RESUMO
Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis, a disease confined to Latin America and of marked importance in the endemic areas due to its frequency and severity. This species is considered to be clonal according to mycological criteria and has been shown to vary in virulence. To characterize natural genetic variation and reproductive mode in this fungus, we analyzed P. brasiliensis phylogenetically in search of cryptic species and possible recombination using concordance and nondiscordance of gene genealogies with respect to phylogenies of eight regions in five nuclear loci. Our data indicate that this fungus consists of at least three distinct, previously unrecognized species: S1 (species 1 with 38 isolates), PS2 (phylogenetic species 2 with six isolates), and PS3 (phylogenetic species 3 with 21 isolates). Genealogies of four of the regions studied strongly supported the PS2 clade, composed of five Brazilian and one Venezuelan isolate. The second clade, PS3, composed solely of 21 Colombian isolates, was strongly supported by the alpha-tubulin genealogy. The remaining 38 individuals formed S1. Two of the three lineages of P. brasiliensis, S1 and PS2, are sympatric across their range, suggesting barriers to gene flow other than geographic isolation. Our study provides the first evidence for possible sexual reproduction in P. brasiliensis S1, but does not rule it out in the other two species.
Assuntos
Especiação Genética , Variação Genética , Paracoccidioides/genética , Filogenia , Recombinação Genética , Sequência de Bases , Teorema de Bayes , Primers do DNA , Modelos Genéticos , Dados de Sequência Molecular , Análise de Sequência de DNA , América do Sul , Especificidade da EspécieRESUMO
Chlamydia pneumoniae es un patógeno mundialmente reconocido como causante de infecciones del tracto respiratorio en humanos, se caracteriza por ser un microorganismo intracelular obligado. Al presente, se ha comprobado su presencia en placas ateromatosas por múltiples técnicas como la inmunohistoquímica, la microscopía electrónica y la reacción en cadena de la polimerasa (PCR). La enfermedad aterosclerótica, es responsable de muchos de los accidentes cerebrovasculares y cardiovasculares. Sin embargo el papel patogénico de este microorganismo en dicha enfermedad aun no es claro. En este estudio, por medio de ka reacción en cadena de la polimerasa (PCR) se logró comprobar la presencia de C. pneumoniae en el 28 por ciento de 93 muestras de tejido vascular provenientes de pacientes que fueron sometidos a cirugía de revascularización quirúrgica. La presencia de este microorganismo en tejido vascular de pacientes con enfermedad coronaria podría considerarse como un factor de riesgo cardiovascular para el desarrollo de aterosclerosis y enfermedades cerebrovasculares
Assuntos
Arteriosclerose/etiologia , Chlamydophila pneumoniae/isolamento & purificação , Chlamydophila pneumoniae/patogenicidade , Infecções por Chlamydia , Reação em Cadeia da PolimeraseRESUMO
Paracoccidioides brasiliensis is the causative agent of paracoccidioidomycosis, an important mycosis endemic to Latin America. As the tools to study gene function in P. brasiliensis are only in the early stage of development, there is presently no system that allows for both the delivery and integration of exogenous nucleic acids into its genome. We report in this paper the transformation of the yeast phase of P. brasiliensis (ATCC-60855) with Agrobacterium tumefaciens (GV3101) carrying the vector pAD1625. The microorganisms were co-cultivated for 2 days and then incubated for 10 days at 35 degrees C on selective media. PCR and dot-blot targeted at a fragment of 222 bp from the hph (hygromycin phosphotransferase) gene which confers Hygr confirmed the transformation of P. brasiliensis.