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Pesquisa : D08.811.682.647 [Categoria DeCS]
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Id: lil-606123
Autor: Rodríguez Cheang, Anar Janet; Trujillo Cerón, Iván David; Bringas Yaremis, Felipe; Rojas Badía, Marcia María; Manzano Castañeda, Julia; Heydrich Pérez, Mayra.
Título: Caracterización fisiológica de la comunidad microbiana endófita de la caña de azúcar / Physiological characterization of sugarcane's endophytic microbial community
Fonte: Rev. colomb. biotecnol;7(1):66-75, jul. 2005. tab, graf.
Idioma: es.
Resumo: El uso desmedido de fertilizantes químicos nitrogenados y pesticidas ha traído graves consecuencias ambientales, por lo que se ha prestado gran atención al estudio de la microbiota nativa de los cultivos y sus beneficios a la planta, incluyendo la caña de azúcar. Este trabajo se realizó con el objetivo de caracterizar la microbiota nativa de la caña de azúcar. Se utilizaron 5 cepas bacterianas y 50 aislados provenientes del interior de este cultivo. Se determinó la actividad nitrogenasa y la influencia de la fuente de carbono, nitrógeno y el pH en la misma, mediante cromatografía gaseosa. Se detectó la producción de ácido indolacético por Dot-Immunobinding y el método de Salkowski. Del total de cepas y aislados, 19 mostraron actividad nitrogenasa, con valores entre 100 y 5000 //g/mL, y 6, Gluconacetobacter diazotrophicus PAl-5, Gluconacetobacter diazotrophicus 1-05, Gluconacetobacter diazotrophicus 4-02, aislado 17, aislado 30 y aislado 305; además, tienen la capacidad de producir AIA (valores entre 1,7 y 2,5 JMg/mL). Se demostró que las fuentes nutricionales y el pH del medio de cultivo influyen sobre la actividad nitrogenasa de las cepas representativas de la comunidad endófita.

Excessive application of chemical nitrogen fertilisers and pesticides has badly affected the environment. This has led to great interest being shown in studying a crop's native microbial community and its benefit for plants. This paper was thus aimed at characterising sugarcane's endophytic microbial community. 5 sugar cane strains and 50 isolates were used. Gas chromatography was used for measuring nitrogenase activity and the influence of carbon and nitrogen sources and pH on cultures. Indol acetic (IAA) production was detected by Dot-Immunobinding and Salkowski's method. These results show that 19 strains and isolates had nitrogenase activity, values ranging from 100 to 5000 /zg/mL; 6 of them produced IAA (values ranging from 1,7 to 2,5 //g/mL): Gluconacetobacter iazotrophicus PAl-5, Gluconacetobacter diazotrophicus 1-05, Gluconacetobacter diazotrophicus 4-02, 17, 30 and 305. It was demonstrated that culture medium nutrient sources and pH affectedthe nitrogenase activity of the strains representing the endophytic community.
Descritores: Nitrogenase
Uso de Praguicidas
Saccharum/efeitos adversos
Saccharum/microbiologia
Saccharum/toxicidade
-Ácido Hidroxi-Indolacético
Responsável: CO326 - Departamento de Biología


