Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Filtros aplicados
Base de dados
Intervalo de ano de publicação
1.
Rev. esp. patol. torac ; 30(4): 224-230, dic. 2018. graf, tab
Artigo em Espanhol | IBECS | ID: ibc-182315

RESUMO

HIPÓTESIS Y OBJETIVO: partiendo de la hipótesis de que la reprogramación de los transposones en el cáncer nos puede orientar sobre su desarrollo, en este trabajo se pretende determinar qué transposones podrían servir de biomarcadores con futuros propósitos diagnósticos y pronósticos. Material y métodos: a partir de muestras congeladas de biopsias de adenocarcinoma de pulmón, se ha secuenciado ARN total del tejido tumoral y sano adyacente de ocho pacientes intervenidos en el Hospital Regional de Málaga. Se han analizado con un flujo de trabajo bioinformático específico que cuantifica y proporciona la expresión diferencial de los transposones cuando se compara el tejido sano y tumoral de cada paciente. Resultados: en este trabajo prospectivo, el nivel de transposición global no cambia entre el pulmón sano y el adenocarcinoma. Se han identificado siete transposones con expresión diferencial significativa: cinco se sobreexpresan en las células del adenocarcinoma y los otros dos se sobreexpresan en las células sanas del pulmón. Todos los que son de la clase de retrovirus endógenos humanos (HERV) tienen un gran potencial como biomarcador al reprogramarse de la misma forma en todos los pacientes. Conclusión: el nivel de transposición en el cáncer de pulmón no está desregulado, sino reprogramado, y los transposones afectados por la reprogramación podrían considerarse biomarcadores en potencia


HYPOTHESIS AND OBJECTIVE: transposon reprogramming can be related to cancer development. The aim of this study is to determine the role of transposons in lung cancer and evaluate the posible role of transposon as a diagnostic and pronostic biomarkers in lung cáncer. MATERIAL AND METHODS: total RNA from lung adenocarcinome was sequenced. We analized RNA from tumor and adyacent healthy tissue from eight patients. By using a specific software the differential expression of the transposons in healthy and tumor tissue was analyzed in each patient. RESULTS: this prospective study shows that in our population, the overall transposition level does not change between the healthy and lung adenocarcinoma tissue. Seven transposons with significative differential expression have been found. Five were upregulated in adenocarcinoma cells, and the other two were upregulated in healthy lung cells. Those that belong to the human endogenous retroviruses (HERV) class show a high biomarker potential since they are reprogrammed in the same way in all patients. CONCLUSION: the transposition level in lung cancer is not deregulated but reprogrammed. Transposons affected by the reprogramming may be considered as potential biomarkers


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Adenocarcinoma de Pulmão/diagnóstico , Transposon Resolvases/análise , Elementos de DNA Transponíveis , Estudos Prospectivos , Toracoscopia , Análise de Dados
3.
Enferm. infecc. microbiol. clín. (Ed. impr.) ; 30(8): 492-499, oct. 2012. ilus
Artigo em Espanhol | IBECS | ID: ibc-104161

RESUMO

La virulencia bacteriana ha experimentado un largo proceso evolutivo dependiente de la relación huésped/patógeno, mientras que la resistencia antimicrobiana ha tenido una evolución muy diferente, más corta y cambiante debido a la presión biológica provocada por la introducción de los antimicrobianos en medicina por parte del hombre. Esta fuerte presión ha obligado a los microorganismos a adaptarse a esas condiciones cambiantes, adquiriendo o desarrollando nuevos mecanismos de resistencia de manera continuada, provocando cambios importantes en las funciones celulares, influyendo finalmente sobre la virulencia y el fitness bacterianos. Múltiples son los factores que pueden mediar en la relación entre virulencia y resistencia, y a menudo genes implicados en ambos fenómenos presentan el mismo medio de transporte y dispersión, como los plásmidos. Islas, integrones, transposones y otros elementos genéticos podrían también facilitar la coselección de genes implicados en virulencia y resistencia. La ganancia de resistencia puede afectar de manera muy variable a la virulencia, dependiendo principalmente de la especie bacteriana, del ambiente y del propio mecanismo de resistencia. En la revisión se exponen diferentes fenómenos en los cuales el mecanismo genético que proporciona una ventaja frente a los antimicrobianos afecta directamente a la virulencia y al fitness, como son cambios en la estructura de la pared celular, bombas de expulsión, porinas o sistemas reguladores de dos componentes. La coselección de factores de virulencia y resistencia antimicrobiana, así como la relativa facilidad de las bacterias para desarrollar mutaciones compensatorias, puede favorecer, especialmente en ambientes con una alta presión antibiótica, la aparición de clones prevalentes, virulentos y además con escasas opciones terapéuticas, lo que podría ser un importante problema de salud en un futuro cercano (AU)


