

  17. Caracterización de la comunidad bacteriana aerobia en sanguijuelas (Hirudinea, Haementeria sp. (Glossiphoniidae y Oxytychus ornatus (Macrobdellidae de El Bagre, Antioquia = Characterization of the aerobic bacterial community in leeches Haementeria sp (Hirudinea: Glossiphoniidae y Oxytychus ornatus (Hirudinea: Macrobdellidae de El Bagre, Antioquia

    Directory of Open Access Journals (Sweden)

    López Isaza, Laura Patricia

    2012-01-01

    Full Text Available Se ha incrementado el uso terapéutico de las sanguijuelas y se ha demostrado que ellas pueden inocular bacterias causantes de infecciones en el 20% de los pacientes. El hallazgo en Antioquia de dos especies de sanguijuelas promisorias para hirudoterapia motivó este estudio para identificar las bacterias en la superficie, la probóscide y el intestino de estos anélidos y evaluar su sensibilidad a antibióticos. Las sanguijuelas estudiadas se identificaron como Haementeria sp., y Oxytychus ornatus. Muestras de la superficie, boca e intestino de ambos anélidos se inocularon en agar sangre, agar sangre con ampicilina y agar eosina azul de metileno. La identificación de las bacterias y su sensibilidad a antibióticos se evaluaron por el método automatizado Vitek (Biomerieux®. Se hicieron en total 26 aislamientos pertenecientes a 12 especies de nueve géneros. Enterobacter cloacae fue la especie más frecuente en ambos anélidos. Las bacterias fueron sensibles a los antibióticos comúnmente empleados en las infecciones causadas por este tipo de microorganismos. Se sugiere hacer profilaxis con antibióticos en los pacientes que reciban terapia con los anélidos investigados e implementar los protocolos estandarizados para el lavado de los animales antes de su uso y para el aseo de los acuarios en donde se los mantenga.

  18. Diversidad de bacterias cultivables con capacidad de degradar hidrocarburos de la playa de Caleta Córdova, Argentina

    Directory of Open Access Journals (Sweden)

    Graciela N. Pucci

    2011-05-01

    Full Text Available En el presente trabajo se estudiaron las comunidades bacterianas aisladas de agua de mar y sedimentos intermareales de Caleta Córdova, norte de Comodoro Rivadavia, Argentina. Tres sitios fueron muestreados estacionalmente entre los años 2005 y 2006; el primer sitio fue una playa pública, el segundo sitio cerca de un puerto pesquero y el tercero cerca de una boya de toma de petróleo. Las comunidades bacterianas fueron determinadas en base a las diferencias en la composición de ácidos grasos de membrana, las bacterias fueron identificadas por medio del Sistema Sherlock MIDI, y el potencial de las comunidades para la utilización de hidrocarburos por la mineralización de gasoil, petróleo, kerosene, aceite lubricante y nafta. Las mineralizaciones evidenciaron la capacidad de los microorganismos para la degradación de hidrocarburos en dos de los sitios estudiados. Se aislaron 251 cepas de las que se lograron identificar 124 correspondientes a 24 géneros y 40 especies; la más frecuente fue Pseudoalteromonas.

  19. Functional amyloids in bacteria.

    Science.gov (United States)

    Romero, Diego; Kolter, Roberto

    2014-06-01

    The term amyloidosis is used to refer to a family of pathologies altering the homeostasis of human organs. Despite having a name that alludes to starch content, the amyloid accumulations are made up of proteins that polymerize as long and rigid fibers. Amyloid proteins vary widely with respect to their amino acid sequences but they share similarities in their quaternary structure; the amyloid fibers are enriched in β-sheets arranged perpendicular to the axis of the fiber. This structural feature provides great robustness, remarkable stability, and insolubility. In addition, amyloid proteins specifically stain with certain dyes such as Congo red and thioflavin-T. The aggregation into amyloid fibers, however, it is not restricted to pathogenic processes, rather it seems to be widely distributed among proteins and polypeptides. Amyloid fibers are present in insects, fungi and bacteria, and they are important in maintaining the homeostasis of the organism. Such findings have motivated the use of the term "functional amyloid" to differentiate these amyloid proteins from their toxic siblings. This review focuses on systems that have evolved in bacteria that control the expression and assembly of amyloid proteins on cell surfaces, such that the robustness of amyloid proteins are used towards a beneficial end. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  20. Selección de cepas de rizobios aisladas de ecosistemas ganaderos de Canadá, inoculadas en trigo (Triticum aestivum, L.. Selection of rhizobium strains isolated from livestock ecosystems of Canada, inoculated to wheat (Triticum aestivum L.

    Directory of Open Access Journals (Sweden)

    C.J Bécquer

    2007-06-01

    Full Text Available Se efectuó un experimento de campo con el objetivo de seleccionar cepas de rizobios inoculadas en trigo (Triticum aestivum, L., var. Cuba-204. Se evaluaron varios indicadoress agroproductivos de la planta, tales como: peso seco aéreo, longitud del tallo, rendimiento de granos, peso de 1000 granos y rendimiento de nitrógeno. Como criterio de selección de los mejores tratamientos se consideraron los valores estadísticamente superiores al control fertilizado. Se utilizaron cuatro cepas de referencia, pertenecientes a diferentes géneros y especies de rizobios, y 10 cepas nativas, pertenecientes al género Sinorhizobium, que fueron aisladas de raíces de leguminosas (Melilotus y Medicago, adaptadas a ecosistemas ganaderos de Alberta, Canadá. Una de las cepas fue aislada de leguminosas adaptadas a suelos contaminados con hidrocarburos de esa misma zona geográfica. Las cepas crecieron en LMA y resuspendidas en CLM hasta lograr una UFC de 10(6 _ 10(8 cél/mL. Se utilizaron métodos estándar para la inoculación de cereales. Se aplicó un diseño experimental de bloques completamente aleatorizado, con 16 tratamientos y cuatro réplicas. Uno de los tratamientos se fertilizó con 150 kg/ha (NH4NO3. Se utilizó análisis de varianza. Las diferencias entre medias fueron halladas por la prueba LSD de Fisher (pA field experiment was carried out in order to select rhizobial strains inoculated to wheat (Triticum aestivum, L., var. Cuba-204. Several parameters of agricultural significance were assessed, such as: aerial dry weight, length of stems, grain yield, weight of 1 000 grains and nitrogen yield. As selection criterion of the best treatments, the statistically higher values compared to the fertilized control were considered. Four reference strains, belonging to several rhizobial genus and species were used, as well as ten native strains, belonging to Sinorhizobium that were isolated from roots of legumes (Melilotus and Medicago, adapted to Canadian

  1. Aislamiento y caracterización de cepas de rizobios aisladas de diferentes leguminosas en la región de Cascajal, Villa Clara Isolation and characterization of rhizobia strains isolated from different legumes in the Cascajal region, Villa Clara

    Directory of Open Access Journals (Sweden)

    Pérez Guianeya

    2008-06-01

    Full Text Available Se aislaron 19 cepas de rizobio a partir de los nódulos de las leguminosas Canavalia ensiformis, Stylosanthes guianensis, Centrosema molle, Pueraria phaseoloides y Macroptilium atropurpureum, con el objetivo de obtener inoculantes efectivos para dichos cultivos en suelos ácidos. Para la caracterización de los aislados bacterianos se estudiaron sus características micromorfológicas, tintoriales y culturales, así como algunas respuestas fisiológico-bioquímicas, tales como la excreción de ácido o base al medio de cultivo y el ensayo de la cetolactasa. Se hizo un ensayo de nodulación in vitro con cada una de las leguminosas para determinar la efectividad de los aislados. De acuerdo con las características culturales, la tasa de crecimiento en medio LMA y la producción de ácido o base, los aislados obtenidos pudieran pertenecer a los géneros Bradyrhizobium y Rhizobium y/o Sinorhizobium. La prueba de la cetolactasa permitió conocer que ninguno de los aislados en estudio pertenece al género Agrobacterium. El ensayo con plantas inoculadas mostró que todas las cepas aisladas fueron efectivas en la nodulación, ya que nodularon en las leguminosas probadas. Se concluye que de las cepas aisladas 11 pudieran pertenecer al género Bradyrhizobium, mientras que las ocho restantes comparten características similares con los géneros Rhizobium y/o Sinorhizobium; todos los aislados fueron efectivos en la nodulación y pueden considerarse cepas promisorias para la obtención de inoculantes para las leguminosas forrajeras en estudio.Nineteen rhizobium strains were isolated from the nodules of the legumes Canavalia ensiformis, Stylosanthes guianensis, Centrosema molle, Pueraria phaseoloides and Macroptilium atropurpureum, with the objective of obtaining effective inoculants for such crops in acid soils. For the characterization of the bacterial isolates, their micromorphological, staining and cultural characteristics were studied, as well as some

  2. Determinación de las condiciones de crecimiento in vitro de una cepa probiótica (Lactobacillus delbruekii subsp. bulgaricus aislada del tracto intestinal de terneros (Bos taurus

    Directory of Open Access Journals (Sweden)

    José Ávila

    2010-07-01

    Full Text Available El objetivo de este estudio fue conocer el efecto de la temperatura, pH y la concentración de inóculo sobre el crecimiento in vitro de una cepa probiótica (Lactobacillus delbruekii subsp. bulgaricus aislada del intestino delgado de terneros. Para ello se utilizó en el primer caso, el método de superficie de respuesta para determinar las condiciones de pH y temperatura óptimas de la cepa, y en el segundo, un diseño experimental completamente aleatorizado considerando el factor concentración de inóculo inicial a seis niveles, donde el crecimiento (en medio De Man, Rogosa y Sharpe expresado en unidades de Absorbancia, constituyó la variable respuesta; presentándose una máxima respuesta (0,806 uA para 5 % de concentración inicial de inóculo. Los valores de pH y temperatura utilizados permitieron el establecimiento de una zona óptima de crecimiento in vitro en los siguientes intervalos, pH entre 5,1 y 5,6; y temperatura entre 38,0 y 41,5 °C, donde el máximo crecimiento se obtuvo a pH 5,31 y a 39,38 °C. Por otro lado se encontraron incrementos significativos del crecimiento in vitro (p < 0,05 a medida que se utiliza menor concentración de inóculo inicial. Con la información obtenida se espera incrementar los rendimientos de la cepa y así promover la producción de productos probióticos para el consumo animal en Venezuela.

  3. Una nueva especie de Euglena (Euglenozoa: Euglenales aislada de ambientes extremófilos en las Pailas de Barro del Volcán Rincón de la Vieja, Costa Rica

    Directory of Open Access Journals (Sweden)

    Ana Sittenfeld

    2004-03-01

    Full Text Available Se describe una nueva especie de euglena aislada de las Pailas de Barro Caliente del Volcán Rincón de la Vieja, Costa Rica. Esta especie se caracteriza por habitar sitios ácidos y calientes. Euglena pailasensis sp. nov. tiene como características principales: la ausencia de flagelos, presencia de filamentos similares a "pilis", presencia de cloroplastos con pirenoides atravesados por varios tilacoides, además, es termotolerante y acido-tolerante. Los análisis filogenéticos para el gen ADNr 18S y la secuencia del gen para la enzima Gap C indican que la nueva especie está relacionada con E. mutabilis. Las características taxonómicas basadas en la morfología, biología y secuencia del ADNr 18S y los genes GAP C, son discutidas y comparadas con otras especies relativamente cercanas al géneroAnew species of euglena isolated from a hot and acid mud pool located in Las Pailas de Barro, Volcán Rincón de la Vieja, Costa Rica is described. This species inhabits hot and acid environments. Euglena pailasensis sp. nov. main features are: the absence of flagella, the presence filaments like "pilis", the presence of chloroplasts with pyrenoids crossed by several tylakoids, and acid and heat tolerance. Molecular phylogeny studies using 18S rDNA and Gap C genes indicated that the new species is related to E mutabilis. Its taxonomic characters based on morphology, biology and sequence of the 18S rDNA and Gap C genes are discussed and compared with other closely related species of the genus

  4. Valoración de desinfectantes mediante el método dilución-neutralización en cepas de Salmonella spp. aisladas en plantas de beneficio porcino

    Directory of Open Access Journals (Sweden)

    Andrea Paola Rodríguez Triviño

    2011-06-01

    Full Text Available La salmonelosis es una enfermedad muy importante, causante de problemas de salud pública ya que produce fiebres entéricas, gastroenteritis, bacteriemia, infecciones localizadas y estado de portador crónico, además se han informado como fuentes de contaminación los huevos, las carnes y la leche, tres de los alimentos más importantes consumidos por las personas. Por tal razón es importante determinar en la industria de los alimentos la susceptibilidad de Salmonella spp. a los desinfectantes, con el fin de contribuir a elaborar programas de prevención y control de este microorganismo, haciéndose necesaria la evaluación de su acción en cepas de Salmonella spp., en especial sobre aquellas transmitidas por los alimentos, además se debe medir la eficacia de los tipos de desinfectantes mediante el ensayo cuantitativo de suspensión para la evaluación de la actividad bactericida, en especial cuando a futuro se tenga como objetivo, evaluar el uso de desinfectantes en cepas de Salmonella spp. aisladas de plantas de beneficio porcino. Así que una vez se seleccionen las plantas de beneficio porcino objeto de la medición, en éstas se debe aislar una cantidad representativa de cepas de Salmonella spp., para someterlas a los diversos tipos de desinfectantes. El objetivo de la presente revisión es comparar la eficacia de tipos de desinfectantes que cuentan con un principio activo de amonio cuaternario y ácido peracético. Esperando que en futuros ensayos, por el método a nivel in vitro se puede comprobar la eficacia de los mismos.

  5. Valoración de desinfectantes mediante el método dilución-neutralización en cepas de Salmonella spp. aisladas en plantas de beneficio porcino

    Directory of Open Access Journals (Sweden)

    Jairo Humberto López Vargas

    2011-01-01

    Full Text Available La salmonelosis es una enfermedad muy importante, causante de problemas de salud pública ya que produce fiebres entéricas, gastroenteritis, bacteriemia, infecciones localizadas y estado de portador crónico, además se han informado como fuentes de contaminación los huevos, las carnes y la leche, tres de los alimentos más importantes consumidos por las personas. Por tal razón es importante determinar en la industria de los alimentos la susceptibilidad de Salmonella spp. a los desinfectantes, con el fin de contribuir a elaborar programas de prevención y control de este microorganismo, haciéndose necesaria la evaluación de su acción en cepas de Salmonella spp., en especial sobre aquellas transmitidas por los alimentos, además se debe medir la eficacia de los tipos de desinfectantes mediante el ensayo cuantitativo de suspensión para la evaluación de la actividad bactericida, en especial cuando a futuro se tenga como objetivo, evaluar el uso de desinfectantes en cepas de Salmonella spp. aisladas de plantas de beneficio porcino. Así que una vez se seleccionen las plantas de beneficio porcino objeto de la medición, en éstas se debe aislar una cantidad representativa de cepas de Salmonella spp., para someterlas a los diversos tipos de desinfectantes. El objetivo de la presente revisión es comparar la eficacia de tipos de desinfectantes que cuentan con un principio activo de amonio cuaternario y ácido peracético. Esperando que en futuros ensayos, por el método a nivel in vitro se puede comprobar la eficacia de los mismos.

  6. Determinación de las condiciones de crecimiento in vitro de una cepa probiótica (Lactobacillus delbruekii subsp. bulgaricus aislada del tracto intestinal de terneros (Bos taurus

    Directory of Open Access Journals (Sweden)

    José Ávila

    2010-06-01

    Full Text Available El objetivo de este estudio fue conocer el efecto de la temperatura, pH y la concentración de inóculo sobre el crecimiento in vitro de una cepa probiótica (Lactobacillus delbruekii subsp. bulgaricus aislada del intestino delgado de terneros. Para ello se utilizó en el primer caso, el método de superficie de respuesta para determinar las condiciones de pH y temperatura óptimas de la cepa, y en el segundo, un diseño experimental completamente aleatorizado considerando el factor concentración de inóculo inicial a seis niveles, donde el crecimiento (en medio De Man, Rogosa y Sharpe expresado en unidades de Absorbancia, constituyó la variable respuesta; presentándose una máxima respuesta (0,806 uA para 5 % de concentración inicial de inóculo. Los valores de pH y temperatura utilizados permitieron el establecimiento de una zona óptima de crecimiento in vitroen los siguientes intervalos, pH entre 5,1 y 5,6; y temperatura entre 38,0 y 41,5 °C, donde el máximo crecimiento se obtuvo a pH 5,31 y a 39,38 °C. Por otro lado se encontraron incrementos significativos del crecimiento in vitro (p < 0,05 a medida que se utiliza menor concentración de inóculo inicial. Con la información obtenida se espera incrementar los rendimientos de la cepa y así promover la producción de productos probióticos para el consumo animal en Venezuela.

  7. 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...... 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...

  8. 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...... 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 intestinal microbiota...

  9. Susceptibility to rifaximin and other antimicrobials of bacteria isolated in patients with acute gastrointestinal infections in Southeast Mexico

    Directory of Open Access Journals (Sweden)

    O. Novoa-Farias

    2017-07-01

    Full Text Available Introduction: Enteropathogenic bacteria isolated in Mexico City have shown a high rate of resistance to different antibiotics, with the exception of rifaximin (RIF. RIF is a nonabsorbable antibiotic that reaches high fecal concentrations (≈ 8,000 μg/g. Susceptibility to antimicrobials can vary in different geographic regions. Aim: To study the susceptibility to rifaximin and other antimicrobials of enteropathogenic bacteria isolated in patients with acute diarrhea in the southeastern region of Mexico. Material and methods: A total of 614 strains of bacteria isolated from patients with acute diarrhea from 4 cities in Southeast Mexico were analyzed. An antibiogram with the following antibiotics was created: ampicillin (AMP, trimethoprim/sulfamethoxazole (T-S, neomycin (NEO, furazolidone (FUR, ciprofloxacin (CIP, chloramphenicol (CHL, and fosfomycin (FOS, assessed through the agar diffusion method at the standard concentrations recommended by the Clinical and Laboratory Standards Institute (CLSI and the American Society for Microbiology (ASM, and RIF, assessed through microdilution at 4 concentrations. Results: The bacteria were Escherichia coli (55%, as the majority, in all its pathogenic variants, Shigella (16.8%, Salmonella (15.3%, Aeromonas (7.8%, and less than 5% Campylobacter, Yersinia, Vibrio, and Plesiomonas. The accumulated overall susceptibility to RIF was 69.1, 90.8, 98.9, and 100% at concentrations of 100, 200, 400, and 800 μg/ml, respectively. Overall susceptibility to other antibiotics was FOS 82.8%, CHL 76.8%, CIP 73.9%, FUR 64%, T-S 58.7%, NEO 55.8%, and AMP 23.8%. Susceptibility to RIF at 400 and 800 μg was significantly greater than with the other antimicrobials (P 98% of the bacterial strains and a high frequency of resistance to several common antimicrobials. Resumen: Antecedentes: Bacterias enteropatógenas aisladas en la Ciudad de México han mostrado una alta tasa de resistencia a diversos antibi

  10. Radiation-resistant asporogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K [Tokyo Univ. (Japan). Faculty of Agriculture

    1975-09-01

    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.

  11. Radiation-resistant asporogenic bacteria

    International Nuclear Information System (INIS)

    Yano, Keiji

    1975-01-01

    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.)

  12. Acoustofluidic bacteria separation

    International Nuclear Information System (INIS)

    Li, Sixing; Huang, Tony Jun; Ma, Fen; Zeng, Xiangqun; Bachman, Hunter; Cameron, Craig E

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device. (paper)

  13. Acoustofluidic bacteria separation

    Science.gov (United States)

    Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.

  14. 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.

  15. Ecophysiology of the Anammox Bacteria

    NARCIS (Netherlands)

    Kartal, M.B.

    2008-01-01

    Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium to dinitrogen gas with nitrite as the electron acceptor. These bacteria are the key players in the global nitrogen cycle, responsible for the most of nitrogen production in natural ecosystems. The anammox process is also a

  16. Money and transmission of bacteria.

    NARCIS (Netherlands)

    Gedik, H.; Voss, T.A.; Voss, A.

    2013-01-01

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria

  17. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  18. METHODS FOR DETECTING BACTERIA USING POLYMER MATERIALS

    NARCIS (Netherlands)

    Van Grinsven Bart Robert, Nicolaas; Cleij, Thomas

    2017-01-01

    A method for characterizing bacteria includes passing a liquid containing an analyte comprising a first bacteria and a second bacteria over and in contact with a polymer material on a substrate. The polymer material is formulated to bind to the first bacteria, and the first bacteria binds to the

  19. Serovariedades y patrones de susceptibilidad a los antimicrobianos de cepas de Salmonella aisladas de alimentos en Cuba Serotypes and antimicrobial susceptibility patterns of Salmonella strains isolated from food in Cuba

    Directory of Open Access Journals (Sweden)

    Yamila Puig Peña

    2011-12-01

    Full Text Available Se describen los serotipos de 178 cepas de Salmonella enterica aisladas de alimentos en diferentes regiones de Cuba entre enero de 2008 y diciembre de 2009, y el patrón de susceptibilidad a los antimicrobianos de 100 aislados seleccionados mediante muestreo por estratos. Se identificaron 20 serovariedades de Salmonella entre las que predominaron S. Enteritidis (23%; S. Agona (13,5% y S. London (11,2%. Del total, 75% de las cepas fueron resistentes o presentaron resistencia intermedia a al menos uno de los fármacos probados, en el siguiente orden, según su frecuencia: tetraciclina (70,7%; ampicilina (22,7% y ácido nalidíxico (14,7%. Se identificaron 10 patrones de resistencia diferentes y predominaron las cepas resistentes o conresistencia intermedia a un fármaco (89,3%. Tres cepas (S. Infantis, S. Derby y S. Enteritidis fueron multirresistentes y una, de S. Enteritidis, dio un resultado no sensible al ácido nalidíxico y la ciprofloxacina. Se destaca la necesidad de extremar la vigilancia sanitaria integrada en el país para el control de la salmonelosis.The serotypes of 178 isolates of Salmonella enterica taken from food in different regions of Cuba between January 2008 and December 2009 were identified, and the antimicrobial susceptibility pattern of 100 selected isolates was determined by strata sampling. A total of 20 Salmonella serotypes were identified, with a predominance of S. Enteritidis (23%, S. Agona (13.5%, and S. London (11.2%. Of all the strains, 75% were resistant or presented intermediate resistance to at least one of the drugs tested, in the following order: tetracycline (70.7%, ampicillin (22.7%, and nalidixic acid (14.7%. Ten different resistance patterns were identified. The most frequent patterns corresponded to strains that were either drugresistant or had intermediate resistance (89.3%. Three strains (identified as S. Infantis, S. Derby, and S. Enteritidis were multiresistant, and one of them, S. Enteritidis, was

  20. Review on SERS of Bacteria

    Directory of Open Access Journals (Sweden)

    Pamela A. Mosier-Boss

    2017-11-01

    Full Text Available Surface enhanced Raman spectroscopy (SERS has been widely used for chemical detection. Moreover, the inherent richness of the spectral data has made SERS attractive for use in detecting biological materials, including bacteria. This review discusses methods that have been used to obtain SERS spectra of bacteria. The kinds of SERS substrates employed to obtain SERS spectra are discussed as well as how bacteria interact with silver and gold nanoparticles. The roll of capping agents on Ag/Au NPs in obtaining SERS spectra is examined as well as the interpretation of the spectral data.

  1. 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

  2. Electron transport chains of lactic acid bacteria

    NARCIS (Netherlands)

    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

  3. Gut Bacteria Affect Immunotherapy Response

    Science.gov (United States)

    Three new studies have identified intestinal bacteria that appear to influence the response to checkpoint inhibitors. This Cancer Currents blog post explains how the researchers think their findings could be used to improve patients’ responses to these immunotherapy drugs.

  4. hydroxyalkanoate (PHAs) producing bacteria isolated

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    Jul 4, 2007 ... ium (MSM), having inhibitors for Gram positive bacteria and fungi and a mixed ... Two techniques were used for detecting the presence of polymer: staining ... was saline solution at 600 nm wavelength on VARIAN DSM 100.

  5. 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....... The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  6. Anaerobic bacteria that dechlorinate perchloroethene.

    Science.gov (United States)

    Fathepure, B Z; Nengu, J P; Boyd, S A

    1987-01-01

    In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224

  7. Interferencia entre bacterias comensales de faringe y patogénesis de oído medio en un modelo animas de otitis media

    Directory of Open Access Journals (Sweden)

    LM Villafane

    2013-01-01

    Full Text Available Objetivo: determinar in vivo la interacción entre bacterias comensales aisladas  de faringe de niños sanos y S. pneumoniae, en un modelo animal (Chinchilla laniger de otitis media. Metodos: estudio experimental Intervenciones: Suspensiones de los serotipos 18A y 9V de Spn fueron inyectados intra-peritonealmente en dos chinchillas y luego recuperados mediante cultivo de órganos y sangre de las mismas. Empleando suspensiones de las cepas animalizadas se inocularon intranasalmente cuatro chinchillas, y solo a dos de ellas se le inoculo una mezcla de las bacterias comensales (Streptococcus mitis, Streptococcus parasanguinis. Con un otoscopio se examinó la evolución de la infección a los 7 y 14 días. Se sacrificaron los animales y se tomaron muestras de los oídos para un examen histológico. Resultados: Mediante otoscopia, se observó al día 14 que todos presentaron una membrana timpánica hiperémica sin efusión, presentándose con mayor intensidad en aquellos que recibieron el tratamiento. La histología confirmó que la administración del tratamiento no evitó que la infección evolucionara, advirtiéndose que las infectadas con el serotipo 8A y tratadas fueron las que presentaron el tejido epitelial menos comprometido respecto al resto. Conclusiones: Spn y las bacterias comensales podrían establecer una relación competitiva, y el efecto moderador en la progresión de la infección de otitis media dependería del serotipo involucrado.

  8. INTERFERENCIA ENTRE BACTERIAS COMENSALES DE FARINGE Y PATÓGENAS DE OÍDO MEDIO EN UN MODELO ANIMAL DE OTITIS MEDIA

    Directory of Open Access Journals (Sweden)

    LM Villafañe

    2012-01-01

    Full Text Available Objetivo: determinar in vivo la interacción entre bacterias comensales aisladas de faringe de niños sanos y S. pneumoniae, en un modelo animal (Chinchilla laniger de otitis media. Metodos: estudio experimental Intervenciones: Suspensiones de los serotipos 18A y 9V de Spn fueron inyectados intra-peritonealmente en dos chinchillas y luego recuperados mediante cultivo de órganos y sangre de las mismas. Empleando suspensiones de las cepas animalizadas se inocularon intranasalmente cuatro chinchillas, y solo a dos de ellas se le inoculo una mezcla de las bacterias comensales (Streptococcus mitis, Streptococcus parasanguinis. Con un otoscopio se examinó la evolución de la infección a los 7 y 14 días. Se sacrificaron los animales y se tomaron muestras de los oídos para un examen histológico. Resultados: Mediante otoscopia, se observó al día 14 que todos presentaron una membrana timpánica hiperémica sin efusión, presentándose con mayor intensidad en aquellos que recibieron el tratamiento. La histología confirmó que la administración del tratamiento no evitó que la infección evolucionara, advirtiéndose que las infectadas con el serotipo 8A y tratadas fueron las que presentaron el tejido epitelial menos comprometido respecto al resto. Conclusiones: Spn y las bacterias comensales podrían establecer una relación competitiva, y el efecto moderador en la progresión de la infección de otitis media dependería del serotipo involucrado.

  9. ESTABILIDAD DE ALMACENAMIENTO DE ENSILADOS BIOLÓGICOS A PARTIR DE RESIDUOS DE PESCADO INOCULADOS CON BACTERIAS ÁCIDO-LÁCTICAS STORAGE STABILITY OF BIOLOGICAL SILAGE FROM FISH REMAINS ADDED WITH LACTIC ACID BACTERIA CULTURE

    Directory of Open Access Journals (Sweden)

    Veloza Gómez Luis Carlos

    2009-04-01

    Full Text Available Se elaboraron cuatro muestras por triplicado de ensilados biológicos para alimentación animal a partir de residuos de pescado, utilizando melaza como fuente de carbohidratos para el crecimiento de cuatro cepas de bacterias ácido-lácticas (BAL aisladas de los mismos, sometidos a un tiempo de incubación de 72 horas y temperatura de 35 °C (±2 °C para acidificar el producto como método de conservación. A continuación los ensilados se almacenaron durante 180 días a temperatura ambiente para evaluar la estabilidad en anaquel, por medio de análisis químicos, composición química proximal, aminograma, recuentos microbiológicos y algunos de tipo organoléptico del producto terminado. Las cepas fueron eficientes en el proceso de fermentación, causando inhibición del crecimiento de microorganismos indeseables y aportando características organolépticas agradables. El ensilado elaborado con la cepa C14 provocó el descenso del pH en menos de 72 horas de incubación. Ninguno de los productos sufrió deterioro evidente durante el almacenamiento; presentaron porcentajes aceptables de proteína, grasa, cenizas, carbohidratos y aminoácidos, que hacen del producto una fuente utilizable en formulaciones de alimentos para animales.Four biological silages samples for animal feeding were made from fish remains in triplicate, using molasses like source of carbohydrate for the growth of four lactic acid bacteria (LAB strains isolated from those remains and incubated during 72 hours and temperature of 35°C (±2°C to acidify the product as preservation method. Then, the silages were storage for 180 days at room temperature to asses the shelf stability by conducting chemical, proximal chemical composition, amine assessment, microbiological counting and some sensory evaluation in final product. Bacteria cultures were efficient in fermentation process causing inhibition growth of undesirable bacteria and giving pleasant sensory characteristics. The

  10. Infecciones por bacterias poco comunes y oncogénesis bacteriana

    Directory of Open Access Journals (Sweden)

    Horacio A. Lopardo

    Full Text Available La recuperación de algunos microorganismos de aislamiento esporádico en el laboratorio de microbiología clínica podría significar la existencia de algún defecto inmunitarioespecial en el paciente. Por ejemplo, se ha descrito una importante correlación entre Clostridium septicum y carcinoma de colon, y se han visto relacionadas con leucemias y linfomas a especies que aparecen casi siempre como contaminantes (Bacillus spp., Corynebacterium spp. y a otras raramente aisladas en otros contextos (Capnocytophaga spp.. Hay bacterias que se aíslan casi exclusivamente de pacientes con sida (Rhodococcus equi. Se ha observado una mayor frecuencia de infecciones por Campylobacter spp., Aeromonas spp. y estreptococos del grupo G y del grupo mitis en individuos con algún tipo de cáncer que en el resto de los pacientes. También hay bacterias que son marcadoras de algún cáncer no detectado o que afectan más a pacientes neutropénicos que a individuos normoinmunes. La alteración de la reacción inflamatoria, la linfoproliferación mediada por antígenos bacterianos y la inducción de hormonas que aumentan la proliferación de las células epiteliales podrían ser causas de la oncogénesis bacteriana. Los ejemplos clásicos son el adenocarcinoma gástrico inducido por Helicobacter pylori, la asociación de la bacteriemia por estreptococos del grupo bovis y el cáncer de colon y los linfomas de tejido linfoide asociado a mucosas (MALT en vinculación con especies de Helicobacter (MALT gástricos y con Chlamydophila spp. (MALT oculares. El aislamiento de alguno de estos patógenos debería ser un llamado de atención para inducir al estudio de alguna enfermedad maligna.

  11. ESTABILIDAD DE ALMACENAMIENTO DE ENSILADOS BIOLÓGICOS A PARTIR DE RESIDUOS DE PESCADO INOCULADOS CON BACTERIAS ÁCIDO -LÁCTICAS

    Directory of Open Access Journals (Sweden)

    MS Holguín

    2009-01-01

    Full Text Available Se elaboraron cuatro muestras por triplicado de ensilados biológicos para alimentación animal a partir de residuos de pescado, utilizando melaza como fuente de carbohidratos para el crecimiento de cuatro cepas de bacterias ácido-lácticas (BAL aisladas de los mismos, sometidos a un tiempo de incubación de 72 horas y temperatura de 35 °C (±2 °C para acidificar el producto como método de conservación. A continuación los ensilados se almacenaron durante 180 días a temperatura ambiente para evaluar la estabilidad en anaquel, por medio de análisis químicos, composición química proximal, aminograma, recuentos microbiológicos y algunos de tipo organoléptico del producto terminado. Las cepas fueron eficientes en el proceso de fermentación, causando inhibición del crecimiento de microorganismos indeseables y aportando características organolépticas agradables. El ensilado elaborado con la cepa C14 provocó el descenso del pH en menos de 72 horas de incubación. Ninguno de los productos sufrió deterioro evidente durante el almacenamiento; presentaron porcentajes aceptables de proteína, grasa, cenizas, carbohidratos y aminoácidos, que hacen del producto una fuente utilizable en formulaciones de alimentos para animales.

  12. Human body may produce bacteria.

    Science.gov (United States)

    Salerian, Alen J

    2017-06-01

    "Human body may produce bacteria" proposes that human body may produce bacteria and represent an independent source of infections contrary to the current paradigm of infectious disorders proposed by Louis Pasteur in 1880. The following observations are consistent with this hypothesis: A. Bidirectional transformations of both living and nonliving things have been commonly observed in nature. B. Complex multicellular organisms harbor the necessary properties to produce bacteria (water, nitrogen and oxygen). C. Physical laws suggest any previously observed phenomenon or action will occur again (life began on earth; a non living thing). D. Animal muscle cells may generate energy (fermentation). E. Sterilized food products (i.e. boiled eggs), may produce bacteria and fungus under special conditions and without any exposure to foreign living cells. "Human body may produce bacteria" may challenge the current medical paradigm that views human infectious disorders as the exclusive causative byproducts of invading foreign cells. It may also introduce new avenues to treat infectious disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Horizontal gene transfer between bacteria.

    Science.gov (United States)

    Heuer, Holger; Smalla, Kornelia

    2007-01-01

    Horizontal gene transfer (HGT) refers to the acquisition of foreign genes by organisms. The occurrence of HGT among bacteria in the environment is assumed to have implications in the risk assessment of genetically modified bacteria which are released into the environment. First, introduced genetic sequences from a genetically modified bacterium could be transferred to indigenous micro-organisms and alter their genome and subsequently their ecological niche. Second, the genetically modified bacterium released into the environment might capture mobile genetic elements (MGE) from indigenous micro-organisms which could extend its ecological potential. Thus, for a risk assessment it is important to understand the extent of HGT and genome plasticity of bacteria in the environment. This review summarizes the present state of knowledge on HGT between bacteria as a crucial mechanism contributing to bacterial adaptability and diversity. In view of the use of GM crops and microbes in agricultural settings, in this mini-review we focus particularly on the presence and role of MGE in soil and plant-associated bacteria and the factors affecting gene transfer.