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Texto completo SciELO Chile
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Id: lil-448770
Autor: Banerjee, Meenakshi; Mishra, Shanoo; Chatterjee, Jhuma.
Título: Scavenging of nickel and chromium toxicity in Aulosira fertilissima by immobilization: effect on nitrogen assimilating enzymes
Fonte: Electron. j. biotechnol;7(3):13-14, Dec. 2004. ilus, tab, graf.
Idioma: en.
Resumo: The ubiquity of heavy metals in the biosphere results in the introduction of high amounts of toxic metals into the food chain from various sources. In the present study, one of the strongest nitrogen fixing cyanobacterium of the rice fields, Aulosira fertilissima, was subjected to nickel and chromium stress and the ameliorating effect of immobilization was investigated. Cell immobilization could protect the organism's growth against the toxicity of both heavy metals at LC50 as compared to lethal concentrations. The nitrate reductase activity in free cells treated with the metals was substantially inhibited but immobilized cells treated with 0.1 ppm nickel was not affected by the metal treatment. Cell immobilization also resulted in a significant protection against sub-lethal concentration of chromium but to a lesser degree than it did with sub- lethal levels of nickel. Control immobilized cells also had higher Nitrogenase activity than control free cells. Nickel and chromium addition markedly decreased the enzyme activity in free cells but immobilized cells exposed to sublethal concentrations of both metals could overcome this decrease. Glutamine synthetase showed similar response under immobilized conditions compared to free cells with both metals. The addition of algal filtrate in 3:1 ratio further increased the nitrogenase activity compared with immobilized cells treated with sublethal doses of both metals. Immobilization facilitated higher uptake of nickel as compared to chromium. The observations of the present study clearly demonstrate the protective effect of immobilization on Aulosira fertilissima against Nickel and chromium toxicity. Rice field ecosystem thus possess a bidirectional natural metal ameliorating system where Aulosira mats act as a naturally immobilized system and the decay of Aulosira along with other cyanobacteria act as natural chelators protecting the rice plants from deleterious effects of the heavy metals. Most importantly is...
Descritores: Cianobactérias/metabolismo
Cromo/metabolismo
Níquel/metabolismo
-Agricultura
Cianobactérias/enzimologia
Poluição Química da Água/prevenção & controle
Cromo/toxicidade
Glutamato-Amônia Ligase/metabolismo
Fixação de Nitrogênio
Níquel/toxicidade
Nitrato Redutase/metabolismo
Nitrogenase/metabolismo
Responsável: CL1.1 - Biblioteca Central


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Texto completo SciELO Brasil
Texto completo
Id: lil-349772
Autor: Barbosa, Heloiza R; Moretti, Marcos A; Thuler, Daniela S; Augusto, Elisabeth F. P.
Título: Nitrogenase activity of Beijerinckia derxii is preserved under adverse conditions for its growth
Fonte: Braz. j. microbiol;33(3):223-229, July-Sept. 2002. tab, graf.
Idioma: en.
Resumo: In order to evaluate the response of Beijerinckia derxii ICB-10 to different environmental factors, growth curves and specific nitrogenase activity were studied. Tested conditions were as follows: a) media with different pH values (2.5, 2.8, 4.2 and 5.7); b) medium supplemented with 230 æM aluminium sulphate; c) media with two different potassium phosphate concentrations (50 mM and 100 mM); d) shaken or still cultures; e) medium supplemented with 40 mM sodium thiosulphate. Growth curves and specific nitrogenase activity at pH 4.2 were closely similar to those for cultures at pH 5.7 (standard condition), whereas no growth occurred at pH 2.5. Changes in growth curves and/or specific nitrogenase activity were observed under the following conditions: I) pH 2.8 (decrease in initial CFU number, reduction of maximum specific growth rate, reduced number of generations and stimulation of nitrogenase activity), II) presence of aluminium (early death phase), III) 50 mM PO4(3-) (reduction of maximum specific growth rate), IV) 100 mM PO4(3-) (reduction of both number of generations and maximum specific growth rate as well as early death phase), V) low O2 availability (increasing nitrogenase activity), and VI) presence of thiosulphate (reduction of maximum specific growth rate; early death phase and high stimulation of nitrogenase activity). The data obtained showed the high variability of the cell growth response to environmental factors. Nitrogenase activity was always preserved even when population growth was affected
Descritores: Bactérias Aeróbias Gram-Negativas/crescimento & desenvolvimento
Bactérias Aeróbias Gram-Negativas/isolamento & purificação
Ensaios Enzimáticos Clínicos
Técnicas In Vitro
Fixação de Nitrogênio
Nitrogenase
-Meio Ambiente
Variação Genética
Métodos
Tipo de Publ: Estudos de Avaliação
Responsável: BR32.1 - Serviço de Biblioteca e Informação Biomédica


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Texto completo SciELO Brasil
Texto completo
Id: lil-297393
Autor: Barbosa, Heloíza R; Thuler, Daniela Strauss; Shirakawa, Márcia Aiko; Miyasaka, Natália R. S.
Título: "Beijerinckia derxii" stimulates the viability of non-N(2)-fixing bacteria in nitrogen-free media
Fonte: Braz. j. microbiol;31(3):168-73, jul.-set. 2000. tab, graf.
Idioma: en.
Resumo: The interactions between the nitrogen-fixing microorganism "Beijerinckia derxii" with two non-diazotrophic bacteria, either "Escherichia coli" or a faculty sulphur-oxidizing chemolitroph, were studied in mixed cultures. Direct and indirect contact between "B. derxii" and "E. coli" were tested. "B. derxii" increased CFU numbers and/or maintained the viability of the non-diazotrophic bacteria, but neither growth nor nitrogenase activity of the nitrogen-fixing bacterium were affected by either partner
Descritores: Bactérias Gram-Negativas/patogenicidade
Técnicas In Vitro
Infecções Bacterianas/microbiologia
Nitrogenase/análise
-Compostos de Nitrogênio/análise
Tipo de Publ: Relatório Técnico
Responsável: BR32.1 - Serviço de Biblioteca e Informação Biomédica