While bacterial virulence has experienced a long host/pathogen-dependent evolutionary process, antimicrobial resistance has had a very different, shorting and changing evolution due to the biological pressure caused by the introduction of the antimicrobials in human medicine. This strong pressure has forced the microorganisms to adapt to these changing conditions, continuously acquiring or developing new resistance mechanisms, causing major changes in cellular functions and finally influencing the virulence and bacterial fitness. Multiple factors may mediate in the relationship between virulence and resistance. The genes often involved in both phenomena have the same transport and dispersion mediums. Islands, integrons, transposons and other genetic elements could also facilitate the combined selection of virulence and resistance genes. The increase in resistance can affect virulence in different ways, mainly depending on the bacterial species, the environment, and the mechanism of resistance. This review presents the different phenomena in which the genetic mechanism that provides an advantage over the antimicrobials directly affects the virulence and fitness, such as changes in the structure of the cellular wall, efflux pumps, porins or two-component regulatory systems. The co-selection of virulence and antimicrobial resistance factors and the relative ease of bacteria to develop compensatory mutations can favour, particularly in environments with high antibiotic pressure, the emergence of prevalent clones. These can be virulent and with few treatment options, and could be a major health problem in the near future (AU)


Assuntos
Humanos , Bactérias/patogenicidade , Resistência Microbiana a Medicamentos/imunologia , Aptidão Genética , Virulência/imunologia , Fatores de Virulência/análise , Plasmídeos/imunologia , Elementos de DNA Transponíveis , Integrons , Porinas
4.
Int. microbiol ; 15(2): 69-78, jun. 2012. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-102995

RESUMO

The mechanisms of cadmium, cobalt and zinc resistance were characterized in the plant-growth-promoting bacterium Gluconacetobacter diazotrophicus PAl 5. The resistance level of the wild-type strain was evaluated through the establishment of minimum inhibitory concentrations (MIC) of the soluble compounds CdCl2·H2O, CoCl2·6H2O and ZnCl2. Gluconacetobacter diazotrophicus PAl 5 was resistant to high concentrations of Cd, Co and Zn, with MICs of 1.2, 20 and 20 mM, respectively. Screening of an insertion library from transposon EZ-Tn5 in the presence of ZnO revealed that the mutant GDP30H3 was unable to grow in the presence of the compound. This mutant was also highly sensitive to CdCl2·H2O, CoCl2·6H2O and ZnCl2. Molecular characterization established that the mutation affected the czcA gene, which encodes a protein involved in metal efflux. In silico analysis showed that czcA is a component of the czcCBARS operon together with four other genes. This work provides evidence of the high tolerance of G. diazotrophicus PAl 5 to heavy metals and that czc is a determinant for metal resistance in this bacterium (AU)


No disponible


Assuntos
Gluconacetobacter/crescimento & desenvolvimento , Metais Pesados/farmacocinética , Cobalto , Zinco , Cádmio , Elementos de DNA Transponíveis
5.
Diagn. prenat. (Internet) ; 23(2): 56-66, abr.-jun. 2012.
Artigo em Espanhol | IBECS | ID: ibc-100382

RESUMO

El desarrollo en los últimos años de las denominadas tecnologías de secuenciación masiva permite actualmente obtener millones de secuencias de ADN a una velocidad sin precedentes y a un coste cada vez más reducido. Estas tecnologías están permitiendo la consecución de logros científicos trascendentales, con la identificación de nuevos genes y la resolución de las bases genéticas de enfermedades mendelianas a la cabeza. Su potencial ha permitido el desarrollo de nuevas aplicaciones y pruebas biológicas que van a revolucionar, en un futuro próximo, el diagnóstico postnatal y prenatal de enfermedades genéticas. En el presente artículo se ofrece una visión general de la tecnología y se examinan sus ventajas e inconvenientes respecto a métodos convencionales así como algunas de las principales estrategias, incluyendo métodos de estrategias de diagnóstico prenatal dirigidas a la detección de aneuploidías y síndromes de deleción/duplicación(AU)