  14. Índices fisiológicos associados com a "performance" aeróbia em corredores de "endurance": efeitos da duração da prova Índices fisiológicos asociados a la "performance" aerobia en competidores de "endurance": efectos de la duración de la prueba Physiological indexes associated with aerobic performance in endurance runners: effects of race duration

    Directory of Open Access Journals (Sweden)

    Benedito Sérgio Denadai

    2004-10-01

    .000m (17,9 ± 0,9 fueron significantemente diferentes. La regresión múltiple stepwise mostró que el LAn fue el único elemento de predicción de la performance de la v5.000m, explicando el 50% de la variación de esta performance. Para la v1.500m, el Tlim y la vVO2max explicaron el 88% de la variación de la performance. Con base en nuestros resultados, se puede concluir que la validez de los índices fisiológicos (VO2max, vVO2max, Tlim, EC y LAn, para la predicción de la performance aerobia de atletas de endurance depende de la distancia de la prueba (1.500 x 5.000m analizada.The aim of this study was to assess the validity of the maximal oxygen uptake (VO2max, the velocity at VO2max (vVO2max, time to exhaustion at vVO2max (Tlim, running economy (RE and anaerobic threshold (AnT to predict the aerobic performance of the endurance athletes. Fourteen well-trained long-distance runners (33.4 ± 4.4 yr.; 62.7 ± 4.3 kg; 166.1 ± 5.0 cm; VO2max = 60.4 ± 5.9 ml.kg-1.min-1 underwent the following tests: a simulated competitions in the distances of 1500 and 5000 m and; b laboratory treadmill tests to determine their VO2max, vVO2max, Tlim, EC and AnT. The velocities (km/h at vVO2max (18.7 + 0.8, LAn (17.3 + 1.1 v1500 m (19.9 + 0.8 and v5000 m (17.9 + 0.9 were significantly different. A stepwise multiple-regression analysis revealed that AnT alone was the best single predictor of v-5000 m and explained 50% of the variability in 5000 m running velocity. For v1.500 m, Tlim and vVO2max explained 88 % of the variability of the performance. We conclude that, in a group of well-trained long-distance runners, the validity of the physiological indexes (VO2max, vVO2max, Tlim, EC e LAn to predict the aerobic performance is dependent of the distance (1500 x 5000 m analyzed.

  15. Culture supernatants from V. cholerae O1 ElTor strains isolated from different geographic areas induce cell vacuolation and cytotoxicity Cepas de V. cholerae O1 biotipo ElTor aisladas de diferente origen geográfico inducen vacuolización celular y citotoxicidad

    Directory of Open Access Journals (Sweden)

    Jorge E Vidal

    2009-02-01

    Full Text Available OBJECTIVE: To investigate whether the HlyA-induced vacuolating effect is produced by V. cholerae O1 ElTor strains isolated from different geographic origins, including Mexico. MATERIAL AND METHODS: Supernatant-induced haemolysis, vacuolating activity and cytotoxicity in Vero cells were recorded. PCR, RFLP analysis and molecular cloning were performed. RESULTS: All ElTor strains analyzed induced cellular vacuolation. Ribotype 2 strains isolates from the U.S. gulf coast yielded the highest titer of vacuolating activity. Eight of nine strains were haemolytic, while all strains were PCR positive for the hlyA gene. We cloned the hlyA gene from two ElTor strains, a toxigenic (2514-88, ctxAB+ and a non-toxigenic Mexican strain (CM 91-3, ctxAB-. Supernatant from those recombinant E. coli strains induced haemolysis, cell vacuolation and cytotoxicity. RFLP-PCR analysis revealed similarities in the hlyA gene from all strains tested. CONCLUSION: The HlyA-induced vacuolating effect is a widespread phenotype of epidemic V. cholerae O1 ElTor strains.OBJETIVO: Analizar el efecto vacuolizante de cepas de V. cholerae O1 ElTor aisladas de diferente origen geográfico, incluyendo México. MATERIAL Y MÉTODOS: Se realizaron pruebas de hemolisis, vacuolización y citotoxicidad en células Vero, así como PCR, análisis por RFLP y clonación molecular. RESULTADOS: Todas las cepas indujeron el efecto vacuolizante. Las cepas del ribotipo 2, aisladas de las costas del Golfo en Estados Unidos, presentaron títulos altos de vacuolización. El gen hlyA fue amplificado en las nueve cepas mediante PCR, aunque sólo ocho fueron hemolíticas. Se clonó el gen hlyA de una cepa toxigénica (2514-88, ctxAB+ y de una cepa no toxigénica aislada en México (CM 91-3, ctxAB-. El sobrenadante de las clonas recombinantes indujo hemólisis, efecto vacuolizante y citotoxicidad. El RFLP mostró alta similitud del gen hlyA de las cepas estudiadas. CONCLUSIÓN: El efecto vacuolizante es un

  16. Analysis, simulation and control of electromagnetic transients in gas insulated substations in SF6 by means of grounding grid; Analisis, simulacion y control de transitorios electromagneticos en subestaciones aisladas en SF6 por medio de redes de tierra

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Martinez, Gaston

    2007-12-15

    operaciones de maniobra, originando el sobrevoltaje transitorio ultra rapido (VFTO) y el voltaje transitorio encapsulado (TEV). Esta investigacion se centra en disminuir la magnitud del VFTO y el TEV a traves del diseno y rediseno de redes de tierra para subestaciones aisladas en gas. El objetivo de este trabajo es el de disenar una red de tierra para una subestacion aerea y redisenarla para una subestacion GIS utilizando el modelo detallado de la subestacion en SF6 interconectado con la red de tierra aerea hasta conseguir, a traves de la adicion metodologica de varillas de tierra, disminuir el VFTO y el TVE dentro del GIS. Los resultados de la simulacion muestran que la red de tierra disenada permite disminuir considerablemente la magnitud del VFTO; sin embargo, este diseno no consigue atenuar adecuadamente la magnitud del TEV.

  17. 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....

  18. 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.

  19. Bacteria on the hands of school-age children at a Pediatric Hospitalization Unit Bacterias presentes en las manos de los niños en edad escolar en la Unidad de Internación Pediátrica Bactérias presentes nas mãos dos meninos em idade escolar na unidade de internação pediátrica

    Directory of Open Access Journals (Sweden)

    Marcela Cristina Candido De Almeida

    2012-07-01

    Full Text Available Objective. To estimate the prevalence of bacteria isolated in samples from the hands of school-age children at a hospitalization unit. Methodology. In 2009, strains were cultured from the hands of 90 school-age children at the pediatric hospitalization unit of Hospital Estadual Bauru (São Paulo, Brazil. After culture of the samples, the isolated bacteria were identified. Results. In 98% of the samples taken from the children, bacteria were isolated. Coagulase-negative Staphilococcus was isolated in 64% of the samples, followed by Staphilococcus aureus (5% and Pseudomonas aeruginosa (1%. Conclusion. In most of the samples from the children's hands, bacteria were isolated. Therefore, educative actions about hygiene habits in- and outside the hospital environment should be reinforced, aimed at children and their companions.Objetivo. Estimar la prevalencia de bacterias aisladas en las manos de los niños en edad escolar en una unidad de internación. Metodología. En 2009 se hicieron cultivos de las manos de 90 niños en edad escolar de la unidad de internación pediátrica del Hospital Estadual Bauru (São Paulo, Brasil. Se hizo cultivo de las muestras y posteriormente se realizó identificación de las bacterias aisladas. Resultados. En el 98% de las muestras tomadas a los niños se hicieron aislamientos de bacterias. Stafilococcus coagulasa negativa se aisló en el 64% de las muestras; Staphilococcus aureus, en un 5%, y Pseudomonas aeruginosa, en un 1%. Conclusión. En la mayor parte de las muestras de las manos de los niños internados se aislaron bacterias, por lo que se deben reforzar las acciones educativas a los niños y a sus acompañantes en relación con los hábitos de higiene en el ambiente hospitalario y fuera de él.Estimar a prevalência de bactérias isoladas em mostras das mãos dos meninos em idade escolar numa unidade de internação. Metodologia. Em 2009 se fizeram cultivos das mãos de 90 meninos em idade escolar da unidade de

  20. Estudio de la susceptibilidad a vancomicina de cepas de Staphyloccus spp., aisladas del hospital Antonio Patricio de Alcalá, Cumaná, estado Sucre | Vancomycin susceptibility study of Staphylococcus spp. Strains isolated from Antonio Patricio de Alcalá hospital, Cumaná, Sucre state

    Directory of Open Access Journals (Sweden)

    Lorena Abadia-Patiño

    2017-10-01

    Full Text Available De todas las cepas de Staphylocccus aureus almacenadas en el cepario del Laboratorio de Resistencia Bacteriana del IIBCAUDO, se analizaron 14 para determinar la disminución de susceptibilidad a vancomicina. Sesenta y cuatro por ciento de las cepas crecieron en el cribado de vancomicina. La CMI a vancomicina de las cepas estuvo entre 1 y 2 mg/L por microdilución. La CMI por dilución en agar fue entre 2 y 4 mg/L. La CMB de las cepas fue de 2 y 4 mg/L. Ninguna cepa fue tolerante. No se detectaron cepas hVISA por PAP-AUC. Se recomienda realizar el cribado de vancomicina en cepas aisladas de sitios estériles.

  1. Actividad “in vitro” de 10 antimicrobianos frente a bacterias anaerobias: Estudio multicéntrico, 1999-2002 “In vitro” activity of ten antimicrobial agents against anaerobic bacteria. A collaborative study, 1999-2002

    Directory of Open Access Journals (Sweden)

    M. Litterio

    2004-09-01

    Full Text Available Se evaluó la actividad de ampicilina, ampicilina-sulbactama, cefoxitina, ceftriaxona, imipenem, piperacilina, piperacilina-tazobactama, clindamicina, metronidazol y azitromicina frente a 166 cepas de bacterias anaerobias aisladas en 8 hospitales de Buenos Aires. Se estudiaron: Bacteroides grupo fragilis (65, Fusobacterium spp. (26, Prevotella spp. (21, Porphyromonas spp. (10, Clostridium difficile (10, otros clostridios (12 y cocos gram-positivos (22. Las CIMs se determinaron usando el método patrón de dilución en agar recomendado por el NCCLS, documento M11-A5. Los antibióticos más activos fueron metronidazol y piperacilina-tazobactama que exhibieron valores de CIM90£ 2 µg/ml y £ 4 µg/ml frente a los microorganismos gram-negativos y £ 2 µg/ml y £ 8 µg/ml frente a los microorganismos gram-positivos, respectivamente. Entre los b-lactámicos el orden de actividad frente a bacilos gram-negativos fue: imipenem > piperacilina > cefoxitina > ceftriaxona > ampicilina. En gram-positivos la actividad decreciente fue: piperacilina> imipenem > cefoxitina > ceftriaxona > ampicilina. La mayoría de las especies estudiadas mostraron distintos niveles de resistencia con clindamicina y azitromicina. Sin embargo, el 90% de las cepas de Fusobacterium nucleatum y Por-phyromonas spp. fue inhibido por una concentración de 0,125 µg/ml de clindamicina y azitromicina, respectivamente.The antimicrobial activity of ampicillin, ampicillin-sulbactam, cefoxitin, ceftriaxone, imipenem, piperacillin, piperacillin-tazobactam, clindamycin, metronidazole, and azitromycin was assesed against 166 strains of anaerobic bacteria recovered from eight hospitals in Buenos Aires. The strains studied were Bacteroidesfragilis group (65, Fusobacterium spp. (26, Prevotella spp. (21, Porphyromonas spp. (10, Clostridium difficile (10, other clostridia (12, and gram-positive cocci (22. The MICs were determined by the agar dilution method according to NCCLS document M11-A5

  2. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

    solely based on endospores of sulphate-reducing bacteria (SRB), which presumably constitute only a small fraction of the total thermophilic endospore community reaching cold environments. My PhD project developed an experimental framework for using thermophilic fermentative endospores (TFEs) to trace...

  3. Alternative sources of Legionella bacteria

    NARCIS (Netherlands)

    van Heijnsbergen, H.H.L.

    2017-01-01

    Legionella bacteria can cause Legionnaires’ disease (LD) in humans. Symptoms of LD can range from mild disease to severe pneumonia with sometimes fatal outcome. In the Netherlands, the most important infective agent is Legionella pneumophila. L. pneumophila infection is associated with aquatic

  4. 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...

  5. Automated radiometric detection of bacteria

    International Nuclear Information System (INIS)

    Waters, J.R.

    1974-01-01

    A new radiometric method called BACTEC, used for the detection of bacteria in cultures or in supposedly sterile samples, was discussed from the standpoint of methodology, both automated and semi-automated. Some of the results obtained so far were reported and some future applications and development possibilities were described. In this new method, the test sample is incubated in a sealed vial with a liquid culture medium containing a 14 C-labeled substrate. If bacteria are present, they break down the substrate, producing 14 CO 2 which is periodically extracted from the vial as a gas and is tested for radioactivity. If this gaseous radioactivity exceeds a threshold level, it is evidence of bacterial presence and growth in the test vial. The first application was for the detection of bacteria in the blood cultures of hospital patients. Data were presented showing typical results. Also discussed were future applications, such as rapid screening for bacteria in urine industrial sterility testing and the disposal of used 14 C substrates. (Mukohata, S.)

  6. Synthetic Biology in Streptomyces Bacteria

    NARCIS (Netherlands)

    Medema, Marnix H.; Breitling, Rainer; Takano, Eriko

    2011-01-01

    Actinomycete bacteria of the genus Streptomyces are major producers of bioactive compounds for the biotechnology industry. They are the source of most clinically used antibiotics, as well as of several widely used drugs against common diseases, including cancer . Genome sequencing has revealed that

  7. Deodorant bacteria; Des bacteries desodorisantes

    Energy Technology Data Exchange (ETDEWEB)

    Fanlo, J.L. [Ecole Nationale Superieure des Mines, 30 - Ales (France)

    1998-02-01

    Purifying bacteria: if this concept is not new, its application to gases cleansing has only been developed recently. This method allows to eliminate the volatile organic compounds and the gaseous effluents odors which come from industrial sites. Three bioreactors types exist at the present time. Their principles are explained. (O.M.) 6 refs.

  8. 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.

  9. 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).

  10. 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.

  11. Oligotrophic bacteria isolated from clinical materials.

    OpenAIRE

    Tada, Y; Ihmori, M; Yamaguchi, J

    1995-01-01

    Oligotrophic bacteria (oligotrophs) are microorganisms that grow in extremely nutritionally deficient conditions in which the concentrations of organic substances are low. Many oligotrophic bacteria were isolated from clinical materials including urine, sputum, swabbings of the throat, vaginal discharges, and others. Seventy-seven strains of oligotrophic bacteria from 871 samples of clinical material were isolated. A relatively higher frequency of isolation of oligotrophic bacteria was shown ...

  12. Identificación de bacterias productoras de Polihidroxialcanoatos (PHAs en suelos contaminados con desechos de fique

    Directory of Open Access Journals (Sweden)

    Silvia Alexandra Sánchez Moreno

    2012-07-01

    Full Text Available Título en ingles: Identification of polyhydroxyalkanoate-producing bacteria in soils contaminated with fique wastes Resumen: Los Polihidroxialcanoatos (PHAs son biopolímeros con características similares a los plásticos sintéticos, pero rápidamente biodegradables dado su origen microbiano. En esta investigación se aislaron 248 colonias bacteriales de suelos contaminados con residuos del beneficio de fique en Guarne (Antioquia, evaluándose su capacidad como productoras de PHAs. Se realizaron tinciones con rojo y azul de Nilo y detección por PCR del gen PhaC. Las bacterias positivas a dichas pruebas, fueron identificadas utilizando análisis filogenético de secuencias de 16S del ADNr y pruebas bioquímicas. Finalmente, se evaluó, mediante cromatografía de gases con detector selectivo de masas GC-MS/SIM, la naturaleza química del biopolímero, a partir de la biomasa generada en un ensayo de fermentación en cultivo sumergido, con medio mínimo de sales suplementado con glucosa como fuente de carbono. Cuatro cepas de los morfotipos bacteriales encontrados, presentaron potencial para producir PHAs, de los cuales dos fueron identificados como miembros de la especie Bacillus megaterium, uno como B. mycoides y el otro como Gordonia sp. El gen PhaC se detectó en los dos aislamientos de B. megaterium. El análisis cromatográfico permitió detectar al Polihidroxibutirato (PHB como el principal componente de los PHAs presentes en B. megaterium, cuantificándose entre 63.8 mg/g y 95.3 mg/g de PHB en los ensayos de fermentación. Las bacterias aisladas tienen potencial en la producción de PHAs a partir de residuos agroindustriales, incluyendo el jugo de fique, lo que contribuiría a la reducción de su condición contaminante. Palabras clave: ADNr 16S; Bacillus; biopolímeros; Furcraea bedinghausii; PhaC. Abstract: Polyhydroxyalkanoates (PHAs are biodegradable biopolymers of bacterial origin with properties similar to conventional plastics. In

  13. Geobiology of Marine Magnetotactic Bacteria

    Science.gov (United States)

    2006-06-01

    prokaryotic cells of diverse phylogeny when grown in media containing 45 1mM iron, suggesting some kind of detoxification function . The inclusions were...salt marsh productivity. FISH also showed that aggregates consist of genetically identical cells. QPCR data indicated that populations are finely...my advisor Katrina Edwards for taking a chance on someone who initially knew nothing about magnetotactic bacteria, microbial ecology , or microbiology

  14. Caracterización por PCR- múltiple del grupo filogenético de Escherichia coli uropatógena aisladas de pacientes ambulatorios de Bucaramanga, Santander

    Directory of Open Access Journals (Sweden)

    Alexandra Serrano

    2016-06-01

    Full Text Available Introducción: Las infecciones del tracto urinario son consideradas actualmente como una de las enfermedades infecciosas más comunes. En general se acepta que los agentes infecciosos con los cuales se asocia se encuentran presentes en la microbiota intestinal, por tal razón se ha descrito que Escherichia coli es una de las principales Enterobacterias involucradas en las manifestaciones clínicas presentes en pacientes con infecciones del tracto urinario. Las cepas de E. coli han sido clasificadas inicialmente en 4 grupos filogenéticos según Clermont y col. (2000, de este modo se conocen “cepas intestinales comensales, pertenecientes a los grupos A y B1, y cepas extra intestinales virulentas asociadas a los grupos B2 y D, para llevar a cabo dicha clasificación Clermont, diseñó herramientas moleculares como la PCR-triple, mediante la utilización de diferentes genes tales como ChuA, yjaA y TSPE4.C2”. Sin embargo debido a la complejidad estructural genética de este microorganismo, se han logrado establecer nuevos grupos filogenéticos de E. coli, A, B1, B2, C, D, E, F y un último grupo el cual no ha sido completamente identificado, por tal razón es importante conocer cuáles son los grupos filogenéticos que están presentes en nuestra región, mediante el uso de técnicas moleculares que permitan realizar la caracterización filogenética de dicho microorganismo y de esta manera lograr establecer los perfiles de resistencia y evaluar los posibles factores de virulencia asociados al proceso de infección. Objetivo: Realizar la caracterización molecular de los grupos filogenéticos de E. coli uropatógena aislada de pacientes ambulatorios que asisten a un laboratorio de tercer nivel de complejidad de la ciudad de Bucaramanga mediante el uso de PCR-multiplex. Materiales y métodos: El cálculo del tamaño muestral se realizó teniendo en cuenta la prevalencia reportada por Orduz, K y Trejos, J, (2010, se calculó el tamaño de muestra

  15. Tetracycline and oxytetracycline resistance determinants detected in Bacillus cereus strains isolated from honey samples Detección de determinantes de resistencia a tetraciclina y oxitetraciclina en cepas de Bacillus cereus aisladas de muestras de miel

    Directory of Open Access Journals (Sweden)

    A. C. López

    2008-12-01

    oxitetraciclina en las poblaciones de Bacillus cereus presentes en la miel. De un total de 77 aislamientos evaluados, 30 (39% resultaron resistentes a tetraciclina y/o minociclina de acuerdo con los resultados de las pruebas de difusión en disco. Dentro del grupo que presentó un fenotipo resistente, se investigó la presencia de los determinantes tetK, tetL, tetM, tetO, tetW, otrA y otrB por PCR y se determinaron los valores de CIM para tetraciclina, oxitetraciclina y minociclina. De acuerdo con los resultados obtenidos por PCR, 23 aislamientos (77% presentaron al menos un determinante de resistencia a tetraciclina o a oxitetraciclina; el genotipo tetK se encontró en 10 de esos aislamientos, mientras que los genotipos tetL, tetM y otrA se hallaron en 3, 2 y 5 aislamientos, respectivamente. Ningún aislamiento presentó los genotipos tetW, tetO ni otrB. Adicionalmente, se encontraron los genotipos tetK plus tetM (2 aislamientos; tetK plus tetL (1 aislamiento y tetK plus otrA (1 aislamiento. Por otra parte, 7 cepas (23% resultaron resistentes a tetraciclina, oxitetraciclina y/o minociclina por CIM, pero no presentaban ninguno de los determinantes tet u otr estudiados. Estos resultados indican la existencia de un alto porcentaje de cepas de B. cereus aisladas de miel con genes de resistencia a tetraciclina y oxitetraciclina, incluyendo los determinantes tetK, tetL, tetM y otrA. Este estudio constituye el primer registro de la presencia del determinante tetK de resistencia a tetraciclina en B. cereus, como así también la presencia del determinante otrA dentro del género Bacillus.

  16. Nitrogen-fixing methane-utilizing bacteria

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1976-01-01

    Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

  17. 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…

  18. Current strategies for improving food bacteria

    NARCIS (Netherlands)

    Kuipers, O P; Buist, Girbe; Kok, Jan

    2000-01-01

    Novel concepts and methodologies are emerging that hold great promise for the directed improvement of food-related bacteria, specifically lactic acid bacteria. Also, the battle against food spoilage and pathogenic bacteria can now be fought more effectively. Here we describe recent advances in

  19. Ecology of mycophagous collimonas bacteria in soil

    NARCIS (Netherlands)

    Höppener-Ogawa, Sachie

    2008-01-01

    Bacteria belonging to the genus Collimonas consist of soil bacteria that can grow at expense of living fungal hyphae i.e. they are mycophagous. This PhD studies deals with the ecology of mycophagous bacteria in soil using collimonads as model organisms. Collimonads were found to be widely

  20. AIDS: "it's the bacteria, stupid!".

    Science.gov (United States)

    Broxmeyer, Lawrence; Cantwell, Alan

    2008-11-01

    Acid-fast tuberculous mycobacterial infections are common in AIDS and are regarded as secondary "opportunistic infections." According to the National Institute of Allergy and Infectious Diseases, TB is the major attributable cause of death in AIDS patients. Could such bacteria play a primary or causative role in AIDS? Certainly, In screening tests for HIV, there is frequent, up to 70%, cross-reactivity, between the gag and pol proteins of HIV and patients with mycobacterial infections such as tuberculosis. By 1972, five years before gays started dying in the U.S., Rolland wrote Genital Tuberculosis, a Forgotten Disease? And ironically, in 1979, on the eve of AIDS recognition, Gondzik and Jasiewicz showed that even in the laboratory, genitally infected tubercular male guinea pigs could infect healthy females through their semen by an HIV-compatible ratio of 1 in 6 or 17%, prompting him to warn his patients that not only was tuberculosis a sexually transmitted disease, but also the necessity of the application of suitable contraceptives, such as condoms, to avoid it. Gondzik's solution and date of publication are chilling; his findings significant. Since 1982 Cantwell et al found acid-fast bacteria closely related to tuberculosis (TB) and atypical tuberculosis in AIDS tissue. On the other hand molecular biologist and virologist Duesberg, who originally defined retroviral ultrastructure, has made it clear that HIV is not the cause of AIDS and that the so-called AIDS retrovirus has never been isolated in its pure state. Dr. Etienne de Harven, first to examine retroviruses under the electron, agrees. In 1993 HIV co-discoverer Luc Montagnier reported on cell-wall-deficient (CWD) bacteria which he called "mycoplasma" in AIDS tissue. He suspected these as a necessary "co-factor" for AIDS. Remarkably, Montagnier remained silent on Cantwell's reports of acid-fast bacteria which could simulate "mycoplasma" in AIDS tissue. Mattman makes clear that the differentiation between

  1. Cultivos primarios de células endoteliales aisladas de cordón umbilical humano: un modelo biológico para el estudio de los mecanismos de infección por enterococos.

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Chiriboga

    2004-12-01

    Full Text Available Aunque las especies de enterococos son flora normal del tracto gastrointestinal humano, se encuentran entre los tres agentes patógenos microbianos que más se asocian con infecciones intrahospitalarias. Tradicionalmente, los enterococos se han considerado bacterias extracelulares. Sin embargo, es creciente la información que reporta su ingreso a través de líneas celulares epiteliales o macrófagos. A pesar de que estos microorganismos constituyen el tercer grupo de aislamientos obtenido de pacientes con bacteriemia o endocarditis, su interacción con la célula endotelial no se ha descrito completamente. En el presente trabajo evaluamos si el aislamiento intrahospitalario de Enterococcus faecalis (Ef2880 podía penetrar en células endoteliales de la vena de cordón umbilical humano (HUVEC cultivadas in vitro. Nuestros resultados indican que los cultivos primarios HUVEC después de ser inoculados con Ef2890, incubados y tratados con antibióticos bactericidas para las bacterias extracelulares y adheridas a la cara externa de la membrana celular, exhiben bacterias intracelulares que pueden ser recuperadas vivas cuatro horas después de la inoculación. El modelo biológico desarrollado se puede constituir en una herramienta útil para el estudio de las interacciones que establecen los enterococos con el endotelio.

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

    OpenAIRE

    Denoncourt, Alix M.; 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...

  3. Endocarditis caused by anaerobic bacteria.

    Science.gov (United States)

    Kestler, M; Muñoz, P; Marín, M; Goenaga, M A; Idígoras Viedma, P; de Alarcón, A; Lepe, J A; Sousa Regueiro, D; Bravo-Ferrer, J M; Pajarón, M; Costas, C; García-López, M V; Hidalgo-Tenorio, C; Moreno, M; Bouza, E

    2017-10-01

    Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES). We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria). Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%). IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. 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. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. Antibiotic- and heavy-metal resistance in bacteria isolated from deep subsurface in El Callao region, Venezuela

    Directory of Open Access Journals (Sweden)

    Maura Lina Rojas Pirela

    2014-07-01

    Full Text Available Título en ingles: Antibiotic- and heavy-metal resistance in bacteria isolated from deep subsurface in El Callao region, Venezuela Título corto: Antibiotic and metal resistance in bacteria from deep subsurface Título en español: Resistencia a antibioticos y metals pesados en bacterias aisladas de subsuelo en la región El Callao, Venezuela Resumen:  Se investigó el efecto de la contaminación con mercurio (Hg en las comunidades bacterianas del subsuelo profundo en la región de El Callao (Estado Bolívar, Venezuela. Se estudiaron comunidades bacterianas de dos niveles de profundidad (-288 m y -388 m en una mina de oro con el propósito de describir las características más relevantes de las bacterias indígenas cultivables que colonizaban esta mina. Se evaluaron los patrones de resistencia a antibióticos y metales pesados, presencia del gen merA y plásmidos en aislados resistentes. Se encontró una elevada frecuencia de bacterias indígenas resistentes al Hg y otros metales pesados. De 76 aislados Hg-resistentes probados 73.7 % fueron adicionalmente resistentes a ampicilina; 86.8 % a cloranfenicol; 67.1 % a tetraciclina; 56.6 % a estreptomicina y 51.3 % a kanamicina. Además, se encontró que 40.74 % (-328 m y 26.53 % (-388 m de las bacterias Hg-resistentes fueron simultáneamente resistentes tanto a cuatro como a cinco de estos antibióticos. Se detectó la presencia de plásmidos de alto y bajo peso molecular y, a pesar de que los aislados mostraban resistencia a compuestos mercuriales, la presencia del gen merA fue detectada solo en 71.05 % de los cepas. Estos resultados sugieren que la exposición a Hg podría ser una presión selectiva en la proliferación de bacterias resistentes a antibióticos y promover el mantenimiento y propagación de estos genes de resistencia. Sin embargo, la existencia de tales resistencias a estas profundidades podría también apoyar la idea de que la resistencia a antibióticos en estas bacterias es

  6. Pathogenic mechanisms of intracellular bacteria.

    Science.gov (United States)

    Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

    2017-06-01

    We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

  7. Money and transmission of bacteria.

    Science.gov (United States)

    Gedik, Habip; Voss, Timothy A; Voss, Andreas

    2013-08-28

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, the Leu was the only banknote to yield VRE after one day of drying. Other currencies either enabled the survival of Extended-Spectrum Beta-Lactamases (ESBL) and VRE (e.g. Euro), but not of MRSA, or the other way round (e.g. US Dollar). While a variety of factors such as community hygiene levels, people's behaviour, and antimicrobial resistance rates at community level obviously have influence on the transmission of resistant microorganisms, the type of banknote-paper may be an additional variable to consider.

  8. Resistance of Bacteria to Biocides.

    Science.gov (United States)

    Maillard, Jean-Yves

    2018-04-01

    Biocides and formulated biocides are used worldwide for an increasing number of applications despite tightening regulations in Europe and in the United States. One concern is that such intense usage of biocides could lead to increased bacterial resistance to a product and cross-resistance to unrelated antimicrobials including chemotherapeutic antibiotics. Evidence to justify such a concern comes mostly from the use of health care-relevant bacterial isolates, although the number of studies of the resistance characteristics of veterinary isolates to biocides have increased the past few years. One problem remains the definition of "resistance" and how to measure resistance to a biocide. This has yet to be addressed globally, although the measurement of resistance is becoming more pressing, with regulators both in Europe and in the United States demanding that manufacturers provide evidence that their biocidal products will not impact on bacterial resistance. Alongside in vitro evidence of potential antimicrobial cross-resistance following biocide exposure, our understanding of the mechanisms of bacterial resistance and, more recently, our understanding of the effect of biocides to induce a mechanism(s) of resistance in bacteria has improved. This article aims to provide an understanding of the development of antimicrobial resistance in bacteria following a biocide exposure. The sections provide evidence of the occurrence of bacterial resistance and its mechanisms of action and debate how to measure bacterial resistance to biocides. Examples pertinent to the veterinary field are used where appropriate.

  9. Differential scanning calorimetry of bacteria.

    Science.gov (United States)

    Miles, C A; Mackey, B M; Parsons, S E

    1986-04-01

    Thermograms obtained by differential scanning calorimetry of a range of bacteria of different heat resistances were compared. Equations were derived to calculate the rate at which the numbers of viable organisms in a calorimeter decline as the temperature is raised at a constant rate. Vegetative bacteria scanned at 10 degrees C min-1 showed multi-peaked thermograms with four major peaks (denoted m, n, p and q) occurring in the regions 68-73, 77-84, 89-99 and 105-110 degrees C respectively. Exceptions were that peak m (the largest peak) occurred at 79-82 degrees C in Bacillus stearothermophilus and an additional peak, r, was detected in Escherichia coli at 119 degrees C. At temperatures below the main peak m there were major differences in thermograms between species. There was a direct relationship between the onset of thermal denaturation and the thermoresistance of different organisms. Heat-sensitive organisms displayed thermogram features which were absent in the more heat-resistant types. When samples were cooled to 5 degrees C and re-heated, a small endothermic peak, pr, was observed at the same temperature as p. Peaks p and pr were identified as the melting endotherms of DNA. In all vegetative organisms examined, maximum death rates, computed from published D and z values, occurred at temperatures above the onset of thermal denaturation, i.e. cell death and irreversible denaturation of cell components occurred within the same temperature range.

  10. Effect of D-004, a lipid extract from royal palm (Roystonea regia fruits, on phenylephrine-induced contractions of isolated rat prostate Efecto de D-004, un extracto lipídico extraído de las frutas de la palma real (Roystonea regia sobre las contracciones provocadas por la Fenilefrina sobre la próstata aislada de rata

    Directory of Open Access Journals (Sweden)

    Lourdes Arruzazabala Valmaña

    2009-12-01

    Full Text Available D-004, un extracto lipídico de las frutas de Roystonea regia, inhibe la contracción provocada por la norepinefrina en el vas deferens de las ratas. No obstante, el efecto de D-004 sobre las respuestas contráctiles adrenérgicas a1 en las preparaciones aisladas de la próstata no ha sido estudiado. Por lo tanto, este estudio investigó los efectos de D-004 sobre las contracciones provocadas por la fenilefrina en las extracciones aisladas de la próstata de la rata. D-004 (125-500 mg/mL fue adicionado a las preparaciones a partir de la próstata en la que las contracciones fueron provocadas por la fenilefrina (10-6-10-4 M o por CIK (50 mM. D-004 (250-500 mg/mL en forma significativa y la dosis en forma dependiente inhibieron las contracciones provocadas por la fenilefrina mediante un mecanismo no competetitivo, reduciendo así (12-60 % la contracción máxima por la fenilefrina con respecto a las preparaciones controles. D-004 a 500 µg/mL inhibieron de la misma forma tanto CIK como las respuestas contráctiles-fenilefrina. Tamsulosin (0,01 mg/mL eliminó la acción de la fenilefrina (100 % de inhibición, pero no afectó las contracciones provocadas por CIK.D-004, a lipid extract of Roystonea regia fruits, inhibits norepinephrine-elicited contraction in rat vas deferens. Nevertheless, the effect of D-004 on a1-adrenergic contractile responses in isolated prostate preparations had not been studied. Therefore, this study investigated the effects of D-004 on phenylephrine-induced contractions in isolated rat prostate strips. D-004 (125-500 mg/mL was added to prostate preparations in which contractions were induced with phenylephrine (10-6-10-4 M or with ClK (50 mM. D-004 (250-500 mg/mL significantly (p < 0,01.and dose-dependently inhibited the phenylephrine-induced contractions through a non-competitive mechanism, since it reduced (12-60 % the maximal contraction to phenyle phrine with respect to control preparations. D-004 at 500 mg/mL inhibited

  11. Efecto de bacterias probióticas en el cultivo larvario del ostión de placer Crassostrea corteziensis (Bivalvia: Ostreidae

    Directory of Open Access Journals (Sweden)

    Angel Isidro Campa-Córdova

    2011-03-01

    Full Text Available El ostión de placer u ostra del Cortés (Crassostrea corteziensis se considera como una especie con potencial para ser cultivada en gran escala. Sin embargo, al igual que en otros bivalvos, la alta mortalidad que se presenta durante la etapa larvaria y juvenil, es el principal problema que limita el desarrollo del cultivo en el laboratorio. Un método que está ganando aceptación en la acuicultura es el uso de bacterias probióticas para controlar patógenos microbianos. Este estudio analiza el efecto de estas bacterias en la supervivencia y talla final de larvas de ostión de placer Crassostrea corteziensis. Se utilizó una cepa de bacterias ácido lácticas (cepa NS61 aisladas N. subnodosus, así como de bacilos aislados de L. vannamei (Pseudomonas aeruginosa, cepa YC58 y de C. corteziensis (Burkholderia cepacia, cepa Y021. Las cepas se evaluaron por inmersión en cultivos larvarios de C. corteziensis a dos concentraciones diferentes, hasta completar el estadio pediveliger. Los organismos se trataron con bacterias ácido lácticas (Lb, una mezcla de bacilos (Lb en proporción 1:1 y un grupo control. La concentración de 1x10(4UFC/ml registró una mayor supervivencia con Lb y Mb respecto al grupo control. La supervivencia con Mb a una concentración de 1x10(5UFC/ml fue mayor que la del grupo control y del grupo tratado con Lb. Los resultados mostraron que las larvas de C. corteziensis tratadas con probióticos no incrementaron significativamente su talla respecto a las larvas del grupo control. Mientras que las tratadas con Lb a la concentración mayor, 1x10(5UFC/ml, mostraron una disminución de la supervivencia respecto a las tratadas con 1x10(4UFC/ml. Este estudio demostró el efecto benéfico de cepas probióticas utilizadas individualmente o en mezcla en el cultivo larvario de C. corteziensis.Effect of probiotic bacteria on survival and growth of Cortez oyster larvae, Crassostrea corteziensis (Bivalvia: Ostreidae. Disease control

  12. RESISTENCIA A LOS ANTIBIÓTICOS EN CEPAS DE KLEBSIELLA PNEUMONIAE, SERRATIA SPP. Y ACINETOBACTER SPP.AISLADAS DE PACIENTES CON INFECCIÓN DEL TRACTO URINARIO - LIMA, PERU

    Directory of Open Access Journals (Sweden)

    Luján Roca DA

    2013-01-01

    Full Text Available INFECTION - LIMA, PERU Introduction: Urinary tract infection (UTI is one of the most common infections in clinical practice. Gram negative bacteria as Klebsiella pneumoniae, Serratia spp. and Acinetobacter spp. can cause UTI. Objective: To study antibiotic resistance in K. pneumoniae, Serratia spp. and Acinetobacter spp. strains isolated from UTI Material and methods: Urine cultures were collected from January 2003 to December 2003. Identification of isolated bacteria included biochemical characteristics. Bauer-Kirby disc diffusion test was performed. Results: A total of 106 strains were evaluated (41 of K. pneumoniae, 28 of Serratia spp. and 37 of Acinetobacter spp.. Among K. pneumoniae isolates resistance to ampicillin (83% was remarkable. The Serratia spp. isolates displayed a high level of resistance to nalidixic acid (79% and gentamicin (75%. In Acinetobacter spp. isolates high resistance rates were observed against amikacin (81%, gentamicin (67% and trimethoprim/sulfamethoxazole(71%. Conclusions: In general, antibiotic resistance patterns were high. Acinetobacter spp. showed elevated resistance rates (>50% against antibiotics included.