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Id: lil-280141
Autor: Sá, Nadja M. Horta de; Scotti, Maria Rita M. M. L; Paiva, Edilson; Franco, Avílio A; Döbereiner, Johanna.
Título: Seleçäo e caracterizaçäo de estirpes de rhizobium estáveis e capazes de fixar nitrogênio em feijäo(phaseolus vulgaris L.) / Selection and characterization of rhizobium spp.strains stable and capable in fixing nitrogen in bean(phaseolus vulgaris L.)
Fonte: Rev. microbiol;24(1):38-48, mar. 1993. tab, graf.
Idioma: pt.
Resumo: resumo:Determinou-se a variabilidade na capacidade de fixaçäo de N2, através de testes de reduçäo de acetileno em nódulos formados por estirpes de Rhizobium, antes e após exposiçäo das bactérias "in vitro" à temperaturas elevadas (38-39ºC).Nódulos formados tanto por estirpes de R.leguminosarum bv.phaseoli como R.tropici mais tolerantes a altas temperaturas quando inoculadas em feijäo, näo sofreram alteraçöes nas características simbióticas tais como, atividade de nitrogenase, peso seco de planta e nitrogênio total fixado.O padräo de proteínas(eletroforese SDS-PAGE) diferenciou estirpes entre e dentro das espécies.A hibridizaçäo do DNA total usando "nifprob" marcada via "nick translation"(biotina 14 dATP), quando a digestäo foi efetuada com EcoRI, diferenciou a espécie de R.leguminosarumbv.phaseoli de R.tropici.Foi observado polimorfismo entre as estirpes de R.leguminosarum bv.phaseoli após digestäo com Bam HI e entre R.leguminosarum bv.phaseoli e R.tropici após a digestäo com Hind III.Näo foram detectadas alteraçöes nos padröes protéicos ou genômicos e na atividade da nitrogenase da mesma estirpe antes e após crescimento a temperaturas elevadas, indicando que as estirpes de ambas as espécies(R.leguminosarum bv.phaseoli e R.tropici), tolerantes a altas temperaturas säo também mais estáveis geneticamente
Descritores: Fabaceae
Genoma Bacteriano
Técnicas In Vitro
Nitrogenase/efeitos adversos
Rhizobium leguminosarum
Tipo de Publ: Estudo Comparativo
Responsável: BR734.1 - Biblioteca Central Cesar Lattes - BCCL


