Avaliacao das subpopulacoes de timocitos em camundongos BALB/c infectados com Paracoccidioides brasiliensis por via intratraqueal / Evaluation of thymocyte subpopulations in BALB / c mice infected with Paracoccidioides brasiliensis intratracheally

O P. brasiliensis e o agente etiologico da paracoccidioidomicose, uma doenca granulomatosa cronica que afeta primariamente os pulmoes e esta frequentemente relacionada com a diminuicao da resposta imune celular especifica. A inoculacao intraperitonial deste fungo em camundongos causa a trofia do timo, orgao respónsavel pela geracao de linfocitos T que dirigem a reposta imune especifica. Assim, este trabalho teve como objetivo avaliar a ocorrencia de atrofia timica em camundongos infectados com P. brasiliensis pela via intratraqueal, que constituium modelo mais fiel da doenca. A infeccao por esta via, resultou claramente em atrofia timica, que foi caracterizada por uma diminuicao do peso, celularidade e viabilidade celular, alem de alteracoes nas subpopulacoes dos timocitos, como diminuicao dos duplos dispositivos (CD4+CD8+) e consequente aumento dos duplos negativos (CD4-CD8-) e timocitos CD4+CD8- e CD4-CD8+.

Cell cycle, DNA replication, repair, and recombination in the dimorphic human pathogenic fungus Paracoccidioides brasiliensis

DNA replication, together with repair mechanisms and cell cycle control, are the most important cellular processes necessary to maintain correct transfer of genetic information to the progeny. These processes are well conserved throughout the Eukarya, and the genes that are involved provide essential information for understanding the life cycle of an organism. We used computational tools for data mining of genes involved in these processes in the pathogenic fungus Paracoccidiodes brasiliensis. Data derived from transcriptome analysis revealed that the cell cycle of this fungus, as well as DNA replication and repair, and the recombination machineries, are highly similar to those of the yeast Saccharomyces cerevisiae. Among orthologs detected in both species, there are genes related to cytoskeleton structure and assembly, chromosome segregation, and cell cycle control genes. We identified at least one representative gene from each step of the initiation of DNA replication. Major players in the process of DNA damage and repair were also identified.

The cell wall of Paracoccidioides brasiliensis: insights from its transcriptome

The cell wall of a human pathogenic fungus is in contact with the host, serves as a barrier against host defense mechanisms and harbors most fungal antigens. In addition, cell wall biosynthesis pathways have been recognized as essential to viability and as specific drug targets. Paracoccidioides brasiliensis is a dimorphic fungus that presents mycelium morphology in the free environment and causes infection in a yeast form. The morphogenetic conversion is correlated with changes in the cell wall composition, organization and structure. Based on transcriptome analysis, the enzymes involved in the biosynthesis and remodeling of cell wall polysaccharides, as well as several cell wall-associated molecules of P. brasiliensis, were identified and addressed in further detail.

The low efficiency of dendritic cells and macrophages from mice susceptible to Paracoccidioides brasiliensis in inducing a Th1 response

In the present study we evaluated T cell proliferation and Th lymphokine patterns in response to gp43 from Paracoccidioides brasiliensis presented by isolated dendritic cells from susceptible and resistant mice. T cell proliferation assays showed that dendritic cells from susceptible mice were less efficient than those from resistant mice. The pattern of T cell lymphokines stimulated by dendritic cells was always Th1, although the levels of IL-2 and IFN-gamma were lower in T cell cultures from susceptible mice. To determie whether different antigen-presenting cells such as macrophages and dendritic cells stimulated different concentrations of Th1 lymphokines, the production of IFN-gamma and IL-2 was measured. It was observed that dendritic cells were more efficient than macrophages in stimulating lymphoproliferation in resistant mice. However, no significant difference was observed for IFN-gamma or IL-2 production. When cells from susceptible mice were used, macrophages were more efficient in stimulating lymphoproliferation than dendritic cells, but no difference was observed in the production of Th1 cytokine. Taken together, these results suggest the lower efficiency of dendritic cells and macrophages from B10.A mice in stimulating T cells that secrete Th1 lymphokines in vitro, an effect that may be involved in the progression of the disease in vivo

Paracoccidioides brasilienses isolates obtained from patients with acute and chronic disease exhibit morphological differences after animal passage

The basis for virulence in Paracoccidioides brasiliensis is not completely understood. There is a consensus that the sequencial in vitro subcultivation of P. brasiliensis leads to loss of its pathogenicity, which can be reverted by reisolation from animal passage. Attention to morphological and biochemical properties that are regained or demonstrated after animal passage may provide new insights into factors related to the pathogenicity and virulence of P. brasiliensis. We evaluated morphological characters: the percentage of budding cells, number of buds by cell and the diameter of 100 mother cells of yeast-like cells of 30 P. brasiliensis isolates, before and after animal passage. The isolates were obtained from patients with different clinical forms of paracoccidioidomycosis (PCM): acute form (group A, n=15) and chronic form (group C, n=15). The measurement of the yeast cell sizes was carried out with the aid of an Olympus CBB microscope coupled with a micrometer disc. We measured the major transverse and longitudinal axes of 100 viable cells of each preparation. The percentage of budding cells as also the number of buds by cell was not influenced by animal passage, regardless of the source of the strain (acute or chronic groups). The size values of P. brasiliensis isolates from groups A and C, measured before the animal passage exhibited the same behavior. After animal passage, there was a statistically significant difference between the cell sizes of P. brasiliensis isolates recovered from testicles inoculated with strains from groups A and C. The maximum diameter of mother cells from group A isolates exhibited a size of 42.1um in contrast with 32.9um exhibited by mother cells from group C (p<0.05). The diameter of 1500 mother cells from group A isolates exhibited a medium size of 16.0um (SD + or - 4.0), a value significantly higher than the 14.1um (SD = + or - 3.3) exhibited by 1500 mother cells from group C isolates (0.05). Our results reinforce the polymorphism exhibited by P. brasiliensis in biological material and the need for further investigations to elucidate the role of morphological parameters of the fungus in the natural history of the disease