  13. 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...

  14. Bactericide for sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Shklyar, T F; Anoshina, G M; Blokhin, V Ye; Kisarrev, Ye L; Novikovsa, G M

    1981-01-01

    The aim of the invention is to find a bactericide for sulfate-reducing bacteria of oil fields in Western Siberia in order to suppress the biocorrosive activity on oil industry equipment. This goal is achieved by using M-nitroacetanylide as the bactericide of sulfate-reducing bacteria. This agent suppresses the activity of a stored culture of sulfate-reducing bacteria that comes from industrial waste waters injection wells of the Smotlor oil field.

  15. Differential staining of bacteria: acid fast stain.

    Science.gov (United States)

    Reynolds, Jackie; Moyes, Rita B; Breakwell, Donald P

    2009-11-01

    Acid-fastness is an uncommon characteristic shared by the genera Mycobacterium (Section 10A) and Nocardia. Because of this feature, this stain is extremely helpful in identification of these bacteria. Although Gram positive, acid-fast bacteria do not take the crystal violet into the wall well, appearing very light purple rather than the deep purple of normal Gram-positive bacteria. (c) 2009 by John Wiley & Sons, Inc.

  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. Magnetotactic bacteria at the geomagnetic equator

    International Nuclear Information System (INIS)

    Frankel, R.B.; Blakemore, R.P.; Araujo, F.F.T. de; Esquivel, D.M.S.; Danon, J.

    1981-01-01

    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) [pt

  18. Bioenergetics of photoheterotrophic bacteria in the oceans.

    Science.gov (United States)

    Kirchman, David L; Hanson, Thomas E

    2013-04-01

    Photoheterotrophic microbes, such as proteorhodopsin (PR)-based phototrophic (PRP) and aerobic anoxygenic phototrophic (AAP) bacteria, are well known to be abundant in the oceans, potentially playing unique roles in biogeochemical cycles. However, the contribution of phototrophy to the energy requirements of these bacteria has not been quantitatively examined to date. To better understand the implications of photoheterophy in the oceans, we calculated energy benefits and costs of phototrophy and compared net benefits with maintenance costs. Benefits depend on the number of photosynthetic units (PSUs), absorption cross-section area of each PSU as function of wavelength, the in situ light quality, and the energy yield per absorbed photon. For costs we considered the energy required for the synthesis of pigments, amino acids and proteins in each PSU. Our calculations indicate that AAP bacteria harvest more light energy than do PRP bacteria, but the costs of phototrophy are much higher for AAP bacteria. Still, the net energy gained by AAP bacteria is often sufficient to meet maintenance costs, while that is not the case for PRP bacteria except with high light intensities and large numbers of proteorhodopsin molecules per cell. The low costs and simplicity of PR-based phototrophy explain the high abundance of proteorhodopsin genes in the oceans. However, even for AAP bacteria, the net energy yield of phototrophy is apparently too low to influence the distribution of photoheterotrophic bacteria among various marine systems. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  19. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Høiby, N.

    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...

  20. Isolation and characterization of methanogenic bacteria from ...

    African Journals Online (AJOL)

    Isolation and characterization of methanogenic bacteria from brewery wastewater in Kenya. Sylvia Injete Murunga, Duncan Onyango Mbuge, Ayub Njoroge Gitau, Urbanus Ndungwa Mutwiwa, Ingrid Namae Wekesa ...

  1. Fewer bacteria in warm water

    International Nuclear Information System (INIS)

    Bagh, Lene

    1999-01-01

    There has been many suggestions to how the ideal warm water system should be. Particularly whether warm water containers or heat exchangers in larger houses are the best solutions in order to maintain a water quality with low levels of bacteria. In an investigation made by Statens Byggeforskningsinstitutt (Denmark) regarding ''Bacterial growth in warm water installations with heat exchangers'' there were used several heat exchangers made by Gjelsted and Lund of three of which had HWAT heating cables. The bacterial content was low from these exchangers compared to exchangers with circulation. The article presents promising results from a study where the method was investigated over a longer period in two new larger warm water systems. Some energy conservation aspects are discussed

  2. Modeling Political Populations with Bacteria

    Science.gov (United States)

    Cleveland, Chris; Liao, David

    2011-03-01

    Results from lattice-based simulations of micro-environments with heterogeneous nutrient resources reveal that competition between wild-type and GASP rpoS819 strains of E. Coli offers mutual benefit, particularly in nutrient deprived regions. Our computational model spatially maps bacteria populations and energy sources onto a set of 3D lattices that collectively resemble the topology of North America. By implementing Wright-Fishcer re- production into a probabilistic leap-frog scheme, we observe populations of wild-type and GASP rpoS819 cells compete for resources and, yet, aid each other's long term survival. The connection to how spatial political ideologies map in a similar way is discussed.

  3. 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.

  4. Antioxidant Properties of Probiotic Bacteria.

    Science.gov (United States)

    Wang, Yang; Wu, Yanping; Wang, Yuanyuan; Xu, Han; Mei, Xiaoqiang; Yu, Dongyou; Wang, Yibing; Li, Weifen

    2017-05-19

    Oxidative stress defines a condition in which the prooxidant-antioxidant balance in the cell is disturbed, resulting in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells' viability. Probiotics have been known for many beneficial health effects, and the consumption of probiotics alone or in food shows that strain-specific probiotics can present antioxidant activity and reduce damages caused by oxidation. However, the oxidation-resistant ability of probiotics, especially the underling mechanisms, is not properly understood. In this view, there is interest to figure out the antioxidant property of probiotics and summarize the mode of action of probiotic bacteria in antioxidation. Therefore, in the present paper, the antioxidant mechanisms of probiotics have been reviewed in terms of their ability to improve the antioxidant system and their ability to decrease radical generation. Since in recent years, oxidative stress has been associated with an altered gut microbiota, the effects of probiotics on intestinal flora composition are also elaborated.

  5. Sterol Synthesis in Diverse Bacteria.

    Science.gov (United States)

    Wei, Jeremy H; Yin, Xinchi; Welander, Paula V

    2016-01-01

    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 five 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. Some bacteria

  6. Characterization of Bacteria Isolation of Bacteria from Pinyon Rhizosphere,

    Science.gov (United States)

    2016-01-01

    Two hundred and fifty bacterial strains were isolated from pinyon rhizosphere and screened for biosurfactants production. Among them, six bacterial strains were selected for their potential to produce biosurfactants using two low cost wastes, crude glycerol and lactoserum, as raw material. Both wastes were useful for producing biosurfactants because of their high content in fat and carbohydrates. The six strains were identified by 16S rDNA with an identity percentage higher than 95%, three strains belonged to Enterobacter sp., Pseudomonas aeruginosa, Bacillus pumilus and Rhizobium sp. All strains assayed were able to grow and showed halos around the colonies as evidence of biosurfactants production on Cetyl Trimethyl Ammonium Bromide agar with crude glycerol and lactoserum as substrate. In a mineral salt liquid medium enriched with both wastes, the biosurfactants were produced and collected from free cell medium after 72 h incubation. The biosurfactants produced reduced the surface tension from 69 to 30 mN/m with an emulsification index of diesel at approximately 60%. The results suggest that biosurfactants produced by rhizosphere bacteria from pinyon have promising environmental applications.

  7. Characterization of (per)chlorate-reducing bacteria

    NARCIS (Netherlands)

    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

  8. 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...

  9. Rock-degrading endophytic bacteria in cacti

    Science.gov (United States)

    M. Esther Puente; Ching Y. Li; Yoav Bashan

    2009-01-01

    A plant-bacterium association of the cardon cactus (Pachycereus pringlei) and endophytic bacteria promotes establishment of seedlings and growth on igneous rocks without soil. These bacteria weather several rock types and minerals, unbind significant amounts of useful minerals for plants from the rocks, fix in vitro N2. produce...

  10. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C; Tümmler, B

    2010-01-01

    Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole...... weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment....

  11. Analyzing Arthropods for the Presence of Bacteria

    OpenAIRE

    Andrews, Elizabeth S.

    2013-01-01

    Bacteria within arthropods can be identified using culture-independent methods. This unit describes protocols for surface sterilization of arthropods, DNA extraction of whole bodies and tissues, touchdown PCR amplification using 16S rDNA general bacteria primers and profiling the bacterial community using denaturing gradient gel electrophoresis.

  12. Resuscitation effects of catalase on airborne bacteria.

    OpenAIRE

    Marthi, B; Shaffer, B T; Lighthart, B; Ganio, L

    1991-01-01

    Catalase incorporation into enumeration media caused a significant increase (greater than 63%) in the colony-forming abilities of airborne bacteria. Incubation for 30 to 60 min of airborne bacteria in collection fluid containing catalase caused a greater than 95% increase in colony-forming ability. However, catalase did not have any effects on enumeration at high relative humidities (80 to 90%).

  13. Catabolism of lysine by mixed rumen bacteria

    International Nuclear Information System (INIS)

    Onodera, Ryoji; Kandatsu, Makoto.

    1975-01-01

    Metabolites arising from the catabolism of lysine by the mixed rumen bacteria were chromatographically examined by using radioactive lysine. After 6 hr incubation, 241 nmole/ml of lysine was decomposed to give ether-soluble substances and CO 2 by the bacteria and 90 nmole/ml of lysine was incorporated unchanged into the bacteria. delta-Aminovalerate, cadaverine or pipecolate did not seem to be produced from lysine even after incubation of the bacteria with addition of those three amino compounds to trap besides lysine and radioactive lysine. Most of the ether-soluble substances produced from radioactive lysine was volatile fatty acids (VFAs). Fractionation of VFAs revealed that the peaks of butyric and acetic acids coincided with the strong radioactive peaks. Small amounts of radioactivities were detected in propionic acid peak and a peak assumed to be caproic acid. The rumen bacteria appeared to decompose much larger amounts of lysine than the rumen ciliate protozoa did. (auth.)

  14. Biodiversity of Bacteria Isolated from Different Soils

    Directory of Open Access Journals (Sweden)

    Fatma YAMAN

    2017-01-01

    Full Text Available The aim of this study was to determine the biodiversity of PHB producing bacteria isolated from soils where fruit and vegetable are cultivated (onion, grape, olive, mulberry and plum in Aydın providence. Morphological, cultural, biochemical, and molecular methods were used for bacteria identification. These isolated bacteria were identified by 16S rRNA sequencing and using BLAST. The following bacteria Bacillus thuringiensis (6, Bacillus cereus (8, Bacillus anthrachis (1, Bacillus circulans (1, Bacillus weihenstephanensis (1, Pseudomonas putida (1, Azotobacter chroococcum (1, Brevibacterium frigoritolerans (1, Burkholderia sp. (1, Staphylococcus epidermidis (1, Streptomyces exfoliatus (1, Variovorax paradoxus (1 were found. The Maximum Likelihood method was used to produce a molecular phylogenetic analysis and a phylogenetic tree was constructed. These bacteria can produce polyhydroxybutyrate (PHB which is an organic polymer with commercial potential as a biodegradable thermoplastic. PHB can be used instead of petrol derivated non-degradable plastics. For this reason, PHB producing microorganisms are substantial in industry.

  15. 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.

  16. 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...

  17. Hyphae colonizing bacteria associated with Penicillium bilaii

    DEFF Research Database (Denmark)

    Ghodsalavi, Behnoushsadat

    shown that mycorrhizal helper bacteria presenting in mycorrhizal fungi could stimulate fungal growth, promote establishment of root-fungus symbiosis and enhance plant production. But it is unknown if the comparable relationship exist between the non-mycorrhizal fungus P. bilaii and its hyphae associated...... bacteria. In the current PhD thesis, we assumed that hyphae-associated microbiome of P. bilaii might harbor helper bacteria with ability to improve fungal growth and P solubilization performance. Therefore, we aimed to isolate bacteria associated with the P. bilaii hyphae and identify the fungal growth...... stimulating bacteria with the perspective of promoting efficiency of Jumpstart in soil – plant system. For this purpose, most of the work within the current project was carried out by development of suitable model systems by mimicking the natural soil habitat to reach to the reliable performance in soil...

  18. [Unique properties of highly radioresistant bacteria].

    Science.gov (United States)

    Romanovskaia, V A; Rokitko, P V; Malashenko, Iu R

    2000-01-01

    In connection with the Chernobyl Nuclear Power Plant (ChNPP) accident and the negative ecological after-effects for biota in this zone the interest has arisen to radioresistant bacteria, as to the most dynamic model of the given ecosystem, and to mechanisms which provide resistance of bacteria to ionizing radiation. The analysis of published data has shown that the radioresistant bacteria are not interrelated taxonomically and phylogenetically. The extreme radioresistant bacteria are represented by the Deinococcus species, which form a group phylogenetically close to the line Thermus-Meiothermus. Other radioresistant bacteria are the representatives of the genera Rubrobacter, Methylobacterium, Kocuria, Bacillus and some archebacteria. Data on natural habitats, of radioresistant bacteria are not numerous. In a number of cases it is difficult to distinguish their natural habitats, as they were isolated from the samples which were previously exposed to X-ray or gamma-irradiation, or from the ecosystems with the naturally raised radioactivity. To understand the strategy of survival of radioresistant bacteria, we briefly reviewed the mechanism of action of various species of radiation on cells and macromolecules; physiological signs of the cell damage caused by radiation; mechanisms eliminating (repairing) these damages. More details on mechanisms of the DNA repair in D. radiodurans are described. The extreme resistance of D. radiodurans to the DNA damaging factors is defined by 1) repair mechanisms which fundamentally differ from those in other procaryotes; 2) ability to increase the efficiency of a standard set of the DNA repairing proteins. Literary and own data on the effect of radiation on survival of various groups of bacteria in natural ecosystems are summarized. The ecological consequences of the ChNPP accident for soil bacteria in this region were estimated. The reduction of the number of soil bacteria and recession of microbial diversity under the effect of

  19. Comparative cytotoxicity of periodontal bacteria

    International Nuclear Information System (INIS)

    Stevens, R.H.; Hammond, B.F.

    1988-01-01

    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

  20. Tape Cassette Bacteria Detection System

    Science.gov (United States)

    1973-01-01

    The design, fabrication, and testing of an automatic bacteria detection system with a zero-g capability and based on the filter-capsule approach is described. This system is intended for monitoring the sterility of regenerated water in a spacecraft. The principle of detection is based on measuring the increase in chemiluminescence produced by the action of bacterial porphyrins (i.e., catalase, cytochromes, etc.) on a luminol-hydrogen peroxide mixture. Since viable as well as nonviable organisms initiate this luminescence, viable organisms are detected by comparing the signal of an incubated water sample with an unincubated control. Higher signals for the former indicate the presence of viable organisms. System features include disposable sealed sterile capsules, each containing a filter membrane, for processing discrete water samples and a tape transport for moving these capsules through a processing sequence which involves sample concentration, nutrient addition, incubation, a 4 Molar Urea wash and reaction with luminol-hydrogen peroxide in front of a photomultiplier tube. Liquids are introduced by means of a syringe needle which pierces a rubber septum contained in the wall of the capsule. Detection thresholds obtained with this unit towards E. coli and S. marcescens assuming a 400 ml water sample are indicated.

  1. Antioxidant Properties of Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2017-05-01

    Full Text Available Oxidative stress defines a condition in which the prooxidant–antioxidant balance in the cell is disturbed, resulting in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells’ viability. Probiotics have been known for many beneficial health effects, and the consumption of probiotics alone or in food shows that strain-specific probiotics can present antioxidant activity and reduce damages caused by oxidation. However, the oxidation-resistant ability of probiotics, especially the underling mechanisms, is not properly understood. In this view, there is interest to figure out the antioxidant property of probiotics and summarize the mode of action of probiotic bacteria in antioxidation. Therefore, in the present paper, the antioxidant mechanisms of probiotics have been reviewed in terms of their ability to improve the antioxidant system and their ability to decrease radical generation. Since in recent years, oxidative stress has been associated with an altered gut microbiota, the effects of probiotics on intestinal flora composition are also elaborated.

  2. Sensibilidad antimicrobiana y caracterización de cepas de Streptococcus pyogenes aisladas de un brote de escarlatina Antimicrobial sensitivity and typing of Streptococcus pyogenes strains isolated during a scarlet fever outbreak

    Directory of Open Access Journals (Sweden)

    Alberto González Pedraza-Avilés

    2002-09-01

    Full Text Available Objetivo. Evaluar la actividad in vitro de 13 antibióticos contra 47 Streptococcus pyogenes grupo A (SGA. Determinar la presencia de genes que codifican para exotoxina pirogénica estreptocóccica A (SpeA y serotipos con base en proteína M. Material y métodos. Estudio transversal hecho en el Centro de Salud Dr. José Castro Villagrana sobre un brote de escarlatina en el Colegio Espíritu de América, entre diciembre de 1999 y enero de 2000. El número de niños estudiados fue 137. Se extrajeron porcentajes de sensibilidad. La concentración inhibitoria mínima (CIM se obtuvo por microdilución semiautomatizada. Se utilizó un secuenciador automatizado de DNA para el análisis de variación de secuencias en los genes que codifican para proteína M y SpeA. Resultados. Todas las cepas fueron sensibles a beta-lactámicos y clindamicina; 12.7% fueron resistentes a eritromicina. El serotipo M2 fue el más frecuente, 27 del total. Prácticamente todas las bacterias (96% con el gen SpeA tienen el gen que codifica para el serotipo M2. Conclusiones. Debido a la reciente reaparición de infecciones por SGA se sugiere realizar estudios tanto de sensibilidad a macrólidos y beta-lactámicos, como de epidemiología molecular.Objective. To evaluate the in vitro activities of 13 antimicrobial agents against 47 group A Streptococcus pyogenes (GAS strains, and to determine the presence of genes encoding streptococcal pyrogenic exotoxin A (SpeA and the M--protein serotypes. Materials and Methods. A cross-sectional study was conducted at Centro de Salud Dr. José Castro Villagrana, during a scarlet fever outbreak occurring between December 1999 and January 2000, among 137 children at Colegio Espíritu de América. Minimum Inhibitory Concentrations (MICs were obtained by the semiautomated microdilution method. Automated DNA sequencing was used for analysis of sequence variation in genes encoding the M protein, and SpeA. Results. All strains were sensitive to

  3. 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.

  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. 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.

  6. 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.

  7. Fermentative Bacteria Influence the Competition between Denitrifiers and DNRA Bacteria

    Directory of Open Access Journals (Sweden)

    Eveline M. van den Berg

    2017-09-01

    results of this study clearly show that not only the ratio of available substrates, but also the nature of the electron donor influences the outcome of competition between DNRA and denitrification. Apparently, fermentative bacteria are competitive for the electron donor and thereby alter the ratio of available substrates for nitrate reduction.

  8. 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....

  9. Labelling of bacteria with indium chelates

    International Nuclear Information System (INIS)

    Kleinert, P.; Pfister, W.; Endert, G.; Sproessig, M.

    1985-01-01

    The indium chelates were prepared by reaction of radioactive indiumchloride with 10 μg oxine, 15 μg tropolone and 3 mg acetylacetone, resp. The formed chelates have been incubated with 10 9 germs/ml for 5 minutes, with labelling outputs from 90 to 95%. Both gram-positive (Streptococcus, Staphylococcus) and gram-negative bacteria (Escherichia coli) can be labelled. The reproductive capacity of the bacteria was not impaired. The application of indium labelled bacteria allows to show the distribution of microorganisms within the living organism and to investigate problems of bacterial adherence. (author)

  10. Mortality of fecal bacteria in seawater

    International Nuclear Information System (INIS)

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

    1991-01-01

    The authors 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 trichloracetic acid-insoluble fraction in water samples to which [ 3 H]thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, they found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate

  11. Pu sorption to activated conglomerate anaerobic bacteria

    International Nuclear Information System (INIS)

    Sasaki, Takayuki; Kudo, Akira

    2001-01-01

    The sorption of Pu to the anaerobic bacteria activated under specific conditions of temperature, pH and depleted nutrients after long dormant period was investigated. After 4 h at neutral pH, the distribution coefficient (K d ) between bacteria and aqueous phase at 308 and 278 K had around 10 3 to 10 4 . After over 5 days, however, the K d at only 308 K had increased to over 10 5 . Sterilized (dead) and dormant anaerobic bacteria adsorbed Pu to the same extent. (author)

  12. Bacteria Culture Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/bacteriaculturetest.html Bacteria Culture Test To use the sharing features on this page, please enable JavaScript. What is a Bacteria Culture Test? Bacteria are a large group of ...

  13. Flow cytometry, fluorescent probes, and flashing bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.

    2002-01-01


    Key words: fluorescent probes, flow cytometry, CSLM, viability, survival, microbial physiology, lactic acid bacteria, Lactococcus lactis , Lactobacillus plantarum , cheese, milk,

  14. Effect of leukocyte hydrolases on bacteria

    International Nuclear Information System (INIS)

    Cohen, D.; Michel, J.; Ferne, M.; Bergner-Rabinowitz, S.; Ginsburg, I.

    1979-01-01

    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

  15. Systemic resistance induced by rhizosphere bacteria

    NARCIS (Netherlands)

    Loon, L.C. van; Bakker, P.A.H.M.; Pieterse, C.M.J.

    1998-01-01

    Nonpathogenic rhizobacteria can induce a systemic resistance in plants that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). Rhizobacteria-mediated induced systemic resistance (ISR) has been demonstrated against fungi, bacteria, and viruses in Arabidopsis, bean,

  16. Lactic acid bacteria: microbiological and functional aspects

    National Research Council Canada - National Science Library

    Lahtinen, Sampo

    2012-01-01

    "Updated with the substantial progress made in lactic acid and bacteria research since the third edition, this fourth volume discusses improved insights in genetics and new molecular biological techniques...

  17. 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.

  18. Do bacteria, not fish, produce 'fish kairomone'?

    NARCIS (Netherlands)

    Ringelberg, J.; Van Gool, E.

    1998-01-01

    Fish-associated chemicals enhance phototactic downward swimming in Daphnia. If perch were treated with the antibiotic ampicillin, this enhancement was significantly decreased. Therefore, not fish, but bacteria associated with fish, seem to produce this kairomone. [KEYWORDS: Diel vertical migration;

  19. Bacteria-mediated bisphenol A degradation.

    Science.gov (United States)

    Zhang, Weiwei; Yin, Kun; Chen, Lingxin

    2013-07-01

    Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

  20. Abundance, viability and culturability of Antarctic bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; DeSouza, M.J.B.D.; Nair, S.; Chandramohan, D.

    The viability of total number of bacteria decide the mineralisation rate in any ecosystem and ultimately the fertility of the region. This study aims at establishing the extent of viability in the standing stock of the Antarctic bacterial population...

  1. Interactions between phototrophic bacteria in marine sediments

    NARCIS (Netherlands)

    de Wit, Rutger

    1989-01-01

    Phototrophic bacteria are the most consicious organisms occuring in laminated microbial sediment ecosystems (microbial mats). In the Waddensea area ecosystems consisting of a toplayer of the cyanobacterium Microleus chthonoplastes overlying a red layer of the purple sulfur bacterium Thiocapsa

  2. Molecular genetic studies on obligate anaerobic bacteria

    International Nuclear Information System (INIS)

    Woods, D.R.

    1982-01-01

    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

  3. 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....

  4. Extracellular deoxyribonuclease production by periodontal bacteria.

    Science.gov (United States)

    Palmer, L J; Chapple, I L C; Wright, H J; Roberts, A; Cooper, P R

    2012-08-01

    Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis. © 2011 John Wiley & Sons A/S.

  5. Occurrence of diazotrophic bacteria in Araucaria angustifolia

    OpenAIRE

    Neroni,Rafaela de Fátima; Cardoso,Elke Jurandy Bran Nogueira

    2007-01-01

    Araucaria angustifolia is an environmentally threatened tree and the whole biota of the Araucaria Forest should be investigated with the aim of its preservation. Diazotrophic bacteria are extremely important for the maintenance of ecosystems, but they have never been studied in Araucaria Forests. In this study, diazotrophic bacteria were isolated from Araucaria roots and soil, when grown in semi-specific, semi-solid media. The diazotrophic character of some recovered isolates could be confirm...

  6. [Teichoic acids from lactic acid bacteria].

    Science.gov (United States)

    Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

    2012-01-01

    The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

  7. 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 solidif......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...

  8. Antibiotic-resistant bacteria in drinking water.

    Science.gov (United States)

    Armstrong, J L; Shigeno, D S; Calomiris, J J; Seidler, R J

    1981-08-01

    We analyzed drinking water from seven communities for multiply antibiotic-resistant (MAR) bacteria (bacteria resistant to two or more antibiotics) and screened the MAR bacterial isolates obtained against five antibiotics by replica plating. Overall, 33.9% of 2,653 standard plate count bacteria from treated drinking waters were MAR. Two different raw water supplies for two communities carried MAR standard plate count bacteria at frequencies of 20.4 and 18.6%, whereas 36.7 and 67.8% of the standard plate count populations from sites within the respective distribution systems were MAR. Isolate identification revealed that MAR gram-positive cocci (Staphylococcus) and MAR gram-negative, nonfermentative rods (Pseudomonas, Alcaligenes, Moraxella-like group M, and Acinetobacter) were more common in drinking waters than in untreated source waters. Site-to-site variations in generic types and differences in the incidences of MAR organisms indicated that shedding of MAR bacteria living in pipelines may have contributed to the MAR populations in tap water. We conclude that the treatment of raw water and its subsequent distribution select for standard plate count bacteria exhibiting the MAR phenotype.

  9. Evaluación del potencial probiótico de bacterias ácido lácticas para reducir el colesterol in vitro

    Directory of Open Access Journals (Sweden)

    Clementina Cueto

    2012-01-01

    Full Text Available El co nsumo diario de alimentos probióticos reduce los niveles de colesterol sérico en un 3%, valor significativo para la prevención de la hipercolesterolemia, factor de riesgo de enfermedad cardiovascular y causal de mortalidad. Algunas especies del género Lact obacillus , utilizadas en la industria alimentaria como probiótico, reducen el colesterol sérico por dos mecanismos, la adsorción de colesterol y producción de la enzima hidrolasa de sales biliares. El objetivo del estudio fue evaluar el potencial probiótic o de un grupo de bacterias lácticas aisladas de suero costeño. Se aislaron 53 cepas a partir de nueve muestras de suero costeño; el potencial probiótico de las bacterias se evaluó por tolerancia a pH 2.0, 0.3% de sales biliares y sensibilidad a vancomicina y cefoxitin. Se seleccionaron cinco microorganismos y se identificaron molecularmente, como Lactobacillus fermentum . La capacidad de adsorber el colesterol medida por el método de Kimoto, presentó disminución de 53.06 ± 2.69 μg.mL - 1 para la cepa K73 y 7. 23 ± 2.69 μg.mL - 1 para la cepa K75. Esas mismas cepas mostraron la mayor actividad total y específica de la enzima. Los resultados evidenciaron que no existe relación entre la producción de la enzima y la adsorción del colesterol. La cepa con mayor potenci al probiótico fue K73. La propiedad hipocolesterolémica de Lactobacillus fermentum , podría ser el inicio de la búsqueda de matrices alimentarias que permitan disminuir los niveles del colesterol sérico y adicionen valor agregado al producto.

  10. Nanotextile membranes for bacteria Escherichia coli capturing

    Directory of Open Access Journals (Sweden)

    Jaroslav Lev

    2010-01-01

    Full Text Available The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP. As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

  11. [Spectrum and susceptibility of preoperative conjunctival bacteria].

    Science.gov (United States)

    Fernández-Rubio, M E; Cuesta-Rodríguez, T; Urcelay-Segura, J L; Cortés-Valdés, C

    2013-12-01

    To describe the conjunctival bacterial spectrum of our patients undergoing intraocular surgery and their antibiotic sensitivity during the study period. A retrospective study of preoperative conjunctival culture of patients consecutively scheduled for intraocular surgery from 21 February 2011 to 1 April 2013. Specimens were directly seeded onto blood-agar and MacConkey-agar (aerobiosis incubation, 2 days), and on chocolate-agar (6% CO2 incubation, 7 days). The identified bacteria were divided into 3 groups according to their origin; the bacteria susceptibility tests were performed on those more pathogenic and on some of the less pathogenic when more than 5 colonies were isolated. The sensitivity of the exigent growing bacteria was obtained with disk diffusion technique, and for of the non-exigent bacteria by determining their minimum inhibitory concentration. The Epidat 3.1 program was used for statistical calculations. A total of 13,203 bacteria were identified in 6,051 cultures, with 88.7% being typical colonizers of conjunctiva (group 1), 8.8% typical of airways (group 2), and the remaining 2.5% of undetermined origin (group 3). 530 cultures (8.8%) were sterile. The sensitivity of group 1 was: 99% vancomycin, 95% rifampicin, 87% chloramphenicol, 76% tetracycline. Levels of co-trimoxazole, aminoglycosides, quinolones, β-lactams and macrolides decreased since 2007. The group 2 was very sensitive to chloramphenicol, cefuroxime, rifampicin, ciprofloxacin and amoxicillin/clavulanate. In group 3, to levofloxacin 93%, ciprofloxacin 89%, tobramycin 76%, but ceftazidime 53% and cefuroxime 29% decreased. None of the tested antibiotics could eradicate all possible conjunctival bacteria. Bacteria living permanently on the conjunctiva (group 1) have achieved higher resistance than the eventual colonizers. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  12. Magnetosome chain superstructure in uncultured magnetotactic bacteria

    International Nuclear Information System (INIS)

    Abraçado, Leida G; Farina, Marcos; Abreu, Fernanda; Keim, Carolina N; Lins, Ulysses; Campos, Andrea P C

    2010-01-01

    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. Chemically enhanced sunlight for killing bacteria

    International Nuclear Information System (INIS)

    Block, S.S.; Goswami, D.Y.

    1995-01-01

    Solar ultraviolet (UV) photocatalyzed oxidation of chemicals with titanium dioxide (TiO 2 ) has received considerable attention. Much less recognized, however, is the ability of the same system to destroy bacteria. This study examined this phenomenon and the conditions that affect it. Bacteria in aqueous solution were given solar exposure with titanium dioxide and their survival with time was determined. Lamps with a predominantly solar ultraviolet spectrum were also used in the experiments. Without exposure to UV light, TiO 2 had no deleterious effect on the bacteria. However, several common bacteria on solar exposure in the presence of TiO 2 were killed in just a few minutes, whereas without TiO 2 it took over an hour to destroy them. A concentration of 0.01% TiO 2 was most effective in killing bacteria and 10-fold concentrations lower or higher were successively less effective. Inorganic and organic compounds in solution, even in small amounts, interfered with the efficiency of killing. Alkaline solution also reduced the bactericidal activity. Circulation and agitation provided by stirring to keep the TiO 2 particles suspended reduced the time necessary to kill the bacteria. Time-intensity curves for killing bacteria were the same general shape with or without TiO 2 , indicating that TiO 2 served merely as a catalyst to increase the rate of the reaction but that the mechanism of action was not changed. The shape of the curves show that the organisms are sensitized with a minimum intensity of radiation and that an increase doesn't greatly increase the rate of kill. Below this critical intensity, however, the time required for killing markedly increases as the intensity is decreased

  14. Using Bacteria to Store Renewable Energy (Text Version) | News | NREL

    Science.gov (United States)

    Using Bacteria to Store Renewable Energy (Text Version) Using Bacteria to Store Renewable Energy is a text version of the video entitled "Using Bacteria to Store Renewable Energy." ; Bacteria from some of the Earth's harshest environments now have a new home at NREL. [A natural spring has

  15. Rapid diagnostics of the bacteria in air

    Energy Technology Data Exchange (ETDEWEB)

    Belov Nikolai, N. [ATECH KFT, Budapest (Hungary)

    2000-07-01

    Presence of the bacteria and viruses in the air is great problem now. Terrorists are going to use the bacteria weapon. Now biotechnology provides very cheap equipment ({approx} $500) for modification of the bacteria sorts. It may be used for receiving of new variants of the bacteriological weapon. And presence of one small bacteria aerosol generator in the international airport during several days will start the dangerous epidemic incidence the entire world. From another side - poor countries with hot and wet weather are continuously producing new and new dangerous bacteria. Every year epidemic waves of influence are going from China, India or Africa. And once up a time it will be epidemic explosive with fast lethal finish. Methods of estimation of the bio-aerosols in Air of City are very poor. Standard Bio-aerosol sampler has two conflicting demands. From one side the bio-sampler needs in great air volume of sample with great efficiency of separation of aerosol particles from measured air. From another side all selected particles needs in great care. This demand carried out from method of measurement of bacteria in sample by counting of colonies that grew from bacteria on nutrient media after incubation time. It is a problem to prevent bacterial flora from death during collecting aerosol sample. This time of growth and counting of colony is so long that result of this measurement will be unusable if it will be terrorist action of start of bacteriological was. Here presented new methods for fast diagnostics of the bacteria in the air. It consists from 4 general parts: (1) Micro-droplet method for diagnostics of biological active substances in aerosol sample. This method allows to control the bio-particle position on the plate, to use series of biochemistry species for analytical reaction for this small bio-particle. Small volume of biochemical reaction reduces noise. This method provides extremely high sensitivity for discovering of biological material. (2

  16. Modulation of immune homeostasis by commensal bacteria

    Science.gov (United States)

    Ivanov, Ivaylo I.; Littman, Dan R.

    2011-01-01

    Intestinal bacteria form a resident community that has co-evolved with the mammalian host. In addition to playing important roles in digestion and harvesting energy, commensal bacteria are crucial for the proper functioning of mucosal immune defenses. Most of these functions have been attributed to the presence of large numbers of “innocuous” resident bacteria that dilute or occupy niches for intestinal pathogens or induce innate immune responses that sequester bacteria in the lumen, thus quenching excessive activation of the mucosal immune system. However it has recently become obvious that commensal bacteria are not simply beneficial bystanders, but are important modulators of intestinal immune homeostasis and that the composition of the microbiota is a major factor in pre-determining the type and robustness of mucosal immune responses. Here we review specific examples of individual members of the microbiota that modify innate and adaptive immune responses, and we focus on potential mechanisms by which such species-specific signals are generated and transmitted to the host immune system. PMID:21215684

  17. Molecular analysis of deep subsurface bacteria

    International Nuclear Information System (INIS)

    Jimenez Baez, L.E.

    1989-09-01

    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

  18. Overlapping riboflavin supply pathways in bacteria.

    Science.gov (United States)

    García-Angulo, Víctor Antonio

    2017-03-01

    Riboflavin derivatives are essential cofactors for a myriad of flavoproteins. In bacteria, flavins importance extends beyond their role as intracellular protein cofactors, as secreted flavins are a key metabolite in a variety of physiological processes. Bacteria obtain riboflavin through the endogenous riboflavin biosynthetic pathway (RBP) or by the use of importer proteins. Bacteria frequently encode multiple paralogs of the RBP enzymes and as for other micronutrient supply pathways, biosynthesis and uptake functions largely coexist. It is proposed that bacteria shut down biosynthesis and would rather uptake riboflavin when the vitamin is environmentally available. Recently, the overlap of riboflavin provisioning elements has gained attention and the functions of duplicated paralogs of RBP enzymes started to be addressed. Results point towards the existence of a modular structure in the bacterial riboflavin supply pathways. Such structure uses subsets of RBP genes to supply riboflavin for specific functions. Given the importance of riboflavin in intra and extracellular bacterial physiology, this complex array of riboflavin provision pathways may have developed to contend with the various riboflavin requirements. In riboflavin-prototrophic bacteria, riboflavin transporters could represent a module for riboflavin provision for particular, yet unidentified processes, rather than substituting for the RBP as usually assumed.