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Machado, I. M. P
Id: lil-188440
Autor: Machado, I. M. P; Yates, M. G; Machado, H. B; Souza, E. M; Pedrosa, F. O.
Título: Cloning and sequencing of the nitrogenase structural genes nifHDK of Herbaspirillum seropedicae
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;29(12):1599-602, Dec. 1996. ilus.
Idioma: en.
Resumo: The nitrogenase structural genes (nifHDK) of the endophytic diazotroph Herbaspirillum seropedicae were isolated from a genomic bank by plate hybridization. Sequence analysis of the DNA showed a consensus promoter region upstream from the nifH gene containing a -24/-12 type promoter together with NifA- and integration host factor (IHF)- binding sites. The derived protein sequences of NifH, NifD and NifK contained conserved cysteine residues for binding iron-sulfur clusters and the iron-molybdenum cofactor. These protein sequences showed the strongest similarities to the nifHDK gene products of the symbiotic diazotroph Bradyrhizobium japonicum (93.5 per cent, 91.3 per cent and 83.3 per cent, respectively), the plant-associated diazotrophAzospirillum brasilense (90.0 per cent, 83.7 per cent and 75.1 per cent, respectively) and to Thiobacillus ferrooxidans (91.0 per cent, 83.4 per cent and 81.1 per cent, respectively) of the same phylogenetic group of the protobacteria.
Descritores: Fixação de Nitrogênio
Nitrogenase/genética
-Sequência de Aminoácidos
Sequência de Bases
Cisteína/isolamento & purificação
Genes Bacterianos
Dados de Sequência Molecular
Fases de Leitura Aberta
Análise de Sequência de DNA
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Id: lil-187854
Autor: Parra Campos, Víctor; Escobar Gutiérrez, Alejandro; Domínguez López, María Lilia; Cancino Díaz, Mario; Burgos Vargas, Rubén; Granados Arreola, Julio; Jiménez Zamudio, Luis; García Latorre, Ethel.
Título: Antibody response to nitrogenase-positive and-negative Klebsiella pneumoniae strains in juvenile-onset ankylosing spondylitis patients and their first degree relatives: lack of differential recognition of the bacterial nitrogenase
Fonte: Rev. latinoam. microbiol;38(2):121-7, abr.-jun. 1996. ilus, tab.
Idioma: en.
Resumo: En la búsqueda de las consecuencias patogénicas del mimetismo molecular entre la nitrigenasa de Klebsiella pneumoniae y el antígeno HLA-B27, se determinó la presencia de anticuerpos contra extractos completos de cepas de K. pneumoniae nitrogenasa positiva y negativa en el suero de individuos pertenecientes a 16 familias con casos de espondilitis anquilosante juvenil. Se hizo una selección inicial de cepas de K. pneumoniae productoras e nitrogenasa a partir de 31 aislamientos clínicos. Se buscó la mejor cepa productora de nitrogenasa así como una no productora y mediante inmunoelectrotransferencia se hizo un análisis del suero de 82 sujetos, de los cuales 55 fueron HLA-B27 positivos y de éstos, 26 mostraron alguna manifestación clínica. Aunque los patrones electroforéticos fueron diferentes con ambas cepas, no hubo reconocimiento distintivo o diferencial de las proteínas de 30 a 40 kDa donde se ubica el sub-componente de la nitrogenasa que tiene la secuencia QTDRED que se comparte con la molécula HLA-B27. Por otra parte, se encontró un fuerte reconocimiento de una proteína de 60 kDa (p60Kp) en el 75 por ciento de los sujetos HLA.B27 positivos, independientemente de su estado clínico. Actualmente se están realizando estudios para determinar la naturaleza de dicha molécula y su papel en la patogenia de la espondilitis anquilosante
Descritores: ANTIGENO HLA-BABORTION, EUGENIC
Klebsiella pneumoniae
Nitrogenase
Espondilite Anquilosante
Limites: Seres Humanos
Responsável: MX1.1 - CENIDSP - Centro de Información para Decisiones en Salud Pública


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Langenbach, Tomaz
Id: lil-94119
Autor: Langenbach, Tomaz; Nascimiento, Alcina; Sarpa, Michele.
Título: Influence of heavy metals on nitrogen fixation and growth of azospirillum strains
Fonte: Rev. latinoam. microbiol;30(2):139-42, abr.-jun. 1988. ilus.
Idioma: en.
Resumo: Se efectos del Hg, Cd, zn y Pb en el crecimiento y actividad de nitrogenasa de Azospirillum spp, en un medio químicamente definido. A concentraciones de metal de 0.1 y l ppm se inhibió la actividad de nitrogenasa y el crecimiento, respectivamente. El Pb inhibe el 25% de lactividad de reducción de acetileno (ARA) con 1 ppmj, permaneciendo constante inclcusive con incrementos concentración. el crecimiento no se inhibió por el óxido ni el cloruro de plomo. El Zn inhibe el 50% de ARA con 1 ppm, permaneciendo constante con incrementos de concentración. Por otro lado el crecimiento se inhibió continuamente con incrementos de concentración. En contraste, con Hg y Cd, se inhibió el 50% de ARA a concentraciones menores (0.4 ppm) que las necesarias para inhibir el 50% de crecimiento (2.4 y 6 ppm, respectivamente). Se observó resistencia cuando se incubó 24hs. de crecimiento con Cd; la inhibición al 50% de ARA necesita una concentración de Cd de 18 ppm, valor que es mucho más alto comparado con 1 hora de incubación (0.4 ppm). Sin embargo, la enzima es más sensible al Cd que el crecimiento. Se discute la importancia de estos hallazgos en la contaminación ambiental
Descritores: Poluição Ambiental
Metais
Fixação de Nitrogênio
Nitrogenase
Responsável: MX1.1 - CENIDSP - Centro de Información para Decisiones en Salud Pública



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