The development in the recent years of the so-called next generation sequencing technologies based on massive parallel methods currently allows the production of millions of DNA sequences at an unprecedented speed with an increasing reduced cost per nucleotide. These technologies are producing very significant scientific achievements, with the identification of new genes and the resolution of the genetic basis of Mendelian diseases at the forefront. The potential of this technology is being used to create new applications and biological tests that are soon going to revolutionise the pre- and postnatal diagnosis of genetic disorders. In this paper we provide a general overview of the technology, examining its advantages and disadvantages in comparison with conventional strategies, as well as some of the main applicactions, including prenatal diagnosis strategies aimed at detecting aneuploidies and deletion/duplication syndromes(AU)


Assuntos
Humanos , Feminino , Gravidez , Diagnóstico Pré-Natal/instrumentação , Diagnóstico Pré-Natal/métodos , Testes Genéticos/instrumentação , Testes Genéticos/tendências , Elementos de DNA Transponíveis/genética , Doenças Genéticas Inatas/diagnóstico , Diagnóstico Pré-Natal/normas , Diagnóstico Pré-Natal , Testes Genéticos/métodos , Testes Genéticos , Cuidado Pós-Natal/métodos
6.
Int. microbiol ; 14(1): 51-58, mar. 2011. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-94606

RESUMO

This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem (AU)


No disponible


Assuntos
Humanos , Carbapenêmicos/farmacocinética , Resistência Microbiana a Medicamentos , Pseudomonas aeruginosa/genética , Testes de Sensibilidade Microbiana/métodos , Infecções por Pseudomonas/microbiologia , Elementos de DNA Transponíveis
7.
Int. microbiol ; 13(4): 195-206, dic. 2010. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-96708

RESUMO

This work describes a medium-based screening method for selecting microbial biocontrol agents against Erwinia amylovora based on the degradation of a specific growth factor. Erwinia amylovora, the causal agent of the devastating fire blight disease, requires nicotinic acid or nicotinamide as an essential growth factor. Potential biocontrol agents are either selected for antimicrobial production in plate or directly on immature pears or apple blossoms. In this work, we have attempted to streamline the selection of a new potential biocontrol agent with a lower risk of non-target effects by isolation based on the ability to degrade nicotinic acid in vitro, using therefore few plant materials. A total of 735 bacteria and 1237 yeast were isolated from apple blossoms and pre-screened for nicotinic acid-degradation. Pseudomonas rhizosphaerae strain JAN was able to degrade both nicotinic acid and nicotinamide. Mutants deficient in this ability were constructed. JAN, but not the mutants, controlled E. amylovora on pear slices. On detached apple blossoms, JAN colonized apple hypanthia and strongly suppressed E. amylovora growth. Under greenhouse conditions, JAN was more effective in controlling blossom blight than P. fluorescens A506, a commercial biocontrol agent of fire blight unable to degrade nicotinic acid and nicotinamide (AU)


No disponible


Assuntos
Ácidos Nicotínicos/metabolismo , Pseudomonas/genética , Pseudomonas/isolamento & purificação , Pseudomonas/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Erwinia amylovora/crescimento & desenvolvimento , Erwinia amylovora/metabolismo , Elementos de DNA Transponíveis , Flores/microbiologia , Frutas/microbiologia , Malus/microbiologia , Mutagênese Insercional , Filogenia , Brotos de Planta/microbiologia , Pyrus/microbiologia
8.
Int. microbiol ; 11(2): 101-110, jun. 2008. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-67271

RESUMO

A novel insertion sequence (IS), ISPst9, from Pseudomonas stutzeri AN10 was cloned and characterized. ISPst9 is a typical bacterial IS, consisting of a 2472-bp element flanked by 24-bp perfect inverted repeats that generates 8-bp AT-rich target duplications upon insertion. The sequence also contains a gene that encodes an active transposase (TnpA) with significant amino acid identity to members of the ISL3 family. Southern blot analysis of digested genomic DNA of strain AN10 and its 4-chlorosalicylate-degrading derivative strain AN142 demonstrated that native ISPst9 transposes in multiple copies, with one of them responsible for the nahH insertional inactivation observed in strain AN142. Precise excision of ISPst9 yielded NahH+ revertants of AN142 at high frequencies (up to 10-6). In vivo transposition, mainly in multiple copies, of an ISPst9 derivative containing a KmR cassette cloned into a suicide vector was also demonstrated. Hybridization experiments carried out with different strains of P. stutzeri and with 292 phylogenetically distinct environmental isolates suggested that the presence of an ISPst9-like IS occurs in diverse bacteria together with the presence of aromatic hydrocarbon-degrading determinants (AU)