  19. Bacteria and plutonium in marine environments

    International Nuclear Information System (INIS)

    Carey, A.E.; Bowen, V.T.

    1978-01-01

    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 237 Pu uptake used a strain of Leucothrix mucor isolated from a macroalga. Enumeration shows bacteria to range 10 4 to 10 5 cells/ml in seawater or 10 7 to 10 8 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 237 Pu 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

  20. 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.

  1. COMPETITION BETWEEN ANOXYGENIC PHOTOTROPHIC BACTERIA AND COLORLESS SULFUR BACTERIA IN A MICROBIAL MAT

    NARCIS (Netherlands)

    VISSCHER, PT; VANDENENDE, FP; SCHAUB, BEM; VANGEMERDEN, H

    The populations of chemolithoautotrophic (colorless) sulfur bacteria and anoxygenic phototrophic bacteria were enumerated in a marine microbial mat. The highest population densities were found in the 0-5 mm layer of the mat: 2.0 X 10(9) cells CM-3 sediment, and 4.0 X 10(7) cells cm-3 sediment for

  2. 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.

  3. Effects of ionizing radiation on bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Suhadi, F [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1976-10-01

    The differences of radiosensitivities among bacteria in addition to the dependence upon the species or strains also depends on the environmental condition during irradiation (temperature, medium, the presence of protective or sensitizing agents, the gas phase or atmosphere, and water activity, or degree of hydration) and on the effects of the environmental condition before and after irradiation treatment (temperature of incubation, age of culture and growth medium). In general, spores are more resistant to radiation than vegetatic bacteria, with the exception that a few cocci are the most radiation resistant bacteria (Micrococcus and Streptococcus). The application of ionizing radiation in the fields of microbiology supports the radiation sterilization of medical and pharmaceutical products. In addition, microbiological aspects of food preservation, especially radurization, radicidation, and immunization studies by using irradiated microorganisms, are also important.

  4. Threats and opportunities of plant pathogenic bacteria.

    Science.gov (United States)

    Tarkowski, Petr; Vereecke, Danny

    2014-01-01

    Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Hydrodynamic interaction between bacteria and passive sphere

    Science.gov (United States)

    Zhang, Bokai; Ding, Yang; Xu, Xinliang

    2017-11-01

    Understanding hydrodynamic interaction between bacteria and passive sphere is important for identifying rheological properties of bacterial and colloidal suspension. Over the past few years, scientists mainly focused on bacterial influences on tracer particle diffusion or hydrodynamic capture of a bacteria around stationary boundary. Here, we use superposition of singularities and regularized method to study changes in bacterial swimming velocity and passive sphere diffusion, simultaneously. On this basis, we present a simple two-bead model that gives a unified interpretation of passive sphere diffusion and bacterial swimming. The model attributes both variation of passive sphere diffusion and changes of speed of bacteria to an effective mobility. Using the effective mobility of bacterial head and tail as an input function, the calculations are consistent with simulation results at a broad range of tracer diameters, incident angles and bacterial shapes.

  6. Interactions among sulfide-oxidizing bacteria

    Science.gov (United States)

    Poplawski, R.

    1985-01-01

    The responses of different phototrophic bacteria in a competitive experimental system are studied, one in which primary factors such as H2S or light limited photometabolism. Two different types of bacteria shared one limited source of sulfide under specific conditions of light. The selection of a purple and a green sulfur bacteria and the cyanobacterium was based on their physiological similarity and also on the fact that they occur together in microbial mats. They all share anoxygenic photosynthesis, and are thus probably part of an evolutionary continuum of phototrophic organisms that runs from, strictly anaerobic physiology to the ability of some cyanobacteria to shift between anoxygenic bacterial style photosynthesis and the oxygenic kind typical of eukaryotes.

  7. Copper tolerance and virulence in bacteria

    Science.gov (United States)

    Ladomersky, Erik; Petris, Michael J.

    2015-01-01

    Copper (Cu) is an essential trace element for all aerobic organisms. It functions as a cofactor in enzymes that catalyze a wide variety of redox reactions due to its ability to cycle between two oxidation states, Cu(I) and Cu(II). This same redox property of copper has the potential to cause toxicity if copper homeostasis is not maintained. Studies suggest that the toxic properties of copper are harnessed by the innate immune system of the host to kill bacteria. To counter such defenses, bacteria rely on copper tolerance genes for virulence within the host. These discoveries suggest bacterial copper intoxication is a component of host nutritional immunity, thus expanding our knowledge of the roles of copper in biology. This review summarizes our current understanding of copper tolerance in bacteria, and the extent to which these pathways contribute to bacterial virulence within the host. PMID:25652326

  8. Lethal photosensitization of biofilm-grown bacteria

    Science.gov (United States)

    Wilson, Michael

    1997-12-01

    Antibacterial agents are increasingly being used for the prophylaxis and treatment of oral diseases. As these agents can be rendered ineffective by resistance development in the target organisms there is a need to develop alternative antimicrobial approaches. Light-activated antimicrobial agents release singlet oxygen and free radicals which can kill adjacent bacteria and a wide range of cariogenic and periodontopathogenic bacteria has been shown to be susceptible to such agents. In the oral cavity these organisms are present as biofilms (dental plaques) which are less susceptible to traditional antimicrobial agents than bacterial suspensions. The results of these studies have shown that biofilm-grown oral bacteria are also susceptible to lethal photosensitization although the light energy doses required are grater than those needed to kill the organisms when they are grown as aqueous suspensions.

  9. Gastric spiral bacteria in small felids.

    Science.gov (United States)

    Kinsel, M J; Kovarik, P; Murnane, R D

    1998-06-01

    Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F. manul), one Canada lynx (F. lynx canadensis), two fishing cats (F. viverrina), two margays (F. wiedii), and two sand cats (F. margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P. uncia), one Siberian tiger (P. tigris altaica), and one jaguar (P. onca), necropsied during the same period had none. All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar. Histologically, the spiral bacteria were 5-14 microm long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells. Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrewlike to tumbling motility when viewed with phase contrast microscopy. The bacteria were 0.5-0.7 microm wide, with a periodicity of 0.65-1.1 microm in all cats. Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen. The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells. Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful. Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms. Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens.

  10. Exogenous fatty acid metabolism in bacteria.

    Science.gov (United States)

    Yao, Jiangwei; Rock, Charles O

    2017-10-01

    Bacterial type II fatty acid synthesis (FASII) is a target for novel antibiotic development. All bacteria encode for mechanisms to incorporate exogenous fatty acids, and some bacteria can use exogenous fatty acids to bypass FASII inhibition. Bacteria encode three different mechanisms for activating exogenous fatty acids for incorporation into phospholipid synthesis. Exogenous fatty acids are converted into acyl-CoA in Gammaproteobacteria such as E. coli. Acyl-CoA molecules constitute a separate pool from endogenously synthesized acyl-ACP. Acyl-CoA can be used for phospholipid synthesis or broken down by β-oxidation, but cannot be used for lipopolysaccharide synthesis. Exogenous fatty acids are converted into acyl-ACP in some Gram-negative bacteria. The resulting acyl-ACP undergoes the same fates as endogenously synthesized acyl-ACP. Exogenous fatty acids are converted into acyl-phosphates in Gram-positive bacteria, and can be used for phospholipid synthesis or become acyl-ACP. Only the order Lactobacillales can use exogenous fatty acids to bypass FASII inhibition. FASII shuts down completely in presence of exogenous fatty acids in Lactobacillales, allowing Lactobacillales to synthesize phospholipids entirely from exogenous fatty acids. Inhibition of FASII cannot be bypassed in other bacteria because FASII is only partially down-regulated in presence of exogenous fatty acid or FASII is required to synthesize essential metabolites such as β-hydroxyacyl-ACP. Certain selective pressures such as FASII inhibition or growth in biofilms can select for naturally occurring one step mutations that attenuate endogenous fatty acid synthesis. Although attempts have been made to estimate the natural prevalence of these mutants, culture-independent metagenomic methods would provide a better estimate. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  11. Differential staining of bacteria: gram stain.

    Science.gov (United States)

    Moyes, Rita B; Reynolds, Jackie; Breakwell, Donald P

    2009-11-01

    In 1884, Hans Christian Gram, a Danish doctor, developed a differential staining technique that is still the cornerstone of bacterial identification and taxonomic division. This multistep, sequential staining protocol separates bacteria into four groups based on cell morphology and cell wall structure: Gram-positive cocci, Gram-negative cocci, Gram-positive rods, and Gram-negative rods. The Gram stain is useful for assessing bacterial contamination of tissue culture samples or for examining the Gram stain status and morphological features of bacteria isolated from mixed or isolated bacterial cultures. (c) 2009 by John Wiley & Sons, Inc.

  12. Motile bacteria in a critical fluid mixture

    Science.gov (United States)

    Koumakis, Nick; Devailly, Clémence; Poon, Wilson C. K.

    2018-06-01

    We studied the swimming of Escherichia coli bacteria in the vicinity of the critical point in a solution of the nonionic surfactant C12E5 in buffer solution. In phase-contrast microscopy, each swimming cell produces a transient trail behind itself lasting several seconds. Comparing quantitative image analysis with simulations show that these trails are due to local phase reorganization triggered by differential adsorption. This contrasts with similar trails seen in bacteria swimming in liquid crystals, which are due to shear effects. We show how our trails are controlled, and use them to probe the structure and dynamics of critical fluctuations in the fluid medium.

  13. 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.

  14. 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?.

  15. Beer spoilage bacteria and hop resistance.

    Science.gov (United States)

    Sakamoto, Kanta; Konings, Wil N

    2003-12-31

    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 Megasphaera cerevisiae. They can spoil beer by turbidity, acidity and the production of unfavorable smell such as diacetyl or hydrogen sulfide. For the microbiological control, many advanced biotechnological techniques such as immunoassay and polymerase chain reaction (PCR) have been applied in place of the conventional and time-consuming method of incubation on culture media. Subsequently, a method is needed to determine whether the detected bacterium is capable of growing in beer or not. In lactic acid bacteria, hop resistance is crucial for their ability to grow in beer. Hop compounds, mainly iso-alpha-acids in beer, have antibacterial activity against Gram-positive bacteria. They act as ionophores which dissipate the pH gradient across the cytoplasmic membrane and reduce the proton motive force (pmf). Consequently, the pmf-dependent nutrient uptake is hampered, resulting in cell death. The hop-resistance mechanisms in lactic acid bacteria have been investigated. HorA was found to excrete hop compounds in an ATP-dependent manner from the cell membrane to outer medium. Additionally, increased proton pumping by the membrane bound H(+)-ATPase contributes to hop resistance. To energize such ATP-dependent transporters hop-resistant cells contain larger ATP pools than hop-sensitive cells. Furthermore, a pmf-dependent hop transporter was recently presented. Understanding the hop-resistance mechanisms has enabled the development of rapid methods to discriminate beer spoilage strains from nonspoilers. The horA-PCR method has been applied for bacterial control in breweries. Also, a discrimination method was developed based on ATP pool measurement in lactobacillus cells. However

  16. Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei)

    OpenAIRE

    Wilis Ari Setyati; Muhammad Zainuddin; Person Pesona Renta

    2017-01-01

    Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36...

  17. Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna.

    Science.gov (United States)

    Manakul, Patcharaporn; Peerakietkhajorn, Saranya; Matsuura, Tomoaki; Kato, Yasuhiko; Watanabe, Hajime

    2017-07-01

    The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Fermentation of D-Tagatose by Human Intestinal Bacteria and Dairy Lactic Acid Bacteria

    OpenAIRE

    Bertelsen, Hans; Andersen, Hans; Tvede, Michael

    2011-01-01

    A number of 174 normal or pathogenic human enteric bacteria and dairy lactic acid bacteria were screened for D-tagatose fermentation by incubation for 48 hours. Selection criteria for fermentation employed included a drop in pH below 5.5 and a distance to controls of more than 0.5. Only a few of the normal occurring enteric human bacteria were able to ferment D-tagatose, among those Enterococcus faecalis, Enterococcus faecium and Lactobacillus strains. D-Tagatose fermentation seems to be comm...

  19. Brilliant glyconanocapsules for trapping of bacteria.

    Science.gov (United States)

    Yan, Xibo; Sivignon, Adeline; Alcouffe, Pierre; Burdin, Béatrice; Favre-Bonté, Sabine; Bilyy, Rostyslav; Barnich, Nicolas; Fleury, Etienne; Ganachaud, François; Bernard, Julien

    2015-08-28

    Nanoprecipitation of miglyol into droplets surrounded by a functional glycopolymer generates nanocapsules of biointerest. Fluorophores are trapped in situ or post-grafted onto the crosslinked polymer shell for efficient imaging. The resulting colloids induce aggregation of bacteria through strong specific interactions and promote their facile removal.

  20. Brilliant glyconanocapsules for trapping of bacteria

    OpenAIRE

    Yan, Xibo; Sivignon, Adeline; Alcouffe, Pierre; Burdin, Béatrice; Favre-Bonté, Sabine; Bilyy, Rostyslav; Barnich, Nicolas; Fleury, Etienne; Ganachaud, François; Bernard, Julien

    2015-01-01

    Nanoprecipitation of miglyol into droplets surrounded by a functional glycopolymer generates nanocapsules of biointerest. Fluorophores are trapped in situ or post-grafted onto the crosslinked polymer shell for efficient imaging. The resulting colloids induce aggregation of bacteria through strong specific interactions and promote their facile removal.

  1. On Bunsen Burners, Bacteria and the Bible

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 2. On Bunsen Burners, Bacteria and the Bible. Milind Watve. Classroom Volume 1 Issue 2 February 1996 pp 84-89. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/02/0084-0089 ...

  2. The effects of bacteria on crystalline rock

    International Nuclear Information System (INIS)

    Brown, D.A.

    1994-01-01

    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 10 3 to 10 5 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

  3. Solvent-tolerant bacteria in biocatalysis.

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1998-01-01

    The toxicity of fine chemicals to the producer organism is a problem in several biotechnological production processes. In several instances, an organic phase can be used to extract the toxic product from the aqueous phase during a fermentation. With the discovery of solvent-tolerant bacteria, more

  4. OCCURRENCE OF PATHOGENIC BACTERIA ASSOCIATED WITH ...

    African Journals Online (AJOL)

    USER

    With the diminishing rate of natural fish resources globally, a reasonable percentage of fish and fish products .... from these artificial fish habitat, one may not be out of place to ... condition for bacteria reproduction and development in their host ...

  5. 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

  6. Antimicrobial resistant bacteria in the food chain

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar

    2003-01-01

    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...

  7. 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...

  8. (VAM) and phosphate solubilizing bacteria (PSB)

    African Journals Online (AJOL)

    User

    2013-09-18

    Sep 18, 2013 ... mycorrhiza (VAM), and phosphate solubilising bacteria (PSB) individually and in .... Two-way analysis of variance (ANOVA) was carried out at a 0.05 level of significance on the data and SPSS version 13.0 was used.

  9. 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...

  10. 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...

  11. Halophilic and haloalkaliphilic sulfur-oxidizing bacteria

    NARCIS (Netherlands)

    Sorokin, D.Y.; Banciu, H.; Robertson, L.A.; Kuenen, J.G.; Muntyan, M.S.; Muyzer, G.; Rosenberg, E.; DeLong, F.; Delong, E.; Lory, S.; Stackebrandt, E.; Thompson, F.

    2013-01-01

    Chemotrophic sulfur-oxidizing bacteria (SOB) represent an important functional group of microorganisms responsible for the dark oxidation of reduced sulfur compounds generated by sulfidogens. Until recently, only a single genus of halophilic SOB (Halothiobacillus) has been described, and nothing was

  12. Identification of marine methanol-utilizing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, M; Iwaki, H; Kouno, K; Inui, T

    1980-01-01

    A taxonomical study of 65 marine methanol-utilizing bacteria is described. They were Gram-negative, non-spore-forming rods with a polar flagellum and had marine bacterial properties and required vitamin B/sub 12/ for growth. All of them assimilated fructose in addition to C/sub 1/-compounds and produced acid oxidatively from fructose. Twenty-four strains assimilated only C/sub 1/-compounds. They were resistant to penicillin, oxytetracycline and 0/129 substance (Vibrio stat), and tolerant to 12% NaCl. Guanine-cytosine contents of deoxyribonucleic acid in typical strains fell in the range of 43.8 to 47.6%. Other morphological and physiological properties were almost the same as those of terrestrial methanol-utilizers. Bacteria in the first group (41 strains) were facultative methylotrophs and were divided into three subgroups by the assimilation of methylated amines, that is, subgroup I (30 strains) assimilated mono-, di- and tri-methylamine, subgroup II (9 strains) assimilated only mono-methylamine, the bacteria of subgroups I and II were named Alteromonas thalassomethanolica sp. nov. and subgroup III (2 strains) did not assimilate methylated amines, and was tentatively assigned as Alteromonas sp. The second group of bacteria (24 strains) was obligate methylotrophs, named Methylomonas thalassica sp. nov. and was divided into subgroup IV (15 strains) which assimilated mono-, di and tri-methylamine and subgroup V (9 strains) which assimilated mono-methylamine.

  13. Bacteria Isolated from Post-Partum Infections

    Directory of Open Access Journals (Sweden)

    Nahid Arianpour

    2009-06-01

    Full Text Available Objective: This study was undertaken with an aim to determine bacterial species involved in post partum infections and also their abundance in patients admitted to at Khanevadeh hospital. In this study out of three different kinds of postpartum infections (i.e. genital, breast and urinary tract, only genital infection is considered.Materials and Methods: Post partum infection among 6077 patients (inpatients and re-admitted patients of Khanevadeh hospital from 2003 till 2008 was studied in this descriptive study. Samples were collected from patients for laboratory diagnosis to find out the causative organisms.Results: Follow up of mothers after delivery revealed 7.59% (461 patients had post partum infection, out of which 1.03% (63 patients were re-hospitalized. Infection was more often among younger mothers. Bacteria isolated and identified were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora of the site of infection. Though, some pathogenic bacteria like Staphylococcus aureus, Neisseria gonorrhea, Chlamydia trachomatis,were also the causative agents. The commonest infection was infection at the site of episiotomy. Conclusion: Puerperal infection was detected in of 7.59% mothers. Bacteria isolated were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora. However; some pathogenic bacteria were isolated.

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

    DEFF Research Database (Denmark)

    Roberts, T.H.; Hejgaard, Jørn; Saunders, N.F.W

    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...

  15. 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...

  16. Multidrug transporters in lactic acid bacteria

    NARCIS (Netherlands)

    Mazurkiewicz, P; Sakamoto, K; Poelarends, GJ; Konings, WN

    Gram-positive lactic acid bacteria possess several Multi-Drug Resistance systems (MDRs) that excrete out of the cell a wide variety of mainly cationic lipophilic cytotoxic compounds as well as many clinically relevant antibiotics. These MDRs are either proton/drug antiporters belonging to the major

  17. Drug efflux proteins in multidrug resistant bacteria

    NARCIS (Netherlands)

    vanVeen, HW; Konings, WN

    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

  18. Bioluminescent hydrocarbonclastic bacteria of the Niger Delta ...

    African Journals Online (AJOL)

    Utilization of three petroleum hydrocarbons (Mobil SAE 40 Engine Oil, Diesel and Bonny light Crude Oil) by four bioluminescent bacteria (Vibrio harveyi, V. fisheri, Photobacterium leiognathi and P. Phosphoreum isolated from the Bonny estuary in the Niger Delta, Nigeria was investigated. Microbial utilization was monitored ...

  19. Pathomorphology and aerobic bacteria associated with pneumonia ...

    African Journals Online (AJOL)

    Pneumonia occurs in all ages of sheep and goats, in all breeds, in every country of the world causing heavy economic losses. The aim of this study was to determine the prevalence of pneumonia and aerobic bacteria flora associated with it in small ruminants slaughtered at the Nsukka abattoir. Pneumonic lung of small ...

  20. Metabolic plasticity for isoprenoid biosynthesis in bacteria.

    Science.gov (United States)

    Pérez-Gil, Jordi; Rodríguez-Concepción, Manuel

    2013-05-15

    Isoprenoids are a large family of compounds synthesized by all free-living organisms. In most bacteria, the common precursors of all isoprenoids are produced by the MEP (methylerythritol 4-phosphate) pathway. The MEP pathway is absent from archaea, fungi and animals (including humans), which synthesize their isoprenoid precursors using the completely unrelated MVA (mevalonate) pathway. Because the MEP pathway is essential in most bacterial pathogens (as well as in the malaria parasites), it has been proposed as a promising new target for the development of novel anti-infective agents. However, bacteria show a remarkable plasticity for isoprenoid biosynthesis that should be taken into account when targeting this metabolic pathway for the development of new antibiotics. For example, a few bacteria use the MVA pathway instead of the MEP pathway, whereas others possess the two full pathways, and some parasitic strains lack both the MVA and the MEP pathways (probably because they obtain their isoprenoids from host cells). Moreover, alternative enzymes and metabolic intermediates to those of the canonical MVA or MEP pathways exist in some organisms. Recent work has also shown that resistance to a block of the first steps of the MEP pathway can easily be developed because several enzymes unrelated to isoprenoid biosynthesis can produce pathway intermediates upon spontaneous mutations. In the present review, we discuss the major advances in our knowledge of the biochemical toolbox exploited by bacteria to synthesize the universal precursors for their essential isoprenoids.

  1. 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

  2. Tolerance of anaerobic bacteria to chlorinated solvents.

    Science.gov (United States)

    Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

    2014-01-01

    The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

  3. The proteolytic systems of lactic acid bacteria

    NARCIS (Netherlands)

    Kunji, Edmund R.S.; Mierau, Igor; Hagting, Anja; Poolman, Bert; Konings, Wil N.

    1996-01-01

    Proteolysis in dairy lactic acid bacteria has been studied in great detail by genetic, biochemical and ultrastructural methods. From these studies the picture emerges that the proteolytic systems of lactococci and lactobacilli are remarkably similar in their components and mode of action. The

  4. Proteolytic enzymes of lactic acid bacteria

    NARCIS (Netherlands)

    Law, J; Haandrikman, A

    The proteolytic system of lactic acid bacteria is essential for their growth in milk and contributes significantly to flavour development in fermented milk products where these microorganisms are used as starter cultures. The proteolytic system is composed of proteinases which initially cleave the

  5. Biological Potential of Chitinolytic Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara Skøtt; Andersen, Birgitte; Gram, Lone

    2016-01-01

    Chitinolytic microorganisms secrete a range of chitin modifying enzymes, which can be exploited for production of chitin derived products or as fungal or pest control agents. Here, we explored the potential of 11 marine bacteria (Pseudoalteromonadaceae, Vibrionaceae) for chitin degradation using...

  6. Exopolysaccharides produced by lactic acid bacteria

    NARCIS (Netherlands)

    Caggianiello, Graziano; Kleerebezem, Michiel; Spano, Giuseppe

    2016-01-01

    A wide range of lactic acid bacteria (LAB) is able to produce capsular or extracellular polysaccharides, with various chemical compositions and properties. Polysaccharides produced by LAB alter the rheological properties of the matrix in which they are dispersed, leading to typically viscous and

  7. Radiographic markers - A reservoir for bacteria?

    International Nuclear Information System (INIS)

    Tugwell, Jenna; Maddison, Adele

    2011-01-01

    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.

  8. Heterotrophic bacteria associated with the green alga

    NARCIS (Netherlands)

    Ismail, A.; Ktari, L.; Ahmed, M.; Bolhuis, H.; Bouhaouala-Zahar, B.; Stal, L.J.; Boudabbous, A.; El Bour, M.

    2018-01-01

    Heterotrophic bacteria associated with the green alga Ulva rigida, collected from the coast of Tunisia, were isolated andsubsequently identified by their 16S rRNA gene sequences and by phylogenetic analysis. The 71 isolates belong to four phyla:Proteobacteria (Alpha-and Gamma- subclasses),

  9. Evaluación de la cognición social y teoría de la mente en pacientes con enfermedad cerebelosa degenerativa aislada no dementes Social cognition and theory of mind assessment in non-demented patients with isolated cerebellar degeneration

    Directory of Open Access Journals (Sweden)

    Carlos G. Abel

    2007-06-01

    Full Text Available OBJETIVO: Investigar la hipótesis según la cual, el cerebelo podría participar en las alteraciones de la cognición social (CS. MÉTODO: Se administraron tests neuropsicológicos generales, de función ejecutiva (FE, de CS que evaluaban la capacidad de inferir el estado mental de otras personas y la escala de Depresión de Beck a 10 pacientes adultos con enfermedad cerebelosa adquirida aislada (GEC y a 10 controles (GCO apareados por edad, sexo y educación. Se analizaron los datos mediante ANOVA y correlación. RESULTADOS: El GEC obtuvo puntajes significativamente menores (p?0,05 que el grupo GCO en tareas de FE (Test de Wisconsin y preguntas de creencia (PCr de Teoría de la Mente (ToM. El rendimiento en las preguntas de control (PCo de ToM fue similar en ambos grupos. El menor rendimiento en las PCr correlacionó significativamente con una menor habilidad conceptual, la severidad de la apatía (NPI y de la ataxia estática. Las PCo correlacionaron con medidas de atención y de recuerdo diferido libre. CONCLUSÍON: El cerebelo contribuiría en el monitoreo de la conducta mediante el control de datos multimodales motores, cognitivos y emocionales.AIM: To investigate whether the cerebellum could participate in social cognition (SC. METHOD: General neuropsychological tests, executive tests (EF, social cognition tests, which assess the ability to infer other peoples’ mental states, and the Beck Depression Inventory were given to 10 non-demented patients with isolated cerebellar degenerative disease, and to 10 healthy controls matched for sex, age, and years of education. ANOVA and correlation coefficients were employed for the statistical analysis. RESULTS: Patients within the cerebellar group were significantly impaired (p?0.05 in EF test [Wisconsin Card Sorting Test (WSCT] and belief questions (BQ from Theory of Mind (ToM tests. Performance in control questions (CQ from ToM tests was similar for both groups. Lower scores in BQ correlated

  10. Distribución de grupos filogenéticos y factores de virulencia en cepas de Escherichia coli uropatógena productora de ß-lactamasa CTX-M-15 aisladas de pacientes de la comunidad en Mérida, Venezuela

    Directory of Open Access Journals (Sweden)

    Ysheth Millán

    Full Text Available En este estudio se determinó el perfil de distribución de grupos filogéneticos y la detección genética de factores de virulencia en cepas de Escherichia coli uropatógena (ECUP productoras de ß-lactamasa CTX-M-15. Veintiocho cepas fueron aisladas de pacientes con infección del tracto urinario (ITU que asistieron al Laboratorio de Salud Pública del estado Mérida, Venezuela, durante el lapso comprendido entre enero 2009 y julio 2011. La determinación de los grupos filogenéticos y la detección de seis genes de virulencia, fimH, fyuA, kpsMTII, usp, PAI y papAH, se realizó mediante amplificación por PCR. Quince cepas de 28 se ubicaron principalmente en el filogrupo A, seguidos por el B2 (12/28 y D (1/28. No se observó una relación directa entre la recurrencia o gravedad de la ITU y la distribución de los filogrupos. Todos los factores de virulencia estudiados se encontraron con la frecuencia más alta en el grupo B2. El perfil de virulencia prevalente estuvo conformado por la asociación de tres genes principales: fimH, fyuA y kpsMTII y en menor frecuencia, por la presencia de otros determinantes como usp, PAI y/o papAH. Estos resultados indican que la mayoría de ECUP estuvieron dotadas de tres propiedades virulentas importantes: adhesión, captación de hierro y evasión de la fagocitosis, las cuales favorecieron la producción de ITU recurrentes. Este es el primer trabajo que describe la asociación de grupos filogenéticos con el potencial de virulencia de cepas de ECUP productoras de ß-lactamasa CTX-M-15 en Venezuela.

  11. Evaluación de una esterasa de ácido ferúlico (Fae1A aislada del hongo del rumen Anaeromyces mucronatus sobre la degradación de la pared celular del heno de alfalfa y paja de trigo: Ensayo In vitro

    Directory of Open Access Journals (Sweden)

    José C. López O

    2015-01-01

    Full Text Available Las esterasas de ácido ferúlico son capaces de liberar compuestos fenólicos de la pared celular vegetal, aumentando el acceso a los polisacáridos. Se realizaron determinaciones In vitro con la finalidad de determinar el potencial de una esterasa de ácido ferúlico (Fae1A aislada del hongo del rumen Anaeromyces mucronatus. Esta estearasa se obtuvo de un trabajo previo realizado en el Centro de Investigación de Lethbridge, Alberta Canadá, a través de procesos de clonación y hetero-expresión del gen Fae1aA en una cepa de E. coli BL21. Tres niveles (0, 9 y 18 mg de proteína contenida en la enzima se combinaron con liquido ruminal e incubaron en 2 diferentes fuentes de fibra (heno de alfalfa y paja de trigo utilizando 15 repeticiones por tratamiento. La inclusión de la enzima incrementó (P <0.05 la desaparición de la materia seca en el heno de alfalfa, liberándose más cantidad (P <0.01 de azúcares reducidos (AR a las 4 y 12 h. Fae1A liberó más compuestos fenólicos del heno de alfalfa vs. la paja de trigo. Los compuestos fenólicos totales e individuales liberados de la alfalfa se incrementaron con el nivel de enzima añadida. En la paja de trigo, el ácido ferúlico se duplicó en comparación con el ácido p-cumárico. En conclusión, la adición de la Fae1A mejoró la cantidad de azucares reducidos y se liberaron compuestos fenólicos en el heno de alfalfa y la paja de trigo, lo que indica su potencial para ser usada como enzima fibrolítica y mejorar la digestibilidad de la fibra en los rumiantes.

  12. Fatty acids profile and nutritional composition of two tropical diatoms from the Costa Rican Pacific Coast; Perfil de ácidos grasos y composición nutricional de diatomeas tropicales aisladas de la costa del Pacífico de Costa Rica.

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Núñez, K.; Toledo-Aguero, P.

    2017-07-01

    Microalgae represent an important nutritional source for diverse organisms, therefore, their nutritional value, and more specifically, total lipid and fatty acid contents, must be considered. This study evaluated the nutritional contents and potential growth under controlled conditions of Nitzschia sp. and Chaetoceros sp. Tropical microalgae, isolated from the Gulf of Nicoya, Costa Rica. In both strains, the nutritional composition and the fatty acid profile were evaluated in exponential and stationary phases. With regards to fatty acids, Nitzschia sp. had more Eicosapentaenoic Acid (EPA) in both the exponential (32.80%) and stationary (27.20%) phases. The results in growth rate, production and biochemical composition indicated two tropical microalgae strains suitable for cultivation under controlled conditions. The studies of the phytoplankton in this geographical area is highly relevant because of its importance in the primary production of nutrients and the importance of finding sources of fatty acids such as the EPA. [Spanish] Las microalgas representan una fuente alimenticia importante para diversos organismos, por lo que su valor nutricional debe ser considerado, especialmente su contenido de lípidos totales y el perfil de ácidos grasos. Este estudio tuvo como objetivo evaluar el crecimiento y determinar la composición bioquímica de dos cepas de microalgas tropicales aisladas de la costa del Pacífico Central de Costa Rica, Nitzschia sp. y Chaetoceros sp. En ambas se evaluó la composición nutricional y perfil de ácidos grasos en fase exponencial y estacionaria. Nitzschia sp. tuvo mayor cantidad de ácido eicosapentanoico (EPA) en ambas fases (32.80% y 27.20%, respectivamente). Los resultados en tasa de crecimiento, producción y composición bioquímica, presentan dos cepas de microalgas tropicales aptas para su cultivo en condiciones controladas. Estudiar el fitoplancton de esta zona es muy relevante debido a su importancia en la producción primaria

  13. The interaction of bacteria and metal surfaces

    International Nuclear Information System (INIS)

    Mansfeld, Florian

    2007-01-01

    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 E corr 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

  14. The interaction of bacteria and metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mansfeld, Florian [Corrosion and Environmental Effects Laboratory (CEEL), The Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241 (United States)

    2007-10-10

    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 E{sub corr} 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. (author)

  15. [Methanotrophic bacteria of acid sphagnum bogs].

    Science.gov (United States)

    Dedysh, S N

    2002-01-01

    Acid sphagnum bogs cover a considerable part of the territory of Russia and are an important natural source of biogenic methane, which is formed in their anaerobic layers. A considerable portion of this methane is consumed in the aerobic part of the bog profile by acidophilic methanotrophic bacteria, which comprise the methane filter of sphagnum bogs and decrease CH4 emission to the atmosphere. For a long time, these bacteria escaped isolation, which became possible only after the elucidation of the optimal conditions of their functioning in situ: pH 4.5 to 5.5; temperature, from 15 to 20 degrees C; and low salt concentration in the solution. Reproduction of these conditions and rejection of earlier used media with a high content of biogenic elements allowed methanotrophic bacteria of two new genera and species--Methylocella palustris and Methylocapsa acidophila--to be isolated from the peat of sphagnum bogs of the northern part of European Russia and West Siberia. These bacteria are well adapted to the conditions in cold, acid, oligotrophic sphagnum bogs. They grow in a pH range of 4.2-7.5 with an optimum at 5.0-5.5, prefer moderate temperatures (15-25 degrees C) and media with a low content of mineral salts (200-500 mg/l), and are capable of active nitrogen fixation. Design of fluorescently labeled 16S rRNA-targeted oligonucleotide probes for the detection of Methylocella palustris and Methylocapsa acidophila and their application to the analysis of sphagnum peat samples showed that these bacteria represent dominant populations of methanotrophs with a density of 10(5)-10(6) cells/g peat. In addition to Methylocella and Methylocapsa populations, one more abundant population of methanotrophs was revealed (10(6) cells/g peat), which were phylogenetically close to the genus Methylocystis.

  16. Anaerobic bacteria in wastewater treatment plant.

    Science.gov (United States)

    Cyprowski, Marcin; Stobnicka-Kupiec, Agata; Ławniczek-Wałczyk, Anna; Bakal-Kijek, Aleksandra; Gołofit-Szymczak, Małgorzata; Górny, Rafał L

    2018-03-28

    The objective of this study was to assess exposure to anaerobic bacteria released into air from sewage and sludge at workplaces from a wastewater treatment plant (WWTP). Samples of both sewage and sludge were collected at six sampling points and bioaerosol samples were additionally collected (with the use of a 6-stage Andersen impactor) at ten workplaces covering different stages of the technological process. Qualitative identification of all isolated strains was performed using the biochemical API 20A test. Additionally, the determination of Clostridium pathogens was carried out using 16S rRNA gene sequence analysis. The average concentration of anaerobic bacteria in the sewage samples was 5.49 × 10 4 CFU/mL (GSD = 85.4) and in sludge-1.42 × 10 6 CFU/g (GSD = 5.1). In turn, the average airborne bacterial concentration was at the level of 50 CFU/m 3 (GSD = 5.83) and the highest bacterial contamination (4.06 × 10 3  CFU/m 3 ) was found in winter at the bar screens. In total, 16 bacterial species were determined, from which the predominant strains belonged to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera. The analysis revealed that mechanical treatment processes were responsible for a substantial emission of anaerobic bacteria into the air. In both the sewage and air samples, Clostridium perfringens pathogen was identified. Anaerobic bacteria were widely present both in the sewage and in the air at workplaces from the WWTP, especially when the technological process was performed in closed spaces. Anaerobic bacteria formed small aggregates with both wastewater droplets and dust particles of sewage sludge origin and as such may be responsible for adverse health outcomes in exposed workers.

  17. 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.