Extraction and characterization of proteins from cell walls of two strains of paracoccidioides brasiliensis

En el presente trabajo se analizaron las proteínas de la pared celular de 2 cepas de paracoccidioides brasiliensis en fase levaduriforme (PbHC-PE y Pb 18). Las proteínas fueron extraidas por tres difrentes métodos y estudiadas por electroféresis SDS-PAGE. Los resultados de los perfiles de las dos cepas fueron diferentes, permitiendo la posibilidad de su uso como marcadores quimiotaxonómicos. Se observó una secreción transitoria de la proteína gp 43 a través de la pared celular de las cepas de p. brasiliensis.

Determinação da viabilidade do Paracoccidioides loboi em biopsias de pacientes portadores de doença de Jorge Lobo / Determination of the viability of the Paracoccidioides loboi in biopsias of carrying patients of illness of Jorge Wolf

Fundamentos- Na doença de Jorge Lobo, devido ao não cultivo do P.loboi, utiliza-se material obtido de biopsias de pacientes, sendo a determinação da viabiliadade imprescindivel para os estudo experimentais da doença. Objetivos- Determinar a viabilidade do P. loboi, por meio de diferentes metodos de coloração, e investigar a influencia da temperatura e de diferentes soluções na viabilidade do fungo. Casuistica e Metodos- Biopsias de 15 pacientes foram processadas em solução salina 0,85%(SS), solução salina de Hank´s(SSH) e solução salina glicerinada a 30% com vitamina B(SSG). A viabilidade foi determinada no momento da coleta da biopsia (tempo 0), empregando-se os corantes diacetato de fluoresceina-brometo de etideo (DF-BE), lactofenol azul-algodão, azul-tripan e verde-janus. As suspensões foram mantidas a 4°C, 23°C e 37°C, e a viabilidade foi determinada a cada tres dias, utilizando-se a coloração DF-BE. Resultados - A viabilidade do P. loboi no tempo 0 variou de 21 a 46%, utilizando-se a coloração de DF-BE. A viabilidade com os demais corantes não foi satisfatoria, devido a dificuldades em separar os fungos viaveis dos não viaveis. A temperatura de 4°C foi mais eficaz em manter a viabilidade do fungo (ate 15 dias). Por outro lado, nenhuma das soluções empregadas conseguiu manter a viabilidade do fungo ou favorecer sua multiplicação. Conclusões - A determinação da viabilidade do P. loboi com DFG-BE podera auxiliar nas tentativas de cultura do fungo, nas inoculações em animais e no controle terapeutico da doença. Alem disso, a temperatura parece ser fator importante no crescimento do P. loboi.

Hipereosinofilia na paracoccidioidomicose: relato de um caso / Hypereosinophilia in the paracoccidioidomycosis: case report

É relatado um caso de paracoccidioidomicose disseminada (tipo juvenil) em cujo transcurso foi observado número excepcionalmente elevado de eosinófilos no sangue. Casos incomuns como esse foram revistos

Estudio de nueve casos de "Blastomicosis Sudamericana" Hospital Nacional Guillermo Almenara Irigoyen / Study of nine cases of \"Sudamerican blastomycosis\" at Hospital Guillermo Almenara Yrigoyen

Durante los años 1973 y 1985, se estudiaron nueve pacientes con diagnóstico presuntivo de Blastomicosis Sudamericana. Se realizó el presente estudio con la finalidad de llegar al diagnóstico etiológico. Se efectuó las investigaciones tomando muestras por raspado de las lesiones y el esputo. Se utilizó las coloraciones de Gram y Wrigh y se hizo inoculaciones en el testículo de cobayo. Encontramos el PARACOCCIDIOIDES BRASILIENSIS en los nueve casos; tres de ellos presentaron lesiones labio-pulmón; tres en pulmón; dos en labio; y uno en brazo. En los nueve casos se confirmó el diagnóstico etiológico.

Un modelo de dimorfismo en hongos patógenos: Paracoccidioides brasiliensis / A model of dimorphism in pathogenic fungi: Paracoccidioides brasiliensis

Se exploró la existencia de factores citoplasmáticos que controlan la síntesis de glucán en Paracoccidioides brasiliensis. Se observó que el sistema estaba regulado por la presencia de proteinasas e inhibidores de proteinasas; diferentes según la fase levaduriforme o micelial del hongo. Con los datos obtenidos se complementa el modelo de dimorfismo en P. brasiliensis postulado anteriormente