No disponible


Assuntos
Pseudomonas stutzeri/genética , Proteína Receptora de AMP Cíclico , Elementos de DNA Transponíveis , Elementos Nucleotídeos Longos e Dispersos
9.
Int. microbiol ; 10(2): 147-150, jun. 2007. ilus
Artigo em Inglês | IBECS | ID: ibc-056705

RESUMO

Alterations in the erm(A) regulatory region of six clinical isolates of Staphylococcus epidermidis and one of Staphylococcus haemolyticus displaying a constitutive resistance phenotype were investigated. A novel deletion of 10 bp with respect to the corresponding sequence of Tn554 was identified in the attenuator of a constitutively expressed erm(A) gene of one of the S. epidermidis isolates. Thus far, this is the smallest deletion conferring constitutive resistance in the translational attenuator of erm(A) in a naturally occurring S. epidermidis strain of human origin (AU)


No disponible


Assuntos
Staphylococcus epidermidis/genética , Antibacterianos/farmacologia , Metiltransferases/genética , Macrolídeos/farmacologia , Proteínas de Bactérias/genética , Staphylococcus epidermidis/isolamento & purificação , Staphylococcus epidermidis/patogenicidade , Deleção Cromossômica , Elementos de DNA Transponíveis/genética , Sequência de Bases
10.
Int. microbiol ; 7(2): 95-104, jun. 2004. ilus, tab, graf, tab, ilus
Artigo em Inglês | IBECS | ID: ibc-98750

RESUMO

The use of resistant cultivars is one of the most practical and costefficient strategies for managing plant diseases. However, the efficiency of resistant cultivars in disease management is limited by pathogenic variability in pathogen populations. Knowledge of the evolutionary history and potential of the pathogen population may help to optimize the management of disease-resistance genes, irrespective of the breeding strategy used for their development. In this review, we examine the diversity in virulence phenotypes of Fusarium oxysporum f. sp. ciceris, the causal agent of Fusarium wilt of chickpeas, analyze the genetic variability existing within and among those phenotypes, and infer a phylogenetic relationship among the eight known pathogenic races of this fungus. The inferred intraspecific phylogeny shows that each of those races forms a monophyletic lineage. Moreover, virulence of races to resistant chickpea cultivars has been acquired in a simple stepwise pattern, with few parallel gains or losses. Although chickpea cultivars resistant to Fusarium wilt are available, they have not yet been extensively deployed, so that the stepwise acquisition of virulence is still clearly evident (AU)


La utilización de cultivares resistentes es una de las estrategias más prácticas y económicas para el control de las enfermedades de las plantas. No obstante, la eficiencia de los cultivares resistentes en dicho control está limitada por la variabilidad patogénica en las poblaciones de los patógenos. El conocimiento de la historia y el potencial evolutivo de las poblaciones de los patógenos puede ayudarnos a optimizar el uso de los genes de resistencia contra enfermedades, independientemente de la estrategia de mejora genética del huésped empleada para su desarrollo. En esta revisión examinamos la diversidad de los fenotipos de virulencia en Fusarium oxysporum f.sp. ciceris, el agente causal de la Fusariosis vascular del garbanzo, analizamos la variabilidad genética intra- e interfenotípica, e inferimos la relación filogenética existente entre las ocho razas patógénicas conocidas de este hongo. La filogenia intraespecífica inferida muestra que cada una de estas ocho razas constituye un linaje monofilético. Además, las razas virulentas sobre los cultivares resistentes de garbanzo han adquirido esta capacidad según un modelo gradual simple, con pocas ganancias o pérdidas paralelas de virulencia. A pesar de que existen cultivares de garbanzo resistentes a la Fusariosis vascular, la utilización restringida de ellas realizada hasta ahora permite que la adquisición gradual de virulencia sea aún claramente perceptible (AU)


Assuntos
Fusarium/genética , Doenças das Plantas/microbiologia , Cicer , Fusariose/genética , Fusarium/classificação , Fatores de Virulência/genética , Elementos de DNA Transponíveis/genética , Cicer/microbiologia
11.
Int. microbiol ; 7(1): 3-12, mar. 2004. graf
Artigo em Inglês | IBECS | ID: ibc-33215