  18. 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.

  19. Time related total lactic acid bacteria population diversity and ...

    African Journals Online (AJOL)

    user

    2011-02-07

    Feb 7, 2011 ... the diversity and dynamics of lactic acid bacteria (LAB) population in fresh ..... combining morphological, biochemical and molecular data are important for ..... acid bacteria from fermented maize (Kenkey) and their interactions.

  20. Oh What a Tangled Biofilm Web Bacteria Weave

    Science.gov (United States)

    ... Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May 1, ... a suitable surface, some water and nutrients, and bacteria will likely put down stakes and form biofilms. ...

  1. The Effect of Bacteria Penetration on Chalk Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie

    number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment with B. licheniformis mainly spores were detected in the effluent. The core permeability decreased rapidly during injection of bacteria and a starvation period of 12 days did not allow......Bacteria selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery. Bacteria can plug the water-bearing zones of a reservoir, thus altering the flow paths and improving sweep efficiency. It is known that the bacteria can penetrate deeply...... into reservoirs, however, a complete understanding of the penetration behavior of bacteria is lacking, especially in chalk formations where the pore throat sizes are almost comparable with the sizes of bacteria vegetative cells. This study investigates the penetration of bacteria into chalk. Two bacteria types...

  2. Developing new bacteria subroutines in the SWAT model

    Science.gov (United States)

    Fecal bacteria observations from four different sites in Korea and the US demonstrate seasonal variability, showing a significant relationship with temperature (Figure 1); fecal indicator bacteria (FIB) concentrations are relatively higher in summer and lower in winter , including Stillwater river (...

  3. Bacteria Associated with Fresh Tilapia Fish (Oreochromis niloticus ...

    African Journals Online (AJOL)

    acer

    Keywords: Bacteria, Tilapia fish and Sokoto central market. INTRODUCTION ... The bacteria are transmitted by fish that have made contact ... with which a product spoils is also related to the .... Base on the percentage frequency of occurance ,.

  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. Have sex or not? Lessons from bacteria.

    Science.gov (United States)

    Lodé, T

    2012-01-01

    Sex is one of the greatest puzzles in evolutionary biology. A true meiotic process occurs only in eukaryotes, while in bacteria, gene transcription is fragmentary, so asexual reproduction in this case really means clonal reproduction. Sex could stem from a signal that leads to increased reproductive output of all interacting individuals and could be understood as a secondary consequence of primitive metabolic reactions. Meiotic sex evolved in proto-eukaryotes to solve a problem that bacteria did not have, namely a large amount of DNA material, occurring in an archaic step of proto-cell formation and genetic exchanges. Rather than providing selective advantages through reproduction, sex could be thought of as a series of separate events which combines step-by-step some very weak benefits of recombination, meiosis, gametogenesis and syngamy. Copyright © 2012 S. Karger AG, Basel.

  6. Mucosal immunity to pathogenic intestinal bacteria.

    Science.gov (United States)

    Perez-Lopez, Araceli; Behnsen, Judith; Nuccio, Sean-Paul; Raffatellu, Manuela

    2016-03-01

    The intestinal mucosa is a particularly dynamic environment in which the host constantly interacts with trillions of commensal microorganisms, known as the microbiota, and periodically interacts with pathogens of diverse nature. In this Review, we discuss how mucosal immunity is controlled in response to enteric bacterial pathogens, with a focus on the species that cause morbidity and mortality in humans. We explain how the microbiota can shape the immune response to pathogenic bacteria, and we detail innate and adaptive immune mechanisms that drive protective immunity against these pathogens. The vast diversity of the microbiota, pathogens and immune responses encountered in the intestines precludes discussion of all of the relevant players in this Review. Instead, we aim to provide a representative overview of how the intestinal immune system responds to pathogenic bacteria.

  7. Ancient bacteria show evidence of DNA repair

    DEFF Research Database (Denmark)

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

    2007-01-01

    -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...... 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...... that 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....

  8. Protein-Injection Machines in Bacteria.

    Science.gov (United States)

    Galán, Jorge E; Waksman, Gabriel

    2018-03-08

    Many bacteria have evolved specialized nanomachines with the remarkable ability to inject multiple bacterially encoded effector proteins into eukaryotic or prokaryotic cells. Known as type III, type IV, and type VI secretion systems, these machines play a central role in the pathogenic or symbiotic interactions between multiple bacteria and their eukaryotic hosts, or in the establishment of bacterial communities in a diversity of environments. Here we focus on recent progress elucidating the structure and assembly pathways of these machines. As many of the interactions shaped by these machines are of medical importance, they provide an opportunity to develop novel therapeutic approaches to combat important human diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Seeing Streptococcus pneumoniae, a Common Killer Bacteria

    DEFF Research Database (Denmark)

    Kjærgaard, Rikke Schmidt; Andersen, Ebbe Sloth

    2014-01-01

    Look around you. The diversity and complexity of life on earth is overwhelming and data continues to grow. In our desire to understand and explain everything scientifically from molecular evolution to supernovas we depend on visual representations. This paper investigates visual representations...... of the bacteria Streptococcus pneumoniae by use of ink, watercolours and computer graphics. We propose a novel artistic visual rendering of Streptococcus pneumoniae and ask what the value of these kind of representations are compared to traditional scientific data. We ask if drawings and computer......-assisted representations can add to our scientific knowledge about this dangerous bacteria. Is there still a role for the scientific illustrator in the scientific process and synthesis of scientific knowledge?...

  10. [Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria].

    Science.gov (United States)

    Boiandin, A N; Kalacheva, G S; Rodicheva, E K; Volova, T G

    2008-01-01

    The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDSM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa (Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40-70% of the cell dry mass weight) were determined. The capacity of synthesizing two- and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates.

  11. 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...

  12. Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

    OpenAIRE

    Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

    2014-01-01

    This article belongs to the Special Issue Selected Papers from the 14th International Symposium on Marine Natural Products Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S...

  13. Bactericidal effects of antibiotics on slowly growing and nongrowing bacteria.

    OpenAIRE

    Eng, R H; Padberg, F T; Smith, S M; Tan, E N; Cherubin, C E

    1991-01-01

    Antimicrobial agents are most often tested against bacteria in the log phase of multiplication to produce the maximum bactericidal effect. In an infection, bacteria may multiply less optimally. We examined the effects of several classes of antimicrobial agents to determine their actions on gram-positive and gram-negative bacteria during nongrowing and slowly growing phases. Only ciprofloxacin and ofloxacin exhibited bactericidal activity against nongrowing gram-negative bacteria, and no antib...

  14. [Application of anaerobic bacteria detection in oral and maxillofacial infection].

    Science.gov (United States)

    Bao, Zhen-ying; Lin, Qin; Meng, Yan-hong; He, Chun; Su, Jia-zeng; Peng, Xin

    2016-02-18

    To investigate the distribution and drug resistance of anaerobic bacteria in the patients with oral and maxillofacial infection. Aerobic and anaerobic bacteria cultures from 61 specimens of pus from the patients with oral and maxillofacial infection in the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology were identified. The culture type was evaluated by API 20A kit and drug resistance test was performed by Etest method. The clinical data and antibacterial agents for the treatment of the 61 cases were collected, and the final outcomes were recorded. The bacteria cultures were isolated from all the specimens, with aerobic bacteria only in 6 cases (9.8%), anaerobic bacteria only in 7 cases (11.5%), and both aerobic and anaerobic bacteria in 48 cases (78.7%). There were 55 infected cases (90.2%) with anaerobic bacteria, and 81 anaerobic bacteria stains were isolated. The highest bacteria isolation rate of Gram positive anaerobic bacteria could be found in Peptostreptococcus, Bifidobacterium and Pemphigus propionibacterium. No cefoxitin, amoxicillin/carat acid resistant strain was detected in the above three Gram positive anaerobic bacteria. The highest bacteria isolation rate of Gram negative anaerobic bacteria could be detected in Porphyromonas and Prevotella. No metronidazole, cefoxitin, amoxicillin/carat acid resistant strain was found in the two Gram negative anaerobic bacteria. In the study, 48 patients with oral and maxillofacial infection were treated according to the results of drug resistance testing, and the clinical cure rate was 81.3%. Mixed aerobic and anaerobic bacteria cultures are very common in most oral and maxillofacial infection patients. Anaerobic bacteria culture and drug resistance testing play an important role in clinical treatment.

  15. Cellulase Production by Bacteria: A Review

    OpenAIRE

    Sadhu Sangrila; Maiti Tushar Kanti

    2013-01-01

    Cellulose is an abundant natural biopolymer on earth and most dominating Agricultural waste. This cellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. It can be degraded by cellulase produced by cellulolytic bacteria. This enzyme has various industrial applications and now considered as major group of industrial enzyme. The review discusses application of cellulase, classification of cellulase, quantification...

  16. 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.

  17. Chemotactic waves of bacteria at the mesoscale

    OpenAIRE

    Calvez, Vincent

    2016-01-01

    The existence of travelling waves for a model of concentration waves of bacteria is investigated. The model consists in a kinetic equation for the biased motion of cells following a run-and-tumble process, coupled with two reaction-diffusion equations for the chemical signals. Strong mathematical difficulties arise in comparison with the diffusive regime which was studied in a previous work. The cornerstone of the proof consists in establishing monotonicity properties of the spatial density o...

  18. Transfer of DNA from Bacteria to Eukaryotes

    Directory of Open Access Journals (Sweden)

    Benoît Lacroix

    2016-07-01

    Full Text Available Historically, the members of the Agrobacterium genus have been considered the only bacterial species naturally able to transfer and integrate DNA into the genomes of their eukaryotic hosts. Yet, increasing evidence suggests that this ability to genetically transform eukaryotic host cells might be more widespread in the bacterial world. Indeed, analyses of accumulating genomic data reveal cases of horizontal gene transfer from bacteria to eukaryotes and suggest that it represents a significant force in adaptive evolution of eukaryotic species. Specifically, recent reports indicate that bacteria other than Agrobacterium, such as Bartonella henselae (a zoonotic pathogen, Rhizobium etli (a plant-symbiotic bacterium related to Agrobacterium, or even Escherichia coli, have the ability to genetically transform their host cells under laboratory conditions. This DNA transfer relies on type IV secretion systems (T4SSs, the molecular machines that transport macromolecules during conjugative plasmid transfer and also during transport of proteins and/or DNA to the eukaryotic recipient cells. In this review article, we explore the extent of possible transfer of genetic information from bacteria to eukaryotic cells as well as the evolutionary implications and potential applications of this transfer.

  19. Intracellular bacteria: the origin of dinoflagellate toxicity.

    Science.gov (United States)

    Silva, E S

    1990-01-01

    Dinoflagellate blooms of the same species have been registered either as toxic or nontoxic and, in the latter case, toxicity may be of different types. A hypothesis has been formulated according to which the bacteria having in some way taken part in the toxin formation are either inside the dinoflagellate cell or in the nutritive liquid. The presence of intracellular bacteria in those microorganisms has been studied mainly in material from cultures, a few from the sea, and several strains were isolated from different species. Experiments with crossed inoculations have shown that the bacterial strain from Gonyaulax tamarensis caused the cells of some other species to become toxic. From nontoxic clonal cultures of Prorocentrum balticum, Glenodinium foliaceum, and Gyrodinium instriatum, after inoculation of that bacterial strain, cultures were obtained whose cell extracts showed the same kind of toxicity as G. tamarensis. No toxic action could be found in the extracts of the bacterial cells form the assayed strains. The interference of intracellular bacteria in the metabolism of dinoflagellates must be the main cause of their toxicity.

  20. Acoustic manipulation of bacteria cells suspensions

    Science.gov (United States)

    GutiéRrez-Ramos, Salomé; Hoyos, Mauricio; Aider, Jean Luc; Ruiz, Carlos; Acoustofluidics Team Team; Soft; Bio Group Collaboration

    An acoustic contacless manipulation gives advantages in the exploration of the complex dynamics enviroment that active matter exhibits. Our works reports the control confinement and dispersion of Escherichia coliRP437-pZA3R-YFP suspensions (M9Glu-Ca) via acoustic levitation.The manipulation of the bacteria bath in a parallel plate resonator is achieved using the acoustic radiation force and the secondary radiation force. The primary radiation force generates levitation of the bacteria cells at the nodal plane of the ultrasonic standing wave generated inside the resonator. On the other side, secondary forces leads to the consolidation of stable aggregates. All the experiments were performed in the acoustic trap described, where we excite the emission plate with a continuous sinusoidal signal at a frequency in the order of MHz and a quartz slide as the reflector plate. In a typical experiment we observed that, before the input of the signal, the bacteria cells exhibit their typical run and tumble behavior and after the sound is turned on all of them displace towards the nodal plane, and instantaneously the aggregation begins in this region. CNRS French National Space Studies, CONACYT Mexico.

  1. Fecal indicator bacteria at Havana Bay

    International Nuclear Information System (INIS)

    Lopez Perez, Lisse; Gomez D'Angelo, Yamiris; Beltran Gonzalez, Jesus; Alvarez Valiente, Reinaldo

    2013-01-01

    Aims: Fecal indicator bacteria concentrations were evaluated in Havana Bay. Methods: Concentrations of traditional fecal indicator bacteria were calculated between April 2010 and February 2011, by MPN methods. Concentrations of thermo tolerant coliform (CTT), Escherichia coli, fecal streptococci (EF), intestinal enterococci (ENT) in seawater, and Clostridium perfringens in sediment surface, were determined. Results: CTT and E. coli levels were far above Cuban water quality standard for indirect contact with water, showing the negative influence of sewage and rivers on the bay. The EF and ENT were measured during sewage spills at the discharge site and they were suitable indicators of fecal contamination, but these indicators didn't show the same behavior in other selected sites. This result comes from its well-known inactivation by solar light in tropical zones and the presumable presence of humid acids in the waters of the bay. Conclusion: Fecal indicator bacteria and its statistical relationships reflect recent and chronic fecal contamination at the bay and near shores.

  2. Alkaline phosphatase activity of rumen bacteria.

    Science.gov (United States)

    Cheng, K J; Costerton, J W

    1977-11-01

    Of the 54 strains of rumen bacteria examined for alkaline phosphatase (APase) production, 9 of 33 gram-negative strains and none of 21 gram-positive strains produced the enzyme. The APase of the cells of the three strains of Bacteroides ruminicola that produced significant amounts of the enzyme was located in the periplasmic area of the cell envelope, whereas the enzyme was located in the strains of Selenomonas ruminantium and Succinivibrio dextrinosolvens was associated with the outer membrane. The localization of APase production in the cells of natural populations of rumen bacteria from hay-fed sheep was accomplished by reaction product deposition, and both the proportion of APase-producing bacteria and the location of the enzyme in the cell envelope of the producing cells could be determined. We suggest that this procedure is useful in detecting shifts in the bacterial population and the release of cell-bound APase that accompany feedlot bloat and other sequelae of dietary manipulation in ruminants.

  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. Magnesium and manganese content of halophilic bacteria

    International Nuclear Information System (INIS)

    de Medicis, E.; Paquette, J.; Gauthier, J.J.; Shapcott, D.

    1986-01-01

    Magnesium and manganese contents were measured by atomic absorption spectrophotometry in bacteria of several halophilic levels, in Vibrio costicola, a moderately halophilic eubacterium growing in 1 M NaCl, Halobacterium volcanii, a halophilic archaebacterium growing in 2.5 NaCl, Halobacterium cutirubrum, an extremely halophilic archaebacterium growing in 4 M NaCl, and Escherichia coli, a nonhalophilic eubacterium growing in 0.17 M NaCl. Magnesium and manganese contents varied with the growth phase, being maximal at the early log phase. Magnesium and manganese molalities in cell water were shown to increase with the halophilic character of the logarithmically growing bacteria, from 30 mmol of Mg per kg of cell water and 0.37 mmol of Mn per kg of cell water for E. coli to 102 mmol of Mg per kg of cell water and 1.6 mmol of Mn per kg of cell water for H cutirubrum. The intracellular concentrations of manganese were determined independently by a radioactive tracer technique in V. costicola and H. volcanii. The values obtained by 54 Mn loading represented about 70% of the values obtained by atomic absorption. The increase of magnesium and manganese contents associated with the halophilic character of the bacteria suggests that manganese and magnesium play a role in haloadaptation

  5. Fish skin bacteria: Colonial and cellular hydrophobicity.

    Science.gov (United States)

    Sar, N; Rosenberg, E

    1987-05-01

    Bacteria were desorbed from the skin of healthy, fast-swimming fish by several procedures, including brief exposure to sonic oscillation and treatment with nontoxic surface active agents. The surface properties of these bacteria were studied by measuring their adhesion to hexadecane, as well as by a newly developed, simple method for studying the hydrophobicity of bacterial lawns. This method, referred to as the "Direction of Spreading" (DOS) method, consists of recording the direction to which a water drop spreads when introduced at the border between bacterial lawns and other surfaces. Of the 13 fish skin isolates examined, two strains were as hydrophobic as polystyrene by the DOS method. Suspended cells of one of these strains adhered strongly to hexadecane (84%), whereas cells of the other strain adhered poorly (13%). Another strain which was almost as hydrophobic as polystyrene by the DOS method did not adhere to hexadecane at all. Similarly, lawns of three other strains were more hydrophobic than glass by the DOS method, but cell suspensions prepared from these colonies showed little or no adhesion to hexadecane. The high colonial but relatively low cellular hydrophobicity could be due to a hydrophobic slime that is removed during the suspension and washing procedures. The possibility that specific bacteria assist in fish locomotion by changing the surface properties of the fish skin and by producing drag-reducing polymers is discussed.

  6. Engineering bacteria for enhanced polyhydroxyalkanoates (PHA biosynthesis

    Directory of Open Access Journals (Sweden)

    Guo-Qiang Chen

    2017-09-01

    Full Text Available Polyhydroxyalkanoates (PHA have been produced by some bacteria as bioplastics for many years. Yet their commercialization is still on the way. A few issues are related to the difficulty of PHA commercialization: namely, high cost and instabilities on molecular weights (Mw and structures, thus instability on thermo-mechanical properties. The high cost is the result of complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and slow growth of microorganisms as well as difficulty of downstream separation. Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles, developments of engineering approaches for the extremophiles, increase on carbon substrates to PHA conversion and controlling Mw of PHA. The concept proof studies could still be conducted on E. coli or Pseudomonas spp. that are easily used for molecular manipulations. In this review, we will use E. coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.

  7. Contaminant bacteria in traditional-packed honey

    Directory of Open Access Journals (Sweden)

    Hening Tjaturina Pramesti

    2007-03-01

    Full Text Available Honey may be contaminated by microorganisms during its harvesting, processing, and packaging. Honey selected for clinical purposes must safe, sterile, and contain antimicrobial activity, so it must be evaluated using laboratory testing. The aim of this descriptive laboratory study was to isolate and identify the bacterial contaminant in the traditional-packed honey dealing with the use of honey for medical purposes. the colony forming units of honey sample cultured on blood agar were counted using Stuart bacterial colony counter. The suspected bacterial colonies were isolated and identified based on cultural morphology characteristics. The isolates of suspected bacterial colonies were stained according to Gram and Klein method and then were examined by the biochemical reaction. The results showed that there were two contaminant bacteria. Gram-positive cocci which were presumptively identified as coagulase-negative Staphylococci and gram-positive rods which were presumptively identified as Bacillus subtilis. In conclusion, the contaminant bacteria were regarded as low pathogen bacteria. The subtilin enzyme of B subtilis may cause an allergic reaction and coagulase-negative Staphylococci, Staphylococcus epidermidis is also an opportunist pathogen. Inevitably, for medical purposes, traditional-packed honey must be well filtered, water content above 18%, and standardized sterilization without loss of an antibacterial activity or change in properties.

  8. Excitons in intact cells of photosynthetic bacteria.

    Science.gov (United States)

    Freiberg, Arvi; Pajusalu, Mihkel; Rätsep, Margus

    2013-09-26

    Live cells and regular crystals seem fundamentally incompatible. Still, effects characteristic to ideal crystals, such as coherent sharing of excitation, have been recently used in many studies to explain the behavior of several photosynthetic complexes, especially the inner workings of the light-harvesting apparatus of the oldest known photosynthetic organisms, the purple bacteria. To this date, there has been no concrete evidence that the same effects are instrumental in real living cells, leaving a possibility that this is an artifact of unnatural study conditions, not a real effect relevant to the biological operation of bacteria. Hereby, we demonstrate survival of collective coherent excitations (excitons) in intact cells of photosynthetic purple bacteria. This is done by using excitation anisotropy spectroscopy for tracking the temperature-dependent evolution of exciton bands in light-harvesting systems of increasing structural complexity. The temperature was gradually raised from 4.5 K to ambient temperature, and the complexity of the systems ranged from detergent-isolated complexes to complete bacterial cells. The results provide conclusive evidence that excitons are indeed one of the key elements contributing to the energetic and dynamic properties of photosynthetic organisms.

  9. NREL Scientists Model Methane-Eating Bacteria | News | NREL

    Science.gov (United States)

    Scientists Model Methane-Eating Bacteria News Release: NREL Scientists Model Methane-Eating Bacteria February 13, 2018 Nature is full of surprises - not to mention solutions. A research team ) recently explored the possibilities provided by the natural world by researching how the bacteria

  10. 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

  11. Isolation and characterization of feather degrading bacteria from ...

    African Journals Online (AJOL)

    This study is aimed at isolating and characterizing new culturable feather degrading bacteria from soils of the University of Mauritius Farm. Bacteria that were isolated were tested for their capability to grow on feather meal agar (FMA). Proteolytic bacteria were tested for feather degradation and were further identified ...

  12. Bacteria associated with cultures of psathyrella atroumbonata (Pleger)

    African Journals Online (AJOL)

    These bacteria include Bacillus licheniformis, Bacillus subtilis, Leuconostoc mesenteroides, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus. The average bacteria count was 1.0 x 106 cfu/ml and these bacteria grew within pH range of 5.0 and 9.0. the optimum temperature range of growth lied ...

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

    NARCIS (Netherlands)

    Kooij, 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

  14. Bacteria associated with contamination of ready-to-eat (RTE ...

    African Journals Online (AJOL)

    The bacteria associated with contamination of ready-to-eat (RTE) cooked rice in Lagos, Nigeria were studied using standard microbiological methods. The objective of this study was to investigate the distribution of pathogenic bacteria recovered from RTE cooked rice in Lagos, assess bacteria load in the contaminated RTE ...

  15. 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

  16. Isolation and Presumptive Identification of Adherent Epithelial Bacteria (“Epimural” Bacteria) from the Ovine Rumen Wall

    OpenAIRE

    Mead, Lorna J.; Jones, G. A.

    1981-01-01

    One hundred sixty-one strains of adherent bacteria were isolated under anaerobic conditions from four sites on the rumen epithelial surface of sheep fed hay or a hay-grain ration. Before isolation of bacteria, rumen tissue was washed six times in an anaerobic dilution solution, and viable bacteria suspended in the washings were counted. Calculation indicated that unattached bacteria would have been removed from the tissue by this procedure, but a slow and progressive release of attached bacte...

  17. Ascitis fetal masiva idiopática aislada

    Directory of Open Access Journals (Sweden)

    Yolimar Navarro Briceño

    2016-08-01

    Full Text Available La ascitis fetal esta comúnmente asociada a malformaciones gastrointestinales y urinarias, anemia, infección y anomalías cromosómicas. La ascitis fetal masiva idiopática es rara. Se reporta un caso de una embarazada de 33 años referida a las 17 semanas después que se detectó ascitis en ausencia de anomalías estructurales. La evaluación cardiaca y las pruebas diagnósticas de infecciones virales fueron negativas. A las 28 semanas se detectó ascitis masiva sin otros signos de hidrops fetal. La velocidad sistólica pico de la arteria cerebral media fetal estaba elevada. El Doppler de la arteria umbilical, crecimiento fetal y volumen de líquido amniótico estaban normales. El ecocardiograma fetal estaba normal. Se realizó la amniocentesis con resultados normales del cariotipo. A pesar de la persistencia de la ascitis masiva durante el seguimiento, el crecimiento fetal y el volumen de líquido amniótico eran normales con valores elevados de la velocidad sistólica pico de la arteria cerebral media fetal. A las 33 semanas la paciente se realizó cesárea de emergencia por sufrimiento fetal agudo. Se obtuvo un recién nacido vivo femenino normal con valores normales de hemoglobina al nacer. El flujo vascular hepático, vesical y hepato-portal fueron normales. La ascitis se resolvió completamente al octavo día después del nacimiento y el recién nacido fue dado de alta a los 15 días.

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

    International Nuclear Information System (INIS)

    Malkin, A.J.

    2010-01-01

    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

  19. Screening and characterization of phosphate solubilizing bacteria from isolate of thermophilic bacteria

    Science.gov (United States)

    Yulianti, Evy; Rakhmawati, Anna

    2017-08-01

    The aims of this study were to select bacteria that has the ability to dissolve phosphate from thermophilic bacteria isolates after the Merapi eruption. Five isolates of selected bacteria was characterized and continued with identification. Selection was done by using a pikovskaya selective medium. Bacterial isolates were grown in selective medium and incubated for 48 hours at temperature of 55 ° C. Characterization was done by looking at the cell and colony morphology, physiological and biochemical properties. Identification was done with the Profile Matching method based on the reference genus Oscillospira traced through Bergey's Manual of Determinative Bacteriology. Dendogram was created based on similarity index SSM. The results showed there were 14 isolates of bacteria that were able to dissolve phosphate indicated by a clear zone surrounding the bacterial colony on selective media. Five isolates were selected with the largest clear zone. Isolates D79, D92, D110a, D135 and D75 have different characters. The result of phenotypic characters identification with Genus Oscillospira profile has a percentage of 100% similarity to isolate D92 and D110a; 92.31% for isolates D79, and 84.6% for isolates D75 and D135. Dendogram generated from average linkage algorithm / UPGMA using the Simple Matching Coefficient (SSM) algorithms showed, isolate thermophilic bacteria D75 and D135 are combined together to form cluster 1. D110a and D92 form a sub cluster A. Sub cluster A and D79 form cluster 2

  20. Screening and biological characteristics of fufenozide degrading bacteria

    Science.gov (United States)

    Xu, Chenhao; Gong, Mingfu; Guan, Qinlan; Deng, Xia; Deng, Hongyan; Huang, Jiao

    2018-04-01

    Fufenozide was a novel pesticide for the control of Lepidoptera pests, which was highly toxic to silkworm. Fufenozide-contaminated soil samples were collected and the bacteria that degrade fufenozide were isolated and screened by selective medium. The colony characteristics, cell characteristics and degradation characteristics in different concentrations fufenozide of the fufenozide degrading bacteria were studied. The results indicated that seven strains of fufenozide degradeing bacteria, named as DDH01, DDH03, DDH04, DDH04, DDH05, DDH07 and DDH07 respectively, were isolated from soil contaminated with fufenozide. DDH01, DDH02, DDH04 and DDH05 of seven fufenozide degrading bacteria, was gram-positive bacteria, and DDH03, DDH06 and DDH07 was gram-negative bacteria. All of seven strains of fufenozide degrading bacteria were not spores, weeks flagella, rod-shaped bacteria. DDH06 and DDH07 had capsules, and the remaining five strains had not capsule. The colonies formed by seven strains of fufenozide degradation bacteria on beef extract peptone medium plate were milky white colonies with irregular edges, thinner lawn, smaller colony with smooth surface. The growth of 7 strains of fufenozide degradation bacteria was significantly affected by the concentration of fufenozide, All of 7 strains grown in the range from 0.00025 g/mL to 1 g/mL of 10% fufenozide suspension. DDH2 was the best among the 7 strains of fufenozide degrading bacteria grown in 10% fufenozide suspension medium.

  1. Probiotic bacteria: selective enumeration and survival in dairy foods.

    Science.gov (United States)

    Shah, N P

    2000-04-01

    A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and Lactobacillus casei. Because of the potential health benefits, these organisms are increasingly incorporated into dairy foods. However, studies have shown low viability of probiotics in market preparations. In order to assess viability of probiotic bacteria, it is important to have a working method for selective enumeration of these probiotic bacteria. Viability of probiotic bacteria is important in order to provide health benefits. Viability of probiotic bacteria can be improved by appropriate selection of acid and bile resistant strains, use of oxygen impermeable containers, two-step fermentation, micro-encapsulation, stress adaptation, incorporation of micronutrients such as peptides and amino acids and by sonication of yogurt bacteria. This review will cover selective enumeration and survival of probiotic bacteria in dairy foods.

  2. La inoculación de plantas con Pantoea sp., bacteria solubilizadora de fosfatos, incrementa la concentración de P en los tejidos foliares Plant inoculation with Pantoea sp., phosphate solubilising-bacteria increases P concentration in leaf tissues

    Directory of Open Access Journals (Sweden)

    Ortega-Rodés Patricia

    2008-07-01

    Full Text Available El fósforo (P es un macronutriente mineral esencial para las plantas. Aunque puede encontrarse en los suelos en diferentes formas minerales, la baja solubilidad de estos disminuye su disponibilidad para las plantas, y el nutriente debe aplicarse como fertilizante a los cultivos. Las reservas mundiales de P son limitadas y tendrán una reducción considerable en los próximos años. Usar microorganismos solubilizadores de fosfatos como inoculante para los cultivos es una alternativa biotecnológica para incrementar la disponibilidad del nutriente. Pantoea sp. (cepa 9C es una bacteria endofítica fijadora de nitrógeno, aislada del interior de tallos de la caña de azúcar (Loiret et ál., 2004; este microorganismo produjo halos de solubilización con tamaños de hasta 6 mm en medio sólido NBRI-P en 7 días a 30 ºC, y en ese tiempo y condiciones solubilizó Ca3(PO42 en el medio líquido hasta acumular 1128 μg P mL-1. La bacteria sobrevivió durante 35 días en un sustrato preparado con mezcla de Vermiculita y suelo ferralítico rojo (Cambisol Ferrálico, ródico, alcanzando poblaciones de 3,2 x 1015 células g-1. Plantas de rábano (Raphanus sativus, L. var. Scarlet Globe, de alta demanda de P y crecimiento rápido, usadas como modelo y cultivadas en suelos inoculados con el microorganismo, absorbieron más P que las plantas no inoculadas, alcanzando en los tejidos foliares concentraciones ≥ 3500 ppm P base seca. Palabras clave: bacteria endofítica; solubilización de fosfatos; rábano (Raphanus sativus, L.; caña de azúcar (Saccharum híbrido.Phosphorus is an essential mineral macronutrient for plant growth and development. Although it can be found in soils in different mineral forms, its low solubility decrease its availability for plants; the nutrient should be added to crops as fertiliser. World sources of P are limited and in the near future they will suffer a remarkable decrease. Using P solubiliser microorganisms as

  3. Superfícies do ambiente hospitalar como possíveis reservatórios de bactérias resistentes: uma revisão Superficies inanimadas del ambiente hospitalario como posibles reservorios de bacterias resistentes: una revisión Surfaces of the hospital environment as possible deposits of resistant bacteria: a review

    Directory of Open Access Journals (Sweden)

    Adriana Cristina de Oliveira

    2010-12-01

    microorganismos. Se verificó semejanza en las cepas aisladas de pacientes colonizados y/o infectados y del ambiente por tipificación molecular. Esas evidencias refuerzan la necesidad de conocimiento y control de fuentes de patógenos en el ambiente hospitalario.The main objective of this study is to identify, in the literature, articles about the occurrence of contamination from inanimate surfaces and a possible dissemination of resistant bacteria in the hospital environment. A bibliographic survey was performed with articles published in the databases LILACS, MEDLINE, Science Direct, SCOPUS and ISI Web of Knowledge, between 2000 and 2008. Twenty-one articles were selected and analyzed. The analyzed studies highlighted the presence of bacteria on monitors, bed grids, tables, faucets, telephones, keyboards and other objects. There was a prevalence of Staphylococcus aureus resistant to methicillin, Clostridium difficile, Acinetobacter baumannii and Enterococcus resistant to vancomycin, being the predictive factor the previous occupation of patients colonized by these microorganisms. There was a similarity observed among the isolated strains of colonized and/or infected patients and the strains of the environment by molecular typification. These evidences reinforce the need for knowledge and control of the sources of pathogens in the hospital environment.

  4. INTEGRACIÓN DE INDUCCIÓN DE RESISTENCIA CON BACTERIAS QUITINOLÍTICAS EN EL CONTROL DE LA SIGATOKA NEGRA (Mycosphaerella fijiensis Morelet EN BANANO INTEGRATION OF INDUCED RESISTANCE WITH CHITINOLYTIC BACTERIA IN BLACK SIGATOKA CONTROL (Mycosphaerella fijiensis Morelet IN BANANA

    Directory of Open Access Journals (Sweden)

    Catalina María Zuluaga Amaya

    2007-12-01

    Full Text Available Se evaluó en condiciones de campo en la zona bananera de Urabá-Colombia, el efecto de inductores de resistencia y bacterias quitinolíticas sobre el desarrollo de la Sigatoka Negra en plantas de banano del cultivar Gran Enano. Como inductores de resistencia se utilizaron acibenzolar-s-metil (ASM (20 cm³ · ha-1 i.a. y ácido salicílico (AS (20 cm³ · ha-1 i.a cada uno en rotación y en mezcla con fungicidas utilizados en el control convencional de la enfermedad; se evaluó también la mezcla de estos inductores con bacterias quitinolíticas aisladas de la filosfera de banano; así como el efecto del fungicida biológico Biofun® ( 1,5 L · ha-1 de p.c. en rotación con fungicidas y en mezcla con ASM. La aplicación de ASM en rotación y en mezcla con fungicidas convencionales presentó un control de la enfermedad hasta un 50% mayor al obtenido con el control convencional, evidenciado esto en los valores más bajos del área bajo la curva del índice de severidad de la enfermedad (IS y más altos de hojas sanas (HS al momento de la floración. Los tratamientos, que incluyeron AS en rotación y mezcla con fungicidas convencionales, al igual que el producto Biofun® en rotación y en mezcla con ASM, mostraron un control de la enfermedad estadísticamente igual al obtenido con el control convencional, lo cual reveló una reducción de 46 - 100% de la cantidad de fungicidas convencionales usados en el control de la Sigatoka Negra.The effect of resistance elicitors and chitinolytic bacteria was evaluated on Black Sigatoka control in banana plants, in field conditions in Urabá-Colombia. Acibenzolar-s-metil (ASM (20 cm³ · ha- 1 a.i. and salicilyc acid (SA (20 cm³ a.i.ha-1 were used in rotation and mixture with conventional fungicides, and in mixture with chitinolytic bacteria isolated from banana phyllosphere. Biological fungicide Biofun® ( 1,5 L · ha-1 de p.c. was also tested in rotation and mixture with ASM. When fungicides were in rotation

  5. Introduce of Viable But Nonculturable Bacteria

    Directory of Open Access Journals (Sweden)

    Mehdi Hassanshahian

    2008-03-01

    Full Text Available Viable-But-Nonculturable-State (VBNC is the condition in which bacteria fail to grow on their routine bacteriological media where they would normally grow and develop into colonies, but are still alive and capable of renewed metabolic activity. VBNC state is useful for evaluating public health and for ascertaining the sterility of drinking water, pharmaceuticals, and foodstuff. A number of bacteria, mostly pathogenic to humans, have been proved to enter into this state in response to natural stresses such as starvation, incubation out of optimum growth temperature, increased osmotic pressure, etc. Once in the VBNC state, they undergo various physiological, structural, and genetic alterations. These alterations result in reduced cell size, conversion from bacilli to coccid, thickened cell walls, and peptidoglycan gaining many cross links. Metabolic changes also occur that include reductions in growth, nutrient transport, and respiratory rate; biosynthesis of new protein, and ATP remaining at a constant level. It has been shown that in the VBNC state, some pathogens conserve their virulence properties. Gene expression continues in the VBNC cell. Nucleic acids remain intact in the early VBNC phase but they gradually undergo degradation with prolonged VBNC. Cytological methods such as direct viable count and reduction of tetrazolium salts, and molecular methods such as reverse transcription polymerase chain reaction and green fluorescent protein have been used for the study of VBNC. Resuscitation from VBNC state starts when the inducing factor(s is/are lifted. Factors that help the resuscitation of VBNC bacteria include addition of certain nutrients and chemicals, introduction of a few culturable cells into the VBNC cell population, and passage through the animal host. As virulence properties are sustained during the VBNC phase, special care must be paid when evaluating sterility of drinking water.

