RESUMO
Resumen Introducción. Los factores de virulencia de las cepas de Vibrio cholerae no-O1, no-O139 no son claramente conocidos. La cepa de origen septicémico NN1 Vibrio cholerae no-O1, no-O139 fue secuenciada previamente mediante la plataforma Illumina, detectándose en su genoma un fragmento de la isla de patogenicidad VPaI-7 de V. parahaemolyticus. Objetivo: detectar los genes de virulencia vcsN2, vcsC2, vcsV2, vspD, toxR2 y vopF en cepas chilenas clínicas de V. cholerae no-O1, no-O139. Material y Métodos: Un total de 9 cepas chilenas de origen clínico de Vibrio cholerae no-O1, no-O139 aisladas entre 2006-2012 fueron analizadas mediante ensayos de reacción de polimerasa en cadena (RPC, en inglés PCR) convencional para los genes de secreción tipo III codificados en dicha isla: vcsN2, vcsC2, vcsV2, vspD, toxR2 y vopF. Adicionalmente se determinó la presencia de los genes de virulencia hylA y rtxA. Además, se realizaron ensayos de repetitive element palindromic PCR (REP-PCR) y Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Resultados: la mayoría (6/9) de las cepas chilenas de V. cholerae no-O1, no-O139 contiene todos los genes de secreción tipo III vcsN2, vcsC2, vcsV2, vspD, toxR2 y vopF, codificados en una isla de patogenicidad. Además, el total de las cepas (9/9) contiene los genes de virulencia hylA y rtxA. Conclusión: Estos resultados sugieren fuertemente la posibilidad que dichas cepas posean un potencial de virulencia importante en seres humanos.
Backgound: The virulence factors of the Vibrio cholerae non-O1, non-O139 strains are not clearly known. The strain of septicemic origin NN1 Vibrio cholerae non-O1, non-O139 was sequenced previously by the Illumina platform. A fragment of the pathogenicity island VPaI-7 of V. parahaemolyticus was detected in its genome. Aim: To detect the virulence genes vcsN2, vcsC2, vcsV2, vspD, toxR2 y vopF in Chilean strains of V. cholerae non-O1, non-O139. Methods: A total of 9 Chilean strains of clinical origin of Vibrio cholerae non-O1, non-O139 isolated between 2006-2012 were analyzed by conventional PCR assays for type III secretion genes encoded on that island: vcsN2, vcsC2, vcsV2, vspD, toxR2 and vopF. Additionally, the presence of the virulence genes hylA and rtxA was determined. In addition, REP-PCR and ERIC-PCR assays were performed. Results: most (6/9) Chilean V. cholerae non-O1, non-O139 strains contain the type III secretion genes vcsN2, vcsC2, vcsV2, vspD, toxR2 and vopF, encoded in an island of pathogenicity. In addition, all (9/9) the strains contain the virulence genes hylA and rtxA. Conclusion: These results strongly suggest the possibility that those strains possess an important virulence potential in humans.
Assuntos
Humanos , Proteínas de Bactérias/genética , Fatores de Transcrição/genética , Vibrio cholerae/genética , Fatores de Virulência/genética , Vibrio cholerae não O1/genética , Ilhas Genômicas/genética , Proteínas de Ligação a DNA/genética , Sistemas de Secreção Tipo III/genética , Toxinas Bacterianas/genética , Vibrio cholerae/isolamento & purificação , Vibrio cholerae/patogenicidade , Chile , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Vibrio cholerae não O1/isolamento & purificação , Vibrio cholerae não O1/patogenicidade , Proteínas Hemolisinas/genéticaRESUMO
ABSTRACT Gastric cancer is one of the main causes of death by cancer in the world and the infection with Helicobacter pylori is one of the main risk factors associated with its appearance. Helicobacter pylori is a bacterium that colonizes the gastric mucosa, infecting about half of the world´s population. The pathological effects caused by infections with H. pylori greatly depend on an IV type secretion system encoded in the cag pathogenicity island (cagPAI). In this review, we describe the composition of the cagPAI, the alterations of cellular signaling pathways mediated by cagPAI which regulate oncogenic cellular responses that may increase the risk of malignant transformation associated with the infection and the importance of polymorphisms in cagPAI genes as potential markers of progression to gastric cancer.
RESUMEN El cáncer gástrico es una de las principales causas de muerte por cáncer en el mundo y la infección con Helicobacter pylori es uno de los principales factores de riesgo, asociados a su aparición. H. pylori es una bacteria que coloniza la mucosa gástrica, infectando alrededor de la mitad de la población mundial. Los efectos patológicos ocasionados por la infección con H. pylori dependen, en buena parte, de un sistema de secreción tipo IV, codificado en el islote de patogenicidad cag (cagPAI). En esta revisión, se describe la composición del cagPAI, la alteración de las vías de señalización celular mediadas por el cagPAI, que regulan respuestas celulares oncogénicas, que pueden incrementar el riesgo de transformación maligna asociada a la infección y la importancia de los polimorfismos en genes del cagPAI, como posibles marcadores de progresión a cáncer gástrico.
RESUMO
Microbial solubilizing of metals in acid environments is successfully used in industrial bioleaching of ores or biomining to extract metals such as copper, gold, uranium and others. This is done mainly by acidophilic and other microorganisms that mobilize metals and generate acid mine drainage or AMD, causing serious environmental problems. However, bioremediation or removal of the toxic metals from contaminated soils can be achieved by using the specific properties of the acidophilic microorganisms interacting with these elements. These bacteria resist high levels of metals by using a few "canonical" systems such as active efflux or trapping of the metal ions by metal chaperones. Nonetheless, gene duplications, the presence of genomic islands, the existence of additional mechanisms such as passive instruments for pH and cation homeostasis in acidophiles and an inorganic polyphosphate-driven metal resistance mechanism have also been proposed. Horizontal gene transfer in environmental microorganisms present in natural ecosystems is considered to be an important mechanism in their adaptive evolution. This process is carried out by different mobile genetic elements, including genomic islands (GI), which increase the adaptability and versatility of the microorganism. This mini-review also describes the possible role of GIs in metal resistance of some environmental microorganisms of importance in biomining and bioremediation of metal polluted environments such as Thiomonas arsenitoxydans, a moderate acidophilic microorganism, Acidithiobacillus caldus and Acidithiobacillus ferrooxidans strains ATCC 23270 and ATCC 53993, all extreme acidophiles able to tolerate exceptionally high levels of heavy metals. Some of these bacteria contain variable numbers of GIs, most of which code for high numbers of genes related to metal resistance. In some cases there is an apparent correlation between the number of metal resistance genes and the metal tolerance of each of these microorganisms. It is expected that a detailed knowledge of the mechanisms that these environmental microorganisms use to adapt to their harsh niche will help to improve biomining and metal bioremediation in industrial processes.