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Dimorfismo y patogenia de Histoplasma capsulatum Dimorphism and pathogenesis of Histoplasma capsulatum  [cached]
C. E. López
Revista argentina de microbiolog?-a , 2006,
Abstract: Histoplasma capsulatum es un hongo patógeno dimorfo de importancia en todo el mundo, que causa un amplio espectro de enfermedades. Vive en estado saprobio en fase micelial, presentando hifas con dos tipos de conidios solitarios, macro y microconidias. La infección con H. capsulatum se inicia por vía respiratoria con la inhalación de propágulos fúngicos, constituidos principalmente por microconidios de 1-4 x 2-6 μm o de fragmentos hifales de 5 a 8 μm, que llegan a los bronquiolos terminales y alvéolos pulmonares. Los propágulos inhalados se convierten entonces a la fase levaduriforme, responsable de la patogénesis del H. capsulatum. Por ser un hongo del suelo sin requerimientos conocidos para interactuar con un hospedador mamífero como parte del ciclo de vida obligado, sus estrategias de patogénesis son particularmente notables. Entre éstas se incluyen la transición dimorfa micelio-levadura, entrada en las células fagocíticas del hospedador, localización subcelular, supervivencia y proliferación intracelular durante la infección activa y persistencia durante la infección clínicamente inaparente, con capacidad de reactivación. La patogénesis de H. capsulatum fue estudiada ampliamente a partir del aumento de pacientes inmunosuprimidos. Esta publicación presenta un resumen de los avances realizados en las investigaciones del dimorfismo y la patogénesis de H. capsulatum. Histoplasma capsulatum is a dimorphic fungal pathogen with worldwide significance, which causes a broad spectrum of disease. In the saprophytic stage, it lives as a mycelial form consisting of hyphae bearing both macro and microconidia. Infection with H. capsulatum occurs by inhalation of microconidia (1-4 x 2-6 μm) or small mycelia fragments (5-8 μm) in the terminal bronchioles and alveoli of the lung. Inhaled conidia then convert into the yeast form that is responsible for the pathogenesis of histoplasmosis. As a soil fungus with no known requirements for interacting with a mammalian host as a necessary stage of its life cycle, the number of its strategies for successful pathogenesis is particularly remarkable. They include dimorphic mould-yeast transition, entry into host macrophages, subcellular localization, intracellular survival and proliferation during clinically unapparent infection with capacity for reactivation. H. capsulatum became the subject of increasing studies concurrently with the rising prevalence of human immunodeficiency. This paper presents an overall view of advances in the investigation of H. capsulatum dimorphic transition and pathogenesis.
Aislamientos de Histoplasma capsulatum con morfología aberrante obtenidos en la República Argentina Histoplasma capsulatum with aberrant morphology isolated in Argentina  [cached]
M.F. Zuiani,M.C. Rivas,W. Lee,L. Guelfand
Revista argentina de microbiolog?-a , 2006,
Abstract: Por primera vez en la Argentina se describe una cepa de Histoplasma capsulatum var. capsulatum con morfotipo aberrante, obtenida de un paciente con SIDA. En los primocultivos desarrollados en agar Sabouraud a 25-28 °C, las colonias de la fase micelial fueron blancas, glabras, umbilicadas, centralmente radiadas y de bordes regulares, más semejantes a las de hongos hialinos ambientales que a las de H. capsulatum. Al examen microscópico llamó la atención la ausencia de conidios característicos, la presencia de clamidoconidios solitarios, terminales e intercalares, de 4 μm de diámetro, y el engrosamiento de las hifas. La identificación del hongo se confirmó mediante la detección de exoantígenos específicos (H y M) en los sobrenadantes de cultivos de la fase micelial y por la reversión a la fase levaduriforme típica, obtenida al incubar en agar cerebro-corazón adicionado con cisteína a 37 °C. Mediante RAPD-PCR con los iniciadores 1281-1283, el perfil del ADN genómico coincidió con el genotipo de H. capsulatum predominante entre los aislamientos de pacientes argentinos. For the first time in Argentina, we describe a strain of Histoplasma capsulatum var. capsulatum with an aberrant morphology that was isolated from a single patient with AIDS. Mycelial phase cultures on agar Sabouraud at 25-28 °C showed white, glabrous, umbilicated and centrally radiated colonies. Unusual microscopic findings were the absence of typical conidia, the presence of terminal/intercalary chlamydoconidia with a diameter of 4 μm and of thickened hyphae. Fungal identification was confirmed by the detection of bands H and M species specific antigens in mycelial culture supernatants and reversion to the typical yeast phase on agar brain-heart-cysteine at 37 °C. The genomic DNA profile obtained by RAPD-PCR with primers 1281-1283 coincided with the predominant profile of H.capsulatum among isolates from Argentine patients.
Histoplasma capsulatum en paciente con dermatopolimiositis Histoplasma capsulatum in patient with dermatopolymiosytis
María Claudia Díaz J,Juan Martín Gutiérrez,Libardo Medina,Diana Hernández P
Revista Colombiana de Reumatología , 2009,
Abstract: Se presenta el caso de una paciente de 67 a os, natural y procedente de Santa Ana (Boyacá), con dermatopolimiositis, en la ciudad de Tunja (Boyacá, Colombia), con inmunosupresores, Prednisolona, Metotrexate. A los tres meses del diagnóstico presenta un cuadro infeccioso pulmonar catalogado como neumonía necrotizante de lóbulo superior derecho, la cual progresivamente lleva a la paciente a falla ventilatoria hipercápnica y sepsis de origen pulmonar. Se realiza lavado bronco-alveolar demostrando la presencia de Histoplasma capsulatum; de manera posterior la paciente desarrolla shock cardiogénico y fallece. We present a case of a 67 years old woman with dermatopolymiosytis that after initiated the inmunosupresor treatment develops a necrotizing pneumonia. Histoplasma capsulatum was identified. She received antimycotic treatment but then after develops cardiogenic shock and die.
Contribui??o ao estudo de Histoplasma capsulatum (Darling, 1906)
Pedroso, M. Carlota;Mar?ano, N. Callado;
Memórias do Instituto Oswaldo Cruz , 1972, DOI: 10.1590/S0074-02761972000200008
Abstract: using the amonium sulfate glucose medium we succeed in obtaining stalagmospores in eight sterile strains of histoplasma capsulatum.
Histoplasma capsulatum en paciente con dermatopolimiositis
Díaz J,María Claudia; Martín Gutiérrez,Juan; Medina,Libardo; Hernández P,Diana;
Revista Colombiana de Reumatología , 2009,
Abstract: we present a case of a 67 years old woman with dermatopolymiosytis that after initiated the inmunosupresor treatment develops a necrotizing pneumonia. histoplasma capsulatum was identified. she received antimycotic treatment but then after develops cardiogenic shock and die.
Histoplasma capsulatum proteome response to decreased iron availability
Michael S Winters, Daniel S Spellman, Qilin Chan, Francisco J Gomez, Margarita Hernandez, Brittany Catron, Alan G Smulian, Thomas A Neubert, George S Deepe
Proteome Science , 2008, DOI: 10.1186/1477-5956-6-36
Abstract: To investigate the proteomic response by H. capsulatum to decreasing iron availability we have created H. capsulatum protein/genomic databases compatible with current mass spectrometric (MS) search engines. Databases were assembled from the H. capsulatum G217B strain genome using gene prediction programs and expressed sequence tag (EST) libraries. Searching these databases with MS data generated from two dimensional (2D) in-gel digestions of proteins resulted in over 50% more proteins identified compared to searching the publicly available fungal databases alone. Using 2D gel electrophoresis combined with statistical analysis we discovered 42 H. capsulatum proteins whose abundance was significantly modulated when iron concentrations were lowered. Altered proteins were identified by mass spectrometry and database searching to be involved in glycolysis, the tricarboxylic acid cycle, lysine metabolism, protein synthesis, and one protein sequence whose function was unknown.We have created a bioinformatics platform for H. capsulatum and demonstrated the utility of a proteomic approach by identifying a shift in metabolism the organism utilizes to cope with the hostile conditions provided by the host. We have shown that enzyme transcripts regulated by other fungal pathogens in response to lowering iron availability are also regulated in H. capsulatum at the protein level. We also identified H. capsulatum proteins sensitive to iron level reductions which have yet to be connected to iron availability in other pathogens. These data also indicate the complexity of the response by H. capsulatum to nutritional deprivation. Finally, we demonstrate the importance of a strain specific gene/protein database for H. capsulatum proteomic analysis.Histoplasma capsulatum is a dimorphic fungus and the etiological agent of histoplasmosis. The fungus is endemic to the Midwestern and southeastern United States. H. capsulatum can be a life-threatening infection for individuals suffering from
Reverse genetics through random mutagenesis in Histoplasma capsulatum
Brian H Youseff, Julie A Dougherty, Chad A Rappleye
BMC Microbiology , 2009, DOI: 10.1186/1471-2180-9-236
Abstract: We describe a reverse genetics process that combines the random mutagenesis of Agrobacterium-mediated transformation with screening techniques to identify targeted gene disruptions in a collection of insertion mutants. Isolation of the desired mutant is accomplished by arraying individual clones from a pool and employing a PCR-addressing method. Application of this procedure facilitated the isolation of a cbp1 mutant in a North American type 2 strain, a Histoplasma strain recalcitrant to gene knock-outs through homologous recombination. Optimization of cryopreservation conditions allows pools of mutants to be banked for later analysis and recovery of targeted mutants.This methodology improves our ability to isolate mutants in targeted genes, thereby facilitating the molecular genetic analysis of Histoplasma biology. The procedures described are widely applicable to many fungal systems and will be of particular interest to those for which homologous recombination techniques are inefficient or do not currently exist.The dimorphic fungal pathogen, Histoplasma capsulatum, parasitizes phagocytic cells of the mammalian immune system and causes one of the most common respiratory fungal infections world wide [1-3]. The mycelia-produced Histoplasma conidia are acquired by inhalation into the respiratory tract where exposure to mammalian body temperatures triggers their differentiation into pathogenic yeast cells [3,4]. Histoplasma virulence requires this transition to the yeast phase and expression of the corresponding yeast-phase regulon [5-7]. This transcriptional profile includes genes encoding specific factors that promote Histoplasma virulence [7-9]. While mammalian alveolar macrophages efficiently phagocytose Histoplasma cells, they are unable to kill the yeast [10-12]. Within the macrophage, Histoplasma modifies the intracellular compartment to promote its survival and replication. The ability to subvert immune defenses and to survive within phagocytes enables Histopl
Dimorfismo y patogenia de Histoplasma capsulatum
López,C. E.;
Revista argentina de microbiolog?-a , 2006,
Abstract: histoplasma capsulatum is a dimorphic fungal pathogen with worldwide significance, which causes a broad spectrum of disease. in the saprophytic stage, it lives as a mycelial form consisting of hyphae bearing both macro and microconidia. infection with h. capsulatum occurs by inhalation of microconidia (1-4 x 2-6 μm) or small mycelia fragments (5-8 μm) in the terminal bronchioles and alveoli of the lung. inhaled conidia then convert into the yeast form that is responsible for the pathogenesis of histoplasmosis. as a soil fungus with no known requirements for interacting with a mammalian host as a necessary stage of its life cycle, the number of its strategies for successful pathogenesis is particularly remarkable. they include dimorphic mould-yeast transition, entry into host macrophages, subcellular localization, intracellular survival and proliferation during clinically unapparent infection with capacity for reactivation. h. capsulatum became the subject of increasing studies concurrently with the rising prevalence of human immunodeficiency. this paper presents an overall view of advances in the investigation of h. capsulatum dimorphic transition and pathogenesis.
Infectious keratitis secondary to Histoplasma capsulatum: the first case reports in humans
Arcieri, Enyr S.;Rocha, Ademir;Mendon?a, Camila N.;Andreo, Eduardo G. V.;Finotti, Ioná G.A.;Furlanetto, Rafael L.;Arcieri, Rafael S.;Rocha, Flávio J.;Rizzo, Luiz V.;
Brazilian Journal of Infectious Diseases , 2007, DOI: 10.1590/S1413-86702007000600013
Abstract: the authors report an unusual case of fungal keratitis caused by histoplasma capsulatum in a male immunocompetent patient. pcr confirmed the presence of the fungus dna in the material studied. to our knowledge this is the first reported case in humans described all over the world.
A survey of 800 bats for isolation of Histoplasma Capsulatum in Iran
Hashemi SJ,Emami M
Acta Medica Iranica , 2003,
Abstract: Clinical cases of Histoplasmosis have been reported from many parts of the world principally from the USA and to a lesser extent from central and South America. Sporadic cases are recorded in medical literature from Europe, Africa and Asia. Histoplasma capsulatum, the etiologic agen of histoplasmosis is a cosmopolitan geophilic fungus associated with avian and chiroptera. The association of bats with cases of histoplasmosis in man and the isolation of Histoplasma caplulatum from organs and feces fo naturally infected bats suggest that certain species of chiroptera may play a role in the epidemiology of histoplasmosi. For this purpose during 12 months between 1994 and 1995 a total of 800 bats representing 3 genous include Myotic, Rhinolophus and Sherbersi were examined from 2 caves in the North and West in Iran. The methods were based on direct examination, culture and inoculation to animals and Histoplasma capsulatum was not isolated.
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