  6. Catecholate siderophores protect bacteria from pyochelin toxicity.

    Directory of Open Access Journals (Sweden)

    Conrado Adler

    Full Text Available Bacteria produce small molecule iron chelators, known as siderophores, to facilitate the acquisition of iron from the environment. The synthesis of more than one siderophore and the production of multiple siderophore uptake systems by a single bacterial species are common place. The selective advantages conferred by the multiplicity of siderophore synthesis remains poorly understood. However, there is growing evidence suggesting that siderophores may have other physiological roles besides their involvement in iron acquisition.Here we provide the first report that pyochelin displays antibiotic activity against some bacterial strains. Observation of differential sensitivity to pyochelin against a panel of bacteria provided the first indications that catecholate siderophores, produced by some bacteria, may have roles other than iron acquisition. A pattern emerged where only those strains able to make catecholate-type siderophores were resistant to pyochelin. We were able to associate pyochelin resistance to catecholate production by showing that pyochelin-resistant Escherichia coli became sensitive when biosynthesis of its catecholate siderophore enterobactin was impaired. As expected, supplementation with enterobactin conferred pyochelin resistance to the entE mutant. We observed that pyochelin-induced growth inhibition was independent of iron availability and was prevented by addition of the reducing agent ascorbic acid or by anaerobic incubation. Addition of pyochelin to E. coli increased the levels of reactive oxygen species (ROS while addition of ascorbic acid or enterobactin reduced them. In contrast, addition of the carboxylate-type siderophore, citrate, did not prevent pyochelin-induced ROS increases and their associated toxicity.We have shown that the catecholate siderophore enterobactin protects E. coli against the toxic effects of pyochelin by reducing ROS. Thus, it appears that catecholate siderophores can behave as protectors of

  7. Repair by genetic recombination in bacteria: overview

    International Nuclear Information System (INIS)

    Howard-Flanders, P.

    1975-01-01

    DNA molecules that have been damaged in both strands at the same level are not subject to repair by excision but instead can be repaired through recombination with homologous molecules. Examples of two-strand damage include postreplication gaps opposite pyrimidine dimers, two-strand breaks produced by x-rays, and chemically induced interstrand cross-links. In ultraviolet-irradiated bacteria, and newly synthesized DNA is of length equal to the interdimer spacing. With continued incubation, this low-molecular-weight DNA is joined into high-molecular-weight chains (postreplication repair), a process associated with sister exchanges in bacteria. Recombination is initiated by pyrimidine dimers opposite postreplication gaps and by interstrand cross-links that have been cut by excision enzymes. The free ends at the resulting gaps presumably initiate the exchanges. Postreplication repair in Escherichia coli occurs in recB - and recC - but is greatly slowed in recF - mutants. RecB and recC are the structural genes for exonuclease V, which digests two-stranded DNA by releasing oligonucleotides first from one strand and then from the other. The postreplication sister exchanges in ultraviolet-irradiated bacteria result in the distribution of pyrimidine dimers between parental and daughter strands, indicating that long exchanges involving both strands of each duplex occur. The R1 restriction endonuclease from E. coli has been used to cut the DNA of a bacterial drug-resistance transfer factor with one nuclease-sensitive site, and also DNA from the frog Xenopus enriched for ribosomal 18S and 28S genes. The fragments were annealed with the cut plasmid DNA and ligated, producing a new larger plasmid carrying the eukaryotic rDNA and able to infect and replicate in E. coli

  8. Close Encounters of Lymphoid Cells and Bacteria

    Science.gov (United States)

    Cruz-Adalia, Aranzazu; Veiga, Esteban

    2016-01-01

    During infections, the first reaction of the host against microbial pathogens is carried out by innate immune cells, which recognize conserved structures on pathogens, called pathogen-associated molecular patterns. Afterward, some of these innate cells can phagocytose and destroy the pathogens, secreting cytokines that would modulate the immune response to the challenge. This rapid response is normally followed by the adaptive immunity, more specific and essential for a complete pathogen clearance in many cases. Some innate immune cells, usually named antigen-presenting cells, such as macrophages or dendritic cells, are able to process internalized invaders and present their antigens to lymphocytes, triggering the adaptive immune response. Nevertheless, the traditional boundary of separated roles between innate and adaptive immunity has been blurred by several studies, showing that very specialized populations of lymphocytes (cells of the adaptive immunity) behave similarly to cells of the innate immunity. These “innate-like” lymphocytes include γδ T cells, invariant NKT cells, B-1 cells, mucosal-associated invariant T cells, marginal zone B cells, and innate response activator cells, and together with the newly described innate lymphoid cells are able to rapidly respond to bacterial infections. Strikingly, our recent data suggest that conventional CD4+ T cells, the paradigm of cells of the adaptive immunity, also present innate-like behavior, capturing bacteria in a process called transinfection. Transinfected CD4+ T cells digest internalized bacteria like professional phagocytes and secrete large amounts of proinflammatory cytokines, protecting for further bacterial challenges. In the present review, we will focus on the data showing such innate-like behavior of lymphocytes following bacteria encounter. PMID:27774092

  9. Resistência à mupirocina entre isolados de Staphylococcus aureus de profissionais de enfermagem Resistencia al mupirocin en cepas aisladas de Staphylococcus aureus de profesionales de enfermería Mupirocin-resistant Staphylococcus aureus in samples belonging to professional nurses

    Directory of Open Access Journals (Sweden)

    Josely Pinto de Moura

    2010-06-01

    Full Text Available OBJETIVOS: Avaliar a colonização por Staphylococcus aureus sensíveis e resistentes à meticilina na saliva de profissionais de enfermagem e o perfil de resistência à mupirocina. MÉTODOS: Foram coletadas três amostras da saliva de 356 (94,2% profissionais participantes da pesquisa, totalizando 1.068 amostras processadas. Todos os aspectos éticos foram contemplados. A análise microbiológica compreendeu a identificação fenotípica, segundo normas do Clinical and Laboratory Standards Institute. RESULTADOS: Foram obtidos 73 indivíduos colonizados por Staphylococcus aureus na primeira coleta, 48 na segunda e 37 na terceira, somando 158 isolados de Staphylococcus aureus. Desses, 24 (15,2% eram resistentes à oxacilina e 30 resistentes à mupirocina (18,9%. A resistência à mupirocina foi observada de forma pronunciada nos Staphylococcus aureus metacilina resistente (MRSA; dos 24 MRSA, 17 (70,8% apresentaram-se resistentes a este antimicrobiano. CONCLUSÃO: Os resultados indicaram que a resistência à mupirocina é um importante problema, pois esse antibiótico é um excelente aliado nas medidas de controle das infecções de serviços de saúde.OBJETIVOS: Evaluar la colonización por Staphylococcus aureus sensibles y resistentes al meticilín en la saliva de profesionales de enfermería y, reconocer el perfil de resistencia a la mupirocina. MÉTODOS: Fueron recolectadas tres muestras de saliva de 356 (94,2% profesionales participantes de la investigación, totalizando 1.068 muestras procesadas. Todos los aspectos éticos fueron contemplados. El análisis microbiológico comprendió la identificación fenotípica, según normas del Clinical and Laboratory Standards Institute. RESULTADOS: Fueron obtenidos 73 individuos colonizados por Staphylococcus aureus en la primera recolección, 48 en la segunda y 37 en la tercera, sumando 158 muestras aisladas de Staphylococcus aureus. De esas, 24 (15,2% eran resistentes a la oxacilina y 30

  10. Protocolo POG 9061 en la recaída aislada a sistema nervioso central en pacientes con diagnóstico de leucemia linfoide aguda. Resultados de una serie de casos en el Hospital Universitario de Santander POG 9061 protocol to treat isolated central nervous system recurrence in patients with acute lymphoid leukemia at Hospital Universitario de Santander

    Directory of Open Access Journals (Sweden)

    Ernesto Rueda

    2010-04-01

    Full Text Available Introducción: La leucemia linfoide aguda (LLA es la neoplasia más común en niños; el 5-10 % presentan recaídas a sistema nervioso central (SNC, un factor de mal pronóstico. Objetivo: Describir los resultados obtenidos en una unidad de oncología pediátrica con el protocolo POG 9061 modificado, en pacientes con LLA y recaída aislada a SNC. Metodología: Cohorte de los pacientes atendidos en el Hospital Universitario de Santander (HUS. Se estimó la sobrevida libre de evento (SLE y la sobrevida total (ST, así como las alteraciones resultantes del protocolo. Se incluyeron 15 pacientes atendidos entre enero/93 y marzo/07; el último diagnóstico de recaída al SNC se hizo en noviembre/04. Resultados: El 66,6 % de las recaídas se dieron antes de 18 meses luego de remitir la LLA. Dos pacientes abandonaron el protocolo, uno de los cuales falleció; dos o más fallecieron luego de terminar el protocolo. La ST a cinco años fue de 85,6 % (IC95 % 53,3-96,2, mientras que la SLE de 84,9 % (IC95 % 51,2-96,0 %. La complicación más frecuente fue mielosupresión; no hubo alteraciones de la función renal y solo una ligera elevación de las pruebas de función hepática. Las causas de hospitalización fueron principalmente infecciones. El coeficiente intelectual de los pacientes posterior a la aplicación del protocolo indicaba deficiencia leve en el 45,4 % de ellos. Conclusiones: La sobrevida, el tipo y la frecuencia de complicaciones, son similares a las encontradas a nivel mundial, lo que es relevante dada la alta proporción de pacientes con recaída precoz luego de remisión de la LLA. Salud UIS 2010; 42: 7-17Introduction: Acute lymphoblastic leukemia (ALL is the most frequent neoplasm in children. Relapses to central nervous system (CNS Appears in 5-10 % of the ALL patients and is a bad prognostic factor. Objective: To describe the results obtained with modified POG 9061 protocol in a pediatric oncology unit. Methodology: Survival analysis was

  11. Electroactive biofilms of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina; Moura, Jose J.G.

    2008-01-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m -2 that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces

  12. Isolation and biochemical characterizations of the bacteria ...

    African Journals Online (AJOL)

    These isolates yielded off white convex colonies on potato dextrose agar (PDA) media at 29°C with 1.7 to 1.9 mm diameter and were yellow on yeast extract dextrose chalk agar (YDC) media at 27°C with 1.8 to 2.0 mm diameter. The bacteria were rod shape measuring 0.5 to 0.6 × 1.4 to 1.6 μm on PDA and 0.6 to 0.7 × 1.5 to ...

  13. Bioluminescent bacteria: lux genes as environmental biosensors

    Directory of Open Access Journals (Sweden)

    Nunes-Halldorson Vânia da Silva

    2003-01-01

    Full Text Available 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 environmental studies, with special emphasis on the Microtox toxicity bioassay. Also, the general ecological significance of bioluminescence will be addressed.

  14. Polymorphic transformation of helical flagella of bacteria

    Science.gov (United States)

    Lim, Sookkyung; Howard Berg Collaboration; William Ko Collaboration; Yongsam Kim Collaboration; Wanho Lee Collaboration; Charles Peskin Collaboration

    2016-11-01

    Bacteria such as E. coli swim in an aqueous environment by utilizing the rotation of flagellar motors and alternate two modes of motility, runs and tumbles. Runs are steady forward swimming driven by bundles of flagellar filaments whose motors are turning CCW; tumbles involve a reorientation of the direction of swimming triggered by motor reversals. During tumbling, the helical flagellum undergoes polymorphic transformations, which is a local change in helical pitch, helical radius, and handedness. In this work, we investigate the underlying mechanism of structural conformation and how this polymorphic transition plays a role in bacterial swimming. National Science Foundation.

  15. Ethylene-producing bacteria that ripen fruit.

    Science.gov (United States)

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples.

  16. Are Bacteria more dangerous in space?

    International Nuclear Information System (INIS)

    Leys, N.; Baatout, S.

    2010-01-01

    With a mission to Mars and a permanent base on the moon as the ultimate dream, space travel is continually pushing back the frontiers. But long space missions present great challenges for science, for example in the field of microbiology. Together with the European Space Agency (ESA), SCK-CEN is studying the effects of space travel conditions on the behaviour of bacteria. In 2009 the SCK-CEN experts completed four innovative research projects at the cutting edge of microbiology, radiation sciences and space travel.

  17. Electroactive biofilms of sulphate reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Moura, Jose J.G. [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)], E-mail: jose.moura@dq.fct.unl.pt

    2008-12-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m{sup -2} that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces.

  18. 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...... bacterial lipases are particularly abundant at sites of infection. Herein it is shown how active or proactive compounds attached to polymeric surfaces using lipase‐sensitive linkages, such as fatty acid esters or anhydrides, may be released in response to infection. Proof‐of‐concept of the responsive...

  19. Anaerobic bacteria as producers of antibiotics.

    Science.gov (United States)

    Behnken, Swantje; Hertweck, Christian

    2012-10-01

    Anaerobic bacteria are the oldest terrestrial creatures. They occur ubiquitously in soil and in the intestine of higher organisms and play a major role in human health, ecology, and industry. However, until lately no antibiotic or any other secondary metabolite has been known from anaerobes. Mining the genome sequences of Clostridium spp. has revealed a high prevalence of putative biosynthesis genes (PKS and NRPS), and only recently the first antibiotic from the anaerobic world, closthioamide, has been isolated from the cellulose degrading bacterium Clostridium cellulolyticum. The successful genetic induction of antibiotic biosynthesis in an anaerobe encourages further investigations of obligate anaerobes to tap their hidden biosynthetic potential.

  20. Capacidade aerobia de futebolistas profissionais de altitude durante o periodo competitivo da cidade de Arequipa-Peru

    OpenAIRE

    Alejandro Inostroza Aeloiza

    2004-01-01

    Resumo: O objetivo do presente estudo foi de descrever e analisar a capacidade aeróbia de futebolistas profissionais de altitude durante o período competitivo, onde a seleção da amostra foi de tipo não-probabilístico 27 jogadores, para tal efeito, foram mensuradas as variáveis de massa corporal, estatura, quatro dobras cutâneas (triciptal, subescapular, supra- Ilíaca, e panturrilha), e para a capacidade aeróbia progressiva foi utilizado o teste físico de (corrida de ida e volta de 20m) de Nav...

  1. Bacteria in atmospheric waters: Detection, characteristics and implications

    Science.gov (United States)

    Hu, Wei; Niu, Hongya; Murata, Kotaro; Wu, Zhijun; Hu, Min; Kojima, Tomoko; Zhang, Daizhou

    2018-04-01

    In this review paper, we synthesize the current knowledges about bacteria in atmospheric waters, e.g., cloud, fog, rain, and snow, most of which were obtained very recently. First, we briefly describe the importance of bacteria in atmospheric waters, i.e., the essentiality of studying bacteria in atmospheric waters in understanding aerosol-cloud-precipitation-climate interactions in the Earth system. Next, approaches to collect atmospheric water samples for the detection of bacteria and methods to identify the bacteria are summarized and compared. Then the available data on the abundance, viability and community composition of bacteria in atmospheric waters are summarized. The average bacterial concentration in cloud water was usually on the order 104-105 cells mL-1, while that in precipitation on the order 103-104 cells mL-1. Most of the bacteria were viable or metabolically active. Their community composition was highly diverse and differed at various sites. Factors potentially influencing the bacteria, e.g., air pollution levels and sources, meteorological conditions, seasonal effect, and physicochemical properties of atmospheric waters, are described. After that, the implications of bacteria present in atmospheric waters, including their effect on nucleation in clouds, atmospheric chemistry, ecosystems and public health, are briefly discussed. Finally, based on the current knowledges on bacteria in atmospheric waters, which in fact remains largely unknown, we give perspectives that should be paid attention to in future studies.

  2. The effect of lactic acid bacteria on cocoa bean fermentation.

    Science.gov (United States)

    Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

    2015-07-16

    Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

  3. Metabolism of polychlorinated biphenyls by marine bacteria

    International Nuclear Information System (INIS)

    Carey, A.E.; Harvey, G.R.

    1978-01-01

    There have been no reports of laboratory studies of PCB metabolism by marine organisms. A few workers have analyzed marine animals for products of PCB metabolism. A search for hydroxylated PCBs in marine fish proved inconclusive. Phenolic metabolites of PCBs have been identified in seals and guillemot. PCBs that had been hydroxylated and excreted by marine organisms would most likely be found in the sediments, so in our laboratory we conducted a search for these compounds in marine sediments. Two kilograms of organic-rich surface sediment from Buzzards Bay, Massachusetts, were extracted. The phenolic fraction was isolated and analyzed by gas chromatography-mass spectrometry (GC-MS). Neither wide mass scans nor selected mass searches produced any evidence of hydroxylated PCB derivatives. It was felt that if any marine organisms were capable of metabolism of PCBs, some marine bacteria should have that capability. Thus a series of laboratory experiments was conducted to test this possibility. Reported here is the finding of PCB metabolism by marine bacteria in batch culture

  4. Long-term preservation of anammox bacteria.

    Science.gov (United States)

    Rothrock, Michael J; Vanotti, Matias B; Szögi, Ariel A; Gonzalez, Maria Cruz Garcia; Fujii, Takao

    2011-10-01

    Deposit of useful microorganisms in culture collections requires long-term preservation and successful reactivation techniques. The goal of this study was to develop a simple preservation protocol for the long-term storage and reactivation of the anammox biomass. To achieve this, anammox biomass was frozen or lyophilized at two different freezing temperatures (-60°C and in liquid nitrogen (-200°C)) in skim milk media (with and without glycerol), and the reactivation of anammox activity was monitored after a 4-month storage period. Of the different preservation treatments tested, only anammox biomass preserved via freezing in liquid nitrogen followed by lyophilization in skim milk media without glycerol achieved stoichiometric ratios for the anammox reaction similar to the biomass in both the parent bioreactor and in the freshly harvested control treatment. A freezing temperature of -60°C alone, or in conjunction with lyophilization, resulted in the partial recovery of the anammox bacteria, with an equal mixture of anammox and nitrifying bacteria in the reactivated biomass. To our knowledge, this is the first report of the successful reactivation of anammox biomass preserved via sub-zero freezing and/or lyophilization. The simple preservation protocol developed from this study could be beneficial to accelerate the integration of anammox-based processes into current treatment systems through a highly efficient starting anammox biomass.

  5. Bioactivation of Phytoestrogens: Intestinal Bacteria and Health.

    Science.gov (United States)

    Landete, J M; Arqués, J; Medina, M; Gaya, P; de Las Rivas, B; Muñoz, R

    2016-08-17

    Phytoestrogens are polyphenols similar to human estrogens found in plants or derived from plant precursors. Phytoestrogens are found in high concentration in soya, flaxseed and other seeds, fruits, vegetables, cereals, tea, chocolate, etc. They comprise several classes of chemical compounds (stilbenes, coumestans, isoflavones, ellagitannins, and lignans) which are structurally similar to endogenous estrogens but which can have both estrogenic and antiestrogenic effects. Although epidemiological and experimental evidence indicates that intake of phytoestrogens in foods may be protective against certain chronic diseases, discrepancies have been observed between in vivo and in vitro experiments. The microbial transformations have not been reported so far in stilbenes and coumestans. However, isoflavones, ellagitanins, and lignans are metabolized by intestinal bacteria to produce equol, urolithins, and enterolignans, respectively. Equol, urolithin, and enterolignans are more bioavailable, and have more estrogenic/antiestrogenic and antioxidant activity than their precursors. Moreover, equol, urolithins and enterolignans have anti-inflammatory effects and induce antiproliferative and apoptosis-inducing activities. The transformation of isoflavones, ellagitanins, and lignans by intestinal microbiota is essential to be protective against certain chronic diseases, as cancer, cardiovascular disease, osteoporosis, and menopausal symptoms. Bioavailability, bioactivity, and health effects of dietary phytoestrogens are strongly determined by the intestinal bacteria of each individual.

  6. Inoculation of sugarcane with diazotrophic bacteria

    Directory of Open Access Journals (Sweden)

    Nivaldo Schultz

    2014-04-01

    Full Text Available The sugarcane industry, a strategic crop in Brazil, requires technological improvements in production efficiency to increase the crop energy balance. Among the various currently studied alternatives, inoculation with diazotrophic bacteria proved to be a technology with great potential. In this context, the efficiency of a mixture of bacterial inoculant was evaluated with regard to the agronomic performance and N nutrition of sugarcane. The experiment was carried out on an experimental field of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, using a randomized block, 2 × 3 factorial design (two varieties and three treatments with four replications, totaling 24 plots. The varieties RB867515 and RB72454 were tested in treatments consisting of: inoculation with diazotrophic bacteria, N-fertilized control with 120 kg ha-1 N and absolute control (no inoculation and no N fertilizer. The inoculum was composed of five strains of five diazotrophic species. The yield, dry matter accumulation, total N in the shoot dry matter and the contribution of N by biological fixation were evaluated, using the natural 15N abundance in non-inoculated sugarcane as reference. The bacterial inoculant increased the stalk yield of variety RB72454 similarly to fertilization with 120 kg ha-1 N in the harvests of plant-cane and first ratoon crops, however the contribution of biological N fixation was unchanged by inoculation, indicating that the benefits of the inoculant in sugarcane may have resulted from plant growth promotion.

  7. Beneficial effects of antioxidative lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Hisako Nakagawa

    2017-01-01

    Full Text Available Oxidative stress is caused by exposure to reactive oxygen intermediates. The oxidative damage of cell components such as proteins, lipids, and nucleic acids one of the important factors associated with diabetes mellitus, cancers and cardiovascular diseases. This occurs as a result of imbalance between the generations of oxygen derived radicals and the organism’s antioxidant potential. The amount of oxidative damage increases as an organism ages and is postulated to be a major causal factor of senescence. To date, many studies have focused on food sources, nutrients, and components that exert antioxidant activity in worms, flies, mice, and humans. Probiotics, live microorganisms that when administered in adequate amounts provide many beneficial effects on the human health, have been attracting growing interest for their health-promoting effects, and have often been administered in fermented milk products. In particular, lactic acid bacteria (LAB are known to conferre physiologic benefits. Many studies have indicated the antioxidative activity of LAB. Here we review that the effects of lactic acid bacteria to respond to oxidative stress, is connected to oxidative-stress related disease and aging.

  8. Starvation-survival of subsurface bacteria

    International Nuclear Information System (INIS)

    Magill, N.G.

    1988-01-01

    The ability of four subsurface isolates to survive starvation was examined and the results were compared to survival curves obtained for Escherichia coli B and Serratia marcescens. To examine the starvation-survival phenomenon further, several experimental parameters including nutritional history, initial cell density, growth phase, temperature of growth and starvation, and aeration. Nutritional history, initial cell density, and growth phases of the cells had some effect on the ability of these bacteria to survive whereas temperature and limited aeration had no effect under the conditions tested. No conditions were found where E. coli B or Serratia marcescens died rapidly or where less than 10% of the original cell number of viable cells remained. Because the apparent survival of these bacteria may be due to cryptic growth, cross-feeding experiments with 14 C-labeled cells and unlabeled cells were carried out with E. coli B and Pseudomonas Lula V. Leaked extracellular 14 C-compounds were not used for growth or maintenance energy, and were not taken up by either bacterium. Cryptic growth did not occur; the cells were truly starving under the experimental conditions used

  9. Identification of Lactic Acid Bacteria and Propionic Acid Bacteria using FTIR Spectroscopy and Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Beata Nalepa

    2012-01-01

    Full Text Available In the present study, lactic acid bacteria and propionic acid bacteria have been identified at the genus level with the use of artificial neural networks (ANNs and Fourier transform infrared spectroscopy (FTIR. Bacterial strains of the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Propionibacterium were analyzed since they deliver health benefits and are routinely used in the food processing industry. The correctness of bacterial identification by ANNs and FTIR was evaluated at two stages. At first stage, ANNs were tested based on the spectra of 66 reference bacterial strains. At second stage, the evaluation involved 286 spectra of bacterial strains isolated from food products, deposited in our laboratory collection, and identified by genus-specific PCR. ANNs were developed based on the spectra and their first derivatives. The most satisfactory results were reported for the probabilistic neural network, which was built using a combination of W5W4W3 spectral ranges. This network correctly identified the genus of 95 % of the lactic acid bacteria and propionic acid bacteria strains analyzed.

  10. Sulphur bacteria mediated formation of Palaeoproterozoic phosphorites

    Science.gov (United States)

    Joosu, Lauri; Lepland, Aivo; Kirsimäe, Kalle

    2014-05-01

    Modern phosphorite formation is typically associated with high productivity in upwelling areas where apatite (Ca-phosphate) precipitation is mediated by sulphur oxidising bacteria [1]. They inhabit the oxic/anoxic interface within the upper few centimetres of sediment column, accumulating phosphate in their cells under oxic conditions and releasing it rapidly when conditions become anoxic. Sulphur bacteria are known to live in close association with a consortium of anaerobic methane oxidising archaea and syntrophic sulphate-reducing bacteria. Paleoproterozoic, c. 2.0 Ga Zaonega Formation in Karelia, Russia contains several P-rich intervals in the upper part of 1500 m thick succession of organic-rich sedimentary rocks interlayered with mafic tuffs and lavas. Apatite in these P-rich intervals forms impure laminae, lenses and round-oval nodules which diameters typically range from 300 to 1000 μm. Individual apatite particles in P-rich laminae and nodules commonly occur as cylinders that are 1-8 μm long and have diameters of 0.5-4 μm. Cross-sections of best preserved cylindrical apatite particles reveal a thin outer rim whereas the internal parts consist of small anhedral elongated crystallites, intergrown with carbonaceous material. During recrystallization the outer rim thickens towards interior and cylinders may attain hexagonal crystal habit, but their size and shape remains largely unchanged [2]. The sizes of Zaonega nodules are similar to giant sulphide-oxidising bacteria known from modern and ancient settings [3, 4]. Individual apatite cylinders and aggregates have shapes and sizes similar to the methanotrophic archaea that inhabit microbial mats in modern seep/vent areas where they operate in close associations with sulphur-oxidising microbial communities [5]. Seep/vent influence during the Zaonega phosphogenesis is indicated by variable, though positive Eu anomaly, expected in magmatically active sedimentary environment experiencing several lava flows

  11. Antibacterial Activities of Endophytic Bacteria Isolated from Taxus brevifolia Against Foodborne Pathogenic Bacteria.

    Science.gov (United States)

    Islam, Nurul; Choi, Jaehyuk; Baek, Kwang-Hyun

    2018-05-01

    Endophytes are a potential source of novel bioactive compounds with medicinal properties. In this study, 41 endophytic bacteria (EB) were isolated from tissues of a medicinally important plant Taxus brevifolia (Pacific yew). The objective was to screen all the EB isolates for their antibacterial effects against five foodborne pathogenic bacteria: Bacillus cereus ATCC10876, Staphylococcus aureus ATCC12600, Listeria monocytogenes ATCC19115, Escherichia coli ATCC43890, and Salmonella Typhimurium ATCC19585. Among the EB isolates, T. brevifolia seed (TbS)-8, T. brevifolia fleshy part of fruit (TbFl)-10, T. brevifolia leaf (TbL)-22, TbS-29, and TbL-34 exerted significant antibacterial activity against the tested foodborne pathogens. Especially TbFl-10 showed the highest antibacterial activity against all the tested bacteria and was identified as Paenibacillus kribbensis (Pk). Furthermore, an ethyl acetate extract of Pk-TbFl-10 possessed antibacterial activities against the tested five foodborne pathogenic bacteria, with zones of inhibition from 15.71 ± 2.85 to 13.01 ± 2.12 mm. Scanning electron microscopy analysis revealed ruptured, lysed, shrunk, and swollen cells of all the tested foodborne pathogens treated with the ethyl acetate extract of Pk-TbFl-10, suggesting that a metabolite(s) of Pk-TbFl-10 penetrates the cell membrane and causes cell lysis leading to cell death. Our results indicate that Pk-TbFl-10 isolated from T. brevifolia can serve as a novel source of natural antibacterial agents against foodborne pathogenic bacteria, with potential applications in the pharmaceutical industry.

  12. [Effects of transgenic Bt + CpTI cotton on rhizosphere bacteria and ammonia oxidizing bacteria population].

    Science.gov (United States)

    Dong, Lianhua; Meng, Ying; Wang, Jing

    2014-03-04

    The effect of transgenic cotton on the rhizosphere bacteria can be important to the risk assessment for the genetically modified crops. We studied the rhizosphere microbial community with cultivating genetically modified cotton. The effects of transgenic Bt + CpTI Cotton (SGK321) and its receptor cotton (SY321) on rhizosphere total bacteria and ammonia oxidizing bacteria population size were studied by using droplet digital PCR. We collected rhizosphere soil before cotton planting and along with the cotton growth stage (squaring stage, flowering stage, belling stage and boll opening stage). There was no significant change on the total bacterial population between the transgenic cotton and the receptor cotton along with the growth stage. However, the abundance of ammonia oxidizing bacteria (AOB) in both type of cottons showed significant difference between different growth stages, and the variation tendency was different. In squaring stage, the numbers of AOB in rhizosphere of SY321 and SGK321 increased 4 and 2 times, respectively. In flowering stage, AOB number in rhizosphere of SY321 significantly decreased to be 5.96 x 10(5) copies/g dry soil, however, that of SGK321 increased to be 1.25 x 10(6) copies/g dry soil. In belling stage, AOB number of SY321 greatly increased to be 1.49 x 10(6) copies/g dry soil, but no significant change was observed for AOB number of SGK321. In boll opening stage, both AOB number of SY321 and SGK321 clearly decreased and they were significantly different from each other. Compared to the non-genetically modified cotton, the change in abundance of ammonia oxidizing bacteria was slightly smooth in the transgenic cotton. Not only the cotton growth stage but also the cotton type caused this difference. The transgenic cotton can slow down the speed of ammonia transformation through impacting the number of AOB, which is advantageous for plant growth.

  13. Reactivity of the Bacteria-Water Interface: Linking Nutrient Availability to Bacteria-Metal Interactions

    Science.gov (United States)

    Fowle, D. A.; Daughney, C. J.; Riley, J. L.

    2002-12-01

    Identifying and quantifying the controls on metal mobilities in geologic systems is critical in order to understand processes such as global element cycling, metal transport in near-surface water-rock systems, sedimentary diagenesis, and mineral formation. Bacteria are ubiquitous in near-surface water-rock systems, and numerous laboratory and field studies have demonstrated that bacteria can facilitate the formation and dissolution of minerals, and enhance or inhibit contaminant transport. However, despite the growing evidence that bacteria play a key role in many geologic processes in low temperature systems, our understanding of the influence of the local nutrient dynamics of the system of interest on bacteria-metal interactions is limited. Here we present data demonstrating the effectiveness of coupling laboratory experiments with geochemical modeling to isolate the effect of nutrient availability on bacterially mediated proton and metal adsorption reactions. Experimental studies of metal-bacteria interactions were conducted in batch reactors as a function of pH, and solid-solute interactions after growth in a variety of defined and undefined media. Media nutrient composition (C,N,P) was quantified before and after harvesting the cells. Surface complexation models (SCM) for the adsorption reactions were developed by combining sorption data with the results of acid-base titrations, and in some cases zeta potential titrations of the bacterial surface. Our results indicate a clear change in both buffering potential and metal binding capacity of the cell walls of Bacillus subtilis as a function of initial media conditions. Combining current studies with our past studies on the effects of growth phase and others work on temperature dependence on metal adsorption we hope to develop a holistic surface complexation model for quantifying bacterial effects on metal mass transfer in many geologic systems.

  14. Reducing gas content of coal deposits by means of bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska-Lipowa, A A; Kozlowski, B

    1981-07-01

    This paper discusses the results of experiments carried out in Poland under laboratory conditions on efficiency of methane control using bacteria from Methanosarcina and Methanomonas groups. Malashenko and Whittenburry culture mediums were used. Bacteria growth in an atmosphere of air and methane (48.2%, 8.6% and 5.21%) was observed. Temperature ranged from 19 to 20 C. Investigations show that the bacteria are characterized by high oxidation activity. Depending on methane concentration in the air the bacteria consume from 75% to 100% of methane during biosynthesis. The bacteria reduce methane and oxygen content and increase carbon dioxide content in the air. Using bacteria methane concentration in the air was reduced from 48.2% to 12.3%, from 8.6% to 0.0% and from 5.21% to 0.01%. (7 refs.) (In Polish)

  15. Influence of irradiation of bacteria on their thermoresistance

    International Nuclear Information System (INIS)

    Szulc, M.; Stefaniakowa, A.; Tropilo, J.; Stanczak, B.; Peconek, J.; Mierzewska, H.; Bielecka, J.

    1979-01-01

    The influence of x-radiation on thermoresistance of bacteria was determined. The studies were carried out on: E. coli, Pr. vulgaris, S. typhimurium, Staph. aureus and Str. faecalis. The bacteria were irradiated in PBS (physiological buffer solution) and in broth (containing about 1% of protein) with x-rays at radium absorbed doses of 100, 1000, 5000 and 10 000, which was followed immediately by heating at temperatures causing death of part of the bacteria. The results obtained indicate that irradiation of bacteria with small x-ray doses distinctly decreases their thermoresistance. Synergetic action of irradiation and heating of bacteria was observed, increasing with increased irradiation dose. The greatest changes of thermoresistance occurred with Pr. vulgaris, the smallest with S. typhimurium. Thermoresistance of bacteria decreased more strongly on their irradiation in protein-free medium (PBS). (author)

  16. Deployable micro-traps to sequester motile bacteria

    Science.gov (United States)

    di Giacomo, Raffaele; Krödel, Sebastian; Maresca, Bruno; Benzoni, Patrizia; Rusconi, Roberto; Stocker, Roman; Daraio, Chiara

    2017-04-01

    The development of strategies to reduce the load of unwanted bacteria is a fundamental challenge in industrial processing, environmental sciences and medical applications. Here, we report a new method to sequester motile bacteria from a liquid, based on passive, deployable micro-traps that confine bacteria using micro-funnels that open into trapping chambers. Even in low concentrations, micro-traps afford a 70% reduction in the amount of bacteria in a liquid sample, with a potential to reach >90% as shown by modelling improved geometries. This work introduces a new approach to contain the growth of bacteria without chemical means, an advantage of particular importance given the alarming growth of pan-drug-resistant bacteria.

  17. Biotechnological applications of acetic acid bacteria.

    Science.gov (United States)

    Raspor, Peter; Goranovic, Dusan

    2008-01-01

    The acetic acid bacteria (AAB) have important roles in food and beverage production, as well as in the bioproduction of industrial chemicals. In recent years, there have been major advances in understanding their taxonomy, molecular biology, and physiology, and in methods for their isolation and identification. AAB are obligate aerobes that oxidize sugars, sugar alcohols, and ethanol with the production of acetic acid as the major end product. This special type of metabolism differentiates them from all other bacteria. Recently, the AAB taxonomy has been strongly rearranged as new techniques using 16S rRNA sequence analysis have been introduced. Currently, the AAB are classified in ten genera in the family Acetobacteriaceae. AAB can not only play a positive role in the production of selected foods and beverages, but they can also spoil other foods and beverages. AAB occur in sugar- and alcohol-enriched environments. The difficulty of cultivation of AAB on semisolid media in the past resulted in poor knowledge of the species present in industrial processes. The first step of acetic acid production is the conversion of ethanol from a carbohydrate carried out by yeasts, and the second step is the oxidation of ethanol to acetic acid carried out by AAB. Vinegar is traditionally the product of acetous fermentation of natural alcoholic substrates. Depending on the substrate, vinegars can be classified as fruit, starch, or spirit substrate vinegars. Although a variety of bacteria can produce acetic acid, mostly members of Acetobacter, Gluconacetobacter, and Gluconobacter are used commercially. Industrial vinegar manufacturing processes fall into three main categories: slow processes, quick processes, and submerged processes. AAB also play an important role in cocoa production, which represents a significant means of income for some countries. Microbial cellulose, produced by AAB, possesses some excellent physical properties and has potential for many applications. Other

  18. Transmission of Nephridial Bacteria of the Earthworm Eisenia fetida

    OpenAIRE

    Davidson, Seana K.; Stahl, David A.

    2006-01-01

    The lumbricid earthworms (annelid family Lumbricidae) harbor gram-negative bacteria in their excretory organs, the nephridia. Comparative 16S rRNA gene sequencing of bacteria associated with the nephridia of several earthworm species has shown that each species of worm harbors a distinct bacterial species and that the bacteria from different species form a monophyletic cluster within the genus Acidovorax, suggesting that there is a specific association resulting from radiation from a common b...

  19. Heme and menaquinone induced electron transport in lactic acid bacteria

    OpenAIRE

    Brooijmans, Rob; Smit, Bart; Santos, Filipe; van Riel, Jan; de Vos, Willem M; Hugenholtz, Jeroen

    2009-01-01

    Abstract Background For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Results Heme- (and menaquinone) stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacill...

  20. Biodegradation of endosulfan by mixed bacteria culture strains of ...

    African Journals Online (AJOL)

    Biodegradation of endosulfan by mixed bacteria culture strains of Pseudomonas aeruginosa and Staphylococcus aureus. Nsidibeabasi Calvin Nwokem, Calvin Onyedika Nwokem, Casmir Emmanuel Gimba, Beatrice Nkiruka Iwuala ...

  1. Effect of radiation on activity of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Agaev, N.M.; Smorodin, A.E.; Gusejnov, M.M.

    1985-01-01

    The effect of γ-radiation on activity of sulphate reducing bacteria has been studied. Concentration of biogenic hydrogen, generated in the medium, is the main criterion, characterizing corrosion activity of the bacteria studied. The developed method of suppression of active development of sulfate reducing bacteria considerably reduces, and at lethal doses of γ-radiation eliminates altogether the bacteria activity and formation of the main corrosion agent-hydrogen sulphide-in the medium and that, in its turn, liquidates hydrogen sulphide corrosion

  2. Characterization of Bacteria Associated with Pinewood Nematode Bursaphelenchus xylophilus

    Science.gov (United States)

    Vicente, Claudia S. L.; Nascimento, Francisco; Espada, Margarida; Barbosa, Pedro; Mota, Manuel; Glick, Bernard R.; Oliveira, Solange

    2012-01-01

    Pine wilt disease (PWD) is a complex disease integrating three major agents: the pathogenic agent, the pinewood nematode Bursaphelenchus xylophilus; the insect-vector Monochamus spp.; and the host pine tree, Pinus sp. Since the early 80's, the notion that another pathogenic agent, namely bacteria, may play a role in PWD has been gaining traction, however the role of bacteria in PWD is still unknown. The present work supports the possibility that some B. xylophilus-associated bacteria may play a significant role in the development of this disease. This is inferred as a consequence of: (i) the phenotypic characterization of a collection of 35 isolates of B. xylophilus-associated bacteria, in different tests broadly used to test plant pathogenic and plant growth promoting bacteria, and (ii) greenhouse experiments that infer the pathogenicity of these bacteria in maritime pine, Pinus pinaster. The results illustrate the presence of a heterogeneous microbial community associated with B. xylophilus and the traits exhibited by at least, some of these bacteria, appear to be related to PWD symptoms. The inoculation of four specific B. xylophilus-associated bacteria isolates in P. pinaster seedlings resulted in the development of some PWD symptoms suggesting that these bacteria likely play an active role with B. xylophilus in PWD. PMID:23091599

  3. Characterization of carbofuran-degrading bacteria isolated from ...

    African Journals Online (AJOL)

    Workstation

    Key words: Pesticides, carbofuran, methomyl, biodegradation, bacteria. INTRODUCTION .... polymerase chain reaction (PCR) amplification and partial sequence analysis of ..... Beutel KK (1986). Chlorinated hydrocarbon, In W. Gerhartz (ed.),.

  4. Investigation of IR absorption spectra of oral cavity bacteria

    Science.gov (United States)

    Belikov, Andrei V.; Altshuler, Gregory B.; Moroz, Boris T.; Pavlovskaya, Irina V.

    1996-12-01

    The results of comparative investigation for IR and visual absorption spectra of oral cavity bacteria are represented by this paper. There are also shown the main differences in absorption spectra of such pure bacteria cultures as : E- coli, Candida, Staph, Epidermidis, and absorption spectra of bacteria colonies cultured in tooth root canals suspected to harbour several endodontical problems. The results of experimental research targeted to investigate an effect of such combined YAG:Nd and YAG:Cr; Tm; Ho laser parameters like: wavelength, energy density, average power and etc., to oral cavity bacteria deactivation are given finally.

  5. Physical mode of bacteria and virus coevolution

    Science.gov (United States)

    Han, Pu; Niestemski, Liang; Deem, Michael

    2013-03-01

    Single-cell hosts such as bacteria or archaea possess an adaptive, heritable immune system that protects them from viral invasion. This system, known as the CRISPR-Cas system, allows the host to recognize and incorporate short foreign DNA or RNA sequences from viruses or plasmids. The sequences form what are called ``spacers'' in the CRISPR. Spacers in the CRISPR loci provide a record of the host and predator coevolution history. We develop a physical model to study the dynamics of this coevolution due to immune pressure. Hosts and viruses reproduce, die, and evolve due to viral infection pressure, host immune pressure, and mutation. We will discuss the differing effects of point mutation and recombination on CRISPR evolution. We will also discuss the effect of different spacer deletion mechanisms. We will describe population structure of hosts and viruses, how spacer diversity depends on position within CRISPR, and match of the CRISPR spacers to the virus population.

  6. Streptomyces bacteria as potential probiotics in aquaculture

    Directory of Open Access Journals (Sweden)

    Tan Loh eTeng Hern

    2016-02-01

    Full Text Available In response to the increased seafood demand from the ever-going human population, aquaculture has become the fastest growing animal food-producing sector. However, the indiscriminate use of antibiotics as a biological control agents for fish pathogens has led to the emergence of antibiotic resistance bacteria. Probiotics are defined as living microbial supplement that exert beneficial effects on hosts as well as improvement of environmental parameters. Probiotics have been proven to be effective in improving the growth, survival and health status of the aquatic livestock. This review aims to highlight the genus Streptomyces can be a good candidate for probiotics in aquaculture. Studies showed that the feed supplemented with Streptomyces could protect fish and shrimp from pathogens as well as increase the growth of the aquatic organisms. Furthermore, the limitations of Streptomyces as probiotics in aquaculture is also highlighted and solutions are discussed to these limitations.

  7. [Antimicrobial susceptibility testing of anaerobic bacteria].

    Science.gov (United States)

    García-Sánchez, José E; García-Sánchez, Enrique; García-García, María Inmaculada

    2014-02-01

    The anaerobic bacteria resistance to antibiotics is increasing, and even has appeared against the most active of those, like metronidazol and carbapenems. This fact forces to make and periodical sensibility tests -at least in the most aggressive and virulent species, in cases that they are isolated from life locations and in the absence of therapeutic response- to check the local sensibility and to establish suitable empiric therapies, all based on multicentric studies carried out in order to this or well to check the activity of new antibiotics. For the laboratory routine, the easiest sensibility method is the E-test/MIC evaluator. Another alternative is microdilution, that's only normalized for Bacteroides. There are preliminary facts that allow the use of disc diffusion method in some species of Bacteroides and Clostridium. For the temporal and multicentric studies, the procedure is dilution in agar plate, the reference method. Copyright © 2014 Elsevier España, S.L. All rights reserved.

  8. REGEN: Ancestral Genome Reconstruction for Bacteria

    Directory of Open Access Journals (Sweden)

    João C. Setubal

    2012-07-01

    Full Text Available Ancestral genome reconstruction can be understood as a phylogenetic study with more details than a traditional phylogenetic tree reconstruction. We present a new computational system called REGEN for ancestral bacterial genome reconstruction at both the gene and replicon levels. REGEN reconstructs gene content, contiguous gene runs, and replicon structure for each ancestral genome. Along each branch of the phylogenetic tree, REGEN infers evolutionary events, including gene creation and deletion and replicon fission and fusion. The reconstruction can be performed by either a maximum parsimony or a maximum likelihood method. Gene content reconstruction is based on the concept of neighboring gene pairs. REGEN was designed to be used with any set of genomes that are sufficiently related, which will usually be the case for bacteria within the same taxonomic order. We evaluated REGEN using simulated genomes and genomes in the Rhizobiales order.

  9. Synthesis of Metal Nanoparticles by Bacteria

    Directory of Open Access Journals (Sweden)

    Fikriye Alev Akçay

    2018-04-01

    Full Text Available Metal particles reduced to nano size by nanotechnological methods are confronted in many different fields such as biomedical and physicochemical, pharmaceutical, electric-electronic, automotive and food industries. Nanoparticles can be produced using chemical, physical and biological methods, of which chemical processes are in common use. However, physical and chemical methods are not environmentally friendly and economical because they require the use of high temperature, high pressure and toxic chemicals. For this reason, interest in the production of metal nanoparticles by biological methods, also called green technology, an environmentally friendly and sustainable approach, has increased in recent years. With some plant extracts and intracellular and extracellular secretions of microorganisms, some reduction reactions take place and metal nanoparticles are produced. Bacteria have been actively involved in nanotechnology in recent years due to their diversity in nature, their ease of isolation, and ease of nanoparticle synthesis. In this article, production and application of metal nanoparticles by using bacterial methods have been reviewed.

  10. Acetic Acid Bacteria as Symbionts of Insects

    KAUST Repository

    Crotti, Elena; Chouaia, Bessem; Alma, Alberto; Favia, Guido; Bandi, Claudio; Bourtzis, Kostas; Daffonchio, Daniele

    2016-01-01

    Acetic acid bacteria (AAB) are being increasingly described as associating with different insect species that rely on sugar-based diets. AAB have been found in several insect orders, among them Diptera, Hemiptera, and Hymenoptera, including several vectors of plant, animal, and human diseases. AAB have been shown to associate with the epithelia of different organs of the host, they are able to move within the insect’s body and to be transmitted horizontally and vertically. Here, we review the ecology of AAB and examine their relationships with different insect models including mosquitoes, leafhoppers, and honey bees. We also discuss the potential use of AAB in symbiont-based control strategies, such as “Trojan-horse” agents, to block the transmission of vector-borne diseases.

  11. Laser-induced fluorescence imaging of bacteria

    Science.gov (United States)

    Hilton, Peter J.

    1998-12-01

    This paper outlines a method for optically detecting bacteria on various backgrounds, such as meat, by imaging their laser induced auto-fluorescence response. This method can potentially operate in real-time, which is many times faster than current bacterial detection methods, which require culturing of bacterial samples. This paper describes the imaging technique employed whereby a laser spot is scanned across an object while capturing, filtering, and digitizing the returned light. Preliminary results of the bacterial auto-fluorescence are reported and plans for future research are discussed. The results to date are encouraging with six of the eight bacterial strains investigated exhibiting auto-fluorescence when excited at 488 nm. Discrimination of these bacterial strains against red meat is shown and techniques for reducing background fluorescence discussed.

  12. REGEN: Ancestral Genome Reconstruction for Bacteria.

    Science.gov (United States)

    Yang, Kuan; Heath, Lenwood S; Setubal, João C

    2012-07-18

    Ancestral genome reconstruction can be understood as a phylogenetic study with more details than a traditional phylogenetic tree reconstruction. We present a new computational system called REGEN for ancestral bacterial genome reconstruction at both the gene and replicon levels. REGEN reconstructs gene content, contiguous gene runs, and replicon structure for each ancestral genome. Along each branch of the phylogenetic tree, REGEN infers evolutionary events, including gene creation and deletion and replicon fission and fusion. The reconstruction can be performed by either a maximum parsimony or a maximum likelihood method. Gene content reconstruction is based on the concept of neighboring gene pairs. REGEN was designed to be used with any set of genomes that are sufficiently related, which will usually be the case for bacteria within the same taxonomic order. We evaluated REGEN using simulated genomes and genomes in the Rhizobiales order.

  13. Degradation of multiwall carbon nanotubes by bacteria

    International Nuclear Information System (INIS)

    Zhang, Liwen; Petersen, Elijah J.; Habteselassie, Mussie Y.; Mao, Liang; Huang, Qingguo

    2013-01-01

    Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading 14 C-labeled MWCNTs into 14 CO 2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia. This result suggests that microbe/MWCNTs interaction may impact the long-term fate of MWCNTs. Highlights: •Mineralization of MWCNTs by a bacterial community was observed. •The mineralization required an external carbon source. •Multiple intermediate products were identified in the MWCNT degrading culture. •Three bacterial species were found likely responsible for MWCNT degradation. -- The 14 C-labeled multiwall carbon nanotubes can be degraded to 14 CO 2 and other byproducts by a bacteria community under natural conditions

  14. Acetic Acid Bacteria as Symbionts of Insects

    KAUST Repository

    Crotti, Elena

    2016-06-14

    Acetic acid bacteria (AAB) are being increasingly described as associating with different insect species that rely on sugar-based diets. AAB have been found in several insect orders, among them Diptera, Hemiptera, and Hymenoptera, including several vectors of plant, animal, and human diseases. AAB have been shown to associate with the epithelia of different organs of the host, they are able to move within the insect’s body and to be transmitted horizontally and vertically. Here, we review the ecology of AAB and examine their relationships with different insect models including mosquitoes, leafhoppers, and honey bees. We also discuss the potential use of AAB in symbiont-based control strategies, such as “Trojan-horse” agents, to block the transmission of vector-borne diseases.

  15. Phosphate Solubilizing Bacteria Adaptive to Vinasse

    Directory of Open Access Journals (Sweden)

    Kahar Muzakhar

    2015-06-01

    Full Text Available Microorganisms identified as phosphate solubilizing bacteria (PSB adaptive to vinasse were successfully screened from sugarcane soil from an agriculatural estate in Jatiroto. By conducting a screening on Pikovskaya’s agar medium (PAM, we found that five different isolates were detected as PSB (pvk-5a, pvk-5b, pvk-6b, pvk-7a, and pvk-8a. Of the five isolates only three could be grown and were found to be adaptive to vinasse based medium without any nutrients added (pvk-5a, pvk-5b and pvk-7a. The three isolates were characterized as coccus and Gram negative with no endospores detected. We suggest that these three isolates can be used as biofertilizer agent to support organic farming.

  16. Enumeration of petroleum hydrocarbon utilizing bacteria

    International Nuclear Information System (INIS)

    Mukherjee, S.; Barot, M.; Levine, A.D.

    1996-01-01

    In-situ biological treatment is one among a number of emerging technologies that may be applied to the remediation of contaminated soils and groundwater. In 1985, a surface spill of 1,500 gallons of dielectric transformer oil at the Sandia National Laboratories (HERMES II facility) resulted in contamination of soil up to depths of 160 feet. The extent of contamination and site characteristics favored the application of in-situ bioremediation as a potential remedial technology. The purpose of this research was to enumerate indigenous microbial populations capable of degrading petroleum hydrocarbons. Microbial enumeration and characterization methods suitably adapted for hydrocarbon utilizing bacteria were used as an indicator of the presence of viable microbial consortia in excavated oil samples with hydrocarbon (TPH) concentrations ranging from 300 to 26,850 ppm. Microbial activity was quantified by direct and streak plating soil samples on silica gel media. Effects of toxicity and temperature were studied using batch cultures of hydrocarbon utilizing bacteria (selectively isolated in an enrichment medium), at temperatures of 20 and 35 C. It was concluded from this study that it is possible to isolate native microorganisms from contaminated soils from depths of 60 to 160 feet, and with oil concentration ranging from 300 to 26,850 ppm. About 62% of the microorganisms isolated form the contaminated soil were capable of using contaminant oil as a substrate for growth and metabolism under aerobic conditions. Growth rates were observed to be 50% higher for the highest contaminant concentration at 20 C. Resistance to toxicity to contaminant oil was also observed to be greater at 20 C than at 35 C

  17. Diversity of rumen bacteria in canadian cervids.

    Directory of Open Access Journals (Sweden)

    Robert J Gruninger

    Full Text Available Interest in the bacteria responsible for the breakdown of lignocellulosic feedstuffs within the rumen has increased due to their potential utility in industrial applications. To date, most studies have focused on bacteria from domesticated ruminants. We have expanded the knowledge of the microbial ecology of ruminants by examining the bacterial populations found in the rumen of non-domesticated ruminants found in Canada. Next-generation sequencing of 16S rDNA was employed to characterize the liquid and solid-associated bacterial communities in the rumen of elk (Cervus canadensis, and white tailed deer (Odocoileus virginianus. Despite variability in the microbial populations between animals, principle component and weighted UniFrac analysis indicated that bacterial communities in the rumen of elk and white tail deer are distinct. Populations clustered according to individual host animal and not the association with liquid or solid phase of the rumen contents. In all instances, Bacteroidetes and Firmicutes were the dominant bacterial phyla, although the relative abundance of these differed among ruminant species and between phases of rumen digesta, respectively. In the elk samples Bacteroidetes were more predominant in the liquid phase whereas Firmicutes was the most prevalent phyla in the solid digesta (P = 1×10(-5. There were also statistically significant differences in the abundance of OTUs classified as Fibrobacteres (P = 5×10(-3 and Spirochaetes (P = 3×10(-4 in the solid digesta of the elk samples. We identified a number of OTUs that were classified as phylotypes not previously observed in the rumen environment. Our results suggest that although the bacterial diversity in wild North American ruminants shows overall similarities to domesticated ruminants, we observed a number of OTUs not previously described. Previous studies primarily focusing on domesticated ruminants do not fully represent the microbial diversity of the

  18. Stress Physiology of Lactic Acid Bacteria

    Science.gov (United States)

    Papadimitriou, Konstantinos; Alegría, Ángel; Bron, Peter A.; de Angelis, Maria; Gobbetti, Marco; Kleerebezem, Michiel; Lemos, José A.; Linares, Daniel M.; Ross, Paul; Stanton, Catherine; Turroni, Francesca; van Sinderen, Douwe; Varmanen, Pekka; Ventura, Marco; Zúñiga, Manuel; Tsakalidou, Effie

    2016-01-01

    SUMMARY Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance. PMID:27466284

  19. Effect of air pollution on the total bacteria and pathogenic bacteria in different sizes of particulate matter.

    Science.gov (United States)

    Liu, Huan; Zhang, Xu; Zhang, Hao; Yao, Xiangwu; Zhou, Meng; Wang, Jiaqi; He, Zhanfei; Zhang, Huihui; Lou, Liping; Mao, Weihua; Zheng, Ping; Hu, Baolan

    2018-02-01

    In recent years, air pollution events have occurred frequently in China during the winter. Most studies have focused on the physical and chemical composition of polluted air. Some studies have examined the bacterial bioaerosols both indoors and outdoors. But few studies have focused on the relationship between air pollution and bacteria, especially pathogenic bacteria. Airborne PM samples with different diameters and different air quality index values were collected in Hangzhou, China from December 2014 to January 2015. High-throughput sequencing of 16S rRNA was used to categorize the airborne bacteria. Based on the NCBI database, the "Human Pathogen Database" was established, which is related to human health. Among all the PM samples, the diversity and concentration of total bacteria were lowest in the moderately or heavily polluted air. However, in the PM2.5 and PM10 samples, the relative abundances of pathogenic bacteria were highest in the heavily and moderately polluted air respectively. Considering the PM samples with different particle sizes, the diversities of total bacteria and the proportion of pathogenic bacteria in the PM10 samples were different from those in the PM2.5 and TSP samples. The composition of PM samples with different sizes range may be responsible for the variances. The relative humidity, carbon monoxide and ozone concentrations were the main factors, which affected the diversity of total bacteria and the proportion of pathogenic bacteria. Among the different environmental samples, the compositions of the total bacteria were very similar in all the airborne PM samples, but different from those in the water, surface soil, and ground dust samples. Which may be attributed to that the long-distance transport of the airflow may influence the composition of the airborne bacteria. This study of the pathogenic bacteria in airborne PM samples can provide a reference for environmental and public health researchers. Copyright © 2017 Elsevier Ltd

  20. Cadmium resistance of endophytic bacteria and rizosféricas bacteria isolated from Oriza sativa in Colombia

    Directory of Open Access Journals (Sweden)

    Nataly Ayubb T

    2017-12-01

    Full Text Available The present study had as objective to evaluate in vitro the resistance of endophytic bacteria and rizospheric bacteria to different concentrations of Cadmium.This bacteria were isolated fron different tissues of commercial rice varieties and from bacteria isolated from the rhizosphere in rice plantations of the Nechí (Antioquía and Achí (Bolivar.  Plant growth promotion was evaluated in vitro by nitrogen fixation, phosphate solubilization and siderophores production of endophytic bacteria. Of each tissue isolated from rice plants was carried out isolation in culture medium for endophytic bacteria, and the soil samples were serially diluted in peptone water. Each sample was determined the population density by counting in CFU / g of tissue and morphotypes were separated by shape, color, size and appearance in culture media. Significant differences were observed for density population of bacteria with respect to tissue, with higher values in root (4x1011 g/root, followed of the stem (3x1010g/etem, leaf (5x109 g/ leaf, flag leaf (3x109 g/ flag leaf and with less density in panicle (4x108 g/panicle. The results of the identification with kit API were confirmed the presence of endophytic bacteria Burkholderia cepaceae and rizospheric bacteria Pseudomona fluorescens With the ability to tolerate different concentrations of Cd, fix nitrogen, solubilize phosphates and produce siderophores.

  1. Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Wilis Ari Setyati

    2017-06-01

    Full Text Available Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36. Pathogenic bacteria Vibrio harveyi was used as positive control. Pathogenic assay was carried out in two different bacterial concentrations, i.e. 10⁸ and 10⁶ cells.mL-1. The results showed that the lowest survival rate (SR of shrimp larvae in positive control V. harveyi was 53 and 65%. Whereas isolates with the highest SR value (100% were obtained from bacteria coded as 13 and 30. Isolates no. 19, 33 and 36 had SR of more than 90%. Total plate count (TPC data showed that the bacteria increased significantly at the end of the study with an average increase value of 24%. The smallest TPC value was shown by bacterial isolate no. 19, while the largest was obtained from the isolate no. 13. These results suggest that all probiotic bacteria were not pathogenic to the vannamei shrimp larvae.   Keywords: aquaculture, shrimp, bioremediation, pathogenesis, vibrio.

  2. Isolation of Crude Oil from Polluted Waters Using Biosurfactants Pseudomonas Bacteria: Assessment of Bacteria Concentration Effects

    Directory of Open Access Journals (Sweden)

    A. Khalifeh

    2013-04-01

    Full Text Available Biological decomposition techniques and isolation of environmental pollutions using biosurfactants bacteria are effective methods of environmental protection. Surfactants are amphiphilic compounds that are produced by local microorganisms and are able to reduce the surface and the stresses between surfaces. As a result, they will increase solubility, biological activity, and environmental decomposition of organic compounds. This study analyzes the effects of biosurfactants on crude oil recovery and its isolation using pseudomonas sea bacteria species. Preparation of biosurfactants was done in glass flasks and laboratory conditions. Experiments were carried out to obtain the best concentration of biosurfactants for isolating oil from water and destroying oil-in-water or water-in-oil emulsions in two pH ranges and four saline solutions of different concentrations. The most effective results were gained when a concentration of 0.1% biosurfactants was applied.

  3. Determination of Ammonia Oxidizing Bacteria and Nitrate Oxidizing Bacteria in Wastewater and Bioreactors

    Science.gov (United States)

    Francis, Somilez Asya

    2014-01-01

    The process of water purification has many different physical, chemical, and biological processes. One part of the biological process is the task of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). Both play critical roles in the treatment of wastewater by oxidizing toxic compounds. The broad term is nitrification, a naturally occurring process that is carried out by AOB and NOB by using oxidation to convert ammonia to nitrite and nitrite to nitrate. To monitor this biological activity, bacterial staining was performed on wastewater contained in inoculum tanks and biofilm samples from bioreactors. Using microscopy and qPCR, the purpose of this experiment was to determine if the population of AOB and NOB in wastewater and membrane bioreactors changed depending on temperature and hibernation conditions to determine the optimal parameters for AOB/NOB culture to effectively clean wastewater.

  4. Bacteria, some permanent tenants Space Station; Bacteria, unos inquilinos permanentes de la estacion espacial

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, B.

    2015-07-01

    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 {sup c}leanroom '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)

  5. Seed-vectored endophytic bacteria modulate development of rice seedlings.

    Science.gov (United States)

    Verma, S K; Kingsley, K; Irizarry, I; Bergen, M; Kharwar, R N; White, J F

    2017-06-01

    The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development. © 2017 The Society for Applied Microbiology.

  6. BioNLP Shared Task--The Bacteria Track.

    Science.gov (United States)

    Bossy, Robert; Jourde, Julien; Manine, Alain-Pierre; Veber, Philippe; Alphonse, Erick; van de Guchte, Maarten; Bessières, Philippe; Nédellec, Claire

    2012-06-26

    We present the BioNLP 2011 Shared Task Bacteria Track, the first Information Extraction challenge entirely dedicated to bacteria. It includes three tasks that cover different levels of biological knowledge. The Bacteria Gene Renaming supporting task is aimed at extracting gene renaming and gene name synonymy in PubMed abstracts. The Bacteria Gene Interaction is a gene/protein interaction extraction task from individual sentences. The interactions have been categorized into ten different sub-types, thus giving a detailed account of genetic regulations at the molecular level. Finally, the Bacteria Biotopes task focuses on the localization and environment of bacteria mentioned in textbook articles. We describe the process of creation for the three corpora, including document acquisition and manual annotation, as well as the metrics used to evaluate the participants' submissions. Three teams submitted to the Bacteria Gene Renaming task; the best team achieved an F-score of 87%. For the Bacteria Gene Interaction task, the only participant's score had reached a global F-score of 77%, although the system efficiency varies significantly from one sub-type to another. Three teams submitted to the Bacteria Biotopes task with very different approaches; the best team achieved an F-score of 45%. However, the detailed study of the participating systems efficiency reveals the strengths and weaknesses of each participating system. The three tasks of the Bacteria Track offer participants a chance to address a wide range of issues in Information Extraction, including entity recognition, semantic typing and coreference resolution. We found common trends in the most efficient systems: the systematic use of syntactic dependencies and machine learning. Nevertheless, the originality of the Bacteria Biotopes task encouraged the use of interesting novel methods and techniques, such as term compositionality, scopes wider than the sentence.

  7. Acetic acid bacteria: A group of bacteria with versatile biotechnological applications.

    Science.gov (United States)

    Saichana, Natsaran; Matsushita, Kazunobu; Adachi, Osao; Frébort, Ivo; Frebortova, Jitka

    2015-11-01

    Acetic acid bacteria are gram-negative obligate aerobic bacteria assigned to the family Acetobacteraceae of Alphaproteobacteria. They are members of the genera Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia, Granulibacter, Tanticharoenia, Ameyamaea, Neokomagataea, and Komagataeibacter. Many strains of Acetobacter and Komagataeibacter have been known to possess high acetic acid fermentation ability as well as the acetic acid and ethanol resistance, which are considered to be useful features for industrial production of acetic acid and vinegar, the commercial product. On the other hand, Gluconobacter strains have the ability to perform oxidative fermentation of various sugars, sugar alcohols, and sugar acids leading to the formation of several valuable products. Thermotolerant strains of acetic acid bacteria were isolated in order to serve as the new strains of choice for industrial fermentations, in which the cooling costs for maintaining optimum growth and production temperature in the fermentation vessels could be significantly reduced. Genetic modifications by adaptation and genetic engineering were also applied to improve their properties, such as productivity and heat resistance. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Detection of Sulphate-Reducing Bacteria and Others Cultivable Facultative Bacteria in Dental Tissues

    Directory of Open Access Journals (Sweden)

    Lúcio de Souza Gonçalves

    2014-01-01

    Full Text Available Aim: To detect for the presence of sulphate-reducing bacteria (SRB and evaluate the possible association between SRB and cultivable facultative bacterial of oral sites with different periodontal conditions. Methods: The study was carried out on 9 samples from different oral sites in 8 patients (two samples were collected from the same patient. Material was collected using modified Postgate E culture medium, indicated for the growth and isolation of SRB. In addition, a reducing solution for anaerobic bacteria was used as a transport solution for facultative bacteria and identified by polymerase chain reaction amplification (PCR and sequencing of the 16S rRNA gene. Results: SRB was found in 3 patient samples: the first in a root fragment, the second in a root fragment and a healthy tooth with vertical bone loss and a mobility degree of 3; and the third in a healthy tooth extracted for orthodontic treatment. In the final patient, the cultivable facultative species Lactobacillus casei was identified. Other facultative bacterial species were identified in patient 5 (Kurthia Gibsonii and patient 7 (Pseudomonas aeruginosa. Conclusions: The detection of SRB in different dental tissues with distinct periodontal features demonstrated that new studies need to be developed in order to determine the true role of SRB in the oral microbiota. In addition, it was possible to verify the presence of Lactobacillus casei together with SRB in one sample.

  9. Mechanistic modeling of biocorrosion caused by biofilms of sulfate reducing bacteria and acid producing bacteria.

    Science.gov (United States)

    Xu, Dake; Li, Yingchao; Gu, Tingyue

    2016-08-01

    Biocorrosion is also known as microbiologically influenced corrosion (MIC). Most anaerobic MIC cases can be classified into two major types. Type I MIC involves non-oxygen oxidants such as sulfate and nitrate that require biocatalysis for their reduction in the cytoplasm of microbes such as sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). This means that the extracellular electrons from the oxidation of metal such as iron must be transported across cell walls into the cytoplasm. Type II MIC involves oxidants such as protons that are secreted by microbes such as acid producing bacteria (APB). The biofilms in this case supply the locally high concentrations of oxidants that are corrosive without biocatalysis. This work describes a mechanistic model that is based on the biocatalytic cathodic sulfate reduction (BCSR) theory. The model utilizes charge transfer and mass transfer concepts to describe the SRB biocorrosion process. The model also includes a mechanism to describe APB attack based on the local acidic pH at a pit bottom. A pitting prediction software package has been created based on the mechanisms. It predicts long-term pitting rates and worst-case scenarios after calibration using SRB short-term pit depth data. Various parameters can be investigated through computer simulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Laminar flow assisted anisotropic bacteria absorption for chemotaxis delivery of bacteria-attached microparticle

    Science.gov (United States)

    Huh, Keon; Oh, Darong; Son, Seok Young; Yoo, Hyung Jung; Song, Byeonghwa; Cho, Dong-il Dan; Seo, Jong-Mo; Kim, Sung Jae

    2016-12-01

    The concepts of microrobots has been drawn significant attentions recently since its unprecedented applicability in nanotechnology and biomedical field. Bacteria attached microparticles presented in this work are one of pioneering microrobot technology for self-propulsion or producing kinetic energy from ambient for their motions. Microfluidic device, especially utilizing laminar flow characteristics, were employed for anisotropic attachment of Salmonella typhimurium flagellated chemotactic bacteria to 30 um × 30 um and 50 um × 50 um microparticles that made of biodegradable polymer. Any toxic chemicals or harmful treatments were excluded during the attachment process and it finished within 100 s for the anisotropic attachment. The attachments were directly confirmed by fluorescent intensity changes and SEM visualization. Chemotaxis motions were tracked using aspartate and the maximum velocity of the bacteria-attached microrobot was measured to be 5 um/s which is comparable to prior state of art technologies. This reusable and scalable method could play a key role in chemotaxis delivery of functional microparticles such as drug delivery system.

  11. Bioactive proteins against pathogenic and spoilage bacteria

    Directory of Open Access Journals (Sweden)

    Mahmoud Z. Sitohy

    2014-10-01

    Full Text Available Background: It is likely that both human nutrition and the nutrition of livestock are benefited by the presence of bioactive proteins within their respective diet regimes. Bioactive proteins have been defined as specific protein fragments that positively impact bodily functions or conditions and may, ultimately, influence overall human health. The ingestion of bioactive proteins may have an effect on the major body systems—namely, the cardiovascular, digestive, immune and nervous systems. According to their functional properties, bioactive proteins may be classified as antimicrobial, antithrombotic, antihypertensive, opioid, immune-modulatory, mineral binding and anti-oxidative. There are many examples of biologically active food proteins and active peptides that can be obtained from various food protein sources. They have a physiological significance beyond the pure nutritional requirements; in other wordsthey have the acquisition of nitrogen for normal growth and maintenance. Objective: This study aims to specify and characterize the extent and mode of action of bioactive proteins in their native form, (glycinin, glycinin basic sub-unit and β-conglycinin against specific main pathogens (Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica serovar Enteritidis. We will be using standard media while identifying the main constituents responsible for this action. Methods: Glycinin, basic sub-unit and β-conglycinin were isolated from soybean protein and tested for their antimicrobial action against pathogenic and spoilage bacteria, They were thencompared to the properties of penicillin. Methylated soybean protein and also methylated chickpea protein (MSP and MCP, with isoelectric points around pI 8, were prepared by esterifying. 83 % of their free carboxyl groups and their interactions with Gram positive and Gram negative bacteria were examined. Results: The three divisions of cationic proteins exhibited antibacterial

  12. Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Bryant, Donald A

    2004-01-01

    Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria...... (Chlorobi) and the filamentous anoxygenic phototrophic bacteria ("Chloroflexales"), are otherwise quite different, both physiologically and phylogenetically. This review summarizes how genome sequence information facilitated studies of the biosynthesis and function of the photosynthetic apparatus...... a and carotenoid biosynthesis enzymes, gene cluster analysis in Cfx. aurantiacus, and gene inactivation studies in Chl. tepidum. Based on these results, BChl a and BChl c biosynthesis is similar in the two organisms, whereas carotenoid biosynthesis differs significantly. In agreement with its facultative anaerobic...

  13. Biochanin A improves fiber fermentation by cellulolytic bacteria

    Science.gov (United States)

    The objective was to determine the effect of the isoflavone biochanin A (BCA) on rumen cellulolytic bacteria and consequent fermentative activity. When bovine microbial rumen cell suspensions (n = 3) were incubated (24 h, 39 °C) with ground hay, cellulolytic bacteria proliferated, short chain fatty...

  14. Nitrogen acquisition in Agave tequilana from degradation of endophytic bacteria.

    Science.gov (United States)

    Beltran-Garcia, Miguel J; White, James F; Prado, Fernanda M; Prieto, Katia R; Yamaguchi, Lydia F; Torres, Monica S; Kato, Massuo J; Medeiros, Marisa H G; Di Mascio, Paolo

    2014-11-06

    Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from (15)N-labeled bacteria to plants. Bacillus tequilensis cells grown in a minimal medium with (15)NH4Cl as the nitrogen source were watered onto plants growing in sand. We traced incorporation of (15)N into tryptophan, deoxynucleosides and pheophytin derived from chlorophyll a. Probes for hydrogen peroxide show its presence during degradation of bacteria in plant tissues, supporting involvement of reactive oxygen in the degradation process. In another experiment to assess nitrogen absorbed as a result of endophytic colonization of plants we demonstrated that endophytic bacteria potentially transfer more nitrogen to plants and stimulate greater biomass in plants than heat-killed bacteria that do not colonize plants but instead degrade in the soil. Findings presented here support the hypothesis that some plants under nutrient limitation may degrade and obtain nitrogen from endophytic microbes.

  15. Fecal bacteria source characterization and sensitivity analysis of SWAT 2005

    Science.gov (United States)

    The Soil and Water Assessment Tool (SWAT) version 2005 includes a microbial sub-model to simulate fecal bacteria transport at the watershed scale. The objectives of this study were to demonstrate methods to characterize fecal coliform bacteria (FCB) source loads and to assess the model sensitivity t...