RESUMO

IS200 is a mobile element found in a variety of eubacterial genera, such as Salmonella, Escherichia, Shigella, Vibrio, Enterococcus, Clostridium, Helicobacter, and Actinobacillus. In addition, IS200-like elements are found in archaea. IS200 elements are very small (707-711 bp) and contain a single gene. Cladograms constructed with IS200 DNA sequences suggest that IS200 has not spread among eubacteria by horizontal transfer; thus it may be an ancestral component of the bacterial genome. Self-restraint may have favored this evolutionary endurance; in fact, unlike typical mobile elements, IS200 transposes rarely. Tight repression of transposase synthesis is achieved by a combination of mechanisms: inefficient transcription, protection from impinging transcription by a transcriptional terminator, and repression of translation by a stem-loop mRNA structure. A consequence of IS200 self-restraint is that the number and distribution of IS200 elements remain fairly constant in natural populations of bacteria. This stability makes IS200 a suitable molecular marker for epidemiological and ecological studies, especially when the number of IS200 copies is high. In Salmonella enterica, IS200 fingerprinting is extensively used for strain discrimination (AU)


IS200 es un elemento móvil presente en una variedad de géneros de eubacterias como Salmonella, Escherichia, Shigella, Vibrio, Enterococcus, Clostridium, Helicobacter y Actinobacillus. También se encuentran elementos similares a IS200 en arqueas. Los elementos IS200 son muy pequeños (707-711 pb) y contienen un solo gen. Los cladogramas construidos a partir de las secuencias de DNA de IS200 sugieren que este elemento no ha sufrido transferencia horizontal dentro de las eubacterias; por tanto, IS200 puede ser un componente ancestral del genoma bacteriano. La longevidad evolutiva de IS200 puede haber sido favorecida por su baja frecuencia de transposición, que contrasta con el comportamiento de muchos elementos móviles. En IS200, la síntesis de transposasa está reprimida por varios mecanismos: transcripción ineficaz, terminación de los transcritos iniciados en promotores foráneos y represión de la traducción por una estructura secundaria («tallo-lazo») de mRNA. Como consecuencia de este autocontrol, tanto el número como la distribución de elementos IS200 se mantienen relativamente constantes en las poblaciones naturales de bacterias. Esta estabilidad convierte a IS200 en un marcador adecuado para estudios epidemiológicos o ecológicos, especialmente cuando el número de copias de IS200 es alto. En Salmonella enterica, los perfiles de IS200 se usan habitualmente para la tipificación y discriminación de cepas (AU)


Assuntos
DNA Bacteriano , Bactérias/genética , Elementos de DNA Transponíveis/genética , Archaea/genética , Sequência de Bases , Evolução Biológica
12.
Artigo em Espanhol | IBECS | ID: ibc-4964

RESUMO

Se investigó la asociación de los determinantes de resistencia a antibióticos MLSB (macrólidos, lincosamidas, estreptogramina B)-erm(B) y mef(A)) con los determinantes tet(M) (resistencia a tetraciclina y minociclina), catpC194 (resistencia a cloranfenicol), aph3´-III (resistencia a kanamicina y aminoglucósidos relacionados) con el fin de estudiar como se seleccionan las resistencias en Streptococcus pneumoniae. Los genes tet(M) y catpC194 se encuentran asociados al gen de resistencia erm(B), mientras que el gen aph3´-III estaba presente en bajo porcentaje. El transposón Tn1545 es el vector responsable de la diseminación de estos genes de resistencia. Por el contrario, el gen mef(A) no está relacionado con los determinantes tet(M), catpC194 y aph3´-III y parece que se transfiere mediante un transposón conjugativo diferente a Tn1545. La coexistencia de diferentes genes de resistencia en el mismo transposón conjugativo es de gran importancia desde el punto de vista de la salud pública, puesto que el tratamiento antibiótico, con cualquiera de los antibióticos a los que confiere resistencia el transposón, podría seleccionar cepas multirresistentes. (AU)


Assuntos
Genes Bacterianos , Streptococcus pneumoniae , Tetraciclina , Metiltransferases , Proteínas de Membrana , Proteínas de Bactérias , Antibacterianos , Cloranfenicol , Elementos de DNA Transponíveis , Resistência Microbiana a Medicamentos , Canamicina , Eritromicina , Ligação Genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA