scholarly journals Mycelial- to yeast-phase transitions of the dimorphic fungi Blastomyces dermatitidis and Paracoccidioides brasiliensis.

1987 ◽  
Vol 169 (9) ◽  
pp. 4055-4060 ◽  
Author(s):  
G Medoff ◽  
A Painter ◽  
G S Kobayashi
Keyword(s):  
Phase Transitions ◽  
Paracoccidioides Brasiliensis ◽  
Blastomyces Dermatitidis ◽  
Dimorphic Fungi ◽  
Yeast Phase

ON THE CELL WALLS OF DIMORPHIC FUNGI CAUSING SYSTEMIC INFECTIONS

1954 ◽  
Vol 1 (1) ◽  
pp. 1-5 ◽  
Author(s):  
F. Blank
Keyword(s):  
Cell Walls ◽  
Histoplasma Capsulatum ◽  
Paracoccidioides Brasiliensis ◽  
Blastomyces Dermatitidis ◽  
Growth Phases ◽  
Electron Microscopic ◽  
Dimorphic Fungi ◽  
Polymeric Substance ◽  
Systemic Infections ◽  
Microscopic Investigations

Cultures of the mycelial and tissue-like growth phases of Blastomyces dermatitidis, Paracoccidioides brasiliensis, Histoplasma capsulatum, and Sporotrichum Schenckii were extracted and oxidized as described by Scholl in 1908. Debye–Scherrer diagrams of the so prepared cell walls show the presence of chitin in both growth phases of each fungus investigated, and give no evidence of the presence of cellulose or another high polymeric substance in the membranes. Nitrogen determinations of the same material corroborate these findings. Electron-microscopic investigations of the isolated chitin of Blastomyces dermatitidis did not reveal any substantial difference in the submicroscopic structures of the framework of the mycelial and yeast-like growth phases.

Blastomycosis

2020 ◽  
Vol 41 (01) ◽  
pp. 031-041 ◽  
Author(s):  
Ilan S. Schwartz ◽  
Carol A. Kauffman
Keyword(s):  
North America ◽  
Amphotericin B ◽  
Skin Lesions ◽  
Primary Therapy ◽  
Temperature Dependent ◽  
Dimorphic Fungi ◽  
Disseminated Infection ◽  
The Central Nervous System ◽  
Yeast Phase ◽  
Tentative Diagnosis

AbstractBlastomycosis is a serious fungal disease of humans and other mammals caused by environmentally acquired infection with geographically restricted, thermally dimorphic fungi belonging to the genus Blastomyces. The genetic and geographic diversity of these pathogens is greater than previously appreciated. In addition to Blastomyces dermatitidis and the cryptic species Blastomyces gilchristii, which cause blastomycosis in mid-western and various eastern areas of North America, atypical blastomycosis is occasionally caused by Blastomyces helicus in western parts of North America and Blastomyces percursus in Africa. Blastomycosis is acquired by inhalation of the conidia that are produced in the mold phase; in the lungs, temperature-dependent transformation occurs to the yeast phase. In this form, the organism is phagocytized by macrophages and can spread hematogenously to various organs causing disseminated infection. Pulmonary disease is most common and varies from mild, self-limited infection to severe, potentially fatal adult respiratory distress syndrome. Disseminated infection is manifested primarily by skin lesions, but many other organs can be involved. Diagnosis is established by growth of the organism in culture; however, a tentative diagnosis can be made quickly by histopathological identification of the classic yeast form in tissues or by finding Blastomyces antigen in urine or serum. Blastomycosis is treated initially with amphotericin B when the disease is severe, involves the central nervous system, or the host is immunosuppressed. Itraconazole is recommended for primary therapy in mild-to-moderate infection and for step-down therapy after initial amphotericin B treatment. Voriconazole and posaconazole can be used for patients in whom itraconazole is not tolerated.

scholarly journals In Vitro Activities of Voriconazole, Itraconazole, and Amphotericin B against Blastomyces dermatitidis,Coccidioides immitis, and Histoplasma capsulatum

2000 ◽  
Vol 44 (6) ◽  
pp. 1734-1736 ◽  
Author(s):  
Ren-Kai Li ◽  
Meral A. Ciblak ◽  
Nicole Nordoff ◽  
Lester Pasarell ◽  
David W. Warnock ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Histoplasma Capsulatum ◽  
Clinical Laboratory ◽  
Lethal Effect ◽  
Blastomyces Dermatitidis ◽  
National Committee ◽  
Human Pathogens ◽  
Coccidioides Immitis ◽  
Dimorphic Fungi

ABSTRACT The in vitro activity of voriconazole was compared to those of itraconazole and amphotericin B against the mold forms of 304 isolates of three dimorphic fungi, Blastomyces dermatitidis,Coccidioides immitis, and Histoplasma capsulatum. MICs were determined by a broth microdilution adaptation of the National Committee for Clinical Laboratory Standards M27-A procedure. RPMI 1640 medium was used for tests with voriconazole and itraconazole, whereas Antibiotic Medium 3 with 2% glucose was used for amphotericin B. Minimum fungicidal concentrations (MFCs) were also determined. Amphotericin B was active against all three dimorphic fungi, with MICs at which 90% of the isolates tested are inhibited (MIC90s) of 0.5 to 1 μg/ml. Itraconazole had MIC90s of 0.06 μg/ml for H. capsulatum, 0.125 μg/ml for B. dermatitidis, and 1 μg/ml for C. immitis. The MIC90s of voriconazole were 0.25 μg/ml for all three fungi. Amphotericin B was fungicidal for B. dermatitidis and H. capsulatum with MFCs at which 90% of strains tested are killed (MFC90s) of 0.5 and 2 μg/ml, respectively. It was less active against C. immitis, with MFCs ranging from 0.5 to >16 μg/ml. Voriconazole and itraconazole were lethal for most isolates of B. dermatitidis, with MFC50s and MFC90s of 0.125 and 4 μg/ml, respectively. Both azoles were fungicidal for some isolates of H. capsulatum, with MFC50s of 2 and 8 μg/ml for itraconazole and voriconazole, respectively; neither had a lethal effect upon C. immitis. Our results suggest that voriconazole possesses promising activity against these important human pathogens.

Paracoccin overexpression in Paracoccidioides brasiliensis enhances fungal virulence by remodeling chitin properties of the cell wall

2020 ◽  
Author(s):  
Relber Aguiar Gonçales ◽  
Rafael Ricci-Azevedo ◽  
Vanessa C S Vieira ◽  
Fabrício F Fernandes ◽  
Sandra M de O Thomaz ◽  
...  
Keyword(s):  
Cell Wall ◽  
Paracoccidioides Brasiliensis ◽  
Chitinase Activity ◽  
Growth Media ◽  
Lung Pathology ◽  
Dimorphic Fungi ◽  
Fungal Virulence ◽  
Paracoccidioides Spp ◽  
Cell Growth And Viability ◽  
Etiological Agents

Abstract Background The thermo-dimorphic fungi Paracoccidioides spp. are the etiological agents of paracoccidioidomycosis. Although poorly studied, paracoccin (PCN) from P. brasiliensis has been shown to harbor lectinic, enzymatic, and immunomodulatory properties that impact disease development. Methods Mutants of P. brasiliensis overexpressing PCN (ov-PCN) were constructed by Agrobacterium tumefaciens-mediated transformation. Ov-PCN strains were analyzed and inoculated intranasally or intravenously to mice. Fungal burden, lung pathology, and survival were monitored to evaluate virulence. Electron microscopy was used to evaluate the size of chito-oligomer particles released by ov-PCN or wild-type strains to growth media. Results ov-PCN strains revealed no differences in cell growth and viability, although PCN overexpression favored cell separation, chitin processing that results in the release of smaller chito-oligomer particles, and enhanced virulence. Our data show that PCN triggers a critical effect in the cell wall biogenesis through the chitinase activity resulting from overexpression of PCN. As such, PCN overexpression aggravates the disease caused by P. brasiliensis. Conclusions Our data is consistent with a model in which PCN modulates the cell wall architecture via its chitinase activity. These findings highlight the potential for exploiting PCN function in future therapeutic approaches.

scholarly journals Identification of the Mating-Type (MAT) Locus That Controls Sexual Reproduction of Blastomyces dermatitidis

2012 ◽  
Vol 12 (1) ◽  
pp. 109-117 ◽  
Author(s):  
Wenjun Li ◽  
Thomas D. Sullivan ◽  
Eric Walton ◽  
Anna Floyd Averette ◽  
Sharadha Sakthikumar ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Genetic Recombination ◽  
Sexual Cycle ◽  
Blastomyces Dermatitidis ◽  
Comparative Genomic ◽  
Dimorphic Fungi ◽  
Content Type ◽  
Long Time ◽  
Northern United States

ABSTRACTBlastomyces dermatitidisis a dimorphic fungal pathogen that primarily causes blastomycosis in the midwestern and northern United States and Canada. While the genes controlling sexual development have been known for a long time, the genes controlling sexual reproduction ofB. dermatitidis(teleomorph,Ajellomyces dermatitidis) are unknown. We identified the mating-type (MAT) locus in theB. dermatitidisgenome by comparative genomic approaches. TheB. dermatitidis MATlocus resembles those of other dimorphic fungi, containing either an alpha-box (MAT1-1) or an HMG domain (MAT1-2) gene linked to theAPN2,SLA2, andCOX13genes. However, in some strains ofB. dermatitidis, theMATlocus harbors transposable elements (TEs) that make it unusually large compared to theMATlocus of other dimorphic fungi. Based on theMATlocus sequences ofB. dermatitidis, we designed specific primers for PCR determination of the mating type. TwoB. dermatitidisisolates of opposite mating types were cocultured on mating medium. Immature sexual structures were observed starting at 3 weeks of coculture, with coiled-hyphae-containing cleistothecia developing over the next 3 to 6 weeks. Genetic recombination was detected in potential progeny by mating-type determination, PCR-restriction fragment length polymorphism (PCR-RFLP), and random amplification of polymorphic DNA (RAPD) analyses, suggesting that a meiotic sexual cycle might have been completed. The F1 progeny were sexually fertile when tested with strains of the opposite mating type. Our studies provide a model for the evolution of theMATlocus in the dimorphic and closely related fungi and open the door to classic genetic analysis and studies on the possible roles of mating and mating type in infection and virulence.

scholarly journals Molecular and Morphological Data Support the Existence of a Sexual Cycle in Species of the Genus Paracoccidioides

2012 ◽  
Vol 12 (3) ◽  
pp. 380-389 ◽  
Author(s):  
Marcus de Melo Teixeira ◽  
Raquel Cordeiro Theodoro ◽  
Lorena da Silveira Derengowski ◽  
André Moraes Nicola ◽  
Eduardo Bagagli ◽  
...  
Keyword(s):  
Paracoccidioides Brasiliensis ◽  
Sexual Cycle ◽  
Morphological Data ◽  
Comparative Genomic ◽  
Mating Types ◽  
Isolated Populations ◽  
Dimorphic Fungi ◽  
Filamentous Form ◽  
Content Type

ABSTRACTThe genusParacoccidioidesincludes the thermodimorphic speciesParacoccidioides brasiliensisandP. lutzii, both of which are etiologic agents of paracoccidioidomycosis, a systemic mycosis that affects humans in Latin America. Despite the common occurrence of a sexual stage among closely related fungi, this has not been observed withParacoccidioidesspecies, which have thus been considered asexual. Molecular evolutionary studies revealed recombination events within isolated populations of the genusParacoccidioides, suggesting the possible existence of a sexual cycle. Comparative genomic analysis of all dimorphic fungi andSaccharomyces cerevisiaedemonstrated the presence of conserved genes involved in sexual reproduction, including those encoding mating regulators such as MAT, pheromone receptors, pheromone-processing enzymes, and mating signaling regulators. The expression of sex-related genes in the yeast and mycelial phases of bothParacoccidioidesspecies was also detected by real-time PCR, with nearly all of these genes being expressed preferentially in the filamentous form of the pathogens. In addition, the expression of sex-related genes was responsive to the putative presence of pheromone in the supernatants obtained from previous cocultures of strains of two different mating types.In vitrocrossing of isolates of different mating types, discriminated by phylogenetic analysis of the α-box (MAT1-1) and the high-mobility-group (HMG) domain (MAT1-2), led to the identification of the formation of young ascocarps with constricted coiled hyphae related to the initial stage of mating. These genomic and morphological analyses strongly support the existence of a sexual cycle in species of the genusParacoccidioides.

scholarly journals Variation in Host Resistance to Blastomyces dermatitidis: Potential Use of Genetic Reference Panels and Advances in Immunophenotyping of Diverse Mouse Strains

mBio ◽  
2022 ◽  
Author(s):  
Elaine M. Kohn ◽  
Cleison Taira ◽  
Hanah Dobson ◽  
Lucas Dos Santos Dias ◽  
Uju Okaa ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Infectious Diseases ◽  
Fungal Infection ◽  
Host Resistance ◽  
Blastomyces Dermatitidis ◽  
Mouse Strains ◽  
Dimorphic Fungi ◽  
Host Genetic ◽  
Potential Use

Host genetic variation significantly impacts vulnerability to infectious diseases. While host variation in susceptibility to fungal infection with dimorphic fungi has long been recognized, genes that underpin this variation are poorly understood.

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