  16. Lactic Acid Bacteria : embarking on 30 more years of research

    NARCIS (Netherlands)

    Kok, Jan; Johansen, Eric; Kleerebezem, Michiel; Teusink, Bas

    2014-01-01

    The 11th International Symposium on Lactic Acid Bacteria Lactic Acid Bacteria play important roles in the pro- duction of food and feed and are increasingly used as health-promoting probiotics. The incessant scientific interest in these microorganisms by academic research groups as well as by

  17. Lactic Acid Bacteria Differentially Activate Natural Killer Cells

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen; Christensen, Hanne Risager; Frøkiær, Hanne

    antigen presenting cells and T-cells. Bacteria translocating across the gastrointestinal mucosa are presumed to gain access to NK cell compartments, as consumption of certain strains of lactic acid bacteria has been shown to increase in vivo NK cytotoxic activity. On-going research in our lab aims...

  18. Population dynamics of bacteria introduced into bentonite amended soil

    NARCIS (Netherlands)

    Heijnen, C.

    1992-01-01

    Bacteria have frequently been introduced into the soil environment, e.g. for increasing crop production or for biological control purposes. Many applications require high numbers of surviving organisms in order to be effective. However, survival of bacteria after introduction into soil is

  19. Antimicrobial resistance in aerobic bacteria isolated from oral ...

    African Journals Online (AJOL)

    ... varied antimicrobial susceptibility patterns. The oral cavities of hunting dogs are laden with multi-drug resistant bacteria of significant public health importance that could be transferred to humans through contaminated hunted games and bite wound. Keywords: Aerobic bacteria, Antimicrobial resistance, Dogs, Oral cavity, ...

  20. Glass bead transformation method for gram-positive bacteria

    OpenAIRE

    Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

    2009-01-01

    A simple, inexpensive and reproducible transformation method was developed for Gram-positive bacteria. It was based on agitation of bacterial protoplasts with glass beads in the presence of DNA and polyethylene glycol. By using this method, introduction of pGK12 into protoplasts of several strains of Gram-positive bacteria was achieved.

  1. Sulphur oxidising bacteria in mangrove ecosystem: A review ...

    African Journals Online (AJOL)

    Sulphur-oxidizing bacteria such as photoautotrophs, chemolithotrophs and heterotrophs play an important role in the mangrove environment for the oxidation of the toxic sulphide produced by sulphur reducing bacteria and act as a key driving force behind all sulphur transformations in the mangrove ecosystem which is ...

  2. Heme and menaquinone induced electron transport in lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.; Smit, B.; Santos, dos F.; Riel, van J.; Vos, de W.M.; Hugenholtz, J.

    2009-01-01

    ABSTRACT: BACKGROUND: For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait.

  3. The identification of anaerobic bacteria using MALDI-TOF MS

    NARCIS (Netherlands)

    Veloo, A. C. M.; Welling, G. W.; Degener, J. E.

    Matrix Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has gained more and more popularity for the identification of bacteria. Several studies show that bacterial diagnosticis is being revolutionized by the application of MALDI-TOF MS. For anaerobic bacteria,

  4. Hydrocarbon degradation potentials of bacteria isolated from spent ...

    African Journals Online (AJOL)

    Hydrocarbon degradation potentials of bacteria isolated from spent lubricating oil contaminated soil. ... This study has shown that resident bacteria strains in lubricating oil contaminated soils have potential application in the bioremediation of oil polluted sites and enhance the possibility of developing models and strategies ...

  5. Hydrocarbon-degrading Capability of Bacteria isolated from a Maize ...

    African Journals Online (AJOL)

    Hydrocarbon-degrading Capability of Bacteria isolated from a Maize-Planted, Kerosene-contaminated Ilorin Alfisol. ... also revealed that some bacteria survive and even thrive in kerosene contaminated soil and hence have the potential to be used in biodegradation and/or bioremediation of oil contaminated soils and water.

  6. Rapid separation of bacteria from blood - Chemical aspects.

    Science.gov (United States)

    Alizadeh, Mahsa; Wood, Ryan L; Buchanan, Clara M; Bledsoe, Colin G; Wood, Madison E; McClellan, Daniel S; Blanco, Rae; Ravsten, Tanner V; Husseini, Ghaleb A; Hickey, Caroline L; Robison, Richard A; Pitt, William G

    2017-06-01

    To rapidly diagnose infectious organisms causing blood sepsis, bacteria must be rapidly separated from blood, a very difficult process considering that concentrations of bacteria are many orders of magnitude lower than concentrations of blood cells. We have successfully separated bacteria from red and white blood cells using a sedimentation process in which the separation is driven by differences in density and size. Seven mL of whole human blood spiked with bacteria is placed in a 12-cm hollow disk and spun at 3000rpm for 1min. The red and white cells sediment more than 30-fold faster than bacteria, leaving much of the bacteria in the plasma. When the disk is slowly decelerated, the plasma flows to a collection site and the red and white cells are trapped in the disk. Analysis of the recovered plasma shows that about 36% of the bacteria is recovered in the plasma. The plasma is not perfectly clear of red blood cells, but about 94% have been removed. This paper describes the effects of various chemical aspects of this process, including the influence of anticoagulant chemistry on the separation efficiency and the use of wetting agents and platelet aggregators that may influence the bacterial recovery. In a clinical scenario, the recovered bacteria can be subsequently analyzed to determine their species and resistance to various antibiotics. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. unanswerable questions just as interesting as unculturable bacteria!

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. UNANSWERABLE QUESTIONS JUST AS INTERESTING AS UNCULTURABLE BACTERIA! How can landmark research be done in a college? What is the need to isolate novel bacteria when the ones already isolated are not completely studied? How can one do ...

  8. Bacteria isolated from the airways of paediatric patients with ...

    African Journals Online (AJOL)

    Knowledge of which bacteria are found in the airways of paediatric patients with bronchiectasis unrelated to cystic fibrosis. (CF) is important in defining empirical antibiotic guidelines for the treatment of acute infective exacerbations. Objective. To describe the bacteria isolated from the airways of children with non-CF ...

  9. Effect of inulin and probiotic bacteria on growth, survival, immune ...

    African Journals Online (AJOL)

    The effect of inulin and probiotic bacteria on the growth, survival, immune response and viral prevalence of white spot syndrome virus (WSSV) in white shrimp was evaluated. Presumptive bacilli and lactic acid bacteria (LAB) were characterized for hemolytic and enzymatic activity, hydrophobicity and antagonism against ...

  10. Isolation and characterization of heavy metal tolerant bacteria from ...

    African Journals Online (AJOL)

    Panteka stream is a flowing stream polluted with wastes from the activities of mechanics. Water samples collected at different points of the stream were analysed in order to determine the level of heavy metal contamination and bacteria diversity with the view to elucidating the bioremediating potentials of the bacteria isolates ...

  11. 9th International Symposium on Lactic Acid Bacteria

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Poolman, Berend; Hugenholtz, Jeroen

    What’s new in the field of lactic acid bacteria? The 9th International Symposium on Lactic Acid Bacteria (LAB9) will take place 31 August to 4 September 2008 in Egmond aan Zee, The Netherlands. Traditionally, the triannual LAB symposium focuses on the themes of genetics, physiology, and applications

  12. Unusual rise in mercury-resistant bacteria in coastal environs

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; De, J.

    A sharp rise in mercury-resistant bacteria (MRB) capable of tolerating very high concentration of Hg was observed over the last 3-4 years in the coastal environs of India. While none or negligible colony-forming units (CFU) of bacteria were counted...

  13. Screening of endophytic plant growth-promoting bacteria isolated ...

    African Journals Online (AJOL)

    Probiotic bacteria, inhabiting the endosphere of plants, presents a major opportunity to develop cheap and eco-friendly alternatives to synthetic agrochemicals. Using standard microbiological procedures, culturable bacteria were isolated from the endosphere (root, stem and leaf) of two Nigerian rice varieties (Ofada and ITA ...

  14. Stalking Antibiotic-Resistant Bacteria in Common Vegetables

    Science.gov (United States)

    Brock, David; Boeke, Caroline; Josowitz, Rebecca; Loya, Katherine

    2004-01-01

    The study developed a simple experimental protocol for studying antibiotic resistant bacteria that will allow students to determine the proportion of such bacteria found on common fruit and vegetable crops. This protocol can open up the world of environmental science and show how human behavior can dramatically alter ecosystems.

  15. Effects of supplementing lactic acid bacteria on fecal microbiota ...

    African Journals Online (AJOL)

    Results: The results indicated that Lactobacillus plantarum strain L.p X3-2B increased fecal lactic acid bacteria(LAB) and Bifidobacterium while resisting the growth of harmful bacteria. Viable counts of LAB and Bifidobacterium reached 8 log cfu/mL after feeding for 14 days. Fecal pH in the control group was high in ...

  16. Compatible solutes in lactic acid bacteria subjected to water stress

    NARCIS (Netherlands)

    Kets, E.P.W.

    1997-01-01

    The goal of the research project described in this thesis was to investigate the protective effect of compatible solutes on tactic acid bacteria subjected to drying. Dried preparations of lactic acid bacteria are applied as starter cultures in feed and food industries. Dried starter

  17. The Shared Antibiotic Resistome of Soil Bacteria and Human Pathogens

    DEFF Research Database (Denmark)

    Forsberg, Kevin J.; Reyes, Alejandro; Wang, Bin

    2012-01-01

    protocol to assemble short-read sequence data after antibiotic selection experiments, using 12 different drugs in all antibiotic classes, and compared antibiotic resistance gene sequences between soil bacteria and clinically occurring pathogens. Sixteen sequences, representing seven gene products, were...... discovered in farmland soil bacteria within long stretches of perfect nucleotide identity with pathogenic proteobacteria....

  18. Flow cytometric assessment of viability of lactic acid bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.; Bloemen, K.; Breeuwer, P.; Rombouts, F.M.; Abee, T.

    2001-01-01

    The viability of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. We investigated the usefulness of flow cytometry (FCM) for viability assessment of lactic acid bacteria. The esterase substrate carboxyfluorescein diacetate (cFDA) and the dye exclusion DNA

  19. Performance of shcc with bacteria for concrete patch repair

    NARCIS (Netherlands)

    Sierra Beltran, M.G.; Jonkers, H.M.; Schlangen, E.

    2014-01-01

    The overall performance of concrete patch repair systems depends on the durability of and compatibility between the concrete substrate and the repair material. This paper investigates the performance of a new type of SHCC material with embedded bacteria as a repair material. The bacteria are a

  20. CcpA-dependent carbon catabolite repression in bacteria

    NARCIS (Netherlands)

    Warner, JB; Lolkema, JS; Warner, Jessica B.

    2003-01-01

    Carbon catabolite repression (CCR) by transcriptional regulators follows different mechanisms in gram-positive and gram-negative bacteria. In gram-positive bacteria, CcpA-dependent CCR is mediated by phosphorylation of the phosphoenolpyruvate:sugar phosphotransferase system intermediate HPr at a

  1. Visualizing aquatic bacteria by light and transmission electron microscopy.

    Science.gov (United States)

    Silva, Thiago P; Noyma, Natália P; Duque, Thabata L A; Gamalier, Juliana P; Vidal, Luciana O; Lobão, Lúcia M; Chiarini-Garcia, Hélio; Roland, Fábio; Melo, Rossana C N

    2014-01-01

    The understanding of the functional role of aquatic bacteria in microbial food webs is largely dependent on methods applied to the direct visualization and enumeration of these organisms. While the ultrastructure of aquatic bacteria is still poorly known, routine observation of aquatic bacteria by light microscopy requires staining with fluorochromes, followed by filtration and direct counting on filter surfaces. Here, we used a new strategy to visualize and enumerate aquatic bacteria by light microscopy. By spinning water samples from varied tropical ecosystems in a cytocentrifuge, we found that bacteria firmly adhere to regular slides, can be stained by fluorochoromes with no background formation and fast enumerated. Significant correlations were found between the cytocentrifugation and filter-based methods. Moreover, preparations through cytocentrifugation were more adequate for bacterial viability evaluation than filter-based preparations. Transmission electron microscopic analyses revealed a morphological diversity of bacteria with different internal and external structures, such as large variation in the cell envelope and capsule thickness, and presence or not of thylakoid membranes. Our results demonstrate that aquatic bacteria represent an ultrastructurally diverse population and open avenues for easy handling/quantification and better visualization of bacteria by light microscopy without the need of filter membranes.

  2. Transmission of nephridial bacteria of the earthworm Eisenia fetida.

    Science.gov (United States)

    Davidson, Seana K; Stahl, David A

    2006-01-01

    The lumbricid earthworms (annelid family Lumbricidae) harbor gram-negative bacteria in their excretory organs, the nephridia. Comparative 16S rRNA gene sequencing of bacteria associated with the nephridia of several earthworm species has shown that each species of worm harbors a distinct bacterial species and that the bacteria from different species form a monophyletic cluster within the genus Acidovorax, suggesting that there is a specific association resulting from radiation from a common bacterial ancestor. Previous microscopy and culture studies revealed the presence of bacteria within the egg capsules and on the surface of embryos but did not demonstrate that the bacteria within the egg capsule were the same bacteria that colonized the nephridia. We present evidence, based on curing experiments, in situ hybridizations with Acidovorax-specific probes, and 16S rRNA gene sequence analysis, that the egg capsules contain high numbers of the bacterial symbiont and that juveniles are colonized during development within the egg capsule. Studies exposing aposymbiotic hatchlings to colonized adults and their bedding material suggested that juvenile earthworms do not readily acquire bacteria from the soil after hatching but must be colonized during development by bacteria deposited in the egg capsule. Whether this is due to the developmental stage of the host or the physiological state of the symbiont remains to be investigated.

  3. Response of resident bacteria in a tropical detergent effluent ...

    African Journals Online (AJOL)

    Bacteria were isolated from a tropical detergent-polluted stream, and their responses to linear alkylbenzene sulfonate (LAS) were investigated. The responses of the resident bacteria were assessed in terms of their ability or failure to grow in the presence of LAS and of their potential to degrade the surfactant. Eighteen ...

  4. Anti-fungal properties of chitinolytic dune soil bacteria

    NARCIS (Netherlands)

    De Boer, W.; Klein Gunnewiek, P.J.A.; Lafeber, P.; Janse, J.H.; Spit, B.E.; Woldendorp, J.W.

    1998-01-01

    Anti-fungal properties of chitinolytic soil bacteria may enable them to compete successfully for chitin with fungi. Additionally, the production of chitinase may be part of a lytic system that enables the bacteria to use living hyphae rather than chitin as the actual growth substrate, since chitin

  5. Gram-positive bacteria persisting in the food production environment

    DEFF Research Database (Denmark)

    Knøchel, Susanne; Harmsen, Morten; Knudsen, Bettina

    2008-01-01

    Many gram-positive bacteria are able to form aggregates or biofilms and resist external stress factors and some gram-positive pathogenic bacteria such as Listeria monocytogenes and Bacillus cereus may persist in the food production environment for extended periods. Most research has focussed...

  6. Prevalence and drug resistance in bacteria of the urinary tract ...

    African Journals Online (AJOL)

    Objective: To obtain data on the prevalence of antibiotic resistance in bacteria isolated from patients with suspected urinary tract infection in Bulawayo province, Zimbabwe. Method: Over a period of one year, 257 urine samples were analyzed for bacteria by standard procedures. Antimicrobial susceptibility testing of isolated ...

  7. Use of thermophilic bacteria for bioremediation of petroleum contaminants

    International Nuclear Information System (INIS)

    Al-Maghrabi, I.M.A.; Bin Aqil, A.O.; Chaalal, O.; Islam, M.R.

    1999-01-01

    Several strains of thermophilic bacteria were isolated from the environment of the United Arab Emirates. These bacteria show extraordinary resistance to heat and have their maximum growth rate around 60--80 C. This article investigates the potential of using these facultative bacteria for both in situ and ex situ bioremediation of petroleum contaminants. In a series of batch experiments, bacterial growth was observed using a computer image analyzer following a recently developed technique. These experiments showed clearly that the growth rate is enhanced in the presence of crude oil. This is coupled with a rapid degradation of the crude oil. These bacteria were found to be ideal for breaking down long-chain organic molecules at a temperature of 40 C, which is the typical ambient temperature of the Persian Gulf region. The same strains of bacteria are also capable of surviving in the presence of the saline environment that can prevail in both sea water and reservoir connate water. This observation prompted further investigation into the applicability of the bacteria in microbial enhanced oil recovery. In the United Arab Emirates, the reservoirs are typically at a temperature of around 85 C. Finally, the performance of the bacteria is tested in a newly developed bioreactor that uses continuous aeration through a transverse slotted pipe. This reactor also uses mixing without damaging the filamentous bacteria. In this process, the mechanisms of bioremediation are identified

  8. Removal of crude petroleum hydrocarbons by heterotrophic bacteria ...

    African Journals Online (AJOL)

    Nitrogenous fertilizer (NPK) plant effluents from NAFCON were used in amending plots of land experimentally polluted with crude oil. Counts of heterotrophic bacteria (THBC) and fungi (TF), and of petroleum utilizing bacteria (PUB) and fungi (PUF) were monitored during an 8 weeks period. Counts obtained showed that ...

  9. Bacteriocins and lactic acid bacteria - a minireview | Savadogo ...

    African Journals Online (AJOL)

    Fermentation of various foods by lactic acid bacteria (LAB) is one of the oldest forms of biopreservation practised by mankind. Bacterial antagonism has been recognized for over a century but in recent years this phenomenon has received more scientific attention, particulary in the use of various strains of lactic acid bacteria.

  10. Selection of local extremophile lactic acid bacteria with high capacity ...

    African Journals Online (AJOL)

    This study is related to the isolation and identification of strains of local thermophilic lactic acid bacteria belonging to the species, Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria can exist under extreme conditions of the digestive tract (acidity and high concentration of bile salts) and have a high ...

  11. The bacteria profiles of wounds in diabetic patients hospitalized in ...

    African Journals Online (AJOL)

    Diabetic wound infections still remain a health concern such that correct identification of bacteria is essential in monitoring the spread of the infections as well as in the administration of the correct treatment. This study therefore focuses on isolating and identifying bacteria present in diabetic wounds of hospitalized patients in ...

  12. Antibacterial Activities of Lactic Acid Bacteria Isolated from Selected ...

    African Journals Online (AJOL)

    Members of lactic acid bacteria (LAB) are known probiotics and have been reported to have antimicrobial properties. Although various researchers have documented the isolation of these bacteria from fruits and vegetables, studies on LAB associated with lettuce, cucumber and cabbage are limited and non-existing in ...

  13. Screening and identification of lactic acid bacteria isolated from ...

    African Journals Online (AJOL)

    The lactic acid bacteria (LAB) isolated from sorghum (Sorghum bicolor. L.) silage were identified during different periods of evolution of sorghum silage in west Algeria. Morphological, physiological, biochemical and technological techniques were used to characterize lactic acid bacteria isolates. A total number of 27 ...

  14. Damage mechanisms of pathogenic bacteria in drinking water ...

    African Journals Online (AJOL)

    This study aimed at elucidating the inactivation mechanisms of pathogenic bacteria in drinking water during chlorine and solar disinfection using a simple plating method. The well-known bacterial model Escherichia coli was used as pathogenic bacteria for the experiments. The damage mechanisms of E. coli were ...

  15. Utilization of Cypermethrin by bacteria isolated from irrigated soils ...

    African Journals Online (AJOL)

    Soil bacteria capable of utilizing Cypermethrin as a source of carbon were isolated using enrichment technique. The bacteria were Psuedomonas aeruginosa, Serratia spp Micrococcus sp, Staphylococci and Streptococcus sp. Growth of P. aeruginosa was determined in the presence of 1:106 and 1:105 Cypermethrin in ...

  16. The Effect of Antioxidants on Antibiotic Sensitivity of Bacteria

    OpenAIRE

    Azade ATTAR; Akif İ. QURBANOV

    2007-01-01

    Objective: The effect of different concentrations of antioxidants (ascorbic acid, emoxipin, tocopherol acetate and ionol) on antibiotic sensitivity of bacteria was studied. Method: Bacteria belong to different respiration types: Pseudomonas aeruginosa as aerobe and Escherichia coli as facultative anaerobe were used. Antibiotic sensitivity of microorganisms was determined as minimum inhibitory concentration (MIC) by dilution test. Results: Different concentrations of antioxidants increased the...

  17. 'Atypical' bacteria are a common cause of community-acquired ...

    African Journals Online (AJOL)

    Objectives. To assess the proportion of cases of community· acquired pneumonia caused by 'atypical' bacteria, inclUding the recently discovered Chlamydia pneumoniae, and to compare the clinical, radiographic and laboratory features of patients with and without 'atypical' bacteria. Methods. A prospective serological ...

  18. Degradation of riverine dissolved organic matter by seawater bacteria

    NARCIS (Netherlands)

    Rochelle-Newall, E.J.; Pizay, M-D.; Middelburg, J.J.; Boschker, H.T.S.; Gattuso, J.P.

    2004-01-01

    The functional response of a seawater bacterial community transplanted into freshwater dissolved organic matter (DOM) was investigated together with the response of natural populations of bacteria to size-fractioned natural source water. Seawater bacteria were incubated over a period of 8 d in

  19. Pathogen detection and gut bacteria identification in Apis cerana ...

    African Journals Online (AJOL)

    acer

    other lactic acid bacteria, were isolated from larvae and adult workers, but gave conflicting preliminary identities based on their biochemistry-morphology versus sequence analysis of a partial fragment (1.4 kb) of their 16S rRNA. Key words: Apis cerana indica, bee pathogens, gut bacteria, multiplex polymerase chain ...

  20. Antimicrobial properties of probiotic bacteria from various sources

    African Journals Online (AJOL)

    OKEREKE HOPE C

    2012-05-15

    May 15, 2012 ... The lactic acid bacteria (LAB), a component of several fermented foods including ... lactic acid bacteria grown in MRS broth for 20 to 24 h using centrifugation .... vacuum packed chill-stored meat has potential application for ...

  1. Simple and convenient method for culturing anaerobic bacteria.

    OpenAIRE

    Behbehani, M J; Jordan, H V; Santoro, D L

    1982-01-01

    A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.

  2. The Bacteria Quality Of The Indigenously Fermented Milk Product ...

    African Journals Online (AJOL)

    Fifty samples of 'nono', a fermented milk product akin to yoghurt, were carefully collected from three markets in Maiduguri municipality, and were examined for the presence of pathogenic bacteria. Twenty-eight percent of the samples were found to be contaminated with aciduric pathogenic bacteria that may cause ...

  3. The bacteriological safety and antimicrobial susceptibility of bacteria ...

    African Journals Online (AJOL)

    In developing countries the major sources of food-borne illnesses are street vended foods. The aim of this study was thus to assess the prevalence and antibiogram of bacteria from white lupin in Bahir Dar Town. METHODS: A total of 40 samples were processed for detection of indicator bacteria and pathogens from ...

  4. Energy sources of yoghurt bacteria and enhancement of their ...

    African Journals Online (AJOL)

    The energy sources of yoghurt bacteria (Streptococcus thermophilus and Lactobacillus bulgaricus) were examined with a focus on probable impact of sucrose on their galactose uptake. Yoghurt bacteria were isolated from samples of yoghurt which were purchased from different outlets and kept under refrigeration ...

  5. [Bacteriophages in the battle against multidrug resistant bacteria

    NARCIS (Netherlands)

    Meer, J.W.M. van der; Vandenbroucke-Grauls, C.

    2018-01-01

    Bacteriophages are viruses that infect bacteria. They are highly specific for a bacterial species. The so-called 'lytic phages' can lyse bacteria when they infect them; these phages can be used to treat bacterial infections. Despite a century of experience with phage therapy, the evidence for

  6. Mutagenesis of metal compounds in bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, H

    1974-01-01

    The mutagenic activity of 41 metal compounds was examined by applying the Rec-assay method with Bacillus subtilis H17 (rec/sup +/) and M45 (rec/sup -/) strains. Among these compounds, Na/sub 2/HAsO/sub 4/, CdCl/sub 2/, K/sub 2/CrO/sub 4/, K/sub 2/Cr/sub 2/O/sub 7/, CH/sub 3/HgCl, C/sub 2/H/sub 5/HgCl, CH/sub 3/COOHgC/sub 6/H/sub 5/, MnCl/sub 2/, MnNO/sub 3/, MnSO/sub 4/, Mn(CH/sub 3/COO)/sub 2/, (NH/sub 4/)/sub 2/MoO/sub 4/ and KMoO/sub 4/ showed positive results. The reactions of K/sub 2/Cr/sub 2/O/sub 7/ and (NH/sub 4/)/sub 2/MoO/sub 4/ were especially strong in the assay. Therefore, mutation induction to reversion (try/sup +/) and streptomycin resistance (SM/sup r/) of E. coli B/r WP2 try/sup -/ (hcl/sup +/ and hcr/sup -/) by the two compounds were examined by the following two experimental procedures. Stationary phase bacteria were exposed to the compounds at high concentrations (6.9 x 10/sup -3/ approx. 3.44 x 10/sup -2/M) in M9 buffer for 15 min at 37/sup -/ with shaking. After incubation at 37/sup 0/ for 48 h visible colonies on the plates were scored. Bacteria in M9 buffer were plated in media supplemented with low concentrations (1.7 x 10/sup -5/ approx. 3.4 x 10/sup -5/M) of the compounds. K/sub 2/Cr/sub 2/O/sub 7/ and (NH/sub 4/)/sub 2/MoO/sub 4/ increased the mutation rate of SM/sup r/ and try/sup +/ in both strains treated with either procedure. No marked differences in mutation rate were found between hcr/sup +/ and hcr/sup -/. After treatment with high concentrations of compounds one can imagine that a peroxidation state produced by these peroxides in the media might affect the killing and mutation induction. These results suggest the possibility that the mutagenesis of the metals relate to their atomic values, rather than the peroxidation state as far as these two compounds are concerned.

  7. Sensitivity of certain bacteria to antibiotics and irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Harsojo,; Andini, L S; Siagian, E G; Lina, M R; Zuleiha, S [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1981-07-01

    An experiment has been conducted to find vegetative forms of certain bacteria in Indonesia which are resistant to irradiation, the resistance of which will be compared to that of known radioresistant bacteria micrococcus radiodurans. To inactivate the vegetative forms of resistant bacteria to irradiation high doses are needed, while for storage purposes lower doses change the physical and chemical properties of the stored commodity are preferred. For this purpose the bacteria were irradiated in aerobic condition with gamma radiation doses of 0.1, 0.2 and 0.3 kGy, or treated with antibiotics e.g. tetracycline HCl or chloramphenicol with concentrations of 0.1, 0.2 and 0.3 ..mu..g/ml respectively. The results indicated that doses of 0.2 kGy and 0.1 ..mu..g/ml reduced the ability of the bacteria for multiplication.

  8. Presence of Pathogenic Bacteria and Viruses in the Daycare Environment.

    Science.gov (United States)

    Ibfelt, Tobias; Engelund, Eva Hoy; Permin, Anders; Madsen, Jonas Stenløkke; Schultz, Anna Charlotte; Andersen, Leif Percival

    2015-10-01

    The number of children in daycare centers (DCCs) is rising. This increases exposure to microorganisms and infectious diseases. Little is known about which bacteria and viruses are present in the DCC environment and where they are located. In the study described in this article, the authors set out to determine the prevalence of pathogenic bacteria and viruses and to find the most contaminated fomites in DCCs. Fifteen locations in each DCC were sampled for bacteria, respiratory viruses, and gastrointestinal viruses. The locations were in the toilet, kitchen, and playroom areas and included nursery pillows, toys, and tables, among other things. Coliform bacteria were primarily found in the toilet and kitchen areas whereas nasopharyngeal bacteria were found mostly on toys and fabric surfaces in the playroom. Respiratory viruses were omnipresent in the DCC environment, especially on the toys.

  9. Uptake of americium-241 by algae and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Geisy, J P; Paine, D

    1978-01-01

    Algae and bacteria are important factors in the transport and mobilization of elements in the biosphere. These factors may be involved in trophic biomagnification, resulting in a potential human hazard or environmental degradation. Although americium, one of the most toxic elements known, is not required for plant growth, it may be concentrated by algae and bacteria. Therefore, the availability of americium-241 to algae and bacteria was studied to determine their role in the ultimate fate of this element released into the environment. Both algae and bacteria concentrated americium-241 to a high degree, making them important parts of the biomagnification process. The ability to concentrate americium-241 makes algae and bacteria potentially significant factors in cycling this element in the water column. (4 graphs, numerous references, 3 tables)

  10. High resistance of some oligotrophic bacteria to ionizing radiation

    International Nuclear Information System (INIS)

    Nikitin, D.I.; Tashtemirova, M.A.; Pitryuk, I.A.; Sorokin, V.V.; Oranskaya, M.S.; Nikitin, L.E.

    1994-01-01

    The resistance of seven cultures of eutrophic and oligotrophic bacteria to gamma radiation (at doses up to 360 Gy) was investigated. The bacteria under study were divided into three groups according to their survival ability after irradiation. Methylobacterium organophilum and open-quotes Pedodermatophilus halotoleransclose quotes (LD 50 = 270 Gy) were highly tolerant. By their tolerance, these organisms approached Deinococcus radiodurans. Aquatic ring-shaped (toroidal) bacteria Flectobacillus major and open-quotes Arcocella aquaticaclose quotes (LD 5 = 173 and 210 Gy, respectively) were moderately tolerant. Eutrophic Pseudomonas fluorescens and Escherichia coli (LD 50 = 43 and 38 Gy, respectively) were the most sensitive. X-ray microanalysis showed that in tolerant bacteria the intracellular content of potassium increased and the content of calcium decreased after irradiation. No changes in the element composition of the eutrophic bacterium E. coli were detected. Possible mechanisms of the resistance of oligotrophic bacteria to gamma radiation are discussed

  11. Physiological and genetics studies of highly radiation-resistant bacteria

    International Nuclear Information System (INIS)

    Keller, L.C.

    1981-01-01

    The phenomenon of radiation resistance was studied using micrococci and Moraxella-Acinetobacter capable of surviving very high doses of gamma radiation which were isolated from foods. Physiological age, or growth phase, was found to be an important factor in making comparisons of radiation-resistance among different bacteria and their mutants. Radiation-resistant bacteria were highly resistant to the lethal effect of nitrosoguanidine used for mutagenesis. Studies of relative resistance of radiation-resistant bacteria, radiation-sensitive mutants, and nonradiation-resistant bacteria to killing by different chemical mutagens did not reveal a correlation between the traits of radiation resistance and mutagen resistance among different strains. Comparisons of plasmid profiles of radiation-resistant bacteria and selected radiation-sensitive mutants suggested the possibility that plasmids may carry genes involved in radiation resistance

  12. Natural soil reservoirs for human pathogenic and fecal indicator bacteria

    Science.gov (United States)

    Boschiroli, Maria L; Falkinham, Joseph; Favre-Bonte, Sabine; Nazaret, Sylvie; Piveteau, Pascal; Sadowsky, Michael J.; Byappanahalli, Muruleedhara; Delaquis, Pascal; Hartmann, Alain

    2016-01-01

    Soils receive inputs of human pathogenic and indicator bacteria through land application of animal manures or sewage sludge, and inputs by wildlife. Soil is an extremely heterogeneous substrate and contains meso- and macrofauna that may be reservoirs for bacteria of human health concern. The ability to detect and quantify bacteria of human health concern is important in risk assessments and in evaluating the efficacy of agricultural soil management practices that are protective of crop quality and protective of adjacent water resources. The present chapter describes the distribution of selected Gram-positive and Gram-negative bacteria in soils. Methods for detecting and quantifying soilborne bacteria including extraction, enrichment using immunomagnetic capture, culturing, molecular detection and deep sequencing of metagenomic DNA to detect pathogens are overviewed. Methods for strain phenotypic and genotypic characterization are presented, as well as how comparison with clinical isolates can inform the potential for human health risk.

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

    International Nuclear Information System (INIS)

    Sanders, S.W.; Maxcy, R.B.

    1979-01-01

    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 25 0 C 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

  14. Roseobacter-clade bacteria as probiotics in marine larvaeculture

    DEFF Research Database (Denmark)

    Grotkjær, Torben

    Disease caused by fish pathogenic bacteria can cause large scale crashes in marine fish larval rearing units. One of the biggest challenges for aquaculture is the management of these bacterial outbreaks. Vaccines can be admitted to fish but only the juvenile and the adult fish because they need...... to have a mature immune system. This means that the larvae of the fish, until they are 2-3 weeks old are more prone to bacterial infections. A short term solution is antibiotics but this leaves way for the selection for antibiotic resistance among the pathogenic bacteria, which again can be transferred...... to human pathogens. Alternatives are therefore needed and one could be the use of probiotic bacteria. Marine bacteria from the Roseobacter clade (Phaeobacter inhibens) have shown great potential as probiotic bacteria, and we have hypothesized that they could be used to antagonize pathogenic fish...

  15. 3D printing of bacteria into functional complex materials.

    Science.gov (United States)

    Schaffner, Manuel; Rühs, Patrick A; Coulter, Fergal; Kilcher, Samuel; Studart, André R

    2017-12-01

    Despite recent advances to control the spatial composition and dynamic functionalities of bacteria embedded in materials, bacterial localization into complex three-dimensional (3D) geometries remains a major challenge. We demonstrate a 3D printing approach to create bacteria-derived functional materials by combining the natural diverse metabolism of bacteria with the shape design freedom of additive manufacturing. To achieve this, we embedded bacteria in a biocompatible and functionalized 3D printing ink and printed two types of "living materials" capable of degrading pollutants and of producing medically relevant bacterial cellulose. With this versatile bacteria-printing platform, complex materials displaying spatially specific compositions, geometry, and properties not accessed by standard technologies can be assembled from bottom up for new biotechnological and biomedical applications.

  16. Influence of disturbances on bacteria level in an operating room

    DEFF Research Database (Denmark)

    Brohus, Henrik; Hyldig, Mikkel; Kamper, Simon

    2008-01-01

    In operating rooms great effort is manifested to reduce the bacteria level in order to decrease the risk of infections. The main source of bacteria is the staff and the patient, thus, the resulting bacteria concentration is roughly speaking a combination of the ventilation system and the emission...... from the occupants. This study investigates the influence of two main disturbances in an operating room namely the door opening during the operation and the activity level of the staff. It is found that the frequent door opening in this case does not cause significant transport of air from outside...... the operating room to the wound area of the patient. However, a significant influence of the activity level on the bacteria emission and concentration is found. Counting the number of persons in an operating room to estimate the bacteria source strength is not sufficient, the corresponding activity level must...

  17. A porous silicon optical microcavity for sensitive bacteria detection

    International Nuclear Information System (INIS)

    Li Sha; Huang Jianfeng; Cai Lintao

    2011-01-01

    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (∼10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml -1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml -1 . The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  18. A porous silicon optical microcavity for sensitive bacteria detection

    Science.gov (United States)

    Li, Sha; Huang, Jianfeng; Cai, Lintao

    2011-10-01

    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (~10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml - 1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml - 1. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  19. A porous silicon optical microcavity for sensitive bacteria detection

    Energy Technology Data Exchange (ETDEWEB)

    Li Sha; Huang Jianfeng; Cai Lintao, E-mail: lt.cai@siat.ac.cn [CAS Key Lab of Health Informatics, Shenzhen Key Laboratory of Cancer Nanotechnology, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China)

    2011-10-21

    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak ({approx}10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml{sup -1} at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml{sup -1}. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  20. High motility reduces grazing mortality of planktonic bacteria

    DEFF Research Database (Denmark)

    Matz, Carsten; Jurgens, K.

    2005-01-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated...... size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 mum(3). Grazing mortality was lowest for cells of >0.5 mum(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (less than or equal to0.1 mum......(3), >50 mum s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing....